Structure optimization of granular bed filter for industrial flue gas filtration containing coagulative particles: An experimental and numerical study

A numerical model for the flow and filtration characteristics of industrial flue gas in granular bed filter (GBF) was established and the local filtration efficiency for different granule layers was investigated. Numerical validation results show that the GBF structure with large size granules at the inlet region and small size granules at the outlet region can effectively improve the filtration performance of GBF and the underlying mechanism was revealed. Then an experimental system was built to validate the suitability of the optimized GBF structure for the filtration of industrial flue gas with coagulative particles. The experimental results show that the optimized GBF structure is also suitable and its superiority is more significant with the increase of filtration time. The results show that the pressure drop and filtration efficiency of the experimental system increase with the increase of dust particles concentration. The existing of coagulative particles is conducive to the growth of smaller size dust particles, the pressure drop and filtration efficiency increase significantly. In addition, the pressure drop and filtration efficiency decrease with the increase of cooling rate. The results of this study are expected to be useful for the design and optimization of industrial flue gas purification and waste heat recovery.