Influence of the pressure drop and the air lock on the solid flux in a cross-flow moving bed

Abstract The gas–solid flow pattern in a rectangular cross-flow moving bed is simulated by the multiphase particle-in-cell (MP-PIC) model with the Barracuda software. The computed results are verified by the experimental data. In the bed, the actual solid flux generally equals the solid flow rates in the solid feed and discharge tubes. However, these two flow rates are greatly influenced by the air lock and the pressure drop in the solid feed and discharge tubes, namely, the negative and positive pressure gradients, respectively, rather than the traditional opinion that they are merely controlled by the valve openings. The pressure drops in these tubes are calculated by the proposed “common pressure pool with multiple outlets” (CPPMO) and the “common pressure pool” (CPP) methods. It is found that the local gas resistance dominates the pressure drop in the solid discharge tubes, while the gas frictional resistance determines the pressure drop in the solid feed tube. In addition, when the solid flow rate nearly tends to zero in the solid feed tube, the air lock forms. A solid flux equation is then given by considering both the air lock and the pressure drop factors in the cross-flow moving bed.