裤衩型循环流化床动态数学模型研究

Dynamic Mathematic Modeling Study on Circulating Fluidized Bed with Breeches-legs

在两段循环流化床动态仿真模型的基础上,通过考虑裤衩腿循环流化床两侧炉膛间风量和物料的横向交换对流化床动态特性的影响,建立了裤衩腿型循环流化床的动态数学模型.利用计算流体力学软件对冷态的裤衩腿循环流化床内的风烟流动进行了模拟,得到两侧炉膛给风量不一致时横向风量交换量的计算方法.重点分析了横向气体交换量、物料交换量与两侧炉膛给风量之间的相互关系,建立了裤衩腿型循环流化床内横向物料流量与横向气体流量之间的关系式.将模拟得到的床料压降与床温的变化与实际"翻床"过程中的变化进行了比较,结果表明:模型结果能够正确反映裤衩腿循环流化床的"翻床"过程.

Based on a dynamic simulation model of two-stage circulating fluidized bed（CFB）,a dynamic mathematic model was established for the CFB with breeches-legs considering the effect of the cross exchange of air flow and solid material between the two furnaces of the CFB with breeches-legs on the dynamic characteristics of the fluidized bed.Computational fluid mechanics software was used to simulate the air and gas flow inside the cold CFB with breeches-legs,and a calculating method was obtained for the cross exchange amount of the air when the flow rate of the feed air of the two furnaces were different.The relationship of the cross exchange amount of the air and material varying with the flow rate of the feed air of the two furnaces was analyzed with emphasis.And a formula was set up for the relationship between cross exchange amount of the material and gas.The simulated pressure drop of the bed material and variation of bed temperature were compared with the variations during actural ＂bed overturn＂.Results show that the model results can correctly reflect the ＂bed overturn＂ process of the CFB with breeches-legs.