Biorefineries productive alternatives optimization in the brazilian sugar and alcohol industry

Abstract

A technical, economic and environmental analysis of different biorefinery configurations is carried out, considering the integration of different biomass technologies with sugar and ethanol plants. Biochemical routes for the production of lignocellulosic ethanol and biobutanol from ABE (Acetone-Butanol-Ethanol) fermentation were considered as alternatives for conversion, also a thermochemical process for the production of syngas. Second-generation ethanol favors better land use, and biobutanol is an important input for the chemical industry, as well as producing acetone and ethanol as co-products. Syngas from the thermochemical process is very versatile raw material, which can be used to manufacture various products. Syngas was considered for Diesel production through Fischer-Tropsch synthesis process, and also for electricity production. To verify biomass distribution in biorefinery processes, that allows reaching best results from a techno-economic, and environmental point of view, a computational experiment was carried on, using the Kriging method for plant optimization. Solving problems using mathematical modeling as an alternative to traditional methods of optimization can be simplified without loss of generality, precision or need of computer over time. Results show that, from an energy point of view, thermochemical routes perform better, in addition to being able to avoid large amounts of CO2eq emissions. From an economic point of view, biochemical routes prove to be only feasible when all available bagasse is destined for these alternatives. Finally, the process of lignocellulosic ethanol presents a superior performance, having the best combination of analyzed indicators, resulting in a more sustainable process. A Brazilian sugar and alcohol factory was taken as a case study; its results can be extended to any similar installation that uses biomass as a raw material.