The flame image of combustion in a boiler for 300 MW unit has been acquired through three dimentional temperature field monitoring system

and the radiant energy signal of combustion in the furnace being obtained from calculation

and the absorbed heat in different stages of process in the boiler being calculated on the basis of boiler operation parameters.The calculation shows that the radiant energy signal and the absorbed heat in different stages of process in the boiler all to be linear variation in the range of load 200~300 MW

not including the air preheater.After introducing differential signal of radiant energy into desuperheating system of the superheater

the maximal deviation of superheated steam temperature is3℃

abtaining good effectiveness in practical control.