Catalytic cracking gasoline selective hydrodesulfurization catalyst and preparation method and application thereof

Abstract

The invention provides a catalytic cracking gasoline selective hydrodesulfurization catalyst and a preparation method and application thereof, the catalyst comprises a SiO2 / gamma-Al2O3 composite carrier, and a main active metal sulfide and an auxiliary active metal sulfide loaded on the composite carrier; in the SiO2 / gamma-Al2O3 composite carrier, SiO2 covers the inner surface and the outer surface of gamma-Al2O3, and the content of SiO2 is 1.0-10.0 wt% based on the total weight of the composite carrier; based on the total weight of the catalyst, the content of the main active metal in terms of oxide is 2.0-20.0 wt%, and the content of the auxiliary active metal in terms of oxide is 1.0-10.0 wt%; in the catalyst, the concentration of the main active metal-auxiliary active metal-sulfur active sites is 0.18-0.50 mmol / g. The catalyst has both high desulfurization activity and low olefin saturation activity for high-sulfur FCC gasoline.

Description

Technical Field

[0001] The invention relates to a catalytic cracking gasoline selective hydrodesulfurization catalyst and a preparation method and application thereof, belonging to the technical field of selective hydrodesulfurization. Background Art

[0002] FCC gasoline is made of C4-C 12 FCC gasoline is a mixture of hydrocarbons and trace amounts of sulfides, oxides and metal arsenides. According to the differences in crude oil properties and processing routes of various refineries, FCC gasoline is a mixture of 18-55v% olefins, 12-20v% aromatics and alkanes, and the octane number characteristics of each component are aromatics>olefins≈isoalkanes>alkanes. Generally, FCC gasoline with high sulfur, high olefin content and low octane number accounts for a high proportion, while the proportion of alkylate, isomerized oil and reforming oil with low sulfur content, low olefin content and high octane number is low, which requires the cleanliness of FCC gasoline to simultaneously carry the triple mission goals of desulfurization, olefin reduction and octane maintenance.

[0003] Gasoline hydrodesulfurization catalysts can use a variety of carriers. For example, Okamoto et al. (Applied Catalysis A: General, 2002, 226: 115-127) studied the carrier effect of CoMoS catalyst hydrodesulfurization activity (HDS) and olefin hydrogenation saturation activity (HYD). The results show that the HDS activity is positively correlated with the amount of CoSx species located at the edge of MoS2 (CoMoS concentration); CoMoS supported by different carriers (such as Al2O3, SiO2, TiO2 and ZrO2) has the same HYD activity, but CoMoS supported by SiO2 has a higher HDS activity, so CoMoS supported by SiO2 has a higher HDS activity and selectivity. The defects of this technology or the shortcomings of the present invention: Although the CoMoS catalyst supported by SiO2 has the highest HDS activity, the preparation procedure of the SiO2 carrier is complicated and not convenient for industrial production.

[0004] CN102335612A discloses a selective hydrodesulfurization catalyst, which uses cobalt and molybdenum as active components and SiO2 and Al2O3 as carriers. The carrier is prepared by molding, drying and calcining pseudo-boehmite and silicon oxide precursor (or silicon-containing pseudo-boehmite or pseudo-boehmite, silicon oxide precursor and alkaline earth metal soluble salt). The prepared catalyst has an average olefin saturation rate of 10% for FCC gasoline with a sulfur content of 430 mg / kg and an olefin content of 45.25v%, a selectivity factor of more than 18% and an octane number loss of no more than 0.8. The defects of this technology or the shortcomings of the present invention are as follows: the conventional preparation process of SiO2 / Al2O3 composite carrier using pseudo-boehmite and silicon oxide precursor as raw materials and kneading and molding is adopted. There is a certain degree of random distribution and mutual embedding between SiO2 and Al2O3 in the prepared carrier, and the Al2O3 on the pore surface is not uniform. 3+ Most species, the surface Al 3+ There is a strong interaction between the species and the cobalt and molybdenum active metal precursors, and the impregnation solution of the cobalt and molybdenum active metal precursors does not contain a complexing agent, which will inevitably cause Al 3+ There is a strong interaction between the species and the active metal precursors of cobalt and molybdenum, which is not conducive to the sulfidation of cobalt and molybdenum to form a highly active cobalt-molybdenum-sulfur active phase. Therefore, the catalyst produced by this technology targets FCC gasoline, and the average sulfur content of its hydrogenated gasoline product is as high as 60.2 mg / kg, which is far from the clean gasoline quality standard requirement of no more than 10 mg / kg.

[0005] CN114425455A discloses a method for preparing SiO2 coated alumina catalytic carrier material, wherein the preparation method of the catalytic carrier material comprises first preparing a coating liquid containing silicide (one or more of silica sol, water glass, white carbon black), organic carbon precursor (one or more of sugar, flour, polyvinyl alcohol, polyethylene glycol, cellulose ether) and water; then introducing the coating liquid onto the carrier substrate, and further drying and roasting to obtain a carrier with high wear resistance. The defects of this technology or the shortcomings relative to the present invention are as follows: the coating liquid (containing silicide, organic carbon precursor and water) is a suspension liquid, which is difficult to enter the inner surface of the pores of alumina, and most of it is coated on the outer surface of the carrier substrate (in the catalytic material prepared with the carrier, the active metal is distributed in the center and less at the edge, which is like an ink bottle mouth), which is not conducive to the reaction and diffusion of the reactants and their product catalysts.

[0006] Therefore, providing a novel catalytic cracking gasoline selective hydrodesulfurization catalyst and its preparation method and application has become a technical problem that needs to be solved urgently in the field. Summary of the invention

[0007] In order to solve the above-mentioned shortcomings and deficiencies, an object of the present invention is to provide a catalytic cracking gasoline selective hydrodesulfurization catalyst.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned catalytic cracking gasoline selective hydrodesulfurization catalyst.

[0009] Another object of the present invention is to provide the use of the above-mentioned catalytic cracking gasoline selective hydrodesulfurization catalyst in the selective hydrodesulfurization of FCC gasoline.

[0010] In order to achieve the above objectives, on the one hand, the present invention provides a catalytic cracking gasoline selective hydrodesulfurization catalyst, wherein the catalytic cracking gasoline selective hydrodesulfurization catalyst comprises a SiO2 / γ-Al2O3 composite carrier and a main active metal sulfide and a co-active metal sulfide supported on the composite carrier;

[0011] In the SiO2 / γ-Al2O3 composite carrier, SiO2 covers the inner surface (the inner surface of γ-Al2O3 refers to the surface of the pore structure contained in γ-Al2O3) and the outer surface of γ-Al2O3, and the SiO2 content is 1.0-10.0wt%, preferably 2.0-9.0wt%, based on the total weight of the composite carrier as 100%;

[0012] Based on the total weight of the catalyst as 100%, the content of the main active metal in terms of oxide is 2.0-20.0wt%, preferably 7.0-15.0wt%, and the content of the auxiliary active metal in terms of oxide is 1.0-10.0wt%, preferably 2.0-9.0wt%;

[0013] In the catalytic cracking gasoline selective hydrodesulfurization catalyst, the concentration of the main active metal-co-active metal-sulfur active site is 0.18-0.50 mmol / g, preferably 0.20-0.50 mmol / g. In the catalytic cracking gasoline selective hydrodesulfurization catalyst provided by the present invention, since SiO2 covers the inner and outer surfaces of γ-Al2O3, the main active metal oxide and the co-active metal oxide are actually loaded on the surface of SiO2.

[0014] As a specific embodiment of the above catalyst of the present invention, based on the total weight of the catalyst as 100%, the content of SiO2 is 0.5-9.5wt%, preferably 1.5-8.5wt%.

[0015] As a specific embodiment of the catalyst described above, the SiO2 / γ-Al2O3 composite carrier has a water absorption rate of 90-120%, preferably 100-110%; a mechanical strength of 10-20 N / mm, preferably 12-18 N / mm; a BET specific surface area of ​​290-360 m 2 / g, preferably 300-350m 2 / g; the pore volume is 1.0-1.4mL / g, preferably 1.1-1.3mL / g.

[0016] As a specific embodiment of the above-mentioned catalyst of the present invention, the total acid content of the SiO2 / γ-Al2O3 composite carrier is 0.005-0.05 mmol / g.

[0017] As a specific embodiment of the above catalyst of the present invention, the main active metal includes Mo and the like, and the auxiliary active metal includes Co and the like.

[0018] On the other hand, the present invention also provides a method for preparing the above-mentioned catalytic cracking gasoline selective hydrodesulfurization catalyst, wherein the preparation method comprises:

[0019] Step (1): fully kneading, shaping, drying and calcining alumina raw powder, extrusion aid and aqueous solution of peptizing agent to obtain γ-Al2O3 carrier;

[0020] Step (2): preparing an aqueous solution of sodium silicate and impregnating it onto a γ-Al2O3 carrier, and subjecting the mixture to aging, ultrasonic washing with acidic water, decantation, drying, and calcination to obtain a SiO2 / γ-Al2O3 composite carrier;

[0021] Step (3): preparing a co-impregnation solution containing a complexing agent, an auxiliary active metal salt and a main active metal salt;

[0022] Step (4): impregnating an equal volume of the co-impregnation liquid onto a SiO2 / γ-Al2O3 composite carrier, and then subjecting the carrier to aging, drying, and temperature-raising sulfurization to obtain a catalytic cracking gasoline selective hydrodesulfurization catalyst.

[0023] As a specific embodiment of the preparation method described above of the present invention, in step (1), the alumina raw powder includes pseudo-boehmite powder, etc., the extrusion aid includes one or a combination of sesbania powder, polyacrylamide, graphite and lubricating oil, etc., preferably one of sesbania powder, polyacrylamide, graphite, etc., and the peptizing agent includes one or a combination of nitric acid, hydrochloric acid, acetic acid and citric acid, etc., preferably one of nitric acid, hydrochloric acid, acetic acid, etc.

[0024] As a specific embodiment of the preparation method described above, based on the total dry weight of the γ-Al2O3 carrier, the weight contents of the extrusion aid and the peptizer are 4-10wt% and 2-5wt%, respectively, preferably 5-9wt% and 3-4wt%, respectively.

[0025] As a specific embodiment of the preparation method described above of the present invention, wherein, in step (1), the calcination is performed at 550-600° C. for 4-6 hours.

[0026] As a specific embodiment of the preparation method described above, the water absorption rate, strength, BET specific surface area and pore volume of the γ-Al2O3 carrier are 90-150%, 8-20N / mm2, 290-360m3, respectively. 2 / g and 0.8-1.6mL / g, preferably 100-140%, 10-15N / mm, 300-350m / g, respectively 2 / g and 0.9-1.5mL / g.

[0027] As a specific embodiment of the preparation method described above of the present invention, in step (2), the ratio of the molar numbers of silicon dioxide (SiO2) to sodium oxide (Na2O) in the sodium silicate [modulus (n)] is 1.5-3.0, preferably 1.7-2.8.

[0028] As a specific embodiment of the preparation method described above of the present invention, wherein, in step (2), the acid used in the acidic water is one of nitric acid, hydrochloric acid, acetic acid, sulfuric acid, etc., preferably one of nitric acid, hydrochloric acid, acetic acid, etc.

[0029] As a specific embodiment of the preparation method described above of the present invention, wherein, in step (2), the calcination is performed at 550-600° C. for 4-6 hours.

[0030] As a specific embodiment of the preparation method described above of the present invention, in step (3), in the co-impregnation solution, the molar ratio of the complexing agent to the auxiliary active metal salt is 1.2-2.2:1, preferably 1.5-1.7:1.

[0031] As a specific embodiment of the preparation method described above in the present invention, in step (3), the pH value of the co-impregnation solution is greater than 8.1, preferably greater than 8.2.

[0032] As a specific embodiment of the preparation method described above of the present invention, wherein, in step (3), the complexing agent includes one of ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid, ethylenediamine, cyclohexanediaminetetraacetic acid, citric acid and ethylene glycol, and is preferably one of ethylenediaminetetraacetic acid, nitrilotriacetic acid and cyclohexanediaminetetraacetic acid.

[0033] As a specific embodiment of the preparation method described above in the present invention, in step (3), the auxiliary active metal salt includes one or a combination of nitrates, acetates and carbonates of auxiliary active metals, and the main active metal salt includes one or a combination of ammonium salts and thioammonium salts of the main active metals.

[0034] When the auxiliary active metal, that is, the auxiliary metal is Co, its salt is one or a combination of cobalt nitrate, cobalt acetate, cobalt carbonate, etc., preferably cobalt nitrate or cobalt acetate; when the main active metal is Mo, its salt is one or more of ammonium heptamolybdate, ammonium tetramolybdate and ammonium tetrathiomolybdate, etc., preferably ammonium heptamolybdate or ammonium tetrathiomolybdate.

[0035] As a specific embodiment of the preparation method described above, in step (4), the maximum vulcanization temperature is 280-360°C, preferably 300-360°C; the cumulative time of heating and vulcanization is 20-100h, preferably 25-50h; the vulcanization pressure is 1.0-3.0MPa, preferably 1.5-2.5MPa; the vulcanized oil volume space velocity is 1.0-3.0h -1 , preferably 1.0-2.0h -1 ; The hydrogen / oil volume ratio is 200:1-500:1, preferably 250:1-350:1.

[0036] As a specific embodiment of the preparation method described above of the present invention, wherein, in step (4), the sulfurizing agent used for the sulfurization includes one or a combination of dimethyl disulfide, carbon disulfide, methyl mercaptan, ethyl mercaptan and sulfide (such as methyl sulfide), preferably dimethyl disulfide or carbon disulfide.

[0037] In another aspect, the present invention also provides the use of the above-mentioned catalytic cracking gasoline selective hydrodesulfurization catalyst in the selective hydrodesulfurization of FCC gasoline.

[0038] Compared with the prior art, the beneficial technical effects that can be achieved by the present invention include:

[0039] (1) The present invention first prepares a γ-Al2O3 carrier, then prepares an aqueous solution of sodium silicate and impregnates it onto the γ-Al2O3 carrier. At this time, the sodium silicate is loaded on the inner and outer surfaces of the γ-Al2O3 by impregnation. Finally, the impregnated product is aged, ultrasonically washed with acidic water, decanted, dried, and calcined in sequence. During the calcination process, the sodium silicate is converted into SiO2 and covers the inner and outer surfaces of the γ-Al2O3, thereby obtaining a SiO2 / γ-Al2O3 composite carrier, that is, most of the inner and outer surfaces of the pores of the composite carrier are covered with SiO2. The SiO2 covering the inner and outer surfaces of the γ-Al2O3 in the SiO2 / γ-Al2O3 composite carrier creates a prerequisite for the selective loading of salts of metals such as main active metals and auxiliary active metals on the SiO2 surface of the composite carrier.

[0040] (2) Based on the improved SiO2 / γ-Al2O3 composite carrier, the present invention adds a complexing agent (complexing agent and main and auxiliary active metal cation species, mainly auxiliary active metal cation species and Al2O3 on the surface of SiO2 / γ-Al2O3 composite carrier not covered by SiO2) to the co-impregnation solution when preparing the catalytic cracking gasoline selective hydrodesulfurization catalyst. 3+ The invention discloses a method for selectively loading the main active metal salt and the auxiliary metal salt (such as metal salts of Co and Mo) on the surface of SiO2 in the composite carrier by adjusting the molar ratio of the complexing agent to the auxiliary metal and the pH value of the co-impregnation solution. In the subsequent sulfurization process, a large number of highly active and highly selective main active metal-auxiliary active metal-sulfur (such as CoMoS) active sites can be formed, so that the catalytic cracking gasoline selective hydrodesulfurization catalyst has both high desulfurization activity and low olefin saturation activity for high-sulfur FCC gasoline. DETAILED DESCRIPTION

[0041] It should be noted that the term "comprises" and any variations thereof in the specification and claims of the present invention are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or devices.

[0042] "Scope" disclosed in the present invention is given in the form of lower limit and upper limit. It can be one or more lower limits, and one or more upper limits respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges defined in this way are combinable, i.e. any lower limit can be combined with any upper limit to form a range. For example, for a specific parameter, a range of 60-120 and 80-110 is listed, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and the maximum range values ​​listed are 3, 4 and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.

[0043] In the present invention, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed in the present invention, and "0-5" is just an abbreviation of these numerical combinations.

[0044] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0045] In the present invention, unless otherwise specified, all technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0046] In the present invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0047] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with tables and examples. The following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0048] Carrier Examples and Comparative Examples

[0049] Example 1

[0050] In this embodiment, a SiO2 / γ-Al2O3 composite carrier (ZAT-1) was prepared. First, 300 g of pseudo-boehmite powder and 15.0 g of sesbania powder were mixed evenly, and then 9.0 g of concentrated nitric acid (65 wt%) and 540 g of deionized water were added, and after being fully kneaded, they were extruded into 1.5-3.0 mm clover-shaped strips in an extruder, dried at 120° C. for about 4 h, calcined at 520° C. for about 4 h, cooled and sieved to prepare a 3-10 mm long γ-Al2O3 carrier (ZAT-D1, the total dry weight of the prepared γ-Al2O3 was 225 g). Then, an aqueous solution of sodium silicate (n=2.1) was prepared and impregnated on 100 g of ZAT-D1. After aging overnight, it was ultrasonically treated with a 2.5 wt% hydrochloric acid solution at 30°C for 20 min and decanted. This was repeated three times. Then, it was ultrasonically treated with deionized water at 30°C for 20 min, decanted, dried at 120°C for 4 h, and calcined at 550°C for 6 h to obtain ZAT-1.

[0051] Example 2

[0052] This example prepares a SiO2 / γ-Al2O3 composite carrier (ZAT-2). The difference between this example and Example 1 is that: an aqueous solution of sodium silicate (n=2.2) is impregnated on 100g of ZAT-D1; after aging overnight, it is ultrasonically treated with a 3.0wt% nitric acid aqueous solution; after the second decantation, it is first dried at 110°C for 6h and then calcined at 580°C for 5h.

[0053] Example 3

[0054] This example prepares a SiO2 / γ-Al2O3 composite carrier (ZAT-3). The difference between this example and Example 1 is that: an aqueous solution of sodium silicate (n=2.0) is impregnated on 100g of ZAT-D1; after aging overnight, it is ultrasonically treated with a 4.0wt% acetic acid aqueous solution; after the second decantation, it is first dried at 130°C for 3h and then calcined at 600°C for 4h.

[0055] Example 4

[0056] This example prepares a SiO2 / γ-Al2O3 composite carrier (ZAT-4). The difference between this example and Example 1 is that an aqueous solution of sodium silicate (n=1.8) is impregnated on 100 g of ZAT-D1.

[0057] Comparative Example 1

[0058] This comparative example prepares a SiO2 / γ-Al2O3 composite carrier (ZAT-D2). The difference between this ZAT-D2 and ZAT-D1 in Example 1 is that: ZAT-D2 is prepared by using silicon-containing pseudo-boehmite powder, that is, the preparation method of ZAT-D2 includes: first, 300g of silicon-containing pseudo-boehmite powder and 15.0g of sesbania powder are mixed evenly, and then 9.0g of concentrated nitric acid (65wt%) and 540g of deionized water are added, and after fully kneading, they are extruded into 1.5-3.0mm clover-shaped strips in an extruder, dried at 120℃ for about 4h, calcined at 520℃ for about 4h, cooled and sieved to prepare a 3-10mm long SiO2 / γ-Al2O3 composite carrier (ZAT-D2, whose total dry weight is 225g).

[0059] The SiO2 content, water absorption, strength, BET specific surface area, pore volume and total acid content in the above-mentioned carriers (ZAT-1 to ZAT-4, ZAT-D1 and ZAT-D2) were measured by X-ray fluorescence method, saturation impregnation method, the method specified in Q / SH-361926, the method specified in GB / T-5816, the method specified in Q / SH-361913 and ammonia programmed temperature desorption method respectively. The composition and physicochemical properties of the above-mentioned carriers are shown in Table 1 below.

[0060] Table 1 Carrier composition and physicochemical properties

[0061]

[0062] It can be seen from Table 1 that compared with ZAT-D1 and ZAT-D2, the water absorption rate, strength, BET specific surface area and pore volume of ZAT-1 to ZAT-4 did not change much, but the total surface acid content decreased significantly, which indicates that the Al on the surface of the ZAT-1 to ZAT-4 carriers provided in the embodiments of the present invention 3+The results show that the inner and outer surfaces of the SiO2 / γ-Al2O3 composite carrier provided or used in the embodiments of the present invention are mostly covered by SiO2. It can also be seen from Table 1 that compared with ZAT-D1 made from pseudo-boehmite powder, ZAT-D2 made from silicon-containing pseudo-boehmite powder contains SiO2, so it can expose less surface Al2O3. 3+ The acid content of the species, i.e., ZAT-D2, is relatively small.

[0063] Catalyst Examples and Comparative Examples

[0064] Example 5

[0065] In this embodiment, catalyst CAT-1 is prepared, and the preparation method includes the following specific steps:

[0066] preparing a co-impregnation solution containing EDTA, cobalt nitrate and ammonium heptamolybdate, wherein the molar ratio of EDTA to cobalt nitrate is 1.5:1, and adjusting the pH of the co-impregnation solution to 9.8 by adding concentrated ammonia water;

[0067] The co-impregnation liquid was impregnated into ZAT-1 in equal volume, and after conventional aging and drying procedures, a semi-finished product was obtained, which was loaded into a 200 mL fixed bed reactor for vulcanization. The vulcanizing oil was straight-run naphtha, the vulcanizing agent was carbon disulfide, the concentration of carbon disulfide was 1.5 wt.% based on the total weight of the vulcanizing oil, the vulcanization pressure was 2.0 MPa, the hydrogen-to-oil volume ratio was 300:1, and the vulcanizing oil volume space velocity was 1.5 h -1 The heating process is as follows: first, in a nitrogen atmosphere, the temperature is increased from room temperature to 180°C at a heating rate of 30°C / h, and the temperature is maintained at this temperature for 2 hours; then, the nitrogen is switched to hydrogen, the sulfide oil is injected, and the temperature is increased from 180°C to 230°C at a heating rate of 20°C / h, and the temperature is maintained at this temperature for 4 hours; finally, the temperature is increased from 230°C to 350°C at a heating rate of 20°C / h, and the temperature is maintained at this temperature for 4 hours to obtain CAT-1.

[0068] Example 6

[0069] In this embodiment, catalyst CAT-2 is prepared, and the preparation method includes the following specific steps:

[0070] preparing a co-impregnation solution containing cyclohexanediaminetetraacetic acid, cobalt nitrate and ammonium heptamolybdate, wherein the molar ratio of cyclohexanediaminetetraacetic acid to cobalt nitrate is 2.0:1, and adjusting the pH of the co-impregnation solution to 8.8 by adding concentrated ammonia water;

[0071] The co-impregnation liquid was impregnated into ZAT-2 in equal volume, and after conventional aging and drying procedures, a semi-finished product was obtained, which was loaded into a 200 mL fixed bed reactor for vulcanization. The vulcanizing oil was straight-run naphtha, the vulcanizing agent was dimethyl disulfide, the concentration of dimethyl disulfide was 1.5 wt.% based on the total weight of the vulcanizing oil, the vulcanization pressure was 1.5 MPa, the hydrogen-to-oil volume ratio was 250:1, and the vulcanizing oil volume space velocity was 1.2 h -1 The heating process is as follows: first, in a nitrogen atmosphere, the temperature is increased from room temperature to 180°C at a heating rate of 30°C / h, and the temperature is maintained at this temperature for 2 hours. Then, the nitrogen is switched to hydrogen, and the sulfide oil is injected. The temperature is increased from 180°C to 230°C at a heating rate of 20°C / h, and the temperature is maintained at this temperature for 4 hours. Finally, the temperature is increased from 230°C to 360°C at a heating rate of 20°C / h, and the temperature is maintained at this temperature for 2 hours to obtain CAT-2.

[0072] Example 7

[0073] The catalyst (CAT-3) was prepared in this embodiment, and the preparation method included the following specific steps:

[0074] preparing a co-impregnation solution containing nitrotriacetic acid, cobalt acetate and ammonium heptamolybdate, wherein the molar ratio of nitrotriacetic acid to cobalt acetate is 2.2:1, and adjusting the pH of the co-impregnation solution to 9.0 by adding concentrated ammonia water;

[0075] The co-impregnation liquid was impregnated into ZAT-3 in equal volume, and after conventional aging and drying procedures, a semi-finished product was obtained, which was loaded into a 200 mL fixed bed reactor for vulcanization. The sulfiding oil was straight-run naphtha, the vulcanizing agent was methyl mercaptan, the concentration of methyl mercaptan was 1.5 wt.% based on the total weight of the sulfiding oil, the vulcanization pressure was 1.6 MPa, the hydrogen-to-oil volume ratio was 270:1, and the sulfiding oil volume space velocity was 1.6 h -1 The heating process is as follows: first, in a nitrogen atmosphere, the temperature is increased from room temperature to 180°C at a heating rate of 30°C / h, and the temperature is maintained at this temperature for 2 hours. Then, the nitrogen is switched to hydrogen, and the sulfide oil is injected. The temperature is increased from 180°C to 230°C at a heating rate of 20°C / h, and the temperature is maintained at this temperature for 4 hours. Finally, the temperature is increased from 230°C to 340°C at a heating rate of 20°C / h, and the temperature is maintained at this temperature for 5 hours to obtain CAT-3.

[0076] Example 8

[0077] The catalyst (CAT-4) was prepared in this embodiment, and the preparation method included the following specific steps:

[0078] preparing a co-impregnation solution containing ethylenediamine, cobalt acetate and ammonium tetramolybdate, wherein the molar ratio of ethylenediamine to cobalt acetate is 1.6:1, and adjusting the pH of the co-impregnation solution to 9.8 by adding concentrated ammonia water;

[0079] The co-impregnation liquid was impregnated into ZAT-4 in equal volume, and after conventional aging and drying procedures, a semi-finished product was obtained, which was loaded into a 200 mL fixed bed reactor for vulcanization. The vulcanizing oil was straight-run naphtha, the vulcanizing agent was ethyl mercaptan, the concentration of ethyl mercaptan was 1.5 wt.% based on the total weight of the vulcanizing oil, the vulcanization pressure was 1.9 MPa, the hydrogen-to-oil volume ratio was 320:1, and the vulcanizing oil volume space velocity was 1.8 h -1 The heating process is as follows: first, in a nitrogen atmosphere, the temperature is increased from room temperature to 180°C at a heating rate of 30°C / h, and the temperature is maintained at this temperature for 2 hours. Then, the nitrogen is switched to hydrogen, and the sulfide oil is injected. The temperature is increased from 180°C to 230°C at a heating rate of 20°C / h, and the temperature is maintained at this temperature for 4 hours. Finally, the temperature is increased from 230°C to 345°C at a heating rate of 20°C / h, and the temperature is maintained at this temperature for 4.5 hours to obtain CAT-4.

[0080] Example 9

[0081] The catalyst (CAT-5) was prepared in this embodiment, and the preparation method included the following specific steps:

[0082] preparing a co-impregnation solution containing EDTA, cobalt nitrate and ammonium heptamolybdate, wherein the molar ratio of EDTA to cobalt nitrate is 1.9:1, and adjusting the pH of the co-impregnation solution to 9.8 by adding concentrated ammonia water;

[0083] The co-impregnation liquid was impregnated into ZAT-1 in equal volume, and after conventional aging and drying procedures, a semi-finished product was obtained, which was loaded into a 200 mL fixed bed reactor for vulcanization. The vulcanizing oil was straight-run naphtha, the vulcanizing agent was dimethyl sulfide, the concentration was 1.5 wt.%, the vulcanization pressure was 2.4 MPa, the hydrogen-to-oil volume ratio was 340:1, and the vulcanizing oil volume space velocity was 1.9 h -1 The heating process is: first, in a nitrogen atmosphere, the temperature is increased from room temperature to 180°C at a heating rate of 30°C / h, and the temperature is kept constant for 2 hours. Then, the nitrogen is switched to hydrogen, and the sulfide oil is injected. The temperature is increased from 180°C to 230°C at a heating rate of 20°C / h, and the temperature is kept constant for 4 hours. Finally, the temperature is increased from 230°C to 355°C at a heating rate of 20°C / h, and the temperature is kept constant for 3.5 hours to obtain CAT-5.

[0084] Comparative Example 2

[0085] The catalyst (CAT-D1) prepared in this comparative example is prepared by a method different from that of Example 5, except that the pH of the co-impregnation solution containing EDTA, cobalt nitrate and ammonium heptamolybdate is 7.5.

[0086] Comparative Example 3

[0087] The catalyst (CAT-D2) prepared in this comparative example has a preparation method different from that of Example 5, except that ZAT-D2 is used as a carrier.

[0088] Comparative Example 4

[0089] The catalyst (CAT-D3) prepared in this comparative example has a preparation method different from that of Example 5, except that ZAT-D2 is used as a carrier and the co-impregnation solution does not contain a complexing agent.

[0090] Comparative Example 5

[0091] The catalyst (CAT-D4) prepared in this comparative example has a preparation method different from that of Example 5, except that ZAT-D1 is used as a carrier and the co-impregnation solution does not contain a complexing agent.

[0092] Comparative Example 6

[0093] The catalyst (CAT-D5) prepared in this comparative example is different from that in Example 5 in that no complexing agent is used.

[0094] Comparative Example 7

[0095] The catalyst (CAT-D6) prepared in this comparative example is different from that in Example 5 in that ZAT-D1 is used.

[0096] Comparative Example 8

[0097] The catalyst (CAT-D7) prepared in this comparative example is different from that in Example 5 except that the molar ratio of the complexing agent to the auxiliary metal salt is 1.0:1.

[0098] The MoO3 content, CoO content, SiO2 content and CoMoS active site concentration in the above catalysts (CAT-1 to CAT-5 and CAT-D1 to CAT-D7) were measured by atomic absorption spectrometry, X-ray fluorescence spectrometry and CO infrared spectroscopy, and the results are shown in Table 2 below.

[0099] Table 2 Catalyst composition and physicochemical properties

[0100]

[0101] It can be seen from Table 2 that compared with the comparative agent, the catalyst provided by the embodiment of the present invention has a higher concentration of CoMoS active sites for selective hydrodesulfurization. This is attributed to the fact that when preparing the catalytic cracking gasoline selective hydrodesulfurization catalyst in the embodiment of the present invention, a complexing agent is added to the co-impregnation liquid, and the complexing agent and Co 2+ and Al in SiO2 / γ-Al2O3 composite carrier 3+Preferential complexation and selective loading of Co and Mo metal salts on the SiO2 surface in the composite carrier can be achieved by adjusting the molar ratio of the complexing agent to the auxiliary metal and the pH value of the co-impregnation solution. In the subsequent sulfurization process, more highly active and highly selective CoMoS active sites can be formed.

[0102] Catalyst Performance Evaluation Example

[0103] This evaluation example adopts a 200mL fixed bed reactor, with FCC gasoline having a sulfur content of 1000mg / kg, an olefin content of 50v%, and a research octane number (RON) of 91.5 as the raw material, and the reactor inlet temperature is 230°C, the reaction pressure is 1.7MPa, and the volume space velocity is 2.6h -1 Under the catalyst evaluation conditions of 1:1 and 2:1 hydrogen-to-oil volume ratio, CAT-1 to CAT-5 and CAT-D1 to CAT-D7 were compared and evaluated, and the total sulfur content of catalytic cracking gasoline and its hydroprocessing products was determined according to SH / T 0689-2000, the RON of catalytic cracking gasoline and its hydroprocessing products was determined according to GB / T 5487-1995, and the olefin content of catalytic cracking gasoline and its hydroprocessing products was determined according to GB / T 11132. The evaluation results are shown in Table 3 below.

[0104] Table 3 Hydrogenated gasoline product analysis data

[0105] project Total sulfur / mg / kg Olefin saturation rate / % RON loss CAT-1 9.2 8.0 1.3 CAT-2 8.5 7.2 1.2 CAT-3 9.0 7.5 1.3 CAT-4 7.2 7.0 1.2 CAT-5 9.6 8.5 1.4 CAT-D1 29.8 9.0 1.6 CAT-D2 248.8 10.0 1.7 CAT-D3 510.5 15.0 2.5 CAT-D4 671.7 18.1 3.5 CAT-D5 35.0 8.8 1.5 CAT-D6 235.2 10.5 1.8 CAT-D7 250.5 10.1 1.7

[0106] As can be seen from Table 3, for the above FCC gasoline feedstock, compared with the comparative agent, the hydrogenated gasoline product obtained by the catalyst provided in the embodiment of the present invention has a low sulfur content (<10 mg / kg) and olefin saturation rate (<9.0%), and a small RON loss (<1.6). This is attributed to the fact that the catalyst obtained in the embodiment of the present invention has a higher concentration of selective hydrodesulfurization CoMoS active sites.

[0107] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other and with each other, and with each other.

Claims

1. A catalytic cracking gasoline selective hydrodesulfurization catalyst, characterized in that: The catalytic cracking gasoline selective hydrodesulfurization catalyst comprises a SiO2 / γ-Al2O3 composite carrier and a main active metal sulfide and a co-active metal sulfide supported on the composite carrier; In the SiO2 / γ-Al2O3 composite carrier, SiO2 covers the inner and outer surfaces of γ-Al2O3, and the SiO2 content is 1.0-10.0wt% based on the total weight of the composite carrier as 100%; Based on the total weight of the catalyst being 100%, the content of the main active metal in terms of oxide is 2.0-20.0wt%, and the content of the auxiliary active metal in terms of oxide is 1.0-10.0wt%; In the catalytic cracking gasoline selective hydrodesulfurization catalyst, the concentration of the main active metal-co-active metal-sulfur active site is 0.18-0.50 mmol / g.

2. The catalyst according to claim 1, characterized in that The water absorption rate of SiO2 / γ-Al2O3 composite carrier is 90-120%, the mechanical strength is 10-20N / mm, and the BET specific surface area is 290-360m 2 / g, pore volume is 1.0-1.4mL / g; Preferably, the total acid content of the SiO2 / γ-Al2O3 composite carrier is 0.005-0.05 mmol / g.

3. The catalyst according to claim 1 or 2, characterized in that The main active metal includes Mo, and the auxiliary active metal includes Co.

4. The method for preparing the selective hydrodesulfurization catalyst for catalytic cracking gasoline according to any one of claims 1 to 3, characterized in that: The preparation method comprises: Step (1): fully kneading, shaping, drying and calcining alumina raw powder, extrusion aid and aqueous solution of peptizing agent to obtain γ-Al2O3 carrier; Step (2): preparing an aqueous solution of sodium silicate and impregnating it onto a γ-Al2O3 carrier, followed by aging, ultrasonic washing with acidic water, decantation, drying, and calcination to obtain a SiO2 / γ-Al2O3 composite carrier; Step (3): preparing a co-impregnation solution containing a complexing agent, an auxiliary active metal salt and a main active metal salt; Step (4): impregnating an equal volume of the co-impregnation liquid onto the SiO2 / γ-Al2O3 composite carrier, and then subjecting the mixture to aging, drying, and temperature-raising sulfurization to obtain a catalytic cracking gasoline selective hydrodesulfurization catalyst.

5. The preparation method according to claim 4, characterized in that: In step (1), the alumina raw powder includes pseudo-boehmite powder, the extrusion aid includes one or a combination of sesbania powder, polyacrylamide, graphite and lubricating oil, and the peptizing agent includes one or a combination of nitric acid, hydrochloric acid, acetic acid and citric acid.

6. The preparation method according to claim 4 or 5, characterized in that: Based on the total dry weight of the γ-Al2O3 carrier, the weight contents of the extrusion aid and the peptizing agent are 4-10wt% and 2-5wt% respectively.

7. The preparation method according to claim 4 or 5, characterized in that: The water absorption rate, strength, BET specific surface area and pore volume of the γ-Al2O3 carrier are 90-150%, 8-20N / mm, 290-360m 2 / g and 0.8-1.6mL / g.

8. The preparation method according to claim 4, characterized in that: In step (2), the molar ratio of silicon dioxide to sodium oxide in the sodium silicate is 1.5-3.

0.

9. The preparation method according to claim 4, characterized in that: In step (3), in the co-impregnation solution, the molar ratio of the complexing agent to the auxiliary active metal salt is 1.2-2.2:

1.

10. The preparation method according to claim 4, characterized in that: In step (3), the pH value of the co-impregnation solution is greater than 8.

1.

11. The preparation method according to any one of claims 4, 9-10, characterized in that: In step (3), the complexing agent includes one of ethylenediaminetetraacetic acid, nitrilotriacetic acid, ethylenediamine, cyclohexanediaminetetraacetic acid, citric acid and ethylene glycol.

12. The preparation method according to any one of claims 4, 9-10, characterized in that: In step (3), the auxiliary active metal salt includes one or a combination of nitrates, acetates and carbonates of auxiliary active metals, and the main active metal salt includes one or a combination of ammonium salts and thioammonium salts of main active metals.

13. The preparation method according to claim 4, characterized in that: In step (4), the maximum vulcanization temperature is 280-360°C, the cumulative time of heating and vulcanization is 20-100h, the vulcanization pressure is 1.0-3.0MPa, and the vulcanized oil volume space velocity is 1.0-3.0h -1 , the hydrogen / oil volume ratio is 200:1-500:

1.

14. The preparation method according to claim 4 or 13, characterized in that: In step (4), the sulfurizing agent used in the sulfurization comprises one or a combination of dimethyl disulfide, carbon disulfide, methyl mercaptan, ethyl mercaptan and thioether.

15. Use of the catalytic cracking gasoline selective hydrodesulfurization catalyst according to any one of claims 1 to 3 in the selective hydrodesulfurization of FCC gasoline.

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