基于燃煤锅炉热力系统建模的受热面传热特性

Heat transfer characteristics of heating surface based on thermal system modeling of coal-fired boiler

燃煤发电机组在当前能源利用现状下负荷多变,火电锅炉的在线监测与运行评估精度需求日益增加。为获取高精度机组运行参数,拓宽适宜煤种的选择方法,基于试验数据利用Ebsilon16.4仿真软件构建了燃煤锅炉的热力系统模型。针对煤种煤质计算了各换热部件的热量变化情况,分析了一次风温对热力系统计算的影响。结果表明,在实际工程数据下,采用模拟方式获取锅炉受热面数据更准确与便捷。模拟结果中,位于炉膛中心的换热器如屏式过热器、高温再热器等换热占比较大,因此煤质对其影响较大;一次风温通过影响烟气温度,间接改变换热器的吸热,位于烟道尾部竖井的省煤器、低温再热器等换热占比较小,因此煤质对其影响较小。同时,模型的参数设置及模拟结论可为超临界燃煤机组的深度调峰、锅炉数据的高效获取提供参考。

The load of coal-fired power generation units is variable under the current situation of energy utilization,and the online monitoring and operation evaluation accuracy of thermal power boilers needs increasing day by day.In order to obtain the operation parameters of high-precision units and broaden the selection method of suitable coal,the thermal system model of coal-fired boilers was constructed by Ebsilon16.4 simulation software based on experimental data.According to the coal type and quality,the heat change of each heat exchange component was calculated,and the influence of primary air temperature on the calculation of thermal system was analyzed.The results show that the simulation method is more accurate and convenient to obtain the boiler heating surface data under the actual engineering data.In the simulation results,the heat transfer of heat exchangers located in the center of the furnace,such as plate superheater and high temperature reheater,is relatively large,so the coal quality has a great influence on it.The primary air temperature indirectly changes the heat absorption of the heat exchanger by affecting the flue gas temperature,and the economizer and low-temperature reheater located in the shaft at the tail of the flue account for a relatively small amount of heat exchange,so the coal quality has little influence on it.At the same time,the parameter setting of the model and the simulation conclusion can provide a reference for the deep peaking of supercritical coalfired units and the efficient acquisition of boiler data.