Renewable hydrogen production from biogas using iron-based chemical looping technology.

[Display omitted] • Biogas was used as the reactant for low-carbon H 2 generation. • A tailored syngas ratio of 1:1 can be produced by adjusting CO 2 amount. • CO 2 could inhibit carbon deposition effectively in Fe 3 O 4 -Fe 0.947 O stage. • The behavior of CO breakthrough at different temperature was investigated. • The proposed multi-reactor model can improve the efficiency of H 2 production. An integrated recycling waste bioenergy and manufacturing low-carbon hydrogen by a method to convert biogas to hydrogen based on the chemical looping concepts was proposed in this study. Biogas from biomass anaerobic digestion and pyrolysis was employed in the reduction step as the feedstock of fuel gas. Simulated marsh gas (CH 4 and CO 2) and pyrolysis gas (CO and H 2) were used to validate the feasibility of the reduction performance with iron (III) oxide at different reaction temperatures. The experiments were conducted by using a thermogravimetric analyzer and a tandem packed-bed reactor. As for marsh gas, the reaction behavior was completely different under different CO 2 concentrations and converting temperatures. The reduction reaction with CH 4 would be divided into three stages, including complete combustion, competition reaction, and partial oxidation stage. Furthermore, the syngas with a tailored ratio of 1:1 can be produced without CH 4 breakthrough by adjusting CO 2 concentration. Besides, the total H 2 production achieved 241.9 mL per gram of oxygen carrier with a purity of 98.29%. Regarding the pyrolysis gas, the solid conversion and CO breakthrough curve were investigated. Compared to a single reactor, seven reactors were required to increase the average solid conversion from 34.1% to 42% and reduced the total redox time from 705.6 min to 437.7 min. Overall, this study provided a link between waste bioenergy recycling and H 2 generation with a novel chemical looping hydrogen generation (CLHG) system and supplied theoretical support for scaling up the packed-bed reactor to improve H 2 production efficiency. [ABSTRACT FROM AUTHOR]