CN110357837B - Ethylene epoxidation method - Google Patents

Ethylene epoxidation method Download PDF

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CN110357837B
CN110357837B CN201810254403.7A CN201810254403A CN110357837B CN 110357837 B CN110357837 B CN 110357837B CN 201810254403 A CN201810254403 A CN 201810254403A CN 110357837 B CN110357837 B CN 110357837B
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ethylene
epoxidation
chlorine
carbon dioxide
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CN110357837A (en
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孙欣欣
任冬梅
李金兵
代武军
汤之强
王淑娟
韩红苓
林强
王辉
林伟
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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China Petroleum and Chemical Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/02—Boron or aluminium; Oxides or hydroxides thereof
    • B01J21/04—Alumina
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/66—Silver or gold
    • B01J23/68—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/688—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with manganese, technetium or rhenium
    • B01J35/612—
    • B01J35/643—
    • B01J35/647—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0201—Impregnation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D301/00—Preparation of oxiranes
    • C07D301/02—Synthesis of the oxirane ring
    • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
    • C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
    • C07D301/08—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
    • C07D301/10—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase with catalysts containing silver or gold
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
    • C07D303/02—Compounds containing oxirane rings
    • C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms

Abstract

The invention belongs to the field of olefin epoxidation, and particularly relates to an ethylene epoxidation method. The method comprises the following steps: subjecting a feed gas to an epoxidation reaction in the presence of an epoxidation catalyst, the feed gas comprising ethylene, oxygen, carbon dioxide, a chlorine-containing component, and a ballast gas, the epoxidation catalyst being a high selectivity silver catalyst; the epoxidation reaction comprises the following steps: normally starting the epoxidation reaction by using an external heat source, reducing the concentration of the chlorine-containing component and the concentration of ethylene after the concentration of the outlet ethylene oxide is more than 2.0 mol% and is maintained for more than 60 hours, increasing the concentration of carbon dioxide after the temperature of the middle bed layer of the reactor is constant for more than 60 hours, and restoring the concentration of the chlorine-containing component, the concentration of ethylene and the concentration of carbon dioxide to the normal starting concentration after the temperature of the middle bed layer of the reactor is constant for more than 60 hours again. The method can obviously improve the selectivity of the catalyst without increasing excessive energy consumption.

Description

Ethylene epoxidation method
Technical Field
The invention belongs to the field of olefin epoxidation, and particularly relates to an ethylene epoxidation method.
Background
Two methods for industrially producing ethylene oxide are a chlorohydrin method and a direct oxidation method. The chlorohydrin process is the oldest process for producing ethylene oxide, but since the chlorohydrin process consumes a large amount of alkali and chlorine, causes serious pollution, causes serious corrosion of equipment, and the like, the direct oxidation process gradually replaces the dominant chlorohydrin process.
At present, the method for industrially producing the ethylene oxide in the world is directly obtained by oxidizing ethylene, and a silver catalyst is adopted. Ethylene and oxygen react directly on metallic silver to produce ethylene oxide, which is exothermic mainly as a side reaction, but the heat of reaction of the side reaction is more than ten times that of the main reaction, and therefore, it is necessary to manufacture a suitable catalyst and strictly control certain process conditions to prevent an increase in the side reaction (complete oxidation). Otherwise, the side reaction is accelerated, which may cause deterioration of the operation conditions, thereby causing a vicious cycle, and the occurrence of "runaway" of the catalyst bed may occur.
The production of ethylene oxide continues to increase year by year, and the research on ethylene oxide processes and catalysts continues to be intensive, and reports on the process operation of high selectivity silver catalysts are of great interest.
Chinese patent CN101801944B, limited liability for scientific design in the united states, mentions a method for achieving a controlled start-up temperature for an epoxidation process by heating the epoxidation reactor with an external heat source to a maximum temperature, maintaining the feed gas flow at 25% to 100% of the design rate, introducing at least an olefin and then oxygen into the reactor feed gas once the reactor reaches a first temperature, adjusting the concentrations of olefin and oxygen to produce a heat of reaction that raises the reactor gas flow to 100% of the design, and still having sufficient heat of reaction to raise the temperature of the reactor to a second temperature, the second temperature being higher than the first temperature and higher than the reactor temperature achievable with the external heat source.
International shell limited chinese patent CN103502229B provides a method for improving selectivity using highly selective EO catalysts. The starting method comprises the following steps: initiating an epoxidation reaction by reacting a feed gas composition comprising ethylene and oxygen without moderator in the presence of an epoxidation catalyst at a first temperature of 180 to 210 ℃; the first temperature is raised over a period of 6 to 50 hours to a second temperature of 230 to 290 ℃ while simultaneously adding a sufficient concentration of moderator so that the amount of moderator adsorbed on the catalyst after said second temperature is reached is 10 to 50g/m3A catalyst; maintaining the second temperature for 50 to 350 hours while adjusting the feed gas composition to contain 0.5% to 25% CO2(ii) a The second temperature is reduced to a third temperature while simultaneously increasing the moderator concentration to a level greater than the sufficient concentration.
Although the above patents improve the selectivity of the catalyst by adjusting the first temperature and the second temperature at start-up, the second temperature is too high and the energy consumption increases, which increases the cost, and therefore, it is necessary to continue optimization of the olefin epoxidation process.
Disclosure of Invention
It is an object of the present invention to provide a process for the epoxidation of ethylene, whereby the selectivity of the catalyst can be improved by optimizing the start-up process without increasing excessive energy consumption.
To achieve the above object, the present invention provides an ethylene epoxidation process comprising: subjecting a feed gas to an epoxidation reaction in the presence of an epoxidation catalyst, the feed gas comprising ethylene, oxygen, carbon dioxide, a chlorine-containing component, and a ballast gas, the epoxidation catalyst being a high selectivity silver catalyst;
the epoxidation reaction comprises the following steps: normally starting the epoxidation reaction by utilizing an external heat source, reducing the concentration of the chlorine-containing component and the concentration of ethylene after the concentration of the outlet ethylene oxide is more than 2.0 wt% and is maintained for more than 60 hours, increasing the concentration of carbon dioxide after the temperature of the middle bed layer of the reactor is constant for more than 60 hours, and restoring the concentration of ethylene and the concentration of carbon dioxide to the normal starting concentration after the temperature of the middle bed layer of the reactor is constant for more than 60 hours again.
The invention has the advantages that: after the reaction is normally started, the high-selectivity silver catalyst has higher selectivity by regulating the ethylene concentration, the chlorine-containing component concentration and the carbon dioxide concentration in a specific mode. The method is used in the industrial operation of preparing the ethylene oxide by the epoxidation of the ethylene, the selectivity of the catalyst is obviously improved, and the method has wide application prospect.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Detailed Description
Preferred embodiments of the present invention will be described in more detail below.
The present invention provides a process for the epoxidation of ethylene, which process comprises: subjecting a feed gas to an epoxidation reaction in the presence of an epoxidation catalyst, the feed gas comprising ethylene, oxygen, carbon dioxide, a chlorine-containing component, and a ballast gas, the epoxidation catalyst being a high selectivity silver catalyst;
the epoxidation reaction comprises the following steps: normally starting the epoxidation reaction by using an external heat source, reducing the concentration of the chlorine-containing component and the concentration of ethylene after the concentration of the outlet ethylene oxide is more than 2.0 mol% and is maintained for more than 60 hours, increasing the concentration of carbon dioxide after the temperature of the middle bed layer of the reactor is constant for more than 60 hours, and restoring the concentration of ethylene and the concentration of carbon dioxide to the normal starting concentration after the temperature of the middle bed layer of the reactor is constant for more than 60 hours again.
In the present invention, the concept of the term "normal start-up" is well known to those skilled in the art and means that a production level of ethylene oxide comparable to the full production level is obtained.
The feed gas comprises ethylene, oxygen, carbon dioxide, chlorine-containing components, and a stabilizing gas, optionally containing other alkane gases. The ballast gas includes, but is not limited to: nitrogen, argon, helium or mixtures thereof. The chlorine-containing component may be C1-C8At least one of the chlorinated hydrocarbons, including but not limited to: methyl chloride, ethyl chloride, ethylene dichloride, vinyl chloride or mixtures thereof. Such other alkane gases include, but are not limited to: methane, ethane, propane or mixtures thereof.
Specifically, the conditions for normal start-up preferably include: the concentration of each component in the feed gas is normal start concentration, and further preferably, the normal start concentration of oxygen is 5-8 mol%, the normal start concentration of carbon dioxide is less than or equal to 2 mol%, the normal start concentration of ethylene is 25-30 mol%, and the normal start concentration of chlorine-containing components is less than or equal to 1 mol%, which are molar ratios in the total volume of the feed gas.
In addition, the conditions for normal start-up further include: the starting temperature is a normal starting temperature, preferably, the normal starting temperature is 180-.
According to the present invention, the fine tuning of the chlorine-containing component will affect the selectivity of the high selectivity silver catalyst. The reduced concentration of the chlorine-containing component is preferably reduced to 10% -90% of the normal start-up concentration of the chlorine-containing component; preferably to 30% -60% of the normal start-up concentration of the chlorine-containing component.
According to the invention, the reduced ethylene concentration is preferably reduced to 10% to 50% of the normal start-up concentration of ethylene; preferably to a level of from 30% to 45% of the normal start-up concentration of ethylene.
According to the present invention, increasing the carbon dioxide concentration enables the reaction temperature to be increased. The concentration of the carbon dioxide is preferably increased to 1.1-3.5 times of the normal starting concentration of the carbon dioxide; preferably 1.5-3 times the normal start-up concentration of carbon dioxide.
The process of the present invention is only applicable to high selectivity silver catalysts. The concept and scope of the term "high selectivity silver catalyst" in the present invention is well known to those skilled in the art and refers to silver catalysts for epoxidation having a low space time yield with a maximum selectivity between 89 and 91%. The highly selective silver catalyst may be prepared or commercially available. Corresponding to the "high selectivity silver catalyst", there are also "high activity silver catalysts" and "high performance silver catalysts" in the art. The high-activity silver catalyst is a silver catalyst for epoxidation which has a low initial operating temperature and a high applicable space-time yield in an industrial plant. The high-performance silver catalyst is a silver catalyst for epoxidation, which has higher applicable space-time yield than a high-selectivity silver catalyst and the selectivity of the catalyst is more than 88%. Both types of catalysts may also be prepared or commercially available. The skilled person is able to distinguish the three catalyst types explicitly and can select the appropriate type of catalyst according to the actual needs.
Preferably, the high-selectivity silver catalyst in the invention is a low-silver-content high-selectivity silver catalyst, and the content of silver element is 10-20 wt% based on the total weight of the catalyst.
According to a preferred embodiment of the present invention, the high selectivity silver catalyst comprises the following components, based on the total weight of the catalyst:
alpha-alumina carrier with specific surface of 1.0-5.0m2The water absorption is more than or equal to 50 percent, the crushing strength is 50-200N/particle, and the total pore volume is counted, the pores with the pore diameter of 0.1-5 mu m account for 40-80 percent, and the pores with the pore diameter of more than or equal to 10 mu m account for 10-50 percent;
Figure BDA0001608632960000051
according to the present invention, the shape of the carrier may be a sphere, a block, a cylinder, a single-hole cylinder, a porous cylinder, a raschig ring, a clover, a honeycomb, etc., preferably a single-hole cylinder or a porous cylinder. The carrier particles preferably have an equivalent diameter of 5 to 10mm, which means the diameter of a sphere having the same volume of carrier particles.
The catalyst can be prepared by a method comprising the following steps: soaking the alpha-alumina carrier in a solution of a silver compound, an organic amine compound and an auxiliary agent, and then filtering and activating heat treatment to obtain the alpha-alumina carrier; the promoter comprises an alkali metal promoter, an alkaline earth metal promoter, an optional rhenium promoter and an optional rhenium co-promoter. The term "rhenium co-promoter" as used herein is also referred to as "rhenium promoter co-promoter".
In the preparation method of the silver catalyst, the silver compound comprises one or more of silver oxide, silver nitrate and silver oxalate. In the above method for producing a silver catalyst, the alkali metal promoter may be a compound of lithium, sodium, potassium, rubidium and cesium, such as a nitrate, sulfate or hydroxide thereof, or a combination of any two or more of the foregoing compounds; preferably, the alkali metal assistant is cesium sulfate and/or cesium nitrate. In the above method for preparing silver catalyst, the alkaline earth metal promoter is selected from one or more of compounds of magnesium, calcium, strontium and barium, such as their oxides, oxalates, sulfates, acetates or nitrates, or a combination of any two or more of the foregoing compounds; preferably, the alkaline earth metal auxiliary agent is a barium and/or strontium compound; more preferably, the alkaline earth metal auxiliary agent is barium acetate and/or strontium acetate. The alkaline earth metal promoter may be applied to the support before, simultaneously with, or after impregnation of the silver, or may be impregnated on the support after the silver compound has been reduced. In the above silver catalyst preparation method, the rhenium promoter may be an oxide, perrhenic acid, perrhenate of rhenium, or a mixture of any two or more of the foregoing compounds; preferred rhenium promoters are perrhenic acid and perrhenates such as perrhenic acid, cesium perrhenate, ammonium perrhenate and the like. According to some embodiments of the present invention, in the above method for preparing a silver catalyst, the rhenium co-promoter is selected from one or more of oxyanions in the form of salts or acids of cerium, sulfur, molybdenum, tungsten, and chromium. In the present invention, the rhenium promoter and the co-promoter for the rhenium promoter may be applied to the carrier before, simultaneously with, or after impregnation of the silver, or may be impregnated on the carrier after the silver compound has been reduced. The activity, selectivity and stability of activity and selectivity of the resulting silver catalyst can be further improved by adding a rhenium promoter and a co-promoter for the rhenium promoter. In the above silver catalyst preparation method, the organic amine compound may be any organic amine compound suitable for preparing a silver catalyst for ethylene oxide production, as long as the organic amine compound is capable of forming a silver amine complex with a silver compound, such as pyridine, butylamine, ethylenediamine, 1, 3-propanediamine, ethanolamine, or a mixture thereof; preferably, the organic amine compound is a mixture of ethylenediamine and ethanolamine.
In the present invention, the reactor used for the epoxidation of ethylene is generally a fixed bed tubular reactor packed with catalyst in a plurality of parallel elongated tubes to obtain Ethylene Oxide (EO) product and by-products at the outlet of the reactor. The EO product from the reactor outlet is separated from the reaction product and recovered using conventional methods, with carbon dioxide and other by-products either completely or partially removed and returned to the recycle gas at the reactor inlet. The process for the epoxidation of ethylene requires an external heat source to provide the initial temperature, typically 180 ℃ to 220 ℃, and a reactor pressure of 1 to 30 atmospheres.
The invention is further illustrated by the following examples.
The low silver content high selectivity silver catalyst used in the examples had a diameter of
Figure BDA0001608632960000062
Comprises the following components:
alpha-alumina carrier with specific surface area of 1.8m2The water absorption rate is 55 percent, the crushing strength is 99N/grain, and according to the total pore volume, the pores with the pore diameter of 0.1-5 mu m account for 60 percent, and the pores with the pore diameter of more than or equal to 10 mu m account for 40 percent;
Figure BDA0001608632960000061
the catalyst is prepared by the following method: mixing an organic amine aqueous solution with silver oxalate, adding an alkali metal auxiliary agent, an alkaline earth metal auxiliary agent, a rhenium auxiliary agent and a synergistic auxiliary agent thereof, uniformly mixing and stirring, putting the alpha-alumina carrier into a mixed liquid, soaking, and then carrying out heat treatment to obtain the catalyst.
In the following examples, a low silver content, high selectivity silver catalyst was loaded into a 9.3m catalyst reaction tube and reacted at the feed gas composition of table 1, with inert packing on the top and bottom of the bed, so that the catalyst bed was located in the constant temperature zone of the heating mantle.
The measurement conditions of the selectivity of the high-selectivity silver catalyst are shown in table 1.
TABLE 1
Figure BDA0001608632960000071
The reactor inlet and outlet gas compositions were continuously measured to stabilize to the above reaction conditions, the results were recorded and corrected for volume shrinkage, and the selectivity was calculated according to the following formula:
selectivity is
Figure BDA0001608632960000072
Wherein, Delta EO is the concentration difference of ethylene oxide in outlet gas and inlet gas of the reactor, Delta CO2The average of more than 10 sets of test data was taken as the test result on the same day, which is the difference in carbon dioxide concentration between the outlet gas and the inlet gas of the reactor.
The high activity catalyst used in the comparative example was purchased from the company petrochemical catalyst (beijing) in china.
Example 1
Heating the catalyst bed layer from room temperature to 180 ℃ by using an external heat source, setting the ethylene concentration in the feed gas to be 26 mol%, the oxygen concentration to be 7.2 mol%, the dichloroethane to be 3ppm, the carbon dioxide concentration to be 1 mol%, and the balance to be stable gas N2Carrying out normal starting reaction, keeping the EO concentration at the outlet of the reactor to be 2 mol%, and reducing the ethylene concentration to 10 mol% after maintaining for 72 h; the concentration of the chlorine-containing component is reduced to 1ppm,after the temperature of the middle bed layer of the reactor is constant for 72 hours, the concentration of the carbon dioxide is increased to 3 mol%, after the temperature of the middle bed layer of the reactor is constant for 72 hours again, the concentration of the ethylene, the concentration of the chlorine-containing component and the concentration of the carbon dioxide are recovered to the normal starting concentration, and at the moment, the selectivity of the catalyst is increased to 84.5% from 82.5% of the normal starting.
Example 2
Heating the catalyst bed layer from room temperature to 200 deg.C with an external heat source, setting the ethylene concentration in the feed gas to 25 mol%, the oxygen concentration to 6.8 mol%, the dichloroethane to 8ppm, the carbon dioxide concentration to 0.8 mol%, and the balance stabilized gas N2Carrying out normal starting reaction, keeping the EO concentration at the outlet of the reactor to be 2 mol%, and reducing the ethylene concentration to 4 mol% after maintaining for 68 h; the concentration of the chlorine-containing component is reduced to 1.6ppm, the concentration of the carbon dioxide is increased to 1.6 mol% after the temperature of the middle bed layer of the reactor is constant for 68 hours, the concentration of the ethylene, the concentration of the chlorine-containing component and the concentration of the carbon dioxide are restored to normal starting concentrations after the temperature of the middle bed layer of the reactor is constant for 68 hours again, and the selectivity of the catalyst is increased to 83.7% from 82.5% of normal starting at the moment.
Example 3
Heating the catalyst bed layer from room temperature to 220 deg.C with an external heat source, setting the ethylene concentration in the feed gas to 28 mol%, the oxygen concentration to 5.4 mol%, the dichloroethane to 6ppm, the carbon dioxide concentration to 1.5 mol%, and the balance stabilized gas N2Carrying out normal starting reaction, keeping the EO concentration at the outlet of the reactor to be 2 mol%, and reducing the ethylene concentration to 12.5 mol% after maintaining for 76 h; the concentration of the chlorine-containing component is reduced to 4.8ppm, the concentration of the carbon dioxide is increased to 2.25 mol% after the temperature of the middle bed layer of the reactor is constant for 76h, the concentration of the ethylene, the concentration of the chlorine-containing component and the concentration of the carbon dioxide are restored to normal starting concentration after the temperature of the middle bed layer of the reactor is constant for 76h again, and the selectivity of the catalyst is increased to 84.1% from 82.5% of normal starting at the moment.
Comparative example 1
The high-activity catalyst is selected, and compared with a high-selectivity catalyst, the high-activity catalyst is higher in applicable space-time yield, basically consistent in activity and lower in selectivity. For external useThe catalyst bed layer is heated from room temperature to 180 ℃ by a partial heat source, the ethylene concentration in the feed gas is set to be 26 mol%, the oxygen concentration is 7.2 mol%, the dichloroethane is 3ppm, the carbon dioxide concentration is 1 mol%, and the balance is stable gas N2Carrying out normal starting reaction, keeping the EO concentration at the outlet of the reactor to be 2 mol%, and reducing the ethylene concentration to 10 mol% after maintaining for 72 h; the concentration of the chlorine-containing component is reduced to 1ppm, the concentration of carbon dioxide is increased to 3 mol% after the temperature of the middle bed layer of the reactor is constant for 72h, the concentration of ethylene, the concentration of the chlorine-containing component and the concentration of carbon dioxide are restored to normal starting concentrations after the temperature of the middle bed layer of the reactor is constant for 72h again, and the selectivity of the catalyst is 80.5% when being not changed relative to the selectivity of the catalyst during normal starting.
It can be seen from the data of the examples and comparative examples that the ethylene epoxidation process of the present invention is only applicable to the high selectivity silver catalyst, and can further improve the selectivity of the high selectivity silver catalyst, thereby increasing the practical application value thereof.
Having described embodiments of the present invention, the foregoing description is intended to be exemplary, not exhaustive, and not limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims (11)

1. A process for the epoxidation of ethylene, which process comprises: subjecting a feed gas to an epoxidation reaction in the presence of an epoxidation catalyst, the feed gas comprising ethylene, oxygen, carbon dioxide, a chlorine-containing component, and a ballast gas, the epoxidation catalyst being a high selectivity silver catalyst;
the epoxidation reaction comprises the following steps: normally starting an epoxidation reaction by using an external heat source, reducing the concentration of the chlorine-containing component and the concentration of ethylene after the concentration of the outlet ethylene oxide is more than 2.0 mol% and is maintained for more than 60 hours, increasing the concentration of carbon dioxide after the temperature of a middle bed layer of the reactor is constant for more than 60 hours, and restoring the concentration of the chlorine-containing component, the concentration of ethylene and the concentration of carbon dioxide to the normal starting concentration after the temperature of the middle bed layer of the reactor is constant for more than 60 hours again;
the conditions for normal start-up of the epoxidation reaction include: the starting temperature is normal starting temperature, and the normal starting temperature is 180-220 ℃;
the high-selectivity silver catalyst comprises the following components:
alpha-alumina carrier with specific surface of 1.0-5.0m2The water absorption is more than or equal to 50 percent, the crushing strength is 50-200N/particle, and the total pore volume is counted, the pores with the pore diameter of 0.1-5 mu m account for 40-80 percent, and the pores with the pore diameter of more than or equal to 10 mu m account for 10-50 percent;
Figure FDA0002949232770000011
2. the ethylene epoxidation process of claim 1, wherein said conditions that normally initiate the epoxidation reaction comprise: the concentrations of the components in the feed gas were all normal start-up concentrations.
3. The process for the epoxidation of ethylene of claim 2, wherein the normal start-up concentration of oxygen is 5 to 8 mol%, the normal start-up concentration of carbon dioxide is 2 mol% or less, the normal start-up concentration of ethylene is 25 to 30 mol%, and the normal start-up concentration of chlorine-containing components is 1 mol% or less, all in molar ratios to the total volume of the feed gas.
4. A process for the epoxidation of ethylene according to any of claims 1-3, wherein said reduced concentration of chlorine-containing components is reduced to 10-90% of the normal start-up concentration of chlorine-containing components.
5. The ethylene epoxidation process of claim 4, wherein said reduced chlorine-containing component concentration is reduced to 30% -60% of the normal start-up concentration of chlorine-containing components.
6. The process for the epoxidation of ethylene according to any of claims 1-3, wherein said reduction of the ethylene concentration is between 10% and 50% of the normal start-up concentration of ethylene.
7. The ethylene epoxidation process of claim 6, wherein said reducing ethylene concentration is reduced to 30% -45% of the normal start-up concentration of ethylene.
8. The ethylene epoxidation process of any of claims 1-3, wherein said elevated carbon dioxide concentration is 1.1-3.5 times the normal start-up concentration of elevated carbon dioxide.
9. The ethylene epoxidation process of claim 8, wherein said elevated carbon dioxide concentration is 1.5-3 times the normal start-up concentration of elevated carbon dioxide.
10. The process for the epoxidation of ethylene according to any of claims 1-3, wherein said chlorine-containing component is C1-C8At least one of chlorinated hydrocarbons.
11. The ethylene epoxidation process of claim 1, wherein said high selectivity silver catalyst is prepared by a process comprising the steps of: soaking an alpha-alumina carrier in a solution of a silver compound, an organic amine compound and an auxiliary agent, and then filtering and activating heat treatment to prepare a silver catalyst; the promoter comprises an alkali metal promoter, an alkaline earth metal promoter, an optional rhenium promoter and an optional rhenium co-promoter.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004078737A1 (en) * 2003-02-28 2004-09-16 Shell Internationale Research Maatschappij B.V. A method of manufacturing ethylene oxide
CN1809419A (en) * 2003-04-01 2006-07-26 国际壳牌研究有限公司 An olefin epoxidation process and a catalyst for use in the process
CN103261177A (en) * 2010-12-08 2013-08-21 国际壳牌研究有限公司 Process for improving the selectivity of an EO catalyst
CN103502229A (en) * 2011-04-29 2014-01-08 国际壳牌研究有限公司 Process for improving the selectivity of an eo catalyst
CN104080778A (en) * 2011-12-09 2014-10-01 陶氏技术投资有限责任公司 Method of maintaining the value of an alkylene oxide production parameter in a process of making an alkylene oxide using a high efficiency catalyst

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004078737A1 (en) * 2003-02-28 2004-09-16 Shell Internationale Research Maatschappij B.V. A method of manufacturing ethylene oxide
CN1809419A (en) * 2003-04-01 2006-07-26 国际壳牌研究有限公司 An olefin epoxidation process and a catalyst for use in the process
CN103261177A (en) * 2010-12-08 2013-08-21 国际壳牌研究有限公司 Process for improving the selectivity of an EO catalyst
CN103502229A (en) * 2011-04-29 2014-01-08 国际壳牌研究有限公司 Process for improving the selectivity of an eo catalyst
CN104080778A (en) * 2011-12-09 2014-10-01 陶氏技术投资有限责任公司 Method of maintaining the value of an alkylene oxide production parameter in a process of making an alkylene oxide using a high efficiency catalyst

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
EFFECT OF ADDITIVE IN FEEDSTOCK ON PERFORMANCE OF Ag-MoO3/ZrO2 CATALYST FOR PROPYLENE EPOXIDATION BY MOLECULAR OXYGEN;Guojie Jin等;《React.Kinet.Catal.Lett.》;20061231;第89卷(第2期);第253-260页 *
保持环氧乙烷催化剂的高选择性提高装置效益;祝石华;《石油化工》;19871231;第16卷;第583-589页 *

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