To solve the problems occurred during the operation

such as low ascending and descending rate of unit load

unstable air and flue system etc

optimization of control strategy for unit coordination as well as air and flue system was conducted

based on the analysis of control strategy for a 300 MW unit with CFB.After the improvement

the ascending and descending rate of unit load significantly increased;when the load rose from 200 MW to 250 MW at rate of 4.5 MW/min

and dropped from 300 MW to 250 MW at the same rate

the deviation of main steam pressures were below 0.6 MPa

and the bed temperatures were controlled within 850~900 ℃.Therefore

all the main parameters were controlled within normal range.