Research progress of carrier in supported hydrodesulfurization catalyst

The carrier of the hydrodesulfurization catalyst is an important part of the catalyst, which is used to carry and evenly disperse the active components, providing the reaction site and play the role of skeleton support. The surface properties of the carrier and its interaction with the active metal components will affect the dispersion and sulfidity of the active metal components. For supported transition metal sulfide catalysts, the higher the dispersion, the higher the activity.It is generally believed that the interaction between the carrier and the metal component is conducive to the complete sulfurization of the active component, so the reactivity is high. 

Al2O3 is widely used as a carrier of industrial catalysts due to its good mechanical properties, regeneration properties, excellent structure and low price.However, there is a strong interaction between Al2O3 and transition metal oxides, which limits the further improvement of catalytic activity of metal active components. 

The interaction between activated carbon and metal oxide is weak,  it is easy to produce high-activity type Ⅱ Co-Mo-S phase. Most Co is octahedral. The results show that compared with the traditional Al2O3 catalyst, the catalyst supported by activated carbon has the advantages of high activity and low coking. However, activated carbon has many micropores ，which is not suitable for macromolecular catalytic reaction, while hollow activated carbon has low crushing strength and surface area.

Acidic carrier is a research hotspot at present. Among acidic carrier, TiO2, ZrO2, amorphous aluminum silicate and molecular sieve are studied most. Generally speaking, catalysts loaded on acidic carriers show high HDS activity, especially for 4-MDBT and 4,6-DMDBT, which are difficult to remove from petroleum fractions, the activity is much higher than that of Al2O3 as a carrier catalyst.

Although the catalysts prepared with TiO2 and ZrO2 as the carrier show high catalytic activity, their practical application is limited due to their small surface area and poor thermal and mechanical stability.Therefore, the mixture of them and Al2O3 as the carrier, give full play to their advantages, attracted more and more attention. It is proved that this is an economical and effective method to increase the activity of catalyst HDS.