Organosolv lignin for biofuel

Abstract

The reduction in oil reserves and the increase in greenhouse gas emissions have raised growing interest in the production and use of alternative, non-fossil fuels. The industrial production of bioethanol involves the use of amylaceous or sugary raw materials, which has aroused a hot debate on its sustainability. Bioethanol obtained from lignocellulosic biomass has proved to be an interesting alternative on account of the wide distribution of this raw material, the absence of competition with the food market and its economy in relation to conventional agricultural resources. Isolated lignin comes mainly from pulp and paper production processes. The obtainment of cellulose pulp with the Organosolv process is especially attractive as it provides highly fluid lignin that can be easily fed into oven and boiler combustion chambers. Also, Organosolv lignin contains little ash relative to other types of industrial lignin (e.g. that obtained with the kraft process), which facilitates its combustion. In this work, the Organosolv process was used to delignify lignocellulosic material from wheat straw and quantified residual lignin in the black liquor with a view to its use for energy production. The starting material was delignified with ethanol–water and acetone–water mixtures in the presence of various acids; this facilitated recycling of the solvent and recovery of dissolved lignin.