JPH038445A - Production of alumina carrier - Google Patents

Abstract

PURPOSE:To efficiently obtain a catalyst for hydrogenation refining having high performance by adding an acid to a slurry consisting of alumina hydrate and water, further adding an alkali and separating alumina hydrogel, which is then kneaded, molded, dried and calcined. CONSTITUTION:Water is added and mixed with alumina hydrate to prepare a slurry having about 3% concn. of alumina. An acid is added to the slurry to adjust the pH of the slurry to 20-30 and an alkali is added to adjust the pH to 35-60. By this pH adjustment, the pore characteristics of the alumina can be regulated. Alumina hydrogel is separated from the resulting slurry with a vacuum filter, etc., dehydrated and washed to form a cake. This cake is kneaded, molded, dried and calcined to obtain an alumina carrier having superior performance in desulfurization and denitrification.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing an alumina support used as one of the supports for various catalysts, and more specifically, to a hydrorefining catalyst used in petroleum refining processes. It relates to a method for producing an alumina support which, when used, gives high activity.

[Prior Art] Various catalysts suitable for the purpose are used in various reaction processes in all fields including petroleum refining and petrochemistry.

An example in the field of petroleum refining is a hydrorefining catalyst in which active metals such as molybdenum and nickel are supported on an alumina carrier, which are widely used. In recent years, in order to flexibly handle many types of crude oil, the country's oil refineries have been increasing their
In order to meet the demands for higher quality to promote the reduction of pollution, there is an increasing demand for catalysts that have higher hydrodesulfurization activity, denitrification activity, and decomposition activity than conventional ones.

Therefore, much research has been carried out on the development of high-performance catalysts and the development of supports for producing high-performance catalysts. For example, examples of catalysts with improved desulfurization and denitrification activities in which the carrier composition contains titania, zirconia, boria, etc. as components other than alumina have been disclosed (JP-A-55-165145, JP-A-Sho. 56-133
035). In addition, there are examples of improving the activity by supporting hydrogenation metals such as molybdenum and nickel on an alumina support and then adding titania and boria to the support (Japanese Patent Laid-Open No. 53-51
205, Japanese Patent Publication No. 54-96489).

Furthermore, when producing inorganic porous materials such as alumina from aluminum salts, etc., the so-called pH is adjusted at the hydrogel preparation stage.
A technique related to a method for manufacturing carriers having various uniform pore sizes by performing a swing operation is disclosed (Japanese Patent Laid-Open No. 56
-120508). This is considered to be effective when changing pore characteristics and applying it to heavy oil processing.

[Problems to be Solved by the Invention] As described above, in the conventional technologies related to carriers and carrier components, it is possible to improve the activity of alumina by adding second and third components during the production process of alumina and catalysts. Although studies have been made to change the pore characteristics during the production process to make it suitable for heavy oil processing, no attempt has been made to produce a high-performance catalyst by processing alumina itself.

An object of the present invention is to efficiently produce a high-performance hydrorefining catalyst using alumina as a raw material, and in particular to produce an alumina carrier suitable for producing such a catalyst.

[Means for Solving the Problems] The inventors conducted intensive research to develop a technology for producing a highly active hydrorefining catalyst using alumina hydrate as a raw material, and as a result, the specific surface area and pore volume of the support were Although the physical properties of the alumina carriers are almost the same as those produced by conventional techniques, the activity of the catalysts produced therefrom is much higher than that of alumina supports made by conventional techniques. They discovered a method for producing a carrier and completed the present invention.

That is, in the present invention, (a) an acid is added to a slurry consisting of alumina hydrate and water to adjust the pH of the slurry to 2.0.
~3. (b) Then, an alkali is added to adjust the pH of the slurry to 3.5-6°0, and (c) the pH is adjusted to
The present invention provides a method for producing an alumina carrier, which comprises separating an alumina hydrogel from a slurry of 3.5 to 6.0, and (d) kneading, molding, drying, and firing the alumina hydrogel.

A conventional method for producing an alumina support and a catalyst using alumina hydrate as a raw material is as follows.

First, water is added to alumina hydrate in a kneader and kneaded.
A kneaded material to be used as a molding raw material is obtained. At this time, it is known to add an acid or alkali as appropriate for the purpose of adjusting the pore characteristics of alumina. The kneaded product thus obtained is molded into a desired shape such as a cylinder, a pellet, or a sphere using a molding machine to obtain a molded product.

The molded product is dried at a temperature of about 80 to 150°C for several hours to about a day and night, and then fired in a firing furnace at a temperature of 400 to 1000°C to obtain an alumina carrier.

Next, in order to support the active metal on the alumina support,
The active metal is impregnated in the form of a solution of the metal salt by sprinkling or immersion in the solution.

The alumina carrier impregnated with a solution such as a metal salt has a 80 to 15
After drying at a temperature of about 0℃, it is heated to 400~600℃ in a firing furnace.
The final target product, the catalyst, is obtained by firing at a temperature of about °C.

In contrast, the present invention is characterized in that an alumina hydrogel obtained by treating alumina hydrate with acid and alkali is kneaded, molded, dried, and fired to produce an alumina carrier as described above. The performance of the catalyst prepared from the alumina support produced by the method of the present invention described was significantly superior to that produced by conventional methods.

The method for producing an alumina carrier from an alumina hydrate according to the present invention will be specifically explained below.

First, water is added to alumina hydrate and stirred using a rotating blade or air blowing method to form a slurry with an alumina concentration of about 3 quartz. Acid was added to the slurry to adjust the pH to 2.
0 to 3.0. If the pH is less than 2.0, the acid and the alkali in the next operation are wasted, and if it exceeds 3.0, the sufficient effect of the present invention cannot be obtained. Next, an alkali is added to adjust the pH to 3.5 to 6.0. At this time, the pH is 3.5
If it is less than 6.0, the pore diameter of the alumina carrier obtained will be too small, and if it exceeds 6.0, the pore diameter of the alumina carrier obtained will be too large, and in either case, sufficient desulfurization and denitrification activities cannot be maintained. In particular, when the pH exceeds 6.0, the pellet strength of the resulting alumina carrier decreases, which poses a practical problem.

The alumina hydrogel is separated from the slurry thus obtained using a vacuum filter, dehydrated, and washed to obtain an alumina hydrogel cake.

Thereafter, the cake is kneaded, shaped, dried, and fired in the same manner as conventional methods to obtain the alumina carrier of the present invention. However, if the moisture content of the alumina hydrogel cake is high, molding may become difficult, and it is desirable to adjust the moisture content of the cake to a level that facilitates molding. For example, a kneaded material with a viscosity suitable for molding can be obtained by evaporating water using a kneading machine equipped with a heating device.

An active metal is supported on the alumina support obtained by the method of the present invention by a known method, and a desired catalyst can be produced through steps such as drying and calcination.

In the present invention, pseudo-boehmite alumina, vialite, gibbsite, etc. can be used as the alumina hydrate, but pseudo-boehmite alumina is particularly preferred.

Examples of acids include inorganic acids such as nitric acid, hydrochloric acid, and sulfuric acid;
An organic acid such as acid, citric acid, or acetic acid may be used. In particular, nitric acid and organic acids are more preferable because all the components are volatilized by firing and no residue is left.

As the alkali, ammonia, caustic soda, caustic potash, sodium aluminate, etc. can be used. Among them, ammonia is more preferably used because its components are volatilized by firing.

The present invention will be described in more detail below with reference to Examples.

Note that the following examples do not limit the present invention.

(Example 1) Pseudo-boehmite type alumina hydrate 600 in a 202 plastic container
15Q of deionized water at 80° C. was added and stirred to form a slurry, and 166.5 g of 61% nitric acid was added to adjust the pH of the slurry to 2.3. After stirring the slurry for 15 minutes, 92 mQ of 29% aqueous ammonia was added to adjust the pH of the slurry to 4.0. The slurry thus obtained was passed under reduced pressure to obtain an alumina hydrogel cake.

The cake was put into a kneader equipped with a heating device and kneaded and concentrated until the moisture content became about 50%, and the resulting kneaded product was extruded to obtain a cylindrical molded product with a diameter of 1.6++un. The cylindrical molded product was dried at 130°C for one day and night, and then fired at 600°C for 1 hour to obtain an alumina carrier.

Next, active metal molybdenum was added to 100 g of the alumina carrier.
In order to support nickel and phosphorus, a separately prepared support solution containing these in the form of compounds such as salts was impregnated. After drying the impregnated alumina carrier at 130°C for 1 day and night,
The mixture was calcined at 00° C. for 1 hour to produce a hydrorefining catalyst (A).

The supporting liquid was prepared by mixing and dissolving 30.4 g of ammonium rosemolybdate, 20.5 g of nickel nitrate, and 12.8 g of 85% phosphoric acid in 40 cc of deionized water.

(Comparative Example 1) 2 kg of the same pseudo-boehmite-type alumina hydrate used in Example 1 was charged into a kneader without the pretreatment characteristic of the present invention, and 65% of 61% nitric acid was added. 4g and deionized water2. OQ was added and kneaded until the kneaded material became uniform. After forming the kneaded product, a catalyst was prepared in exactly the same manner as in Example 1 to obtain a hydrorefining catalyst (B) by a conventional method.

(Comparative Example 2) A hydrorefining catalyst (C) was obtained by the conventional method in exactly the same manner as in Comparative Example 1, except that 53.3 g of 61% nitric acid was added to the kneader and kneaded for 2 hours.

Catalysts (A), (B) and (C) thus obtained
The pore characteristics of the alumina support used in the production of
Pore volume and median diameter (pore diameter at which the pore volume is 50%) are measured using the nitrogen adsorption method Digisoap 260.
0 (manufactured by Micromeritech, USA). The results are shown in Table 1.

According to Table 1, the alumina carrier of the present invention (corresponding catalyst (A)
) The physical properties of the conventional method alumina support (corresponding catalyst (B),
(C)) has a value approximately in between.

(Example 2) A hydrorefining test of the hydrorefining catalyst (A) was conducted using a flow-through high-pressure reaction test device with a catalyst filling capacity of 100 cc under the following raw oil properties and test conditions.

Mioka Sarayu Station oil type Vacuum light oil Sulfur content 2.77 Weight% Nitrogen content 1200 Weight ppm Specific gravity
0.9332 Return J and 11 Hydrogen partial pressure H3V Hydrogen/oil ratio reaction temperature (Comparative example 3) For each of the hydrorefining catalysts (B) and (C) produced in Comparative examples 1 and 2, the results were completely the same as in Example 2. A hydrorefining test was conducted using the same equipment and feedstock reaction conditions.

In this way, the sulfur content and nitrogen content contained in each product oil obtained for each catalyst (A), (B), and (C) were measured, and the desulfurization and desulfurization reaction rate constants were determined using the following formula, and the desulfurization reaction rate constant :
k (DS)・(1/5p-1/Sf door LH3V denitrification reaction rate constant: k(DN)4n(Nf/Np) furrow H5
V, however, Sf: Sulfur content in the raw material (weight %) Sp: Sulfur content in the produced oil (weight %) Nf: Nitrogen content in the raw material (weight ppm) Np: Nitrogen content in the produced oil (weight ppm) Ll (SV: volume reference space velocity (Hr-”) 80 kg/c
m2, OHr-1 400Q/α 360-400°C Relative desulfurization activity and relative desulfurization activity were determined from the ratio of these constants (with catalyst (B) being 100). The results are shown in Table 2.

Although the alumina support obtained according to Table 2 has almost the same chemical and physical properties as those made by the conventional method, the hydrorefining catalyst made from it has almost the same chemical and physical properties as those made by the conventional method. It has a remarkable effect of being far superior in desulfurization, denitrification, etc. performance than a catalyst using an alumina carrier.

Claims (1)

[Claims] (1) In a slurry consisting of alumina hydrate and water (a)
adding acid to adjust the pH of the slurry to 2.0 to 3.0;
(b) Then, by adding alkali, the pH of the slurry is
(c) the pH of 3.5 to 6.0;
A method for producing an alumina carrier, comprising: separating an alumina hydrogel from a slurry; and (d) kneading, molding, drying, and firing the alumina hydrogel.