JP3676849B2 - Gas oil hydrodesulfurization catalyst - Google Patents

Description

【００６４】
【表２】

【００６５】
以上の実施例１〜８および比較例１〜６で調製した触媒Ａ〜Ｐを用いて、軽油の水素化脱硫反応を、表２に示す反応条件で行った。
【００６６】
【表３】

【００６７】
触媒の性能評価は、上記の反応条件により運転し、１００時間通油後の硫黄含有量を測定し、下記の式に基づいて反応速度定数を求め、触媒Ｋの値を１００とした相対評価で行った。結果は表４に示した。
【００６８】
【数１】

【００６９】
【表４】

【００７０】
また、以上の実施例１〜８および比較例１〜６で調製した触媒Ａ〜Ｐを使用して得られた生成油をＧＣ−ＡＥＤ分析器にかけて残存硫黄分の分析を行った。その結果を表５に示した。
【００７１】
【表５】

【００７２】
【発明の効果】
本発明の触媒によれば、反応条件、速度定数から求めた脱硫比活性が、従来の触媒に比較して著しく高く、またタングステンの優れた水素化能力により、難脱硫性硫黄化合物にも優れた脱硫性能を発揮することができる。[0001]
[Industrial application fields]
The present invention relates to a hydrodesulfurization catalyst for light oil that can effectively remove sulfur compounds that are hardly desulfurized in a deep desulfurization region.
[0002]
[Prior art]
Hydrocarbon oil generally contains sulfur compounds, and when these oils are used as fuel, sulfur present in the sulfur compounds is converted into sulfur compounds and discharged into the atmosphere.
Therefore, it is desirable that the sulfur content in the hydrocarbon oil be as small as possible in consideration of air pollution when combusted.
Reduction of the sulfur content can be achieved by catalytic hydrodesulfurization of the hydrocarbon oil.
[0003]
In addition, due to environmental problems, regulations on sulfur contained in commercial diesel oil become more stringent (regulated from the conventional 0.2 wt% to 0.05 wt%), and further deep desulfurization is required. In this region, it is necessary to treat difficult-to-desulfurize substances mainly composed of 4-MDBT (4-methyldibenzothiophene) and 4,6-DMDBT (4,6-dimethyldibenzothiophene), which are considered to be hardly-desulfurized substances. .
[0004]
Catalysts used for hydrodesulfurization intended for such deep desulfurization include metals in Group VI of the periodic table (hereinafter referred to as “Group 6”) and Group VIII in the periodic table (hereinafter referred to as “Group 8”). A metal is an active metal and is a catalyst supported on an oxide carrier such as alumina, magnesia, silica, etc. Generally, Mo is used as the Group 6 metal, and Co or the like as the Group 8 metal. Ni is used.
Furthermore, addition of phosphorus, boron or the like has been reported to improve the activity of this catalyst (Japanese Patent Laid-Open No. 52-13503).
[0005]
In addition, a technique in which tungsten is mixed into a group 6 and group 8 combined catalyst as hydrodesulfurization of hydrocarbon oil has been reported (Applied Catalysis A: General 109 (1994) 195 to 210). The technology is mainly aimed at deasphaltening heavy oil, not deep desulfurization of light oil, or desulfurization of difficult-to-desulfurize substances.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a hydrodesulfurization catalyst for light oil having excellent desulfurization activity in a deep desulfurization region.
[0007]
[Means for Solving the Problems]
As a result of repeated studies to achieve the above object, the present inventors
(1) Focusing on the effect of tungsten on the hydrogenation of hard-to-desulfurize sulfur compounds, cobalt-molybdenum catalyst or nickel-, which is a conventional hydrodesulfurization catalyst of a combined group 6-group 8 When molybdenum is supported on the molybdenum catalyst at a specific ratio with respect to molybdenum, the one having a specific average pore diameter can effectively remove the hardly-desulfurizable sulfur compound in the deep desulfurization region,
(2) This hydrodesulfurization is to effectively remove partially desulfurization substances such as 4-MDBT and 4,6-DMDBT by partial nuclear hydrogenation,
As a result, the present invention has been completed.
[0008]
That is, the present invention provides, on an inorganic oxide support, on the basis of a catalyst, both and / or one of cobalt and nickel is 1 to 10% by weight in terms of oxide, molybdenum is 10 to 25% by weight in terms of oxide, and A hydrodesulfurization catalyst for light oil, wherein 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 90 mm Is the gist.
[0009]
The support of the catalyst of the present invention is a crystalline inorganic oxide.
Various inorganic oxides can be used, such as 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-tria, silica-alumina-zirconia, silica-alumina-magnesia, silica-magnesia-zirconia, etc. These can be used alone or in combination of two or more.
[0010]
Among these inorganic oxides, preferred are alumina, silica-alumina, alumina-titania, alumina-boria, and alumina-zirconia, with γ-alumina being particularly preferred.
[0011]
The above support (or the catalyst of the present invention comprising the above support) contains one or more clay minerals such as montmorillonite, kaolin, halosite, bentonite, adabargaite, bauxite, kaolinite, nacrite, and anoxite. May be.
[0012]
The specific surface area of the support composed of these inorganic oxides is not particularly limited, but is preferably 250 m ² / g or more.
The pore volume of the carrier is not particularly limited, but is preferably 0.4 to 1.2 cc / g.
The average pore diameter of the support is not particularly limited, but when the average pore diameter of the catalyst of the present invention is 60 to 90 mm, it is preferable to use a catalyst having a diameter of 50 to 130 mm.
[0013]
The catalyst of the present invention is obtained by supporting a specific amount of cobalt and / or nickel, molybdenum, and tungsten on the support.
[0014]
The supported amount of either or both of cobalt and nickel is 1 to 10% by weight, preferably 3 to 7% by weight in terms of oxide, based on the catalyst.
When both and / or one of cobalt and nickel is less than 1% by weight, hydrodesulfurization activity does not appear, and even if it exceeds 10% by weight, the corresponding improvement in activity cannot be obtained. Disadvantageous.
[0015]
The supported amount of molybdenum 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 acting as an active site becomes too small and hydrodesulfurization activity does not appear. If it is more than 25% by weight, the metal molybdenum aggregates and the active site is reversed. As a result, the hydrodesulfurization activity decreases.
[0016]
The supported amount of tungsten is such that the weight ratio of tungsten to the above molybdenum is WO ₃ : MoO ₃ = 0.01: 1 to 0.20: 1, preferably 0.02: 1 to 0.1: 1, The amount is preferably 0.04: 1 to 0.07: 1.
When the WO ₃ : MoO ₃ weight ratio (hereinafter simply referred to as “ratio”) is less than 0.01, the above-described nuclear hydrogenation activity of the hardly desulfurizable substance does not appear, and the weight ratio of molybdenum to tungsten is 0. If more than 2, the amount of tungsten to be supported is too large, and the metal tungsten agglomerates as in the case of the above-mentioned molybdenum, the number of active sites is reduced, and the removal efficiency of the difficult-to-desulfurize substance in hydrodesulfurization. Will fall.
[0017]
There is no particular limitation on the method or the order in which cobalt or nickel, molybdenum, or tungsten is supported on the inorganic oxide carrier.
For example, (1) impregnation support of molybdenum salt solution, then impregnation support of cobalt salt and / or nickel salt solution, followed by impregnation support of tungsten salt solution, (2) first of molybdenum salt solution Impregnation support, followed by impregnation support of tungsten salt solution, followed by impregnation support of cobalt and / or nickel salt solution, (3) First impregnation support of tungsten salt solution, then impregnation support of molybdenum salt solution Then, impregnation and support of either or both of cobalt and nickel may be performed. (4) First, the molybdenum salt solution and the tungsten salt solution are simultaneously impregnated and supported, and then either or both of cobalt and nickel are supported. The salt solution may be impregnated and supported.
[0018]
After these impregnations, if dried and calcined, it becomes a catalyst of the present invention. At this time, when each active ingredient is supported so that the above-mentioned impregnation of each solution is divided into a plurality of times to achieve the above-mentioned loading amount, A dry firing step may be provided between the impregnation steps.
[0019]
When each active ingredient is supported by the above impregnation method, various salts of cobalt or nickel can be used, for example, carbonate, acetate, nitrate, lead sulfate, phosphate, etc. These salts can be used alone or in combination of two or more.
[0020]
Various salts of molybdenum can be used, such as ammonium molybdate ((NH ₄ ) ₆ Mo ₇ O ₂₄ · 4H ₂ O), molybdophosphoric acid (H ₃ (PMo ₁₂ O ₄₀ ) · 30H ₂ O), Examples thereof include molybdenum oxide (MoO ₃ ), and these salts can be used alone or in combination of two or more.
[0021]
Various tungsten salts 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 · 8H ₂ O), tungstic acid (H ₂ WO ₄ ), tungstophosphoric acid (H ₃ (PW ₁₂ O ₄₀ ) · 30H ₂ O), and the like. These salts may be used alone or in combination of two or more. Can be used in combination.
[0022]
The solvent for dissolving the molybdenum salt, the tungsten salt, and the cobalt or nickel salt is not particularly limited, and various solvents can be used, for example, water, alcohols, ethers. , Ketones, aromatics, etc., preferably water, acetone, methanol, n-propanol, i-propanol, n-butanol, i-butanol, hexanol, benzene, toluene, xylene, diethyl ether, tetrahydrofuran, Dioxane and the like, particularly preferably water.
[0023]
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. In consideration of easiness, the amount of the solvent in each of these impregnation operations is 50 to 150 g, preferably 70 to 90 g, based on 100 g of the carrier (the impregnation is divided into a plurality of times and dried and fired between the respective impregnation steps. In the case of providing a process, it is appropriate that the amount of the solvent in each impregnation step and each drying and firing step is set to this amount). What is necessary is just to set it as the ratio which becomes the quantity of the oxide conversion mentioned above with respect to a catalyst.
[0024]
Each impregnation condition for impregnating each of the above solutions is not particularly limited. Usually, the temperature is 10 to 100 ° C, preferably 10 to 50 ° C, more preferably 15 to 30 ° C. At this time, it is preferable to involve stirring.
The time (in the case where 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.
[0025]
The catalyst of the present invention is subjected to an impregnation operation of each of the above solutions under the above conditions (when the impregnation is divided into a plurality of times and a dry calcination step is provided between the respective impregnation steps, a total impregnation step and a total dry calcination step). The carrier carrying each active ingredient is further dried and fired.
[0026]
The drying at this time (including the drying when the impregnation is divided into a plurality of times and the drying and firing step is provided between the impregnation steps) is performed by various drying methods such as air drying, hot air drying, heat drying, freeze drying and the like. be able to.
[0027]
The temperature during firing (including each firing in the case where the impregnation is divided into a plurality of times and a drying firing step is provided between the impregnation steps) is 400 to 500 ° C., preferably 450 to 500 ° C., and time (When the impregnation is divided into a plurality of times and a drying and firing step is provided between the impregnation steps, the time for each firing step) is suitable for 2 to 10 hours, preferably 3 to 5 hours.
[0028]
In the catalyst of the present invention prepared as described above, the specific surface area and pore volume are not particularly limited as long as they can function as a catalyst, but in order to effectively remove the hardly desulfurizing substance. The specific surface area is preferably 200 m ³ / g or more, and the pore volume is preferably 0.4 to 1.2 cc / g.
[0029]
The average pore diameter is 60 to 90 mm, preferably 70 to 80 mm.
When the average pore diameter is less than 60 mm, the reactants hardly diffuse into the pores. Therefore, the nuclear hydrogenation reaction of the hardly-desulfurizable substance does not occur effectively, and the physical properties necessary for functioning as a catalyst ( When trying to obtain a specific surface area and a pore volume, problems such as insufficient mechanical strength occur in production.
[0030]
If it is larger than 90 mm, the diffusibility of the reactant into the pores is good, but the effective surface area of the catalyst becomes small, so that it is difficult to remove the hardly desulfurizable substance.
More specifically, when performing a deep desulfurization reaction, it is important to reduce the sulfur content to a predetermined level or less without deteriorating the hue of the produced light oil. Many. In this case, since the contact time becomes long, it is not necessary to improve the diffusibility of the reactant by using a catalyst having an average pore diameter larger than 90 mm, and conversely, a catalyst having an average pore diameter larger than 90 mm. If used, the contact effect between the reaction substance diffused in the pores and the reaction surface is lowered, and the improvement of the activity is not recognized.
[0031]
The pore size distribution of the catalyst (that is, the proportion of pores having an average pore size of ± 15 mm) is 70% or more, preferably 80% or more.
When the pore size distribution value is small and the distribution curve is broad, the number of effective pores is relatively small even if the average pore size is an ideal value. I can not expect.
[0032]
The shape of the catalyst of the present invention is not particularly limited, and can be various shapes used for ordinary catalyst shapes. For example, a four-leaf type or a cylindrical shape can be used.
The size of the catalyst of the present invention is usually 1/10 to 1/22 inch.
[0033]
The catalyst of the present invention may be used by mixing with a known catalyst or a known inorganic oxide support.
[0034]
Examples of the feed oil that can be hydrodesulfurized using the catalyst of the present invention include straight-run gas oil obtained by atmospheric distillation of crude oil, cracked gas oil produced from a catalytic cracker, and vacuum gas oil obtained by vacuum distillation. In general properties, the boiling point is 150 to 600 ° C., preferably 200 to 400 ° C., the sulfur content is 3% by weight or less, preferably 2.5% by weight or less, and the density (15 ° C.) is 0.94 g / cm ^3. The following are preferred.
[0035]
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, moving bed or fluidized bed, into which gas oil to be desulfurized is introduced, and the high temperature and high pressure ( The desired desulfurization is carried out under a substantial hydrogen partial pressure).
Most commonly, the catalyst is maintained as a fixed bed so that light oil passes down the fixed bed.
The catalyst can be used in a single reactor or even in several successive reactors. In particular, when the feed oil is a relatively heavy light oil, it is preferable to use a multistage reactor.
[0036]
As a preferred example of the reaction, the gas oil has a temperature of about 200 to 500 ° C., more preferably about 250 to 400 ° C., and a liquid space velocity of about 0.05 to 5.0 hr ⁻¹ , more preferably about 0.1. The catalyst is brought into contact with the catalyst at ˜4.0 hr ⁻¹ and a hydrogen partial pressure of about 10 to 200 kg / cm ² G, more preferably about 30 to 100 kg / cm ² G.
[0037]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited at all by these.
[0038]
Example 1
In an Erlenmeyer flask, 32.7 g of ammonium molybdate was dissolved in 75 g of water, and ammonia water was further added and stirred until the ammonium molybdate was completely dissolved to prepare an aqueous solution of ammonium molybdate.
[0039]
In another Erlenmeyer flask, 26 g of cobalt nitrate was dissolved in 75 g of water and stirred to prepare an aqueous solution of cobalt nitrate.
[0040]
In yet another Erlenmeyer flask, 2.6 g of ammonium metatungstate was dissolved in 75 g of water so that the WO ₃ / MoO ₃ ratio in the catalyst as the final product of this example was 0.05 and stirred. An aqueous solution of ammonium metatungstate was prepared.
[0041]
The ammonium molybdate aqueous solution was impregnated in 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 85 mm in an eggplant type flask.
The impregnation temperature was normal temperature and the impregnation time was 1 hour.
Then, it was dried (air-dried) and baked at 500 ° C. for 4 hours in a muffle furnace to complete the first stage of impregnation support (impregnation support of molybdenum salt solution).
[0042]
After completion of the first stage of impregnation, the catalyst is impregnated with an aqueous cobalt nitrate solution in an eggplant type flask under the same conditions as the first stage of impregnation, and dried and fired under the same conditions as the first stage of dry firing. Then, the second stage of impregnation support (cobalt salt solution impregnation support) was completed.
[0043]
The catalyst after completion of the second stage of impregnation is impregnated with an ammonium metatungstate aqueous solution in the eggplant type flask under the same conditions as the first stage of impregnation, and dried under the same conditions as the first stage of drying and firing. After calcination, the third stage of impregnation support (impregnation support of the tungsten salt solution) was completed, and catalyst A was prepared.
[0044]
Example 2
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 supported on the second stage.
[0045]
Example 3
16.3 g is used instead of 32.7 g of ammonium molybdate supported on the first stage, and tungstic acid is used so that the WO ₃ / MoO ₃ ratio becomes 0.02 instead of cobalt nitrate supported on the second stage. Similar to Example 1 except that 0.236 g was used, an aqueous solution in which ammonia water was added until it completely dissolved, and 26 g of cobalt nitrate was used instead of ammonium metatungstate supported on the third stage of impregnation. Catalyst C was prepared by the method described above.
[0046]
Example 4
6.47 g of tungstophosphoric acid is used instead of the first stage impregnated ammonium molybdate, and molybdic acid is used so that the WO ₃ / MoO ₃ ratio is 0.02 instead of the second stage impregnated supported cobalt nitrate. Catalyst D was prepared in the same manner as in Example 1, except that 40.9 g of ammonium was used and 26 g of cobalt nitrate was used instead of metatungstic acid supported on the third stage of impregnation.
[0047]
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, and these ammonium molybdate and ammonium paratungstate were dissolved. Ammonium water was added until and completely dissolved, and the mixture was stirred to prepare a mixed aqueous solution of ammonium paratungstate and ammonium molybdate.
[0048]
In another Erlenmeyer flask, 26 g of cobalt nitrate was dissolved in 75 g of water and stirred to prepare an aqueous solution of cobalt nitrate.
[0049]
In an eggplant type flask, the above mixed aqueous solution of ammonium paratungstate and ammonium molybdate was impregnated and dried and fired on 100 g of the same γ-alumina carrier as that used in Example 1 under the same conditions as in Example 1. First stage impregnation support (impregnation support of tungsten salt and molybdenum salt) was performed.
[0050]
The cobalt nitrate aqueous solution is impregnated into the catalyst after completion of the first stage impregnation support in an eggplant type flask under the same conditions as the first stage impregnation operation, and under the same conditions as the first stage drying and firing. After drying and firing, the second stage of impregnation support (cobalt salt solution impregnation support) was completed, and catalyst E was prepared.
[0051]
Example 6
The same method as in Example 5 except that 3.8 g of ammonium metatungstate was used so that the WO ₃ / MoO ₃ ratio was 0.07 instead of 0.97 g of ammonium paratungstate supported on the first stage. Catalyst F was prepared.
[0052]
Example 7
A catalyst G was prepared in the same manner as in Example 1, except that 32.7 g of ammonium molybdate supported on the first stage was replaced with 24.5 g so that the WO ₃ / MoO ₃ ratio was 0.07. did.
[0053]
Example 8
Catalyst H was prepared in the same manner as in Example 1 except that 13 g of cobalt nitrate and 13 g of nickel nitrate were used instead of 26 g of cobalt nitrate supported on the second stage.
[0054]
Example 9
Catalyst I was prepared in the same manner as in Example 1 except that a γ-alumina support having a specific surface area of 358 m ² / g, a pore volume of 0.54 cc / g and an average pore diameter of 53 mm was used.
[0055]
Example 10
Catalyst J was prepared in the same manner as in Example 1 except that a γ-alumina support having a specific surface area of 241 m ² / g, a pore volume of 0.75 cc / g, and an average pore diameter of 92 mm was used.
[0056]
Comparative Example 1
Catalyst K was prepared in the same manner as in Example 1 except that the third stage impregnation was not carried.
[0057]
Comparative Example 2
13.1 g was used instead of 32.7 g of ammonium molybdate supported on the second stage of impregnation, and the WO ₃ / MoO ₃ ratio was changed to 0.05 instead of 2.6 g of ammonium metatungstate supported on the third stage of impregnation. Thus, catalyst L was prepared in the same manner as in Example 1 except that 0.92 g was used.
[0058]
Comparative Example 3
49.1 g was used instead of 32.7 g of ammonium molybdate supported on the second stage of impregnation, and the WO ₃ / MoO ₃ ratio was changed to 0.05 instead of 2.6 g of ammonium metatungstate supported on the third stage of impregnation. Thus, catalyst M was prepared in the same manner as in Example 1 except that 4.7 g was used.
[0059]
Comparative Example 4
Catalyst N was prepared in the same manner as in Example 1, except that 0.27 g of WO ₃ / MoO ₃ ratio was 0.005 instead of 2.6 g of ammonium metatungstate supported on the third stage of impregnation. Was prepared.
[0060]
Comparative Example 5
The catalyst O was prepared in the same manner as in Example 1 except that 14.0 g was used so that the WO ₃ MoO ₃ ratio was 0.25 instead of 2.6 g of ammonium metatungstate supported on the third stage. Prepared.
[0061]
Comparative Example 6
Catalyst P was prepared in the same manner as in Example 1, except that a γ-alumina support having a specific surface area of 190 m ² / g, a pore volume of 0.71 cc / g, and an average pore diameter of 101 mm was used.
[0062]
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 the properties are shown in Table 2.
[0063]
[Table 1]

[0064]
[Table 2]

[0065]
Using the catalysts A to P prepared in Examples 1 to 8 and Comparative Examples 1 to 6 described above, hydrodesulfurization reaction of light oil was performed under the reaction conditions shown in Table 2.
[0066]
[Table 3]

[0067]
The performance evaluation of the catalyst is performed under the above reaction conditions, the sulfur content after 100 hours of oil passing is measured, the reaction rate constant is obtained based on the following formula, and the value of the catalyst K is set to 100. went. The results are shown in Table 4.
[0068]
[Expression 1]

[0069]
[Table 4]

[0070]
Moreover, the produced | generated oil obtained using the catalysts AP prepared in the above Examples 1-8 and Comparative Examples 1-6 was applied to the GC-AED analyzer, and the residual sulfur content was analyzed. The results are shown in Table 5.
[0071]
[Table 5]

[0072]
【The invention's effect】
According to the catalyst of the present invention, the desulfurization specific activity obtained from the reaction conditions and rate constant is remarkably high as compared with the conventional catalyst, and the excellent hydrogenation ability of tungsten is excellent for the hardly desulfurization sulfur compound. Desulfurization performance can be demonstrated.

Claims (1)

On the inorganic oxide support, on a catalyst basis, one or both of cobalt and nickel is 1 to 10% by weight in terms of oxide, molybdenum is 10 to 25% by weight in terms of oxide, and the weight ratio of tungsten to molybdenum A hydrodesulfurization catalyst for light oil, characterized in that tungsten is supported so as to be 0.01 to 0.2 in terms of oxide, and the average pore diameter of the catalyst is 60 to 90 mm.