CENTRAL COMPOSITE DESIGN APPLIED TO BIOQUEROSENE OBTAINING SYSTEM VIA HETEROGENEOUS CATALYSIS

Abstract

In this work biokerosene was produced by the esterification reaction (using heterogeneous catalyst such as Amberlyst^TM 15) of free fatty acids of C6 to C16 carbon atoms derived from babassu oil (Orbinya speciosa) using a 2³ factorial experimental design with central composite. Scanning electron microscopy morphology and the thermogravimetry analysis was used to indicate the working range of the catalyst. The process parameters studied were the reaction temperature between 70 °C to 100 °C, catalyst concentration between 5 % to 10 % and reaction time between 240 minute to 480 minute. As the factorial design response parameter was evaluated the methyl esters content. The process optimization was performed using the response surface methodology (RSM) and the polynomial model of second order. It was observed that the most influential process variables were the reaction temperature and time, the highest conversion of methyl esters was obtained with 7.5 % catalyst; reaction temperature of 85 °C and 360 minutes of reaction. The best conversion of the reaction was 94.7 % on biofuel. Utilizing the MRS with second-order polynomial model, the optimized conditions achieved for the esterification reaction with Amberlyst^® 15 were: a temperature of 90.0 ° C, catalyst amount of 7.3 %, and reaction time 338.2 minutes . The expected theoretical yield of conversion into free fatty acids from C6 to C16 carbon atoms in biokerosene was 95.7 %.