Optimization of monoethanolamine for CO2 absorption in a microchannel reactor

Abstract

In this study, CO2 absorption was performed using a MEA aqueous solution in a circular microchannel, with a diameter of 800 μm and a length of 25 cm. All experiments were carried out at atmospheric pressure with a concentration of 10% molar CO2 in the feed gas. The operational variables were temperature (15–55 °C), input solvent flow rate (0–0.04 l min−1), inlet gas flow rate (1–9 l.min−1), and MEA concentration in the solvent (0–40 wt.%). The results showed that by increasing the concentration of MEA in the solvent, and increasing the solvent flow rate, a significant increase occurred in the absorption percentage and overall gas-based volumetric mass transfer coefficient. Increasing the gas flow rate also caused a reduction in the absorption percentage and an increase in the overall gas-based volumetric mass transfer coefficient. However, the operating temperature within a range of 15–55 °C did not have a significant impact on absorption rate. In optimal operating conditions, the absorption percentage was 100%, and the overall gas-based volumetric mass transfer coefficient of 2685 (kmol h−1 m-3 kPa−1) was reached. The overall gas-based volumetric mass transfer coefficient indicates that, compared with other mass transfer devices, the use of a microchannel-reactor resulted in a higher level of increase in absorption efficiency.