New CO2 Capture Process for Hydrogen Production Combining Ca and Cu Chemical Loops

This paper presents a new solids looping process for capturing CO2 while generating hydrogen and/or electricity from natural gas. The process is based on the sorption enhanced reforming of CH4, employing CaO as a high temperature CO2 sorbent, combined with a second chemical loop of CuO/Cu. The exothermic reduction of CuO with CH4 is used to obtain the heat necessary for the decomposition of the CaCO3 formed in the reforming step. The main part of the process is completed by the oxidation of Cu to CuO, which is carried out with air diluted with a product gas recycle of this reactor at sufficiently low temperatures and high pressures to avoid the decomposition of a substantial fraction of CaCO3.