Structural Investigation on the Thermal Degradation of Aqueous Amines in Post-Combustion CO2 Capture

One of the major issues concerning the increase in global temperature is with the elevating levels of CO2 in the atmosphere. Combustion of fossil fuels in power plants is a leading contributor to the elevated anthropogenic CO2 concentration. To help alleviate this issue, the investigation of aqueous amines being implemented for the capture of CO2 in the post-combustion carbon capture (PCCC) in power plants has been a growing interest to chemists. One of the concerns with aqueous amines, is their ability to thermally degrade. Thermal degradation is a prominent aspect for the loss of aqueous amines during the stripper process in powerplants. The focus of this research was to investigate the structural effect on the thermal degradation of aqueous amines. The method for this investigation involved the degradation of a 30 wt% amine solution loaded with a 0.4 ratio of moles CO2/moles of amine, over a one-week span at 125, 135, and 145˚C. After which, the degraded species were analyzed using high-performance liquid chromatography (HPLC) and nuclear magnetic resonance (NMR). A computational analysis using the B3LYP functional for the thermodynamics of the CO2 binding to aqueous amines was done to try and be compared to the results acquired from HPLC and NMR experimentation to help quantify the favorability of thermal degradation based on the structure of certain amines