Forest Biomass and Paper Industry, a Pathway to Green Biofuels

The components of wood, celluloses, hemicelluloses and lignin, can be separated and converted into new non paper products. This paper treats the specific case of lignin and hemicellulose extraction from a Kraft pulping process. Two processes have been investigated for the extraction of lignin from black liquor. One is an enhanced version of precipitation of lignin under low pH conditions achieved by carbonation of Kraft black liquor. The second process focuses on the acidification of the black liquor by electrodialysis with a bipolar membrane. This process produces clean lignin and valuable caustic soda. The extraction of hemicelluloses from wood chips and their partitioning into a mixture of C5 and C6 sugars can be accomplished by a two-step hydrolysis. The sugars can then be converted into a large number of derivatives. The case of fermentation into butanol is presented. The energy intensification of the site eliminates the requirement for fossil fuel thus enhancing the feasibility of the green integrated forest biorefinery.