Analysis of the Regeneration of Monoethanolamine Aqueous Solutions by Microwave Irradiation

Abstract

Even if numerous studies were published over the last decades about the CO2 capture process by aqueous amine solutions, only one paper was found so far in the literature concerning the use of microwave (MW) to regenerate the spent solutions. The present work was then performed to investigate the regeneration efficiency of MEA aqueous solutions by MW while testing various amine concentrations including the well-known 30 wt%. Stripped CO2 quantities were compared to the MW energy absorbed by the solution to find the optimal regeneration conditions. The heating rate of solutions by MW was found to be influenced by their heat capacity and viscosity, two parameters with opposing effects giving rise to a maximal heating rate for concentrations of 50-60 wt% MEA. By performing absorption and regeneration cycles, the cyclic CO2 capacity of each solution was found and compared to the amount of MW energy absorbed by the solution during the stripping step. The lowest energy per mole of stripped CO2 ratio was found for the 50 wt% MEA solution which ratio is 33 % lower than the value found for the benchmark 30 wt% MEA.