背压对抽凝机组热耗率的修正计算

Correction Calculation of Heat Rate of Extraction Condensing Steam Turbine by Modified Back Pressure

近年来,随着环保和压减燃煤压力日趋增大,火电的开机占比和利用小时数逐年下降,导致汽轮机组长时间处于偏离各设计参数状态下低负荷运行的现状。汽轮机实际运行过程中的负荷、循环水参数等都是不断变化的,这些变化会对背压产生影响,而背压又是影响热耗率的重要参数之一。针对背压变化对抽汽凝汽式汽轮机热耗率不能直接进行修正计算的问题,提出一种将抽凝机组分为供热循环和凝汽循环的修正计算方法。该方法可较为简便地计算出背压对抽汽凝汽式汽轮机热耗率的影响,从而为抽汽凝汽式汽轮机经济运行提供指导。

In recent years,with the increasing of environmental protection and pressure reduction of coal-fired coal,the proportion of start-up and utilization hours of thermal power decreased year by year,which led to the situation that the steam turbine was in low load operation state deviating from the design parameters for a long time.During the actual operation of steam turbine,the load and circulating water parameters are constantly changing,which will affect the back pressure,which is one of the important parameters affecting the heat rate.In view of the problem that the heat rate of extraction condensing steam turbine can not be directly calculated by the change of back pressure,a modified calculation method was proposed to divide the extraction condensing unit into heating cycle and condensing cycle respectively.This method can calculate the influence of back pressure on the heat rate of extraction condensing steam turbine,and provide guidance for the economic operation of extraction condensing steam turbine.