Thermal stability of aqueous MEA with and without added NaCl or KI

“The thermal stability of aqueous MEA with and without added NaCl or KI have no significant difference, as can be seen in Fig. 7. After 5 weeks in stainless steel cylinders at 135 °C, all the four tested solutions had amine/alkalinity losses between 22 and 25%, regardless of the type of salt and salt concentration.”


Fig. 7. Amine loss over time in the five-week thermal degradation experiments with 30 wt% MEA (aq.), respectively with and without salt addition, at 135 °C. The concentrations given are corrected to CO2-free solution and error bars represent the standard error of the two parallel samples.”

“ICP-MS analysis of the end samples in the thermal degradation study shows comparable concentrations of iron (Fe), nickel (Ni), chromium (Cr) and molybdenum (Mo) in all the SAS solutions, as in aqueous 30 %wt. MEA without salt addition (Fig. 8). Only the 7.5 %wt. NaCl SAS shows a significantly higher iron concentration than the other solutions. This indicates that the 2.0 %wt. SAS solutions do not influence the corrosivity of MEA. As a comparison, a cylinder that contained just deionized water was also subjected to thermal degradation conditions for five weeks, and close to no dissolved metals could be detected by ICP-MS.”


Fig. 8. Average metal concentration in the two parallel samples analyzed after 5 weeks of thermal degradation by ICP-MS. Error bars represent the average relative standard deviation of the analyses.”


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