The multiphase micro-structured devices such as microchannels have been recently taken into consideration to replace the conventional equipment in different applications. The mass transfer coefficients and the interfacial area in the multiphase microchannels are much larger than those in the conventional equipment. This paper reviews the experimental studies on mass transfer in gas-liquid and liquid-liquid microchannels. Proposed flow pattern maps are compared. The featured researches corresponding to the effects of the operating conditions and the geometry of the microchannels on mass transfer are discussed. Literature review shows that influences of geometrical parameters are not investigated as extensively as those of operating conditions and thus, vague aspects of geometrical parameters effects exist. There are inconsistencies between results of some researchers and most of these are due to using dissimilar microchannel materials, unalike dominant mechanisms at different investigated operating conditions, different approaches to change the independent variable, etc.

Mass transfer between phases in microchannels : A review

The objective of the study is to compare the performance of microchannels and conventional stage-wise extractors for liquid–liquid extraction by using a standard phase system. Three different microchannels – a T-junction microchannel, a serpentine microchannel and a split-and-recombine microchannel – have been used in the experiments. Conventional extractors are represented by a mixer-settler and an annular centrifugal extractor. The phase system used in the experiments is water (succinic acid) n-butanol system which is one of the standard phase systems recommended by the European Federation of Chemical Engineering. The extractors have been compared on the basis of percentage extraction, overall volumetric mass transfer coefficient and specific extraction rate. When compared on the basis of percentage extraction, performance of the microchannels and the conventional stage-wise extractors is found to be almost similar. Maximum values of overall volumetric mass transfer coefficient and specific extraction rates are found to be more in the microchannels than in the conventional stage-wise extractors. The ratio of maximum overall volumetric mass transfer coefficient in microchannels and conventional stage-wise extractors is found to range from 1 to 8.1. The ratio of maximum specific extraction rate in microchannels and conventional stage-wise extractors is found to range between 2.3 and 9.7.

Liquid–liquid extraction in microchannels and conventional stage-wise extractors: A comparative study

Hydrodynamics and mass transfer in liquid-liquid non-circular microchannels: Comparison of two aspect ratios and three junction structures

Process Development and Scale-up of the Continuous Flow Nitration of Trifluoromethoxybenzene

Mass transfer is a basic phenomenon behind many processes like reaction, absorption, extraction etc. Mass transfer plays a significant role in microfluidic systems where the chemical / biological process systems are shrinkened down to a micro scale. Micro reactor system, with its high compatibility and performance, gains a wide interest among the researchers in the recent years. Micro structured reac-tors holds advantages over the conventional types in chemical processes. The significance of micro re-actor not limited to its scalability but to energy efficiency, on-site / on-demand production, reliability, safety, highly controlled outputs, etc. Liquid-liquid two phase reaction in a microreactor system is highly demandable when both reactants are liquids or when air medium cannot be suitable. This arti-cle overviews various liquid-liquid flow regimes in a microchannel. Discussions on the hydrodynamics of flow in micro scale are made. Considering the importance of mass transfer in liquid-liquid systems and the advantage of slug regime over other regimes, the article focuses especially on the mass trans-fer between two liquid phases in slug flow and the details of experimental studies carried out in this area. The advantages of slug flow over other flow regimes in micro structured reactor applications are showcased. © 2014 BCREC UNDIP. All rights reserved Received: 31st May 2014; Revised: 6th August 2014; Accepted: 14th August 2014 How to Cite : Antony, R., Giri Nandagopal, M.S., Sreekumar, N., Rangabhashiyam, S., Selvaraju, N. (2014). Liquid-liquid Slug Flow in a Microchannel Reactor and its Mass Transfer Properties - A Review. Bulletin of Chemical Reaction Engineering & Catalysis ,9(3): 207-223. (doi:10.9767/bcrec.9.3.6977.207-223) Permalink/DOI : http://dx.doi.org/10.9767/bcrec.9.3.6977.207-223

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Liquid-liquid Slug Flow in a Microchannel Reactor and its Mass Transfer Properties - A Review

Liquid–liquid extraction based on droplet flow in a vertical microchannel

Computational Fluid Dynamics (CFD) was used to simulate the flow field of gas-liquid Taylor flow in circular capillaries. The separate influence of gas bubble velocity Vb,Taylor unit length LUC, film length Lfilm and liquid film thickness δfilm on both the liquid slug velocity Vx,top and film velocity Vx,film were investigated. The values of Vx,top are mainly dependent on Vb and δfilm while Vx,film relies on all the four parameters.

Jing Tang

Papers

Liquid–liquid extraction based on droplet flow in a vertical microchannel

CFD Simulation on Flow Field of Gas-Liquid Taylor Flow in Circular Capillaries