A multiobjective experimental based optimization to the CO2 capture process using hybrid solvents of MEA-MeOH and MEA-water

To achieve the reduction of total energy consumption of CO2 capture without the major drawbacks of conventional amine solvents, the superior performance of a blended physical-chemical solvent, MEA-MeOH, was experimentally compared with that of MEA aqueous absorbent in lab-scale absorption/desorption towers, equipped with stainless steel pall ring packings. Considering the typical industrial requirements, the main operating variables accounted for each solvent were the operating temperature (35–55 °C), amine concentration (15–30 wt%), gas flow rate (50–100 l/min), liquid flow rate (0.75–1.25 l/min), CO2 concentration in the inlet gas (5–15 mol %), and the reboiler heat duty (1.4–2.2 kW). Response surface methodology was applied to give a quadratic mathematical model for obtained empirical volumetric overall mass transfer coefficients (KGaV). Based on the drastic increase of the energy requirement for solvent regeneration, a multiobjective optimization framework has been made to achieve the maximum desirable values for the KGaV, and the absorption percentage (Φ) with the minimum energy consumption (Ω). It was suggested that under the optimum operating condition, adding methanol to an aqueous MEA solution, reduces the regeneration energy consumption by 12%, while augmenting the CO2 absorption percentage (Φ) by 9.1%.