Hydrogenation catalysts

Hydrocarbon hydrogenation is a complex reaction system in which the reactions directly interact with each other. To improve the reaction rates and product yields of various oils in the plant, corresponding hydrotreating catalysts need to be developed. Depending on the focus of the hydrogenation reaction, hydrotreating catalysts are divided into hydrotreating catalysts and hydrocracking catalysts.

(i) Hydrotreating catalysts
1. Types of hydrotreating catalysts
There are many types of catalysts for hydrotreating, and those widely used at present include: alumina-based molybdate (Co-Mo/γ-Al2O3), alumina-based nickel molybdate (Ni-Mo/γ-Al2O3), alumina-based cobalt-molybdenum-nickel (Mo-Co-Ni/γ-Al2O3), alumina-based nickel molybdate (Ni-Mo/γ- Al2O3), and the later developed Ni-W series. Their order of activity for the various reactions is
Hydrosaturation: Pt, Pd>Ni>W-Ni> Mo-Ni> Mo-Co> W-Co.
Hydrodesulphurisation: Mo-Co> Mo-Ni> W-Ni> W-Co.
Hydrodenitrogenation: W-Ni> Mo-Ni> Mo-CO> W-Co.

2. Requirements for the use of hydrotreating catalysts
The hydroprocessing activity depends mainly on the type and content of the metal, the state of the compound and the dispersion on the surface of the carrier.
Hydrotreating catalysts are characterised by:
① Pre-sulphation is required before use to improve the activity of the catalyst and extend its service life;
② Regeneration after a period of use, where the coke deposited on the catalyst surface is burnt off under strictly controlled regeneration conditions.

(ii) Hydrocracking catalysts
Hydrocracking catalysts are dual function catalysts, i.e. the catalyst consists of a metal component with a hydrogenation function and an acidic carrier with a cracking function. The functions of these two components are appropriately selected and matched according to the different raw material and product requirements.