Hydrodesulfurization has much attention in the hydrotreating technology; however, due to the high nitrogen heavy oil processing has become a trend, and exist of nitrides suppress the catalyst performance of deep hydrodesulfurization. Since the processing of nitrogen and offshore crude oil has a considerable proportion of China's oil refining industry, the development of low-grade nitrogen distillate deep hydrodesulfurization catalyst becomes very necessary.

 

In oil refining field, Ni, Co, Mo, W and other metals are often taken as the active component of the catalyst; tungsten trioxide can be used as an active ingredient of the desulfurization catalyst, and play a role in preventing sulfur poisoning. This paper introduces a method for preparing high nitrogen low-grade gasoline and diesel hydrodesulfurization catalyst, which takes the ternary oxide Al₂O₃-SiO₂-TiO₂ as the composite carrier, the oxides of nickel, molybdenum and tungsten as active components; also additives—phosphorus is added. 

 

The preparation process is as following:

1. Preparation of carrier: Uniformly mix the big hole intended boehmite first, partial titanate and silica, add glue solvent extrusion aid and expanding agent; and then extruded into strips, then going through health, dried at 80~200°C for 2~15 hours, calcined at 550~650°C for 1~8 hours, finally get Al₂O₃-SiO₂-TiO₂ ternary oxide composite carrier;

2. Preparation total immersion: Add the active metal salt (ammonium paratungstate, ammonium paramolybdate etc.), complexing agents and additives into the solvent--deionized water or ammonia solution in deionized water at room temperature, stir dissolve uniformly, get the stable impregnating solution and get constant volume;

3. Preparation of catalyst: The total immersion after double dilution is divided into two of the equal volume, and then the active ingredients are uniformly dispersed on the carrier by two-step impregnation method. The specific operation is that place the carrier strip in the dipping bath, add one of the two total immersion impregnation, then drying in an oven, calcined in a muffle furnace, and then cooled to room temperature; then add the another portion of total immersion, repeat the above steps to obtain the desired catalyst.