JPH07196308A - Silica-alumina, its production and catalyst for hydrotreating of light hydrocarbon oil - Google Patents

Abstract

PURPOSE:To obtain a catalyst for hydro treating, having excellent hydrodesulfurization Nactivity against light oil and excellent in uniform dispersibility of supported hydrogenated metal component and a silica-containing alumina as the catalyst support. and to provide a method for producing the silica-containing alumina. CONSTITUTION:This silica-alumina has a structure forming a silica layer on the surface of alumina as a nucleus and the silica-alumina contains 10-20wt.% of silica. The silica-alumina has two peaks of pore volume distribution in the range of a pore diameter of 25-70Angstrom and the first peak exists in the range of a pore diameter of 25-45Angstrom and the second peak exists in the range of a pore diameter of 45-70Angstrom . The ratio of a volume A of pore having diameter in the range of 45-70Angstrom including the second peak to a volume B of a pore having diameter in the range of 0-100 A is 265% and the specific surface area is >=400m<2>/g. A light nyarocarbon oil is hydrotreated using the catalyst having this silica-alumina as a support.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to silica-alumina, a method for producing the same, and a catalyst for hydrotreating light hydrocarbon oils using silica-alumina as a carrier.

[0002]

2. Description of the Related Art Various types of catalysts for hydrotreating hydrocarbon oils have been proposed in the past. Among them, light hydrocarbon oils such as ordinary pressure treated oil and distillate oil under reduced pressure have been proposed. As a catalyst having excellent performance as a hydrorefining catalyst for residual oils and their mixed oils, a hydrogenation-active metal component was supported on an alumina-containing carrier containing silica having a specific pore volume distribution. There is something (Patent Fair 3-3
1496). This known catalyst has a pore diameter of 300.
Pore distribution in both micropores below Å and macropores with pore diameters above that, and excellent performance for both hydrodesulfurization and hydrodenitrogenation reactions. However, according to the studies by the present inventors, in the case of this catalyst, it is still unsatisfactory in terms of the hydrodesulfurization activity of light hydrocarbon oils, and the supported hydrogenation-active metal component is uniformly dispersed on the carrier. It was also found that the dispersibility is still unsatisfactory.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems found in the prior art, has excellent hydrodesulfurization activity for light oil, and has a uniform supported metal hydride component. It is an object of the present invention to provide a hydrotreating catalyst having excellent dispersibility, a silica-containing alumina as a catalyst carrier for the hydrotreating catalyst, and a method for producing the same.

[0004]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, according to the present invention, it has a structure in which a silica layer is formed on the surface of alumina as a core,
Silica-alumina containing 0 to 20% by weight, and having two peaks of pore volume distribution in the pore diameter range of 25 to 70Å, the first peak of which is 25 to 45Å
And the second peak is in the range of 45 to 70 Å
45 to 70 including the second peak.
The volume A of the pores having a diameter in the range of Å is 65% or more of the volume B of the pores having a diameter in the range of 0 to 100Å,
The volume C of the pores having a diameter of 100Å or more is in the range of 0 to 5% of the total pore volume, and the specific surface area is 400.
There is provided a silica-alumina characterized by having m ² / g or more.

Further, according to the present invention, at least one hydrogenation is carried out on a silica-alumina-containing carrier having a structure in which a silica layer is formed on the surface of alumina as a nucleus and containing 10 to 20% by weight of silica. A catalyst supporting an active metal component, which has two peaks of pore volume distribution in a pore diameter range of 25 to 70Å, and the first peak thereof extends in a pore diameter range of 25 to 45Å. The second peaks are present in the pore diameter range of 45 to 70Å, and the volume A of the pores having the diameter in the range of 45 to 70Å including the second peak is 0.
67% of the volume B of pores having a diameter in the range of ~ 100Å
The above is a light hydrocarbon characterized by having a volume C of pores having a diameter of 100 Å or more in the range of 0 to 5% of the total pore volume, and having a specific surface area of 250 m ² / g or more. An oil hydrotreating catalyst is provided.

Furthermore, according to the present invention, the above-mentioned silica-
In the method for producing alumina, an acidic aluminum compound and ammonia are reacted in an aqueous solution to form a precipitate of alumina hydrate, and at that time, the concentration of the alumina hydrate in the aqueous solution is 2.3 in terms of alumina.
A step of producing an aqueous solution containing a precipitate of alumina hydrate by maintaining the pH of the aqueous solution to be not more than 10% by weight and a pH of the aqueous solution in a range of 5.0 to 6.0; Is added to and mixed with an aqueous solution of a water-soluble silicon compound, and the temperature is kept at 60 to 80 ° C. under the condition of pH 7 to 10 to deposit silica hydrate on the alumina hydrate precipitate. A method of making silica-alumina is provided.

In the hydrotreating catalyst of the present invention, a silica-alumina carrier having a structure in which a silica layer is formed on the surface of alumina as a nucleus is used as a catalyst carrier. The content of silica in this catalyst is to control the increase of hydrogen consumption or the production of coke due to the excessive decomposition reaction in the hydrodesulfurization reaction or the hydrodenitrogenation reaction,
It is preferable to set it in the range of 10 to 20% by weight. In addition to silica, this alumina may contain one or more kinds of other refractory inorganic oxides such as magnesia, calcium oxide, zirconia, titania, boria, hafnia and crystalline zeolite. In this case, silica acts to control the solid acidity required for the catalyst,
The specific addition amount is appropriately determined according to the desired catalyst acid strength. Silica imparts a strong acid point (Bronsted acid point) to the catalyst and increases the hydrocarbon decomposition activity of the catalyst, while, for example, magnesia decreases the strong acid point of alumina-silica and the like, and at the same time weak acid point. To increase the selectivity of the catalyst. The magnesia, calcium oxide, zirconia, titania, boria,
The content of refractory inorganic oxides such as hafnia and crystalline zeolite is about 1 to 10% by weight based on alumina-silica.
The range is appropriate. As the alumina, any one of γ-alumina, χ-alumina, η-alumina or a mixture thereof is suitable.

In order to produce silica-alumina suitable as the catalyst carrier of the present invention, first, an acidic aluminum compound and ammonia are reacted in an aqueous solution to form a precipitate of alumina hydrate (alumina hydrogel). As the acidic aluminum compound, aluminum sulfate, chloride, nitrate and the like are used, but the nitrate is preferably used. The reaction temperature is 15 to 80 ° C, preferably 20 to 50 ° C. The reaction pressure is normal pressure. The amount of ammonia used in the reaction is 20 to 40 equivalents, preferably 25 to 40, relative to 1 equivalent of the acidic aluminum compound.
It is a ratio amount of 35 equivalents. In the present invention, when the acidic aluminum compound is reacted with ammonia, the concentration of the alumina hydrate produced in the aqueous solution is changed to alumina (Al
₂ O ₃ ) converted concentration was 1.3 wt%. , Preferably in the range of 1.2 to 1.4% by weight. For this purpose, the concentration of the acidic aluminum compound used in the reaction in the aqueous solution may be adjusted. When the concentration of the produced alumina hydrate in the aqueous solution is higher than the above range, it becomes impossible to obtain silica-alumina rich in micropore structure when silica is deposited on the alumina hydrate.
On the other hand, if the concentration of the produced alumina hydrate in the aqueous solution becomes too low, a practical manufacturing process cannot be obtained.
Further, in the present invention, when the acidic aluminum compound and ammonia are reacted in an aqueous solution, the pH of the aqueous solution is adjusted to 5.0 to 6.0, preferably 5.2 to pH during the reaction operation.
Keep in the range of 5.8. For this purpose, a solution of both the acidic aluminum compound aqueous solution and the ammonia aqueous solution may be simultaneously added to and mixed with the reaction vessel. In this case, the reaction vessel may be prefilled with water in order to adjust the concentration of the alumina hydrate in the aqueous solution. If the pH of the aqueous solution during the reaction operation exceeds the above range, silica-alumina rich in micropore structure cannot be obtained when silica is deposited on alumina hydrate.

In order to preferably carry out the reaction between the acidic aluminum compound and ammonia in the aqueous solution, a reaction vessel previously filled with water is stirred,
Both the acidic aluminum compound aqueous solution and the ammonia aqueous solution are simultaneously added and mixed. The concentration of the aluminum compound in the acidic aluminum compound aqueous solution is not particularly limited, but is usually 1.5 to 3.0% by weight, preferably 2.0 to 2.5% by weight. The ammonia concentration in the aqueous ammonia solution is 3 to 5% by weight, preferably 3.5 to
It is 4.5% by weight. The rate of addition of these aqueous solutions is such that the rate of formation of alumina hydrate in the mixed solution is 0.008 to
0.012 mol / min, preferably 0.007 to 0.01
The rate is preferably 0 mol / min. When the reaction is carried out in this way, the concentration of the produced alumina hydrate in the aqueous solution depends on the amount of water previously filled in the reaction vessel, the amount of the aqueous solution added to the reaction vessel, and the acidic aluminum compound contained in those aqueous solutions. And can be adjusted by varying the amount of ammonia. The aqueous solution containing the precipitate of alumina hydrate obtained as described above is, if necessary, kept at room temperature for about 0.5 to 2 hours, preferably about 1 to 2 hours, and left to stand for aging. By doing so, it can be used as an alumina raw material for producing the silica-alumina of the present invention.

In the present invention, next, an aqueous solution of a water-soluble silicon compound is added and mixed to the aqueous solution containing such a precipitate of alumina hydrate. As the water-soluble silicon compound, alkali metal silicate, tetraalkoxysilane, orthosilicate ester, etc. are used. As the alkali metal silicate, the molar ratio of Na ₂ O: SiO ₂ is 1 :.
Preference is given to using sodium silicate in the range 2 to 1: 4. The concentration of the silicon compound in the aqueous solution is 5 to 10% by weight, preferably 6 to 8% by weight. The amount of the silicon compound added to the aqueous solution containing the alumina hydrate precipitate is an amount corresponding to the composition of the silica-containing alumina as the final product, and the silica content in silica-alumina is 10
-20% by weight. In order to preferably add and mix the aqueous solution of the water-soluble silicon compound to the aqueous solution containing the precipitate of alumina hydrate, the aqueous solution containing the precipitate of alumina hydrate is added at 50 to 90 ° C, preferably 60 to 80 ° C.
At this temperature, the aqueous solution of the water-soluble silicon compound kept at room temperature is added to and mixed with this aqueous solution. The mixed solution of an aqueous solution containing a precipitate of alumina hydrate and an aqueous solution of a water-soluble silicon compound has a pH of 7 to 11, preferably 7 to 11.
The condition of 10 is maintained. In this case, if necessary, a pH adjusting agent such as an aqueous solution of mineral acid or an aqueous solution of sodium hydroxide is added to maintain the pH of the mixed aqueous solution within the above range. This mixed aqueous solution is maintained at a temperature of 60 to 80 ° C, preferably 65 to 75 ° C while stirring. The holding time is 10-35
Minutes, preferably 15-25 minutes. By this operation,
Precipitated particles having silica hydrate deposited on alumina hydrate are obtained. The precipitated particles are separated from the liquid, and then subjected to a conventional washing treatment, for example, a washing treatment using an aqueous solution of ammonium carbonate and water to remove impurity ions, and then a drying and firing treatment. Drying is performed at room temperature to 200 ° C. in the presence or absence of oxygen. Also, firing
200-800 ° C., preferably 550, in the presence of oxygen
Perform at ~ 650 ° C. In this way, it is possible to obtain silica-alumina having a structure in which a silica layer is formed on the surface of an alumina core and having the following specific characteristics.

(1) It has two peaks of pore volume distribution in the pore diameter range of 25 to 70Å. (2) The first peak thereof has a pore diameter in the range of 25 to 45Å. (3) The second peak thereof has a pore diameter in the range of 45 to 70Å. (4) The volume A of the pores having a diameter of 45 to 70Å including the second peak is 60% or more of the volume B of the pores having a pore diameter of 0 to 100Å, particularly in the range of 62 to 75%. It is in. (5) Volume C of pores having a diameter in the range of 100Å or more
Is 0 to 5%. (6) The volume D of pores having a diameter of 25 to 45Å including the first peak is 10 to 25%, preferably 15 to 20% of the volume B of pores having a diameter of 0 to 100Å. (7) 400 m ² / g or more, especially 430 to 450 m ² / g
It has a specific surface area of. (8) 0.4 cc / g or more, especially 0.5 to 0.9 cc /
It has a total pore volume of g.

If necessary, other metal components such as magnesia, calcium oxide, zirconia, boria, hafnia, and crystalline zeolite can be added to the silica-alumina of the present invention. These metal components can be added by a mixing method, or can be added by a conventionally known impregnation method or a coprecipitation method, but it is preferable to add them by an impregnation method. When adding by the impregnation method,
Silica-alumina is immersed in an impregnation solution containing a predetermined soluble metal component to impregnate silica-alumina with a desired amount of the metal component, and then dried and fired.

The hydrotreating catalyst of the present invention can be obtained by supporting a hydrogenation active metal on the silica-alumina. As a method for supporting the hydrogenation active metal, a conventionally known impregnation method or a coprecipitation method can be used, but the impregnation method is preferable. The pore characteristics of the hydrotreating catalyst of the present invention correspond to those of silica-alumina used as a carrier thereof, and the catalyst of the present invention has pore characteristics almost equivalent to those of silica-alumina used as a carrier.

The hydrogenation active metal component supported on silica-alumina in order to obtain a hydrotreating catalyst is one or two selected from the group of metals of Group VIB and Group VIII of the Periodic Table of the Elements. Select the above metals. That is,
Group VIB chromium, molybdenum and tungsten, Group VII
One or more selected from Group I iron, cobalt, nickel, palladium, platinum, osmium, iridium, ruthenium, rhodium, etc. are used. For the hydrodesulfurization of hydrocarbon oils, in particular combinations of Group VIB and Group VIII metals, such as molybdenum-cobalt, molybdenum-nickel, tungsten-nickel, molybdenum-cobalt-nickel or tungsten-cobalt. -A combination such as nickel can be preferably used. It is also possible to add and use a metal of Group VII, for example, manganese, and a metal of Group IV, for example, tin, germanium, etc., to these active metal components. These hydrogenation active metal components are preferably supported as oxides and / or sulfides. In addition, titania or the like can be simultaneously loaded on the carrier in order to enhance the catalyst strength. The supported amount of the metal component is the oxide,
For Group VIII metals, the catalyst may range from about 0.5 to 20% by weight, and Group VIB metals may range from about 5 to 30% by weight. The metal component added for improving the catalyst strength is 0.5 to 1.5% by weight in the catalyst, preferably 0.9.
It is preferable to be in the range of 1.1 wt%.

When the supported metal is supported on silica-alumina by the impregnation method, any one of the one-liquid impregnation method and the two-liquid impregnation method may be adopted depending on the kind of the metal to be supported. That is, in order to support two or more metal components, two or more metal components are mixed and impregnated simultaneously from the mixed solution (one-liquid impregnation method), or two or more metal component solutions are separately prepared. Prepare and sequentially impregnate (two-component impregnation method)
However, the metal supporting method is not particularly limited in the present invention.

In order to preferably produce the catalyst of the present invention, silica-alumina as described above is used as a carrier, and one of the metals selected from the group of metals of Group VIB of the Periodic Table of Elements is first used on this carrier. Support two or more metals
(1st step), then loading one or more metals selected from the group VIII metals of the periodic table of the elements
(Second step). More specifically, according to this two-step method, the hydrogenation active metal component supported on the carrier in the second step is one or more metals selected from Group VIII metals of the periodic table of elements. Is. That is,
Group VIII iron, cobalt, nickel, palladium, platinum,
One or more selected from osmium, iridium, ruthenium and rhodium are used. Preferably, cobalt and nickel are used alone or in combination of both. The hydrogenation active metal component supported on the carrier in the first step is one or more metals selected from the group of Group VIB metals of the Periodic Table of the Elements. That is, one or more selected from the VIB group chromium, molybdenum, and tungsten are used. Preferably molybdenum and tungsten are used alone or in combination.

The hydrogenation-active metal components of Group VIII and Group VIB are preferably supported as oxides and / or sulfides, and in the two-step supporting method according to the first and second steps, the activity is The supported amount of the metal component is 0.1 to 20% by weight, preferably 1 to 8% by weight, and more preferably 2 to 5% by weight in the catalyst, based on the oxide. For Group VIB metals 3 to 30% by weight, preferably 8
-25% by weight, more preferably 5-20% by weight.
If less than 0.1% by weight of the Group VIII metal is supported, a catalyst having sufficient activity cannot be obtained, and if it exceeds 20% by weight, the amount of free metal components not bound to the carrier increases. VI
An increase in the free components of Group II metals results in the formation of inert complex oxides when supporting Group VIB metals,
It lowers the dispersibility of Group VIB metals and lowers the catalytic activity. On the other hand, if the amount of the Group VIB metal is less than 3% by weight, the activity cannot be obtained, and if the amount of the Group VIB metal is more than 10% by weight, the dispersibility is lowered and the cocatalyst effect of the Group VIII metal is not exhibited.

In the method of supporting the catalytic metal, the method of supporting the active metal component on the carrier in the first and second steps is as follows: the carrier is immersed in an aqueous solution of a soluble salt of the metal, and the metal component is introduced into the carrier. An impregnation method can be adopted. As the impregnation operation, the carrier is immersed in the impregnating solution at room temperature or above room temperature to maintain the condition that the desired component is sufficiently impregnated into the carrier. The amount and temperature of the impregnating solution can be appropriately adjusted so that a desired amount of metal is supported. The amount of carrier to be dipped in the impregnation solution is determined according to the supported amount.

The carrier impregnated with the hydrogenation-active metal component is washed with water, dried and calcined after separating the impregnating solution. The conditions of drying and baking may be the same as the conditions for the above carrier. In hydrodesulfurization of heavy hydrocarbon oils, the catalyst is
Prior to use, presulfiding can be performed. The method will be described later. The silica-alumina carrier used in the production of the catalyst of the present invention may have any shape such as a cylindrical shape, a granular shape or a tablet shape. The size of the carrier is not particularly limited, but in the case of the carrier for fixed bed catalyst, the size is usually about 0.5 to 3 mm. Further, the shape and size of the catalyst of the present invention have a shape and size depending on the carrier used.

The catalyst produced as described above is a catalyst in which at least one hydrogenation active metal component is supported on a silica-alumina carrier containing about 10 to 20% by weight of silica. It is characterized by having pore characteristics. (1) It has two peaks of pore volume distribution in the pore diameter range of 25 to 70Å. (2) The first peak thereof has a pore diameter in the range of 25 to 45Å. (3) The second peak is in the range of 45 to 70Å. (4) The volume A of pores having a diameter of 45 to 70Å including the second peak is 67% or more, particularly 69 to 75% of the volume B of pores having a diameter of 0 to 100Å. It is in. (5) Volume C of pores having a diameter in the range of 100Å or more
Is 2 to 4% of the total pore volume. (6) The volume D of the pores having the diameter of 25 to 45Å including the first peak is 18 to 25% of the volume B of the pores having the diameter of 0 to 100Å. (7) 240 m ² / g or more, particularly 250 to 260 m ² / g
It has a specific surface area of. (8) 0.35 cc / g or more, particularly 0.37 to 0.5 c
It has a total pore volume of c / g.

The pore volumes of the silica-alumina and the catalyst in the present specification are those measured by the nitrogen adsorption method. H. Emmet et al., "Catalysis," Vol. 1, p. 123 (Published by Reinhold Publishing Company) (1959) PH E
mmett, et al. “Catalysis”, 1,123 (1959) (ReinholdPub
lishing Co.) and Catalysis Engineering Course, Volume 4, Page 69-
It is described on page 78 (published by Jishin Shokan) (1964). Various correction methods based on multi-layer adsorption have been proposed for the nitrogen adsorption method, and among them, the BJH method [E.
P. Barreff. LG Joyner and PPHalnda, J._Amer.,
Chem, Sco., 73 , 373 (1951)] and CI method [RW Cranst
on and FA Inkley, “Advances in Catalysis,” 1X , 1
43 (1957) (New York Academic Press)] is commonly used. The data relating to the pore volume in the present invention is BJ.
It is calculated by the H method.

Next, hydrorefining of a light hydrocarbon oil by using the catalyst of the present invention will be described. As the light hydrocarbon oil, straight-run light oil, catalytically cracked light oil, thermally cracked light oil, vacuum distilled light oil, heavy cracked oil and the like can be used. Vacuum-distilled gas oil is obtained by distilling residual oil under atmospheric pressure under reduced pressure.
It is a distillate oil containing a fraction having a boiling point in the range of 70 ° C to 610 ° C, and contains a considerable amount of a sulfur content, a nitrogen content and a metal content. For example, to give an example of Middle East crude oil vacuum distillation gas oil, sulfur content of about 2-4% by weight, about 0.05
Contains 0.2% by weight of nitrogen. Heavy cracked oil is a cracked oil having a boiling point of about 200 ° C. or higher, which is obtained by thermally cracking residual oil, and is obtained, for example, from light cycle oil from a catalytic cracker, coking of residual oil and visbreaking. Diesel oil can be used.

The reaction conditions can be appropriately selected according to the type of feed oil, the desired desulfurization rate or denitrification rate. That is, reaction temperature: about 320 to 420 ° C., reaction pressure: about 30 to 200 kg / cm ² , ratio of hydrogen-containing gas to feedstock oil: about 100 to 270 liters / liter, and liquid space velocity: about 0.2 to 2 Adopt 0.0V / H / V. The hydrogen concentration in the hydrogen containing gas may range from about 60-100%. In carrying out the hydrodesulfurization, the catalyst may be used in any form of a fixed bed, a fluidized bed or a moving bed, but it is preferable to adopt the fixed bed in terms of equipment or operation. It is also possible to combine two or more reaction towers for hydrodesulfurization to achieve a high desulfurization rate.

The catalyst of the present invention may optionally be presulfidized prior to use. Presulfiding can be carried out in situ in the reaction tower. That is, the calcined catalyst was mixed with sulfur-containing distillate oil, temperature: about 150 to 400 ° C., pressure (total pressure): about 15 to 100 kg / cm ² , liquid hourly space velocity;
It is contacted in the presence of about 0.3 to 2.0 V / H / V and about 50 to 1500 liters of a hydrogen-containing gas, and after completion of the sulfurization treatment, the sulfur-containing distillate oil is changed to a feedstock oil and is suitable for desulfurization of the feedstock oil. Set the proper operating conditions and start the operation. In addition to the above methods, the sulfurization treatment may be carried out by directly contacting the catalyst with hydrogen sulfide or other sulfur compound, or by adding it to a suitable distillate oil and contacting it with the catalyst.

[0025]

The catalyst of the present invention has the following catalytic properties.
The catalyst of the present invention is characterized in that the pore diameter is 1 or more.
There is a first peak of pore volume distribution in the range of 0 to 25Å and a second peak of pore volume in the range of pore diameter of 25 to 50Å, and the second peak is larger than the first peak, and That is, there is almost no volume of pores having a diameter of 100 Å or more. The catalyst of the present invention has the following advantages in catalytic performance as compared with the known catalyst having a macropore structure (Japanese Patent Publication No. 3-31496). (1) Uniform dispersibility of the supported hydrogenation active metal is high.
The reason for this is that the silica-alumina used as a carrier in the present invention has a large specific surface area and is excellent in metal-supporting property. (2) Compared to a carrier containing only alumina, the amount of acid is large and the acid strength is high, so that it has a hydrocracking function, and has a structure that causes steric hindrance to the hydrogenation reaction, and is difficult to desulfurize and contain sulfur. The compounds can also be easily desulfurized. The silica-alumina of the present invention has a structure in which alumina is a nucleus and silica is layered on the surface thereof, and has pore characteristics equivalent to those of the catalyst described above. This product is suitably used as a carrier for hydrodesulfurization catalyst, and is also used as a catalyst carrier, an adsorbent, a filler, and the like, like conventional silica-alumina.

[0026]

EXAMPLES Next, examples of the present invention will be described. Example 1 aluminum nitrate _{(Al (No 3) 3 ·} 9H 2 O) 368
g was dissolved in 2 liters of pure water to prepare a 2 wt% aluminum nitrate aqueous solution (pH: 0.3) in terms of Al ₂ O ₃ conversion concentration. Separately from this, pure water was added to 300 ml of ammonia water (ammonia concentration: 28 wt%) to prepare 2 liters of ammonia water (LN-ammonia water). Next, 2 liters of the aqueous solution of aluminum nitrate obtained as described above was added dropwise to 1.5 liters of ammonia water in a reaction vessel containing 1 liter of pure water with stirring in a conventional manner.
A precipitate of hydrated alumina was formed. In this case, the dropping of these two solutions started at the same time and ended at the same time. The dropping time was about 70 minutes. In the dropwise addition of these solutions, the fluctuation of the pH of the mixed solution was kept at about 5.5 during the dropping operation. The concentration of alumina hydrate in the solution was 1.1 wt% in terms of alumina. This aqueous solution was aged by allowing it to stand at room temperature for 1 hour.

Next, 3.5 liters of the slurry solution containing the precipitate of alumina hydrate thus obtained was heated from room temperature to 70 ° C. for 20 minutes under stirring, and this solution was added to
While stirring, water glass No. 3 (SiO ₂ content: 29 wt
%) 43 g dissolved in pure water 130 ml (SiO ₂
Immediately after adding (content: 7 wt%) 1N-NaO
About 200 ml of H aqueous solution was added, and the pH of the slurry solution was adjusted to 7
Adjusted to. The slurry solution was aged for 10 minutes while stirring. As a result, a slurry liquid containing precipitated particles in which silica hydrate was deposited on the surface of alumina hydrate was obtained. A slurry solution containing precipitated particles in which silica hydrate was deposited on the surface of alumina hydrate was obtained. The slurry solution was filtered, and the filtered cake was washed with an aqueous ammonium carbonate solution until the sodium concentration of the filtrate after filtration was 5 ppm or less. This cake was kneaded while being dried in a kneader at 80 ° C. until it had a water content capable of being molded, and was molded into a cylindrical pellet of 1.5 mmφ by an extrusion molding machine. The formed pellets were dried at 120 ° C. for 16 hours and further calcined in air at 500 ° C. for about 4 hours to obtain a carrier. Then, about 20 as an oxide is added to this carrier.
An aqueous solution of ammonium paramolybdate (molybdenum solution) was impregnated so that molybdenum of wt% was supported, dried, and baked at 550 ° C. Next, an aqueous solution of cobalt nitrate (cobalt solution) is impregnated so that about 5 wt% of cobalt is supported as an oxide, and dried at 450 ° C.
It was then calcined to obtain a catalyst.

Example 2 The pelletized carrier obtained in Example 1 was impregnated with an ammonium paramolybdate aqueous solution (molybdenum solution) so that about 17 wt% of molybdenum was supported as an oxide, and dried. It was baked at 550 ° C. Next, a cobalt solution was impregnated so that about 4.6 wt% of cobalt was supported as an oxide, dried, and calcined at a temperature of 450 ° C. to obtain a catalyst.

The properties of each of the catalysts obtained as described above are shown in Table 1 together with the comparative catalyst. The symbols shown in Table 1 indicate the following contents. A: Pore volume with a pore diameter of 45 to 70Å B: Pore volume with a pore diameter of 0 to 100Å C: Pore volume with a pore diameter of 100Å or more D: Fine Pore volume with pore diameter in the range of 25 to 45Å E: Total pore volume Further, Comparative Catalyst A shown in Table 1 is a commercially available desulfurization catalyst, and Comparative Catalyst B is disclosed in Japanese Examined Patent Publication No. 3-31496. The catalyst obtained according to the description.

[0030]

[Table 1]

Application Example 1 Using the catalyst of Example 1 and the comparative catalysts A and B, the hydrodesulfurization treatment of the cracked gas oil fraction obtained from the catalytic cracking apparatus was carried out. Table 2 shows the hydrodesulfurization conditions.

[0032]

[Table 2] Table 3 shows the results of the hydrodesulfurization treatment. The sulfur level of the hydrotreated product oil is 0.04 to 0.08 wt%.

[0033]

[Table 3]

Application Example 2 Using Example 1 and Comparative Catalysts A and B, a hydrodesulfurization treatment of a straight-run light oil fraction was carried out. The sulfur level of the hydrotreated product is 0.01 to 0.05 wt%. Table 4 shows the hydrodesulfurization conditions.

[0035]

[Table 4] Table 5 shows the results of the hydrodesulfurization treatment. The sulfur level of the hydrotreated product oil is 0.04 to 0.07 wt%.

[0036]

[Table 5]

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C10G 45/08 2115-4H

Claims (3)

[Claims] 1. A silica-alumina having a structure in which a silica layer is formed on the surface of alumina as a core and containing 10 to 20% by weight of silica, and having a pore diameter of 25 to 70.
There are two peaks of pore volume distribution in the range of Å, the first peak exists in the range of pore diameter 25 to 45Å and the second peak exists in the range of pore diameter 45 to 70Å, respectively. , The volume A of pores having a diameter in the range of 45 to 70Å including the second peak is 60% or more of the volume B of pores having a diameter in the range of 0 to 100Å, and has a diameter of 100Å or more. Silica-alumina having a pore volume C in the range of 0 to 5% of the total pore volume and a specific surface area of 400 m ² / g or more. 2. A silica-alumina-containing carrier having a structure in which a silica layer is formed on the surface of alumina as a core and containing 10 to 20% by weight of silica, and at least one hydrogenation-active metal component is supported on the carrier. The catalyst has two peaks of the pore volume distribution in the pore diameter range of 25 to 70Å, the first peak of which is in the pore diameter range of 25 to 45Å and the second peak thereof. The volume A of the pores each having a diameter of 45 to 70 Å and having a diameter of 45 to 70 Å including the second peak is 67% of the volume B of the pores having a diameter of 0 to 100 Å. And above, and 10
The volume C of pores having a diameter of 0Å or more is 0 of the total pore volume.
In the range of up to 5% with a specific surface area of 250 m ² / g
The above is a catalyst for hydrotreating light hydrocarbon oil. 3. The method for producing silica-alumina according to claim 1, wherein the acidic aluminum compound and ammonia are reacted in an aqueous solution to form a precipitate of alumina hydrate, and at that time, the alumina hydrate A step of producing an aqueous solution containing a precipitate of alumina hydrate by keeping the concentration in the aqueous solution in terms of alumina at 2.5% by weight or less and keeping the pH of the aqueous solution in the range of 4.5 to 6.5. And an aqueous solution of a water-soluble silicon compound are added to and mixed with an aqueous solution containing a precipitate of this alumina hydrate, and
A method for producing silica-alumina, comprising the step of depositing silica hydrate on an alumina hydrate precipitate while maintaining the temperature at 60 to 80 ° C. under the condition of 10.