Hydrogen Purification by Pressure Swing Adsorption: High-Pressure PSA Performance in Recovery from Seasonal Storage

Abstract

Hydrogen storage in a depleted gas field is a promising solution to the seasonal storage of renewable energy, a key question in Europe’s green transition. The gas composition and pressure in the month-long storage and recovery phase can vary substantially; meanwhile, the recovered H2 has to be pure, especially for fuel cell applications. Pressure swing adsorption can be used for the purification of the recovered gas. A lab-scale, four-bed PSA unit was built to investigate its applicability by separating different H2-CH4 mixtures. The feed parameters in the experiments are based on a depleted gas reservoir with a pressure range of 25–60 bar and methane contamination between 0 and 35%. The change in the feed properties is modeled by four distinct stages and the twelve-step cycle is tailored to each stage. The high pressure did not have any irreversible effects on the process. A hydrogen purity of 99.95% was achieved in all stages with the average hydrogen recovery ranging from 60 to 80%. The experiments revealed the challenges of a cycle design when the feed parameters are not constant, but an adequate separation performance was shown, which supports the applicability of the PSA in seasonal storage and confirms the need for further investigation with multicomponent contaminants and large-scale projects.