Effect of a draft tube on oil shale particle drying process of a spouted bed: CPFD simulation studies

Abstract

Material drying pretreatment plays an important role in the oil shale retorting process. In this study, the drying process of particulate oil shale in a spouted bed was simulated using computational particle fluid dynamics numerical schemes. This study analyzes the effect of the draft tube and inlet air temperature on the drying rate and drying uniformity, and establishes a new insight into the drying process and multiphase flow characteristics inside the spouted bed. The results indicate that using an ordinary cylindrical spouted bed results in a poor drying uniformity, which causing by a large number of the annulus-region particles fall into the spout region from the height of approximately 150 mm and resulting in a stirless area usually observed at the height of 50–150 mm near the wall. Inserting the draft tube and reducing the drying temperature can improve the uniformity of the drying process, and the former is more efficient than the latter.