Pressure-Swing Adsorption Process for Producing Fuel Cell-Grade Hydrogen from Steam Methane Reforming Gas

Hydrogen energy is acknowledged as being the cleanest energy source. As hydrogen fuel cell technology advances, the development of low-cost, high-quality hydrogen purification technologies has grown increasingly critical. Targeting the separation of steam methane reforming gas mixture with a typical composition of H2/CO2/CH4/CO = 76%/20%/3.5%/0.5%, a 6-bed-13-step pressure-swing adsorption process featuring four pressure-equalization steps was designed, in which a multi-layer adsorbent packing strategy was adopted to investigate the purification performance. The effects of feed flow rate, adsorbent packing combination, and purge-to-feed ratio on hydrogen purity and recovery, and on the impurity content level were analyzed. Furthermore, the gas-phase and solid-phase concentration distributions of each adsorbent layer under cyclic steady state were studied in detail, and the variation characteristics of their adsorption–desorption behaviors were systematically elaborated. Eventually, the optimal adsorbent combination and process condition configurations were determined. The results show that the proposed process can achieve a hydrogen purity of 99.99971%, with a concentration of CO of less than 0.2 ppm, which meets the fuel cell-grade hydrogen standard.