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Page 1: Final Review polystyrene

1. INTRODUCTION

Styrene, C6H5CH = CH2, is an unsaturated aromatic monomer, which

polymerizes to give polystyrene. Though, it was discovered way backin 1786, its

commercial production and applications were developed in the nineteen thirties. Post world

war period witnessed a boom instyrene demand due to its application in the manufacture of

synthetic rubber. This led to a dramatic increase in styrene capacity. Since then demand

and capacity have grown continuously.Polystyrene is manufactured by the addition

polymerization of styrene monomer unit. Dow Chemical is the world's largest producer

with a total capacity of 1.8 million metric tonne in the USA, Canada, and Europe.

Polystyrene is a versatile thermoplastic available in a wide range of

formulations, from crystal and impact grades to highly specializedresins for foam

moulding and extrusion, and resins that offer ignition -retardant properties.The wide range

in physical properties and relative ease of processing, makes polystyrene an extremely

attractivematerial, capable of competing favorably with more expensive resins in a number

of demanding applications.

Polystyrene: Indian Industry ScenarioPolystyrene is a first generation plastic. Its major advantages of cost, low density

and easy mouldability over the conventional materials have made it quite a success.

Consumption increased from 19,700 MT in 1984-85 to about 42,600 MT in 1990-91

registering a Cumulative Average Rate of Growth (CARG) of about 19%.

There are only two manufacturers of polystyrene in India. They are:

1. Polychem Ltd, Bombay

2. Hindustan Polymers (now, LG Polymers Pvt. Ltd), Visakhapatnam

(A unit of McDowell & Co. Ltd)

These two companies together, have catered to approximately 60% of the country's

needs of polystyrene in the Seventh Plan. Imports of PS have increased over six fold in the

Seventh Plan, from a mere 3700 T in 1984-85 to about 23,000 T in 1989-90 and 19,000 in

1990-91. (1990-91 registered low consumption because of the Gulf War). The major

sectors in India which consume general purpose PS & HIPS are the refrigerator sector,

consumer electronic goods (including audio and video cassettes), packaging, the

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Page 2: Final Review polystyrene

automotive sector and household articles and miscellaneous uses which includes :

novelties, stationery items, toys, ball pens, beads, toothbrushes, building materials and

sanitary wares, structural foam, crystal ware, wall clocks and the defence sector. EPS

production in the country in 1990-91 was close to 3500 T with LG polymers producing

1300 T and the balance being produced by BASF Ltd.

Demand Projections:The table below summarizes the demand projections for PS in the various sectors upto the

year 2000 A.D.

Table 1: Projected Demand for Polystyrene upto 1999-2000

Sector

(year)

Refrigerator

s

Consumer

electronic

Cassette

s

Packaging Others Total

(tonne)

1990-91 6000 9600 14100 4600 8000 42300

1994-95 9500 15100 29200 9500 16600 79900

1999-

2000

14000 22200 47100 19200 33400 135900

Polystyrene Supply Scenario:The table below gives the expected indigenous supply of PS upto 2000 A.D.

Table 2: Polystyrene Indigenous Supply Scenario

Year Polychem McDowe

ll

Suprem

e

Reliance Total

(tonne)

1994-95 14,400 19,800 24,000 _ 58,000

1995-96 24,000 24,000 30,000 _ 78,000

1996-97 30,000 30,000 36,000 24,000 120,000

1997-98 36,000 36,000 36,000 30,000 138,000

1998-99 36,000 36,000 36,000 36,000 144,000

1999-2000 36,000 36,000 36,000 36,000 144,000

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Demand Supply Gap:The demand supply gap up to the year 2000 A.D. has been worked out as follows:

Table 3: Polystyrene: Estimated Demand - Supply Gap

Year Demand Indigenous

supply

Demand – supply

gap/excess()

1991-92 42,300 34,200 8,100

1994-95 79,900 58,200 21,700

1999-2000 135,900 144,000 8,100

Technology Selection by Indian Companies:The table below summarizes the technology selection by the Indian manufacturers.

Table 4: Technology Selection by Indian Companies

S.no Company’s name Collaborator Type Remarks

1. Polychem Ltd

Polychem Ltd

DOW chemical,

USA

Huntsman

chemical corpn.

USA

Technical

and

finance

Collaboration

expired

Collaboration for

their new PS

capacity of 40000

TPA

2. LG polymers

LG polymers

BX-plastic, UK

Atochem,

france

Technical

Technical

Collaboration

was for the

existing plant

Expansion of PS

capacity to 40000

TPA

3. Reliance industries Hunstan

chemical corpn.

Technical New capacity of

40,000 TPA

4. Supreme

petrochemicals

Hunstan

chemical corpn

Technical New capacity of

40,000 TPA

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Polystyrene: International ScenarioGlobal consumption of Polystyrene has been increasing at a steady rate of

approximately 5% p.a. Consumption, which stood at 6.6 million tons in 1985 has increased

to about 8.5 million tons in 1990. However, there was only a marginal rise in consumption

between 1990 and 1991, with the developed countries showing a slight decrease.

Both General Purpose Polystyrene and High Impact Polystyrene have had an equal

share in the total consumption of Polystyrene. Manufacturing capacity has increased by 2

million tons from 8.5 million in 1985 to about 10.5 million in 1990. The below figure

shows the world consumption of polystyrene in 2010.

Taiwan Canada

Rep. of korea mexico Oceania

South America

Japan china

others

Africa Western Europe

Central Europe

United states

Figure 1: World Consumption of Polystyrene in 2010

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2. PROPERTIES AND USES OF POLYSTYRENE

2.1. Physical Properties:

Table 5: Physical Properties of Polystyrene

Appearance White crystalline solid

Density 0.96-1.04

Molecular formula (C8H8)n

Melting point ~ 240 0C

Thermal conductivity 0.033 W/Mk

Refractive index 1.6

2.2.Processing Properties:Flow properties may be the most important properties of polystyrene processes.

There are two widely accepted industry methods for the measurement of processing

properties. These include the melt flow index and the solution viscosity.

The melt flow index is measured by ASTM method as a measure of the melt

viscosity at 200 0C and a 5kg load. The melt flow index of polystyrene is generally

controlled by adjustment of the molecular weight of the material and by the addition of

such lubricants as mineral oil. Polystyrenes are commercially produced with melt flow

ranges of less than 1 to greater than 50, although the most widely available gradesgenerally

have melt flows between 2.0 and 20g per 10min.

Solution viscosity is another method for measuring the molecular structure of the

polystyrene. Solution viscosity can be measured as an 8% solution in toluene and increases

with increasing molecular weight.Polystyrene is a non-Newtonian fluid with viscoelastic

properties. The viscosity of polystyrene melts or solutions is defined as the ratio of shear

stress to shear rate. Generally, as the molecular weight of the polymer is increased or

mineral oil is decreased, melt viscosity increases.

2.3. Mechanical Properties:Crystal polystyrenes have very low impact strengths of less than 0.5ft-lb.

Commercially available impact polystyrene grades can be obtained with values of 1.0 - 4.0

ft-lb. Generally, polystyrenes are not produced with greater than 15% total rubber because

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of polymerization processing constraints. Nevertheless,impact properties can be increased

substantially without additional rubber by the proper control of rubber particle size,

percentage of grafting, cross-linking, and percentage of gel.

Tensile and flexural properties are also important representation of the strength of

polystyrenes. Increasing the rubber modification of polystyrene generally leads to lower

tensile strength, crystal grades being stiff and brittle. Tensile strength is also decreased by

the addition of lubricants, such as mineral oil. Flexural strengths for polystyrenes can be

obtained from 5000 to 18000psi and are also decreased by the addition of rubber and other

additives to the polystyrene. Elongations can be obtained from 1% for crystal polystyrene

to 100% for some impact polystyrene grades.

2.4. Thermal Properties:Annealed heat distortion is one popular method for measuring the resistance to

deformation under heat for polystyrenes. The heat distortion temperature is decreased by

the addition of rubber, mineral oil, or other additives to polystyrene. The glass transition

temperature for unmodified polystyrene is 373 K, and the glass transition temperatures for

poly butadienes are 161-205 K, subject to the cis, trans and vinyl content.

2.5. Chemical Properties:Solvent crazing of polystyrene is a commercially important phenomenon. High

impact polystyrenes are susceptible to solvent crazing at the interface between the rubber

particles and the polystyrene phase. The resistance of polystyrene to this crazing is referred

to as environmental stress crack resistance (ESCR).

For food-packaging applications, such as butter tubs and delicate containers,

polystyrene with high ESCR properties are desirable. Increasing the percentage of gel,

percentage grafting, and rubber particle size can increase stress crack resistance.

Residual levels of low molecular weight materials are also important topolystyrene

performance. Some of the chemical impurities in the polystyrene are styrene monomer and

ethyl benzene solvent. Residual levels of styrene below 200 ppm and ethyl benzene levels

below 30 ppm are obtainable for very specialized applications.

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2.6. USES:1. Extruded foam sheet of polystyrene can be thermoformed into such parts as egg cartons

or carryout food containers. These are also used in crafts and model building, in particular

architectural models.

2. Crystal polystyrene materials have excellent thermal and electrical properties which

make them useful as low cost insulating materials,envelope windows, cap layers for glossy

sheet, orthermoforming into food packaging applications.

3. Another type of polystyrene foam is that produced from expandable polystyrenebeads.

These beads can be molded to produce hot drink cups, ice chests, disposable trays, plates,

bowls, calm shells(food packaging) and cushioned or foampackaging.

4. Also, the expandable beads can be molded in very large blocks that can then be cut into

sheets for thermal insulation. These are supplied as compound with blowing agent and

other additives.

5. High Impact Polystyrene is often specified for low strength structural applications when

impact resistance, machineability and low cost are required.

6.Natural HIPS is complaint for use in food processing applications. Stero regular poly

butadiene elastomers are used for impact modifications. It can be processed easily by all

conventional thermoplastic fabricating techniques which include film, sheet and profile

extrusion, thermoforming, injection moulding, injection blow moulding and structural

blow moulding.

7. Optical property of polystyrene is used in manufacture of unbreakable glasses for

gauges, windows and lenses, as well as in countless specialties and novelties and also for

edge lighting for the edge lighting of indicators and dials.

8. Solid or liquid pigments and dies color high impact and crystal polystyrenes. This can be

accomplished in both extrusion and injection moulding processes. These colorants are

added and mixed during the melting stage of both the processes. Also, polystyrene parts

are amenable to high quality printing. Labels can beprinted directly on the polystyrene part

to produce attractive containers.

9.Polystyrenes are also used in furniture, packaging, appliances, automobiles,construction,

radios, televisions, toys, house ware items, and luggage.

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3. LITERATURE SURVEY OF DIFFERENT PROCESSES

The different methods available for styrene polymerization are:

3.1. Bulk polymerization.

3.2. Solution polymerization.

3.3. Emulsion polymerization.

3.4. Suspension polymerization.

3.1. Bulk Polymerization:Solution (bulk) polymerization is commonly referred to as mass polymerization in

the industry. The vast majority of all polystyrene produced today is produced via this

technology. The common solvents used in this process are the styrene monomer itself and

ethyl benzene. The two types of mass polymerization are batch and continuous, of which

continuous mass is by far the most popular.

Bulk addition polymerization is a homogeneous process which uses an organic

initiator. The higher the temperature, the lower the molecular weight of the polymer

produced. At higher temperatures, the initiator decomposes to form radicals at a faster rate,

then for a given amount of monomer with more radicals present more polymer chains will

be started (initiated), and the resulting polymers will have a lower molecular weight.

We can have continuous polymerization at very low temperatures if we use light toconvert

the initiator molecules to radicals (which will start the polymerization).

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Figure 2: Polystyrene Manufacture by Bulk Polymerization

3.2. Solution Polymerization

Solution polymerization is a method of industrial polymerization. In this procedure,

monomer is dissolved in a non-reactive solvent that contains a catalyst. The reaction results

in a polymer which is also soluble in the chosen solvent(either water or an organic

solvent). E.g: polystyrene in toluenemonomer is soluble and the polymer is insoluble in the

diluent, acrylonitrile in chloroform. Heat released by the reaction is absorbed by the

solvent, and so the reaction rate is reduced. Once the maximum or desired conversion is

reached, excess solvent has to be removed in order to obtain the pure polymer.

3.3.Emulsion Polymerization:Emulsion polymerization is generally used for polymerization of styrene with other

monomers or polymers. It is not a generally commercially accepted method of producing

crystal polystyrene or high impactpolystyrene(HIPS). Emulsion polymerization is carried

out similarly to suspension polymerization except that the monomer droplets are

microscopic in size. Emulsion polymerization is also a heterogeneous polymerization with

water as the continuous phase. In this system, however, monomer droplets are dispersed in

water using surfactants or emulsifying agents, and a stable emulsion is produced.

Emulsion systems are characterized by substantially smaller particle sizes than

suspension polymerizations, with particles in the range of 0.05 to 0.2 μm. Additionally, a

water soluble initiator rather than monomer-soluble initiator is employed, and very

different kinetic features are observed. The end product of an emulsion polymerization is a

stablelatex, an emulsion of polymer in water.

3.4. Suspension Polymerization:This is also called pearl polymerization. It has proved highly efficient for large

scale production of polymers of high average molecular weight. By variation of the

polymerization condition it is possible to produce a range of polymers with different

properties and processing characteristics so that a number of grades are offered by the

manufacturers to meet the differing requirements of the conversion process and the final

product.

There are many different ways of making polystyrene using suspension process.

Most producers use a batch process, although there is no technical reasons why a

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continuous process could not work. In the suspension process a number of small styrene

drops 0.15-0.50mm in diameter are suspended in water. The reaction occurs within these

drops. To aid in the formation of proper size drops a suspending agent is used, and to keep

them at that size a stabilizing agent is added. A catalyst is used to control the reaction rate.

Table 6: Polymerization Systems Comparison

Type of polymerization Advantages Disadvantages

Bulk Low impurity levels

No solvent removal

Thermal control difficult

Side reactions, “hot spots”

Thermal degradation

Explosion risk

Solution Thermal control

Easy mixing due to lower

viscosity

Improved initiation

efficiency

Difficult to remove solvent and

other ingredients

Cost of solvent recovery

Solvent environmental impact

Potential chain transfer to

solvent

Suspension Thermal control

Low viscosity throughout

reaction

High purity product

Simple polymer isolation

Agitation control

Particle size difficult to control

Possible contamination by

dispersing agents

polymer may require washing

and drying.

Emulsion Thermal control

Low viscosity throughout

reaction.

Latex may be directly

usable.

High MW at high rates

with relatively narrower

MWD.

Small particle size

product.

Difficult to remove surfactants,

emulsifiers, coagulants.

Residuals may degrade polymer

properties.

Polymer may require washing

and drying.

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4. SELECTION OF THE PROCESS

Among the above 4 processes suspension polymerization offers considerable

advantages over the single phase techniques in so far that heat removal control is no longer

a problem and a high purity product is obtained, but there are disadvantages such as the

need to use a dispersing agent. Bulk polymerization process is generally used to produce

large amounts of expandable polystyrene and highly thermal control process. In solution

and emulsion processes solvent should be recovered and residues are formed which is not a

problem in suspension polymerization. Finally, based on the above considerations

suspension polymerization for the manufacture of polystyrene is selected.

It is used only in free radical type processes. The monomer is mechanically

dispersed in a media, usually water. There are cases where an organic media is used in

which neither the polymer nor the monomer are soluble in the organic media. The initiator

used can be water soluble or organic soluble (benzoyl peroxide, AIBN, or (NH4)2(SxO4)y).

Usually the initiator is organic soluble. There are two separate phases throughout the whole

process. The droplets must be kept far apart. This requires agitation: consistent, efficient,

andcontrolled. A suspending agent can be used. Polyvinyl alcoholdissolved in the

aqueousphase is a typical suspending agent. The rate of suspension polymerization is

similar to the rate of bulk polymerization, but the heat transfer is much better. Examples

include the polymerization of MMA, and vinyl chloride. The medium to monomer ratio is

10:1. Particle size is affect by the following four factors:

• Stirring rate

• Ratio of reactants

• Suspension agent

• Temperature

If the particle size gets to large, the particle will absorb too much heat. Particle size

may be 0.01 to 0.5 cm, or as low as 1 micron. A suspension agentis a material that gives a

surface activation that keeps droplets from become larger (droplets coming together to

form larger droplets is called coalescence). Suspension polymerization is similar to bulk

polymerization, and it could be considered "bulk polymerization within a droplet."

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5. PROCESS DETAILS

Suspension polymerization is a batch system popular for special grades of

polystyrene. It can be used to produce either crystal or high impact grades. In impact

production, the styrene and rubber solution is bulk polymerized beyond phase inversion

and is then suspended in water to create oil in water suspension utilizing soaps and

suspending agents. The suspended droplets are then polymerized to completion, utilizing

initiator and a staged heating profile. The water phase is used as a heat sink and heat

transfer medium to a temperature controlled jacket. For the production of crystal

polystyrene the styrene monomer itself is suspended and polymerized via the same

mechanism.

Reaction conditions:The reaction mixture consists of two phases, a liquid matrix and monomer droplets.

The monomer and initiator are insoluble in the liquid phase, so they form drops within the

liquid matrix. A suspension agent is usually added to stabilize the monomer droplets and

hinder monomer drops from coming together. The reaction mixture usually has a volume

ratio of monomer to liquid phase of 0.1 to 0.5. The liquid phase acts as a heat transfer

agent, enabling high rates of polymerization with little change in the temperature of the

polymerizing solution.

The reactions are usually done in a stirred tank reactor that continuously mixes the

solution using turbulent pressure or viscous shear forces. The stirring action helps to keep

the monomer droplets separated and creates a more uniform suspension, which leads to a

more narrow size distribution of the final polymer beads. The polymerization is usually

carried to completion.The kinetics of the polymerization within an individual bead are

similar to those of typical radical polymerization.

Particle properties:Suspension polymerization is divided into two main types, depending on the

morphology of the particles that result. In bead polymerization, the polymer is soluble in

its monomer and the result is a smooth, translucent bead. In powder polymerization, the

polymer is not soluble in its monomer and the resultant bead will be porous and irregular.

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The morphology of the polymer can be changed by adding a monomer diluent, an

inert liquid that is insoluble with the liquid matrix. The diluentschanges the solubility of

the polymer in the monomer and gives a measure of control over the porosity of the

resulting polymer.

The polymer beads that result can range in size from 100 nm to 5 mm. The size is

controlled by the stirring speed, the volume fraction of monomer, the concentration and

identity of the stabilizers used, and the viscosities of the different components. The

following equation derived empirically summarizes some of these interactions:

d = k (Dv*R*vm*Є) /(Ds*N*vt*Cs)

where, d is the average particle size, k includes parameters related to the reaction

vessel design, Dv is the reaction vessel diameter, Ds is the diameter of the stirrer, R is the

volume ratio of the monomer to the liquid matrix, N is the stirring speed, νm and νl are the

viscosity of the monomer phase and liquid matrix respectively, ε is the interfacial tension

of the two phases, and Cs is the concentration of stabilizer. The most common way to

control the particle size is to change the stirring speed.

The requirements of polymerization are:

a. Initiator

b. Suspending agent

c. Stabilizing agent

d. Catalyst

e. Polymerization temperature

a. Initiators: The initiators generally used are benzoyl peroxide and t-butyl hydro

peroxide.

b. Suspending agent: To aid in the formation of the proper size drops a suspending agent

is added. Some typical suspending agents are methylcellulose, ethyl cellulose and

polyacrylic acids. Their concentration in the suspension is between 0.01-0.5% of monomer

charged.

c. Stabilizing agent: To keep the drops at proper size, a stabilizing agent is added. The

stabilizing agents are often insoluble inorganic such as calcium carbonate, calcium

phosphates or bentonite clay. They are present in small amount than the suspending agents.

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d. Catalyst: A catalyst is used to control the reaction rate. The catalysts are usually

peroxides. The most common ones are benzoyl, diacetyl, lauroyl, caproyl and tert-butyl.

Their concentration varies from 0.1-0.5% of the monomer charged.The ratio of monomer

to dispersing medium is between 10 and 40%.

e. Polymerization temperature:Polymerization of styrene occurs at temperature range of

90-950C.

Process description: The main manufacturing route to styrene is the direct catalytic dehydrogenation of

ethyl benzene:

CH3 CH2 catalyst CH2 CH + H2

Ethyl benzene styrene

The reaction shown above has a heat of reaction of -121 kJ/mol (endothermic).

The suspension method is carried out in large reactors equipped with agitators, the

styrene monomer being maintained in the aqueous phase as droplets with a diameter

varying between 0.4-1mm by use of a dispersing agent such as partially hydrolyzed

polyvinyl acetate, inorganic phosphates or magnesium silicates.

To reduce the cycle time of the reactors, the entering water and styrene will be

preheated. The temperatures of the input streams will be sent so as to obtain the desired

reaction temperature. The water entering the reactor will be heated to 950C. The bulk of the

styrene is to be heated to 850C before being charged. This is done in a vertical doublepipe

heat exchanger, which is directly above the reactor. To prevent the polymerizationfrom

occurring in the heat exchanger or piping system, there are to be no obstructions between

this heat exchanger and the reactor.

Nearly 65% of all styrene is used to produce polystyrene. The overall reaction

describing the styrene polymerization is:

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Page 15: Final Review polystyrene

initiator

X CH2 CH CH2 CH

X

Styrene Polystyrene

This reaction is carried out in an inert organic solvent environment, which provides

the reaction medium for this cationic polymerization reaction. The catalyst, rubber

stabilizer, and suspending agent are premixed in styrene and discharged by gravity into the

reactor. This mixture will not be preheated, since it might polymerize. Typical water to

monomer ratios is 1:1 to 3:1. A combination of two or moreinitiators is used with a

programmed reaction temperature to reduce the polymerization time to a minimum for a

given amount of residual styrene.

Purification Steps and Extrusion:If the water can be removed using physical separation processes, then the styrene

and the other impurities dissolved in it will also be discharged. A centrifuge with a

washing step will be used to do this. The material leaving the centrifuge has 1-5%

water.The final purification step is drying.

The polystyrene leaving this unit must meet the specifications set (0.03% water).

Then it is passed through a devolatization extruder to remove the volatile residues and to

convert the polymer into pellets.It was assumed that 3% of polystyrene would be removed

from the process in airvying, drying, centrifuging, transferring, or as bad as bad product.

At least 95% of that which is lost in processing must be intercepted before it leaves the

plant. Most of it can be removed and sold as off-grade material. This waste is split among

the various streams leaving the processing area.

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Figure 3: Flow sheet of suspension polymerization

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Reactor

6. MATERIAL BALANCE

Basis:Amount of polystyrene produced per day = 250 TPD

= 250*103/24

= 10416.67Kg/hr

Assumptions:

1. It will be assumed that 99.8% of the styrene is reacted and this can be accomplished by

using an average of the temperatures and cycle time given.

2. Temperature of reaction = 90-95C

3. Cycle time of reactor=5.5hrs.

Reactor:Dodecyl benzene benzoyl peroxide +

sulphonate miscellaneous

styrene(1.032 kg/kg PS)

polystyrene

water + tricalcium

phosphate styrene

water miscellaneous

Figure 4: Material Balance over reactor

Input to the reactor:Styrene = 1.032 kg styrene/kg polystyrene

= 1.032*10416.67

= 10750kg

Water = 2.0 kg water/kg polystyrene

= 2.0*10416.67

= 20833.34kg.

Tricalcium phosphate = 0.005 kg tricalcium phosphate/kg polystyrene

= 0.005*10416.67

= 52.083kg.

Dodecyl benzene sulphonate = 0.00006 kg dodecyl benzene sulphonate/kg PS

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Page 18: Final Review polystyrene

= 0.00006*10416.67

= 0.625kg.

Benzoyl peroxide = 0.0025 kg benzoyl peroxide/kg polystyrene

= 0.0025*10416.67

= 26.042kg.

Miscellaneous = 0.004

= 0.004*10416.67

= 41.67kg.

Total input to reactor = 31703.75kg.

Output from the rector:Polystyrene =1.030 kg polystyrene / kg of polystyrene

= 1.030*10416.67

= 10729.17kg.

Styrene = 0.002 kg styrene/kg polystyrene

= 0.002*10416.67

= 20.83kg

Water = 2.0 kg water/kg polystyrene

= 2.0*10416.67

= 20833.34kg.

Miscellaneous = 0.01156 kg /kg polystyrene

= 0.01156*10416.67

= 120.41 kg.

Total output from reactor = 31703.75 kg.

Table 7: Reactor Material Balance

Components input(kg/kg PS) output(kg/ks PS)

Styrene 1.032 0.002

Polystyrene - 1.030

Water 2 2

tri calcium phosphate 0.005 -

dodecyl benzene sulphonate 0.00006 -

benzoyl peroxide 0.0025 -

Miscellaneous 0.004 -

Total 3.04356 3.04356

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Wash tank

Wash tank: output from the reactor

3.04356 kg/kg of PS

2.0 kg of water/kg of PS

0.004 kg of HCl/kg of PS

1.030 polystyrene (unit ratio)

0.002 styrene (unit ratio)

4.0 water

0.0156 miscellaneous

Figure 5: Material Balance over Wash tank

Input to wash tank:Output from reactor = 3.04356*10416.67

= 31703.76kg.

Water =2.0 kg water/ kg polystyrene

= 2.0*10416.67

=20833.34kg.

Hydrochloric acid = 0.004 kg HCl/ kg polystyrene

= 0.004*10416.67

= 41.67 kg.

Total input to wash tank =31703.75 + 20833.34 + 41.67

= 52578.75kg.

Output from wash tank:Polystyrene = 1.030 kg polystyrene/ kg polystyrene desired

=1.030*10416.67

= 10729.17kg

Styrene = 0.002 kg styrene/kg polystyrene

= 0.002*10416.67

= 20.83kg.

Water = 4.0 kg water/ kg polystyrene

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Centrifuge

= 4.0*10416.67

= 41666.68kg.

Miscellaneous = 0.01556 kg/kg of polystyrene

= 0.0156*10416.67

= 162.08kg

Total output from wash tank = 10729.17+ 20.83+41666.68+162.08

= 52578.75 kg

Table 8: Wash Tank Material Balance

Components input(kg/kg PS) output(kg/kg PS)

Polystyrene 1.030 1.030

Styrene 0.002 0.002

Water 4 4

Miscellaneous 0.01156 0.01556

HCl 0.004 -

Total 5.04756 5.04756

Centrifuge:Output from wash tank

0.01 kg of PS/kg of PS

0.002 kg of styrene/kg of PS

1.0 kg of water/kg of PS 4.95 kg of H2O/kg of PS

0.01546 misc./kg of PS

(desired)

1.02 kg of PS / kg of PS

0.05 kg of water/ kg of PS

0.0001 kg of misc./kg of PS

Figure 6: Material Balance over Centrifuge

Input to the centrifuge:Output from wash tank = 52578.75 kg

Water =1.0 kg water/kg polystyrene

=10416.67 kg water.

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Output from centrifuge:The output from centrifuge comprises of two layers. One is the desired and theother is bad

product.

Desired product composition:

Polystyrene = 1.02 kg polystyrene/kg of desired polystyrene

= 1.02*10416.67

= 10625kg

Water = 0.05 kg water/ kg polystyrene

= 0.05*10416.67

= 520.83kg

Miscellaneous = 0.0001 kg/ kg polystyrene

= 0.0001*10416.67

=1.041667 kg

Undesired product composition:

Polystyrene = 0.01kg polystyrene/kg polystyrene

= 0.01*10416.67

=104.1667 kg

Styrene = 0.002 kg styrene /kg polystyrene

= 0.002*10416.67

=20.83kg

Water = 4.95 kg water / kg polystyrene

= 4.95*10416.67 = 51562.51kg

Miscellaneous = 0.01546 kg/ kg polystyrene

=0.0155*10416.67

=161.042 kg.

Table 9: Centrifuge Material Balance

components input(kg/kg

PS)

Desiredoutput(kg/kgPS) undesired output(kg/kg

PS)

polystyrene 1.030 1.02 0.01

styrene 0.002 - 0.002

water 5 0.05 4.95

miscellaneous 0.01556 0.0001 0.01546

total 6.04756 1.0701 4.97746

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Dryer

Dryer:Air (1.3486 kg/ kg PS) + outputfrom centrifuge

0.015 kg of PS/kg of PS 0.005 kg of PS/ kg of PS

(bad product) 1.39851 kg of moist air/ kg of PS

(desired product)

1.0 kg of PS/kg of PS

0.0001 kg of water/ kg of PS

Figure 7: Material Balance over Dryer

Input to the dryer:Output from the centrifuge = 10625 + 520.83 + 1.041667

= 11146.87kg

Air = 1.3486 kg / kg PS

= 1.3486*10416.67

= 14048 kg

Output from the dryer:Output from dryer comprises of three parts

1. Desired polystyrene with composition:

Polystyrene =1.0 kg/kg polystyrene

= 10416.67 kg of polystyrene

Water = 0.0001 kg/kg polystyrene

= 0.0001*10416.67

= 1.041667kg

2. Undesired Product with Polystyrene = 0.005 kg/kg polystyrene

= 0.005*10416.67

= 52.083kg

Moist air = 1.39851 kg/kg polystyrene

= 1.39851*10416.67

= 14567.82 kg

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Extruder

3. Bad product obtained has a composition of polystyrene

= 0.015 kg/kg polystyrene

= 0.015*10416.67

= 156.25kg

Table 10: Dryer Material Balance

components input(kg/kg PS) desired output(kg/kg PS) undesired output(kg/kg PS)

polystyrene 1.02 1.0 0.02

water 0.05 0.0001 -

miscellaneous 0.0001 -

Air 1.348 -

moist air - - 1.398

Total 2.4181 1.0001 1.418

Extruder:

output from dryer

1.0 kg of Polystyrene

0.0001 kg water/ kg PS

Figure 8: Material Balance over Extruder

Input to extruder =output from dryer = 10416.67 + 1.0417667

= 10417.712 kg

Output from extruder = 10417.712 kg

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7. ENERGY BALANCE

Assumptions:1. Assume 2kg of styrene are to be used to carry each kg of additive into the reactor.

2. Steam at 150 psi is used as heating medium.

3. The reaction is taking place in a batch reactor.

4. Assume heat losses of about 10%.

5. Cycle time of the reactor = 5.5 hrs.

6. Assume 9 reactors were used.

Styrene heat exchanger:Temperatures Inlet Outlet

Styrene 30oC 93oC

The additive feed tank must be large enough to handle all additive plus a carrier solution of

styrene. The amount of dodecyl benzene sulphonate, tricalcium phosphate and benzoyl

peroxide used per batch are:

= (0.005 + 0.00006 + 2 * 0.0025) * 10416.67 * 5.5 / 9

=64.039 kg.

For 2 kg of styrene used = 64.039 * 2 (assumption 1)

= 128.078kg.

When GPPS is made, all but 128.078kg of styrene are heated to 93C. For theother

products less is used. Qs = msCpsTs

where, Qs is the rate of heat transfer

ms is the flow rate of styrene through exchanger

= ((1.032 kg styrene/kg PS)*10416.67 kg PS *5.5hrs/9 – 128.078 kg styrene) / (5min/60)

= 77296.4 kg/hr.

Cps= heat capacity of styrene = 0.43 Btu/ lboF = 1.799 kJ/ kgoC

Ts= temperature difference of styrene entering at 30oC and leaving exchanger at 93oC

= 93 – 30 = 63oC

Qs = 77296.4*1.799*63

= 8760.54*103kJ/hr.

At 150 psi, Ts=182oC. (assumption)

= latent heat of vaporization = 1995.98kJ/hr.

Qs =msCpsTs = m *

Therefore, mass flow rate of steam required, m = 8760.54*103/1995.98

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= 4389.09kg/hr.

Air heat exchanger:Temperatures Inlet Outlet

air 30oC 150oC

The air is to be heated to 150C using 150psi steam.

The amount of energy required = Qa= ma. Cp. T = m

Where,

ma= flow rate of air used in dryer

= 14048 kg/hr

Cp= heat capacity of air entering and leaving the exchanger

= 1.0468 kJ/kg C

T = temperature difference of air entering at 30oC and leaving the exchanger at 150oC

= 150 – 30 = 120C.

= latent heat of vaporization = 1995.98kJ/hr.

Qa= 14048*1.0468*120

= 1.76465*106kJ/hr.

Amount of steam required, m = Qa / = (1.76465*106) / 1995.98

= 884.1kg/hr.

Reactor cooling system:From equation (2), (8) of reactor design,

Diameter, D = 2.479m

Average energy removed per hour= 77.989*103 D3kJ/hr.

= 77.989*103*(2.479)3.

= 118.813*104 kJ/hr

= 330.036kJ/s.

Inlet temperature of cooling water = 30C.

Outlet temperature of cooling water = 68C.

Specific heat of cooling water, Cp=4.187kJ/kg oC

Let mw be the amount of cooling water required to remove the heat.

Heat released in the reaction = heat gained by the cooling water

Q = mw. Cp. T.

mw *4.187*(68-30) = 330.036 kJ/s

mw = 2.0743 kg/s in each reactor.

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Therefore amount of water required in total for 9 reactors = 2.0743*9

=18.668 kg/s.

Dryer:Temperatures Inlet Outlet

Polystyrene 30C. 80C.

Air 150C. 85C.

Specific heat of polystyrene, Capps=1.337kJ/kg oC

Heat required to raise polystyrene product entering the dryer to discharge temperature,

= m* Cpps*T

= 10625kg/hr*1.337*103*(80-30)/3600s

= 1.97300*105 W

Specific heat of water, Cpw = 4.187 kJ/kg oC

Heat required for removing water entering the dryer,

= m*Cpw*T

= 520.83kg/hr*4.187*103*(80-30)/3600s

= 0.302877*105W.

Therefore total heat required,

= 7.1028*105+ 1.09035*105W.

= 8.19315*105W.

The amount of air required is determined by the amount of energy 150C. Airmust supply

to remove the moisture from the polystyrene.

m = Qt/( Cp.T).

Where, Cp= heat capacity of air = 0.237 Btu/ lboC = 0.9923 J/kg oC.

T = difference in air temperature entering and leaving dryer, C.

Qt = heat transferred in dryer =8.20803*105W.

m = mass flow rate of air.

m = (8.19315*105) /(0.9923*(150-85))*3600

= 12702.656kg/hr.

The amount of air is adequate. Add 10% to account for possible heat losses. (assumption 4)

Therefore mass flow rate = 1.1* 12702.656

= 13972.922 kg/hr.

8. SPECIFIC EQUIPMENT DESIGN

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Assumptions:1. Heat of the reaction = 300 BTU/lb.

2. Assume 90% of the reactor is full and height of the reactor is 2 times of its

diameter

3. Density of the mixture is 1/3 of the way between water and styrene.

4. Assume maximum reaction rate is nearly twice the average rate.

5. Assume cycle time for GPPS is 5.5 hrs and it takes 0.5 hrs for MPPS and 1.0 hrs

for HIPS longer than GPPS and time taken for charge and discharge is 1hr and

0.5hr to initiate the reaction.

6. The reaction is taking place in a batch reactor.

Process design of the reactor:The polymerization of styrene is an exothermic reaction. The amount of energy

released at any time is dependent on the volume of the reactor, and the rate of removal of

that heat is dependent on the surface area. Unless the heat is removed, the temperature will

rise and the reaction rate will increase. The result will be an uncontrolled reaction that not

only may ruin the batch but could also damage the reactor and might cause fire or

explosion to occur. Therefore there is a maximum size of the reactor for each set of

reaction condition which will be calculated. The maximum rate of heat production will be

first calculated.

The heat of polymerization = 300 Btu/ lb (assumption 1)

= 300*1.055/0.4536

= 697.79 kJ/kg.

Mass fraction of the styrene = 1.032/(1.032+2)

= 1.032/3.032

= 0.34037

The weight of styrene in the reactor = ρ*V* mass fraction of styrene (1)

Where, ρ = Density of mixture (assumption 4)

= 929.086 kg/m3

V = volume of reactor=area*length = πD2/4 *L

Where, D = diameter of reactor

L = length of reactor.

Therefore equation (1) becomes,

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Weight of styrene in the reactor = 0.9*929.086*0.34037*π*D2 / 4*(2*D) (assumption 2)

= 447.063*D3 kg.

Therefore the energy released by polymerization

= Weight of styrene in reactor*heat of polymerization

= 447.063*D3 * 697.79

= 311.956*103*D3 kJ

All this energy must be removed as it is formed.

The cycle time for GPPS = 5.5 hrs (assumption 5)

If the time taken for charge and discharge = 1 hr

And time taken to initiate the reaction = 0.5hr

Then all the energy released must be removed in 5.5-1-0.5 = 4.0hr.

Therefore average energy produced per hour = 311.956*103*D3 / 4

= 77.989*103D3 kJ/hr. (2)

However, the reaction rate is not uniform. The maximum reaction rate must be known to

calculate the area needed for heat exchange.

The maximum heat produced per hour = 2* average energy produced/hr.(assumption 4)

= 2*77.989*103*D3 kJ/hr

= 155.978*103*D3*103 J/3600 s

= 43327.22 D3 J/s (3)

The rate of heat removed,

Q = U.A.ΔTο (4)

Where, U = overall heat transfer coefficient.

A = area of heat transfer.

ΔTο = average temperature driving force between coolant and suspension.

Since 95% of the time, the air temperature is below 30οC. It will be assumed that inlet

cooling water temperature never exceeds 30οC.

The reaction temperature = 93οC.

Assume the maximum cooling water outlet temperature rise is5οC.

Therefore outlet temperature of cooling water =35οC

Therefore the average temperature of cooling water =(30+35)/2 = 32.5οC.

ΔTο= 93-32.5 = 60.5οC.

Overall heat transfer coefficient at 60.5oC = 50Btu/hr.ft2K =283.9 W/m2K

The area of heat transfer is thearea covered by the suspension. This can be estimatedto be

the bottom surface are + 90% of the sides. ( assumption 2)

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Area, A = 0.9πDL + πD2 /4

= 6.44D2

Substituting values of A, ΔTο and U in equation (3), we get,

Q = 283.9*6.44D2 *60.5 (5)

Comparing equation (3) and equation (5), we get,

43327.22*D3 = 283.9*6.44D2 *60.5

D = 283.9*6.44*60.5/ 43327.22

= 2.553 m.

As, L = 2D (assumption 2)

= 2*2.553

= 5.106 m.

And, V = πD2L/ 4

= π*(2.553)2*5.106/4

= 26.138 m3

= 6904.93 gal.

In ‘encyclopedia of polymer technology and science’, the following statement appears:

“In a suspension polymerization of styrene in a 5000 gal reactor, the lowest coolant

temperature required is 120°F (49° C)”.

Hence now the average coolant temperature is taken as 49°C instead of 32.5°C.

Outlet temperature of cooling water, T = 68°C.

And, average temperature = (68 + 30)/2 = 49°C.

ΔTο= 93 - 49 = 44°C.

Also ‘U’ at ΔTο=44oC is 60 BTU/ hr.ft2.°F =341.22 W/m2 K and a maximum reaction rate

of 1.8 times theaverage would be better estimates.

Taking maximum heat released per hour = 1.8 times average value.

(equation2,assumption 4)

= 1.8*77.989 *D3*106/ 3600

= 38994*D3 J/s (6)

Rate of heat removed Q =U.A.ΔTο

= 341.22*6.44*D2*44 (7)

Heat released in the reactor = heat gained by cooling water

From equations (6),(7)

38994*D3 = 60*5.687*6.44D2*44

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D = 341.22*6.44*44/38994 = 2.479m (8)

L = 2*D =2*2.479 = 4.96m

V = πD2L/ 4

= π*(2.479)2*4.96/4

= 23.94 m3

Equation (1) becomes

Amount of styrene produced per reactor per hour

= (0.9*ρ *V*mass fraction)/cycle time

= (0.9*929.086*23.94*0.34037)/5.5 (assumption 2,5)

= 1238.83 kg/hr.

Number of GPPS reactors required for 60% conversion is:

= (10416.67kg PS*1.032 kg styrene/kg PS* % of conversion)/amount of styrene

produced per reactor = (10416.67*1.032*0.6)/1238.83

= 5.206 rectors.

All the above calculations have been done using GPPS. It will be assumed that the same

conditions apply to MPPS and HIPS except that the reaction times are different. For

economic purpose, the same size reactor will be used for each product.

For MPPS the reaction takes 0.5hrs longer = 5.5+0.5 =6hrs.

For HIPS the reaction takes 1.0 hrs longer = 5.5+1 = 6.5 hrs.

Number of MPPS reactors required for 20% conversion = (5.206*0.2* 6)/(0.6*5.5)

= 1.893 reactors.

Number of HIPS reactors required for 20% conversion = (5.206*0.2*6.5)/(0.6*5.5)

= 2.05 reactors.

Therefore together we need 4 reactors for MPPS, HIPS and 5 reactors for GPPS making a

total of 9reactors needed. A 10th reactor will be installed as a spare. This will allow full

production to continue if cleaning out the reactors becomes more of a problem

thanexpected.

Mechanical design:Data from literature:

Design pressure for the reactor = 220psi = 16.47 kg/cm2.

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Design pressure for jacket = 75psi = 6.27 kg/cm2.

Permissible stress of reactor = 950kg/cm2.

Shell internal diameter = 2.486m.

Agitator horse power for 5000gal = 50hp

Diameter of agitator = 1035mm.

Speed = 200rpm.

Agitator blades (flat) = 6

Width of blade =75mm.

Thickness of blades =8mm.

Shaft material – commercial cold rolled steel.

Permissible shear stress in shaft = 550kg/cm2.

Elastic limit in tension = 2460kg/cm2.

Modulus of elasticity =19.5*105kg/cm2.

Permissible stresses for key (carbon steel)

Shear = 650kg/cm2.

Crushing = 1300kg/cm2.

Stuffing box (carbon steel)

Permissible stress = 950kg/cm2.

Studs and bolts (hot rolled carbon steel)

Permissible stress = 587kg/cm2.

Joint efficiency = 0.85.

Poisons ratio = 0.3.

9. MATERIALS OF CONSTRUCTION

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The choice of construction material for a polymerization reactor will depend on a

variety of factors, most importantly the specific polymerization to be performed. Stainless

steel construction offers a lot more options and has many things to consider. The particular

alloy of stainless steel to be used involves a balance of economics, corrosion engineering,

and pressure vessel mechanical design. Process heat transfer issues may also enter the

decision. Type 304 has a higher allowable stress than 316 but a somewhat narrower

spectrum of corrosion resistance. It is also a little less expensive material. So it may be

indicated for plants that require large, higher pressure reactors. However if there is a

component of the polymerization that is corrosive to 304 then 316 might be preferred.

Material Properties:

AC408 gives consideration to maximum replacement volume, and maximum size

and density of synthetic particles that will be recognized in the evaluation report. AC408

requires synthetic particle properties, including maximum diameter and gradation, bulk

density, and water absorption to be tested in accordance with ASTM C 136, ASTM C 29

and ASTM C 128, respectively. A series of tests is also required by AC408 to determine

density and compressive strength of concrete that is to be evaluated under AC408.

Concrete compressive strength measurement is to be in accordance with ASTM C 39.

ASTM C 567 and ASTM C 138 are used to measure the equilibrium concrete density and

unit weight, respectively. These properties are measured and reported to be used for

flexural strength, splitting tensile strength and modulus of elasticity calculations.

Mechanical Properties:

As required by AC408, concrete flexural strength is to be determined using ASTM

C78, and average test results are to be equal to or higher than the value obtained from

7.5√fc, where fc is the measured compressive strength of the concrete in accordance with

ASTM C 39.

Fire-resistance and Combustibility:

AC408 also contains two optional tests: noncombustible building material

evaluation by testing in accordance with ASTM E 136 to show that concrete with

lightweight synthetic particles can be classified as noncombustible material and fire-

resistance-rated construction tests conducted in accordance with ASTM E 119 to determine

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the fire-resistance ratings of assemblies with concrete containing the light weight synthetic

particles in the concrete mixture.

Acceptance Criteria Statements:

If a product demonstrates through tests that it satisfies all requirements of AC408,

an evaluation report is issued verifying that the product can be used as an alternative to

building code-specified materials.

1) Evaluation reports must state the maximum replacement amount of the light weight

synthetic particles that was utilized during the qualification tests, along with particle

density and maximum water absorption values.

2) To maintain product consistency, AC408 requires third-party follow-up inspections

by an approved inspection agency for the manufacture of the light weight synthetic

particles. This is required so that the manufacturer will continue to produce the same

product used during the qualification tests.

3) For structural design purposes, concrete containing light weight synthetic particles

must be considered as structural lightweight concrete. This requires use of ACI 318

parameters and design coefficients specified for structural light weight concrete. Because

the density of concrete produced using light weight synthetic particles as aggregate

replacement may vary, implementing light weight concrete coefficients and parameters is

considered to be a conservative approach for design of reduced-weight concrete with

synthetic light weight particles.

4) In addition to the items of ASTM C 94, the delivery ticket from the ready- mix plant

must include the type and amount of lightweight synthetic particles added to the concrete

mixture.

5) Because of the presence of compressible EPS beads in the concrete mixture, the creep

of the concrete was of concern. Therefore, for applications where computed deflections

contain long-term deflections due to sustained loads, creep effects based on creep test

results must be considered in design, which must be submitted to the code official for

approval.

6) Chloride content of EPS beads was of concern for corrosion of reinforcement.

10. HEALTH, SAFETY AND ENVIRONMENTAL ASPECTS

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Waste products:Polystyrene manufacture is a relatively clean process. Small volumes of liquidand

gaseous wastes are generated and these are treated within the plants. Waste polystyrene

generated during production is reprocessed or sent to a recycler. Polystyrene manufacture

is a relatively clean process. Small volumes of liquid and gaseous wastes are generated and

these are treated within the plants. Waste polystyrene generated during production is

reprocessed or sent to a recycler. This is a Most Energy-EfficientPackaging Material.

Polystyrene is Safe, Hygienic Polystyrene and the Enemy ofBacteria.

Ease of disposal:According to the U.S. Environmental Protection Agency (EPA) in the 1999 update

of the"Characterization of Municipal Solid Waste in the U.S." report, less than one

percent(about 0.6 percent) of solid waste disposed of in the U.S. is polystyrene packaging -

including both food service packaging (cups, plates, bowls, trays, clam shells, meat trays,

egg cartons, yogurt and cottage cheese containers, and cutlery) and protective

packaging(shaped end pieces used to ship electronic goods and loose fill "peanuts").

The disposal of polystyrene is managed safely and effectively through the

integrated system advocated by the U.S. EPA, which includes: Source Reduction, Reuse,

Recycling, Waste-to-Energy Recovery, and Landfilling.

Polystyrene safe to use in contact with food:For more than 40 years, polystyrene has been in wide spread use as a hygienic

material for protecting and preserving food. In fact, one-reason polystyrene single use food

containers are so widely used in hospitals and other sensitive environment is that they are

significantly more hygienic than the alternatives. Polystyrene does not harbor bacteria,

which is a major concern among health specialists.

A recent American study shows that 1 in 7 reusable dishes harbor a level of

bacteria which exceeds US health standards. In contrast, no disposable food service items

exceeded the standards.

Foam Polystyrene – Presence of CFC’s:

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Extruded foam polystyrene produced in for meat, chicken and vegetable trays and

take away food containers, does not use CFC blowing agents. Producers converted

awayfrom CFC's in 1989 and now operate on recycled carbon dioxide or hydrocarbon

gases.Expandable or bead polystyrene (EPS) such as in produce boxes has always used a

hydrocarbon blowing agent.

Reuse:Reuse, the practice of utilizing polystyrene products in the same form, is important

notonly because it delays the final disposal of a product, but also because it reduces

themanufacture and purchase of new products. As a result, reuse prevents waste. Nearly

30percent of polystyrene loose fill (sometimes called "peanuts" because of its shape)

isused again, making it one of the most commonly reused packaging materials in

someretail locations. For mailing services, the reuse rate of loose fill is as high as 50

percent.

The successful application of reused loose fill polystyrene reduced the demand for

virgin polystyrene by 25 percent in 1997 alone and, to this day, continues to directly

reduce waste.Other packaging and disposables commonly reused by the polystyrene

industry include:pallets, insulated shipping boxes, test tube trays, auto part trays, ice chests

and coolers.

Recycling:The recycling of polystyrene protective packaging and non-packaging polystyrene

materials, (such as audio/visual cassettes and agricultural nursery trays/containers) has

increased dramatically during the last decade and there has been a decrease in the amount

of polystyrene food service packaging recycled during this period. Non-food

servicepackaging is not contaminated with food and other wastes as is food service

polystyrene packaging, and therefore is more cost-effective to recycle. Presently, food

service polystyrene packaging is generally not recycled because it is not economically

sustainable. It is important to note that because of unfavorable economics, no other post

consumer food service disposable material, including paper and paperboard, is recycled in

a measurable way.

Before 1988, there was essentially no recovery of post-consumer polystyrene for

recycling, but as of 2000, just twelve years later, more than 397 million pounds of

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polystyrene packaging were recycled. A portion of this material came from durable

polystyrene products such as coat hangers, compact disc "jewel cases," single-use cameras

and agricultural nursery trays.

Some companies that make protective packaging are collecting it back forrecycling

through the Alliance of Foam Packaging Recyclers. In addition, some makes of loose fill

"peanuts" have set up a network of collection sites for reuse and recycling of their

polystyrene products. Products that have incorporated recycled-content polystyrene

include: foam eggcartons, lunch trays, transport packaging, audio and videocassette cases,

office supplies and building materials.

Waste-to-Energy Recovery:In many overseas countries polystyrene is recycled through incineration of

municipal waste for energy recovery. The burning of polystyrene is no more hazardous

than combustion of many natural organic materials.

Polystyrene consists solely of carbonand hydrogen. When combustion is complete,

water and carbon dioxide are given off, leaving trace levels of ash, the same combustion

products as from paper or wood. While some polystyrene in medical an municipal wastes

is currently incinerated in Australia, the energy recovery option has not yet been

implemented.

When incinerated, polystyrene produces energy, which compares favorably

withcoal and oil. Because of its high fuel value, polystyrene in properly designed

incineratorshelps to burn wet garbage more efficiently, and maintain the high burning

temperaturesnecessary for safe combustion.The incineration of plastics can also generate

energy and this potential is alreadybeing harnessed in some overseas countries, particularly

in Western Europe, The UnitedStated and Japan.

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Land filling:While recycling and reuse continue to grow in popularity, most of the waste in this

country still goes to landfills. People assume the waste inside a land fill biodegrades. But

the fact is that very little - not paper, not polystyrene, not even food waste - degrades in a

meaningful way.

Polystyrene is effectively and safely disposed of in landfills. Modern landfills are

designed to protect the environment from the liquids and gases produced during the very

slow breakdown by reducing the exposure of garbage to air, water and sunlight -conditions

needed for degradation. Therefore, by design, modern landfills greatly retardthe

degradation process to reduce the by-products that might otherwise contaminate

groundwater and the air.

Preventing Litter:The polystyrene industry cares about the environment. A widely held

misconception is that litter is a problem caused by specific materials themselves rather than

aberrant consumer behavior. The reality is that some people improperly dispose of

materials by littering. Littering is a matter of behavior, people who discard materials into

theenvironment usually do so because they don't think or don't care. Attributing the litter

issue to one particular packaging material does not solve the problem because another type

of packaging will take its place as litter unless behavior changes.

MSDS SHEETMSDS Name: Polystyrene

Chemical Family: Polymer.

Hazards Identification:Physical State

Appearance

Emergency Overview

Routes of Entry

Potential Acute Health

Solid

Pellets

Irritating vapors to respiratory system and eyes may

form when polymer is processed at high temperatures.

Molten or heated material in skin contact can cause

severe burns.

For Hot Material: skin contact, eye contact, and

inhalation.

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Effects:

Eyes

Skin

Inhalation

Ingestion

First Aid Measures:

Eye Contact

Skin Contact

Inhalation

Ingestion

Fire Fighting Measures:

Flammability of the Product

Auto-ignition Temperature

Flash Points

Flammable Limits

Products of Combustion

Explosion Hazards in

Presence of Various

Substances

Dust may cause mechanical irritation to eye.

Heated Polymer: Eye contact can cause serious

thermal burns.

Vapours formed when polymer is heated may be

irritating to the eye.

No known acute effects of this product resulting from

skin contact at room temperature.

Negligible at room temperature. Nuisance dusts can be

irritating to the upper respiratory tract.

Irritating vapors may form when the polymer is

processed at high temperatures.

No effects are expected for ingestion of small amounts.

May be a choking hazard.

Rinse with water for a few minutes. Seek medical

attention if necessary.

Polymer: NO known effect on skin contact, rinse with

water for few minutes.

Heated Polymer:For serious burns from heated

polymer, get medical attention. In case of skin contact,

immediately immerse in or flush with clean, cold water.

Allow the victim to rest in a well-ventilated area.

No First Aid procedures are needed.

May be combustible at high temperature.

440°C (824°F)

>200°C (>392°F)

Not available

Carbon oxides (CO, CO2) and soot.

Risks of explosion of the product in presence of

mechanical impact: Not expected.

Risks of explosion of the product in presence of static

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Fire Fighting Media and

Instructions

Protective Clothing (Fire)

Special Remarks on

FireHazards

Special Remarks on

Explosion Hazards

Handling and Storage:

Handling

discharge: Possible.

Risk of explosion from dust accumulation of this

product is possible.

SMALL FIRE: Dry chemical extinguisher (ABC or

AB). Use water spray or fog.

LARGE FIRE: Use water spray or fog. Do not use

water jet.

May re-ignite itself after fire is extinguished.

Wear MSHA/NIOSH approved self-contained

breathing apparatus or equivalent and full protective

gear.

Fire may produce irritating gases and dense smoke.

Flowing material may produce static discharge, igniting

dust accumulations.

Processing or material handling equipment may

generate dust of sufficiently small particlesize, that

when suspended in air may be explosive.

Avoid Temperatures of 600°F (316°C) or above.

Handling of plastic may form nuisance dust. Protect

personnel.

Pneumatic material handling and processing equipment

may generate dust of sufficiently small particle size

that, when suspended in air, may be explosive. Dust

accumulations should be controlled through a

comprehensive dust control program that includes, but

is not limited to,source capture, inspection and repair of

leaking equipment, routine housekeeping and employee

training in hazards.

When handled in bulk quantities, this product and its

associated packaging may present a crushing hazard

due to the large masses involved, possibly resulting in

severe injury or death.

Keep container dry. Keep in a cool place. Ground all

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Storage

Personal Protection:

Eyes

Body

Respiratory

Hands

Feet

Stability and Reactivity:

Stability and Reactivity

Incompatibility with

Various Substances

Hazardous Decomposition

Products

Hazardous

Polymerization

equipment containing material. Keepcontainer tightly

closed. Keep in a cool, well-ventilated place.

Combustible materials shouldbe stored away from

extreme heat and away from strong oxidizing agents.

Safety glasses

Coveralls.

Ventilation is normally required when handling this

product at high temperatures. Wear appropriate

respirator when ventilation is inadequate.

Thermally insulated gloves required when handling hot

material.

Shoes.

The product is stable. Avoid Temperatures of 600°F

(316°C) or above.

Reactive with strong oxidizing agents.

Hazardous decomposition products are carbon

monoxide, carbon dioxide, dense smoke, and various

hydrocarbons. Exposure of polystyrene to extremely

high temperatures (600oF orhigher) may cause partial

decomposition. Chemicals that may be released include

styrenemonomer, benzene, and other hydrocarbons.

No.

11. PLANT LOCATION AND LAYOUT

Plant Location

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The geographical location of the plant can have a crucial effect on the profitability

of a project, and the scope for future expansion. Many factors must be considered when

selecting a suitable site, and of the plant on studying many factors Visakhapatnam in

Andhra Pradesh is selected as the best place. The principal factors to be considered are:

Marketing area.

Raw material supply.

Transport facilities.

Availability of labour.

Availability of utilities: water, fuel, power.

Availability of suitable land.

Environmental impact, and effluent disposal.

Local community considerations.

Climate.

Political strategic considerations.

Marketing Area

For materials that are produced in bulk quantities: such as cement, mineral acids

and fertilizers, where the cost of the product per ton is relatively low and the cost of

transport a significant fraction of the sales price, the plant should be located close to the

primary market. This consideration will be less important for low volume production, high-

priced products; such as pharmaceuticals. In an international market, there may be an

advantage to be gained by locating the plant within an area with preferential tariff.

Raw Materials

The availability and price of suitable raw materials will often determine the site

location. Plants producing bulk chemicals are best located close to the source of the major

raw material; where this is also close to the marketing area. Soda ash plant should be

located near the salt lakes or near sea, where sodium chloride is available abundantly.

Transport

The transport of materials and products to and from plant will be an over riding

consideration in site selection. If practicable, a site should be selected that is close at least

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two major forms of transport: road, rail, waterway or a seaport. Road transport is being

increasingly used, and is suitable for local distribution from a central warehouse. Rail

transport will be cheaper for the long-distance transport of bulk chemicals. Air transport is

convenient and efficient for the movement of personnel and essential equipment and

supplies, and the proximity of the site to a major airport should be considered.

Availability of Labor

Labor will be needed for construction of the plant and its operation. Skilled

construction workers will usually be brought in from outside the site, but there should be

an adequate pool of unskilled labor available locally and labor suitable for training to

operate the plant. Skilled trades men will be needed for plant maintenance. Local trade

union customs and restrictive practices will have to be considered when assessing the

availability and suitability of the labor for recruitment and training.

Utilities (services)

The word “utilities” is now generally used for the auxiliary services needed in the

operation of any production process. These services will normally be supplied from a

central facility and will include:

• Electricity - Power required for electrochemical processes, motors, lightings and general

use.

• Steam for process heating - The steams required for the process are generated in the tube

boilers using most economic fuel.

• Cooling water - Natural and forced draft cooling towers are generally used to provide the

cooling water required on site.

• Water for general use - The water required for the general purpose will be taken from

local water supplies like rivers, lakes and seas. Because of this reason all the plants located

on the banks of river.

• Dematerialized water - Dematerialized water, from which all the minerals have been

removed by ion-exchange is used where pure water is needed for the process use, in boiler

feed water.

• Refrigeration - Refrigeration is needed for the processes, which require temperatures

below that are provided by the cooling water.

• Inert-gas supplies.

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• Compressed air - In a polystyrene plant compressed air is one of the raw materials. It is

also needed for pneumatic controllers etc.

• Effluent disposal facilities - Facilities must be provided for the effective disposal of the

effluent without any public nuisance.

Environmental Impact and Effluent Disposal

All industrial processes produce waste products, and full consideration must be

given to the difficulties and coat of their disposal. The disposal of toxic and harmful

effluents will be covered by local regulations, and the appropriate authorities must be

consulted during the initial site survey to determine the standards that must be met.

Local Community Considerations

The proposed plant must fit in with and be acceptable to the local community. Full

consideration must be given to the safe location of the plant so that it does not impose a

significant additional risk to the community. Land (site considerations) sufficient suitable

land must be available for the proposed plant and future expansion. The land should be

ideally flat, well drained and have load-bearing characteristics. A full site evaluation

should be made to determine the need for piling or other foundations.

Climate

Adverse climatic conditions at site will increase costs. Abnormally low

temperatures will require the provision of additional insulation and special heating for

equipment and piping. Stronger locations will be needed at locations subject to high wind

loads or earthquakes.

Political and Strategic Considerations

Capital grants, tax concessions, and other inducements are often given by

governments to direct new investment to preferred locations; such as areas of high

unemployment. The availability of such grants can be the overriding consideration in site

selection.

Plant Lay Out

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The economic construction and efficient operation of a process unit will depend on

how well the plant and equipment specified on the process flow sheet is laid out. The

principal factors are considered are:

Economic considerations: construction and operating costs.

The process requirements.

Convenience of operation.

Convenience of maintenance.

Safety.

Future expansion.

Modular construction.

Costs

The cost of construction can be minimized by adopting a layout that gives the

shortest run of connecting pipe between equipment, and at least amount of structural steel

work. However, this will not necessarily be the best arrangement for operation and

maintenance.

Process Requirements

An example of the need to take into account process consideration is the need to

elevate the base of columns to provide the necessary net positive suction head to a pump or

the operating head for a thermo siphon reboiler.

Operations

Equipment that needs to have frequent attention should be located convenient to the

control room. Valves, sample points, and instruments should be located at convenient

positions and heights. Sufficient working space and headroom must be provided to allow

easy access to equipment.

Maintenance

Heat exchangers need to be sited so that the tube bundles can be easily with drawn

for cleaning and tube replacement. Vessels that require frequent replacement of catalyst or

packing should be located on the outsideof buildings. Equipment that requires dismantling

for maintenance, such as compressors and large pumps, should be places under cover.

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Safety

Blast walls may be needed to isolate potentially hazardous equipment, and confine

the effects of an explosion. At least two escape routes for operators must be provided from

each level in process buildings.

Plant expansion

Equipment should be located so that it can be conveniently tied in with any future

expansion of the process. Space should be left on pipe alleys for future needs, and service

pipes over-sized to allow for future requirements.

Modular construction

In recent years there has been a move to assemble sections of plant at the plant

manufacturer’s site. These modules will include the equipment, structural steel, piping and

instrumentation. The modules are then transported to the plant site, by road or sea.

The advantages of modular construction are:

Improved quality control.

Reduced construction cost.

Less need for skilled labour on site.

Some of the disadvantages are:

Higher design costs & more structural steel work.

More flanged constructions & possible problems with assembly, on site.

The Plant Layout Key Words1. Raw material Storage

2. Product Storage

3. Process Site

4. Laboratories

5. Workshop

6. Canteen & Change house

7. Fire Brigade

8. Central Control Room

9. Security office

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10. Administrative Building

11. Site for Expansion Project.

12. Effluent treatment plant

13. Power house

14. Emergency water storage

15. Plant utilities

A detailed plant layout is drawn and some general considerations that influenced the plans

follow:

1. Space was set aside for a whole new train.

2. The prevailing wind in the summer comes from the northwest and in the winter comes

from the west.

3. The blow down tank is located on the south side of the plant where winds will

notgenerally carry any spills over the plant.

4. The utilities and the waste treatment areas are located on the north side of theplant

where they will be upwind of the plant.

5. The styrene storage will be located on the south side of the plant 300ft from the river

and the dock. It will be 300ft from the processing area.

6. The warehouse and the bulk storage will be located on the west side, upwind from the

plant and styrene storage. They will be at least 250ft from reactor area.

7. The reactor and the feed preparation area will be on the east side of the plant 200ft from

the river.

8. The other processing areas will be between the reactor area and the warehouse. They

will be over 200ft from the reactor area.

Some specific considerations follow:

1. There must be enough headroom above the reactor to remove the agitator.

2. There must be enough room to remove the screw from the extruder.

3.Gravity feed is to be used for charging additives to the reactor, for discharging the

reactor to the hold tanks, and for feeding the dryer.

4. Each of the styrene storage tanks will have a dike around it that is capable of containing

the tank’s contents when it is full.

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Figure: 9 plant layout

12. COST ESTIMATION

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Calculation of fixed capital cost:The Chemical Engineering Plant cost Index (CEPI):

In 1969, CI1 = 119.0

In 2013, CI2 = 685.0

Let us assume that the plant is running for 325 days a year.

From literature, the capital cost for the proposed plant should range between $124 and

$253 per annual ton.

Let us take value of 1$ = Rs 50.

Let us take capital cost = $200 per annual ton.

i.e., C1= Rs 10000 per annual ton.

Total tones of polystyrene produced every year = 325 * 250

= 81250tones /year.

Therefore the capital cost for proposed plant in 1969 is = 81250*10000

= Rs.8.125*108

From, William's six-tenth rule,

CI1/ CI2= C1/C2

C2 = C1 * (CI2/CI1)

The fixed capital cost for the proposed plant in 2013 = 8.125*108*685/119

i.e., C2 = Rs 467.69*107

= Rs 467.69crores.

Estimation of Capital Investment Cost:

I. Direct Costs: material and labor involved in actual installation of

completefacility (70-90% of fixed-capital investment).

a. Equipment + installation + instrumentation + piping + electrical + insulation +

painting(50-60% of Fixed-capital investment).

1. Purchased equipment cost (PEC):(15-40% of Fixed-capital investment)

Consider purchased equipment cost = 30% of Fixed-capital investment

i.e., PEC = 30% of 467.69*107

= 0.30 * 467.69*107

= Rs. 140.31*107

2. Installation, including insulation and painting:(25-55% of purchased

equipment cost.)

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Consider the Installation cost = 35% of Purchased equipment cost

= 35% of 140.31*107

= 0.35 *140.31*107

= Rs.49.11*107

3. Instrumentation and controls, installed:(6-30% of Purchased equipment

cost.)

Consider the installation cost = 15% of Purchased equipment cost

= 15% of *140.31*107

= 0.15 *140.31*107

= Rs.21.05*107

4. Piping installed:(10-80% of Purchased equipment cost)

Consider the piping cost = 35% Purchased equipment cost

= 35% of Purchased equipment cost

= 0.35 *140.31*107

= Rs. 49.11*107

5. Electrical, installed:(10-40% of Purchased equipment cost)

Consider Electrical cost = 25% of Purchased equipment cost

= 25% of 140.31*107

= 0.25 *140.31*107

= Rs.35.0775*107

b. Buildings, process and Auxiliary: (10-70% of Purchased equipment cost)

Consider Buildings, process and auxiliary cost= 30% of PEC

= 30% of 140.31*107

= 0.30 *140.31*107

= Rs.42.093*107

c.Service facilities and yard improvements:(40-100% of Purchased equipment

cost)

Consider the cost of service facilities and yard improvement= 50% of PEC

= 50% of 140.31*107

= 0.50 *140.31*107

= Rs 70.155*107

d. Land:(1-2% of fixed capital investment or 4-8% of Purchased equipment cost)

Consider the cost of land = 6% PEC

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= 6% of 140.31*107

= 0.06 *140.31*107

= Rs. 8.42*107

Thus, Direct cost = Rs.415.325*107 ----- (88.80% of FCI)

II. Indirect costs: Expenses which are not directly involved with material and

labor of actual installation of complete facility (15-30% of Fixed-capital investment).

a. Engineering and Supervision:(5-30% of Fixed-capital investment)

Consider the cost of engineering and supervision = 10% of direct cost

= 10% of 415.325*107

= 0.1*415.325 *107

= Rs 41.5325*107

b. Construction Expense and Contractor’s fee: (6-30% of Fixed-capital

investment)

Consider the construction expense and contractor’s fee = 10% of Direct costs

= 10% of 415.325*107

= 0.1* 415.325 *107

= Rs 41.5325*107

c. Contingency:(5-15% of Fixed-capital investment)

Consider the contingency cost = 10% of Fixed-capital investment

= 10% of 415.325 *107

=Rs.41.5325*107

Thus, Indirect Costs = Rs. 124.5975*107 --- (26.64% of FCI)

III. Fixed Capital Investment:Fixed capital investment = Direct costs + Indirect costs

= (415.325 *107) + (124.5975*107)

i.e., Fixed capital investment = Rs. 539.92*107

IV. Working Capital:(10-20% of Fixed-capital investment)

Consider the Working Capital = 15% of Fixed-capital investment

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i.e., Working capital = 15% of 539.92*107

= 0.15 * 539.92*107

= Rs. 80.988*107

V. Total Capital Investment (TCI):Total capital investment = Fixed capital investment + Working capital

= (539.92*107) + (80.988*107)

i.e., Total capital investment = Rs. 620.908*107.

Estimation of Total Product cost:

I. Manufacturing Cost = Direct production cost + Fixed charges + Plant

overhead cost.

a. Fixed Charges:(10-20% total product cost)

i. Depreciation: (depends on life period, salvage value and method of calculation-about

13% of FCI for machinery and equipment and 2-3%for Building Value for Buildings).

Consider depreciation = 12%of FCI for machinery and equipment and 4%for building

Value for Buildings)

i.e., Depreciation = (0.12*140.31*107)+ (0.04*42.093*107)

= Rs. 18.521*107 (from straight line depreciation)

ii. Local Taxes: (1-4% of fixed capital investment)

Consider the local taxes = 3% of fixed capital investment

i.e., Local Taxes = 0.03*539.92*107

= Rs. 16.1976*107

iii. Insurances: (0.4-1% of fixed capital investment)

Consider the Insurance = 0.6% of fixed capital investment

i.e., Insurance = 0.006*539.92*107

= Rs. 3.24*107

iv. Rent: (8-12% of value of rented land and buildings)

Consider rent = 10% of value of rented land and buildings

= 10% of ((8.42*107) + (42.093*107))

= 0.10* ((8.42*107) + (42.093*107))

Rent = Rs. 50.513*107

Thus, Fixed Charges = Rs. 88.472*107

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b. Direct Production Cost: (about 60% of total product cost)

Now we have Fixed charges = 10-20% of total product charges – (given)

Consider the Fixed charges = 15% of total product cost

Total product charge = fixed charges/15%

Total product charge = 88.472*107/15%

Total product charge = 88.472*107/0.15

Total product charge (TPC) = Rs. 589.82*107

i. Raw Materials: (10-50% of total product cost)

Consider the cost of raw materials = 25% of total product cost

Raw material cost = 25% of 589.82*107

= 0.25*589.82*107

Raw material cost = Rs. 147.45*107

ii. Operating Labor (OL): (10-20% of total product cost)

Consider the cost of operating labor = 15% of total product cost

Operating labor cost = 15% of 589.82x107

= 0.15*589.82*107

Operating labor cost = Rs. 88.473*107

iii. Direct Supervisory and Clerical Labor (DS & CL): (10-25% of OL)

Consider the cost for Direct supervisory and clerical labor = 12% of OL

Direct supervisory and clerical labor cost = 12% of 88.473*107

= 0.12*88.473*107

Direct supervisory and clerical labor cost = Rs. 10.61676*107

iv. Utilities: (10-20% of total product cost)

Consider the cost of Utilities = 12% of total product cost

Utilities cost= 12% of 589.82*107

= 0.12*589.82*107

Utilities cost = Rs. 70.7784*107

v. Maintenance and repairs (M & R): (2-10% of fixed capital investment)

Consider the maintenance and repair cost = 5% of fixed capital investment

i.e., Maintenance and repair cost = 0.05*539.92*107

= Rs. 26.996*107

vi. Operating Supplies: (10-20% of M & R or 0.5-1% of FCI)

Consider the cost of Operating supplies = 15% of M & R

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i.e., Operating supplies cost = 15% of 26.996*107

= 0.15 *26.996*107

Operating supplies cost = Rs. 4.094*107

vii. Laboratory Charges: (10-20% of OL)

Consider the Laboratory charges = 15% of OL

i.e., Laboratory charges = 15% of 88.473*107

= 0.15*88.473*107

Laboratory charges = Rs. 13.271*107

viii. Patent and Royalties: (0-6% of total product cost)

Consider the cost of Patent and royalties = 4% of total product cost

i.e.,Patent and Royalties= 4% of 589.82*107

= 0.04*589.82*107

Patent and Royalties cost = Rs 23.593*107

Thus, Direct Production Cost = Rs. 385.272*107 ----- (65.32% of TPC)

c. Plant overhead Costs (50-70% of Operating labour, supervision, and

maintenance or5-15% of total product cost); includes for the following: general plant

up keep and over head, payroll overhead, packaging, medical services, safety and

protection, restaurants, recreation, salvage, laboratories, and storage facilities.

Consider the plant overhead cost = 60% of OL, DS & CL, and M & R

Plant overhead cost = 60% of ((88.473*107) + (10.61676*107) + (26.996*107))

Plant overhead cost = 0.60 * ((88.473*107) + (10.61676*107) + (26.996*107))

Plant overhead cost = Rs. 75.651*107

Thus, Manufacture cost = Direct production cost + Fixed charges + Plant overheadcosts.

Manufacture cost = (385.272*107) + (88.472*107) + (75.651*107)

Manufacture cost = Rs. 549.395*107

II. General Expenses = Administrative costs + distribution and selling costs +

research and development costs + financing.

a. Administrative costs:(2-6% of total product cost)

Consider the Administrative costs = 5% of total product cost

i.e.,Administrative costs = 0.05 * 589.82*107

= Rs. 29.491*107

b. Distribution and Selling costs: (2-20% of total product cost): includes

costs forsales offices, salesmen, shipping, and advertising.

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Consider the Distribution and selling costs = 15% of total product cost

i.e.,Distribution and selling costs = 15% of 589.82*107

= 0.15 *589.82*107

= Rs. 88.473*107

c. Research and Development costs: (about 5% of total product cost)

Consider the Research and development costs = 5% of total product cost

i.e., Research and Development costs = 5% of 589.82*107

= 0.05 *589.82*107

= Rs. 29.491*107

d. Financing (interest):(0-10% of total capital investment)

Consider interest = 5% of total capital investment

i.e., interest = 5% of 620.908*107

= 0.05*620.908*107

Interest = Rs. 31.0454*107

Thus, General Expenses = Rs. 178.5004*107

III. Total product cost= Manufacture cost + General Expenses

= (549.395*107) + (178.5004*107)

Total product cost = Rs. 727.8954*107

IV. Gross Earnings/Income:Wholesale Selling Price of Polystyrene per ton = $ 2000 (USD)

Let 1 USD = Rs. 50.00

Hence Wholesale Selling Price of Polystyrene per tonne = 2000 *50 = Rs. 100000

Total Income = Selling price * Quantity of product manufactured

= 100000 * (250 T/day) * (325days/year)

Total Income = Rs.8.125x109

Gross income = Total Income – Total Product Cost

= (8.125*109) – (727.8954*107)

Gross Income = Rs. 846.046*106

Let the Tax rate be 45% (common)

Taxes = 40% of Gross income

= 40% of 846.046*106

= 0.40*937.84*106

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Taxes = Rs. 338.4184 *106

Net Profit = Gross income - Taxes

Net profit = (846.046*106) – (338.4184 *106)

= Rs. 507.6276*106

Rate of Return:Rate of return = Net profit*100/Total Capital Investment

= 507.6276*106*100/ (620.908*107)

Rate of Return = 8.1755%

Break-even Analysis:Data available:

Annual Direct Production Cost = Rs.385.272*107

Annual Fixed charges, overhead and general expenses = Rs. 3.85272*109

Total Annual sales = Rs. 8.125* 109

Wholesale Selling Price of polystyrene per tonne = Rs. 100000

Direct production cost per ton of polystyrene = (385.272*107)/ (8.125 x 109/100000)

= Rs. 47418.09 per ton

Let ‘n’ TPA be the break even production rate.

Number of tons needed for a break-even point is given by

(3.85272*109) + (47418.09 *n) = (100000*n)

i.e., n = 73270.83 tons/year

n = 225.45 tons/day = 225.45 TPD

Hence, the break-even production rate is 225.45TPD or 48.20% of the considered plant

capacity.

12. BIBLIOGRAPHY

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1. ID Mall, Petrochemical Process Technology, Macmillan India Ltd., New Delhi,

2007.

2. E.E Ludwig, Applied Process Design For Chemical & Petro Chemical Plants,

Vol-1,2&3, Gulf Professional Publishing, 3rdEdition, Elsevier,2001.

3. Max Peters, Klaus D. Timmerhaus, Ronald West, Plant Design & Economics For

Chemical Engineers, 5th Edition, Tata McGraw-Hill, 2011.

4. Gael D.Ulrich, A Guide to Chemical Engineering Process Design & Economics,

Process Publishing, 1984.

5. P. Trambouze, Petroleum Refining: Materials and Equipment, Editions Technip,

2000.

6. Daniel A. Crowl, Joseph F. Louvar, Chemical Process Safety: Fundamentals with

Applications, 3rd Edition, Prentice Hall, 2011.

7. E.BruceNauman, Chemical Reactor Design, Optimization and Scale Up, McGraw-

Hill Publications.

8. James B. Rawlings, Job 6. Ekerdt, Chemical Reactor Analysis And Design

Fundamentals, Nob Hill Publishing, Madison, Wisconsin.

9. Nicholas P Chopey, Hand Book of Chemical Engineering Calculations, 3rd

Edition.10. Perry’s,Chemical Engineers Hand Book.

11. M.V.Joshi,Production of Polystyrene.

12. McCabe, Smith, Peter Harriot, Unit Operations of chemical engineering, 5th

edition, McGraw-Hill Publications.

13. Donald Q. Kern, Process Heat Transfer, International edition, 1965.

14. International Critical Tables, Vol.3.

Web Links:

1. www.freepatentsonline.com

2. www.indianprocessgeneral.com

3. www.docstoc.com

4. www.springerlink.com

5. www.sciencedirect.com

6. http://en.wikipedia.org

7. http://www.chemicalbook.com

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