加压密相气力输送空隙率的实验

Experimental Research of Voidage of Pressurized Dense-Phase Pneumatic Conveying

在加压密相气力输送中试实验台上进行内蒙烟煤的输送特性实验,考察操作条件和物性参数对空隙率的影响规律.结果表明:提高输送压力有利于实现较低空隙率的输送;随着流化风量的增大,空隙率先减小后增大;补充风量的增大会提高空隙率;随着总差压的增大,52μm煤粉的空隙率先减小后增大,而115和300μm煤粉的提升段空隙率持续增大,且同一总差压下,粒径较大煤粉对应的提升段空隙率较小;煤粉水分的增加会降低固相体积流量,同时增大两相流空隙率;随着表观气速的减小,300μm煤粉的流型从悬浮流向沙丘流转变,管路空隙率逐渐减小.

Experiments on the conveying characteristics of Inner Mongolia bituminous coal powder were conducted on a pilot-scale pressurized pneumatic conveying test rig. Effects of operational conditions and material properties on the voidage ε were explored respectively. The results indicate that increasing the conveying pressure p is beneficial for conveying at a lower ε,ε initially drops and then grows with the rise in the flow rate of fluidizing gas Qf, Increase of supplemental gas Qsp leads to a higher ε. With the increase of total differential pressure Ap, Δp,ε of 52 μm coal decreases at first and then increases marginally, whereas the voidages in the riser section εr of 115 μm and 300 μm coal both rise continually. εr of pulverized coal with larger particle size exhibits a lower voidage at the same Δp. Increase of the moisture content M of coal results in a lower volumetric flow rate of solids and a higher volidage of the two phase flow. With the decrease of superficial gas velocity Vg, the flow regime of 300μm coal changes from suspended flow to slug flow, while the volidge in the pipeline εp declines gradually.