Corrosion Behavior of Carbon Capture Nonaqueous Solvent Compared to Monoethanolamine

A nonaqueous solvent (NAS) was developed for point-source carbon capture. This fluid utilizes a unique amine with a diluent that significantly improves specific reboiler heat duty. The corrosion rates of the new solvent in both vapor and liquid phases were evaluated in the laboratory under various conditions pertinent to carbon capture operations. The results were compared to those of a 30% monoethanolamine (MEA) solution under identical conditions. Laboratory experiments revealed that the NAS solvent is less corrosive than 30% MEA, particularly in the presence of oxygen (~0.05 mm/year in NAS vs. ~0.36 mm/year in MEA for C 1018 at 90 °C). The NAS solvent exhibits negligible corrosivity in the presence of the equilibrium amount of CO2 at lower temperatures, such as 40°C, which is approximately the operational temperature of the absorber. However, NAS corrosivity increases at higher temperatures, though it remains significantly lower than that of 30% MEA, especially for carbon steel. The corrosion rate of NAS is comparable to that of 30% MEA under continuous CO2 purging at high temperatures, such as 90°C. Based on these findings, many components of the capture plant can be constructed using carbon steel when employing NAS.