Facts of Caustic Soda Industry 95% of world chlorine production is by this industry
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Transcript of Facts of Caustic Soda Industry 95% of world chlorine production is by this industry
Standards and Regulations for discharge of liquid effluents and Gaseous Emissions related to chlor
alkali industry
Shri Paritosh Kumar ,AD & Shri Dinabandhu Gouda, SEECENTRAL POLLUTION CONTROL BOARD
DELHI – 110 032
Facts of Caustic Soda Industry
1. 95% of world chlorine production is by this industry
2. The caustic soda industry has attracted particular attention of pollution control authorities world over.
3. The concern is due to the release of mercury into the environment from industrial unit using mercury cell process (a polluting process) for the manufacture of caustic soda.
4. Caustic soda is mainly produced by two electrolytic processes – Mercury Cell and Membrane Cell Technology.
5. Stoichiometrically 1.46 MT salt (100% NaCl) and 0.45 MT water is converted to produce 1 MT of caustic soda, 0.89 MT of Chlorine and 25 kg of Hydrogen.
Caustic Soda Demand in India(%)
5. Chlorine is largely used in the synthesis of chlorinated organic compounds. Vinyl chloride monomer (VCM) for the synthesis of polyvinyl chloride (PVC) still remains the driver of chlor-alkali production in the world .
6. Chlorine is used in 98% of the water treatment plants in the world.
Operational Status of Caustic Soda Plant in India
No. of Caustic Soda Plants in Operation :
Mercury + Membrane Cell Plants : 03(i) Atul Ltd, Gujarat(ii) Hindustan Paper Corporation, Cacher, Assam(iii)Hindustan Paper Corporation, Nagaon, Assam Mercury Cell Plants closed : 02(i) Hindustan Heavy Chemical Ltd, West Bengal(ii) Solaris Chemtech, Karnataka Membrane Cell Plants (Exclusively) : 32
Total : 37 plantsProcess Installed Capacity
(Lakh MTA)Productionin 2012-13(Lakh MTA )
Total 27.94 21.61
Trend of Technology Shift in Chlor-Alkali Sector
Energy Consumption in 5 th Generation Membrane cell•The energy consumption in a Membrane cell is of the order of 2,000–2,200 kilowatt-hours per metric tonne of caustic .•Electrode gap plays an important role in cell voltage, as the electrode gap reduces there will be an reduction in electrolyte internal resistance which lowers the cell voltage. This gap cannot be reduced to zero because of the following reasons. Risk of friction between membrane and electrodes• Special cathode coating required• Corrosion attack of fine mesh by chlorine gas penetration and stagnation• Complex and expensive manufacturing
Wastewater is generated from •Cell house, •Brine purification section, chlorine• Hhydrogen handling section • HCl manufacturing unit.•Brine sludges are one of the largest waste streams of the chlor-alkali industry.
EFFLUENT TREATMENT SYSTEM ADOPTED INCAUSTIC SODA INDUSTRIES IN INDIA
Combination of Treatment Procedures Adopted by Caustic Soda Plants:
Sodium sulphide treatmentActivated carbon bed filtration Sand filtration Ion exchange resin columns
SOLID WASTE DISPOSAL
Brine sludge generation range : 0.03 to 0.05 t/t of NaOH
Hg conc. in brine sludge : 25-235 mg/kg
Observations:
Need for vacuum dewatering system/washing of brine mud.
Need for proper storage of brine mud to avoid entry of rainwater and its spillage.
Need for proper collection and containment of brine mud.
Need for periodic monitoring around the storage/disposal areas for any spillage/percolation of mercury bearing waste.
Brine Sludge Area Before Earth Capping
Brine Sludge Area After Earth Capping
12
All the industries has been complied 12 action points out of 13 action points suggested by CREP.
Mercury emission to environment has been decreased to 0.64 gram/Ton against CREP recommendation 2 gram/ton.
Mercury consumption has been reduced to 14.91 gram/ton against CREP recommendation 50 gram/ton .
All the mercury cell plant has been planned to switch over membrane cell technology by 2012 much ahead of EU target of 2020.
CREP : Chlor-Alkali IndustryCREP : Chlor-Alkali Industry
ENVIRONMENTAL REGULATIONS
Wastewater Discharge Standards Parameter Concentration not to exceed
Total concentration of : 0.01 mg/lmercury in final effluent
· Mercury bearing wastewater : 10 Kl/ton of NaOH productiongeneration (Flow)
· pH : 5.5 to 9.0
Process Pollutants Emission limits (mg/Nm3)
Mercury process Mercury (H2 gas holder) 0.2
All process Chlorine (Hypo tower) 15
All process Hydrochloric vapor/mist (Hydrochloric acid plant)
35
Air Emission Standards
Substance Permissible limits for Mercury & Chlorine
Work zone conc. in mg/m3 (8 hrs. time-weighted avg.)
• Mercury
• Chlorine
• HCl mist
0.05
3.00
7.00
Permissible Limit for Mercury/Chlorine in Work Environmentas per the Factories Acts, 1948
Hazardous Waste Generation from Chlor-alkali Industry
as per HW(M ,H,T)Rules , 2008 Processes (Schedule-I)
o Cat:16.1: Mercury bearing sludge
o Cat:16.2:Residue sludge and filter cakes
o Cat:16.3:Brine sludge containing Mercury
SPCB to issue authorisation for collection, storage, treatment & disposal of HW.
Liquid effluent : 0.1 gm/t of Cl2 (~ 0.09 gm/t NaOH)
Emission from cell room : 1.7 gm/t of Cl2 (~ 1.55 gm/t NaOH)
Products : 0.1 gm/t of Cl2 (~ 0.09 gm/t NaOH)
Total Hg release : 2.0 gm/t of Cl2 (~ 1.82 gm/t NaOH) USEPA
Liquid effluent : 0.23 gm/t of Cl2 (~ 0.21 gm/t NaOH) –
max. for one day: 0.1 gm/t of Cl2 (~ 0.09 gm/t NaOH)
– max. avg. for 30 days
Sludge : 17 mg/kg
Leachate for solid waste : 0.2 mg/l
INTERNATIONAL REGULATIONS(Standards for Hg bearing streams)
Stream Limit for mercury
EUROCHLOR
JAPAN
Two types of requirements for effluent control in Japan:
Regulations or standards issued by the environmental agencies; and
Guidelines issued by the Ministry of Interior, Trade and Industry (MITI).
Standards for industrial discharges of mercury:
WW discharge standards for mercury : 5.0 ppb (0.005 mg/l)
Standards for water quality : 0.5 ppb (0.0005 mg/l)
Guidelines issued by MITI to all Chlor alkali plants:
All process water contaminated with mercury must receive full recycling.
Mercury cell must be phased out (5 yrs. from recycling date).
Realising problem associated with mercury based caustic soda plant, Govt. of India :
i. Issued notification under EPA 1986 for liquid effluent and gaseous emission standards for controlling mercury from stationary sources; and
ii. Recommended commissioning of new plants and expansion of Hg cell based plants not to be allowed with effect from 1986 and adopt the cleaner production process (i.e. membrane cell process). The production of caustic soda by Hg cell plant since then gradually declined.
Name of Industry
Production capacity
Date of Inspection
Complying/Non complying
Remarks
Rayalaseema Alkaliies and Allied Chemicals, Kurnool,Andhra Pradesh
Caustic soda -520 TPD
24.11.2009
Partially complying –PM-126 > 115 mg/Nm3HCl-7.5<35Cl2-9.5<15.0
Letter to APPCB to direct industry to take necessary action
SIEL chemical complex ,Patiala,Punjab
Caustic soda -250 TPD
25.06.2013
complying
Hindustan Heavy Chemicals Ltd, West Bengal
Caustic soda-42 TPD
19.11.2009
Not complying. Mercury released to environment is 5 gm/ton >2 gm/ton
CPCB issued direction u/s 18 (1) b to WBPCB and Closure notice issued by WBPCB
Name of Industry
Production capacity
Date of Inspection
Complying/Non complying
Remarks
Aditya Birla Chemical Ltd, Renukoot ,UP
Caustic soda - 220 TPD
21.04.2010 complying
Travancor Cochin Chemicals ,Cochin,Kerala
Caustic soda -175 TPD
21.09.2009 Non complyingCl2- 124>15 mg/Nm3HCl-339 >35 mg/Nm3
CPCB issued direction u/s 18 (1) b to Kerala Board
RIL ,Dahej,Gujarat
Caustic soda-450 TPD
17.11.2009 Complying -
Shriram Chemical and Fertiliser ,Kota,Rajasthan
Caustic soda-325 TPD
17.09.2012 complying -
Name of Industry
Production capacity
Date of Inspection
Complying/Non complying
Remarks
Grasim Industries Ltd,Nagda, MP
Caustic soda - 750 TPD
22.02.2012
Partially complying
Letter to the unit to install continuous monitoring system
Gujarat Alkali and Chemical Ltd, Vadodara,Gujarat
Caustic soda -500 TPD
18.02.2011
Non complyingChloride -1873 mg/l>600 mg/l and incinerator is operating without APCD
CPCB issued direction u/s 18 (1) b to Gujarat PCB and GPCB issued direction u/s 31 A and 33 A
Lords Chlor Alkali, Alwar ,Rajasthan
Caustic soda-30 TPD
17.12.2010
Complying -
Name of Industry
Production capacity
Date of Inspection
Complying/Non complying
Remarks
Tamilnadu Petroproducts,Manali, Chennai,Tamil Nadu
Caustic soda - 225 TPD
16.12.2013
Non complyingPh-11.4>9.0SS-302>30 mg/lOil and Grease 121 >10 mg/lCl2-41>15 mg/Nm3
Direction u/s 5 issued to the unit by CPCB
DCW ,Thoothkudi,Tamil Nadu
Caustic Soda-280 TPD
22.04.2008
Non complyingPh-2.4<5.5Hg-0.02>0.01 mg/l
CPCB issued direction u/s 18 (1) b to Tamilnadu PCB and TNPCB issued direction u/s and 33 A
Name of Industry10.04.2013
Production capacity
Date of Inspection
Complying/Non complying
Remarks
Durgapur Chemicals Ltd, Durgapur,West Bengal
Caustic soda-100 TPD
18.01.2011 complying -
Aitya Birla Chemicals Ltd, Palamau, Jharkhand
Caustic soda - 550 TPD
25.09.2013 complying Letter to the unit to connect CPCB server
Jayshree chemicals Ltd, Ganjam,Odisha
Caustic soda - 150 TPD
10.04.2013 complying
Status of Caustic soda PlantStatus of Caustic soda Plant
All the Caustic Soda Plant should :
• Not by-pass any control system.
• Maintain operational parameter during start-up & shut down, like Redox meter in Hypo tower .
• Maintain desired strength of caustic concentration in HT.
• Use of good quality salt
• Provide continuous Cl2 and HCl monitoring system at all strategic location, stacks, work-zone areas and its recording on strip chart in control room.
• Issue of Brine Sludge generated from Membrane cell plants in the light of Hazardous Waste(M,H,T) Rules,2008
• Review of effluent and emission standards
• Applicability of continuous effluent and emission monitoring system
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