Distinctive Effects of CaO Additive on Atmospheric Gasification of Biomass at Different Temperatures

Calcium oxide has long been recognized as an effective in-bed catalyst for reforming or cracking tars generated in thermally decomposing hydrocarbon fuels such as biomass. Under pressures as high as 20 atm, the oxide was also widely tested as a good CO2 acceptor to capture CO2 on-site to produce high-caloric pipeline gas from gasifying coal and coal-coke. By using CaO as an additive of the fuel and bed material, the research detailed in this research note demonstrated that CaO could also be a substantially good CO2 acceptor for the atmospheric gasification of biomass, provided the reaction temperature is appropriately low, such as not much over 973 K. At temperatures >1073 K, the additive exhibited basically the catalytic effect only, which led the H2 content of the product gas to increase and the tar release with the gas to decrease.