SARS患者专用PSA制氧机变压吸附过程的数值模拟:计算结果及分析

Mathematical Simulation on the PSA Process of a Special Miniature Oxygen Concentrator for SARS Patients: Simulation Results and Analysis

数值模拟了吸附时间、吸附压力、进气量、吸附床高度等工艺参数对微型氧氮分离过程的影响,分析了氧含量沿吸附床的演变过程,结果表明:微型氧氮分离过程为一种短周期的变压吸附循环;吸附压力越高,吸附阶段结束时氧气浓度波锋面穿透吸附床的距离越长:进气量越大,要求吸附床高度越大:吸附床长度缩短会导致吸附阶段氧气浓度锋面穿透吸附床;从开始到循环达到稳定状态需要大约15个循环:要想获得较高纯度的产品气,必须保证氧气浓度波锋面前沿不移出吸附床;传质阻力对过程的影响非常大,不能近似认为是瞬时平衡过程。

The effects of adsorption duration, adsorption pressure, column length and feed flowrate on the presure swing adsorption (PSA) process of the miniature separation of oxygen and nitrogen were simulated mathematically. The evolvement of the profil of oxygen concentration along the column was predicted. The simulating results show that the miniature PSA process is a kind of short-time cycles, and the higher the adsorption pressure, the longer the shock profile of oxygen concentration passes through the column. With the increasing of feed flowrate, the length of the column must be extended. It is founded that a short column will cause a decrease in oxygen purity in product and the cyclic steady-state is achieved after about 15 cycles. If the high purity oxygen is expected, the shock profile must not pass through the adsorption column. The mass transfer has important influence on the performance of the miniature PSA process and the local equilibrium approximation can not be applied.