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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……….
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