JP6816226B2 - Manufacturing method of reformed gasoline - Google Patents

Description

The present invention relates to a method for producing reformed gasoline. Furthermore, the present invention relates to a method for producing a gasoline base material and an aromatic hydrocarbon.

The reformed gasoline is a gasoline base material having a high octane number obtained by catalytic reforming using a catalyst, mainly using straight naphtha (SR) obtained from an atmospheric distillation apparatus (topper) as a raw material. In the catalytic reforming process, a large number of reactions occur sequentially and concomitantly to increase the octane number. It is known that reactions are roughly classified into the following (1) to (6) (for example, Non-Patent Document 1). (1) Dehydrogenation of 6-membered ring naphthen, (2) Dehydrogenation of 5-membered ring naphthen, (3) Dehydrogenation of paraffin cyclization, (4) Dehydrogenation of paraffin, (5) Hydrogen of various hydrocarbons Chemical decomposition, (6) Other reactions (cork formation, dehydrogenation, etc.).

Regarding the octane number, there are the research method octane number (RON) and the motor method octane number (MON), but in Japan, the research method octane number (hereinafter referred to as RON) is widely used. The following relationship is generally known between the structure of hydrocarbons and the octane number (for example, Non-Patent Document 2). (I) In paraffin-based hydrocarbons and olefin-based hydrocarbons, if the structure of the branches in the molecule is the same, the octane value is lower when the number of carbon atoms is larger. (Ii) In paraffin-based hydrocarbons, there is no methyl side chain. Paraffin with side chains (isoparaffin) has a higher octane value than linear paraffin (normal paraffin), (iii) Olefin-based hydrocarbons have a higher octane value than paraffin-based hydrocarbons with the same carbon number, (iv) Aroma Group hydrocarbons have the highest octane value, with RON exceeding 100. That is, normal paraffin has the lowest octane number, and aromatic hydrocarbons have the highest octane number. When a gasoline base material is mixed to obtain a gasoline product, the octane number is not strictly additive, but if a large amount of a base material having a high octane number is mixed, the octane number of the gasoline product becomes high. Therefore, it can be said that an important reaction in the catalytic reforming process is a reaction for obtaining an aromatic hydrocarbon having a high octane number from paraffinic hydrocarbons having a low octane number and naphthenes.

"Oil Refining Process" edited by the Petroleum Society, Kodansha Scientific, published on May 20, 1998. Nippon Oil Mitsubishi "Oil Handbook 2000" Fuel Oil and Fat Newspaper, published on March 1, 2000

Since reformed gasoline is rich in aromatic hydrocarbons such as benzene, toluene, and xylene (collectively referred to as BTX), the catalytic reforming process for obtaining reformed gasoline is not only used as a gasoline base material manufacturing process, but also in petrochemicals. It also occupies an important position as an aromatic hydrocarbon production process for gasoline.

An object of the present invention is to provide a method for producing reformed gasoline, which makes it possible to efficiently obtain reformed gasoline. Furthermore, an object of the present invention is to provide a method for co-producing a gasoline base material and an aromatic hydrocarbon, which makes it possible to separate and recover aromatic hydrocarbons and obtain a gasoline base material with higher efficiency.

Some of the raw materials for the catalytic reforming process contain aromatic hydrocarbons, which are the target products of the reaction. The present inventors speculate that this aromatic hydrocarbon may reduce the contact efficiency between paraffinic hydrocarbons and naphthenes and the catalyst, and may reduce the efficiency of the reaction for obtaining the aromatic hydrocarbon. The study was conducted based on. Then, the present inventors have stated that by separating aromatic hydrocarbons from the raw material oil used in the catalytic reforming process, the reactivity in catalytic reforming is improved and the conversion rate of the produced aromatic component is improved. We have found and completed the present invention.

In order to solve the above problems, the present invention uses a raw material oil containing a hydrocarbon having 6 to 10 carbon atoms and a content concentration of aromatic hydrocarbons of 1 to 30% by mass with the first composition. The first step of separating into a second composition having a higher concentration of aromatic hydrocarbons than the first composition, and the catalytic reforming of the reforming raw material oil containing the first composition are modified. Provided is a method for producing reformed gasoline, comprising a second step of obtaining a third composition having a content concentration of aromatic hydrocarbons higher than that of quality feedstock oil.

In the specification of the present application, the "reformed raw material oil" refers to the raw material oil supplied to the catalytic reforming apparatus.

According to the method for producing reformed gasoline of the present invention, by separating aromatic hydrocarbons from raw material oil, it is possible to increase the amount of raw material oil supplied to the catalytic reforming device or supply other raw material oil, and further. By reducing the concentration of aromatic hydrocarbons in the reforming raw material oil, the reactivity of catalytic reforming can be improved, and reformed gasoline can be efficiently obtained. Further, according to the method for producing reformed gasoline of the present invention, aromatic hydrocarbons useful as raw materials for chemicals can be obtained from the second composition and / or the third composition, whereby gasoline can be obtained. The base material and aromatic hydrocarbons can co-produce.

In the method for producing reformed gasoline of the present invention, a part of the above-mentioned raw material oil or another raw material oil having a boiling point of 30 ° C. or higher and 200 ° C. or lower and a content concentration of aromatic hydrocarbons of 1 to 30% by mass is used. , Can be contained in the reformed raw material oil. In the specification of the present application, the boiling point is measured by the normal pressure method of JIS K2254 petroleum product-distillation test method (corresponding international standard: ISO 3405).

In the first step, the first composition and the second composition may be obtained by one or more separation operations of distillation separation, extraction separation, membrane separation and adsorption separation.

In the first step, it is preferable to obtain the first composition and the second composition by membrane separation from the viewpoint of simplifying the step and saving energy.

In the method for producing reformed gasoline of the present invention, the content concentration of aromatic hydrocarbons in the first composition obtained in the first step is smaller than the content concentration of aromatic hydrocarbons in the raw material oil. The content concentration of aromatic hydrocarbons in the third composition obtained in the second step is preferably 50% by mass or more. In this case, since the octane number of the third composition is sufficiently high, the reformed gasoline obtained from the third composition can be used as an excellent gasoline base material.

In the method for producing reformed gasoline of the present invention, a part of the third composition can be recycled into the raw material oil. In this case, a part of the aromatic hydrocarbon produced in the reforming reaction can be contained in the second composition in the first step and separated and recovered, which is useful as a raw material for chemical products from the second composition. Aromatic hydrocarbons can also be produced together.

In the method for producing reformed gasoline of the present invention, the mixture of the second composition and the third composition is mixed with the fourth composition and the concentration of aromatic hydrocarbons higher than that of the fourth composition. A third step of separating from the fifth composition having a large amount can be further provided. In this case, the concentration of aromatic hydrocarbons in the fifth composition can be further increased, and the aromatic hydrocarbons can be recovered as useful as a raw material for chemical products. Further, the fourth composition can be used as a gasoline base material having a high octane number.

In the third step, the fourth composition and the fifth composition may be obtained by one or more separation operations of distillation separation, extraction separation, membrane separation and adsorption separation.

The present invention can provide a method for producing reformed gasoline, which makes it possible to efficiently obtain reformed gasoline. The reformed gasoline obtained by such a method can be used as a high octane gasoline base material and / or an aromatic hydrocarbon useful as a raw material for chemicals. In the method for producing reformed gasoline of the present invention, the reforming reaction is streamlined, so that aromatic hydrocarbons can be separated and recovered, and a gasoline base material having a high octane value can be obtained with high efficiency. It can be used as a co-production method for aromatic hydrocarbons.

It is a schematic diagram which shows one Embodiment of the manufacturing system which carries out the manufacturing method of reformed gasoline which concerns on this Embodiment. It is a figure which shows the outline of the membrane separation apparatus used for evaluating the separation ability of a separation membrane.

FIG. 1 shows an embodiment of a manufacturing system in which the reformed gasoline manufacturing method according to the present embodiment is implemented. The manufacturing system 100 shown in FIG. 1 is connected to a line 1 for supplying crude oil, and is connected to an atmospheric distillation apparatus 2 capable of distilling crude oil and a line 3 for supplying raw material oil from the atmospheric distillation apparatus 2. , A separating unit 10 for separating the raw material oil into the first composition and the second composition, and a reforming raw material oil containing the first composition obtained from the separating unit 10 for reforming treatment. A reforming unit 20 is provided. A line 5 for supplying the first composition taken out to the reforming part and a line 4 for taking out the second composition are connected to the separating part 10. Further, in the manufacturing system 100, a processing unit capable of performing a predetermined treatment on the second composition taken out from the separation unit 10 and the third composition obtained from the modification unit 20 as needed. 30 is provided.

A method for producing a gasoline base material and an aromatic hydrocarbon by the method for producing a reformed gasoline of the present embodiment using the production system 100 will be described.

In the method for producing reformed gasoline of the present embodiment, a raw material oil containing a hydrocarbon having 6 to 10 carbon atoms and having a content concentration of aromatic hydrocarbons of 1 to 30% by mass is used as the first composition. The first step S1 for separating into the second composition having a higher content of aromatic hydrocarbons than the first composition, and the reforming raw material oil containing the first composition are catalytically reformed. A second step S2 for obtaining a third composition having a higher content concentration of aromatic hydrocarbons than the reformed raw material oil.

Examples of the raw material oil include cracked gasoline (CCG), straight naphtha (particularly heavy naphtha: HSR) and the like.

As the heavy naphtha, as shown in FIG. 1, a fraction derived from straight naphtha obtained by subjecting crude oil to the atmospheric distillation apparatus 2 can be used. For example, a product obtained by desulfurizing the heavy component of straight naphtha or a product obtained by desulfurizing and fractional distillation of straight naphtha can be used. Further, a product obtained by desulfurizing a distillate corresponding to heavy naphtha obtained by subjecting crude oil to an atmospheric distillation apparatus can be used. Although the above desulfurization is not shown in FIG. 1, for example, a known desulfurization device can be provided after the atmospheric distillation apparatus 2 to perform the above-mentioned desulfurization on the straight naphtha fraction obtained by atmospheric distillation. .. As a desulfurization method, for example, in the presence of hydrogen, a straight-running naphtha has a reaction temperature of 280 to 350 ° C., a hydrogen partial pressure of 0.5 to 10 MPaG, an LHSV of 1.0 to 8.0 h-1, and a hydrogen / oil ratio. A method of contacting with a hydrorefining catalyst at 10 to 150 NL / L can be mentioned.

As the hydrogenation purification catalyst, a catalyst in which an element of Group 6 of the Periodic Table of the Elements and an element of Group 9 or Group 10 are supported on an inorganic porous oxide carrier such as alumina, silica, or silica-alumina can be used. .. Molybdenum and tungsten can be used as the elements of Group 6 of the Periodic Table of the Elements. Cobalt can be used as the Group 9 element. Nickel can be used as the Group 10 element.

In the present embodiment, it is preferable to use desulfurized direct distilling heavy naphtha having a 5% distilling temperature of 75 to 115 ° C. and a 95% distilling temperature of 120 to 170 ° C., and a 5% distilling temperature of 85. It is more preferable to use desulfurized direct distilling heavy naphtha having a temperature of about 110 ° C., particularly 95 to 105 ° C., and a 95% distillation temperature of 125 to 160 ° C., particularly 135 to 150 ° C. When the 5% distillation temperature is 75 ° C. or higher, a large amount of naphtha having 6 or more carbon atoms is contained, and catalytic reforming can be efficiently performed in the catalytic reforming apparatus. When the 95% distillation temperature is 120 ° C. or higher, the proportion of naphthenic acid contained in the raw material naphtha fraction increases, and catalytic reforming can be efficiently performed in the catalytic reforming apparatus. On the other hand, when the 95% distillation temperature is 170 ° C. or lower, there is little possibility that sulfur and nitrogen, which adversely affect the reforming reaction catalyst, are contained.

The catalytic cracking gasoline is not particularly limited in terms of the processes (contact cracking apparatus, raw material oil for catalytic cracking, catalytic cracking catalyst, operating conditions, etc.), and catalytic cracking gasoline obtained in any known manufacturing process is used. Can be done. The catalytic cracking device uses a catalyst such as amorphous silica alumina or zeolite to distill petroleum from light oil to reduced pressure light oil, while delightening oil obtained from a heavy oil indirect cracking device, and direct cracking obtained from a heavy oil direct desulfurization device. It is a device that obtains a high octane gasoline base material by catalytic cracking of deweighted oil, atmospheric residual oil, etc. For example, the UOP catalytic cracking method, the flex cracking method, the ultra-orthoflow method, the fluidized catalytic decomposition method such as the Texaco fluidized catalytic decomposition method, the residual oil fluidized catalytic decomposition method such as the RCC method and the HOC method described in Non-Patent Document 1. Processes such as are known.

In the manufacturing system 100 shown in FIG. 1, the catalytic cracking gasoline obtained by the distillation column 12 connected to the atmospheric distillation apparatus 2 and the fluid cracking apparatus 14 can be supplied from the line 15 to the separation unit 10.

As the catalytic cracking gasoline, light cracking gasoline having a boiling point range of about 30 to 100 ° C. or heavy catalytic cracking gasoline having a boiling point range of about 100 to 200 ° C. can be used.

In the present embodiment, it is preferable to use catalytically cracked gasoline having a 5% distillation temperature of 80 ° C. or higher and a 95% distillation temperature of 180 ° C. or lower, and a 5% distillation temperature of 90 ° C. or higher, particularly 95 ° C. As described above, it is more preferable to use catalytically cracked gasoline having a 95% distillation temperature of 160 ° C. or lower, particularly 150 ° C. or lower. When the 5% distillation temperature is 80 ° C. or higher, a large amount of hydrocarbons having 6 or more carbon atoms are contained, and catalytic reforming can be efficiently performed in the catalytic reforming apparatus. On the other hand, when the 95% distillation temperature is 180 ° C. or lower, there is little possibility that sulfur and nitrogen, which adversely affect the reforming reaction catalyst, are contained.

In the present embodiment, a refined naphtha fraction having a sulfur content of 1 ppm or less obtained by further hydrogenating catalytic cracked gasoline can be used. As the hydrogenation treatment, the catalytic cracking gasoline distillate is subjected to a reaction temperature of 280 to 350 ° C., a hydrogen partial pressure of 0.5 to 10 MPaG, an LHSV of 1.0 to 8.0 h-1, and a hydrogen / oil ratio in the presence of hydrogen. There is a method of contacting with a hydrogenation purification catalyst at 10 to 150 NL / L. As the hydrogenation purification catalyst, a catalyst in which an element of Group 6 of the Periodic Table of the Elements and an element of Group 9 or Group 10 are supported on an inorganic porous oxide carrier such as alumina, silica, or silica-alumina can be used. .. Molybdenum and tungsten can be used as the elements of Group 6 of the Periodic Table of the Elements. Cobalt can be used as the Group 9 element. Nickel can be used as the Group 10 element.

The raw material oil preferably has an aromatic hydrocarbon content of 1 to 30% by mass, preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and even more preferably 15 to 25% by mass.

The raw material oil preferably has a sulfur content of 5 mass ppm or less, more preferably 1 mass ppm or less, and further preferably 0.5 mass ppm or less. Sulfur content means the mass of sulfur in a compound containing a sulfur atom. In the specification of the present application, the method for measuring sulfur content is JIS K2541-2 crude oil and petroleum products-sulfur content test method Part 2: Trace coulometric titration method.

As the separation unit 10, one capable of performing one or more separation operations of distillation separation, extraction separation, membrane separation and adsorption separation can be used.

In the present embodiment, it is preferable that the separation unit 10 is a membrane separation from the viewpoint of simplifying the process and saving energy. In this case, the membrane separation is preferably one that does not require an operation of desorbing the adsorbent as in the case of adsorption separation.

As the membrane for membrane separation in the separation unit 10, a membrane capable of selectively permeating aromatic hydrocarbons is desirable. This separation membrane selectively adsorbs molecules with a large adsorptive power, and molecules with a large adsorptive power permeate, and molecules with a small adsorbent power are blocked by the adsorbed molecules and do not permeate. Aromatic hydrocarbons can be selectively separated because they have a large adsorptive power due to the π atom of the aromatic ring. Since the separation membrane that separates molecules by the adsorption force between the separation membrane and the molecule separates by chemical properties, it has a characteristic that even a molecule having a large minimum diameter of a molecule such as an aromatic hydrocarbon can permeate. Preferred separation membranes include zeolite membranes.

As the above-mentioned inorganic film, one in which a film material is formed on the surface of the porous support or inside the pores can be used. Further, as the porous support, one having high mechanical strength in terms of physical properties can be appropriately selected depending on the environment at the time of production such as the synthetic temperature of the membrane, the operating temperature of the membrane and other usage conditions. From the viewpoint of heat resistance, acid resistance and the like, a porous support made of ceramics is preferable, a porous support made of alumina is more preferable, and a porous support made of α-alumina is more preferable.

Currently known synthetic zeolite can be applied as the zeolite constituting the zeolite membrane. For example, the zeolite described in "Science and Engineering of Zeolites" edited by Yoshio Ono and Tatsuaki Yashima, Kodansha Scientific (issued on July 10, 2000) can be applied. Specific examples thereof include A-type zeolite (LTA), faujasite-type zeolite (FAU), mordenite-type zeolite (MOR), and ZSM-5-type zeolite (MFI). Faujasite-type zeolite is preferable, and examples of the faujasite-type zeolite include X-type zeolite and Y-type zeolite.

The zeolite membrane may be a FAU type zeolite membrane because it has a large adsorption force with aromatic hydrocarbons and the micropore diameter of the zeolite is large. The FAU-type zeolite membrane is a separation membrane composed of FAU-type zeolite. Examples of the FAU-type zeolite include X-type zeolite (Si / Al ratio of 1.0 to 1.5) and Y-type zeolite (Si / Al ratio of 1.5 or more). The upper limit of the Si / Al ratio of the Y-type zeolite is not limited, but is preferably 11 or less, more preferably 6 or less, and particularly preferably 3 or less. Further, the FAU-type zeolite may contain a metal element other than Si and Al. Examples of the metal element include Li, Na, K, Ca, Mg, Ba, Ni, Ag, Cu and Pd, of which alkali metals (Li, Na and K) are preferable.

Hydrothermal synthesis can be mainly used for the synthesis of the zeolite membrane. In hydrothermal synthesis, various zeolites are synthesized by selecting various starting substances and their blending amounts, and further selecting hydrothermal conditions. Prior to the synthesis of the zeolite membrane on the surface of the porous support, it is preferable to support the zeolite particles on the surface including the pores on the surface side of the porous support. In order to support the zeolite particles in this way, a method of dry-polishing the surface of the porous support using zeolite particles, a dipping method of immersing the zeolite particles in a suspension dispersed in a dispersion medium, and a dip coating method. , A method in which a suspension in which zeolite particles are dispersed in a dispersion medium is brush-coated on the surface of the support and the like can be mentioned. Examples of the zeolite particles to be supported include those containing X-type zeolite and / or Y-type zeolite as main components.

When the zeolite membrane is hydrothermally synthesized after supporting the zeolite particles on the surface of the porous support in this way, the zeolite particles that serve as seed crystals for the synthesis of the zeolite membrane are densely porous. It can be present on the surface of the material. As a result, the polycrystals to be synthesized are also densely synthesized on the base material according to the presence state of these seed crystals. Therefore, pinholes and crystal gaps are unlikely to be formed, and the surface of the porous support is covered with a continuous polycrystalline film.

The shape of the separation membrane is not particularly limited, and may be, for example, a flat membrane shape, a tubular shape, a cylindrical shape, a hollow thread shape, a monolith shape, a honeycomb shape, a spiral shape, or the like. The thickness of the film is not particularly limited, but the film thickness can be set in the range of about 1 to 100 μm in order to improve the permeability.

The inorganic film has a separation coefficient of aromatic hydrocarbons with respect to non-aromatic hydrocarbons preferably 2 or more, more preferably 10 or more, and even more preferably 100 or more.

In the present specification, the separation coefficient of the component A of the inorganic membrane with respect to the component B is defined by the following formula as the ratio of the component A (mol%) on the supply side to the component B (mol%) on the transmission side. The value of the ratio of component B (mol%) to component B (mol%).
Separation coefficient of component A with respect to component B = (Pa / Pb) / (Fa / Fb)
Pa: Mol concentration of component A on the transmission side, Pb: mol concentration of component B on the transmission side, Fa: mol concentration of component A on the supply side, Fb: mol concentration of component B on the supply side

As a means for membrane separation, a known membrane separator can be used. For example, in the case of a membrane separator in which a separation membrane is formed on the outer circumference of a tubular support, raw material oil is introduced from one outer end of the membrane separator, a non-permeable component is taken out from the other end, and permeated from the inside of the support. Ingredients can be taken out.

The separation operation by the membrane is a vapor permeation method in which both sides of the supply side and the permeation side are vapor phases, a permeation vaporization method in which the supply side is a liquid phase and the permeation side is a vapor phase, and the supply side and the permeation side are separated. Any method of the liquid phase method in which both sides are liquid phases may be adopted. In the present embodiment, since the permeation flow velocity of the substance is proportional to the partial pressure difference between the substances on the supply side and the permeation side, the vapor permeation method is preferable from the viewpoint that the partial pressure on the supply side can be easily increased.

The separation operation temperature is not particularly limited, but a suitable temperature can be set from the permeation rate and the separation coefficient, and is preferably 70 to 500 ° C. In order to perform membrane separation, it is necessary that the partial pressure of the permeable substance on the non-permeable side (raw material side) is higher than the partial pressure of the permeable substance on the permeable side. Therefore, by a known method, (a) the pressure on the non-permeation side is raised above the atmospheric pressure, (b) the pressure on the permeation side is lower than the atmospheric pressure, and (c) the sweep gas (also referred to as carrier gas) on the permeation side. ) Is flowed to reduce the partial pressure of the permeating substance on the permeation side, so that the membrane can be separated. Two or more of the above operations (a) to (c) may be used in combination. The pressures on the non-transmissive side and the permeation side are not particularly limited, but a suitable range can be set from the permeation rate and the separation coefficient. For example, the absolute pressure on the non-permeate side is 101 to 2100 kPa. The absolute pressure on the transmission side can be set to less than 101 kPa.

Examples of the extraction separation include a solvent extraction process and an extraction distillation process, but the apparatus and conditions are not particularly limited, and any known process can be adopted. The solvent extraction process is a process in which a solvent is mixed with a mixed liquid consisting of a large number of components and separated by utilizing the difference in solubility in the solvent. As the solvent to be used, for example, sulfolane, dimethyl sulfoxide, N-methyl-2-pyrrolidone and the like can be used. Typical processes include, for example, the Sulfolane process and the Arosolvan process described in Non-Cited Document 1. In the extraction distillation process, the raw material and the solvent come into contact with each other in the extraction distillation column, aromatic hydrocarbons are extracted into the solvent to form a column bottom fraction, and at the same time, non-aromatics are separated as a column top fraction by distillation. As the solvent to be used, the same solvent as the above-mentioned solvent extraction process can be used, and typical processes include, for example, the Distapex process and the Morphylane process described in Non-cited Document 1.

The apparatus and conditions are not particularly limited as the adsorption separation, and any known process can be adopted. The adsorption separation process is a process in which a mixture composed of a large number of components is introduced into an adsorption layer and separated by utilizing the difference in affinity for an adsorbent. As the adsorbent to be used, a molecular sieve or the like can be used, and typical processes include, for example, the Parex process and the Aromax process described in Non-cited Document 1.

In the present embodiment, the content concentration of aromatic hydrocarbons in the first composition obtained in the first step may be lower than the content concentration of aromatic hydrocarbons in the raw material oil. From the viewpoint of further improving the reaction efficiency in the second step, it is preferable to separate the raw material oil so that the content is preferably 10% by mass or less, more preferably 5% by mass or less. In particular, when the content concentration of aromatic hydrocarbons in the raw material oil exceeds 10% by mass, it is preferable to separate the raw material oil so that the content concentration of aromatic hydrocarbons in the first composition is within the above range.

The content concentration of aromatic hydrocarbons in the second composition obtained in the first step is preferably 70% by mass or more, more preferably 90% by mass or more.

In the present embodiment, a part of the third composition can be recycled into the feedstock oil via the line 18. In this case, a part of the aromatic hydrocarbons produced in the reforming reaction can also be separated and recovered in the first step (separation unit 10). In the present embodiment, the second composition can be recovered via the line 4.

In the reforming section 20, catalytic reforming of the reforming raw material oil containing the first composition is performed. The catalytic reforming apparatus and operating conditions for performing catalytic reforming are not particularly limited, and any known manufacturing apparatus and operating conditions can be adopted. Examples of the catalytic reformer include a platinum alumina catalyst and a bimetallic alumina catalyst in which a second metal such as rhenium, germanium, tin, or iridium is added to platinum. As such an apparatus, for example, a desulfurized straight distillate heavy naphtha having a boiling point range of about 80 to 180 ° C. is treated to carry out aromatic hydrocarbons such as reformate, benzene, toluene and xylene, which are high octane gasoline base materials. Widely used devices can be used to obtain hydrogen. For example, there are a UOP platforming process, a reniforming process, an ERE power forming process, a Magna forming process, etc. described in Non-Patent Document 1.

The reaction temperature is preferably 400 to 600 ° C, more preferably 450 to 550 ° C. The LHSV (liquid space velocity) is preferably 0.5 to 5h-1, more preferably 1 to 2h-1. The reaction pressure is preferably 0.1 to 2 MPa, more preferably 0.2 to 1.5 MPa. The hydrogen / oil ratio (molar ratio) is preferably 0.5 to 10, and more preferably 1 to 5.

In the present embodiment, from the viewpoint that the obtained reformed gasoline can be applied as an excellent gasoline base material, the content concentration of aromatic hydrocarbons in the third composition obtained in the second step is 50% by mass. It is preferably 70% by mass or more, more preferably 80% by mass or more, and particularly preferably 80% by mass or more.

In the present embodiment, a part of the raw material oil or another raw material oil having a boiling point of 30 ° C. or higher and 200 ° C. or lower and a content concentration of aromatic hydrocarbons of 1 to 30% by mass is used as the modified raw material. It can be contained in oil. For example, in the manufacturing system 100 shown in FIG. 1, a part of the raw material oil can be contained in the modified raw material oil via the line 17. Further, when other raw material oils are contained, the cracked cracking gasoline described above can be contained in the modified raw material oil via the line 16.

The reformed gasoline can be obtained through the reforming section 20, but in the present embodiment, the second composition and the third composition are described from the viewpoint of co-producing the gasoline base material and the aromatic hydrocarbon. A third step of separating the mixture of the two into a fourth composition and a fifth composition having a higher concentration of aromatic hydrocarbons than the fourth composition can be further provided. In this case, the processing unit 30 shown in FIG. 1 can be used as a separation unit for carrying out the above steps, and the fourth composition and the fifth composition can be taken out from lines 7 and 8, respectively. The fourth composition can be obtained as a gasoline base material, and the fifth composition can be obtained as an aromatic hydrocarbon useful as a raw material for a chemical product. The second composition can be mixed with the third composition via the line 4 (dashed line).

The separation unit may have the same configuration as the separation unit 10 described above, but may be separated by distillation.

In the present embodiment, the content concentration of aromatic hydrocarbons in the fifth composition is preferably 90% by mass or more, and more preferably 95% by mass or more.

The gasoline base material obtained by the method according to the present embodiment has a sulfur content of 5 mass ppm or less, preferably 1 mass ppm or less, more preferably 0.5 mass ppm or less, and particularly preferably 0.1 mass ppm or less. Is preferable. When the sulfur content is 5 mass ppm or less, it becomes easy to maintain the flexibility when mixing with another gasoline base material to produce a gasoline composition. The nitrogen content of the gasoline base material is preferably 1 mass ppm or less, more preferably 0.5 mass ppm or less. The RON of the gasoline base material is preferably 100 or more, more preferably 102 or more, and even more preferably 104 or more. When the RON is 100 or more, it becomes easy to maintain the flexibility when the gasoline composition is produced by mixing with other gasoline base materials.

The aromatic hydrocarbon obtained by the method according to the present embodiment preferably has a nitrogen content of 1 mass ppm or less, more preferably 0.5 mass ppm or less. When the nitrogen content is 1 mass ppm or less, the possibility of adversely affecting the process of obtaining a higher value-added aromatic hydrocarbon is reduced.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

[Evaluation of separation ability of separation membrane]
(Membrane separation device)
The membrane separation device shown in FIG. 2 was prepared, and the separation ability of the separation membrane was evaluated using this. The apparatus of FIG. 2 is a raw material supply unit including a membrane separation cell 54 capable of accommodating the separation membrane 55, a supply tank 50a for supplying raw materials to the membrane separation cell 54 via a supply line 53 having a preheater, and a pump 50b. 51, a supply cylinder 52 connected to the membrane separation cell 54 and supplying a sweep gas of a permeation component, a heater 56 for heating the membrane separation cell 54, and a non-permeability component for taking out the non-permeate component from the membrane separation cell 54. A non-permeated gas line 57 and a permeated gas line 58 for extracting a permeated component from the membrane separation cell 54 are provided.

In this device, the raw material can be supplied to the membrane separation cell 54 while being vaporized by the supply line 53 having a preheater. In addition, the components obtained from the non-permeated gas line 57 and the permeated gas line 58 can be collected in a recovery tank cooled by liquid nitrogen, and analyzed by a gas chromatograph.

(Separation membrane)
Zeolite particles are dip-coated on the outer surface of a tubular support (30 mm × 10 mmφ, thickness 1 mm) made of porous alumina, and the support is covered with water glass, sodium aluminate, and deionized water. A NaY-type zeolite membrane element having a membrane area of 0.00094 m2 was prepared by immersing in the containing solution and performing hydrothermal treatment at 60 ° C. for 24 hours with stirring. This NaY-type zeolite membrane element was installed as a separation membrane in the apparatus shown in FIG. 2 and an evaluation test was conducted. The effective area of the membrane after installation was 0.00063m2.

A hydrocarbon composition having the composition shown in Table 1 was placed in a supply tank 50a as a supply raw material, and was supplied at 0.3 g / min into a membrane separation cell 54 held at atmospheric pressure while being vaporized by a supply line 53. The temperature of the separation membrane was set to 150 ° C. by the heater 56, helium gas was flowed as a carrier gas at a rate of 300 mL / min, and the permeated gas was collected in a recovery tank cooled by liquid nitrogen and analyzed by a gas chromatograph. .. At this time, the pressure on the non-permeated side was atmospheric pressure (101 kPa), and the partial pressure of the hydrocarbon on the permeated side was 0.2 kPa. Table 2 shows the transmittances (mol, m-2, s-1, Pa-1) of the components of each compound at this time. Table 3 shows the separation coefficients of the predetermined compound (component A) at this time with respect to the predetermined compound (component B). The separation coefficient of the component A with respect to the component B is the component A (mol%) in the permeated gas with respect to the ratio of the component A (mol%) and the component B (mol%) in the feedstock defined by the following formula. It was calculated from the value of the ratio with the component B (mol%).
Separation coefficient of component A with respect to component B = (Pa / Pb) / (Fa / Fb)
Pa: Mol concentration of component A in permeated gas Pb: mol concentration of component B in permeated gas Fa: mol concentration of component A in feedstock Fb: mol concentration of component B in feedstock

[Manufacturing of reformed gasoline]

(Example 1)
A simulation of supplying the raw material naphtha A (Table 4) having the same composition as the heavy naphtha fraction obtained from the atmospheric distillation apparatus to the separation membrane was performed based on the separation results (transmittance and separation coefficient) obtained by the separation membrane. went. At this time, the separated naphtha B was obtained by separating an amount corresponding to 90% by mass of the aromatic fraction contained in the raw material naphtha A. Using the obtained separated naphtha B as a reforming raw material oil, a simulation was performed on the reaction of obtaining a reforming product C by the following catalytic reforming.
Supply of reforming feedstock: 117.6 ton / h
Reaction temperature: 490 ° C
Reaction pressure: 0.42 MPaG
LHSV: 1.7h-1
Hydrogen / hydrocarbon molar ratio: 1.7

Table 4 shows the compositions of naphtha B and modified product C after separation obtained by calculation. Further, a simulation was also carried out for a reaction in which the raw material naphtha A was used as the modified raw material oil and the modified product D was obtained under the same conditions as described above. The calculation results are shown in Table 4.

When the naphtha B was modified after separation, the amount of increase in the aromatic content (aromatic content in the modified product-aromatic content in the modified raw material) was 67.3 ton / h, and the raw material naphtha A was used. It increased by 9.6 ton / h as compared with 57.7 ton / h when modified. Further, when the naphtha B was modified after separation, the conversion rate from non-aromatic component to aromatic component and the conversion rate from linear hydrocarbon to aromatic component were 58.3% and 84.3%, respectively. It was higher than 57.6% and 83.2% when the raw material naphtha A was modified.

These results indicate that the separation of aromatic hydrocarbons from the reforming feedstock improved the reactivity in catalytic reforming, leading to an increase in the aromatic content produced.

1,3,4,5,6,7,8,11,13,15,16,17,18 ... line, 2 ... atmospheric distillation apparatus, 10 ... separation part, 12 ... distillation column, 14 ... fluid cracking Equipment, 20 ... Modification unit, 30 ... Processing unit, 50a ... Supply tank, 50b ... Pump, 51 ... Raw material supply unit, 52 ... Supply cylinder, 53 ... Supply line, 54 ... Membrane separation cell, 55 ... Separation membrane, 56 ... heater, 57 ... non-permeable gas line, 58 ... permeated gas line, 100 ... manufacturing system.

Claims (4)

Raw material oils containing hydrocarbons having 6 to 10 carbon atoms and having an aromatic hydrocarbon content of 1 to 30% by mass are used in the first composition and more aromatic hydrocarbons than the first composition. The first step of separating into the second composition having a large content concentration, and
A second step of catalytically reforming the reformed raw material oil containing the first composition to obtain a third composition having a higher concentration of aromatic hydrocarbons than the modified raw material oil.
With
The reforming feedstock, containing catalytically cracked gasoline,
A method for producing reformed gasoline, wherein in the first step, the first composition and the second composition are obtained by one or more separation operations of extraction separation, membrane separation and adsorption separation . A claim that a part of the raw material oil or another raw material oil having a boiling point of 30 ° C. or higher and 200 ° C. or lower and a content concentration of aromatic hydrocarbons of 1 to 30% by mass is contained in the modified raw material oil. Item 2. The method for producing reformed gasoline according to Item 1. The method for producing modified gasoline according to claim 1 or 2 , wherein in the first step, the first composition and the second composition are obtained by membrane separation. The content concentration of aromatic hydrocarbons in the first composition obtained in the first step is smaller than the content concentration of aromatic hydrocarbons in the raw material oil.
The method for producing reformed gasoline according to any one of claims 1 to 3 , wherein the content concentration of aromatic hydrocarbons in the third composition obtained in the second step is 50% by mass or more.

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