Environmental Regulations for

Coal based Thermal Power Plant

Dr. S.K. Paliwal, Scientist DCentral Pollution Control Board

Delhi , Indiapaliwalsk@yahoo.com

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).