Experimental Study of Chemical-Looping Reforming in a Fixed-Bed Reactor: Performance Investigation of Different Oxygen Carriers on Al2O3 and TiO2 Support
2014
Karimi, E. | Forutan, H. R. | Saidi, M. | Rahimpour, M. R. | Shariati, A.
This study examines the hydrogen production by the steam reforming of methane integrated to chemical-looping reforming (CLR) as a novel technology in a fixed-bed reactor at 700–1200 °C. The particles are present in two consecutive oxidation and reduction steps. In the reduction step, the oxygen carrier is reduced with the fuel, which, in turn, is partially oxidized to H₂ and CO (synthesis gas), and in the oxidation step, the reduced oxygen carrier is reoxidized with oxygen (O₂ + argon). The oxygen carriers Fe, Mn, Co, and Cu using inert materials Al₂O₃ and TiO₂ as a support are prepared by the precipitation method. The samples are analyzed using energy-dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), and X-ray diffraction (XRD) to check the carrier specifications before and after the process. The main goal of this study is investigation of the reactivity of different metal oxides on Al₂O₃ and TiO₂ support. The conversion of fuel into products depends upon the type of oxygen carriers and experimental conditions. All of the oxygen carriers show favorable hydrogen production over the 3 cycle experiments at optimum temperature. Among used metals, Fe has the highest hydrogen yield. The optimum temperature for maximum conversion of methane over Fe-, Mn-, Co-, and Cu-based carriers is nearly 1025, 1030, 900, and 800 °C, respectively. According to experimental results, at higher temperatures, Fe- and Mn-based carriers have better performance, but at lower temperatures, the Cu-based carrier is more efficient compared to other carriers. The comparison of supports represents that the reactivity of Al₂O₃ is better than TiO₂, so that the conversion of the fuel over Fe/Al₂O₃ is 95–100% in comparison to Fe/TiO₂, which is 78–80%.
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