直接空冷机组提高真空度的分析与改进

Analysis and improvement for vacuum system of direct air cooling power generation unit

针对某350 MW直接空冷机组在夏季高温工况出现凝汽器真空度偏低问题进行了分析,认为主要原因是凝汽器内温度较高的气汽混合物抽吸进入水环式真空泵后,造成工作液温度升高,真空泵汽蚀运行造成抽真空能力下降;采取辅助冷凝系统以及罗茨–水环真空泵组合改造后,进行了春季,夏季工况比对测试,结果表明凝汽器真空度可以提升约0.4~1 kPa,真空泵工作电流减少约50%,改造项目具有较好的节能经济效益和推广价值。

Low vacuum degree in the condenser of 350 MW power generation unit with direct air-cooling system isoccurred under high temperature condition in summer.Analysis shows that the main reason is that the temperature ofworking liquid increases after the high temperature air-steam mixture extracted into the water ring vacuum pump,andthus the performance of vacuum pump degrades.The auxiliary condensing system of extracted pipeline is added and thecombined vacuum device of roots-water ring vacuum pump is used.The comparison test results show that the vacuumdegree of the unit can be increased by about 0.4~1 kPa and the vacuum pump working current can be reduced byabout 50%,which has good economic benefits and popularization value.