Synergistic effect of multi heat-stable salts on corrosion in alkanolamine-based CO_2 capture unit

摘要

This work investigated synergistic corrosion effects that may exist in amine treating plants containing a mixture of heat-stable salts. The investigation was experimentally carried out in a 5 kmol/m~3 monoethanolamine (MEA) solution containing 0.20 mol/mol CO_2 loading at 80°C under atmospheric pressure using carbon steel 1018. Six heat-stable salts including formate, oxalate, bicine, acetate, thiosulfate, chloride were selected from thirteen salts and tested with a series of salt combinations. Potentiodynamic Polarization, Tafel Extrapolation, and Cyclic Polarization were used for revealing corrosion behavior, determining corrosion rate, and examining pitting tendency, respectively. A corrosion model was also developed by using a principle of statistical factorial design. The model was used for identifying the most influential salt on corrosion rate and the salt combination causing the system more corrosive.