Abstract
Absorption using aqueous solutions of alkanolamines is the most widely used procedure for removal of carbon dioxide from natural gas, flue gases from power-generating facilities, and other mixtures. Its main drawback is degradation/deactivation of alkanolamine under the process conditions (high temperatures, presence of oxygen and other impurities) with the formation of heat-stable salts consisting of alkanolammonium cation and anions of organic and inorganic acids. The main operation problems caused by heat-stable salts are considered in the review. Three main methods for removal of heat-stable salts from alkanolamine adsorbents are described in detail: distillation, ion exchange, and electrodialysis. The main characteristics of these methods and their advantages and drawbacks are described, and a comparative analysis is made. The history and state-of-the art of studies within the framework of each method are presented.