CO2 valorisation based on Fe3O4/FeO thermochemical redox reactions using concentrated solar energy. (2nd February 2012)

• Record Type: Journal Article
• Authors: Abanades, Stéphane; Villafan‐Vidales, Isabel
• Is Part Of: International journal of energy research. Volume 37:Number 6(2013:May)
• Page Start: 598
• Page End: 608
• Publication Date: 2012-02-02
• Subjects: Power resources -- Periodicals; Power (Mechanics) -- Periodicals; Power resources -- Research -- Periodicals; 621.042
• DOI: 10.1002/er.1953
• Languages: English
• ISSNs: 0363-907X

Abstract

<abstract abstract-type="main"> <title>SUMMARY</title> <p>The solar‐driven dissociation of CO<sub>2</sub> by thermochemical looping via Fe<sub>3</sub>O<sub>4</sub>/FeO redox reactions is considered. The process recycles and upgrades CO<sub>2</sub> to ultimately produce chemical synthetic fuels from high‐temperature solar heat and abundant feedstock as only inputs. The two‐step process encompasses the endothermic reduction of Fe<sub>3</sub>O<sub>4</sub> to FeO and O<sub>2</sub> using concentrated solar energy as the high‐temperature source for reaction enthalpy and the nonsolar exothermic oxidation of FeO with CO<sub>2</sub> to generate CO. The resulting Fe<sub>3</sub>O<sub>4</sub> is then recycled to the first step and carbon monoxide can be further processed to syngas and serve as the building block to synthesise various synfuels by catalytic processes. This study examines the thermodynamics and kinetics of the pertinent reactions. The high‐temperature thermal reduction of Fe<sub>3</sub>O<sub>4</sub> is realised above the oxide melting point by using concentrated solar thermal power. The reactivity of the synthesised FeO‐rich material with CO<sub>2</sub> at moderate temperature is then investigated by thermogravimetry. FeO conversion higher than 90% can be achieved with reaction rates depending on temperature, particle size and CO<sub>2</sub> concentration. The solar‐produced nonstoichiometric FeO is more reactive with CO<sub>2</sub> than commercial pure FeO. Activation energies of 57 and 68 kJ/mol are derived from a kinetic analysis of the CO<sub>2</sub>‐splitting reaction in the range of 600 °C to 800 °C with solar and commercial FeO, respectively. Copyright © 2012 John Wiley & Sons, Ltd.</p> </abstract>