多孔板干扰床中细粒煤分离特性研究

为提高干扰床对细粒煤的分选效果,将一种多孔板应用于干扰床,采用实验与数值模拟相结合的方法,研究了多孔板对细粒煤分选密度、颗粒分布的影响及多孔板干扰床的流化特性。结果表明:多孔板使各粒级分选密度更加均匀,粒度-分选密度曲线斜率由-0.518增至-0.448,强化了颗粒的密度分离,提高了分选效果。高密度颗粒(1.70、1.90 g/cm3)主要集中在床层底部,低密度颗粒(1.40、1.50 g/cm3)主要集中在床层上部,其体积分数分别为29.79%、32.86%、48.90%、20.81%,错配颗粒比较少,实现了煤粒的有效分选。干扰床床层悬浮区密度不是煤粒分选密度,其平均值为1.23 g/cm3,且在高度方向上并不均匀。多孔板干扰床中形成了多孔板分级—板间流化区—多孔板与边壁间流化区的多级分选模式,能在一定程度上抑制高低密度颗粒错配,实现细粒煤的高效分选。 In order to increase the separation performance of normal hindered fluidized bed for fine coal,the perforated plates were designed in this work.The separation characteristics of fine coal in the bed with perforated plate were investigated using a combination of experimental and numerical simulation methods.The results showed that the perforated plate were beneficial for the uniformity of separation density of each particle size range.The slope of particle size-separation density curve was increased from-0.518 to-0.448.The density separation of particles and separation performance were increased.The high-density particles(1.70 and 1.90 g / cm3) distributed at the bottom of bed.Their volume fractions were 29.79% and 32.86% respectively.The low-density particles(1.40 and 1.50 g / cm3) distributed at the upper of bed.Their volume fractions were 48.90% and 20.81% respectively.The misplaced particles were less,so the coal particles can be separated effectively.Furthermore,the density of suspension zone of bed wasn't the separation density.The fluidization density was 1.23 g / cm3 which was uneven along the height direction.The multi-stage separation model,including perforated plates,flluidized zone among plates and the bed wall could inhibit the mismatch of high-density and low-density particles,meanwhile,separate the fine coal effectively