机组冷态启动中几种投运方案经济性分析

Economic analysis on several operation schemes for steam-driven feedwater pump group during unit cold starting

以华能丹东电厂亚临界350 MW机组为例,针对前置泵与小汽轮机同轴驱动的汽动给水泵(汽泵)组在机组冷态启动中的投运方式进行分析,并对3种投运方案的经济性进行了计算比较。结果表明:机组冷态启机初期锅炉上水、锅炉冲洗及提高锅炉温度至汽轮机转速达到2900r/min暖机期间均采用电动给水泵(电泵),之后投入第1台汽泵至机组负荷达到30%的方案3经济性和安全性最佳。因此,并非所有机组的冷态启动均适用汽泵启动,而应综合考虑各机组的实际情况,提出合理的启动方案。

By taking a subcritical 350 MW unit in Huaneng Dandong Power Plant as an example,the opera-tion schemes of the steam-driven feedwater pump group of which the booster pump and small steam turbine are driven coaxially were investigated.Moreover,the calculated economy of three schemes was compared. The results show that,the Scheme III has the optimum economy and safety,in which the motor-driven feedwater pumps were adopted during water feeding,boiler washing and furnace temperature enhancing un-til the steam turbine speed increases to 2 900 r/min in the initial stage of unit cold state startup,then the first steam-driven feedwater pump was put into service when the unit load reached 30%.Therefore,not all units are fitted for using steam-driven turbine to accomplish cold state startup.The reasonable startup schemes should be proposed by considering the actual situation of each unit comprehensively.