Adsorption Based Portable Oxygen Concentrator for Personal Medical Applications

Abstract

The potential of a two-step, single bed pulsed pressure swing adsorption process (PPSA) oxygen concentrator has been investigated for portable personal use by chronic obstructive pulmonary disease (COPD) patients. A mathematical model of the process was first developed and the process was simulated using COMSOL Multiphysics software. A principal conclusion from the theoretical study is adsorber size decreases with decreasing adsorbent particle size and increasing cycling frequency. A graphical design methodology has been proposed based on the simulation results.

Guided by simulation results and response times of available sensors and controllers, an experimental set-up consisting of a 10 cm bed packed with 63-75 µm 5A zeolite particles was custom-designed to verify model assumptions. Pressure drop experiments with helium, and breakthrough experiments with oxygen and air revealed increased pressure drop and axial dispersion for the chosen particle size due to non-uniform bed voidage from clustering. This resulted in significant performance deterioration in PPSA experiments. After correcting for the deviations, the simulation model adequately captured the experimental PPSA results, which gave confidence that the reasons for performance deterioration were correctly identified. Potential solutions to the problems arising from clustering of very fine particles have been discussed.