Amorphous silica-alumina-based support, white oil hydrogenation catalyst and method for preparing and use thereof

Abstract

The present application provides an amorphous silicon-aluminum-based carrier, a white oil hydrogenation catalyst and a preparation method and application thereof, the preparation method of the amorphous silicon-aluminum-based carrier comprises the following steps: S1: an amorphous silicon-aluminum material is prepared by using a silicon source and an aluminum source; S2: the amorphous silicon-aluminum material is modified by using boric acid and urea in sequence to obtain the amorphous silicon-aluminum-based carrier. The white oil hydrogenation catalyst prepared by the present application has the characteristics of high specific surface area, large pore volume and large pore size, and has a beneficial pore structure; in addition, the white oil hydrogenation catalyst has more acid active sites, more total weak acid amount, more B acid content and stronger B acid acidity.

Description

Technical Field

[0001] This invention relates to the field of hydrogenation catalyst technology, specifically to an amorphous silica-alumina-based support, a white oil hydrogenation catalyst, its preparation method, and its application. Background Technology

[0002] Currently, the consumer market is experiencing a growing demand for cosmetic-grade, food-grade, and pharmaceutical-grade white oils, as well as white oils used in polystyrene resin, plastics, and rubber processing. Polystyrene (PS) requires a white mineral oil during its production; this oil is commonly referred to as plastic oil. The purpose of adding this white oil is to improve flowability during injection molding, provide internal lubrication, and increase the product's plasticity, toughness, and elasticity. Depending on the type of PS, the amount of white oil added ranges from 1-6 wt%.

[0003] White oil feedstocks contain both monocyclic and polycyclic aromatic hydrocarbons (PAHs). Monocyclic PAHs often have numerous long branches, making them difficult for catalysts to adsorb and hydrogenate to saturation. White oil hydrogenation catalysts, requiring deep hydrogenation of the oil, must possess a wide, open pore structure with large pore volume and diameter. The catalyst support for white oil hydrogenation is generally amorphous silica-alumina. Due to its tunable pore structure and suitable acidity, amorphous silica-alumina exhibits high yields for aromatic saturation reactions and essentially does not alter the viscosity, viscosity index, or other properties of the base oil feedstock, making it widely used by researchers. White oil hydrogenation catalysts also need strong hydrogenation saturation capabilities. Their active metals are typically Group VIII metals such as Co, Ni, Pt, or Pd, resulting in Ni-based catalysts and noble metal catalysts, with noble metal catalysts generally exhibiting better performance.

[0004] Polystyrene white oil (PS white oil) is a type of high-grade white oil, requiring characteristics such as extremely low aromatic hydrocarbon content, good light and heat stability, and a Seybert color greater than +30. On one hand, PS white oil must have good compatibility with polystyrene. Therefore, the raw materials for producing PS white oil should ideally have a high content of cycloalkanes and a low content of alkanes. On the other hand, it must have excellent resistance to yellowing, meaning PS white oil must possess excellent light and heat stability. Furthermore, PS white oil should also be odorless, tasteless, have a high open flash point, and good low-temperature fluidity. These high quality requirements for PS white oil pose significant challenges to both raw material sourcing and processing technology.

[0005] The quality requirements for PS white oil include a cycloalkane carbon form distribution (Cn) > 32, a 5% distillation point carbon number > 22, and a high open-cup flash point. These requirements can be met by selecting suitable naphthenic heavy distillate oils or by blending paraffinic and naphthenic oils in appropriate proportions. The extremely low aromatic content in PS white oil necessitates a high-performance catalyst for its hydrogenation. Therefore, developing a refining catalyst suitable for aromatic saturation in naphthenic heavy distillate oils is a method to improve white oil quality.

[0006] In the prior art, CN106479565B discloses a method for producing polystyrene white oil. The steps include solvent refining of a fraction of naphthenic crude oil to obtain refined oil, followed by hydrogenation and fractionation to obtain polystyrene white oil. The hydrogenation process includes hydrotreating, catalytic dewaxing, hydrorefining, and deep hydrogenation saturation of aromatics. The deep hydrogenation saturation catalysts used are Shell's supplemental refining catalyst LN-5 and the industrially produced white oil hydrogenation catalyst RLF-10 from the Research Institute of Petroleum Processing (RIPP). The process conditions are a hydrogen partial pressure of 12.0-17.0 MPa, a reaction temperature of 200-260℃, and a volume hourly space velocity (VHSV) of 0.4-1.0 h⁻¹. -1 The product is fractionated, with the fraction above 340℃ used as polyolefin white oil. This process involves four stages of hydrogenation: hydrorefining / catalytic dewaxing, supplementary refining, and deep aromatic saturation of the naphthenic feedstock. It has disadvantages such as a long process flow, large product yield loss, and high cost of supporting equipment.

[0007] CN114479934A discloses a polystyrene-specific white oil and its preparation method. The preparation method includes: dewaxing paraffinic distillate oil using a ketone-benzene dewaxing device to obtain dewaxed refined oil; subjecting the dewaxed refined oil to hydrotreating, hydroisomerizing, and supplementary hydrorefining to obtain a three-stage hydrotreated product oil; and fractionating the product oil to obtain a fraction above 430℃ to obtain polystyrene white oil. The supplementary hydrorefining uses ZSM-5 as the catalyst support, employing either Pt or Pd as the metal. While this method uses ZSM-5 as the catalyst support, low silica-alumina ratio ZSM-5 powder typically exhibits strong acidity, resulting in high cracking activity as a supplementary refining catalyst, which could affect product yield.

[0008] Naphthenic feedstocks are characterized by high viscosity, high molecular weight, and high content of aromatics, especially polycyclic aromatics, which poses a challenge to hydrorefining catalysts. Summary of the Invention

[0009] To address the aforementioned technical problems, the present invention aims to provide an amorphous silica-alumina-based support, a white oil hydrogenation catalyst, and its preparation method and application. The amorphous silica-alumina-based support has a high specific surface area, large pore volume and pore size, numerous acidic active sites, a high total amount of weak acids, and slightly stronger boron acidity. The white oil hydrogenation catalyst exhibits high dispersion of active metals and good catalytic performance.

[0010] To achieve the above objectives, the present invention provides a method for preparing an amorphous silicon-aluminum based carrier, comprising the following steps:

[0011] S1: Amorphous silicon-aluminum materials were prepared using silicon and aluminum sources;

[0012] S2: Boric acid and urea are used sequentially to modify the amorphous silicon-aluminum material to obtain the amorphous silicon-aluminum based carrier.

[0013] In this invention, boric acid modification can improve the acidity of the amorphous silica-alumina-based support and the catalyst prepared therefrom, and urea modification can improve the dispersion of active metals on the amorphous silica-alumina-based support.

[0014] In the above-mentioned method for preparing amorphous silicon-aluminum based carrier, preferably, the method for preparing the amorphous silicon-aluminum material of S1 includes: stirring and mixing silica sol and aluminum sol to form a gel, drying and calcining the gel to obtain the amorphous silicon-aluminum material.

[0015] In the above-described method for preparing amorphous silicon-aluminum based supports, preferably, the mass ratio of silicon source (based on SiO2) to aluminum source (based on Al2O3) is 3:7-5:5. Controlling the silicon-aluminum ratio within this range can improve the acidity of the amorphous silicon-aluminum material and the amorphous silicon-aluminum based support.

[0016] In the above-mentioned method for preparing amorphous silica-alumina-based carriers, preferably, the drying conditions of the gel are: vacuum drying at a temperature of 60-120℃ for 6-24 hours, more preferably drying at a temperature of 110℃ for 10 hours.

[0017] In the above-mentioned method for preparing amorphous silica-alumina-based supports, preferably, the gel is calcined at 400-600℃ for 3-5 hours, more preferably at 500℃ for 3 hours. This calcination step removes impurities from the material, opens up the active pore structure, increases the specific surface area of ​​the material, improves the performance of the prepared amorphous silica-alumina material and the amorphous silica-alumina-based support, and thus enhances the catalytic activity of the catalyst.

[0018] In the above-mentioned method for preparing amorphous silica-alumina-based carriers, preferably, the method for preparing aluminum sol using an aluminum source includes: mixing and stirring boehmite, nitric acid and water at a temperature of 40-90°C to obtain aluminum sol; wherein, the molar ratio of nitric acid to deionized water is 0.1-0.5:1, preferably 0.3:1, and the mass ratio of deionized water to boehmite is 5-50:1, preferably 10:1.

[0019] In the above-mentioned method for preparing amorphous silica-alumina-based carriers, preferably, the method for preparing silica sol using a silicon source includes: mixing and stirring a tetraethyl or ...

[0020] In the above-mentioned method for preparing amorphous silicon-aluminum based carriers, preferably, S1 specifically includes the following steps:

[0021] Aluminum sol was obtained by mixing boehmite, deionized water and nitric acid and stirring at 75°C for 2 hours, wherein the mass ratio of boehmite to deionized water was 1:10 and the molar ratio of nitric acid to deionized water was 0.3:1.

[0022] Silica sol is obtained by mixing and stirring a tetraethyl or ...

[0023] Silica sol was added to aluminum sol and stirred vigorously to form a gel. The gel was then vacuum dried at 110°C for 10 hours (vacuum degree less than 80 mmHg) and then calcined at 500°C for 3 hours to obtain amorphous silicon-aluminum material.

[0024] In the above-mentioned method for preparing amorphous silicon-aluminum based carrier, preferably, the boric acid modification process of S2 includes: impregnating the amorphous silicon-aluminum material with a boric acid solution in equal volume, removing the solid after impregnation and drying and calcining to obtain the boric acid modified carrier.

[0025] In the above-mentioned method for preparing amorphous silica-alumina-based carriers, preferably, in the boric acid modification, the mass ratio of boric acid to amorphous silica-alumina carrier is 0.01-0.03:1, more preferably 0.02:1.

[0026] In the above-mentioned method for preparing amorphous silicon-aluminum based supports, preferably, in the boric acid modification, the calcination temperature is 450-550℃ and the calcination time is 3-8h. More preferably, the rate of heating to the calcination temperature is 1℃ / min.

[0027] In the above-mentioned method for preparing amorphous silica-alumina-based carriers, preferably, in the boric acid modification, the drying conditions include drying at 60°C for 24 hours.

[0028] In the above-mentioned method for preparing amorphous silica-alumina-based carrier, preferably, the urea modification process of S2 includes: mixing and grinding urea with the boric acid modified carrier, calcining the resulting mixed particles in a closed state in two stages, and washing them to obtain the carrier.

[0029] In the above-mentioned method for preparing amorphous silica-alumina-based supports, preferably, in the urea modification, the mass ratio of urea to boric acid-modified support is 0.35-0.45:1, more preferably 0.4:1. Urea modification can significantly improve the active metal dispersion of the amorphous silica-alumina-based support and enhance the activity of the white oil hydrogenation catalyst.

[0030] In the above-mentioned method for preparing amorphous silicon-aluminum based carriers, preferably, in the urea modification, the particle size of the mixed particles after grinding is 240-320 mesh.

[0031] In the above-mentioned method for preparing the amorphous silica-alumina-based carrier, preferably, in the urea modification, the first stage calcination temperature is 120-180℃, and the calcination time is 2-5 h; the second stage calcination temperature is 280-320℃, and the calcination time is 2-5 h. More preferably, the heating rate to both the first and second stage calcination temperatures is 1℃ / min. More preferably, the washing solution used to wash the calcined product is water and alcohol.

[0032] The present invention also provides an amorphous silicon-aluminum based carrier obtained by the above-mentioned method for preparing the amorphous silicon-aluminum based carrier.

[0033] Preferably, the amorphous silicon-aluminum based carrier has a specific area of ​​371-442 m². 2 ·g -1 The pore size is 11.4-13.6 nm, and the pore volume is 1.22-1.56 cm³. 3 ·g -1 .

[0034] The present invention also provides a white oil hydrogenation catalyst, which comprises the above-mentioned amorphous silica-alumina-based support and an active metal, wherein the active metal comprises platinum and palladium.

[0035] In the above-mentioned white oil hydrogenation catalyst, preferably, based on the total mass of the white oil hydrogenation catalyst, the content of platinum is 0.1-0.4 wt% and the content of palladium is 0.2-0.4 wt%.

[0036] The present invention also provides a method for preparing the above-mentioned white oil hydrogenation catalyst, which includes the following steps:

[0037] The amorphous silica-alumina-based support was impregnated in an equal volume of a mixed solution containing a platinum source and a palladium source. After impregnation, the solid was removed, dried, and calcined, thereby loading the platinum and palladium active metals onto the amorphous silica-alumina-based support to obtain the white oil hydrogenation catalyst.

[0038] In the above-mentioned method for preparing white oil hydrogenation catalyst, preferably, the platinum source is selected from tetraammineplatinum nitrate and / or chloroplatinic acid, and the palladium source is selected from palladium nitrate and / or palladium acetate.

[0039] In the above-mentioned method for preparing the white oil hydrogenation catalyst, preferably, the drying conditions include drying at 80-120°C for 4-8 hours; the calcination conditions include calcination at 320-360°C for 5-8 hours. More preferably, the drying conditions include drying at 100°C for 5 hours; the calcination conditions include calcination at 350°C for 6 hours.

[0040] This invention provides a simple and safe method for preparing an amorphous silica-alumina-based polystyrene white oil hydrogenation catalyst. The white oil hydrogenation catalyst prepared by this method has an excellent pore structure (high specific surface area, large pore size), enhanced Brønsted acidity, and highly dispersed active metal.

[0041] The present invention also provides the application of the above-mentioned amorphous silica-alumina-based support or the above-mentioned white oil hydrogenation catalyst in the production of polystyrene white oil from refined cycloalkyl base oil.

[0042] In the above applications, preferably, the naphthenic base oil is the 380-560℃ fraction of naphthenic triple-line oil after hydrorefining and hydroisomerization. The raw material for the hydrorefining of polystyrene white oil in this invention is: a heavy oil fraction of naphthenic oil after hydrorefining and hydroisomerization, with a distillation range of 380-560℃, a 5% fraction point carbon number greater than 22, a naphthenic carbon percentage greater than 32, and a pour point of -22℃.

[0043] In the above applications, preferably, the hydrogenation catalytic reaction conditions include: a reaction temperature of 230-260℃, a reaction pressure of 12-16 MPa, and a volume hourly space velocity of 0.4-1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500-1000:1, more preferably 600:1.

[0044] For naphthenic oils with high viscosity, high molecular weight and high content of polycyclic aromatic hydrocarbons, the heavy fraction of naphthenic oil can be refined into polystyrene white oil using the white oil hydrogenation catalyst of the present invention and the above-mentioned hydrogenation catalytic reaction conditions.

[0045] In the above applications, preferably, the white oil hydrogenation catalyst is reduced before catalysis. The reduction conditions for the catalyst include: pressure 1 MPa, temperature constant at 250℃ for 4 hours, temperature constant at 380℃ for 8 hours, and hydrogen flow rate of 20 L / h.

[0046] Using the white oil hydrogenation catalyst of this invention, the viscosity of the naphthenic white oil product after hydrogenation refining is 76.7 mm at 40°C. 2 / S, with a water-white appearance, excellent oxidation stability and light and heat stability, the product's polycyclic aromatic hydrocarbon ultraviolet absorbance is <0.1, Sacetylene +30, easy carbonization, low pour point, flash point greater than 240℃, and low evaporation loss. Its properties meet the index requirements of polystyrene white oil.

[0047] The amorphous aluminum silicate material of this invention is prepared by the sol-gel method. Through hydrolysis and polycondensation, it gradually gels to form aluminum sol and silica sol, which are then mixed uniformly to form an ASA sol. Following aging, washing, drying, shaping, and calcination, the amorphous aluminum silicate material is obtained. The control of the synthesis conditions and the carrier composite modification method are the main factors affecting the catalyst performance of this invention.

[0048] The technical solution provided by this invention has the following beneficial effects:

[0049] The white oil hydrogenation catalyst prepared by this invention has the characteristics of high specific surface area, large pore volume, and large pore size, possessing a beneficial pore structure. Furthermore, the white oil hydrogenation catalyst has numerous acidic active sites, a high total amount of weak acids, a high content of Brønsted acid (B acid), and strong Brønsted acid. In some specific embodiments, the specific surface area of ​​the white oil hydrogenation catalyst reaches 442 m². 2 / g, pore volume 1.56cm 3 / g, pore size 13.6nm.

[0050] The white oil hydrogenation catalyst prepared by this invention has high metal dispersion. In some specific embodiments, the proportion of supported Pt-Pd active metal particles with a particle size of 2-3 nm is 71%. Attached Figure Description

[0051] Figure 1 Wide-angle XRD spectra of the amorphous aluminum silicate (ASA) material and the modified amorphous aluminum silicate-based support (BN-ASA) of Example 1;

[0052] Figure 2 The N2- adsorption-desorption isotherm of the boric acid-urea modified amorphous silica-alumina support (BN-ASA support) prepared in Example 1;

[0053] Figure 3 The pore size distribution diagram of the boric acid-urea modified amorphous silica-alumina support (BN-ASA support) prepared in Example 1 is shown.

[0054] Figure 4A The images show the pyridine infrared (Py-IR) images of the B-ASA carrier (obtained in step four) and the BN-ASA carrier (obtained in step five) of Example 1 at 150°C.

[0055] Figure 4BThe images show the pyridine infrared (Py-IR) images of the B-ASA carrier (obtained in step four) and the BN-ASA carrier (obtained in step five) of Example 1 at 350°C.

[0056] Figure 5A The active metal particle size distribution of the catalyst DCat-4 (unmodified) in Comparative Example 4 is shown.

[0057] Figure 5B The active metal particle size distribution of the catalyst DCat-2 (urea modified only) in Comparative Example 2 is shown.

[0058] Figure 5C This is a particle size distribution diagram of the active metal in the catalyst Cat-1 (modified with boric acid and urea) of Example 1. Detailed Implementation

[0059] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0060] Example 1

[0061] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which includes the following steps:

[0062] Step 1: Weigh 102g of boehmite, dissolve 1049g of nitric acid in 1000g of deionized water, add boehmite to the nitric acid solution while mechanically stirring at 75℃ until the solution is homogeneous to obtain aluminum sol.

[0063] Step 2: Dissolve 180g of deionized water and 60ml of dilute nitric acid in 46g of anhydrous ethanol to obtain solution A; weigh 299g of tetraethyl orthosilicate, dissolve it in 10.5g of ethanol, and stir until fully miscible to obtain solution B; add sol A to solution B at a controlled speed of 20ml / min under vigorous stirring, and continue stirring for 30 minutes to obtain silica sol;

[0064] Step 3: Add the silica sol prepared in Step 2 to the aluminum sol while adding dropwise and stirring at a mechanical stirring speed of 400 r / min. After the addition is completed, continue stirring for 30 min to obtain a mixed gel. Place the obtained mixed gel into a crystallization kettle, vacuum dry at 110℃ for 10 h, and calcine at 500℃ for 3 h to obtain an amorphous aluminosilicate material, denoted as ASA material.

[0065] Step 4: Prepare the amorphous silicon-aluminum material from Step 3 into a catalyst support: Take 50g of amorphous silicon-aluminum-based support and prepare 105ml of 0.16mol / L boric acid solution. Impregnate the amorphous silicon-aluminum material with the boric acid solution in equal volume. Then dry it in an oven at 60℃ for 24h and calcine it in a muffle furnace at 500℃ for 3h to obtain the boric acid modified support, denoted as B-ASA support.

[0066] Step 5: Take 50g of boric acid modified carrier and 20g of urea, mix and grind to 300 mesh, place in a sealed crucible and calcine at 150℃ for 2h, then calcine at 300℃ for 2h to obtain the boric acid-urea modified amorphous silica-alumina-based carrier, denoted as BN-ASA carrier.

[0067] Step Six: Dissolve 0.265g of chloroplatinic acid in 10g of deionized water to prepare a solution, and dissolve 0.379g of palladium nitrate in 10g of deionized water to prepare a solution. Mix the two metal solutions, add water until the mass of the mixed solution reaches 40g, and use this solution to vacuum impregnate 50g of the amorphous silica-alumina-based support (BN-ASA support) obtained in Step Five. At the same time, ultrasonically disperse for 30min, dry at 100℃ for 5h, calcine at 350℃ for 6h, and then cool to room temperature to obtain the Pt-Pd-supported amorphous silica-alumina-based white oil hydrogenation catalyst.

[0068] The weight percentages of the components in the white oil hydrogenation catalyst prepared in this embodiment are SiO2:Al2O3:Pt:Pd = 39:60.4:0.25:0.35. This catalyst is designated as Cat-1.

[0069] Figure 1 The wide-angle XRD results are for the amorphous aluminum silicate (ASA) material and the modified amorphous aluminum silicate substrate (BN-ASA) of Example 1.

[0070] The testing method was as follows: Phase analysis of the synthesized sample was performed using a Rigaku Corporation 2500 X-ray diffractometer. The scanning range was 5–75°. The experimental conditions were: Cu Kα rays, tube voltage 50 kV, tube current 20 mA, scanning speed 3° / min, and step size 0.02°.

[0071] Depend on Figure 1 It can be seen that the amorphous aluminum silicate material (ASA) in Example 1 has a diffuse peak of silica at 20°-30°, a characteristic peak of boehmite at 28°, 38° and 48°, and a characteristic peak of γ-alumina at 67°. From the XRD spectrum, it can be seen that the support is amorphous aluminum silicate powder. The amorphous aluminum silicate-based material (BN-ASA) after modification with boric acid and then urea still has the characteristic peaks of amorphous aluminum silicate powder. Compared with the unmodified material, the position, peak height and peak intensity of the characteristic peaks are basically unchanged. The support after modification is also in an amorphous aluminum silicate state.

[0072] Figure 2 This is the N2- adsorption-desorption isotherm diagram of the amorphous silica-alumina-based support (BN-ASA) of Example 1. Figure 2 It can be seen that the boric acid-urea modified amorphous silicon-aluminum substrate (BN-ASA) in Example 1 has a type IV isothermal adsorption-desorption isotherm and a type H1 hysteresis loop, indicating that this material has a relatively concentrated distribution of mesoporous channels.

[0073] Figure 3 This is a pore size distribution diagram of the amorphous silicon-aluminum substrate (BN-ASA) in Example 1. Figure 3 It can be seen that the boric acid-urea modified amorphous silicon-aluminum substrate (BN-ASA) in Example 1 has wide channels and concentrated pore size distribution.

[0074] Example 2

[0075] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, prepared using the same method as in Example 1, except that tetraethyl orthosilicate is used as the silicon source, with an amount of 236g, to prepare a silica sol. This catalyst is designated Cat-2.

[0076] Example 3

[0077] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, prepared using the same method as in Example 1, except that in step one, activated alumina powder is used instead of boehmite to prepare an alumina sol. This catalyst is designated Cat-3.

[0078] Example 4

[0079] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which is the same as that of Example 1, except that the amount of 0.16 mol / L boric acid solution used in step four is 50.5 ml.

[0080] The catalyst prepared in this embodiment is designated as Cat-4.

[0081] Example 5

[0082] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which is the same as that of Example 1, except that the amount of 0.16 mol / L boric acid solution in step four is 151.5 ml.

[0083] The catalyst prepared in this embodiment is designated as Cat-5.

[0084] Example 6

[0085] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which is the same as that of Example 1, except that the amount of urea used in step five is 17.5g.

[0086] The catalyst prepared in this embodiment is designated as Cat-6.

[0087] Example 7

[0088] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which is the same as that of Example 1, except that the amount of urea used in step five is 22.5g.

[0089] The catalyst prepared in this embodiment is designated as Cat-7.

[0090] Example 8

[0091] This embodiment provides a white oil hydrogenation catalyst, which is prepared using the amorphous silica-alumina-based support of Example 1. The preparation method of the white oil hydrogenation catalyst in this embodiment includes the following steps:

[0092] 0.265g of chloroplatinic acid was dissolved in 10g of deionized water to prepare a solution, and 0.369g of palladium acetate was dissolved in 10g of deionized water to prepare a solution. The amorphous silica-alumina-based support of Example 1 was impregnated with the mixed solution and ultrasonically dispersed for 30min. The solution was then dried at 100℃ for 5h, calcined at 350℃ for 6h, and cooled to room temperature to obtain the white oil hydrogenation catalyst.

[0093] The catalyst is designated Cat-8.

[0094] Example 9

[0095] This embodiment provides a white oil hydrogenation catalyst, which is prepared using the amorphous silica-alumina-based support of Example 1. The preparation method of the white oil hydrogenation catalyst in this embodiment includes the following steps:

[0096] 0.248 g of tetraammineplatinum nitrate was dissolved in 10 g of deionized water to prepare a solution, and 0.369 g of palladium acetate was dissolved in 10 g of deionized water to prepare a solution. The amorphous silica-alumina-based support of Example 1 was impregnated with the solution and ultrasonically dispersed for 30 min. After drying at 100 °C for 5 h and calcining at 350 °C for 6 h, the solution was cooled to room temperature to obtain the white oil hydrogenation catalyst.

[0097] The catalyst is designated Cat-9.

[0098] Example 10

[0099] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, prepared using the same method as in Example 1, with the only difference being: Step 1: Weigh 51g of boehmite and dissolve 522g of nitric acid in 1000g of deionized water to prepare an aluminum sol; Step 2: Dissolve 180g of deionized water and 60ml of dilute nitric acid sequentially in 46g of anhydrous ethanol to obtain solution A; weigh 149.6g of tetraethyl orthosilicate and dissolve it in 5.2g of ethanol, stirring until fully miscible to obtain solution B, thus preparing a silica sol. The white oil hydrogenation catalyst is then prepared.

[0100] The catalyst prepared in this embodiment is designated as Cat-10.

[0101] Example 11

[0102] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, prepared using the same method as in Example 1, with the only difference being: Step 1: Weigh 510g of boehmite and dissolve 1748g of nitric acid in 1000g of deionized water to prepare an aluminum sol; Step 2: Dissolve 180g of deionized water and 60ml of dilute nitric acid sequentially in 46g of anhydrous ethanol to obtain solution A; weigh 1496g of tetraethyl orthosilicate and dissolve it in 52.5g of ethanol, stirring until fully miscible to obtain solution B, thus preparing a silica sol. The white oil hydrogenation catalyst is then prepared.

[0103] The catalyst prepared in this embodiment is designated as Cat-11.

[0104] Example 12

[0105] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which is the same as that of Example 1, except that: Step 2: 180g of deionized water and 60ml of dilute nitric acid are dissolved in 46g of anhydrous ethanol to prepare solution A; 299g of tetraethyl orthosilicate is weighed and dissolved in 52g of ethanol, and stirred to make it fully miscible to obtain solution B; solution A is added to solution B under vigorous stirring to prepare silica sol.

[0106] The catalyst prepared in this embodiment is designated as Cat-12.

[0107] Example 13

[0108] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which is the same as that of Example 1, except that: Step 2: 180g of deionized water and 60ml of dilute nitric acid are dissolved in 46g of anhydrous ethanol to obtain solution A; 299g of tetraethyl orthosilicate is weighed and dissolved in 5.2g of ethanol, and stirred to make it fully miscible to obtain solution B; solution A is added to solution B under vigorous stirring to prepare silica sol.

[0109] The catalyst prepared in this embodiment is designated as Cat-13.

[0110] Example 14

[0111] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which is the same as that of Example 1, except that: Step 2: 360g of deionized water and 221ml of dilute nitric acid are dissolved in 46g of anhydrous ethanol to prepare solution A; 299g of tetraethyl orthosilicate is weighed and dissolved in 10.5g of ethanol, and stirred to make it fully miscible to obtain solution B; solution A is added to solution B under vigorous stirring to prepare silica sol.

[0112] The catalyst prepared in this embodiment is designated as Cat-14.

[0113] Example 15

[0114] This embodiment provides an amorphous silica-alumina-based support and a white oil hydrogenation catalyst, the preparation method of which is the same as that of Example 1, except that: Step 2: 90g of deionized water and 22ml of dilute nitric acid are dissolved in 46g of anhydrous ethanol to obtain solution A; 299g of tetraethyl orthosilicate is weighed and dissolved in 10.5g of ethanol, and stirred to make it fully miscible to obtain solution B; solution A is added to solution B under vigorous stirring to prepare silica sol.

[0115] The catalyst prepared in this embodiment is designated as Cat-15.

[0116] Comparative Example 1

[0117] This comparative example provides an amorphous silicon-aluminum-based support and a hydrogenation refining catalyst, the preparation method of which is the same as that of Example 1, except that steps one to three in Example 1 are replaced with the method disclosed in Example 1 of CN201310499346.6 to prepare the amorphous silicon-aluminum material.

[0118] The catalyst prepared in this comparative example is denoted as DCat-1.

[0119] Comparative Example 2

[0120] This comparative example provides an amorphous silica-alumina-based support and a hydrorefining catalyst, prepared using the same method as in Example 1, except that step four of Example 1 is omitted. Specifically, 50g of the amorphous silica-alumina material from Example 1 is modified with urea to prepare the support, denoted as the N-ASA support.

[0121] The catalyst prepared in this comparative example is denoted as DCat-2.

[0122] Comparative Example 3

[0123] This comparative example provides an amorphous silica-alumina-based support and a hydrogenation refining catalyst, the preparation method of which is the same as that of Example 1, except that step five of Example 1 is not performed in this comparative example.

[0124] The catalyst prepared in this comparative example is denoted as DCat-3.

[0125] Comparative Example 4

[0126] This comparative example provides an amorphous silica-alumina-based support and a hydrogenation refining catalyst, the preparation method of which is the same as that of Example 1, except that: this comparative example does not perform steps four and five of Example 1, that is, the catalyst is prepared by directly loading the active metal onto the ASA material of Example 1.

[0127] The catalyst prepared in this comparative example is designated DCat-4.

[0128] The specific surface area, pore size, and pore volume of the amorphous silica-alumina carriers prepared in Examples 1-15 and Comparative Examples 1-4 were measured, and the results are shown in Table 1 below.

[0129] Table 1. Structural Properties of Amorphous Aluminosilicate Carriers

[0130]

[0131]

[0132] As shown in Table 1, the amorphous aluminosilicate support (BN-ASA support) prepared in Example 1 has a large specific surface area, pore volume, and pore size, making it suitable for hydrogenation saturation of large-molecule polycyclic aromatic hydrocarbons. Compared with Examples 1-15 of the present invention, the amorphous aluminosilicate support synthesized in Comparative Example 1 has the smallest specific surface area, pore volume, and pore size. The amorphous aluminosilicate support prepared in Comparative Example 2, without boric acid modification, has a smaller pore volume and pore size. The amorphous aluminosilicate support prepared in Comparative Example 3, without urea modification, has a smaller specific surface area. The unmodified amorphous aluminosilicate support prepared in Comparative Example 4 has a smaller specific surface area, pore volume, and pore size.

[0133] Figure 4A , Figure 4B Table 2 shows the pyridine infrared (Py-IR) images of the B-ASA support (obtained in step four) and the BN-ASA support (obtained in step five) of Example 1. Table 2 shows the pyridine infrared (Py-IR) results of the ASA material (obtained in step three), B-ASA support (obtained in step four), BN-ASA support (obtained in step five) of Example 1, and the N-ASA support of Comparative Example 2. The test method is as follows:

[0134] The acid type of the catalyst was quantitatively characterized using a Digilab FTIR spectrometer. Experimental method: Approximately 10 mg of catalyst powder was pressed into tablets, placed in an in-situ cell, and incubated under vacuum (1×10⁻⁶) at 350 °C. -3 (Pa) Pretreatment for 2 h, followed by cooling to room temperature and then background scanning. After pyridine adsorption for approximately 20 min, the temperature was programmed to rise to 150 °C, followed by desorption at 350 °C for 30 min, and infrared signals were recorded. The acid content measured at 150 °C desorption represents the total acid content of the sample, while the acid content measured at 350 °C desorption represents the sum of the amounts of moderately strong and strong acids. After pyridine adsorption, Brønsted (B) acid and Lewis (L) acid were measured at 1450 cm⁻¹. -1 and 1540cm -1 Infrared absorption occurs in the vicinity.

[0135] Table 2. Pyridine infrared (Py-IR) results for ASA-based supports

[0136]

[0137] Table 2 shows that, compared with the unmodified support, the boric acid-modified support and the white oil hydrogenation catalyst prepared therefrom exhibit increased Brønsted acid content, decreased Lewis acid content, increased total weak acid content, and decreased total strong acid content. The changes in acidic sites and acid content on the amorphous silica-alumina-based support and the white oil hydrogenation catalyst prepared after boric acid and urea modification are beneficial for the adsorption of aromatics in viscous, high-molecular-weight heavy oils, while minimizing alkane cracking, resulting in better catalyst activity.

[0138] Figure 5A The image shows the particle size distribution of the active metal in the catalyst DCat-4 (unmodified) of Comparative Example 4. Figure 5B The image shows the particle size distribution of the active metals in the catalyst DCat-2 (urea modified only) of Comparative Example 2. Figure 5C This is a particle size distribution diagram of the active metal in the catalyst Cat-1 (modified with boric acid and urea) of Example 1.

[0139] The testing method is as follows: Transmission electron microscopy (TEM) is used to analyze the pore structure of the sample and the active phase on the catalyst surface. A portion of the area is taken and compared to obtain the distribution data of active metal particles of the catalyst after unmodification, amination modification and boric acid-urea modification. The data are then plotted.

[0140] The comparison showed that the active metal particles of Pt and Pd in ​​the catalysts that were not modified by amination (urea) were larger, while the Pt and Pd particles in the catalysts that were modified by amination were more distributed with a diameter of 2-3 nm. This indicates that the white oil hydrogenation catalyst prepared by amination modification has the characteristics of uniform dispersion of active metal and small particle size.

[0141] Experimental Example 1

[0142] This experimental example is used to evaluate the white oil hydrogenation catalytic performance of the catalysts in the above examples and comparative examples.

[0143] The properties of the naphthenic feedstock used in white oil hydrogenation are shown in Table 3. The naphthenic triple-line oil is hydrorefined and hydroisomerized, and the heavy fraction with a temperature >380℃ after fractionation is used as the feedstock for white oil hydrogenation.

[0144] Table 3. Partial Properties of Naphthenic Reduced Triple Line >380℃ Base Oils

[0145] raw material Naphthenic-based triple-line base oils (>380℃ fraction) <![CDATA[Density (20 °C), g / cm 3 > 0.8737 S, ug / g <1.0 N, ug / g <1.1 <![CDATA[Viscosity at 40°C, mm 2 / S]]> 82.05 <![CDATA[Viscosity at 100 °C, mm 2 / S]]> 8.32 Sticky fingers 57 Aromatics, wt% 1.95 Flash point (open cup), ℃ 242 Pour point, ℃ -21 CN 33.2 CP 66.8

[0146] The distillate oil after hydrorefining and hydroisomerization using cycloalkyl triple-line hydrotreating was used as the feed oil after distillation at temperatures above 380°C. The catalysts prepared in the embodiments and comparative examples of this invention were used as white oil hydrotreating catalysts. The performance of white oil hydrotreating was evaluated by optimizing the hydrotreating reaction conditions.

[0147] Catalyst testing conditions: catalyst quantity 50 ml; catalyst reduction conditions: pressure 1 MPa, temperature constant at 250℃ for 4 h, then constant at 380℃ for 8 h, hydrogen flow rate 20 L / h; hydrogenation reaction conditions: reaction temperature 230-260℃, pressure 12-16 MPa, volume hourly space velocity 0.4-1.0 h⁻¹ -1 The hydrogen-to-oil volume ratio is 600:1.

[0148] The catalytic results are shown in Table 4.

[0149] Table 4. Partial Properties of Products from Hydrogenation of Naphthenic Distillate Oils Using Catalysts

[0150]

[0151] As shown in Table 4, the hydrogenation effects of Cat-1 to Cat-15 on cycloalkyl distillate oils were all higher than those of Comparative Examples 1, 2, 3 and 4. Among them, Cat-1 had the highest dearomatization performance. The UV absorbance of the dearomatization products of Cat-1 to Cat-15 catalysts was all <0.1 cm, which met the standard for polyolefin white oil.

[0152] Table 5 shows the product property analysis data after hydrorefining of cycloalkyl distillate oil.

[0153] Table 5. Analysis data on the properties of PS white oil products.

[0154]

[0155] As shown in Table 5, the above-mentioned catalyst preparation method, using heavy distillate of cycloalkyl distillate oil as raw material, can produce polystyrene white oil products with the required properties.

Claims

1. A method for preparing an amorphous silicon-aluminum based support, comprising the following steps: S1: Amorphous silicon-aluminum materials were prepared using silicon and aluminum sources; S2: Boric acid and urea are used sequentially to modify the amorphous silicon-aluminum material to obtain the amorphous silicon-aluminum based carrier; in, The boric acid modification process of S2 includes: impregnating the amorphous silicon-aluminum material with boric acid solution in equal volume, removing the solid after impregnation and drying and calcining to obtain the boric acid modified carrier; The urea modification process of S2 includes: mixing and grinding urea with the boric acid modified carrier, calcining the resulting mixed particles in a closed state in two stages, and washing them to obtain the amorphous silicon-aluminum based carrier.

2. The method for preparing the amorphous silicon-aluminum based carrier according to claim 1, wherein, The preparation method of the amorphous silicon-aluminum material of S1 includes: stirring and mixing silica sol and aluminum sol to form a gel, drying and calcining the gel to obtain the amorphous silicon-aluminum material.

3. The method for preparing the amorphous silicon-aluminum based carrier according to claim 2, wherein, The mass ratio of silicon source (calculated as SiO2) to aluminum source (calculated as Al2O3) is 3:7-5:

5.

4. The method for preparing the amorphous silicon-aluminum based carrier according to claim 2, wherein, A method for preparing aluminum sol using an aluminum source includes: mixing and stirring boehmite or alumina powder, nitric acid and water at a temperature of 40-90℃ to obtain aluminum sol; wherein the molar ratio of nitric acid to deionized water is 0.1-0.5, and the mass ratio of deionized water to boehmite is 5-50.

5. The method for preparing the amorphous silicon-aluminum based carrier according to claim 2, wherein, A method for preparing silica sol using a silicon source includes: mixing and stirring an ethanol solution of tetraethyl orthosilicate with a mixture of ethanol, nitric acid, and water at 20-30°C for 10-30 minutes to obtain silica sol; wherein the molar ratio of tetraethyl orthosilicate to ethanol in the ethanol solution is 1-10:1, the molar ratio of ethanol, nitric acid, and water in the mixture is 1:0.5-5:5-20, and the molar ratio of the ethanol solution of tetraethyl orthosilicate to the mixture is 1.2-12.

3.

6. The method for preparing the amorphous silicon-aluminum based carrier according to claim 1, wherein, In boric acid modification, the mass ratio of boric acid to amorphous silica-alumina carrier is 0.01-0.03:

1.

7. The method for preparing the amorphous silicon-aluminum based carrier according to claim 6, wherein, In the boric acid modification, the mass ratio of boric acid to amorphous silica-alumina carrier is 0.02:

1.

8. The method for preparing the amorphous silicon-aluminum based carrier according to claim 1, wherein, In boric acid modification, the calcination temperature is 450-550℃ and the calcination time is 3-8h.

9. The method for preparing the amorphous silicon-aluminum based carrier according to claim 1, wherein, The mass ratio of urea to boric acid modified carrier is 0.35-0.45:

1.

10. The method for preparing the amorphous silicon-aluminum based carrier according to claim 1, wherein, In urea modification, the particle size of the mixed particles after grinding is 240-320 mesh.

11. The method for preparing an amorphous silicon-aluminum based carrier according to claim 1, wherein, In urea modification, the first stage of calcination is carried out at a temperature of 120-180℃ for 2-5 hours; the second stage of calcination is carried out at a temperature of 280-320℃ for 2-5 hours.

12. An amorphous silicon-aluminum based carrier obtained by the preparation method of any one of claims 1-11.

13. The amorphous silicon-aluminum based carrier according to claim 12, wherein, The specific area of ​​the amorphous silicon-aluminum based carrier is 371-442 m². 2 ·g -1 The pore size is 11.4-13.6 nm, and the pore volume is 1.22-1.56 cm³. 3 ·g -1 .

14. A white oil hydrogenation catalyst comprising the amorphous silica-alumina-based support as described in claim 12 or 13 and an active metal, said active metal comprising platinum and palladium.

15. The white oil hydrogenation catalyst according to claim 14, wherein, Based on the total mass of the white oil hydrogenation catalyst, the platinum content is 0.1-0.4 wt% and the palladium content is 0.2-0.4 wt%.

16. A method for preparing the white oil hydrogenation catalyst according to claim 14 or 15, comprising the following steps: The amorphous silicon-aluminum based support of claim 12 or 13 is impregnated in a mixed solution containing a platinum source and a palladium source. After impregnation, the solid is removed, dried, and calcined to obtain the white oil hydrogenation catalyst.

17. The method for preparing the white oil hydrogenation catalyst according to claim 16, wherein the platinum source is selected from tetraammineplatinum nitrate and / or chloroplatinic acid, and the palladium source is selected from palladium nitrate and / or palladium acetate.

18. The use of the amorphous silica-alumina-based support of claim 12 or 13 or the white oil hydrogenation catalyst of claim 14 or 15 in the production of polystyrene white oil from refined naphthenic base oil.

19. The application according to claim 18, wherein the naphthenic base oil is a 380-560°C fraction obtained by hydrorefining and hydroisomerizing naphthenic triplet oil.

20. The application according to claim 18, wherein, The hydrorefining reaction conditions include: a reaction temperature of 230-260℃, a reaction pressure of 12-16 MPa, and a volume hourly space velocity of 0.4-1.0 h⁻¹. -1 The hydrogen-to-oil volume ratio is 500-1000:

1.

21. The application according to claim 18, wherein, The white oil hydrogenation catalyst is reduced before catalysis.

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