温度对生物质热解过程中传热特性的影响

The Influence of Temperature on the Heat Transfer Characteristics of Biomass Pyrolysis

基于欧拉-拉格朗日方法,考虑热解过程中挥发分的析出和颗粒体积的变化,以上海市常见的绿化树种香樟树的树枝为实验材料,对固定床中生物质颗粒热解过程中温度对传热特性的影响进行了详细研究,利用开源软件OpenFOAM获得了反应器内不同热解阶段不同温度范围内颗粒数的分布,给出了不同温度下的有效传热系数及不同传热方式所占的比例。结果表明:热解温度越高,有效传热系数降低,固体颗粒的平均比热容也逐渐降低:同时热解温度越高,辐射的换热量占比越大,而对流提供的热量占比则不断下降。

Considering the precipitation of volatiles and the change of particle volume,the influence of temperature on heat transfer characteristics in a fixed bed was studied during the pyrolysis based on the Euler-Lagrangian method.OpenFOAM was used to simulate the distribution of the number of particles in different temperature ranges in the reactor,the effective heat transfer coefficient at each pyrolysis temperature and the proportion of different heat transfer methods were also given.The results showed that as the pyrolysis temperature increases,the effective heat transfer coefficient also increases,while the average specific heat capacity of solid particles gradually decreases with the increase in particle temperature.At the same time,the higher the pyrolysis temperature,the greater the proportion of heat transfer and radiation,while the proportion of heat provided by convection continues to decrease.