Study on counter-flow steam gasification characteristics of biochar with Fe2O3/CaO in-situ catalysis in fixed bed

•A process for preparing hydrogen-rich gas by Fe/Ca in-situ catalytic biochar fixed-bed counter-flow steam gasification is proposed.•The gasification intensity of the biochar loaded with CaO is 66.44% higher than that of the biochar without loading.•The hydrogen production yield of Fe2O3 loaded biochar at 850℃ was 13.25 % higher than that of unloaded biochar, which was 2.54L/g·C.•The intensity of counter-flow gasification at 900 ℃ is 60.89% higher than that of downdraft gasification. It is important to explore a relatively cheap and efficient biomass steam gasification process for the high-value utilization of biomass. Biochar was used as raw material for steam gasification, and the steam gasification of counter-flow biochar fixed bed was enhanced by the in-situ catalysis of Fe2O3 and CaO. By changing the steam flow rate and heating temperature, the operating characteristics of counter-flow gasification were explored and compared with updraft and downdraft gasification. The experimental results show that the addition of CaO in counter-flow gasification can improve the gasification intensity of biochar at lower temperature and steam flow rate. At 750 ℃, the biochar loaded with CaO at steam flow rate of 3.75 ml/min has a maximum heating temperature LHV of 11.49 MJ/Nm3. As the heating temperature increases, the hydrogen production yield gradually decreases. At temperature of 850 ℃ and steam flow rate of 3.75 ml/min, the gasification intensity of CaO loaded biochar was 66.44 % higher than that of unloaded biochar, and the gasification intensity was increased by 15.04 % by loading Fe2O3. However, the addition of Fe2O3 can improve the hydrogen production yield of biochar. At 850 ℃ gasification temperature, the hydrogen production yield is 23.25 % higher than that of biochar without catalysis.