JP4294569B2 - High octane method for petrochemical raffinate - Google Patents

Description

  The present invention relates to a method for increasing the octane number of petrified raffinate. More specifically, in the petrochemical industry, petrochemical raffinate, which is a by-product of petrochemical equipment such as ethylene equipment and catalytic reforming equipment, has not been effectively used as a gasoline base material because of its low octane number. The present invention relates to a method for effectively utilizing petrochemical raffinate as a high-quality gasoline base material by improving its octane number and improving the quality as a gasoline base material.

  With the internationalization of the oil industry, oil companies are promoting thorough efficiency and rationalization in the fields of refining, logistics, and sales in order to secure international competitiveness. On the other hand, in the automobile fuel field, suppression of exhaust gas from gasoline automobiles and cleanliness have become important issues, and the quality of automobile gasoline is required to have low sulfur content and low vapor pressure in order to cope with it. On the other hand, in the petrochemical field, surplus of petrochemical raffinate by-produced from ethylene equipment is expected due to changes in the demand structure and supply / demand balance of ethylene, propylene and the like. Under such circumstances, surplus petrochemical raffinate by-produced from petrochemical equipment such as ethylene equipment and catalytic reforming equipment, especially petrochemical raffinate mainly composed of C6 to C8 fractions has low sulfur and low vapor pressure. Nevertheless, since the octane number is as low as 50 to 60, it has not been used effectively as a gasoline base material in the automobile fuel field. In the petrochemical field, this surplus petrochemical raffinate has been recycled to the ethylene equipment as a raw material, but this recycling method has a particularly high naphthene content due to the composition of the raw material. In addition, a decrease in the yield of ethylene has been recognized, and another effective method for utilizing the petrified raffinate has been demanded from the viewpoint of the efficiency of the ethylene apparatus.

  In the automotive fuel field, conventionally, as a technique for improving the octane number of hydrocarbons having a low octane number and obtaining high-quality hydrocarbons as a gasoline base material, there has been a method of isomerizing light hydrocarbons. Yes (see, for example, Patent Document 1). In this method, a light fraction mainly composed of C5 to C6 normal paraffins, such as straight-run light naphtha from crude oil, is isomerized by contacting with an isomerization catalyst, and its main component C5 to C6 normal is obtained. It is a method aimed at increasing the octane number of the light fraction by converting paraffins to isoparaffins. However, even if this conventional method for isomerizing light hydrocarbons is applied to relatively heavy fossilized raffinate containing C7 to C8 paraffins and naphthenes, the C3 to C4 fraction is generated. In addition, polymerization or coking occurs and the isomerization catalyst is deactivated, so that it is difficult to suitably perform the desired isomerization, and it is difficult to increase the octane number of the petrified raffinate. Therefore, the high octane conversion of petrochemical raffinate has not been demonstrated yet.

Japanese Examined Patent Publication No. 6-29199

  Therefore, in view of the above-described conventional situation, an object of the present invention is to provide a method for increasing the octane number of a petrochemical raffinate in order to effectively utilize the surplus petrochemical raffinate as a high-quality gasoline base material having a high octane number. There is.

As a result of diligent research to achieve the above object, the present inventors have found that the above object can be achieved by the following high octane numbering method for petrochemical raffinate, and the present invention has been completed.
That is, the present invention provides the following method for increasing the octane number of petrified raffinate in order to achieve the above object.

(1) A boiling point range of 60 to 150 ° C. and a high octane numbering method for petrochemical raffinate mainly composed of C6 to C8 fractions, wherein the petrified raffinate is divided into two fractions, a light fraction and a heavy fraction. A distillation step, an isomerization step of isomerizing the light fraction obtained in the distillation step, an isomerization product obtained in the isomerization step, and a heavy fraction obtained in the distillation step high octane method petrochemical raffinate, characterized in that the successively viewed including the steps of blending, and C7 content in the distillation step light fraction obtained in less than 10% by weight.
( 2 ) In the isomerization step, the isomerization treatment method for the light fraction of the petrochemical raffinate is an isomerization treatment method using a solid superacid catalyst. Octane numbering method.
( 3 ) The solid superacid catalyst is made of at least one group IV metal hydroxide or oxide selected from silicon, titanium, zirconium and tin, and aluminum hydroxide or oxide. Containing at least one kind of periodic table group VIII metal selected from nickel, ruthenium, rhodium, palladium, and platinum, and a sulfate group or a sulfate group precursor in a carrier composed of at least one selected, calcined, The method for increasing the octane number of a petrified raffinate according to the above ( 2 ), which is a stabilized catalyst.
( 4 ) The carrier is at least one selected from a hydroxide or oxide of zirconium and an aluminum hydroxide or oxide, and the group VIII metal of the periodic table is platinum. The method for increasing the octane number of the petrified raffinate according to ( 3 ) above.
( 5 ) In the isomerization treatment step, after mixing a straight-run light naphtha with a light fraction of a petrochemical raffinate, the mixture is isomerized, and any one of the above (1) to ( 4 ) The method for increasing the octane number of the petrochemical raffinate described in 1.
( 6 ) The method for increasing the octane number of petrified raffinate according to ( 5 ), wherein the straight-run light naphtha has a boiling range of 25 to 110 ° C.

  According to the method of the present invention, the petrochemical raffinate, which has been conventionally difficult to be used as a gasoline base material with a low octane number, can be improved in octane number by 8 to 10 and is effectively used as a high-quality gasoline base material having a high octane number. be able to.

  The petrochemical raffinate referred to in the present invention corresponds to a by-product produced as a by-product from a petrochemical apparatus such as an ethylene apparatus or a catalytic reformer. Specifically, in the catalytic reformer, generally, straight-run naphtha is used as a raw material, and it is subjected to a catalytic reforming reaction to obtain a reformed gasoline, and the obtained reformed gasoline is used as a gasoline base material. However, it is generally used after removing benzene in the reformed gasoline due to environmental regulations. In this benzene removal method, benzene in the reformed gasoline is removed by distillation or the like, but only the benzene is extracted from the crude benzene fraction obtained by this distillation operation by an aromatic extraction apparatus. The fraction remaining after these operations, that is, the raffinate after extracting benzene from the crude benzene fraction, is a petrochemical raffinate derived from a catalytic reformer. Further, in an ethylene apparatus, light naphtha is generally used as a raw material, and it is thermally decomposed to produce ethylene. At that time, a cracked gasoline fraction is by-produced. Since this by-product cracked gasoline contains aromatic compounds such as benzene, toluene, and xylene, the petrochemical industry extracts aromatics from this by-product cracked gasoline with an aromatic extractor. The extracted aromatic component is effectively used as a petrochemical raw material. The raffinate after the aromatic component is extracted from the by-product cracked gasoline is a petrochemical raffinate derived from an ethylene apparatus.

  The petrified raffinate to be treated in the present invention is a fraction rich in normal paraffins having a boiling range of 60 to 150 ° C. and mainly consisting of C6 to C8 fractions. The composition of the petrified raffinate to be treated in the present invention generally has a paraffin content of 20 to 85 vol%, a naphthene content of 15 to 65 vol%, an olefin content of 5 vol% or less, and an aromatic content of 10 vol% or less.

Hereinafter, exemplary embodiments of the present invention will be described specifically and in detail with reference to the drawings. FIG. 1 is a process flow sheet conceptually showing an example of an embodiment of the present invention. FIG. 2 is a process flow sheet conceptually showing another example of the embodiment of the present invention.
In the embodiment shown in FIG. 1, the petrochemical raffinate 1 is divided into two fractions, a light fraction 3 and a heavy fraction 4, by a precision distillation apparatus 2 in the distillation step, and the light fraction 3 is separated from the isomerization step. The isomerization is performed by the isomerization apparatus 5. The isomerized product oil 6 subjected to the isomerization treatment is then blended with the heavy fraction 4 divided by the precision distillation apparatus 2 in the blending process to obtain a high-octane number and high-quality gasoline base material 6.
In the embodiment shown in FIG. 2, the light fraction 3 divided in the distillation step is mixed with the straight-run light naphtha 7 and then supplied to the isomerization device 5. This light fraction 3 is the same as the embodiment shown in FIG. 1 except that the light fraction 3 is mixed with the straight light naphtha 7 and then supplied to the isomerization device 5.

Hereinafter, each process will be described in detail.
(Distillation process)
Separation of the light fraction and heavy fraction of the petrochemical raffinate can be carried out using a conventional distillation column. As this distillation column, a precision distillation column is preferable. Further, the separation of the petrochemical raffinate is desirably carried out by distillation cutting so that the C7 fraction in the light fraction is less than 10% by mass, preferably less than 7% by mass, and more preferably less than 3% by mass.
The separation distillation of the petrochemical raffinate is generally performed at a pressure of 0.1 to 2 MPa, preferably 0.2 to 1 MPa, and the theoretical number of distillation columns is 10 to 100, preferably 30 to 70. . The reflux ratio represented by the ratio between the liquid flow rate in the column and the charged raw material flow rate is preferably 1-20, more preferably 1-10.
In the light fraction, it is preferable to cut between the boiling points of methylcyclopentane (boiling point 71.8 ° C.) and 2,2-dimethylpentane (boiling point 79.2 ° C.). In this isomerization reaction, when the C7 content is large, coke deposition on the catalyst and a decrease in the liquid yield are suppressed. For this reason, although preferable cut temperature is based also on precision distillation conditions, it is 70-80 degreeC.
In the present invention, C5 and C6 naphthenes are contained in the light fraction, but the total amount of C5 naphthene and C6 naphthene in the light fraction is 15 to 65% by mass.

(Isomerization process)
The light fraction of petrochemical raffinate separated in the distillation step is introduced into an isomerization apparatus and subjected to isomerization treatment. It is generally desirable that the isomerization reaction conditions are as follows.
Reaction temperature: 150-250 ° C, preferably 170-220 ° C
Reaction pressure: 1-5 MPa, preferably 2-4 MPa
Hydrogen / oil ratio: 1-4 mol / mol, preferably 1.5-3 mol / mol
WHSV: 0.1 to 5 / h, preferably 0.5 to 2 / h
It is preferable that the reaction temperature is higher than 150 ° C., since the catalyst life of the isomerization catalyst can be prevented from being shortened. Moreover, it is preferable to make it 250 degrees C or less, since decomposition | disassembly of a light fraction advances and it can prevent that a liquid yield falls. Moreover, it is preferable that the water content in the raw material hydrocarbon is 30 mass ppm or less because the decrease in the activity of the catalyst is not increased.

In the present invention, in the embodiment as shown in FIG. 1, the light fraction of the petrified raffinate is directly introduced into the isomerization apparatus and subjected to isomerization. In the embodiment shown in FIG. A straight-run light naphtha is mixed with the light fraction, and the mixture is introduced into an isomerization apparatus to be isomerized. The mixing ratio of the light fraction of petrochemical raffinate and straight light naphtha can be arbitrarily set, but from the viewpoint of suppressing the ring-opening reaction of naphthene in the light fraction, the light fraction of petrochemical raffinate / The straight-run light naphtha ratio (mass ratio) is suitably 1: 0 to 1: 4.
As the straight-run light naphtha to be mixed with the light fraction of petrochemical raffinate, a product obtained by subjecting light naphtha distilled from a crude oil atmospheric distillation device to desulfurization treatment is preferable. In particular, a preferred straight-run light naphtha is a light naphtha having a boiling range of 25 to 110 ° C. Further, the sulfur content is 1 mass ppm or less, preferably 0.5 mass ppm or less. If the sulfur content is 1 mass ppm or less, there is no concern about the deterioration of the activity of the isomerization catalyst.

(Isomerization reaction catalyst used in the isomerization process)
In the isomerization step of the present invention, various isomerization reaction catalysts can be appropriately used as the isomerization reaction catalyst. However, solid superacid catalysts such as Pt / SO ₄ / ZrO ₂ solid superacid catalysts are used. Preferably used. The solid superacid catalyst mentioned here has the property of an acid stronger than 100% sulfuric acid, which is defined as a superstrong acid, and the skeletal isomerization reaction of paraffins at low temperature, which is advantageous in terms of thermodynamic equilibrium, proceeds even at room temperature. A catalyst supporting a super strong acid having such a property as to have an acid strength of 100% sulfuric acid or higher, and usually 100% sulfuric acid H ₀ = -11.93 or lower in terms of Hammett acidity function. A solid catalyst. For example, a catalyst supporting a compound having super strong acidity such as SbF ₅ or BF ₃ , a catalyst obtained by treating an oxide such as ZrO ₂ or Fe ₂ O ₃ with sulfuric acid, a fluorinated sulfonic acid resin or the like An example of a strong acid catalyst can be given.

  The composition of the solid superacid catalyst comprises a group consisting of at least one metal hydroxide or oxide selected from Group IV or Group III on the Periodic Table, Group VIII, Group VIA, Group VIA, And at least one metal selected from Group IB (hereinafter referred to as a specific metal) and a sulfate radical or a precursor of a sulfate radical, and is fired and stabilized. Here, any of the specific metals or metal compounds can be supported on the carrier by a usual impregnation method, ion exchange method or the like. Preferred specific examples of the specific metal include nickel, ruthenium, rhodium, palladium, platinum, iron, manganese, chromium, silver, and copper. As for content of a specific metal, 0.01-10 mass parts is preferable with respect to 100 mass parts of support | carriers. The reason for this is that if 0.01 parts by mass or more, the catalytic activity effect of the metal is small and the stability of the catalytic activity can be prevented from becoming insufficient, and if it is within 10 parts by mass, the acid strength This is because it is possible to prevent the decrease in the isomerization rate and the isomerization rate in the isomerization reaction. Examples of sulfate radicals include, for example, 0.005 to 5 mol / liter, preferably 0.05 to 2.5 mol / liter sulfuric acid, 0.1 to 10 mol / liter ammonium sulfate, and the like. For example, substances that generate sulfate radicals after catalytic calcination treatment such as hydrogen sulfide and sulfurous acid gas can be used.

  Among the solid superacid catalysts, a more preferred solid superacid catalyst is at least one group IV metal hydroxide or oxide selected from silicon, titanium, zirconium and tin, and aluminum water. A support comprising at least one selected from oxides or oxides, at least one group VIII metal selected from nickel, ruthenium, rhodium, palladium and platinum as a specific metal, and a sulfate group or sulfate group A catalyst containing a precursor, calcined and stabilized. An even more preferred solid superacid catalyst is a catalyst in which the support is a hydroxide or oxide of zirconium and the group VIII metal of the periodic table is platinum.

  The method for preparing the solid superacid catalyst used in the method of the present invention is not particularly limited. That is, the method for supporting the specific metal and the sulfate radical may be performed by any method. For example, after introducing the group VIII metal onto the carrier, the treatment with a treatment agent containing a sulfate radical is performed, and the firing stability is improved. Thus, a solid superacid catalyst can be prepared. Taking platinum as an example of the specific metal, it can be supported by immersing the carrier in an aqueous solution of chloroplatinic acid, tetraammineplatinum complex or the like, and after the carrying, treatment with a sulfate group-containing treatment agent or the like is performed. At that time, as a treating agent containing a sulfate group, 0.005 to 5 mol / liter, preferably 0.05 to 2.5 mol / liter sulfuric acid, 0.1 to 10 mol / liter ammonium sulfate or the like is used as a catalyst mass. Use 1 to 10 times the amount. In addition, the same effect can be obtained by using a treatment agent that generates sulfate radicals after catalyst firing treatment such as hydrogen sulfide and sulfurous acid gas. In addition, after the treatment with a sulfate group-containing treatment agent or the like, a firing stabilization treatment is performed for 0.5 to 10 hours in an oxidizing atmosphere at a temperature of 450 to 800 ° C., preferably 500 to 700 ° C. By the above treatment, a solid super strong acid catalyst showing strong acidity can be obtained as an isomerization reaction catalyst. It should be noted that the catalyst's firing stabilization treatment is performed in an oxidizing atmosphere because the catalytic activity decreases on the specific metal or the specific metal compound due to a change in the binding state of sulfate radicals or a phenomenon that seems to be reductive decomposition. It is for preventing.

  Prior to use in the isomerization reaction, the solid super strong acid catalyst is preferably subjected to pretreatment for stabilization of its catalytic activity, that is, reduction of the supported metal compound to metal and activation of strong acid sites. The pretreatment conditions are normal pretreatment conditions for the solid superacid catalyst. For example, the solid superacid catalyst is dried at a temperature of 100 to 500 ° C. for 1 to 5 hours, and then dried at 100 to 400 ° C. Reduction treatment is performed at temperature.

(Blend process)
It is obtained by isomerizing the isomerized product oil obtained by isomerizing the light fraction of the petrochemical raffinate in the above isomerization process, or a mixture of the light fraction of the petrochemical raffinate and straight-run light naphtha. By blending the isomerized product oil and the heavy fraction of the petrified raffinate obtained in the distillation step, a high-quality gasoline base material having a high target octane number can be obtained.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example.

Example 1
By the bench apparatus corresponding to the embodiment shown in FIG. 1, the petrochemical raffinate derived from the catalytic reformer having the properties shown in Table 1 is used to increase the octane number by the following operation, and the gasoline base material has a high quality. A petrified raffinate was prepared.
The petrified raffinate having the properties shown in Table 1 was divided into a light fraction and a heavy fraction by an Oldershaw type distillation apparatus. The amount of light fraction extracted at the time of precision distillation is adjusted according to the temperature at the top of the distillation column, and the boiling point of methylcyclopentane is 71.8 ° C., and the C7 heavy fraction in the light fraction is 1% by mass or less. Distillation was performed as follows. The distillation conditions at that time are shown below.
The calculated octane number in the table is an integrated value obtained by multiplying the octane number specific to each component in the produced oil (C5 or higher) by the volume ratio.

Type Oldershaw type Theoretical plate number 50 plate Reflux ratio 5
Processing volume 10L

  Table 1 shows the properties and recovery rates of the light and heavy fractions divided by precision distillation. The yield of the light fraction was 43.2% by mass, the yield of the heavy fraction was 53.2% by mass, and the recovery rate was 96.4% by mass. Moreover, the octane numbers of the respective fractions were 51.4 and 61.3.

The isomerization treatment of the obtained petrified raffinate light fraction was performed in a bench plant having a catalyst filling amount of 7 ml. The catalyst used in the isomerization reaction was a Pt / SO ₄ / ZrO ₂ -based catalyst, and an in-situ reduction treatment was performed as a catalyst pretreatment before introducing the isomerization raw material. The reduction conditions were a hydrogen flow rate of 9 L / H, a preliminary drying at 150 ° C. for 3 hours, and a treatment at 220 ° C. for 14 hours to activate the catalyst. After the pretreatment, an isomerization treatment was carried out under the reaction conditions shown below.

Hydrogen partial pressure 3.1 MPa
Space velocity (WHSV) 1.5 / h
Hydrogen / hydrocarbon ratio 2 mol / mol
Reaction temperature 160, 170, 180, 190, 200 ° C

  Table 2 shows the results of the isomerization treatment of the lightened raffinate light fraction (properties of the isomerized product oil). As a result of the isomerization reaction, the octane number of the produced oil was 70.4 to 76.0, and the liquid yield at that time was 98.8 to 93.1%.

The above petrified raffinate light fraction (isomerized product oil) that has been subjected to the above isomerization treatment and the petrochemical raffinate heavy fraction obtained by the above precision distillation are blended to achieve the desired high octane number and increase the gasoline base. A quality petrified raffinate was obtained. The results (characteristics of target high octane fossilized raffinate) are shown in Table 3 (in Table 3, “target high octane number fossilized raffinate” is indicated as “isomerized gasoline”).
From the result, it was found that the octane number of the target petrified raffinate was increased by about 10.8 to 8.5 from the octane number 56.8 of the petrified raffinate raw material to 67.4 to 65.4.

Example 2
Using the same petrochemical raffinate as used in Example 1, the bench apparatus corresponding to the embodiment shown in FIG. 2 is operated as follows to produce a high-quality petrochemical raffinate as a gasoline base material. did.
In the same manner as in Example 1, the petrochemical raffinate was divided into a light fraction and a heavy fraction so that the C7 content was 3% by mass or less to obtain a light fraction and a heavy fraction. Table 4 shows the properties of the light fraction. The light fraction thus obtained was subjected to desulfurization straight run light naphtha having the properties shown in Table 4, with a light fraction / straight run light naphtha ratio (mass ratio) of 35/65 and 50/50. By mixing, a mixture of petrochemical raffinate light fraction and straight-run light naphtha was obtained. The properties of the obtained mixture are shown in Table 5 together with the properties of the raw materials (lighted raffinate light fraction and straight-run light naphtha).

  The obtained mixture of the petrified raffinate light fraction and straight light naphtha was hydrotreated under the same reaction conditions as in Example 1 using the same isomerization catalyst as in Example 1. The results (property of the isomerized product oil) are shown in Table 6 when the fossilized raffinate light fraction / straight-run light naphtha mixture ratio is 50/50, and in Table 7 when the mixture ratio is 35/65. Each is shown.

Blend of the above-mentioned isomerization-treated petrochemical raffinate light fraction and straight-run light naphtha (isomerized oil) and the petrochemical raffinate heavy fraction obtained by the above-mentioned precision distillation to achieve the desired high octane number As a gasoline base material, high-quality petrochemical raffinate was obtained. The results (characteristics of the desired high-octane fossilized raffinate) are shown in Table 8 when the fossilized raffinate light fraction / straight-run light naphtha mixing ratio is 50/50, and when the mixing ratio is 35/65. The results are shown in Table 9 (in Tables 8 and 9, “target high octane fossilized raffinate” is indicated as “isomerized gasoline”).
From the results, it was found that the octane number was improved by 4 to 7 when the petrified raffinate light fraction / straight-run light naphtha mixture ratio was 50/50. Moreover, when the said mixture ratio was 35/65, it turned out that an octane number improves 6-2.

It is a process flow sheet which shows an example of an embodiment of the present invention notionally. It is a process flow sheet which shows notionally other examples of the embodiment of the present invention.

Explanation of symbols

1: Petrochemical raffinate 2: Precision distillation device 3: Light fraction 4: Heavy fraction 5: Isomer 6: Isomerized oil 7: Straight-run light naphtha

Claims (6)

A distillation step for dividing a petrified raffinate into two fractions, a light fraction and a heavy fraction, having a boiling range of 60 to 150 ° C. and a high octane numbering method for a petrochemical raffinate mainly comprising C6 to C8 fractions; Isomerizing the light fraction obtained in the distillation step, blending the isomerized product obtained in the isomerization step and the heavy fraction obtained in the distillation step sequentially viewed including the step, and the octane number of methods petrochemical raffinate, wherein the C7 content in the distillation step light fraction obtained in less than 10% by weight.   The method for isomerization of a petrochemical raffinate according to claim 1, wherein, in the isomerization step, the isomerization process for the light fraction of the petrified raffinate is an isomerization process using a solid superacid catalyst.   The solid superacid catalyst is selected from at least one Group IV metal hydroxide or oxide selected from silicon, titanium, zirconium, and tin, and aluminum hydroxide or oxide. At least one kind of carrier containing at least one group VIII metal selected from nickel, ruthenium, rhodium, palladium, and platinum and a sulfate radical or a sulfate radical precursor is fired and stabilized. The method for increasing the octane number of petrified raffinate according to claim 2, wherein   The carrier is at least one selected from a hydroxide or oxide of zirconium and a hydroxide or oxide of aluminum, and the group VIII metal of the periodic table is platinum. 4. A method for increasing the octane number of a petrochemical raffinate according to 3.   In the said isomerization process, after mixing a straight run light naphtha with the light fraction of a petrochemical raffinate, this mixture is isomerized, The petrochemical raffinate of any one of Claims 1-4 characterized by the above-mentioned. High octane method.   The method for increasing the octane number of a petrochemical raffinate according to claim 5, wherein the straight-run light naphtha has a boiling range of 25 to 110 ° C.

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