Corrosion in amine solvents used for the removal of acid gases
Résumé
Processes using amine solvents for the removal of CO 2 have long been used for the treatment of natural gas. More recently, developments in the field of post-combustion CO 2 capture have gained considerable interest for greenhouse gas mitigation. Even though the nature of the amine is different for both applications, the process flow diagrams are very similar. The raw gas is contacted with the amine solvent in an absorber column, and the CO 2 is absorbed by the solvent. The rich solvent containing the CO 2 then circulates to a regenerator, where the temperature is increased to strip the CO 2. The lean solvent then returns to the absorber for a new cycle. For these processes, corrosion is known to be a major issue. Usually, amines are not corrosive but during operation of amine units, degradation of the solvent may occur due to the reaction with contaminants like oxygen. As a result, corrosive species are formed including other amines and acids products like oxalates, formates and acetates also known as Heat Stable Salts (HSS). Corrosion problems may also depend on other parameters for instance type and concentration of the alkanolamine, temperature of the solvent or CO 2 loading. In order to extend the limits of gas treating processes, but also to develop the new processes for CO 2 capture, a better understanding of corrosion in amine solvents is required. This paper presents the first results of a study where the impact of several parameters will be evaluated by electrochemical methods. The corrosivity of Monoethanolamine (MEA), Diethanolamine (DEA) and methyl-diethanolamine (MDEA) was compared. Other parameters were studied, among which the impact of CO 2 loading and the concentration in HSS. Back-2
Domaines
Matériaux
Origine : Fichiers produits par l'(les) auteur(s)
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