A study of filtration performance in a cross-flow moving granular bed filter: The influence of gas flow uniformity

• The uniform gas flow was important in moving granular bed filter.
• The uniform gas flow was obtained by adjustment the baffles appropriately.
• The uniform gas distribution caused better pressure drops on filtration surfaces.
• A more uniform gas flow can help to raise filtration performance optimization.

The cross-flow moving granular bed filter where the dust-laden gas passes horizontally through the granular layer and filter granules moves downwards and is removed at the bottom of the bed. It has the advantages of high filtration efficiency and lower pressure drop.The uniformity of gas flow is important for achieving a uniform gas distribution and higher usage rate of the filter media in a cross-flow moving granular bed filter. The behaviors related to the uniformity of the gas flow have been studied in previous experiments. The goal of this study is to evaluate the relationships between a uniform gas flow and filtration performance in a moving granular bed. Filtration performance experiments were carried out at room temperature to understand the relationship between gas flow behavior and filtration performance. The performance index such as the pressure drop in the granular bed and filtration surfaces, and filtration efficiency are measured and analyzed. The different baffle geometries are taken into consideration including baffle length and angle of the gas inlet of the moving granular bed filter. The results indicate that a better filtration efficiency of up to 98.55% can be obtained by using a baffle length of 170 mm, and a baffle angle of 50°. The experimental results show that the filtration efficiency is enhanced when the gas flow becomes more uniform in the gas inlet. The experimental results of filtration performance give important information that will be helpful for designing better models of moving granular bed filters in the future such as for the Integrated Gasification Combined Cycle (IGCC) system.

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