The corrosion failure of the scrubber tray of a petrochemical POSM device occurred during its service.The failure analysis was carried out with the corrosion tray as the object.The macroscopic inspection,chemical composition analysis,metallographic analysis,scanning electron microscopy and energy spectrum analysis,phase analysis were carried out respectively.The results show that the p-toluene sulfonic acid entrained in the gas phase at the top of the scrubber contains free sulfuric acid,which were dissolved in water and concentrated into a high concentration of sulfuric acid solution at a certain temperature,thus caused corrosion to the tray.In addition,based on the service condition of the tray,the corrosion rate of sulfuric acid to the tray material S22053 under the current operating conditions was deduced.Finally,according to the analysis results,the operation and maintenance suggestions of the scrubber were given.