Re-concentration of coking middling particles in a liquid-solid fluidized bed: Fluidization characteristics and density segregation

Abstract

The re-enrichment of coking middling particles is an important way to realize the efficient utilization of coal resources. In this study, by combining numerical simulation and experimental method, the density segregation process and mechanism of coking middling particles in a liquid-solid fluidized bed are studied. The results show that the density segregation process of coking middling particles is mainly divided into the falling outer ring at the sidewall and the rising inner ring. Herein, the ash distribution variance of coking middling particles also shows a changing trend of first increasing and then decreasing with the values increase of operating parameter. Further, after the separation process in the fluidized bed, the cleaned coal product with a yield of 42.77 and an ash content of 8.69% is enriched from 1 to 3 mm coking middling coal (ash content of 28.2%), indicating that coking middling particles are separated efficiently in the liquid-solid fluidized bed.