Análise exergoeconômica de biorrefinarias convencionais e avançadas no setor sucroalcooleiro brasileiro

Abstract

The use of renewable energy sources has emerged as a viable alternative to meet the growing global energy demand. Among these, lignocellulosic biomass has great potential for generation. Therefore, the idea of a biorefinery using sugarcane biomass emerges as a promising alternative for energy use. Several case studies were conducted to compare the conventional model of a sugar and alcohol plant with other biorefinery configurations. Biochemical alternatives were considered for the production of lignocellulosic ethanol and biobutanol, as well as thermochemical alternatives for the production of syngas. Second-generation ethanol allows for better land use, and biobutanol is an important input for the chemical industry. The thermochemical process for the production of syngas, a highly versatile product that can be used to manufacture a variety of products, was also considered. This study considered its use for the production of diesel, gasoline, waxes, and greases through Fischer-Tropsch synthesis. For a qualitative examination of the energy generated, the methodology used was the exergoeconomic analysis of the process. A technical and economic analysis of the different biorefineries was then carried out from the perspective of the 2nd law of thermodynamics, since the inherent study of the 1st law is already widespread. With this, lignocellulosic ethanol and cellulosic butanol were also defined as plant products, in biochemical processes, and syngas, in a thermochemical process. The limit values for the distribution of sugarcane bagasse and syngas for each route were determined and the Kriging modeling methodology from previous studies was used to improve the distribution of biomass. The results of the evaluations showed that from the energy and exergoeconomic point of view, it is interesting to prioritize the production of FT fuels. The exergoeconomic analysis showed that, from the perspective of the main products, the unit costs of output from the external valorization matrix decrease with the increase in the share of bagasse for the biorefinery processes.