JP2003277769A - Hydrocarbon isomerization method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for isomerizing a hydrocarbon containing a saturated hydrocarbon having 7 and 8 carbon atoms (so-called heavy naphtha). A reaction temperature of 130 to 160 in the presence of hydrogen.
A catalyst in which a hydrocarbon containing 50% by weight or more of a saturated hydrocarbon having 7 or 8 carbon atoms is contacted with a solid acid catalyst in which a sulfuric acid component and a platinum group metal component are supported on a carrier containing a zirconia portion and an alumina portion at a temperature of ℃. It is. Preferably, a solid acid catalyst is used in which the zirconia portion contains tetragonal zirconia, the alumina portion contains γ-alumina, and the platinum group metal component is crystallized.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to C7 and C8.
Of saturated hydrocarbons, in particular, linear saturated hydrocarbons, are converted into branched saturated hydrocarbons having the same carbon number.

[0002]

2. Description of the Related Art A liquid fuel for a spark ignition type internal combustion engine, so-called gasoline, usually contains a petroleum fraction obtained by distilling crude oil, and a gasoline base material obtained by treating such a petroleum fraction. Is being manufactured. The carbon number of the hydrocarbon contained in gasoline is usually about 4 to 10.

The octane number is a typical performance index of gasoline. As a base material showing a high octane number as a hydrocarbon having 7 or more carbon atoms, there are 7 to 9 carbon atoms such as toluene.
The reformed gasoline base material (reformate) containing the aromatic hydrocarbon as a main component is used.

An isomerization step is known as a method for producing a base material having a high octane number in a hydrocarbon having 5 or 6 carbon atoms. This is because linear saturated hydrocarbons have a low octane number, while branched saturated hydrocarbons with the same number of carbons show a high octane number, so linear saturated hydrocarbons are isomerized to branched saturated hydrocarbons to increase the octane number. It is a thing.

The present applicant is researching and developing an alumina / zirconia solid acid catalyst as a catalyst used in such an isomerization process. This catalyst is molded by including an alumina portion and a zirconia portion as disclosed in International Patent Publication WO98 / 09727 and the like. Since this catalyst is molded, it can be applied to a reaction device, which was difficult with a powdery zirconia-based solid acid catalyst, and can be easily applied when the catalyst is regenerated and used. Furthermore, the catalytic activity of the alumina / zirconia-based solid acid catalyst is higher than that of the powdery zirconia-based solid acid catalyst.

[0006]

When it is required to reduce the amount of aromatic hydrocarbons in gasoline as an environmental measure, the blending amount of the reformed gasoline base material is reduced, which is more than that of aromatic hydrocarbons. Since the saturated aliphatic hydrocarbon has a low octane number, the octane number of the hydrocarbon having 7 or more carbon atoms is lowered. As one of methods for compensating for the decrease in octane number, isomerization of linear saturated hydrocarbons, which occupy most of saturated aliphatic hydrocarbons, into branched saturated hydrocarbons has been studied. The present invention proposes a method for isomerizing hydrocarbons containing saturated hydrocarbons having 7 and 8 carbon atoms (so-called heavy naphtha).

[0007]

Means for Solving the Problems The present inventors have found that when a specific isomerization catalyst is used, the composition of the raw material is limited and the reaction is carried out within a specific temperature range, whereby the isomerization is efficiently carried out. And completed the present invention. The hydrocarbon isomerization method according to the present invention is carried out at a reaction temperature of 130 to 1 in the presence of hydrogen.
At 60 ° C., a hydrocarbon containing 50% by weight or more of a saturated hydrocarbon having 7 and 8 carbon atoms is brought into contact with a solid acid catalyst having a sulfuric acid component and a platinum group metal component supported on a carrier containing a zirconia portion and an alumina portion. It is a thing. It is preferable to use a solid acid catalyst in which the zirconia portion contains tetragonal zirconia, the alumina portion contains γ-alumina, and the platinum group metal component is crystallized.

It is preferable that the total water content of the hydrocarbon and hydrogen used in the isomerization reaction is 15 ppm or less, and that the isomerization reaction is carried out under a pressure of 1.5 to 10 MPa. Further, the reaction product obtained by this hydrocarbon isomerization method is separated into a fraction mainly containing branched hydrocarbons and a fraction mainly containing straight chain hydrocarbons, and the straight chain hydrocarbons are mainly separated. Further isomerization can be carried out using the fraction containing the starting material.

[0009]

When the reactivity of the specific catalyst used in the present invention was examined, it was found that when a hydrocarbon containing 6 or less carbon atoms and 7 or 8 carbon atoms was isomerized using this catalyst,
It was found that those having 6 or less carbon atoms are selectively isomerized and those having 7 or more carbon atoms hardly react. The present inventors have found that in such a reaction, a cation having 3 or less carbon atoms, which is generated when a branched hydrocarbon having 6 carbon atoms is decomposed, is unstable.
It was considered that the isobutyl cation generated when the branched hydrocarbon having 7 or 8 carbon atoms was decomposed was stable, and that the carbon atom having 7 or more carbon atoms was easily decomposed.

Therefore, it is thought that by separating hydrocarbons containing 7 and 8 carbon atoms and using this catalyst to carry out the reaction at a relatively low temperature, isomerization is possible without decomposition. Then, the present invention has been completed. According to the present invention, saturated hydrocarbons having 7 and 8 carbon atoms can be used as a base material having a high octane number in a high yield, whereby aroma in gasoline can be obtained without deteriorating the operating performance of the gasoline engine. Family members can be reduced.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION [Solid Acid Catalyst] A carrier for a solid acid catalyst is a zirconia portion in which at least a part of the metal oxide is zirconium, and an alumina in which at least a part of the metal oxide is aluminum. Including parts. It is preferable that zirconium oxide is contained in the catalyst in an amount of 20 to 72% by weight, particularly 30 to 60% by weight, as zirconium element weight. Further, it is preferable that the catalyst contains aluminum oxide in an amount of 5 to 30% by weight, particularly 8 to 25% by weight, as an aluminum element weight. The metal oxide is defined to include a hydrous metal oxide.
Zirconia portion, alumina portion, other metal components, such as boron, magnesium, aluminum, silicon,
Phosphorus, calcium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, germanium, yttrium, zirconium, niobium, molybdenum, tin, hafnium, tungsten, lanthanum,
Cerium or the like may be contained alone, as a mixture, or as a composite metal oxide such as zeolite.

The zirconia portion preferably consists essentially of tetragonal zirconia. This can be confirmed by powder X-ray diffraction, and specifically, 2θ = 3 by CuKα ray.
It can be confirmed by the diffraction peak of tetragonal zirconia at 0.2 °. It is preferably crystallized to the extent that it can be confirmed by a diffraction peak, and monoclinic zirconia is preferably not contained. 2θ =
Diffraction peak area of tetragonal zirconia at 30.2 ° (S3
0) and the diffraction peak area (S28) of monoclinic zirconia with 2θ = 28.2 ° (S28 / S30) of 1.0 or less, particularly preferably 0.05 or less. Further, the alumina portion is crystallized, and it is particularly preferable that it substantially consists of γ-alumina.

The solid acid catalyst contains a sulfuric acid content. The proportion of sulfuric acid (SO ₄ ) in the catalyst is 0.7 to 7% by weight, preferably 1 to 6% by weight, and particularly 2 to 5% by weight, as the weight of elemental sulfur. If the sulfuric acid content is too large or too small, the catalytic activity will decrease. Further, halogen may be contained if necessary to improve the acid catalyst performance.

The solid acid catalyst contains at least one metal selected from platinum group metals. Examples of the platinum group metal here include platinum, palladium, ruthenium, rhodium, iridium, and osmium. Platinum, palladium and ruthenium are preferable, and platinum is particularly preferable. The ratio of the platinum group metal component in the catalyst (average value of platinum group metal component concentration) was 0.01 as the weight of the metal element.
10 to 10% by weight, particularly 0.05 to 5% by weight, and further preferably 0.1 to 2% by weight. When the content of the platinum group metal component is too small, the catalyst performance improving effect is low, which is not preferable. When the content of the platinum group metal component is too large, the specific surface area and the pore volume of the catalyst decrease, which is not preferable.

The crystallite diameter of the platinum group metal measured by X-ray diffraction is preferably 10 nm or less, particularly preferably 1 to 10 nm. When the content of the platinum group metal component is 0.15% by weight or more, particularly 0.2% by weight or more, and further 0.3% by weight or more, the platinum group metal concentration tends to be uniform.

The platinum group metal component is preferably crystallized. This can be confirmed by a clear diffraction peak of the platinum group metal by powder X-ray diffraction, and specifically, when the area of the diffraction peak by the sufficiently crystallized platinum group metal is 100%, it is 30 at the same position. It is preferable to exhibit a peak with an area of not less than%, especially 50% or more.

The preferred specific surface area of the solid acid catalyst is 50 to 50.
500m ² / g, especially 100 to 300 m ² / g, even at 140~200m ² / g. The specific surface area can be measured by the generally known BET method. The pore structure of the solid acid catalyst can be measured by the nitrogen adsorption method in the range of pore diameters of 0.002 to 0.05 μm and by the mercury intrusion method in the range of pore diameters of 0.05 to 10 μm. Pore diameter 0.00
The pore volume of 2~10μm is, 0.2 cm ³ / g or more, and particularly 0.3 cm ³ / g or more, further 0.35 cm ³ /
g-1.0 cm < ³ > / g is preferable.

Preferably, the solid acid catalyst is not in the form of powder, but in a molded form, so-called pellet form, in the range of 0.5-2.
The size of 0 mm can be easily obtained,
As an average particle size, 0.5 to 20 mm, especially 0.6 to 5
mm is preferably used. The mechanical strength of the catalyst is 2 kg as the side crush strength of a cylindrical pellet with a diameter of 1.5 mm.
Or more, more preferably 3 kg or more, still more preferably 4
~ 8 kg.

[Catalyst Production Method] The production method of the solid acid catalyst is not particularly limited, but as an example, a powder (hereinafter, referred to as “precursor powder”) which is a precursor of the metal oxide constituting the carrier is used. A manufacturing method is used in which a sulfur-containing compound is added to powder of a certain hydrous metal oxide and / or metal hydroxide, kneaded, molded, and fired to prepare a carrier, and a platinum group metal is supported on the carrier. . The method will be described below according to this method, but the order of forming and firing the carrier, supporting the sulfuric acid component, supporting the platinum group metal, and the like can be changed.

[Precursor powder] The precursor powder is a metal oxide that constitutes a carrier by firing after molding,
Although it may be produced by any method, it can be generally obtained by neutralizing or hydrolyzing a metal salt or an organometallic compound, washing and drying. Zirconium hydroxide (including hydrated oxide) is preferably used for the zirconia portion of the carrier, and boehmite is preferably used for the alumina portion. Further, the precursor powder may use a composite metal hydroxide and / or a composite metal hydrated oxide.

[Sulfur Content-Containing Compound] The sulfur content-containing compound is a compound containing a sulfuric acid content or a compound containing a sulfur content which can be converted into a sulfuric acid content by a subsequent treatment such as firing. Examples of the sulfur-containing compound include sulfuric acid, ammonium sulfate, sulfurous acid, ammonium sulfite, thionyl chloride, and dimethylsulfate, but sulfuric acid-containing compounds containing sulfuric acid are preferably used, and ammonium sulfate and dimethylsulfate are corrosion of manufacturing equipment. It is also preferred because it has low properties.
Particularly, ammonium sulfate is most preferably used.

The sulfur-containing compound may be used as it is or as a solution such as an aqueous solution. The sulfur-containing compound is not particularly limited in solid state, liquid state, or solution concentration, and can be prepared in consideration of the amount of solution necessary for kneading. The amount of the sulfur-containing compound added is such that the sulfuric acid content (S
It is preferable that the amount of O ₄ ) is 0.7 to 7% by weight, preferably 1 to 6% by weight, and particularly preferably 2 to 5% by weight, as the weight of elemental sulfur.

[Kneading] The kneading method is not particularly limited,
A kneader generally used for catalyst preparation can be used. Usually, a method in which raw materials are added, water is added and mixed with a stirring blade is preferably used, but the order of adding the raw materials and additives is not particularly limited. Water is usually added during kneading, but the liquid to be added may be an organic solvent such as ethanol, isopropanol, acetone, methyl ethyl ketone, or methyl isobutyl ketone. The temperature and the kneading time during the kneading are the hydrous metal oxide and / or the raw material.
Alternatively, although it depends on the precursor powder of the metal hydroxide and the sulfur-containing compound, the condition is not particularly limited as long as a preferable pore structure is obtained. Similarly, if the catalytic property of the present invention is within a range that can be maintained, an acid such as nitric acid or a base such as ammonia, an organic compound, a metal salt, a ceramic fiber, a surfactant, zeolite, clay, etc. are added and kneaded. I don't mind.

[Molding] The molding method after kneading is not particularly limited, and a molding method generally used for catalyst preparation can be used. In particular, extrusion molding using a screw extruder or the like is preferably used because it can be efficiently molded into an arbitrary shape such as a pellet shape or a honeycomb shape. The size of the molded product is not particularly limited, but it is usually molded to have a cross-sectional length of 0.5 to 20 mm. For example, cylindrical pellets having a diameter of 0.5 to 10 mm and a length of 0.5 to 15 mm can be easily obtained.

[Baking After Molding] The baking after molding is carried out in a gas atmosphere such as air or nitrogen, but it is particularly preferably carried out in air. The firing temperature is the firing time,
The temperature is generally 400 to 900 ° C., preferably 500 to 800 ° C., though it varies depending on other firing conditions such as gas flow rate. Although the firing time varies depending on other firing conditions such as firing temperature and gas flow rate, it is generally 0.05 to 20 hours, particularly 0.1 to 10 hours, and more preferably 0.2 to 5 hours.

[Support of Platinum Group Metal] The platinum group metal can be supported on the calcined carrier by preparing a carrier liquid containing the platinum group metal and impregnating the carrier. The carrier liquid contains a platinum group metal as a cation ion,
It is particularly preferable to include an ammine complex of a platinum group metal. As such an ammine complex, dichlorotetraammine platinum, tetrachlorohexaammine platinum or the like can be used. The metal component selected as the platinum group metal component is preferably platinum, palladium, ruthenium or the like, and platinum is particularly preferably used. Further, the platinum group metal component may contain a metal component of another group. The addition amount of these metal compounds is such that the total amount of platinum group metal components in the solid acid catalyst is 0.01 to 10% by weight, particularly 0.05 to 5% by weight, and further 0.1 to 2% by weight. It is preferable to add them so that PH of supporting liquid is 5
It is preferable that it is -8, especially 6-7.5. Outside this range, the catalytic activity is relatively reduced.

The method of impregnating the supporting liquid is not particularly limited, but it can be carried out by spraying, dipping or the like. After impregnation, it is usually stabilized by drying, firing or the like. Although the firing temperature varies depending on other firing conditions such as firing time, it is generally 300 to 800 ° C, particularly 400 to 800 ° C.
Furthermore, 500-700 degreeC is preferable. Although the firing time varies depending on other firing conditions such as temperature, it is generally 0.05
~ 20 hours, especially 0.1-10 hours, and even 0.2-
5 hours is preferred. It is preferable to perform calcination at a temperature equal to or higher than the heat treatment temperature such as calcination in the step of producing the catalyst carrier. Drying and firing are carried out in a gas atmosphere such as air or nitrogen, but it is particularly preferred to carry out in air. The reduction is preferably carried out in an air stream containing hydrogen.

[Isomerization Reaction] As the hydrocarbon used as a raw material for the isomerization reaction of the present invention, the total amount of saturated hydrocarbons having 7 and 8 carbon atoms is 50% by weight or more, preferably 70% by weight of the entire raw material. A hydrocarbon that occupies the above is used. As such a hydrocarbon, a heavy naphtha fraction obtained by distilling crude oil from an atmospheric distillation or a fluid catalytic cracking apparatus, or a fraction obtained by further distilling and separating it can be used.

The isomerization reaction temperature is 130 to 160 ° C, preferably 140 to 155 ° C. Below this temperature range, the isomerization reaction does not substantially proceed, and above this temperature range, the decomposition reaction mainly occurs. Preferred reaction conditions are a reaction pressure of 0.5 to 10 MPa and LHS.
V is 0.2 to 10 / hr, and the hydrogen / raw material ratio is equal to or more than the amount of hydrogen necessary for saturating the unsaturated components (olefin content, aromatic content) contained in the raw material hydrocarbon, particularly 0.01 to 1
It is 0 mol / mol.

It is preferable that the water content coexisting during the isomerization reaction is low. The water content in the hydrocarbon is 15 ppm or less, more preferably 10 ppm or less, and particularly 5 ppm
The following is preferable. As the water content in hydrogen,
It is preferably 15 ppm or less, more preferably 10 ppm or less, and particularly preferably 5 ppm or less. Within this range, the decomposition of hydrocarbons is suppressed and the branched hydrocarbon yield and liquid yield are improved.

The isomerization reaction is preferably carried out under a pressure of 1.5 to 10 MPa, particularly 2 to 5 MPa.
If it is less than this range, hydrocarbons are easily decomposed, so that the liquid yield is lowered.

The reaction product obtained by this hydrocarbon isomerization method is separated into a fraction mainly containing branched hydrocarbons and a fraction mainly containing straight chain hydrocarbons, and the straight chain hydrocarbons are mainly separated. It is also possible to carry out further isomerization using the fraction containing in the above as a raw material. An example of the isomerization reactor is shown in FIG. The hydrocarbon raw material 10 is introduced into the dehydrator 20 together with the supply hydrogen 11 to reduce the water content, and then introduced into the first reactor 30 filled with the catalyst,
Isomerized. The product of the first reactor 30 is the separation column 4
Unreacted component 41 mainly containing straight chain hydrocarbons not isomerized at 0, gasoline base material 42 mainly containing isomerized and branched hydrocarbons, methane, ethane, etc. generated by decomposition of hydrogen and hydrocarbons And a gas component 43 containing. The unreacted component 41 is mixed with the hydrocarbon raw material 10 and recycled to be used as a raw material for the isomerization reaction again. The gasoline base material 42 is blended with other base materials to produce a gasoline product. The gas component 43 is a hydrogen separation tower 50.
Is divided into hydrocarbon gas 51 and recycled hydrogen 52,
The recycled hydrogen 51 is mixed with the supplied hydrogen 11 and reused. Instead of recycling the unreacted component 41, a second reactor (not shown) filled with a catalyst may be separately provided to further isomerize the unreacted component 41.

[0033]

EXAMPLES The present invention will be described in detail below with reference to examples.

[Measurement Method of Average Particle Size of Aggregated Particles] The measurement was performed by a wet measurement method using a MICROTRAC particle size analyzer manufactured by Nikkiso Co., Ltd. In this method, powder is dispersed in water, a flowing aggregated particle group is irradiated with laser light, and particle size analysis is performed by the forward scattered light.

[Measurement Method of Pore Structure] The specific surface area and the pore structure in the range of 0.002 to 0.05 μm in diameter are ASAP24 manufactured by Micromeritics.
It measured by the nitrogen adsorption method using the 00 type measuring device. For the range of pore diameter of 0.05 to 10 μm, Microm
It was measured by mercury porosimetry using an AutoPore 9200 type measuring instrument manufactured by Eritics.

[Measurement Method of Average Crush Strength] Using a Toyama Sangyo Co., Ltd. TH-203CP tablet breaking strength measuring instrument,
The side surface crush strength was measured using a sample that was extrusion molded into a cylindrical shape, dried, and fired. The measurement probe used had a circular tip with a diameter of 4.5 mm. The operation of applying the measurement sample to the center of the side surface of the cylindrical sample and performing the measurement 2
The measurement was repeated 0 times and the average value was calculated.

[Preparation of Catalyst] Commercially available dry zirconium hydroxide was dried to obtain a powder having an average particle size of 1.5 μm as a hydrous zirconia powder. Further, a commercially available pseudo-boehmite powder having an average particle size of 10 μm was used as the hydrous alumina powder.
1860 g of the hydrous zirconia powder and 1120 g of the hydrous alumina powder were added, 575 g of ammonium sulfate was further added, and kneading was performed for 45 minutes while adding water with a kneader equipped with a stirring blade. The obtained kneaded product was extruded from an extruder having a circular opening with a diameter of 1.6 mm to form a cylindrical pellet, which was dried at 110 ° C. to obtain a dry pellet. Subsequently, a part of the dried pellet was calcined at 675 ° C. for 1.5 hours to obtain a carrier A.

The shaped carrier A has an average diameter of 1.4 m.
It had a columnar shape of m and an average length of 4 mm, and had an average crushing strength of 3.6 kg. The specific surface area of the carrier A is 158 m ² /
g, pore volume of 0.002 to 10 μm is 0.3
It was 1 ml / g. Pore diameter of carrier A 0.002
The median pore diameter in the range of 0.05 μm was 55Å.

An aqueous solution of dichlorotetraammineplatinum ((NH ₃ ) ₄ PtCl ₂ ) was added to 125 g of the carrier A so that the amount of platinum in the catalyst would be 0.33% by weight (pH: 7.
0) was spray-loaded. This was dried and then calcined at 680 ° C. for 0.5 hour to obtain about 125 g of catalyst A.

The average crushing strength of the catalyst A was 3.7 kg, the proportion of zirconia in the catalyst A was 44.2% by weight as zirconium element weight, and the proportion of alumina was 15.0% by weight as aluminum element weight and sulfuric acid content. Of the elemental sulfur is 2.7% by weight, and the nitrogen content is 0.01%.
It was less than weight%. The specific surface area of catalyst A is 158 m ² /
g, pore volume of 0.002 to 10 μm is 0.3
The median pore diameter in the range of 1 ml / g and the pore diameter of 0.002 to 0.05 μm was 60Å.

[Heavy naphtha isomerization reaction] 4 cc of a catalyst (catalyst A) having a particle size of 16 to 24 mesh and a length of 50 c
It was filled in a fixed-bed flow reactor having an inner diameter of m and an inner diameter of 1 cm, and after the pretreatment, a hydrocarbon isomerization reaction was performed. The pretreatment was performed at a temperature of 400 ° C., a pressure of normal pressure, and an atmosphere of air for 1 hour. After that, without introducing air, the inside of the reactor was made into a nitrogen atmosphere and further into a hydrogen atmosphere, and then the isomerization reaction was started.

Hydrocarbons used as reaction raw materials include normal hexane (n-C6) and normal heptane (n-C).
7), normal octane (n-C8) or a mixture (n-C7 + C8) of 50 wt% of normal heptane and 50 wt% of normal octane was used. The concentration of the sulfur compound as the raw material used was 1 wt ppm or less in terms of sulfur, the concentration of nitrogen compound was 0.1 wt ppm or less in terms of nitrogen, the concentration of oxygen compounds other than water was 0.1 wt ppm or less in terms of oxygen, and chlorine compound Was 0.1 weight ppm or less in terms of chlorine.

The hydrogen gas used in the reaction has a purity of 99.
99% by volume, water content is 0.5 ppm by weight or less, and as other impurities, the concentration of sulfur compounds is 1 ppm by weight or less in terms of sulfur, the concentration of nitrogen compounds is 0.1 ppm by weight or less, oxygen other than water. The concentration of the compound was 0.1 weight ppm or less in terms of oxygen, and the concentration of the chlorine compound was 0.1 weight ppm or less in terms of chlorine.

The isomerization reaction has a reaction pressure of 1.0 MPa,
LHSV = 2.0 / hr, hydrogen / oil ratio (H ₂ / Oi
1): 5 (mol / mol). Start oiling 200
The composition of the reaction tube outlet after the elapse of time was analyzed by gas chromatography. The weight% other than the reaction raw materials in the reaction product is taken as the conversion rate, the weight% of the components having 5 or more carbon atoms contained in the reaction product is taken as the liquid yield, and the weight percentage of the components having 4 or less carbon atoms contained in the reaction product is The weight% of the component was evaluated as the decomposition product yield, and the weight% of the branched aliphatic hydrocarbon having 5 or more carbon atoms contained in the reaction product was evaluated as the iso-C5 + yield.

Normal hexane (n-C6) was used as a reaction raw material.
Is shown in Table 1, evaluation results in the case of using normal heptane (n-C7) are shown in Table 2, and results of evaluation in the case of using normal octane (n-C8) are shown in Table 3.
Further, Table 4 shows the evaluation results when the mixture (n-C7 + C8) was used. From Table 1, it can be seen that the isomerization of normal hexane is difficult to proceed at a reaction temperature of less than 160 ° C. It can be seen from Tables 2 and 3 that normal heptane and normal octane have a high conversion rate and liquid yield at 135 to 150 ° C., particularly 140 to 145 ° C. and are difficult to decompose. It can be seen from Table 4 that the conversion rate and liquid yield are high at 130 to 140 ° C. even when normal heptane and normal octane are mixed.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

[Table 3]

[0049]

[Table 4]

In the above isomerization reaction, the water content in the raw material oil was removed by the molecular sieve 3A (1/16 inch) to make the water content 5 ppm, but it was not dehydrated sufficiently.
Table 5 shows a comparison with the case of containing ppm water. Regarding the reaction conditions, normal heptane was used as the feed oil,
The same isomerization reaction as described above was performed except that the reaction temperature was 140 ° C. As a result, although the conversion rate was low, the cracking reaction, which is not preferable for the gasoline production process, was suppressed, and the isomerization selectivity was improved.

[0051]

[Table 5]

Table 6 shows the reaction results when the reaction pressure was changed. Regarding the reaction conditions, the same isomerization reaction as described above was performed except that normal heptane was used as the feed oil and the reaction temperature was 140 ° C. As a result, 3.6 MPa, 5.
At 0 MPa, the decomposition reaction was suppressed and the yield of branched products was improved.

[0053]

[Table 6]

[Brief description of drawings]

FIG. 1 is a diagram showing an embodiment of an isomerization reaction device. 10 Hydrocarbon raw materials 11 Supply hydrogen 20 Dehydrator 30 First reactor 40 Separation tower 41 unreacted components 42 Gasoline base material 43 gas components 50 hydrogen separation tower 51 hydrocarbon gas 52 Recycled hydrogen

Claims (5)

[Claims] 1. A reaction temperature of 130 to 160 in the presence of hydrogen.
Carbonization at 50 ° C. by contacting a hydrocarbon containing 50% by weight or more of a saturated hydrocarbon having 7 and 8 carbon atoms with a solid acid catalyst having a sulfuric acid component and a platinum group metal component supported on a carrier containing a zirconia portion and an alumina portion. Hydrogen isomerization method. 2. A solid acid catalyst in which the zirconia portion contains tetragonal zirconia, the alumina portion contains γ-alumina, and the platinum group metal component is crystallized.
Method for Isomerizing Hydrocarbons. 3. The method for isomerizing hydrocarbons according to claim 1, wherein the total water content of the hydrocarbons and hydrogen used in the isomerization reaction is 15 ppm or less. 4. The method for isomerizing hydrocarbons according to claim 1, wherein the isomerization reaction is carried out under a pressure of 1.5 to 10 MPa. 5. The reaction product obtained by the method for isomerizing hydrocarbons according to claim 1 is separated into a fraction mainly containing branched hydrocarbons and a fraction mainly containing straight chain hydrocarbons, and directly separating the fractions. The method for isomerizing hydrocarbons according to claim 1, wherein a fraction containing mainly chain hydrocarbons is used as a raw material.