Types of Cycle

Open Cycle system Close Cycle System

Use of Open Cycle System has been prohibited due to more efficiency of closed cycle system than open cycle system and because of economical reasons.

Thermal Power Plant: Largest Emitter of Mercury

  • • Typical power plant emits 90 % of its mercury into the air and 10 percent on land.
  • • On an average 65 tonnes of mercury released in the atmosphere by Indian thermal power plant.
  • Sameer Kumar et al 5 70

Air Pollution due to Thermal Power Plants

Air Pollution from point source:

Particulates matter, Gaseous emission - Sulphur dioxide, oxides of nitrogen, carbon monoxide, carbon dioxide, Hydrocarbon.

Air Pollution from non-point source:

• Transportation of coal, Loadmg/unloading of fuel, Coal storage yard, Fly ash handling and Transportation, Coal storage yard.

Thermal Power Plant: Potential Source of Water Pollution

  • 1. Sources of water pollution
  • • Cooling Tower Blow Down, Boiler Blow Down, Demineralization (DM) Plant Effluent, Coal Handling Plant Dust Suppression, Ash handling (Leachate of heavy metal (ash pond) contaminate groundwater), Effluent from oil handling and transformer areas, Power House and Turbine Area Effluent,Domestic waste water.

Remediation Measures in thermal power plant

  • 2. Air pollution control - Point source
  • • For boiler stacks - ESP/Bag house.
  • • Coal crusher - Bag filter
  • • Coal mill - Bag filter
  • 3. Fugitive Dust Control
  • • Covered storage yard for coal
  • • Closed unloading of coal with adequate dust suction device
  • • Closed conveyor belt for transportation of raw Material with bag filter at every transfer points.
  • 4. Fly Ash Management
  • • Ash disposal site shall be lined to prevent metal contamination.

SOx control technology NOx control technology

  • • Use of alternative fuel
  • • Use of low sulphur containing fuel
  • • Lime dosing
  • • High stack
  • • NH3 injection
  • • Use of low NOx burner
  • • Flue gas recirculation.

Environment Impact Assessment of Thermal Power Plant for Sustainable 571

  • • Construction of green barrier all around the ash pond.
  • • Pizometric hole shall be constructed upside and downside of the ash pond.
  • • Recycling of ash pond effluents.
  • • Switching from medium concentration slimy disposal system (MCSD) with ash concentration in sluny 40-45% to high concentration sluny disposal systems (HCSD) with ash concentration in sluny 65-72%

New Technological Practices

  • 5. Super Critical Technology
  • • Larger unit size (more than 500 MW) Higher thermal efficiency (of 5% and above).
  • • Low gaseous and soot emissions.
  • 6. Fluidised Bed Combustion (CFBC/PFBC).
  • • Can bum wide range of coals and other fuels such as pet coke, lignite etc.
  • • Higher thermal efficiency (>40%).

Water Conservation Techniques

Big power plant - Closed loop instead of open loop, Small power plant - Air cooling instead of water cooling, Recycle and reuse of process and effluent water, Zero discharge in case of small plant, Demineralised backwash water shall be treated with RO and reuse in process, Collection of rain water which can be used for many purposes

Practices to Reduce Transportation Impact

Encourage bulk transportation by train, Only pollution certified vehicles should be engaged in transportation, Appropriate infrastructure for vehicles such as concrete or pitched road, Separate approach road for transportation of raw materials such as coal, diesel, caustic etc.

Practices for Soil Management

Provision for topsoil storage and reuse, Separate stacking of topsoil with adequate collection rain all around, Topsoil storage heap should be covered with grasses and bushes to avoid erosion, Removing vegetative cover only from the specific site on which construction has to take place.

Practices for Reducing Noise Pollution

  • • Design of equipments, Acoustic enclosures/barrier shields Construction of sound barrier in the form structure, Personal protective equipment i.e. ear plug and ear muffs ,More than 33% of total area under green cover Recommendation of dust scavenging plant (reduce 5 to 6 dB noise).
  • • Azardirachta indica (Neem), Polyalthia longifolia (Ashoka), Calhstemon citrinus (Bottle Brush), Tennanilia catappal (Jangal Badam), Tenninalia aijuna (Arjun), Melia azedarch (Melia), Phoenix dactylifera (Khjoor).

Conclusion

On studying the whole thermal power plant we have come to a curb that though thermal power plant generates electricity but it is troublesome for the environment so we have to deal it with the technique mentioned in our research for reducing its consequences. 25% by 31st August, 2004 50% by 31st August, 2005 75% by 31st August, 2006 100% by 31st August, 2007 in respect of construction of buildings within a radius of fifty kilometers from coal or lignite based thermal power plant the following minimum percentage of use of bricks, blocks and tiles shall apply:

 
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