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

Evaluations of the benefits of using a mixed MEA/MDEA solvent for CO ₂ 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.