超/超临界循环流化床锅炉整体数值模型

Integrated Numerical Model for Ultra/Supercritical CFB Boilers

建立和发展了一个适用于大型超/超临界循环流化床锅炉的综合数值模型。该模型不仅能够预测锅炉的燃烧、传热及污染物排放特性,还同时考虑水冷壁管内外传热及水动力耦合过程。模型的流场基于欧拉两相流模型和EMMS曳力模型;燃烧采用考虑了水分蒸发、挥发分析出、焦炭燃烧、气相反应以及燃烧污染产物等过程的组分反应模型,其中包括脱硫反应和氮氧化物生成反应;壁面传热基于颗粒团更新传热模型和离散坐标辐射模型,考虑水冷壁内工质超临界状态下的热工水动力过程,在燃烧模型中对炉内、外进行耦合计算。提出的循环流化床锅炉整体模型成功应用于炉膛容积为1300m3的350MW（e）超临界循环流化床锅炉,得到炉膛气固流场、温度、热流、包括硫、氮化合物的燃烧产物三维分布结果。

This work introduced a newly developed integrated numerical model for uttra/supercritical CFB boilers, which can predict the combustion, temperature profile, heat transfer, emissions with considering the heat transfer coupling between the thermal hydraulics in wall- tube and furnace in a large-scale ultra/supercritical CFB boiler. Based on the gas-solid hydrodynamics results computed by the Euler-Euler model and EMMS drag model, the coal combustion is taken into consideration by species reaction model, which consists of evaporation, devolatilization, char combustion, gas homogeneous reaction and pollutants emission. In the model, heat transfer process between heat-exchange surfaces and furnace is based on the cluster renewal model and the discrete ordinate radiation model. To consider the boiler operating under supercritical condition, the thermal hydraulics in the membrane wall tube is coupled with wall heat transfer. This integrated numerical model was successfully applied to a 350MWe supercritical boiler. The reasonable 3D distributions of gas-solid suspension density, temperature profile in furnace and heat flux on waterwall were obtained.