Optimization Design Of Cold End System In A North Power Plant

With the national energy-saving emission reduction policies being implemented, sustainable development has become the future way of Chinese energy construction. And how the power station builders should do to improve output of power plant unit become their bounden duties. Cold end system is one of important systems in the conventional power plant, its running state directly affects the back pressure and power of unit. Thus the optimization of the cold end system to improve the cold end performance of unit is the best way to save energy, reduce emission and increase the efficiency of power plant.Through five commonly used parameters of cold end system being analyzed and calculated, the steam turbine, the condenser, the circulating cooling water and the circulating cooling water pump are discussed to achieve the optimal allocation. According to the comprehensive calculating results of the turbine output increasing under different back pressure, the condenser investment changes, the circulating water pump power changes, and other related facilities investment cost, the recovery period is economically analyzed and gained, the optimal scheme is ascertained, and therefore the largest investment income of the whole unit is ensured.In this paper, a large condensing1000MW steam turbine is taken into account, on the basis of the main steam parameters and the natural environmental parameter of reference station, the steam turbine, the condenser and the circulating cooling water are preliminary designed, by using the general incremental comprehensive economic calculation, the optimal back pressure of the power plant is in the range of0.035to0.04bar, and the following conclusions are drawn: if the cooling water temperature is low, the lower back pressure can be chosen so as to improve the turbine output. And under certain parameter, the turbine rotating speed can be reduced, the exhaust steam area of the steam turbine can be increased to reduce the residual speed loss. The design model in this paper can be used as reference for subsequent power plant design and cold end optimization under different environment, the research result has very important significance at the preliminary design and the equipment tendering stage.