CN109926075B

CN109926075B - High-activity hydrotreating catalyst and preparation method thereof

Info

Publication number: CN109926075B
Application number: CN201711349773.0A
Authority: CN
Inventors: 金浩; 朱慧红; 葛海龙; 孟兆会; 杨光; 孙素华; 杨涛
Original assignee: China Petroleum and Chemical Corp; Sinopec Dalian Research Institute of Petroleum and Petrochemicals
Current assignee: Sinopec Dalian Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2017-12-15
Filing date: 2017-12-15
Publication date: 2021-08-31
Anticipated expiration: 2037-12-15
Also published as: CN109926075A

Abstract

The invention provides a high-activity hydrotreating catalyst and a preparation method thereof, wherein the hydrotreating catalyst comprises a hydrotreating metal component, an auxiliary agent and a carrier, the hydrotreating metal component is one or more of VIB group metals and/or VIII group metals, Fe and P are auxiliary agents, and the carrier is an alumina and silicon dioxide composite carrier. The invention also provides a preparation method of the hydrotreating catalyst. The catalyst prepared by the method has reasonable distribution of metal components and high utilization rate, and reduces the acidity in the pore canal of the catalyst while ensuring the acidity of the outer surface of the catalyst, so that the catalyst has high catalytic activity and liquid yield.

Description

High-activity hydrotreating catalyst and preparation method thereof

Technical Field

The invention belongs to the field of petroleum processing, relates to a catalytic material and a preparation method thereof, and particularly relates to a hydrogenation catalyst and a preparation method thereof.

Background

With the annual reduction of sulfur content in the specifications of automotive fuel, hydrodesulfurization has become a main way for processing inferior raw materials to produce clean fuel. The activity of the hydrodesulfurization catalyst determines the economic efficiency of the overall hydrodesulfurization process. The high activity hydrodesulfurization catalyst can produce a low sulfur product under mild conditions, thereby extending the run length and saving operating costs.

Hydrodesulfurization catalysts usually use group VIB and group VIII metals as active components, and various auxiliaries can be added to improve the activity of the catalyst. At present, the catalyst preparation method commonly adopted in various countries in the world adopts a solution impregnation method, namely, active metal components are loaded on a carrier, and then the corresponding catalyst is obtained through the steps of drying, roasting and the like. The catalyst active component prepared by the preparation method is distributed on the inner and outer surfaces of the catalyst carrier, including the inner surface of the inner deep gap.

CN1872962A discloses a hydrotreating catalyst containing a molecular sieve, which takes alumina and a Y-type molecular sieve as carriers and loads active metal components of nickel, molybdenum and tungsten, namely, pseudo-boehmite and the molecular sieve are mechanically mixed and the active metal components are loaded step by step, so that the active components can be uniformly dispersed on the carriers, and the catalyst has higher hydrodesulfurization activity.

CN1339563A discloses a distillate oil hydrodesulfurization catalyst, which takes alumina or silicon-containing alumina as a carrier, molybdenum and nickel as active components, and adopts alkaline impregnation liquid to jointly impregnate the carrier in a segmented manner, so that the metal distribution on the catalyst is more uniform, and the distillate oil hydrodesulfurization activity of the catalyst is obviously improved.

CN1289828A discloses a distillate oil hydrorefining catalyst, which takes alumina or silicon-containing alumina as a carrier, W, Mo and Ni as active components, and a phosphorus additive is added. By adopting the sectional co-leaching technology, the metal distribution on the catalyst is more uniform, and the activity of the catalyst, particularly the hydrodenitrogenation activity, is greatly improved.

CN201110446040.5 discloses a preparation method of distillate oil hydrotreating catalyst, Ni, Co, W/Mo are active components, alumina or silicon-containing alumina is carrier, and P element is auxiliary agent. The active components are impregnated step by step, and the catalyst has high hydrodesulfurization activity.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a hydrotreating catalyst and a preparation method thereof, and the prepared catalyst has the advantages of high activity and high liquid yield when in use.

The first aspect of the invention provides a hydrotreating catalyst, which comprises a hydrotreating metal component, an auxiliary agent and a carrier, wherein the hydrotreating metal component is one or more of VIB group metals and/or VIII group metals, the auxiliary agent is Fe and P, the carrier is an alumina and silica composite carrier, wherein the alumina is wrapped by the silica, and the weight of the silica accounts for 3-10% of the weight of the alumina; based on the weight of the catalyst, the content of the hydrogenation metal component is 12.0-25%, the content of the auxiliary agent is 1.6-7.6%, and the content of the carrier is 67.4-86.4%.

In the hydroprocessing catalyst of the invention, the group VIB metal is typically Mo and/or W and the group VIII metal is typically Ni and/or Co.

In the hydrotreating catalyst of the invention, the auxiliary agents are Fe and P, and the weight of the catalyst is taken as a reference, Fe₂O₃Is 0.5% -3%, P₂O₅The content of (A) is 1.1-4.6%.

In the hydrotreating catalyst, the specific surface area of the hydrotreating catalyst is 200-260 m²(iv)/g, pore volume of 0.40 to 0.6mL/g, and average pore diameter of 7.0 to 12.0 nm.

In the hydrotreating catalyst of the invention, the hydrogenation metal components are uniformly distributed on the catalyst; the content of the auxiliary iron distributed in the range from 3/4 radiuses to the edge of the catalyst is 95.0-98.0 wt% of the total content of the auxiliary iron.

In the hydrotreating catalyst of the invention, the hydrogenation metal component is preferably Mo or Co, and MoO is used as the reference of the weight of the catalyst₃10-20% of Co₂O₃The content of (A) is 2-5%.

The second aspect of the present invention provides a preparation method of the above hydrotreating catalyst, which comprises the following steps:

(1) preparing an aqueous solution containing a hydrogenation metal component and an auxiliary agent P from a compound containing the hydrogenation metal component, a phosphorus-containing compound and water;

(2) modifying the alumina carrier by adopting the auxiliary agent A to obtain a catalyst precursor A;

(3) adding the catalyst precursor A obtained in the step (2) into an auxiliary agent B, uniformly mixing, carrying out solid-liquid separation, and standing the obtained solid phase at-50-0 ℃, preferably-30-0 ℃;

(4) adding an iron-containing compound aqueous solution into the material obtained in the step (3), carrying out solid-liquid separation after impregnation is finished, and drying a solid phase obtained by separation to obtain a catalyst precursor B;

(5) and (2) mixing the aqueous solution obtained in the step (1) with a catalyst precursor B, uniformly mixing, drying and roasting to obtain the catalyst.

In the preparation method, the compound containing the hydrogenation metal component in the step (1) is a compound containing a VIB group metal and/or a VIII group metal, the compound containing the VIB group metal can be one or more of a molybdenum-containing compound and a tungsten-containing compound, and the compound containing the VIII group metal is one or more of a cobalt-containing compound and a nickel-containing compound. The compound containing the hydrogenation metal component is preferably a molybdenum-containing compound and a cobalt-containing compound, and the molybdenum-containing compound can be molybdenum oxide and/or ammonium heptamolybdate; the cobalt-containing compound is basic cobalt carbonate and/or cobalt nitrate, and the phosphorus-containing compound can be one or more of phosphoric acid, ammonium dihydrogen phosphate and ammonium monohydrogen phosphate.

In the preparation method, the concentration of the hydrogenation metal component in the aqueous solution containing the hydrogenation metal component and the assistant P in the step (1) is 0.05-0.3 g/mL (calculated by the hydrogenation metal oxide), and the concentration of the assistant P is 0.005-0.05 g/mL. The formulation can be carried out by methods known in the art.

In the preparation method of the invention, the alumina carrier in the step (2) usually adopts spherical alumina, and the alumina carrier can be obtained by molding, drying and roasting pseudo-boehmite. The pseudo-boehmite can be prepared by a conventional method, such as an aluminum chloride method, an aluminum sulfate method, a carbonization method and the like.

In the preparation method, the properties of the alumina carrier in the step (2) are as follows: the pore volume is 0.6-0.9 mL/g, the specific surface area is 160-320 m²The grain diameter is 0.1 mm-1.2 mm.

In the preparation method of the invention, the modification treatment process in the step (2) is as follows:

(2.1) mixing the auxiliary agent A with an organic solvent, and uniformly mixing to obtain a solution I;

and (2.2) mixing the alumina carrier with the solution I, reacting after uniformly mixing, and drying to obtain a catalyst precursor B.

In the step (2.1), the assistant A is one or more of octadecyltrimethoxysilane, hexadecyltrimethoxysilane, dodecyltrimethoxysilane, octadecyltrichlorosilane, hexadecyltrichlorosilane and dodecyltrichlorosilane.

In the step (2.1), the organic solvent is one or more of benzene, toluene and cyclohexane, wherein the mass ratio of the auxiliary A to the organic solvent is 1: 1-1: 50.

In the step (2.2), the reaction temperature is 40-60 ℃, and the reaction time is 1.0-5.0 h; the drying temperature is 70-90 ℃, and the drying time is 3.0-12.0 h.

In the preparation method, the auxiliary agent B in the step (3) is diesel oil, the condensation point of the diesel oil is-40-20 ℃, preferably-40-0 ℃, and further preferably-30-0 ℃, the diesel oil can be one or more of straight-run diesel oil, hydrogenated diesel oil, coked diesel oil and catalytic diesel oil, preferably hydrogenated diesel oil is adopted, specifically commercially available commercial diesel oil such as one or more of 5# diesel oil, 0# diesel oil, -10# diesel oil, -20# diesel oil and-35 # diesel oil can be adopted, and the volume ratio of the auxiliary agent B to alumina is 1-4: 1, preferably 1-2: 1.

In the preparation method of the invention, the iron-containing compound in the step (4) can be one or more of ferric nitrate, ferric chloride and ferric sulfate.

In the preparation method, the solid phase obtained by separation in the step (4) is preferably subjected to high-temperature treatment in a nitrogen atmosphere, and a catalyst precursor B is obtained after treatment; the high-temperature treatment temperature is 300-400 ℃, and the time is 2.0-5.0 h.

In the preparation method, the drying temperature in the step (5) is 60-120 ℃, and the drying time is 3.0-12.0 h; the drying is preferably carried out in a two-stage drying mode, wherein the first-stage drying temperature is 60-90 ℃, and the second-stage drying temperature is 90-120 ℃; the roasting temperature is 400-700 ℃, and the roasting time is 2.0-6.0 h.

Compared with the prior art, the hydrotreating catalyst and the preparation method thereof have the following advantages:

1. the hydrotreating catalyst has the advantages of reasonable metal component distribution and high utilization rate, and can reduce the acidity in the catalyst pore passage while ensuring the acidity of the outer surface of the catalyst, so that the catalyst has high catalytic activity and high liquid yield.

2. In the preparation method of the hydrotreating catalyst, the additive A is introduced, so that the interaction between the additive B and the carrier can be promoted, the purpose of modifying the alumina carrier is realized, the additive iron can be supported on the surface of the carrier as much as possible under the combined action of the additive A and the additive B, and the acidity of the outer surface of the catalyst is ensured.

3. In the preparation method of the hydrotreating catalyst, the auxiliary agent A modifies the carrier, so that the outer surface of the alumina carrier is coated with the silicon dioxide, on one hand, the acid content in the pore channel of the catalyst is reduced, on the other hand, the coated silicon dioxide can also prevent strong interaction between the metal component and the carrier alumina, the active component is prevented from forming a spinel phase, the vulcanization of the loaded active component is facilitated, and the activity of the catalyst is further improved.

4. In the preparation method of the hydrotreating catalyst, the assistant iron and the carrier alumina interact with each other to improve the acidity of the carrier, and in the method, the content of the assistant iron distributed from 3/4 radiuses to the edge of the catalyst is 95.0wt% -98.0 wt% of the total content of the assistant iron, so that the acidity of the surface of the catalyst is ensured while the acidity in the pore channel of the catalyst is reduced, and the catalyst has high catalytic activity and liquid yield.

5. In the preparation method of the hydrotreating catalyst, the high-temperature treatment in the nitrogen atmosphere enables a large amount of carbon deposition to be generated on the surface of the carrier, so that the strong interaction between the metal component and the carrier can be effectively prevented, the active component is prevented from being generated to form a spinel phase, the vulcanization of the loaded active component is facilitated, and the activity of the catalyst is further improved.

Detailed Description

The invention is further illustrated by the following examples, in which wt% is the mass fraction.

The specific surface area and the pore volume are measured by adopting a low-temperature liquid nitrogen physical adsorption method, and are particularly measured by adopting a low-temperature nitrogen adsorption instrument of American Mike company ASAP2420 model; the specific process comprises the following steps: and (3) carrying out vacuum treatment on a small amount of sample at 300 ℃ for 3-4 h, and finally placing the product under the condition of low temperature (-200 ℃) of liquid nitrogen for nitrogen absorption-desorption test. Wherein the surface area is obtained according to a BET equation, and the pore size distribution is obtained according to a BJH model. SEM (scanning Electron microscope) specifically employed is a SEM (scanning electron microscope) of JSM-7500F type manufactured by JEOL corporation of Japan, equipped with EDAX-EDS, acceleration voltage: 20Kv, working distance: 8mm, resolution: 1 nm.

Example 1

(1) Preparation of Mo-Co-P aqueous solution:

4.6g of phosphoric acid H₃PO₄(the concentration is 85 wt%) is dissolved in 80mL of water, then 12.4g of molybdenum trioxide and 5.8g of basic cobalt carbonate are added, the temperature is raised to 100 ℃, the mixture is stirred and refluxed for 2.0h, and the volume is 100mL after filtration, so that the Mo-Co-P aqueous solution is obtained. Wherein MoO₃Is 0.12g/mL, Co₂O₃The concentration of (B) was 0.03g/mL, and the concentration of P was 0.012 g/mL.

(2) Preparation of the catalyst:

73.1g of an alumina carrier (pore volume of 0.70mL/g, specific surface area of 300 m)²Spherical, particle diameter 0.4 mm-0.6 mm) was added to 200mL of cyclohexane solution containing 36.7g of dodecyltrimethoxysilane, reacted at 50 ℃ for 3.0h, dried at 70 ℃ for 8h to obtain catalyst precursor A; then adding the mixture into 200mL5# diesel oil, soaking for 30min, filtering, and placing the obtained material in a low-temperature reaction bath at 0 ℃. Then adding 100mL of aqueous solution containing 5.1g of ferric nitrate, soaking for 2h, filtering, and carrying out high-temperature treatment on the obtained solid at 350 ℃ for 4.0h under a nitrogen atmosphere to obtain a catalyst precursor B; diluting 100mL of an aqueous solution of Co-P to 150mL, adding the diluted solution to the catalyst precursor B, and mixingDrying at 70 deg.C for 4h, heating to 110 deg.C, drying for 4h, and calcining at 450 deg.C for 3.0h to obtain catalyst, wherein MoO₃Content of 12wt%, Co₂O₃3.0wt%, P1.2 wt%, Fe₂O₃The content is 1.0wt%, and the weight of the silicon dioxide accounts for 10% of the weight of the alumina. The physicochemical properties of the catalyst are shown in Table 1.

(3) Catalyst characterization:

performing element analysis on the catalyst through SEM, and uniformly distributing molybdenum oxide and cobalt oxide on the catalyst; the iron oxide content was 98.0wt% of the total content in the range from 3/4 radius to the edge of the catalyst.

(4) Evaluation of catalyst:

the catalyst evaluation was carried out on a microreaction device, and the catalyst was presulfided before the activity evaluation. The evaluation conditions of the catalyst are that the hydrogen pressure is 6.0 MPa, and the liquid hourly volume space velocity is 2.0h^-1The hydrogen-oil ratio is 500:1, and the reaction temperature is 340 ℃. Activity evaluation the properties of the raw oil are shown in Table 2. The results of the activity evaluation are shown in Table 3.

Example 2

(1) Preparation of Mo-Co-P aqueous solution:

5.7g of phosphoric acid H₃PO₄(the concentration is 85 wt%) is dissolved in 80mL of water, then 15.6g of molybdenum trioxide and 7.2g of basic cobalt carbonate are added, the temperature is raised to 100 ℃, the mixture is stirred and refluxed for 2.0h, and the volume is 100mL after filtration, so that the Mo-Co-P aqueous solution is obtained. Wherein MoO₃Is 0.15g/mL, Co₂O₃The concentration of (2) was 0.038g/mL, and the concentration of P was 0.015 g/mL.

(2) Preparation of the catalyst:

70.1g of an alumina carrier (pore volume of 0.70mL/g, specific surface area of 300 m)²Spherical, particle diameter 0.4 mm-0.6 mm) was added to 200mL of cyclohexane solution containing 33.1g of hexadecyltrimethoxysilane, reacted at 50 ℃ for 3.0h, dried at 70 ℃ for 8h to obtain catalyst precursor A; then adding the mixture into 200mL0# diesel oil, soaking for 30min, filtering, and placing the obtained material into a low-temperature reaction bath at the temperature of minus 10 ℃. Then, 100mL of an aqueous solution containing 7.6g of ferric nitrate was added, the mixture was immersed for 2 hours and then filtered, and the obtained solid was collectedTreating the precursor at 350 ℃ for 4.0h in a nitrogen atmosphere to obtain a catalyst precursor B; diluting 100mL of aqueous solution of Co-P to 150mL, adding the diluted aqueous solution into a catalyst precursor B, uniformly mixing, drying at 70 ℃ for 4h, heating to 110 ℃ for drying for 4h, and roasting at 450 ℃ for 3.0h to obtain the catalyst, wherein MoO is₃15wt% of Co₂O₃3.8wt%, P1.5 wt%, Fe₂O₃The content is 1.5wt%, and the weight of the silicon dioxide accounts for 8% of the weight of the alumina. The physicochemical properties of the catalyst are shown in Table 1.

(3) Catalyst characterization:

(4) Evaluation of catalyst:

the catalyst was evaluated in the same manner as in example 1, and the results of the activity evaluation are shown in Table 3.

Example 3

(1) Preparation of Mo-Co-P aqueous solution:

(2) Preparation of the catalyst:

71.9g of an alumina carrier (pore volume of 0.70mL/g, specific surface area of 300 m)²Spherical, particle diameter 0.4 mm-0.6 mm) was added to 200mL of cyclohexane solution containing 20.6g of hexadecyltrimethoxysilane, reacted at 50 ℃ for 3.0h, dried at 70 ℃ for 8h to obtain catalyst precursor A; then adding the mixture into 200mL0# diesel oil, soaking for 30min, filtering, and placing the obtained material into a low-temperature reaction bath at the temperature of minus 10 ℃. Then adding 100mL of aqueous solution containing 10.1g of ferric nitrate, soaking for 2h, filtering, and treating the obtained solid at 350 ℃ for 4.0h under nitrogen atmosphere to obtain the catalystA precursor B; diluting 100mL of aqueous solution of Co-P to 150mL, adding the diluted aqueous solution into a catalyst precursor B, uniformly mixing, drying at 70 ℃ for 4h, heating to 110 ℃ for drying for 4h, and roasting at 450 ℃ for 3.0h to obtain the catalyst, wherein MoO is₃15wt% of Co₂O₃3.8wt%, P1.5 wt%, Fe₂O₃The content is 2.0wt%, and the weight of the silicon dioxide accounts for 5% of the weight of the alumina. The physicochemical properties of the catalyst are shown in Table 1.

(3) Catalyst characterization:

performing element analysis on the catalyst through SEM, and uniformly distributing molybdenum oxide and cobalt oxide on the catalyst; the iron oxide content was 97.5wt% of the total content, distributed over a radius of 3/4 to the edge of the catalyst.

(4) Evaluation of catalyst:

Example 4

(1) Preparation of Mo-Co-P aqueous solution:

6.9g of phosphoric acid H₃PO₄(the concentration is 85 wt%) is dissolved in 80mL of water, 18.6g of molybdenum trioxide and 8.7g of basic cobalt carbonate are added, the temperature is raised to 100 ℃, the mixture is stirred and refluxed for 2.0h, and the volume is 100mL after filtration, so that the Mo-Co-P aqueous solution is obtained. Wherein MoO₃Is 0.18g/mL, Co₂O₃The concentration of (B) was 0.045g/mL, and the concentration of P was 0.018 g/mL.

(2) Preparation of the catalyst:

68.7g of an alumina carrier (pore volume of 0.70mL/g, specific surface area of 300 m)²Spherical, particle diameter 0.4 mm-0.6 mm) was added to 200mL of cyclohexane solution containing 12.3g of octadecyltrimethoxysilane, reacted at 50 ℃ for 3.0h, dried at 70 ℃ for 8h to obtain catalyst precursor A; then adding the mixture into 200mL-10# diesel oil, soaking for 30min, filtering, and placing the obtained material into a low-temperature reaction bath at the temperature of-20 ℃. Then adding 100mL of aqueous solution containing 13.2g of ferric nitrate, soaking for 2h, filtering, and carrying out high-temperature treatment on the obtained solid at 350 ℃ for 4.0h under a nitrogen atmosphere to obtain a catalyst precursor B; diluting 100mL of an aqueous solution of Co-P to 150mL, and adding the diluted solution to a reaction vesselUniformly mixing the catalyst precursor B, drying at 70 ℃ for 4h, heating to 110 ℃ for drying for 4h, and roasting at 450 ℃ for 3.0h to obtain the catalyst, wherein MoO is₃18wt% of Co₂O₃4.5wt%, P1.8 wt%, Fe₂O₃The content is 2.5wt%, and the weight of the silicon dioxide accounts for 3% of the weight of the alumina. The physicochemical properties of the catalyst are shown in Table 1.

(3) Catalyst characterization:

performing element analysis on the catalyst through SEM, and uniformly distributing molybdenum oxide and cobalt oxide on the catalyst; the iron oxide content was 97.0wt% of the total content, distributed over a radius of 3/4 to the edge of the catalyst.

(4) Evaluation of catalyst:

Example 5

(1) Preparation of the catalyst:

in example 1, the catalyst was prepared by treating the mixture at 350 ℃ for 4.0h in a nitrogen atmosphere and drying the mixture at 110 ℃ for 8.0h under a relative vacuum of-0.1 MPa to obtain a catalyst in which MoO was present₃Content of 12wt%, Co₂O₃3.0wt%, P1.2 wt%, Fe₂O₃The content is 1.0wt%, and the weight of the silicon dioxide accounts for 10% of the weight of the alumina. The physicochemical properties of the catalyst are shown in Table 1.

(2) Catalyst characterization:

(3) Evaluation of catalyst:

Comparative example 1

(1) Preparation of the catalyst:

in example 1, 100mL of an aqueous Mo-Co-P solution and 50mL of an aqueous solution containing 5.1g of ferric nitrate were mixed, and then 81.2g of an alumina support (pore volume: Mo-Co-P) was added0.70mL/g, and a specific surface area of 300m²Spherical and with particle diameter of 0.4 mm-0.6 mm), uniformly mixing, drying at 70 ℃ for 4h, then heating to 110 ℃ for drying for 4h, roasting the obtained solid at 450 ℃ for 3.0h to obtain the catalyst, wherein MoO is the catalyst₃Content of 12wt%, Co₂O₃3.0wt%, P1.2 wt%, Fe₂O₃The content was 1.0 wt%. The physicochemical properties of the catalyst are shown in Table 1.

(2) Catalyst characterization:

elemental analysis of the catalyst by SEM showed that molybdenum oxide, cobalt oxide and iron oxide were uniformly distributed over the catalyst.

(3) Evaluation of catalyst:

Comparative example 2

The process is substantially the same as in example 1, except that the alumina carrier is not modified with the aid of dodecyltrimethoxysilane.

(1) Preparation of the catalyst:

81.2g of an alumina carrier (pore volume of 0.70mL/g, specific surface area of 300 m)²Spherical, particle diameter 0.4 mm-0.6 mm) into 200mL5# diesel oil, soaking for 30min, filtering, and placing the obtained material in a low-temperature reaction bath at 0 ℃. Adding 100mL of aqueous solution containing 5.1g of ferric nitrate into the materials, soaking for 2h, filtering, and treating the obtained solid at 350 ℃ for 4.0h under a nitrogen atmosphere to obtain a catalyst precursor; diluting 100mL of aqueous solution of Co-P to 150mL, adding the diluted aqueous solution into a catalyst precursor, uniformly mixing, drying at 70 ℃ for 4h, heating to 110 ℃ for drying for 4h, and roasting at 450 ℃ for 3.0h to obtain the catalyst, wherein MoO is₃Content of 12wt%, Co₂O₃3.0wt%, P1.2 wt%, Fe₂O₃The content was 1.0 wt%. The physicochemical properties of the catalyst are shown in Table 1.

(2) Catalyst characterization:

(3) Evaluation of catalyst:

The assistant A modifies the catalyst, so that the outer surface of the alumina carrier is coated with silicon dioxide, on one hand, the acidity of the carrier can be weakened, on the other hand, the coated silicon dioxide can also prevent strong interaction between the metal component and the carrier alumina, the active component is prevented from forming a spinel phase, the vulcanization of the loaded active component is facilitated, and the activity of the catalyst is further improved. Therefore, compared with example 1, the catalyst of comparative example 2 is not modified by aid A, the outer surface of the alumina carrier is not coated with silica, and the acidity of the catalyst is not weakened. Thus, both the conversion and the selectivity of the catalyst are affected.

Comparative example 3

Substantially the same as in example 1 except that the catalyst precursor A was not treated with the assistant B.

(1) Preparation of the catalyst:

adding the catalyst precursor A into 100mL of aqueous solution containing 5.1g of ferric nitrate, soaking for 2h, filtering, and treating the obtained solid at 350 ℃ for 4.0h under a nitrogen atmosphere to obtain a catalyst precursor B; diluting 100mL of aqueous solution of Co-P to 150mL, adding the diluted aqueous solution into a catalyst precursor B, uniformly mixing, drying at 70 ℃ for 4h, heating to 110 ℃ for drying for 4h, and roasting at 450 ℃ for 3.0h to obtain the catalyst, wherein MoO is₃Content of 12wt%, Co₂O₃3.0wt%, P1.2 wt%, Fe₂O₃The content is 1.0wt%, and the weight of the silicon dioxide accounts for 10% of the weight of the alumina. The physicochemical properties of the catalyst are shown in Table 1.

(2) Catalyst characterization:

(3) Evaluation of catalyst:

TABLE 1 Properties of the catalysts

TABLE 2 Properties of the feed oils

TABLE 3 evaluation results of catalyst Activity

Claims

1. A hydrotreating catalyst comprises a hydrotreating metal component, an auxiliary agent and a carrier, wherein the hydrotreating metal component is one or more of VIB group metals and/or VIII group metals, the auxiliary agent is Fe and P, and the carrier is an alumina and silica composite carrier; based on the weight of the catalyst, the content of the hydrogenation metal component is 12.0-25%, the content of the auxiliary agent is 1.6-7.6%, and the content of the carrier is 67.4-86.4%;

the preparation method of the hydrotreating catalyst comprises the following steps:

(2) modifying the alumina carrier by adopting an auxiliary agent A to obtain a catalyst precursor A, wherein the auxiliary agent A is one or more of octadecyl trimethoxy silane, hexadecyl trimethoxy silane, dodecyl trimethoxy silane, octadecyl trichlorosilane, hexadecyl trichlorosilane and dodecyl trichlorosilane;

(3) mixing the catalyst precursor A obtained in the step (2) with an auxiliary agent B, uniformly mixing, carrying out solid-liquid separation, and standing the separated solid phase at-50-0 ℃, wherein the auxiliary agent B is diesel oil;

(4) mixing an iron-containing compound aqueous solution with the material obtained in the step (3), carrying out solid-liquid separation after impregnation is finished, and drying a solid phase obtained by separation to obtain a catalyst precursor B;

2. The hydrotreating catalyst according to claim 1, characterized in that: the VIB group metal is Mo and/or W, and the VIII group metal is Ni and/or Co.

3. The hydrotreating catalyst according to claim 1, characterized in that: the weight of the silicon dioxide accounts for 3-10% of the weight of the alumina.

4. The hydrotreating catalyst according to claim 1, characterized in that: the auxiliary agent is Fe and P, and the weight of the catalyst is taken as a reference, Fe₂O₃Is 0.5% -3%, P₂O₅The content of (A) is 1.1-4.6%.

5. The hydrotreating catalyst according to claim 1, characterized in that: the specific surface area of the hydrogenation catalyst is 200-260 m²(iv)/g, pore volume of 0.40 to 0.6mL/g, and average pore diameter of 7.0 to 12.0 nm.

6. The hydrotreating catalyst according to claim 1, characterized in that: the hydrogenation metal components are uniformly distributed on the catalyst; the content of the auxiliary iron distributed in the range from the radius of the catalyst 3/4 to the outer edge of the catalyst is 95.0wt% -98.0 wt% of the total content of the auxiliary iron.

7. The hydrotreating catalyst according to claim 1, characterized in that: the hydrogenation metal components are Mo and Co, and MoO is based on the weight of the catalyst₃10-20% of Co₂O₃The content of (A) is 2-5%.

8. The process for producing a hydrotreating catalyst as recited in any of claims 1 to 7, characterized in that: the preparation method comprises the following steps:

9. The method of claim 8, wherein: and (3) mixing the catalyst precursor A obtained in the step (2) with an auxiliary agent B, uniformly mixing, performing solid-liquid separation, and standing the separated solid phase at-30-0 ℃.

10. The method of claim 8, wherein: the compound containing the hydrogenation metal component in the step (1) is a compound containing VIB group metal and/or a compound containing VIII group metal.

11. The method of claim 10, wherein: the group VIB metal-containing compound is one or more of molybdenum-containing compound and tungsten-containing compound, and the group VIII metal-containing compound is one or more of cobalt-containing compound and nickel-containing compound.

12. The method of claim 8, wherein: the compound containing the hydrogenation metal component is a molybdenum-containing compound and a cobalt-containing compound.

13. The production method according to claim 11 or 12, characterized in that: the molybdenum-containing compound is molybdenum oxide and/or ammonium heptamolybdate; the cobalt-containing compound is basic cobalt carbonate and/or cobalt nitrate.

14. The method of claim 8, wherein: the phosphorus-containing compound is one or more of phosphoric acid, ammonium dihydrogen phosphate and ammonium monohydrogen phosphate.

15. The method of claim 8, wherein: the concentration of the hydrogenation metal component in the aqueous solution containing the hydrogenation metal component and the auxiliary agent P in the step (1) is 0.05-0.3 g/mL, and the concentration of the auxiliary agent P is 0.005-0.05 g/mL.

16. The method of claim 8, wherein: the modification treatment process in the step (2) is as follows:

and (2.2) mixing the alumina carrier with the solution I, reacting after uniformly mixing, and drying to obtain the catalyst precursor A.

17. The method of claim 16, wherein: the organic solvent in the step (2.1) is one or more of benzene, toluene and cyclohexane.

18. The method of claim 16, wherein: the mass ratio of the auxiliary agent A to the organic solvent is 1: 1-1: 50.

19. The method of claim 16, wherein: in the step (2.2), the reaction temperature is 40-60 ℃, and the reaction time is 1.0-5.0 h; the drying temperature is 70-90 ℃, and the drying time is 3.0-12.0 h.

20. The method of claim 8, wherein: the condensation point of the diesel oil is-40-20 ℃.

21. The production method according to claim 8 or 20, characterized in that: the condensation point of the diesel oil is-40-0 ℃.

22. The production method according to claim 8 or 20, characterized in that: the condensation point of the diesel oil is-30-0 ℃.

23. The method of claim 8, wherein: the diesel oil is one or more of straight-run diesel oil, hydrogenated diesel oil, coked diesel oil and catalytic diesel oil.

24. The production method according to claim 8 or 23, characterized in that: the diesel oil is hydrogenated diesel oil.

25. The method of claim 8, wherein: the diesel oil is commercial diesel oil, and the commercial diesel oil is one or more of 5# diesel oil, 0# diesel oil, -10# diesel oil, -20# diesel oil and-35 # diesel oil.

26. The method of claim 8, wherein: the volume ratio of the auxiliary agent B to the alumina is 1-4: 1.

27. The method of claim 8, wherein: the volume ratio of the auxiliary agent B to the alumina is 1-2: 1.

28. The method of claim 8, wherein: in the step (4), the iron-containing compound is one or more of ferric nitrate, ferric chloride and ferric sulfate.

29. The method of claim 8, wherein: and (4) carrying out high-temperature treatment on the solid phase separated in the step (4) in a nitrogen atmosphere to obtain a catalyst precursor B after treatment.

30. The method of claim 29, wherein: the temperature of the high-temperature treatment is 300-400 ℃, and the time is 2.0-5.0 h.

31. The method of claim 8, wherein: in the step (5), the drying temperature is 60-120 ℃, and the drying time is 3.0-12.0 h; the roasting temperature is 400-700 ℃, and the roasting time is 2.0-6.0 h.

32. The method of claim 31, wherein: the drying is carried out in a two-stage drying mode, wherein the first-stage drying temperature is 60-90 ℃, and the second-stage drying temperature is 90-120 ℃.