Experiments and simulations of gas-solid flow in an airlift loop reactor

The hydrodynamics in a gas-solid airlift loop reactor was investigated systematically using experimental measurements and CFD simulation.In the experiments,the time averaged parameters,such as solid fraction and particle velocity,were measured by optical fiber probe.In the simulation,the modified Gidaspow drag model accounting for the interparticles clustering was incorporated into the Eulerian-Eulerian CFD model with particulate-phase kinetic theory.Predicted values of solid fraction and particle velocity were compared with experimental results,validating the drag model and the simulation.The results show that the profiles of particle velocity and solid fraction are uniform in annulus.However,the core-annulus structure appears in other three regions (draft tube region,bottom region and particle diffluence region),which presents the similar heterogeneous feature of aggregative fluidization usually occurred in normal fluidized beds.Simulated profiles of particle residence time distribution indicate that the airlift loop reactor should be characterized by near perfect mixing.