Design And Optimization Of A New Type Distributor Of The Expanded Bed And The Analysis Of The Flow Field Distribution Within The Bed

As a new separation device, expanded bed adsorption is widely used in biochemical separation process, and the expanded bed distributor as an important component has a direct impact on the normal operation of the expanded bed adsorption. The design and optimization of its structure has been a concern in recent years. This paper presents a new type distributor of expanded bed, and numerical simulation of the flow field within the bed mounted upon the new type distributor is performed by CFD software. The liquid distribution performances of the new type distributor in the pilot-scale expanded bed are investigated, and different internal structures were simulated and optimized in the new type distributor.When optimize the operating conditions for the expanded bed mounted on the new type distributor in the simulation process, ICEM is used for software for modeling and meshing, and k-ε two-equation model and the porous-jump boundary conditions are adopted in FLUENT solver. Flow behaviors in cold model tests are consistent with results of numerical simulation. The increase of the liquid superficial velocity within the bed and the circulation ratio will improve the radial distribution effect of the distributor. When the circulation ratio increases gradually in an appropriate range, the size of vortex in the bottom region will be reduced and radial uniformity of the velocity in the expanded bed will be achieved.To optimize arrangements of holes on the jet nozzle, fluid distribution within expanded beds mounted on distributors installed with three different types of nozzle structure are stimulated at a fixed operating condition. By increasing the number of holes gradually on standard nozzle models, both orifice flow rate and jet suction volume can be reduced, which will improve the effect on fluid radial distribution of the new type distributor.In the premise of the same standard nozzle structure,4distribution disks with different cone angles are simulated under the same operating condition. The results reveal that a larger cone angle of the distribution disk within the distributor provides better fluid radial distribution.