低低温省煤器联合暖风器系统运行优化

摘要

To explore the optimum operation mode for the operation optimization of the low-temperature economizer combined heater system under different loads,operation optimization test is carried out in a 300 MW unit.The results show that ambient air temperature is basically unchanged and the temperature of the boiler exhaust shows a linearly increasing trend with the increased air temperature of the air heater.With the temperature rise of the air heater,the heat exchange proportion of the air heater increases approximately linearly at medium and high loads,and at low load the ratio increases at first and then tends to be gentle.Based on the outage state of the low-low temperature economizer combined heater system,within the experimental range,the reduction of the heat rate of steam turbine is linear with the recuperated heat,the increase of the thermal efficiency of the boiler is positively correlated with the increase of air temperature of the air heater outlet,the decrease of coal consumption of power supply is positively correlated with the increase of air temperature of the air heater outlet and the proportion of the absorbed heat at the air heater side.In actual operation,when the air temperature of the air heater outlet is controlled at 70 ℃,the economy of the overall unit is best.The results of this study provide some technical references for improving the economy of thermal power units.%为了探索不同负荷下低低温省煤器联合暖风器系统运行优化的最佳运行方式,依托某300 MW机组进行了运行优化研究.结果表明:环境空气温度基本一致,锅炉排烟温度随空气在暖风器温升呈线性增加趋势;随暖风器温升,中高负荷下暖风器热交换量占比呈近似线性增加,低负荷下呈先增高后趋于平缓的趋势;以低低温省煤器联合暖风器系统停运状态为基准,试验范围内汽轮机热耗率降低值随回收热量呈近似线性正比关系,锅炉热效率提高值随暖风器出口风温升高值呈正相关关系;试验范围内供电煤耗下降值随暖风器出口风温升高呈正相关关系,与暖风器侧吸收热量占比升高呈总体正相关关系;实际运行中控制暖风器出口风温在 70 ℃时机组整体经济性最佳.该结果可为提高火电机组运行经济性提供一定的技术参考.