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| Characteristics of dense medium agglomerate fluidization and coal separation in gas-solid fluidized beds |
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Received:March 24, 2025
Revised:June 23, 2025
Accepted:October 24, 2025
Published Online:April 30, 2026
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| DOI：10.3969/j.issn.1005-7854.2026.02.008 |
| KeyWord:dry coal separation;particle agglomeration;bed density;coal moisture |
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| 1.State Power Construction Investment Inner Mongolia Energy Co., Ltd., Ordos 017209, Inner Mongolia, China;2.Dadi Engineering Devel-opment Group Co., Ltd., Beijing 100102, China;3.School of Chemical Engineering & Technology, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China |
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| Abstract: |
| The fluidized separation technology is an extension of gas-solid fluidized beds in the field of separation, enabling effective separation of coal. By utilizing magnetite powder and coal powder as dense medium, a bed with a certain density is formed under the influence of upward airflow. Low-density clean coal rises to the top of the fluidized bed, while high-density gangue settles at the bottom. However, if the moisture content of the selected coal is relatively high, particle agglomeration may occur between coal-dense medium agent and dense medium-dense medium interactions. This results in an uneven distribution of bed density that hinders efficient separation of coal. This study investigates the content and distribution characteristics of both coal and agglomerates within the bed under varying external moisture contents in coal. It explores how external moisture content affects changes in bed density and conducts separation experiments on moist coals to examine its impact on sorting outcomes. The results indicate that increasing external moisture significantly influences the distribution patterns of both coal and its agglomerates. Low-density coals and their agglomerates are primarily concentrated in the upper part of the bed; however, as external moisture increases, some agglomerates tend to sink. High-density gangue mainly accumulates at lower sections of the bed; with rising external moisture levels, both quantity and depth placement of agglomerates increase progressively deeper into layers. Nonetheless, due to increased density at lower layers caused by higher water content in coals, some agglomerates exhibit buoyancy effects as well. Additionally, because adhesive forces play a role here—higher external water content facilitates easier formation of aggregates between coals and dense medium particles—this leads to challenges for complete expansion within beds characterized by higher densities accompanied by greater standard deviations. Under conditions where external water content is zero, potential deviation measures 0.082 g·cm?3 while separating density registers at 1.844 g·cm?3. This research lays a theoretical foundation for regulating and inhibiting particle agglomeration within gas-solid separation fluidized beds aimed at achieving effective sorting for moist coals. |
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