Effect of channel dimension on biodiesel yield in millireactors produced by stereolithography

Abstract

ABSTRACT Industrial research departments and chemical engineering institutes have begun to adopt additive manufacturing technologies, such as stereolithography for producing special types of reactors for continuous production. Microreactors have been widely used to improve the mass and heat transfer processes between immiscible liquid-liquid phases, but with the disadvantage of requiring sophisticated technology for their manufacture. In this paper, an approach for producing millireactors by stereolithography and rapid optimization of millireactor design with circular cross-section is presented. Transesterification of vegetable oils with alcohols is widely used method for biodiesel synthesis, generally taking place in a batch reactor. Microreactors due to their short residence times and high biodiesel yields are currently being explored for continuous production, but have disadvantages in low production volumes and high pressure drops. To overcome above-mentioned problems, millireactors with channel diameters from 1.5 mm to 3.5 mm were produced in order to investigate the impact of channel dimensions on conversion of sunflower oil to fatty acid methyl esters (FAME). Transesterification reaction of sunflower oil using methanol with addition of KOH base catalyst to FAME was monitored by Fourier-transform infrared spectroscopy, gas chromatography, and nuclear magnetic resonance. Results show that millireactors with smaller channel dimensions and processes with higher temperatures at certain residence times can be used to achieve better biodiesel yield in much shorter time than batch reactors. In addition, continuous way of FAME production in millireactors is presented. Production in millireactors provided an improvement when compared to microreactors because they have low pressure drops and higher production volumes.