Gas—solid flow in a novel standpipe

Abstract A novel standpipe has been designed and its performance characteristics discussed in this paper. The proposed standpipe is a combination of the over- and under-flow standpipe concepts and offers the advantages of both. While the outlet of an overflow standpipe has to be immersed in a fluidized bed, the outlet of this new configuration need not be. The standpipe discussed in the paper is characterized by the absence of a mechanical valve and by its ability to adjust the pressure drop across the standpipe to balance the pressure drop through the entire system. While an L-valve imposes restrictions on the standpipe dimensions, the proposed standpipe configuration does not. The experiments showed that larger solids, or agglomerates, could be discharged very easily through the opening at the bottom of the first column of the standpipe and the solids flowrate could be adjusted by aeration through both the first and the second column. The new standpipe has a good operating stability and it offers significant ease of control.