Desempenho de microssistemas no tratamento de gás exausto com MEA: influência dos parâmetros operacionais

Abstract

The need to reduce greenhouse gas emissions has driven the development of technologies for CO2 mitigation. Chemical absorption using monoethanolamine (MEA) is one of the most efficient alternatives; however, the solvent regeneration step remains a major challenge. In this context, microchannel reactors emerge as a promising approach, with the potential to increase energy efficiency and reduce operational costs. Therefore, this study aimed to investigate the CO2 capture efficiency of MEA solutions in microsystems, evaluating different operating conditions and channel dimensions for the treatment of flue gases. Experimental tests were carried out using three distinct microsystems, varying the following parameters: (i) MEA concentration (0.5, 1.0, 2.0, and 2.5 mol/L); (ii) gas-to-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 were assessed under these conditions and showed reproducible results in the range of 36.14–89.77% and 3.19–14.69 s⁻¹, respectively. The effects of operational conditions on these parameters were also analyzed and discussed. The results indicated that operating with 2.0 M MEA at a gas-to-liquid ratio of 15:1 was more advantageous when applied in reactors with smaller diameters and greater lengths. Under these conditions, high capture efficiencies were maintained while reducing the energy cost associated with the use of the absorbent. Recirculation tests showed a gradual decrease in capture efficiency (81.13–59.15%) and kLa (11.87–6.40 s⁻¹) in the best-performing microsystem (D = 0.6 mm and L = 250 mm), although the MEA solution was not saturated even after 20 cycles, indicating its continued potential for CO2 capture. Thus, the results reinforce the potential of microsystems as a viable and efficient alternative for process intensification in CO2 capture applications from flue gas treatment.