JPH0459246B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to a method for producing porous alumina phospheres. [Description of the Prior Art] Many porous materials are used as carriers for various catalysts in the chemical industry, and the physical properties of these carriers are particularly sensitive to the pore volume, pore diameter, and pore distribution of the carrier. It is well known that the pore structure has a significant effect on catalyst performance such as activity, selectivity, lifetime, and strength of the catalyst. For this reason, various manufacturing methods have been proposed for controlling the pore structure of various porous materials. Regarding porous alumina phospheres, which are the subject of the present invention, attempts have been made to control the pore structure for the same purpose, and various methods for producing porous alumina phospheres have been proposed. . For example, in Japanese Patent Application Laid-Open No. 59-152262, 0.5 to 5 weight percent of P ₂ is added to an alumina carrier.
A method for obtaining a carrier with a large specific surface area and high mechanical strength by uniformly containing O ₅ is disclosed. Also, USP3271299 and
In USP 3,342,750, aluminum phosphate hydrogel obtained by reacting aluminum chloride and phosphoric acid with ethylene oxide or ammonia is extracted with a water-soluble organic solvent such as alcohol or ketone to remove water. The aluminum phosphate gel obtained is thermally stable and
It is also disclosed that it has a high specific surface area of 200 to 600 m ² /g. In USP 3904550, alumina/alumina phosphoric acid produced by hydrolyzing aluminum alkoxide with a phosphorus-containing aqueous solution has a high surface area and a uniform pore distribution. It is also disclosed that it is effective as a hydrodeaeration catalyst. Furthermore, as a similar method using aluminum alkoxide as a raw material, USP 4,233,184 discloses that a mixture of aluminum alkoxide and an organic phosphate is reacted in the presence of humid air to obtain a carrier with a large specific surface area. has been done. In the above-mentioned method, a method for manufacturing alumina phosphere or alumina phosphoric acid that has a high specific surface area, is thermally stable, and has high mechanical strength is disclosed; There is no teaching as to how to control the pore size of the pore size. In addition to the methods described above, another important method for producing alumina phosphere is a method of co-precipitating aluminum ions and phosphate ions. Similarly, various proposals have been made regarding this manufacturing method. For example, JP-A-57-135705
In the publication and the specification of USP 4,364,854, a concentrated mixture is prepared from a concentrated solution containing an aluminum salt and a phosphate ion source in a concentrated state, aluminum ions and phosphate ions are co-precipitated at a pH of 5 or higher, and this is further mixed with an organic solvent. A method for producing alumina phosphere by dehydration is disclosed, and the carrier produced by this method has high porosity and great physical strength, and is superior to chromium-based olefin polymerization. It is disclosed that it is an excellent catalyst carrier. On the other hand, in USP 4080311, when producing alumina phosphere by coprecipitating aluminum cations and phosphate anions, the pH is 7 to
It is adjusted to 10. The alumina phosphere support obtained in this way is thermally stable and
It has a specific surface area of ~200m ² /g and an average pore radius of
It is disclosed that it is controlled within the range of 75 to 150〓. In addition, in USP 4066572 specification,
Alkaline PH for compounds containing aluminum and phosphorus
A method for obtaining an alumina-phosphate gel having a large average pore diameter and in which the pore volume of 100 Å or less accounts for 30% or less of the total pore volume is disclosed. . Furthermore, according to USP 3,879,310, during the production of pseudo-boehmite, which is the precipitation of aluminum hydroxide, by adding 1 to 20 weight percent of phosphoric acid or co-precipitating, the surface of pseudo-boehmite particles is thermally stable alumina.
Obtaining phosphoric acid is disclosed. The method described above is characterized by producing alumina phosphere by co-precipitating aluminum ions and phosphate ions through a neutralization reaction. By controlling the conditions during coprecipitation, the average pore diameter of the alumina-phosphere carrier can be controlled, and a carrier that is thermally stable and has high mechanical strength can be produced. however,
Even with these methods of controlling the pore structure of alumina/phosphere, the only thing that can be freely controlled is the size of the average pore diameter, and even if the average pore diameter is the same, the pore distribution may be sharp. It can be hot or broad. On the other hand, an excellent catalyst support used in various chemical reactions needs to have a large number of pores that are optimal for each reaction. Therefore, when producing a catalyst carrier, simply controlling the average pore diameter is not a fully satisfactory production method. Therefore, it is desired to develop a manufacturing method that can control the average pore diameter within a range suitable for each chemical reaction and maintain a sharp pore distribution. [Object of the present invention] The object of the present invention is to control the pore diameter, which is difficult to produce using the conventional method.
It is an object of the present invention to provide a method for producing an alumina phosphere having a sharp pore distribution and a large pore volume and excellent mechanical strength by a simple operation. Furthermore, another object is to provide a heavy oil hydrotreating catalyst using the alumina phosphere produced according to the present invention as a carrier. [Structure of the present invention] In the production of alumina phosphere, the present invention first generates aluminum hydroxide gel from an aluminum compound, and then adds a phosphorus compound to this aluminum hydroxide gel and matures it to form a composite. The purpose is to obtain a porous alumina phosphor with a controlled pore structure. The present invention will be explained in detail below. The aluminum hydroxide gel used in the present invention can be produced by a conventionally known method. For example, a method of neutralizing an acid or base containing aluminum, a method of producing by hydrolyzing aluminum alkoxide, etc. are employed. The aluminum hydroxide gel produced by this method is
Usually, it is an amorphous or pseudo-boehmite, or a collection of fine particles exhibiting a crystalline structure such as boehmite. In order for porous alumina to have a sharp pore distribution, it is necessary that the fine particles have a uniform size, and for this purpose, various conventionally known methods can be used. For example, methods that strictly control the pH or stirring conditions during precipitation, homogeneous precipitation methods using urea, hexamethylenetetraamine, etc., PH swing methods,
Alternatively, a method of heating and kneading the generated precipitate, aging it, etc. can be adopted. It is preferable that the aluminum hydroxide gel used in the present invention has a uniform particle size as produced by the method described above, and the fine particles constituting the precipitate are not strongly aggregated. This is because in the subsequent step of adding a phosphorus compound and aging, the particle size and agglomerated state characteristics of the aluminum hydroxide gel are inherited as they are.
This is because it affects the pore structure of the carrier. In particular, if the particle size of the aluminum hydroxide gel used is non-uniform or strongly aggregated, the pore distribution of the resulting alumina phosphere will become broad after aging. As a result, macropores are present and the mechanical strength becomes weak. In the case of the present invention, in order to control the pore structure of alumina phosphere, an aluminum hydroxide gel is first produced, and then a phosphorus compound is added to it and aged. Factors are phosphorus addition amount, temperature, time, and PH. In the present invention, the amount of phosphorus added to aluminum can be set in a very wide range of 0.3 to 30 in terms of Al/P atomic ratio. The larger the amount of phosphorus added, the larger the pore diameter of the alumina phosphere. The phosphorus compound may be anything that can supply phosphate ions, such as phosphoric acid, ammonium phosphate, sodium phosphate, potassium phosphate, sodium hydrogen phosphate, potassium hydrogen phosphate, aluminum phosphate, etc. Can be mentioned. The aging temperature is preferably in the range of 50 to 100°C. Ripening temperature is 50
If the temperature is below ℃, the combination of aluminum hydroxide and phosphorus will not proceed quickly, and if the temperature is higher than 100℃, especially 120℃ or higher, alumina
Crystallization of the phosphere progresses to produce crystalline aluminophosphate, which is undesirable. The aging time is a reaction time for progressing the compounding of aluminum hydroxide and phosphorus, and the length of this time affects the size of the pore diameter of the alumina phosphere. Therefore, the aging time may be within a range preferred for industrial production, and in the method of the present invention may be within a range of 5 minutes to 24 hours. Further, it is preferable that the pH condition during ripening is maintained at 7 or less. Aluminum hydroxide particles become electron-charged in the acidic region. As a result, weak aggregation is dissociated or mutual aggregation of particles is prevented, which is very effective for obtaining a sharp pore distribution. However, in aging under acidic conditions, there is no problem when aluminum hydroxide with a large particle size is used, but care must be taken when using a small particle size of aluminum hydroxide. The phosphorus compound to be added is strongly acidic like phosphoric acid, and the amount added is large.
If the pH value is small, such as 2 or 1 or less, or if the product is aged for a long time, small aluminum hydroxide particles will dissolve and no longer form a precipitate. In such cases, add weakly acidic ammonium phosphate or sodium phosphate, or
There is no problem if you use an alkali such as ammonia to adjust the pH to a range of 3 to 7. Furthermore, when using ammonium phosphate or sodium phosphate, which are alkaline, it is preferable to adjust the pH to acidic with hydrochloric acid, nitric acid, phosphoric acid, or the like. Impurities contained in the alumina hydroxide gel are generally removed by washing, and this washing operation is performed after the aluminum hydroxide gel is formed or during the aging process. In this case, H ₃ PO ₄ ,
For substances such as (NH ₄ )H ₂ PO ₄ , (NH ₄ ) ₂ HPO ₄ , (NH ₄ ) ₃ PO ₄ that do not leave any components other than phosphere after the calcination operation, after the aluminum hydroxide gel is formed, It is preferable to do so. but,
Na ₃ PO ₄ , Na ₂ HPO ₄ , NaH ₂ PO ₄ , K ₃ PO ₄ , K ₂
For materials such as HPO ₄ and KH ₂ PO ₄ that leave non-volatile components as impurities after the firing operation, it is preferable to perform a cleaning operation after the aging operation. The alumina-phosphere aged gel produced by the above-mentioned method is made into a carrier by a generally known method, and then a catalytic metal is supported thereon to serve as a catalyst for various reactions. To briefly explain a known method for forming a carrier, first, the aged gel is given a shape necessary as a carrier by filtration, gel molding, spray drying, or powder molding, and after drying, It is fired at a firing temperature suitable for the purpose of use, stabilized, and if necessary, sized to form a catalyst carrier. The operating conditions for these steps are selected to match the intended use of the catalyst. [Effects of the Invention] As described in detail, the main steps of the method of the present invention are to produce aluminum hydroxide gel in the first step, and then, in the second step, add a phosphorus compound and age it to produce aluminum hydroxide gel. and a phosphorus compound. In this way, by combining aluminum and phosphorus through aging without co-precipitating them, the pore structure can be controlled over a wide range of alumina-phosphere compositions.
As a result, the resulting carriers have a sharp pore distribution and a high mechanical strength. [Application Field of the Invention] The alumina phosphere produced by the method of the present invention can be used as a support for various catalytic reactions. A particularly preferred catalyst carrier is a heavy oil hydrotreating carrier. Heavy oil is composed of large molecules containing many condensed aromatic rings, and contains many catalyst-poisoning substances such as sulfur, nitrogen, vanadium, and nickel. From these points, the properties required of a catalyst carrier for heavy oil hydroprocessing are a sharp pore distribution with large pore diameter and large pore volume, and high mechanical strength. . With the method of the present invention, these heavy oil hydrotreating catalyst supports can be easily produced. Therefore, metals from groups A and 1 of the periodic table or metals from group 2 of the periodic table can be added to the carrier produced by the method of the present invention by a generally known method.
An excellent heavy oil hydrotreating catalyst can be easily produced by supporting the catalyst in an amount of ~30% by weight, followed by drying and calcination. [Example] Hereinafter, the present invention will be explained in more detail with reference to Examples. Example 1 Equipped with a stirrer that can be heated with a steam jacket
40ml of water was placed in a 100 stainless steel reactor and heated to 95°C. Add aluminum nitrate aqueous solution (alumina equivalent concentration 5.4% by weight) to this while stirring.
Then, 2.5 kg of a sodium aluminate aqueous solution (Al/Na=1.6, concentration in terms of alumina 10% by weight) was added. After 5 minutes, add 2 kg of aluminum nitrate aqueous solution, change the pH to acidic, and add 5 kg of aluminum nitrate aqueous solution.
After a few minutes, 2 kg of sodium aluminate aqueous solution was added to change the pH to alkaline. This PH swinging operation was repeated two more times to obtain a precipitate of aluminum hydroxide gel. This precipitate contains Na and
Impurities of NO ₃ were removed by washing to obtain aluminum hydroxide gel (20% by weight as Al ₂ O ₃ ). The aluminum hydroxide gel thus obtained was then filtered to a moldable state, gel molded, air dried at 120°C, and heated to 500°C for 3
After firing for a period of time, a cylindrical extrusion molded product -0 having a diameter of 1 mmφ and a length of about 2 to 5 mm was obtained. Next, 1 kg of the aluminum hydroxide gel was added.
10 with a stirrer that can be heated with an electric heater.
The mixture was placed in an enamel reaction vessel together with water 5, and after stirring for 1 hour to disperse well, the mixture was heated to 90°C. Then, 38 g of 80% by weight phosphoric acid (10% by weight as P ₂ O ₅ based on alumina) was diluted twice with water and added. The pH at this time was 2. The mixture was aged for 1 hour while maintaining the temperature at 90°C. after that,
Filtration, gel forming, air drying at 120℃, 3 at 500℃
After firing for a period of time, a cylindrical extruded product-1 having a diameter of 1 mmφ and a length of about 2 to 5 mm was obtained. A similar operation was carried out to obtain an extruded product-2 from 1 kg of aluminum hydroxide gel and 86 g of phosphoric acid. Further, 1500 g of aluminum hydroxide gel and 403 g of phosphoric acid were added in the same manner, and the same operation was performed except that the pH during aging was adjusted to 7 by adding ammonia water to obtain extruded product-3. Example 2 Approximately 15 kg of aluminum hydroxide gel was obtained in the same manner as in Example 1, except that the PH swing operation of alternately adding aluminum nitrate aqueous solution and sodium aluminate aqueous solution was performed 12 times. 1kg of this
Then, add 5 liters of water to a 10 enamel reaction vessel equipped with a stirrer and reflux condenser that can be heated with an electric heater.
After being well dispersed for 1 hour, it was heated. and 48 g of phosphoric acid (as P ₂ O ₅ for alumina)
10% by weight) was added. The pH at this time was 2. Then, it was aged while boiling, samples were taken after 60 minutes and 24 hours, each was washed, filtered, gel formed, air dried at 120℃, baked at 500℃ for 3 hours, and extruded into a cylindrical shape with a diameter of 1 mmφ. Molded products -1 (60 minutes aging) and -2 (24 hours aging)
I got it. Next, the above aluminum hydroxide gel - 1 kg
and water 5 were placed in a 10 porcelain enamel reaction vessel equipped with a reflux condenser, thoroughly dispersed for 1 hour, and then heated. Next, 108 g of phosphoric acid (calculated as P ₂ O ₅ for alumina)
20% by weight), aged for 2 hours while boiling, air-dried at 120°C, and then fired at 500°C for 3 hours to obtain a cylindrical extrudate-3 with a diameter of 1 mmφ. For comparison, the same procedure as above except that the seed aluminum hydroxide gel was used,
A cylindrical extruded product-0 having a diameter of 1 mmφ was obtained by molding, drying, and baking. Example 3 Water 5 was added to a 10 enamel reaction vessel equipped with a stirrer that could be heated by an electric heater, and 1000 g of the above-mentioned aluminum nitrate aqueous solution was added and heated to 60°C. While stirring, 1100 g of the aforementioned sodium aluminate aqueous solution was added at once to this to form an aluminum hydroxide gel. After 5 minutes, a small amount of the aluminum hydroxide gel precipitate was collected, impurities were washed, filtered, and molded using a small extrusion type gel molding machine. After air drying at 120°C, it was calcined at 500°C for 3 hours.
An extruded product-0 having a diameter of 1 mm was obtained. Next, while keeping the aluminum hydroxide gel precipitate at 60°C, sodium dihydrogen phosphate
74 g of monohydrate was dissolved in 200 c.c. of water and then added.
Aging operation was performed at 60° C. with stirring, and a sample was taken after 1 hour. This sample was treated in the same manner as described above to obtain an extruded product-1 having a diameter of 1 mm. Comparative Example A mixed aqueous solution in which 70 g of phosphoric acid was added to an aqueous aluminum nitrate solution containing 5.4% by weight in terms of alumina, and a sodium aluminate aqueous solution containing 10% by weight in terms of alumina were prepared. Pour 5 of water into a 10 enamel reaction container that can be heated with an electric heater, and bring to 60
heated to ℃. While maintaining the pH in the reaction vessel at 10, the above two aqueous solutions were each added at 20 g/min at 20 g/min.
The mixture was added at a rate of g/min for 1 hour and further aged by stirring for 1 hour to obtain an alumina-phosphere coprecipitated gel. This gel was washed, filtered, gel-molded, air-dried at 120°C, and calcined at 500°C for 3 hours in the same manner as in Example 3 to obtain a 1 mmφ cylindrical extrudate A. The pore distribution and mechanical strength of the cylindrical extrudates obtained in Examples 1 to 3 and Comparative Examples above were measured. The results are summarized in Table 1 and the drawings. The physical properties measurements used in Examples 1 to 3 and Comparative Examples above are as follows. [Pore distribution] The pore distribution and total pore volume of the extruded product were measured using a mercury intrusion porosimeter "Auto Pore9200" manufactured by Micrometritics, USA. [Mechanical strength (SCS)] One grain of the extruded product, dried at 200℃ and left to cool in a desiccator, is placed on a metal pedestal and compressed at a constant speed using air pressure with a diameter of 7mmφ. It is compressed with a piston, the load at breakage is measured, and is defined as the value per 1 mm of length. The values shown in Table 1 are the average values of 50 measurements. [PH] PH was measured using universal PH test paper.

[Table] * Reference example
**Total pore volume application example To 200 g of the -2 extrudate produced in Example 1,
Molybdenum and cobalt were supported as catalyst metal components for hydrogenation in the following manner. That is, ammonium paramolybdate [(NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O]
100 ml of distilled water and 50 ml of 25 weight percent ammonia water were added to 16 g to dissolve it. Separately, 16.9 g of cobalt nitrate [Co(NO ₃ ) _{2.6H 2} O] was dissolved in 50 ml of distilled water. Both solutions were mixed, and distilled water was further added to make the total volume 250 ml. Extrusion molded article-2 was impregnated with the entire amount of this dipping liquid and left sealed overnight. Next, dry at 120℃ using a hot air dryer, and dry at 500℃ using an electric furnace.
The mixture was calcined at ℃ for 3 hours to obtain a heavy oil hydrotreating catalyst. A hydrogenation test was conducted on this catalyst using Arabian baby vacuum residue oil having the properties shown in Table 2 below as a raw material oil. Table-2 Specific gravity (D15/4): 1.0254 Sulfur (wt%): 4.96 Asphaltene (wt%): 11.8 Metal V/Ni (wtppm): 152/47 In this test, a fixed bed flow type small reactor was used. , and the reaction conditions shown in the following table were adopted. Table-3 Reaction temperature (°C): 405 Hydrogen pressure (Kg/cm ² G): 140 Liquid hourly space velocity (hr ^-1 ): 0.3 Hydrogen to oil ratio (Nl/l): 1000 The above hydrotreating test was conducted for 1400 hours. As a result of continued
The asphaluene content in the obtained hydrotreated product is 3.9% at 1000 hours and about 4.2% at 1300 hours, while the vanadium content is 5.1 ppm at 1000 hours,
10ppm in 1300 hours, and the sulfur content is 1000
1.8% in 1300 hours and 2.1 ppm in 1300 hours, confirming that the hydrotreating catalyst using alumina phosphere as a carrier of the present invention has excellent performance.

[Brief explanation of the drawing]

The drawing is a graph showing the relationship between the total pore volume and mechanical strength of the cylindrical extrudates obtained in Examples 1 to 3 and Comparative Example.

Claims (1)

[Claims] 1. A porous alumina characterized by producing an aluminum hydroxide gel from an aluminum compound, then adding a phosphorus compound to the aluminum hydroxide gel under conditions of pH 7 or less, and aging it.・
How to make Bosphia. 2. The method according to claim 1, wherein the addition ratio of the phosphorus compound during ripening is in the range of 0.3 to 30 in terms of Al/P atomic ratio. 3. The method according to claim 1 or 2, wherein the aging conditions are an aging temperature of 50°C to 100°C, an aging time of 5 minutes to 24 hours, and a pH of 7 or less. 4. The method according to claims 1 to 3, wherein after aging, the obtained alumina phosphor gel is washed, filtered, molded and fired to obtain a molded body. 5. The method according to claim 4, wherein the washing operation is performed after the aluminum hydroxide gel is formed.