Techno-economic assessment of CO₂ capture in a decentralized H₂ production plant

Hydrogen is increasingly recognized as a key energy carrier for the transition toward a low-carbon economy. Coupling hydrogen production with carbon capture and storage (CCS) technologies is essential to reduce greenhouse gas emissions, especially when hydrogen is produced from carbon-based sources. This thesis presents a techno-economic comparison between Pressure Swing Adsorption (PSA) and membrane separation technologies for CO₂ capture from a pre-combustion hydrogen stream. The hydrogen is generated through an electrically assisted steam methane reforming (e-SMR) process using biogas, developed by the company SYPOX. The stream analysed originates from the tail gas of a first PSA unit dedicated to hydrogen recovery and consists of 3.88 kmol/h of gas with a CO₂ molar fraction of approximately 0.7. For the CO₂ capture PSA, a dynamic simulation model based on partial differential equations (PDEs) was developed in MATLAB, considering vacuum operation (VSA) and using zeolite 13X as the adsorbent material. For the membrane process, steady-state calculations were performed, employing a polymeric membrane made of PEBAX, also operating under vacuum conditions. Both technologies were assessed in terms of technical performance — including CO₂ removal efficiency, hydrogen recovery, and energy demand — as well as economic factors such as capital (CAPEX) and operating (OPEX) expenditures. The analysis highlights the trade-offs between performance and cost, providing insights into the selection of an optimal CO₂ capture technology for renewable hydrogen production systems.