Otimização do processo de obtenção de ésteres metílicos a partir de óleo residual de soja.

Abstract

The most used material for the production of biodiesel in Brazil is refined soybean oil. Therefore, the optimization of the biodiesel production from waste oils can be considered a procedure of great importance, since one of the most costly stages of the biodiesel production process is the obtaining of the raw material. The essential steps for the consolidation of the research included the preparation of the oil, the preparation of the same for the submission of the chemical reactions, determination of the physicochemical characteristics of the oil after the preparation of the oil, obtaining the biodiesel and physical-chemical analyzes of the product obtained and statistical treatment of the established response (esters content). The oil used had a free fatty acid content of 3.6%. The results for the analyzes of the physicochemical characteristics of biodiesel were: 4.1 mm2s-1 for kinematic viscosity; the range of 0.740-0.791 gmL-1 for the absolute density; acid value of 0.41 mg KOH / g and peroxide index of 16.1 meq / 100 g of oil. With respect to the ester content of the biodiesel obtained it was observed that the highest yield occurred when the reaction was carried out at a temperature equal to 26 ° C; the catalyst concentration of 0.5% and the molar ratio alcohol: oil of 6.0. Analyzing the response surfaces it is understood that higher yields can be achieved when reactions are carried out at temperatures below 29 ° C, catalyst concentration between 1.0% and 1.5% and alcohol / oil molar ratio below 7.6 . The only factor that exerts a linear effect on the increase of ester content in biodiesel obtained in a significant way was the effect of temperature. As for the quadratic effects, only the interaction between the temperature and the catalyst concentration presented statistical significance.