1. INTRODUCTION

Phthalic anhydride was first reported by Lauret in 1836. In 1872, BASF developed

naphthalene oxidation process. Since then phthalic anhydride has been continuously

commercially produced. It was the first anhydride of a dicarboxylic acid to be

used commercially and its importance is comparable to acetic acid . The

most important derivatives of phthalic anhydride are polyesters, alkyl resins,

phthalocyanines and plasticizers like PVC . Till 1960, phthalic anhydride was

manufactured almost exclusively from naphthalene. The growing demand for

phthalic anhydride led to the search for alternative raw materials, such as o-

xylene, which is nowadays available in adequate quantities from cracking

plants and refineries.

Modern commercial processes for phthalic anhydride production are

based on the selective gas phase oxidation of o-xylene over V2O5/TiO2

catalysts, either in fixed or in fluidized bed reactors. The reaction proceeds at nearly

atmospheric pressure and in the temperature range of 360-400°C to give almost complete

conversion of o-xylene and selectivities for phthalic anhydride of 70-75%. This process is

complex, and involves different by-products resulting from the oxidation of

phthalic anhydride, such as o-tolualdehyde, phthalide and carbon oxides

(CO2 and CO). Due to the large exothermicity of the main reaction

(ΔH=−6800 kJ/mol), heat generation can produce hot spots, increasing the

risk of runaway reactions. Fluidized bed processes permit more efficient heat

removal and a better temperature control, avoiding yield losses and catalyst

degradation related with hot spots.

Phthalic anhydride is an important chemical intermediate. Its major outlets are phthalate

plasticizers, unsaturated polyesters and alkyd resins for surface coatings while its smaller volume

applications include polyester polyols, pigments, dyes, sweeteners and flame retardants.

It is traded in either molten form (requiring heated tankers) or as a white powder ('flake'). The

manufacture of phthalic anhydríde consumes almost all o-xylene produced so that sourcing a

suitable supply of high purity o-xylene is a critical consideration in the early stages of the

feasibility study.

1

Care must be taken in the process handling stages as explosive mixtures form easily

between phthalic anhydride dust and air, and spontaneous reaction occurs with many organic

compounds including skin tissue.

The first indigenous phthalic anhydride unit in India was put on stream by Herdillia

Chemicals Ltd. in a plant on the Thane-Belapur Road near Bombay in early 1968. The plant has

a capacity of 6000 tons/year.

1.1 Applications

Fig No. 1 Applications of Phthalic Anhydride-2009

There are various applications of phthalic anhydride-

1.1.1 Preparation of phthalate esters

Phthalate esters are widely used as plasticizers. In the 1980s, approximately 6.5×109 kg of these

esters were produced annually, and the scale of production was increasing each year, all from

phthalic anhydride. The process begins with the reaction of phthalic anhydride with alcohols,

giving the mixed esters:

C6H4(CO)2O + ROH → C6H4(CO2H)CO2R

The second esterification is more difficult and requires removal of water:

C6H4(CO2H)CO2R + ROH C6H4(CO2R)2 + H2O

2

The most important diester is bis(2-ethylhexyl) phthalate ("DEHP"), used in the manufacture of polyvinyl chloride.

1.1.2 Organic Synthesis

Phthalic anhydride is a precursor to a variety of reagents useful in organic synthesis. Important

derivatives include phthalimide and its many derivatives. Chiral alcohols form half-esters , and

these derivatives are often resolvable because they form diastereomeric salts with chiral amines

such as brucine. A related ring-opening reaction involves peroxides to give the useful peroxy

acid.

C6H4(CO)2O + H2O2 → C6H4(CO3H)CO2H

1.1.3 Precursor to dyestuffs

Phthalic anhydride is widely used in industry for the production of certain dyes. A well-known

application of this reactivity is the preparation of the anthroquinone dye quinizarin by reaction

with para-chlorophenol followed by hydrolysis of the chloride.

1.2 List of companies producing Phthalic Anhydride in India

IG Petrochemicals

Thirumalai Chemicals Ltd

Reshlon Cosmetics Pvt Ltd

Asian Paints Ltd

Durgapur Chemicals

Herdillia Chemicals Ltd

Indian Dyestuff Industries Ltd

Mysore Petrochemicals Ltd

Shri Ambuja Petrochemicals Ltd

1.3 Evaluation of Alternative Processing Routes

Phthalic anhydride can be produced using-

3

a) naphthalene

b) o-xylene

c) n-pentane

The first patent (BASF in 1896) used concentrated sulphuric acid in the presence of mercury

salts to perform the oxidation. The first vapour-phase process was patented in 1917. Since then,

there have been great improvements in the catalysts used, both in terms of increased yield and

reduced catalyst aging. Potassium-modified vanadium pentoxides (with promoters such as

molybdenum and manganese oxides) are now the most common catalysts used in PAN

production. The n-pentane process is the most recent development but requires a cheap supply of

raw material in order to be a viable option .

The main factors affecting the choice of feed stock are –

a] Yield (o-xylene gives more yield)

b] Availability ( naphthalene sources are becoming rarer)

c] Costs

d] Catalyst aging

e] Utility costs

f] Product quality

If o-xylene is preferred, a suitable source must also be determined. As nearly all the o-

xylene produced is used for phthalic anhydride manufacture there is unlikely to be an adequate

supply in the general market for a new plant. Therefore, a xylene separation plant, using a mixed

xylene feed, is often constructed on the same site as a PAN plant.

Apart from raw material selection, the main desígn consideration is the type of reactor.

Both fixed-bed and fluidized-bed processes are viable for the gas phase -process. The oxidation

reaction can be conducted at both high and low air ratios, which has significant implications for

the design of the reactor and downstream equipment. Plants throughout the world utilise a range

of technologies, including the liquid phase process which appears to be less viable.

The product typically needs to be purified to around 99.7%. The major contaminants are usually

maleic anhydride and single-ring aromatics. Both the raw materials and the product are skin, eye

and lung irritants. Appropriate safety equipment (overalls, face shield, long gloves) should be

worn by plant operators whenever they are likely to be in contact with any of the process hazard.

4

2. PHYSICO-CHEMICAL PROPERTIES

Phthalic

Anhydride

Maleic

Anhydride O-Xylene Oxygen

Molecular Formula C8H4O3 C4H2O3 C8H10 O2

Molar Mass (g/mol) 1.48 98.06 106.16 32

Appearance White Flakes White Crystals Colourless Liquid

Melting Point

(°C) 131 52.8 -24 -218.79

Boiling Point

(°C) 284.5 202 144 -182.95

Solubility in Water .62g/100g Reacts Insoluble

Flash Point

(°C) 152 102

Density

(gm/cc) 1.53 1.48 1.141

Viscosity

(cP) 0.55-1.2

1.61

at 60°C

8.102

at 20°C -

Heat of Fusion

(kJ/mol)

23.09

at 403.3K

12.26

at 325.7K

13.6

at 247.8K 0.444

Heat of Vaporization

(kJ/mol) - 54.8 36.24 at 417.6K 6.82

Specific Heat Capacity

(J/mole.K) 160

solid- 67.4, gas-

90.04

132.5(g)

,187(l) 29.378

Heat of Formation

(kJ/mole) -460.37 -470

19(g)

, -24.4(l) 0

Heat of Combustion

(kJ/mole) -3259.4 -1390.3 -4552.9 0

Entropy 180 353.6(g) 205.15

5

(J/mole.K) ,247(l)

Table No.1 Physico-chemical properties

3. MARKET ASSESSMENT

3.1 World Consumption

Plasticizers account for the majority of world phthalic anhydride consumption, followed by

alkyd resins and unsaturated polyester resins (UPR). Other smaller-volume applications

include polyester polyols, saccharin, pigments, dyes and flame retardants. Demand for most

downstream markets for phthalic anhydride is greatly influenced by general economic

conditions. As a result, demand for phthalic anhydride largely follows the patterns of the

leading world economies. Consumption of phthalic anhydride depends heavily on

construction/remodeling activity (residential and nonresidential), automotive production and

original equipment manufacture (OEM).

The following pie chart shows world consumption of phthalic anhydride:

Fig No. 2 World Consumption of Phthalic Anhydride-2009

6

Growth in world consumption of phthalic anhydride during 2009–2014 is expected to

vary greatly by application and region. For plasticizers, Western Europe and Asia will be the

leaders in volume growth; a robust economy in Asia for domestic and export markets and the

expected commissioning of large esterification units for the production of diphthalate (2-

propylheptyl) during 2009–2014 are the main factors for increased demand for phthalic

anhydride in these two regions. North American consumption of phthalic anhydride for

plasticizers is forecast to grow at an average annual rate of 1.0% during 2009–2014,

continued weak demand during 2010 in construction and automotive markets, especially in

the United States, will drag overall demand growth. Demand for phthalic anhydride in alkyd

resins is expected to decline in North America and Western Europe; most other regions are

forecast to experience moderate growth. Growth in phthalic anhydride demand for UPR is

also expected to vary by region; most Asian markets are forecast to see moderate-to-

significant growth in demand while moderate growth is forecast in North America and

Western Europe. World demand for phthalic anhydride is expected to start recovering in

2010–2012, largely as a result of improved construction/remodeling activity and stronger

OEM and automotive production. As a result, world consumption of phthalic anhydride is

forecast to grow at an average annual rate of 2.8% during 2009–2014.

Future concerns for the phthalic anhydride market include stricter environmental

regulations affecting and/or limiting the use of phthalates. Consumption of several phthalates

is forecast to diminish due to limits on use, they will be replaced largely by other phthalates,

benzoates, citrates and specialty plasticizers.

3.2 Phthalic anhydride prices and pricing information

3.2.1 Asian Market:

In the key China market, phthalic anhydride (PAN) spot market for imports were largely

subdued from early-September, falling from $990-1,030/tonne cost and freight (CFR), China

Main Port (CMP) in mid-August to $960-980/tonne, down $30-50/tonne. Buying appetite for

7

imports was thin as buyers continued to bypass such material for competitively-priced

domestic material. However, tighter-than-expected supply in the region due to maintenance

coupled with spiralling feedstock orthoxylene (OX) values led prices to reach a high of

$1,150-1,170/tonne CFR CMP in mid-November.

Market in the Asian region was weighed by poor conditions in the key China market.

After briefly exceeding the $1,000/tonne CFR mark in mid-August, prices fell by 3-5% to

$970-980/tonne for the week ended 3rd September. Spot prices rebounded in mid-September

in tandem with spiralling feedstock orthoxylene and limited availability to close at $1,220-

1,250/tonne CFR Southeast Asia for the week ended 12th November 2010.

3.2.2 European Market:

European Phthalic Anhydride contract prices were stable at €1,070-1,085/tonne free

delivered (FD) northwest Europe (NWE) for liquid and €1,005-1,060/tonne FD NWE for

flake, during the period mid-August to mid-November, tracking feedstock OX prices.

There were signs of a seasonal slowdown in demand towards the end of the period and

producers bemoaned low margins between orthoxylene and Phthalic Anhydride. Spot prices

were stable throughout the period at €1,050-1,100/tonne FD NWE for liquid and €1,100-

1,200/tonne FD NWE for flake, in line with orthoxylene.

3.2.3 US Market:

US Phthalic Anhydride prices were at 64.50-73.00 cents/lb free on board (FOB) Molten

for November, and 65.50-73.00 cents/lb delivered (DEL) Flake, both up 3.50 cents/lb from

the previous month. Prices will move up another 2 cents in December. Phthalic Anhydride

contracts have moved higher since Q3, following feedstock ortho-xylene values upward.

The uptrend in ortho-xylene contract was also prompted by rising mixed xylene (MX)

prices, and other higher feedstock prices, as well as energy heading into Q4. Despite the

increase, Phthalic Anhydride market participants expect a quiet market in November and 8

December, due to weaker demand, and weaker downstream demand from unsaturated

polyester resins (UPS).

3.3 Demand

The major outlet for phthalic anhydride (PA), accounting for just over half of

production, is in the manufacture of phthalate plasticisers, the main product being dioctyl

phthalate (DOP) which is used as a plasticiser in polyvinyl chloride (PVC). Hence, the

consumption of PA is mainly dependent on the growth of PVC, which is sensitive to general

economic conditions as it is consumed mainly in the construction and automobile industries.

The second largest use of PA, at around 18% of output, is in unsaturated polyester resins

(UPRs) which are used to produce fibreglass-reinforced resins. Their principal markets -

construction, marine and transportation are in the recreational area and so are also sensitive

to changes in economic conditions. In addition, UPR growth is tempered by the major

application areas having become saturated.

The third largest outlet is PA-based alkyd resins, which are used in solvent-based

coatings for architectural, machinery, furniture and fixture applications. They are in slow

decline due to limits in the level of volatile organic compounds in surface coatings. As a

result, there has been a switch to water-based and power coating technologies. In addition,

there is a trend towards decorative paints being based on vinyl acetate and acrylics. Small

volume uses for PA include the manufacture of dyes and pigments, detergents, herbicides

and insecticides, fire retardants, saccharin and polyester resin cross-linking agents.

World demand for PA is expected to start recovering in 2010-2012, largely as a result of

improved activity in the construction, automotive and original equipment manufacture

(OEM) sectors. US-based consultant SRI Consulting forecasts world consumption to grow at

an average rate of 2.8%/year during the 2009-2014 period. However, this growth is expected

to vary greatly by application and region.

9

3.4 India’s Industry Scenario

IG Petrochemicals is the world’s third largest manufacturer of Phthalic Anhydride with a

capacity of 1.1 lakh MT per annum. Phthalic Anhydride is used in the manufacture of resins,

paints and plasticizers. The other major Indian manufacturers of this product are Thirumalai

Chemicals, Asian Paints and Mysore Petrochemicals, a group company. The company is an

export-oriented unit (EOU) and exports 70% of its production. The Indian market for

Phthalic Anhydride is estimated at 1.25 lakh tonnes and growing at 5-6 % annually.

The current price of the main raw material Orthoxylene is at US$1300/MT and the price

of Phthalic Anhydride is US$1500/MT. Variable operating costs are US$60/MT resulting in

a net margin of US$140/MT, which is substantially higher than the margin of US$50/MT

during the downturn.

There is a strong growth volume of Phthalic Anhydride in the Indian market as a result

of the demand and strong growth in its end user industries like paints and plasticizers.

3.5 Risks and Concern

The number of Ortho-xylene producers in the world is limited. In India, Reliance

industries are the sole producers of Ortho-xylene. Also due to rising crude prices the cost of

Ortho-xylene is increasing resulting in cut-down in profit margins. Any disruption in supply

will have a negative effect on the performance of Phthalic Anhydride manufacturing

companies.

The major outlet for phthalic anhydride (PA), accounting for just over half of production,

is in the manufacture of phthalate plasticizers, the main product being dioctyl phthalate

(DOP) which is used as a plasticizer in polyvinyl chloride (PVC). Hence, the consumption of 10

PA is mainly dependent on the growth of PVC, which is sensitive to general economic

conditions as it is consumed mainly in the construction and automobile industries. Health and

environmental issues that surround phthalates used in plasticizers for PVC could also hinder

future growth prospects.

Future concerns for the phthalic anhydride market include stricter environmental

regulations affecting and/or limiting the use of phthalates. Consumption of several phthalates

is forecast to diminish due to limits on use. They will be replaced largely by other phthalates,

benzoates, citrates and specialty plasticizers.

11

4. MANUFACTURING PROCESS

Phthalic anhydride can be produced from o-xylene by oxidation with air-

…1

Other oxidation products include maleic anhydride, benzoic acid, carbon dioxide, etc.

Carbon dioxide is formed when the organic feedstock is completely oxidized. Historically,

naphthalene had been the feedstock for production of phthalic anhydride(PAN).It remained so

until after world war 2 when Oronite (now Chevron Phillips Chemcals Co.) commercialized

production of PAN using ortho-xylene.

The use of o-xylene as a feedstock was confined to the United States, until naphthalene

shortages in Europe promoted utilization of o-xylene. The switch to o-xylene was due to

diminishing supplies of naphthalene as a result of lower coke consumption and the increasing

availability of o-xylene from refinery operations.

In the United States, o-xylene became a more prominent feedstock as a result of a major

steel strike in 1959 that severely curtailed coal-tar naphthalene supplies. Despite the initially low

yields obtained , o-xylene became a preferred raw material because of its increasing supply

reliability compared to that of naphthalene. This spurred Research and Development activities to

improve the catalysts available.

12

So, Ortho-xylene is the clearly preferred modem day feedstock for phthalic anhydride

manufacture. Few naphthalene-based plants remain operational, and no new naphthalene plants

have been built since 1971. Ortho-xylene produces higher yie1ds , it is cheaper than naphthalene

and provides a more efficient process . Converting an existing plant to o-xylene can reduce raw

material costs by 25% and utility costs by 30%.

4.1 Process Description

Phthalic anhydride processes can be classified according to the type of reactor used.

Three reactor configurations have been commercially developed: (a) fixed bed vapour-phase

reactor; (b) fluidised-bed vapour-phase reactor; and (c) liquid phase reactor.

In PAN production using o-xylene as the basic feedstock, filtered air is preheated,

compressed, and mixed with vaporized o-xylene and fed into the multiple reactors. The reactors

contain the catalyst, vanadium pentoxide, and are operated at 340°C to 385°C. Small amounts of

sulfur dioxide are added to the reactor feed to maintain catalyst activity.

C8H10+3O2→C8H4O3+3H2O ...2

C8H10+7.5O2→C4H2O3+ 4H2O+ 4CO2 ...3

C8H10+10.5O2→8CO2+5H2O ...4

C8H10+6.4O2→8CO+5H2O ...5

Reaction (2) is the main reaction and it is assumed a 70% selectivity. Reaction (3) refers

to the formation of the by-product MA and a 10% selectivity is considered. Reactions (4) and (5)

represent the complete and incomplete combustions of o-xylene with 15% and 5% selectivity,

respectively.

Exothermic heat is removed by a molten salt bath circulated around the reactor tubes and

transferred to a steam generation system. The reactor effluent containing crude PAN plus

products from side reactions and excess oxygen passes to a series of switch condensers where the

crude PAN cools and crystallizes. The condensers are alternately cooled and then heated,

allowing PAN crystals to form and then melt from the condenser tube fins. The crude liquid is 13

transferred to a pretreatment section in which phthalic acid is dehydrated to anhydride. Water,

maleic anhydride, and benzoic acid are partially evaporated. The liquid then goes to a vacuum

distillation section where pure PAN (99.8 wt. percent pure) is recovered. The product can be

stored and shipped either as a liquid or a solid (in which case it is dried, flaked, and packaged in

multi-wall paper bags). Tanks for holding liquid PAN are kept at 150°C and blanketed with dry

nitrogen to prevent the entry of oxygen (fire) or water vapor (hydrolysis to phthalic acid). Maleic

anhydride is currently the only byproduct being recovered.

Major developments in phthalic anhydride manufacture in recent years have been in the

area of catalyst activity. The above process uses a catalyst that requires an air: o –xylene ratio of

only 9.5: 1 (compared to around 20: 1 for other technologies). This increases the catalyst

productivity by 40% and dramatically reduces the reactor size, and lowers the cluty of other

critical equipment (including the switch condensers). Energy requirements for blowers and

pumps are reduced by about 60%. The reduced flow of inerts in the reactor allows more sensible

heat to be extracted via the cooling salts. The plant can become completely energy self-sufficient

and can export considerable quantities of steam to neighboring plants. An after-cooler can also

be added to remove about half of the product phthalic anhydride. This increases the product

quality by reducing the concentration of impurities entering the product stream in the condensers.

This process has a lower capital cost and a higher operating efficiency compared with other

processes. This is a direct result of the low air to o-xylene ratio in the reactor. No electricity or

fuel is required and a significant steam credit can be exported. The final selling price for

phthalic anhydride produced by this process is likely to be lower than by competitive processes.

14

15

5. THERMODYNAMIC FEASIBILTY

Chemical thermodynamics is the study of the interrelation of heat and work with

chemical reactions or with physical changes of state within the confines of the laws of

thermodynamics. Chemical thermodynamics involves not only laboratory measurements of

various thermodynamic properties, but also the application of mathematical methods to the study

of chemical questions and the spontaneity of processes. The structure of Chemical

Thermodynamics is based on the first two laws of thermodynamics.

The primary objective of chemical thermodynamics is the establishment of a criterion for

the determination of the feasibility or spontaneity of a given transformation. In this manner,

chemical thermodynamics is typically used to predict the energy exchanges that occur in the

following processes:

1. Chemical reactions

2. Phase changes

3. The formation of solutions

The following state functions are of primary concern in chemical thermodynamics:

Internal energy (U)

Enthalpy (H).

Entropy (S)

Gibbs free energy (G)

Most identities in chemical thermodynamics arise from application of the first and second laws

of thermodynamics, particularly the law of conservation of energy, to these state functions.

The main reaction involved in phthalic anhydride production is-

C8H10 +3O2 → C8H4O3 + 3H2O ...6

16

Components O-xylene Water

Phthalic

Anhydride

ΔHf (kJ/mole)

g=19

l=-24.4 l=-285.83 s=-460.37

S (J/mole.K)

g=353.6

l=247 l=69.95 s=180

Cp (J/mole.K)

g=132.5

l=187 s=160

Table No. 02 Thermodynamic Properties

As oxygen is in its pure form, its entropy and enthalpy will be zero.

Calculating enthalpy, entropy and Gibb’s free energy for the above reaction,i.e. checking its

thermodynamic feasibility at room temperature, i.e.25°C

ENTHALPY of reaction-

ΔH = (ΔH f )products – (ΔH f)reactants

= [([ΔHf)phthalic anhydride + (ΔHf)water] – [(ΔHf)o-xylene + (ΔHf)oxyen]

= [-460.37+(-285.83)]-[19+0]

ΔH = -765.2 kJ/mole

ENTROPY of reaction-

ΔS = (S)products – (S)reactants

= [(S)phthalic anhydride + (S)water] – [(S)o-xylene + (S)oxygen]

17

= [180+69.95] – [353.6+0]

ΔS = -103.65 J/(mole.K) = - 0.10365 kJ/(mole.K)

GIBB’S FREE ENERGY-

ΔG = ΔH - TΔS

= -765.2 - ( 298* (-0.10365))

ΔG = -734.31 kJ/mole

As ΔG is negative , the reaction is thermodynamically feasible at room

temperature(25°C).

It can be concluded that, if the reaction is thermodynamically feasible at room temperature,

then it has to be thermodynamically feasible at higher temperatures.

18

6. KINETICS

The vapour-phase oxidation of o-xylene over a vanadium pentoxide catalyst is

essentially first order with respect to the o-xylene concentration. However, above a maximum o-

xylene concentration (which depends only on the specific type of catalyst and is independent of

temperature while the catalyst remains activated) the catalyst deactivates irreversibly and the

reaction rate decreases rapidly. Deactivation occurs when the valence-state of vanadium changes.

New developments have focussed on finding additives to prevent this from happening. The low

air ratio (LAR) catalyst can sustain the reaction up to a concentration of 2.77 mole % o-xylene,

compared with only 1.0-1.4% in other catalysts.

There are at least three significant reaction mechanisms which occur at the temperatures

encountered within the reactor. Below 370°C, the reaction is first order with respect to the

oxygen concentration and the rate constant is low. The selectivity for phthalic anhydride is high

but conversion of the feed may not be complete and the product is likely to undergo further

combustion.

Between 370°C and 440°C, the reaction is first order with respect to the hydrocarbon.

The rate constant is significantly higher, the selectivity remains high and the o-xylene conversion

is essentially complete.

Above 440°C (and below 550°C), the reaction is also first order with respect to

hydrocarbon concentration but conforms to a third reaction mechanism. The activation energy is

substantially less, the rate constant is higher and, because the activation energy is low, the

reaction rate is almost independent of temperature. The selectivity for phthalic anhydride begins

to decrease at higher temperatures as side reactions and complete oxidation become more

likely. The catalyst is irreversibly deactivated if the surface temperature exceeds 500°C. There

will be a temperature drop from the gas to the catalyst surface of 10-50°C.

Thus, the maximum allowable gas temperature is 510-550°C. The gas temperature in the

reactor should, therefore, be controlled so that the bulk of the reaction occurs from

440-510°C.

19

7. MATERIAL SAFETY DATA SHEET(MSDS)

7.1 MSDS – Phthalic Anhydride

7.1.1 Chemical Product

MSDS Name – Phthalic Anhydride

Synonym- 1,3-Isobenzofurandione , 1,2-Benzene Carboxylic Acid Anhydride

7.1.2 Composition

CAS# Chemical Name % EINECS#

85-44-9 Phthalic Anhydride 99 201-607-5

Table No.5 CAS Details-PAN

Hazards Symbol-XN

7.1.3 Hazards Identification

Eye: Risk of serious damage to eyes.

Skin: Causes skin irritation. May cause sensitization by skin contact.

Ingestion: Harmful if swallowed. May cause irritation of the digestive tract.

Inhalation: Causes respiratory tract irritation. May cause respiratory sensitization.

Chronic: May cause liver and kidney damage. Repeated exposure may cause

sensitization dermatis.

Repeated exposure may cause allergic respiratory reaction (asthma).

7.1.4 First Aid Measures

Eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the

upper and lower eyelids. Get medical aid.

20

Skin: Get medical aid. Flush skin with plenty of water for at least 15 minutes while

removing contaminated clothing and shoes.

Ingestion: Get medical aid. Wash mouth out with water.

Inhalation: Get medical aid immediately. Remove from exposure and move to fresh air

immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen.

Get medical aid.

7.1.5 Fire Fighting Measures

General Information: As in any fire, wear a self-contained breathing apparatus in

pressure demand, MSHA/NIOSH (approved or equivalent), and full protective gear. This

material in sufficient quantity and reduced particle size is capable of creating a dust explosion.

Extinguishing Media: Use water spray, dry chemical, carbon dioxide, or chemical

foam.

7.1.6 Accidental Release Measures

General Information: Use proper personal protective equipment.

Spills/Leaks: Vacuum or sweep up material and place into a suitable disposal container. Do

not let the chemical enter the environment.

7.1.7 Handling and Storage

Handling: Avoid breathing dust, vapor, mist, or gas. Avoid contact with skin and eyes.

Avoid ingestion and inhalation.

Storage: Store in a cool, dry place. Store in a tightly closed container.

7.1.8 Exposure Controls, Personal Protection

Engineering Controls: Facilities storing or utilizing this material should be equipped with

an eyewash facility and a safety shower. Use adequate ventilation to keep airborne

concentrations low.

Exposure Limits CAS# 85449:

United Kingdom, WEL TWA: 4 mg/m3 TWA United Kingdom,

WEL STEL:12 mg/m3 STEL

21

United States OSHA: 2 ppm TWA; 12 mg/m3 TWA

Belgium TWA: 1 ppm VLE; 6.2 mg/m3 VLE

France VLE: 6 mg/m3 VLE

Germany: 1 mg/m3 TWA (inhalable fraction)

Japan: 0.33 ppm Ceiling; 0.2 mg/m3 Ceiling

Malaysia: 1 ppm TWA; 6.1 mg/m3 TWA

Netherlands: 2 mg/m3 STEL Netherlands: 1 mg/m3 MAC

Spain: 1 ppm VLAED; 6 mg/m3 VLAED

Personal Protective Equipment

Eyes: Wear chemical splash goggles.

Skin: Wear appropriate protective gloves to prevent skin exposure.

Clothing: Wear appropriate protective clothing to prevent skin exposure.

Respirators: Follow the OSHA respirator regulations found in 29 CFR 1910.134 or

European Standard EN149. Use a NIOSH/MSHA or European Standard EN 149 approved

respirator if exposure limits are exceeded or if irritation or other symptoms are experienced.

7.1.9 Stability and Reactivity

Chemical Stability: Stable under normal temperatures and pressures.

Conditions to Avoid: Incompatible materials, exposure to moist air or water.

Incompatibility with other materials: Strong oxidizing agents, strong reducing agents,

strong acids, strong bases, nitric acid, sodium nitrate.

Hazardous Decomposition Products: Carbon monoxide, carbon dioxide.

Hazardous Polymerization: Will not occur

7.1.10 Toxicological Information

RTECS#: CAS# 85449:TI3150000

LD50/LC50: RTECS:

CAS# 85449: Draize test, rabbit, eye: 50 mg/24H Moderate;

Draize test, rabbit, skin: 500 mg/24H Mild;

Inhalation, rat: LC50 = >210 mg/m3/1H;

Oral, mouse: LD50 = 1500 mg/kg;22

Oral, rat: LD50 = 1530 mg/kg;

Skin, rabbit: LD50 = >10 gm/kg;

.

Other:

Carcinogenicity: Phthalic anhydride Not listed as a carcinogen by ACGIH, IARC, NTP,

or CA Prop 65.

Other: See actual entry in RTECS for complete information. The toxicological properties

have not been fully investigated.

7.1.11 Ecological Information

H Ecotoxicity: Fish: Leuciscus idus: LC50 313mg/l; 48h; .

Other: Do not empty into drains.

Biodegradability: 99%/14d

7.1.12 Regulatory Information

European/International Regulations

European Labeling in Accordance with EC Directives

Hazard Symbols: XN

Risk Phrases:

R 22 Harmful if swallowed.

R 37/38 Irritating to respiratory system and skin.

R 41 Risk of serious damage to eyes.

R 42/43 May cause sensitization by inhalation and skin contact.

Safety Phrases:

S 22 Do not breathe dust.

S 24/25 Avoid contact with skin and eyes.

S 26 In case of contact with eyes, rinse immediately with plenty of water and seek medical

advice.

S 37/39 Wear suitable gloves and eye/face protection.

S 46 If swallowed, seek medical advice immediately and show this container or label.

WGK (Water Danger/Protection)

CAS# 85449: 023

Canada

CAS# 85449 is listed on Canada's DSL List

US Federal

TSCA

CAS# 85449 is listed on the TSCA Inventory.

7.2 MSDS- Maleic Anhydride

7.2.1 Chemical Product

MSDS Name-Maleic Anhydride

Synonym- Toxilic Anhydride, 2,5-Furadione

7.2.2 Composition

CAS# Chemical Name %

108-31-6 Maleic Anhydride 99.5 min

Table No.6 CAS Details-MAN

7.2.3 Hazards Identification

Corrosive- Causes eye and skin burns

Harmful or fatal if swallowed

Harmful if absorbed through skin

Grinding may produce flammable dust/air mixtures

Molten product can cause thermal burns

Causes respiratory tract irritation and can cause damage

May cause allergic skin and respiratory (asthma like) reaction

7.2.4 First Aid Measures

Ingestion: Do not induce vomiting. Have a conscious person drink several glasses of water

or milk. Seek immediate medical attention

Inhalation: Allow the victim to rest in a well ventilated area. Seek immediate medical

attention

24

Skin Contact: After contact with skin, wash immediately with plenty of water. If irritation

persists seek medical attention. Wash contaminated clothing before reusing

Eyes : Immediately flush with water for at least 15 minutes, keeping eyelids open. Seek

medical attention.

7.2.5 Fire Fighting Measures

Extinguishing Media: Small fire: Carbon dioxide, water, foam.

Large fire: Water spray, fog or foam, do not use water jet.

DO NOT USE DRY CHEMICAL: Large volumes of gases could

be produced by reaction with Maleic Anhydride.

Special Fire-Fighting Procedures: Wear self-contained breathing apparatus with full face

piece operated in the positive pressure demand mode and full body protection when fighting fires

Hazardous Combustion Products: Carbon Dioxide, Carbon Monoxide.

Unusual Fire and Explosion Hazards: Unstable, or air-reactive or water-reactive chemical

involved . Vapors from melted material can be ignited. Keep melted material away from ignition

sources. May form flammable dust-air mixtures when finely divided. Prevent dust buildup by

providing adequate ventilation during grinding or milling

7.2.6 Accidental Release Measures

Personal Precautions: Avoid breathing dust. Pressure demand air supplied respirators

should always be worn when the airborne concentration of the contaminant or oxygen is

unknown. Otherwise, wear respiratory protection and other personal protective equipment as

appropriate for the potential exposure hazard. Wear gloves, goggles, and protective clothing to

avoid contact with eyes, skin, or clothing. Recycle, if possible. Use appropriate tools to put the

spilled solid in a waste disposal container. If necessary, neutralize the residue with a dilute

solution of sodium hydroxide. Do not dry sweep or use methods that increase dusting. Prevent

entry into sewers and waterways.

25

7.2.7 Handling and Storage

Handling: Eye wash and safety shower should be available nearby when this product is

handled or used. Minimum feasible handling temperatures should be maintained. Avoid

generating mist or dust. Exercise care when opening bleeders and sampling ports. Do not breathe

gas, fumes, vapor or spray. Do not ingest. Avoid contact with skin and eyes. After handling,

always wash hands thoroughly with soap and water.

Storage: Store away from incompatible materials. Store at temperatures not exceeding

70°C (158°F). Contains moisture sensitive material -- store in a dry place.

7.2.8 Exposure Control

Eye/Face: Avoid eye contact. Chemical type goggles with face shield must be worn. Do not

wear contact lenses.

Skin : Protective clothing such as coveralls or lab coats must be worn. Gloves resistant

to chemicals and petroleum distillates required. When handling large quantities, impervious

suits, gloves, and rubber boots must be worn. Remove and dry-clean or launder clothing soaked

or spoiled with this material before reuse. Dry cleaning of contaminated clothing may be more

effective than normal laundering. Inform individuals responsible for cleaning of potential

hazards associated with handling contaminated clothing.

Respiratory : Airborne concentrations should be kept to the lowest levels possible. If vapor,

mist or dust is generated and the occupational exposure limit of the product is exceeded, use

appropriate NIOSH or MSHA approved air purifying or air supplied respirator after determining

the airborne concentration of the contaminant. Air supplied respirators should always be worn

when airborne concentration of the contaminant or oxygen content is unknown.

Exposure Limits : TLV-TWA: 0.1 ppm 8 hours (ACGIH TLV, United States, 2002)

TWA: 0.25 ppm 8 hours (OSHA PEL, United States, 1971)

TWA: 1 mg/m3 8 hours (OSHA PEL, United States, 1971)

7.2.9 Stability and Reactivity

Chemical Stability: The product is stable except when in contact with water

Conditions to Avoid : Incompatible materials, moisture

Incompatible materials : May react violently with amines, alkali metal ions such as

Sodium or Potassium, and bases. At temperatures above 150°C, these materials, at 26

concentrations as low as 200 ppm., can trigger a rapid decomposition and polymerization

reaction that would produce heat and gas and cause equipment to rupture.

Hazardous Decomposition Products : Toxic levels of Carbon monoxide, carbon dioxide,

irritating aldehydes and ketones may be formed on burning. Heating in air may produce irritating

aldehydes, acids, and ketones.

Hazardous Polymerization : Will not self-polymerize but can undergo uncontrolled co-

polymerization in the presence of other monomers and catalysts.

7.2.10 Toxicological Information

Oral LD-50 (rat):1030 mg/kg Dermal LD-50 (rabbit): 2620 mg/kg

Skin irritation (rabbit): corrosive Eye irritation (rabbit): extremely irritating

Sensitization:The limited number of animal studies investigating the dermal or

respiratory sensitization potential of maleic anhydride have not shown conclusive evidence of

sensitization potential. Although there have been reports of human dermal or respiratory

sensitization from maleic anhydride exposures, the number of reports has been low when

compared to the number of potentially exposed individuals. Maleic anhydride has a low potential

for human dermal or respiratory sensitization.

Effects of Acute Exposure: Extremely dangerous in case of skin contact (corrosive,

irritant), of eye contact (irritant) and inhalation. Very dangerous in case of ingestion. Slightly

dangerous in case of skin contact (sensitizer). Eye contact can result in corneal damage or

blindness. Inhalation of dust will produce irritation to gastro-intestinal or respiratory tract,

characterized by burning, sneezing and coughing.

Effects of Chronic Exposure: Carcinogenic effects Not available.

Mutagenic effects: Not available. Teratogenic Effects: Not available. Toxicity of the product to

the Reproductive system: Not available. Repeated exposure of the eyes to low level dust can

produce irritation. Repeated skin exposure can cause local skin destruction or dermatitis.

Repeated inhalation can cause a varying degree of respiratory irritation or lung damage.

Repeated exposure to a highly toxic material may produce general deterioration of health by

accumulation in one or many human organs.

27

7.2.11 Ecological Information

Aquatic Toxicity LC50 - 96hr 230 mg/liter (mosquito fish) practically nontoxic LC50 -

24hr 150 mg/liter (blue gill sunfish) practically nontoxic

Mobility This product is not likely to volatilize rapidly into the air because of its low

vapor pressure.

Bio-accumulative potential This product is not expected to bio-accumulate through food

chains in the environment.

7.2.12 Disposal Considerations

Recycle if possible. Consult your local authorities. This product has the RCRA

characteristics of corrosivity, and is identified under RCRA as Maleic Anhydride. If discarded in

its present form, it would have the hazardous waste numbers D002 and U147. Under RCRA, it is

the responsibility of the user of the product to determine, at the time of disposal, whether the

product meets RCRA criteria for hazardous waste.

7.3 MSDS- O-xylene

7.3.1 Chemical product

MSDS Name- o-xylene

Synonym- 1,2 dimethylbenzol

7.3.2 Composition

CAS# Chemical Name % EINECS#

95-47-6 O-xylene 100 202-422-2

Table No.7 CAS Details-O-xylene

28

7.3.3 Hazards Identification

Skin: Irritant.Chronic exposure can cause dermatitis through defatting of tissue.rash or

blisters may occur.

Eyes: Irritant .Symptoms may include tearing, blurring, and sensitivity to light.

Inhalation: Can cause central nervous system depression. Irritation including naus,

headache, dizziness, drowsiness, loss of coordination, fatigue, lung congestion and lowered body

temperature.

Ingestion: Can cause digestive disorders, bloody vomit, intoxication, liver and kidney

damage.

7.3.4 First Aid Measures

Skin: Wash with soap and water and flush with water. Remove contaminated clothing

and wash before reuse. Get medical attention

Eyes: Immediately wash eyes with water for atleast 15 minutes

Inhalation: Move towards fresh air.

Ingestion: Do not induce vomiting.

7.3.5 Fire Fighting Measures

Fire and Explosion hazards: Severe fire hazard. Vapor/air mixtures are explosive. The

vapor is heavier than air. Vapors or gases may ignite at distant ignition sources and flash back.

Electrostatic discharges may be generated by flow or agitation resulting in ignition or explosion.

Extinguishing media: regular dry chemical, carbon dioxide, water, regular foam

Large fires: Use regular foam or flood with fine water spray.

Fire fighting: Move container from fire area if it can be done without risk. Cool containers

with water spray until well after the fire is out. Stay away from the ends of tanks. For fires in

29

cargo or storage area: Cool containers with water from unmanned hose holder or monitor nozzles

until well after fire is out. If this is impossible then take the following precautions: Keep

unnecessary people away, isolate hazard area and deny entry. Let the fire burn. Withdraw

immediately in case of rising sound from venting safety device or any discoloration of tanks due

to fire. For tank, rail car or tank truck: Evacuation radius: 800 meters (1/2 mile). Water may be

ineffective.

7.3.6 Accidental release Measures

Air Release: Reduce vapors with water spray. Stay upwind and keep out of low areas.

Soil Release: Trap spilled material at bottom in deep water pockets, excavated holding

areas or within sand bag barriers. Dike for later disposal. Absorb with sand or other non-

combustible material. Collect with absorbent into suitable container.

Water Release: Cover with absorbent sheets, spill-control pads or pillows. Neutralize.

Collect with absorbent into suitable container. Absorb with activated carbon. Remove trapped

material with suction hoses. Collect spilled material using mechanical equipment.

Occupational Release:

Avoid heat, flames, sparks and other sources of ignition. Stop leak if possible without personal

risk. Reduce vapors with water spray. Small spills: Absorb with sand or other non-combustible

material. Collect spilled material in appropriate container for disposal. Large spills: Dike for later

disposal. Remove sources of ignition. Keep unnecessary people away, isolate hazard area and

deny entry. Reportable Quantity (RQ): Notify Local Emergency Planning Committee and State

Emergency Response Commission for release greater than or equal to RQ (U.S. SARA Section

304). If release occurs in the U.S. and is reportable under CERCLA Section 103, notify the

National Response Center at (800)424-8802 (USA) or (202)426-2675 (USA).

7.3.7 Handling and Storage

Store and handle in accordance with all current regulations and standards. Store and handle

in accordance with all current regulations and standards. Grounding and bonding required.

Protect from physical damage. Store outside or in a detached building. Store with flammable

liquids. Keep separated from incompatible substances. Keep separated from incompatible

substances. Subject to storage regulations: U.S. OSHA 29 CFR 1910.106. Grounding and

bonding required.30

7.3.8 Exposure control

Ventilation: Provide local exhaust ventilation system. Ventilation equipment should be

explosion-resistant if explosive concentrations of material are present. Ensure compliance with

applicable exposure limits. Ventilation equipment should be explosion-resistant if explosive

concentrations of material are present. Provide local exhaust ventilation system.

Eye Protection: Wear splash resistant safety goggles. Provide an emergency eye wash

fountain and quick drench shower in the immediate work area. Wear splash resistant safety

goggles with a faceshield. Provide an emergency eye wash fountain and quick drench shower in

the immediate work area.

Clothing: Wear appropriate chemical resistant clothing.

Gloves: Wear appropriate chemical resistant gloves. Wear appropriate chemical resistant

gloves.

Respirator: The following respirators and maximum use concentrations are drawn from

NIOSH and/or OSHA. 900ppm Any chemical cartridge respirator with organic vapor

cartridge(s). Any powered, air-purifying respirator with organic vapor cartridge(s). Any

supplied-air respirator. Any self-contained breathing apparatus with a full facepiece.

Escape: Any air-purifying respirator with a full facepiece and an organic vapor canister.

Any appropriate escape-type, self-contained breathing apparatus.

7.3.9 Stability and reactivity

Reactivity: Stable at normal temperatures and pressure.

Conditions to avoid: Avoid heat, flames, sparks and other sources of ignition. Containers

may rupture or explode if exposed to heat. Keep out of water supplies and sewers.

Incompatibilities: oxidizing materials

Hazardous Decomposition: Thermal decomposition products: oxides of carbon

Polymerization: Will not polymerize

7.3.10 Toxicological Information

Toxicity data: 3617 mg/kg oral-rat LD50 (Phillips)

Local Effects: Irritant: inhalation, skin, eye31

Acute Toxicity Level: Moderately Toxic: ingestion

Target Organs: central nervous system

7.3.11 Ecological Information

Fish Toxicity: 16400 ug/L 96 hour(s) LC50 (Mortality) Fathead minnow (Pimephales

promelas)

Invertebrate Toxicity: 200 mg/L 24 hour(s) EC100 (Abundance) Water flea (Daphnia

magna)

Algal Toxicity: 4200 ug/L 8 hour(s) EC50 (Growth) Green algae (Selenastrum

capricornutum)

Other Toxicity: 73000 ug/L 48 hour(s) LC50 (Mortality) Clawed toad (Xenopus laevis)

32

8. MATERIAL BALANCE

Let us assume that 10 kmol of o-xylene is fed to a reactor.

Selectivity for PAN reaction= 0.7

C8H10 + 3O2 C8H4O3 + 3 H2O ...from equation (8)

O-xylene reacted = 7 kmol

Oxygen reacted = 21 kmol

PAN formed = 7 kmol

Water (g) formed = 21 kmol

Selectivity for complete combustion reaction=0.2

C8H10 + 10.5O2 5 H2O + 8CO2

O-xylene reacted = 2 kmol

Oxygen reacted = 21 kmol

Carbon dioxide formed = 16 kmol

Water (g) formed = 10 kmol

Selectivity for MAN reaction=0.1

C8H10 + 7.5 O2 C4H2O3 + 4 H2O + 4CO2

O-xylene reacted= 1 kmol

Oxygen reacted =7.5 kmol

Carbon dioxide formed = 4 kmol

Water(g) formed= 4 kmol

Maleic anhydride = 1 kmol

Molecular weight of o-xylene =106

Therefore 10 kmol of o-xylene = 1060 kg

On weight basis, Air : o-xylene = 10:1

Air fed =10,600 kg = 367.55 kmol

Oxygen, Nitrogen in air are 77.18 kmol, 290.37 kmol.

33

Excess Oxygen = 77.18 – 49.5 = 27.68 kmol

Nitrogen fed = 290.37 kmol

Material Balance around the reactor :

Reactants entering:

O-xylene = 10 kmol = 10*106 = 1060 kg

Oxygen fed = 77.18 kmol = 77.18*32 = 2469.76 kg

Nitrogen fed = 290.37 kmol = 290.37*28 = 8130.36 kg

Total weight = 1060+10600=11660 kg

Products leaving:

PAN = 7 kmol = 7*148 = 1036 kg

H2O(g) = 35 kmol=35*18 = 630 kg

CO2 = 20 kmol =20*44 = 880 kg

MAN = 1 kmol = 1*98 = 98 kg

O2 = 27.68 kmol = 27.68*32 = 885.76 kg

N2 = 290.37 kmol = 290.37 *28 = 8130.36 kg

Total weight = 11660.12 kg

Law of Conservation of mass is satisfied.

O-xylene

Air

Fig No. Reactants and Products entering and leaving Reactor34

PAN

H2O

CO2

MAN

O2

N2

REACTOR

Material Balance around the Switch Condenser:

Feed to switch condenser:

PAN = 7 kmol

H2O (g) = 35 kmol

CO2 = 20 kmol

MAN = 1 kmol

O2 = 27.68 kmol

N2 = 290.37 kmol

Assume that 2 mol% and 0.2 mol% of MAN and PAN present in the feed leave in the top stream.

Top Stream Leaving the Condenser:

PAN = (0.2/100)*7 = 0.014 kmol

H2O (g) = 35 kmol

CO2 = 20 kmol

MAN = (2/100)*1= 0.02 kmol

O2 = 27.68 kmol

N2 = 290.37 kmol

Bottom stream Leaving the Condenser:

MAN = 0.98 kmol = 0.98*98 = 96kg

PA N = 6.986 kmol = 6.986*148 = 1034 kg

35

MAN

MAN

CO2

CO2

PAN

PAN

MAN

O2

O2

H2O

H2O

N2

N2

SWITCHCONDENSOR

Fig No. Reactants and Products entering and leaving the Switch Condensor

Material Balance around the Distillation Column:

Feed to Distillation Column:

MAN = 96 kg

PA N = 1034 kg

Total (F) = 1130 kg

PAN composition (weight basis) in Distillate (D) and Residue (W) are 2% and 98% respectively

Overall Material Balance: F = D + W where F= 1130 kg (wt. basis)

PAN balance (wt. Basis) : xF*F = xD*D + x W* W

Where xF*F = 1034 kg

xD = 0.002

xW = 0.998

Solving above two equations, we get

D = 94.116 kg; W = 1035.88 kg

Fig No. Reactants and Products entering and leaving the Distillation Column36

PAN

MAN

PAN

DISTILLATE

BOTTOMS

DISTILLATION COLUMN

Aim: To produce PAN product, 60000 metric tons/year, 99.8 wt% purity.

Here 1 year = 300 days

60,000 tons/yr = 200 tons/day=25/3 tons/hr=25000/3 kg/hr;

Therefore, o-xylene to be charged to reactor = ((25000/3)*10)/1035.88 = 80.45 kmol/hr

Start: o-xylene fed = 80 kmol/hr

A] Material Balance around the reactor :

Reactants entering:

o-xylene = 80 kmol/hr = 80*106 =8480 kg/hr

On weight basis,Air: o-xylene = 10:1

Air fed = 84,800 kg/hr = 2940.4 kmol/hr

Oxygen fed = 617.5 kmol/hr = 617.5*32 = 19760 kg/hr

Nitrogen fed = 2322.9 kmol/hr = 22322.9*28 = 65040 kg/hr

Reactants Kmol/hr Molecular Weight Kg/hr

O-xylene 80 106 8480

O2 617.5 32 19760

N2 2322.9 28 65041.2

Total=3020.4kmol/hr Total=93281.2kg/hr

Table No.8 Reactants entering the Reactor

Selectivity for PAN reaction= 0.7

C8H10 + 3O2 C8H4O3 + 3 H2O

37

o-xylene reacted = 80*0.7 = 56 kmol/hr

Oxygen reacted = 56*3 = 168 kmol/hr

PAN formed = 56*1 = 56 kmol/hr

Water(g) formed = 56*3 =168 kmol /hr

Selectivity for complete combustion reaction=0.2

C8H10 + 10.5º2 5 H2O + 8CO2

o-xylene reacted = 80*0.2 =16 kmol/hr

Oxygen reacted =10.5*16 = 168 kmol/hr

Carbon dioxide formed = 8*16 = 128 kmol/hr

Water (g) formed = 5*16 = 80 kmol/hr

Selectivity for MAN reaction=0.1

C8H10 + 7.5 O2 C4H2O3 + 4 H2O + 4CO2

o-xylene reacted = 80*0.1 = 8 kmol/hr

Oxygen reacted = 7.5 *8 = 60 kmol/hr

Carbon dioxide formed = 4*8 = 32 kmol/hr

Water (g) formed = 4*8 = 32 kmol/hr

Maleic anhydride = 8*1 = 8 kmol/hr

Excess oxygen = 617.5-(168+168+60) = 221.5 kmol/hr

Products Kmol/hr Molecular Weight Kg/hr

PAN 56 148 8288

H2O(g) 280 18 5040

CO2 160 44 7040

MAN 8 98 784

O-xylene 0 106 0

O2 221.5 32 7088

N2 2322.9 28 65041.2

Total=3048.4Kmol/hr Total=93281.2kg/hr

38

Table No.9 Products leaving the Reactor

Law of Conservation of mass is satisfied.

O-xylene =8480kg/hr

Air= 84801.2 kg/hr

Fig No. Reactants & Products in a Reactor along with Massflow Rates

B] Material Balance around the Switch Condenser:

Feed to switch condenser:

PAN = 56 kmo/hr

H2O = 280 kmol/hr

CO2 = 160 kmol/hr

MAN = 8 kmol/hr

O2 = 221.5 kmol /hr

N2 = 2322.9 kmol/hr

Assume that 2 mol% and 0.2 mol% of MAN and PAN are present in the feed leaving the top

stream.

Top Stream Leaving the Condenser:

PAN = (0.2/100)*56 = 0.112 kmol /hr

H2O(g) = 280 kmol/hr39

H2O=5040kg/hr

N2 =65041.2kg/hr

O2 = 7088kg/hr

MAN=784kg/hr

PAN=8288kg/hr

CO2 = 7040kg/hr

REACTOR

CO2 = 160 kmol/hr

MAN = (2/100)*8 = 0.16 kmol/hr

O2 = 221.5 kmol /hr

N2 = 2322.9 kmol/hr

Bottom stream Leaving the Condenser:

MAN = 7.84 kmol/hr = 7.84*98 = 768.3 kg/hr

PA N = 55.888 kmol/hr = 55.888*148 = 8271.4 kg/hr

Total = 9039.7 kg/hr

40

MAN=768.3kg/hr

PAN=8271.4kg/hr

O2=7088kg/hr

N2=65041.2kg/hr

MAN=15.68kg/hr

MAN=784kg/hr

PAN=8288kg/hr

PAN=16.576kg/hr

N2=65041.2kg/hr

O2=7088kg/hr

H20=5040kg/hr

H20=5040kg/hr

CO2=7040kg/hr

CO2=7040kg/hr

SWITCHCONDENSOR

Fig No. Massflow rates of Reactants & Products in Switch Condensor

C] Material Balance around the Distillation Column:

Feed to Distillation Column:

MAN = 768.3 kg/hr

PA N = 8271.4 kg/hr

-----------------------------------

Total (F) = 9039.7 kg/hr

------------------------------------

PAN composition (weight basis) in Distillate(D) and Residue(W) are 0.2% and 99.8%

respectively.

Overall Material Balance: F = D + W , where F= 9039.7 kg/hr

(wt basis)

PAN balance (wt basis) : xF*F = xD*D + x W* W

Where xF*F=8271.44 kg

xD= 0.002

xW= 0.998

Solving above two equations, we get

D= 753.19 kg/hr; W= 8286.50 kg/hr

Rounding Off:

Phthalic anhydride Product (W) = 8200 kg/hr

Distillate product (D) = 760 kg/hr

41

DISTILLATIONCOLUMN

MAN=768.3kg/hr

PAN=8271.4kg/hr

PAN=8286.5kg/hr

DISTILLATE=753.19kg/hr

Fig No. Massflow rates of reactants & products in Distillation Column

9. ENERGY BALANCE

DATA:Vapor Heat Capacities (range 150°C - 450°C) Cp (cal/moleK) a bT cT 2 dT3 , T in (K)

Liquid Heat Capacity (range 125°C - 200°C)for any organic: Cp (cal/moleC) 41.69 7.773 102 , T in (°C)Vapor Pressures (range 100°C - 300°C)form:

Normal heats of vaporization (cal/mole)

Since the gases are at high temperature and low pressure, the gases can be assumed to be ideal . Compound mole fractiono-xylene 0.0265air 0.9735

Specific heat of reacting mixture (air and o-xylene) (Cp[M1]) = 6.386 + 4.885 *10-3 *T -2.179 *10-6 *T2 + 4.765*10-9 *T3 -3093.39 T -2

∆Hnet=3020.4*1000∫(6.386+4.885*10-3*T–2.179*10-6*T2+4.765*10-9*T3–3093.39*T-2)dTwhere T is from 298 K to 593 K

= 3020.4*1000*2526.38 = 0.763*1010 Cal/hr = 31940.46 MJ/hr∆H1= o-xylene stream;

∆H2= air stream;

∆H1+∆H2 =∆H net

42

Now, ∆H1= 80*1000*∫(-3.786 + 0.1424*T – 8.224*10-5*T2 + 1.798*10-7*T3)dT where T is from 423 K to 610.5 K∆H2 = 27555.47 MJ/hr o-xylene stream:Assuming 1% losses,Heat transfer rate supplied by Natural gas to o-xylene stream=4385/0.99 = 4429.3 MJ/hrCalorific Value of Natural gas = 54 kJ/gAmount of Natural gas: m(54) = 4429.3 *1000 kJ/hr m=82 kg/hr

Air stream:Assuming 1% losses,Heat transfer rate supplied by steam to air stream = 27555.47/0.99 = 27833.81 MJ/hrEnergy Balance around the Reactor: Heat transfer rate required to raise the reacting mixture from 320 C to 360 C = 3020.4*1000* 386.08 = 0.1166 *1010 cal/hr = 4881.1 MJ/hrPAN reaction: C8H10 + 3O2 C8H4O3 + 3 H2O∆H 298 K = -371.79 + 3(-242) -19.01 = -1116.8 KJ/mol ∆H 633K = -1116.8 +11.814 = -1104.98 kJ/mol ∆H net(1)= n(∆H 633K ) = 56 *1000*(-1104.98)*1000=-61878.88MJ/hrMAN reaction:C8H10 + 7.5 O2 C4H2O3 + 4 H2O + 4CO2

∆H 298 K = -469.65 + 4(-242) + 4(-393.77) -19.01 = -3031.74 kJ/mol∆H 633K = -3031.74 -7.69 =-3039.43 kJ/mol ∆H net(2)= n(∆H 633K ) = 8*1000*-3039.43*1000 = -24315.44 MJ/hr

Complete Combustion:C8H10 + 10.5O2 5 H2O + 8CO2

∆H 298 K = 8(-393.77)+5(-242)-19.01 = -4379.17 kJ/mol∆H 633K = -4379.17 + 174.785= -4204.38kJ/mol

∆H net(3) = n(∆H 633K ) =16*1000*-4204.38*1000 = -67,270.16 MJ/hrOverall Heat transfer rate liberated = -61878.88 -24315.44-67270.16 = -153464.48 MJ/hrLet us allow the Products to leave the reactor at 400 C.∆HO2 = 288.68 MJ/hr

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∆HN2=(23 22.9*1000)(1218.53)=2830.51 MJ/hr ∆HMAN= (8000)*5392.32= 43.14 MJ/hr∆HCO2 = (160*1000)*1945.38 =(160*1000) * 1945.38 =311.26 MJ/hr∆HH2O = (280*1000)*1479.97=414.39MJ/hr∆HPAN= 600.41 MJ/hrOverall Heat utilized for raising products from 360 C to 400 C = 4488.4MJ/hr Net enthalpy heat rate change with in the reactor =4881.1-153464.5+4488.4 = -144095.01 MJ/hr144095.01 MJ/hr is to be utilized by molten salt.

Energy balance around the salt cooler: Q = m Cp ∆ T 144095.01 *106 = m *1560*(395-150) m= 377 tons/hr =104.72 kg/sEnergy balance around the heat exchanger – 2(HE-2):

Boiler feed water (bfw) available at 549 kPa,90 C

It is to be delivered at high pressure (4300 kPa)Saturated steam enthalpy (at 4300 kPa and 254 C)=2799.4 kJ/kgAt heat exchanger-2, 144095.01*106= m(2799.4*1000) m = 51473.5 kg/hr Flow rate of boiler feed water = 51473.5 kg/hr

Heat possessed by products leaving reactor at 400 C :∆HO2=221.5 *1000*11633.92 = 2576.9 MJ/hr∆HN2 = (2322.9*1000)*11120.96 = 25832.9 MJ/hr ∆HMAN = 8000*40662.54 = 325.3 MJ/hrBoiling point of water = 406.7 K at 3 atm∆HH2O = 16403.4 MJ/hr∆HPAN=56*1000*82634.21= 4627.52 MJ/hr∆HCO2 =160*1000*16441.09 =2630.58 MJ/hr

Overall Heat possessed by products leaving the reactor = 2576.9 + 25832.9 +325.3 +2630.58 +16403.4+4627.52 = 52396.6 MJ/hrEnergy balance around the heat exchanger – 3(HE-3): Energy possessed by stream after heat exchanger-3 :∆HO2 = 221.5 *1000* (3735.32)=827.37 MJ/hr∆HN2 =2322.9 *1000 *3651.46=8481.97 MJ/hr∆HMAN = 8*1000*8713.958=69711664 cal/hr=291.8 MJ/hr∆HH2O =13929.75 MJ/hr∆HPAN=56*1000*8713.958=487981648 cal/hr=2042.59 MJ/hr

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∆HCO2 = 794.86 MJ/hrTotal Heat = 26368.3 MJ/hr52397-26368=26029 MJ/hr is being utilized by heat exchanger – 3,Boiling Point of water = 427 K at 525 kPa Saturated steam enthalpy =2749.7 kJ/hrm (2749.7*1000) =26029 *106

m= 9466 kg/hrFlow rate of cool water = 9466 kg/hr

Energy balance around the Switch Condenser:Energy possessed by effluent stream:

Effluents leave the heat exchanger – 3 at 140 C∆HO2 = 221.5 *1000* (3431.55) = 760.09 MJ/hr∆HN2 =2322.9 *1000 *3358.4=7801.2 MJ/hr

∆HMAN= 160*9797==1.57 MJ/hr∆HH2O =13832.94 MJ/hr(since B.P of water = 393 K at 2 atm)∆HPAN= 112 * 20480 = 2.29 MJ/hr∆HCO2 =160*1000*4548.34= 727.73 MJ/hrTotal energy possessed by effluent stream =23125.76 MJ/hrSince Cp (MAN) =Cp (PAN) in liquid state, we have

Cp (MAN) =Cp (PAN) = Cp (Feed)Specific enthalpy = 7972.15 Cal/mol = 33369.8 kJ/kmolTotal enthalpy of feed = (55.888+7.84) (33,369.8) = 63.728 *33,369.8 = 2126.6 MJ/hr Energy remaining =26368.3 – (2126.64+23,125.8) = 1115.9 MJ/hrLet cool water be condensing medium and its temperature rise by 10Ci.e., from 30 C to 40C 1115.9 *1000 =m (4.18)(40-30) m=26696.2 kg/hr=26.7 T/hr26.7 T/hr of cooling water is being used.

Energy balance around the Distillation Column:

In W, 55.62 and 1.71 kmol/hr of PAN and MAN are present.In D, 0.01 and 7.67 kmol/hr of PAN and MAN are present.Solidification point of PAN = 130.8CBottom product is at 150CSpecific enthalpy of bottom product (hW ) =8713.96 cal /mol =36474.9 kJ/kmolTotal Enthalpy of bottom product = (55.62+1.71) (36474.9) = 57.33 * 36474.9 = 2091.1 MJ/hrTop Product is at 60C (333K)

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Specific enthalpy of top product (hD) = 2317.48 cal/mol =9700 .5 kJ/kmol Total enthalpy of Top product =(0.01+7.67) (9700.5) =7.68 *9700.5 =74.499 MJ/hr

Composition of MAN and PAN in D are 0.998,0.0013Assuming PAN and MAN obey’s Raoults law, y = ax/ (1+(a-1)x); where a= √( atop* a bottom)Here MAN is more volatile component.Using Antonie’s equation,Vapor pressure of MAN at 333 K, 423 K is 3.536 mm Hg, 186.2 mm Hg.

Vapor pressure of PAN at 333 K, 423 K is 0.153 mm Hg, 17.36 mm Hg.atop =3.536/0.153 =23.11; a bottom =186.2/17.36= 10.73

a=sqrt( atop* a bottom) =sqrt(23.11*10.73) = 15.75y = 15.75x/(1+14.75x) is equilibrium relation.Let us assume that boiling point of feed varies linearly with compositionBoiling point of PAN and MAN are 560 K and 473 KFor feed composition,Boiling point of feed =(55.888*560+7.84*473)/(55.888+7.84) = 549.3 KSpecific enthalpy of feed if feed is saturated liquid =18,752.08 cal/mol = 78492.5 kJ/kmolSpecific enthalpy of feed = 7972.15 cal/mol =33369.8 kJ/kmol Normal Heats of vaporization

PAN 11850 cal/mol = 49601.73 kJ/kmolMAN 5850 cal/mol = 24486.93 kJ/kmol Let us assume that latent heat of vaporization of feed varies linearly with compositionλ feed = (55.888*49601.73 +7.84 *24486.93)/(55.888+7.84) = 46511.66 kJ/kmol

Specific enthalpy of feed if feed is saturated vapor = Specific enthalpy of saturated liquid + Latent heat of vaporization of feed =78492.5 +46511.66 =125004.2 kJ/kmolq= (Hv - hF )/(Hv– hL ) = (125004.2-33369.8)/(125004.2- 78492.5) = 1.97Assume that constant Molar overflow rate is prevailing.Feed line is y = qx/(q-1) – xF /(q-1) = 2.03 x -0.127Point of intersection of feed line and equilibrium line is 2.03 x -0.127 = 15.75x / (1+14.75x) x = 0.53 => y = 0.95For minimum reflux (Rm) Top section operating line passes through pinch point (0.53,0.95) and (0.98,0.98)Slope = (0.98- 0.95)/(0.98- 0.53) = 1/15 = Rm / ( Rm + 1) Rm =1/14Ropt = 1.5 Rm =1.5/14 =0.107Mole fraction of MAN in top product =0.998

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Mole fraction of PAN in top product =0.0013Assuming boiling point varies linearly, Boiling point of Top product = 0.998 * 473 + 0.0013 *560 =472.78Kλ top product = 0.998*24486.93 +0.0013 *49601.73 = 24502.43 kJ/kmolSpecific enthalpy of top product if it is saturated vapor = 12628.32 +24.502.43 = 37130.75 kJ/kmol

Energy balance around Total Condenser:

V*HV = D*hD + Lo* hLo + Qc

Using V=(R+1)D, Lo=R*D, hLo= hD

Q c = (R+1) D [HV –hD] =(1+0.107)(0.01+7.67 )[37130.75-9700.5] = 233.20 MJ/hrCooling water is available at 30C and let its temperature rise by 10C mCp∆T = 199182.16 kJ/hr m (4.18)(40-30) = 199182.16 kJ/hr m= 4765.12 kg/hr = 4.765 T/hr

Flow rate of cooling water = 4765.12 kg/hr = 4.765 T/hr

Overall Energy balance around Distillation Column: F*hF + QB = Q c + D*hD + W* hW 2126.6 + QB =233.20 +62.92 +2091.1 QB = 260.62MJ/hrReboiler load :Electrical Power to be supplied to Reboiler at a rate of 260.62 MJ/hr

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10. ENVIRONMENTAL CONSIDERATIONS

The environmental impact due to day-to-day operation and the potential environmental

damage that results from a plant accident or spill have been considered. Potential emissions to

the environment from the proposed phthalic anhydride plant have been assessed in three

categories:

(a) Airborne emissions

(b) Waterborne emissions and

(c) Solid waste.

The main process hazard which may occur during normal operation of phthalic anhydride

plants is the risk of PAN dust clouds forming from minor process breaches. PAN dust clouds are

both toxic and explosive. Air quality monitoring will be utilized to identify process breaches

producing dust clouds before they become hazardous. Appropriate breathing equipment will

always be available.

Safety will be a priority and detailed policies will be developed to ensure safe working

practices are cultivated. Employees from all groups and levels will be involved in safety on a

day-to-day basis. The use of appropriate protective equipment will be mandatory for both

employees and visitors in all process areas. Noise will be controlled through good design and

appropriate insulation, and will not exceed recommended levels.

10.1 Airborne Emissions

The Low Air Ratio process is the cleanest of the processes for phthalic anhydride

production. Normal operating conditions will produce only two significant discharges to the

environment which are shown in Figure.

(a) Non-condensable reaction by-products that remain with the air as it is rejected from the

process to the environment.

(b) Heavy residue from the bottoms of the rectification column.

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The reaction by-products are mostly light organic vapours. A scrubbing unit will be

installed in order to reduce the concentrations of contaminants to less than 25 ppm PAN, 10 ppm

maleic anhydride and 3 ppm benzoic acid prior to discharge to the atmosphere. A 50 m stack

should disperse these concentrations to acceptable levels. The total amount of PAN vented to the

atmosphere will be less than 1 kg/hr. However approximately 15 T/hr of carbon dioxide will be

produced as a by-product of the main synthesis reaction and this gas will need to be vented to the

atmosphere. This is a negligible quantity when compared with the discharges from other local

industries.

10.2 Waterborne Emissions

Water is not part of the phthalic anhydride process and will not come into direct contact

with any process stream in the system. Air coolers will be used to satisfy most of the process

cooling requirements so that cooling water usage will be minimal. The cooling-water circuit is a

closed system and does not use either sea or river water, and it makes only small discharges of

pH-neutral water to the environment. Biological fouling is controlled with phosphate additives

rather than the more environmentally hazardous chromate additives. Steam requirements will be

essentially met by the process itself using the heat generated by the PAN reaction. An

interconnection with the adjoining utilities plant will be installed but will generally only be used

to export steam. Process contaminants that might enter the steam system through exchanger leaks

or other process disturbances will be scrubbed at the shared utilities plant, so that condensate can

be recycled to reduce energy consumption and chemical treatment costs.

10.3 Solid Waste

No solid residue is expected from the phthalic anhydride process. However,

bioremediated waste from the adjoining utilities plant which may be partially sourced from the

PAN plant wastewater can be cleanly incinerated in a combustion unit if the heating value is

sufficiently high. Heat released by this process will be used for boiler feed-water preheating to

minimize energy consumption in the utilities plant. The requirements for an incinerator in the

common utilities plant will have to be assessed. Other options such as extended bioremediation

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of heavy organic residues, may be more economical as the incinerator will require a complex

control system to monitor its performance, to regulate the fuel: air ratio, and to safeguard

operation against process disturbances that could potentially result in unburned product being

emitted directly to the environment.

10.4 Process Hazard

The most serious process hazard is the potential for phthalic anhydride dust clouds to

form following process breaches. The condensers will be the primary point of risk but other

equipment; including the storage tanks and the reactor are also possible sources. At low

concentrations (less than 1%), PAN dust is a serious health risk. At higher levels (1.5-10.5%),

PAN dust is a major explosion hazard. A level of 10,000 ppm (1 %) PAN in the atmosphere is

immediately dangerous to life, but a lower concentration also poses a health risk and is an eye,

nose and skin irritant. Health and safety standards require a minimum of 3 ppm PAN and 0.05

ppm MAN for safe working environments before acute or chronic effects are detectable. These

standards will be met through appropriate process design and operating precautions. Phthalic

anhydride dust is explosive at concentrations of 1.5-10.5% in air. As there is always the

possibility of process leaks, all sources of ignition and non-intrinsically safe equipment will be

excluded from the site, except within the main buildings. High-risk zones will be identified and

equipped with air quality monitors to detect dust before it reaches a hazardous level. The three

areas of highest risk are the condensers, reactor and storage vessels. The areas where these items

are located are separated from other items of equipment to prevent an explosion in one area

triggering an explosion in another. Major fires in the plant will burn hot and be difficult to

extinguish, but will not release large quantities of harmful vapours. A fire station, manned by

specially trained process operators, will be located near the process equipment in order to access

and contain any fires before they become difficult to manage.

10.5 Accidental Spills & Tank Breaches

Significant volumes of reactants, products and intermediates will be held on site in the

three product storage tanks, two reactant storage tanks and an intermediate PAN pretreatment

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tank. Spills from these sources are clearly the most serious due to the potential volume of

material that could be lost. Subsequently, all of these vessels require containing walls (or bunds)

to be built around them to prevent loss of hazardous materials in the event of a tank breach.

Ortho-xylene is a flammable and moderately toxic liquid at ambient temperatures and represents

a serious hazard if a significant volume is spilled. Process operations will be paused during a

spill until satisfactory recovery can be completed using temporary storage facilities which will be

readily available on the site. Phthalic anhydride is solid up to 131oC, although it will be held as a

liquid in the main product tanks and intermediate pretreatment tank. Consequently, any spill will

solidify quickly after contact with cool air. This helps to contain spills and aids the recovery

process, but increases the risk of dust cloud formation and may block drains. Recovery can be

affected with shovels and drums, but adequate protective equipment must be provided for the

workers. The recovered product can then be returned to the pretreatment tank to avoid any

discharge to the environment. Hot water will be used to clean up any remaining residue.

10.6 Personal Safety Precautions & Procedures

Safety will be the primary priority for the plant management. The senior operator will

have full authority over the process area and will be required to approve any activities, including

routine maintenance, undertaken in the process area.

Protective equipment will be made available to all employees and a mandatory policy for the use

of safety glasses and hard hats will be implemented. Dust respirators and filters will be available

in the control room at all times. Monitoring programs will be established to ensure that the time-

weighted average daily exposure of workers to PAN or MAN is below the acceptable safety

limits. Similar regulations will apply to visitors. The primary air compressor (providing air feed

to the reactor) is the only loud noise source in the process. Appropriate design modifications will

be made to limit noise from the compressor, and it will be housed in an insulated isolation

enclosure to further restrict noise emissions.

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52

FIGURE: Phthalic anhydride process block diagram with emission sources.

11. PLANT LOCATION

11.1 Plant Location and Site Selection

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The major requirements for an Ethylene Glycol plant are ethylene oxide and water. Glycol plants are almost always located very close to Ethylene oxide plants to reduce transportation expenses, as the transportation of ethylene oxide is expensive due to its explosive tendencies. The plant considered here is located adjacent to an Ethylene oxide plant. The most optimum location would be in a petrochemical industrial area where there is a market for fiber grade glycol.

The other considerations are as follows:

11.1.1 Raw Materials Availability

Probably the location of the raw materials of an industry contributes more toward the choice of plant site than any other factor in most chemical operations low delivered cost of raw materials must be weighed up against other operating costs.This is especially noticeable in those industries in which the raw materials areinexpensive and bulky and is made more compact and obtain a high bulk value during the process of manufacture. The supply of basic raw materials should be controlled directly be user. Physical distance is not the only controlling factor in source of raw materials, for purchase price and buying expense, base point procuring, reserve stock and reliability of supply are also determinants.

11.1.2 Markets and Transportation

The existence of transportation facilities has given too many of the greatest track centers of world. A location should be chosen, if possible which has several competitions will help to maintain low rates and give better service. Often times, a location is selected outside the city in order to have a rail road siding available and thus eliminate trucking costs to freight years from excessive costs of transportation. There will be more long distance water transportation used in the future to reduce the cost of freight years from excessive costs of transportation. There will be long-distance water transportation used in the future to reduce the cost of freight, with the spread between production cost and sales cost constantly narrowing. We would see that the product has a ready market at a close distance from the plant site so that transportation will not become a big problem. Also we have to see that the product has as a ready market so that there will be demand throughout the year for the product.

11.1.3 Climate

The plant site should be at a place where the climate is mild. Excessive cold, torrid heat and excessive humidity should not be present where the plant is situated for this will reduce the productivity part of the workmen. Also if excessive of conditions is present then the air conditioning and other facilities also will increase the expenditure.

11.1.4 Power supply The Chemical Engineering industries are the largest users of electric power equipment among the industries today because the modern demand is for extreme flexibility that sometimes errors on the side of too many individual drives. Power for chemical industry is primarily from

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coal water and oil: in as much as they provide for the generation of steam both for processing and of electricity production. A plant should establish near a hydraulic power generated project. By keeping the availability of power and deep water transportation overweight all other considerations including that of extremely severe winter weather making for difficult operating conditions.

11.1.5 Water supply

Water for industrial purpose can be obtained from one of two general sources: the plant’s own source of municipal supply, if the demand for water is large it is more economical for the industry to supply its own water. Such supply may be obtained from drilled wells, rivers, lakes, dammed steams, or other impounded supplier, before a company enters upon any project, it must ensure itself if a sufficient supply of water for all industrial, sanitary and fire demand, both present and future. Data on temperature of water and on maximum, minimum and average rain fall can be obtained from governmental agencies if surface water is to be pounded or the date on stream flow of reverse can be acquired likewise if wells are to be relied on, Geologists and practical well drillers should be consulted.

11.1.6 Labor supply

A certain careful study of the supply of a cheap labor should be made. Factors to be considered in labor studies are supply, kind diversity, intelligence, wage scales regulation efficiency and costs. The success of many of organizations depends upon the means by which its labor gets to and from their works. A cheap site may have to be avoided if the laborers cone a long distance they will be tired in coming to the plant. Also technical skill should be given due importance.

11.1.7 Community and Site characters

The nature of the sub soil is very important while considering the plant of the industry. Also due consideration should be given for the expansion of the plant. The cost of the land is important, as well as local building costs and living conditions. Also even if there is no immediate plan for expanding, a new plant should be constructed at a location where additional space is available.

11.2 Plant Layout

Plant layout in its broadest sense is a part of the overall system. It includes everything from the original of the building to the location and movement of a small component. It is an integral part of: PRODUCTION PLANNING: It allows, promotes and aids the creation of utility. MAINTENANCE: It affects the amount, difficulty and time required for it. MATERIAL HANDLING: This is necessitated by the design & layout of the plant. ORGANIZATION: Physical layout often determines areas of authority, spheres of personnel influence.

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Obviously machines, equipment, materials, employees, fixtures and all the necessary facilities for engaging in an activity must be given a place of work. How they are located and where they are located, may well determine the firm’s efficiency, its profit potential and its existence. Noise, color, tight and dictate work environment. Proper work environment will increase the productivity to optimum levels, boost the morale and job satisfaction.

Good layout design requires through knowledge of work flow, product flow and information flow. Engineering, management & future expansion are to be imbibed into the layout design. Technology is continuously upgrading making better manufacturing techniques available and correct layout will accommodate these challenges. Consideration is to be given for backward integration and forward integration of the product.

Further the arrangement of the equipment and facilities specified in the process flow sheet is a necessary requirement for accurate pre-construction cost estimation of future detailed design involving piping, structural and electrical facilities. Careful attention to the development of the plot and the elevation plans will point out unusual plant requirements and therefore, give reliable information on building site costs required for precise pre-construction cost accounting.The following list will suggest some of the reasons for what good layout is about:1. Reduce manufacturing costs.2. Increase employee safety.3. Better service to the customer.4. Reduce capital investment.5. Increase flexibility.6. Improve employee morale through improved employee comforts and conveniences in work area.7. Better quality of the product.8. Effective utilization of floor space.9. Reduce work in process to a minimum.10. Reduce work delays and stoppages.11. Better work methods and utilization of labor.12. Improve control and supervision.13. Easier maintenance.14. Reduce manufacturing cycle.15. Better utilization of equipment and facilities.16. Eliminate congestion points.

In developing an effective layout for an enterprise, we should in mind several fundamentals, which exert a significant influence in achieving a good and workable arrangement.

The following are among the major fundamentals most often citied:

11.3 Storage layout

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Storage facilities for raw materials, intermediate and finished products may be located in isolated areas or in adjoining areas. Hazardous materials become a menace to life and property when stored in large quantities and should be kept isolated. Arranging storage of materials so as to facilitate or simplify handling is a point to be considered in design. Where it is possible to pump a single material to an elevation so that subsequent handling can be accomplished by gravity into intermediate reaction storage units.

11.4 Equipment layout

In making layout, ample space should be assigned to each piece of equipment accessibility is an important factor for maintenance. Unless a process is well seasoned, it is not always possible to predict just how its various units may have to be changed in order to be in harmony with each other. It is extremely poor economy to put the equipment layout too closely to a building. A slightly larger building will cost little more than that is crowded. The extra cost will indeed be small in comparison with the penalties that will be extracted if the building was to be extracted. The relative levels of the several pieces of equipment and their accessories determine their placement. Although gravity flow is usually preferable, it is not altogether.

Necessary because liquids can be transported by blowing or by pumping and solids can be moved by mechanical means. Access for initial construction and maintenance is a necessary part of planning, for example, over head equipment must have space for lowering into place, and heat exchange equipment should be located near access areas here trucks or hoists can be placed for pulling and replacing tube bundles. Thus space should be provided for movement of cranes and fork trucks as well as access way around doors and underground hatches. Therefore each plant presents its own challenges that need to be incorporated in the layout.

11.5 Plant expansion

Expansion must always be kept in mind. The question of multiplying the number of units or increasing the size of the prevailing unit or units merit more study than it can be given here. Suffice it to say that one must exercise engineering judgment. Correcting inconsiderate layout plan may involve scrapping the serviceable equipment or shut down the running equipment. Nevertheless the cost of change must be borne for economics of large units and in the end make replacement inevitable.

11.6 Floor space

Floor space mayor may not be major factor in the design of a particular plant. The value of land may be considerable item. The engineer should, however, follow the rule of practicing economy of floor space, consistent with good house keeping in the plant and with proper consideration given to line flow of materials, space to permit working on parts of equipment that need servicing , safety and comfort to the operators.

11.7 Utilities servicing

The distribution of gas, air, water, steam, power and electricity is not always a major item of consideration but flexibility of designing these items should permit to meet almost any

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condition. Regard to the proper placement of each of these services practicing good design reduces the cost of maintenance.

11.8 Workshop

A workshop is also provided to supply tools on demand from laboratory and process. Therefore, this is laid out nearer to the process area.

11.9 Safety units

These are located to the processing area, because probably accidents occur at the processing. Thus they can be easily controlled.

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FIGURE: PHTHALIC ANHYDRIDE PLANT LAYOUT WITH RELEVANT ENVIRONMENT AND SAFETY ADDITION

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