Coiled flow inverter as a novel alternative for the intensification of a liquid-liquid reaction. (21st September 2017)

• Record Type: Journal Article
• Authors: López-Guajardo, Enrique; Ortiz-Nadal, Enrique; Montesinos-Castellanos, Alejandro; Nigam, Krishna D.P.
• Is Part Of: Chemical engineering science. Volume 169(2017)
• Page Start: 179
• Page End: 185
• Publication Date: 2017-09-21
• Subjects: Process intensification -- Helical coiled tube -- Liquid-liquid reaction -- Coiled flow inverter -- Transesterification; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2017.01.016
• Languages: English
• ISSNs: 0009-2509

Abstract

Highlights: The intensification of a liquid-liquid reaction is possible in CFIs. Performances between CFIs, Batch, Helical and Straight Tube reactors are compared. 96% oil conversion is achieved within 4 min residence time in the CFIs. No further improvement in oil conversion is observed after seven 90° bends. Experiments with a reduction in methanol excess are explored in CFIs. Abstract: This paper explores a novel alternative to conventional biodiesel production by taking advantage of the mixing, mass and heat transfer enhancement inherent in coiled flow inverters (CFIs) using the transesterification of fatty acids as a model reaction. The results show that the reaction can be carried out twelve times faster in a CFI than in a batch reactor, with a conventional oil to methanol molar ratio of 1:6 (100% excess methanol). The mixing enhancement in CFIs increases the mass transfer between the reacting phases, achieving conversions of up to 93% for 2 min residence time at 10 ml/min with seven 90° bends. The performance of CFIs was compared to that of simple helical and straight tube reactors under the same operational conditions. The conversion observed in the CFIs was up to 18% higher than the conversion obtained in the helical and straight tube reactors. However, all the reactors achieved similar oil conversions when a longer residence time (4 min) was allowed under the same flow rate conditions. Additional experiments with CFIs were carried out in order to explore lower oil:methanol molar ratios. The experimental results suggest that CFIs are capable of achieving conversions of up to 90% at 50% methanol molar excess (1:4.5 oil:methanol ratio) with a 4 min residence time, which contrasts with the 60 min required in batch reactors to achieve the same conversion. The results confirm that CFIs successfully intensify liquid-liquid reactions such as the transesterification of fatty acids when compared to a batch reactor.