JPH09929A - Catalyst for hydrodesulfurization of light oil - Google Patents

Abstract

PURPOSE: To obtain the subject catalyst capable of effectively removing even sulfur compds. hard to remove in a deep desulfurization region. CONSTITUTION: Cobalt and/or nickel and molybdenum are carried on an inorg. oxide carrier by 1-10wt.% (expressed in terms of oxides) and 10-25wt.% (expressed in terms of oxide) respectively based on the amt. of the resultant catalyst and tungsten is further carried by such an amt. as to regulate the weight ratio of tungsten to molybdenum to 0.01-0.2 (expressed in terms of oxides). The average pore diameter of the resultant catalyst is 60-90Å.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas oil hydrodesulfurization catalyst capable of effectively removing even sulfur compounds which are considered to be difficult to desulfurize in a deep desulfurization region.

[0002]

Hydrocarbon oils generally contain sulfur compounds,
When these oils are used as fuels, the sulfur present in the sulfur compounds is converted to sulfur compounds and discharged into the atmosphere. Therefore, it is desirable that the sulfur content in the hydrocarbon oil be as low as possible in consideration of the pollution of the air when it burns. Reduction of sulfur content can be achieved by catalytic hydrodesulfurization of hydrocarbon oils.

Further, due to environmental problems, regulations on sulfur content in commercial gas oil are becoming more stringent (0.2 w of conventional products).
t% to 0.05 wt%), further deep desulfurization is required, and 4-MDBT (4 methyldibenzothiophene) and 4,6- It is necessary to treat a hardly desulfurizable substance centered on DMDBT (4,6 dimethyldibenzothiophene).

The catalyst used for hydrodesulfurization intended for such deep desulfurization is a group VI (hereinafter,
A catalyst in which a metal (referred to as “Group 6”) and a metal of Group VIII (hereinafter referred to as “Group 8”) of the periodic table are used as active metals and which is supported on an oxide carrier such as alumina, magnesia, or silica. Generally, Mo is used as the Group 6 metal, and Co or Ni is used as the Group 8 metal.
Further, in order to improve the activity of this catalyst, addition of phosphorus, boron and the like has been reported (JP-A-52-13503).

A technique for incorporating tungsten into a combined catalyst of Groups 6 and 8 for hydrodesulfurization of hydrocarbon oil has been reported (Applied Catal).
ysis A: General 109 (1994) 1
95-210), this technique is mainly intended for deasphaltening heavy oil, but not for deep desulfurization of light oil and desulfurization of hardly desulfurizable substances.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a gas oil hydrodesulfurization catalyst having excellent desulfurization activity in the deep desulfurization region.

[0007]

As a result of repeated studies to achieve the above object, the present inventors have noticed that (1) tungsten exerts an effect on the hydrogenation of refractory sulfur compounds. When a specific ratio of tungsten was supported on molybdenum on a cobalt-molybdenum catalyst or a nickel-molybdenum catalyst, which is a conventional hydrodesulfurization catalyst of a combined group 6-8 group, The one having a pore size can effectively remove the hardly desulfurizable sulfur compound in the deep desulfurization region, and (2) this hydrodesulfurization is conducted with the hardly desulfurizable substances such as 4-MDBT and 4,6-DMDBT. The present inventors have completed the present invention by obtaining the knowledge that hydrogen is effectively removed by partial nuclear hydrogenation.

That is, according to the present invention, 1 to 10% by weight of cobalt and / or nickel on a catalyst basis and 10 to 25% by weight of molybdenum on an inorganic oxide carrier are calculated on the basis of a catalyst. %, And the weight ratio of tungsten and molybdenum is 0.01 to 0.
A gas oil hydrodesulfurization catalyst is characterized in that tungsten is supported so as to be 2 and the average pore diameter of the catalyst is 60 to 90Å.

The carrier of the catalyst of the present invention is a crystalline inorganic oxide. As this inorganic oxide, various ones can be used, for example, silica, alumina, boria, magnesia,
Titania, silica-alumina, silica-magnesia, silica-zirconia, silica-tria, silica-beryllia, silica-titania, silica-boria, alumina-zirconia, alumina-titania, alumina-boria, alumina-chromia, titania-zirconia, Silica-alumina-thorium, silica-alumina-zirconia, silica-alumina-magnesia, silica-magnesia-zirconia, etc. These can be used alone or in combination of two or more kinds.

Of these inorganic oxides, preferred are alumina, silica-alumina, alumina-titania, alumina-boria, and alumina-zirconia, and γ-alumina is particularly preferred.

The above carrier (or the catalyst of the present invention comprising the above carrier) includes montmorillonite, kaolin,
One or more kinds of clay minerals such as halosite, bentonite, adabargite, bauxite, kaolinite, nacrite and anoxite may be contained.

The specific surface area of the carrier composed of these inorganic oxides is not particularly limited, but is 250 m ² / g.
The above is preferable. The pore volume of the carrier is not particularly limited, but is preferably 0.4 to 1.2 cc / g. The average pore size of the carrier is also not particularly limited, but in order to set the average pore size of the catalyst of the present invention to 60 to 90Å,
It is preferable to use the one having 0 to 130Å.

The catalyst of the present invention is such that cobalt and / or nickel, molybdenum, and tungsten are supported on the above carrier in specific amounts.

The amount of cobalt and / or nickel supported is 1 to 1 in terms of oxide, based on the catalyst.
It is 10% by weight, preferably 3 to 7% by weight. 1% by weight of cobalt and / or nickel
If it is less than 10% by weight, the hydrodesulfurization activity is not expressed.
Even if it is more, the corresponding improvement in the activity cannot be obtained,
It is economically disadvantageous.

The amount of molybdenum supported is 10 to 25% by weight, preferably 15 to 20% by weight. If the amount of molybdenum is less than 10% by weight, the absolute amount of molybdenum that acts as an active site becomes too small, and hydrodesulfurization activity does not appear. If it is more than 25% by weight, agglomeration of metallic molybdenum occurs, and conversely the active site And the hydrodesulfurization activity is reduced.

The amount of tungsten supported is such that the weight ratio of tungsten to molybdenum is WO ₃ : MoO ₃ =
0.01: 1 to 0.20: 1, preferably 0.02: 1
~ 0.1: 1, more preferably 0.04: 1 to 0.0
The amount should be 7: 1. When the WO ₃ : MoO ₃ weight ratio (hereinafter simply referred to as “ratio”) is less than 0.01,
If the nuclear hydrogenation activity of the above-mentioned difficult-to-desulfurize substances is not expressed and the weight ratio of molybdenum to tungsten is more than 0.2, the amount of tungsten to be supported is too large, and the metallic tungsten is the same as in the case of molybdenum. Agglomeration occurs, the number of active sites decreases, and the removal efficiency of the hardly desulfurizable substance in hydrodesulfurization decreases.

There is no particular limitation on the method or order of loading these cobalt and / or nickel, molybdenum and tungsten on the above inorganic oxide support. For example, (1) first impregnating and supporting a molybdenum salt solution, then impregnating and supporting a salt solution of cobalt and / or nickel, and then impregnating and supporting a tungsten salt solution, or (2) first of a molybdenum salt solution. Impregnation support, then impregnation support with a tungsten salt solution, and then impregnation support with a salt solution of cobalt and / or nickel,
(3) First, impregnating and supporting a tungsten salt solution, then impregnating and supporting a molybdenum salt solution, and then impregnating and supporting a salt solution of cobalt and / or nickel, or (4) first, a molybdenum salt solution and a tungsten salt. The solution and the salt solution of cobalt and / or nickel may be simultaneously impregnated and supported.

After the impregnation, the catalyst of the present invention is obtained by drying and calcining. At this time, the impregnation of each of the above-mentioned solutions is divided into a plurality of times so that each of the active ingredients is supported so as to have the above-mentioned supported amount. In the above, a drying and firing step may be provided between each impregnation step.

When each active ingredient is supported by the above-mentioned impregnation method, various salts of cobalt or nickel can be used, and examples thereof include carbonates, acetates, nitrates, lead sulfates and phosphates. Yes, these salts are
Each can be used alone or in combination of two or more.

Various salts of molybdenum can be used, for example, ammonium molybdate ((NH ₄ )).
_{6 Mo 7 O 24 · 4H 2} O), molybdophosphoric acid (H
₃ (PMo ₁₂ O ₄₀ ) .30H ₂ O), molybdenum oxide (MoO ₃ ), and the like. These salts can be used alone or in combination of two or more kinds.

Various salts of tungsten can be used. For example, ammonium paratungstate (5
_{(NH 4) 2 O · 12WO} 3 · 11H 2 O), ammonium metatungstate _{((NH 4) 2 W 4} O 13 · 8
H ₂ O), tungstic acid (H ₂ WO ₄ ), tungstophosphoric acid (H ₃ (PW ₁₂ O ₄₀ ) .30H ₂ O) and the like, and these salts may be used alone or in the form of 2
More than one species can be used in combination.

Molybdenum salt, tungsten salt,
The solvent for dissolving the cobalt or nickel salt is not particularly limited, and various solvents can be used, and examples thereof include water, alcohols, ethers, ketones, and aromatics. Preferably,
Water, acetone, methanol, n-propanol, i-propanol, n-butanol, i-butanol, hexanol, benzene, toluene, xylene, diethyl ether, tetrahydrofuran, dioxane and the like are preferable, and water is particularly preferable.

The mixing ratio of each active ingredient constituting each solution of molybdenum salt, tungsten salt, cobalt or nickel salt (that is, the concentration of each solution) is not particularly limited, but impregnation operation and drying are performed. Considering the ease of the calcination operation, the amount of the solvent in each of these impregnation operations is 50 to 150 g, preferably 70 to 90 g, relative to 100 g of the carrier (impregnation is divided into a plurality of times, and each impregnation step In the case of providing a dry baking step in, the amount of the solvent in each impregnation step and each dry baking step is suitable as this amount). The ratio may be the above-mentioned amount converted to oxide with respect to the calcined catalyst.

The impregnation conditions for impregnating each of the above solutions are not particularly limited, but usually the temperature is 10 to 100.
℃, preferably 10 to 50 ℃, more preferably 15 ~
A temperature of 30 ° C is suitable. At this time, it is preferable to carry out stirring. The time (time of each impregnation step when the impregnation is divided into a plurality of times) is usually 15 minutes to 3 hours,
Preferably 20 minutes to 2 hours, more preferably 30 minutes to
1 hour is suitable.

The catalyst of the present invention is impregnated with each of the above-mentioned solutions under the above-mentioned conditions (when impregnation is divided into a plurality of times and a drying and calcination step is provided between the impregnation steps, a total impregnation step and a total dry and calcination step). By carrying out the carrier carrying each active ingredient,
It is manufactured by further drying and firing.

Drying at this time (including each drying when the impregnation is divided into a plurality of times and a drying and firing step is provided between each impregnation step) is performed by various drying methods such as air drying, hot air drying, heat drying and freeze drying. It can be performed by a method.

The temperature during firing (including each firing when the impregnation is divided into a plurality of times and a drying firing step is provided between each impregnation step) is 400 to 500 ° C., preferably 450 to 500.
C is suitable, and the time (time for each firing step when impregnation is divided into a plurality of times and a drying and firing step is provided between each impregnation step) is 2 to 10 hours, preferably 3 to 5 hours. ing.

In the catalyst of the present invention prepared as described above, the specific surface area and the pore volume are not particularly limited as long as it can function as a catalyst, but the hardly desulfurizable substance is effectively removed. To achieve this, the specific surface area is 2
00 m ³ / g or more, pore volume is 0.4 to 1.2 cc / g
Is preferred.

The average pore diameter is 60 to 90Å, preferably 70 to 80Å. When the average pore size is less than 60Å, the reactants are less likely to diffuse into the pores, and therefore the nuclear hydrogenation reaction of the hardly desulfurizable substance does not occur effectively, and the physical properties required to function as a catalyst ( Attempting to obtain (specific surface area, pore volume) causes problems in manufacturing, such as insufficient mechanical strength.

If it is larger than 90Å, the diffusibility of the reaction substance into the pores is good, but the effective surface area of the catalyst is small, so that it is also difficult to remove the hardly desulfurizable substance. More specifically, when performing a deep desulfurization reaction, it is important to reduce the sulfur content to below a predetermined level without deteriorating the hue of the produced gas oil. Many. In this case, since the contact time becomes long, it is not necessary to use a catalyst having an average pore size larger than 90Å to improve the diffusivity of the reactants, and conversely, to use a catalyst having an average pore size larger than 90Å. When it is used, the contact effect between the reaction substance diffused in the pores and the reaction surface is reduced, and the improvement in activity cannot be observed.

The pore size distribution of the catalyst (that is, the proportion of pores having an average pore size of ± 15Å) is 70
% Or more, preferably 80% or more is suitable. If the value of the pore size distribution is small and the distribution curve is broad, the number of effective pores for the reaction will be relatively small even if the average pore size is ideal, and a highly active catalyst will be obtained. Can not be expected.

The shape of the catalyst of the present invention is not particularly limited, and various shapes used for ordinary catalyst shapes can be used, and for example, a four-lobed shape or a cylindrical shape can be used. The size of the catalyst of the present invention is usually 1 /
10 to 1/22 inch is suitable.

The catalyst of the present invention may be used as a mixture with a known catalyst or a known inorganic oxide carrier.

The feed oil which can be hydrodesulfurized by using the catalyst of the present invention includes straight-run light oil obtained by atmospheric distillation of crude oil,
Alternatively, cracked gas oil produced from a catalytic cracker, vacuum gas oil obtained by vacuum distillation, and the like can be mentioned.
Boiling point is 150 to 600 ° C, preferably 200 to 400
℃, sulfur content is less than 3 wt%, preferably 2.5 wt%
Hereinafter, those having a density (15 ° C.) of 0.94 g / cm ³ or less are preferable.

When the catalyst of the present invention is used in a desulfurization apparatus by catalytic hydrotreating on a commercial scale, it is used as a fixed bed, a moving bed or a fluidized bed, and the gas oil to be desulfurized is introduced therein to obtain a high temperature. , Under high pressure (equivalent hydrogen partial pressure),
Perform the desired desulfurization. Most commonly, the catalyst is maintained as a fixed bed, with light oil passing downward through the fixed bed. The catalyst can be used in a single reactor or even in several reactors in series. In particular, when the feedstock oil is a relatively heavy gas oil, it is preferable to use a multistage reactor.

As a preferable example of the reaction, a light oil is used at a temperature of about 200 to 500 ° C., more preferably about 250 to 40.
At 0 ° C., the liquid hourly space velocity is about 0.05 to 5.0 hr ⁻¹ , more preferably about 0.1 to 4.0 hr ⁻¹ , and the hydrogen partial pressure is about 10 to 200 kg / cm ² G, more preferably. About 30
In ~100kg / cm ² G, it is contacted with the catalyst.

[0037]

[Examples] The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example 1 Ammonium molybdate 32.7 in an Erlenmeyer flask.
g was dissolved in 75 g of water, ammonia water was further added until ammonium molybdate was completely dissolved, and the mixture was stirred to prepare an aqueous solution of ammonium molybdate.

In a separate Erlenmeyer flask, cobalt nitrate 26
g was dissolved in 75 g of water and stirred to prepare an aqueous solution of cobalt nitrate.

In a further Erlenmeyer flask, the WO ₃ / MoO ₃ ratio in the catalyst of the final product of this example is 0.05.
Ammonium metatungstate 2.6
g was dissolved in 75 g of water and stirred to prepare an aqueous solution of ammonium metatungstate.

In an eggplant-shaped flask, 100 g of a γ-alumina carrier having a specific surface area of 336 m ² / g, a pore volume of 0.71 cc / g and an average pore diameter of 85Å was impregnated with the above ammonium molybdate aqueous solution. The impregnation temperature is normal temperature,
The impregnation time was 1 hour. Then, it was dried (air-dried) and baked in a muffle furnace at 500 ° C. for 4 hours to complete the first stage impregnation and loading (impregnation and loading of molybdenum salt solution).

The catalyst after the completion of the impregnation on the first stage was impregnated with an aqueous solution of cobalt nitrate in an eggplant-shaped flask under the same conditions as in the impregnation operation of the first stage, and under the same conditions as the dry firing of the first stage. After that, the mixture was dried and calcined to complete the second stage impregnation and loading (cobalt salt solution impregnation and loading).

The catalyst after completion of the impregnation in the second step was impregnated with an aqueous solution of ammonium metatungstate in an eggplant-shaped flask under the same conditions as in the impregnation operation in the first step, and dried in the same manner as in the first step. The catalyst A was prepared by drying and firing under the conditions to complete the third stage impregnation and loading (impregnation and loading of the tungsten salt solution).

Example 2 A catalyst B was prepared in the same manner as in Example 1 except that 26 g of nickel nitrate was used instead of 26 g of cobalt nitrate which was impregnated and supported in the second stage.

Example 3 Ammonium molybdate 32.7 with impregnation on the first stage 32.7
16.3 g was used instead of g, and 0.236 g of tungstic acid was used so that the WO ₃ / MoO ₃ ratio was 0.02 instead of the cobalt nitrate of the second stage impregnated and supported, and this was completely dissolved. Using an aqueous solution with ammonia water added,
A catalyst C was prepared in the same manner as in Example 1 except that 26 g of cobalt nitrate was used instead of ammonium metatungstate for impregnation on the third stage.

Example 4 6.47 g of tungstophosphoric acid was used in place of ammonium molybdate supported on the first stage, and WO ₃ / MoO ₃ ratio was 0.02 in place of cobalt nitrate supported on the second stage.
Catalyst A was prepared in the same manner as in Example 1 except that 40.9 g of ammonium molybdate was used and 26 g of cobalt nitrate was used in place of the metatungstic acid impregnated and supported in the third stage.

Example 5 In an Erlenmeyer flask, 32.7 g of ammonium molybdate and 0.97 g of ammonium paratungstate were dissolved in 75 g of water so that the WO ₃ / MoO ₃ ratio was 0.03. Ammonium water was added until ammonium and ammonium paratungstate were completely dissolved and stirred to prepare a mixed aqueous solution of ammonium paratungstate and ammonium molybdate.

In another Erlenmeyer flask, cobalt nitrate 26
g was dissolved in 75 g of water and stirred to prepare an aqueous solution of cobalt nitrate.

In a eggplant-shaped flask, 100 g of the same γ-alumina carrier as the carrier used in Example 1 was impregnated with the mixed aqueous solution of ammonium paratungstate and ammonium molybdate under the same conditions as in Example 1. It was dried and calcined to carry out impregnation and loading in the first step (impregnation and loading of tungsten salt and molybdenum salt).

The catalyst after the completion of the impregnation in the first step was impregnated with the above aqueous solution of cobalt nitrate in an eggplant-shaped flask under the same conditions as in the impregnation operation in the first step, and the same as in the dry firing in the first step. The catalyst E was prepared by drying and calcining under the conditions described above to complete the second stage impregnation and loading (impregnation and loading of the cobalt salt solution).

Example 6 Example 6 was carried out except that ammonium metatungstate 3.8 g was used so that the WO ₃ / MoO ₃ ratio was 0.07 instead of the first stage impregnated and supported ammonium paratungstate 0.97 g. Catalyst F was prepared in the same manner as in Example 5.

Example 7 Ammonium molybdate 32.7 on the first stage impregnated and supported
g was replaced by 24.5 g, and the WO ₃ / MoO ₃ ratio was 0.07.
Catalyst G was prepared in the same manner as in Example 1 except that

Example 8 Except that 13 g of cobalt nitrate and 13 g of nickel nitrate were used in place of 26 g of cobalt nitrate for impregnation on the second stage,
Catalyst H was prepared in the same manner as in Example 1.

Example 9 Specific surface area of 358 m ² / g, pore volume of 0.54 cc /
A catalyst I was prepared in the same manner as in Example 1 except that a γ-alumina carrier having an average pore size of 53Å was used.

Example 10 Specific surface area 241 m ² / g, pore volume 0.75 cc /
A catalyst J was prepared in the same manner as in Example 1 except that a γ-alumina carrier having an average pore size of 92Å was used.

Comparative Example 1 A catalyst K was prepared in the same manner as in Example 1 except that the third stage impregnation and loading was not carried out.

Comparative Example 2 Ammonium molybdate 32.7 impregnated and supported in the second stage
13.3 g was used instead of g, and WO ₃ / was used instead of 2.6 g of ammonium metatungstate for impregnating and supporting in the third stage.
A catalyst L was prepared in the same manner as in Example 1 except that 0.92 g was used so that the MoO ₃ ratio was 0.05.

Comparative Example 3 Ammonium molybdate 32.7 impregnated and supported in the second stage
In place of g, 49.1 g was used, and in place of 2.6 g of ammonium metatungstate for impregnating and supporting in the third stage, WO ₃ /
A catalyst M was prepared in the same manner as in Example 1 except that 4.7 g was used so that the MoO ₃ ratio was 0.05.

Comparative Example 4 Same as Example 1 except that 0.27 g of WO ₃ / MoO ₃ ratio of 0.005 was used in place of 2.6 g of ammonium metatungstate supported on the third stage. Catalyst N was prepared by the method described in 1.

Comparative Example 5 The same as Example 1 except that 2.6 g of ammonium metatungstate supported on the third stage was replaced with 14.0 g so that the WO ₃ MoO ₃ ratio was 0.25. Method to prepare catalyst O.

Comparative Example 6 Specific surface area of 190 m ² / g, pore volume of 0.71 cc /
A catalyst P was prepared in the same manner as in Example 1 except that a γ-alumina carrier having an average pore size of 101Å was used.

The compositions of the catalysts A to P prepared in Examples 1 to 8 and Comparative Examples 1 to 6 are shown in Table 1, and their properties are shown in Table 2.

[0063]

[Table 1]

[0064]

[Table 2]

Using the catalysts A to P prepared in the above Examples 1 to 8 and Comparative Examples 1 to 6, hydrodesulfurization reaction of light oil was carried out under the reaction conditions shown in Table 2.

[0066]

[Table 3]

The catalyst performance was evaluated by operating under the above reaction conditions, measuring the sulfur content after passing oil for 100 hours, determining the reaction rate constant based on the following formula, and setting the value of catalyst K to 10
The relative evaluation was set to 0. The results are shown in Table 4.

[0068]

[Equation 1]

[0069]

[Table 4]

Further, the above Examples 1 to 8 and Comparative Example 1
The produced oil obtained by using the catalysts A to P prepared in 6 to 6 was applied to a GC-AED analyzer to analyze the residual sulfur content. The results are shown in Table 5.

[0071]

[Table 5]

[0072]

According to the catalyst of the present invention, the desulfurization specific activity obtained from reaction conditions and rate constants is remarkably higher than that of conventional catalysts, and the excellent hydrogenation ability of tungsten makes it difficult to desulfurize sulfur. The compound can also exhibit excellent desulfurization performance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Osamu Chiyoda 1641-503 Kamitakano, Satte City, Saitama Prefecture (72) Inventor Kaiji Usui 1-62-10 Iwana, Noda City, Chiba Prefecture

Claims (1)

[Claims] 1. On an inorganic oxide support, one or both of cobalt and nickel, based on the catalyst, is 1 to 10% by weight in terms of oxide, and molybdenum is 10 to 10 in terms of oxide.
25% by weight, and a light oil characterized in that tungsten is supported so that the weight ratio of tungsten to molybdenum is 0.01 to 0.2 in terms of oxide, and the average pore diameter of the catalyst is 60 to 90Å. Hydrodesulfurization catalyst.