Domestication method of ethylene epoxidized silver catalyst

Abstract

The invention discloses a domestication method of an ethylene epoxidized silver catalyst, and belongs to the technical field of domestication of silver catalysts. The method can effectively remove residual organic amine, precursor and other additives in the preparation process of the catalyst, promote the formation and uniform distribution of nanoscale silver particles, stabilize the interaction of active components and auxiliaries, promote the effective active structure on the surface of the carrier to tend to be stable, and improve the performance of the catalyst. Meanwhile, the difference of the catalyst in industrial production is removed, the possibility of local temperature runaway of the device is reduced, and the catalyst runs stably. The operation steps are simple, and the whole domestication steps can be completed in the heating process. The nano silver particle size on the surface of the catalyst can be kept stable, the difference between the same products is reduced, the safety in enterprise production operation is ensured, the time cost is saved, the economic cost is reduced, the method has great significance in industrial application, the enterprise input cost can be reduced, the energy can be reduced, the efficiency can be improved, and the productivity conversion can be quickly realized.

Description

Technical Field

[0001] The invention belongs to the technical field of silver catalyst acclimation, and particularly relates to a method for acclimating an ethylene epoxidation silver catalyst. Background Art

[0002] The epoxidation of ethylene to produce ethylene oxide (EO) is a key reaction in the petrochemical industry, with global annual production exceeding 30 million tons and exceeding $40 billion. Silver catalysts are key to this reaction, and their performance (activity, selectivity, and stability) directly determines production efficiency and economic benefits.

[0003] In recent years, with increasingly stringent environmental protection requirements and rising energy costs, it is necessary not only to develop high-performance silver catalysts, but also to study efficient activation means and methods of catalysts.

[0004] Patent CN104884443 provides a startup method, but can only maintain a low level of selectivity (less than 86%) during each different stage, which cannot meet the needs of most industrial devices.

[0005] Furthermore, patent CN103261178A introduces a gas containing olefins, oxygen, and at least one organic chloride during the catalyst startup phase. This results in a complex startup process with complex gas composition and cumbersome operation. The catalyst activation time is long and highly variable, significantly increasing the operating costs of the device and reducing product profits.

[0006] The prior art CN 118719059 A discloses a method for acclimating an ethylene epoxide silver catalyst. The technical requirements are stringent, the reaction temperature range is too narrow, and the gas composition during the acclimation process is complex, all of which are important factors limiting its industrial production application.

[0007] The existing technology still has many shortcomings, and there is an urgent need to optimize the distribution of surface active components of the catalyst through effective domestication methods to improve the performance and stability of the catalyst. Summary of the Invention

[0008] The present invention aims to provide a method for acclimating an ethylene epoxide silver catalyst. This method effectively removes residual organic amines, precursors, and other additives from the catalyst preparation process, promotes the formation and uniform distribution of nanoscale silver particles, stabilizes the interaction between the active component and the additive, promotes the stabilization of the effective active structure on the support surface, and improves catalyst performance. Furthermore, the method eliminates catalyst variability during industrial production, reduces the possibility of localized overheating in the device, and ensures stable catalyst operation.

[0009] The present invention is achieved through the following technical solutions:

[0010] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0011] S1. Under a pure nitrogen atmosphere, place the ethylene epoxide silver catalyst to be acclimated in the reaction system, increase the temperature at a certain rate, and introduce oxygen until the concentration is stable. Maintain the reaction under this temperature and atmosphere conditions.

[0012] S2, then stop the oxygen supply, and after the oxygen concentration is lower than the primary set concentration, increase the reaction temperature and maintain the reaction under this temperature and atmosphere conditions;

[0013] S3. After the reaction in S2 is completed, the temperature is lowered, the catalyst volume space velocity is increased, and then ethylene is added. When the ethylene concentration reaches above the initial concentration, the oxygen concentration is slowly increased to an intermediate concentration;

[0014] After the ethylene epoxidation reaction occurs, continue to increase the oxygen concentration to the third level and the ethylene concentration to the intermediate level to ensure and maintain the oxygen concentration at the reaction outlet;

[0015] S4, if the ethylene oxide at the outlet of the reaction does not change within the expected time, slowly add chloride to stabilize the ethylene epoxide silver catalyst to be acclimated;

[0016] S5. After the tamed ethylene silver epoxide catalyst is stabilized, the amount of chloride added is reduced to half of the initial concentration. Then, according to the industrial application scenario, the reactant concentration is increased to the target value. Then, the ethylene, oxygen concentration and chloride addition amount are alternately increased in a step-by-step manner to complete the taming.

[0017] Preferably, in S1, the temperature is raised to 150-160°C at a rate of 10-100°C / h;

[0018] The oxygen is introduced until the oxygen mass concentration is stabilized at 1-2%;

[0019] Keep the reaction under the temperature and atmosphere conditions for 4 to 8 hours;

[0020] The volume space velocity of the ethylene epoxide silver catalyst to be acclimated is not less than 2000h -1 .

[0021] Preferably, in S2, the primary set concentration of oxygen is lower than 0.1%;

[0022] Raising the reaction temperature to 240-260° C.;

[0023] The heating rate does not exceed 20-100℃ / h;

[0024] The reaction is maintained at this temperature and atmosphere for 6 to 24 hours.

[0025] Preferably, in S3, the temperature is lowered to 215-240°C; the catalyst volume space velocity is increased to 3000-6000h -1 ;

[0026] When the ethylene concentration reaches an initial concentration of 5% or more, the oxygen concentration is slowly increased to an intermediate concentration of 1%;

[0027] After the ethylene epoxidation reaction occurs, continue to increase the oxygen concentration to the tertiary concentration of 1-3%, and increase the ethylene concentration to the intermediate concentration of 12-15%, ensuring and maintaining the oxygen concentration at the reaction outlet not less than 0.5% and not more than 1%.

[0028] Preferably, in S4, the expected time is 4 hours;

[0029] The chloride is ethyl chloride;

[0030] The concentration of the chloride is 0.5 to 10 ppm.

[0031] Preferably, in S5, the amount of chloride added is 0.3 to 5 ppm.

[0032] Preferably, in S5, the target values ​​of reactant concentrations are: ethylene concentration 30%, oxygen concentration 6.5%.

[0033] Preferably, in said S5, when the concentrations of ethylene and oxygen are alternately increased in a stepwise manner, each increase and adjustment shall not exceed 1% of the concentration;

[0034] The concentration of the chloride is adjusted in the range of 2 to 20 ppm.

[0035] Compared with the prior art, the present invention has at least the following technical effects:

[0036] (1) The present invention provides a method for acclimating an ethylene epoxide silver catalyst. This method effectively removes residual organic amines, precursors, and other additives left during the catalyst preparation process, promotes the formation and uniform distribution of nanoscale silver particles, stabilizes the interaction between the active component and the additive, promotes the stabilization of the effective active structure on the support surface, and improves catalyst performance. Simultaneously, it eliminates catalyst variability during industrial production, reduces the possibility of localized overheating in the device, and ensures stable catalyst operation.

[0037] (2) This acclimation method utilizes the temperature rising process and adds some heat treatment methods at the temperature and time nodes in the steps. After reasonable and process parameter optimization, it can significantly improve the selectivity and activity of the same catalyst.

[0038] Compared with the existing catalyst acclimation method, the acclimation method has simple operation steps and is easy to implement, and the entire acclimation step can be completed during the temperature rising process.

[0039] (3) At the same time, this method can also keep the particle size of nano-scale silver particles on the catalyst surface stable, reduce the differences between the same products, ensure the safety of the company's production operation, save time costs, and reduce economic costs. In industrial applications, it is of great significance. It can reduce the company's investment costs, reduce energy and increase efficiency, quickly realize production capacity conversion, and provide support for enterprises in market competition. DETAILED DESCRIPTION

[0040] The embodiments of the present invention will be described in detail below with reference to the examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. Specific conditions not specified in the examples are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially.

[0041] All concentrations in this technology are mass concentrations.

[0042] The technical solution of a specific embodiment of the present invention is:

[0043] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0044] S1. Place the ethylene epoxide silver catalyst to be acclimated in a reaction system with a pure nitrogen atmosphere, heat it to 160°C at a rate of 10-100°C / h, and then introduce oxygen to stabilize the oxygen concentration at 1-2%. Maintain this temperature and atmosphere for 4-8 hours, with a catalyst volume space velocity of not less than 2000 h -1 .

[0045] The function of this step is to remove amine compounds on the catalyst surface and decompose organic compounds.

[0046] S2. Stop the oxygen supply. When the oxygen concentration is lower than 0.1%, raise the temperature to 240-260°C at a heating rate not exceeding 20-100°C / h. Maintain the temperature and atmosphere for 6-24 hours.

[0047] The purpose of this step is to remove the silver precursor by high-temperature decomposition, so that the nano-silver particles and alkali metals or other metal oxides can work together to form a fixed shape, thereby improving the activity and stability of the catalyst.

[0048] S3. Reduce the temperature to 215-240℃ and increase the airspeed to 3000-6000h -1 .

[0049] Add ethylene. When the ethylene concentration reaches above 5%, slowly increase the oxygen concentration to 1%. Ethylene epoxidation occurs under the action of the catalyst, and the outlet oxygen concentration decreases as ethylene oxide is produced. Increase the oxygen concentration to 1-3% and the ethylene concentration to 12-15%, ensuring the outlet oxygen concentration is no less than 0.5% and no more than 1%, maintaining the oxygen concentration constant.

[0050] After the outlet ethylene oxide concentration remains unchanged for 4 hours, a chloride having an initial concentration of 0.5 to 10 ppm is slowly added. The preferred chloride is ethyl monochloride.

[0051] The purpose of this step is to stabilize the particle size of the catalyst silver particles, increase the service life, and fully activate the catalyst.

[0052] S4. After the catalyst selectivity is stabilized, the amount of chloride added is reduced to half of the initial concentration, i.e. 0.3-5 ppm.

[0053] Then, according to the industrial application scenario method, the reactant concentration can be increased to the target value: ethylene concentration 30% and oxygen concentration 6.5%.

[0054] The concentrations of ethylene and oxygen are increased alternately in a step-by-step manner. Each increase should not exceed 1% concentration. After the adjustment, the amount of chloride added is adjusted accordingly. The concentration range of chloride is 2 to 20 ppm.

[0055] The purpose of this step is to increase the reaction to a high load, so as to observe the catalyst reaction and make reasonable adjustments to the chloride to ensure that the catalyst has stable selectivity and activity.

[0056] Table 1 below shows the corresponding adjustment settings for ethylene and oxygen concentrations when increasing them alternately in a step-by-step manner:

[0057] Table 1 Reaction load ethylene, oxygen, ethyl chloride concentration addition step

[0058] step Ethylene concentration (mol%) Oxygen concentration (mol%) Ethyl chloride concentration (ppm) 1 12 3 0.4 2 13 3.2 3 14 3.4 4 15 3.6 5 16 3.8 0.5 6 17 4 7 18 4.2 8 19 4.5 9 20 4.8 10 21 5 0.6 11 22 5.2 12 23 5.5 13 24 5.6 14 25 5.7 0.7 15 26 5.9 16 27 6.1 17 28 6.3 18 29 6.4 0.8 19 30 6.5

[0059] Example 1:

[0060] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0061] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 3500h -1 , heat to 160°C under nitrogen atmosphere at a heating rate of 40°C / h, introduce oxygen until the concentration reaches 2%, and maintain the temperature for 8h.

[0062] S2. Heating at a rate of 20°C / h to 260°C, stop introducing oxygen, place the catalyst back in a pure nitrogen atmosphere, and maintain the temperature for 6 hours.

[0063] S3, lower the temperature to 225℃ and maintain the airspeed at 3500h -1 After adding ethylene to a concentration of over 5%, slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is above 0.5% and below 1%. The catalyst reaction is stable for 4 hours. Then, 0.8 ppm of ethylene monochloride is added to increase the catalyst selectivity to a stable level.

[0064] S4. After the catalyst selectivity stabilizes, the ethyl chloride concentration is reduced to 0.4 ppm and continuously added. Then, the ethylene and oxygen concentrations are alternately increased in a stepwise manner according to Table 1. The experimental data is recorded as Ag-1.

[0065] Example 2:

[0066] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0067] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 1500h -1 , heat to 160°C under nitrogen atmosphere at a heating rate of 40°C / h, introduce oxygen until the concentration reaches 2%, and maintain the temperature for 8h.

[0068] S2. Heating at a rate of 20°C / h to 260°C, stop introducing oxygen, place the catalyst back in a pure nitrogen atmosphere, and maintain the temperature for 6 hours.

[0069] S3, lower the temperature to 225℃ and maintain the airspeed at 3500h -1 After adding ethylene to a concentration of over 5%, slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is above 0.5% and below 1%. The catalyst reaction is stable for 4 hours. Then, 0.8 ppm of ethylene monochloride is added to increase the catalyst selectivity to a stable level.

[0070] S4. After the catalyst selectivity stabilizes, reduce the concentration of ethylene chloride to 0.4 ppm and continue adding it. Then, increase the concentration of ethylene and oxygen alternately in a stepwise manner according to Table 1. The experimental data is recorded as Ag-2.

[0071] Example 3:

[0072] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0073] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 3500h -1, heat to 100°C under nitrogen atmosphere at a heating rate of 40°C / h, introduce oxygen until the concentration reaches 2%, and maintain the temperature for 8h.

[0074] S2. Heating at a rate of 20°C / h to 260°C, stop introducing oxygen, place the catalyst back in a pure nitrogen atmosphere, and maintain the temperature for 6 hours.

[0075] S3, lower the temperature to 225℃ and maintain the airspeed at 3500h -1 After adding ethylene to a concentration of over 5%, slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is above 0.5% and below 1%. The catalyst reaction is stable for 4 hours. Then, 0.8 ppm of ethylene monochloride is added to increase the catalyst selectivity to a stable level.

[0076] S4. After the catalyst selectivity stabilizes, reduce the concentration of ethylene chloride to 0.4 ppm and continue adding it. Then, increase the concentration of ethylene and oxygen alternately in a stepwise manner according to Table 1. The experimental data is recorded as Ag-3.

[0077] Example 4:

[0078] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0079] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 3500h -1 , heat to 160°C under nitrogen atmosphere at a heating rate of 40°C / h, introduce oxygen until the concentration reaches 2%, and maintain the temperature for 8h.

[0080] S2. Heating at a rate of 20°C / h to 235°C, stopping the introduction of oxygen, placing the catalyst back in a pure nitrogen atmosphere, and maintaining the temperature for 6 hours.

[0081] S3, lower the temperature to 225℃ and maintain the airspeed at 3500h -1 After adding ethylene to a concentration of over 5%, slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is above 0.5% and below 1%. The catalyst reaction is stable for 4 hours. Then, 0.8 ppm of ethylene monochloride is added to increase the catalyst selectivity to a stable level.

[0082] S4. After the catalyst selectivity stabilizes, reduce the concentration of ethylene chloride to 0.4 ppm and continue adding it. Then, increase the concentration of ethylene and oxygen alternately in a stepwise manner according to Table 1. The experimental data is recorded as Ag-4.

[0083] Example 5:

[0084] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0085] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 3500h -1 , heat to 160°C under nitrogen atmosphere at a heating rate of 40°C / h, introduce oxygen until the concentration reaches 2%, and maintain the temperature for 8h.

[0086] S2. Heating at a rate of 20°C / h to 260°C, stop introducing oxygen, place the catalyst back in a pure nitrogen atmosphere, and maintain the temperature for 6 hours.

[0087] S3, lower the temperature to 225℃ and maintain the airspeed at 3500h -1 After adding ethylene to a concentration of over 5%, slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is above 0.5% and below 1%. The catalyst reaction is stable for 4 hours. Then, 2 ppm of ethylene monochloride is added to increase the catalyst selectivity to a stable level.

[0088] S4. After the catalyst selectivity stabilizes, reduce the concentration of ethylene chloride to 1 ppm and continue adding it. Then, increase the concentrations of ethylene and oxygen alternately in a stepwise manner according to Table 1. The experimental data is recorded as Ag-5.

[0089] Comparative Example 1:

[0090] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0091] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 3500h -1 , heating rate 20 ℃ / h, heating to 260 ℃, the catalyst was placed in a pure nitrogen atmosphere again, and the temperature was maintained for 6h.

[0092] S2. Lower the temperature to 225℃ and maintain the airspeed at 3500h -1 After adding ethylene to a concentration of over 5%, slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is above 0.5% and below 1%. The catalyst reaction is stable for 4 hours. Then, 0.8 ppm of ethylene monochloride is added to increase the catalyst selectivity to a stable level.

[0093] S3. After the catalyst selectivity stabilizes, ethyl chloride is reduced to 0.4 ppm and continuously added. Then, the concentrations of ethylene and oxygen are alternately increased in a stepwise manner according to Table 1. The experimental data are recorded as Ag-A.

[0094] Comparative Example 2:

[0095] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0096] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 3500h -1 , heat to 160°C under nitrogen atmosphere at a heating rate of 40°C / h, introduce oxygen until the concentration reaches 2%, and maintain the temperature for 8h.

[0097] S2. Stop the oxygen flow and place the catalyst back in a pure nitrogen atmosphere. Raise the temperature to 225°C at a rate of 20°C / h. Maintain the air velocity at 3500 h -1 After adding ethylene to a concentration of over 5%, slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is above 0.5% and below 1%. The catalyst reaction is stable for 4 hours, and then 0.8ppm of ethylene monochloride is added to increase the catalyst selectivity to a stable level.

[0098] S3. After the catalyst selectivity stabilizes, ethylene chloride is reduced to 0.4 ppm and continuously added. Then, the concentrations of ethylene and oxygen are alternately increased in a stepwise manner according to Table 1. The experimental data are recorded as Ag-B.

[0099] Comparative Example 3:

[0100] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0101] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 3500h -1 , heat to 160°C under nitrogen atmosphere at a heating rate of 40°C / h, introduce oxygen until the concentration reaches 2%, and maintain the temperature for 8h.

[0102] S2. Heating at a rate of 20°C / h to 260°C, stop introducing oxygen, place the catalyst back in a pure nitrogen atmosphere, and maintain the temperature for 6 hours.

[0103] S3, lower the temperature to 225℃ and maintain the airspeed at 3500h -1 First, add 0.8ppm of ethylene monochloride, then add ethylene to a concentration of over 5%, and then slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is above 0.5% and below 1%. The catalyst reaction is stable for 4 hours, and the catalyst selectivity is increased to a stable level.

[0104] S4. After the catalyst selectivity stabilized, ethyl chloride was reduced to 0.4 ppm and continuously added. Then, the concentrations of ethylene and oxygen were alternately increased in a stepwise manner as shown in Table 1. The experimental data are recorded as Ag-C.

[0105] Comparative Example 4:

[0106] A method for acclimating an ethylene epoxide silver catalyst comprises the following steps:

[0107] S1. Place the ethylene epoxide silver catalyst to be acclimated in the reactor, and maintain the space velocity at 3500h -1 , heat to 160°C under nitrogen atmosphere at a heating rate of 40°C / h, introduce oxygen until the concentration reaches 2%, and maintain the temperature for 8h.

[0108] S2. Heating at a rate of 20°C / h to 260°C, stop introducing oxygen, place the catalyst back in a pure nitrogen atmosphere, and maintain the temperature for 6 hours.

[0109] S3, lower the temperature to 225℃ and maintain the airspeed at 3500h -1 After adding ethylene to a concentration of over 5%, slowly increase the oxygen concentration to 1%. After ethylene oxide is detected in the outlet detector, increase the ethylene concentration to 12% and the oxygen concentration to 3%, so that the outlet detector oxygen concentration is higher than 0.5% and lower than 1%. The catalyst reaction is stable for 4 hours to increase the catalyst selectivity to a stable level.

[0110] S4. Then, the concentrations of ethylene and oxygen are alternately increased in a step-by-step manner according to Table 1. The experimental data are recorded as Ag-D.

[0111] Results: Method for determining the performance of silver catalyst:

[0112] Reaction conditions in the present invention are:

[0113] Reaction pressure 1.8MPa; space velocity 3500h -1 ; Reaction temperature 215~240℃.

[0114] The selectivity (S) was calculated using the following formula after volume shrinkage correction was performed on the measurement results:

[0115] S2=ΔEO / (ΔEO+0.5*ΔCO2)*100%

[0116] S3=6*ΔEO*100% / (5*ΔEO+2*ΔO2)

[0117] S=(S2+S3) / 2

[0118] Where ΔEO is the concentration difference of ethylene oxide in the gas at the inlet and outlet of the reactor, ΔCO2 is the concentration difference of carbon dioxide in the gas at the inlet and outlet of the reactor, and ΔO2 is the concentration difference of oxygen in the gas at the inlet and outlet of the reactor.

[0119] Table 2 Silver catalyst selectivity

[0120]

[0121]

[0122] Based on the table above, the results show that:

[0123] Example 1 combines four steps: oxygen removal of organic matter, high temperature formation of silver particle mirror enrichment, excessive chloride concentration reaction initiation, and appropriate concentration of chloride to promote the reaction, ultimately obtaining experimental results of high selectivity and high activity.

[0124] In other comparative examples and embodiments, insufficient or missing treatment conditions will lead to reduced catalyst selectivity and decreased activity.

[0125] Therefore, using appropriate catalyst acclimation methods may result in a final selectivity gap of up to about 10% in the catalyst.

[0126] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. A method for acclimating an ethylene epoxide silver catalyst, characterized in that: The steps include: S1. Under a pure nitrogen atmosphere, place the ethylene epoxide silver catalyst to be acclimated in the reaction system, increase the temperature at a certain rate, and introduce oxygen until the concentration is stable. Maintain the reaction under this temperature and atmosphere conditions. S2, then stop the oxygen supply, and after the oxygen concentration is lower than the primary set concentration, increase the reaction temperature and maintain the reaction under this temperature and atmosphere conditions; S3, after the reaction in S2 is completed, the temperature is lowered, the catalyst volume space velocity is increased, and then ethylene is added. When the ethylene concentration reaches above the initial concentration, the oxygen concentration is slowly increased to the intermediate concentration; after the ethylene epoxidation reaction occurs, the oxygen concentration is continued to be increased to the third concentration, and the ethylene concentration is increased to the intermediate concentration to ensure and maintain the oxygen concentration at the reaction outlet; S4, if the ethylene oxide at the outlet of the reaction does not change within the expected time, slowly add chloride to stabilize the ethylene epoxide silver catalyst to be acclimated; S5. After the tamed ethylene silver epoxide catalyst is stabilized, the amount of chloride added is reduced to half of the initial concentration. Then, according to the industrial application scenario, the reactant concentration is increased to the target value. Then, the ethylene, oxygen concentration and chloride addition amount are alternately increased in a step-by-step manner to complete the taming.

2. The acclimation method of an ethylene epoxide silver catalyst according to claim 1, wherein: In S1, the temperature is raised to 150-160°C at a rate of 10-100°C / h; The oxygen is introduced until the oxygen mass concentration is stabilized at 1-2%; Keep the reaction under the temperature and atmosphere conditions for 4 to 8 hours; The volume space velocity of the ethylene epoxide silver catalyst to be acclimated is not less than 2000h -1 .

3. The acclimation method of an ethylene epoxide silver catalyst according to claim 1, wherein: In said S2, the primary set concentration of oxygen is less than 0.1%; Raising the reaction temperature to 240-260° C.; The heating rate does not exceed 20-100℃ / h; The reaction is maintained at this temperature and atmosphere for 6 to 24 hours.

4. The acclimation method of an ethylene epoxide silver catalyst according to claim 1, wherein: In S3, the temperature is lowered to 215-240°C; the catalyst volume space velocity is increased to 3000-6000h -1 ; When the ethylene concentration reaches an initial concentration of 5% or more, the oxygen concentration is slowly increased to an intermediate concentration of 1%; After the ethylene epoxidation reaction occurs, continue to increase the oxygen concentration to the tertiary concentration of 1-3%, and increase the ethylene concentration to the intermediate concentration of 12-15%, ensuring and maintaining the oxygen concentration at the reaction outlet not less than 0.5% and not more than 1%.

5. The acclimation method of an ethylene epoxide silver catalyst according to claim 1, wherein: In said S4, the expected time is 4 hours; The chloride is ethyl chloride; The concentration of the chloride is 0.5 to 10 ppm.

6. The acclimation method of an ethylene epoxide silver catalyst according to claim 1, characterized in that: In the step S5, the amount of chloride added is 0.3 to 5 ppm.

7. The acclimation method of an ethylene epoxide silver catalyst according to claim 1, characterized in that: In S5, the target values ​​of reactant concentrations are: ethylene concentration 30%, oxygen concentration 6.5%.

8. The acclimation method of an ethylene epoxide silver catalyst according to claim 1, characterized in that: In said S5, when the concentrations of ethylene and oxygen are alternately increased in a stepwise manner, each increase shall not be adjusted to a concentration higher than 1%; The concentration of the chloride is adjusted in the range of 2 to 20 ppm.

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