空气重介质流化床流化特性及密度梯度分布研究  

Fluidizing characteristics and density gradient distribution of air dense medium fluidized bed

作　　者：张翠玉[1] 

机构地区：[1]中国煤炭科工集团北京华宇工程有限公司,河南平顶山467002

出　　处：《洁净煤技术》2014年第3期12-15,共4页Clean Coal Technology

摘　　要：为实现物料的有效分选，以磁铁矿粉和玻璃微粉为混合加重质，研究了混合加重质的流化特性及空气重介质流化床床层密度梯度分布情况。结果表明：空气重介质流化床形成了均匀稳定的流化状态。当流化气速大于7．10cm／s后，床层压降基本维持在510Pa．床层密度基本不变。为1．71～1．74g/cm^3。当流化气速为7．95cm／s时，流化床内气泡直径为15～25mm，且分布均匀，流化床各层平均密度从上至下依次为1．72、1．74、1．74、1．74、1．73g/cm^3。流化床上部区域，超微细玻璃微粉被气流带到床层表面，使表面床层密度较小；流化床底部区域，气体分布相对均匀，并未形成大气泡，使该区域流化床床层平均密度偏小：而床层大部分区域床层平均密度均为1．74g/cm^3，比较稳定。因此，当流化气速为7．95cm／s时．流化床内并未形成明显的分层和分级现象，说明加重质混合比较均匀．为空气重介质流化床分选物料创造良好条件。To separate material effectively,investigate the fluidization characteristics of mixed mediums and density gradient distribution of air dense medium fluidized bed using mixed medium of magnetite powder and glass spheric particles.The experimental results show that air dense medium fluidized bed can form a uniform and stable fluidization state.When the fluidizing air velocity is above 7.10 cm/s, the pressure drop of bed can hold around 510 Pa,the bed density stabilize between 1.71 g/cm3 and 1.74 g/cm3.When the fluidizing air velocity is 7.95 cm/s ,the bubble distributed evenly in the bed with the diameter of 15 mm to 25 mm.The average density of each floor of fluidized bed is 1.72,1.74, 1.74,1.74,1.73 g/cm3 from top to bottom.On the top area of fluidized bed,the micro-fine glass spheric particles can be carried up to the surface of bed by flowing vapor and decrease the density of top area.The gas is evenly distributed on the bottom of bed and decrease the density of the bottom area.The average density of most area is 1.74 g/cm3. So when the fluidizing air velocity is 7.95 cm/s, there is no obvious stratification and classification phenomenon.The results show that the mixed medium with evenly density create good conditions for material separation of air dense medium fluidized bed.

关 键 词：空气重介质流化床 混合加重质 流化气速 密度梯度 

分 类 号：TD94[矿业工程—选矿]