Experimental investigation of the liquid volumetric mass transfer coefficient for upward gas-liquid two-phase flow in rectangular microchannels

Abstract

-The gas-liquid two-phase mass transfer process in microchannels is complicated due to the special dynamical characteristics. In this work, a novel method was explored to measure the liquid side volumetric mass transfer coefficient k L a. Pressure transducers were utilized to measure the pressure variation of upward gas-liquid two-phase flow in three vertical rectangular microchannels and the liquid side volumetric mass transfer coefficient k L a was calculated through the Pressure-Volume-Temperature correlation of the gas phase. Carbon dioxide-water, carbon dioxide-ethanol and carbon dioxide-n-propanol were used as working fluids, respectively. The dimensions of the microchannels were 40 μm×240 μm (depth×width), 100 μm×800 μm and 100 μm×2000 μm, respectively. Results showed that the channel diameter and the capillary number influence k L a remarkably and that the maximum value of k L a occurs in the annular flow regime. A new correlation of k L a was proposed based on the Sherwood number, Schmidt number and the capillary number. The predicted values of k L a agreed well with the experimental data.

Mass Transfer Correlation and Optimization of Carbon Dioxide Capture in a Microchannel Contactor: A Case of CO2-Rich Gas

“…Note that, the K L a is embedded in the Sherwood number as modified Sherwood number (Sh*) (see Equation 13). The correlation of our model was in line with those reported in the literature [29,30].…”

Einfluss mikrostrukturierter statischer Mischer auf den Gas/Flüssig‐Stofftransport in einem engen Rechteckkanal

“…sind jene Studien zusammengengestellt, die entweder in kleinen Kanälen d h < 5 mm oder in Geometrien mit zusätzlichen konvektionserhöhenden Maßnahmen (z. B. Einbauten oder Geometriemodifikationen) durchgeführt wurden , . Anlehnend an die bereits existierenden Forschungsarbeiten wird zur Bestimmung des k L a Ph ‐Wertes des Miprowa® ebenfalls die physikalische Absorption von CO 2 in H 2 O verwendet.…”

“…Die in der Literatur gefundenen Studien zur experimentellen Bestimmung von k L a Ph ‐Werten in Kanälen mit verringerten Strukturdimensionen und, sofern vorhanden, unter dem Einfluss von Intensivierungsfaktoren wie z. B. statischen Mischern unterscheiden sich bezüglich der Prozesseinstellungen (Leerrohrgeschwindigkeiten, Gasgehalte) mitunter deutlich voneinander , . Yue et al.…”

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

“…This is also verified in the literature. [ 36,41 ] In addition, the change of k L, film a film and k L, cap a cap with velocity in different solutions was obtained. From Figure 12A,B it can be seen that k L, all a all > k L, film a film > k L, cap a cap , and k L, all a all and k L, film a film are closer.…”

“…As shown in Table 1, the empirical formulas about the liquid side volumetric mass transfer coefficients were studied by researchers, [ 10,36–49 ] and this data was obtained mainly by experiments and a few simulations. Compared with the original work, this paper studied and simulated the absorption and mass transfer process of CO 2 by adding MEA aqueous solution and compared it with the absorption of CO 2 by water, ethanol, and NaOH aqueous solution.…”