Abstract: To address the recurring unqualified of the copper strip corrosion test for hydrocracked light naphtha from a petrochemical company after alkanolamine desulfurization, factors influencing the copper strip corrosion performance of light naphtha were analyzed. Multiple techniques including scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), and copper strip corrosion sensitivity testing were employed to conduct an in-depth investigation into the root causes of the test failure. The results indicate that common organic sulfides and inorganic sulfur oxides within typical content ranges are not responsible for the unqualified corrosion test. The primary factor leading to the failure is elemental sulfur present in the light naphtha. The elemental sulfur is generated by the oxidation of residual hydrogen sulfide in the desulfurization alkanolamine solution upon contact with air, and it exhibits extremely high corrosion sensitivity to copper strips. When the mass fraction of elemental sulfur in light naphtha reaches 2 μg/g, the copper strip corrosion grade is determined to be 2d. Based on the research findings, the unit adopted sealing measures to isolate the alkanolamine solution from air exposure, thereby ensuring the copper strip corrosion performance of light naphtha meets the qualification criteria.

Key words: light naphtha, copper corrosion, elemental sulfur, air oxidation