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Environmental Impact Assessment (EIA)

of Thermal Power Plant

By:- Vandana Bharti

Department of Environmental Engineering Ch. B.P. Government Engineering College

New Delhi (India)

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SUMMARY TABLE OF ELECTRIC POWER GENERATION

Source India Japan U.S.Coal 59.2% 21.2% 51.8%

Oil 13.9% 16.6% 03.1%

Gas 06.3% 22.1% 15.7%

Nuclear 02.5% 30.0% 19.9%

Hydro 17.8% 08.2% 07.4%

Others 00.3% 01.9% 02.2%

Ref:-CPCB-2012

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INTRODUCTION

A thermal power station is a power plant in which the prime mover is steam driven. Water is heated, turns into steam and spins a steam turbine which drives an electrical generator.

After it passes through the turbine, the steam is condensed in a condenser and recycled to where it was heated; this is known as a Rankine cycle .

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MECHANICAL DESIGN• Boiler.• Furnace.• Turbine.• Super Heater & Re- Heater.• PA,FD & ID Fan.• Cooling Tower

FUNCTION HELD IN PLANT

• Coal Flow• Steam Flow• Water Flow• Ash Handeling

FEED WATER SYSTEM

• High Pressure Heaters• Boiler Feed Pump (BFP)• Feed Regulating System• Drip & Drain System

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PLANT LAYOUT

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PROCESS Coal supplyAfter haulers drop off the coal, a set of crusher and

conveyor prepare and deliver the coal to the power plant. When the plant need coal, coal hopper crush coal to a few inches in size and the conveyor belt bringing the coal inside.

WAGON TIPPLER:It is the machine which is used to tip the coal from the

wagon. The coal tipped is directly feed to conveyor belt. Its capacity is 12 wagon per hour.

CRUSHER:It crushes the coal into small pieces. COAL MILLS:In it small pieces of coal are converted into pulverized

from.

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FURNACE:It is the chamber in which fuel burns & fire blows. BOILER DRUM: It contains water for boiling. ELECTROSTATIC PRECIPITATOR: In this we have electrodes which attract fly ash and

extract it from flue gases so that it cannot enter atmosphere.

CHIMENY:It is used to release flue gases into the atmosphere. TURBINE:Turbine is the part which revolves due to steam

pressure. It is of three types.a) High pressure turbine.b) Intermediate pressure turbine.c) Low pressure turbine.

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TURBO GENERATOR:It is the main machine which produces250 MW

electricity . CONDENSER:It condenses steam coming from low pressure turbine

(L.P.T.) to hot water. By removing air and other non-condensable gases from steam while passing through them.

COOLING WATER (C.W.) PUMP:This pump send water from cooling tower to condenser. COOLING TOWER:It is used to cool the water its height is near about 143.5

mtrs. The hot water is led to the tower top and falls down through the tower and is broken into small particles while passing over the baffing devices. Air enters the tower from the bottom and flow upwards. The air vaporizes a small percentage of water, thereby cooling water falls down into tank below the tower from where it is pumped to the condenser and cycle is repeated.

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Environmental Issues Associated With a

Thermal Power Plant

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Air Pollution :-High particulate matter emission levels due to burning of inferior grade coal which leads to generation of large quantity of flyash

Emissions of SO2, NOx & Green house gas (CO2) are also matter of concern

Water Pollution :- Mainly caused by the effluent discharge from ash ponds, condenser cooling /cooling tower, DM plant and Boiler blow down.

Noise Pollution :- High noise levels due to release of high pressure steam and running of fans and motors

Land Degradation :- About 100 million tonnes of fly ash is generated by use of coal far energy production. The disposal of such large quantity of fly

ash has occupied thousands hectares of land which includes agricultural and forest land too.

ENVIRONMENTAL ISSUES IN COAL BASED POWER GENERATION

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POLLUTION LOAD FROM COAL BASED THERMAL POWER PLANT

Pollutants Emissions (in tones/day)

CO2 424650

Particulate Matter

4374

SO2 3311

NOx 4966

Ref:-CPCB 2012

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Status of Pollution Control in Thermal Power Plants in India

Total number of power plants : 81 

Air Pollution

 ·        Power plants complying with emission : 43 standards ·        Power plants not complying with emission : 35 standards ·        Power plants closed : 03 

Water Pollution  ·        Power plants complying with ash pond : 49 Effluent standards ·        Power plants not complying with ash pond : 29 Effluent standards ·        Power plants closed : 03

Ref:-CPCB 2012

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Activities involved and their Impacts

Change in land use pattern/ Site clearing:-•Erosion•Loss of biodiversity•Loss or change of soil quality and quantity•Huge diversion and acquisition of land in case of power plant with Captive mining

Civil works:-•Dust pollution •Noise pollution

Operational Activities:-•Air pollution•Waste generation•Water consumption•Emission of mercury•Greenhouse emission

Local biodiversitySolid waste management

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Activities involved and their Impacts

Air pollution from point sources:-Particulate matter, Gaseous emission- SOx,, NOx,CO, CO2, hydrocarbon etc…

Air pollution from non-point sources:-Transport of coal, loading/unloading, coal storage, fly-ash handeling

Sources of water pollution:-Cooling tower blow down, Boiler blow down, Demineralisation (DM), plant effluent,Leachate of heavy metal (ash pond) contaminate ground water, Effluent from oil handeling and transformer areas, power house and turbine Area Effluent , Domestic waste water

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REASONS FOR NON-COMPLIANCE OF ENVIRONMENTAL STANDARDS IN THERMAL POWER PLANTS

Inconsistent supply of coal

High resistivity of coal

Inefficient operation of ESPs

Delay in supply of ESPs

Low Specific Collection Area (SCA) of ESPs

Inefficient management of ash ponds

Large quantities of ash generation

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An Indian Case Study On

Comprehensive EIA Of

THERMAL POWER PLANT at Raigarh district of Chattisgarh

by Jindal Steel and Power Ltd (JSPL)

For better understanding of EIA

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Project Proposal• JSPL is operating a open cast coal mine, along with Crushing, Screening and Washing plant

•JSPL is now proposing to set up a 2*150 MW thermal power plant which will use the middling and coal fines generated during coal washing as Raw material

•The company runs a steel plant in Raigarh and proposes to transmit the power generated by this thermal power plant to its steel plant through its own dedicated transmission network

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Salient features of the projectLocationVillage- Dongamahua, 50kms away from Raigarh

The KELO river flows at a distance of around 3.5 kms from this proposed site. There are many seasonal drains and tributeries of the Kelo, which ultemately merge into the river

FuelCoalRequires 2.47 million tonnes of coal per annum (@ 312tonnes/hr for 330 days)Middlings and coal fines will be tranported to plant site via road or conveyor beltsThe project will also require some light diesel oil (LDO)

Water Requirement7.46 MCM which will be sourced from ground water collected in the mine sump, and from bore borewell

Land useRequires 56 acres (22.7 hectares of land), Flat topography, either agricultural or wastelandHuman habitation94 inhabited revenue villages

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IMPACT ANALYSIS

→ Type biophysical, social, health or economic

→ Nature direct or indirect, cumulative, etc.

→ Magnitude or severity

high, moderate, low

→ Extent local, regional, trans-boundary or global

→ Timing immediate/long term

→ Duration temporary/permanent

→ Uncertainty low likelihood/high probability

→ Reversibility reversible/irreversible

→ Significance* unimportant/important

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TOOLS FOR IMPACT ANALYSIS

checklists

matrices

networks

overlays and geographical information systems (GIS)

expert systems

professional judgement

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IMPACT MITIGATION

to avoid, minimise or remedy adverse impacts

to ensure that residual impacts are within acceptable levels

to enhance environmental and social benefits

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FRAMEWORK FOR IMPACT MITIGATION

Common (desirable)

Rare (undesirable)

Alternative sites or technology to

eliminate habitat loss

Actions during design, construction and

operation to minimise or eliminate habitat

loss

Used as a last resort to offset habitat loss

Avoidance

Mitigation

Compensation

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REPORTING

Different name of EIA reports

Environmental Impact Assessment Report (EIA Report)

Environmental Impact Statement (EIS)

Environmental Statement (ES)

Environmental Assessment Report (EA Report)

Environmental Effects Statement (EES)

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Remediation Measures in Thermal power plant

Air pollution control:-For boiler stacks ESP/ Bag houseCoal crusher Bag filterCoal mill Bag filter

SOx control:-Use of alternative fuelLow sulphur containing fuelLime dosingHigh stack

NOx control:-Ammonia injectionLow NOx burnerFlue gas recirculation

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Remediation Measures in Thermal power plant

Fugitive Dust control:-Covered storage yard for coalClosed unloading of coal with adequate dust suction deviceClosed conveyor belt for transportation of raw

Fly ash management:-Ash disposal site should be lined to prevent metal contaminationConstruction of green barrier all around the ash pondConstruction of piezometric holesRecycling of ash pond effluents

New technologies practices:-

Water conservation techniques:-

Practices to reduce transportation impact:-

Practices for soil management:-

REFRENCES:-

1. CPCB2. An India case study on Thermal power plants3. International journal of Environmental Engineering and management4. www.envfor.nic.in5. www.harmo.org/confrences6. www.environmental-experts.com7. Dr. Amit Jain

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