Effects of bubble behavior on CO 2 absorption into [emim][ AcO ]/sulfolane solution in honeycomb fractal microchannel

Abstract The honeycomb fractal structure is an efficient mass and energy transportation system. In this study, the influences of IL concentration of absorbent and operating conditions on the gas–liquid two‐phase flow characteristics and CO 2 absorption performance were visually investigated in a honeycomb fractal microchannel. Five flow patterns were observed: non‐breakup and non‐coalescence, non‐breakup and coalescence, breakup and non‐coalescence, breakup and coalescence, and unstable flow regimes. As bubble coalescence is inconducive to CO 2 absorption efficiency, the criterion for predicting bubble coalescence was proposed to prevent its occurrence. The distribution of bubbles in the microchannel was characterized by introducing the asymmetry factor and gas holdup, and it was found that the two parameters are closely related to the flow pattern. The influences of the operating condition, flow pattern, and physical property of the absorbent on CO 2 absorption were studied systematically, and an effectively predictive correlation of CO 2 absorbed fraction was obtained.