空冷火电机组相邻空冷岛连通设计与冷端优化

Connection design of adjacent air-cooling condensers and cold end optimization of generating units

针对330 MW亚临界直接空冷燃煤火力发电机组,建立实时运行工况的供电煤耗、汽轮机理想内功率和凝汽器端差的变背压计算模型,定量分析相邻两台空冷凝汽器连通设计对机组效率的影响规律,优化机组背压。结果表明,本研究提出的变背压模型能较好地用于预测机组整体效率和综合供电煤耗的变化。随空冷岛散热面积均匀增加,背压降低、机组出力增加、综合供电煤耗降低的边际效应逐渐变弱。综合考虑投资成本、收益和设备可靠性,将相邻两台机组空冷凝汽器的乏汽分配管道、凝结水管道和抽真空管道互连互通,利用临机空冷岛1排或2排空冷散热器组为本机的乏汽散热最优,静态投资回收期约为3 a。

A back pressure variation model was developed to study the power supply coal consumption and the ideal internal turbine power as well as the terminal temperature difference of the direct air-cooling condenser.Thus,the effects of the connection design between adjacent air-cooling condensers could be analyzed in real time to optimize the back pressure.The results showed that the present back pressure variation model could be well applied to predict the overall generating efficiency and power supply coal consumption.The net marginal benefits of the back pressure drop,unit output increase and coal consumption reduction were decreasing with increasing the condenser cooling area.The exhaust steam pipes,condensate pipes and vacuum pipes between adjacent condensers could be interconnected to increase the cooling area.One or two rows of air-cooling units in one condenser were optimal to be connected to the other condenser while the static payback period of the retrofit was3years.