CN109207189B

CN109207189B - Mercaptan etherification method for FCC gasoline

Info

Publication number: CN109207189B
Application number: CN201811193166.4A
Authority: CN
Inventors: 张素珍; 黄志祥; 张丽娥; 黄凤玉
Original assignee: Boxing Xingye Fine Chemical Industry Development Co Ltd
Current assignee: Boxing Xingye Fine Chemical Industry Development Co., Ltd
Priority date: 2018-10-14
Filing date: 2018-10-14
Publication date: 2020-12-15
Anticipated expiration: 2038-10-14
Also published as: CN109207189A

Abstract

The invention relates to an FCC gasoline mercaptan etherification method, which adopts a fixed bed reactor, feeds gasoline raw materials into the reactor, and leads mercaptan in the gasoline raw materials and dialkene to generate a thioetherification reaction under the action of a catalyst, wherein the catalyst comprises a composite carrier and metal active components of nickel, molybdenum and magnesium. Reaction conditions are as follows: the reaction pressure is 0.1MPa to 5MPa, the volume ratio of hydrogen to oil is 2: 1 to 30: 1, the reaction temperature is 60 ℃ to 200 ℃, and the airspeed is 0.5 to 8h^‑1. The catalyst has the characteristics of high mercaptan etherification activity and low octane number loss, and has strong adaptability to different raw materials.

Description

Mercaptan etherification method for FCC gasoline

Technical Field

The invention relates to a mercaptan etherification method for FCC gasoline.

Background

With the stricter environmental regulations, countries in the world put forward stricter requirements on the quality of petroleum processing products, and particularly, the restriction on the sulfur content of the petroleum processing products is stricter. The sulfides contained in the light petroleum products are mainly mercaptan (RSH), thioether (RSR) and the like, wherein the mercaptan has the greatest influence on the quality of the products, and not only has foul smell and strong corrosivity, but also influences the stability of the products.

In recent years, thioetherification processes have been widely used to remove mercaptans from refinery hydrocarbon fractions, i.e. by using reactions between components in the feedstock. Specifically, some hydrocarbon fractions contain mercaptan and high-reactivity olefin and diene (such as butene, isoprene, etc.), and the thioetherification reaction is to convert the mercaptan into high-boiling-point thioether through the reaction between the mercaptan and the active olefin, and then separate the formed high-boiling-point thioether compound from the hydrocarbon fractions through fractionation, thereby achieving the purpose of removing the mercaptan from the raw material. Numerous patents have been reported on the prior art for the thioetherification of hydrocarbons. For example, patent US 5851383 discloses a process for sweetening light olefins and selectively hydrogenating the C produced in a catalytic cracking unit₃-C₅Mixing the distillate with hydrogen, feeding the mixture into a fixed bed reactor, reacting diene in the distillate with mercaptan under the action of a thioetherification catalyst to generate thioether with high boiling point, and selectively hydrogenating and saturating redundant diene into monoene; the reaction product is introduced into a distillation tower for fractionation, light components for removing mercaptan flow out from the tower top, and thioether and heavy components are enriched and discharged from the tower bottom. In a particular embodiment, the catalyst employed in the fixed bed reactor is a Ni-based catalyst on alumina as a support, which can effect sulfurThe thioetherification of alcohols and the selective hydrogenation of dienes. The temperature of the thioetherification reaction was 125 ℃ and the pressure was 4100 kPa. The thioetherification reaction temperature disclosed in the patent is too high, so that partial mono-olefin hydrogenation saturation and isomerization are caused, the utilization rate of olefin is low, and most of the olefin does not participate in the thioetherification reaction.

Patent US 7638041 discloses a process for treating FCC naphtha comprising thioetherification sweetening of the light naphtha fraction, selective hydrogenation of the middle distillate. The whole catalytically cracked naphtha is mixed with hydrogen and fed to a distillation column and divided into Light Components (LCN), Middle Components (MCN) and Heavy Components (HCN). The rectifying section of the distillation column is filled with thioetherification catalyst, wherein diolefin in LCN reacts with mercaptan to form high-boiling-point thioether, and the high-boiling-point thioether enters the stripping section through distillation and is concentrated at the bottom of the column. The LCN after mercaptan removal is discharged from the top of the tower. MCN enters a side stripping tower from side stream fraction, the tower is filled with a selective hydrogenation catalyst, light fraction in the MCN enters a front-end distillation tower from the top of the side stripping tower, simultaneously, dienes in the MCN are selectively hydrogenated into monoenes, and products are discharged from the bottom of the tower or are mixed with HCN (hydrogen cyanide) including sulfur-containing compounds at the bottom of the distillation tower. Wherein, the catalyst used in the thioetherification reaction is a supported Ni-based catalyst. The catalyst used in the selective hydrogenation unit is a supported palladium catalyst. The patent is silent as to the process conditions and the working examples of thioetherification reactions which are available for reference.

Patent US20100059413 discloses a thioetherification process for removing mercaptans from a gas fraction. In a specific embodiment, the feed gas contains hydrocarbons such as olefins, diolefins, and acetylenes, as well as sulfur impurities such as ethanethiol. The raw material gas keeps gas phase and hydrogen to be mixed and enter a thioetherification reactor, under the action of a catalyst, mercaptan and active olefin react to generate high-boiling-point thioether, a reaction product is introduced into a fractionating tower to be separated, gas fraction without mercaptan is discharged from the top of the tower, and heavy component thioether is enriched and discharged from the bottom of the tower. The thioetherification catalyst adopted by the process is a catalyst containing palladium, silver and other active metals, the thioetherification reaction temperature is 176 DEG F, and the reaction pressure is 150 psig. However, the patent does not contain much information about the thioetherification catalyst.

The catalyst has more components and contents, the preparation process is complex, and the quality of the catalyst product produced in large scale is difficult to control.

In order to overcome the defects of the prior art, a brand new mercaptan etherification catalyst is found, and the characteristics of high mercaptan etherification activity, good stability and low octane number loss are one of the problems to be solved urgently by the technical personnel in the field.

Disclosure of Invention

The invention provides an FCC gasoline mercaptan etherification method, which removes mercaptan and diene, and has the advantages of less side reaction, high activity and low octane value loss. In particular to a thioether compound generated by the reaction of mercaptan and dialkene in catalytic cracking gasoline, coking gasoline and the like.

The invention provides an FCC gasoline mercaptan etherification method, which adopts a fixed bed reactor, gasoline raw materials are introduced into the reactor, mercaptan in the gasoline raw materials and dialkene are subjected to a thioetherification reaction under the action of a catalyst, the catalyst comprises a composite carrier and metal active components of nickel, molybdenum and magnesium, and the weight of the catalyst is taken as a reference, the content of nickel oxide is 2-18 wt%, the content of molybdenum oxide is 2-20 wt%, the content of magnesium oxide is 0.01-1.5 wt%, and the content of the composite carrier is 65-85 wt%; the composite carrier comprises a silicon oxide-aluminum oxide carrier and a ZSM-5 molecular sieve, wherein the content of the silicon oxide-aluminum oxide carrier in the composite carrier is 65-90 wt%, the content of the ZSM-5 molecular sieve is 10-35 wt%, the silicon oxide-aluminum oxide carrier comprises 0.1-12 wt% of silicon oxide, 0.1-10 wt% of nickel-doped lanthanum ferrite and 0.1-4.0 wt% of potassium oxide, the carrier mesopores account for 3-75% of the total pores, the macropores account for 1.5-60% of the total pores, and micropores, mesopores and macropores in the carrier are distributed unevenly; reaction conditions are as follows: the reaction pressure is 0.1MPa to 5MPa, the volume ratio of hydrogen to oil is 2: 1 to 30: 1, the reaction temperature is 60 ℃ to 200 ℃, and the airspeed is 0.5 to 8h^-1。

Preferably, the reaction pressure is 1MPa to 4MPa, the volume ratio of hydrogen to oil is 2: 1 to 18: 1, the reaction temperature is 70 ℃ to 160 ℃, and the volume space velocity is 2 to 6h^-1。

Preferably, the following components are contained, based on the total weight of the catalyst: the content of nickel oxide is 5-15 wt%, the content of molybdenum oxide is 5.5-16 wt%, the mesopores of the carrier account for 3-65% of the total pores, and the macropores account for 1.5-50% of the total pores.

In the method for preparing the catalyst of the present invention, the nickel and molybdenum compounds used may be any of those disclosed in the prior art as being suitable for preparing the catalyst, such as nickel nitrate, nickel sulfate, nickel acetate, ammonium molybdate, molybdenum oxide, etc.

The application of the mercaptan etherification catalyst in a fixed bed gasoline mercaptan etherification device requires vulcanization treatment, and the mercaptan etherification catalyst comprises the following steps: the vulcanizing agent is introduced at the temperature of 100-200 ℃, and the space velocity is 1-8 h^-1The pressure is 0.1MPa to 5MPa, the vulcanization temperature is 200 ℃ to 300 ℃, and the temperature is kept for 1h to 10 h. The vulcanizing agent is selected from carbon disulfide, dimethyl disulfide, ethanethiol, propanethiol and the like.

The preparation method of the silica-alumina carrier comprises the following steps: adding pseudo-boehmite and sesbania powder into a kneading machine, uniformly mixing, adding an inorganic acid solution and an organic polymer, uniformly kneading, then adding nickel-doped lanthanum ferrite, and uniformly mixing to obtain an alumina precursor for later use; adding a silicon source and pseudo-boehmite into acid liquor of an organic polymer, and uniformly mixing to obtain a silicon source-pseudo-boehmite-organic polymer mixture, wherein the content of the organic polymer in the unit content of an alumina precursor is more than 2 times higher than that of the organic polymer in the silicon source-pseudo-boehmite-organic polymer mixture (abbreviated as silicon-aluminum-organic matter mixture), then mixing the silicon source-pseudo-boehmite-organic polymer mixture with the alumina precursor, adding a potassium source, extruding, forming, drying and roasting to obtain the silica-alumina carrier. The silicon source is silica gel, sodium silicate or silica micropowder. The alumina in the silicon-aluminum-organic matter mixture accounts for 1-35 wt% of the alumina in the carrier.

In the preparation process of the silicon oxide-alumina carrier, the organic polymer is one or more of polyvinyl alcohol, polyacrylic acid, sodium polyacrylate, polyethylene glycol and polyacrylate.

Preferably, the nickel-doped lanthanum ferrite in the silica-alumina carrier is 0.1-12 wt%, more preferably 0.2-8 wt%, and the nickel in the nickel-doped lanthanum ferrite accounts for 0.1-8 wt% of the lanthanum ferrite.

The preparation method of the nickel-doped lanthanum ferrite comprises the following steps: dissolving citric acid in deionized water, stirring and dissolving, then adding lanthanum nitrate and ferric nitrate into the citric acid, stirring and dissolving, and adding sodium polyacrylate, polyacrylate or polyacrylic acid, wherein the adding amount of the sodium polyacrylate, the polyacrylate or the polyacrylic acid is 0.1-10 wt% of the nickel-doped lanthanum ferrite, and preferably 0.1-8.0 wt%. Adding nickel-containing compound, stirring, drying, roasting and grinding to obtain the finished product. The nickel-containing compound includes nickel nitrate, nickel acetate, and the like.

The preparation method of the composite carrier comprises the following steps: adding a silicon oxide-alumina carrier, a ZZSM-5 molecular sieve and sesbania powder into a kneading machine, adding a polyacrylic acid sodium nitrate solution, kneading, molding, drying and roasting to obtain the composite carrier.

The preparation method of the catalyst can adopt the methods of dipping, spraying and the like, the solution containing the active components of nickel, potassium and molybdenum is dipped and sprayed on the silicon oxide-carrier, and then the catalyst is dried and roasted to obtain the catalyst. The catalyst can be prepared, for example, by the following steps: preparing a solution containing an active component and an auxiliary component, dipping a silicon oxide-alumina carrier, drying for 3-9 hours at 110-160 ℃, and roasting for 4-9 hours at 400-650 ℃ to finally obtain a catalyst product.

Compared with lanthanum ferrite, the nickel-doped lanthanum ferrite is added into a silicon oxide-aluminum oxide carrier, so that the arsenic resistance and the sulfur resistance are effectively improved, the prepared mercaptan thioetherification catalyst takes the nickel-doped lanthanum ferrite silicon oxide-aluminum oxide and a ZSM-5 molecular sieve as carriers, so that the mercaptan thioetherification activity is effectively improved, and in the preparation process of the silicon oxide-aluminum oxide carrier, the content of organic polymers in unit content in an aluminum oxide precursor is more than 2 times higher than that of organic polymers in a silicon-aluminum-organic matter mixture, so that the pore structure of the carrier can be improved, micropores, mesopores and macropores of the carrier are unevenly distributed, the polymerization of active olefin is effectively inhibited, the colloid resistance of the catalyst is improved, the stability and the service life of the catalyst are improved, and the long-period operation of a device is facilitated; but also promotes the surface of the carrier to generate more active site loading centers and improves the reaction activity of the catalyst.

The mercaptan etherification catalyst is suitable for removing mercaptan and diene from liquefied petroleum gas, FCC gasoline, catalytic pyrolysis gasoline and/or coking gasoline by mercaptan thioetherification; the catalyst has good activity. The loss of octane value RON of the gasoline is about 0.3-0.4 point, the activity of the catalyst is high, and the loss of the octane value is low. The mercaptan etherification method has strong adaptability to oil products with different sulfur contents, mercaptan sulfur contents and olefin contents.

Detailed Description

The present invention is described in further detail below by way of examples, which should not be construed as limiting the invention thereto.

The main raw material sources for preparing the catalyst are as follows: the raw material reagents used in the invention are all commercial products.

Example 1

1. Preparation of nickel-doped lanthanum ferrite

Dissolving 2.51mol of lanthanum nitrate in 120mL of water under the condition of stirring, adding citric acid, and stirring for dissolving; then adding 4.79mol of ferric nitrate, then adding 190g of sodium polyacrylate, then adding the water solution containing 42g of nickel nitrate, continuously stirring for 30min, and obtaining the nickel-doped lanthanum ferrite through drying, roasting and grinding.

2. Preparation of silica-alumina Carrier

5g of sodium polyacrylate is dissolved in nitric acid, 38g of silica powder and 50g of pseudo-boehmite powder are added and uniformly stirred to obtain a silica powder-pseudo-boehmite-sodium polyacrylate mixture (abbreviated as a silica-alumina-organic matter mixture), 1/8 is taken for later use, and 4.5g of nickel-doped lanthanum ferrite is added with citric acid for later use. Adding 300g of pseudo-boehmite powder and 25.0g of sesbania powder into a kneader, adding nitric acid, adding 40.2g of sodium polyacrylate nitric acid solution, uniformly mixing, adding the silicon micropowder-sodium polyacrylate mixture, uniformly kneading, adding nickel-doped lanthanum ferrite and 2.5g of potassium nitrate, uniformly mixing, and kneading and extruding to form a clover shape. Drying at 120 ℃ for 8 hours, and roasting at 650 ℃ for 6 hours to obtain the nickel-doped lanthanum ferrite-containing silica-alumina carrier 1. The mesopores of the carrier account for 55.4 percent of the total pores, and the macropores account for 28.6 percent of the total pores.

3. Preparation of composite Carrier

Adding the silicon oxide-alumina carrier, the ZZSM-5 molecular sieve and sesbania powder into a kneading machine, adding a sodium polyacrylate solution, kneading, molding, drying and roasting to obtain the composite carrier.

4. Preparation of the catalyst

Preparing a nickel, magnesium and molybdenum-containing solution to impregnate the carrier 1, drying at 140 ℃ for 6 hours, and roasting at 560 ℃ for 5 hours to obtain the catalyst 1. The composition of the catalyst is shown in table 1.

Example 2

The nickel-doped lanthanum ferrite is prepared as in example 1, except that 260g of sodium polyacrylate is added, and the silica-alumina carrier is prepared as in example 1, wherein the silica-alumina carrier comprises 4.4 wt% of silica, 5.7 wt% of nickel-doped lanthanum ferrite and 1.6 wt% of potassium, mesoporous pores of the carrier account for 64.2% of total pores, and macroporous pores account for 25.6% of total pores. The unit content of sodium polyacrylate in the alumina precursor is 3 times higher than that of sodium polyacrylate in the silicon source-organic polymer mixture. The preparation of the composite carrier was the same as in example 1, and the preparation of catalyst 2 was the same as in example 1.

Example 3

The nickel-doped lanthanum ferrite is prepared as in example 1, except that 220g of polyacrylic acid is added, and the silica-alumina carrier is prepared as in example 1, wherein the silica-alumina carrier comprises 8.4 wt% of silica, 2.6 wt% of nickel-doped lanthanum ferrite and 0.8 wt% of potassium, mesoporous pores of the carrier account for 54.6% of total pores, and macroporous pores account for 33.5% of total pores. The unit content of polyacrylic acid in the alumina precursor is 3.3 times higher than that of polyacrylic acid in the silicon source-organic polymer mixture. The preparation of the composite carrier was the same as in example 1, and the preparation of catalyst 3 was the same as in example 1.

Example 4

Nickel-doped lanthanum ferrite was prepared as in example 1 except that 280g of sodium polyacrylate was added, and a silica-alumina carrier was prepared as in example 1, the silica-alumina carrier contained 8.4 wt% of silica, 2.6 wt% of nickel-doped lanthanum ferrite, and 3.5 wt% of potassium, with the carrier mesopores accounting for 49.3% of the total pores and the macropores accounting for 39.4% of the total pores. The polyacrylate content per unit content in the alumina precursor was 3.3 times higher than the polyacrylate content in the silicon source-organic polymer mixture. The preparation of the composite carrier is the same as in example 1, and the preparation method of the catalyst is the same as in example 1.

Comparative example 1

1. Preparation of lanthanum ferrite

Dissolving 2.51mol of lanthanum nitrate in 120mL of water under the condition of stirring, adding citric acid, and stirring for dissolving; then adding 4.79mol of ferric nitrate, then adding 190g of sodium polyacrylate, stirring for 30min, drying, roasting and grinding to obtain the nickel-doped lanthanum ferrite.

2. Preparation of silica-alumina Carrier

5g of sodium polyacrylate is dissolved in nitric acid, 38g of silica powder and 50g of pseudo-boehmite powder are added and uniformly stirred to obtain a silica powder-pseudo-boehmite-sodium polyacrylate mixture (abbreviated as a silica-alumina-organic matter mixture), 1/8 is taken for later use, and 4.5g of lanthanum ferrite is added with citric acid for later use. Adding 300g of pseudo-boehmite powder and 25.0g of sesbania powder into a kneader, adding nitric acid, adding 40.2g of sodium polyacrylate nitric acid solution, uniformly mixing, adding the silicon micropowder-sodium polyacrylate mixture, uniformly kneading, adding lanthanum ferrite and 2.5g of potassium nitrate, uniformly mixing, and kneading and extruding to form the clover shape. Drying at 120 deg.C for 8 hr, and calcining at 650 deg.C for 6 hr to obtain the carrier 1-1 of silicon oxide-aluminium oxide containing lanthanum ferrite.

3. The composite carrier was prepared as in example 1.

4. Preparation of comparative catalyst 1

Preparing a nickel, magnesium and molybdenum-containing solution impregnated carrier 1-1, drying at 140 ℃ for 6 hours, and roasting at 560 ℃ for 5 hours to obtain a comparative catalyst 1.

Comparative example 2

1. Preparation of nickel-doped lanthanum ferrite

2. Preparation of silica-alumina Carrier

Adding citric acid into 4.5g of nickel-doped lanthanum ferrite for later use, adding 350g of pseudo-boehmite powder and 25.0g of sesbania powder into a kneader, adding nitric acid, adding 40.7g of sodium polyacrylate nitric acid solution, uniformly mixing, adding 4.8g of silicon micropowder, uniformly kneading, adding nickel-doped lanthanum ferrite and 2.5g of potassium nitrate, uniformly mixing, and kneading and extruding to form the clover shape. Drying at 120 deg.C for 8 hr, and calcining at 650 deg.C for 6 hr to obtain the carrier 1-2 containing nickel-doped lanthanum ferrite silica-alumina.

3. The composite carrier was prepared as in example 1.

4. Preparation of comparative catalyst 2

Preparing a nickel, magnesium and molybdenum-containing solution impregnated carrier 1-2, drying at 140 ℃ for 6 hours, and roasting at 560 ℃ for 5 hours to obtain a comparative catalyst 2.

Catalysts 1 to 4 and comparative catalysts were each charged in a fixed bed reactor to evaluate the catalyst reaction performance. The catalyst is presulfurized by using vulcanized oil, the vulcanization pressure is 3.2MPa, and the volume space velocity of the vulcanized oil is 3.5h^-1The vulcanization procedure is vulcanization treatment at 240 ℃ and 280 ℃ for 6h respectively. After the vulcanization treatment is finished, switching to full-fraction FCC gasoline for replacement treatment for 6h, then adjusting to reaction process conditions, and carrying out etherification sweetening and diene reaction. The FCC raw material gasoline contains 752 mug/g of sulfur, 32.4 mug/g of mercaptan sulfur, 22ppb of arsenic, 31.7 v% of olefin and 89.5 RON. The reaction process conditions are as follows: the reactor temperature is 90 ℃, and the volume space velocity is 3.5h^-1The volume ratio of hydrogen to oil is 16:1, and the reaction pressure is 2.8 MPa. After about 60 hours of reaction, a sample was taken for analysis, and the reaction results are shown in Table 2.

Table 1 example/comparative catalyst composition/wt%

TABLE 2 results of example/comparative example reaction for 60h

Examples/comparative examples	Mercaptan sulfur content/. mu.g/g	The olefin content v%	Loss of octane number	Gasoline yield wt%;
					example 1	0.2	31.4	0.2	98.8
Example 2	0.1	31.3	0.2	98.6
					Example 3	0.3	31.4	0.3	98.5
Example 4	0.4	31.5	0.3	98.7
					Comparative example 1	12	24.3	3.4	88.9
Comparative example 2	9	29.3	2.4	91.6

TABLE 3 results of the example reaction 600h

Examples	Mercaptan sulfur content/. mu.g/g	The olefin content v%	Loss of octane number	Gasoline yield wt%;
					example 1	0.2	31.2	0.2	98.6
Example 2	0.2	31.3	0.2	98.7

The reaction result shows that the olefin content is basically unchanged, the loss of the reaction octane number is 0.3-0.4, the etherification activity of the catalyst is high, the arsenic resistance and the sulfur resistance are good, and the loss of the octane number is low. The catalyst of the comparative example has low activity, and the catalyst can be gelatinized and even coked to reduce the activity.

The catalyst is subjected to a stability test, the reaction result after 600h of reaction operation is shown in table 3, the olefin content is basically unchanged, the catalyst is not easy to gel, even coke and deactivate, and the stability is good.

The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and it is therefore intended that all such changes and modifications as fall within the true spirit and scope of the invention be considered as within the following claims.

Claims

1. A method for etherifying mercaptan in FCC gasoline is characterized in that a fixed bed reactor is adopted, gasoline raw materials are introduced into the reactor, mercaptan in the gasoline raw materials and dialkene are subjected to a thioetherification reaction under the action of a catalyst, the catalyst comprises a composite carrier and metal active components of nickel, molybdenum and magnesium, the weight of the catalyst is taken as a reference, the content of nickel oxide is 2-18 wt%, the content of molybdenum oxide is 2-20 wt%, the content of magnesium oxide is 0.01-1.5 wt%, and the content of the composite carrier is 65-85 wt%; the composite carrier comprises a silicon oxide-aluminum oxide carrier and a ZSM-5 molecular sieve, wherein the content of the silicon oxide-aluminum oxide carrier in the composite carrier is 65-90 wt%, the content of the ZSM-5 molecular sieve is 10-24 wt%, the silicon oxide-aluminum oxide carrier comprises 0.1-12 wt% of silicon oxide, 0.1-10 wt% of nickel-doped lanthanum ferrite and 0.1-4.0 wt% of potassium oxide, the carrier mesopores account for 3-75% of the total pores, the macropores account for 1.5-60% of the total pores, and micropores, mesopores and macropores in the carrier are distributed unevenly; reaction conditions are as follows: the reaction pressure is 0.1MPa to 5MPa, the volume ratio of hydrogen to oil is 2: 1 to 30: 1, the reaction temperature is 60 ℃ to 200 ℃, and the airspeed is 0.5 to 8h^-1(ii) a The preparation method of the silica-alumina carrier comprises the following steps: adding pseudo-boehmite and sesbania powder into a kneading machine, uniformly mixing, adding an inorganic acid solution and an organic polymer, uniformly kneading, then adding nickel-doped lanthanum ferrite, and uniformly mixing to obtain an alumina precursor for later use; adding a silicon source and pseudo-boehmite into acid liquor of an organic polymer, and uniformly mixing to obtain a silicon source-pseudo-boehmite-organic polymer mixture, wherein the content of the organic polymer in the unit content of an alumina precursor is more than 2 times higher than that of the organic polymer in the silicon source-pseudo-boehmite-organic polymer mixture, then mixing the silicon source-pseudo-boehmite-organic polymer mixture with the alumina precursor, adding a potassium source, extruding, forming, drying and roasting to obtain the silica-alumina carrier.

2. The FCC gasoline mercaptan etherification method according to claim 1, wherein the reaction pressure is 1MPa to 4MPa, the hydrogen-oil volume ratio is 2: 1 to 18: 1, the reaction temperature is 70 ℃ to 160 ℃, and the volume space velocity is 2 to 6h^-1。

3. The FCC gasoline mercaptan etherification method of claim 1, wherein the carrier mesopores account for 3-65% of the total pores, and macropores account for 1.5-50% of the total pores; the catalyst comprises the following components by taking the total weight as a reference: the content of nickel oxide is 5-15 wt%, and the content of molybdenum oxide is 5.5-16 wt%.

4. The FCC gasoline mercaptan etherification method according to claim 1, wherein the silicon source is silica gel, sodium silicate or silica micropowder, and the alumina in the silicon source-pseudo-boehmite-organic polymer mixture accounts for 1-35 wt% of the alumina in the carrier.

5. The FCC gasoline mercaptan etherification method according to claim 1, wherein the organic polymer is one or more of polyvinyl alcohol, polyacrylic acid, sodium polyacrylate, polyethylene glycol, and polyacrylate.

6. The FCC gasoline mercaptan etherification method according to any one of claims 1 to 5, wherein the preparation method of the nickel-doped lanthanum ferrite comprises the following steps: dissolving citric acid in deionized water, stirring and dissolving, then adding lanthanum nitrate and ferric nitrate into the citric acid, stirring and dissolving, adding sodium polyacrylate, polyacrylate or polyacrylic acid, wherein the adding amount of the sodium polyacrylate, the polyacrylate or the polyacrylic acid is 0.1-10 wt% of that of the nickel-doped lanthanum ferrite, then adding a nickel-containing compound, stirring, drying, roasting and grinding to obtain a finished product.

7. The FCC gasoline mercaptan etherification method according to any one of claims 1 to 5, wherein the catalyst preparation method comprises the steps of: dipping the dipping solution containing the active component, spraying the dipping solution on a carrier, and then drying and roasting the catalyst to obtain the catalyst.

8. The FCC gasoline mercaptan etherification process of claim 7, wherein the catalyst is prepared as follows: preparing a silicon oxide-alumina carrier impregnated with a solution containing nickel, magnesium and molybdenum, drying the silicon oxide-alumina carrier at 110-160 ℃ for 3-9 hours, and roasting the silicon oxide-alumina carrier at 400-650 ℃ for 4-9 hours to finally obtain a catalyst product.