An ethylene oxide catalyst and a method for preparing the same

Abstract

The present application relates to a kind of ethylene oxide catalyst and its preparation method, catalyst preparation technical field, the preparation method of the ethylene oxide catalyst includes the following steps: obtaining alumina carrier;Obtain the impregnation solution of silver active component, alkali metal auxiliary agent and rare earth metal auxiliary agent;Using double-cone impregnation method, the impregnation solution is loaded on the alumina carrier, and catalyst intermediate is obtained;Using vibration activation mode, the catalyst intermediate is activated, and the ethylene oxide catalyst is obtained.The present application uses double-cone impregnation method and vibration activation mode, and they cooperate with each other, significantly improve the performance of existing ethylene oxide catalyst, overcome the deficiency of existing ethylene oxide catalyst using capacity excess impregnation method and muffle furnace / tube furnace activation.

Description

Technical Field

[0001] The present invention relates to the technical field of catalyst preparation, and in particular to an ethylene oxide catalyst and a preparation method thereof. Background Art

[0002] Ethylene oxide (EO), the simplest cyclic ether, is a crucial product in the ethylene industry. Its unique cyclic structure enables the production of a wide range of fine chemicals, including ethylene glycol, synthetic detergents, nonionic surfactants, antifreeze agents, emulsifiers, and glycol ethers. It is also used in the production of plasticizers, lubricants, rubber, and plastics. EO is widely used in numerous fields, including laundry, electronics, pharmaceuticals, pesticides, textiles, papermaking, automotive, and oil extraction and refining.

[0003] As the primary catalyst for the production of ethylene oxide by ethylene oxidation, ethylene oxide catalysts have garnered significant research attention. Using highly active, selective, and stable catalysts is crucial for achieving economic success in this process. However, current research focuses on catalyst supports and catalyst composition, neglecting the impact of catalyst impregnation and activation processes. The performance of ethylene oxide catalysts is not only closely related to support properties and catalyst composition, but also to the control of catalyst preparation and activation processes.

[0004] The key steps in preparing ethylene oxide catalysts are impregnation with a silver solution and catalyst activation. The impregnation process typically utilizes excess volume impregnation. Because solution diffusion during the impregnation process can affect the final catalyst performance, the equipment used is crucial. However, currently used common impregnation methods severely impact catalyst performance. Furthermore, catalyst activation is crucial for determining the catalyst's ultimate performance, with the rate of solution evaporation during activation determining the catalyst's performance. Existing muffle furnace and tubular furnace activation methods limit the catalyst's ultimate performance. Summary of the Invention

[0005] To solve the above problems, the present invention provides an ethylene oxide catalyst and a preparation method thereof.

[0006] In a first aspect, the present invention provides a method for preparing an ethylene oxide catalyst, the method comprising the following steps:

[0007] Obtaining an alumina support;

[0008] obtaining an impregnation solution containing a silver active component, an alkali metal additive, and a rare earth metal additive;

[0009] The impregnation liquid is loaded onto the alumina support by a double cone impregnation method to obtain a catalyst intermediate;

[0010] The catalyst intermediate is activated by vibration activation to obtain the ethylene oxide catalyst.

[0011] Furthermore, the physical and chemical properties of the alumina carrier include: a specific surface area of ​​1 to 2 m 2 / g, α-Al2O3 carrier with a porosity of 45% to 75%, an Al2O3 weight content greater than 98%, a strength of 60 to 200 N / particle, and a shape of Raschig rings, five-hole columns, or seven-hole columns. The preferred specific surface area is 0.8 to 1.5 m 2 / g, porosity 50-55%, strength 80-120N / particle, and an α-Al2O3 carrier in the shape of a five-hole column.

[0012] Furthermore, based on the total weight of the ethylene oxide catalyst, the weight content of each component in the ethylene oxide catalyst is: the weight content of the silver active component is 12 to 25 wt%, the content of the alkali metal additive is 100 to 1000 ppm, and the weight content of the rare earth metal additive is 100 to 1200 ppm.

[0013] Furthermore, the step of loading the impregnation liquid onto the alumina support by a double cone impregnation method to obtain a catalyst intermediate includes the following process:

[0014] The alumina carrier is added to a double cone device, and vacuum is applied, with the vacuum degree controlled at -0.05 to -0.25 MPa. Cooling water is circulated through the double cone to maintain the temperature at -10 to 30°C, and pretreatment is performed for 1 to 3 hours. Subsequently, the vacuum is turned off, the impregnation liquid is added, the double cone speed is 1 to 5 rpm, and the double cone is pressurized to 1 to 3 MPa with nitrogen, and the pressure is maintained for 1 to 5 hours to obtain the catalyst intermediate.

[0015] Furthermore, the step of activating the catalyst intermediate by vibration activation to obtain the ethylene oxide catalyst includes the following process:

[0016] The catalyst intermediate is added into a vibration activation furnace, and the vacuum frequency is controlled at 20-20 Hz, the catalyst intermediate contact temperature is 120-280° C., the hot air flow rate is 10-50 L / h, and the activation time is 1-50 min to obtain the ethylene oxide catalyst.

[0017] Furthermore, the silver active component includes silver nitrate.

[0018] Furthermore, the alkali metal additive includes at least one of Li, Na, K, Rb, and Cs.

[0019] Furthermore, the rare earth metal additive includes at least one of La, Ce, Eu, and Y.

[0020] In a second aspect, the present invention provides an ethylene oxide catalyst, which is prepared by the preparation method described in any one of the first aspects.

[0021] The above technical solution provided by the embodiment of the present invention has at least the following advantages compared with the prior art:

[0022] The present invention provides an ethylene oxide catalyst and a preparation method thereof. The present invention adopts a double-cone impregnation method and a vibration activation method, which cooperate with each other to significantly improve the performance of existing ethylene oxide catalysts and overcome the shortcomings of existing ethylene oxide catalysts that use excess capacity impregnation methods and muffle furnace / tube furnace activation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 This is a flow chart of a method for preparing an ethylene oxide catalyst provided in an embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of the double cone impregnation process in the method for preparing the ethylene oxide catalyst provided in an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of the vibration activation process in the preparation method of the ethylene oxide catalyst provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0029] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0030] In a first aspect, the present invention provides a method for preparing an ethylene oxide catalyst, such as Figure 1 As shown, the preparation method of the ethylene oxide catalyst comprises the following steps:

[0031] Obtaining an alumina support;

[0032] obtaining an impregnation solution containing a silver active component, an alkali metal additive, and a rare earth metal additive;

[0033] The impregnation liquid is loaded onto the alumina support by a double cone impregnation method to obtain a catalyst intermediate;

[0034] The catalyst intermediate is activated by vibration activation to obtain the ethylene oxide catalyst.

[0035] The present invention provides an ethylene oxide catalyst and a preparation method thereof. The present invention adopts a double-cone impregnation method and a vibration activation method, which cooperate with each other to significantly improve the performance of existing ethylene oxide catalysts and overcome the shortcomings of existing ethylene oxide catalysts that use excess capacity impregnation methods and muffle furnace / tube furnace activation.

[0036] In some specific embodiments, the physical and chemical properties of the alumina support include: a specific surface area of ​​1 to 2 m 2 / g, an α-Al2O3 carrier with a porosity of 45% to 75%, an Al2O3 weight content greater than 98%, a strength of 60 to 200N / particle, and a shape of Raschig rings, five-hole columns, and seven-hole columns.

[0037] In some specific embodiments, based on the total weight of the ethylene oxide catalyst, the weight content of each component in the ethylene oxide catalyst is: the weight content of the silver active component is 12 to 25 wt%, preferably 15 to 18 wt%; the content of the alkali metal additive is 100 to 1000 ppm, preferably 300 to 600 ppm; the weight content of the rare earth metal additive is 100 to 1200 ppm, preferably 400 to 800 ppm.

[0038] In some specific embodiments, Figure 2 As shown, the step of loading the impregnation liquid onto the alumina support by a double cone impregnation method to obtain a catalyst intermediate includes the following process:

[0039] The alumina carrier is added to a double cone device, and vacuum is applied, with the vacuum degree controlled at -0.05 to -0.25 MPa. Cooling water is circulated through the double cone to maintain the temperature at -10 to 30°C, and pretreatment is performed for 1 to 3 hours. Subsequently, the vacuum is turned off, the impregnation liquid is added, the double cone speed is 1 to 5 rpm, and the double cone is pressurized to 1 to 3 MPa with nitrogen, and the pressure is maintained for 1 to 5 hours to obtain the catalyst intermediate.

[0040] In some specific embodiments, Figure 3 As shown, the step of activating the catalyst intermediate by vibration activation to obtain the ethylene oxide catalyst includes the following process:

[0041] The catalyst intermediate is added into a vibration activation furnace, and the vacuum frequency is controlled at 20-20 Hz, the catalyst intermediate contact temperature is 120-280° C., the hot air flow rate is 10-50 L / h, and the activation time is 1-50 min to obtain the ethylene oxide catalyst.

[0042] In some embodiments, the silver active component includes silver nitrate.

[0043] In some specific embodiments, the alkali metal additive includes at least one of Li, Na, K, Rb, and Cs.

[0044] In some specific embodiments, the rare earth metal additive includes at least one of La, Ce, Eu, and Y.

[0045] It should be noted that the components and raw materials involved in the ethylene oxide catalyst provided in the embodiments of the present invention can be directly commercially available products unless otherwise specified or specified.

[0046] In a second aspect, based on a general inventive concept, the present invention provides an ethylene oxide catalyst, which is prepared by the preparation method described in any one of the first aspects.

[0047] The ethylene oxide catalyst provided by the present invention is gray-black in color, and the average crushing strength of the catalyst should be greater than 80N / particle.

[0048] The present invention provides a method for evaluating the above-mentioned ethylene oxide catalyst, comprising:

[0049] The present invention uses a laboratory-customized micro-evaluation device for evaluation. The inner diameter of the reaction tube is 1.8 cm. The prepared catalyst is ground into 60-100 mesh particles. The catalyst loading mass is 2 g. Inert porcelain balls are pressed (cushioned) on the top (bottom) to ensure that the catalyst is not carried away during the reaction. The catalyst loading position is placed in the constant temperature zone of the reactor.

[0050] The evaluation conditions were reaction pressure 2.0 MPa, reaction temperature 220°C, and space velocity 4200 h -1 The raw gas composition is: 28% ethylene, 7% oxygen, 2% carbon dioxide, and the balance is nitrogen as a stabilizing gas.

[0051] The present invention will be further described below in conjunction with specific examples. It should be understood that these examples are intended to illustrate the present invention only and are not intended to limit the scope of the invention. The experimental methods in the following examples where specific conditions are not specified are generally measured in accordance with national standards. If there are no corresponding national standards, then the methods are carried out in accordance with general international standards, conventional conditions, or the conditions recommended by the manufacturer.

[0052] Example 1

[0053] This example provides an ethylene oxide catalyst, the preparation method of which comprises the following steps:

[0054] Support Preparation: 1000 g of gibbsite and 200 g of pseudogibbsite were kneaded in a kneader. 200 mL of a 20% aqueous nitric acid solution, 2 g of SiO₂, and 10 g of NH₄F were added, and the mixture was kneaded for 20 minutes. The mixture was then extruded into a mesoporous cylinder using an extruder, dried at 100°C for 3 hours, and calcined at 1350°C for 4 hours to obtain Support A.

[0055] Preparation of impregnation solution: Accurately weigh 800 g of silver oxalate and dissolve it in 30 L of water and ethylenediamine solution. Then add 8 g of ammonium rhenate and 15 g of cesium sulfate to the solution; stir and let it stand for 1 hour before use.

[0056] Impregnation process: A 2.5L impregnation bicone was used, and 500g of the homemade α-Al2O3 carrier was added to the reactor. The carrier was then pretreated at -0.1MPa with circulating cooling water at 15°C for 2 hours. The vacuum was then turned off, and the impregnation solution was added. The temperature inside the bicone was maintained at 15°C. The bicone was rotated at 2 rpm, and the reactor was pressurized to 2MPa with nitrogen and maintained for 2 hours.

[0057] Activation process: Add the above catalyst into a vibration activation furnace, ensure the temperature is 180°C, the hot air flow rate is 30L / h, and the activation time is 5 minutes, which is recorded as catalyst C1.

[0058] Example 2

[0059] This example provides an ethylene oxide catalyst, the preparation method of which comprises the following steps:

[0060] Carrier preparation and impregnation solution configuration reference example 1

[0061] Impregnation process: A 2.5L impregnation bicone was used, and 500g of the homemade α-Al2O3 carrier was added to the reactor. The carrier was then pretreated at -0.1MPa with circulating cooling water at 15°C for 2 hours. The vacuum was then turned off, and the impregnation solution was added. The temperature inside the bicone was maintained at 15°C. The bicone was rotated at 2 rpm, and the reactor was pressurized to 2MPa with nitrogen and maintained for 2 hours.

[0062] Activation process: Add the above catalyst into a vibration activation furnace, ensure the temperature is 200°C, the hot air flow rate is 30L / h, and the activation time is 5 minutes. It is recorded as catalyst C2.

[0063] Example 3

[0064] This example provides an ethylene oxide catalyst, the preparation method of which comprises the following steps:

[0065] Carrier preparation and impregnation solution configuration reference example 1

[0066] Impregnation process: A 2.5L impregnation bicone was used, and 500g of the homemade α-Al2O3 carrier was added to the reactor. The carrier was then pretreated at -0.1MPa with circulating cooling water at 15°C for 2 hours. The vacuum was then turned off, and the impregnation solution was added. The temperature inside the bicone was maintained at 15°C. The bicone was rotated at 2 rpm, and the reactor was pressurized to 2MPa with nitrogen and maintained for 2 hours.

[0067] Activation process: Add the above catalyst into a vibration activation furnace, ensure the temperature is 220°C, the hot air flow rate is 30L / h, and the activation time is 5 minutes. It is recorded as catalyst C3.

[0068] Example 4

[0069] This example provides an ethylene oxide catalyst, the preparation method of which comprises the following steps:

[0070] Carrier preparation and impregnation solution configuration reference example 1

[0071] Impregnation process: A 2.5L impregnation bicone was used, and 500g of the homemade α-Al2O3 carrier was added to the reactor. The carrier was then pretreated at -0.1MPa with circulating cooling water at 15°C for 2 hours. The vacuum was then turned off, and the impregnation solution was added. The temperature inside the bicone was maintained at 15°C. The bicone was rotated at 2 rpm, and the reactor was pressurized to 2MPa with nitrogen and maintained for 2 hours.

[0072] Activation process: Add the above catalyst into a vibration activation furnace, ensure the temperature is 240°C, the hot air flow rate is 30L / h, and the activation time is 5 minutes. It is recorded as catalyst C4.

[0073] Comparative Example 1

[0074] This example provides an ethylene oxide catalyst, the preparation method of which comprises the following steps:

[0075] Carrier preparation and impregnation solution configuration reference example 1

[0076] Impregnation process: Add 500g of homemade α-Al2O3 carrier into the reaction tank, add impregnation liquid, and impregnate for 2h.

[0077] Activation process: Add the above catalyst into a vibration activation furnace, ensure the temperature is 220°C, the hot air flow rate is 30L / h, and the activation time is 5 minutes, which is recorded as catalyst D1.

[0078] Comparative Example 2

[0079] This example provides an ethylene oxide catalyst, the preparation method of which comprises the following steps:

[0080] Carrier preparation and impregnation solution configuration reference example 1

[0081] Impregnation process: A rotary evaporator was selected as the catalyst preparation reactor, 500 g of the homemade α-Al2O3 carrier was added to the reactor, and then the carrier was ensured to be at -0.1 MPa, and the impregnation liquid was added and impregnated for 2 h.

[0082] Activation process: Add the above catalyst into a vibration activation furnace, ensure the temperature is 220°C, the hot air flow rate is 30L / h, and the activation time is 5min, which is recorded as catalyst D2.

[0083] Comparative Example 3

[0084] This example provides an ethylene oxide catalyst, the preparation method of which comprises the following steps:

[0085] Carrier preparation and impregnation solution configuration reference example 1

[0086] Impregnation process: A 2.5L impregnation bicone was used, and 500g of the homemade α-Al2O3 carrier was added to the reactor. The carrier was then pretreated at -0.1MPa with circulating cooling water at 15°C for 2 hours. The vacuum was then turned off, and the impregnation solution was added. The temperature inside the bicone was maintained at 15°C. The bicone was rotated at 2 rpm, and the reactor was pressurized to 2MPa with nitrogen and maintained for 2 hours.

[0087] Activation process: Add the above catalyst into the tubular activation, ensure the temperature is 220℃, and the activation time is 5 minutes, which is recorded as catalyst D3.

[0088] Comparative Example 4

[0089] This example provides an ethylene oxide catalyst, the preparation method of which comprises the following steps:

[0090] Carrier preparation and impregnation solution configuration reference example 1

[0091] Impregnation process: A 2.5L impregnation bicone was used, and 500g of the homemade α-Al2O3 carrier was added to the reactor. The carrier was then pretreated at -0.1MPa with circulating cooling water at 15°C for 2 hours. The vacuum was then turned off, and the impregnation solution was added. The temperature inside the bicone was maintained at 15°C. The bicone was rotated at 2 rpm, and the reactor was pressurized to 2MPa with nitrogen and maintained for 2 hours.

[0092] Activation process: Add the above catalyst into a muffle furnace, ensure the temperature is 220°C, and activate for 5 minutes, which is recorded as catalyst D4.

[0093] Test Case

[0094] This example uses a laboratory-customized micro-evaluation device for evaluation. The inner diameter of the reaction tube is 1.8 cm. The prepared catalyst is ground into 60-100 mesh particles. The catalyst loading mass is 2 g. Inert ceramic balls are placed on the top (bottom) to ensure that the catalyst is not carried away during the reaction. The catalyst loading position is placed in the constant temperature zone of the reactor.

[0095] The evaluation conditions were reaction pressure 2.0 MPa, reaction temperature 220°C, and space velocity 4200 h -1 The raw gas composition is: 28% ethylene, 7% oxygen, 2% carbon dioxide, and the balance is nitrogen as a stabilizing gas.

[0096] The physical properties of the catalyst are shown in Table 1, and the catalyst performance test results are shown in Table 2.

[0097] Table 1 Catalyst physical properties

[0098] catalyst Strength (N) <![CDATA[Al2O3(%)]]> <![CDATA[Ag2O(%)]]> Cs (ppm) Re (ppm) Catalyst C1 102 83.98 16.02 503 601 Catalyst C2 102 83.95 16.05 504 609 Catalyst C3 103 83.97 16.03 508 603 Catalyst C4 102 83.99 16.01 501 606 Catalyst D1 105 83.96 16.04 504 604 Catalyst D2 103 83.98 16.02 503 607 Catalyst D3 102 83.99 16.01 505 603 Catalyst D4 101 83.96 16.04 506 601

[0099] Table 2 Catalyst evaluation table

[0100]

[0101]

[0102] As shown in Tables 1 and 2 above: 1) The catalyst activated in Example 3 using a double-cone impregnation method and a vibration activation furnace exhibits superior performance; 2) The results of Example 3 and Comparative Example 1 demonstrate that the catalyst prepared using a negative pressure and pressurized impregnation method performs better than the catalyst prepared without the negative pressure and pressurized steps. The results of Example 3 and Comparative Example 2 demonstrate that the catalyst prepared using only negative pressure impregnation performs worse than the catalyst prepared using both negative pressure and pressurized impregnation methods; 3) The results of Example 3, Comparative Examples 3, and Comparative Examples 4 demonstrate that the catalyst activated using a vibration activation furnace outperforms catalysts activated using a tubular furnace or muffle furnace.

[0103] Various embodiments of the present invention may be presented in the form of a range; it should be understood that the description in a range format is only for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention; therefore, the range description should be considered to have specifically disclosed all possible subranges and single numerical values ​​within the range. For example, the description of a range from 1 to 6 should be considered to have specifically disclosed subranges 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., as well as single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. In addition, whenever a numerical range is indicated herein, it is intended to include any cited numeral (fractional or integer) within the indicated range.

[0104] In the present invention, unless otherwise specified, the directional words used, such as "upper" and "lower", specifically refer to the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. mean "including but not limited to". In this article, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. Wherein A and B can be singular or plural. In this article, "at least one" means one or more, and "plurality" means two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple, respectively.

[0105] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for preparing an ethylene oxide catalyst, characterized in that: The preparation method of the ethylene oxide catalyst comprises the following steps: Support preparation: 1000 g of gibbsite and 200 g of pseudogibbsite were kneaded in a kneader, 200 mL of a 20% aqueous nitric acid solution, 2 g of SiO2, and 10 g of NH4F were added, and the mixture was kneaded for 20 min. The mixture was then extruded into a mesoporous cylinder using an extruder, dried at 100°C for 3 hours, and calcined at 1350°C for 4 hours to obtain Support A. Preparation of impregnation solution: Accurately weigh 800g of silver oxalate and dissolve it in 30L of water and ethylenediamine solution. Then add 8g of ammonium rhenate and 15g of cesium sulfate to the solution; stir and let it stand for 1h before use; Impregnation process: 2.5L of an impregnation double cone was selected, and 500g of the carrier A was added to the reactor. The carrier A was then pretreated at -0.1MPa with cooling water circulating through the double cone at 15°C for 2 hours. The vacuum was then turned off, and the impregnation liquid was added. The temperature inside the reaction double cone was maintained at 15°C, the double cone rotation speed was 2 rpm, and the reactor was pressurized to 2MPa with nitrogen and maintained at this pressure for 2 hours. Activation process: The above catalyst was added into a vibration activation furnace, the temperature was maintained at 220° C., the hot air flow rate was 30 L / h, and the activation time was 5 min to obtain the ethylene oxide catalyst.

2. An ethylene oxide catalyst, characterized in that The ethylene oxide catalyst is prepared by the preparation method according to claim 1.

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