New Amines for CO₂ Capture. I. Mechanisms of Amine Degradation in the Presence of CO₂

Abstract

Degradation of 12 different amines with CO2 was evaluated in 100 mL stainless steel batch reactors for 15 days at 140 °C using a 4 mol·kg−1 amine solution and a CO2 pressure of 2 MPa. At the end of the run, most of degradation products were identified by gas chromatography (GC)/mass spectrometry (MS); amounts of starting amine and its degradation products were determined with a quantitative GC method. This work compares the degradation of ethanolamines (including MEA) having one or two hydroxyl groups with the degradation of ethylenediamines. They were chosen to establish relationships between amine structure and stability properties: replacement of one alcohol function by one amine function, effect of amine function nature, impact of steric hindrance and cyclic structure. Significant differences were observed. The main degradation products are described, and some mechanisms are proposed to explain their formation.

Extensive dataset for oxidative degradation of ethanolamine at 55–75°C and oxygen concentrations from 6 to 98%

“…Degradation as a result of temperature only occurs at very high temperatures. Lepaumier observed little degradation at 140 °C in the absence of CO2 (Lepaumier et al 2009a). Formation of certain degradation compounds in the high temperature parts of the process could also contribute to formation of other degradation compounds in the absorber section acting as intermediates.…”

“…It is therefore important to consider these issues at early stage. Lately there have been several systematic degradation studies conducted to review how molecular structure influences different types of degradation (Lepaumier et al 2009a(Lepaumier et al , 2009b(Lepaumier et al , 2010Eide-Haugmo 2011;Vevelstad et al 2013a). …”

“…There is thus a need for conducting well-controlled degradation experiment in the laboratory at specific conditions to understand the formation of many of these compounds. Such earlier experiments have resulted in improved understanding of the formation mechanism of several of the compounds formed, especially the carbamate polymerization products (Lepaumier et al 2009a). The formation mechanisms for the oxidative degradation compounds are more difficult to reveal since the starting point is normally thought to be a radical mechanism, and since no studies has been performed to verify whether a hydrogen or electron abstraction mechanism dominates.…”

Technoeconomic Evaluation of MEA versus Mixed Amines for CO2 Removal at Near-Commercial Scale at Duke Energy Gibson 3 Plant

“…activated carbon, ion exchange resins, desiccants) were based on professional experience and data found on vendor websites on prevailing prices. Estimates for amine were based on MEA degradation rates using data from Singh, et al; 15 relative degradation rates for MEA and MDEA relative to MEA were extrapolated from published experiments by Lepaumier et al for aqueous amines at 140 C and high pressures of O 2 and CO 2 , 16 and also based on feedback from Huaneng.…”

Oxidative degradation of amines using a closed batch system

“…The last decade several systematic degradation studies have been performed. Thermal degradation with CO2 was studied by Davies, Lepaumier and Eide-Haugmo (Davis, 2009;Eide-Haugmo, 2011;Lepaumier et al, 2009a) and oxidative degradation by Lepaumier (Lepaumier et al, 2009b). Increased attention on oxidative degradation was seen after pilot plant samples showed high degree of similarity to degradation compounds found in oxidative degradation experiments (da Silva et al, 2012;Lepaumier et al, 2011a;Strazisar et al, 2003).…”