Development of continuous processes for vegetable oil alcoholysis in microfluidic devices

• Published in: Oléagineux corps gras lipides Vol. 20; no. 1; pp. 23 - 32
• Main Authors: Richard, Romain, Dubreuil, Brigitte, Prat, Laurent, Thiebaud-Roux, Sophie
• Format: Journal Article
• Language: English
• Published: EDP 01.01.2013; EDP Sciences
• Subjects: biodiesel; Chemical and Process Engineering; Engineering Sciences; ethanolysis; Food engineering; Life Sciences; microreactors; modelling; NIR spectroscopy; simulation; Biotechnologies
• ISSN: 1258-8210; 2272-6977; 1950-697X; 2257-6614
• DOI: 10.1051/ocl.2012.0479

Biodiesel can be produced from vegetable oils, animal fats, and waste cooking oils by transesterification with ethanol (also called ethanolysis) in order to substitute fossil fuels. In this work, we were interested in the transesterification reaction of sunflower oil with ethanol, which leads to ethyl esters, used to date for applications principally in food and cosmetic industry. To open the application field to biofuels (to substitute current fuels resulting from fossil resources), the process efficiency has to be developed to be economically profitable. The batch reaction of vegetable oil ethanolysis was transposed to a micro-scaled continuous device (PFA tube of 508 mm internal diameter), inducing better heat and mass transfer. Study of the influence of the operational conditions (reactants flow, initial ethanol to oil molar ratio, temperature. . .) revealed the favourable reaction parameters necessary to reach high conversions and yields. In these conditions, it is possible to acquire kinetics data at the first seconds of the reaction, which was not feasible in a conventional batch process. These data were used to model occurring phenomena and to determine kinetic constants and transfer coefficients. The model was subsequently used to simulate reactions with other operational conditions. To acquire these data in microreactors, an on-line analysis method by Near InfraRed (NIR) spectroscopy was developed by using gas chromatography as a reference method. PLS models were then set up to quantify on-line the major compounds contents during the reaction.