In China

several problems occur in large number of 300 MW unit CFB boilers

such as large bed temperature deviations

existence of local high temperature points and relatively high original emission concentration of SO2 and NOx

which brings difficulties in energy saving

cost reducing and ultra-low emission of the CFB boilers.Analysis shows that

the deviations of separator flow and efficiency result in deviations between the circulation volume and the material concentration in the circulation loop

thus bring the temperature deviation at both sides and middle part of the bed.The temperature deviation can be avoided by retrofitting the separator inlet gas flue and cyclone vortex

which would contribute to a more even coal supply.After transformation

the average bed temperature decreased by more than 35℃

and the consumptions of the desulfurizer and denitration urea are reduced by 40% and 20%

respectively.