Control of Emissions from Power Plants/Large Scale Industries – Present and Future Approach : Control of Emissions from Power Plants/Large Scale Industries – Present and Future Approach By: Lalit Kapur, Senior Environmental Engineer Central Pollution Control Board
Control Strategies for: : 1. Power Plants, Cement, Aluminium and Integrated Iron & Steel are the major sectors from infrastructure development of the country. However, these are one of the major polluting in nature.
Besides Green House Gas Emission, SO2, NOx, Fluoride & CO are the critical pollutants emitted from these industries.
To contain emissions of these pollutants, environmental standards have been developed.
Implementation of environmental standards has been taken up at National & State Level. To give impetus in implementation of environmental standards National Task Force for each industrial section have been constituted.
Specific measure such as use of clean fuel, clean process technologies/alternate control systems have been suggested for each individual industrial section separately to tackle the serious issues related to air pollution, water pollution and solid waste disposal. Guidelines have also been evolved to deal with problem of flyash, (spent pot lining) and coke oven emissions. Control Strategies for:
Development of Environmental Standards : Development of Environmental Standards Power Plants
Power Sector : A Profile : Power Sector : A Profile Seventy one per cent of total installed capacity of electricity production is based on coal and gas in the country.
81 coal based thermal power plants comprising of 57799 MW electricity generating capacity as on March 2002
More than 200 million tonnes of coal with ash contents 35-45% is consumed in Thermal Power Plants
Nearly 90 million tonnes per annum coal ash is generated.
Power Plants
Environmental Issues : Environmental Issues Use of high ash content coal in power generation leads to the following environmental issues :
Air Pollution
Emission of particulate matter (dust)
Emission of sulphur dioxide and Oxides of Nitrogen
Green House Gas Emissions
Water Pollution
Cooling water discharge
Ash pond effluent
Solid Waste
Large volume of coal ash generation
Power Plants
Emission Standards For Thermal Power Plant : Emission Standards For Thermal Power Plant Depending upon the requirement of local situations, which may warrant stricter standards as in case of protected areas the State Pollution Control Boards and other implementing agencies within the provisions of the EPA, 1986 may prescribe limit of 150 mg/Nm3 irrespective of the generation capacity of the plant. Power Plants
Stack Height Requirement : Stack Height Requirement In order to proper dispersion of SO2 emissions from thermal power plants, stack height criteria is adopted in the country. However, for larger capacities of boilers (500 MW and above), space provision for installing FGD system has been recommended. --------------------------------------------------------------------------------------------
Power generation Stack height (metre)
Capacity
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Less than 200/210 MW H= 14(Q)0.3 where Q is emission rate of SO2 in kg/hr and H is stack height in metre
200/210 MW or less than 220
500 MW
500 MW and above 275
-------------------------------------------------------------------------------------------- Power Plants
Conventional Practices for Control of Pollution : Conventional Practices for Control of Pollution Air Pollution:
Particulates: High efficiency Electrostatic precipitator
Gaseous emission: Dispersion through tall stacks
Water Pollution
Cooling Water Discharge: Once through with long channels/cooling tower
Ash Pond effluent: Settling ponds
Solid Waste
Coal ash: Dumped into ash ponds.
Emphasis is being given to utilize ash for the manufacture of builder products, cement, construction of highways, filling of 100 lying area and minefill etc. Power Plants
Future Technologies for Pollution Prevention & Control in Power Section : Future Technologies for Pollution Prevention & Control in Power Section Adoption of Clean Coal Technologies (CCTs)
To meet increasing demand of power with minimal environmental impact for sustainable development, adoption of clean coal technologies with enhanced power plant efficiency, use of washed coal, efficient pollution control systems and proper by-product and waste handling & utilization, is necessary
.
Clean Coal Technologies
Pre-combustion Technologies: Ash sulphur and other impurities can be reduced (coal benefaction) from the coal before it is burned.
Combustion technologies Generation of emissions of SO2, NOx & CO2 can be
FBC(CBFC, AFBC & PFBC) and IGCC minimised by adopting improved combustion technologies.
Post combustion technologies End of pipe treatment (installation pollution control equipments such as ESP, DENOx & De SOx systems Power Plants
Use of Beneficiated Coal : Use of Beneficiated Coal Ministry of Environment & Forests, vide notification no. GSR 560(E) & 378(E) dated September 19, 1997 and June 30,1998 respectively made mandatory use of beneficiated/blended coal containing ash not more than 34 per cent on annual average basis w.e.f. June 2001 (extended to June, 2002) in following category of power plants
Power plants located beyond 1000 km from pit head
Power plants located in critically pollutied areas, urban areas and ecologically sensitive areas.
The Power Plants using FBC (CFBC, PFBC & AFBC) & IGCC CCTs are exempted to use beneficiated coal irrespective of their locations.
Power Plants
Requirements Of Beneficiated/blended Coal : Requirements Of Beneficiated/blended Coal Out of 81 coal based Thermal Power Plants, 39 plants are required to use beneficiated coal not containing ash more than 34 per cent w.e.f. June 2002
As per Central Electricity Authority (CEA) estimation, the requirement of coal for existing and the plants to be installed under Ninth Plan would be 85.46 million tonnes per annum.
Coal India Ltd. would able be meet the requirement of 68.48 million tonnes per annum coal from their sources (by existing washeries and blending of domestic coals). The remaining quantity could be met by blending imported and domestic coal at coastal Thermal Power Plants and changing the linkages suitably. Power Plants
Thermal Power Plants Required to use Beneficiated Coal : Thermal Power Plants Required to use Beneficiated Coal Power Plants
Thermal Power Plants Required to use Beneficiated Coal : Thermal Power Plants Required to use Beneficiated Coal Total coal consumption based on 2002-2003 data upto ix plan 85.46 MTPA
* Revised based on data provided by SEBs/utilities
UA : Urban Area, CPA : Critically Polluted Area, SA: Sensitive Area and IC: Imported Coal Power Plants
Coal Beneficiation Status : Coal Beneficiation Status Coal Beneficiation Plants under operation
Piparwar Washery Orissa 6.5 Mt/y of raw coal
Bina Deshaling plant MP 4.5 Mt/y of raw coal
Bilaspur washery MP 2.5 Mt/y of raw coal
Girdih washery Bihar 2.5 Mt/y of raw coal
Kargali washery Bihar 1.5 Mt/y of raw coal
Dipika washery Orissa 8.0 Mt/y of raw coal
Coal Beneficiation Plants under Planning
Talcher
Ib Valley
North Karanpura Power Plants
Setting up of Coal Washeries “Suggestions” : Setting up of Coal Washeries “Suggestions” To find the options/mechanism for setting up of coalwasheries for non coking coals :
Coal India will set up its own washery
State Electricity Board to set up its own washery
Coal India to ask private entrepreneurs to set up washeries for CIL and taking washing charges
State Electricity Board to select a private entrepreneur to set lup a washery near pit-head Power Plants
Clean Coal Combustion Technologies : Clean Coal Combustion Technologies Super Critical Technology
Larger unit size (more than 500 MW)
Higher thermal efficiency (of 5% and above)
Low gaseous & soots emissions
Fluidised Bed Combustion (CFBC/PFBC/AFBC)
Can burn wide range of coals and other fuels such as pet coke, lignite etc.
Higher thermal efficiency (>40%)
Lower NOx emissions
Low CO2 emissions
Insitu SO2 control
Sizes upto 250 MW commercially available indigenous
Cont’d Power Plants
Slide17 : Power Plants Integrated Gassification Combined Cycle (IGCC)
Through ash developing stage
Limitation on availability of larger unit size
High thermal efficiency (>45%)
Sulphur dioxide removal upto 99%
NOx reduction by 90%
Low CO2 emission
Post Combustion Technologies
High efficiency electrostatic precipitator
Replacement of ESP with Bag filter
De SOx and DeNOx systems
Recycling of ash pond effluents
Switching over to medium concentration slurry disposal system (MCSD) with ash concentration in slurry 40-45% for high concentration slurry disposal systems (HCSD) with ash concentration in slurry 65-72%
Utilization of Flyash (at present about 19% coash ash is utilized for manufacture of cement, bricks, construction of road, bulk filling of mines etc.
Cement Sector: Profile :
India Ranks World's 2nd largest cement producing country
No. of Large Cement Plants in the country - 113
Total Annual Installed Capacity - 110.10 Million Tonnes (As on March 2000)
Annual Cement Production - 94.21 Million Tonnes
(As on March 2000) Cement Sector: Profile Per Capita Consumption of Cement (1999) Cement Industries
Environmental Issues in Cement Sector : Environmental Issues in Cement Sector Uncontrolled fugitive emission
Raw Material Storage
Loading/Unloading Operation
Material Transfer Point
Continuous dust monitoring system & its calibration
Industrial solid waste utilisation in cement manufacturing
Flyash
Blast Furnace Slag
Lime Sludge
Phospho Gypsum
Cement Industries Cont’d
Slide20 : Cement Industries Use of Hazardous Waste in Cement Kiln
Ø Reduction of Green House Gases
Reduction in power consumption
Reduction in coal consumption
Promotion of Energy Efficient Technology
Ø Waste heat recovery from kiln & clinker cooler exit gases
Ø Energy Conservation
Use of petroleum coke as fuel in kiln – Environmental implication (emission of SO2, V, Ni, PM10)
Sources of Dust Emissions : Sources of Dust Emissions Point Sources
Stack attached with kiln,
Stack attached with Raw Mill,
Stack attached with Clinker Cooler,
Stack attached with Coal Mill,
Stack attached with Cement Mill,
Fugitive Sources
Open air handling & storage of raw materials & clinker
Transfer Points
Leaking Joints
Loading & unloading operation
Vehicular movement on unpaved roads Cement Industries
Dust Generation at various sections in Cement Plant : Dust Generation at various sections in Cement Plant Cement Industries
Emissions of Pollutants : Emissions of Pollutants SO2 Emission from kiln
Formation Mechanism
*Oxidation of sulphur compounds present in raw material & fuel (300-600C)
Emission Range: 300-2300 mg/Nm3 (Coal based kiln)
Emission of SO2 may be very high in case of Pet Coke based kiln
NOx Emission From Kiln
90% of NOx is in the form of NO
Formation Mechanism: Thermal NO & Fuel NO
Emission Range 200-2500 mg/Nm3
Literature indicates wide variation in emission range
NOx is less in Modern Pre-calcinater Kilns Cement Industries
Selection of Air Pollution Control Equipment :
Size of dust particles
Flue gas characteristics
Collection efficiency
Emission standard
Techno-economic Feasibility of Air Pollution Control Equipment
Selection of Air Pollution Control Equipment Cement Industries
Recommended Air Pollution Control Equipment for different Sections : Recommended Air Pollution Control Equipment for different Sections Cement Industries
Fugitive Emission Control :
Fugitive dust is 10-30% of total emission
Local exhaust ventilation system
Water spray
Proper House Keeping
Enclosed storage facilities (silo, dome-shaped building) to store raw materials, additives, coal, clinker, flyash Fugitive Emission Control Cement Industries
Emission Standards in India : CPCB/SPCB may fix stringent standards, if required Emission Standards in India Cement Industries
Emission Standards in other Countries : Emission Standards in other Countries Cement Industries
Utilisation of Industrial Solid Waste in Cement Manufacturing : Flyash (solid waste from TPP)
Blast Furnace Slag (Solid Waste from Iron & Steel Plant)
Phospho-gypsum (Solid Waste from Fertilizer Plant)
Lime sludge (Solid Waste from Pulp & Paper Industry) Utilisation of Industrial Solid Waste in Cement Manufacturing Cement Industries
Pollution Control Implementation Status :
Constitution of National & Zonal Task Forces (1986)
Prosecution of Recalcitrant units
Notification No. 66, dated 12.02.92,
Establishment before 1981 : Comply by 31.12.93
Establishment after May 1981 : Comply by 31.12.92
CPCB issued direction under Section 5 of EPA, 1986 Pollution Control Implementation Status Cont’d Cement Industries
Slide31 :
Complying units : 58
Non complying units : 16
Closed units : 14
Status Awaited : 25
Kiln + Raw Mill : Bag Houses (emission 50 mg/Nm3)
Multicyclone with clinker cooler : Replace by ESP
Kiln ESP Tripping : High CO (Fluctuation in coal quality)
Bed blending system : Reduces variation in coal quality
: Reduces Problem of high CO
: ESP operation more stable Cement Industries
New Initiatives taken/Proposed by CPCB for Cement Industry : Constitution of National Task Force
Effective implementation of standards through Task Force
Engineering Design parameters of A.P.C.E.
Fugitive Emission control – new regulation and standard for fugitive emission and monitoring protocol being finalized
Pollution load standards for cement mill, kiln and clinker cooler instead of concentration limit
Emission standard for SO2, Ni and V for petroleum coke based cement kiln
Proper calibration of Opacity Monitor New Initiatives taken/Proposed by CPCB for Cement Industry Cement Industries
Slide33 : Proper record keeping of ESP / Bag filter
Regular interaction meeting of National Cement Task Force (NCTF) with cement industries and SPCB to discuss & sort out technical issues
Common consent (Air, Water) for cement industries
Incentive for using flyash in cement making
Effective noise pollution control from cement industries
Material balance and Environmental Audit in cement industry
Defaulter list in CPCB web site Cement Industries
Aluminium Sector: Present Capacity and Future Expansion* : Aluminium Sector: Present Capacity and Future Expansion* *Based on information of 1999-2000
# Expansion complete Aluminium Industries
Environmental Issues : Environmental Issues Ambient Fluoride levels around Smelter
Fluoride emissions from Smelters
HC/PAH emissions from Smelters and Anode plant
Disposal of Spent Pot Lining
Presence of leachable cyanide and fluoride
Disposal of Red Mud
Presence of alkalinity
Mercury discharge from Gallium plant
Aluminium Industries
National Emission Standards : National Emission Standards Note: Q-Emission of SO2 in kg/hr, H-Stack Height in m
Source: MoEF notification GSR 742 (E), dated 30.08.1990 Aluminium Industries
Fluoride Emissions : Fluoride Emissions *kg/t of aluminum
# MoEF condition – 2.5 kg F/t after expansion Aluminium Industries
Spent Pot Lining (1999-2000) : Spent Pot Lining (1999-2000) Aluminium Industries
Red Mud (1999-2000) : Red Mud (1999-2000) Aluminium Industries
Proposed Future Policy : Proposed Future Policy Phasing out of the Soderberg Technology
Revising fluoride emission standards and converting to Dry Scrubber
Setting up a limit for fluoride consumption per tonne of aluminium
Prescribing standards for ambient fluoride/forage fluoride
Developing emission standards for HC/PAH
Setting up a centralised SPL treatment and disposal facility
Converting to Dry methods for disposal of Red Mud Aluminium Industries
Integrated Iron & Steel Sector : Integrated Iron & Steel Sector Major Sources of Pollution:
Coke Oven and By-product Plant
Steel Melting Shop
Sintering Plant
Blast Furnace
Refractory Material Plant
Captive Thermal Power Plant Iron & Steel Industries
Emission Standards : Emission Standards Stack Emissions Iron & Steel Industries
Slide43 : Iron & Steel Industries Cont’d
Slide44 : Iron & Steel Industries
Current Practices and Future Requirement for Control of Pollution : Current Practices and Future Requirement for Control of Pollution Iron & Steel Industries Cont’d
Slide46 : Iron & Steel Industries
Problems in Achieving the Standards : Problems in Achieving the Standards Air-cooled self-sealing doors.
The hydrojet cleaning system shall be provided for the door and door frame cleaning with a facility of hydrojet pressure of 600 kg/cm2.
Provision of water sealed AP covers should be provided.
To provide aspiration through high pressure ammonia liquor (HPLA) injection in goose neck and emissions should be transferred directly to gas collecting mains.
To reduce generation of emissions during coal charging, the charging should be accomplished with hermetically sealed charging sleeves and screw feeders in charging car.
Provision of new charging car with magnetic lid lifter in the charging car alongwith lid and frame cleaning should be made.
The coke pushing emission should be treated in stationary land-based system with collection hood and wet scrubbing unit for gas cleaning. The height of chimney discharging the cleaned gases must ensure proper dispersion of gaseous pollutants.
Computerized combustion control and computerized moisture control system to be provided. SAIL coke oven batteries are old batteries, most of which have been installed alongwith the installation of Steel Plants. 22 batteries are in operation at present. The main problems faced by the industry is due to non installation of the following pollution control units: Iron & Steel Industries