300MW直接空冷供热机组冬季优化运行

为了保证300 MW直接空冷供热机组在冬季运行的安全防冻,提高空冷供热机组的运行经济性,分别在冬季相同电、热负荷,不同环境温度下和不同电、热负荷,相同环境温度下对某电厂2×300 MW直接空冷供热机组风机不同运行方式进行了优化试验。分析了各工况下风机群冬季运行频率、电流、耗功关系,电、热负荷与排汽背压、风机耗功关系,低背压下机组电、热负荷与排汽量、热耗的关系等。对不同负荷下机组运行的防冻回暖提出了控制机组进汽量和供热抽汽量范围、保持较多排风机投入和频率相同且低频运行、投入逆流风机回暖等建议。机组经冬季优化运行后,排汽背压下降了3 kPa,供电煤耗平均下降了3 g/kWh,年经济效益增加192.7万元。

Optimized Operation of 300 MW Direct Air-cooling Heat-supply Units in Winter

In order to explore the ways of anti-freezing and improving operation economy of the direct air-cooled heating units in winter,an operation optimization test has been performed in a home-made subcritical 2×300 MW direct air cooling heating unit.Operating frequency of draft fan groups in relation to electric current and power consumption in winter under various operation conditions,electric heating load in relation to the exhaust steam backpressure and power consumption of the fans as well as the unit electric heating load in relation to exhaust and heat loss under low back pressure have been analyzed.Suggestions on anti-freezing of direct air-cooling system under different loads were put forword：to control the turbine steam inlet and heat supply extraction;to put fans on multi-rows in operation under low frequency;to control warm return of the counter-flow fans.After winter operation optimization of the unit,not only anti-freezing problem can be solved,but also the exhaust steam pressure is reduced by 3 kPa,coal consumption decreased by 3 g/kWh,with yearly increase of 1 927 000 yuan of direct economic benefit.