Further Investigation on Flow-Accelerated Corrosion under Two-Phase Flow Conditions: Effects of a Film-Forming Amine and Effects of Amine Degradation Products in the Presence of Ammonia and Ethanolamine

摘要

Experiments were carried out at simulated power plants conditions, specifically two-phase steam-water mixtures at 200°C with various steam voidages, to investigate influences of various amines on Flow-Accelerated Corrosion (FAC). A commercial film-forming amine, Cetamine, added to feedwater showed no advantage over cyclohexylamine, its associated pH agent, at the same pH_(25°C) 9.2. Thermal breakdown products of ethanolamine are acetic and formic acid. Addition of acetic acid to a mixed ammonia-ethanolamine chemistry at pH_(25°C) 9.2 significantly increased FAC rate, whereas only a marginal effect was observed under similar conditions but with ammonia chemistry. Formic acid is lost because of its low thermal stability, therefore there was no aggravating effect on FAC under the test condition.