CO2 capturing in cross T-junction microchannel using numerical and experimental approach

Numerical and experimental studies were carried out for the analysis of hydrodynamics and volumetric mass transfer coefficient (k(L)a) in a cross-T junction microchannel for gas-liquid, two phase flow system. Initially, CO2-water hydrodynamics simulation was performed using ANSYS-FLUENT 2021 R2 and volume of fluid technique. Through the numerical simulation, fluctuation in pressure drop with variation in volume fraction was calculated for the slug flow in a 1 mm hydraulic diameter microchannel. After that mass transfer equations were coupled with the flow equations for CO2-ethyl glycol, CO2-water, and CO2-ethyl alcohol systems to understand the mass transfer mechanism using two film theory concepts. Computational fluid dynamics model was validated by comparing results with the experimental data. An empirical co-relation was also developed to measure the bubble length with its position in the direction of fluid flow. CO2 and solvents velocities were 0.21-0.424 m/s for both the phase. Effect of solvents and film thickness (0.01-0.05 mm) on volumetric mas transfer coefficient were investigated at different temperatures range i.e., T = 298.15 K and 303.15 K (experimental approach) and 298.15-318.15 K (numerical approach). The results obtained in numerical simulation and experimental work show that the total volumetric mass transfer coefficient (range 0.1-0.8 1/s) increases with the gas velocity however, it decreases with increasing film thickness (0.01-0.05 mm) and temperature (T = 298.15 K and 303.15 K). The present work gives an advantage over the conventional channel (e.g., packed bed column) and the other type of T-junction microchannel (e.g., symmetric T-junction) by providing a high mixing rate, interfacial area, and high mass transfer rate.

Automated summary

Numerical and experimental studies were conducted to analyze the hydrodynamics and volumetric mass transfer coefficient (k(L)a) in a cross-T junction microchannel for gas-liquid, two phase flow system. The simulations and experiments focused on CO2-water and other CO2-solvent systems, investigating factors such as film thickness and temperature. The results show that the total volumetric mass transfer coefficient increases with gas velocity but decreases with increasing film thickness and temperature.