Abstract: Continuous corrosion leakage occurred on the wall of the drying tower in the concentrated acid area of the acid regeneration unit of an alkylation plant in a petrochemical company. To investigate its failure mechanism, systematic tests were carried out on the failed samples by means of macroscopic observation, chemical composition analysis, metallographic examination, scanning electron microscopy and energy spectrum analysis. Combined with actual process operation parameters, it is determined that excessively high operating temperature and replacement of the tower wall material are the root causes of the failure.Based on the analysis results, targeted improvement measures were formulated from two aspects: optimizing process operation and improving the corrosion resistance of materials, so as to effectively ensure the long-term safe and stable operation of the equipment.

Key words: alkylation unit, acid regeneration plant, drying tower, sulfuric acid corrosion, intergranular corrosion, ZeCor-Z, failure analysis