700MW级多轴燃气-蒸汽联合循环机组调峰和启动特性

Start-up and peaking characteristics of a 700 MW-class combined gas-steam cycle unit with multi-shaft arrangement

针对华北电网负荷峰谷差逐年增长的现状,介绍了一套可参与调峰运行和黑启动的700MW级多轴布置燃气-蒸汽联合循环机组的热力系统,给出了机组的效率、启停时间、负荷变化率等重要参数。相比燃煤机组,该联合循环机组具有效率高、启停快、运行灵活等优点,适合作为华北电网的调峰运行机组。针对启停快、可靠性高的特点,论证了其可作为华北电网黑启动电源的可行性和优势。分析了余热锅炉烟气温度和减温水量随燃机负荷变化的特性,并重点讨论了调峰运行中防止蒸汽超温和低温腐蚀的措施。

In view of the increasing tendency of peak-valley difference in North China Grid, a thermal system is introduced for a 700 MW- class combined gas-steam cycle unit with multi-shaft arrangement, which could be helpful for the peaking and black-start of grid. Compared with coal-fired unit, the combined cycle unit has the advantages of higher efficiency, faster start-up and more flexible loading change, which can meet the requirement of peaking better. And its reliability shows the feasibility and advantage to be a backup power source for black-start of North China Grid. The efficiency, start-up time and load change rate of the unit are summarized, and the gas characteristics are described by providing the relationship curves between gas turbine load and flue gas temperature and flow rate. The measures are discussed to prevent the over-temperature of steams and low-temperature corrosion during peaking running.