CN108659884B

CN108659884B - Method for desulfurizing gasoline

Info

Publication number: CN108659884B
Application number: CN201710193497.7A
Authority: CN
Inventors: 白旭辉; 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: 2017-03-28
Filing date: 2017-03-28
Publication date: 2020-10-27
Anticipated expiration: 2037-03-28
Also published as: CN108659884A

Abstract

The invention relates to a method for desulfurizing gasoline, which comprises the following steps: performing first cutting on a gasoline raw material to obtain a first light gasoline fraction and a first heavy gasoline fraction; feeding the obtained first heavy gasoline fraction into a first set of fluidized reactor to contact with an adsorption desulfurization catalyst and perform a first desulfurization reaction in a hydrogen state to obtain a first desulfurization product; feeding the obtained first light gasoline fraction into a second set of fluidization reactor to contact with an adsorption desulfurization catalyst and perform a second desulfurization reaction to obtain a second desulfurization product; performing second cutting on the obtained first desulfurization product to obtain a second light gasoline fraction and a second heavy gasoline fraction; and carrying out etherification treatment on the obtained second desulfurization product and the second light gasoline fraction together to obtain the etherified oil. The method provided by the invention can reduce the sulfur and olefin content in the gasoline, and can simultaneously reduce the octane number loss of the gasoline and keep the high gasoline yield.

Description

Method for desulfurizing gasoline

Technical Field

The invention relates to a method for desulfurizing 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. The adsorption process for removing sulfur-containing compound from fuel oil is to use adsorption desulfurizing catalyst to make hydrogenation 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.

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.

Chinese patent CN1766057A discloses a process for producing low sulfur low olefin gasoline by separating full boiling range cracked naphtha into at least two fractions, selectively hydrogenating polyunsaturated compounds, then etherifying light gasoline fractions, hydrodesulfurizing heavy gasoline fractions or chemisorbing to remove sulfur, and finally combining the two fractions to obtain low sulfur low olefin gasoline. The invention will treat low sulfur low olefin gasoline, but the octane number of the gasoline product is expected to be reduced to some extent.

The gasoline adsorption desulfurization (S Zorb for short) process has less octane number loss of gasoline and lower energy consumption of the device when reducing the sulfur content of the catalytically cracked gasoline. Therefore, in many domestic oil refineries, the S Zorb technology is selected to treat the catalytic cracking gasoline, and a plurality of sets of S Zorb devices are built, so that a space for optimizing the catalytic cracking gasoline treatment process flow exists.

Disclosure of Invention

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

In order to achieve the above object, the present invention provides a method for desulfurizing gasoline, the method comprising: performing first cutting on a gasoline raw material to obtain a first light gasoline fraction and a first heavy gasoline fraction; feeding the obtained first heavy gasoline fraction into a first set of fluidized reactor to contact with an adsorption desulfurization catalyst and perform a first desulfurization reaction in a hydrogen state to obtain a first desulfurization product; feeding the obtained first light gasoline fraction into a second set of fluidization reactor to contact with an adsorption desulfurization catalyst and perform a second desulfurization reaction to obtain a second desulfurization product; performing second cutting on the obtained first desulfurization product to obtain a second light gasoline fraction and a second heavy gasoline fraction; carrying out etherification treatment on the obtained second desulfurization product and the second light gasoline fraction together to obtain etherified oil; wherein the conditions of the first desulfurization reaction include: the first reaction temperature is 380-470 ℃, and the first reaction pressure is 2.0-3.5 MPa; the conditions of the second desulfurization reaction include: the second reaction temperature is 360-450 ℃, and the second reaction pressure is 1.5-3.0 MPa.

Optionally, the second reaction temperature is 5-30 ℃ lower than the first reaction temperature; and/or the second reaction pressure is 0.1MPa to 1.0MPa lower than the first reaction pressure.

Optionally, the method further includes: and mixing the obtained second heavy gasoline fraction with etherified oil to obtain a gasoline product.

Optionally, the volume fraction of olefins in the gasoline feedstock is greater than 10% by volume.

Optionally, the sulfur content in the gasoline raw material is above 10 μ g/g.

Optionally, the gasoline raw material is at least one selected from catalytically cracked gasoline, coker gasoline, thermally cracked gasoline and straight run gasoline.

Optionally, the cut points of the first light gasoline fraction and the first heavy gasoline fraction are 60-100 ℃, and the cut points of the second light gasoline fraction and the second heavy gasoline fraction are 60-100 ℃.

Optionally, the first set of fluidization reactor and the second set of fluidization reactor are independently selected from at least one of a fluidized bed, a riser, a descending conveyor line reactor, a composite reactor composed of a riser and a fluidized bed, a composite reactor composed of a riser and a descending conveyor line, a composite reactor composed of two or more risers, a composite reactor composed of two or more fluidized beds, and a composite reactor composed of two or more descending conveyor lines, and preferably one or more of an equal-diameter fluidization riser, a variable-diameter riser, and a dense-phase fluidized bed reactor, and both the first set of fluidization reactor and the second set of fluidization reactor belong to a gasoline adsorption desulfurization device.

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

Optionally, on the basis of the dry weight of the adsorption desulfurization catalyst and by weight of oxides, the adsorption desulfurization catalyst contains 10-90 wt% of zinc oxide, 5-85 wt% of silica, and 5-30 wt% of alumina; 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.

Optionally, the step of etherification treatment comprises: contacting the second light gasoline fraction and the second desulfurization product with alcohols, and carrying out etherification reaction on olefins in the second light gasoline fraction and the second desulfurization product 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, the weight hourly space velocity is 0.1-20 h < -1 >, the ratio of the mole number of the alcohols to the sum of the mole numbers of the second light gasoline fraction and the second desulfurization product is 1: (0.1-100), wherein the etherification catalyst comprises at least one selected from the group consisting of resins, molecular sieves, and heteropolyacids.

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

1. the method of the invention divides the gasoline raw material into a first light gasoline fraction and a first heavy gasoline fraction, then the two gasoline fractions are respectively treated in two fluidization reactors, harsh or mild reaction conditions can be respectively adopted, and the octane number and the high yield of the gasoline can be kept while the sulfur content of the gasoline component is reduced.

2. According to the invention, the second light gasoline fraction and the second desulfurization product are subjected to etherification treatment, so that a light gasoline fraction pretreatment unit is omitted, olefins in the light gasoline fraction can be reduced, an etherification product with a high octane number can be produced, and the octane number of a gasoline product is improved.

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

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 raw material cutting tower 2 first set of fluidization reactor 3 first set of high-pressure separator

4 second set of fluidization reactors 5 second set of high pressure separator 6 distillation column

7 etherification reactor 8 etherification product fractionating tower 9 blender

Line 10 line 11 line 12 line

13 line 14 line 15 line

16 line 17 line 18 line

19 line 20 line 21 line

22 line 23 line 24 line

25 line 26 line

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 method for desulfurizing gasoline, which comprises the following steps: performing first cutting on a gasoline raw material to obtain a first light gasoline fraction and a first heavy gasoline fraction; feeding the obtained first heavy gasoline fraction into a first set of fluidized reactor to contact with an adsorption desulfurization catalyst and perform a first desulfurization reaction in a hydrogen state to obtain a first desulfurization product; feeding the obtained first light gasoline fraction into a second set of fluidization reactor to contact with an adsorption desulfurization catalyst and perform a second desulfurization reaction to obtain a second desulfurization product; performing second cutting on the obtained first desulfurization product to obtain a second light gasoline fraction and a second heavy gasoline fraction; carrying out etherification treatment on the obtained second desulfurization product and the second light gasoline fraction together to obtain etherified oil; wherein the conditions of the first desulfurization reaction include: the first reaction temperature is 380-470 ℃, and the first reaction pressure is 2.0-3.5 MPa; the conditions of the second desulfurization reaction include: the second reaction temperature is 360-450 ℃, and the second reaction pressure is 1.5-3.0 MPa.

According to the invention, the desulfurization reaction refers to a process of desulfurization of a gasoline raw material in a hydrogen state under the action of an adsorption desulfurization catalyst, and the conditions can comprise: the reaction temperature is 350-500 ℃, the reaction pressure is 0.5-3.5MPa, and the weight hourly space velocity is 2-50 h^-1Hydrogen to gasoline feedstock volume ratio (at standard conditions (STP)0 deg.C (273K), 1.01X 10⁵Pa) is 1-500.

The inventors of the present invention have surprisingly found that the desulfurization reaction of the first heavy gasoline fraction and the first light gasoline fraction in the gasoline raw material can improve the yield and octane number of the gasoline product; for example, the first reaction temperature of the first desulfurization reaction may be 380-; the second reaction temperature of the second desulfurization reaction may be 360-450 deg.C, preferably 380-430 deg.C, and the second reaction pressure may be 1.5-3.0MPa, preferably 2.0-2.7 MPa.

Further, the present inventors have also found that controlling the desulfurization reaction conditions of the first heavy gasoline fraction and the first light gasoline fraction can further improve the yield and octane number of the gasoline product, for example, the second reaction temperature is at least 5 ℃ lower, preferably at least 10 ℃ lower, more preferably at least 20 ℃ lower, further preferably at least 30 ℃ lower than the first reaction temperature, and further, the second reaction temperature is 5 to 30 ℃ lower than the first reaction temperature; and/or the second reaction pressure is at least 0.1MPa lower than the first reaction pressure, preferably at least 0.2MPa lower, more preferably at least 0.5MPa lower, even more preferably at least 1.0MPa lower.

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

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 10 volume percent, preferably greater than 20 volume percent, more preferably greater than 30 volume percent, even 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 present invention, the cutting mode of the gasoline fraction is not limited. For example, for the catalytic cracking gasoline, the gasoline cut can be cut by a gasoline cutting tower, and a two-stage condensation cooling process such as a catalytic cracking main fractionating tower arrangement can also be adopted. The cut points of the first light gasoline fraction and the first heavy gasoline fraction and the cut points of the second light gasoline fraction and the second heavy gasoline fraction may each independently be in the range of from 60 to 100 ℃, preferably in the range of from 60 to 80 ℃, further preferably in the range of from 65 to 80 ℃, and the dry point of the Engler distillation of the first light gasoline fraction and the second light gasoline fraction may each independently be in the range of from 60 to 100 ℃, further preferably in the range of from 60 to 80 ℃. The cutting of the gasoline feedstock and/or the first desulfurization product is generally carried out in a fractionation column according to a distillation range from low to high, for example, the operating conditions of the fractionation column for the gasoline feedstock 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.

Fluidized reactors according to the invention are well known to the person skilled in the art and may be, for example, at least one reactor selected from the group consisting of 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 and 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, more preferably a variable diameter riser reactor.

According to the present invention, the adsorption desulfurization catalyst is well known to those skilled in the art, and for example, the adsorption desulfurization catalyst 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 etherification treatment means the conversion of C in the light gasoline (comprising a second light gasoline fraction and a second desulfurization product)₅The 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 second light gasoline fraction and the second desulfurization product with alcohols, and carrying out etherification reaction on olefins in the second light gasoline fraction and the second desulfurization product 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^-1And the ratio of the moles of said alcohol to the sum of the moles of the second light gasoline fraction and the moles of said second desulfurization product is 1: (0.1-100), wherein the etherification catalyst comprises at least one selected from the group consisting of resins, molecular sieves, and heteropolyacids.

An etherification treatment method comprises loading strong acid cation exchange resin catalyst in a stage of etherification and/or etherificationIn a two-stage etherification fixed bed reactor, introducing a second light gasoline fraction subjected to pretreatment such as desulfurization and diene removal and the like and a second desulfurization product into an etherification reactor, wherein the reaction temperature is 50-90 ℃, and the liquid hourly space velocity is 1.0-3.0h^-1And the methanol and active olefin (isoolefine, such as isoamylene) in the second light gasoline fraction and the second desulfurization product are subjected to etherification reaction under the condition that the molar ratio of the methanol to the active olefin is 1-2, the etherification product is sent into a rectifying tower for separation, etherified oil is obtained at the bottom of the tower, and unreacted light hydrocarbon and 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^-1Preferably, the molar ratio of methanol to active olefins in the second light gasoline fraction and said second desulfurized product is 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.

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 gasoline raw material is fed into a gasoline raw material cutting tower 1 through a pipeline 10 for first cutting, a first light gasoline fraction obtained by cutting at the top of the tower is introduced into a first set of fluidization reactor 2 through a pipeline 11, is mixed with hydrogen introduced through a pipeline 12, is subjected to a first desulfurization reaction under the action of an adsorption desulfurization catalyst, and a generated reaction oil gas is introduced into a first set of high-pressure separator 3 through a pipeline 13, and is separated to obtain a first light gasoline product which is led out through a pipeline 14. Introducing a first heavy gasoline fraction obtained at the bottom of a gasoline raw material cutting tower 1 into a second set of fluidization reactor 4 through a pipeline 16, mixing the first heavy gasoline fraction with hydrogen introduced through a pipeline 17, carrying out a second desulfurization reaction under the action of an adsorption desulfurization catalyst, introducing generated reaction oil gas into a second set of high-pressure separator 5 through a pipeline 18 for separation, introducing a second desulfurization product obtained by separation into a distillation tower 6 through a pipeline 19 for second cutting, and respectively introducing a second light gasoline fraction and a second heavy gasoline fraction obtained by cutting through a pipeline 22 and a pipeline 21, wherein the cutting point of the second light gasoline fraction and the second heavy gasoline fraction is about 60-70 ℃. The second light gasoline fraction led out from the pipeline 22 and the first desulfurization product led out from the pipeline 14 are converged and mixed with methanol led in through the pipeline 23, the mixture enters the etherification reactor 7 for reaction, the etherification product is led into the etherification product fractionating tower 8 through the pipeline 24 and fractionated to obtain etherified oil and tail gas, the tail gas is led out through the pipeline 26, and the etherified oil is led out through the pipeline 25 and converged with the second heavy gasoline fraction and led into the mixer 9 to obtain a gasoline product.

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

The adsorptive 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 properties of the adsorptive desulfurization catalysts are shown in Table 3.

In the following examples and comparative examples, NiO, ZnO and Al were contained in the catalyst₂O₃、SiO₂The content of (B) is determined by X-ray fluorescence, wherein Al is₂O₃、SiO₂The content of (A) is determined by referring to RIPP 134-90, and the determination method of the rest components is similar.

The octane number of the gasoline in the examples and the comparative examples of the invention is measured by an RIPP 85-90 method, the gasoline PONA is measured by simulated distillation and gasoline monomer hydrocarbon analysis (by an RIPP81-90 test method), and the sulfur content of the gasoline is measured by a sulfur content measurement method (a light combustion method) of a petroleum product according to the national standard GB/T380-1977 of the people's republic of China.

The fluidized reactors used in the examples and comparative examples were small fixed fluidized bed devices.

Example 1

The gasoline fraction used in example 1 was refinery stabilized gasoline a, the properties of which are given in table 1. As shown in FIG. 1, stabilized gasoline A is distilled in a gasoline raw material cutting tower 1 and cut into a first light gasoline fraction and a first heavy gasoline fraction, and the first gasoline fraction is controlledThe light gasoline fraction has an end point of 65-70 deg.C (according to ASTM D86). Wherein, the first light gasoline fraction obtained by distilling the stable gasoline A is marked as LCN-A-1, the first heavy gasoline fraction is marked as HCN-A-1, and the properties are listed in Table 2; the first heavy gasoline fraction HCN-A-1 is sent into A first set of fluidization reactor 4 to contact with A desulfurization catalyst FCAS and carry out A first desulfurization reaction in A hydrogen state, the reaction conditions are listed in Table 4, and A reaction product obtained from the top of the reactor is cooled and separated to obtain tail gas and A first desulfurization product (marked as desulfurized gasoline of HCN-A-1, the properties of which are shown in Table 4). Feeding the desulfurized gasoline of HCN-A-1 into A distillation tower 6, controlling the temperature at the top of the distillation tower 6 to be about 65 ℃, obtaining A second light gasoline fraction LCN-A-2 at the top of the distillation tower, and obtaining A second heavy gasoline fraction HCN-A-2 at the bottom of the distillation tower, wherein the properties are also listed in Table 2; sending the obtained first light gasoline fraction LCN-A-1 into A first set of fluidized reactor 2 to contact with A desulfurization catalyst FCAS and carrying out A second desulfurization reaction in A hydrogen state, wherein the reaction conditions are also listed in Table 4, and cooling and separating A reaction product obtained from the top of the reactor to obtain A tail gas and A second desulfurization product (marked as gasoline after desulfurization of LCN-A-1, the properties of which are shown in Table 4); the second light gasoline fraction LCN-A-2 and the desulfurized gasoline of LCN-A-1 are merged and mixed with methanol, and the mixture enters an etherification reactor 7 for reaction under the conditions that the reaction temperature is 55-80 ℃ and the airspeed is 1.2h^-1And the mol ratio of methanol to the total active olefin (isoolefin) in the gasoline of the second light gasoline fraction LCN-A-2 and the desulfurized LCN-A-1 is 1.2, and the etherification product obtained by the reaction is fractionated by an etherification product fractionating tower 8 to obtain bottom etherification oil and tail gas containing methanol at the top of the tower, wherein the temperature at the top of the etherification fractionating tower is 60-80 ℃, the temperature at the bottom of the tower is 110-140 ℃, the etherification oil is marked as LCN-A-M-0, and the properties are listed in Table 2. The obtained second heavy gasoline fraction HCN-A-2 and LCN-A-M-0 were mixed to obtain A gasoline product as A refined gasoline, the properties of which are shown in Table 5.

Example 2

Example 2 was operated substantially the same as example 1 except that the temperature of the second desulfurization reaction was controlled to 410 c to obtain a gasoline product having the properties shown in table 5.

Example 3

Example 3 the same operation as in example 1 was followed except that the temperature of the second desulfurization reaction was controlled at 410 deg.C and the pressure at 1.9MPa to obtain a gasoline product having the properties shown in Table 5.

Example 4

Example 4 was conducted in substantially the same manner as in example 1 except that the temperature of the second desulfurization reaction was controlled to 415 deg.c and the pressure was controlled to 2.1MPa, to obtain a gasoline product having the properties shown in table 5.

Comparative example 1

Feeding the stable gasoline A into A second set of fluidization reactor 2 to contact with an adsorption desulfurization catalyst FCAS and perform desulfurization reaction in A hydrogen state, wherein the reaction conditions are shown in Table 4, the desulfurization product obtained from the top of the reactor is cooled and separated to obtain tail gas and A desulfurized gasoline product (marked as CN-A desulfurized gasoline, the properties of which are shown in Table 5), and the desulfurized gasoline product is used as A gasoline product without fractionation and etherification; the CN-A desulfurized gasoline was used as A gasoline product and the properties are listed in Table 5.

Comparative example 2

The operation was carried out in two steps, the first step being the same as that of comparative example 1, and the second step being the cutting of the CN-A desulfurized gasoline into A light gasoline fraction LCN-A-S and A heavy gasoline fraction HCN-A-S in A distillation column, wherein the final boiling point of the light gasoline fraction was controlled to 65 to 70 ℃ (according to ASTM D86). The light gasoline fraction LCN-A-S and methanol were mixed and fed into an etherification reactor for etherification reaction under the same conditions and operation as in example 1, and the corresponding etherified oil was designated as LCN-A-M-S, and its properties are also shown in Table 2.

The heavy gasoline fraction HCN-A-S obtained above was mixed with etherified oil LCN-A-M-S to obtain A gasoline product, properties of which are shown in Table 5.

As can be seen from table 5, examples 1-4 have comparable desulfurization efficiencies to comparative examples 1 and 2, but the research octane number of example 1 lost 3.3 units less than comparative example 1 and 0.8 units less than comparative example 2; the research octane number of example 2 lost 3.3 units less than comparative example 1 and 0.6 units less than comparative example 2; the research octane number of example 3 lost 3.1 units less than comparative example 1 and 0.8 units less than comparative example 2; the research octane number of example 4 lost 2.6 units less than comparative example 1 and 0.1 units less than comparative example 2.

TABLE 1

Gasoline feedstock	Stable gasoline A
		Density at 20 ℃ in kg/m³	737.3
Refractive index at 20 DEG C	1.4212
		Carbon content,% (w)	86.36
Hydrogen content,% (w)	13.64
		Sulfur content, mg/L	421
Nitrogen content, mg/L	139
		Induction period, min	667
Group composition (FIA method)
		Aromatic hydrocarbons,% (volume fraction)	15.4
Olefin,% (volume fraction)	54.9
		Saturated hydrocarbons,% (volume fraction)	29.7
Measured RON	90.9
		Measured MON	78.9
Distillation range under normal pressure, deg.C
		IBP	44
5％	59
		10％	63
30％	80
		50％	106
70％	139
		90％	175
FBP	204

TABLE 2

TABLE 3

Catalyst and process for preparing same	FCAS
		Chemical composition, weight%
Alumina oxide
		11
Nickel oxide			20
	Zinc oxide	49
Silicon oxide			20
	Apparent density, kg/m³	1130
Sieving to obtain fine powder
	0 to 40 μm	14.5
40 to 80 μm			51.9
	>80 micron	33.6

TABLE 4

TABLE 5

Claims

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

performing first cutting on a gasoline raw material to obtain a first light gasoline fraction and a first heavy gasoline fraction; the cutting points of the first light gasoline fraction and the first heavy gasoline fraction are 60-100 ℃;

feeding the obtained first heavy gasoline fraction into a first set of fluidized reactor to contact with an adsorption desulfurization catalyst and perform a first desulfurization reaction in a hydrogen state to obtain a first desulfurization product;

feeding the obtained first light gasoline fraction into a second set of fluidization reactor to contact with an adsorption desulfurization catalyst and perform a second desulfurization reaction to obtain a second desulfurization product;

performing second cutting on the obtained first desulfurization product to obtain a second light gasoline fraction and a second heavy gasoline fraction; the cutting points of the second light gasoline fraction and the second heavy gasoline fraction are 60-100 ℃;

carrying out etherification treatment on the obtained second desulfurization product and the second light gasoline fraction together to obtain etherified oil;

wherein the conditions of the first desulfurization reaction include: the first reaction temperature is 380-470 ℃, and the first reaction pressure is 2.0-3.5 MPa; the conditions of the second desulfurization reaction include: the second reaction temperature is 360-450 ℃, and the second reaction pressure is 1.5-3.0 Mpa; the second reaction temperature is 5-30 ℃ lower than the first reaction temperature; and the second reaction pressure is 0.1MPa-1.0MPa lower than the first reaction pressure.

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

3. The process of claim 1 wherein the volume fraction of olefins in the gasoline feedstock is greater than 10% 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 method of claim 1, wherein the first set of fluidized reactors and the second set of fluidized reactors are each independently selected from at least one of a fluidized bed, a riser, a downline conveyor reactor, a composite reactor comprised of a riser and a fluidized bed, a composite reactor comprised of a riser and a downline conveyor, a composite reactor comprised of two or more risers, a composite reactor comprised of two or more fluidized beds, and a composite reactor comprised of two or more downlines.

7. The method as claimed in claim 1 or 6, wherein the first set of fluidization reactors and the second set of fluidization reactors are respectively and independently selected from one or more of an equal-diameter riser, a variable-diameter riser and a dense-phase fluidized bed reactor, and both the first set of fluidization reactors and the second set of fluidization reactors belong to a gasoline adsorption desulfurization device.

8. 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.

9. The process of claim 8 wherein the adsorbed desulfurization catalyst comprises from 10 to 90 weight percent zinc oxide, from 5 to 85 weight percent silica, and from 5 to 30 weight percent 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.

10. The process of claim 1, wherein the step of etherification treatment comprises: contacting the second light gasoline fraction and the second desulfurization product with alcohols, and carrying out etherification reaction on olefins in the second light gasoline fraction and the second desulfurization product 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^-1And the ratio of the number of moles of said alcohol to the sum of the number of moles of said second light gasoline fraction and the number of moles of said second desulfurization product is 1: (0.1-100), wherein the etherification catalyst comprises at least one selected from the group consisting of resins, molecular sieves, and heteropolyacids.