CN107974295B

CN107974295B - Gasoline treatment method

Info

Publication number: CN107974295B
Application number: CN201610921993.5A
Authority: CN
Inventors: 刘秀良; 许友好; 王新
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2016-10-21
Filing date: 2016-10-21
Publication date: 2020-03-24
Anticipated expiration: 2036-10-21
Also published as: CN107974295A

Abstract

The invention relates to a treatment method of gasoline, which comprises the following steps: cutting a gasoline raw material to obtain a light gasoline fraction and a heavy gasoline fraction; carrying out etherification treatment on the obtained light gasoline fraction to obtain etherified oil; feeding the obtained heavy gasoline fraction into a fluidized reactor to contact with a mixed catalyst and carrying out desulfurization and aromatization reactions under the hydrogen condition to obtain a heavy gasoline product; wherein the mixed catalyst comprises an adsorption desulfurization catalyst and an olefin aromatization catalyst. The method provided by the invention can reduce the contents of sulfur and olefin in the gasoline, and can simultaneously maintain the octane number of the gasoline and the yield of the gasoline.

Description

Gasoline treatment method

Technical Field

The invention relates to a method for treating gasoline.

Background

Air pollution caused by automobile exhaust emission is increasingly serious. With increasing attention of people on environmental protection, China speeds up the pace of upgrading the quality of automotive fuel, and the national standard GB17930-2013 requires that the sulfur content in gasoline is not more than 10 mu g/g and the volume fraction of olefin is not more than 24%.

The catalytic cracking gasoline is the main component of the motor gasoline in China, accounts for about 75% in a gasoline pool, and is characterized by having higher contents of olefin and sulfur. It is not difficult to realize deep desulfurization of gasoline and reduce the content of olefin in catalytically cracked gasoline by adopting a hydrogenation technology, but because olefin is a high-octane component, the great reduction of the content of olefin causes serious loss of the gasoline octane number, thereby affecting the automotive performance of gasoline and the economic benefit of a refinery, and therefore, the deep desulfurization of gasoline is realized while the gasoline octane number is kept to be a hotspot of clean gasoline production in China.

At present, the deep desulfurization of gasoline mainly adopts a hydrodesulfurization method or an adsorption desulfurization method.

Selective hydrodesulfurization is one of the main modes for removing thiophene sulfides at present, but the reactions such as olefin saturation and the like also occur in large quantity, so that the octane number loss is large. In addition, a deep hydrogenation method for recovering octane number is also accepted, and a second reactor is arranged to promote cracking, isomerization and alkylation reactions of hydrocarbons with low octane number while deep desulfurization and olefin saturation are carried out, so that the aim of recovering octane number is fulfilled. Chinese patent CN101845322A discloses a method for reducing sulfur and olefin content in gasoline, the raw material catalytically cracked gasoline is first passed through a prehydrogenation reactor to remove diolefin, then is passed through a fractionating tower to be cut and fractionated into light gasoline and heavy gasoline, the light gasoline is undergone the process of hydrodesulphurization by hydrogen adsorption, the heavy gasoline is passed through a selective hydrogenation reactor to undergo hydrodesulfurization, the reaction effluent is passed through a hydro-upgrading reactor to undergo hydro-upgrading so as to reduce olefin content, and the heavy gasoline after being upgraded is blended with light gasoline adsorption desulfurization product to obtain the clean gasoline meeting the standard requirements. Although the adsorption desulfurization catalyst has a good effect of removing sulfides in gasoline, the adsorption desulfurization is carried out in the presence of hydrogen, olefins in the catalytic cracking gasoline can be saturated, especially light gasoline is subjected to adsorption desulfurization, and the octane number of olefin components in the light gasoline is high, so that the octane number of the gasoline is greatly lost.

The adsorption process for removing sulfur-containing compound from fuel oil is to use adsorbent to make hydrogen reaction adsorption on light oil to produce metal sulfide or to use sulfide polarity to remove sulfur, so that it has low hydrogen consumption and high desulfurizing efficiency, and can produce gasoline with sulfur content below 10 microgram/g. Although the adsorption process realizes deep desulfurization of gasoline under the condition of low hydrogen consumption, the octane number of the gasoline product is still slightly lost. Especially when processing gasoline feedstocks having high olefin content and high sulfur content, still results in a large loss in gasoline octane number.

For most catalytic cracking units, it is an effective method to use a catalyst or promoter containing a molecular sieve having an MFI structure in order to increase the production of propylene and butene and to increase the octane number of gasoline. U.S. Pat. No. 3,403,403,403 shows that the addition of ZSM-5 molecular sieve to the catalytic cracking catalyst can improve the octane number of gasoline and increase the yield of C3-C4 olefins. However, as is known to those skilled in the art, increased propylene and butylene production comes at the expense of gasoline production.

Aromatization of low-carbon alkane is an effective method for improving the utilization value of the low-carbon alkane. A great deal of research is carried out on the aromatization process taking molecular sieves with high silica-alumina ratio as catalysts, particularly on the process taking ZSM-5, ZSM-11 and ZSM-21 molecular sieves as catalysts, and the zeolite with an MFI structure is used for aromatization of low-carbon hydrocarbons produced from coking or pyrolysis gasoline.

Disclosure of Invention

The invention aims to provide a method for treating gasoline, which can reduce the contents of sulfur and olefin in the gasoline, and can simultaneously maintain the octane number of the gasoline and the high gasoline yield.

In order to achieve the above object, the present invention provides a method for treating gasoline, comprising: cutting a gasoline raw material to obtain a light gasoline fraction and a heavy gasoline fraction; carrying out etherification treatment on the obtained light gasoline fraction to obtain etherified oil; feeding the obtained heavy gasoline fraction into a fluidized reactor to contact with a mixed catalyst and carrying out desulfurization and aromatization reactions under the hydrogen condition to obtain a heavy gasoline product; wherein the mixed catalyst comprises an adsorption desulfurization catalyst and an olefin aromatization catalyst.

Preferably, the method further comprises: and mixing the obtained etherified oil and the heavy gasoline product to obtain a gasoline product.

Preferably, the volume fraction of olefins in the gasoline feedstock is greater than 20% by volume.

Preferably, the sulfur content of the gasoline raw material is more than 10 mu g/g.

Preferably, the gasoline feedstock is at least one selected from the group consisting of catalytically cracked gasoline, coker gasoline, thermally cracked gasoline, and straight run gasoline.

Preferably, the cut points of the light gasoline fraction and the heavy gasoline fraction are in the range of 60 to 80 ℃.

Preferably, the step of etherification treatment comprises: contacting said light gasoline fraction with an alcohol,carrying out etherification reaction on the olefin in the light gasoline fraction and alcohols under the action of an etherification catalyst to obtain etherified oil; wherein the temperature of the etherification reaction is 20-200 ℃, the pressure is 0.1-5MPa, and the weight hourly space velocity is 0.1-20 hours^-1The molar ratio of the alcohols to the light gasoline fraction is 1: (0.1-100), wherein the etherification catalyst comprises at least one selected from the group consisting of resins, molecular sieves, and heteropolyacids.

Preferably, the fluidization reactor is a riser reactor and/or a dense phase fluidized bed reactor.

Preferably, the adsorption desulfurization catalyst contains silica, alumina, zinc oxide, and a desulfurization active metal which is at least one selected from the group consisting of cobalt, nickel, copper, iron, manganese, molybdenum, tungsten, silver, tin, and vanadium.

Preferably, the adsorption desulfurization catalyst contains 10-90 wt% of zinc oxide, 5-85 wt% of silicon dioxide and 5-30 wt% of aluminum oxide, based on the dry weight of the adsorption desulfurization catalyst and the weight of oxides; the content of the desulfurization active metal in the adsorption desulfurization catalyst is 5-30 wt% based on the dry weight of the adsorption desulfurization catalyst and calculated by the weight of elements.

Preferably, the olefin aromatization catalyst comprises on a dry basis and based on the total weight of the olefin aromatization catalyst, 10 to 30 weight percent of a molecular sieve, 0 to 20 weight percent of an aromatization active metal oxide and 50 to 90 weight percent of a support; the carrier comprises a carrier body and an aromatization active metal, wherein the carrier body comprises a carrier body and a carrier body, the carrier body comprises a carrier body, the carrier body is arranged on the carrier body, the carrier body comprises a carrier body, and the carrier body comprises a carrier body, a carrier body and a carrier body, the carrier body is arranged on the carrier body, the carrier body is arranged on.

Preferably, the MFI structure molecular sieve is at least one selected from ZSM-5, ZSM-8 and ZSM-11, and the aromatization active metal is at least one selected from Fe, Zn and Ga.

Preferably, the proportion of the olefin aromatization catalyst in the mixed catalyst is from 1 to 30% by weight.

Preferably, the conditions of the desulfurization and aromatization reactions include: the reaction temperature is 350-500 ℃, and the weight hourly space velocity is 2-50 h^-1The reaction pressure is 0.5-3.0MPa, and the volume ratio of hydrogen to heavy gasoline fraction is 1-500.

Preferably, the method further comprises: and (2) pretreating the light gasoline fraction and then performing etherification treatment, wherein the pretreatment is at least one selected from alkali liquor extraction treatment, mercaptan conversion treatment and selective hydrogenation treatment.

Compared with the prior art, the invention has the following technical effects:

1. the method cuts the gasoline raw material with high sulfur and high olefin content into light gasoline fraction and heavy gasoline fraction, and carries out desulfurization and aromatization reaction on the heavy gasoline fraction, the adsorption desulfurization catalyst and the olefin aromatization catalyst, and can aromatize olefin in the gasoline while reducing the sulfur content of the gasoline, thereby reducing the olefin content in the gasoline, maintaining the octane number of the gasoline and the high yield of the gasoline raw material, and being capable of directly producing national V or even national VI grade gasoline.

2. The desulfurization and aromatization reactions of the invention are carried out in a fluidized reactor by adopting two catalysts, thereby not only improving the reaction efficiency, but also reducing the investment cost without increasing or changing the reactor.

3. The method of the invention can also reduce light components in the gasoline product and reduce the vapor pressure of the gasoline.

4. The invention carries out etherification treatment on the light gasoline fraction, can reduce the olefin in the light gasoline fraction, can also produce high-octane etherified oil and improves the octane number of gasoline products.

5. The desulfurization and aromatization reactions of the invention are carried out in a fluidized reactor by adopting two catalysts, which can avoid the need of adding an aromatization reactor and an auxiliary system separately in a gasoline step-by-step treatment method (gasoline desulfurization first and aromatization later, or gasoline aromatization first and desulfurization later), and can also avoid the need of changing the preparation process flow and the catalyst abrasion strength of the existing adsorption desulfurization catalyst and aromatization catalyst by using a gasoline desulfurization and aromatization coupling catalyst, thereby not only improving the reaction efficiency, but also reducing the investment cost.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is a schematic flow diagram of one embodiment of the process of the present invention.

Description of the reference numerals

1 gasoline feed 2 fractionating column 3 heavy gasoline fractions

4 hydrogen 5 fluidized reactor 6 desulfurization and aromatization products

7 high pressure separator 8 tail gas 9 heavy gasoline product

10 light gasoline fraction 11 pretreatment unit 12 light gasoline before etherification

13 methanol 14 etherification device 15 etherification product

16 fractionating tower 17 methanol-containing tail gas 18 etherified oil

19 Mixer 20 gasoline product

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The RIPP test method can be found in petrochemical analysis, Yangcui and other editions, 1990 edition.

The invention provides a treatment method of gasoline, which comprises the following steps: cutting a gasoline raw material to obtain a light gasoline fraction and a heavy gasoline fraction; carrying out etherification treatment on the obtained light gasoline fraction to obtain etherified oil; feeding the obtained heavy gasoline fraction into a fluidized reactor to contact with a mixed catalyst and carrying out desulfurization and aromatization reactions under the hydrogen condition to obtain a heavy gasoline product; wherein the mixed catalyst comprises an adsorption desulfurization catalyst and an olefin aromatization catalyst.

According to the invention, in order to directly produce the gasoline of national V or even VI, the method can further comprise the following steps: and mixing the obtained etherified oil and the heavy gasoline product to obtain a gasoline product.

According to the present invention, the desulfurization and aromatization reaction refers to a process of desulfurizing heavy gasoline fraction and converting olefins into aromatics under the combined action of an adsorption desulfurization catalyst and an olefin aromatization catalyst in the presence of hydrogen, accompanied by a cracking reaction, and the conditions may include: the reaction temperature is 350-500 ℃, the preferable temperature is 380-420 ℃, and the weight hourly space velocity is 2-50 h^-1Preferably 5 to 20 hours^-1Reaction pressure of 0.5-3.0MPa, preferably 1.5-2.5MPa, hydrogen to heavy gasoline fraction volume ratio (at 0 deg.C (273K) in Standard conditions (STP), 1.01X 10⁵Pa) of 1 to 500, preferably 50 to 200.

According to the present invention, the adsorption desulfurization catalyst is well known to those skilled in the art, and may contain silica, alumina, zinc oxide, and a desulfurization active metal, which may be at least one selected from the group consisting of cobalt, nickel, copper, iron, manganese, molybdenum, tungsten, silver, tin, and vanadium.

In one embodiment, the adsorbed desulfurization catalyst comprises 10-90 wt.% zinc oxide, 5-85 wt.% silica, and 5-30 wt.% alumina, based on the dry weight of the adsorbed desulfurization catalyst and based on the weight of the oxides; the content of the desulfurization active metal in the adsorption desulfurization catalyst is 5-30 wt% based on the dry weight of the adsorption desulfurization catalyst and calculated by the weight of elements.

According to the invention, the adsorptive desulfurization catalyst may also contain 1 to 10 wt.% of coke-like substances. Industrial practice shows that the carbon content of the adsorption desulfurization catalyst has an influence on the desulfurization efficiency of the adsorption desulfurization catalyst and the octane number loss of gasoline, and the desulfurization efficiency of the adsorption desulfurization catalyst is gradually reduced along with the increase of the carbon content of the adsorption desulfurization catalyst, so that the octane number loss of the gasoline is reduced. Likewise, it is essential that the adsorptive desulfurization catalyst maintain a certain sulfur content. Practice shows that the sulfur carrying amount of the spent adsorption desulfurization catalyst is 9-10 wt%, the sulfur carrying amount of the regenerated adsorption desulfurization catalyst is 5-6 wt%, and the sulfur difference between the spent adsorption desulfurization catalyst and the regenerated adsorption desulfurization catalyst is about 4 wt%. In order to reduce the octane number loss of gasoline, the operation of small sulfur difference and large circulation amount which is generally considered reasonable can be adjusted to the operation of small circulation amount and large sulfur difference, the sulfur content of the regenerated adsorption desulfurization catalyst is reduced, the sulfur content of the spent adsorption desulfurization catalyst is improved, the octane number loss is reduced, the two operations are substantially the operations of keeping the higher sulfur carrying amount of the adsorption desulfurization catalyst participating in the reaction in a reactor, reducing the activity of the adsorption desulfurization catalyst and reducing the octane number loss.

According to the present invention, the olefin aromatization catalyst refers to a catalyst capable of converting hydrocarbons such as olefins in a gasoline feedstock into aromatic hydrocarbons, generally comprising a molecular sieve, preferably comprising a molecular sieve, a support and a metal, for example, the olefin aromatization catalyst may contain 10 to 30 wt% of the molecular sieve, 0 to 20 wt% of an aromatization active metal oxide and 50 to 90 wt% of the support on a dry basis and based on the total weight of the olefin aromatization catalyst; the molecular sieve may include a Y molecular sieve and/or an MFI structure molecular sieve, preferably a five-membered ring high-silicon molecular sieve, which may be in a hydrogen form, or modified with rare earth and/or phosphorus, and has a silicon-aluminum ratio of preferably greater than 100, more preferably greater than 150. The MFI structure molecular sieve may be at least one selected from the group consisting of ZSM-5, ZSM-8 and ZSM-11. The aromatization active metal may exert a partial desulfurization or hydrocarbon conversion function, and may be, for example, at least one selected from the group consisting of a group IVB metal element, a group VB metal element, a group VIB metal element, a group VIII metal element, a group IB metal element, a group IIB metal element, and a group IIIA metal element; wherein the metal element of the IVB group is preferably Zr or/and Ti, the metal element of the VB group is preferably V, the metal element of the VIB group is preferably Mo or/and W, the metal element of the VIII group is preferably one or more of Fe, Co and Ni, the metal element of the IB group is preferably Cu, the metal element of the IIB group is preferably Zn, the metal element of the IIIA group is preferably Ga, further, the aromatization active metal is preferably at least one selected from Fe, Zn and Ga, and the content is preferably 0.5-5 wt%. The support preferably comprises silica and/or alumina. The particle size of the olefin aromatization catalyst is generally 20-120 microns, which is equivalent to the particle size of the adsorption desulfurization catalyst. The invention mixes the adsorption desulfurization catalyst and the olefin aromatization catalyst after being respectively formed (such as spray drying).

One specific embodiment of the preparation process of the MFI structure molecular sieve may include ammonia exchange, phosphorus modification, metal component modification, and calcination treatment steps, and more specifically, sodium type molecular sieve with MFI structure obtained by conventional crystallization is prepared according to the following steps: ammonia salt: h₂O is 1: (0.1-1): (5-10) exchanging at room temperature to 100 ℃ for 0.3-1 hour, filtering, introducing a phosphorus-containing compound and a compound containing one or more of Fe, Co, Ni, Zn, Mn, Ga and Sn to modify the molecular sieve, and then roasting at 400-800 ℃ for 0.5-8 hours, wherein the roasting treatment process can also be carried out in a water vapor atmosphere. Furthermore, the MFI structure molecular sieve provided by the invention can be modified in the preparation process by adopting an impregnation or ion exchange mode. Further, the phosphorus-containing compound may be one selected from phosphoric acid, ammonium hydrogen phosphate, ammonium dihydrogen phosphate or ammonium phosphate, or a mixture thereof. Further, the Fe, Co, Ni, Zn, Mn, Ga and Sn compounds may be selected from their water-soluble salts, which may be one or more selected from sulfate, nitrate and chloride salts. Further, the MFI structure molecular sieve provided by the invention contains phosphorus and metal components, the acid center of the MFI structure molecular sieve is tightly combined with the dehydrogenation center of the metal, and meanwhile, the existence of the phosphorus can not only improve the structural stability of the molecular sieve, but also partially poison the dehydrogenation capacity of the metal.

The method for introducing the metal active component into the molecular sieve or the carrier can adopt various existing methods for loading metal oxides, such as an impregnation method, namely, one or more metal salt solutions are adopted for impregnating the molecular sieve or the carrier; or a precipitation method, namely one or more metal salt solutions or oxides and hydroxides thereof are adopted to deposit on the molecular sieve or the carrier; or the solid oxide and/or its precursor-metal salt or its hydroxide is mechanically mixed with the molecular sieve or carrier, with or without grinding; or sol processing, gelling, hydrothermal methods, and the like. The metal salt is mainly metal sulfate, nitrate, acetate, halide, metal ammonium salt, metal sodium salt and the like. The preferred method of introducing the metal active component of the present invention is a precipitation method or an impregnation method.

The ratio of the adsorption desulfurization catalyst and the olefin aromatization catalyst in the fluidized reactor may vary depending on the contents of olefins and sulfur in gasoline, for example, the ratio of the olefin aromatization catalyst to the mixed catalyst is 1 to 30% by weight, preferably 3 to 15% by weight.

According to the present invention, the gasoline raw material is well known to those skilled in the art and may be at least one selected from the group consisting of catalytically cracked gasoline, coker gasoline, thermally cracked gasoline, and straight run gasoline. The gasoline treated in accordance with the present invention is preferably a high olefin and high sulfur gasoline having an olefin volume fraction of generally greater than 20 volume percent, preferably greater than 30 volume percent, more preferably greater than 40 volume percent, and even more preferably greater than 50 volume percent; the sulfur content is generally 10. mu.g/g or more, preferably 50. mu.g/g or more, more preferably 100. mu.g/g or more, still more preferably 500. mu.g/g or more, and still more preferably 1000. mu.g/g or more, and the organic sulfides in gasoline are generally mercaptans, sulfides, thiophenes, alkylthiophenes, benzothiophenes, methylbenzothiophenes and the like.

According to the invention, the cut points of the light and heavy gasoline fractions may be between 60 and 80 ℃ and the cutting of the desulfurization and aromatization products is generally carried out in a fractionating column according to the distillation range from low to high, for example, the operating conditions of a gasoline cutting fractionating column are: the temperature at the top of the tower is 60-80 ℃, the temperature at the bottom of the tower is 120-160 ℃, and the operating pressure is 0.05-0.3 MPa.

According to the invention, the etherification treatment means the conversion of C in the light gasoline fraction₅The following lower hydrocarbons (e.g., isoamylene and cyclopentene) are etherified with alcohols to produce high octane etherified oils, for example, the step of etherification may include: contacting the light gasoline fraction with alcohols to ensure that olefins in the light gasoline fraction have etherification reaction with the alcohols under the action of an etherification catalyst to obtain the etherified oil; wherein the temperature of the etherification reaction can be 20-200 ℃, the pressure can be 0.1-5MPa, and the weight hourly space velocity can be 0.1-20 hours^-1The molar ratio of alcohols to light gasoline fraction may be 1: (0.1-100), the etherification catalyst may include at least one selected from the group consisting of resins, molecular sieves, and heteropolyacids, and the hydrocarbon may be at least one selected from the group consisting of methanol, ethanol, and propanol.

A specific implementation mode of etherification treatment is that a strong acid cation exchange resin catalyst is filled in a first-stage etherification and/or second-stage etherification fixed bed reactor, light gasoline fraction which is pretreated by desulfurization, diene removal and the like is introduced into the etherification reactor, the reaction temperature is 50-90 ℃, and the liquid hourly space velocity is 1.0-3.0h^-1The methanol and the light gasoline fraction have etherification reaction under the condition that the molar ratio is 1-2, the etherification product is sent into a rectifying tower for separation, the etherified oil is obtained at the bottom of the tower, and the unreacted light hydrocarbon and the methanol are recycled. The reaction temperature in the etherification process is more suitably 55-60 ℃ at the inlet, less than 90 ℃ at the outlet and the preferred space velocity is 1-2h^-1The molar ratio of methanol to light gasoline fraction active olefins (isoolefins, e.g. isoamylene) is preferably from 1.2 to 1.4. Wherein, the content of the first-stage etherified olefin is higher, and the first-stage etherified olefin is suitable for adopting a mixed phase bed reactor, and the content of the second-stage etherified olefin is lower, and the second-stage etherified olefin is suitable for adopting an adiabatic fixed bed reactor. In addition, the isomerization unit can also be applied to the light gasoline etherification process. The etherification of the light gasoline has the advantages of reducing the olefin content of the gasoline, improving the octane number, reducing the vapor pressure, improving the added value, enhancing the blending benefit and the like, and the etherified oil can be used as a gasoline octane number blending component and can also be mixed with heavy gasoline fractions to be used as a full-cut gasoline product.

Fluidized reactors according to the invention are well known to those skilled in the art and may be selected, for example, from fluidized beds, risers, downgoing line reactors, composite reactors comprising risers and fluidized beds, composite reactors comprising risers and downgoing lines, composite reactors comprising two or more risers, composite reactors comprising two or more fluidized beds, composite reactors comprising two or more downgoing lines, preferably riser reactors and/or fluidized bed reactors, each of which may be divided into two or more reaction zones. The fluidized bed reactor can be one or more selected from a fixed fluidized bed, a bulk fluidized bed, a bubbling bed, a turbulent bed, a fast bed, a conveying bed and a dense-phase fluidized bed; the riser reactor can be one or more selected from the group consisting of an equal-diameter riser, an equal-linear-speed riser and various variable-diameter risers. Preferably, the fluidization reactor is selected from dense phase fluidization reactors.

According to the invention, the light gasoline fraction is generally pretreated before etherification reaction to remove impurities such as sulfide and diene, so as to prolong the service life of the etherification catalyst. Therefore, the method of the present invention may further comprise: and (2) pretreating the light gasoline fraction and then performing etherification treatment, wherein the pretreatment can be at least one selected from alkali liquor extraction treatment, mercaptan conversion treatment and selective hydrogenation treatment. The alkali liquor extraction treatment uses alkali liquor to extract the mercaptan of the light gasoline fraction into the alkali liquor for removal; the mercaptan conversion treatment can be carried out by converting the small-molecular mercaptan into other sulfides, and the removal can be carried out by adopting a conventional alkali-free deodorization process, pre-hydrogenation and other modes, and the used catalyst and the catalyst promoter can be catalysts commonly used in the field. Selective hydrotreating is well known to those skilled in the art for the removal of diolefins from gasoline and can isomerize 3-methyl-1-butene to 2-methyl-1-butene.

A specific embodiment of the present invention will be provided with reference to the accompanying drawings, but the present invention is not limited thereto.

As shown in fig. 1, a high-olefin high-sulfur gasoline raw material 1 is firstly fed into a fractionating tower 2 for cutting and fractionating into a light gasoline fraction 10 and a heavy gasoline fraction 3, wherein the cutting points of the light gasoline fraction and the heavy gasoline fraction are about 65-70 ℃. The light gasoline fraction enters a pretreatment unit 11 to be pretreated by mercaptan removal and the like to obtain light gasoline 12 before etherification, the light gasoline 12 is mixed with methanol 13 and enters an etherification device 14 to react, and an etherification product 15 is fractionated by a fractionating tower 16 to obtain etherified oil 18 and methanol-containing tail gas 17. The heavy gasoline fraction 3 and hydrogen 4 are mixed and then enter a fluidized reactor 5, and are contacted with an adsorption desulfurization catalyst and an olefin aromatization catalyst to carry out adsorption desulfurization and aromatization reaction, and a desulfurization and aromatization product 6 enters a high-pressure separator 7 to obtain a heavy gasoline product 9 and tail gas 8. The heavy gasoline product 9 and the etherified oil 18 after the etherification treatment are mixed in a mixer 19 to obtain a high-octane clean gasoline product 20.

The following examples further illustrate the invention but are not intended to limit the invention thereto.

Examples I to II

The full range of gasoline stocks used in examples I and II were stabilized gasolines A and B, the properties of which are given in Table 1.

The stabilized gasolines A and B are separately distilled in a fractionating column and cut into light and heavy fractions, the light fraction end point being controlled to be between 65 and 70 ℃ (according to ASTM D86). Wherein, the light gasoline fraction obtained by distilling the stabilized gasoline A is marked as LCN-A, the heavy gasoline fraction is marked as HCN-A, the light gasoline fraction obtained by distilling the stabilized gasoline B is marked as LCN-B, the heavy gasoline fraction is marked as HCN-B, and the properties of the light gasoline fraction and the heavy gasoline fraction obtained by distilling the stabilized gasolines A and B are listed in Table 2. The light gasoline fraction is subjected to desulfurization and diene removal pretreatment in a refining reactor under the hydrogen condition, so that the sulfur content and the diene content in the light gasoline fraction are reduced to below 10ppm, and then the light gasoline fraction is mixed with methanol and enters an etherification reactor for etherification reaction, wherein the etherification reaction conditions are as follows: the reaction temperature is 55-80 ℃, and the space velocity is 1.2h^-1The mol ratio of active olefin (isoolefin) in the methanol and light gasoline fraction is 1.2, the etherification product obtained by the reaction is separated in an etherification fractionating tower, the gas phase at the top of the tower is methanol-containing tail gas containing residual carbon five and methanol, the etherification oil is obtained at the bottom of the tower, and the tower of the etherification fractionating tower is providedThe top temperature is 60-80 ℃, and the bottom temperature is 110-140 ℃. The corresponding etherified oils are designated LCN-A-M and LCN-B-M, and their properties are also set forth in Table 2.

The adsorption desulfurization catalysts used in the following examples and comparative examples were produced by catalyst division of petrochemical Co., Ltd., China, under the product number FCAS, and the aromatization catalyst used was a laboratory-made catalyst under the brand number OTAZ-C-3, and the properties of the adsorption desulfurization catalyst and the aromatization catalyst are shown in Table 3.

The preparation method of the aromatization catalyst OTAZ-C-3 comprises the following steps: 50g (NH)₄)₂SO₄Dissolving in 1000g water, adding 100g (dry basis) of crystallized product ZSM-5 molecular sieve (produced by Changling catalyst factory, without amine synthesis), exchanging at 95 deg.C for 1h, and filtering to obtain filter cake; 8.6g (NH)₄)₂HPO₄Dissolving in 60g of water, mixing with a filter cake, soaking and drying; 6.0gGa (NO) was added₃)₃·9H₂Dissolving O in 120g of water, mixing with the sample, soaking and drying; roasting the obtained sample at 580 ℃ for 3 hours to obtain a molecular sieve product; the obtained molecular sieve product is added into 500 g (dry basis) of silicon-aluminum colloid, and the microsphere catalyst is prepared by spray drying.

In each of the following examples and comparative examples, Na was contained in the catalyst₂O、NiO、ZnO、Ga₂O₃、Al₂O₃、SiO₂The content of (B) is determined by X-ray fluorescence, wherein Al is₂O₃、SiO₂The content of (A) is determined by referring to RIPP134-90, and the determination method of the rest components is similar.

The octane numbers RON and MON of the gasolines in the inventive and comparative examples were determined using standard methods of GB/T5487-1995 and GB/T503-1995, respectively, the antiknock index (MON + RON)/2, the gasoline PONA using simulated distillation and gasoline hydrocarbon analysis (tested using test methods ASTM D2887 and ASTM D6733-01(2011), respectively), and the gasoline sulfur content using SH/T0689-2000.

Example 1

The heavy gasoline fraction with the number of HCN-A is mixed with adsorption desulfurization catalysts FCAS and FCAS in A small continuous fluidized bed reactorThe mixed catalyst of the aromatization catalyst OTAZ-C-3 (the OTAZ-C-3 accounts for 7 percent of the total weight of the catalyst) is contacted to carry out adsorption desulfurization and aromatization reaction. The operating conditions were: the reaction temperature is 400 ℃, the pressure of the reactor is 2.1MPa, and the weight hourly space velocity of the heavy gasoline fraction is 6 hours^-1The volume ratio of hydrogen to the heavy gasoline fraction was 75. The desulfurization and aromatization products obtained from the top of the reactor were cooled and separated to obtain tail gas and heavy gasoline products (denoted as HCN-A heavy gasoline product, see table 4 for properties below). The regeneration temperature of the mixed catalyst is 550 ℃, and the regenerated mixed catalyst returns to the reactor for recycling.

Comparative example 1

Essentially the same procedure as in example 1, except that the adsorptive desulfurization reaction was carried out using all of the adsorptive desulfurization catalyst FCAS, the HCN-A heavy gasoline product properties are set forth in Table 4.

As can be seen from table 4, the desulfurization efficiency of example 1 is comparable to that of comparative example 1, while the antiknock index of example 1 loses 0.5 units less than that of comparative example 1.

Example 2

Essentially the same operation as in example 1, except that the heavy gasoline fraction numbered HCN-B was treated under the following operating conditions: the reaction temperature is 400 ℃, the pressure of the reactor is 1.8MPa, and the weight hourly space velocity of the heavy gasoline fraction is 8 hours^-1The volume ratio of hydrogen to the heavy gasoline fraction was 60. The HCN-B heavy gasoline product properties are listed in Table 5.

Comparative example 2

The operation was substantially the same as that of example 1 except that the adsorptive desulfurization reaction was carried out using the adsorptive desulfurization catalyst FCAS in its entirety and the HCN-B heavy gasoline product properties are shown in Table 5.

As can be seen from table 5, the desulfurization efficiency of example 2 is comparable to that of comparative example 2, while the antiknock index of example 2 loses 0.3 units less than that of comparative example 2.

Example 3

The heavy gasoline product obtained in example 1 was blended with an etherified oil, LCN-A-M, to give A high octane clean gasoline product, the properties of which are listed in table 6.

Comparative example 3

The heavy gasoline product obtained in comparative example 1 was blended with an etherified oil, LCN-A-M, to give A gasoline product having the properties listed in table 6.

It can be seen from table 6 that example 3 has a comparable sulfur content to comparative example 3, whereas the antiknock index of example 3 is increased by about 2.0 units over comparative example 3.

Example 4

The heavy gasoline product obtained in example 2 was blended with an etherified oil, LCN-B-M, to give a high octane clean gasoline product, the properties of which are listed in table 6.

Comparative example 4

The heavy gasoline product obtained in comparative example 2 was blended with etherified oil LCN-B-M to obtain a gasoline product having the properties listed in Table 6.

It can be seen from table 6 that example 4 has a comparable sulfur content to comparative example 4, while the antiknock index of example 4 is increased by about 1.0 unit over comparative example 4.

TABLE 1

TABLE 2

TABLE 3

Catalyst and process for preparing same	FCAS	OTAZ-C-3
			Chemical composition, weight%
Alumina oxide
		13	50.3
Sodium oxide				/	0.06
	Nickel oxide	21	/
Zinc oxide				52	/
	Gallium oxide	/	1.5
Silicon oxide				14	48.14
	Apparent density, kg/m³	1010	800
Pore volume, mL/g				/	0.27
	Specific surface area, m²/g	/	218
Abrasion index in% by weight^-1				/	1.5
	Sieving to obtain fine powder
0 to 40 μm				14.5	13.9
	40 to 80 μm	51.9	49.5
>80 micron				33.6	36.6
	Micro-inverse activity	/	80

TABLE 4

Experimental protocol	HCN-A	Examples1	Comparative example 1
				Gasoline type	HCN-A	HCN-A heavy gasoline product	HCN-A heavy gasoline product
Gasoline PONA, weight%
				nP	4.13	9.06	7.27
iP	22.45	28.06	28.04
				O	37.74	23.12	26.45
N	6.99	8.8	9.4
				A	28.27	30.76	28.62
Total up to	99.58	99.8	99.78
				Measured RON	87.2	86.1	85.6
Measured MON	77.3	76.6	76.2
				(RON+MON)/2	82.3	81.4	80.9
Loss of antiknock index	/	-0.9	-1.4
				Sulfur content, ppm	692	9	9

TABLE 5

Experimental protocol	HCN-B	Example 2	Comparative example 2
				Gasoline type	HCN-B	HCN-B heavy gasoline product	HCN-B heavy gasoline product
Gasoline PONA, weight%
				nP	3.14	7.1	4.1
iP	28.83	33.06	33.05
				O	24.12	13.38	16.65
N	12.28	12.13	13.65
				A	31.17	34.1	32.09
Total up to	99.54	99.77	99.54
				Measured RON	85.2	84.9	84.5
Measured MON	77.3	77.2	77.0
				(RON+MON)/2	81.3	81.1	80.8
Loss of antiknock index	/	-0.2	-0.5
				Sulfur content, ppm	246	6	6

TABLE 6

Claims

1. A method of treating gasoline, the method comprising:

cutting a gasoline raw material to obtain a light gasoline fraction and a heavy gasoline fraction;

carrying out etherification treatment on the obtained light gasoline fraction to obtain etherified oil;

feeding the obtained heavy gasoline fraction into a fluidized reactor to contact with a mixed catalyst and carrying out desulfurization and aromatization reactions under the hydrogen condition to obtain a heavy gasoline product; wherein the mixed catalyst comprises an adsorption desulfurization catalyst and an olefin aromatization catalyst; the adsorption desulfurization catalyst and the olefin aromatization catalyst are respectively molded and then are mixed for use;

on a dry basis and based on the total weight of the olefin aromatization catalyst, the olefin aromatization catalyst comprises 10 to 30 weight percent of a molecular sieve, 0.5 to 5 weight percent of an aromatization active metal and 50 to 90 weight percent of a support; wherein the molecular sieve comprises an MFI structure molecular sieve and the aromatization active metal is Ga; the olefin aromatization catalyst also contains phosphorus.

2. The method of claim 1, further comprising: and mixing the obtained etherified oil and the heavy gasoline product to obtain a gasoline product.

3. The process of claim 1 wherein the volume fraction of olefins in the gasoline feedstock is greater than 20% by volume.

4. The process of claim 1 wherein the gasoline feedstock has a sulfur content of 10 μ g/g or greater.

5. The process of claim 1, wherein the gasoline feedstock is at least one selected from the group consisting of catalytically cracked gasoline, coker gasoline, thermally cracked gasoline, and straight run gasoline.

6. The process according to claim 1, wherein the cut points of the light and heavy gasoline fractions are between 60 and 80 ℃.

7. The process of claim 1, wherein the step of etherification treatment comprises: contacting the light gasoline fraction with alcohols to ensure that olefins in the light gasoline fraction have etherification reaction with the alcohols under the action of an etherification catalyst to obtain the etherified oil; wherein the temperature of the etherification reaction is 20-200 ℃, the pressure is 0.1-5MPa, and the weight hourly space velocity is 0.1-20 hours^-1The molar ratio of the alcohols to the light gasoline fraction is 1: (0.1-100), wherein the etherification catalyst comprises at least one selected from the group consisting of resins, molecular sieves, and heteropolyacids.

8. The method of claim 1, wherein the fluidization reactor is a riser reactor and/or a dense phase fluidized bed reactor.

9. The method according to claim 1, wherein the adsorption desulfurization catalyst contains silica, alumina, zinc oxide, and a desulfurization active metal which is at least one selected from the group consisting of cobalt, nickel, copper, iron, manganese, molybdenum, tungsten, silver, tin, and vanadium.

10. The process of claim 9 wherein the adsorbed desulfurization catalyst comprises from 10 to 90 wt.% zinc oxide, from 5 to 85 wt.% silica, and from 5 to 30 wt.% alumina, based on the dry weight of the adsorbed desulfurization catalyst and based on the weight of oxides; the content of the desulfurization active metal in the adsorption desulfurization catalyst is 5-30 wt% based on the dry weight of the adsorption desulfurization catalyst and calculated by the weight of elements.

11. The method of claim 1, wherein the support comprises silica and/or alumina.

12. The process of claim 11 wherein the MFI structure molecular sieve is at least one selected from ZSM-5, ZSM-8 and ZSM-11.

13. The process according to claim 1, wherein the proportion of the olefin aromatization catalyst in the mixed catalyst is from 1 to 30 weight percent based on weight.

14. The process of claim 1 wherein the conditions of the desulfurization and aromatization reactions comprise: the reaction temperature is 350-500 ℃, and the weight hourly space velocity is 2-50 h^-1The reaction pressure is 0.5-3.0MPa, and the volume ratio of hydrogen to heavy gasoline fraction is 1-500.

15. The method of claim 1, wherein the method further comprises: and (2) pretreating the light gasoline fraction and then performing etherification treatment, wherein the pretreatment is at least one selected from alkali liquor extraction treatment, mercaptan conversion treatment and selective hydrogenation treatment.