Preparation method of bulk cobalt-molybdenum hydrodesulfurization catalyst

Abstract

The invention provides a preparation method of a bulk cobalt-molybdenum hydrodesulfurization catalyst, which comprises the following steps of: (1) synthesizing a precursor, namely adding cobalt salt into a molybdenum salt solution, heating and refluxing, and adjusting the pH value to 4.0-6.0; heating to 60 DEG C, and maintaining for 48hr to obtain bimetal oxygen clusters; (2) preparing a catalyst:mixing bimetallic-oxygen cluster powder with aluminium hydroxide dry glue powder, molding and activating to obtain the bulk hydrodesulfurization catalyst; the space structure of the bimetal-oxygen clusters obtained by using the method is a four-cap Keggin structure. Cobalt and molybdenum atoms are connected through a bridge oxygen bond Mo-O-Co, and the bond length is shown in the description, thecobalt atom is located outside the molybdenum cluster, which belongs to close contact in real sense, and the sulfurization is beneficial to the generation of an active phase. Cobalt and molybdenum atoms are more suitable, the cluster size and the cluster spacing are moderate, the activation temperature is low, the dibenzothiophene hydrodesulfurization activity is high, and the method can providetheoretical basis for the directional construction of the active phase of the hydrodesulfurization catalyst.

Description

technical field [0001] The invention relates to the petrochemical field, in particular to a preparation method of a high-activity bulk hydrodesulfurization catalyst. Background technique [0002] With the increase in the degree of heavy crude oil and the continuous enhancement of public environmental protection awareness, the pace of upgrading of clean oil standards in my country is gradually accelerating. Hydrodesulfurization is the mainstream technology for the production of ultra-low sulfur clean oil in industry. Improve the hydrodesulfurization catalyst The study of activity has received extensive attention. [0003] The current hydrodesulfurization catalysts are mainly cobalt (nickel) molybdenum (tungsten) catalysts, which can be divided into supported type and bulk type according to the presence or absence of supports. The traditional supported cobalt-molybdenum hydrodesulfurization catalyst improves the catalytic effect by increasing the contact area between the react...

AI Technical Summary

Problems solved by technology

However, the existing synthesis methods of bulk hydrodesulfurization catalysts have the following disadvantages: (1) the raw materials used are highly toxic, and their preparation is complicated, and a large amount of toxic substances will be produced during the production process, which seriously pollutes the environment; (2) the catalyst precursor The cobalt (nickel) molybdenum (tungsten) atoms in the body do not realize the real close contact; (3) The molecular structure and composition of the catalyst precursor are uncertain, which is not conducive to the study of the structure-activity relationship between the active phase and the activity of the catalyst

Therefore, from this point of view, to increase the activity of hydrodesulfurization catalysts, it is necessary to increase the content of type II "Co(Ni)-Mo(W)-S" active phase, which requires that Mo(W) , Co(Ni) atoms are in close contact as much as possible, but the preparation method provided by this patent cannot accurately obtain the molecular structure of the precursor, and cannot prove that there is a true atomic-scale close contact between the active metals

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