Intensification for CO2 alkaline absorption in H2-rich stream purification with T-type microchannel

The limited conversion of CO 2 hydrogenation generates a large amount of H₂-rich stream. Efficient removal of CO 2 from H₂-rich streams is critical for hydrogen purification and downstream utilization. A three-dimensional absorption model is developed to demonstrate the characteristics of chemical absorption and mass transfer in a T-type microchannel with concave or convex structure. The Taylor bubble flow in microchannel would enhance the interfacial mass transfer rate even in the length of 5 mm within second. Reducing diameter and gas-liquid ratio ( R GL ) will enhance the interfacial mass transfer efficiency to significantly improve H 2 -rich purification. Both concave and convex structure would change the length and residence time for the single bubble and cause enhanced interfacial dynamics for the gas-liquid flow, resulting in higher CO 2 absorption rate of 53% and 72.5% than the 51.48% for cylindrical microchannel at 5 mm length at R GL = 8:3. Specially, the CO 2 absorption rate for convex microchannel can reache 88.7% within 5 mm length at R GL = 1, while it is 87.42 % within 15 mm length at R GL = 8:3 to realize the H 2 purity of 99.41%.