JPH08259961A - Method of hydrocracking petroleum distillate - Google Patents

Abstract

PURPOSE: To obtain high-quality kerosene or gas oil in good yields by hydrotreating a heavy petroleum distillate and hydrocracking the treated distillate in the presence of a specified hydrocracking catalyst. CONSTITUTION: A catalyst support obtained by molding, drying and firing a composite gel obtained by mixing or depositing an aluminum oxide hydrate with or on a silica-zirconia hydrogel obtained by depositing zirconium hydroxide on a silica hydrogel is impregnated with metals of groups VI and VII in the periodic table to obtain a hydrocracking catalyst having a mean pore diameter of 5-10nm. A heavy petroleum distillate having a boiling point of 250-600 deg.C is hydrotreated in the presence of a hydrotreatment catalyst to obtain a petroleum distillate having a nitrogen content of 1000mass ppm or below. This distillate is hydrocracked in the presence of the hydrocracking catalyst under conditions including a temperature of 300-500 deg.C, a reaction pressure of 5-20MPa, an LHSV of 0.05-2h<-1> and a hydrogen/oil ratio of 200-1500Nm<3> /m<3> .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for hydrocracking heavy petroleum distillate oil such as vacuum gas oil, and more particularly to high quality by hydrocracking heavy petroleum distillate oil such as vacuum gas oil. Method for obtaining kerosene and light oil.

[0002]

2. Description of the Related Art In recent years, demand for light petroleum products has increased in Japan, whereas crude oil itself tends to become heavier. Therefore, a technology for decomposing heavy petroleum distillate into light distillates. Is becoming more and more important. By the way, sulfur in diesel light oil is not only discharged as sulfur oxides in the exhaust gas of diesel engine to pollute the environment, but also the sulfur content in diesel light oil and diesel engine exhaust gas which is one of the environmental pollutants. Since there is a positive correlation with the amount of particulates in the oil, low sulfur of diesel oil is currently being promoted. The hydrocracked gas oil obtained by hydrocracking heavy petroleum distillate oil has a sulfur content of 0.01 mass% or less, and this sulfur content is obtained by desulfurizing straight-run gas oil. 1-2 from that of straight-run desulfurized oil
It is on the order of magnitude lower. The same applies to kerosene. By hydrocracking heavy petroleum distillate oil, it is possible to obtain high-quality kerosene with a very low sulfur content of 1 mass ppm or less and a high smoke point. . Therefore, also from the viewpoint of environmental protection, there is a strong social need for a hydrocracking method for heavy petroleum distillate as a means for obtaining kerosene or light oil having a very small sulfur content.

Conventionally, various compositions and manufacturing methods of catalysts used for hydrocracking heavy petroleum distillate have been proposed, but basically, hydrogen of a metal component supported on a carrier is proposed. So-called bifunctional catalysts have been used which utilize the oxidization activity and the decomposition activity derived from the property of the carrier as a solid acid. And, as the metal component, a catalyst using nickel or cobalt which is a Group VIII metal of the periodic table and molybdenum or tungsten which is a Group VI metal of the periodic table is the most common, and solid acid In terms of the catalyst carrier that it has, a binary complex oxide represented by silical alumina is most often used. Further, in JP-A-58-210847, a catalyst using a dual-functional catalyst as described above, in which silica or magnesia is added as a second component to alumina-titania as a catalyst carrier, is used. It is described that it is effective for demetalization of oil output, and in JP-A-58-210993, a catalyst is produced by using a ternary complex oxide composed of alumina, titania, and zirconia as a carrier, and a heavy distillate. It is disclosed that it has excellent activity for oil demetallization. Furthermore, JP-A-58-21929
3 gazette discloses a catalyst in which a hydrogenation active metal component is supported on a carrier containing alumina or titania as a main component and containing at least one inorganic oxide selected from silica, titania, zirconia, boria and phosphia, It is described that it is effective for hydrocracking of heavy distillate. However, conventional catalysts including the above-exemplified catalysts do not always reach a sufficiently satisfactory level in terms of hydrocracking activity.

[0004]

An object of the present invention is to increase the production of high-quality kerosene and gas oil from heavy petroleum distillate oil such as vacuum gas oil using a highly active hydrocracking catalyst. .

[0005]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies in order to solve the above-mentioned problems found in the prior art. As a result, the ternary complex oxide obtained by a specific production method is used as a carrier. It was found that the above hydrocracking catalyst has high activity for hydrocracking heavy petroleum distillate under specific reaction conditions, and the present invention was completed. That is, in the hydrocracking method of the present invention, a heavy petroleum distillate having a boiling range of 250 to 600 ° C. is first hydrotreated in the presence of the hydrotreating catalyst (a) to obtain a petroleum distillate. The nitrogen content is reduced to 1000 mass ppm or less, and then, in the presence of the following hydrocracking catalyst (b), the reaction temperature is 300 to 500 ° C., the reaction pressure is 5 to 20 Mp.
a, LHSV 0.05 to 2 h ^-1 , hydrogen / oil ratio 200 to 1
It is characterized in that the hydrocracking is carried out under the condition of 500 Nm ³ / m ³ . Hydrocracking catalyst (b) A silica-zirconia hydrogel obtained by depositing zirconium hydroxide on silica hydrogel, a catalyst carrier obtained from a composite gel obtained by mixing or depositing aluminum oxide hydrate, and a periodic Front
A catalyst having an average pore diameter of 5 to 10 nm, on which at least one Group VI metal and at least one Group VIII metal are supported.

The feed oil used in the hydrocracking method of the present invention has a boiling point of 250 to 600 ° C, preferably 280 to 5 ° C.
It is a heavy petroleum distillate oil in the range of 50 ° C., and preferably vacuum gas oil. As the hydrotreating catalyst (a) used in the present invention, an ordinary catalyst used for hydrodesulfurization and denitrification of petroleum distillate oil can be used, but molybdenum and tungsten are used as stable metal oxide carriers. It is preferable to use a catalyst supporting at least one metal component selected from nickel, cobalt and cobalt. More specifically, a catalyst in which at least one metal selected from nickel and cobalt and at least one metal selected from molybdenum and tungsten is supported on an alumina carrier or a silica alumina carrier is preferable. A catalyst supporting nickel and molybdenum and a catalyst supporting cobalt and molybdenum on an alumina carrier are particularly preferable.
The amount of the metal component supported is in the range of usually 3 to 30% by mass, preferably 5 to 25% by mass, calculated as the total of each metal and calculated as the metal oxide. And when combining Group VI metals and Group VIII metals, the total amount of Group VI metals is preferably 1
10 to 10% by mass, more preferably 3 to 7% by mass,
The total amount of Group VIII metals is preferably 2 to 25% by mass, more preferably 5 to 20% by mass.

The hydrocracking catalyst (b) used in the present invention is
A carrier composed of a ternary complex oxide prepared by a specific method is prepared by supporting at least one metal of Group VI metal and at least one metal of Group VIII metal of the Periodic Table. The ternary complex oxide used for the carrier is prepared as follows. The first step of carrier preparation is a step of adding aqueous ammonia to an aqueous solution of an alkali metal silicate to obtain a silica hydrogel. The pH at the time of gelation is adjusted to 2 to 6, preferably 3.5 to 5. In the next second step, a zirconium salt aqueous solution is added to the silica hydrogel slurry, and a base is added to the acidified slurry to adjust the pH to 6 to 8, preferably around 7, and the silica-zirconia hydrogel slurry is added. Is a step of obtaining. As the zirconium salt, any water-soluble zirconium compound such as nitrate, sulfate and oxychloride can be used. In this step, the zirconia content in the silica-zirconia hydrogel produced is 0.
A range of 1 to 70% by mass, preferably 1 to 30% by mass is selected. The silica-zirconia hydrogel slurry thus obtained is washed, molded, dried and calcined to obtain a binary complex oxide, which has properties as a solid acid, but in terms of pore structure, surface area, etc. It does not usually have the physical properties required as a catalyst carrier. Therefore, in the present invention, a step of adding an alumina component to silica-zirconia hydrogel is adopted as the third step of preparing the carrier. As a method of adding the alumina component, (1) a method of mixing a separately prepared aluminum oxide hydrate (alumina hydrogel) with the above silica-zirconia hydrogel slurry, or (2) the above silica-zirconia hydrogel slurry Alternatively, a method of mixing an aqueous solution of an aluminum salt, neutralizing with a base, and depositing an alumina hydrogel on the silica-zirconia hydrogel can be adopted. As the base used for depositing the alumina hydrogel, sodium aluminate, ammonia, etc. are used. Even if either of the above methods (1) and (2) is adopted,
It was confirmed that the properties of the obtained ternary complex oxide did not differ. The alumina content in the silica-zirconia-alumina hydrogel obtained in the third step is selected in the range of 5 to 70% by mass on the basis of dry oxide, but preferably 10
To 40% by mass, more preferably 20 to 35% by mass. In addition, as a reminder, in the above description, an example of using an alkali metal silicate aqueous solution as the silica source of the carrier was shown, but a silicic acid solution obtained by dealkalizing the alkali metal silicate aqueous solution by an ion exchange method or the like. Can also be used as the silica source. The silica-zirconia-alumina hydrogel slurry thus obtained is then filtered and washed to remove impurities such as sulfate ions, sodium ions and halogen ions. Then, the cake after washing is sufficiently kneaded, and the carrier is prepared through the steps of molding, drying and firing. Drying is performed under the condition of 100 to 250 ° C. for 0.5 to 24
Conduct within a time range. The firing is carried out at a temperature in the range of 300 to 700 ° C. for 0.5 to 10 hours. The hydrocracking catalyst (b) used in the present invention comprises at least one metal component selected from Group VI metals of the Periodic Table and at least one selected from Group VIII metals of the Periodic Table on the above carrier. The metal component of is supported. As a method for supporting these metal components, known methods such as an impregnation method, an immersion method, and a kneading method can be used. Preferred Group VI metals are molybdenum and tungsten, and
Examples of Group VIII metals include nickel and cobalt. The supported amount of each metal component is preferably in the range of 3 to 30 mass% in terms of metal oxide, and 5 to 25 mass%.
Is more preferable. The average pore diameter of the hydrocracking catalyst (b) used in the present invention is 5 to 10 nm, preferably 6 to 9 nm.

In carrying out the method of the present invention, the hydrotreating catalyst and the hydrocracking catalyst may be charged in the same reactor or may be charged in different reactors. In the former case, the hydrotreating catalyst (a) is charged in the preceding stage in the reactor,
The hydrocracking catalyst (b) is filled in the latter stage. In the latter case, the upstream reactor is charged with the hydrotreating catalyst (a),
The reactor on the downstream side is charged with the hydrocracking catalyst (b). In any case, the ratio of the hydrotreating catalyst (a) to the hydrocracking catalyst (b) is preferably 1:10 to 3: 1 on a volume basis, and more preferably 1: 5 to 1: 1. The reaction system is preferably a fixed bed flow system. The hydrotreating catalyst (a) and hydrocracking catalyst (b) used in the present invention are
Preferably, it is sulfurized before the reaction. This sulfurization treatment can be carried out by a known method, and examples of the sulfurizing agent used therein include hydrogen sulfide, carbon disulfide, dimethyl disulfide and the like.

According to the method of the present invention, a heavy petroleum fraction having a boiling point range of 250 to 600 ° C., which is a feed oil, is first hydrotreated and then hydrocracked. This is because if the sulfur compounds and nitrogen compounds in the feed oil are hydrogenated and removed, the high catalytic activity of the hydrocracking catalyst (b) at the latter stage can be sufficiently extracted. Therefore, in the first-stage hydrotreatment, the nitrogen content in the feedstock oil is reduced to 1000 mass ppm or less, preferably 400 mass ppm or less, and more preferably 200 mass ppm or less. The reaction conditions of the hydrotreating step are, for example, a reaction temperature of 300 to 500.
C, reaction pressure 5 to 20 MPa, LHSV (liquid space velocity)
0.05 to 2 h ^-1 , hydrogen / oil ratio 200 to 1500 Nm ³
The range of / m ³ is preferable. Regarding the reaction conditions of the hydrocracking step, the reaction temperature is 300 to 500 ° C, preferably 340 to 450 ° C, more preferably 350 to 500 ° C.
Hold at 430 ° C. The reaction pressure is 5 to 20 MPa, preferably 7 to 15 MPa, more preferably 8 to 13 M.
It is in the range of Pa. LHSV is 0.05 to 2 h ^-1 , preferably 0.1 to ¹ h ^-1 , more preferably 0.2 to 0.
It is in the range of 5 h ^-1 . The hydrogen / oil ratio is 200 to 1
500 Nm ³ / m ³ , preferably 300 to 1200 Nm ³
/ M ³ , more preferably in the range of 400 to 800 Nm ³ / m ³ . The reaction temperature in the reaction conditions of the hydrocracking step is the average temperature in the reactor, the reaction pressure is the total pressure in the reactor, and the LHSV is the total amount of the hydrotreating catalyst and the hydrocracking catalyst. Means a value.

[0010]

EXAMPLES Examples and comparative examples will be described below. Catalyst Preparation Example 1 A silica-zirconia hydrogel slurry was obtained by adding a zirconium sulfate aqueous solution to a silica hydrogel slurry that had been gelled at pH 4 and aged at pH 7 for 2 hours, and adjusting the pH of the slurry to 7. .
After aging this for 30 minutes, an aqueous solution of aluminum sulfate was added, and ammonia water was added to the slurry to adjust the pH of the system to 7 to obtain a silica-zirconia-alumina hydrogel slurry. The obtained slurry was filtered and washed, and then extrusion-molded to have a diameter of 1/16 inch. The molded product was further dried and calcined to obtain a catalyst carrier. The composition of the carrier was silica 56% by mass, zirconia 14% by mass, and alumina 30% by mass in terms of oxide. The obtained carrier was loaded with 10% by mass of nickel and 20% by mass of tungsten in terms of oxide, and the average pore diameter was 8.0 nm.
Catalyst A was obtained. Catalyst Preparation Example 2 An aqueous zirconium sulfate solution was added to a silica hydrogel slurry obtained by gelling an aqueous sodium silicate solution at 60 ° C. and pH 4 and then raising the pH to 7 and aging at 60 ° C. for 2 hours. A silica-zirconia hydrogel slurry was prepared by adjusting the pH of the slurry to 7. On the other hand, a sodium aluminate solution and an aluminum sulfate aqueous solution were mixed at 60 ° C. and pH 7 to prepare an alumina hydrogel slurry. Next, the silica-zirconia hydrogel slurry and the alumina hydrogel slurry were mixed and aged for 20 minutes while keeping the pH of the solution at 7 and then the slurry was filtered and washed to have a diameter of 1/16 inch. Extruded and molded. The molded product was further dried and fired to obtain a silica-zirconia-alumina carrier. The composition of the carrier was silica 56% by mass, zirconia 14% by mass, and alumina 30% by mass in terms of oxide. The obtained carrier was loaded with 10% by mass of nickel and 20% by mass of tungsten in terms of oxide, and the average pore diameter was 7.5 nm.
Catalyst B was obtained. Catalyst Preparation Example 3 An aqueous solution of aluminum sulfate was added to a silica hydroslurry obtained by gelling an aqueous solution of sodium silicate and aging at pH 7 for 2 hours, and further an aqueous solution of sodium aluminate was added to obtain a silica-alumina hydrogel slurry. The slurry was filtered and washed, and then extrusion-molded to have a diameter of 1/16 inch. The molded product was further dried and fired to obtain a silica-alumina carrier. The composition of this carrier was 70% by mass of silica and 30% by mass of alumina in terms of oxide.
The obtained carrier was loaded with 10% by mass of nickel and 20% by mass of tungsten in terms of oxide, and the average pore diameter was 7.2 n.
m catalyst C was obtained.

Example 1 A hydrotreating catalyst (5% by mass of nickel in terms of oxide on an alumina carrier, molybdenum, molybdenum) was added to a reactor at the front stage of a fixed bed flow reactor equipped with two reactors connected in series. 2
0% by mass) was loaded into the reactor, and the catalyst A obtained in Catalyst Preparation Example 1 was loaded into the subsequent reactor, and the hydrocracking activity of the catalyst A was evaluated. The hydrotreating catalyst and the hydrocracking catalyst were used in a volume ratio of 1: 2. Further, prior to the reaction, the catalyst was subjected to sulfurating treatment with a solution of carbon disulfide in paraffin. Table 1 shows the properties of the vacuum gas oil used as the feedstock, and Table 2 shows the reaction conditions. In addition, the nitrogen content of the reduced pressure gas oil supplied from the former reactor to the latter reactor was 180 mass ppm.

[Table 1] Raw material oil density (15 ° C.) g / cm ² 0.93 Sulfur content Mass% 2.0 Nitrogen content Mass ppm 1200 Aniline point ℃ 85 Boiling point ℃ 273 to 584

[Table 2] Reaction conditions Reaction temperature ℃ 400 Reaction pressure MPa 12 LHSV h ^-1 0.4 Hydrogen / oil ratio Nm ³ / m 590 Note) LHSV is a value relative to the total amount of the hydrotreating catalyst and the hydrocracking catalyst. Table 3 shows the results of evaluating the hydrocracking activity of catalyst A. Example 2 The hydrocracking activity of catalyst B was evaluated in the same manner as in example 1 except that catalyst B obtained in catalyst preparation example 2 was used instead of catalyst A. The results are shown in Table 3. Comparative Example 1 The hydrocracking activity of the catalyst C was evaluated in the same manner as in Example 1 except that the catalyst C obtained in Catalyst Preparation Example 3 was used instead of the catalyst A. The results are shown in Table 3.

[Table 3] Activity of each catalyst and yield of kerosene and light oil (relative value) Catalyst Relative activity ¹⁾ Kerosene yield ²⁾ Light oil yield ³⁾ Example 1 A 120 121 124 Example 2 B 125 126 122 122 Comparative example 1 C 100 100 100 Note 1) Relative rate constant of each catalyst when the rate constant of catalyst C is 100. 2) Relative value of kerosene yield when the kerosene yield of catalyst C is 100. 3) Relative value of light oil yield when the light oil yield of catalyst C is 100. Comparative Example 2 Without using the reactor of the first stage filled with the hydrotreating catalyst, the reactor of the latter stage (the filling amount of the catalyst A is the same as that of Example 1)
Was used to hydrocrack the vacuum gas oil shown in Table 1 under the conditions shown in Table 2, and the activity of catalyst A was evaluated. Table 4 shows the results
Shown in Comparative Example 3 The reduced pressure gas oil was hydrocracked in the same manner as in Comparative Example 2 except that the catalyst B was used in place of the catalyst A, and the activity of the catalyst B was evaluated. The results are shown in Table 4. Comparative Example 4 The reduced pressure gas oil was hydrocracked in the same manner as in Comparative Example 2 except that the catalyst C was used in place of the catalyst A, and the activity of the catalyst C was evaluated. The results are shown in Table 4.

[Table 4] Activity of each catalyst and yield of kerosene and light oil (relative value) Catalyst relative activity ¹⁾ Kerosene yield ²⁾ Light oil yield ³⁾ Comparative example 2 A 97 96 97 97 Comparative example 3 B 99 98 96 96 Comparative example 4 C 100 100 100 Note 1) Relative rate constant of each catalyst when the rate constant of catalyst C is 100. 2) Relative value of kerosene yield when the kerosene yield of catalyst C is 100. 3) Relative value of light oil yield when the light oil yield of catalyst C is 100.

[0012]

According to the method of the present invention in which a hydrotreating process for desulfurizing and denitrifying a feedstock and a catalyst comprising a specific ternary complex oxide and an active metal component are combined, a heavy oil such as vacuum gas oil can be obtained. High quality kerosene and gas oil can be produced in high yield from various petroleum distillates.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ken Ushio 8 Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa Nippon Petroleum Co., Ltd. Central Research Laboratory

Claims (1)

[Claims] 1. A heavy petroleum distillate having a boiling range of 250 to 600 ° C. is first hydrotreated in the presence of a hydrotreating catalyst (a) so that the petroleum distillate has a nitrogen content of 1000. Mass ppm or less, and then in the presence of the following hydrocracking catalyst (b), reaction temperature 300 to 500 ° C., reaction pressure 5 to 20 MPa, LHSV 0.05 to 2 h ⁻¹ , hydrogen / oil ratio 200 to 1500 Nm ³ A method for hydrocracking petroleum distillate oil, characterized in that hydrocracking is carried out under the condition of / m ³ . Hydrolysis catalyst (b) Silica-zirconia hydrogel obtained by depositing zirconium hydroxide on silica hydrogel is mixed with or deposited on aluminum oxide hydrate to obtain a composite gel, which is then molded, dried and fired. The catalyst carrier produced contains at least one metal of Group VI of the periodic table,
A catalyst having an average pore diameter of 5 to 10 nm, produced by supporting at least one metal of Group VIII metal.