A hybrid solar-redox scheme for liquid fuel and hydrogen coproduction

The feasibility of a hybrid solar-redox process, which converts solar energy and methane into separate streams of liquid fuels and hydrogen through the assistance of an oxygen carrier, is investigated via both experiments and simulations. Fixed and fluidized-bed experiments are conducted to evaluate the redox performances of an oxygen carrier composed of iron oxide promoted with a mixed ionic-electronic conductor (MIEC) support. Over 95% conversion in the methane oxidation step and 60% steam to hydrogen conversion in the water-splitting step are observed. Aspen Plus (R) simulation based on experimental data and a comprehensive set of assumptions estimates the overall process efficiency to be 64.2-65.3% on a higher heating value (HHV) basis. Through the integration of solar energy, methane to fuel conversion efficiency can approach 100%. The proposed process has the potential to produce transportation fuels and hydrogen at high efficiency with reduced carbon footprint.