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Typical symptoms of MEA corrosion include thinning of the equipment wall thickness, formation of pitting, cracking in the weld areas, accumulation of corrosion products, and an increase in the iron ion concentration in the system. These symptoms often occur in the high-temperature areas or at the gas-liquid interface of distillation units, and are manifested as follows: localized corrosion on the metal surface – pitting and crevice corrosion appear in areas such as reboilers and heat exchanger tubes, resulting in the formation of small holes or grooves on the metal surface; further progression can lead to perforation and leakage. Stress corrosion cracking in welds and heat-affected zones: Due to the combined effect of organic acids generated by the degradation of MEAs and the residual stresses in the system, stress corrosion cracking (SCC) can easily occur at welding joints; this phenomenon is characterized by its concealment and sudden onset. Corrosion product deposition and scaling: Iron ions react with degradation products such as formic acid and acetic acid to form insoluble salts, which accumulate in areas of low flow velocity or dead zones within the pipes as reddish-brown or black corrosion products. This affects heat transfer efficiency and exacerbates local corrosion. The color of the amine solution darkens and more foam appears: As corrosion intensifies, the concentration of iron ions in the system increases, causing the amine solution to change from colorless and transparent to brownish-yellow or even dark brown. At the same time, the accumulation of surfactants leads to an increase in foam formation, which affects the efficiency of regeneration. Increased system pressure drop and reduced heat exchange efficiency: Corrosion products clog the pipes and heat exchanger channels, leading to an increase in process pressure drop and a decline in heat exchange performance, which requires frequent cleaning or equipment replacement. Abnormalities in online monitoring indicators: The corrosion probe indicated a significantly increased corrosion rate (>0.1 mm/a); the coupon testing revealed obvious corrosion pits, and the iron ion concentration remained above 1–3 mg/L, indicating that the system is in a state of high corrosion risk.