Thermochemical conversion of sugar industry by-products to biofuels

Replacement of petroleum by other energy sources is one of the principal challenges of contemporary engineering. One of the most promising substitutes for petroleum is biomass, chemically converted into fuel. For instance, as the world's biggest producer of sugarcane, Brazil generates large quantities of agricultural residues from sugarcane cultivation which could be used to produce biofuels for transportation and aviation (i.e. jet fuel) without much difficulty. Furthermore, sugar beet industry generates important amount of waste that could be valorized into biofuels. The purpose of this article is to review the different technologies currently available for the production of biofuels via a thermochemical pathway using sugarcane bagasse and sugar beet pulp as feedstock, with specific interest in using feedstock gasification and subsequent conversion of the synthetic gas into fuel. Gasification is a longstanding process of conversion of carbonaceous material into a gaseous compound (syngas) and a solid output, called char. Several kinds of gasifiers are described, as well as the syngas cleaning-up process, and the characteristics of several processes through which syngas is converted into synthetic fuel are detailed, including Fischer-Tropsch (FT), Methanol-to-gasoline (MTG), Methanol-to-olefins (MTO) as well as pyrolysis.