Formation and removal technologies of degradation products from amino absorbents in carbon capture systems

The degradation products from amino absorbents in chemical absorption carbon capture systems is considered a significant factor affecting system performance. In this paper, oxidative and thermal degradation mechanisms of absorbents are systematically investigated. Amino absorbents generate heat stable salts （HSS） such as formic acid and oxalate via free radical chain reactions under oxidative conditions. The cyclic neutral components such as 2-oxazolidone are formed through carbamate polymerization under thermal conditions in the carbon capture systems. An overview of the four removal methods for its degradation products is presented, covering their application scenarios, advantages, and current challenges. Thermal reclaiming can simultaneously remove HSS and neutral components, but its application is limited by the high amine loss rate, high energy requirements and the risk of secondary degradation. Ion exchange and electrodialysis effectively eliminate HSS through resin adsorption and ion exchange membranes, respectively. However, the regeneration process of ion exchange resins can generate a significant volume of wastewater, and membranes of electrodialysis easily trigger fouling issues. An advanced technology coupling ion exchange with electrodialysis can effectively remove HSS, reduce amine loss and improve energy reduction through employing electro-adsorption mechanisms. However, neutral components could not be removed. Future research can focus on coupling the advantages of various reclaiming methods to promote the large-scale application of online purification technology of amino absorbents.