Abstract: Taking five fixed-bed residue hydrotreating units, A, B, C, D, and E, as the subjects, an investigation was conducted into the causes of radial temperature differences in the catalyst beds of these units. The results show that the factors that affect the flow distribution in the fixed bed residue hydrotreating catalyst bed include inlet distributor, catalyst characteristics and loading efficiency, liquid-phase fluid viscosity, and flow direction. After switching to a high-efficiency distributor in the second run of Unit A, the maximum radial temperature difference of the 1st reactor was lower than that in the first run when the feedstock properties were inferior. After strict control of catalyst loading quality in the third run of Unit B, the maximum radial temperature difference of the 1st reactor was basically the same as that in the second run when the raw material properties were inferior compared to the second run. As the viscosity of the liquid-phase fluid decreases, The maximum radial temperature difference between the catalyst beds of four reactors connected in series in Unit C decreases sequentially. Despite the inferior characteristics of the feedstock, the maximum radial temperature difference between the catalyst beds of the two 1st reactors (trickle bed reactor) in Unit E is lower than that of the catalyst bed of the 1st reactor(up-flow reactor) in Unit D. In response to the relatively stable and unstable radial temperature difference during the operation of the fixed-bed residue hydrotreating unit, countermeasures are proposed. If it seriously affects the operation of the unit, the introduction of FCC light cycle oil online cleaning can also be considered.

Key words: fixed bed, residue hydrotreating, catalyst bed, radial temperature difference