A strategy for tuning aeration for gas—solid flow in standpipes

Abstract

A strategy of aeration based on the direction of continuity wave propagation has been developed to compensate for gas compression in standpipe flow. For the downflow of gas—solid mixture in a standpipe, continuity wave can move either up or down in the pipe. If the continuity wave is in the downward direction, i.e., Type I fluidized flow, tuning of aeration rate should be initiated sequentially from the top. With an upward continuity wave, i.e., Type II fluidized flow, sequential tuning should start from the lower end. For bubbly gas—solid flow in a standpipe, Type I fluidized flow is identified by high solid flowrate and bubbles travelling downwards; Type II fluidized flow is signified by low solid flowrate and bubbles moving upwards. The strategy of aeration developed here is particularly useful as a guide to plant operators in controlling operation of tall industrial standpipes.