A hydrogenation catalyst and its preparation method, and a hydrogenation production process for reformed oil.

Abstract

A hydrogenation catalyst is disclosed, using alumina as a support, on which molecular sieves and active components are loaded, including noble metals and promoter metals. The noble metals are Pt and / or Pd, and the promoter metals are Ni and / or Co. By weight of the catalyst, the molecular sieve accounts for 1-10%, the noble metals for 0.01-0.5% (based on elemental composition), and the promoter metals for 0.1-5% (based on elemental composition). The molecular sieves are loaded on the outer surface of the catalyst. This invention sequentially loads promoter metals and noble metals onto a support, and then obtains the catalyst through hydrothermal mixing with a molecular sieve precursor. This approach improves the contact area between the molecular sieve and the active metal, and facilitates the loading of the molecular sieve onto the active sites of the active metal, fully utilizing the molecular sieve's ability to donate H protons and enhancing the catalyst's hydrogenation activity. Furthermore, it increases the utilization rate of the molecular sieve, thus reducing the amount of molecular sieve used and lowering the catalyst cost. It exhibits higher olefin saturation activity and selectivity for the hydrotreating of reformed oils.

Description

Technical Field

[0001] This invention relates to the field of oil hydrogenation technology, specifically to a hydrogenation catalyst, its preparation method, and a hydrogenation production process for reformed oil. Background Technology

[0002] To adapt to the chemical transformation and development of oil refining enterprises, a large number of reforming units have been built to produce aromatics. While the reformed product oil has a high aromatic content, it still contains a small amount of olefins. These olefins tend to accumulate in the reflux aromatics during aromatics extraction, affecting the aromatic content, and are also prone to polymerization, contaminating the extraction solvent. Furthermore, the oxidation of olefins produces organic acids, causing severe corrosion of the extraction system equipment. In addition, if the olefins are not removed, the bromine index and acid wash color of the aromatic products may fail to meet standards, and the bromine index and copper strip corrosion test of the solvent oil may also fail. Therefore, the reformed product oil needs to undergo olefin removal treatment.

[0003] CN202110763635.7 discloses a hydrogenation catalyst, its preparation method, and its application in the removal of olefins from reformed C5 oil. The catalyst preparation process involves mixing aluminum hydroxide dry adhesive, a binder, a titanium dioxide precursor, and a pore-expanding agent in an acidic aqueous solution, molding, drying, and calcining to obtain a catalyst support. Then, the catalyst support is impregnated in a mixed solution containing a nickel source and an additive, followed by drying and calcination to obtain the hydrogenation catalyst. This catalyst can be applied to evaluate the removal of olefins from reformed C5 oil in a fixed fluidized bed. The active component of this catalyst is metallic nickel, which has low activity and cannot meet the requirements for olefin removal from the C8 component in the reformed oil. Typically, the olefin bromine index before xylene extraction needs to be <20 mgBr / 100 g oil.

[0004] CN201410588224.9 discloses a selective hydrogenation catalyst for reformed oil, its preparation method, and its application. The catalyst comprises the following components by mass fraction: 0.05-0.5% active component, 0.5-10% promoter, and the remainder as a support; the active component is at least one selected from Pt, Pd, and Ru; the promoter is one or two selected from Na, K, Mg, Ca, Co, Fe, Ni, Mo, and Cu; the support is a porous Al₂O₃; the active component is distributed in an eggshell pattern on the support, and the thickness of the eggshell is less than 1 mm; the specific surface area of ​​the catalyst is 50-400 m². 2 / g, pore volume 0.2-1.2cm³ 3 / g, of which pores with a diameter of 5-50 nm account for 50-80% of the total pores. This catalyst requires a high hydrogen-to-oil volume ratio (hydrogen-to-oil ratio of 100-1000) and a low space velocity (feed space velocity of 1 h⁻¹). -1 -6h -1Meeting product quality requirements under certain conditions leads to increased hydrogen consumption in the unit, and low feedstock space velocity increases the amount of precious metals loaded, thus increasing production costs.

[0005] CN200810104300.9 discloses a catalyst for selective hydrodeolefins treatment of continuous reformed gasoline and its preparation method. The catalyst is characterized by an eggshell-shaped distribution of the precious metal active component on the support. This has advantages in two aspects: firstly, it improves the utilization rate of the precious metal active component, reduces its content, and lowers the catalyst cost; secondly, it reduces the activity of aromatics hydrogenation, improves the selectivity of olefins hydrogenation, and reduces aromatics hydrogenation loss. However, the active metal in this catalyst is distributed in the outer shell. During operation or catalyst regeneration, catalyst wear can easily occur, leading to the loss of the precious metal in the outer shell and a decrease in catalyst activity. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention starts with the mechanism of olefin hydrogenation reaction and prepares a hydrogenation catalyst by improving the dispersion of active metals and increasing the acid content. This catalyst has high saturated activity and selectivity for olefin hydrogenation, is suitable for trickle bed and liquid phase hydrogenation processes, and is especially suitable for the hydrogenation process of reformed oil.

[0007] To achieve the above technical objectives, the technical solution of the present invention is as follows:

[0008] The technical objective of the first aspect of this invention is to provide a hydrogenation catalyst, using alumina as a support, on which molecular sieves and active components are loaded. The active components include noble metals and auxiliary metals, wherein the noble metals are Pt and / or Pd, and the auxiliary metals are Ni and / or Co. By weight of the catalyst, the molecular sieves account for 1-10%, preferably 2-8%, more preferably 3-5%; the noble metals, in elemental form, account for 0.01-0.5%, preferably 0.02-0.3%; and the auxiliary metals, in elemental form, account for 0.1-5%, preferably 1-3%. The molecular sieves are loaded on the outer surface of the catalyst.

[0009] Furthermore, the noble metal and auxiliary metal in the catalyst exist in their oxide or elemental form.

[0010] Furthermore, the molecular sieve supported on the outer surface of the catalyst may be supported on a noble metal, and / or on an auxiliary metal, and / or on an alumina support.

[0011] Furthermore, the molecular sieve is selected from at least one of Y-type molecular sieve, ZSM-5 molecular sieve, β-type molecular sieve and MCM-41 molecular sieve.

[0012] The second aspect of the present invention aims to provide a method for preparing the above-mentioned hydrogenation catalyst, comprising the following steps:

[0013] (1) The alumina support was impregnated with an impregnation solution containing auxiliary metal salts, and the catalyst precursor A was obtained by drying and calcining.

[0014] (2) Catalyst precursor A is impregnated with an impregnation solution containing precious metal salts and organic additives, and then dried and calcined to obtain catalyst precursor B.

[0015] (3) The catalyst precursor B is mixed with the molecular sieve precursor and subjected to hydrothermal treatment, followed by drying and calcination to obtain the hydrogenation catalyst.

[0016] Furthermore, before use, the catalyst undergoes a reduction treatment process, in which the precious metal and auxiliary metal are reduced to their elemental forms. The conditions for the reduction treatment are: in a hydrogen atmosphere, a reduction temperature of 200-550℃, a reduction pressure of 2.0-4.0 MPa, and a reduction time of 3-10 hours.

[0017] Furthermore, the auxiliary metal salt mentioned in step (1) is a nitrate, acetate or sulfate of the auxiliary metal, and its preparation method is well known to those skilled in the art, using equal volume impregnation or supersaturated impregnation.

[0018] Furthermore, the drying conditions in step (1) are: drying temperature 60-150℃, drying time 3-6 hours. The calcination conditions are: calcination temperature 200-300℃, calcination time 3-6 hours.

[0019] Furthermore, in step (2), the precious metal platinum salt is selected from at least one of chloroplatinic acid, dichlorotetramineplatinum, ammonium chloroplatinate, platinum trichloride, platinum tetrachloride, dicarbonyl platinum dichloride, dinitrodiaminoplatinum, and sodium tetranitroplatinate, and the concentration in the solution is 0.001-0.5 g / mL based on platinum element.

[0020] Furthermore, in step (2), the precious metal palladium salt is selected from at least one of palladium chloride, palladium nitrate, palladium acetate, sodium tetrachloropalladium, dichlorotetraamminepalladium, palladium trifluoroacetate, palladium diacetylacetonate, and palladium hexafluoroacetylacetonate, and the concentration of palladium in the solution is 0.001-0.5 g / mL.

[0021] Further, the organic auxiliary agent in step (2) is an alcohol or organic acid containing hydroxyl and / or carboxyl groups with 3-10 carbon atoms. Specifically, it is selected from at least one of ethylene glycol, glycerol, butanediol, pentanediol, acetic acid, citric acid, malonic acid, succinic acid, and glutaric acid. The amount of the organic auxiliary agent added is 3-10 wt% of the alumina carrier, preferably 3-8 wt%.

[0022] Furthermore, the drying conditions in step (2) are: drying temperature 60-100℃, drying time 3-6 hours. The calcination conditions are: calcination temperature 200-300℃, calcination time 3-6 hours.

[0023] Furthermore, the molecular sieve precursor in step (3) is a gel formed by mixing a silicon source and / or an aluminum source, a precipitant, a template agent, and water. Its preparation method is well known to those skilled in the art, and the molecular sieve is formed using a precipitation method or a sol-gel method. The silicon source is selected from one or more of sodium silicate, tetraethyl orthosilicate, silica sol, and chromatographic silica gel; the aluminum source is selected from one or more of sodium aluminate, aluminum hydroxide, and boehmite; the precipitant is selected from at least one of sodium hydroxide, ammonia, and potassium hydroxide; and the template agent is selected from one or more of hexadecyltrimethylammonium bromide, ethylenediamine, n-butylamine, tetrapropylammonium bromide, ethanol, tetraethylammonium hydroxide, tetraethylammonium bromide, triethylamine, di-n-propylamine, diisopropylamine, and methylcellulose.

[0024] Furthermore, the hydrothermal treatment conditions in step (3) are: temperature of 90-200℃, preferably 120-200℃; pressure of 0.1-2.0MPa; pH of 7.5-9.0; and time of 5-48 hours.

[0025] Furthermore, the drying conditions in step (3) are: drying temperature 90-200℃, drying time 3-6 hours. The calcination conditions are: calcination temperature 300-500℃, calcination time 3-6 hours.

[0026] The technical objective of the third aspect of this invention is to provide a hydrotreating process for reformed oil, wherein the oil reacts with the above-mentioned hydrotreating catalyst or the hydrotreating catalyst prepared by the above method.

[0027] Furthermore, in the above-mentioned hydrotreating process, the catalyst catalyzes the hydrodeolefination of the reformed oil, the reaction temperature is 130-280℃, preferably 130-190℃; the pressure is 1.0-3.0 MPa; and the volume ratio of hydrogen to feedstock oil is 10-1000.

[0028] The catalyst described in this invention can effectively remove olefins from reformed oils with a bromine index higher than 3500 mgBr / 100g oil, exhibiting good selective olefin removal and minimal aromatic loss.

[0029] Compared with the prior art, the catalyst of the present invention has the following advantages:

[0030] (1) The addition of molecular sieves to the hydrogenation catalyst of the present invention, and the molecular sieves being loaded on the outer surface of the catalyst instead of being mixed with the support, is beneficial to increasing the contact area between the molecular sieves and the active metal, and at the same time, it is beneficial to load the molecular sieves onto the active sites of the active metal, giving full play to the ability of the molecular sieves to provide H protons and improving the hydrogenation activity of the catalyst; on the other hand, it increases the utilization rate of the molecular sieves, thus reducing the amount of molecular sieves used and reducing the cost of the catalyst.

[0031] (2) In the preparation method of the present invention, Ni and / or Co metals are first loaded onto a support, then Pt and / or Pd metals are loaded, and then molecular sieves are loaded. Loading Ni and / or Co metals onto the support can modify the highly active sites on the support surface, weaken the interaction between the support and Pt and / or Pd metals, and improve the dispersion of Pt and / or Pd metals, which is beneficial for the uniform distribution of the noble metal active group in the pores and surface of the support. The loaded Ni and / or Co metals can protect the noble metal components. When there are impurities such as sulfides in the raw oil or hydrogen, they are more likely to form sulfides with Ni and / or Co, thus achieving the purpose of protecting the noble metal components.

[0032] (3) The catalyst of the present invention is used in the hydrotreating process of reformed oil.

[0033] Other features and advantages of the present invention will be described in detail in the following detailed description section. Detailed Implementation

[0034] The following non-limiting embodiments are intended to enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way.

[0035] The noble metal composition of the catalyst provided by this invention can be characterized by inductively coupled plasma (ICP), and the composition of the promoter metal in the catalyst can be characterized by chemical colorimetry. The dispersion of the noble metal in the catalyst provided by this invention can be determined by hydrogen-oxygen titration. Taking Pt as an example, the chemical reaction formulas for hydrogen-oxygen titration are formulas (1) to (3):

[0036] Pt + H2 → PtH (catalyst) (1)

[0037] PtH + O2 → PtO + H2O (Oxygen titration) (2)

[0038] PtO + H2 → PtH + H2O (hydrogen titration) (3)

[0039] Titration of one Pt atom using the hydrogen-oxygen titration method requires the consumption of three hydrogen atoms. The dispersion of the noble metal can be obtained by the ratio of the actual hydrogen consumption to the theoretical hydrogen consumption during the measurement process.

[0040] Example 1

[0041] (1) An equal volume of nickel nitrate solution was impregnated into an alumina support, and then dried at 100°C for 3 hours and calcined at 250°C for 3 hours to obtain catalyst precursor A.

[0042] (2) The catalyst precursor A prepared in step (1) is impregnated with a solution containing chloroplatinic acid and glycerol (5% of the carrier weight), then dried at 80°C for 6 hours and calcined at 300°C for 5 hours to obtain catalyst precursor B.

[0043] (3) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added to deionized water, with the molar ratio of each component being n(SiO2):n(Al2O3):n(Na2O):n(n-butylamine):n(H2O)=20:1:7:6:200. The mixture was stirred to form a homogeneous sol, which is the precursor of ZSM-5 molecular sieve. It was then mixed with the catalyst precursor B prepared in step (2), and then hydrothermally treated for 20 h at 120℃, 1.0 MPa and pH=8.5. After that, it was filtered, washed three times with deionized water, dried at 110℃ for 3 h, calcined at 450℃ for 3 h, and then reduced with hydrogen at a reduction temperature of 400℃, a reduction pressure of 3.0 MPa and a reduction time of 5 h to obtain catalyst C-1.

[0044] The weight percentages of each component in catalyst C-1 are as follows: Pt 0.15%, Ni 2.8%, ZSM-5 3.1%, and the remainder is the support.

[0045] Example 2

[0046] (1) An equal volume of cobalt nitrate solution was impregnated into an alumina support, and then dried at 100°C for 3 h and calcined at 250°C for 3 h to obtain catalyst precursor A.

[0047] (2) The catalyst precursor A prepared in step (1) is impregnated with a solution containing chloroplatinic acid and ethylene glycol (6% of the carrier weight), then dried at 80°C for 6 hours and calcined at 300°C for 5 hours to obtain catalyst precursor B.

[0048] (3) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added to deionized water, with the molar ratio of each component being n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O)=12:1:6:3:180. The mixture was stirred until a homogeneous sol was formed, which is the precursor of Y molecular sieve. It was then mixed with the catalyst precursor B prepared in step (2), and then hydrothermally treated for 10 h at 150 °C, 1.0 MPa and pH=8.0. After that, the mixture was filtered, washed three times with deionized water, dried at 110 °C for 3 h, calcined at 450 °C for 3 h, and then reduced with hydrogen at a reduction temperature of 400 °C, a reduction pressure of 3.0 MPa and a reduction time of 5 h to obtain catalyst C-2.

[0049] The weight percentages of the components in catalyst C-2 are as follows: Pt 0.25%, Co 3.0%, Y molecular sieve 3.2%, and the remainder is the support.

[0050] Example 3

[0051] (1) An equal volume of nickel nitrate solution was impregnated into an alumina support, and then dried at 120°C for 3 hours and calcined at 200°C for 4 hours to obtain catalyst precursor A.

[0052] (2) The catalyst precursor A prepared in step (1) is impregnated with a solution containing chloroplatinic acid and acetic acid (6% of the carrier weight), then dried at 90°C for 5 hours and calcined at 250°C for 5 hours to obtain catalyst precursor B.

[0053] (3) Dissolve sodium aluminate and sodium hydroxide in deionized water, then add tetraethylammonium bromide, stir vigorously, slowly add silica sol, and age for 3 hours. The molar ratio of each component is n(SiO2):n(Al2O3):n(Na2O):n(tetraethylammonium bromide):n(H2O)=25:1:6:5:250 to form a precursor of type b molecular sieve. Then mix it with the catalyst precursor B prepared in step (2), and then perform hydrothermal treatment at 130℃, 1.0MPa, and pH=8.5 for 15 hours. Then filter, wash three times with deionized water, dry at 110℃ for 3 hours, calcine at 450℃ for 3 hours, and then reduce with hydrogen at a reduction temperature of 500℃, a reduction pressure of 3.0MPa, and a reduction time of 5 hours to obtain catalyst C-3.

[0054] The weight percentages of the components in catalyst C-3 are as follows: Pt 0.28%, Ni 2.9%, b molecular sieve 3.5%, and the remainder is support.

[0055] Example 4

[0056] (1) An equal volume of nickel nitrate solution was impregnated into an alumina support, and then dried at 120°C for 3 hours and calcined at 200°C for 4 hours to obtain catalyst precursor A.

[0057] (2) The catalyst precursor A prepared in step (1) is impregnated with a solution containing palladium chloride and succinic acid (5% of the carrier weight), then dried at 90°C for 5 hours and calcined at 250°C for 5 hours to obtain catalyst precursor B.

[0058] (3) Mix hexadecyltrimethylammonium bromide with sodium hydroxide, then add it to deionized water. After stirring, add tetraethyl orthosilicate dropwise to the mixed solution. After stirring for 30 min, the molar ratio of each component is n(SiO2):n(Na2O):n(hexadecyltrimethylammonium bromide):n(H2O)=11:2:2:200 to form MCM-41 molecular sieve precursor. Mix it with catalyst precursor B prepared in step (2), and then perform hydrothermal treatment at 130℃, 1.0MPa, and pH=8.5 for 15 h. Then filter, wash three times with deionized water, dry at 110℃ for 3 h, calcine at 450℃ for 3 h, and then reduce it with hydrogen at a reduction temperature of 500℃, a reduction pressure of 3.0MPa, and a reduction time of 5 h to obtain catalyst C-4.

[0059] The weight percentages of the components in catalyst C-4 are as follows: Pd 0.15%, Ni 2.8%, MCM-41 molecular sieve 2.5%, and the remainder is the support.

[0060] Example 5

[0061] (1) An equal volume of cobalt nitrate solution was impregnated into an alumina support, and then dried at 120°C for 3 hours and calcined at 200°C for 4 hours to obtain catalyst precursor A.

[0062] (2) Impregnate the catalyst precursor A prepared in step (1) with a solution containing palladium chloride and acetic acid (6% of the carrier weight), then dry at 80°C for 5 hours and calcine at 300°C for 5 hours to obtain catalyst precursor B.

[0063] (3) Dissolve sodium aluminate and sodium hydroxide in deionized water, then add tetraethylammonium bromide, stir vigorously, slowly add silica sol, and age for 3 hours. The molar ratio of each component is n(SiO2):n(Al2O3):n(Na2O):n(tetraethylammonium bromide):n(H2O)=25:1:6:5:250 to form a precursor of type b molecular sieve. Then mix it with the catalyst precursor B prepared in step (2), and then perform hydrothermal treatment at 130℃, 1.0MPa, and pH=8.5 for 15 hours. Then filter, wash three times with deionized water, dry at 120℃ for 3 hours, calcine at 500℃ for 3 hours, and then reduce with hydrogen at a reduction temperature of 350℃, a reduction pressure of 2.0MPa, and a reduction time of 10 hours to obtain catalyst C-5.

[0064] The weight percentages of each component in catalyst C-5 are as follows: Pd 0.20%, Co 2.0%, β-zeolite 3.0%, and the remainder is support.

[0065] Example 6

[0066] (1) An equal volume of nickel nitrate solution was impregnated into an alumina support, and then dried at 100°C for 3 hours and calcined at 250°C for 4 hours to obtain catalyst precursor A.

[0067] (2) Impregnate the catalyst precursor A prepared in step (1) with a solution containing palladium chloride and citric acid (6% of the carrier weight), then dry at 80°C for 6 hours and calcine at 300°C for 5 hours to obtain catalyst precursor B.

[0068] (3) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added to deionized water, with the molar ratio of each component being n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O)=12:1:6:3:180. The mixture was stirred until a homogeneous sol was formed, which is the precursor of Y molecular sieve. It was then mixed with the catalyst precursor B prepared in step (2), and then hydrothermally treated for 10 h at 150 °C, 1.0 MPa and pH=8.0. After that, the mixture was filtered, washed three times with deionized water, dried at 110 °C for 3 h, calcined at 400 °C for 3 h, and then reduced with hydrogen at a reduction temperature of 300 °C, a reduction pressure of 3.0 MPa and a reduction time of 10 h to obtain catalyst C-6.

[0069] The weight percentages of the components in catalyst C-6 are as follows: Pd 0.30%, Ni 1.5%, Y molecular sieve 4.1%, and the remainder is the support.

[0070] Example 7

[0071] (1) An equal volume of nickel nitrate solution was impregnated into an alumina support, and then dried at 120°C for 3 hours and calcined at 250°C for 4 hours to obtain catalyst precursor A.

[0072] (2) The catalyst precursor A prepared in step (1) is impregnated with a solution containing palladium chloride, chloroplatinic acid and citric acid (5% of the carrier weight), then dried at 80°C for 5 hours and calcined at 300°C for 5 hours to obtain catalyst precursor B.

[0073] (3) Dissolve sodium aluminate and sodium hydroxide in deionized water, then add tetraethylammonium bromide, stir vigorously, slowly add silica sol, and age for 3 hours. The molar ratio of each component is n(SiO2):n(Al2O3):n(Na2O):n(tetraethylammonium bromide):n(H2O)=25:1:6:5:250 to form a precursor of type b molecular sieve. Then mix it with the catalyst precursor B prepared in step (2), and then perform hydrothermal treatment at 130℃, 1.0MPa, and pH=8.5 for 15 hours. Then filter, wash three times with deionized water, dry at 120℃ for 3 hours, calcine at 500℃ for 3 hours, and then reduce with hydrogen at a reduction temperature of 500℃, a reduction pressure of 2.5MPa, and a reduction time of 10 hours to obtain catalyst C-7.

[0074] The weight percentages of the components in catalyst C-7 are as follows: Pt 0.15%, Pd 0.12%, Ni 2.8%, b molecular sieve 3.5%, and the remainder is support.

[0075] Example 8

[0076] (1) The cobalt nitrate solution was impregnated into the alumina support in equal volume, and then dried at 100℃ for 3h and calcined at 300℃ for 4h to obtain catalyst precursor A.

[0077] (2) The catalyst precursor A prepared in step (1) is impregnated with a solution containing palladium chloride, chloroplatinic acid and citric acid (6% of the carrier weight), then dried at 90°C for 6 hours and calcined at 250°C for 5 hours to obtain catalyst precursor B.

[0078] (3) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added to deionized water, with the molar ratio of each component being n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O)=12:1:6:3:180. The mixture was stirred until a homogeneous sol was formed, which is the precursor of Y molecular sieve. It was then mixed with the catalyst precursor B prepared in step (2), and then hydrothermally treated for 10 h at 150 °C, 1.0 MPa and pH=8.0. After that, the mixture was filtered, washed three times with deionized water, dried at 110 °C for 3 h, calcined at 500 °C for 3 h, and then reduced with hydrogen at a reduction temperature of 500 °C, a reduction pressure of 3.0 MPa and a reduction time of 10 h to obtain catalyst C-8.

[0079] The weight percentages of the components in catalyst C-8 are as follows: Pt 0.11%, Pd 0.19%, Co 2.9%, Y molecular sieve 3.6%, and the remainder is the support.

[0080] Comparative Example 1

[0081] (1) Mix Y-type molecular sieve with alumina powder, nitric acid, starch and deionized water evenly, wherein the mass ratio of Y-type molecular sieve: alumina powder: nitric acid: starch: deionized water is 3.5:92:4:3:60. Then knead and extrude the mixture into strips, dry it at 80°C for 10 hours, and calcine it at 650°C for 3 hours to obtain modified alumina carrier.

[0082] (2) The modified alumina support prepared in step (1) was impregnated with a solution containing chloroplatinic acid and nickel nitrate, then dried at 110°C for 6 hours, calcined at 450°C for 5 hours, and then reduced with hydrogen at a reduction temperature of 500°C, a reduction pressure of 3.0 MPa, and a reduction time of 10 hours to obtain the comparative catalyst DC-1.

[0083] The weight percentages of each component in the comparative catalyst DC-1 are as follows: Pt 0.26%, Ni 2.8%, Y molecular sieve 3.5%, and the remainder is support.

[0084] Comparative Example 2

[0085] (1) A solution containing chloroplatinic acid and nickel nitrate was impregnated into an alumina support, then dried at 110°C for 6 hours and calcined at 450°C for 5 hours to obtain catalyst precursor A.

[0086] (2) Sodium hydroxide, silica sol, sodium aluminate and ethylenediamine were added to deionized water, with the molar ratio of each component being n(SiO2):n(Al2O3):n(Na2O):n(ethylenediamine):n(H2O)=12:1:6:3:180. The mixture was stirred until a homogeneous sol was formed, which is the precursor of Y molecular sieve. It was then mixed with the catalyst precursor B prepared in step (2), and then hydrothermally treated for 10 h at 150 °C, 1.0 MPa and pH=8.0. After that, the mixture was filtered, washed three times with deionized water, dried at 110 °C for 3 h, calcined at 500 °C for 3 h, and then reduced with hydrogen at a reduction temperature of 500 °C, a reduction pressure of 3.0 MPa and a reduction time of 10 h to obtain the comparative catalyst DC-2.

[0087] The weight percentages of each component in the comparative catalyst DC-2 are as follows: Pt 0.26%, Ni 2.8%, Y molecular sieve 3.5%, and the remainder is support.

[0088] Comparative Example 3

[0089] (1) An equal volume of nickel nitrate solution was impregnated into an alumina support, and then dried at 100°C for 3 hours and calcined at 300°C for 4 hours to obtain catalyst precursor A.

[0090] (2) The catalyst precursor A prepared in step (1) was impregnated with a solution containing chloroplatinic acid and citric acid (6% of the carrier weight), then dried at 90°C for 6 hours, calcined at 250°C for 5 hours, and then reduced with hydrogen at a reduction temperature of 500°C, a reduction pressure of 3.0 MPa, and a reduction time of 10 hours to obtain the comparative catalyst DC-3.

[0091] In contrast, the weight percentages of the components in catalyst DC-3 are 0.26% Pt, 2.8% Ni, and the remainder is the support.

[0092] The metal content and noble metal dispersion of catalysts C-1 to C-8 prepared in the above examples and catalysts DC-1 to DC-3 prepared in the comparative examples were analyzed, and the results are shown in Table 1.

[0093] Table 1.

[0094]

[0095] Example 9

[0096] This embodiment illustrates the performance of the catalyst provided by the present invention in the olefin hydrogenation reaction of reformed oil.

[0097] The evaluation feedstock was reformate oil supplied by a Sinopec refinery, with a bromine index of 3520 mgBr / 100g and a total aromatics content of 78%.

[0098] The performance of olefin hydrogenation reactions of catalysts C-1 to C-8 and comparative examples DC-1 to DC-3 was evaluated using a 200 mL fixed-bed hydrogenation apparatus.

[0099] The evaluation reaction conditions were: operating pressure 2.0 MPa, reaction temperature 180 °C, hydrogen / oil volume ratio 200:1, and volume hourly space velocity (WHSV) 10.0 h⁻¹. -1 The evaluation results are shown in Table 2.

[0100] Table 2.

[0101]

[0102] As can be seen from Table 2, the hydrogenation catalyst of the present invention has higher olefin saturation activity and selectivity.

Claims

1. A hydrogenation catalyst, characterized in that, Using alumina as a support, molecular sieves and active components are loaded onto it. The active components include noble metals and auxiliary metals. The noble metals are Pt and / or Pd, and the auxiliary metals are Ni and / or Co. By weight of the catalyst, the molecular sieves account for 1-10%, the noble metals account for 0.01-0.5% (in elemental form), and the auxiliary metals account for 0.1-5% (in elemental form). The molecular sieves are loaded on the outer surface of the catalyst. The molecular sieves are selected from at least one of Y-type molecular sieves, ZSM-5 molecular sieves, β-type molecular sieves, and MCM-41 molecular sieves. The hydrogenation catalyst is prepared by the following method: (1) The alumina support was impregnated with an impregnation solution containing auxiliary metal salts, and the catalyst precursor A was obtained by drying and calcining. (2) The catalyst precursor A is impregnated with an impregnation solution containing precious metal salts and organic additives, and then dried and calcined to obtain catalyst precursor B; the organic additives are selected from at least one of ethylene glycol, acetic acid, alcohols or organic acids with 3-10 carbon atoms. (3) The catalyst precursor B is mixed with the molecular sieve precursor and subjected to hydrothermal treatment, followed by drying and calcination to obtain the hydrogenation catalyst.

2. The catalyst according to claim 1, characterized in that, Molecular sieves account for 2-8% of the total weight of the catalyst.

3. The catalyst according to claim 2, characterized in that, Molecular sieves account for 3-5% of the total weight of the catalyst.

4. The catalyst according to claim 1, characterized in that, Based on the total weight of the catalyst, precious metals account for 0.02-0.3% in elemental form, and auxiliary metals account for 1-3% in elemental form.

5. The catalyst according to claim 1, characterized in that, The molecular sieve loaded on the outer surface of the catalyst is either loaded on a noble metal, and / or loaded on an auxiliary metal, and / or loaded on an alumina support.

6. The method for preparing the hydrogenation catalyst according to claim 1, comprising the following steps: (1) The alumina support was impregnated with an impregnation solution containing auxiliary metal salts, and the catalyst precursor A was obtained by drying and calcining. (2) The catalyst precursor A is impregnated with an impregnation solution containing precious metal salts and organic additives, and then dried and calcined to obtain catalyst precursor B; the organic additives are selected from at least one of ethylene glycol, acetic acid, alcohols or organic acids with 3-10 carbon atoms. (3) The catalyst precursor B is mixed with the molecular sieve precursor and subjected to hydrothermal treatment, followed by drying and calcination to obtain the hydrogenation catalyst.

7. The preparation method according to claim 6, characterized in that, Before use, the catalyst also undergoes a reduction process, in which precious metals and auxiliary metals are reduced to their elemental form.

8. The preparation method according to claim 6, characterized in that, The auxiliary metal salt mentioned in step (1) is a nitrate, acetate or sulfate of the auxiliary metal.

9. The preparation method according to claim 6, characterized in that, The drying conditions for step (1) are: drying temperature 60-150℃, drying time 3-6 hours; the calcination conditions for step (1) are: calcination temperature 200-300℃, calcination time 3-6 hours.

10. The preparation method according to claim 6, characterized in that, In step (2), the precious metal platinum salt is selected from at least one of chloroplatinic acid, dichlorotetraammineplatinum, ammonium chloroplatinate, platinum trichloride, platinum tetrachloride, dicarbonyl platinum dichloride, dinitrodiaminoplatinum, and sodium tetranitroplatinate, and the concentration in the solution is 0.001-0.5 g / mL based on the elemental platinum.

11. The preparation method according to claim 6, characterized in that, In step (2), the precious metal palladium salt is selected from at least one of palladium chloride, palladium nitrate, palladium acetate, sodium tetrachloropalladium, dichlorotetraamminepalladium, palladium trifluoroacetate, palladium diacetylacetonate, and palladium hexafluoroacetylacetonate, and the concentration of palladium in the solution is 0.001-0.5 g / mL.

12. The preparation method according to claim 6, characterized in that, The alcohols or organic acids having 3-10 carbon atoms are selected from at least one of glycerol, butanediol, pentanediol, citric acid, malonic acid, succinic acid, and glutaric acid.

13. The preparation method according to claim 6, characterized in that, The amount of the organic additive added is 3-10 wt% of the alumina carrier.

14. The preparation method according to claim 6, characterized in that, The drying conditions for step (2) are: drying temperature 60-100℃, drying time 3-6 hours; the calcination conditions for step (2) are: calcination temperature 200-300℃, calcination time 3-6 hours.

15. The preparation method according to claim 6, characterized in that, The molecular sieve precursor in step (3) is a silicon source or a combination of silicon and aluminum sources, which is mixed with a precipitant, a template agent and water to form a gel.

16. The preparation method according to claim 15, characterized in that, The silicon source is selected from one or more of sodium silicate, tetraethyl orthosilicate, silica sol, and silica gel for chromatography; the aluminum source is selected from one or more of sodium aluminate, aluminum hydroxide, and boehmite; the precipitant is selected from at least one of sodium hydroxide, ammonia, and potassium hydroxide; and the template agent is selected from one or more of hexadecyltrimethylammonium bromide, ethylenediamine, n-butylamine, tetrapropylammonium bromide, tetraethylammonium hydroxide, tetraethylammonium bromide, triethylamine, di-n-propylamine, diisopropylamine, and methylcellulose.

17. The preparation method according to claim 15, characterized in that, The hydrothermal treatment conditions described in step (3) are: temperature 90-200℃, pressure 0.1-2.0MPa, pH 7.5-9.0, and time 5-48 hours.

18. The preparation method according to claim 6, characterized in that, The drying conditions for step (3) are: drying temperature 90-200℃, drying time 3-6 hours; the calcination conditions for step (3) are: calcination temperature 300-500℃, calcination time 3-6 hours.

19. A hydrotreating process for reformed oil, wherein the reformed oil is reacted with the hydrotreating catalyst of claim 1.

20. The hydrotreating process for reformed oil according to claim 19, characterized in that, The reaction temperature is 130-280℃, and the pressure is 1.0-3.0 MPa; the volume ratio of hydrogen to the reformed oil is 10-1000.

Images