蒸发冷却技术在600MW机组直接空冷系统上的应用

Application of evaporative condensing technique on condenser of a direct air-cooling 600MW unit

针对直接空冷机组在夏季背压偏高、出力受限的问题,提出采用蒸发冷却技术分流部分汽轮机排汽,降低空冷凝汽器热负荷,达到降低机组背压、提高出力的目的。以某600MW机组直接空冷系统为技术改造依托,进行蒸发冷却技术分流部分汽轮机排汽后的应用特性研究,分析了改造效果随分流量、机组负荷、环境温度的变化规律。结果表明:随着分流进入空冷凝汽器蒸汽流量比率的增大,机组运行背压下降幅度增大;随着机组负荷增大,运行背压下降幅度增大;随着环境温度升高,运行背压下降幅度呈指数关系增大;直接空冷机组处于高温高负荷运行时,蒸发式凝汽器系统的性能优势得以充分发挥。

In summer,the direct air cooling units will suffer high back pressure and its output power will be insufficient.Against this problem,the evaporative condensing technique was proposed to diverge part of the turbine exhaust steam and reduce the heat load of air cooling island,thus the unit operating back pressure can be decreased.Taking a direct air cooling 600 MW unit as the example,the application performance of evaporative condensing technique was carried out,and the change laws of application effect with such parameters as the distributing ratio of turbine exhaust,the unit load and the ambient air temperature was obtained.The results show that,the decrease of operating back pressure increased with the above parameters.The performance advantages of the evaporative condenser system will be fully played when the direct aircooling unit operates with higher load at higher air temperature.