600 MW机组空冷岛降背压技术方案研究

空冷机组节省水资源,但是环境温度升高后,汽轮机的排汽压力升高,增负荷受限。为解决这一问题,以600 MW直接空冷机组为研究对象,采用6种方案,对原有空冷岛,通过增加散热面积和设置尖峰冷却装置进行降背压,以实现夏季负荷的增加。通过热力性能和经济性分析,结果表明,各方案使机组背压均有降低;在运行时间相同时,方案六改造效果最好,可节标煤约11274.5 t,降背压约8.4 kPa,但静态回收投资年限长约6.7年,且增加厂区的占地面积;方案一静态回收投资年限最短,约5.8年,但仅降背压约5.2 kPa。若考虑到场地限制及环境风影响,根据改造效果和静态投资回收年限,方案二为最佳方案,即增加15个冷却单元,可节标煤约11009.9 t,降低背压约8.2 kPa,静态投资回收投资年限约5.9年。

Research on Air Cooling Island Back Pressure Reduction Technology for 600 MW Units

Air-cooled units save water resources,but after the ambient temperature rises,the exhaust pressure of the steam turbine rises,and the load increase is limited.To solve this problem,this paper takes 600 MW direct air-cooled units as the research object,and adopts six schemes to reduce the back pressure of the original air-cooled island by increasing the heat dissipation area and setting peak cooling devices,so as to increase the summer load.Through thermal performance and economic analysis,the results show that each scheme can reduce the unit's back pressure;when the running time is the same,the scheme 6 has the best transformation effect.It can save standard coal about 11274.5 t and reduce back pressure about 8.4 kPa,however,the static investment recovery period is about 6.7 years,and the plant area is increased.Scheme 1 has the shortest investment recovery period,about 5.8 years,but only reduces back pressure about 5.2 kPa.Considering the site constraints and environmental wind impacts,the scheme 2 is the best scheme,that is,adding 15 cooling units,which can save standard coal about 11009.9 t,reduce back pressure about 8.2 kPa,and the static investment recovery period is about 5.9 years.