Prospects for Membrane Deoxygenation of Alkanolamine CO2 Solvents to Prevent Their Degradation (A Minireview)

Abstract

Absorption by aqueous solutions of alkanolamines is the most mature technology for removing carbon dioxide (СО2) from natural gas, off-gases from power engineering, and other mixtures. The possible presence of oxygen in the gas mixture being treated or air leakage into the absorption treatment system leads to oxidative degradation of the amine and deactivation of the absorption liquid with the formation of a wide range of corrosion-active degradation products. The paper discusses modern views on the effect of dissolved oxygen on the degradation of amine solvents. The main methods for preventing oxidative degradation of alkanolamines and fighting against it are described. Direct removal of oxygen (deoxygenation) from absorption liquids in compact and modular membrane gas–liquid contactors is suggested as an alternative countermeasure. The retrospective and state-of-the-art of membrane deoxygenation of aqueous media are presented. Advanced studies in the field of oxygen removal from amine СО2 solvents used for flue gas treatment are described.

Handling heat‐stable salts in post‐combustion CO2 capture: A detailed survey

“…Because HSS anions have chelating properties, an increase in HSS concentration can make amine absorbing solvents more corrosive. This, in turn, causes the pH of the solution to drop and its electrical conductivity to rise, which damages the protective coating on metal surfaces within the PCC system, as previously mentioned in this article 15,87–88 . Additionally, iron and chromium ions generated from equipment corrosion can reduce the thicknesses of pipes and equipment, increasing current densities on the anodic sites, and necessitating frequent filter replacements 89–91 .…”

“…This, in turn, causes the pH of the solution to drop and its electrical conductivity to rise, which damages the protective coating on metal surfaces within the PCC system, as previously mentioned in this article. 15,[87][88] Additionally, iron and chromium ions generated from equipment corrosion can reduce the thicknesses of pipes and equipment, increasing current densities on the anodic sites, and necessitating frequent filter replacements. [89][90][91] According to Rooney and Bacon, 92 the overall HSS amount should be maintained around 0.5% of the total solution.…”

Membranes Based on PTMSP/PVTMS Blends for Membrane Contactor Applications

“…Composition and kinetic diameters of gas molecules that make up a typical flue gas of a coal-fired power plant [7]. Membrane technologies are promising alternatives for separation tasks in the field of CCS [19], and, in particular, for the removal of O 2 from an aqueous media [20], due to a high energy efficiency, compactness, and modularity. For example, Liqui-Cel ® (3M) membrane contactors based on hydrophobic porous polypropylene hollow fiber membranes are successfully used to remove O 2 and other gases from water [21][22][23][24][25].…”