CN116943712A

CN116943712A - Preparation method of vulcanized hydrocracking catalyst

Info

Publication number: CN116943712A
Application number: CN202210410262.XA
Authority: CN
Inventors: 李娟�; 徐学军; 王海涛; 翁肖一
Original assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2022-04-19
Filing date: 2022-04-19
Publication date: 2023-10-27

Abstract

The invention discloses a preparation method of a vulcanized hydrocracking catalyst, which comprises the following steps: (1) Mixing sodium molybdate and concentrated ammonia water until the sodium molybdate and the concentrated ammonia water are completely dissolved, heating the mixture to a reaction temperature, adding a vulcanizing agent for reaction, and carrying out solid-liquid separation on slurry after the reaction is finished to obtain a product M; (2) Dropwise adding the nickel salt alcohol solution into the polyvinylpyrrolidone alcohol solution, and performing solid-liquid separation after the dropwise adding is finished to obtain a product N; (3) Preparing a product M aqueous solution, preparing a product N alcohol solution, and introducing the M aqueous solution and an aluminum chloride solution into the N alcohol solution to carry out a gel forming reaction to obtain slurry; (4) Carrying out solid-liquid separation on the slurry, and removing sodium ions from the catalyst precursor; (5) And (3) vacuum drying the obtained filter cake, extruding and molding to obtain a molded product, and performing high-temperature annealing treatment to obtain the catalyst. The catalyst obtained by the method has good strength and pore structure, and is suitable for the hydrocracking process for producing special oil, lubricating oil base oil and middle distillate oil in maximum.

Description

Preparation method of vulcanized hydrocracking catalyst

Technical Field

The invention belongs to the field of catalyst preparation, and particularly relates to a preparation method of a high-activity high-selectivity vulcanized hydrocracking catalyst.

Background

The hydrocracking process can produce various high quality fuel and chemical materials, such as naphtha, diesel oil, aviation kerosene, lubricating oil base oil, special oil, etc., and can be flexibly adjusted according to market change. In order to adapt to the condition that the market demand of the finished oil is continuously reduced and is influenced by the whole economy at home and abroad at present, the hydrocracking process for producing the special oil with high added value becomes a popular choice. Compared with conventional hydrocracking products such as finished oil, chemical raw materials and the like, the quality index of the special oil is obviously different, and the special oil has very strict index requirements on low-temperature fluidity and aromatic hydrocarbon content, so that the hydrocracking catalyst is required to have high isomerism performance and high aromatic hydrocarbon conversion capability. The existing hydrocracking catalyst cannot give consideration to the low-temperature fluidity index and the aromatic hydrocarbon content index of the product, if the existing hydrocracking catalyst gives consideration to both the low-temperature fluidity index and the aromatic hydrocarbon content index, the high-isomerism molecular sieve is required to ensure the low-temperature fluidity index requirement of the special oil product of the diesel fraction, meanwhile, the limit amount limit of metal load of the existing preparation method of the hydrocracking catalyst is broken through, the loading amount of active metal is greatly increased, the hydrogenation performance of the catalyst is enhanced, the aromatic hydrocarbon saturation depth in the hydrocracking process is increased, the aromatic hydrocarbon content of the special oil product of the diesel fraction is reduced, and meanwhile, the viscosity index of the tail oil is improved.

The preparation method of the hydrocracking catalyst can be divided into an impregnation method, a kneading method, a beating method, an ion exchange method and a coprecipitation method, and the existing hydrocracking catalyst applied industrially adopts the impregnation method and the kneading method. The impregnation method has the advantages that the hydrogenation active center of the catalyst is arranged on the surface of a catalyst pore channel which can be accessed by reactant molecules, the utilization rate of the catalyst active metal is higher, the active metal content of the catalyst is limited by a carrier, the activity is difficult to be greatly improved, and the harsher hydrocracking reaction requirement cannot be met. The kneading rule is influenced by the molding difficulty, so that the hydrocracking catalyst with high metal content is difficult to obtain, meanwhile, due to the limitation of the preparation method, the components of the double-activity metal or multi-activity metal catalyst are difficult to mix uniformly, and the occurrence of the synergistic effect between the active metals cannot be effectively promoted, so that the active components of the catalyst are difficult to fully play the activity. Meanwhile, the catalyst prepared by adopting an impregnation method and a kneading method cannot use sodium-containing raw materials with relatively low price, so that the catalyst preparation cost is high and the wastewater treatment cost is high. And the coprecipitation method can be used for preparing sodium-containing raw materials with relatively low price, so that the preparation cost of the catalyst and the wastewater treatment cost are greatly reduced. However, due to the introduction of a large amount of sodium ions, the sodium ions in the catalyst are difficult to remove, only the sodium ions on the surface of the catalyst can be removed, a large amount of sodium ions still exist in the precipitated material, the residual sodium ions cause poor cohesiveness of the material and are difficult to form, and the sodium ions which are not removed are unfavorable for the formation of the pore channel structure of the catalyst, so that the pore volume and the pore diameter of the catalyst are smaller.

The catalyst prepared by the method is generally an oxidation type hydrocracking catalyst, and the catalyst can be used only by pre-vulcanizing in or out of a reactor. The complex process and equipment for pre-vulcanization and the pollution of the generated wastewater and waste gas to the environment are removed, and the pre-vulcanization process is difficult to achieve the expected effect on the currently prepared hydrocracking catalyst with high metal content, so that the activity of the catalyst is influenced.

CN106179467B discloses a sulfidic hydrocracking catalyst, which is a high metal bulk phase catalyst, and is obtained by adding sulfidic agent during kneading treatment after preparing oxidized active metal material by coprecipitation method, and subsequently performing heat treatment. The strong interaction between the oxide and the carrier in the material prepared in the middle and earlier stage of the catalyst can lead to incomplete vulcanization of the active metal of the catalyst and insufficient hydrogenation activity of the catalyst. CN103769197B, CN103769198B, CN103769199B, CN103769200B discloses a series of sulfided hydrocracking catalysts of the same type. For example, CN103769197B, which is a sulfided hydrocracking catalyst prepared by introducing molybdenum salt and/or tungsten salt solution, ammonium sulfide solution, nickel salt and/or cobalt salt into slurry with carrier component for reaction, and then drying under inert gas protection. The catalyst has high active metal content and high sulfidation degree, but the catalyst adopts inert gas protection during the drying treatment, and the molybdenum and tungsten in the reaction raw materials are Mo with high valence ⁶⁺ And W is ⁶⁺ The molybdenum and tungsten in the prepared vulcanized catalyst are mostly MoS ₃ And WS (WS) ₃ The molybdenum and tungsten exist in the form of tetravalent sulfide, and have better hydrogenation activity, so that the hydrogenation activity of active metals of the catalyst is not fully exerted although the catalyst is a high-metal sulfide type hydrocracking catalyst.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a preparation method of a vulcanized hydrocracking catalyst. The method adopts the sodium-containing raw material with lower price, combines the desalting treatment process of the catalyst precursor filter cake, obtains the catalyst with better strength and pore structure, eliminates the influence of impurity sodium element on the activity of the molecular sieve in the hydrocracking catalyst, and reduces the cost of the raw material of the catalyst.

The preparation method of the vulcanized hydrocracking catalyst comprises the following steps:

(1) Mixing sodium molybdate and concentrated ammonia water until the sodium molybdate and the concentrated ammonia water are completely dissolved, heating the mixture to a reaction temperature, adding a vulcanizing agent for reaction, and carrying out solid-liquid separation on slurry after the reaction is finished to obtain a product M;

(2) Respectively preparing polyvinylpyrrolidone (PVP) alcohol solution and nickel salt alcohol solution, dripping the nickel salt alcohol solution into the polyvinylpyrrolidone alcohol solution, and performing solid-liquid separation after dripping is finished to obtain a product N;

(3) Preparing a product M aqueous solution, preparing a product N alcohol solution, introducing the M aqueous solution and an aluminum chloride solution into the N alcohol solution, stirring at a high speed, simultaneously dripping a precipitator, and performing a gel forming reaction to obtain slurry;

(4) Filtering the slurry to obtain a filter cake, and preserving the filter cake; after the health preservation is finished, placing the filter cake in a vacuum filter, adding deionized water with a certain proportion a into the filter cake, and performing a vacuum filter process I until no suspension exists on the surface of the filter cake, and stopping the filter; continuing to add deionized water with a certain proportion b, and stopping suction filtration until no suspension exists on the surface of the filter cake in the suction filtration process II; adding deionized water with a certain proportion b again, and performing a pumping filtration process III until no filtrate is dripped down completely;

(5) And (3) carrying out vacuum drying on the obtained filter cake after removing impurities, kneading, extruding and molding the dried material, the molecular sieve and the molding auxiliary agent to obtain a molded product, and carrying out high-temperature annealing treatment to obtain the vulcanized hydrocracking catalyst.

In the method, the proportion of the sodium molybdate to the concentrated ammonia water in the step (1) is 200-600 g/L; the concentration range of the concentrated ammonia water is 25-28 wt%.

In the method, the vulcanizing agent in the step (1) is an ammonium sulfide aqueous solution with the weight percent of 20-25% or an ammonium thiosulfate aqueous solution with the weight percent of 50-60%; the ratio of the sodium molybdate to the ammonium sulfide aqueous solution is 150-600 g/L; the ratio of the sodium molybdate to the ammonium thiosulfate aqueous solution is 150-600 g/L.

In the method, the reaction temperature in the step (1) is 55-80 ℃, preferably 60-70 ℃; the reaction time is 1 to 3 hours, preferably 2 to 2.5 hours.

In the method of the present invention, the average molecular weight of PVP in step (2) is 3000-60000, such as model K12, K15, K17, K25 or K30, preferably 45000-58000, preferably model K30. The nickel salt is soluble nickel salt, such as one or more of nickel nitrate, nickel acetate or nickel chloride; the alcohol solvent is one or more of ethanol, ethylene glycol, propylene glycol, glycerol or isopropanol.

In the method, in the step (2), the mass ratio of the nickel salt alcohol solution to the PVP alcohol solution is 1:1-3, and the mass concentration of the nickel salt alcohol solution is 20-100 g/L, preferably 30-50 g/L; the mass concentration of the PVP alcohol solution is 30-100 g/L, preferably 80-100 g/L.

In the method, the reaction temperature in the step (2) is 50-100 ℃, preferably 60-75 ℃; the reaction time is 1.5-8 hours.

In the method of the invention, the alcohol solvent in the step (3) is one or more of ethanol, ethylene glycol, propylene glycol, glycerol or isopropanol.

In the method, the mass concentration of the product M aqueous solution in the step (3) is 5-20 g/L, the mass concentration of the product N alcohol solution is 1-5 g/L, and the volume ratio of the M aqueous solution to the N alcohol solution is 1:3 to 10, preferably 1:4 to 6.

In the method, the mass concentration of the aluminum chloride solution in the step (3) is 8-15 g/L, and the content of aluminum oxide is generally 15-65 wt% based on the final catalyst mass.

In the method, the precipitant in the step (3) is sodium hydroxide solution and/or sodium bicarbonate solution, and the mass percentage concentration of the precipitant is 5-20wt%; in the gelling reaction, controlling the acceleration of alkali liquid drops, dripping for 15-120 min, measuring the pH of the reaction solution on line, and ending the reaction when the pH of the reaction solution is 6.5-7.5.

In the method of the invention, the health maintenance process in the step (4) is as follows: the humidity of the filter cake health-preserving environment is more than 75%; the curing temperature is 20-50 ℃, preferably 30-35 ℃; the curing time is 0.5-2 hours, preferably 1-1.5 hours; the health preserving process can be carried out in any environment meeting the conditions, preferably directly carried out in vacuum filtration equipment, the filter cake is not moved, and the operation flow is simplified.

In the method of the invention, after the health maintenance process in the step (4) is finished: the water content of the filter cake is kept at 70% -95%, preferably 80% -85%; the curing process causes part of hydrated sodium ions in the filter cake to separate out from the precursor and reserve vacancies, and the pore volume of the catalyst precursor is increased and has good mechanical strength.

In the method, deionized water with a certain proportion a in the step (4) is used as a catalyst, and the mass ratio of the deionized water to the catalyst is 1:0.5-2, preferably 1:1; the deionized water with a certain proportion b is as follows: the mass ratio of the catalyst to deionized water is 1:4-15, preferably 1:5-9.

In the method of the invention, the suction filtration process I, II and III in the step (4): deionized water cannot be stirred with the filter cake, and vacuum filtration is started within 5 minutes, preferably within 1 minute after adding deionized water.

In the method, the vacuum drying temperature in the step (5) is 50-90 ℃, preferably 60-70 ℃; the dry basis of the drying is controlled to be 40-70 wt%, preferably 45-60 wt%.

In the method of the invention, the molecular sieve in the step (5) is one or more of a Y-type molecular sieve, a beta-molecular sieve, an MCM-41 mesoporous molecular sieve, a SAPO molecular sieve, a ZSM-5 molecular sieve and the like, and preferably the beta-molecular sieve. The molecular sieve content is typically 5wt% to 40wt% based on the final catalyst weight.

In the method, the forming auxiliary agent in the step (5) is a use auxiliary agent which is conventionally adopted in the field, the peptizing agent is one or more of nitric acid, acetic acid, hydrochloric acid, oxalic acid and sulfuric acid, and the dosage of the forming auxiliary agent is 3-12 wt% of the mass of the extruded material based on the mass of the extruded material; the extrusion molding extrusion assisting agent is one or more of sesbania powder, carbon black, graphite powder and the like, and the consumption is 5-15 wt% of the mass of the extrusion material based on the mass of the extrusion material, preferably 7-8 wt%.

In the method, the high-temperature annealing treatment in the step (5) is performed in an atmosphere containing hydrogen, wherein the atmosphere containing hydrogen is hydrogen or a mixed atmosphere of hydrogen and an inert atmosphere; the inert atmosphere is one or more of nitrogen and inert gas, preferably hydrogen and nitrogen are combined, and the proportion of the hydrogen in the gas is not less than 40mol%; the annealing temperature is 300-550 ℃, preferably 400-500 ℃; the annealing time is 3-8 hours.

The invention also provides a sulfuration type hydrocracking catalyst, which comprises molybdenum sulfide, nickel sulfide, molecular sieve and alumina; wherein the atomic mole ratio of the metallic molybdenum to the metallic nickel is 1-5:1-3, preferably 1-2:1; based on the weight of the catalyst, the mass fraction of the sulfide of the molybdenum and the sulfide of the nickel accounts for 30-80 wt% of the catalyst, and is preferably 55-70 wt%; the molecular sieve is 5-40 wt%, preferably 8-20 wt%; 15-65 wt% of aluminum oxide; the sodium content is no more than 0.1 percent.

Wherein the sulfide of molybdenum and the sulfide of nickel are generally expressed in MoS ₂ In the form of NiS, small amounts of molybdenum may be present in the form of MoS ₃ In the form of a gel.

The specific surface area of the vulcanized hydrocracking catalyst is 250-600 m ² Per gram, the pore volume is 0.30-0.50 mL/g, and the catalyst strength is 15.0-25.0N.mm ^-1 。

The method of the invention uses clean, environment-friendly and low-cost sodium-containing raw materials to prepare the catalyst, the catalyst precursor generated by the coprecipitation reaction contains a large amount of sodium ions, and in the coprecipitation process, active metal molybdenum and nickel which are vulcanized in advance are caused to react in the sodium ionsA stable structure (Ni ²⁺ +MoS ₄ ^2- →Ni-MoS ₄ Molybdenum is Mo ⁶⁺ Form present).

The method directly removes sodium ions as impurities from the catalyst precursor, and has simple flow and high impurity removal efficiency; the method washes the precursor in a short time after the preparation of the precursor, reduces the adsorption degree of sodium ions to the catalyst increased by the post-drying and strip extrusion treatment, and is easier to remove; meanwhile, compared with the traditional pulping washing, the method can carry away a large amount of aqueous solution containing sodium impurity in the precursor filter cake through a small amount of water in the health preserving and vacuum filtration washing, thereby meeting the requirement that the sodium content in the catalyst precursor is not more than 0.1%, realizing the reduction of washing times and greatly reducing the water consumption in the catalyst preparation process. The inventor carries out vacuum drying on the catalyst precursor without impurity sodium, and the pore expansion effect of the precursor is obvious. The moisture in the precursor is rapidly diffused outwards in a water vapor mode in the vacuum drying process, so that the pore channel structure of the precursor is impacted, the internal pore channel of the precursor is enlarged, the pore distribution moves to the direction of a large pore, and the pore volume and the pore diameter of the catalyst are increased; meanwhile, as the impurity sodium is removed, sodium chloride crystals are not precipitated in the drying process and attached to the inner pore canal of the precursor to affect reaming, so that the reaming effect in the drying process is more obvious than that of removing the impurity sodium after the catalyst is molded.

And sodium impurity in the catalyst precursor is removed, so that the problems that the catalyst is difficult to form after the catalyst is formed and the strength is smaller after the catalyst is formed are solved.

The following reduction reactions occur during the subsequent high temperature annealing of the invention: ni-MoS ₄ +H ₂ →Ni-MoS ₃ +H ₂ S (molybdenum is reduced to Mo) ⁴⁺ Has higher hydrogenation activity), the active metal before annealing is in a vulcanized form, and strong interaction generated by the formation of Mo-O-Al bridging bond between the oxidized active metal and the carrier at high temperature does not exist, so that the interaction between the active metal and the carrier is weak, and the second active component Ni can be well controlled in MoS ₂ Resulting in less active ingredient entering the support phase and thus in the catalyst preparedThe Ni-Mo-S phase of the catalyst is mainly a II-type Ni-Mo-S active phase with weaker interaction with the carrier, so that the atom utilization rate of the active metal component of the catalyst is higher, and the hydrogenation saturation activity and selectivity of the catalyst are greatly improved compared with those of the similar catalyst. The PVP remained in the catalyst precursor can be burnt in the annealing process, so that the diffusion performance of the catalyst is further improved, and the problem of small catalyst pore volume in the process of improving the metal content in the cracking catalyst in the prior art is solved.

The catalyst has high sulfuration degree, active metal directly forms sulfide of molybdenum and nickel through a gelling reaction during preparation, and compared with a sulfuration type hydrocracking catalyst which is formed by adding a sulfuration agent to bake after the gelling reaction and an oxidation type hydrocracking catalyst which is formed by performing catalyst presulfiding through in-device sulfuration, the catalyst has the advantages of complete sulfuration of the active metal in the catalyst, high utilization rate of the active metal of the catalyst and high hydrogenation activity of the catalyst. The sulfuration type hydrocracking catalyst does not need to be presulfided in a reactor before use, links such as nitrogen drying and in-reactor sulfuration in the starting process are omitted, the starting time is effectively saved, and no sulfur acid wastewater and waste gas are discharged. The starting process is simple and environment-friendly, and the safety and environment-friendly pressure of the oil refining enterprise in the device starting process is relieved.

The vulcanized hydrocracking catalyst can be used for the hydrocracking process for producing special oil, lubricating oil base oil and middle distillate oil in maximum, and is particularly suitable for the hydrocracking process for producing transformer oil, white oil and high-viscosity index lubricating oil base oil raw materials.

Detailed Description

The technical solutions of the present invention will be clearly and completely described in conjunction with specific embodiments of the present invention, and it is apparent that the described embodiments are only some embodiments of the present invention, but not all embodiments. PVP used in the following examples and comparative examples was produced by the national pharmaceutical group chemical Co., ltd. Model K30 and produced by the Meinai Biotechnology Co., ltd. Model K15. The catalyst test characterization method adopts Agilent inductively coupled plasma mass spectrometer (7700 ICP-MS) to perform element analysis; measuring the phase structure and crystal form of the catalyst on a D/MAX-2500X-ray diffractometer of Japanese light management; the specific surface area and pore size distribution of the support were measured on an ASAP-2405 BET nitrogen adsorber in the United states; measuring the catalyst crush strength on a particle strength tester; molecular sieve acidity was measured on a Nicolet 6700 fourier transform infrared spectrometer.

Example 1

Mutually dissolving sodium molybdate and 28wt% concentration ammonia water at the temperature of 40 ℃ in the proportion of 250g/L, adding 20wt% concentration vulcanized ammonia water solution based on the mass of sodium molybdate, adding 5mL/g sodium molybdate, reacting for 2 hours at the temperature of 65 ℃, and filtering the slurry to obtain a product M;

preparing an absolute ethyl alcohol solution of PVP (K30) with the concentration of 80g/L, preparing an absolute ethyl alcohol solution of nickel acetate with the concentration of 40g/L, dropwise adding the nickel acetate solution into the PVP solution at the temperature of 68 ℃ in the ratio of 1:1 for 30min, continuously stirring for reacting for 2h, and filtering the slurry to obtain a product N;

preparing an M aqueous solution with the concentration of 15g/L, preparing an N isopropanol solution with the concentration of 2g/L, preparing an aluminum chloride solution with the concentration of 10g/L, introducing the M solution and the aluminum chloride solution into the N solution, and stirring at a high speed, wherein the volume ratio of the M, N solution is M: n=1: 4, adding the aluminum chloride solution in an amount of 15% of the total mass of the catalyst by final alumina, dropwise adding sodium bicarbonate solution with the concentration of 20wt%, controlling the pH value to be 7.5, and dropwise adding for 30min to obtain slurry;

vacuum filtering the slurry to obtain a catalyst precursor filter cake; the filter cake is subjected to health maintenance, the health maintenance is directly carried out in a vacuum filter, the humidity of the health maintenance environment is kept at 80%, the health maintenance temperature is 30 ℃ and the time is 1.0h, and the filter cake with the water content of 82% is obtained after the health maintenance is finished; adding the catalyst into a filter cake of a vacuum filter to prepare a catalyst, wherein the mass ratio of the catalyst to the filter cake is 1:1, carrying out vacuum suction filtration on the deionized water after 20S until no suspension exists on the surface of a filter cake; continuously adding the catalyst into the filter cake to prepare the catalyst with the mass ratio of 1:5, deionized water, and carrying out vacuum suction filtration after 20S until no suspension exists on the surface of the filter cake; and adding deionized water with the same mass into the filter cake again, carrying out vacuum suction filtration after 20S until the filter cake completely has no filtrate dripping, and finishing washing.

Vacuum drying at 70 ℃ to control the dry basis to be 50%; rolling and extruding the mixture into clover-shaped catalyst based on the final catalyst mass according to the mass ratio of the beta molecular sieve (the property of the beta molecular sieve is shown in Table 3) to other components of 1:5. And (3) carrying out annealing treatment on the formed strip, wherein the annealing atmosphere is hydrogen, the heating process is 3 ℃/min in the annealing process, constant-temperature annealing is carried out after the temperature is raised to 380 ℃, the annealing time is 3h, and the final catalyst a is obtained, and the main properties are shown in Table 1.

Example 2

Mutually dissolving sodium molybdate and 28wt% concentration ammonia water at a ratio of 600g/L and 50 ℃, adding 20wt% concentration vulcanized ammonia water solution based on the mass of sodium molybdate, adding 3mL/g sodium molybdate, reacting at 75 ℃ for 1.5h, and filtering the slurry to obtain a product M;

preparing an isopropyl alcohol solution of PVP (K15) with the concentration of 100g/L, preparing an isopropyl alcohol solution of nickel chloride with the concentration of 60g/L, dropwise adding the nickel acetate solution into the PVP solution at the temperature of 80 ℃ in the ratio of 1:2 for 30min, continuously stirring for reaction for 6h, and filtering the slurry to obtain a product N;

preparing an M aqueous solution with the concentration of 7g/L, preparing an N isopropanol solution with the concentration of 1g/L, preparing an aluminum chloride solution with the concentration of 8g/L, introducing the M solution and the aluminum chloride solution into the N solution, and stirring at a high speed, wherein the volume ratio of the M, N solution is M: n=1: 6, adding the aluminum chloride solution in an amount of 30% of the total mass of the catalyst by final alumina, dropwise adding 10wt% sodium hydroxide solution, controlling the pH value to be 7.0, and dropwise adding for 40 min to obtain slurry;

vacuum filtering the slurry to obtain a catalyst precursor filter cake; the filter cake is subjected to health maintenance, the health maintenance is directly carried out in a vacuum filter, the humidity of the health maintenance environment is kept at 85%, the health maintenance temperature is 40 ℃ and the time is 2.0h, and the filter cake with the water content of 78% is obtained after the health maintenance is finished; adding the catalyst into a filter cake of a vacuum filter to prepare a catalyst, wherein the mass ratio of the catalyst to the filter cake is 1:2, deionized water, and carrying out vacuum suction filtration after 1.5min until no suspension exists on the surface of the filter cake; continuously adding the catalyst into the filter cake to prepare the catalyst with the mass ratio of 1:4, deionized water, and carrying out vacuum suction filtration after 2min until no suspension exists on the surface of the filter cake; and adding deionized water with the same mass into the filter cake again, carrying out vacuum suction filtration after 2min until the filter cake completely has no filtrate dripping, and finishing washing.

Vacuum drying at 85 ℃ to control 65wt% of dry basis; and rolling and extruding strips to form (clover) according to the mass ratio of the beta molecular sieve to other components of 1:4 by taking the mass of the final catalyst as a reference. And (3) carrying out annealing treatment on the forming strip, wherein the annealing atmosphere is a combination of hydrogen and nitrogen, the hydrogen accounts for 60mol%, the heating process in the annealing process is 3 ℃/min, the constant-temperature annealing is carried out after the temperature is raised to 450 ℃, and the annealing time is 7 hours, so that the final catalyst b is obtained, and the main properties are shown in Table 1.

Example 3

Mutually dissolving sodium molybdate and 28wt% concentration ammonia water at the temperature of 35 ℃ in the proportion of 450g/L, adding 55wt% concentration ammonium thiosulfate aqueous solution based on the mass of sodium molybdate, adding 4mL/g sodium molybdate, reacting for 3 hours at 58 ℃, and filtering the slurry to obtain a product M;

preparing an ethanol solution of PVP (K30) with the concentration of 40g/L, preparing an ethanol solution of nickel nitrate with the concentration of 90g/L, dropwise adding the nickel acetate solution into the PVP solution at the temperature of 60 ℃ in the ratio of 1:3 for 30min, continuously stirring for reacting for 4h, and filtering the slurry to obtain a product N;

preparing an M aqueous solution with the concentration of 20g/L, preparing an ethanol solution with the concentration of 3.5g/L of N, preparing an aluminum chloride solution with the concentration of 15g/L, introducing the M solution and the aluminum chloride solution into the N solution, and stirring at a high speed, wherein the volume ratio of the M, N solution is M: n=1: 8, adding the aluminum chloride solution in an amount of 45% of the total mass of the catalyst by final alumina, dropwise adding mixed solution of sodium bicarbonate with the concentration of 10wt% and sodium hydroxide with the concentration of 5wt% respectively, controlling the pH at 7.5, and dropwise adding for 60min to obtain slurry;

vacuum filtering the slurry to obtain a catalyst precursor filter cake; the filter cake is subjected to health maintenance, the filter cake is placed in an insulation box for health maintenance, the humidity of the health maintenance environment is kept at 90%, the health maintenance temperature is 45 ℃ and the time is 0.5h, and the filter cake with the water content of 90% is obtained after the health maintenance is finished; putting the filter cake on the filter cloth of a vacuum suction filter in a flat and seamless way, and adding a catalyst into the filter cake to prepare the catalyst with the mass ratio of 1:0.7 of deionized water, and carrying out vacuum suction filtration after 1min until no suspension exists on the surface of the filter cake; continuously adding the catalyst into the filter cake to prepare the catalyst with the mass ratio of 1:9, deionized water, and vacuum filtering after 1min until no suspension exists on the surface of the filter cake; adding deionized water with equal mass into the filter cake again, carrying out vacuum suction filtration after 1min until the filter cake completely has no filtrate dripping, and finishing washing.

Vacuum drying at 60 ℃ to control 45wt% of dry basis; rolling and extruding strips to form the catalyst based on the final catalyst mass according to the mass ratio of the Y-type molecular sieve (the property of the Y molecular sieve is shown in Table 4) to other components of 1:6. And (3) carrying out annealing treatment on the forming strip, wherein the annealing atmosphere is a combination of hydrogen and helium, the hydrogen accounts for 50mol%, the heating process in the annealing process is 3 ℃/min, the constant-temperature annealing is carried out after the temperature is raised to 500 ℃, and the annealing time is 5h, so that the final catalyst c is obtained, and the main properties are shown in Table 1.

Example 4

Mutually dissolving sodium molybdate and concentrated ammonia water with the concentration of 25wt% at the temperature of 45 ℃ in the proportion of 500g/L, adding an ammonium thiosulfate aqueous solution with the concentration of 60wt% based on the mass of the sodium molybdate, reacting for 2.5 hours at the temperature of 70 ℃ with the addition of 2mL/g sodium molybdate, and filtering the slurry to obtain a product M;

preparing an ethanol solution of PVP (K30) with the concentration of 60g/L, preparing an ethanol solution of nickel acetate with the concentration of 50g/L, dropwise adding the nickel acetate solution into the PVP solution at the temperature of 75 ℃ in the ratio of 1:2 for 30min, continuously stirring for reacting for 3h, and filtering the slurry to obtain a product N;

preparing an M aqueous solution with the concentration of 12g/L, preparing an ethanol solution with the concentration of 2.5g/L of N, preparing an aluminum chloride solution with the concentration of 12g/L, introducing the M solution and the aluminum chloride solution into the N solution, and stirring at a high speed, wherein the volume ratio of the M, N solution is M: n=1: 3, adding the aluminum chloride solution in an amount of 20% of the total mass of the catalyst by final alumina, dropwise adding mixed solution of sodium bicarbonate with the concentration of 10% and sodium hydroxide with the concentration of 10% respectively, controlling the pH value at 7.5, and dropwise adding for 100min to obtain slurry.

Vacuum filtering the slurry to obtain a catalyst precursor filter cake; the filter cake is subjected to health maintenance, the health maintenance is directly carried out in a vacuum filter, the humidity of the health maintenance environment is kept at 75%, the health maintenance temperature is 25 ℃ and the time is 1.0h, and the filter cake with the water content of 88% is obtained after the health maintenance is finished; adding the catalyst into a filter cake of a vacuum filter to prepare a catalyst, wherein the mass ratio of the catalyst to the filter cake is 1:1.4, carrying out vacuum suction filtration after 5min until no suspension exists on the surface of the filter cake; continuously adding the catalyst into the filter cake to prepare the catalyst with the mass ratio of 1:12, carrying out vacuum suction filtration until no suspension exists on the surface of the filter cake after 5 min; and adding deionized water with the same mass into the filter cake again, carrying out vacuum suction filtration after 5min until the filter cake completely has no filtrate dripping, and finishing washing.

Vacuum drying at 65 ℃ to control 55wt% of dry basis; and rolling and extruding strips to form (clover) according to the mass ratio of the Y-type molecular sieve to other components of 1:3 by taking the mass of the final catalyst as a reference. And (3) carrying out annealing treatment on the forming strip, wherein the annealing atmosphere is a combination of hydrogen and helium, the hydrogen accounts for 50mol%, the heating process in the annealing process is 3 ℃/min, the constant-temperature annealing is carried out after the temperature is raised to 400 ℃, the annealing time is 6h, and the final catalyst d is obtained, and the main properties are shown in Table 1.

Comparative example 1

centrifuging the slurry to obtain a catalyst precursor, and vacuum drying at 70 ℃ to control the dry basis to be 50%; rolling and extruding the mixture into clover-shaped catalyst based on the final catalyst mass according to the mass ratio of the beta molecular sieve (the property of the beta molecular sieve is shown in table 4) to other components of 1:5. Curing the molded strips, wherein the temperature of the first stage is 80 ℃ and the time is 45 hours; the second stage is carried out at 28 ℃ for 30 hours; washing with deionized water for 3 times, wherein the mass ratio of water to catalyst preparation is 1:12; the washed wet strips were then dried in vacuo at 70℃for 10 hours. And (3) annealing the dried strip, wherein the annealing atmosphere is hydrogen, the heating process in the annealing process is 3 ℃/min, and the constant-temperature annealing is performed after the temperature is raised to 380 ℃ for 3 hours. The final catalyst m was obtained with the composition, main properties and pore distribution shown in Table 1.

Comparative example 2

The other steps of this example were identical to those of example 1, except that the impurity removal process in step 4 of this comparative example was carried out by directly adding deionized water without maintaining the health for suction filtration. The final catalyst n was obtained and the main properties are shown in Table 1.

Comparative example 3

The other steps of this example are the same as those of example 1, except that in the impurity removal process of step 4, the catalyst is directly added after the health maintenance in the mass ratio of 1:11, deionized water. The final catalyst o was obtained and the main properties are shown in Table 1.

Comparative example 4

Other steps of this example were the same as those of example 3 except that the comparative example was conducted under a nitrogen atmosphere when the dried bars were annealed, the temperature raising process was 3 ℃/min during the annealing, and the constant temperature annealing was conducted after the temperature was raised to 400 ℃ for 6 hours. The final catalyst p was obtained and the main properties are shown in Table 1.

Comparative example 5

The preparation method disclosed by CN106179467A comprises the following specific steps:

respectively dissolving nickel chloride and aluminum chloride solution in purified water to prepare a mixed solution A, wherein the weight concentration of NiO in the mixed solution A is 23g/L, and Al ₂ O ₃ The weight concentration of the solution is 5g/L, respectively dissolving ammonium metatungstate and aluminum chloride solution in purified water, adding dilute water glass solution to prepare a mixed solution B, and adding WO into the mixed solution B ₃ The weight concentration of (C) is 20g/L, al ₂ O ₃ The weight concentration of (C) is 18g/L, siO ₂ The weight concentration of (C) is 30g/L. Adding 10% ammonia water into the solution A under stirring, maintaining the gel forming temperature at 55deg.C, controlling pH value at 7.6 at the end, and controlling gel forming time at 60min to obtain precipitate slurry I containing nickel and aluminum. 1000mL of purified water was added to the reaction tank, and 10% strength ammonia water and solution B were added in parallel to the reaction tankIn the process, the gelatinization temperature is kept at 55 ℃, the pH value is controlled at 7.6 in the parallel flow gelatinization reaction process, and the gelatinization time is controlled at 60 minutes, so that the precipitate slurry II containing tungsten, silicon and aluminum is generated. Mixing the two precipitate-containing slurries, aging for 2 hours at 75 ℃, controlling the pH value at 7.6 after aging, filtering, and performing hydrothermal treatment on the filter cake under the water vapor containing urea, wherein the conditions of the hydrothermal treatment are as follows: the molar ratio of urea to the total amount of active metal atoms is 6:1, the temperature is 230 ℃, the pressure is 4.5MPa, the treatment time is 4 hours, the filter cake is pulped after the treatment, Y-type molecular sieve suspension accounting for 10 weight percent of the catalyst is added into the mixture slurry based on dry basis, the mixture slurry is uniformly dispersed into the mixture slurry, the mixture slurry is filtered, washed 3 times with water, dried at 100 ℃ for 8 hours, and the mixture is rolled after materials, ammonium thiosulfate (the adding amount of the ammonium thiosulfate is 120 percent of the theoretical sulfur requirement of the catalyst based on the sulfur element) and dodecene (the adding amount of the dodecene accounts for 10 percent of the weight of the materials) are mixed, extruded and formed. Drying at 80℃for 10 hours. The heat treatment is carried out in the presence of hydrogen, and the temperature is kept at 450 ℃ for 4 hours, so as to obtain the catalyst q. The main properties of the catalyst are shown in Table 1.

Example 5

This example is an evaluation experiment of the activity of the catalyst of the present invention and is compared with a comparative catalyst. Comparative evaluation tests were performed on a 200mL small hydrogenation unit using the catalyst of the invention a, b, c, d and the catalyst of comparative example m, n, o, p, q.

The evaluation conditions were: the total reaction pressure is 14.7MPa, and the hydrogen-oil volume ratio is 1200:1, liquid hourly space velocity 1.5h ^-1 The reaction temperature was 380℃and the main properties of the raw materials for evaluation are shown in Table 4, and the results of the catalyst evaluation are shown in Table 6.

From the evaluation results table 5, the hydrocracking activity of the catalyst a, b, c, d prepared by the method is superior to that of comparative example q, which shows that the catalyst prepared by the method has high active metal content, high catalyst vulcanization degree and good catalyst pore distribution, and is mainly concentrated in macropores, so that the hydrocracking reaction activity of the catalyst is obviously improved. The hydrocracking activity of the catalyst a is superior to that of comparative examples m, n and o, which shows that the catalyst a has good sodium removal effect on the catalyst precursor and plays a role in promoting the catalyst activity. The hydrocracking activity of catalyst c was superior to comparative example p, indicating that the annealing treatment in the process of the present invention promotes catalyst activity.

Table 1 catalyst compositions and properties prepared in examples and comparative examples

Table 2 properties of beta molecular sieves in examples and comparative examples

Table 3 properties of Y-type molecular sieves in examples and comparative examples

TABLE 4 Properties of raw oil

TABLE 5 evaluation results of catalysts

Claims

1. The preparation method of the vulcanized hydrocracking catalyst is characterized by comprising the following steps: (1) Mixing sodium molybdate and concentrated ammonia water until the sodium molybdate and the concentrated ammonia water are completely dissolved, heating the mixture to a reaction temperature, adding a vulcanizing agent for reaction, and carrying out solid-liquid separation on slurry after the reaction is finished to obtain a product M; (2) Respectively preparing a polyvinylpyrrolidone alcohol solution and a nickel salt alcohol solution, dripping the nickel salt alcohol solution into the polyvinylpyrrolidone alcohol solution, and carrying out solid-liquid separation after dripping is finished to obtain a product N; (3) Preparing a product M aqueous solution, preparing a product N alcohol solution, introducing the M aqueous solution and an aluminum chloride solution into the N alcohol solution, stirring at a high speed, simultaneously dripping a precipitator, and performing a gel forming reaction to obtain slurry; (4) Filtering the slurry to obtain a filter cake, and preserving the filter cake; after the health preservation is finished, placing the filter cake in a vacuum filter, adding deionized water with a certain proportion a into the filter cake, and performing a vacuum filter process I until no suspension exists on the surface of the filter cake, and stopping the filter; continuing to add deionized water with a certain proportion b, and stopping suction filtration until no suspension exists on the surface of the filter cake in the suction filtration process II; adding deionized water with a certain proportion b again, and performing a pumping filtration process III until no filtrate is dripped down completely; (5) And (3) carrying out vacuum drying on the obtained filter cake after removing impurities, kneading, extruding and molding the dried material, the molecular sieve and the molding auxiliary agent to obtain a molded product, and carrying out high-temperature annealing treatment to obtain the vulcanized hydrocracking catalyst.

2. The method according to claim 1, characterized in that: the proportion of the sodium molybdate to the concentrated ammonia water in the step (1) is 200-600 g/L; the concentration range of the concentrated ammonia water is 25-28 wt%.

3. The method according to claim 1, characterized in that: the vulcanizing agent in the step (1) is an ammonium sulfide aqueous solution with the weight percent of 20-25% or an ammonium thiosulfate aqueous solution with the weight percent of 50-60%; the ratio of the sodium molybdate to the ammonium sulfide aqueous solution is 150-600 g/L; the ratio of the sodium molybdate to the ammonium thiosulfate aqueous solution is 150-600 g/L.

4. The method according to claim 1, characterized in that: the reaction temperature in the step (1) is 55-80 ℃ and the reaction time is 1-3 hours.

5. The method according to claim 1, characterized in that: the molecular weight of polyvinylpyrrolidone in the step (2) ranges from 3000 to 60000; the nickel salt is soluble nickel salt, and is selected from one or more of nickel nitrate, nickel acetate or nickel chloride; the alcohol solvent is one or more of ethanol, ethylene glycol, propylene glycol, glycerol or isopropanol.

6. The method according to claim 1, characterized in that: in the dropwise adding process, the mass ratio of the nickel salt alcohol solution to the polyvinylpyrrolidone alcohol solution is 1:1-3, and the mass concentration of the nickel salt alcohol solution is 20-100 g/L; the mass concentration of the polyvinylpyrrolidone alcohol solution is 30-100 g/L.

7. The method according to claim 1, characterized in that: the reaction temperature in the step (2) is 50-100 ℃ and the reaction time is 1.5-8 hours.

8. The method according to claim 1, characterized in that: the alcohol solvent in the step (3) is one or more of ethanol, ethylene glycol, propylene glycol, glycerol or isopropanol.

9. The method according to claim 1, characterized in that: in the step (3), the mass concentration of the product M aqueous solution is 5-20 g/L, the mass concentration of the product N alcohol solution is 1-5 g/L, and the volume ratio of the M aqueous solution to the N alcohol solution is 1: 3-10.

10. The method according to claim 1, characterized in that: the mass concentration of the aluminum chloride solution in the step (3) is 8-15 g/L, the adding amount of the aluminum chloride solution is 15-65 wt% based on the mass of the final catalyst.

11. The method according to claim 1, characterized in that: the precipitant in the step (3) is sodium hydroxide solution and/or sodium bicarbonate solution, and the mass percentage concentration of the precipitant is 5-20wt%; in the gelling reaction, controlling the acceleration of alkali liquid drops, dripping for 15-120 min, measuring the pH of the reaction solution on line, and ending the reaction when the pH of the reaction solution is 6.5-7.5.

12. The method according to claim 1, characterized in that: the health preserving process comprises the following steps: the humidity of the filter cake health-preserving environment is more than 75%; the curing temperature is 20-50 ℃ and the curing time is 0.5-2 hours; after the health preserving process is finished: the water content of the filter cake is kept at 70% -95%.

13. The method according to claim 1, characterized in that: the deionized water with a certain proportion a is added according to the mass ratio of the catalyst preparation mass to the deionized water of 1:0.5-2; and the certain proportion b is added according to the mass ratio of the catalyst preparation mass to the deionized water of 1:4-15.

14. The method according to claim 1, characterized in that: and (3) the suction filtration processes I, II and III in the step (4): deionized water can not be stirred with the filter cake, and vacuum filtration is started within 5 minutes after the deionized water is added.

15. The method according to claim 1, characterized in that: the vacuum drying temperature in the step (5) is 50-90 ℃; the dry basis of the drying is controlled to be 40-70 wt%.

16. The method according to claim 1, characterized in that: the molecular sieve in the step (5) is one or more of a Y-type molecular sieve, a beta-type molecular sieve, an MCM-41 mesoporous molecular sieve, a SAPO molecular sieve, a ZSM-5 molecular sieve and the like, and the content of the molecular sieve is 5-40 wt% based on the weight of the final catalyst.

17. The method according to claim 1, characterized in that: the forming auxiliary agent in the step (5) is a using auxiliary agent which is conventionally adopted in the field, the peptizing agent is one or more of nitric acid, acetic acid, hydrochloric acid, oxalic acid and sulfuric acid, and the dosage of the forming auxiliary agent is 3-12 wt% of the mass of the extruded material based on the mass of the extruded material; the extrusion molding extrusion assisting agent is one or more of sesbania powder, carbon black, graphite powder and the like, and the consumption is 5-15 wt% of the mass of the extrusion material based on the mass of the extrusion material, preferably 7-8 wt%.

18. The method according to claim 1, characterized in that: the high-temperature annealing treatment in the step (5) is carried out in an atmosphere containing hydrogen, wherein the atmosphere containing hydrogen is hydrogen or a mixed atmosphere of hydrogen and inert atmosphere; the inert atmosphere is one or more of nitrogen or inert gas; the proportion of the hydrogen in the gas is not less than 40mol%; the annealing temperature is 300-550 ℃, and the annealing time is 3-8 hours.

19. The sulfided hydrocracking catalyst prepared by any one of claims 1 to 18, which is characterized in that: catalysts include molybdenum sulfides, nickel sulfides, molecular sieves, and alumina; wherein the atomic mole ratio of the metallic molybdenum to the metallic nickel is 1-5:1-3; based on the weight of the catalyst, the mass fraction of the sulfide of the molybdenum and the sulfide of the nickel accounts for 30-80 wt% of the catalyst; the molecular sieve accounts for 5-40 wt%; 15-65 wt% of aluminum oxide; sodium content no more than 0.1%; specific surface area of the vulcanized hydrocracking catalyst is 250-600 m ² Per gram, the pore volume is 0.30-0.50 mL/g, and the catalyst strength is 15.0-25.0N.mm ^-1 。

20. The use of a sulfided hydrocracking catalyst prepared according to any one of claims 1 to 18 in a hydrocracking process for producing specialty oils, lube base oils and maximally middle distillates.