JP3269900B2 - Desulfurization of cracked gasoline fraction - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for desulfurizing a cracked gasoline fraction containing a sulfur compound and an olefin component without reducing the olefin component content as much as possible.

[0002]

2. Description of the Related Art In the field of petroleum refining, gasoline sources containing a large amount of olefin components include a catalytic cracking gasoline fraction obtained from a catalytic cracking step and a pyrolysis gasoline fraction obtained from a thermal cracking step. The former is a gasoline fraction obtained by catalytic cracking of a heavy petroleum fraction, for example, a feed oil such as vacuum gas oil or atmospheric residual oil, and recovering and distilling a catalytic cracking product. It is fractionated into a catalytic cracking gasoline fraction and is used as one of the major admixture sources for automotive gasoline. Further, the latter is a gasoline fraction obtained by pyrolyzing a heavy oil fraction, for example, a raw oil such as a vacuum resid and collecting and distilling an oily pyrolysis product excluding coke and gas. Is fractionated into light and heavy pyrolysis gasoline fractions and is used as one of the sources of admixture in automotive gasoline.

[0003] However, both the catalytic cracking feedstock and the thermal cracking feedstock originally have a relatively high content of sulfur compounds, and if this is subjected to catalytic cracking or thermal cracking as it is, the catalytic cracking product And the sulfur compound content of the thermal decomposition products also increases. In particular, the heavy catalytic cracking gasoline fraction and the heavy pyrolysis gasoline fraction are one of the fractions in which sulfur compounds are easily concentrated, and if they are used as a mixture source for automobile gasoline, the impact on the environment will be a problem. Might be. For this reason, the raw material oil is often subjected to a desulfurization treatment before the catalytic cracking treatment or the thermal cracking treatment.

On the other hand, the naphtha fraction obtained by distilling crude oil is generally subjected to catalytic reforming, at least a part of which is converted to aromatic to increase the octane number. The naphtha fraction of the raw material to be catalytically reformed must also be desulfurized before catalytic reforming.

[0005] With regard to the desulfurization, one of the methods conventionally used in the field of petroleum refining is hydrodesulfurization, which is carried out in a high-temperature and pressurized hydrogen atmosphere.
The feedstock oil to be desulfurized is brought into contact with a suitable hydrodesulfurization treatment catalyst. A typical hydrodesulfurization catalyst for hydrodesulfurization of heavy petroleum fractions, such as vacuum gas oil or atmospheric residual oil, which is the raw material for catalytic cracking, or vacuum residual oil, which is the raw material for thermal cracking Is a combination of Group VIII and VI elements, such as cobalt and molybdenum, on a suitable substrate, such as alumina. The conditions for the hydrodesulfurization treatment are generally as follows: a temperature of about 350 to 450 ° C.
Hydrogen partial pressure about 100-200 kg / cm ² G, liquid space velocity (L
HSV) of about 0.1 to 21 / hr.

[0006] On the other hand, in the case of the hydrodesulfurization treatment of a naphtha fraction, a typical hydrodesulfurization treatment catalyst is obtained by combining Group VIII and Group VI elements such as cobalt and molybdenum on a suitable base material such as alumina. It is a thing. In general, the conditions for the hydrodesulfurization treatment are as follows.
80-350 ° C., hydrogen partial pressure of about 15-40 kg / cm ² G, and liquid hourly space velocity (LHSV) of about 2-81 / hr are employed.

[0007]

However, hydrogen of a heavy petroleum fraction such as vacuum gas oil or atmospheric residual oil which is a raw material for catalytic cracking, or a vacuum residual oil which is a raw material for thermal cracking, etc. In the case of chemical desulfurization, the processing conditions are high temperature and high pressure as described above, so the design conditions of the equipment become severe, and the construction cost is high when additional equipment is installed to cope with the shortage of equipment capacity. There is.

On the other hand, when the catalytically cracked gasoline fraction or the thermally cracked gasoline fraction is subjected to hydrodesulfurization treatment under the above treatment conditions, the olefin component contained in these cracked gasoline fractions is hydrogenated, and the content thereof is reduced. Octane number of the cracked gasoline fraction is reduced. For this reason, after the hydrodesulfurization treatment, the material must be reformed to a high octane number material source in a catalytic reforming step or an isomerization step. That is, two processing steps are required.

An object of the present invention is to provide a method for hydrodesulfurizing a cracked gasoline fraction containing an olefin component, which is a high octane component, while minimizing the decrease in the olefin component.

[0010]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have tried to reduce the amount of olefin components as much as possible and to remove the sulfur compound content to an acceptable level. As a result of intensive studies on the conditions of the hydrotreating treatment, the inventors have completed a desulfurization treatment method for cracked gasoline fraction, which has a desulfurization rate of 50% or more and a reduction rate of olefin components of 50% or less.

That is, the present invention provides that a cracked gasoline fraction containing a sulfur compound and an olefin component is treated at a temperature of about 200-200 in the presence of a hydrodesulfurization treatment catalyst containing a desulfurization active metal and having its surface modified with carbon. 300 ° C, hydrogen partial pressure about 15-30 kg / cm ² G, liquid hourly space velocity (LHSV) about 9
~ 20 1 / hr or temperature about 300 ~ 400
° C, hydrogen partial pressure about 1-14 kg / cm ² G, liquid space tower speed (L
(HSV) is a method for desulfurizing a cracked gasoline fraction, which is brought into contact with hydrogen under conditions of about 3 to 30 1 / hr.

The present invention is an excellent gasoline material source by minimizing the reduction of the olefin component in a cracked gasoline fraction, without losing the usefulness of the cracked gasoline fraction which is a high octane number gasoline material source. The hydrodesulfurization treatment is particularly useful in that it can be performed in a single step using a single carbon-modified catalyst under relatively mild processing conditions.

The cracked gasoline fraction used in the present invention is obtained by catalytic cracking of a heavy petroleum fraction, for example, vacuum gas oil or atmospheric residual oil, and most of it is converted into a wide range of petroleum fractions. Thermal cracking of light catalytic cracking gasoline fraction, heavy catalytic cracking gasoline fraction and total catalytic cracking gasoline fraction obtained by recovering and distilling cracked products, and heavy petroleum fractions such as vacuum residue Most of this is converted to a wide range of petroleum fractions and coke, and light pyrolysis gasoline fractions obtained by recovering and distilling oily pyrolysis products other than gas and coke, and heavy heat Cracked gasoline fraction and total pyrolysis gasoline fraction.

That is, a light cracked gasoline fraction having a boiling range of about 30 ° C. to about 100 ° C.,
Preferably, a total cracked gasoline cut with a boiling range from about 30 ° C to about 220 ° C, more preferably from about 80 ° C to about 2 ° C.
It is a heavy cracked gasoline fraction with a boiling range up to 20 ° C.
The reason is that, among the cracked gasoline fractions, the fraction having a relatively high boiling point range has a large sulfur compound content as described, and is easy to desulfurize. On the other hand, the fraction having a relatively low boiling point has a low sulfur compound content, so that it is difficult to desulfurize, and in some cases, it may be difficult to achieve a target of a desulfurization rate of about 50% or more. In this sense, the most preferable raw material to be desulfurized is a heavy catalytic cracking gasoline fraction obtained by catalytic cracking of a raw material oil which is heavier than vacuum gas oil or the like.

The hydrodesulfurization treatment conditions applied to the method of the present invention include a temperature of about 200 to 300 ° C. and a hydrogen partial pressure of about 15 to 30.
kg / cm ² G, liquid hourly space velocity (LHSV) about 9 to 201 / hr
Alternatively, a temperature of about 300 to 400 ° C. and a hydrogen partial pressure of about 1
~ 14 kg / cm ² G, liquid hourly space velocity (LHSV) about 3 ~ 30
1 / hr, preferably at a temperature of about 200 to 300 ° C., a hydrogen partial pressure of about 15 to 30 kg / cm ² G, and a liquid hourly space velocity (LHS).
V) About 10-201 / hr, or about 300-4
The temperature is 00 ° C., the hydrogen partial pressure is about 1 to 10 kg / cm ² G, and the liquid hourly space velocity (LHSV) is about 3 to 301 / hr.

When the hydrodesulfurization temperature is lower than about 200 ° C., it is difficult to achieve the target of the desulfurization rate of about 50% or more. Conversely, when the hydrodesulfurization treatment temperature exceeds about 400 ° C., it is difficult to achieve the target of the reduction rate of the olefin component content of about 50% or less. be gas components in the decomposition reaction, C ₅ fraction more liquid yields decrease.

The hydrodesulfurization treatment pressure is about 1 to 30 kg / cm
² G, preferably in the range of about 1-25 kg / cm ² G.
If the hydrodesulfurization pressure is lower than about 1 kg / cm ² G, there is a possibility that the life of the catalyst will be adversely affected. Also, about 30 k
If it exceeds g / cm ² G, the target of the desulfurization rate of about 50% or more can be achieved, but it is difficult to achieve the target of the olefin component content reduction rate of about 50% or less. The liquid hourly space velocity (LHSV) of hydrodesulfurization treatment is about 3 ~
It is in the range of 301 / hr, preferably about 5 to 201 / hr. The hydrogen / oil ratio is between about 20 and about 20 commonly used in petroleum hydrorefining.
200Nm ³ / m ^3, preferably can be applied in the range of about 50~150Nm ³ / m ^3.

As for the catalyst, generally, a hydrodesulfurization catalyst generally used in the field of petroleum refining, in which a desulfurization active metal is supported on a porous inorganic oxide carrier, is used before a known hydrodesulfurization catalyst is used for hydrotreating. When presulfurized by the method and used,
High desulfurization activity and hydrogenation activity of olefin components. However, when this catalyst is used for the desulfurization treatment of a cracked gasoline fraction containing a sulfur compound and an olefin component, the desulfurization rate is high, but the decrease rate of the olefin component content is also high.

The catalyst used in the method of the present invention is a catalyst in which a desulfurization active metal is supported on a porous inorganic oxide carrier and the surface of the catalyst is modified with carbon.
It is effective to use a catalyst containing up to 30% by weight of carbon. Thereby, it becomes easy to suppress the reduction rate of the olefin component content as much as possible and to remove the sulfur compound content to an acceptable level.
As a method of modifying the surface of the hydrotreating catalyst with carbon, it is possible to forcibly modify the surface in a short time after preliminary sulfurization by a known method, but it is preferable to gradually modify the surface over a long time. Alternatively, an extraction catalyst commonly used for petroleum hydrorefining can be effectively used as a practical method.

The amount of carbon contained on the surface of the catalyst is about 2 to 30% by weight, preferably about 4 to 20% by weight. The amount of carbon contained on the catalyst surface is about 30
If the content is more than 10% by weight, the desulfurization activity is extremely reduced, and it is difficult to achieve the target of the desulfurization rate of about 50% or more. If the carbon content is less than about 2% by weight, the desulfurization rate is about 5%.
It is easy to achieve the target of 0% or more, but it is difficult to suppress the reduction rate of the olefin component content to about 50% or less.

Examples of the porous inorganic oxide carrier of the catalyst include alumina, silica, titania, magnesia and the like, and these can be used alone or in the form of a mixture. Preferably, alumina or silica-alumina is selected. Examples of the desulfurization active metal include chromium, molybdenum, tungsten, cobalt, and nickel, and these can be used alone or in the form of a mixture. Preferably, cobalt-molybdenum or nickel-cobalt-molybdenum is selected. These metals can be present on the support in the form of metals, oxides, sulfides or mixtures thereof. A known method such as an impregnation method or a coprecipitation method can be used as a method for supporting the active metal.

In the present invention, it is preferable to use a catalyst in which an active metal such as cobalt-molybdenum or nickel-cobalt-molybdenum is supported on an alumina carrier. The loading amount of the active metal is preferably about 1 to 30% by weight as an oxide, and particularly preferably about 3 to 20% by weight.

The type of the hydrotreating reaction tower may be any of a fixed bed, a fluidized bed and a boiling bed, but a fixed bed is particularly preferable. The contact between the catalytic cracking gasoline fraction and the catalyst is co-current upward flow,
Either cocurrent downflow or countercurrent may be employed. These individual operations are known in the field of petroleum refining and can be arbitrarily selected and performed.

[0024]

EXAMPLES The present invention will be described in more detail with reference to Examples. (Example-1) As a catalytic cracking gasoline fraction as a feedstock, a heavy catalytic cracking gasoline fraction obtained by catalytic cracking of a feedstock oil containing normal pressure residual oil was used. The properties are shown in Table 1. 5% by weight of alumina carrier for hydrodesulfurization catalyst
A commercially available catalyst supporting CoO and 17% by weight of MoO ₃ was preliminarily sulfurized by a known method, and a catalyst in which a reduced pressure gas oil fraction or a gas oil fraction was used under ordinary hydrodesulfurization treatment conditions for 2 years was used. The amount of carbon contained on the catalyst surface of the catalyst is 7% by weight. Hydrodesulfurization treatment conditions are reaction temperature 300 ° C,
Hydrogen partial pressure 5 kg / cm ² G, liquid hourly space velocity (LHSV) 51 / h
r, the hydrogen / oil ratio was 85 Nm ³ / m ³ . As a result, the desulfurization rate of the feedstock was 93% and the reduction rate of the olefin component was 10%.
%Met. Table 2 shows the results.

Example 2 The same feedstock and the same hydrodesulfurization catalyst as in Example 1 were used. The processing conditions were a reaction temperature of 350 ° C., and the other processing conditions were the same as in Example 1. Under the same conditions, a hydrodesulfurization treatment experiment was performed. As a result, the desulfurization rate of the feedstock was 98%, and the reduction rate of the olefin component was 37%. The results are also shown in Table 2.

Example 3 Using the same feedstock and the same hydrodesulfurization catalyst as used in Example 1, a reaction temperature of 3
50 ° C, hydrogen partial pressure 5 kg / cm ² G, liquid hourly space velocity (LHS
V) A hydrodesulfurization experiment was performed under the treatment conditions of 10 1 / hr and a hydrogen / oil ratio of 85 Nm ³ / m ³ . As a result, the desulfurization rate of the feedstock was 89% and the reduction rate of the olefin component was 11%.
Met. The results are also shown in Table 2.

Example 4 Using the same feedstock and the same hydrodesulfurization catalyst as used in Example 1, a reaction temperature of 3
50 ° C, hydrogen partial pressure 1 kg / cm ² G, liquid hourly space velocity (LHS
V) Under the processing conditions of 51 / hr and a hydrogen / oil ratio of 85 Nm ³ / m ³ ,
A hydrodesulfurization treatment experiment was performed. As a result, the desulfurization rate of the feedstock was 78%, and the reduction rate of the olefin component was 5%. The results are also shown in Table 2.

Example 5 Using the same feedstock and the same hydrodesulfurization catalyst as used in Example 1, a reaction temperature of 2
50 ° C, hydrogen partial pressure 25 kg / cm ² G, liquid hourly space velocity (LHS
V) A hydrodesulfurization treatment experiment was performed under a treatment condition of 10 1 / hr and a hydrogen / oil ratio of 85 Nm ³ / m ³ . As a result, the desulfurization rate of the feedstock was 62%, and the reduction rate of the olefin component was 11%. The results are also shown in Table 2.

(Comparative Example 1) A commercially available catalyst using the same feedstock as in Example 1 and having 5% by weight of CoO and 17% by weight of MoO ₃ supported on an alumina carrier was known as a hydrodesulfurization treatment catalyst. Presulfurized by the method described above and used without carbon modification. Hydrodesulfurization conditions are reaction temperature 3
00 ° C, hydrogen partial pressure 30 kg / cm ₂ G, liquid hourly space velocity (LHS
V) 31 / hr, hydrogen / oil ratio 100 Nm ³ / m ³ . As a result, the feedstock had a desulfurization rate of 98%, and the feedstock had an olefin reduction rate of 89%. Table 3 shows the results.

Comparative Example 2 Using the same feedstock and the same hydrodesulfurization treatment catalyst as in Comparative Example 1, the reaction conditions were a reaction temperature of 340 ° C., and otherwise the same conditions as in Comparative Example 1. Then, a hydrodesulfurization treatment experiment was performed. As a result, the feedstock had a desulfurization rate of 100% and the feedstock had an olefin reduction rate of 100%. The results are also shown in Table 3.

[0031]

According to the present invention using a hydrodesulfurization treatment catalyst whose surface has been modified with carbon and combining this with appropriate hydrodesulfurization treatment conditions, the cracked gasoline fraction as a feedstock can be obtained in a one-stage treatment. An excellent effect is obtained in that the reduction rate of the olefin component content can be suppressed to about 50% or less, and the desulfurization rate can be at least about 50%. Further, according to the present invention, a clean high octane gasoline fuel which is low in sulfur, has a lower aromatic content than reformed gasoline, and meets the demands of an increasingly environmentally friendly era. Can be easily manufactured.

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

Continuation of the front page (56) References JP-A-55-155090 (JP, A) JP-A-55-47145 (JP, A) JP-A-54-88903 (JP, A) JP-A-54-139607 (JP, A) JP-A-52-107008 (JP, A) JP-A-54-85204 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C10G 45/04 B01J 23/85 C10G 45/06 C10G 45/08 C10G 45/12

Claims (5)

(57) [Claims] 1. A cracked gasoline fraction containing a sulfur compound and an olefin component, wherein the porous carrier contains at least one or more types of desulfurizing active metals selected from the group consisting of chromium, molybdenum, tungsten, cobalt and nickel, In addition, in the presence of a hydrodesulfurization treatment catalyst whose surface is modified with carbon, a temperature of about 200 to 300 ° C., a hydrogen partial pressure of about 15 to 30 kg / cm ² G, and a liquid hourly space velocity (LHSV) of about 9
~ 201 / hr, or about 300 ~ 400
° C, hydrogen partial pressure about 1-14 kg / cm ² G, liquid space velocity (LH
SV) A method for desulfurizing a cracked gasoline fraction, which is brought into contact with hydrogen under conditions of about 3 to 30 1 / hr. 2. The cracked gasoline fraction is from about 30 ° C. to about 22 ° C.
The desulfurization process according to claim 1, comprising a total cracked gasoline fraction having a boiling point range up to 0 ° C. 3. The cracked gasoline fraction is from about 80 ° C. to about 22 ° C.
2. The desulfurization treatment method according to claim 1, comprising a heavy cracked gasoline fraction having a boiling point up to 0 ° C. 4. The conditions for hydrodesulfurization treatment are as follows:
300 ° C., hydrogen partial pressure about 15-30 kg / cm ² G, liquid hourly space velocity (LHSV) about 10-201 / hr, or temperature about 3
2. The desulfurization treatment method according to claim 1, wherein the temperature is any one of 00 to 400 ° C., a hydrogen partial pressure of about 1 to 10 kg / cm ² G, and a liquid hourly space velocity (LHSV) of about 3 to 30 1 / hr. 5. The hydrodesulfurization treatment catalyst, wherein the porous carrier contains at least one selected from the group consisting of chromium, molybdenum, tungsten, cobalt and nickel, and about 2 to 30% by weight of the catalyst surface. The desulfurization treatment method according to claim 1, comprising carbon.