Abstract: The 1.2 Mt/a coker gasoline hydrogenation unit of SINOPEC Zhenhai Refining and Chemical Company was reformed to process C₅ raffinate with high diene content. The abnormal conditions such as no temperature rise in the pre-hydrogenation reactor (R200) of C₅ raffinate and the increase of diene content in the reaction product were analyzed. The initial judgment was that the impurities such as DMF and DEA in the raw material caused the reversible deactivation of the catalyst. The thermodynamics of DMF hydrolysis reaction, the reaction of DEA and hydrogen sulfide were analyzed and verified by experiments. The results showed that the impurities in the reaction system such as DMF and DEA could cause the reversible deactivation of the catalyst. According to the test results, the corresponding measures were put forward to restore the normal operation of the unit.

Key words: C₅ raffinate, hydrogenation, thermodynamics, side reaction