Adiabaticity impact on hydrogen purification and recovery by pressure swing from binary mixture containing hydrogen and carbon dioxide

Abstract

Hydrogen purification by conventional adiabatic cylindrical column and non-adiabatic plate pressure swing adsorption (NAPSA) mediated by amorphous spent coffee grounds was investigated to study the impact of the two systems on hydrogen purity and recovery from methane reforming product. The proposed NAPSA design addresses the limitations of conventional columns, namely their low recovery and dissipated adsorption heat. By recapturing the dissipated adsorption heat, the NAPSA design facilitates the regeneration and recovery of the process. This innovative approach mitigates the challenges associated with conventional column designs, allowing for improved efficiency in the regeneration and recovery stages. Both systems yielded high hydrogen purity of 99.99%, attributed to the favorable characteristics of the adsorbent. Characterization of the spent coffee sample showed that the sample exhibited some forms of layered structure embedded with calcium and carbonate ions within the structure. Despite better mass transfer in the conventional adiabatic system, the non-adiabatic plate PSA system was capable of retaining carbon dioxide in the adsorbent bed longer due to better heat dissipation. As a result, the non-adiabatic PSA system improved the hydrogen recovery by 5.2%. Extended carbon dioxide retention time and good heat transfer management were found important in resolving the inherent trade-off issue between the purity and recovery that exists in the present gas purification system.

Keywords

• Hydrogen
• Fuel
• non-adiabatic PSA
• Carbon capture
• Purification
• Binary gas mixture