Abstract：Suspension of the catalyst particles was studied in a jet loop reactor with computational fluid dynamics method. A 2-dimensional axisymmetry model was adopted with Reynolds Stress Model(RSM) to analyse the effect on the flow rate ratio (RQ) of circulation to jet from the diameter ratio of draft tube to reactor (De/D), geometric structure of the reactor, axial distance of the nozzle and the draft tube (Hn). Then the Discrete Phase Model was used to describe particle suspension against various bottom type，jet velocity and diameter of particles. Conclusions can be drawn from the simulation results: RQ is largest when De/D is 0.67 and the deviation of RQ is below 3.6% when bottom type and Hn vary. With cone bottom and lower Hn, particle suspension can be smoothly achieved. With the specified geometric parameters of the equipment and physical property of the two phases, the critical jet velocity(Vnc) that can suspend particles，of low concentration by volume（about 0.1%），in the whole device is obtained through numerical prediction and correlation of Vnc and catalyst particle size is suggested from numerical results.
