Biomass Chemical Looping Gasification Performance of a Ce-Modified BaFe2O4 Oxygen Carrier

In this study, Ce-modified BaFe2O4 preparedby the sol-gel method was subjected to batch gasification experimentsin a fixed bed. The effects of temperature (T), steam-to-biomassratio (S/B), oxygen supply coefficient (alpha), and Ce loading onthe gasification performance were explored. The optimal oxygen carrierwas selected as 6 wt % BaFe2O4 (6Ce-BF). Excellentgasification performance was achieved at T = 850 degrees C, S/B = 3, and alpha = 0.25, where the syngas yield was 1.735Nm(3)/kg center dot biomass, the carbon conversion was 93.35%,the gasification efficiency was 95.55%, and the cycle stability wastested under these conditions. Fresh and recycled oxygen carrierswere characterized by X-ray diffraction (XRD), H-2-temperature-programmedreduction (TPR), X-ray photoelectron spectroscopy (XPS), scanningelectron microscopy (SEM), and Brunauer-Emmett-Teller(BET) techniques. The results showed that the addition of Ce effectivelyimproved the relevant performance parameters of BaFe2O4 and enhanced its cycle stability. The formation of CeO2 strengthened the oxidation of the oxygen carrier at mediumtemperature and optimized the oxygen release at high temperature.The XRD results show that the loading of Ce facilitates the crystallizationprocess of BaFe2O4. And the XPS results indicatedthat 6Ce-BF possessed more oxygen vacancies and stronger oxygen transportcapacity after cycles.