JPS6312659B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an alumina carrier having suitable performance as a carrier for a hydrodesulfurization catalyst. Atmospheric residual oil, vacuum gas oil, vacuum residual oil, etc. produced by distilling crude oil under atmospheric pressure or reduced pressure. The so-called petroleum heavy hydrocarbons often contain large amounts of sulfur compounds, and the content is
Although it varies depending on the type of crude oil, it usually amounts to several percent when converted to elemental sulfur. When these petroleum heavy hydrocarbons are used as fuel, they generate harmful substances such as sulfur dioxide gas, corrode combustion furnaces, and pollute the atmosphere. Together with impurities such as metals, it deactivates the catalyst and is a major cause of hindering operations for effectively utilizing heavy hydrocarbon components. For this purpose, petroleum heavy hydrocarbons containing large amounts of sulfur compounds are supported on alumina or on alumina containing a small amount of silica, with metal components of group B metals of the periodic table, such as molybdenum, and group metals such as cobalt and/or nickel. Although an operation for removing sulfur compounds by contacting the prepared catalyst with hydrogen under pressure has been carried out industrially, a sufficiently satisfactory result has not yet been obtained. That is, the catalyst is inhibited by asphaltenes and metals present in petroleum heavy hydrocarbons, resulting in a significant decrease in desulfurization activity, and as a result, a sufficient desulfurization rate cannot be obtained. Further reductions in sulfur content require the development of improved desulfurization methods, and in particular improved hydrodesulfurization catalysts. When removing sulfur compounds contained in a fraction with a large average molecular weight such as heavy hydrocarbon oil, the inventors used a catalyst with a large number of macropores, that is, mercury intrusion method, to remove sulfur compounds with a pore radius of 37.5 Å or more. It has been recognized that a carrier having a large pore volume occupied by is advantageous. However, in general, a molded body having a desirable pore structure is characterized by a decrease in physical strength.
If the physical strength is low, the shaped catalyst will be damaged when used in a fixed bed under hydrodesulfurization conditions.
This results in the disadvantage of increased pressure loss within the reaction tower. For this reason, it is desirable that the strength of the molded body be as high as possible. As a result of our earnest efforts to develop the most effective hydrodesulfurization catalyst for heavy hydrocarbon oil, the inventors mixed boehmite with an aqueous organic polymer solution under specific conditions, molded the resulting mixture, and created the following product. We have discovered a method for producing a catalyst carrier that has a large number of macropores and has high physical strength by drying and firing a molded body. Therefore, an object of the present invention is to provide a method for producing an alumina support having suitable performance as a hydrodesulfurization catalyst. According to the invention, boehmite is mixed with an aqueous organic polymer solution. Boehmite can be produced by various industrial methods. A preferred source is boehmite, which is produced from the hydrolysis of aluminum alkoxides. The organic polymer consists of one or a mixture of polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropylcellulose and methylcellulose. Among them, polyvinyl alcohol is preferred. The organic polymer preferably has a molecular weight of 10,000 or more, and ranges from 0.5% to 10% by weight of the dry weight of boehmite (Al ₂ O ₃ H ₂ O).
A range of weight percentages is used. If the amount is less than 0.5 weight percent, the effect will not be significant for the purposes of the present invention, and even if it is used more than 10 weight percent, no effect commensurate with the increase in the amount used can be expected. The amount of water used to prepare the organic polymer aqueous solution is 120% by weight based on the dry weight of boehmite.
155% by weight. If the amount of water used is less than 120% by weight, the purpose of the present invention is not met, and if the amount of water used is more than 155% by weight, the strength of the alumina support finally obtained is undesirable. It is preferable to use an apparatus that can perform the mixing of boehmite and the organic polymer aqueous solution while providing a high shearing effect. For example, a device commonly called a double-arm kneader is preferably used. This device performs kneading by rotating two parallel mixing blades with twists, creating a shearing effect between the rotating mixing blades and between the mixing blade and the side wall. Can be implemented. The degree of mixing is indicated by the amount of power input. In order to achieve the objectives of the invention, a total energy input of between 5 and 20 Watt hours per 1000 g dry weight of boehmite should be carried out. Although energy inputs of less than 5 watt hours are converted into moldable agglomerates, alumina supports with a large number of macropores are not obtained. In addition, physical strength decreases when energy input exceeds 20 watt hours. The mixture of boehmite and the organic polymer aqueous solution is formed into any shape such as a cylinder or a sphere. The molded body is dried and fired. Drying is usually carried out at 100°C to 200°C for about 1 hour to 24 hours. Firing at 500℃~800℃ for about 2
Conducted for ~10 hours. The hydrodesulfurization catalyst comprising an alumina support obtained according to the present invention contains a catalytically active group B metal and a group metal of the periodic table. Group B metals are typically molybdenum and Group B metals are typically cobalt and/or nickel. These components may be supported on the alumina support in any manner using appropriate precursor compounds, such as ammonium paramolybdate for molybdenum, cobalt nitrate for cobalt, and nickel nitrate for nickel. For example, the alumina support obtained by the above-described production method can be immersed simultaneously or separately in an aqueous solution of a group b metal and a suitable precursor compound of a group metal, dried and calcined. According to the present invention, a carrier suitable for preparing a hydrodesulfurization catalyst having high activity and high strength can be produced. Next, the present invention will be explained with reference to Examples, but these Examples are not intended to limit the present invention. Example 1 300 g of boehmite powder corresponding to a dry weight of 273 g
384 g of an aqueous solution containing 9 g of polyvinyl alcohol with a molecular weight of 60,000 was injected at appropriate times until the total power input was 19 W hours, and the resulting mixture was molded using a screw extruder with a diameter of 1.5 mm.
It was extruded to a length of 5 mm. The molded body is heated to 120℃
After drying for a period of time, it was calcined in an air stream at 600°C for 3 hours to obtain carrier A. Example 2 300g of the same boehmite powder used in Example 1
354 g of an aqueous solution containing 9 g of polyvinyl alcohol with a molecular weight of 60,000 was injected at appropriate times until the total power input was 17.1 W hours, and the resulting mixture was molded using a screw extruder with a diameter of 1.5 mm.
It was extruded to a length of 5 mm. The molded body is heated to 120℃
After drying for a period of time, it was calcined in an air stream at 600°C for 3 hours to obtain carrier B. Comparative Example 1 300g of the same boehmite powder used in Example 1
345.5 g of an aqueous solution in which 0.5 g of polyvinyl alcohol with a molecular weight of 60,000 was dissolved was injected at appropriate times and mixed until the total power input was 11 watt hours.
It was extruded to a length of 5 mm. The molded body is heated to 120℃
After drying for a period of time, it was calcined at 600° C. for 3 hours in an air stream to obtain a carrier C. Comparative Example 2 300g of the same boehmite powder used in Example 1
The total power input was 9 while injecting 349g of water at the appropriate time.
The resulting mixture was extruded to a diameter of 1.5 mm and a length of 5 mm using a screw extruder. The molded body was dried at 120° C. for 3 hours and then fired at 600° C. for 3 hours in an air stream to obtain carrier D. The physical properties of carriers A, B, C and D were determined and are shown in Table 1. The mode pore radius and pore volume were measured by mercury intrusion method. The strength was determined by measuring the compressive strength in the radial direction using a Kiya type hardness tester.

[Table] Preparation Example of Catalyst The alumina carrier A obtained in Example 1 was immersed in an aqueous ammonium paramolybdate solution for 12 hours, separated, dried at 120°C for 3 hours, and then calcined at 600°C in an air stream for 3 hours. The obtained calcined product was immersed in an aqueous cobalt nitrate solution for 12 hours, separated, dried at 120°C for 3 hours, and then calcined in an air stream at 600°C for 3 hours to obtain a hydrodesulfurization catalyst. The hydrodesulfurization catalyst contains molybdenum 8.9
weight percent and 3.0 weight percent cobalt. Using the hydrodesulfurization catalyst, Arabian light heavy oil was treated in a small fixed-bed high-pressure flow reactor. The processing conditions are: catalyst amount 100ml, temperature
360℃, pressure 130Kg/cm ² G, LHSV0.6h ^-1 , hydrogen/
The oil ratio was 1100Nm ³ /Kl, and the catalyst was sulfurized before use. Table 2 shows the properties of the raw oil and treated oil.

【table】

Claims (1)

[Claims] 1. In the production of a carrier for a hydrodesulfurization catalyst, which comprises mixing boehmite with an aqueous organic polymer solution, molding the resulting mixture, and then drying and calcining the resulting molded product (I. ) The organic polymer is composed of one or a mixture of polyvinyl alcohol, polyvinylpyrrolidone, hydroxypropylcellulose and methylcellulose, and (b) the amount of the organic polymer is based on the dry weight of boehmite.
0.5% to 10% by weight; (c) The mixture contains 5% by weight per 100g of boehmite used.
A method for producing a support for a hydrodesulfurization catalyst, characterized in that it is carried out with a total energy input of ~20 Watt hours.