JP2000109860A - Light oil and hydrodesulfurization process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a light oil having a sulfur content reduced and an excellent color hue, by performing hydrodesulfurization at the first process and thereafter additionally performing hydrodesulfurization at the second process under a press. higher than that of the first process. SOLUTION: A light oil distillate of a sulfur-contg. petroleum hydrocarbon is hydrodesulfurized under the first process reaction condition at a temp. of 320-380 deg.C, a press. of 4-7 MPa, an LHSV of 0.5-3 h-1 and a hydrogen/oil ratio of 500-2,000 scfb to make a sulfur content in the raw material oil 0.05 wt.% or less. Successively, the resulting material is hydrodesulfurized under the second process reaction condition at a temp. of 320-380 deg.C, a press. of 10-15 MPa, an LHSV of 0.5-2 h-1 and a hydrogen/oil ratio of 1,000-5,000 scfb to give a light oil product with a sulfur content of 0.001 wt.% or less and a Saybolt color of +20 OAT higher. A catalyst in the first process is pref. a catalyst in which Co or Mo is supported on an alumina carrier, and a catalyst in the second process is, as for the inlet part, a catalyst pref. in which Ni and Mo are supported on an alumina/zeolite carrier, and as for the outlet part, is a catalyst pref. in which either Co or Ni and Mo are supported on an alumina carrier.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a process for hydrogas desulfurization of a gas oil fraction of petroleum hydrocarbon containing sulfur, a combination of specific processes, a reactor configuration, a catalyst, and gas oil under specific reaction conditions. The present invention relates to a method for ultra-depth desulfurization and light oil having excellent properties obtained by the method.

[0002]

2. Description of the Related Art Straight-run gas oil obtained by distillation of crude oil and cracked gas oil obtained by cracking heavy oil contain a sulfur compound, and its amount is 1 to 3% by weight as sulfur. When light oil containing a sulfur compound is used as a diesel fuel, it is discharged into the atmosphere as SOx and pollutes the environment. Therefore, these gas oils are usually used as fuel after hydrodesulfurization treatment to remove sulfur compounds. The allowable amount of sulfur contained in diesel fuel is 0.05 according to JIS standards.
In order to achieve this value, large so-called deep desulfurization units have been constructed and used. In the future, in order to mount a purification catalyst for reducing NOx in exhaust gas on diesel vehicles and to recycle part of exhaust gas (EGR), a technology to further reduce the amount of sulfur, ie, super It is said that deep desulfurization technology is necessary.

[0003] Conventionally, a catalyst in which cobalt or nickel and molybdenum are supported on an alumina carrier has been used for the desulfurization of light oil. However, with this conventional catalyst, 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene are difficult to desulfurize, and the desulfurized product requires a sulfur content of 0.05% by weight or less to desulfurize it. There is a problem that the temperature and pressure must be extremely high, and the construction cost and operation cost of the device become extremely large. As a method for increasing the desulfurization activity of these difficult-to-desulfurize sulfur compounds, a catalyst in which phosphorus or boron is contained in a catalyst carrier (Japanese Patent Laid-Open No. 52-13503).
And zeolite added to a carrier (Japanese Patent Laid-Open No. 7- 1970)
39) have been reported. These catalysts have Brönsted acid sites and have a high ability to isomerize the methyl group of (di) methyldibenzothiophene or hydrogenate the phenyl group, such as 4-methyldibenzothiophene and 4,6-
High activity against desulfurization of dimethyldibenzothiophene.

However, these high-performance catalysts have also been studied on the assumption of so-called deep desulfurization up to a level of about 0.05% by weight, and are even lower, for example, 0.005% by weight.
It has never been used in research on ultra-deep hydrodesulfurization up to such a level, and in fact, according to the research conducted by the present inventors, it is possible to obtain a level of only 0.005% by weight by using these catalysts in combination with the conventional process. It turned out that desulfurization was almost impossible. Research has been conducted to achieve deep desulfurization from the aspect of a reactor. For example, Japanese Patent Application Laid-Open No. 5-78670 proposes a method of performing depth desulfurization without deteriorating the hue by a two-step reaction under different reaction conditions. A process has been proposed in which the space velocity of the two reactors is lower than the space velocity of the first reactor. Japanese Patent Application Laid-Open No. 6-25677 proposes a process in which the temperature of the second reactor is lower than the temperature of the first reactor.

However, the above-mentioned new high-performance catalyst has a serious problem. That is, alkylbenzothiophenes and dibenzothiophenes having no alkyl substituent at the 4- or 6-position, such as dibenzothiophene,
For 1-, 2- or 3-methylbenzothiophene and the like, the catalyst obtained by adding phosphorus or zeolite to the carrier of the catalyst is desulfurized more than the conventionally used catalyst which supported cobalt and molybdenum on an alumina carrier. Low activity (F. van Looij et al., Applied Catalysis A: General
170, 1-12 (1998)). That is, it is not necessarily effective for desulfurization of petroleum gas oil fractions containing various sulfur compounds. Also, because of the presence of Bronsted acid sites,
When the product is easily colored and a raw material containing an olefin is used, or when used for a reaction at a high temperature of 350 ° C. or higher, thiol or sulfide may be generated to lower the desulfurization rate in some cases. Further, there is a large problem that the olefin component is polymerized at the Bronsted acid point to precipitate coke, and the catalyst is quickly deactivated. Even when the feedstock oil does not contain olefins, if sulfur compounds are desulfurized, olefins are produced, which causes coke to precipitate. This indicates that the coking rate when thiophene was passed was 10 times lower than that when olefins and aromatics were passed.
(Catalysis Revie
w, 24, (3), 343 (1982)). Further, even in the proposal from the improvement of the above-described apparatus, the method of performing the depth desulfurization without deteriorating the hue by the two-stage reaction under different reaction conditions is effective for the improvement of the hue, but further advances the depth desulfurization. There is almost no effect, and desulfurization to a level of 0.005% by weight is not considered at all, and it is hard to say that the process has been proposed as a measure for ultra-deep desulfurization.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to obtain a light oil having a much lower sulfur content and a lower coloration as compared with the prior art, and to obtain the light oil. To provide an ultra-deep desulfurization method.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by using a specific combination of steps, an apparatus configuration, a specific reaction condition, and a specific catalyst, the light oil is used. And found a method for ultra-depth desulfurization, and completed the present invention.

According to the present invention, when hydrodesulfurizing a gas oil fraction of a petroleum hydrocarbon containing sulfur, after hydrodesulfurization in the first step, hydrogen is further applied in the second step at a higher pressure than in the first step. This is a hydrodesulfurization method for hydrodesulfurization. Further, the present invention is a light oil obtained by the above method and having a sulfur content of 0.001% by weight or less and a Saybolt color of +20 or more. Other specific embodiments of the present invention and the operation thereof will be described in detail below.

In the present invention, in the course of hydrodesulfurization, first, among the sulfur compounds contained in the gas oil in the first step, alkylbenzothiophenes and dibenzothiophene having no alkyl substituent at the 4- or 6-position. It is important to achieve almost complete desulfurization of this type. In particular, when desulfurization is performed in the first step so that the sulfur content is 0.05% by weight or less, alkylbenzothiophenes and
The desulfurization rate of dibenzothiophenes having no alkyl substituent at the-or 6-position is 99% by weight or more, and the effects of the present invention can be maximized. The reaction conditions in the first step are the same as those used in conventional deep desulfurization, and the temperature is 32.
0-380 ° C, pressure 4-7MPa, LHSV 0.5-3
A range of h ^-1 and a hydrogen / oil ratio of 500 to 2000 scfb is appropriate. More preferably, the temperature is 330 to 360 ° C,
The pressure ranges from 4 to 7 MPa, the LHSV ranges from 1.0 to 2 h ^-1 , and the hydrogen / oil ratio ranges from 1000 to 2000 scfb. The reaction pressure in the present invention refers to the total pressure in the reactor. As the catalyst, an ordinary hydrodesulfurization catalyst, that is, a catalyst in which cobalt or nickel and molybdenum or tungsten are supported on a porous carrier can be used. Preferably, when a catalyst in which cobalt and molybdenum are supported on a porous carrier mainly composed of alumina is used, the desulfurization rate of alkylbenzothiophenes and dibenzothiophenes having no alkyl substituent at the 4- or 6-position is high. It is advantageous. This catalyst does not have a particularly high desulfurization activity for 4-methyldibenzothiophene or 4,6-dimethyldibenzothiophene, but it still desulfurizes at least 90% by weight of these hardly desulfurizable sulfur compounds. Can be. As the hydrogen used in the first step, hydrogen not containing hydrogen sulfide may be used, or hydrogen containing hydrogen sulfide separated and recovered at the outlet of the second step may be used.

The distillate oil hydrodesulfurized in the first step includes:
Although the absolute amount is small, it contains hardly desulfurizable sulfur compounds such as 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene, and these sulfur compounds are further desulfurized in the second step. Here, the most characteristic feature of the present invention is that hydrodesulfurization is performed at a higher pressure in the second step than in the first step. As a result of intensive studies by the present inventors, it is preferable to increase the total pressure of the reactor in order to achieve ultra-depth desulfurization. It has been found that when the pressure in the step is higher than that in the first step, the desulfurization reaction is accelerated and a product oil having excellent hue can be obtained. The advantages of the two-step process are that it can provide the most suitable catalysts and reaction conditions for each of the easily desulfurized sulfur compound and the hardly desulfurized sulfur compound, and can freely control the hydrogen partial pressure and hydrogen sulfide concentration at the entrance of the second step. It can be designed and controlled.

The preferred reaction conditions in the second step are as follows: temperature 320-380 ° C., pressure 10-15 MPa, LHSV
0.5-2 h ^-1 , hydrogen / oil ratio 1000-5000 scf
b, more preferably, a temperature of 330 to 360 ° C.,
Pressure 10-15 MPa, LHSV 0.5-2 h ^-1 , hydrogen
/ Oil ratio is in the range of 1000-3000 scfb. In particular, setting the reaction pressure to a higher value gives better results in terms of desulfurization rate and hue. When the reaction temperature is set as low as possible, the effect of improving the hue is greater, and the reaction temperature can be set lower than in the first step.

The fact that the reaction pressure in the second step is higher than that in the first step is a major feature of the present invention. In the prior art, there are some which employ a two-step process in order to prevent coloring of the product. However, as mentioned above, these are focused only on the reaction temperature and the contact time, and the reaction pressure is very careful. Was not paid. This is to supply the raw material and hydrogen gas continuously from the first step to the second step,
In the present invention, the hydrogen sulfide may be continuously supplied, but once the gas component and the liquid component are separated, and in the second step, a new hydrogen gas containing almost no hydrogen sulfide is supplied to hydrogenate the hydrogen sulfide. The reaction inhibition effect on desulfurization can be eliminated.

Although the reaction pressure in the second step of the prior art employing a two-step process is 3 to 7 MPa, the preferred reaction pressure is limited to 10 to 15 MPa in the present invention. The hydrodesulfurization reaction is carried out under pressure conditions that have not been achieved. Therefore, the problem of the coloring of the product, which was uneasy in the prior art, was completely solved, and the hue of the product was 0 or more in Saybolt color while the sulfur content was less than 0.005% by weight. In most cases, excellent products exceeding +20 can be obtained. Furthermore, because a pressure of 10 to 15 MPa is adopted,
The reaction can proceed at a lower temperature than in the prior art, and the hydrogenation reaction of aromatic hydrocarbons contained in the feed gas oil fraction can proceed advantageously on thermodynamic equilibrium. Therefore, the content of the aromatic hydrocarbon in the product obtained by the present invention is extremely lower than that of the conventional technology, and a high-quality product with less black smoke emission when used as a diesel fuel can be produced. As described above, the present invention is completely different from the prior art. In the prior art, the product obtained had a sulfur content of 0.05% by weight and a Saybolt color of about 0. It is also evident from the fact that the content is less than 0.005% by weight and the Saybolt color is as excellent as +20 or more.

Although a usual desulfurization catalyst can be used in the second step, it is preferable to use a catalyst having a high desulfurization activity for 4-methyldibenzothiophene and 4,6-dimethyldibenzothiophene, for example, 85 to 99% by weight of alumina. And a catalyst in which nickel and molybdenum are supported on a porous carrier containing 1% to 15% by weight of zeolite. More preferably, the ratio of alumina to zeolite is 90 to 97% by weight of alumina and 3 to 10% by weight of zeolite. However, this catalyst is characterized in that thiols, sulfides and coloring substances are produced as side reactions. for that reason,
40 to 80% by volume from the entrance of the catalyst in the second step
Is filled with a catalyst in which nickel and molybdenum are supported on a porous support containing 85 to 99% by weight of alumina and 1 to 15% by weight of zeolite. When a catalyst supporting nickel and molybdenum is used, thiols, sulfides, and coloring substances by-produced by the zeolite-containing catalyst are hydrogenated by the subsequent catalyst, so that light oil having a low sulfur content and excellent hue can be produced.

In the second step, the hydrogen gas used has a hydrogen purity of 65% by volume or more and a hydrogen sulfide concentration of 0.0%.
It is desirable that the content be 5% by volume or less. More preferably, the hydrogen purity is 70% by volume or more and the hydrogen sulfide concentration is 0.01% by volume or less. This is to prevent the inhibition of the desulfurization reaction due to the adsorption of hydrogen sulfide to the catalytic active site,
This is for minimizing thiol and sulfide by-products. As this hydrogen, unused hydrogen not containing hydrogen sulfide produced in a hydrogen production device or a gasoline reforming device may be used, or hydrogen separated at the first or second step outlet may be subjected to amine absorption. It may be used after removing hydrogen sulfide by an apparatus.

The above steps are repeatedly used, and the reaction conditions are set to a pressure of 10 MPa or more and a reaction temperature of 320 to 360.
C., a hydrogen / oil ratio of 2000 to 5000 scfb, wherein the catalyst used in the first step is a catalyst in which cobalt and molybdenum are supported on a porous carrier mainly composed of alumina,
The catalyst used at the entrance of the second step is alumina 85-85.
A catalyst comprising nickel and molybdenum supported on a porous carrier containing 99% by weight and 1 to 15% by weight of zeolite, wherein the ratio of the second step to the total catalyst is 40 to 80% by volume; By using a catalyst in which cobalt or nickel and molybdenum are supported on a porous carrier whose main component is alumina, the sulfur content is 0.001.
% Or less and the Saybolt color can be almost +30.

The amount of the active metal supported on the catalyst used in the present invention may be the amount used in a general diesel fuel desulfurization catalyst. That is, assuming that the weight of the carrier is 100 parts by weight (weight including zeolite), Co or Ni is 1 to 10 parts by weight, preferably 3 to 6 parts by weight in terms of oxide, and Mo is 10 to 30 parts by weight in terms of oxide. Parts, preferably 15 to 25 parts by weight. When the amount of metal is small, the activity becomes insufficient, and the deactivation rate of the catalyst increases. On the other hand, if it is too much, the activity is saturated, which is uneconomical.

In the second step of the present invention, alumina 85 to 99 is used.
It is preferable to use a catalyst in which nickel and molybdenum are supported on a carrier containing 1% to 15% by weight of zeolite. In this case, the zeolite may be A-type zeolite, X-type zeolite, Y-type zeolite, L-type zeolite, MFI
Zeolite, mordenite and the like can be used. Among them,
U with dealuminated Y-type zeolite to improve thermal stability
SY-type zeolites are most preferred. These zeolites undergo ion exchange to develop Bronsted acid sites,
Ion exchange can be performed with protons, alkaline earth metals, rare earth metals, and the like. The zeolite may be mixed with an alumina gel, molded and calcined, or may be attached to the molded alumina carrier using a binder.

As a catalyst in each hydrogenation zone, a catalyst to which small amounts of various reforming components are added in order to improve desulfurization activity and the like may be used. For example, the addition of phosphorus improves the dispersion of the metal and increases the Bronsted acid sites, so that 4-methyldibenzothiophene and 4,4
Since the desulfurization activity of 6-dimethyldibenzothiophene is improved, it may be effective when added to the catalyst at the entrance of the second step. On the other hand, the addition of potassium or magnesium reduces the Bronsted acid point and suppresses the production of thiols and sulfides, and thus may be effective when added to the catalyst at the outlet of the second step.

The light oil to which the present invention can be applied is a straight-run gas oil, a catalytic cracking gas oil, a pyrolysis gas oil, etc., having a boiling point range of 200 to 380 ° C.
It is a fraction. The present invention is also effective for desulfurization of vacuum oil having a higher boiling point. The amount of sulfur contained in the feedstock is not particularly limited, but in the case of ordinary straight-run gas oil, it is 1-2% by weight.
It is about. The amount of sulfur in the produced oil can be arbitrarily determined as needed, and the required desulfurization rate can be achieved by optimizing reaction conditions such as reaction temperature, pressure, and liquid hourly space velocity. The light oil desulfurized by the present invention can be used as a regular or premium diesel fuel for light oil vehicles. It can also be used by mixing with heavy oil A or the like.

In each of the first and second steps of the present invention, a reactor of any type conventionally known, for example, any of a fixed bed and a moving bed may be used, and a down flow type and an up flow type may be used. The most suitable of these is a fixed bed down-flow reactor. Since this is a reactor type conventionally used for gas oil desulfurization,
Conventional devices can be used as they are. In general, a reactor in which one reactor is divided into a plurality of catalyst beds can be used. In each of the steps 1 and 2, the number of reactors is usually one. However, if necessary, a plurality of reactors may be used in series or in parallel. Since the inside of the reactor is a so-called trickle bed in which liquid and gas coexist, it is desirable to provide a distributor for uniformly dispersing the liquid on each catalyst bed. Further, depending on the heat generation state, quench hydrogen may be introduced at an optimum place to control the heat generation. In actual equipment, an extruded catalyst is used, and the catalyst is sock-filled or dense-filled in a conventional manner. After pre-sulfurizing the catalyst, the feed oil heated with hydrogen is passed through a reactor filled with the catalyst. The used catalyst may be used repeatedly by normal calcination and regeneration treatment.

[0022]

EXAMPLES The present invention will be described in more detail with reference to Examples. Example 1 As a first step, 5 parts by weight of cobalt (in terms of CoO) and 20 parts by weight of molybdenum (in terms of MoO ₃ ) were added to 100 parts by weight of γ-alumina carrier in a reaction tube of a fixed-bed down-flow reactor having an inner diameter of 1 inch. ) Was loaded in an amount of 300 ml. This catalyst was prepared by using a straight-run kerosene containing dimethyl disulfide (sulfur content: 3% by weight) at 300 ° C., 5 MPa, LH
Under the conditions of SV1h ^-1 and a hydrogen / oil ratio of 1000 scfb,
After pre-sulfurization for 4 hours, a Middle Eastern straight-run gas oil (boiling point 23
0-360 ° C, sulfur content 1.30% by weight) with hydrogen
Temperature 340 ° C, pressure 5MPa, LHSV1h ^-1 , hydrogen /
Oil was passed under the condition of an oil ratio of 1000 scfb to perform desulfurization. The sulfur content of the produced oil was 0.048% by weight. Further, as a second step, a carrier containing 97% by weight of γ-alumina and 3% by weight of proton-exchanged USY zeolite in the upper layer of the reaction tube of a fixed-bed down-flow type reactor having an inner diameter of 1 inch and 3 parts by weight of nickel ( 200 ml of a catalyst supporting NiO) and 20 parts by weight of molybdenum (MoO ₃ ) were filled,
In the lower part, 5 parts by weight of cobalt (Co
100 ml of a catalyst carrying 20 parts by weight of molybdenum (in terms of MoO ₃ ) and 20 parts by weight (in terms of MoO ₃ ). This catalyst was pre-sulfided for 4 hours under the conditions of 300 ° C., 12 MPa, LHSV ¹ h ⁻¹ , and hydrogen / oil ratio of 1,000 scfb using a straight-run kerosene containing dimethyl disulfide (sulfur content: 3% by weight), followed by a first reaction. The oil produced in the vessel together with hydrogen was at a temperature of 335 ° C.
Pressure 12MPa, LHSV1h ^-1 , hydrogen / oil ratio 2000
Desulfurization was performed by passing oil under the condition of scfb. The sulfur content of the produced oil is 0.004% by weight, and the color is Saybolt Color (JISK-
2580) to produce a +22 light oil.

Example 2 Instead of the catalyst of Example 1, 5 parts by weight of nickel (in terms of NiO) and 20 parts by weight of molybdenum (MoO) were used in the first and second reactors per 100 parts by weight of the γ-alumina carrier. _Three
(Converted) were loaded in 300 ml portions. The catalysts of both reactors were presulfurized in the same manner as in Example 1, and the gas oil of Example 1 was used at a temperature of 350 ° C. and a pressure of 6M.
Desulfurization was performed by passing oil along with hydrogen under the conditions of Pa, LHSV ¹ h ^-1 , and a hydrogen / oil ratio of 1000 scfb. The sulfur content of the first reactor produced oil was 0.041% by weight. The oil produced in the first reactor is further desulfurized in the second reactor under the same conditions as in Example 1,
Sulfur content 0.005% by weight, color is Saybolt color +2
No. 4 light oil was produced.

Example 3 Middle Eastern straight-run gas oil (boiling point: 224 to 368 ° C., sulfur content: 1.
41% by weight) and 80% by volume of catalytic cracking gas oil (boiling point 212
The mixture was mixed with 10% by volume (-345 ° C, 0.23% by weight of sulfur) and 10% by volume of directly decomposed gas oil (boiling point: 181-346 ° C, 0.08% by weight of sulfur). This mixed gas oil was desulfurized in a first reactor filled with the same amount of the same catalyst as in Example 1 by passing it along with hydrogen under the conditions of a temperature of 350 ° C., a pressure of 3 MPa, a LHSV of 2 h ⁻¹ , and a hydrogen / oil ratio of 1000 scfb. .
The sulfur content of the produced oil was 0.13% by weight. Further, as a second reactor, 90% by weight of amorphous silica alumina and proton exchange USY
Nickel 4 parts by weight of a carrier comprising a mold zeolite 10 wt% (NiO conversion) and tungsten 20 parts by weight (WO ₃ equivalent) supporting a catalyst and 200ml filling, the lower part γ
- Cobalt 5 parts by weight of alumina support (CoO conversion) and molybdenum 20 parts by weight of (MoO ₃ conversion) supporting a catalyst and 100ml filled. This catalyst was heated to 300 ° C. using straight-run kerosene containing dimethyl disulfide (3% by weight of sulfur).
12MPa, LHSV1h- ¹ , hydrogen / oil ratio 1000sc
After presulfurizing for 4 hours under the condition of fb, the desulfurized gas oil and hydrogen were heated at 350 ° C., pressure 12 MPa, LHSV
Desulfurization was performed by passing the oil under the conditions of ¹ h ^-1 and a hydrogen / oil ratio of 2000 scfb. A gas oil having a sulfur content of 0.005% by weight and a color of +20 in Saybolt color was produced.

Comparative Example 1 97% by weight of γ-alumina was added to the reaction tube used in Example 1.
3 parts by weight (in terms of NiO) of nickel and 3 parts by weight of molybdenum 20
The catalyst supporting 600 parts by weight (in terms of MoO ₃ ) was filled with 600 ml. 300 ° C., 5 MPa, LHSV 1 h using straight-run kerosene containing dimethyl disulfide (sulfur content: 3% by weight)
^{-1 under} a hydrogen / oil ratio of 1000 scfb for 4 hours,
After pre-sulfurization, the light oil used in Example 1 was heated to a temperature of 340.
Desulfurization was carried out by passing oil at a temperature of 10 ° C., a pressure of 10 MPa, an LHSV of 0.5 h ⁻¹ , and a hydrogen / oil ratio of 2000 scfb. The sulfur content of the produced oil was 0.024% by weight, and the color was -10 in Saybolt color.

Comparative Example 2 A γ-alumina carrier 100 was added to the reaction tube used in Example 1.
6 parts by weight of a catalyst supporting 5 parts by weight of cobalt (in terms of CoO) and 20 parts by weight of molybdenum (in terms of MoO ₃ ) per part by weight.
00 ml was filled. This catalyst was pre-sulfurized in the same manner as in Comparative Example 1, passed through the light oil of Example 1, and desulfurized under the same conditions as in Comparative Example 1. The sulfur content of the produced oil was 0.029% by weight,
The color was +15 in Saybolt color.

Comparative Example 3 The mixed gas oil of Example 3 was passed through the catalyst of Comparative Example 1 for hydrodesulfurization. The reaction conditions were a temperature of 360 ° C., a pressure of 10 MPa,
The LHSV is 0.5 h ^-1 and the hydrogen / oil ratio is 2000 scfb. The sulfur content of the produced oil was 0.013% by weight, and the color was -15 in Saybolt color.

Comparative Example 4 Desulfurization was carried out in the first reactor under the same starting oil, catalyst and reaction conditions as in Example 1. In a second reactor filled with the produced oil and the same catalyst as in Example 1, the produced oil in the first reactor was mixed with hydrogen at a temperature of 320 ° C., a pressure of 5 MPa, and an LHSV of 0.5.
The oil was passed under a condition of h ^-1 and a hydrogen / oil ratio of 2000 scfb to perform desulfurization. The sulfur content of the produced oil was 0.024% by weight, and the color was +10 in Saybolt color.

[0029]

According to the present invention, when performing hydrodesulfurization of a gas oil fraction of a sulfur-containing petroleum hydrocarbon, a low sulfur content (sulfur content 0.005% by weight or less) and a hue. Excellent light oil can be produced.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 4G069 AA03 AA15 BA01A BA01B BA07A BA07B BC59A BC59B BC67A BC67B BC68A BC68B CC02 DA06 EA18 EC22Y ZA05B 4H029 CA00 DA00 DA09

Claims (7)

[Claims] 1. A light oil having a sulfur content of 0.005% by weight or less and a Saybolt color +20 or more. 2. A light oil having a sulfur content of 0.001% by weight or less and a Saybolt color +20 or more. 3. When hydrodesulfurizing a gas oil fraction of a petroleum hydrocarbon containing sulfur, after hydrodesulfurization in a first step, hydrodesulfurization is performed in a second step at a higher pressure than in the first step. The method for hydrodesulfurization of gas oil. 4. The method according to claim 3, wherein the sulfur content of the feed oil is reduced to 0.05% by weight or less by the hydrodesulfurization in the first step, and then the hydrodesulfurization is further performed in the second step at a higher pressure than in the first step. Method of hydrodesulfurization of diesel oil. 5. The reaction condition of the first step is a temperature of 320 to 3
80 ° C., pressure 4 to 7 MPa, LHSV 0.5 to 3 h ⁻¹ ,
The hydrogen / oil ratio is 500-2000 scfb, and the reaction conditions in the second step are as follows: temperature 320-380 ° C., pressure 10-15.
MPa, LHSV 0.5-2h ^-1 , hydrogen / oil ratio 1000
The method for hydrodesulfurization of gas oil according to claim 3 or 4, wherein the amount is from 5000 scfb. 6. The catalyst used in the first step is a catalyst in which cobalt and molybdenum are supported on a porous carrier mainly composed of alumina, and the catalyst used at the entrance of the second step is 85 to 99% by weight of alumina. % Nickel and molybdenum on a porous carrier containing 1% to 15% by weight of zeolite and a ratio of 4 to the total catalyst in the second step.
The catalyst at the outlet of the second step is a catalyst in which cobalt or nickel and molybdenum are supported on a porous carrier mainly composed of alumina.
The method for hydrodesulfurization of light oil according to the above. 7. The hydrogen gas used in the second step has a hydrogen purity of 65% by volume or more and a hydrogen sulfide concentration of 0.05%.
The method for hydrodesulfurization of gas oil according to claim 3, which is not more than% by volume.