JPH093460A - Method for manufacturing gasoline base material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a gasoline base substantially without containing benzene from a crude benzene fraction. SOLUTION: This method for producing a gasoline base comprises a step for bringing a crude benzene fraction into contact with hydrogen under hydrogenating conditions of an existing catalyst containing a group VIII metal of the periodic table supported on an inert inorganic oxide and converting the benzene in the crude benzene fraction into cyclohexane and a step for selectively converting the cyclohexane in the hydrogenated product oil obtained in the step into methylcyclopentane under hydrogenating isomerization conditions of an existing catalyst containing the group VIII metal of the periodic table supported on zeolite, an acidic salt of a heteropoly acid, a ZrO2 containing sulfate radicals or TiO2 containing the sulfate radicals.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a benzene-free gasoline base material from a crude benzene fraction, more specifically, a method for selectively hydroisomerizing benzene in the crude benzene fraction. To produce a methylcyclopentane-rich gasoline base material.

[0002]

2. Description of the Related Art In recent years, there has been a movement to regulate the concentration of benzene contained in gasoline. For example, in California, the United States, from March 1996, California phase II gasoline is restricted to have a benzene concentration of 1.0 vol% or less. The main reason for gasoline containing benzene is the use of catalytic reforming oil (reformate) of naphtha as a gasoline base material. Most of the benzene contained in existing gasoline is derived from reformate. To do. Therefore, benzene-free gasoline can be easily produced by precisely distilling the reformate to remove benzene. And, the benzene fraction removed by this precision distillation usually contains hydrocarbons other than benzene, but these can be removed from benzene by solvent extraction, so benzene separated from reformate is a cyclohexane production raw material. Alternatively, it can be effectively used as a raw material for styrene production.
However, removing benzene from reformate by precision distillation inevitably reduces the amount of reformate that can be used as a gasoline base material. It is desirable to convert to hydrogen to allow reblending into gasoline.

As a method of converting benzene contained in a crude benzene fraction into another hydrocarbon, it is known to hydrogenate benzene to cyclohexane, but this method sacrifices a research octane number. Not recommended. Table 1 (Source: Journal of Japan Petroleum Institute, Vol. 14, No. 10, No. 84
Page 1 (1971) shows the octane numbers of C ₅ hydrocarbons and C ₆ hydrocarbons. In the case of cyclopentane, the decrease in octane number is only 6.7 points.

[Table 1] Research method Octane number Motor method Octane number Isopentane 92.3 90.3 n-Pentane 61.7 61.9 Cyclopentane 101.7 85.0 2,2-Dimethylbutane 91.8 93.4 2,3- Dimethylbutane 103.6 94.3 2-Methylpentane 73.4 73.5 3-Methylpentane 74.5 74.3 n-Hexane 24.8 26.0 Methylcyclopentane 91.3 80.0 Cyclohexane 83.0 77.2 Benzene 98.0 94.0 Therefore, when the benzene contained in the crude benzene fraction is converted into cyclohexane, it is possible to further convert the cyclohexane into methylcyclopentane. It is preferable because it does not decrease.

[0004]

DISCLOSURE OF THE INVENTION An object of the present invention is to hydrogenate benzene in a crude benzene fraction to convert it into cyclohexane, and then further selectively hydroisomerize cyclohexane into methylcyclopentane. The main object is to provide a method for producing a gasoline base material which does not substantially contain benzene.

[0005]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has contacted a crude benzene fraction with hydrogen to hydrogenate benzene contained in the crude benzene fraction to produce cyclohexane. After the conversion, it was found that a gasoline base material substantially free of benzene can be produced by contacting the obtained product with hydrogen again to selectively convert the cyclohexane contained in the product into methylcyclopentane. The present invention has been completed. Therefore, the method for producing a gasoline base material according to the present invention is (a) a hydrogenation catalyst comprising an inert inorganic oxide carrier and at least one active metal selected from Group VIII metals of the periodic table. In the presence of hydrogen, the crude benzene fraction is contacted with hydrogen to convert benzene in the crude benzene fraction to cyclohexane; and (b) at least one active metal selected from Group VIII metals of the periodic table, The step (a) is obtained in the presence of a hydroisomerization catalyst supported on at least one carrier selected from the group consisting of zeolite, acidic salt of heteropolyacid, sulfate-containing ZrO ₂ and sulfate-containing TiO _2. Contacting the product with hydrogen to selectively convert cyclohexane to methylcyclopentane.

In the present invention, a crude benzene fraction is used as a feedstock for gasoline base stocks. The crude benzene fraction preferably contains 10% by weight or more of benzene, more preferably 20%.
It means a hydrocarbon fraction containing at least wt%, particularly preferably 30 to 70 wt%, and the boiling point range of the fraction is preferably 2
The temperature is 5 to 200 ° C, more preferably 25 to 130 ° C.
A typical example of a crude benzene fraction is a benzene-containing fraction obtained by precision distillation of reformate known as a conventional gasoline base material. The amount of benzene contained in this fraction depends on the benzene content of reformate and / or precision distillation conditions, but is generally 30 wt.
It contains% or more benzene, the hydrocarbon components other than benzene, mainly containing straight-chain C ₆ and branched C ₆ hydrocarbons, which may C ₇ hydrocarbons contained in a trace amount. Further, as the feedstock of the present invention, it is also possible to use a pure benzene fraction containing almost no hydrocarbon other than benzene.

As the active metal of the hydrogenation catalyst used in the step (a) of the present invention, at least one metal component selected from Group VIII metals of the Periodic Table is, for example, platinum, palladium or nickel. , Rhodium, etc. are used. Above all,
Platinum, palladium and platinum-palladium are preferable, and platinum is particularly preferable. The amount of the active metal component supported is preferably 0.1 to 2.0 wt% in terms of metal, and more preferably 0.3.
˜1.5 wt%. An inert inorganic oxide is used for the carrier on which the active metal component is supported, and specifically, alumina, silica, silica-alumina, titania, boria, zirconia, or a mixture thereof is used. Of these, alumina, silica, and silica / alumina are preferably used. The reaction conditions in step (a) include:
Pressure 5 to 100 atm, preferably 10 to 50 atm, temperature 100 to 300 ° C., preferably 150 to 250 ° C., feed oil feed rate (LHSV) 1.0 to 50.0 h ⁻¹ , preferably 5.0 to 10.0 h ^-1 , a hydrogen / benzene molar ratio of 3.0 to 10.0, preferably 3.5 to 5.0 is selected. In the hydrogenation reaction of benzene in the step (a), when the concentration of benzene in the crude benzene is high, a large amount of heat may be generated due to the nuclear hydrogenation of benzene. In order to remove the heat of reaction, for example, in the step (a), a part of the hydrogenation product oil of this step is recycled to the feed oil, and the benzene concentration of the feed oil supplied to the inlet of the hydrogenation reaction column is adjusted to an appropriate concentration. , Preferably about 10 wt%.
Further, as a method for removing the heat of reaction, a method of introducing cold hydrogen from the middle stage of the reaction tower which is usually performed may be used together.

The cyclohexane-containing hydrocracked oil obtained in step (a) is then treated in step (b). The active metal of the catalyst used in this hydroisomerization step is the periodic table. At least one metal component selected from Group VIII metals such as platinum, palladium, nickel and rhodium is used. Among them, platinum, palladium,
Platinum-palladium is preferable, and platinum is particularly preferable. The supported amount of the active metal component is preferably 0.1 to 100 in terms of metal.
It is in the range of 2.0 wt%, more preferably 0.3 to 1.5 wt%. And, the carrier on which the active metal component is carried,
Zeolite, acid salt of heteropoly acid, sulfate (S
O ₄ ^{2 −} )-containing ZrO ₂ and sulfate (SO ₄ ^{2 −} )-containing Ti
At least one selected from the group consisting of O ₂ is used. As the zeolite, zeolite having a relatively strong acid point is preferable.
Type zeolite, X type zeolite, L type zeolite, pentasil type zeolite, Ω type zeolite, β type zeolite, mordenite, ferrierite, ZSM-5 and the like. Of these, Y-type zeolite is preferably used. The acid salt of a heteropoly acid is a salt of a heteropoly acid in which a part of hydrogen ions is replaced with another cation. Specific examples of the heteropolyacid include H ₃ PMo ₁₂ O ₄₀ and H ₃ PW.
₁₂ O _{40 and the} like can be exemplified, and specific examples of the cation are K ⁺ ,
Examples thereof include Rb ⁺ , Cs ⁺ , NH ₄ ^{+ and the} like. When an acidic salt of heteropolyacid is used as a carrier, a cesium-containing heteropoly compound (CS _2.5 H _0.5 PW ₁₂ O ₄₀ ) is preferably used. The sulfate group content of the zirconia carrier or the titania carrier containing the sulfate group is usually 0.1 in terms of sulfur.
It is in the range of 8 wt%, preferably 1 to 5 wt%.

The pressure condition of the step (b) is 10 to 100.
Atm, preferably 20 to 60 atm can be selected, but it is particularly preferred to select a pressure which is 2 to 5 atm lower than the pressure of step (a) for the purpose of saving processing costs. The reaction temperature is 200 to 360 ° C., preferably 260 to 340
Selected in the range of ℃, LHSV is 2.0 ~ 15.0
h ^-1, preferably selected in the range of 3.0~8.0h ^-1. The ratio of hydrogen / produced oil in step (a) is 1
0.0-150.0 NL / L oil, preferably 30.0-
It is selected in the range of 120.0 NL / L oil.

[0010]

EFFECTS OF THE INVENTION According to the present invention, benzene in the crude benzene fraction can be hydrogenated to cyclohexane and then hydroisomerized to methylcyclopentane.
It is possible to produce a gasoline base material having a research octane number higher than the research octane number as a whole of the crude benzene fraction and substantially not containing benzene.

[0011]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but these examples do not limit the technical scope of the present invention. Example 1 A crude benzene fraction having the composition shown in Table 2 was used as a feed oil,
First, a hydrogenation treatment of a crude benzene fraction was carried out under the reaction conditions of the step (a) shown in Table 2 by using a catalyst in which platinum was supported on platinum in an amount of 0.5 wt% in terms of metal. Next, a part of the hydrogenated product oil obtained in step (a) was recycled to the feed oil, and the other product oil was hydroisomerized under the reaction conditions of step (b) shown in Table 2. As the catalyst, a Y-type zeolite on which platinum was supported by 0.8 wt% in terms of metal was used. Table 2 shows the respective compositions, research octane numbers (C ₆ + RON) and C ₆ + yields of the hydrogenated product oil obtained in step (a) and the product oil obtained in step (b). In addition, the research method octane number (C ₆ + RON) in the table
Is calculated from the volume ratio of hydrocarbons having 6 or more carbon atoms and the research method octane number shown in Table 1 above. Further, since the C ₆ + yield involves some hydrocracking reaction in the above two steps, in order to evaluate the degree thereof, the ratio of the weight of the produced C ₆ hydrocarbons to the weight of the C ₆ hydrocarbons fed was determined by weight%. It is shown in.

[Table 2] As shown in Table 2, in step (a), substantially all of the benzene contained in the crude benzene fraction is converted to cyclohexane, but the product oil has a C ₆ + RON value of 57.8.
The value of C ₆ + RON of the crude benzene fraction is lower than 61.3. However, further hydroisomerization of this hydrotreated oil converts cyclohexane to methylcyclopentane without the formation of benzene, resulting in step (b)
The value of C ₆ + RON of the produced oil obtained in 1 is improved to 70.4. Example 2 The hydrotreated oil obtained in step (a) of Example 1 was hydroisomerized under the reaction conditions shown in the second column of Table 3. However, the catalyst used was one in which 0.5 wt% of platinum was supported on zirconia containing a sulfate group in terms of metal. The composition, C ₆ + RON and C ₆ + yield of the resulting product oil are shown in the second column of Table 3. As is clear from this, even in this hydroisomerization reaction, benzene is not produced as in the case of Example 1. And the amount of cyclohexane is 51.5 wt% of the hydrogenated oil
From 1 wt% to 15.4 wt%, the amount of methylcyclopentane increased from 0.6 wt% to 28.6 wt%, and the value of C ₆ + RON also improved from 57.8 to 75.8. Example 3 The hydrotreated oil obtained in step (a) of Example 1 was hydroisomerized under the reaction conditions shown in the third column of Table 3. However, as a catalyst, a cesium-containing heteropoly compound (Cs _2.5 H _0.5
PW ₁₂ O ₄₀ ), on which platinum was supported by 1.5 wt% in terms of metal, was used. Composition of the produced oil obtained, C ₆ + RON
And C ₆ + yields are shown in the third column of Table 3. As is clear from this, even in this hydroisomerization reaction, benzene is not produced as in the case of Example 1. Then, the amount of cyclohexane is reduced from 51.5 wt% of the hydrogenated oil to 8.0 wt%, and the amount of methylcyclopentane is 1.2 wt% to 29.0.
wt%, and the value of C ₆ + RON also increased from 57.8 to 72.1
Improve to. Example 4 The hydrotreated oil obtained in the step (a) of Example 1 was hydroisomerized under the reaction conditions shown in the fourth column of Table 3. However, as a catalyst, platinum was added to titania containing sulfate as a metal conversion factor of 0.1.
The one loaded with 5 wt% was used. The composition, C ₆ + RON and C ₆ + yield of the resulting product oil are shown in the fourth column of Table 3. As is clear from this, even in this hydroisomerization reaction, benzene is not produced as in the case of Example 1. And
The amount of cyclohexane is 51.5 wt% of hydrogenated oil to 1
5.4 wt% and the amount of methylcyclopentane is 0.6
Increased from wt% to 28.6 wt% and the value of C ₆ + RON was 5
Increased from 7.8 to 75.3.

[Table 3] Comparative Example 1 The hydrogenated oil obtained in step (a) of Example 1 was treated under the reaction conditions shown in the second column of Table 4. However, the catalyst used was a silica-alumina carrier on which platinum was supported by 0.8 wt% in terms of metal. Composition of the produced oil obtained, C ₆ + R
The ON and C ₆ + yields are shown in the second column of Table 4. As is clear from this, the cyclohexane in the hydrogenated oil used as a raw material can hardly be converted to methylcyclopentane by this treatment.

[Table 4] Comparative example 2 The hydrogenated oil obtained in step (a) of Example 1 is
The reaction was carried out under the reaction conditions shown in column 3. However, the catalyst is Y type
When 0.8 wt% of platinum was loaded on the zeolite
Was used. This processing condition is that LHSV is 20h.^-1To
Identical to that of step (b) of Example 1 except that it is increased
It is. The composition of the produced oil obtained, C₆+ RON and C₆+ Income
The rates are shown in the second column of Table 4. As is clear from this, L
HSV for 20h^-1Increased to methylcyclo
The amount of pentane produced was as small as 12.4 wt%, and C₆+ RON
The value of is as low as 60.7. Comparative Example 3 The hydrogenated oil obtained in step (a) of Example 1 is
The treatment was carried out under the reaction conditions shown in column 4. However, comparison with catalyst
The same catalyst as in Example 2 was used. This processing condition is the reaction pressure
That of step (b) of Example 1 except that the pressure was reduced to 9 atm
Is the same as The composition of the produced oil obtained, C₆+ RON and
C₆+ Yield is shown in the fourth column of Table 4. As is clear from this
Then, when the reaction pressure was lowered to 9 atm, cyclohexane
Since the dehydrogenation reaction occurs and benzene is produced,
To obtain a gasoline base material that is substantially free of
Yes.Comparative Example 4 The hydrogenated oil obtained in step (a) of Example 1 is
The reaction was carried out under the reaction conditions shown in column 5. However, comparison with catalyst
Using the same catalyst as in Example 2 but substituting nitrogen for hydrogen
Was. This processing condition is the same as that used in the step (b) of Example 1.
Instead of hydrogen supplied to the reaction system, use the same amount of nitrogen.
The process conditions are the same as those of the step (b) of Example 1 except that the treatment conditions are the same.
It is. The composition of the produced oil obtained, C₆+ RON and C₆+ Income
The rates are shown in the fifth column of Table 4. As you can see, water
If nitrogen is used instead of nitrogen, cyclohexane
Almost progressed hydroisomerization reaction to methylcyclopentane
Without it, benzene is produced.

Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C10G 45/48 9547-4H C10G 45/52 45/52 9547-4H 45/62 45/62 9547-4H 45 / 64 45/64 9547-4H 65/08 65/08 6958-4H C10L 1/06 C10L 1/06 B01J 23/74 321M

Claims (2)

[Claims] 1. A crude benzene fraction is prepared in the presence of a hydrogenation catalyst comprising: (a) at least one active metal selected from Group VIII metals of the Periodic Table on an inert inorganic oxide support. Converting the benzene in the crude benzene fraction into cyclohexane by contacting with hydrogen, and (b) Periodic Table VI
At least one active metal selected from Group II metals is selected from the group consisting of zeolite, acidic salts of heteropolyacids, sulfate-containing ZrO ₂
And cyclohexane is selected by contacting the product obtained in step (a) with hydrogen in the presence of a hydroisomerization catalyst supported on at least one carrier selected from the group consisting of and TiO ₂ containing sulfate radicals. A method for producing a gasoline base material, which comprises the step of converting it to methylcyclopentane. 2. The reaction condition of step (a) is a pressure of 5 to 100.
atm, temperature 100 to 300 ° C., LHSV 1.0 to 50.
0, the hydrogen / benzene molar ratio is in the range of 3.0 to 10.0, the reaction conditions of step (b) are pressure of 10 to 100 atm,
The method according to claim 1, wherein the temperature is 150 to 360 ° C., the LHSV is 2.0 to 15.0, and the hydrogen / feed oil ratio (NL / L) is in the range of 10.0 to 150.0.