环形流化床生物质热裂解反应器的传热分析

Heat Transfer Analysis of Annular Fluidized Bed Biomass Pyrolysis Reactor

环形流化床热裂解反应器结构紧凑,热效率较高,具有良好的应用前景。本研究对环形流化床内传热过程进行分析。利用解析法,构建了环形反应器稳态传热的计算模型,并用C语言进行编程和求解,得出了反应器各参数随流化气速变化的关系。同时,应用数值法得出相应流化气速下反应器热量损失与壁面温度,并与解析法进行对比。结果显示,反应器在流化气速为0.02～0.24m/s下工作时,随着流化气速的升高,总传热系数上升,燃烧室外壁面温度降低,保温层表面温度升高,单位长度上的热损失呈上升趋势。与传统流化床反应器相比,环形流化床反应器的热损失较低。解析法与数值法得出的结果具有较高吻合性,对于流化床反应器内传热效果的分析具有指导性意义。

Annular fluidized bed reactor possesses a compact structure and higher thermal efficiency, having a good application prospect. The analysis on the heat transfer inside annular fluidized bed is presented. First, the analytic method has been used. In order to study steady heat transfer in the reactor, a kind of computational model is established. And then the C Language is used for programming and solving the process. As the result, the relationship between various parameters of reactor and fluidized gas velocity is carried out. With the numerical method, the heat loss per unit length and temperatures on the each wall of the reactor are obtained by simulation. These values are related with the speeds used in the analytic method, respectively. These results have been compared with the analytic one. The results show that the heat transfer coefficients increase with the rise of fluidized gas velocity. The temperature on the outer wall of combustion chamber decreases, meanwhile the temperature on the outer wall of insulation layer increases. The heat loss per unit length is also on the rise. All above results are obtained with the fluidized gas velocity ranged from 0.02m/s to 0.24m/s. Comparing with the conventional reactor, the heat loss of an annular fluidized bed reactor is much lower. And the results of both methods are consistent with each other. These two methods provide useful guidance for analyzing the effect of heat transfer in a fluidized bed reactor.