Downer reactor has been widely used in carrying out multiphase processes in the recent decade. The nature and introduction of particles in the downer has its own characteristics to achieve uniform and well dispersed flow. This creates a necessity to design a distributor for achieving uniform dispersion of particles in a short distance. The present study explores the use of CFD with different distributor configurations to design an effective distributor for dispersion of ultrafine cohesive particles. In the present study, the ultrafine cohesive powder considered is petcoke of mean particle size 60 μm and estimated Carr’s index of 30.83. The downer reactor is of 200 mm diameter and 8 m long. The solid particles are fed through a screw feeder above gas distributor. Different distributor designs are considered for assessing the dispersion using Fluent ANSYS v19.0. The results from the investigation indicate that there is a strong influence of jet velocities and pressure distribution in the distributor on dispersion of cohesive particles. The present study highlights the use of CFD in numerical experimentation in identifying the appropriate designs suitable for cohesive ultrafine particulate systems.

在最近十年中，唐纳反应器已广泛用于进行多相过程。下降器中颗粒的性质和引入具有其自身的特性，以实现均匀且良好分散的流动。这就需要设计一种用于在短距离内实现颗粒均匀分散的分配器。本研究探索了使用具有不同分配器配置的CFD来设计用于分散超细粘性颗粒的有效分配器。在本研究中，所考虑的超细粘性粉末是平均粒径为60μm的石油焦，估计的卡尔指数为30.83。下降反应器的直径为200毫米，长度为8 m。固体颗粒通过气体分配器上方的螺旋进料器进料。考虑使用不同的分配器设计来使用Fluent ANSYS v19.0评估色散。研究的结果表明，分配器中的射流速度和压力分布对粘性颗粒的分散有很大影响。本研究强调了在数值实验中使用CFD来确定适用于粘性超细颗粒系统的适当设计。