An insight on amine air-cooled heat exchanger tubes’ corrosion in the bulk CO2 removal plant

• The major damage was experienced within the first 20 cm of the first tube pass.
• Acid gas loading of the amine sample suggests good stripping in the stripper section.
• Carbon steel weight loss does not associate with corrosion.
• Non-uniform corrosion was attributed to the impingement force imparted by erosion.

The corrosion behavior of activated MDEA solution was investigated in the background of CO2 bulk removal in ammonia plant, Kermanshah, Iran. The visual inspection reports demonstrated a consistent pattern of damage at the tubes’ entrance of lean amine air-cooled heat exchanger, made from carbon steel. To provide information on the corrosion in tubes, a series of experiments was carried out at 85 °C, with different combinations of CO2 loading (0.02, 0.25 and 0.6 mol/mol) using electrochemical techniques, weight loss coupons, chemical analysis, and surface analytical techniques. Results showed that the dominant process was the effect of erosion corrosion. It seems that impinging particles remove the semi-protective layer of FeCO3 on the carbon steel surface, resulting in continuous exposure of fresh metal surface to the corrosive environment, and a higher corrosion rate.

(a) Air-cooled HEX and (b) the position of the damaged tube in the air-cooled HEX.Figure optionsDownload as PowerPoint slide