超临界600MW机组直流锅炉循环泵式起动探讨

AN APPROACH TO START-UP MODE WITH CIRCULATORY PUMP FOR ONCE-THROUGH BOILER OF SUPERCRITICAL 600MW UNIT

对比循环泵式起动与直排式起动的特点,包括冲洗流量、起动初期的工质及热量损失、起动期间贮水箱水位控制策略以及锅炉转直流期间的特性得出,超临界锅炉采用循环泵式起动系统提高了水冷壁在低负荷下运行的可靠性和经济性,降低了机组起动阶段工质和热量的损失,缩短了起动时间。评价采用直排式起动的安全性得出,循环泵故障时,采用直排式起动完全可以满足机组的安全起、停要求。

Through comparison of features in start- up with circulatory pump and start- up with straight discharge, including flow rate of the flushing water, working medium and heat loss in the initial phase of start- up, control strategy of water - level in the water storage tank during the time of start- up,and boiler performance during the time of turning it into once- through mode,it has been obtained that the adoption of start - up mode with circulatory pump for supercritical boiler can enhance reliability and economic efficiency of the water wall during operation under low load, reducing work medium and heat loss of the unit in start - up phase, and shortening the time of start - up. From evalua- tion of safety in start - up mode with straight discharge, it is obtained that the adoption of start - up mode with straight discharge can fully satisfy the requirements of safe start - up and shutdown of the unit after failure of the circulatory pump.