Selection of Steam Power Station
A steam power plant should have low cost & high thermal efficiency. If the steam power plant is coal based. It should be able to burn inferior quality of coals with high ash content.
Factor of selecting site for steam power plants:
Availability of raw materials: Steam power plant using coal or oil as fuel require very large amount of fuel per annum.
Nature of land and its cost: The selected site should have high bearing capacity of at least 10 N/sq mm to with stand dead load of the plant. It would reduce the cost of the foundation of the plant.
Availability of water: Steam power plant use water as working fluid throughout the year, which is repeatedly evaporated and condensed. It also need about 2% of steam generated as make up water due to its loss.
Load center: The location of plant at center of loads reduces the cost of transmission lines and the losses occurring in it.
Transport facilities
Availability of labour
Ash handling facilities
Future expansion
Pollution
Away from Air fields.
1. Nearness to the Load Centre:
The power plant should be as near as possible to the centre of the load so that the transmission cost and losses are minimum. This factor is most important when dc supply system is adopted. However, in case of ac supply system when transformation of energy from lower voltage to higher voltage and vice versa is possible, power plant can be erected at places other than that of centre of load provided other conditions are favourable.
2. Supply of Water:
Large quantity of water is required in a steam power plant.
It is required:
(i) To raise the steam in boilers.
(ii) For cooling purposes such as in condensers.
(iii) As a carrying medium such as disposal of ash and
(iv) For drinking purposes.
3. Availability of Coal:
A huge amount of coal is required for raising the steam (20,000 tonnes per day for a 2,000 MW station). Since the Government policy is to use only low grade coal with 30 to 40% ash content for power generation purposes, the steam power plant should be located near the coal mines to avoid the transport of coal and ash.
4. Land Requirement
The land is required not only for setting up the plant but for other purposes also such as staff colony, coal storage, ash disposal etc. For a 2,000 MW plant, the land requirement may be of the order of 200-250 acres. As the cost of the land adds up to the final cost of the plant, it should be available at a reasonable price. Land should be also available for future extension.
5. Type of Land:
Land should be of good bearing capacity since it is to withstand not only the dead load of the plant but also the forces transmitted to the foundations due to the operation of the plant and this total load
6. Transportation Facilities:
The facilities must be available for transportation of heavy equipment and fuels e.g., near railway station.
7.Labour Supplies:
Skilled and unskilled labourers should be available at reasonable rates near the site of the plant.
8.Ash Disposal:
Ash is the main waste product of the steam power plant and with low grade coal, it may be 3.5 tonnes per day, hence some suitable means for disposal of ash should be thought of. It may be purchased by building contractors, or it can be used for brick making near the plant site. If the site is near the coal mine, it can be dumped into the disused mines. In case of site located near a river, sea or lake, ash can be dumped into it. If the waste land is available near the site, then an area of 40 hectares excavated to a depth of 6.5 metres will be required per year for a 2,000 MW plant.
9. Distance from Populated Area:
Since most of the modern generating stations employ pulverised fuel- residues and fumes from them are quite unhealthy, therefore the site for the power station should be away from the populated area.
Comments
Post a Comment