A hydroprocessing catalyst, its preparation method and use

Abstract

The application discloses a kind of hydroprocessing catalyst and its preparation method and application.The method comprises the following steps: (1) take aluminium hydroxide dry glue powder and auxiliary agent mix, then join glue solvent;Using kneading or roll-pressing is formed;After drying, calcination is prepared alumina carrier;(2) active metal is introduced on the alumina carrier prepared in step (1), and the final hydroprocessing catalyst is prepared after drying and calcination;Wherein, the drying process in step (1) is carried out under alkaline atmosphere, and the alkaline gas is ammonia, and the volume content of ammonia gas accounts for 2-13% of the volume fraction of drying atmosphere, preferably 3-10%, the hydroprocessing catalyst prepared by the method is particularly suitable for hydroprocessing heavy distillate oil.

Description

Technical Field

[0001] This invention relates to a hydrotreating catalyst, its preparation method, and its application. More specifically, it relates to a hydrotreating catalyst suitable for processing heavy distillate oils, its preparation method, and its application. Background Technology

[0002] As the quality of crude oil worldwide gradually deteriorates, refineries are placing greater emphasis on the deep processing and utilization of heavy crude oil in order to maximize its value.

[0003] Currently, technicians utilize macroporous boehmite powder as a direct carrier or add pore-expanding agents during the carrier molding process to enhance the pore structure of the carrier. CN 96103297.9 discloses a method for preparing a macroporous alumina carrier, which mainly involves mixing physical pore-expanding agents such as carbon black and chemical pore-expanding agents such as phosphides with boehmite, then molding the mixture using a kneading method, and finally drying and calcining it to obtain an alumina carrier with a pore diameter of 15.0–20.0 nm.

[0004] CN 99113271.8 discloses a method for preparing an alumina support with a concentrated pore distribution. A sol is prepared by reacting an aqueous solution of a weak acid containing at least one organic acid with alumina monohydrate. The acidified granular solid is then treated with an alkaline aqueous solution, with the final pH value controlled above 7.5. Following a kneading and extrusion process, and subsequent processing, an alumina support with concentrated pores is obtained.

[0005] CN 103100397 A discloses a method for preparing a hydrogenation catalyst. The preparation of the support mainly involves wetting aluminum hydroxide dry adhesive powder with a wetting solution containing surfactants, mixing or kneading, adding pectinic acid, molding, drying, and calcining to obtain the alumina support. This method helps maintain the original pore structure of the dry adhesive powder and avoids the increase of secondary formed pores.

[0006] Heavy oils have larger molecular sizes and contain more sulfur and nitrogen, requiring higher-performance hydrotreating catalysts. The overall performance of a catalyst is closely related to the type and content of the active metal used, the corresponding preparation method, and the catalyst's pore structure. When the average pore size of the catalyst is too small, the diffusion efficiency is severely limited; conversely, when the pore size is too large, the specific surface area of ​​the catalyst decreases significantly, affecting the intrinsic activity of the supported catalytic metal. The performance of the alumina support greatly influences the pore structure of the catalyst. Therefore, improving the performance of the alumina support is key to comprehensively improving catalyst activity.

[0007] Besides enhancing the intrinsic activity of the catalyst, reducing its packing density can also improve its cost-effectiveness. Alumina support is the main component of the catalyst, and its pore structure directly affects its performance. When the micropore content of the support decreases, the alumina packing density decreases, which in turn promotes an increase in metal loading, thus contributing to improved intrinsic catalyst activity. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a hydrotreating catalyst, its preparation method, and its application. The hydrotreating catalyst prepared by this method is particularly suitable for hydrotreating heavy distillate oils.

[0009] A method for preparing a hydrotreating catalyst, the method comprising the following steps: (1) Mix aluminum hydroxide dry adhesive powder, extrusion aid, and adhesive solvent. Preferably, aluminum hydroxide dry adhesive powder is mixed with the extrusion aid first, and then the adhesive solvent is added. The mixture is formed by kneading or rolling. The aluminum oxide carrier is obtained by drying and calcining. (2) An active metal is introduced onto the alumina support prepared in step (1), and the final hydrogenation catalyst is obtained after drying and calcination. The drying process described in step (1) is carried out under an alkaline atmosphere, wherein the alkaline gas is ammonia, and the volume content of ammonia accounts for 2 to 13% of the volume fraction of the drying atmosphere, preferably 3 to 10%.

[0010] In the method of this invention, ammonia can be derived from gases produced by the thermal decomposition of ammonia water, urea, ammonium bicarbonate, etc.

[0011] In the method of the present invention, the alkaline gas atmosphere can be introduced at any stage of the drying process, and the drying time under the alkaline atmosphere accounts for 20% to 100% of the total drying time, preferably 30% to 90%. In the method of the present invention, the alkaline gas can be introduced at any stage of drying, preferably at the beginning stage of drying, and the processing time accounts for 35-70% of the total time, most preferably 40-60%.

[0012] The drying temperature of the molded carrier is 90~160℃, and the drying time is 2~8h; the calcination temperature of the carrier is 500~750℃, and the calcination time is 2~7h.

[0013] In the method of this invention, the aluminum hydroxide dry adhesive powder can be a commercially available product or boehmite produced using any existing preparation technology, such as the carbonization method or the aluminum sulfate method. The powder can be pure aluminum hydroxide powder or aluminum hydroxide powder containing additives, which can be one or more of silicon, titanium, zinc, magnesium, boron, phosphorus, fluorine, and zirconium.

[0014] In the powder mixing process of this invention, molding aids such as extrusion aids, alumina powder, other aluminum hydroxide powders, and other additives required for the catalyst can be introduced. The amount added is adjusted and determined according to the performance requirements of the catalyst. Extrusion aids are one or more commonly used in the art, including starch, polyvinyl alcohol, polyacrylamide, methylcellulose, and guar gum powder.

[0015] In the method of this invention, the colloidal solvent can be various organic acids, inorganic acids, and acids that can ionize to release H+. ＋ The compounds used, such as nitric acid, hydrochloric acid, oxalic acid, acetic acid, propionic acid, and ammonium dihydrogen phosphate, are colloids, and the colloid solvents used are one or more of the above substances.

[0016] The aluminum hydroxide material described in the above method, whether kneaded or crushed, can be extruded using existing techniques in the art. Depending on the catalyst requirements, it can be made into various shapes, such as spheres, tablets, rings, hollow cylinders, or strips. Strips (cloverleaf, four-leaf clover, cylindrical strips, etc.) are preferred, and different sizes can be produced as needed.

[0017] The properties of the alumina carrier of the present invention are as follows: the ratio of the pore volume content of >15nm to the pore volume content of <4nm is 4.5~15.5, preferably 6.0~13.5, and most preferably 9.0~12.5.

[0018] The active metal component of the hydrogenation catalyst of this invention can be a Group VIB or / and Group VIII metal, with molybdenum and / or tungsten being preferred Group VIB metals, and nickel being preferred Group VIII metals. It can be a salt, oxide, or acid containing the corresponding element, such as molybdenum typically derived from one or more of molybdenum oxide, ammonium molybdate, and ammonium paramolybdate; tungsten typically derived from ammonium metatungstate; and nickel derived from one or more of nickel nitrate, nickel carbonate, basic nickel carbonate, and nickel oxalate. The metal solution is prepared using methods well known to those skilled in the art.

[0019] In the above method, the active metal component is loaded onto the carrier by impregnation. Equal-volume impregnation or excessive impregnation can be used; stepwise impregnation or co-impregnation can be employed, with equal-volume co-impregnation being preferred. The drying and calcination processes after impregnation are performed under conventional conditions used in the art. The drying temperature is 80–190°C, and the drying time is 4–16 h; the calcination temperature is 400–600°C, and the calcination time is 2–6 h.

[0020] A hydrogenation catalyst prepared by the above method, by weight of the catalyst, contains 10-30 wt% of Group VIB metal oxide and 2-10 wt% of Group VIII metal oxide.

[0021] According to publicly available technologies, the preparation of alumina carriers from boehmite powder inevitably involves acidic colloidal solutions. During the material crushing or kneading process, the acidic solution dissolves some of the boehmite, forming a colloidal binder. Through a pressure molding process, carriers of various shapes can be formed. During the drying process before calcination, the carrier is still aging, and the residual acid solution continues to exert a colloidal effect, especially for raw material powders with good colloidal properties, which are more sensitive to acid. The binder formed in the above process is the main source of small-sized pores in the carrier. The acid solution before mixing and molding is crucial for the carrier's molding effect and high strength; therefore, it is difficult to fundamentally avoid the small pores caused by this colloidal process. However, controlling the colloidal process from molding to calcination can effectively reduce the formation of small pores.

[0022] In the preparation of the alumina carrier of this invention, aluminum hydroxide dry adhesive powder is mixed with additives and molded into a plastic body under the action of a solvent. An alkaline gas atmosphere is introduced during the drying process, followed by calcination to obtain the alumina carrier. The drying process under an alkaline atmosphere has the following advantages: firstly, it can neutralize the residual acid in the bulk phase, reducing the erosion of the powder's pore structure by the acid and thus helping to maintain the pore structure; secondly, some of the aluminum sol that did not act as a binder reconstructs the pore structure of the aluminum hydroxide dry adhesive under alkaline conditions, which helps to reduce the content of small pores in the carrier.

[0023] The overall pore structure of the support is optimized, which is more conducive to the dispersion of active metals and improves the utilization rate of active metals. The density of the alumina skeleton after calcination is reduced, resulting in a lower packing density of the catalyst made using this support. The reduced micropore content in the catalyst helps to improve the diffusion efficiency of reactants and also facilitates the deposition of impurities during the hydrotreating of heavy oil, thereby enhancing the activity and stability of the catalyst. Implementation

[0024] The technical solution of the present invention will be further illustrated below through embodiments and comparative examples. It should be understood that the specific embodiments described are limited to illustrating and explaining the present invention and are not intended to limit the present invention.

[0025] In the following examples, the pore structure properties of the calcined alumina support and catalyst were determined using a low-temperature nitrogen physical adsorption method.

[0026] The pore structure properties of the aluminum hydroxide dry adhesive powder used in the examples are shown in Table 1.

[0027] Table 1. Pore structure of aluminum hydroxide dry adhesive powder used in the examples.

[0028] Example 1 The molding process of aluminum hydroxide dry adhesive powder is as follows: Following methods well-known to those skilled in the art, 94g of cellulose and 88g of guar gum powder are weighed and added to 4000g of aluminum hydroxide dry adhesive powder, and mixed in a mill for 10 minutes. After homogenization, 4235g of a 3.0wt% dilute nitric acid solution is uniformly added dropwise to the powder. Then, the powder is milled in a mill for 30 minutes, and the plastic body is extruded into strips using a 1.7mm diameter cloverleaf perforated plate, denoted as ST.

[0029] Example 2 Drying and calcination process of the molded carrier: The molded carrier ST was transferred to a drying oven at 115℃, and ammonia gas with a volume fraction of 6.5% was directly introduced and maintained throughout the drying process for 5 hours. The carrier after calcination at 580℃ for 4 hours was designated as ZT-1.

[0030] Catalyst preparation process: Based on the weight of the catalyst, 3.5% is nickel oxide and 21.2% is nickel oxide, which are used to prepare a molybdenum-nickel metal solution. The solution is impregnated with an equal volume of support ZT-1, dried at 120℃ for 4 hours, and calcined at 500℃ for 2 hours to obtain the hydrogenation treatment catalyst CT-1.

[0031] Example 3 Drying and calcination process of the molded carrier: The molded carrier ST was transferred to a drying oven at 115℃, and ammonia gas with a volume fraction of 4% was directly introduced for drying for 4 hours. Then, the drying conditions were switched to conventional drying conditions, and drying continued for 2 hours. The carrier after calcination at 580℃ for 4 hours was designated as ZT-2.

[0032] Catalyst preparation process: Based on the weight of the catalyst, 3.5% is nickel oxide and 21.2% is nickel oxide, which are used to prepare a molybdenum-nickel metal solution. The solution is impregnated with an equal volume of support ZT-2, dried at 120℃ for 4 hours, and calcined at 500℃ for 2 hours to obtain the hydrogenation treatment catalyst CT-2.

[0033] Example 4 Drying and calcination process of the molded carrier: The molded carrier ST was transferred to a drying oven at 115℃, and ammonia gas with a volume fraction of 7% was directly introduced for drying for 3 hours. Then, the drying conditions were switched to conventional conditions, and drying was continued for another 3 hours. The carrier after calcination at 580℃ for 4 hours was designated as ZT-3.

[0034] Catalyst preparation process: Based on the weight of the catalyst, 3.5% is nickel oxide and 21.2% is nickel oxide, which are used to prepare a molybdenum-nickel metal solution. The solution is impregnated with an equal volume of support ZT-3, dried at 120℃ for 4 hours, and calcined at 500℃ for 2 hours to obtain the hydrogenation treatment catalyst CT-3.

[0035] Example 5 Drying and calcination process of the molded carrier: The molded carrier ST was transferred to a drying oven at 115℃, and ammonia gas with a volume fraction of 9% was directly introduced for drying for 2.5 hours. Then, the drying conditions were switched to conventional conditions, and drying continued for another 4 hours. The carrier after calcination at 580℃ for 4 hours was designated as ZT-4.

[0036] Catalyst preparation process: Based on the weight of the catalyst, 3.5% is nickel oxide and 21.2% is nickel oxide, which are used to prepare a molybdenum-nickel metal solution. The solution is impregnated with an equal volume of support ZT-4, dried at 120℃ for 4 hours, and calcined at 500℃ for 2 hours to obtain the hydrogenation catalyst CT-4.

[0037] Example 6 Drying and calcination process of the molded carrier: The molded carrier ST was transferred to a drying oven at 115℃ and dried conventionally for 2.5 hours. Then, ammonia gas with a volume fraction of 9.5% was introduced, and drying continued for another 2.5 hours. The carrier after calcination at 580℃ for 4 hours was designated as ZT-5.

[0038] Catalyst preparation process: Based on the weight of the catalyst, 3.5% is nickel oxide and 21.2% is nickel oxide, which are used to prepare a molybdenum-nickel metal solution. The solution is impregnated with an equal volume of ZT-5 support, dried at 120℃ for 4 hours, and calcined at 500℃ for 2 hours to obtain the hydrogenation treatment catalyst CT-5.

[0039] Comparative Example 1 Drying and calcination process of the molded carrier: The molded carrier ST was transferred to a drying oven at 115℃ and dried for 6 hours using conventional methods. The carrier after calcination at 580℃ for 4 hours was designated as DT.

[0040] Catalyst preparation process: Based on the weight of the catalyst, 3.5% is nickel oxide and 21.2% is nickel oxide, which are used to prepare a molybdenum-nickel metal solution. The solution is impregnated with an equal volume of DT support, dried at 120℃ for 4 hours, and calcined at 500℃ for 2 hours to obtain the hydrogenation treatment catalyst DCT.

[0041] Table 2. Properties of the alumina support in the examples and comparative examples.

[0042] As shown in Table 2, compared with the comparative example, the pore volume of the support prepared by the present invention after alkaline drying treatment is significantly improved. In particular, the content of pores smaller than 4 nm decreases, the content of pores >15 nm increases, and the ratio of the volume content of pores >15 nm to that of pores <4 nm is significantly improved. With the optimization of the pore structure of the support, the packing density of the support is also significantly reduced, but the strength of the support is significantly reduced by continuous ammonia treatment. In addition, the overall performance of the support prepared by direct ammonia drying is better than that of the support prepared by conventional drying followed by alkaline treatment. In summary, by directly introducing ammonia into the drying process and controlling the duration of ammonia introduction, a support with excellent overall performance can be obtained with a smaller amount of ammonia.

[0043] Example 7 This example is an experiment to evaluate the activity of the catalyst: All prepared hydrotreating catalysts were evaluated on a 100 mL small-scale hydrotreating apparatus using vacuum-pressed wax oil as feedstock to assess their hydrodesulfurization and hydrodenitrogenation activities. The operating conditions for the evaluation experiments were: reaction temperature 365 °C, reaction pressure 10.0 MPa, and liquid hourly space velocity (LISH) 1.4 h⁻¹. -1 The hydrogen-to-oil volume ratio was 700:1. The properties of the feedstock oil used in the activity evaluation experiment are shown in Table 3, and the activity evaluation results are shown in Table 4. As can be seen from the data in the tables, the pore volume of the hydrotreating catalyst prepared using the support of this invention is significantly higher than that of the comparative catalyst, and the initial relative denitrification activity of all catalysts is significantly higher than that of the comparative example. The improved pore structure of the catalyst enhances its activity stability. Comparing the catalyst effects of different ammonia introduction methods, appropriately controlling the drying time for direct ammonia introduction makes it easier to prepare catalysts with high strength and excellent performance.

[0044] Table 3 Basic Properties of Crude Oils

[0045] Table 4. Catalyst properties and catalytic effects in the examples and comparative examples

[0046] *Relative activity is based on the comparative DCT activity over 100 hours.

Claims

1. A method for preparing a hydrogenation catalyst, characterized in that: The method includes the following steps: (1) Mix aluminum hydroxide dry adhesive powder, extrusion aid and adhesive solvent; shape by kneading or rolling; and obtain aluminum oxide carrier by drying and calcination; (2) An active metal is introduced onto the alumina support prepared in step (1), and the final hydrogenation catalyst is obtained after drying and calcination. The drying process described in step (1) is carried out under an alkaline atmosphere, wherein the alkaline gas in the alkaline atmosphere is ammonia, the volume content of ammonia accounts for 2-13% of the volume fraction of the drying atmosphere, and the drying time under the alkaline atmosphere accounts for 20-100% of the total drying time; In step (1), the drying temperature is 90~160℃ and the drying time is 2~8h; In step (1), the properties of the alumina carrier are as follows: the ratio of the pore volume content of >15nm to the pore volume content of <4nm is 4.5~15.5; The hydrotreating catalyst is a heavy distillate oil hydrotreating catalyst; The aluminum hydroxide dry adhesive powder is either pure aluminum hydroxide dry powder or aluminum hydroxide dry powder containing additives, which are one or more of silicon, titanium, zinc, magnesium, boron, phosphorus, fluorine, and zirconium. The active metal component of the hydrogenation catalyst is a Group VIB or / and Group VIII metal, wherein the Group VIB metal is molybdenum and / or tungsten, and the Group VIII metal is nickel. The group VIB metal oxides and group VIII metal oxides account for 10-30 wt% and 2-10 wt% respectively, based on the weight of the hydrotreating catalyst.

2. The method according to claim 1, characterized in that: In step (1), aluminum hydroxide dry adhesive powder is first mixed with the extrusion aid, and then adhesive solvent is added.

3. The method according to claim 1, characterized in that: The volume content of ammonia in the dry atmosphere is 3-10%.

4. The method according to claim 1, characterized in that: Ammonia gas originates from the thermal decomposition of ammonia water, urea, and ammonium bicarbonate.

5. The method according to claim 1, characterized in that: In step (1), the alkaline gas is introduced at any stage of the drying process, and the drying time under the alkaline atmosphere accounts for 30-90% of the total drying time.

6. The method according to claim 1, characterized in that: In step (1), the alkaline gas is introduced at the beginning of the drying process, and the drying time under the alkaline atmosphere accounts for 35-70% of the total drying time.

7. The method according to claim 6, characterized in that: In step (1), the alkaline gas is introduced at the beginning of the drying process, and the drying time under the alkaline atmosphere accounts for 40-60% of the total drying time.

8. The method according to claim 1, characterized in that: In step (1), the roasting temperature is 500~750℃ and the roasting time is 2~7h.

9. The method according to claim 1, characterized in that: The extrusion aid is one or more of starch, polyvinyl alcohol, polyacrylamide, methylcellulose, and guar gum powder.

10. The method according to claim 1, characterized in that: The solvent for the colloid is a variety of organic acids, inorganic acids, and acids that can ionize to release H+. ＋ Compounds.

11. The method according to claim 10, characterized in that: The colloidal solvent is one or more of nitric acid, hydrochloric acid, oxalic acid, acetic acid, propionic acid, and ammonium dihydrogen phosphate.

12. The method according to claim 1, characterized in that: The properties of the alumina carrier are as follows: the ratio of the pore volume content of >15nm to the pore volume content of <4nm is 6.0~13.

5.

13. The method according to claim 1, characterized in that: The properties of the alumina carrier are as follows: the ratio of the pore volume content of >15nm to the pore volume content of <4nm is 9.0~12.

5.

14. The method according to claim 1, characterized in that: Molybdenum comes from one or more of molybdenum oxide, ammonium molybdate, and ammonium paramolybdate; tungsten comes from ammonium metatungstate; and nickel comes from one or more of nickel nitrate, nickel carbonate, basic nickel carbonate, and nickel oxalate.

15. The method according to claim 1, characterized in that: The active metal component is loaded onto the carrier by impregnation, using equal volume impregnation or excessive impregnation; stepwise impregnation or co-impregnation; the drying temperature after impregnation is 80~190℃, the drying time is 4~16h; the calcination temperature is 400~600℃, and the calcination time is 2~6h.

16. A hydrotreating catalyst prepared by the method according to any one of claims 1-15, characterized in that: The catalyst contains 10-30 wt% group VIB metal oxides and 2-10 wt% group VIII metal oxides by weight.

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