A catalyst for deep removal of aromatic hydrocarbons and a preparation method and application thereof

Abstract

The application provides a catalyst for deep removal of aromatic hydrocarbons and a preparation method and application thereof. The catalyst for deep removal of aromatic hydrocarbons is obtained by impregnating a gamma-Al2O3 carrier or a gamma-Al2O3 carrier modified by an additive in an active metal impregnation solution, and then drying and calcining. The active metal impregnation solution contains urea, C1-C8 alcohols and amino acids. In the catalyst for deep removal of aromatic hydrocarbons, the active metal is distributed on the surface of the carrier and in the pores of the carrier, and the active metal on the surface of the carrier forms a stacking structure. The active metal includes Ni and W. In the preparation process of the active metal impregnation solution, proper proportions of urea, C1-C8 alcohols and amino acids and other substances are added, so that the aromatic saturation capacity and the desulfurization and denitrification performance of the prepared catalyst can be significantly improved.

Description

Technical Field

[0001] This invention relates to a catalyst for deep removal of aromatics, its preparation method and application, belonging to the field of catalytic dearomatization technology. Background Technology

[0002] With the accelerating trend of crude oil deterioration and increasing weight, the aromatic content of feedstock oils is continuously rising during the hydrorefining process of jet fuel and diesel. Aromatics in petroleum fractions mainly include the following four categories:

[0003] (1) Monocyclic aromatic hydrocarbons, including benzene and alkylbenzenes, benzocycloalkanes, etc.;

[0004] (2) Bicyclic aromatic hydrocarbons, including naphthalene and alkylnaphthalene, biphenyl and naphthocycloalkanes, etc.;

[0005] (3) Tricyclic aromatic hydrocarbons, including anthracene, phenanthrene and fluorene and their alkyl derivatives, etc.;

[0006] (4) Polycyclic aromatic hydrocarbons, such as pyrene and fluoranthene.

[0007] The aromatic nuclei in aromatic hydrocarbons are very stable and difficult to break directly through ring-opening. Larger fused-ring and polycyclic aromatic hydrocarbons can only undergo ring-opening and further cracking reactions after the aromatic ring has been hydrogenated to saturation. Studies have shown that the hydrogenation reactions of aromatic hydrocarbons follow the following rules:

[0008] ①The equilibrium constant of the aromatic hydrogenation reaction decreases as the reaction temperature increases;

[0009] ② In the 600K-700K range, the equilibrium constant lgKp value of the complete hydrogenation saturation reaction of aromatics decreases as the number of rings in the molecule increases;

[0010] ③ In the 600K-700K range, the equilibrium constant of the first ring hydrogenation saturation reaction in polycyclic aromatic hydrocarbons is the largest, while the equilibrium constants of the second and third ring saturation reactions decrease successively.

[0011] ④ When the temperature exceeds 600K, the equilibrium constant of the saturated hydrogenation reaction of aromatics is relatively small. Therefore, higher pressure is required to improve the equilibrium conversion rate.

[0012] ⑤ Hydrogenation saturation of the first aromatic ring in a fused-ring aromatic hydrocarbon is relatively easy, with a relative reaction rate constant of 1.38, which is 10 times that of benzene hydrogenation. However, hydrogenation saturation of the last remaining aromatic ring is more difficult, and its reaction rate is close to that of benzene.

[0013] The aromatic hydrocarbon content is directly related to the smoke point of jet fuel. For example, the specifications for No. 3 jet fuel require an aromatic hydrocarbon volume content of no more than 20.0% and a smoke point of no less than 25.0 mm. Straight-run kerosene fractions mainly contain monocyclic and bicyclic aromatic hydrocarbons, and essentially no tricyclic or higher aromatic hydrocarbons. Monocyclic aromatic hydrocarbons mainly include alkylbenzenes, indene, tetrahydronaphthalene, and indene derivatives, while bicyclic aromatic hydrocarbons mainly include naphthalene and naphthalene derivatives. Hydrogenation removal of monocyclic and bicyclic aromatic hydrocarbons is more difficult than that of multicyclic aromatic hydrocarbons. Therefore, developing catalysts with higher aromatic hydrocarbon removal activity is of great significance for producing No. 3 jet fuel from low-smoke-point kerosene.

[0014] In industry, aromatic saturated catalysts for distillate oils mainly include two types: supported metal sulfide catalysts and supported noble metal catalysts. When the sulfur and nitrogen content in the feed oil is high, γ-Al₂O₃-supported sulfide NiMo, NiW, and CoMo catalysts are typically used. When the sulfur and nitrogen content in the feed oil is sufficiently low, highly active supported noble metal catalysts are more effective.

[0015] The advantage of supported metal sulfide catalysts is that they are not affected by poisoning in the feedstock; their disadvantage is that they have low hydrogenation activity and the reaction rate is very slow under normal hydrogenation conditions. To achieve a high degree of aromatic removal, harsh reaction conditions are usually required (such as a temperature of 360-425℃), while at high temperatures, thermodynamic equilibrium limits the degree of aromatic hydrogenation.

[0016] Supported noble metal catalysts are mainly used in two-stage processes involving desulfurization and aromatic removal. The first stage uses a traditional sulfide catalyst, which reduces the sulfur content through harsh hydrogenation treatment. The second stage uses a noble metal catalyst for aromatic saturation. Its advantages include deep aromatic removal under relatively mild reaction conditions (150-350℃). Its disadvantages include the second-stage catalyst being highly sensitive to sulfides in the feedstock, requiring the sulfur content in the product to be reduced to the ppm level after the first-stage refining process.

[0017] Currently, the most studied aromatic hydrocarbon removal catalysts mainly fall into the following three categories:

[0018] (1) Non-precious metal sulfide catalysts. The advantage of this type of catalyst is that it is not sensitive to the poisoning effect of sulfide species in the raw materials and has strong adaptability. It is also the most widely used in industry at present, but it generally has the problem of low hydrogenation activity.

[0019] (2) Noble metal catalysts: These catalysts have high hydrogenation activity and can achieve deep saturation of aromatics under relatively mild conditions. However, when the feedstock contains high levels of sulfides, the catalyst is easily poisoned and deactivated, and the production cost is high.

[0020] (3) Other types of catalysts, mainly including amorphous alloy catalysts, transition metal carbon or nitride catalysts, etc., but these catalysts have harsh preparation conditions, poor stability, and high production costs, which limit their large-scale application.

[0021] Below are some existing technologies related to this invention, such as Chinese patent CN101099934A, which discloses a metal nitride catalyst for saturated hydrogenation of aromatics. This catalyst involves supporting a nickel-molybdenum bimetallic nitride on alumina, stirring and impregnating at room temperature for 2-4 hours, filtering, thoroughly drying, vacuum drying at 60-100℃ for 5-8 hours, pressing into tablets, sieving, and directly calcining. The calcination process involves raising the temperature from room temperature to 650-680℃ at a rate of 10℃ / min in an Ar gas flow, maintaining this temperature for 2 hours, with an Ar gas space velocity of 500-1500 h⁻¹. -1 Switch to H2 airflow and maintain for 2 hours, then cool to room temperature in H2 at an H2 space velocity of 500-1500 h⁻¹. -1 Finally, after passivation in N2 containing 1% O2 for 4 hours, the catalyst was used for the saturated hydrogenation of monocyclic and bicyclic aromatic hydrocarbons, exhibiting high catalytic activity.

[0022] The drawbacks of this technology, or the shortcomings of this invention, are that the calcination process for preparing the catalyst is cumbersome, has high production costs, and is not economical.

[0023] Chinese patent CN105521797A discloses a supported bimetallic catalyst and its preparation method, which includes impregnating a support with a compound containing a first active metal component and a compound containing a second active metal component, reducing and activating the support, and impregnating the reduced and activated product with a solution containing the second active metal component in a reducing or inert atmosphere. The prepared catalyst has significantly higher aromatic saturation activity.

[0024] The drawback of this technology, or the deficiency of this invention, is that the catalyst prepared by this method requires the use of precious metals, resulting in high economic costs.

[0025] Chinese patent CN106582707A discloses a supported alloy-type aromatic saturated catalyst and its preparation method, which mainly solves the problem of low hydrogenation saturation of polycyclic aromatic hydrocarbons in the prior art. The supported alloy-type aromatic saturated catalyst uses at least one selected from alumina, silicon oxide, titanium oxide or amorphous silicon aluminum as a support, and uses an alloy formed by noble metals and non-noble metals as the active component, which has the characteristics of high hydrogenation saturation activity.

[0026] The drawback of this technology, or the deficiency of this invention, is that the catalyst prepared by this method requires the use of precious metals, resulting in high economic costs.

[0027] US Patent 5308814A discloses a noble metal dearomatic catalyst, which uses Y zeolite and high-temperature resistant inorganic oxides (such as silica, alumina, or silica and alumina) to prepare a support, and loads platinum and palladium on the obtained support, wherein the proportion of Y zeolite in the support is 10-90%.

[0028] The drawbacks of this technology, or its shortcomings relative to the present invention, are: the use of precious metals and molecular sieves results in high production costs.

[0029] In addition, the typical support materials for commonly used hydrogenation catalysts are generally Al2O3 or modified Al2O3, and the active metal components are usually supported W-Ni, Co-Mo, Mo-Ni, Co-Mo-Ni, W-Mo-Ni, etc. During the preparation of the support, the active metals W, Ni, Co, and Mo are prone to forming strong MO-Al bonds with the Al2O3 support, which is the so-called "support effect". This causes the active component of the catalyst to form spinel and lose its activity, or makes it difficult for the active component to sulfide, thus reducing the catalyst activity.

[0030] Therefore, providing a novel, highly active, supported catalyst with non-precious metals as the active metal component for the deep removal of aromatics, as well as its preparation method and application, has become an urgent technical problem to be solved in this field. Summary of the Invention

[0031] To address the aforementioned shortcomings and deficiencies, an object of the present invention is to provide a catalyst for the deep removal of aromatics. The catalyst provided by the present invention is a supported, non-precious metal-based hydrotreating catalyst with high aromatic removal activity for the deep removal of aromatics.

[0032] Another object of the present invention is to provide a method for preparing the catalyst for deep removal of aromatics as described above.

[0033] Another object of the present invention is to provide the application of the catalyst described above for deep removal of aromatics in the deep removal of aromatics from distillate oils.

[0034] To achieve the above objectives, on the one hand, the present invention provides a catalyst for deep removal of aromatics, wherein the catalyst for deep removal of aromatics is obtained by first impregnating a γ-Al2O3 support or an additive-modified γ-Al2O3 support in an active metal impregnation solution, and then drying and calcining it.

[0035] The active metal impregnation solution contains urea, C1-C8 alcohols, and amino acids.

[0036] In the catalyst for deep removal of aromatics, the active metal is distributed on the surface of the support and in the pores of the support, and the active metal forms a stacked structure on the surface of the support.

[0037] The active metals include Ni and W.

[0038] In one specific embodiment of the catalyst described above in this invention, the mass ratio of urea, C1-C8 alcohols, and amino acids in the active metal impregnation solution is 45-88:18-44:26-47.

[0039] The preferred ratio is 50-85:20-42:28-45.

[0040] In this invention, when the mass ratio of urea, C1-C8 alcohols and amino acids contained in the active metal impregnation solution is not within the above-mentioned limits, the prepared active metal impregnation solution is unstable and cannot be used to prepare a catalyst for deep removal of aromatics.

[0041] The present invention does not have any special requirements for the ratio of urea, C1-C8 alcohols, amino acids to γ-Al2O3 carrier or γ-Al2O3 carrier modified with additives in the active metal impregnation solution, or the ratio of urea, C1-C8 alcohols, amino acids to Ni precursor and W precursor, etc., and can be reasonably adjusted as needed.

[0042] As a specific embodiment of the catalyst described above in this invention, the C1-C8 alcohols include one or a combination of several of methanol, ethanol, ethylene glycol, propanol, glycerol, butanol, butanediol, pentanol, hexanol, octanol, and methylcyclohexanol.

[0043] Butylene glycol is preferred.

[0044] The C1-C8 alcohols used in this invention have good water solubility, which can reduce the surface tension of aqueous solutions, promote the migration of active metals in the carrier channels, and make full use of the carrier surface.

[0045] In one specific embodiment of the catalyst described above in this invention, the amino acid includes one or a combination of several of the following: glycine, alanine, leucine, isoleucine, methionine, phenylalanine, glutamine, threonine, glutamic acid, and lysine.

[0046] Alanine is preferred.

[0047] The amino acids used in this invention have both W-loving carboxyl groups and Ni-loving amino groups, which can complex active metals to form complexes. This can promote the appropriate aggregation of active metals on the support surface, which is beneficial for the formation of a stacked structure with a specific morphology on the support surface. This is conducive to the adsorption of aromatic molecules, selectively prolonging the residence time and reaction time of aromatic molecules in feedstock oil (such as distillate oil) on the catalyst, and improving the aromatic removal activity of the catalyst.

[0048] The urea used in this invention can promote the dispersion of active metals. The principle is as follows: the active metal impregnation solution contains urea, which can react with the active metal components to form nickel tungstate compounds, reduce the interaction strength between the active metal and the support, promote the dispersion of the active metal components on the support surface, thereby improving the sulfidability of the active metal and thus improving the hydrogenation activity of the catalyst.

[0049] In one specific embodiment of the catalyst described above in this invention, the active metal impregnation solution contains urea, butanediol, and alanine.

[0050] In one specific embodiment of the catalyst described above in this invention, the drying is performed at 50-150°C for 2-40 hours.

[0051] Preferably, the drying process is carried out at 50-120℃ for 2-20 hours.

[0052] In one specific embodiment of the catalyst described above in this invention, the calcination is carried out in an oxygen-containing atmosphere, the calcination temperature is 300-600℃, and the time is 2-20h.

[0053] Preferably, the roasting temperature is 300-550℃ and the time is 2-15h.

[0054] In one specific embodiment of the catalyst described above in this invention, the auxiliary agent includes Si or Ti, etc.

[0055] On the other hand, the present invention also provides a method for preparing the catalyst for deep removal of aromatics described above, wherein the preparation method includes:

[0056] (1) Add Ni precursor and W precursor to deionized water. After they are completely dissolved and the resulting solution is transparent, add urea and C1-C8 alcohols, then add amino acids. Mix well to obtain active metal impregnation solution.

[0057] (2) The γ-Al2O3 support or the γ-Al2O3 support modified with additives is impregnated in the active metal impregnation solution, and then dried and calcined to obtain the catalyst for deep removal of aromatics.

[0058] In one specific embodiment of the preparation method described above in this invention, the precursor of Ni includes nickel nitrate, and the precursor of W includes ammonium metatungstate.

[0059] In one specific embodiment of the preparation method described above, the impregnation is an equal-volume impregnation. Furthermore, the present invention does not specify a particular impregnation time, which can be reasonably adjusted according to the actual needs of on-site operations.

[0060] This invention does not specify the order in which urea and C1-C8 alcohols are added. The order can be adjusted as needed, but it is necessary to ensure that urea and C1-C8 alcohols are added first, followed by amino acids.

[0061] The γ-Al2O3 support and the additive-modified γ-Al2O3 support can be prepared using existing conventional methods. As in some embodiments of the present invention, the preparation method of the γ-Al2O3 support includes the following specific steps:

[0062] The pseudoboehmite powder and a certain proportion of Tianqing powder were mixed evenly, and then the adhesive solvent, deionized water and other ingredients were added and kneaded. Then the mixture was extruded, dried and calcined to obtain γ-Al2O3 support.

[0063] The preparation method of the γ-Al2O3 support modified with the additives includes the following specific steps:

[0064] The pseudoboehmite powder and a certain proportion of Tianqing powder and the precursor of the additive were mixed evenly, and then the adhesive solvent, deionized water and other ingredients were added and kneaded. Then the mixture was extruded, dried and calcined to obtain the additive-modified γ-Al2O3 carrier.

[0065] In another aspect, the present invention also provides the application of the catalyst described above for deep removal of aromatics in the deep removal of aromatics from distillate oils.

[0066] As a specific embodiment of the application described above in this invention, the application includes: using the catalyst for deep removal of aromatics to deeply remove aromatics from straight-run kerosene to obtain No. 3 jet fuel;

[0067] The aromatic content of the No. 3 jet fuel is no more than 20.0 vol%, and the smoke point is no less than 25.0 mm.

[0068] In preparing the catalyst for deep removal of aromatics, this invention incorporates three functional additives—urea, C1-C8 alcohols, and amino acids—during the preparation of the active metal impregnation solution. C1-C8 alcohols, with their excellent water solubility, reduce the surface tension of the aqueous solution, promoting / enhancing the migration of active metals within the carrier pores and maximizing the utilization of the carrier surface. Urea promotes the dispersion of active metals. Amino acids, possessing both W-loving carboxyl groups and Ni-loving amino groups, can complex with active metals to form complexes, promoting appropriate aggregation of active metals on the carrier surface. This facilitates the formation of a stacked structure with a specific morphology, which is beneficial for the adsorption of aromatic molecules. It selectively prolongs the residence time and reaction time of aromatic molecules in the feedstock oil (such as distillate oil) on the catalyst, thereby improving the catalyst's aromatic removal activity.

[0069] In summary, by adding appropriate proportions of urea, C1-C8 alcohols, and amino acids during the preparation of the active metal impregnation solution, this invention can significantly improve the aromatic saturation capacity and desulfurization and denitrification performance of the prepared catalyst. Attached Figure Description

[0070] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0071] Figure 1 Transmission electron microscopy (TEM) image of the catalyst for deep removal of aromatics provided in Example 1 of this invention.

[0072] Figure 2 Transmission electron microscopy (TEM) image of the catalyst for deep removal of aromatics provided in Example 2 of this invention.

[0073] Figure 3 Transmission electron microscopy (TEM) image of the catalyst for deep removal of aromatics provided in Example 3 of this invention.

[0074] Figure 4 Transmission electron microscopy (TEM) image of the catalyst for deep removal of aromatics provided in Example 4 of this invention.

[0075] Figure 5 Transmission electron microscopy image of the catalyst used for removing aromatics provided for Comparative Example 1.

[0076] Figure 6 Transmission electron microscopy image of the catalyst used for removing aromatics provided for Comparative Example 2.

[0077] Figure 7Transmission electron microscopy image of the catalyst used for removing aromatics provided for Comparative Example 3. Detailed Implementation

[0078] It should be noted that the term "comprising" and any variations thereof in the specification, claims, and accompanying drawings of this invention are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0079] The "range" disclosed in this invention is given in the form of a lower limit and an upper limit. It can be one or more lower limits and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower and upper limits define the boundaries of the particular range. All ranges defined in this way are composable, meaning that any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for specific parameters, it is also expected that ranges of 60-110 and 80-120 are also expected. Furthermore, if the listed minimum range values ​​are 1 and 2, and the listed maximum range values ​​are 3, 4, and 5, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0080] In this invention, unless otherwise specified, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are both real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this invention, and "0-5" is simply a shortened representation of these numerical combinations.

[0081] In this invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in this invention can be combined with each other to form new technical solutions.

[0082] In this invention, unless otherwise specified, all technical features and preferred features mentioned in this invention can be combined with each other to form new technical solutions.

[0083] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying tables, drawings, and embodiments. The embodiments described below are some, but not all, embodiments of this invention, and are only used to illustrate the invention, and should not be considered as limiting the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0084] Example 1

[0085] This embodiment provides a catalyst for deep removal of aromatics, which is prepared by a method including the following specific steps:

[0086] (1) Preparation of γ-Al2O3 support:

[0087] Weigh 1000g of boehmite powder, 53g of Tianqing powder, 22g of citric acid, and measure 650mL of 3-5% dilute nitric acid. Mix them evenly, extrude them using an extruder, dry them at 110℃ for 10h, and calcine them at 560℃ in air to obtain γ-Al2O3 support.

[0088] (2) Preparation of W-Ni impregnation solution containing additives:

[0089] Weigh 600g of deionized water, add 450g of ammonium metatungstate and 306g of nickel nitrate, and heat to 70℃ while stirring. Once completely dissolved and the solution is clear, add 2.5g of urea and 1g of butanediol, and maintain the temperature for 2 hours. Then add 2.25g of alanine and continue maintaining the temperature for 4 hours. After the temperature maintenance period, allow it to cool naturally to room temperature, and dilute to 700ml with deionized water.

[0090] (3) Preparation of W-Ni / γ-Al2O3 catalyst:

[0091] Weigh 500g of the carrier prepared in step (1), measure 350mL of the impregnation solution prepared in step (2), impregnate with an equal volume for 60min, dry at 110℃ for 7h, and calcine at 480℃ for 8h to obtain the catalyst product.

[0092] Example 2

[0093] This embodiment provides a catalyst for deep removal of aromatics, which is prepared by a method including the following specific steps:

[0094] (1) Preparation of Ti-containing γ-Al2O3 support:

[0095] Weigh 950g of boehmite powder, 50g of metatitanic acid, 45g of Tianqing powder, 22g of citric acid, and measure 660mL of 3-5% dilute nitric acid. Mix them evenly, extrude them into shape using an extruder, dry them at 120℃ for 10h, and calcine them at 540℃ in air atmosphere to obtain Ti-containing γ-Al2O3 support.

[0096] (2) Preparation of W-Ni impregnation solution containing additives:

[0097] Weigh 600g of deionized water, add 450g of ammonium metatungstate and 306g of nickel nitrate, and heat to 70℃ while stirring. Once completely dissolved and the solution is clear, add 2.5g of urea and 2.1g of butanediol, and maintain the temperature for 2.5 hours. Then add 1.4g of alanine and continue to maintain the temperature for 4 hours. After the temperature maintenance period, allow it to cool naturally to room temperature, and dilute to 700ml with deionized water.

[0098] (3) Preparation of W-Ni / γ-Al2O3 catalyst:

[0099] Weigh 500g of the carrier prepared in step (1), measure 348mL of the impregnation solution prepared in step (2), impregnate with an equal volume for 60min, dry at 110℃ for 7h, and calcine at 480℃ for 8h to obtain the catalyst product.

[0100] Example 3

[0101] This embodiment provides a catalyst for deep removal of aromatics, which is prepared by a method including the following specific steps:

[0102] (1) Preparation of Si-containing γ-Al2O3 support:

[0103] Weigh 950g of boehmite powder, 50g of silica sol, 44g of Tianqing powder, 22g of citric acid, and measure 660mL of 3-5% dilute nitric acid. Mix them evenly, extrude them into shape using an extruder, dry them at 120℃ for 10h, and calcine them at 540℃ in air atmosphere to obtain a Si-containing γ-Al2O3 support.

[0104] (2) Preparation of W-Ni impregnation solution containing additives:

[0105] Weigh 600g of deionized water, add 450g of ammonium metatungstate and 306g of nickel nitrate, and heat to 72℃ while stirring. Once completely dissolved and the solution is clear, add 4.25g of urea and 1g of butanediol, and maintain the temperature for 2 hours. Then add 1.4g of alanine and continue maintaining the temperature for 4 hours. After the temperature maintenance period, allow it to cool naturally to room temperature, and dilute to 700ml with deionized water.

[0106] (3) Preparation of W-Ni / γ-Al2O3 catalyst:

[0107] Weigh 500g of the support prepared in step (1), measure 347mL of the impregnation solution prepared in step (2), impregnate with an equal volume for 60min, dry at 110℃ for 7h, and calcine at 480℃ for 8h to obtain the catalyst product.

[0108] Example 4

[0109] This embodiment provides a catalyst for deep removal of aromatics, which is prepared by a method including the following specific steps:

[0110] (1) Preparation of γ-Al2O3 support:

[0111] Weigh 1000g of boehmite powder, 53g of Tianqing powder, 22g of citric acid, and measure 650mL of 3-5% dilute nitric acid. Mix them evenly, extrude them using an extruder, dry them at 110℃ for 10h, and calcine them at 560℃ in air to obtain γ-Al2O3 support.

[0112] (2) Preparation of W-Ni impregnation solution containing additives:

[0113] Weigh 600g of deionized water, add 450g of ammonium metatungstate and 306g of nickel nitrate, and heat to 70℃ while stirring. Once completely dissolved and the solution is clear, add 3g of urea and 1.5g of butanediol, and maintain the temperature for 2.5 hours. Then add 2g of alanine and continue maintaining the temperature for 4 hours. After the temperature maintenance period, allow it to cool naturally to room temperature, and dilute to 700mL with deionized water.

[0114] (3) Preparation of W-Ni / γ-Al2O3 catalyst:

[0115] Weigh 500g of the carrier prepared in step (1), measure 350mL of the impregnation solution prepared in step (2), impregnate with an equal volume for 60min, dry at 110℃ for 7h, and calcine at 480℃ for 8h to obtain the catalyst product.

[0116] Comparative Example 1

[0117] This comparative example provides a catalyst for the removal of aromatics, which is prepared by a method comprising the following specific steps:

[0118] (1) Preparation of γ-Al2O3 support:

[0119] Weigh 1000g of boehmite powder, 53g of Tianqing powder, 22g of citric acid, and measure 650mL of 3-5% dilute nitric acid. Mix them evenly, extrude them using an extruder, dry them at 110℃ for 10h, and calcine them at 560℃ in air to obtain γ-Al2O3 support.

[0120] (2) Preparation of W-Ni impregnation solution:

[0121] Weigh 600g of deionized water, add 450g of ammonium metatungstate and 306g of nickel nitrate, and heat to 70℃ while stirring. Once completely dissolved and the solution is transparent, continue to maintain the temperature for 4 hours. After the temperature is maintained, allow it to cool naturally to room temperature, and then dilute to 700mL with deionized water for later use.

[0122] (3) Preparation of W-Ni / γ-Al2O3 catalyst:

[0123] Weigh 500g of the carrier prepared in step (1), measure 350mL of the impregnation solution prepared in step (2), impregnate with an equal volume for 60min, dry at 110℃ for 7h, and calcine at 480℃ for 8h to obtain the catalyst product.

[0124] Comparative Example 2

[0125] This comparative example provides a catalyst for the removal of aromatics, which is prepared by a method comprising the following specific steps:

[0126] (1) Preparation of Ti-containing γ-Al2O3 support:

[0127] Weigh 950g of boehmite powder, 50g of metatitanic acid, 45g of Tianqing powder, 22g of citric acid, and measure 660mL of 3-5% dilute nitric acid. Mix them evenly, extrude them into shape using an extruder, dry them at 120℃ for 10h, and calcine them at 540℃ in air atmosphere to obtain Ti-containing γ-Al2O3 support.

[0128] (2) Preparation of W-Ni impregnation solution:

[0129] Weigh 600g of deionized water, add 450g of ammonium metatungstate and 306g of nickel nitrate, and heat to 70℃ while stirring. Once completely dissolved and the solution is transparent, continue to maintain the temperature for 4 hours. After the temperature is maintained, allow it to cool naturally to room temperature, and then dilute to 700mL with deionized water for later use.

[0130] (3) Preparation of W-Ni / γ-Al2O3 catalyst:

[0131] Weigh 500g of the carrier prepared in step (1), measure 348mL of the impregnation solution prepared in step (2), impregnate with an equal volume for 60min, dry at 110℃ for 7h, and calcine at 480℃ for 8h to obtain the catalyst product.

[0132] Comparative Example 3

[0133] This comparative example provides a catalyst for the removal of aromatics, which is prepared by a method comprising the following specific steps:

[0134] (1) Preparation of Si-containing γ-Al2O3 support:

[0135] Weigh 950g of boehmite powder, 50g of silica sol, 44g of Tianqing powder, 22g of citric acid, and measure 660mL of 3-5% dilute nitric acid. Mix them evenly, extrude them into shape using an extruder, dry them at 120℃ for 10h, and calcine them at 540℃ in air atmosphere to obtain a Si-containing γ-Al2O3 support.

[0136] (2) Preparation of W-Ni impregnation solution:

[0137] Weigh 600g of deionized water, add 450g of ammonium metatungstate and 306g of nickel nitrate, and heat to 70℃ while stirring. Once completely dissolved and the solution is transparent, continue to maintain the temperature for 4 hours. After the temperature is maintained, allow it to cool naturally to room temperature, and then dilute to 700mL with deionized water for later use.

[0138] (3) Preparation of W-Ni / γ-Al2O3 catalyst:

[0139] Weigh 500g of the support prepared in step (1), measure 347mL of the impregnation solution prepared in step (2), impregnate with an equal volume for 60min, dry at 110℃ for 7h, and calcine at 480℃ for 8h to obtain the catalyst product.

[0140] In the above seven examples, Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3 correspond to each other. In Examples 1-3, urea, butanediol and alanine were added in a certain proportion, while in Comparative Examples 1-3, urea, butanediol and alanine were not added.

[0141] Test Example 1

[0142] In this test case, the catalysts provided in Examples 1-4 and Comparative Examples 1-3 were analyzed by transmission electron microscopy (TEM). The obtained TEM images are shown below. Figures 1-7 As shown.

[0143] Depend on Figures 1-4It can be seen that the catalysts provided in Examples 1-4 of this invention have obvious stacking structures with specific morphologies on their surfaces, while from... Figures 5-7 As can be seen from the above, the catalysts provided in Comparative Examples 1-3 did not exhibit the stacking structure with the specific morphology. Therefore, it can be concluded that in preparing the catalyst for deep removal of aromatics, the present invention adds three functional additives—urea, butanediol, and alanine—during the preparation of the active metal impregnation solution. Among these, amino acids possess both W-loving carboxyl groups and Ni-loving amino groups, enabling them to complex the active metal into a complex, promoting appropriate aggregation of the active metal on the support surface, and facilitating the formation of a stacking structure with the specific morphology of the active metal on the support surface.

[0144] In addition, in comparison Figures 1-3 and Figures 5-7 It can be seen that in the catalyst provided in the embodiments of the present invention, the active metal tends to be distributed in the pores of the support, so that the surface of the support is fully utilized. This is because the C1-C8 alcohols added in the embodiments have good water solubility, which can reduce the surface tension of the aqueous solution and promote / enhance the migration of the active metal in the pores of the support, so that the surface of the support is fully utilized.

[0145] Test Example 2

[0146] In this test example, the catalysts provided in Examples 1-4 and Comparative Examples 1-3 were used to evaluate the hydrogenation activity on a 200 mL scale. The feedstock was a low-quality kerosene from a petrochemical company. Before evaluation, the catalysts were pre-sulfurized for 20 h in a hydrogen atmosphere at 330 °C using kerosene containing 2 wt% carbon disulfide and a pressure of 7.0 MPa, and then fed into the feedstock.

[0147] The reaction conditions for evaluating the hydrogenation activity were: reaction temperature 325℃, pressure 6.0 MPa, and space velocity (volume) 1.5 h⁻¹. -1 And the hydrogen-to-oil (volume) ratio is 400.

[0148] The properties of the feedstock oils used in this test example are shown in Tables 1 and 2 below. The hydrogenation activity evaluation results of the catalysts provided in Examples 1-4 are shown in Table 1, and the hydrogenation activity evaluation results of the catalysts provided in Comparative Examples 1-3 are shown in Table 2.

[0149] Table 1. Properties of feedstock oil and evaluation results of the hydrogenation activity of the catalysts provided in the examples.

[0150] Analysis Project raw material Example 1 Example 2 Example 3 Example 4 <![CDATA[Density, g / cm 3 (at 20 °C)]]> 0.8031 0.7945 0.7946 0.7942 0.7941 Distillation range, °C Initial boiling point 174 175 174 175 174

[0151] Final boiling point 242 240 240 239 239 Sulfur content, μg / g 3380 2.0 1.8 2.1 2.0 Nitrogen content, μg / g 17.0 0.5 0.5 0.5 0.5 Smoke point, mm 20.2 27.4 27.1 27.5 27.3 Mass spectrometry composition, wt% Alkanes 42.4 45.0 44.4 45.7 44.6 Total cycloalkanes 37.1 46.6 46.9 46.3 46.7 Total aromatics 20.5 8.4 8.7 8.0 8.7 Monocyclic aromatic hydrocarbons 19.2 8.4 8.7 8.0 8.7 Bicyclic aromatic hydrocarbons 1.3 0 0 0 0 Tricyclic aromatic hydrocarbons 0 0 0 0 0

[0152] Table 2. Properties of feedstock oils and evaluation results of the hydrogenation activity of the catalysts provided in the comparative examples.

[0153] Analysis Project raw material Comparative Example 1 Comparative Example 2 Comparative Example 3 <![CDATA[Density, g / cm 3 (at 20 °C)]]> 0.8031 0.7942 0.7947 0.7948 Distillation range, °C Initial boiling point 174 174 176 175 Final boiling point 242 240 239 240 Sulfur content, μg / g 3380 11.9 14.2 14.4 Nitrogen content, μg / g 17.0 3.5 4.0 4.0 Smoke point, mm 20.2 23.5 23.7 23.3 Mass spectrometry composition, wt% Alkanes 42.4 45.2 45.0 44.8 Total cycloalkanes 37.1 42.3 42.1 42.3 Total aromatics 20.5 12.5 12.9 12.9 Monocyclic aromatic hydrocarbons 19.2 12.1 12.4 12.4 Bicyclic aromatic hydrocarbons 1.3 0.4 0.5 0.5 Tricyclic aromatic hydrocarbons 0 0 0 0

[0154] As can be seen from Tables 1 and 2, compared with the catalysts provided in Comparative Examples 1-3, the catalysts provided in the embodiments of the present invention have significantly improved hydrogenation activity, greater increases in aromatic saturation ratio and smoke point, and higher desulfurization and denitrification rates.

[0155] In the preparation of the catalyst for deep removal of aromatics described in this embodiment of the invention, three functional additives, urea, butanediol, and alanine, are added during the preparation of the active metal impregnation solution. Butanediol has good water solubility, which can reduce the surface tension of the aqueous solution, thus promoting / enhancing the migration of the active metal within the carrier pores and fully utilizing the carrier surface. Urea promotes the dispersion of the active metal. Alanine has both a W-loving carboxyl group and a Ni-loving amino group, enabling it to complex the active metal into a complex, promoting appropriate aggregation of the active metal on the carrier surface. This facilitates the formation of a stacked structure with a specific morphology on the carrier surface, thereby promoting the adsorption of aromatic molecules, selectively prolonging the residence time and reaction time of aromatic molecules in the feedstock oil (such as distillate oil) on the catalyst, and improving the aromatic removal activity of the catalyst.

[0156] It is evident that the three functional additives used in this invention—urea, C1-C8 alcohols, and amino acids—have a synergistic effect. All three functional additives must be used simultaneously to achieve the goal of preparing the catalyst with excellent properties such as high aromatic hydrocarbon removal activity for deep aromatic hydrocarbon removal provided by this invention. If any one or any two of these three functional additives are used alone to prepare the catalyst, the prepared active metal impregnation solution will be unstable and cannot be used to prepare the catalyst.

[0157] In summary, by adding appropriate proportions of urea, butanediol, and alanine during the preparation of the active metal impregnation solution, the present invention can significantly improve the aromatic saturation capacity and desulfurization and denitrification performance of the prepared catalyst.

[0158] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made within the scope of protection of this patent should still fall within the scope of this patent. Furthermore, the technical features, technical features and technical inventions, and technical inventions in this invention can be freely combined and used.

Claims

1. The application of a catalyst for deep removal of aromatics in distillate oil, characterized in that, The catalyst for deep removal of aromatics is obtained by first impregnating a γ-Al2O3 support or an additive-modified γ-Al2O3 support with an active metal impregnation solution, and then drying and calcining it. The active metal impregnation solution contains urea, C1-C8 alcohols, and amino acids; wherein the amino acids include one or a combination of several of glycine, alanine, leucine, isoleucine, methionine, phenylalanine, glutamine, threonine, glutamic acid, and lysine. In the catalyst for deep removal of aromatics, the active metal is distributed on the surface of the support and in the pores of the support, and the active metal forms a stacked structure on the surface of the support. The active metals include Ni and W.

2. The application according to claim 1, characterized in that, The application includes: using the catalyst for deep removal of aromatics to deeply remove aromatics from straight-run kerosene to obtain No. 3 jet fuel; The aromatic content of the No. 3 jet fuel is no more than 20.0 v%, and the smoke point is no less than 25.0 mm.

3. The application according to claim 1 or 2, characterized in that, In the active metal impregnation solution, the mass ratio of urea, C1-C8 alcohols, and amino acids is 45-88:18-44:26-47.

4. The application according to claim 3, characterized in that, In the active metal impregnation solution, the mass ratio of urea, C1-C8 alcohols, and amino acids is 50-85:20-42:28-45.

5. The application according to claim 1 or 2, characterized in that, The C1-C8 alcohols include one or a combination of several of methanol, ethanol, ethylene glycol, propanol, glycerol, butanol, butanediol, pentanol, hexanol, octanol, and methylcyclohexanol.

6. The application according to claim 5, characterized in that, The C1-C8 alcohols mentioned are butanediol.

7. The application according to claim 1 or 2, characterized in that, The amino acid in question is alanine.

8. The application according to claim 1 or 2, characterized in that, The active metal impregnation solution contains urea, butanediol, and alanine.

9. The application according to claim 1 or 2, characterized in that, The drying process involves drying at 50-150℃ for 2-40 hours.

10. The application according to claim 9, characterized in that, The drying process involves drying at 50-120℃ for 2-20 hours.

11. The application according to claim 1 or 2, characterized in that, The calcination is carried out in an oxygen-containing atmosphere at a temperature of 300-600℃ for 2-20 hours.

12. The application according to claim 11, characterized in that, The roasting temperature is 300-550℃, and the time is 2-15h.

13. The application according to claim 1 or 2, characterized in that, The additives include Si or Ti.

14. The application according to claim 1 or 2, characterized in that, The method for preparing the catalyst for deep removal of aromatics includes: (1) Add Ni precursor and W precursor to deionized water. After they are completely dissolved and the resulting solution is transparent, add urea and C1-C8 alcohols, then add amino acids. After mixing evenly, an active metal impregnation solution is obtained. (2) The γ-Al2O3 support or the γ-Al2O3 support modified with additives is impregnated in the active metal impregnation solution, and then dried and calcined to obtain the catalyst for deep removal of aromatics.

15. The application according to claim 14, characterized in that, The precursor of Ni includes nickel nitrate, and the precursor of W includes ammonium metatungstate.

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