THE STABILIZATION OF MONOETHANOLAMINE SOLUTIONS FOR SUBMARINE CARBON DIOXIDE SCRUBBERS
NAVAL RESEARCH LAB WASHINGTON DC
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Monoethanolamine MEA, the regenerative absorbent used in all CO2 scrubbers aboard nuclear submarines, is at present stabilized with a chelating agent, the monosodium salt of N, N-diethanolglycine VFS. In dynamic tests at 131F the additive, although effective in metal-free solutions, did not prevent oxidative degradation of the amine when copper was present in the concentrations usually found in scrubber solutions. Effective stabilization in the presence of copper was given by the tetrasodium salt of ethylenediaminetetraacetic acid EDTA. At 208F in the presence of several metal contaminants, a combination of VFS and EDTA was required for stabilization. Both VFS and EDTA were shown to be true antioxidants for MEA in their own right. Their reactivity with peroxides, and their prevention of peroxide formation in oxidized MEA suggested that their antioxidant activity resulted from an ability to interrupt an autocatalytic oxidation chain reaction. Less efficient additives did not prevent peroxide formation in MEA.
- Inorganic Chemistry
- Organic Chemistry