Coal, as the primary energy resource, could be effectively cleaned with the air dense medium fluidized bed (ADMFB) and have great significance for the society development. In this study, the particle behavior of feed particles with various components was theoretically analyzed. The effect of gas velocity, bed height, and the number of middle particle (Gmiddle) on the separation efficiency was investigated. The results showed that the separation efficiency was directly related to the gas velocity, bed height, and Gmiddle. The mathematical models between the mismatch rate ε and the operational factors were established by the regression analysis. The result shows that the particles with middle density should be removed from the fluidized bed as soon as possible by the technical means to keep the separation density stable and decrease the mismatch ratio.
Keywords: fluidized bed; separation behavior; feed particle; various component; coal beneficiation
As one of the primary energy sources in the world, coal accounts for ∼30% of the energy resources, especially, >65% in China (1,2). In the mining process, many minerals such as quartz and pyrite are associated with coal. Their utilization without pretreatment would cause the environmental pollution with high ash content and discharge of SO2 and NOX. With increasing hazards of the fog and haze, more importance should be focused on the burning of coal (3,4). Currently, the desulfurization and deashing before combustion is an effective method for the coal clean utilization. The means of flotation column, water jigging, TBS, and other ...
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...o used as the additional medium in the separation bed to adjust the bed density and broaden the size fraction of the medium. Moreover, the content of coal powder used in the study was 10%.
As shown in Fig. 2, the particles with a density of 1.4 g/cm3 (yellow), 1.6 g/cm3 (red), and 1.8 g/cm3 (blue) were used for simulating the light density particle (LDP) middle density particle (MDP),and heavy density particle (HDP), respectively. In order to eliminate the negative effect of the size fraction, the particles with a size fraction of 22 mm were used to investigate the particle separation behavior, and the feed particle number was controlled (18) every time. In the experiment, the composition of particles was adjusted by controlling the number of middle density particle (Gmiddle), which was respectively feed with the number of 0, 2, 4, 6, 8, and10 in the separation bed.
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