Hydrodynamics of Liquid–Liquid Dispersion in an Advanced-Flow Reactor

Abstract

Hydrodynamics and mass transfer of immiscible liquid–liquid flows are explored in an Advanced-Flow Reactor (AFR). These systems are emerging as one of the major commercial systems for small scale continuous flow chemistry, and characterization of the transport phenomena is critical for reaction implementation. With hexane/water as a model system, we use flow visualization techniques to determine drop size distribution, hexane holdup, and specific interfacial areas for a phase flow rate range of 10–80 mL/min. The complex geometry of the AFR with its continuously changing cross section along the flow path and strategically placed obstacles creates pressure changes that cause drop breakup and enhance mass transfer. Observations show that a wide range of average drop size (0.33–1.3 mm) can be achieved in the AFR depending upon the inlet flow rates and inlet composition. Pressure drop measurements are performed to estimate the power consumption and are used to compare the efficiency of AFR with conventional liquid–liquid contactors. The analysis shows that, similar to microreactors, the AFR can provide specific interfacial areas (1000–10 000 m–1) and overall mass transfer coefficients (1.9–41 s–1) a few orders of magnitude larger than conventional stirred tank reactors and also the static mixers.

Mass Transfer Characteristics of Ozonolysis in Microreactors and Advanced-Flow Reactors

“…Excellent mass transfer rates are also achieved in the LFR. Complete conversions are obtained within the first three hearts for all gas flow rates with the observations from Woitalka et al [15] for liquid-liquid systems, and are at least one order of magnitude larger if compared to conventional multiphase contactors [16,17].…”

“…Since the increase in throughput in the AFR is achieved by increasing the channel size (1 mm of minimum channel dimension) from the micron scale to the milli scale, questions arise regarding the mass transfer performance in this device. Previous mass transfer studies of the AFR with 1-butanol/ water/succinic acid [15], carbon dioxide/water [16], hexane/water [17] systems have shown that the overall mass transfer coefficients are in the range 0.1-10/s, depending on the flow rates of each phase [16,17].…”

WITHDRAWN: Liquid–liquid flow regimes and mass transfer in various micro-reactors

“…They dissipate energy continuously throughout the reactor's volume and generate a dispersion smaller in size than slugs [23][24][25]. The drawback of this approach is a generally greater pressure loss and/or lower residence time.…”

Continuous Lipase B-Catalyzed Isoamyl Acetate Synthesis in a Two-Liquid Phase System Using Corning® AFR™ Module Coupled with a Membrane Separator Enabling Biocatalyst Recycle

“…From the process control point of view, as well as from the production scale increase, this is beneficial as compared to the tubing system. For further scale-up of the developed process, Corning AFR™ systems should be considered as already shown in the literature for the nonenzymatic reactions [32][33][34][35]. The obtained emulsion of n-heptane droplets in an aqueous phase provided very large interfacial area for the esterification of isoamyl alcohol and acetic anhydride catalyzed by CaLB, which positions itself on the n-heptane-buffer interface.…”