Design And Experiment Of Granular Layer Dust Remover

Granular bed filters is an environmental and efficient dust removing technology, especially applied to high temperature flue gas purification, providing the favorable conditions for the heat and energy recovery. High dust removal efficiency often links to high bed pressure drop, in this thesis, the practical research has been done with fixed granular bed, aiming to explore filtration characteristics and find a way to improve dust removal performance.The article firstly introduces the characteristics and application status of the dust-collecting fans, explaining the structure, advantages and disadvantages of granular bed filter in detail, emphatically typical granular bed filters. After the dust removal theory of the granular layer is analyzed, the unit layer filtering model, dynamic model are created to find the affecting factors on dust removal efficiency and bed pressure drop. Besides, A fixed granular bed experimental apparatus are built up. After the main structure and gas dust generating device are made by using PRO/ENGINEER software, the coarse particles of dust blowing device by using FLUENT software is established. Then the paper introduced the usage of the measuring devices, chose the suitable power plant, experimental dust and filter material, establishing the evaluation index system and analyzing the error in the experimental system. Finally, the experiments with the single granular layer, double granular layers and the tempering dust are finished, the experimental result is particularly analyzed in detail and shows that:In single-layer filter experiment, the slower filtration rate leads to more efficient filtering process. The smaller particle diameter and higher granular layer can increase the dust removal efficiency with the bed pressure drop rising. The higher inlet dust concentrations results in the faster growth of the bed pressure drop. On account of the dust containing capacity, The dust removal efficiency increases first and then decreases over time. The powder can effectively improve the dust removal efficiency.In double-layer filter experiment, the powder between upper layer (l-3mm or3-5mm expanded perlite) and lower layer (0.5～1mm gravel) formed by the deposition of dust can significantly increase the dust removal efficiency. Under the condition of the same dust removal efficiency of the upper layer, the smaller size of the particles in the upper layer can increase the total dust removal efficiency, but the bed pressure drop rises faster. The higher upper layer helps slow the rate of the bed pressure drop rise at the expense of the dust removal efficiency.In the tempering dust experiment, the smaller dust size can increase the dust removal efficiency with the bed pressure drop rising faster. It is an efficient way to increase the dust removal efficiency by adopting the tempering dust, under an absolute filtration of the blowing coarse particles of dust.