快速变压吸附制氧动态传质系数模拟分析

Analysis of dynamic effective mass transfer coefficients of rapid pressure swing adsorption process for oxygen production

研究快速变压吸附制氧过程中的传质过程,结合实验数据对全局动态传质系数与常数传质系数进行对比模拟分析,并考察各传质阻力对传质效果的影响。结果表明:基于轴向、膜扩散和孔扩散估算的动态传质系数是有效的。膜阻力是主要阻力,其次是轴向扩散阻力,大孔扩散阻力较小,微孔扩散阻力可忽略。在快速变压吸附中,由于气速和温度变化较快,传质系数也会有较大变化,总体趋势是传质系数随着温度和气速的升高而升高。采用恒定传质系数无法准确描述吸附塔内各个时间点、空间点上的传质行为,根据各节点状态计算出的动态估算传质系数能够与吸附塔内的行为有较好的吻合度,模型具有较高的可信性。

The mass transfer process of RPSA（rapid pressure swing adsorption） and the effect of varions mass transfer resistances on mass transfer were investigated. The global dynamic mass transfer coefficient was compared with constant mass transfer coefficient. The results show that the dynamic mass transfer coefficients based on axial, membrane diffusion and pore diffusion estimation are effective. Membrane resistance takes up a large part of lumped resistance. Followed by axial diffusion resistance, the macrospores diffusion resistance and the micropores diffusion resistance can be neglected. In the rapid PSA, the mass transfer coefficient will change due to the rapid change of gas velocity and temperature, and the overall trend is that the mass transfer coefficient increases with the increase of temperature and gas velocity. Using the constant mass transfer coefficient cannot accurately describe the mass transfer behavior at each time point and space point in the absorber. The dynamic estimation mass transfer coefficient calculated according to the state of each node can have good coincidence with the behavior in the absorption bed, and the model has high reliability.