A carbon eight hydrogenation catalyst

Abstract

This invention discloses a C8 hydrogenation catalyst, which uses alumina with a leaf-like aggregate structure as a support. Based on 100% of the total catalyst weight, it contains 10-25 wt% nickel oxide, 0.01-4 wt% copper oxide, 0-3 wt% cerium oxide and / or lanthanum oxide, 0-5 wt% alkali metal and / or alkaline earth metal oxides, with the balance being the support. The catalyst has a specific surface area of ​​50-180 m². 2 Alumina with a pore volume of 0.30–0.60 ml / g and a lamellar aggregate structure was prepared via hydrothermal synthesis. The catalyst prepared using lamellar alumina as a support, with Ni as the main active component and Cu as the secondary active component, exhibits not only high selectivity but also good stability.

Description

Technical Field

[0001] This invention relates to a C8 hydrogenation catalyst, specifically a nickel-copper catalyst for the selective hydrogenation of phenylacetylene in a C8 fraction. Background Technology

[0002] Styrene is an important monomer for the production of polystyrene, ABS resin, styrene-butadiene rubber, etc. Ethylbenzene dehydrogenation is the main preparation method, but it suffers from high production costs. In recent years, with the large-scale production of ethylene, extracting styrene from the C8 fraction, a byproduct of ethylene cracking, has become a promising new route to increase styrene production.

[0003] Cracked gasoline is a byproduct of the ethylene industry, accounting for approximately 50% to 80% of ethylene production capacity. Styrene can be recovered by extracting its C8 fraction. A 1000 kt / a ethylene unit can produce approximately 20 to 40 kt / a of styrene, while also recovering mixed xylene. This upgrades the C8 fraction from fuel value to chemical value, and its production cost is about half that of traditional ethylbenzene dehydrogenation to styrene, giving it strong market competitiveness. Furthermore, the separation of the C8 fraction reduces the load on subsequent hydrogenation units of cracked gasoline, reduces hydrogen consumption, and avoids poisoning of the hydrogenation catalyst caused by styrene polymerization.

[0004] The current method for recovering styrene from cracked gasoline is extractive distillation, but the C8 fraction contains 4000–15000 μg·g⁻¹. -1 Phenylacetylene (PA) is present in styrene- ...

[0005] Patent ZL201110045258.X discloses a selective hydrogenation catalyst for phenylacetylene in the presence of styrene. The catalyst comprises, by weight percentage, the following components: (a) 2–50.0% metallic nickel or its oxide; (b) 0.05–10% of at least one element selected from rare earth elements or its oxide; (c) 0.01–6% of at least one element selected from IB, IIB, VIB, or VIIB of the periodic table or its oxide; and (d) 49–85% of a support. The support is selected from a composite support of alumina and silica, with a weight ratio of alumina to silica of 0.01–100:1. This technical solution can be used in the industrial production of phenylacetylene removal by hydrogenation in the presence of styrene. However, the drawback of this technology is that the addition of silica inevitably affects the acidity of the support, thereby affecting the operational stability of the catalyst.

[0006] Patent CN102649065A relates to a catalyst for the selective hydrogenation of phenylacetylene in the presence of styrene. The catalyst comprises, by weight percentage, the following components: (a) 2-50 parts of metallic nickel or its oxide; (b) 0.05-10 parts of at least one element selected from rare earth elements or its oxide; (c) 0.01-5 parts of at least one element selected from elements IA and IIA of the periodic table or its oxide; and (d) 49-85 parts of a support. The support is selected from alumina, and has an average pore size of 3-30 nm, a pore volume of 0.4-1.5 mL / g, and a specific surface area of ​​100-450 m² / g. This technology can be used in the industrial production of phenylacetylene removal by hydrogenation in the presence of styrene.

[0007] Patent CN 107952446A discloses a nickel catalyst for the selective hydrogenation of phenylacetylene in a C8 fraction, comprising, by weight percentage: (a) 5-30% metallic nickel or its oxide; (b) 0.01-20% of at least one element selected from molybdenum or tungsten or its oxide; (c) 0.01-10.0% of at least one element selected from rare earth elements or its oxide; (d) 0.01-2.0% of at least one element selected from IA or IIA of the periodic table or its oxide; (e) 0-15% of at least one element selected from silicon, phosphorus, boron or fluorine or its oxide; (f) 0-10% of at least one element selected from IVB of the periodic table or its oxide; and (g) the balance being alumina.

[0008] Patent CN 102649066 A relates to a selective hydrogenation catalyst for phenylacetylene in the presence of styrene, comprising, by weight percentage: 2-50.0% metallic nickel or its oxide; 0.05-10% of at least one element selected from rare earth elements or its oxide; and 40-88% of a support selected from at least one of alumina, silica, or molecular sieves, wherein the support has a specific surface area of ​​60-300 m². 2 / g.

[0009] Alumina, as an excellent catalyst support and adsorbent material, has wide applications in industry. The microstructure and surface properties of alumina significantly influence the performance of supported catalysts; therefore, the controllable synthesis of alumina morphology and size has attracted considerable research interest. Currently, researchers have prepared alumina morphologies including flakes, rods, and spheres using various methods. Nanoscale flake alumina possesses a large specific surface area and high surface energy, exhibiting high dispersibility for active metals in catalysts and a high diffusion rate for reactants, significantly reducing diffusion resistance. Therefore, as a support, it can greatly improve catalyst activity and anti-coking properties, demonstrating superior performance compared to traditional alumina. Currently, flake alumina research mainly focuses on the synthesis of micron-sized flake alumina, primarily for preparing flake alumina ceramics. The synthesis routes for nanoscale flake alumina are mostly developed based on surfactants as templates, resulting in higher costs and a tendency to agglomerate during high-temperature calcination, thus limiting its industrialization.

[0010] Patent CN201710944136.1 discloses a method for preparing a nano-alumina carrier with a surface rich in defect sites: the steps are as follows: (1) Inorganic aluminum salt and precipitant are dissolved in a water-ethylene glycol mixed solvent at a molar ratio of 1:5 to 1:9, and stirred to obtain a transparent solution. The solution is then transferred to a hydrothermal reactor. The hydrothermal reaction temperature is 100 to 200°C, and the reaction time is 12 to 48 hours. (2) After the reaction is completed, the reaction material is filtered, washed, dried, and calcined to obtain a nano-alumina carrier rich in surface defects, with a specific surface area of ​​150 to 400 m² / g and a pore volume of 0.34 to 0.62 cm³. 3 / g. However, ethylene glycol in the mixed solvent is easily oxidized by hydrothermal metabolism to produce toxic oxalic acid, thus it cannot be widely used as a solvent and is not conducive to promotion.

[0011] Patent CN201210427889.2 discloses a method for preparing an alumina support, comprising the following steps: measuring an appropriate amount of aluminum salt solution with a concentration of 0.5-2.5 mol / L, adding an appropriate amount of urea to the aluminum salt solution and stirring until completely dissolved, wherein the amount of urea added is equal to the ratio of urea to Al. 3+The molar ratio is 2-10:1; the above solution is placed in a sealed reaction vessel and reacted at 140℃-200℃ for 2-12 hours, and then the prepared alumina support is directly calcined. Although the support prepared by this method has a high specific surface area and large pore size, the defect of this technology or the deficiency of this invention is that, since the material obtained after the reaction is not filtered or washed, but directly dried and calcined to obtain the alumina support, the resulting alumina support has a high content of amorphous alumina and a dispersed pore distribution, which limits its further application.

[0012] Patent CN201110351132.5 discloses an improved hydrothermal method for preparing porous alumina ultrafine powder. The method uses aluminum inorganic salt as raw material and urea as co-precipitant to generate a precursor under hydrothermal conditions. The precursor is then centrifuged, washed, dried, and calcined to obtain porous alumina ultrafine powder with high purity, narrow particle size distribution, and high porosity.

[0013] Patent CN107540007A discloses a method for preparing nanosheet mesoporous alumina: using inorganic aluminum salt as the aluminum source, triethanolamine as the additive, and ethylenediamine as the precipitant, nanosheet mesoporous alumina is obtained by hydrothermal aging treatment. The thickness of the nanosheet alumina sheets is 1-10 nm and the width is 0.1-0.5 μm.

[0014] Patent CN107777713A discloses a γ-alumina hexagonal nanosheet material and its preparation method, with a size of 50-500 nm and a thickness of 5-10 nm. This invention uses aluminum alkoxides as raw materials, controls the two-dimensional growth of its intermediate alumina hydroxide through organic amines, and prepares γ-alumina hexagonal nanosheets using chemical precipitation and hydrothermal methods.

[0015] Patent CN104961146A discloses a nanosheet aluminum hydroxide colloid and its preparation method, which involves directly hydrothermally heating anhydrous ethanol and anhydrous aluminum chloride at 220-300℃ to obtain a nanosheet gel with a thickness of 3-20 nm.

[0016] Patent CN106276992A discloses a method for preparing leaf-shaped nano-γ-alumina. Inorganic aluminum salts and urea are dissolved in water to obtain a transparent solution. The solution is then transferred to a high-pressure reactor, and hydrogen gas is introduced into the reactor to maintain a certain pressure and temperature for the reaction to obtain leaf-shaped nano-γ-alumina. The drawbacks of this technology, or its shortcomings compared to the present invention, are that the leaves are in a dispersed state without aggregation. Agglomeration is likely to occur during high-temperature calcination. When used as a catalyst support for loading active metals, it reduces the dispersion of the active metals on the support surface. Furthermore, the use of relatively dangerous hydrogen gas during the preparation process is detrimental to production safety.

[0017] The article "Controllable Synthesis and Characterization of γ-Al2O3 Nanocrystals with Specific Morphology" discloses the preparation of 60-100 nm nanosheet alumina using acetic acid and isopropanol as raw materials via hydrothermal treatment at 200 °C. The main exposed crystal plane is the (110) crystal plane. The article "Synthesis of AlOOH nanocrystals with different morphologies dueto the effect of sulfate ions and the corresponding formation mechanism study" by Yuguo Xia et al., Phys. Chem. Chem. Phys., 2013, 15, 18290, uses nano-AlOOH as raw material, adds sodium sulfate and sulfuric acid, and hydrothermally treats at 200 °C for 24 hours to obtain nanosheet alumina with a size of 60-100 nm. The alumina prepared by this method has a small specific surface area (<100 nm). 2 Moreover, the preparation process uses dilute acid, and the high-temperature hydrothermal process places high demands on the reactor material, which is not conducive to large-scale production.

[0018] Existing patents and literature report synthetic routes for regularly morphologically structured lamellar alumina, which are either based on surfactant template methods, use expensive aluminum alkoxides as raw materials, or involve harsh synthesis conditions. Furthermore, the prepared lamellar alumina morphology is always dispersed nanosheets. Dispersed nanosheets suffer from drawbacks such as difficulty in product separation and agglomeration during high-temperature calcination (above 900°C), making it difficult to maintain the nanosheet morphology. Therefore, they lose the advantage of lamellar morphology as catalyst supports. Thus, it is necessary to provide a low-cost, simple method for preparing lamellar alumina with an aggregated structure.

[0019] This invention provides a regularly morphological leaf-shaped aggregate alumina and its preparation method. The obtained alumina has a leaf-shaped aggregate structure, characterized by regular morphology, uniform particle size, good crystallinity, and good thermal stability. Its leaf-shaped aggregate structure overcomes the shortcomings of general nano-sheet alumina products, which are difficult to separate and prone to agglomeration at high temperatures. It can maintain the nano-sheet morphology. The nickel-copper catalyst prepared with it for the selective hydrogenation of phenylacetylene in C8 fractions is used for the selective hydrogenation of phenylacetylene in C8 fractions. It removes phenylacetylene while the loss rate of styrene is low, and it has good selective hydrogenation performance. Summary of the Invention

[0020] The purpose of this invention is to provide a C8 hydrogenation catalyst. The technical problem to be solved is the low hydrogenation rate of phenylacetylene and the high loss rate of styrene in the selective hydrogenation of phenylacetylene in the presence of styrene. This invention provides a new selective hydrogenation catalyst for phenylacetylene in the presence of styrene, using alumina with a leaf-like aggregate structure as a support and nickel and copper as active components. The catalyst has the advantages of high hydrogenation rate of phenylacetylene and low loss rate of styrene.

[0021] To achieve the above objectives, the present invention provides a C8 hydrogenation catalyst, using alumina with a leaf-like aggregate structure as a support, and containing, by weight 100%, 10-25 wt% nickel oxide, 0.01-4 wt% copper oxide, 0-3 wt% cerium oxide and / or lanthanum oxide, 0-5 wt% alkali metal and / or alkaline earth metal oxides, with the balance being the support; the catalyst has a specific surface area of ​​50-180 m². 2 / g, pore volume 0.30~0.60ml / g. Leaf-like aggregated alumina was prepared by hydrothermal treatment.

[0022] The C8 hydrogenation catalyst of this invention uses alumina with a leaf-like aggregate structure as a support. Based on 100% of the total catalyst weight, it contains 13-18 wt% nickel oxide, 0.1-2.5 wt% copper oxide, 0.1-1.5 wt% cerium oxide and / or lanthanum oxide, 0.3-3 wt% alkali metal and / or alkaline earth metal oxides, with the balance being the support. The preferred specific surface area is 80-130 m². 2 / g, with a preferred pore volume of 0.35~0.50ml / g.

[0023] The catalyst of this invention may contain rare earth elements cerium and / or lanthanum (in oxide form) at a content of 0–3 wt%, preferably 0.1–1.5 wt%. The addition of cerium and / or lanthanum can suppress the growth of catalyst support grains during high-temperature calcination, improve the dispersion of the active component nickel, and thus enhance the hydrogenation selectivity and stability of the catalyst. In this invention, cerium and / or lanthanum are preferably added in the form of soluble nitrates.

[0024] The catalyst of this invention may further contain alkali metals and / or alkaline earth metals (in oxide form), with a content of 0-5 wt%, preferably 0.3-3 wt%. The alkali metals and / or alkaline earth metals are one or more of Li, Na, K, Ca, Mg, Sr, and Be, preferably one or two of Li, K, and Mg. When the catalyst is used for the selective hydrogenation of phenylacetylene, alkynes and dienes easily polymerize to form colloids and become deactivated. By adding alkali metals and / or alkaline earth metals, the acidity or alkalinity of the catalyst support surface can be adjusted. Adjusting the acidity or alkalinity of the catalyst surface can improve hydrogenation activity and stability, and is beneficial in reducing the deposition of carbonaceous and colloidal substances during hydrogenation. In this invention, the alkali metals and / or alkaline earth metals are preferably added in the form of soluble nitrates, acetates, or citrates.

[0025] The C8 hydrogenation catalyst of the present invention obtains nickel oxide and copper oxide by introducing soluble nickel salt and soluble copper salt into a support. The soluble nickel salt is one or more of nickel nitrate, nickel acetate, nickel chloride and nickel sulfate, preferably nickel nitrate and nickel acetate; the soluble copper salt is copper nitrate and / or basic copper carbonate.

[0026] The method for preparing the leaf-shaped aggregate structure alumina in the C8 hydrogenation catalyst of this invention is as follows:

[0027] Step (1): Dissolve the inorganic aluminum salt and the compound that can decompose into NH3 and CO2 in water to form a mixed solution;

[0028] Step (2): CO2 gas at a pressure of 0.1-2 MPa is introduced into the mixed solution, and then hydrothermal treatment is carried out at 120-200℃. The obtained hydrothermal product is subjected to solid-liquid separation. The obtained solid is washed, dried, kneaded and shaped, then dried and calcined to obtain alumina with a leaf-like aggregate structure.

[0029] The molar ratio of aluminum ions in inorganic aluminum salts to compounds that can decompose into NH3 and CO2 during hydrothermal treatment is 0.1 to 4.0.

[0030] In the C8 hydrogenation catalyst of the present invention, the pressure of CO2 introduced in step (2) is 0.2-1 MPa.

[0031] The C8 hydrogenation catalyst of the present invention contains one or more of the following compounds that can be decomposed into NH3 and CO2 in step (1): ammonium carbonate, ammonium bicarbonate, urea and ammonium oxalate.

[0032] The C8 hydrogenation catalyst of the present invention has a molar ratio of aluminum ions of the inorganic aluminum salt to compounds that can decompose into NH3 and CO2 in hydrothermal treatment of 0.5 to 3.

[0033] The C8 hydrogenation catalyst of the present invention, wherein the inorganic aluminum salt in step (1) is one or more of aluminum sulfate, aluminum nitrate and aluminum chloride.

[0034] The C8 hydrogenation catalyst of the present invention has a hydrothermal time of 2 to 48 hours in step (2); a calcination temperature of 620 to 1050°C and a calcination time of 3 to 10 hours.

[0035] The C8 hydrogenation catalyst of the present invention has a hydrothermal temperature of 120-200°C and a hydrothermal time of 4-24h in step (2), and a calcination temperature of 700-1000°C and a calcination time of 4-6h.

[0036] In the preparation process of the leaf-shaped aggregate structure alumina of the present invention, during the kneading process, a binder, extrusion aid, etc., can be added as needed. The specific substances used and the amounts added can be determined according to existing knowledge in the art. For example, the binder can be one or more of nitric acid, phosphoric acid, hydrochloric acid, and sulfuric acid, and the amount added is 3-10 wt% of the total weight of the sample to be formed; the extrusion aid can be guar gum powder, etc., and its amount is generally 2-6 wt% of the total weight of the sample to be formed.

[0037] The calcination method and conditions described are commonly used methods and conditions for calcining catalyst supports. Vertical furnaces, converters, and mesh belt kilns can be used for calcination. The calcination temperature of the support is the same as the calcination temperature of the support before impregnation with active components Ni and Cu, in order to ensure the specific surface area and pore volume required by the catalyst. Before calcination at this temperature, the support may be prepared by low-temperature calcination, but these are all intermediate transitional calcination steps.

[0038] The present invention also provides a more specific method for preparing a C8 hydrogenation catalyst, which involves impregnating a leaf-shaped aggregate structure alumina support with a solution containing nickel and copper through one or more steps, followed by drying and calcination to obtain the catalyst, but the preparation method is not limited to this.

[0039] In this invention, the active components nickel and copper are added in the form of soluble salts. The nickel source is selected from one or more of nickel nitrate, nickel acetate, nickel chloride, or nickel sulfate, with nickel nitrate and nickel acetate being preferred. Copper is preferably added in the form of copper nitrate or basic copper carbonate. This invention does not specify the preparation method of the catalyst in detail. For example, it can be prepared by an equal-volume impregnation method, in which an aqueous solution containing soluble salts of nickel and copper is impregnated onto a support, dried, and then calcined at 300–500°C for 3–8 hours.

[0040] Rare earth elements cerium and / or lanthanum, as well as alkali metals and / or alkaline earth metals, can be added during the carrier molding process; they can also be added to the carrier after molding and before impregnation of the active component; or they can be added simultaneously with the active component impregnation solution during the impregnation of the active component. It is best to add the carrier before impregnating the active component.

[0041] Specifically, rare earth elements cerium and / or lanthanum, as well as alkali metals and / or alkaline earth metals, are added during the carrier molding process, and the calcination temperature after carrier drying is 700–1000℃ and the calcination time is 4–6 h; or rare earth elements cerium and / or lanthanum, as well as alkali metals and / or alkaline earth metals, are added to the carrier after carrier molding and before impregnation of the active components, and the calcination temperature after carrier drying is 400–800℃ and the calcination time is 3–10 h, preferably 500–700℃ and 4–6 h.

[0042] To achieve the above objectives, the present invention also provides an application of a C8 hydrogenation catalyst, wherein the catalyst is reduced with hydrogen at 250–450°C for 6–24 hours before being used for C8 hydrogenation.

[0043] The C8 hydrogenation catalyst of this invention uses an inexpensive aluminum source as its leaf-like aggregate alumina support and does not require the addition of a template agent, thus offering advantages such as low cost and simple operation. By controlling the molar ratio of aluminum ions from the inorganic aluminum salt to compounds that can decompose into NH3 and CO2 during hydrothermal treatment, as well as the hydrothermal reaction temperature, leaf-like aggregate alumina with a regular morphology can be obtained. This leaf-like aggregate alumina exhibits regular morphology, uniform particle size, high crystallinity, and high thermal stability. Its leaf-like aggregate structure overcomes the disadvantages of conventional nanosheet alumina products, such as difficulty in separation and easy agglomeration at high temperatures. The leaf-like aggregate alumina of this invention is easy to separate and does not agglomerate during high-temperature calcination, maintaining its nanosheet morphology. Therefore, it can serve as an excellent catalyst support for catalytic hydrogenation reactions. In this invention, CO2 gas is introduced into the carrier during preparation, which effectively neutralizes the number of hydroxyl groups on the surface of alumina flakes during alumina crystallization. On the one hand, this reduces the flake curling caused by hydroxyl condensation during crystallization and effectively controls the width of the alumina flakes. On the other hand, it reduces the saturation of coordination between hydroxyl groups and aluminum ions, making the plate-like alumina more conducive to chelation coordination with active metals. Furthermore, this invention uses a high molar ratio of aluminum ions to compounds, which helps to increase the yield per batch and effectively reduce production costs.

[0044] The inventors unexpectedly discovered that the catalyst prepared using lamellar alumina as a support, with Ni as the main active component and Cu as the secondary active component, not only exhibits high selectivity but also good stability. Specifically, during the selective hydrogenation of the C8 fraction, while phenylacetylene is hydrogenated to styrene, styrene undergoes little or no hydrogenation. This is likely due to the high dispersion of Ni and Cu on the lamellar alumina support, allowing for the full utilization of their synergistic effect. Furthermore, when the support is treated with alkali metals or alkaline earth metals or mixtures thereof, this invention can effectively control the surface acidity of the support, which is beneficial for inhibiting further hydrogenation of styrene. Attached Figure Description

[0045] Figure 1 This is a SEM image of the leaf-shaped aggregate structure alumina prepared in Example 2 of the present invention.

[0046] Figure 2 This is a SEM image of the alumina prepared in Comparative Example 2 of this invention. Detailed Implementation

[0047] The present invention will now be described in detail through embodiments. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Those skilled in the art can make some non-essential improvements and adjustments to the present invention based on the above description.

[0048] Example 1

[0049] (1) Carrier preparation

[0050] Aluminum chloride and ammonium carbonate (molar ratio of aluminum ions to ammonium carbonate of 3.1) were added to deionized water, stirred until dissolved, and then transferred to a hydrothermal reactor. CO2 gas was introduced to 1.0 MPa, and the reaction was carried out at 140°C for 20 h. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, lithium carbonate, citric acid, and water to form a plastic body, which was then extruded into strips. The strips were then dried at 110°C for 6 h and calcined at 870°C for 4 h to obtain lithium-containing leaf-shaped alumina carriers.

[0051] (2) Catalyst preparation

[0052] Basic copper carbonate was dissolved in acetic acid, and then nickel acetate was added to dissolve in deionized water to prepare an impregnation solution. The solution was then impregnated onto the support prepared in (1) using an equal volume impregnation method. The solution was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst C1.

[0053] Catalyst C1 has a specific surface area of ​​148 m². 2 / g, pore volume is 0.55ml / g.

[0054] Example 2

[0055] (1) Carrier preparation

[0056] Aluminum nitrate and urea (molar ratio of aluminum ions to urea of ​​1.8) were added to deionized water, stirred until dissolved, and then transferred to a hydrothermal reactor. CO2 gas was introduced to 0.8 MPa, and the reaction was carried out at 180°C for 12 h. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, citric acid, guar gum powder, and water to form a plastic body, extruded into strips, dried at 120°C for 4 h, and calcined at 590°C for 4 h to obtain a leaf-shaped aggregate alumina support precursor. A potassium nitrate aqueous solution was prepared and impregnated onto the support using an equal-volume impregnation method. The support was dried at 110°C for 5 h and calcined at 950°C for 4 h to obtain a potassium-containing leaf-shaped aggregate alumina support. The support was characterized by scanning electron microscopy. Figure 1 As shown, the carrier has a leaf-like aggregate structure.

[0057] (2) Catalyst preparation

[0058] Nickel nitrate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal volume impregnation method. The solution was dried at 110°C and calcined at 360°C for 4 hours to obtain catalyst C2.

[0059] Catalyst C2 has a specific surface area of ​​117 m². 2 / g, pore volume is 0.45ml / g.

[0060] Example 3

[0061] (1) Carrier preparation

[0062] Aluminum sulfate and ammonium bicarbonate (molar ratio of aluminum ions to ammonium bicarbonate of 1.0) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 0.5 MPa. The reaction was carried out at 170°C for 15 hours. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, lanthanum nitrate, guar gum powder, and water to form a plastic body. The mixture was then extruded into strips, dried at 120°C for 4 hours, and calcined at 980°C for 4 hours to obtain a lanthanum-containing leaf-like aggregate structure alumina support.

[0063] (2) Catalyst preparation

[0064] Nickel chloride and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal volume impregnation method. The solution was dried at 110°C and calcined at 380°C for 4 hours to obtain catalyst C3.

[0065] Catalyst C3 has a specific surface area of ​​105 m² 2 / g, pore volume is 0.41ml / g.

[0066] Example 4

[0067] (1) Carrier preparation

[0068] Aluminum sulfate, aluminum nitrate, and urea (molar ratio of aluminum ions to urea of ​​2.4) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 0.7 MPa. The reaction was carried out at 160°C for 20 h. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic mass. The mass was extruded into strips, dried at 110°C for 6 h, and calcined at 570°C for 4 h to obtain a leaf-shaped aggregate alumina support precursor. An aqueous solution of lithium carbonate and citric acid was prepared and impregnated onto the support using an equal-volume impregnation method. The mixture was dried at 120°C for 4 h and calcined at 910°C for 4 h to obtain a lithium-containing leaf-shaped aggregate alumina support.

[0069] (2) Catalyst preparation

[0070] Nickel nitrate, copper nitrate, and lanthanum nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 400°C for 3 hours to obtain catalyst C4.

[0071] Catalyst C4 has a specific surface area of ​​129 m². 2 / g, pore volume is 0.48ml / g.

[0072] Example 5

[0073] (1) Carrier preparation

[0074] Aluminum nitrate, urea, and ammonium oxalate (the molar ratio of aluminum ions and the sum of the molar numbers of urea and ammonium oxalate was 1.5) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 1.2 MPa. The reaction was carried out at 150°C for 24 hours. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic mass. This mass was extruded into strips, dried at 120°C for 4 hours, and calcined at 560°C for 4 hours to obtain a leaf-shaped aggregate alumina carrier precursor. A cerium nitrate aqueous solution was prepared and impregnated onto the carrier using an equal-volume impregnation method. The carrier was dried at 100°C for 8 hours and calcined at 1000°C for 4 hours to obtain a cerium-containing leaf-shaped aggregate alumina carrier.

[0075] (2) Catalyst preparation

[0076] Basic copper carbonate was dissolved in acetic acid, and then nickel acetate was added to dissolve in deionized water to prepare an impregnation solution. The solution was then impregnated onto the support prepared in (1) using an equal volume impregnation method. The solution was dried at 120°C and calcined at 420°C for 3 hours to obtain catalyst C5.

[0077] Catalyst C5 has a specific surface area of ​​89 m². 2 / g, pore volume is 0.38ml / g.

[0078] Example 6

[0079] (1) Carrier preparation

[0080] Aluminum nitrate, aluminum sulfate, and urea (molar ratio of aluminum ions to urea of ​​2.2) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 0.9 MPa. The reaction was carried out at 200°C for 10 hours. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, citric acid, guar gum powder, and water to form a plastic body. The mixture was then extruded into strips, dried at 120°C for 4 hours, and calcined at 930°C for 4 hours to obtain a leaf-shaped aggregate alumina carrier.

[0081] (2) Catalyst preparation

[0082] The catalyst was prepared by a two-step impregnation method. In the first step, nickel nitrate and potassium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The total nickel content of the impregnated catalyst was 40%. The solution was dried at 110°C and calcined at 380°C for 4 hours to obtain catalyst precursor Q1. In the second step, nickel nitrate, cerium nitrate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 110°C and calcined at 450°C for 4 hours to obtain catalyst C6.

[0083] Catalyst C6 has a specific surface area of ​​123 m². 2 / g, pore volume is 0.47ml / g.

[0084] Example 7

[0085] (1) Carrier preparation

[0086] Aluminum chloride, aluminum nitrate, urea, and ammonium carbonate (the molar ratio of the sum of the molar numbers of aluminum ions and urea to ammonium carbonate was 0.4) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 1.5 MPa. The reaction was carried out at 220°C for 8 hours. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, citric acid, guar gum powder, and water to form a plastic body. The mixture was then extruded into strips, dried at 110°C for 6 hours, and calcined at 890°C for 4 hours to obtain an alumina carrier with a leaf-like aggregate structure.

[0087] (2) Catalyst preparation

[0088] The catalyst was prepared by a two-step impregnation method. In the first step, nickel acetate and strontium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The total nickel content of the impregnated catalyst was 30%, and the solution was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst precursor Q2. In the second step, nickel nitrate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto Q2 using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 450°C for 4 hours to obtain catalyst C7.

[0089] Catalyst C7 has a specific surface area of ​​139 m². 2 / g, pore volume is 0.52ml / g.

[0090] Example 8

[0091] (1) Carrier preparation

[0092] Aluminum sulfate and urea (molar ratio of aluminum ions to urea of ​​0.3) were added to deionized water and stirred until dissolved. The mixture was then transferred to a hydrothermal reactor, and CO2 gas was introduced to a pressure of 0.3 MPa. The reaction was carried out at 110°C for 36 hours. After cooling to room temperature, the precipitate was filtered, washed, and dried. The obtained product was mixed with nitric acid, phosphoric acid, citric acid, guar gum powder, and water to form a plastic body. The mixture was then extruded into strips, dried at 100°C for 8 hours, and calcined at 920°C for 4 hours to obtain an alumina carrier with a leaf-like aggregate structure.

[0093] (2) Catalyst preparation

[0094] The catalyst was prepared by a two-step impregnation method. In the first step, nickel acetate was dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The total nickel content of the impregnated catalyst was 35%. The solution was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst precursor Q3. In the second step, nickel nitrate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The solution was dried at 120°C and calcined at 430°C for 4 hours to obtain catalyst C8.

[0095] The C8 catalyst has a specific surface area of ​​131 m². 2 / g, pore volume is 0.47ml / g.

[0096] Comparative Example 1

[0097] (1) Carrier preparation

[0098] Boehmite (specific surface area 315 m²) prepared using commercially available carbonization method 2 / g, pore volume 0.96ml / g), mixed with nitric acid, phosphoric acid, guar gum powder, lithium carbonate, citric acid and water to form a plastic body, extruded into strips, and then dried at 110℃ for 6h and calcined at 870℃ for 4h to obtain a lithium-containing alumina carrier.

[0099] (2) Catalyst preparation

[0100] Basic copper carbonate was dissolved in acetic acid, and then nickel acetate was added to dissolve in deionized water to prepare an impregnation solution. The solution was then impregnated onto the support prepared in (1) using an equal volume impregnation method. The solution was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst D1.

[0101] Comparative Example 2

[0102] (1) Carrier preparation

[0103] Boehmite (specific surface area 332 m²) prepared using commercially available sulfuric acid method 2 / g, pore volume 1.01ml / g), mixed with nitric acid, phosphoric acid, citric acid, guar gum powder and water to form a plastic body, extruded into strips, and then dried at 120℃ for 4h and calcined at 590℃ for 4h to obtain the carrier precursor. A potassium nitrate aqueous solution was prepared and impregnated onto the carrier using an equal-volume impregnation method. The carrier was dried at 110℃ for 5h and calcined at 950℃ for 4h to obtain a potassium-containing alumina carrier. The carrier was characterized using scanning electron microscopy, such as... Figure 2 As shown, the carrier has an irregular shape.

[0104] (2) Catalyst preparation

[0105] Nickel nitrate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal volume impregnation method. The solution was dried at 110°C and calcined at 360°C for 4 hours to obtain catalyst D2.

[0106] Comparative Example 3

[0107] (1) Carrier preparation

[0108] Chinese patent CN106276992B discloses a method for preparing leaf-shaped nano-γ-alumina: 7.5g of aluminum nitrate and 6g of urea are added to 70mL of deionized water and magnetically stirred for 20 minutes to obtain a colorless and transparent solution. The solution is then transferred to a high-pressure reactor, and hydrogen gas is introduced to purge the air from the reactor. The hydrogen pressure in the reactor is then set to 0.5MPa, and the reactor is sealed. The reactor is heated to 160℃ and reacted for 12 hours. After the reaction, the reactor is allowed to cool naturally to room temperature, the gas inside the reactor is released, the reactor is opened, and the reaction slurry is collected. The slurry is filtered and dried to obtain boehmite monohydrate, which is mixed with nitric acid, phosphoric acid, guar gum powder, and water to form a plastic body. This body is then extruded into strips, dried at 120℃ for 4 hours, and calcined at 560℃ for 4 hours to obtain a carrier precursor. A cerium nitrate aqueous solution was prepared and impregnated onto a carrier using an equal-volume impregnation method. The carrier was then dried at 100°C for 8 hours and calcined at 1000°C for 4 hours to obtain a cerium-containing alumina carrier.

[0109] (2) Catalyst preparation

[0110] Basic copper carbonate was dissolved in acetic acid, and then nickel acetate was added to dissolve in deionized water to prepare an impregnation solution. The solution was then impregnated onto the support prepared in (1) using an equal volume impregnation method. The solution was dried at 120°C and calcined at 420°C for 3 hours to obtain catalyst D3.

[0111] Comparative Example 4

[0112] (1) Carrier preparation

[0113] Boehmite (specific surface area 325 m²) prepared using commercially available carbonization method 2 / g (pore volume 0.99ml / g), mixed with nitric acid, phosphoric acid, citric acid, guar gum powder and water to form a plastic body, extruded into strips, and then dried at 110℃ for 6h and calcined at 890℃ for 4h to obtain an alumina carrier.

[0114] (2) Catalyst preparation

[0115] The catalyst was prepared by a two-step impregnation method. In the first step, nickel acetate and strontium nitrate were dissolved in deionized water to prepare an impregnation solution, which was then impregnated onto the support prepared in (1) using an equal-volume impregnation method. The impregnation solution contained 30% of the total nickel content of the catalyst. The catalyst was dried at 120°C and calcined at 350°C for 4 hours to obtain catalyst precursor Q3. In the second step, nickel nitrate and copper nitrate were dissolved in deionized water to prepare an impregnation solution, which contained 70% of the total nickel content of the catalyst. The impregnation solution was then impregnated onto Q3 using an equal-volume impregnation method. The catalyst was dried at 120°C and calcined at 430°C for 4 hours to obtain catalyst D4.

[0116] Table 1. Composition of catalysts in the examples and comparative catalysts.

[0117]

[0118]

[0119] Characterization of active metal dispersion in catalysts:

[0120] Metal dispersion was determined using a CO pulse titration method on a Micromeritics Autochem 2920 chemisorption analyzer. 0.15 g of catalyst sample was reduced at 800 °C for 2 hours, then cooled to 40 °C and purged with helium for 60 min. CO pulse titration was performed using a loop injection method to titrate 5% CO-He, pulsed until the signal stabilized 5 times (minimum 20 pulses), and detected using a TCD detector. Specific results are shown in Table 2 below.

[0121] Table 2. Metal dispersion of catalysts in the examples and comparative catalysts.

[0122] catalyst Metal dispersion (Ni) C1 15.1％ C2 16.8％ C3 15.5％ C4 15.9％ C5 14.9％ C6 15.2％ C7 14.5％ C8 14.1％ D1 11.9％ D2 13.8％ D3 13.2％ D4 12.7％

[0123] As can be seen from the above examples and comparative examples, the C8 selective hydrogenation catalyst prepared by the present invention has a more excellent metal dispersion.

[0124] Catalytic performance of the catalyst:

[0125] Raw material sources and analytical methods:

[0126] The C8 cracking feedstock is sourced from Huifeng Petrochemical and contains 25–40 wt% styrene (ST) and 0.5–1.5 wt% phenylacetylene (PA).

[0127] Raw materials and product composition: The raw materials and composition were analyzed using an Agilent 7890B gas chromatograph.

[0128] Catalyst evaluation conditions: The catalyst was reduced at 420℃ for 8 hours under a hydrogen atmosphere in an adiabatic bed reactor. The reaction temperature was 30℃, the reaction pressure was 0.3 MPa, the H2 / PA volume ratio was 10, and the liquid hourly space velocity was 2 h⁻¹. -1 The catalyst loading volume is 150ml.

[0129] Reaction process flow: C8 fraction is metered through a metering tube and then pumped to the reaction pressure by a plunger pump. After preheating, it is mixed with hydrogen gas at a constant pressure and enters the catalyst bed from the bottom of the reactor. The reaction products are cooled and then enter a gas-liquid separator for separation. The separated H2 is depressurized and metered by a wet flow meter before being vented. The liquid is discharged into the product storage tank. The contents of ST, PA and other components are analyzed by Agilent 7890B gas chromatography.

[0130] The catalyst of this invention has a high PA hydrogenation rate and a low ST loss rate.

[0131] The specific evaluation conditions and results of the catalysts in the examples and comparative examples are shown in Table 3.

[0132] Table 3 Evaluation conditions and results for the examples and comparative examples

[0133]

[0134] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.

Claims

1. A carbon eight hydrogenation catalyst characterized in that, Alumina with a leaf-like aggregate structure as a carrier, containing 10-25 wt% of nickel oxide, 0.01-4 wt% of copper oxide, 0-3 wt% of cerium oxide and / or lanthanum oxide, 0-5 wt% of alkali and / or alkaline earth metal oxides, the rest being the carrier, based on the total weight of the catalyst; the specific surface area of the catalyst is 50-180 m 2 / g, the pore volume is 0.30-0.60 ml / g, the alumina with a leaf-like aggregate structure is prepared by a hydrothermal synthesis method. The method for preparing the leaf-shaped aggregate structure aluminum oxide is as follows: Step (1): dissolving inorganic aluminum salt and a compound capable of decomposing into NH3 and CO2 in hydrothermal treatment in water to form a mixed solution; Step (2): introducing CO2 gas with a pressure of 0.1-2 MPa into the mixed solution, then performing hydrothermal treatment at 100-300 ℃, and then performing solid-liquid separation on the obtained hydrothermal product, and then kneading the obtained solid after washing and drying into a shape, and then drying and calcining to obtain the leaf-shaped aggregate structure aluminum oxide; The molar ratio of aluminum ions in the inorganic aluminum salt to the compound capable of decomposing into NH3 and CO2 in hydrothermal treatment is 0.1-4.

0.

2. The carbon eight hydroprocessing catalyst of claim 1, wherein, Alumina with a leaf-like aggregate structure as a carrier, comprising 13-18 wt% of nickel oxide, 0.1-2.5 wt% of copper oxide, 0.1-1.5 wt% of cerium oxide and / or lanthanum oxide, 0.3-3 wt% of alkali and / or alkaline earth metal oxides, the rest being the carrier, the specific surface area of the catalyst being 80-130 m 2 / g, the pore volume being 0.35-0.50 ml / g.

3. The carbon eight hydrogenation catalyst according to claim 1 or 2, characterized in that, The alkali metal and / or alkaline earth metal is one or more of Li, Na, K, Ca, Mg, Sr and Be.

4. The octa-catalyst according to claim 1 or 2, wherein, The alkali metal and / or alkaline earth metal is one or two of Li, K and Mg.

5. The octa-catalyst according to claim 1 or 2, wherein, Oxides of nickel and copper are obtained by introducing soluble nickel salt and soluble copper salt into the carrier, the soluble nickel salt being one or more of nickel nitrate, nickel acetate, nickel chloride and nickel sulfate, and the soluble copper salt being copper nitrate and / or basic copper carbonate.

6. The C8 hydrogenation catalyst of claim 5, wherein, The soluble nickel salt is nickel nitrate and nickel acetate.

7. The C8 hydrogenation catalyst of claim 1, wherein, The pressure of the introduced CO2 in step (2) is 0.2-1 MPa.

8. The octa-catalyst of claim 1, wherein, The compound capable of decomposing into NH3 and CO2 in step (1) is one or more of ammonium carbonate, ammonium bicarbonate, urea and ammonium oxalate.

9. The octa-catalyst of claim 1, wherein, The molar ratio of aluminum ions in the inorganic aluminum salt to the compound capable of decomposing into NH3 and CO2 in hydrothermal treatment is 0.5-3.

10. The octa-catalyst of claim 1, wherein, The inorganic aluminum salt in step (1) is one or more of aluminum sulfate, aluminum nitrate and aluminum chloride.

11. The octa-catalyst of claim 1, wherein, The hydrothermal time in step (2) is 2-48 h, and the calcination temperature is 620-1050 ℃, and the calcination time is 3-10 h.

12. The carbon eight hydroprocessing catalyst of claim 1, wherein, The hydrothermal time in step (2) is 4-24 h, and the calcination temperature is 700-1000 ℃, and the calcination time is 4-6 h.

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