Syngas production from chemical looping gasification of rice husk-derived biochar using BaFe2O4 as an oxygen carrier

Abstract

Chemical Looping Gasification (CLG) is a promising technology for producing syngas with several merits. In this work, BaFe2O4 has been prepared via a sol-gel method as an iron-based composite oxygen carrier, and it was used to produce syngas from CLG of rice husk-derived biochar. At first, the effect of oxygen carrier (OC) content in the mixture sample of biochar and OC has investigated by a thermogravimetric analyzer (TGA). The results revealed that the highest weight loss rate was obtained when the OC content attained 60%, indicating it achieved the highest gasification reactivity. The effect of different conditions (temperature, reaction time, N2 carrier flow rate, and OC content) on syngas production from CLG of biochar was evaluated using a fixed bed reactor as the main objective of this study. The maximum syngas yield was 0.0182 mol/g with H2/CO ratio of 0.39, which has obtained at a temperature of 900 °C, N2 flow rate of 50 ml/min, a reaction time of 60 min, and OC content of 60%. Adding steam for CLG of biochar has significantly enhanced syngas yield and H2/CO ratio to 0.0778 mol/g and 3.2, respectively (at a steam flow of 0.055 ml/min). This indicates that the H2/CO ratio can be flexibly set to meet the requirement of syngas applications by controlling the steam addition rate. Moreover, the characterization of BaFe2O4 was investigated using XRD, SEM, H2-TPR, and BET, as the results have obviously confirmed the sintering of regenerated OC.