Method for producing low-carbon olefin raw material through hydro-conversion of reformed raffinate oil

Abstract

The invention discloses a method for producing a low-carbon olefin raw material through hydro-conversion of reformed raffinate oil. The method comprises the following steps: mixing reforming raffinate oil with hydrogen, and feeding the mixture into a hydrofining reaction zone for hydrofining reaction; the obtained reaction effluent enters a hydro-conversion reaction zone for a hydro-conversion reaction, the product enters a separation system, and the separated C4 + product is circulated to the hydro-conversion reaction zone for a hydro-conversion reaction to obtain ethane and propane; wherein a hydro-conversion catalyst filled in the hydro-conversion reaction zone comprises beta amp loaded with 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. The reformed raffinate oil processed by the method can be converted into low-carbon alkane such as C2, C3 and the like, so that the yield of low-carbon olefin prepared by steam cracking is improved.

Description

Technical Field

[0001] This invention relates to the field of comprehensive utilization of reforming residue oil, specifically to a method for producing low-carbon olefin feedstock by hydroconversion of reforming residue oil. Background Technology

[0002] Aromatic extraction is a process technology that utilizes the different solubilities of hydrocarbon molecules in solvents to separate aromatic and non-aromatic components. It plays an irreplaceable role in the production of BTX (benzene, toluene, xylene) in the petroleum refining industry. The raffinate obtained after aromatic extraction from catalytic reforming oil contains virtually no aromatic components, resulting in a low octane number and making it unsuitable for use as a blending component in automotive gasoline. Looking at the hydrocarbon composition of reforming raffinate, the main components are alkanes and a small amount of cyclic hydrocarbons, making it a high-quality feedstock for steam cracking to produce low-carbon olefins. Developing this technology is of great significance for the major trend of transformation from petroleum refining to chemical industry; however, current research on raffinate as a steam cracking feedstock is limited.

[0003] CN201710984489.4 proposes a method for producing ethylene using aromatic raffinate as feedstock. The method includes: the aromatic raffinate entering a hydrogenation reactor; the effluent from the hydrogenation reaction being fed into a stabilizer for gas-liquid separation; and the bottom product being fed into an ethylene cracking unit; a crossover line being installed to isolate the hydrogenation reactor from the stabilizer and ethylene cracking unit, allowing the aromatic raffinate to be directly introduced into the stabilizer; and a leak-proof pipeline being installed, with one end connected to the crossover line and the other end connected to the outlet pipeline of the stabilizer bottom circulation pump.

[0004] CN201710986194.0 proposes a method for producing ethylene from aromatic hydrocarbon raffinate as feedstock. The method includes: the aromatic hydrocarbon raffinate enters a hydrogenation reactor; the effluent from the hydrogenation reaction is fed into a stabilizer for gas-liquid separation; and the bottom product from the stabilizer is then fed into an ethylene cracking unit for cracking to produce ethylene. When the hydrogenation reactor is started, the aromatic hydrocarbon raffinate first enters the stabilizer, and then the bottom product from the stabilizer is introduced into the hydrogenation reactor for hydrogenation. The effluent from the hydrogenation reaction is fed into the stabilizer for 5 minutes to 24 hours. Then, the direct feeding of the aromatic hydrocarbon raffinate into the stabilizer and the introduction of the bottom product from the stabilizer into the hydrogenation reactor are stopped. The aromatic hydrocarbon raffinate is then directly introduced into the hydrogenation reactor for normal hydrogenation.

[0005] Although the above methods have solved the problems of substandard product quality and shortened operating cycle in the early stage of hydrotreating unit operation, slowed down the coking rate of cracking furnace tubes and extended the coking cycle, the efficiency of cracking to produce low-carbon olefins is low due to the high proportion of isomeric and cyclic hydrocarbons in the raffinate oil. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method for producing low-carbon olefin feedstock by hydroconversion of reforming raffinate. This method can process reforming raffinate into low-carbon alkanes such as C2 and C3, thereby improving the yield of low-carbon olefins from steam cracking.

[0007] The first aspect of this invention provides a method for producing low-carbon olefin feedstock by hydroconversion of reforming residue oil, the method comprising:

[0008] (1) The reforming residue oil is mixed with hydrogen and then enters the hydrorefining reaction zone for hydrorefining reaction;

[0009] (2) The reaction effluent obtained in step (1) enters the hydroconversion reaction zone for hydroconversion reaction, and the product enters the separation system to separate the C4. + The product is recycled to the hydroconversion reaction zone to continue the hydroconversion reaction, yielding ethane and propane;

[0010] The hydroconversion reaction zone is filled with a hydroconversion catalyst, which includes a β&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.

[0011] In the method of the present invention, in the β&SAPO-34 eutectic molecular sieve loaded with Group VIII metals, a solution containing a Group VIII metal amine complex is used as an impregnation solution loaded onto the eutectic molecular sieve.

[0012] In the method of this invention, the hydrorefining reaction conditions are as follows: reaction pressure 1.0–6.0 MPa, reaction temperature 100–250 °C, hydrogen-to-oil volume ratio 200:1–800:1, and liquid hourly space velocity 0.5–4.0 h⁻¹. -1 .

[0013] In the method of this invention, the hydroconversion reaction conditions are as follows: reaction pressure is 1.0–6.0 MPa, reaction temperature is 380–500 °C, hydrogen-to-oil volume ratio is 200:1–800:1, and liquid hourly space velocity is 0.5–4.0 h⁻¹. -1 .

[0014] In the method of the present invention, the initial boiling point of the reformate raffinate is 40-70°C and the final boiling point is 110-160°C; the mass content of C5-C8 isoalkanes in the reformate raffinate is 50%-80%, and the mass content of olefins is 1%-8%.

[0015] In this invention, the hydrorefining reaction zone is filled with a hydrorefining catalyst, which generally comprises a hydrorefining active metal component and a support. The hydrorefining active metal is molybdenum and nickel, and the support is alumina. Generally, based on the weight of the catalyst, the metal content (calculated as oxide) is 18.0%–22.0%. The hydrorefining catalyst can be the FH-40A catalyst developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. Furthermore, after the hydrorefining reaction, the olefin content in the light naphtha feedstock is reduced to below 0.5%.

[0016] In the method of this invention, the specific surface area of ​​the hydroconversion catalyst is 300–450 m². 2 / g, with a pore volume of 0.30~0.45mL / g.

[0017] In the method of this invention, the hydroconversion catalyst, based on the weight of the catalyst, contains 1.0%–6.0% of Group VIII metals (calculated as oxides), 5.0%–25.0% of Group VIB metals (calculated as oxides), 20.0%–65.0% of macroporous alumina, and 15.0%–70.0% of β&SAPO-34 eutectic molecular sieve. Further, the macroporous alumina has the following properties: pore volume of 0.7–1.0 mL / g, and specific surface area of ​​200–500 m². 2 / g. Among them, Group VIB metals are preferably molybdenum and / or tungsten, and Group VIII metals are preferably cobalt and / or nickel.

[0018] In the method of the present invention, the molar ratio X of the bulk group VIII metal atoms to the surface group VIII metal atoms of the hydroconversion catalyst is 1.5 to 4.0, preferably 2.0 to 3.0.

[0019] Furthermore, the mass of the bulk group VIII metal oxides in the catalyst was determined by X-ray fluorescence spectroscopy, and the mass of the group VIII metal oxides on the catalyst surface was determined by X-ray photoelectron spectroscopy.

[0020] The method of the present invention includes the following steps for preparing the hydroconversion catalyst:

[0021] (1) Mix the metal amine complex solution containing group VIII metal salt with β&SAPO-34 eutectic molecular sieve, perform sealed impregnation treatment, dry and calcinate to obtain β&SAPO-34 eutectic molecular sieve loaded with group VIII metal.

[0022] (2) Macroporous alumina was impregnated with an aqueous solution containing Group VIB metal salt and Group VIII metal salt, dried and calcined to obtain macroporous alumina loaded with Group VIB metal and Group VIII metal.

[0023] (3) Mix β&SAPO-34 eutectic molecular sieve loaded with Group VIII metals and macroporous alumina loaded with Group VIB metals and Group VIII metals, shape, dry and calcine to obtain a hydroconversion catalyst.

[0024] Further, the preparation process of the solution containing the Group VIII metal amine complex in step (1) is as follows: dissolve the Group VIII metal salt in deionized water, stir evenly, and then add 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.

[0025] Furthermore, in the β&SAPO-34 eutectic molecular sieve described in step (1), the mass content of β molecular sieve is 20% to 60%, and the mass content of SAPO-34 molecular sieve is 40% to 80%.

[0026] Furthermore, the β&SAPO-34 eutectic molecular sieve described in step (1) can be prepared using the following steps:

[0027] (a) Mix silicon source, aluminum source, phosphorus source, template agent and water to obtain a mixed slurry;

[0028] (b) The hydrogen-type β molecular sieve is mixed with the mixed slurry obtained in step (a), crystallized, and calcined to obtain the hydrogen-type β&SAPO-34 eutectic molecular sieve.

[0029] Further, the molar ratio of silicon source, aluminum source, phosphorus source, template agent and water in step (a) is (0.2~1.0)SiO2:1.0Al2O3:(0.9~1.2)P2O5:(0.5~8)R (template agent):(10~200)H2O.

[0030] Further, in step (b), the amount of hydrogen-type β molecular sieve added is 40% to 200% of the mass of silicon source (in SiO2) in the mixed slurry of step (a).

[0031] Further, in step (b), the crystallization conditions include: crystallization at 180–200°C for 2–4 days.

[0032] Further, in step (b), after crystallization, the product is washed with deionized water until the pH value is 7-8, then filtered, dried at 100-120℃ for 3-6 hours, and calcined at 500-600℃ for 4-8 hours to obtain hydrogen-form β&SAPO-34 eutectic molecular sieve.

[0033] Furthermore, the pore volume of the β&SAPO-34 eutectic molecular sieve is 0.31–0.36 cm³. 3 / g, with a specific surface area of ​​590–640m² 2 / g, the silicon-aluminum molar ratio SiO2:Al2O3 is 2.5~7.0.

[0034] Furthermore, in the preparation process of the β&SAPO-34 eutectic molecular sieve, the silicon source is selected from one or more of silica sol, silica, and tetraethyl orthosilicate; the aluminum source is selected from one or more of aluminum sulfate octadecylhydrate, aluminum isopropoxide, and boehmite; the phosphorus source is phosphoric acid; the template agent is selected from one or more of isopropylamine, triethylamine, tetraethylammonium hydroxide, and morpholine; and the water is deionized water. The hydrogen-form β-molecular sieve can be a commercially available molecular sieve with a pore volume of 0.30–0.45 cm³. 3 / g, specific surface area of ​​500-700m² 2 / g, the silicon-aluminum molar ratio SiO2:Al2O3 is 40~120.

[0035] Further, the closed impregnation process in step (1) is as follows: β&SAPO-34 eutectic molecular sieve is placed in a metal amine complex solution in a closed reaction vessel, and then heated to 100-120℃ 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 β&SAPO-34 eutectic molecular sieve to the metal amine complex solution is 1:2 to 1:5.

[0036] Further, after impregnation in step (1), β&SAPO-34 eutectic molecular sieve loaded with Group VIII metal is obtained by conventional filtration, drying and calcination. 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.

[0037] Further, in the aqueous solution containing Group VIB and Group VIII metal salts described in step (2), the Group VIB metal salt is one or more of tungsten salts (such as ammonium metatungstate) or molybdenum salts (such as ammonium molybdate), and the Group VIII metal salt 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.

[0038] Furthermore, the impregnation in step (2) is supersaturated impregnation, and the solid-liquid volume ratio of macroporous alumina to the aqueous solution containing Group VIB metals and Group VIII metals is 1:2 to 1:5.

[0039] Further, after impregnation in step (2), macroporous alumina loaded with Group VIB and Group VIII metals is obtained by conventional filtration, drying and calcination. 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.

[0040] 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 β&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 β&SAPO-34 eutectic molecular sieve loaded with Group VIII metals and the macroporous alumina loaded with Group VIB and Group VIII metals.

[0041] Further, in step (3), after molding, the catalyst is dried and 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.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] This invention utilizes a hydrorefining zone to hydrogenate and saturate the unsaturated hydrocarbon components in reformate raffinate, which then enters a hydroconversion zone to convert them into C2 and C3 low-carbon alkanes. The β&SAPO-34 eutectic molecular sieve catalyst packed in the hydroconversion zone combines the high acid strength cracking of the macroporous twelve-membered ring β-molecular sieve with the pore-confined synergistic catalytic function of the small-pore eight-membered ring SAPO-34 molecular sieve, effectively improving the selectivity for producing C2 and C3 low-carbon alkanes from the reformate raffinate cracking. The low-carbon alkanes generated from the reformate raffinate conversion can be separated by a separation system, while the remaining C4... + The product is recycled back to the hydrogenation conversion zone for further cracking, which further increases the yield of C2 and C3 low-carbon alkanes and reduces the yield of methane by-product, thereby significantly improving the quality of the feedstock for steam cracking to produce low-carbon olefins.

[0044] The reformate raffinate contains a high content of C5-C8 alkanes. Since alkanes have weak adsorption capacity during hydroconversion, improving the distance between the acidic centers and metal active sites of the catalyst is beneficial to enhancing the catalyst's activity and selectivity, thereby achieving deep conversion of the raffinate into C2 and C3 low-carbon alkanes. The inventors discovered that during the preparation of the hydroconversion catalyst, by impregnating the β&SAPO-34 eutectic molecular sieve under self-generated pressure using a Group VIII metal amine complex solution, the basic groups of the metal amine complex selectively adsorb and bind with the acidic centers within the molecular sieve pores, effectively shortening the distance between the metal active centers and the acidic sites of the molecular sieve. This accelerates the rate of the cracking reaction after dehydrogenation of the raffinate molecules and increases the conversion depth of the cracking reaction. Furthermore, the eutectic molecular sieve exhibits a more uniform distribution of acidic centers, which, compared to a simple mechanical mixing of the two molecular sieves, better integrates the high-acid-strength cracking of the macroporous twelve-membered ring molecular sieve with the pore-confined synergistic catalytic function of the small-pore eight-membered ring molecular sieve. Then, the macroporous alumina is impregnated with a mixed aqueous solution containing Group VIB metals and Group VIII metal salts. This allows the bimetallic active centers with stronger hydrogenation activity to be selectively adsorbed in the macroporous alumina. This enables the small molecule olefins generated from the cracking of raffinate oil to diffuse out of the molecular sieve channels and quickly become saturated, effectively improving the catalytic activity.

[0045] In the method of this invention, a full-cycle process is adopted. The C2-C3 low-carbon alkane products generated by the reforming raffinate can be separated by a separation system, while the remaining C4... + The hydrocarbon products are recycled to the hydroconversion reaction zone for further cracking. The proportion of ethane and propane in the products reaches more than 92%, and the proportion of methane by-product can be reduced to below 8.0%, achieving maximum production of C2-C3 low-carbon alkane products. Attached Figure Description

[0046] Figure 1The XRD patterns of the β&SAPO-34 eutectic molecular sieve obtained in Example 1, the commercially available β molecular sieve, and the SAPO-34 molecular sieve obtained in Comparative Example 4 are shown.

[0047] Figure 2 This is a schematic diagram of the process flow of the embodiments and comparative examples of the present invention;

[0048] Explanation of key figure labels:

[0049] 1-Reform raffinate, 2-Hydrogen, 3-Hydrorefining reaction zone, 4-Hydrorefining catalyst, 5-Hydrorefining product, 6-Hydroconversion reaction zone, 7-Hydroconversion catalyst, 8-Hydroconversion product, 9-Separator, 10-Hydrogen-rich gas stream, 11-Liquid stream, 12-Fracturing column, 13-Gaseous product, 14-C4 + product.

[0050] In this invention, the olefin content of the reformate after hydrorefining is 0.35%. Detailed Implementation

[0051] 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.

[0052] In this invention, the mass of the bulk group VIII metal oxide catalyst was obtained by X-ray fluorescence spectroscopy (XRF) analysis using a ZSX100e X-ray fluorescence spectrometer with Kα spectral line, LiF1 crystal, Rh target material, SC scintillation detector, timing of 20 s, and vacuum atmosphere.

[0053] In this invention, the mass of the Group VIII metal oxide on the catalyst surface was determined by X-ray photoelectron spectroscopy (XPS). The elemental composition and state of the catalyst surface (3 nm–10 nm) were measured 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).

[0054] In this invention, unless otherwise specified, all percentages (%) in the embodiments and comparative examples refer to mass fractions.

[0055] The hydrogen-form β-zeolite involved in the embodiments and comparative examples of this invention is a commercially available product with a pore volume of 0.39 cm³. 3 / g, specific surface area is 641m² 2 The silicon-aluminum molar ratio (SiO2:Al2O3) was 72 / g. The properties of the prepared β&SAPO-34 eutectic molecular sieve are shown in Table 2. The pore volume of the prepared SAPO-34 molecular sieve was 0.29 cm³.3 / g, specific surface area is 572cm³ 2 / g, the silicon-to-aluminum molar ratio of SiO2:Al2O3 is 0.5. 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.

[0056] In this invention, the formulas for calculating the conversion rate and product yield of reformate raffinate are as follows:

[0057] Single-pass conversion rate = [1 - (loop C4)] + Hydrocarbon mass / (Cyclic C4) + [Hydrocarbon mass + Fresh raw material mass] × 100%,

[0058] C2+C3 yield = (sum of the masses of C2 and C3 in the product) / (sum of the masses of C1, C2, and C3 in the product) × 100%

[0059] C1, C2, and C3 respectively name methane, ethane, and propane.

[0060] Example 1

[0061] 461.2 g of phosphoric acid (H3PO4 mass fraction 85%) was dissolved in 1548.0 g of deionized water. During stirring, 279.4 g of boehmite (Al2O3 mass fraction 73%), 606.0 g of triethylamine (TEA), and 180.0 g of silica sol (SiO2 mass fraction 40%) were added sequentially to form a mixed gel of 0.6 SiO2:Al2O3:P2O5:3 TEA:50 H2O. 72 g of hydrogen-form β molecular sieve was added to the mixed gel and stirred evenly. The mixture 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, dried at 120℃ for 4 h, and calcined at 550℃ for 6 h to obtain hydrogen-form β&SAPO-34 eutectic molecular sieve, denoted as β&S-1. In β&S-1, the mass content of β molecular sieve is 41.8%, and the mass content of SAPO-34 molecular sieve is 58.2%.

[0062] 40g 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 3.0g / 100mL. 100g of β&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 temperature was raised to 100℃ 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 denoted as N-1.

[0063] Take 200g of macroporous alumina and immerse it in 400mL of an aqueous solution with a nickel content (calculated as oxide) of 2.0g / 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, the resulting material is denoted as NW-1.

[0064] Take 100g of N-1 and 200g of NW-1, 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 catalyst CAT-1, the properties of which are shown in Table 1.

[0065] Example 2

[0066] The preparation process of the eutectic molecular sieve β&S in this embodiment is the same as in Example 1.

[0067] 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 β&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 as N-2.

[0068] Take 200g of macroporous alumina and immerse it 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 50.0g / 100mL for 2h. After filtration, drying at 120℃ for 6h and calcining at 550℃ for 4h, the resulting material is denoted as NW-2.

[0069] Take 100g of N-2 and 50g of NW-2, mix them, and put them into a rolling mill for grinding. Add 60g 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.

[0070] Comparative Example 1

[0071] The preparation process of the eutectic molecular sieve β&S in this embodiment is the same as in Example 1.

[0072] 100g of β&S-1 molecular sieve and 200g of macroporous alumina were impregnated in 600mL of an aqueous solution containing 5.0g / 100mL of nickel (calculated as oxide) and 20.0g / 100mL of tungsten (calculated as oxide) for 2 hours. After filtration, drying at 120℃, and calcination at 550℃ for 4 hours, the resulting material was denoted as DNW-1. DNW-1 was then mixed and milled in a mill, and 120g 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 6 hours, and then calcined at 550℃ for 4 hours to obtain the comparative catalyst DCAT-1, the properties of which are shown in Table 1.

[0073] Comparative Example 2

[0074] The preparation process of the eutectic molecular sieve β&S in this embodiment is the same as in Example 1.

[0075] 600g 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 15g / 100mL. 100g of β&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.

[0076] Take 200g of macroporous alumina, soak it in 400mL of an aqueous solution with a tungsten content (calculated as oxide) of 50.0g / 100mL for 2h, filter it, dry it at 120℃ for 6h, and calcine it at 550℃ for 4h. The resulting material is denoted as DW-2.

[0077] Take 100g of DN-2 and 50g of DW-2, mix them, and put them into a rolling mill for grinding. Add 60g 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.

[0078] Comparative Example 3

[0079] The preparation process of the eutectic molecular sieve β&S in this embodiment is the same as in Example 1.

[0080] 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 3.0g / 100mL. 100g of β&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, the resulting material was designated DN-3.

[0081] Take 200g of macroporous alumina and immerse it in 400mL of an aqueous solution with a nickel content (calculated as oxide) of 2.0g / 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, the resulting material is denoted as DNW-3.

[0082] Take 100g of DN-3 and 200g of DNW-3, 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 catalyst DCAT-3, the properties of which are shown in Table 1.

[0083] Comparative Example 4

[0084] Preparation of SAPO-34 molecular sieve:

[0085] 461.2 g of phosphoric acid (85% H3PO4 by mass) was dissolved in 1548.0 g of deionized water. During stirring, 279.4 g of boehmite (73% Al2O3 by mass), 606.0 g of triethylamine (TEA), and 180.0 g of silica sol (40% SiO2 by mass) 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.

[0086] 40g 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 3.0g / 100mL. 20g of hydrogen-type β-molecular sieve and 80g of the above-mentioned SAPO-34 molecular sieve were mixed with 200mL of the above-mentioned nickel-amine complex solution and placed in a reaction vessel. After sealing, the mixture was stirred at 150rpm, 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, the resulting material was designated DN-4.

[0087] Take 200g of macroporous alumina and immerse it in 400mL of an aqueous solution with a nickel content (calculated as oxide) of 2.0g / 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, the resulting material is denoted as DNW-4.

[0088] Take 100g of DN-4 and 200g of DNW-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 catalyst DCAT-4, the properties of which are shown in Table 1.

[0089] Example 3

[0090] The preparation process of the eutectic molecular sieve β&S in this embodiment is the same as in Example 1.

[0091] 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 β&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. The resulting material was designated C-3.

[0092] Take 200g of macroporous alumina, soak it in 400mL 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, filter it, dry it at 120℃ for 6h, and calcine it at 550℃ for 4h. The resulting material is denoted as CM-3.

[0093] 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.

[0094] Example 4

[0095] The preparation process of the eutectic molecular sieve β&S in this embodiment is the same as in Example 1.

[0096] 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 12g / 100mL. 100g of β&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 heated to 110℃ with stirring at 300rpm for 4 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 N-4.

[0097] Take 200g of macroporous alumina, soak it in 400mL of an aqueous solution with a nickel content (calculated as oxide) of 6g / 100mL and a molybdenum content (calculated as oxide) of 60g / 100mL for 2h, filter it, dry it at 120℃ for 6h, and calcine it at 550℃ for 4h. The resulting material is denoted as NM-4.

[0098] Take 100g of N-4 and 125g of NM-4, mix them, and put them into a rolling mill for grinding. Add 90g 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.

[0099] Example 5

[0100] The preparation process of the eutectic molecular sieve β&S in this embodiment is the same as in Example 1.

[0101] 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 8g / 100mL. 100g of β&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 heated to 120℃ with stirring at 350rpm for 4 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 C-5.

[0102] Take 200g of macroporous alumina, soak it in 200mL of an aqueous solution with a cobalt content (calculated as oxide) of 4g / 100mL and a tungsten content (calculated as oxide) of 40.0g / 100mL for 2h, filter it, dry it at 120℃ for 6h, and calcine it at 550℃ for 4h. The resulting material is denoted as CW-5.

[0103] Take 100g of C-5 and 100g of CW-5, 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-5, the properties of which are shown in Table 1.

[0104] Example 6

[0105] The preparation process of the eutectic molecular sieve β&S in this embodiment is the same as in Example 1.

[0106] 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 6.0g / 100mL. 100g of β&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, a macroporous twelve-membered ring & microporous eight-membered ring eutectic molecular sieve loaded with Group VIII metals was obtained, denoted as N-6.

[0107] Take 200g of macroporous alumina and immerse it in 400ml of an aqueous solution with a nickel content (calculated as oxide) of 3.0g / 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, macroporous alumina loaded with Group VIB and Group VIII metals is obtained, denoted as NW-6.

[0108] Take 100g of N-6 and 75g of NW-6, mix them, and put them into a rolling mill for grinding. Add 70g 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.

[0109] Example 7

[0110] The preparation process of the eutectic molecular sieve β&S-2 in this embodiment is as follows:

[0111] 461.2 g of phosphoric acid (H3PO4 mass fraction 85%) was weighed and dissolved in 1548.0 g of deionized water. During stirring, 279.4 g of boehmite (Al2O3 mass fraction 73%), 606.0 g of triethylamine (TEA), and 180.0 g of silica sol (SiO2 mass fraction 40%) were added sequentially to form a mixed gel of 0.6 SiO2:Al2O3:P2O5:3 TEA:50 H2O. 28.8 g of hydrogen-form β molecular sieve was added to the mixed gel and stirred evenly. The mixture 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, dried at 120℃ for 4 h, and calcined at 550℃ for 6 h to obtain hydrogen-form β&SAPO-34 eutectic molecular sieve, denoted as β&S-2. In β&S-2, the mass content of β molecular sieve is 21.4%, and the mass content of SAPO-34 molecular sieve is 78.6%.

[0112] The catalyst preparation method in this embodiment is the same as in Example 3, except that 100g of β&S-1 molecular sieve is replaced with an equal amount of β&S-2 molecular sieve to obtain catalyst CAT-7, the properties of which are shown in Table 1.

[0113] Example 8

[0114] The preparation process of the eutectic molecular sieve β&S-3 in this embodiment is as follows:

[0115] 461.2 g of phosphoric acid (H3PO4 mass fraction 85%) was weighed and dissolved in 1548.0 g of deionized water. During stirring, 279.4 g of boehmite (Al2O3 mass fraction 73%), 606.0 g of triethylamine (TEA), and 180.0 g of silica sol (SiO2 mass fraction 40%) were added sequentially to form a mixed gel of 0.6SiO2:Al2O3:P2O5:3TEA:50H2O. 144 g of hydrogen-form β-molecular sieve was added to the mixed gel and stirred evenly. The mixture 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, dried at 120℃ for 4 h, and calcined at 550℃ for 6 h to obtain hydrogen-form β&SAPO-34 eutectic molecular sieve, denoted as β&S-3. In β&S-3, the mass content of β molecular sieve is 59.1%, and the mass content of SAPO-34 molecular sieve is 40.9%.

[0116] The catalyst preparation method in this embodiment is the same as in Example 3, except that 100g of β&S-1 molecular sieve is replaced with an equal amount of β&S-3 molecular sieve to obtain catalyst CAT-8, the properties of which are shown in Table 1.

[0117] Table 1. Properties of the catalysts obtained in each example.

[0118]

[0119] Table 2. Properties of the eutectic molecular sieves obtained in each example.

[0120]

[0121] Example 9

[0122] This embodiment describes the evaluation method and results of the method of the present invention. Catalysts CAT-1 to CAT-8 and comparative catalysts DCAT-1 to DCAT-4 were evaluated in a fixed-bed hydrogenation test apparatus under the same process conditions: reaction pressure 3.0 MPa, hydrogen-to-oil volume ratio 400:1, and purification reaction volume hourly space velocity 2.0 h⁻¹. 1 The purification reaction temperature was 180℃, and the volume hourly space velocity (VHSV) of the hydrogenation reaction was 1.5 h⁻¹. 1 The conversion reaction temperature was 440℃, and a single-stage series full-cycle process was used for the conversion reaction of the reformate. The refining catalyst was the commercially available catalyst FH-40A. The feedstock used for evaluation was reformate, and its properties are shown in Table 3. The evaluation results are shown in Tables 4 and 5.

[0123] The evaluation results show that the method of the present invention has a higher single-pass conversion rate of reforming raffinate, and the yields of C2 and C3 in the obtained hydroconversion products are higher, while the methane yield is lower. This significantly improves the quality of steam cracking feedstock and is beneficial to increasing the yield of low-carbon olefins.

[0124] Table 3 Properties of Reforming Residue Oil Feedstock

[0125] Carbon number composition <![CDATA[C5-C8]]> <![CDATA[Density, g / cm 3 > 0.62 Distillation range, °C 45～130 Sulfur content, ppm 6.3 <![CDATA[Bromine number, gBr2 / 100g]]> 23.0 Composition, wt% n-Alkanes 24.6 Isoalkanes 64.5 Cycloalkanes 4.3 n-olefins 1.5 Isoolefins 4.6 Cycloolefins 0.4 Aromatics 0.1

[0126] Table 4 Evaluation results of the catalysts in the examples

[0127] Catalyst number CAT-1 CAT-2 CAT-3 CAT-4 CAT-5 CAT-6 CAT-7 CAT-8 One-way conversion rate, % 64.2 69.0 72.4 75.8 77.0 73.5 72.1 75.3 Product distribution, % <![CDATA[C1]]> 7.5 6.2 5.8 4.4 4.7 5.3 5.5 6.3 <![CDATA[C2]]> 28.8 31.6 33.5 36.2 35.4 34.2 34.6 32.6 <![CDATA[C3]]> 63.7 62.2 60.7 59.4 59.9 60.5 59.9 61.1 <![CDATA[Yield of C2 + C3, %]]> 92.5 93.8 94.2 95.6 95.3 94.7 94.5 93.7

[0128] Table 5 Evaluation results of the comparative example catalysts

[0129] Catalyst number DCAT-1 DCAT-2 DCAT-3 DCAT-4 One-way conversion rate, % 42.3 34.7 54.5 61.4 Product distribution, % <![CDATA[C1]]> 12.8 16.4 14.3 11.2 <![CDATA[C2]]> 26.2 20.8 24.1 28.1 <![CDATA[C3]]> 61.0 62.8 61.6 61.7 <![CDATA[Yield of C2 + C3, %]]> 87.2 83.6 85.7 88.8

[0130] 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 producing low-carbon olefin feedstock by hydroconversion of reforming residue oil, the method comprising: (1) The reforming residue oil is mixed with hydrogen and then enters the hydrorefining reaction zone for hydrorefining reaction; (2) The reaction effluent obtained in step (1) enters the hydroconversion reaction zone for hydroconversion reaction, and the product enters the separation system to separate the C4. + The product is recycled to the hydrogenation conversion reaction zone to continue the hydrogenation conversion reaction, yielding ethane and propane; The hydroconversion reaction zone is filled with a hydroconversion catalyst, which includes a β&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.

2. The method according to claim 1, characterized in that: The hydrorefining reaction conditions are as follows: reaction pressure 1.0–6.0 MPa, reaction temperature 100–250 °C, hydrogen-to-oil volume ratio 200:1–800:1, and liquid hourly space velocity 0.5–4.0 h⁻¹. -1 .

3. The method according to claim 1, characterized in that: The hydroconversion reaction conditions are as follows: reaction pressure 1.0–6.0 MPa, reaction temperature 380–500 °C, hydrogen-to-oil volume ratio 200:1–800:1, and liquid hourly space velocity 0.5–4.0 h⁻¹. -1 .

4. The method according to claim 1, characterized in that: The initial boiling point of the reformate raffinate is 40–70°C, and the final boiling point is 110–160°C; preferably, the mass content of C5-C8 isoalkanes in the reformate raffinate is 50%–80%, and the mass content of olefins is 1%–8%.

5. The method according to claim 1, characterized in that: The hydroconversion catalyst, based on the weight of the catalyst, contains 1.0% to 6.0% of Group VIII metals as oxides, 5.0% to 25.0% of Group VIB metals as oxides, 20.0% to 65.0% of macroporous alumina, and 15.0% to 70.0% of β&SAPO-34 eutectic molecular sieve.

6. The method according to claim 1 or 5, characterized in that: Group VIB metals are preferably molybdenum and / or tungsten, and Group VIII metals are preferably cobalt and / or nickel.

7. The method according to claim 1, characterized in that: The specific surface area of ​​the hydroconversion catalyst is 300–450 m². 2 / g, with a pore volume of 0.30~0.45mL / g.

8. The method according to claim 1, characterized in that: The macroporous alumina 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 β&SAPO-34 eutectic molecular sieve is 0.31–0.36 cm³. 3 / g, with a specific surface area of ​​590–640m² 2 / g, the silicon-aluminum molar ratio SiO2:Al2O3 is 2.5~7.

0.

9. The method according to claim 1, characterized in that: In the β&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.

10. The method according to claim 1, characterized in that: The molar ratio X of the bulk group VIII metal atoms to the surface group VIII metal atoms of the hydrogenation conversion catalyst is 1.5 to 4.0, preferably 2.0 to 3.

0.

11. A reforming raffinate hydroconversion catalyst, comprising a β&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.

12. The catalyst according to claim 11, characterized in that: The molar ratio X of the bulk group VIII metal atoms to the surface group VIII metal atoms of the hydrogenation conversion catalyst is 1.5 to 4.0, preferably 2.0 to 3.

0.

13. The catalyst according to claim 11 or 12, characterized in that: In the β&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 the β&SAPO-34 eutectic molecular sieve, the mass content of β molecular sieve is 20% to 60%, and the mass content of SAPO-34 molecular sieve is 40% 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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