Heat‐exchange pressure swing adsorption process for hydrogen separation

A current focus in the energy field is on the use of hydrogen in fuel cells. Development of a hydrogen station system is important to the commercialization of fuel cells and fuel cell powered vehicles. In this study, the heat‐exchange pressure swing adsorption (HE‐PSA) was developed to design a compact H 2 PSA process for small spatial occupancy in the hydrogen station. The adsorption dynamics and performance of the newly designed bed were compared with those of a conventional bed by using a quaternary mixture (H 2 /CO 2 /CH 4 /CO 69:26:3:2 vol %) which is generally obtained from the steam‐reforming reaction of natural gas. Because the detrimental exothermic/endothermic heat effects accompanied by the adsorption/desorption steps were reduced by heat exchange between the adsorption beds, the separation performance of the HE‐PSA was higher than that of a conventional PSA. In addition, the spatial occupancy of the beds could be significantly reduced, compared with a conventional PSA, because the single annular‐type bed performed the function of two beds in the HE‐PSA. © 2008 American Institute of Chemical Engineers AIChE J, 2008