Experimental and Computational Investigation of Gas Separation in Adsorbent-coated Microchannels

Abstract

An experimental and computational investigation of gas separation in adsorbent-coated microchannels is performed. Experiments on porous-layer-open-tubular (PLOT) columns containing zeolite 5A using a ternary mixture of helium (He), nitrogen (N2) and carbon dioxide (CO2) show sequential breakthrough of N2 and CO2 and gradual saturation of adsorption sites with trace water. Multiple tests conducted for the adsorbent breakthrough investigation result in determination of adsorbent layer properties. The heat and mass transfer model results for a pressure drop range of 5–55kPa and channel lengths from 1 to 4m are found to be in reasonable agreement with the data with an average absolute deviation (AAD) of 14% for adsorption time and 41% for temperature rise (ΔT). The larger error in ΔT is thought to be due to uneven adsorbent loading of the PLOT columns. Therefore, the adsorption experiments are also conducted with custom-made adsorbent-coated microchannels with known adsorbent mass and layer thickness. The AADs for adsorption time and ΔT then decrease to 4% and 25%, respectively, indicating that the overall gas separation process is described well by the adsorption stage models, with local variation due to fabrication variability.