On the basis of boiler exergy balance mathematical model

the exergy efficiency and each exergy loss of large-scale circulating fluidized bed(CFB)boilers was analyzed.The results show that

the total exergy loss of combustion and heat transfer of the CFB boiler was over 45% of the fuel chemical exergy

which is the main exergy loss of the CFB boiler.Increasing the power unit capacity and steam parameters can increase the average heat absorption temperature of the water in furnace

thus to reduce the heat transfer exergy loss of the boiler effectively.The exhaust exergy loss rate was about 1%

which is greatly smaller than that of the exhaust heat loss rate

but there's still potential to be tapped.For CFB boilers

the exergy loss rate during combustible gas incomplete combustion and heat transfer can be ignored.The unburned carbon exergy loss

which is the chemical exergy of the unburned carbon

should be paid more attention to be reduced due to its high quality.The CFB boiler slag has a high proportion of coal ash

so reducing the slag physical exergy loss has great significance to improving the CFB boiler efficiency.