C2 selective hydrogenation catalyst and its preparation method and application

Abstract

The present invention relates to the field of carbon two selective hydrogenation catalysts, disclose a carbon two selective hydrogenation catalyst and its preparation method and application. The catalyst contains a carrier and a first active component and a second active component loaded on a carrier, and its characteristic is that the first active component is Pd, and the second active component contains Ag, and in the carbon two selective hydrogenation catalyst, the spacing between the (111) crystal planes of the first active component Pd is 0.228-0.231nm; wherein, in terms of oxide, the content of the first active component is 0.023-0.058 weight %, and the content of the second active component is 0.046-0.172 weight %. The active components of the carbon two selective hydrogenation catalyst are uniformly distributed on the carrier surface, so as to significantly improve catalyst activity, and the preparation method of the catalyst is very simple, and production costs can be significantly reduced.

Description

Technical Field

[0001] The present invention relates to the field of C2 selective hydrogenation catalysts, and in particular to a C2 selective hydrogenation catalyst and a preparation method and application thereof. Background Art

[0002] Petroleum hydrocarbon cracking is the primary technology used in the industrial production of ethylene. During the petroleum hydrocarbon cracking process, the ethylene produced still contains approximately 1% acetylene after undergoing a series of separation steps. While this content is low, it can significantly impact downstream ethylene production. Therefore, C2-selective hydrogenation catalysts are commonly used in industry to remove this small amount of acetylene from ethylene.

[0003] There are a large number of patent reports on the formulation and preparation process of carbon dihydrogenation catalysts.

[0004] For example, CN108014792A discloses a method for preparing a catalyst for selective hydrogenation of carbon distillate: specifically, the method comprises: (1) dissolving a Ga compound in deionized water, impregnating a carrier for 1-24 hours, then directly drying the obtained sample, and calcining it at a temperature of 250-600°C after drying; (2) preparing a Pd compound into a solution, adjusting the pH value to 1.5-5, and loading it onto the precursor obtained in step (1) by spraying or impregnation, and then drying and calcining it; (3) preparing a compound of a metal active component into a solution, impregnating the precursor obtained in step (2), and then drying and calcining it.

[0005] However, the current industrial process for preparing C2 selective hydrogenation catalysts involves separate impregnation, drying, and calcination of the main catalyst and co-catalyst. This process has several drawbacks: a lengthy preparation process; multiple equipment requirements, requiring significant investment and space; high energy consumption, hindering energy conservation and emission reduction; high labor requirements and low productivity; high production costs; and numerous control steps, resulting in inconsistent product quality.

[0006] In order to optimize the above six problems, it is urgent to develop a C2 selective hydrogenation catalyst that can impregnate the main catalyst and the co-catalyst on the carrier at one time. Summary of the Invention

[0007] The present invention aims to overcome the problems of the prior art, such as the long preparation process, high energy consumption, and high cost, of C2-selective hydrogenation catalysts. The present invention provides a C2-selective hydrogenation catalyst, its preparation method, and its application. The active components of the C2-selective hydrogenation catalyst are uniformly distributed on the surface of the support, thereby significantly enhancing the catalyst's activity. Furthermore, the catalyst's preparation method is very simple, significantly reducing production costs.

[0008] The inventors of the present invention have discovered through extensive research that, during the impregnation process, the catalyst support is first modified with PVP (polyvinyl pyrrolidone) and acetylacetone, and the obtained support is then impregnated with active components and additives. This allows the prepared C2 selective hydrogenation catalyst to not only have an excellent acetylene conversion rate, but also significantly improve its ethylene selectivity.

[0009] This may be due to the nitrogen atoms and carbonyl groups in PVP, as well as the carbonyl groups in acetylacetone, which can firmly fix active metal components, particularly Pd and Ag ions. Therefore, by initially coating the support surface with PVP and acetylacetone, the active metal components are secured to the support surface during the subsequent impregnation step, and the PVP and acetylacetone can be completely decomposed and removed during the subsequent calcination step, thus completing the present invention.

[0010] In order to achieve the above-mentioned object, the present invention provides a C2 selective hydrogenation catalyst on one hand, which comprises a carrier and a first active component and a second active component supported on the carrier, wherein the first active component is Pd, the second active component comprises Ag, and in the C2 selective hydrogenation catalyst, the spacing between the (111) crystal planes of the first active component Pd is 0.228-0.231 nm; wherein, calculated as oxide, the content of the first active component is 0.023-0.058 wt%, and the content of the second active component is 0.046-0.172 wt%.

[0011] Preferably, the spacing between the (111) crystal planes of the first active component Pd is 0.228-0.230 nm.

[0012] Preferably, the carrier is one or more of Al2O3, SiO2, MgO, TiO2, molecular sieve and activated carbon; more preferably, the carrier is Al2O3.

[0013] Preferably, the content of the first active component in the catalyst is 0.023-0.046 wt % calculated as oxide.

[0014] Preferably, the second active component further contains Au and / or Cu.

[0015] Preferably, the content of the second active component in the catalyst is 0.060-0.110 wt % calculated as oxide.

[0016] Preferably, the catalyst further contains a promoter; more preferably, the promoter is Bi and / or Ga.

[0017] Preferably, the content of the auxiliary agent in the catalyst is 0.010-0.035 wt % calculated as oxide.

[0018] The second aspect of the present invention provides a method for preparing the C2 selective hydrogenation catalyst according to the first aspect of the present invention, wherein the method comprises the following steps:

[0019] 1) in the presence of a solvent, bringing PVP and acetylacetone into first contact with a catalyst support to obtain a modified support having a surface of the catalyst support at least partially covered with PVP and acetylacetone;

[0020] 2) contacting the modified support obtained in step 1) with a solution containing the first active component and the second active component to obtain a second contact product;

[0021] 3) calcining the second contact product obtained in step 2);

[0022] Wherein, the first active component is Pd, and the second active component contains Ag.

[0023] Preferably, in step 1), the molecular weight of the PVP is less than 10W; more preferably, the molecular weight of the PVP is 0.8W-5W.

[0024] Preferably, in step 2), the second active component further contains Au and / or Cu.

[0025] Preferably, the solution in step 2) further contains an auxiliary agent; more preferably, the auxiliary agent is Bi and / or Ga.

[0026] Preferably, the carrier is one or more of Al2O3, SiO2, MgO, TiO2, molecular sieve and activated carbon; more preferably, the carrier is Al2O3.

[0027] Preferably, in step 1), the solvent is an organic solvent and / or an inorganic solvent; more preferably, the solvent is one or more of water, methanol and ethanol.

[0028] Preferably, step 1) includes a step of first contacting the catalyst support with a solution containing PVP, acetylacetone and the solvent; more preferably, step 1) includes a step of immersing the catalyst support in a solution containing PVP, acetylacetone and the solvent.

[0029] Preferably, in step 1), the amount of PVP used is 0.05-10 g relative to 100 g of the carrier; more preferably, the amount of PVP used is 0.075-7.5 g relative to 100 g of the carrier.

[0030] Preferably, the amount of acetylacetone used is 0.01-0.5 g relative to 100 g of the carrier; more preferably, the amount of acetylacetone used is 0.03-0.15 g relative to 100 g of the carrier.

[0031] Preferably, the weight ratio of the PVP to the acetylacetone is 1:0.002-1.

[0032] Preferably, the amount of the solvent used is 20-100 mL relative to 100 g of the carrier; more preferably, the amount of the solvent used is 20-70 mL relative to 100 g of the carrier.

[0033] Preferably, in step 1), the first contacting time is 10-60 min; more preferably, the first contacting time is 20-30 min.

[0034] Preferably, the method further comprises: after the first contact, performing a first drying treatment on the modified support; more preferably, the conditions for the first drying treatment include: a first drying temperature of 50-120°C, and a first drying time of 4-20 hours; further preferably, the conditions for the first drying treatment include: a first drying temperature of 60-100°C, and a first drying time of 6-10 hours.

[0035] Preferably, in step 2), the second contacting is performed so that the content of the first active component in the prepared catalyst, calculated as oxide, is 0.023-0.058 wt %; more preferably, the second contacting is performed so that the content of the first active component in the prepared catalyst, calculated as oxide, is 0.023-0.046 wt %.

[0036] Preferably, the second contacting is performed so that the content of the second active component in the prepared catalyst, calculated as oxide, is 0.046-0.172 wt %; more preferably, the second contacting is performed so that the content of the second active component in the prepared catalyst, calculated as oxide, is 0.060-0.110 wt %.

[0037] Preferably, the second contacting is performed so that the content of the promoter in the prepared catalyst calculated as oxide is 0.010-0.035 wt%.

[0038] Preferably, in step 2), the second contacting time is 10-60 min; more preferably, the second contacting time is 20-30 min.

[0039] Preferably, the method further comprises: after the second contact, performing a second drying treatment on the second contact product; more preferably, the conditions for the second drying treatment include: a second drying temperature of 100-200°C, and a second drying time of 10-60 minutes; further preferably, the conditions for the second drying treatment include: a second drying temperature of 120-160°C, and a second drying time of 30-50 minutes.

[0040] Preferably, in step 3), the calcination conditions include: a calcination temperature of 300-600° C., and a calcination time of 2-6 hours; more preferably, the calcination conditions include: a calcination temperature of 400-500° C., and a calcination time of 3-5 hours.

[0041] The third aspect of the present invention provides use of the C2 selective hydrogenation catalyst described in the first aspect of the present invention or the C2 selective hydrogenation catalyst prepared by the method described in the second aspect of the present invention in the hydrogenation of acetylene to produce ethylene.

[0042] Through the above technical solution, after the catalyst support is modified with PVP and acetylacetone, the active components and additives can be firmly fixed on the surface of the support during the subsequent impregnation process without entering the interior of the support pores, so that all active components and additives (if any) can be achieved through only one-step impregnation, and at the same time, the activity and selectivity of the prepared carbon two selective hydrogenation catalyst can be significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a picture of catalyst C1 under a scanning transmission electron microscope. DETAILED DESCRIPTION

[0044] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0045] A first aspect of the present invention provides a C2 selective hydrogenation catalyst, comprising a carrier and a first active component and a second active component supported on the carrier, wherein the first active component is Pd, the second active component comprises Ag, and the spacing between the (111) crystal planes of the first active component Pd in ​​the C2 selective hydrogenation catalyst is 0.228-0.231 nm, and the content of the first active component is 0.023-0.058 wt%, and the content of the second active component is 0.046-0.172 wt%, calculated as oxide.

[0046] In the present invention, preferably, the spacing of the (111) crystal planes of the first active component Pd in ​​the C2 selective hydrogenation catalyst is 0.228-0.230 nm. It can be seen from the (111) crystal plane spacing of the first active component Pd in ​​the C2 selective hydrogenation catalyst that the second active component in the C2 selective hydrogenation catalyst of the present invention enters the crystal lattice of the first active component.

[0047] According to the present invention, the support for the C2 selective hydrogenation catalyst can be any of various supports commonly used in the art for preparing selective hydrogenation catalysts. For example, the support can be one or more of Al2O3, SiO2, MgO, TiO2, molecular sieves, and activated carbon. Preferably, the support is Al2O3. When Al2O3 is used as a support for the catalyst of the present invention, it can synergize with PVP, acetylacetone, and the active components and additives described below to produce a C2 selective hydrogenation catalyst with excellent specific surface area, pore volume, and catalytic performance.

[0048] In the present invention, the active components of the catalyst may include a first active component and a second active component. To improve the acetylene conversion rate of the C2 selective hydrogenation catalyst, the first active component is Pd, and the second active component contains at least Ag. The content of the first active component, calculated as oxide, is 0.023-0.058% by weight, and the content of the second active component is 0.046-0.172% by weight. Thus, through the synergistic effect of Pd and Ag, the catalyst's hydrogenation selectivity can be significantly improved while maintaining a high acetylene conversion rate.

[0049] In addition, in order to further improve the selectivity of the catalyst, preferably, the second active component also contains Au and / or Cu.

[0050] The combination of the first active component and the second active component can be, for example, a combination of Pd and Ag, a combination of Pd, Ag and Au, a combination of Pd, Ag and Cu, and a combination of Pd, Ag, Au and Cu.

[0051] In addition to the first active component and the second active component, the catalyst may further contain a promoter. More preferably, the promoter is Bi and / or Ga. The addition of Bi and / or Ga can further enhance the selectivity of the C2 selective hydrogenation catalyst.

[0052] In addition, according to the present invention, in order to further ensure the catalytic performance of the catalyst, preferably, calculated as oxide, the content of the first active component in the hydrorefining catalyst is 0.023-0.046 wt%, and the content of the second active component in the hydrorefining catalyst is 0.060-0.110 wt%.

[0053] Furthermore, when the C2-selective hydrogenation catalyst further contains a promoter, the promoter content, calculated as oxide, may be 0.010-0.035 wt %. Preferably, the promoter content, calculated as oxide, is 0.015-0.025 wt %. By controlling the promoter content within the aforementioned range, the promoter can further achieve a better synergistic effect with the first active component and the second active component, thereby further improving the hydrogenation selectivity of the catalyst.

[0054] The second aspect of the present invention provides a method for preparing the C2 selective hydrogenation catalyst according to the first aspect of the present invention, wherein the method comprises the following steps:

[0055] 1) in the presence of a solvent, bringing PVP and acetylacetone into first contact with a catalyst support to obtain a modified support having the surface of the catalyst support covered with PVP and acetylacetone;

[0056] 2) contacting the modified support obtained in step 1) with a solution containing the first active component and the second active component to obtain a second contact product;

[0057] 3) calcining the second contact product obtained in step 2);

[0058] Wherein, the first active component is Pd, and the second active component contains Ag.

[0059] First, the preparation steps of the modified carrier of the present invention, the surface of which is at least partially covered with PVP and acetylacetone, are described in detail.

[0060] In the present invention, the molecular weight of the PVP is not particularly limited, as long as it can be coated on the surface of the catalyst support in the presence of a solvent. To ensure that it has a suitable viscosity in the solvent, the molecular weight of the PVP is preferably 10W or less; more preferably, the molecular weight of the PVP is 0.8W-5W.

[0061] In the present invention, the solvent in step 1) is not particularly limited and can be any conventional solvent in the art capable of dissolving PVP and dispersing acetylacetone. For example, the solvent can be an organic solvent and / or an inorganic solvent.

[0062] As the inorganic solvent, water is preferred.

[0063] The organic solvent may be selected from one or more of alcohol solvents, ester solvents, ether solvents and ketone solvents. Preferably, the organic solvent is an alcohol solvent.

[0064] Preferably, the solvent is one or more of water, methanol and ethanol; more preferably, the solvent is water.

[0065] In the present invention, the catalyst carrier may be the same as the catalyst carrier described in the first aspect of the present invention, and will not be described in detail here.

[0066] According to the preparation method of the present invention, in step 1), the amounts of PVP and acetylacetone used can vary within a wide range, as long as the surface of the catalyst support obtained after the first contact is at least partially covered with PVP and acetylacetone. In order to improve the catalytic performance of the prepared selective hydrogenation catalyst, preferably, the amounts of PVP and acetylacetone used are such that the surface of the catalyst support obtained after the first contact is completely covered with PVP and acetylacetone.

[0067] In order to ensure the coverage area of ​​PVP and acetylacetone on the surface of the carrier, preferably, relative to 100g of the carrier, the amount of PVP is 0.05-10g, and the amount of acetylacetone is 0.01-0.5g; more preferably, relative to 100g of the carrier, the amount of PVP is 0.075-7.5g, and the amount of acetylacetone is 0.03-0.15g.

[0068] In addition, in order to further improve the modification effect on the carrier and enhance the catalytic activity of the prepared catalyst, preferably, the weight ratio of the PVP to the acetylacetone is 1:0.002-1; more preferably, 1:0.004-0.4.

[0069] By limiting the amounts of the PVP, acetylacetone and carrier to the above ranges, the uniform distribution of the surface active components and additives of the subsequently prepared catalyst can be ensured, thereby further improving the activity and selectivity of the catalyst.

[0070] Furthermore, the amount of the solvent used relative to the carrier can vary within a wide range and is not particularly limited. However, to ensure the effectiveness of the first contact, the amount of the solvent used is preferably 20-100 mL per 100 g of the carrier; more preferably, the amount of the solvent used is 20-70 mL per 100 g of the carrier.

[0071] According to the present invention, the method for the first contacting is not particularly limited and can be performed according to conventional methods in the art. For example, PVP, acetylacetone, and the solvent can be first mixed to prepare a solution containing PVP and acetylacetone, and then the carrier can be placed in the solution for the first contacting. Alternatively, the PVP, acetylacetone, and the carrier can be placed simultaneously in the solvent for the first contacting. Alternatively, the carrier can be first placed in the solvent, and then the PVP and acetylacetone can be added thereto. Alternatively, acetylacetone can be first mixed with the solvent, and then the PVP and carrier can be added thereto.

[0072] In the present invention, in order to improve the coverage effect of PVP and acetylacetone on the support surface, preferably, step 1) includes a step of first contacting a solution containing PVP, acetylacetone and the solvent with the catalyst support; more preferably, step 1) includes a step of immersing the catalyst support in a solution containing PVP, acetylacetone and the solvent.

[0073] Furthermore, the impregnation is preferably equal volume impregnation.

[0074] In the present invention, there is no particular restriction on the conditions of the first contact. In order to improve the effect of the first contact, the surface of the catalyst carrier is completely covered with PVP and acetylacetone. Preferably, the time of the first contact is 10-60 minutes; more preferably, the time of the first contact is 20-30 minutes.

[0075] In the present invention, in order to make the PVP and acetylacetone more firmly cover the surface of the carrier, preferably, after the first contact is completed, the modified carrier is subjected to a first drying treatment.

[0076] The conditions for the first drying treatment may include: a first drying temperature of 50-120°C and a first drying time of 4-20 hours; preferably, the conditions for the first drying treatment include: a first drying temperature of 60-100°C and a first drying time of 6-10 hours. Thus, a modified catalyst support having a surface covered with PVP and acetylacetone can be obtained.

[0077] Next, the steps of preparing a C2 selective hydrogenation catalyst by co-impregnation using the modified support prepared by the above method are described in detail.

[0078] According to the present invention, the modified support obtained in step 1) is brought into second contact with a solution containing the first active component and the second active component to obtain a second contact product.

[0079] That is, in the present invention, the active components of the catalyst may include a first active component and a second active component, and in order to improve the acetylene conversion rate of the selective hydrogenation catalyst, in the present invention, the first active component is Pd, and the second active component contains at least Ag. Through the synergistic effect of Pd and Ag, the hydrogenation selectivity of the catalyst can be greatly improved while ensuring a high acetylene conversion rate.

[0080] In addition, in order to further improve the selectivity of the catalyst, preferably, the second active component also contains Au and / or Cu.

[0081] The combination of the first active component and the second active component can be, for example, a combination of Pd and Ag, a combination of Pd, Ag and Au, a combination of Pd, Ag and Cu, and a combination of Pd, Ag, Au and Cu.

[0082] In addition, in addition to the first active component and the second active component, an auxiliary agent may be further used. That is, the solution in step 2) may further contain an auxiliary agent.

[0083] Here, the auxiliary agent can be selected in the same manner as in the first aspect of the present invention, and will not be described in detail here.

[0084] According to the present invention, in order to ensure the performance of the prepared catalyst, preferably, the second contacting makes the content of the first active component in the prepared C2 selective hydrogenation catalyst calculated as oxide be 0.023-0.058 weight%; more preferably, the second contacting makes the content of the first active component in the prepared C2 selective hydrogenation catalyst calculated as oxide be 0.023-0.046 weight%.

[0085] In addition, preferably, the second contacting is such that the content of the second active component in terms of oxide in the prepared C2 selective hydrogenation catalyst is 0.046-0.172 wt%; more preferably, the second contacting is such that the content of the second active component in terms of oxide in the prepared C2 selective hydrogenation catalyst is 0.060-0.110 wt%.

[0086] In addition, when the solution in step 2) further contains an auxiliary agent, preferably, the second contacting is such that the content of the auxiliary agent in the prepared C2 selective hydrogenation catalyst, calculated as oxide, is 0.010-0.035 wt %; more preferably, the second contacting is such that the content of the auxiliary agent in the prepared C2 selective hydrogenation catalyst, calculated as oxide, is 0.015-0.025 wt %.

[0087] In the present invention, the conditions for the second contact are not particularly limited. For example, the second contact time can be 10-60 minutes, preferably 20-30 minutes. This ensures the content of the active component and the auxiliary agent (if present) in the prepared catalyst, thereby ensuring the catalytic ability of the catalyst.

[0088] The second contacting method is preferably equal volume immersion.

[0089] In addition, according to the present invention, the method further comprises: after the second contacting, performing a second drying treatment on the second contact product.

[0090] Preferably, the conditions of the second drying treatment include: a second drying temperature of 100-200°C, and a second drying time of 10-60 minutes; more preferably, the conditions of the second drying treatment include: a second drying temperature of 120-160°C, and a second drying time of 30-50 minutes.

[0091] Next, the second contact product after the second drying process is subjected to a calcination process.

[0092] The conditions for the calcination treatment are not particularly limited and can be conventionally selected in the art. For example, the conditions for the calcination treatment may include: a calcination temperature of 300-600°C and a calcination time of 2-6 hours; preferably, the conditions for the calcination treatment include: a calcination temperature of 400-500°C and a calcination time of 3-5 hours.

[0093] The third aspect of the present invention provides the use of the C2 selective hydrogenation catalyst described in the first aspect of the present invention or the C2 selective hydrogenation catalyst prepared by the method described in the second aspect of the present invention in selectively hydrogenating acetylene to produce ethylene in an acetylene-ethylene system.

[0094] The present invention will be described in detail below through examples.

[0095] In the following examples and comparative examples, unless otherwise specified, all raw materials used are conventional commercial products or prepared by conventional methods.

[0096] In the following examples and comparative examples, the metal content in the catalyst was measured by ICP emission spectroscopy.

[0097] In the following examples and comparative examples, the (111) interplanar spacing of the first active component Pd was measured using a scanning transmission electron microscope.

[0098] PVP1 has a molecular weight of 10,000 and was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with analytical purity;

[0099] PVP2 has a molecular weight of 58,000 and was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with analytical purity;

[0100] The molecular weight of PVP3 is 8000 and it was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. with analytical purity.

[0101] Example 1

[0102] 1) Dissolve 0.075 g of PVP1 in 43 mL of deionized water, then add 0.03 g of acetylacetone and stir until dissolved to obtain a first impregnation solution;

[0103] 2) In a coating machine, 43 mL of the first impregnation solution was evenly sprayed onto 100 g of an Al2O3 carrier, and the carrier was rotated and impregnated in the coating machine for 20 minutes, followed by drying at 60°C for 10 hours to obtain a modified carrier;

[0104] 3) Add 0.0650 g of palladium nitrate (analytical grade, excluding water of crystallization, the same below) and 0.1336 g of silver nitrate (analytical grade, the same below) to 47 mL of deionized water and stir to fully dissolve the palladium nitrate and silver nitrate to obtain a second impregnation solution;

[0105] 4) In a coating machine, 47 mL of the impregnation solution obtained in step 3) was evenly sprayed onto 100 g of the modified support obtained in step 1), and the mixture was rotary impregnated in the coating machine for 30 min, dried at 120° C. for 50 min, and then calcined in a muffle furnace at 400° C. for 5 h to prepare Catalyst C1.

[0106] In the obtained catalyst C1, the Pd content, calculated as oxide, was 0.035 wt %, and the Ag content was 0.091 wt %.

[0107] The image of catalyst C1 under scanning transmission electron microscope is as follows: Figure 1 Indicated by Figure 1 It can be seen that the spacing between the (111) crystal planes of the first active component Pd in ​​catalyst C1 is 0.228 nm.

[0108] Example 2

[0109] 1) Dissolve 7.5 g of PVP1 in 50 mL of deionized water, then add 0.03 g of acetylacetone and stir until dissolved to obtain a first impregnation solution;

[0110] 2) In a coating machine, 50 mL of the first impregnation solution was evenly sprayed onto 100 g of an Al2O3 carrier, and the carrier was rotated and impregnated in the coating machine for 10 minutes, followed by drying at 80°C for 8 hours to obtain a modified carrier;

[0111] 3) Add 0.1000 g of palladium nitrate and 0.2200 g of silver nitrate to 50 mL of deionized water and stir thoroughly to dissolve to obtain a second impregnation solution;

[0112] 4) In a coating machine, 50 mL of the impregnation solution obtained in step 3) was evenly sprayed on 100 g of the modified support obtained in step 2), and the mixture was rotated and impregnated in the coating machine for 15 min, dried at 150° C. for 40 min, and then calcined in a muffle furnace at 450° C. for 4 h to prepare Catalyst C2.

[0113] In the obtained catalyst C2, the Pd content, calculated as oxide, was 0.053% by weight, and the Ag content was 0.150% by weight.

[0114] From the image of catalyst C2 under a scanning transmission electron microscope, it can be seen that the spacing between the (111) crystal planes of the first active component Pd in ​​catalyst C2 is 0.230 nm.

[0115] Example 3

[0116] 1) Dissolve 0.3750 g of PVP1 in 48 mL of deionized water, then add 0.15 g of acetylacetone and stir until dissolved to obtain a first impregnation solution;

[0117] 2) In a coating machine, 48 mL of the first impregnation solution was evenly sprayed onto 100 g of an Al2O3 carrier, and the carrier was rotated and impregnated in the coating machine for 30 minutes, followed by drying at 100°C for 6 hours to obtain a modified carrier;

[0118] 3) Add 0.0430 g of palladium nitrate and 0.0793 g of silver nitrate to 40 mL of deionized water and stir thoroughly to dissolve to obtain a second impregnation solution;

[0119] 4) In a coating machine, 40 mL of the impregnation solution obtained in step 3) was evenly sprayed on 100 g of the modified support obtained in step 1), and the mixture was rotated and impregnated in the coating machine for 20 min, dried at 160° C. for 30 min, and then calcined in a muffle furnace at 500° C. for 3 h to prepare Catalyst C3.

[0120] In the obtained catalyst C3, the Pd content, calculated as oxide, was 0.023% by weight, and the Ag content was 0.054% by weight.

[0121] From the image of the catalyst C3 under a scanning transmission electron microscope, it can be seen that the spacing between the 111 crystal planes of the first active component Pd in ​​the catalyst C3 is 0.229 nm.

[0122] Example 4

[0123] The method described in Example 1 was followed, except that

[0124] In step 1), the amount of PVP1 in the first impregnation solution is 0.05 g, and the amount of acetylacetone is 0.01 g;

[0125] Catalyst C4 was prepared.

[0126] In the obtained catalyst C4, the Pd content, calculated as oxide, was 0.035 wt%, and the Ag content was 0.091 wt%.

[0127] From the image of catalyst C4 under a scanning transmission electron microscope, it can be seen that the spacing between the (111) crystal planes of the first active component Pd in ​​catalyst C4 is 0.230 nm.

[0128] Example 5

[0129] The method described in Example 1 was followed, except that

[0130] In step 1), the amount of PVP1 in the first impregnation solution is 10 g, and the amount of acetylacetone is 0.2 g;

[0131] Catalyst C5 was prepared.

[0132] In the obtained catalyst C5, the Pd content, calculated as oxide, was 0.035% by weight, and the Ag content was 0.091% by weight.

[0133] From the image of catalyst C5 under a scanning transmission electron microscope, it can be seen that the spacing between the (111) crystal planes of the first active component Pd in ​​catalyst C5 is 0.230 nm.

[0134] Example 6

[0135] The method described in Example 1 was followed, except that

[0136] In step 3), the second impregnation liquid is prepared by:

[0137] 0.0650 g of palladium nitrate, 0.0958 g of silver nitrate, and 0.0958 g of chloroauric acid were added to 47 mL of deionized water, and stirred thoroughly to dissolve the palladium nitrate, silver nitrate, and chloroauric acid to obtain a second impregnation solution.

[0138] Catalyst C6 was prepared.

[0139] In the obtained catalyst C6, the content of Pd, calculated as oxide, was 0.035 wt%, the content of Ag was 0.065 wt%, and the content of Au was 0.062 wt%.

[0140] From the image of catalyst C6 under a scanning transmission electron microscope, it can be seen that the spacing between the (111) crystal planes of the first active component Pd in ​​catalyst C6 is 0.230 nm.

[0141] Example 7

[0142] The method described in Example 1 was followed, except that

[0143] In step 3), the second impregnation liquid is prepared by:

[0144] 0.0650 g of palladium nitrate, 0.0719 g of silver nitrate, 0.0341 g of copper nitrate trihydrate, and 0.0479 g of chloroauric acid were added to 47 mL of deionized water and stirred thoroughly to dissolve the palladium nitrate, silver nitrate, copper nitrate, and chloroauric acid to obtain a second impregnation solution.

[0145] Catalyst C7 was prepared.

[0146] In the obtained catalyst C7, the content of Pd, calculated as oxide, was 0.035 wt%, the content of Ag was 0.049 wt%, the content of Cu was 0.011 wt%, and the content of Au was 0.031 wt%.

[0147] From the image of the catalyst C7 under a scanning transmission electron microscope, it can be seen that the spacing between the 111 crystal planes of the first active component Pd in ​​the catalyst C7 is 0.230 nm.

[0148] Example 8

[0149] The method described in Example 1 was followed, except that

[0150] In step 3), the second impregnation liquid is prepared by:

[0151] 0.0650 g of palladium nitrate, 0.1198 g of silver nitrate, and 0.0734 g of gallium nitrate were added to 47 mL of deionized water and stirred thoroughly to dissolve the palladium nitrate, silver nitrate, and gallium nitrate to obtain a second impregnation solution.

[0152] Catalyst C8 was prepared.

[0153] In the obtained catalyst C8, the content of Pd, calculated as oxides, was 0.035 wt%, the content of Ag was 0.082 wt%, and the content of Ga was 0.027 wt%.

[0154] From the image of catalyst C8 under a scanning transmission electron microscope, it can be seen that the spacing between the (111) crystal planes of the first active component Pd in ​​catalyst C8 is 0.229 nm.

[0155] Example 9

[0156] Catalyst C9 was prepared by following the method described in Example 1, except that PVP1 was replaced by PVP2.

[0157] In the obtained catalyst C9, the Pd content, calculated as oxide, was 0.035% by weight, and the Ag content was 0.091% by weight.

[0158] From the image of catalyst C9 under a scanning transmission electron microscope, it can be seen that the spacing between the (111) crystal planes of the first active component Pd in ​​catalyst C9 is 0.229 nm.

[0159] Example 10

[0160] Catalyst C10 was prepared according to the method described in Example 1, except that PVP1 was replaced by PVP3.

[0161] In the obtained catalyst C10, the Pd content, calculated as oxide, was 0.035% by weight, and the Ag content was 0.091% by weight.

[0162] From the image of the catalyst C10 under a scanning transmission electron microscope, it can be seen that the spacing between the 111 crystal planes of the first active component Pd in ​​the catalyst C10 is 0.229 nm.

[0163] Comparative Example 1

[0164] The method described in Example 1 was followed, except that

[0165] The catalyst support is not subjected to the modification treatments of steps 1) and 2), that is, the second impregnation liquid is directly sprayed onto the support.

[0166] Catalyst D1 was prepared.

[0167] In the obtained catalyst D1, the Pd content, calculated as oxide, was 0.035 wt %, and the Ag content was 0.091 wt %.

[0168] From the image of catalyst D1 under a scanning transmission electron microscope, it can be seen that the spacing between the (111) crystal planes of the first active component Pd in ​​catalyst D1 is 0.225 nm.

[0169] Test Example 1

[0170] Catalytic performance test of C1-C10 and D1

[0171] The prepared catalysts C1-C10 and D1 were reduced with hydrogen. The reduction method was as follows: the catalysts were loaded into a reactor, the reactor temperature was raised to 180°C, and then hydrogen was introduced into the reactor to reduce the catalysts for 3-6 hours. The reactor was then cooled to room temperature and the introduction of hydrogen was stopped.

[0172] The activity of the catalyst was evaluated in a fixed-bed microreactor. The specific method was as follows:

[0173] 0.5 g of catalyst was loaded into a stainless steel reactor with a volume of , and after nitrogen displacement, the reaction raw materials were introduced into the reactor for acetylene selective hydrogenation reaction. The reaction conditions included: reaction temperature of 55 ° C, reaction pressure of 1.0 MPa, volume space velocity of 9000 h -1 .

[0174] The composition of the reaction raw materials is as follows:

[0175] Ethylene 92.907 volume% Acetylene 0.428 volume% Ethane 5.950 volume% hydrogen 0.715 volume%

[0176] The acetylene content, ethylene content and ethane content in the reactor outlet material were measured by gas chromatography.

[0177] Calculate the acetylene conversion C (%) and ethylene selectivity S (%).

[0178] Among them, the acetylene content in the raw gas is expressed as C r ≡ The acetylene content in the product is expressed as C p ≡ Indicates the content of ethylene in the raw material by C r ＝ The ethylene content in the product is expressed as C p ＝ Indicates the content of ethane in the raw material by C r - The ethane content in the product is expressed as C p - express.

[0179] Since the molecular weights of ethylene, acetylene and ethane are similar and their influencing factors are extremely close under the same conditions, the integrated area is used to represent their respective contents.

[0180] C / %=[(C r ≡ -C p ≡ ) / C r ≡ ]×100%

[0181] S / %={(C p ＝ -C r＝ ) / [(C p ＝ -C r ＝ )+(C p - -C r - )]}×100%

[0182] The test results are shown in Table 1.

[0183] Table 1

[0184] Catalyst No. Acetylene conversion rate C (%) Ethylene selectivity S (%) C1 98.50 64.50 C2 98.55 62.22 C3 98.43 63.15 C4 95.20 55.45 C5 94.78 56.57 C6 99.24 68.50 C7 99.35 65.31 C8 99.18 66.80 C9 94.38 56.89 C10 97.29 63.66 D1 80.20 53.20

[0185] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A C2 selective hydrogenation catalyst comprising a carrier and a first active component and a second active component supported on the carrier, wherein the first active component is Pd, the second active component contains Ag, and in the C2 selective hydrogenation catalyst, the spacing between the (111) crystal planes of the first active component Pd is 0.228-0.231 nm; in, Calculated as oxide, the content of the first active component is 0.023-0.058 wt%, and the content of the second active component is 0.046-0.172 wt%. The preparation method of the C2 selective hydrogenation catalyst comprises the following steps: 1) in the presence of a solvent, bringing PVP and acetylacetone into first contact with a catalyst support to obtain a modified support having a surface of the catalyst support at least partially covered with PVP and acetylacetone; 2) contacting the modified support obtained in step 1) with a solution containing the first active component and the second active component to obtain a second contact product; 3) calcining the second contact product obtained in step 2); In step 1), relative to 100g of the carrier, the amount of PVP used is 0.05-10g, and the amount of acetylacetone used is 0.01-0.5g. In step 3), the calcination conditions include: a calcination temperature of 300-600° C. and a calcination time of 2-6 hours.

2. The C2 selective hydrogenation catalyst according to claim 1, wherein The spacing between the (111) crystal planes of the first active component Pd is 0.228-0.230 nm.

3. The C2 selective hydrogenation catalyst according to claim 1, wherein The carrier is one or more of Al2O3, SiO2, MgO, TiO2, molecular sieve and activated carbon.

4. The C2 selective hydrogenation catalyst according to claim 3, wherein The carrier is Al2O3.

5. The C2 selective hydrogenation catalyst according to any one of claims 1 to 4, wherein Calculated as oxide, the content of the first active component in the C2 selective hydrogenation catalyst is 0.023-0.046 wt %.

6. The C2 selective hydrogenation catalyst according to any one of claims 1 to 4, wherein The second active component further contains Au and / or Cu; Calculated as oxide, the content of the second active component in the C2 selective hydrogenation catalyst is 0.060-0.110 wt%.

7. The C2 selective hydrogenation catalyst according to any one of claims 1 to 4, wherein The C2 selective hydrogenation catalyst further contains a promoter; The auxiliary agent is Bi and / or Ga; Calculated as oxide, the content of the auxiliary agent in the C2 selective hydrogenation catalyst is 0.010-0.035 wt%.

8. The method for preparing the C2 selective hydrogenation catalyst according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: 1) in the presence of a solvent, bringing PVP and acetylacetone into first contact with a catalyst support to obtain a modified support having a surface of the catalyst support at least partially covered with PVP and acetylacetone; 2) contacting the modified support obtained in step 1) with a solution containing the first active component and the second active component to obtain a second contact product; 3) calcining the second contact product obtained in step 2); Wherein, the first active component is Pd, the second active component contains Ag, In step 1), relative to 100g of the carrier, the amount of PVP used is 0.05-10g, and the amount of acetylacetone used is 0.01-0.5g. In step 3), the calcination conditions include: a calcination temperature of 300-600° C. and a calcination time of 2-6 hours.

9. The preparation method according to claim 8, wherein In step 1), the molecular weight of the PVP is less than 10W.

10. The preparation method according to claim 9, wherein The molecular weight of the PVP is 0.8W-5W.

11. The preparation method according to claim 8, wherein In step 2), the second active component further contains Au and / or Cu.

12. The preparation method according to claim 8, wherein Step 2) the solution further contains an auxiliary agent; The auxiliary agent is Bi and / or Ga.

13. The preparation method according to claim 8, wherein The carrier is one or more of Al2O3, SiO2, MgO, TiO2, molecular sieve and activated carbon.

14. The preparation method according to claim 13, wherein The carrier is Al2O3.

15. The preparation method according to any one of claims 8 to 14, wherein: In step 1), the solvent is an organic solvent and / or an inorganic solvent; Step 1) includes a step of bringing a solution containing PVP, acetylacetone and the solvent into first contact with the catalyst support.

16. The preparation method according to claim 15, wherein In step 1), the solvent is one or more of water, methanol and ethanol; Step 1) includes the step of impregnating the catalyst support in a solution containing PVP, acetylacetone and the solvent.

17. The preparation method according to any one of claims 8 to 14, wherein: In step 1), relative to 100 g of the carrier, the amount of PVP used is 0.075-7.5 g, and the amount of acetylacetone used is 0.03-0.15 g.

18. The preparation method according to any one of claims 8 to 14, wherein: The weight ratio of the PVP to the acetylacetone is 1:0.002-1.

19. The preparation method according to any one of claims 8 to 14, wherein: Relative to 100g of the carrier, the amount of the solvent is 20-100mL; In step 1), the first contact time is 10-60 minutes; The method further comprises: after the first contacting, performing a first drying treatment on the modified support; The conditions of the first drying treatment include: a first drying temperature of 50-120° C., and a first drying time of 4-20 hours.

20. The preparation method according to claim 19, wherein The amount of the solvent used is 20-70 mL relative to 100 g of the carrier; The first contact time is 20-30 minutes; The conditions of the first drying treatment include: a first drying temperature of 60-100° C., and a first drying time of 6-10 hours.

21. The preparation method according to any one of claims 8 to 14, wherein: In step 2), the second contacting is performed so that the content of the first active component in the prepared catalyst is 0.023-0.058% by weight, calculated as oxide; The second contacting is performed so that the content of the second active component in the prepared catalyst, calculated as oxide, is 0.046-0.172 wt %.

22. The preparation method according to claim 21, wherein In step 2), the second contacting is performed so that the content of the first active component in the prepared catalyst is 0.023-0.046% by weight, calculated as oxide; The second contacting is performed so that the content of the second active component in the prepared catalyst, calculated as oxide, is 0.060-0.110 wt %.

23. The preparation method according to claim 12, wherein The second contacting is performed so that the content of the promoter in the prepared catalyst, calculated as oxide, is 0.010-0.035 wt %.

24. The preparation method according to any one of claims 8 to 14, wherein: In step 2), the second contact time is 10-60 minutes; The method further includes: after the second contacting, performing a second drying process on the second contact product; The conditions of the second drying treatment include: a second drying temperature of 100-200° C., and a second drying time of 10-60 minutes.

25. The preparation method according to claim 24, wherein The second contact time is 20-30 minutes; The conditions of the second drying treatment include: a second drying temperature of 120-160° C., a second drying time of 30-50 min; The calcination conditions include: a calcination temperature of 400-500° C. and a calcination time of 3-5 hours.

26. Use of the C2 selective hydrogenation catalyst according to any one of claims 1 to 7 or the C2 selective hydrogenation catalyst prepared by the method according to any one of claims 8 to 25 in the hydrogenation of acetylene to produce ethylene.

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