以某燃煤电厂2×300MW机组循环水系统为研究对象，充分考虑外界环境因素，基于循环水泵运行优化理论建立了冷却塔、凝汽器与汽轮机低压缸耦合的冷端优化数学模型。基于麦克尔焓差理论建立冷却塔热力计算模型并给出冷却塔出塔水温的计算方法，研究了环境温度、相对湿度、循环水量对冷却塔出塔水温的影响。研究了机组背压、循环水量与排汽流量对凝汽器真空的影响。绘制全工况下循环水泵运行方式间的等效益曲面，确定了不同的机组负荷、环境温度及相对湿度下循环水泵最佳运行方式。对比传统循环水泵优化方式，可知新型等效益曲面方法具有一定的合理性。对火电机组实际运行中循环水系统优化有一定的指导意义。

Taking the circulating water system of a 2×300MW unit in a coal - fired power plant as the research object and considering the external environment factors, a coupled mathematical model of cooling tower, condenser and low pressure steam turbine cylinder was proposed. Based on the Michael enthalpy difference theory, the thermodynamic calculation model of the cooling tower was put forward and the calculation method of the cooling tower outlet water temperature was given. The influence of the ambient temperature, relative humidity and circulating water flow on the outlet water temperature of cooling tower was studied. The effects of back pressure, circulating water flow and exhaust steam flow on condenser vacuum were researched. The equal efficiency curved surface of neighbor pattern in all operating conditions was drew and the best operation mode of circulating water pumps was determined according to unit load, environmental temperature and relative humidity. Compared with the conventional approach of operation optimization for circulating water system，the novel way of equal efficiency curved surface had certain rationality, which is of great significance for operation optimization of circulating water system in power plant.

TM621