一次、二次再热机组汽轮机高低位布置方案热经济性分析

Thermal-economic analysis for scheme of steam turbine generator placement in high and low platform separately

为了分析汽轮机高低位布置的热经济性,基于流体力学理论,采用国际通用的前苏联标准、美国标准、德国标准计算了采用高低位布置方案前后热力系统的阻力变化,并基于EBSILON?热力分析软件建立了国内典型1 000 MW一次再热和二次再热机组详细的热力系统模型,对比了常规布置和高低位布置方案的热经济性。结果表明:采用高低位布置后,主、再热蒸汽管道阻力下降引起系统热耗率降低的数量级一致;一次再热机组采用高低位布置后由于系统阻力下降,发电煤耗率降低0.5 g/(kW·h)左右;二次再热机组采用高低位布置后,系统发电煤耗率降低1 g/(kW·h)左右。

In order to analyze thermal economy of thermal system with steam turbine generator placement in high and low platform separately （new replacement scheme）, the resistance change of the thermal system before and after the new scheme is employed was calculated based on fluid mechanics, and the detailed thermodynamic model for domestic typical 1 000 MW unit with single- and double-reheat cycle was established, on the basis of the EBSILON~ software. Moreover, the thermal efficiency of the thermal system using regular scheme and the new scheme was compared. The result shows that, in the new scheme, the heat rate drops caused by resistance drop in the main steam pipe and reheat steam pipe are in the same order of magnitude. For reheat units, because the system resistance decreases after the new replacement scheme is used, the coal consumption rate of power generation reduces by 0.5 g/（kW·h）. For double-reheat units, the coal consumption rate of power generation reduces by 1 g/（kW.h）, which is as twice as that of the reheat-units.