Manufacture of Maleic Anhydride: Chemical Engineering
Manufacture of Maleic Anhydride: Chemical Engineering
Manufacture of Maleic Anhydride: Chemical Engineering
BACHELOR OF TECHNOLOGY
in
CHEMICAL ENGINEERING
by
CHANDRU.V (10704002)
ANURAJ.R (10704022)
under the guidance of
Mrs.E.Poonguzhali, B.Tech.,
(Lecturer, School of Chemical Engineering)
FACULTY OF
ENGINEERING AND TECHNOLOGY
SRM UNIVERSITY
(under section 3 of UGC Act,1956)
SRM Nagar, Kattankulathur 603 203
Kancheepuram Dist.
MAY 2008
BONAFIDE CERTIFICATE
Certified that this project report MANUFACTURE OF MALEIC
ANHYDRIDE is the bonafide work of CHANDRU.V (10704002), ANURAJ.R
(10704022) who carried out the project work under my supervision.
INTERNAL GUIDE
Date:
EXTERNAL EXAMINER
INTERNAL EXAMINER
Date :
ACKNOWLEDGEMENT
2
ACKNOWLEDGEMENT
First of all, we thank Dr.C.Muthamizhselvan, Associate Director, S.R.M
University (Engg & Technology) for allowing us to work on this project.
We are extremely thankful to Dr.R.Karthikeyan, B.E., PhD, Professor and
Head,
venture on this project and providing us with good support and guidance.
We would like to thank Mrs.E.Poonguzhali B.Tech, , Faculty, School of
Chemical Engineering, S.R.M University, for her encouragement and guidance at all
stages of this project.
We would like to thank the management and staff of E.I.D Parry (India)
Limited, Pudukottai, for their valuable assistance.
We extend our sincere thanks to all the staff members of the School of
Chemical Engineering, S.R.M University, for their support and assistance.
CONTENTS
Page no
1. INTRODUCTION
2. PROPERTIES
3. APPLICATIONS
4. PROCESS DESCRIPTION
5. MATERIAL BALANCE
16
6. ENERGY BALANCE
20
7. DESIGN
25
8. PROCESS CONTROL
AND INSTRUMENTATION
9. SAFETY AND LOSS PREVENTION
33
37
41
46
12. CONCLUSION
55
13. REFERENCE
57
INTRODUCTION
INTRODUCTION
The dominant end use of Maleic anhydride (MA) is in the production of
unsaturated polyester resins. These laminating resins, which have high structural
strength and good dielectric properties, have a variety of applications in automobile
bodies, building panels, molded boats, chemical storage tanks, lightweight pipe,
machinery housings, furniture, radar domes, luggage, and bathtubs. Other end
products are fumaric acid, agricultural chemicals, alkyd resins, lubricants,
copolymers, plastics,succinic acid, surface active agents, and more. In the United
States, one plant uses only n-butane and another uses n-butane for 20 %of its
feedstock, but the primary raw material used in the production of Maleic Anhydride is
benzene. The Maleic Anhydride industry is converting old benzene plants and
building new plants to use n-butane. Maleic Anhydride also is a byproduct of the
production of phthalic anhydride. It is a solid at room temperature but is a liquid or
gas during production. It is a strong irritant to skin, eyes, and mucous membranes of
the upper respiratory system.
The model Maleic Anhydride plant, as described in this section, has a
benzene-to- Maleic Anhydride conversion rate of 97.7 percent. Because of a lack of
data on the n-butane process, this discussion covers only the benzene oxidation
process.
History
In OSHA Method 25 , Maleic anhydride is collected and derivatives on p-anisidinecoated XAD-2 tubes. An untreated XAD-2 tube is connected in series to trap the p-anisidine
that is partly leached from the first tube during sampling. In trying to develop sampling and
analytical methods for a series of anhydrides (acetic, maleic, phthalic, and trimellitic),
derivatizing agents other than p-anisidine were investigated to obviate the use of the second
tube. 1-(2-Pyridyl)piperazine, the agent used in earlier methods for a series of isocyanates was
considered. A sampling method for acetic anhydride was validated using this derivatizing
agent. With maleic and other anhydrides, however, this reagent was found to be unsatisfactory
due to the instability of its derivatives. After a brief survey, veratrylamine was selected
because: (1) it readily forms relatively stable acid-amides with these anhydrides, (2)it does not
leach from the glass fiber filters impregnated with it, even at a flow of 1 liter per minute, and
(3) its cost is reasonable. The sampling device consists of two filters which are separated by a
center support section Samples are collected closed-face to minimize contamination.
PROPERTIES
PROPERTIES
Chronic Toxicity Summary
Inhalation reference exposure level
C4H2O3
Molecular weight
98.06 g/mol
Boiling point
202C
Melting point
52.8C
52.5 g/100 g
Chloroform,
50 g/100 g benzene,
APPLICATIONS
10
Applications
The annual statewide industrial emissions from facilities reporting under the
Air Toxics Hot Spots Act in California based on the most recent inventory
were estimated to be 7366 pounds of Maleic anhydride.
11
PROCESS DESCRIPTION
12
PROCESS DESCRIPTION
Maleic anhydride was first commercially produced in the early 1930s by the
Vapor-phase oxidation of benzene. The use of benzene as a feedstock for the
production of Maleic anhydride was dominant in the world market well into the
1980s. Several processes have been used for the production of Maleic anhydride from
benzene with the most common one from Scientific Design. Small amounts of Maleic
acid are produced as a by-product in production of Phthalic anhydride .
This can be converted to either Maleic anhydride or fumaric acid. Benzene,
although easily oxidized to maleic anhydride with high selectivity, is an inherently
inefficient feedstock since two excess carbon atoms are present in the raw material.
Various C4 compounds have been evaluated as raw material substitutes for benzene in
the production of maleic anhydride. Fixed- and fluid-bed processes for production of
maleic anhydride from the butenes present in mixed C4 streams have been practiced
commercially. None of these processes is currently in operation. Rapid increases in
the price of benzene and the recognition of benzene as a hazardous material
intensified the search for alternative process technology in the United States. These
factors led to the first commercial production of maleic anhydride from butane at
Monsanto's J. F. Queenly plant in 1974. By the early 1980s, the conversion of the
U.S. Maleic anhydride manufacturing capacity from benzene to butane feedstock was
well under way using catalysts developed by Monsanto, Denka, and Halcon. One
factor that inhibited the conversion of the installed benzene-based capacity was that
early butane-based catalysts were not active and selective enough to allow the
conversion of benzene-based plant without significant loss of nameplate capacity. In
1983, Monsanto started up the world's first butane-to-Maleic anhydride plant,
incorporating an energy efficient solvent-based product collection and refining
system. This plant was the world's largest Maleic anhydride production facility in
1983 at 59,000t/yr capacity, and through rapid advances in catalyst technology has
been debottlenecked to a current capacity of 105,000t/yr (1999). Advances in catalyst
technology, increased regulatory pressures, and continuing cost advantages of butane
over benzene have led to a rapid conversion of benzene- to butane-based plants.
13
14
alumina, or silica, and is of low surface area . Supports with higher surface area
adversely affect conversion of benzene to Maleic anhydride. The conversion of
benzene to Maleic anhydride is a less complex oxidation than the conversion of
butane, so higher catalyst selectivitys are obtained. The vanadium oxide on the
surface of the support is often modified with molybdenum oxides. There is
approximately 70% vanadium oxide and 30% molybdenum oxide in the active phase
for these fixed-bed catalysts. The molybdenum oxide is thought to form either a solid
solution or compound oxide with the vanadium oxide and result in a more active
catalyst.
4.5O2
Benzene
Oxygen
C4H2O3 +
Maleicanhydride
2H2O + 2CO2
Water
Carbon- dioxide
15
dibutyl phthalate. Some processes may use a double-effect vacuum evaporator at this
point.Waste gas from the absorber contains unreacted benzene and O2, N2, CO2, and
H2O, plus some dibutyl phthalate . This Maleic Anhydride is then combined in
storage with that from the separator. The molten product is aged to allow colorforming impurities to polymerize. These are then removed in a distillation column,
leaving the finished product.In the distillation column separation of maleic anhydride
and dibutyl phthalate 99 mol % of maleic anhydride separates and send to storage
tank. MA product is usually stored in liquid form, although it is sometimes flaked and
palletized into briquettes and bagged.[Reference : 2]
Nearly all emissions from MA production are from the main process vent of the
product recovery absorber, the largest vent in the process. The predominant pollutant
is unreacted benzene, ranging from 3 to 10 percent of the total benzene feed. The
composition of uncontrolled emissions from the product recovery. The refining
vacuum system vent,the only other exit for process emissions. Benzene oxidation
process emissions can be controlled at the main vent by means of carbon adsorption,
thermal incineration, or catalytic incineration. Benzene emissions can be eliminated
by conversion to the n-butane process. Catalytic incineration and conversion from the
benzene process to the n-butane process are not discussed for lack of data. The vent
from the refining vacuum system is combined with that of the main process as a
control for refining vacuum system emissions. A carbon adsorption system or an
incineration system can be designed and operated at a 99.5 %removal efficiency for
benzene and volatile organic compounds.
The entire Maleic anhydride process should be optimized using decision
variables of your choosing. Decision variables should be chosen as the design
variables most strongly affecting the objective function. There are topological
optimization and parametric optimization. In topological optimization, which is
usually done first, the best process configuration is chosen. Parametric optimization
involves varying operating variables and should be done after topological
optimization is complete. Some examples of parameters that can be used as decision
variables are reactor temperature, pressure, and conversion; absorber temperature and
pressure; and distillation column reflux ratio.
16
17
EQUIPMENTS
Compressor
The compressor increases the pressure of the feed air to approximately 12 atm. The
compressor may be assumed to be adiabatic with an efficiency of 75%. It may be
necessary to use staged compressors with inter cooling.
Heat Exchanger
This heat exchanger vaporizes the benzene feed to saturated vapor at the stream
pressure, which you must choose based on the optimization in mini-design #1.
Fired Heater
This heats reactor feed vapor to reaction temperature. Natural gas is used as the
fuel, and the amount needed is based on the LHV of natural gas and the process heat
load. The cost of natural gas is a utility cost, and you should assume that the fired
heater is 85% efficient.
Reactor Information
The reaction conditions are limited to temperatures between 450C and 650C.
Table 1 gives conversion and selectivity information for the reactor. It should be
observed that CO2, the undesired product, is also formed in the desired reaction.
Therefore, the maximum possible selectivity, defined as maleic anhydride
formed/total CO2 formed, is 0.5.
18
Thermodynamics of components
The separations section of this process involves dibutyl phthalate, maleic
anhydride, maleic acid, and quinone. It is necessary to understand the vapor-liquid
equilibrium between different pairs of these components. Specifically, you are to
investigate the vapor-liquid equilibrium between maleic anhydride and quinone,
maleic anhydride and maleic acid, and maleic acid and dibutyl phthalate. First of all,
check different thermodynamics packages in Chemcad to see if there are differences
between the predictions of the packages. The term thermodynamics package means
the choice of K-value and enthalpy calculation methods. At a minimum, you should
investigate ideal, SRK, Peng-Robinson, UNIQAC, UNIFAC, UNIFAC/UNIQAC,
plus the recommendation of the expert system if it differs from those listed above.
Specifically, examine the T-xy diagrams of the pairs of components using the same
thermodynamics packages at a variety of possible operating pressures (1-10 atm) for
the separation section. The presence of azeotropes strongly affects the ability to do
separations.
19
properties in the Chemcad data base do not match those in other published data bases.
Please investigate this problem in depth and determine which information is correct.
If the Chemcad data base is in error, discuss how the vapor-liquid equilibrium results
would be affected.
MATERIAL BALANCE
20
MATERIAL BALANCE
Molecular weight of C6H6
=78
Molecular weight of O2
=32
=98
=44
=18
REACTOR
C6H6+4.5O2C4H2O3+2CO2+2H2O
Basis: Produce 3000tons maleic anhydride per year
We take 1000kg of benzene
Its a batch process. Working days is 250days/yr
Feed
C6H6
1000kg
Theo. O2
(144/78)*1000
1846.15kg
1846.15+(1846.15*200/100)
5538.45kg
5538*(79/21)
20835.12kg
(144/78)*977
1803.6923kg
=
=
(98/78)*977
1227.512kg
Exp. O2
N2 in the air
97.7% conversion
Reacted O2
Product
C4H2O3 formed
21
Unreacted C6H6
=
=
1000-977
23kg
Unreacted O2
5538.45-1803.69
3734.755kg
(88/78)*977
1102.25kg
(36/78)*977
450.92kg
20835.12kg
CO2 formed
H2O formed
Unreacted N2
Air
O2-5538.45Kg
N2-20835.12Kg
REACTOR
C6H6-1000kg
C4H2O3-1227.512Kg/hr
CO2-1102.25Kg
H2O-450.92Kg
O2-3734.75Kg
ABSORBER
99% of the Maleic anhydride is absorbed into Dibutyl phthalate
22
C4H2O3-1227.51Kg/hr
CO2-1102.25Kg
O2-3734.75Kg
C6H6-23Kg
C4H2O31215.23Kg
Dibutyl
phthalate896 Kg
Dibutyl phthalate-4Kg
CO2-1102.25Kg
O2-3734.75Kg
C6H6-23Kg
DISTILLATION COLUMN
Separation of maleic anhydride and dibutyl phthalate
C4H2O3-1215.23Kg
Dibutyl phthalate896Kg
DISTILLATION COLUMN
C4H2O3-1202Kg
99%
Dibuty phthalate-6Kg
Recycle
Dibuty phthalate-890Kg
C4H2O3 -13.23Kg
23
ENERGY BALANCE
24
ENERGY BALANCE
VAPORISER
Q C6H6
10000.240910 (283-273)
240910 cal
2.40910 k cal
HEATER
Reference Temperature = 0C
Heat associated with reactants
Q C6H6
Qair
10000.240910(283-273)
240910 cal
2.40910 k cal
26373.57140.240810(313-273)
254030.2310 cal
254.0310 k cal
QN2
QO2
10000.605710(873-273)
36342010 cal
363.4210 k cal
3157927.2610 cal
3157.927310 k cal
5538.4510/32273.15873.15(8.27+0.000258T-187700/T)dT
792435.2310 cal
792.435210 k cal
Heat change
= Qpdt Hreac
25
(3157.9273+792.4352+363.42-2.409-254.03) 10
4057.3510 k cal
REACTOR
Reference Temperature = 25C
C6H6 + 4.5 O2 C4H2O3+ CO2 + H2O
Standard heat of reaction
HR = Hf Pdt Hf reac
= [-94.052+2 (-68.3164)+(-4062)]-
[0+6.9152]
= -4299.602 k cal
Heat associated with reactants
QC6H6
10000.605710(873.15-298.15)
348277.510 cal
348.277510 k cal
Q O2
5538.4510/32298.15873.15 (8.27+0.000258T-187700/T)dT
4427557.210 cal
4427.557210 k cal
Heat associated with products
Q C4H2O3
=
1227.512810/98298.15873.15 (93760+188.9T)d
35124.9610 cal
351.524910 k cal
= 1102.2510/44298.15873.15(10.34+0.00274T-195500/T)dT
Q CO2
=
161238.761410 cal
161.238710 k
cal
26
Q H 2O
450.9210/18298.15873.15(8.22+0.22015T+0.00000134T)dT
1982726.22410 cal
1982.72610 k cal
Heat Required =
Qpdt hreac + HR
(2495.4898-4775.8347- 4299.602)10
-6579.946910 k cal
Water
mCpT
318.15
(8.22+0.22015T+0.00000134T)dT
m
=
=
3974730 kg
3974.730 tonnes
REBOILER
INPUT
Q DBP
896/278 100.192
616.04T+2.2101T)dT
8753982.39410 cal
27
475.15
(461790373.15
8753.98210 k cal
OUTPUT
Q DBP
616.04T+2.2101T)dT
= 36350930.310 cal
= 36350.930310 k cal
HEAT CHANGE
OUTPUT INPUT
27596.9510 k cal
CONDENSER
MALEIC ANHYDRIDE
WATER
475.15
(8.22+0.22015T+0.00000134T)dT
m = 1058909 kg
= 1058.91 tonnes
28
DESIGN
29
Design
Reactor
Spherical catalyst particle diameter =
0.03m
1600khg/m3
0.0873kg/m3
As/Ap
(6Vp/)2/3
Vp
1.41310-5m3
-fluidization, mf
(0.071/)1/3
mf
0.414
Sphericity,
Remf
dphmfg/
(33.722+0.0408Ar)1/2-33.72
Archimedes number
Ar
dp3g(s-g)/ 2
0.033.0879(1600-.0879)9.81/8.52
5.1510-4
5.40610-7m/s
Residence time
1000/.0879
3.16m/sec
V/v0
3.476/3016
1.1sec
r2H
6D3/4
3.476
6D3/4
13.904
6D3
30
D3
13.904 / 6
0.9m
6D
60.9
5.4m
Design datas:
Diameter of reactor
0.9m
Height of reactor
5.4m
[Reference:9]
31
5.40610-7m/s
32
Distillation column
Maleic anhydride
1251-23/98
12.4 moles
896/278
3.22moles
3.22+12.4
15.262moles
0.793
1202/98
12.265moles
6/278
0.0216moles
xD
0.998
xB
0.04
xF
0.793
xD
0.998
xB
0.04
Dibutyl phthalate
Total moles
xF
Distillate
Maleic anhydride
Dibutyl phthalate
33
0
.019
.0721
.0966
.1661
.2337
.2608
.3273
.3965
.5079
.5189
.5732
.6763
.7472
.8943
0
.17
.3891
.4375
.5089
.5445
.558
.5826
.6122
.6584
.6599
.6856
.7485
.7815
.8951
= 1.3675m/s
Bubbling area
v/uc
1404kg/sec
1.404/2.1227
3
0.5372m /sec
0.5372/1.3675
2
0.3928m
Bubbling area
0.3928/0.7
0.5611m2
D2/4
0.5611
[(40.5611)/ ]1/2
0.8453m
85cm
Bubbling area
C.S.A of column
/0.7
34
0.998/(R+1)
0.998/(3+1)
0.2495
13-1
12
Assuming efficiency
70%
12/0.7
17
40cm = 0.4m
7.6m
Design Data:
Diameter of distillation column
0 .85m
7.6m
17
[Reference:7]
35
DISTILLATION COLUMN
VAPOUR
LQUID
WATER OUT
WATER IN
OVERHEAD
PUMP
PRODUCT
FEED
LIQUID
REBOILER
STEAM
CONDENSATE
VAPOUR
BOTTOM PRODUCT
36
37
PRESSURE CONTROL
Pressure control will be necessary for most systems handling vapor or gas. The
method of control depends on the nature of the process.
FLOW CONTROL
38
Flow control is usually with inventory control in a storage tank or othe r equipment.
There must be a reservoir to take up the changes in flow rate.
To provide flow control on a compression or pump running at a fixed speed and
supplying a near constant volume output, a by-pass would be used.
HEAT EXCHANGERS
Here, the temperature can be controlled by varying the flow of the cooling or heating
medium. If the exchange is between two process stream s whose flows are fixed, bypass control will have to be used.
CONDENSOR CONTROL
Temperature control is unlikely to be effective, unless the liquid stream is subcooled. Pressure control is often used, or control can be based on the outlet coolant
temperature.
REACTOR CONTROL
The schemes used for reactor control depend on the process and type of reactor. If
a online analyzer is available and the reactor dynamics are suitable, the product
composition can be monitored continuously and the reactor conditions and feed flows
controlled automatically to maintain the desired product composition and yield. More
often, the operation is the final link in the control loop, adjusting the controller set
points to maintain the product within specification, based on periodic laboratory
analyzer.
Regulating the flow of the heating or cooling medium will normally control
reactor temperature. Pressure is usually held constant. Material balance control will be
necessary to maintain the correct flow of reactants to the reactor and the flow of
product and unreacted materials from the reactor .
39
40
41
Any organization has a legal and moral obligation to safeguard the health and welfare
of its employees and the general public. The term loss prevention is an insurance
term, the loss being the financial loss caused by an accident. These losses will not
only be the cost of replacing damaged plant and third party claims ,but also the loss of
earnings from lost sales opportunities.
All manufacturing processes are to some extent hazardous, but in chemical process
are additional, special , hazards associated with the chemicals used and the process
condition. the designer must be aware of these hazards, and ensure , through the
application of sound engineering practice that the risks are reduced to acceptable
levels.
Safety and loss prevention in process design can be considered under the broad
headings
1)
2)
3)
4)
The duty of designer to select a process that is inherently safe whenever it is practical
and economical, to do so. However, most chemical manufacturing processes are, to
greater or lesser extent, inherently safe and dangerous situations can develop if the
process deviates from the design values.
The term engineered safety covers the provision in the design of control systems ,
alarms trips , pressure relief devices , automatic shutdown systems, duplication of key
equipment services , fire fighting equipment, sprinkler systems and blast wall to
contain any fire or explosion.
HEALTH EFFECTS
Probable rout The ACGIH threshold limit value in air for maleic anhydride is 0.25
ppm and the OSHA permissible exposure level (PEL) is also 0.25 ppm. Maleic
42
43
44
The location of the plant has a crucial effect on the profitability of a project, and the
scope for future expansion. The principal factors to be considered are:
3. Transport
Transport of raw materials, finished products and labor to and from the plant also
plays a key role in selecting the plant site.
4. Availability of labor
Labor will be need for the construction and operation of any plant. Skilled
construction will usually be brought in from outside the site area, but there should be
an adequate pool of unskilled labors available locally; and labors suitable to operate
the plant.
5. Utilities
Chemical processes invariably require large quantities of water for cooling and
general process use, and the plant must be located near a source of water of suitable
quality and quantity. Rivers, wells, lakes, sea etc can be used as sources of water .
46
6. Environmental impact
All industrial processes produce waste products, and full consideration must be
given to the difficulties and cost of their disposal. The disposal of toxic and harmful
effluents will be covered by local regulations and it is essential that these regulations
must be met.
7. Climate
Adverse climatic conditions at a site will increase costs. Buildings should be provide
with the necessary facilities.
8. Political and strategic considerations
Capital grants, tax concessions and other inducements are often given by
governments to direct new investment to preferred locations; such areas of high
unemployment. The availability of such grants can be overriding consideration in site
selection.
PROCESSING AREA
Processing area also known as plant area is the main part of the plant where the actual
production takes place. There are two ways of laying out the processing area
1) Grouped layout
2) Flow line layout
GROUPED LAYOUT
Grouped layout places all similar pieces of equipment adjacent. This provides for ease
of operation and switching from one unit to another. This is suitable for large plants.
STORAGE HOUSE
47
The main stage areas placed between the loading and unloading facilities and
the process they serve. The amount of space required for storage is determined from
how much is to be stored in what size containers. In raw material storage, liquids are
stored in bulk containers. Solids on the other hand are frequently stored in smaller
containers or in a pile on the ground.
UTILITIES
The word Utilities is now generally used for ancillary services needed in
the operation of any production process. These services will normally be supplied
from central site facilities and will include:
1. Electricity
2. Steam for process heating
3. Cooling water
4. Water for general uses
5. Inert gas supplies
FIRE STATION
Fire station should be located adjacent to the plant area, so that in case of
fire or emergency, the service can be put into action.
MEDICAL FACILITIES
Medical facilities should be provided with at least basic facilities giving
first aid to the injured workers. Provision must be made for the environmentally
acceptable disposal of effluent.
48
49
PROCESS ECONOMICS
50
ECONOMIC DATA
Equipment Costs
The numbers following the attribute are the minimum and maximum values for
that attribute. For a piece of equipment with a lower attribute value, use the minimum
attribute value to compute the cost. For a piece of equipment with a larger attribute
value, extrapolation is possible, but inaccurate. To err on the side of caution, you
should use the price for multiple, identical smaller pieces of equipment.
Pumps
Heat Exchangers
Compressors
Compressor Drive
Turbine
Fired Heater
51
Vertical Vessel
Horizontal Vessel
#)/20)0.25
for control valve use Rs1000 (nominal pipe diameter, in)0.8(1+(sch #)/20)0.25
UTILITY COSTS
Low-Pressure Steam (618 kPa saturated)
Rs272.3/1000 kg
Medium-Pressure Steam (1135 kPa saturated)
Rs287.7/1000 kg
High-Pressure Steam (4237 kPa saturated)
Rs344.05/1000 kg
Natural Gas (446 kPa, 25C)
Rs210/GJ
52
Rs175/GJ
Electricity
Rs2.1/kWh
Cooling Water
Rs12.39/GJ
Available at 516 kPa and 30C
Return pressure 308 kPa
Return temperature is no more than 15C above the inlet temperature
Rs155.05/GJ
Refrigerated Water
Available at 516 kPa and 10C
Return pressure 308 kPa
Return temperature is no higher than 20C
Rs35/1000 kg
Deionized Water
Available at 5 bar and 30C
Waste Treatment of Off-Gas
credit
Refrigeration
Rs276.15/GJ
Wastewater Treatment
Rs1960/1000 m3
53
compressors, vessels,
(absolute) 10 - 20 atm, PF = 0.6
cost
20 - 40 atm, PF = 3.0
40 - 50 atm, PR = 5.0
50 - 100 atm, PF = 10
Carbon Steel MF = 0.0
Stainless SteelMF = 4.0
Chemical
Price/Cost, Rs/kg
Dibutyl phthalate
60.2
Benzene
15.75
Maleic Anhydride
32.55
ECONOMIC ANALYSIS
When evaluating alternative cases, the equivalent annual operating cost
(EAOC) objective function should be used. The EAOC is defined as
EAOC = -(product value - feed cost utility costs waste treatment cost - capital cost
annuity)
A negative EAOC means there is a profit. It is desirable to minimize the EAOC; i.e.,
a large negative EAOC is very desirable.
The capital cost annuity is an annual cost (like a car payment) associated with
the one-time, fixed cost of plant construction.
The capital cost annuity is defined as follows:
54
S.No
Equipment
1
2
3
4
Reactor
Compressor
Heat Exchangers
Distillation
column
Absorber
Condenser
Storage tanks
Vessel
5
6
7
8
Cost of single
Equipment(in lakhs)
20
10
15
15
Number
1
1
2
1
Overall cost(In
lakhs)
20
10
30
15
15
10
12
10
1
1
4
1
15
10
48
10
i (1 + i ) n
(1 + i ) n 1
where FCI is the installed cost of all equipment; i is the interest rate (take i = 0.15)
and n is the plant life for accounting purposes (take n = 10).
When evaluating alternative cases, the following relationship should be used:
gross profit = value of products cost of raw materials
TEC
158lakhs
TEC[1+f1+f2+..f9]
Cost factor(c.f)
.4
.6
.15
.2
.1
.15
.1
.05
.4
158[1+.4+.6+.+.4]
497.7lakhs
55
.2
.05
.1
= PPC [1+f10+f11+f12]
= 497.7[1+.2+.05+.1]
= 671.895lakhs
= 671.895.05
= 33.59lakhs
= FCC+WC
= 705.4898lakhs
Operating labor
POSITION
Managing Director
General Manager
Deputy General
Manager
Senior Engineer
Junior Manager
R&D Staff
Lab Staff
Maintenance Staff
Formen
Operators
Unskilled Workers
NUMBER
1
2
4
SALARY(lakhs)
4.5
3.2
2.75
OVERALLSALARY(lakhs)
4.5
6.4
11.0
10
15
8
8
20
8
30
20
2.5
1.75
1.0
0.5
0.4
0.5
0.4
0.2
25.0
26.25
8.0
4.0
8.0
4.0
12.0
4.0
330.96lakhs
56
Variable cost(VC)
Raw material:
Benzene requirement/yr
10000250
2500000kg
Cost/kg of benzene
Rs15.75
Units of electricity
4500uits/day
Rs2.1
Steam requirement
(5% of raw materials)
19.68750lakhs
4.331250lakhs
1134+4.331250
117.48lakhs
FC+VC
330.96+1219.05
448.441lakhs
1.1 times of PC
1.1448.441
493.2851lakhs
Rs32.55
12020250
3005000Kg
maleic anhydride
Rs32.55
978.1275lakhs
Gross profit
production cost
=
978.1275-493.2851
57
484.8424lakhs
Depreciation(R)
Using Sinking Fund Method for calculating depreciation,
=
(V-Vs) (i/(1+i)n-1)
Vs
14.82lakhs
R
Where
Net profit
Net profit is defined as the expected annual return on investment after deducting
depreciation and taxes. Tax rate is assumed to be 45%
Net profit
251.84332lakhs
[Reference :6]
58
CONCLUSIONS
59
CONCLUSIONS
The Maleic Anhydride technology, through benzene route, which Indian
entrepreneurs opted for, in 70's, was appropriate, till early 80's. Because of the health
hazards associated with untreated benzene vapors, rising cost of benzene and its
demand in detergent alkylate, caprolactum, etc., attention, in developed countries, was
focused on alternate feed stock. Butane emerged the winner, because of, low cost and
easy availability, besides, being less hazardous to health. India has vast reserves of
natural gas, the utilization of which is poor, because of lack of infrastructural
development, so far C3/C4 fraction has-been earmarked for domestic fuel only, which
is a less profitable use, vis--vis, raw material for Maleic Anhydride.The demand of
Maleic Anhydride has been sluggish due to high cost of raw material and various
taxes on different end products. Installations of benzene recovery system, in the
existing manufacturing units, are lacking. Development of further applications of MA,
or, value added product growth, specially, with respect to usage of polyester resin
based products, appears insignificant, in India, going by the usage, of Maleic
Anhydride , in developed countries. Some research, on benzene oxidation, and, also,
for development of catalyst, on a limited scale, was undertaken by two National
Institutes, without much fruitful result. Enough capabilities exist, within the country,
with respect to fabrication of critical equipments, e.g., reactor, submersible pumps,
distillation column internals, etc., for Maleic Anhydride Plants. There is no evidence
to show that, on-line optimization, was done, for the existing plants. None of units is
having any benzene recovery system. Maleic Anhydride units in India are working,
outside the explosive range, with low benzene/O2 (air) ratio, with, consequent, higher
utilities cost, bigger reactor size for a, comparatively, less through-put. No attempt has
been made to manufacture Maleic Anhydride catalyst, though V2O5 based catalyst has
been developed and successfully used for other chemical processes.
60
REFERENCES
61
REFERENCES
1. Robert H.Perry:
Perrys Chemical Engineers Hand Book 5th and 6th edition.
2. Kirk and Othmer,
Encyclopedia of Chemical Technology Vol.13.2nd edition.
3. Robert Ewald Treybal
Mass Transfer operations
Mc Graw Hill Publications 2000
4.
M V Joshi, V V Mahajani
Process Equipment Design
Mac Millan Publications 2003
62