卧式搅拌床内生物质颗粒的轴向混合与停留时间

THE AXIAL MIXING AND RESIDENCE TIME OF BIOMASS PARTICLES IN A HORIZONTAL SITRRED BED REACTOR

采用离散单元法（DEM）模拟卧式搅拌床内非球形大颗粒流动过程并进行实验检验。对颗粒流场进行分析，讨论颗粒性质和结构参数对颗粒流动行为的影响。结果表明：轴向扩散系数随颗粒尺寸、反应器尺寸的增大以及叶片与壁面间隙的减小而增大。挡板高度增大时，轴向扩散系数先增大后减小。平均停留时间随颗粒尺寸的减小，反应器直径、挡板高度的增大以及叶片与壁面间隙的增大而增大。停留时间相对方差则随颗粒尺寸、反应器直径、挡板高度的增大以及叶片与壁面间隙的减小而增大。材料的颗粒密度对于卧式搅拌床内轴向混合及停留时间分布并无显著影响。

The discrete element method （DEM） was used for the simulation of flow behavior of large non-spherical biomass particles in the horizontal stirred bed reactor （HSBR） and experiment was conducted to test the results. The effect of particle properties and design parameters on flow characteristics of biomass particles was discussed by the simulation results. The results indicates that the axial dispersion coefficients increased with the increase of particle size, diameter of the reactor and the decrease of the gap between the blade and wall. As the height of the weir increased, the axial dispersion coefficients increased at first and then decreased. The mean residence time increased with the decrease of particle size and the increase of diameter of the reactor, the height of the weir and the gap between the blade and wall. The relative variance of residence time increased with the increase of particle size, diameter of the reactor and the height of the weir and the decrease of the gap between the blade and wall. The effect of density of the particle on the axial mixing and residence time distribution was minimal.