Abstract: The activity of the reforming catalyst SR-1000 was rapidly decreased and the octane number of the reforming gasoline was reduced because of the nitrogen poisoning of the reforming catalyst SR-1000 caused by excessive nitrogen content of the refined oil in the 450 kt/a semi-regenerative reforming unit of a refinery in October 2021. Through the systematic analysis of the reasons for the excessive nitrogen content of refined oil, it was found that the excessive nitrogen content of the refined oil was mainly caused by both the improper use of anti-corrosion neutralizing inhibitor which increased nitrogen content in the pre-hydrogenation feedstock and the low denitrification activity of pre-hydrogenation catalyst. In the practice of industrial application, such measures as selecting suitable corrosion inhibitor and controlling the injection amount, adjusting pre-hydrogenation unit reaction and operating conditions of the evaporation column, and using high-activity denitrification and pre-hydrogenation catalysts, etc. could effectively solve the problem of excessive nitrogen content in refined oil. The activity of the reforming catalyst could be recovered even if the impurity content of the refined oil was qualified.

Key words: semi-regenerative reforming, pre-hydrotreating, corrosion inhibitor, catalyst, nitrogen poisoning