Liquid–liquid two‐phase flow in ultrasonic microreactors: Cavitation, emulsification, and mass transfer enhancement

Abstract

The effects of ultrasound on the hydrodynamic and mass transfer behaviors of immiscible liquid–liquid two‐phase flow was investigated in a domestic ultrasonic microreactor. Under ultrasonic irradiation, cavitation bubble was generated and underwent violent oscillation. Emulsification of immiscible phases was initiated by virtue of oscillating bubbles shuttling through the water/oil interface. The pressure drop was found to decrease with increasing ultrasound power, with a maximum decrement ratio of 12% obtained at power 30 W. The mass transfer behavior was characterized by extraction of Rhodamine B from water to 1‐octanol. An enhancement factor of 1.3–2.2 on the overall mass‐transfer coefficient was achieved under sonication. The mass transfer performance was comparable to passive microreactor at similar energy dissipation rate (61–184 W/kg). The extraction equilibrium was reached under a total flow velocity 0.01 m/s and input power 20 and 30 W, exhibiting its potential use in liquid‐liquid extraction process. © 2017 American Institute of Chemical Engineers AIChE J, 64: 1412–1423, 2018

Pulsed ultrasound for temperature control and clogging prevention in micro-reactors

“…Experimental setupExperiments were carried out in an ultrasonic micro-reactor (USMR). The USMR consists of a microreactor glued to a Langevin-type transducer[34][35][36]. The Langevin-type transducer is designed to vibrate as a half-wavelength resonator in the longitudinal direction.…”

Intensification of liquid–liquid two‐phase mass transfer in a capillary microreactor system

“…Typical values of the overall volumetric mass transfer coefficients for batch reactors, static mixer, packed‐bed microchannel, Corning Advanced‐Flow Reactor (AFR), porous reactor, and ultrasonic microreactor, and the microreactor system with capillary modifications (i.e., BC‐2) against the specific energy dissipation are plotted in Figure , in which the data in this current work are compared with those taken from pictures presented in the literature . As shown in Figure , the microreactor system with capillary modification (BC‐2) in our work is superior to most of other reactors in terms of specific energy dissipation at the same overall volumetric mass transfer coefficients, and its performance is similar to that of Corning Advanced‐Flow Reactor (AFR).…”

“… Overall volumetric mass transfer coefficient as a function of the specific energy dissipation for different liquid−liquid reactor systems (the data of Corning AFR, batch reactor, static mixer, porous reactors, packed‐bed microchannel, and ultrasonic microreactors were taken from pictures presented in the literature. [Color figure can be viewed at http://wileyonlinelibrary.com]…”

Numerical simulation of the mass transfer process of CO2 absorption by different solutions in a microchannel

“…Most of the research focuses on the flow, heat, and mass transfer of gas-liquid and liquid-liquid two-phase flow without reaction in microchannels, and researchers usually use experimental methods to study chemical mass transfer. [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] However, there are many uncertain factors in the experimental process, such as environmental impact and errors caused by equipment problems; therefore, it is still necessary to study mass transfer theory by using the computational fluid dynamics (CFD) method. [30][31][32][33][34][35] Shao et al [18] divided the gas-liquid twophase flow in the microchannel into six flow patterns: bubble flow, slug flow, mixing flow, Taylor-annular flow, stratified flow, and annular flow.…”