Efficient and cost-effective production of clean energy carriers such as hydrogen is of critical importance for sustained growth of the modern economy. Among the various approaches for sustainable hydrogen generation, solar-thermal water-splitting represents a potentially attractive and environmentally friendly option. Typical solar-thermal water-splitting schemes involve cyclic redox reactions of transition metal oxides to indirectly convert solar energy and water into separate streams of hydrogen and oxygen. In its simplest configuration, a solar-thermal water-splitting cycle involves two redox steps. In the first step, solar energy is used to decompose a metal oxide at high temperature. In the subsequent step, the decomposed metal/metal oxide is reoxidized with water, producing hydrogen. The key for the aforementioned process is the metal oxide decomposition step. To date, the endothermic decomposition reaction for most, if not all, solar-thermal water-splitting processes are conducted at temperatures above 1300 �C. Therefore, novel solar-thermal schemes that can effectively promote metal oxide reduction at lower temperatures are highly desired in order to achieve improved efficiency and economic attractiveness for solar-thermal hydrogen generation.The current study investigates a cyclic redox process for cogeneration of liquid fuels and hydrogen using methane and solar energy. Fe3O4/Fe redox couple is used for methane (partial) oxidation and water-splitting. In this process, syngas from methane oxidation is used in a Fischer-Tropsch synthesis process for liquid fuel synthesis whereas H2 from water-splitting is processed as a co-product. The current study reports the redox performances of a novel lanthanum strontium ferrite (LSF) supported iron oxide in a lab-scale tubular reactor. Nearly 100% conversion of methane is achieved in the iron oxide reduction step. Steam to hydrogen conversion in excess of 60% is also observed. Results from experimental studies and/or thermodynamic analyses are then used in Aspen Plus� simulation models to evaluate the proposed process scheme.

Hydrogen and liquid fuel co-generation via a cyclic redox scheme

248th National Meeting (2014)

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