Ternary composite oxide carrier, carbon tetrayne selective hydrogenation non-noble metal catalyst, and preparation method and application thereof

Abstract

The application discloses a ternary composite oxide carrier, a carbon four alkyne selective hydrogenation non-noble metal catalyst and a preparation method and application thereof. The ternary composite oxide carrier is a ternary composite oxide carrier containing Al2O3, CuO and TiO2, wherein the CuO is distributed in the internal framework structure of Al2O3-TiO2; the content of the CuO accounts for 0.1-5% of the total weight of the carrier. The carbon four alkyne selective hydrogenation non-noble metal catalyst prepared based on the composite oxide carrier has the advantages of high low-temperature activity, high selectivity and high stability, compared with a noble metal selective hydrogenation alkyne removal catalyst, the catalyst can greatly save the production cost, and the catalyst has good anti-poisoning ability to impurities and raw material adaptability.

Description

Technical Field

[0001] This invention relates to a ternary composite oxide support and its preparation method, as well as a non-precious metal catalyst for selective hydrogenation of C4-acetylenes, its preparation method, and its application. Background Technology

[0002] 1,3-Butadiene, a raw material for synthetic rubber, is mainly obtained from the C4 fraction, a byproduct of ethylene cracking. Synthetic rubber requires that the total alkyne content in the 1,3-butadiene raw material be less than 20 ppm, with vinylacetylene less than 5 ppm. Therefore, it is essential to remove as many alkynes as possible while separating 1,3-butadiene from the C4 fraction.

[0003] There are many methods for removing alkynes and separating 1,3-butadiene, including solvent extraction, solvent absorption, chemical adsorption, catalytic polymerization, and catalytic selective hydrogenation. The traditional process is solvent extraction, which involves primary extraction, secondary extraction, light distillation, and heavy distillation to obtain 99% pure 1,3-butadiene. Secondary extraction primarily removes vinylacetylene (VA). The C4 alkynes removed by this method need to be diluted with other C4 hydrocarbons and then flared for combustion, resulting in significant resource waste. Furthermore, as the cracking depth increases, the alkyne concentration in the C4 alkynes increases, leading to a higher alkyne load on the extraction unit. This results in increased butadiene loss, higher energy consumption and compressor load, increased operational difficulty, and increased risk. Catalytic selective hydrogenation for alkyne removal not only replaces the secondary extraction in solvent extraction units, reducing investment and saving energy, but also solves the mismatch problem of the aforementioned equipment. Moreover, it can increase the production of large quantities of high-value butadiene when processing C4 alkynes with high alkyne content, making its economic advantages increasingly recognized. Currently, alkynes in mixed C4 fractions can be removed by catalytic selective hydrogenation. The catalysts used primarily tend to be noble metal catalysts, such as palladium, platinum, and silver, followed by non-noble metal catalysts, such as copper and nickel.

[0004] The advantage of non-precious metal copper catalysts lies in their high selectivity for alkyne hydrogenation. However, their disadvantages include lower activity and poor heat resistance; copper particles tend to grow rapidly at high temperatures (200℃), posing a safety risk should overheating occur during use. Copper-based selective hydrogenation catalysts also present certain safety hazards when treating tail gases with high alkyne concentrations (10–30 wt%), and are therefore generally used for selective hydrogenation of tail gases with lower alkyne concentrations.

[0005] The selective hydrogenation of alkynes in hydrocarbon streams requires different catalysts and reaction conditions depending on the composition of the feedstock and the desired product. A good selective hydrogenation catalyst, besides possessing high hydrogenation activity, should also exhibit good stability, meaning it should be resistant to impurities and gum deposits to extend its lifespan. Therefore, the support should have low acidity, a small specific surface area, and a large pore size. Furthermore, adding certain promoters during catalyst preparation can also extend the catalyst's lifespan.

[0006] Noble metal catalysts generally employ palladium catalysts supported on a carrier (usually alumina), with the addition of other co-catalyst components such as gold, silver, chromium, copper, iron, rhodium, lithium, potassium, and even lead or zinc. Noble metal catalysts exhibit good low-temperature activity and mild reaction conditions, but their drawbacks include easy loss of active components, high cost, difficulty in regeneration, and slightly poor hydrogenation selectivity. Non-noble metal catalysts require higher temperatures and harsher hydrogenation conditions, but their preparation is simple, they are easy to regenerate repeatedly, and their cost is relatively low, thus still possessing certain research and development value. In these hydrogenation reactions, semi-hydrogenated free radicals adsorbed on the catalyst react with adjacent alkynes or dienes to form a viscous polymer (commonly known as green oil), mainly composed of compounds with more than six carbon atoms. Because it covers the catalyst surface, it blocks the micropores, reducing catalyst activity and affecting catalyst lifespan. Especially for conjugated dienes (such as 1,3-butadiene), their polymerization reaction is more likely to occur, causing the catalyst to deactivate quickly, thus requiring frequent regeneration for reuse.

[0007] Therefore, using non-precious metal hydrogenation catalysts for the hydrogenation of alkynes can improve the catalyst's resistance to impurity poisoning and its stability, resulting in better economic value. Summary of the Invention

[0008] To address the aforementioned problems in the existing technology, this invention provides a novel ternary composite oxide support and its preparation method. The non-precious metal catalyst for selective hydrogenation of C4 acetylene based on this ternary composite oxide support has the advantages of high low-temperature activity, high selectivity, and high stability. Compared with precious metal selective hydrogenation catalysts for acetylene removal, the catalyst investment cost can be reduced by more than 80%, and the catalyst has good resistance to impurity poisoning and adaptability to raw materials.

[0009] The first aspect of this invention provides a ternary composite oxide support comprising Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure; the CuO content accounts for 0.1-5% by weight of the total weight of the support. In this invention, the chemical structural formula of the ternary composite oxide support can be Al2O3-CuO-TiO2, and the CuO is distributed within the Al2O3-TiO2 framework structure, forming Al-O-Cu-O-Ti bonds. Because Cu is uniformly distributed within the framework of the composite oxide, it is very stable, thus the prepared composite oxide support has the advantage of high-temperature resistance. Simultaneously, Cu can also improve the hydrogenation selectivity of the catalyst. The absence of characteristic diffraction peaks for Cu oxide in the XRD pattern indicates that CuO is located within the framework structure.

[0010] According to some embodiments of the composite oxide support of the present invention, the CuO content accounts for 0.1 to 5% of the total weight of the support, for example, but not limited to 0.3 to 5% by weight, 0.3 to 4% by weight, 0.3 to 3% by weight, 0.6 to 5% by weight, 0.6 to 4% by weight, 0.6 to 3% by weight, 1 to 5% by weight, 1 to 4% by weight, 1 to 3% by weight, 2 to 5% by weight, 2 to 4% by weight, 2 to 3% by weight, etc.

[0011] According to some embodiments of the composite oxide support of the present invention, the TiO2 content accounts for 5 to 20% of the total weight of the support.

[0012] According to some embodiments of the composite oxide carrier of the present invention, the Al2O3 content accounts for 75 to 94.9% of the total weight of the carrier.

[0013] A second aspect of the present invention provides a method for preparing a composite oxide support, comprising:

[0014] Step 1: Add soluble copper salt solution, titanium salt solution and mixed alkali solution to the soluble aluminum salt solution in parallel flow, maintain pH = 5.5-7.0, hold for 15-20 min, stop adding soluble copper salt and titanium salt solution, continue adding mixed alkali to make pH = 8-10, hold for 15-20 min, and obtain precipitate;

[0015] Step 2: Wash the precipitate, dry it for the first time, and calcine it for the first time to obtain the composite oxide carrier.

[0016] According to some embodiments of the method described in this invention, the soluble aluminum salt is selected from one or more of aluminum sulfate, aluminum chloride, and aluminum nitrate. In this invention, the solvent for the soluble aluminum salt solution can be water, ethanol, etc.

[0017] According to some embodiments of the method described in this invention, the soluble copper salt is selected from one or more of copper nitrate, copper sulfate, copper chloride, cuprous iodide, and organic soluble copper salts (e.g., but not limited to copper acetate). In this invention, the solvent for the soluble copper salt solution can be water, ethanol, etc.

[0018] In some embodiments of the method according to the present invention, the titanium salt is selected from one or more of metatitanic acid, titanium sulfate, titanium chloride, tetraethyl titanate, and tetrabutyl titanate. In the present invention, when metatitanic acid is used, sulfuric acid is preferably used as a solvent for dissolution.

[0019] According to some embodiments of the method described in this invention, the mixed alkali solution is formed by mixing an ammonium salt solution and an alkali solution.

[0020] According to some embodiments of the method described in this invention, the ammonium salt is selected from one or more of ammonium bicarbonate, ammonium carbonate, ammonium chloride, ammonium nitrate, ammonium sulfate, and ammonium bisulfate. In this invention, the solvent for the ammonium salt solution can be water, ethanol, etc.

[0021] According to some embodiments of the method described in this invention, the alkaline solution is selected from one or more of ammonia water, sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium methoxide, potassium ethoxide, and potassium tert-butoxide. In this invention, the solvent for the alkaline solution can be water, etc.

[0022] According to some embodiments of the method of the present invention, the concentration of ammonium salt in the ammonium salt solution is 0.1 to 0.3 mol / L.

[0023] According to some embodiments of the method described in this invention, the concentration of alkali in the alkaline solution is 0.2 to 0.4 mol / L.

[0024] According to some embodiments of the method described in this invention, the concentration of aluminum salt in the soluble aluminum salt solution is 0.5–2.5 mol / L.

[0025] According to some embodiments of the method described in this invention, the concentration of copper salt in the soluble copper salt solution is 0.1 to 1 mol / L.

[0026] According to some embodiments of the method described in this invention, the concentration of titanium salt in the titanium salt solution is 0.2 to 1.2 mol / L.

[0027] According to some embodiments of the method described in this invention, the pH value of the mixed alkaline solution is 11 to 12.

[0028] According to some embodiments of the method described in this invention, the temperature of the parallel flow is 50–90°C.

[0029] According to some embodiments of the method described in this invention, the conditions for the first drying include: a temperature of 100–120°C and a time of 4–12 hours.

[0030] According to some embodiments of the method described in this invention, the conditions for the first calcination include: a temperature of 700–1100°C and a time of 4–8 hours.

[0031] A third aspect of this invention provides a ternary composite oxide support prepared according to the above-described preparation method. This ternary composite oxide support comprises Al₂O₃, CuO, and TiO₂, wherein CuO is distributed within the Al₂O₃-TiO₂ framework structure; the CuO content accounts for 0.1–5% by weight of the total weight of the support. In this invention, the chemical structural formula of the ternary composite oxide support can be Al₂O₃-CuO-TiO₂, where CuO is distributed within the Al₂O₃-TiO₂ framework structure, forming Al-O-Cu-O-Ti bonds. Because Cu is uniformly distributed within the framework of the composite oxide, it is very stable, thus the prepared composite oxide support has the advantage of high-temperature resistance. Simultaneously, Cu can also improve the hydrogenation selectivity of the catalyst. No characteristic diffraction peaks of Cu oxide are found in the XRD pattern, indicating that CuO is located within the framework structure.

[0032] According to some embodiments of the composite oxide support of the present invention, the CuO content accounts for 0.1 to 5% of the total weight of the support. For example, but not limited to: 0.3 to 5% by weight, 0.3 to 4% by weight, 0.3 to 3% by weight, 0.6 to 5% by weight, 0.6 to 4% by weight, 0.6 to 3% by weight, 1 to 5% by weight, 1 to 4% by weight, 1 to 3% by weight, 2 to 5% by weight, 2 to 4% by weight, 2 to 3% by weight, etc.

[0033] According to some embodiments of the composite oxide support of the present invention, the TiO2 content accounts for 5 to 20% of the total weight of the support.

[0034] According to some embodiments of the composite oxide carrier of the present invention, the Al2O3 content accounts for 75 to 94.9% of the total weight of the carrier.

[0035] The fourth aspect of the present invention provides a method for preparing a non-precious metal catalyst for selective hydrogenation of C4 acetylene, comprising: impregnating the above-mentioned ternary composite oxide support with a soluble nickel salt solution, followed by a second drying and a second calcination.

[0036] In some embodiments of the method according to the present invention, the soluble nickel salt is selected from one or more of nickel nitrate, nickel acetate, nickel chloride, and nickel sulfate.

[0037] According to some embodiments of the method described in this invention, the concentration of nickel salt in the soluble nickel salt solution is 0.3–5 mol / L.

[0038] According to some embodiments of the method described in this invention, the conditions for the second drying include: a temperature of 100–120°C and a time of 4–24 hours.

[0039] According to some embodiments of the method described in this invention, the conditions for the second calcination include: a temperature of 500–800°C and a time of 4–8 hours.

[0040] The fifth aspect of this invention provides a non-precious metal catalyst for the selective hydrogenation of C4-tetrayne prepared according to the method described above. The Ni content in the catalyst is 8–25% by weight, based on Ni atoms.

[0041] The sixth aspect of the present invention provides a method for selective hydrogenation of C4 acetylenes, wherein a distillate oil is subjected to selective hydrogenation of acetylenes in the presence of the aforementioned non-precious metal catalyst for selective hydrogenation of C4 acetylenes, wherein the distillate oil is preferably a high-acetylene tail gas produced as a byproduct of a butadiene extraction unit.

[0042] According to some embodiments of the hydrogenation method of the present invention, in the selective hydrogenation of alkynes, the reaction temperature is 20-40°C, the molar ratio of hydrogen to alkynes is 1-2.5:1, the pressure is 0.5-0.8 MPa, and the recycle ratio is 10:1-30:1.

[0043] The beneficial effects of this invention are:

[0044] The ternary composite oxide support of this invention comprises Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure, forming Al-O-Cu-O-Ti bonds. A high copper content in the catalyst ensures the safety and stability of treating high-concentration alkyne hydrogenation tail gas. Furthermore, the inventors have surprisingly discovered that the composite oxide support prepared by the method provided by this invention exhibits high thermal stability at high temperatures due to the strong interaction between Al2O3, CuO, and TiO2, overcoming the instability of elemental copper at high temperatures. Moreover, even after high-temperature calcination of TiO2 at 700–1000°C, the anatase active phase is maintained, ensuring catalyst activity and overturning conventional understanding (anatase gradually transforms into rutile at high temperatures, and mesoporous anatase transforms into rutile at 550–600°C). Meanwhile, Al2O3 can maintain the crystal phase of γ-Al2O3, ensuring the crushing strength and pore structure of the catalyst, meeting the requirements of industrial applications. The selective hydrogenation catalyst prepared based on this composite oxide support has good activity, high selectivity, and good stability, and has industrial application value. Attached Figure Description

[0045] Figure 1 The image shows the XRD pattern of the composite oxide support A provided in Example 1 of this invention.

[0046] Figure 2 The XRD pattern of the non-precious metal catalyst A1 for selective hydrogenation of C4-acetylenes provided in Example 1 of this invention; Detailed Implementation

[0047] To make the present invention easier to understand, the present invention will be described in detail below with reference to embodiments. These embodiments are for illustrative purposes only and are not limited to the scope of application of the present invention.

[0048] The testing method and equipment used in this invention are as follows:

[0049] (1) Characterization of crystal phase structure: The crystal phase structure of the catalyst in the examples was characterized using an EMPYREAN X-ray diffractometer from Panaco GmbH, Netherlands. Cu Kα was used as the radiation source. The X-ray tube voltage was 40 kV, the tube current was 40 mA, the slit width was 10 mm, the scanning range was 5–90°, and the scanning speed was 0.013° / s.

[0050] (2) The methods for determining specific surface area and pore volume are as follows:

[0051] The specific surface area and pore structure of the catalyst were determined using an ASAP 2020 adsorption instrument (N2 adsorption method) manufactured by Micron Instruments, Inc., USA. Before testing, the catalyst sample was degassed at 623 K for 4 hours. Nitrogen gas was adsorbed at liquid nitrogen temperature using AMSM software, and the specific surface area of ​​the sample was obtained using the Brunauer-Emmet-Teller (BET) method. Simultaneously, the average pore size was obtained using the Barrett-Joyner-Halenda (BJH) method based on the nitrogen adsorption isotherm, and the pore volume was obtained using the P / Po single-point desorption curve.

[0052] 【Example 1】

[0053] Prepare 1 L of 0.78 mol / L aluminum sulfate deionized water (soluble aluminum salt solution), 0.5 L of 0.45 mol / L dilute sulfuric acid solution of metatitanic acid (titanium salt solution), 50 mL of 0.75 mol / L copper nitrate water (soluble copper salt solution), and mix 0.22 mol / L ammonium bicarbonate solution with 25% (w) ammonia water to obtain 1 L of mixed alkali solution with pH=11.

[0054] At 65°C, soluble copper salt, titanium salt, and mixed alkali solutions were added concurrently to a soluble aluminum salt solution, maintaining the pH at 6.2 for 20 minutes. The addition of soluble copper and titanium salt solutions was then stopped, and the mixed alkali solution was added again until the pH reached 9.1, which was then maintained for another 20 minutes. A precipitate was obtained.

[0055] The precipitate was washed five times with 20 times its volume of deionized water. The washed precipitate was then dried at 110℃ for 6 hours and calcined at 860℃ for 5 hours to obtain ternary composite oxide support A. This ternary composite oxide support is a ternary composite oxide support of Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure. The contents of CuO, TiO2, and Al2O3 as a percentage of the total weight of the support are shown in Table 1. XRD characterization was performed, and the XRD pattern of the ternary composite oxide support is shown below. Figure 1 As shown, no characteristic diffraction peaks of Cu oxide were found in the XRD pattern, indicating that CuO is located inside the framework structure. The ternary composite oxide support refers to Al2O3-CuO-TiO2, where CuO is distributed within the Al2O3-TiO2 framework structure, forming Al-O-Cu-O-Ti bonds.

[0056] A non-precious metal catalyst A1 for the selective hydrogenation of C4-tetrayne hydrocarbons was prepared by impregnating the composite oxide support with a 4 mol / L nickel nitrate impregnation solution at room temperature for 6 h, followed by drying at 110 °C for 12 h and calcination at 600 °C for 5 h. The crystal structure of the non-precious metal catalyst A1 for the selective hydrogenation of C4-tetrayne hydrocarbons was characterized, and its XRD pattern is shown below. Figure 2 .from Figure 2 It can be seen that TiO2 exists in the form of anatase, Al2O3 exists in the form of γ-Al2O3, and CuO is uniformly distributed within the catalyst's framework structure. The XRD pattern does not show characteristic diffraction peaks for CuO, indicating that CuO is located within the framework structure.

[0057] 【Example 2】

[0058] Prepare 1 L of 0.78 mol / L aluminum sulfate deionized water (soluble aluminum salt solution), 0.5 L of 0.35 mol / L dilute sulfuric acid solution of metatitanic acid (titanium salt solution), 50 mL of 0.53 mol / L copper nitrate solution (soluble copper salt solution), and mix 0.22 mol / L ammonium bicarbonate solution with 25% by weight ammonia water to prepare 1 L of mixed alkali solution with pH=12.

[0059] At 75°C, soluble copper salt, titanium salt, and mixed alkali solutions were added concurrently to an aluminum salt solution, maintaining the pH at 6.8 for 15 minutes. The addition of copper and titanium salt solutions was then stopped, and the mixed alkali solution was added again until the pH reached 8.5, which was then maintained for another 15 minutes. A precipitate was obtained.

[0060] The precipitate was washed repeatedly seven times with 30 times its volume of deionized water. The washed precipitate was then dried at 120°C for 6 hours and calcined at 950°C for 4 hours to obtain ternary composite oxide support B. This ternary composite oxide support is a ternary composite oxide support of Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure. The contents of CuO, TiO2, and Al2O3 as a percentage of the total weight of the support are shown in Table 1.

[0061] The composite oxide support was impregnated with a nickel nitrate impregnation solution with a concentration of 4.5 mol / L at room temperature for 6 h, then dried at 110 °C for 12 h and calcined at 500 °C for 5 h to obtain a non-precious metal catalyst B1 for selective hydrogenation of C4 acetylenes with a Ni content of 13.68 wt%.

[0062] 【Example 3】

[0063] The method is the same as in Example 1, except that: the titanium salt solution is replaced with 0.5 L of a dilute sulfuric acid solution of metatitanic acid with a concentration of 0.25 mol / L; and the soluble copper salt solution is replaced with 50 mL of a copper nitrate solution with a concentration of 0.17 mol / L.

[0064] A ternary composite oxide support C was obtained. This ternary composite oxide support is a ternary composite oxide support of Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure. The contents of CuO, TiO2, and Al2O3 as a percentage of the total weight of the support are shown in Table 1.

[0065] Finally, a non-precious metal catalyst C1 for the selective hydrogenation of C4-acetylenes was obtained.

[0066] 【Example 4】

[0067] The method is the same as in Example 1, except that the titanium salt solution is replaced with a dilute sulfuric acid solution of metatitanic acid with a concentration of 0.64 mol / L; and the soluble copper salt solution is replaced with 50 mL of copper nitrate solution with a concentration of 0.1 mol / L.

[0068] The ternary composite oxide support D was obtained. This ternary composite oxide support is a ternary composite oxide support of Al2O3, CuO and TiO2, wherein CuO is distributed inside the Al2O3-TiO2 framework structure. The contents of CuO, TiO2 and Al2O3 as a percentage of the total weight of the support are shown in Table 1.

[0069] The final product was a non-precious metal catalyst D1 for the selective hydrogenation of C4-acetylenes.

[0070] 【Example 5】

[0071] The method is the same as in Example 1, except that the soluble aluminum salt solution is replaced with aluminum nitrate at a concentration of 2.5 mol / L; and the titanium salt solution is replaced with an aqueous solution of titanium sulfate at a concentration of 1.2 mol / L.

[0072] A ternary composite oxide support E was obtained. This ternary composite oxide support is a ternary composite oxide support of Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure. The contents of CuO, TiO2, and Al2O3 as a percentage of the total weight of the support are shown in Table 1.

[0073] Finally, a non-precious metal catalyst E1 for the selective hydrogenation of C4-acetylenes was obtained.

[0074] 【Example 6】

[0075] Prepare 1 L of 0.78 mol / L aluminum sulfate deionized water (soluble aluminum salt solution), 0.5 L of 0.45 mol / L dilute sulfuric acid solution of metatitanic acid (titanium salt solution), 50 mL of 0.75 mol / L copper nitrate water (soluble copper salt solution), and mix 0.22 mol / L ammonium bicarbonate solution with 25% (w) ammonia water to obtain 1 L of mixed alkali solution with pH=11.

[0076] At 65°C, soluble copper salt, titanium salt, and mixed alkali solutions were added concurrently to a soluble aluminum salt solution, maintaining the pH at 5.5 for 20 minutes. The addition of soluble copper and titanium salt solutions was then stopped, and the mixed alkali solution was added again until the pH reached 10, which was then maintained for another 20 minutes. A precipitate was obtained.

[0077] The precipitate was washed five times with 20 times its volume of deionized water. The washed precipitate was then dried at 110℃ for 6 hours and calcined at 860℃ for 5 hours to obtain the ternary composite oxide support F. This ternary composite oxide support is a ternary composite oxide support of Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure. The contents of CuO, TiO2, and Al2O3 as a percentage of the total weight of the support are shown in Table 1.

[0078] The composite oxide support was impregnated with a nickel nitrate impregnation solution with a concentration of 4 mol / L at room temperature for 6 h, then dried at 110 °C for 12 h and calcined at 600 °C for 5 h to obtain the non-precious metal catalyst F1 for selective hydrogenation of C4 acetylenes.

[0079] 【Example 7】

[0080] Prepare 1 L of 0.78 mol / L aluminum sulfate deionized water (soluble aluminum salt solution), 0.5 L of 0.45 mol / L dilute sulfuric acid solution of metatitanic acid (titanium salt solution), 50 mL of 0.75 mol / L copper nitrate water (soluble copper salt solution), and mix 0.22 mol / L ammonium bicarbonate solution with 25% (w) ammonia water to obtain 1 L of mixed alkali solution with pH=11.

[0081] At 65°C, soluble copper salt, titanium salt, and mixed alkali solutions were added concurrently to a soluble aluminum salt solution, maintaining the pH at 7.0 for 20 minutes. The addition of soluble copper and titanium salt solutions was then stopped, and the mixed alkali solution was added again until the pH reached 8.0, which was then maintained for another 20 minutes. A precipitate was obtained.

[0082] The precipitate was washed five times with 20 times its volume of deionized water. The washed precipitate was then dried at 110℃ for 6 hours and calcined at 860℃ for 5 hours to obtain the ternary composite oxide support G. This ternary composite oxide support is a ternary composite oxide support of Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure. The contents of CuO, TiO2, and Al2O3 as a percentage of the total weight of the support are shown in Table 1.

[0083] The composite oxide support was impregnated with a nickel nitrate impregnation solution with a concentration of 4 mol / L at room temperature for 6 h, then dried at 110 °C for 12 h and calcined at 600 °C for 5 h to obtain the non-precious metal catalyst G1 for selective hydrogenation of C4 acetylenes.

[0084] Comparative Example 1

[0085] A 0.42 mol / L aluminum sulfate deionized water solution, a 0.19 mol / L metatitanic acid dilute sulfuric acid solution, and a 0.38 mol / L ammonium bicarbonate solution were prepared by mixing with 1.75 mol / L ammonia water to obtain a mixed alkaline solution with pH=11.

[0086] Under normal pressure and at a temperature of 70-75℃, the above-mentioned deionized aqueous solution of aluminum sulfate, dilute sulfuric acid solution of metatitanic acid, and mixed alkali solution were co-precipitated by parallel flow. The flow rate of the mixed alkali solution was controlled to maintain the pH of the precipitate within the range of 5.0-6.0 for 8 minutes. Then, the flow rate of the mixed alkali solution was increased to maintain the pH of the mixed solution within the range of 8.5-9.5 for 8 minutes. Then, the flow rate of the mixed alkali solution was decreased to maintain the pH of the mixed solution within the range of 5.0-6.0 for 8 minutes. The flow rate of the mixed alkali solution was then increased again to maintain the pH of the precipitate within the range of 8.5-9.5. This process was repeated until all the solution was added. The reaction solution was allowed to stand at 70℃ for 30 minutes, filtered, and the precipitate was obtained. The filter cake was washed with 15 times the volume of deionized water for 30 minutes, filtered again, and washed again. This process was repeated four times. Finally, the precipitate was dried at 110℃ for 11 hours and calcined at 950℃ for 5 hours to obtain the complex DB-1. The contents of CuO, TiO2, and Al2O3 in the composite as a percentage of the total weight of the carrier are shown in Table 1.

[0087] 156g of composite DB-1 was impregnated with 100mL of nickel nitrate aqueous solution (concentration: 15gNi / 100mL) for 1h. After filtration, the mixture was dried at 110℃ for 6h and calcined at 600℃ for 4h to obtain Ni / Al2O3-TiO2 catalyst DB1 with Ni content of 13.68%.

[0088] Table 1

[0089]

[0090]

[0091] [Test Example]

[0092] Catalysts from Examples 1-7 and Comparative Example 1 were used for selective hydrogenation of butadiene extraction tail gas.

[0093] The raw material used was butadiene extraction tail gas from a certain factory. The composition is shown in Table 2.

[0094] Table 2. Composition of butadiene extraction tail gas from a certain factory

[0095] composition weight% 1 Isobutane 2.658 2 n-Butane 5.652 3 trans-2-butene 5.994 4 n-Butene 24.635 5 Isobutylene 31.445 6 cis-2-butene 2.986 7 1,3-Butadiene 3.162 8 1,2-Butadiene 0 9 Vinylacetylene (VA) 20.563 10 Ethylacetylene (EA) 2.344

[0096] This test example uses a fixed-bed pilot-scale evaluation device from Tuochuan Scientific Equipment Co., Ltd., loaded with 50 mL of catalyst, to carry out a selective hydrogenation reaction of butadiene extraction tail gas.

[0097] Reaction conditions: reaction pressure 0.5-0.7 MPa, hydrogen flow rate 1.92 L / h, reactor inlet temperature 30℃, recycle ratio 20:1, feed rate 25 mL / h.

[0098] Catalysts A1, B1, C1, D1, E1, F1, G1, and DB1 were evaluated under the same conditions, and the results of hydrogenation and alkyne removal are shown in Table 3.

[0099]

[0100]

[0101]

[0102] The above description is merely a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, based on the technical teachings provided by the present invention and as common knowledge in the field, other equivalent modifications and improvements can be made, and these should also be considered within the scope of protection of the present invention.

Claims

1. A ternary composite oxide support for a non-precious metal catalyst for the selective hydrogenation of C4-acetylenes, characterized in that, The ternary composite oxide support is a ternary composite oxide support containing Al2O3, CuO, and TiO2, wherein CuO is distributed within the Al2O3-TiO2 framework structure; the CuO content accounts for 0.1~5% by weight of the total weight of the support, the TiO2 content accounts for 5~20% by weight of the total weight of the support, and the Al2O3 content accounts for 75~94.9% by weight of the total weight of the support. The preparation method of the ternary composite oxide support includes: Step 1: Add soluble copper salt solution, titanium salt solution and mixed alkali solution in parallel flow to a soluble aluminum salt solution, maintain pH = 6.2~7.0, hold for 15~20 min, stop adding soluble copper salt and titanium salt solutions, continue adding mixed alkali to make pH = 9.1~10, hold for 15~20 min, and obtain precipitate; the temperature of the parallel flow addition is 65~90℃; Step 2: Wash the precipitate, dry it for the first time, and calcine it for the first time to obtain the composite oxide carrier.

2. A method for preparing a ternary composite oxide support for a non-precious metal catalyst for selective hydrogenation of C4-tetrayne as described in claim 1, characterized in that, include: Step 1: Add soluble copper salt solution, titanium salt solution and mixed alkali solution in parallel flow to a soluble aluminum salt solution, maintain pH = 6.2~7.0, hold for 15~20 min, stop adding soluble copper salt and titanium salt solutions, continue adding mixed alkali to make pH = 9.1~10, hold for 15~20 min, and obtain precipitate; the temperature of the parallel flow addition is 65~90℃; Step 2: Wash the precipitate, dry it for the first time, and calcine it for the first time to obtain the composite oxide carrier.

3. The preparation method according to claim 2, characterized in that, The soluble aluminum salt is selected from one or more of aluminum sulfate, aluminum chloride, and aluminum nitrate; and / or, The soluble copper salt is selected from one or more of copper nitrate, copper sulfate, copper chloride, and copper acetate; and / or, The titanium salt is selected from one or more of metatitanic acid, titanium sulfate, titanium chloride, tetraethyl titanate, and tetrabutyl titanate; and / or, The mixed alkaline solution is formed by mixing an ammonium salt solution and an alkaline solution.

4. The preparation method according to claim 3, characterized in that, The ammonium salt is selected from one or more of ammonium bicarbonate, ammonium carbonate, ammonium chloride, ammonium nitrate, ammonium sulfate, and ammonium bisulfate; and / or, The alkaline solution is selected from one or more of ammonia water, sodium hydroxide aqueous solution, and potassium hydroxide aqueous solution.

5. The preparation method according to claim 4, characterized in that, The concentration of ammonium salt in the ammonium salt solution is 0.1~0.3 mol / L; and / or the concentration of alkali in the alkaline solution is 0.2~0.4 mol / L.

6. The preparation method according to any one of claims 2-5, characterized in that, The concentration of aluminum salt in the soluble aluminum salt solution is 0.5~2.5 mol / L; and / or, the concentration of copper salt in the soluble copper salt solution is 0.1~1 mol / L; and / or, the concentration of titanium salt in the titanium salt solution is 0.2~1.2 mol / L; and / or, the pH value of the mixed alkaline solution is 11~12.

7. The preparation method according to any one of claims 2-5, characterized in that, The first drying conditions include: a temperature of 100~120℃ and a time of 4~12h; and / or, the first calcination conditions include: a temperature of 700~1100℃ and a time of 4~8h.

8. A method for preparing a non-precious metal catalyst for the selective hydrogenation of C4-tetrayne, comprising: The ternary composite oxide carrier of claim 1 or the ternary composite oxide carrier prepared by any one of claims 2-7 is impregnated with a soluble nickel salt solution, followed by a second drying and a second calcination.

9. The preparation method according to claim 8, characterized in that, The soluble nickel salt is selected from one or more of nickel nitrate, nickel acetate, nickel chloride, and nickel sulfate; and / or, The second drying conditions include: a temperature of 100~120℃ and a time of 4~24h; and / or, the second calcination conditions include: a temperature of 500~800℃ and a time of 4~8h.

10. The non-precious metal catalyst for selective hydrogenation of C4-acetylenes prepared by the method according to claim 8 or 9, characterized in that, The Ni content in the catalyst is 8-25% by weight, based on Ni atoms.

11. A method for selective hydrogenation of C4 acetylenes, wherein a distillate oil is selectively hydrogenated in the presence of the non-precious metal catalyst for selective hydrogenation of C4 acetylenes as described in claim 10, wherein the distillate oil is a C4 distillate oil.

12. The method according to claim 11, characterized in that, The distillate oil is a high-alkyne tail gas produced as a byproduct of the butadiene extraction unit.

13. The method according to claim 11 or 12, characterized in that, In the selective hydrogenation process of the alkyne, the reaction temperature is 20~40℃, the molar ratio of hydrogen to alkyne is 1~2.5:1, the pressure is 0.5~0.8MPa, and the recycle ratio is 10:1~30:1.

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