Adsorption in the context of clean hydrogen production: process intensification by integrating H2 purification and CO2 capture - A modeling and experimental study of multi-component adsorption

Abstract

Coupling fossil-based H2 production with carbon capture and storage can produce H2 with low associated CO2 emissions, which is urgently needed to decarbonize industry, the energy sector, and the transportation sector. Vacuum pressure swing adsorption (VPSA) allows for the integration of two key separation tasks in this process, H2 purification and CO2 capture. In this work, we compare experimental and simulation results of a cyclic VPSA process. Our focus is the evaluation of different approaches for modeling multi-component adsorption. In particular, we use a three process Langmuir model for CO2 adsorption and Langmuir model for H2 and CH4 adsorption. We assess the different options for energetic site matching. The results indicate that energetic site matching of H2 and CO2 is of little importance. In contrast to that, only two models with a different energetic site matching for CO2 and CH4 result in a reasonable prediction of the experimental results, i.e. uncorrelated (UC) and uncorrelated unselective B (UCUS B). Both extended Sips isotherms and the use of the real adsorbed solution theory (RAST), however, result in a better prediction of the experimental results.