Syngas production by chemical-looping gasification of wheat straw with Fe-based oxygen carrier

The iron-based oxygen carriers (OC's), Fe2O3/support (Al2O3, TiO2, SiO2 and ZrO2), for chemical looping gasification of wheat straw were prepared using impregnation method. The surface morphology, crystal structure, carbon deposition potential, lattice oxygen activity and selectivity of the yielded OCs were examined. The Fe2O3/Al2O3 OCs at 60% loading has the highest H2 yield, H2/CO ratio, gas yield, and carbon conversion amongst the tested OC's. Parametric studies revealed that an optimal loading Fe2O3 of 60%, steam-to-biomass ratio of 0.8 and oxygen carrier-to-biomass ratio of 1.0 led to the maximum H2/CO ratio, gas yield, H2 + CO ratio, and carbon conversion from the gasified wheat straw. High temperature, up to 950 °C, enhanced the gasification performance. A kinetic network interpreted the noted experimental results. The lattice oxygen provided by the prepared Fe2O3/Al2O3 oxygen carriers promotes chemical looping gasification efficiencies from wheat straw.