双压凝汽器最佳背压确定方法的研究

摘要

Recently , the impact of the backpressure changing to the electric power of the turbine generator is still not calculated in common method .This paper confirm the best backpressure after getting the best circulation of water by taking theoretical derivation based on the traditional definitions of the best backpressure . As the circulating-water is the independent variable,there are two factors impact the definition of the best backpressures as follows ,the increase of the generator power and the increase of circulating water-pump power consumption , which both are the function on the independent variables of the circulating cooling water .The analysis result indicates that: the dual-pressure condenser cooling effect is better than single-pressure condenser under the same amount of cooling water,and its best backpressure and average end temperature both are lower than the single-pressure condenser;the best circulating water is direct proportion to the total emissions of the steam turbine or inversely proportion to the circulating pump power consumption .%目前，背压的变化对汽轮发电机组电功率的影响还没有一种通用的计算方法。在最佳背压传统定义基础上，进行理论推导得出最佳循环水量，进而确定最佳背压。假设循环水量作为自变量时，这时影响最佳背压确定的有关因素有两个：发电机功率的增加量和循环水泵耗电功率的增量，并且它们都是以循环冷却水流量为自变量的函数。通过理论分析表明：在相同的冷却水量下双压凝汽器的冷却效果好于单压凝汽器；双压凝汽器高低压侧的最佳背压也都低于单压凝汽器的最佳背压；双压凝汽器平均端差小于单压凝汽器的端差；最佳循环水量和汽轮机的总排汽量成正比例关系或者和循环水泵电机功率成反比例关系。