Experimental Simulation of Rapid Pressure Swing Adsorption for Medical Oxygen Concentrator and Numerical Simulation of the Critical Desorption-by-Purge Step

As efforts are sought to achieve an overall compact and lightweight medical oxygen concentrator (MOC), rapid pressure swing adsorption (RPSA) plays an important role to lower the bed size factor (BSF). A mini experimental system supported by switching control and data acquisition was built to simulate a Skarstrom-like RPSA cycle. It was experimentally demonstrated that BSF cannot be indefinitely reduced by lowering total cycle time (tc ) and adsorbent particle size (dp). However, an optimum process performance of BSF = 25--50 lbs/TPD c with an O2 recovery (R) = 25--35% for production of ∼ 90% O2 could be achieved using a dry, CO2-free air feed at adsorption pressure (PA) of 3--4 atm, dp of ∼ 350 &mgr;m, and tc of 3--5 seconds.;A rigorous mathematical model using finite volume method with Superbee flux limiter was developed and solved by numerical method of line (MOL) and Matlab's ode solver to simulate the critical O2 back-purge step of a RPSA cycle. Finite adsorption kinetics, column pressure drop, and non-isothermality are the primary impediments to efficient purge in RPSA MOC of this study, while the effects of gas-phase mass and thermal axial dispersions and gas-solid heat transfer resistance are negligible. Very short purge time and small dp in pancake adsorber is not practical. dp of 300--500 &mgr;m yields optimum purge efficiency for bed size reduction of MOC.;This dissertation is written in three major parts with Chapter 1 the introduction, Chapters 2 to 4 the experimental work, and Chapters 5 to 7 the model simulation work; major research findings are reported in Chapters 4 and 7.