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FORMAT OF MASS BALANCE

Product : Di-ethyl Phthalate (DEP) Kg Per Batch : 5000

Stage: 1 Reaction & Distillation Batches Per Month: 25

Name of The Raw Material

Input qty. in kg / Batch

Recycle qty. in kg / Batch

Liquid Effluent in kg / batch

Solid Waste in kg / batch

Emissions in kg / batch

Output in kg / batch

PATHALIC

ANHYDRIDE 3500 - - - - -

ETHYL ALCOHOL

2600 - - - -

CATALYST 150 300 - - - -

CRUDE

D E P

150

Total 6250 300 150 - - 5800

Stage: 2 Neutralisation, Washing & Drying.

Name of The Raw Material

Input qty. in kg / Batch

Recycle qty. in kg / Batch

Liquid Effluent in kg / batch

Solid Waste in kg / batch

Emissions in kg / batch

Output in kg / batch

CRUDE D E P 5800 - - - -

WASH WATER 1500 - - - -

CAUSTIC SODA 120 - - - -

Total 7420 2420 - - 5000

Note: 1 Disposal method for liquid effluent and solid hazardous waste, Details of scrubbers installed for controlling process emissions.

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Product : FORMALDEHYDE (37%) Kg Per Day : 10,000

Stage: 1 Per Month : 300 Tonnes

Name of The Raw Material

Input qty. in kg / Batch

Recycle qty. in kg / Batch

Liquid Effluent in kg / batch

Solid Waste in kg / batch

Emissions in kg / Day

Output in kg / Day

Methyl Alcohol

(Methanol) 5000 - - -

DM Water 3500 - - -

AIR (N2 & O2) 15000 - - - N2 + O2

13300

FORMALDEHYDE (Product) 10000

Note: 1 Disposal method for liquid effluent and solid hazardous waste, Details of scrubbers installed for controlling process emissions.

No Liquid Effluent.

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Diethyl Phthalate (DEP) is a colourless oily liquid with a slight isomatic odour. It is

commonly used in the production of plastic to give flexibility to the production. It is also

used in insecticides, mosquito repellents and cosmetics such as hair sprays, nail polish.

It is also used in detergents, after shave lotions and skin care preparations. Used also

extensively by Agabathis manufacturing industries.

(See next chapter)

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MANUFACTURING PROCESS

Two main raw materials used are:

i) Phthalic Anhydride

ii) Industrial Ethyl Alcohol

Required quantity Ethyl Alcohol - slightly excess - is charged to the Reaction kettle from

overhead feed tank. Measured quantity of Phthalic Anhydride and Catalyst –

concentrated sulphuric acid or Para Toluene sulphuric acid PTSA - are then added

under constant stirring. Reactants are then heated to desired temperature by steam.

During reaction water is produced which has to be removed continuously to facilitate

completion of reaction. Water vapour along with ethyl alcohol vapour are condensed

and the condensate is fed to a Distillation Column to separate the Ethyl Alcohol and

water. From the top of the Distillation Column Ethyl Alcohol Vapours are taken to a

Condenser, condensed and partly returned to the column as reflux and rest cooled and

taken to Receiver, from where it is taken back to the Reaction Kettle. Water is removed

from the bottom of the Column.

When the reaction is complete, as judged from the Acid value of the production,

unreacted Alcohol is removed by distillation and recycled in the next batch.

Contents of the Reaction Kettle is then neutralised using caustic soda or sodium

carbonate, washed with water. Washing to be thorough. After settling, wash water is

drained off. Contents of the Reaction Vessel - Crude DEP - is then heated under

vacuum to remove traces of water. Stripping steam is sometimes admitted to the

Reaction Vessel to remove any adour. Contents are then cooled using cooling water in

the limpet coil and collected in the receiver for packing.

At times, DEP may have to be treated with activated carbon for removal of any colour.

After this it is filtered and taken for storage.

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#!" MANUFACTURING PROCESS

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Raw materials used in this process for the production of Formaldehyde are Methanol

(Methyl Alcohol – CH3OH) and DM water. Formaldehyde is produced by Catalytic

Vapour Phase dehydrogenation of Methanol and the hydrogen librated reacts with

Oxygen to form water. Main reactions are as follows :

CH3OH HCHO + H2

H2 + (O) H2O

Dehydrogenation reaction is endothermic and the second reaction is exothermic, net

result being liberation of heat. This heat is used for generating steam required for the

process. Another reaction which might take place in a smaller scale

HCHO CO + H2

CO + (O) CO2

Methanol from Storage Tank is pumped to the Overhead Feed Tank . DM water from

the DM Water Tank is taken to the Overhead DM water Feed Tank . Methanol and DM

water from the respective Overhead Feed Tank is taken to the Mixer in correct

proportion from where it is pumped to the Vapouriser . Vapouriser is maintained at a

specific temperature and air is purged through it by Air Blower . Air carries the

Methanol-water vapour out of the Vaporisor.

./.

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: II - 2 :

The Methanol-water vapours mixed with air is super heated in a Superheated before

entering the Reactor . Catalyst (Silver granules) is kept in the top portion of Reactor.

The Methanol-water-air mixture passes through the bed of catalyst, when the

conversion of Methanol to formaldehyde takes place and also side reactions which

produce C02, CO and water. The catalyst bed is maintained at a temperature of around

600�C by controlling process parameters. The gases leaving the catalyst bed-

formaldehyde, C02, CO, water vapour, unreacted Methanol, O2 and Nitrogen - at a

temperature of around 600�C are cooled in an inbuilt shell and Tube Heat Exchanger,

by water. Here gases are cooled to around 150�C and steam is produced. The steam

produced is separated in Steam Separator and used in the process.

The gases leaving the Heat Exchanger are further cooled in Shell & Tube Coolers ) to

around 65-70�C before admitting to Absorber, where they are scrubbed with dilute

formaldehyde solution. 37% formaldehyde solution is drawn out from the bottom of

Absorber and sent to Receivers. Heat of solution produced in the Absorber is removed

by cooling the circulating solution in Cooler . Finally the gas is scrubbed with pure DM

water in the Circulation Tower and the tail gases are exhausted to atmosphere.

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Table No.1 Details of Water Consumption

Note: # - Fresh water, * - ETP treated water,

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Table No.2 Details of Effluent Generation

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Sr. No. Description Water Consumption (M3/Day)

1. Domestic #2 2. Industrial a. Processing #5

b. Washing #1 d. Cooling 40 (#33+*7) e. Boiler Feed #5 f. D.M. Plant water for backwash #1 Industrial Total 52 (#45+*7)

3. Other (Gardening) *2 • Grand Total 56 (#47+*9)

Sr. No.

Description Effluent Generation (M3/Day)

1. Domestic 1.5 2. Industrial a. Processing 3

b. Washing 0.8 d. Cooling Tower blowdown 4

e. Boiler blowdown 0.5 f. D.M. Plant back wash 0.9

Industrial Total 9.2

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