Otimização da síntese de misturas de biodiesel mamona e amendoim como o uso do ultrassom

Abstract

Biodiesel is an alternative to renewable fuel production in the national energy matrix comes from oilseeds such as the castor bean and peanuts which are plants grown by farmers in semi-arid northeast. In the paper aimed to optimize via ethyl, basic catalysis using ultrasound system 3 biodiesel synthesis of castor beans and peanuts. Initially we used the designs Box Behnken 2 with 12 factorial points (+1 and -1), to estimate the experimental error were used three central points (0), totaling 15 experiments. They were analyzed three independent variables catalyst concentration, proportion castor beans/peanut, molar ratio alcohol:oil due to the mass yield of biodiesel. We analyzed the effects of the variables and the significance using the Student test and analysis of variance to 95% probability. Aiming to optimize the reaction conditions of synthesis used a second Box Behnken 2 design with 12 factorial points, three central points with three independent variables: catalyst concentration, castor bean/peanut proportion and molar ratio alcohol / oil, adapting the levels under the influence of variables from the previous design. The 3 experimental optimum condition was determined using response surface methodology. The ultrasound system is feasible for biodiesel synthesis castor beans and peanuts, because we used a reaction time and temperature under 60 minutes and 40°C respectively, without compromising the mass yield of biodiesel. The design has set a great experimental conditions: catalyst concentration 1.06%, proportion castor bean/peanut 32.6/67.4 and molar ratio alcohol/oil 22.95:1. In these experimental conditions the maximum theoretical yield calculated was 91,83%. After application of the theoretical conditions was observed a 91,56% yield small difference exists between 0,27% yields.