A

TECHNICAL REPORT

ON

DESIGN OF PLANT FOR THE PRODUCTION OF 72000 TONNES/ YEAR OF 2-

ETHYLHEXANOL FROM PROPYLENE AND SYNTHESIS GAS:

Prepared by

OGUNGBENRO, ADETOLA ELIJAH

(REG. NUMBER: CHE/2007/083)

Submitted To

PROFESSOR FUNSO AKEREDOLU

IN PARTIAL FULFILLMENT OF THE REQUIREMENTS OF THE COURSE

PROCESS DESIGN I&II

(CHE 505/506)

DEPARTMENT OF CHEMICAL ENGINEERING,

OBAFEMI AWOLOWO UNIVERSITY, ILE IFE, NIGERIA

DECEMBER 2012.

i
 OGUNGBENRO Adetola Elijah
Department of Chemical Engineering,
Obafemi Awolowo University, Ile-ife.
December 1, 2012.

Professor Funso Akeredolu,

Course Supervisor, Process Design I & II (CHE 505/506)
Department of Chemical Engineering,
Obafemi Awolowo University, Ile-ife.
Dear Sir,

LETTER OF TRANSMITTAL

I, OGUNGBENRO Adetola Elijah, with Registration Number CHE/2007/083

humbly submit for assessment this complete design report on process plant for the

production of 72,000 tons per year of 2-Ethylhexanol from synthesis gas and propylene

feed.

I hereby certify that all information contained therein are based on knowledge

gained from interactive discussions and personal research.

I hope this report meets your satisfaction and approval Sir.

Thanks and God bless.

Yours faithfully,

OGUNGBENRO, ADETOLA ELIJAH

(CHE/2007/083)

ii
 EXECUTIVE SUMMARY

A critical approach is attempted in this project work at realizing the design objectives for

a process plant. Design, being an iterative procedure with a route of procession from the

input or feed to the stated objective(s), amidst intervening constraints, requires a careful,

well- thought- out, comprehensive specifications of the defined or desired requirements.

The stated objective in this case is the design of a 72000 tons/year capacity of a 2-

EthylHexanol (C8H18O) Plant. While many processes exist at producing 2-

EthylHexanol (2- EH), such as the Acetaldehyde Route and others developed by Shell

Corporation etc, the Oxo Process route utilizing propylene and synthesis gas as feed

components was the given route for this design work. However, important modifications

were implemented to the process description for effective process optimization, such as

to improve the conversion of efficiencies of process equipment by aid of recycle

processes.

The oxo synthesis began by reacting propylene feed and synthesis gas (CO + H2) in a

Cobalt Carbonyl (Co2(CO)8) catalyzed hydroformylation reaction. The propylene feed

input of 198.3275 kmols/hr was made up by three streams; Fresh Feed of 152.9 kmols/hr,

recycle streams from cracking unit of 42.9775 kmols/hr, and stripped propylene from

Gas- Liquid Separator 2 of 2.45 kmols/hr.

310.709 kmols/hr of synthesis gas (CO + H2) was supplied together with 218.5415

kmols/hr excess Hydrogen for use in latter processes. The hydroformylation reactor was

iii
at operating temperature and pressure of 130°C and 350 bar. The design temperature and

pressure however was heuristically accepted as 1.1 times of this value.

The main product of the oxo reactor was n- butyraldehyde with molar flow rate of

141.6840 kmols/hr. A side reaction produced iso- butyraldehyde of 36.1750 kmols/hr,

with a selectivity ratio of 4:1. Alcohols formed from the hydroformylation reaction

included n- butanol (9.0437), and iso butanol of 1.5073 kmols/hr. Other reactions occured

to a small extent yield 136.0750 kg of high molecular weight or heavy end compounds,

representing 1 weight % of the butyraldehyde/ butanol mixture.

A cleaner technology approach to pollution control was adopted for the plant design.

Hence, the need for thorough separation processes and purge streams to remove

extraneous components. From the hydroformylation reactor, the products were separated

with the first Gas- Liquid Separator (GLS 1), which separated the aqueous phase of

cobalt and water from the organic phase components in a process referred to as cobalt

plating. The cobalt was regenerated as an active catalyst, to save cost, and sent back to

the oxo reactor for further reaction. The organic phase of GLS-1 goes for further

separation in a second GLS which stripped the initial reactants (propylene and synthesis

gas) for recycle back to oxo reactor. Liquid phase of n-/iso- butyraldehyde, alcohols,

heavy ends and remnant water exits the GLS 2 operating at 55°C and 1 bar.

A vital separation technique was involved proceeded from GLS-2. A distillation column

1 (DC 1) with 36 trays and made of Ferritic Stainless Steel 430 is employed which gave a

top product of n-/iso- butyraldehyde and bottoms of alcohols etc. Further distillation was

employed to separate normal and iso- butyraldehyde in DC 2. The McCabe Thiele- Plot
iv
is of stream properties of DC 2 indicated the number of required trays as 42. Tray

thickness and spacing of 3 mm and 457.2 mm was employed for both the enriching and

rectifying section of the 25.89 m heighted DC 2. Sieve hole pitch was 15mm while

diameter was 5mm. Flooding rate of 80% was computed for both sections and it was

ratified that there was no flooding. The Murphee plate efficiency and overall column

efficiency was within acceptable ranges (> 80 %). Log Mean Temperature Difference

(LMTD) for the partial condenser was 31.51°C. Mechanical design specifications for the

DC 2 construction were computed in this report. The top product of DC 2 was mainly

iso- butyraldehyde (35.704 kmols/hr), while the bottoms was mainly n- butyraldehyde

(141.304 kmols/hr) required for 2- EH production.

To maximize output of 2- EH, the iso- butanal obtained from DC 2 operation was routed

through a cracking/ conversion process to produce original reactants. The 6461 L

capacity cracker unit had operating specifications of 275°C and 1 bar, but designed at 1.1

bar and 302.5 °C and made of Low- Alloy Steel material for good heat retention. A

recycle process was proposed for the cracker unit which had a limited conversion yield of

80%. Aldol condensation with 2 % w/w aqueous NaOH (9.2 kmols/ hr) took place on the

n- butanal product from DC 2. The Aldol condenser reactor produced 69.946 kmols/hr of

2- Ethyl hexanal, an intermediate reactant for 2- EH. (Improved recycle process for the

90% Efficient Aldol Condenser was also proposed). Subsequently, 2- Ethylhexanal

undergoes hydrogenation to give 69.247 kmols/ hr of 2- Ethyl hexanol, recovery rate of

99.8 % and 99% wt purity.

v
Process design for the 2- EH also involved the control and instrumentation of the

processes and equipment to achieve the design objectives and safety. Control of operating

conditions of the oxo reactor was described, with preferred controller as Proportional

Integral Derivative (PID) Controller. A PID controller was chosen for operation to

eliminate the challenge of runaway temperature increase by the derivative component and

the offset error by the integral component. Simulation results suggested the

hydroformylation (HFR) vessel temperature was kept at safe operating condition using

coolant stream and a Temperature controller (TC) with Controller Gain Kc = 2 and

Settling Time Ti = 5min. A controller scheme was also designed for level control to avoid

the splashing of the reactants and prevent the mixing of pure tops from the bottoms. The

proposed controller was proportional controller which can tolerate offset. This controller

allows offset depending on the magnitude of the controller gain which is the only

controller parameter to be varied in this case. HFR liquid level was kept at safe fill of

85% using a bottom product valve (BPV) and a PID level controller (LC) with Kc = 2

and Ti = 10min. The mass flow rates of propylene stream and synthesis gas stream going

into hydroformylation reactor (HFR) were controlled by propylene stream valve (PV) and

synthesis gas stream valve (SGV) respectfully using a PID controller of 0.1 Kc

(Controller gain) and 5min integral time for both streams.

An acceptable design must present a process that is capable of operating under conditions

which will yield a profit. A simple costing procedure is carried out for the 2- EH Plant to

determine if the design is feasible economically or not based on certain estimates.

vi
Estimates were prepared using data and Chemical Engineering cost index method in

Literature, considering Port Harcourt (Rivers State, Nigeria) as the location of the plant.

Old cost information was obtained and extrapolated using the Index Method to the

present 2012 costs. These costs were then converted to Naira using appropriate foreign

exchange rates.

The Purchased Cost of Equipment (PCE) was valued at #428,171,790, while the Physical

Plant Costs (PPC) or direct costs was obtained by the factorial costing method at 3.4

times PCE, and valued at #1,455,784,086. Indirect costs were the expenses which are

not directly involved with material and labor which included design and engineering,

contractor’s fee etc, and were valued at #650,602,838.70k. The Fixed Capital Investment

(FCI) was obtained by summing up the direct and indirect costs, and valued at

#2,106,386,925.70k. The Working Capital was 15% of the FCI and both gave the Total

Capital Investment of #2,442,344,964.81k.

The start- up cost, or for first- run of plant for production, was valuated at 15% of TC1.

With a selling price at #130.56k, the 72,000 tons/year 2- Ethylhexanol plant is expected

to have a net profit of ##5,146,221,476.

Finally, procedures for safe operation and start- up of the 72000 tons/year 2-

Ethylhexanol Plant were documented.

vii
 CONTENTS

Title Page i

Letter of Transmittal ii

Executive Summary iii

Contents viii

List of Tables xvii

List of Figures xix

Abbreviations xxi

CHAPTER ONE: INTRODUCTION 1

1.1 Background 1

1.2 2- Ethylhexanol Properties and Uses 4

1.2.1 Physical and chemical properties 4

1.2.2 Environmental fate 4

1.2.3 Uses of 2- Ethylhexanol 6

viii
CHAPTER TWO: LITERATURE REVIEW 8

2.1 Choice of Synthesis Route 8

2.1.1 Acetaldehyde route 8

2.1.2 Aldox process 9

2.1.3 Shell process 9

2.1.4 Oxo process 10

2.2 Specifications, Analytical, and Test Methods 14

2.3 Process Selection 15

2.4 Process Description 18

2.4.1 Problem statement 18

2.4.2 The process 18

2.4.3 Feed specifications 20

2.4.4 Utilities 20

2.5 Scope of the Design Work 20

2.5.1 Process design 20

2.5.2 Chemical engineering design 21

2.5.3 Mechanical design 21

2.5.4 Control system 21

2.5.5 Cost estimate 21

2.6 Data Supplied 22

2.6.1 Chemical reactions 22

2.6.2 Boiling points at 1 bar 23

ix
 2.6.3 Solubilities of gases at 30 Bar in the liquid

phase of the first gas-liquid separator 23

2.6.4 Vapor-liquid equilibrium of the butyraldehydes

at 1 atm 24

CHAPTER THREE: PROPOSAL 25

3.1 Process Description 25

3.1.1 Hydroformylation reactor 25

3.1.2 Gas liquid separator 1 (GLS-1) 28

3.1.3 Gas liquid separator 2 (GLS- 2) 28

3.1.4 Distillation column 1 (DC 1) 29

3.1.5 Distillation column 2 (DC 2) 29

3.1.6 Cracker unit 29

3.1.7 Aldol reactor 30

3.1.8 Hydrogenation reactor 30

3.2 Miscellaneous Equipment 31

x
CHAPTER FOUR: PROCESS DESIGN BALANCES 34

4.1 Material Balance 35

4.1.1 Hydrogenation 38

4.1.2 Aldol reactor 39

4.1.3 Distillation column (DC 2) 40

4.1.4 Cracker 43

4.1.5 Distillation column (DC) 1 44

4.1.6 Oxo reactor 45

4.1.7 Gas- liquid separator (GLS) 1 50

4.1.8 Gas- liquid separator (GLS) 2 53

4.1.9 Material balance analysis 53

4.2 Energy Balance 56

4.2.1 Hydroformylation reactor 56

4.2.2 Cracker 64

4.2.3 Energy balance analysis 68

CHAPTER FIVE: EQUIPMENT SCHEDULE AND P&ID 69

5.1 Design Conditions and Physical Properties of Oxo Reactor 69

5.2 Design Conditions and Physical Properties of Cracker 71

5.3 Design Conditions and Physical Properties of

Aldol Condenser 73

xi
 5.4 Design Conditions and Physical Properties of

Hydrogenation Reactor 74

5.5 Capacity of Storage Tanks 75

5.5.1 Propylene feed storage tank 75

5.5.2 Synthesis gas storage tank 77

5.5.3 Hydrogen gas storage tank 77

5.4.4 2-Ethyl hexanol product storage tank 78

5.6 Materials of Construction 79

CHAPTER SIX: CHEMICAL ENGINEERING DESIGN 84

6.1 Plate Hydraulics 91

6.1.1 Enriching section 91

6.1.2 Stripping section 102

6.2 Condenser Preliminary Calculations 111

6.3 Summary of Chemical Engineering Design of DC 2 119

6.4 Notations 119

xii
CHAPTER SEVEN: MECHANICAL DESIGN OF N- AND ISO-

BUTYRALDEHYDE DISTILLATION COLUMN 124

7.1 Specification Details 124

7.1.1 Shell 124

7.1.2 Calculation of stresses 126

7.1.3 Design of skirt support 132

7.1.4 Design of skirt bearing plate 136

7.2 Mechanical Design for the Condenser 140

7.2.1 Shell side 140

7.2.2 Tube side 145

CHAPTER EIGHT: INSTRUMENTATION SCHEDULE AND

CONTROL SCHEME 151

8.1 Background 151

8.2 Control of the Reactor System Temperature 152

8.2.1 Sensor 154

8.2.2 The controller 155

8.2.3 The control valve 155

8.2.4 The cooling process 157

8.3 Control Scheme for the Liquid Level within the Reactor 158

xiii
CHAPTER NINE: COST ESTIMATION AND ECONOMIC

EVALUATION OF THE PROCESS 160

9.1 Background 160

9.2 Cost Estimate of Plant Equipment 161

9.3 Estimation of Purchased Costs of Equipment (PCE) 162

9.4. Estimation of Total Investment Cost 171

9.4.1 Direct costs 171

9.4.2 Indirect costs 173

9.5 Estimation of Total Production Cost 175

9.6 Profitability Analysis 180

CHAPTER TEN: PLANT START- UP AND OPERATING

PROCEDURES 182

10.1 Background 182

10.2 General Principles 185

10.3 Start- Up 190

10.3.1 Preparation prior to initial start-up 191

10.3.1.1 Operational check-out 192

10.3.1.2 Hydrostatic testing 193

10.3.1.3 Final inspection of vessels 196

10.3.1.4 Flushing of lines 197

xiv
 10.3.1.5 Instruments 201

10.3.1.6 Acid cleaning of compressor lines 202

10.3.1.7 General notes for dry-out

and boil-out 202

10.3.1.8 Catalyst loading 203

10.3.1.9 Tightness test 203

10.3.2 Normal start-up procedures 204

10.3.2.1 Prestart-up check list 205

10.3.2.2 Make area safe 206

10.3.2.3 Utilities commissioning 206

10.3.2.4. Establish flow in the unit 206

10.3.2.5 Adjust operation to obtain quality 207

10.4 Performance Trails 207

10.5 Safety Practices 208

10.6 Shut Down and Emergency Procedures 209

10.6.1 Scheduled shutdown 210

10.6.2 Maintenance shutdown 211

10.6.3 Emergency shutdown 212

10.6.4 Reactor trips 212

10.6.5 Shutting down to a standby condition 212

xv
REFERENCES 213

APPENDICES 218

APPENDIX A: Mechanical Drawings for Distillation Column (DC) 2 219

APPENDIX B: Material Safety Data Sheet (MSDS) for 2- EthylHexanol 240

APPENDIX C: Simulation Graphs for Control Scheme of Oxo Reactor 248

APPENDIX D: Commissioning System File (Abridged) 254

APPENDIX E: Possible Problems, Analysis and Appropriate Action 267

xvi
 LIST OF TABLES

Table 1: Identification of 2- Ethylhexanol 1

Table 2: Physical and Chemical Properties of 2-Ethylhexanol 5

Table 3: Environmental Fate of 2-Ethylhexanol 6

Table 4: Miscellaneous Equipment Details and Functions 32

Table 5: Material Balance Data for Inputs and Outputs of OXO Reactor 49

Table 6: Material Balance Data for Inlets, Outputs and Off- Gases for GLS 1 52

Table 7: Material Balance Data for GLS- 2 54

Table 8: Overall Material Balance on Major Equipment (Dry Basis) 55

Table 9: Enthalpy of Formation of the Feed Stream 57

Table 10 Heat of Formation of Product Stream in KJ/mol at 298K 59

Table 11: Extracted Cp Data for Major Components 61

Table 12: Design Parameters of Some Major Plant Items 76

Table 13: Physical Parameters of Storage Tanks 80

Table 14: Material of Construction and the Operating Temperatures

and Pressure of the Major Items of Equipment 81

xvii
Table 15: Flow Properties of Distillation Column (DC) 2 92

Table 16: Chemical Engineering Design Properties of

Distillation Column (DC) 2 120

Table 17: Total Purchase Cost of Equipment Items (PCE) 172

Table 18A: Estimated Direct Costs (PCE) 174

Table 18B: Estimated Indirect Costs 174

xviii
 LIST OF FIGURES

Fig 1: Hydroformylation Mechanism 12

Fig 2: Unsimulated Process Flow Diagram (PFD) 26

Fig 3: Block Flow Diagram (BFD) 36

Fig 4: Hydrogenation Process 38

Fig 5: Aldol Condensation Process 40

Fig 6: Distillation Column (DC) 2 Process 41

Fig 7: Cracker Unit 43

Fig 8: Gas- Liquid Separator (GLS) 1 50

Fig 9: Distillation Column (DC) 2 84

Fig 10: x-y plot of Iso- butyraldehyde VLE Data 88

Fig 11: McCabe- Thiele Plot for Distillation Column (DC) 2 90

Fig 12: Dimensioned Sketch of Distillation Column (DC) 2 122

Fig 13: Dimensioned Sketch of Reboiler and Condenser 123

Fig 14: Sketch of the Second Distillation Column 139

Fig 15: Control Scheme for Hydroformylation Reactor 153

Fig 16: A Typical Response of a Valve 156

xix
Fig 17: Plot of Chemical Engineering Cost Index 163

Fig 18: The Plant Life- Cycle 183

xx
 ABBREVIATIONS

2-EH: 2-Ethylhexanol

BFD: Block Flow Diagram

CAS: Chemical Abstracts Service

COMAH: Control of Major Accident Hazards

COSHH: Control of Substances Hazardous to Health

CT: Cleaner Technology

DC: Distillation Column

DEHP: Di-(2-EthylHexyl) Phthalate

DOP: Di-Octyl Phthalate

ELD: Engineering Line Diagram

GLS: Gas Liquid Separator

HAZOP: Hazard Operability Studies

HSDB: Hazardous Substances Data Bank

HSE: Health, Safety and Environment

LMTD: Log Mean Temperature Difference

MATLAB: MATrix LABoratory

MSDS: Material Safety Data Sheet

NIST: National Institute of Standards and Technology

OECD: Organization for Economic Co-operation and Development

OPS: Operating Procedure Synthesis

P& ID: Piping and Instrumentation Diagram

xxi
PID: Proportional Integral Derivative

PFD: Process Flow Diagram

PPE: Personal Protective Equipment

PPM: Parts Per Million

PVC: polyvinyl chloride

RTECS: Registry of Toxic Effects of Chemical Substances

WHO- World Health Organization

xxii
 1

CHAPTER ONE

INTRODUCTION

1.1 Background

2-Ethylhexanol (2-EH) is a clear, colourless liquid with a characteristic odour, which has

been described as sweet and floral (Genium, 1999; WHO, 1993) and as intense and

unpleasant (HSDB, 2004; Verschueren, 2001). This compound occurs naturally in food

(e.g., corn, olive oil, tobacco, tea, rice, apricots, plums, apples, nectarines, tamarind grapes,

and blueberries) and is also used as a flavor additive in foods (WHO, 1993). In the

atmosphere, 2-ethylhexanol occurs as a vapor. This compound is combustible and will

react violently with oxidizing materials and strong acids. 2-Ethylhexanol is soluble in

organic solvents but only moderately soluble in water.

The chemical formula, structure, registry numbers, synonyms and trade names for 2-ethyl

hexanol are provided in Table 1 (NIST, 2003).

2-Ethylhexanol is formulated by petrochemical synthesis (WHO, 1993). 2-Ethylhexanol is

also a valuable intermediate in the chemical and petrochemical industry. It ranks after the

lighter alcohols (methanol to butanol) as the most important synthetic alcohol. The main

outlet for 2-ethylhexanol (2-EH) is the production of phthalate plasticizers, such as di-octyl

phthalate (DOP), which are used in the manufacture of polyvinyl chloride (PVC). The next

largest outlet for 2-EH is for the manufacture of the acrylate esters which are used in
 2

adhesives and surface-coating materials such as acrylic paints, in printing inks and as

impregnating agents.

According to Ashford’s Chemicals Dictionary (2011), the production of 2- Ethylhexanol

has recorded an average annual growth rate of 2.5% from 1986 – 2000. The future of 2-

ethylhexanol demand lies in the demand for phthalates such as DOP; the largest volume

phthalate ester; and is expected to remain flat or decline slightly due to competition from

other phthalates and environmental pressure. An issue for 2-EH producers is that DOP has

been dogged by health hazard and environmental concerns, and phthalates in general are

under pressure. On the positive side, there is increasing demand for other derivatives of 2-

EH, in particular 2-ethylhexyl acrylate.

 3

The industrial production of 2-ethylhexanol is by a three-step process involving the aldol

self-condensation of n-butyraldehyde followed by dehydration and hydrogenation. The n-

butyraldehyde was originally obtained from acetaldehyde via ethylene but this has been

superseded by the oxo process from propylene.

Today, nearly all 2-EH is produced by catalytic hydroformylation of propylene with

synthesis gas (carbon monoxide and hydrogen). The catalytic process now mostly uses

rhodium catalysts rather than the older cobalt hydro carbonyl catalysts.

The esters of 2-Ethylhexanol with dicarboxylic acids are excellent plasticisers for synthetic

resins and rubbers and include phthalates, adipates and sebacates .Its main application is as

a feedstock in the manufacture of low volatility esters, the most important of which is di-

(2-ethylhexyl) phthalate (DOP or DEHP). Other plasticizers that can be obtained from 2-

Ethylhexanol are the corresponding ester of adipic acid and para- hydroxylbenzoic acid.

2-Ethylhexanol is also used as a solvent and has a particular niche use in the formation of

lacquers and coatings when slow evaporation is desired. 2-Ethylhexanol is also an excellent

defoaming agent for use in the photographic, varnish, rubber latex, textile printing and

ceramic industries and can be used to advantage wherever foaming is undesirable.

2-Ethylhexanol is manufactured using the OXO process involving hydroformylation of

propylene to n-butyraldehyde followed by an Aldol condensation and reduction to produce

the ethyl hexanol.

 4

1.2 2- Ethylhexanol Properties and Uses

2-Ethylhexanol (2-EH) is a clear, colorless, mobile and neutral liquid with a characteristic

odor. It is miscible with most common organic solvents, but its miscibility with water is

very limited. It enters into the reactions that are typical for primary alcohols. For instance,

it readily forms esters with various acids. 2- Ethylhexanol is the oldest, best known and

most widely used of the synthetically made higher aliphatic alcohols.

1.2.1 Physical and chemical properties

The distinct physical and chemical properties of 2-ethylhexanol are summarized in Table 2.

1.2.2 Environmental fate

During commercial operations, 2-ethylhexanol is typically released to the environment as

an air emission or in wastewater. In the atmosphere, vapor phase 2-ethylhexanol is

degraded by photochemically produced hydroxyl radicals. In water, 2- ethylhexanol will

volatilize to air or undergo biodegradation, it is not expected to adsorb to sediments or

bioconcentrate in aquatic receptors. If released to soil 2- ethylhexanol will likely volatilize

from the surface or migrate to water, adsorption to soil is not significant.

A summary of the environmental fate and half-lives for 2-ethylhexanol is provided in Table

3 (HSDB, 2004). Appendix B gives the Material Safety Data Sheet (MSDS) for safe

handling of 2- Ethylhexanol.
 5

Table 2: Physical and Chemical Properties of 2-Ethylhexanol (NIST, 2003)

Property Value Reference

Molecular Weight 130.23g/mol Verschueren, 2001
Physical State Liquid Verschueren, 2001
o
Melting Point -76 C
Boiling Point 183.5 oC Verschueren, 2001
Specific gravity (liquid) 0.8344 at 20˚C Genium, 1999
Specific gravity (gas) (air=1) 4.49 Genium, 1999
Vapour Pressure 0.05 mmHg at 20˚C Verschueren, 2001
0.20 mmHg at 20˚C Lewis, 1997

Solubility Soluble in organic solvents Genium, 1999

Solubility in water 880 mg/l at 25˚C HSDB, 2004
1000 mg/l at 20˚C Verschueren, 2001

Henry's Law Constant 2.65 x10-5 atm-m3/mol Genium, 1999

Octanol water partition coefficient (log 2.81 Chemfate, 2003

Kow)
Organic carbon partition coefficient (Koc) 105 Genium, 1999
Viscosity 9.8 mPa.s at 20°C Lewis, 1997
Flash Point 81°C Genium, 1999
Explosive limits 0.88% to 9.7% Genium, 1999
231˚C
Autoignition Temperature 7.7 Genium, 1999
Dielectric constant at 20C
Critical Properties
Temperature 339.8°C
Pressure 2.76 MPa
Density 0.2636 g/cm3
Compressibility 0.2670
 6

Table 3: Environmental Fate of 2-Ethylhexanol2

System Fate Half- Life

Water Biodegradationand Estimated half-life in surface

volaltilization from surface. water (model river) due to

volatilization: 1.7days.

Soil Biodegradation,

volatilization and leaching to

Air groundwater. Atmospheric half-life of 1.2

Degradation via reaction days due to reaction with

with hydroxyl radicals. hydroxyl radicals.

1.2.3 Uses of 2- Ethylhexanol

In 1992, the prevailing worldwide use of 2-ethylhexanol was in the production of

plasticizers for PVC resins, hexyl esters and arylates (OECD, 1995). 2-Ethylhexanol is also

used as a solvent (dyes, resins, oils, antifoaming agents and nitrocellulose), a wetting agent

(organic synthesis, paint lacquer, baking finishes, inks, rubber, paper, lubricant,

photography and dry cleaning) and in textiles (finishing compounds and mercerizing

textiles) (Verschueren, 2001; Genium, 1999). In addition, the WHO reported an annual

production of 209 kilograms of 2-ethylhexanol for use as a flavor additive to food (WHO,

1993).

2
Source: HSDB, 2004.
 7

Examples of other applications for 2-Ethylhexanol are summarized below. The list is by no

means complete.

 Low-volatility solvent (e.g. for resins, waxes, animal fats, vegetable oils and

petroleum derivatives).

 Low-volatility ingredient in solvent blends for the dyestuffs and coatings industry.

 Flow and gloss improver in baking finishes.

 Feedstock for the manufacture of ethoxylates (products of reaction between 2-

ethylhexanol and ethylene oxide).

 Feedstock in the manufacture of herbicides.

 Feedstock in the manufacture of extractants (e.g. for heavy metals) – In the

production of the corresponding diester of maleic acid for use as a starting material

for surfactants.

 Feedstock in the manufacture of 2-ethylhexyl sulphate which is used as a surfactant

for electrolytes.

 In the production of 2-ethylhexyl esters of trialkyl phosphites which can serve as a

thermal stabilizer and antioxidant in plastics.

 In the manufacture of particularly pure grades of DOP which act as polychlorinated

biphenyl substitutes in heavy-duty capacitors.

 In antifoams for almost all aqueous systems (e. g. in the textile and paper

industries).
 8

CHAPTER TWO

LITERATURE REVIEW

2.1 Choice of Synthesis Route

The economics of the various processes for the manufacture of 2- Ethylhexanol are

strongly dependent on the price of the feedstock used. The industrially significant synthetic

pathways are the Acetaldehyde route, Oxo route, Aldox process and the Shell Variant

process. Davy Process Technology (formerly Kvaerner) and Dow (Union Carbide) jointly

have led the development of newer catalytic technologies and have developed a phosphite

ligand modified rhodium catalyst. The two companies have also dominated the licensing of

2-EH process technology. Shell has developed and operates a one-step process that

converts propylene directly to butanol, iso-butanol and 2-ethylhexanol (icis.com, 2007).

Discussed below are various ways of producing acetaldehyde from different source of raw

material.

2.1.1 Acetaldehyde route

The acetaldehyde route starts from ethylene and operates at near atmosphere pressure.

Ethylene is first oxidized to acetaldehyde, which is then converted to crotonaldehyde via

aldol reaction & hydrogenated to n-butyraldehyde.

 9

2.1.2 Aldox process

Aldox process is a case in which co-catalysts are added to the actual Oxo catalyst enabling

aldolization to occur in the same phase. The present invention provides a process for

producing 2-ethylhexanol having a reduced concentration of 2-ethyl-4-methyl pentanol. It

may be practiced in its most basic form as a distillation. It may also be practiced as part of

a multi-stage continuous process. In either form it begins with a feed stream comprising n-

butyraldehyde containing as a contaminant, isobutyraldehyde, complexes of

isobutyraldehyde, oligomers of isobutyraldehyde and mixtures thereof, to which is added or

introduced, an amount of water effective to hydrolyze the oligomeric contaminants to the

monomeric form of isobutyraldehyde during distillation. The water containing aldehyde

mixture is introduced to a distillation zone with a residence time and at a temperature

sufficient to hydrolyze the oligomeric contaminants to and then distill substantially all of

the isobutyraldehyde overhead. In the multi-stage process, the distilled n-butyraldehyde is

then subjected to an alkali-catalyzed aldol condensation reaction to produce 2-ethylhex-2-

enal. In a third stage, the 2-ethylhex-2-enal is hydrogenated with a catalyst under

temperature and pressure conditions conducive to hydrogenation to produce 2-

ethylhexanol.

2.1.3 Shell process

In the shell process a complex (ligand-modified Hydroformylation catalyst)

HCO(CO)3(PR3)3 – is employed. This permits operation at lower pressure and higher

selectivity i.e. at a higher n/i ratio. However, the reaction velocity is lower & part of the

propylene is converted to propane. The shell process represents an improvement in a

 10

process for the manufacture of 2-ethylhexanol wherein n-butyraldehyde is subjected to

aldol condensation, the resultant aldol condensation product is catalytically hydrogenated

in a hydrogenation stage and the hydrogenation product is subjected to two separate

multiple stage distillations to separate, in the first case the first runnings, a fraction

containing the main amount of 2-ethylhexanol, and the residue. In the second case this

residue is separated into a 2-ethylhexanol fraction and a distillation residue, the

improvement residing in cracking the distillation residue by heating the same at 200 to

250° C whereby to obtain cracked products comprising n-butanal, 2-ethylhexenal, 2-

ethylhexanal, and/or 2-ethylhexanol together with non-cracked higher boiling substances.

The cracked products are separated from the non-cracked products and the cracked

products are recycled to the hydrogenation stage.

2.1.4 Oxo process

Hydroformylation, also known as oxo synthesis or oxo process, is an important

homogeneously catalyzed industrial process for the production of aldehydes from alkenes.

This process has undergone continuous growth since its invention in 1938; this chemical

reaction entails the addition of a formyl group (CHO) and a hydrogen atom to a carbon-

carbon double bond. The process typically is accomplished by treatment of an alkene with

high pressures (between 10 to 100 atmospheres) of carbon monoxide and hydrogen at

temperatures between 40 and 200 °C (Ojima et al., 2000). Transition metal catalysts such

as Cobalt carbonyl are required.

 11

The reaction begins with the generation of coordinatively unsaturated metal hydrido

carbonyl complex such as HCo(CO)3. Such species bind alkenes, and the resulting complex

undergoes a migratory insertion reaction to form an alkyl complex, for subsequent

conversion to aldehyde (Fig 1).

A key consideration of hydroformylation is the "normal" versus "iso" selectivity. For

example, the hydroformylation of propylene as given in this report can afford two isomeric

products, n- butyraldehyde or iso- butyraldehyde.

H2 + CO + CH3CH=CH2 → CH3CH2CH2CHO (normal)

Versus

H2 + CO + CH3CH=CH2 → (CH3)2CHCHO (Iso)

These isomers result from the differing ways of inserting the alkene into the M-H bond. Of

course, both products are not equally desirable. Much research has been dedicated to the

quest for catalyst that favored the normal isomer.

A usually desired consecutive reaction is the partial hydrogenation of the aldehydes to

alcohols as it occurred in this particular process considered. Higher temperatures and

hydrogen partial pressures favor the hydrogenation of the resulting aldehyde(s) to the

alcohol(s). For the reaction mechanism it is believed that the aldehyde initially forms a Co-

π-complex with the catalyst.

This is rearranged to the alkoxide complex and by subsequent oxidative addition of

hydrogen the alcohol is eliminated and the starting complex is formed.

 12

Fig 1: Hydroformylation Mechanism (LSU, 2001)

 13

For the Aldol condensation process, the aldolization reactor may be a mixing pump, a

packed column or a stirring vessel. Local overheating in the reaction mixture must be

avoided since this may cause secondary reactions & thus decrease yields. Subsequent

hydrogenation of the 2- Ethylhexanal produced from the aldolization process in the

presence of a Raney Catalyst gives the 2- Ethylhexanol desired.

The oxo process represents the most important synthetic route accounting for over 95% of

2-EH production and it is based on propylene which after initial Hydroformylation is

converted into an Oxo crude product. The crude Oxo product is a mixture of valuable

products of propylene hydroformylation (n - and iso–butyraldehyde) along with the

byproducts (n– and iso–7 butanol) and the heavy ends. The individual components of the

mixture can be obtained after distillation.

H2 + CO + CH3CH=CH2 → CH3CH2CH2CHO

n – Butyraldehyde is converted into butyraldol via an alkali catalyzed reaction and then

crotonized to 2-Ethylhexenel. Thereafter, 2-Ethylhexenal is either partially hydrogenated to

2-ethylhexanal or undergoes total hydrogenation to 2-EH. The n-component mixture of n-

and iso – butyraldehyde can be selectively converted into 2- Ethylhexenal and then further

processed to 2-EH. However, due to the presence of isobutyraldehyde and the unavoidable

formation of isomeric n/iso and iso/iso aldols (or C8 diols), the quality of the resulting 2-

EH is inferior to that of the product obtained directly from n-butyraldehyde.

 14

Basically similar reservations pertaining to the quality of the resulting 2-EH also apply to

the processing of the heavy ends of the Oxo synthesis which also yields 2-EH after

additional hydrogenation. However, one drawback is that in molar terms only 2/3 of the

butanol feedstock is converted into 2-EH, the remaining third resulting as sodium

butanoate.

2.2 Specifications, Analytical, and Test Methods

Commercial 2- Ethylhexanol has the following typical specifications: assay, 99.5% min;

color, water-white; acidity, 0.015% max (acetic acid); specific gravity, 0.8344 at 200C;

boiling point, 184.6 at 760 mmHg. Anhydrous 2-ethylhexanol does not attack common

metals. Tanks constructed from normal steel are reliable for storing 2-ethylhexanol. If

severe demands are imposed on the quality of the product, the tanks should be constructed

of stainless steel or aluminum.

Moisture in the atmosphere must be excluded by storing the product under a blanket of

inert gas or by installing a dehumidifier. Drums should be kept tightly closed in a well-

ventilated place. Precautions to be observed in the handling of acetaldehyde have been

published by the manufacturing chemists association. (Always refer to the Material Safety

Data Sheet (MSDS) for detailed information on handling and disposal).

 15

Analytical methods based on many of the reactions common to alcohols and alkyl- alcohols

have been developed for the determination of acetaldehyde.

2.3 Process Selection

Here, hydroformylation (oxo) route is selected for the production of 2- Ethylhexanol. As a

result of the fact that a combination of vacuum and pressure operation has made it possible

for the reaction to be carried at a lower temperature and without excess propylene and

synthesis gas, also the hydrogenation of the 2-ethylhexanol from 2- Ethylhexanal can be

done without the use of steam for heating or refrigerating for condensing or absorption

below usual cooling water temperature. In view of the above, the chosen process has the

following advantages:
 16

a) It eliminates the disadvantages of recycling excess propylene.

b) The reaction has less unfavorable side reactions and hence higher yields due

to the low reaction temperature.

c) The reaction heat is removed and used by a combination of vacuum

evaporation and high pressure rectification.

d) No refrigeration is required in the manufacturing operations; and cooling

water of relatively high temperature may be used in all coolers and

condensers.

e) The mechanical and operating losses of 2- EH are low, owing to the simple

process flow-sheet, lack of recycling, and the few units. The process is

simple and relatively inexpensive

The oxo process presents no significant pollution problems. All byproducts –off –gas, low

boiling and high boiling liquids – can be easily used as fuel to recover their calorific value.

The separation of the cobalt in the catalyst system has been improved so much in the recent

years that the catalyst loss in the effluents is considerably reduced. The wastewater can be

treated without any difficulties to meet requirements of local authorities.

It also has some possible disadvantages: the synthesis gas may contain several percent

methane, which act as an inert in the reactor. Traces of water introduced with the synthesis

gas are not harmful. However, Impurities such as hydrogen sulfide and triethylamine

prevent reaction with the active cobalt complex to form catalytically inactive complexes.

Also, Oxygen must be excluded from the system, during the start up phase when the active

catalyst concentration is being established. Oxygen has been shown to inhibit cobalt
 17

hydrocarbonyl formation, but once the system is operating, concentration up to 2% can be

tolerated; CO2 acts in the same manner as oxygen, with concentration up to 4%

permissible. Polymer grade (99+%) pure propylene is needed to be fed vaporized, and

designing for propylene conversions of greater than 95% per pass is required to minimize

propylene losses in the blow down vent stream. There were some problems in mechanical

design and construction materials to withstand corrosion and erosion, but these have been

solved in the several years of operation.

The equations of the reactions that will take place in the selected process are:

H2 + CO + CH3CH=CH2 → CH3CH2CH2CHO ΔH°298=-135.5 kJ/mol

2(H 3 C-CH 2 -CH 2 -CHO) 2%

NaOH
 H 3 C-CH 2 -CH 2 - CH=C(C 2 H 5 )-CHO  H 2 O

ΔH°298=-262.0 kJ/mol

Ni
H 3 C  CH 2  CH 2  CH  C(C 2 H 5 )  CHO  2H 2  H 3 C  (CH 2 ) 3  CH(C 2 H 5 )  CH 2 OH

ΔH°298=-433.0 kJ/mol
 18

2.4 Process Description

2.4.1 Problem statement

Design a plant to produce 72,000 metric tons (tonnes)/year of 2-ethylhexanol from

propylene and synthesis gas, assuming an operating period of 8,000 hours on stream.

2.4.2 The process

The objective of this design work is to prepare a complete plant design for the production

of 72000 tonnes per year of 2-ethylhexanol using propylene and synthesis gas, choosing the

oxo route and assuming a production run- time of 8000 hours on stream. The first stage of

the process is a Hydroformylation (oxo) reaction from which the main product is n-

butyraldehyde. The feeds to this reactor are synthesis gas (CO/H2 mixture) and propylene

in the molar ratio 2:1, and the recycled products of iso- butyraldehyde cracking. The

reactor operates at 130oC and 350 bar, using cobalt carbonyl as catalyst in solution. The

main reaction products are n- and iso-butyraldehyde in the ratio of 4:1, the former being the

required product for subsequent conversion to 2-ethylhexanol. In addition, 3 per cent of the

propylene feed is converted to propane whilst some does not react. Within the reactor,

however, 6 per cent of the n-butyraldehyde product is reduced to n- butanol, 4 per cent of

the iso-butyraldehyde product is reduced to iso-butanol, and other reactions occur to a

small extent yielding high molecular weight compounds (heavy ends) to the extent of 1 per

cent by weight of the butyraldehyde or butanol mixture at the reactor exit.

 19

The reactor is followed by a gas-liquid separator operating at 30 bar from which the liquid

phase is heated with steam to decompose the catalyst for recovery of cobalt by filtration. A

second gas-liquid separator operating at atmospheric pressure subsequently yields a liquid

phase of aldehyde, alcohols, heavy ends and water, which is free from propane, propylene,

carbon monoxide and hydrogen.

This mixture then passes to a (first) distillation column which gives a top product of mixed

butyraldehyde(s), followed by a second column which separates the two butyraldehydes

into an iso-butyraldehyde stream containing 1.3 per cent mole n-butyraldehyde and an n-

butyraldehyde stream containing 1.2 per cent mole iso-butyraldehyde.

A cracker converts iso-butyraldehyde at a pass yield of 80 per cent back to propylene,

carbon monoxide and hydrogen by passage over a catalyst with steam. After separation of

the water and un-reacted iso-butyraldehyde, the cracked gas is recycled to the

hydroformylation reactor. The iso-butyraldehyde is recycled to the cracker inlet. The

operating conditions of the cracker are 275oC and 1 bar.

The n-butyraldehyde is treated with a 2 per cent w/w aqueous sodium hydroxide and

undergoes an Aldol condensation at conversion efficiency of 90 per cent. The product of

this reaction, 2-ethylhexanal, is separated and then reduced to 2-ethylhexanol by hydrogen

in the presence of a Raney nickel catalyst with a 99 per cent conversion rate. In subsequent

stages of the process (details of which are not required), 99.8 per cent of the 2-ethylhexanol

is recovered at a purity of 99 per cent by weight.

 20

2.4.3 Feed specifications

(i) Propylene feed: 93% propylene, balance propane.

(ii) Synthesis gas: from heavy fuel oil, after removal of sulfur compounds and

carbon dioxide: H2 48.6%; CO 49.5%; CH4 0.4%; N2 1.5%.

2.4.4 Utilities

(i) Dry saturated steam at 35 bar.

(ii) Cooling water at 25°C.

(iii) 2% w/w aqueous sodium hydroxide solution.

(iv) Hydrogen gas: H2 98.8%; CH4 1.2%.

2.5 Scope of the Design Work

2.5.1 Process design

a) To prepare a material balance for the complete process.

b) To prepare a process diagram for the plant showing the major items of

equipment. Indicate the materials of construction and the operating

temperatures and pressures.

c) To prepare an equipment schedule, listing the main plant items with their

sizes, throughput, operating conditions, materials for construction, and

services required.

d) To prepare energy balances for the hydroformylation reactor and for the iso

butyraldehyde cracking reactor.

 21

2.5.2 Chemical engineering design

a) To prepare a chemical engineering design of the second distillation unit, i.e.,

for the separation of n- and iso butyraldehyde.

b) To make dimensioned sketches of the column, the reboiler, and the

condenser.

2.5.3 Mechanical design

a) To prepare a mechanical design with sketches suitable for submission to a

drawing office of the n- and iso butyraldehyde distillation column.

2.5.4 Control system

a) To prepare a control scheme to ensure safe operation of the

hydroformylation reactor

2.5.5 Cost estimate

a) To prepare a cost estimate of the equipment needed for the plant and hence

the installed plant cost assuming Port Harcourt as the preferred location.
 22

2.6 Data Supplied

2.6.1 Chemical reactions

1. Hydrogenation of Propylene to Propane

H 3 C - CH = CH 2 + H 2  H 3 C - CH 2 - CH 3 ΔH°298=-129.5 kJ/mol

2. Reaction of Propylene with Synthesis gas

H2 + CO + CH3CH=CH2 → CH3CH2CH2CHO (normal)

ΔH°298=-135.5kJ/mol

or → (CH3)2CHCHO (Iso) ΔH°298=-141.5 kJ/mol

3. Reduction of Butyraldehyde to Butanol

H3C-CH2-CH2-CHO + H2 → H3C-CH2-CH2-CH2OH ΔH°298=-64.8 kJ/mol

4. Reaction of Cobalt with Carbon Monoxide

2Co + 8CO → Co2(CO)8 ΔH°298=-462.0 kJ/mol

5. Aldol Condensation of n-butyraldehde

2H3C-CH2-CH2-CHO → H3C-CH2-CH2- CH=C(C2H5)-CHO + H 2O

ΔH°298=-262.0 kJ/mol

6. Hydrogenation of 2-Ethyl Hexenal to 2-Ethyl Hexanol

Ni
H 3 C  CH 2  CH 2  CH  C(C 2 H 5 )  CHO  2H 2  H 3 C  (CH 2 ) 3  CH(C 2 H 5 )  CH 2 OH

ΔH°298=-433.0 kJ/mol
 23

2.6.2 Boiling points at 1 bar

Liquid Boiling Point (°C)

Propylene -47.7

Propane -42.1

n- Butyraldehyde 75.5

Iso butyraldehyde 64.5

n- Butanol 117.0

Iso butanol 108.0

2- Ethylhexanol 184.7

2.6.3 Solubilities of gases at 30 Bar in the liquid phase of the first gas-liquid

separator

Gas Solubility (kg dissolved per kg liquid) * 10-3

H2 0.08

CO 0.53

Propylene 7.5

Propane 7.5
 24

2.6.4 Vapor-liquid equilibrium of the butyraldehydes at 1 atm (Wojtasinski, 1963)

T°C x y

73.94 0.1 0.128

72.69 0.2 0.264

71.40 0.3 0.381

70.24 0.4 0.490

69.04 0.5 0.589

68.08 0.6 0.686

67.07 0.7 0.773

65.96 0.8 0.846

64.95 0.9 0.927

where x and y are the mol fractions of the more volatile component (isobutyraldehyde) in

the liquid and vapor phases respectively.

 25

CHAPTER THREE

PROPOSAL

3.1 Process Description

From the narrative of the design problem given in Section 2.4.2, a graphical depiction of

the design process was constructed in an unsimulated Process Flow Diagram (PFD) using

AspenTech HYSYS 3.2 2003®, as given in Fig 2.

The various processes occurring along the reaction path are highlighted under the

respective equipment in the ensuing sections.

3.1.1 Hydroformylation reactor

The feed to the reactor consists of propylene and Synthesis Gas. The propylene feed is

made up of fresh propylene feed (1) and recycled propylene (24) from the Cracker, and

stripped propylene from GLS 2(15). The Synthesis gas feed (2) is first used to strip

unreacted propylene, CO and H2 present in GLS-2 before it is fed to the Hydroformylation

Reactor. A fraction of the synthesis gas used for stripping is purged (16) to reduce the

concentration of inerts such as CH4, N2 and Propane. The Hydroformylation Reactor is run

at 130oC and 350 bar using Cobalt carbonyl as catalyst in solution. The Cobalt (4) is fed

into the reactor already in solution. In the reactor, the Cobalt reacts with the Carbonyl to

form Dicobalt octacarbonyl Co2(CO)8 according to the reaction below:

2Co + 8CO Co2(CO)8

 26

OGUNGBENRO
Adetola E
CHE/2007/083
October- 2- 2012

30

Hydrogenator
29*
14b C
15
12
MIX-103
16
13 24
32
22

3 23
5 11 Mixer Cracker
Mixer 4
25
18 29b
1 10 28
20
6 7 Separator
Oxo R
Compressor VLV-100 12b
Reactor L L
C Mixer2 17 Aldol
RCY-1
Cooler
2 Reactor
8 9 12* C
E-100 DC 29
4 2 P-100
19
GLS-1 VLV-101 GLS DC
2 1 21
26
27a
17* Mixer 21b
14 3
27
Filter
R
RCY-2

Fig 2: Unsimulated Process Flow Diagram

Flowsheet: Case (Main)

 27

Hydro (di) Cobalt (tetra) Carbonyl HCo(CO)4 is generally believed to be the active catalyst

form or at least the precursor to the active catalyst form which also may be HCo(CO)3. The

Higher the Hydrogen partial pressure in the Hydroformylation Reactor and the higher the

Temperature, the greater the concentration of hydro cobalt Carbonyl and hence the greater

the Reaction Rate. Equilibrium is believed to establish itself between 2 carbonyls

2HCo (CO)4 Co2(CO)8 + H2

Dicobaltoctacarbonyl, under influence of higher temperature and/or lower partial pressures

of carbon monoxide, may split off carbon monoxide and form cobalt cluster forms that

gradually contain more cobalt and less carbonyl functions, and which are less and less

soluble in the reaction medium, up to the point where the cobalt compounds comes out of

solution in forms that contain little carbon monoxide and approach the state of cobalt metal

or are metallic. This phenomenon is referred to as “cobalt plating”. These clusters and

lower carbonyl containing forms of cobalt are inactive for the hydroformylation reaction. It

is well known that at a given temperature and cobalt concentration, a certain partial

pressure of carbon monoxide is required in order to maintain the stability of the cobalt

carbonyls and to prevent the cobalt to come out of solution and deposit inside the

equipment. Consequently, the concentration and the stability of the active

hydroformylation catalyst is, under constant operating conditions, affected by the gas

composition, e.g. the levels of inerts and those of H2 and carbon monoxide.

For this reason, it is desired to maintain sufficient concentration of Hydrogen in the reactor

to prevent plating out of the Cobalt. This also ensures that the Cobalt is in its active hydro
 28

cobalt carbonyl form. Typically, a ratio of Hydrogen to CO of 1.7:1 is preferred in the

reactor. This is the reason for recycling unreacted hydrogen (32) from the Hydrogenation

reactor into the (MIX-103) to the Hydroformylation Reactor. The concentration of Cobalt

in the Hydroformylation Reactor is 1 weight %.

3.1.2 Gas liquid separator 1 (GLS-1)

Cobalt plating takes place in GLS-1 by passing saturated steam into it. The steam raises the

temperature of the solution sufficiently for most of the carbonyl to vaporize and plate out

the Cobalt Metal. The GLS is used to separate the aqueous phase (cobalt + Water) from the

organic phase (Butanals & Butanols) since they are immiscible (10). The aqueous phase is

subsequently passed into a filter where some of the water is removed (14) and cobalt +

water (4) are recycled back into the Reactor. Water in the Reactor should not be more than

1.5 weight% of the Propylene feed. GLS-1 operates at 160oC and 30 bar.

3.1.3 Gas liquid separator 2 (GLS- 2)

The organic phase (12) from GLS-1 is passed through a valve to drop its Pressure to 1 bar;

then cooled to 55oC by a cooler. The temperature and pressure are chosen so as to ensure

that the propylene (B.P -47.4oC) is in gaseous form and the Butanols (108-117oC) and

Butyraldehydes (64.5 – 75.5oC). Fresh synthesis gas is used to strip out propylene, CO and

H2

.
 29

3.1.4 Distillation column 1 (DC 1)

The feed to DC 1(17) is first preheated using a Heat Exchanger (Hx-1) to a temperature of

72.55oC.The mixture (17*) is passed into the Distillation column which gives a top product

of mixed butyraldehydes and bottoms containing mixed butanols and heavy ends. The top

product is fed into a second distillation unit which separates the mixture into iso- and n-

butyraldehyde.

3.1.5 Distillation column 2 (DC 2)

The top product (20) from DC 2 is a stream of 98.7% iso-butyraldehyde and 1.3% n-

butyraldehyde at a temperature of 60oC. The bottoms (21) is a stream of 98.8% n-

butyraldehyde and 1.2% iso-butyraldehyde at 70oC.

3.1.6 Cracker unit

The Cracker converts iso-butyraldehyde at a pass yield of 80% back to Propylene, CO and

H2 by passage over a catalyst bed with steam. A recycle stream is connected to increase the

conversion to initial reactants. All the n-butyraldehyde is converted since it is in minute

quantity and also more reactive during Cracking. The Cracker operates at 275oC and 1Bar.

The phase separator separates out the Propylene, CO, H2 gas, the liquid phase (water) and

the organic phase (un- reacted butyraldehydes) which is recycled into the Cracker.
 30

3.1.7 Aldol reactor

The n-butyraldehyde is treated with a 2% w/w aqueous NaOH and undergoes and Aldol

condensation at a conversion efficiency of 90%. The Aldol Reactor operates at 115oC, 3

Bar.

The iso-butyraldehyde passes through the Aldol reactor unreacted. The butyraldehydes exit

the reactor as vapor. The 3-Phase separator separates out a liquid phase of aqueous NaOH,

organic phase of 2-Ethylhexanal and gaseous phase of butyraldehydes, a percentage of

which is purged before it is recycled back into the Aldol Reactor (25) to prevent

accumulation of iso-butyraldehyde in the reactor.

3.1.8 Hydrogenation reactor

The aqueous phase (29) is pumped into the Hydrogenation Reactor at 50bar (29*). In

hydrogenation processes, heating of the ingoing materials is best accomplished by heat

exchange with the outgoing materials and adding additional heat by means of high-pressure

pipe coils. A pipe coil is the only convenient and efficient method of heating, for the

reactor is usually so large that heating it is very difficult. It is usually better practice to add

all the heat needed to the materials before they enter the reactor and then simply have the

reactor properly insulated thermally. Hydrogenation reactions are usually exothermic, so

that once the process is started; the problem may be one of heat removal. This is

accomplished by allowing the heat of reaction to flow into the ingoing materials by heat

exchange in the reactor, or, if it is still in excess, by recycling and cooling in heat

exchangers the proper portion of the material to maintain the desired temperature.
 31

The Nickel Catalyst is usually activated by heating it in a stream of Hydrogen. The

operation is usually with a stoichiometric excess of hydrogen which is recycled back into

the Hydroformylation Reactor as stated above (32). The operating conditions of the Reactor

are 150oC and 50 bar. The Product of this reaction 2-Ethylhexanol is recovered at a purity

of 99% by weight via distillation.

3.2 Miscellaneous Equipment

A number of equipment is fixed in between the resulting streams, in order to allow

the resulting stream approach a desired operating condition in the next stage. These include

mixers, valves, compressors, coolers, recycles etc. Table 4 gives a breakdown of these

miscellaneous streams, details and functions and location of applications.

 32

Table 4: Miscellaneous Equipment Details and Functions

Miscellaneous Function Number of Units Location

Equipment Used

Recycles To recover streams 2 Cracker Unit

that would otherwise Aldol Reactor

have gone to waste

Compressors To increase pressure 1 Oxo Reactor

of a gaseous stream

to attain a reactor pre-

condition

Heat Exchange To regulate 2 GLS 2

equipment temperature of a DC 1

process stream by

coolers (reduce) or

heaters(increase)

Separators To classify 1 Hydrogenation

components of a Reactor

stream into desired

component, and

collectables/purged

streams
 33

Table 4: Miscellaneous Equipment Details and Functions (Cont’d)

Miscellaneous Function Number of Units Location

Equipment Used

Filter To separate 1 GLS- 1

constituents of a

process stream;

particularly used for

cobalt catalyst

filtration

Mixers To combine various 5 Oxo Reactor

streams from GLS-1

processes into a single Cracker

stream; achieves no Aldol Reactor

chemical changes Combined Recycle

Stream

Valves Used a control 2 GLS-1

instrument, to regulate GLS- 2

pressure of flowing

streams

Pump Same working 1 Hydrogenator

principle as

compressors; except

works for liquid

 34

CHAPTER FOUR

PROCESS DESIGN BALANCES

Oguntoye (2008) considered a similar design process for the production of 40000 tons/year

of 2- Ethylhexanol using the OXO route. He achieved a throughput of 38.001 kmol/hr 2-

Ethylhexanol (at 99% purity) with a feed of 8535.89 kg/hr of propylene and synthesis gas.

However, it is desired in this report to achieve unit process optimization by deliberate

recycle of input feeds and purging of tie- materials and other miscellaneous streams.

Important modifications achieved are in the Aldol Condenser & Cracker processes which

have limited efficiencies of 90 & 80% respectively (Section 2.4.2).

In preparing this report, two methods have been identified as most feasible in arriving at

the material balances for the multi- integrated units of the plant. A choice is the selection of

a basis for propylene feed, which will include that obtained from cracked iso-

butyraldehyde, stripped propylene from the 2nd Gas- Liquid Separator, and fresh

propylene(with 7% propane). Henceforth, stoichiometric proportions of synthesis gas will

give the various products to be obtained at the end of the hydroformylation process. Ratios

of products obtained, deductible fractions of side reactions and performance efficiencies of

reactors can then be considered along the path of reactions to arrive at a particular 2-

Ethylhexanol throughput for the chosen propylene basis. Scaled ratios of given throughput

(72,000tons/year) to obtained throughput will then provide the amount of propylene feed
 35

that would have given the desired throughput. The process calculations are then repeated to

determine intervening values of product species and accuracy check.

An alternative method which was adopted for compilation of the material balance given in

this report involved starting from the actual throughput given (i.e. 72000tons/year),

establishing stoichiometric ratios of reactions involving 2- EH in a reverse path (back) to

the oxo reactor. The second method was preferred as it assures no scaling marginal errors

were involved, as much as it guarantees accurate results provided acute comprehension of

reactions are known.

In computing the energy balance for the cracker and oxo reactor, basic assumptions were

made on the change of temperature from inlet through reference to the exit temperature.

Heat losses to the environment and those due to mixing were considered negligible, and the

mass flow flowrate of utilities (cooling water and steam) were calculated from heat balance

equations.

4.1 Material Balance

A simplified Block Flow Diagram (BFD) of the Process Flow Diagram (Fig 2) is as

presented in Fig 3. The material balance will be computed based on the BFD in Fig 3.
 Recycled Streams
MIXER 36

Stream of CO, alkene & H2 Purge

Purge 1 Purge 2
Dry Steam 35
Stream of alkene
bar

FreshC3 Oxo Reactor Mixer Valve GLS 1 Cooler GLS 2

DC 1
Synthesis 130°C,,350
130°C 350 30 bar 1 bar
bar
Gas

Filter

Recycle Collect Alcohols, heavy ends & water

Cobalt

Major iso- stream

CRACKER (80%)

275°C 1 bar
Recycle

DC 2 Mixed Aldehydes

Excess H2 2% w/w NaOH

ALDOL REACTOR
SEPARA
2- EH (90%) Major n- stream
HYDROG TOR
ENATOR

H2 Fig 3: Block Flow Diagram (BFD)

 37

Throughput= 72,000 tons/year

Runtime (i.e. total number of operating hours of the plant in a year) = 8,000 hours

$ Convert throughput to kilograms/ hour, kg/hr)

72,000 ton 1yr 1000kg

  
Throughput= 1 yr 8000hr 1 ton
 9000kg / hr

$ Convert to kmol/hr given that the Molecular Mass of 2-Ethylhexanol is 130.23kg/kmol

9000
Throughput=  69.109kmols/ hr
130.23

From problem statement, 99.8% of 2-Ethylhexanol produced is recovered. Hence,

69.109kmols / hr represents this recovered amount.

69.109
Actual Amount produced=  69.247kmols/ hr
0.998

At a purity of 99% by weight, amount of 2- Ethylhexanol realized =

0.99 * 69.247 = 68.555 kmols / hr

 38

4.1.1 Hydrogenation

Ni
H 3C  CH 2  CH 2  CH  C (C 2 H 5 )  CHO  2 H 2  H 3C  (CH 2 ) 3  CH (C 2 H 5 )  CH 2 OH
(Rxn 1) 2- Ethylhexenal 2- Ethylhexanol

Ni
Catalyst
2 Ethylhexenal 2  Ethylhexan ol
             
99%
Convers
ion

H2

Fig 4: Hydrogenation Process

From (Rxn 1), 69.247 kmols/hr of 2- Ethylhexanol had been produced at stoichiometric

ratio 1:1 from 2-Ethylhexenal at 99% conversion.

Amount of 2- Ethylhexenal that produced 69.247 kmol/hr of 2- Ethylhexanol=

69.247
= 69.946 kmol / hr
0.99

From (Rxn 1); 1 mole of 2- Ethylhexenal requires 2 moles of hydrogen (H2). However,

69.946 kmoles/hr of the aldehyde was sent in but 69.247 kmoles/hr was converted.

69.247 kmoles/hr of 2- Ethylhexenal will require 2  69.247  138.494kmoles/ hr of H2

 39

NOTE: (Let Hydrogen be supplied in 100% excess and excess is recycled to

hydroformylation (oxo) reactor i.e. 138.494 kmoles/hr H2 was recycled into OXO reactor.

Hence, only pure hydrogen is sent back into OXO reactor.)

However, H2 stream contains 98.8% H2 and 1.2% CH4.

Amount of H2 actually sent in = (138.494 + 138.494)/ 0.988= 280.3522kmoles/hr

Amount of CH4 contained in H2 stream = 0.012 * 280.3522= 3.3642kmoles/hr

Excess 2- Ethylhexenal = Amount Supplied- Amount Converted to 2- EH

= 69.946-69.247

= 0.699kmols/hr (negligible, purged)

4.1.2 Aldol reactor

2( H 3 C-CH 2 -CH 2 -CHO) 2%NaOH

 H 3 C-CH 2 -CH 2 - CH=C(C 2 H 5 )-CHO  H 2 O

(Rxn 2) n-butyraldehyde 2- Ethylhexenal Water

From (Rxn 2), 2 moles of n- butyraldehyde produced 1 mole of 2- Ethylhexenal and 1 mole

of water at 90% conversion efficiency of reactor.

NOTE: A conversion efficiency of 90% wastes a lot of the n- butyraldehyde; hence a

recycle process is proposed.

 40

2% w/w Aq.
NaOH

K
F1 ALDOL REACTOR

90% CONVERSION
EFFICIENCY

Recycle, R1

Fig 5: Aldol Condensation Process

F1 is a stream on n- butyraldehyde for (bottoms) Distillation Column 2; K is 2-

Ethylhexenal.

By relationship provided,

R1= 0.1F1

From stoichiometry & completing a material balance on butyraldehyde,

0.9 (1.1 F1) = 2 * 69.946

F1= 141.305 kmoles/hr

Number of moles of H2O formed = 69.946 kmoles/hr

4.1.3 Distillation column (DC) 2

Let butyraldehyde/butanol feed obtained as product of hydroformylation= P kmoles/hr

Before conversion of aldehydes to alcohols;

 41

n- butyraldehyde= 0.8P; iso- butyraldehyde= 0.2P

After conversion to alcohols; 4% of iso- butyraldehyde goes to iso- butanol while 6% of n-

butyraldehyde goes to n- butanol.

n- butyraldehyde= 0.94 * 0.8P = 0.752P

iso- butyraldehyde= 0.96 * 0.2P = 0.192P

Feed to Distillation Column 2 is mixed aldehydes after alcohols have been removed by

DC1, & others (propane, propylene, CO & H2) have been removed by GLS 2.

Therefore; Feed to Distillation Column 2 (DC2)

FDC2 = 0.752P + 0.192P

= 0.944P

D, xD

FDC2 = D+W

FDC2 ZF= DxD + W xW

F, ZF
DC2
0.192P
ZF = (w.r.t to iso- butyraldehyde)
0.944P

ZF = 0.203

W,xw

Fig 6: Distillation Column

(DC) 2 Process
 42

W = Bottom Product is stream of n- butyraldehyde

F1 141.305
=   143.02kmols / hr
0.988 0.988

0.944 P * 0.203  (0.944 P  143.02) * 0.987  (143.02 * 0.012)

0.1916 P  0.931728P  141.16674  1.7164

 0.740128 P  139.445

P  188.41kmols / hr

P represents the total amount of product from OXO reactor.

F  0.944 P  0.944 * 188.41

F  177.86kmoles / hr

D  F  W  177.86  143.02

D  34.835kmols / hr

TOTAL BALANCE AROUND DC2

In Feed, there is 0.752P (n- butyraldehyde) and 0.192P (iso- butyraldehyde)

0.752P= 141.684kmols/hr n- butyraldehyde

0.192P= 36.175 kmols/hr iso- butyraldehyde

In Top Product (D)

iso- butyraldehyde= 0.987D; n-butyraldehyde= 0.013D

 43

iso- butyraldehyde= 34.382 kmols/hr n-butyraldehyde= 0.453 kmols/hr

In Bottom Product (W)

n- butyraldehyde= 0.988D; iso- butyraldehyde= 0.012D

n- butyraldehyde= 141.304 kmols/hr iso- butyraldehyde= 1.71624 kmols/hr

4.1.4 Cracker

Top Product D goes into cracker. 34.835 kmols/hr of stream goes into cracker; only 34.382

kmols/hr of iso- butyraldehyde was cracked while 0.453kmols/hr of n-butyraldehyde has

been purged.

FC
CRACKER

80% PASS YIELD

R2

Fig 7: Cracker Unit

( FC  R2 ) * 0.2  R2

34.382  R  5 R2

R2  8.5955kmols / hr
 44

Total number of moles of iso- butyraldehyde that goes into cracker (with recycle)

= 34.382 +8.5955= 42.9775kmols/hr

(Rxn 3) H 3 C-C(CHO)-CH 3 metalcatal

  yst
 H 2 C  CH  CH 3  CO  H 2

From stoichiometry of cracking process (Rxn 3); 1 mole of iso- butyraldehyde cracks into

1mole propylene, 1 mole CO and 1mole H2

Hence, 42.9774kmols/hr of iso- butyraldehyde yields

42.9774kmols/hr propylene; 42.9774kmols/hr CO and 42.9774kmols/hr H2. All are recycled

back to OXO reactor.

4.1.5 Distillation column (DC) 1

n- Butyraldehyde IN = 0.752P = 141.684kmols/hr

$ Convert to kg by multiplying with Molecular mass of 72.11kg/kmols

= 141.684 * 72.11= 10216.83 kg

Iso- butyraldehyde IN = 0.192P = 36.175kmols/hr

$ Convert to kg by multiplying with Molecular mass of 72.11kg/kmols

= 36.175 * 72.11= 2608.58 kg

n- butanol IN = 0.06*0.8*P = 9.0437kmols/hr

 45

$ Convert to kg by multiplying with Molecular mass of 74.122kg/kmols

= 9.0437 * 74.122= 670.34 kg

iso- butanol IN = 0.04*0.2*P = 1.50728kmols/hr

$ Convert to kg by multiplying with Molecular mass of 74.122kg/kmols

= 1.50728 * 74.122= 111.723 kg

Heavy ends is 1% by weight of butyraldehydes/ butanol mixture

Adding up 10216.83 + 2608.58 + 670.34 + 111.723= 13607.473 kg

Heavy ends = 0.01 * 13607.473

= 136.075 kg

Total weight = 13607.473 + 136. 075

= 13743.53 kg

4.1.6 Oxo reactor

P= 188.41 kmoles/hr of butyraldehydes/butanols formed in OXO reactor

From stoichiometry; Propylene feed: butyraldehyde is 1:1. Hence, 188.41 kmoles/hr

Propylene is needed. Also 188.41 kmoles/hr of Synthesis gas.

 46

Assuming 98% conversion of propylene (2% yielded heavy ends) + 3% converted to

propane; actual amount of propylene fed into OXO reactor is

188.41
 198.326kmoles of propylene actually went into OXO reactor
0.95

198.326- 42.9775(cracker recycle)= 155.3545 (fresh feed + stripped propylene)

Synthesis gas IN = 2 * 155.3545

= 310.709 kmoles/hr

Unreacted Propylene(2%) = 0.02 * 198.326

= 3.967 kmoles/hr

Propane formed (from 3% propylene) = 0.03 * 198.326

= 5.95 kmoles/hr

Component Ratios on 310.709 kmoles/hr of Synthesis Gas

%H2= 48.6 = 0.486 * 310.709

= 151 kmoles/hr H2

%CO= 49.5 = 0.495 * 310.709

= 153.801 kmoles/hr CO

%CH4= 0.4 = 0.004 * 310.709

= 1.2428 kmoles/hr CH4

 47

%N2= 1.5 = 0.015 * 310.709

= 4.6606 kmoles/hr N2

Total CO in OXO reactor= 153.801 + 42.9775= 196.7785 kmoles/hr

Total H2 in OXO reactor= 151 + 42.9775 + 138. 494

= 332. 472

To determine exact amount of propane leaving the OXO reactor, it requires taking excess

(unreacted) propylene across the gas- liquid separators.

GLS 1: A certain amount of propylene dissolves in GLS 1 while the remaining is given off.

Solubility of propylene= 7.5 * 10-3 kg/kg liquid

Total weight of liquid leaving OXO reactor into GLS1= 13743.53 kg

Amount of propylene that dissolves = 0.0075*13743.5

= 103.08 kg

3.966 kmols/hr of propylene were fed into GLS 1, i.e., 3.966 * 42.08 = 166.89 kg

Hence, propylene given off= (166.89 – 103.08)= 63.81kg

This is equal to 1.516 kmols/hr of propylene given off.

GLS 2:

103.08
Amount of propylene into GLS 2= = 2.45 kmols/hr
42.08
 48

This amount of propylene is completely stripped by synthesis gas, and recycled back to

OXO reactor.

Propylene in Fresh Feed + Stripped Propylene= 155.3545 kmols/hr

Propylene in Fresh feed= 155.3545- 2.45= 152.9 kmols/hr

Propane is 7% of Fresh Propylene feed.

7
Propane in Fresh feed= *152.9  11.509kmols/ hr
93

Total Propane = 11.509 + 5.95

= 17.459 kmols/hr

Table 5 gives the material balance outlook on components involved in the oxo reactor.

Cobalt is 1% by weight of the inputs into hydroformylation reactor. However, unlike heavy

ends that is purged, Cobalt is constantly being recycled; hence, no need to include it in

material balance.

kg Cobalt=

1
((198.33 * 42.08)  (196.7785 * 28)  (332.472 * 2)  (11.509 * 44)  (4.6608 * 28)  (1.2428 * 16)
99

 146.59
 49

Table 5: Material Balance Data for Inputs and Outputs of OXO Reactor.

COMPONENT(kmols/hr) IN(kmols/hr) EXIT (kmols/hr)

Propylene 198.33 3.966

CO 196.7785 8.3658

H2 332.472 127.561

Propane 11.509 17.459

N2 4.6608 4.6608

CH4 1.2428 1.2428

Heavy Ends (kg) - 136.075

n- butyraldehyde - 141.684

isobutyraldehyde - 36.175

n- butanol - 9.0437

iso- butanol - 1.5073

 50

4.1.7 Gas- liquid separator (GLS) 1

Q, Steam

Oxo Exit
GLS 1

Off gases

Cobalt Catalyst Filter

Fig 8: Gas- Liquid Separator (GLS) 1

From solubility properties of the gases, we calculate the amount that dissolves in GLS 1.

Dissolved Propylene= 7.5*10-3* 13743.54= 103.08kg ≡ 2.45kmols/hr

Dissolved Propane= 7.5*10-3* 13743.54= 103.08kg≡ 2.343kmols/hr

Dissolved CO = 0.53*10-3* 13743.54= 7.28kg≡ 0.26 kmols/hr

Dissolved H2= 0.08*10-3* 13743.54= 1.10kg≡ 0.55 kmols/hr

Dissolved gases are sent into GLS- 2. Undissolved components of the gases above and

N2/CH4 inerts are discharged off.

Weight of Propylene IN= 3.966 * 42.08= 166.89kg

 51

166.89  103.08
Off gas propylene=  1.516kmols/ hr
42.08

Weight of CO IN= 8.3658* 28= 234.2424kg

234.2424  7.28
Off gas CO=  8.1058kmols / hr
28

Weight of H2 IN= 127.561* 2= 255.122kg

255.122  1.1
Off gas H2=  127.011kmols/ hr
2

Weight of Propane IN= 17.459* 44= 768.196kg

768.196  103..08
Off gas propane=  15.116kmols/ hr
44

These changes in some component products from OXO exit were effected, as shown in

Table 6. Table 6 gives the inlet- outlet data for GLS-1, where the outlet proceeds to GLS-2,

as well as off gases discharged from certain components.

 52

Table 6: Material Balance Data for Inlets, Outputs and Off- Gases for GLS 1

COMPONENT(kmols/hr) INLET 3(kmols/hr) EXIT (kmols/hr) Off

Gases(kmols/hr)

Propylene 3.966 2.450 1.516

CO 8.3658 0.26 8.1058

H2 127.561 0.55 127.011

(Recycled)

Propane 17.459 2.343 15.116

N2 4.6608 - 4.6608

CH4 1.2428 - 1.2428

Heavy Ends (kg) 136.075 136.075 -

n- butyraldehyde 141.684 141.684 -

isobutyraldehyde 36.175 36.175 -

n- butanol 9.0437 9.0437 -

iso- butanol 1.5073 1.5073 -

3
INLET represents the exit of oxo reactor
 53

4.1.8 Gas- liquid separator (GLS) 2

By the design statement, the GLS 2 achieves total stripping of propylene (for recycle back

to oxo reactor). Hence 2.45 kmols/hr stripped propylene is recycled.

Also remnants of propane, CO, H2 are discharged. Table 7 gives data values for resultant

process in GLS 2.

4.1.9 Material balance analysis

A complete overview table on the flowrates (in kmols/hr) of the various material

components in the major equipment is as given in the Table 8. A number of streams were

purged off in intermediate processes to avoid contamination of desired products. Careful

considerations were given to equipment with limited efficiencies, such as the Aldol reactor

and cracker, and proper recycle processes were devised to ensure optimization.

To produce 72000 tons/year of 2- Ethylhexanol, which is equivalent to 69.247 kmols/hr at

purity of 99 wt %, 198.33 kmols/hr of propylene will be required. This includes 152.9

kmols/hr of fresh feed, and others made up from recycled streams and cracked iso- butanal.

Also, 196.7785 kmols/hr of CO and 332.472 kmols/hr of Hydrogen (synthesis gas) will be

needed for the cobalt carbonyl- catalyzed hydroformylation reaction.

 54

Table 7: Material Balance Data for GLS- 2

COMPONENT(kmols/hr) INLET (kmols/hr) EXIT (kmols/hr)

Propylene 2.450 - 2.45 (Recycled)

CO 0.26 - 0.26

H2 0.55 - 0.55

Propane 2.343 - 2.343

Heavy Ends (kg) 136.075 136.075

n- butyraldehyde 141.684 141.684 -

isobutyraldehyde 36.175 36.175 -

n- butanol 9.0437 9.0437 -

iso- butanol 1.5073 1.5073 -

 55

Table 8: Overall Material Balance on Major Equipment (Dry Basis)

EQUIPMENT OXO REACTOR GLS 1 GLS 2 DC 1 DC 2 CRACKER ALDOL REACTOR HYDROGENATOR

COMPONENT INLET EXIT INLET EXIT INLET EXIT INLET EXIT INLET EXIT INLET EXIT INLET EXIT INLET EXIT
PROPYLENE 198.3300 3.9660 3.9660 2.4500 2.4500 - - - - - - 42.9775 - - - PROPYLENE
CO 196.7785 8.3658 8.3658 0.2600 0.2600 - - - - - - 42.9775 - - - - CO
H2 332.4720 127.5610 127.5610 0.5500 0.5500 - - - - - - 42.9775 - - 280.3522 138.494 H2
PROPANE 11.5090 17.4590 17.4590 2.3430 2.3430 - - - - - - - - - - - PROPANE
N2 4.6608 4.6608 4.6608 - - - - - - - - - - - - - N2
CH4 1.2428 1.2428 1.2428 - - - - - - - - - - - 3.3642 3.3642 CH4
HEAVY ENDS (kg) - 136.0750 136.0750 136.0750 136.0750 136.0750 136.0750 - - - - - - - - - HEAVY ENDS (kg)
N- BUTYRALDEHYDE - 141.6840 141.6840 141.6840 141.6840 141.6840 141.6840 141.6840 141.6840 141.6840 0.453 - 141.305 14.1305 - - N- BUTYRALDEHYDE
ISO- BUTYRALDEHYDE - 36.1750 36.1750 36.1750 36.1750 36.1750 36.1750 36.1750 36.1750 36.1750 42.9775 8.5955 1.7162 - - - ISO- BUTYRALDEHYDE
N- BUTANOL - 9.0437 9.0437 9.0437 9.0437 9.0437 9.0437 - - - - - - - - - N- BUTANOL
ISO- BUTANOL - 1.5073 1.5073 1.5073 1.5073 1.5073 1.5073 - - - - - - - - - ISO- BUTANOL
2- EthylHexenal - - - - - - - - - - - - - 69.946 69.946 0.699 2-ETHYLHEXENAL
2- EthylHexanol - - - - - - - - - - - - - - - 69.247 2- EthylHexanol
 56

4.2 Energy Balance

The energy balance for the Hydroformylation reactor and the Cracker unit was carried out

based on the following postulates;

 The reactants entering the reactor & cracker go from their entrance temperature to

the reference temperature, 298K or 25oC

 The products go from the reference temperature to their nominal exit temperature.

 The quantity of cooling water or steam needed is calculated as:

Overall enthalpy change = mass of water × specific heat capacity of water × Temperature

change

4.2.1 Hydroformylation reactor

H2 + CO + CH3CH=CH2 → CH3CH2CH2CHO (normal) + (CH3)2CHCHO

(Iso)

Reference temperature 25oC or 298K

Operating condition

T = 403.15k

P = 350 Bar
 57

Table 9: Enthalpy of Formation of the Feed Stream4

Component Hof (kJ/kmol) Molar flow (Table Heats of Reaction

(at 298K) 1) (kJ/hr)

(kmol/hr)

Propylene 19.71 198.330 3909.0843

CO -110.525 196.778 -21748.943

H2 0 332.472 0

Propane -104.68 11.509 -1204.76212

Methane -74.5 4.6608 -347.22960

Nitrogen 0 1242.8 0

4
Appendix C, Table C-4, Van Ness, Smith & Abbott, Introduction to CHE Thermodynamics, 6th Ed; p. 637
 58

Total Enthalpy of formation of the inlet components into the hydroformylation reactor =

3909084.3 + (-21748943.71) + 0 + -1204762.12 + -347229.60 + 0 = -193911.85113kJ/hr

Assuming there is no heat loss to the environment and the heat of mixing is negligible;

T
C p 
Thus, Q = (net) niH°f + ni  dT
T0
R

Where:

Q = Total Heat Balance on the Hydroformylation Reactor

ni = no of mole of each product in the reactor

H°R = Standard heat of reactor at reference temperature to

C p  = Standard heat capacity change

Total Enthalpy of Formation of Products= -19193.304-5118.763-586.032-106.536-

1827.608 + (3.966*19.71) + (-110.525*8.3658)+(0*127.561)+(-104.68*17.459)

+(0*4.6608) +(-74.5*1.2428)= -29598.9 kJ/hr

 59

Table 10: Heat of Formation of Product Stream in KJ/mol at 298K

Component Hof (kJ/mol) Molar flow (Table Heats of Reaction

(at 298K) 1) (kJ/hr)

(mol/hr)

n-Butyraldehyde -135.5 14.1648 -19193.304

Iso- Butyraldehyde -141.5 36.175 -5118.7625

n- Butanol -64.8 9.0437 -586.03176

Iso- Butanol -70.68 1.5073 -106.536

Propane (formed + -104.68 17.459 -1827.608

impurity)

Heavy End Unknown Unknown Unknown

 60

Energy Balance

Water

Heat of Reaction

Inlet stream

Enthalpy OXO Reactor

Exit stream Enthalpy

Cooling Water

Inlet stream + Dry saturated = Exit Stream + Heat of

Enthalpy stream enthalpy Enthalpy Reaction

+ Wet Saturated water enthalpy

Simply put, an energy balance for the OXO reactor is given by

 H in  H F  Qsup plied  H out

The Enthalpy in bringing the reactants from 403.15K to reference temperature (i.e  H in )

+ Enthalpy of Formation ( H F ) at 298K + Any heat supplied (or removed) by Dry Steam/

Cooling water streams) equals the Enthalpy in taking the products from reference

temperature back to from 403.15K (reactor temperature).

Table 4 shows the extracted Cp values from the literature. The relationship below was used

to estimate the enthalpy values for any stream:

 61

T
ni  C p dT where ni is the number of moles of a particular component,
T0

Cp = A + BT + CT2 + DT3

Table 11: Extracted Cp Data for Major Components (Coulson and Richardson, 2007)

From the table above; we compute values of  Hin

 H in = Propylene + CO + H2 + Propane + Methane + Nitrogen

n Hpropylene=

298 .15
2
198.330  3.71  0.235T  (1.16E  04)T  (2.20 E  08)T 3  1514225kJ / hr
403 .15

Similar values can be computed for other components. For certain components present in

both inlet and exit streams we simply take a net mole balance product on CP, since the

temperatures simply alternate.

 62

Hence; Hpropylene=

298 .15
2
(198.330 + 3.966)  3.71  0.235T  (1.16 E  04)T  (2.20 E  08)T 3 dT =
403 .15

-1544505.274kJ/hr

For CO= -699971.385 kJ/hr ; H2= -2396883.824 kJ/hr ; Propane =-257912.5186 kJ/hr

(N2 and CH4 is Zero).

Other Streams are the aldehydes and alcohols (exit only)

n- Butyraldehyde= +1778840.221 kJ/hr

iso- butyraldehyde= +471978.9746 kJ/hr

n- Butanol= +117898.32 kJ/hr

iso- butanol= +18259.60 kJ/hr

From the equation

 H in  H F  Qsup plied  H out ; make Qsupplied subject of formula

Qsup plied =  ( H in  H F )  H out

Evaluating= 1778840.221+471978.9746+117898.32+18259.60-(-257912.5186-

2396883.824-699971.385-1544505.274) -193911.85113 + 29598.9 kJ/hr

Qsup plied = + 7117937.166 kJ/hr

 63

Sensible Heat = Hv sat - HL sat

Where: Hv sat = Enthalpy of Dry saturated steam at 298 K

HLsat = Enthalpy of wet saturated water at 298 K

From Literature, Hvsat = 2557.3KJ/kg

HLsat = 104.8KJ/kg

Let M1 represent the mass flowrate to the Reactor.

Heat change = sat Hv - sat HL

7117937.166 kJ/hr = (2557.3 – 104.8) M1

7117937.166 kJ/hr = 2452.5 M1

M1 = 2902.32kg/hr

= 2.9 tonnes/hr of cooling water

 64

4.2.2 Cracker

Wet saturated liquid (water)

35 Bar

Iso-Butanal Cracker exit stream

CRACKER
Stream CO

i.e. 98.7% Iso-butanal H2

1.3% n-Butanal Propylene

Unreacted Iso-butanal

Dry saturated steam

35 Bar

Heat In + Heat Generated = Heat Out

Heat of formation + Sensible Heat + Dry steam enthalpy + Heat of reaction = (CO,

H2, propylene) Enthalpy + Enthalpy of wet saturated water

Enthalpy of formation of Cracker inlet stream components

Component Hof (KJ/mol) Molar Flow, ni niHof (KJ)

Iso-Butanal -215.87 34382 -7422.04

n-Butanal -205.15 0435 -89.24

∑ = -7511.280 KJ
 65

The operating temperature (435K) is out of range of T-max in which heat capacity values

of components given in literature can be valid, thus, we have to result to lee/Kesler

properties of components to evaluate Reduced Temperature (Tr) and reduced pressure (Pr)

needed for Lee/Kesler correlation.

Residual enthalpy correlation by Lee/Kesler is used to estimate one sensible heat because

the operating condition of cracker is out of range of T-max and P-max Values within which

specific enthalpy (Cp) values in the literature are valid.

QS = Hof + HR = ∑niHofi + ∑ni HRi

Calculation of sensible heat for raising temperature of inlet stream from 250C to 2750C

Component Tc Pc Tr Pr ω

Iso- Butanal 513 41.5 1.068 0.0241 0.34499

n- Butanal 524 40.5 1.046 0.0247 0.3519

The following values below were extenuated from the general Lee/Kesler Residual

enthalpy data by double interpolation for Tr and Pr.

Component HR o (HR)1 ω ω (HR)1 HR

RTc RTc RTc

Iso- Butanal -0.0213 -0.0165 0.3499 -0.00577 -0.0271

n- Butanal -0.0228 -0.0184 0.3519 -0.00647 -.0293

 66

Where; HR = (HR)0 + W(HR)1

RTc RTc RTc

Residual Enthalpy Calculation

Component HR Tc R HR Molar flow HR(kJ)

RTc (kJ/kmol) (kJ/kmol) rate (mol/hr)

Iso- Butanal -0.0271 513 8.314 -115.58 34382 -3973.872

n- Butanal -0.0293 524 8.314 -127.64 435 -55.523

∑niHR -4029.202 kJ

Sensible Heat H = ∑niHof + ∑niHiR

= -7511.280 - 4029.202

= -11540.482 kJ

H = -11540.482 kJ

Heat of Reaction of Iso-Butanal stream into Cracked gases

From Reaction Data,

(CH3)2CHCHO CH3-CH = CH2+ H2+CO ΔH0R =129.5KJ/mol

Note: Negative sign of ΔHoR in Reaction Data given is reversed since the reaction is

reversed.
 67

Component ΔHoR (KJ/Mol) Molar Flow, ni ΔHoR ni (kJ)

Iso-Butanal 129.5 34382 4452.469

n-Butanal 64.8 435 28.188

∑ ΔHoR ni 4480.657 kJ

Energy Balance

Sat.d Water

Heat of Inlet stream Heat of Exit stream

Heat of Reaction Sat Steam

35Bar

Heat of Exit Stream = Heat of Inlet stream + Heat of Reactor

= Heat of formation + Sensible + Heat of Reaction

of Reactants Heat

= -7511.280 + -11540.482 kJ + 4480.657 kJ

= -14571.105kJ

Amount of steam used for the reaction.

 68

Hv sat - HL sat = Sensible Heat

Hv sat of steam at 35 Bar = 2631.15KJ/Kg

Hvsat of water at 35 Bar = 303.476KJ/kg

Let M2 = mass flowrate of the steam used.

Thus: (2631.15– 303.476)M2 = 14571.105 KJ

2327.674M2 = 14571.105 KJ

M2 = 6.26 tons/hr of steam

4.2.3 Energy balance analysis

In computing the energy balances for the two reactors, a number of minimal assumptions

were optioned. For the oxo reactor operating at 350 bar and 403.5 K, the total enthalpy of

entry reactants is -193911.85113kJ/hr, while the enthalpy of formation of products (at 298

K basis) was -29598.9 kJ/hr The heat supplied from the utility stream (in this case cooling

water at 298 K) was obtained from heat balance as + 7117937.166 kJ/hr, and the

corresponding mass flow rate was 2.9 tons/ hr of cooling water.

For the cracker unit, Dry saturated steam was supplied at 35 bar as utility at a mass flow

rate of 6.26 tons/ hr.

 69

CHAPTER FIVE

EQUIPMENT SCHEDULE AND P&ID

5.1 Design Conditions and Physical Properties of Oxo Reactor

To determine the feed stream volumetric flowrate, we sum up the IN column in Table 5:

198.33 + 196.7785 + 332.472 + 11.509 + 4.6608 + 1.2428= 744.9931 kmols/hr

Assuming a Feed molar volume of 0.10m3/kmol, the Feed stream volumetric flowrate =

(0.1 × 744.9931) m3/hr

= 74.50m3/hr

Assuming a 98% conversion in the reactor, the residence time can be interpolated from

experimental data given below (Levenspiel, 1999)

Conversion(%) Time(min)

96.489 90
98 Tr
99.5 105.432

For 98% conversion, residence time (Tr) can be calculated as thus

. . .
= .

Tr = 99.250mins
 70

Total volume of reactant in the reactor

Total volume of reactant = Volumetric flowrate × residence time

99.25
= 74.50 m3/hr  60 hr

= 123.24 m3

By design heuristics, design temperature and pressure of a reactor should be 10 % excess of

the operating temperature and pressure. Since the operating condition of the reactor is

130oC and 350bar, then,

Design temperature = 1.1 * 130oC = 143oC

Design pressure = 1.1* 350 Bar = 385 Bar

Dimension of Oxo-Reactor: Heuristics have it that the reactor is generally 90% full and

the height is thrice the diameter (Bassel, 1974). Therefore,

123.24
Volume of the reactor = = 136.93 m3
0.9

Assuming that the reactor is Cylindrical Shaped with hemispherical ends

2 * r 3  * D 2 L
Total Volume of the reactor tank = 2  
3 4

Where r = radius of cylinder and hemisphere

L = length of the cylindrical part of the reactor

H = height of the reactor

Then height of reactor, H = L + 2r = L + D

Then, L = H – D, hence
 71

4  * r 3  * D 2 ( H  D)
Volume of the reactor, V = 
3 4

Substituting r = into the equation above, we have

 * D 3  * D 2 ( H  D)
V= 
6 4

(By Heuristics Height of tank = 3 × Diameter)

 * D 3  * D 2 (2D)
V= 
6 4

2 * D 3
V=
3

2 * D 3
Then, Volume of reactor = = 136.93m3
3

Diameter, D = 3.519m,

Then Height, H = 3D = 3 × 3.519m = 10.558m

Length of cylinder = H - D

= (10.558 – 3.477)m

= 7.038m

5.2 Design Conditions and Physical Properties of Cracking Unit

From Table 8, the total feed input into the cracker = 0.453 +42.9775 = 43.4305 kmols/hr.

Also the molar flowrate of i-butyraldehyde feed into the cracking unit is 42.9775 kmol/hr

and that of n-butyraldehyde is 0.453 kmol/hr. Residence time still remains 99.25 mins

Molar mass of butyraldehyde = 72.12 kg/kmol

Mass flow rate of i-butyraldehydes = 72.12 kg/kmol × 42.9775 kmol/hr = 3099.5373 kg/hr
 72

.
Mass = 3099.5373 kg/hr × hr = 5127.15 kg

Density of i- Butyraldehyde = 802 kg/m3, hence,

.
Volume = = = 6.393 m3

Mass flow rate of n-butyraldehydes = 72.12 kg/kmol × 0.453 kmol/hr = 32.671 kg/hr
.
Mass = 32.671 kg/hr × hr = 54.042 kg

Density of n- Butyraldehyde = 794 kg/m3, hence,

.
Volume = = = 0.068 m3

Total volume = (6.393 + 0.068) m3 = 6.461 m3

Heuristics have it that it is safe to have a storage tank filled up to 90% of its capacity

(Bassel, 1974) to avoid explosion, hence

.
Actual Volume = .
= 7.178m3

Assuming that the cracking unit have the same shape as the Oxo-reactor, then

2 * D 3
V= = 7.178 m3
3

Diameter D = 1.508 m

Height, H = 3 × D = 3 × 1.508m = 4.523m

Length, L = H – D = 4.523 m – 1.508 m

= 3.015 m

Design temperature = 1.1 × 275oC = 302.5oC

Design pressure = 1.1 ∗ 1 Bar = 1.1 Bar

 73

5.3 Design Conditions and Physical Properties of Aldol Condenser

From Table 8, the total feed input into the Aldol Condenser is 141.305 + 1.7162= 143.0212

kmols/hr

From material balance, it has been calculated that the molar flowrate of n-butyraldehyde

feed into the Aldol condenser is 141.305 kmol/hr and that of i-butyraldehyde is 1.7162

kmol/hr. Residence time still remains 99.25 mins

Molar mass of butyraldehyde = 72.12 kg/kmol

Mass flow rate of n-butyraldehyde = 72.12 kg/kmol ×141.305 kmol/hr = 10190.92 kg/hr
.
Mass = 10190.92 kg/hr × hr = 16857.474 kg

Density of n- Butyraldehyde = 794 kg/m3, hence,

.
Volume = = = 21.23 m3

Mass flow rate of i-butyraldehydes = 72.12 kg/kmol × 1.7162 kmol/hr = 123.772 kg/hr
.
Mass = 123.772 kg/hr × hr = 204.74 kg

Density of i- Butyraldehyde = 802 kg/m3, hence,

.
Volume = = = 0.255 m3

Total volume = (21.23 + 0.255) m3 = 21.485 m3

Heuristics have it that it is safe to have a storage tank filled up to 90% of its capacity

(Bassel, 1974) to avoid explosion, hence

.
Actual Volume = = 23.873 m3
.

Assuming that the Aldol condenser unit have the same shape as the Oxo-reactor, then
 74

2 * D 3
V= = 23.873 m3
3

Diameter D = 2.251 m

Height, H = 3 × D = 3 × 2.251 m = 6.752 m

Length, L = H – D = 6.752 – 2.251 m = 4.50 m

Since the operating condition of the reactor is 115oC and 3bar, then, by heuristics

Design temperature = 1.1 × 115oC = 126.5oC

Design pressure = 1.1 × 3 Bar = 3.3 Bar

5.4 Design Conditions and Physical Properties of Hydrogenation Reactor

From Table 8, total feed input into the hydrogenation reactor = 280.3522 + 3.3642 +

69.946 = 353.6624 kmols/ hr

From material balance, it has been calculated that the molar flowrate of hydrogen feed into

the reactor is 280.3522 kmol/hr.

Volume occupied at STP & having 99.25mins as the residence time

.
Volume = 280.3522 kmol/hr × hr × 22.4m3/kmol = 10387.984 m3

Assuming that the hydrogenation reactor have the same shape as the Oxo-reactor, then

2 * D 3
V= = 10387.984 m3
3

Diameter D = 17.054 m

Height, H = 3 × D = 3 × 17.054 m = 51.162 m

Length, L = H – D = 51.162 – 17.054 = 34.108 m

 75

Heuristics have it that it is safe to have a storage tank filled up to 90% of its capacity

(Bassel, 1974) to avoid explosion, hence

.
Actual Volume of Hydrogenation reactor = .
= 11452.204 m3

Since the operating condition of the reactor is 150oC and 50bar, then, by heuristics

Design temperature = 1.1 × 150oC = 165oC

Design pressure = 1.1 × 50 Bar = 55 Bar

Table 12 gives the design parameters of these major plant items as calculated above.

5.5 Capacity of Storage Tanks

5.5.1 Propylene feed storage tank

From material balance, it was calculated that the fresh propylene feed from the propylene

tank is 152.9 kmol/hr. Having calculated the residence time which can be said to be

equivalent to the retention time of propylene in the propylene tank, at STP condition
.
Volume of Propylene = (152.9 kmol/hr × ) × 22.4 m3/kmol = 5665.45 m3

Heuristics have it that it is safe to have a storage tank filled up to 90% of its capacity

(Bassel, 1974) to avoid explosion, hence

.
Volume of propylene storage tank = .
= 6294.95 m3

Taking the shape of the storage tanks as cylindrical forms, then,

V= , where H = 3D

V=3 = 6294.95m3

D = 8.741 m; H = 3 × 8.741 m = 26.224m

 76

Table 12: Design Parameters of Some Major Plant Items

Vessel/ Oxo Reactor Cracker Aldol Hydrogenation

Parameter Condenser Reactor

Volume (m3) 136.93 6.461 23.873 11452.204

Diameter (m) 3.519 1.508 2.252 17.054

Height (m) 10.558 4.523 6.752 51.162

Length (m) 7.038 3.015 4.500 34.108

Pressure (bar) 385 1.1 3.3 5.5

Temperature(°C) 143 302.5 126.5 165

 77

5.5.2 Synthesis gas storage tank

From material balance, it was calculated that the fresh synthesis gas from the storage tank

is 310.709 kmol/hr. Having calculated the residence time which can be said to be

equivalent to the retention time of Synthesis gas in the storage tank, at STP condition
.
Volume of Synthesis gas = 310.709 kmol/hr × × 22.4 m3/kmol = 11512.804

m3

Heuristics have it that it is safe to have a storage tank filled up to 90% of its capacity

(Bassel, 1974) to avoid explosion, hence

.
Volume of Synthesis gas storage tank =
.
= 12792 m3

Taking the shape of the storage tanks as cylindrical forms, then,

V= , where H = 3D

V=3 = 12792 m3

D = 11.072 m

H = 3 × 11.072 m = 33.216 m

5.5.3 Hydrogen gas storage tank

From material balance, it was calculated that the fresh hydrogen gas from the storage tank

is 280.352 kmol/hr (with methane impurity). Having calculated the residence time which

can be said to be equivalent to the retention time of hydrogen gas in the storage tank, at

STP condition

Volume occupied at STP & having 99.25mins as the residence time

.
Volume = 280.3522 kmol/hr × hr × 22.4 m3/kmol = 10387.984 m3
 78

Heuristics have it that it is safe to have a storage tank filled up to 90% of its capacity

(Bassel, 1974) to avoid explosion, hence

.
Volume of Hydrogen gas storage tank = .
= 11542.20 m3

Taking the shape of the storage tanks as cylindrical forms, then,

V= , where H = 3D

V=3 = 11542.20 m3

D = 10.70 m

H = 3 × 10.70 m = 32.1 m

5.5.4 2-Ethyl hexanol product storage tank

From material balance, it was calculated that the 2-Ethyl hexanol produced was 69.247

kmol/hr. Having calculated the residence time which can be said to be equivalent to the

retention time of 2-Ethyl hexanol in the storage tank and density of 2-Ethyl hexanol is

833.00 kg/m3

Molar mass of 2-Ethyl hexanol = 130.23 kg/kmol

.
Mass flow rate 2-Ethyl hexanol = 69.247 kmol/hr × hr × 130.23 kg/kmol =

14917.336kg
.
Volume = = 17.908 m3
.

Heuristics have it that it is safe to have a storage tank filled up to 90% of its capacity

(Bassel, 1974) to avoid explosion, hence

.
Actual Volume of 2-Ethyl hexanol storage tank = = 19.898 m3
.

Taking the shape of the storage tanks as cylindrical forms, then,

 79

V= , where H = 3D

V=3 = 19.898m3

D = 1.283 m

H = 3 × 1.283 m = 3.850 m

5.6 Materials of Construction

The standard material of construction is carbon steel. It is usually the cheapest metal that

can be used in fabricating equipment. However, it generally is not used below -45.6oC

because of a loss of ductility and impact strength, nor is it generally used above 510 oC,

because of excessive scaling rates. It is not good for mildly acidic conditions, because

under these circumstances corrosion is greatly accelerated. Carbon steel cannot be used in

the production of most polymers because even trace amounts of iron discolor the product.

In polymer manufacturing, usually glass-lined or stainless steel equipment must be used.

Glass-lined or stainless steel equipment is required for any product that may be ingested by

man. This includes all foods, pharmaceuticals, and food additives.

The temperatures and pressures in the processing equipment are a function of the

processing conditions and the properties of the substances used. For instance, the highest

temperature in a distillation column can be estimated by knowing the boiling points of all

the key components at the operating pressure. The highest boiling point will be close to the

highest temperature that will occur within the column.

The temperatures and pressures in the storage system depend on the physical properties of

what is being stored and the weather conditions.

 80

Table 13: Physical Parameters of Storage Tanks

Tank/ PropyleneFeed Synthesis Gas Hydrogen 2- EH

Parameter

Volume (m3) 6294.950 12792 11542.20 19.898

Diameter (m) 8.741 11.072 10.70 1.283

Height (m) 26.224 33.216 32.10 3.850

 81

Table 14: Material of Construction and the Operating Temperatures and Pressure of the Major Items of Equipment
Equipment Physical Function Size (m3) Operating Material of Preferable Steam Cooling Water
Description Temperature Construction Characteristics
and Pressure
Hydroformylati Cylindrical For the 136.93 130 oC, 350 Austenitic Better corrosion - 2.9 tonnes/hr
on Reactor with a dome- reaction bar Stainless steel resistance and
shaped end between 304 (with few improved resistance to
Synthesis gas % molybdenum pitting.
and Propylene
gas
Gas-Liquid Cylindrical, Separation of 152.750 160 oC, 30 bar Low-Carbon Readily available, low 13.896ton/hr -
Separator 1 but with its the catalyst Steel (Type cost, excellent
lengthy side from the 304L and ductility and easily
place product 306L) welded
vertically
Gas-Liquid Cylindrical Separation of 147.328 55oC, 1 bar Low-Carbon Readily available, low 4.328 tons/hr -
Separator 2 with a dome- the gaseous Steel (Type cost, excellent
shaped end product from 304L and ductility and easily
the liquid 306L) welded
product
Distillation Oblong Separation of 157.928 72.55oC, 1 Ferritic Corrosion resistance 24.851ton/hr 16.746ton/hr
Column 1 Cylindrical butyraldehydes bar Stainless Steel and very resistant to
with a dome- from alcohols (Type 430) scaling and high-
shaped end temperature


Design Temperature & Pressure heuristically 1.1 times Operating Conditions
 82

Distillation Oblong Separation of 179.50 65.02oC, 1 Ferritic Corrosion resistance 18.728ton/hr 16.746ton/hr
Column 2 Cylindrical n- and i- bar Stainless Steel and very resistant to
with a dome- butyraldehydes (Type 430) scaling and high-
shaped end temperature
-
o
Cracking unit Cylindrical Thermal 6.461 275 C, 1 bar Low Alloy Better corrosion 6.26tons/hr
with a dome- cracking of i- steel, austenitic resistance and
shaped end butyraldehyde type 20% Cr; improved resistance to
29% Ni; 2.5% pitting
Mo; 3.5% Cu
o
Aldol Cylindrical Aldol 23.873 115 C, 3 bar Austenitic Better corrosion - 16.540 ton/hr
Condensation with a dome- Condensation Stainless steel resistance and
Reactor shaped end of n- 316 (with few improved resistance to
Butyraldehyde % pitting
molybdenum)
Hydrogenation Cylindrical Hydrogenation 11452.204 150 oC, 50 bar Austenitic Better corrosion 14.325ton/hr -
reactor with a dome- of 2-Ethyl Carbon steel resistance and
shaped end Hexenal to 2- (with few % improved resistance to
Ethyl Hexanol molybdenum pitting.
e.g. Stainless
steel type 316)
 Hydrogenator Oxo Reactor

K- 100: GLS 1; K- 101: GLS 2

K- 102: Regenerator

C3 + SYN GAS

Co Catalyst Filter

Cooling Water

n- Butanal

NaOH

OGUNGBENRO ADETOLA ELIJAH

CHE/2007/083
Piping and Instrumentation Diagram
2 - EH
P& ID

72 000 Tons/Year 2- Ethyl Hexanol Plant

V- 340
Hydrogenator Aldol Condenser 2- EH Plant 2012/11/15
 84

CHAPTER SIX

CHEMICAL ENGINEERING DESIGN

Fig 9: Distillation Column (DC) 2

Feed F is saturated liquid at boiling point.

M = 72.11 kg/kmol
 85

Composition of DC 2

Inlet Exit

n-butyraldehyde 141.68kmol/hr 0.453 kmol/hr (Top)

141.304 kmol/hr(Bottom)

i-butyraldehyde 36.175kmol/hr 35.704 kmol/hr (Top)

0.4341 kmol/hr (Bottom)

From equipment schedule completed, feed into Distillation Column 2 (DC2) is 177.86

kmols/hr. This contains 0.797 mole fraction n- butyraldehyde and 0.203 mole fraction iso-

butyraldehyde.

Hence, n- butyraldehyde= 0.797*177.86= 141.68 kmols/hr

Iso- butyraldehyde= 0.203*177.86= 36.175 kmols/hr

Feed enters DC 2 at 65°C

From VLE Date provided for iso- butyraldehyde (2.6.4)

At x= 0.2, T= 72.69°C; at x= 0.3, T= 71.40°C

Interpolating to obtain value at x= 0.2034 gives

0.2034  0.2 T  72.69

 I
0.3  0.2 71.40  72.69
 86

TI= 72.65°C

Thermal Properties of Butyraldehydes

Specific Heat Latent Heat

J/mol°C (J/mol)

Iso- butyraldehyde 160.9 29950

n- butyraldehyde 151 31490

Latent heat of feed = 31490*0.7966 + 29950 * 0.2034 J/mol

= 31176.764 J/mol

Mean Specific Heat = 151*0.7966 + 160.9*0.2034 J/mol°C

= 153.01366 J/mol°C

Heat required to = (mean specific heat * temperature gradient) + latent heat

vaporize 1 mol of feed

= (72.65- 65) * 153.01366 + 31176.764

= 32347.3185J

32347.3185
q =  1.0375
31176.764
 87

1.0375
Slope of q line =  27.634
1.0375  1

Fig 10 shows the x-y plot with the XB (iso-butyraldehyde concentration in bottoms), XD

(iso- butyraldehyde concentration in distillate) and Xf (iso- butyraldehyde concentration in

feed) marked. The q-line is drawn from the point of intersection of XF and the 45 degree

line with a slope of 27.634 using the line equation: y-y1 = M(x-x1). M is the slope, x1:y1 are

the coordinates of intersection of XF and the 45° line. Thus, we substitute a value for x to

get the corresponding y.

 88

Fig 10:x-y plot of Iso- butyraldehyde VLE Data

 89

The XD operating line is drawn through the point of intersection of the x-y plot and the line

to intersect the y axis at point 0.0925 (Fig 10). This corresponds to XD/ (Rm + 1), where Rm

is the minimum reflux ratio. Since XD = 0.987, we calculate Rm to be 9.6703. The optimum

reflux ratio R is obtained by using typical values suggested in the literature, and usually

ranges between 1.1 and 1.5. Thus we use

R = 1.5*Rm = 14.5054.

A new point XD/(R+1) is located on the y axis and the operating line of XD is drawn to pass

through this point. The operating line of XB is drawn to pass through the intersection of the

q-line and the new XD operating line and the steps are drawn as shown in Fig 11 to obtain

the number of trays required.

The number of trays obtained from the McCabe Thiele- Plot is 46 trays.
 90

46

Fig 11: McCabe- Thiele Plot for Distillation Column (DC) 2 (No of trays =46)
 91

FLOWRATES

L = R*D = 14.5054 (34.835) = 505.30.98 kmols/hr

G = L+ D = 505.30+34.835 = 540.131 kmols/hr

q=1 (Feed is saturated liquid)

L = L + q*F = 505.30+ 1(177.86) = 683.16 kmols/hr

G = G + (q –1) * F = 540.131 + 0 = 540.131 kmols/hr

6.1 Plate Hydraulics

6.1.1 Enriching section

Tray spacing (ts) = 18” = 457.2 mm

Hole diameter (dh) = 5 mm

Pitch (lp) = 3* dh = 3x 5 = 15 mm (For triangular pitch; lp= 3dh)

Tray thickness (tT ) = 0.6* dh = 3 mm

Area of hole Ah
 0.10
Area of Pitch Ap
 92

Table 15: Flow Properties of Distillation Column (DC) 2

Enriching Section Stripping Section

Top Bottom Top Bottom

Liquid (kmols/hr) 505.30 505.30 683.16 683.16

Liquid (kg/hr) 36437.183 36437.183 49262.67 49262.67

Vapour (kmols/hr) 540.131 540.131 540.131 540.131

Vapour (kg/hr) 38948.85 38948.85 38948.85 38948.85

x 0.987 0.203 0.203 0.012

y 0.987 0.268 0.268 0.012

Tliq (oC) 64.07 72.55 72.55 75.19

Tvap (oC) 64.300 73.00 73.00 75.30

ρliq(kg/m3) 739.58 744.930 744.930 745.60

ρvap(kg/m3) 2.584 2.539 2.539 2.730

(L/G)(ρg/ρL)0.5 0.0554 0.0546 0.0738 0.0765

σliq(dyn/cm) 16.100 17.800 17.800 18.000

µvap 8.39 x10-3 8.04 x10-3 8.04 x10-3 8.01 x10-3

µliq 0.349 0.298 0.298 0.290

Dvap(m2/s) 0.142 0.148 0.148 0.149

Dliq(m2/s) 4.92 x10-9 4.60 x10-9 4.60 x10-9 4.93 x10-9

 93

Plate Diameter (DC)

0.5 0.5
 L   g 
  505.30   g 

     0.0554 (maximum at top);
 G   L   540.131   L 

∴ Flooding check at top

Csb, flood = 0.28 ft/s

Csb, flood = Capacity parameter (ft/s)

Unf = Gas velocity through net area at flood (ft/s or m/s)

0.2 0.5
 20   g 
Csb, flood = Unf    
    
 L g 

= liquid surface tension= 16.1 N/m

Make Unf subject of formula

0.2 0.5
 16.1   739.58  2.584 
Unf = 0.28    
 20   2.584 

= 4.528 ft/s = 1.38 m/s

Consider 80% Flooding; Gas velocity, Un= 0.8*Unf = 1.104 m/s

G 38948.55(kg / hr )
Volumetric Flow rate of Vapor= 
3600 *  g 3600( s / hr ) * 2.584(kg / m 3

= 4.187 m3/s

Volumetric flow rate of vapor 4.187

Net Area (An) =   3.7925m 2
Un 1.104

Lw
Let  0.70 ; Lw= weir length, DC= Column Diameter
DC

2 2
Area of Column (AC) = 0.25 *  * DC  0.785 DC
 94

   L / 2 
sin  C    w   0.7
 2   DC / 2 
 C  88.85

 2 C Lw DC C 
Area of downcomer (AD) =  4 * DC 360  2 2 cos 2 
 

2
DC
= 0.775  0.5  0.0688DC 2
4

An= AC - AD

0.785DC2 - 0.0688DC2 = 3.7925

DC= 2.301m; DC ≈2.3m

Lw = 0.7*2.301= 1.611m

Lw ≈ 1.6m

AD = 0.0688*(2.301)2

= 0.3643 m2

AC = 0.25 *  * 2.3012  4.1584m 2

An = AC-AD = 4.1584- 0.3643 = 3.7941m2

Active Area (Aa) = AC - 2AD

= 4.1584- 2*(0.3643)

= 3.4298m2

Lw 1.6
  0.696;
DC 2.3
L 
 C  2 arcsin  w 
 DC 
 88.16
ACZ= 2(60mm) * Lw= 0.192m2
 95

A CZ 0.192
  0.0462
AC 4.1584

A CZ  4.6%A C

      180  88.16
 91.84
Waste Zone Area is AWZ

  2     
   DC  0.06 *
2
Waste zone area, Awz = 2 *  * DC 
 4 360   4 360 

= 2 * 1.06085  1.0062

= 0.1092m 2

A WZ 0.1092
  0.0262
AC 4.1584

Hence, Awz = 2.6% Ac

Area of perforation, Ap = Ac – 2Ad – Acz – Awz

= (3.4298 – 0.192 – 0.1092) m2

= 3.731 m2

Area of holes, Ah = 0.1 Ap

= 0.1 * 3.731

= 0.3731 m2

4 Ah 4 * 0.3731
Number of holes, nh = 
d h
2
 * (5 *10 3 ) 2

= 19002 Holes

Weir height, hw = 44mm

 96

Weeping Check for the Sieve Tray

pg 2
hd = K1 + K 2 ( )U h (Hobson et al., 1994) where
L

K1 = 0 (for sieve tray); Uh = Linear gas velocity through holes

hd = Pressure drop across dry hole (mm liquid)

50.8
K2  2
; where CV = Discharge coefficient
CV

Area of hole, Ah 0.3731

For   0.109 ; and
Active Area, Aa 3.4298

Tray Thickness, t T 3
  0.6 ; we have that
Hole Diameter, d h 5

CV = 0.74 (Hobson et al., 1994), then

50.8
K2 =  92.77
0.74 2

Uh =
× ×

38948.55
(Uh)top = = 11.222 m/s (minimum)
2.584 * 3600 * 0.3731

38948.5
(Uh)bottom = = 11.421 m/s (maximum)
2.539 * 3600 * 0.3731

pg 2 2.584
(hd)top = K2( )U htop = 92.77* ( ) *11.2222
L 739.58

= 40.818 mm of clear liquid

2.539
(hd)bottom = 92.77* ( ) *11.4212 = 41.244 mm of clear liquid
744.93
 97

  
hσ = 409   (Hobson et al. 1994)
 Ldh 

hσ= head loss due to the bubble formation

 16.1 
hσ= 409*   =1.78 mm of clear liquid
 739.58 * 5 

2
 q 3
Height of crest over weir, hOW = FW * 664 *   where
 LW 

FW = weir constriction correction factor

q = Liquid flow per serration (m3/s)

36437.183
q= =  13.69 *103 m 3 / s
× 739.58 * 3600

FW = 1.02 (Hobson et al., 1994)

2
 13.69 * 10 3  3
hOW = 1.02*664*    28 mm of clear liquid
 1.6 

Head loss due to bubble formation, hσ + Pressure drop across dry hole, hd =

= (1.78 + 40.818) mm = 42.598mm

Height of crest over weir, how + Weir height, hw = 44 + 28 = 72 mm

= 0.109; hw + how = 72 mm and hd + hσ = 15mm

Since 15mm < 42.598mm, then there is no weeping.

 98

Flooding Check.

Since the maximum flow rate occurs at the bottom, flooding will be checked at the bottom.

Height of clear liquid over the dispersal, hds = hW + hOW + hhg*0.5 (For sieve trays);

where hhg is the liquid gradient across plate (mm liquid)

(hOW)bottom = 27.9 mm

hds = 44 + 27.9 + 0 = 71.9 mm

Linear vapor velocity through active area,Ua= × ×

38948.55
Ua =  1.360m / s  4.46 ft / s
3600 * 2.539 * 3.4298

ρg = 2.539kg/m3 = 2.539 × 0.0625lb/ft3 = 0.1587 lb/ft3

Fga = Ua (ρg)0.5 (Hobson et al., 1994)

Fga = 4.46 × (0.1587)0.5 = 1.78

Aeration factor, β = 0.61; Relative frost density, Φt = 0.22

Pressure drop through aerated material, hl1 = β × hds = 0.61 × 71.9 = 43.859 mm

h1 ' 43.859
Actual height of froth, hf =   199.36mm
t 0.22

2
q 
Head loss under the down-comer, hda = 165.2  b  where
 Ada 

Ada = minimum area of flow under the down-comer apron

qb = volumetric flow rate of liquid at the bottom of the stripping section

hap = hds – c = 71.9 – 25 = 46.9 mm

Ada = LW × hap = 1.6 × 46.9 × 10-3 = 0.07504 m2

 99

Lb 36437.183
qb =
×
=   13.59 *10 3 m 3 / s
 L 3600.744.93

2
13.598 * 10  3 
hda = 165.2 ×    5.42mm
 0.07504 

Total head loss across the plate, ht = hd + hl' = 41.244 + 43.859 mm = 85.104mm

Total head loss across the rectifying section, hdc = ht + hw + how + hhg + had

= 85.104 + 44 + 27.9 + 0 + 5.42 = 162.424 mm

Taking relative froth density, Φdc average = 0.50;

162.424
Actual back-up, hdc =  324.848mm < 457.2mm
0.5

Since Actual back-up < Tray spacing, i.e. 324.848 mm < 457.2 mm, then it can be said that

flood checking is satisfied, i.e. there is no flooding

Column Efficiency (Average conditions)

0.5
0.776  0.00457h w – 0.238 U a  g  105 w
Gas phase transfer unit, Ng = (Hobson
(N sc, g ) 0.5

et al., 1994)

 g , ave 8.22 *10 3 * 10 3

Nsc,g = Gas phase Schmidt number = 
 g * Dg 2.562 * 0.142 *10  4

= 0.226

38948.55
Ua =  1.231m / s
3600 * 2.562 * 3.4298

LW  DC 1.6  2.3
Width of flow path on plate, Df =   1.95m
2 2
 100

q
Liquid flow rate, w = ;
Df

36.437.183
q= =  0.01369m 3 / s
× 739.58 * 3600

w= 7.018 *103 m 3 / m  s

(0.776  0.00457* 44) – 0.238 (1.231) (2.562) 0.5  (105 * 7.018 *10 -3
Ng =
(0.226)0.5

Ng = 2.619

Liquid phase transfer unit, NL = KLa × θL, where

KLa = Liquid phase transfer coefficient

θL = Residence time of liquid in froth or spray zone

(DL),average = 4.760 × 10-9

KLa = (DL,avg)0.5(0.40 * Ua * ρvap0.5 + 0.17) (Hobson et al., 1994)

KLa = (3.875 × 108 × 4.760 × 10-9)0.5(0.40 × 1.231 × 2.5620.5 + 0.17)

KLa = 1.300 m/s

hL Aa
θL = , where hL = Liquid hold-up on plate
1000qb

40.81* 3.4298
L   10.30 sec onds
1000 *13.59 *103

NL = 1.3 × 10.30 = 13.39

mtop =0.49; mbottom=1.15

G   Gm  38948.85
Stripping factor at top, λt = 0.49*  m  ;     1.069
 Lm   Lm  36437. 183

λt= 0.49*1.069 = 0.524

 101

Stripping factor at bottom, λb = 1.15 × (1.069) = 1.229

Average stripping factor, λ = 0.5 * (λt +λb)

λ= 0.877

1
N og 
1 

N g N liq

1
= = 2.24
1 0.877

2.619 13.39

EOG = 1 – e –Nog = 1 – e –(2.24) = 0.8935

Murphee Plate Efficiency, Emv

Since Residence time, θl = 10.30s which is quite large, then

Emv ≈ EOG = 0.8935

Overall Column Efficiency, Eoc

{ ( )}
Eoc = , where Ea = Murphee vapor efficiency
( )

= , where = fractional entrainment

0.5 0.5
L  g  36437.183  2.562 
For G     * 
38948.85  739.58  = 0.0551
 L 

For 80% flooding, using the referenced text, ψ = 0.06

1
Ea = 0.8935× ( ) = 0.8453
0.06
1  0.8935 *
1  0.06

log(1  0.8453* (0.877  1)

Eoc = = 0.8365
log(0.877)
 102

Number of theoretical traysN t 24

Number of actual trays, Na =   28.69  29 trays
EOC 0.8365

Height of rectifying section = Number of trays × tray spacing = 29 × 0.4572 = 13.26m

6.1.2 Stripping section

Tray spacing (ts) = 18” = 457.2mm

Hole diameter (dh) = 5mm

Pitch (lp) = 3* dh = 3x 5 = 15mm (For triangular pitch; lp= 3dh)

Tray thickness (tT ) = 0.6* dh = 3mm

Area of hole Ah
 0.10
Area of Pitch Ap

Plate Diameter (DC)

0.5 0.5
 L   g 
  683.16  2.730 
      0.0765 (maximum at top);
 G   L   540.131  745.6 

∴ Flooding check at top

Csb, flood = 0.27 ft/s

Csb, flood = Capacity parameter (ft/s)

Unf = Gas velocity through net area at flood (ft/s or m/s)

0.2 0.5
 20   g 
Csb, flood = Unf    
    
 L g 

= liquid surface tension= 18.0 N/m

0.2 0.5
 18   745.6  2.73 
Unf = 0.27    
 20   2.73 

= 4.361 ft/s = 1.33m/s

 103

Consider 80% Flooding; Gas velocity, Un= 0.8*Unf = 1.063m/s

G 38948.55(kg / hr )
Volumetric Flow rate of Vapor= 
3600 *  g 3600( s / hr ) * 2.730(kg / m 3

= 3.963 m3/s

Volumetricflow rate of vapor 3.963

Net Area (An) =   3.728m 2
Un 1.063

Lw
Let  0.67 ; Lw= weir length, DC= Column Diameter
DC

2 2
Area of Column (AC) = 0.25 *  * DC  0.785 DC

   L / 2 
sin  C    w   0.67
 2   DC / 2 
 C  83.62 

 2 C Lw DC C 
Area of downcomer (AD) =  4 * DC 360  2 2 cos 2 
 

2
DC
= 0.730  0.5  0.0575DC 2
4

An= AC - AD => 0.785DC2 - 0.0575DC2 = 3.728

DC= 2.263m; DC ≈2.3m

Lw = 0.67*2.263= 1.516m

Lw ≈ 1.5m

AD = 0.0575*(2.263)2

= 0.2945 m2

AC = 0.25 *  * 2.2632  4.0221m 2

An = AC-AD = 4.0221- 0.2945 = 3.7276m2

 104

Active Area (Aa) = AC - 2AD

= 4.0221- 2*(0.2945)

= 3.4331m2

Lw 1.5
  0.652;
DC 2.3
L 
 C  2 arcsin  w 
 DC 
 81.41
ACZ= 2(60mm) * Lw= 0.180m2

A CZ 0.180
  0.0448
AC 4.0221

A CZ  4.5%A C

      180  81.41
 98.59
  2     
   DC  0.06 *
2
Waste zone area, Awz = 2 *  * DC 
 4 360   4 360 

= 2 * 1.1015  1.0439

= 0.1152m 2

A WZ 0.1152
  0.02865
AC 4.0221

Hence, Awz = 2.9% Ac

Area of perforation, Ap = Ac – 2Ad – Acz – Awz

= (4.0221 – 0.589 – 0.18- 0.1152) m2

= 3.1379 m2
 105

Area of holes, Ah = 0.1 Ap

= 0.1 * 3.1379

= 0.3138 m2

4 Ah 4 * 0.3138
Number of holes, nh = 
d h
2
 * (5 *10 3 ) 2

= 15982 Holes

Weir height, hw = 44mm

Weeping Check for the Sieve Tray

pg 2
hd = K1 + K 2 ( )U h (Hobson et al., 1994) where
L

K1 = 0 (for sieve tray); Uh = Linear gas velocity through holes

hd = Pressure drop across dry hole (mm liquid)

50.8
K2  2
; where CV = Discharge coefficient
CV

Area of hole, Ah 0.3138

For   0.0914 ; and
Active Area, Aa 3.4331

Tray Thickness, t T 3
  0.6 ; we have that
Hole Diameter, d h 5

CV = 0.74 (Hobson et al., 1994), then

50.8
K2 =  92.77
0.74 2

Uh = × ×
 106

38948.55
(Uh)top = = 13.579m/s (maximum)
2.539 * 3600 * 0.3138

38948.5
(Uh)bottom = = 12.629 m/s (minimum)
2.730 * 3600 * 0.3138

pg 2 2.539
(hd)top = K2( )U htop = 92.77* ( ) *13.5792
L 744.93

= 58.303 mm of clear liquid

2.730
(hd)bottom = 92.77* ( ) *12.6292 = 54.175 mm of clear liquid
745.6

  
hσ = 409   (Hobson et al. 1994)
 Ldh 

hσ= head loss due to the bubble formation

 18 
hσ= 409*   =1.97 mm of clear liquid
 745.6 * 5 

2
 q 3
Height of crest over weir, hOW = FW * 664 *   where
 LW 

FW = weir constriction correction factor

q = Liquid flow per serration (m3/s)

49262.67
q= =  18.35 *10 3 m 3 / s
× 745.6 * 3600

FW = 1.02 (Hobson et al., 1994)

2
3
 18.35 *10 3
hOW = 1.02*664*    35.96 mm of clear liquid
 1.5 

Head loss due to bubble formation, hσ + Pressure drop across dry hole, hd =

= (1.97 + 54.175) mm = 56.145mm

 107

Height of crest over weir, how + Weir height, hw = 44 + 36 = 80 mm

= 0.0914; hw + how = 80 mm and hd + hσ = 18mm

Since 18mm < 56.145mm, then there is no weeping.

Flooding Check

Since the maximum flow rate occurs at the top, flooding will be checked at the top.

Height of clear liquid over the dispersal, hds = hW + hOW + hhg*0.5 (For sieve trays);

where hhg is the liquid gradient across plate (mm liquid)

(hOW)top = 27.9 mm (from end of rectifying section)

hds = 44 + 27.9 + 0 = 71.9 mm

Linear vapor velocity through active area,Ua=

× ×

38948.55
Ua =  1.241m / s  4.072 ft / s
3600 * 2.539 * 3.4331

ρg = 2.539kg/m3 = 2.539 × 0.0625lb/ft 3 = 0.1587 lb/ft3

Fga = Ua (ρg)0.5 (Hobson et al., 1994)

Fga = 4.072 × (0.1587)0.5 = 1.62

Aeration factor, β = 0.60; Relative frost density, Φt = 0.23

Pressure drop through aerated material, hl1 = β × hds = 0.60 × 71.9 = 43.14 mm

h1 ' 43.14
Actual height of froth, hf =   187.57mm
t 0.23

2
q 
Head loss under the down-comer, hda = 165.2  b  where
 Ada 

Ada = minimum area of flow under the down-comer apron

 108

qb = volumetric flow rate of liquid at the bottom of the stripping section

hap = hds – c = 71.9 – 25 = 46.9 mm

Ada = LW × hap = 1.5 × 46.9 × 10-3 = 0.07035 m2

Lt 49262.67
qb = ×
=   18.37 * 10 3 m 3 / s
 L 3600 * 744.93

2
18.37 * 10 3 
hda = 165.2 ×    11.26mm
 0.07035 

Total head loss across the plate, ht = hd + hl' = 58.303 + 43.14 mm = 101.443mm

Total head loss across the stripping section, hdc = ht + hw + how + hhg + had

= 101.443 + 44 + 36 + 0 + 11.26 = 192.703 mm

Taking relative froth density, Φdc average = 0.50;

192.703
Actual back-up, hdc1 =  385.406mm < 457.2mm
0.5

Since Actual back-up < Tray spacing, i.e. 385.406 mm < 457.2 mm, then it can be said that

flood checking is satisfied, i.e. there is no flooding.

Column Efficiency (Average conditions)

0.5
0.776  0.00457h w – 0.238 U a  g  105 w
Gas phase transfer unit, Ng =
(N sc, g ) 0.5

 g , ave 8.025 * 10 3 * 10 3
Nsc,g = Gas phase Schmidt number = 
 g * Dg 2.635 * 0.148 * 10 4

= 0.206

38948.55
Ua =  1.196m / s
3600 * 2.635 * 3.4331
 109

LW  DC 1.5  2.3
Width of flow path on plate, Df =   1.9m
2 2

q
Liquid flow rate, w = ;
Df

49262.67
q= =  0.01837m 3 / s
× 744.93 * 3600

w= 9.6682 *10 3 m 3 / m  s

(0.776  0.00457* 44) – 0.238 (1.196) (2.635) 0.5  (105 * 9.6682 *10 -3 )
Ng =
(0.206)0.5

Ng = 3.371

Liquid phase transfer unit, NL = KLa × θL, where

KLa = Liquid phase transfer coefficient

θL = Residence time of liquid in froth or spray zone

(DL),average = 4.765 × 10-9

KLa = (DL,avg)0.5(0.40 * Ua * ρvap0.5 + 0.17)

KLa = (3.875 × 108 × 4.765 × 10-9)0.5(0.40 × 1.196 × 2.6350.5 + 0.17)

KLa = 1.286 m/s

hL Aa
θL = , where hL = Liquid hold-up on plate
1000qb

58.303* 3.4331
L   10.90 sec onds
1000 *18.37 *103

NL = 1.286 × 10.90 = 14.01

mtop =0.49; mbottom=1.15

G   Gm  38948.85
Stripping factor at top, λt = 0.49*  m  ;     0.7906
 Lm   Lm  49262.67
 110

λt= 0.49*0.7906 = 0.3874

Stripping factor at bottom, λb = 1.15 × (.7906) = .9092

Average stripping factor, λ = 0.5 * (λt +λb)

λ= 0.6482

1
N og 
1 

N g N liq

1
= = 2.916
1 0.6482

3.371 14.01

EOG = 1 – e –Nog = 1 – e –(2.916) = 0.946

Murphee Plate Efficiency, Emv

Since Residence time, θl = 10.90s which is quite large, then

Emv ≈ EOG = 0.946

Overall Column Efficiency, Eoc

{ ( )}
Eoc = , where Ea = Murphee vapor efficiency
( )

= , where = fractional entrainment

0.5 0.5
L  g  49262.67  2.635 
For G     * 
38948.85  744.93  = 0.0752
 L 

For 80% flooding, using the referenced text, ψ = 0.06

 111

1
Ea = 0.946× ( ) = 0.8921
0.06
1  0.946 *
1  0.06

log(1  0.8921* (0.6482  1)

Eoc = = 0.8687
log(0.6482)

Number of theoretical traysN t 24

Number of actual trays, Na =   27.62  28 trays
EOC 0.8687

Height of stripping section = Number of trays × tray spacing = 28 × 0.4572 = 12.63m

Total height of Column= Enriching Section + Stripping Section

= 13.26 + 12.63= 25.89 m

6.2 Condenser Preliminary Calculations

(a) Heat Balance:

Vapor flow rate (G) = 540.131 kmols/hr

= 497.544 x 72.11 = 38948.85 kg/hr

= 10.82 kg/s

Vapor Feed Inlet Temperature = 64.6oC.

Let Condensation occur under Isothermal conditions i.e FT=1

Condensate outlet temperature = 64.6oC

∴Average Temperature = 64.6oC

Latent heat of vaporization (λ) = 3.15*107 *(0.987) + 3.2*107 (0.013)

= 31506500 kJ/kmol

= 436.923 kJ/kg

qh = mass flow rate of hot fluid * latent heat of hot fluid

 112

qh = heat transfer by the hot fluid

qh = 10.82 x 436.923 = 4727.50 kJ

qC= mass flow rate of cold fluid(mc) x specific heat x ΔT

qc = heat transfer by the cold fluid.

Assume : qh = qC; Inlet temperature of water = 25oC.

Let the water be untreated water.

∴ Outlet temperature of water (maximum) = 40oC

∴ ΔT = 40-25= 15oC

Specific heat, Cp = 4.285 kJ/kg. K

4727.50 * 1000
mc = 4285 * 15 = 73.55 kg/s

(b) Log Mean Temperature Difference (LMTD) Calculations:

Assume: Counter- current

 113

(T1  t 2 )  (T2  t 1 )
(T  t )
ln 1 2
LMTD= (T2  t 1 )

Under Isothermal Conditions; T1 = T2= 64.6oC; t1 =25oC, t2 =40oC

(64.6  40)  (64.6  25)

(64.6  40)
ln
∴ LMTD = (64.6  25) = 31.51 oC

(c) Routing of fluids:

Vapors - Shell side

Liquid - Tube side

(d) Heat Transfer Area:

(i) qh = qC =UA (ΔT) LMTD, corrected

U= Overall heat transfer coefficient (W/m2. K)

Assume: U = 250 W/m2K

4727.50 * 1000
 600.13
∴ A assumed = 250 * 31.51 m2

(ii) Select Pipe Size

Outer Diameter of Pipe (OD) = 0.75” = 0.0191 m

Inner diameter of pipe (ID) =0.620” = 0.0157m

Let length of tube =16 ft = 4.877 m

Let allowance = 0.05m

Heat transfer area of each tube (aheat-transfer) = π x OD x (Length – Allowance)

= π x 0.0191 x (4.877 – 0.05)

 114

= 0.29 m2

A assumed 600.13
  2077.5
∴ Number of tubes (Ntubes) = a heat- transfer 0.29

≈ 2078 tubes

(iii) Fluid Velocity Check:

(a) Vapor side – need not check

(b) Tube side

a pipe x N tubes
N tube passes
Flow area per pass (atube) =

apipe = C.S of pipe = 0.25*π*DI2

Ntubepasses = 6

∴ atube = 0.25 * π (0.0157)2 x 2078/6 = 0.067 m2/pass

m pipe
 pipe * a tube
Velocity of fluid (Vpipe) vp =

mpipe = mass flow rate of fluid in pipe.

ρpipe = Density of fluid in pipe (water)

73.55
 1.10m / s
∴ vp = 994.865 * 0.067

∴ fluid velocity check is satisfied

 115

(iv) Film Transfer Coefficient:

Properties are evaluated at tfilm:

( ) ( )
{ . { .
= = = 80.85℃

a) Shell side:

4 4 W 4 10.82
 * 2
 * 2
  3
0.0004 3
Reynolds’s Number (NRE) = ( N tubes ) * L 2078 * 4.877

NRE= 136

For Horizontal condenser:

1 1
3
1.51 * (D o *  2 g) 3 N RE 3
Nusselt’s Number, Nu = 2

= 182 .92

h o (D o )
Nu = K

ho = outside heat transfer coefficient (W/m2K)

k = Thermal conductivity of liquid.

Nu * K 182.92 * 0.121
ho  
Do 0.0191 ) = 1158.80 W/m2K

b) Tube side:

m
Super icial Mass Velocity, G =
a
 116

73.55
G = = 6586.567 kg/m s
0.067
6

(D )G 0.0157 ∗ 6586.567
N = = = 2.60 × 10
µ 0.4 × 10

µC 0.4 × 10 × 4.285 × 10
Prandtl Number, N = = = 14.17
K 0.121

h (D )
= 0.023(Re . )(Pr .
)
K

implying that h = 53211.22 W/m K

hi = inside –heat transfer coefficient

c) Fouling factor

Take Dirt –coefficient = 0.003 [Perry, 6th Edition]

1 1 Do 1
  *  Fouling Factor
Uo h o DI h i

Uo = overall heat transfer coefficient

1 1 0.0191 1
  *  0.003
U o 1158.80 0.0157 53211.22

Uo =257.35 W/m2K (Recall Uassumed= 250 W/m2K)

Uo > Uassumed; Hence; no fouling.

 117

(v) Pressure Drop Calculations

a) Tube Side :

NRE = 2.6 * 106

Friction factor, f = 0.079 (NRE)-¼ = 0.079 (2.6*106)-¼ =1.967 * 10–3

Pressure Drop along the pipe length ΔPL = ΔHL * ρ * g

4fLVp 2
**g
= 2 * g * D I

4 * 1.967 * 10 -3 * 4.877 * 1.12

* 994
= 2 * 0.0157

= 1.470 KPa

Pressure Drop in the end zones ΔPe = 2.5 ρ* Vp2 = 2.5 x 994 x 1.12 =3.00 KPa

Total pressure drop in pipe ΔPtotal = [1.47 + 3.00] * Number of Passes

= 4.47 * 6 = 26.82 KPa

b) Shell side: Kern’s method

Number of baffles =0

∴Baffle spacing (B) = 4.877 m

C1 = 1”- Do= (2.54 * 10–2 ) – 0.0191 = 0.0063

Pitch, PT = 10* 1” = 25.4*10–2 m

shell diameter * C1 * B 1.219 * 0.0063 * 4.877


ashell = PT 0.254

= 0.1475 m2
 118

 PT 1  2 
 2 * 0.86PT  2 * 4 * D O 
4 
  * DO 
De =  2 

 0.254 1  2 
 2 * 0.86 * 0.254  2 * 4 * 0.0191 
4 
  * 0.0191 
=  2 

= 3.6795m.

m shell 10.82

Gs= Superficial velocity in shell = mshell = a shell 0.1475 = 73.36 kg/m2

G S * D e 73.36 * 3.6795
 3
 3.22 *10 7
(NRE) s =  8.3896 * 10

f = 1.87 (3.22*107) –0.2 = 0.059

 4f ( N b  1) D S G S 2 g 
  * 0.5
 2 gD  
∴ Shell side Pressure Drop ΔPs =  e vapor
; Nb = 0

 4 * 0.059(1) * 1.219 * 73.36 2 

  * 0.5
 2 * 3.6795 * 2.6 
∴ ΔPs =

= 0.0405 KPa
 119

6.3 Summary of Chemical Engineering Design of DC 2

Table 16 below gives an outline of the flow and properties of DC 2. Dimensioned sketch of

the distillation column, reboiler and condenser is given in Fig 12 and 13.

6.4 Notations

F = molar flow rate of feed, kmols/hr

D = molar flow rate of distillate, kmols/hr

W = molar flow rate of residue, kmols/hr

xF = mole fraction of iso-butyraldehyde in liquid

xD = mole fraction of iso-butyraldehyde in distillate

xW = mole fraction of iso-butyraldehyde in residue

Rm = minimum reflux ratio; R = actual reflux ratio

L = molar flow rate of liquid in the enriching section, kmols/hr

G = molar flow rate of vapor in the enriching section, kmols/hr

L = molar flow rate of liquid in stripping section, kmols/hr

G = molar flow rate of vapor in stripping section, kmols/hr

M = average molecular weight of feed, kg/kmols

q = Thermal condition of feed

 120

Table 16: Chemical Engineering Design Properties of Distillation Column (DC) 2

Enriching Section Stripping Section

Tray Spacing 457.2mm 457.2mm

Sieve Hole Diameter 5.000mm 5.000mm

Sieve Hole Pitch 15.000mm 15.000mm

Tray Thickness 3.000mm 3.000mm

Plate Diameter 0.055mm 0.0752mm

Flooding (%) 80 80

Active Area 3.4298m2 3.4331m2

Waste Zone Area 0.1092m2 0.1152m2

Area of Perforations 3.731m2 3.1379m2

Area of Holes 0.3731m2 0.3138m2

Number of Holes 19002 15982

Weir Height 44mm 44mm

 121

Head loss due to Bubble formation 1.78mm 1.97mm

Height of Crest over Weir 28mm 35.96mm

Height of Clear Liquid over dispersal 71.9mm 71.9mm

Head loss under Down-comer 5.42mm 11.26mm

Total Head loss across the Plate 85.104mm 101.443

Total Head loss across the section 162.424mm 192.403

Gas phase transfer unit 2.619 3.371

Residence Time 10.30s 10.90s

Overall Column Efficiency 0.8365 0.8687

Number of Trays in Section 29 28

Height of Section 13.26 12.63

 121

25.89

Fig 12: Dimensioned Sketch of Distillation Column (DC) 2

 122

2.602m

2.602m

REBOILER

CONDENSER

Fig 13: Dimensioned Sketch of Reboiler and Condenser

 124

CHAPTER SEVEN

MECHANICAL DESIGN OF N- AND ISO-BUTYRALDEHYDE

DISTILLATION COLUMN

7.1 Specification Details

7.1.1 Shell

Diameter (stripping section) = 2.3 meters

Operating pressure = 1atm = 1.0329 kg/cm2

Design pressure = 1.1 x operating pressure = 1.1 x 1.0329

=1.1362 kg/cm2

Operating temperature = (74.8oC)

Design Temperature = 1.1 x 74.8= 82.28oC

Shell material: Stainless steel

Shell Double welded bolt joints

stress relieved

Skirt height 4 meters

Tray spacing 457.2mm

Top Disengaging Space 1 meter

Bottom Separator space 2.75 meters

Allowable stress for shell material 950 kg/cm2

Insulation material Asbestos

Insulation thickness 75 mm
 125

Density of Insulation 575 kg/m3

(a) Head: Torospherical Dished Head.

Material Carbon Steel

Allowable tensile stress 950 kg/cm2

(b) Skirt Support

Height 4meters

Material Carbon steel

(c) Nozzles (Number of Nozzles =4)

(d) Trays – Sieve type

Number of trays 28

Spacing 457.2 mm

Hole diameter 5 mm

Thickness 3 mm

Weir height 44 mm

Material for trays down comers weirs Stainless steel.

 126

(e) Calculations of Shell Thickness :

Considering the vessel as an Internally Pressurized (I.P) vessel;

0.5
  PD i 2  
ts =   +C
 2fJ - P  
 

ts = Thickness of shell (mm)

P = Design pressure (kg/cm2) = 1.1362 kg/cm2

Di = Diameter of the shell (cm) = 230cm

f = Permissible tensile stress (kg/cm2) = 950 kg/cm2

C = Corrosion allowance (cm) = 2 cm

J = Joint Efficiency; considering double welded butt joints with backing

strip

J = 85% = 0.85

 1.1362 * 230 2  0.5

t s =   + 2  8.1cm
 2 * 950 * 0.85 - 1.1362 

Hence, thickness of shell= 81 mm

(f) Head Shallow dished & Torospherical Head.

0.5
 PR 2 W 
th   C 
 2fJ 

RC = Crown Radius = Outer diameter of the shell = 2300+ 2(81) = 2462 mm

RK= Knuckle Radius = 0.06 RC= 0.06(2462) = 147.72 mm

 127

W= Stress Intensification Factor

1 RC  1  2462 
W 3    3    1.77
4  R K  4  147.72 

0.5
1.1362 * 246.2 2 * 1.77 
th     8.687cm  87mm
 2 * 950 * 0.85 

∴ Thickness of head is th = 87mm = 3.425 inches

(g) Weight of head:

Wh= Area * Thickness * Density of Material

Area of Head (Circular shape)= 0.25 * π* Diameter

OD 2
Diameter  OD   2S f  i cr
24 3

OD = Outside diameter of shell = 2462 mm = 96.93 inches

icr = inside cover radius = 0.75 inches

Sf = straight flange length = 1.5 inches

95.51 2
Diameter  95.51   2 * 1.5  * 0.75 = 104.5 inches=265.35 cm
24 3

Density of Carbon Steel= 7850 kg/m3= 7.85*10-3kg/cm-3


Weight of Head = * 265.35 2 * 8.7 * 7.85 * 10 3
4

= 3776.74 kg

Weight of Head ≈ 3800 kg

 128

7.1.2 Calculation of stresses

(i) Axial Tensile Stress due to Pressure Fap

PDi 1.1362 * 230

Fap =  = 10.71 kg/cm2
4(t s  c) 4(8.1  2)

This is same throughout the column height

(ii) Circumferential Stress:

2 Fap = 2 x 10.71 = 21.42 kg/cm2

(iii) Compressive Stress due to Dead Loads:

(1) Compressive stress due to weight of shell up to a distance X meters.

Weight of Shell
Fds 
Cross  sec tion Area of Shell

OR,

weight of shell per unit height * X

Fds =
 * Dm * (ts - c)

Dm = Mean diameter of the shell (cm)

ts = thickness of the shell (cm)

C = Corrosion allowance (cm)

Fds = ρs (X)

ρs = 7850 kg/m3

= 0.00785 kg/cm3

Fds = 0.00785X kg/cm2

 129

(2) Compressive stress due to weight of insulation at height (X) meters

 * D ins * t ins *  ins * X

Fd(ins) =
 * Dm * (ts - c)

Dins = Diameter of insulation

tins = Thickness of insulation

ρins = Density of insulation

Dm = Mean diameter of shell = [ DC + ts]

Assume : Asbestos is the insulation material.

ρins = 575 kg/m3 = 0.000575 kg/cm3

tins = 75 mm = 7.5 cm

Dins = DC + 2 * (ts + tins)

Dins = 2300 + 2(81) + 2(75) = 2612 mm = 261.2 cm

Dm = 2300 + 81 = 2381 mm = 238.1 cm

 * 261.2 * 7.5 * 0.000575* X

Fd(ins) =
 * 238.1* (8.1 - 2)

= 7.76*10-4 X kg/cm2

(3) Compressive stress due to liquid & tray in the column up to height (X) meters.

Liquid & tray weight for height (X)

 (x  1)   D i 2
Fliq    1 * *  liq
 tt  4

tt = tray thickness= 0.4572 meters

Di = Internal diameter= 2.3 meters

 130

 liq = Mean Density of liquid

739.58 + 744.930 + 744.930 + 745.60

=  743.76kg/m 3
4

2
 ( x  1)   * 2.3
Fliq    1 * * 743.76
 0.4572  4

= (x - 0.5428)*6758.84 kg

Fliq ( x  0.5428) * 6758.84


Fd(liq) =  * Dm * ( t s  c)  * 238.1 * (8.1  2)

= (x-0.5428)*1.481 kg/cm2

(4) Tensile stress due to wind loads in self supporting vessel

Mw
Fwx 
z

Mw = Bending moment due to wind load

= 0.5* (wind load * distance)

= 0.5* (0.7 PwDmx2)

z = modulus for the area of shell = 0.25 * π * Dm2*(ts - c)

0.5 * (0.7 Pw D m x 2 ) 1.4 * Pw x 2 )

Fwx  2

0.25 *  * D m * (t s - c)  * D m * (t s - c)

Pw = Wind Pressure

= 45 lb/ft2

= 219.42 kg/m2= 0.021942 kg/cm2

Mw = 0.5* (0.7 x 0.021942 x 238.1) x2 = 1.8285 x2

 131

z = π* (238.1)2 *(8.1 – 2)*0.25 = 271605.47 cm2

1.8285x 2
Fwx =  6.73 * 10 6 x 2 kg/cm2
271605.47

Stresses due to seismic load are neglected.

(5) Calculations of resultant longitudinal stress (upwind side )

Tensile:

Ft,max = Fwx + Fap – Fds

Fwx = Stress due to wind load.

Fap = Axial tensile stress due to pressure

Fds = Stress due to dead loads.

Ft,max = 6.73*10-6 x2 + 10.71 – 0.00785x

Ft,max = fJ

f = Permissible stress = 950 kg/cm2

J= Joint factor = 0.85

∴ Ft,max = 950 (0.85 ) = 807.5 kg/cm2

6.73*10-6 x2 - 0.00785x +10.71 = 807.5

6.73*10-6 x2 - 0.00785x - 796.79 = 0

Solving the simultaneous equation

x = 115 meters
 132

(6) Calculation of resultant longitudinal stress (downwind side) (compressive):

Ft,max = Fwx - Fap + Fds

Ft,max = 6.73*10-6 x2 - 10.71 + 0.0077x

 t 
0.125E 
∴ Fc,max =  Do 

E= Elastic modulus (Steel)= 2*105 MN/m2 = 2*106 kg/cm2 (Take g= 10m/s2

ts = Shell thickness = 81mm.

Do = 2462 mm

 81 
Fc,max = 0.125 * 2 * 10 6    8225kg / cm
2

 2462 

6.73*10-6 x2 + 0.00785x - 8235.71 = 0

x= 344 meters

Since calculated height is greater than the actual tower height. So we conclude that the

design is safe and thus design calculations are acceptable.

∴ A thickness of 81mm is sufficient throughout the length of the shell.

7.1.3 Design of skirt support

H, Total height of column including skirt height and disengaging spaces

= 25.89 + 4 + 2.75 + 1 = 33.64m

Minimum weight of vessel (Wmin) = π*(Di+ts)ts * (H- skirt height ) ρs + 2 (Wh)

Di = (internal) diameter of shell = 2.3 meters

ts = 0.081 meters

ρs = Density of material= 7850 kg/m3

 133

Wh= Weight of head= 3700 kg

Wmin = π (2.3 + 0.081) 0.081 (33.64 - 4)* 7850 + 2(3700)

= 148375 kg.

Maximum weight of column (Wmax ) = WS + Wins + Wl + Wa

WS = weight of shell during test = 10800 kg.

Wins = weight of insulation = 0.25* π (d2ins - d2o) Hρins

= 0.25* π*{2.6122 – 2.4622}*33.64* (575)

= 11562.6 kg

Ww = weight of water during test = 0.25* π Di2 (H - 4) ρwater

= 0.25 * π (2.3)2 (33.64 - 4) * 1000

= 123147 kg

Wa = weight of attachments = 7100 kg

Wmax = 10800 + 11562.6 + 123147 + 7100 = 152609.6 kg

Period of vibration at Minimum dead weight

3 0.5
 H 2 W
-5 
Tmin = 6.35 * 10 *    min 
 D   ts 

3
0.5
 33.64  2  148375 
-5
= 6.35 * 10 *    
 2.3   0.081 

= 4.81 secs

Tmax
∴ K2 = a coefficient to determine wind load =
Tmin
 134

Period of vibration at maximum dead weight=

3 0.5
-5 H 2  W 
Tmax = 6.35 * 10 *    max 
 D   ts 

3
0.5
 33.64  2  152609.6 
= 6.35 * 10-5 *    
 2.3   0.081 

= 4.875 secs

4.875
∴ K2 =  1.01
4.81

Total load due to wind acting on the bottom & upper part of vessel

PW = K1 K2 Pw HD

K1 = coefficient depending upon safe factor

= 0.70 (for cylindrical surface )

PW = wind load kg

Pw = wind pressure = 1000 N/ m2 = 100 kg/m2

For minimum weight condition D = Di = 2.3 m

For maximum weight condition D = Dins = 2.612 m

∴ PW, min = 0.7 x 1.01 x 100 x 2.3 x 33.64

= 5470.2 kg

PW, max = 0.7 x 2 x 100 x 2.612 x 33.64

= 6212.5 kg

(a) Minimum and maximum wind moments

MW, min = PW, min * 0.5 H = 5470.2 * 0.5* 33.64 = 92008.764 kg.m
 135

MW, max = PW, min * 0.5 H = 6212.5 * 0.5 *33.64 = 104494.25 kg.m

Fzwm = stress due to wind moment at the base of the skirt.

4 M W, min 4 * 92008.764 22142.53

Fzwm, min = 2
 2
 kg/m2
 *D *t 3.142 * 2.3 * t t

4 * 104494.25 4 * 104494.25 25147.25

Fzwm, max = 2
 2
 kg/m2
*D *t 3.142 * 2.3 * t t

(b) Minimum and maximum dead load stresses.

Fzw = Stress due to Dead loads

Wmin 148375 20532

Fzw, min =   kg/m2
Dt 3.142 * 2.3 * t t

Wmax 152609.6 21118

Fzw, max =   kg/m2
Dt 3.142 * 2.3 * t t

Maximum tensile stress without any eccentric load is computed as follows :

(Tensile) Fz = Fzwm, min - Fzw, min

Fz = f*J

22142.53  20532
95 x 105 x 0.85 =
t

t= 2.0*10-4 m2= 200 mm

Maximum Compressive Load:

(Compressive) Fz = Fzwm, max + Fzw, max

 0.081  25147.25  21118

Fz  0.125E 
 2.3  t
 136

t= 5.25*10-4= 525mm

As per IS:2825-1969, minimum corroded skirt thickness is 7mm, providing 1mm corrosion

allowance, a standard

8mm thick plate can be used for skirt.

7.1.4 Design of skirt bearing plate

Maximum compressive stress between bearing plate & foundation:

Wmax M w , max
FC= 
A Z

A=π (Do-L) *L

L=Outer radius of bearing plate - Outer radius of skirt

z= π*Rm2*L

D o  L
Rm =
Z

A=π (2.462 - L)*L

1

Z=  * D o  L  * L
2

3

Allowable compressive strength of concrete foundation varies from 5.5-9.5 MN/m2

Assume: FC = 5.5x105 kg/m2

152609.6 104494.25
FC   1
 * (2.462  L ) * L
 * D o
2
 L * L 
3

Solving for L, L = 2.383m

∴ 2.463- 2.383= 0.079 = 79 mm is the width of the bearing plate.

 137

3Fc
Thickness of bearing plate tbp = L *
F

FC = maximum compressive load at 0.079 m

FC= 29940 kg/m2

3 * 29940
tbp= 2.383 * = 0.0232 m= 23.2 mm
95 * 10 6

Bearing plate thickness of 23mm is required. As the plate thickness required is larger than

20mm, gussets must be used to reinforce the plate.

Maximum bending moment is bearing plate with gussets

Mmax = - 0.199* FC* L2 = -0.119 x 29940 * (2.383)2 = -20.232 kJ

6 * M max 6 * 20232
tbp=   0.0113m ≈ 11 mm
F F

i.e. If gussets are used at 79 mm spacing then bearing plate thickness of 11 mm will be

sufficient.

(a) Minimum stress between the bearing plate and the concrete foundation.

Fmin=

Wmin M w , min 148375 92008.764

  
A Z  * (2.462  2.383)2.383  * (2.462  02.383) 2 * 2.383

Fmin = 250876.35 – 1969251.11

= -1718374.76 kg/m2
 138

Fmin is negative, ∴ the vessel must be anchored to the concrete foundation by means of

anchor bolts to present overturning owing to the bending moment induced by the wind

load.

Approximate value of load on the bolts is given by; Pbolt* n = Fmin * A

Pbolt = load on one anchor bolt.

n= number of anchor bolts.

A=Area of contact between bearing plate & foundation.

Pbolt * n = +Fmin* π (Do-L)* 0.12

= 1718374.76* 3.14 (0.079)* (2.383)

= + 1015777.682

If hot rolled Carbon Steel is selected for bolts F = 57.3 MN/m2 =57.3 x 105 kg/m2

(ar* n) *F = n* Pbolt

ar* n= 0.01773; ar = root area of bolts

For M16 x 1.5 bolts specs, ar =1.33 x 10-4 m2

n=133; i.e. the number of bolts required is 133.

 139

Fig 14: Sketch of the Second Distillation Column5

5
Detailed Mechanical Drawings included in Appendix A
 140

7.2 Mechanical Design for the Condenser

7.2.1 Shell side

Material: Carbon Steel (Corrosion allowance = 3 mm)

Number of shells =1

Number of passes = 6

Working pressure = 1 atm = 0.101 N/mm2

Design pressure = 1.1 x 0.101 = 0.11 N/mm2

Temperature of the inlet = 64.6oC; Temperature of the outlet = 64.6oC

Permissible Strength for Carbon steel = 95 N/mm2

PD i
ts=
2fJ - P

ts = Shell thickness ; P = design pressure = 0.11 N/ mm2

Di = Inner diameter of shell = 1.219m =1219 mm

f = Allowable stress value = 95 N/mm2

J= Joint factor = 0.85

0.11 * 1219
ts = = 0.831 mm
2 * 95(0.85) - 0.11

Minimum thickness = 3 + 0.831 mm = 3.831 mm (including corrosion allowance)

 141

(a) Head: (Torospherical Head)

PR C W
Thickness of Head, th =
2fJ

where; R = Crown radius = Outer diameter of the shell = 1219 mm

Rk = Knuckle radius = 0.06R= 0.06*1219= 73.14 mm

W = Stress Intensification Factor

√ √
W = (3 + ) = (3 + . ×
) = 1.77

0.11 * 1219 * 1.77

th = = 1.47mm;
2 * 95 * 0.85

Incorporating design factor, th = 1.1 × 1.47mm = 1.617mm

Since for the shell, there are no baffles, tie-nods & spacers are not required.

(b) Flanges

Type: Loose type except lap-joint flange.

Design pressure (p) =0.11 N/mm2

Flange material: IS:2004 –1962 class 2

Bolt steel: 5% Cr-Mo steel.

Gasket material = Asbestos composition

Shell side diameter =1219mm

Shell side thickness =10mm

Outside diameter of shell =1219 + (10 × 2) = 1239mm

 142

(c) Calculation of Gasket Width

0.5
d o  y  Pm 

d i  y  P ( m  1) 

y = Yield stress; m = gasket factor = 2.75

Gasket material chosen is asbestos with a suitable binder for the operating conditions.

Thickness = 10mm

y = 2.60 x 9.81 = 25.5 N/mm2

0.5
d o  25.5  ( 0.11 * 2.75) 
 = 1.0022
d i  25.5  0.11 * ( 2.75  1) 

di = inside diameter of gasket = outside diameter of shell

= 1239 + (10*0.5)

= 1244 mm

do = outside diameter of the gasket

= 1.0022 (1244)

= 1248 mm
. .
Minimum gasket width = = 0.002 m= 2 mm

But minimum gasket width = 6 mm

∴ G = 1.244 + 2 (0.006) = 1.256 m

G = diameter at the location of gasket load reaction

 143

(d) Calculation of Minimum Bolting Area

Minimum bolting area (Am) = Ag =

Sg = Tensile strength of bolt material (MN/m2)

Consider 5% Cr-Mo steel, as design material for bolt

At 64.6oC; Sg= 138 × 106 N/m2

. ×
Am = = 4.375 × 10-3m2
×

(e) Calculation for Optimum Bolt Size

gi = .
= 1.414 go

gi = thickness of the hub at the back of the flange

go = thickness of the hub at the small end = 10 + 2 = 12 mm

Selecting bolt size M18x2

R = Radial distance from bolt circle to the connection of hub & back of flange = 0.027

C= Bolt circle diameter = Di + 2 (1.414go + R)

C= 1.219 + 2 [1.414 (0.0120) + 0.027] = 1.307m

(f) Estimation of Bolt Loads

Load due to design pressure (H) = 0.25 * G 2 * P

= 0.25 * 1.256 2 * 0.11 * 10 6

= 0.1363 * 106N

Load to keep the joint tight under operating condition

Hp = π*G* (2b) * m * p
 144

b = Gasket width = 6mm = 0.006m

Hp = π*(1.256)*(2 x 0.006)* 2.75 x 0.11 x 106 = 0.0143 x 106N

Total operating load (Wo) = H + Hp

= (0.136 × 106 + 0.0143 x 106)N = 0.1506 x 106N

Load to seat gasket under bolt–up condition = Wg.

Wg = π * Gby

= π × 1.256 × 0.006 × 25.5 × 106

Wg = 0.6037 × 106N

Wg > Wo; Hence, Wg is the controlling load

Controlling load = 0.6037 x 106N

Actual flange outside diameter (A) = C+ bolt diameter + 0.02

= 1.307 + 0.018 + 0.02

= 1.345m

Check for gasket width:

Ab = minimum bolt area = 44 x 1.54 x 10-4m2

× . × ×
= = 19.75N/mm2
× . × .

2y = 2 x 25.5 = 51 N/mm2

< 2y, then bolting condition is satisfied

 145

7.2.2 Tube side

Number of tubes = 2078

Outside diameter = 0.0191m; Inside diameter = 0.0157m

Length = 4.877m; Pitch, = 25.4 x 10-3m

Feed = Water.

Working Pressure = 1 atm = 0.101 N/ mm2

Design Pressure = 0.11 N/mm2

Inlet temperature = 25oC; Outlet temperature = 40oC

(a) Flange Moment calculations

For operating conditions,

Wo = W1 + W2 + W3

× ×
Hydrostatic end force on area inside of flange, W1 =

W2 = H - W1

Gasket load, W3 = WQ - H = Hp

B = Outside shell diameter = 1.239m

× . × . ×
W1 = = 0.1326 × 106N

W2 = H - W1 = (0.1363 –0.1326) × 106 = 0.0037 × 106N

W3 = 0.0143 x 106N

Wo = (0.1326 + 0.0037 + 0.0143) x 106

= 0.1506 x 106N

Mo = Total flange moment = W1a1 + W2a2 + W3a3

a1 = ; a2 = ; a3 =
 146

C = 1.307; B = 1.239; G = 1.256

. .
a1 = = 0.034

. .
a3 = = 0.026

. .
a2 = = 0.03

Mo = [0.1326(0.034) + 0.0037(0.03) + 0.0143(0.026)] × 106

= 4.9912 kJ

For bolting up condition

Mg = Total bolting Moment = Wa3

W= Sg

Am = 4.375 × 10-3

Ab = 44 × 1.54 × 10-4 = 67.76 x 10-4 m2

Sg= 138 x 106

( . × . × )
W= × 138 × 106 = 0.7694 × 106

Mg = 0.7694 x 106 × 0.026 = 0.020 MJ

Mg > Mo, therefore, Mg is the moment under operating conditions

M = Mg = 0.020 × 106 J

(b) Calculation of the flange thickness

MCf Y
t2 =
BSFO

Cf = Bolt pitch correction factor =

( )
 147

× × .
Bs = Bolt spacing = = = 0.0310m

n= number of bolts.

Let Cf = 1

SFO = Nominal design stresses for the flange material at design temperature.

SFO = 100 x 106 N

M = 0.020 x 106 J

B = 1.239

.
K= = = = 1.086
.

Y = 24

. × × ×
t= = 0.0622m
. × ×

(c) Tube sheet thickness (cylindrical shell)

tls = Gc

Gc = mean gasket diameter for cover.

P = design pressure.

K = factor = 0.25 (when cover is bolted with full faced gasket)

F = permissible stress at design temperature.

. × . ×
tls = 1.256 ×
= 0.0214m
 148

(d) Channel and Channel Cover

th = Gc , K = 0.3 for ring type gasket

. × . ×
th = 1.256 ×
= 0.0234m

Consider corrosion allowance = 4 mm.

th = 0.004 + 0.0234 = 0.0274 m.

(e) Saddle support

Material: Low carbon steel

Total length of shell: 4.877 m

Diameter of shell: 1239 mm

Knuckle radius Ro= 0.06 × 1.239 = 0.074 m

. × .
Total depth of head (H) = = = 0.214m

Weight of the shell and its contents = 12681.25 kg = W

R = D/2 = 620mm

Distance of saddle centre line from shell end = A = 0.5R = 0.31m

(f) Longitudinal Bending Moment

( )
( )
M1 = QA [1 – ]

Q= L+

. .
= × (4.877 + 4× )
 149

= 32732.42 kg.m

M1 = 32732.42 × 0.31 × [1 –

0.31
+ (0.62 − 0.214 )
(1 − 4.877 )
2 × 4.877 × 0.31
4 × 0.214
1+
3 × 4.877

= 96.703 kg.m

(g) Bending moment at center of the span

( )

M2 = ×[ − ]

( . . )
. × . . × .
M2 = ×[ × . − ] = 28629.58 kg.m
.
× .

(h) Stresses in shell at the saddle

At the topmost fibre of the cross section

f1 = × × ×
(k1 = k2 = 1)

.
= = 1.0096 kg/cm2
× . × .

The stresses are well within the permissible values.

Stress in the shell at mid-point

f2 = × × ×

.
= × . × .
= 296.341 kg/cm2

Axial stress in the shell due to internal pressure

 150

× . × × .
fp = = = 419.031kg/cm2
× × .

f2 + fp = (296.341 + 419.031) kg/cm2 = 715.372 kg/cm2

The sum f2 and fp is well within the permissible values.

Detailed drawings and dimensioned sketches suitable for submission to a drawing office

was done using the Aspen B-JAC software, as shown in Appendix A.

 151

CHAPTER EIGHT

INSTRUMENTATION SCHEDULE AND CONTROL SCHEME

8.1 Background

Process control as an aspect of chemical engineering deals with the design and synthesis of

controllers tasked with the objective aims of achieving specific production rate, safety and

product specification. The design of instrumentation for equipment, vessels, piping and

fittings involves the science and control of systems, which measures and/or regulate

physical quantity/process variables such as flow, temperature, level or pressure.

Instruments include many varied contrivances that can be as simple as valves and

transmitters, and as complex as analyzers.

For the hydroformylation reactor, it is desired to design and analyze the requisite

controllers and instruments to ensure optimal and safe operation. The build- up of the

control system was graphed with Aspen Plus 2006® after the process was studied and the

key variables that need control were identified including the available variables that

could be manipulated. Mathematical simulation was carried out using MATLAB.

The reactor temperature was controlled by manipulating the coolant flow rate around

the reactor. The reactor liquid percent level was controlled by manipulating the flow rate of

the largest liquid boundary stream on the reactor i.e. L. The reactor pressure was controlled
 152

by regulating the flow rate of the gases exiting the system, V. As earlier stated, the reaction

rate is very sensitive to CO/H2 concentrations in the system. It was therefore necessary to

flow-control the entry stream into the reactor. The control and instrumentation diagram is

given in Fig 15.

8.2 Control of the Reactor System Temperature

Process description gives the hydroformylation reactor operating conditions as 1300C and

350bars. This temperature is assumed to be the temperature at which the reaction can

proceed without causing any form of danger or deviation from normal reaction path. A

little change in this can cause the system to function abnormally or out of control. Most

process are automated because of avoiding the risk of human error in the process, thus the

process is automated.

To achieve regulation of this temperature, the coolant flow rate will be controlled using

flow-rate controller (CFC). The valve of the coolant is first specified (described in details

in the next section) to be an air-to-close valve. This is due to the fact that it is anticipated

that when there is an emergency the best action the valve can take is to remain completely

open as this can subdue the abnormal increase in temperature. The temperature controller

used in this case is the PID (_proportional+integral+derivative). The major components are

described in the ensuing sub- sections.

 153

CFC

Fig 15: Control Scheme for Hydroformylation Reactor

Legend:

BPV- Bottoms Product Valve LC- Level Controller

CFC- Coolant Flow Controller PV- Propylene Valve
FC- Flow Controller SGV- Synthesis Gas Valve
HFR- Hydroformylation Flow TC- Temperature Controller
Reactor
 154

8.2.1 Sensor

The sensor is the element that measures the output variable, in this case, the reactor

temperature. Here we make use of the thermocouple which measures the temperature in

volts which corresponds to the signal of the controller. The measured value of the

temperature in volts as related to the actual value is shown by the block diagram below;

The sensor sends this measured value through a transmitter to the controller. Transmitters

are devices that produce an output signal, often in the form of a 0-15DC electrical current

signal, although many other options using current, frequency, pressure etc.

It is assumed that the time constant is so small such that the gain of the transmitter is

assumed to be the transmitter gain Km.

TO (volts )
Thus; Km  ;
PV ( 0 C )

Where; TO (0-15 volts) and PV (80-1800C) is the proposed span.

Hence the gain is;

15  0
Km   0.15
180  80

The transmitter always acts in the ‘direct acting manner’ i.e. as the measured variable

increases there is a corresponding increase in the output signal.

 155

8.2.2 The controller

A PID controller is chosen for operation to eliminate the challenge of runaway temperature

increase by the derivative component and the offset error by the integral component. The

relationship between the error signal and the output signal is given below;

Where Kc= controller gain

 I , D are the integral and the derivative time respectively

α= the derivative filter coefficient which most of the time is assumed to be 1.

The controller is the brain of the system. By simulation tuning process, different values of

these parameters will be used to obtain a reasonable stable response. The corresponding

signal sent out of the controller is sent to the final control element which in this case is the

control valve. The specification of the valve are performed by making reference to charts

such as those of the Masolenean and Fisher chart to obtain a specific size of the valve to be

used. The controller used can compensate for disturbance interference.

HFR vessel temperature was kept at safe operating condition using coolant stream and a

Temperature controller (TC) with Kc = 2 and Ti = 5min.

8.2.3 The control valve

The control valve throttles the flow of fluid through them by making use of the trim. The

major components of the valve are the head, the stem, the body, the trim, the actuator, the

pneumatic entrance hole, and the seat. The valve acts depending on the pressure of air

allowed into the valve pneumatic compartment. The valve used in this case is the air-to-
 156

open valve. In specifying valves the major determinant is the safety requirement. The

diagram below shows the flow of signal to a valve;

Fig 16: A Typical Response of a Valve.

If we fit an air-to-open valve at all locations and all our controllers are proportional

controllers (controllers whose output signal is proportional to the error signal). Our

controller can either be direct acting or reverse acting.

Our controller’s equation will be

( )= + ( ) ( )= ( )− ( )
 157

And our valve equation is

( )= ( ) for air to open valve gain will be positive ( > 0)

Anytime the measured flow rate, temperature or pressure is higher than the preset (we want

it to close the valve either fully or partially) or when measured parameter is below the set

point we want the valve to open more.

If at any time the measured parameter is higher than the set point, the controller error

become negative ( ( ) < 0), the controller output signal increases or decreases depending

on the sign of , in this case we want to reduce our output signal to allow the valve close,

then we chose a reverse acting controller( ℎ > 0)

( )= + ( ) ( )= ( )− ( )

>0 ( )= + ( ) ( )<0

We obtain a decreased output signal and our valve closes a little to regulate the flow and

restore to normalcy.

8.2.4 The cooling process

The process in the case is the cooling process. There is no material balance for this

process but the energy balance is written below;

dT
VC p  FC p (Tinlet  Toutlet ) ;
dt

Where;

 = density of the cooling fluid

V= the volume of the process fluid

 158

F= flow rate of the cooling fluid

Cp= the specific heat capacity of the fluid at constant pressure.

The steady state behavior of the system is at Tss=1300C

8.3 Control Scheme for the Liquid Level within the Reactor

The objective of the level control is to avoid the splashing of the reactants and prevent the

mixing of pure tops from the bottoms. The proposed controller here is the proportional

controller which can tolerate offset. The scheme for the transmitter, valve are the same with

the control temperature system in Section 2.4, but here the Kc dictates the control system

because a proportional controller makes use only of the controller gain only to control the

process.

The level can be controlled by manipulating the flow-rate of the bottoms using an air-to

open valve. The reason for using an air-to-open valve is to disallow the wastage of

materials in the reactor in time of emergency. The valve fails close disallowing the reactant

from escaping from the reactor. The relationship between the error signal of the controller

and the output is given as;

Where e (t) = hsp-h (t);

m= the bias signal; m (t) = the output signal; and

Kc = the controller gain.

 159

This controller allows offset depending on the magnitude of the controller gain which ios

the only controller parameter to be varied in this case.

The mass flow rates of propylene stream and synthesis gas stream going into

hydroformylation reactor (HFR) were controlled by propylene stream valve (PV) and

synthesis gas stream valve (SGV) respectfully using a PID controller of 0.1 Kc (Controller

gain) and 5min integral time for both streams. HFR liquid level was kept at safe fill of 85%

using a bottom product valve (BPV) and a PID level controller (LC) with Kc = 2 and Ti =

10min.

Appendix C gives the simulation graph results of the various controllers (liquid and

temperature) for the hydroformylation reactor, both at start- up time and steady state.
 160

CHAPTER NINE

COST ESTIMATION AND ECONOMICS EVALUATION OF THE PROCESS

9.1 Background

Chemical plants are built to make a profit, and an estimate of the investment required and

the cost of production are needed before the profitability of a project can be assessed. An

acceptable plant design must present a process that is capable of operating under conditions

which will yield a profit. Since net profit equals total income minus all expenses, it is

essential that the chemical engineer be aware of the many different types of costs involved

in manufacturing processes. Capital must be allocated for direct plant expenses, such as

those for raw materials, labour, and equipment. Besides direct expenses, many other

indirect expenses are incurred, and these must be included if a complete analysis of the

total cost is to be obtained. Some examples of these indirect expenses are administrative

salaries, product-distribution costs, and costs for interplant communications.

A capital investment is required for any industrial process, and determination of the

necessary investment is an important part of a plant-design project. The total investment for

any process consists of fixed-capital investment for physical equipment and facilities in the

plant plus working capital which must be available to pay salaries, keep raw materials and

products on hand, and handle other special items requiring a direct cash outlay. Thus, in an

analysis of costs in industrial processes, capital-investment costs, manufacturing costs, and

general expenses including income taxes must be taken into consideration

 161

9.2 Cost Estimate of Plant Equipment

Capital cost estimates for chemical process plants are often based on an estimate of the

purchase cost of the major equipment items required for the process, the other costs being

estimated as factors of the equipment cost. The accuracy of this type of estimate will

depend on what stage the design has reached at the time the estimate is made, and on the

reliability of the data available on equipment costs. In the later stages of the project design,

when detailed equipment specifications are available and firm quotations have been

obtained, an accurate estimation of the capital cost of the project can be made.

The cost estimation technique to be adopted in this report is the Factorial Method

of cost Estimation (Lang, 1948). In this technique, the fixed capital cost of the project is

given as a function of the total purchase equipment cost by the equation:

C f = fL Ce

(1)

where C f = fixed capital cost,

Ce = the total delivered cost of all the major equipment items: storage tanks,

reaction vessels, columns, heat exchangers, etc.,

fL = the “Lang factor”, which depends on the type of process.

For the Fluid type 2- Ethylhexanol type being considered, fL= 4.7. Equation 1 can be used

to make a quick estimate of capital cost in the early stages of project design, when the

preliminary flow-sheets have been drawn up and the main items of equipment roughly

sized as described in the equipment schedule.

 162

9.3 Estimation of Purchased Costs of Equipment (PCE)

The process diagram of the 72000 tons/year 2- Ethylhexanol plant gives an

overview of equipment required for plant installation (Fig 2), as follows;

 Three Units of Reactors (Hydroformylation, Aldol Conversion and Hydrogenation)

 Two units of Gas- Liquid Separators (GLS) 1 & 2

 Two units of Distillation Columns (DC) 1 & 2

 One Cracker Unit

Other ancillary equipment required for plant installation include; One Filter Unit, Five units

of Mixers, Two Valves, One Pump, Two Recycle Units, One Compressor, Two units of

Heat Exchange equipment, a Separator, and storage tanks for feed, intermediate and

product chemicals.

The cost of the purchased equipment is used as the basis of the factorial method of

cost estimation and was determined as accurately as possible. It was also preferably based

on recent prices paid for similar equipment. Cost of equipment was researched online on

http://www.matche.com/equipcost. (Cost index obtained at

http://www.matche.com/equipcost was based on that obtained for the year 2007, hence, the

need for cost index for year 2012). Fig 17 gives the plot of chemical engineering plot

index.
 163

Fig 17: Plot of Chemical Engineering Cost Index

(Source:www.processengineeringmanual.it)

The linear plot equation is given by: y = 32.36x – 64411

At 2007, y = 32.36 × 2007 – 64411 = 535.52 (i.e. cost index at 2007 = 535.52)

At 2012, y = 32.36 × 2012 – 64411 = 697.32 (i.e. cost index at 2012 = 697.32)
 164

The method usually used to update historical cost data makes use of published cost indices.

These relate present costs to past costs, and are based on data for labor, material and energy

costs published in government statistical digests. According to Peters and Timmerhaus

(1991),

Present cost = original cost ( )

.
Hence, Present Cost= Original Cost (in 2007) * ( .
)

Present Cost = Original Cost * 1.302

Hence, we simply multiply each equipment cost obtained

fromhttp://www.matche.com/equipcost by a factor of 1.302 to get its value in year 2012.

The original cost represents the bare vessel cost, and its product with the material and

pressure factor gives the actual vessel cost. Details of method used can be extracted

copiously from Chapter 6 of Coulson & Richardson Chemical Engineering Series (Vol 6,

4th Ed.) by R.K. Sinnott (2005).

For currency conversion, the conversion rate of 1 Dollar = 157.3 Naira; 1 Pound = 251.2

Naira (November, 2012) was utilized.

 165

A. Reactors

(i) Hydroformylation Reactor

Specs: Jacketed & Agitated; Material: Stainless Steel 304; Capacity: 137000 Litres; Atm to

25psi

Original Cost: $401000 (material factor = 1.0, pressure factor = 1.1)

Present Cost= 401000*157.3*1.302 * 1.0 * 1.1= #90,339,331.06k

(ii) Hydrogenation Reactor

Specs: Jacketed & Agitated; Material: Carbon Steel; Capacity: 114522500 Litres; Atm to

25psi Original Cost: $99100 (material factor = 1.0, pressure factor = 1.1)

Present Cost= 99100*157.3*1.302 * 1.0*1.1= #22,325,749.45k

(iii) Aldol Condensation Reactor

Specs: Jacketed & Non- Agitated; Material: Stainless Steel 316; Capacity: 24000 Litres;

Atm to 25psi

Original Cost: $154400 (material factor = 1.0, pressure factor = 1.1)

Present Cost= 154400*157.3*1.302*1.0*1.1= #34,784,013.26k

 166

(iv) Cracking Unit

Specs: Jacketed & Agitated; Material: Low Alloy Steels; Capacity: 6500 Litres; Atm to

25psi Original Cost: $111400 (material factor = 1.0, pressure factor = 1.1)

Present Cost= 111400*157.3*1.302= #25,096,755.68k

B. Gas- Liquid Separators (2 Units)

Specs: Vane Type; 250 psi rating; 240 inches diameter; Material: Carbon Steel 304L and

306L;

Original Cost: $41000 (material factor = 1.0, pressure factor = 1.1)

Present Cost: 41000*157.3*1.302*1.0*1.1*2= #18,473,374.92k

C. Distillation Columns

DC 1: Specs: Weight: 90800kg; Material: Ferritic Stainless Steel 430; No internals, large

Capacity: 158000 Litres

Original Cost: $152400 (material factor = 2.0, pressure factor = 1.1)

Present Cost: 152400*157.3*1.302*2.0*1.1= #68,666,886.29k

Cost of a plate = $650 (material factor = 1.7; Number of plates = 32)

Total cost of plates = $650* 36 * 1.7*1.302 * 157.3= ₦8,147,127

Total cost of column = 68666866.29+8147127= #76,814,013.29k

 167

DC 2: Specs: Weight: 873292kg; Ferritic Stainless Steel 430; Sphere ASME,

large Capacity: 179500 Litres

Original Cost: $177220 (material factor = 2.0, pressure factor = 1.1)

Present Cost: 177220*157.3*1.302*2.0*1.1= #79,850,036.67k

Cost of a plate = $650 (material factor = 1.7; Number of plates = 46)

Total cost of plates = $650* 46 * 1.7*1.302 * 157.3= ₦10,410,217.82k

Total cost of column = 79850036.76 + 10410217.82=

#90,260,254.49k

D. Filter Unit

Specs: Gravity- type; Area: 18.58 m2 ; Material: Carbon Steel; Atm pressure

Original Cost: $103600 (type factor = 0.8, pressure factor = 1.1)

Present Cost: 103600*0.8*1.1*157.3*1.302= #18,671,625.77k

E. Coolers (2 Units)

Specs: Forced Draft; Cooling Load: 0.01 Million BTU/hr; Material: Carbon Steel; Atm

Pressure

Original Cost: $5800 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 5800*0.85*1.0*157.3*1.302 * 2 pieces= #2,019,373.36k

 168

F. Mixers (5 Units)

Specs: Material: Carbon Steel; Capacity: 7570 litres; Atm to 25 psi Internal

pressure

Original Cost: $16640 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 16640*157.3*1.302*0.85*1*5 pieces= #14,483,781.31k

G. Pump

Specs: Centrifugal Inline, API- 610 w/ Motor; 13.94 m2 head; Material:

Cast Iron w/Rubber lining; Mechanical Seal

Original Cost: $13900 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 13900*157.3*1.302*0.85*1.0= #2,419,766.35k

H. Heat Exchange Equipment (2 Units)

Specs: Double Pipe, large; CS Shell Aluminium tube; 13.94 m2 ; 300psi

Original Cost: $18600 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 18600*157.3*1.302*0.85*1.0* 2pieces= #6,475,921.45k

I. Compressor

Specs: Type: Air Rotary Screw; Material: Cast Iron; 125 psi I.R; 200 HP

Original Cost: $5950 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 5950*157.3*1.302*0.85*1= #1,035,799.27k

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J. Reboilers (2 Units)

Specs: Carbon Steel; 23.22 m2; 150 psi I.R

Original Cost: $17300 (type factor = 0.8, pressure factor = 1.0)

Present Cost: 17300*157.3*1.302*0.8*1.0* 2pieces= #5,668,991.33k

K. Condensers (2 Units)

Specs: Vertical tube small, 32.52 m2 ; Carbon Steel; 300 psi I.R.

Original Cost: $20200 (type factor = 0.8, pressure factor = 1.0)

Present Cost: 20200*157.3*1.302*0.8*1.0*2 pieces= #6,619,284.67k

L. Storage Tanks

 Hydrogen Tank: Horizontal, Fuel Storage, 20000 gallons Capacity;

Cast Iron

Original Cost: $6, 900 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 6,900*157.3*1.302*.85*1.0= #1,201,179

 Propylene Feed Tank: API Floating Roof, Carbon Steel, 25000

gallons capacity

Original Cost: $9,200 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 9,200*157.3*1.302*.85*1.0= #1,601,572

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 Synthesis Gas Feed Horizontal Round Ends; 40000 gallons capacity;

Carbon Steel & API

Original Cost: $7, 600 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 7,600*157.3*1.302*.85*1.0= #1,323,037.72k

 2- Ethylhexanol Storage Tank Vertical Cone, Floating Roof, Flat

Bottom, 40000 gallons capacity, Carbon Steel & glass lined API

Original Cost: $8, 400 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 8,400*157.3*1.302*.85*1.0= #1,462,304.84

8 Pieces of Tanks for Intermediate Chemicals (Purge Streams, 2- ethyl hexanal, etc)

Each: 30000 gallons capacity, cast iron, Horizontal fuel storage

Original Cost: $4, 300 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 4,300*157.3*1.302*.85*1.0* 8 pieces= #5,988,486.50k

Total Cost of Storage Tanks= #11,576,580.10k

M. Recycles (2 Units)

Original Cost: $1,750 (type factor = 0.85, pressure factor = 1.0)

Present Cost: 1750*0.85*1*157.3*1.302*2 pieces=

#609,293.685k
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N. Valves (2 Units)

Original Cost: $1430

Present Cost: 1430*0.85*1*157.3*1.302*2 pieces=

#497,879.98k

Table 14 gives the summary and cumulative total cost of purchased equipment.

PCE is valued at Four Hundred and Twenty Eight Million, One Hundred and Seventy

One Thousand, Seven Hundred and Eighty Nine Naira Only.

9.4. Estimation of Total Investment Cost

9.4.1 Direct costs

Table 2 presented the range of percentages for estimation of fixed capital

investment costs. Total investment cost comprises of both direct and indirect costs and

typical factors for estimation of project fixed capital cost as given in table below (R.K.

Sinnott, 2007) is reproduced and utilized for this report.

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Table 17: Total Purchase Cost of Equipment Items (PCE)

Item: PCE (Naira)

Hydroformylation Reactor 90,339,331.06

Hydrogenation Reactor 22,325,749.45

Aldol Condensation Reactor 34,784,013.26

Cracking Unit Reactor 25,096,755.68

Gas- Liquid Separators 1 & 2 18,473,374.92

DC 1 76,814,013.29

DC 2 90,260,254.49

Filter Unit 18,671,625.77

Coolers (2) 2,019,373.36

Mixers (5) 14,483,781.31

Pump 2,419,766.35

Heat Exchange Equipment (2) 6,475,921.45

Compressor 1,035,799.27

Reboilers (2) 5,668,991.33

Condenser (2) 6,619,284.67

Storage Tanks 11,576,580.10

Recycles (2) 609,293.68

Valves (2) 497,879.98

Total Purchase Cost of Equipment: 428171790

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Total Physical Plant Cost (PPC) or Direct Costs is given by

PPC= PCE (1 + f1+f2+………+f9)

= PCE (1+0.4+0.7+0.2+0.1+0.15+0.5+0.15+0.05+0.15)

= PCE (3.4)

PPC= 428171790 *3.4

= #1,455,784,086

The Total Physical Plant Cost or Direct Cost is valued at One Billion, Four Hundred

and Fifty Five Million, Seven Hundred and Eighty Four Thousand, Eighty Six Naira

Only.

Table 4 below gives the breakdown of estimated direct costs of the plant using the factorial

method.

9.4.2 Indirect costs

These represent expenses which are not directly involved with material and labor

of, and actual installation of complete facility. By the factorial method, indirect costs is

obtained by factorial multiplication of direct costs, as given below;

Indirect Costs= PPC ( f10+f11+f12) where

Indirect costs = 1445784086 (0.30 + 0.05 + 0.10)

= #650,602,838.70k
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Table 18A: Estimated Direct Costs (PCE)

S/N Item: fi Cost= (Naira)

1 Equipment erection/ Installation 0.40 171,268,716

2 Piping 0.70 299,720,253

3 Instrumentation 0.20 85,634,358

4 Electrical 0.10 42,817,179

5 Buildings, process 0.15 64,225,768.50

6 Utilities 0.50 214,085,895

7 Storages 0.15 64,225,768.50

Site Development 21,408,589.50

8 Ancillary Development 0.05 64,225,768.50

9 0.15

Total Physical Plant Cost: 3.4 1,445,784,086

Table 18B: Estimated Indirect Costs

S/N Item: fi Cost= (Naira)

10 Equipment erection/ Installation 0.30 433,735,225.80

11 Piping 0.05 72,289,204.30

12 Instrumentation 0.10 144,578,408.60

Total Indirect Cost: 0.45 650602838.70

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Fixed Capital Investment (FCI) = Direct Costs + Indirect Costs

= 1445784086 + 650602838. 70

= #2,096,386,925

Working Capital (10-20% of Fixed Capital Investment)

Consider the Working Capital = 15% of Fixed-capital investment of fixed capital to cover

cost of the initial solvent charge.

i.e., Working capital = × 2096386925 = #314,458,038.70

Total Capital Investment (TCI)

Total capital investment = Fixed capital investment + Working capital

= 1.15 * 2096386925= #2,410,844,963

Start Up Cost is usually 5-20% of TCI. Assume 15% of TCI

Start- Up Cost= 0.15 * 2410844963

= #361,626,744.50k

9.5 Estimation of Total Production Cost

Manufacturing Cost = Direct production cost + Fixed charges + Plant overhead cost.

a. Fixed Charges (10-20% total product cost)

(i) Depreciation: Depends on life period, salvage value and method of calculation-

about 10% of FCI for machinery and equipment and 2-3% for Building Value for

Buildings)
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Using Depreciation = 10% of FCI for machinery and equipment and 3% for

Building Value for Buildings)

Depreciation = ∗ 2096386925 + ∗ 64225768.50 = #211,565,465.60

(ii) Local Taxes (1-4% of Fixed Capital Investment) (remitted to Rivers State

Government)

Using local taxes = 3% of fixed capital investment

Local Taxes = ∗ 2096386925 = #62,891,607.75

(iii) Insurances (0.4-1% of Fixed Capital Investment)

Using Insurance = 1% of fixed capital investment

Insurance = ∗ 2096386925 = #20,963,869.25

(iv) Rent: (8-12% of value of rented land and buildings)

Using Rent = 10% of value of rented land and buildings

= ∗ 21408589 + ∗ 64225768.50 = #8,563,435.75

Therefore, Fixed Charges = 211,565,465.60 + 62891607.75 + 20963869.25 +

8562435.75) = #303,984,378. 40

b. Direct Production Cost (about 60% of total product cost)

Fixed charges = 10-20% of total product charges

Consider the Fixed charges = 15% of total product cost

Total Product Cost (TPC) = * 303984378.40 = #2,026,562,522

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(i) Raw Materials (10-50% of total product cost)

Using Raw material cost = 25% of total product cost

Raw material cost = ∗ 2026562522 = # 506,640,630.60

(ii) Operating Labour (OL) (10-20% of total product cost)

Using Operating Labour = 12% of total product cost

Operating labour cost = ∗ 2026562522 = #243,187,502.7

(iii) Direct Supervisory and Clerical Labour (DS & CL) (10-25% of OL)

Using Direct supervisory and Clerical labour = 12% of OL

Direct supervisory and Clerical labour cost = ∗ 243187502.7 = #29,182,500.32

(iv) Utilities (10-20% of total product cost)

Using Utilities cost = 12% of total product cost

Utilities cost = ∗ 2025652522 = #243,187,502.70

(v) Maintenance and repairs (M & R) (2-10% of FCI)

Using Maintenance and Repair cost = 5% of fixed capital investment

Maintenance and Repair cost = ∗ 303984378.40 = #15,199,218.92

(vi) Operating Supplies: (10-20% of M & R or 0.5-1% of FCI)

Using Operating supplies cost = 15% of Maintenance & Repairs

Operating supplies cost = ∗ 1519921892 = #2,279,882.84

(vii) Laboratory Charges: (10-30% of OL)

Consider the Laboratory charges = 30% of OL

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Laboratory charges = ∗ 39906000 = #243187502.7= #72,956,250

(viii) Patent and Royalties (0-6% of total product cost)

Using Patent and Royalties cost = 3% of total product cost

Patent and Royalties = ∗ 2026562522 = #60,796,875.66

Thus, Direct Production Cost = # (506640630.60 + 243187502.70 + 29182500.32 +

243187502.70 + 15199218.92 + 2279882.84 + 72956250 + 60796875.66) =

#1,171,378,464

c. Plant overhead Costs:

(50-70% of Operating labour, supervision, and maintenance or 5-15% of total product

cost); includes for the following: general plant upkeep and overhead, payroll overhead,

packaging, medical services, safety and protection, restaurants, recreation, salvage,

laboratories, and storage facilities.

Using Plant overhead cost = 60% of OL, DS & CL, and M & R

Plant overhead cost = * (243187502.70 + 29182500.32 +15199218.92) =

#172,541,533.20

Thus,

Manufacture cost = Direct production cost + Fixed charges + Plant overhead costs.

Manufacture cost = 1171378464 + 303984378.40 + 172541533.20= #1,647,904,375

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General Expenses = Administrative costs + distribution and selling costs + research

and development costs

1. Administrative costs:

(about 15% of costs for operating labour, supervision, and maintenance or 2-6% of total

product cost); includes costs for executive salaries, clerical wages, legal fees, office

supplies, and communications.

Using Administrative costs = 15% of OL, DS & CL, and M & R

Administrative costs = * (243187502.70 + 29182500.32 +15199218.92) =

#43,135,383.30

2. Distribution and Selling costs:

(2-20% of total product cost); includes costs for sales offices, salesmen, shipping, and

advertising.

Using Distribution and Selling costs = 11% of total product cost

Distribution and selling costs = * 2026562522 = #222,921,877.40

3. Research and Development costs: (about 5% of total product cost)

Using Research and Development costs = 5% of total product cost

Research and development costs = × 2026562522 = #101,328,126.10

4. Financing (interest): (0-10% of TCI)

Using Interest = 5% of total capital investment

Interest = × #2410844963 = #120,542,248.20

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General Expenses = 43135383.30 + 222921877.40+ 101328126.10 + 120542248.20

= #487,927,635

Total Product Cost = Manufacturing cost + General Expenses + Start- up

Cost

= 1647904375 + 487927635 +362626744.5

= #2,497,458,754

9.6 Profitability Analysis

By market survey (http://alibaba.com/products/2_ethyl_hexanol.html), the international

selling price of 2-ethyl hexanol is about 0.38 U.S Dollars per lb= $0.837 per kg

For 72,000 tonnes, total quantity in kg is 72,000,000

At 0.95 percent purity= 72000000* .95= 6.84 * 107 kg 2- ethylhexanol

Hence, Total Income = 0.83 * 157.3 * 6.84* 107

= #8,930,235,600

Gross Income= Total Income- Total Product Cost

= 8930235600 – 2497458754

= #6,432,776,846

Assume Taxes (local, state, national) = 20% of Gross Income

Tax = 0.20 * 6432776846

= #1,286,555,369

Net Profit = Gross Income – Tax

= #6,432,776,846 - #1,286,555,369
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= #5,146,221,476

Hence, a net profit of Five Billion, One Hundred and Forty Six Million, Two Hundred and

Twenty One Million, Four Hundred and Seventy Six Naira is estimated on the 72,000

tonnes capacity per year 2- Ethylhexanol plant.

Pay-back period= ( )

= ( . )

= 0.45 Years ≈ 6 months

Rate of return = * 100%

= 100%

= 213.5 %
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CHAPTER TEN

PLANT START- UP AND OPERATING PROCEDURES

10.1 Background

All industrial plants require an extensive set of operating procedures which define the steps

required - for example - to start the plant up, to shut the plant down, to isolate pieces of

equipment for maintenance or to deal with emergency situations. In older plants, all of

these steps are carried out manually by human operators and are usually officially

documented in a multi-volume set of manuals in the control room, while in highly

automated modern plants the lower-level and more detailed steps are embodied in the plant

control system. It is clearly vital for reasons both of safety and efficiency that procedures

are of a high quality and therefore much effort goes into their generation and subsequent

maintenance. Fig 18 represents the main stages in the design, construction and running of

a chemical plant. It can be seen that operating procedures are a consideration at several

different points within this. At the design stage, where the process is first described at a

high level in Process Flow Sheets, and then in more details as Engineering Line Diagrams

(ELDs), they may form an implicit element of the design rationale - that is, the reasoning

lying behind the specific design decisions made. A designer will clearly avoid design

decisions that they perceive will produce inoperable plant.

When the design is evaluated for safety and operability at the HAZOP stage, some of this

rationale may be drawn out as part of the HAZOP process, but investigation conducted

during the project suggests that it is unusual for operating procedures to be documented in
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Fig 18: The Plant Life- Cycle

 184

any formal and systematic way at this stage. An output of the HAZOP exercise may consist

of operating constraints as well as design changes, but in the case of the chemical process

industry, a multi-disciplinary commissioning team is normally responsible for defining the

detailed sets of operating procedures for a plant alongside their other commissioning work.

This is often a substantial exercise taking around two man-years of effort, and usually

overlaps with the construction of the plant.

A consequence is that if operability problems are uncovered during this process, as may

happen, they may force late changes to the design of the plant. If this occurs while the plant

is actually being constructed it is clearly undesirable and costly. Thus there is an advantage

in considering operating procedures in a more systematic way and earlier than at present.

This is an important motivation for the development of computer-based tools to aid in the

authoring of operating procedures at the pre-HAZOP stage of the life-cycle.

Once the plant is running, operating procedures may need modification in the light of

actual operations experience. If mechanisms for doing this in a controlled way do not exist,

there is a risk of operations practice diverging noticeably from the documented procedures.

A further source of change is modification of the plant whether as a result of maintenance

and repair or of continuous improvement methodologies. The application of computer-

based tools offers the means of reconciling the need for flexibility in the construction and

modification of plant operating procedures with the need for accuracy, consistency and

accountability for changes.

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10.2 General Principles

Commissioning Procedures document a logical progression of steps necessary to verify that

installed plant is fully functional and fit for purpose. A general sequence of steps in

commissioning the 72,000 tons capacity 2- EH plant will typically include:

 System Configuration Check;

The purpose of this activity is to trace all pipework and connections to verify the system

configuration and to visually inspect items of equipment to ensure that they are clean,

empty and fit for purpose as appropriate prior to undertaking water trials.

 Instrumentation System Check - Verification of Alarms and Trips;

The purpose of this activity is to ensure that all instrumentation, alarm settings,

microprocessor signals and hardwire trips pertaining to the installation are functional. This

will also check that signals from the field instrumentation are displayed locally and are

being correctly relayed to the computer interface rack, as well as to the computer system.

 Flushing and Cleaning of Lines and Vessels with Water;

The purpose of this activity is to clean all items of pipework and the vessels that make up

the installation. This task shall also ensure that there are no obstructions, blockages or any

potential contaminants in any of the process lines or vessels that may have resulted from

materials being left inside the system from the construction phase. If chemicals

incompatible with water are to be used, it is important that the pipelines and equipment are
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thoroughly dried prior to introduction of the chemicals. This will be done by passing dry air

through the plant.

 Assessment of Ancillary Equipment;

The main aim of this assessment is to verify the performance of all ancillary equipment.

This may include pumps, fans, heat exchangers, condensers (See Table 4)

 Calibration of Vessels and Instrumentation;

The purpose of this activity is to check the calibration and performance of all vessels and

instrumentation pertaining to the installation. To a certain extent this will be carried out in

conjunction with the system pre-checks to ensure that the correct set points and alarm

points have been established for use in the water trials.

 Chemical Trials;

The aim of this activity is to verify the performance of the installation by simulating ‘live’

conditions by following standard procedures.

 Start Up Protocol;

The purpose of this procedure is to provide guidance for bringing the installation online

starting from an empty non-operational system.

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 Shut Down Protocol;

The purpose of this procedure is to provide guidance for taking the installation offline

starting from a fully operational system.

A Critical Path Network (Plan) with written procedures with related documents are

required. These should define for the facility, each plant system: The order in which the

systems will be started up; Individual activities at each stage; Operation testing

requirements; Durations, waiting times, cooling times; Total duration for starting up each

system; Resources required - labour, materials, equipment, services; Temperatures,

pressures, fluid flows used.

There have been numerous recorded incidents where failings by operators have been the

major contributing cause of major accidents. Provision of clear, concise and accurate

operating procedures is the most effective measure to prevent, control and mitigate such

events. Operating procedures should clearly lay down instructions for operation of process

plant that take into consideration COSHH, manual handling, permit to work, PPE

Regulations, quality, HAZOP, and HSE requirements. The procedure should represent a

definition of good or best practice that should be adhered to at all times. Process operatives

should be provided with guidance concerning the required operating philosophy to ensure

that they comply with procedural requirements.

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Comprehensive written operating procedures should be generated where applicable that

address: Standard operating procedures and operating philosophy; Abnormal operating

procedures; Temporary operating procedures; Plant trials; Emergency operating

procedures; Commissioning; Plant Start-up; Plant Shut-down; Bulk loading and unloading;

Process change; Plant Change.

Standard operating procedures may be revised for the following reasons:

 Introduction of new equipment into the process;

 Introduction of new chemicals into the process;

 Significant change to process, task, personnel or equipment covered by the

procedure;

 Plant trials have been successful and need to be incorporated into standard

operating procedures.

Clear demarcation of where limits of intervention cease and reliance upon the control

systems interface begins is a critical step in defining the operating procedures for a given

plant or process. During the hazard and operability stage, the justification of reliance upon

human intervention rather than automated systems should be established. These are

assessed in more depth in a risk assessment.

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For some specific plant items, start-up is known to present particular additional hazards,

such as;

 Vessels, Tanks, Reactors – ignition of flammable vapours introduced may occur for

systems relying on elimination of oxygen to prevent explosions, unless inert gas

purging is carried out effectively;

 Reactors – start-up of batch reactors after agitator failure may cause an

uncontrollable exothermic reaction.

The start-up and shut-down procedures should be ordered and phased so that interlinked

plant operations can resume or cease in a safe and controlled manner.

Emergency procedures

Any potential deviations to normal operation that cannot be addressed by design or control

identified in the Hazard and Operability studies should be covered by emergency

procedures. These should detail how to make plant and process safe, minimising risks to

operators at all stages. They should cover PPE, the level of intervention which is safe and

when to evacuate. The procedures will need to tie in closely with the on and off-site

emergency plans provided under COMAH.

Management / supervision

A clear management structure should be in place that defines competent responsible

person(s) for generation of operating procedures and supervision of plant and personnel.

The role of the supervisor in terms of training of operators, overseeing certain critical
 190

operations and checking of logs and other activities to ensure compliance with operating

procedures. This should fulfil the requirements of the company’s health and safety policy.

10.3 Start- Up

Commissioning shall start from the point at which steps are taken to bring the Unit/facility

up to operating pressure and temperature and to cut in the feed. It shall be complete when

the Unit/facility is operating at design capacity and producing products to specification.

Due to the interdependence of some plant units, it is imperative from a process point of

view to commission utilities and some of the Units in advance of others, and the sequence

of commissioning is to be determined in the earliest stages of a project.

General requirements as outlined in a chosen Engineering Standard for testing of

equipment/lines shall be followed. The detail procedures for testing of equipment and lines

and other pre-commissioning steps which are not included in such Standard shall be

prepared in accordance with the Company’s Engineering Standards by the Contractor and

submitted to the Company for approval.

Spades, blanks and other equipment installed for testing shall be removed on completion of

testing. Wherever a flange joint is broken after testing, e.g. on heat exchangers, pipe- work,

fired heaters and at machinery, then the joint rings or gaskets must be renewed. Particular

attention must be given to heat exchangers employing solid metal or filled gaskets, and

great care should be taken to ensure that all gaskets renewed after testing of heat
 191

exchangers and are correctly fitted before tightening flanges. Where required, valves are to

be repacked with the appropriate grade of material.

Any temporary bolting which has been used shall be replaced and any temporary fittings

which may have been installed to limit travel, e.g., in expansion joints and pipe hangers,

shall be removed. On completion of testing, vessels, equipment and piping should be

vented and drained, and where necessary cleaned and dried

Prior to commissioning, each item of equipment should have its name, flow-sheet number

and identification number painted and/or stamped on it according to the Specifications

highlighted in the P& IDs.

10.3.1 Preparation prior to initial start-up

The procedures described in this Section shall be carried out at the completion of

construction and before initial operation of the Unit. Appropriate phases should be repeated

after any major repair, alteration, or replacement during subsequent shutdowns. The phases

of preparation for initial start-up shall be according to the following steps:

- Operational checkout list.

- Hydrostatic testing.

- Final inspection of vessels.

- Flushing of lines.

- Instruments.

- Acid cleaning of compressor lines.

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- General notes for Dry-out and boil-out.

- Catalyst loading.

- Tightness test.

10.3.1.1 Operational check-out

a) Check line by line against flowsheet and locate all items. (Every line must be walked!

Physically sight everything)

b) Identify the location of instruments.

c) Indicate the location of all critical valves including valves at critical vent and drain

locations.

d) Check control valves, valves, and globe valves to see that they are installed properly

with respect to flow through their respective lines. Special attention must be given to check

valves regarding their direction of flow.

e) Review all piping and instrument connections for steam tracing.

f) Check that the following facilities have been installed so that the plant can be

commissioned and put on stream: Start-up bypass lines, Purge connections, Steam-out

connections, Drains, Temporary jumpovers, Blinds, Check valves, Filters and Strainers,

Bleeders, et cetera.

g) Check pumps and compressors for start-up.

h) Check sewer system for operability.

i) Check blowdown systems.

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10.3.1.2 Hydrostatic testing

Hydrostatic pressure testing of the Units shall be performed to prove strength of the

materials and weld integrity after completion of the construction. The tests shall be made

on new or repaired equipment and pipings. Detail procedure for testing the equipment and

lines are to be prepared and documented. Fresh water containing a corrosion inhibitor shall

be used for hydrostatic test purpose unless otherwise specified in the Engineering Standard.

In systems where residual moisture cannot be tolerated, and where certain catalysts are

used, oil is the preferred test medium. If the water has to be used, the system should

afterwards be dried out with hot air. Special attention should be given to the points where

water may be trapped, such as in valve bodies or low points. If for any reason it is not

practical to carry out a hydraulic test, a pneumatic or partially pneumatic test may be

substituted subject to conformability to Standards

a) If the piping and equipment metal temperature never exceeds 50°C during

commissioning, operation or nonoperation, water containing up to 30 ppm (by mass)

chlorides ion shall be used. b) If the piping and equipment metal temperature exceeds 50°C

during commissioning, operation or nonoperation, the piping shall be tested using

condensate water, demineralized water or oil with minimum flash point of 50°C.

The testing medium should not adversely affect the material of the equipment or any

process fluid for which the system has been designed. Reference should be made to the

applicable codes in the case of pressure vessels to determine the minimum ambient and

fluid temperatures at which testing may be carried out. If it is desired to test vessels, tanks
 194

or piping at temperatures below 16°C, attention shall be made to the danger of brittle

fracture occurring in carbon steels and ferritic alloy steels unless the materials have

adequate notch ductility properties. For any equipment or piping, water should not be used

for testing, when either the water temperature or the ambient temperature is below 5°C.

Hydrostatic testing at temperatures below this value may be carried out using gas oil,

kerosene or antifreeze solution at appropriate strength

During the hydrostatic test pressure with water the system loss should not exceed 2% of the

test pressure per hour unless otherwise specified. Evidence of water at valves, flanges, etc.

will indicate the leaking areas to be repaired if the system fails the test. All welds and

piping must be inspected for defects by looking for wet spots, therefore they should be

tested before they are insulated.

If piping is tested pneumatically, the test pressure shall be 110% of the design pressure.

Any pneumatic test shall be increased gradually in steps, allowing sufficient time for the

piping to equalize strains during the test. All joints welded, flanged or screwed shall be

swabbed with soap solution during these tests, for detection of leakage. Vents or other

connections shall be opened to eliminate air from lines which are to receive hydrostatic

test. Lines shall be thoroughly purged of air before hydrostatic test pressure is applied.

Vents shall be open when systems are drained so not to create buckling from a vacuum

effect. Relief valves must be removed or blinded prior to hydrostatic testing. After

completion of hydrostatic testing, all temporary blanks and blinds shall be removed and all

lines completely drained. Valves, orifice plates, expansion joints and short pieces of piping

which have been removed shall be reinstalled with proper and undamaged gaskets in place.
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Valves which were closed solely for hydrostatic testing shall be opened. After lines have

been drained with vents open, temporary piping supports shall be removed so that

insulation and painting may be completed.

At the conclusion of the test, the system must be drained. If pumps have been included,

they must each be drained and refilled with oil to prevent rust forming in the seals. If

fractionating columns are included, the water must be displaced with sweet gas, nitrogen,

or an inert atmosphere rather than air to avoid corrosion and sticking of the valves on the

fractionating trays.

Only the following pressure tests should be carried out on heat exchangers;

a) On floating head shell and tube type exchangers, on tube side with bolted bonnets

removed.

b) On tube-in-tube types, on both sides in conjunction with associated pipework.

c) On air-cooled types, the bundles are to be isolated and tested separately from associated

pipe- work.

After completion of test all equipment must be thoroughly drained and if necessary, dried

out to prevent scaling of tubes before commissioning.

All tanks shall have bottoms, shells and roofs tested in accordance with API 650, latest

edition. Shells shall be tested by filling tanks with water. Vacuum testing shall be used for

all tank bottoms and roofs. Flame arrestors and other miscellaneous equipment that does

not have test pressure indicated shall be isolated from the test.
 196

Certain types of instruments with their connecting process lead pipelines shall be tested at

the same pressure as the main pipelines or the equipment to which they are connected.

Such instruments normally include the following types: Displacer type level instruments,

Gage glasses, Rotameters, Control valves, Flow meter pots.

Other types of instruments shall not be tested at line pressure, but shall have process lead

lines tested to the first block valve or valves nearest the instrument. Care shall be taken that

this equipment is protected by removal, or by blocking the instrument lead line and

disconnecting or venting the instruments. These types will normally include the following:

Analyzers, Diaphragm, Type Level Instruments, Differential Pressure Type Flow

Instruments, In-Line Type Flow, Switches, Direct Connected Regulators, Open-Float Type

Level Indicators and Alarm Switches, Positive Displacement Type Flow Meters, Pressure

Indicators Recorders and Transmitters, Pressure Switches, Pressure-Balanced Control

Valves, Pressure Gages, Turbine Type Flow, and Sensors.

Special precautions shall be taken to insure that instruments and instrument lead lines to be

tested are vented and completely filled before testing, and are thoroughly drained after test.

10.3.1.3 Final inspection of vessels

Before the final bolting of coverplates and manholes, vessel interiors should be inspected

for cleanliness, completeness, and proper installation of internal equipment. Inspection list

shall include at least the following items where applicable:

a) Tray installation; satisfactory testing (where required).

 197

b) Internal drawoff piping.

c) Catalyst supports and screens.

d) Internal distributors.

e) Liquid entrainment separators.

f) Internal risers and vortex breakers.

g) Thermowell location and length.

h) Level instruments, location and range, internal float, external displacement and

differential pressure type.

i) Internal cement lining.

10.3.1.4 Flushing of lines

All fluid handling equipment particularly piping, should be thoroughly cleaned of scale and

the internal debris which accumulates during construction. This is accomplished by

blowing or washing with air, steam, water and other suitable medium.

Some utility systems, such as water and high pressure steam, may be satisfactorily cleaned

with their normal media, introduced through normal channels. Other systems must, or

preferably should, be flushed with foreign media, admitted via temporary hose or pipe

connections. Thus, flushing may be accomplished on exhaust steam lines with high

pressure steam or air, and on fuel oil lines with steam, followed by air. The best way to

clean a typical utility or auxiliary system is to flush the supply main from source to end at

first and making an end outlet by breaking a flange or fitting if necessary, than flush each

lateral header in the same manner; and finally, flush the branch which takes off from the
 198

headers. In some instances if required the weld-cap on the end of each header could be cut

off and re-welded after the line has been flushed.

Steam piping

Before blowing a steam line for cleaning, an open end for a free passage of the steam and

debris shall be provided. If the open end is a temporary provision, be certain the end is tied

down to prevent possible whipping caused by high velocity flow. All drains must be open

and the line free of water. Valving to steam traps shall be closed and the traps shall remain

out of service until the line cleaning is completed. Prior to starting stream flow all safety

precautions shall be taken. The area should be cleaned and guarded to prevent injury to

personnel. Steam shall slowly be introduced from the source and the line heated gradually.

The steam flow rate shall be limited to the condensate drainage flow rate. Condensate must

not be permitted to accumulate in order to avoid water hammer. As the piping heats and the

condensate diminish, the steam rate shall be increased. As the line heats, observe its

expansion and determine that there is no binding or distortion. After the piping is

thoroughly heated, the steam rate shall be increased to provide a hard blow. After blowing,

the line shall be permitted to cool and contract, then the preceding blowing to be repeated.

The cleaning procedure should be repeated three times and unobstructed.

 199

Process and utility lines

a) Process, utility and auxiliary systems shall mainly be washed with water. Any line not

accessible to water, or lines which would trap water in such a way that it could not be

drained, may be blown out with air. Most of the process and auxiliary lines may be flushed

through established circuits from vessels filled with water for the purpose. Machinery

auxiliary lines should be flushed by oil.

To the maximum extent, the lines connected may be flushed with water contained within

vessels after hydrostatic testing. A single filling of a vessel may not provide sufficient

water to flush all lines for which it is the reservoir, in which case a continuous or

intermittent flow of water into the vessel should be maintained.

b) When washing exit lines of a vessel, it should be noted that, the vessel is adequately

vented to prevent a vacuum condition. Inadequate venting of vessels not designed for

vacuum service could rupture them.

c) In any system, to the maximum extent possible, flushing should be made downward, or

horizontally, and out at low points. The low point discharge opening may be temporary

openings made by disconnecting flanges or fittings. Normal drains may be used for

flushing outlets, provided they are equal to line size or nearly so. For best results, there

should be no restriction of the outlet or at any other point in a line undergoing cleaning.
 200

d) Too many circuits or openings shall not be flushed simultaneously.

e) Some lines, such as buried pump suction lines, must be flushed through a temporary

spool-piece and linesized valve flanged to one-end, and pointed to a safe location (not to

the pump suction). Compressed air is introduced to the other end and pressure allowed to

build. When the valve is suddenly opened, the sudden release of pressure will effectively

clean the line. Flushing shall be done through all vents, drains and other side connections,

by-passes and their main channels alternatively.

f) Flushing line debris into equipment where it may become trapped or lodged shall be

avoided.

g) All control valves should be blocked off and bypassed until the major part of the foreign

matter has been removed from their systems. Then remove the bottom plate of the control

valve or, if the valve is closed, remove the valve itself from the line, and flush through the

opening thus created. Finally, replace the plate or valve and flush through the valve in

normal alignment (if the valve is opened or can be opened).

h) Flow meter and restriction orifices should not be installed until lines are clean. Any

orifices installed before cleaning should be removed.

i) At the conclusion of flushing any system, it shall carefully be checked to see that normal

alignments are restored, temporary connections are broken, and temporary breaks

reconnected, check valve flappers and/or coverplates replaced, and orifices installed, etc. In
 201

the case of lines which will receive further cleaning during subsequent pump break-in, this

instruction may be qualified in part.

When flushing of process lines is finished, drain water from the system as completely as

possible. Provide ample top venting during the draining operation, or whenever the level is

being lowered in a vessel, to avoid pulling a vacuum on the equipment. Blow lines with air

to effect further water removal.

The basic utility systems such as steam, water and air should be put in normal working

order after they have been cleaned so that supplies will be available for further operations.

10.3.1.5 Instruments

In general the instruments should be checked against the design data as well as to be

checked for installation, calibration and operation as per the following list:

a) Installation check

i) The instrument is properly installed and accessible for operation and

maintenance. ii) All wiring is checked out.

iii) All loop checks is completed.

b) Calibration check

i) The instrument is calibrated for operation.

ii) Orifice plates are installed after hydrotest and line flushing.

iii) The proper charts are installed on all recorders.

c) Operation check

i) Power is supplied to all instruments.

ii) All alarms are test actuated and interlock systems checked.
 202

iii) Instruments, connecting piping, and pneumatic tubing are checked for leaks.

10.3.1.6 Acid cleaning of compressor lines

Mill scale, dirt, heavy greases, and other foreign materials that could enter the compressor

and result in operating and maintenance problems must be removed from the compressor

system as required in the Piping & Instrumentation Diagrams (P & IDs). The following

items must be acid cleaned:

a) All make-up gas piping including spill-back lines.

b) Make-up compressor suction lines and drums. Suction drums may be acid

cleaned where practical.

c) Make-up gas coolers and intercoolers.

d) Fuel gas lines to gas turbine burners.

10.3.1.7 General notes for dry-out and boil-out

1) The heater refractory dry-out, plant dry-out and chemical boil-out procedures can be

combined in the interests of saving time. It is likely, however, that the heat input during

either the heater refractory or the Unit dry-out procedures may be excessive for controlled

chemical boil-out. Therefore, combining the two or three operations may require a

temporary interruption of the drying-out procedure while the flushing operation is

completed and the steam generation facilities made completely operational.

 203

2) The drying-out and boil-out periods present an opportune time to check out the operation

of auxiliary equipment and instrumentation. The circulating pumps should be operated in

rotation to make certain that there will be no difficulties during final start-up.

10.3.1.8 Catalyst loading

Initial catalyst loading activities shall be performed according to the Licenser’s and/or

catalyst manufacturer’s procedures under supervision of the Licenser’s representatives. Full

attendance and cooperation of the Licenser’s responsible authorities is required.

10.3.1.9 Tightness test

During equipment cleaning, lines have been disconnected, orifice plates and blinds

removed and re-installed. As a consequence, tightness tests shall be required to eliminate

leakages due to gaskets which have been damaged, flanges or drains which have been left

open. Tightness test is to be carried out after final installation by air, steam, nitrogen or the

proper process fluids.

All joints, flanges, packing glands, etc. must be checked for leaks by means of a sensitive

detector, for example by using a soapy solution. Thermal insulation of flanges shall be

done only after the final pressure test of the section is completed.

Air or nitrogen are commonly used for tightness test purpose. Tightness test pressure will

depend on the operating pressure of the system under test. Normally shall be 1.2 times the

normal operating pressure provided that this does not exceed the set of the PSV existing in
 204

the section. And, anyhow, the maximum test pressure is normally limited by the available

plant or Instrument Air pressure. When operating pressure is considerably higher that of

said air, a preliminary tightness test is done with air and final tightness test is done with

process fluid during start-up.

The acceptability of the test is given by the pressure drop that can occur in a limited period

of time. It is normally accepted that the tightness of a section is reasonably good when said

pressure drop is less than 1% in two hours time.

10.3.2 Normal start-up procedures

Placing the new Unit in operation can be made through several methods depending on the

experiences of operational crew. It is common practice to buy in product and start up the

last past of the process first and work backwards to the front. Raw materials are fed into the

plant – usually at reduced rate until reaction conditions have been established. As each

section is started up, establish as quickly as possible that process conditions are as

expected; Plant is brought slowly to design feed-rates and operating conditions.

If potentially serious problems develop, there should be no hesitation on going into an

emergency shutdown.

The normal start-up activities can proceed when the following main commissioning and

precommissioning steps are completed:

- Heater refractory dry-out.

- Line and equipment flushing.

 205

- Rotating equipment run-in.

- All other activities outlined in Section 10.3.1 above.

Appendix D gives the general index for key components of a commissioning system file

for the 2- EH plant.

10.3.2.1 Prestart-up check list

The procedure describes in general terms, the steps to be followed for placing the Unit on

stream. The exact sequence of events depends on the flow scheme of the particular Unit;

however, the following steps must be completed before charging feed to the Unit.

- All unnecessary blinds are removed.

- All relief valves are tested and installed.

- All temporary lines have been removed.

- The flare header is purged and in service.

- The sewers are in service.

- The heaters are steamed out.

- The fuel oil and fuel gas lines are in service.

- The pilots are lit in all heaters.

- The orifices are installed and are correct in direction of flow.

- All instruments are ready for service.

- All utilities are in service.

- All drains and vents are closed.

- Control valves and bypasses are blocked in.

- All compressors are blocked in.

 206

- The chemical systems are ready for operation.

- The catalysts have been filled or regenerated.

- The unnecessary connections such as pump out, etc. are closed.

- All fire fighting facilities are ready for operation.

10.3.2.2 Make area safe

Remove all welding gear from area and all maintenance tools not of a non-sparking nature,

clear away all planks and scaffolding. No further work to be done except with work permits

and, if necessary, specific welding permits. "No Smoking" signs must be re-installed, if

required. (More information is contained under safety practices)

10.3.2.3 Utilities commissioning

All utilities such as various types of steam, condensate, boiler feed water, fuels and plant

air, instrument air, nitrogen, and plant water shall be commissioned. Do not put cooling

water into exchangers, which are to be left with water side drains and vents open and

drained until after steam-out.

10.3.2.4. Establish flow in the unit

The Unit should be lined up and final check shall be carried out to introduce the feed to the

Unit. All safety precautions should be taken into account. The feed to be charged at turn

down ratio of the Unit design throughput according to the stepwise start up procedure

developed. Hydrocarbons circulation in the coils of reboiler heaters shall be maintained at

 207

all times at a flow rate close to the design values in order to avoid coke deposition inside

the coils.

10.3.2.5 Adjust operation to obtain quality

On the basis of laboratory tests, operating conditions must be adjusted to meet

specifications on the products as well as product yields.

10.4 Performance Trails

Once the plant is fully operational, the final proving trail or performance run is performed

in order to prove the plant can do what it is supposed to do;

 The values or range of values for each independent variable - flow, temperature,

pressure, level, concentrations, etc. to which the plant must be operated to are

determined;

 Control of plant operating conditions has been achieved i.e. temperature, pressures,

levels and analyses are reasonably constant or in the case of a batch process, there is

repeatability;

 Daily material and energy balanced can be performed and that these agree with

official production figures;

 Product specifications are being achieved consistently.

 The plant is brought up to those conditions.

There is need to verify the physical operation, capability and capacity of plant and

equipment;
 208

Energy and mass balance; Process chemistry; Efficiencies, yields and quality; are all to

specification.

It is common practice to prove performance repeatability and plant integrity as part of the

performance test. This is usually carried out by

 Shutdown and Start Up the plants on several occasions and bring it up to test

conditions to prove repeatability. Also ramp down and ramp up while online;

 Re-inspection of critical process equipment - particularly columns to ensure they

have not been damaged by the performance run.

10.5 Safety Practices

Generation and implementation of effective emergency response and spill control

procedures are fundamental aspects of a safety management system. The on-site emergency

plan, prepared for Regulation 9 of COMAH should address procedures for dealing with

emergency situations involving loss of containment in general terms. Guidelines to safety

practices include;

 Containing and controlling incidents so as to minimise the effects and to limit

danger to

persons, the environment and property;

 Implementing the measures necessary to protect persons and the environment;

 209

 Description of the actions which should be taken to control the conditions at events

and to limit their consequences, including a description of the safety equipment and

resources available;

 Evacuation of areas in the event of fire or toxic gas emission should be addressed in

an emergency evacuation procedure. This should specify designated safe areas,

assembly points and toxic gas shelters.

 Arrangements for training staff in the duties they will be expected to perform;

 Arrangements for informing local authorities and emergency services; and

 Arrangements for providing assistance with off-site mitigatory action.

The emergency plan should be simple and straightforward, flexible and achieve necessary

compliance with legislative requirements. Furthermore separate on-site and off-site

emergency plans should be prepared.

10.6 Shut Down and Emergency Procedures

The possible types of shutdown envisaged in the plant unit are:

 Scheduled shutdown.

 Maintenance shutdown.

 Emergency shutdown.

 Reactor trips.

 Shutdown to a standby condition.

 210

The Standard Operating Procedures for each type of reactor must be adhered to when

shutting a reactor down. Appendix E discusses the likely problems that can arise from the

process plant, causes, and curtailing steps to be taken.

10.6.1 Scheduled shutdown

A scheduled shutdown is initiated by the Operational Technician during normal operation

of the reactor when maintenance is required or feed supply is low or exhausted. The

shutdown procedure will depend on the type of reactor and the process chemistry.

Some steps taken in a reactor shutdown may include:

 Shutting off one or more of the reactant feeds to stop reactions and heat generation

particularly if reactions are exothermic.

 Shutting off heating or cooling to the reactor or feed preheat system.

 Cooling and flushing products from the reactor by recirculating one of the feeds -

no reactions can take place when the other reactant flow is stopped.

 When the reactor has been flushed and cooled:

 All feed/product flows are stopped.

 Agitators are stopped.

 211

10.6.2 Maintenance shutdown

When maintenance is required to the reactor equipment, it is possible that the equipment

may need to be entered so work can take place.

The shutdown should be a scheduled or planned shutdown as per Standard Operating

Procedures where equipment is isolated (process, mechanical and electrical), cooled and

depressurized, purged and gas freed, cleaned, gas tested on a continuous basis prior and

during entry.

A planned reactor shutdown will prevent plugging of lines or plugged reactor, possible

damage to equipment, possible injury. To prepare the reactor for shutdown, the reactor can

be:

 Thoroughly drained and pumped out to remove chemical liquids.

 Purged with steam or inert gas to remove vapours.

 Solvent washed to remove deposits that build up on reactor internal surfaces.

 Flooded with water or a solvent to remove any remaining chemicals

 Any chemicals trapped in the reactor must be flushed out.

 Isolated to prevent the entry of hazardous chemicals.

 Drained and steam cleaned to remove remaining deposits.

During decontamination, regular sampling of the atmosphere inside the reactor is required

to ensure toxic or explosive atmospheres do not build up inside the reactor that could be a

hazard to equipment or personnel.

 212

Gas testing must be carried out before anyone enters the vessel to ensure the atmosphere is

not toxic, explosive or oxygen deficient.

10.6.3 Emergency shutdown

An emergency shutdown is initiated in the event of a fire, major spill, instrument failure,

power failure or the reaction taking place is running away.

Emergency shutdown procedures must be followed during a shutdown sequence.

10.6.4 Reactor trips

Shutdown of a reactor unit can be initiated by the automatic shutdown system due to

abnormal temperature, levels, pressures or flows that can be above or below trip points.

Typical shutdowns initiated by trips may include:

 Low liquid level in the reactor.

 High viscosity causing increased load on the agitator.

 Agitator or mixer failure.

 High pressure and high temperature.

 Low feed flows.

10.6.5 Shutting down to a standby condition

When a reactor is to be shutdown for a short period of time for maintenance on auxiliary

equipment, the reactor is shutdown to a standby condition.

A standby shutdown allows a quick start-up of the reaction unit after maintenance is

completed to minimise lost production time and off-spec material.

Standard Operating Procedures must be referred to, to shutdown each type of reactor to a

standby condition.
 213

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Awolowo University, Ile- ife.

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New York.

 Bhattacharya, B.C. (2008). Introduction to Chemical Equipment Design:

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Wiley and Sons, New York

 Chemfate. 2003. Environmental Fate Database. Syracuse Research Corporation.

Available at http://esc.syrres.com/efdb/Chemfate.htm (accessed November

12, 2012).

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John Wiley and Sons Inc. pp 207- 230

 214

 Encyclopedia of Chemical Processing and Design by John J Mc Ketta

 Encyclopedia of Chemical Technologies by Kirk-Othmer. (Vol 1) page 749-756

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Health and Environmental Data for Common Hazardous Substances,

McGraw Hill, New York, NY.

 Hancock, E. G. (ed.) (1973) Propylene and Its Industrial Derivatives (New York:

John Wiley & Sons) Chapter 9, pp. 333–367.

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 Hazardous Substances Data Bank (HSDB). 2004. Hazardous Substances Data

Bank. Toxicology and Environmental Health Information Program,

National Library of Medicine, Bethesda, MD, available on-line at

http://toxnet.nlm.nih.gov/cgibin/sis/htmlgen?HSDB.
 215

 Lewis, R.J. 1997. Hazardous Chemicals Desk Reference, Fourth Edition, Wiley

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NIST Chemistry WebBook, http://webbook.nist.gov/ (accessed

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Obafemi Awolowo University, Ile- ife, Nigeria.

 Octave Levenspiel. (1999). Chemical Reaction Engineering, 3rd Ed. John Wiley &

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 Ojima, I.; Tsai, C.Y.; Tzamarioudaki, M.; Bonafoux, D. (2000).Organic

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 Organization for Economic Co-operation and Development (OECD). 1995. 2-

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at http://cs3-hq.oecd.org/scripts/hpv/

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 R.K. Sinnott. (2005). Chemical Engineering Design Volume 6 (4th Edition).

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Heinemann/Elsevier Publications. pp 260-287

 Smith J.M.; H.C. Van Ness, M.M. Abbot. 2001. Introduction to CHE

Thermodynamics, 6th Ed. McGraw- Hill (Asia), p. 637).

(http://www3.gov.ab.ca/env/info/infocentre/publist.cfm), November 2004

 Stanley, K.H. LSU (September 18, 2001). (Hydroformylation (Oxo) Catalysis)

http://chem-faculty.lsu.edu/stanley/webpub/4571-chapt16-

hydroformylation.pdf (accessed November 12, 2012)

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 Verschueren, K. 2001. Handbook of Environmental Data on Organic Chemicals,

Fourth Edition, Wiley Interscience, John Wiley & Sons, New York, NY.

 WHO. 1993. Toxicological Evaluation of Certain Food Additives and

Contaminants. WHO Food Additives Series No. 32. Prepared by: The

forty-first meeting of the Joint FAO/WHO Expert Committee on Food

Additives (JEFCA). WHO, Geneva. ISBN: 92- 4-166032-5, available at

<http://www.inchem.org/documents/jecfa/jecmono/v32je04.htm>

(accessed September 11, 2003).

 Wojtasinski, J. G. (July 1963) Measurement of Total Pressures for Determining

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Isobutyraldehyde-n-Butyraldehyde. J Chem Eng Data, pp. 381–385.

 218

APPENDICES
 219

APPENDIX A

MECHANICAL DRAWINGS FOR

DISTILLATION COLUMN (DC) 2

Dimensions: mm Bundle removal clearance: 6657

7535
2 0

721 5885 929

0
2 4

318

5462
(1)
(1)

1 180

4 0
(1)

3180

5546
318

392

779
1 SS1 3 CG SS2
(2)

(1)

90 90
1056

1056
705

705
3 180
3
153 15

Nozzles Couplings / Supports Design Specifications Shell Tube Filename; OGUNGBENRO Adetola Elijah
(1) (2)
(CHE/2007/083)
Label Size: Description Project. Label Size: Description Project. Design Pressure bar 1.11 1.11 Aspen Teams verification file
1 219.1 150 # ANSI W.N.RF 360153.5 SS1 2 133.0 Bolt Holes 360151 Test Pressure bar 1.0 1.0 Service of Unit:
2 219.1 150 # ANSI W.N.RF 360153.5 SS2 2 133.0 x 266.0 Slots 360151 Design Temperature °C 82.28 82.8 Item No.:
Date: 23/10/2012 Rev No.:
3 355.6 150 # ANSI W.N.RF 360153.5 Number of Passes 1 2
4 355.6 150 # ANSI W.N.RF 360153.5 Corrosion Allowance mm 20 4 Aspen Technology, Inc.
Radiographing Spot Spot
Midlothian, Virginia
Wt min: 148375 max: 152609.6086 Bundle: 5268 kg

Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001

Setting Plan
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 – 01

A-1
 Component O.D. Thk. Materials of Construction Dimensions: mm

Nozzle 1 Inlet 219.1 12.7 150 # ANSI W.N.RF Flg SA-105 on SA-106 Gr B Sml Pipe
Nozzle 2 Outlet 219.1 12.7 150 # ANSI W.N.RF Flg SA-105 on SA-106 Gr B Sml Pipe
Nozzle 3 Outlet 355.6 11.1 150 # ANSI W.N.RF Flg SA-105 on SA-106 Gr B Sml Pipe
Nozzle 4 Inlet 355.6 11.1 150 # ANSI W.N.RF Flg SA-105 on SA-106 Gr B Sml Pipe

Shell Cylinder 1219 15.0 SA-516 Gr 70 Steel Plt

Fr Hd Cylinder 1219 13.0 SA-516 Gr 70 Steel Plt
Fr Hd Cover 1325 56.0 SA-516 Gr 70 Steel Plt (Flat Cover)
Re Hd Cover 1178 13.0 SA-516 Gr 70 Steel Plt (Ellipsoidal Cover)
Shell Cover 1307 13.0 SA-516 Gr 70 Steel Plt (Ellipsoidal Cover)
Front TubSh 1325 32.0 SA-516 Gr 70 Steel Plt
Rear TubSh 1179 32.0 SA-516 Gr 70 Steel Plt
Fr Hd Flng TubSh 1325 61.0 SA-105 Carbon Steel Forg (Hub Flange)
Re Hd Flng TubSh 1268 63.0 SA-105 Carbon Steel Forg (Ring Flange)
Fr Hd Flng Cover 1325 61.0 SA-105 Carbon Steel Forg (Hub Flange)
Fr Shell Flng 1325 37.0 SA-105 Stainless Steel Forg (Hub Flange)
Rear Shell Flng 1413 31.0 SA-105 Stainless Steel Forg (Hub Flange)
Shell Cover Flange 1413 36.0 SA-105 Stainless Steel Forg (Hub Flange)
Design Specifications
Back Flng Re TubSh 1268 102.0 SA-516 Gr 70 Steel Plt (Ring Flange) Shell Side
Tube Side
Fr Hd Gskt TubSh 1251 3.2 Flt Metal Jkt Asbestos Soft Steel (Periph. Width 13.0 mm) Design Pressure bar 1.11 1.11
Re Hd Gskt TubSh 1179 3.2 Flt Metal Jkt Asbestos Soft Steel (Periph. Width 10.0 mm) Test Pressure bar 1.0 wwwwwwww
1.0
wwwwwwww
Fr Hd Gskt Cover 1251 3.2 Flt Metal Jkt Asbestos Soft Steel (Periph. Width 13.0 mm) Design Temperature C 82.8 82.8
wwwwwwww
Front Shell Gasket 1251 3.2 Flt Metal Jkt Asbestos Soft Steel (Periph. Width 13.0 mm) Number of Passes 1 2
wwwwwwww
Shell Cover Gasket 1339 3.2 Flt Metal Jkt Asbestos Soft Steel (Periph. Width 13.0 mm) Corrosion Allowance mm 20 4
wwwwwwww
Fr Hd Blts TubSh 19 SA-193 B7 Steel Blt (60 Bolts on 1283.0 mm B.C.) Radiographing Spot wwwwwwww
Spot
Re Hd Blts TubSh 16 SA-193 B7 Steel Blt (44 Bolts on 1229.0 mm B.C.) TEMA Type: AES Size: 1189-6096 wwwwwwww
Area:
wwwwwwww
Fr Hd Blts Cover 19 SA-193 B7 Steel Blt (60 Bolts on 1283.0 mm B.C.) Tube Type: Plain # Holes: 2078 Length: 4877 mm wwwwwwww
Shell Cover Bolting 19 SA-193 B7 Steel Blt (44 Bolts on 1371.0 mm B.C.) Layout: 31.75 mm (30) Tube-Ts Joint: Strength Wld wwwwwwww
Tubes 19.10 21.4 SA-249 TP304 Wld Hi Alloy Tube (Plain Tubes) Baffle Type: Single Seg. Cut: 30% H No: 8 wwwwwwww
Baffles 1183 13.0 SA-285 Gr C Steel Plt Baffle Spacing (C-C): 610 Inlet: 879 mm wwwwwwww
wwwwwwww
Shell Supports 13.0 SA-285 Gr C Steel Plt Impingement Protection: None
wwwwwwww
Shell Cover Cylinder 1307 13.0 SA-516 Gr 70 Steel Plt Code: ASME VIII-1 2001 TEMA Class: P wwwwwwww
Wt min: 148375 max: 152609.6086 Bundle: 5268 kg www1
Drawn By: OGUNGBENRO Adetola Elijah Ckd By:
Apvd By:
Dwg No.: 3 Rev: Date: 23/10/2012
Filename; OGUNGBENRO Adetola Elijah
(CHE/2007/083)
Aspen Teams verification file
Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia

Bill Of Material
Dwg No.: Rev:
3200 - 03

A-2
 OD 1190
OD 1251

OD 1251 ID 1225 3.2

OD 1254

OD 1325

12.7 ID 1193 13

OD 1325

OD 1254

OD 1251 ID 1225 3.2

OD 1251

OD 1190

OD 1186

OD 1251

OD 1251 ID 1225 3.2

OD 1254

OD 1325

ID 1189 15

OD 1413

OD 1339

A-3
OD 1268

ID 1152
OD 1182

OD 1179

OD 1149

OD 1179 ID 1159 3.2

OD 1182

ID 1152

OD 1268

OD 1339 ID 1313 3.2

OD 1342

OD 1413

ID 1281 13
Dimensions: mm TEMA Type: E
Top View

Front Rear

355.6 355.6

574.2 412.9
752.0 590.7
57.1 104.3

872.7 596.6 596.6 872.7

1482.3 1206.2 1482.3

32.0 879.2 609.6 13.0 609.6 879.2 32.0

Side View

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
Aspen Teams verification file
Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale:1:1428
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Bundle Detail
Baffles TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 – 05

A-4
 Shell ID 2300 mm
Row Holes H G O.T.L. 1139.3 mm
Baffle cut to C/L 242.2 mm
40 14
39 28
38 32
37 40
36 42
35 48
34 40
33 56
32 48
31 60
30 62 F E
29 64
28 66
27 68
26 66 552
25 68
24 60
23 68
22 60
21 72 44.4
20 72 552
19 60
18 68 22.2
17 60
16 68
15 66 15.9
14 68
13 66
12 64 D C
11 60
10 50
9 48
8 56
7 34 27.5
6 40
5 36
4 34
3 28
2 24
1 14 25.8
B A
2078

Design Specifications Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
Number of Tube Holes 2078 Tie Rod Locations- NIL Aspen Teams verification file
Tube Outside Diameter 19.1 mm Service of Unit:
Tube Pitch 25.4 mm Item No.:
Date: 23/10/2012 Rev No.:
Tube Pattern Triangular
Tube Passes 2 Aspen Technology, Inc.
Tube Thickness 21.4mm
Midlothian, Virginia
Scale:
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Tube Layout
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 – 06

A-5
 0

550

934
0

13
1307 O.D.
6
270 90
1

7
23

62
180
Front End View Side View
Filename; OGUNGBENRO Adetola Elijah
Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Weld joint details per drawing 20 Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 45
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Shell Cover Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 08
32
78

A-6
 0

414
1268 OD
270 90
51

18

63
180
Front End View Side View
Filename; OGUNGBENRO Adetola Elijah
Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Weld joint details per drawing 20 Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 30
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Rear Head Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 10

A-7
 6090

32 879 7 x 610 = 4267 614 265 32

Plan
View

Elevation
View

11 12

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Weld joint details per drawing 20 Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 35
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Bundle Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 11

A-8
 0

318
215

270 90

215

318

180

39 C
1 Supports 1239 O.D. 13 Tk

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Weld joint details per drawing 20 Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 18
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Support Plate De
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 12

A-9
 60 22 Dia Bolt Holes
0
1283 Bolt Circle

13
1186 Dia

1251 Dia

1325 OD
90 270

10 Chamfer

180
56 Thk. 5
Front Head Cover Rear End View
51 5 Filename; OGUNGBENRO Adetola Elijah
Notes:
45 6 (CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
125 Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 16.9
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Flat Cover Detai
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 – 13

A-10
 60 22 Dia Bolt Holes
0

1283 Bolt Circle

13

1251 Dia

1190 Dia

1186 Dia

1251 Dia
1325 OD
270 90

10 Chamfer

180
32 Thk. Front End View 13 Front TubSh
5 22 5 Filename; OGUNGBENRO Adetola Elijah
Notes:
6 10 6 (CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
125 125 Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 16.9
25.65 Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Tubesheet Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 – 14

A-11
 0

1149 Dia

1179 OD
90 270

180
14 Rear TubSh Rear End View
Filename; OGUNGBENRO Adetola Elijah
Notes:
32 Thk. (CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
27 5 Bolt holes to straddle centerlines Service of Unit:
Item No.:
125 Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 11.5
25.65 Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Tubesheet Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 32000 - 15

A-12
10

10
1251 O.D.

1251 O.D.
1225 I.D.

1225 I.D.
6 Radius 6 Radius

33 31
Front Head Gaskets at Covers Front Head Gaskets at Tbshts

3.175 Thk. 3.175 Thk.

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 19.8
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Gasket Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 – 16A

A-13
 1179 O.D.
1159 I.D.

32
Rear Head Gaskets at Tbshts

3.175 Thk.

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 19.8
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Gasket Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 – 16B

A-14
 1251 O.D.

1339 O.D.
1225 I.D.

1313 I.D.
35 36
Front Shell Gasket Shell Cover Gasket

3.175 Thk. 3.175 Thk.

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 19.8
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Gasket Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 16C

A-15
 87

56 26
5

1325 OD
60 22 Dia Bolt Holes

Radius
1283 Bolt Circle
30

5
Dia
1254
125

1219 OD
2
1193 ID

Dia
1226
19 Fr Hd Flng Cover

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 11
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Flange Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 18

A-16
 87 63

26 56 32 26
5 5
1325 OD

1325 OD
60 22 Dia Bolt Holes
Radius

Radius
1283 Bolt Circle
30 30
5

5
Dia

Dia
1254

1254
125
1219 OD

1219 OD
125
2

2
1193 ID
Dia

1189 ID
1226 Dia
1226

17 Fr Hd Flng TubSh 21 Fr Shell Flng

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 11
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Flange Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 19

A-17
 57 62

26 25 31 26
6 5

1413 OD

1413 OD
44 22 Dia Bolt Holes

Radius
30

1371 Bolt Circle

5
Dia
Dia

1342
125

1339

1307 OD
Radius

2
1281 ID
1314 Dia
30
5

125
1219 OD

12121689 DIiD
a

22 Rear Shell Flng 23 Shell Cover Flng

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 15
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Flange Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 20

A-18
1268 OD

1268 OD

1229 Bolt Circle

Dia

Dia

1179 ID
1182

1182
1152 ID

Filename; OGUNGBENRO Adetola Elijah

Notes:
(CHE/2007/083)
All Dimensions In Millimeters Aspen Teams verification file
Bolt holes to straddle centerlines Service of Unit:
Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1: 13
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Flange Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 21

A-19
WELD WELD WELD WELD
JOINT JOINT JOINT JOINT

60

45
11 18 60 16 45 61
21 28 26 71
21 36 81

60
45

12 45
18 17 45 61
22
28 27 71
22
37 81

51

Filename: OGUNGBENRO Adetola Elijah

Notes:
Aspen Teams verification file
All Dimensions In Millimeters Service of Unit:
Welding in accordance with Code Item No.:
Date: 23/10/2012 Rev No.:

Aspen Technology, Inc.

Midlothian, Virginia
Scale: 1:76
Rev: Date: Description Dwg Ckd Appd ASME VIII-1 2001
Weld Joint Detail
TEMA Type: AES
Size: 1189-6096 Dwg No.: Rev:
TEMA Class: P 3200 - 24

A-20
 240

APPENDIX B

MATERIAL SAFETY DATA SHEET

(MSDS) FOR 2- ETHYLHEXANOL

MATERIAL SAFETY DATA SHEET

MSDS No. 02-11

According to Regulation (EC) No.1907/2006, REACH

2-ETHYL-1-HEXANOL (OCTANOL)
Revision: 7 Last up date: October 14, 2008 Date issued: July 21,1999 Page 1/7

1. IDENTIFICATION OF THE SUBSTANCE/PREPARATION AND OF THE

COMPANY/UNDERTAKING

1.1. Identification of the substance/preparation

Trade Name 2-Ethyl-1-hexanol (Octanol)

Chemical Name 2-Ethylhexan-1-ol
Chemical Family Alcohols
Chemical Formula CH3 (CH2)3 CH(C2H5) CH2OH
Molecular Weight 130.3

1.2.Uses of the substance/preparation

Production of PVC-plasticizers, plastics and synthetic rubber, synthetic lubricants (in form of
dicarbonic acid esters); oil, fat, wax and resin solvent.

1.3. Company/undertaking identification

Company Name OLTCHIM SA

Adress 1,Uzinei Street, 240050-R@mnicu V@lcea, Romania
Phone +40 / 250 / 701200
Fax +40 / 250 / 735446
e-mail oltchim@oltchim.ro

1.4.Emergency telephone number +40 /250/738141

2. HAZARD IDENTIFICATION

Health effects: It is harmful if is swallowed, inhaled, or absorbed through skin.Vapors and mists
severely irritate the eyes and respiratory tract especially when heated. May affect central nervous
system, have a narcotic effect. May cause allergic skin reaction.

Environmental effects: No critical hazard to the environment in the ordinary sense of valid
regulations. This product is readily biodegradable. No ecological problems are to be expected
when the product is handled and used with due care and attention. 2-Ethylhexanol is not classified
as dangerous for environmental according to Directive 67/548/EEC, Annex I.

Emergency overview: 2-Ethylhexanol is a combustible and flammable liquid. In contact with

strong oxidizers may cause fire. Vapor/air mixtures are explosive above 750C. The substance is
very little soluble in water, floats on the water level.

Elaborated by: Technical &Development Department

B-1
2-ETHYL-1-HEXANOL (OCTANOL)
MSDS No.02-11
Revision: 7 Last up date: October 14, 2008 Date issued: July 21, 1999 Page 2/7
3. COMPOSITION/INFORMATION ON INGREDIENTS

Hazardous Concentration CAS No. EC No. Annex I Hazard Risk

components %,wt. Index No. Symbol phrases
/constituents
2-Ethylhexanol 99, 5 104-76-7 203-234-3 - - -

4 . FIRST - AID MEASURES

Seek medical attention immediately in all cases of exposure!

Inhalation: Inhalation of vapors or mist is irritating to the upper respiratory tract. May have
narcotic effect. Difficult breathing, coughing, headache, dizziness and drowsiness may occur.
Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult give
oxygen. Call a physician.

Skin contact: Causes skin irritation. May be absorbed through skin. May cause sensitization or
allergic skin reaction in some individuals. Prolonged skin contact may result in dermatitis.
Wash the contaminated skin with plenty of soap or mild detergent and water for at least 15 minutes
while removing contaminated clothing and shoes. If irritation persists after washing, get medical
attention.

Eye contact: Causes irritation, redness and pain.

Wash the eyes immediately with large amount of water lifting the upper and lower lids, until no
evidence of chemical remains at least 15-20 minutes. If irritation persists after washing get medical
attention. Contact lenses should not worn with this product.

Ingestion: May have narcotic effect. May cause abdominal pain, nausea, headache, dizziness and
diarrhea. Large doses may affect kidneys and liver. Give large amount of water to drink. If large
amounts were swallowed, get medical advise. Never give anything by mouth to mouth to an
unconscious person.

5. FIRE - FIGHTING MEASURES

Suitable extinguishing media: Dry chemical, foam or carbon dioxide and water spray.

Unsuitable extinguishing media: Do not use a solid stream of water (water jet), since the stream
will scatter and spread the fire. Use water spray to isolate the hazard area and to keep fire-exposed
tanks cool.

Exposure hazards: 2-Ethylhexanol is a combustible and flammable liquid. In contact with strong
oxidizers may cause fire. Vapor/air mixtures are explosive above 750C. Vapor may flow along
surface to distant ignition sources and flash back. Carbon monoxide and dioxide may form when
heated to decomposition. In case of large fire and remove the containers if this it is possible.

B-2
2-ETHYL-1-HEXANOL (OCTANOL)
MSDS No.02-11
Revision: 7 Last up date: October 14, 2008 Date issued: July 21, 1999 Page 3/7
Protection of fire-fighters: Wear full protective clothing and self contained breathing apparatus
with full face piece operated in positive pressure mode.

6. ACCIDENTAL RELEASE MEASURES

Personal precautions: Remove all sources of ignition. Ventilate area of leak or spill. Persons
performing clean-up work should wear adequate personal protective equipment and a self-contained
breathing apparatus with full facepiece operated in the pressure demand or other positive pressure
mode. Keep unnecessary and unprotected personnel away from hazard area.

Environmental precautions: Prevent from contamination the ground and the surface water by
isolating the hazard area. Contain and recover liquid when possible. Keep closed containers and
dispose according to all applicable federal, state or local environment regulations

Methods of cleaning up: Absorb spills with dry sand, earth or similar non-combustible absorbent
material then collect into drums for later disposal. For large spills, dike and pump into suitable
containers for disposal. Use water spray to reduce vapors and flush area with water. Resulted
waste water will be treated in biological treatment plant. Dispose of under valid legal waste
regulations.

Special precautions: Do not use combustible materials, such as saw dust to absorb the spills.. Do
not flush to sewer! Use only non sparkling tools and equipment.

7. HANDLING AND STORAGE

Handling: Protect containers from physical damage. Use non sparkling tools, electric equipment
and venting system. Sources of ignition such as smoking and open flames are prohibited when
2-ethylhexanol is handled. Do not use compressed air or oxygen for filling, discharging or
handling. The personel which handling the product must wear protective equipment.

Storage: Store in a tightly closed containers in a cool, dry, well ventilated area away from sources
of heat and incompatible substances. Drums must be equipped with self-closing valves, nitrogen
blanket. Containers of this material may be hazardous when empty since they retain product
residues (vapors, liquid).

8 . EXPOSURE CONTROLS / PERSONAL PROTECTION

Exposure limits Not established

Engineering control : A system of local and/or general exhaust is recommended to keep employee
exposure as low as possible. Local exhaust ventilation is generally preferred because it can control
the emissions of the contaminant at its sources, preventing dispersions of it into the general work
area. Ventilation equipment should be explosion- proof if explosive concentration of dust, vapor or
fume are present.

B-3
2-ETHYL-1-HEXANOL (OCTANOL)
MSDS No.02-11
Revision: 7 Last up date: October 14, 2008 Date issued: July 21, 1999 Page 4/7
Respiratory protection: For conditions of use where exposure to substance is apparent , consult an
industrial hygenist. For emergencies or instances where the exposure level are not known, use a
full face piece positive pressure air-supplied respirator.

Hand protection : Wear rubber ( nitrile) gloves.

Eye / Face protection : Use chemical safety goggles and/or a full face shield when is possible

Skin protection : Wear impervious protective clothing, including boots, gloves, lab coat apron or
coveralls as appropriate, to prevent skin contact.

Other precautions: Maintain shower, eye wash fountain and quick-drench facilities in work area.

9. PHYSICAL AND CHEMICAL PROPERTIES

General informations
Appearance Clear liquid
Odor Characteristic

Important health, safety and environmental informations

pH value at 1g/l water 7

Boiling point 183-186o C
Flash point 75OC
Flammability flammable
Explosive properties explosive under open flame
explosive limits in air: 1,1-7,7% vol
Oxidizing properties no oxidizing properties
Vapor pressure at 20 oC 0,36 mmHg
Specific gravity (water=1) at 20o C 0,833
Solubility –water 1,1g/l
-organic solvents miscible with most common solvents
Partition coefficient (log Kow) 3,1
Dynamic viscosity at 20o C 10 mPas
Vapor relative density (air=1) 4,5
Evaporation rate (BuAc=1) 0.01
Viscosity, dinamic 8,8 mPa*s

Other informations
Melting point -76o C
Autoignition temperature 270 OC

10 . STABILITY AND REACTIVITY

B-4
2-ETHYL-1-HEXANOL (OCTANOL)
MSDS No.02-11
Revision: 7 Last up date: October 14, 2008 Date issued: July 21, 1999 Page 5/7

Chemical stability: Stable under ordinary conditions of use and storage.

Conditions to avoid: Heat, flame, sources of ignition and incompatibles.

Materials to avoid: Strong oxidizers and acids.

Hazardous decomposition products: Carbon monoxide and dioxide may form when heated to
decomposition. May produce acrid smoke and irritating fumes when heated to decomposition.

11. TOXICOLOGICAL INFORMATION

Animal toxicity data:

LD50/Oral, rat >3730 mg/kg
LC50/Dermal, rat >3000 mg/kg
LC50 /inhalation - rat > 20 mg/l/4h

Acute toxicity
Inhalation: Inhalation of vapor or mist is irritating to the upper respiratory tract. May have narcotic
effect. Difficult breathing, coughing, headache, dizziness and drowsiness may occur. May be
absorbed into the bloodstream with symptoms similar to ingestion.

Skin contact: Causes skin irritation. May be absorbed through skin. May cause sensitization or
allergic skin reaction in some individuals. Prolonged skin contact may result in dermatitis.

Eye contact: Causes irritation, redness and pain.

Ingestion: May have narcotic effect. May cause abdominal pain, nausea, headache, dizziness and
diarrhea. Large doses may affect kidneys and liver.

Chronic effect: Persons with pre-existing skin disorders or eye problems or impaired liver, kidney
or respirator function may be more susceptible to the effects of the substance.

CMR effects (Carcinogenity, Mutagenicity, toxicity for Reproduction):

Carcinogenity: No carcinogenic effect.
Mutagenicity: No mutagenic effect.
Toxicity for Reproduction: Not affect reproductive parameters.

12. ECOLOGICAL INFORMATION

Ecotoxicity
Fish P. promelas LC50=29.7mg/l/96 hours
Onchorhynchus mykiss LC50 >7.5mg/l/96 hours
Daphnia Daphnia magna LC50=39mg/l/48 hours
Algae Desmodesmus subspicatus IC50=11.5mg/l/72 hours

B-5
2-ETHYL-1-HEXANOL (OCTANOL)
MSDS No.02-11
Revision: 7 Last up date: October 14, 2008 Date issued: July 21, 1999 Page 6/7
Bacteria Ps.putida EC50=540mg/l/18hours

Mobility: 2-Ethylhexanol may enter the environment from industrial discharges, municipal waste
treatment, plant discharges or spills. Due to the low vapor pressure, the chemical is extended in air
in limited amount. Volatilization is not a dominant transport process.
Because 2-ethylhexanol is slightly soluble in water, may be expected to sink rapidly soils as
consequence may be transported into groundwater by leaching through fissures rather than matrix
pores.

Persistence and degradability: When released into the air, this material may be readily degraded
by reaction with photochemically produced hydroxyl radicals with a half-life of 10 hours. When
released into the soil, watercourses and groundwater this chemical may be readily biodegraded
under aerobic conditions (95% after 5 days).

Bioaccumulative potential: With regard to bio concentration factor BCF=13, bioaccumulation in

organism is not expected.

Bioaccumulation in Aquatic Organisms: The concentration of 2-ethylhexanol found in fish tissue

is expected to be about the same as the average concentration of 2-ethylhexanol in the water.

Other adverse effects: The substance has a harmfull effect on aquatic organisms. No ecological
problems are to be expected when the product is handled and used with due care and attention.
Do not allow to enter waters, waste water or soil!

13. DISPOSAL CONSIDERATIONS

Waste treatment: What ever cannot be saved for recovery or recycling should be handled as non-
hazardous waste. Any disposal practice must be in compliance with all local, regional and national
regulations. Do not dump into any sewers, on the ground, or into any body of water.

Packaging treatment: The empty containers/tanks are treated with steam and rinsed with plenty of
water. The resulted effluent are treated in the same way as waste. The empty and clean containers
are to be reused in conformity with regulations.

14. TRANSPORT INFORMATION

2-Ethylhexanol has not specific regulations of transportation.

15. REGULATORY INFORMATION

2-ETHYL-1-HEXANOL is not classified and labeled as hazardous material according to Directive

67/548/EC.

EC-Number: 203-234-3

B-6
2-ETHYL-1-HEXANOL (OCTANOL)
MSDS No.02-11
Revision: 7 Last up date: October 14, 2008 Date issued: July 21, 1999 Page 7/7
Hazard symbol: Xi Irritant

R phrases: R 36/37/38 Irritanting to eyes, respiratory system and skin.

S phrases: S 23 Do not breathe vapour.

S 28 After contact with skin, wash immediately with plenty
of water and soap.
S 36/37/39 Wear suitable protective clothing, gloves and eyes/face
protective.

16. OTHER INFORMATION

Precautions to be taken in handling and storing: Keep well ventilated the areas where
2-ethylhexanol is stored and handled.

Work hygienic practices: Avoid direct contact of substance with skin/eyes. Avoid the exposure of
personnel with with liver, kidney or lung damages to the substance.

Interdictions: Do not drink or eat in working area.

Do not smoke in or near working area.
The use of open flame in working areas is prohibited.

Uses and Restrictions: Advice in this document relates only to product as originally supplied.
Other derivative chemicals will have different properties and hazard.
Chemical intermediate for organic synthesis.

Hazardous reaction: 2-Ethylhexanol is a combustible and flammable liquid. Vapours may travel
considerable far distances. Vapours are heavier than air, may cumulate along the ground and in
enclosed spaces. Do not empty into drains. When burning, it may emit pungent fumes and toxic
carbon monoxide.

MSDS Revisions: This Material Safety Data Sheet is made in accordance to European Regulations
and will replace the previous version 6 dated July 17, 2008.

Revised information:

Chapter 14: it was modified transport information.

This MSDS has been elaborated in accordance with Regulation (EC) No.1907/2006 REACH
The information contained here in is based on the present state of our knowledge. It characterizes the
product with regard to the appropriate safety precautions. It does not represent a guarantee of the
properties of the product.
This MSDS cannot cover all possible situations which the user may experience during handling and
processing. Each aspect of the user's operation should be examined to determine if, or where, additional
precautions may be necessary. All health and safety information contained within this MSDS should be
provided to the user's employees or customers.

B-7
 248

APPENDIX C

SIMULATION GRAPHS FOR

CONTROL SCHEME OF OXO

REACTOR
 Vessel temp, Tank Volume and Liq Vol % graphs at reaction start up
HFR-DL17 C-1
100.00

7.821 (m3)

80.00

60.00
HFR - Liquid Volume Percent (%)

33.43 (C)

40.00

29.72 (%)

20.00

0.00
40.00 41.00 42.00 43.00 44.00 45.00 46.00 47.00 48.00 49.00 50.00 51.00 52.00 53.00 54.00 55.00 56.00 57.00 58.00 59.00 60.00 61.00
Minutes

HFR - Vessel Temperature HFR - Tank Volume HFR - Liquid Volume Percent
 Vessel Temp, Pressure Liquid vol Flow at reactor start up time
HFR-DL19 C-2
100.0

80.00

60.00
HFR - Liquid Volume SP (m3)

33.43 (C)

40.00

334.41 (bar)

20.00

2.323 (m3)

0.0000 1.179e-013 (m3

39.00 40.00 41.00 42.00 43.00 44.00 45.00 46.00 47.00 48.00 49.00 50.00 51.00 52.00 53.00 54.00 55.00 56.00 57.00 58.00 59.00 60.00 61.00
Minutes

HFR - Vessel Temperature HFR - Liquid Volume Flow

HFR - Vessel Pressure HFR - Liquid Volume SP
 Vessel temp, Tank Volume and Liq Vol % graphs at reaction steady state
HFR-DL17 C-3
100.00

7.821 (m3)

80.00

60.00
HFR - Liquid Volume Percent (%)

33.43 (C)

40.00

21.01 (%)
20.00

0.00
38.00 40.00 42.00 44.00 46.00 48.00 50.00 52.00 54.00 56.00 58.00 60.00 62.00 64.00 66.00 68.00 70.00 72.00 74.00 76.00 78.00 80.00 82.00 84.00 86.00 88.00
Minutes

HFR - Vessel Temperature HFR - Tank Volume HFR - Liquid Volume Percent
 Vessel Temp, Pressure Liquid vol Flow at reactor steady state time
HFR-DL19 C-4
100.0

80.00

60.00
HFR - Liquid Volume SP (m3)

33.43 (C)

40.00

20.00

2.47 (m3)

0.0000 1.179e-013 (m3

47.00 48.00 49.00 50.00 51.00 52.00 53.00 54.00 55.00 56.00 57.00 58.00 59.00 60.00 61.00 62.00 63.00 64.00 65.00 66.00 67.00 68.00 69.00
Minutes

HFR - Vessel Temperature HFR - Liquid Volume Flow

HFR - Vessel Pressure HFR - Liquid Volume SP
 HFR Liquid Mass Flow and Volume Flow at start up time
HFR-DL15 C-5
-1000

-1200

-1.225e+006 (kg

-1400
HFR - Liquid Volume Flow (m3/h)

-1600

-1786 (m3/h)

-1800

-2000
84.00 86.00 88.00 90.00 92.00 94.00 96.00 98.00 100.0 102.0 104.0 106.0 108.0 110.0 112.0 114.0 116.0 118.0 120.0 122.0 124.0 126.0 128.0 130.0 132.0 134.0
Minutes

HFR - Liquid Mass Flow HFR - Liquid Volume Flow

 254

APPENDIX D

COMMISSIONING AND SYSTEM

FILE (Abridged)
 Commissioning System File

Project Design of 72 000 tons/year 2- Ethylhexanol Plant

Plant 2- ETHYL HEXANOL

Prepared by OGUNGBENRO ADETOLA ELIJAH Date: Nov/24/2012
CHE/2007/083
Checked By Date:

Validated By Date:

D-1
 Commissioning System File

System:

INDEX

1. System P&ID’s
2. Decontamination procedure & isolation register
3. System cleaning procedures
4. Hazard Study and actions
5. Equipment Check Sheets, off and on site checks
6. System Punch lists
7. Action upon Alarm Sheet
8. Handover Certificate Construction/Maintenance to Commissioning
9. Project documentation check sheet prior to introduction of safe chemicals
10. Safe Chemical Commissioning authorization and Pre-commissioning Procedures
11. Leak Test Checklist and Procedures
12. Instrument Check Sheet
13. Motor Check Sheet
14. Interlock Check procedures
15. Emergency Shut Down System check procedures
16. DCS sequence test procedures
17. Relief Stream Check Sheets
18. Critical Insulation Checks
19. Critical Gasket Installation Checks
20. Lubrication Check Sheet
21. PSSR, Plant Check-out prior to introduction of Hazardous Chemicals
22. Documentation Requirements for Ongoing Maintenance Group
23. Authority to Introduce Process Chemicals, check sheet & Certificate
24. Commissioning Procedures
25. Standard Operating Procedures
26. Commissioning to Plant Handover Certificate

D-2
 3. System cleaning checklist & procedures

During the construction integrity test commissioning must follow with a cleaning
procedure for the pipe sections included in the test.
The Construction group may have the cleaning procedure incorporated within the
integrity test procedure, if this is the case commissioning need to create a list of
system pipe lines to track progress.
If required a line by line valve by valve procedure needs to be written for a
cleanliness check, these procedures are to be written utilizing the piping isometrics
as a guide.

System list of pipe work to be cleaned

Project: System: Page

Author: P&ID’s:
PLEASE NOTE PRIOR TO THE CLEANING :
. All open pipe ends MUST be secured to avoid excessive movement.
. Always blow away from any vessels.
. Position target plates if required, to deflect debris to a safe location and or use as proof of cleanliness.
. All personnel not associated with the blow are to be removed from the area.
. All personnel involved with any high-pressure blow MUST wear ear protection.
. After the cleaning process, all open pipe ends MUST be closed to avoid recontamination. If pipe work is
left for a period, after the clean, then a visual inspection of the pipe needs to be done, prior to its
commissioning.
LINE DESCRIPTION TYPE OF CLEAN SIGNED / DATE
5. Equipment Check Sheets, off and on site checks

List of Vessel Check Sheets

1. Off site check – Tank or Drum

2. On site check – Tank or Drum
3. Off site check – Column
4. On site check – Column
5. Off site check – Rotating machinery
6. On site check – Rotating machinery
7. Auxiliary Systems – Lube oil, hydraulic systems, HVAC etc.
8. Off site check – Heat Exchangers
9. On site check – Heat Exchangers
10. Conveyer
11. Mill
12. Sieve
13. Pump
14. Fan/Blower
15. Furnace or Burner
16. Turbine

D-4
 e.g Off-Site Equipment Inspection
Check Sheet
Column/Tower

Equipment Title: Project:

System : Shop Location:
Author: Date: P&ID’s:
Vessel data sheet available? Y N
Step Item Yes No N/A Comments Sign &
Date
1 Check internal cleanliness
Clear of debris:
Dry:
Grease Free:
2 Check condition of lining.
3 Check orientation of assembled sections and
covers
4 Check installation and fitting of internal
components, where applicable
Packing grid supports
Bubbly cap trays
Bubble cap tray weirs
Bubble cap heights
Downcomer position and dimensions
Distributors
5 Feed nozzles and/or sprays
6 Check test joint material.
7 Witness pressure test.
8 Witness vessel drained and dry.
9 Witness leak test of assembled vessel
10 Demister pads fitted correctly
11 Flange finish as per vessel drawing
12 All branches fitted as per drawing
13 Ensure all temporary transportation brace is
identified
14
15
16
17
18
19
20
21

D-5
 Post Punch list
Check sheet

PLEASE NOTE: This sheet should be completed post the actual punchlist as an “Aide Memoir”.
This check sheet should never be used as a substitute to actually physically checking the system being punch
listed.

Checked
No Description & signed off Comments
1 Has this system been totally checked against the relevant
P&ID?

2 Has the pipeline finish been Insulation

fully checked? Painting
Trace Heating
Flange covers
Labels
3 Have potential hazards Splashing from drains
installation may have Air blow off points
created been considered? Potential for water pools,
(uneven surfaces)
Trip hazards, kerbs, pipes,
etc.
Noise
Headroom
4 Have all HAZOP actions that have had a construction
implication been considered?

5 Component check. Correct valve type as

specified
Correct gaskets in all
flanges
All In-line equipment correct
as specified
All bolts checked for
tightness
All internals fitted, e.g. Filter
elements, NRV internals
Other

6 Have all valves been checked for ease of operation, pinch

points and loose bonnet bolts?

7 Have all control valves been checked that they are fitted
correctly for direction of process flow?

D-6
 Checked
No Description & signed off Comments
8 Have all filters, Non-return valves and other in-line pieces
of equipment been checked that they are fitted correctly
for direction of process flow?
9 Have all vents and drains Safety of location
been checked to ensure? Access
Direction of exhaust
Splashing
Pooling
Space for blind flange
removal and flexible pipe
fitting is adequate
Are there sufficient drains
on pipe including manifolds
10 Have All grounding straps been checked, no loose
connections or loose bolts?
11 Have all instruments and Accessibility
electrical items been Can gauges be read
checked for? Do impulse lines and cables
create a hazard
Are junction boxes in the
way
Are all stop buttons
accessible, labeled and
guarded if necessary
Motor guards checked and
tight, no loose screws
Has all instruments been
labeled in the filed
12 Have All relief streams been Exhaust lines clear
checked? Labeled
Relief valves tested &
tagged
Bursting discs fitted and
tagged
Supports appear adequate
13 Have all pipelines been checked to ensure no visible
mechanical damage has been made?
14 Has a list of all scaffolding to be removed prior to handover
been made and added to the punch list?

D-7
 7. Action upon Alarm Sheet

ALARM ACTION SHEET

Alarm Title Loop Number P&ID Number

Settings Purpose of Alarm
Response time

POSSIBLE RESPONSES

CONSEQUENCES OF A FAILURE TO RESPOND

START UP/SHUT DOWN IMPLICATIONS

Author: Validated by: Date

D-8
 Documentation check sheet prior to
chemical introduction

Team Members: (Typical listed) PROJECT Author DATE

Project Manager -
Mechanical Engineer -
Electrical Engineer -
Process Engineer -
Operations Manager -
SHE Advisor -
Commissioning Manager -

No Section Guide word Comments and action Action On

1 Installation Has a check of pipe work, valves,
instrumentation configuration and
supports against P&ID’s and
isometrics been made?
Check equipment labeling, insulation
and valve numbering, testing and
labeling of stop and start buttons and
isolators.
Have correct materials of
construction been used.

2 Relief Systems Correctly installed and documented

to approved company and
standards.
Schedule of inspections in place.

3 Interlocks, All commissioning checklists and

Shutdown systems procedures completed.
and Alarms Interlock and shutdown test
procedures written
Practicality of test methods reviewed
and approved
List of persons responsible for
testing in place.
Alarm action review completed

Procedure in place for the control of

interlock and S/D defeats.

4 Restrictor orifices Are all in place, labeled, documented

or other flow and a system available to sustain.
restricting devices.
5 Equipment Check availability of equipment
Inspections manufacturer’s and independent
authorities test certificates.
6 HAZOP Have all requirements and actions
from the HAZOP been implemented
and completed

D-9
The following list details examples of pre-commissioning procedures that
commissioning can perform potentially during construction

Pre-Commissioning Procedure List

• Mechanical interlock checks

• Fitting of all locks on valves
• Checks to ensure check valves are fitted with internals
• Packing of a Distillation column
• Packing a Reactor with Catalyst
• Filling of desiccant into Drying Tower
• Installation of filter medium, cartridges etc.
• Checks to ensure pipe work falls in the correct direction
• Installation of filter bags into a Bag House or Dust
Collector
• Procedure to check flexible couplings and bellows are fit
for operation.
• Filling a Mill with Beads
• Procedures to check the operation without any chemicals
of a DCS control sequence

These procedures can be numbered such that they can be easily referenced
on a detailed commissioning schedule.

D-10
24. Commissioning Procedures

Commissioning procedures, written during the preparation phase of the project are
the documents which in great detail, set out how the plant will be commissioned and
started up.

It is common for the commissioning procedures to be written first, the SOP’s is

developed from these documents.

A detailed commissioning procedure should be compiled for each major activity that
the plant will undergo through the start-up. These documents are not check sheets,
they give a detailed descriptive of how the plant is made ready for normal operation.

Information to compose these procedures is found within, P&ID’s, PFD’s, process

descriptions, instrument data sheets, equipment data sheets, control narratives,
interlock and emergency shutdown descriptions, vendor installation and operating
manuals and most importantly talking with the process design teams.

A good commissioning procedure will detail the step, the method of performing the
step, any detail any relevant comments and observations.

Common procedures could be:

• How do we get the chemicals in?

• How to slowly heat up, cool down, vent and control pressure and non-
condensable gases,
• Introduce and control level
• Establish and control flow
• Manage exotherms and endotherms
• Condition a catalyst
• Set-up a distillation column for profile – diagrams on temperature/pressure
curve can be utilized
• Set-up and control of a scrubbing tower
• Actually introduce alarms conditions to test operability
• Introduce interlock conditions to test
• Describe and manage any DCS controlled sequences
• Normal and emergency shutdown – where applicable and possible
• Validation criteria and sampling regime

D-11
 COMMISSIONING TO PLANT
HANDOVER CERTIFICATE

The above checklist for handover to plant has been completed.

I am satisfied that the system work has been commissioned and it is safe to allow continued operation.

Commissioning Manager Print Date

Signature

Plant/Operating Manager Print Date

Signature

Reservations to Handover
Item No. Description of Outstanding Work Item ID Action Req. Priority
From

D-12
 267

APPENDIX E

POSSIBLE PROBLEMS, ANALYSIS

AND APPROPRIATE ACTION

 POSSIBLE PROBLEMS, ANALYSIS AND APPROPRIATE ACTION
Typical problems that may occur in a reactor system may include runaway
reaction,high reactor temperature, off-specification product, loss of heating or
cooling, tube rupture. high pressure drop across reactor bed, catalyst bed hot spots.

Runaway Reaction
A runaway reaction occurs when reaction temperature continues to rise even after full
cooling is applied to the reactor.
A runaway reaction can be caused by:

 loss of cooling.

 loss of agitation.

 changes in feed composition..

 excessive concentrations of catalyst.

 loss of reaction retarding chemicals.

 channelling in fixed bed reactors.

Actions taken to control a runaway reaction include:

 shutting down the reactor.

 reducing catalyst flow to reactor if catalyst is injected into the reactor.

 reducing flow of one reactant to reduce reaction rate.

 increasing flow of other reactant to dilute the reaction.

 shutting off heat supply to the reactor itself.

 cooling of the reactor.

Signs of reactor problems must be recognised at an early stage where action can be
 taken to prevent damage to equipment or injury to personnel.

High Reactor Temperature

A high temperature in the reactor can be caused by:

 loss of cooling.

 high catalyst concentration.

 incorrect feed composition.

Action taken to reduce high reactor temperature includes:

 shutting down the reactor.

 reducing catalyst flow to reactor if catalyst is injected into the reactor.

 reducing flow of one reactant to reduce reaction rate.

 increasing flow of other reactant to dilute the reaction.

 shutting off heat supply to the reactor itself.

 cooling of the reactor.

Off-specification Product
Product can become off-specification for many different reasons, but some factors
which can contribute to off-specification product are:

 sample taken was not a true representative sample or the sampling method
was incorrect.

 faulty instruments.

 feed variations.

 impurities in feed.

 poor catalyst quality or poisoned catalyst.

 incorrect mixing times or quantities.

 incorrect reactor temperature.

 leaking water jackets or coolant tubing which could contaminate the

reactants.

 incorrect maintenance procedures.

E-2
Loss of Heating or Cooling
Loss of heating or cooling in the reactor could be caused by:

 fouling of metal surfaces in heat exchanger tubes, water jackets or coils

preventing heat transfer.

 faulty steam traps causing condensation to build up in steam heating coils.

 heating or cooling medium not lined up to exchanger, water jackets or coils.

 sticking temperature control valve or faulty control circuit.

Tube Rupture
A tube rupture in a furnace reactor causes liquid feed or gaseous product to leak into
the firebox where the furnace burners can cause it to ignite.

High Pressure Drop

A high-pressure drop can occur across fixed bed reactors due to a flow restriction
caused by:

 coking and fouling of catalyst surfaces.

 catalysed bed collapsing due to high pressure.

Catalyst Bed Hot Spot
Pockets of stagnant reactants build up in the reactor bed due to uneven flow of
reactants through the bed.

Cooling circulation of fresh reactants is lost in these pockets, causing reaction

temperatures to increase above normal temperatures to create hot spots.

Channelling in Fixed Bed Reactor

Channelling occurs in fixed bed reactors when the reactants flow through some
sections of the reactor bed while bypassing other sections.
Channelling is caused by:

 Poor initial packing of the catalyst bed where catalyst is unevenly

distributed.

 Plugging of sections of the catalyst bed with solid dust or fines.

 Sudden gas surges through the catalyst bed or liquid slugs entering the
catalyst bed.

E-3
Channelling causes poor contact between reactants and catalyst resulting in
incomplete reaction and off-spec product.

Channelling can be partially compensated for by adjusting flow rate and temperature
parameters, but the only permanent solution to channelling is to dump the catalyst and
re-pack the catalyst bed with fresh catalyst.

Corrective Action
Once problems are identified in a reactor, corrective action can be applied as follows:

Reactor Problem Action Taken to Correct Off-Specification Product

Improper Sample If operating parameters appear normal, take new samples and have
them analysed.

Faulty Instruments Test the critical instruments used to measure temperatures,

pressure and flows, then repair or replace any faulty instruments.

Feed Variations or Take a new feed sample for analysis and compare the results
Impurities in Feed against the initial feed sample.

 Any change in feed composition or properties will

require reactor operating parameters to be trimmed to
prevent off-spec product.

 Any impurities in the feed that adversely effects the

reactions must be removed or feed taken from an
alternative source.

Faulty Wrong materials used during maintenance or incorrect assembly

Maintenance can adversely effect the reactions or catalyst.
A maintenance shutdown will have to be scheduled to inspect
reactor intervals and make repairs as required.

Incorrect Mixing Procedures must be followed to ensure:

Times or Feed  correct quantities and proportions of reactants and
Mixtures catalyst are used.
 correct mixing times are adhered to.

E-4
Reactor Problem Action Taken to Correct Off-Specification Product

Leaking water Equipment suspected of leaking must be pressure tested to find

jackets or leaks. Leaky water jackets or exchanger must be repaired to
exchangers prevent contamination of reactants and product.

Poor Quality Catalyst must be changed over.

Catalyst

Fouling of metal Check temperature rise or fall across the heat exchanger, water
surfaces in heat jackets or tubes. If temperature rise or fall is less than normal,
exchangers/water fouling has occurred which will require:
jackets or tubes.  washing internal surfaces of exchangers, water jackets or
coils with cleaning solution then flushing with water or
steam to remove cleaning solution.
 flushing with water or steam to remove cleaning solution.

Faulty Steam Repair or replace steam traps.

Traps

Heating or cooling Ensure valve line-up to and from exchangers is correct and valves
medium not lined are fully open.
up to exchanger,
water jackets or
tubes.

Sticking  lubricate, service and test control valve.

temperature  test control circuit.
control valve or
faulty control
circuit.

Tube rupture in  shut off fuel to the burners.

furnace reactor.  shut off feed to the furnace.
 purge furnace with steam or inert gas.
 prepare furnace for confined space entry and
maintenance
 repair or replace damaged tubing.

E-5
Reactor Problem Action Taken to Correct Off-Specification Product

High pressure drop  regenerate the catalyst to remove coke.

across catalyst bed.  replace catalyst.

Hot spots in  check flow rate of reactants to the reactor is normal

reactor bed - low flow rates can cause uneven circulation
through the reactor.
 unblock distributor plate at base of reactor bed.
 remove chunks or other obstructions from reactor.

Channelling  adjust flow rate and temperature parameters to obtain on-

spec product.
 dump the catalyst and pack the bed with fresh catalyst.

Follow up items initiated until resolved.

Even if the problem has been passed on to others to find and implement solutions,
follow up is essential – this makes sure that the problem is not lost in the system.

Always report problems outside of your responsibility and ensure that it is reported
and passed on to the appropriate person.

Where a shutdown will affect upstream or downstream process units, advanced

warning must be given to appropriate personnel to allow them to prepare for, and
react to, changing conditions. This would generally include suppliers of utilities and
feed stocks, and the downstream units that receive the various product streams.
Sufficient warning time needs to be given to allow these other areas to be ready for
the shutdown, and to have alternative disposal or storage ready when needed.

E-6
 The shutdown will occur
at 1500 hours

Advanced warning of shutdowns must be communicated

In the case of emergency shutdowns or process trips, there is not time to give
advanced warnings, but communication must be made with unit suppliers and
customers as soon as possible after the trip or emergency shutdown to minimise the
adverse effects of the shutdown.

E-7