颗粒直径对吸附分离影响的数值模拟

基于Fluent的多孔介质模型，建立了变压吸附制氧发生器的立式填充床模型。采用用户自定义函数功能，以反映吸附传质、传热，并将多孔介质单相模型整合为更精确的气固两相耦合模型。在此基础上，模拟了吸附颗粒直径对气相压力、速度、床层压降以及氧气分离浓度、回收率等参数的影响情况。结果表明：床层压降随颗粒直径的增大而减小；床层对入口急流的抗穿透性能随颗粒直径的增大而减小；相同条件下，采用较小颗粒直径能够提高氧气分离浓度、回收率，原因在于小颗粒直径降低了床层内气体的流速，增加了吸附时间，促进了吸附的进行。

Numerical simulation of the particle diameter on adsorption and separation

A vertical packed bed model of pressure swing adsorption to produce oxygen was established based on the Fluent porous medium model. The porous medium model for single-phase was integrated to gas-solid two-phase coupling model in the User Defined Functions in order to achieve the mass and heat transfer of the adsorption process. The effects of particle diameter on gas pressure，velocity and bed pressure drop were discussed. The concentration and recovery of oxygen were analyzed as well. The analytic results showed that the bed pressure drop and the resistance to jet stream in inlet were decreasing with increasing of particle diameter. Under the same conditions，the concentration and recovery of oxygen could be increased if smaller particles were used. Small particles help to decrease the gas velocity and increase the gas residence in the bed，resulting in better adsorption and separation consequently.