(143b) Kinetic Process Assessment of H2 Purification over Highly Porous Carbon Sorbents Under Multicomponent Feed Conditions

As a universal energy career, the need for pure H₂ is ever increasing due to its ubiquitous role in petrochemical refining, metal reduction, and the up-and-coming fuel cell market. Hydrogen produced from steam methane reforming (SMR) is typically laden with impurities such as CO₂, CO, and CH₄. A full assessment of the efficacy of potential sorbents for H₂ purification requires a thorough evaluation of thermodynamic and kinetic behaviors associated with multicomponent H₂ upgrading by pressure swing adsorption (PSA). As such, in this study we assessed three commercially available activated carbons with high surface area and pore volume for the PSA upgrading of H₂ from simulated SMR off-gas stream consisting of H₂/CO/CH₄/CO₂ (75/5//5/15 vol%). In addition to high-pressure adsorption isotherms for pure gases, H₂ purity, recovery, and productivity were estimated from PSA runs, while actual (CO+CH₄ +CO₂)/H₂ selectivity values were estimated from breakthrough experiments. For the best performing material, the results demonstrated H₂ purity and recovery of 99.7 and 65%, respectively with a productivity of 20.85 mol_H2/kg.h and actual (CO+CH₄ +CO₂)/H₂ selectivity of 73. Moreover, the affinity of the different adsorbates toward the activated carbons presented from the most adsorbed to the least adsorbed gas was in the order of CO₂ > CH₄ > CO >> H₂.