JPH081008A - Wax isomerization catalyst, wax isomerization method, and lubricating base oil production method - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] A wax isomerization catalyst with high resistance to sulfur and nitrogen, and a lubricant base oil with high viscosity index and low pour point in high yield using the catalyst. To provide a method for isomerizing wax. [Structure] A carrier prepared by mixing 1 to 30% by weight of crystalline molecular sieve with alumina having pores with a major axis of 6.5 to 7.5Å and a SiO ₂ / Al ₂ O ₃ molar ratio of 50 or more. , At least one selected from Group 8 metals and Group 6A of the Periodic Table
A catalyst for wax isomerization comprising supporting various metal components, and a wax isomerization method comprising contacting a wax hydrocarbon oil containing 50% by weight or more of paraffin with the catalyst under hydrogen pressure, In addition, the lubricating base oil production intermediate and the slack wax are alternately passed through the reactor filled with the catalyst, and the hydrorefining of the lubricating base oil production intermediate and the slack wax isomerization are alternately performed. Become.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a catalyst suitable for producing a lubricating base oil having a high viscosity index by isomerizing a wax-based hydrocarbon oil, particularly a slack wax, and a wax using the catalyst. The present invention relates to an isomerization method and a method for producing a lubricating base oil.

[0002]

2. Description of the Related Art Lubricating base oils having a high viscosity index can be produced by isomerizing slack wax or performing selective hydrocracking, and various methods, catalysts and the like have been proposed. . Among them, as a method for producing a lubricating oil having a high viscosity index, a refractory oxide, specifically, alumina is used as a carrier, and nickel and / or cobalt, molybdenum and / or tungsten and phosphorus oxide are supported on the carrier. A method using a catalyst has been proposed (Japanese Patent Publication No. 54-2204). However, the method using this catalyst has a drawback that the reaction rate of isomerization is low and only a low yield of lubricating base oil can be obtained.

Therefore, in order to increase the reaction rate and improve the yield of lubricating base oil, methods using various catalysts have been proposed.

For example, air-pore zeolite (ZSM-5,
(22, 23, 35) or a low acid zeolite having an alpha value not exceeding 20 (zeolite β containing boron in the skeleton) and carrying a hydrogenation / dehydrogenation component such as palladium or platinum (JP-A-62- 112691, JP-A-5-504597, JP-A-4-226593), a catalyst in which platinum or palladium is supported on a silicoaluminophosphate molecular sieve having an intermediate pore diameter (JP-A-62-25195, Japanese Patent Laid-Open No. 4-5033
No. 71) are presented.

Further, a catalyst in which platinum or the like is supported on a fluorinated refractory metal oxide carrier (JP-A-1-223196) or platinum or the like is supported on a refractory metal oxide carrier treated with tetraammonium aluminate or the like. Catalyst (JP-A-60-
No. 133089) is disclosed.

However, the lubricating base oil obtained by using this type of catalyst may not be sufficient for use as a fuel-saving motor oil in terms of pour point or viscosity index, and further, these catalysts may be used. Most of the is sulfur,
A noble metal having a low resistance to nitrogen is used as an active supporting metal, and it has a drawback that the sulfur and nitrogen contents in the raw material must be strictly controlled. Therefore, in order to produce a base oil having a high viscosity index by isomerizing a wax or the like using a catalyst on which these precious metals are supported, desulfurization,
A separate reactor for denitrification is required.

Further, a catalyst using zeolite, silicoaluminophosphate / molecular sieve or the like has a drawback that it is more expensive than an alumina carrier catalyst.
In addition, the refractory metal oxide carrier treated with fluorine or tetraammonium aluminate complicates the catalyst manufacturing process, and uses a harmful reagent such as fluorine, which causes problems such as ensuring manufacturing safety. there were.

[0008]

DISCLOSURE OF THE INVENTION The present invention is to solve the above problems, and an object of the present invention is to prepare a wax isomerization catalyst which can be prepared by a simple method and has high resistance to sulfur and nitrogen and high versatility, and Using the catalyst, a method for isomerizing a wax to obtain a lubricating base oil having a high viscosity index of 140 or more and a low pour point in a high yield, as well as ordinary refining of a lubricating oil raw material and a high viscosity index from slack wax It is an object of the present invention to provide a method for producing a lubricating base oil, which can alternately produce a lubricating oil.

[0009]

[Means for Solving the Problems] In order to promote isomerization rapidly on a bifunctional catalyst in which a metal is supported on a refractory oxide support, the dehydrogenation / hydrogenation activity of the metal and the acidity of the support are required. It is said that the degree must be raised in a balanced manner. For example, when zeolite is used as a carrier for the purpose of increasing acidity, the decomposition reaction is prioritized, and a base oil having a low viscosity index can be obtained only in a low yield. As a measure for suppressing this decomposition activity, a crystalline molecular sieve having a specific pore size is used to selectively decompose or isomerize by utilizing the molecular sieving effect, or the crystalline molecular sieve SiO _{2 is used.} There is known a method of using a material having a high / Al ₂ O ₃ ratio and a low acidity. Further, for the purpose of enhancing the dehydrogenation / hydrogenation activity, a noble metal having a high dehydrogenation / hydrogenation activity, particularly platinum, has been favorably used as a supported metal. This is because when a crystalline molecular sieve is mainly used, a noble metal component such as platinum is essential in the balance between metal dehydrogenation / hydrogenation activity and carrier acidity, and the use of base metals such as nickel is restricted. Is preferred (eg ACS preprint 3
8 (4) 788, 1993).

However, surprisingly, even if a small amount of crystalline molecular sieve is added to alumina, its molecular sieving function is sufficiently exhibited, and the acidity of the crystalline molecular sieve is the same as that of the carrier. I found that it is reflected. Moreover, a carrier having a specific pore diameter, and a crystalline molecular sieve having a low acidity by increasing the SiO ₂ / Al ₂ O ₃ ratio above a certain level is added to alumina.
In addition to a metal having an extremely high hydrogenation ability such as a noble metal such as palladium or platinum, a Group 8 base metal or a Group 6A metal used in a general hydrorefining catalyst is supported,
It was found that the dehydrogenation / hydrogenation activity and the acidity of the carrier are well balanced, and the isomerization of wax progresses rapidly.

The present invention has been made on the basis of such findings. The present invention has alumina having pores having a major axis of 6.5 to 7.5Å and a SiO ₂ / Al ₂ O ₃ molar ratio of 50 or more. A wax isomerization catalyst comprising a carrier prepared by mixing 1 to 30% by weight of a crystalline molecular sieve and carrying at least one metal component selected from Group 8 metal and Group 6A of the Periodic Table, and A wax isomerization method comprising contacting a wax hydrocarbon oil containing 50% by weight or more of paraffin with the wax isomerization catalyst under hydrogen pressure, and a reactor filled with the wax isomerization catalyst is lubricated. A method for producing a lubricating base oil, which comprises alternately passing a base oil producing intermediate and a slack wax to alternately perform hydrorefining of the lubricating base oil producing intermediate and slack wax isomerization. .

Alumina hydrate is included in the alumina used in the present invention, and any alumina that is usually used as a catalyst carrier or any alumina hydrate can be used without any particular problems. Can be used without.

The crystalline molecular sieve used in the present invention must be a crystalline molecular sieve having a major axis of 6.5 to 7.5Å. Pore major axis is 6.
If it is less than 5Å, only linear paraffins and branched paraffins having a small degree of branching will be decomposed and the isomerization reaction will not proceed. In this case, so-called wax-containing oil, which contains a large amount of components other than paraffin, is suitable for simply lowering the pour point, but when wax is used as the raw material, the dewaxing treatment that is subsequently performed. In, the yield of lubricating base oil is significantly reduced. On the other hand, when the major axis of the pores is larger than 7.5 Å, the molecular sieving function for wax is substantially lost, and only a base oil having a low lubricating base oil fraction yield and a low viscosity index can be obtained.

Crystalline molecular sieves having a major axis of 6.5 to 7.5Å include zeolites L, Y, Ω, mordenite, and silicoaluminophosphate molecular sieves (SAPO) which are zeolite-like compounds. Any of can be used. But of these,
Zeolite Y has pores with a pore size of 7.4Å, but it is not preferable for wax isomerization because it has secondary decomposition due to its channel structure.

Further, the crystalline molecular sieve needs to have a low acidity, and therefore SiO ₂ / A
An l ₂ O ₃ molar ratio of 50 or more is used. SiO ₂ / Al ₂ O ₃
If the molar ratio is less than 50, even if a small amount is added, the cracking activity is too high to obtain a low base oil fraction yield of a lubricating base oil and a base oil having a low viscosity index. Deactivation is severe and catalyst life becomes short.

The shape of the crystalline molecular sieve is not particularly limited, but it is 100 μm or less, preferably 0.1 to 50 μm.
It is preferable to use those having a median diameter of.
The amount of crystalline molecular sieve added to alumina is 1 to 30 wt%. This is because if the amount of the crystalline molecular sieve added is less than 1 wt%, the isomerization activity is low, and if it exceeds 30 wt%, the decomposition activity is high and the isomerization selectivity is low. The molecular sieving function and the acidity of the crystalline molecular sieve are sufficiently exerted even with a small amount of addition. Further, as described above, the relatively small amount of the crystalline molecular sieve added to the alumina enables the use of the Group 8 base metal and the Group 6A metal as the metal hydride component.

The supported metal is a metal hydride component used in a general hydrorefining catalyst, and is a periodic table No. 8
Group 1 base metals and Group 6A metals such as nickel, cobalt, molybdenum, and tungsten are used alone or in combination of two or more. The amount of these metals supported is a total amount as a metal component with respect to the catalyst, preferably 3 to 30% by weight, and particularly preferably 10 to 20% by weight. Generally, when using crystalline molecular sieves such as zeolite as the catalyst support,
It was thought that a noble metal having a high hydrogenating ability was required to achieve a good balance between the acidity and the dehydrogenating / hydrogenating activity of the metal hydride component. However, in a carrier obtained by adding a small amount of crystalline molecular sieve to alumina in an amount of 1 to 30% by weight, if the molecular sieve has an appropriate pore structure and acidity, the acidity of the carrier as a whole is moderately weakened. As a result, even with base metals, isomerization proceeds rapidly.

In addition to these metal components, other elements such as phosphorus may be supported. Other elements such as phosphorus may be appropriately selected within the range of 1 to 7% by weight.

The catalyst of the present invention can be prepared as follows.

First, alumina and crystalline molecular sieves are mixed and kneaded. This may be carried out by mixing both before kneading, or by adding and mixing the crystalline molecular sieve while kneading alumina. . There is no need to do anything special for this mixing, only mechanical mixing is required. In this kneading, it is preferable to use a 1-5% nitric acid solution as a peptizing agent. Further, in kneading, any known kneader can be used. After kneading, it may be molded using an extruder or the like. The shape in this case is
It is preferable to mold it in consideration of the reactor to be used, such as a cylindrical shape, a three-lobed shape, and a spherical shape, and it is preferable to have a maximum sectional diameter of 1/16 to 1/32 inch.

Next, this molded product is dried at a temperature of 50 to 200 ° C. for 5 to 24 hours and calcined in the air at a temperature of 250 to 800 ° C., preferably 400 to 700 ° C. for 1 to 2 hours. . The refractory oxide carrier thus obtained is loaded with the above-mentioned metal component by an impregnation method or the like,
Dry at a temperature of 200 ° C. for 5 to 24 hours, and 250 to 70
At a temperature of 0 ° C, preferably 400-600 ° C,
Bake in air for 0.5-2 hours.

The catalyst of the present invention obtained as described above is preferably used for isomerizing a wax type hydrocarbon oil containing 50% by weight or more of paraffin as a raw material.
The wax type hydrocarbon oil containing 50% by weight or more of paraffin is not particularly limited in its kind, but it is a slack wax obtained in a solvent dewaxing step which is one of the lubricating oil production steps, that is, a reduced pressure intermediate quality. The slack wax obtained by subjecting a heavy fraction or a deasphalted oil of reduced pressure residue to a furfural solvent extraction treatment and then a hydrorefining apparatus or a solvent dewaxing apparatus without treatment is suitable. Used. These waxes may be treated individually for each fraction, or may be used as a mixture with those of other fractions.

This isomerization can be carried out in any of a fixed bed, a moving bed and a fluidized bed, a temperature of 300 to 400 ° C., a hydrogen pressure of 50 to 150 kg / cm ^{2, and} a pressure of 500 to 3000.
It is preferable to carry out under the reaction conditions of a hydrogen / wax ratio of 1 / l and a liquid hourly space velocity (LHSV) of 0.2 to 5.0 hr ⁻¹ .

In order to obtain a lubricating base oil having a high viscosity index in a high yield, the linear paraffin conversion is 90% or more,
It is preferable to set the reaction conditions so that the conversion to a light fraction having a boiling point not higher than the initial boiling point of the raw material is 40% by weight or less. When the linear paraffin conversion does not reach 90%, a high viscosity index can be expected, but the yield of the lubricating base oil decreases in the subsequent dewaxing treatment, and the pour point of the lubricating base oil is sufficiently high. It may not be possible to lower it. On the other hand, when the conversion to light components exceeds 40% by weight, the yield of the lubricating base oil fraction is low and a high viscosity index cannot be maintained, which is not preferable.

The product oil obtained by this isomerization reaction contains a light fraction which is not desirable as a lubricating base oil.
This is separated by distillation or the like. It is desirable to carry out this distillation under reduced pressure, and it is advisable to remove a fraction having a boiling point of 350 ° C. or lower to obtain a residue having an initial boiling point of 330 to 370 ° C.

After distilling the isomerized product, it can be made into a lubricating base oil by subjecting it to a dewaxing apparatus. Dewaxing in this case may be solvent dewaxing which is generally performed. For example, a mixed solvent of methyl ethyl ketone / toluene (for example, 1/1 solvent ratio) is used, and a solvent / dewaxing raw material ratio of 2 /
It may be carried out at a temperature of -20 to -30 ° C in the range of 1 to 4/1.

Since the above-mentioned catalyst uses, as a supported metal, a metal hydride component such as those used in general hydrorefining catalysts, a group 8 base metal and a group 6A metal of the periodic table,
In addition to isomerization, it also has hydrorefining ability such as desulfurization and denitrification. Therefore, the present catalyst can also be used for hydrorefining a conventional intermediate for producing a lubricating base oil, such as a vacuum distillation fraction of mineral oil. Therefore, conventionally, isomerization and hydrorefining were carried out in separate reactors, but by using this catalyst, it is possible to pass the usual lubricating base oil production intermediate and wax alternately in one reactor. Thus, hydrorefining and isomerization can be performed alternately.

The above-mentioned conventional intermediate for producing a lubricating base oil is an intermediate generally obtained in a step for producing a lubricating base oil, and typically, a vacuum distillation fraction or a propane-deasphalted treated residue of a vacuum distillation residue. Or a solvent-refined raffinate and / or solvent-dewaxed oil or catalytically-dewaxed oil, or a mixture of two or more thereof, which has a sulfur content of 0.5 to 5% by weight. It is preferable to use a material containing a certain amount.

This hydrorefining is carried out under a hydrogen pressure of 50 to 150 kg / cm ² under a hydrogen / oil ratio of 100 to 2000 l / l and a hydrogen / oil ratio of 0.1.
It is recommended to carry out under the conditions of a liquid hourly space velocity (LHSV) of 5 to 5 hr ⁻¹ and a temperature of 250 to 400 ° C.

When the hydrorefining and the isomerization are alternately performed, the type of the feedstock oil supplied to the reactor is changed,
Then either reset the condition or reset the condition, then
After that, any method may be used to switch the raw material oil type. At the initial stage of switching from hydrorefining to isomerization, or conversely from isomerization to hydrorefining, the activity of the catalyst is not sufficiently exerted, so that a lubricating base oil having the desired properties cannot be obtained. The activity is restored within a short period of time, and the lubricating base oil having the desired properties can be obtained.

Also in this hydrorefining, a conversion to a light fraction occurs due to a cracking reaction which is a side reaction as in the case of isomerization, and the light fraction undesirably used as the lubricating base oil is removed. It is necessary to carry out, but for this distillation, a common rectification column can be used for both hydrorefining and isomerization. Further, after the hydrorefining, the dewaxing device may be usually subjected to the dewaxing apparatus similarly to the case after the isomerization, but the dewaxing conditions are not so different between the two and can be commonly used.

In addition, depending on the type of the lubricating base oil production intermediate used in this hydrorefining, a lubricating base oil having a viscosity index of 120 or less is generally obtained.

[0033]

【Example】

(Example 1) Preparation of catalyst Alumina powder (1564 g) was placed in a kneader and 1 l of a 3% aqueous solution of nitric acid was added as a deflocculating agent and kneaded for 30 minutes. 0
Å, 117.7 g of SiO ₂ / Al ₂ O ₃ molar ratio = 210) was added, and the mixture was further kneaded for 30 minutes. This kneaded product is 1.4 mmφ
Molded into a cylindrical shape with an extruder having a hole die, and
Dry overnight at 30 ° C. The dried product was calcined in a rotary kiln at 600 ° C. for 1 hour to obtain a catalyst carrier.

150 g of this carrier was impregnated with molybdenum, nickel and phosphorus using an impregnating solution containing 46.5 g of ammonium molybdate, 41.8 g of nickel nitrate hexahydrate and 19.6 g of phosphoric acid solution. This was dried at 130 ° C. overnight and then calcined at 500 ° C. for 30 minutes using a rotary kiln to obtain catalyst A.

Isomerization of Wax The catalyst A obtained above was charged into a fixed bed flow type reaction vessel,
After sulphating this catalyst, a heavy slack wax obtained by solvent dewaxing the heavy lubricating fraction after vacuum distillation (oil content 13% by weight, density 0.84 g / cm ³ , boiling point range 330 ˜600 ° C.) for isomerization. The reaction conditions are as follows: hydrogen pressure 80 kg / cm ² , hydrogen / wax ratio 1500 l / l, LHSV 0.5 hr ⁻¹ , temperature 350-38.
It was varied between 0 ° C. The obtained product oil was analyzed by gas chromatography, and the results are shown in Table 1. The linear paraffin reduction rate is the NP conversion rate, and the boiling point is 33%.
The production rate of the fraction lower than 0 ° C was expressed as the decomposition rate.

[0036]

[Table 1]

(Comparative Examples 1 to 3) In Example 1, instead of mordenite, commercially available silicalite (zeolite pore major diameter 5.6Å, SiO ₂ / Al ₂ O ₃ molar ratio = 250), and commercially available zeolite Catalysts B and C were prepared in the same manner as in Example 1 except that zeolite β having dealuminated β (zeolite pore major axis 7.6Å, SiO ₂ / Al ₂ O ₃ molar ratio = 141) was used, respectively. . Further, a catalyst D was prepared in the same manner as in Example 1 using a carrier of alumina alone without adding mordenite. After sulfiding these catalysts, the reaction temperature is shown in Table 2.
An isomerization experiment was conducted in the same manner as in Example 1 except that the procedure described in 1. was carried out. Table 2 shows the results.

[0038]

[Table 2]

While the catalyst A and the comparative catalyst B of the present invention achieved a high NP conversion and a low decomposition rate, the other comparative catalyst C had a high decomposition rate even at a high NP conversion rate. It has a drawback that the yield of the lubricating base oil fraction is low, and that the catalyst D has a drawback that the NP conversion is low despite the high temperature of 400 ° C.

The following two examples show that the catalyst A of the present invention is essentially superior to the comparative catalyst B in wax isomerization ability.

Example 2 The product obtained using the catalyst A of Example 1 at a reaction temperature of 361 ° C. was distilled under reduced pressure to remove light components, and a residue having an initial boiling point of 330 ° C. was obtained. Obtained.
Next, this residue was dewaxed using a mixed solvent of methyl ethyl ketone / toluene (1/1 solvent ratio) at a solvent / dewaxing raw material ratio of 4/1 and a temperature of -27 ° C. The yield of the lubricating base oil thus obtained and the properties of this base oil are shown in Table 3.

(Comparative Example 4) In Comparative Example 1, the produced oil using the catalyst B was obtained in the same manner as in Example 2 to obtain a lubricating base oil. Table 3 shows the oil yield in the dewaxing process and the properties of the base oil.

[0043]

[Table 3]

Table 3 shows that Catalyst A of the present invention inherently has excellent wax isomerization ability. That is, even if the comparative catalyst B achieved a high NP conversion and a low decomposition rate in Table 2, the decomposition reaction for the linear paraffin preferentially proceeded, so that the dewaxing treatment that directly represents the degree of isomerization was performed. The product obtained with the catalyst A of the present invention gives a base oil having a viscosity index of 145 with a high dewaxed oil yield, while a product having an extremely low oil content yield is obtained.

[0045]

INDUSTRIAL APPLICABILITY The wax isomerization catalyst of the present invention exhibits a high isomerization rate and a low decomposition rate without pretreatment of the raw material wax, so that a lubricating base oil having a high viscosity index can be obtained in a high yield. In addition to being able to do so, it has an exceptional effect that it can also be used for the production of general-purpose lubricating base oils.

Claims (5)

[Claims] 1. Alumina is mixed with 1 to 30% by weight of a crystalline molecular sieve having pores with a major axis of 6.5 to 7.5Å and a SiO ₂ / Al ₂ O ₃ molar ratio of 50 or more. On the carrier,
A wax isomerization catalyst comprising at least one metal component selected from Group 8 metal and Group 6A of the Periodic Table. 2. A wax isomerization catalyst, wherein the crystalline molecular sieve according to claim 1 is at least one selected from zeolite L, zeolite Ω, mordenite or silicoaluminophosphate molecular sieve. 3. A wax isomerization method comprising contacting a wax hydrocarbon oil containing 50% by weight or more of paraffin with the catalyst for wax isomerization according to claim 1 under hydrogen pressure. 4. A wax isomerization method, wherein the wax-based hydrocarbon oil according to claim 3 is a slack wax. 5. A lubricating base oil production intermediate is alternately passed through a reactor filled with the wax isomerization catalyst according to claim 1 to hydrorefining the lubricating base oil production intermediate. And a slack wax isomerization are alternately carried out.