宽筛分颗粒流化特性实验研究

Experimental Study on the Fluidization Characteristics of Wide Size Particles

通过实验,比较系统地研究了气固流化床内,不同筛分组合的颗粒在流化状态时的气泡特征、轴向固含量和颗粒粒径分布、床层空隙率等特征。实验结果显示:宽筛分物系中的细颗粒,一方面可提高气泡聚并破碎频率,从而抑制大气泡的产生;另一方面可使颗粒整体流化高度增加,提高轴向固含量分布的均匀性及流化状态的稳定性。实验结果也表明,在表观气速一定的条件下,若逐渐增大颗粒粒径,则流化床空隙率逐步减小,细颗粒可有效地提高床层空隙率。

The bubble characteristics, axial solid content, particle size distribution and bed voidage of particles with different size combinations in fluidization state were systematically studied with experiments. Experimental results showed that the fine particles in wide size materials improved the bubble coalescence and breakage frequency, thus inhibiting the formation of big bubbles; it increased the overall fluidization height of the particles and improved the uniformity of the axial solid content distribution and the stability of the fluidization. The experimental results also indicated that when the particle size increased gradually, the porosity of the fluidized bed gradually decreased under certain apparent gas velocity. So fine particles can effectively increase the porosity of the bed.