阅读说明：本技术 加氢裂化催化剂及其制备方法和应用 (Hydrocracking catalyst, preparation method and application thereof ) 是由 毛以朝 龙湘云 杨清河 张润强 赵阳 赵广乐 于 2019-10-30 设计创作，主要内容包括：本发明涉及一种含择形分子筛及高硅材料的催化剂及制备,该催化剂包括以干基重量计的45～90重量％的载体,以金属氧化物计的1～40重量％的第一金属组分,和以金属氧化物计的1～15重量％的第二金属组分；载体中包括MFI分子筛和含磷高硅分子筛,该XRD谱图中,第一强峰的衍射角位置在5.9～6.9°,第二强峰的衍射角位置在10.0～11.0°,第三强峰的衍射角位置在15.6～16.7°。该催化剂具有较高的含氮物质存在下的加氢裂化活性。(The invention relates to a catalyst containing a shape-selective molecular sieve and a high-silicon material and a preparation method thereof, wherein the catalyst comprises 45-90 wt% of a carrier, 1-40 wt% of a first metal component and 1-15 wt% of a second metal component, wherein the carrier is calculated by the weight of a dry basis; the carrier comprises an MFI molecular sieve and a phosphorus-containing high-silicon molecular sieve, and in an XRD spectrogram, the diffraction angle position of a first strong peak is 5.9-6.9 degrees, the diffraction angle position of a second strong peak is 10.0-11.0 degrees, and the diffraction angle position of a third strong peak is 15.6-16.7 degrees. The catalyst has higher hydrocracking activity in the presence of nitrogen-containing substances.)

1. A hydrocracking catalyst, characterized in that the catalyst comprises 45 to 90 wt% of a carrier, 1 to 40 wt% of a first metal component calculated as a metal oxide, and 1 to 15 wt% of a second metal component calculated as a metal oxide, based on the dry weight of the catalyst;

the carrier comprises a phosphorus-containing high-silicon molecular sieve, an MFI molecular sieve and a heat-resistant inorganic oxide, and the first metal component is selected from group VIB metals; the second metal component is selected from group VIII metals;

calculated by oxide and based on the dry weight of the molecular sieve, the phosphorus-containing high-silicon molecular sieve has the silicon content of 90-99.8 wt%, the aluminum content of 0.3-3.0 wt% and the phosphorus content of 0.01-1.6 wt%; in an XRD spectrogram of the phosphorus-containing high-silicon molecular sieve, the diffraction angle position of a first intensity peak is 5.9-6.9 degrees, the diffraction angle position of a second intensity peak is 10.0-11.0 degrees, and the diffraction angle position of a third intensity peak is 15.6-16.7 degrees.

2. The catalyst of claim 1, wherein the weight ratio of the phosphorus-containing high-silicon molecular sieve, the MFI molecular sieve and the refractory inorganic oxide is 1: (0.03-20): (0.03-20); and/or the presence of a gas in the gas,

the phosphorus-containing high-silicon molecular sieve has the pore volume of 0.20-0.50 ml/g and the specific surface area of 260-600 m²/g。

3. The catalyst according to claim 1, wherein the phosphorus-containing high-silicon molecular sieve has an XRD spectrum in which the diffraction angle position of the first intensity peak is 6.1-6.8 °, the diffraction angle position of the second intensity peak is 10.2-10.7 °, and the diffraction angle position of the third intensity peak is 15.8-16.5 °.

4. The catalyst of any one of claims 1 to 3, wherein I in the XRD spectrum of the phosphorus-containing high-silicon molecular sieve₁/I_{23.5～24.5°}Is 3.0 to 11.0, I₂/I_{23.5～24.5°}Is 2.9 to 7.0, I₃/I_{23.5～24.5°}1.0 to 4.0, wherein I₁Is the peak height of the first strong peak, I₂Is the peak height of the second strong peak, I₃Is the peak height of the third strong peak, I_{23.5～24.5°}The peak height of the diffraction angle peak with the diffraction angle position of 23.5-24.5 degrees.

5. The catalyst of any one of claims 1 to 3, wherein the phosphorus-containing high-silicon molecular sieve has an XRD spectrum with a diffraction angle position of a fourth intensity peak of 20.4 to 21.6 degrees and a diffraction angle position of a fifth intensity peak of 11.8 to 12.8 degrees.

6. The catalyst according to claim 5, wherein the phosphorus-containing high-silicon molecular sieve has an XRD spectrum with a diffraction angle position of a fourth intensity peak in the range of 20.8-21.4 ° and a diffraction angle position of a fifth intensity peak in the range of 12.1-12.6 °; and/or the presence of a gas in the gas,

I₄/I_{23.5～24.5°}1.0 to 4.0, I₅/I_{23.5～24.5°}1.0 to 2.0, wherein I₄Is the peak height of the fourth strong peak, I₅Is the peak height of the fifth strong peak, I_{23.5～24.5°}The peak height of the diffraction angle peak with the diffraction angle position of 23.5-24.5 degrees.

7. The catalyst of any one of claims 1 to 3, wherein the MFI molecular sieve is one or more selected from ZRP, ZSP and ZSM-5 molecular sieves, the molecular sieve has a silica-alumina ratio of 20-120 and a specific surface area of 200-650 m²The pore volume is 0.20-0.75 ml/g.

8. The catalyst of any one of claims 1 to 3, wherein the preparation method of the phosphorus-containing high silicon molecular sieve comprises the following steps:

a. carrying out hydrothermal treatment on a phosphorus-containing molecular sieve raw material in the presence of water vapor to obtain a molecular sieve material after the hydrothermal treatment; calculated by oxide and based on the dry weight of the phosphorus-containing molecular sieve raw material, the phosphorus content of the phosphorus-containing molecular sieve raw material is 0.1-15 wt%, and the sodium content is 0.5-4.5 wt%;

b. b, adding water into the molecular sieve material subjected to the hydrothermal treatment obtained in the step a, pulping to obtain first slurry, heating the first slurry to 40-95 ℃, keeping the temperature, adding a first acid solution into the first slurry, wherein the adding amount of the first acid solution enables the pH value of the first slurry subjected to acid addition to be 2.5-4, carrying out constant temperature reaction for 0.5-20 h, and collecting a first solid product;

c. b, adding water into the first solid product obtained in the step b, pulping to obtain second slurry, heating the second slurry to 40-95 ℃, keeping the temperature, continuously adding a second acid solution into the second slurry, wherein the adding amount of the second acid solution enables the pH value of the second slurry after acid addition to be 1.0-2.0, then reacting at constant temperature for 0.5-20 h, and collecting a second solid product.

9. The catalyst of claim 8, wherein in the step a, the phosphorus-containing molecular sieve raw material is a phosphorus-containing Y-type molecular sieve, the unit cell constant of the phosphorus-containing Y-type molecular sieve is 2.425-2.47 nm, and the specific surface area is 250-750 m²The pore volume is 0.2 to 0.95 ml/g.

10. The catalyst of claim 8, wherein in the step a, the hydrothermal treatment conditions of the phosphorus-containing molecular sieve are as follows: carrying out hydro-thermal treatment on a phosphorus-containing molecular sieve raw material for 0.5-10 h at the temperature of 350-700 ℃ and the pressure of 0.1-2 MPa in the presence of water vapor to obtain a hydro-thermally treated molecular sieve material.

11. The catalyst of claim 8, wherein in step b, the ratio of the weight of water in the first slurry to the dry weight of the phosphorus-containing molecular sieve feedstock is (14-5): 1; and/or the presence of a gas in the gas,

in the step c, the ratio of the weight of water in the second slurry to the dry weight of the phosphorus-containing molecular sieve raw material is (0.5-20): 1.

12. the catalyst of claim 8, wherein in step c, the second acid solution is added by: based on 1L of the second slurry, taking H as reference⁺The second acid solution is added to the second slurry at a rate of 0.05 to 10 moles/hour.

13. The catalyst according to claim 8, wherein in the step b, the acid concentration of the first acid solution is 0.01 to 15.0mol/L, and the acid in the first acid solution is at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, formic acid and acetic acid; and/or the presence of a gas in the gas,

in the step c, the acid concentration of the second acid solution is 0.01-15.0 mol/L, and the acid in the second acid solution is at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, formic acid and acetic acid.

14. The catalyst of claim 8, wherein the step of preparing the phosphorus-containing high silicon molecular sieve further comprises: collecting the second product, then washing with water and drying to obtain a high-silicon phosphorus-containing molecular sieve; and/or, the drying conditions are as follows: the temperature is 50-350 ℃, and preferably 70-200 ℃; the time is 1-24 h, preferably 2-6 h.

15. The catalyst of claim 1, the heat-resistant inorganic oxide is alumina, silica, titania, zirconia, magnesia, boria, or a combination of two or three thereof; and/or the presence of a gas in the gas,

the first metal component is a molybdenum component and/or a tungsten component; the second metal component is an iron component, a nickel component, or a cobalt component, or a combination of two or three thereof.

16. A process for preparing a hydrocracking catalyst as claimed in any one of claims 1 to 15, comprising: mixing a phosphorus-containing high-silicon molecular sieve, an MFI molecular sieve and a heat-resistant inorganic oxide, and then molding, drying and roasting to obtain the carrier; and (3) contacting the impregnation liquid containing the first metal precursor and the second metal precursor with the carrier for impregnation, and drying and roasting the impregnated material.

17. The method of claim 16, wherein the first metal precursor is an inorganic acid, an inorganic salt, or an organic compound of a first metal; the inorganic salt is nitrate, carbonate, basic carbonate, hypophosphite, phosphate, sulfate or chloride; the organic substituent in the first metal organic compound is at least one selected from hydroxyl, carboxyl, amino, ketone, ether and alkyl; and/or the presence of a gas in the gas,

the second metal precursor is inorganic acid of a second metal, inorganic salt of the second metal or a second metal organic compound; the inorganic salt is nitrate, carbonate, basic carbonate, hypophosphite, phosphate, sulfate or chloride; the organic substituent in the second metal organic compound is at least one selected from hydroxyl, carboxyl, amino, ketone, ether and alkyl.

18. Use of a hydrocracking catalyst according to any one of claims 1 to 15 in a hydrocracking reaction of a hydrocarbon feedstock.

Technical Field

The invention relates to a hydrocracking catalyst, a preparation method and application thereof.

Background

Commercial hydrocracking feeds include heavy, inferior fractions such as VGO, containing significant amounts of polycyclic aromatic hydrocarbons and naphthenes, as well as significant amounts of nitrogen-containing compounds. Conventional hydrocracking feed nitrogen mass percentages are generally between 0.1 and 0.2. However, secondary processing of oil refining such as coking, solvent deasphalting, etc. often produces large amounts of nitrogen-containing compounds, often with nitrogen contents exceeding 0.3%, and some even reaching 0.6%, which makes it difficult to remove the nitrogen contents to 10-100ppm levels that can be tolerated by conventional molecular sieve type hydrocracking catalysts after the use of conventional refining catalysts. Amorphous silica-alumina or silica-containing alumina having weak acidity is generally used as an acidic component as a main acidic component of the high nitrogen content hydrocracking catalyst.

The prior art invention generally uses a solution of silicon oxide and aluminum oxide in salt to synthesize weakly acidic silicon aluminum at low pH, and also uses a method of grafting aluminum oxide on a silicon oxide precursor or grafting aluminum oxide on a silicon oxide precursor, and forming silicon aluminum tetrahedron by further reaction, thereby generating acidity in the sample.

ZL97121663.0 discloses a hydrocracking catalyst particularly suitable for the production of middle distillates, comprising an amorphous silica-alumina component and a small pore alumina binder, the amorphous silica-alumina content being 30-60% by weight, at least one group VIB element and at least one group VIII element, the total content of hydrogenation metal oxides being 20-35% by weightThe balance being a small-pore alumina adhesive, characterized in that the specific surface of the catalyst is 150-300 m²The volume of the pores is 0.25-0.50 ml/g, the pore size of the pores is 60-90%, and the infrared acidity is 0.30-0.50 mmol/g.

Although the methods can generate certain acidity, the materials are short-range ordered and difficult to achieve long-range ordered due to the existence of a large amount of non-framework six-coordinate aluminum in the obtained samples in order to keep the structure of the matrix stable in the synthesis process.

Disclosure of Invention

The invention aims to provide a hydrocracking catalyst, a preparation method and application thereof, wherein the catalyst has higher hydrocracking reaction activity and nitrogen resistance stability.

In order to achieve the above object, a first aspect of the present invention: there is provided a hydrocracking catalyst which comprises a base,

the catalyst comprises 45-90 wt% of a carrier, 1-40 wt% of a first metal component, and 1-15 wt% of a second metal component, on a dry basis.

The carrier comprises a phosphorus-containing high-silicon molecular sieve, an MFI molecular sieve and a heat-resistant inorganic oxide, wherein the weight ratio of the phosphorus-containing high-silicon molecular sieve to the MFI molecular sieve to the heat-resistant inorganic oxide is 1: (0.03-20): (0.03-20); the first metal component is a metal component selected from a group VIB metal; the second metal component is a metal component selected from group VIII metals.

The phosphorus-containing high-silicon molecular sieve has the pore volume of 0.20-0.50 ml/g and the specific surface area of 260-600 m²The phosphorus-containing high-silicon molecular sieve comprises, by weight, 90-99.8% of silicon, 0.3-3.0% of aluminum and 0.01-1.6% of phosphorus, wherein the percentages are calculated by oxides and based on the dry weight of the molecular sieve; in an XRD spectrogram of the phosphorus-containing high-silicon molecular sieve, the diffraction angle position of a first intensity peak is 5.9-6.9 degrees, the diffraction angle position of a second intensity peak is 10.0-11.0 degrees, and the diffraction angle position of a third intensity peak is 15.6-16.7 degrees

According to the technical scheme, the phosphorus-containing molecular sieve is adopted to carry out special hydrothermal treatment and two-step acid pickling treatment on the raw material to prepare the phosphorus-containing high-silicon molecular sieve with novel structural characteristics, and the hydrocracking catalyst prepared by adopting the phosphorus-containing high-silicon molecular sieve has higher hydrocracking activity and nitrogen stability resistance.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1 is an XRD spectrum of the molecular sieves prepared in preparation examples 1 to 2 and preparation comparative examples 1 to 3.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The catalyst of the present invention comprises 45 to 90 wt% of a carrier, based on the weight of the carrier on a dry basis, 1 to 40 wt% of a first metal component, based on the metal oxide, and 1 to 15 wt% of a second metal component, based on the metal oxide.

The carrier comprises a phosphorus-containing high-silicon molecular sieve, an MFI molecular sieve and a heat-resistant inorganic oxide, wherein the weight ratio of the phosphorus-containing high-silicon molecular sieve to the MFI molecular sieve to the heat-resistant inorganic oxide is 1: (0.03-20): (0.03-20); the first metal component is a metal component selected from a group VIB metal; the second metal component is a metal component selected from group VIII metals.

In the catalyst, the phosphorus-containing high-silicon molecular sieve used as a carrier component has special structure and performance, so that the hydrocracking catalyst has higher hydrocracking activity and nitrogen resistance stability. The phosphorus-containing high-silicon molecular sieve has the pore volume of 0.20-0.50 ml/g and the specific surface area of 260-600 m²The silicon content of the phosphorus-containing high-silicon molecular sieve is 90-99.8 percent by weight based on the dry basis weight of the molecular sieve and calculated by oxide0.3 to 3.0 wt% of aluminum and 0.01 to 1.6 wt% of phosphorus; in addition, the phosphorus-containing high-silicon molecular sieve can also contain a small amount of sodium, and the sodium content of the molecular sieve can be 0.01-1.0 wt% in terms of oxides and on the basis of the dry weight of the molecular sieve.

According to the invention, the phosphorus-containing high-silicon molecular sieve has different structural characteristics from the conventional silicon-aluminum material. Specifically, in an XRD spectrogram of the phosphorus-containing high-silicon molecular sieve, the diffraction angle position of a first intensity peak is 5.9-6.9, preferably 6.1-6.8 degrees; the diffraction angle position of the second strong peak is 10.0-11.0, preferably 10.2-10.7 degrees; the diffraction angle position of the third intensity peak is 15.6 to 16.7, preferably 15.8 to 16.5 °. It is well known to those skilled in the art that in the material structure analysis by X-ray diffraction (XRD), the D value (interplanar distance) can be generally calculated from the wavelength and diffraction angle, and the phase is preliminarily identified based on the features of the strongest three diffraction peaks, i.e., the first, second and third intensity peaks in the present invention. The concept of the three strong peaks can also be found in the literature, "Yi Yuan Gen Ming Dynasty" research method of heterogeneous catalysts [ M ]. Beijing: chemical industry Press, 1988.P140-170 ". Wherein, the diffraction angle position refers to the 2 theta angle value of the highest value of diffraction peak in the XRD spectrogram.

Further, in the XRD spectrogram of the phosphorus-containing high-silicon molecular sieve, I₁/I_{23.5～24.5°}Can be 3.0 to 11.0, I₂/I_{23.5～24.5°}Can be 2.9 to 7.0, I₃/I_{23.5～24.5°}Can be 1.0 to 4.0, wherein I₁Is the peak height of the first strong peak, I₂Is the peak height of the second strong peak, I₃Is the peak height of the third strong peak, I_{23.5～24.5°}The peak height of the diffraction angle peak with the diffraction angle position of 23.5-24.5 degrees.

Further, in the XRD spectrogram of the phosphorus-containing high-silicon molecular sieve, the diffraction angle position of a fourth intensity peak can be 20.4-21.6 degrees, preferably 20.8-21.4 degrees, and the diffraction angle position of a fifth intensity peak can be 11.8-12.8 degrees, preferably 12.1-12.6 degrees. Further, I₄/I_{23.5～24.5°}Can be 1.0-4.0, I₅/I_{23.5～24.5°}Can be 1.0 to 2.0, wherein I₄Is the peak height of the fourth strong peak, I₅Is the peak height of the fifth strong peak, I_{23.5～24.5°}The peak height of the diffraction angle peak with the diffraction angle position of 23.5-24.5 degrees. The concept of the fourth strong peak and the fifth strong peak can be understood according to the description of the three strong peaks, and will not be described herein again.

The phosphorus-containing high-silicon molecular sieve is prepared by carrying out special hydrothermal treatment and two-step acid washing treatment on a phosphorus-containing molecular sieve raw material. Specifically, the phosphorus-containing high-silicon molecular sieve is prepared by a method comprising the following steps:

a. carrying out hydrothermal treatment on a phosphorus-containing molecular sieve raw material in the presence of water vapor to obtain a molecular sieve material after the hydrothermal treatment; calculated by oxide and based on the dry weight of the phosphorus-containing molecular sieve raw material, the phosphorus content of the phosphorus-containing molecular sieve raw material is 0.1-15 wt%, and the sodium content is 0.5-4.5 wt%;

b. b, adding water into the molecular sieve material subjected to the hydrothermal treatment obtained in the step a, pulping to obtain first slurry, heating the first slurry to 40-95 ℃, keeping the temperature, adding a first acid solution into the first slurry, wherein the adding amount of the first acid solution enables the pH value of the first slurry subjected to acid addition to be 2.5-4, carrying out constant temperature reaction for 0.5-20 h, and collecting a first solid product;

c. b, adding water into the first solid product obtained in the step b, pulping to obtain second slurry, heating the second slurry to 40-95 ℃, keeping the temperature, continuously adding a second acid solution into the second slurry, wherein the adding amount of the second acid solution enables the pH value of the acid-added second slurry to be 1.0-2.0, reacting at constant temperature for 0.5-20 h, and collecting a second solid product.

According to the invention, in the step a, the hydrothermal treatment conditions of the phosphorus molecular sieve raw material are as follows: carrying out hydro-thermal treatment on a phosphorus-containing molecular sieve raw material for 0.5-10 h at the temperature of 350-700 ℃ and the pressure of 0.1-2 MPa in the presence of water vapor to obtain a hydro-thermally treated molecular sieve material; the phosphorus-containing molecular sieve raw material refers to a phosphorus-containing molecular sieve. The invention adopts phosphorus-containing molecular sieve as raw material, molecular sieve boneThe extra-framework phosphor aluminum species can improve the framework stability of the molecular sieve, thereby further improving the performance of the molecular sieve. The structure of the phosphorus-containing molecular sieve raw material can be an octahedral zeolite molecular sieve structure, preferably a phosphorus-containing Y-type molecular sieve, the unit cell constant of the phosphorus-containing molecular sieve raw material can be 2.425-2.47 nm, and the specific surface area of the phosphorus-containing molecular sieve raw material can be 250-750 m²The pore volume may be 0.2 to 0.95 ml/g. Further, the specific selection of the Y-type molecular sieve may be widely varied as long as the phosphorus-containing molecular sieve raw material satisfies the above conditions, and for example, the Y-type molecular sieve may be selected from NaY, HNaY (hydrogen Y-type molecular sieve), REY (rare earth Y-type molecular sieve), USY (ultra stable Y-type molecular sieve), and the like. The cation position of the phosphorus-containing Y-type molecular sieve can be occupied by one or more of sodium ions, ammonium ions and hydrogen ions; alternatively, the sodium, ammonium, and hydrogen ions may be replaced by other ions, either before or after the molecular sieve is introduced with phosphorus, by conventional ion exchange. The phosphorus-containing molecular sieve raw material can be a commercial product, and can also be prepared by any prior art, for example, a method for preparing USY disclosed by a patent ZL00123139.1, a method for preparing PUSY disclosed by a patent ZL200410071122.6 and the like can be adopted, and the details of the invention are not repeated.

The meaning of said water addition beating in step b and step c according to the present invention is well known to the person skilled in the art. In the step b, the ratio of the weight of water in the first slurry obtained after pulping to the dry basis weight of the phosphorus-containing molecular sieve raw material can be (14-5): 1. in the step c, the ratio of the weight of water in the second slurry to the dry weight of the phosphorus-containing molecular sieve raw material may be (0.5-20): 1.

according to the invention, in the step b, the first slurry is preferably heated to 50-85 ℃, then the temperature is maintained, and the first acid solution is continuously added into the first slurry until the pH value of the first slurry after the acid addition reaches the required value. The amount of the first acid solution added can vary widely according to the nature of the phosphorus-containing molecular sieve feedstock and the hydrothermal treatment conditions of step a, and it will be understood by those skilled in the art that the amount of the first acid solution added is reasonable as long as the pH of the acidified first slurry meets the above suitable range. The rate of addition of the first acid solution is not particularly limited and may vary over a wide range.

According to the invention, in the step b, the operation of adding the first acid solution may be performed multiple times (for example, 1 to 5 times), and after each time of adding the acid, the reaction may be performed at a constant temperature for a period of time, and then the next time of adding the acid is continued until the pH value of the first slurry after adding the acid reaches a required range. The acid concentration of the first acid solution can be 0.1-15.0 mol/L, and the pH value can be 0.01-3. The acid in the first acid solution may be a conventional inorganic acid and/or organic or acid, and may be, for example, at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, formic acid, and acetic acid.

According to the invention, in step c, the second slurry is preferably heated to 50-85 ℃, then the temperature is maintained, and the second acid solution is continuously added into the second slurry until the pH value of the acid-added second slurry reaches the required value. The second acid solution may be added in a manner that: based on 1L of the second slurry, taking H as reference⁺And adding the second acid solution into the second slurry at a speed of 0.05-10 mol/h. Thus, the acid adding speed is slower in the step c, so that the dealumination process is more moderate, and the performance of the molecular sieve is favorably improved.

According to the invention, in the step c, the operation of adding the second acid solution may be performed multiple times (for example, 1 to 5 times), and after each acid addition, the reaction may be performed at constant temperature for a period of time, and then the next acid addition is continued until the pH value of the second slurry after the acid addition reaches the required range. The acid concentration of the second acid solution can be 0.1-15.0 mol/L, and the pH value can be 0.01-3. The acid in the second acid solution may be a conventional inorganic acid and/or organic or acid, and may be, for example, at least one selected from phosphoric acid, sulfuric acid, nitric acid, hydrochloric acid, acetic acid, citric acid, tartaric acid, formic acid, and acetic acid. The second acid solution may be the same as or different from the first acid solution in terms of kind and concentration, and is preferably the same acid solution.

According to the present invention, the preparation steps of the phosphorus-containing high silicon molecular sieve may further comprise: and collecting the second product, and then washing and drying to obtain the phosphorus-containing high-silicon molecular sieve. The washing and drying are conventional steps for preparing the molecular sieve, and the present invention is not particularly limited. For example, the drying may be performed by using an oven, a mesh belt, a converter, or the like, and the drying conditions may be: the temperature is 50-350 ℃, and preferably 70-200 ℃; the time is 1-24 h, preferably 2-6 h.

According to the invention, the MFI molecular sieve is selected from one or more of ZRP, ZSP and ZSM-5 molecular sieves, the silica-alumina ratio of the molecular sieve is 20-120, and the specific surface area is 200-650 m²The pore volume is 0.20-0.75 ml/g.

According to the invention, the heat-resistant inorganic oxide can improve the strength of the catalyst, and improve and adjust the physicochemical properties of the catalyst, such as improving the pore structure of the catalyst. The heat-resistant inorganic oxide may be an inorganic oxide commonly used for hydrogenation catalyst supports, such as alumina, silica, titania, zirconia, magnesia, boria, and the like. In a preferred embodiment of the invention, the heat resistant inorganic oxide is alumina, which may include gibbsite such as gibbsite (gibbsite), bayerite nordstrandite (bayerite) and diaspore such as boehmite (boehmite, diasporite, pseudoboehmite). In other embodiments, the refractory inorganic oxide is of another species or combination.

According to the present invention, preferably, the first metal is a molybdenum component and/or a tungsten component; the second metal component is an iron component, a nickel component, or a cobalt component, or a combination of two or three thereof.

Second aspect of the invention: there is provided a process for preparing a hydrocracking catalyst according to the first aspect of the present invention, which process comprises: mixing a high-silicon phosphorus-containing molecular sieve, an MFI molecular sieve and a heat-resistant inorganic oxide, and then molding and drying to obtain the carrier; and (3) contacting an impregnation liquid containing a first metal precursor and a second metal precursor with a carrier for impregnation, and drying and roasting the impregnated material.

The contact impregnation method of the impregnation liquid and the carrier can adopt any method known in the art, such as a method disclosed in patent CN200810241082.3, which comprises loading a group VIB metal component, a group VIII metal component and an organic additive on the catalyst carrier.

Methods for preparing the carrier are well known to those skilled in the art, and the present disclosure is not particularly limited. The molding method can adopt various conventional methods, such as tabletting molding, rolling ball molding or extrusion molding.

The shape of the carrier is not particularly required in the present invention, and may be spherical, strip-shaped, hollow strip-shaped, spherical, block-shaped, etc., and the strip-shaped carrier may be cloverleaf-shaped, clover-shaped, etc., or a variant thereof.

According to the invention, the first metal precursor is a soluble compound containing the first metal, and comprises at least one of inorganic acid of the first metal, inorganic salt of the first metal and organic compound of the first metal; the inorganic salt may be at least one selected from the group consisting of nitrate, carbonate, hydroxycarbonate, hypophosphite, phosphate, sulfate and chloride; the organic substituent in the first metal organic compound is at least one selected from hydroxyl, carboxyl, amino, ketone, ether and alkyl. For example, when the first metal is molybdenum, the first metal precursor may be at least one selected from the group consisting of molybdic acid, paramolybdic acid, molybdate, paramolybdate, and the like; when the first metal is tungsten, the first metal precursor may be at least one selected from the group consisting of tungstic acid, metatungstic acid, ethyl metatungstic acid, tungstate, metatungstate, and ethyl metatungstate. The second metal precursor is a soluble compound containing the second metal and comprises at least one of inorganic acid of the second metal, inorganic salt of the second metal and organic compound of the second metal; the inorganic salt may be at least one selected from the group consisting of nitrate, carbonate, hydroxycarbonate, hypophosphite, phosphate, sulfate and chloride; the organic substituent in the second metal organic compound is at least one selected from hydroxyl, carboxyl, amino, ketone, ether and alkyl.

According to the invention, the impregnation liquid may also contain organic additives; the concentration of the organic additive can be 2-300 g/L. The organic additive is an oxygen-containing organic compound and/or a nitrogen-containing organic compound. Specifically, the oxygen-containing organic compound may be at least one selected from the group consisting of ethylene glycol, glycerol, polyethylene glycol (molecular weight may be 200 to 1500), diethylene glycol, butanediol, acetic acid, maleic acid, oxalic acid, nitrilotriacetic acid, 1, 2-cyclohexanediaminetetraacetic acid, citric acid, tartaric acid, and malic acid; the nitrogen-containing organic compound may be at least one selected from the group consisting of ethylenediamine, diethylenetriamine, cyclohexanediaminetetraacetic acid, glycine, nitrilotriacetic acid, ethylenediaminetetraacetic acid and ammonium ethylenediaminetetraacetate.

In the method for producing a hydrocracking catalyst of the present invention, the contacting temperature is not particularly limited, and may be any of various temperatures that can be attained by the impregnation liquid. The time for the impregnation is also not particularly limited as long as the catalyst carrier can be supported with the desired amount of the metal active component precursor. In general, the higher the impregnation temperature, the higher the concentration of the impregnation solution, and the shorter the time required to achieve the same impregnation amount (i.e., the weight difference between the catalyst support after impregnation and the catalyst support before impregnation); and vice versa. When the desired amount and conditions of impregnation are determined, one skilled in the art can readily select an appropriate impregnation time based on the teachings of the present invention. The impregnation method of the present invention is not particularly limited, and the impregnation may be either saturated impregnation or supersaturated impregnation. The impregnation may be carried out under a sealed condition or in an open environment according to a conventional method in the art, and the loss of the aqueous solvent may or may not be replenished during the impregnation. Various gases, such as air, nitrogen, water vapor, etc., may be introduced during the impregnation process, or any new components may not be introduced.

The method for preparing the hydrocracking catalyst of the present invention further comprises the step of drying and calcining the impregnated material obtained, wherein the drying and calcining are conventional steps for preparing the catalyst, and the present invention is not particularly limited. For example, the drying conditions may be: the temperature is 80-350 ℃, preferably 100-300 ℃, and the time is 0.5-24 hours, preferably 1-12 hours. The roasting conditions can be as follows: the temperature is 350-600 ℃, and preferably 400-550 ℃; the time is 0.2 to 12 hours, preferably 1 to 10 hours.

The hydrocracking catalyst provided by the invention can be used as various acid catalytic catalysts for catalytic cracking, hydroisomerization, alkylation, hydrocracking and other reactions, and is particularly suitable for hydrocracking hydrocarbon raw materials to produce hydrocarbon fractions with lower boiling points and lower molecular weights. Accordingly, in a third aspect of the invention: there is provided the use of a hydrocracking catalyst according to the first aspect of the invention in the hydrocracking reaction of a hydrocarbon feedstock.

The hydrocarbon feedstock may be various heavy mineral oils or synthetic oils or their mixed distillates, such as straight run gas oil (straight run gas oil), vacuum gas oil (vacuum gas oil), demetalized oils (demetalized oils), atmospheric residues (atmospheric residues), deasphalted vacuum residues (deasphalted vacuum residues), coker distillates (coker distillates), catalytic cracker distillates (cat distillates), shale oils (shell oils), tar sand oils (tar sand oils), coal liquefied oils (coal liquids), etc. Particularly, the catalyst provided by the invention is particularly suitable for hydrocracking heavy and poor distillate oil to produce a hydrocracking process of middle distillate oil with the distillation range of 149-371 ℃, particularly 180-370 ℃.

In the application of the hydrocracking catalyst provided by the invention in the hydrocracking reaction of the hydrocarbon raw material, the hydrocracking catalyst is preferably presulfided by sulfur, hydrogen sulfide or a sulfur-containing raw material at the temperature of 140-370 ℃ in the presence of hydrogen before the hydrocracking catalyst is used, and the presulfiding can be carried out outside the reactor or in-situ sulfidation in the reactor to convert the catalyst into a sulfide type.

When the catalyst provided by the invention is used for distillate oil hydrocracking, the catalyst can be used under the conventional hydrocracking process conditions, for example, the hydrocracking reaction conditions are as follows: inverse directionThe temperature is 200-650 ℃, preferably 300-510 ℃; the reaction pressure is 3-24 MPa, preferably 4-15 MPa; the liquid hourly space velocity is 0.1-10 hours^-1Preferably 0.2 to 5 hours^-1(ii) a The volume ratio of the hydrogen to the oil is 100-5000, preferably 200-1000.

The hydrocracking reaction apparatus may be any reaction apparatus sufficient to allow the hydrocarbon feedstock to react with the catalyst under hydrogenation reaction conditions, and may be, for example, a fixed bed reactor, a moving bed reactor, an ebullating bed reactor or a slurry bed reactor.

The present invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.

The pore volume and the specific surface area of the molecular sieve are measured by a static low-temperature adsorption capacity method (by adopting a national standard GB/T5816-1995 method) by adopting an ASAP 2400 model automatic adsorption instrument of American micromeritics instruments, and the specific method comprises the following steps: vacuumizing and degassing at 250 deg.C and 1.33Pa for 4 hr, contacting with nitrogen as adsorbate at-196 deg.C, and statically reaching adsorption balance; and calculating the nitrogen adsorption amount of the adsorbent according to the difference between the nitrogen gas inflow and the nitrogen gas remaining in the gas phase after adsorption, calculating the pore size distribution by using a BJH (British Ribose) formula, and calculating the specific surface area and the pore volume by using a BET (BET) formula.

The crystal structure of the molecular sieve is determined by an X-ray diffractometer D5005 of Siemens Germany, and the method is in an industry standard SH/T0339-92. The experimental conditions are as follows: cu target, Ka radiation, solid detector, tube voltage 40kV, tube current 40mA, step scanning, step width of 0.02 degrees, prefabrication time of 2s and scanning range of 5-70 degrees. The diffraction angle position refers to the 2 theta angle value of the highest peak value of the diffraction peak.

The silicon content, aluminum content, phosphorus content and sodium content of the molecular sieve are measured by a 3271E type X-ray fluorescence spectrometer of Nippon science and Motor industry Co., Ltd, and the measuring method comprises the following steps: tabletting and forming a powder sample, carrying out rhodium target, detecting the spectral line intensity of each element by a scintillation counter and a proportional counter under the laser voltage of 50kV and the laser current of 50mA, and carrying out quantitative and semi-quantitative analysis on the element content by an external standard method.

Preparation examples 1 to 2 are provided to illustrate the preparation method of the phosphorus-containing high-silicon molecular sieve of the present invention.

Preparation of example 1

Taking phosphorus-containing molecular sieve (USY produced by China petrochemical catalyst Chang Ling division, with unit cell constant of 2.456nm and specific surface area of 672 m)²Per g, pore volume of 0.357ml/g, Na₂O content 1.44 wt.%, P₂O₅Content 1.37 wt%) was put into a hydrothermal kettle, 100% steam was introduced, and the molecular sieve material after hydrothermal treatment was taken out after hydrothermal treatment at 560 ℃ and 0.8MPa for 3 hours.

Taking 50g (dry basis) of the obtained molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain first slurry, heating the first slurry to 80 ℃, adding 2.0mol/L sulfuric acid solution, stopping adding acid when the pH value of the first slurry after acid addition is detected to be 2.8, then carrying out constant-temperature reaction for 4 hours, and filtering to obtain 40g of first solid product.

And adding 400ml of deionized water into the first solid product, stirring and pulping to obtain second slurry, and heating the second slurry to 80 ℃. Based on 1L of the second slurry, H⁺Adding 2mol/L sulfuric acid solution into the second slurry at a speed of 5mol/h, stopping adding acid when the pH value of the second slurry after acid addition is detected to be 1.4, then reacting at a constant temperature for 3h, filtering, collecting a second solid product, and drying at 180 ℃ for 3h to obtain the phosphorus-containing silicon-aluminum molecular sieve Y-1, wherein an XRD spectrogram of the phosphorus-containing silicon-aluminum molecular sieve Y-1 is shown in figure 1, and can be seen, wherein the diffraction angle position of a first strong peak is 6.1-6.8 degrees, the diffraction angle position of a second strong peak is 10.2-10.7 degrees, the diffraction angle position of a third strong peak is 15.8-16.5 degrees, the diffraction angle position of a fourth strong peak is 20.8-21.4 degrees, and the diffraction angle position of a fifth strong peak is 12.1-12.6 degrees. Other properties are shown in table 1.

Preparation of example 2

A high silicon molecular sieve was prepared as in preparative example 1, except that the second acid solution was added at a rate of 15 mol/h. The prepared molecular sieve Y-2 has an XRD spectrogram shown in figure 1, and can be seen, wherein the diffraction angle position of a first intensity peak is 6.1-6.8 degrees, the diffraction angle position of a second intensity peak is 10.2-10.7 degrees, the diffraction angle position of a third intensity peak is 15.8-16.5 degrees, the diffraction angle position of a fourth intensity peak is 20.8-21.4 degrees, and the diffraction angle position of a fifth intensity peak is 12.1-12.6 degrees. Other properties are shown in table 1.

Comparative examples 1 to 3 are prepared to illustrate the preparation of phosphorus-containing molecular sieves different from the present invention.

Preparation of comparative example 1

The molecular sieve of the preparation comparative example is a PSRY molecular sieve, the preparation method refers to CN1088407C example 1, the PSRY molecular sieve is named as DY-1, and an XRD spectrogram is shown in figure 1, so that the diffraction angle position of a first strong peak is 6.0-6.5 degrees, the diffraction angle position of a second strong peak is 15.7-16.2 degrees, the diffraction angle position of a third strong peak is 23.5-24.0 degrees, the diffraction angle position of a fourth strong peak is 20.4-20.7 degrees, the diffraction angle position of a fifth strong peak is 10.0-10.5 degrees, and the preparation method is different from the phosphorus-containing high-silicon molecular sieve of the preparation example 1. Other properties are shown in table 1.

Preparation of comparative example 2

Taking phosphorus-free HY molecular sieve (product name HY, unit cell constant 2.465nm, specific surface area 580m, produced by Zhongshiedian catalyst Chang Ling division Co., Ltd.)²Per g, pore volume of 0.33ml/g, Na₂0.3 wt.% of O, Al₂O₃Content of 22 wt%) was put into a hydrothermal kettle, 100% steam was introduced, and the molecular sieve material after hydrothermal treatment was taken out after hydrothermal treatment at 500 ℃ and 2.0MPa for 1 hour.

Taking 80g (dry basis) of the obtained molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain first slurry, heating the first slurry to 80 ℃, adding 1.0mol/L sulfuric acid solution, stopping adding acid when the pH value of the first slurry after acid addition is detected to be 3.0, then carrying out constant temperature reaction for 4 hours, and filtering to obtain 65g of first solid product.

Adding 600ml of deionized water into the first solid product, stirring and pulping to obtain second slurry, and heating the second slurry to 80 ℃. Based on 1L of the second slurry, H⁺Adding 1.0mol/L phosphoric acid solution into the second slurry at a speed of 2mol/h, stopping adding acid when the pH value of the acid-added second slurry is detected, reacting at constant temperature for 3h, filtering, collecting the second solid product, and drying at 180 ℃ for 3h to obtain molecular sieve DY-2 with XRD spectrogram such asAs shown in FIG. 1, it can be seen that the diffraction angle position of the first intensity peak is 5.5 to 6.2 °, the diffraction angle position of the second intensity peak is 15.7 to 16.2 °, the diffraction angle position of the third intensity peak is 10.0 to 10.5 °, the diffraction angle position of the fourth intensity peak is 11.8 to 12.2 °, and the diffraction angle position of the fifth intensity peak is 20.3 to 20.7 °. Other properties are shown in table 1.

Preparation of comparative example 3

500g of phosphorus-containing molecular sieve (same as example 1) is put into a hydrothermal kettle, 100 percent of water vapor is introduced, and after hydrothermal treatment is carried out for 3 hours at 560 ℃ and 0.8MPa, the molecular sieve material after the hydrothermal treatment is taken out.

Taking 60g (dry basis) of the molecular sieve material subjected to the hydrothermal treatment, adding 500ml of deionized water, stirring and pulping to obtain first slurry, heating the first slurry to 90 ℃, adding 2.0mol/L sulfuric acid solution, stopping adding acid when the pH value of the first slurry after acid addition is detected to be 2.5, then reacting at a constant temperature for 4 hours, filtering to obtain 60g of first solid product, and drying at 180 ℃ for 3 hours to obtain the molecular sieve DY-3, wherein an XRD spectrogram of the molecular sieve DY-3 is shown in figure 1, as can be seen, the diffraction angle position of a first strong peak is 15.7-16.0 degrees, the diffraction angle position of a second strong peak is 6.0-6.5 degrees, the diffraction angle position of a third strong peak is 23.7-24.3 degrees, the diffraction angle position of a fourth strong peak is 11.5-12.0 degrees, the diffraction angle position of a fifth strong peak is 10.0-10.5 degrees, and the molecular sieve is different from the phosphorus-containing high silicon molecular sieve in preparation example 1. Other properties are shown in table 1.

TABLE 1

Examples 1 to 6 are provided to illustrate the preparation method of the hydrocracking catalyst provided by the present invention. Comparative examples 1-3 are presented to illustrate catalysts prepared using different molecular sieves than the present invention.

Example 1

Mixing 65g Y-1 molecular sieve (dry basis weight, obtained by calcining at 700 deg.C for 1 hr), 29g pseudoboehmite (trade name PB90, produced by Zhonghua catalyst Changjin Co., Ltd.), and 20g MFI molecular sieve (ZSM-5, produced by Zhonghua catalyst Changjin Co., Ltd., specific surface area 325 m)²(g), the ratio of framework silicon to aluminum is 70, the pore volume is 0.31mL/g, and the dry basis is 76%), extruding into a trilobal strip with the circumscribed circle diameter of 1.6 mm, drying at 120 ℃ for 3h, and roasting at 600 ℃ for 3h to obtain the carrier CS-1. After cooling to room temperature, 100g of CS-1 carrier was immersed in 70mL of aqueous solution containing 34.65g of ammonium metatungstate (82 wt% tungsten oxide, product of beijing new photochemical reagent plant) and 24.37g of nickel nitrate (27.85 wt% nickel oxide, product of beijing new photochemical reagent plant), dried at 120 ℃ for 3h, and calcined at 480 ℃ for 4h, to obtain the hydrocracking catalyst prepared in this example, the composition of which is shown in table 2.

Example 2

A catalyst was prepared as in example 1, except that Y-2 was used as the molecular sieve.

Example 3

Mixing 90g Y-1 dry basis molecular sieve, 7.1g pseudoboehmite (product name PB90, dry basis 70 wt%) and 6.6g MFI molecular sieve (product name ZRP, specific surface area 305m, manufactured by Changling catalyst factory, China petrochemical catalyst division)²(g), the ratio of framework silicon to aluminum is 40, the pore volume is 0.36mL/g, and the dry basis is 76 wt%), extruding into a trilobal strip with the circumscribed circle diameter of 1.6 mm, drying at 120 ℃ for 3h, and roasting at 600 ℃ for 3h to obtain the carrier CS-3. After cooling to room temperature, 100g of CS-3 carrier was immersed in 45mL of an aqueous solution containing 13.86g of ammonium metatungstate (82 wt% tungsten oxide, product of the beijing new photochemical agent factory) and 8.16g of nickel nitrate (27.85 wt% nickel oxide, product of the beijing new photochemical agent factory), dried at 120 ℃ for 3 hours, and calcined at 480 ℃ for 4 hours, to obtain the hydrocracking catalyst prepared in this example, the composition of which is shown in table 2.

Example 4

20g Y-1 g of a dry-based molecular sieve, 7.1g of pseudoboehmite (product name PB90, dry basis 70 wt%) and 98.7g of MFI molecular sieve (product name ZSM-5, specific surface area 285m, manufactured by Changling catalyst works, China petrochemical catalyst industries, Ltd.)²(g), framework silica-alumina ratio 33, pore volume 0.29mL/g, dry basis 76 wt.%) and extruded into trilobal strips with circumscribed circle diameter of 1.6 mm, dried at 120 ℃ for 3h, and dried at 60 DEG CRoasting at 0 deg.c for 3 hr to obtain carrier CS-4. After cooling to room temperature, 100g of CS-5 carrier was immersed in 74g of an aqueous solution containing 74g of ammonium metatungstate (82 wt% tungsten oxide, product of the new photochemical reagent plant of tokyo, 27.85 wt% nickel nitrate) and 43g of nickel nitrate (70 mL of aqueous solution), dried at 120 ℃ for 3 hours, and calcined at 480 ℃ for 4 hours, to obtain the hydrocracking catalyst prepared in this example, the composition of which is shown in table 2.

Example 5

15g Y-1 g of a dry molecular sieve, 114g of pseudoboehmite (product of Zhongpetrochemical catalyst from Changling catalyst division, trade name PB90, dry basis 70 wt.%) and 6.6g of a ZSM-5 molecular sieve (product of Zhongpetrochemical catalyst division, Changling catalyst plant, specific surface area 285 m)²(g), the ratio of framework silicon to aluminum is 33, the pore volume is 0.29mL/g, and the dry basis is 75 wt%), extruding into a trilobal strip with the circumscribed circle diameter of 1.6 mm, drying at 120 ℃ for 3h, and roasting at 600 ℃ for 3h to obtain the carrier CS-5. After cooling to room temperature, 100g of CS-5 carrier was immersed in 69g of 80mL of aqueous solution containing ammonium metatungstate (82 wt% tungsten oxide, product of the beijing new photochemical reagent plant), 17g of nickel nitrate (27.85 wt% nickel oxide, product of the beijing new photochemical reagent plant), dried at 120 ℃ for 3 hours, and calcined at 480 ℃ for 4 hours, to obtain the hydrocracking catalyst prepared in this example, the composition of which is shown in table 2.

Example 6

5g Y-1 dry basis molecular sieve, 129g of pseudoboehmite (product of Zhongpetrochemical catalyst Changjingtie company, trade name PB90, dry basis 70 wt.%) and 6.6g of ZSM-5 molecular sieve (product of Zhongpetrochemical catalyst Changjingtie catalyst factory, specific surface area 285m²(g), the ratio of framework silicon to aluminum is 33, the pore volume is 0.29mL/g, and the dry basis is 75 wt%), extruding into a trilobal strip with the circumscribed circle diameter of 1.6 mm, drying at 120 ℃ for 3h, and roasting at 600 ℃ for 3h to obtain the carrier CS-6. After cooling to room temperature, 100g of CS-6 carrier was immersed in 95mL aqueous solution containing 29g of molybdenum trioxide (produced by Taoyang gold Touchu Mo Co., Ltd.), 67g of cobalt nitrate (produced by Beijing New photochemical reagent factory, cobalt oxide content 27.85 wt%), and 11.8g of phosphoric acid (produced by Beijing chemical reagent factory, purity 85%), dried at 120 ℃ for 3h, and calcined at 480 ℃ for 4h to obtain the hydrocracking catalyst prepared in the present example, the composition of which is shown in Table2。

Test examples

The test examples were used to test the catalytic activity of the catalysts of examples 1 to 3 and comparative examples 1 to 3 for hydrocracking reactions.

The hydrocracking activity of the catalyst was evaluated on a small fixed bed hydrocracking unit using n-octane containing 5.61% of tetralin and 0.29% of pyridine as the starting material, with a catalyst loading of 0.2 ml, a reaction temperature of 310 ℃, a reaction pressure of 4.0MPa, a hydrogen-oil molar ratio of 25, and a liquid hourly space velocity of 30h^-1After the reaction feed had stabilized for 4h, the catalyst activity was represented by the percent of n-decane converted in the product composition and the selectivity of the catalyst by the percent of iso-decane, the results of which are shown in Table 2.

Catalyst and process for preparing same	Conversion (%)	Selectivity is
			Example 1	65.2	35.3
Example 2	60.3	32.3
			Example 3	63.1	33.8
Comparative example 1	43.2	21.8
			Comparative example 2	55.0	26.3
Comparative example 3	51.2	20.4

It can be seen from table 2 that under the same reaction conditions, compared with the molecular sieve prepared by the existing method, the catalyst containing the phosphorus-containing silicon-aluminum molecular sieve provided by the invention has the advantages that the catalytic activity is improved by more than 20% and the selectivity is improved by more than 10% under the high nitrogen condition.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.