超超临界直流锅炉受热面传热运行预测方法及在水煤比调整中应用

Heat Transfer Forecasting in Ultra-supercritical Pressure Once-Through Boiler and It's Use in Coal and Water Flow Ratio Regulation

给出一个包含受热面结构参数的传热系数,对于超临界锅炉,由于工质侧的传热阻力可以忽略,该传热系数只和烟气侧的参数有关。并可以表示成锅炉燃煤量的函数,通过试验得到了传热系数和燃煤量的关系式。假设吸热量较少的附加受热面和主受热面串联,整台锅炉是一个受热面首位相接的热交换网络,利用受热面的能量平衡方程,建立了基于实际运行数据的超临界直流锅炉静态传热模型,该模型较为接近锅炉设计热力计算模型,但它不需要复杂的受热面的信息,因而,具有便于应用的特点。在不同的煤量和水量下,利用该模型模拟了超临界直流锅炉受热面的换热,给出了水煤比的报警运行曲线,对运行有指导意义。

A kind of heat transfer coefficient comprising configuration parameters of heating surface is given in this paper, which is bear upon flue gas parameters and can be figure with coal fired in ultra-supercritical once-through boiler, because the heat resistance on water or steam side can be ignored, correlation of the heat transfer coefficient with the coal flow is obtained by experiment. On the assumption that the accessorial heating surfaces and it＇s main one are series-wound, the boiler can be considered as a heat transfer network consist of heating surfaces connected to each other in series, static heat transfer model for ultra-supercritical once-through boiler is put forward consists of energy balance equations for each heating surface, this model is similar with the thermal calculation model used in boiler design, but needs no information about boiler heating surfaces, so it is simple and easy to use. In different of coal and water flow combination, the heat transferred and the steam temperature in each heating surface are simulated, water flow alarming curve is given when the boiler is firing different amount of coal, this is helpful for boiler operation.