Performance enhancement in coal fired thermal power plants. Part IV: overall system

This paper provides an analysis of the overall performance of 22 coal-fired power plants. The net overall efficiency is in the range 19·23–30·69%. The effects of ash in coal, contaminants in feed water, leakage, incondensables, etc., have been quantified. Ways of minimizing secondary oil consumption have been provided. The techniques for performance improvement, low cost as well as capital intensive, have been described. The role of overhauling the plant and associated opportunities for performance improvement are also discussed.

It is concluded that achieving a high annual plant load factor (PLF) will bring about all round improvement in the unit performance. Unless the pressing problems of high ash in coal, inadequate contaminant control and leakage/ingress are solved, mere repowering by equipment of higher efficiency may not yield the desired results. Design margins of 10–20% are essential for both repowered and new units. In the long term, it is economical to de-commission all units below 210 MW and only three sizes need be retained: 210, 500 and 1000 MW. Automation of the DM water plant provides maximum economic advantage. Considerable opportunity exists for energy conservation through introduction of information technology and variable frequency drives in all units. Copyright © 1999 John Wiley & Sons, Ltd.