600 MW直接空冷机组风机转速优化

Fan Speed Optimization for 600 MW Direct Air-Cooling Units

直接空冷机组风机转速与其排汽压力紧密相关,故直接影响机组运行经济性。因此,基于环境温度、风速及风向等影响因素,确定最佳风机转速,对实现节能降耗具有较大意义。以某600 MW直接空冷机组为例,建立风机转速优化目标函数,通过分别确定风机工作点、风机转速与排汽压力的关系及汽轮机功率背压特性,得到目标函数值,利用适当的优化算法确定最佳风机转速。结果表明:随着环境温度或风速或机组负荷的增加,排汽压力逐渐提高,进而最佳风机转速也随之增大,反之降低;当环境温度高于20℃时,对风机转速的影响较为突出;环境风向对风机转速也具有一定影响,其最佳值在x风向下最高,在主导风向下最低。

The fan speed of direct air-cooling unit related with exhaust pressure directly affects unit＇ s operation economy. Therefore, it is important to determine the optimal fan speed for energy saving, considering the influences of environmental temperature, wind velocity, wind direction and so forth. Taking a 600 MW direct air-cooling unit as example, the objective function of fan speed optimization was developed. The value of objective function was obtained through the relationship of fan＇ s working point, speed and exhaust steam pressure, as well as the back pressure characteristics of turbine, and then the optimal fan speed was determined through appropriate optimization algorithm. The results show that exhaust pressure increases with the increase of environmental temperature, wind speed or unit load, which will make the optimal fan speed increase; the contrary decreases. When environment temperature is higher than 20℃, its impact on fan speed is more significant. Wind direction also has an influence on the optimal fan speed, whose maximum value appears in the x wind direction, and minimum value appears in dominant wind direction.