干馏炉内颗粒混合特性的数值研究

摘要

研究制取页岩油优化过程,为了直观地了解干馏炉内颗粒的混合特性,提出了采用离散单元法(DEM)仿真干馏炉内颗粒的混合过程.在Hertz接触理论和牛顿第二定律基础上建立了炉内颗粒运动数学模型,引入颗粒间接触数动态跟踪干馏炉内物料混合进程,以混合质量作为指标对混合程度进行了数值仿真.数值仿真结果表明,当物料休止角大于静态休止角时,物料在重力的作用下下落,呈现出物料层上表面颗粒速度大,外侧区域颗粒速度相对较小的趋势；随着干馏炉的旋转,混合质量基本达到稳定,波动幅度较小.仿真结果为干馏炉热态设计提供了参考.%The discrete element method (DEM) was employed in current paperd in order to investigate the mixing process of particles in retorting. The mathematical model was established based on Hertz theory and Newton's second law. Number of contacts was introduced to track the progress of mixing process and the mixing quality was taken as mixing index to analyse the degree of mixing. The numerical simulation results show that the particles roll down thefree surface under the action of gravity when the angle of repose of particles is greater than static angle of repose,, showing a larger particle velocity in the upper layer and a smaller particle velocity in the outside of region. As the rotary kiln ruining, the mixing quality finally becomes stable with a little fluctuation. The results lay the foundation for thermal process in retorting.