Comparative study of CO2 capture efficiency using sodium hydroxide and monoethanolamine solutions in a spray column

This study investigates the CO 2 absorption performance of sodium hydroxide (NaOH) and monoethanolamine (MEA) solutions in a spray column under various operational conditions. The effects of gas flow rate (1.25–5.19 L/min), CO 2 concentration (10–40 vol%), solvent concentration (2.5–7.5 wt percent (wt.%) for NaOH; 5–25 wt% for MEA), solvent volume (0.5–1.5 L), and temperature (303–323 K) were systematically analyzed. The results show that NaOH achieves a maximum absorption efficiency of 95 % at 5 wt% concentration and the lowest gas flow rate. In comparison, MEA requires a higher concentration of 15 wt% to reach 96 % efficiency under the same conditions. Raising gas flow from 1.25 to 5.19 L/min reduced efficiency to 47 % (NaOH, 5 wt%) and 45 % (MEA, 15 wt%). Increasing solvent temperature from 303 to 323 K significantly improved MEA performance at 3.00 L/min (≈75 %→83 %), while NaOH remained ≳95 % at 1.25 L/min with minor sensitivity. These results show that, in spray columns, high capture can be achieved with relatively low solvent concentrations, implicating lower regeneration energy, reduced solvent degradation, and lower operating costs while clearly delineating operating windows for NaOH vs. MEA. • Experimental investigation of CO 2 capture using spray columns. • Comparison of sodium hydroxide and monoethanolamine as solvents. • Determination of CO 2 absorption efficiency and liquid loading. • Investigation of the effects of gas flow rate and concentration, and solvent concentration, temperature, and volume.