循环流化床锅炉控制系统优化

Optimization of Control System for Circulating Fluidized Bed Boilers

为解决某厂2台310 t/h循环流化床锅炉控制系统一直无法投入自动的问题,结合该厂蒸汽负荷频繁波动的运行特点,在确定燃料、一次风、二次风静态关系的基础上,对循环流化床锅炉进行了蒸汽流量、燃料、一次风、二次风的扰动试验.通过分析得到母管压力、床温等参数的动态响应特性,确定了压力控制燃料、氧量修正控制二次风、床温修正一次和二次风配比的控制方案,并设计了多输出控制系统的自动平衡回路.采用新的控制策略后,无论是在外负荷扰动还是在锅炉燃料扰动下,极大程度上保证了系统的稳定性和可靠性.

To solve the problem that the control system for a 2×310 t/h circulating fluidized bed（CFB） isn＇t able to run in auto mode under frequent fluctuation of load,different disturbance tests have been carried out based on determined static relations among flow rates of fuel,primary air and secondary air.By analyzing the dynamic response of the main pipe pressure and bed temperature,some improved control strategies on fuel and air flow are put forward,in which the fuel is controlled by main steam pipe pressure,the secondary air flow is corrected by oxygen content and the ratio of primary to secondary air flow is revised by bed temperature.At the same time,multi-output self-balance control loops are designed.The application of such optimized strategies has made significant effect on the system＇s stability and reliability under disturbance of load and fuel flow.