Pilot Plant Studies of the CO₂ Capture Performance of Aqueous MEA and Mixed MEA/MDEA Solvents at the University of Regina CO₂ Capture Technology Development Plant and the Boundary Dam CO₂ Capture Demonstration Plant

Abstract

Evaluations of the benefits of using a mixed MEA/MDEA solvent for CO2 capture in terms of the heat requirement for solvent regeneration, lean and rich loadings, CO2 production, and solvent stability were performed by comparing the performance of aqueous 5 kmol/m3 MEA with that of an aqueous 4:1 molar ratio MEA/MDEA blend of 5 kmol/m3 total amine concentration as a function of the operating time. The tests were performed using two pilot CO2 capture plants of the International Test Centre for CO2 Capture (ITC), which provided two different sources and compositions of flue gas. The University of Regina CO2 plant (UR unit) processes flue gas from the combustion of natural gas while the Boundary Dam CO2 plant (BD unit) processes flue gas from a coal-fired electric power station. The results show that a huge heat-duty reduction can be achieved by using a mixed MEA/MDEA solution instead of a single MEA solution in an industrial environment of a CO2 capture plant. However, this benefit is dependent on whether the chemical stability of the solvent can be maintained.