A catalyst for selective hydrogenation of carbon four alkyne and a preparation method thereof

Abstract

The application discloses a kind of carbon four alkynyl selective hydrogenation catalyst and preparation method thereof, the preparation method includes: the soluble precursor of Ni and the soluble precursor of Cu are dissolved in water, stirring is formed microemulsion, carrier after high-temperature calcination is added to prepared microemulsion and impregnated, dry, calcination, obtain semi-finished product catalyst A;The soluble precursor of Pd is dissolved in water, then semi-finished product catalyst A is added to Pd-containing solution and impregnated, dry, calcination, obtain semi-finished product catalyst B;The soluble precursor of Ce and the soluble precursor of Pt are dissolved in deionized water, semi-finished product catalyst B is impregnated in the solution containing Ce and Pt, after solution is all absorbed, dry, calcination, obtain semi-finished product catalyst C;The soluble precursor of Pb is dissolved in deionized water;Semi-finished product catalyst C is impregnated in the solution containing Pb, after solution is completely absorbed, dry, calcination, obtain final catalyst.

Description

TECHNICAL FIELD

[0001] The present application relates to a carbon four alkyne selective hydrogenation catalyst and a preparation method thereof, in particular to a cracking mixed carbon four fraction selective hydrogenation acetylene removal catalyst and a preparation method thereof. BACKGROUND

[0002] Ethylene production device of hydrocarbon steam cracking usually produces 10% to 15% of mixed carbon four fraction by mass fraction, which contains 40% to 60% of 1,3-butadiene and 0.5% to 2.0% of alkyne. When butadiene extraction is carried out, tail gas with high alkyne content is produced, which is easy to cause fire and explosion, and has certain safety hidden danger. Production units usually dilute alkyne to a safe range by using a large amount of butene and butane, and then discharge the tail gas to a flare or sell it at a low price, which brings certain economic loss and environmental pollution. Hydrogenation technology can be used to hydrogenate the material containing alkyne into butadiene, butene and butane, which is a main way to improve the added value of butadiene device. The economic benefit brought by the route of selective hydrogenation of carbon four alkyne to butadiene is more considerable. The technology of selective hydrogenation of carbon four alkyne to recover butadiene includes three process routes of front hydrogenation technology, back hydrogenation technology and mixed hydrogenation technology. Compared with back hydrogenation, the front hydrogenation process route can save the second extraction distillation system, simplify the production process and reduce the production energy consumption, but the butadiene loss is generally greater than 2%, so the catalyst is required to have high selectivity.

[0003] Chinese patent CN102249838A discloses a selective hydrogenation method of alkyne in carbon four hydrocarbon stream and a supported palladium catalyst. The crystal face state of palladium site is controlled by using ionizing radiation and adding free radical cleaning agent in the catalyst preparation process, so as to improve the selectivity of the catalyst to alkyne. The selectivity of the catalyst to alkyne can reach 74.11%, but the patent does not give detailed description of the long-period operation stability of the catalyst.

[0004] Chinese patent CN102886262A discloses a catalyst using Ni-Cu bimetallic active element, in which the content of Ni is 10% to 20%, the content of Cu is 3% to 10%, and the rest is alumina carrier. The selectivity of the catalyst to EA (butyne) and VA (vinyl acetylene) can reach 90% and 84.1%, but the butadiene is greatly lost, and the butadiene is reduced by 67.5% in the whole reaction process.

[0005] Chinese patent CN106552647B discloses a catalyst preparation method, a copper-aluminum alloy is mixed with a solution containing caustic soda to obtain a Raney copper catalyst; then the Raney copper catalyst is contacted with a solution containing silver ions to obtain a silver-modified Raney copper catalyst. The catalyst has high selectivity and high catalytic efficiency, and can significantly improve the reaction space velocity when selectively hydrogenating carbon four fraction to remove acetylene, but the catalyst preparation process is relatively complex, and the catalyst activity is slightly insufficient.

[0006] Chinese patent CN103418378B relates to a carbon four fraction selective hydrogenation acetylene removal catalyst and its preparation method. The catalyst carrier is alumina, Pd is the main active component, and Fe, Ni and La are the auxiliary active components. The catalyst is simple to prepare, has high hydrogenation acetylene removal activity and high reaction volume space velocity, and has the advantage of long regeneration cycle, but the selectivity of the catalyst is not ideal, and the butadiene loss rate is high during hydrogenation.

[0007] Chinese patent CN102463117B relates to an acetylene selective hydrogenation catalyst and its preparation method. The catalyst carrier uses titanium oxide-alumina composite oxide carrier, Cu is the main active component, and Co, lanthanide metal, Ni and Zn are the auxiliary active components. The catalyst has good selectivity and strong anti-poisoning ability, but the long-term operation stability of the catalyst needs to be improved, which is difficult to meet the needs of industrial application.

[0008] Chinese patent CN201911000611.5 discloses a carbon four acetylene selective hydrogenation butadiene catalyst and its preparation method. The catalyst uses ZrO2 / CdO / Bi2O3 composite carrier, Pd is the main active component, and group VII B metal and La are the auxiliary active components. The catalyst has good selectivity and stability, but the catalyst carrier preparation process is complex, the catalyst preparation period is long, which limits its application in industry.

[0009] Chinese patent CN104096573B discloses a preparation method of a high anti-coking selective hydrogenation catalyst. The catalyst carrier is mainly alumina and has a bimodal pore distribution structure, contains double active components Pd and Ni, and the active component palladium is mainly distributed on the surface of the carrier, especially in small pores, while the anti-coking component Ni is mainly distributed in large pores. The catalyst is particularly suitable for carbon two and carbon three fraction hydrogenation, can significantly reduce the amount of green oil and catalyst coking, prolong the service life of the catalyst, and improve the economic benefits of the device operation.

[0010] Chinese patent CN113663688A discloses a preparation method of a butadiene hydroprocessing catalyst, the carrier of the catalyst is mainly alumina and has a bimodal pore distribution structure, and the active components of the catalyst are mainly Pd, Mo, Ni and Cu, wherein Ni and Cu are loaded in the large pores of the carrier in a microemulsion manner; Mo is loaded by a solution method, and most of Pd is loaded by a solution method, and a small part of Pd is loaded by a microemulsion method. The catalyst is suitable for a butadiene hydroprocessing process and has good hydrogenation activity and high coking resistance.

[0011] For hydrogenation reactions, the hydrogenation catalyst needs to be reduced before being applied, so that the active components exist in the metallic state, thereby making the catalyst have hydrogenation activity. During the high-temperature calcination process of catalyst preparation, metal salts are generally decomposed into metal oxides and form nanosized clusters. Different oxides need to be reduced at different temperatures due to their different chemical properties. For nanosized metals, a temperature of about 200 DEG C is an important critical temperature, and above this temperature, metal particles will significantly aggregate. Therefore, how to reduce the aggregation of the main active components during the reduction process and improve the dispersion of the active metal components is of great significance for hydrogenation catalysts. SUMMARY

[0012] The purpose of the present application is to provide a butadiene selective hydrogenation catalyst and a preparation method thereof. The catalyst prepared by the method has excellent hydrogenation activity, selectivity, operation stability and coking resistance, and can be used for butadiene selective hydrogenation reactions.

[0013] To achieve the above purpose, the present application provides a preparation method of a butadiene selective hydrogenation catalyst, the carrier of the catalyst is mainly alumina and has a bimodal pore structure, and contains active components Pd, Pt, Ni, Cu, Ce and Pb. The preparation method comprises the following steps:

[0014] (1) Dissolve the soluble precursor of Ni and the soluble precursor of Cu in water, add an oil phase, a surfactant and a co-surfactant, stir to form a microemulsion, and then immerse the carrier after high-temperature calcination into the prepared microemulsion, filter out the remaining liquid, dry and calcine to obtain semi-finished catalyst A; the particle size of the microemulsion is greater than the maximum pore size of the small pores of the carrier and less than the maximum pore size of the large pores of the carrier;

[0015] (2) Dissolve the soluble precursor of Pd in water to obtain a Pd-containing solution, the amount of the solution is 100-115% of the saturated water absorption amount of semi-finished catalyst A, adjust the pH to 1-3, and then immerse semi-finished catalyst A in the Pd-containing solution, dry and calcine to obtain semi-finished catalyst B;

[0016] (3) dissolving the soluble precursor of Ce and the soluble precursor of Pt in deionized water together to obtain a solution containing Ce and Pt, the solution amount being 100-115% of the saturated water absorption amount of the semi-finished catalyst B, adjusting the pH to 1-5, immersing the semi-finished catalyst B in the solution containing Ce and Pt, drying and calcining after the solution is completely absorbed to obtain the semi-finished catalyst C;

[0017] (4) dissolving the soluble precursor of Pb in deionized water to obtain a solution containing Pb, the solution amount being 100-115% of the saturated water absorption amount of the semi-finished catalyst C, immersing the semi-finished catalyst C in the solution containing Pb, drying and calcining after the solution is completely absorbed to obtain the final catalyst;

[0018] The surfactant is an ionic surfactant or a non-ionic surfactant, the oil phase is a C6-C8 saturated alkane or a cycloalkane, and the co-surfactant is a C4-C6 alcohol. The weight ratio of the water phase to the oil phase is 1.5-3, the weight ratio of the surfactant to the oil phase is 0.15-0.65, and the weight ratio of the surfactant to the co-surfactant is 1-1.2.

[0019] In the catalyst preparation process, Ni-Cu is impregnated and loaded in the large pores of the carrier in the form of a microemulsion. The particle size of the microemulsion is greater than the pore size of the small pores of the carrier and less than the maximum pore size of the large pores of the carrier. Ni-Cu metal salt is contained in the microemulsion and is difficult to enter the small pores of the carrier due to steric hindrance, and thus mainly enters the large pores of the carrier. The remaining active components are impregnated and loaded in the small pores of the carrier in the form of a solution. Due to the stronger siphon effect of the small pores, the active components such as Pd loaded in the form of a solution are mainly loaded in the small pores of the catalyst.

[0020] Ni-Cu generally needs to be reduced at 350-400℃, but at this relatively high reduction temperature, Pd active centers will obviously aggregate. The inventors found that loading Ni-Cu components in the large pores of the catalyst can reduce the degree of coking on the surface of the catalyst, thereby prolonging the operating life of the catalyst. In addition, after adding Ce during the impregnation of the catalyst, the aggregation degree of Pd during the reduction of the catalyst is alleviated. If Ce and Pt are loaded at the same time, even after more than 5 times of coking, the dispersion degree of the active components is still reduced by not more than 20%. The reason may be that the metal salt of Ce, after calcination, will form an oxide of Ce, which exists in the form of a single layer distribution. When Pt and Ce are co-loaded, Pt is mainly loaded on the oxide of Ce, and it is speculated that Pt 2+ --O 2- -Ce 4+The species, the binding force of which is much higher than the binding force of Pt and alumina, so that the Pt atoms co-loaded with Ce are like "atomic lattice" outside the separately loaded Pt particles, preventing the Pd particles from growing, thus playing a role of improving the high-temperature resistance of the Pd active centers to agglomeration and the dispersion of the active metal components of the catalyst.

[0021] In order to prevent the Pd particles from agglomerating, the Pt and Ce are also loaded by the solution method, so that they are mainly located in the small pores of the catalyst.

[0022] After the main active component Pd is loaded, Pb is loaded by the solution method, which plays a role of forming an alloy with Pd to improve the selectivity of carbon four alkyne hydrogenation.

[0023] In order to prevent the Ni-Cu from entering the small pores and covering the loaded Pd, the solution method for loading Pd is preferably performed after the microemulsion method for loading Ni-Cu. In addition, the loading of Pb is preferably performed after the loading of Pd by the solution method. Preferably, the step (2) can be performed before the step (1) or after the step (1).

[0024] Preferably, the specific surface area of the carrier is 60-160 m 2 / g, the pore size of the small pores in the bimodal pore structure of the carrier is 10-40 nm, the pore size of the large pores is 50-400 nm, and the particle size of the microemulsion is greater than 40 nm and less than 400 nm.

[0025] Preferably, the surfactant is a non-ionic surfactant, more preferably polyethylene glycol octylphenyl ether (Triton X-100) or cetyltrimethylammonium bromide (CTAB); the oil phase is cyclohexane or n-hexane; and the co-surfactant is n-butanol or n-pentanol.

[0026] Preferably, the carrier is alumina or mainly alumina, and the content of alumina in the carrier is preferably more than 80 wt%. The present application does not particularly limit the crystal form of the alumina, and the crystal form of the alumina is preferably γ, θ or a mixed crystal form thereof. In addition, the carrier can also contain other metal oxides such as magnesium oxide and titanium oxide.

[0027] Preferably, the content of Ce is 0.1-0.6 wt%, at which content the Ce can form a single layer of cerium oxide or a non-continuous molecular layer of cerium oxide, and the content of Pt co-impregnated with Ce is 0.003-0.03 wt%, which exists in the form of a single atom and is mainly loaded on the cerium oxide.

[0028] Preferably, the soluble precursor of Pd is at least one of palladium chloride, palladium nitrate; the soluble precursor of Ni is at least one of nickel nitrate hexahydrate, nickel sulfate, nickel chloride; the soluble precursor of Cu is at least one of copper sulfate, copper chloride, copper nitrate; the soluble precursor of Pt is at least one of platinum chloride, chloroplatinic acid; the soluble precursor of Ce is at least one of cerium chloride, cerium nitrate; the soluble precursor of Pb is lead acetate.

[0029] The present application does not particularly limit the conditions of calcination, preferably, in step (1), step (2), step (3) or step (4), the temperature of calcination is 400-600℃, and the time is 3-6 hours.

[0030] The present application does not particularly limit the time of impregnation, preferably, in step (1), step (2), step (3) or step (4), the time of impregnation is 0.5-4 hours.

[0031] Preferably, the shape of the carrier can be spherical, tooth spherical, cylindrical, clover-shaped, four-leaf clover-shaped, etc.

[0032] The present application also provides a carbon four alkyne selective hydrogenation catalyst, comprising a carrier and active components, the catalyst carrier is mainly alumina, having a bimodal pore structure, the active components include Pd, Pt, Ni, Cu, Ce, Pb, the content of Pd is 0.1-0.5%, the content of Ni is 0.5-5%, the content of Cu is 0.1-1.5%, the content of Ce is 0.1-0.6%, the content of Pt is 0.003-0.03%, and the content of Pb is 0.01-3%, based on the mass of the catalyst; wherein Ni and Cu are loaded in the form of microemulsion, and the rest of the active components are loaded in the form of solution, the particle size of the microemulsion is greater than the maximum pore size of the small pores of the carrier and less than the maximum pore size of the large pores of the carrier.

[0033] Preferably, the content of Pd is preferably 0.2-0.4%, the content of Ni is preferably 1-3%, the content of Cu is preferably 0.5-1%, the content of Ce is preferably 0.2-0.4%, the content of Pt is preferably 0.008-0.018%, and the content of Pb is preferably 1-2%, based on the mass of the catalyst.

[0034] Preferably, the reduction temperature of the catalyst is preferably 350-400℃.

[0035] The catalyst prepared by the preparation method has the following characteristics: at the beginning of the hydrogenation reaction, due to the high hydrogenation activity of Pd and the fact that Pd is mainly distributed in the small pores, the selective hydrogenation reaction of carbon four alkyne mainly occurs in the small pores. With the extension of the running time of the catalyst, a part of the by-products with large molecular weight are generated on the surface of the catalyst. Due to the large molecular size, more of these substances enter the large pores and stay for a long time, and under the catalysis of Ni-Cu, the double bond hydrogenation reaction occurs to generate saturated hydrocarbons or aromatic hydrocarbons without isolated double bonds, and it is not easy to generate substances with larger molecular weight. After regeneration of the catalyst, the reduction is still at 350-400 ℃, and the activity and selectivity of the regenerated catalyst do not change significantly. When the content of Ce is high, the amount of green oil generated increases significantly, but the coking of the catalyst does not accelerate significantly. After about 5 times of regeneration, the activity and selectivity of the catalyst do not change significantly.

[0036] The carbon four alkyne selective hydrogenation catalyst and the preparation method thereof can effectively reduce the agglomeration of the main active component during high-temperature reduction, the catalyst is suitable for selective hydrogenation of alkyne in cracked carbon four fraction, and is suitable for the pre-hydrogenation process of carbon four alkyne selective hydrogenation, and has high activity, selectivity, stability and anti-coking performance.

[0037] The selective hydrogenation reaction of carbon four alkyne occurs in the main active center composed of Pd, and the green oil and other macromolecules produced in the reaction are easy to enter the large pores of the catalyst. In the large pores of the catalyst, Ni-Cu components are loaded, and Ni-Cu has a saturated hydrogenation function. The green oil components will undergo saturated hydrogenation reaction in the Ni-Cu active center. Due to the saturation of the double bond by hydrogenation, the green oil components cannot undergo polymerization reaction or the polymerization reaction rate is greatly reduced, the chain growth reaction is terminated or delayed, and large molecular weight condensed ring compounds cannot be formed, which are easy to be carried out of the reactor by the material, so that the coking degree of the surface of the catalyst is greatly reduced, thereby prolonging the running life of the catalyst. DETAILED DESCRIPTION

[0038] The following embodiments of the present application are described in detail: The embodiments are implemented on the premise of the technical solutions of the present application, and detailed implementation methods and processes are given, but the protection scope of the present application is not limited to the following embodiments. The experimental methods not specified in the following embodiments are usually carried out under conventional conditions.

[0039] In the following embodiments, the test methods are conventional methods unless otherwise specified; the reagents and compounds can be obtained by commercial means unless otherwise specified.

[0040] Example 1

[0041] Preparation of the carrier:

[0042] A commercial bimodal pore size distribution spherical alumina support with a diameter of 3 mm was used. After calcination at 900°C for 4 h, the bimodal pore size distribution ranged from 32 to 40 nm and 290 to 397 nm, and the specific surface area was 68 m 2 / g. 100 g of the support was weighed.

[0043] Catalyst preparation:

[0044] (1) 14.86 g of nickel nitrate hexahydrate and 1.26 g of copper sulfate were weighed and dissolved in 80 mL of deionized water, 28 g of n-hexane, 5.5 g of CTAB, and 5 g of n-pentanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 2 hours. The remaining liquid was filtered and removed, and the catalyst was dried at 100°C for 4 hours and calcined at 400°C for 5 hours to obtain a semi-finished catalyst A1.

[0045] (2) 0.17 g of palladium chloride was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst A1, and the pH was adjusted to 2. The semi-finished catalyst A1 was then immersed in the prepared solution and dried at 120°C for 4 hours. The semi-finished catalyst B1 was obtained after calcination at 500°C for 5 hours.

[0046] (3) 0.0525 g of chloroplatinic acid and 0.88 g of cerium chloride were weighed and dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst B1, and the pH was adjusted to 3. The semi-finished catalyst B1 was then immersed in the prepared solution and shaken thoroughly. The solution was dried at 120°C for 4 hours and calcined at 450°C for 4 hours to obtain a semi-finished catalyst C1.

[0047] (4) 1.57 g of lead acetate was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst C1. The semi-finished catalyst C1 was then dissolved in the prepared solution and shaken thoroughly. The solution was dried at 120°C for 4 hours and calcined at 420°C for 6 hours to obtain the final catalyst S1.

[0048] Catalyst reduction:

[0049] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 350°C at a heating rate of 30°C / h, and then maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0050] Example 2

[0051] Support preparation:

[0052] The commercially available bimodal pore size distribution spherical alumina support with a diameter of 3 mm was used. After calcination at 850°C for 4 h, the bimodal pore size distribution range was 24-36 nm and 232-329 nm, and the specific surface area was 93 m2 / g. 100 g of the support was weighed.

[0053] Catalyst preparation:

[0054] (1) 0.83 g of palladium chloride was dissolved in deionized water, and the solution amount was 110% of the saturated water absorption amount of the support. The pH was adjusted to 1.5, and then the support was immersed in the prepared solution. After 2.5 hours of immersion, the support was dried at 120°C for 4 hours, calcined at 600°C for 3.5 hours, and a semi-finished catalyst A2 was obtained.

[0055] (2) 2.64 g of nickel sulfate and 0.63 g of copper chloride were dissolved in 75 mL of deionized water, 28 g of cyclohexane, 8 g of Triton X-100, and 7 g of n-pentanol were added, and a microemulsion was formed by stirring. The semi-finished catalyst A2 was immersed in the prepared microemulsion and shaken for 4 hours. The remaining liquid was filtered out, and the semi-finished catalyst B2 was obtained by drying at 100°C for 4 hours and calcining at 500°C for 3.5 hours.

[0056] (3) 0.042 g of chloroplatinic acid and 0.7 g of cerium nitrate were dissolved in deionized water, and the solution amount was 110% of the saturated water absorption amount of the semi-finished catalyst B2. The pH was adjusted to 2, and then the semi-finished catalyst B2 was immersed in the prepared solution. After shaking, the solution was completely absorbed, and the semi-finished catalyst C2 was obtained by drying at 120°C for 4 hours and calcining at 550°C for 4.5 hours.

[0057] (4) 4.71 g of lead acetate was dissolved in deionized water, and the solution amount was 110% of the saturated water absorption rate of the semi-finished catalyst C2. The semi-finished catalyst C2 was dissolved in the prepared solution, shaken, and the solution was completely absorbed. The final catalyst S2 was obtained by drying at 120°C for 4 hours and calcining at 520°C for 5 hours.

[0058] Catalyst reduction:

[0059] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 380°C at a heating rate of 30°C / h, and then maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0060] Example 3

[0061] Support preparation:

[0062] A commercially available bimodal pore size distribution cloverleaf-shaped alumina support with an outer diameter of 2.5 mm was used. After calcination at 820°C for 4 h, the bimodal pore size distribution ranged from 20 to 32 nm and 191 to 294 nm, and the specific surface area was 108 m 2 / g. 100 g of the support was weighed.

[0063] Catalyst preparation:

[0064] (1) 9.91 g of nickel nitrate hexahydrate and 3.54 g of copper nitrate were weighed and dissolved in 80 mL of deionized water, 35 g of cyclohexane, 12 g of CTAB, and 10 g of n-pentanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 3.5 hours. The remaining liquid was filtered and removed, and the catalyst was dried at 100°C for 4 hours and calcined at 570°C for 4.5 hours to obtain semi-finished catalyst A3.

[0065] (2) 0.7 g of palladium nitrate was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst A3 and the pH was adjusted to 2.5. The semi-finished catalyst A3 was then immersed in the prepared solution and dried at 120°C for 4 hours and calcined at 450°C for 3 hours to obtain semi-finished catalyst B3.

[0066] (3) 0.063 g of chloroplatinic acid and 1.4 g of cerium nitrate were weighed and dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst B3 and the pH was adjusted to 1. The semi-finished catalyst B3 was then immersed in the prepared solution and shaken thoroughly until the solution was completely absorbed. The catalyst was dried at 120°C for 4 hours and calcined at 600°C for 3 hours to obtain semi-finished catalyst C3.

[0067] (4) 3.92 g of lead acetate was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst C3. The semi-finished catalyst C3 was then dissolved in the prepared solution and shaken thoroughly until the solution was completely absorbed. The catalyst was dried at 120°C for 4 hours and calcined at 400°C for 5.5 hours to obtain the final catalyst S3.

[0068] Catalyst reduction:

[0069] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 400°C at a heating rate of 30°C / h and maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0070] Example 4

[0071] Support preparation:

[0072] A commercial spherical alumina support with bimodal pore distribution and a diameter of 3.5 mm was used. After calcination at 800°C for 4 h, the bimodal pore distribution ranged from 18 to 29 nm and from 168 to 273 nm, and the specific surface area was 116 m 2 / g. 100 g of the support was weighed.

[0073] Catalyst preparation:

[0074] (1) 8.83 g of nickel chloride and 3.77 g of copper sulfate were weighed and dissolved in 75 mL of deionized water, 37 g of n-hexane, 15 g of Triton X-100, and 13 g of n-butanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 1 hour. The remaining liquid was filtered and removed, and the support was dried at 100°C for 4 hours and calcined at 450°C for 3 hours to obtain a semi-finished catalyst A4.

[0075] (2) 0.33 g of palladium chloride was weighed and dissolved in deionized water. The amount of the solution was 110% of the saturated water absorption capacity of the semi-finished catalyst A4, and the pH was adjusted to 2. The semi-finished catalyst A4 was then immersed in the prepared solution and dried at 120°C for 4 hours after 2 hours of immersion. The semi-finished catalyst B4 was obtained by calcining at 530°C for 5.5 hours.

[0076] (3) 0.0063 g of chloroplatinic acid and 0.18 g of cerium chloride were weighed and dissolved in deionized water. The amount of the solution was 110% of the saturated water absorption capacity of the semi-finished catalyst B4, and the pH was adjusted to 4. The semi-finished catalyst B4 was then immersed in the prepared solution and shaken thoroughly until the solution was completely absorbed. The semi-finished catalyst C4 was obtained by drying at 120°C for 4 hours and calcining at 400°C for 5 hours.

[0077] (4) 3.14 g of lead acetate was weighed and dissolved in deionized water. The amount of the solution was 110% of the saturated water absorption capacity of the semi-finished catalyst C4. The semi-finished catalyst C4 was then dissolved in the prepared solution and shaken thoroughly until the solution was completely absorbed. The final catalyst S4 was obtained by drying at 120°C for 4 hours and calcining at 550°C for 4.5 hours.

[0078] Catalyst reduction:

[0079] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 390°C at a heating rate of 30°C / h and maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0080] Example 5

[0081] Support preparation:

[0082] Commercially available bimodal spherical alumina carriers with a diameter of 2.5 mm were used. After calcination at 750℃ for 4 hours, the bimodal pore size distribution ranged from 15 to 24 nm and from 106 to 202 nm, with a specific surface area of ​​137 m². 2 / g. Weigh 100g of the carrier.

[0083] Catalyst preparation:

[0084] (1) Weigh 17.34 g of nickel nitrate hexahydrate and 2.36 g of copper nitrate, dissolve them in 70 mL of deionized water, add 40 g of n-hexane, 18 g of CTAB and 15 g of n-butanol, stir thoroughly to form a microemulsion, immerse the prepared carrier in the prepared microemulsion, shake for 3 hours, filter out the residual liquid, dry at 100 °C for 4 hours, calcine at 420 °C for 4 hours to obtain the semi-finished catalyst A5.

[0085] (2) Weigh 0.67g of palladium chloride and dissolve it in deionized water. The solution volume is 100% of the saturated water absorption capacity of the semi-finished catalyst A5. Adjust the pH to 1, then immerse the semi-finished catalyst A5 in the prepared solution. After immersion for 3.5 hours, dry at 120℃ for 4 hours and calcine at 470℃ for 4.5 hours to obtain the semi-finished catalyst B5.

[0086] (3) Weigh 0.0315g of chloroplatinic acid and 0.93g of cerium nitrate, and dissolve them in deionized water. The solution volume is 110% of the saturated water absorption capacity of the semi-finished catalyst B5. Adjust the pH to 2, then immerse the semi-finished catalyst B5 in the prepared solution, shake it thoroughly, and wait for the solution to be completely absorbed. Dry it at 120℃ for 4 hours and calcine it at 500℃ for 4 hours to obtain the semi-finished catalyst C5.

[0087] (4) Weigh 2.35g of lead acetate and dissolve it in deionized water. The solution volume is 115% of the saturated water absorption rate of the semi-finished catalyst C5. Dissolve the semi-finished catalyst C5 in the prepared solution, shake it thoroughly, and wait for the solution to be completely absorbed. Dry it at 120℃ for 4 hours and calcine it at 500℃ for 3.5 hours to obtain the final catalyst S5.

[0088] Catalyst reduction:

[0089] The prepared catalyst was loaded into a fixed-bed reactor, and H2 was introduced at a flow rate of 50 L / h. The system was pressurized to 1.3 MPa, and the catalyst bed was heated to 360 °C at a heating rate of 30 °C / h and maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0090] Example 6

[0091] Carrier preparation:

[0092] A commercial bimodal pore size distribution spherical alumina support with a diameter of 3 mm was used. After calcination at 730°C for 4h, the bimodal pore size distribution ranged from 13 to 22 nm and 86 to 179 nm, and the specific surface area was 146 m 2 / g. 100 g of the support was weighed.

[0093] Catalyst preparation:

[0094] (1) 2.48 g of nickel nitrate hexahydrate and 0.21 g of copper chloride were weighed and dissolved in 75 mL of deionized water, 45 g of cyclohexane, 24 g of CTAB, and 20 g of n-pentanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 2.5 hours. The remaining liquid was filtered and removed, and the catalyst was dried at 100°C for 4 hours and calcined at 600°C for 5.5 hours to obtain a semi-finished catalyst A6.

[0095] (2) 0.47 g of palladium nitrate was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst A6 and the pH was adjusted to 3. The semi-finished catalyst A6 was then immersed in the prepared solution and dried at 120°C for 4 hours after 0.5 hours of immersion. The catalyst was calcined at 400°C for 6 hours to obtain a semi-finished catalyst B6.

[0096] (3) 0.021 g of chloroplatinic acid and 0.47 g of cerium nitrate were weighed and dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst B6 and the pH was adjusted to 3. The semi-finished catalyst B6 was then immersed in the prepared solution and shaken thoroughly until the solution was completely absorbed. The catalyst was dried at 120°C for 4 hours and calcined at 470°C for 4 hours to obtain a semi-finished catalyst C6.

[0097] (4) 0.016 g of lead acetate was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst C6. The semi-finished catalyst C6 was then dissolved in the prepared solution and shaken thoroughly until the solution was completely absorbed. The catalyst was dried at 120°C for 4 hours and calcined at 450°C for 4 hours to obtain the final catalyst S6.

[0098] Catalyst reduction:

[0099] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 370°C at a heating rate of 30°C / h and maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0100] Example 7

[0101] Support preparation:

[0102] A commercially available bimodal pore size distribution clover-shaped strip-shaped alumina support with a diameter of 3 mm was used. After calcination at 700°C for 4 h, the bimodal pore size distribution range was 10-20 nm and 50-138 nm, and the specific surface area was 157 m 2 / g. 100 g of the support was weighed.

[0103] Catalyst preparation:

[0104] (1) 11.04 g of nickel chloride and 3.01 g of copper sulfate were weighed and dissolved in 70 mL of deionized water, 45 g of n-hexane, 28 g of Triton X-100, and 28 g of n-pentanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 0.5 h. The remaining liquid was filtered out, and the catalyst was dried at 100°C for 4 h and calcined at 520°C for 6 h to obtain a semi-finished catalyst A7.

[0105] (2) 0.17 g of palladium chloride was weighed and dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst A7 and the pH was adjusted to 1.5. The semi-finished catalyst A7 was then immersed in the prepared solution and dried at 120°C for 4 h after 3 h of immersion. The catalyst was calcined at 550°C for 4 h to obtain a semi-finished catalyst B7.

[0106] (3) 0.0311 g of platinum chloride and 0.53 g of cerium chloride were weighed and dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst B7 and the pH was adjusted to 5. The semi-finished catalyst B7 was then immersed in the prepared solution and shaken thoroughly until the solution was completely absorbed. The catalyst was dried at 120°C for 4 h and calcined at 580°C for 3 h to obtain a semi-finished catalyst C7.

[0107] (4) 1.88 g of lead acetate was weighed and dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst C7. The semi-finished catalyst C7 was then dissolved in the prepared solution and shaken thoroughly until the solution was completely absorbed. The catalyst was dried at 120°C for 4 h and calcined at 600°C for 3 h to obtain the final catalyst S7.

[0108] Catalyst reduction:

[0109] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 390°C at a heating rate of 30°C / h and maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0110] Comparative Example 1:

[0111] The same support as in Example 1 was used, and the catalyst preparation conditions were the same as in Example 1, except that the step of co-loading Pt and Ce was omitted.

[0112] Support preparation:

[0113] Commercially available bimodal pore size distribution spherical alumina support with a diameter of 3 mm was used. After calcination at 900°C for 4 h, the bimodal pore size distribution ranged from 32 to 40 nm and 290 to 397 nm, and the specific surface area was 68 m 2 / g. 100 g of the support was weighed.

[0114] Catalyst preparation:

[0115] (1) 14.86 g of nickel nitrate hexahydrate and 1.26 g of copper sulfate were weighed and dissolved in 80 mL of deionized water, 28 g of n-hexane, 5.5 g of CTAB, and 5 g of n-pentanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 2 hours. The remaining liquid was filtered and removed, and the catalyst was dried at 100°C for 4 hours and calcined at 400°C for 5 hours to obtain a semi-finished catalyst DA1.

[0116] (2) 0.17 g of palladium chloride was dissolved in deionized water, and the solution was 110% of the saturated water absorption capacity of the semi-finished catalyst DA1. The pH was adjusted to 2, and the semi-finished catalyst DA1 was immersed in the prepared solution. After 1 hour of immersion, the catalyst was dried at 120°C for 4 hours and calcined at 500°C for 5 hours to obtain a semi-finished catalyst DB1.

[0117] (3) 1.57 g of lead acetate was dissolved in deionized water, and the solution was 110% of the saturated water absorption capacity of the semi-finished catalyst DB1. The semi-finished catalyst DB1 was dissolved in the prepared solution and shaken thoroughly. After the solution was completely absorbed, the catalyst was dried at 120°C for 4 hours and calcined at 420°C for 6 hours to obtain the final catalyst D1.

[0118] Catalyst reduction:

[0119] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 350°C at a heating rate of 30°C / h, and then maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0120] Comparative Example 2:

[0121] The same support as in Example 1 was used, and the catalyst preparation conditions were the same as in Example 1, except that only Ce was loaded in the step of loading Pt and Ce.

[0122] Support preparation:

[0123] A commercially available bimodal pore size distribution spherical alumina support with a diameter of 3 mm was used. After calcination at 900°C for 4 h, the bimodal pore size distribution ranged from 32 to 40 nm and 290 to 397 nm, and the specific surface area was 68 m 2 / g. 100 g of the support was weighed.

[0124] Catalyst preparation:

[0125] (1) 14.86 g of nickel nitrate hexahydrate and 1.26 g of copper sulfate were weighed and dissolved in 80 mL of deionized water, 28 g of n-hexane, 5.5 g of CTAB, and 5 g of n-pentanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 2 hours. The remaining liquid was filtered and removed, and the support was dried at 100°C for 4 hours and calcined at 400°C for 5 hours to obtain a semi-finished catalyst DA2.

[0126] (2) 0.17 g of palladium chloride was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst DA2, and the pH was adjusted to 2. The semi-finished catalyst DA2 was then immersed in the prepared solution and dried at 120°C for 4 hours after 1 hour of immersion. The semi-finished catalyst DB2 was obtained by calcining at 500°C for 5 hours.

[0127] (3) 0.88 g of cerium chloride was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst DB2, and the pH was adjusted to 3. The semi-finished catalyst DB2 was then immersed in the prepared solution and shaken thoroughly until the solution was completely absorbed. The semi-finished catalyst DC2 was obtained by drying at 120°C for 4 hours and calcining at 450°C for 4 hours.

[0128] (4) 1.57 g of lead acetate was dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption capacity of the semi-finished catalyst DC2. The semi-finished catalyst DC2 was then dissolved in the prepared solution and shaken thoroughly until the solution was completely absorbed. The final catalyst D2 was obtained by drying at 120°C for 4 hours and calcining at 420°C for 6 hours.

[0129] Catalyst reduction:

[0130] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 350°C at a heating rate of 30°C / h, then maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0131] Comparative Example 3:

[0132] The same support as in Example 3 was used, and the catalyst preparation conditions were the same as in Example 3, except that the solution method for loading the auxiliary component Pb was placed before the solution method for loading the main active component Pd.

[0133] Support preparation:

[0134] Commercially available bimodal pore size distribution clover leaf shaped alumina support with an outer diameter of 2.5 mm was used. After calcination at 820℃ for 4h, the bimodal pore size distribution ranges from 20-32nm and 191-294nm, and the specific surface area is 108m 2 / g. 100g of the support was weighed.

[0135] Catalyst preparation:

[0136] (1) 9.91g of nickel nitrate hexahydrate and 3.54g of copper nitrate were weighed and dissolved in 80mL of deionized water, 35g of cyclohexane, 12g of CTAB and 10g of n-pentanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 3.5 hours. The remaining liquid was filtered out, and the catalyst was dried at 100℃ for 4 hours and calcined at 570℃ for 4.5 hours to obtain a semi-finished catalyst DA3.

[0137] (2) 3.92g of lead acetate was dissolved in deionized water, and the solution volume was 110% of the saturated water absorption of the semi-finished catalyst DA3. The semi-finished catalyst DA3 was dissolved in the prepared solution, and shaken thoroughly. After the solution was completely absorbed, the catalyst was dried at 120℃ for 4 hours and calcined at 400℃ for 5.5 hours to obtain a semi-finished catalyst DB3.

[0138] (3) 0.7g of palladium nitrate was dissolved in deionized water, and the solution volume was 110% of the saturated water absorption of the semi-finished catalyst DB3. The pH was adjusted to 2.5. The semi-finished catalyst DB3 was then immersed in the prepared solution for 4 hours, dried at 120℃ for 4 hours, and calcined at 450℃ for 3 hours to obtain a semi-finished catalyst DC3.

[0139] (4) 0.063g of chloroplatinic acid and 1.4g of cerium nitrate were dissolved in deionized water, and the solution volume was 110% of the saturated water absorption of the semi-finished catalyst DC3. The pH was adjusted to 1. The semi-finished catalyst DC3 was then immersed in the prepared solution, shaken thoroughly, and dried at 120℃ for 4 hours. The catalyst was calcined at 600℃ for 3 hours to obtain the final catalyst D3.

[0140] Catalyst reduction:

[0141] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50L / h, the system was pressurized to 1.3MPa, and the catalyst bed was heated to 400℃ at a heating rate of 30℃ / h, then maintained for 10h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0142] Comparative Example 4:

[0143] The catalyst preparation conditions are the same as those in Example 3, except that the catalyst carrier is a single-peak pore distribution.

[0144] Preparation of the carrier:

[0145] A commercially available single-peak pore distribution clover-shaped strip-shaped alumina carrier with an outer diameter of 2.5 mm is used. After being calcined at 820°C for 4 h, the pore size distribution ranges from 168 to 282 nm, and the specific surface area is 99 m 2 / g. 100 g of the carrier is weighed.

[0146] Catalyst preparation:

[0147] (1) 9.91 g of nickel nitrate hexahydrate and 3.54 g of copper nitrate are weighed and dissolved in 80 mL of deionized water, 35 g of cyclohexane, 12 g of CTAB, and 10 g of n-pentanol are added, and the mixture is stirred to form a microemulsion. The prepared carrier is immersed in the prepared microemulsion and shaken for 3.5 hours. The remaining liquid is filtered out, dried at 100°C for 4 hours, and calcined at 570°C for 4.5 hours to obtain a semi-finished catalyst DA4.

[0148] (2) 0.7 g of palladium nitrate is weighed and dissolved in deionized water, and the solution amount is 110% of the saturated water absorption amount of the semi-finished catalyst DA4. The pH is adjusted to 2.5, and then the semi-finished catalyst DA4 is immersed in the prepared solution. After 4 hours of immersion, the catalyst is dried at 120°C for 4 hours and calcined at 450°C for 3 hours to obtain a semi-finished catalyst DB4.

[0149] (3) 0.063 g of chloroplatinic acid and 1.4 g of cerium nitrate are weighed and dissolved in deionized water, and the solution amount is 110% of the saturated water absorption amount of the semi-finished catalyst DB4. The pH is adjusted to 1, and then the semi-finished catalyst DB4 is immersed in the prepared solution. After shaking, the solution is completely absorbed, and the catalyst is dried at 120°C for 4 hours and calcined at 600°C for 3 hours to obtain a semi-finished catalyst DC4.

[0150] (4) 3.92 g of lead acetate is weighed and dissolved in deionized water, and the solution amount is 110% of the saturated water absorption rate of the semi-finished catalyst DC4. The semi-finished catalyst DC4 is dissolved in the prepared solution, shaken thoroughly, and dried at 120°C for 4 hours. The final catalyst D4 is obtained by calcining at 400°C for 5.5 hours.

[0151] Catalyst reduction:

[0152] The prepared catalyst is loaded into a fixed bed reactor, H2 is introduced at a flow rate of 50 L / h, the system is pressurized to 1.3 MPa, and the catalyst bed is heated to 400°C at a heating rate of 30°C / h, and then maintained for 10 h to reduce the catalyst. After reduction, the temperature is lowered to the reaction temperature for catalyst performance evaluation.

[0153] Comparative Example 5:

[0154] The same carrier as in Example 4 was used, and the catalyst preparation conditions were the same as in Example 4, except that the step of loading Ni-Cu by microemulsion was cancelled.

[0155] Carrier preparation:

[0156] A commercially available bimodal pore distribution spherical alumina carrier with a diameter of 3.5 mm was used. After being calcined at 800°C for 4 h, the bimodal pore size distribution range was 18-29 nm and 168-273 nm, and the specific surface area was 116 m 2 / g. 100 g of the carrier was weighed.

[0157] Catalyst preparation:

[0158] (1) 0.33 g of palladium chloride was dissolved in deionized water, and the solution amount was 110% of the saturated water absorption amount of the carrier, and the pH was adjusted to 2. The carrier was then immersed in the prepared solution, and after 2 hours of immersion, it was dried at 120°C for 4 hours and calcined at 530°C for 5.5 hours to obtain a semi-finished catalyst DA5.

[0159] (2) 0.0063 g of chloroplatinic acid and 0.18 g of cerium chloride were dissolved in deionized water at the same time, and the solution amount was 110% of the saturated water absorption amount of the semi-finished catalyst DA5, and the pH was adjusted to 4. The semi-finished catalyst DA5 was then immersed in the prepared solution, shaken thoroughly, and dried at 120°C for 4 hours after the solution was completely absorbed. It was calcined at 400°C for 5 hours to obtain a semi-finished catalyst DB5.

[0160] (3) 3.14 g of lead acetate was dissolved in deionized water, and the solution amount was 110% of the saturated water absorption rate of the semi-finished catalyst DB5. The semi-finished catalyst DB5 was then dissolved in the prepared solution, shaken thoroughly, and dried at 120°C for 4 hours after the solution was completely absorbed. It was calcined at 550°C for 4.5 hours to obtain the final catalyst D5.

[0161] Catalyst reduction:

[0162] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 390°C at a heating rate of 30°C / h, and then maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0163] Comparative Example 6:

[0164] The same carrier as in Example 5 was used, and the catalyst preparation conditions were the same as in Example 5, except that only Cu was loaded in the step of loading Ni-Cu by microemulsion.

[0165] Carrier preparation:

[0166] A commercially available bimodal pore size distribution spherical alumina support having a diameter of 2.5 mm was used. After calcination at 750°C for 4 h, the bimodal pore size distribution ranged from 15 to 24 nm and 106 to 202 nm, and the specific surface area was 137 m 2 / g. 100 g of the support was weighed.

[0167] Catalyst preparation:

[0168] (1) 2.36 g of copper nitrate was weighed into 70 mL of deionized water, 40 g of n-hexane, 18 g of CTAB, and 15 g of n-butanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 3 hours. The remaining liquid was filtered out, and the support was dried at 100°C for 4 hours and calcined at 420°C for 4 hours to obtain a semi-finished catalyst DA6.

[0169] (2) 0.67 g of palladium chloride was dissolved in deionized water, and the solution was adjusted to 100% of the saturated water absorption of the semi-finished catalyst DA6. The semi-finished catalyst DA6 was then immersed in the prepared solution, and after 3.5 hours of immersion, it was dried at 120°C for 4 hours and calcined at 470°C for 4.5 hours to obtain a semi-finished catalyst DB6.

[0170] (3) 0.0315 g of chloroplatinic acid and 0.93 g of cerium nitrate were simultaneously dissolved in deionized water, and the solution was adjusted to 110% of the saturated water absorption of the semi-finished catalyst DB6. The semi-finished catalyst DB6 was then immersed in the prepared solution, and after being shaken thoroughly, it was dried at 120°C for 4 hours and calcined at 500°C for 4 hours to obtain a semi-finished catalyst DC6.

[0171] (4) 2.35 g of lead acetate was dissolved in deionized water, and the solution was adjusted to 115% of the saturated water absorption of the semi-finished catalyst DC6. The semi-finished catalyst DC6 was then dissolved in the prepared solution, and after being shaken thoroughly, it was dried at 120°C for 4 hours and calcined at 500°C for 3.5 hours to obtain the final catalyst D6.

[0172] Catalyst reduction:

[0173] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 360°C at a heating rate of 30°C / h, then maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0174] Comparative Example 7:

[0175] The same support as in Example 5 was used, and the catalyst preparation conditions were the same as in Example 5, except that only Ni was loaded in the step of loading Ni-Cu in the microemulsion method.

[0176] Support preparation:

[0177] Commercially available bimodal pore size distribution spherical alumina support with a diameter of 2.5 mm was used. After calcination at 750°C for 4 h, the bimodal pore size distribution ranged from 15 to 24 nm and 106 to 202 nm, and the specific surface area was 137 m 2 / g. 100 g of the support was weighed.

[0178] Catalyst preparation:

[0179] (1) 17.34 g of nickel nitrate hexahydrate was weighed into 70 mL of deionized water, 40 g of n-hexane, 18 g of CTAB, and 15 g of n-butanol were added, and the mixture was stirred to form a microemulsion. The prepared support was immersed in the prepared microemulsion and shaken for 3 hours. The remaining liquid was filtered out, and the support was dried at 100°C for 4 hours and calcined at 420°C for 4 hours to obtain a semi-finished catalyst DA7.

[0180] (2) 0.67 g of palladium chloride was dissolved in deionized water, and the solution volume was 100% of the saturated water absorption capacity of the semi-finished catalyst DA7. The pH was adjusted to 1, and the semi-finished catalyst DA7 was then immersed in the prepared solution. After 3.5 hours of immersion, the catalyst was dried at 120°C for 4 hours and calcined at 470°C for 4.5 hours to obtain a semi-finished catalyst DB7.

[0181] (3) 0.0315 g of chloroplatinic acid and 0.93 g of cerium nitrate were simultaneously dissolved in deionized water, and the solution volume was 110% of the saturated water absorption capacity of the semi-finished catalyst DB7. The pH was adjusted to 2, and the semi-finished catalyst DB7 was then immersed in the prepared solution. After shaking, the solution was completely absorbed, and the catalyst was dried at 120°C for 4 hours and calcined at 500°C for 4 hours to obtain a semi-finished catalyst DC7.

[0182] (4) 2.35 g of lead acetate was dissolved in deionized water, and the solution volume was 115% of the saturated water absorption rate of the semi-finished catalyst DC7. The semi-finished catalyst DC7 was then dissolved in the prepared solution and shaken thoroughly. After the solution was completely absorbed, the catalyst was dried at 120°C for 4 hours and calcined at 500°C for 3.5 hours to obtain the final catalyst D7.

[0183] Catalyst reduction:

[0184] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 360°C at a heating rate of 30°C / h, then maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0185] Comparative Example 8:

[0186] The same carrier as in Example 6 was used, except that the step of loading Ni-Cu was performed using a solution method, and the other preparation conditions were the same as in Example 6.

[0187] Carrier preparation:

[0188] A commercially available bimodal pore distribution spherical alumina carrier having a diameter of 3 mm was used. After calcination at 730°C for 4 h, the bimodal pore diameter distribution ranged from 13 to 22 nm and from 86 to 179 nm, and the specific surface area was 146 m 2 / g. 100 g of the carrier was weighed.

[0189] Catalyst preparation:

[0190] (1) 2.48 g of nickel nitrate hexahydrate and 0.21 g of copper chloride were weighed and dissolved in deionized water, and the solution amount was 110% of the saturated water absorption amount of the carrier. The prepared carrier was immersed in the prepared solution, and after 2.5 hours of immersion, it was dried at 100°C for 4 hours and calcined at 600°C for 5.5 hours to obtain a semi-finished catalyst DA8.

[0191] (2) 0.47 g of palladium nitrate was dissolved in deionized water, and the solution amount was 110% of the saturated water absorption amount of the semi-finished catalyst DA8. The pH was adjusted to 3, and then the semi-finished catalyst DA8 was immersed in the prepared solution. After 0.5 hours of immersion, it was dried at 120°C for 4 hours and calcined at 400°C for 6 hours to obtain a semi-finished catalyst DB8.

[0192] (3) 0.021 g of chloroplatinic acid and 0.47 g of cerium nitrate were dissolved in deionized water, and the solution amount was 110% of the saturated water absorption amount of the semi-finished catalyst DB8. The pH was adjusted to 3, and then the semi-finished catalyst DB8 was immersed in the prepared solution. After shaking thoroughly, it was dried at 120°C for 4 hours and calcined at 470°C for 4 hours to obtain a semi-finished catalyst DC8.

[0193] (4) 0.016 g of lead acetate was dissolved in deionized water, and the solution amount was 110% of the saturated water absorption rate of the semi-finished catalyst DC8. The semi-finished catalyst DC8 was dissolved in the prepared solution, shaken thoroughly, and then dried at 120°C for 4 hours and calcined at 450°C for 4 hours to obtain the final catalyst D8.

[0194] Catalyst reduction:

[0195] The prepared catalyst was loaded into a fixed bed reactor, H2 was introduced at a flow rate of 50 L / h, the system was pressurized to 1.3 MPa, and the catalyst bed was heated to 370°C at a heating rate of 30°C / h, and then maintained for 10 h to reduce the catalyst. After reduction, the temperature was lowered to the reaction temperature for catalyst performance evaluation.

[0196] The catalyst composition of the above examples and comparative examples is shown in Table 1.

[0197] Table 1

[0198]

[0199]

[0200] The catalyst evaluation conditions are as follows: a fixed bed reactor is used, isothermal operation, catalyst loading volume is 50 mL, reaction temperature is 55°C, reaction pressure is 1.0 MPa, the molar ratio of hydrogen to acetylene in the raw material is 3, and the liquid hourly space velocity of the material is 3.5 h-1. -1 The composition of the product after hydrogenation is analyzed by gas chromatography. The composition of the carbon four raw material used in the catalyst evaluation is shown in Table 2.

[0201] Table 2

[0202]

[0203]

[0204] The catalyst performance evaluation results of the above examples and comparative examples are shown in Table 3.

[0205] Table 3

[0206]

[0207] Of course, the present application can have other various embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present application without departing from the spirit and essence of the present application, but these corresponding changes and modifications should all belong to the protection scope of the present application.

Claims

1. A method for preparing a selective hydrogenation catalyst for C4-acetylenes, characterized in that, The catalyst support is mainly alumina with a bimodal pore structure. The pore size of the micropores in the bimodal pore structure is 10-40 nm, and the pore size of the macropores is 50-400 nm. The catalyst contains active components Pd, Pt, Ni, Cu, Ce, and Pb. The preparation method includes the following steps: (1) Dissolve Ni soluble precursor and Cu soluble precursor in water, add oil phase, surfactant and co-surfactant, stir to form microemulsion, add the high-temperature calcined support into the prepared microemulsion for impregnation, filter out the residual liquid, dry and calcinate to obtain semi-finished catalyst A; the particle size of the microemulsion is greater than 40 nm and less than 400 nm. (2) Dissolve the soluble precursor of Pd in ​​water to obtain a solution containing Pd. The amount of solution is 100-115% of the saturated water absorption of the semi-finished catalyst A. Adjust the pH to 1-3. Then add the semi-finished catalyst A into the solution containing Pd for impregnation, dry and calcine to obtain the semi-finished catalyst B. (3) Dissolve the soluble precursors of Ce and Pt together in deionized water to obtain a solution containing Ce and Pt. The solution volume is 100-115% of the saturated water absorption capacity of the semi-finished catalyst B. Adjust the pH to 1-5. Immerse the semi-finished catalyst B in the solution containing Ce and Pt. After the solution is completely absorbed, dry and calcine to obtain the semi-finished catalyst C. (4) Dissolve the soluble precursor of Pb in deionized water to obtain a solution containing Pb. The amount of solution is 100-115% of the saturated water absorption of the semi-finished catalyst C. Immerse the semi-finished catalyst C in the solution containing Pb. After the solution is completely absorbed, dry and calcine to obtain the final catalyst. Wherein, the surfactant is an ionic surfactant or a nonionic surfactant, the oil phase is a C6-C8 saturated alkane or cycloalkanes, and the co-surfactant is a C4-C6 alcohol; the weight ratio of the aqueous phase to the oil phase is 1.5-3, the weight ratio of the surfactant to the oil phase is 0.15-0.65, and the weight ratio of the surfactant to the co-surfactant is 1-1.

2.

2. The preparation method according to claim 1, characterized in that, Step (2) is performed before or after step (1).

3. The preparation method according to claim 1, characterized in that, The specific surface area of ​​the carrier is 60–160 m². 2 / g.

4. The preparation method according to claim 1, characterized in that, The surfactant is a nonionic surfactant; the oil phase is cyclohexane or n-hexane; and the co-surfactant is n-butanol or n-pentanol.

5. The preparation method according to claim 4, characterized in that, The surfactant is polyethylene glycol octylphenyl ether Triton X-100 or hexadecyltrimethylammonium bromide CTAB.

6. The preparation method according to claim 1, characterized in that, The alumina in the carrier is above 80 wt%, and the alumina has a crystal form of γ, θ or a mixture thereof.

7. The preparation method according to claim 1, characterized in that, The soluble precursor of Pd is at least one of palladium chloride and palladium nitrate; the soluble precursor of Ni is at least one of nickel nitrate hexahydrate, nickel sulfate, and nickel chloride; the soluble precursor of Cu is at least one of copper sulfate, copper chloride, and copper nitrate; the soluble precursor of Pt is at least one of platinum chloride and chloroplatinic acid; the soluble precursor of Ce is at least one of cerium chloride and cerium nitrate; and the soluble precursor of Pb is lead acetate.

8. The preparation method according to claim 1, characterized in that, In step (1), step (2), step (3) or step (4), the roasting temperature is 400-600℃ and the time is 3-6 hours; in step (1), step (2), step (3) or step (4), the impregnation time is 0.5-4 hours.

9. A selective hydrogenation catalyst for C4-acetylenes obtained by the preparation method according to any one of claims 1-8, characterized in that, The catalyst comprises a support and active components. The support is mainly alumina with a bimodal pore structure. The active components include Pd, Pt, Ni, Cu, Ce, and Pb. Based on 100% of the catalyst mass, the Pd content is 0.1–0.5%, the Ni content is 0.5–5%, the Cu content is 0.1–1.5%, the Ce content is 0.1–0.6%, the Pt content is 0.003–0.03%, and the Pb content is 0.01–3%. Ni and Cu are loaded in a microemulsion manner, while the remaining active components are loaded in solution form. The particle size of the microemulsion is larger than the maximum pore size of the support and smaller than the maximum macropore size of the support.

10. The selective hydrogenation catalyst for C4-acetylenes according to claim 9, characterized in that, Based on the mass of the catalyst (100%), the Pd content is 0.2-0.4%, the Ni content is 1-3%, the Cu content is 0.5-1%, the Ce content is 0.2-0.4%, the Pt content is 0.008-0.018%, and the Pb content is 1-2%.

11. The selective hydrogenation catalyst for C4-acetylenes according to claim 9, characterized in that, The reduction temperature of the catalyst is 350–400°C.

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