Carbon four fraction selective hydrogenation catalyst and application thereof

Abstract

The application discloses a carbon four fraction selective hydrogenation catalyst and application thereof, the catalyst takes a leaf-like aggregate structure alumina as a carrier, and contains 10-25wt% of nickel oxide, 0.1-5wt% of zinc oxide, 0-2.5wt% of cerium oxide and / or lanthanum oxide, and the rest is the carrier, with the total mass of the catalyst being 100%. The catalyst has a specific surface area of 60-150m 2 / g, and a pore volume of 0.30-0.50cm 3 / g. When the leaf-like aggregate structure alumina is used as the carrier, the Ni-Zn active component can be well dispersed on the surface of the carrier, the active sites are fully exposed, the utilization rate of active atoms is improved, and then the hydrogenation performance of the catalyst is improved. The metal-carrier effect between the leaf-like aggregate structure alumina carrier and the Ni-Zn active component is beneficial to the catalyst to exhibit excellent activity and stability in the carbon four fraction selective hydrogenation reaction.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogenation catalysts, and particularly relates to a C4 fraction selective hydrogenation catalyst and application thereof. BACKGROUND

[0002] C4 fraction is an important primary processed hydrocarbon mixture product, and its comprehensive utilization technology includes C4 fraction olefin production, aromatization, alkylation, etc., and is one of the research and development hotspots in the current chemical industry. As for mixed C4 from various sources, in addition to main components such as n-butene, isobutene and butane, there is a certain concentration of butadiene (0.1-1 wt%), which can cause rapid deactivation of the subsequent butene utilization catalyst, and further affect the downstream process and product quality. Therefore, selective hydrogenation removal of butadiene in C4 fraction is the basis for its value-added utilization. The most widely used C4 fraction hydrogenation catalyst in current industrial application is a supported Pd catalyst, which has high production cost.

[0003] Chinese patent CN111054388A discloses a nickel-based C4 fraction selective hydrogenation catalyst and a preparation method thereof. The improved magnesium-aluminum spinel material is used as the main carrier, and pseudo-boehmite is added as an additive to prepare a Ni-Ag-based non-noble metal catalyst. The catalyst performance is improved by taking advantage of the improved quality of the spinel material, the catalyst cost is greatly reduced, and the 1-butene isomerization activity is low.

[0004] Chinese patent CN106582706A discloses a butadiene selective hydrogenation catalyst, which mainly solves the technical problems of high catalyst cost and high n-butene loss in the prior art. The catalyst carrier is alumina, the active component is nickel, and the additive is an IB group metal and an alkali metal. The catalyst contains 5-20 parts of nickel or its oxide, 0.5-4 parts of an IB group metal or its oxide, 0-2 parts of an alkali metal or its oxide, and 75-88 parts of the carrier alumina, in terms of catalyst weight fraction. The catalyst can be used for selective hydrogenation of materials containing butadiene, but is more suitable for treating C4 raw materials with a butadiene content of ≤0.6%.

[0005] Chinese patent CN106622245A discloses an alkyne and diene selective hydrogenation catalyst and a method for selectively hydrogenating and removing alkyne and diene from C4 fraction by using the catalyst. The alkyne and diene selective hydrogenation catalyst comprises a carrier and an active component loaded on the carrier. The carrier is carbon-coated alumina, and the active component comprises Cu element and Ni element. The content of the Cu element is 2-20 wt% based on the weight of the carrier, and the content of the Ni element is 2-20 wt%. The alkyne and diene selective hydrogenation catalyst has high activity, strong sulfur resistance and long service life when applied to the process of selectively hydrogenating and removing alkyne and diene from C4 fraction.

[0006] Chinese patent CN201410723841.5 discloses a non-noble metal selective hydrogenation catalyst, the active component is amorphous nickel phosphide, the promoter is one or more of lanthanum, cerium, praseodymium, samarium, ytterbium and other rare earth elements (preferably cerium), and the carrier is alumina; the non-noble metal catalyst has a catalytic activity comparable to that of a noble metal catalyst in the process of selective hydrogenation removal of butadiene from carbon four raw materials, can greatly reduce the cost of the catalyst, and has a relatively low 1-butene isomerization activity. When preparing the catalyst, the dry gel precursor is first heat-treated in a tube furnace with N2, and then the passivated catalyst is prepared through extrusion molding, H2 reduction, and O2 / N2 passivation treatment. The whole preparation process is complex, and the catalyst prepared by this method still needs to be reduced before hydrogenation.

[0007] Chinese patent CN201010172070.7 prepares a carbon four selective hydrogenation catalyst by reducing the main metal active component precursor and the auxiliary metal active component precursor supported on the carrier by ionizing radiation, the main metal active component is Pd in a single state, and the average diameter of the main metal active component particles and the auxiliary metal active component particles is less than 10 nm. The catalyst has high activity and selectivity, does not need to be reduced with hydrogen in advance, and can be used directly. However, the preparation of the catalyst has strict requirements on equipment, and there are certain problems in large-scale industrial production.

[0008] Chinese patent CN201910404239.8 discloses a method for removing butadiene from C4 components by adding a regulator, which adopts a two-stage selective hydrogenation process, the active component of the catalyst used is palladium, the selective promoter is cobalt, ruthenium and silver, and the supporting carrier is a mixture of alumina, ceria-zirconia and attapulgite. By controlling the concentration and adding amount of the regulator H2S, the surface active component of the catalyst is partially inactivated, which can meet the requirements of butadiene hydrogenation to generate 1-butene, remove butadiene to a depth of 0.97 ppm, avoid excessive side reactions, and the yield of 1-butene is 100.29%. However, the carrier composition of the catalyst is multiple, the components are difficult to mix uniformly, the two-stage selective hydrogenation process is complex, and in addition, H2S needs to be introduced as a regulator during pretreatment of the catalyst, and improper treatment can easily cause catalyst deactivation.

[0009] Chinese patent CN201410471757.9 discloses a supported catalyst for selective hydrogenation of carbon four fraction to 1-butene, which comprises an organic polymer material carrier and Raney alloy particles supported on the surface of the carrier. The Raney alloy comprises metallic copper and leachable elemental aluminum. The Raney alloy particles are supported on the surface of the carrier in the form of being partially embedded in the organic polymer material carrier by molding the carrier coated with the Raney alloy particles under the temperature conditions of carrier forming process or without curing and shaping. Each Raney alloy particle has a part embedded in the carrier. The catalyst effectively utilizes the surface area of the carrier, so that the active metal loading is very high, and the catalyst has good stability. However, the catalyst preparation process and equipment are strict, and it is difficult to popularize in large-scale production.

[0010] Alumina is widely used in industry as a good catalyst carrier and adsorbent material. The micro-morphology and surface properties of alumina have a great influence on the performance of supported catalysts, so the controllable synthesis of alumina morphology has attracted the interest of many researchers. At present, researchers have prepared alumina with different morphologies, mainly including flaky, rod-shaped and spherical shapes. Nanosheet alumina has a large specific surface area and high surface energy, and has a high dispersion of active metals for catalysts, as well as a large diffusion rate for reactants, which can significantly reduce diffusion resistance. Therefore, as a carrier, it can greatly improve the activity and anti-coking performance of the catalyst, and exhibit more excellent performance than traditional alumina. At present, flaky alumina mainly focuses on the synthesis of micron-sized flaky alumina, which is mainly used for the preparation of flaky alumina ceramics. The synthesis route of nanosheet alumina is mainly based on surfactants as templates, which has high cost and is prone to agglomeration during high-temperature calcination, which limits the realization of industrialization to a certain extent.

[0011] Chinese patent CN106276992A discloses a method for preparing leaf-shaped nanometer γ-alumina. Inorganic aluminum salt and urea are dissolved in water to obtain a transparent solution, which is then transferred to a high-pressure reaction kettle. Hydrogen gas is introduced into the high-pressure reaction kettle to maintain a certain pressure and temperature for reaction to obtain leaf-shaped nanometer γ-alumina. However, the leaves are in a dispersed state and do not accumulate, which is prone to agglomeration during high-temperature calcination. When used as a catalyst carrier to load active metals, it will reduce the dispersion of active metals on the surface of the carrier. Moreover, dangerous hydrogen gas is used in the preparation process, which is not conducive to production safety.

[0012] Chinese patent CN107777713A discloses a method for preparing γ-alumina hexagonal nanosheet material, which has a size of 50-500 nm and a thickness of 5-10 nm. The invention uses metal aluminum alkoxide as raw material, controls the two-dimensional growth of intermediate hydroxyl alumina by using organic amine, and adopts chemical precipitation and hydrothermal method to prepare γ-alumina hexagonal nanosheet.

[0013] Chinese patent CN201710944136.1 discloses a preparation method of a nano-alumina carrier with a surface rich in defect sites: the steps are as follows: (1) dissolve inorganic aluminum salt and precipitant in a water-ethylene glycol mixed solvent according to a molar ratio of 1:5-1:9, stir to obtain a transparent solution, and transfer the solution to a hydrothermal kettle; the hydrothermal reaction temperature is 100-200℃, and the reaction time is 12-48h; (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, which has a specific surface area of 150-400m 2 / g and a pore volume of 0.34-0.62cm 3 / g. However, ethylene glycol in the mixed solvent is prone to hydrothermal metabolism oxidation to generate toxic oxalic acid, so it cannot be widely used as a solvent and is not conducive to popularization.

[0014] Chinese patent CN201210427889.2 discloses a preparation method of an alumina carrier, which includes the following contents: measure an appropriate amount of aluminum salt solution with a concentration of 0.5-2.5mol / L, add an appropriate amount of urea to the aluminum salt solution and stir to completely dissolve the urea, the molar ratio of urea to Al 3+ ; after the above solution is placed in a sealed reaction container and reacted at 140℃-200℃ for 2-12h, the prepared alumina carrier is directly calcined. The carrier prepared by the method has a high specific surface area and a large pore size, but since the material obtained after the reaction is not filtered and washed, but directly dried and calcined to prepare the alumina carrier, the obtained alumina carrier has a high content of amorphous alumina and a dispersed pore distribution, which limits its further application.

[0015] Chinese patent CN201110351132.5 provides a method for preparing porous alumina superfine powder by an improved hydrothermal method, which uses aluminum inorganic salt as raw material and urea as co-precipitant to generate a precursor under hydrothermal conditions, and centrifugal separation, washing, drying, and calcination are performed to obtain porous alumina superfine powder, which has high purity, narrow particle size distribution, and high porosity.

[0016] Chinese patent CN107540007A discloses a preparation method of nano-sheet-shaped mesoporous alumina: using inorganic aluminum salt as aluminum source and triethanolamine as additive, and ethylenediamine as precipitant, nano-sheet-shaped mesoporous alumina is obtained by hydrothermal aging treatment, the nano-sheet-shaped alumina has a sheet layer thickness of 1-10nm and a width of 0.1-0.5um.

[0017] Chinese patent CN104961146A discloses a nano-sheet-shaped aluminum hydroxide colloid and a preparation method thereof, which directly hydrothermally obtains a nano-sheet-shaped gel at 220-300℃ by using anhydrous ethanol and anhydrous aluminum chloride, and the thickness of the nano-sheet-shaped gel is 3-20nm.

[0018] Li Jinlin et al. "Controllable synthesis and characterization of specific morphology gamma-Al2O3 nanocrystals, Journal of South-Central University for Nationalities (Natural Science Edition), 2016, 35: 1-4" prepared aluminum oxide nanosheets with a length of 60-100 nm by hydrothermal synthesis at 200℃ using acetic acid and isopropyl alcohol as raw materials, and the main outer exposed crystal face is (110) crystal face. Yuguo Xia et al. "Synthesis of AlOOH nanocrystals with different morphologies due to the effect of sulfate ions and the corresponding formation mechanism study, Phys. Chem. Chem. Phys., 2013, 15, 18290" prepared aluminum oxide nanosheets with a size of 60-100 nm by hydrothermal treatment at 200℃ for 24 hours using nano-AlOOH as raw material and adding sulfuric acid and sulfuric acid. The specific surface area of the aluminum oxide prepared by this method is small (<100 m 2 / g), and the use of dilute acid in the preparation process and the high-temperature hydrothermal process have high requirements for the kettle material, which is not conducive to large-scale production. SUMMARY

[0019] The purpose of the present application is to provide a carbon four fraction selective hydrogenation catalyst, which has excellent hydrogenation activity and stability, and can replace the noble metal Pd / Al2O3 catalyst to provide a reliable and feasible catalytic technology for carbon four alkylation raw material pre-hydrogenation.

[0020] The purpose of the present application is also to provide an application of a carbon four fraction selective hydrogenation catalyst.

[0021] To achieve the above purpose, the present application provides a carbon four fraction selective hydrogenation catalyst, which uses leaf-shaped aggregate structure aluminum oxide as a carrier, and contains 10-25wt% of nickel oxide, 0.1-5wt% of zinc oxide, 0-2.5wt% of cerium oxide and / or lanthanum oxide, and the balance is the carrier, based on 100% of the total mass of the catalyst, the specific surface area of the catalyst is 60-150 m 2 / g, and the pore volume is 0.30-0.50 cm 3 / g.

[0022] The carbon four fraction selective hydrogenation catalyst described in the present application uses leaf-shaped aggregate structure aluminum oxide as a carrier, and contains 15-20wt% of nickel oxide, 0.2-4.5wt% of zinc oxide, 0.1-1.5wt% of cerium oxide and / or lanthanum oxide, and the balance is the carrier, based on 100% of the total mass of the catalyst.

[0023] The carbon four fraction selective hydrogenation catalyst of the present application is prepared by introducing soluble nickel salt and soluble zinc salt into the carrier to obtain nickel oxide and zinc oxide, wherein the soluble nickel salt is one or more of nickel nitrate, nickel acetate, nickel chloride and nickel sulfate, preferably nickel nitrate; and the soluble zinc salt is one or more of zinc chloride, zinc sulfate, zinc nitrate and zinc acetate, preferably zinc nitrate.

[0024] The carbon four fraction selective hydrogenation catalyst of the present application is prepared by the following method for preparing the leaf-shaped aggregate structure alumina:

[0025] Step (1): dissolving inorganic aluminum salt and compound capable of decomposing into NH3 and CO2 in hydrothermal treatment into water to form a mixed solution;

[0026] Step (2): introducing CO2 gas with a pressure of 0.1-2 MPa into the mixed solution, then performing hydrothermal treatment at 120-200 ℃, 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 leaf-shaped aggregate structure alumina;

[0027] The molar ratio of aluminum ions of the inorganic aluminum salt to the compound capable of decomposing into NH3 and CO2 in hydrothermal treatment is 0.1-4. In the carbon four fraction selective hydrogenation catalyst of the present application, the pressure of the introduced CO2 in step (2) is 0.2-1 MPa.

[0028] In step (1) of the carbon four fraction selective hydrogenation catalyst of the present application, the compound capable of decomposing into NH3 and CO2 is one or more of ammonium carbonate, ammonium bicarbonate, urea and ammonium oxalate.

[0029] In the carbon four fraction selective hydrogenation catalyst of the present application, the molar ratio of aluminum ions of the inorganic aluminum salt to the compound capable of decomposing into NH3 and CO2 in hydrothermal treatment is 0.5-3.

[0030] In step (1) of the carbon four fraction selective hydrogenation catalyst of the present application, the inorganic aluminum salt is one or more of aluminum sulfate, aluminum nitrate and aluminum chloride.

[0031] In step (2) of the carbon four fraction selective hydrogenation catalyst of the present application, the hydrothermal time is 4-24 h; and the calcination temperature is 800-1000 ℃, and the calcination time is 4-6 h.

[0032] In the preparation process of the blade-like aggregate structure alumina, one or more of the colloidal solvents and extrusion aids can be added during kneading according to the requirements, and the specific substances and the added amounts can be determined according to the prior art. For example, the colloidal solvent can be one or more of nitric acid, phosphoric acid, hydrochloric acid and sulfuric acid, and the added amount is 3-10 wt% of the total weight of the sample to be formed; the extrusion aid can be sesbania powder, and the amount is generally 2-6 wt% of the total weight of the sample to be formed.

[0033] The calcination method and conditions are the commonly used method and conditions for catalyst carrier calcination, and vertical furnace, rotary furnace and mesh belt kiln can be used for calcination. The preferred calcination conditions of the carrier are 800-1000℃ calcination for 4-10h. The calcination temperature of the carrier is the calcination temperature of the carrier before impregnation of the active components Ni and Zn, so as to ensure the specific surface area and pore volume required by the catalyst, and to obtain the carrier with specific nickel and aluminum mixed crystal form. Before calcination at this temperature, the carrier can be prepared by low-temperature calcination, but it is an intermediate transition calcination step.

[0034] In the present application, the active components nickel and zinc are added in the form of soluble salt. The nickel source is selected from one or more of nickel nitrate, nickel acetate, nickel chloride or nickel sulfate, and preferably nickel nitrate. The zinc source is selected from zinc chloride, zinc sulfate, zinc nitrate and zinc acetate, and preferably is added in the form of zinc nitrate. The preparation method of the catalyst is not limited in detail, for example, an equal-volume impregnation method can be used to prepare the catalyst. A water solution containing soluble salts of nickel and zinc is impregnated on the carrier, and then dried and calcined at 300-500℃ for 3-8h.

[0035] The catalyst described in the present application can also contain rare earth elements cerium and / or lanthanum (in the form of oxide). After the addition of cerium and / or lanthanum, the grain growth of the catalyst carrier during high-temperature calcination can be inhibited, the dispersion of the active components nickel and zinc can be improved, and the hydrogenation selectivity and stability of the catalyst can be improved. In the present application, cerium and / or lanthanum are preferably added in the form of soluble nitrate.

[0036] The present application also provides a more specific preparation method of a carbon four fraction selective hydrogenation catalyst, but the preparation method is not limited thereto. A solution containing nickel and zinc is used to impregnate the alumina carrier by one or more steps, and then the catalyst is obtained by drying and calcination. Rare earth elements cerium and / or lanthanum can be added during the shaping of the carrier; can also be added to the carrier before impregnation of the active components after the shaping of the carrier; or can be added at the same time as the impregnation solution of the active components.

[0037] In order to achieve the above-mentioned purpose, the present application also provides an application of a carbon four fraction selective hydrogenation catalyst. The catalyst is reduced by hydrogen at 380-450℃ for 6-16h, and then used for carbon four fraction selective hydrogenation.

[0038] The present application has the following beneficial effects:

[0039] The Ni-based carbon four fraction selective hydrogenation catalyst of the present application has an alumina carrier with a leaf-shaped aggregate structure, which uses an inexpensive aluminum source as raw material and does not add a template agent, and has the advantages of low cost and simple operation. By controlling the molar ratio of aluminum ions of inorganic aluminum salt and compounds capable of decomposing into NH3 and CO2 in hydrothermal treatment and the hydrothermal reaction temperature, the leaf-shaped aggregate alumina with regular morphology can be obtained, which has the characteristics of uniform particles, high crystallinity and high thermal stability. The leaf-shaped aggregate structure overcomes the shortcomings of general nanosheet-shaped alumina products, such as difficult separation and easy agglomeration at high temperature. The leaf-shaped aggregate alumina of the present application is simple to separate and does not agglomerate at high temperature, and can continue to maintain the nanosheet-shaped morphology, so as to be applied to the hydrogenation reaction of catalyst as an excellent catalyst carrier. In the preparation process of the present application, CO2 gas is introduced, which can effectively neutralize the number of surface hydroxyl groups of the alumina leaf in the crystallization process of the alumina. On the one hand, it reduces the curling phenomenon of the alumina leaf caused by the condensation of hydroxyl groups in the crystallization process, and can effectively control the width of the alumina leaf. On the other hand, it reduces the coordination saturation of hydroxyl groups and aluminum ions, so that the sheet-shaped alumina is conducive to chelation with active metals. In addition, the present application also uses a higher molar ratio of aluminum ions to compounds. The alumina of the present application can effectively improve the dispersion of active metals and the hydrogenation activity and selectivity of the catalyst when used as a hydrogenation carrier. When the leaf-shaped aggregate structure alumina is used as a carrier, the Ni-Zn active component can be well dispersed on the surface of the carrier, so that the active sites are fully exposed, the utilization rate of active atoms is improved, and the hydrogenation performance of the catalyst is improved. The metal-support effect between the leaf-shaped aggregate structure alumina carrier and the Ni-Zn active component is conducive to the excellent activity and stability of the catalyst in the selective hydrogenation reaction of carbon four fraction. In the catalyst system of the present application, the active component Ni is isolated by Zn atoms, and the electron transfer between Ni and Zn increases the electron density on the surface of Ni, which weakens the adsorption of olefins on the rich-electron Ni and makes it easier to desorb from the surface of the catalyst, thereby improving the hydrogenation selectivity of the Ni catalyst. In the catalyst system of the present application, the polymer generation trend on the catalyst is reduced after the Ni active site is isolated by Zn, and the stability of the catalyst is improved. The Ni-Zn catalyst of the present application has high active metal dispersion, hydrogenation activity, selectivity and stability. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 SEM image of the leaf-shaped aggregate structure alumina obtained in Example 1 of the present application;

[0041] Figure 2 SEM image of the ordinary alumina obtained in Comparative Example 1. DETAILED DESCRIPTION

[0042] The application will be described in detail below by examples. It is necessary to point out here that the following examples are only used to further illustrate the application and cannot be understood as limiting the protection scope of the application, and those skilled in the art can make some non-essential improvements and adjustments to the application according to the above content of the application.

[0043] Raw material source: The medicines used in the application are supplied by the National Pharmaceutical Group Chemical Reagent Co., Ltd.; the carbon four fraction rich in butadiene is taken from the ethylene plant of Lanzhou Petrochemical Company, containing 0.1-0.5wt% of butadiene.

[0044] Raw material and product composition: The composition of the industrial cracking carbon four is determined by SH-T 1141-92.

[0045] Monolefin yield = (product monolefin content / raw material monolefin content) x 100%

[0046] Analysis method:

[0047] The following characterization methods are used in the preparation process of the application: the pore volume and specific surface area of the sample are determined on the American Micromeritics Tristar3020 full-automatic physical adsorption instrument; the morphology of the sample is characterized by the German Zeiss scanning electron microscope (SEM).

[0048] Hydrogen-oxygen titration for dispersity: hydrogen-oxygen titration for dispersity is carried out on the micromeritics Autochem2920 chemical adsorption instrument. 0.2g of sample is reduced at a certain temperature for 2 hours, then cooled to 30℃, and argon is blown for 60min. Oxygen adsorption: 5% O2-Ar is introduced for 60min; hydrogen titration: 5% H2-Ar is titrated by LOOP ring injection, and when the peak height is unchanged, TCD detector is used for detection.

[0049] The application will be further illustrated by examples below, but it is not considered that the application is limited to this.

[0050] Example 1

[0051] (1) Preparation of the carrier

[0052] Aluminum sulfate and ammonium carbonate (the molar ratio of aluminum ions to ammonium carbonate is 2.5) are added to deionized water, stirred and dissolved, then transferred into an autoclave, CO2 gas is introduced to 1MPa, reacted at 160℃ in the autoclave for 10h, cooled to room temperature, and the precipitate is separated, washed and dried. The prepared product is mixed with 3wt% of nitric acid based on the total weight of the sample to be shaped, 2wt% of sesbania powder based on the total weight of the sample to be shaped and water to form a plastic body, extruded into strips, then dried at 120℃ for 4h and calcined at 800℃ for 4h to obtain a leaf-shaped aggregate alumina carrier. Scanning electron microscopy of the carrier shows a leaf-shaped structure, as shown inFigure 1 as shown.

[0053] (2) Catalyst preparation

[0054] The carrier prepared in (1) was weighed at 100 g, and nickel nitrate, zinc nitrate and cerium nitrate were accurately weighed, with the amount being such that the final catalyst contains 15 wt% of nickel oxide, 0.1 wt% of zinc oxide and 0.2 wt% of cerium oxide. The catalyst was prepared by a two-step impregnation method: in the first step, the nickel nitrate, zinc nitrate and cerium nitrate were dissolved in water to form an impregnation solution, which was impregnated onto the carrier by the equal-volume impregnation method, with the total amount of impregnated nickel nitrate being 35 wt%, followed by drying at 120°C and calcination at 300°C for 3 h; in the second step, the equal-volume impregnation method was used to impregnate the total amount of 65 wt% of nickel nitrate, followed by drying at 120°C and calcination at 300°C for 3 h, to obtain the catalyst C1.

[0055] Example 2

[0056] (1) Carrier preparation

[0057] Aluminum nitrate and ammonium bicarbonate (molar ratio of aluminum ions to ammonium bicarbonate being 0.5) were added to deionized water, which was stirred and dissolved, and then transferred into an autoclave, into which CO2 gas was introduced to 1.2 MPa. The mixture was reacted at 200°C in the autoclave for 6 h, and then cooled to room temperature. The precipitate was separated by filtration, washed and dried, to obtain a product. The product was mixed with 5 wt% of phosphoric acid based on the total weight of the sample to be formed, 2.5 wt% of sesbania powder based on the total weight of the sample to be formed and water, to form a kneadable body, which was extruded into a strip, dried at 120°C for 4 h and calcined at 850°C for 5 h, to obtain a leaf-shaped aggregate alumina carrier.

[0058] (2) Catalyst preparation

[0059] The carrier prepared in (1) was weighed at 100 g, and nickel nitrate, zinc nitrate and cerium nitrate were accurately weighed, with the amount being such that the final catalyst contains 15 wt% of nickel oxide, 0.1 wt% of zinc oxide and 0.2 wt% of cerium oxide. The catalyst was prepared by a two-step impregnation method: in the first step, the nickel nitrate, zinc nitrate and cerium nitrate were dissolved in water to form an impregnation solution, which was impregnated onto the carrier by the equal-volume impregnation method, with the total amount of impregnated nickel nitrate being 35 wt%, followed by drying at 120°C and calcination at 300°C for 3 h; in the second step, the equal-volume impregnation method was used to impregnate the total amount of 65 wt% of nickel nitrate, followed by drying at 120°C and calcination at 300°C for 3 h, to obtain the catalyst C1.

[0060] Example 3

[0061] (1) Carrier preparation

[0062] Aluminum chloride and urea (molar ratio of aluminum ion to urea is 2) were added into deionized water, after stirring and dissolving, the mixture was transferred into an autoclave, CO2 gas was introduced to 1.5 MPa, and the mixture was reacted at 180°C for 8 h in the autoclave. After cooling to room temperature, the precipitate was separated by filtration, washed, and dried. The obtained product was mixed with 4 wt% of hydrochloric acid based on the total weight of the sample to be shaped, 3 wt% of sesbania powder based on the total weight of the sample to be shaped, and water to form a plastic body. The plastic body was extruded into a strip, dried at 120°C for 4 h, and calcined at 900°C for 4 h to obtain a leaf-shaped aggregate alumina carrier.

[0063] (2) Catalyst preparation

[0064] 100 g of the carrier prepared in (1) was weighed, and nickel chloride, zinc sulfate, and cerium nitrate were accurately weighed so that the final catalyst contained 20 wt% of nickel oxide, 3 wt% of zinc oxide, and 2.5 wt% of cerium oxide. The catalyst was prepared by a two-step impregnation method: in the first step, nickel chloride, zinc sulfate, and cerium nitrate were dissolved in water to form an impregnation solution, which was impregnated onto the carrier by the equal volume impregnation method, and the total amount of impregnated nickel chloride was 35 wt%. After drying at 120°C and calcination at 400°C for 5 h, the second step was performed by the equal volume impregnation method to impregnate the total amount of 65 wt% of nickel chloride. After drying at 120°C and calcination at 400°C for 5 h, catalyst C3 was obtained.

[0065] Example 4

[0066] (1) Carrier preparation

[0067] Aluminum nitrate and ammonium oxalate (molar ratio of aluminum ion to ammonium oxalate is 3.5) were added into deionized water, after stirring and dissolving, the mixture was transferred into an autoclave, CO2 gas was introduced to 1.8 MPa, and the mixture was reacted at 120°C for 4 h in the autoclave. After cooling to room temperature, the precipitate was separated by filtration, washed, and dried. The obtained product was mixed with 8 wt% of sulfuric acid based on the total weight of the sample to be shaped, 3.5 wt% of sesbania powder based on the total weight of the sample to be shaped, and water to form a plastic body. The plastic body was extruded into a strip, dried at 120°C for 4 h, and calcined at 950°C for 5 h to obtain a leaf-shaped aggregate alumina carrier.

[0068] (2) Catalyst preparation

[0069] 100 g of the carrier prepared in (1) was weighed, and nickel sulfate, zinc acetate, and lanthanum nitrate were accurately weighed so that the final catalyst contained 19 wt% of nickel oxide, 4.5 wt% of zinc oxide, and 2.5 wt% of lanthanum oxide. The catalyst was prepared by a two-step impregnation method: in the first step, nickel sulfate, zinc acetate, and lanthanum nitrate were dissolved in water to form an impregnation solution, which was impregnated onto the carrier by the equal volume impregnation method, and the total amount of impregnated nickel sulfate was 35 wt%. After drying at 120°C and calcination at 450°C for 6 h, the second step was performed by the equal volume impregnation method to impregnate the total amount of 65 wt% of nickel sulfate. After drying at 120°C and calcination at 450°C for 6 h, catalyst C4 was obtained.

[0070] Example 5

[0071] (1) Preparation of the carrier

[0072] Aluminum chloride and ammonium bicarbonate (molar ratio of aluminum ion to ammonium bicarbonate was 4) were added to deionized water, and after stirring and dissolving, the mixture was transferred into an autoclave, CO2 gas was introduced to 2 MPa, and the mixture was reacted at 160°C in the autoclave for 15 h. After cooling to room temperature, the precipitate was separated by filtration, washed, and dried. The obtained product was mixed with 9 wt% of hydrochloric acid based on the total weight of the sample to be shaped, 4 wt% of the amaranth powder based on the total weight of the sample to be shaped, and water to form a plastic body, which was extruded into a strip, dried at 120°C for 4 h, and calcined at 1000°C for 6 h to obtain a leaf-shaped aggregate alumina carrier.

[0073] (2) Preparation of the catalyst

[0074] 100 g of the carrier prepared in (1) was weighed, and nickel nitrate, zinc acetate, and lanthanum nitrate were accurately weighed so that the final catalyst contained 25 wt% of nickel oxide, 4 wt% of zinc oxide, and 1.5 wt% of lanthanum oxide. The catalyst was prepared by a two-step impregnation method: in the first step, nickel nitrate, zinc acetate, and lanthanum nitrate were dissolved in water to form an impregnation solution, which was impregnated onto the carrier by the equal volume impregnation method, and the total amount of impregnated nickel nitrate was 35 wt%. After drying at 120°C and calcination at 500°C for 7 h, the second step was performed by the equal volume impregnation method to impregnate the total amount of 65 wt% of nickel nitrate, and then the mixture was dried at 120°C and calcined at 500°C for 7 h to obtain catalyst C5.

[0075] Example 6

[0076] (1) Preparation of the carrier

[0077] Aluminum sulfate and urea (molar ratio of aluminum ion to urea was 0.1) were added to deionized water, and after stirring and dissolving, the mixture was transferred into an autoclave, CO2 gas was introduced to 0.5 MPa, and the mixture was reacted at 150°C in the autoclave for 24 h. After cooling to room temperature, the precipitate was separated by filtration, washed, and dried. The obtained product was mixed with 10 wt% of phosphoric acid based on the total weight of the sample to be shaped, 4.5 wt% of the amaranth powder based on the total weight of the sample to be shaped, and water to form a plastic body, which was extruded into a strip, dried at 120°C for 4 h, and calcined at 800°C for 6 h to obtain a leaf-shaped aggregate alumina carrier.

[0078] (2) Preparation of the catalyst

[0079] Take the carrier prepared in (1) 100 g, accurately weigh the nickel acetate, zinc sulfate, cerium nitrate, lanthanum nitrate, the amount of which makes the final catalyst contain 16 wt% of nickel oxide, 0.2 wt% of zinc oxide, 0.1 wt% of cerium oxide, and 0.1 wt% of lanthanum oxide. A two-step impregnation method is used to prepare the catalyst: in the first step, nickel acetate, zinc sulfate, cerium nitrate, and lanthanum nitrate are dissolved in water to form an impregnation solution, which is impregnated onto the carrier using the equal volume impregnation method, with a total of 35 wt% of nickel nitrate impregnated, dried at 120°C, and calcined at 380°C for 8h; in the second step, an equal volume of nickel acetate is impregnated, with a total of 65 wt% of nickel acetate impregnated, dried at 120°C, and calcined at 380°C for 8h, to obtain catalyst C5.

[0080] Example 7

[0081] (1) Carrier preparation

[0082] Aluminum nitrate and ammonium carbonate (molar ratio of aluminum ions to ammonium carbonate is 3) are added to deionized water, stirred and dissolved, then transferred to an autoclave, CO2 gas is introduced to 0.8 MPa, and reacted at 200°C for 18h in the autoclave. After cooling to room temperature, the precipitate is separated by filtration, washed, and dried. The prepared product is mixed with 3.5wt% of nitric acid based on the total weight of the sample to be formed, 5wt% of sesbania powder based on the total weight of the sample to be formed, and water to form a plastic body. The plastic body is extruded into strips, dried at 120°C for 4h, and calcined at 880°C for 5h to obtain a leaf-shaped aggregate alumina carrier.

[0083] (2) Catalyst preparation

[0084] Take the carrier prepared in (1) 100 g, accurately weigh the nickel chloride and zinc chloride, the amount of which makes the final catalyst contain 17 wt% of nickel oxide and 0.2 wt% of zinc oxide. A three-step impregnation method is used to prepare the catalyst: in the first step, nickel chloride and zinc chloride are dissolved in water to form an impregnation solution, which is impregnated onto the carrier using the equal volume impregnation method, with a total of 35 wt% of nickel chloride impregnated, dried at 120°C, and calcined at 420°C for 6h; in the second step, an equal volume of nickel chloride is impregnated, with a total of 65 wt% of nickel chloride impregnated, dried at 120°C, and calcined at 420°C for 6h, to obtain a semi-finished catalyst; in the third step, accurately weigh the cerium nitrate and lanthanum nitrate, the amount of which makes the final catalyst contain 1 wt% of cerium oxide and 1.5 wt% of lanthanum oxide, dissolve in deionized water to make the volume of the obtained impregnation solution equal to the saturated water absorption of the semi-finished catalyst, and impregnate onto the catalyst carrier using the equal volume impregnation method, dried at 120°C, and calcined at 420°C for 6h to obtain catalyst C7.

[0085] Example 8

[0086] (1) Carrier preparation

[0087] Aluminum sulfate, aluminum nitrate (molar ratio of aluminum sulfate to aluminum nitrate is 1.5) and ammonium bicarbonate (molar ratio of aluminum ion to ammonium bicarbonate is 0.5) were added into deionized water, after stirring and dissolving, the solution was transferred into an autoclave, CO2 gas was introduced to 2 MPa, and the solution was reacted at 120°C for 10 h in the autoclave. After cooling to room temperature, the precipitate was separated by filtration, washed and dried. The prepared product was mixed with 5.5 wt% of nitric acid and phosphoric acid (mass ratio of nitric acid to phosphoric acid is 1) based on the total weight of the sample to be shaped, 5.5 wt% of sesbania powder and water based on the total weight of the sample to be shaped, and kneaded into a plastic body, extruded into a strip, and then dried at 120°C for 4 h and calcined at 900°C for 6 h to obtain a leaf-shaped aggregate alumina carrier.

[0088] (2) Catalyst preparation

[0089] 100 g of the carrier prepared in (1) was weighed, and nickel sulfate and zinc sulfate were accurately weighed so that the final catalyst contained 16 wt% of nickel oxide and 0.2 wt% of zinc oxide. The catalyst was prepared by a two-step impregnation method: in the first step, nickel sulfate and zinc sulfate were dissolved in water to prepare an impregnation solution, which was impregnated onto the carrier by an equal volume impregnation method, 35 wt% of the total amount of nickel sulfate was impregnated, dried at 120°C, and calcined at 320°C for 4 h; in the second step, 65 wt% of the total amount of nickel sulfate was impregnated by an equal volume method, dried at 120°C, and calcined at 320°C for 4 h to obtain catalyst C8.

[0090] Example 9

[0091] (1) Carrier preparation

[0092] Aluminum chloride, ammonium carbonate and urea (molar ratio of aluminum ion to ammonium carbonate and urea is 2, molar ratio of ammonium carbonate to urea is 1) were added into deionized water, after stirring and dissolving, the solution was transferred into an autoclave, CO2 gas was introduced to 1 MPa, and the solution was reacted at 140°C for 12 h in the autoclave. After cooling to room temperature, the precipitate was separated by filtration, washed and dried. The prepared product was mixed with 5.5 wt% of nitric acid and phosphoric acid (mass ratio of nitric acid to phosphoric acid is 0.5) based on the total weight of the sample to be shaped, 6 wt% of sesbania powder based on the total weight of the sample to be shaped, and water, and kneaded into a plastic body, extruded into a strip, and then dried at 120°C for 4 h and calcined at 1000°C for 4 h to obtain a leaf-shaped aggregate alumina carrier.

[0093] (2) Catalyst preparation

[0094] 100 g of the carrier prepared in (1) was weighed, and cerium nitrate and lanthanum nitrate were accurately weighed so that the final catalyst contained 0.7 wt% of lanthanum oxide and 0.8 wt% of cerium oxide. Deionized water was added to dissolve the impregnation solution to a volume of the saturated water absorption of the alumina carrier. The catalyst carrier was impregnated by an equal volume impregnation method, dried at 120°C, and calcined at 470°C for 5 h to obtain a carrier containing lanthanum and cerium.

[0095] Nickel nitrate and zinc nitrate were accurately weighed, and the amount of the two was such that the final catalyst contained 10wt% of nickel oxide and 5wt% of zinc oxide. The catalyst was prepared by a two-step impregnation method: in the first step, nickel nitrate and zinc nitrate were dissolved in water to form an impregnation solution, which was impregnated onto the carrier by the equal-volume impregnation method, and the total amount of impregnated nickel nitrate was 35wt%. After drying at 120°C and calcination at 470°C for 5h, the second step was performed by impregnating the equal-volume amount of nickel nitrate, and the total amount of impregnated nickel nitrate was 65wt%. After drying at 120°C and calcination at 470°C for 5h, catalyst C9 was obtained.

[0096] Comparative Example 1

[0097] (1) Preparation of carrier

[0098] Commercially available industrial pseudo-boehmite prepared by carbonization method was mixed with 3wt% of nitric acid based on the total weight of the sample to be formed and 2wt% of sesbania powder based on the total weight of the sample to be formed, and water to form a plastic body, which was extruded into a strip, then dried at 120°C for 4h and calcined at 800°C for 4h to obtain an alumina carrier. Scanning electron microscopy of the carrier showed that the alumina carrier had irregular morphology and agglomeration, as shown in FIG. 1. Figure 2

[0099] (2) Preparation of catalyst

[0100] 100g of the carrier prepared in (1) was used to prepare catalyst D1 by the same method as in Example 1.

[0101] Comparative Example 2

[0102] (1) Preparation of carrier

[0103] Commercially available industrial pseudo-boehmite prepared by nitric acid method was mixed with 5wt% of phosphoric acid based on the total weight of the sample to be formed and 2.5wt% of sesbania powder based on the total weight of the sample to be formed, and water to form a plastic body, which was extruded into a strip, then dried at 120°C for 4h and calcined at 850°C for 5h to obtain an alumina carrier.

[0104] (2) Preparation of catalyst

[0105] 100g of the carrier prepared in (1) was used to prepare catalyst D2 by the same method as in Example 2.

[0106] Comparative Example 3

[0107] (1) Preparation of carrier

[0108] Commercially available industrial pseudo-boehmite prepared by sulfuric acid method was mixed with 4wt% of hydrochloric acid based on the total weight of the sample to be formed and 3wt% of sesbania powder based on the total weight of the sample to be formed, and water to form a plastic body, which was extruded into a strip, then dried at 120°C for 4h and calcined at 900°C for 4h to obtain a leaf-shaped aggregate alumina carrier.​

[0109] (2) Catalyst preparation

[0110] 100 g of the support prepared in (1) was weighed, and a catalyst D3 was prepared by the same preparation method as in Example 3.

[0111] Comparative Example 4

[0112] (1) Support preparation

[0113] Aluminum nitrate and ammonium oxalate (molar ratio of aluminum ions to ammonium oxalate: 3.5) were added to deionized water, and after stirring and dissolving, the mixture was transferred to an autoclave, CO2 gas was introduced to 1.8 MPa, and the mixture was reacted at 100°C for 4 h in the autoclave. After cooling to room temperature, the precipitate was separated by filtration, washed, and dried. The resulting product was mixed with 8 wt% of sulfuric acid based on the total weight of the sample to be formed, 3.5 wt% of sesbania powder based on the total weight of the sample to be formed, and water to form a plastic mass, which was extruded into a strip, dried at 120°C for 4 h, and calcined at 950°C for 5 h to obtain a leaf-shaped aggregate alumina support.

[0114] (2) Catalyst preparation

[0115] Comparative Example 5

[0116] (1) Support preparation

[0117] Aluminum chloride and ammonium hydrogen carbonate (molar ratio of aluminum ions to ammonium hydrogen carbonate: 4.5) were added to deionized water, and after stirring and dissolving, the mixture was transferred to an autoclave, CO2 gas was introduced to 2 MPa, and the mixture was reacted at 160°C for 15 h in the autoclave. After cooling to room temperature, the precipitate was separated by filtration, washed, and dried. The resulting product was mixed with 9 wt% of hydrochloric acid based on the total weight of the sample to be formed, 4 wt% of sesbania powder based on the total weight of the sample to be formed, and water to form a plastic mass, which was extruded into a strip, dried at 120°C for 4 h, and calcined at 1000°C for 6 h to obtain a leaf-shaped aggregate alumina support.

[0118] (2) Catalyst preparation

[0119] 100 g of the support prepared in (1) was weighed, and a catalyst D5 was prepared by the same preparation method as in Example 5.

[0120] Table 1: Catalyst properties of Examples and Comparative Examples

[0121]

[0122] The physical parameters of the catalysts of the examples and comparative examples are shown in Table 1. Catalysts C1-C9 are from Examples 1-9, and comparative catalysts D1-D5 are from Comparative Examples 1-5. As shown in the pore volume and specific surface area of the catalysts in Table 1, the catalysts of the present application have greater pore volume and specific surface area, which is advantageous for catalytic hydrogenation reactions. Catalyst C8 was prepared without adding cerium and / or lanthanum, and the metal dispersion of the catalyst was significantly reduced.

[0123] Catalytic performance of the catalysts:

[0124] Catalyst evaluation conditions: A fixed bed reactor was used for isothermal operation, and the catalyst was loaded in a volume of 50 mL. The catalyst was reduced at 130°C under H2for 10 h. The reaction temperature was 40°C, the reaction pressure was 1.5 MPa, the molar ratio of hydrogen to butadiene in the feed was 2, and the liquid hourly space velocity (LHSV) of the feed was 6 h-1. -1 The composition of the hydrogenated product was analyzed by gas chromatography. The composition of the carbon four feed used for catalyst evaluation is shown in Table 2, and the results of the activity and selectivity evaluation of the catalysts are shown in Table 3.

[0125] Table 2 Composition of the carbon four feed

[0126] Component Mass fraction / % Isobutane 58.28 n-Butane 8.49 Trans-butene 9.08 n-Butene 14.01 Isobutene 5.83 Cis-butene 3.67 Butadiene 0.3122

[0127] Table 3 Evaluation results of the catalysts

[0128]

[0129] The evaluation results of the catalysts are shown in Table 2. The main indicators of the evaluation results are the yields of butadiene and mono-olefins in the hydrogenated product. As shown by the comparison of the evaluation results of the catalysts of the examples and comparative examples, the catalysts of the present application exhibit excellent butadiene selective hydrogenation activity and mono-olefin selectivity when used for the selective hydrogenation of the carbon four fraction to recover butadiene under the same process conditions.

[0130] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications to the present application without departing from the spirit and essence of the present application. However, these corresponding changes and modifications should all fall within the scope of protection of the claims of the present application.

Claims

1. A selective hydrogenation catalyst for C4 fractions, characterized in that, Using alumina with a leaf-like aggregate structure as a support, the catalyst, based on 100% of its total mass, comprises 10–25 wt% nickel oxide, 0.1–5 wt% zinc oxide, 0–2.5 wt% cerium oxide and / or lanthanum oxide, with the balance being the support. The catalyst has a specific surface area of ​​60–150 m². 2 / g, pore volume of 0.30~0.50 cm³ 3 / g; The method for preparing the leaf-shaped aggregate structure alumina is as follows: Step (1): Dissolve the inorganic aluminum salt and the compound that can decompose into NH3 and CO2 in water to form a mixed solution; 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. The molar ratio of aluminum ions in the inorganic aluminum salt to compounds that can decompose into NH3 and CO2 in hydrothermal treatment is 0.1 to 4.

2. The C4 fraction selective hydrogenation catalyst according to claim 1, characterized in that, Using alumina with a leaf-like aggregate structure as a support, the catalyst contains 15-20 wt% nickel oxide, 0.2-4.5 wt% zinc oxide, 0.1-1.5 wt% cerium oxide and / or lanthanum oxide, with the balance being the support, based on 100% of the total catalyst mass.

3. The C4 fraction selective hydrogenation catalyst according to claim 1, characterized in that, Nickel oxide and zinc oxide are obtained by introducing soluble nickel salt and soluble zinc salt into a carrier, wherein the soluble nickel salt is one or more of nickel nitrate, nickel acetate, nickel chloride and nickel sulfate; the soluble zinc salt is one or more of zinc chloride, zinc sulfate, zinc nitrate and zinc acetate; and the cerium and / or lanthanum are added in the form of soluble nitrate.

4. The C4 fraction selective hydrogenation catalyst according to claim 3, characterized in that, The soluble nickel salt is nickel nitrate; the soluble zinc salt is zinc nitrate.

5. The C4 fraction selective hydrogenation catalyst according to claim 1, characterized in that, In step (2), the pressure of CO2 introduced is 0.2 to 1 MPa.

6. The C4 fraction selective hydrogenation catalyst according to claim 1, characterized in that, The compounds that can decompose into NH3 and CO2 in step (1) are one or more of ammonium carbonate, ammonium bicarbonate, urea and ammonium oxalate.

7. The C4 fraction selective hydrogenation catalyst according to claim 1, characterized in that, The molar ratio of aluminum ions in the inorganic aluminum salt to compounds that can decompose into NH3 and CO2 in hydrothermal treatment is 0.5 to 3.

8. The C4 fraction selective hydrogenation catalyst according to claim 1, characterized in that, The inorganic aluminum salt mentioned in step (1) is one or more of aluminum sulfate, aluminum nitrate and aluminum chloride.

9. The C4 fraction selective hydrogenation catalyst according to claim 1, characterized in that, In step (2), the hydrothermal time is 4 to 24 hours; the calcination temperature is 800 to 1000℃ and the calcination time is 4 to 6 hours.

10. The application of the selective hydrogenation catalyst for C4 fraction according to any one of claims 1 to 9, characterized in that, The catalyst is reduced with hydrogen at 380~450℃ for 6~16h and then used for selective hydrogenation of C4 fraction.

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