宽粒级加重质的流化特性

为拓宽气固流化床干法选煤加重质的粒级范围,分别配制了B-A型磁铁矿粉和B-A型粉煤,并按一定比例将两者混合作为宽粒级加重质,研究了其流化特性及分选性能,结果表明:由于A类颗粒中较细及密度较小物料的影响,随着床高增大,床层密度逐渐降低,且密度分布标准偏差较大,为0.060 1 g/cm~3.在合理的工艺及操作参数条件下,处于循环状态的0.3～0.074 mm级磁铁矿粉和1～0.15 mm级粉煤在流化床中分布均匀,床层密度均匀稳定,宽粒级加重质的流化性能良好,用于分选50～6 mm煤炭,分选密度为1.61 g/cm~3时,可能偏差(E值)为0.06 g/cm~3,分选精度较高.

Fluidization Characteristics of Medium Solids with a Wide Size Range

To expand the suitable size range of medium solids used in gas-solids fluidized beds for dry separation of coal, a type B-A magnetite powder and type B-A fine coal with a specific size distribution were mixed at a specific ratio of weight. The fluidization characteristics and separation performances of the mixture with a wide size range were studied. The results show that in the presence of particles with smaller size or lower density in group A powders,the bed density decreases gradually with the increasing of bed height with a high density standard devi-ation value of 0. 060 1 g/cm~3. Both magnetite powder with 0.3-0. 074 mm size and fine coal with 1-0.15 mm size distribute uniformly in a commercial gas-solids fluidized bed with uni-form and stable density, and the fluidization performances of recycled medium solids with a wide size range of 1-0. 074 mm are very good under suitable technical and operating parame-ters. The commercial fluidized bed using medium solids with a wide size range of 1-0. 074 mm can efficiently separate coal of 50-6 mm size with a low probable error E value of 0.06 g/cm~3 at a separating density of 1.61 g/cm~3.