Researchers in Spain are proposing 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.
A paper on their work was published online 12 August in the ACS journal Environmental Science & Technology.
We outline here a new process for H2 production and/or power generation from natural gas, with inherent CO2 capture combining the known benefits in terms of energy efficiencies of sorption enhanced reforming processes and chemical looping processes. The objective of this conceptual paper is to demonstrate the theoretical viability of the new process by incorporating state of the art knowledge on the thermodynamics and kinetics of the main gas-solid reactions involved. Some design and operational challenges are also outlined for future R&D work on this process.—Abanades et al.
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.
J. C. Abanades, R. Murillo, J. R. Fernandez, G. Grasa and I. Martínez (2010) New CO2 Capture Process for Hydrogen Production Combining Ca and Cu Chemical Loops. Environ. Sci. Technol., Article ASAP doi: 10.1021/es101707t