Filtration of dust in an electrostatically enhanced granular bed filter for high temperature gas cleanup

High temperature gas cleanup is an important technology. In order to develop an efficient filter for hot gas cleanup, three kinds of filters were built: 1) Rare earth tungsten (RE-W) cathode electrostatic precipitator (ESP), 2) classical granular bed filter (CGBF), and 3) electrostatically enhanced granular bed filter (EGBF). The effect of gas temperature, voltage, granule size, and bed height on the dust collection efficiency of the filters were investigated. It is found that the efficiency of the EGBF is the highest among the three filters. The efficiency of the double-zone RE-W cathode ESP ranks second, though decreasing collection area reduces the efficiency significantly. The efficiency of the CGBF is not high compared to the above two filters. On the whole, the EGBF is a very promising technology for hot gas cleanup, especially when cooperated with the RE-W thermionic emission cathode which is very suitable for particle charging at high temperature. [Display omitted] •Dust collection efficiencies of three kinds of filters were studied experimentally.•The influences of several factors on the filter efficiency were analyzed.•EGBF with rare earth tungsten cathode shows great potential for hot gas cleanup.