PSA制氧过程产品气流量对其氧气体积分数的影响

为了提高小型两床变压吸附（PSA）制氧机在变产品气流量下的氧气体积分数，建立了改进的Skarstrom两床循环PSA制氧实验装置，研究了产品气流量对其氧气体积分数的影响。研究结果表明，在低产品气流量运行条件下，通过提高清洗气总氧量与原料气总氧量之比（P/F）以及降低最高吸附压力与最低解吸压力之比（θ）可消除氧气返混的不利影响；在高产品气流量运行条件下，通过提高P/F和θ可以提高实验装置中分子筛的工作能力，进而提高产品气中的氧气体积分数。在此基础上，对低和高产品气流量运行条件下的P/F和θ进行了调节，分别将产品气流量为3.55 L·min?1和19.88 L·min?1时的氧气体积分数从92.4%增加至了95.7%和从74.0%增加至了74.9%。本文的研究结果可为变产品气流量下PSA制氧工艺参数优化提供参考。 

Influence of product flow rate on O2 volume fraction in PSA oxygen generation process

In recent decades, the small-scale pressure swing adsorption (PSA) oxygen generator has been widely used in the fields of home medical and hospital oxygen supply, anoxic environments, and plateau environments due to its cost effectiveness, operational flexibility, and adequate O₂ volume fraction. The flexible optimization of PSA oxygen generation in response to changes in product demand is an important factor in its practical performance. To study the influence of a variable product flow rate on O₂ volume fraction in the small-scale PSA oxygen generator, experimental equipment was set up, which consisted of a modified Skarstrom-cycle two-bed PSA system. The research results show that variations in the parameters at the lower product flow rate (≤10.37 L·min?1) may have a negative effect on oxygen countercurrent mixing, which can impair oxygen generation, and at higher product flow rates (≥13.57 L·min?1) may cause the negative effect of nitrogen breakthrough, which decreases the working capacity of the adsorbents in the bed. The O₂ volume fraction at the lower product flow rate was improved by increasing the ratio of total oxygen in the purge gas to the total oxygen in the feed gas (P/F) and by decreasing the ratio of the highest adsorption pressure to the lowest desorption pressure (θ) during a cycle to suppress oxygen countercurrent mixing. The O₂ volume fraction at the higher product flow rate was improved by increasing the P/F and θ values to improve the working capacity of the adsorbents in the bed. Accordingly, adjustments are made in the P/F and θ values at the lower and higher product flow rates to achieve optimal oxygen generation performances, enhancing the O₂ volume fraction from 92.4% and 74.0% to 95.7% and 74.9% at the respective product flow rates of 3.55 L·min?1 and 19.88 L·min?1. This work is meaningful for the optimization of the parameters of the PSA oxygen production process at variable product flow rates.