CN109261160B

CN109261160B - FCC gasoline selective hydrogenation catalyst and preparation method thereof

Info

Publication number: CN109261160B
Application number: CN201811193165.XA
Authority: CN
Inventors: 黄凤玉; 黄志祥; 张丽娥; 张素珍
Original assignee: Individual
Current assignee: Lin Yajuan
Priority date: 2018-10-14
Filing date: 2018-10-14
Publication date: 2020-12-11
Anticipated expiration: 2038-10-14
Also published as: CN109261160A

Abstract

The invention relates to a selective hydrogenation catalyst for FCC gasoline, which comprises a silicon oxide-aluminum oxide carrier and metal active components of nickel, molybdenum, zinc and lithium loaded on the carrier, wherein the content of nickel oxide is 2-15 wt%, the content of molybdenum oxide is 2-18 wt%, the content of zinc oxide is 0.1-5 wt%, and the content of lithium oxide is 0.1-2.5 wt%; the content of the silica-alumina carrier is 65-85 wt%. The catalyst has the characteristics of high mercaptan removal activity, high diolefin hydrogenation selectivity and low octane number loss.

Description

FCC gasoline selective hydrogenation catalyst and preparation method thereof

Technical Field

The invention relates to a catalyst for removing mercaptan from FCC gasoline by hydrogenation and a preparation method thereof.

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.

US6692635B2 discloses a process for producing gasoline with low sulphur content, in which a new mercaptan removal technology is used. The technology comprises the steps of introducing a full-fraction gasoline raw material into a selective hydrogenation reactor, enabling mercaptan and olefin or diene in gasoline to generate etherification reaction to generate high-boiling-point sulfur-containing compounds, and then fractionating selective hydrogenation products in a fractionating tower to obtain light gasoline fractions which do not contain mercaptan and have low total sulfur content and heavy gasoline fractions which have high sulfur content. The technology is characterized in that the addition reaction of mercaptan and dialkene is used for realizing the effective removal of mercaptan from light gasoline fraction and the transfer of mercaptan to heavy gasoline fraction, simultaneously realizing the removal of mercaptan and the reduction of the total sulfur content of light gasoline, and overcoming the problems that the traditional Merox process can not deeply desulfurize and has caustic sludge discharge.

CN1229838A discloses a hydrocarbon oil conversion method, which is to remove mercaptan from raw oil and a hydrofining catalyst under the process condition of hydrogenation mercaptan removal, wherein the hydrofining catalyst contains tungsten (molybdenum) oxide, nickel oxide and cobalt oxide loaded on an alumina carrier, the content of the tungsten (molybdenum) oxide is 4-10 wt%, the content of the nickel oxide is 1-5 wt%, the content of the cobalt oxide is 0.01-0.1 wt%, and the ratio of the total atomic number of nickel and cobalt to the total atomic number of nickel, cobalt and tungsten (molybdenum) is0.3 to 0.9. CN102451694A discloses a hydrogenation sweetening catalyst, a preparation method and application thereof. The catalyst takes alumina or silicon-containing alumina as a carrier, phosphorus as an auxiliary component, copper and zinc as active components, and the mass of the catalyst is taken as a reference, wherein the auxiliary phosphorus content is 0.5-3.0 wt%, the zinc oxide content is 3-15 wt%, and the copper oxide content is 5-30 wt%. Because the catalyst has strong hydrogenation activity, when the catalyst is used for treating full-range FCC gasoline, the mercaptan content is reduced from 38 mu g/g to 3 mu g/g, the olefin content is also reduced from 25 v% to 20 v%, and the RON loss is as high as 1.3 units. CN00136870.2 provides a selective mercaptan removal catalyst for removing mercaptan sulfur in aviation fuel and a preparation method thereof. The catalyst comprises the following components, by weight, 7-20 parts of molybdenum oxide; 0.1 to 5 portions of cobalt oxide; 0-5 parts of nickel oxide and 0-10 parts of silicon dioxide; phosphorus or boron or fluorine 0-4; 0 to 40 percent of alumina; 60-100 parts of titanium dioxide. The preparation method of the catalyst comprises the steps of soaking the catalyst carrier in the soaking solution for 1-2 hours, and then drying at 100-130 ℃; finally, roasting at 400-550 ℃ for 2-6 hours to obtain the catalyst. The catalyst has good removal effect and better low-temperature activity on mercaptan sulfur in jet fuel. CN201210393263.4 relates to a preparation method and application of a novel gasoline sweetening adsorbent. The preparation method of the gasoline sweetening adsorbent comprises the following steps: uniformly mixing a solvent, a metal ion precursor and a mesoporous material, aging, adding an organic ligand, and performing hydrothermal crystallization treatment; then, carrying out suction filtration, washing and drying on the product of the hydrothermal crystallization treatment to obtain a zeolite imidazole framework material/mesoporous material compound; and (3) carrying out tabletting molding, crushing and screening on the zeolite imidazole framework material/mesoporous material compound to obtain the gasoline sweetening adsorbent. In the zeolite imidazole framework material/mesoporous material composite provided by the invention, the specific surface area of the zeolite imidazole framework material is high, and the zeolite imidazole framework material is in a high-dispersion state on the mesoporous material, so that the diffusion limitation caused by agglomeration is effectively solved. The solvent is one or a combination of more of deionized water, methanol, ethanol and N, N-dimethylformamide; the metal ion is Zn²⁺、Cu²⁺And Co²⁺One or more ofA combination of several. CN200910082945.1 relates to a selective hydrogenation catalyst for catalytically cracked gasoline and a preparation method thereof. The catalyst of the invention consists of Al₂O₃-TiO₂The composite oxide carrier and the active metal oxide, wherein the NiO content in the active metal oxide is 10-20 w%, and the MoO content is calculated according to the weight percentage of the catalyst₃The content is 5-12 w%; wherein the carrier Al₂O₃-TiO₂Oxide TiO₂∶Al₂O₃The weight ratio of (A) to (B) is 0.01-1: 1. The catalyst of the invention can be used for treating catalytically cracked gasoline at low temperature (100-200 ℃), low pressure (1-3.0 MPa) and low hydrogen-oil ratio (5: 1-100: 1 of hydrogen-oil volume ratio), and shows high activity, selectivity and stability for removing diolefin and mercaptan. CN200910187903.4 discloses a hydrogenation sweetening catalyst, a preparation method and application thereof. The catalyst takes HZSM-5 molecular sieve as a main carrier component and copper and zinc as active components. The active components are 5-27% of copper oxide and 3-15% of zinc oxide by weight of oxides, and are prepared by adopting a saturated co-leaching technology. The catalyst of the invention is suitable for selective hydrogenation sweetening reaction of light oil products, has the characteristics of high sweetening activity, low olefin hydrogenation activity and the like, and has high liquid yield and little octane number loss after reaction. CN201610187374.8 provides a light hydrocarbon sweetening catalyst regulated and controlled based on an alumina crystal face and a preparation method thereof, wherein the catalyst takes gamma-alumina regulated and controlled by the hydrothermal treatment of the invention as a carrier and takes nickel and molybdenum as active metals. The light hydrocarbon sweetening catalyst is a high-activity and high-selectivity catalyst, can be used for catalyzing mercaptan in light hydrocarbons to react with diene to generate macromolecular sulfides, and can also be used for catalyzing selective hydrogenation saturation of diene. The invention relates to a catalyst for removing mercaptan sulfur in catalytically cracked gasoline at low temperature and a preparation method thereof, belonging to the field of gasoline desulfurization. A catalyst for removing mercaptan sulfur in catalytically cracked gasoline at low temperature, which comprisesThe alumina or the composite solid acid of the nano HZSM-5 molecular sieve and the alumina is taken as a carrier and comprises the following components in percentage by mass based on the total mass of the catalyst: 5 to 20 percent of zinc oxide, 5 to 15 percent of ferric oxide, 0.5 to 5 percent of lanthanum oxide and 0.5 to 5 percent of phosphorus oxide. The catalyst of the invention is suitable for low-temperature hydrogenation sweetening reaction of catalytic gasoline, and has the characteristics of high sweetening activity, low olefin hydrogenation saturation activity, high liquid yield, basically no loss of octane number and the like.

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.

The prior art mainly changes the chemical composition and type of a carrier and adds a promoter to improve the performance of a catalyst. In order to overcome the defects of the prior art, a brand new hydrogenation sweetening catalyst is found, which has the characteristics of high sweetening activity, high diolefin hydrogenation selectivity, good stability and low octane number loss, and is one of the problems to be solved by the technical personnel in the field.

Disclosure of Invention

The invention provides an FCC gasoline selective hydrogenation catalyst and a preparation method thereof, which can remove mercaptan and diene, and has the advantages of less side reaction, high activity and low octane number loss.

The invention provides an FCC gasoline selective hydrogenation catalyst, which comprises a silicon oxide-aluminum oxide carrier and metal active components of nickel, molybdenum, zinc and lithium loaded on the carrier, wherein the content of nickel oxide is 2-15 wt%, the content of molybdenum oxide is 2-18 wt%, the content of zinc oxide is 0.1-5 wt%, and the content of lithium oxide is 0.1-2.5 wt% based on the weight of the catalyst; the content of the silicon oxide-aluminum oxide carrier is 65-85 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 0.1-2.5 wt% of potassium, mesoporous pores of the carrier account for 3-75% of total pores, and macroporous pores account for 1.5-60% of the total pores. The micropores, mesopores and macropores in the carrier are not uniformly distributed.

Preferably, the following components are contained, based on the total weight of the catalyst: the content of nickel oxide is 4-15 wt%, and the content of molybdenum oxide is 5-16 wt%. The carrier mesopores 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 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 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, 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 nickel-molybdenum-zinc catalyst is capable of effectively improving the hydrogenation selectivity and the mercaptan removal activity of diene, and in the preparation process of the silicon oxide-aluminum oxide carrier, the content of organic polymers in unit content in the 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, the micropores, mesopores and macropores of the carrier are unevenly distributed, the polymerization of active olefin and the saturation of monoolefine (namely, olefin in the raw material is not hydrogenated), 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 the device is facilitated; and the surface of the carrier is promoted to generate more active site loading centers, and the hydrogenation and mercaptan removal activity of the catalyst is improved.

The mercaptan removal catalyst is suitable for removing mercaptan and/or diene in liquefied petroleum gas, FCC gasoline, catalytic pyrolysis gasoline and/or coker gasoline; the catalyst has good selectivity. The loss of octane value RON of the gasoline is about 0.3-0.4 point. The catalyst has high activity for removing mercaptan, high selectivity for hydrogenating diolefin, low saturation rate of olefin and low loss of octane number.

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 the catalyst

Preparing a nickel, zinc, lithium 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. Catalyst 2 was prepared according to the same method 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. Catalyst 3 was prepared according to the same method as in example 1.

Example 4

The nickel-doped lanthanum ferrite was prepared as in example 1 except that 280g of sodium polyacrylate was added, and the silica-alumina carrier was prepared as in example 1, wherein the silica-alumina carrier contained 8.4 wt% of silica, 2.6 wt% of nickel-doped lanthanum ferrite, and 2.5 wt% of potassium, the mesopores of the carrier accounted for 49.3% of the total pores, and the macropores accounted 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 catalyst was prepared in the same manner 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. Preparation of comparative catalyst 1

Preparing a nickel, zinc, lithium and molybdenum-containing solution to impregnate a 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. Preparation of comparative catalyst 2

Preparing a nickel, zinc, lithium and molybdenum-containing solution to impregnate the 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, the hydrogen-oil volume ratio is 300, 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 mercaptan removal and diene reaction.The sulfur content of FCC raw gasoline is 487 mug/g, the mercaptan sulfur is 42.8 mug/g, the arsenic content is 31ppb, the olefin content is 35.4 v%, and the RON is 90.1. The reaction process conditions are as follows: the reactor temperature is 130 ℃, 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%

Examples/comparative examples	Molybdenum oxide	Nickel oxide	Zinc oxide	Lithium oxide
					Example 1	13.6	10.9	2.4	0.1
Example 2	15.7	9.8	1.6	0.2
					Example 3	11.2	13.7	0.8	0.1
Example 4	9.5	11.6	2.8	0.2
					Comparative example 1	13.6	10.9	2.4	0.1
Comparative example 2	13.6	10.9	2.4	0.1

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	0.3	42.3	0.3	98.4
Example 2	0.3	42.1	0.3	98.2
					Example 3	0.4	41.9	0.4	98.0
Example 4	0.4	42.0	0.4	98.3
					Comparative example 1	15	31.4	4.2	85.1
Comparative example 2	12	34.8	3.5	89.7

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	0.3	41.9	0.3	98.2
Example 2	0.4	42.0	0.3	98.3

The reaction result shows that the olefin content is basically unchanged, the loss of the reaction octane number is 0.3-0.4, the catalyst has high diene hydrogenation selectivity and mercaptan removal activity, good arsenic resistance and sulfur resistance and low loss of the octane number. 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. The FCC gasoline selective hydrogenation catalyst is characterized by comprising a silicon oxide-aluminum oxide carrier and metal active components of nickel, molybdenum, zinc and lithium loaded on the carrier, wherein the content of nickel oxide is 2-15 wt%, the content of molybdenum oxide is 2-18 wt%, the content of zinc oxide is 0.1-5 wt%, and the content of lithium oxide is 0.1-2.5 wt% based on the weight of the catalyst; the content of a silicon oxide-aluminum oxide carrier is 65-85 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 0.1-2.5 wt% of potassium, mesoporous pores of the carrier account for 3-75% of total pores, macroporous pores account for 1.5-60% of the total pores, and micropores, mesopores and macropores in the carrier are distributed unevenly; 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 and the alumina precursor, adding a potassium source, extruding, forming, drying and roasting to obtain the silica-alumina carrier.

2. The FCC gasoline selective hydrogenation catalyst of claim 1, wherein the catalyst comprises the following components, based on total weight: the content of nickel oxide is 4-15 wt%, and the content of molybdenum oxide is 5-16 wt%.

3. The selective hydrogenation catalyst for FCC gasoline according to claim 1, wherein the mesopores of the carrier account for 3-65% of the total pore and the macropores account for 1.5-50% of the total pore.

4. The FCC gasoline selective hydrogenation catalyst of 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 selective hydrogenation catalyst of 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 selective hydrogenation catalyst according to any one of claims 1 to 5, wherein the nickel-doped lanthanum ferrite is prepared by a method comprising: 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 selective hydrogenation catalyst for FCC gasoline according to any one of claims 1 to 5, wherein the preparation method of the catalyst 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 selective hydrogenation catalyst of claim 7, wherein the catalyst is prepared by: preparing a silicon oxide-alumina carrier impregnated with a solution containing nickel, zinc, lithium 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.