机跟炉协调控制在300MW CFB锅炉煤质大幅波动时的应用

Application of turbine following boiler coordinated control in 300 MW CFB boiler against the great change in coal quality

由于循环流化床(CFB)锅炉燃料颗粒大,燃烧过程滞后时间较长,在煤质大幅波动时,采用炉跟机协调控制的控制品质较差。在白马示范电站300MW CFB锅炉上,尝试采用以机跟炉为主的协调控制方案,并根据煤质频繁大幅波动的特点,在CCS控制回路中设计了煤质修正计算逻辑和氧量校正逻辑。调试中根据实际情况,在煤质修正逻辑的蒸汽吸热量计算中增加了汽包压力的微分信号,并将氧量校正逻辑中氧量控制的输出只作用于煤量。实践证明:投入机跟炉协调控制后,主汽压力稳定,机组负荷基本能控制在上网负荷的±2%以内,协调控制系统能长期稳定投入运行。

In view of large grain size of fuels and long lagging of combustion in CFB boiler, the control quality of turbine following boiler CCS became deteriorated in case of great change in coal quality. The turbine following coordinated control mode was utilized on 300 MW CFB boiler in Baima Demonstration Power Station. Considering the frequent fluctuation in coal quality, the coal quality calculation logic and oxygen content correction logic were designed in CCS control loop. Base on the practical conditions in commissioning, the differential signal of drum pressure was added in the calculation of steam heat absorption to optimize the coal quality correction logic; in addition, the output of O2 controller was only performed on the coal to improve the oxygen content correction logic. The practice shows that the main steam pressure is stable, the load range can be limited within ±2% of the grid load, and the CCS can be put into long stable operation in the case of turbine following boiler coordinated control.