Directing against the problems of low thermal efficiency of CFB boilers for unit no.2 in Yongji Power Plant

test and study have been carried out.It is believed from analysis that the main causes leading to low thermal efficiency of CFB boilers are as follows:low calorific value of the fuel coal

small oxygen concentration at inlet of the air preheater

low efficiency of the separator

fine coal particle resulting in high carbon content of fly ash.For these

through optimizing selection of primary and secondary air amount

as well as installing sieving facility in front of the coal pulverizer to reduce the fine coal particles

making the carbon conten in fly ash decreased from original 14.35%

13.92%

and 12.47% to 10.34%

9.93%

and 8.90% respectively

the thermal efficiency of boilers being enhanced from original 87.374%

87.767%

and 87.916% to 89.290%

89.77%

and 89.848% respectively

having remarkable effectiveness.