Zirconium-aluminum composite material preparation method and middle distillate hydrofining catalyst

Abstract

The invention discloses a preparation method of a zirconium-aluminum composite material and a middle distillate hydrofining catalyst, and the preparation method comprises the following steps: S1, adding zirconium oxychloride into water, stirring until the zirconium oxychloride is dissolved, then adjusting the pH value to 8.5-9.5, stirring, aging, washing with water, and carrying out suction filtration to obtain zirconium-containing hydrogel; s2, adding pseudo-boehmite, the zirconium-containing hydrogel and polyethylene glycol into water, uniformly stirring and mixing, heating, dropwise adding nitric acid, and performing constant-temperature acidolysis to form zirconium-aluminum sol; s3, adjusting the pH value of the zirconium-aluminum sol to 9-10 to form gel, aging, washing with water, and carrying out suction filtration to obtain a zirconium-aluminum composite material wet filter cake; and S4, adding diatomite, acetic acid and a lubricant into the wet filter cake, uniformly mixing, carrying out extrusion molding, carrying out vacuum freeze drying treatment, and roasting to obtain the zirconium-aluminum composite carrier. The method is simple in preparation process, and the obtained carrier is large in specific surface area and pore volume.

Description

Technical Field

[0001] The invention relates to the field of hydrorefining, and in particular to a method for preparing a zirconium-aluminum composite material and a catalyst for hydrorefining of middle distillate oil. Background Art

[0002] At present, the National VI diesel standard implemented in my country has put forward more stringent requirements for indicators such as sulfur content, cetane number, and polycyclic aromatic hydrocarbon content in diesel. The quality of automotive diesel is rapidly developing in the direction of low sulfur and low aromatics. At the same time, the degree of heavy and inferior quality of crude oil has intensified, the distillation range of diesel fractions has shifted backward, and the number of difficult-to-remove sulfides has increased, making desulfurization more difficult. How to achieve the cleanness of inferior raw materials and meet the market demand for high-quality clean diesel is one of the key tasks of refining and chemical companies. In the past two decades, the focus of diesel hydrorefining technology progress at home and abroad has been the development and use of hydrorefining catalysts with better performance to meet the production needs of clean diesel with increasingly stringent quality standards. As refining and chemical companies continue to promote cost reduction and efficiency improvement, the diesel hydrorefining units of various companies are faced with the production needs of processing inferior raw materials to produce high-quality products, reducing catalyst procurement costs, reducing unit operating costs, and extending the single-cycle operating time, which puts more stringent requirements on the activity, life, and cost of diesel hydrorefining catalysts. Therefore, reducing the catalyst stacking density and improving the catalyst activity and activity stability are still the development trends of diesel hydrorefining catalysts.

[0003] ZrO 2 As an important structural functional material, it has the characteristics of high temperature resistance, high hardness, good chemical stability and thermal stability, and is widely used in structural ceramics, sensors, solar cells, thermal insulation materials and other fields. Zirconium dioxide is easy to produce oxygen vacancies and can have unique interactions with active components, so it is also a very distinctive catalyst carrier. Catalysts based on zirconium oxide have shown unique advantages over conventional carriers, such as good sulfur resistance and easy reduction of supported metals. However, conventional zirconium dioxide carriers have small specific surface areas, underdeveloped pores, and irregular changes in pore size, which limit the performance of their excellent performance.

[0004] CN115254083A discloses a method for preparing an aluminum-zirconium composite carrier, which comprises the following steps: adding ammonia water to a zirconium-containing solution, adjusting the pH value, stirring, and aging to obtain a zirconium-containing hydrosol; filtering the zirconium-containing hydrosol to obtain a solid, washing with deionized water to remove Cl- in the solid, and obtaining a zirconium-containing hydrogel; adding pseudo-boehmite and methyl cellulose to the zirconium-containing hydrogel to obtain an aluminum-zirconium sol; adjusting the pH value of the aluminum-zirconium sol to form a gel, aging, washing, filtering, and drying to obtain an aluminum-zirconium composite material; grinding the composite material through a 180-mesh sieve, adding a binder and a lubricant to the composite material, mixing evenly, extruding and molding, and then drying and calcining to obtain ZrO 2 / γ-Al 2 O3 Composite carrier. The preparation process of this method is complicated. After the aluminum zirconium gel is washed and filtered, it needs to go through a drying process to obtain an aluminum zirconium composite material. The aluminum zirconium composite material needs to be ground, passed through a 180-mesh sieve, and then mixed evenly with a binder and a lubricant before extrusion molding. There are many factors affecting the preparation process, and the catalyst prepared by this method has a high bulk density.

[0005] CN202111681464.X discloses a ZrO 2 / γ-Al 2 O 3 A composite carrier and a preparation method thereof, a selective hydrodesulfurization catalyst and an application thereof. The composite carrier preparation method comprises: step 1, mixing zirconium oxychloride and water to obtain a zirconium-containing solution; step 2, adjusting the pH value of the zirconium-containing solution to alkaline, stirring, and aging; step 3, separating the aged material obtained in step 2 to obtain a solid, washing and removing Cl in the obtained solid - , obtaining a zirconium-containing hydrogel; step 4, mixing sucrose, pseudo-boehmite, the zirconium-containing hydrogel and water, heating, and acid hydrolyzing to obtain an aluminum zirconium sol; step 5, adjusting the pH value of the aluminum zirconium sol to alkaline, aging, then washing with water to neutrality, solid-liquid separation, vacuum freeze-drying, to obtain an aluminum zirconium composite material; step 6, grinding the composite material through a 180-mesh sieve, and then mixing with an auxiliary agent, forming, and obtaining ZrO 2 / γ-Al 2 O 3 Composite carrier. The catalyst of the invention has high DDS selectivity. The preparation process of this method is complicated. After the aluminum zirconium gel is washed and filtered, it needs to go through a drying process to obtain an aluminum zirconium composite material. The aluminum zirconium composite material needs to be ground, passed through a 180-mesh sieve, and then mixed evenly with a binder and a lubricant before extrusion molding. There are many factors affecting the preparation process. Summary of the invention

[0006] The object of the present invention is to provide a method for preparing a zirconium-aluminum composite material. The method has a simple preparation process and the obtained carrier has a large specific surface area and pore volume.

[0007] Another object of the present invention is to provide a catalyst for hydrotreating middle distillate oil.

[0008] To achieve the above object, the present invention provides a method for preparing a zirconium-aluminum composite material, comprising the following steps:

[0009] S1, adding zirconium oxychloride into water, stirring until dissolved, then adjusting the pH value to 8.5-9.5, stirring, aging, washing with water, and filtering to obtain a zirconium-containing hydrogel;

[0010] S2, adding pseudo-boehmite, zirconium-containing hydrogel and polyethylene glycol into water, stirring and mixing, heating and adding nitric acid dropwise, and acid-lyzing at a constant temperature to form a zirconium-aluminum sol;

[0011] S3, adjusting the pH of the zirconium-aluminum sol to 9-10, and after forming a gel, aging, washing, and filtering to obtain a wet filter cake of the zirconium-aluminum composite material;

[0012] S4, adding diatomaceous earth, acetic acid and lubricant to the wet filter cake, mixing evenly and then extruding to form, and obtaining the zirconium-aluminum composite carrier after vacuum freeze drying and calcination.

[0013] In the method for preparing the zirconium-aluminum composite material of the present invention, the mass ratio of the pseudo-boehmite to the zirconium oxychloride is 1 to 4:1.

[0014] In the method for preparing the zirconium-aluminum composite material of the present invention, the amount of polyethylene glycol added is 5-8% of the total mass of pseudo-boehmite and zirconium oxychloride.

[0015] In the method for preparing the zirconium-aluminum composite material of the present invention, the amount of diatomaceous earth added is 3-8% of the total mass of pseudo-boehmite and zirconium oxychloride.

[0016] In the method for preparing the zirconium-aluminum composite material of the present invention, the amount of acetic acid added is 2-5% of the total mass of pseudo-boehmite and zirconium oxychloride.

[0017] In the method for preparing the zirconium-aluminum composite material of the present invention, the lubricant is one or more of sesbania powder, dry starch and graphite.

[0018] In the method for preparing the zirconium-aluminum composite material of the present invention, the aging time in step S3 is 2 to 4 hours; the vacuum freeze-drying temperature in step S4 is -20 to -30°C, the pressure is 15 to 30 KPa, and the time is 8 to 24 hours; the calcination temperature is 420 to 600°C, and the calcination time is 2 to 5 hours.

[0019] In the method for preparing the zirconium-aluminum composite material of the present invention, in step S1, the mass ratio of zirconium oxychloride to water is 1:10-15, the stirring time is 2-4 hours, and the aging time is 8-10 hours.

[0020] In the method for preparing the zirconium-aluminum composite material of the present invention, the mass ratio of the amount of water added in step S2 to the total mass of pseudo-boehmite and zirconium oxychloride is 10-15:1, the heating temperature is 80-85°C, the acid-aluminum ratio is 0.1-0.2 mol / mol, and the constant temperature acidolysis time is 8-12h.

[0021] To achieve the above object, the present invention also provides a catalyst for hydrotreating middle distillate oil, comprising the composite material prepared by the above preparation method, and an active component WO 3 and NiO.

[0022] Beneficial effects of the present invention:

[0023] (1) Catalysts with excellent diffusion properties are conducive to the diffusion of complex sulfides and large molecular polycyclic aromatic hydrocarbons in the pores, improve the accessibility of the active center of the catalyst, and are conducive to the full play of the catalyst activity. The present invention uses polyethylene glycol to appropriately adjust the aggregation state of the microcrystalline particles of the catalytic material, and adopts a method of directly forming a wet filter cake of a zirconium-aluminum composite material, which simplifies the carrier preparation process, avoids the destruction of the internal accumulation state of the microcrystalline particle aggregates during the drying process of the wet filter cake of the catalytic material, improves the specific surface area and pore diffusion performance of the catalyst, and realizes a reduction in the catalyst stacking density, which can reduce the catalyst loading amount and reduce the catalyst procurement cost.

[0024] (2) For devices that process inferior raw materials and have harsh operating conditions, the catalyst is generally in a high-temperature operating state at the end of the device operation. The high temperature will further accelerate the aggregation of the active phase, causing the number of active centers to decrease, accelerating the deactivation of the catalyst, and is not conducive to the long-term stable operation of the catalyst. The present invention uses a sol-gel method to heat sinter ZrO 2 The catalyst carrier is introduced and combined with the vacuum freeze-drying method to prepare the catalyst. The stability of the active phase structure is improved by adjusting the surface properties of the carrier, and the active phase aggregation is reduced. At the same time, the catalyst has a larger pore and pore volume, which is conducive to improving the catalyst's ability to accommodate carbon deposits and metal impurity deposition, and also helps to extend the service life of the catalyst. The catalyst activity is guaranteed while the catalyst loading is reduced, the catalyst single cycle operation time is extended, and the device operation cost is reduced. DETAILED DESCRIPTION

[0025] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0026] Example 1

[0027] 40g ZrOCl 2 8H 2O was added into 400ml deionized water, stirred until dissolved, ammonia water was added dropwise to the solution, the pH value was adjusted to 8.5, stirred for 2h, aged for 8h, washed with water, and filtered to obtain a zirconium-containing hydrogel; the obtained zirconium-containing hydrogel, 121g pseudo-boehmite (dry basis 70wt%), and 8g polyethylene glycol were added into 1610g deionized water, stirred and mixed, and the mixture was heated to 80°C, and 16g nitric acid with a mass concentration of 65% was added dropwise while stirring, and acid hydrolyzed at constant temperature for 10h to form a zirconium aluminum sol; ammonia water was added to the above materials, the pH value was adjusted to 10, and after gel formation, it was aged for 3h and washed with water to neutrality, and filtered to obtain a wet cake; 5g diatomaceous earth, 4g sesbania powder, and 3.2g acetic acid were added to the wet cake, mixed evenly, and extruded; freeze-dried at 20KPa and -30°C for 8h, and calcined at 520°C for 3h to obtain a carrier; a supported tungsten-nickel catalyst was prepared by equal volume impregnation, wherein WO 3 The loading amounts of NiO and NiO are 28wt% and 5wt% respectively. Its main properties are listed in Table 1.

[0028] Example 2

[0029] 65g ZrOCl 2 8H 2 O was added into 780 ml of deionized water, stirred until dissolved, ammonia water was added dropwise to the solution, pH value was adjusted to 8.5, stirred for 3 h, aged for 10 h, washed with water, and filtered to obtain zirconium-containing hydrogel; the obtained zirconium-containing hydrogel, 107 g of pseudo-boehmite (dry basis 70 wt%), and 8.6 g of polyethylene glycol were added into 1720 g of deionized water, stirred and mixed, and the mixture was heated to 85°C, and 10. 7g, constant temperature acid hydrolysis for 8h to form zirconium aluminum sol; add ammonia water to the above materials, adjust the pH value to 9.5, after forming a gel, age for 4h, wash with water to neutrality, and filter to obtain a wet cake; add diatomaceous earth 9g, sesbania powder 4g, acetic acid 6.9g to the wet cake, mix well and extrude; freeze-dry at 15KPa and -20℃ for 12h, calcine at 500℃ for 4h to obtain a carrier; prepare a supported tungsten nickel catalyst by equal volume impregnation, wherein WO 3 The loading amounts of NiO and NiO are 28wt% and 5wt% respectively. Its main properties are listed in Table 1.

[0030] Example 3

[0031] 78g ZrOCl 2 8H 2O was added into 1170ml deionized water, stirred until dissolved, ammonia water was added dropwise to the solution, the pH value was adjusted to 9.5, stirred for 4h, aged for 8h, washed with water, and filtered to obtain a zirconium-containing hydrogel; the obtained zirconium-containing hydrogel, 100g of pseudo-boehmite (dry basis 70wt%), and 14.2g of polyethylene glycol were added into 2670g of deionized water, stirred and mixed, and the mixture was heated to 85°C, and 6.7g of nitric acid with a mass concentration of 65% was added dropwise while stirring, and constant temperature acid hydrolysis was performed for 12h to form a zirconium aluminum sol; ammonia water was added to the above materials, the pH value was adjusted to 9, and after gel formation, it was aged for 2h and washed with water to neutrality, and filtered to obtain a wet cake; 14g of diatomaceous earth, 4g of sesbania powder, and 9g of acetic acid were added to the wet cake, mixed evenly, and extruded; freeze-dried at 30KPa and -25°C for 24h, and calcined at 600°C for 2h to obtain a carrier; a supported tungsten-nickel catalyst was prepared by equal volume impregnation, wherein WO 3 The loading amounts of NiO and NiO are 28wt% and 5wt% respectively. Its main properties are listed in Table 1.

[0032] Example 4

[0033] 52g ZrOCl 2 8H 2 O was added into 624 ml of deionized water, stirred until dissolved, ammonia water was added dropwise to the solution, the pH value was adjusted to 9, stirred for 2 hours, aged for 9 hours, washed with water, and filtered to obtain a zirconium-containing hydrogel; the obtained zirconium-containing hydrogel, 114 g of pseudo-boehmite (dry basis 70 wt%), and 10 g of polyethylene glycol were added into 1992 g of deionized water, stirred and mixed, and the mixture was heated to 80°C, and 11.4 g of nitric acid with a mass concentration of 65% was added dropwise while stirring, and constant temperature acid hydrolysis was performed for 11 hours to form a zirconium aluminum sol; ammonia water was added to the above materials, the pH value was adjusted to 9.5, and after gel formation, it was aged for 2 hours and washed with water until neutral, and filtered to obtain a wet cake; 10 g of diatomaceous earth, 4 g of sesbania powder, and 5 g of acetic acid were added to the wet cake, mixed evenly, and extruded; freeze-dried at 15 KPa and -30°C for 18 hours, and calcined at 450°C for 5 hours to obtain a carrier; a supported tungsten-nickel catalyst was prepared by equal volume impregnation, wherein WO 3 The loading amounts of NiO and NiO are 28wt% and 5wt% respectively. Its main properties are listed in Table 1.

[0034] Comparative Example 1

[0035] According to the example in patent CN115254083A, 71 g of zirconium oxychloride was added to a container containing 1000 ml of deionized water, stirred until fully dissolved, and diluted ammonia water was slowly added dropwise to adjust the pH value to 10, stirred for 2 h, aged for 5 h, filtered, and the Cl in the obtained solid was washed with deionized water. -, and obtain a zirconium-containing hydrogel. 6.8g of methyl cellulose, 203g of pseudo-boehmite (dry basis 70wt%) and the obtained zirconium-containing hydrogel are added to 4932g of deionized water, stirred and mixed, and then the mixture is heated to 85°C, and nitric acid with a mass concentration of 65% is slowly added while stirring to adjust the pH of the system to 3, and acid hydrolyze at constant temperature for 6h; then an appropriate amount of ammonia water is slowly added to adjust the pH of the aluminum zirconium sol to 9.5 to form a gel, aged for 8h, washed with deionized water to a pH of 7, filtered and dried to obtain an aluminum zirconium composite material, the composite material is ground, passed through a 180-mesh sieve, 2wt% sesbania powder and 3wt% nitric acid are added, mixed evenly, and extruded, and then dried at 110°C for 2h and calcined at 500°C for 4h to obtain ZrO 2 / γ-Al 2 O 3 Composite carrier. After the carrier preparation is completed, the tungsten-nickel catalyst is loaded by equal volume impregnation method, in which WO 3 The loading amounts of NiO and MgO are 28 wt% and 5 wt% respectively, and Comparative Example 1 is obtained.

[0036] Comparative Example 2

[0037] 40g ZrOCl 2 8H 2 O was added into 400 ml of deionized water and stirred until dissolved. Ammonia water was added to the solution, the pH value was adjusted to 8.5, stirred for 2 hours, aged for 8 hours, washed with water, and filtered to obtain a zirconium-containing hydrogel; the obtained zirconium-containing hydrogel and 121 g of pseudo-boehmite were added into deionized water with a solid-liquid mass ratio of 1:10, stirred and mixed, and the mixture was heated to 80°C, and 16 g of nitric acid with a mass concentration of 65% was added while stirring, and acid hydrolyzed at constant temperature for 10 hours to form a zirconium aluminum sol; ammonia water was added to the above materials, the pH value was adjusted to 10, and after gel formation, it was washed with water after aging for 3 hours to neutrality, and filtered to obtain a wet cake; 5 g of diatomaceous earth, 4 g of sesbania powder, and 3.2 g of acetic acid were added to the wet cake, mixed evenly, and extruded; freeze-dried at 20 KPa and -30°C for 8 hours, and calcined at 520°C for 3 hours to obtain a carrier; a supported tungsten-nickel catalyst was prepared by equal volume impregnation, wherein WO 3 The loading amounts of NiO and NiO are 28wt% and 5wt% respectively. Its main properties are listed in Table 1.

[0038] Test Example 1

[0039] The above catalyst was evaluated for its hydrorefining performance in a 200 ml fixed bed reactor. The properties of the raw materials are shown in Table 2. The test conditions were: hydrogen partial pressure 9 MPa, reaction temperature 365 °C, space velocity 1.5 h -1 , hydrogen-to-oil ratio 400:1, and the catalyst activity evaluation data are shown in Table 3.

[0040] Table 1 shows the structural characteristics and strength property data of the catalysts obtained in Examples 1 to 4 and Comparative Example 1.

[0041] Table 1 Catalyst properties

[0042]

[0043] Table 2 Raw oil properties

[0044] project Diesel Fuel <![CDATA[Density (20 °C), kg / m 3 > 874 Nitrogen content, ppm 353 Sulfur content, ppm 9460 PAHs, wt% 20.9

[0045] Table 3 Catalyst hydrogenation evaluation results

[0046]

[0047] It can be seen from Table 3 that the hydrodesulfurization activity and aromatic saturation performance of the catalysts provided by Examples 1 to 4 of the present invention are higher than those of the catalyst of Comparative Example 1. And the bulk density of the catalysts provided by Examples 1 to 4 is lower than that of the catalyst of Comparative Example 1.

[0048] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a zirconium-aluminum composite material, It is characterized in that The following steps are involved: S1, adding zirconium oxychloride into water, stirring until dissolved, then adjusting the pH value to 8.5-9.5, stirring, aging, washing with water, and filtering to obtain a zirconium-containing hydrogel; S2, adding pseudo-boehmite, zirconium-containing hydrogel and polyethylene glycol into water, stirring and mixing, heating and adding nitric acid dropwise, and acid-lyzing at a constant temperature to form a zirconium-aluminum sol; S3, adjusting the pH of the zirconium-aluminum sol to 9-10, and after forming a gel, aging, washing, and filtering to obtain a wet filter cake of the zirconium-aluminum composite material; S4, adding diatomaceous earth, acetic acid and lubricant to the wet filter cake, mixing evenly and then extruding to form, and obtaining the zirconium-aluminum composite carrier after vacuum freeze drying and calcination.

2. The method for preparing the zirconium-aluminum composite material according to claim 1, It is characterized in that The mass ratio of the pseudo-boehmite to the zirconium oxychloride is 1 to 4:

1.

3. The method for preparing the zirconium-aluminum composite material according to claim 1, It is characterized in that The amount of polyethylene glycol added is 5-8% of the total mass of pseudo-boehmite and zirconium oxychloride.

4. The method for preparing the zirconium-aluminum composite material according to claim 1, It is characterized in that The amount of diatomaceous earth added is 3-8% of the total mass of pseudo-boehmite and zirconium oxychloride.

5. The method for preparing the zirconium-aluminum composite material according to claim 1, It is characterized in that The amount of acetic acid added is 2-5% of the total mass of pseudo-boehmite and zirconium oxychloride.

6. The method for preparing the zirconium-aluminum composite material according to claim 1, It is characterized in that The lubricant is one or more of sesbania powder, dry starch and graphite.

7. The method for preparing the zirconium-aluminum composite material according to claim 1, It is characterized in that The aging time in step S3 is 2 to 4 hours; the vacuum freeze-drying temperature in step S4 is -20 to -30°C, the pressure is 15 to 30 KPa, and the time is 8 to 24 hours; the roasting temperature is 420 to 600°C, and the roasting time is 2 to 5 hours.

8. The method for preparing the zirconium-aluminum composite material according to claim 1, It is characterized in that In step S1, the mass ratio of zirconium oxychloride to water is 1:10-15, the stirring time is 2-4 hours, and the aging time is 8-10 hours.

9. The method for preparing the zirconium-aluminum composite material according to claim 1, It is characterized in that In step S2, the mass ratio of the amount of water added to the total mass of pseudo-boehmite and zirconium oxychloride is 10-15:1, the heating temperature is 80-85° C., the acid-aluminum ratio is 0.1-0.2 mol / mol, and the constant temperature acidolysis time is 8-12 h.

10. A catalyst for hydrotreating middle distillate oil, It is characterized in that A composite material comprising the composite material prepared by the preparation method according to any one of claims 1 to 9, and an active component WO 3 and NiO.

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