Catalytic CO2-MEA absorptions with the aid of CaCO3, MgCO3, and BaCO3 in the batch and semi-batch processes
Three solid chemicals, CaCO3, MgCO3, and BaCO3, were tested to accelerate the CO2 absorption with monoethanolamine (MEA) solvents to verify the effect of heterogeneous catalysis. The experiments were conducted in a batch process at 20 ± 0.2 °C and a semi-batch process under room temperature. For the batch process tests, CaCO3, MgCO3, and BaCO3, accelerated the CO2 absorption with MEA solutions at 1, 3, and 5 mol/L, respectively. The overall absorption periods were reduced by around 39.5%, 36.8%, and 36.8% in 3 M solution; and 31.9%, 19.1%, and 26.6% in 5 M solution. For the semi-batch process tests, CaCO3 and MgCO3 accelerated the CO2 absorption with 5 M MEA solutions by 20% and 20%, from 57 s to 45 s to reach equilibrium at loading of 0.0 mol/mol, and 16% and 12% from 75 s to 63–66 s to reach equilibrium at loading of 0.20 mol/mol. These solid chemicals were good candidates of heterogeneous catalysts of CO2–MEA absorption in an amine scrubbing process.