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Process related aspect of Cleaner Production

"A Case study on two important products".

Dr. MAHENDRA SADARIASAN ENVIROTECH PVT. LTD.

AHMEDABAD

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Meaning of waste

Waste is nothing but undesirable byproduct

generated from process arising from

inefficiency of the process.

Two examples were studied for innovation in

production process by way of waste exchange

and improving the efficiency of unit operations.

Innovations not only improve wastewater

characteristics or reduce the waste but also

increase the yield in terms of quantity and

quality.

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Important point for Cleaner mechanism

•Good housekeeping

•Input materials

•Better process controls

•Equipment modification

•On site recycling and material recovery

•Energy conservation

•Environmental Benefit

•Commercial benefit

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Chemical reaction of H. Acid

H2SO4

SO3H SO3H

SO3H

SO3H

SO3H

165oC

Sulphonation

Nitration

HO3S SO3H HO3S SO3H

SO3H HO3S NO2

SO3H

SO3HHO3S

Conc. HNO3/H2SO4

Neutralization

HO3S SO3H

HO3S NO2

CaCO3+Na2SO4

NaO3S SO3Na

NaO3S NO2

+ CaSO4

H2SO4

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Chemical reaction of H. Acid

NaO3S SO3Na

NaO3S NO2

Fe+HCl

NaO3S SO3Na

NaO3S NH2

Reduction

Fusion

NaO3S SO3Na

NaO3S NH2

NaOH

NaO3S SO3Na

ONa NH2

Isolation

NaO3S SO3Na

ONa NH2

HO3S SO3H

OH NH2

H2SO4

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INPUT KG OUTPUT KG

Naphthalene 1400

Sulphuric acid 2000

Water 157

Oleum 3000

Nitric acid 1000 NOx

(Scrubbuing)-ETP 350

LSP 5000

Glauber salt 3570 CO2 2200

Water 8570

Water 7140 Gypsum(73%) 13180

(Sludge)

Steam 5430

CI Powder 930 Wastewater 3930

Acetic acid 60

Soda ash 430

Iron Sludge(70%) 1950

Water 5710 (Sludge)

Rec.water 8570

Caustic Flakes 1785 Methenol(Rec) 515

Methanol 600

Spent acid 8930

Sulphuric acid 1000 SO2 708

Water 4750 SBS(450 KG)

Mother liquor 27435

MME + INC

Mother liquor 957

Wet cake(60%) 1667

Mass balance 61462 61462

Mass balance of H - Acid

Sulphonation

Nitration

Neutralizer

Filtration

Reduction

Filtration

Evaporator

Fusion

Isolation

Filtration

Centrifuge

H - Acid

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Chemical reaction of Vinyl Sulphone

NH2

+ CH3COOH

NHCOCH3

+ H2O

Acetylation

Sulphonation

NHCOCH3

+ 2ClSO3H+ SOCl2

NHCOCH3

SO2Cl

+ HCl + SO2

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Chemical reaction of Vinyl Sulphone

NHCOCH3

SO2Na

Condensation

+ + H2SO4

NHCOCH3

+ Na2SO4 + H2O

Esterification

+ H2SO4

NH2

OHO2S

O2SOSO3H

+ CH3COOH

Reduction

NHCOCH3

SO2Cl

+ 3NaOH + NaHSO3

NHCOCH3

SO2Na

+ Na2SO4+ NaCl+ 2H2O

O

H2C CH2

NHCOCH3

OHO2S

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INPUT KG OUTPUT KG

Acetanilide 555

Chloro sulphonic acid1470 HCl 320

Thinoyl chloride 500 S.B.S. Slurry 340

Ice 3300 Mother liquor 2115

Water 2200 Wash water 3110

SBS slurry 340

SBS 125 Salts 315

Caustic lye 660

Ethylene oxide 250

Spent acid 830

Wash water 1670 Mother liquor 1670

Wash water 2575

Wash water 600

Sulphuric acid 345 Acetic acid 200

Final Product 1000

Total 12245 12245

Mass Balance for Vinyl Sulphone

Sulphonation

Drownings

Reduction

Ethoxylation

Condensation

Centrifuge

Drying

Esterification

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Waste exchange mechanism

SulfonationChlorosulfonation

Nitration

Neutralization

Filtration

Reduction

Drowning

Filtration

Filtration

Condensation

Clarification

Reduction

Amino Conc.

Filtration

Alkali fusion

Packing

Drying

Isolation

Filtration

Drying

Esterification

Packing

Acetic Acid

NaHSO3

Dil. H2SO4

Na2SO4

H. AcidV.S.

Synergy in manufacturing of

H. Acid and V.S.

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Why Recycling •Conserve the Natural Resources

•Reduce Energy Conservation

•Save clean Air & Water

•Save money

•Saving due waste recovery

•Saving due to reduced treatment

Traditional Production•Material loss

•Operational cost

•Personal cost

•Investment cost

•Public Authorities Proceeding

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Resource RecoveryDue to above waste exchange and recovery of by product, we

get spent Sulphuric acid (25-30 %) and acetic acid (92 %) as

by-product, which is reused/sold to actual users.

Proper operating air pollution control systems, we get HCl (25-

28%), where the unit has also provided adequate scrubbing

system and solution obtained at the end of scrubbing system

is collected and reused/sold.

There is also recovery of Glauber salt from the isolation of H.

Acid and condensation step of VS product, which can be

recovered by Multi effect evaporator and reused/sold to actual

users.

Now a days gypsum and iron sludge is recovered from H-acid

manufacturing, which is sold to cement manufacturers.

Considering above cleaner concept, pollution load can be

reduced drastically from production of H. Acid and Vinyl

sulphone production.

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Reduction in Wastewater

Sr. No.

Products Wastewater generation, kL/Tone Reduction in

volume percent

Conventional process

After adoption of

waste exchange

mechanism

Difference

I. H. Acid 41242 4280 36960 90

II. Vinyl Sulphone 11245 7955 3290 29

Total 52487 12235 40250 77

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Important point for Cleaner mechanism

•Good housekeeping

•Input materials

•Better process controls

•Equipment modification

•On site recycling and material recovery

•Energy conservation

•Environmental Benefit

•Commercial benefit

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Process modification in Dyes Production

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Chemical reaction of Reactive Black-5

NH2

SO

SO3HO

O

+ NaNO2 + 2HCl NaCl2H2O+

N

SO

SO3NaO

O

+

N Cl

N

SO

SO3NaO

O

N Cl

+

NH2 OH

HO3S SO3H

+ 4NaHCO3

NH2 OH

NaO3S SO3Na

NNN N

+ H2O+CO2 2NaCl+

Vinyl Sulphone

Diazotization

Coupling

H. Acid

Reactive black-5

2

SO

SO3NaSO

NaO3S

O

O

O

O

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Following process steps are important

to produce proper dyes

•Known quality of raw materials

•Possible mole to mole reaction

•Optimal pH control

•Optimal Temperature control

•Standardized the reaction efficiency and try to

continuous improve it

•Avoid filtration of dye if possible and adopt

spay drying in house or out sourcing, which

will be helpful to reduce the loss of dye and

reduce the pollution load on environment

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Typical mass balance of Black-5 TYPICAL MATERIAL BALANCE FOR –1000 Kgs.

INPUT INPUT

R.M. MASS

V.S. 500 Kgs.

HCL 200 Kgs.

NaNO2 125 Kgs.

Water+Ice 2075 Ltr

Vol.

2900

R.M. MASS

H.Acid 350 Kgs.

Soda bicarb 150Kgs.

450

FINAL

VOL.

3330 Ltr.

EVP

1330 Ltr.

Product = 1000 Kg. S. D.

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What is happening if reaction is not

takes place in proper way?

• If mole ration of diazoniam salt is higher than

the active aromatic compound like-H-Acid …..

Greenish tone will develop

• If mole ration of diazoniam salt is lower than

the active aromatic compound like-H-Acid …..

•Reddish tone will develop

• If Optimal Temperature control not maintained

•Proper dying not takes palace and dye will

washed with washing of cloth

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Environmental and Economic Benefits

Raw Materials RM

requirement in

kg

Cost on

M:M

Basis

Cost on

conventional

basis

Cost

benefit in

Rs.

Environmental

Benefits

Diazonium salt

Vinyl Sulphone

(MW-281)

500 69000 69000 - Raw materials

savings and

reductions in

wastewater

discharges.

Sodium Nitrite 125 3625 4350 725

HCl 200(30%) 400 600 200

Water + Ice 3500 Ltr - - -

Azo coupler

H. Acid

(MW-319)

283 Kgs. 60845 63675 2830

Soda

bicarbonate

150 Kgs. 2250 2625 375

4130

Product: - Black -5, Batch size:-1000 kg

•Better rate of finished products due to better quality

•Reduction in Energy Consumption

•Reduction in Manpower

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Environmental and Economic Benefits

Bach size in kg(Finished product)

Solid Concentration

Drying cost benefit

Cost benefit

Environmental Benefits

1000 30% Rs 8.33/Kg - Resource conservation in terms energy saving 2000 32% Rs 7.81/Kg Rs.1.22

5000 35% Rs 7.15/Kg Rs.1.18

10000 37% Rs 6.76/Kg Rs.1.57

Cost benefit v/s Batch size

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Why is the diazotization reaction done at

zero to five degrees centigrade?

The reaction is done at zero to 5 degrees centigrade

because the diazonium ion is so reactive. It reacts

with water above 5 degrees giving off nitrogen gas.

Also, running the reaction at or near zero degrees

Celsius limits the formation of side products and

prevents thermal decomposition.

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Why Optimal pH control at dye plant is

required?

Two side coupling is required. First at Acidic pH

around 2.5 pH.( check completion of st coupling by

testing in lab sample against standard sample).

Increased the pH by addition Sodium bicarbonate up

to 5.0 as fast as possible so that second coupling at

0 to 50C will take place.

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THANKS……….