不同滤料固定颗粒床过滤性能对比

在固定床冷态实验装置上研究了平均粒径和稳态过滤压降相近、颗粒形状和表面状况不同的两种滤料(陶瓷球和石英砂)的过滤性能. 结果表明，两种滤料过滤性能变化规律基本一致. 粉尘沉积量(?m)增加，过滤效率先增大后减小，过滤压降偏离稳态过滤压降程度(G)增大. ?m相同时，过滤效率和G均随过滤气速增大而减小，但过滤后期高气速下G与低气速下接近. 增大入口粉尘浓度，总体过滤效率无明显改变，粒径大于0.7 ?m的粉尘过滤效率提高，G更显著. 两种滤料难过滤粉尘粒径均为0.35~0.6 μm. 因颗粒形状和表面状况不同，两种滤料过滤性能存在差异，其它条件相同时，石英砂总体和分级过滤效率均高于陶瓷球，G也较大；增大入口粉尘浓度，石英砂过滤效率随粉尘沉积量变化程度相对较小.

Comparison of Filtration Performance in Two Fixed Granular Beds with Different Granules

Similarities and differences of filtration performances of granules were investigated in two beds of ceramic balls and quartz sands. The results showed that the filtration performances of two kinds of granules with similar mean diameter and steady-state filtration pressure drop except for shape and surface condition were basically identical. The filtration efficiency increased at first and then decreased with increasing dust mass deposition (?m), while the deviation degree of pressure drop with steady-state pressure drop (correcting factor, G) presented an increasing trend. The filtration efficiency and G decreased with increasing superficial gas velocity for the same ?m, but G at high superficial gas velocity would be close to G at low superficial gas velocity during the later period of filtration operation. Although there was no significant change in total filtration efficiency, the grade filtration efficiency of dust particles bigger than 0.7 ?m increased when inlet dust concentration increased. At the same time, G under the condition of higher inlet dust concentration was larger. The most penetrant dust particle size was in the range of 0.35~0.6 μm for these two kinds of granules. However, certain differences also existed in filtration performances of these two kinds of granules because of different shape and surface condition. Other conditions being equal, the total and grade filtration efficiency of quartz sands were higher than ceramic balls, and the G of quartz sands was also larger. In addition, the filtration efficiency of quartz sands varying with ?m changed very little with increasing of inlet dust concentration.