A supported sulfide nanosheet catalyst, its synthesis method and application

Abstract

This invention discloses a supported sulfide nanosheet catalyst, its synthesis method, and its application. The catalyst has the chemical formula M'-MS2 / Al2O3, where M' is a promoter metal selected from at least one of Group VIII elements Fe, Co, or Ni, and M is the main metal selected from at least one of Group VIB elements Mo or W. More than 90% of the sulfide MS2 nanosheets are in a monolayer distribution. This catalyst, when used in the hydrodenitrogenation reaction of cracked gasoline, exhibits high activity and low aromatic hydrocarbon hydrogenation loss.

Description

Technical Field

[0001] This invention relates to the field of catalytic technology for hydrodenitrogenation of cracked gasoline, and in particular to a supported sulfide nanosheet catalyst, its synthesis method, and its application. Background Technology

[0002] Cracked gasoline is a key byproduct of naphtha cracking to produce ethylene. Rich in aromatics, it can be used as a high-octane gasoline component or for extracting chemical feedstocks such as benzene, toluene, and xylene after hydrorefining. However, in recent years, the trend towards heavier upstream naphtha feedstocks has led to increasingly complex compositions in cracked gasoline, particularly with a significant increase in nitrogen content. Hydrodenitrogenation (HDN) of cracked gasoline can effectively remove nitrogen compounds, preventing poisoning of downstream aromatic extraction and meeting nitrogen content limits in blended oil components. Therefore, research on the HDN catalytic process of cracked gasoline is crucial for downstream aromatic extraction and blended oil composition.

[0003] In the HDN process of cracked gasoline, the removal of pyridine containing basic nitrogen is the most difficult, making research on pyridine HDN particularly representative. Supported transition metal sulfide catalysts are commonly used industrial hydrorefining catalysts with high hydrogenation activity. Furthermore, compared to noble metal hydrogenation catalysts, sulfide catalysts also have the advantage of low cost. Previous studies have mainly focused on the preparation of Al2O3 supported multilayer sulfides, such as CN106268976A, CN103079697A, and CN102373078A. Previous studies have found that the preparation and synthesis of supported monolayer sulfides lacks controllability, hence there is limited research on their methods. However, due to the unique structure and chemical environment of monolayer sulfides, their hydrogenation activity can be enhanced, thereby promoting the overall HDN reaction performance. Therefore, developing monolayer sulfide nanosheets and studying their HDN catalytic performance is extremely meaningful. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a supported sulfide nanosheet catalyst, its synthesis method, and its applications. In this catalyst, the vast majority (over 90%) of the sulfide nanosheets are monolayers. When used in the hydrodenitrogenation reaction of cracked gasoline, it exhibits high activity, low aromatic hydrocarbon hydrogenation loss, and a relatively simple and controllable preparation process.

[0005] The first aspect of the present invention provides a supported sulfide nanosheet catalyst, wherein the catalyst has the chemical formula M'-MS2 / Al2O3, wherein M' is a promoter metal selected from at least one of Group VIII elements Fe, Co or Ni, and M is the main metal selected from at least one of Group VIB elements Mo or W; and more than 90% of the sulfide (MS2) nanosheets are in a monolayer distribution state.

[0006] Furthermore, preferably, 90% to 98% of the sulfide (MS2) nanosheets are in a monolayer distribution.

[0007] Furthermore, in the catalyst, based on the weight of the catalyst, the Al2O3 content is 70% to 80%, the M content (calculated as oxides) is 12% to 20%, and the M' content (calculated as oxides) is 8% to 10%.

[0008] Furthermore, the length of the sulfide (MS2) nanosheets is 2.0–20.0 nm, preferably 2.0–10.0 nm, and even more preferably 2.0–5.0 nm.

[0009] Furthermore, the specific surface area of ​​Al2O3 is 250–400 m². 2 / g, preferably 300-375m 2 / g; the amount of Brønsted acid on the Al2O3 surface is 5-25 μmol / g, preferably 10-20 μmol / g, and more preferably 12.5-15.5 μmol / g.

[0010] A second aspect of this invention provides a method for preparing the above-mentioned supported sulfide nanosheet catalyst, comprising:

[0011] (1) Al2O3 is obtained by hydrothermal treatment, calcination and molding of boehmite;

[0012] (2) Metals M and M' were loaded onto Al2O3, aged, and calcined to obtain catalyst precursors;

[0013] (3) The catalyst precursor is sulfided and reduced to obtain the catalyst.

[0014] Furthermore, in step (1), the average particle size of the pseudoboehmite particles is 100-400 mesh, preferably 150-300 mesh.

[0015] Furthermore, in step (1), the pseudoboehmite is subjected to conventional treatments such as drying, cooling, and grinding before hydrothermal treatment.

[0016] Further, in step (1), the hydrothermal treatment is carried out under high-temperature sealed dynamic stirring conditions. The hydrothermal treatment conditions are: temperature 150-250℃, pH value 1.5-10.5, time 4-24h, stirring speed 200-800r / min, and heating rate to the hydrothermal treatment temperature 0.5-2.0℃ / min; preferably, temperature 150-200℃, pH value 4.0-9.0, time 4-12h; more preferably, temperature 180-200℃, pH value 7.5-9.0, time 6-12h.

[0017] Further, in step (1), after the hydrothermal treatment, the material undergoes conventional treatment of separation, washing, and drying. The washing is selected from distilled water, ethanol, or isopropanol, preferably ethanol; the separation, for example, is performed by suction filtration, using either a Buchner funnel or a sintered glass funnel, preferably a sintered glass funnel.

[0018] Further, in step (1), the calcination is carried out under high-temperature dynamic conditions. The calcination conditions are: temperature of 500-750℃, preferably 500-650℃, time of 3-8h, and heating rate to the calcination temperature of 0.5-4.0℃ / min, preferably 1.0-4.0℃ / min.

[0019] Further, in step (1), the forming can be done by extrusion or pressing, preferably extrusion; the shape is either cylindrical or clover-shaped, preferably cylindrical; the diameter and length of the cylindrical shape are 1-5 mm and 2-6 mm, respectively, preferably 2-4 mm and 3-5 mm.

[0020] Furthermore, in step (2), the metal load is impregnated by equal volume.

[0021] Further, in step (2), metal M' is selected from at least one of Group VIII elements Fe, Co, or Ni, and metal M is selected from at least one of Group VIB elements Mo or W. The main metal (M) salt is ammonium molybdate tetrahydrate (NH4)6Mo7O 24 • 4H2O or ammonium tungstate hexahydrate (NH4)6W7O 24 At least one of ·6H2O, and the auxiliary metal (M') salt is selected from at least one of Fe(NO3)3·9H2O, Co(NO3)2·6H2O and Ni(NO3)2·6H2O.

[0022] Further, in step (2), when the main metal M is Mo, the molar ratio of molybdenum salt to Al2O3 is 1:(50-80); when the main metal M is W, the molar ratio of tungsten salt to Al2O3 is 1:(100-200). The molar ratio of auxiliary metal salt to Al2O3 is 1:(20-50).

[0023] Furthermore, in step (2), the aging temperature is 20-50°C, preferably 30-40°C, and the aging time is 4-48h, preferably 16-24h.

[0024] Further, in step (2), after aging, the product undergoes a separation and drying process. The drying conditions are: heating at 0.5–2 °C / min to 100–150 °C for 8–24 hours.

[0025] Further, in step (2), the calcination conditions are: calcination temperature of 450-550℃, calcination time of 3-8h, and heating rate of 0.5-4℃ / min to calcination temperature.

[0026] Furthermore, in step (4), the sulfiding oil used for sulfidation is prepared from dimethyl disulfide (DMDS) and cyclohexane, with a sulfur content of 400 to 5000 ppm.

[0027] Further, in step (4), the sulfidation / reduction pressure is 2.6–3.0 MPa, the volume ratio of hydrogen to catalyst precursor is (10–100):1, and the volume hourly space velocity of the sulfidation oil is 3.0–5.0 h⁻¹. 1 The vulcanization time is 20 to 40 hours.

[0028] Further, in step (4), the sulfidation process is as follows: the temperature is raised to 150-180°C at a heating rate of 20-50°C / h, the sulfidation oil is introduced, and the temperature is raised to 280-320°C at a heating rate of 20-50°C / h. After maintaining the temperature for 20-40 hours, the temperature is naturally lowered to 150-180°C and the sulfidation oil is stopped. After cooling to room temperature, the catalyst is stored in an inert atmosphere or organic solvent for later use.

[0029] Furthermore, the inert atmosphere may be Ar and / or He, preferably Ar. The organic solvent may be at least one selected from cyclohexane, benzene, toluene, and xylene, preferably cyclohexane.

[0030] The third aspect of this invention provides the application of the above-mentioned supported sulfide nanosheet catalyst in the hydrodenitrogenation reaction of cracked gasoline.

[0031] Furthermore, the reaction conditions for the hydrodenitrification reaction are: a reaction temperature of 220–400 °C, a reaction pressure of 2.5–4.0 MPa, and a volume hourly space velocity of 0.5–4.0 h⁻¹. 1 The hydrogen / oil volume ratio is 500–700.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. This invention provides a supported sulfide nanosheet catalyst with the chemical formula M'-MS2 / Al2O3, wherein the sulfide (MS2) nanosheets are distributed in a monolayer state with a sheet length of 2-20 nm. At the same time, the amount of Brønsted acid on the surface of the Al2O3 support in the catalyst is controlled at 5-25 μmol / g. It is used for the hydrodenitrogenation reaction of cracked gasoline and has the characteristics of high activity and low loss of aromatic hydrogenation.

[0034] 2. This invention regulates the number of hydroxyl groups on the carrier surface by controlling the hydrothermal temperature, time, and pH value of the carrier, thereby affecting the interaction strength between the carrier and the active component, forming a monolayer sulfide structure, and ultimately affecting the amount of Brønsted acid on the surface of the carrier and catalyst. Compared with the multilayer transition metal sulfide sheet stacking structure, the utilization rate of active centers is high, and the entire preparation process is simple, easy, controllable, and low in cost. Attached Figure Description

[0035] Figure 1 The XRD patterns of the catalysts in Examples 5 and 11 are shown below.

[0036] Figure 2 Here is an HRTEM image of the catalyst in Example 11;

[0037] Figure 3 The XRD patterns of the carriers used in Examples 2, 4, and 5 are shown.

[0038] Figure 4 The infrared spectra of pyridine for the carriers used in Examples 2, 4 and 5 are shown. Detailed Implementation

[0039] The present invention will now be described in detail with reference to specific embodiments. These embodiments are for illustrative purposes only and do not constitute any limitation thereof. The invention has been described with reference to exemplary embodiments, but it should be understood that the terms used are descriptive and explanatory, not limiting. Modifications and revisions can be made to the invention within the scope of the claims as specified herein, without departing from the scope and spirit of the invention. Although the invention described herein relates to specific methods, materials, and embodiments, it does not imply that the invention is limited to the specific examples disclosed herein; on the contrary, the invention can be extended to all other methods and applications with the same function.

[0040] In the context of this specification, X-ray diffraction (XRD) analysis of the catalyst was performed on a Rigaku D / max-2200PC X-ray diffractometer, using Cu Kα radiation, tube voltage 40 kV, tube current 30 mA, scan rate 10° / min, and scan range 10°–80°.

[0041] In the context of this specification, the microstructure and particle size of the catalyst were observed using high-resolution transmission electron microscopy (HRTEM). The FEI Tecnai G... 2HRTEM analysis was performed using an F20 S-TWIN transmission electron microscope system. This system is equipped with a field emission gun with an accelerating voltage of 200 kV and a point resolution of 0.24 nm. Using Nano Measurer software, the dimensions of more than 300 nanosheet particles selected from a random field of view were observed and measured, and the average length of the nanosheets was determined.

[0042] In the context of this specification, the proportion of monolayer distributed sulfide nanosheets is obtained by statistically analyzing the proportion of monolayer distributed MS2 in the HRTEM. The monolayer distribution proportion = n(monolayer MS2) / n(all MS2), where n(monolayer MS2) and n(all MS2) are the number of monolayer MS2 sheets and the number of all MS2 within the field of view, respectively, and the number of counted items is no less than 300.

[0043] In the context of this specification, pyridine infrared (Py-FTIR) analysis was performed using a Nicolet 5700 Fourier transform infrared spectrometer. The scan range was 1300–4000 cm⁻¹. 1 The number of scans was 32, and the resolution was 4cm- 1 Take approximately 15 mg of sample, compress it into tablets, demold it to obtain a self-supporting tablet, place it in a reaction chamber, vacuum at 400℃ for 2 h, cool it to 50℃ to remove the background, open the valve of the pyridine adsorption chamber until the catalyst pyridine adsorption is saturated, then program the temperature to 300℃, vacuum for 0.5 h, finally take the spectrum and remove the background. The specific calculation formula is shown in formula (1): where the unit of Brønsted acid is μmol / g; A (Brønsted acid) is 1540 cm⁻¹. 1 The integral peak area of ​​the characteristic peak; r is the radius of the self-supporting sample piece in cm; w is the mass of the sample piece in mg.

[0044]

[0045] In the context of this specification,

[0046]

Example 1

[0047] 0.55 g of citric acid was added to 19.0 g of distilled water to prepare an acidic solution with a pH of 1.5. 10.0 g of boehmite (AlOOH·nH2O) was dried, cooled, and ground to 200 mesh. The solution was transferred to a 500 mL hydrothermal crystallization reactor, and the citric acid solution was added. The mixture was stirred thoroughly at 600 r / min, and then heated to 180 °C at a rate of 0.5 °C / min, maintaining the hydrothermal environment for 12 h. After the reactor cooled, the resulting solid was washed three times with ethanol, filtered through a sintered glass funnel, and then heated to 550 °C at a rate of 1.0 °C / min under dynamic air conditions, maintaining the temperature for 6 h. The resulting solid powder was extruded into cylindrical strips with a diameter and height of 3 mm and 5 mm, respectively, denoted as carrier Al2O3-1.5 (in this example, Al2O3-x, where x represents the pH value of the hydrothermal environment).

[0048] The saturated water absorption rate of the Al2O3-1.5 support was measured. 0.232 g of ammonium molybdate tetrahydrate was dissolved in distilled water weighed according to the saturated water absorption rate, and an equal volume was impregnated onto 1.0 g of Al2O3-1.5 support. After aging at 30 °C for 12 h, it was dried at 120 °C for 12 h under dynamic air. The resulting solid was heated to 500 °C at a rate of 2 °C / min and held for 6 h to obtain the catalyst precursor. 4.0 g of the above catalyst precursor was loaded into a sulfidation reactor, and sulfidation oil with a sulfur content of 3000 ppm, prepared from DMDS and cyclohexane, was introduced. Hydrogen gas was introduced at a pressure of 2.6 MPa, with a hydrogen-to-catalyst volume ratio of 100:1. The catalyst bed was heated to 150 °C at a heating rate of 30 °C / h, and sulfidation oil was introduced at a space velocity of 4.0 h⁻¹. -1 The catalyst bed was heated to 320℃ at a heating rate of 30℃ / h and held for 32h. Then it was allowed to cool down to 150℃ and the sulfided oil was stopped. After cooling to room temperature, it was stored in cyclohexane. The resulting catalyst SS1 was designated as MS2 / Al2O3-1.5.

[0049]

Example 2

[0050] The catalyst was prepared in the same way as in Example 1, except that the amount of distilled water required to dissolve the citric acid was changed from 19.0g to 40.0g; the final catalyst SS2 was obtained.

[0051]

Example 3

[0052] The catalyst was prepared using the same method as in Example 1, except that 0.55g of citric acid was replaced with 0.55g of acetic acid; the final catalyst was SS3.

[0053]

Example 4

[0054] The catalyst preparation method is the same as in [Example 1], except that instead of adding 0.55g of citric acid to 19.0g of distilled water, citric acid is not added, and the catalyst SS4 is finally obtained.

[0055]

Example 5

[0056] The catalyst preparation method is the same as in [Example 1], except that instead of adding 0.55g of citric acid to 19.0g of distilled water, 1.58g of ammonium bicarbonate is added to 200g of distilled water, and the catalyst SS5 is finally obtained.

[0057]

Example 6

[0058] The catalyst preparation method is the same as in [Example 1], except that instead of adding 0.55g of citric acid to 19.0g of distilled water, 1.92g of ammonium carbonate is added to 200g of distilled water, and the catalyst SS6 is finally obtained.

[0059]

Example 7

[0060] The catalyst preparation method is the same as in [Example 5], except that the calcination conditions of the support were changed from heating to 550°C at a rate of 1.0°C / min to heating to 700°C at a rate of 0.5°C / min, and finally catalyst SS7 was obtained.

[0061]

Example 8

[0062] The catalyst preparation method is the same as in [Example 5], except that the main metal impregnation solution is changed from 0.232g ammonium molybdate tetrahydrate to 0.354g ammonium tungstate hexahydrate, and finally catalyst SS8 is obtained.

[0063]

Example 9

[0064] The catalyst was prepared using the same method as in [Example 5], except that 0.11 g of Fe(NO3)3·9H2O auxiliary metal salt was added to the main metal impregnation solution, ultimately yielding catalyst SS9. In catalyst SS9, 93% of the MoS2 nanosheets were in a monolayer distribution.

[0065]

Example 10

[0066] The catalyst was prepared using the same method as in [Example 5], except that 0.08 g of Co(NO3)3·6H2O auxiliary metal salt was added to the main metal impregnation solution, ultimately yielding catalyst SS10. In catalyst SS10, 95% of the MoS2 nanosheets were in a monolayer distribution.

[0067]

Example 11

[0068] The catalyst preparation method is the same as in [Example 5], except that 0.08g of Ni(NO3)3·6H2O auxiliary metal salt is added to the main metal impregnation solution to finally obtain catalyst SS11. Figure 2The image shows an HRTEM image of catalyst SS11. Calculations show that 97% of the MoS2 nanosheets are in a monolayer distribution.

[0069]

Example 12

[0070] The catalyst preparation method is the same as in [Example 5], except that the sulfidation temperature is changed from 320℃ to 300℃, and the catalyst SS12 is finally obtained.

[0071]

Example 13

[0072] The catalyst preparation method is the same as in [Example 8], except that 0.08g of Ni(NO3)3·6H2O auxiliary metal salt is added to the main metal impregnation solution to finally obtain catalyst SS13.

[0073]

Example 14

[0074] The catalyst preparation method is the same as in [Example 1], except that instead of adding 0.55g of citric acid to 19.0g of distilled water, 6.36g of sodium carbonate is added to 200g of distilled water, and the catalyst SS14 is finally obtained.

[0075]

Example 15

[0076] The catalyst preparation method is the same as in [Example 1], except that instead of adding 0.55g of citric acid to 19.0g of distilled water, 1.70g of sodium bicarbonate is added to 200g of distilled water, and the catalyst SS15 is finally obtained.

[0077]

Example 16

[0078] The catalyst preparation method is the same as in [Example 5], except that the hydrothermal treatment temperature is adjusted to 150°C, and the final catalyst SS16 is obtained.

[0079]

Example 17

[0080] The catalyst preparation method is the same as in [Example 5], except that the hydrothermal treatment time is adjusted to 24h, and the final catalyst SS17 is obtained.

[0081]

Example 18

[0082] The catalyst preparation method is the same as in [Example 5], except that the hydrothermal treatment temperature is adjusted to 220°C, and the catalyst SS18 is finally obtained.

[0083]

Comparative Example 1

[0084] At room temperature (25℃), 0.15g of ammonium tungstate tetrahydrate ((NH4)6W7O) was added. 24• 4H2O) was dissolved in 5 mL of H2O, stirred thoroughly, and then an equal volume of 5.0 g of untreated Al2O3 support (the pseudoboehmite from Example 1 was dried, cooled, ground to 200 mesh, and calcined at 550°C for 6 h) was impregnated and loaded. After the same subsequent aging, drying, calcination, and sulfidation treatment steps as in Example 1, the resulting catalyst was designated BJ1. HRTEM images show that the Al2O3 support was untreated, and the loaded MoS2 nanosheets were in a multilayered stacked state.

[0085] [Comparative Example 2]

[0086] At room temperature (25℃), 1.17g of ammonium molybdate tetrahydrate ((NH4)6Mo7O) was added. 24 • 4H2O) was dissolved in 5 mL of H2O, stirred thoroughly, and then an equal volume of 5.0 g of untreated Al2O3 support (the pseudoboehmite from Example 1 was dried, cooled, ground to 200 mesh, and calcined at 550°C for 6 h) was impregnated and loaded. After the same subsequent aging, drying, calcination, and sulfidation treatment steps as in Example 1, catalyst BJ2 ​​was obtained. HRTEM images show that the Al2O3 support was untreated, and the loaded MoS2 nanosheets were in a multilayered stacked state.

[0087]

Application Example

[0088] 1.0 g of the catalyst from Examples 1-18 and Comparative Examples 1-2 were weighed and charged into a fixed-bed reactor. The inlet temperature was 240°C, the pressure was 2.5 MPa, the hydrogen / oil volume ratio was 600:1, and the fresh oil volume hourly space velocity was 2.0 h⁻¹. -1 Under the reaction conditions, a simulated nitrogen- and sulfur-containing cracked gasoline component (a mixed solution of pyridine and BTX at 30 ppmw, with a benzene:toluene:xylene molar ratio of 30:40:30 in BTX) underwent HDN reaction. The denitrogenation and aromatic hydrogenation saturation rates during the reaction were analyzed. The results are shown in Table 2.

[0089] Table 1. Physicochemical properties of catalyst supports (Al2O3) in Examples and Comparative Examples

[0090] catalyst carrier <![CDATA[Specific surface area / m 2 / g]]> B acid content (μmol / g) SS1 <![CDATA[Al2O3-1.5]]> 252.6 5.7 SS2 <![CDATA[Al2O3-2.5]]> 285.6 7.4 SS3 <![CDATA[Al2O3-3.5]]> 305.8 8.6 SS4 <![CDATA[Al2O3-7.0]]> 322.6 10.7 SS5 <![CDATA[Al2O3-8.2]]> 350.0 15.1 SS6 <![CDATA[Al2O3-10.5]]> 330.7 22.6 SS14 <![CDATA[Al2O3-7.8]]> 331.3 12.8 SS15 <![CDATA[Al2O3-8.7]]> 342.2 13.8 SS16 <![CDATA[Al2O3-8.2]]> 297.4 18.2 SS17 <![CDATA[Al2O3-8.2]]> 362.5 9.9 SS18 <![CDATA[Al2O3-8.2]]> 367.7 8.6 BJ1 / BJ2 <![CDATA[Al2O3]]> 342.1 10.5

[0091] Table 2. Catalyst composition and catalytic performance evaluation results for each example.

[0092]

[0093]

[0094] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A supported sulfide nanosheet catalyst, wherein the catalyst has the chemical formula M'-MS2 / Al2O3, wherein, M' is an auxiliary metal selected from at least one of group VIII elements Fe, Co or Ni, M is a main metal selected from at least one of group VIB elements Mo or W; more than 90% of the sulfide nanosheets are in a single-layer distribution state; the specific surface area of Al2O3 is 250-400 m 2 / g, the B acid amount of Al2O3 surface is 5-25 µmol / g; the length of the sulfide nanosheet layer is 2.0-10.0 nm.

2. The catalyst according to claim 1, characterized in that: In the catalyst, based on the weight of the catalyst, the Al2O3 content is 70%~80%, the M content (calculated as oxides) is 12%~20%, and the M' content (calculated as oxides) is 8%~10%.

3. The catalyst according to claim 1, characterized in that: The sulfide nanosheets have a sheet length of 2.0~5.0 nm.

4. The catalyst according to claim 1, characterized in that: The specific surface area of ​​Al2O3 is 300~375 m². 2 / g; the amount of Brønsted acid on the Al2O3 surface is 10~20 µmol / g.

5. The catalyst according to claim 4, characterized in that: The surface Brønsted acid content of Al2O3 is 12.5~15.5 µmol / g.

6. A method for preparing the catalyst according to any one of claims 1-5, comprising: (1) Al2O3 is obtained by hydrothermal treatment, calcination and molding of boehmite; (2) Metals M and M' were loaded onto Al2O3, aged, and calcined to obtain the catalyst precursor; (3) The catalyst precursor is sulfided to obtain the catalyst; In step (1), the hydrothermal treatment conditions are: temperature 150~200 ℃, pH value 4.0~9.0, and time 4~12 h; In step (3), during the sulfidation process, the volume ratio of hydrogen to catalyst precursor is (10~100):1, the sulfidation temperature is 280~320 ℃, and the sulfidation time is 20~40 h.

7. The preparation method according to claim 6, characterized in that: In step (1), the average particle size of the pseudoboehmite particles is 100~400 mesh.

8. The preparation method according to claim 7, characterized in that: In step (1), the average particle size of the pseudoboehmite particles is 150~300 mesh.

9. The preparation method according to claim 6, characterized in that: In step (1), the hydrothermal treatment conditions are: temperature 180~200 ℃, pH value 7.5~9.0, and time 6~12 h.

10. The preparation method according to claim 6, characterized in that: In step (1), the calcination conditions are: temperature of 500~750 ℃, time of 3~8 h, and heating rate of 0.5~4.0 ℃ / min to calcination temperature; And / or, in step (2), the aging temperature is 20~50 ℃ and the aging time is 4~48 h; And / or, in step (2), after aging, a separation and drying process is performed, wherein the drying conditions are: heating to 100~150 ℃ at 0.5~2 ℃ / min and drying for 8~24 h; And / or, in step (2), the calcination conditions are: calcination temperature of 450~550 ℃, calcination time of 3~8 h, and heating rate of 0.5~4 ℃ / min to calcination temperature.

11. The preparation method according to claim 10, characterized in that: In step (2), the aging temperature is 30~40℃ and the aging time is 16~24 h.

12. The preparation method according to claim 6, characterized in that: In step (2), the main metal salt is ammonium molybdate tetrahydrate (NH4)6Mo7O 24 • 4H2O or ammonium tungstate hexahydrate (NH4)6W7O 24 At least one of ·6H2O, and the auxiliary metal salt is selected from at least one of Fe(NO3)3·9H2O, Co(NO3)2·6H2O and Ni(NO3)2·6H2O.

13. The preparation method according to claim 6, characterized in that: The sulfiding oil used for sulfidation is formulated from dimethyl disulfide and cyclohexane, with a sulfur content of 400~5000 ppm by mass. And / or, the vulcanization pressure is 2.6~3.0 MPa, and the vulcanizing oil volume hourly space velocity is 3.0~5.0 h⁻¹. -1 .

14. The use of the catalyst according to any one of claims 1-5 in the hydrodenitrogenation reaction of cracked gasoline.

15. The application according to claim 14, characterized in that: The reaction conditions for the hydrodenitrification reaction are as follows: reaction temperature 220–400 °C, reaction pressure 2.5–4.0 MPa, and volume hourly space velocity (VHSV) 0.5–4.0 h⁻¹. -1 The hydrogen / oil volume ratio is 500~700.

Images