Ethylene oxide catalyst without chlorine injection in use process as well as preparation method and application of ethylene oxide catalyst

Abstract

The invention discloses an ethylene oxide catalyst without chlorine injection in the use process and a preparation method and application thereof, and relates to the technical field of ethylene oxide catalysts, the preparation method comprises the following steps: obtaining an alpha-Al2O3 carrier; a silver source, a nickel source and a reducing agent are added into a solvent to be mixed, and impregnation liquid is obtained; the alpha-Al2O3 carrier is added into the impregnation liquid for impregnation, and a catalyst precursor is obtained; and reducing the catalyst precursor to obtain the ethylene oxide catalyst. By adding iron, cobalt, nickel and other transition metals, the selectivity of the silver catalyst can be effectively improved, a stabilizing effect similar to chlorination is achieved, the ethylene oxide catalyst which does not need chlorine injection in the using process is prepared, and the defects in the prior art are effectively overcome.

Description

Technical Field

[0001] The present invention relates to the technical field of ethylene oxide catalysts, and particularly to an ethylene oxide catalyst that does not require chlorine injection during use, and its preparation method and application. Background Art

[0002] Ethylene oxide (EO) is an important basic chemical globally and is widely used in the production of high-value-added products such as ethylene glycol, surfactants, pharmaceuticals, and plastics, with a market scale exceeding $40 billion. Currently, the industrial production of EO mainly uses the ethylene oxidation method, that is, under the action of a silver-based catalyst, ethylene and oxygen are selectively oxidized under the conditions of 200 - 300 °C and 1 - 3 MPa. However, this reaction is an exothermic reaction with many side reactions during the process, and it is necessary to precisely control the reaction conditions to improve the selectivity of EO and reduce the formation of by-products such as carbon dioxide.

[0003] Traditional EO catalysts adopt a structure of silver supported on an α-aluminum oxide carrier and are optimized for their selectivity and stability through chlorination treatment. The chlorination process usually involves adding chlorides (such as vinyl chloride or organic chlorides) to the reaction system to form surface silver chloride (AgCl) species, which can inhibit the sintering of silver particles and improve the anti-loss performance of the catalyst. However, this chlorination method has multiple challenges: environmental and safety risks: the toxicity of chlorine poses a threat to the health of workers and the environment and increases the safety protection cost. Equipment corrosion: chlorine and its derivatives will accelerate the corrosion of reaction equipment, resulting in a shortened equipment life and increased maintenance cost. Increased production complexity: the chlorination process may affect the formation of by-products, increase the difficulty of EO purification, and increase the production cost.

[0004] Therefore, the development of an efficient silver-based catalyst without chlorination has become an important direction in the research of EO catalysts. Summary of the Invention

[0005] To solve the above problems, the present invention provides an ethylene oxide catalyst that does not require chlorine injection during use, and its preparation method and application.

[0006] In the first aspect, the present invention provides a preparation method of an ethylene oxide catalyst that does not require chlorine injection during use, as Figure 1 shown, the preparation method includes the following steps:

[0007] Obtain an α-Al2O3 carrier;

[0008] Add a silver source, a nickel source, and a reducing agent to a solvent for mixing to obtain an impregnation solution;

[0009] Add the α-Al2O3 carrier to the impregnation solution for impregnation to obtain a catalyst precursor;

[0010] Reduce the catalyst precursor to obtain the ethylene oxide catalyst.

[0011] Further, the step of obtaining the α-Al2O3 support includes the following process:

[0012] Knead boehmite and pseudo-boehmite in a kneader, then add aqueous nitric acid solution, SiO2 and NH4F and continue kneading; extrude the obtained mixture into mesoporous cylinders in an extruder, and then perform drying and calcination to obtain the α-Al2O3 support.

[0013] Further, the weight ratio of the boehmite, the pseudo-boehmite, the SiO2 and the NH4F is 1000:200:4:20; based on g / ml, the weight-to-volume ratio of the boehmite and the aqueous nitric acid solution is 1000:200, and the weight percentage of the aqueous nitric acid solution is 30 wt%.

[0014] Further, the working condition parameters of the drying include: temperature is 115°C to 125°C, time is 3 to 5 hours; the working condition parameters of the calcination include: temperature is 1500°C to 1600°C, time is 7 to 10 hours.

[0015] Further, by weight percentage, the Ag content in the ethylene oxide catalyst is 5 to 15%; by weight percentage, the Ni content in the ethylene oxide catalyst is 0.1 to 0.5%.

[0016] Further, by weight percentage, the Ag content in the ethylene oxide catalyst is 8 to 12%; by weight percentage, the Ni content in the ethylene oxide catalyst is 0.2 to 0.35%.

[0017] Further, the reducing agent includes at least one of ethylene glycol, hydrazine hydrate, glucose and formaldehyde; the working condition parameters of the reduction include: temperature is 50 to 300°C, time is 1 to 30 min, and the reducing atmosphere is nitrogen.

[0018] Further, the working condition parameters of the reduction include: temperature is 100 to 200°C, time is 5 to 20 min, and the reducing atmosphere is nitrogen.

[0019] In a second aspect, based on the same inventive concept, the present invention provides an ethylene oxide catalyst that does not require chlorine injection during use, and the ethylene oxide catalyst is prepared by using the preparation method of the ethylene oxide catalyst that does not require chlorine injection according to any one of the first aspect.

[0020] In a third aspect, based on the same inventive concept, the present invention provides an application of an ethylene oxide catalyst that does not require chlorine injection during use, prepared by the preparation method of the ethylene oxide catalyst that does not require chlorine injection according to any one of the second aspects, in the preparation of ethylene oxide by the ethylene oxidation method, and does not require chlorine injection during use.

[0021] The above technical solutions provided by the embodiments of the present invention have at least the following advantages compared with the prior art:

[0022] The embodiments of the present invention provide an ethylene oxide catalyst that does not require chlorine injection during use, its preparation method and application. By adding transition metals such as iron, cobalt, and nickel, the present invention can effectively improve the selectivity of the silver catalyst and play a stabilizing role similar to chlorination, and obtain an ethylene oxide catalyst that does not require chlorine injection during use, effectively making up for the deficiencies of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings herein are incorporated into the specification and form a part of the specification, showing embodiments consistent with the present invention and used together with the specification to explain the principles of the present invention.

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 It is a schematic flow chart of a preparation method of an ethylene oxide catalyst that does not require chlorine injection during use provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0027] Unless otherwise specifically stated, various raw materials, reagents, instruments, and equipment used in the present invention can be obtained through market purchases or can be prepared by existing methods.

[0028] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. The experimental methods without specific conditions in the following embodiments are usually determined according to national standards. If there is no corresponding national standard, they are carried out according to general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0029] Example 1

[0030] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0031] Support preparation: Knead 1000 g of boehmite and 200 g of pseudo-boehmite in a kneader, add 200 mL of 30 wt% nitric acid aqueous solution, as well as 4 g of SiO2 and 20 g of NH4F, and knead for 20 min. Extrude mesoporous cylinders in an extruder, dry at 120 °C for 4 hours, and calcine at 1550 °C for 8 hours to obtain the support.

[0032] Impregnating solution preparation: Accurately weigh 51.16 g of silver nitrate and 3.41 g of nickel nitrate, dissolve them in a solution of 250 mL of water, ethylenediamine, ethanolamine, and formaldehyde (water:ethylenediamine:ethanolamine:formaldehyde = 5:3:1:1), continue to stir in a cold water bath solution for 30 min, and then let it stand for 1 h for standby.

[0033] Impregnation process: Select an impregnation double cone (2.5 L), add 500 g of self-made α-Al2O3 support to the reactor, and then ensure that the support is pretreated at -0.1 MPa and 15 °C with circulating cooling water in the double cone for 2 h. Subsequently, close the vacuum, add the impregnating solution, and ensure that the system temperature inside the reaction double cone is 15 °C. The rotation speed of the double cone is 2 revolutions / min, pressurize the reactor with nitrogen to 2 MPa, and keep the pressure for 2 h. To remove the excess liquid, put the impregnated catalyst precursor into a centrifuge, centrifuge at a speed of 3000 r / min, take it out after centrifuging for 3 min, and perform reduction.

[0034] Reduction process: Use a tubular furnace for reduction, the temperature is 120 °C, and the reduction atmosphere is nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, slowly cool the catalyst. Denote it as catalyst C1.

[0035] Example 2

[0036] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0037] Support preparation: Refer to Example 1

[0038] Preparation of impregnation solution: Weigh accurately 66.90 g of silver nitrate and 3.72 g of nickel nitrate, dissolve them in a solution of 250 mL of water, ethylenediamine, ethanolamine, and formaldehyde (water:ethylenediamine:ethanolamine:formaldehyde = 5:3:1:1), continue stirring in a cold water bath solution for 30 min, and then let it stand for 1 h for standby.

[0039] Impregnation process: Select an impregnation double cone (2.5 L), add 500 g of self-made α-Al2O3 support to the reactor, then ensure that the support is pretreated at -0.1 MPa and with circulating cooling water in the double cone at 15 °C for 2 h. Subsequently, turn off the vacuum, add the impregnation solution, and ensure that the system temperature inside the reaction double cone is 15 °C. The rotation speed of the double cone is 2 revolutions / min, pressurize the reactor to 2 MPa with nitrogen, and hold the pressure for 2 h. To remove the excess liquid, put the impregnated catalyst precursor into a centrifuge for centrifugation, the rotation speed of the centrifuge: 3000 r / min, take it out after centrifugation for 3 min, and carry out reduction.

[0040] Reduction process: Use a tubular furnace for reduction, the temperature is: 120 °C, and the reduction atmosphere is nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, slowly cool the catalyst. Denote it as catalyst C2.

[0041] Example 3

[0042] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0043] Support preparation: Please refer to Example 1

[0044] Preparation of impregnation solution: Weigh accurately 82.64 g of silver nitrate and 4.34 g of nickel nitrate, dissolve them in a solution of 250 mL of water, ethylenediamine, ethanolamine, and formaldehyde (water:ethylenediamine:ethanolamine:formaldehyde = 5:3:1:1), continue stirring in a cold water bath solution for 30 min, and then let it stand for 1 h for standby.

[0045] Impregnation process: Select an impregnation double cone (2.5 L), add 500 g of self-made α-Al2O3 support to the reactor, then ensure that the support is pretreated at -0.1 MPa and with circulating cooling water in the double cone at 15 °C for 2 h. Subsequently, turn off the vacuum, add the impregnation solution, and ensure that the system temperature inside the reaction double cone is 15 °C. The rotation speed of the double cone is 2 revolutions / min, pressurize the reactor to 2 MPa with nitrogen, and hold the pressure for 2 h. To remove the excess liquid, put the impregnated catalyst precursor into a centrifuge for centrifugation, the rotation speed of the centrifuge: 3000 r / min, take it out after centrifugation for 3 min, and carry out reduction.

[0046] Reduction process: Reduction is carried out using a tube furnace at a temperature of 120°C, and the reduction atmosphere is nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, the catalyst is slowly cooled. It is denoted as catalyst C3.

[0047] Example 4

[0048] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0049] Support preparation: Refer to Example 1.

[0050] Impregnating solution preparation: Accurately weigh 98.38 g of silver nitrate and 4.96 g of nickel nitrate, dissolve them in a solution of 250 mL of water and ethylenediamine, ethanolamine, and formaldehyde (water:ethylenediamine:ethanolamine:formaldehyde = 5:3:1:1), continue stirring in a cold water bath solution for 30 min, and then let it stand for 1 h for standby.

[0051] Impregnation process: Select an impregnation double cone (2.5 L), add 500 g of self-made α-Al2O3 support to the reactor, then ensure that the support is pretreated at -0.1 MPa and 15°C with circulating cooling water in the double cone for 2 h. Subsequently, close the vacuum, add the impregnating solution, and ensure that the system temperature inside the reaction double cone is 15°C. The rotation speed of the double cone is 2 revolutions / min, pressurize the reactor to 2 MPa with nitrogen, and maintain the pressure for 2 h. To remove the excess liquid, put the impregnated catalyst precursor into a centrifuge, the rotation speed of the centrifuge is 3000 r / min, take it out after centrifuging for 3 min, and carry out reduction.

[0052] Reduction process: Reduction is carried out using a tube furnace at a temperature of 120°C, and the reduction atmosphere is nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, the catalyst is slowly cooled. It is denoted as catalyst C4.

[0053] Example 5

[0054] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0055] Support preparation: Refer to Example 1.

[0056] Impregnating solution preparation: Accurately weigh 82.64 g of silver nitrate and 4.34 g of nickel nitrate, dissolve them in a solution of 250 mL of water and ethylenediamine, ethanolamine, and ethylene glycol (water:ethylenediamine:ethanolamine:ethylene glycol = 5:3:1:1), continue stirring in a cold water bath solution for 30 min, and then let it stand for 1 h for standby.

[0057] Impregnation process: Select an impregnation double cone (2.5 L), add 500 g of self-made α-Al2O3 support to the reactor, and then pre-treat the support at -0.1 MPa with circulating cooling water in the double cone at 15 °C for 2 h. Subsequently, close the vacuum, add the impregnation solution, and ensure that the system temperature inside the reaction double cone is 15 °C. The rotation speed of the double cone is 2 revolutions / min, pressurize the reactor with nitrogen to 2 MPa, and maintain the pressure for 2 h. To remove the excess liquid, centrifuge the impregnated catalyst precursor in a centrifuge at a speed of 3000 r / min, take it out after centrifuging for 3 min, and perform reduction.

[0058] Reduction process: Use a tubular furnace for reduction at a temperature of 120 °C and a reduction atmosphere of nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, slowly cool the catalyst. Denote it as catalyst C5.

[0059] Example 6

[0060] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0061] Support preparation: See Example 1.

[0062] Impregnation solution preparation: Accurately weigh 82.64 g of silver nitrate and 4.34 g of nickel nitrate, dissolve them in a solution of 250 mL of water and ethylenediamine, ethanolamine, and formaldehyde (water:ethylenediamine:ethanolamine:hydrazine hydrate = 5:3:1:1), continue to stir in a cold water bath solution for 30 min, let it stand for 1 h, and set aside.

[0063] Impregnation process: Select an impregnation double cone (2.5 L), add 500 g of self-made α-Al2O3 support to the reactor, and then pre-treat the support at -0.1 MPa with circulating cooling water in the double cone at 15 °C for 2 h. Subsequently, close the vacuum, add the impregnation solution, and ensure that the system temperature inside the reaction double cone is 15 °C. The rotation speed of the double cone is 2 revolutions / min, pressurize the reactor with nitrogen to 2 MPa, and maintain the pressure for 2 h. To remove the excess liquid, centrifuge the impregnated catalyst precursor in a centrifuge at a speed of 3000 r / min, take it out after centrifuging for 3 min, and perform reduction.

[0064] Reduction process: Use a tubular furnace for reduction at a temperature of 120 °C and a reduction atmosphere of nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, slowly cool the catalyst. Denote it as catalyst C6.

[0065] Example 7

[0066] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0067] Support preparation: See Example 1.

[0068] Preparation of impregnation solution: Accurately weigh 82.64 g of silver nitrate and 4.34 g of cobalt nitrate, dissolve them in a solution of 250 mL of water and ethylenediamine, ethanolamine, and formaldehyde (water:ethylenediamine:ethanolamine:formaldehyde = 5:3:1:1), continue stirring in a cold water bath solution for 30 min, let it stand for 1 h after stirring, and set aside for use.

[0069] Impregnation process: Select an impregnation double cone (2.5 L), add 500 g of self-made α-Al2O3 support to the reactor, then ensure that the support is pretreated at -0.1 MPa and with circulating cooling water in the double cone at 15 °C for 2 h. Subsequently, turn off the vacuum, add the impregnation solution, and ensure that the system temperature inside the reaction double cone is 15 °C. The rotation speed of the double cone is 2 revolutions / min, pressurize the reactor with nitrogen to 2 MPa, and keep the pressure for 2 h. To remove the excess liquid, put the impregnated catalyst precursor into a centrifuge for centrifugation, the rotation speed of the centrifuge: 3000 r / min, take it out after centrifugation for 3 min, and carry out reduction.

[0070] Reduction process: Use a tubular furnace for reduction, the temperature is: 120 °C, and the reduction atmosphere is nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, slowly cool the catalyst. Record it as catalyst C7.

[0071] Example 8

[0072] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0073] Support preparation: Please refer to Example 1

[0074] Preparation of impregnation solution: Accurately weigh 82.64 g of silver nitrate and 4.41 g of iron nitrate, dissolve them in a solution of 250 mL of water and ethylenediamine, ethanolamine, and formaldehyde (water:ethylenediamine:ethanolamine:formaldehyde = 5:3:1:1), continue stirring in a cold water bath solution for 30 min, let it stand for 1 h after stirring, and set aside for use.

[0075] Impregnation process: Select an impregnation double cone (2.5 L), add 500 g of self-made α-Al2O3 support to the reactor, then ensure that the support is pretreated at -0.1 MPa and with circulating cooling water in the double cone at 15 °C for 2 h. Subsequently, turn off the vacuum, add the impregnation solution, and ensure that the system temperature inside the reaction double cone is 15 °C. The rotation speed of the double cone is 2 revolutions / min, pressurize the reactor with nitrogen to 2 MPa, and keep the pressure for 2 h. To remove the excess liquid, put the impregnated catalyst precursor into a centrifuge for centrifugation, the rotation speed of the centrifuge: 3000 r / min, take it out after centrifugation for 3 min, and carry out reduction.

[0076] Reduction process: Reduction is carried out using a tubular furnace at a temperature of 120 °C and a reduction atmosphere of nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, the catalyst is slowly cooled. It is denoted as catalyst C8.

[0077] Example 9

[0078] This example provides an ethylene oxide catalyst, and its preparation method includes the following steps:

[0079] Support preparation: Refer to Example 1.

[0080] Impregnating solution preparation: Accurately weigh 82.64 g of silver nitrate and dissolve it in a solution of 250 mL of water, ethylenediamine, ethanolamine, and formaldehyde (water:ethylenediamine:ethanolamine:formaldehyde = 5:3:1:1). Continue stirring in a cold water bath solution for 30 min, then let it stand for 1 h and set aside.

[0081] Impregnation process: Select an impregnation double cone (2.5 L). Add 500 g of the self-made α-Al2O3 support to the reactor. Then, ensure that the support is pretreated at -0.1 MPa and with circulating cooling water at 15 °C in the double cone for 2 h. Subsequently, turn off the vacuum, add the impregnating solution, and ensure that the system temperature inside the reaction double cone is 15 °C. The rotation speed of the double cone is 2 revolutions / min. Pressurize the reactor with nitrogen to 2 MPa and maintain the pressure for 2 h. To remove the excess liquid, place the impregnated catalyst precursor in a centrifuge. The centrifuge speed is 3000 r / min. After centrifuging for 3 min, take it out and carry out reduction.

[0082] Reduction process: Reduction is carried out using a tubular furnace at a temperature of 120 °C and a reduction atmosphere of nitrogen. The nitrogen flow rate is 1 L / h. After the reduction process is completed, the catalyst is slowly cooled. It is denoted as catalyst C9.

[0083] The physical property table of the ethylene oxide catalyst obtained from the above examples is shown in Table 1.

[0084] Table 1

[0085] Catalyst Ag(%) Ni(%) Co(%) Fe(%) Catalyst C1 6.53 0.22 / / Catalyst C2 8.50 0.24 / / Catalyst C3 10.51 0.28 / / Catalyst C4 12.49 0.32 / / Catalyst C5 10.49 0.28 / / Catalyst C6 10.50 0.28 / / Catalyst C7 10.51 / 0.28 / Catalyst C8 10.49 / / 0.28 Catalyst C9 10.50 / / /

[0086] Test example

[0087] In this example, a laboratory micro-evaluation device is used for evaluation. The inner diameter of the reaction tube is 1.8 cm. Grind the prepared catalyst into particles of 60 - 100 mesh. The loading mass of the catalyst is 2 g, and inert porcelain balls are placed on the top (bottom) for pressing (padding) to ensure that the catalyst is not carried away during the reaction. The loading position of the catalyst is placed in the constant temperature zone of the reactor;

[0088] The evaluation conditions are a reaction pressure of 2.0 MPa, a reaction temperature of 220 - 250 °C, and a space velocity of 4200 h -1, The raw material gas composition is: 28% ethylene, 7% oxygen, 2% carbon dioxide, and the balance is nitrogen as a stabilizing gas, the balance.

[0089] The test results of the catalyst performance are shown in Table 2 as follows.

[0090] Table 2

[0091]

[0092]

[0093] As shown in Table 2 above: The results of Examples 1 - 4 show that the catalyst has the best performance under the conditions of a silver content of 10.5% and a nickel content of 0.28%. The results of Examples 3, 5, and 6 show that the reduction effect of the reducing agents is formaldehyde > hydrazine hydrate > glucose. The results of Examples 3, 7, 8, and 9 show the effects of the catalysts: silver-nickel alloy > silver-cobalt alloy > silver-iron alloy > silver.

[0094] The various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and single values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, and this applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0095] The above description is only a specific implementation manner of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features claimed herein.

Claims

1. A preparation method of an ethylene oxide catalyst that does not require chlorine injection during use, characterized in that, The preparation method includes the following steps: Obtain an α-Al2O3 support; Add a silver source, a nickel source, and a reducing agent to a solvent for mixing to obtain an impregnation solution; Add the α-Al2O3 support to the impregnation solution for impregnation to obtain a catalyst precursor; Reduce the catalyst precursor to obtain the ethylene oxide catalyst.

2. The preparation method of the ethylene oxide catalyst that does not require chlorine injection during use according to claim 1, wherein, The step of obtaining the α-Al2O3 support includes the following process: Knead boehmite and pseudo-boehmite in a kneader, then add an aqueous nitric acid solution, SiO2, and NH4F and continue kneading; extrude the obtained mixture into mesoporous cylinders in an extruder, and then perform drying and calcination to obtain the α-Al2O3 support.

3. The preparation method of the ethylene oxide catalyst that does not require chlorine injection during use according to claim 2, characterized in that, The weight ratio of the boehmite, the pseudo-boehmite, the SiO2, and the NH4F is 1000:200:4:20; calculated by g / ml, the weight-to-volume ratio of the boehmite and the aqueous nitric acid solution is 1000:200, and the weight percentage of the aqueous nitric acid solution is 30 wt%.

4. The preparation method of the ethylene oxide catalyst that does not require chlorine injection during use according to claim 2, characterized in that, The working condition parameters of the drying include: temperature is 115°C to 125°C, time is 3 to 5 hours; the working condition parameters of the calcination include: temperature is 1500°C to 1600°C, time is 7 to 10 hours.

5. The preparation method of the ethylene oxide catalyst that does not require chlorine injection during use according to claim 1, characterized in that, Calculated by weight percentage, the Ag content in the ethylene oxide catalyst is 5 to 15%; calculated by weight percentage, the Ni content in the ethylene oxide catalyst is 0.1 to 0.5%.

6. The preparation method of the ethylene oxide catalyst that does not require chlorine injection during use according to claim 1, characterized in that, Calculated by weight percentage, the Ag content in the ethylene oxide catalyst is 8 to 12%; calculated by weight percentage, the Ni content in the ethylene oxide catalyst is 0.2 to 0.35%.

7. The preparation method of the ethylene oxide catalyst that does not require chlorine injection during use according to claim 1, characterized in that, The reducing agent includes at least one of ethylene glycol, hydrazine hydrate, glucose, and formaldehyde; the working condition parameters of the reduction include: temperature is 50 to 300°C, time is 1 to 30 min, and the reducing atmosphere is nitrogen.

8. The preparation method of the ethylene oxide catalyst that does not require chlorine injection during use according to claim 1, characterized in that, The working condition parameters of the reduction include: temperature is 100 to 200°C, time is 5 to 20 min, and the reducing atmosphere is nitrogen.

9. An ethylene oxide catalyst that does not require chlorine injection during use, characterized in that, The ethylene oxide catalyst is prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the ethylene oxide catalyst according to claim 9, which does not require chlorine injection during use, in the preparation of ethylene oxide by ethylene oxidation method, characterized in that, Chlorine injection is not required during use.

Images