Abstract: The successful application of the RG series guard catalysts grading system in a high acid naphthenic VGO hydrocracking unit of CNOOC Huizhou Petrochemical Company Limited was introduced. The results of the operation for more than one year showed that the RG series guard catalyst system could remove and uptake the impurities, and effectively delay the rise of pressure difference of guard catalyst bed and total pressure difference of reactor. Besides, RG series catalysts exhibited certain refining activities, which shared a part of desulfurization and denitrogenation of the second fining catalyst bed and had a close function to the imported protective catalyst system. In summary, the industrial application results showed that the domestic grading guard catalyst could replace the imported protective agents, and be used with imported main catalysts of the hydrocracking unit.

Key words: hydrocracking, catalyst grading, guard catalyst