阅读说明：本技术 一种加氢脱氮催化剂及其制备方法与应用 (Hydrodenitrogenation catalyst and preparation method and application thereof ) 是由 肖洁 于 2020-06-04 设计创作，主要内容包括：本发明一方面公开了一种加氢脱氮催化剂的制备方法,包括以下步骤：蒙脱石水悬浮液制备；蒙脱石功能化和扩孔；离子液体制备纳米金属硫化物以及蒙脱石复合材料的制备。本发明还公开了上述制备方法制得的催化剂以及该催化剂在渣油加氢脱氮中的应用。本发明采用离子液体扩孔蒙脱石材料,进一步采用离子液体功能化活性金属,并负载在改性的蒙脱石,用于渣油加氢精制催化剂。所述催化剂孔结构和酸性分布有机地相互配合,孔道畅通,催化剂有效活性表面极高,提高了催化剂的整体性能,具有优异的催化加氢脱氮性能,且不易积碳。(The invention discloses a preparation method of a hydrodenitrogenation catalyst, which comprises the following steps: preparing montmorillonite water suspension; carrying out montmorillonite functionalization and hole expansion; the ionic liquid is used for preparing nano metal sulfide and montmorillonite composite material. The invention also discloses the catalyst prepared by the preparation method and the application of the catalyst in the residual oil hydrodenitrogenation. The invention adopts an ionic liquid chambering montmorillonite material, further adopts ionic liquid functionalized active metal, and is loaded on modified montmorillonite to be used as a residual oil hydrofining catalyst. The pore structure and the acidity distribution of the catalyst are organically matched with each other, the pore channel is smooth, the effective active surface of the catalyst is extremely high, the overall performance of the catalyst is improved, the catalyst has excellent catalytic hydrodenitrogenation performance, and carbon deposition is not easy to generate.)

1. The preparation method of the hydrodenitrogenation catalyst is characterized by comprising the following steps of:

1) dispersing montmorillonite in water, standing, and removing precipitate to obtain montmorillonite water suspension;

2) adding ionic liquid and nonionic surfactant into the montmorillonite water suspension, stirring, standing, and centrifuging to obtain white solid product; drying and calcining the white solid product to obtain a montmorillonite carrier;

3) adding a metal source and a sulfur source into water, and reacting at 60-85 ℃ for 15-20h to obtain a mixed solution;

4) adding an ionic liquid and a reducing agent into the mixed solution to prepare an initial reaction mixture;

5) carrying out ultrasonic treatment on the initial reaction mixture to obtain a nano metal sulfide dispersion liquid;

6) dipping the nano metal sulfide dispersion liquid on the surface of the montmorillonite carrier by adopting an isometric dipping method, standing, and then transferring the nano metal sulfide dispersion liquid into a high-pressure synthesis kettle for crystallization;

7) and after crystallization is finished, separating a solid product to obtain the catalyst.

2. The method of claim 1, wherein the metal source is any two or three of a tungsten source, a nickel source, and a copper source; the sulfur source is one or two of ammonium sulfide, sodium sulfide, potassium sulfide and thiourea.

3. The method of claim 2, wherein the tungsten source is a sulfur tungsten compound, the nickel source is a soluble nickel-containing sulfate or nitrate, and the copper source is a soluble copper-containing sulfate or nitrate.

4. The method for producing a hydrodenitrogenation catalyst according to claim 1, wherein in step 2), the ionic liquid is added in an amount of 0.5 to 5 wt% based on the montmorillonite.

5. The method of claim 1, wherein the ionic liquid contains one or more cations selected from the group consisting of alkyl imidazole and quaternary ammonium ions, and anions selected from the group consisting of halogen ions, tetrafluoroborate, hexafluorophosphate, borate, phosphate, carbonate, and hydroxide.

6. The method for preparing the hydrodenitrogenation catalyst according to claim 1, wherein in the step 2), the nonionic surfactant is one or two of tween 80, polyoxyethylene lauryl ether and polyoxyethylene octanol, and the molar ratio of the nonionic surfactant to the ionic liquid is 1:1-1: 5.

7. The method of claim 1, wherein the reducing agent is one or both of sodium borohydride and hydroxylamine hydrochloride.

8. The method for preparing a hydrodenitrogenation catalyst according to any one of claims 1 to 7, wherein the crystallization conditions are: the crystallization temperature is 50-200 ℃, and the crystallization time is 10-120 h.

9. A hydrodenitrogenation catalyst obtained by the production method according to any one of claims 1 to 8.

10. Use of the catalyst according to claim 9 in hydrodenitrogenation reactions of resids.

Technical Field

The invention relates to the technical field of catalyst preparation, in particular to a hydrodenitrogenation catalyst suitable for a residual oil hydrodenitrogenation process and a preparation method and application thereof.

Background

The world petroleum resources are gradually reduced, the average consumption of diesel oil, gasoline and the like is gradually increased, the phenomena of heavy oil and poor oil of crude oil extracted from the world are gradually serious, the demand of light oil products in the social market is increased year by year, so that the technology for lightening the residual oil and the residual oil accounting for a large proportion of petroleum is more and more emphasized by people, and a large number of large petroleum companies in the world invest a large amount of manpower and material resources to develop and research the residual oil hydrogenation catalyst.

In the catalytic reaction process of residual oil hydrodenitrogenation, the hydrodenitrogenation reaction of the nitrogen-containing heterocyclic component must first completely hydrogenate and saturate the nitrogen-containing heterocyclic component, and then the nitrogen atoms can be removed. Therefore, the hydrodenitrogenation reaction requires a catalyst having a high hydrogenation activity. In addition, the hydrodenitrogenation catalyst needs to have not only good hydrogenation activity but also strong sulfur resistance.

The carrier material used by the existing residual oil hydrodenitrogenation catalyst is generally macroporous alumina and modified products thereof. CN109718751A and CN106669752A respectively disclose preparation methods of an alumina carrier for hydrodenitrogenation; CN103657736A discloses an activated carbon/alumina composite catalyst carrier and preparation and application thereof; however, the pores of the alumina carrier are mainly formed by accumulating particles, and the structural model of the alumina pores is in a network type, so that the phase change is easy to occur, and further sintering is easy to occur.

The montmorillonite crystal structure is formed by closely packing aluminum oxygen octahedrons and silicon oxygen tetrahedrons, and is mainly a three-layer structure formed by connecting two silicon oxygen tetrahedrons and one aluminum oxygen octahedron through covalent bonds, so that the arrangement of internal lattices is highly ordered. The special crystal structure makes the material have the characteristics of adsorptivity, water absorbability, cohesiveness, exchangeability, dispersibility and the like. Therefore, it can be optimized and modified, and the modified montmorillonite will have interlaminar domains, which is a very good chemical reaction site. At present, reports of using montmorillonite as a hydrogenation catalyst carrier are very rare.

Disclosure of Invention

The invention aims to provide a hydrodenitrogenation catalyst taking montmorillonite as a carrier and a preparation method thereof aiming at the requirements of the existing hydrodenitrogenation desulfurization technology.

In order to achieve the above object, the present invention provides a method for preparing a hydrodenitrogenation catalyst, comprising the steps of:

1) dispersing montmorillonite in water, standing, and removing precipitate to obtain montmorillonite water suspension;

2) adding ionic liquid and nonionic surfactant into the montmorillonite water suspension, stirring, standing, and centrifuging to obtain white solid product; drying and calcining the white solid product to obtain a montmorillonite carrier;

3) adding a metal source and a sulfur source into water, and reacting at 60-85 ℃ for 15-20h to obtain a mixed solution;

4) adding an ionic liquid and a reducing agent into the mixed solution to prepare an initial reaction mixture;

5) carrying out ultrasonic treatment on the initial reaction mixture to obtain a nano metal sulfide dispersion liquid;

6) dipping the nano metal sulfide dispersion liquid on the surface of the montmorillonite carrier by adopting an isometric dipping method, standing, and then transferring the montmorillonite carrier to a high-pressure synthesis kettle for crystallization;

7) and after crystallization is finished, separating a solid product to obtain the catalyst.

Optionally, according to the preparation method of the hydrodenitrogenation catalyst, the metal source is any two or three of a tungsten source, a nickel source and a copper source; the sulfur source is one or two of ammonium sulfide, sodium sulfide, potassium sulfide and thiourea.

Optionally, according to the preparation method of the hydrodenitrogenation catalyst, the tungsten source is a sulfur-tungsten compound, the nickel source is soluble nickel-containing sulfate or nitrate, and the copper source is soluble copper-containing sulfate or nitrate.

Alternatively, according to the preparation method of the hydrodenitrogenation catalyst of the present invention, in step 2), the ionic liquid is added in an amount of 0.5 to 5 wt% of the montmorillonite.

Optionally, according to the preparation method of the hydrodenitrogenation catalyst, in the ionic liquid, the cation is one or two of alkyl imidazole and quaternary ammonium ion, and the anion is one or more of halogen ion, tetrafluoroborate, hexafluorophosphate, borate, phosphate, carbonate and hydroxide.

Alternatively, according to the preparation method of the hydrodenitrogenation catalyst, in the step 2), the nonionic surfactant is one or two of tween 80, polyoxyethylene lauryl ether and polyoxyethylene octanol, and the molar ratio of the nonionic surfactant to the ionic liquid is 1: 1-1:5.

Alternatively, according to the preparation method of the hydrodenitrogenation catalyst, the reducing agent is one or both of sodium borohydride and hydroxylamine hydrochloride.

Alternatively, according to the preparation method of the hydrodenitrogenation catalyst, the crystallization conditions are as follows: the crystallization temperature is 50-200 ℃, and the crystallization time is 10-120 h.

On the other hand, the invention also provides a hydrodenitrogenation catalyst obtained by the preparation method of the hydrodenitrogenation catalyst.

In another aspect, the invention also provides the application of the catalyst in the residual oil hydrodenitrogenation reaction.

The invention has the beneficial effects that:

the invention adopts an ionic liquid pore-enlarging montmorillonite material, further adopts ionic liquid functionalized active metal, and loads modified montmorillonite for a residual oil hydrofining catalyst. The prepared catalyst has the advantages that the pore structure and the acidity distribution of the catalyst are organically matched with each other by adopting the ionic liquid, the pore channel is smooth, the effective active surface of the catalyst is extremely high, the overall performance of the catalyst is improved, the catalyst has high catalytic denitrification activity, and carbon deposition is not easy to generate.

Detailed Description

The invention is further described below with reference to specific embodiments.

In one aspect, the present invention provides a method for preparing a hydrodenitrogenation catalyst, comprising the steps of:

step 1): dispersing montmorillonite in water, standing, and removing precipitate to obtain montmorillonite water suspension;

step 2): adding ionic liquid and nonionic surfactant into the montmorillonite water suspension, stirring, standing, and centrifuging to obtain white solid product; drying and calcining the white solid product to obtain a montmorillonite carrier;

step 3): adding a metal source and a sulfur source into water, and reacting at 60-85 ℃ for 15-20h to obtain a mixed solution;

step 4): adding an ionic liquid and a reducing agent into the mixed solution to prepare an initial reaction mixture;

step 5): carrying out ultrasonic treatment on the initial reaction mixture to obtain a nano metal sulfide dispersion liquid;

step 6): dipping the nano metal sulfide dispersion liquid on the surface of the montmorillonite carrier by adopting an isometric dipping method, standing, and then transferring the montmorillonite carrier to a high-pressure synthesis kettle for crystallization;

step 7): and after crystallization is finished, separating a solid product to obtain the catalyst.

In the preparation method, the ionic liquid and the nonionic surfactant are used, wherein the ionic liquid is a liquid consisting of organic cations and inorganic anions, is a novel green solvent and has a wide application prospect. Ionic liquids have many superior properties compared to traditional solvents: the product has good thermal stability, chemical stability and low volatility; the catalyst has high solubility to various organic and inorganic compounds, has double functions of a solvent and a catalyst, and can be used as a solvent for a plurality of chemical reactions or a catalyst carrier required in catalytic reactions; the polarity of the ionic liquid can be regulated, a two-phase or multi-phase system can be formed, and the ionic liquid is suitable for being used as a separation solvent or forming a new reaction separation coupling system; the ionic liquid has designability, and the property of the ionic liquid can be changed according to the types of the anions and the cations. In the application, the hydrophilic and hydrophobic properties among montmorillonite layers can be adjusted by utilizing the ionic liquid, so that the nano particles are more loosely, continuously and uniformly fixed on the surface of the montmorillonite, a loose pore structure is presented, the activity and the reaction space of nano metal sulfide are favorably increased, and the hydrogenation effect of the catalyst is improved. In addition, the ionic liquid is matched with the nonionic surfactant for use, so that the interlayer spacing and the pore volume of the montmorillonite can be increased and regulated, and the thermal stability of the montmorillonite is improved.

Specifically, in the above step 1), the concentration of the aqueous suspension of montmorillonite is 0.5 to 1.5%, preferably 1%. For example, 1.0g of purified montmorillonite is weighed, dispersed in 100mL of deionized water, stirred electrically for 5 hours, and left to stand for 12 to 24 hours. Then removing the sediment to obtain the montmorillonite water suspension with the mass fraction of 1 percent.

In the above step 2), it is preferable that the ionic liquid and the nonionic surfactant are dropwise added to the aqueous suspension of montmorillonite, and electrically stirred at 50 ℃ for 5 hours, and left to stand for aging overnight, whereby a white solid deposit is formed at the bottom of the container and a pale yellow transparent liquid is formed at the upper part. The product was obtained as a white solid by centrifugation. Washing the white product with ethanol for three times, then drying in vacuum, and finally calcining at the high temperature of 300-800 ℃ to obtain the functionalized and expanded montmorillonite carrier.

Preferably, in the ionic liquid, the cation is one or two of alkyl imidazole and quaternary ammonium ion, the anion is one or more of halogen ion, tetrafluoroborate, hexafluorophosphate, borate, phosphate, carbonate and hydroxide, and the ionic liquid may be, for example, 1-propyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium bromide, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium hexafluorophosphate, etc. The nonionic surfactant is one or two of tween 80, polyoxyethylene lauryl ether and polyoxyethylene octanol.

Further preferably, in step 2), the ionic liquid is added in an amount of 0.5 to 5% by weight, i.e. 0.5 to 5% by weight, of the montmorillonite, and may be, for example, 1%, 2%, 3%, 4% by weight. The molar ratio of the nonionic surfactant to the ionic liquid is 1:1-1:5, for example, 1:1, 1:3, 1: 5.

In the step 3), the metal source is any two or three of a tungsten (W) source, a nickel (Ni) source and a copper (Cu) source; the sulfur source is one or two of ammonium sulfide, sodium sulfide, potassium sulfide and thiourea. Preferably, the tungsten source is a sulfur tungsten compound, more preferably, the sulfur tungsten compound source is a dithiotungstate and a tetrathiotungstic acidOne or two of the salts, the cation of which is Na⁺、K⁺One or two of (a); and the molar concentration of the sulfur-tungsten compound is 0.05-2 mol/l. Also preferably, the nickel source is a soluble nickel-containing sulfate or nitrate and the copper source is a soluble copper-containing sulfate or nitrate.

At present, the metal components used by the hydrogenation catalyst are mostly VIB, VIIB and VIII groups of the periodic table of elements, and the metal elements of other groups in the periodic table of elements are rarely related, in fact, copper (Cu) elements of other groups in the periodic table of elements, such as IB groups, still remain high-activity catalysts for hydrogenation of heavy residual oil, and particularly, the activity of the catalysts is greatly enhanced if the catalysts are combined with other catalysts for use. Moreover, the cost of the copper (Cu) compound used as the catalyst is greatly reduced compared with that of the molybdenum (Mo), cobalt (Co) and other series catalysts

In the catalyst, the metal active component contains at least two of the VI B, VIII and IB metal components, and the compound use of the metals not only improves the catalyst activity and increases the residual oil conversion rate, but also reduces the catalyst cost when cheap copper is used.

In addition, one or more elements with positive and negative electric properties are introduced into the catalyst, so that the catalyst has the required average electronegativity, the pore structure is changed, the activity of demetallization, N removal and S removal of the catalyst is high, and the catalyst has a good carbon deposit resistance effect.

In the step 4), the reducing agent is one or two of sodium borohydride and hydroxylamine hydrochloride. Further preferably, in this step, the molar ratio of the added ionic liquid to the reducing agent is 0.1-20:1, and may be, for example, 0.5:1, 1:1, 5:1, 10:1, 15: 1.

The residual oil hydrogenation reaction is carried out on a catalyst, belongs to heterogeneous catalytic reaction and has chemical adsorption effect. In the residual oil hydrogenation reaction, the catalyst deactivation process is divided into three periods: initial rapid deactivation by carbon deposition, intermediate slow deactivation by metal sulfides, and final rapid deactivation by catalyst pore plugging. Therefore, the acid strength of the residual oil hydrogenation catalyst must be moderate, so that the impurity removal rate of the catalyst can be ensured, the residual oil molecules are not excessively cracked, and the hydrogen consumption of a hydrogenation device is lower. In the application, the particle size distribution of the active metal can be optimized by adjusting the use amounts of the metal sources (active metals) in different ionic liquids and catalysts, the acid distribution and the metal distribution can be adjusted in a targeted manner, and the content of the active components can be increased.

In the step 5), before the ultrasonic treatment, ethanol may be added to the initial reaction mixture to disperse the mixture, so as to improve the effect of the ultrasonic treatment; the volume of ethanol added may be equal to the volume of the initial reaction mixture. And carrying out ultrasonic treatment for 3-8 minutes.

In the step 6), the nano metal sulfide dispersion liquid is dipped on the surface of the montmorillonite carrier by an isometric dipping method, then is kept stand for 5-15h at room temperature and then is transferred to a high-pressure synthesis kettle for crystallization. Preferably, the crystallization is carried out under the condition that the pH value is 5.0-11.0, the crystallization temperature is 50-200 ℃ (preferably 60-180 ℃, such as 80 ℃, 100 ℃, 120 ℃, 150 ℃, 170 ℃), and the crystallization time is 10-120h (preferably 20-100h, such as 30h, 50h, 70h, 90 h). In this step, for example, ammonia, NaOH, KOH, HCl, HNO can be used₃And (3) adjusting the pH value of the reaction system of the high-pressure synthesis kettle, preferably selecting ammonia water as an alkali source and nitric acid as an acid source.

In the step 7), the process of separating the solid product comprises the following steps: filtering, washing with deionized water and drying to obtain the product. The separation process is a conventional operation in the prior art, and specific operation steps and parameters are not described herein.

On the other hand, the invention also provides a hydrodenitrogenation catalyst obtained by the preparation method of the hydrodenitrogenation catalyst. The specific surface area of the prepared catalyst is 200-450m²The pore volume is 0.6-1.8 ml/g, and the pore diameter is 10-35 nm.

In another aspect, the invention also provides the application of the catalyst in hydrodenitrogenation reaction of inferior wax oil and residual oil. The catalyst shows excellent catalytic activity in hydrodenitrogenation, has good sulfur resistance and residual carbon resistance, and has wide application prospect in high-denitrification reaction of raw materials such as inferior wax oil, residual oil and the like.

To describe the invention in detail, the Applicant has used tungsten disulfide nickel copper/montmorillonite (WNiCuS)₂Montmorillonite) as an example, the preparation method of the hydrodenitrogenation catalyst of the present application is exemplified. It should be understood that the following specific examples are illustrative of specific implementations of the invention only and are not to be construed as limiting the scope of the invention.