Hydrofining of Coal Tar Light Oil to Produce High Octane Gasoline Blending Components over γ-Al2O3- and η-Al2O3-Supported Catalysts

The effectiveness and suitability for hydroconyersion of coal tar light oil (CTLO), a byproduct from the coal chemical industry, were studied over gamma-Al2O3- and eta-Al2O3-supported Ni-Mo and Co-Mo catalysts in a continuous fixed-bed reactor: This work focused on eliminating sulfur-, nitrogen-, and oxygen-containing heterocycles with a smaller loss of octane number and producing high octane gasoline blending components (HOGB) with high value. Ni-Mo catalysts showed better hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) activity than that of Co-Mo catalysts. hi addition to active metal components, the overall performance of the catalyst was also closely associated with the type of support. Higher density of medium strength acid sites, better dispersion of active components, and weaker metal support interaction jointly contributed to the higher activity of eta-Al2O3 supported catalysts. Compared with gamma-Al2O3, eta-Al2O3-supported catalysts possessed more octahedrally coordinated Mo species, thus more highly active type II Co(Ni)-Mo-S phase was formed. It was encouraging to see that the sulfur content (8.3 ppm) and bromine value (0.24 g Br/100 g) of the product were meeting the Euro V Standard over NiMo/eta-Al2O3 under the experimental conditions. Moreover, the octane number of the product reached up to 100.7 in spite of a larger octane number loss during the hydroprocessing of CTLO.