Fluidization Characteristics of a Fine Magnetite Powder Fluidized Bed for Density-Based Dry Separation of Coal

摘要

Gas-solid fluidized bed separation technique is very beneficial for saving water resources and for the clean utilization of coal resource. The hydrodynamics of 0.15-0.06Â mm fine Geldart B magnetite powder were experimentally and numerically studied to decrease the lower size limit. The results show that the static bed height should be controlled near 300Â mm (e.g., 300-350Â mm). The bubble size, amount, and frequency of the fine particle bed are smaller than those of the bed containing 0.3-0.15Â mm large Geldart B particles, thus leading to a higher bed activity. The pressure drop and density of the fine particle bed are uniform and stable, which indicates a good fluidization quality. Furthermore, simulated results are consistent with experimental data, which indicates the correctness and effectiveness of the simulations. The superficial gas velocity should be adjusted to not more than 1.8U _mf for the fine particle bed. Additionally, wide size range magnetite powder, which contains 94.23Â wt%Â Â 0.3Â mm particles with a 0.3-0.06Â mm particles content of 91.38Â wt%, was used in an industrial scale modularized demonstration system for 50-6Â mm coal density separation. The ash content of feed coal was reduced from 55.35% to 14.67% with a probable error, E, value of 0.06Â g/cm3. View full textDownload full textKeywordsdensity, dry separation of coal, fluidization characteristic, gas-solid fluidized bed, numerical simulation, wide-size-range medium-solidsRelated var addthis_config = { ui_cobrand: "Taylor & Francis Online", services_compact: "citeulike,netvibes,twitter,technorati,delicious,linkedin,facebook,stumbleupon,digg,google,more", pubid: "ra-4dff56cd6bb1830b" }; Add to shortlist Link Permalink http://dx.doi.org/10.1080/01496395.2012.669805