manufacturing of man.pdf

MANUFACTURING OF MALEIC ANHYDRIDE

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Chapter 1

INTRODUCTION


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MALEIC ANHYRIDE

Maleic anhydride (MA) is a versatile monomer and important chemical intermediate.It is

an organic compound with the formula C2H2(CO)2O.Other names for maleic anhydride are 2,5-

furandione, dihydro-2,5dioxofuran,toxilicanhydride, and cis-butenedioic anhydride. Maleic acid

is also called (Z)-2-butenedioic acid, toxilic acid, malenic acid, or cis-1,2-ethylenedicarboxylic

acid.

Maleic anhydride was traditionally manufactured by the oxidation of benzene or

other aromaticcompounds. As of 2006, only a few smaller plants continue to use benzene; due to

rising benzene prices, most maleic anhydride plants now use n-butane as a feedstock:

2 CH3CH2CH2CH3 + 7 O2 → 2 C2H2(CO)2O + 8 H2O

The primary use of MA is in the manufacture of alkyd resins. These resins are added to

fiberglass reinforced plastics to make a strong, lightweight, and corrosion resistantmaterial that is

found in boats, cars, trucks, pipelines and electrical devices. In asecondary capacity, MA is

employed in the manufacture of lacquers, lube-oil additives, and agriculturalproducts. The

addition of MA to drying oils decreases the required drying time and improves the coating

quality of lacquers:dispersants derived from MA prolong oil change intervals and improve the

efficiency of automotive engines. Agriculture productsmade from MA include herbicides,

pesticides, and plant growth regulators.

Furthermore, fumaric and maleic acid are important MA derivatives used in paper sizing resins

and as food and beverage acidulants. Moreover, MA can be used as a starting material for

synthesis of1,4-butanedial.Maleic anhydride (1), maleic acid (2), and fumaric acid(3) are

multifunctional chemical intermediates that find applications in nearly every field of industrial

http://en.wikipedia.org/wiki/Organic_compound

http://en.wikipedia.org/wiki/Organic_oxidation

http://en.wikipedia.org/wiki/Benzene

http://en.wikipedia.org/wiki/Aromatic_compound

http://en.wikipedia.org/wiki/Butane


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chemistry. Each molecule contains two acidcarbonyl groups and a double bond in the α,βposition.

Maleic anhydride and maleic acid are important raw materials used in the manufacture

Of phthalic-type alkyd and polyester resins, surface coatings, lubricantadditives, plasticizers, co-

polymers, and agricultural chemicals.Both chemicalsderive their common names from naturally

occurring malic acid.Other names for maleic anhydride are 2,5-furandione, dihydro-

2,5dioxofuran,toxilicanhydride, and cis-butene dioic anhydride. Maleic acid is also called (Z)-2-

butenedioic acid, toxilic acid, malenic acid, or cis-1,2-ethylenedicarboxylic acid.

TECHNOLOGY STATUS:

IN INDIA:

• The present consumption of MA is, about, 4,200 tonnes per annum and its growing

rate is 11.5%per annum.

• Benzene and normal butane are,the main feed stocks, for maleic anhydride industry.

In India, both the present plants are based on benzene. Presently benzene is in short

supply. In order to bridge this gap, benzene is imported. On the other hand, natural

gas is available in India, in large quantities and normal butane is a constituent of

natural gas. Using butane for production, foreign exchange, spent on benzene can be

saved, while, at the same time, reducing the cost production, of MA.


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INTERNATIONAL:

• The present, global production of MA, is, about 500,000 TPA and the demand growth

rate is, around 5% per annum.

• New catalyst with higher, selectivity, life and stability, have been developed. There is

also, a shift in feed stock, from benzene to butane, because of economics and

pollution control laws. Till recently, fixed bed tubular reactors used to be general

choices for plants. However, recently fluidized bed reactor and transport bed reactors

have been developed and are more suited, for MA production.

INDUSTRIES:

1. Navjyot Chemicals & Commodities Private Limited,Santacruz West, Mumbai,

Maharashtra - 400 054, India

2. Sarvottam Vegetable Oil Refinery Private Limited,Indore, Madhya Pradesh

http://www.indiamart.com/navjyotchemicals/

http://www.indiamart.com/sarvottam-vegetableoil-refinery/synthetic-resin.html


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3. Qinhuangdao Ouke Chemical Co., Ltd.Hebei, China

4. Adarsh Chemicals & Fertilizers Ltd., at Odhna, Gujarat.

5. Allied Aromatics Ltd., at Kalyani, West Bengal.

http://www.made-in-china.com/showroom/chemicaloke


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Chapter 2

LITERATURE SURVEY


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PHYSICAL PROPERTIES:

Physical state : Solid flakes

Appearance : White when in solid form &Colourless in liquid

Odour :acidodour.

Molecular formula :𝐶2𝐻2 (𝐶𝑂)2 𝑂

Molecular weight : 98.06

Melting point : 52.8°C

Boiling point : 202°C

Vapour Density : 3.4 (air = 1)

Density : 1.43gm/cm3 at room temperature

SOLUBILITY

o Water : Insoluble in water

o Acetone at 25°C : 227 g/100 g

o Ethyl acetate : 112 g/100 g

o Chloroform : 52.5 g/100 g

Sp.gravity :1.48 (at 20° C/20 °C solid)

1.3 (at 70° C/70° C molten)

Auto ignition temperature : 447°C

Flash point :

o Open Cup 110 °C (230° F)

o Closed Cup 102° C (216° F)


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CHEMICAL PROPERTIES:

Formation of acid by hydration:

Molten maleic anhydride reacts exothermally & rapidly with liquid water to formthe

maleic acid.

+ H20 →

Maleic Esters from Alcohols:

Maleic anhydride has been converted into a range of acrylate esters on treatment

with a suitable alcohol using triphenylphosphine as a catalyst. Maleic anhydride reacts

with unhindered alcohols to provide acrylate esters in a process catalyzed by

triphenylphosphine.

Sulfonation:

Maleic anhydride is sulfonated to a-sulfomaleic anhydride with sulfur trioxide.

+ SO3 →


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Alkylation of Maleic Anhydride: Normal alpha olefins and maleic anhydride react to form

alkenyl succinic anhydrides

Electrophilic Addition: Electrophilic reagents attack the electron-deficient bond of maleic

anhydride. Typical addition reagents include halogens, hydrohalic acids, and water.

Esterification: Both mono - and dialkyl maleates and fumarates are obtained on treatment of

maleic anhydride or its isomeric acids with alcohols or alkoxides . An extensive review is

available. Alkyl fumarates often are made from isomerization of the corresponding maleate.


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APPLICATIONS:

1. Alkyd resins: The largest single end use of maleic anhydride is the preparation of alkyd

resins. About 95% of alkyd resins are used in surface coatings. They have some

desirable properties such as “Quick Dry” characteristics, outstanding weather &

exposure resistance, flexibility& excellent adhesion to the surface to be protected.

2. Plasticizers: The second largest use of maleic anhydride is the production of plasticizers

of various synthetic resins or plastics. Most of the maleic esters end up in the Di-butyl

maleate co-onomer. These are used Lube oil additives, textile finishing agents,

Ingredient in bonding agents used to manufacture plywood. Used in the manufacture of

coating resins and polyester resins for plastics.

3. Dyes &intermediates: The third largest end use of maleic anhydride is in the

preparation of various classes of dyes & intermediates. The most important are the2(p-

N,N-dimethyl-amino-phenyl)-3-nitromaleic anhydride. It is done by condensation

reaction between maleic anhydride with 4-flouoroanisole.

4. Retarders: It is also used as a retarder in rubbers, retarders are the ingredients used to

protect against scratch hazard.

5. Metallic & acid salts: Maleic anhydride is also used in the manufacture of metallic

salts & acids such as sodium salt etc.

6. Pharmaceuticals: Maleic anhydride is also used in the preparation of some

pharmaceuticals such as Pyran.

7. Agriculture: Maleic anhydride is also used in the preparation of maleic hydrazine

&Endothall salt for improving the fertility of soil.


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STRUCTURE OF MALEIC ANHYDRIDE:

From the single crystal x-ray data, Maleic anhydride is a planar molecule with the ring oxygen

atom lying 0.003 nm out of the molecular plane. A twofold rotation axis bisects the double bond

& passes through the ring oxygen atom.

Bond distances in nm for the structure of maleic anhydride is determined by single crystal x-ray

diffraction methods at 110K.The maleic anhydride molecule is nearly planar. The plane

containing the 𝑂1 ,𝐶4 and 𝐶5 atoms has no other atomic nuclei in the molecule deviating from the

plane by more than 0.0036 nm.

HANDLING AND STORAGE:

Maleic Anhydride must be stored in a cool, dry, well ventilated area.

Areas where there is high potential risk of fires must be avoided. Outdoor or detached

storage is preferable.

The material should be separated from other storage, especially from alkali metals or

amines.

It must be very well protected from moisture and oxidizing materials.


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PRECAUTIONS:

Maleic Anhydride is a powerful irritant, in contact it causes conjunctivitis ,cornea damage,

nausea, headaches, pulmonary edema and dermatitis.

Personnel must not be exposed to the concentrated vapours.

Protective clothing, chemical goggles, gloves and if necessary gas mask should be worn

when handling the material.

SHELF LIFE:

3 Months from date of production .

NB : Due to the effect of atmospheric moisture on Maleic Anhydride the solidification point may

be decreased and the Maleic Acid content may exceed the limit quoted if the material is stored for

a lengthy period under humid conditions.

SHIPMENT:

Molten maleic anhydride is shipped in tank rail cars, tank trucks, and isotanks (for overseas

shipments). Tank rail cars are typically constructed of lined carbon steel and are insulated and

equipped with steam coils. Tank rail cars of up to 20k gallons are used. Tank trucks are typically

constructed of stainless steel, insulated, and equipped with steam coils. Tank trucks of up to 4.5k

gallons are used. Isotanks are typically constructed of stainless steel and are insulated and equipped

with steam coils. Isotanks of up to 4.5k gallons are used.

PACKAGING:

Bags 25 Kg ( 40 bags per pallet )

Typical bag construction is either polyethylene or multi-ply paper with at least one polyethylene

layer. Solid form maleic anhydride can be stored in bags for several months in a cool, dry

location.


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Chapter 3

VARIOUS TYPES OF PROCESSES


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PROCESS TECHNOLOGY EVOLUTION:

Maleic anhydride was first commercially produced in the early 1930s by the vapor-phase oxidation of

benzene . The use of benzene as a feedstock for the production of maleic anhydride was dominant in the

world market well into the 1980s. Several processes have been usedfor the production of maleic

anhydride from benzene with the most common one from Scientific Design. Small amounts of maleic

acid are produced as a by-product in production of phthalic anhydride.

There are two types of processes available for the manufacturing of maleic anhydride.

1. BENZENE BASED PROCESSES.

2. BUTANE BASED PROCESSES.

1. BENZENE BASED TECHNOLOGIES:

The catalyst used for the conversion of benzene to maleic anhydride consists of supported

vanadium oxide. The support is an inert oxide such askieselguhr, alumina ,or silica and is of low

surface area. Supports with higher surface area adversely affect conversion of benzene to maleic

anhydride. The conversion of benzene to maleic anhydride is a less complex oxidation than the

conversion of butane, so higher catalyst selectivity’s are obtained. The vanadium oxide on the

surface of the support is often modified with molybdenum oxides. There is 70%

vanadium oxide and 30% molybdenum oxide in the active phase for these fixed-bed catalysts.

The molybdenum oxide is thought to form either a solid solution or compound oxide with the

vanadium oxide and result in a more active catalyst .

a) BENZENE BASED FIXED BED PROCESS TECHNOLOGY:

The benzene fixed-bed process is very similar to the butane fixed-bed process and, in fact,

the Scientific Design butane process has evolved directly from its benzene process.

Benzene-based processes are easily converted to butane-based processes. Typically, only a

catalyst change, installation of butane handling equipment, and minor modifications to the

recovery process are required. The benzene reaction is a vapour-phase partial oxidation reaction


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using a fixed-bed catalyst of mixed vanadium and molybdenum oxides. The reactors used are the

same multi tubular reactors cooled by circulating a molten mixture of 𝐾𝑁𝑂3 –𝑁𝑎𝑁𝑂2 –

𝑁𝑎𝑁𝑂3saltsdescribed in the section on the butane process. The benzene concentrations

used are 1.5 mol% or just below the lower flammable limit of benzene in air. Unlike the butane

reaction, the reactor normally operates at conversions>95% and molar yields >70%. The benzene

oxidation reaction runs a little cooler than the butane oxidation reaction, with typical reactor

temperatures in the350–400°C range. The reactor off-gas is cooled by one or more heat

exchangers and sent to the collection and refining section of the plant. Unreacted benzene and

by-products are incinerated.

BUTANE BASED TECHNOLOGIES:

The increased importance of the butane-to-maleic anhydride conversion route has resulted in

efforts being made to understand and improve this process. Since 1980,over 225 U.S.

patents have been issued relating to maleic anhydride technology. The predominant area of

research concerns the catalyst because it is at the heart of this process. The reasons for this

statement are twofold. First, there is the complexity of this reaction: for maleic anhydride to be

produced from butane, eight hydrogen atoms must be abstracted, three oxygen atoms inserted,

and a ring closure performed. This 14-electron oxidation occurs exclusively on the surface of the

catalyst. The second reason for the emphasis placed on the catalyst is that all the

commercial processes use the same catalyst. This catalyst is the only commercially

viable system that selectively produces maleic anhydride from butane. The catalyst used in the

production of maleic anhydride from butane is vanadium–phosphorus oxide (VPO). Several

routes may be used to prepare the catalyst.

In different industrial processes, the oxidation of n- butane differs in the type of reactor, type of

recovery and type of purification.


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There are three types of reactors which are used for the production of maleic anhydride:

• Multi Tubular Fixed bed Reactors

• Fluidised-bed Reactors and

• Transport bed reactors.

The main difference between the individual recovery sections is the choice of an aqueous or an organic

solvent. The purification (if necessary) is carried out by means of batch distillation or continuous

distillation. Unreacted n-butane is mostly burnt to carbon oxides.

a) BUTANE BASED FIXED BED PROCESS TCHNOLOGY:

Maleic anhydride is produced by reaction of butane with oxygen, using the vanadium–

phosphorus oxide heterogeneous catalyst. The butane oxidationreaction to produce maleic

anhydride is very exothermic. The main reaction byproducts are carbon monoxide and carbon

dioxide.

Stoichiometry and heat of reaction for the three principal reactions are as follows:

C4H10 + 3.5 O2 C4H2O3 + 4 H2O ∆H 1236 kJ/mol (295.4 kcal/mol)

C4H10 + 6.5 O2 4 CO2 + 5 H2O∆H 2656 kJ/mol (634.8 kcal/mol)

C4H10 + 4.5 O2 4 CO + 5 H2O∆H 1521 kJ/mol (363.5 kcal/mol)

Air is compressed to modest pressures, typically 100–200 kPa (15-30 psig) and 350-450°C with

either a centrifugal or radial compressor, and mixed with superheatedvaporized butane. Static

mixers are normally employed to ensure good mixing. Butane concentrations are often limited to

<1.7 mol% to stay below the lowerflammable limit of butane.The highly exothermic nature of

the butane-to-maleic anhydride reactionand the principal by-product reactions require substantial

heat removal fromthe reactor. Thus the reaction is carried out in what is effectively a large

multitubular heat exchanger that circulates a mixture of 53% potassium nitrate 𝐾𝑁𝑂3,

40% sodium nitrite ,𝑁𝑎𝑁𝑂2; and 7% sodiumnitrate, 𝑁𝑎𝑁𝑂3.


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Despite the rapid circulation of salt onthe shell side of the reactor, catalyst temperatures can be

40–608°C higher thanthe salt temperature. The butane-to maleic anhydride reaction typically

reachesitsmaximum efficiency (maximum yield) at 85% butane conversion.Reactor operation at

80–85% butane conversion to produce maximum yields provides an opportunity for recycle

processes to recover the unreactedbutane in the stream that is sent to the oxidation reactor.

b) BUTANE-BASED FLUIDIZED-BED PROCESS TECHNOLOGY:

Fluidized bed processes offer the advantage of excellent control of hot spots by rapid catalyst

mixing, simplification of safety issues when operating above the flammable limit, and a

simplified reactor heat-transfer system. Some disadvantages include the effect of back mixing on

the kinetics in the reactor, product destruction and by-product reactions in the space above the

fluidized bed, and vulnerability to large-scale catalyst releases from explosion venting.

Compressed air and butane are typically introduced separately into the bottom of the fluidized-

bed reactor. Heat from the exothermic reactionis removed from the fluidized bed through steam

coils in direct contact withthe bed of fluidized solids. Fluidized-bed reactors exploit the

extremely highheat-transfer coefficient between the bed of fluidized solids and the steamcoils.

This high heat-transfer coefficient allows a relatively small heat-transfer area in the fluid-bed

process for the removal of the heat of reaction in comparisonto the fixed-bed process. The

product stream contains gases and solids. The solids are removed by using either cyclones,

filters, or both in combination. Fluidized-bed reaction systems are not normally shut down for

changing catalyst. The process includes facilities for adding back both catalyst fines and fresh

catalyst to the reactor.

c) BUTANE-BASED TRANSPORT-BED PROCESS TECHNOLOGY:

Du Pont announced the commercialization of a moving-bed, recycle-based technology for

the oxidation of butane to maleic anhydride. Athoughmaleic anhydride is produced in the

reaction section of the process and could be recovered, it is not a direct product of the process.

Maleic anhydride is recovered as aqueous maleic acid for hydrogenation to Tetrahydrofuran. The


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reaction technology known as transport bed is a circulating solids technologyin which the

oxygen required in the oxidation of butane to maleic anhydride is provided by the VPO catalyst

and the catalyst is reoxidized in a separate step. Fresh butane mixed with recycled gas encounters

freshly oxidized catalyst at the bottom of the transport-bed reactor and is oxidized to maleic

anhydride and Coxduring its passage up the reactor. Catalyst densities (80-160 kg/𝑚3) in the

transport-bed reactor are substantially lower than the catalyst density in a typical fluidized-bed

reactor (480-640 kg/𝑚3). The gas flow pattern in the riser is nearly plug flow which a voids the

negative effect of back mixing on reaction selectivity. Reduced catalyst is separated from the

reaction products by cyclones and is further stripped of products and reactants in a separate

stripping vessel. The reduced catalyst is re oxidized in a separate fluidized-bed oxidizer where

the exothermic heat of reaction is removed by steam coils. The rate of re oxidation of the VPO

catalyst is slower than the rate of oxidation of butane, and consequently residence times are

longer in the oxidizer than in the transport-bed reactor.Maleic anhydride in the product stream is

removed and converted to a maleic acid solution in a waterscrubbing system. The maleic acid is

sent to the hydrogenation to produce THF while the reactor off-gasafter scrubbing is sent to the

recycle compressor. A small purge stream is sent to incineration.


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MERITS AND DEMERITS OF BUTANE AND BENZENE AS RAW MATERIAL:

BUTANE

MERITS:

It is cheaply available as compared to

benzene.

The butane can be easily recovered

from natural gas.

Energy required is less as compared to

that for benzene process.

Not a hazardous product.

Proven, safe design that provides for

long-term, high, stable reactor

performance.

Lower air requirements as compared

with fixed-bed technology, which allows

for lower capital investment cost and

ongoing energy requirements for new

build plants.

Lower maintenance costs and higher

reliability (greater than 99% on-stream

time) as compared to fixed-bed

BENZENE

MERITS:

Benzene gets Easily oxidized.

High selectivity for feedstock


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processes.

Ability to scale to higher production

capacities with a single reactor

system.

DEMERITS:

There is a complexity of reaction.

Causes abrasion of the catalyst.

Conversion rate is low.

By product formation

DEMERITS:

Inefficient feedstock because of

removal of two excess carbon atom

present in benzene ring.

Rapid increase the cost of benzene.

Considered as hazardous material.

Large energy inputs are required


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SELECTION CRITERIA FOR MANUFACTURING OF MALEIC ANHYDRIDE:

The abundance and low cost of light alkanes have generated in recent yearsconsiderable interest

in their oxidative catalytic conversion to olefins, and nitriles inpetroleum and petrochemical

industries. One of the most fascinating and unique catalytic processes is the 14- electrons

selective oxidation of n-butane to maleic anhydride (2,5-furandione) by vanadyl phosphates. It

is the only industrial process of selective vapor- phase oxidation of an alkane that uses the

dioxygen. Since 1974, n-butane has been increasingly usedinstead of benzene as the raw

material for maleic anhydride production.At present more than seventy percent of maleic

anhydride is produced from n-butane.Many studies on n-butane oxidation by vanadyl phosphate

catalysts indicate that crystalline vanadyl(IV) pyrophosphates are present in the most selective

oxidation of n-butane to maleic anhydride. From a raw material viewpoint, the relatively low

purchase price of C4 is much more attractive than the expense of benzene. Other influential

factors that favor C4s are safety, health, and the environment.Benzene is a known carcinogen

and one of the chemicals most stringently regulated by the government. The flammability limits

for 𝐶4 HC are also lower than those for benzene, which is an additional safety advantage of the

process. For all of these reasons, the fixed-bed process with n-butane has been the only MA route

used commercially since 1985 in the United States.

The advantages of a fluidized-bed reactor over a packed bed are claimed to be the following:

• Avoids hot spots.(Fluidized beds are nearly isothermal because the heat capacity of the

solid catalyst particles far exceeds that of the gas, and because the solids circulate.)

• Enables use of separate feed streams for n-butane and air, so that one can operate overall

within the combustible range.This reduces the air requirement, the compressor size and

power, the reactor size,and the size of the downstream separation equipment, and permits

use of an incinerator for the waste gas with production of valuable steam.

• Cost is much lower than for tubular reactors cooled by a molten salt.

• Easy to load and unload.

• Can generate valuable steam while cooling the reactor.


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Chapter 4

PROCESS DESCRIPTION


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Raw material: Butane, Oxygen.

Catalyst: Vanadium phosphorus oxide (VPO)

By product: fumaric acid, carbon di oxide, carbon monoxide,

Type of reactor: Fluidized bed reactor.

Properties of butane:

• Molecular weight : 58.123 g/mol

Solid phase

• Latent heat of fusion (1,013 bar, at triple point) : 80.165 kJ/kg

Liquid phase

• Liquid density (1.013 bar at boiling point) : 601.4 kg/m3

• Liquid/gas equivalent (1.013 bar and 15 °C (59 °F)) : 239 vol/vol

• Boiling point (1.013 bar) : -0.5 °C

• Latent heat of vaporization (1.013 bar at boiling point) : 385.6 kJ/kg

Critical point

• Critical temperature : 152 °C

• Critical pressure : 37.96 bar

Gaseous phase

• Gas density (1.013 bar at boiling point) : 2.7 kg/m3

• Gas density (1.013 bar and 15 °C (59 °F)) : 2.52 kg/m3

• Compressibility Factor (Z) (1.013 bar and 15 °C (59 °F)) : 0.9625

• Specific gravity (air = 1) (1.013 bar and 21 °C (70 °F)) : 2.076

• Specific volume (1.013 bar and 21 °C (70 °F)) : 0.4 m3/kg

• Heat capacity at constant pressure (Cp) (1.013 bar and 25 °C (77 °F)) : 0.096 kJ/(mol.K)

• Heat capacity at constant volume (Cv) (1.013 bar and 15.6 °C (60 °F)) : 0.088 kJ/(mol.K)

• Viscosity (1.013 bar and 0 °C (32 °F)) : 0.0000682 Poise

• Thermal conductivity (1.013 bar and 0 °C (32 °F)) : 13.6 mW/(m.K)


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PROCESS: Pure butane and compressed air (100 to 200 KPa) at 350-400°C,are mixed and fed to fluidized

bed reactor, where butane reacts with oxygen to form maleic anhydride. Air is compressed to

modest pressures, with either a centrifugal or radial compressor. Heat from the exothermic

reaction is removed from the fluidized bed through steam coils in direct contact with the bed of

fluidized solids. Fluidized-bed reactors exploit the extremely high heat-transfer coefficient

between the bed of fluidized solids and the steam coils. This high heat-transfer coefficient allows

a relatively small heat transfer area in the fluid-bed process for the removal of the heat of

reaction compared to the fixed-bedprocess.Fluidized-bed reaction systems are not normally shut

down for changing catalyst. Fresh catalyst is periodically added to manage catalyst activity and

particle size distribution. The process includes facilities for adding back both catalyst fines and

fresh catalyst to the reactor.

The product stream contains gases and solids. The solids are removed by using either cyclones,

filters, or both in combination. Cyclones are devices used to separate solids from fluids using

vortex flow. The product gas stream must be cooled before being sent to the collection and

refining system. The process uses cyclones as a primary separation technique with filters

employed as a final separation step after the off-gas has been cooled and before it is sent to the

collection and refining system .

The reactor off-gas which is separated from solids is cooled from reaction temperatures in a gas

cooler upwith generation of steam. The off-gas is then sent to a tempered water-fed after cooler,

where it is cooled below the dew point of maleic anhydride. The liquid droplets of

maleicanhydride are separated from the off-gas by a separator. The condensed crude is pumped

to a crude tank for storage.

The maleic anhydride remaining in the gas stream after partial condensation is removed in

awater scrubber by conversion to maleic acid which accumulates in the acid storage section at

the bottom of the scrubber. The acid solution is converted to crude maleic anhydride in a dual

purpose dehydrator/stripper.Xylene is used as an azeotropic agent for the conversion of maleic

acid to maleic anhydride.Water from the dehydration step is recycled to the scrubber.


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When the conversion of the acid solution to crude maleic anhydride is complete, condensed

crude maleic anhydride is added to the still pot and a batchdistillation refining step is conducted.

In the distillation column, maleic anhydride and water are separated. The distillate, is sent to

waste treatment and the bottoms, consists of 99-wt% maleic anhydride.

CATALYST:

Unsupported vanadium phosphorus oxide (VPO) catalysts are preferred for the fixed bed as well

as fluidized bed reactors. Promoters such as lithium, zinc, and molybdenum are commonly

used. Recent research has shown that Mg, Ca, and Ba ions are also effective promoters,

generating higher conversion, yield, and selectivity than the unmodified VPO catalyst.The ratio

of phosphorus to vanadium determines the activity of the catalyst, and, in turn, the life. Catalyst

activity is greater at high phosphorus-vanadium ratios, but the catalyst life is sacrificed as the

activity increases. A phosphorus-vanadium ratio of 1.2 in the catalyst appears to provide the

optimal balance between activity and catalyst life.

Only the surface layers of the catalyst solid are generally thought to participate in the reaction.

This implies that while the bulk of the catalyst may have an oxidation state of 4+ under reactor

conditions, the oxidation state of the surface vanadium may be very different. It has been

postulated that both V4+ and V5+ oxidation states exist on the surface of the catalyst, the latter

arising from oxygen chemisorption. Phosphorus enrichment is also observed at the surface of the

catalyst. The exact role of this excess surface phosphorus is not well understood, but it may play

a role in active site isolation and consequently, the oxidation state of the surface vanadium.

Preparation of the catalyst begins by mixing the V-P with nearly anhydrous phosphoric acid and

an organic solvent. Next, the mixture is heated and the organic solvent is removed by

volatilization. The product is dried and calcined to yield the catalyst precursor, which is then

pelletized or formed into spheres. Finally, the catalyst is loaded into the reactor where it is

activated under carefully controlled conditions.


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SAFETY FACTORS:

Inhalation:

Remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give

oxygen. Call a physician.

Ingestion:

Induce vomiting immediately as directed by medical personnel. Never give anything by mouth to

an unconscious person.

Skin Contact:

In case of contact, immediately flush skin with plenty of soap and water for at least 15 minutes

while removing contaminated clothing and shoes. Wash clothing before reuse. Call a physician

immediately.

Eye Contact:

Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper

eyelids occasionally. Get medical attention immediately.

Accidental Release Measures

Remove all sources of ignition. Ventilate area of leak or spill. Wear appropriate person a

protective equipment as specified in Section 8. Spills: Clean up spills in a manner that does not

disperse dust into the air. Use non-sparking tools and equipment. Reduce airborne dust and

prevent scattering by moistening with water. Pick up spill for recovery or disposal and place in a

closed container. Evacuate area of all unnecessary personnel. US Regulations (CERCLA) require

reporting spills and releases to soil, water and air in excess of reportable quantities.

Personal Respirators (NIOSH Approved):

If the exposure limit is exceeded, and engineering controls are not feasible, a full-face piece

respirator with an organic vapor cartridge and particulate filter (NIOSH type N100 filter) may be

worn up to 50 times the exposure limit, or the maximum use concentration specified by the

appropriate regulatory agency or respirator supplier, whichever is lowest. If oil particles (e.g.

lubricants, cutting fluids, glycerine, etc.) are present, use a NIOSH type R or P particulate filter.


28

FIRE FIGHTING MEASURES :

Flash point: 102°C (216°F)

Auto ignition temperature: 477°C (891°F)

Fire Extinguishing Media:

Alcohol foam, carbon-dioxide. DO NOT USE dry chemical, multipurpose dry chemical, or

loaded stream media because of explosion potential due to reactivity of basic compounds in these

extinguishing media.

ENVIRONMENTAL HAZARDS:

Environmental Fate:

When released to air, soil and water; maleic anhydride will probably hydrolyze to maleic acid

and be processed as follows.

When released into the soil, this material is expected to leach into groundwater. When released

into thesoil, this material is expected to readily biodegrade.

When released into water, this material is expected to readily biodegrade. When released into

water, this material is not expected to evaporate significantly.

When released into the air, this material is expected to exist in the aerosol phase with a short

half-life. When released into the air, this material is not expected to be subject to wet deposition.

When released into the air, this material is expected to bedegraded by reaction with ozone and

photochemically produced hydroxyl radicals. This material is not expected `to significantly

bioaccumulate. This material has an estimated bioconcentration factor (BCF) of less than 100.

Environmental Toxicity:

When released to soil and water; maleic anhydride will probably hydrolyze to maleic acid and be

represented bythe following data for maleic acid.

TLm /Fathead minnow/5ppm/96 hr./fresh water.


29

TLm/Mosquito fish/240 ppm/24-48 hr./fresh water.

Chronic Toxicity:

Inhalation reference exposure level:

0.7 µg/m

3

(2.5 ppb)

Critical effect:

Neutrophilic infiltration of the nasal epithelium;

irritation of the respiratory system in rats,hamsters and monkeys

Hazard index target:

Respiratory system


30

Chapter 5

THERMODYNAMICS & KINETICS OF PROCESS


31

The knowledge of thermodynamics help us to identify whether the given chemical reaction may

occur spontaneously & to assist how far the reaction will proceed.

As most of the chemical reactions are accompanied by evolution or absorption of heat, heat

formation, entropy & free energy are some vital items of thermodynamics. Thermodynamics

help us to calculate the free energy of reaction which shows whether the reaction is feasible at

given temperature or not.

The free energy change for a process is denoted as ΔG0.

For manufacture of maleic anhydride from feed stock of n-butane, the reaction consists of vapour

phase oxidation of n-butane to give maleic anhydride & water.

C4H10 + 3.5O2 → C4H2O3 + 4H2O

For this process, we have to find out the free energy of reaction at reaction conditions. By

combining Gibb’s helmoltz equation & integrated Vanthoff’s equation as.

ΔG0 = -RTlnk

CALCULATION OF GIBBS ENERGIES OF MALEIC ANHYDRIDE:

Groups No.of Groups ΔG298(KJ/mole)

CO2

1

-394.38

CO

1

-137.27

C2H2

1

209.9


32

ΔG298=ΔG273+ ΔGn1

ΔG298 = 60.98+ (-394.38-137.27+209.9)

ΔG298 = -260.77 KJ/Kmole

for Butane,

ΔG298 = -115.26KJ/Kmole

For Water,

ΔG298 = -228.5 KJ/mole

ΔG298 = ΣΔGproduct – ΣΔGreactant

= -260.77 + (4x-228.59) – 115.26 +(3.5x0)

ΔG298= -1059.51 KJ/Kmole

CALCULATING ΔΗR0

For maleic anhydride,

ΔΗR0 = - 469.8 KJ/Kmole

For Butane,


For Water



33

For enthalpy change taking place at 2980k is given as

ΔΗR0 = Σ (ΔΗ298) product – Σ (ΔΗ298) reactant

ΔΗR0 = [(-469.8) + 4x (-241.82)]- [(-125.6) + (3.5x -279.9)]

ΔΗR0 = -331.83 KJ /Kmole

Also, ΔΗR0 is given by the reaction,

ΔΗR0 = ΔΗ0

0 + ΔaT + ΔbT2/2 + ΔcT3/3 + ΔdT4/4

For the reaction,

C4H10 + 3.5O2 → C4H2O3 + 4H2O

Δa = aMAN + 4aH2O – (aC8H10 + 3.5aO2)

Similarly, we can calculate Δb,Δc,andΔd.

Δa = [(-13.07) + 4(32.49)]– [(-2.4511)+( 3.5x26.025)]

Δa = 28.244

∆b = ∆bman + 4∆bH20 - ∆bC4H10 + ∆bo2

[3.483 x 10-3 + (4x0.0796 x 10-3) ]– [(391.82x 10-3) + (3.5 x 11.75x 10-3)]

Δb = -0.43296

∆c = ∆cMAN + ∆cH2o - ∆cC4H10 + ∆c02

∆c = 0.2187 x 10-6 + (4x 13.2107 x 10-6) – [(-202.98 x 10-6) + (3.5 x -2.34 x 10-6)

Δc = 2.6423 x 10-4


34

Since Δd is very small so we neglect it ,

Substituting in the above equation,

-1059.51 = ΔΗ00 + [28.24x(298)]- [0.4329x(298)2/2 ]+ [2.6423x10-4x(298)3/3]

ΔΗ00 = 7417.79 KJ/Kmole

From the integrated Vant Hoff’s Equation & Gibbs Helmoltz’s Equation, we get,

ΔG° = = ΔH00 + ΔaT + ΔbT2/2 + ΔcT3/3 + ΔdT4/4 + I(T)

Where I = Integration constant

1059.51 = 7417.79 + [28.24x(ln 298)x(298)] –[0.4329x(298)2/2 ]+ [2.6423x 10-4x(298)3/6 ]+

I(298)

I = -128.41

At reaction temperature, i.e. 673K

ΔG673 = 7417.79+ [28.24x(ln 673)x (673)] – [0.4329x(673)2/2] + [2.6423 x 10-4x(673)3/6 ]–

[128.41x(673)]

ΔG673 = - 39852.14 KJ/Kmole

This shows that the reaction is thermodynamically feasible at reaction temperature,

From Gibbs Equation,

ΔG0 = -RTlnk

- 39852.14 = -8.314 x 673 x lnk

k = 1.2394x103


35

Chapter 6

MATERIAL BALANCE


36

Basis : 3 Tons/day of pure Maleic Anhydride is produced

According to us patent #4317778 air is provided in the ratio

Bu : O2

1 : 8.65

From Encyclopedia,

Butane unreacted = 17%

Butane converted to maleic anhydride = 73%

Butane converted to acrylic acid = 1.1%

Butane converted to formic acid = 1.07%

Maleic anhydride produced = 123 kg/hr

= 1.255 kmole/hr

Assuming 3% loss ( 2% in scrubber & 1% in distillation column)

Maleic anhydride to be produced = 127 kg/hr

= 1.306 kmol/hr

Consider the reaction

C4H10 + 3.5 O2C4H2O3 + 4H2O

1 kmole of butane = 1 kmole of Maleic anhydride

= 1.306 kmole of Maleic anhydride

Butane reacted = 1.306 kmole/hr

= 75.74 kg/hr


37

= 75.74 kg/hr

Butane supplied = 75.74\0.73

= 103.75 kg/hr

= 1.78 kmole/hr

O2 required = 3.5 * 1.78

= 6.23 kmole/hr

= 199.36 kg/hr

O2 supplied = 6.23 * 8.65

= 53.88 kmole/hr

= 1724.464 kg/hr

N2 supplied = 1724.464 * (0.79/0.21)

= 5748.25 kg/hr

= 205.3 kmole/hr

Total dry air = 7472.714 kg/hr

= 257.67 kmole/hr

H2O with air = 7427.714 * 0.03

= 222.83 kg/hr

= 7.683 kmole/hr


38

Input to reactor

components Kg/hr Kmole/hr

N2 5748.25 205.3

O2 1724.464 53.88

C4H10 103.75 1.788

H2O 0 0

Total 7575.25 260.96

So butane unreacted = 0.17 * 1.78

= 0.3206 kmole/hr

= 17.56 kg/hr

Butane converted to Maleic anhydride = 0.73 * 1.78

= 1.3 kmole/hr

= 127.34 kg/hr

Butane converted to Acrilic acid = 0.011 *1.78

= 0.019 kmole/hr

= 1.409 kg/hr

Butane converted to formic acid = 0.0107 * 1.78

= 0.019046 kmole/hr

= 0.5713 kg/hr


39

Total butane in – butane consumed = butane coming out of reactor

1.78–(1.3 + 0.019 + 0.019046 + X) = 0.3206

Where X is the amout of butane available for COx

X = 0.1213 kmole/hr

= 7.038 kg/hr

Reactions

C4H10 + 3.5 O2 C4H2O3 + 4H2O ------------- (1)

C4H10 + 5.5 O2 2CO2 + 2CO + 5H2O --------------(2)

C4H10 + 3.5 O2 C3H4O2 + CO2 + 3H2O -------------(3)

C4H10 + 6 O2 CH2O + 3CO2 + 4H2O -------------------- (4)

O2 Balance:-

O2 consumed in reaction (1) = 3.5 * 127.34

= 445.69 kg/hr

= 13.92 kmole/hr

O2 consumed in reaction (2) = 5.5 * 7.038

= 38.709 kg/hr

= 1.209 kmole/hr

O2cosumed in reaction (3) = 3.5 * 1.409

= 4.9315 kg/hr

= 0.154 kmole/hr


40

O2 consumed in reaction (4) = 6* 0.5713

= 3.4278 kg/hr

= 0.1711 kmole/hr

O2 unreacted = O2 feed – O2 consumed

= 1724.464-(445.69 + 38.709 + 4.9315 + 3.4278)

= 1231.705 kg/hr

= 38.49 kmole/hr

CO2 balance:

CO2 produced in reaction (2) = 2 * 7.038

= 14.076 kg/hr

= 0.3199 kmole/hr

CO2 produced in reaction (3) = 1.409 kg/hr

= 0.0320 kmole/hr

CO2 produced in reaction (4) = 3* 3.4278

= 10.283 kg/hr

= 0.233 kmole/hr

Total CO2 produced = 26.398 kg/hr

= 0.599 kmole/hr


41

CO Balance:

CO produced in reaction (2) = 2 * 7.038

= 14.076 kg/hr

= 0.3199 kmole/hr

H2O Balance:-

H2O produced in reaction (1) = 4 * 127.34

= 509.36 kg/hr

= 28.29 kmole/hr


= 35.19 kg/hr

= 1.955 kmole/hr


= 4.227 kg/hr

= 0.2348 kmole/hr


= 2.285 kg/hr

= 0.1296 kmole/hr

Total H2O produced = 30.61 kg/hr

Total H2O at outlet = 30.61 kg/hr = 1.7kmole/hr


42

Output from the Reactor:

Component Kg/hr Kmole/hr

N2 5748.25 205.3

O2 724.46 22.64

H2O 30.61 1.7

CO2 26.398 0.59

C4H2O3 127.34 1.3

CO 14.076 0.525

C4H10 17.56 0.3027

CH2O 0.5713 0.01904

C3H4O2 11.53 0.1601

Total 6717.07 232.16


43

AROUND COOLER

In gas cooler the gas is cooled up to dew point f maleic anhydride up to 120°C and it is send to

separator for separating gas & liquid

Input = output

6717.07 kg/hr = 6717.07 kg/hr

SEPERATOR:-

In a separator 40% of maleic anhydride , 2 % of water , 1% of formic acid which is condensed

get separated at bottom which is Stored in crude tank while the gas goes for further process.

Maleic anhydride condensed = 0.4 * 127.34

= 50.936 kg/hr

= 0.519 kmole/hr

Water condensed = 0.02 * 30.61

= 0.6122 kg/hr

= 0.0340kmole/hr

Formic acid condensed = 0.01 * 0.5713

= 0.005713 kg/hr

= 0.0001904kmole/hr


44

Composition of bottom stream:

Components Kg/hr Kmole/hr

Maleic anhydride 50.936 0.519

Water 0.6122 0.0340

Formic acid 0.005713 0.0001904

Total 56.009 0.8008

Composition of top stream:

Component Kg/hr Kmole/hr

N2 5748.25 205.3

O2 724.46 22.64

H2O 29.998 1.667

CO2 26.398 0.59

C4H2O3 76.404 0.7796

CO 14.076 0.525

C4H10 17.56 0.3027

CH2O 0.5655 0.0188

C3H4O2 11.53 0.1601

Total 6647.79 232


45

AROUND SCRUBBER

Absorption is done by using water as a solvent. Let 1% of maleic anhydride produced is lost in

vent stream & all butane while formic acid leaves the scrubbed liquid.

Maleic anhydride lost = 0.01 * 76.404

= 0.76404 kg /hr

Maleic anhydride converted to maleic acid = (76.404 – 0.76404)

= 75.64 kg/hr

Assuming liquid to vapour ratio as 1.2

G = 6647.79 kg/hr

L= 6647.8 * 1.2

= 7977.336 kg/hr

H2O lost= 7977.336-75.64

= 7901.696 kg/hr

= 438.983 kmole/hr

Maleic acid produced = 75.64 kg/hr

Maleic acid leaving stream= 75.64 kg/hr


46

Total moles in vent stream excluding water


N2 5748.25 205.29

O2 724.46 22.64

CO2 19.93 0.453

CO 7.832 0.28

C4H10 7.22 0.124

C4H2O3 75.64 0.7718

Total 6583.32 229.56

Assuming gases leaving in vent stream saturated with water vapour partial pressure of water at

50°C & 152 kpa = 12.55 kpa

Y = 12.55/152

= 0.08

Total moles of gases in vent = (229.56/0.92)

= 249.52kmole/hr

Moles of water in vent stream = 29.99 * 0.08

= 2.392kmole/hr

=43.056 kg/hr

Water in scrubbed liquid =438.983 -2.392

= 436.51 kmole/hr

= 7859.18 kg/hr


47

Composition of vent stream:


N2 5748.25 205.29

O2 724.46 22.64

CO2 19.93 0.453

CO 7.832 0.28

C4H10 7.22 0.124

C4H2O3 0.76404 0.007796

H2O 43.02 2.392

Total 6867.73 248.75

Composition of bottom:-

component Kg/hr Kmole/hr

Maleic acid 75.64 0.772

Formic acid 0.5655 0.01885

water 7859.18 436.61

Total 7935.26 437.40


48

AROUND DEHYDRATOR

In dehydrator maleic acid is back to maleic anhydride

C4H4O4 C4H2O3 + H2O

In addition to above reaction some maleic acid may irreversibly convert to fumeric acid

according to following reaction.

C4H2O3 + H2O C4H4O4+ C4H4O4

Assuming 0.5% of maleic acid converts irreversibly to fumeric acid & rest 99.5% convert back

to maleic anhydride & 95 % of water is removed by azeotropic distillation dehydrator.

Azeotropic composition

Water = 77.5 % mole

O-xylene = 22.5 % mole

Maleic acid coming from absorber = 75.64 kg/hr

Fumeric acid produced = 75.64 * (0.5/100)

= 0.3782 kg/hr

Maleic acid converted to maleic anhydride = 75.64 – 0.3782

= 75.262 kg/hr

Maleic anhydride produced = 75.262 kg/hr

H2O produced = 75.262 kg/hr

Total water in dehydrator =7859.18 + 75.262

= 7934.4 kg/hr


49

O-xylene:-

= 0.225 * 43.056

= 9.68 kg/hr

As 95% water is removed from the dehydrator so bottom stream contains

Water = 0.95 * 7934.4

= 7537.68 kg/hr

O-xylene = 0.05 * 9.68

= .484 kg/hr

Composition of top stream


water 396.72 22.04


O-xylene .484 0.0387

Fumeric acid 0.3782 0.0126

Formic acid 0.5655 0.0188

Total 476.96 22.87

Bottom component Kg/hr Kmol/hr

O-xylene 9.196 0.088

water 7537.68 418.76


50

AROUND MIXER

In mixer one input stream from crude tank while second input stream from denhydrator they are

mixed together then feed to distillation.

Stream from crude tank + stream from dehydrator = feed to distillation column

For maleic anhydride = 50.936 + 75.262

= 126.2 kg/hr

For water = 396.76 +0.6122

= 397.37 kg/hr

=22.07 kmol/hr

For formic acid = 0.5655 + 0.005713

= 0.5712 kg/hr

Output from mixer:



Water 397.37 22.07

Formic acid 0.57122 0.01904

Fumeric acid 0.3782 0.00326

Total 524.51 23.50


51

AROUND DISTILLATION COLUMN

Assuming 99% of Maleic anhydride is recovered from bottom

And 98% water recovered from top.

98% fumaric acid at top and 2% at bottom of the total amount.

Overall material balance

F= D+W

524.51= D+W

Maleic anhydride balance

126.2= .02 D+.99W

Solving both the equations

D=405.22 kg/hr

W=124.16 kg/hr

So in distillate:

MAN = 0.99*124.16

=123 kg/hr

2.95 ton /day = 3 tonns.

Water = .01*124.16

=1.24 kg/hr

Fumeric acid = 0.3782 *.02

= 0.007564 kg/hr


52

Formic acid = .5*0.57 =0.28kg/hr

In the top :

Water = .98*409.15

= 400.96 kg/hr

MAN= .02 * 409.15

=8.183 kg/hr

Fumeric acid= .98 * 0.3782

=.3706 kg/hr

Formic acid = .5*0.57

=0.28kg/hr

Composition of bottom stream:


Maleic anhydride 123 1.255

Fumeric acid 0.00657 0.0000581(negligible)

Formic acid 0.280 0.009348(negligible)

water 1.24 .0689

Total 122.06 1.3364


53

Composition of top stream


water 400.96 22.27


Fumeric acid 0.3706 .003279(negligible)

total 409.8 22.36

Material balance summary

components 1 Air inlet

2 Butane inlet

3 Reator outlet

4 Gas cooler

5 Seperator top

6 Separator bottom

7 (top) abs

8 (bottom abs)

Maleic anhy 0 0 1.3 1.3 .7796 .519 .0077 0.772

Nitrogen 205.3 0 205.3 205.3 205.3 0 205.25 0

Oxygen 53.88 0 22.64 22.64 22.64 0 22.64 0

butane 0 1.788 .3027 .3027 0.3027 0 0.124 0

Co2 0 0 .59 .59 .59 0 0.453 0

CO 0 0 .525 .525 .525 0 0.28 0

water 7.7 0 14.08 14.08 13.79 .2816 19.96 433.67 Formic acid 0 0 0.01904 0.01904 .0188 .8008 0 0.01885 Acrylic acid 0 0 0.1601 0.1601 .1601 0 0 0

Fumeric acid

0 0 0 0 0 0 0 00

O- Xylene 0 0 0 0 0 0 0 0


54

components 9 dehy

10 Dehy op

11 mixer

12 Dc top

13 Dc bot

Maleic anhy 0 0.768 1.29 .0835 1.255

Nitrogen 0 0 0 0 0

Oxygen 0 0 0 0 0

butane 0 0 0 0 0

Co2 0 0 0 0 0

CO 0 0 0 0 0

water 0 21.89 22.17 22.27 .0689

Formic acid 0 0.0188 0.019 0.0092 .0093

Acrylic acid 0 0 0 0 0

Fumeric acid 0 0.0126 .0032 .0032 .00005

O- Xylene .774 0.0387 0 0 0


55

Chapter 7

ENERGY BALANCE


56

AROUND AIR COMPRESSOR:-

Inlet condition Temperature = 303°K Pressure = 101 Kpa

Outlet condition pressure = 200 Kpa

Inlet flow rate = 7695.54 kg/hr

= 0.0737 kmole/s

Inlet volumetric flow rate

V = 𝑛𝑅𝑇𝑃

V = 0.0737∗8.314∗303101

V= 1.83 m3/s

From fig 3.6 of colusonvol 6 for this flow rate centrifugal compressor would be used with

efficiency εp = 70%

Outlet temp:-

T2 = T1(𝑃2𝑃1)m

Where

m = (𝛾−1𝛾𝜀𝑝

) for air γ = 1.4

substituting the value of γ&εPwe get

m = 0.408

T2 = 303(200101)0.408

T2 = 400°K

T2 = 127°C


57

To calculate work per kmole

W = ZTR ( 𝑛𝑛−1

) [( 𝑝2𝑝1)𝑛−1𝑛

- 1]

Where

n = ( 11−𝑚

) = 1.68

substituting all the value & (z =1) in above equation

w = 1982.57 Kj/kmole

Power required

= 𝑊𝜀𝑝

= 1982.57∗10^30.7

= 2.83 MW

AROUND AIR PREHEATER:-

Inlet condition : Temperature = 127 °C pressure = 200 Kpa

Outlet condition : Temperature = 260°C pressure = 200kpa

Moisture in air = 7.683 kmole

Heat taken by air

Q = (mCpdry air) * (Tout – Tin)

= [(265.36*0.2414)]*(260-127)

= 8519.70 Kcal/hr

Amount of dowtherm required to raise the temperature


58

Q = mλ

8519.70 = m*71.04

m = 119.92 kgmole/hr

AROUND BUTANE PREHEATER:-

Inlet condition: Temperature = 30°C Pressure = 101 Kpa

Outlet condition : Temperature = 100°C Pressure = 101 Kpa

Heat taken by butane preheater

Q = mcpΔT

= 103.75* 0.544*(100-30)

= 3950.8Kcal/hr

Amount of steam required to raise the temperature

Q = mλ

3950.8 = m* 541.68

m = 7.29kgmole/hr

Data for feed mixture at 180°C

components Kg/hr Kmole/hr Mole fraction ΔHf

(kcal/Kmol)

Cp

(kcal/kgmole°C)

Butane 103.75 1.78 0.00686 525.76 0.43

Air 7472.71 257.66 0.9931 0.2447

7576.46 259.44


59

Cpavg of mixture = ∑xicpi

= (0.0065*0.43 + 0.9479*0.2447 +0.0455*1.004)

Cpavg of mixture = 0.245 kcal/kmole°C

COMPONENT IN REACTOR:-

compnents Kg/hr Kmole/hr Mole fraction ΔHf(kcal/kmol) Cp (kcal/kgmole°C)

MAN 127.34 1.3 0.00531 -96000 0.301

CO 14.076 0.5027 0.00205 -26420 0.25

CO2 26.98 0.613 0.002506 -94050 0.238

N2 5748.25 205.29 0.839 0.249

O2 724.46 22.63 0.0925 0.223

H2O 253.44 14.08 0.0575 -57800 0.438

CH2O 0.5713 0.01904 0.0000778 -41769 0.331

C3H4O2 11.53 0.1601 0.000654 -17881 0.421

C4H10 17.56 0.3027 1.23 * 10-3 0.43

Total 6924.23 244.59

To calculate the enthalpy of product & reactant

ΔH = ΔHf° + ∫ 𝐶𝑝𝑑𝑡𝑇2

𝑇1

ΔHbutane= 525.76 + 0.43(180-30) * 58

= 4266.76 kcal/kmole


60

ΔHair= 0.2447 * (180-30) * 29


ΔHMAN = -96000 + 0.331*(350-30) * 98

= -85619.84 kcal/kmole

ΔHCo= -26420 + 0.25 *(350-30)* 28

= -24180 kcal/kmole

ΔHN2 = 0.249 * (350-30) * 28


ΔHO2 = 0.223*(350-30) * 32


ΔHH20 = -57800+ 0.438*(350-30)* 18


ΔHformicacid = -41769 + 0.331 *(350-30)*30


ΔHacyrilicacid= - 17881 + 0.421 *(350-30) * 72

= - 8181.16 kcal/kmole

Heat of reaction = (ΔHproduct-ΔHreactant)

= (-207334.96) – (5331.2)


61

ΔHR = -212666.16 kcal/kmol

Heat given by reactor = heat taken by LP tseam

ΔHi + ΔHR – Ho = HSo – HSi

ΔHi= heat content of feed inlet stream

Hi = mcpΔT + mλbutane

= 271.81 * 0.282*(180-30)+1.78 *(628.84)

Hi = 12616.89 kcal/hr

Ho = heat capacity of product gas

Ho = mcpΔT + mλ

= 244.59 * 0.259*(350-30) + (1.3*7112) + (14.08* 4512)+(0.0190*2977)+ (0.1601*2653.9)

= 93527.63 kal/hr

ΔHR = -212666.16 *(1.78)

= -378545.76kal/hr

Heat content of steam= mcpΔT

HSo + HSi = m*(0.0566)*(140-120)

(12616.89 +378545.76 – 93527.63) = m*(0.0566)*(140-120)

m = 262.92 * 103kgmole/hr


62

AROUND GAS COOLER:-

Stream from reactor is cooled from 350°C to 120°c before it goes to separator.

compnents Kg/hr Kmole/hr Mole fraction Cp

(kcal/kgmole°C)

MAN 127.34 1.3 0.00531 0.2184

CO 14.076 0.5027 0.00205 0.249

CO2 26.98 0.613 0.002506 0.231

N2 5748.25 205.29 0.839 0.241

O2 724.46 22.63 0.0925 0.2215

H2O 253.44 14.08 0.0575 0.426

CH2O 0.5713 0.01904 0.0000778 0.261

C3H4O2 11.53 0.1601 0.000654 0.32

C4H10 17.56 0.3027 1.23 * 10-3 0.41

Total 6924.23 244.59

Cpavg at 120°C = ∑xiCPi

= 0.25

Heat given by product gases = heat taken by dowtherm

mcpΔT = mcpΔT

(244.59*0.25*(350-120)) = m(0.00453*(120-30))


63

m = 34.49 * 103kgmole/hr

AROUND SCRUBBER:-

Operating temperature of scrubber is 50°C

(heat in feed entering) + (heat absorbed by cooling water) + (heat of reaction) = (heat at bottom)

+ (heat carried by vent stream)

C4H2O3 + H2O C4H4O4 …………………………. ΔH = -290.56 kcal

Heat in feed stream

Component Kg/hr Kmole/hr Mol fraction Cp kcal/kgmole°C

N2 5748.25 205.3 0.8410 0.241

O2 724.46 22.64 0.09274 0.2215

H2O 248.37 13.79 0.0565 0.456

CO2 26.398 0.59 0.002416 0.231

C4H2O3 76.404 0.7796 0.003193 0.2184

CO 14.076 0.525 0.00215 0.249

C4H10 17.56 0.3027 0.001313 0.41

CH2O 0.5655 0.0188 7.7 * 10-5 0.261

C3H4O2 11.53 0.1601 6.5 *10-4 0.32

Total 6867.61 244.106


64

Cpavg = ∑XiCpi

= 0.25

Q = mcpΔT

= 244.106 *0.25*(80 – 50)

= 1830.75 kcal/hr

Heat at bottom stream

component Kg/hr Kmole/hr Mol

fraction

Cp kcal/kgmole

°C

Maleic acid 75.64 0.772 1.776*10-3 0.321

Formic acid 0.5655 0.01885 4.34*10-5 0.21

water 7806.06 433.67 0.998 1

Total 7882.26 434.46

Cpavg = ∑XiCpi

= 0.99

Q = mcpΔT

= 434.46*0.99*(80-50)

Q = 11730.42 kcal/hr


65

Heat of vent stream

components Kg/hr Kmole/hr Mol fraction Cp

kcal/kgmole°C

N2 5748.25 205.29 0.825 0.23

O2 724.46 22.64 0.0910 0.225

CO2 19.93 0.453 1.82*10-3 0.21

CO 7.832 0.28 1.12*10-3 0.22

C4H10 7.22 0.124 4.98*10-4 0.39

C4H2O3 0.76404 0.007796 3.13*10-5 0.3

C3H4O2 11.52 0.1601 0.08024

Total 6519.9 228.95

Cpavg = ∑ XICpi

= 0.212

Q = mcpΔT

Q = 228.95 *0.212*(80-50)

Q = 1456.122 kcal/hr

(1830.75+ (m * 0.97 * (80-30) + (-290.56)) =(11730.42+ 1456.122)

Amount of water required

m = 240.13kgmole/hr


66

AROUND DEHYDRATOR:-

top plate temperature = 55°C

Bottom temperature = 120°C

C4H4O4C4H2O + H2O ΔH = -320 kcal/hr

Feed to dehydrator


fraction

Cp kcal/kgmole

°C

Maleic acid 75.64 0.772 1.77*10-3 0.31

Formic acid 0.5655 0.01885 4.34*10-5 0.20

water 7806.06 433.67 0.998 1.006

Total 7882.26 434.46

Cpavg =1

Q= mcpΔT

= 434.46*(1*(55-50))

= 2172.3 kcal/hr

Feed to condenser

Overhead product is condensed from 55°C to 45°C at 15.2 Kpa

Boiling point of water at 15.2 Kpa = 53.6 °C

Boiling point of O-xylene at 15.2 Kpa = 85.05°C


67

components Kg/hr Kmole/hr Molfrac Cp kcal/kg°C

water 7881.29 437.84 0.99 0.97

O-xylene 80.83 0.76 1.72*10-3 0.44

Total 7962.12 438.6

Cpavg = 0.98

Q = mcpΔT

438.6*0.98*(55-30)

= 10745.7 kcal/hr

Feed leaving condenser

components Kg/hr Kmole/hr Molfrac Cp

kcal/kgmole°C

water 7881.29 437.84 0.99 0.97

O-xylene 80.83 0.76 1.72*10-3 0.44

Total 7962.12 438.6

Cpavg = 0.98

Q = mcpΔT

438.6*0.98*(45-30)

= 6477.42 kcal/hr


68

(heat duty of over head condenser) = (heat duty in) – (heat duty out)

= (10745.7) - (6477.42)

= 4268.28 kcal/hr

Bottom of the dehydrator composition

component Kg/hr Kmole/hr Molfrac Cpkal/kgmole°C

water 394.07 21.89 0.96 0.97

Maleic anhydride 75.262 0.768 33.80* 10-3 0.366

O-xylene 4.0415 0.0387 1.70* 10-3 0.45

Fumeric acid 0.3782 0.0126 5.54* 10-4 0.52

Formic acid 0.5655 0.0188 8.27* 10-4 1.3

Total 474.31 22.72

Cpavg = 0.94

Q = mcpΔT + λ

22.72*0.94*(120-50) + 10763.96

= 12258.9 kcal/hr

Total heat load in reboiler

= (heat carried by bottom stream) +( heat fed to condenser) +(heat of reaction)-

(heat carried feed stream)

= (12258.9) + (10745.7) + (-320) – (2172.3)


69

= 20512.3kcal/hr

AROUND DISTILLATION COLUMN:-

Top plate temperature = 110°C

Reboiler temperature = 185°C

Feed stream temperature = 160°C


fraction

Maleic anhydride 126.2 1.29 0.0548

Water 399.13 22.17 0.943

Formic acid 0.57122 0.01904 8.14*10-4

O-xylene 4.0415 0.03806 1.62 * 10-3

Fumeric acid 0.3782 0.00326 1.38 *10-4

Total 530.32 23.50

Cpavg = 0.945

component Feed

(kmole/h

r)

Feed

(mol

fraction)

Distillate

(kmole/hr)

Distillate

(mol

fraction)

Residue

Kmole/hr

Residue

Mol

fraction

Maleic anhydride 1.29 0.0548 0.0128 5.76 *10-4 1.29 0.99

Water 22.17 0.943 22.17 0.997

Formic acid 0.01904 8.14*10-4 0.00326 2.48 *10-4

O-xylene 0.03806 1.62 * 10-3 0.0387 1.74 *10-3


70

Fumeric acid 0.00326 1.38 *10-4 0.0190 0.014

Total 23.50 22.22 1.31

Reflux ratio =𝐿𝐷

= 1.9

L = 1.9D

L= 1.9 * 22.22

= 42.21kmole/hr

V = L+ D

= 42.21+ 22.22

V= 64.43kmole/hr

components

L

(kmole/hr)

V

(kmole/hr)

Mole fraction Λ

Kcal/kmole

MAN 0.03056 0.0466 0.001373 14417.59

water 22.17 33.84 0.99 9750.24

Formic acid 0.01904 0.029 0.000854 3614.4

0-xylene 0.03806 0.0058 0.000171 8841.37

Fumeric acid 0.00326 0.004975 0.000146 2476.35

Total 33.92


71

λavg = ∑ Xiλi


Condenser load

Qc = mλavg

= 33.92 * 9677.49

= 328260.46 kcal/hr

Condenser load = heat taken by water

Qc = mCpΔT

328260.46 = m*1*(100-30)

m = 4689.43 kg/hr

To calculate reboiler load

QB + Hf = QC + HD +HW

Heat content of feed at 160°C =mCpΔT

Hf=23.50*0.935*(160-30)

= 2993.9 kcal/hr

Heat content of distillate at 110°C = mCPΔT

HD = 22.22*0.96*(110-30)

= 1706.49 kcal/hr

Heat content of Residue at 180°C = mCPΔT

HW = 1.29 * 0.37*(180-30)


72

= 71.59 kcal/hr

QB = 4689.43 + 71.59 + 1706.49 – 2993.9

= 3473.61 kcal/hr

Reboiler load = heat given by HP steam

3473.61 = m *CpΔT

= m * 0.99 *(200-180)

m = 175.43kgmole/hr


73

Chapter 8

DESIGN OF DISTILLATION COLUMN


74

In industry it is common practice to separate a liquid mixture by distillating the component,

which have lower boiling points when they are in pure condition from those having higher

boiling points. This process is accomplished by partial vaporization and subsequent condasation.

Here in our project “ production of maleic anhydride from n-butane” maleic anhydride is

separated from water.

The choice between plate and packed column

Vapour liquid mass transfer operation may be carried either in plate column or packed

column. These two types of operations are quite different. A selection scheme

considering the factors under four headings.

i. Factors that depend on the system i.e, Scale , foaming, fouling factors, corrosive

systems, heat evolution, pressure drop, liquid holdup.

ii. Factors that depend on the fluid flow moment.

iii. Factor that depends upon the physical characteristics of the column and its

internals i.e, maintenance, weight, side stream, size and cost.

iv. Factors that depend upon mode of operation i.e, batch distillation, continous

distillation, turndown, intermittent distillation.

The relative merits of plate over packed column are as follows:

I. Plate column are designed to handle wide range pf liquid flow rates

without flooding.

II. If a system contains solid contents , it will be handled in plate column,

because solid will accumulate in the voids and coating the packing

materials and making it ineffective.

III. Dispesion difficulties are handled in plate column when flow rate of liquid

are low as compared to gases.


75

IV. For large column heights, weight of packed column is more than plate

column.

V. If periodic cleaning is required, main holes will be provided for cleaning.

In packed columns packing must be removed before cleaning.

VI. For non- foaming systems the plate column are preffered.

VII. Design information for plate column are more readily available.

VIII. Inter stage cooling can be provided to remove heat of reaction.

IX. When temperature change is involved, packed may be damaged.

DISTILLATION COLUMN DESIGN

a) Feed composition & flow rate:

component Kg/hr Kmole/hr Mole fraction

Maleic anhydride 126.2 1.29 0.237

Water 399.13 22.17 0.7526

Formic acid 0.57122 0.01904 .001077

Fumeric acid 0.3782 0.00326 .0007131

Total 530.32 23.50 1


76

b) Top product composition and flow rate:

components Kg/hr Kmole/hr Mole fraction

water 400.96 22.2 0.978

Maleic anhydride 8.183 0.0835 .0199

Formic acid .28 .009334(negligible) .0000683

Fumeric acid 0.3706 .003279(negligible) .0000904

Total 409.8 22.36 1

c) bottom product compositions and flow rates:

ASSUMPTION:

Binary distillation (water and maleic anhydride)

Ideal gas behaviour of vapours.

1. BOTTOM TEMPERATURE (𝑻𝒃):

Bubble point calculations:-

𝑃𝑡 = 1.2 atm

components Kg/hr Kmole/hr Mole fraction

Maleic anhydride 123 1.255 .986

Fumeric acid 0.00657 0.0000581(negligible) .0000526

Formic acid 0.280 0.009348(negligible) .002245

Water 1.24 .06889 .0099

Total 124.7 1.33 1


77

𝑇=185°C

Components Xb=Xi V.P(psia) Ki=v.p/Pt Yi=Ki.Xi

Maleic anhydride .986 11.76 0.8 .788

Water .0099 1.8 12.24 0.1211

total 1.00 .98

2. TOP TEMPERATURE (𝑻𝒅):

Dew point calculations:

𝑃𝑡=1.2tm

Td=110°C (assume)

3. TEMPERATURE OF FEED:

𝑇𝑓= 160°C

4. FEED CONDITIONS

Dew point calculations:

Components Yi=Xf V.P(psia) Ki=v.p/Pt Xi=Yi/Ki

Maleic anhydride .0199 0.7 0.048 0.4145

Water .978 23 1.56 0.627

Total 1.00 1.04


78

T=160.5°C

Components 𝐘𝐢=𝐗𝐟 V.P(psia) 𝐊𝐢=V.P/𝐏𝐭 𝐗𝐢=Yi/Ki

water .7526 100 6.8 .1106

Maleic anhydride 0.237 5.17 .325 .7292

total 0.99 1

Since the dew point of feed is same as feed temperature so feed is at its dew point.

5. CALCULATION OF RELATIVE VOLATILITY (α):-

𝑇𝑓=feed temperature (C)= 160°C

Light key component (LK)=water

Heavy key component (HK) = maleic anhydride

6. MINIMUM NUMBER OF PLATES(NM):

Fenske equation:

Nm=ln��xd 1−xd� � �

1−xbxb

� �

ln(αAB)av

component Top

bottom Average

α

Ki 𝜶𝒅𝒊=𝑲𝒊

𝑲𝑯𝑲� 𝑲𝒊 𝜶𝒃𝒊=Ki/Khk

Maleic anhydride 0.048 1 0.8 1 1

Water 1.56 32.5 12.24 15.3 23.9


79

xd=mole fraction of more volatile component in the overhead distillate

xb=mole fraction of more volatile component in the bottoms.

(𝛼𝐴𝐵)𝑎𝑣 = α = 23.9

𝑁𝑚= 2.64 = 3

7. CALCULATION OF 𝑹𝑴(MINIMUM REFLUX RATIO):

UNDER WOOD METHOD;

𝛼𝐴.𝑥𝑓𝐴𝛼𝐴−𝜃

+ 𝛼𝐵.𝑋𝑓𝐵𝛼𝐵−𝜃

= 1-q

As feed is at its new dew point so q = 0.

And we get θ = 12.3.

Using eqn of min. Reflux ratio,

𝛼𝐴.𝑥𝑓𝐴𝛼𝐴−𝜃

+ 𝛼𝐵.𝑋𝑓𝐵𝛼𝐵−𝜃

= 𝑅𝑚+ 1

A= water, LK

B= maleic anhydride, HK

𝑋𝑓𝐴= mole fraction of component corresponding to light key in feed.

𝑋𝑓𝑏= mole fraction of component corresponding to heavy key in feed.

𝑅𝑚 = 1.52

8. REFLUX RATIO (R)

R= 1.25 (𝑅𝑚)

http://en.wikipedia.org/wiki/Mole_fraction

http://en.wikipedia.org/wiki/Volatility_(chemistry)


80

= 1.9

9. ACTUAL NUMBER OF THEORITICAL STAGES:

From “kirk bride” relation

𝑁−𝑁𝑚𝑁+1 = 0.75 [ 1-�𝑅−𝑅𝑚𝑅+1 �

0.566]

N = 7.19= 7

10. COLUMN EFFICIENCY:

E = 0.17- 0.616* log10 ∑ 𝑥𝑓 . µ1µ𝑤

Where

µ1=viscosity of liquid at mean tower temperature

µ𝑤= viscosity of water at 293K

𝑋𝑓= mol fraction of components in feed.

Mean tower temperature = 147.5C = 420.5K

µ1= 0.174cp

µ𝑤= .83cp

𝑋𝑓=0..7526

For maleic anhydride

µ1=0.485cp

µ𝑤=0.83cp


81

𝑋𝑓=0.237 so,

E= 0.496

11. ACTUAL NUMBER OF PLATES:

Taking reboiler as a stage,

𝑁𝑎= 𝑁−1𝐸

Where,

𝑁𝑎=actual no of plates.

N= theoretical plates.

E= efficiency.

𝑁𝑎= 12.47= 13

12. FEED PLATE LOCATION:

log[𝑁𝐷 𝑁𝐵⁄ ]= 0.206 * [𝐵𝐷∗ �𝑋𝐻𝐾

𝑋𝐿𝐾�𝐹∗ �(𝑋𝐿𝐾)𝐵

(𝑋𝐻𝐾)𝐷�2

]

𝑁𝐷= no of stages above the feed plate

𝑁𝐵=no of stages below the feed plate

B= molar flow rates of bottom

D= molar flow rate of distillate

𝑋𝐿𝐾=mole fraction of light key comp


82

𝑋𝐻𝐾= mole fraction of heavy key comp.

Put

B=1.33kmol/hr

D=22.36 kmol/hr

𝑁𝐷/𝑁𝐵= .8106

𝑁𝑎-𝑁𝐵= 0.8106𝑁𝐵

𝑁𝐵=7.7 ,𝑁𝐷=6.2

So feed enters the column at 7th stage

13. COLUMN PRESSURE DROP:

Assume 170 mm water pressure drop per plate.

Total pressure drop = 9.81*10−3.ℎ𝑡 ∗ 𝑁𝑎 ∗ 𝜌𝑙

Where,

ℎ𝑡=total plate pressure drop( mm liquid)

𝜌𝑙= density of liquid at 25C

𝑁𝑎= actual no of plates

By putting values in above eqn

𝑡= 20734.66 pa

Top pressure = 121.6*103pa

Estimated bottom pressure

= 142334.66 pa

= 1.404 atm


83

14. LIQUID VAPOUR FLOW FACTORS:

𝐹𝐿𝑉= �𝜌𝑣𝜌𝑙�

.5∗ �𝐿𝑚

𝑉𝑚�

Where,

𝐿𝑚= liquid flowrate (kg/sec)

𝑉𝑚= vapour flowrate(kg/sec)

𝑅 = 𝐿/𝐷

R = 1.9 ( calculated)

D = 22.36 kmol/hr

L = 1.9* 22.36

L =42.48 kmol/hr

L = 0.21242 kg/sec

FOR TOP:

Balance around condenser

𝑉𝑛=𝐿𝑛+ D

𝑉𝑛 = 42.48 + 22.36

= 64.84kmol/hr

=0.3242 kg/sec

𝑇𝑡𝑜𝑝= 110°C

Avg mol wt = 19.6 kg/kmol

𝜌𝑣=0.75 kg/𝑚3

𝜌𝑙=963.95 kg/𝑚3

So

𝐹𝐿𝑉𝑡𝑜𝑝=0.0176


84

FOR BOTTOM:

Balance around reboiler

𝐿𝑀=𝑉𝑀+B

42.48= 𝑉𝑀+ 1.33

𝑉𝑀=41.15 kmol/hr

= 0.205 kg/sec

𝑇𝑏𝑜𝑡𝑡𝑜𝑚=185°C

Avg mol wt= 96.3

𝜌𝑣=3.7kg/𝑚3

𝜌𝑙=1302.2 kg/𝑚3………………………. ( from table)

Putting values

𝐹𝐿𝑉𝑏𝑜𝑡𝑡𝑜𝑚=0.05522

15. FLOODING VELOCITY:

Uf=K1 ∗ �𝜌𝑳−𝜌𝑽𝜌𝑽

Uf= flooding vapour velocity

Corrected 𝐾1= 𝐾1∗ ∗ � 𝛔0.02�

.2

𝜎 =surface tension

By “sudgenparachor” method

𝜎 =�𝑃𝐶ℎ.�𝜌𝐿−𝜌𝑉�𝑀 �

4*10−12

where

𝜎 = surface tension

𝑃𝐶ℎ=sudgen’s sparachors constant

M = mol wt.

AT TOP:-

𝐾1∗=0.095


85

𝑃𝐶ℎ=54.2

𝜎𝑡𝑜𝑝=50 mJ/𝑚2

K = 0.114

Uf= 4.08 m/s

Bottom 𝑈�𝑣 =0.85*Uf =2.2m/s

AT BOTTOM:

From fig 3.1,

𝐾1∗= 0.090

𝑃𝐶ℎ=216.6

𝜎𝑏𝑜𝑡𝑡𝑜𝑚 =21.7*10−3 N/m

𝐾1 = 0.0912

Uf =2.58m/s

Designing at 85% flooding at maximum flow rate

Top 𝑈�𝑣 = 0.85*Uf = 3.47 m/s

16. MAXIMUM VOLUMETRIC FLOW RATE:

top:-

𝑉𝑛 = 64.84 kmol/hr


86

=.018 kmol/sec

Max volumetric flow rate =𝑉𝑛𝑋𝑀𝜌𝑉

= 0.47 𝑚3/s

bottom:-

V𝒎 = 41.15kmol/hr = .0114kmol/sec

Max volumetric flow rate = 𝑉𝑛𝑋𝑀𝜌𝑉

= 0.295𝑚3/sec

17. NET AREA REQUIRED:

A = 𝑚𝑎𝑥𝑖𝑚𝑢𝑚𝑣𝑜𝑙.𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒𝑈�𝑣

𝐴𝑡𝑜𝑝 =0.135𝑚2

𝐴𝑏𝑜𝑡𝑡𝑜𝑚 =0.134𝑚2

18. COLUMN CROSS – SECTIONAL AREA:-

Taking down comer area as 12% of total

𝐴𝐶𝑡𝑜𝑝=𝐴𝑡𝑜𝑝0.88

= 0.154𝑚2

𝐴𝐶𝑏𝑜𝑡𝑡𝑜𝑚=𝐴𝑏𝑜𝑡𝑡𝑜𝑚0.88

=0.152𝑚2


87

19. COLUMN DIAMETER:-

D= �4𝑋𝐴𝑐𝛱

𝐷𝑡𝑜𝑝 = 0.442m

𝐷𝑏𝑜𝑡𝑡𝑜𝑚 =0.433 m

20. LIQUID FLOW PATTERNS:

MAXIMUM VOL. FLOW RATE = 𝐿𝑛 x M3600𝑥𝜌𝑙

𝜌𝑙=density of liquid( kg/𝑚3)

𝐿𝑛= liq flow rate (kmol/hr)

Put

𝐿𝑛=64.84 kmol/hr

𝜌𝑙=963.95 kg/𝑚3

M = 19.6

So max vol flow rate= 1.79x10−3𝑚3/sec


88

21. PROVISIONAL PLATE DESIGNING:-

Sieve plate selected

Column dia = 𝐷𝑐 = 0.442m

Column area=𝐴𝑐=0.154𝑚2

Downcomer area= 𝐴𝑑= 0.12𝐴𝑐= 0.01848𝑚2 (12% of 𝐴𝑐)

Net area = 𝐴𝑛=𝐴𝑐-𝐴𝑑= 0.13552𝑚2

Active area =𝐴𝑎=𝐴𝑐-2𝐴𝑑=0.11704𝑚2

𝐴ℎ=hole area(total)=𝐴𝑎x 0.1= 0.011704𝑚2 (10% of 𝐴𝑎)

From fig 3.3

𝑙𝑤𝐷𝑐

=0.76

𝑙𝑤=weir length

=0..335m

Take weir height = 50 mm

Hold diameter =𝑑ℎ = 5mm

Plate thickness = 5 mm


89

22. CHECK WEEPING:

Max liquid flow rate = 𝐿𝑚𝑋𝑀3600

Where

𝐿𝑚=liquid flow rate below feed plate (kmol/hr)

Put

𝐿𝑚=64.84 kmol/hr

M wt = 96.3

Max liq flow rate= 1.734 kg/sec

Max liq flow rate at 70% turndown = 0.7*1.734=1.214 kg/sec

Weir liquid crest:

ℎ𝑜𝑤=750 x� Lwlwx𝜌l

�𝟐𝟑�

Where

ℎ𝑜𝑤=weir crest (mm liquid)

lw=weir length

Lw= Liquid flow rate,kg/sec

𝜌l= liquid density at bottom, kg/𝑚3


90

For minimum

Put

lw=0.335m

Lw=1.214, kg/sec

𝜌l= 1302.2 kg/𝑚3

So,

ℎ𝑜𝑤= 14.83(mm liquid)

For maximum

Put

lw=0.335m

Lw=1.734 kg/sec

𝜌l=1302.2 kg/𝑚3

So,

ℎ𝑜𝑤= 18.82(mm liquid)

At minimum rate,

ℎ𝑜𝑤+ℎ𝑤= 65.5 mm liquid

ℎ𝑜𝑤=14.83 mm liquid

ℎ𝑤=50.67 mm liquid


91

23. WEEP POINT:-

a. Minimum vapour velocity through holes:

Uh�=[ 𝑘2−0.90 (25.4 −𝑑ℎ)]

𝜌𝑣1 2�

𝜌𝑣= vap density at base

𝑑ℎ=hole dia, mm

𝑘2=constant

Put

𝜌𝑣=3.7 kg/𝑚3

𝑑ℎ=5mm

𝑘2=30.3

So,

Uh�= 6.2m/s


92

b. Actual minimum vapour flow velocity:

U𝑎=𝑚𝑖𝑛𝑣𝑎𝑝𝑜𝑢𝑟𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒𝐴ℎ

= ( 0.7x0.295) / 0.01170 = 17.7 m/sec

Since the total minimum vapour rate is above weep point, no weeping occurs.

24. PLATE PRESSURE DROP:-

I. Maximum vapour velocity through holes:-

𝑈ℎ = max𝑣𝑜𝑙.𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒 (𝑡𝑜𝑝)𝐴ℎ

= 0.47/0.011704 = 40.15m/sec

II. Pressure drop through dry plate:-

ℎ𝑑 = 51 �𝑈ℎ𝑐0�2 𝜌𝑙𝜌𝑣

Where,

𝑐0= constant

At plate thickness / hole dia = 5mm/ 5mm=1

𝐴ℎ𝐴𝑎

=0.1 &𝑐0 = 0.87

Put

𝜌𝑣=0.75 kg/𝑚3

𝜌𝑙=963.95 kg/𝑚3


93

ℎ𝑑=89 mm liq

III. Residual head:

ℎ𝑟= 12.5 𝑥103

𝜌𝑙

= 12.96 mm liquid

IV. Total pressure drop:

ℎ𝑡=(ℎ𝑜𝑤+ℎ𝑤) +ℎ𝑟+ℎ𝑑

Where

ℎ𝑑= pressure drop through dry plate

ℎ𝑤= weir height

ℎ𝑜𝑤= weir liquid crest(max)

ℎ𝑟= residual head

Putting values

ℎ𝑡= 171.6 mm liq

𝑡ℎ𝑖𝑠 𝑖𝑠 𝑐𝑙𝑜𝑠𝑒 𝑡𝑜 𝑎𝑠𝑠𝑢𝑚𝑒𝑑 𝑣𝑎𝑙𝑢𝑒 𝑜𝑓𝑝𝑟𝑒𝑠𝑠𝑢𝑟𝑒 𝑑𝑟𝑜𝑝. 𝑠𝑜 𝑎𝑐𝑐𝑒𝑝𝑡𝑒𝑑.

25. DOWN COMER BACK UP:

a) Down comer pressure loss:-

Take

ℎ𝑎𝑝=ℎ𝑤- 10

ℎ𝑤= weir height

ℎ𝑎𝑝=40mm

b) Area under apron:

𝐴𝑎𝑝=ℎ𝑎𝑝𝐿𝑤


94

ℎ𝑎𝑝= height of bottom edge of apron above plate

𝐿𝑤=weir length= .335

𝐴𝑎𝑝=.0134𝑚2

c) Head loss in downcomer:-

ℎ𝑑𝑐= 166 � 𝐿𝑤𝑑𝜌𝑙𝐴𝑚

�2

ℎ𝑑𝑐= head loss in down comer (mm)

𝐿𝑤𝑑= liquid flowrate in downcomer

𝐴𝑚= area for clearance

Put

𝐿𝑤𝑑=1.734 kg/sec

𝜌𝑙=963.95 kg/m3

Am = 0.01848𝑚2

So

ℎ𝑑𝑐=.947 mm

d) Back up in downcomer:-

ℎ𝑏𝑐= ℎ𝑑𝑐+ (ℎ𝑤 + ℎ𝑜𝑤 𝑚𝑎𝑥) +ℎ𝑡

Put

ℎ𝑤=50 mm

ℎ𝑑𝑐=.947 mm


95

ℎ𝑜𝑤 𝑚𝑎𝑥=18.82 mm

ℎ𝑡= 190.6 mm liq. . . . . . . . . . . . . . . . . . (already assumed )

So

ℎ𝑏𝑐= 260.36mm = .2603 m

.260< ½ (plate spacing + weir height)

0.260< 0.275

So our plate spacing 0.5 m is acceptable.

26. DOWNCOMER RESIDENCE TIME:

𝑡𝑟=�𝐴𝑑ℎ𝑏𝑐𝜌𝑙𝐿𝑤𝑑

�

Where

𝐿𝑤𝑑=liquid flow rate in downcomer

ℎ𝑏𝑐=dead liquid backup

𝑡𝑟=downcomer residence time

ℎ𝑏𝑐=0.2603 m

𝐴𝑑=0.01848𝑚2

𝐿𝑤𝑑=1.734 kg/s

So

𝑡𝑟= 3.61 sec > 3 (satisfactory)


96

27. CHECK ENTRAINMENT:-

% flooding = 𝑈𝑛𝑈𝑓

Where

𝑈𝑛= actual velocity based upon net area

𝑈𝑓= flooding velocity

𝑈𝑛= max 𝑣𝑜𝑙.𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒𝑛𝑒𝑡𝑎𝑟𝑒𝑎𝑟𝑒𝑞. (𝐴𝑛)�

Putting the values

max 𝑣𝑜𝑙.𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒 = 0.47

𝐴𝑛= 0.13552𝑚2

𝑈𝑛=3.468 m/s

Since

𝑈𝑓=4.08 m/s

% flooding = 77%

28. NUMBER OF HOLES:

Dia of holes (D) = 50mm =.05m

Area of single hole (𝐴1) =𝛱 4 ∗� 𝐷2 = 1.96*10−5 m2

Total no. of holes = 𝐴ℎ/𝐴1= 597.14


97

29. HEIGHT OF DISTILLATION COLUMN:

No of plates =15

Tray spacing = 0.5 m

Distance between 15 plates = 15 * .5 = 7.5m

Take

Top clearance = 0.5m

Bottom clearance = .5 m

Plate thickness = 5mm / plate = 5*10−3 m/plate

Total thickness of plates = 5 * 10−3 *15 = .075 m

= 75 mm

Total column height = (7.5 +.5+.5+.075) m = 8.6 m

30. MECHANICAL DESIGN:-

Shell material = carbon steel

Sieve plate material = stainless steel 316

Operating pressure = 1.2 atm

Taking design pressure 40% more than operating pressure

Design pressure = 1.68 atm

= 0.168 MPa

Shell diameter = 0.86m

Shell height = 8.6 m

Shell thickness = 𝑡𝑠 =�𝑃

2𝑓𝑗−𝑃�𝐷𝑖 +C

P = design pressure = 0.168 MPa

j = joint efficiency = 0.85


98

C = corrosion allowance for carbon steel = 2mm

f = allowable stress = 96.26 MPa

D = internal diameter

𝑡𝑠= 0.046 m = 46 m


99

Chapter 9

MATERIAL OF CONSTRUCTION


100

Any engineering design,particularly for the chemical processes plant,is only useful when it is

translated into reality by using available material of construction combined with appropriate

techniques of fabrication which play a vital role in success or failure of a new chemical plant.

The task of an engineer is to sort out the available choices and to arrive at the most cost effective

solution to the problem of corrosion.

Traditionally the one employed set of conditions for plant equipments. Plant equipmentsis

protected by coating the equipment with paint.

Wet ,damped and high humidity conditions all contribute to corrosion & premature equipment

failure if not treated properly. These problems are an uphill task to be considered by an engineer.

A engineer must be familiar with the material of construction for all equipments and must be

aware of diverse corrosion control technique involving coating metal, cathodic technique, use of

plastics and even the use of inhibitors.

CORROSION CONTROL METHODS:

The product & its production as well as cleaning purposes and storage involves large amount of

use of water.

They require a large amount of extensive water facilities. Furthermore the product is an acidic

liquid is aggressive to low carbon steel

This is futher complicated that the presence of iron ions in the product drastically affects its shelf

life.

Wet ,damped and high humidity conditions all contribute to corrosion & premature equipment

failure if not treated properly. These problems are an uphill task to be considered by an engineer.


101

A engineer must be familiar with the material of construction for all equipments and must be

aware of diverse corrosion control technique involving coating metal, cathodic technique, use of

plastics and even the use of inhibitors

IMPORTANT MATERIAL OF CONSTRUCTION

Material of construction is mainly divided into two parts metals and non metals. Pure metals and

metallic alloys are included under the first classification.

The list of important material of construction include the following:

• Iron & steel

• Stainless Steel

• Nickel and its alloys

• Copper

• Aluminium

• Lead

• Hastelloy

• Coating

• Floor materials

• Plastics

RECOMMENDED MATERIAL OF CONSTRUCTION:

Maleic anhydride when pure shows corrosive action till its boiling point. Therefore special

material of construction is used in the production & handling of maleic anhydride.

Pure maleic anhydride is probably less corrosive towards stainless steel. Although many

materials have greater corrosion resistance than carbon but cost aspects favors the use of carbon


102

steel. As a result they often use material of construction when it is known as some corrosion will

occur.

Although major equipment in the production of “Industrial Maleic Anhydride” is recommended

to be manufactured by carbon steel some equipment where concentrated H2SO4 and dilute acid

make the use of stainless steel 304 & 316 are mainly used. Otherwise lining of corrosion

resistant material can be used. So recommended material of construction is stainless steel.

MATERIAL OF CONSTRUCTION FOR THE SELECTED PROCESS

The material of construction used in the manufacturing of maleic anhydride from n-butane has to

be selected very carefully taking in consideration the reactive and corrosive nature of maleic

anhydride. The material of construction selected for the main process equipment in the process

holds a great significance in the yield and conversion of the product ie, productivity and also a

main factor in deciding the life of the equipment &plant. Thus the material of construction sums

up for both the technical as well as economic aspect of the production unit.

The material of construction used in construction of the super heater is carbon steel with a

design temperature of 460 f & design pressure of 220 psi. The air compressor is also made from

the same material of carbon steel. The air heater is made up of stainless steel with design

temperature of 850 f & design pressure of 30 psi. It is also provided with a 6" refractory lining.

The reactor is made up of stainless steel with internal rubber lining of 5.75 ".The reactor

provided with the design temperature of 800 f & 50 psi. the steam pot is of stainless steel with

design temperature of 650 f & design pressure 377 psi. The gas cooler used in the equipment is

made up of carbon steel with design temperature of 470-900 f &design pressure of 315-375 psi.

The separator or cyclone in this case is made of stainless steel with design temperature if 30 psi.

The distillation column has to be made from stainless steel with design temperature of400f &

25 psi. It is provided with 20 trays,14 gauge & .250 openings (392 per tray).The last but not the

least material used in piping is made of PVC (poly vinyl chloride) as the liquid flowing through

the streams is very corrosive.

http://psi.it/


103

Chapter 10

COST ESTIMATION


104

DIRECT COST :-

Equipment installation cost = .47 *69628062 = Rs 32725189

Instrumentation & process control cost = 0.12 * 69628062 = Rs8355367

Piping (installed) = 0.66* 69628062 = 45954520

Building (including services) = .18 *69628062 =Rs 12533051

Yard improvement = 0.1 *69628062 =6962806

Service facility (installed) = 0.7 *69628062=48739643

Land = 0.06 * 69628062 =Rs 4177683

SR NO EQUIPMENTS COST ( IN RUPEES)

1. Reactor 29654999.5

2. Absorber 9982000

3. Distillation column 28181116.5

4. Dehydrator 583702

5. Compressor 1 87213.5

6. Filter 21000

7. Gas cooler 695501

8. Separator 120000

9. Preheater1 106729.5

10. Preheater 2 98800

11. Mixer 97000

TOTAL 69628062


105

Total = Rs.159448259

Total direct cost= Rs 229076321

INDIRECT COST:

Engineering cost=0.33* 69628062= Rs. 5015098.5

Construction cost = 0.6* 69628062 = Rs.41786403.5

TOTAL=10419168

TOTAL COST:

Direct cost + indirect cost

=229076321+12419168

= Rs 239495489

Contractor fees

= 0.1 * total cost

=0.1*239495489

=Rs 24102775

Contingency

= 0.2*239495489

=Rs 48203882

Total =Rs 35924323

FIXED CAPITAL INVESTMENT :-


106

= total direct cost+ indirect cost + contractor fees + contingency

=B+C+D

= Rs 311802146

WORKING CAPITAL:-

5% of Fixed capital investment= 0.05 *311802146

= Rs 15590107.3

Total capital investment

= FCI + Working capital

=311802146+15590107.3

=Rs 327392253.3

FIXED COST:-

Cost (in Rs)

Maintaintance cost 5% of FCI 15590107

Operating labour 1000,000

Laboratory cost 20% of OL 200,000

Supervision 20% of OL 200,000

Plant overhead 25% of OL 250,000

Capital charge 1% of FCI 311802

Insurance 3% of FCI 9354064

Local taxes 1% of FCI 3118021

Royalties 2256220

total 32280214


107

VARIABLE COST :

Raw material (rs 29000/MT) = 29,000,000

Electricity (rs 10/MT) = 10,000

Direct production cost = 10% FCI

= Rs 31180214.6

Total = Rs 60190214.6

ANNUAL PRODUCTION COST:

Fixed cost + variable cost

=Rs 92470429.2

Cost / MT = 𝐴𝑃𝐶1000

= 92470429.21000

= 92470.429

Cost / Kg =92.47

Gross profit = 75000/MT

Profit = selling price – cost price

75000* 1000 = selling price – 92470429.2

= 167470429.2

Taxes = 40%of sales price

= .4 * 167470429.2


108

= Rs 66988171.68

(Taxes on rawmaterial,electricity&etc)=40% of cost of rawmaterial,electricity&etc

=0.4*91370429

=Rs 36548171

TOTAL TAXES=103536342.7

Depreciation = 10% of FCI

= .1*311802146

=31180214.6

Net profit = selling price (SP) – taxes

= 166370429 -103096342.6

= Rs 63934086.52

PAY BACK PERIOD:-

= 𝐹𝐶𝐼

𝑝𝑟𝑜𝑓𝑖𝑡+𝑑𝑒𝑝𝑟𝑖𝑐𝑖𝑎𝑡𝑖𝑜𝑛

= 311802146

63934086.52+31180214.6

=3.27 years

RATE OF RETURN:-

= 𝑛𝑒𝑡𝑝𝑟𝑜𝑓𝑖𝑡

𝐹𝐶𝐼 *100 =

63934086.52311802146

*100 =20.50%


109

Chapter 11

PLANT LOCATION & LAYOUT


110

Plant location

Plant location is often the result of compromise among conflictory ,social , economic,

geographical & government considerations.One can get all favourablefactors but ultimately the

aim is lowest cost of production.

The choice of the site for the plant location is very important to be considered as it affects the

economy of the whole process.The proper choice of the site can drastically increase the cost of

production & simultaneously limit the area in which the product can sold profitably.

The proper choice of the site is based on judgement due to experience & thorough knowledge of

co-ordination of the various factors governing it.Some of the important factors are:-

• Availability of raw material

• Transport facilities

• Market for finished product

• Power,labour&water supply at cheap rates.

• Land & taxation liberty,which can encourage the production.

• Banking & other facilities

• Site consideration

• Waste disposal problem

Though n-butane is the main raw material in this factory it is not imported outside but

manufactured at the side plant. n-butane is manufactured economically fromnatural gas.

In India, Ankeleshwar in Gujrat & Chennai are the states which can fulfill the demand of

natural gas. So Gujrat becomes ultimate choice.


111

The site conditions involve not only the selection of site but we have to consider some ther

factors as follows:-

• Atmospheric pressure & temp

• Max & min humidity

• Wind,velocity& snowfall

• Water characteristics.

• Soil conditions


112

Plant layout

It can be called as the internal orgiation of the fixed asset of their company, “The right man in

the right place,with the right machine,in the right motive is the key to successful production.”

The layout has been made taking following point in to consideration:-

• There is a steady flow of work & no cross flow of traffic i.e. absence of back traffic

• Adequate space has been provided for future expansion.

• Disposal aspects


113


114

Chapter 12

MATERIAL SAFETY DATA SHEET


115

1. PRODUCT IDENTIFICATION AND MANUFACTURER/SUPPLIER IDENTIFICATION

Product Name: Maleic Anhydride Synonyms: cis-Butenedioic Anhydride Product Use: Chemical Synthesis, intermediate, CAS NUMBER: 108-31-6 EINECS-NR. 203-571-6 Chemical Formulation: C4H2O3 Product Identification Number: 78800/MANBRI 2. COMPOSITION OF INGREDIENTS

Chemical Name: Cas. no. % by wt Maleic Anhydride 108-31-6 99 % min 3. HAZARDS IDENTIFICATION

DANGER! 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 HMIS Hazard Ratings Health - 3, Flammability - 1, Chemical Reactivity - 1 4. FIRST AID MEASURES Ingestion: Do not induce vomiting. Have a conscious person drink several

glasses of water or Inhalation: Allow the victim to rest in a well ventilated area. Seek immediate

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

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

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

Special Fire-Fighting Procedures:

Wear self-contained breathing apparatus with full face piece operated in the

Hazardous Combustion

Carbon Dioxide, Carbon Monoxide. Unusual Fire and Explosion Hazards:

Unstable, or air-reactive or water-reactive chemical involved (see Section 10). Vapors from melted material can be ignited. Keep melted material away from ignition sources. May form flammable dust-air mixtures when finely

6. ACCIDENTAL RELEASE MEASURES


116

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

Personal precautions cont’d: 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

d 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

Storage: Store away from incompatible materials. Store at temperatures not exceeding 70°C (158°F). Contains moisture sensitive material -- store in a dry place.

8. EXPOSURE CONTROLS/PERSONAL PROTECTION

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

Skin Protection 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. D l i

Respiratory Protection 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

i t ft d t i i th i b t ti f th

Ventilation Adequate to meet occupational exposure limits (see below)


117

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

9. PHYSICAL PROPERTIES Physical Form: Molten liquid Color Water white Odor Strong irritating acrid

Odor Threshold 0.5 ppm

Specific Gravity Molten: 1.3 at 70°C (water = 1.0); Solid: 1.48 at 20°C ( 1 0)

Vapor Pressure 0.2 mm Hg at 25°C

Vapor Density 3.38 (Air = 1.0) Melting Point 52.5°C (126.5°F) Boiling Point 202°C (395°F) Solubility in Water Very soluble

pH 2.42 (0.01 M solution) Solubility in Other Solvents

Chloroform, acetone, ethyl acetate, benzene, h d b di Flash Point 102°C (215°F) (PMCC) Flammable Limits LFL: 1.4% UFL: 7.1%

Autoignition Temperature

477°C (890°F) Thermal Decomposition

>150°C


118

10. STABILITY & 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 concentrations as

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

Hazardous Polymerization Will not self-polymerize but can undergo uncontrolled co-polymerization in the presence of other monomers and catalysts (see Incompatible Materials,

11. TOXICOLOGICAL INFORMATION

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

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

i i i i f l i h d id h b

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 d

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. R t d

12. 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 Bioaccumulative potential This product is not expected to bioaccumulate through food chains in

the Remarks This product will hydrolyze rapidly to the acid. Expected to be slightly

toxic to 13. DISPOSAL CONSIDERATIONS


119

Waste Disposal Methods 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

Remarks Do not allow to enter drains or sewers. Do not allow to drain into surface waters.

14. TRANSPORT INFORMATION

TDG Classification Maleic Anhydride Class 8, UN 2215, PG III, Label: Corrosive DOT Classification Maleic Anhydride Class 8, UN 2215, PG III, Label: Corrosive,

Reportable Quantity: 5000 Lbs (2268 Kg)

15. REGULATORY INFORMATION

WHMIS Classification Class D, Div 1, Subdiv B: Material causing immediate and serious toxic effects (TOXIC) Class D, Div 2, Subdiv A and B: Material causing other toxic effects (VERY TOXIC) Class E: Corrosive Solid

SARA Title III Section 302: This product is not regulated under Section 302 of SARA and 40CFR Part 355 Section 311: Maleic Anhydride, Immediate (Acute) Health Hazard, Delayed (Chronic) Health Hazard Section 313: Maleic Anhydride 100%

CERCLA 102a Maleic Anhydride 100%, RQ 5000 lbs. State Regulations Pennsylvania RTK: Maleic Anhydride (environmental hazard,

generic environmental hazard) Massachusetts RTK: Maleic Anhydride New Jersey RTK: Maleic Anhydride Connecticut RTK: Maleic Anhydride Florida RTK: Maleic Anhydride Illinois RTK: Maleic Anhydride Rhode Island RTK: Maleic Anhydride California prop. 65: no products were found


120

Inventories Canada Inventory (DSL): listed on inventory US Inventory (TSCA): listed on inventory

16. OTHER INFORMATION

Bartek Ingredients Inc. cannot anticipate all conditions under which this information and its product, or the products of other manufacturers in combination with its product, may be used. It is the users' responsibility to ensure safe conditions for handling, storage and disposal of the product, and to assume liability for loss, injury, damage or expense due to improper use. This information is given in good faith, but no warranty, express or implied is made.


121

PIPING & INSTRUMENTATION FLOWSHEET


122


123

CONCLUSION


124

Conclusion:-

The Report generated gives a higher value of the Total Potential Environmental Impact

suggesting that the process has to be modified for environmental purposes. The high value of the

PEI is because of the excess amounts of carbon dioxide released into the atmosphere.

By analyzing all the individual output streams, it can be clearly observed that output stream has

quiet high values of the total PEI. It is because of the release of the purge gas from the gas cooler

directly into the atmosphere.

As a process improvement step, we can use incinerator to convert the Carbon monoxide to

carbon dioxide before it is released into the atmosphere. As an alternative a scrubber can be used

to scrub all the harmful gases and prevent them from entering into the atmosphere.

The other outlet streams mostly contain water other than the product, so they have less

environmental impact.

Changing the solvent in the absorption column from Sucinic anhydride to water can increase the

environmental attractiveness of the process but the required product yield cannot be attained.


125

BIBLIOGRAPHY:

R. Winckler, Annalen der Pharmacie 4, 230 (1832); J. Pelouze, Annalen der Pharmacie 11, 263

(1834).

J. R. Skeen, Chem. Eng. News 26, 3684 (1948).

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