Effect of heat-stable salts on absorption/desorption performance of aqueous monoethanolamine (MEA) solution during carbon dioxide capture process

In order to study the effect of heat-stable salts (HSSs) on the CO 2 absorption performance of amine solution, the CO 2 absorption/desorption rates and cyclic CO 2 capacity of 30 wt% (monoethanolamine) MEA solutions in the presence of various acidic degradation products were comprehensively investigated systematically by an improved rate-based screening method. In addition, the initial pH values and CO 2 equilibrium solubility were also evaluated. These acidic degradation products considered were formic acid , acetic acid, propionic acid , butyric acid , glycolic acid, oxalic acid , lactic acid, malonic acid and bicine. The experimental results indicated that the carboxylic acids with different chemical structures can reduce the initial pH values, equilibrium solubility of CO 2 , absorption rate and cyclic CO 2 solubility, but promote the CO 2 desorption rate of aqueous MEA solution. Furthermore, a countermeasure was proposed to maintain absorption performance and reduce the energy requirement of solvent regeneration for an MEA amine-treating unit. The obtained results can provide a guidance for developing corresponding countermeasure for heat-stable salts control and removal in the CO 2 absorption-stripping process using amine solutions.