Objective The aim is to analyze the causes for the frequent abnormal rise of reactor pressure difference during hydrogenation evaluation test and put forward countermeasures.

Methods X-ray fluorescence spectrometer (XRF), plasma spectrometer (ICP-OES), X-ray diffractometer (XRD) and other advanced instrument characterization and oil analysis methods were used to analyze the mud, raw oil and catalyst.

Results (1) The top of the catalyst bed was full of mud, and the catalyst agglomerated in severe cases, which was the direct cause for the abnormal rise of pressure difference. (2) The mud was rich in elements such as Zn and Fe. (3) The pollution was more serious when the straight-run kerosene or diesel was stored in galvanized iron barrel, especially for the naphthenic straight-run diesel with high acid value and low viscosity, and the Zn mass fraction exceeded 100 μg/g in short time, which was the fundamental cause for the abnormal rise of reactor pressure difference.

Conclusions (1) For different petroleum fractions, suitable storage containers should be selected for sampling. (2) The storage container should be replaced in time and the independent hydrogenation protection section, demetallization section should be set for contaminated oil products during the evaluation test. (3) Special attention should be paid to the corrosion protection of acid-containing crude oil and its fractions during processing, especially naphthenic high-acid crude oil and its distillate.