Impact of Hemicelluloses Pre-extraction on Pulp Properties of Sugarcane Bagasse

The extraction of hemicelluloses, which otherwise would be wasted in the black liquor, can be integrated with chemical pulping processes in a biorefinery approach that will generate a sugar-rich feedstock for production of fuels and chemicals. Extractions of hemicelluloses from sugarcane bagasse under dilute sulphuric acid or mild alkaline conditions were performed, using a central composite experimental design. Selected solid residues obtained after dilute acid, hot water (zero acid) or mild alkaline pre-extractions were subjected to soda or soda-AQ pulping, and kraft pulping of the dilute acid pre-extracted solid residue was also performed. The integration of hemicelluloses preextraction by alkaline methods into a soda-AQ-based pulping process was preferred for sugarcane bagasse as feedstock, since it enabled xylan recovery of 69.1%, while providing pulps with superior tear strength and brightness.