Experimental study of dual fixed bed biochar-catalytic gasification with simultaneous feed of O2-steam-CO2 for synthesis gas or hydrogen production

The catalytic gasification of biochar was investigated in the presence of a Ni/SiO₂ catalyst in a fixed bed reactor with an O₂-steam-CO₂ gas feed. The effects of operating temperature, catalyst nickel loading and composition of O₂-steam-CO₂ feed gas on biochar carbon conversion and gas products were investigated. The results indicate that the highest biochar carbon conversion could be obtained at approximately 800 °C, whilst the 10% Ni/SiO₂ catalyst was shown to produce the greatest syngas yields. The presence of O₂ in the feed gas can result in slightly more CO in the gas product, whilst a higher steam content leads to more H₂ in the gas product. The CO₂ offered a benefit as an adjusting agent for achieving a desired H₂/CO ratio. No evidence of coke deposition on the catalyst was found under any of the tested conditions.