Hydrodesulphurization performance of NiW/TiO2-Al2O3 catalyst for ultra clean diesel

TiO2-Al2O3 binary oxide supports were obtained by sol–gel methods from Tetra-n-butyl-titanate and pseudoboehmite/aluminium chloride resources. The typical physico-chemical properties of NiW/TiO2-Al2O3 catalysts with different TiO2 loadings and their supports were characterized by means of BET, XRD and UV–vis DRS, etc. The BET results indicated that the specific surface areas of NiW/TiO2-Al2O3 catalysts were as higher as that over pure γ-Al2O3 support, and the pore diameters were also large. The XRD and UV–vis DRS analyzing results showed that the Ti-containing supported catalysts existed as anatase TiO2 species and the incorporation of TiO2 could adjust the interaction between support and active metal, and impelled the higher reducibility of tungsten. The hydrodesulphurization (HDS) performance of the series catalysts were evaluated with diesel feedstock in a micro-reactor unit, and the HDS results showed that NiW/TiO2-Al2O3 catalysts exhibited higher activities of ultra deep hydrodesulphurization of diesel oil than that of NiW/Al2O3 catalyst. The optimal TiO2 content of NiW/TiO2-Al2O3 catalysts was about 15 m%, and the corresponding HDS efficiency could reach to 100%. The sulphur contents of diesel products over NiW/TiO2-Al2O3 (from pseudoboehmite/AlCl3) catalysts with suitable TiO2 content could be less than 15 ppmw, which met the sulphur regulation of Euro IV specification of ultra clean diesel fuel.