Influence of Process Parameters on the Performance of Microdevices Applied to Exhaust Gas Treatment with MEA

Abstract Postcombustion CO2 capture remains a significant challenge due to the low partial pressure of CO2 and limited gas–liquid contact efficiency, reducing the performance of conventional absorption systems and increasing energy demand. Microdevices offer a promising alternative, enabling process intensification through enhanced mass transfer and reduced diffusion limitations. This study investigated CO2 capture performance in microchannel reactors, evaluating different operating conditions and channel dimensions for postcombustion gas treatment. Experiments were conducted in three microchannel reactors varying: (i) MEA concentration (0.5–2.5 M); (ii) gas–liquid ratio (15:1, 10:1, and 5:1); (iii) channel diameter (0.6 and 0.9 mm); and (iv) reactor length (150 and 250 mm). Capture efficiency and kLa yielded reproducible results of 36.14–89.77% and 3.19–14.69 s–1, respectively. Results indicated that operating with 2.0 M MEA at a 15:1 gas–liquid ratio was most advantageous in reactors with smaller diameters and longer lengths (D = 0.6 mm, L = 250 mm). This maintained high capture efficiencies while reducing solvent-related energy costs. Recirculation tests in the optimal microdevice showed a gradual decrease in capture efficiency (81.13–59.15%) and kLa (11.87–6.40 s–1). However, after 20 cycles, the MEA solution was not saturated, indicating remaining CO2 capture capacity. Overall, these findings reinforce microchannel reactors as a viable, efficient alternative for intensifying postcombustion CO2 capture.