Granular bed filter: A promising technology for hot gas clean-up

Hot gas clean-up is important in the integrated gasification combined cycle (IGCC) and advanced pressurized fluidized-bed combustion (PFBC) technologies, which have greater efficiencies and less environmental impacts. The present work attempts to provide a general understanding of granular bed filters, a promising technology for hot gas clean-up. Granular bed filters can be designed as fixed beds, fluidized beds and moving granular beds, and in this paper, their characteristics and performances are summarized and discussed. A fixed bed granular filter has the disadvantage that gas flow must be stopped periodically for cleaning; however, its particle collection efficiency is greater than 99%. A fluidized bed filter provides continuous operation, though it is less efficient at removing small particles. Moving granular beds are promising for hot gas clean-up because typically, they operate continuously with high filtration efficiencies (over 97%) and small pressure losses.