A lipid hydrodeoxygenation catalyst, a preparation method and application thereof

Abstract

The application discloses an oil hydrogenation deoxidization catalyst and a preparation method and application thereof. The oil hydrogenation deoxidization catalyst comprises the following components by weight of the final catalyst: a) HZSM-23 molecular sieve, 3-15 wt%; b) beta molecular sieve, 5-20 wt%; c) macroporous alumina, 65-85 wt%; and d) noble metal active component, 0.05-5.0 wt% in terms of element. The bulk SiO2 / Al2O3 molar ratio of the HZSM-23 molecular sieve is 40-400 higher than the external surface SiO2 / Al2O3 molar ratio. The catalyst provided by the application can effectively remove carboxyl groups and avoid excessive breaking of long-chain alkanes to generate small-molecule alkanes, thereby ensuring the yield of alkanes and effectively improving the low-temperature fluidity of the alkanes.

Description

Technical Field

[0001] This invention relates to a hydrodeoxygenation catalyst, its preparation method, and its application; more specifically, it relates to a hydrodeoxygenation catalyst suitable for oils and fats, its preparation method, and its application. Background Technology

[0002] Biomass energy, with its carbon derived from nature and carbon-neutral throughout its life cycle, has become one of the most promising development areas in the process of greening and decarbonizing energy. Biodiesel, in particular, can effectively mitigate the carbon emissions associated with traditional petrochemical diesel. It can not only completely replace petrochemical diesel but also alleviate the supply-demand imbalance between dwindling oil resources and rising demand, adjust the refined oil supply structure, and reduce greenhouse gas emissions. Biodiesel production can form a closed loop through the recycling of waste cooking oil without occupying land or competing with humans for food, exhibiting outstanding environmental attributes. First-generation biodiesel faced limitations in its adoption due to poor low-temperature performance and restricted dosage. The second-generation biodiesel production technology utilizes hydrodeoxygenation technology to deoxygenate and modify oils, preparing aliphatic hydrocarbons with a molecular structure closer to petrochemical diesel. However, the production of second-generation biodiesel still faces challenges such as high catalyst prices and poor stability leading to deactivation.

[0003] CN113786857A discloses a biodiesel hydrodeoxygenation-isomerization catalyst, its preparation method, and its application. The method involves dispersing an aluminum source, a phosphorus source, and a silicon source in deionized water to form a gel mixture. A nickel source is then added and dispersed in the gel mixture. The mixture is placed in a reactor, and a template agent, a pore-expanding agent, and deionized water are added. After stirring and mixing, the mixture is dried, crystallized, and then calcined at 610–650℃ for 5–7 hours to obtain a nickel-doped SAPO-11 support. The SAPO-11 support, boehmite, guar gum powder, and acetic acid solution are mixed, ground, stirred, extruded, and dried to prepare a catalyst precursor. Finally, the catalyst precursor is subjected to a reduction reaction in a reducing gas atmosphere, followed by phosphating to obtain the catalyst. This method incorporates active nickel during the molecular sieve process. However, during the high-temperature calcination at 610–650℃, nickel species may agglomerate, which is detrimental to the full utilization of the metal's properties. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a catalyst for the hydrodeoxygenation of oils and fats, its preparation method, and its application. The catalyst provided by this invention, when used in the hydrodeoxygenation reaction of oils and fats, can effectively remove carboxyl groups and avoid excessive breakage of long-chain alkanes to generate small-molecule alkanes, ensuring the yield of alkanes and effectively improving their low-temperature fluidity.

[0005] The first aspect of this invention provides a catalyst for the hydrodeoxygenation of oils and fats, comprising the following components based on the final weight of the catalyst:

[0006] a) HZSM-23 molecular sieve, with a content of 3-15 wt%, preferably 5-12 wt%;

[0007] b) β molecular sieve, with a content of 5-20 wt%, preferably 8-15 wt%;

[0008] c) Macroporous alumina, with a content of 65-85 wt%, preferably 70-82 wt%;

[0009] d) The content of the noble metal active component, calculated as an element, is 0.05 to 5.0 wt%, preferably 0.1 to 3.5 wt%;

[0010] The bulk SiO2 / Al2O3 molar ratio of the HZSM-23 molecular sieve is 40 to 400 higher than that of the outer surface SiO2 / Al2O3 molar ratio.

[0011] Furthermore, the noble metal active component is at least one of Re, Pt, Pd, Ru, and Rh, preferably Pd and / or Pt.

[0012] Further, the bulk SiO2 / Al2O3 molar ratio of the HZSM-23 molecular sieve is 70-500, and the outer surface SiO2 / Al2O3 molar ratio is 40-120; preferably, the bulk SiO2 / Al2O3 molar ratio of the HZSM-23 molecular sieve is 80-400, and the outer surface SiO2 / Al2O3 molar ratio is 45-90.

[0013] Furthermore, the ratio of the total Brønsted acid content of 2,6-dimethylpyridine infrared radiation to the total Brønsted acid content of pyridine infrared radiation in the HZSM-23 molecular sieve is 65-96:100, preferably 69-93:100; simultaneously, the ratio of the Brønsted acid content of 2,6-dimethylpyridine infrared radiation to the total Brønsted acid content of 2,6-dimethylpyridine infrared radiation at a desorption temperature <250℃ is 67-95:100, preferably 70-92:100.

[0014] Further, the total Brønsted acid content of pyridine in the HZSM-23 molecular sieve is 0.12–0.40 mmol / g, preferably 0.14–0.38 mmol / g; the total Brønsted acid content of 2,6-dimethylpyridine in the HZSM-23 molecular sieve is 0.09–0.40 mmol / g, preferably 0.11–0.33 mmol / g, and the Brønsted acid content of 2,6-dimethylpyridine in the HZSM-23 molecular sieve with a desorption temperature <250℃ is 0.07–0.29 mmol / g, preferably 0.08–0.20 mmol / g.

[0015] Furthermore, the properties of the β-zeolite are as follows: SiO2 / Al2O3 molar ratio is 40–60, and specific surface area is 500–700 m². 2 / g, pore volume 0.35~0.50cm³ 3 / g.

[0016] Furthermore, the macroporous alumina has the following properties: specific surface area of ​​375–450 m² / g. 2 / g, pore volume 0.74~1.15cm 3 / g; preferably, specific surface area is 390-430m² 2 / g, pore volume 0.78~1.10cm 3 / g.

[0017] The second aspect of the present invention provides a method for preparing the above-mentioned oil hydrodeoxygenation catalyst, including the preparation of a catalyst support and loading of an active metal; wherein HZSM-23 molecular sieve, β molecular sieve, macroporous alumina and forming aid are mixed, shaped, dried and calcined to obtain the catalyst support.

[0018] Furthermore, the preparation method of the HZSM-23 molecular sieve includes:

[0019] (1) A mixture of silicon source, template agent a and water is subjected to a crystallization reaction, and a solid material is separated from the reacted material; the solid material, aliphatic amine and inorganic base are mixed and reacted once, and then ZSM-23 seed crystals are added and reacted twice to obtain the reacted material;

[0020] (2) Mix the aluminum source, template agent b and the material obtained in step (1), and then crystallize, filter, wash, dry and calcine in sequence to obtain ZSM-23 molecular sieve;

[0021] (3) The ZSM-23 molecular sieve obtained in step (2) is subjected to ammonium exchange treatment to obtain HZSM-23 molecular sieve.

[0022] Preferably, in step (1), the molar ratio of water, template agent a and silicon source (calculated as SiO2) is (20-80):(0.1-1):1, and more preferably (30-70):(0.15-0.8):1.

[0023] Preferably, in step (1), the silicon source is one or any combination of at least two of the following: silica, silica sol, water glass, fumed silica, and tetraethyl orthosilicate.

[0024] Preferably, in step (1), the template agent a is one or any combination of at least two of hexamethylenediamine, n-hexamethyleneamine, ethanol, tetrapropylammonium hydroxide, tetrapropylammonium bromide and triethylamine.

[0025] Preferably, in step (1), the conditions for the crystallization reaction include: a temperature of 120 to 220°C and a time of 8 to 48 hours.

[0026] Preferably, in step (1), the liquid-to-solid ratio of the fatty amine to the solid material is 0.3 to 3 mL / g, more preferably 0.5 to 2 mL / g.

[0027] Preferably, in step (1), the fatty amine is a C12-C18 fatty amine, more preferably at least one of oleylamine, octadecylamine and dodecylamine.

[0028] Preferably, in step (1), the inorganic base is used in the form of an alkaline solution, and the concentration of the alkaline solution is 0.003 to 0.015 mol / L, preferably 0.005 to 0.01 mol / L.

[0029] Preferably, in step (1), the liquid-to-solid ratio of the alkaline solution to the solid material is 2-15 mL / g, more preferably 4-10 mL / g.

[0030] Preferably, in step (1), the inorganic base is at least one of sodium hydroxide, potassium hydroxide and ammonia water, preferably sodium hydroxide.

[0031] Preferably, in step (1), the temperature of the secondary reaction is higher than the temperature of the primary reaction.

[0032] Preferably, in step (1), the conditions for the primary reaction include: a temperature of 20–40°C and a time of 3–15 h.

[0033] Preferably, in step (1), the conditions for the secondary reaction include: a temperature of 60–120°C and a time of 6–30 h.

[0034] Preferably, in step (1), the amount of ZSM-23 seed crystals used is 0.1 to 8 parts by weight, more preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the solid material.

[0035] Preferably, in step (2), the molar ratio of the template agent b, the aluminum source (calculated as Al2O3), and the material obtained in step (1) (calculated as SiO2) is (0.01~0.1):(0.002~0.015):1, more preferably (0.02~0.08):(0.005~0.01):1.

[0036] Preferably, in step (2), the template agent b is one or any combination of at least two of pyrrolidine, isopropylamine, N,N-dimethylformamide, and dimethylamine.

[0037] Preferably, in step (2), the aluminum source is one or any combination of at least two of aluminum sulfate, aluminum isopropoxide, sodium aluminate and aluminum hydroxide.

[0038] Preferably, in step (2), the crystallization conditions include: a temperature of 180–220°C and a time of 24–72 h.

[0039] Preferably, in step (2), the drying conditions include a temperature of 80–120°C and a time of 6–12 hours.

[0040] Preferably, in step (2), the calcination conditions include: a temperature of 540–560°C and a time of 3–8 hours.

[0041] Preferably, in step (3), the ammonium exchange treatment can be carried out using conventional methods in the prior art. Specifically, in this invention, the ZSM-23 molecular sieve is placed in an ammonium salt (e.g., ammonium nitrate) solution with a concentration of 0.2–3.0 mol / L, wherein the liquid-to-solid ratio is 5–20 mL / g, and stirred continuously in a water bath at 60–100°C for 0.5–4 hours. The above process can be repeated multiple times until the content of alkali metal oxides (e.g., Na2O) in the ZSM-23 molecular sieve after ammonium exchange is less than 0.1 wt%. Then, washing, drying, and calcining are performed, wherein the drying temperature is 60–130°C, the drying time is 2–12 hours, preferably the drying temperature is 80–120°C, and the drying time is 4–8 hours; the calcination temperature is 500–600°C, the calcination time is 2–8 hours, preferably the calcination temperature is 530–570°C, and the calcination time is 3–6 hours.

[0042] Preferably, during the preparation of the carrier, the drying temperature is 60–130°C and the drying time is 2–12 hours, with a preferred drying temperature of 80–120°C and a drying time of 4–8 hours; the calcination temperature is 500–600°C and the calcination time is 2–8 hours, with a preferred calcination temperature of 530–570°C and a calcination time of 3–6 hours.

[0043] Preferably, during the preparation of the carrier, the molding aid is selected from one or more conventional molding aids in the prior art, such as nitric acid, guar gum powder, methylcellulose, and polyacrylamide, with nitric acid and / or guar gum powder being preferred.

[0044] Preferably, during the preparation of the carrier, the ratio of the amount of the molding aid added to the total mass of HZSM-23 molecular sieve and macroporous alumina is 0.005 to 0.1, more preferably 0.008 to 0.05.

[0045] Preferably, the loading of the metal active component can be carried out using conventional methods in the prior art, preferably by impregnation; after impregnation, the support is dried at 80-120°C for 4-12 hours, and then calcined at 400-700°C for 3-12 hours to obtain the oil hydrodeoxygenation catalyst.

[0046] The third aspect of this invention provides the application of the above-mentioned oil hydrodeoxygenation catalyst in the oil hydrodeoxygenation reaction process for preparing biodiesel.

[0047] In the application of this invention, the raw material is at least one of C10 to C20 saturated fatty acid glycerides.

[0048] In this invention, the operating conditions for the hydrodeoxygenation process of the oil are as follows: reaction temperature of 260–360°C, reaction pressure of 5.0–12.0 MPa, hydrogen-to-oil volume ratio of 600–1500, and liquid hourly space velocity of 0.1–2.0 h⁻¹. -1 .

[0049] In the catalyst preparation method provided by this invention, especially in the preparation method of ZSM-23 molecular sieve, an inexpensive template agent a is first selected to assist in the aging of silicon source to generate a hydrogel containing hydroxyl-rich primary structural unit silicon-oxygen tetrahedra and secondary structural units. After centrifugation, long-chain oleylamine molecules are added and bonded to the hydroxyl groups on the surface of the structural units in the gel through hydrogen bonds, and are arranged in an orderly and uniformly dispersed manner. Under the action of dilute alkaline solution, they dissociate into uniform structural fragments with specific channels, and then rapidly assemble into metastable ZSM-23 nanocrystals of pure silicon with the assistance of ZSM-23 seed crystals. The added Al species and template agent b form a chelate and combine with the hydroxyl groups on the surface of the metastable ZSM-23 nanocrystals. After high-temperature crystallization, a ZSM-23 molecular sieve with a stable structure and a surface rich in weak Brønsted acid sites is prepared.

[0050] When the catalyst prepared by combining HZSM-23 molecular sieve and β molecular sieve is used to produce biodiesel through hydrodeoxygenation of oils, the β molecular sieve in the catalyst can utilize its own acidic sites and pore structure to hydrodeoxygenate oils into long-chain alkanes. The generated long-chain alkanes are adsorbed on the outer surface and pore openings of ZSM-23 molecular sieve, which are rich in weak β-acid sites, and undergo isomerization reactions. This reduces the pour point while maintaining the cetane number, and its weak acidity avoids excessive cracking of the product, which can effectively improve the yield of biodiesel. Attached Figure Description

[0051] Figure 1 The image shows the XRD pattern of the HZSM-23 molecular sieve synthesized in Example 1 of this invention. Detailed Implementation

[0052] The technical solution of the present invention will be further illustrated below through embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0053] In this invention, "total Brønsted acid content in pyridine infrared spectroscopy" is used to represent the total Brønsted acid content in ZSM-23 molecular sieves, including Brønsted acid on the surface, at the pore openings, and within the pores. It is determined by pyridine adsorption infrared spectroscopy. The specific process is as follows: ZSM-23 molecular sieve samples are prepared into self-supporting wafers (5-6 mg / cm³). 2 The sample was placed in an in-situ cell and treated under vacuum at 400℃ for 4 hours, then cooled to 50℃, and spectra were collected. After adsorbing pyridine for 10 minutes, the sample was heated to 150℃ for desorption for 1 hour, cooled to room temperature, and spectra were collected. The total Brønsted acid content of pyridine was calculated. The Brønsted acid content was calculated according to the Lambert-Beer law, using a 1540 cm⁻¹ spectral depth. -1 The amount of Brønsted acid is calculated by measuring the area of ​​the absorption peak.

[0054] In this invention, "total Brønsted acid content of 2,6-dimethylpyridine infrared spectroscopy" is used to represent the amount of Brønsted acid distributed in the pores and surface of ZSM-23 molecular sieves, and "Brønsted acid content of 2,6-dimethylpyridine infrared spectroscopy at desorption temperature <250℃" is used to represent the amount of weak Brønsted acid distributed in the pores and surface of ZSM-23 molecular sieves. The determination is performed using 2,6-dimethylpyridine adsorption infrared spectroscopy. The specific process involves preparing the molecular sieve sample into a self-supporting wafer (5-6 mg / cm³). 2 The sample was placed in an in-situ cell and treated under vacuum at 400℃ for 4 hours, then cooled to 50℃, and spectra were collected. After adsorbing 2,6-dimethylpyridine for 10 minutes, the sample was heated to 150℃ for desorption for 1 hour, cooled to room temperature, and spectra were collected to calculate the total Brønsted acid content of 2,6-dimethylpyridine. The sample was then heated to 250℃ for desorption for 1 hour, cooled to room temperature, and spectra were collected to calculate the Brønsted acid content of 2,6-dimethylpyridine at desorption temperatures <250℃. The Brønsted acid content was calculated according to the Lambert-Beer law, using a 1630 cm⁻¹ spectral density. -1 1650cm -1 The amount of Brønsted acid is calculated by measuring the area of ​​the absorption peak.

[0055] In this invention, the bulk SiO2 / Al2O3 (molar ratio) is calculated based on X-ray fluorescence spectroscopy (XRF) analysis results. 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 20 s, and the optical path atmosphere being vacuum.

[0056] In this invention, the SiO2 / Al2O3 molar ratio on the outer surface was calculated based on X-ray photoelectron spectroscopy (XPS) analysis results. The elemental composition and state of the catalyst surface were determined using a Thermofisher Multilab 2000 electron spectrometer, with Mg Kα as the excitation source and a cathode voltage and current of 13 kV and 20 mA, respectively. The electron binding energy was calibrated using C1s (284.6 eV).

[0057] In this invention, XRD characterization was performed using a Dmax2500 X-ray diffractometer manufactured by Rigaku Corporation of Japan to collect the XRD patterns of the samples. The acquisition conditions were as follows: voltage 40 kV, current 80 mA, CuKα target, and incident wavelength 0.15405 nm.

[0058] Example 1

[0059] (1) Preparation of HZSM-23 molecular sieve

[0060] 4.68 g of hexamethylenediamine was dissolved in 54 g of deionized water, and then 6 g of fumed silica was added. After stirring at room temperature (25 °C) for 1 h, the mixture was transferred to a 100 mL reactor with a polytetrafluoroethylene liner. The mixture was crystallized at 150 °C for 24 h, then quenched and centrifuged to obtain 6.43 g of solid material.

[0061] Add 10 mL of oleylamine to the solid material, mix thoroughly in a shaker, and stir at room temperature for 0.5 h at a stirring rate of 200 rpm. Then add 42 mL of 0.008 mol / L NaOH solution to the mixture and carry out a first reaction at 25 °C with stirring for 6 h at a stirring rate of 200 rpm to obtain mixture A. Add 0.18 g of ZSM-23 seed crystals to deionized water to prepare 10 mL of ZSM-23 seed crystal solution, add it to mixture A, and carry out a second reaction at 80 °C with stirring for 16 h at a stirring rate of 300 rpm to obtain material B.

[0062] 0.67 g of Al2(SO4)3·18H2O and 0.40 g of pyrrolidine were added sequentially to 20 mL of deionized water to obtain a clear solution C. Solution C was added to the material B, and after thorough mixing, the final mixture was transferred to a 150 mL reactor lined with polytetrafluoroethylene and crystallized at 180 °C for 48 h. After crystallization, the mixture was filtered, washed, dried at 100 °C for 12 h, and then calcined at 550 °C for 4 h to obtain ZSM-23 molecular sieve Z-1.

[0063] Weigh the Z-1 sample and place it in a 1 mol / L ammonium nitrate solution with a liquid-to-solid ratio of 10 mL / g. Stir continuously in a water bath at 80–90 °C for 1 hour, then filter and wash. Repeat the above procedure twice. Dry the sample in a 100 °C oven for 8 hours, then calcine it in air at 550 °C for 3 hours to obtain HZ-1. Its XRD pattern is shown below. Figure 1 As shown, the specific properties are shown in Table 1.

[0064] (2) Catalyst preparation

[0065] Macroporous alumina (specific surface area 412m²) accounting for 80 wt% of the final catalyst weight will be used. 2 / g, pore volume 0.94cm 3 / g), 10wt% HZ-1 molecular sieve, 9.5wt% β molecular sieve (SiO2 / Al2O3 molar ratio of 50, specific surface area of ​​547m²). 2 / g, pore volume is 0.48cm 3 A mixture of guar gum powder (1 wt% of the total weight of alumina and molecular sieve) and a 1 wt% nitric acid aqueous solution was prepared, ground, and mixed with water. The mixture was then pressed into a paste and extruded into strips. The extruded strips were dried at 120°C for 4 hours and then calcined at 550°C for 3 hours to obtain a support strip. The support strip was added to a pre-prepared H₂PtCl₆ solution (equal in volume to the water absorption of the support) and deionized water. The mixture was allowed to stand for 12 hours, dried in air at 120°C for 4 hours, and then calcined at 450°C for 4 hours to obtain catalyst C-1. The catalyst contained 0.5 wt% Pt.

[0066] Example 2

[0067] (1) Preparation of HZSM-23 molecular sieve

[0068] 17.43 g of hexamethylenediamine was dissolved in 216 g of deionized water, and then 18 g of fumed silica was added. After stirring at room temperature (25 °C) for 1 h, the mixture was transferred to a 300 mL reactor with a polytetrafluoroethylene liner. The mixture was crystallized at 200 °C for 12 h, then quenched and centrifuged to obtain 18.97 g of solid material.

[0069] Add 37 mL of oleylamine to the solid material, mix thoroughly in a shaker, and stir at room temperature for 0.5 h at a stirring rate of 150 rpm. Then add 76 mL of 0.01 mol / L NaOH solution to the mixture and carry out a first reaction at 25 °C with stirring for 12 h at a stirring rate of 150 rpm to obtain mixture A. Add 0.9 g of ZSM-23 seed crystals to deionized water to prepare 30 mL of ZSM-23 seed crystal solution, add it to mixture A, and carry out a second reaction at 100 °C with stirring for 20 h at a stirring rate of 300 rpm to obtain material B.

[0070] 0.67 g of Al2(SO4)3·18H2O and 0.85 g of pyrrolidine were added sequentially to 20 mL of deionized water to obtain a clear solution C. Solution C was added to the material B, and after thorough mixing, the final mixture was transferred to a 200 mL reactor lined with polytetrafluoroethylene and crystallized at 200 °C for 36 h. After crystallization, the mixture was filtered, washed, dried at 100 °C for 12 h, and then calcined at 550 °C for 4 h to obtain ZSM-23 molecular sieve Z-2.

[0071] The sample was placed in a 0.5 mol / L ammonium nitrate solution with a liquid-to-solid ratio of 50 mL / g and stirred continuously in a water bath at 80–90 °C for 1 h. After filtration and washing, the sample was repeated twice. The sample was then dried in a 100 °C oven for 8 h, followed by calcination at 550 °C in air for 3 h to obtain HZ-2. Its XRD pattern is similar to... Figure 1 Similarly, see Table 1 for specific properties.

[0072] (2) Catalyst preparation

[0073] Macroporous alumina (specific surface area 412m²) accounting for 80 wt% of the final catalyst weight will be used. 2 / g, pore volume 0.94cm 3 / g), 7.5wt% HZ-2 molecular sieve, 12wt% β molecular sieve (SiO2 / Al2O3 molar ratio of 50, specific surface area of ​​547m²), 2 / g, pore volume is 0.48cm 3 A mixture of guar gum powder (1 wt% of the total weight of alumina and molecular sieve) and a 1 wt% nitric acid aqueous solution was prepared, ground, and mixed with water. The mixture was then pressed into a paste and extruded into strips. The extruded strips were dried at 120°C for 4 hours and then calcined at 550°C for 3 hours to obtain a support strip. The support strip was added to a pre-prepared H₂PtCl₆ solution (equal in volume to the water absorption of the support) and deionized water. The mixture was allowed to stand for 12 hours, dried in air at 120°C for 4 hours, and then calcined at 450°C for 4 hours to obtain catalyst C-2. The catalyst contained 0.5 wt% Pt.

[0074] Example 3

[0075] (1) Preparation of HZSM-23 molecular sieve

[0076] 4.68 g of hexamethylenediamine was dissolved in 54 g of deionized water, and then 6 g of fumed silica was added. After stirring at room temperature (25 °C) for 1 h, the mixture was transferred to a 100 mL reactor with a polytetrafluoroethylene liner. The mixture was crystallized at 170 °C for 24 h, then quenched and centrifuged to obtain 6.34 g of solid material.

[0077] Add 6 mL of oleylamine to the solid material, mix thoroughly in a shaker, and stir at room temperature for 0.5 h at a stirring rate of 200 rpm. Then add 63 mL of 0.005 mol / L NaOH solution to the mixture and carry out a first reaction at 25 °C with stirring for 6 h at a stirring rate of 200 rpm to obtain mixture A. Add 0.18 g of ZSM-23 seed crystals to deionized water to prepare 10 mL of ZSM-23 seed crystal solution, add it to mixture A, and carry out a second reaction at 80 °C with stirring for 16 h at a stirring rate of 200 rpm to obtain material B.

[0078] 0.17 g of Al2(SO4)3·18H2O and 0.40 g of pyrrolidine were added sequentially to 20 mL of deionized water to obtain a clear solution C. Solution C was added to the material B, and after thorough mixing, the final mixture was transferred to a 150 mL reactor lined with polytetrafluoroethylene and crystallized at 200 °C for 48 h. After crystallization, the mixture was filtered, washed, dried at 100 °C for 12 h, and then calcined at 550 °C for 4 h to obtain ZSM-23 molecular sieve Z-3.

[0079] Weigh the Z-3 sample and place it in a 2 mol / L ammonium nitrate solution with a liquid-to-solid ratio of 20 mL / g. Stir continuously in a water bath at 80–90 °C for 1 hour, then filter and wash. Repeat the above procedure twice. Dry the sample in a 100 °C oven for 8 hours, then calcine it in air at 550 °C for 3 hours to obtain HZ-3. Its XRD pattern is similar to... Figure 1 Similarly, see Table 1 for specific properties.

[0080] (2) Catalyst preparation

[0081] Macroporous alumina (specific surface area 412m²) accounting for 80 wt% of the final catalyst weight will be used. 2 / g, pore volume 0.94cm 3 / g), 10wt% HZ-3 molecular sieve, 9.5wt% β molecular sieve (SiO2 / Al2O3 molar ratio of 50, specific surface area of ​​547m²). 2 / g, pore volume is 0.48cm 3 A mixture of guar gum powder (1 wt% of the total weight of alumina and molecular sieve) and a 1 wt% nitric acid aqueous solution was prepared, ground, and mixed with water. The mixture was then pressed into a paste and extruded into strips. The extruded strips were dried at 120°C for 4 hours and then calcined at 550°C for 3 hours to obtain a support strip. The support strip was added to a pre-prepared H₂PtCl₆ solution (equal in volume to the water absorption of the support) and deionized water. The mixture was allowed to stand for 12 hours, dried in air at 120°C for 4 hours, and then calcined at 450°C for 4 hours to obtain catalyst C-3. The catalyst contained 0.5 wt% Pt.

[0082] Example 4

[0083] (1) Preparation of HZSM-23 molecular sieve

[0084] 4.68 g of hexamethylenediamine was dissolved in 54 g of deionized water, and then 6 g of fumed silica was added. After stirring at room temperature (25 °C) for 1 h, the mixture was transferred to a 100 mL reactor with a polytetrafluoroethylene liner. The mixture was crystallized at 150 °C for 24 h, then quenched and centrifuged to obtain 6.61 g of solid material.

[0085] Add 3.3 mL of oleylamine to the solid material, mix thoroughly in a shaker, and stir at room temperature for 0.5 h at a stirring rate of 250 rpm. Then add 30 mL of 0.008 mol / L NaOH solution to the mixture and carry out a first reaction at 25 °C with stirring for 8 h at a stirring rate of 250 rpm to obtain mixture A. Add 0.03 g of ZSM-23 seed crystals to deionized water to prepare 5 mL of ZSM-23 seed crystal solution, add it to mixture A, and carry out a second reaction at 60 °C with stirring for 30 h at a stirring rate of 200 rpm to obtain material B.

[0086] 0.44 g of Al2(SO4)3·18H2O and 0.15 g of pyrrolidine were added sequentially to 15 mL of deionized water to obtain a clear solution C. Solution C was added to the material B, and after thorough mixing, the final mixture was transferred to a 100 mL reactor lined with polytetrafluoroethylene and crystallized at 180 °C for 24 h. After crystallization, the mixture was filtered, washed, dried at 100 °C for 12 h, and then calcined at 550 °C for 4 h to obtain ZSM-23 molecular sieve Z-4.

[0087] Weigh the Z-4 ​​sample and place it in a 2 mol / L ammonium nitrate solution with a liquid-to-solid ratio of 10 mL / g. Stir continuously in a water bath at 80–90 °C for 1 hour, then filter and wash. Repeat the above procedure twice. Dry the sample in a 100 °C oven for 8 hours, then calcine it in air at 550 °C for 3 hours to obtain HZ-4. Its XRD pattern is similar to... Figure 1 Similarly, see Table 1 for specific properties.

[0088] (2) Catalyst preparation

[0089] Macroporous alumina (specific surface area 412m²) accounting for 75 wt% of the final catalyst weight will be used. 2 / g, pore volume 0.94cm 3 / g), 12wt% HZ-4 molecular sieve, 12.5wt% β molecular sieve (SiO2 / Al2O3 molar ratio of 50, specific surface area of ​​547m²). 2 / g, pore volume is 0.48cm 3A mixture of guar gum powder (1 wt% of the total weight of alumina and molecular sieve) and a 1 wt% nitric acid aqueous solution was prepared, ground, and mixed with water. The mixture was then pressed into a paste and extruded into strips. The extruded strips were dried at 120°C for 4 hours and then calcined at 550°C for 3 hours to obtain a support strip. The support strip was added to a pre-prepared H₂PtCl₆ solution (equal in volume to the water absorption of the support) and deionized water. The mixture was allowed to stand for 12 hours, dried in air at 120°C for 4 hours, and then calcined at 450°C for 4 hours to obtain catalyst C-1. The catalyst contained 0.5 wt% Pt.

[0090] Comparative Example 1

[0091] (1) Preparation of HZSM-23 molecular sieve according to patent CN109516471A

[0092] 0.079 g NaOH, 0.163 g Al2(SO4)3·18H2O, 0.438 g pyrrolidine, and 1.48 g fumed silica were sequentially dissolved in 20.0 g deionized water and thoroughly mixed to obtain gel A. The molar ratio of each component was SiO2 in the silicon source: Al2O3 in the aluminum source: PY: NaOH: H2O = 1:0.01:0.25:0.083:45. Gel A was heated in a 180℃ constant temperature oven for 12 h and then cooled to room temperature. 0.119 g NaOH, 0.489 g... Al2(SO4)3·18H2O and 2.22g of fumed silica were dissolved sequentially in 30.0g of deionized water and stirred until homogeneous to obtain gel B. The molar ratio of the components was SiO2 in the silicon source: Al2O3 in the aluminum source: NaOH:H2O = 1:0.02:0.083:45. Gel B was added to gel A and mechanically stirred for 1h to obtain a uniform white gel. This gel was transferred to a 100mL hydrothermal reactor and crystallized at 180℃ for 44h. The resulting product was then filtered, washed, and dried at 65℃ for 24h to obtain ZSM-23 molecular sieve DZ-1.

[0093] Weigh the DZ-1 sample and place it in a 2 mol / L ammonium nitrate solution with a liquid-to-solid ratio of 10. Stir continuously in a water bath at 80–90 °C for 1 hour, then filter and wash. Repeat the above operation twice, then dry the sample in a 100 °C oven for 8 hours, and then calcine it in air at 550 °C for 3 hours to obtain HDZ-1. The specific properties are shown in Table 1.

[0094] (2) Catalyst preparation

[0095] Macroporous alumina (specific surface area 412m²) accounting for 80 wt% of the final catalyst weight will be used. 2 / g, pore volume 0.94cm 3 / g), 10wt% HDZ-1 molecular sieve, 9.5wt% β molecular sieve (SiO2 / Al2O3 molar ratio of 50, specific surface area of ​​547m²). 2 / g, pore volume is 0.48cm 3 A mixture of guar gum powder (1 wt% of the total weight of alumina and molecular sieve) and a 1 wt% nitric acid aqueous solution was prepared, ground, and mixed with water. The mixture was then pressed into a paste and extruded into strips. The extruded strips were dried at 120°C for 4 hours and then calcined at 550°C for 3 hours to obtain a support strip. The support strip was added to a pre-prepared H₂PtCl₆ solution (equal in volume to the water absorption of the support) and deionized water. The mixture was allowed to stand for 12 hours, dried in air at 120°C for 4 hours, and then calcined at 450°C for 4 hours to obtain catalyst DC-1. The catalyst contained 0.5 wt% Pt.

[0096] Comparative Example 2

[0097] Compared with Example 1, the difference is that oleylamine was not added during the preparation of HZSM-23 molecular sieve, while the other conditions were the same as in Example 1. The HZSM-23 molecular sieve is HDZ-2, and its specific properties are shown in Table 1; the corresponding catalyst obtained is DC-2.

[0098] Table 1. Properties of the molecular sieves obtained in each example and comparative example.

[0099]

[0100] Application examples

[0101] The hydrodeoxygenation performance of catalysts C-1, C-2, C-3, and C-4 of this invention, and comparative catalysts DC-1 and DC-2, was evaluated in a fixed-bed reactor. The reactants consisted of 40 wt% glyceryl stearate and 60 wt% decahydronaphthalene. Before the reaction, the catalysts were reduced in a hydrogen atmosphere at 400°C for 8 h. The reaction temperature was 320°C, the reaction pressure was 8 MPa, the hydrogen-to-oil volume ratio was 800, and the liquid hourly space velocity was 1.0 h⁻¹. -1 The reaction results are shown in Table 2.

[0102] Table 2 shows the reaction performance results of the catalysts obtained in each example and comparative example.

[0103]

[0104] As can be seen from the reaction results in Table 2, under the same process conditions, the catalyst described in this invention has a better ability to hydrogenate and deoxygenate oils than the reference catalyst, and the product contains more long-chain isoalkanes, which promotes the improvement of low-temperature flow properties.

Claims

1. A catalyst for the hydrodeoxygenation of oils and fats, comprising the following components based on the weight of the final catalyst: a) HZSM-23 molecular sieve, with a content of 3-15 wt%, preferably 5-12 wt%; b) β molecular sieve, with a content of 5-20 wt%, preferably 8-15 wt%; c) Macroporous alumina, with a content of 65-85 wt%, preferably 70-82 wt%; d) The content of the noble metal active component, calculated as an element, is 0.05 to 5.0 wt%, preferably 0.1 to 3.5 wt%; in, The bulk SiO2 / Al2O3 molar ratio of the HZSM-23 molecular sieve is 40 to 400 higher than that of the outer surface SiO2 / Al2O3 molar ratio.

2. The oil hydrodeoxygenation catalyst according to claim 1, characterized in that, The noble metal active component is at least one of Re, Pt, Pd, Ru, and Rh, preferably Pd and / or Pt.

3. The oil hydrodeoxygenation catalyst according to claim 1, characterized in that, The bulk SiO2 / Al2O3 molar ratio of the HZSM-23 molecular sieve is 70–500, and the outer surface SiO2 / Al2O3 molar ratio is 40–120; preferably, the bulk SiO2 / Al2O3 molar ratio of the HZSM-23 molecular sieve is 80–400, and the outer surface SiO2 / Al2O3 molar ratio is 45–90.

4. The oil hydrodeoxygenation catalyst according to claim 1, characterized in that, The ratio of the total Brønsted acid content of 2,6-dimethylpyridine infrared radiation to the total Brønsted acid content of pyridine infrared radiation in the HZSM-23 molecular sieve is 65-96:100, preferably 69-93:100; at the same time, the ratio of the Brønsted acid content of 2,6-dimethylpyridine infrared radiation to the total Brønsted acid content of 2,6-dimethylpyridine infrared radiation at a desorption temperature <250℃ is 67-95:100, preferably 70-92:

100. And / or, the total Brønsted acid content of pyridine in the HZSM-23 molecular sieve is 0.12–0.40 mmol / g, preferably 0.14–0.38 mmol / g; the total Brønsted acid content of 2,6-dimethylpyridine in the HZSM-23 molecular sieve is 0.09–0.40 mmol / g, preferably 0.11–0.33 mmol / g, and the Brønsted acid content of 2,6-dimethylpyridine in the HZSM-23 molecular sieve with a desorption temperature <250℃ is 0.07–0.29 mmol / g, preferably 0.08–0.20 mmol / g.

5. The oil hydrodeoxygenation catalyst according to claim 1, characterized in that, The properties of the β-zeolite are as follows: SiO2 / Al2O3 molar ratio of 40–60, specific surface area of ​​500–700 m² / g. 2 / g, pore volume 0.35~0.50cm³ 3 / g; And / or, the macroporous alumina has the following properties: specific surface area of ​​375–450 m² / g. 2 / g, pore volume 0.74~1.15cm 3 / g; preferably, specific surface area is 390-430m² 2 / g, pore volume 0.78~1.10cm 3 / g.

6. The method for preparing the oil hydrodeoxygenation catalyst according to any one of claims 1-5 includes the preparation of a catalyst support and the loading of an active metal; wherein HZSM-23 molecular sieve, β molecular sieve, macroporous alumina and molding aid are mixed, shaped, dried and calcined to obtain the catalyst support.

7. The preparation method according to claim 6, characterized in that, The preparation method of the HZSM-23 molecular sieve includes: (1) A mixture of silicon source, template agent a and water is subjected to a crystallization reaction, and a solid material is separated from the reacted material; the solid material, aliphatic amine and inorganic base are mixed and reacted once, and then ZSM-23 seed crystals are added and reacted twice to obtain the reacted material; (2) Mix the aluminum source, template agent b and the material obtained in step (1), and then crystallize, filter, wash, dry and calcine in sequence to obtain ZSM-23 molecular sieve; (3) The ZSM-23 molecular sieve obtained in step (2) is subjected to ammonium exchange treatment to obtain HZSM-23 molecular sieve.

8. The preparation method according to claim 7, characterized in that, In step (1), the silicon source is one or any combination of at least two of the following: silica, silica sol, water glass, fumed silica and tetraethyl orthosilicate. And / or, in step (1), the template agent a is one or any combination of at least two of hexamethylenediamine, n-hexamethyleneamine, ethanol, tetrapropylammonium hydroxide, tetrapropylammonium bromide and triethylamine; And / or, in step (1), the fatty amine is a C12-C18 fatty amine, preferably at least one of oleylamine, octadecylamine and dodecylamine; And / or, in step (1), the inorganic base is at least one of sodium hydroxide, potassium hydroxide and ammonia water.

9. The preparation method according to claim 7, characterized in that, In step (1), the liquid-to-solid ratio of the fatty amine to the solid material is 0.3–3 mL / g; in step (1), the liquid-to-solid ratio of the alkaline solution to the solid material is 2–15 mL / g. And / or, in step (1), the inorganic base is used in the form of an alkaline solution with a concentration of 0.003 to 0.015 mol / L; And / or, in step (1), the amount of ZSM-23 seed crystals used is 0.1-8 parts by weight relative to 100 parts by weight of the solid material.

10. The preparation method according to claim 7, characterized in that, In step (1), the conditions for the crystallization reaction include: a temperature of 120–220°C and a time of 8–48 h; And / or, in step (1), the conditions for the primary reaction include: a temperature of 20–40°C and a time of 3–15 h; And / or, in step (1), the conditions for the secondary reaction include: a temperature of 60 to 120°C and a time of 6 to 30 hours.

11. The preparation method according to claim 7, characterized in that, In step (2), the molar ratio of the template agent b, the aluminum source (calculated as Al2O3), and the material obtained in step (1) (calculated as SiO2) is (0.01~0.1):(0.002~0.015):1; And / or, in step (2), the template agent b is one or any combination of at least two of pyrrolidine, isopropylamine, N,N-dimethylformamide, and dimethylamine; And / or, in step (2), the aluminum source is one or any combination of at least two of aluminum sulfate, aluminum isopropoxide, sodium aluminate and aluminum hydroxide.

12. The preparation method according to claim 7, characterized in that, In step (2), the crystallization conditions include: a temperature of 180–220°C and a time of 24–72 h; And / or, in step (2), the drying conditions include: a temperature of 80–120°C and a time of 6–12 h; And / or, in step (2), the calcination conditions include: a temperature of 540–560°C and a time of 3–8 h.

13. The preparation method according to claim 7, characterized in that, In step (3), the specific method of the ammonium exchange treatment is as follows: ZSM-23 molecular sieve is placed in an ammonium salt solution with a concentration of 0.2 to 3.0 mol / L, wherein the liquid-to-solid ratio is 5 to 20 mL / g, and stirred continuously in a water bath at 60 to 100°C for 0.5 to 4 hours. The above process can be repeated multiple times until the content of alkali metal oxides in the ZSM-23 molecular sieve after ammonium exchange is less than 0.1 wt%. Then, it is washed, dried, and calcined, wherein the drying temperature is 60 to 130°C and the drying time is 2 to 12 hours; the calcination temperature is 500 to 600°C and the calcination time is 2 to 8 hours.

14. The preparation method according to claim 6, characterized in that, During the preparation of the carrier, the drying temperature is 60-130℃ and the drying time is 2-12 hours; the calcination temperature is 500-600℃ and the calcination time is 2-8 hours.

15. The preparation method according to claim 6, characterized in that, The method for loading the active component is impregnation; after impregnation, the support is dried at 80-120℃ for 4-12 hours, and then calcined at 400-700℃ for 3-12 hours to obtain the final catalyst.

16. The application of the oil hydrodeoxygenation catalyst according to any one of claims 1-5 in the oil hydrodeoxygenation reaction process to prepare biodiesel.

17. The application according to claim 16, characterized in that, The raw material is at least one of C10 to C20 saturated fatty acid glycerides.

18. The application according to claim 16, characterized in that, The operating conditions for the hydrodeoxygenation process of the oil are as follows: reaction temperature 260–360℃, reaction pressure 5.0–12.0 MPa, hydrogen-to-oil volume ratio 600–1500, and liquid hourly space velocity 0.1–2.0 h⁻¹. -1 .

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