A process for the preparation of a catalytic cracking gasoline hydro-upgrading catalyst

Abstract

This invention relates to a method for preparing a catalyst for hydrotreating catalytic cracking gasoline, comprising the following steps: (1) mixing alumina powder and acidic molecular sieve, extruding, drying, and calcining to obtain a catalyst support; (2) preparing a co-impregnation solution containing a complexing agent and an active metal CoMo or NiMo, and adjusting the pH value of the co-impregnation solution to be greater than 8.1, preferably greater than 8.2, wherein the molar ratio of the complexing agent to Co or Ni in the co-impregnation solution is 1.2-2.2, preferably 1.5-1.7; (3) impregnating the catalyst support with an equal volume of the co-impregnation solution, and after aging and drying at room temperature, obtaining a one-impregnation, non-calcined semi-finished product; (4) sulfiding the one-impregnation, non-calcined semi-finished product in step (3) to obtain a hydrotreating catalyst. The obtained catalyst exhibits excellent comprehensive performance in deep desulfurization, significant reduction of olefins, and preservation of octane number for FCC gasoline.

Description

Technical Field

[0001] This invention belongs to the field of clean gasoline catalytic cracking technology, specifically relating to a method for preparing a catalyst for hydrotreating catalytic cracking gasoline. Background Technology

[0002] To reduce the sulfur and olefin content in catalytic cracking (FCC) gasoline while maintaining its octane number, the Petrochemical Research Institute, in collaboration with China University of Petroleum (Beijing) and Fuzhou University, jointly developed the FCC gasoline hydrotreating GARDES series of technologies. This technology has been successfully applied to nine FCC gasoline hydrotreating units at PetroChina. However, its performance needs further improvement to meet the National VIB standard and even the Beijing VIB scheme (draft for comments) (which requires olefin content in gasoline to be reduced to ≤15v% and ≤10-12v%, respectively).

[0003] Currently, the preparation of FCC gasoline hydro-upgrading catalysts supporting this technology adopts the traditional preparation process of "two-step impregnation - two-step calcination". For example, Lin et al. (Catalysis Today, 2007, 125:185–191) reported a preparation method for FCC gasoline hydro-upgrading catalysts. First, 30 wt.% of SB powder and 70 wt.% of H-ZSM-5 molecular sieve were kneaded and extruded into pellets; then dried overnight at 110 °C and calcined at 520 °C for 5 h to obtain the catalyst support; finally, ammonium molybdate and nickel nitrate were impregnated onto this support in two steps. After each step of impregnation, it was necessary to dry at 120 °C for 5 h and calcine at 480 °C for 4 h to finally obtain the NiMo / HZSM-5--γAl2O3 catalytic cracking gasoline hydro-upgrading catalyst. CN200610083284.0 provides a ZSM-5 / SAPO-11 composite zeolite and a catalytic cracking gasoline hydro-upgrading catalyst and its preparation method. Using the equal-volume impregnation method, ammonium molybdate was impregnated onto the ZSM-5 / SAPO-11 composite zeolite support, and an impregnated product was obtained after drying and calcination treatments. Finally, using the equal-volume impregnation method again, nickel nitrate was impregnated onto this impregnated product, and after further drying and calcination treatments, the catalytic cracking gasoline hydro-upgrading catalyst was obtained. CN200910080324.X invented a catalyst for catalytic cracking gasoline hydro-upgrading and its preparation method. The present invention uses a modified ZSM-5 molecular sieve as the support, and the recommended best way to load the active metal is: first load molybdenum and then load nickel, with step-by-step calcination. Specifically, it can be: the modified ZSM-5 molecular sieve support was impregnated into an ammonium molybdate aqueous solution for 6 - 12 hours, and after drying and calcination at 450 - 520 °C for 2 - 6 hours, a catalyst intermediate containing molybdenum oxide was obtained; this catalyst intermediate was impregnated into a nickel nitrate aqueous solution, dried, and calcined at 450 - 520 °C for 2 - hours to obtain the catalyst. From the above research and invention patents, it can be seen that the existing preparation process of FCC gasoline hydro-upgrading catalysts has problems such as many steps, nitrogen oxide emissions during the calcination process, and strong interaction (low activity) between the active metal of the catalyst and its support.

[0004] To this end, Jin et al. (Petroleum Refining and Chemical Engineering, 2020, 51(8):62-69) prepared a series of CoMo supported catalysts with complexing agents citric acid, nitric acid, ethylenediaminetetraacetic acid, and cyclohexanediaminetetraacetic acid as the support using ZSM-5-Al2O3 composite as the support, and investigated the effect of complexing agents on the selectivity of CoMo catalyst hydrodesulfurization. The results showed that the complexing agents added during the catalyst preparation process preferentially complexed with Co and Al in the support. This complexing effect increased the number of active centers, the number of MoS2 lamellar stacking layers, and the length of MoS2 lamellars, but the increase in desulfurization activity of the catalyst modified by the complexing agent was greater than the increase in olefin saturation activity. However, this study reported a selective hydrodesulfurization design concept that protects olefins from conversion, without fine-tuning the morphology of the Co-Mo-S active phase, and did not find that the complexing agent significantly enhanced the medium-strong acid content of the catalyst. Therefore, it could not simultaneously solve the major technical problem of deep desulfurization of catalytic gasoline, significant reduction of olefins, and maintenance of octane number. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing a catalyst for hydrotreating catalytic cracking gasoline, so as to solve the major technical problem that the preparation process of the catalyst for hydrotreating catalytic cracking gasoline is complicated and cannot simultaneously solve the major technical problems of deep desulfurization of catalytic gasoline, significant reduction of olefins and maintenance of octane number.

[0006] To achieve the above objectives, the present invention provides a method for preparing a catalyst for catalytic cracking gasoline hydrotreating, comprising the following steps:

[0007] (1) Alumina powder and acidic molecular sieve are mixed, extruded, dried and calcined to obtain a catalyst support;

[0008] (2) Prepare a co-impregnation solution containing a complexing agent and an active metal CoMo or NiMo, and adjust the pH value of the co-impregnation solution to be greater than 8.1, preferably greater than 8.2, and the atomic molar ratio of the complexing agent to Co or Ni in the co-impregnation solution is 1.2-2.2, preferably 1.5-1.7;

[0009] (3) The co-impregnation liquid is impregnated onto the catalyst support in equal volume, and after aging and drying at room temperature, a single-impregnation non-calcination semi-finished product is obtained;

[0010] (4) The sulfidation step (3) yields a hydrogenation-modified catalyst by dipping and calcining the semi-finished product.

[0011] In step (3) above, the co-impregnation liquid is impregnated onto the catalyst support in an equal volume at one time.

[0012] The preparation method of the catalytic cracking gasoline hydrotreating catalyst of the present invention uses alumina powder, which is boehmite powder and / or aluminum hydroxide powder, preferably boehmite powder. The boehmite powder of the present invention can be ordinary low-purity boehmite powder or high-purity boehmite powder, i.e., SB powder.

[0013] The method for preparing the catalytic cracking gasoline hydrotreating catalyst of the present invention wherein the acidic molecular sieve is one or more of H-ZSM-5, SAPO-11, Hβ and HMOR, preferably H-ZSM-5 and / or SAPO-11.

[0014] The preparation method of the catalytic cracking gasoline hydrotreating catalyst of the present invention, wherein the complexing agent is one or more of ethylenediaminetetraacetic acid, nitric acid, ethylenediamine, cyclohexanediaminetetraacetic acid, citric acid and ethylene glycol, preferably one or more of ethylenediaminetetraacetic acid, nitric acid, ethylenediamine and cyclohexanediaminetetraacetic acid.

[0015] In the preparation method of the catalytic cracking gasoline hydrotreating catalyst of the present invention, in step (2), the co-impregnation solution is prepared at a temperature of 10-90℃, preferably 10-30℃; the impregnation solution is prepared for 0.2-4h, preferably 0.5-2h.

[0016] The preparation method of the catalytic cracking gasoline hydrotreating catalyst of the present invention comprises the following: the active metal Mo source in the co-impregnation solution is one or more of ammonium heptamolybdate, ammonium tetramolybdate, and ammonium tetrathiomolybdate, preferably ammonium heptamolybdate and / or ammonium tetrathiomolybdate; the active metal Co source in the co-impregnation solution is one or more of cobalt nitrate, cobalt acetate, and cobalt carbonate, preferably cobalt nitrate and / or cobalt acetate; the active metal Ni source in the co-impregnation solution is one or more of nickel nitrate, nickel acetate, and nickel carbonate, preferably nickel nitrate and / or nickel acetate.

[0017] In the preparation method of the catalytic cracking gasoline hydrotreating catalyst of the present invention, in step (3), the drying temperature is 100-140℃, preferably 110-130℃; the drying time is 2-8h, preferably 4-6h.

[0018] The preparation method of the catalytic cracking gasoline hydrotreating catalyst of the present invention, wherein the sulfidation step (4) is carried out in a fixed-bed reactor, and sulfidation is performed using sulfided oil containing a sulfiding agent. The sulfiding agent is one or more of dimethyl disulfide, carbon disulfide, methanethiol, ethanethiol, dimethyl sulfide, and sulfides, preferably dimethyl disulfide and / or carbon disulfide; the sulfidation temperature is 270-350℃, preferably 280-300℃; the sulfidation time is 20-100h, preferably 25-50h; the sulfidation pressure is 1.0-3.0MPa, preferably 1.5-2.5MPa; and the sulfided oil volume hourly space velocity is 1.0-3.0h. -1Preferably 1.0-2.0h -1 The hydrogen / oil volume ratio is 200:1-500:1, preferably 250:1-350:1.

[0019] The preparation method of the catalytic cracking gasoline hydrotreating catalyst of the present invention, when the active metal is CoMo, the hydrotreating catalyst, based on oxides, comprises 0.2-20.0 wt% Co2O3, 2.0-20.0 wt% MoO3, preferably 0.5-15.0 wt% Co2O3, 4.0-14.0 wt% MoO3, with an atomic molar ratio of S / (Co+Mo) of 1.0-3.0, preferably 1.6-2.5; when the active metal is NiMo, the hydrotreating catalyst, based on oxides, comprises 0.2-20.0 wt% NiO, 2.0-20.0 wt% MoO3, preferably 0.5-15.0 wt% NiO, 4.0-14.0 wt% MoO3, with an atomic molar ratio of S / (Ni+Mo) of 1.0-3.0, preferably 1.6-2.5; the Mo in the hydrotreating catalyst... 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio of the acid content to the total acid content is 60-100%, preferably 65-100%; the total acid content is 630-1500 μmol / g, preferably 640-1000 μmol / g; the medium-strong acid content is 460-1000 μmol / g, preferably 480-800 μmol / g; the average length of the MoS2 wafer is 3.5-4.5, preferably 3.8-4.2; and the average number of stacked layers of the MoS2 wafer is 3.0-4.0, preferably 3.4-3.8.

[0020] Beneficial effects of this invention:

[0021] This invention achieves a stable co-impregnation solution of Co(Ni) and Mo by adjusting the molar ratio of the complexing agent / Co(Ni) and the pH value of the impregnation solution, without the need for calcination of the catalyst precursor. Therefore, the catalyst preparation process is simple and there is no nitrogen oxide emission.

[0022] The molar ratio of complexing agent to Co(Ni) and the pH value of the impregnation solution play important roles in the morphology and acidity regulation of the Co(Ni)-Mo-S active phase of the catalyst. Only with a suitable molar ratio of complexing agent to Co(Ni) and pH value of the impregnation solution can the catalyst exert its beneficial effects: (1) ensuring the stability and clarity of the impregnation solution; (2) enabling the complexing agent to interact with the Al on the support surface. 3+ Preferential interactions reduce the interaction between molybdenum species and Al on the support surface. 3+The interaction between the molybdenum species and the support surface Al makes the molybdenum species exist as polymolybdates that are more easily sulfidated, which is conducive to the formation of MoS2 lamellar crystals with lower dispersion (longer average length and higher average number of stacked layers); (3) through the interaction between the anions of the complexing agent salt and the Al on the support surface 3+ Preferential interactions reduce the interaction between Co(Ni) species and Al on the support surface. 3+ The interaction between the Co(Ni) species and the Co(Ni) species further complexes with the Co(Ni) species, increasing the sulfidation temperature of the Co(Ni) species and causing the Co(Ni) species to generate more highly active Co(Ni)-Mo-S type II active phases at the edge of the MoS2 lamellae; (4) through the interaction between the anions of the complexing agent salt and the Al on the support surface 3+ The preferential interaction protects the medium-to-strong acidic sites on the carrier surface from being covered by metal, so that more acidic sites can be released after sulfidation (complex decomposition).

[0023] Conversely, the following negative effects will occur: (1) A low molar ratio of complexing agent to Co(Ni) is not conducive to obtaining a catalyst with a high activity of Co(Ni)-Mo-S type II active phase and more acidic sites, and it cannot effectively protect the acidic sites on the support surface (from being covered by metal); (2) A high molar ratio of complexing agent to Co(Ni) will cause the complexing agent to form a complex with the molybdenum species, which is not conducive to its sulfidation into MoS2; (3) A low pH value of the impregnation solution is not conducive to the complexing agent forming a stable complex solution with Co(Ni).

[0024] By adjusting the molar ratio of complexing agent / Co(Ni) (1.2-2.2) and the pH value of the impregnation solution (greater than 8.1), the morphology of the Co(Ni)-Mo-S active phase and the amount of medium-strong acid in the catalyst were simultaneously controlled. As a result, the catalyst obtained has a unique Co(Ni)-Mo-S active phase morphology and a large amount of medium-strong acid.

[0025] Using FCC gasoline feedstock with a sulfur content of approximately 240 mg / kg and an olefin content of approximately 24 vol%, the reaction was carried out at a reaction temperature of 360℃, a reaction pressure of 2.0 MPa, and a volume hourly space velocity of 2.0 h⁻¹. -1 Under the condition of a hydrogen-to-oil volume ratio of 300:1, the catalyst of the present invention has a higher desulfurization rate and olefin reduction in hydrogenated gasoline products compared with the FCC gasoline hydrotreating catalyst prepared by the "two-step impregnation-two-step roasting" process, but the octane number loss is basically the same.

[0026] It can be seen that by adjusting the molar ratio of complexing agent / Co(Ni) and the pH value of impregnation solution, this invention simplifies the preparation process of FCC gasoline hydrotreating catalyst and eliminates nitrogen oxide emissions. At the same time, it not only improves the morphology of the Co(Ni)-Mo-S active phase in the catalyst, but also significantly increases the amount of medium-strong acid. Therefore, the obtained catalyst can exhibit excellent comprehensive performance of deep desulfurization, significant reduction of olefins and maintenance of octane number for FCC gasoline. Attached Figure Description

[0027] Figure 1 The NH3-TPD curves are for the catalysts prepared in Example 1 and Comparative Example 3 of this invention. Detailed Implementation

[0028] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0029] The evaluation feedstock was FCC gasoline with a sulfur content of approximately 240 mg / kg and an olefin content of approximately 24 v%. The evaluation apparatus was a 200 mL fixed-bed reactor.

[0030] Evaluation and analysis methods:

[0031] (1) SH / T 0689-2000 is used to determine the total sulfur content of catalytic cracking gasoline and its hydrotreated products;

[0032] (2) GB / T 5487-1995 is used to determine the research octane number (RON) of catalytic cracking gasoline and its hydrotreated products;

[0033] (3) GB / T 11132 is used to determine the olefin content of catalytic cracking gasoline and its hydrotreated products.

[0034] Example 1

[0035] In this embodiment, EDTA was used to prepare FCC gasoline hydrotreating catalyst (CAT-1) using a "one-step impregnation-no-calcination" process.

[0036] First, 375g of H-ZSM-5 molecular sieve, 150g of pseudoboehmite powder HC-07 (produced by Shandong Xingdu Chemical Co., Ltd., which produces alumina with a water loss of about 30wt%), and 32.5g of guar gum powder were mixed evenly. Then, 16.9g of concentrated nitric acid (65wt%) and 180g of deionized water were added. After thorough kneading, the mixture was shaped in an extruder, dried, and calcined to obtain γ-Al2O3-ZSM-5 carrier.

[0037] Then, at 10°C, a mixture containing EDTA (analytical grade), cobalt nitrate (Co(NO3)2 6H2O, analytical grade), and ammonium heptamolybdate ((NH4)6Mo7O) was prepared. 24 A co-impregnation solution of 4H2O (analytical grade) was prepared, and concentrated ammonia (industrial grade) was added. The pH of the solution was adjusted to 9.8 within 0.5 h. The molar ratio of the complexing agent EDTA to Co in this solution was 1.4. This solution was then impregnated onto 200 g of γ-Al2O3-ZSM-5 support at 10 °C with an equal volume. After aging at 10 °C for 4 h and drying at 120 °C for 4 h, a single-impregnation, non-roasted semi-finished product was obtained. This single-impregnation, non-roasted semi-finished product was loaded into a 200 mL fixed-bed reactor for sulfidation. The sulfided oil consisted of a sulfiding agent and straight-run naphtha. The sulfiding agent was carbon disulfide with a concentration of 1.5 wt.%. The sulfidation pressure was 2.0 MPa, the hydrogen-to-oil volume ratio was 300:1, and the sulfided oil volume hourly space velocity was 1.5 h⁻¹. -1 The heating process was carried out under a nitrogen atmosphere, with the temperature increased from room temperature to 180°C at a rate of 30°C / h and held for 2 hours. Then, the nitrogen atmosphere was switched to a hydrogen atmosphere, and sulfurized oil was injected. The temperature was increased from 150°C to 230°C at a rate of 20°C / h and held for 4 hours. Subsequently, the temperature was increased from 230°C to 280°C at a rate of 20°C / h and held for 8 hours, completing the sulfurization process. After sulfurization, a high-performance FCC gasoline hydrotreating catalyst (CAT-1) was obtained. The active metal content of this catalyst, calculated as oxides, included 3.8 wt% Co₂O₃, 5.0 wt% MoO₃, and an atomic molar ratio of S / (Co+Mo) of 1.8. 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio was 68.2%.

[0038] Example 2

[0039] The catalyst (CAT-2) prepared in this embodiment differs from that in Example 1 in the following ways: Nickel nitrate (Co(NO3)2·6H2O, analytical grade) is used instead of cobalt nitrate (Co(NO3)2·6H2O, analytical grade); the preparation temperature and time of the co-impregnation solution are 15°C and 0.8 h, respectively; the drying temperature and drying time are 110°C and 5 h, respectively; the sulfiding agent is dimethyl disulfide; the sulfidation pressure is 1.5 MPa; the hydrogen-to-oil volume ratio is 250:1; and the sulfidation oil volume hourly space velocity is 1.2 h⁻¹. -1 .

[0040] The active metal content in CAT-2, calculated as oxides, includes 1.86 wt% NiO, 5.12 wt% MoO3, and an atomic molar ratio of S / (Ni+Mo) of 1.8, Mo... 4+ / (Mo 4+ +Mo 5+ +Mo6+ The ratio was 68.3%.

[0041] Example 3

[0042] The catalyst (CAT-3) prepared in this embodiment differs from that in Example 1 in that cobalt nitrate is replaced with cobalt acetate; EDTA is replaced with triacetic acid; the preparation temperature and time of the co-impregnation solution are 20°C and 1.0 h, respectively; the drying temperature and drying time are 115°C and 4.5 h, respectively; the sulfiding agent is methanethiol; the sulfidation pressure is 1.6 MPa; the hydrogen-to-oil volume ratio is 270:1; and the sulfidation oil volume hourly space velocity is 1.6 h⁻¹. -1 .

[0043] The active metal content in CAT-3, calculated as oxides, includes 7.6 wt% Co₂O₃, 10.0 wt% MoO₃, and the atomic molar ratio of S / (Co+Mo) and Mo... 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio of ) is the same as that of CAT-1.

[0044] Example 4

[0045] The catalyst (CAT-4) prepared in this embodiment differs from that in Example 1 in that the H-ZSM-5 molecular sieve is replaced with SAPO-11 molecular sieve; cobalt nitrate is replaced with cobalt carbonate; ammonium heptamolybdate is replaced with ammonium tetramolybdate; and EDTA is replaced with cyclohexanediaminetetraacetic acid. The preparation temperature and time of the co-impregnation solution are 25°C and 1.2 h, respectively; the drying temperature and drying time are 125°C and 4.0 h, respectively; the sulfiding agent is ethanethiol; the sulfidation pressure is 1.9 MPa; the hydrogen-to-oil volume ratio is 320:1; and the sulfidation oil volume hourly space velocity is 1.8 h⁻¹. -1 .

[0046] The active metal content in CAT-4, calculated as oxides, includes 9.5 wt% Co₂O₃, 12.5 wt% MoO₃, and the atomic molar ratio of S / (Co+Mo) and Mo... 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio of ) is the same as that of CAT-1.

[0047] Example 5

[0048] The catalyst (CAT-5) prepared in this embodiment differs from that in Example 1 in the following ways: H-ZSM-5 is replaced with HMOR; EDTA is replaced with ethylenediamine; and ammonium heptamolybdate is replaced with ammonium tetrathiomolybdate. The preparation temperature and time of the co-impregnation solution are 27°C and 1.0 h, respectively; the drying temperature and drying time are 128°C and 4.1 h, respectively; the sulfiding agent is sulfide; the sulfidation pressure is 2.4 MPa; the hydrogen-to-oil volume ratio is 340:1; and the sulfidation oil volume hourly space velocity is 1.9 h⁻¹. -1 .

[0049] The active metal content, S / (Co+Mo) atomic molar ratio, and Mo content of CAT-5 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratios of all of them are the same as those of CAT-1.

[0050] Example 6

[0051] The catalyst (CAT-6) prepared in this embodiment differs from that in Example 1 in that the pseudoboehmite powder HC-07 is replaced with aluminum hydroxide powder, and EDTA is replaced with ethylene glycol. The molar ratio of ethylene glycol to Co is 1.2. The preparation temperature and time of the co-impregnation solution are 30°C and 1.0 h, respectively; the drying temperature and drying time are 130°C and 4.0 h, respectively; the sulfiding agent is dimethyl sulfide; the sulfidation pressure is 2.5 MPa; the hydrogen-to-oil volume ratio is 350:1; and the sulfidation oil volume hourly space velocity is 3.0 h⁻¹. -1 .

[0052] Compared to CAT-1, CAT-6 has the same active metal content, with an atomic molar ratio of S / (Co+Mo) of 1.5 and Mo... 4+ / (Mo 4 + +Mo 5+ +Mo 6+ The ratio was 68.1%.

[0053] Example 7

[0054] The catalyst (CAT-7) prepared in this embodiment differs from that in Example 1 in that H-ZSM-5 is replaced with Hβ, EDTA is replaced with cyclohexanediaminetetraacetic acid, and the molar ratio of cyclohexanediaminetetraacetic acid to Co is 2.2.

[0055] Compared to CAT-1, CAT-7 has the same active metal content, with a S / (Co+Mo) molar ratio of 1.6 and a Mo... 4+ / (Mo 4+ +Mo 5+ +Mo 6+The ratio was 65.3%.

[0056] Example 8

[0057] The catalyst (CAT-8) prepared in this embodiment differs from that in Example 2 in that nickel acetate is used instead of nickel nitrate, and the molar ratio of EDTA to Ni is 1.5.

[0058] The active metal content in CAT-8, calculated as oxides, is 1.86 wt% NiO and 5.12 wt% MoO3, with an atomic molar ratio of S / (Ni+Mo) of 1.9 and Mo... 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio was 69.3%.

[0059] Example 9

[0060] The catalyst (CAT-9) prepared in this embodiment differs from that in Example 2 in that nickel carbonate is used instead of nickel nitrate, and the pH of the co-impregnation solution is 8.2.

[0061] The active metal content in CAT-9, calculated as oxides, includes 3.7 wt% NiO, 10.2 wt% MoO3, and an atomic molar ratio of S / (Ni+Mo) of 1.6, with Mo... 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio was 67.5%.

[0062] Comparative Example 1

[0063] The catalyst (CAT-D1) prepared in this embodiment differs from that in Example 1 in that the pH of the impregnation solution is 7.5.

[0064] Compared to CAT-1, CAT-D1 has the same active metal content, but the atomic molar ratio of S / (Co+Mo) is 1.3, and the Mo content is higher. 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio was 61.8%.

[0065] Comparative Example 2

[0066] The catalyst (CAT-D2) prepared in this embodiment differs from that in Example 1 in that the molar ratio of EDTA to Co is 3.0.

[0067] Compared to CAT-1, CAT-D2 has the same active metal content, with a S / (Co+Mo) molar ratio of 1.4 and a Mo...4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio of ) is 60.5%.

[0068] Comparative Example 3

[0069] This comparative example describes the preparation of an industrial FCC gasoline hydrotreating catalyst (CAT-D3) without a complexing agent using a "two-step impregnation-two-step calcination" process. The preparation method is the same as in Example 1, employing the same support and sulfidation process, the difference being the use of the traditional "two-step impregnation-two-step calcination" process. First, a mixture containing 14.5g of ammonium heptamolybdate ((NH4)6Mo7O) was prepared. 24 A solution containing 4g cobalt nitrate (Co(NO3)2·6H2O, analytical grade), 40g concentrated ammonia (industrial grade), and 40g deionized water was impregnated onto 200g of γ-Al2O3-ZSM-5 support by equal volumes. After aging at room temperature for 3 hours, drying at 120℃ for 4 hours, and calcining at 550℃ for 4 hours, a first-leaching semi-finished product was obtained. Then, an aqueous solution containing 15.6g cobalt nitrate (Co(NO3)2·6H2O, analytical grade) and 80g deionized water was impregnated onto the first-leaching semi-finished product by equal volumes. After aging at room temperature for 4 hours, drying at 120℃ for 4 hours, and calcining at 550℃ for 4 hours, a second-leaching semi-finished product was obtained. Finally, the second-leaching semi-finished product was loaded into a fixed-bed reactor for sulfidation. After sulfidation, CAT-D3 was obtained.

[0070] Compared to CAT-1, CAT-D3 has the same active metal content, with a S / (Co+Mo) molar ratio of 1.0 and a Mo... 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio was 55.9%.

[0071] The comparative characterization and evaluation methods and experimental data of CAT-1 to CAT-9 with CAT-D1, CAT-D2 and CAT-D3 are as follows:

[0072] 1. Comparative characterization of ammonia adsorption-desorption (NH3-TPD). 200 mg of catalyst was placed in the U-tube reactor of an AutoChem II 2920 fully automated chemisorption analyzer from Micron Instruments, USA. The sample was then cooled to 100 °C and ammonia was adsorbed at this temperature for 5 min. Afterward, the sample was purged with helium (35 mL / min, NTP) to eliminate physical adsorption. Finally, the sample was heated from 100 °C to 550 °C (10 °C / min) for NH3-TPD signal detection.

[0073] Figure 1 These are the NH3-TPD curves for CAT-1 and CAT-D3. (From...) Figure 1It can be seen that both CAT-1 and CAT-D3 show two distinct NH3 desorption peaks. The NH3 desorption peak at 100-300℃ belongs to the weakly acidic site, while the NH3 desorption peak at 300-550℃ belongs to the strong acidic site. However, CAT-1 has a higher content of medium-strong acid in the 200-550℃ range.

[0074] Table 1 shows the NH3-TPD acidity of the catalysts. As can be seen from Table 1, compared with CAT-D3, the catalysts CAT-1 to CAT-9, CAT-D1, and CAT-D2 of this invention have higher weak acidity, medium-strong acidity, and total acidity, with a significant increase in medium-strong acidity. This is attributed to the interaction between the complexing agent and the Al on the support surface during the preparation process. 3+ The preferential interaction of the metal protects the medium-to-strong acidic sites on the carrier surface from being covered by the metal, so that more acidic sites can be released after sulfidation (decomposition of the complexing agent).

[0075] Table 1. NH3-TPD acidity of the catalyst

[0076] project Weak acid content, μmol / g Medium-strong acid content, μmol / g Total acid content, μmol / g CAT-1 160 491 651. CAT-2 172 500 672 CAT-3 153 480 633 CAT-4 250 531 781 CAT-5 220 507 727 CAT-6 155 485 640 CAT-7 172 530 702 CAT-8 160 491 651 CAT-9 159 482 641 CAT-D1 156 461 617 CAT-D2 161 495 656 CAT-D3 144 308 452

[0077] X-ray photoelectron spectroscopy (XPS) comparative characterization. XPS data were acquired on a VG ESCALABMKII spectrometer equipped with a multi-channel detector under the following conditions: Al Kα radiation, radiation energy 1486.6 eV, power 150 W, 500 μm beam spot, and vacuum system performance better than 5 × 10⁻⁶. -9 mbar, flux energy 30 eV, binding energy corrected using the C1s peak (284.6 eV) as the standard. XPSPEAK-V4.1 software was used for data acquisition and analysis.

[0078] Table 2 XPS analysis data of the catalyst

[0079]

[0080]

[0081] Table 2 shows the XPS analysis data of the catalysts. As can be seen from Table 2, CAT-1 to CAT-9, as well as CAT-D1 and CAT-D2, all exhibit higher Mo content compared to CAT-D3. 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio of S / (Co(or Ni)+Mo) and the surface atomic ratio of S / (Co(or Ni)+Mo) indicate that the gasoline hydrotreating catalyst prepared in this invention has a large amount of MoS2 and CoMoS active phases.

[0082] 3. High-resolution transmission electron microscopy (HRTEM) comparative characterization. HRTEM images were taken on an F20 electron microscope manufactured by FEI Corporation, with an accelerating voltage of 200 kV. Before testing, the powder sample was ultrasonically dispersed with ethanol, and a certain amount of the clear liquid was dropped onto an ultrathin carbon support film microgrid. After being fully dried, the images were taken.

[0083] For each catalyst sample, 10 HRTEM images were randomly selected, and the average length of 250–300 metal sulfide lamellars was calculated according to formulas (1) and (2). and number of stacking layers

[0084]

[0085]

[0086] Among them, L i N represents the length of a single lamellar crystal. i n represents the number of stacked layers of a single lamellar crystal. i The number of lamellae of the same length or the number of stacked layers.

[0087] Table 3. Average length and average number of stacking layers of MoS2 lamellar crystals in the catalyst.

[0088]

[0089] After statistical analysis and calculation, the average length and average number of stacked layers of the catalyst active phase layer are shown in Table 3. Table 3 shows that CAT-1 to CAT-9, as well as CAT-D1 and CAT-D2, have shorter average lengths of MoS2-like wafers and fewer average stacked layers compared to CAT-D3. This is attributed to the fact that the present invention uses a simple "one-step impregnation-no-calcination" preparation process, by adding a complexing agent to the active metal component impregnation solution, resulting in weaker interaction between the MoS2-like wafers and the support.

[0090] 4. A 200 mL fixed-bed reactor was used, with FCC gasoline containing approximately 240 mg / kg sulfur and 24% olefins as feedstock, at a reaction temperature of 360℃, a reaction pressure of 2.0 MPa, and a volumetric hourly space velocity of 2.0 h⁻¹. -1 Under the condition of a hydrogen-to-oil volume ratio of 300:1, CAT-1 to CAT-9, as well as CAT-D1, CAT-D2, and CAT-D3, were compared and evaluated.

[0091] Table 4 presents the main comparative evaluation data of the catalyst. As shown in Table 4, compared with CAT-D3, the catalyst of this invention has a higher average desulfurization rate and average olefin reduction in hydrogenated gasoline products, but a smaller average octane number loss. This is attributed to the synergistic regulation of the Co-Mo-S active sites and the medium-to-strong acidity point by the complexing agent.

[0092] Table 4 Comparative evaluation data of catalysts

[0093] catalyst Average desulfurization rate, % Average olefin decrease, v% Average RON loss CAT-1 96.6 11.3 1.45 CAT-2 97.1 11.5 1.42 CAT-3 95.4 11.0 1.35 CAT-4 94.1 11.8 1.40 CAT-5 96.7 11.6 1.42 CAT-6 88.9 10.4 1.30 CAT-7 89.1 10.3 1.28 CAT-8 97.8 11.0 1.31 CAT-9 90.6 10.5 1.30 CAT-D1 83.4 9.1 1.40 CAT-D2 86.5 9.5 1.42 CAT-D3 62.2 7.8 1.50

[0094] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a catalyst for the hydrotreating of catalytic cracking gasoline, characterized in that, Includes the following steps: (1) Alumina powder and acidic molecular sieve are mixed, extruded, dried and calcined to obtain a catalyst support; (2) Prepare a co-impregnation solution containing a complexing agent and an active metal CoMo or NiMo, and adjust the pH value of the co-impregnation solution to be greater than 8.

1. The atomic molar ratio of the complexing agent to Co or Ni in the co-impregnation solution is 1.2-2.

2. (3) The co-impregnation liquid is impregnated onto the catalyst support in equal volume, and after aging and drying at room temperature, a single-impregnation non-calcination semi-finished product is obtained; (4) The sulfidation step (3) yields a hydrogenation-modified catalyst by dipping and calcining the semi-finished product. The acidic molecular sieve is one or more of H-ZSM-5, SAPO-11, Hβ, and HMOR; Mo in hydroretrograde catalyst 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio of ) is 60-100%; the average length of MoS2 wafers is 3.5-4.5; the average number of stacked layers of MoS2 wafers is 3.0-4.

0.

2. The preparation method of the catalytic cracking gasoline hydrotreating catalyst according to claim 1, characterized in that, In step (2), the pH value of the co-impregnation solution is adjusted to be greater than 8.2, and the atomic molar ratio of the complexing agent to Co or Ni in the co-impregnation solution is 1.5-1.

7.

3. The preparation method of the catalytic cracking gasoline hydrotreating catalyst according to claim 1, characterized in that, The alumina powder is boehmite and / or aluminum hydroxide powder.

4. The preparation method of the catalytic cracking gasoline hydrotreating catalyst according to claim 1, characterized in that, The alumina powder is boehmite powder.

5. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, The acidic molecular sieve is H-ZSM-5 and / or SAPO-11.

6. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, The complexing agent is one or more of ethylenediaminetetraacetic acid, aziridine triacetic acid, ethylenediamine, cyclohexanediaminetetraacetic acid, citric acid, and ethylene glycol.

7. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, The complexing agent is one or more of ethylenediaminetetraacetic acid, aziridine triacetic acid, ethylenediamine, and cyclohexanediaminetetraacetic acid.

8. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, In step (2), the temperature for preparing the co-impregnation solution is 10-90 ℃; the preparation time for the impregnation solution is 0.2-4 h.

9. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, In step (2), the temperature for preparing the co-impregnation solution is 10-30 ℃; the preparation time for the impregnation solution is 0.5-2 h.

10. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, The active metal Mo source in the co-impregnation solution is one or more of ammonium heptamolybdate, ammonium tetramolybdate, and ammonium tetrathiomolybdate; the active metal Co source in the co-impregnation solution is one or more of cobalt nitrate, cobalt acetate, and cobalt carbonate; and the active metal Ni source in the co-impregnation solution is one or more of nickel nitrate, nickel acetate, and nickel carbonate.

11. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, The active metal Mo source in the co-impregnation solution is ammonium heptamolybdate and / or ammonium tetrathiomolybdate; the active metal Co source in the co-impregnation solution is cobalt nitrate and / or cobalt acetate; and the active metal Ni source in the co-impregnation solution is nickel nitrate and / or nickel acetate.

12. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, In step (3), the drying temperature is 100-140℃ and the drying time is 2-8 h.

13. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, In step (3), the drying temperature is 110-130℃ and the drying time is 4-6 h.

14. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, In step (4), the sulfidation step is carried out in a fixed-bed reactor, using sulfidation oil containing sulfidation reagents. The sulfidation reagents are one or more of dimethyl disulfide, carbon disulfide, methanethiol, ethanethiol, dimethyl sulfide, and sulfides. The sulfidation temperature is 270-350℃; the sulfidation time is 20-100 h; the sulfidation pressure is 1.0-3.0 MPa; and the volume hourly space velocity of the sulfidation oil is 1.0-3.0 h⁻¹. -1 The hydrogen / oil volume ratio is 200:1-500:

1.

15. The method for preparing the catalytic cracking gasoline hydrotreating catalyst according to claim 14, characterized in that, The sulfiding agent is dimethyl disulfide and / or carbon disulfide; the sulfidation temperature is 280-300℃; the sulfidation time is 25-50 h; the sulfidation pressure is 1.5-2.5 MPa; and the sulfidation oil volume hourly space velocity is 1.0-2.0 h⁻¹. -1 The hydrogen / oil volume ratio is 250:1-350:

1.

16. The method for preparing the catalyst for catalytic cracking gasoline hydrotreating according to claim 1, characterized in that, When the active metal is CoMo, the active metal, based on oxides, comprises 0.2-20.0 wt% Co₂O₃, 2.0-20.0 wt% MoO₃, and an atomic molar ratio of S / (Co+Mo) of 1.0-3.

0. When the active metal is NiMo, the active metal, based on oxides, comprises 0.2-20.0 wt% NiO, 2.0-20.0 wt% MoO₃, and an atomic molar ratio of S / (Ni+Mo) of 1.0-3.

0. The Mo content in the hydrorefining catalyst... 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio of ) is 65-100%, the total acid content is 630-1500 μmol / g; the medium strong acid is 460-1000 μmol / g; the average length of MoS2 wafers is 3.8-4.2, and the average number of stacked layers of MoS2 wafers is 3.4-3.

8.

17. The method for preparing the catalytic cracking gasoline hydrotreating catalyst according to claim 16, characterized in that, When the active metal is CoMo, the active metal, based on oxides, comprises 0.5-15.0 wt% Co₂O₃, 4.0-14.0 wt% MoO₃, and an atomic molar ratio of S / (Co+Mo) of 1.6-2.

5. When the active metal is NiMo, the active metal, based on oxides, comprises 0.5-15.0 wt% NiO, 4.0-14.0 wt% MoO₃, and an atomic molar ratio of S / (Ni+Mo) of 1.6-2.

5. The Mo content in the hydrorefining catalyst... 4+ / (Mo 4+ +Mo 5+ +Mo 6+ The ratio of ) is 65-100%, and the total acid content is 640-1000 μmol / g; for moderately strong acids, it is 480-800 μmol / g.

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