Effect of adsorption–desorption on hydrogen purity and recovery in non-adiabatic pressure swing mediated by microporous palm kernel shell adsorbent

Abstract

The adiabatic cylindrical columns, which are commonly used in the pressure swing adsorption (PSA), do not recuperate the heat energy effectively from the adsorption–desorption processes, resulting in energy waste to the surrounding and degradation of the PSA performance over time. In this work, a non-adiabatic PSA mediated by an amorphous microporous palm kernel shell activated carbon demonstrated effective CO2 capture and hydrogen purification from syngas surrogate. The hydrogen recovery was improved by delaying the adsorption through a non-adiabatic pressure swing, in which transfer of the heat was allowed between the two plate columns. The improved hydrogen recovery, however, was achieved at the expense of decreasing hydrogen purity. Hydrogen recovery of 98.7% and purity of 97.5% were obtained at 3 min of adsorption whereas, hydrogen recovery of 99.3% and purity of 92.5% were obtained at longer adsorption of 5 min. Although desorption during blowdown did not affect the purity and recovery of hydrogen significantly, it revealed a noticeable trade-off between carbon dioxide purity and recovery at increasing blowdown time. The non-adiabatic plate PSA is promising in improving the hydrogen recovery that might be challenging using the conventional adiabatic cylindrical column PSA.