350MW超临界循环流化床锅炉水冷壁流量分配及壁温计算

Calculation on distribution of flow rate and temperature in water wall of 350 MW supercritical circulating fluidized bed boiler

以一台350 MW超临界循环流化床锅炉的水冷壁为对象,经合理简化后划分计算回路。通过将集箱抽象为压力节点,并根据回路和节点遵循的质量守恒方程、动量守恒方程、能量守恒方程,建立了超临界循环流化床锅炉水动力计算的数学模型,并对该炉的水动力特性进行了计算分析。计算结果表明,该锅炉左右侧墙中部的流量与前墙和后墙相比偏小,但在BMCR,75%THA,50%THA,30%BMCR的负荷下能够安全、可靠地工作,高度方向最高壁温不超过450℃,10%横向热偏差下的相邻回路横向壁温偏差最大不超过50℃。

This paper investigated the water wall of a 350 MW supercritical circulating fluidized bed boiler,made some reasonable simplification and divided it into calculation circuits. By considering boiler headers as pressure nodes and according to the equations of mass,momentum and energy conservation in circuits and nodes,a hydrodynamics calculation mathematical model for supercritical circulating fluidized bed boiler was built. Based on the model,the hydrodynamics of the boiler was calculated and analyzed. The result shows that the flow rates in the middle part of left wall and right wall are lower than those of front wall and back wall. The boiler can still work safely and reliably under BMCR,75 % THA,50 % THA and 30 % BMCR heat loads,the highest wall temperature in vertical direction is not higher than450 ℃,the highest wall temperature difference at same height in neighbor circuits is lower than 50 ℃ with 10 % horizontal heat load difference.