Application of hydrogen selective membranes to IGCC

This study considers the integration of Pd-based H₂-selective membranes in integrated gasifier combined cycles (IGCC) from both technical and economical point of view. The selected gasification system is based on Shell technology. Two different dry feeding systems are investigated: The first is a state-of-theart nitrogen-based lock hopper charger while the second uses CO ₂ as pressurization gas. The net electric efficiency of the two plants is evaluated as a function of the hydrogen recovery factor (HRF) and the membrane feed pressure in order to minimize the membrane surface area. 90% HRF and 54 bar feed pressure are the best operating parameters which correspond to a net electric efficiency of 39% both for N₂ and CO₂ feeding system. The cost of CO₂ avoided is calculated as a function of a parameter named MI which represents the membrane development in terms of performances and costs. Results show that an improvement of membrane technology is necessary to match the state-of-the-art CO₂ capture plant, even though membranes show good potentiality for cost abatement.