【摘要】 以某 6 0t·h-1增压流化床锅炉为对象 ,建立了动态数学模型 .模型采用了分小室和分段结合的离散化方法 ,以反映沿炉膛高度方向上温度的分布特性 ;通过描述密相床内不同相区间的气体交换现象 ,使得模型能够模拟氧气通过气泡短路通过密相床的现象 ;以动态固体质量平衡、氧质量平衡、碳质量平衡和总体能量平衡为主体建立动态数学模型 .模型稳态计算结果与实际电厂的运行数据对比 ,表明模型具有一定的定量准确性 .文中最后对快排床料的动态过程进行了仿真和分析 ,结果表明所建模型可以模拟“快加快排”这种增压流化床特有的变负荷方式 ,也较为本质地反映了增压流化床的燃烧机制更多还原

【Abstract】 The dynamic model of a pressurized fluidized bed combustor was studied. In order to reflect the distribution of temperature along the axial direction as well as to increase the speed of model calculation, a combined discretization strategy was applied, which divided the combustor into a certain number of cells for hydrodynamic and heat transfer calculations and further grouped some neighboring cells into a smaller number of sections for mass and energy balance calculations. By dividing the dense bed into three different phases and considering the bubble behavior and gas mass transfer between the adjacent phases, the model was able to simulate the bypassing of oxygen from bottom to the freeboard as well as the difference of oxygen concentration in different phases. The dynamic model was set up based on the dynamic balance equations of solid mass, oxygen mass, carbon mass and total energy in each section. The static balance calculation results of the model were compared with the experimental data from a real 60 t·h -1 PFBC boiler and agreement was found to some extent. Finally, the fast bottom ash draining process was simulated with the model, which showed that the model indeed had the ability to describe this unique load changing operation of PFBC correctly and reflected the combustion mechanism of fluidized bed essentially.更多还原