Biomass conversion by treatment with acids and steam

Abstract Title: Biomass conversion by treatment with steam and gaseous liquid A method for converting a biomass raw material into fibre or chemical products comprising treating the biomass with gaseous acid as a reactant and then heating it with steam to a reaction temperature. The process only requires a low chemical charge and can employ hydrochloric acid， sulphur dioxide， sulphur trioxide， formic acid or acetic acid. There may be a lower temperature when the gaseous acid is being used compared to when the raw material is being steam heated. The raw material may be lignocelluloses or agricultural residues including forest residuals or waste wood. The material may be washed to separate the fibre from chemical products for further refining. The approach is designed to concentrate reactants within the biomass leading to quicker disintegration based on the escape of chemical ions from hot steam into cooler aqueous environments. It can be used for producing paper and packaging and chemicals such as ethanol， xylitol， acetic acids and lignin.