大型直接空冷机组冷端性能优化研究

Study on Cold-end Performance Optimization of Large Direct Air Cooling Unit

直接空冷机组具有优良的防冻性能,但由于真空系统容积大,严密性指标对其空冷防冻性能影响很大。某600 MW直接空冷两缸两排汽机组由于低压缸刚度偏低,低背压运行时易引起低压缸变形造成动静碰磨振动,通过低压缸通流间隙优化、抽真空系统优化、运行方式调整等手段,实现了满足空冷防冻前提下的排汽压力优化,提高了机组低环境温度下的运行经济性,为同类型机组进行相关冷端性能优化提供了参考。

Direct air cooling units have excellent anti-freezing performance,but due to the large volume of vacuum system,the tightness index has a great impact on the anti-freezing performance of air cooling.Due to low stiffness of low-pressure cylindcr,a 600 MW two-cylinder direct air-cooling unit easily suffers low-pressure cylinder deformation when the unit runs under low back pressure,which even led to gouging abrasion and vibration.Through optimazation on flow gap,pumped vacuum system and operation mode adjustment,exhaust pressure optimization is carried out under the premise of air cooling and anti-freezing to improve the unit's operating economy at low temperature.It provides references for cold end performance optimization of the same type of units.