Environmental Standards for Coal based Thermal...
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Transcript of Environmental Standards for Coal based Thermal...
Environmental Regulations for
Coal based Thermal Power Plant
Dr. S.K. Paliwal, Scientist DCentral Pollution Control Board
Delhi , [email protected]
Fast Growth, but still substantial
development needed in power sector
7th largest economy in the world by nominal GDP; 3rd largest by GDP
in PPP terms
One of the fastest growing economy
Accounts for 4.1% of world’s energy consumption
Energy demand in India will continue to grow rapidly over the next
couple of decades due to:
Rapid rate of growth
High urbanization levels
An aspiring and growing middle class and a generally
modernizing society
Low per capita electricity consumption (1010 KWh)
Indian Power Sector
0
20000
40000
60000
80000
100000
120000
140000
160000
180000
200000
Hydro Coal Gas Diesel Nuclear Renewable
42783.42
185172.88
24508.63
993.535780
38821.52
Capacity, MW
Environmental IssuesUse of high ash content coal in power generation leads to the followingenvironmental problems:
Air Pollution
• Emission of particulate matter (dust)
• Emission of sulphur dioxide and Oxides of Nitrogen
• Green House Gas Emissions
• Emission of Mercury (both gaseous and in ash)
• Fugitive emission of suspended particulate matter from CHP, Wagon Tripler
and ash pond
Water Pollution (due to higher water consumption)
• Cooling water discharge
• Ash pond effluent
Solid Waste ( use of high ash containing coal)
• Large volume of coal ash generation (Flyash & Bottom ash)
• Large land requirement for ash disposal
Estimated Sulphur dioxide emission(Industrial sector wise)
Estimated mercury emission (Industrial sector wise)
• Mercury Emission : estimated using emission factor 0.56 with av. HG content in coal 0.14 mg/Kg
Evolution of Emission Standard for Power Sector
1984
PM : 350 mg/Nm3
: 150 mg/Nm3
1989
Stack Height : H= 14 (Q)0.3 220m
2002 : Use of
beneficiated coal
2003
PM : 50 mg/Nm3
: 100 mg/Nm3
Stack Height : 220 m
275m
2015 (effective from 2017)
(PM, SO2 & NOx)
Selected countries emission
standards for coal fired power plants
Country Time Period
NOx ,mg/Nm3 SO2,mg/Nm3 PM ,mg/Nm3
existing new existing new existing new
Australia 800 200 80
China hourly 100 50 200/50 35 30/20 10
Germany daily 200 150 200 150 20 10
India Cont. 600/300 100 600/200 100 100/50 30
Indonesia 850 750 750 750 150 100
Japan 410 200 200 100 50
South Africa
Cont. 1100 750 3500 500 100 50
Thailand 820 410 2002 515 180 80
USA daily 135 95.3 185 136 18.5 12.3
EU Cont. 200 150 200 150 20 20
Present level of emission from
existing thermal power plants Parameter Concentration
Particulate matter,
mg/Nm3
30-350
Sulphurdioxide
( SO2), mg/Nm3
800-1200
Oxide of Nitrogen
( NOx) (mg/Nm3)
200-700
Mercury (mg/Nm3 )0.005 -0.0185
Water Consumption *,M3/MWh > 4.00 M3/MWh70-100 M3/MWh ( OTC)Few plants achieved zero discharge
New emission Standards notified
on 07.12.2015
Categorisation of plant based on the
year of commissioning
Category Number of units
1 Plants installed before the
year 2003
302 (59652 MW)
2 Plants installed after the
year 2003
>279 (125348 MW)
Available Technologies
Pollutant Existing approach Future technologies to be adopted
WaterConsumption
Once through / cooling towerwithout recyclingAsh pond effluent recycling sincethe year 2005 onwards
Cooling tower with recycling of effluentwith RO system
Ash pond effluent recycling from day one
Particulate matter
Electrostatic precipitator( ESP)with efficiency of 99.6%Use of beneficiated coal
Electrostatic precipitator with efficiency of99.9% / Hybrid ESP/ bag filterCompulsory use of beneficiated coal
SO2 Dispersion in larger area byproviding Tall stack height
Flue gas Desulphurisation with 90% SO2reduction in emission
NOx Low NOx burners Low NOx burners & two layer of Over fireAir/ Selective Catalytic Reduction/Selective Non Catalytic reduction with90% efficiency
Mercury No control Will be controlled as co- benefit with SO2and NOx control technologies
Challenges before the Power
Industry• Non availability of space/land in the plants installed prior to
31.12.2003 to retrofit :• Cooling tower ( CT) ( 25% of total capacity )
• FGD ( already asked to provide space for unit size 500 MW and above)
• ESP ( Possible to increase SCA/ conversion into hybrid ESP)
• Two years’ time for implementation of new norms will not be adequate
• Non availability of proven technology for control of NOx
• Availability of Lime and Disposal of Gypsum
• Substantial increase in tariff due to implementation of Norms
Strategy for Implementation of
Standards
• Preparation of Phasing out plan for vintageplants having low PLF and higher Heat rate
• Submission of time bound action plan for retrofitof ESP
• Finalisation of specification and preparation ofplan for installation of FGD wherever required
• Preparation of action plan for control of NOxeither by boiler tuning /optimisation as the casemay be.
Expected Environmental
Benefits
1. Reduction in PM, sulhurdioxde and Oxide of
nitrogen by about 40, 48 & 48 % respectively
which inturn will help in improvement in AAQ in
and around thermal power plants.
2. Reduction of mercury emission by about 60%
3. Limiting the use of water in thermal power plant
will lead to reduction in water consumption by
about 40%. Thermal power plant is one of the
water intense category ( 70% of total Industrial
water is consumed in Power sector).