阅读说明：本技术 一种加氢脱金属催化剂的制备方法 (Preparation method of hydrodemetallization catalyst ) 是由 凌凤香 季洪海 张会成 王少军 沈智奇 于 2019-03-13 设计创作，主要内容包括：本发明公开了一种加氢脱金属催化剂的制备方法,包括：(1)制备棒状氧化铝团簇体；(2)棒状氧化铝团簇体与拟薄水铝石混捏成型、干燥、焙烧,得到载体I；(3)将步骤(2)所得的载体I与碳酸氢铵、水混合后密封热处理,处理后物料经干燥、焙烧,得到载体II；(4)用含加氢活性组分的浸渍液浸渍步骤(3)载体II,载体经干燥、焙烧制得加氢脱金属催化剂。该方法制备的加氢脱金属催化剂孔道贯通且孔分布适宜,该催化剂用于重油加氢脱金属反应时,具有较高的加氢脱金属活性和活性稳定性及较高的加氢脱硫活性。(The invention discloses a preparation method of a hydrodemetallization catalyst, which comprises the following steps: (1) preparing a rod-shaped alumina cluster body; (2) mixing and kneading the rod-shaped alumina cluster body and pseudo-boehmite, molding, drying and roasting to obtain a carrier I; (3) mixing the carrier I obtained in the step (2) with ammonium bicarbonate and water, sealing, performing heat treatment, drying and roasting the treated material to obtain a carrier II; (4) and (3) dipping the carrier II in the step (3) by using dipping liquid containing hydrogenation active components, and drying and roasting the carrier to obtain the hydrodemetallization catalyst. The hydrodemetallization catalyst prepared by the method has through pore passages and proper pore distribution, and has higher hydrodemetallization activity, activity stability and hydrodesulfurization activity when being used for heavy oil hydrodemetallization reaction.)

1. A method for preparing a hydrodemetallization catalyst, comprising: (1) preparing a rod-shaped alumina cluster body; (2) mixing and kneading the rod-shaped alumina cluster body and pseudo-boehmite, molding, drying and roasting to obtain a carrier I; (3) mixing the carrier I obtained in the step (2) with ammonium bicarbonate and water, sealing, performing heat treatment, drying and roasting the treated material to obtain a carrier II; (4) and (3) dipping the carrier II in the step (3) by using dipping liquid containing hydrogenation active components, and drying and roasting the carrier to obtain the hydrodemetallization catalyst.

2. The method of claim 1, wherein: the rod-shaped alumina cluster body in the step (1) is prepared by adopting the following method: immersing alumina powder in ammonium bicarbonate water solution for sealing heat treatment, carrying out solid-liquid separation after the heat treatment, and drying solid-phase materials.

3. The method of claim 2, wherein: the mass ratio of the amount of the ammonium bicarbonate aqueous solution to the alumina powder is 5:1-10:1, and the mass concentration of the ammonium bicarbonate aqueous solution is 10% -20%.

4. The method of claim 2, wherein: the sealing heat treatment temperature is 120-160 ℃, and the treatment time is 4-8 hours.

5. The method of claim 1, wherein: the rod-shaped alumina cluster body in the step (1) is a cluster body structure formed by disordered and mutually staggered rod-shaped alumina, the outer diameter of the rod-shaped alumina cluster body is 5-20 mu m, rod-shaped alumina accounts for more than 85% of the rod-shaped alumina cluster body, the length of single rod-shaped alumina is 1-5 mu m, and the diameter of the single rod-shaped alumina is 100-300 nm.

6. The method of claim 1, wherein: the mass ratio of the rod-shaped alumina cluster body to the pseudo-boehmite in the step (2) is 1:5-1: 1.

7. The method of claim 1, wherein: the step (2) adopts the following mode: dipping a rod-shaped alumina cluster body by using a solution containing a modification element, drying, kneading with pseudo-boehmite, molding, drying and roasting to obtain a carrier I; the solution containing the modified elements is a solution containing phosphorus, boron, fluorine, silicon, alkali metal or alkaline earth metal elements, preferably a solution containing phosphorus or boron, the mass concentration of the solution calculated by the elements is 0.2-0.5%, and the using amount of the solution is the saturated water absorption amount of the rod-shaped alumina cluster.

8. The method of claim 1, wherein: the mass ratio of the ammonium bicarbonate to the carrier I in the step (3) is 1:1-2.5:1, and the mass ratio of the water to the carrier I is 5:1-8: 1.

9. The method of claim 1, wherein: the sealing heat treatment temperature in the step (3) is 120-160 ℃, and the treatment time is 4-8 hours.

10. The method of claim 1, wherein: the impregnation liquid containing the hydrogenation active component in the step (4) is a solution containing VIB group and/or VIII group metals, wherein the VIB group metals are selected from W, Mo or more, the VIII group metals are selected from Co or Ni or more, the content of the VIB group metals is 8-15g/100mL calculated by metal oxides, and the content of the VIII group metals is 2.5-4.0g/100mL calculated by metal oxides; the impregnation is carried out by adopting equal-volume impregnation or supersaturated impregnation.

Technical Field

The invention relates to the field of catalyst preparation, in particular to a preparation method of a hydrodemetallization catalyst.

Background

With the deterioration and heaviness of crude oil, the efficient conversion of heavy oil and the improvement of the yield of light oil products become an important trend in the development of oil refining technology. The residue fixed bed hydrogenation technology is an effective means for realizing the high-efficiency conversion of heavy oil. By adopting the technical route, the impurities such as metal, sulfur, nitrogen, carbon residue and the like in the residual oil can be effectively removed, high-quality feed is provided for catalytic cracking, and the strict environmental protection regulation requirements are met while the yield of light oil products is increased. During the processing of heavy oil, the metal compounds therein are decomposed, and the metal impurities are deposited on the inner and outer surfaces of the catalyst to block the pore channels, even cause the catalyst to be poisoned and deactivated, so that the metal impurities contained therein must be removed firstly during the catalytic cracking of heavy oil. The hydrodemetallization catalyst mainly removes metal impurities including nickel and vanadium in raw oil, so as to protect downstream catalysts from losing activity due to deposition of a large amount of metals.

At present, most of the industrialized Hydrodemetallization (HDM) catalysts are Ni-Mo/Al₂O₃Catalyst of which Al₂O₃The pore structure of the support can significantly affect its catalytic activity as well as its stability. The results of previous studies show that: suitable Al₂O₃The pore size distribution of the carrier can provide a proper diffusion rate of metal compounds, the existence of a certain proportion of super-large pores in the alumina carrier can promote the diffusion and deposition of macromolecular asphaltene molecules, reduce the blockage of coke deposition to orifices, and even under the condition of serious nickel and vanadium deposition, the large pores can also allow the macromolecules to pass through, thereby improving the stability of the catalyst.

CN101890372A discloses an alumina carrier and a preparation method thereof. The alumina carrier is aluminum hydroxide gel prepared by a fused salt super-solubilization micelle method as a raw material, and the gel contains a surfactant and hydrocarbon components, so that after molding and roasting, nano alumina particles formed by dehydrating polymerized aluminum hydroxide still have a rod-like basic structure and are randomly stacked into a frame structure. The process for preparing the macroporous alumina carrier by the technology is complex.

CN106268969A discloses a catalyst carrier, a preparation method thereof and a demetallization catalyst thereof. The catalyst carrier is formed by stacking a plurality of nano rod-shaped alumina monomers, the catalyst carrier is provided with open pore channels, the length of each nano rod-shaped alumina monomer is 100-500nm, and the diameter of each nano rod-shaped alumina monomer is 10-50 nm. The catalyst carrier is formed by stacking a plurality of nano-rod-shaped alumina monomers, the formed pore channel is large, and the catalyst carrier is favorable for the diffusion of macromolecules such as colloid, asphaltene and the like, but also has the defect of complex preparation process.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of a hydrodemetallization catalyst. The hydrodemetallization catalyst prepared by the method has through pore passages and proper pore distribution, and has higher hydrodemetallization activity, activity stability and hydrodesulfurization activity when being used for heavy oil hydrodemetallization reaction.

The preparation method of the hydrodemetallization catalyst comprises the following steps:

(1) preparing a rod-shaped alumina cluster body;

(2) mixing and kneading the rod-shaped alumina cluster body and pseudo-boehmite, molding, drying and roasting to obtain a carrier I;

(3) mixing the carrier I obtained in the step (2) with ammonium bicarbonate and water, sealing, performing heat treatment, drying and roasting the treated material to obtain a carrier II;

(4) and (3) dipping the carrier II in the step (3) by using dipping liquid containing hydrogenation active components, and drying and roasting the carrier to obtain the hydrodemetallization catalyst.

In the method of the invention, the rod-like alumina cluster body in the step (1) is prepared by the following method: immersing alumina powder in ammonium bicarbonate water solution for sealing heat treatment, carrying out solid-liquid separation after the heat treatment, and drying solid-phase materials. The alumina powder is gamma-alumina powder prepared according to the prior art or sold on the market. The preparation method is generally a method for roasting pseudo-boehmite, wherein the roasting temperature is 450-600 ℃, the roasting time is 4-8 hours, and the pseudo-boehmite can be prepared by a precipitation method, an aluminum alkoxide hydrolysis method, an inorganic salt sol-gel method, a hydrothermal method, a vapor deposition method and the like. The mass ratio of the amount of the ammonium bicarbonate aqueous solution to the alumina powder is 5:1-10:1, and the mass concentration of the ammonium bicarbonate aqueous solution is 10% -20%. The sealing heat treatment temperature is 120-160 ℃, and the treatment time is 4-8 hours. The solid-liquid separation can adopt modes of filtration, centrifugation and the like, and the solid-liquid separation process generally comprises a washing process.

In the method, the rod-shaped alumina cluster body in the step (1) is a cluster body structure formed by disordered and staggered rod-shaped alumina, the outer diameter of the rod-shaped alumina cluster body is 5-20 mu m, wherein the rod-shaped alumina accounts for more than 85% of the rod-shaped alumina cluster body, preferably more than 90%, the rest is spherical or ellipsoidal alumina, the length of a single rod-shaped alumina is 1-5 mu m, and the diameter is 100-300 nm.

In the method of the present invention, the pseudoboehmite described in the step (2) may be a pseudoboehmite prepared by any method, for example, prepared by a precipitation method, an aluminum alkoxide hydrolysis method, an inorganic salt sol-gel method, a hydrothermal method, a vapor deposition method, and the like.

In the method, the mass ratio of the rod-shaped alumina cluster body in the step (2) to the pseudo-boehmite is 1:5-1: 1.

In the method of the present invention, preferably, in the step (2), the rod-like alumina cluster is impregnated with a solution containing a modifying element and dried, and then kneaded with pseudo-boehmite to be molded, dried and calcined to obtain a carrier I; the solution containing the modified elements is a solution containing elements such as phosphorus, boron, fluorine, silicon, alkali metals, alkaline earth metals and the like, preferably a solution containing phosphorus or boron, the mass concentration of the solution calculated by the elements is 0.2-0.5%, and the using amount of the solution is the saturated water absorption amount of the rod-shaped alumina cluster bodies.

In the method of the invention, the kneading molding in the step (2) is carried out by adopting the conventional method in the field, and in the molding process, the conventional molding auxiliary agent, such as one or more of peptizer, extrusion assistant and the like, can be added according to the requirement. The peptizing agent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid and the like; the extrusion aid is sesbania powder.

In the method of the invention, the drying condition in the step (2) is drying at 80-160 ℃ for 6-10 hours, and the roasting is roasting at 450-750 ℃ for 4-8 hours.

In the method, the mass ratio of the ammonium bicarbonate to the carrier I in the step (3) is 1:1-2.5:1, the mass ratio of the water to the carrier I is 5:1-8:1, the sealing heat treatment temperature is 120-160 ℃, and the treatment time is 4-8 hours. The drying temperature is 80-160 ℃, the drying time is 6-10 hours, and the roasting is carried out for 4-8 hours at the temperature of 450-750 ℃.

In the method, the impregnation liquid containing the hydrogenation active component in the step (4) is a solution containing VIB group and/or VIII group metals, wherein the VIB group metal is selected from one or more of W, Mo, the VIII group metal is selected from one or more of Co and Ni, the content of the VIB group metal is 8-15g/100mL calculated by metal oxides, the content of the VIII group metal is 2.5-4.0g/100mL calculated by metal oxides, and equal-volume impregnation or supersaturated impregnation can be adopted during impregnation. The drying temperature is 80-160 ℃, the drying time is 6-10 hours, and the roasting is 4-8 hours at the temperature of 450-550 ℃.

Compared with the prior art, the invention has the following advantages:

(1) the alumina carrier for the hydrodemetallization catalyst contains micron-sized rod-shaped alumina clusters, the rod-shaped alumina clusters are integrally dispersed in the carrier, rod-shaped aluminas in the rod-shaped alumina clusters are staggered, the pore structure of the alumina carrier is effectively regulated and controlled, the alumina carrier is in a double-peak pore shape, namely the pore diameter is concentrated in 10-30nm and 180-plus-500 nm, particularly the proportion of 180-plus-500 nm is obviously increased, the pore channels are communicated with each other, the mass transfer and diffusion of macromolecular reactants are facilitated, and the metal capacity is high, so that the catalyst has high activity, good stability and the operation period of the device can be prolonged.

(2) The rodlike alumina cluster body is pre-impregnated with the modifying element to modify the rodlike alumina, and the surface property of the rodlike alumina is effectively modulated by adding the modifying element, so that the hydrodemetallization catalytic activity and the hydrodesulfurization activity of the catalyst are improved.

(3) When the alumina carrier is subjected to sealing heat treatment in an ammonium bicarbonate aqueous solution, alumina carrier crystal grains grow secondarily in a closed, hydrothermal and alkaline atmosphere, rod-shaped alumina with the diameter of about 100-300nm and the surface of the alumina carrier grows about 1-12 mu m, and the rod-shaped alumina is crossed to form loose open pore channels, so that the phenomenon that metal elements are deposited on the outer surface of the catalyst to block the pore channels of the catalyst can be effectively prevented, the catalyst has excellent permeability, the activity of the catalyst can be ensured, and the catalyst has good stability.

Drawings

FIG. 1 shows a rod-like alumina cluster A₁Scanning electron micrograph (c).

FIG. 2 shows a rod-like alumina cluster A₂Scanning electron micrograph (c).

FIG. 3 is a scanning electron micrograph of the support II of example 1.

Detailed Description

The following examples are provided to further illustrate the technical solutions of the present invention, but the present invention is not limited to the following examples. In the present invention, wt% is a mass fraction.

Application N₂Physical adsorption-desorption characterization of the pore structures of the catalysts in the examples and the comparative examples, the specific operations are as follows: adopting ASAP-2420 type N₂And the physical adsorption-desorption instrument is used for characterizing the pore structure of the sample. A small amount of samples are taken to be treated for 3 to 4 hours in vacuum at the temperature of 300 ℃, and finally, the product is placed under the condition of liquid nitrogen low temperature (-200 ℃) to be subjected to nitrogen absorption-desorption test. Wherein the specific surface area is obtained according to a BET equation, and the distribution rate of the pore volume and the pore diameter below 50nm is obtained according to a BJH model.

Mercury pressing method: the mercury porosimeter is used for representing the pore diameter distribution of the catalysts in the examples and the comparative examples, and the specific operation is as follows: and characterizing the distribution of sample holes by using an American microphone AutoPore9500 full-automatic mercury porosimeter. The samples were dried, weighed into an dilatometer, degassed for 30 minutes while maintaining the vacuum conditions given by the instrument, and filled with mercury. The dilatometer was then placed in the autoclave and vented. Then proceed withAnd (5) boosting and reducing voltage. The mercury contact angle is 130 degrees, and the mercury interfacial tension is 0.485N.cm^-1The distribution ratio of pore diameter of 100nm or more is measured by mercury intrusion method.

A scanning electron microscope is used for representing the microstructure of the catalyst, and the specific operation is as follows: and a JSM-7500F scanning electron microscope is adopted to represent the microstructure of the carrier, the accelerating voltage is 5KV, the accelerating current is 20 muA, and the working distance is 8 mm. The alumina powder adopted in the embodiment and the comparative example is prepared by a method of aluminum sulfate and sodium metaaluminate.

Preparation of rod-like alumina cluster:

weighing 200 g of alumina powder, placing the alumina powder into 1200 g of ammonium bicarbonate aqueous solution with the mass concentration of 17.5wt%, sealing the alumina powder in a closed high-pressure kettle, carrying out heat treatment at 130 ℃ for 7 hours, filtering and washing the alumina powder, and drying the alumina powder at 110 ℃ for 6 hours to obtain a rod-shaped alumina cluster A₁，A₁The scanning electron micrograph of (a) is shown in FIG. 1.

Weighing 200 g of alumina powder, placing the alumina powder into 1600 g of ammonium bicarbonate aqueous solution with the mass concentration of 13.5wt%, sealing the alumina powder in a closed high-pressure kettle, carrying out heat treatment for 5 hours at 140 ℃, filtering and washing the alumina powder, and drying the alumina powder for 6 hours at 110 ℃ to prepare a rod-shaped alumina cluster A₂，A₂The scanning electron micrograph of (a) is shown in FIG. 2.