Grease hydrogenation catalyst and preparation method thereof

Abstract

The invention provides a grease hydrogenation catalyst and a preparation method thereof, and relates to the field of catalyst preparation, the preparation method comprises the following steps: preparing unit cell distortion pseudo-boehmite; the method comprises the following steps: impregnating unit cell distorted pseudo-boehmite with a nickel-containing solution I to obtain an impregnated material I, adding an alkaline solution I into the impregnated material I to carry out first precipitation treatment, filtering, washing and drying the precipitated material, impregnating with a nickel-containing solution II to obtain an impregnated material II, adding an alkaline solution II into the impregnated material II to carry out second precipitation treatment to obtain a nickel-containing material II; filtering, washing, drying and roasting the precipitated material to obtain nickel-containing aluminum oxide; reducing the nickel-containing aluminum oxide to prepare the grease hydrogenation catalyst; according to the method, unit cell distorted pseudo-boehmite is taken as a raw material, the prepared grease hydrogenation catalyst has abundant surface defects and also has open pore channels beneficial to mass transfer and diffusion of reactants and hydrogenation products, the active component nickel is uniformly dispersed on the surface of the catalyst, and the hydrogenation activity is high.

Description

Technical Field

[0001] The present application relates to the field of catalyst preparation, and specifically to a fat hydrogenation catalyst and a preparation method thereof. Background Art

[0002] Oil hydrogenation is the process by which unsaturated C=C double bonds in oils and fats react with hydrogen in the presence of a catalyst, saturating the double bonds. Oil hydrogenation can effectively increase the melting point, thermal stability, and antioxidant capacity of oils and fats, while improving their color, odor, and flavor. It is an effective means of oil modification, and the resulting hydrogenated oil has significant economic value and market demand. With the development of oil hydrogenation, research on oil hydrogenation catalysts has also gained increasing attention. Ni / Al2O3 catalysts, prepared with nickel as the active component and alumina as the carrier, are widely used in the oil processing industry.

[0003] Patent application number CN200610016260.3 discloses a method for preparing an unsaturated oil hydrogenation catalyst. The catalyst preparation steps are as follows: placing an alkaline precipitant solution into a reactor and heating it to 60-70°C. A mixed solution of soluble nickel and iron salts is added to the solution while stirring within 1-2 hours. After the addition is complete, an alumina carrier is quickly added and stirred for 0.5-1 hour. The mixture is filtered and washed with deionized water until free of acid ions. The catalyst is then dried at 110-120°C for 4-5 hours, crushed, and reduced with hydrogen at 400-500°C for 2-3 hours to obtain the finished catalyst.

[0004] Patent application number CN201310472517.6 discloses a method for preparing an unsaturated oil hydrogenation catalyst. The catalyst preparation steps are as follows: first, a stable carrier alumina sol is prepared under stirring at a certain temperature. Then, an acidic solution containing a nickel salt and an alkaline precipitant are added to this solution in parallel. The resulting precipitate is washed, dried, and then reduced at high temperature to obtain a nickel oil hydrogenation catalyst.

[0005] The oil hydrogenation catalyst prepared by the above method has the following deficiencies: (1) the catalyst pores are small, which is not conducive to the mass transfer and diffusion of reactants and hydrogenation products; (2) the metal nickel is unevenly distributed on the catalyst surface, which affects the activity of the catalyst; (3) there are few defects in the catalyst, which is not conducive to the improvement of the catalyst activity. Summary of the Invention

[0006] In order to solve one of the above technical defects, the present application provides a fat hydrogenation catalyst and a preparation method thereof.

[0007] According to a first aspect of the present application, a method for preparing a fat hydrogenation catalyst is provided, comprising the following steps:

[0008] (1) Preparation of unit cell distorted pseudo-boehmite;

[0009] (2) impregnating the unit cell distorted pseudo-boehmite prepared in step (1) with a nickel-containing solution I to obtain an impregnated material I, adding an alkaline solution I to the impregnated material I for a first precipitation treatment, wherein the mass ratio of the impregnated material I to the alkaline solution I is 5:1-10:1, filtering, washing, and first drying the precipitated material, and then impregnating it with a nickel-containing solution II to obtain an impregnated material II, adding an alkaline solution II to the impregnated material II for a second precipitation treatment, wherein the mass ratio of the impregnated material II to the alkaline solution II is 5:1-10:1, filtering, washing, second drying, and first roasting the precipitated material to obtain nickel-containing alumina;

[0010] (3) Reducing the nickel-containing alumina obtained in step (2) to obtain a fat hydrogenation catalyst.

[0011] Preferably, in the step (1), the unit cell distorted pseudo-boehmite is prepared, which specifically includes the following steps: performing a second roasting on aluminum nitrate to obtain an amorphous aluminum oxide compound, crushing the obtained amorphous aluminum oxide compound and placing it in an autoclave, adding urea solution to the autoclave, wherein the mass ratio of the amorphous aluminum oxide compound to the urea solution is 1:2 to 1:10, mixing them uniformly, and then sequentially performing a low-temperature hydrothermal treatment and a high-temperature hydrothermal treatment on the mixed material, filtering, washing, and drying the material after the two hydrothermal treatments to obtain the unit cell distorted pseudo-boehmite.

[0012] Preferably, in the preparation method of the unit cell distorted pseudo-boehmite, the second calcination temperature is 450-600°C, the second calcination time is 4-8h, the particle size of the amorphous aluminum oxide compound after crushing treatment is less than 20μm, the concentration of urea in the urea solution is 11.5wt%-18.5wt%, the temperature of the low-temperature hydrothermal treatment is 90-130°C, the time of the low-temperature hydrothermal treatment is 1-4h, the temperature of the high-temperature hydrothermal treatment is 150-200°C, the time of the high-temperature hydrothermal treatment is 10-16h, the third drying temperature is 100-160°C, and the third drying time is 6-10h.

[0013] Preferably, in step (1), the unit cell distorted pseudo-boehmite has a petal cluster morphology, the petal cluster particles are composed of a plurality of lamellar particle clusters, the petal cluster particles have a size of 3-6 μm, the lamellar particles have a size of 0.3-0.8 μm, the length to width ratio of the lamellar is 3:1-6:1, and the lamellar thickness is 25-45 nm; the (020) crystal plane spacing of the unit cell distorted pseudo-boehmite is reduced by a percentage of 0.6%-1.9% compared with the (020) crystal plane spacing of SB powder.

[0014] Preferably, in step (3), the nickel-containing aluminum oxide obtained in step (2) is reduced to obtain a fat hydrogenation catalyst, specifically comprising:

[0015] The nickel-containing alumina obtained in step (2) is placed in a reduction reactor, and a mixed gas of nitrogen and hydrogen is introduced into the reduction reactor to reduce the nickel-containing alumina to obtain a fat hydrogenation catalyst; wherein the reduction temperature is 450-550°C, the reduction time is 4-8 hours, and the volume ratio of nitrogen to hydrogen in the mixed gas is 4:1-2:1.

[0016] Preferably, in step (2), the first precipitation time or the second precipitation time is 4-8 hours, the first drying temperature is 100-160°C, the first drying time is 4-10 hours, the second drying temperature is 100-160°C, the second drying time is 4-10 hours, the first roasting temperature is 450-550°C, and the first roasting time is 6-10 hours.

[0017] Preferably, in step (2), the nickel-containing solution I or the nickel-containing solution II is one or more of nickel acetate, nickel nitrate, nickel sulfate, nickel phosphate, and nickel carbonate; and the nickel content in the nickel-containing solution I or the nickel-containing solution II is 5.5 wt%-15.5 wt%.

[0018] Preferably, in step (2), alkaline solution I or alkaline solution II is one or more of sodium carbonate, sodium bicarbonate, and sodium hydroxide.

[0019] Preferably, the pH value of the alkaline solution I or alkaline solution II is 8-9.5.

[0020] According to a second aspect of the present application, a fat hydrogenation catalyst is provided, which is prepared according to any of the above methods for preparing the fat hydrogenation catalyst.

[0021] The present application provides a method for preparing a fat hydrogenation catalyst, which, compared to existing technologies, has the following technical effects: The fat hydrogenation catalyst prepared using distorted unit cell pseudo-boehmite as raw material has a high surface defect content, which is beneficial for improving the activity of the fat hydrogenation catalyst. Furthermore, the distorted unit cell pseudo-boehmite particles have a petal-like cluster structure, which is composed of clusters of lamellar particles. The accumulation of the lamellar particles forms open channels of 50-100 nm. During the hydrogenation reaction, the reaction raw materials and hydrogenation products can be improved in the catalyst for mass transfer and diffusion, effectively increasing the number and utilization rate of active sites on the catalyst surface. When loading active metals, the nickel-containing solution is first adsorbed onto the surface of the unit cell distorted pseudo-boehmite lamellar particles and the macropores, and then immersed in an alkaline solution to allow the adsorbed nickel salt to slowly react with the alkaline substance to precipitate. The formed precipitate is evenly loaded onto the catalyst surface, and the precipitation treatment is carried out in at least two steps. While increasing the nickel loading amount, the dispersion of nickel on the catalyst surface is also improved, so that the prepared oil hydrogenation catalyst has a higher hydrogenation activity.

[0022] Other features and advantages of the present application will be described in the following description, and in part will become apparent from the description, or will be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the contents indicated in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0024] Figure 1 This is an SEM image of the unit cell distorted pseudo-boehmite prepared in Example 1;

[0025] Figure 2 XRD spectra of SB powder, unit cell distorted pseudo-boehmite prepared in Example 1, and SB powder;

[0026] Figure 3 This is a SEM image of the amorphous aluminum oxide compound provided in Example 5 of the present application;

[0027] Figure 4 This is an SEM image of the unit cell distorted pseudo-boehmite provided in Example 5 of the present application;

[0028] Figure 5 The SEM image of pseudo-boehmite provided in Comparative Example 4 of this application;

[0029] Figure 6 The SEM image of pseudo-boehmite provided in Comparative Example 5 of this application;

[0030] Figure 7 This is an SEM image of pseudo-boehmite provided in Comparative Example 6 of this application;

[0031] Figure 8 The XRD spectrum of the amorphous aluminum oxide compound provided in Example 5 of the present application;

[0032] Figure 9 This is the XRD spectrum of SB powder and the unit cell distorted pseudo-boehmite provided in Example 5 of the present application. DETAILED DESCRIPTION

[0033] In order to make the technical solutions and advantages of the embodiments of the present application more clearly understood, the exemplary embodiments of the present application are further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present application, and are not an exhaustive list of all the embodiments. It should be noted that the embodiments and features in the embodiments of the present application can be combined with each other unless they conflict.

[0034] Unless otherwise specified, the reagents and materials used in the examples are commercially available. The testing methods used in the following examples are all conventional methods in the art, unless otherwise noted. In this application, wt% represents mass fraction. SB (sasol boehmite) powder is a high-quality, high-purity pseudo-boehmite developed by Sasol, Germany, using high-purity aluminum and higher alcohols as raw materials.

[0035] Sample microstructure characterization: Scanning electron microscopy (SEM) was used to characterize the sample microstructure.

[0036] Characterization of sample phase structure: X-ray diffractometer is used to characterize the sample phase structure.

[0037] The iodine values ​​of reactants and products were determined according to GB / T 5532-2008.

[0038] The formula for calculating the percentage reduction in interplanar spacing, δ, is: δ = (d1 - d2) / d1; where d1 is the (020) interplanar spacing of the SB powder, and d2 is the (020) interplanar spacing of the prepared sample. The (020) plane corresponds to the characteristic peak at 2θ of 11.1°-17.5° in the XRD spectrum. The interplanar spacing of the SB powder and the prepared sample is calculated using Bragg's law: nλ = 2d.sinθ, where n is an integer representing the diffraction order; λ is the wavelength of the incident X-ray; and θ is the diffraction angle, i.e., the angle between the incident beam and the interplanar plane.

[0039] In response to some problems existing in the prior art, the present application provides a method for preparing a fat hydrogenation catalyst, comprising the following steps:

[0040] (1) Preparation of unit cell distorted pseudo-boehmite;

[0041] (2) impregnating the unit cell distorted pseudo-boehmite prepared in step (1) with nickel-containing solution I to obtain impregnated material I, wherein the amount of nickel-containing solution I is such that the unit cell distorted pseudo-boehmite is adsorbed saturated, adding alkaline solution I to impregnated material I for a first precipitation treatment, filtering, washing, and first drying the precipitated material, and then impregnating with nickel-containing solution II to obtain impregnated material II, wherein the amount of nickel-containing solution II is such that the material after the first drying is adsorbed saturated, adding alkaline solution II to impregnated material II for a second precipitation treatment, filtering, washing, second drying, and first roasting the precipitated material, and obtaining nickel-containing alumina; wherein the mass ratio of impregnated material I to alkaline solution I is 5:1-10:1, and the mass ratio of impregnated material II to alkaline solution II is 5:1-10:1. The nickel-containing solution I or II is one or more of nickel acetate, nickel nitrate, nickel sulfate, nickel phosphate, and nickel carbonate, and the nickel content in the nickel-containing solution I or II is 5.5wt%-15.5wt%; the alkaline solution I or II is one or more of sodium carbonate, sodium bicarbonate, and sodium hydroxide, and the pH value of the alkaline solution I or II is 8-9.5;

[0042] (3) placing the nickel-containing alumina obtained in step (2) in a reduction reactor, and introducing a mixed gas of nitrogen and hydrogen in a certain volume ratio into the reduction reactor, adjusting the reduction temperature and reduction time of the reduction reactor, reducing the nickel-containing alumina to obtain a fat hydrogenation catalyst; wherein the reduction temperature is 450-550°C, the reduction time is 4-8h, and the volume ratio of nitrogen to hydrogen in the mixed gas is 4:1-2:1.

[0043] In a specific implementation, the precipitation treatment process in step (2) is performed at least twice, that is, the unit cell distorted pseudo-boehmite that has absorbed the nickel salt solution is immersed in an alkaline solution for precipitation treatment, i.e., a first precipitation; after the precipitation, the material is dried and then adsorbed with the nickel salt solution again, and the adsorbed material is immersed in an alkaline solution again for precipitation treatment, i.e., a second precipitation.

[0044] The present application provides a method for preparing a fat hydrogenation catalyst, which, compared to existing technologies, has the following technical effects: The fat hydrogenation catalyst prepared using distorted unit cell pseudo-boehmite as raw material has a high surface defect content, which is beneficial for improving the activity of the fat hydrogenation catalyst. Furthermore, the distorted unit cell pseudo-boehmite particles have a petal-like cluster structure, which is composed of clusters of lamellar particles. The accumulation of the lamellar particles forms open channels of 50-100 nm. During the hydrogenation reaction, the reaction raw materials and hydrogenation products can be improved in the catalyst for mass transfer and diffusion, effectively increasing the number and utilization rate of active sites on the catalyst surface. When loading active metals, the nickel-containing solution is first adsorbed onto the surface of the unit cell distorted pseudo-boehmite lamellar particles and the macropores, and then immersed in an alkaline solution to allow the adsorbed nickel salt to slowly react with the alkaline substance to precipitate. The formed precipitate is evenly loaded onto the catalyst surface, and the precipitation treatment is carried out in at least two steps. While increasing the nickel loading amount, the dispersion of nickel on the catalyst surface is also improved, so that the prepared oil hydrogenation catalyst has a higher hydrogenation activity.

[0045] In order to demonstrate the beneficial effects of the preparation method of the oil hydrogenation catalyst provided in this application, the present application is further described below in conjunction with specific examples. Among them, the oil hydrogenation catalysts Cat-1 to Cat-4 in Examples 1 to 4 and the comparative catalysts Cat-5 to Cat-7 in Comparative Examples 1 to 3 were prepared according to the addition ratios of the raw materials and the preparation conditions specified in Table 1 below. In addition to the above examples, this application also uses data within the range of other preparation conditions (such as the pH value of the alkaline solution, the precipitation treatment time, the various conditions in the reduction reactor, the second calcination conditions, etc.) to prepare the corresponding unit cell distorted pseudo-boehmite and oil hydrogenation catalyst. To save space, they will not be repeated here.

[0046]

[0047] The pseudo-boehmite in Examples 1 to 4 is a unit cell distorted pseudo-boehmite (P-1 to P-4) prepared according to the specific conditions specified in Table 2 below. The pseudo-boehmite in Comparative Examples 1 and 3 is a comparative sample (P-5, P-7) prepared according to the specific conditions specified in Table 2 below. The preparation method of the unit cell distorted pseudo-boehmite specifically includes the following steps:

[0048] S1. Placing aluminum nitrate in a crucible and performing a second calcination to obtain an amorphous aluminum oxide compound (i.e., amorphous aluminum oxide); wherein the second calcination temperature is 450-600° C. and the second calcination time is 4-8 hours;

[0049] S2. The prepared amorphous aluminum oxide compound is crushed and placed in an autoclave, wherein the particle size of the crushed amorphous aluminum oxide compound is less than 20 μm, and a urea solution having a urea concentration of 11.5 wt% to 18.5 wt% is added to the autoclave, and the mass ratio of the amorphous aluminum oxide compound to the urea solution is 1:2 to 1:10, and magnetic stirring is performed for 10 minutes to ensure uniform mixing; wherein the autoclave is lined with polytetrafluoroethylene;

[0050] S3. The autoclave is sealed, and then the mixed materials are subjected to low-temperature hydrothermal treatment and high-temperature hydrothermal treatment in sequence; wherein the temperature of the low-temperature hydrothermal treatment is 90-130° C., the time of the low-temperature hydrothermal treatment is 1-4 hours, and the temperature of the high-temperature hydrothermal treatment is 150-200° C., and the time of the high-temperature hydrothermal treatment is 4-8 hours; during the low-temperature hydrothermal treatment, the treatment temperature is low and the time is short, and the amorphous aluminum oxide compound first slowly forms unit cell distorted pseudo-boehmite nuclei in the system; during the high-temperature hydrothermal treatment, the unit cell distorted pseudo-boehmite nuclei continue to grow with amorphous aluminum oxide as raw material, facilitating the subsequent formation of the final unit cell distorted pseudo-boehmite; the morphology of the prepared unit cell distorted pseudo-boehmite is petal cluster-shaped and has abundant macropore channels;

[0051] S4. Filtering, washing, and performing a third drying on the material after the two hydrothermal treatments to obtain unit cell distorted pseudo-boehmite, wherein the third drying temperature is 100-160° C. and the third drying time is 6-10 hours. The obtained unit cell distorted pseudo-boehmite has a petal cluster morphology, wherein the petal cluster particles are composed of a plurality of lamellar particle clusters, the petal cluster particles have a size of 3-6 μm, the lamellar particles have a size of 0.3-0.8 μm, the lamellar length to width ratio is 3:1-6:1, and the lamellar thickness is 25-45 nm.

[0052] In a specific implementation, in step S2, the particle size of the amorphous aluminum oxide compound after the pulverization treatment is less than 10 μm.

[0053] In specific implementation, the pseudo-boehmite (P-6) purchased in Comparative Example 2 has a granular morphology rather than a petal-like cluster.

[0054]

[0055] In this application, scanning electron microscopy was used to characterize the microstructures of the unit cell distorted pseudo-boehmite (P-1 to P-4) prepared in Examples 1 to 4 and the comparative samples (P-5 to P-7) prepared in Comparative Examples 1 to 3, and corresponding scanning electron microscope images (SEM images) were obtained. For the purpose of simplicity, this application uses Example 1 as an example and provides an SEM image of the unit cell distorted pseudo-boehmite prepared in Example 1, as shown in FIG. Figure 1 shown.

[0056] Depend on Figure 1 It can be seen that the morphology of the unit cell distorted pseudo-boehmite provided in Example 1 of the present application is petal cluster-like, wherein the petal cluster-like particles are composed of lamellar particle clusters, the petal cluster-like particles have a size of 3-6 μm, the lamellar particle size is 0.3-0.8 μm, the length and width ratio of the lamellar is 3:1-6:1, and the lamellar thickness is 25-45 nm; the comparative sample prepared in Comparative Example 1 did not form petal clusters, further proving that other alkaline solutions except urea solution cannot prepare petal cluster-like pseudo-boehmite, other alkaline solutions such as ammonia solution and ammonium carbonate solution.

[0057] In this application, X-ray diffractometer was used to characterize the physical structure of the unit cell distorted pseudo-boehmite (P-1 to P-4) prepared in Examples 1 to 4 and the comparative samples (P-5 to P-7) prepared in Comparative Examples 1 to 3, and the corresponding XRD spectra were obtained. For the purpose of simplicity, this application uses Example 1 as an example to provide the XRD spectra of SB powder and the unit cell distorted pseudo-boehmite prepared in Example 1, as shown in FIG. Figure 2 As shown. Figure 2 It can be seen that the diffraction peak corresponding to the (020) crystal plane of the unit cell distorted pseudo-boehmite prepared in Example 1 of the present application is shifted compared with the SB powder, which further indicates that the prepared pseudo-boehmite is unit cell distorted pseudo-boehmite.

[0058] This application also calculated the percentage reduction δ of the (020) interplanar spacing of Examples 1 to 4 compared to the SB powder using the XRD spectra of the unit cell-distorted pseudo-boehmite (P-1 to P-4) and the XRD spectra of the SB powder prepared in Examples 1 to 4. The calculation showed that the percentage reduction of the (020) interplanar spacing of the unit cell-distorted pseudo-boehmite compared to the (020) interplanar spacing of the SB powder was 0.6%-1.9%.

[0059] To further demonstrate the beneficial effects of the unit cell-distorted pseudo-boehmite prepared in this application, this application also provides Examples 5 to 8, Comparative Examples 4 to 6, and a blank control, wherein the blank control is SB powder, which is further described. The addition ratios of the various raw materials and the preparation conditions in Examples 5 to 8 and Comparative Examples 4 to 6 are shown in Table 3 below.

[0060] In this application, scanning electron microscopy is used to characterize the microstructures of the products obtained in Examples 5 to 8, Comparative Examples 4 to 6, and a blank control, and corresponding scanning electron microscope images (SEM images) can be obtained. For the purpose of simplicity, this application takes Example 5 as an example and provides SEM images of the amorphous aluminum oxide compound and the unit cell distorted pseudo-boehmite prepared in Example 5, which are respectively Figure 3 and Figure 4Provides SEM images of pseudo-boehmite prepared in Comparative Example 4 to Comparative Example 6, respectively Figure 5 、 Figure 6 、 Figure 7 .

[0061] Depend on Figure 3 and Figure 4 It can be seen that the amorphous aluminum oxide compound provided in Example 5 of the present application does not produce petal cluster morphology, while the prepared unit cell distorted pseudo-boehmite is in the shape of petal clusters, composed of multiple layer clusters, with a novel and regular structure and uniform morphology; and contains abundant open macropore channels. Figures 5 to 7 As can be seen, the products prepared in Comparative Examples 4 to 6 do not have a petal-like cluster morphology. Therefore, other aluminum salts except aluminum nitrate and other alkaline solutions except urea solution cannot produce petal-like clusters of unit cell-distorted pseudo-boehmite. Other aluminum salts such as aluminum chloride and aluminum sulfate, and other alkaline solutions such as ammonia solution and ammonium carbonate solution cannot produce petal-like clusters of unit cell-distorted pseudo-boehmite.

[0062] In this application, the phase structures of the products obtained in Examples 5 to 8, Comparative Examples 4 to 6, and a blank control were characterized by an X-ray diffractometer to obtain corresponding XRD spectra. For the purpose of simplicity, this application takes Example 5 as an example and provides the XRD spectra of the amorphous aluminum oxide compound prepared in Example 5 (see FIG. Figure 8 As shown), the XRD spectra of SB powder and the unit cell distorted pseudo-boehmite prepared in Example 5 are provided (as shown Figure 9 shown).

[0063] Depend on Figure 9 It can be seen that the unit cell distorted pseudo-boehmite prepared in Example 5 of the present application has a diffraction peak corresponding to the (020) crystal plane shifted compared to the SB powder, which further proves that the unit cell distorted pseudo-boehmite prepared in the present application has unit cell distortion.

[0064] The present application also calculates the percentage reduction δ of the (020) crystal plane spacing of Examples 5 to 8 compared to the SB powder through the XRD spectra of the unit cell distorted pseudo-boehmite (P1~P4) and the XRD spectra of the SB powder prepared in Examples 5 to 8. The calculation results are shown in Table 3 below.

[0065]

[0066] As shown in Table 3, the unit cell-distorted pseudo-boehmite prepared in the present invention has a smaller (020) interplanar spacing than SB powder, with a reduction percentage of 0.6% to 1.9%. The unit cell-distorted pseudo-boehmite has a petal-like cluster shape with a size of 3 to 6 μm and a large specific surface area. The petal-like cluster is composed of multiple lamellae, with a lamella size of 0.3 to 0.8 μm, a lamella length-to-width ratio of 3:1 to 6:1, and a lamella thickness of 25 to 45 nm. Furthermore, conventional alkaline solutions such as ammonia water, ammonium carbonate, and sodium carbonate were also investigated, but none of them could achieve the same effect as the urea solution.

[0067] In summary, the distorted pseudo-boehmite prepared in this application exhibits a petal-like cluster structure, a novel and regular structure, and a uniform morphology, containing abundant macropores. Using distorted pseudo-boehmite as a raw material to prepare a catalyst can result in a high content of surface defects, thereby enhancing the catalyst's activity.

[0068] In order to further demonstrate the activity of the oil hydrogenation catalyst prepared using unit cell distorted pseudo-boehmite as raw material, the catalytic performance of the oil hydrogenation catalysts prepared in Examples 1 to 4 and the comparative catalysts prepared in Comparative Examples 1 to 3 were evaluated. The evaluation method is as follows:

[0069] 1200 g of soybean oil (iodine value 132.6 g / 100 g) and 0.75 g of catalyst were added to a 2 L autoclave. The stirring and heating devices were turned on. When the reaction temperature reached 185°C, nitrogen was introduced into the autoclave to replace the air in the autoclave. Hydrogen was then introduced into the autoclave to carry out a catalytic hydrogenation reaction. During the catalytic hydrogenation process, the pressure in the autoclave was maintained at 2 MPa. After 1.5 h of reaction, the temperature was lowered, the hydrogen was discharged, and the soybean oil in the autoclave was filtered to remove the catalyst. The iodine value of the soybean oil after the reaction was evaluated. The results are shown in Table 4.

[0070]

[0071] The lower the iodine value, the higher the hydrogenation activity of the catalyst. As can be seen from Table 4, the activity of the oil hydrogenation catalyst prepared by the method of the present application is higher than that of the comparison catalyst, which further proves that the oil hydrogenation catalyst prepared by the method of the present application has a higher hydrogenation activity.

[0072] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0073] Although the preferred embodiments of the present application have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present application.

[0074] Obviously, those skilled in the art may make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalents, this application is intended to include these modifications and variations.

Claims

1. A method for preparing a fat hydrogenation catalyst, characterized in that: The following steps are involved: (1) Preparation of unit cell distorted pseudo-boehmite; (2) impregnating the unit cell distorted pseudo-boehmite prepared in step (1) with a nickel-containing solution I to obtain an impregnated material I, adding an alkaline solution I to the impregnated material I for a first precipitation treatment, wherein the mass ratio of the impregnated material I to the alkaline solution I is 5:1-10:1, filtering, washing, and first drying the precipitated material, and then impregnating with a nickel-containing solution II to obtain an impregnated material II, adding an alkaline solution II to the impregnated material II for a second precipitation treatment, wherein the mass ratio of the impregnated material II to the alkaline solution II is 5:1-10:1, filtering, washing, second drying, and first calcining the precipitated material to obtain nickel-containing alumina; (3) Reducing the nickel-containing alumina obtained in step (2) to obtain a fat hydrogenation catalyst.

2. The method for preparing a fat hydrogenation catalyst according to claim 1, wherein In the step (1), the unit cell distorted pseudo-boehmite is prepared, which specifically includes the following steps: Aluminum nitrate is subjected to a second calcination to obtain an amorphous aluminum oxide compound. The obtained amorphous aluminum oxide compound is crushed and placed in an autoclave, and a urea solution is added to the autoclave. The mass ratio of the amorphous aluminum oxide compound to the urea solution is 1:2 to 1:

10. The mixture is evenly mixed, and then the mixed material is subjected to a low-temperature hydrothermal treatment and a high-temperature hydrothermal treatment in sequence. The material after the two hydrothermal treatments is filtered, washed, and dried for a third time to obtain unit cell distorted pseudo-boehmite.

3. The method for preparing a fat hydrogenation catalyst according to claim 2, wherein: In the preparation method of the unit cell distorted pseudo-boehmite, the second calcination temperature is 450-600°C, the second calcination time is 4-8 hours, the particle size of the amorphous aluminum oxide compound after pulverization is less than 20 μm, the concentration of urea in the urea solution is 11.5wt%-18.5wt%, the temperature of the low-temperature hydrothermal treatment is 90-130°C, the time of the low-temperature hydrothermal treatment is 1-4 hours, the temperature of the high-temperature hydrothermal treatment is 150-200°C, the time of the high-temperature hydrothermal treatment is 10-16 hours, the third drying temperature is 100-160°C, and the third drying time is 6-10 hours.

4. The method for preparing a fat hydrogenation catalyst according to claim 2, wherein: In the step (1), the unit cell distorted pseudo-boehmite has a petal cluster morphology, the petal cluster particles are composed of a plurality of lamellar particle clusters, the petal cluster particles have a size of 3-6 μm, the lamellar particles have a size of 0.3-0.8 μm, the length to width ratio of the lamellar is 3:1-6:1, and the lamellar thickness is 25-45 nm; The (020) crystal plane spacing of the unit cell distorted pseudo-boehmite is reduced by 0.6%-1.9% compared with the (020) crystal plane spacing of SB powder.

5. The method for preparing a fat hydrogenation catalyst according to claim 1, wherein: In the step (3), the nickel-containing aluminum oxide obtained in the step (2) is reduced to obtain a fat hydrogenation catalyst, which specifically includes: The nickel-containing alumina obtained in step (2) is placed in a reduction reactor, and a mixed gas of nitrogen and hydrogen is introduced into the reduction reactor to reduce the nickel-containing alumina to obtain a fat hydrogenation catalyst; wherein the reduction temperature is 450-550°C, the reduction time is 4-8 hours, and the volume ratio of nitrogen to hydrogen in the mixed gas is 4:1-2:

1.

6. The method for preparing a fat hydrogenation catalyst according to claim 1, characterized in that: In the step (2), the first precipitation time or the second precipitation time is 4-8 hours, the first drying temperature is 100-160°C, the first drying time is 4-10 hours, the second drying temperature is 100-160°C, the second drying time is 4-10 hours, the first roasting temperature is 450-550°C, and the first roasting time is 6-10 hours.

7. The method for preparing a fat hydrogenation catalyst according to claim 1, characterized in that: In the step (2), the nickel-containing solution I or the nickel-containing solution II is one or more of nickel acetate, nickel nitrate, nickel sulfate, nickel phosphate, and nickel carbonate; and the nickel content in the nickel-containing solution I or the nickel-containing solution II is 5.5 wt%-15.5 wt%.

8. The method for preparing a fat hydrogenation catalyst according to claim 1, wherein: In the step (2), the alkaline solution I or the alkaline solution II is one or more of sodium carbonate, sodium bicarbonate, and sodium hydroxide.

9. The method for preparing a fat hydrogenation catalyst according to claim 8, characterized in that: The pH value of the alkaline solution I or the alkaline solution II is 8-9.

5.

10. A fat hydrogenation catalyst, characterized in that: The catalyst is prepared according to the method for preparing the oil hydrogenation catalyst according to any one of claims 1 to 9.

Images