JP2005247932A - Method for producing high-octane-number gasoline base stock - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a high-octane-number gasoline base stock in high yields from mainly 4C hydrocarbons as a by-product from e.g., a catalytic cracking apparatus or a thermal cracking apparatus. <P>SOLUTION: The method for producing the high-octane-number gasoline base stock comprises reforming a hydrocarbon mixture containing at least 50 wt.% 4C hydrocarbons by bringing it into contact with a zeolite catalyst under such reaction conditions that the formed 5C or higher fraction satisfies the requirements: (1) the content of 5C or higher olefins is 5 to 90 wt.%, (2) the content of aromatics is 10 to 90 wt.%, (3) benzene accounts for at most 10 wt.% of the aromatics, and (4) 8C aromatics account for at least 30 wt.% of the aromatics and is characterized in that the formed 5C or higher fraction has a octane number by a research method of at least 95, and its % yield is at least 60 wt.% based on the hydrocarbon mixture as the feedstock. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a high octane gasoline substrate in a high yield from paraffins and / or olefins mainly comprising 4 carbon atoms, which are by-produced from a catalytic cracking apparatus, a thermal cracking apparatus or the like.

  Conventionally, catalytic reforming of straight run naphtha with a platinum / alumina catalyst has been widely used commercially as a method for obtaining gasoline having a high octane number. As a raw material naphtha in this catalytic reforming, a fraction having a boiling point of 70 to 180 ° C. is mainly used for automobile gasoline production, and an aromatic fraction such as xylene, so-called BTX production is used. A fraction of 60-150 ° C. is used. However, since the octane number of the product becomes low, for example, the conversion ratio to aromatics becomes low as the number of carbon atoms decreases, light hydrocarbons mainly composed of hydrocarbons (paraffins and / or olefins) lower than 6 carbon atoms. It is difficult to produce higher octane gasoline. Therefore, at present, the use of such light hydrocarbons is limited to petrochemical raw materials and city gas production raw materials.

In recent years, the trend of petroleum demand has continued to become white oil, and the ratio of secondary crackers to all petroleum refiners has increased. This trend is expected to increase in the future. Along with this, the proportion of light hydrocarbons in the final product per crude oil volume unit is expected to increase in the future. Under such circumstances, while demand for petrochemicals such as propylene having 3 carbon atoms is strong, it is predicted that the supply and demand balance will be maintained in the future, while hydrocarbons having 4 carbon atoms (paraffin and (And / or olefins) will become a surplus in the future in conjunction with the tightening of gasoline vapor pressure regulations.
Against this background, producing high-octane gasoline from light hydrocarbons, especially hydrocarbons with 4 carbon atoms (paraffins and / or olefins), increases the added value of light hydrocarbons, resulting in a shortage of high-octane gasoline base materials. As a response, it has been attracting a lot of attention. Further, since benzene contained in gasoline can cause environmental pollution as a leakage during handling or as an unburned component, it is desirable that the amount of benzene contained in the produced gasoline is small. Furthermore, this product contains not only a high octane number but also a large amount of aromatics having 8 carbon atoms (C8), which is an important petrochemical feedstock. From the viewpoint of flexibility that can be used as a raw material for chemicals as well as use as a component, it is widely excellent in economic efficiency.

As a technique related to the production of a high octane gasoline substrate, a method of contacting with a crystalline silicate, particularly a crystalline aluminosilicate having an MFI type structure and a crystalline metallosilicate is known. For example, according to Patent Document 1, a fired product of crystalline gallium silicate represented by the composition formula 2Na ₂ O: 9 (C ₃ H ₇ ) ₄ NOH: 0.33Ga ₂ O ₃ : 25SiO ₂ : 450H ₂ O Specifically, a method for aromatizing n-butane and propane using a catalyst obtained by calcination after ammonium exchange is shown. According to Patent Document 2, light hydrocarbons having 2 to 7 carbon atoms are formed as SiO ₄ , AlO ₄ and GaO ₄ tetrahedrons under conditions of a temperature of 350 to 650 ° C. and a hydrogen partial pressure of 490 kPa (5 kg / cm ² ) or less. A method for producing a high octane gasoline substrate by contacting with a crystalline aluminogallosilicate having a skeleton formed therein is shown. However, in these conventional methods, the yield of a high octane gasoline base from light hydrocarbons is low, the content of benzene contained in the obtained gasoline component is high, and conversely, even among aromatics, the octane number is high and petroleum Industrially, it was not satisfactory because the ratio of C8 aromatics useful as chemical materials was low.
JP 59-98020 A JP 62-254847 A

  The present invention relates to a method for producing a high octane gasoline base material using light hydrocarbons as a raw material, and has a higher gasoline yield and lower benzene concentration in the gasoline fraction than the prior art, and a C8 aromatic fraction. It aims at providing the manufacturing method with high partial concentration.

  As a result of intensive studies to solve the above problems, the inventors of the present invention brought a high octane number by bringing a fraction mainly containing hydrocarbons having 4 carbon atoms into contact with a zeolite catalyst under appropriate reaction conditions. The present inventors have found a production method capable of obtaining a gasoline fraction having a high C8 aromatic yield not only having a low benzene concentration and a high octane number but also having a high C8 aromatic yield as a petrochemical raw material in a high yield. .

That is, the present invention is such that a hydrocarbon mixture containing 50% by weight or more of a hydrocarbon having 4 carbon atoms is brought into contact with a zeolite catalyst, and the resulting fraction having 5 or more carbon atoms is Content: 5 to 90% by weight
(2) Aromatic content: 10 to 90% by weight
(3) Ratio of benzene in aromatics: 10% by weight or less (4) Ratio of aromatics having 8 carbon atoms in aromatics: reformed and produced under reaction conditions of 30% by weight or more The present invention relates to a method for producing a high-octane gasoline base material, wherein a fraction having 5 or more carbon atoms has a research octane number of 95 or more and a yield of 60% by weight or more based on a hydrocarbon mixture as a raw material.

Details of the present invention will be described below.
The hydrocarbon mixture which is a raw material oil in the present invention contains a hydrocarbon having 4 carbon atoms in an amount of 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight or more. When the hydrocarbon having 4 carbon atoms is less than 50% by weight, the proportion of the aromatic fraction having a high octane number, such as C8 aromatic, decreases, and the octane number of the generated gasoline fraction becomes low. It is not preferable. The hydrocarbon mixture of the present invention preferably contains 90% by weight or more of hydrocarbons having 2 to 7 carbon atoms, preferably 3 to 6 carbon atoms. When this content is less than 90% by weight, the yield of a gasoline fraction having 5 or more carbon atoms may be lowered. Furthermore, the total content of paraffin in the hydrocarbon mixture of the present invention is preferably 70% by weight or less, more preferably 60% by weight or less. When the total content of paraffin exceeds 70% by weight, the yield of 5 or more carbon atoms in the product may decrease as the reactivity decreases.

  Such a raw material hydrocarbon mixture is obtained from, for example, a catalytic cracking apparatus or a thermal cracking apparatus. The reforming technique of the present invention is intended to produce a high octane gasoline substrate in which a polymerized olefin and an aromatic coexist, among a series of reactions for producing an aromatic through dehydrogenation and polymerization. At this time, since the raw material oil contains a large number of substances having 4 carbon atoms, the olefin having 8 carbon atoms produced by the polymer and the aromatic having 8 carbon atoms converted by the cyclodehydrogenation are contained in the product. A large amount can be contained.

  The catalyst used in the reforming reaction of the present invention is a mixture of zeolite and a binder (binder). The binder is a substance for enhancing the mechanical properties (strength, abrasion resistance, moldability) of the catalyst, and examples thereof include inorganic oxides such as alumina, silica, alumina boria, and silica alumina. The addition amount is added so that it may become 10 to 70 weight% in a catalyst composition. Further, for the purpose of further improving the mechanical strength of the molded body, it is also preferable to add phosphorus to these inorganic binders.

  The zeolite which is the main active component of the catalyst used in the present invention preferably has an MFI type structure which is a medium pore size zeolite in which the product aromatic hydrocarbons can enter and exit relatively freely. Specific examples of zeolite having an MFI type structure include crystalline ZSM-5 or ZSM-5 type metallosilicates. The synthesis method of ZSM-5 is disclosed in US Pat. Nos. 3,702,886 and 3,756,942. The synthesis of the ZSM-5 type metallosilicate is based on the ZSM-5 synthesis method, and can be prepared by adding nitrates or sulfates as skeleton constituent elements as raw materials.

  The zeolite having the MFI structure preferably contains one or more metals selected from gallium, zinc, iron, platinum, boron, vanadium, nickel and cobalt. Preferably, gallium and / or zinc is contained. At this time, the amount of each metal is preferably 0.1 to 10.0% by weight based on the zeolite. The metal can be contained in the zeolite by a known method such as an ion exchange method, an impregnation method, or an incipient wetness method, but it is desirable to prepare the metal so that the metal is contained in the zeolite framework. Particularly preferred zeolites are crystalline aluminogallosilicates containing 0.1 to 5.0 wt% aluminum and 0.1 to 10.0 wt% gallium in the framework structure, or 0.1 to 5 in the framework structure. Crystalline aluminodine silicate containing 0.0 wt% aluminum and 0.1-10.0 wt% zinc, or a mixture thereof. Further, when using zeolite containing gallium in the catalyst, it is desirable to perform a hydrogen treatment at 350 to 650 ° C. in advance before the reaction.

In the method for producing a high octane gasoline base material according to the present invention, a hydrocarbon mixture containing 50% by weight or more of a hydrocarbon having 4 carbon atoms is brought into contact with a zeolite catalyst. ) Content of olefin having 5 or more carbon atoms: 5 to 90% by weight
(2) Aromatic content: 10 to 90% by weight
(3) Ratio of benzene in aromatics: 10% by weight or less (4) Ratio of aromatics having 8 carbon atoms in aromatics: reformed and produced under reaction conditions of 30% by weight or more The fraction having 5 or more carbon atoms has a research octane number of 95 or more and a yield of 60% by weight or more based on the hydrocarbon mixture as a raw material.

The produced fraction having 5 or more carbon atoms is modified under the reaction conditions having the above-mentioned properties (1) to (4), whereby a low benzene content of 10% by weight or less and C8 in the aromatic It is possible to produce a gasoline base with a high C8 aromatic content of 30% by weight or higher and a high octane number of 95 or more, which is high in the research method. It becomes.
The content of the olefin having 5 or more carbon atoms in the fraction having 5 or more carbon atoms to be generated needs to be 5 to 90% by weight in order to keep the research octane number high. Further, the content of the aromatic compound needs to be 10 to 90% by weight, preferably 20 to 80% by weight in order to maintain a high yield of gasoline fraction having 5 or more carbon atoms.

  The production of the high octane gasoline base material of the present invention is achieved through the following reaction steps. When the reactants pass through the catalyst layer, dehydrogenation of saturated hydrocarbons occurs first, followed by polymerization of unsaturated hydrocarbons, followed by the olefins with a broad carbon number distribution, especially through the continuous decomposition of heavy components. Formation and subsequent cyclization dehydrogenation to aromatic hydrocarbons occurs. If the reaction temperature is too low, sufficient energy is not given to break the C—H bond of the feed hydrocarbon, resulting in a lower conversion rate of the feed hydrocarbon, resulting in a lower yield of produced gasoline, And the octane number will become low by not containing an aromatic in a product. On the other hand, if the reaction temperature is raised too much, most of the gasoline fraction in the product becomes aromatic, but unnecessary light components such as methane and ethane are largely produced by the dealkylation reaction and the overdecomposition reaction, The yield of gasoline fraction is lowered.

  The cyclization dehydrogenation reaction is an endothermic reaction, and the higher the temperature, the more generally it is advantageous for the production of aromatics having a higher octane number than the non-aromatics, but the larger the number of hydrocarbons, the more dehydrocyclization to aromatics. Because the reaction rate is high (eg, Proceedings of fifth world petroleum congress, section III, Paper 4 (1959), HG Krane) The amount of aromatics having a relatively low octane number, such as benzene, and a small number of carbon atoms can be kept low. Furthermore, for aromatics with a large carbon number of C8 or higher at higher temperatures, dealkylation reactions, especially demethylation reactions, occur, and the number of methyl substituents on the aromatic ring is smaller and the octane number is expected to be lower among aromatics. It will be converted to benzene.

  Therefore, in the reaction temperature region where aromatics are generated, the decrease in the liquid yield due to the overdecomposition reaction of hydrocarbons and the decrease in the C8 aromatic fraction due to the progress of the dealkylation reaction of the aromatic hydrocarbons are suppressed. The selection of reaction conditions is extremely important for producing a gasoline base with a high yield while maintaining a high octane number.

  The reaction temperature in the conversion of the hydrocarbon mixture of the present invention is preferably 250 to 500 ° C, more preferably 300 to 500 ° C, still more preferably 350 to 500 ° C. If the reaction temperature is less than 250 ° C, the octane number of the gasoline fraction produced with the lowering of the aromatic ratio will be low, and if it exceeds 500 ° C, the yield of the gasoline fraction having 5 or more carbon atoms will be reduced. Is not preferable because it becomes low.

  In the present invention, a high-octane gasoline with a high yield can be obtained even under atmospheric pressure, so that no high pressure is required. As the dehydrogenation reaction of the hydrocarbon raw material proceeds, under the reaction conditions, a hydrogen partial pressure corresponding to the reaction is obtained without adding hydrogen. Although intentional addition of hydrogen has the advantage of suppressing coke deposition and reducing catalyst regeneration frequency, the yield of high-octane gasoline is reduced by increasing the hydrogen partial pressure, which is not always advantageous. I can't say that. Therefore, it is desirable to suppress the hydrogen partial pressure to 1 MPa or less.

  When light gas mainly composed of methane and / or ethane recovered from the reaction product is recycled to the reaction together with a new hydrocarbon raw material, coke deposition on the catalyst is suppressed, and aromatic carbonization is performed over a long period of time. It is preferably employed because the yield of hydrogen can be kept high.

As a reaction mode carried out in the light hydrocarbon reforming reaction of the present invention, any form of a fixed bed, a moving bed or a fluidized bed can be used. Reactant flow amount in the case of a fixed bed, 10～10,000H with GHSV (gas hourly space velocity) ^-1, preferably 50～5,000H ^-1, more preferably 100～2,000H ^-1. If the GHSV is less than 10, the yield of gasoline fractions having 5 or more carbon atoms will be low, and if it is greater than 10,000, the octane number of the gasoline fraction produced as the proportion of aromatics decreases. There is a concern that will become low. When using a reaction mode other than the fixed bed, the contact time may be considered to be the same value as the fixed bed.

  The gasoline fraction having 5 or more carbon atoms produced in this way has a high research method octane number, and also has a large distillation property and is not different from commercially available gasoline. It can be blended as it is without impairing the octane number. In addition, for example, by introducing a process based on the production method of the present invention (hereinafter referred to as “this process”) after the catalytic cracking apparatus, the gasoline fraction obtained from this process becomes the gasoline obtained from the catalytic cracking apparatus. The octane number can be increased relative to the fraction, and the benzene in the gasoline blended with both can be kept at 1% by weight or less. Furthermore, since the C4 fraction generated from the catalytic cracking apparatus by this step is converted into a gasoline fraction having a higher boiling point, there is an effect of lowering the vapor pressure of gasoline when viewed with total gasoline.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[Zeolite Preparation Example 1]
Aluminosilicate (ZSM-5) was prepared by the following method.
A solution prepared by dissolving 177 g of sodium silicate in 221 g of water and a solution composed of 5.9 g of aluminum sulfate, 22 g of tetrapropylammonium bromide, 15 g of sulfuric acid, 66 g of sodium chloride, and 302 g of water were prepared. These solutions were gradually mixed at room temperature, and the mixture was stirred with a mixer for 5 minutes, then placed in a 1 L titanium beaker, mounted in an autoclave, and subjected to self-pressure at a temperature of 180 ° C. and a rotation speed of 100 rpm for 48 hours. Stir. Then, after cooling, the reaction mixture was filtered off, washed with 100 mL of water 5 times and filtered. The solid matter separated by filtration was dried at 120 ° C. and further calcined at 550 ° C. for 3 hours under air flow. The obtained powder was subjected to X-ray diffraction and confirmed to have a ZSM-5 structure. As a result of the chemical analysis, it was found that SiO ₂ / Al ₂ O ₃ (molar ratio as an oxide) was 45.

[Zeolite Preparation Example 2]
An aluminogallosilicate containing aluminum and gallium in the skeleton was prepared by the following method.
A solution consisting of 1706 g of sodium silicate and 2227 g of water, and a solution consisting of 64 g of aluminum sulfate, 36 g of gallium nitrate, 368 g of tetrapropylammonium bromide, 153 g of sulfuric acid, 653 g of sodium chloride and 2980 g of water were prepared. These solutions were gradually mixed with stirring, and the resulting mixture was stirred with a mixer to obtain a homogeneous milky liquid. This solution was put in a stainless steel autoclave and stirred at a temperature of 180 ° C. and a rotation speed of 100 rpm for 72 hours under self-pressure to carry out a crystallization operation. Next, the crystallized product was filtered and washed, and the solid was dried and calcined at 550 ° C. for 3 hours. As a result of X-ray diffraction, the obtained fired product was confirmed to have a ZSM-5 type structure. As a result of the chemical analysis, SiO ₂ / Al ₂ O ₃ , SiO ₂ / Ga ₂ O ₃ , and SiO ₂ / (Al ₂ O ₃ + Ga ₂ O ₃ ) are 70, 157 and molar ratios as oxides, respectively. It was found to be 48. Further, when X-ray diffraction analysis was performed, this zeolite was MFI structure type.

[Catalyst Preparation Example 1]
Alumina powder and water were added and kneaded as a binder to the crystalline aluminosilicate obtained in Preparation Example 1 of the zeolite, then extruded to a diameter of about 1.5 mm, dried, and calcined at 600 ° C. for 3 hours. Alumina powder was added so as to be 27% by weight based on the fired product. Subsequently, about 2N aqueous ammonium nitrate solution was added to the molded product at a rate of 5 mL / g, and ion exchange treatment was performed at 100 ° C. for 2 hours. After performing this operation four times, it was dried to obtain NH ₄ ⁺ type. Furthermore, the crystalline aluminosilicate catalyst (catalyst 1) was obtained by baking at 550 degreeC under an air flow for 3 hours.

[Catalyst Preparation Example 2]
A crystalline aluminogallosilicate catalyst (Catalyst 2) was prepared in the same manner as in Catalyst Preparation Example 1 except that the crystalline aluminogallosilicate obtained in Zeolite Preparation Example 2 was used instead of the crystalline aluminosilicate. Got.

[Examples 1-4 and Comparative Examples 1-3]
Using the catalyst obtained above, a hydrocarbon mixture shown in Table 1 diluted with an equimolar amount of nitrogen in the absence of hydrogen was used as a raw material, and a conversion reaction was carried out in a flow reactor. Prior to the reaction, as a pretreatment, only the catalyst of Preparation Example 2 was subjected to hydrogen reduction treatment at 550 ° C. for 1 hour. Then, it adjusted to predetermined reaction temperature and introduce | transduced the reaction material into the apparatus at the pressure of 1 atmosphere. The reaction conditions and reaction results are shown in Table 1.

Claims (8)

A hydrocarbon mixture containing 50% by weight or more of a hydrocarbon having 4 carbon atoms is brought into contact with a zeolite catalyst, and the produced fraction having 5 or more carbon atoms is (1) olefin content having 5 or more carbon atoms: 5 to 90 weight%
(2) Aromatic content: 10 to 90% by weight
(3) Ratio of benzene in aromatics: 10% by weight or less (4) Ratio of aromatics having 8 carbon atoms in aromatics: reformed and produced under reaction conditions of 30% by weight or more A method for producing a high-octane gasoline base material, wherein the fraction having 5 or more carbon atoms has a research octane number of 95 or more and a yield of 60% by weight or more based on a hydrocarbon mixture as a raw material.   The production method according to claim 1, wherein the hydrocarbon mixture contains 90% by weight or more of hydrocarbons having 2 to 7 carbon atoms.   The production method according to claim 1 or 2, wherein the total content of paraffin in the hydrocarbon mixture is 70% by weight or less.   The reaction temperature is 250-500 degreeC, The manufacturing method in any one of Claims 1-3 characterized by the above-mentioned.   GHSV is 10-10,000, The manufacturing method in any one of Claims 1-4 characterized by the above-mentioned.   The production method according to claim 1, wherein the zeolite has an MFI type skeleton.   The zeolite contains one or more metals selected from gallium, zinc, iron, platinum, boron, vanadium, nickel and cobalt, and the content of each metal is 0.1 to 10.0 weight with respect to the zeolite. The manufacturing method according to claim 6, wherein the manufacturing method is%. A crystalline aluminogallosilicate in which the zeolite contains 0.1 to 5.0% by weight of aluminum and 0.1 to 10.0% by weight of gallium in the framework structure, or 0.1 to 5. The production method according to claim 6 or 7, which is a crystalline aluminodine silicate containing 0% by weight of aluminum and 0.1 to 10.0% by weight of zinc, or a mixture thereof.