Research on the mass transfer in gas-liquid flow of microchannels for CO2 absorption

Abstract

Carbon capture technology has been recognized as an effective method for reducing greenhouse gas emissions. The experimental system utilizing monoethanolamine (MEA) solution in microchannel for the absorption of CO₂ from a mixed gas was developed. The flow and mass transfer characteristics of Taylor bubbles in T-shaped microchannel during the absorption process were analyzed. Due to surface tension effect, Taylor bubbles could not fully occupy the corner of the channel, leading to the generation of leakage flow. To accurately describe the extent of leakage flow and correct the flow parameters, section coefficient was introduced as a correction factor, and equivalent leakage factor was proposed to directly characterize the proportion of leakage flow relative to the total flow. Quantitative analysis indicated that the degree of leakage flow increased with liquid flow rate. The results demonstrated that under conditions of liquid phase concentration C (MEA) = 10 wt%, liquid phase flow rate Q_L = 70 mL/min, and gas phase flow rate Q_G = 70 mL/min, the maximum CO₂ absorption efficiency reached 96.36 %. Meanwhile, the mass transfer coefficient stabilized at 1.893 × 10⁻³ m/s, and the energy consumption for CO₂ capture was only 2.272 MJ/ kg CO₂.