Optimization of hydrogen purification via vacuum pressure swing adsorption

Abstract

An experimental study was performed for hydrogen purification using the vacuum pressure swing adsorption (VPSA) process, commonly adopted in gas mixture separation using hollow fiber materials. This study aimed to examine the effects of the operating pressure and the H2 concentration in the H2/CO2 mixture on the H2 purity (HP) and H2 recovery (HR). A design of experiment (DoE) based on central composite design (CCD) was adopted to develop the response of the experimental domain and determine the optimal operating conditions of the process. The highest HP and HR obtained were close to 99.99 % and 72.39 %, respectively. However, the two responses, HP and HR, cannot reach the maximum values simultaneously in their response surfaces; one should compromise on the other. HP increased, but HR decreased as the operating pressure and H2 concentration increased. With the operating pressure of 1 kg∙ cm−2 and H2 concentration of 50 %, optimum HP and HR were found to be 99.17 % and 32.03 %, respectively. Analysis of variance (ANOVA) revealed that the built quadratic models consisting of the primary and interaction terms predicted the acceptable results for HP and HR based on p-values and R2. In addition, beyond the principle of a larger F-value and a p-value less than 0.05, the H2 concentration was identified as a more significant factor than the operating pressure.