面向火电运行灵活性的钢球磨煤机制粉系统控制优化研究

Study on control optimization of steel-ball mill coal pulverization system for flexible operation of thermal power plant

针对双进双出钢球磨煤机制粉系统变出力过程风粉温度波动幅度大、瞬时磨煤出力偏差大等问题,提出考虑热一次风风温前馈和变出力过程料位差压设定值优化的控制策略。以BBD4360型钢球磨煤机为对象开展机理建模和瞬态扰动试验研究,建立并验证钢球磨煤机内料位差压、出口风粉温度等关键参数计算模型。基于磨煤机动态模型研究获得原有及优化后的控制策略对磨煤机出口风粉温度、磨煤出力和制粉单耗的影响规律。研究结果表明:在制粉系统变出力过程中,优化后的控制策略可降低磨煤机出口风粉温度偏差2℃以上,制粉系统磨煤出力累积偏差降低50%以上,制粉单耗降低5%以上,综合提升了制粉系统的关键参数控制效果。钢球磨煤机制粉系统优化控制策略有利于缓解机组调峰过程中由于燃料量供给偏差引起的气温、气压偏差大等问题,保障了燃煤发电机组的运行灵活性和高效性。

In order to solve the problems of the large fluctuation of the outlet air-powder temperature and the considerable deviation of the instantaneous coal mill output during the process of load cycling of the double-inlet and double-outlet steel ball mill system,several control strategies of considering the feedforward of hot primary air temperature and the optimization of coal level differential pressure setting value were proposed.The mechanism modeling and transient disturbance experiment research were carried out for one BBD4360 steel ball mill,and the models of the critical parameters,such as the coal level differential pressure and the outlet air-powder temperature,were established and verified.Based on the study of the dynamic model of the coal mill,the influence of the original and the optimized control strategies on the outlet air-powder temperature,the output of the coal mill,and the power consumption of the coal pulverizing system were obtained.The results show that the proposed control strategy can reduce the temperature deviation of the pulverized coal at the outlet by more than 2℃,reduce the cumulative deviation of the pulverized coal output of the pulverizing system by more than 50%,and reduce the average energy consumption of the pulverizing system by more than 5%,comprehensively improving the control effect of the critical parameters of the pulverizing system.The optimal control strategy of the ball mill pulverized system can effectively reduce the steam temperature and pressure deviations caused by the fuel supply during the peak shaving process and ensure the operational flexibility and efficiency of coal-fired generating units.