摘要
针对330MW亚临界直接空冷燃煤火力发电机组,建立了实时运行工况的热耗率和冷端损失的计算模型,定量分析了负荷、环境温度和背压等因素对机组效率、乏汽湿度和凝汽器端差的影响规律。结果表明,实时热耗率模型能较好地适用于空冷机组的性能分析。冷端损失能量占总输入能量的52.8%,占总损耗能量的87.2%。从长期稳定运行的趋势来看,在滑压变负荷运行模式下低压缸排汽湿度随主蒸汽压力增加而单调增大。在某些工况下,乏汽湿度大于15%,可能会引起叶片水蚀,降低末级叶片寿命。由于直接空冷凝汽器表面换热系数随负荷波动较小,直接空冷凝汽器的传热端差和平均换热温差均随负荷增加而单调增大。研究成果可为空冷机组的热耗率实时定量分析、冷端运行优化和乏汽湿度控制提供参考。
To calculate the real-time heat rate and energy loss in cold ena, a moue, ~u~ o direct air-cooling units was established to quantitatively study the effects o~ the unit load, environmental temperature and back-pressure on the unit efficiency, exhaust steam humidity as well as terminal temperature difference of condensers. The results show that the real-time turbine heat rate model can be well applied to analysis on the performance of the direct air-cooling genera^ting units. The ratio of energy loss in cold end is 52. 80./00 of total input energy and 87. 2~~ o{ total energy loss respectively. The exhaust steam humidity increases with the increase of main steam pressure under sliding pressure and variable load conditions for the long-term stable operation. In some cases, since the exhaust steam humidity is larger than 15~/~0, the service life of the last stage blades may be reduced hecause of the water erosion. The overall heat transfer coefficient of the direct air-cooling condenser hardly varies with the unit load, thus, both the terminal temperature difference of the condenser and the average heat transfer temperature difference increase with the increase of unit load in direct air-cooling generating units. The research results can provide reference for the real-time heat rate calculation, cold end optimization as well as the control of the exhaust steam humidity.
出处
《热力透平》
2017年第4期274-278,共5页
Thermal Turbine
关键词
燃煤火力发电机组
直接空冷凝汽器
热耗率
供电煤耗
乏汽湿度
coal-fired generating unit
direct air-cooling condenser
heat rate
power supply coal consumption
exhaust steam humidity
