Method for preparing zirconium-aluminum composite material and middle distillate hydrofining catalyst

Abstract

The application discloses a zirconium-aluminum composite material preparation method and a middle distillate oil hydrofining catalyst, and the preparation method comprises the following steps: 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 suction filtering to obtain a zirconium-containing water gel; S2, adding pseudo-boehmite, the zirconium-containing water gel and polyethylene glycol into water, stirring and uniformly mixing, then heating and adding nitric acid drop by drop, constant-temperature acidolysis, and forming a zirconium-aluminum sol; S3, adjusting the pH value of the zirconium-aluminum sol to 9-10, after forming a gel, aging, washing with water, and suction filtering, a zirconium-aluminum composite material wet filter cake is obtained; and S4, uniformly mixing diatomite, acetic acid and a lubricant in the wet filter cake, then extruding into a shape, and after vacuum freeze-drying treatment and calcination, a zirconium-aluminum composite carrier is obtained. The method has a simple preparation process, and the obtained carrier has a large specific surface area and pore volume.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of hydrofining, in particular to a preparation method of zirconium-aluminum composite material and a hydrofining catalyst for middle distillate oil. BACKGROUND

[0002] The current national VI diesel standard implemented in China puts forward more stringent requirements on sulfur content, cetane number and polycyclic aromatic hydrocarbon content in diesel. The quality of diesel for vehicles is rapidly developing towards low sulfur and low aromatic hydrocarbons. At the same time, the degree of heavy and poor quality of crude oil is increasing, the distillation range of diesel fraction is moving backward, and the removal of sulfides is increasing, making it more difficult to remove sulfur. How to realize the cleanization of poor quality raw materials and meet the consumer demand for high-quality clean diesel is one of the key tasks of refining enterprises. In the past two decades, the focus of the development of diesel hydrofining technology at home and abroad is to develop and use hydrofining catalysts with better performance to meet the needs of producing clean diesel with increasingly stringent quality standards. With the continuous promotion of cost reduction and efficiency improvement by refining enterprises, diesel hydrofining units in various enterprises are faced with the need to produce high-quality products from poor-quality raw materials, reduce catalyst procurement costs, reduce device operating costs and extend the single-cycle operation time, which puts forward more stringent requirements on the activity, life and cost of diesel hydrofining catalysts. Therefore, reducing the bulk density of the catalyst, improving the activity and stability of the catalyst are still the trend of development of diesel hydrofining catalysts.

[0003] ZrO2 is an important structural and functional material, which has the characteristics of high temperature resistance, high hardness, good chemical and thermal stability, and is widely used in structural ceramics, sensors, solar cells, thermal insulation materials and other fields. Zirconia is easy to produce oxygen vacancies, which can interact with active components, so it is also a unique catalyst carrier. Compared with conventional carriers, zirconia-based catalysts have unique advantages such as good sulfur resistance and easy reduction of supported metals. However, the conventional zirconia carrier has small specific surface area, underdeveloped pores, and irregular pore size, which limits the performance of the catalyst.

[0004] CN115254083A discloses a preparation method of an aluminum-zirconium composite carrier, which comprises the following steps: adding ammonia water in a zirconium-containing solution, adjusting the pH value, stirring, and obtaining a zirconium-containing hydrosol after aging; the zirconium-containing hydrosol is suction filtered to obtain a solid, and the solid is washed with deionized water to remove Cl- in the solid, thereby obtaining a zirconium-containing hydrogel; pseudo-boehmite and methyl cellulose are added to the zirconium-containing hydrogel to prepare an aluminum-zirconium sol; the pH value of the aluminum-zirconium sol is adjusted to form a gel, which is aged, washed with water, suction filtered, and dried to obtain an aluminum-zirconium composite material; the composite material is ground through a 180-mesh sieve, and then binders and lubricants are added and uniformly mixed, and then extruded into a shape, and then dried and calcined to obtain a ZrO2 / γ-Al2O3 composite carrier. The preparation process of the method is complex, the aluminum-zirconium gel needs to be dried after water washing and suction filtering to obtain the aluminum-zirconium composite material, the aluminum-zirconium composite material needs to be ground and passed through a 180-mesh sieve, and then mixed with binders and lubricants and extruded into a shape, and there are many influencing factors in the preparation process, and the catalyst prepared by the method has a high bulk density.

[0005] CN202111681464.X discloses a ZrO2 / γ-Al2O3 composite carrier, a preparation method thereof, a selective hydrodesulfurization catalyst and an application thereof. The preparation method of the composite carrier comprises the following steps: 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 be alkaline, stirring and aging; step 3, separating the solid from the aged material obtained in step 2, washing to remove Cl - from the obtained solid, and obtaining a zirconium-containing hydrogel; step 4, mixing sucrose, pseudo-boehmite, the zirconium-containing hydrogel and water, heating, and acidolysis to obtain an aluminum-zirconium sol; step 5, adjusting the pH value of the aluminum-zirconium sol to be alkaline, aging, then washing with water to be neutral, solid-liquid separation, vacuum freeze-drying to obtain an aluminum-zirconium composite material; and step 6, grinding the composite material through a 180-mesh sieve, mixing with an additive, and shaping to obtain a ZrO2 / γ-Al2O3 composite carrier. The catalyst has high DDS selectivity. The preparation process is complex, the aluminum-zirconium gel needs to be dried after water washing and suction filtering to obtain the aluminum-zirconium composite material, the aluminum-zirconium composite material needs to be ground and passed through a 180-mesh sieve, and then mixed with binders and lubricants and extruded into a shape, and there are many influencing factors in the preparation process. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of a zirconium-aluminum composite material, which has a simple preparation process and a large specific surface area and pore volume of the obtained carrier.

[0007] The purpose of the present application is also to provide a middle distillate oil hydrofining catalyst.

[0008] To achieve the above-mentioned purposes, the present application provides a preparation method of a zirconium-aluminum composite material, which comprises the following steps:

[0009] S1, zirconium oxychloride is added to water, stirred until dissolved, then the pH value is adjusted to 8.5-9.5, stirred, aged, washed with water, and filtered to obtain a zirconium-containing hydrogel;

[0010] S2, pseudo-boehmite, zirconium-containing hydrogel, and polyethylene glycol are added to water, stirred and mixed uniformly, then heated and added dropwise with nitric acid, and constant-temperature acidolysis is performed to form a zirconium-aluminum sol;

[0011] S3, the pH of the zirconium-aluminum sol is adjusted to 9-10, and after the gel is formed, aging, water washing, and filtration are performed to obtain a zirconium-aluminum composite material wet filter cake;

[0012] S4, diatomite, acetic acid, and a lubricant are added to the wet filter cake, mixed uniformly, and then extruded into a shape, and after vacuum freeze-drying treatment and calcination, a zirconium-aluminum composite carrier is obtained.

[0013] The mass ratio of the pseudo-boehmite and the zirconium oxychloride in the preparation method of the zirconium-aluminum composite material is 1-4:1.

[0014] The polyethylene glycol is added in an amount of 5-8% of the total mass of the pseudo-boehmite and the zirconium oxychloride in the preparation method of the zirconium-aluminum composite material.

[0015] The diatomite is added in an amount of 3-8% of the total mass of the pseudo-boehmite and the zirconium oxychloride in the preparation method of the zirconium-aluminum composite material.

[0016] The acetic acid is added in an amount of 2-5% of the total mass of the pseudo-boehmite and the zirconium oxychloride in the preparation method of the zirconium-aluminum composite material.

[0017] The lubricant is one or more of amaranth powder, dry starch, and graphite in the preparation method of the zirconium-aluminum composite material.

[0018] In the preparation method of the zirconium-aluminum composite material, the aging time in step S3 is 2-4h; the temperature of the vacuum freeze-drying in step S4 is -20--30℃, the pressure is 15-30KPa, and the time is 8-24h; and the calcination temperature is 420-600℃, and the calcination time is 2-5h.

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

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

[0021] To achieve the above object, the present application further provides a middle distillate hydrofining catalyst, which comprises the composite prepared by the preparation method and active components WO3 and NiO.

[0022] The present application has the following advantages:

[0023] (1) The catalyst with excellent diffusion performance is beneficial to the diffusion of complex structure sulfides and macromolecular polycyclic aromatic hydrocarbons in the pore, improves the accessibility of the active center of the catalyst, and is beneficial to the full play of the activity of the catalyst. The present application uses polyethylene glycol to appropriately adjust the aggregation state of the microcrystalline particles of the catalytic material, uses the method of directly forming the zirconium-aluminum composite wet filter cake, simplifies the preparation process of the carrier, avoids the damage to the internal accumulation state of the microcrystalline particle aggregates in 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 at the same time, realizes the reduction of the bulk density of the catalyst, which can reduce the loading amount of the catalyst and reduce the procurement cost of the catalyst.

[0024] (2) For processing poor quality raw materials, the device is running in harsh conditions, and the catalyst is generally in a high temperature running state at the end of the device operation. At high temperature, the aggregation of the active phase will be further accelerated, causing the number of active centers to decrease, accelerating the deactivation of the catalyst, which is not conducive to the long-period stable operation of the catalyst. The present application introduces ZrO2 with excellent thermal sintering stability into the catalyst carrier by sol-gel method and prepares the catalyst by vacuum freeze drying method, improves the stability of the active phase structure by adjusting the surface properties of the carrier, and reduces the aggregation of the active phase. At the same time, the catalyst has large pore and pore volume, which is beneficial to improve the ability of the catalyst to accommodate carbon deposition and metal impurities deposition, and is also helpful to prolong the service life of the catalyst. It solves the problem of ensuring the activity of the catalyst while reducing the loading amount of the catalyst, prolongs the single-period operation time of the catalyst, and reduces the operation cost of the device. DETAILED DESCRIPTION

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

[0026] Example 1

[0027] ZrOCl2*8H2O 40 g was added to 400 ml of deionized water and stirred until dissolved. Ammonia was added dropwise to the solution to adjust the pH to 8.5. The solution was stirred for 2 h and aged for 8 h. The solution was washed with water and filtered to obtain a zirconium-containing hydrogel. The zirconium-containing hydrogel was mixed with pseudoboehmite (dry basis 70 wt%) 121 g and polyethylene glycol 8 g in 1610 g of deionized water. The mixture was stirred and heated to 80°C. Concentrated nitric acid (65 wt%) 16 g was added dropwise while stirring. The mixture was acidified for 10 h at constant temperature to form a zirconium-aluminum sol. Ammonia was added to the mixture to adjust the pH to 10. The mixture was aged for 3 h and washed with water until neutral. The wet filter cake was obtained by filtration. The wet filter cake was mixed with diatomite 5 g and sesbania powder 4 g. Acetic acid 3.2 g was added to the mixture. The mixture was extruded and formed into a shape. The extruded and formed mixture was freeze-dried at 20 KPa and -30°C for 8 h. The dried mixture was calcined at 520°C for 3 h to obtain a support. An equal volume impregnation method was used to prepare a supported tungsten-nickel catalyst. The loadings of WO3 and NiO were 28 wt% and 5 wt%, respectively. The main properties of the catalyst are listed in Table 1.

[0028] Example 2

[0029] ZrOCl2*8H2O 65 g was added to 780 ml of deionized water and stirred until dissolved. Ammonia was added dropwise to the solution to adjust the pH to 8.5. The solution was stirred for 3 h and aged for 10 h. The solution was washed with water and filtered to obtain a zirconium-containing hydrogel. The zirconium-containing hydrogel was mixed with pseudoboehmite (dry basis 70 wt%) 107 g and polyethylene glycol 8.6 g in 1720 g of deionized water. The mixture was stirred and heated to 85°C. Concentrated nitric acid (65 wt%) 10.7 g was added dropwise while stirring. The mixture was acidified for 8 h at constant temperature to form a zirconium-aluminum sol. Ammonia was added to the mixture to adjust the pH to 9.5. The mixture was aged for 4 h and washed with water until neutral. The wet filter cake was obtained by filtration. The wet filter cake was mixed with diatomite 9 g and sesbania powder 4 g. Acetic acid 6.9 g was added to the mixture. The mixture was extruded and formed into a shape. The extruded and formed mixture was freeze-dried at 15 KPa and -20°C for 12 h. The dried mixture was calcined at 500°C for 4 h to obtain a support. An equal volume impregnation method was used to prepare a supported tungsten-nickel catalyst. The loadings of WO3 and NiO were 28 wt% and 5 wt%, respectively. The main properties of the catalyst are listed in Table 1.

[0030] Example 3

[0031] Zirconium hydrogel was prepared by adding 78 g of ZrOCl2*8H2O into 1170 ml of deionized water, stirring until dissolved, adding ammonia water to the solution to adjust the pH value to 9.5, stirring for 4 h, aging for 8 h, washing with water, and then filtering to obtain the zirconium-containing hydrogel. The zirconium-containing hydrogel was mixed with pseudo-boehmite (dry basis 70 wt%) 100 g and polyethylene glycol 14.2 g in 2670 g of deionized water, and then the mixture was heated to 85°C and stirred while adding 6.7 g of 65% nitric acid dropwise. The mixture was acidified at constant temperature for 12 h to form a zirconium-aluminum sol. Ammonia water was added to the above mixture to adjust the pH value to 9. After the gel was formed, it was aged for 2 h, washed with water to neutral, and then filtered to obtain a wet filter cake. Diatomite 14 g and sesbania powder 4 g were added to the wet filter cake, and then acetic acid 9 g was added to mix uniformly. The mixture was extruded into a shape. The extruded mixture was freeze-dried at 30 KPa and -25°C for 24 h, and then calcined at 600°C for 2 h to obtain a carrier. A supported tungsten-nickel catalyst was prepared by equal-volume impregnation, and the loadings of WO3 and NiO were 28 wt% and 5 wt%, respectively. The main properties of the catalyst are listed in Table 1.

[0032] Example 4

[0033] Zirconium hydrogel was prepared by adding 52 g of ZrOCl2*8H2O into 624 ml of deionized water, stirring until dissolved, adding ammonia water to the solution to adjust the pH value to 9, stirring for 2 h, aging for 9 h, washing with water, and then filtering to obtain the zirconium-containing hydrogel. The zirconium-containing hydrogel was mixed with pseudo-boehmite (dry basis 70 wt%) 114 g and polyethylene glycol 10 g in 1992 g of deionized water, and then the mixture was heated to 80°C and stirred while adding 11.4 g of 65% nitric acid dropwise. The mixture was acidified at constant temperature for 11 h to form a zirconium-aluminum sol. Ammonia water was added to the above mixture to adjust the pH value to 9.5. After the gel was formed, it was aged for 2 h, washed with water to neutral, and then filtered to obtain a wet filter cake. Diatomite 10 g and sesbania powder 4 g were added to the wet filter cake, and then acetic acid 5 g was added to mix uniformly. The mixture was extruded into a shape. The extruded mixture was freeze-dried at 15 KPa and -30°C for 18 h, and then calcined at 450°C for 5 h to obtain a carrier. A supported tungsten-nickel catalyst was prepared by equal-volume impregnation, and the loadings of WO3 and NiO were 28 wt% and 5 wt%, respectively. The main properties of the catalyst are listed in Table 1.

[0034] Comparative Example 1

[0035] According to the method described in Example of patent CN115254083A, zirconium oxychloride 71 g was added into a container containing 1000 ml of deionized water, stirred until dissolved, and then diluted ammonia water was slowly added dropwise. The pH value was adjusted to 10, the mixture was stirred for 2 h, and then aged for 5 h. The obtained solid was washed with deionized water to remove Cl -ZrOCl2-8H2O 40 g was added to 400 ml of deionized water and stirred until dissolved. Ammonia water was added dropwise to the solution to adjust the pH to 8.5. After stirring for 2 h and aging for 8 h, the solution was washed with water and filtered to obtain a zirconium-containing hydrogel. The zirconium-containing hydrogel and pseudo-boehmite 121 g were added to deionized water at a solid-to-liquid mass ratio of 1:10. After stirring and mixing, the mixture was heated to 80°C. While stirring, 65% nitric acid 16 g was added dropwise. The mixture was acid hydrolyzed at constant temperature for 10 h to form a zirconium-aluminum sol. Ammonia water was added to the above mixture to adjust the pH to 10. After the gel was formed, it was aged for 3 h and then washed with water until neutral. The wet filter cake was obtained by filtration. Diatomite 5 g, sesbania powder 4 g, and acetic acid 3.2 g were added to the wet filter cake and mixed uniformly. The mixture was extruded and molded. The molded product was freeze-dried at 20 kPa and -30°C for 8 h and then calcined at 520°C for 3 h to obtain a carrier. A supported tungsten-nickel catalyst was prepared by the equal-volume impregnation method. The loadings of WO3 and NiO were 28 wt% and 5 wt%, respectively. The main properties of the catalyst are listed in Table 1.

[0036] Comparative Example 2

[0037] ZrOCl2-8H2O 40 g was added to 400 ml of deionized water and stirred until dissolved. Ammonia water was added dropwise to the solution to adjust the pH to 8.5. After stirring for 2 h and aging for 8 h, the solution was washed with water and filtered to obtain a zirconium-containing hydrogel. The zirconium-containing hydrogel and pseudo-boehmite 121 g were added to deionized water at a solid-to-liquid mass ratio of 1:10. After stirring and mixing, the mixture was heated to 80°C. While stirring, 65% nitric acid 16 g was added dropwise. The mixture was acid hydrolyzed at constant temperature for 10 h to form a zirconium-aluminum sol. Ammonia water was added to the above mixture to adjust the pH to 10. After the gel was formed, it was aged for 3 h and then washed with water until neutral. The wet filter cake was obtained by filtration. Diatomite 5 g, sesbania powder 4 g, and acetic acid 3.2 g were added to the wet filter cake and mixed uniformly. The mixture was extruded and molded. The molded product was freeze-dried at 20 kPa and -30°C for 8 h and then calcined at 520°C for 3 h to obtain a carrier. A supported tungsten-nickel catalyst was prepared by the equal-volume impregnation method. The loadings of WO3 and NiO were 28 wt% and 5 wt%, respectively. The main properties of the catalyst are listed in Table 1.

[0038] Test Example 1

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

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

[0041] Table 1 Catalyst properties

[0042] ​

[0043] Table 2 Properties of raw oil

[0044] Item Mixed diesel Density (20°C), kg / m 3 ]] 874 Nitrogen content, ppm 353 Sulfur content, ppm 9460 Polycyclic aromatic hydrocarbons, wt% 20.9

[0045] Table 3 Catalyst hydrogenation evaluation results

[0046]

[0047] As can be seen from Table 3, the hydrogenation desulfurization activity and aromatic saturation performance of the catalysts provided by Examples 1-4 are higher than that of the catalyst of Comparative Example 1. The bulk densities of the catalysts provided by Examples 1-4 are lower than that of the catalyst of Comparative Example 1.

[0048] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications shall all belong to the protection scope of the claims of the present application.

Claims

1. A method for producing a zirconium-aluminum composite material, characterized by, It consists of the following steps: S1, zirconium oxychloride is added into water, stirred until dissolved, then the pH value is adjusted to 8.5~9.5, stirred, aged, washed with water, and filtered to obtain a zirconium-containing hydrogel; S2, pseudo-boehmite, zirconium-containing hydrogel and polyethylene glycol are added into water, stirred and mixed uniformly, then heated and added dropwise with nitric acid, and constant temperature acidolysis is performed to form a zirconium-aluminum sol; S3, the pH value of the zirconium-aluminum sol is adjusted to 9~10, and after the gel is formed, aging, washing with water, and filtering are performed to obtain a zirconium-aluminum composite material wet filter cake; S4, diatomite, acetic acid and a lubricant are added into the wet filter cake, mixed uniformly, and then extruded into a shape, and after vacuum freeze drying treatment and calcination, a zirconium-aluminum composite material is obtained; the temperature of the vacuum freeze drying is -30~-20℃, and the pressure is 15~30KPa; The mass ratio of the pseudo-boehmite and the zirconium oxychloride is (1~4):1; The polyethylene glycol is added in an amount of 5~8% of the total mass of the pseudo-boehmite and the zirconium oxychloride.

2. The method of claim 1, wherein the zirconium-aluminum composite material is prepared by a method comprising: The diatomite is added in an amount of 3~8% of the total mass of the pseudo-boehmite and the zirconium oxychloride. ​ 3. The method of claim 1, wherein the zirconium-aluminum composite material is prepared by a process comprising: The acetic acid is added in an amount of 2~5% of the total mass of the pseudo-boehmite and the zirconium oxychloride. ​ 4. The method for preparing zirconium-aluminum composite material according to claim 1, characterized in that, The lubricant is one or more of sesbania powder, dry starch and graphite.

5. The method of claim 1, wherein the zirconium-aluminum composite material is prepared by a process comprising: The aging time in step S3 is 2~4h; the vacuum freeze drying time in step S4 is 8~24h; and the calcination temperature is 420~600℃, and the calcination time is 2~5h. ​ 6. The method of claim 1, wherein the zirconium-aluminum composite material is prepared by a process comprising: In step S1, the mass ratio of the zirconium oxychloride to water is 1:(10~15), the stirring time is 2~4h, and the aging time is 8~10h.

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

8. A middle distillate hydrofmishing catalyst characterized by, The zirconium-aluminum composite material carrier prepared by the preparation method of any one of claims 1~7, and the active components WO3 and NiO.

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