Modelagem, simulação e análise técnico-econômica-ambiental do processo de extração de óleo de soja por hexano e etanol e da produção de biodiesel

Abstract

Brazil is the second largest producer of soybean, with the projection of becoming the largest producer in 2019/2020. All Brazilian soybean oil is produced by the extraction process with hexane, an oil derivative. One way to make the extraction process more sustainable would be to replace hexane by ethanol, a renewable solvent widely produced in Brazil. Thereby, the objective of this work was to perform the techno-economic-environmental analysis, together with the modeling and simulation, of the soybean oil extraction process and biodiesel manufacturing. The net present value (NPV) was adopted as the economic metric. For the environmental analysis the life cycle analysis (LCA) of the process was carried out. The soybean oil preparation, extraction, refining and transesterification processes were simulated in EMSO (Environment for Modeling, Simulation and Optimization) software. The products considered in the process were: refined soybean oil, soybean meal, soybean lecithin, pelleted soybean hulls, glycerol and biodiesel. The thermodynamic parameters were estimated by group contribution methods for each element that composes the raw material and the products. The extraction processes using hexane, hydrated ethanol and anhydrous ethanol were simulated. The minimum attractive rate of return (MARR) was 11%. The NPV values calculated for a period of 20 years of operation were positive for all cases analyzed, indicating that all the evaluated processes are economically viable. However, the process employing hexane had a NPV approximately 10.2% higher than the best process employing ethanol (hydrate). On the other hand, the replacement of hexane by ethanol resulted in lower Global Warming Potential (GWP). The substitution of hexane by hydrous ethanol would avoid the emission of approximately 10,600 t of CO2eq per year in an industry that crushes 125 t/h of soybean.