循环流化床锅炉热惯性分析

An Analysis of Thermal Inertia of a CFB(Circulating Fluidized Bed) boiler

循环流化床锅炉的热惯性是影响锅炉动态特性的重要因素。从动态能量平衡的角度定义了循环流化床锅炉的热惯性。分别针对6种不同容量等级的锅炉计算了其能量传递各环节的热惯性大小。计算结果表明:锅炉总热惯性的大小随锅炉容量的增大而增加,但单位蒸发量却随锅炉容量的增大而减小;工质和耐火材料热惯性是能量传递过程中的控制环节;对于省煤器而言,金属热惯性与工质热惯性同等重要;过/再热器中耐火材料与金属热惯性处于相同量级;水冷壁/屏中,工质热惯性最大。

The thermal inertia of a CFB(Circulating Fluidized Bed) boiler represents an important factor affecting the boiler dynamic characteristics.From the standpoint of a dynamic energy balance,defined was the thermal inertia of the CFB boiler.For boilers rated at 6 different capacities,calculated respectively were their thermal inertia magnitudes in various links of energy transfer.The calculation results show that the total thermal inertia magnitude of a boiler increases with an increase of its capacity,however,its unit evaporative capacity decreases with an increase of its capacity.Thermal inertia of a working medium and refractory materials constitutes a control link in the energy transfer process.As far as an economizer is concerned,metallic thermal inertia is of equal importance to that of a working medium.The thermal inertia of refractory materials in superheaters/reheaters is of the same magnitude order as the metallic thermal inertia.In water walls/panels,the working medium thermal inertia is considered as the biggest.