The discrete element method(DEM)was used to simulate the dense gas-solid two-phase flow in a spouted bed riser pipe.The particle phase was based upon the Lagrange method

which considers the interaction between particle and gas phase

and the particle collision adopt the soft ball model.The gas phase was based upon eulerian method

using the standard k ε model to simulate the gas phase turbulent flow.Through analyzing the flow behavior of particle/gas phase

the distribution of dense particles was described.Thus

the influence of particle size on particle agglomeration characteristics was studied.The results indicated that when the particle size was small

a large scale agglomeration near the wall was observed

coupled with a bad-distributed particle flow.As the particle size increases

the agglomeration was improved considerably.When the particle size was 160μm

particles distributed well along the height direction

without agglomeration.The numerical simulation results agreed well with that obtained from the subregion method.