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

摘要

In order to study the effect of heat-stable salts (HSSs) on the CO2 absorption performance of amine solution, the CO2 absorption/desorption rates and cyclic CO2 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 CO2 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 CO2, absorption rate and cyclic CO2 solubility, but promote the CO2 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 CO2 absorption-stripping process using amine solutions.