Hydrodenitrification catalyst as well as preparation method and application thereof

Abstract

The preparation method comprises the following steps: sequentially adding an AlPO4-5 phosphorus-aluminum molecular sieve of which the grain size is less than 2 microns and aluminum oxide into deionized water, carrying out ultrasonic emulsification to obtain carrier raw material slurry, carrying out suction filtration on the carrier raw material slurry, drying, and grinding to obtain carrier raw material powder, uniformly mixing the carrier raw material powder with a molding aid, and carrying out extrusion molding, drying and roasting to obtain a catalyst carrier; and (2) dissolving a metal salt containing zinc, nickel and tungsten elements in deionized water to obtain a metal impregnation liquid, impregnating the catalyst carrier by adopting an equivalent impregnation method, and curing, drying and roasting to obtain the hydrodenitrogenation catalyst. According to the preparation method, the use efficiency of the AlPO4-5 phosphorus-aluminum molecular sieve can be improved, the generation of nickel-aluminum spinel inert substances is inhibited, the active metal is promoted to form a high-activity hydrogenation active phase, the use efficiency of the active metal Ni is improved, and the hydrogenation activity of the catalyst is further improved.

Description

Technical Field

[0001] The invention relates to a hydrodenitrification catalyst and a preparation method and application thereof, and in particular to a diesel deep hydrodenitrification catalyst and a preparation method thereof. Background Art

[0002] The diesel hydrogenation process includes hydrofining, hydromodification, hydrodegassing and hydrocracking. Except for hydrofining, the latter three diesel hydrogenation processes require the use of catalysts with strong acid functions. Nitrides, especially alkaline nitrides, easily react strongly with acid-functional catalysts and poison the acid centers of acid-functional catalysts, resulting in a rapid decrease in the activity of acid-functional catalysts, making it impossible for the acid catalytic function of the catalyst to function normally, thereby affecting diesel hydrogenation, diesel hydrodegassing and diesel hydrocracking processes. Therefore, deep removal of nitrides, especially alkaline nitrides, in diesel is the key to ensuring the full performance of diesel hydrogenation, diesel hydrodegassing and diesel hydrocracking catalysts.

[0003] Nitrogen compounds in diesel can be roughly divided into two categories: one is non-heterocyclic compounds (including fatty amines, aniline and nitrile compounds); the other is heterocyclic compounds, which can be divided into basic heterocyclic compounds (pyridine, quinoline, isoquinoline, acridine, etc.) and non-basic heterocyclic compounds (pyrrole, indole and carbazole, etc.). The content of non-heterocyclic nitrogen compounds in oil products is low and easy to remove, while the content of heterocyclic nitrogen compounds, which are more difficult to remove, is high.

[0004] The general hydrodenitrogenation (HDN) process of heterocyclic nitrogen compounds mainly includes hydrogenation and CN bond hydrogenolysis reaction. The hydrogenation reaction includes two types: nitrogen heterocycle hydrogenation and aromatic ring hydrogenation. Since the aromaticity of nitrogen heterocycles is weaker than that of aromatic rings, the HDN of general nitrogen heterocyclic components must first completely hydrogenate the nitrogen-containing ring before removing the N atom. Aniline nitrogen-containing compounds also need to hydrogenate the aromatic ring before breaking the CN bond.

[0005] In summary, the hydrogenation saturation process of the aromatic ring structure in heterocyclic nitrides is the key to the denitrification of such nitrides. Since the aromatic ring structure is controlled by reaction thermodynamics and reaction kinetics during hydrogenation saturation, when the reaction pressure is fixed, the reaction temperature is increased, and the aromatic ring hydrogenation reaction rate tends to increase first and then decrease.

[0006] In order to effectively remove nitrogen compounds from diesel, many diesel hydrotreating catalyst manufacturers at home and abroad have developed diesel hydrotreating refining catalysts with good denitrification activity, which can effectively remove nitrogen compounds while achieving ultra-deep desulfurization.

[0007] Chinese patent CN1778874A discloses a hydrogenation and dearomatization catalyst containing AlPO4-5 phosphorus aluminum molecular sieve, which optimizes the pore structure and surface acidity of the catalyst carrier by utilizing the adjustable acidity and concentrated pore distribution characteristics of AlPO4-5 phosphorus aluminum molecular sieve, improves the dispersion of the metal active phase, promotes the active metal to form a highly active hydrogenation active phase to improve the hydrogenation activity of the catalyst, and improves the hydrogenation saturation efficiency of the catalyst for aromatics in diesel. However, the carrier and the active metals Ni and W easily interact to form inert substances such as nickel-aluminum spinel, which reduces the use efficiency of the active metal Ni, thereby affecting and reducing the hydrogenation activity of the catalyst.

[0008] Chinese patent CN102485332A discloses a molecular sieve-containing distillate oil hydrodeacidification catalyst and a preparation method thereof, wherein the catalyst is prepared with magnesium oxide, aluminum oxide, AlPO4-5 aluminum phosphorus molecular sieve, and ZSM-5 molecular sieve as carrier materials, and Ni or Co and W or Mo as active components to form a catalyst with high hydrodeacidification activity, and the catalyst also has hydrodesulfurization and hydrodenitrogenation activities. However, in the preparation process of the catalyst carrier, the powder material is mixed by mechanical mixing, and is dried and calcined twice, and the overall preparation process of the carrier is time-consuming and energy-intensive.

[0009] Diesel hydrorefining usually adopts a fixed bed hydrogenation reactor, and the catalyst used is clover or cylindrical. In the catalyst preparation process, the alumina powder, molecular sieve powder material and molding aid (Tianqing powder, citric acid and nitric acid aqueous solution) required for the preparation of the carrier are first mechanically mixed, and then prepared into a strip carrier using an extrusion molding device. After drying and roasting, it is impregnated with an active metal aqueous solution, and the catalyst is obtained after drying and roasting. In the process of preparing the catalyst carrier, a simple mechanical mixing method is used to mix the alumina powder and the molecular sieve powder, and there is a problem of insufficient and uneven mixing of the alumina powder and the molecular sieve powder. In the process of preparing the catalyst, because a strong force is easily generated between the catalyst metal component and the carrier, it is difficult for the active metal to form a highly active hydrogenation active phase, and the catalyst hydrogenation activity cannot be fully exerted. Summary of the invention

[0010] The purpose of the present invention is to develop a deep hydrodenitrification catalyst for use in a deep hydrorefining process of diesel. Under the condition that the reaction pressure is not more than 8MPa, the denitrification activity of the catalyst is fully exerted to reduce the nitrogen in the diesel to below 20μg / g, and a low-nitrogen raw material is provided for catalysts that are prone to nitrogen poisoning, such as diesel hydroreforming, diesel hydrodecondensation and diesel hydrocracking, so as to ensure that the activity of the diesel hydroreforming, diesel hydrodecondensation and diesel hydrocracking catalysts is fully exerted and the catalysts run smoothly over a long period of time.

[0011] To achieve the above object, the present invention provides a method for preparing a hydrodenitrogenation catalyst, the preparation method comprising the following steps:

[0012] (1) adding AlPO4-5 aluminum phosphorus molecular sieve with a grain size of less than 2 μm and alumina to deionized water, obtaining a carrier raw material slurry by ultrasonic emulsification, filtering, drying, and grinding the carrier raw material slurry to obtain a carrier raw material powder, mixing the carrier raw material powder with a molding aid, extruding, drying, and calcining to obtain a catalyst carrier;

[0013] (2) A metal salt containing zinc, nickel and tungsten elements is dissolved in deionized water to obtain a metal impregnation solution, and the catalyst carrier is impregnated with the metal impregnation solution by an equal amount impregnation method. After curing, drying and calcining, a hydrodenitrogenation catalyst is obtained.

[0014] In the preparation method of the hydrodenitrogenation catalyst of the present invention, in step (1), the addition amount of the AlPO4-5 aluminum phosphorus molecular sieve is 2 to 40 wt% of the weight of the aluminum oxide.

[0015] The preparation method of the hydrodenitrogenation catalyst of the present invention, in step (2), in the hydrodenitrogenation catalyst, each metal is calculated as its oxide, the ZnO content is 1-10wt% of the catalyst weight, the NiO content is 1-10wt% of the catalyst weight, and the WO3 content is 10-30wt% of the catalyst weight.

[0016] The method for preparing the hydrodenitrogenation catalyst of the present invention preferably comprises the following: in the hydrodenitrogenation catalyst, the ZnO content is 2-10wt% of the catalyst weight, the NiO content is 2-10wt% of the catalyst weight, and the WO3 content is 15-30wt% of the catalyst weight.

[0017] The method for preparing the hydrodenitrogenation catalyst of the present invention, wherein the specific surface area of ​​the alumina is 340 to 400 m 2 / g, and the pore volume is 0.90~1.20mL / g.

[0018] The preparation method of the hydrodenitrogenation catalyst of the present invention, the specific surface area of ​​the AlPO4-5 phosphorus aluminum molecular sieve is 290 to 300 m 2 / g, and the pore volume is 0.24~0.26mL / g.

[0019] In the method for preparing the hydrodenitrogenation catalyst of the present invention, the metal salt containing zinc comprises at least one of zinc nitrate hexahydrate, zinc acetate and zinc sulfate.

[0020] The method for preparing the hydrodenitrogenation catalyst of the present invention comprises the metal salt containing nickel comprising at least one of nickel nitrate hexahydrate, nickel acetate and nickel sulfate.

[0021] In the method for preparing the hydrodenitrogenation catalyst of the present invention, the metal salt containing tungsten comprises at least one of ammonium metatungstate, tungstic acid and metatungstic acid.

[0022] In the method for preparing the hydrodenitrogenation catalyst of the present invention, the ultrasonic frequency of the ultrasonic emulsification is 20000 Hz, and the emulsification time is 0.5 to 2 hours.

[0023] The preparation method of the hydrodenitrogenation catalyst of the present invention, the shape of the catalyst carrier is one of flake, toothed ball, Raschig ring, cylindrical bar, clover and four-leaf clover, preferably cylindrical bar, clover and four-leaf clover.

[0024] The method for preparing a hydrodenitrogenation catalyst of the present invention, wherein the diameter of the hydrodenitrogenation catalyst is a thin strip of 0.8 mm to 2.0 mm or a thick strip of >2.5 mm, preferably a thin strip of 1.2 mm to 1.6 mm.

[0025] In the preparation method of the hydrodenitrogenation catalyst of the present invention, in step (2), the drying temperature is 100-140° C., and the drying time is 2-5 hours; the calcination temperature is 400-500° C., and the calcination time is 3-6 hours.

[0026] In the preparation method of the hydrodenitrogenation catalyst of the present invention, in step (1), the molding aid comprises at least one of sesbania powder, nitric acid and citric acid, and the addition amount of each molding aid is 3% of the weight of alumina.

[0027] The present invention also provides a hydrodenitrogenation catalyst, which is obtained by the above preparation method.

[0028] The invention also provides an application of a hydrodenitrogenation catalyst, wherein the hydrodenitrogenation catalyst is used for the hydrodenitrogenation reaction of diesel.

[0029] In the application of the hydrodenitrogenation catalyst of the present invention, the diesel comprises at least one of straight-run diesel, catalytic diesel and coking diesel.

[0030] The application of the hydrodenitrogenation catalyst of the present invention is that the reaction temperature of the hydrodenitrogenation reaction is 320-390°C, the reaction pressure is 4-7MPa, and the space velocity is 1.0-2.0h -1 , the hydrogen-to-oil ratio is 200-500:1; the nitrogen content of the hydrogenated diesel obtained by the hydrodenitrogenation reaction is less than 20 μg / g.

[0031] The preparation method of the hydrodenitrogenation catalyst of the present invention adopts AlPO4-5 phosphorus aluminum molecular sieve with a grain size of less than 2 μm. Compared with AlPO4-5 phosphorus aluminum molecular sieve with a larger grain size, the grain size of the present invention less than 2 μm can increase the catalytic activity of the AlPO4-5 phosphorus aluminum molecular sieve. The present invention adopts ultrasonic emulsification to make the mixing of AlPO4-5 phosphorus aluminum molecular sieve and alumina more complete, improve the uniformity of material mixing, and thus improve the use efficiency of the AlPO4-5 phosphorus aluminum molecular sieve.

[0032] The preparation method of the hydrodenitrogenation catalyst of the present invention introduces zinc into the metal impregnation solution. Zinc and other active metals compete for adsorption on the surface of the catalyst carrier to form a zinc-aluminum spinel structure, adjust the interaction between Ni, W and the carrier, inhibit the formation of inert substances such as nickel-aluminum spinel, promote the active metal to form a highly active hydrogenation active phase, improve the use efficiency of the active metal Ni, and further improve the hydrodenitrogenation activity of the catalyst. The hydrodenitrogenation catalyst obtained by the preparation method of the present invention is evaluated by hydrogenation of different raw materials, and the process conditions of the deep hydrodenitrogenation reaction process of different raw materials are optimized. The hydrodenitrogenation catalyst is suitable for the hydrodenitrogenation process of diesel fractions in the field of petroleum refining, and can produce low-nitrogen diesel with a nitrogen content of less than 20μg / g. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The XRD spectrum of the AlPO4-5 aluminum phosphorus molecular sieve used in the present invention. DETAILED DESCRIPTION

[0034] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be construed as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention. The raw materials used in the following examples and comparative examples, unless otherwise specified, are all commercially available.

[0035] Raw materials and sources:

[0036] Alumina powder was purchased from Shandong Yuneng Catalyst Technology Co., Ltd. with a specific surface area of ​​360m 2 / g, pore volume 0.92mL / g;

[0037] The AlPO4-5 aluminum phosphorus molecular sieve is made in the laboratory, with a grain size of less than 2 μm and a specific surface area of ​​290 m 2 / g, pore volume is 0.24mL / g;

[0038] Zinc nitrate hexahydrate was purchased from Hubei Changxinsheng Chemical Co., Ltd. with a purity of 99 wt%; zinc acetate was purchased from Tianjin Komiou Chemical Reagent Co., Ltd. with a purity of 99 wt%;

[0039] Nickel nitrate hexahydrate was purchased from Xinxiang Chuangjia New Materials Co., Ltd. with a purity of 99 wt%;

[0040] Ammonium metatungstate was purchased from Henan Detai Chemical Products Co., Ltd. with a purity of 99 wt%;

[0041] Preparation Example 1:

[0042] Take 2kg of deionized water and add it to a 5L stainless steel barrel, take 800g of alumina powder, 16g of AlPO4-5 phosphorus aluminum molecular sieve with a grain size of less than 2μm and add them to the deionized water in sequence under stirring for slurrying, transfer the slurry to an ultrasonic emulsifier after slurrying for 10 minutes, emulsify at a frequency of 20000Hz for 30 minutes, filter, dry, grind through a 180-mesh sieve to obtain a carrier raw material powder. Take 500g of the carrier raw material powder, add 15g of sesbania powder thereto, mix evenly, drop a mixed solution consisting of 15g of nitric acid (68wt%), 15g of citric acid and 400g of deionized water to mix, extrude into 1.5mm clover-shaped strips, dry at 120℃ for 2h, and then roast at 550℃ for 4h to prepare a No. 1 carrier.

[0043] Preparation Example 2:

[0044] Take 2kg of deionized water and add it to a 5L stainless steel barrel, take 800g of alumina powder, 32g of AlPO4-5 phosphorus aluminum molecular sieve with a grain size of less than 2μm and add them to the deionized water in sequence under stirring for slurrying, transfer the slurry to an ultrasonic emulsifier after slurrying for 10 minutes, emulsify at a frequency of 20000Hz for 30 minutes, filter, dry, grind through a 180-mesh sieve to obtain a carrier raw material powder. Take 500g of the carrier raw material powder, add 15g of sesbania powder thereto, mix evenly, drop a mixed solution consisting of 15g of nitric acid (68wt%), 15g of citric acid and 400g of deionized water to mix, extrude into 1.5mm clover-shaped strips, dry at 120℃ for 2h, and then roast at 550℃ for 4h to prepare a 2# carrier.

[0045] Preparation Example 3:

[0046] Take 2kg of deionized water and add it to a 5L stainless steel barrel, take 800g of alumina powder, 80g of AlPO4-5 phosphorus aluminum molecular sieve with a grain size of less than 2μm and add them to the deionized water in sequence under stirring for slurrying, transfer the slurry to an ultrasonic emulsifier after slurrying for 10 minutes, emulsify at a frequency of 20000Hz for 30 minutes, filter, dry, grind through a 180-mesh sieve to obtain a carrier raw material powder. Take 500g of the carrier raw material powder, add 15g of sesbania powder thereto, mix evenly, drop a mixed solution consisting of 15g of nitric acid (68wt%), 15g of citric acid and 400g of deionized water for kneading, extrude into 1.5mm clover-shaped strips, dry at 120℃ for 2h, and then roast at 550℃ for 4h to make a 3# carrier.

[0047] Preparation Example 4:

[0048] Take 2kg of deionized water and add it to a 5L stainless steel barrel, take 800g of alumina powder, 160g of AlPO4-5 phosphorus aluminum molecular sieve with a grain size of less than 2μm and add them to the deionized water in sequence under stirring for slurrying, transfer the slurry to an ultrasonic emulsifier after slurrying for 10 minutes, emulsify at a frequency of 20000Hz for 30 minutes, filter, dry, grind through a 180-mesh sieve to obtain a carrier raw material powder. Take 500g of the carrier raw material powder, add 15g of sesbania powder thereto, mix evenly, drop a mixed solution consisting of 15g of nitric acid (68wt%), 15g of citric acid and 400g of deionized water to mix, extrude into 1.5mm clover-shaped strips, dry at 120℃ for 2h, and then roast at 550℃ for 4h to make a 4# carrier.

[0049] Preparation Example 5:

[0050] Take 2kg of deionized water and add it to a 5L stainless steel barrel, take 800g of alumina powder, 320g of AlPO4-5 phosphorus aluminum molecular sieve with a grain size of less than 2μm, add them to the deionized water in sequence under stirring for slurrying, transfer the slurry to an ultrasonic emulsifier after slurrying for 10 minutes, emulsify at a frequency of 20000Hz for 30 minutes, filter, dry, grind through a 180-mesh sieve to obtain a carrier raw material powder. Take 500g of the carrier raw material powder, add 15g of sesbania powder thereto, mix evenly, drop a mixed solution consisting of 15g of nitric acid (68wt%), 15g of citric acid and 400g of deionized water for kneading, extrude into 1.5mm clover-shaped strips, dry at 120℃ for 2h, and then roast at 550℃ for 4h to make a 5# carrier.

[0051] Preparation Comparative Example 1:

[0052] The difference from Preparation Example 4 is that no AlPO4-5 aluminum phosphorus molecular sieve is added.

[0053] Take 500g of alumina powder and 15g of sesbania powder, mix them evenly, add a mixed solution consisting of 15g of nitric acid (68wt%), 15g of citric acid and 400g of deionized water, knead them, extrude them into 1.5mm clover-shaped strips, dry them at 120℃ for 2h, and then calcine them at 550℃ for 4h to make D1# carrier.

[0054] Preparation Comparative Example 2:

[0055] The difference from Preparation Example 4 is that AlPO4-5 aluminum phosphorus molecular sieve with a grain size of 10 μm is added.

[0056] Take 2kg of deionized water and add it to a 5L stainless steel barrel, take 800g of alumina powder and 160g of AlPO4-5 phosphorus aluminum molecular sieve with a grain size of 10μm and add them to the deionized water in sequence under stirring for slurrying. After slurrying for 10 minutes, transfer the slurry to an ultrasonic emulsifier and emulsify it at a frequency of 20000Hz for 30 minutes. The slurry is filtered, dried, and ground through a 180-mesh sieve to obtain a carrier raw material powder. Take 500g of the carrier raw material powder, add 15g of sesbania powder to it, mix well, drop a mixed solution consisting of 15g of nitric acid (68wt%), 15g of citric acid and 400g of deionized water to mix and knead, extrude into 1.5mm clover-shaped strips, dry at 120℃ for 2h, and then roast at 550℃ for 4h to prepare D2# carrier.

[0057] Evaluation Example 1:

[0058] Take 10g or more of 1#-5# carriers and D1#-D2# carriers respectively, and use the equal amount impregnation method to impregnate the carriers in the Ni-W-Zn impregnation solution, then dry at 120°C for 3h, and then calcine at 450°C for 4h to prepare 1#-5# catalysts and D1#-D2# catalysts. The NiO content in the catalyst is 5wt% of the catalyst weight, the WO3 content is 20wt% of the catalyst weight, and the ZnO content is 1wt% of the catalyst weight.

[0059] A quinoline / decahydronaphthalene solution with a nitrogen content of 500 μg / g was used as a model compound for the hydrodenitrogenation reaction. The reaction pressure was 3 MPa, the reaction temperature was 330 °C, and the space velocity was 2.0 h -1 Under the conditions of 500: hydrogen-to-oil ratio, the denitrification activities of 1#-5# catalysts and D1#-D2# catalysts were investigated respectively. The test results are shown in Table 1.

[0060] Table 1 Hydrogenation and denitrification effects of catalysts 1#-5# and D1#-D2# on model compounds

[0061]

[0062] From the model compound hydrogenation evaluation results in Table 1, it can be seen that the denitrification effects of the catalysts D1#-D2# are poor due to the fact that the catalysts do not add AlPO4-5 phosphorus aluminum molecular sieve or add AlPO4-5 phosphorus aluminum molecular sieve with a grain size greater than 2μm. The catalytic activity of the catalyst 4# is increased due to the use of the AlPO4-5 phosphorus aluminum molecular sieve with a grain size less than 2μm of the present invention, thereby improving the hydrogenation denitrification effect of the catalyst.

[0063] Embodiment 1-7:

[0064] The 4# carrier was impregnated with Ni-W-Zn impregnation solution by equal amount impregnation method to prepare catalysts with different NiO, WO3 and ZnO contents. The carrier impregnated with Ni-W-Zn metal solution was dried at 120℃ for 3h, and then calcined at 450℃ for 4h to prepare 6#-12# catalysts. A quinoline / decahydronaphthalene solution with a nitrogen content of 500μg / g was used as a model compound for the hydrodenitrogenation reaction. The reaction pressure was 3MPa, the reaction temperature was 330℃, and the space velocity was 2.0h. -1 Under the conditions of 500 hydrogen-to-oil ratio, the denitrification activity of catalysts 6#-12# was investigated respectively. The corresponding catalyst metal content and denitrification activity are shown in Table 2.

[0065] Comparative Example 1:

[0066] The difference from Example 1-3 is that no Zn is added to the impregnation solution.

[0067] The 4# carrier was impregnated with Ni-W impregnation solution by equal amount impregnation method to prepare catalysts with different NiO and WO3 contents. The carrier impregnated with Ni-W metal solution was dried at 120℃ for 3h, and then calcined at 450℃ for 4h to prepare D3# catalyst. A quinoline / decahydronaphthalene solution with a nitrogen content of 500μg / g was used as a model compound for the hydrodenitrogenation reaction. The reaction pressure was 3MPa, the reaction temperature was 330℃, and the space velocity was 2.0h. -1 Under the conditions of 500 hydrogen-to-oil ratio, the denitrification activity of D3# catalyst was investigated. The corresponding catalyst metal content and denitrification activity are shown in Table 2.

[0068] Comparative Example 2:

[0069] The difference from Example 4-6 is that no Zn is added to the impregnation solution.

[0070] The 4# carrier was impregnated with Ni-W impregnation solution by equal amount impregnation method to prepare catalysts with different NiO and WO3 contents. The carrier impregnated with Ni-W metal solution was dried at 120℃ for 3h, and then calcined at 450℃ for 4h to prepare D4# catalyst. A quinoline / decahydronaphthalene solution with a nitrogen content of 500μg / g was used as a model compound for the hydrodenitrogenation reaction. The reaction pressure was 3MPa, the reaction temperature was 330℃, and the space velocity was 2.0h. -1 Under the conditions of 500 hydrogen-to-oil ratio, the denitrification activity of D4# catalyst was investigated. The corresponding catalyst metal content and denitrification activity are shown in Table 2.

[0071] Comparative Example 3:

[0072] The difference from Example 7 is that Zn is not added to the impregnation solution.

[0073] The 4# carrier was impregnated with Ni-W impregnation solution by equal amount impregnation method to prepare catalysts with different NiO and WO3 contents. The carrier impregnated with Ni-W metal solution was dried at 120℃ for 3h, and then calcined at 450℃ for 4h to prepare D5# catalyst. A quinoline / decahydronaphthalene solution with a nitrogen content of 500μg / g was used as a model compound for the hydrodenitrogenation reaction. The reaction pressure was 3MPa, the reaction temperature was 330℃, and the space velocity was 2.0h. -1 Under the conditions of 500 hydrogen-to-oil ratio, the denitrification activity of D5# catalyst was investigated. The corresponding catalyst metal content and denitrification activity are shown in Table 2.

[0074] Table 2 Denitrification rate evaluated by metal content and model compound of catalysts 6#-12# and D3#-D5#

[0075]

[0076] It can be seen from the results in Table 2 that compared with the catalyst without Zn addition, the catalyst with Zn added in the present invention has a higher denitrification rate. This is because zinc and Ni, W compete for adsorption on the surface of the catalyst carrier to form a zinc-aluminum spinel structure, which adjusts the interaction between Ni, W and the carrier, inhibits the formation of inert substances such as nickel-aluminum spinel, promotes the active metal to form a highly active hydrogenation active phase, improves the use efficiency of the active metal Ni, and thus improves the hydrogenation denitrification activity of the catalyst.

[0077] Embodiment 8:

[0078] Using 10# catalyst and D4# catalyst, with straight-run diesel, catalytic cracking diesel, coking diesel or mixed oil of the above diesel fractions from a refinery as raw materials, the hydrodenitrogenation effect of the catalyst on various diesel fractions under different process conditions was investigated. The results are shown in Table 3.

[0079] Table 3 Hydrogenation and denitrogenation effects of catalysts on different raw materials under different conditions

[0080]

[0081]

[0082] It can be seen from the results in Table 3 that, under different catalytic conditions, compared with the catalyst without Zn addition, the catalyst with Zn added in the present invention has a higher denitrification rate, which confirms that zinc and Ni, W compete for adsorption on the surface of the catalyst carrier to form a zinc-aluminum spinel structure, adjusts the interaction between Ni, W and the carrier, inhibits the formation of inert substances such as nickel-aluminum spinel, promotes the active metal to form a highly active hydrogenation active phase, improves the utilization efficiency of the active metal Ni, and thereby improves the hydrogenation denitrification activity of the catalyst.

[0083] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a hydrodenitrogenation catalyst, characterized in that: The following steps are involved: (1) adding AlPO4-5 aluminum phosphorus molecular sieve with a grain size of less than 2 μm and alumina to deionized water, obtaining a carrier raw material slurry by ultrasonic emulsification, filtering, drying, and grinding the carrier raw material slurry to obtain a carrier raw material powder, mixing the carrier raw material powder with a molding aid, extruding, drying, and calcining to obtain a catalyst carrier; (2) A metal salt containing zinc, nickel and tungsten elements is dissolved in deionized water to obtain a metal impregnation solution, and the catalyst carrier is impregnated with the metal impregnation solution by an equal amount impregnation method. After curing, drying and calcining, a hydrodenitrogenation catalyst is obtained.

2. The preparation method according to claim 1, characterized in that: In step (1), the addition amount of the AlPO4-5 aluminum phosphorus molecular sieve is 2 to 40 wt% of the weight of alumina.

3. The preparation method according to claim 1, characterized in that: In step (2), in the hydrodenitrogenation catalyst, the content of each metal in terms of its oxide is 1-10 wt % of the weight of the catalyst, the content of NiO is 1-10 wt % of the weight of the catalyst, and the content of WO3 is 10-30 wt % of the weight of the catalyst.

4. The preparation method according to claim 3, characterized in that: In the hydrodenitrogenation catalyst, the content of ZnO is 2-10 wt% of the weight of the catalyst, the content of NiO is 2-10 wt% of the weight of the catalyst, and the content of WO3 is 15-30 wt% of the weight of the catalyst.

5. The preparation method according to claim 1, characterized in that: The specific surface area of ​​the alumina is 340 to 400 m 2 / g, and the pore volume is 0.90~1.20mL / g.

6. The preparation method according to claim 1, characterized in that: The specific surface area of ​​the AlPO4-5 aluminum phosphorus molecular sieve is 290 to 300 m 2 / g, and the pore volume is 0.24~0.26mL / g.

7. The preparation method according to claim 1, characterized in that: The metal salt containing zinc includes at least one of zinc nitrate hexahydrate, zinc acetate, and zinc sulfate; The nickel-containing metal salt includes at least one of nickel nitrate hexahydrate, nickel acetate, and nickel sulfate; The metal salt containing tungsten includes at least one of ammonium metatungstate, tungstic acid, and metatungstic acid; The diameter of the hydrodenitrogenation catalyst is a thin strip of 0.8 mm to 2.0 mm or a thick strip of >2.5 mm.

8. A hydrodenitrogenation catalyst, characterized in that The hydrodenitrogenation catalyst is obtained by the preparation method according to any one of claims 1 to 7.

9. An application of a hydrodenitrogenation catalyst, characterized in that: The hydrodenitrogenation catalyst obtained by the preparation method according to any one of claims 1 to 7 is used for the hydrodenitrogenation reaction of diesel.

10. The use according to claim 9, characterized in that: The diesel comprises at least one of straight-run diesel, catalytic diesel and coking diesel.

11. The use according to claim 9, characterized in that: The reaction temperature of the hydrodenitrogenation reaction is 320-390°C, the reaction pressure is 4-7MPa, and the space velocity is 1.0-2.0h -1 , the hydrogen-to-oil ratio is 200-500:1; the nitrogen content of the hydrogenated diesel obtained by the hydrodenitrogenation reaction is less than 20 μg / g.

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