A hydrocracking catalyst, its preparation method and use

Abstract

The application provides a kind of hydrocracking catalyst, first molecular sieve is mixed with inorganic refractory oxide as carrier, by impregnation method, introduce group VIB metal salt and group VIII metal salt, sulfurization, obtain catalyst precursor;Again, introduce molecular sieve to the catalyst precursor, then dry and calcine.The preparation method of the application, part of molecular sieve is mixed in carrier, a small part of molecular sieve is introduced into the catalyst in the form of loading on the surface of carrier, and the applicant finds in research, first group VIB metal and group VIII metal are introduced and sulfurized, then molecular sieve is introduced, and the effect of molecular sieve is better, because molecular sieve can directly react with group VIB metal sulfide, form new active phase, and the catalytic effect is better, so the utilization rate of molecular sieve and active metal prepared by the method of the application is higher, and the active effect is better, which is beneficial to reduce the amount of molecular sieve and reduce the cost of catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil hydrogenation, in particular to a hydrocracking catalyst, and a preparation method and application thereof. BACKGROUND

[0002] With the overcapacity of diesel production and the shortage of chemical raw materials, more and more oil refining enterprises use hydrocracking technology to convert raw materials into naphtha, thereby reducing the yield of diesel. The performance of the catalyst in the hydrocracking technology has a significant impact on the product structure.

[0003] CN202011133094.1 discloses a preparation method of a hydrocracking catalyst, the hydrocracking catalyst and application. The preparation method of the hydrocracking catalyst comprises: (i) preparing a Beta / Al-SBA-15 composite molecular sieve; (ii) adding the Beta / Al-SBA-15 composite molecular sieve obtained in step (i) to an alumina dry gel powder and then to an acidic solution, shaping, drying and calcining to obtain a hydrocracking catalyst carrier; (iii) impregnating the hydrocracking catalyst carrier with an impregnation solution containing a polyhydroxy compound, and then drying to obtain a modified hydrocracking catalyst carrier; (iv) impregnating the modified hydrocracking catalyst carrier obtained in step (iii) with an impregnation solution containing an active metal component, and then drying and calcining to obtain a hydrocracking catalyst. The content of the molecular sieve in the catalyst is 25-45% by weight of the carrier, but the performance of the molecular sieve in the catalyst is not fully utilized, and many molecular sieves are wrapped in alumina and lose activity. At the same time, the improvement of the activity of the catalyst mainly comes from the increase of the total content of the molecular sieve, which also leads to the increase of the cost of the catalyst. At the same time, the catalyst has a high requirement for the nitrogen content in the raw oil during use to prevent the poisoning of the molecular sieve in the catalyst.

[0004] CN201711015607.7 discloses a hydrocracking catalyst, a preparation method thereof and a method for heavy oil hydrocracking. The hydrocracking catalyst contains catalyst A and catalyst B. Catalyst A includes a carrier and a first metal promoter loaded thereon; the carrier is formed by a binder and a silicon-aluminum molecular sieve; the content of the silicon-aluminum molecular sieve is 20-70% by weight, the content of the first metal promoter is 1-30% by weight, and the content of the binder is 5-50% by weight; catalyst B contains 5-35% by weight of alumina, 5-40% by weight of silicon oxide, 1-20% by weight of a second metal promoter and 1-45% by weight of an alkaline metal oxide. But the performance of the molecular sieve in the catalyst is not fully utilized, and many molecular sieves are wrapped in alumina and lose activity. At the same time, the improvement of the activity of the catalyst mainly comes from the increase of the total content of the molecular sieve, which also leads to the increase of the cost of the catalyst. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a hydrocracking catalyst, which adopts kneading part of the molecular sieve into the carrier, loading another part of the molecular sieve on the surface of the carrier, and forming a new active phase with specific active components, so as to improve the utilization rate of the molecular sieve, and meanwhile, has high hydrogenation activity and flexible cracking activity.

[0006] In order to achieve the above technical purposes, the technical scheme of the present application is as follows:

[0007] The first aspect of the present application is to provide a preparation method of a hydrocracking catalyst, comprising the following steps:

[0008] (1) mixing the molecular sieve with inorganic refractory oxide as a carrier, introducing the Group VIB metal salt and the Group VIII metal salt into the carrier by impregnation, and sulfidizing to obtain a catalyst precursor;

[0009] (2) introducing the molecular sieve into the catalyst precursor, and then drying and calcining.

[0010] Further, the inorganic refractory oxide is selected from at least one of aluminum oxide, silicon oxide, titanium oxide and zirconium oxide, and is preferably aluminum oxide.

[0011] Further, in the mixed carrier formed in step (1), the molecular sieve accounts for 5-80% by weight, preferably 8-50%, further preferably 10-30%, and most preferably 10-20%.

[0012] Further, the impregnation in step (1) is equal-volume impregnation or supersaturation impregnation. The Group VIB metal salt and the Group VIII metal salt can be introduced into the carrier by co-impregnation, or can be introduced into the carrier by stepwise impregnation, and the order of introduction of the two is not particularly limited. Preferably, the Group VIB metal salt and the Group VIII metal salt are introduced into the carrier by co-impregnation.

[0013] Further, after the impregnation of step (1) is completed, a drying process is further included. The drying conditions include a temperature of 20-90°C and a time of 4-16 hours.

[0014] Further, the impregnation process of step (1) further preferably adds an organic aid in the impregnation solution to facilitate the dispersion of the active components. The organic aid is a compound containing a hydroxyl group and / or a carboxyl group with a carbon atom number of 2-10. More specifically, the organic aid is selected from at least one of ethylene glycol, glycerol, butanediol, pentanediol, acetic acid, citric acid, malonic acid, succinic acid and glutaric acid.

[0015] Further, the category of the Group VIB metal salt and the Group VIII metal salt is selected based on the subsequent conversion into the respective metal sulfide, preferably, the Group VIB metal salt is a phosphate salt and / or an ammonium salt of the Group VIB metal, and the Group VIII metal salt is at least one of a nitrate salt, an acetate salt and a sulfate salt of the Group VIII metal.

[0016] Further, the sulfuration is dry sulfuration or wet sulfuration. The dry sulfuration and the wet sulfuration of the present application have the conventional interpretation in the art.

[0017] Preferably, the conditions of the sulfuration include: a sulfuration pressure of 3.2-6.4 MPa, a sulfuration temperature of 250-400℃, a sulfuration time of 4-12 h, and a hydrogen flow rate of 2-25 mL·min -1 ·g -1 .

[0018] Further, the dry sulfuration agent used in the dry sulfuration is hydrogen sulfide. Specifically, the sulfuration gas used in the dry sulfuration includes hydrogen sulfide and hydrogen. Preferably, the volume content of hydrogen sulfide in the sulfuration gas is 1-10%.

[0019] Further, the wet sulfuration agent used in the wet sulfuration is at least one of carbon disulfide, dimethyl disulfide, methyl sulfide and n-butyl sulfide. Specifically, the sulfuration liquid used in the wet sulfuration includes the wet sulfuration agent and an organic solvent. Preferably, the organic solvent is selected from at least one of cyclohexane, n-heptane, aviation kerosene and diesel. The mass fraction of the wet sulfuration agent in the sulfuration liquid is selected in a wide range, preferably 2%-7%, and more preferably 4%-6%. Preferably, the flow rate of the sulfuration liquid is 0.5-5 mL·h -1 ·g -1 , preferably 1-4 mL·h -1 ·g -1 .

[0020] Further, the amount of the Group VIB metal salt and the Group VIII metal salt is such that, in the prepared catalyst, the content of the Group VIB metal sulfide, based on the sulfide, is 10-30 wt%, preferably 15-28 wt%, and the content of the Group VIII metal sulfide, based on the sulfide, is 2-10 wt%, preferably 4-8 wt%, based on the total weight of the catalyst.

[0021] In the present application, the content of Group VIB metal sulfide and Group VIII metal sulfide is jointly characterized by inductively coupled plasma (ICP) and XPS energy spectrum. Specifically, the total content of Group VIB metal and the total content of Group VIII metal in the catalyst are characterized by ICP, and then the content of metal elements in different valence states in the catalyst is quantitatively characterized by XPS energy spectrum. The measurement conditions of the XPS energy spectrum include: analysis chamber vacuum degree ≤ 5 × 10 -10 mbar; preparation chamber vacuum degree ≤ 1 × 10 -7 mbar; double anode sensitivity 4.5 × 10 6 , energy resolution 1.0 eV; monochromator sensitivity 1.4 × 10 5 , energy resolution 0.5 eV. Mo3d, W4f, Co2p and Ni2p energy spectrum are fitted and peaked by XPSPEAK Version 4.0, and the content of metal elements in different valence states in the catalyst is calculated according to the peak area.

[0022] Further, the amount of the catalyst precursor and the molecular sieve in step (2) is such that the content of the molecular sieve introduced later in the catalyst prepared is 1-12 wt%, preferably 1.5-8 wt%, and more preferably 2-6 wt%, based on the total weight of the catalyst. The content of the molecular sieve in the catalyst is not particularly limited in the present application, and can be determined by the amount of silicon oxide combined with the crystal form of the molecular sieve determined by XRD, or can be calculated by the feed amount during catalyst preparation.

[0023] Further, the molecular sieve is selected from at least one of Y-type molecular sieve, ZSM-5 molecular sieve, β-type molecular sieve and MCM-41 molecular sieve. The molecular sieve can be commercially available or synthesized by the existing method, and the present application does not have a particular limitation.

[0024] Further, the method for introducing the molecular sieve into the catalyst precursor in step (2) is not particularly limited, and can be directly mixed to obtain, or can be mixed with a molecular sieve precursor and then hydrothermally treated to obtain.

[0025] Further, the method for introducing the molecular sieve into the catalyst precursor in step (2) is carried out by at least one of the following ways:

[0026] (a) hydrothermally treating the catalyst precursor and the molecular sieve precursor, and carrying out the drying and calcination in step (3) under an inert atmosphere;

[0027] (b) mixing the catalyst precursor and the ball-milled molecular sieve in the presence of a solvent, and then carrying out the drying and calcination in step (3).

[0028] Further, the molecular sieve precursor can be a gel formed by hydrothermal treatment of a gel of the above-mentioned type. Preferably, in the method (a), the molecular sieve precursor comprises a gel formed by mixing a silicon source and / or an aluminum source, a precipitant, a template agent and water. The preparation method is well known to those skilled in the art, and the molecular sieve can be formed by a precipitation method or a sol-gel method.

[0029] The types of the silicon source and / or the aluminum source, the precipitant and the template agent are well known to those skilled in the art. The silicon source is preferably selected from at least one of sodium silicate, tetraethyl orthosilicate, silica sol and chromatographic silica gel. The aluminum source is preferably selected from at least one of sodium aluminate, aluminum hydroxide and pseudo-boehmite. The precipitant is preferably selected from at least one of sodium hydroxide, ammonia and potassium hydroxide. The template agent is preferably selected from at least one of cetyltrimethylammonium bromide, ethylenediamine, n-butylamine, tetrapropylammonium bromide, ethanol, tetraethylammonium hydroxide, tetraethylammonium bromide, triethylamine, di-n-propylamine, diisopropylamine and methylcellulose.

[0030] Further, when the molecular sieve is a silicon-aluminum molecular sieve, the molar composition of the gel is n(SiO2):n(Al2O3):n(Na2O):n(template agent):n(H2O)=(5-30):1:(1-10):(1-10):(100-300).

[0031] Further, when the molecular sieve is a full-silica molecular sieve, the molar composition of the gel is n(SiO2):n(Na2O):n(template agent):n(H2O)=100:(10-30):(10-30):(1500-3000).

[0032] The conditions of the hydrothermal treatment are selected in a wide range according to the molecular sieve to be obtained. Preferably, the conditions of the hydrothermal treatment include a temperature of 90-200°C, a pressure of 0.1-2 MPa, a pH of 7.5-9 and a time of 5-48 hours.

[0033] Further, in the method (b), the particle size of the molecular sieve after ball milling is 0.1-10 nm, and more preferably 0.1-5 nm. The use of this preferred embodiment is more conducive to the function of the molecular sieve. The parameters and equipment of the ball milling are not particularly limited.

[0034] Further, the drying conditions in the step (2) include a temperature of 20-90°C and a time of 4-16 hours.

[0035] Further, the calcination conditions in the step (2) include a temperature of 300-500°C and a time of 2-5 hours.

[0036] Further, the drying and calcining in step (2) can be carried out in an inert atmosphere. The inert atmosphere is selected from at least one of nitrogen and inert gas.

[0037] The technical purpose of the second aspect of the present application is to provide the hydrocracking catalyst prepared by the above preparation method.

[0038] The present application prepares the hydrocracking catalyst by kneading the molecular sieve in the carrier and introducing the molecular sieve on the surface of the carrier, and part of the molecular sieve is introduced after loading the sulfided metal active component, which is beneficial to the direct action of the molecular sieve and the Group VIB metal sulfide, higher utilization of the molecular sieve and the active metal, better active effect, and reduction of the amount of the molecular sieve and the cost of the hydrocracking catalyst.

[0039] The technical purpose of the third aspect of the present application is to provide the application of the above hydrocracking catalyst in the hydrogenation of oil products, and the catalyst is used for the hydrocracking reaction of the oil products.

[0040] Further, the process conditions of the hydrocracking reaction are as follows: the pressure is 1.0-12.0 MPa, preferably 6.0-10.0 MPa, the hydrogen partial pressure accounts for 50%-95% of the total pressure, the volume space velocity is 0.1-10.0 h -1 , preferably 2.0-8.0 h -1 , the reaction temperature is 200-420℃, preferably 360-400℃, and the hydrogen / oil volume ratio is 10:1-1000:1, preferably 100:1-800:1.

[0041] Compared with the prior art, the catalyst of the present application has the following advantages:

[0042] In the prior art hydrocracking catalyst, the required content of the molecular sieve is high, resulting in high cost of the catalyst. In the preparation method of the present application, part of the molecular sieve is kneaded in the carrier, and a small part of the molecular sieve is introduced into the catalyst in the form of being loaded on the surface of the carrier, and the applicant found in the research that the Group VIB metal and the Group VIII metal are introduced and sulfided first, and then the molecular sieve is introduced, the effect of the molecular sieve is better, because the molecular sieve can directly react with the Group VIB metal sulfide to form a new active phase, and the catalytic effect is better, so the utilization of the molecular sieve and the active metal is higher, the active effect is better, the amount of the molecular sieve is reduced, and the cost of the catalyst is reduced.

[0043] Other features and advantages of the present application will be described in detail in the following specific embodiment part. DETAILED DESCRIPTION

[0044] The following non-limiting examples can provide a more complete understanding of the application to one of ordinary skill in the art, but are not intended to limit the application in any way.

[0045] The content of the Group VIB metal sulfide and the Group VIII metal sulfide can be jointly characterized by inductively coupled plasma ICP and XPS energy spectrum, and the specific method is described in the summary. The content of the molecular sieve in the carrier is calculated by the amount of the raw material, and the content of the molecular sieve introduced later is calculated by the weight difference between the catalyst precursor and the finally prepared catalyst.

[0046] Example 1

[0047] (1) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added to deionized water, and the molar ratio of each component was n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O)=13:2:6:3:170, and stirred to form a uniform sol, i.e. the precursor of Y molecular sieve, then hydrothermal treatment was carried out at 150℃, 1.0MPa, pH=8.0 for 10h, then filtered, washed with deionized water three times, then dried at 90℃ for 3h, and calcined at 500℃ for 3h to obtain Y molecular sieve. The Y molecular sieve was mixed with alumina powder, nitric acid, starch and deionized water, and the mass ratio of Y molecular sieve:alumina powder:nitric acid:starch:deionized water was 6.1:93.9:4:3:90, then kneaded, extruded and formed into strips, then dried at 90℃ for 10 hours, and calcined at 600℃ for 3 hours to obtain the carrier, wherein the content of Y molecular sieve was 6.1%.

[0048] The solution of nickel nitrate and ammonium heptamolybdate was impregnated into the above carrier by pore saturation impregnation, then dried at 80℃ for 3h, then sulfided by hydrogen gas containing 1.5% by volume H2S, the flow rate of hydrogen gas was 10mL·min -1 ·g -1 , the sulfidation temperature was 300℃, the sulfidation pressure was 3.2MPa, the sulfidation time was 4h, then cooled to room temperature in N2 atmosphere to obtain the catalyst precursor.

[0049] (2) The precursor of Y molecular sieve with the same composition as in step (1) and the catalyst precursor prepared in step (1) were mixed, then hydrothermal treatment was carried out at 150℃, 1.0MPa, pH=8.0 for 10h; then filtered, washed with deionized water three times, dried at 80℃ for 3h in a nitrogen atmosphere, and calcined at 450℃ for 3h to obtain catalyst C-1.

[0050] The weight percentage of each component in catalyst C-1 was as follows: MoS2 was 19.1%, NiS was 4.2%, Y molecular sieve in the carrier was 6.1%, the introduced Y molecular sieve was 2.5%, and the rest was alumina.

[0051] Example 2

[0052] (1) Sodium hydroxide, silica sol, sodium aluminate and n-butylamine were added to deionized water, wherein the molar ratio of each component was n(SiO2):n(Al2O3):n(Na2O):n(n-butylamine):n(H2O)=22:1:7:6:200, and stirring was performed to form a uniform sol, i.e. a precursor of ZSM-5 molecular sieve, which was then hydrothermally treated at 160°C, 1.0 MPa, pH=8.0 for 10h, and then filtered and washed with deionized water three times, and then dried at 90°C for 3h and calcined at 500°C for 3h to obtain ZSM-5 molecular sieve. The ZSM-5 molecular sieve was mixed with alumina powder, nitric acid, starch and deionized water, wherein the mass ratio of ZSM-5 molecular sieve:alumina powder:nitric acid:starch:deionized water was 11.2:88.8:4:3:90, and then kneaded, extruded and formed into a strip, and then dried at 90°C for 10h and calcined at 650°C for 3h to obtain a carrier, wherein the content of ZSM-5 molecular sieve was 11.2%.

[0053] The solution of nickel nitrate and ammonium heptamolybdate was impregnated into the above carrier by pore saturation impregnation, and then dried at 80°C for 3h, and then sulfided by using hydrogen gas containing 1.5% by volume of H2S, wherein the flow rate of hydrogen gas was 10mL·min -1 ·g -1 , the sulfidation temperature was 320°C, the sulfidation pressure was 3.6MPa, and the sulfidation time was 4h, and then the temperature was lowered to room temperature in a N2 atmosphere to obtain a catalyst precursor.

[0054] (2) The precursor of ZSM-5 molecular sieve with the same composition as in step (1) was mixed with the catalyst precursor prepared in step (1), and then hydrothermally treated at 130°C, 1.0 MPa, pH=8.5 for 24h; and then filtered, washed with deionized water three times, dried at 80°C for 3h in a nitrogen atmosphere, and calcined at 500°C for 3h to obtain catalyst C-2.

[0055] The weight percentage of each component in catalyst C-2 was as follows: MoS2 was 22%, NiS was 4.2%, ZSM-5 molecular sieve in the carrier was 11.2%, the post-introduced ZSM-5 molecular sieve was 3.6%, and the rest was alumina.

[0056] Example 3

[0057] (1) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added to deionized water, wherein the molar ratio of each component was n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O)=13:2:6:3:170, and stirred until a homogeneous sol, i.e. a precursor of Y zeolite, was formed. Then, the precursor was hydrothermally treated at 150°C, 1.0 MPa and pH=8.0 for 10 h, and then filtered and washed with deionized water three times. Then, the precursor was dried at 90°C for 3 h and calcined at 500°C for 3 h to obtain Y zeolite. The Y zeolite was mixed with alumina powder, nitric acid, starch and deionized water, wherein the mass ratio of Y zeolite:alumina powder:nitric acid:starch:deionized water was 12.1:87.9:4:3:90. Then, the mixture was kneaded, extruded and shaped, and then dried at 90°C for 10 h and calcined at 650°C for 3 h to obtain a carrier, wherein the content of Y zeolite was 12.1%.

[0058] The solution of nickel nitrate and ammonium heptamolybdate was impregnated into the carrier by pore saturation impregnation, and then dried at 90°C for 3 h. Then, the carrier was sulfidized by using hydrogen containing 1.5% by volume of H2S, wherein the flow rate of hydrogen was 10 mL·min-1, the sulfidization temperature was 350°C, the sulfidization pressure was 4.0 MPa, and the sulfidization time was 6 h. Then, the carrier was cooled to room temperature in a N2 atmosphere to obtain a catalyst precursor. -1 ·g -1

[0059] (2) Sodium aluminate and sodium hydroxide were dissolved in deionized water, and then tetraethylammonium bromide was added. The mixture was stirred vigorously, and silica sol was slowly added dropwise. The mixture was aged for 3 h, wherein the molar ratio of each component was n(SiO2):n(Al2O3):n(Na2O):n(tetraethylammonium bromide):n(H2O)=22:1:6:5:230. Then, the precursor of β zeolite was mixed with the catalyst precursor prepared in step (1), and then hydrothermally treated at 130°C, 1.5 MPa and pH=8.5 for 15 h. Then, the mixture was filtered, washed with deionized water three times, dried at 90°C for 3 h in a N2 atmosphere, and calcined at 500°C for 3 h to obtain catalyst C-3.

[0060] The weight percentage of each component in catalyst C-3 was as follows: MoS2 was 22%, NiS was 3.6%, Y zeolite in the carrier was 12.1%, β zeolite introduced later was 5.0%, and the rest was alumina.

[0061] Example 4

[0062] ​(1) Dissolve sodium metaaluminate, sodium hydroxide into deionized water, then add tetraethylammonium bromide, stir vigorously, slowly drop silica sol, and age for 3 h, wherein the molar ratio of each component is n(SiO2):n(Al2O3):n(Na2O):n(tetraethylammonium bromide):n(H2O) = 22:1:6:5:230, to form a precursor of β-type molecular sieve, then hydrothermally treat at 150 ℃, 1.0 MPa, pH = 8.0 for 10 h, then filter, wash with deionized water for three times, then dry at 90 ℃ for 3 h, and calcine at 500 ℃ for 3 h to obtain the β-type molecular sieve. Mix the β-type molecular sieve, alumina powder, nitric acid, starch and deionized water uniformly, wherein the mass ratio of the β-type molecular sieve: alumina powder: nitric acid: starch: deionized water is 15.1:84.9:4:3:90, then mix, extrude and shape, then dry at 90 ℃ for 10 h, and calcine at 650 ℃ for 3 h to obtain the carrier, wherein the content of the β-type molecular sieve is 15.1%.

[0063] Immerse the solution of nickel nitrate and ammonium heptamolybdate into the above carrier by pore saturation impregnation, then dry at 90 ℃ for 3 h, then sulfide treat by using hydrogen gas containing 1.5% by volume of H2S, the flow rate of hydrogen gas is 10 mL·min-1, the sulfidation temperature is 350 ℃, the sulfidation pressure is 4.2 MPa, and the sulfidation time is 5 h, then reduce to room temperature in a N2 atmosphere to obtain a catalyst precursor. -1 ·g -1

[0064] (3) Mix cetyltrimethylammonium bromide and sodium hydroxide, then add into deionized water, drop tetraethyl orthosilicate into the mixed solution after stirring, stir for 30 min, wherein the molar ratio of each component is n(SiO2):n(Na2O):n(cetyltrimethylammonium bromide):n(H2O) = 10:2:2:200, to form a precursor of MCM-41 molecular sieve, then mix with the catalyst precursor prepared in step (1), then hydrothermally treat at 130 ℃, 1.0 MPa, pH = 8.5 for 15 h; then filter, wash with deionized water for three times, dry at 80 ℃ for 3 h in a nitrogen atmosphere, and calcine at 450 ℃ for 3 h to obtain the catalyst C-4.

[0065] The weight percentage of each component in the catalyst C-4 is as follows: MoS2 is 21%, NiS is 4.3%, the β-type molecular sieve in the carrier is 15.1%, the MCM-41 molecular sieve introduced later is 3.8%, and the rest is alumina.

[0066] Example 5

[0067] ​(1) Dissolve sodium aluminate, sodium hydroxide into deionized water, then add tetraethylammonium bromide, stir vigorously, slowly drop silica sol, and age for 3 h, wherein the molar ratio of each component is n(SiO2):n(Al2O3):n(Na2O):n(tetraethylammonium bromide):n(H2O) = 22:1:6:5:230, to form a precursor of β molecular sieve, then hydrothermally treat at 150 ℃, 1.0 MPa, pH = 8.0 for 10 h, then filter, wash with deionized water three times, then dry at 90 ℃ for 3 h, and calcine at 500 ℃ for 3 h to obtain a β molecular sieve. Mix the β molecular sieve, alumina powder, nitric acid, starch, and deionized water uniformly, wherein the mass ratio of the β molecular sieve:alumina powder:nitric acid:starch:deionized water is 12.1:87.9:4:3:90, then mix and knead, extrude and shape, then dry at 90 ℃ for 10 h, and calcine at 650 ℃ for 3 h to obtain a carrier, wherein the content of the β molecular sieve is 12.1%.

[0068] Impregnate a solution of cobalt nitrate and ammonium heptamolybdate into the above carrier by pore saturation impregnation, then dry at 90 ℃ for 3 h, then sulfide treat by using hydrogen containing 1.5% by volume of H2S, the flow rate of hydrogen is 10 mL·min-1, the sulfidation temperature is 350 ℃, the sulfidation pressure is 4.2 MPa, and the sulfidation time is 5 h, then reduce to room temperature in a N2 atmosphere to obtain a catalyst precursor. -1 ·g -1

[0069] (2) Add sodium hydroxide, silica sol, sodium aluminate, and ethylenediamine into deionized water, wherein the molar ratio of each component is n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O) = 123:1:6:3:190, stir to form a uniform sol, i.e., a precursor of Y molecular sieve, mix with the catalyst precursor prepared in step (1), then hydrothermally treat at 120 ℃, 1.0 MPa, pH = 9.0 for 20 h; then filter, wash with deionized water three times, dry at 80 ℃ for 3 h in a nitrogen atmosphere, and calcine at 500 ℃ for 3 h to obtain a catalyst C-5.

[0070] The weight percentage of each component in the catalyst C-5 is as follows: MoS2 is 20.1%, CoS is 4.2%, the β molecular sieve in the carrier is 12.1%, the Y molecular sieve introduced later is 3.5%, and the rest is alumina.

[0071] Example 6

[0072] ​(1) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added to deionized water, wherein the molar ratio of each component was n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O)=13:2:6:3:170, and stirred to form a homogeneous sol, i.e. the precursor of Y molecular sieve, and then hydrothermally treated at 150°C, 1.0 MPa, pH=8.0 for 10h, and then filtered, washed with deionized water three times, and then dried at 90°C for 3h, and calcined at 500°C for 3h to obtain the Y molecular sieve. The Y molecular sieve was mixed with alumina powder, nitric acid, starch and deionized water, wherein the mass ratio of Y molecular sieve:alumina powder:nitric acid:starch:deionized water was 16.1:83.9:4:3:90, and then kneaded, extruded and formed, and then dried at 90°C for 10h, and calcined at 650°C for 3h to obtain the carrier, wherein the content of Y molecular sieve was 16.1%.

[0073] The solution of nickel nitrate and ammonium metatungstate was impregnated into the above carrier by pore saturation impregnation, and then dried at 90°C for 6h, and then sulfided by using hydrogen gas containing 1.5% by volume of H2S, the flow rate of hydrogen gas was 10mL·min -1 ·g -1 , the sulfidation temperature was 360°C, the sulfidation pressure was 4.0MPa, and the sulfidation time was 6h, and then cooled to room temperature in a N2 atmosphere to obtain the catalyst precursor.

[0074] (2) Sodium hydroxide, silica sol, sodium aluminate and n-butylamine were added to deionized water, wherein the molar ratio of each component was n(SiO2):n(Al2O3):n(Na2O):n(n-butylamine):n(H2O)=21:1:7:6:180, and stirred to form a homogeneous sol, i.e. the precursor of ZSM-5 molecular sieve, and then mixed with the catalyst precursor prepared in step (1), and then hydrothermally treated at 180°C, 1.0 MPa, pH=8.5 for 15h; and then filtered, washed with deionized water three times, dried at 90°C for 3h in a nitrogen atmosphere, and calcined at 500°C for 3h to obtain the catalyst C-6.

[0075] The weight percentage of each component in the catalyst C-6 was as follows: WS2 was 27.3%, NiS was 4.8%, Y molecular sieve in the carrier was 16.1%, ZSM-5 molecular sieve introduced later was 4.3%, and the rest was alumina.

[0076] Example 7

[0077] (1) Sodium hydroxide, silica sol, sodium aluminate and n-butylamine were added into deionized water, wherein the molar ratio of each component was n(SiO2):n(Al2O3):n(Na2O):n(n-butylamine):n(H2O)=22:1:7:6:200, and stirred to form a homogeneous sol, i.e. the precursor of ZSM-5 molecular sieve, which was then hydrothermally treated at 160°C, 1.0 MPa and pH=8.0 for 10 h, and then filtered and washed with deionized water for three times, and then dried at 90°C for 3 h and calcined at 500°C for 3 h to obtain ZSM-5 molecular sieve. The ZSM-5 molecular sieve was uniformly mixed with zirconium oxide powder, nitric acid, starch and deionized water, wherein the mass ratio of ZSM-5 molecular sieve: zirconium oxide powder: nitric acid: starch: deionized water was 15.1:84.9:4:3:90, and then kneaded, extruded and formed into strips, and then dried at 90°C for 10 h and calcined at 650°C for 3 h to obtain the carrier, wherein the content of ZSM-5 molecular sieve was 15.1%.

[0078] The solution of cobalt nitrate and ammonium metatungstate was impregnated into the above carrier by pore saturation impregnation, and then dried at 80°C for 3 h, and then sulfided by hydrogen gas containing 1.5% by volume of H2S, wherein the flow rate of hydrogen gas was 10 mL·min-1, the sulfidation temperature was 380°C, the sulfidation pressure was 3.6 MPa, and the sulfidation time was 4 h, and then the temperature was lowered to room temperature in a N2 atmosphere to obtain the catalyst precursor. -1 ·g -1

[0079] (2) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added into deionized water, wherein the molar ratio of each component was n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O)=13:1:6:3:200, and stirred to form a homogeneous sol, i.e. the precursor of Y molecular sieve, which was then mixed with the catalyst precursor prepared in step (1), and then hydrothermally treated at 130°C, 1.0 MPa and pH=8.5 for 15 h; and then filtered, washed with deionized water for three times, dried at 90°C for 3 h in a nitrogen atmosphere, and calcined at 480°C for 3 h to obtain catalyst C-7.

[0080] The weight percentage of each component in catalyst C-7 was as follows: WS2 was 22.8%, CoS was 5.2%, ZSM-5 molecular sieve in the carrier was 15.1%, Y molecular sieve introduced later was 3.5%, and the rest was zirconium oxide.

[0081] Example 8

[0082] ​The procedure of Example 2 was followed except that in step (2), the catalyst precursor prepared in step (1) was directly mixed with the ZSM-5 type molecular sieve (particle size of 0.2-2.0 nm) after ball milling, followed by the drying and calcination. The preparation of the ZSM-5 type molecular sieve included: sodium hydroxide, silica sol, sodium metaaluminate and n-butylamine were added to deionized water, wherein the molar ratio of each component was n(Si02):n(Al203):n(Na20):n(n-butylamine):n(H20)=22:1:7:6:200, stirred to form a homogeneous sol, then hydrothermally treated at 150°C, 1.0 MPa, pH=8.0 for 10h; then filtered, washed with deionized water three times, then dried at 90°C for 3h, calcined at 450°C for 3h to obtain catalyst C-8.

[0083] Comparative Example 1

[0084] Steps (1) and (2) were the same as Example 2, except that step (1) had no sulfidation process, and the sulfidation process was carried out after calcination in step (2), to obtain comparative catalyst DC-1.

[0085] Comparative Example 2

[0086] (1) ZSM-5 molecular sieve, alumina, nitric acid, starch and deionized water were mixed uniformly, wherein the mass ratio of Y type molecular sieve: porous carbon: nitric acid: starch: deionized water was 16.1:83.9:4:3:90, then kneaded, extruded and formed, then dried at 80°C for 10h, calcined at 600°C for 3h to obtain the carrier, wherein the content of ZSM-5 molecular sieve was 16.1%.

[0087] (2) A mixed solution of phosphomolybdic acid and nickel nitrate was impregnated into the carrier prepared in step (1), then dried at 90°C for 3h in a nitrogen atmosphere, calcined at 450°C for 3h, then sulfidation treatment was carried out, the sulfidation temperature was 320°C, the sulfidation pressure was 3.0 MPa, and the sulfidation time was 4h, then cooled to room temperature in a N2 atmosphere to obtain comparative catalyst DC-2.

[0088] The weight percentage of each component in catalyst DC-2 was: MoS2 was 22%, NiS was 4.2%, the content of ZSM-5 molecular sieve was 16.1%, and the rest was alumina.

[0089] In the above examples and comparative examples, the amount of the molecular sieve directly reacted with the Group VIB metal sulfide, calculated based on the silicon element, accounted for the proportion of the total amount of the molecular sieve, which was listed in Table 1.

[0090] Table 1

[0091]

[0092] Application Example 1

[0093] This application example illustrates the performance of the catalyst provided by the application for hydrocracking of biodiesel.

[0094] The evaluation feedstock oil used was VGO feedstock, which had the following main properties: distillation range 200-470°C, sulfur content 2.1%, nitrogen content 0.1%. A 200 mL fixed bed hydrogenation device was used to evaluate the hydrogenation reaction performance of the catalysts provided by the examples and the comparative examples. The evaluation reaction conditions were: operating pressure 8.4 MPa, reaction temperature 390°C, hydrogen / oil volume ratio 800:1, volume space velocity 3.0 h -1 The evaluation results after 100 h of reaction are shown in Table 2.

[0095] Table 2

[0096]

Claims

1. A method for preparing a hydrocracking catalyst, comprising the following steps: (1) Molecular sieve and inorganic refractory oxide are mixed as a support. By weight, the molecular sieve accounts for 5-80% of the mixed support. Group VIB metal salt and Group VIII metal salt are introduced into the support by impregnation. Sulfation is performed to obtain a catalyst precursor. The inorganic refractory oxide is selected from at least one of alumina, silicon oxide, titanium oxide and zirconium oxide. (2) Molecular sieves are introduced into the catalyst precursor, followed by drying and calcination. The content of the introduced molecular sieves is 1-12 wt% based on the total weight of the catalyst. The method for introducing molecular sieves into the catalyst precursor is at least one of the following: (a) The catalyst precursor and the molecular sieve precursor are subjected to hydrothermal treatment, and the drying and calcination described in step (2) are carried out under an inert atmosphere; (b) In the presence of a solvent, the catalyst precursor is mixed with the ball-milled molecular sieve, and then the drying and calcination described in step (2) are carried out. In steps (1) and (2), the molecular screening is selected from at least one of Y-type molecular sieve, ZSM-5 molecular sieve, β-type molecular sieve and MCM-41 molecular sieve; The amount of Group VIB and Group VIII metal salts used is such that, based on the total weight of the catalyst, the content of Group VIB metal sulfides as sulfides is 10-30 wt% and the content of Group VIII metal sulfides as sulfides is 2-10 wt%.

2. The preparation method according to claim 1, characterized in that, The impregnation in step (1) is either equal-volume impregnation or supersaturated impregnation.

3. The preparation method according to claim 1, characterized in that, In the mixed support formed in step (1), the molecular sieve accounts for 8-50% by weight.

4. The preparation method according to claim 3, characterized in that, In the mixed carrier formed in step (1), the molecular sieve accounts for 10-30% by weight.

5. The preparation method according to claim 4, characterized in that, In the mixed support formed in step (1), the molecular sieve accounts for 10-20% by weight.

6. The preparation method according to claim 1, characterized in that, After the impregnation in step (1) is completed, a drying process is also included, wherein the drying conditions include a temperature of 20-90°C and a time of 4-16 hours.

7. The preparation method according to claim 1, characterized in that, The amount of catalyst precursor and molecular sieve used in step (2) is such that the content of the subsequently introduced molecular sieve in the prepared catalyst is 1.5-8 wt% based on the total weight of the catalyst.

8. The preparation method according to claim 7, characterized in that, The content of the molecular sieve introduced in step (2) is 2-6 wt%.

9. The preparation method according to claim 1, characterized in that, In method (a), the molecular sieve precursor includes a silicon source or a silicon and aluminum source, which is mixed with a precipitant, a template agent and water to form a gel.

10. The preparation method according to claim 9, characterized in that, The silicon source is selected from at least one of sodium silicate, tetraethyl orthosilicate, silica sol, and silica gel for chromatography; the aluminum source is selected from at least one of sodium aluminate, aluminum hydroxide, and boehmite; the precipitant is selected from at least one of sodium hydroxide, ammonia, and potassium hydroxide; and the template agent is selected from at least one of hexadecyltrimethylammonium bromide, ethylenediamine, n-butylamine, tetrapropylammonium bromide, ethanol, tetraethylammonium hydroxide, tetraethylammonium bromide, triethylamine, di-n-propylamine, diisopropylamine, and methylcellulose.

11. The preparation method according to claim 9, characterized in that, When the molecular sieve is a silica-alumina molecular sieve, the molar composition of the gel is SiO2:Al2O3:Na2O:template:H2O = 5-30:1:1-10:1-10:100-300.

12. The preparation method according to claim 9, characterized in that, When the molecular sieve is an all-silica molecular sieve, the molar composition of the gel is SiO2: Na2O: template agent: H2O = 100: 10-30: 10-30: 1500-3000.

13. The preparation method according to claim 1, characterized in that, In method (a), the conditions for hydrothermal treatment include: a temperature of 90-200℃, a pressure of 0.1-2MPa, a pH of 7.5-9, and a time of 5-48 hours.

14. The preparation method according to claim 1, characterized in that, In method (b), the particle size of the ball-milled molecular sieve is 0.1-10 nm.

15. The preparation method according to claim 1, characterized in that, The drying conditions described in step (2) include a temperature of 20-90℃ and a time of 4-16 hours.

16. The preparation method according to claim 1, characterized in that, The roasting conditions in step (2) include: a temperature of 300-500℃ and a time of 2-5 hours.

17. The hydrocracking catalyst prepared by the preparation method according to any one of claims 1-16.

18. The application of the hydrocracking catalyst according to claim 17, used in the hydrocracking process of oil products.

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