At present

larger deviation exists between burnt and designed coal sorts in many thermal power plants of our country

the increase of ash content in coal and the decrease of calorific value of coal lead to high temperature of superheater and reheater tubes in boiler operation

resulting in augmentation of desuperheating water

in elevation of exhausted flue gas temperature

and in reduction of boiler efficiency.The parameters and coal quality in operation of boiler equipped for one 600 MW unit have been analysed

finding out the causes leading to augmentation of desuperheating water for the said boiler.Through optimization of retrofit scheme for heating surface in the boiler

the boiler efficiency has been increased by 1.52%

reducing coal consumption 13.80 g/(kW·h);the desuperheating water of reheater being decreased 64.65 t/h

reducing the coal consumption 10.21 g/(kW·h).