Hydrogenation upgrading method for light naphtha

Abstract

The invention discloses a hydrogenation upgrading method for light naphtha. The method comprises the following steps: mixing light naphtha with hydrogen, and carrying out a hydro-conversion reaction under the action of a hydro-conversion catalyst to obtain a hydrogenation reaction product; the hydro-conversion catalyst comprises ZSM-5 (Zeolite Socony Mobil)-5amp loaded with a group VIII metal; the catalyst comprises an SAPO-34 eutectic molecular sieve and macroporous alumina loaded with a group VIB metal and a group VIII metal. By adopting the method to treat the light naphtha, the proportion of C2 and C3 low-carbon alkanes in the product can be remarkably increased, so that the yield of low-carbon olefins prepared by steam cracking is increased.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization of light naphtha, specifically to a method for hydrogenating and upgrading light naphtha rich in isoalkane to produce steam cracking feedstock for low-carbon olefins. Background Technology

[0002] Ethylene and propylene, as basic chemicals, have seen their equivalent consumption increase year by year. Currently, the production of low-carbon olefins such as ethylene and propylene in the petrochemical industry is mainly achieved through light naphtha cracking. However, since the isoalkanes content in light naphtha is generally above 50%, especially in hydrocracking light naphtha where the isoalkanes proportion exceeds 70%, direct use as steam cracking feed results in poor cracking performance and low low-carbon olefin yields. Increasing the n-alkanes content in light naphtha can effectively improve the quality of feedstock for steam cracking to produce olefins, thereby increasing the yield of low-carbon olefins.

[0003] CN202110699202.X proposes a method for the ortho-articulation of light naphtha. This method involves mixing light naphtha feedstock with hydrogen and introducing the mixture from the bottom of a reactor after heating. The mixture undergoes a liquid-solid-based hydrocatalytic ortho-articulation reaction. An upflow, reaction-separation hybrid reactor is employed, combining both reaction and separation functions. This method results in high hydrocarbon ortho-articulation efficiency and significantly reduces energy consumption, operating costs, and construction costs of the ortho-articulation unit.

[0004] CN202011414744.X proposes a method and system for increasing the production of low-carbon olefins and aromatics, comprising the following steps: (1) sending light naphtha to a normal-isomeric separation unit to produce normal and non-normal components; (2) sending the non-normal components to a hydrocracking unit and separating them to obtain refinery dry gas, propane, n-butane and isobutane; the non-normal components may also be sent to an aromatization unit and separated to obtain refinery dry gas, propane, n-butane and isobutane and C5. + Components; (3) Ethylene and propylene are obtained by processing refinery dry gas, propane, n-butane and isobutane in different ways. This method can significantly improve the yield of low-carbon olefins and aromatics, improve the utilization efficiency of naphtha, and achieve rational allocation of resources.

[0005] The aforementioned methods for improving light naphtha as a steam cracking feedstock are mainly achieved through normal-isomeric separation or normalization reaction. However, normal-isomeric separation has high energy consumption and low equipment efficiency, while normalization reaction is limited by chemical equilibrium and has a low conversion rate. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for hydrogenating and upgrading light naphtha. Using this method to process light naphtha can significantly increase the proportion of low-carbon alkanes such as C2 and C3 in the product, thereby increasing the yield of low-carbon olefins produced by steam cracking.

[0007] The first aspect of the present invention provides a method for hydrogenating and upgrading light naphtha, the method comprising: mixing light naphtha with hydrogen gas, and subjecting the mixture to a hydrogenation conversion reaction under the action of a hydrogenation conversion catalyst to obtain a hydrogenation reaction product; wherein the hydrogenation conversion catalyst comprises a ZSM-5 & SAPO-34 eutectic molecular sieve supported on a Group VIII metal and macroporous alumina supported on a Group VIB metal and a Group VIII metal.

[0008] In the method of this invention, in the ZSM-5 & SAPO-34 eutectic molecular sieve loaded with Group VIII metals, a solution containing a Group VIII metal amine complex is used as the impregnation solution to load the eutectic molecular sieve. Furthermore, the Group VIB and Group VIII metals are loaded onto macroporous alumina using a conventional impregnation method, preferably a supersaturated impregnation method.

[0009] In the method of this invention, Group VIII metals and Group VIB metals exist in the catalyst in the form of oxides.

[0010] In the method of this invention, the light naphtha is selected from at least one of straight-run light naphtha and hydrocracked light naphtha; the initial boiling point of the light naphtha is 15-30°C, and the final boiling point is 60-90°C. The mass content of C5-C6 isoalkanes in the light naphtha is 30%-100%, preferably 50%-90%.

[0011] In the method of this invention, the hydroconversion reaction conditions are as follows: reaction pressure is 1.0–8.0 MPa, reaction temperature is 350–550 °C, hydrogen-to-oil volume ratio is 50:1–2000:1, and liquid hourly space velocity is 0.2–10.0 h⁻¹. -1 Preferably, the reaction pressure is 2.0–6.0 MPa, the reaction temperature is 400–500 °C, the hydrogen-to-oil volume ratio is 100:1–1000:1, and the liquid hourly space velocity is 0.5–5.0 h⁻¹. -1 .

[0012] In the method of this invention, the specific surface area of ​​the hydroconversion catalyst is 200–400 m². 2 / g, with a pore volume of 0.20~0.40mL / g.

[0013] In the method of the present invention, the hydroconversion catalyst, based on the weight of the catalyst, contains 1.0% to 6.0% (preferably 2.0% to 6.0%) of Group VIII metals (based on oxides), 2.0% to 24.0% (preferably 6.5% to 22.0%) of Group VIB metals (based on oxides), 20.0% to 60.0% (preferably 21.0% to 56.0%) of macroporous alumina, and 15.0% to 70.0% of ZSM-5 & SAPO-34 eutectic molecular sieve. Further, in the hydroconversion catalyst, the Group VIB metals are preferably molybdenum and / or tungsten, and the Group VIII metals are preferably cobalt and / or nickel.

[0014] In the method of this invention, the macroporous alumina in the hydroconversion catalyst has the following properties: pore volume of 0.7–1.0 mL / g and specific surface area of ​​200–500 m² / g. 2 / g. The pore volume of the ZSM-5 & SAPO-34 eutectic molecular sieve is 0.23–0.26 cm³. 3 / g, specific surface area of ​​500-560m² 2 / g, the silicon-aluminum molar ratio SiO2:Al2O3 is 1.5~4.0.

[0015] In the method of this invention, M is a hydrogenation conversion catalyst. x / M y The value is 1.30 to 2.80, preferably 1.50 to 2.50, wherein M x M represents the molar ratio of Group VIII metal atoms to Group VIB metal atoms in the bulk catalyst phase. y This represents the molar ratio of Group VIII metal atoms to Group VIB metal atoms on the catalyst surface. Further, the molar ratio of Group VIII metal atoms to Group VIB metal atoms in the bulk catalyst phase refers to the molar ratio of Group VIII metal atoms to Group VIB metal atoms in the overall catalyst.

[0016] In the method of the present invention, the ZSM-5 molecular sieve has a mass content of 20% to 50% and the SAPO-34 molecular sieve has a mass content of 50% to 80%.

[0017] In the method of the present invention, M in the catalyst x M was determined by X-ray fluorescence spectroscopy. y X-ray photoelectron spectroscopy was used for analysis.

[0018] The method of the present invention includes the following steps for preparing the hydroconversion catalyst:

[0019] (1) A solution containing a group VIII metal amine complex was mixed with ZSM-5 & SAPO-34 eutectic molecular sieve, impregnated in a sealed environment, and then calcined to obtain ZSM-5 & SAPO-34 eutectic molecular sieve loaded with group VIII metal.

[0020] (2) Macroporous alumina was impregnated with an aqueous solution containing Group VIB metals and Group VIII metals and then calcined to obtain macroporous alumina loaded with Group VIB metals and Group VIII metals.

[0021] (3) Mix ZSM-5 & SAPO-34 eutectic molecular sieve loaded with Group VIII metals and macroporous alumina loaded with Group VIB and Group VIII metals, shape and calcine to obtain a hydroconversion catalyst.

[0022] Further, the preparation process of the solution containing the Group VIII metal amine complex in step (1) includes: dissolving the Group VIII metal salt in deionized water, stirring until homogeneous, and then adding inorganic ammonium and / or organic amine dropwise to the solution until the pH value of the solution is 7-8. Further, the Group VIII metal in the Group VIII metal salt is preferably cobalt and / or nickel; the Group VIII metal salt is preferably a nitrate. The inorganic ammonium is selected from one or more of ammonia water (preferably, the mass concentration of ammonia water is 20%-30%) and ammonium chloride; the organic amine is selected from one or more of ethylamine, isopropylamine, and diethylamine. Further, the content of the Group VIII metal in the solution containing the Group VIII metal amine complex, calculated as oxide, is 1-15 g / 100 mL.

[0023] Furthermore, the ZSM-5 & SAPO-34 eutectic molecular sieve described in step (1) can be prepared using the following steps:

[0024] (a) Mix silicon source, aluminum source, phosphorus source, template agent and water, and crystallize to obtain SAPO-34 molecular sieve;

[0025] (b) Prepare a mixed slurry of silicon source, aluminum source, template agent and water, mix the SAPO-34 molecular sieve obtained in step (a) with the mixed slurry, crystallize and calcine to obtain hydrogen-form ZSM-5&SAPO-34 eutectic molecular sieve.

[0026] Further, in step (a), the molar ratio of silicon source, aluminum source, phosphorus source, template agent, and water is (0.2–1.0) SiO2 : 1.0 Al2O3 : (0.9–1.2) P2O5 : (0.5–8) R (template agent) : (10–200) H2O. The crystallization conditions are as follows: crystallization at 180–200°C for 3–5 days.

[0027] Further, in step (b), the molar ratio of silicon source, aluminum source, template agent, and water is 1.0SiO2:(0.005~0.1)Al2O3:(0.5~6.0)R (template agent):(10~200)H2O. The crystallization conditions are as follows: crystallization at 180~200℃ for 2~3 days. Further, after crystallization in step (b), the product undergoes conventional washing, filtration, and drying steps, followed by calcination to obtain the hydrogen-form ZSM-5&SAPO-34 eutectic molecular sieve. For example, the product is washed with deionized water until the pH value is 7~8. The drying conditions are as follows: drying at 100~120℃ for 3~6 hours. The calcination conditions are as follows: calcination at 500~600℃ for 4~8 hours.

[0028] Furthermore, the amount of SAPO-34 molecular sieve added is 100% to 300% of the mass of silicon source (as SiO2) in the mixed slurry.

[0029] Furthermore, the pore volume of the ZSM-5 & SAPO-34 eutectic molecular sieve is 0.23–0.26 cm³. 3 / g, specific surface area of ​​500-560m² 2 / g, the silicon-aluminum molar ratio SiO2:Al2O3 is 1.5~4.0.

[0030] Furthermore, in the preparation process of the ZSM-5 & SAPO-34 eutectic molecular sieve, the silicon source is selected from one or more of silica sol, silica, tetraethyl orthosilicate, etc.; the aluminum source is selected from one or more of aluminum sulfate octadecyl water, aluminum isopropoxide, boehmite, etc.; the phosphorus source is phosphoric acid; the template agent is selected from one or more of isopropylamine, triethylamine, tetraethylammonium hydroxide, etc., which can simultaneously guide the generation of both SAPO-34 and ZSM-5 molecular sieves; and the water is deionized water.

[0031] Further, the closed impregnation process in step (1) is as follows: ZSM-5 & SAPO-34 eutectic molecular sieve is mixed with a solution containing a Group VIII metal amine complex and placed in a closed reaction vessel. Then, the mixture is heated to 100–120°C and subjected to autogenous pressure for 2–4 hours of stirring and impregnation, with a stirring speed of 100–400 rpm. Further, the solid-liquid volume ratio of ZSM-5 & SAPO-34 eutectic molecular sieve and the solution containing a Group VIII metal amine complex is 1:2 to 1:5.

[0032] Further, after impregnation in step (1), the material is filtered and dried in a conventional manner, and then calcined to obtain ZSM-5 & SAPO-34 eutectic molecular sieve loaded with Group VIII metals. For example, the drying temperature is 100-150℃ and the drying time is 1-12h; the calcination temperature is 450-550℃ and the calcination time is 3-6h.

[0033] Further, in the aqueous solution containing Group VIB and Group VIII metals in step (2), the Group VIB metal source is one or more of tungsten salts (such as ammonium metatungstate) or molybdenum salts (such as ammonium molybdate), and the Group VIII metal source is one or more of nickel salts (such as nickel nitrate) or cobalt salts (such as cobalt nitrate). Further, the content of the Group VIB metal in the solution, calculated as oxides, is 10–50 g / 100 mL, and the content of the Group VIII metal, calculated as oxides, is 1–10 g / 100 mL.

[0034] Further, in step (2), the impregnation is supersaturated, and the solid-liquid volume ratio of the macroporous alumina to the aqueous solution containing Group VIB and Group VIII metals is 1:2 to 1:5. Further, the macroporous alumina has a pore volume of 0.7 to 1.0 mL / g and a specific surface area of ​​200 to 500 m². 2 / g.

[0035] Further, after impregnation in step (2), the alumina is filtered and dried in a conventional manner, and then calcined to obtain macroporous alumina loaded with Group VIB and Group VIII metals. For example, the drying temperature is 100-150℃ and the drying time is 1-12h; the calcination temperature is 450-550℃ and the calcination time is 3-6h.

[0036] Further, in step (3), the molding can be carried out using conventional methods in the art, such as extrusion molding. Molding aids can be added during the molding process, such as at least one of extrusion aids and pectinic acids, preferably pectinic acids; the extrusion aid can be guar gum powder; the pectinic acid can be at least one of citric acid, acetic acid, and nitric acid, preferably at least one of citric acid and nitric acid. Further, the amount of pectinic acid added is less than 2% of the sum of the mass of the ZSM-5 & SAPO-34 eutectic molecular sieve loaded with Group VIII metals and the macroporous alumina loaded with Group VIB and Group VIII metals, and the amount of extrusion aid added is less than 3% of the sum of the mass of the ZSM-5 & SAPO-34 eutectic molecular sieve loaded with Group VIII metals and the macroporous alumina loaded with Group VIB and Group VIII metals.

[0037] Further, in step (3), after the molding and drying process, the catalyst is calcined to obtain the catalyst. The drying temperature is 100℃~150℃, and the drying time is 2~4h; the calcination temperature is 400℃~600℃, and the calcination time is 3~5h.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] Light naphtha mainly consists of short-chain alkanes such as C5 and C6. In the process of hydrogenation to produce small molecule hydrocarbons such as C2 and C3, the adsorption and dehydrogenation of alkanes are difficult to carry out. As the controlling step of the overall reaction, strengthening the adsorption capacity of alkanes on acidic sites and improving the dehydrogenation capacity of the catalyst are beneficial to the hydrogenation conversion of light naphtha.

[0040] In the catalyst preparation process of this invention, a group III metal amine complex solution is used to impregnate the molecular sieve under self-generated pressure. The basic groups of the metal amine complex selectively adsorb and bind to the acidic sites within the molecular sieve pores. This results in a more uniform dispersion of the group III metal active particles with stronger dehydrogenation activity and a significantly shorter distance between the metal active sites and the acidic sites of the molecular sieve. This enhances the adsorption of light naphtha molecules at the acidic sites, increasing the dehydrogenation rate of the reactants. After dehydrogenation, the olefin products rapidly generate carbocations under the influence of the acidic sites, promoting the cracking of light naphtha molecules. Impregnation of macroporous alumina with a mixed aqueous solution of group VIB and VIII metal salts allows for the selective adsorption of bimetallic active sites with stronger hydrogenation activity within the macroporous alumina. This enables the small-molecule olefins obtained from the cracking of light hydrocarbons to rapidly saturate after diffusing out of the molecular sieve pores, thus improving catalytic activity.

[0041] In the method of this invention, the acidic centers of the hydroconversion catalyst are ZSM-5 & SAPO-34 eutectic molecular sieves. Compared with the simple mechanical mixing of the two molecular sieves, the acidic centers of the eutectic molecular sieve are more uniformly distributed, which fully leverages the high acid strength cracking function of ZSM-5 molecular sieve and the pore confinement synergistic catalytic function of SAPO-34 molecular sieve, effectively improving the selectivity of C2 and C3 low-carbon products.

[0042] In the method of this invention, light naphtha is converted into a mixed product containing a high proportion of ethane and propane, which is used as a feedstock for steam cracking and can effectively improve the yield of low-carbon olefins. Attached Figure Description

[0043] Figure 1 The XRD patterns are of the ZSM-5 & SAPO-34 eutectic molecular sieve obtained in Example 1, the ZSM-5 molecular sieve obtained in Comparative Example 4, and the SAPO-34 molecular sieve obtained in Comparative Example 4.

[0044] Figure 2 This is a schematic diagram of the process flow of the embodiments and comparative examples of the present invention;

[0045] Explanation of key figure labels:

[0046] 1-Light naphtha, 2-Hydrogen, 3-Hydroconversion reaction zone, 4-Hydroconversion catalyst, 5-Hydroconversion product, 6-Separation system, 7-Hydrogen-rich gas in gas phase, 8-Liquid phase. Detailed Implementation

[0047] The following examples and comparative examples further illustrate the role and effect of the technical solution of the present invention, but the following examples do not constitute a limitation on the scope of protection of the present invention.

[0048] In this invention, the molar ratio of Group VIII metal atoms to Group VIB metal atoms in the bulk catalyst phase was obtained by X-ray fluorescence spectroscopy (XRF) analysis. A ZSX100e X-ray fluorescence spectrometer was used, with the spectral line being Kα, the crystal being LiF1, the target material being Rh, the detector being SC scintillation, the timing being 20s, and the optical path atmosphere being vacuum.

[0049] In this invention, the molar ratio of Group VIII metal atoms to Group VIB metal atoms on the catalyst surface was determined by X-ray photoelectron spectroscopy (XPS). The elemental composition and state of the catalyst surface (3 nm to 10 nm) were determined using a Thermofisher Multilab 2000 electron spectrometer. The excitation source was Mg Kα, and the cathode voltage and current were 13 kV and 20 mA, respectively. The electron binding energy was calibrated using C1s (284.6 eV).

[0050] In this invention, unless otherwise specified, all percentages (%) in the embodiments and comparative examples refer to mass fractions.

[0051] The properties of the ZSM-5 & SAPO-34 eutectic molecular sieve prepared in this invention are shown in Table 1. The macroporous alumina is a commercially available product with a pore volume of 1.0 cm³. 3 / g, specific surface area is 400m² 2 / g.

[0052] In this invention, the conversion rate, product yield, and selectivity of light naphtha are calculated as follows:

[0053] Conversion rate = (mass of C5 and C6 hydrocarbons in feedstock - mass of C5 and C6 hydrocarbons in product) / (mass of C5 and C6 hydrocarbons in feedstock) × 100%;

[0054] C2+C3 yield = (mass of C2 and C3 in the product / total mass of the product) × 100%;

[0055] C2+C3 selectivity = (C2+C3 yield) / conversion rate × 100%;

[0056] C5, C6, C2, and C3 refer to pentane, hexane, ethane, and propane, respectively.

[0057] Example 1

[0058] 230.6 g of phosphoric acid (H3PO4 mass fraction of 85%) was weighed and dissolved in 774.0 g of deionized water. During stirring, 139.7 g of boehmite (Al2O3 mass fraction of 73%), 303.0 g of triethylamine (TEA), and 90.0 g of silica sol (SiO2 mass fraction of 40%) were added sequentially to form a mixed gel with a ratio of 0.6SiO2:1Al2O3:1P2O5:3TEA:50H2O. The uniformly mixed initial gel was placed in a sealed reactor and crystallized at 200℃ for 3 days. The resulting mixture was washed until the pH value was 7, then filtered and dried at 120℃ for 4 hours to obtain SAPO-34 molecular sieve. 7.0 g of pseudoboehmite (Al2O3 mass fraction 73%) was weighed and added to 450.0 g of deionized water. During stirring, 151.5 g of triethylamine (TEA) and 150.0 g of silica sol (SiO2 mass fraction 40%) were added sequentially to form a mixed gel of SiO2:0.05Al2O3:1.5TEA:30H2O. 90 g of the prepared SAPO-34 molecular sieve was mixed evenly with the mixed gel and placed in a sealed reactor for crystallization at 180℃ for 2 days. The resulting mixture was then washed until the pH value reached 7, filtered, dried at 120℃ for 4 hours, and calcined at 550℃ for 6 hours to obtain the hydrogen-form ZSM-5&SAPO-34 eutectic molecular sieve, denoted as Z&S-1. In Z&S-1, the mass content of ZSM-5 molecular sieve was 39.5%, and the mass content of SAPO-34 molecular sieve was 60.5%.

[0059] 40g of nickel nitrate (NiO mass fraction 25%) was dissolved in deionized water, stirred evenly, and then ammonia water (mass concentration 20%) was added to adjust the pH of the solution to 7.0. The solution was then brought to a final volume of 1000mL to obtain a nickel-amine complex solution with a nickel content (calculated as oxides) of 1.0g / 100mL. 100g of Z&S-1 molecular sieve was mixed with 200mL of the above nickel-amine complex solution, placed in a reaction vessel, sealed, and stirred at 150rpm. The mixture was heated to 100℃ and held at that temperature for 3 hours. After quenching and cooling, the mixture was filtered, dried at 120℃ for 6 hours, and calcined at 550℃ for 4 hours to obtain material I, denoted as N-1.

[0060] Take 150g of macroporous alumina and immerse it in 300ml of an aqueous solution with a nickel content (calculated as oxide) of 4.0g / 100mL and a tungsten content (calculated as oxide) of 10.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, denoted as NW-1.

[0061] Take 100g of N-1 and 100g of NW-1, mix them, and put them into a rolling mill for grinding. Add 80g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain catalyst CAT-1, the properties of which are shown in Table 1.

[0062] Example 2

[0063] The preparation process of the eutectic molecular sieve Z&S in this embodiment is the same as in Example 1.

[0064] 400g of nickel nitrate (NiO mass fraction of 25%) was dissolved in deionized water, stirred evenly, and then isopropylamine was added to adjust the pH of the solution to 8.0. The solution was then brought to a final volume of 1000mL to obtain a nickel-amine complex solution with a nickel content (calculated as oxides) of 10g / 100mL. 100g of Z&S-1 molecular sieve was mixed with 200mL of the above nickel-amine complex solution and placed in a reaction vessel. The vessel was sealed and stirred at 300rpm. The temperature was raised to 110℃ and held for 3 hours. The mixture was then quenched and cooled, filtered, dried at 120℃ for 6 hours, and calcined at 550℃ for 4 hours to obtain material I, denoted as N-2.

[0065] Take 150g of macroporous alumina and immerse it in 300mL of an aqueous solution with a nickel content (calculated as oxide) of 4.0g / 100mL and a tungsten content (calculated as oxide) of 20.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, denoted as NW-2.

[0066] Take 100g of N-2 and 80g of NW-2, mix them, and put them into a rolling mill for grinding. Add 72g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain catalyst CAT-2, the properties of which are shown in Table 1.

[0067] Comparative Example 1

[0068] The preparation process of the eutectic molecular sieve Z&S in this comparative example is the same as that in Example 1.

[0069] 100g of Z&S-1 molecular sieve and 100g of macroporous alumina were impregnated in 400mL of an aqueous solution with a nickel content (calculated as oxide) of 5.0g / 100mL and a tungsten content (calculated as oxide) of 10.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h, and calcination at 550℃ for 4h, the resulting material was denoted as DNW-1. DNW-1 was then mixed and milled in a mill, and 80g of dilute nitric acid solution (HNO3 mass fraction of 4%) was added. The mixture was milled into a paste, extruded into strips, dried at 120℃ for 6h, and then calcined at 550℃ for 4h to obtain the comparative catalyst DCAT-1, the properties of which are shown in Table 1.

[0070] Comparative Example 2

[0071] The preparation process of the eutectic molecular sieve Z&S in this comparative example is the same as that in Example 1.

[0072] 560g of nickel nitrate (NiO mass fraction of 25%) was dissolved in deionized water, stirred evenly, and then isopropylamine was added to adjust the pH of the solution to 8.0. The solution was then brought to a final volume of 1000mL to obtain a nickel-amine complex solution with a nickel content (calculated as oxides) of 14g / 100mL. 100g of Z&S-1 molecular sieve was mixed with 200mL of the above nickel-amine complex solution and placed in a reaction vessel. The vessel was sealed and stirred at 300rpm. The temperature was raised to 110℃ and held for 3 hours. The mixture was then quenched and cooled, filtered, dried at 120℃ for 6 hours, and calcined at 550℃ for 4 hours. The resulting material was designated DN-2.

[0073] Take 150g of macroporous alumina and soak it in 300mL of an aqueous solution with a tungsten content (calculated as oxide) of 20.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, which is denoted as DW-2.

[0074] Take 100g of DN-2 and 80g of DW-2, mix them, and put them into a rolling mill for grinding. Add 72g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain the comparative catalyst DCAT-2, the properties of which are shown in Table 1.

[0075] Comparative Example 3

[0076] The preparation process of the eutectic molecular sieve Z&S in this comparative example is the same as that in Example 1.

[0077] 40g of nickel nitrate (NiO mass fraction of 25%) was dissolved in deionized water and diluted to 1000mL to obtain a nickel salt aqueous solution with a nickel content (calculated as oxide) of 1.0g / 100mL. 100g of Z&S-1 molecular sieve was mixed with 200mL of the above nickel salt solution and placed in a reaction vessel. After sealing, the mixture was stirred at 150rpm and heated to 100℃, held at that temperature for 3h, then quenched and cooled. After filtration, drying at 120℃ for 6h, and calcining at 550℃ for 4h, material I was obtained, denoted as DN-3.

[0078] Take 150g of macroporous alumina and soak it in 300ml of an aqueous solution with a nickel content (calculated as oxide) of 4.0g / 100mL and a tungsten content (calculated as oxide) of 10.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, which is denoted as DNW-3.

[0079] Take 100g of DN-3 and 100g of DNW-3, mix them, and put them into a rolling mill for grinding. Add 80g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain catalyst DCAT-3, the properties of which are shown in Table 1.

[0080] Comparative Example 4

[0081] Preparation of ZSM-5 molecular sieve:

[0082] 7.0 g of pseudoboehmite (Al2O3 mass fraction 73%) was weighed and added to 450.0 g of deionized water. During stirring, 151.5 g of triethylamine (TEA) and 150.0 g of silica sol (SiO2 mass fraction 40%) were added sequentially to form a mixed gel of SiO2:0.05Al2O3:1.5TEA:30H2O. The mixed gel was placed in a sealed reactor and crystallized at 180℃ for 2 days. The resulting mixture was then washed until the pH reached 7, filtered, dried at 120℃ for 4 hours, and calcined at 550℃ for 6 hours to obtain the hydrogen-form ZSM-5 molecular sieve. Its XRD pattern is shown below. Figure 1 As shown.

[0083] Preparation of SAPO-34 molecular sieve:

[0084] 230.6 g of phosphoric acid (H3PO4 mass fraction 85%) was dissolved in 774.0 g of deionized water. During stirring, 139.7 g of boehmite (Al2O3 mass fraction 73%), 303.0 g of triethylamine (TEA), and 90.0 g of silica sol (SiO2 mass fraction 40%) were added sequentially to form a mixed gel with a composition of 0.6SiO2:1Al2O3:1P2O5:3TEA:50H2O. The mixed gel was placed in a sealed reactor and crystallized at 200℃ for 3 days. The resulting mixture was washed until the pH reached 7, then filtered, dried at 120℃ for 4 hours, and calcined at 550℃ for 6 hours to obtain the hydrogen-form SAPO-34 molecular sieve. Its XRD pattern is shown below. Figure 1 As shown.

[0085] 40g of nickel nitrate (NiO mass fraction of 25%) was dissolved in deionized water, stirred evenly, and then ammonia water (mass concentration of 20%) was added to adjust the pH of the solution to 7.0. The solution was then brought to a final volume of 1000mL to obtain a nickel-amine complex solution with a nickel content (calculated as oxides) of 1.0g / 100mL. 40g of the above ZSM-5 molecular sieve and 60g of the above SAPO-34 molecular sieve were mixed with 200mL of the above nickel-amine complex solution and placed in a reaction vessel. After sealing, the mixture was stirred at 150rpm, heated to 100℃, and held at that temperature for 3h. The mixture was then quenched and cooled, filtered, dried at 120℃ for 6h, and calcined at 550℃ for 4h to obtain material I, denoted as DN-4.

[0086] Take 150g of macroporous alumina and immerse it in 300mL of an aqueous solution with a nickel content (calculated as oxide) of 4.0g / 100mL and a tungsten content (calculated as oxide) of 10.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, which is denoted as DNW-4.

[0087] Take 100g of DN-4 and 100g of DNW-4, mix them, and put them into a rolling mill for grinding. Add 80g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain catalyst DCAT-4, the properties of which are shown in Table 1.

[0088] Example 3

[0089] The preparation process of the eutectic molecular sieve Z&S in this embodiment is the same as in Example 1.

[0090] 240g of cobalt nitrate (CoO mass fraction 25%) was dissolved in deionized water, stirred evenly, and then ammonia water (mass fraction 20%) was added to adjust the pH of the solution to 7.5. The solution was then brought to a final volume of 1000mL to obtain a cobalt-amine complex solution with a cobalt content (calculated as oxides) of 8g / 100mL. 100g of Z&S-1 molecular sieve was mixed with 200mL of the above cobalt-amine complex solution and placed in a reaction vessel. The vessel was sealed and stirred at 250rpm. The temperature was raised to 120℃ and held for 4 hours. The mixture was then quenched and cooled, filtered, dried at 120℃ for 6 hours, and calcined at 550℃ for 4 hours to obtain material I, denoted as C-3.

[0091] Take 150g of macroporous alumina and soak it in 300mL of an aqueous solution with a cobalt content (calculated as oxide) of 6g / 100mL and a molybdenum content (calculated as oxide) of 30g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, which is denoted as CM-3.

[0092] Take 100g of C-3 and 150g of CM-3, mix them, and put them into a rolling mill for grinding. Add 100g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain catalyst CAT-3, the properties of which are shown in Table 1.

[0093] Example 4

[0094] The preparation process of the eutectic molecular sieve Z&S in this embodiment is the same as in Example 1.

[0095] 160g of nickel nitrate (NiO mass fraction of 25%) was dissolved in deionized water, stirred evenly, and then isopropylamine was added to adjust the pH of the solution to 7.0. The solution was then brought to a final volume of 1000mL to obtain a nickel-amine complex solution with a nickel content (calculated as oxides) of 7g / 100mL. 100g of Z&S-1 molecular sieve was mixed with 200mL of the above nickel-amine complex solution and placed in a reaction vessel. After sealing, the mixture was stirred at 300rpm and heated to 110℃, held at that temperature for 4h, then quenched and cooled. After filtration, drying at 120℃ for 6h, and calcining at 550℃ for 4h, material I was obtained, denoted as N-4.

[0096] Take 200g of macroporous alumina and immerse it in 400mL of an aqueous solution with a nickel content (calculated as oxide) of 7g / 100mL and a molybdenum content (calculated as oxide) of 40g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, denoted as NM-4.

[0097] Take 100g of N-4 and 200g of NM-4, mix them, and put them into a rolling mill for grinding. Add 120g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain CAT-4, the properties of which are shown in Table 1.

[0098] Example 5

[0099] The preparation process of the eutectic molecular sieve Z&S in this embodiment is the same as in Example 1.

[0100] 180g of cobalt nitrate (CoO mass fraction 25%) was dissolved in deionized water, stirred evenly, and then isopropylamine was added to adjust the pH of the solution to 8.0. The solution was then brought to a final volume of 1000mL to obtain a cobalt-amine complex solution with a cobalt content (calculated as oxides) of 6g / 100mL. 100g of Z&S-1 molecular sieve was mixed with 200mL of the above cobalt-amine complex solution and placed in a reaction vessel. After sealing, the mixture was stirred at 350rpm and heated to 120℃, held at that temperature for 4h, then quenched and cooled. After filtration, drying at 120℃ for 6h, and calcining at 550℃ for 4h, material I was obtained, denoted as C-5.

[0101] Take 150g of macroporous alumina and soak it in 300mL of an aqueous solution with a cobalt content (calculated as oxide) of 8g / 100mL and a tungsten content (calculated as oxide) of 40.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, which is denoted as CW-5.

[0102] Take 100g of C-5 and 60g of CW-5, mix them, and put them into a rolling mill for grinding. Add 64g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain catalyst CAT-5, the properties of which are shown in Table 1.

[0103] Example 6

[0104] The preparation process of the eutectic molecular sieve Z&S in this embodiment is the same as in Example 1.

[0105] 320g of nickel nitrate (NiO mass fraction 25%) was dissolved in deionized water, stirred evenly, and then ammonia water (mass fraction 20%) was added to adjust the pH of the solution to 7.0. The solution was then brought to a final volume of 1000mL to obtain a nickel-amine complex solution with a nickel content (calculated as oxides) of 4.0g / 100mL. 100g of Z&S-1 molecular sieve was mixed with 200mL of the above nickel-amine complex solution and placed in a reaction vessel. After sealing, the mixture was stirred at 250rpm and heated to 120℃, held at that temperature for 4h, then quenched and cooled. After filtration, drying at 120℃ for 6h, and calcining at 550℃ for 4h, material I was obtained, denoted as N-6.

[0106] Take 150g of macroporous alumina and immerse it in 300mL of an aqueous solution with a nickel content (calculated as oxide) of 4.0g / 100mL and a tungsten content (calculated as oxide) of 30.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, material II is obtained, which is denoted as NW-6.

[0107] Take 100g of N-6 and 40g of NW-6, mix them, and put them into a rolling mill for grinding. Add 56g of dilute nitric acid solution (HNO3 mass fraction of 4%), grind into a paste, extrude into strips, dry the extruded strips at 120℃ for 6h, and then calcine at 550℃ for 4h to obtain catalyst CAT-6, the properties of which are shown in Table 1.

[0108] Example 7

[0109] The preparation process of the eutectic molecular sieve Z&S-2 in this embodiment is as follows:

[0110] 230.6 g of phosphoric acid (H3PO4 mass fraction of 85%) was weighed and dissolved in 774.0 g of deionized water. During stirring, 139.7 g of boehmite (Al2O3 mass fraction of 73%), 303.0 g of triethylamine (TEA), and 90.0 g of silica sol (SiO2 mass fraction of 40%) were added sequentially to form a mixed gel with a ratio of 0.6SiO2:1Al2O3:1P2O5:3TEA:50H2O. The uniformly mixed initial gel was placed in a sealed reactor and crystallized at 200℃ for 3 days. The resulting mixture was washed until the pH value was 7, then filtered and dried at 120℃ for 4 hours to obtain SAPO-34 molecular sieve. 7.0 g of pseudoboehmite (73% Al2O3 by mass) was weighed and added to 450.0 g of deionized water. During stirring, 151.5 g of triethylamine (TEA) and 150.0 g of silica sol (40% SiO2 by mass) were added sequentially to form a mixed gel of SiO2:0.05Al2O3:1.5TEA:30H2O. 60 g of the prepared SAPO-34 molecular sieve was mixed evenly with the mixed gel and placed in a sealed reactor for crystallization at 180℃ for 2 days. The resulting mixture was then washed until the pH reached 7, filtered, dried at 120℃ for 4 hours, and calcined at 550℃ for 6 hours to obtain the hydrogen-form ZSM-5&SAPO-34 eutectic molecular sieve, denoted as Z&S-2. In Z&S-2, the mass content of ZSM-5 molecular sieve was 48.7%, and the mass content of SAPO-34 molecular sieve was 51.3%.

[0111] The catalyst preparation method in this embodiment is the same as in Example 3, except that 100g of Z&S-1 molecular sieve is replaced with an equal amount of Z&S-2 molecular sieve to obtain catalyst CAT-7, the properties of which are shown in Table 1.

[0112] Example 8

[0113] The preparation process of the eutectic molecular sieve Z&S-3 in this embodiment is as follows:

[0114] 1153.0g of phosphoric acid (H3PO4 mass fraction of 85%) was weighed and dissolved in 3870.0g of deionized water. During stirring, 698.5g of boehmite (Al2O3 mass fraction of 73%), 1515.0g of triethylamine (TEA), and 450.0g of silica sol (SiO2 mass fraction of 40%) were added sequentially to form a mixed gel with a ratio of 0.6SiO2:1Al2O3:1P2O5:3TEA:50H2O. The uniformly mixed initial gel was placed in a sealed reactor and crystallized at 200℃ for 3 days. The resulting mixture was washed until the pH value was 7, then filtered and dried at 120℃ for 4 hours to obtain SAPO-34 molecular sieve. 7.0 g of boehmite (73% Al2O3 by mass) was weighed and added to 450.0 g of deionized water. During stirring, 151.5 g of triethylamine (TEA) and 150.0 g of silica sol (40% SiO2 by mass) were added sequentially to form a mixed gel of SiO2:0.05Al2O3:1.5TEA:30H2O. 180 g of the prepared SAPO-34 molecular sieve was mixed evenly with the mixed gel and placed in a sealed reactor for crystallization at 180℃ for 2 days. The resulting mixture was then washed until the pH reached 7, filtered, dried at 120℃ for 4 hours, and calcined at 550℃ for 6 hours to obtain the hydrogen-form ZSM-5&SAPO-34 eutectic molecular sieve, denoted as Z&S-3. In Z&S-3, the mass content of ZSM-5 molecular sieve was 22.8%, and the mass content of SAPO-34 molecular sieve was 77.2%.

[0115] The catalyst preparation method in this embodiment is the same as in Example 3, except that 100g of Z&S-1 molecular sieve is replaced with an equal amount of Z&S-3 molecular sieve to obtain catalyst CAT-8, the properties of which are shown in Table 1.

[0116] Table 1. Composition and properties of the catalysts obtained in each example.

[0117]

[0118] Continued in Table 1: Composition and properties of the catalysts obtained in each example

[0119]

[0120]

[0121] Example 9

[0122] This embodiment describes the evaluation method and results of the present invention. Catalysts CAT-1 to CAT-8 and DCAT-1 to DCAT-4 were evaluated in a fixed-bed hydrogenation test apparatus under the same process conditions: reaction pressure 4.0 MPa, hydrogen-to-oil volume ratio 600:1, and volume hourly space velocity 1.0 h⁻¹. 1 The reaction temperature was 420℃ for the conversion of light naphtha. The feedstock used for evaluation was hydrocracked light naphtha, and its properties are shown in Table 2. The evaluation results are shown in Tables 3 and 4.

[0123] Table 2 Composition and Properties of Light Naphtha Feedstock

[0124] Hydrocarbon composition, % <![CDATA[i-C4 (isobutane)]]> 1.5 <![CDATA[n-C4 (n-butane)]]> 3.7 <![CDATA[i-C5 (isopentane)]]> 52.0 <![CDATA[n-C5 (n-pentane)]]> 12.4 <![CDATA[i-C6 (isopentane)]]> 28.8 <![CDATA[n-C6 (n-hexane)]]> 1.6 Initial boiling point, ℃ 24 Final boiling point, ℃ 63

[0125] Table 3. Conversion results of the catalysts in the examples.

[0126] Catalyst number CAT-1 CAT-2 CAT-3 CAT-4 CAT-5 CAT-6 CAT-7 CAT-8 Conversion rate, % 69.4 72.7 75.6 78.3 79.5 77.5 75.1 77.8 <![CDATA[Yield of C2 + C3, %]]> 50.4 54.6 58.1 60.5 61.8 59.7 58.0 60.2 <![CDATA[C2 + C3 selectivity, %]]> 72.6 75.1 76.9 77.3 77.7 77.0 77.2 77.4

[0127] Table 4. Conversion results of the comparative example catalysts

[0128] Catalyst number DCAT-1 DCAT-2 DCAT-3 DCAT-4 Conversion rate, % 42.2 39.5 52.4 67.8 <![CDATA[Yield of C2 + C3, %]]> 24.1 25.4 36.3 48.7 <![CDATA[C2 + C3 selectivity, %]]> 57.1 64.3 69.3 71.8

[0129] The specific embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combining the various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for hydrogenating and upgrading light naphtha, the method comprising: Light naphtha is mixed with hydrogen and undergoes a hydroconversion reaction in the presence of a hydroconversion catalyst to obtain the hydroconversion product. The hydroconversion catalyst comprises ZSM-5 & SAPO-34 eutectic molecular sieves supported on Group VIII metals and macroporous alumina supported on Group VIB and Group VIII metals.

2. The method according to claim 1, characterized in that: In the ZSM-5 & SAPO-34 eutectic molecular sieve loaded with Group VIII metals, a solution containing a Group VIII metal amine complex is used as the impregnation solution to load the eutectic molecular sieve.

3. The method according to claim 1, characterized in that: The light naphtha is selected from at least one of straight-run light naphtha and hydrocracked light naphtha.

4. The method according to claim 1 or 3, characterized in that: The initial boiling point of the light naphtha is 15–30°C, and the final boiling point is 60–90°C; and / or, the mass content of C5-C6 isoalkanes in the light naphtha is 30%–100%, preferably 50%–90%.

5. The method according to claim 1, characterized in that: The hydroconversion reaction conditions are as follows: reaction pressure 1.0–8.0 MPa, reaction temperature 350–550 °C, hydrogen-to-oil volume ratio 50:1–2000:1, and liquid hourly space velocity 0.2–10.0 h⁻¹. -1 Preferably, the reaction pressure is 2.0–6.0 MPa, the reaction temperature is 400–500 °C, the hydrogen-to-oil volume ratio is 100:1–1000:1, and the liquid hourly space velocity is 0.5–5.0 h⁻¹. -1 .

6. The method according to claim 1, characterized in that: In the hydroconversion catalyst, based on the weight of the catalyst, the content of Group VIII metals as oxides is 1.0% to 6.0%, preferably 2.0% to 6.0%, the content of Group VIB metals as oxides is 2.0% to 24.0%, preferably 6.5% to 22.0%, the content of macroporous alumina is 20.0% to 60.0%, preferably 21.0% to 56.0%, and the content of ZSM-5 & SAPO-34 eutectic molecular sieve is 15.0% to 70.0%.

7. The method according to claim 1, characterized in that: In the hydroconversion catalyst, the Group VIB metal is preferably molybdenum and / or tungsten, and the Group VIII metal is preferably cobalt and / or nickel.

8. The method according to claim 1, characterized in that: The specific surface area of ​​the hydroconversion catalyst is 200–400 m². 2 / g, with a pore volume of 0.20~0.40mL / g.

9. The method according to claim 1, characterized in that: The macroporous alumina in the aforementioned hydroconversion catalyst has the following properties: pore volume of 0.7–1.0 mL / g and specific surface area of ​​200–500 m² / g. 2 / g; and / or, the pore volume of the ZSM-5 & SAPO-34 eutectic molecular sieve is 0.23–0.26 cm³. 3 / g, specific surface area of ​​500-560m² 2 / g, the silicon-aluminum molar ratio SiO2:Al2O3 is 1.5~4.

0.

10. The method according to claim 1 or 6, characterized in that: In the hydrogenation conversion catalyst, M x / M y The value is 1.30 to 2.80, preferably 1.50 to 2.50, wherein M x M represents the molar ratio of Group VIII metal atoms to Group VIB metal atoms in the bulk catalyst phase. y The molar ratio of Group VIII metal atoms to Group VIB metal atoms on the catalyst surface is given.

11. A catalyst for the hydrotreating and upgrading of light naphtha, comprising ZSM-5 & SAPO-34 eutectic molecular sieves supported on Group VIII metals and macroporous alumina supported on Group VIB and Group VIII metals.

12. The catalyst according to claim 11, characterized in that: In the hydrogenation conversion catalyst, M x / M y The value is 1.30 to 2.80, preferably 1.50 to 2.50, wherein M x M represents the molar ratio of Group VIII metal atoms to Group VIB metal atoms in the bulk catalyst phase. y The molar ratio of Group VIII metal atoms to Group VIB metal atoms on the catalyst surface is given.

13. The catalyst according to claim 11 or 12, characterized in that: In the ZSM-5 & SAPO-34 eutectic molecular sieve loaded with Group VIII metals, a solution containing a Group VIII metal amine complex is used as the impregnation solution to load the eutectic molecular sieve.

14. The catalyst according to claim 11, characterized in that: In ZSM-5 & SAPO-34 eutectic molecular sieves, the mass content of ZSM-5 molecular sieve is 20% to 50%, and the mass content of SAPO-34 molecular sieve is 50% to 80%.

15. The catalyst according to claim 11, characterized in that: Group VIB metals are preferably molybdenum and / or tungsten, and Group VIII metals are preferably cobalt and / or nickel.

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