Modeling and simulation of soybean oil transesterification reaction using CFD and experimental data
Victor Gabriel Santos Silva1; Amanda Santana Peiter2; Antônio Carlos Brandão de Araújo3; Jose Jailson Nicacio Alves3; João Inácio Soletti2; Sandra Helena Vieira de Carvalho2; José Luis Gomes Marinho2; Rafaela Gabriel2
1 Federal University of Parana; 2 Federal University of Alagoas; 3 Federal University of Campina Grande
doi:10.20906/CPS/CILAMCE2017-0946
Resumo
The use of fuels derived from petroleum rises every year, which results in the increase of atmospheric pollution. Due to this, the global economy invests on alternative sources of energy. The biodiesel exists as an alternative for diesel. Biodiesel can be obtained from the reaction of transesterification, in which the triglycerides present in the vegetal oils or animal fat react with a short-chain alcohol in the presence of a catalyst to obtain the fatty acid esters. Impellers of various types can be used to produce the agitation and mixing in the liquid phase. The goal of this work is to simulate the reaction of transesterification of the soybean oil with methanol in the presence of sodium hydroxide to produce biodiesel using different impellers, using experimental data to estimate the kinetics of the reaction, which was considered first order based on the results of the curve fitting. The reaction were conducted with baffles, agitation velocity of 450 rpm, oil:alcohol molar ratio of 1:7, 0,5% mass of catalyst, temperature of 30ºC and a reaction time of 60 minutes. The impellers evaluated were the Rushton turbine and the oblique blade impeller. The computation fluid dynamics (CFD) technique permits a deep and detailed study, including analysis of pressure and velocity fields, without the need for advanced experimental techniques or financial costs for implementing a pilot plant. This technique is mainly developed in commercial packages like Ansys, that offers many graphical interfaces and models. In this work, a geometry and a mesh for the tank were created with the different impellers and the reaction conditions inserted to get the results. Since the reaction is very dependent of the goodness of mixing of the oil and the alcohol, it was necessary to use a turbulence model and we utilized k-ε model, since is currently the one with better validation by the industry. The system was considered monophasic, due to limitations of Ansys CFX and multicomponent, to better represent the variety of fluids involved in
Palavras-chave: soybean oil transesterification reaction; reacting mixture; experimental data validation; computational fluid dynamics