Green Hydrogen Production by Chemical Looping Reforming of Wheat Straw Pyrolysis Volatiles via LaNixFe1–xO3@SBA-15

Abstract

Using zero-carbon resource biomass with wide sources and abundant reserves as raw materials is of great significance for the sustainable development of energy and the environment to produce hydrogen with green and low carbon. In this study, a LaNi_xFe_1–xO₃@SBA-15 perovskite oxygen carrier with strong oxygen storage capacity and controllable lattice transport was prepared, which was used in the chemical looping reforming process of total components of wheat straw pyrolysis volatiles, and it is expected to realize the efficient production of green hydrogen. With volatile conversion, syngas selectivity, and H₂/CO as responses, orthogonal experiments were designed and carried out based on the multifactor response surface analysis method to analyze the interaction between factors. The results showed that Ni doping reduced the metal–oxygen bond’s binding energy and improved lattice oxygen’s mobility. LaNi_0.8Fe_0.2O₃@S was considered the best oxygen carrier, whose volatile conversion and syngas selectivity were 98.0 and 84.5% and the output of H₂ and syngas was 544.9 and 880.2 mL·g^–1, respectively. Multifactor response surface analysis showed that temperature was the key factor of volatile chemical looping reforming, and there was a strong interaction between the amount of oxygen carriers and space velocity. The optimum reaction conditions were 765 °C, 150 mL·min^–1·g^–1, and 0.82 g of oxygen carriers. The experimental verification showed that the volatile conversion rate was 98.0%, and the predicted value was 98.7%, and the predicted value was basically consistent with the experimental value. Ten cycles showed that LaNi_0.8Fe_0.2O₃@S had excellent reforming performance, the volatile conversion rate had good stability with a maximum fluctuation of less than 2%, the selectivity of syngas remained around 84%, and the CH₄ content remained within 2%. This study provided a certain experimental basis for the preparation of green hydrogen by chemical looping reforming of biomass pyrolysis volatiles.