Biorefinery Approach for Ethanol Production From Bagasse

This chapter deals with the exploitation of bagasse within the biorefinery concept for the sustainable production of ethanol. There are currently three main process routes that can efficiently convert lignocellulosic biomass into ethanol, that is, the biochemical, the thermochemical, and the hybrid. In the biochemical route, there are three consecutive steps: pretreatment aimed at breaking down the physicochemical structure of the material; hydrolysis (chemical or enzymatic) to release the sugars; followed by yeast fermentation of sugars to ethanol. The thermochemical route consists of the transformation of biomass into syngas via gasification followed by mixed alcohols catalytic synthesis. The hybrid route is, in fact, a combination of the other two technologies. Biomass is gasified and then syngas is fermented by acetogenic bacteria to ethanol. Key features, advantages, challenges, and heuristics for each technology are assessed, discussed, and presented. For this purpose, the role of process design and simulation will be elaborated and incorporated in order to evaluate and compare the feasibility of the conversion systems. In more details, methodologies regarding mass and energy balance calculations, profitability analysis, sustainability performance, and multicriteria decision analysis are thoroughly presented. In effect, a systematic methodology is developed that can support decision makers in evaluating and comparing different scenarios for biomass processing