Filtration of dust particulates with a granular bed filter in a novel coupled separator

In this study, the filtration performance of the built-in granular bed in a cyclone-granular bed coupled separator is investigated. Cyclone is used to recover catalyst particles from the regenerated flue gas in the Fluid catalytic cracking by centrifugal force. While the granular bed captures fine dust particles smaller than 10 μm. Catalyst loss problem can be addressed by coupling different separation mechanisms in the coupled separator. To clarify the separation process, the necessity to elucidate the filtration performance is shown The investigation has been performed for the velocity distribution measuring and the bed dust deposition, and the filtration efficiency in the coupled separator under varying operating parameters. Experimental results indicate that the radial velocity component is a main influencing factor on the granular bed filtration efficiency. The outer-layer bed collector particles exhibit superior dust collection capabilities. Based on the intrusive dust sampling, a diagram is presented to clearly illustrate the primary mechanisms that govern dust movement in the bed. Furthermore, two parameters named by the local filtration efficiency (LFE) and the filtration efficiency across radius (FEAR) are proposed for analyzing the granular bed filter performance. The LFE exhibits a declining trend as the inlet air velocity increases. The dust size distribution analysis highlights the capacity of the bed to capture fine dust particles (<5 μm) which tended to accumulate at the inner layer. The FEAR, ranging from 91 % to 97 %, offers a comprehensive assessment of the coupled separator performance and structural optimization.