Babak Aghel

In this work, mixtures of monoethanolamine with four different alcoholic solvents of methanol, ethanol, propanol, and butanol were used for carbon dioxide (CO2) absorption in a microreactor. These alcoholic mixtures were compared with a mixture of monoethanolamine and water, as this is one of the common solvents in this field. To this objective, the effect of three operating parameters, desorption temperature from 55 °C to 95 °C, the solvent flow rate from 1 mL/min to 5 mL/min, and solvent concentration from 10% to 50%, were investigated on the process of CO2 desorption in the microreactor. Furthermore, the amount of energy consumed per kilogram of CO2 desorption (E) by solvents including methanol, ethanol, propanol, butanol, and water was measured to determine the rate of desorption and energy consumption. The results showed that alcoholic solvents reduced E by more than one-third. This is more than water, which is most widely used solvent for monoethanolamine. Also, using a microreactor as a piece of genuine mass transfer equipment during the desorption process reduced energy consumption significantly. Finally, the results show that the lowest E was for the solvent of monoethanolamine + methanol, which under optimal conditions is 0.41 MJ per kg desorbed CO2 (MJ.kg-of-CO2−1). The values for the solvents of monoethanolamine + ethanol, monoethanolamine + propanol, monoethanolamine + butanol were 0.48, 0.55, and 1.1 MJ.kg-of-CO2−1, respectively. However, the values for the solvent of monoethanolamine + water in the microreactor were obtained at the optimum operating condition of about 1.39 MJ.kg-of-CO2−1.