Abstract: A series of γ-Al2O3 supports containing different content of sodium and successively NiMo/Al2O3 catalysts were prepared by impregnation method. The effect of Na on residue hydrotreating performance was tested using the Western Pacific atmospheric residue as feedstock. The samples were characterized by BET, IR-OH, LRS, and H2-TPR．The results show that the hydrotreating activity of the resulting catalyst is reduced with the addition of Na into γ-Al2O3. No influence on the pore structure and the acid amount of the support is observed by adding Na under the test conditions. However, the basic hydroxyl groups on the surface of the carrier increases, and the acidic hydroxyl groups decreases. The interaction between the active metal and the support is strengthened, due to the transformation of the octahedral Mo (O) species into the tetrahedral Mo (O) species, resulting in the decrease of the hydrotreating activity.

Key words: residue hydrotreating, NiMo/Al2O3 catalyst, sodium content