BASIC DESIGN ON CONVERSION OF WASTE PLASTIC INTO

FUEL OIL AND FUEL GAS

Final Project Report Submitted

By

Sachin Banzade Reg. No.: 019054-15

Saroj Raj Kafle Reg. No.: 019060-60

Sudip Sharma Reg. No.: 019071-15

DEPARTMENT OF CHEMICAL SCIENCE AND ENGINEERING

SCHOOL OF ENGINEERING

KATHMANDU UNIVERSITY

SEPTEMBER 2019
 BONA FIDE CERTIFICATE
This is to certify that the project titled Basic Design on Conversion of Waste Plastic into Fuel
Oil and Fuel Gas is a bona fide record of the work done by

Sachin Banzade Reg. No.: 019054-15

Saroj Raj Kafle Reg No.: 019060-15

Sudip Sharma Reg. No.: 019071-15

in partial fulfillment of the requirements for the award of the degree of Bachelor of Engineering
in Chemical Engineering of the Kathmandu University, Dhulikhel during the year 2019.

Assist. Prof. Dr. Bibek Uprety Assoc. Prof. Dr. Rajendra Joshi

Supervisor Head of Department

Department of Chemical Science & Engineering Department of Chemical Science & Engineering

____________________________ _________________________

Internal Examiner External Examiner

Project Viva-voce held on 23rd September, 2019

ACKNOWLEDGMENT

We would like to make this an opportunity to transfuse our appreciation to everyone who was
behind the successful completion of this design. First and foremost, we would like to thank
“Department of Chemical Science and Engineering Department” for accepting our design project.

Kindest regard goes to Assoc. Prof. Dr. Rajendra Joshi, Head of Department of Chemical
Science and Engineering for allowing us to accomplish the design project.

We would like to convey appreciation to our supervisor, Assist. Prof. Dr. Bibek Uprety, for his
encouragement and motivation to expand our vision regrading proper process designing. We are
very thankful for his help and supervision. This task would have been little success without his
proper guidance and support.

Also, we are always very grateful to Prof. Dr. Kyun Young Park, visiting professor for always
guiding and encouraging us to do best.

Last but not the least, we are thankful to our fellow colleague of our department for their friendly
support given to accomplish this project successfully and our family members for always providing
the best guidance possible.

A big thanks to you all.

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ABSTRACT

Plastic is an outcome of petroleum industry. Most of the plastics are recyclable but some are not
due to their chemical structure and physical parameters. Pyrolysis is the thermochemical
decomposition of plastics at elevated temperatures (in absence or little supply of oxygen) into a
range of useful products. The system, here, is so designed to pyrolyze only Poly Propylene, Poly
Ethene and Poly Styrene plastics. The plastic pyrolysis should be able to process 3.2 tons of plastics
each day.

These waste plastics consisting of PP, PE and PS, are first sorted manually and chipped and various
solid transportation process are carried out using various Programming Logic Controller
equipment and finally feed in the reactor filled with E-cat catalyst enclosed in fire husk burner
maintaining reaction temperature about 400 °C with residence time two seconds. Nitrogen gas is
used to create inert environment and for fluidization in reactor. The produced cracked gas is now
sent to be condensed to a condenser followed by the series of cyclone separator and electrostatic
precipitator then finally feed into the liquid vapor separator.

The produced cracked product consists of about 80% fuel gas, and 7% fuel oil and remailing as
solid char. The produced fuel oil can further be processed to produce synthetic fuel oil. The
synthetic fuel oil has lower carbon emission ratio, this can on one hand manage the waste plastic
problem to some extent and on other hand can also reduce global warming process.

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Table of Contents

ACKNOWLEDGMENT ............................................................................................................................. i
ABSTRACT ................................................................................................................................................. ii
List of Figures............................................................................................................................................. vi
List of Tables ............................................................................................................................................. vii
1. INTRODUCTION............................................................................................................................... 1
1.1 Scope of the project ..................................................................................................................... 3
1.2 Limitations of project ................................................................................................................. 3
2. BACKGROUND ................................................................................................................................. 4
2.1 Plastics.......................................................................................................................................... 4
2.2 Types of Plastics .......................................................................................................................... 5
i. Polyethylene Terephthalate (PET/PETE) ................................................................................. 5
ii. High-Density Polyethylene (HDPE) .......................................................................................... 5
iii. Polyvinyl Chloride (PVC) ........................................................................................................... 6
iv. Low-Density Polyethylene (LDPE) ............................................................................................ 7
v. Polypropylene (PP) ..................................................................................................................... 8
vi. Polystyrene (PS) .......................................................................................................................... 8
vii. Code 7........................................................................................................................................... 9
2.3 Effect of Plastics .......................................................................................................................... 9
2.4 Plastics Disposal Approaches ................................................................................................... 11
2.5 Plastics Waste Management Approach in Nepal ................................................................... 13
2.6 Classifications of Reactor ......................................................................................................... 13
2.7 Types of Pyrolysis ..................................................................................................................... 15
2.8 Pyrolysis Kinetics ...................................................................................................................... 16
2.9 Merits and Demerits of Fluidized Bed Catalytic Pyrolysis Reactors ................................... 18
2.10 Catalyst and Pyrolysis .............................................................................................................. 19
3. DESIGN BASIS ................................................................................................................................. 21
3.1 Feed Specification ..................................................................................................................... 21
3.2 Utilities Requirements .............................................................................................................. 21
3.3 Regulation for Safety and Environment ................................................................................. 22
3.4 Design Codes.............................................................................................................................. 22
4. PROCESS DESCRIPTION ............................................................................................................. 23
4.1 Fluidization Theory .................................................................................................................. 26

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5. PROCESS FLOW DIAGRAM ........................................................................................................ 28
6. PIPING AND INSTRUMENTATION DIAGRAM ....................................................................... 30
7. CALCULATION AND DESIGN ..................................................................................................... 33
7.1 Fluidized Bed Reactor .............................................................................................................. 33
7.1.1 Mass Balance for the Reactor ............................................................................................................. 33
7.1.2 Energy Balance for the Reactor .......................................................................................................... 34
7.1.3 Design of Fluidized Bed Reactor ........................................................................................................ 38
7.2 Husked Fired Furnace Design ................................................................................................. 40
7.2.1 Energy Balance Calculation and Design ............................................................................................ 40
7.2.2 Stack Design ......................................................................................................................................... 42
7.3 Condenser Design Calculation ................................................................................................. 42
7.3.1 Tube Side Heat Transfer Coefficient ................................................................................................. 44
7.3.2 Shell Side Coefficient ........................................................................................................................... 45
7.3.3 Overall Calculated Heat Transfer Coefficient .................................................................................. 46
7.3.4 Pressure Drop Calculation .................................................................................................................. 46
7.4 Pipe Diameter Calculation ....................................................................................................... 47
7.5 Design Calculation of Liquid Vapor Separator...................................................................... 48
7.6 Design Calculation of Cyclone Separator ............................................................................... 48
7.7 Design Calculation of Electrostatic Precipitators .................................................................. 50
8. EQUIPMENT LISTS........................................................................................................................ 51
9. INSTRUMENT LIST ....................................................................................................................... 52
10. SPECIFICATION SHEETS ........................................................................................................ 54
10.1 Specification Sheet for Fluidized Bed Reactor ....................................................................... 54
10.2 Specification Sheet for Heat Exchanger.................................................................................. 56
10.3 Specification Sheet for Husk Fired Furnace ........................................................................... 57
10.4 Specification Sheet of Gas-Liquid Separator ......................................................................... 59
10.5 Specification Sheet for Glove Valve ........................................................................................ 61
10.6 Specification Sheet for Electro-Static Precipitator ................................................................ 62
10.7 Specification Sheet for Cyclone Separator ............................................................................. 63
10.8 Equipment Controlled by Programmable Logic Controller ................................................. 64
10.9 List of Valves and their Specifications .................................................................................... 65
10.10 Piping and Insulation Specification ..................................................................................... 66
11. ECONOMIC ANALYSIS............................................................................................................. 67
11.1 Estimation of Fixed Capital Investment ................................................................................. 69
11.2 Working Capital Estimation .................................................................................................... 70

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 11.3 Payout Period ............................................................................................................................ 73
11.4 Rate of Return (ROR)............................................................................................................... 73
12. SAFETY ANALYSIS.................................................................................................................... 74
12.1 Fire Prevention .......................................................................................................................... 74
12.2 Chemical Toxic Prevention ...................................................................................................... 75
12.3 Physical Aspects ........................................................................................................................ 75
12.4 HAZOP Analysis ....................................................................................................................... 76
13. RECOMMENDATION ................................................................................................................ 82
14. CONCLUSION ............................................................................................................................. 83
15. REFERENCE ................................................................................................................................ 84
16. APPENDIX .................................................................................................................................... 86
16.1 Appendix A: Abbreviation ....................................................................................................... 86
16.2 Appendix B: Constant Values and Nomenclature ................................................................. 89
16.3 Appendix C: Instruments Symbol ........................................................................................... 93
16.4 Appendix D: Equipment Symbol ............................................................................................. 93

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List of Figures

Figure 1. Plastic Production Per Year. Source: Darrin Qualman .................................................................. 1

Figure 2. PET Bottle. Source: Mould and Die World Magazine .................................................................. 5
Figure 3. HDPE produce. Source: Plastic Today .......................................................................................... 6
Figure 4. PVC product. Source: Green and Growing ................................................................................... 7
Figure 5. Single use Polyethene. Source: Polymer Solutions ....................................................................... 7
Figure 6. Bottles Produces by PP. Source: Chemical News ......................................................................... 8
Figure 7. Polystyrene Plastic Products. Source: Go Dok .............................................................................. 9
Figure 8. Landfilling. source: European Union-EP .................................................................................... 11
Figure 9. Incineration of Plastics in Open Environment. Source: Google.com .......................................... 12
Figure 10. Waste to Energy. Source: Google.com ...................................................................................... 12
Figure 11. Reaction assumed to be followed to produce gas, oil and char ................................................. 17
Figure 12. General Process Flow Diagram ................................................................................................. 24
Figure 13. Schematic representation of the different regimes of fluidized bed by Kunni and Levenspiel . 27
Figure 14. Process Flow Diagram of Plastics Pyrolysis Plant .................................................................... 29
Figure 15. Piping and Instrumentation Diagram for Plastic Pyrolysis Diagram ......................................... 30
Figure 16.Piping and Instrumentation Diagram for Mechanical Process ................................................... 31
Figure 17. Piping and Instrumentation Diagram for Chemical Process ...................................................... 32

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List of Tables

Table 1. Suitability of Plastics for Pyrolysis .............................................................................................. 16

Table 2. Yield of Different Combinations of Plastics ................................................................................. 18
Table 3. Feed Specification......................................................................................................................... 21
Table 4. Product Specification ................................................................................................................... 25
Table 5. Enthalpy of Formation of Reactant ............................................................................................... 36
Table 6. Enthalpy of Formation of Products ............................................................................................... 36
Table 7. Equipment List .............................................................................................................................. 51
Table 8. Instrument List .............................................................................................................................. 52
Table 9. Specification Table for Pyrolysis Reactor .................................................................................... 54
Table 10. Specification Sheet for Heat Exchanger ..................................................................................... 56
Table 11. Specification Sheet for Husk Fired Furnace ............................................................................... 57
Table 12. Gas-Vapor Separation Unit Specification Sheet ......................................................................... 59
Table 13. Glove Valve Specification Sheet ................................................................................................ 61
Table 14. Specification Sheet for Electro-Static Precipitator ..................................................................... 62
Table 15. Specification Sheet for Cyclone Separator ................................................................................. 63
Table 16. Equipment Controlled by PLC.................................................................................................... 64
Table 17. Valves with their Specification ................................................................................................... 65
Table 18.Piping and Insulation Specification ............................................................................................. 66
Table 19. Fixed Capital Investment Estimation .......................................................................................... 69
Table 20. HAZOP Analysis ........................................................................................................................ 76
Table 21. Symbols and their Meaning ........................................................................................................ 89
Table 22. Instrument Symbol ...................................................................................................................... 93
Table 23. Equipment Symbol...................................................................................................................... 93

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1. INTRODUCTION

Plastics have reached a pinnacle of use ever since the 20th century development of petroleum
industries. Plastics are everywhere from the top of Mount Everest to deep under the sea. Mount
Everest has about one hundred thousand kilograms of plastics and ocean contains about 1.5 billion
tons of plastics. Plastics pieces were found recently even in the inhabited Artic region. The plastics
scraps are found as deep as 150 kilometers into the ocean. Most of these plastics are non-
biodegradable. They are the result of human dumped plastics that make their way into the seas and
oceans. Plastics produce harmful toxins which effect life in soil, water and air. All the major
countries in the world including Nepal are facing huge problems of plastic wastes.

Plastic is an outcome of petroleum industry. Most of the plastics are recyclable but some are not
due to their chemical structure and physical parameters. Since early 1950s, the production of
plastics has grown from 2 million tons to 400 million tons per year.[1]

The concerning part is the fact that about 80% of the plastics are wasted within a year of production
and become worthless within the next four years. They are mostly dumped in the environment,
either on the land or in the ocean. The plastics dumped on land eventually reach ocean by one
means or another.

Figure 1. Plastic Production Per Year. Source: Darrin Qualman

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The problem of plastics is real and needs immediate action for its controlled use and its proper
disposal. Among various ways to manage plastics, recycle, reuse and reduce are supposed to be
[2]
the primary management methods. Cities like Illam, Damak, Palpa and Pokhara have banned
the use of one-time-use plastics completely. But, better ways of plastics management are being
researched. Some of innovative ideas include using processed plastics pieces along with asphalt to
pave roads and converting plastics pieces into fiber to produce plastic fiber carpets. Yet other
engineering techniques like pyrolysis convert plastics into useful fuel oil and gases.

Pyrolysis is the thermochemical decomposition of plastics at elevated temperatures (in absence or

little supply of oxygen) into a range of useful products. It involves the breaking down of large
complex hydrocarbon chains into relatively simpler molecules of gas, liquid and char. Pyrolysis
of plastics usually takes place in a low temperature range of 300 to 650 °C. [3] The general process
involves burning dry and small pieces of plastics in an inert environment inside a reactor. In
contrast, plastics burned in presence of oxygen produce the lesser desired carbon dioxide and
carbon monoxide.

The composition of pyrolysis product depends most notably on pyrolysis temperature and heating
rate. Higher temperature and heating rate result in the formation of greater proportion of biogas
and bio-oil while lower pyrolysis temperature and heating rate result in greater proportion of char.
The initial pyrolysis product consists of condensable gases and solid char. The condensable gas
can be further broken down into char, fuel oil and non-condensable gases (CO, CO2, H2 and CH4).

The primary objective of this project is to design a pyrolysis plant based on the amount of wastes
generated for the city of Kathmandu. The plant aims to produce about 2.5 tons of fuel gas, 0.224
tons of fuel oil per day from an estimated 3.2 tons waste per day.[4] The same equipment and
process design can also be applied to effectively manage plastic wastes in other major cities of
Nepal.

The detailed process design of the pyrolysis technique along with equipment sizing and costing,
utility requirements for running the plant are included in this report.

2
1.1 Scope of the project

Plastics are nearly perennial. So, it has long term use and can produce clean energy. The produced
fuel oil, if used in combination of pure oils in the form of synthetic fuel oil, helps minimize
production of carbon dioxide as well. The plastic pyrolysis should be able to process 3.2 tons of
plastics each day producing 80.3% of fuel gas, 7.4% of fuel oil and about 12.3% of solid residue
(char). The volume of designed reactor is 1.71 m3. The required capital investment is about 17
crore and production cost could be about 24 crores.

1.2 Limitations of project

The system is so designed to pyrolyze only PP, PE and PS plastics. This plant cannot pyrolyze
other any kind of plastics. The polyvinylchloride should not be present in the feed even in the trace
amount. If present, hydrochloric acid could be formed which could corrode and damage the plant.
Due to the lack of experimental data on plastic pyrolysis for Nepal, the process calculations are
based on literature data from other countries which may be little different in the field. The plastics
separation on exactly the required proportion is somewhat not possible all the times. This could
hamper the exact quantity of fuels productions. The catalyst regeneration process is not described
due time limitations for this project.

3
2. BACKGROUND

The present scenario of plastic waste in Nepal is also no different. In Nepal, 16 percent of urban
waste comprises of plastics, which is about 2.7 tons of daily plastic garbage production. 30% of
the total plastics used are single use polyethene bags. The amount of plastic use and their
production rate is increasing in Nepal. A study shows that the growth of plastic industry was about
11% in 2015-2016.[5] Recently, about 11,000 kilograms of plastics were collected and cleared from
Mount Everest by locals. This is just part of the total amount of trash left behind by the
mountaineers while climbing the summit. Kathmandu, capital of Nepal, is also facing huge
problem of plastic management. Major cities like Janakpur, Biratnagar, Birgunj, Butwal, etc. are
also fighting plastic waste problem every day. Nearly 3 tons of plastics produced daily in urban
cities in Nepal are almost dumped in the land filling sites. The plastics thrown here and there in
the city is hampering the beauty as well as is the source of epidemics. Meanwhile, the floods in
Bhaktapur this year were partly blamed on plastic garbage blocking the drains.

The rampant use of plastics is creating havoc. The endless toxicity and long-term disadvantage of
plastics to our nature and environment has concerned us. The extensive use of plastics must be
given a second thought. The problems due to plastics should be mitigated before it is too late. So,
one of the better options could be pyrolysis of plastics using catalyst like ECat or zeolite. This
project mainly focuses on design of plastics pyrolysis plant with a capacity of about 3.2 tons per
day.

2.1 Plastics

Plastics are synthetic and semisynthetic organic polymer. While other elements might be present,
plastics always include carbon and hydrogen.[6] Plastic polymers consist of chains of linked
subunits, called monomers. If identical monomers are joined, it forms a homopolymer. Difference
monomers link to form copolymers. Homopolymers and copolymers may be either straight chains
or branched chains. Plastics are usually solids. They may be amorphous solids, crystalline solids,
or semi-crystalline solids (crystallites). Plastics are usually poor conductors of heat and electricity.
Most are insulators with a high dielectric strength. Glassy polymers tend to be stiff (e.g.,

4
polystyrene). However, thin sheets of these polymers can be used as films (e.g., polyethylene).
Nearly all plastics display elongation when they are stressed that is not recovered after the stress
is removed. This is called "creep”. Plastics tend to be durable, with a slow rate of degradation.
Very light weight and durable and strong, because of all those properties of plastics, they are used
extensively.

2.2 Types of Plastics

On the basis of recycling code provided by Society of Plastics Industry (SPI), plastics can be
divided into seven categories:

i. Polyethylene Terephthalate (PET/PETE) [7]

PET, also called PETE, is produced by the polymerization of ethylene glycol and terephthalic
acid. Items made from this plastic are commonly reused. PET(E) plastic is used to make many
common household items like beverage bottles, medicine jars, rope, clothing and carpet fiber
(Figure 2).

Figure 2. PET Bottle. Source: Mould and Die World Magazine

ii. High-Density Polyethylene (HDPE) [7]

HDPE is manufactured at low temperatures and pressures, using Ziegler-Natta and metallocene
catalysts or activated chromium oxide (known as a Phillips catalyst). The lack of branches in

5
 its structure allows the polymer chains to pack closely together, resulting in a dense, highly
crystalline material of high strength and moderate stiffness. High-Density Polyethylene
products are very safe and are not known to transmit any chemicals into foods or drinks. HDPE
products are commonly recycled. Items made from this plastic include containers for milk,
motor oil, shampoos and conditioners, soap bottles, detergents, and bleaches. It is NEVER safe
to reuse an HDPE bottle as a food or drink container if it didn’t originally contain food or drink
(Figure 3).

Figure 3. HDPE produce. Source: Plastic Today

iii. Polyvinyl Chloride (PVC) [7]

Polyvinyl Chloride is sometimes recycled. Vinyl chloride (CH2=CHCl), also known as

chloroethylene, is most often obtained by reacting ethylene with oxygen and hydrogen chloride
over a copper catalyst. It is a toxic and carcinogenic gas that is handled under special protective
procedures. PVC is used for all kinds of pipes and tiles, but is most commonly found in
plumbing pipes. This kind of plastic should not come in contact with food items as it can be
harmful if ingested.

6
 Figure 4. PVC product. Source: Green and Growing

iv. Low-Density Polyethylene (LDPE) [7]

Low Density Polyethylene is sometimes recycled. LDPE is prepared from gaseous ethylene
under very high pressures (up to about 350 megapascals, or 50,000 pounds per square inch)
and high temperatures (up to about 350 °C [660 °F]) in the presence of oxide initiators. These
processes yield a polymer structure with both long and short branches. Because the branches
prevent the polyethylene molecules from packing closely together in hard, stiff, crystalline
arrangements, LDPE is a very flexible material. It is a very healthy plastic that tends to be both
durable and flexible. Items such as cling-film, sandwich bags, squeezable bottles, and plastic
grocery bags are made from LDPE.

Figure 5. Single use Polyethene. Source: Polymer Solutions

7
v. Polypropylene (PP) [7]

Polypropylene is occasionally recycled. Polypropylene, a synthetic resin, is built up by the

polymerization of propylene. One of the important family of polyolefin resins, polypropylene
is molded or extruded into many plastic products in which toughness, flexibility, light weight,
and heat resistance are required. It is also spun into fibers for employment in industrial and
household textiles. PP is strong and can usually withstand higher temperatures. It is used to
make lunch boxes, margarine containers, yogurt pots, syrup bottles, prescription bottles. Plastic
bottle caps are often made from PP.

Figure 6. Bottles Produces by PP. Source: Chemical News

vi. Polystyrene (PS) [7]

Polystyrene is commonly recycled, but is difficult to do. Polystyrene, a hard, stiff, brilliantly
transparent synthetic resin produced by the polymerization of styrene. Styrene is obtained by
reacting ethylene with benzene in the presence of aluminum chloride to yield ethylbenzene.
The benzene group in this compound is then dehydrogenated to yield phenyl-ethylene, or
styrene, a clear liquid hydrocarbon with the chemical structure CH2=CHC6 H5. Styrene is
polymerized by using free-radical initiators primarily in bulk and suspension processes,
although solution and emulsion methods are also employed. Items such as disposable coffee
cups, plastic food boxes, plastic cutlery and packing foam are made from PS.

8
 Figure 7. Polystyrene Plastic Products. Source: Go Dok

vii. Code 7 [7]

Code 7 is used to designate miscellaneous types of plastic not defined by the other six codes.
Polycarbonate and Polylactide are included in this category. These types of plastics are
difficult to recycle. Polycarbonate (PC) is used in baby bottles, compact discs, and medical
storage containers.

2.3 Effect of Plastics [16]

Plastics normally need at least of 500 years to self-decompose. It easily lasts more than 5
generations. They never go away. The chemicals like BPA, phthalates, antimony, arsenic, etc.
present in the plastics are very toxic to human health. Plastics directly or indirectly affect human
health in various series. Once plastics are deposited in the dumping or any other sites, they attract
further more pollutants. The organic and inorganic, degradable as well as non-degradable wastes
get further more deposited. Plastics do not get decomposed easily, so they accumulate in the
environment. They pile up and are reason for various diseases. Recently, traces of plastics were
found in the human guts. Similarly, larger sizes of plastics are consumed by aquatic animals.
They enter the food chain, disrupt it and destroy the human and earth’s environment. Plastics are
never easy to decompose, recycle, or reduce. Although they can be used to produce fuel oil and
fuel gas, it is very complicated. It requires huge investments. All the plastics cannot be converted
to fuel oil and gas too.

9
Furthermore, Plastics contain some harmful chemicals which are toxic to human as well as
organism’s health. Chemicals present in plastics which are mostly harmful are:

a. Bisphenol A (BPA)
Polycarbonate plastics products are manufactured using BPA. Plastics tableware, bottles
for drinks, sports equipment, etc. are manufactured using polycarbonate plastics which
contain BPA. BPA is classified as endocrine disruptor, which means it has toxic effect on
our ability to reproduce.

b. Phthalates
Phthalates are used as plastic softeners to make plastics more flexible. These phthalates are
also found to be endocrine disruptors.

c. Antimony Trioxide
Antimony contributes to cancer development, skin problems, menstrual and pregnancy
problems.

The growth of population of the human race and their extensive use of plastics and petroleum has
caused the environment to change drastically. The temperature of earth has increased by 10 °C in
2018 A.D. from that the temperature of earth during 1981 to 2000 A.D. long term average. If the
temperature of Earth keeps on increasing on this rate, the Earth’s climate would be destroyed and
the exceed the point of no return within next 200 years.

Today, the world is facing with issues because of the limited availability of the resources to fulfill
the expectations of the each and every human being. In order to overcome this issue, the scientists
and researchers have developed three key technologies, namely,

i. Reduce
ii. Reuse
iii. Recycle

The process of converting plastics into fuel oil and gas can, in a broad sense, be taken as recycling
process. The plastics are converted into alkane and alkanes. In the plant design of converting waste

10
plastic into fuel, the major equipment such as reactors comprising fired heater or burner, shredders,
heat exchangers, condenser or flash distillation column, etc. must be individually designed.

2.4 Plastics Disposal Approaches

Mainly, plastics are disposed in three general ways.

i) Landfilling [17]
The most common plastic disposal approach followed in recent times is landfilling. All the
plastics are collected and are disposed in any open space without proper management. This
technique of plastic disposal is most hazardous and can contaminate land, water as well as
air. Every possible part of Earth is affected by this method. Every year millions and
millions of tons of waste plastics are dumped in the open space. Nepal also follows this
technique ineffectively.

Figure 8. Landfilling. source: European Union-EP

ii) Incineration [17]

Another method of disposal of waste plastics is incineration. Waste plastics are collected
in the open space and simply burned. This method is even more hazardous as it produces
carbon monoxide and carbon dioxide as well as compounds like CFCs, Sulphur dioxides,
etc. The huge production of carbon dioxides directly helps in increasing the temperature of

11
 environment and the Earth as a whole. Climate change as well as global warmings are
caused due to excess production of such compounds. Controlled incineration producing
least amount of such compounds are highly recommended.

Figure 9. Incineration of Plastics in Open Environment. Source: Google.com

iii) Conversion to Energy [17]

The most effective way of plastic disposal should be converting it into energy source. As
energy consumption is increasing each year exponentially, plastics wastes should be used
to produce energy as much as possible. Plastics can produce fuel oil and fuel gas if properly
pyrolyzed which is huge source of energy.

Figure 10. Waste to Energy. Source: Google.com

12
2.5 Plastics Waste Management Approach in Nepal

Nepal mostly follows the general method of waste management, that is, three R’s.
a) Reuse
b) Recycle
c) Reduce

These techniques are not utilized in proper manner and only about 5% of total plastic waste go
through this process. Remaining plastics are mostly dumped on the landfills. The environment gets
polluted and affects the general lifecycle of the organisms. Project to manage the plastics like green
road waste management technique was also tested. But the sheer amount of investment and its
long-term effectiveness caused the project to discontinue. Other engineering techniques like
pyrolysis could also be used for waste management in Nepal. This project is small step toward the
establishment of plastic waste conversion plant set-up. Plastic are long term problem and these
must be solved as soon as possible either by searching for its alternatives or by converting these
plastics into something useful. As long as the petroleum industry are functioning, the source of
plastic is never lost which is hundreds of years from now. So, the huge amount of plastics already
dumped must be recycled in any way and what better way to recycle than by converting it into fuel
oil and fuel gas.

2.6 Classifications of Reactor

On the basis of mode of operation, pyrolysis reactor can be classified as:

i) Batch Reactor [15]

In batch reactors, all the chemical regents are added in the beginning and when the reaction process
proceeds, the composition changes with time. When the reaction is done, the process is stopped
and the product at the required composition will be withdrawn. Batch processes are very suitable
for the small-scale production processes.

13
ii) Continuous Reactor [15]
In continuous reactors, the chemical regents are added continuously and the product also
withdrawn continuously. Hence the continuous reactors operate under the steady state conditions;
they normally give lower production and maintenance cost than the batch reactors.

iii) Semi-batch Reactor [15]

In semi-batch reactors, a certain portion of chemical regents is added or a certain portion of the
product is removed during the process. In semi-continuous reactors, the process will be interrupted
periodically for some purpose. E.g. Regeneration of catalysts.

On the basis of reaction process, reactors are as follows [15]:

➢ stirred tank reactor
➢ tubular reactor
➢ packed bed
➢ fluidized bed

Stirred tank reactors generally consist of a tank fitted with a separate mechanical agitator and a
cooling jacket or coils. They can be operated in batch as well as continuous processes.

Tubular reactors generally used for gaseous reactions. They are also suitable for some liquid-
phase reactions. They are also called as plug flow reactors.

There are two basic types of packed bed reactors. One is where the solid is a reactant and the
other is where the solid is a catalyst. Among them, the packed bed reactors in which the solid is
used as a catalyst are recommended and generally used by the designers. Packed bed reactors are
not recommended for the reactions which have high heat-transfer rates.

Fluidized bed reactors are used for the high heat transfer rate reactions where mainly catalysts
are reacted inside the fluidized bed and then transferred to another vessel for regeneration.

14
 2.7 Types of Pyrolysis

Pyrolysis can be broadly classified into slow, flash and fast pyrolysis based on the processing
time and temperature of raw material.

i. Slow Pyrolysis [3]

Slow pyrolysis is characterized by low temperatures, slow biomass heating rates and lengthy solids
and gas residence times. In slow pyrolysis, the heating temperature ranges from 0.1 ℃ to 2 °C per
second and the plastic is subjected to temperatures near 500 °C. The gas residence time may be
over five seconds while that of plastic may range from minutes to hours. During slow pyrolysis,
char is released as the main product of the pyrolysis process.

ii. Flash pyrolysis [3]

Flash pyrolysis occurs at moderate temperatures between 400 ℃ and 600 ℃ and very rapid heating
rates. The vapor residence time in flash pyrolysis is less than 2 seconds. Flash pyrolysis produces
fewer amounts of tar and gas when compared to the slow pyrolysis process.

iii. Fast Pyrolysis [3]

In fast pyrolysis, the main products of the pyrolysis process are gas and oil. The plastic is heated
to about 500 °C or higher depending on the desired amount of oil or gas. The peak temperature
can be up to 1000 °C if gas is the product of interest. Fast pyrolysis is characterized by
• High heating rate.
• Reaction temperature within 425 to 600 °C.
• Short Vapor residence time of < 3 seconds.
• Rapid quenching of the product gas.

Pyrolyzers have historically been used to produce charcoal. Early pyrolyzers maximized charcoal
production by employing slow heating rate, longer residence time and were operated in batch
process mode. The pyrolysis temperature and duration of pyrolysis were also adjusted accordingly
to obtain the desired product composition and yield.

15
Modern pyrolyzers may be operated in continuous or batch mode with emphasis on producing
gaseous and liquid products. The type of reactor to be used in each pyrolysis application is
dependent on the type of pyrolysis and the heat transfer requirement. There has been improvement
in pyrolysis design, development and implementation over the last twenty-five years. Based on the
gas-solid contacting mode, pyrolyzers can be classified into fixed bed, fluidized bed and entrained
bed. It can be further subdivided depending on the pyrolysis type the design is intended.

The latest, optimized and economically viable process in conversion of waste plastic into fuel oil
and gas in the current scenario are the fluidized bed catalytic pyrolysis process. In this process a
selected catalyst, ECat or ZSM-5, is introduced into the pyrolysis reactor and because of the high
velocity of the fluid, the catalyst particles will flow upwards and then regenerated by a separate
regeneration unit. It will reduce the activation energy of the decomposition process so that the
decomposition temperature can be reduced drastically.

2.8 Pyrolysis Kinetics

Not all the plastics can undergo pyrolysis and produce fuel gas and oil. So, selected plastics
should be passed into the pyrolysis reactor. The suitability of plastics is determined by different
lab analysis and understanding the chemical composition of plastics in general.

Table 1. Suitability of Plastics for Pyrolysis [9]

Resin Suitability
Polyethylene Very good
Poly propylene Very good
Polystyrene Very good
Polyvinyl chloride Not suitable
Polyethylene- Terephthalate Not suitable

16
 Figure 11. Reaction assumed to be followed to produce gas, oil and char

Let us consider the mixture of the plastics which undergoes catalytically, thermally cracking to
form Gas (G), Oil (s) and char (C) with rate constants k1, k2 and k3 respectively. P, G, S, C and A
are the mass of plastics, Gas, Oil, Char and total solid remaining at time t. [8]

𝑑𝑃
= − (k1 + k2 + k3) * 𝑃
𝑑𝑡

𝑑𝐺
𝑑𝑡
= k2 * 𝑃

𝑑𝐶
= k3 * 𝑃
𝑑𝑡

𝑑𝑀 𝑑𝑃 𝑑𝐺 𝑑𝐶
= + +
𝑑𝑡 𝑑𝑡 𝑑𝑡 𝑑𝑡

Rate constants of rate equation (k) is determined by Arrhenius concept.

𝐸𝐴
k = A 𝑒 −𝑅 𝑇

Where,

A = Pre-exponential Factor

17
𝐸𝐴 = Activation Energy
R = Gas constant

T = Reaction Temperature

Table 2. Yield of Different Combinations of Plastics

Feed Temperature Pyrolysis Type Gas Liquid Char

(°C) Yield Yield Yield
(%) (%) (%)
𝑃𝑃[10] 500 Thermal degradation 17 70 13
𝑃𝐸 [8] 475 Thermal degradation 14 70 16
𝑃𝑃 + 𝑃𝐸 500 Thermal degradation 16 80 4
+ 𝑃𝐸𝑇 [8]
𝑃𝐸𝑇 + 𝑃𝑆 [11] 400 Thermal degradation 15 63 22
𝑃𝑃 + 𝑃𝐸 750 Thermal degradation 46.6 52 1.4
+ 𝑃𝑆 [14]
𝑃𝑆 [14] 580 Thermal degradation 9.9 24.6 65.5
𝐴𝐿𝐿[13] 500 Catalytic degradation 56.9 40.4 3.2
PP+PE+PS [12] 400 FCC 80.3 7.4 12.3

2.9 Merits and Demerits of Fluidized Bed Catalytic Pyrolysis Reactors

There are advantages as well as disadvantages of the selection of fluidized bed catalytic pyrolysis
reactors for the conversion of waste plastic into fuel oil and gas.[13] The advantages of fluidized
bed catalytic pyrolysis reactors are:
• Operated at lower temperatures and lower pressures because of the catalyst.
• Ability to crack longer chain hydrocarbon molecules.
• The capital cost and the maintenance cost of the conversion method is low.
• Volume of the solid waste is significantly low.

18
The disadvantages of fluidized bed catalytic pyrolysis reactors are:
• Catalyst disposal or regeneration should be done as it is coated with carbon.
• The conversion process must be done in the absence of oxygen.
• The conversion temperature is low thereby production of toxic organic compounds.

2.10 Catalyst and Pyrolysis

Plastic waste may contain different kinds of pollutants such as nitrogen, sulphur, and chlorine due
to surface contamination, additives, and heteroatoms containing plastic such as PVC. Therefore,
the quality of liquid oil is compromised by the presence of these pollutants. The thermal pyrolysis
of plastic requires high temperatures (350–500 °C) for degradation. However, a few studies have
reported that temperature demand may increase up to 700 or 900 °C to achieve high quality
products. The low thermal conductivity with endothermic cracking makes the thermal pyrolysis a
high energy-intensive process. In the initial stage of catalytic pyrolysis, the thermal cracking
occurs on the external surface of the catalyst. The internal porous structure of the catalyst then acts
as channels for selective movement and breakdown of larger compounds into smaller ones. [13]

There are three main types of catalysts that are used in pyrolysis of plastic waste. These catalysts
include: FCC, zeolites and silica–alumina catalysts. FCC catalysts are known as silica–alumina
with the binder made up of non-zeolites matrix and zeolites crystal. [13]

The FCC catalysts used in the pyrolysis process are known as spent FCC catalysts, as they come
from refining industries. Moreover, these catalysts are successfully used in pyrolysis process even
though they contain some impurities. 20 wt.% catalyst/polymer ratio was optimum ratio for the
maximum conversion of HDPE plastics wastes into liquid oil. However, increase in
catalyst/polymer ratio increases the gases and char production. The pyrolysis of different types of
plastic waste such as PS, LDPE, HDPE, and PP by using the FCC catalyst reported 80−90% of
liquid oil production. Overall in comparison to other catalysts, FCC catalyst increases the liquid
oil yield. [13]

Silica-alumina catalysts are amorphous catalysts having Lewis acid sites as electron acceptors and
Bronsted acid sites with ionizable hydrogen atoms. The acidity of these catalysts was determined

19
by using mole ratio of SiO2/Al2O3. Acidity of these catalysts affects the production of liquid oil
from pyrolysis of plastics wastes. The higher the acidity, the lower will be the production of liquid
oil. during vapor phase contact, gases production was increased due to further decomposition of
hydrocarbons. In addition, temperature affects the performance of these catalysts. the liquid oil
production can be increased by using silica-alumina catalysts with low acidity and high process
temperature. [13]

Zeolites catalysts are the crystalline alumina-silicates sieves having three-dimensional framework
with cavities and channels, where cations may reside. The ion exchange capabilities and open
pores are the main characteristics of these catalysts. Zeolites catalysts have different ratio of
SiO2/Al2O3 that determine their reactivity and also affect the end products of pyrolysis process.
Zeolites catalysts having high acidity are more active in cracking process, hence increase the
production of light olefins and decrease the heavy fractions. Moreover, the use of these catalysts
increases the gases production and decrease the liquid oil yields. Catalytic pyrolysis of HDPE with
HZSM−5 at 450 °C produced 35 wt.% liquid oil with 65 wt.% gases. Overall zeolites catalysts
increase the volatile hydrocarbon production. Moreover, HZSM−5 has very low rate of
deactivation, thus more suitable for catalyst reuse. All the above-mentioned catalysts have
different characteristics and affect the products of pyrolysis process. [13]

20
3. DESIGN BASIS

The design of our plant is based upon following parameters.

• Capacity: 3.2 ton/day

• Feed and product specification: The feed and product specification are calculated through
mass and energy balance equation presented on CALCULATION AND DESIGN.

The feed and products composition of the plastics were calculated from the mass balance, energy
balance and literature.

3.1 Feed Specification

The feed is assumed to consist the following amount of different plastics. [12]
Table 3. Feed Specification

Feed Weight (%) Flow Rate Density Flow Rate

(kg/h) (kg/m3) (m3/h)
PP 31 62 910 0.068
PE 62 124 935 0.132
PS 7 14 1060 0.0132
Ecat-1 − 333.3 (kg/day) 2400 0.138
𝑁2 − 800 ml/min − −

3.2 Utilities Requirements

The plant requires some utilities for its functioning. The burner should be burned to continuously
supply the energy required for cracking of plastics. So, rice husk at 25 ⁰C and 1 atm is supplied
along with 25% excess air. Among fuels like methane and other gasoline, rice husk was selected
as it is very cheap and has higher calorific value.

21
3.3 Regulation for Safety and Environment

Certain laws and regulations are prescribed by the Nepal government for the protection of
Environment and individual health which need to be taken into account.[18] Some of these are:

- Solid Waste Management Rule 2013

- Protection of Environment Act, 1997[19]
- Industrial Policy, 1992
- National Ambient Air Quality Standard, 2003
- Occupational Health and Safety Guidelines
- National Occupational Safety and Health Policy (Joshi, 2011)

3.4 Design Codes

Various design codes are provided by various companies, among which primary design codes
used were as follows:
1. American Society of Mechanical Engineers (ASME)

1.1 Section VIII (DIV 1.) – Pressure Vessel Code

1.2 Section II – Material Specification

Tubular Exchanger Manufacturers Association (TEMA) – Fired Heater Specification and Heat
exchanger design.

22
4. PROCESS DESCRIPTION

Assumptions for the Mass Balance Calculations:

➢ No HCl in the input plastic.

➢ System is at steady state.
➢ The raw material contains PP, PE and PS plastics only.
➢ Every entered plastic feed gives same fuel output yield and composition.
➢ No leakages from vessels.
➢ The catalyst’s activity will be the same even after the regeneration.
➢ All the pressure reducing valves are adiabatic.
➢ No gas accumulation inside the reactor.
➢ All the used plastic cracked and goes out from the reactor.
➢ Residue is only the spent catalyst and coke.
➢ Catalyst is not carried by the outlet gas stream.
➢ Catalyst is not thermally decomposed.

Assumptions for Energy Balance Calculations:

➢ System is at steady state.

➢ Minimum fluidization will occur.
➢ Every entered plastic feed gives same fuel output yield and composition.
➢ No leakages from vessels.
➢ All the used plastic cracked and goes out from the reactor.
➢ Pressure drop is constant throughout the process.
➢ Heat loss of the furnace to the surroundings is negligible.

23
 Figure 12. General Process Flow Diagram

Above assumptions are simply taken into consideration to make our calculation simpler. As
assumed, the raw material consists of only PP, PE and PS plastics. These plastics are manually
sorted as much as possible. The sorted plastics is then passed to the shredder to reduce the size
using belt conveyor. The product of shredder is then passed through a screen which lets the plastics
pieces which are under the size of 6 mm pass through it and the oversize product is recycled to the
shredder. The sized products are collected to the hopper of capacity of about one ton. The products
are then transported to the reactor by the help of bucket elevator creating an inert environment by
passing nitrogen gas through it at the rate of 200 ml/min. The reactor is enclosed within the burner
which provides the necessary energy as heat for the cracking of plastics into alkane, alkene,
aromatics and other simpler products. The burner is a husk fired burner. Rice husk is used as the
fuel source to fire up the burner. A combination of 25% excess air and rice husk at the flow rate
of about 750 kg/day is enough to fire up the reactor. The reaction temperature is about 400 °C. So,
husk fired burner provides the heat.

The catalyst used is equilibrium catalyst also known as zeolite catalyst. Zeolite is a compound
formed by the mixture of sodium, aluminum, silicon, oxygen and hydrogen. Average chemical
composition of sodium zeolite is reported as Sodium Oxide – 17%, Aluminum Oxide – 28%,
Silicon dioxide – 33% and water – 22%.[20] Molecular formula of zeolite can be generally

24
represented as NaAlSi2O6-H2O. The amount of catalyst used per day is about 350 kg. This amount
is feed to the reactor before the system runs and by the end of the day, the catalyst is nearly dead.
The catalyst can be regenerated and reused adding small amount of fresh catalyst next day. The
catalyst regeneration technique and system are not described in this project report but is possible
for sure.

The residence time of the plastic is about half an hour and the produced gas has residence time of
about two seconds. The reactor should be completely airtight and fluidization is maintained by
purging compressed nitrogen gas at the rate of 600 ml/min. The reaction mostly occurs at the
minimum fluidization. The produced cracked gas is now sent to be condensed to a condenser.
According to literature, the produced cracked product consists of about 80% fuel gas, and 7% fuel
oil and remailing as solid char. The solid char can also be used another field like road construction.
The produced fuel oil and fuel gas consists more 30 compounds in significant quantity. Further
processing like separation could be carried out to obtain pure gas and oils which is not described
in this report as well due to time limitation.

Although the products are not analysed by ourselves, it is taken from various literature. The
product composition can be analysed through Fourier-transform Infrared Spectroscopy (FTIR).
The amount of each compound present could vary slightly but overall composition of fuel oil, fuel
gas and residue remain more or less the same due to the particular quality of catalyst used. The
overall composition was assumed as follows for the simplicity of calculation and design of reactor.

Table 4. Product Specification [12]

Products Composition (%) Flow Rate (kg h-1)

Gas 80.3 160.6
Liquid 7.4 14.8
Residue 12.3 24.6

The overall amount of fuel gas, oil and residue formed was assumed as above and the number and
compounds formed was also assumed by the study of various literatures. The enthalpy of formation
of product was also calculated. The calculations are shown in the appendix section. The overall
enthalpy of reaction was calculated and that amount of enthalpy of reaction is the amount of energy
to be supplied for the reaction to carry out. This amount is then supplied to the system by external
source, i.e., burner, in this plant.

25
Fluidized beds have gained wide usage in the petroleum and chemical processing industries. They
are used for separations, rapid heat and mass transfer operations, and catalytic reactions. A typical
fluidized bed is cylindrical in shape and contains particles through which fluid (gaseous or liquid)
flows. For a fluidized bed reactor, sand can be used as a catalyst. The velocity of the fluid released
to the reactor should be sufficiently high to suspend or fluidize the particles thereby providing a
large surface area for the reaction. Fluidized beds can range in sizes from small scale laboratory
equipment to large industrial systems.

4.1 Fluidization Theory

Fluidization occurs when an upward-flowing gas passing through a porous distributor plate,
imposes a sufficiently high drag force to overcome the gravitational force exerted on the particles.
The drag force is as a result of the frictional force imposed on the particle by the gas; the particle
imposes an equal and opposite drag force on the fluidizing gas. This implies that as a particle
becomes more fluidized, the local gas velocity around the particle due to these drag forces are also
affected. For spherical particles, this effect is minimal, however, the effect of these drag forces is
significant for irregularly shaped particles.

When the particles are fluidized, the bed behaves differently as velocity, solid and gas properties
are varied. There are a number of flow regimes that can result depending on the velocity of the
fluidizing gas. When the flow of the fluidizing gas passing through a bed of particles is increased
continually, some particles may vibrate, but the height of the bed remains the same. This is called
a fixed bed (Figure 13A). Increasing the gas velocity further, a point is reached when the drag force
by the upward flowing gas equals the weight of the particles. The bed void also increases slightly.
This is the onset of fluidization and it is called the minimum fluidization (Figure 13 B). The velocity
at this point is called the minimum fluidizing velocity. Increasing the velocity of the gas beyond
the minimum fluidizing velocity will lead to the formation of bubbles (Figure 13 C). If the velocity
is increased further, the bubbles coalesce and grow in size as they rise. If the ratio of the bed height
to the bed diameter is sufficient, the diameter of the bubbles may be the same as the diameter of
the bed. This is known as slugging (Figure 13 D). At sufficiently high gas flow rate, the velocity
exceeds the terminal velocity (the velocity required to transport particles out of the bed). The upper

26
surface of the bed disappears and a turbulent motion (Figure 13 E) of solid clusters and voids of
gas of various shapes and sizes form in the bed. Further increase of the gas velocity creates an
entrained bed with disperse, lean or dilute phase fluidized bed which results in pneumatic solid
transport (Figure 13 F).[3]

Figure 13. Schematic representation of the different regimes of fluidized bed by Kunni and Levenspiel

27
5. PROCESS FLOW DIAGRAM

One of the primary assets of any plant design is preparation of detailed and simple process flow
diagram. More detailed the process flow diagram, clearer is the way a plant functions and its set
up becomes much easier too. The process flow diagram prepared by us consists of major equipment
like reactor, burner, condenser, shredder, etc. The flow directions of each stream are mentioned
clearly and control valves are provided where necessary. The operational data like temperature,
pressure, mass flow rates are clearly mentioned as well.
For further clarity, P&ID of the process flow diagram should be consulted and mass balance and
energy balance of necessary units are included in the Appendix section. Since the system
comprises of both the solid and fluid handling, the system should be run manually as well as
controlled by Programming Logic Controller (PLC) for solid handling and fluid handling is
controlled by the sensors and transducers.
The primary process flow diagram is given below:

28
Figure 14. Process Flow Diagram of Plastics Pyrolysis Plant

29
6. PIPING AND INSTRUMENTATION DIAGRAM

Piping and Instrumentation diagram is one of the most important parts of any plant design. The detailed design is expressed as much as possible in
a P&ID. The piping and instrumentation diagrams are given below.

Figure 15. Piping and Instrumentation Diagram for Plastic Pyrolysis Diagram

30
Figure 16.Piping and Instrumentation Diagram for Mechanical Process

31
Figure 17. Piping and Instrumentation Diagram for Chemical Process

32
7. CALCULATION AND DESIGN

7.1 Fluidized Bed Reactor [33]

7.1.1 Mass Balance for the Reactor

The materials balance of the fluidized bed reactor will be calculated according to product
composition, degree of cracking catalyst, optimum temperature and pressure inside the reactor.
Material balance is done by following the law of conservation of mass. [21]

Assumptions:

• Steady state
• Catalyst is not thermally decomposed
• Same activity of catalyst after regeneration
• No gas accumulation inside the reactor
• All the used plastics cracked and goes out from reactor
• Residue is only spent catalyst and coke
• Catalyst is not carried out by the gas
• Catalyst is not thermally decomposed

The general mass balance equation is denoted by:

Rate of mass in + Rate of mass generated = Rate of mass out + Rate of mass accumulated + Rate
of mass consumed

By applying overall mass balance

Mass in = Waste plastic feed (200 kg ℎ𝑟 −1 ) + Ecat-1 feed (333.3 kg 𝑑𝑎𝑦 −1 )

Mass generation = Hydrocarbon Mixtures (175.4 kg ℎ𝑟 −1 ) + Solid Residue (24.5 kg ℎ𝑟 −1 )

Mass out = Hydrocarbon Mixtures (175.4 kg ℎ𝑟 −1 )

Mass accumulated = Solid Residue (24.5 kg ℎ𝑟 −1 )

Mass consumed = Waste plastic feed (200 kg ℎ𝑟 −1 )

33
7.1.2 Energy Balance for the Reactor

The energy balance of the catalytic fluidized bed reactor will be evaluated by considering
thermochemical properties of feed and product at different temperature and constant pressure.
Energy balance is done according to conservation of energy. [22]

Assumptions:

• Steady state
• Minimum fluidization occurs
• No leakage from vessels
• All used plastic cracked and goes out from reactor
• Pressure drop is constant
• Heat loss of furnace to surrounding is negligible

The general energy balance equation is given by:

Rate of energy accumulation = Rate of energy entering the system by inflow − Rate of energy
leaving the system by outflow + Rate of heat added to the system + Rate of work done on system

Amount of heat required for the catalytic cracking:

∆𝐻 =∑ (∆𝐻𝑓⁰) (product) − ∑ (∆𝐻𝑓⁰) (reactant)

Enthalpy of Reactant:

∆𝐻𝑓⁰ = m*(∆𝐻𝑓⁰) at 25 ℃ (reactant) + m*ῠ*𝐶𝑝 *∆𝑇 (reactant)

= (−229354.9354 + 138825)/3600

= −102.2722043 KW

Enthalpy of Product:

∆𝐻𝑓⁰ = m*(∆𝐻𝑓⁰) at 25℃ (product) + m*ῠ*𝐶𝑝 *∆𝑇 (product)

= (−105946.936 + 150619.4707)/3600

= 12.40903741 KW

34
Total Enthalpy is given by:

Enthalpy of reaction = Enthalpy of product − Enthalpy of Reactant

∆𝐻 = [12.40903741 − (−102.272)] KW = 114.68 KW.

This amount of energy should be continuously supplied to the reactor to carry out the complete
cracking.

35
Table 5. Enthalpy of Formation of Reactant

Type of Material Mass Flow Rate (kg/h) Enthalpy of Specific Heat Capacity Cp*(T− 298.15) Formation Energy
Formation at 25 °C (KJ/kg/K) [22] of the Material at
(KJ/kg) [22] 400 ℃
PE 124 −1732.26 1.95 731.25 −84.85423333
PP 62 −456.3918177 1.8 675 −19.4850813
PS 14 981.5427 1.2 450 2.06711
Total 200 −1207.109156 4.95 1856.25 −102.2722043

Table 6. Enthalpy of Formation of Products

Type of Material Component [23] Mass Flow Rate Enthalpy Specific Heat Cp*(T− 298.15) Formation
(kg/h) Formation at 25 Capacity Energy of the
℃ (KJ/kg) [22] (KJ/kg/K) Material at 400
℃
C1-C4 METHANE 1.238638884 −4675 3.05 1143.75 −1.214984322
ETHANE 2.146974066 −2823.33 2.63 986.25 −1.095600866
PROPANE 10.01856955 −2360.91 2.55 956.25 −3.909078861
BUTANE 4.791445398 −2150 2.55 956.25 −1.588829985
ETHENE 0.652327085 1867.85 2.24 840 0.490667749
PROPENE 1.523571199 497.61 2.27 851.25 0.570856735
BUTENE 1.306809395 −9.64 2.29 858.75 0.308229146
AROMATICS BENZENE 10.07222121 1062.8 1.72 645 4.778149828
ETHYLBENZENE 31.80829192 282.07 1.9 712.5 8.787659138
O-XYLENE 5.83022332 100.18 1.92 720 1.328286823
2.915208033 163.2 1.88 705 0.703051004
M-XYLENE
P-XYLENE 2.915208033 169.81 1.88 705 0.70840365
TOLUENE 11.64909415 543.58 1.81 678.75 3.955288127

36
 N- 5.83022332 65.83 1.97 738.75 1.303022522
PROPYLBENZENE
N- 8.733992132 −88.05 2.03 761.25 1.633256529
BUTYLBENZENE
ALIPHATIC/ N-PENTANE 3.468188876 −2038.33 2.53 948.75 −1.049685899
ALKANE
N-HEXANE 3.468188876 −1940.93 2.5 937.5 −0.966690212
N-HEPTANE 3.468188876 −1877.8 2.49 933.75 −0.909484363
N-OCTANE 3.468188876 −1831.9 2.48 930 −0.868877652
N-NONANE 3.468188876 −1791.4 2.47 926.25 −0.833473224
N-DECAN 3.468188876 −1756.33 2.47 926.25 −0.799687284
N-UNDECANE 3.468188876 −2097.43 2.27 851.25 −1.200552115
N-DODECANE 3.468188876 −2064.11 2.69 1008.75 −1.016718837
ALIPHATIC/ALKENE 1-PENTENE 3.468188876 −304.2 2.33 873.75 0.548696382
1-HEXENE 3.468188876 −499.4 2.35 881.25 0.367868867
1-HEPTENE 3.468188876 −640.52 2.36 885 0.23552856
1-OCTENE 3.468188876 −725.9 2.37 888.75 0.156887377
1-NONENE 3.468188876 −819.87 2.38 892.5 0.069970711
1-DECENE 3.468188876 −880.71 2.38 892.5 0.011358319
1-UNDECENE 3.468188876 −810 2.39 896.25 0.083092025
1-DODECENE 3.468188876 −996.38 2.39 896.25 −0.09646382
CYCLOALKANE CYCLOHEPTANE 3.695272671 −1207.14 2.15 806.25 −0.411499406
CYCLOOCTANE 3.695272671 −1110.71 2.12 795 −0.324065149
CYCLOHEXANE 3.695272671 −1465.95 2.25 843.75 −0.638666293
CYCLOPENTANE 3.695272671 −1094.28 2.24 840 −0.261009426
CYCLOBUTANE 3.695272671 496.78 2.25 843.75 1.376006632

37
 SOLID RESIDUE 24.6 0.85 318.75 2.178125
175.4001831 12.40903741

7.1.3 Design of Fluidized Bed Reactor

The design of the reactor was carried out by calculating minimum fluidization velocity, minimum fluidized height, terminal velocity,
slugging velocity, minimum fluidized bed void fraction, volume of reactor, distributed plate pressure drop, fixed bed pressure drop,
shell wall thickness and shell head thickness.[3]

Mass of solid in the is given by

Ws = 𝜌 * A * (1 − ε) * h

Ws
h = ρ∗ A ∗ (1− ε)

4∗𝑀 ∗𝑔
h = π∗ ρ∗ (1−𝑠 ε)∗𝐷2

Assumptions:

𝐿
• =3
𝐷

• Turbulent flow

3 0.071
Void fraction at minimum fluidization is given by 𝜀𝑚𝑓 = √ = 0.41
𝜑

38
 ℎ𝑝 ∗(1−𝐸)
Minimum Fluidization Height (hmin) = (1 − ε𝑚𝑓 )
= 1m

𝑔∗(𝜌𝑝 −𝜌𝑓 )∗ε𝑚𝑓 3 ∗𝑑𝑝

Minimum fluidization velocity (𝑢𝑚𝑓 ) = √ = 0.21 ms-1
1.75∗ 𝜌𝑓

𝑔∗(𝜌𝑝 −𝜌𝑓 )∗𝑑𝑝 ∗𝑑𝑝

Terminal velocity (ut) = = 0.49 ms-1
18∗𝜇𝑓

Slugging velocity (ums) = umf + 0.07 * (√𝑔 ∗ 𝐷 ) = 0.42 ms-1

Therefore,

umf < u < ut

Fixed Bed Pressure Drop (∆Pb) = hp * (1 − ε) * (𝜌𝑝 − 𝜌𝑓 ) = 0.089 atm

Distributed plate pressure drop ( ∆Pd) = 0.3* ∆Pb = 0.0267 atm

3
Volume of Reactor (V) = 4 * 𝜋 ∗ 𝐷3 = 1.71 m3

By using cylindrical shell

𝑃∗𝐷
Wall Thickness (tw) = 2∗𝑆∗𝐸 − 1.2∗𝑃 + c = 5.79 + 4.76 = 10.55 mm

𝜎
s = 𝑓 = 52400000 Nm-2

2∗ ∆Pd 0.5
Gas velocity through orifice (uo) = CD *( ) = 26.07 ms-1
𝜌𝑔

Diameter of orifice (do) = 3 mm

Diameter of nozzle (dn) = 10 mm

Nozzle height (hi) = 72.54 mm

𝑑𝑛 − 𝑑𝑜
Minimum nozzle height (lm) = = 36.27 mm
0.193

39
 3∗(3+𝑢)∗𝑃𝑝𝑙𝑎𝑡𝑒 ∗𝑟 2
tp = √ + C = 11 + 4.7 = 15.76 mm
8∗𝜎𝑚

𝐹𝑜𝑟𝑐𝑒(𝐹)
Pressure in the plate (𝑃𝑝𝑙𝑎𝑡𝑒 ) = 𝐴𝑟𝑒𝑎(𝐴)

Force (F) = (200+333.3) * 9.81 = 5226.63 N

Area(A) = 0.196 m2

𝑃∗ 𝑑
Thickness of nozzle (Tn) = (2∗𝑠∗𝐸) − 𝑛(1.2∗𝑃) + C = 0.0387 + 1.587 = 1.62 mm

Taking Head Type as Standard Dished type

Shell Head Thickness (T) = 25 mm (Taken from reference)

7.2 Husked Fired Furnace Design

The Fired heater or simply burner is so designed to provide the necessary energy to the reactor to
proceed the cracking process without any interruption. The ignition source is jute sack, coal and
diesel. This combination is used to ignite the burner n the initial stage. As soon as the husk is set
on fire by the coal and diesel, the supply is cut off and only husk is used to fire up the system.
For the oxidation is sufficiently supplied using forced draft fan.

7.2.1 Energy Requirement Calculation and Design [24]

The energy supplied by the burner should be sufficient for the reactor to run. From the energy
balance calculation of reactor, heat required is given by:

Q = 114.68 KW

The fuel value of husk is provided as:

Fuel value (f) = 12600 KJ kg-1

Now, Heat liberated by fuel is taken as:

40
 𝑄 114.68
Qf = 𝜂 = = 163.8 KW
70%

Similarly, mass of fuel required is given as:

𝑄𝑓 163.8 𝐾𝑊
Mfuel = = 𝐾𝐽 = 0.013 kgs-1
𝑓 12600
𝐾𝑔

For 16 hours, estimated as per day:

𝑀𝑓𝑢𝑒𝑙 = 748.8 Kg day-1

Air to fuel ratio (AFR) is the amount of air required for a unit of fuel to oxidize completely. For
rice husk,

𝐾𝑔 𝑎𝑖𝑟
AFR = 4.7 𝐾𝑔 ℎ𝑢𝑠𝑘

𝑀𝑎𝑖𝑟 = AFR * 𝑀𝑓𝑢𝑒𝑙 = 3519.36 Kg air day-1

With 25% excess air,

Mass of total air required (𝑀𝑇𝑎𝑖𝑟 ) = 1.25 *3519.36 = 4400 kg air day-1

Heat provided by the air is given as:

Qair = 𝑀𝑇𝑎𝑖𝑟 *(Cp)air * (Tg – Tr) = 1.39 KW

Heat radiated through the wall, Qwall = 2% * Qf = 3.3 KW

Heat of exhaust gas:

Qh = Mfuel * (1 + G) * Cpavg * (Tg – 520) = 95.32 KW

For the assumed formation of exhaust gas as 71% of nitrogen gas, 17% of water and 12% of
Carbon Dioxide:

𝐾𝐽
Cpavg = ∑𝑥𝑖 . 𝐶𝑝𝑖 = 𝑥1 ∗ 𝐶𝑝1 + 𝑥2 ∗ 𝐶𝑝2 + 𝑥3 ∗ 𝐶𝑝3 = 1.87 𝐾𝑔 𝐾

41
Finally, Net heat liberated (Ql) is given as:

Ql = Qf – Qw – Qh + Qair = 66.57 KW

7.2.2 Stack Design [25]

1 1
𝑃𝑑 = 0.35*𝐿𝑠 *P*(𝑇 – 𝑇 )
𝑎 𝑔𝑎

Pd = 12.7 mm H2O; P = 1013.25 mbar

𝐿𝑠 = 16 m

Length of Stack is 16 m.

7.3 Condenser Design Calculation [25]

The pyrolyzed vapor coming out of the reactor should be condensed to separate the fuel oil and
fuel gas in general to room temperature. So, the total amount of vapor coming out as product
from the reactor is the mixture of gas and fuel liquid. Therefore,

Vapor from reactor = Gas + Liquid

175.4 kg ℎ−1 = 160.6 kg ℎ−1 + 14.8 kg ℎ−1

Assumptions

• Hydrocarbon mixture is considered as the single component hydrocarbon vapor of

𝐾𝐽
specific heat capacity 0.5 𝐾𝑔 𝐾
𝐾𝐽
• Specific heat capacity of liquid fuel is 1.75 𝐾𝑔 𝐾

• Outlet Temperature from Reactor is 390 ℃

• Final Temperature of fuel oil and fuel gas is 35 ℃
𝐾𝐽
• Latent heat of vaporization of hydrocarbon mixture is 263
𝐾𝑔

42
 • Initial boiling point of fuel oil is 35 ℃
• Final boiling points of fuel oil is 384 ℃
𝐾𝐽
• Heat capacity of water is 4.18 𝐾𝑔 𝐾

• Colling water inlet temperature is 25 ℃

• Colling water outlet temperature is 35 ℃
• Length of tube (l1) = 1.83 m
• Outer diameter of tube (d1o) = 16 mm
• Inner diameter of tube (d1i) = 12 mm
𝑊
• Overall trail heat-transfer co-efficient (Ua) = 150 𝑚2 𝐾

Now,

Energy by fuel gas = 𝑚𝑔 * (𝑐𝑝 )𝑔𝑎𝑠 * ∆𝑇 = 160.6*0.5*(390-35) = 7.92 KW

Energy by fuel oil = 𝑚𝑙 * (𝑐𝑝 )𝑜𝑖𝑙 * ∆𝑇 + 𝑚𝑙 * (𝑐𝑝 )𝑜𝑖𝑙 * ∆𝑇 + 𝑚𝑙 * 𝐿𝑓𝑢𝑒𝑙

= 14.8*0.5*(390 − 384) + 14.8*1.78*(384 − 35) + 14.8*263 = 3.65 KW

Heat load = Energy by fuel gas + Energy of fuel oil = 3.65 + 7.92 = 11.57 KW

𝐻𝑒𝑎𝑡 𝑙𝑜𝑎𝑑 11.57 𝑘𝑔

Mass flow rate of cooling water required = 𝐶 = = 0.27 𝑠𝑒𝑐
𝑝 𝑜𝑓 𝑤𝑎𝑡𝑒𝑟 ∗∆𝑇 4.18∗(35−25)

For one shell and two pass-condenser,

390 − 35
R= = 35.5
35 − 25

35 − 25
S = 390 − 25 = 0.027

(390 − 35)−(35 − 25)

∆𝑇𝑙𝑚 = 390 − 35 = 95.90 ℃
ln ( )
35 − 25

√𝑅 2 +1 ln[(1 − S)/(1 − RS)]

Ft = * = 0.96
𝑅−1 2 − 𝑆[𝑅 + 1 − √𝑅2 + 1 ]
ln[ ]
2 + 𝑆[𝑅 + 1 + √𝑅2 + 1]

Corrected log mean temperature ∆𝑇 = Ft * ∆𝑇𝑙𝑚 = 0.96 *95.90 = 92 ℃

43
Area of one tube = 𝜋 * d1o * l = 0.092 m2

𝐻𝑒𝑎𝑡 𝑙𝑜𝑎𝑑 𝑖𝑛 𝐽𝑜𝑢𝑙𝑒 11.56 ∗ 1000

Provisional Area =𝐴𝑠𝑠𝑢𝑚𝑒𝑑 𝑈∗𝑐𝑜𝑟𝑒𝑐𝑡𝑒𝑑 log 𝑚𝑒𝑎𝑛 𝑇𝑒𝑚𝑝 = = 0.84 m2
150 ∗ 92

𝑃𝑟𝑜𝑣𝑖𝑠𝑖𝑜𝑛𝑎𝑙 𝐴𝑟𝑒𝑎 0.84

Number of tubes (N) = = 0.092 = 10
𝐴𝑟𝑒𝑎 𝑜𝑓 𝑎 𝑡𝑢𝑏𝑒

7.3.1 Tube Side Heat Transfer Coefficient

35 + 25
∆𝑇𝑚 = = 30 °C
2

𝜋 ∗ 𝑑𝑖 2 𝜋 ∗ 122
Area of tube (At) = = = 113.1 mm2
4 4

Number of tubes (N) = 10

𝑁
Tube per pass = =5
2

Total flow area = 5 * 113.1 * 10-6 m2 = 0.00057 m2

𝑘𝑔
0.27 𝑘𝑔
Mass velocity = 0.00057𝑠 𝑚2 = 437.68 𝑚2 .𝑠

𝜌water = 995.6 kg/m3

kg
473.68
m2 𝑠
Velocity (v) = kg = 0.47 m/s
995.6 3
m

hi .𝑑1𝑖 𝜇 0.14
= jn. Re. Pr1.33.(𝜇𝑓)
kf

𝜌water∗v∗𝑑1𝑖 995.6 ∗ 0.47 ∗ 12 ∗ 10−3

Re= = = 7018.98
𝜇𝑤 0.8 ∗ 10−3

(𝐶𝑝)𝑤𝑎𝑡𝑒𝑟 ∗ 𝜇𝑤
Pr = = 5.7
kf

𝐿1 1.83
= 12 ∗ 10−3 = 152.5
d1i

Jn = 3.8 * 10-3 (from graph)

44
hi .𝑑1𝑖
= 3.8 * 10-3 * 1120.05*5.70.33
kf

hi * 12 * 10-3 = 49.86 * 0.59

𝑊
hi = 2451.45 𝑚2 ℃

𝑊
Heat Transfer Coefficient for the tube side is calculated to be 2451.45 𝑚2 ℃

7.3.2 Shell Side Coefficient

For triangular pitch configuration of tubes,

Pitch (Pt) = 1.25 * d1o = 20 mm

𝑛 𝑁
Bundle diameter (Db) = d1o * √𝐾 = 85.27 mm

Use a split ring floating head type,

Bundle diameter clearance = 50 mm (obtained from the graph)

Shell Inside Diameter (Ds) = 50 + 85.27 = 135.27 mm

𝐷𝑠
Baffle Spacing (𝑙𝐵 ) = = 27.05 mm
5

(𝑝𝑡 − 𝑑𝑜 )𝐷𝑠 𝑙𝐵
Area of shell = 𝜌𝑡

(20 − 16) ∗ 0.1352 ∗ 0.027

= 20

= 0.0007 m2

𝑘𝑔
175.4 1 ℎ𝑟
ℎ𝑟
𝐺𝑠 = ∗ 3600𝑠
0.0007 𝑚2

𝐾𝑔
= 69.6 𝑚2 𝑠

45
 1.1
Equivalent Diameter (𝑑𝑒 ) = 1.6 (202 − 0.917 ∗ 162 ) = 1.36 𝑚𝑚

390+35
𝑇𝑠ℎ𝑒𝑙𝑙 = = 212.5 ℃
2

𝑘𝑔 −3
𝐺𝑠 𝑑𝑒 69.6 𝑚2 . 𝑠 ∗ 11.36 ∗ 10
𝑅𝑒 = = = 11295.08
𝜇 7 ∗ 10−5

(𝐶𝑝 )𝑔𝑎𝑠 ∗ 𝜇 0.5 ∗ 1000 ∗ 7 ∗ 10−5

𝑃𝑟 = = = 0.25
(𝑘)𝑔𝑎𝑠 0.1385

Jn= 2.8*10-3

The Shell Side Heat Transfer Coefficient is given as:

2.8∗10−3 ∗ 0.1385 ∗ 11295.08 ∗ 0.250.33 𝑊

hs = = 261.45 𝑚2 ℃
11.36 ∗ 10−3

7.3.3 Overall Calculated Heat Transfer Coefficient

𝑑
1 1 1 𝑑0 ln ( 0 ) 𝑑 1 1
𝑑𝑖
=ℎ + + * + 𝑑0 * (ℎ + ℎ )
𝑈0 0 ℎ0𝑑 2 𝑘 𝑖 𝑖 𝑖𝑑

(Refer to calculations and assumptions and constant value for value of each term.

𝑊
𝑈0 = 202 𝑚2 ℃

202 − 150
Error = * 100 = 25%, which is within acceptable range.
150

7.3.4 Pressure Drop Calculation

From graph with the value of Re,

jf is taken as 2.8*10-3
𝐿1 𝜌𝑤 ∗𝑢𝑡 2
∆𝑃𝑡 = Np * [8 * jf * (𝑑1 ) + 2.5] * = 2.16 kPa
𝑖 2

𝑠 𝐺
𝑢𝑠 = (𝜌)𝑣𝑎𝑝𝑜𝑟 = 8.03 ms-1

46
From Re and 35% baffle cut,
jf is taken as 3 *10-3 from graph.
𝐷 𝐿 𝜌𝑣𝑎𝑝𝑜𝑟 ∗𝑢𝑠 2
∆𝑃𝑠 = 8 * jf * (𝑑 𝑠 )* (𝑙 ) * = 7.2 kPa
𝑒 𝑏 2

The pressure drop in the shell side is calculated to be 7.2 kPa.

7.4 Pipe Diameter Calculation [26]

Rules of Thumb:

- Velocity for gases: 100 ft/s (dry), 60 ft/s (wet)

- Velocity for steam: 100 ft/s (< 8 bar), 150 ft/s (> 8bar)

𝑣 = velocity of fluid

𝑉𝑜𝑙𝑢𝑚𝑒𝑡𝑟𝑖𝑐 𝐹𝑙𝑜𝑤 𝑅𝑎𝑡𝑒 𝑉

Area (a) = =𝑣
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦

We have, mass flow rate of fluid coming out of system,

𝐾𝑔
𝑚 = 175.4 ℎ

𝐾𝑔
Density of fluid flowing out of reactor = 5 𝑚3

𝑚3
Volumetric Flow rate (V) = 175.4/5 = 35.08 ℎ

𝑚3
35.08
Now, Area required for flow (a) = 𝑓𝑡
ℎ
= 0.00053 m2
60
𝑠

4∗𝑎
Thus, Diameter (d) = √ = 0.026 m = 26 mm
𝜋

Similarly, calculation for each stream of fluid flow was calculated.

47
7.5 Design Calculation of Liquid Vapor Separator [25]

𝜌𝑙 −𝜌𝑣 𝑚
Settling velocity (u1t) = 0.07 * √ = 0.64
𝜌𝑣 𝑠

Assuming the holdup volume as 10 minutes,

𝑚3
Vapor flow rate on liquid vapor separator (Q1) = 0.005 𝑠

Volume (V1) = Q1 * 10*60 = 3.37 m3

4∗𝑣
Minimum vessel diameter (Dv) = √𝜋∗𝑢1 = 2.58 m
𝑠

𝜋
Vessel area (A) = 4 * (Dv)2 = 5.26 m2

𝑉1
Liquid depth (h1) = = 0 .64 m
𝐴

For cylindrical shell thickness,

𝑃∗𝐷 404000 ∗ 4
tw = + c = (2 + 1.58 = 25 + 1.58 = 26.58 mm
2∗𝑆∗𝐸−1.2∗𝑃 ∗ 52500000 ∗ 0.6) − (1.2 ∗ 4040000)

For head,

Using standard dished head

Wall thickness = 25 mm (taking from reference)

7.6 Design Calculation of Cyclone Separator [27]

Using standard cyclone dimension,

Diameter (D) = 1 m

Width (W) = 0.25 m

Height (H) = 0.5 m

Length of body (Lb) = 2 m

Length of cone (Lc) = 2 m

48
 𝑘𝑔
Density of Particle (𝜌𝑝 ) = 968.33 𝑚3

𝑘𝑔
Density of Gas (𝜌𝑔 ) = 8.66 𝑚3

𝑘𝑔
Dynamic Viscosity (𝜇) = 0.000007 = 7 * 10−5 𝑚.𝑠

Cyclone Lapple Factor (𝛼) = 9.29

Diameter of Particle (Dp) = 0.0001275 m

𝑘𝑔 𝑚3 1 ℎ𝑟 𝑚3
Volumetric Flow Rate (Q2) = 175.4 ℎ𝑟 * 8.66𝑘𝑔 * 3600 𝑠𝑒𝑐 = 0.005 𝑠

Using rule of thumb,

𝑓𝑡 𝑚
Velocity of gas (νi) = 60 𝑠𝑒𝑐 = 18.28 𝑠

Number of turns inside the device,

1 𝐿𝑐
N1 = 𝐻 *(Lb + )=8
2

Cut point diameter is the diameter of cyclone when it functions at 50% efficiency. So, cut point
Diameter is given as:

(9∗𝜇∗𝑊)
Dpc = 2√(2𝜋∗𝑁1∗𝑣 ∗(𝜌 = 13.36 𝜇𝑚
1 𝑝−𝜌 𝑔)

𝑝𝑎𝑡ℎ 𝑙𝑒𝑛𝑔𝑡ℎ 𝜋∗𝐷∗𝑁1 𝜋∗1∗8

Gas residence time (t) = = = = 1.37 s
𝑠𝑝𝑒𝑒𝑑 νi 18.28

𝑊 0.25 𝑚
Particle drift velocity = = 1.37 = 0.18
𝑡 𝑠

Terminal drift transverse velocity,

(𝜌𝑝 − 𝜌𝑔 )∗ 𝑑𝑝2 ∗𝑣𝑖 2

Vt = = 8.27 ms-1
9∗𝜇∗𝐷

𝛼∗𝜌∗𝑣𝑖
Pressure drop (P) = * 𝑣𝑖 = 13.4 kPa
2

Power requirement,

Wf = Q * P = 0.005*13441.75 = 68 W
1
Collection efficiency = 𝑑 = 70%
1+( 𝑐 )2
𝑑𝑝

49
7.7 Design Calculation of Electrostatic Precipitators [25]

Wire potential = 20 KV
For hydrocarbon vapor following parameters are taken from reference
𝑞∗ 𝐸𝑝
Particle migration velocity (w) = 6𝜋∗𝜇∗𝑟 = 0.25 fts-1
𝐴
−𝑤∗( )
Separation efficiency (ἠ) = 1 − 𝑒 𝑄 = 95%

Specific collection Area (SCA) = 39.5 s meter-1

Aspect Ratio (AR) = 1.33

50
8. EQUIPMENT LISTS

Table 7. Equipment List

CHEMICAL PROCESS EQUIPMENT LIST

FBR PYROLYSIS CHECKED BY:
CLIENT: DATE:
LOCATION:
S. ITE EQUIPME QT SERVICE SPEC. AND SIZE PART MATERI OPERATION DESIGN REMAR
No M NT NAME Y AL KS
. NO. TEM PRESSU TEM PRESSU
P RE P RE
(°C) (BAR) (°C) (BAR)
1 R- FLUIDIZE 1 FLUIDIZATIO TYPE: VERTICAL SHEL S/S 304 400 1 520 2
101 D BED N (STANDARD DISH L
REACTOR HEAD)
CAP:1170 L
DIM: 0.9 M I.D
2.95(T.L-T.L)
2 F- FURNACE 1 PYROLYSIS TYPE: SHEL CARBON 400 1 520 2
101 CYLINDRICAL(VERTI L STEEL
CAL)
3 E- CONDENS 1 CONDENSATI TYPE: HORIZONTAL CARBON 400 1 510 2
101 ER ON (STANDARD DISH) SHEL STEEL
SHELL AND TUBE L
4 V- GAS 1 PHASE TYPE: VERTICAL SHEL S/S 304 35 1 50 2
501 LIQUID SEPERATOR (STANDARD DISH L
SEPERAT TYPE HEAD) DIM:
OR 2.58M I. D
ABBREVIATIONS
R-101: Fluidized Bed Reactor V-101: Gas-Liquid Phase Separator
F-101: Furnace E-101: Condenser
SS: Stainless Steel

51
 9. INSTRUMENT LIST [28]

Table 8. Instrument List

JOB: FBR VIA PYROLYSIS INSTRUMENT SCHEDULE DATE:
OPERATING CONDITIONS
PRESS (atm) TEMP (OC) FLOW RATE (m3/h) MO VI (2) CON CO
FLUID RFQ LINE (4)
TAG NO. SERVI L S ∆ L (3) RANGE N. NT.
(1) DEN INSTRUME NO./ MATERIAL NUM P&ID REFERE
CE NO MA NO MA NO MA MIN WG C. P O SIG. OF SET SIZE AC
(STATE) (kg/m3 NT MAK BODY/ELEMENT BER NCES
R. X. R. X. R. X. . T C C. POINT (INC TIO
) ER
(gm) p H) N
Nickel-
Thermocoupl (-)200-
1 TG-101 R-101 HC(G) 1 2 390 500 3 1 8.63 L DO 1/4 Chromium/Nickel- - PID-1
1.72 e(K-type) 1250
Alumel
Nickel-
Thermocoupl (-)200-
2 TG-102 E-101 W(L) 40 25 30 0.97 1 0.9 997 18 L DO 1/4 Chromium/Nickel- - PID-1
e(K-type) 1250
Alumel
Nickel-
FUEL(L/ Thermocoupl (-)200-
3 TG-103 E-101 1 2 35 50 1.72 3 1 8.63 L DO 1/4 Chromium/Nickel- - PID-1
G) e(K-type) 1250
Alumel
Nickel-
1.01 Thermocoupl (-)200-
4 TG-104 E-101 W(L) 2 35 50 0.97 1 0.9 995 18 L DO 1/4 Chromium/Nickel- - PID-1
23 e(K-type) 1250
Alumel
5 TIC-101 R-101 D DO PID-1
Sensor
6 TY-101 E-101 (Piezoelectric L AO 1/4 Nanocomposite PID-1
)
7 TIC-103 E-101 D DO PID-1
Nickel-
Thermocoupl (-)200-
8 TT-101 R-101 HC(G) L DO 1/4 Chromium/Nickel- - PID-1
e(K-type) 1250
Alumel
Nickel-
Thermocoupl (-)200-
9 TT-102 E-101 W(G) L DO 1/4 Chromium/Nickel- - PID-1
e(K-type) 1250
Alumel
0.00 0.000 0.00
10 FI-101 R-101 NG(G) 1.7 2 77 90 0.874 14 Orifice meter L AO 0-450 1/4 S/S-316 - PID-1
015 5 01
Series TFP-
11 FT-101 R-103 L DO PPS Body - PID-1
GI
Flow
12 FIC-101 R-101 Indicator D DO - PID-1
Controller
Flow
13 FY-101 R-101 L AO PID-1
transducer
0.00 0.000 0.00
14 FI-102 R-101 NG(G) 1.7 2 77 90 0.874 14 Orifice meter L AO 0-450 1/4 S/S-316 - PID-1
02 5 01
Series TFP-
15 FT-102 R-101 L DO PPS Body - PID-1
GI
Flow
16 FIC-102 R-101 Indicator D DO - PID-1
Controller
Flow
17 FY-102 R-101 L AO PID-1
transducer
29.9
18 FI-103 F-101 NG(G) 1 2 25 40 245 300 200 0.874 Orifice meter L AO 0-450 1/4 S/S-316 - PID-1
6
Series TFP-
19 FT-103 F-101 L DO PPS Body - PID-1
GI
Flow
20 FIC-103 F-101 Indicator D DO - PID-1
Controller

52
 Flow
21 FY-103 F-101 L AO PID-1
transducer
Series TFP-
22 FT-101 F-101 FUEL(S) 1 2 25 40 0.48 1 0.4 96 L DO PPS Body - PID-1
GI
Flow
FCV-
23 FIC-101 Indicator D DO - PID-1
101
Controller
FCV- Flow
24 FY-101 L AO PID-1
101 transducer
25
NOR: NORMAL
MAX: MAXIMUM
MIN: MINIMUM

26
(1) Fluid state (2) Location (3) Signal Accessories
L: Liquid L: Local AO: Analog Output NG: Natural Gas TFP-GI: Gas Turbine Flow Meter CS: Carbon steel(2.1% C)
G: Gas D:DCS DO: Digital Output SS: Stainless steel R-101: Fluidized Bed Reactor V-101: Phase Separator FCV: Flow Control Valve

S: Solid PPS: Polyphenylene Sulfide E-101: Condenser CS: Carbon steel(2.1% C)

53
10. SPECIFICATION SHEETS

10.1 Specification Sheet for Fluidized Bed Reactor

Table 9. Specification Table for Pyrolysis Reactor

PROJECT NAME: PYROLYSIS FBR SPECIFICATION SHEET

PROJECT NUMBER: SHEET
NO.:
REV DATE: BY APVD REV DATE BY APVD

PLANT PLASTIC PYROLYSIS ITEM No's.

LOCATION
SERVICE DESULFURIZATION OF NG
SIZE 1.71 m3 Dia. 0.9 m
CAPACITY 3.5 ton
STANDARD REFERENCE DESIGN DATA
DRAWINGS
CODE ASME SEC. VIII STAMP
DIV. I REQ.
DESIGN PRES. 2 atm DESIGN 520 °C
TEMP.
OPERATING 1 atm OPER. 400 °C
PRES. TEMP.
OPERATING 200 kg/h
FLOW RATE
FACTOR OF SAFETY 3
DENSITY 1700 kg/m3
COMPOSITION PE (62%), PP (31%), PS (7%)
(%)
VOID FRACTION 0.45
MINIMUM 0.21 m/s
FLUIDIZED
VELOCITY
TERMINAL 0.49 m/s
VELOCITY
PRESSURE DROP 0.089 atm
ON BED
SLUDGING 0.42 m/s
VELOCITY
CORROSION 4.76 mm
ALL'W.
ALLOWABLE 20*106 N/m2
STRESS
MASS OF 400 Kg
CATALYST
WIND LOAD. SEISMIC
FACTOR
COMMENTS TESTS
X-RAY
ITEM THICKNESS MAT. TYPE COMMENTS
SHELL 35.25 mm S/S 304 CYLIDRICAL
HEAD 25.85 mm S/S 304 STANDARD DISHED

54
 WALL 5.79 mm S/S 304 CYLINDRICAL
INSULATION
CATALYST 15.76 mm INERT PELLETS
SUPPORT
NOZZLE SCHEDULE
TAG NO. SERVICE NO. SIZE RATING FACING PROJECTION
N-1 INLET 1 12 inches 400 Narrow
faced
N-2 OUTLET 2 2.5 inches 400 Narrow
faced
N-3 CATALYST 3 12 inches 400 Narrow
DISCHARGE faced
N-4 INLET FOR N2 4 2.5 inches 400 Narrow
faced
REMARKS
Catalysts are randomly packed.

55
10.2 Specification Sheet for Heat Exchanger

Table 10. Specification Sheet for Heat Exchanger

HEAT EXCHANGER SPECIFICATION SHEET

Company: Kathmandu University
Tag No.: E102 Design Code: TEMA
P&ID No.: E102
Service of Unit: Condensation of Pyrolysis Gas
FLUID PROPERTIES DATA
Fluid Allocation Shell Side Tube Side
Fluid Name Hydrocarbon Vapor Water
Fluid Quantity, Total kg/h 175.4 995.6
Vapor (In/Out) kg/h 175.4 160.6 N/A N/A
Liquid (In/Out) kg/h N/A 14.8 995.6 N/A
Non-Condensable kg/h 14.8
Temperature (In/Out) °C 390 35 25 35
3
Density kg/m 8.66 997 995.6
-5 -5 -4
Viscosity kg/m/s 7*10 7*10 8*10 7*10-3
Molecular Weight 18
Specific Heat Capacity kJ/kg/K 0.5 - 4.2 4.2
Thermal Conductivity W/m/°C 0.1385 - 0.59 -
Mass Velocity kg/m2/s 69.6 473.68
Pressure Drop kPa 7.2 2.16
Fouling Resistance (minimum) W/m2/°C 5000 4000
2
Overall Heat Transfer Coefficient 150 W/m /°C
CONSTRUCTION DATA SKETCH
Heat Transfer Area (m2) 0.84
Shell Side Tube Side
Design Pressure atm 2 2
Design Temp. °C 510 50
Number of Passes per 1 2
Shell
Material CARBON STEEL CARBON STEEL
Inlet Nozzle (ID/NO) 1 0.5
inches
Outlet Nozzle (ID/NO) 1 0.5
inches
Tube No. 10 OD: 16mm Thickness: 4mm Length: 1.83m Pitch: 20mm
Tube Type: Bare Tube Pattern: Triangular
Shell Outer Diameter: 135.27mm Shell Thickness: 25mm
Head: Standard Thickness: 25mm Insulation: Not required
Baffle: Crossing Cut(%d) 35% Spacing: 27.5mm Type: Single

56
10.3 Specification Sheet for Husk Fired Furnace

Table 11. Specification Sheet for Husk Fired Furnace

PROCESS DATA SHEET FOR HUSK FIRED FURNANCE

1 JOB NUMBER REQUIRED
2 MANUFACTURER REFERENCE
3 TYPE OF FURNANCE: CYLINDRICAL ITEM
4 TOTAL HEATER ABSORBED DUTY
5 PROCESS DESIGN CONDITION
6 SERVICE HEAT THE FBR IN THE ABSENSE OF AIR
7 INPUT TO FBR PE, PP, PS MIXTURE
8 FLOWRATE, KG/HR 200
9 ALLOWABLE PRESSURE DROP
10 HEAT DUTY, KW 114.68
11 AVERAGE RADIATION SECTION DUTY
12 AVERAGE CONVECTION SECTION DUTY
13 FOULING FACTOR
14 RADIATION EXCHANGE FACTOR 0.25
15 RELATIVE ABSORPTION EFFECTIVENESS FACTOR 0.5
16 INLET CONDITIONS
17 MINIMUM NORMAL MAXIMUM STANDARD
18 TEMPERATURE, K 298 328 328 REFERENCE DRAWING
19 PRESSURE, ATM 1 1 4
20 FLOWRATE, 200 280 280
KG/HR
21 AVG MOLECULAR 58.07
WEIGHT,
REPEATED UINT (GRAM
/GRAM MOl)
22 DENSITY, KG/M3 968.33
23 AFR 4.7
24 N2 768

FLOWRATE(L/DAY)
25 COMPOSITION, WT% PP (31)
PE (62)
PS (7)

26 OUTLET CONDITIONS
27 MINIMUM NORMAL MAXIMUM
28 TEMPERATURE, K 663 862 862
29 PRESSURE, ATM 1 1 4
30 FLOWRATE, 175.4 228.02 228.02
KG/HR
31 MOLECULAR WEIGHT,
KG/KG-MOL
32 DENSITY, KG/M3 650
33 VISCOSITY, CP
34 SPECIFIC HEAT,
KJ/KG.K
35 COMPOSITION, % GAS (80.3%)
LIQUID (7.4%)
CHAR (12.3%)

36 COMBUSTION DESIGN
CONDITION

57
37 TYPE OF FUEL HUSK
38 EXCESS AIR, % 25
39 FLOWRATE, KG/DAY HUSK 748.8
AIR 4400
40 INLET TEMPERATURE, K 298.15
41 MOLECULAR WEIGHT, G/G-MOL 1939
42 NET CALORIFIC VALUE, KJ/KG 12600
43 SPECIFIC HEAT, KJ/KG/K
44 PERCENT HEAT LOSS IN COMBUSTION 2
45 FLUE GAS TEMPERATURE LEAVING, K 973.15
46 STACK CONDITION
47 DRAFT TYPE NATURAL
48 DRAFT, MM H2O 12.7
49 AMBIENT TEMPERATURE, K 298.15
50 AMBIENT PRESSURE, MILIBAR 1013.24
51 FLUE GAS LEAVING STACK, K 873.15
52 HEIGHT OF STACK, M 16
53 FURNANCE SPECIFICATION
54 VESSEL SHELL: CARBON STEEL SA516-70

55 REFRACTORY TYPE INSULATING FIRE BRICKS

56 DESIGN CODE ASME C155-97

57 QUALITY C-26
58 THERMAL CONDUCTIVITY, W/m/K 0.35 (1200OC)
59 THICKNESS, mm 63.5
60 CALCULATED HEAT DUTY IN DIFFERENT SECTION, KW
61 HEAT LIBERATED BY FUEL 163.8
62 INLET HEAT BY AIR 1.39
63 HEAT ABSORBED BY WALL 3.3
64 HEAT BY EXHAUST GAS 95.32
65 NET HEAT LIBERATED 66.57

58
10.4 Specification Sheet of Gas-Liquid Separator

Table 12. Gas-Vapor Separation Unit Specification Sheet

Gas-Liquid Separator Specification Sheet

1 COMPANY NAME PROJECT NAME
2 TAG NO.: V-101 PROJECT NUMBER DATE:

3 PLANT NAME Plastic Pyrolysis Item Numbers: 01

Plant
4 Location
5 SERVICE PHASE
SEPARATOR
6 SIZE Dia. 2.58 m Height 6m
7 CAPACITY 4381 L
8 STANDARD REFERENCE DRAWINGS DESIGN DATA
9 CODE ASME SEC. STAMP REQ.
VIII DIV. I
10 DESIGN 4 ATM DESIGN 455 K
PRESSURE TEMPERATURE
11 OPERATING 1 ATM OPERATING 304 K
PRESSURE TEMPERATURE
12 OPERATING 175.4 Kg/h
FLOW RATE
13 DENSITY VAPOR LIQUID
14 (Kg/m3) 8.66 740
15 INLET MASS 175.4
FLOW RATE
(Kg/h)
16 OUTLET LIQUID VAPOR
17 MASS FLOW Fuel oil Fuel Gas (140.85)
RATE (Kg/h) (12.98)
18 CORROSION Negligible
ALLOWANCE
19 ALLOWABLE 52500 kPa
STRESS
20 WIND LOAD SAFETY 4
FACTOR
21 ITEM THICKNESS MATERIAL COMMENTS
TYPE
22 SHELL 26.58 mm S/S 304 CYLINDRICAL
23 HEAD 25 mm S/S 304 STANDARD
DISHED HEAD

24
25 MESH PAD 400 mm MATERIAL S/S 304
26 WIRE TYPE FLAT
27 WIRE SIZE 0.1*0.4
28 POROSITY 0.981

59
29 NOZZLE SCHEDULE
30 TAG NUMBER SERVICE NUMBER SIZE COMMENT
31 N-1 INLET 1 2 INCHES
32 N-2 FUEL OIL 1 2 INCHES
OUTLET
33 N-3 FUEL GAS 1 3 INCHES
DISCHARGE

60
10.5 Specification Sheet for Glove Valve

Table 13. Glove Valve Specification Sheet

GLOBE VALVE SPECIFICATION SHEET DATE:

REF NO:
ITEM GLOBE VALVE
FORM NO.
SERVICE FLOW OF NG
SPECIFICATIONS AND DATA SHEET
S.N.
1. LINE SIZE 0.25’’
2. VALVE SIZE 0.25’’
3. END CONNECTION FLANGED HAVING CLASS 400
4. MATERIAL GROUP 2
5. BODY MATERIAL 18 Cr-8 Ni
6. TYPE OF BODY AND BONNET ASTM A351 CF8 CAST STAINLESS STEEL
7. FLOWING MEDIUM NITROGEN GAS
8. FLOW RATE, ml m-1 800
9. INLET PRESSURE, ATM 4
10. OUTLET PRESSURE, ATM 4
11. PRESSURE DROP, BAR
12. TEMPERATURE, °C 25
13. DESIGN TEMPERATURE 28
14. CV 312.5
15. OPENING (60-80) % (MAX FLOW RATE)
(>20%) (MIN FLOW RATE)
16. CLASS 400
REMARKS

61
10.6 Specification Sheet for Electro-Static Precipitator

Table 14. Specification Sheet for Electro-Static Precipitator

ESP SPECIFICATION SHEET DATE:

REF NO:
ITEM ESP
TYPE – SINGLE STAGE ESP
SERVICE
GEOMETRICAL DIIMENSION
S.N.
1. DIAMETER OF WIRE, METER 0.02
2. PLATE SPACING, METER 1
3. LEGHT OF ESP, METER 2.210
4. MATERIAL OF CONSTRUCTION Carbon steel
DESIGN PARAMETER

9. PARTICLE MIGRATING VELOCITY, ms-1 0.0762

10. SPECIFIC COLLECTION AREA, sm-1 0.0000136
11. ASPECT RATIO 1.33
12. POTENTAIL APPLIED, KV 20
13. COLLECTION EFFICIENCY 0.95
14. PERMITIVITY 8.85*10-12
15. DIFFUSION COEFFICENT, mss-1 1*10-2
16. RESISTIVITY, ohm- cm 1010
REMARKS

62
10.7 Specification Sheet for Cyclone Separator

Table 15. Specification Sheet for Cyclone Separator

CYCLONE SEPERATOR SPECIFICATION SHEET DATE:

REF NO:
ITEM CYCLONE SEPERATOR
MODEL – LAPPLE
SERVICE
GEOMETRICAL DIIMENSION
S.N.
1. DIAMETER, METER 1

2. HEIGHT OF INLET, METER 1

3. WIDTH OF INLET, METER 0.25

4. DIAMETER OF EXIST GAS, METER 0.5

5. LEGHT OF BODY, METER 2

6. LENGTH OF CONE, METER 2

7. DIAMETER OF DUST OULET 0.25

8. MATERIAL OF CONSTRUCTION IRON

DESIGN PARAMETER

9. NUMBER OF TURN 8
10. CUT POINT DIAMETER, METER 0.0000136
11. GAS RESIDENCE TIME, SEC 1.37
12. PARTICLE DRIFT VELOCITY, ms-1 0.18
13. TERMINAL DRIFT VELOCITY, ms-1 8.27
14. PRESSURE DROP, KPA 13.4
15. POWER REUIREMENT, WATT 68
16. INLET VOLUMETRIC FLOW RATE, m3s-1 0.005
REMARKS

63
10.8 Equipment Controlled by Programmable Logic Controller

Table 16. Equipment Controlled by PLC

PROGRAMMABLE LOGIC CONTROL EQUIPMENTS

"FBR VIA PYROLYSIS" CHECKED BY:
Client: DATE:
Location:
S.No ITEM NO. EQUIPMENT QTY SERVICE HANDLING REMARKS
NAME MATERIAL
TYPE
1 PLC-101 STORAGE 1 STORAGE SOLID
VESSEL
2 PLC-102 BELT 1 TRANSPORTATION SOLID
CONVEYER
3 PLC-103 SHREDDER 1 SIZE REDUCTION SOLID
4 PLC-104 SCREEN 1 SORTING SOLID
5 PLC-105 HOPPER 2 STORAGE SOLID
6 PLC-106 BUCKET 1 TRANSPORTATION SOLID
ELEVATOR
7 PLC-107 SCREW FEEDER 1 TRANSPORTATION SOLID
8 PLC-108 CYCLONE 1 PARTICULATE SOLID
SEPERATION SEPERATION
9 PLC-109 ELECTROSTATIC 1 PARTICULATE SOLID
PRECIPITATOR SEPERATION
ABBREVIATIONS
PLC- PROGRAMMABLE LOGIC CONTROL

64
10.9 List of Valves and their Specifications

Table 17. Valves with their Specification

Valve Schedule
FBR via Pyrolysis Date:
Checked by:
S. Tag Valve Name Service Size(inch) Fluid (State)
No No.
1 GV-1 Globe valve R-101 1 Nitrogen (G)
"
4
2 GV-2 Globe valve R-101 1 Nitrogen (G)
"
4
3 GV-3 Globe valve F-101 1" Nitrogen (G)
4 GV-4 Globe valve F-101 1" FUEL (G)
5 GV-5 Globe valve F-101 1" FUEL (G)
6 GV-6 Globe valve E-101 1 W (L)
"
2
7 GV-7 Globe valve V-101 1 OIL (L)
"
4
7 BV-1 Butterfly Valve E-101 1 W (L)
"
2
8 PRV-1 Pressure Relief R-101 1" HC (G)
Valve
9 PRV-2 Pressure Relief V-101 1" FG (G)
Valve
Abbreviations

Fluid state Fluid Name Equipment Tag

G: Gas FG: Fuel Gas R-101: Fluidized Bed Reactor
L: liquid W: Water F-101: Furnace
HC: Hydrocarbon E-101: Condenser
V-101: Liquid Vapor Separator

65
10.10 Piping and Insulation Specification [26]

Table 18.Piping and Insulation Specification

Required Pipeline code Insulation

Nominal Insulation
Stream Diameter Thickness
Diameter (in.) Type
(in.) (in.)
1
1 −N2 −SS304
Nitrogen 0.22 4 − −
4
1
1 −N2 −SS304
Nitrogen 0.22 4 − −
4
1
1 −N2 −SS304
4
Nitrogen 0.22 − −
4

Air 0.98 1 1−Air−SS304 − −

1
Water 0.5 1 −W−LUG316 − −
2
2
Vapor out 1−HC−LUG316
1 1 − −
from reactor

Vapor in to 1−HC−LUG316
1 1 − −
separator
1
− Fuel Gas SS
2
1 1 Cellular 1
Fuel Gas 0.402 304− 2 − CG Glass
2 2
1
− Fuel oil SS
1 4 1
1 Cellular
Fuel oil 0.2 304 − − CG
4 2 Glass 2

66
11. ECONOMIC ANALYSIS

It is necessary for any project to be economically viable to get a go-ahead. As a requirement of

any project, economic evaluation of this project is carried out as follows. All the values are on
NRs. [29]

1. Total Capital Investment

a. Reactor
Material of construction = SS 304
Assuming the weight of the reactor to be 3 tons.
Rate of SS 304 = 250 per kg
The cost of reactor comprising of four flanges, two heads and shell,
= 3000*250 = NRs. 750,000

b. Tubes
Material of construction = SS 316
Estimated weight = 20,000 Kg
Rate= 250/Kg
Cost = 20,000 * 250 = NRs. 50,00,000

c. Heat Exchanger
Material of Construction = Carbon Steel
Estimated Cost = NRs. 20,00,000

d. Liquid Vapor Separator

Material of construction = Carbon Steel
Estimated Cost = NRs. 20,00,000

e. Furnace/Burner
Material of Construction = refractory Bricks
Estimated Cost = NRs. 50,00,000

67
 f. Nitrogen Gas Storage Vessel
Material of construction = Carbon Steel
Estimated Cost = NRs. 1,00,000

g. Waste Plastics Storage

Estimated Cost = NRs. 50,000

h. Belt Conveyor
Estimated Cost = NRs. 5,00,000
i. Shredder
Estimated cost = NRs. 10,00,000

j. Hopper (2)
Estimated cost = 2*500000 = NRs. 10,00,000

k. Bucket Elevator
Estimated cost = NRs. 5,00,000

l. Screw Feeder
Estimated Cost = NRs. 2,50,000

m. Cyclone Separator
Estimated Cost = NRs. 10,00,000

n. Electrical Precipitator
Estimated cost = NRs. 10,00,000

o. Valves
Estimated Cost = 10* 50,000 = NRs. 5,00,000

Now, total cost of the equipment can be calculated as:

68
Total Cost = a + b + c + d + e + f + g + h + i + j + k + l + m + n + o = NRs. 2,06,50,000

Cost for pumps, vacuum pumps and ejectors, etc. may be assumed to be 40% of total cost.

i.e., cost of above-mentioned items (p) = 40% * 20,650,000 = NRs. 8,260,000

Total cost = a to p = 2,06,50,000 + 82,60,000 = NRs. 2,89,10,000

Taking fairly, Total Equipment Investment = NRs. 3,00,00,000 = NRs. 3 crores

11.1 Estimation of Fixed Capital Investment

Table 19. Fixed Capital Investment Estimation

Component Cost (NRs.)

1. Purchased Equipment costs (E) 3,00,00,000
2. Purchased Equipment Installation 1,20,00,000
Cost, 40% (E)
3. Instrumentation Installation Cost,
28%(E) 84,00,000
4. Piping (Installed), 28%(E) 84,00,000
5. Electrical (Installed), 45%(E) 1,35,00,000
6. Buildings, 22%(E) 66,00,000
7. Service Facilities, 55%(E) 1,65,00,000
8. Land,6%(E) 18,00,000
Total Direct Plant Cost(D) 9,72,00,000
9. Engineering and Supervision Cost,
32%(E) 96,00,000
10. Construction Expenses, 34%(E) 1,02,00,000
Total Indirect Cost(I) 1,98,00,000
Total Direct and Indirect Cost(D+I) 11,70,00,000
11. Contractor’s Fee, 5%(D+I) 58,50,000

69
 12. Contingency, 10%(D+I) 1,17,00,000
Fixed Capital Investment 13,45,50,000

Total fixed capital investment = NRs. 13.455 crore

= NRs. 13.5 crore

11.2 Working Capital Estimation

The working capital is around 25% of Total Capital Investment

Working Capital = FCI *0.25 = 13.5 crore * 0.25 = 3,37,50,000 = 3.4 crore

Hence, Total Capital Investment = 13.5 crore + 3.4 crore = 16.9 crore

Annual Operating Costs:

Assuming plant attainment is 80%

Then, operating time = 0.80 *365

= 292 days

= 7008 hours

Therefore, 73 days of shutdown of plant in a year.

1. Variable Cost

a. Raw material
i. Waste plastics =Rs. 10/Kg

Quantity per hour = 200 Kg

Total cost per year = 200*10*7008 = NRs. 1,40,16,000

70
 ii. Catalyst – HZSM-5 or ECat
Quantity of catalyst = 350 kg per day
Cost per Kg = Rs. 500
Total cost per year = 350*500*292 = NRs. 5,11,00,000

Total Raw material Cost per year = 1,40,16,000 + 5,11,00,000 = NRs. 6,51,16,000

b. Miscellaneous Cost

This is taken as 10% of maintenance Cost = 10% * 1,17,00,000 = NRs. 11,70,000

c. Utilities
i. Compressed Pure Nitrogen
Quantity per hour = 800ml/min*60 = 48 L
Cost = Rs 100/L
Total cost per year = 48*100*7008 = NRs. 3,36,38,400

ii. Rice husk

Quantity per day = 750 Kg = 31.25
Price per Kg = Rs. 20
Total cost per year = 20*750*292 = NRs. 43,80,000

iii. Water
Quantity per hour = 1000 Kg
Cost per Kg =Rs. 0.1
Total cost per year = 1000*0.1*7008 = NRs. 7,00,800

Total Utilities Cost = 3,36,38,400+43,80,000+7,00,800 = NRs. 3,87,19,200

Total Variable Costs = NRs. 65116000 + NRs. 1170000 + NRs. 38719200 = NRs. 10,50,05,200

2. Fixed Cost
d. Maintenance cost

10% of Direct and indirect cost = 10% * 11,70,00,000 = NRs. 1,17,00,000

71
 e. Operating labor Cost
Cost per month = NRs. 50,00,000
Cost per year = NRs. 7,00,00,000 (including bonus and 1 month extra for Dashain)

f. Plant overhead
It is assumed to be 50% of operating labor cost = 0.5* 7,00,00,000 = NRs.
3,50,00,000

g. Capital Charges
It is assumed to be 10% of FCI = 10% * 13.5 crore = NRs. 1.35 crore

Total Fixed Cost = d + e + f + g = Rs. 13,02,00,000

Total Production Cost = Variable cost + Fixed Costs = NRs. 13,02,00,000 + NRs. 10,50,05,200
= NRs. 23,52,05,200 = NRs. 23.6 crores

Assuming the Turnover Ratio of 2.5.

Turnover ratio = Gross annual Sales / Fixed Capital Investment

2.5 = Gross Annual Sales / 13.5 crore

So, Gross Annual Sales = 33.75 crores

Now,

Profit = Gross Annual Sales – Cost of Production

= 33.75 – 23.6 = 10.15 crores

Depreciation

Assuming salvage value of zero and service life of ten years.

So, depreciating by straight line method,

Depreciating per year = V/n = 13.5 /10

= 1.35 crores

72
11.3 Payout Period

So, Payout Period = Depreciable FCI / (Average Profit per year + Average Depreciation per
Year)

= 13.5/ (1.015 + 1.35)

= 5.7 years

The plant with above expanses and return is supposed to payout within 5.7 years.

11.4 Rate of Return (ROR)

Rate of return = (Average Profit per year/ Total Initial Investment) *100

= 1.015/16.9*100

= 6%

The plant is supposed to have rate of return of about 6% per annum with above consideration.

73
12. SAFETY ANALYSIS

While designing the plant for the conversion of plastics into fuel and oils via pyrolysis process, a
number of factors, viz. Chemical Toxicity, Worker's safety, Fire Hazard, and Leakage; Drainage
& Spillage, needs to be considered.
Plant is a general name for machinery, tools, appliances and equipment. It can include things as
diverse as presses in a foundry and computers in an office. It can range from electric drills to lifts
and escalators; from tractors to hand trolleys; cranes to commercial fishing nets and arc welding
gear.

Thoughtful design of plant can eliminate many of its risks to safety and health from the
beginning. Providing information on hazards and safe use of plant is vital. This can make users
aware of any risks the designer has been unable to eliminate, and ensure they don’t create any
new risks by not using the plant properly. [31]

The most important factors of plant layout as far as safety aspects are concerned are those to:

• Prevent, limit and/or mitigate escalation of adjacent events

• Ensure safety within on-site occupied buildings
• Control access of unauthorized personnel
• Facilitate access for emergency services

12.1 Fire Prevention

Our product of interest- Fuel and Oils is highly flammable in presence of open flames and
sparks, of heat and can cause fire under few uncertain conditions. Such threat can be prevented
by:
• Gas vents and drains for pipelines.
• Electrical wires must be properly earthen.
• Using proper insulation in pipelines.
• Installation of in-field fire extinguisher devices.
• Ignition sources like match box, lighters, cell phones should not be allowed in the plant.

74
12.2 Chemical Toxic Prevention

A number of Chemical compounds are released during the pyrolysis process, which can cause
serious threat to human health and equipment degradation when leaked or spilled. This level of
hazard can be prevented using the flowing measures:

• Use of Personal Protective Equipment (PPE)

• Orientation on Material Safety Data Sheet and ISO training program for working
personals.
• Developing Source models to prevent any instantaneous release of toxic chemicals.
• Scrubber to avoid harmful gases to release into the atmosphere

12.3 Physical Aspects

This includes falling of heavy machinery and equipment as well as degradation of material by
corrosion and several environmental factors. Preventive measures include:

• Time-to-Time Maintenance of Equipment and Instruments.

• Use of Safety helmet by working professionals.
• Prevent corrosion by effective coating.

75
12.4 HAZOP Analysis [30]
Hazards identification and risk assessment studies can be performed during the initial design of a process. Various events are
suggested for a specific piece of equipment with the participants determining whether and how the event could occur and whether the
event creates any form of risk.
In this design process, the fuel gas and oil are generated from plastic waste through a pyrolysis mechanism. A number of equipment
are involved in this change process, and given the parameters for their operation, this equipment is highly subjected to risk and can
cause serious damage under some uncertain situation. Prior to designing of the process, a HAZOP (Hazard and Operational) study can
be done to identify likely threat and their possible consequences. Analysis of such risk can be done to prevent any potential damage in
future endeavor.

Table 20. HAZOP Analysis

S. No. Section Parameter Guide Deviation Cause Consequences Action

word

1. Heat Flow NO Absence of Butterfly valve High temperature High Temperature

exchanger cooling water fully closed of Process fluid alarm

Coolant missing Damage to Emergency

sensors and shutdown
internals.

Less of Less coolant Pipe Blockage In-sufficient High Temperature

flow condensation alarm
Valve partially
Closed Difficulty in Emergency
Products shutdown
Separation

76
 Failure of
Controller

Leakage from pipe

More of More coolant Failure of Lesser Low Temperature
flow Butterfly valve temperature of alarm
Process fluid
Failure of Perform regular
controller maintenance

Temperature Less of High Insufficient Low Product Low Temperature

Temperature of Coolant Quality alarm
process Fluid
Failure of Perform
Temperature Maintenance for
Gauge valve and pipes.

Failure of
Controller

More of High Insufficient Internal parts Installation of high

Temperature of Coolant Damage temperature alarm
process Fluid
Failure of In-sufficient Adjust flow rate
Temperature condensation for coolant
Gauge
Difficulty in
Products
Separation

77
2. Separator Level Less of Liquid level low Insufficient Priming in Pump Perform
condensation maintenance of
Instruments
Leakage
Low yield of Calibrate sensors
Failure of Level product
sensors Increase coolant
flow into the
Pump failure reactor

More of Liquid level high Blockage at outlet Escaping of Oil Perform

through the Gas maintenance of
Failure of Level Discharge section Vessel and
sensors Instrument
High pressure
Pump failure build-up within Calibrate sensors
the vessel

Corroding of
Demister Pad
3. Furnace Flow NO Lack of Fuel Valve and No combustion Installation of Low
controller failures Temperature alarm
Lack of Air
Valve maintenance
or replacement

Less of Lesser fuel into Valve partially Insufficient Regular

Furnace closed combustion maintenance of

78
 Lesser fuel into Leakage from pipe Internal damage Pipes and
Furnace Pipelines
Blockage of the
outlet stream Valve maintenance
or replacement
More of More fuel into Failure of Valves Over-Combustion Valve maintenance
Furnace
Inappropriate Pipe Internal parts Installation of
More fuel into sizing damage High Temperature
Furnace alarm
Escape to open
Installation of
properly sized
pipes.

Temperature Less of Insufficient Sensors failures Insufficient Sensor calibration

Temperature combustion
inside furnace Lack of Fuel or Flow Controller
Air Reaction maintenance
temperature not
Cold weather reached Perform of EIA
Condition before Installing
plant
Loss of
heating(leakages)

79
 Ineffective
isolation
More of High Excess of Fuel Over-Combustion Install temperature
temperature than indicator
expected inside Hot Weather Reactor damage
furnace Environment in Upgrade isolations
Plant location Internal parts
damage Attention of heat
Sensors Failure input and output

4. Reactor Pressure Less of Lesser Pressure Leakage of Gas Low efficiency of Install pressure
inside Reactor operation indicators
Inappropriate
Insulation Install low level
alarm
Pressure gauge
failure Regularly done
maintenance

High of High Pressure Blockage at outlet Rupture the Install pressure

inside Reactor stream column indicators

Pressure relief Product and Installation

valve catalyst loss pressure relief
malfunctioning valve

80
 Perform regular
maintenance

Emergency
shutdown
Temperature High of Lesser Failure of sensors Loss of product Instruct operation
Temperature procedure
inside Reactor Blockage at outlet Change of
stream product quality Attention of heat
input and output

Install high level

alarm system
Low of High Failure of sensors Reaction Install temperature
Temperature temperature not indicator
inside Reactor Lack of Fuel or reached
Air Upgrade isolations
Change in
Cold weather product quality Attention to heat
Condition input and output
(reflux, vapor and
Loss of feed in)
heating(leakages)
Properly done
maintenances and
operations

Install low level

alarm

81
13. RECOMMENDATION

Despite the recent advancements in plastic conversion technology, several issues remain. A major
challenge with the production of fuel from plastic solid waste is the presence of PVC, which
produces HCl gas during pyrolysis. However, researchers have been able to remove chlorine to
some extent by using HCl adsorbents to pretreat the plastics. A better method to remove chlorine
production and its adsorption should be fashioned.

Catalysts will also need improvement. For example, it will be useful to use dual catalysts with a
combination of high acidic properties, porosity and hydrogenation properties, identify accessible
and to prevent deactivation and increase catalyst reuse. In fact, the use of metal-loaded biochar
may partly mitigate the high cost of catalysts.

It is very important to devise efficient methods to produce fuel from mixed plastics, or to exclude
or remove PET and PVC from mixed plastics before pyrolysis. The product yield and quality can
be improved by finding alternative heating modes. A thorough study of the effect of heating rates
on product yields and distribution will be very important to produce fuel-range hydrocarbons.

It can be assumed that a well-run curb side recycling program or landfilling can cost, under general
circumstances, between Rs. 5000 and Rs. 15000/ton. Therefore, the cost of recycling plastic is
relatively in expensive compared to the production of fuel from plastic and the cost of fossil fuel
is currently cheaper than the production of fuel from plastics. So, government itself should show
interest to discourage landfilling and motivate and encourage fuel oil and fuel gas production.

Better study and manipulation of parameters for better design of reactor and use of cost-effective
catalyst should be advised. Proper maintenance of plant and smooth functioning is a most. The
catalyst regeneration could save a fortune. So, better methods and proper study to regenerate the
catalyst should be carried out.

82
14. CONCLUSION

Fuel production from plastics is attractive because it simultaneously addresses the issues of waste
management and alternative energy generation. This process used a mixture of LDPE (Low
Density Poly Ethylene), HDPE (High Density Poly Ethene), PP (Poly Propylene) and PS (Poly
Styrene) to produce fuel oil and fuel gas. A fluidized bed catalytic reactor for plastic pyrolysis has
been designed. The system also comprises of condenser, gas – vapor separator, and husk fired
burner as major equipment. This reactor designed is more compact and smaller in size compared
to the existing reactors. The reactor is able to process about 3.2 tons of specific plastics and produce
80.3% of fuel gas, 7.4% of fuel oil and about 12.3% of solid residue. Process and design parameters
can be varied to give product ratio in desired proportion. Different catalysts could also be used to
produce desired amount of fuel oil and fuel gas. But, changing the catalyst could bring further
complication on fluidized bed formation.

The catalyst used can also be regenerated and further used for several times. This reduces cost on
catalyst and as a whole cost of production. The produced fuel gas could be purified and used as
household and factory fuel. The produced fuel oil can also be further processed to produce
synthetic fuel oil. The synthetic fuel oil has lower carbon emission ratio, this can on one hand
manage the waste plastic problem to some extent and on other hand can also reduce global
warming process.

The project has a fixed capital investment requirement of about 14 crores and cost of production
of about 24 crores per annum. If the capital could be arranged and suitable site be selected, the
plant can get a go ahead and produce the aforementioned quantity of fuel oil and fuel gas. The
plant has the payout period of about six years and its life span is at least 10 years producing the
profit of about 10 crores per annum. The rate of return of the project is estimated to be about 6%.

83
15. REFERENCE

[1] Qualman, D. (2019, Sept 16). Global plastic production, megatonnes, 1917 to 2017.
Retrieved from https://www.darrinqualman.com/global-plastics-production/
[2] Times, T. H. (2019, Aug 22). Everest region bans single-use plastic to reduce waste.
Retrieved from The Himalayan Times: https://thehimalayantimes.com/nepal/everest-
region-bans-single-use-plastic-to-reduce-waste/
[3] Bamido, A. (2018). Design of A Fluidized Bed Reactor For Biomass Pyrolysis. Texas: Alaba
Bamido.
[4] Julliand, V. (2018, May 05). The Kathmandu Post. Retrieved from A Plastic World:
https://kathmandupost.com/opinion/2018/06/05/a-plastic-world
[5] Ikram, T. (2014, Nov 18). Nepal plastic industry seen growing 10-11% in 2015-2016.
Retrieved from https://www.icis.com/explore/resources/news/2014/11/18/9839336/nepal-
plastic-industry-seen-growing-10-11-in-2015-2016/
[6] Thought.co. (2019, May 16). Retrieved from plastic and its composition:
https://www.thoughtco.com/plastic-chemical-composition-608930.
[7] Project, P. G. (2019, Jan 22). Material science of plastic. Retrieved from
https://www.plasticgarbageproject.org/en/plastic-life
[8] Li, H. (2017). Applications of Lumping Kinetics Methodology to Plastic Waste Recovery via
Pyrolysis. Haoyu Li.
[9] Haig, S. (2014). Plastics to oil Products. Zerowastescotland.
[10] Sulistyo, H. (2019). Kinetics Modeling of Waste Plastic Mixture Pyrolysis for Liquid Ful
Production. International Journal of Innovative Technology and Exploring Engineering,
1116-1120.
[11] S. M. Al-Salem, P. L. (2010). Kinetics of Ployethylene Terephthalate (PET) and
Polysteryne (PS) Dynamnic Pyrolysis. World Academy of Science, Engineering and
Technology, International Journal of Chemical and Molecular Engineering , 402 - 410.
[12] Lin, Y. H. (2005). Catalytic Reactions of Post-consumer polymer waste over fluidised
cracking catalysts for producing hydrocarbons. Journal of Molecular Catalysis A:
Chemical 231 , 113-122.
[13] Miandad, R. (2016). Catalytic pyrolysis of plastic waste : A review. Process Safety and
Environmental Protection, 822-838.
[14] A. G. Buekens, H. H. (1998). Catalytic plastics cracking for recovery of gasoline-range
hydrocarbons from municipal plastic wastes . Resources, Conservation and Recycling ,
163-181.

84
[15] B. K. T, S. (2015). Reactor Design for Conversion of Waste Plastic into Fuel Oil and Gas.
B. K. T, Samarasiri.
[16] Moore, C. (2019, Feb 14). Plastic pollution. Retrieved from
https://www.britannica.com/science/plastic-pollution
[17] Engineering, I. (2019, JUN 18). Retrieved from https://interestingengineering.com/how-to-
eliminate-plastic-waste-and-plastic-pollution-with-science-and-engineering
[18] Environmental Standards for Ambient air, Automobiles, Fuels, Industries and Noise. (2000)
[19] Government, N. (1997). Environmental Protection Act, 1997.
[20] Chemistry, E. (2017, Jun 12). Chemical Formula of zeolite. Retrieved from
https://eduladder.com/viewquestions/3552/What-is-the-chemical-formula-of-zeolite
[21] Himmelblau, D. M. (2012). Basic Principle and Calculation in Chemical Engineering.
Prentice Hall.
[22] Smith, J. M., Van Ness, H. C., & Abott, M. M. (2016). Introduction to Chemical
Engineering Thermodynamics. McGraw Hill Education.
[23] Singh, P. R. (2012). Study on Thermal Pyrolysis on Medical Waste for the production of
Useful Liquid Fuel. Prof. R. K. Singh.
[24] Shawabkeh, D. R. (2015). Steps for design of furnace. Researchgate.com.
[25] Sinnot, R., & Towler, G. (2015). Chemical Engineering Design. Elsevier
[26] Park, K. Y. (2018). Teaching Material #5. Nepal.
[27] Bashil, K. (2015). Design and Febrication of Cyclone Separator. Shanghai:
Researchgate.com.
[28] Define Instruments. (Jan 2019). Temperature Transmitters. Retrieved from Define
Instruments: http://www.defineinstruments.com/pages/temperature-
transmitters?fbclid=IwAR0hHv5fnM-
n2UNLXTLscUZ8wqhFuWTauAiXVevZVHzG1aFKuG4ZcG23Ti8
[29] Max S. Peters, K. D. (1991). Plant Design and Economics for Chemical Engineer, 4th
Edition. McGraw Hill Publication.
[30] Daniel A. Crowl, J. F. (2002). Chemical Process Safety: Fundamentals with Application.
Prentice Hall.
[31] Australia, G. o. (2001). Plant Design: Making it safe. Worksafe Wastern Australia.
[32] McCabe, Thiele (2012). Unit Operations for Chemical Engineers: McGraw Hill
[33] Fougler, H. S. (2006). Elements of Chemical Reaction Engineering . Pearson Education.

85
16. APPENDIX

16.1 Appendix A: Abbreviation

CO Carbon Monoxide
N2 Nitrogen Gas
CO2 Carbon Dioxide
PP Polypropylene
PE Polyethylene
PS Polystyrene
SPI Society of Plastic Industry
PET/PETE Polyethylene Terephthalate
HDPE High Density Polyethylene
LDPE Low Density Polyethylene
PVC Polyvinyl Chloride
BPA Bisphenol A
CFC Chloro-Fluro Carbon
ZSM Zeolite Socony Mobil
FCC Fluid catalytic cracking
HZSM Protonic form of Zeolite Socony Mobil
ASME American Society of Mechanical Engineer
TEMA Tubular Exchanger Manufacturers Association
FTIR Fourier-transform Infrared Spectroscopy
FBR Fluidized Bed Reactor
PFD Process Flow Diagram
PLC Programming Logic Controller
P&ID Piping & Instrumentation Diagram
KW Kilo watt
KJ Kilo Joule

86
kg Kilogram
AFR Air to Fuel Ratio
KV Kilo Volt
SCA Specific Collection Area
AR Aspect Ratio
SS Stainless Steel
TG Temperature Gauge
TT Temperature Transmitter
TIC Temperature Indicator Controller
TY Temperature Transducer
FI Flow Indicator
FT Flow Transmitter
FIC Flow Indicator Controller
FY Flow Transducer
HC Hydrocarbon
NG Natural Gas
CS Carbon Steel
TFP-GI: Gas Turbine Flow Meter
PPS Polyphenylene Sulfide
AO Analog Output
DO Digital Output
PPS Polyphenylene Sulfide
FCV Flow Control Valve
TCV Temperature Control Valve
PG Pressure Gauge
ID Internal Diameter
OD Outside Diameter
ND Nominal Diameter

87
atm Atmospheric Pressure
K Kelvin
Cr Chromium
Ni Nickel
GV Globe Valve
BV Butterfly Valve
PRV Pressure Relief Valve
FG Fuel Gas
CG Cellular Glass
PPE Personal Protective Equipment
ISO International Organization for Standardization
HAZOP Hazard and Operational
EIA Environment Impact Assessment
FCI Fixed Capital Investment
ROR Rate of Return
NRs Nepali Rupees

88
16.2 Appendix B: Constant Values and Nomenclature

Table 21. Symbols and their Meaning

S. No. Symbols Parameter Value Unit

1. ∆𝐻𝑓⁰ Heat of formation KJ kg-1
2. M Mass flow rate kg h-1

3. ῠ Stoichiometric Positive for

coefficient products and
negative for
reactants
4. 𝐶𝑝 Specific Heat Capacity KJ kg-1K-1
5. 𝜌 Average density of 1684.17 kg m-3
particle and catalyst
6. ε Void fraction 0.4
7. h Total Bed height 1 M
8. A Cross Section Area m2
9. 𝑀𝑠 Mass of catalyst 266.65 kg
10. 𝑔 Acceleration due to 9.8 ms-1
gravity
11. L Length of reactor 2.94 M
12. D Diameter of reactor 0.9 M
13. ℎ𝑐 Height of catalyst 0.2 M
14. ℎ𝑝 Height of plastic 0.8 M
15. 𝜌𝑔 Density of fluidizing 2 kg m-3
gas
16. 𝑑𝑝 Particle diameter 130 𝜇𝑚
17. 𝜇𝑓 Viscosity of fluidizing 0.000013 Pa. s
gas
18. u Superficial velocity 0.49-0.21 ms-1
19. ut Terminal velocity 0.49 ms-1
20. 𝑢𝑚𝑓 Minimum fluidization 0.21 ms-1
velocity
21. 𝜑 sphericity 1
22. hmin Minimum Fluidization 1 M
Height
23. ∆Pb Fixed Bed Pressure 0.089 atm
Drop
24. ∆Pd Distributed plate 0.0267 atm
pressure drop
25. V Volume of Reactor 1.71 m3
26. P Maximum pressure 4 atm
27. S Maximum allowable 52500000 Nm-2
Stress
28. E Joint Efficiency 0.6

89
29. 𝜎 Yield strength 210*106 Nm-2
30. f Safety factor 4
31. C Corrosion allowance 4.76 mm
32. CD Orifice coefficient 0.5
33. uo Gas velocity through 26.07 ms-1
orifice
34. do Diameter of orifice 3 mm
35. dn Diameter of nozzle 10 mm
35. lm Minimum nozzle 36.27 mm
height
36. hi Nozzle Height 72.54 mm
37. 𝑃𝑝𝑙𝑎𝑡𝑒 Pressure in plate 26666.5 pa
38. Tn Nozzle thickness 1.62 mm
39. tp Thickness of 15.76 mm
distributor plate
40. Q Total heat required for 114.68 KW
cracking
41. f Fuel value 12600 KJ kg-1
42. Qf Heat liberated 163.8 KW
43. ἠ Fuel Efficiency 0.70
44. 𝑀𝑓𝑢𝑒𝑙 Mass of fuel 748.8 kg day-1
45. AFR Air to fuel ratio 4.7
46. 𝑀𝑎𝑖𝑟 Flow rate of air 3519.36 kg air day-1
47. 𝑀𝑇𝑎𝑖𝑟 Total air required 4400 kg air day-1
48. Qair Heat provided by air 1.39 KW
49. (Cp)air Heat capacity of air 1.85 KJ kg-1K-1
50. Tg Inlet Temperature 25 K
51. Tr Reference temperature 15.5 K
52. Qwall Heat Radiated through 3.3 KW
wall
53. Qh Heat of exhaust gas 95.32 KW
54. G Air to fuel ratio 4.7
55. Tg Flue gas temperature 1751.67 R
56. Q1 Net heat liberated 66.57 KW
57. 𝐶𝑝1 Heat capacity of 1.28 KJ kg-1K-1
Nitrogen
58. 𝐶𝑝2 Heat capacity of water 4.2 KJ kg-1K-1
59. 𝐶𝑝3 Heat capacity of 2.15 KJ kg-1K-1
carbon dioxide
60. 𝑃𝑑 Draft 12.7 mm H2O
61. P Pressure 1013.25 mbar
62. 𝑇𝑎 Ambient Temperature 298.15 K
62. 𝑇𝑔𝑎 Flue gas temperature 700 °C
63. 𝐿𝑠 Stack Height 16 M
64. (𝐶𝑝 )𝑔𝑎𝑠 Heat capacity of 0.5 KJ kg-1K-1
hydrocarbon vapor

90
65. 𝑚𝑔 Mass flow rate of 160.6 kg h-1
hydrocarbon
66. (𝑐𝑝 )𝑜𝑖𝑙 Heat capacity of Fuel 1.75 KJ kg-1K-1
oil
67. 𝑚𝑙 Mass flow rate of fuel 14.8 kg h-1
oil
68. 𝐿𝑓𝑢𝑒𝑙 Latent Heat of 263 KJ kg-1
vaporization
69. ∆𝑇𝑙𝑚 Log mean 95.90 °C
Temperature
70. Ft Correction Factor 0.96
71. L1 Length of tube 1.83 M
72. d10 Outer diameter of tube 16 mm
73. dli Inner dimeter of tube 12 mm
74. Ua Trail overall heat 150 W m-2 K-1
transfer co efficient
75. 𝑇𝑚 Corrected log mean 30 °C
Temperature
difference
76. N Number of tubes 10
77. 𝜌watet Density of water 995.6 kg m-3
78. hi Tube side coefficient 2451.45 W m-2°C-1
79. kf Thermal conductivity 0.59 Wm-1°C-1
of water
80. Re Reynold’s Number
81. 𝜇𝑤 Dynamic viscosity of 0.8*10-8 Pa s
water
82. Pr Prandtl’s Number
83. Jn Heat transfer factor
84. Pt Pitch 20 mm
85. K Pitch Factor 0.249
86. n Number of passes 2.207
87. Ds Shell inside diameter 135.27 mm
88. 𝑙𝐵 Baffle spacing 27.05 mm
89. 𝐺𝑠 Shell side mass 69.6 kg m-2s-1
velocity
90. 𝑑𝑒 Equivalent diameter 1.36 mm
91. 𝑇𝑠ℎ𝑒𝑙𝑙 Mean Shell side 212.5 °C
temperature
92. 𝜇 Dynamic viscosity of 7*10-5 Pa s
hydrocarbon vapor
93. (𝑘)𝑔𝑎𝑠 Thermal conductivity 0.1385 Wm-1°C-1
of hydrocarbon vapor
95. hs Shell side heat transfer 261.45 W m-2°C-1
coefficient

91
96. 𝑈0 Calculated overall heat 202 Wm-2K-1
transfer coefficient
97. ℎ0𝑑 Outside fouling factor 5000 W m-2 °C-1
98. ℎ𝑖𝑑 Inside fouling factor 4000 W m-2 °C-1
99. jf Frictional Factor
101. Np Number of pass 2
102. 𝜌𝑤 Density of water 996.5 kg m-3
103. 𝑢𝑡 Tube side fluid 0.47 ms-1
velocity
104. ∆𝑃𝑡 Tube side pressure 2.16 Kpa
drop
105. 𝑢𝑠 Shell side Velocity 8.03 ms-1
106. ∆𝑃𝑠 Shell side pressure 7.2 Kpa
drop
107. 𝜌𝑙 Density of fuel oil 740 kg m-3
108. 𝜌𝑣 or 𝜌𝑔 Density of 8.66 kg m-3
hydrocarbon vapor
109. u1t Settling velocity 0.64 ms-1
110. Q1 Vapor flow rate in 0.005 m3s-1
liquid vapor separator
111. Dv Minimum Vessel 2.58 m
Diameter
112. N1 Number of turns inside 8
device
113. Dpc Cut point diameter 13.36 𝜇𝑚
114. νi Velocity of gas 18.28 ms-1
115. Vt Terminal drift velocity 8.27 ms-1
116. P Pressure drop 13.4 K pa
117. Wf Power Requirement 68 W
118. w Particle migration 0.25 fts-1
velocity
119. AR Aspect Ratio 1.33
120. Q2 Volumetric Flow Rate 0.005 m3s-1
in Cyclone

92
16.3 Appendix C: Instruments Symbol

Table 22. Instrument Symbol

Symbol Instrument
FY Flow Transducer
FIC Flow Indicator Controller
FT Flow Transmitter
FI Flow Indicator
RY Ratio Controller
TIC Temperature Indicator Controller
TT Temperature Transmitter
PG Pressure Gauge
TG Temperature Gauge
TY Temperature Transducer
TCV Temperature Control Valve
FCV Flow Control Valve

16.4 Appendix D: Equipment Symbol

Table 23. Equipment Symbol

Symbol Instrument
PLC-101 Storage
PLC-102 Belt Conveyer
PLC-103 Shredder
PLC-104 Screen
PLC-105 Hopper
PLC-106 Bucket Elevator
PLC-107 Screw Feeder
PLC-108 Cyclone Separator
PLC-109 Electrostatic Precipitator
RV-101 Rotatory Valve

93