Experimental and numerical study on characteristics and mechanism of particles attrition in fluidized bed

Particle attrition is commonly existed in gas-solid two-phase flow process. A novel CFD-DEM particle attrition model is developed, a series of experiments/simulation studies are performed to quantitatively investigate the attrition mechanism of particles in fluidized beds. The particle attrition process could generally be divided into unstable attrition stage and stable attrition stage, while the results show that unsteady attrition stage should be subdivided into high-speed attrition phase and low-speed attrition phase. Both wear and fragmentation become more intense with increasing height-diameter ratio and superficial gas velocity. The wear ratio decreases with increasing particle size, while the fragmentation ratio firstly decreases and then increases. Particle attrition mechanism also presents spatial ununiformity, particles reaching the bottom are worn most significantly, while the proportion of fragmentation based on this study for the sidewall areas, the bottom area and the center area is about 69%, 22% and 9% respectively.

Automated summary

A novel CFD-DEM particle attrition model is developed to investigate the attrition mechanism of particles in fluidized beds. The results show that the attrition process can be divided into unstable attrition stage and stable attrition stage, with the former further divided into high-speed attrition phase and low-speed attrition phase. Wear and fragmentation increase with increasing height-diameter ratio and superficial gas velocity. The wear ratio decreases with increasing particle size, while the fragmentation ratio first decreases and then increases. Particle attrition mechanism also exhibits spatial non-uniformity.