JP2003277772A - Method of two-stage hydrotreating of heavy hydrocarbon oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrotreating method which comprises subjecting a heavy hydrocarbon oil containing a large quantity of impurities comprising e.g. sulfur, residual carbon, a metal, nitrogen and an asphaltene, particularly a heavy oil containing a large quantity of heavy vacuum residual oil to hydrotreating to a high degree while removing it appropriately and which is excellent in reducing or controlling the amount of a sediment formed. <P>SOLUTION: This method of hydrotreating of a heavy hydrocarbon oil comprises: bringing a heavy hydrocarbon oil into contact with a catalyst (1) having a specified specific surface area and pore distribution in the presence of hydrogen in a first reactor filled with the catalyst (1) to effect first-stage hydrotreating; and bringing the hydrotreated oil obtained in the first stage into contact with catalysts (2a) and (2b) each having a specified specific surface area and pore distribution in the presence of hydrogen in a second reactor filled with the catalysts (2a) and (2b) to effect second-stage hydrotreating. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for hydrotreating a heavy hydrocarbon oil, and more particularly to a catalyst combination which exhibits high performance in hydrotreating a vacuum residue oil which is a heavy fraction among hydrocarbon oils. Regarding the method. More specifically, in the hydrotreating of heavy hydrocarbon oils containing large amounts of impurities (impurities) such as sulfur, metals, and asphaltene, by using catalysts with different functions in combination, the desired hydrodesulfurization can be achieved. (HDS), hydrodemetallization (HDM) and hydrodeasphaltene removal (asphaltene removal), and a method for hydrotreating that can suppress the formation of sediments that are deposited on a heat exchanger during the operation of the apparatus and become an obstacle to the operation. .

[0002]

2. Description of the Related Art Atmospheric residue (AR) containing 50% by weight or more of a component having a boiling point of 538 ° C. or higher, or a vacuum residue (Vacuum Residue; VR) is called heavy hydrocarbon oil. It is strongly demanded that such a heavy hydrocarbon oil be hydrotreated to remove impurities such as sulfur and be converted into a light oil having a high added value for use. The light oil produced by the cracking of such a heavy distillate has a higher sulfur concentration than the corresponding straight distillate, and therefore requires desulfurization and hydrotreating again.

Contaminants to be removed by hydrogenation / cracking treatment include sulfur and residual carbon (Conradson Ca
Rbon Residue (CCR), various metals, nitrogen, asphaltene, etc., but nowadays, such contaminants can be highly removed by improving catalysts and the like. However, since asphaltene is an aggregate of condensed aromatic compounds and dissolves in a well-balanced manner with the surrounding solvent components, when asphaltene is decomposed excessively, it aggregates into particulate matter (sludge) and sediment (sludge). A sediment) is generated.

The details of the sediment are Shell.
Precipitates measured by testing samples with the Hot Filteration Solid Test (SHFST) (Van Kerknoort
Et al., J. Inst. Pet. 37 p.596-604 (1951)),
The usual content is said to be about 0.19 to 1% by weight in the product having a boiling point of 340 ° C. or higher, which is recovered from the flash drum bottom liquid in the refining process.

Since the sediment is deposited and deposited in a device such as a heat exchanger or a reactor during oil refining, there is a possibility that the flow path will be blocked and the operation of the device will be seriously hindered. In particular, in the hydrotreatment of a heavier hydrocarbon oil containing a large amount of vacuum residue oil, the production of sediment becomes remarkable due to the large amount of asphaltene. For this reason, it is a new subject in the improvement of the hydrotreating catalyst to achieve a high degree of hydrotreating and at the same time minimize the formation of sediment.

On the other hand, the light oil produced by the cracking of the heavy distillate has a higher sulfur concentration than the corresponding straight distillate,
Desulfurization and hydrotreatment are required again. Therefore, in order to produce low-sulfur light oil, it is necessary to suppress the formation of sediment during hydrogenation / cracking of heavy fractions and to perform stable operation, and to use a catalyst or a combination of catalysts with high desulfurization performance for cracked light fractions. It is said that

The present inventors used a combination of catalysts having different functions in the first stage and the second stage in the two-stage hydrotreatment, and further used a catalyst having a specific catalyst composition and pore size distribution in the second stage. It has been found that the mixed use of different types of catalysts is more effective in suppressing the formation of sediment than the case where each catalyst is used alone, and exhibits a high desulfurization performance for light fractions. That is,
The use of three different catalysts having a specific pore size in combination (one in the first stage and two in the second stage) will interfere with the operation of vacuum residue oil containing heavy fractions. We have found a method that can produce highly desulfurized white oil products with high economic value added in high yield while suppressing the formation of sediments as much as possible.

More specifically, the present invention reduces asphaltene, which causes sediment, as much as possible by a catalyst for asphaltene decomposition and high demetallization in the first stage of hydrotreating, and then in the second stage ( By disposing a catalyst exhibiting high desulfurization performance in the final stage), it is possible to carry out an operation with less generation of sediment while obtaining a desired desulfurized product oil. Especially in the second stage, since it is necessary to carry out a high degree of desulfurization while suppressing the formation of sediment, it has been difficult to use two kinds of catalysts having a specific catalyst composition and pore size distribution in a mixed manner. Suppression and maintenance of sediment and high desulfurization / hydrogenation are achieved.

On the other hand, in the prior art, both suppression and maintenance of sedimentation and high hydrodesulfurization have not been sufficiently achieved as described below. Japanese Examined Patent Publication No. 7-65055 discloses a hydrotreating method for converting heavy components of hydrocarbon oil containing sulfur impurities and metallic impurities in at least two stages. In this publication, 0.1 to 5% by weight of a metal oxide catalyst is used for the purpose of hydrodemetallization in the first step, and 7 to 30 as the same metal oxide is used for the purpose of hydrodesulfurization in the subsequent second step. A method of hydrotreating with a metal oxide catalyst in a weight percentage has been proposed. According to this method, it is said that the demetalization and hydrocracking are preferably carried out in the first step, and the desulfurization is carefully carried out in the second step to treat the residue. In particular, the combination of alumina-aggregated catalysts having a "urchin-like" structure shows remarkable results.

However, according to the technique, although the demetallizing function required in the first step is improved, the desulfurization and hydrogenation functions are deteriorated because the catalyst loading amount of the catalyst used in the first step is low, Therefore, a high desulfurization function is required in the second stage, and a catalyst with a large amount of supported catalyst is inevitably required. Further, in the case where a high degree of desulfurization is performed in the second stage, the catalyst generates a large amount of heat, but at this time, asphaltene content is aggregated as the decomposition rate advances. As far as the examples of the invention are concerned, asphaltene agglomeration is not sufficiently prevented, and as a result, there is a possibility that the operation of the apparatus may be hindered.

JP-A-8-325580 discloses a complete catalytic hydroconversion method for heavy petroleum feedstock.
In the method, in the first step, a carrier material selected from alumina / silica and a combination thereof is added with an active metal oxide selected from cadmium, chromium, cobalt, iron, molybdenum, nickel, tin, tungsten and a combination thereof. A catalyst supporting a total of 2 to 25% by weight was supplied, the reaction temperature was 438 to 468 ° C, and the hydrogen partial pressure was 105 to 24.
The reaction is carried out under the reaction conditions of 5 kg / cm ² and space velocity of 0.3 to 1.0 (Vf / hr / Vr), and then the same catalyst is supplied in the second stage, the reaction temperature is 371 to 427 ° C., the hydrogen partial pressure is 105-24
A method for hydroconversion under the reaction conditions of 5 kg / cm ² and space velocity 0.1 to 0.8 (Vf / hr / Vr) is described. This method is a catalytic hydroconversion method of "H-Oil (registered trademark)", which is a heavy petroleum raw material, and proposes a solution to the treatment of unreacted residues by recycling them.

Also, in order to achieve a more complete hydroconversion of the feedstock and effective use of the catalyst, the first stage reactor is provided with a higher reaction temperature and a lower catalytic activity, while the second stage reaction is carried out. By providing the reactor with a lower reaction temperature and a higher catalytic activity, it is said that the reactor is provided with the improved harmonization of the reaction conditions and the catalytic activity required for the reactor in each stage.

However, the high temperature reaction of the first stage disclosed in this publication accelerates the thermal condensation of asphaltene,
On the other hand, it becomes impossible to stabilize fragments such as resinous substances that are generated by the thermal decomposition of oil, which may cause rapid coke deterioration of the catalyst in the second stage.

Further, in this method, since a catalyst suitable for preventing the asphaltene aggregation and sedimentation caused by the second step is not used,
In this respect, there is a possibility that it may be an obstacle when the device is operated.

Japanese Examined Patent Publication No. 6-53875 describes a multi-step contact method for high conversion of heavy hydrocarbon liquid feedstock. In the first stage, a fixed bed or boiling bed reactor,
The reaction temperature is 415 to 455 ° C. and the hydrogen partial pressure is 70 to 211.
kg / cm ² , space velocity is 0.2 to 2.0, the second stage is a boiling bed reactor, the reaction temperature is 415 to 455 ° C., the hydrogen partial pressure is 70 to 211 kg / cm ² , and the space velocity is 0. A multi-stage catalytic hydrotreating method of .2-2.0 is described. The catalyst that can be used contains an active metal oxide selected from cadmium, chromium, cobalt, iron, molybdenum, nickel, tin, tungsten and mixtures thereof in a carrier material selected from the group consisting of alumina, silica and combinations thereof. It is a catalyst that does. In this method, the vacuum bottoms are recirculated in order to achieve a high decomposition rate to achieve a high decomposition rate, but no preventive measures against asphaltene agglomeration, which hinders operation at a high decomposition rate, are shown, It becomes a problem when driving.

Regarding the catalyst to be used, the description on the catalyst means that for the promotion of the hydrogen conversion reaction, or in the case of a feedstock having a high metal content, a demetallization type catalyst is used in the first stage reaction. There is no disclosure of the actual catalyst, only the content. Further, regarding the disclosure of the catalyst, since this publication is insufficient, it cannot be judged that an effective result can be expected with respect to precipitation of sediments which may interfere with the operation. Therefore, in the catalyst combination according to the above-mentioned prior art, the effect of suppressing the formation of sediment, which is an operation constraint of the apparatus, is sufficiently achieved while achieving a high degree of desulfurization and cracking in the hydrocracking of heavy hydrocarbon oil. Not not.

[0017]

DISCLOSURE OF THE INVENTION The present invention provides a heavy hydrocarbon oil containing a large amount of impurities such as sulfur, residual carbon, metals, nitrogen and asphaltene, particularly 80% of a vacuum residue fraction.
Combining catalysts that take into consideration the function so that heavy oil including the above can be highly hydrotreated and appropriately removed, and in the second stage, two different catalysts having a specific pore size distribution and catalyst composition should be mixed. It is an object of the present invention to provide a more effective hydrotreating method. In particular, a catalyst combination which has not been sufficiently solved by the above-mentioned prior art, shows high performance in high-grade decomposition and removal of asphaltene, and reduction in the sedimentation that accompanies an increase in the conversion rate, and can enhance desulfurization performance. The purpose is to provide.

[0018]

The inventors of the present invention have conducted extensive studies in view of the above problems, and as a result, in the catalytic two-step hydroconversion method, a catalyst having a specific pore size distribution in the first step was selected. To reduce impurities in heavy hydrocarbon oil, especially to effectively achieve deasphaltenization which is effective for demetalization and prevention of asphaltene coagulation, and then in the second stage a specific pore size distribution different from the first stage , It was found that the use of a mixture of two types of catalysts having a catalyst composition can improve the relationship between hydrogenation and sedimentation, which has been a problem up to now, and while achieving particularly high desulfurization and hydrogenation reactions, The present invention has been completed by finding a method for catalytic hydrotreatment of heavy oil that can suppress the formation of sediment due to agglomeration of asphaltene and perform stable operation.

That is, a catalyst having a specific pore size distribution is used in the first stage, and in the subsequent second stage, two kinds of catalysts having different functions having a unique pore size distribution and catalyst composition different from those in the first stage are prepared. The inventors have found that the mixed use allows a stable operation in which the production of sediment is suppressed but the desulfurization and hydrogenation proceed to a high degree by the synergistic effect. According to the present invention, the effect is particularly great for the hydrotreatment of heavy hydrocarbon oils.

More specifically, in a two-stage hydrotreating method, a catalyst having a specific pore size distribution in the reactor of the first stage is supplied to promote the decomposition of asphaltene which promotes the formation of sediment. While carrying out a suitable hydrogenation reaction, in the subsequent second stage reactor,
Pore size distribution to improve desulfurization performance, catalyst of catalyst composition,
By supplying a catalyst having a pore size distribution and a catalyst composition that causes an appropriate asphaltene decomposition, a method is provided in which a high degree of desulfurization is achieved and sediment is not generated as much as possible. Further, by removing asphaltene to a high degree in the first stage, it is possible to suppress the generation of undesired coke deposited on the catalyst in the thermal decomposition in the second stage and prevent the deterioration of the catalyst performance.

In short, in the hydrotreating method of the present invention, the heavy hydrocarbon oil is brought into contact with the catalyst (1) in the presence of hydrogen in the first reactor filled with the following catalyst (1), Stage hydrotreatment, and then the hydrotreated oil obtained in the first stage was mixed with the following catalyst (2a) and catalyst (2b) in a second reaction apparatus filled with the catalyst in the presence of hydrogen. (2a) and the catalyst (2b) are brought into contact with each other to carry out the second stage hydrotreatment, which is a hydrotreatment method for heavy hydrocarbon oils.

The catalyst (1) is composed of a porous alumina carrier and an oxide of a Group 6A metal in the periodic table based on the catalyst weight.
-20% by weight, 0.5% of Group 8 metal oxide in the periodic table
6% by weight is supported, and the (a) specific surface area of the catalyst is 100 to 1
80 m ² / g, (b) the total pore volume is 0.55 ml / g or more, and the pore distribution diameter of the catalyst is (c1) the proportion of the pore volume of 200 Å or more based on the total pore volume. 5 of total pore volume
0% or more, (c2) diameter is 2,000 Å or more, the proportion of pore volume is 10 to 30% of the total pore volume, (c3) diameter is 10,000
This is a hydrotreating catalyst in which the proportion of the pore volume of 0Å or more is 0 to 1% of the total pore volume.

The catalyst (2a) contains, on the basis of the catalyst weight, a metal oxide of Group 6A in the periodic table of 7 to 7 based on the catalyst weight.
20% by weight, 0.5 to 6 of oxide of Group 8 metal of the periodic table
The catalyst is supported in an amount of wt%, and the (a) specific surface area of the catalyst is 100 to
180 m ² / g, (b) the total pore volume is 0.55 ml / g or more, and the catalyst pore distribution diameter is based on the total pore volume (d1) the ratio of the volume of 100 to 1,200Å Is over 85%,
(d2) The ratio of the volume of pores having a diameter of 4,000 Å or more is 0
Hydrogen having a proportion of 2%, (d3) pores having a diameter of 10,000 Å or more and a volume ratio of 0 to 1%, and (d4) having a proportion of pores having a diameter of 200 Å or more of 50% or more of the total pore volume. It is a chemical treatment catalyst.

The catalyst (2b) comprises a heat-resistant inorganic porous carrier on which at least one hydrogenation active component is supported, and the catalyst (a)
Specific surface area of 150 m ² / g or more, (b) total pore volume of 0.55
ml / g or more, and the pore distribution diameter of the catalyst is (d1) based on the total pore volume (d1), and the ratio of the pore volume with a diameter of 100 to 1,200Å is 75% or more of the total pore volume, (d2) Diameter is 4,000
Å volume ratio is 0-2%, (d3) diameter is 10,000
The ratio of the pore volume of 0Å or more is 0 to 1% of the total pore volume, (d
4) A hydrotreating catalyst in which the proportion of the volume of pores having a diameter of 200Å or more is less than 50% of the total volume of pores.

Further, the present invention is characterized in that the heat-resistant inorganic porous carrier of the catalyst (2b) is a silica-alumina carrier containing 3.5% by weight or more of silica. Also,
In the present invention, the catalyst (2b) contains silica-alumina support containing 3.5 wt% or more of silica in an amount of 7 to 20 wt% of a Group 6A metal oxide of the periodic table based on the weight of the catalyst.
A catalyst for hydrotreating, wherein the oxide of a Group 8 metal of the periodic table is supported in an amount of 0.5 to 6% by weight, and the oxide of a Group 1A metal of the periodic table is supported in an amount of 0.1 to 1% by weight. It is characterized by being.

Further, according to the present invention, the catalyst (2b) is a silica-alumina carrier containing a silica amount of 3.5% by weight or more, and an oxide of a Group 6A metal of the periodic table is 7 to 20 based on the catalyst weight. % By weight, 0.5 to 6% by weight of oxide of Group 8 metal of the periodic table, and 0.5 of oxide of Group 1A metal of the periodic table.
1 to 1% by weight, 0.1% of Group 5B element oxide in the periodic table
The hydrotreating catalyst is supported in an amount of ˜2% by weight.

Further, the present invention is characterized in that the heavy hydrocarbon oil is a heavy oil containing 80% by weight or more of a vacuum residue fraction, and in the first stage and the second stage, the temperature is from 350 to 45.
It is characterized in that the hydrogenation treatment is performed under conditions of 0 ° C. and a pressure of 5 to 25 MPa.

Further, the mixture ratio of the catalyst (2b) in the catalyst packed in the second stage reactor is 1% by weight or more, and the heavy hydrocarbon oil is further hydrogenated in the form of a boiling bed. It is characterized by being brought into contact with a treated catalyst.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION [I] Catalyst The hydrotreating catalyst (catalyst (1)) used in the first stage of the hydrotreating method of the present invention, and the hydrotreating used in the second stage. Catalyst (catalyst (2a) and catalyst (2
b)) is composed of a catalyst substance, which is a metal oxide having hydrogenation activity, and a carrier carrying the catalyst substance.

The components used in the catalyst substance in the present invention are the periodic table (for example, "Iwanami Physics and Chemistry Dictionary 4th Edition", Iwanami Shoten (1) for the catalyst (1) and the catalyst (2a).
Published in 987) in return, "II Periodic Table of Elements"
(a) long-period type ”), which is a composition comprising two components of an oxide of a Group 6A metal and a Group 8 metal.

The catalyst (2b) carries at least one hydrogenation-active component, and examples of such components include Group 1A metals (lithium, sodium, etc.) and 2A of the periodic table.
Group metals (magnesium, calcium, etc.), Group 6A metals (chromium, molybdenum, tungsten, etc.), Group 8 metals (iron, cobalt, nickel, platinum, palladium, etc.), Group 4B elements (tin, lead, etc.), Examples include Group 5B elements (phosphorus, arsenic, antimony, etc.).

The hydrogenation active component supported on the catalyst (2b) is a metal of Group 6A, a metal of Group 8 and a metal of Group 1A in the above periodic table.
A composition consisting of three components of a group metal is preferable, and a composition consisting of four components of an oxide of a Group 6A metal, a Group 8 metal, a Group 1A metal and a Group 5B element of the above periodic table is particularly preferable. In addition, the above-mentioned 1A group, 2A group, 4B group, 5B
Group 6, Group 6A, and Group 8 are Group 1 and Group 2 of Group 18 long-period periodic table (IUPAC system), which are not divided into A and B subgroups.
It corresponds to the 14th group, the 15th group, the 6th group, and the 8th to 10th groups, respectively.

The Group 8 metal used in the catalyst of the present invention is
At least one selected from iron, cobalt, and nickel is preferable, and cobalt and nickel are preferable from the viewpoint of performance and economy, and nickel is particularly preferable. The Group 6A metal is at least one selected from chromium, molybdenum, and tungsten, and molybdenum is preferable from the viewpoint of performance and economy.

As a preferred embodiment of the catalyst (2b),
When the carrier is a silica-alumina carrier containing silica, examples of the Group 1A metal used in addition to the Group 6A metal and the Group 8 metal include lithium, sodium, potassium and the like. From the point of view, sodium is preferable.

Further, as a particularly preferred embodiment of the catalyst (2b), the Group 5A element to be further supported in addition to the Group 6A metal, the Group 8 metal and the Group 1A metal is phosphorus, arsenic, antimony or bismuth. At least one selected,
Phosphorus is preferable in terms of performance.

As described above, in the hydrotreatment of heavy hydrocarbon oils, the production of sediment tends to increase as the hydrogenation increases, but in the present invention, in the second step, a specific pore structure and activity are specified. By mixing a part of the catalyst having the components, it is possible to achieve a higher degree of hydrogenation and suppression of the formation of sediment in a well-balanced manner.

Based on catalyst weight after completion (100% by weight)
The amount of each metal oxide supported in the above case is as follows. That is, the oxide of the Group 6A metal commonly supported by the catalyst (1), the catalyst (2a), and the catalyst (2b) is 7 to 20% by weight, and preferably 8 to 16% by weight. When the amount of such metal oxide is less than 7% by weight, the catalyst performance is insufficiently expressed, while when it exceeds 20% by weight, there is no increase in the catalyst performance.

Further, the Group 8 metal oxide commonly supported by the catalyst (1), the catalyst (2a) and the catalyst (2b) was 0.1.
It is 5 to 6% by weight, preferably 1 to 5% by weight. 0.5
If it is less than 6% by weight, the catalyst performance is insufficiently expressed, while if it exceeds 6% by weight, there is no increase in the catalyst performance.

Further, the Group 1A metal oxide is a catalyst (2
The amount when supported on b) is 0.1 to 1% by weight, preferably 0.1 to 0.5% by weight. If it is less than 0.1% by weight, it is not sufficient to control the surface activity, and the production of sediment is increased, which is not preferable. If it exceeds 1% by weight, the catalyst performance will be insufficiently exhibited.

Further, the Group 5B element oxide is a catalyst (2b).
In the case of being supported on the substrate, the amount is 0.1 to 2% by weight, preferably 0.1 to 1.0% by weight. If it exceeds 2% by weight, hydrogenation other than asphaltene will proceed too much, resulting in a rapid increase in sedimentation. On the other hand, if it is less than 0.1% by weight, efficient hydrogenation cannot be achieved.

Next, the carrier constituting the catalyst will be described. The carrier of the catalyst (1) and the catalyst (2a) is a porous alumina that can be obtained by an industrially produced method, and by representatively coprecipitating sodium aluminate (sodium aluminate) and aluminum sulfate. What is obtained can be used. The gel (pseudo-boehmite) obtained at this time is dried, molded and fired to obtain an alumina carrier.

On the other hand, examples of the heat-resistant inorganic porous carrier used as a carrier for the catalyst (2b) include alumina, silica, silica-alumina, magnesia, zinc oxide, titania, zirconia, zeolite, clay minerals and their composite oxides. However, from the viewpoint of economy and performance, silica-
Alumina is preferred. When the carrier of the catalyst (2b) is a silica-alumina carrier, water glass (sodium silicate) can be used as a silica source to co-precipitate at the same time as the precipitation of alumina, or at the time of immersion in the next step. It is also possible to immerse a solution of a water-soluble silica source.

The specific method for producing the carrier is as follows. First, an alkaline solution such as sodium aluminate, ammonium hydroxide or sodium hydroxide is put into a tank storing tap water or warm water, and then an acidic aluminum solution such as aluminum sulfate or aluminum nitrate is used for mixing. When the catalyst (2b) is a silica-alumina carrier, a tank in which water glass is previously stored may be used as a silica source.

The hydrogen ion concentration (pH) in the mixed solution changes as the reaction proceeds, but the pH at the end of the addition of the acidic aluminum solution is 7 to 9, and the temperature at the time of mixing is the first stage catalyst (1 It is preferable that the temperature is 70 to 85 ° C. for the second stage catalyst, and the temperature is 60 to 75 ° C. for the second stage catalyst (2a) and the catalyst (2b). In order to obtain pores of an appropriate size, the holding time is preferably about 0.5 to 1.5 hours, especially 40 minutes to 80 hours.
Minutes are preferred. A desired alumina hydrate or silica-alumina gel can be obtained by appropriately adjusting various conditions of such addition and mixing.

Next, after separating the obtained alumina hydrate or silica-alumina gel from the solution, a washing method which is widely used in industry, for example, tap water or warm water is applied to perform the washing treatment. Remove the impurities in it. Next, after improving the moldability of the gel using a kneader, the gel is molded into a desired shape by a molding machine. Before loading the catalytically active component, it is preferable to shape it into a desired shape, and the diameter is 0.9.
Cylindrical particles of ˜1 mm, for example 0.95 mm and a length of 2.5-10 mm, for example 3.5 mm, are suitable.

Finally, the formed alumina gel or silica-alumina gel is dried and calcined. The drying condition is a temperature of room temperature to 200 ° C. in the presence of air, and the baking condition is a temperature condition of 300 to 950 ° C., preferably 600 to 900 ° C. in the presence of air, and is performed for about 30 minutes to 2 hours. It is also possible to control the growth of alumina particles and silica-alumina crystals by introducing water vapor during the firing treatment.

By the above-mentioned production method, an alumina carrier or a silica-alumina carrier having properties that substantially match the specific surface area and pore distribution of the finished catalyst described later can be obtained. In the kneading and molding step described above, an acid as a molding aid, for example, nitric acid, acetic acid, formic acid is added, or water is added to adjust the amount of water in the alumina gel and silica-alumina gel. The pore size distribution can be adjusted as appropriate.

Since the specific surface area of the carrier before supporting the metal component of the catalyst substance brings the specific surface area and the pore distribution in a specific range in the completed catalyst, the alumina carrier of the catalyst (1) has a specific surface area of 100 to 200 m ^2. / G, especially 130-170 m ² / g
Is preferred, and the total pore volume is preferably 0.5 to 1.2 ml / g, particularly preferably 0.7 to 1.1 ml / g. On the other hand, catalyst (2a)
The specific surface area of the alumina carrier of No. ² and the silica-alumina carrier of catalyst (2b) is 180 to 300 m ² / in order to bring the specific surface area and the pore distribution of a specific range in the completed catalyst.
g, especially 185 to 250 m ² / g, and the total pore volume of 0.5 to 1.0 ml / g, particularly 0.6 to 0.9 ml / g.

When the heat-resistant inorganic porous simple substance of the catalyst (2b) is a silica-alumina carrier, the silica content is 3.5 based on the completed catalyst including the catalyst substance (100% by weight). % By weight or more, preferably 4.5 to 10
% By weight. If it is less than 3.5% by weight, the catalyst performance is not sufficiently exhibited.

The catalyst of the present invention is manufactured and completed by the method described below. The various metal components for the above-mentioned catalyst substance are alkaline or acidic metal salts, and the catalyst (1), the catalyst (2a), and the catalyst (2b) are immersed in an immersion liquid obtained by dissolving the metal salts in water.
The carrier is immersed and supported. In this case, it may be immersed in a mixed aqueous solution of a plurality of metal salts to be simultaneously supported, or may be prepared by individually preparing an aqueous solution of metal salts and supported by immersion. Further, in order to stabilize the immersion liquid, it is preferable to add a small amount of ammonia water, hydrogen peroxide solution, gluconic acid, plosic acid, citric acid, malic acid, EDTA (ethylenediaminetetraacetic acid) or the like.

The aqueous metal solution of the Group 8 metal usually uses a water-soluble carbonate or nitrate.
0-40% by weight aqueous solution, preferably 25% by weight
An aqueous solution is used. Further, as the Group 6A metal, a water-soluble ammonium salt can be used, for example, a 10 to 25 wt% aqueous solution of ammonium molybdate, preferably 15
A weight% aqueous solution is used.

The Group 1A metal, which is a hydrogenation active component specific to the catalyst (2b), may be a water-soluble carbonate or nitrate, for example, sodium nitrate is used. Similarly, a phosphorus compound can be used as the Group 5B element which is a hydrogenation active component unique to the catalyst (2b), and for example, orthophosphoric acid (orthophosphoric acid) is used.

After immersing the carrier in the aqueous metal salt solution for about 30 to 60 minutes, it is dried at room temperature to 200 ° C. for about 0.5 to 16 hours under an air stream, and then dried under an air stream for 200 hours. ~ 800 ° C, preferably 450-650 ° C
By carrying out calcination for about 1 to 3 hours under the above heating conditions, the catalyst supporting each metal oxide is completed.

It is important that the porous catalyst having a large number of pores completed by the above-mentioned production method has the following specific surface area and pore size distribution in order to achieve a desired object by combining them.

The specific surface area of the catalyst (1) is 100 to 180 m ²
/ G, preferably 150 to 170 m ² / g. If the specific surface area is less than 100 m ² / g, the catalytic performance will be insufficient. On the other hand, if it exceeds 180 m ² / g, the desired pore size distribution is often not obtained, and even if it is obtained by an additive or the like, an increase in hydrogenation activity due to a high specific surface area causes an increase in sedimentation. Become.

The specific surface area of the catalyst (2a) is 100 to 180.
m ² / g, preferably from 150~170m ² / g. If the specific surface area is less than 100 m ² / g, the catalytic performance will be insufficient.
Further, even if it exceeds 180 m ² / g, there is no increase in catalyst performance. The specific surface area of the catalyst (2b) is 150 meters ² / g or more, preferably 185~250m ² / g. Specific surface area of 150m ² / g
If it is less than the above range, the catalyst performance will be insufficient. Here, the specific surface area is a specific surface area obtained by the BET formula by nitrogen (N ₂ ) adsorption.

Further, the total pore volume measured by mercury porosimetry is 0.55 ml / g or more, preferably 0.6 to 0.5, common to the catalyst (1), the catalyst (2a) and the catalyst (2b). 9 ml / g
Is. If it is less than 0.55 ml / g, the catalyst performance will be insufficient. Here, the measurement by the mercury intrusion method is, for example, using a mercury porosity measuring device “Autopore II” (trade name) manufactured by Micromeritics Co., with a contact angle of 140 ° and a surface tension of 480 dyne / cm. It is a value obtained by measuring under the conditions.

In the catalyst (1), the ratio of the volume having a diameter of 200Å or more is 50% or more of the total pore volume, preferably 6
It is in the range of 0 to 80%. (Here, in the present specification, the symbol “Å” represents angstrom, which is a unit of length.
Å = 10 ^-10 m). When the volume ratio of the pores having a diameter of 200Å or more is less than 50% of the total pore volume, the catalyst performance, particularly the asphaltene decomposition performance is deteriorated, and the suppression of the formation of the sediment is insufficient. In the carrier before the metal oxide is supported, the total volume ratio of the pores is 43% or more, preferably 45 to 70% of the total pore volume.

The catalyst (1) has a diameter of 2,000.
Volume ratio of pores Å or more is 10 to 30% of total pore volume
Is. If the proportion is less than 10%, the deasphaltenizing performance is deteriorated at the final outlet of the reactor, and the generation of sediment is increased, and if it exceeds 30%, the mechanical strength of the catalyst becomes brittle even if it becomes extremely low, and it is not suitable for commercial use. I can't stand enough.

Further, in the case of treating a stock oil having a large amount of vacuum residual oil, in the catalyst (1), the total volume ratio of pores having a diameter of 100 to 1,200Å is based on the total pore volume. It is preferably 82% or less, and particularly preferably 80% or less.
If the ratio exceeds 82%, the ratio of the total volume of pores of 2,000 Å or more is relatively decreased, and the diffusion of the extra heavy fraction required in the first stage in the catalyst pores becomes insufficient. This is because it tends to cause a reduction in the decomposition rate of the vacuum residue fraction.

In the catalyst (1), the diameter of the pores is 500.
The pore volume of ~ 1,500 Å is preferably less than 0.2 ml / g. When it exceeds 0.2 ml / g, pores with a diameter of 300 Å or less, which are effective for desulfurization and demetallization, are relatively decreased. This is because the catalytic performance is likely to be lowered. further,
This is because pores with a diameter of 300 Å or less are likely to be clogged with the super-heavy component, which may shorten the catalyst life. The catalyst (1) has a pore diameter distribution of 10
The proportion of the pore volume of 0 Å or less is preferably 25% or less of the total pore volume. If it exceeds 25%, hydrogenation to components other than asphaltene will be highly advanced, and the production of sediment tends to increase.

The catalyst (2a) has a pore volume distribution of 85% or more, and more desirably 87% or more, of the pore volume having a diameter of 100 to 1,200Å based on the total pore volume.
If the volume ratio of 100 to 1,200 Å is less than 85%, hydrogenation reactions such as desulfurization and decomposition will not be sufficiently exhibited.

In the catalyst (2b), it is preferable that the ratio of the volume of pores having a diameter distribution of 100 to 1,200Å is 75% or more, more preferably 78% or more, based on the total pore volume. If the proportion of the pore volume of 100 to 1,200 Å is less than 75%, hydrogenation reactions such as desulfurization and decomposition cannot be sufficiently exhibited.

In both the catalyst (2a) and the catalyst (2b), the proportion of pore volume having a diameter of 4,000 Å or more is 0 to 2%, and the proportion of pore volume having a diameter of 10,000 Å or more is 0 to 1%. This makes it possible to prevent desulfurization and hydrogenation activity, particularly, an extreme reduction in the decomposition rate of the vacuum residue oil fraction.

Further, in both the catalyst (2a) and the catalyst (2b), it is preferable that the proportion of the pore volume having a diameter of 100 Å or less is 25% or less of the total pore volume as the pore distribution. If it exceeds 25%, hydrogenation to components other than asphaltene will be highly advanced, and the production of sediment tends to increase.

In the catalyst (2a), the ratio of the volume of pores having a diameter of 200Å or more is 50% or more, preferably 60 to 80% of the total volume of pores. If the ratio of the volume of pores having a diameter of 200Å or more is less than 50% of the total volume of pores, the asphaltene decomposition performance becomes insufficient and the suppression of the formation of sediment becomes insufficient.

On the other hand, in the catalyst (2b), the ratio of the volume of pores having a diameter of 200Å or more is less than 50% of the total volume of pores, preferably 40% or less. When the ratio of the volume of pores with a diameter of 200Å or more is 50% or more of the total volume of pores, the hydrogenation activity is lowered, so that proper hydrogenation of the asphaltene decomposed by the catalyst (2a) cannot be performed and the formation of sediment occurs. Cannot be suppressed. In addition, the desulfurization performance also deteriorates, so the catalyst (2
The effect of addition to a) is also lost.

In the second stage of hydrotreating, the catalyst (2
Ratio of catalyst (2b) mixed with a), ie (2b)
/ [(2a) + (2b)] is 1% by weight or more, but a preferable ratio is 1 to 50% by weight, and more preferably 10 to 30%.
% By weight. If the mixing ratio exceeds 50% by weight,
Since the hydrogenation in the second stage progresses excessively, there is a tendency that the formation of sediment becomes remarkable. On the other hand, if it is less than 1% by weight, the desulfurization performance will be insufficient.

[II] Hydrotreatment Method The heavy hydrocarbon oil that is the object of the hydrotreatment of the present invention is a petroleum-based residual oil, solvent deasphalted oil, coal liquefied oil, shale oil, tar sand oil, typical Atmospheric pressure residual oil (AR) and reduced pressure residual oil (V
R) and mixtures thereof, especially vacuum residue.

In particular, a component boiling at 538 ° C. or higher (vacuum residual oil fraction) is 80% by weight or more, sulfur is 3% by weight or more, residual carbon is 10% by weight or more, and other impurities containing high-concentration metals are present. A heavy oil containing a is suitable as an object of the hydrotreatment of the present invention, and by combining the above catalysts,
It is possible to remove impurities and convert to light oil.

As the first and second reactors in the hydrotreating, general ones having a fixed bed, a moving bed or a boiling bed can be used. However, since the reaction temperature can be kept uniform, the mode of the boiling bed can be used. It is preferable to carry out the hydrotreatment.

Specifically, a cylindrical catalyst having a diameter of 0.9 to 1.0 mm and a length of 3.5 mm is charged in a reactor, and hydrocarbon oil is in a liquid phase at a total liquid space velocity (LHSV) of 0. .1 to 3 hours
^-1 , preferably at 0.3 to 2.0 hr ^-1 , while hydrogen is in a flow ratio (H ₂ / Oil) of hydrocarbon oil of 300 to 1.5.
The reaction is carried out at a pressure of 5 to 25 MPa, preferably 14 to 19 MPa, and a temperature of 350 to 450 ° C, preferably 400 to 440 ° C.

As a mode of mixing the catalyst (2a) and the catalyst (2b) in the second reaction device, the catalyst (2a) and the catalyst (2b) are packed so as to be mixed uniformly in the fixed bed, but in the case of a moving bed or a boiling bed, the catalyst (2a) is mixed. ) May be charged and then the catalyst (2b) may be gradually charged. Further, the first reactor and the second reactor may be connected in series, but a stripping step for removing hydrogen sulfide and a quench line for supplying hydrogen may be provided in the middle of both the reactors.

[0074]

The present invention will be described in more detail with reference to the following examples. However, the following examples do not limit the present invention. [I] Manufacture of catalyst Manufacture of catalyst A (corresponding to catalyst (1) above) (i) Manufacture of carrier A sodium aluminate solution and an aluminum sulfate solution were added dropwise at the same time to a tank containing tap water to carry out mixing. It was The pH during mixing, the temperature was 77 ° C., and the holding time was 70 minutes. Such an admixture resulted in a gel of alumina hydrate. The alumina hydrate gel obtained in the above step was separated from the solution, and then washed with warm water to remove impurities in the gel. Then, after kneading for about 20 minutes using a kneading machine to improve the moldability of the gel, extrusion molding was performed using a molding machine into cylindrical particles having a diameter of 0.9 to 1 mm and a length of 3.5 mm. Finally, the formed alumina gel was dried in the presence of air at 120 ° C for 16 hours, and then dried at 800 ° C for 2 hours.
It was calcined for an hour to obtain an alumina carrier.

(Ii) Preparation of catalyst 100 m of citric acid solution to which 17.5 g of ammonium molybdate tetrahydrate and 9.8 g of nickel nitrate hexahydrate were added.
100 g of the above alumina carrier was immersed in l at 25 ° C. for 45 minutes to obtain a metal component-supporting carrier. Then, the carrier was dried at 120 ° C. for 30 minutes using a dryer, and then 620
The catalyst was completed by calcining in a kiln at 1.5 ° C. for 1.5 hours.
The amounts and properties of each component in the produced catalyst A are as shown in Table 1 below.

Production of catalyst B (corresponding to the above catalyst (2a)) (i) Production of carrier A sodium aluminate solution and an aluminum sulfate solution were simultaneously added dropwise to a tank containing tap water to carry out addition mixing. The pH at the time of mixing was 8.5, the temperature was 65 ° C., and the holding time was 70 minutes. Such an admixture resulted in a gel of alumina hydrate. The alumina hydrate gel obtained in the above step was separated from the solution, and then washed with warm water to remove impurities in the gel. Then, after kneading for about 20 minutes using a kneading machine to improve the moldability of the gel, extrusion molding was performed using a molding machine into cylindrical particles having a diameter of 0.9 to 1 mm and a length of 3.5 mm. Finally, the formed alumina gel was dried in the presence of air at 120 ° C for 16 hours, and then at 900 ° C for 2 hours.
It was calcined for an hour to obtain an alumina carrier.

(Ii) Preparation of catalyst 100 m of citric acid solution to which 16.4 g of ammonium molybdate tetrahydrate and 9.8 g of nickel nitrate hexahydrate were added.
100 g of the above alumina carrier was immersed in l at 25 ° C. for 45 minutes to obtain a metal component-supporting carrier. Then, the carrier is dried at 120 ° C. for 30 minutes using a dryer, and then 600
The catalyst was completed by calcining in a kiln at 1.5 ° C. for 1.5 hours.
The amounts and properties of each component in the produced catalyst B are as shown in Table 1 below.

Catalyst C (corresponding to catalyst (2b) above)
(I) Production of carrier A sodium aluminate solution was placed in a tank containing tap water, and the mixture was mixed using an aluminum sulfate solution. At the end of the addition of the aluminum sulfate solution, the pH was adjusted to 8.5, the mixing temperature was 64 ° C, and the holding time was 1.
It was set to 5 hours. Next, silica glass water glass (sodium silicate) was mixed. Water glass was placed in the tank with the aluminum sulfate solution. The concentration of sodium silicate in the alumina gel at this time was set to 1.6% by weight.
After separating the silica-alumina hydrate gel obtained by the step from the solution, a washing treatment is performed using warm water,
The impurities in the gel were removed. Then, using a kneader 1
After kneading for a long time to improve the moldability of the gel, it was extrusion-molded by a molding machine into cylindrical particles having a diameter of 0.9 to 1 mm and a length of 3.5 mm. The finally molded silica-alumina particles were dried in the presence of air at 120 ° C. for 16 hours, and then 8
It was calcined at a temperature of 00 ° C. for 2 hours to obtain a silica-alumina carrier. The silica content in the obtained carrier was 7% by weight.

(Ii) Preparation of catalyst 16.2 g of ammonium molybdate tetrahydrate, 4.7 g of nickel carbonate, 0.66 g of sodium nitrate, 2.1 g of orthophosphoric acid and 25 g of 100 g of the above silica-alumina carrier.
By immersing at 45 ° C. for 45 minutes, a metal component-supporting carrier was obtained. Then, the carrier was dried using a dryer at 120 ° C. for 30 minutes and then calcined in a kiln at 540 ° C. for 1.5 hours to complete a catalyst. The amounts and properties of each component in the produced catalyst C are as shown in Table 1 below.

Manufacture of catalyst D (i) Manufacture of carrier Aluminum sulfate and sodium aluminate solutions were simultaneously added dropwise to a tank filled with tap water and mixed. The temperature at the time of mixing was 70 ° C., the pH at the time of dropping was 7.5, and the final p
More sodium aluminate was added until H was 9.5.
The holding time is 70 minutes. The obtained alumina gel was molded and fired in the same manner as in Example 1 to obtain alumina particles.

(Ii) Preparation of catalyst Aqueous citric acid solution 10 to which 17.2 g of ammonium molybdate tetrahydrate and 9.8 g of nickel nitrate hexahydrate were added.
100 g of the alumina carrier was immersed in 0 ml at 25 ° C. for 45 minutes, dried and baked under the same conditions as in Example 1 to obtain a metal component-supported carrier. The amounts and properties of each component in the produced catalyst D are as shown in Table 1 below.

[0082]

[Table 1]

(II) Hydrotreatment Table 2 shows the properties of the feedstock oil. This raw oil is 5
Containing about 93% by weight of components having a boiling point above 38 ° C, sulfur content of about 4.9% by weight, total nitrogen content of about 3%
It contains 300 wt ppm, a vanadium content of 109 wt ppm, a nickel content of 46 wt ppm, and an asphaltene content represented by a normal heptane insoluble content of about 8 wt%.

[0084]

[Table 2]

Catalyst A, Catalyst B, Catalyst C and Catalyst D
Was packed in the fixed bed of the reactor with the combinations shown in Tables 3 and 4, and hydrotreated for each. The raw material oil having the properties shown in Table 2 was used at a pressure of 16.0 MPa and a total liquid space velocity (LHSV) of 1.
5 hr ⁻¹ , average temperature 427 ° C., introduce hydrogen into the fixed bed at a ratio of hydrogen to feed oil (H ₂ / Oil) of 800 Nl / L,
A product oil was obtained. The produced oil is collected and analyzed to calculate the amount of sulfur (Sulfur), metal (vanadium + nickel) and asphaltene (Asp.) Desorbed by hydrogenation, and the specific activity (Relative Volume Activity) is calculated based on the following formula. ; RV
A) was determined and shown in Tables 3 and 4. Specific activity is shown in Comparative Example 1
Hydrodesulfurization (HDS), hydrodemetalization (HD
M) and hydrodeasphalten (HDAsp.) Indices.

[0086]

[Equation 1]

[0087]

[Table 3]

[0088]

[Table 4]

From the results of Tables 3 and 4 above, Example 1
In Example 2, in the treatment of a vacuum residue containing a heavy fraction, compared with Comparative Examples of various combinations, advanced desulfurization, demetalization, while suppressing the generation of sediment which is a problem in the petroleum refining process, It is understood that asphaltene degradation has been achieved.

[0090]

According to the present invention, a heavy hydrocarbon oil containing a large amount of impurities such as sulfur, residual carbon, metal, nitrogen and asphaltene, particularly a heavy oil containing a vacuum residue fraction of 80% by weight or more. In the hydrotreatment of a heavy oil, it is possible to produce a distillate with a high degree of removal of contaminants and a high added value while suppressing the formation of a sediment that hinders the operation of the equipment. Further, by removing asphaltene to a high degree in the first stage of the hydrotreatment, it is possible to suppress the generation of undesired coke deposited on the catalyst in the thermal decomposition in the second stage and prevent the deterioration of the catalyst performance.

Continued front page    F-term (reference) 4G069 AA03 AA08 BA01A BA01B                       BA03A BA03B BB04A BB04B                       BC01A BC02B BC25A BC26A                       BC27A BC57A BC59B BC65A                       BC68B BC69A BD06A BD07A                       BD07B CC02 CC03 CC16                       DA05 EA06 EC03X EC03Y                       EC07X EC07Y EC15X EC15Y                       EC16X EC16Y EC17X EC17Y                       EC18 FA01 FB08 FB14 FB67                       FC08                 4H029 CA00 DA00 DA09

Claims (8)

[Claims] 1. A heavy hydrocarbon oil is contacted with a catalyst (1) in the presence of hydrogen in a first reactor filled with the following catalyst (1) to carry out a first stage hydrotreatment, and then, The hydrotreated oil obtained in the first stage was treated with the catalyst (2
a) and the catalyst (2b) are mixed and packed in the second reactor in the presence of hydrogen, the catalyst (2a) and the catalyst (2)
A method for hydrotreating a heavy hydrocarbon oil, comprising carrying out a second stage hydrotreatment in contact with b). Catalyst (1): 7 to 20% by weight of an oxide of a Group 6A metal of the periodic table and 0.5 to 6 of an oxide of a Group 8 metal of the periodic table on the basis of the catalyst weight on a porous alumina carrier. % Of the catalyst, (a) the specific surface area of the catalyst is 100 to 180 m ² / g, (b) the total pore volume is 0.55 ml / g or more, and the pore distribution diameter of the catalyst is the total pore volume. As a standard, (c1) the proportion of pore volume of 200 Å or more is 50% or more of the total pore volume, and (c2) proportion of pore volume of 2,000 Å or more is 10 to 30% of the total pore volume. , (C3) Hydrotreating catalyst in which the proportion of pore volume having a diameter of 10,000 Å or more is 0 to 1% of the total pore volume; Catalyst (2a): Periodic on a porous alumina carrier based on the catalyst weight. 7 to 20% by weight of Group 6A metal oxide in the table,
Oxide of Group 8 metal of the periodic table is supported in an amount of 0.5 to 6% by weight, (a) specific surface area of the catalyst is 100 to 180 m ² / g, (b) total pore volume is 0.55 ml. / G or more, the pore distribution diameter of the catalyst is based on the total pore volume (d1) the proportion of the volume of 100 to 1,200 Å is 85%
As mentioned above, (d2) the ratio of the volume of pores having a diameter of 4,000 Å or more is 0 to
2%, (d3) Percentage of pores with a diameter of 10,000 Å or more is 0
~ 1%, (d4) hydrotreating catalyst in which the proportion of pore volume having a diameter of 200Å or more is 50% or more of the total pore volume; catalyst (2b): at least one hydrogen in a heat-resistant inorganic porous carrier Of the catalyst, (a) the specific surface area of the catalyst is 150 m ² / g or more, (b) the total pore volume is 0.55 ml / g or more, and the pore distribution diameter of the catalyst is less than the total pore volume. As a standard, (d1) the proportion of the pore volume of 100 to 1,200 Å is 75% or more of the total pore volume, (d2) the proportion of the volume of 4,000 Å or more is 0 to 2%, (d3) Hydrotreating in which the proportion of pore volume having a diameter of 10,000 Å or more is 0 to 1% of the total pore volume, and (d4) the proportion of pore volume of 200 Å or more in diameter is less than 50% of the total pore volume. Catalyst. 2. The method according to claim 1, wherein the heat-resistant inorganic porous carrier of the catalyst (2b) is a silica-alumina carrier containing 3.5% by weight or more of silica. 3. The catalyst (2b) has a silica content of 3.5.
Silica-alumina carrier containing more than 10 wt% of the oxide of Group 6A metal of the periodic table is 7 to 20 wt% and oxide of Group 8 metal of the periodic table is 0.5 to 6 wt% based on the weight of the catalyst. ,
The process according to claim 1, which is a hydrotreating catalyst in which an oxide of a Group 1A metal of the periodic table is supported in an amount of 0.1 to 1% by weight. 4. The catalyst (2b) has a silica content of 3.5.
Silica-alumina carrier containing more than 10 wt% of the oxide of Group 6A metal of the periodic table is 7 to 20 wt% and oxide of Group 8 metal of the periodic table is 0.5 to 6 wt% based on the weight of the catalyst. ,
A hydrotreating catalyst comprising 0.1 to 1% by weight of an oxide of a Group 1A metal of the periodic table and 0.1 to 2% by weight of an oxide of a Group 5B element of the periodic table. The method of claim 1, wherein: 5. The heavy hydrocarbon oil comprises a vacuum residue fraction of 80%.
It is a heavy oil containing at least 5% by weight.
The method described in the section. 6. A temperature of 3 in the first step and the second step.
The method according to any one of claims 1 to 5, wherein the hydrogenation treatment is performed under the conditions of 50 to 450 ° C and a pressure of 5 to 25 MPa. 7. The method according to claim 1, wherein the mixture ratio of the catalyst (2b) in the catalyst packed in the second stage reactor is 1% by weight or more. 8. The process according to claim 1, wherein the heavy hydrocarbon oil is contacted with the hydrotreating catalyst in the form of a boiling bed.