The design equations were compared with experimental results. Solid phase velocity estimated with the force balance equation is effective for improving the accuracy of pressure drop prediction even though the drag force of the solid phase was estimated based on the single particle terminal velocity. Because the contribution of the pressure drop at the exit of the feed tank is usually significant, a special emphasis was put on the region of particle acceleration in deriving the pressure drop estimation. (C) 2012 Elsevier B.V. All rights reserved.