Research on the mechanism of corrosion failure in trays of a condensate stripping tower

As the core component of acid water treatment systems in the coal chemical industry, the operation stability of the condensate stripper is directly related to the safety of the device and the efficiency of resource recovery. In light of the serious corrosion problems in the tray and cylinder of a condensate stripper found after only one year of operation, the corrosion products were characterized by macroscopic and microscopic morphological observation, chemical composition analysis and phase composition tests. By combining these results with the physical properties of the reflux liquid of the stripping tower, a mechanism for tray corrosion failure is proposed. The results show that the corrosive medium in the reflux liquid is highly concentrated, with the concentration of cyanide ions being 1.78 mmol/L and the concentration of NH₃-N reaching as high as 1408 mmol/L. The trays have extensive perforations and dense corrosion pits, and the metal surface exhibits a typical scouring groove morphology. The corrosion products are mainly blue-green in color, and consist mainly of ferric ferrocyanide (Fe₄[Fe(CN)₆]₃). The main steps in the mechanism of tray corrosion failure were identified. The accumulation of an acidic medium caused by the reflux system leads to electrochemical corrosion, while the high-speed gas-liquid two-phase flow inside the tower continuously washes the metal surface. The combined effect of these two factors results in severe failure of the equipment within a short period of time. Based on the above analysis, targeted protective measures were proposed for process control and material protection. This work provides a reference for incorporating anti-corrosion features into similar equipment.