350MW超临界CFB机组协调控制系统分析

Analysis on the Coordinated Control System of a 350 MW Supercritical CFB Boiler Unit

结合某350 MW超临界循环流化床(CFB)机组协调控制系统,依靠锅炉主控前馈量的合理设置、煤水的精确耦合、汽轮机调节阀负荷响应能力的充分发挥等,克服超临界CFB燃烧响应慢、热惯性大等带来的控制困难,成功实现额定负荷速率(4.5 MW/min)协调变负荷;提出煤质校正确定基准煤量,煤焓回路确定基准水量,主要控制回路的耦合要点,以及针对超临界CFB机组多发的超压、超温问题的逻辑优化等,为同类型机组协调控制提供参考。

To overcome the control difficulties caused by slow combustion response and high thermal inertial of the coordinated control system in a 350 MW supercritical circulating fluidized bed(CFB) boiler unit, the main control feedforward amount of boiler was reasonably set up, the coal and water flow were precisely coupled and the responsiveness of steam turbine regulating valve was adequately excavated, thus to successfully achieve the purpose of coordinated load variation at 4.5 MW/min. Meanwhile, following suggestions were proposed for the control system, such as to determine the reference coal flow based on coal quality correction, determine the reference water flow based on coal-enthalpy loop analysis, propose the key coupling points for the main control circuit, and to perform logical optimization to handle the overtemperature and overpressure problems occurring in the supercritical CFB boiler unit, which may serve as a reference for the coordinated control system of similar units.