CN112125869B - Method for preparing ethylene oxide by ethylene epoxidation - Google Patents

Method for preparing ethylene oxide by ethylene epoxidation Download PDF

Info

Publication number
CN112125869B
CN112125869B CN201910555773.9A CN201910555773A CN112125869B CN 112125869 B CN112125869 B CN 112125869B CN 201910555773 A CN201910555773 A CN 201910555773A CN 112125869 B CN112125869 B CN 112125869B
Authority
CN
China
Prior art keywords
silver
zirconium
compound
chromium
content
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201910555773.9A
Other languages
Chinese (zh)
Other versions
CN112125869A (en
Inventor
林伟
李旻旭
王辉
高立新
崔秉全
樊一琼
隗永清
段红艳
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
Original Assignee
Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sinopec Beijing Research Institute of Chemical Industry, China Petroleum and Chemical Corp filed Critical Sinopec Beijing Research Institute of Chemical Industry
Priority to CN201910555773.9A priority Critical patent/CN112125869B/en
Publication of CN112125869A publication Critical patent/CN112125869A/en
Application granted granted Critical
Publication of CN112125869B publication Critical patent/CN112125869B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • 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
    • 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
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/24—Chromium, molybdenum or tungsten
    • B01J23/26—Chromium
    • 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
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Catalysts (AREA)

Abstract

The invention belongs to the field of catalysts, and relates to a method for preparing ethylene oxide by ethylene epoxidation. The method comprises the following steps: mixing a silver catalyst, ethylene, oxygen, a stabilizing gas and chloride in a reactor to perform ethylene epoxidation, controlling the concentration of the chloride to be stabilized at 1-6 ppm after the reactor is operated, and reducing the concentration of the chloride to 0.1-1 ppm when the concentration of ethylene oxide at the outlet of the reactor reaches 0.5-3.0 mol%. The Cr compound and the Zr compound are added into the carrier to prepare the alumina carrier, the silver catalyst is prepared from the carrier, and the selectivity of the silver catalyst can be obviously improved in a short time by combining the adjustment of the chloride concentration in the reactor.

Description

Method for preparing ethylene oxide by ethylene epoxidation
Technical Field
The invention belongs to the field of catalysts, and particularly relates to a method for preparing ethylene oxide by ethylene epoxidation.
Background
Under the action of silver catalyst, ethylene is oxidized to produce ethylene oxide and side reaction to produce carbon dioxide and water, and the activity, selectivity and stability are the main performance indexes of silver catalyst. The activity refers to the reaction temperature required when the production process of the ethylene oxide reaches a certain reaction load; the lower the reaction temperature, the higher the activity of the catalyst. Selectivity refers to the ratio of the moles of ethylene converted to ethylene oxide in the reaction to the total reacted moles of ethylene. Stability is expressed as the rate of decline of activity and selectivity, with the lower the rate of decline the better the stability of the catalyst. The use of silver catalysts with high activity, high selectivity and good stability in the process of producing ethylene oxide by oxidizing ethylene can greatly improve the economic benefit, so that the preparation of silver catalysts with high activity, high selectivity and good stability is the main direction of the research of silver catalysts. The performance of the silver catalyst is not only important in relation to the composition of the catalyst and the preparation method thereof, but also important in relation to the performance of the carrier used in the catalyst and the preparation thereof.
The preparation method of the silver catalyst in the prior art comprises two processes of preparing a porous carrier (such as alumina) and applying an active component and an auxiliary agent to the carrier.
The addition of other components to the alumina carrier to improve the performance of the silver catalyst is an important research direction, which includes the addition of alkaline earth metal oxides or other salt compounds. EP0150238(US4428863) uses small amounts of barium aluminate or barium silicate binder in the manufacture of high purity, low surface alumina supports, and claims to improve the crush strength and attrition resistance of the supports, the specific surface of the supports prepared being less than 0.3m 2 The catalysts prepared have a low activity and selectivity per gram. US5384302 claims to pretreat alpha-Al by pretreatment 2 O 3 The reduction of Na, K, Ca and Al ion contents in the carrier can improve the crushing strength and the wear resistance of the carrier. US5739075 shows that the selectivity of the catalyst is reduced at a rate lower than that of a silver catalyst prepared by depositing a promoter amount of a rare earth metal and another promoter amount of a metal salt (an alkaline earth metal or a group VIII transition metal) on the surface of an alumina carrier in advance, and then calcining the resulting carrierCatalyst samples without pre-deposition treatment.
Fluoride is widely used as a mineralizer in the preparation process of an alumina carrier. CN1034678A mixes alpha-alumina trihydrate and pseudo-alpha-alumina monohydrate with proper granularity and proportion, carbonaceous material, fluxing agent, fluoride, binder and water, kneads and shapes, and prepares the alpha-alumina carrier after drying and roasting. The specific surface area of the carrier is 0.2-2 m 2 (ii)/g, pores with a pore radius of greater than 30 μm account for less than 25% of the total pore volume; the carrier is used for preparing ethylene oxide by oxidizing ethylene after being impregnated with a silver compound and a cocatalyst and being dried and activated, and the selectivity is up to 83-84%. CN101007287A mixes alpha-alumina trihydrate with a certain particle size, pseudo-alpha-alumina monohydrate, a certain amount of combustible carbon-containing material, fluxing agent, fluoride and optional heavy alkaline earth metal compound, adds adhesive and water after mixing evenly, kneads evenly, extrudes and dries and bakes to prepare alpha-alumina carrier; the specific surface of the carrier is 0.2-2.0 m 2 The pore volume is 0.35-0.85 ml/g, the water absorption rate is more than or equal to 30%, and the crushing strength is 30-120N/grain. The carrier is soaked with the solution of silver-amine complex, alkali metal compound and alkaline earth metal compound, and after drying and activation, the silver catalyst is prepared for preparing epoxy ethane by ethylene epoxidation. CN1634652A in the preparation of the carrier, a pore-forming agent is not used, but alpha-alumina trihydrate is directly mixed with pseudo-monohydrate alumina, a fluxing agent and fluoride according to a certain proportion, a binder and water are added after the mixture is uniformly mixed, the mixture is uniformly kneaded, extruded and molded, and the alpha-alumina carrier is prepared after drying and roasting. The specific surface of the carrier prepared by the method is 0.2-2.0 m 2 The pore volume is 0.35-0.85 ml/g, the water absorption rate is more than or equal to 30%, and the crushing strength is 20-90N/grain. The carrier is soaked with the solution of silver-amine complex, alkali metal compound and alkaline earth metal compound, and after drying and activation, the silver catalyst is prepared for preparing ethylene oxide by ethylene epoxidation.
Although the above patent documents respectively adopt methods of adding alkaline earth metal compounds or fluorides to alumina raw materials to improve alumina carriers, and bring about different degrees of improvement on the activity and selectivity of the catalyst, with the large-scale industrial application of silver catalysts with medium and high selectivity, the requirements of the silver catalysts and the carrier performance and application process thereof in the field are continuously increasing. Therefore, there is still a need to further improve the performance of silver catalysts and optimize the application process.
Disclosure of Invention
In view of the above-mentioned state of the art, the inventors of the present invention have conducted extensive and intensive experimental studies in the fields of silver catalysts, alumina carriers thereof, application processes thereof, and the like, and found that adding a Cr compound and a Zr compound to a carrier to prepare an alumina carrier and preparing a silver catalyst from the carrier can significantly improve the selectivity of the silver catalyst in a short time in combination with the adjustment of the chloride concentration in the reactor.
Specifically, the invention provides a method for preparing ethylene oxide by ethylene epoxidation, which comprises the following steps: mixing a silver catalyst, ethylene, oxygen, a stabilizing gas and chloride in a reactor to perform ethylene epoxidation, controlling the concentration of the chloride to be stabilized at 1-6 ppm after the reactor is operated, and reducing the concentration of the chloride to 0.1-1 ppm, preferably to 0.2-0.5 ppm when the concentration of ethylene oxide at the outlet of the reactor reaches 0.5-3.0 mol%;
the silver catalyst comprises an alpha-alumina carrier and an active component silver loaded on the carrier; the alpha-alumina carrier contains zirconium element and chromium element, and the content of the zirconium element is 0.001-3.0 wt%, preferably 0.01-2.0 wt%, and more preferably 0.1-1.5 wt% based on the weight of the alpha-alumina carrier; the content of the chromium element is 0.001-3.0 wt%, preferably 0.01-2.0 wt%, and more preferably 0.05-1.0 wt%; the molar ratio of the zirconium element to the chromium element is 0.001 to 1000, preferably 0.01 to 100, and more preferably 0.5 to 10.
The invention makes the selectivity of the catalyst improved obviously in a short time by selecting the alumina carrier containing chromium and zirconium and combining with the adjustment of the chloride concentration in the reactor. Since the present invention is directed only to the adjustment of the above steps, other process conditions and materials involved in the process of the present invention may be routinely selected in the art.
Specifically, theStabilizing gases include, but are not limited to: nitrogen, argon, helium, or mixtures thereof. The chloride refers to a chlorine-containing component as an inhibitor, and the chlorine-containing component can be C 1 -C 8 At least one of the chlorinated hydrocarbons, including but not limited to: methyl chloride, methylene chloride, ethyl chloride, ethylene dichloride, vinyl chloride, ethylene dichloride, or mixtures thereof.
According to the method of the invention, the alpha-alumina carrier can be used as long as the alpha-alumina carrier contains the zirconium element and the chromium element in the content, other components contained in the alpha-alumina carrier can be conventional components in the field, and the preparation method can also be conventional methods in the field.
According to a specific embodiment of the present invention, the α -alumina support is prepared by a method comprising the steps of:
step S1, obtaining a mixture comprising:
a component a: a1 2 O 3 A raw material such as alumina trihydrate;
and (b) component b: a binder;
and (b) component c: a zirconium compound;
and (b) a component d: a chromium compound;
and (e) a component e: optionally water;
and step S2, kneading the mixture obtained in the step S1 uniformly, extruding and molding, drying and roasting to obtain the alpha-alumina carrier.
In the present invention, the content of each component and each process step can be selected conventionally in the art.
Specifically, according to a preferred embodiment of the present invention, the content of the component a is 5 to 90wt%, preferably 25 to 80wt%, based on the total weight of the components a to d; the content of the component b is 5-85 wt%, preferably 15-60 wt%.
In the present invention, the specific selection of the precursor compounds of the zirconium element and the chromium element, i.e., the zirconium compound and the chromium compound in the catalyst support is not particularly limited.
Preferably, the zirconium compound is selected from one or more of zirconia, zirconium hydroxide, zirconium silicate, zirconium nitrate, zirconium sulfate and zirconium carbonate.
Preferably, the chromium compound is selected from one or more of chromium oxide, halide, hydroxide, nitrate, chromate and dichromate, further preferably from one or more of chromium oxide, chromium nitrate and potassium dichromate.
In the invention, the binder can be an aluminum sol which can be wholly or partially prepared by pseudo-monohydrate A1 2 O 3 And acid in a conventional ratio, for example, 1:0.5 to 1.5 by weight. The acid can be one or more of nitric acid, sulfuric acid, oxalic acid, hydrochloric acid and acetic acid, the acid is preferably an aqueous acid solution, and the volume ratio of the acid to the water is more preferably 1: 1.25-10, and more preferably 1: 2-4.
In the preparation of the catalyst carrier of the present invention, water as component e may be optionally added as required. Generally, when the adhesive is applied as pseudo-water A1 2 O 3 And the acid in the form of an aqueous solution, no additional water may be added to the system.
The present invention is not particularly limited with respect to the specific conditions of step S2, and according to one embodiment of the present invention, the mixture obtained in step S1 is poured into a kneader and kneaded into an extrudable paste. And finally, filling the paste into a strip extruding machine, extruding and molding, and drying at 80-120 ℃ to reduce the free water content to below 10% by weight. And (3) placing the dried formed body into a high-temperature kiln, and roasting at 1100-1500 ℃ to obtain the catalyst carrier.
The silver catalyst of the present invention can achieve the desired effects as long as it has the above-described characteristics of the carrier. The other components contained in the silver catalyst may be various components conventional in the art, including but not limited to: a silver-containing compound, an alkali metal promoter, optionally a rhenium promoter and/or a co-promoter therefor. The method for preparing the silver catalyst is not particularly limited in the present invention. For example by impregnating the above alumina support with a solution of a silver-containing compound, an organic amine, an alkali metal promoter and optionally a rhenium promoter.
According to one embodiment of the present invention, the silver catalyst is prepared by a method comprising the steps of:
dissolving a silver-containing compound, an alkali metal assistant and an optional rhenium assistant and/or a synergistic assistant thereof in an amine-containing solution and/or ammonia water to prepare a silver-ammonia solution;
and step II, putting the alpha-alumina carrier into the silver-ammonia solution obtained in the step I for soaking, leaching, drying and roasting to obtain the silver catalyst.
According to a more specific embodiment of the present invention, the silver catalyst is prepared by a method comprising the steps of: firstly, silver nitrate aqueous solution reacts with ammonium oxalate or oxalic acid aqueous solution to precipitate silver oxalate precipitate, the precipitate is washed by deionized water after filtration until no nitrate ions exist, and then the silver oxalate is dissolved in amine-containing solution (such as aqueous solution of organic amine or mixture thereof such as pyridine, butylamine, ethylenediamine, 1, 3-propanediamine, ethanolamine and the like) or ammonia water, and an auxiliary agent is added to prepare silver ammonia impregnation solution. Then, the alumina carrier is impregnated with the obtained impregnation solution, drained, calcined in air flow or nitrogen-oxygen mixed gas with oxygen content not more than 21 percent, and thermally decomposed. Silver oxide can also be used to replace silver nitrate, and silver oxalate can also be directly complexed with organic amine without leaching, and then the carrier is impregnated.
The present invention is not particularly limited with respect to the specific selection of the above-mentioned components in the silver catalyst.
Preferably, the silver-containing compound is a silver-containing organic compound and/or inorganic compound, more preferably an organic acid salt and/or inorganic acid salt of silver, and particularly preferably silver nitrate and/or silver oxalate; the silver-containing compound is added in an amount such that the content of silver in the silver catalyst is 2 to 39 wt%, preferably 10 to 35 wt%, based on the total weight of the silver catalyst.
Preferably, the alkali metal promoter is a compound containing at least one of lithium, sodium, potassium, rubidium and cesium, and the addition amount of the alkali metal promoter is such that the content of the alkali metal in the silver catalyst is 1 to 2000ppm, preferably 5 to 1500ppm, based on the total weight of the silver catalyst.
Preferably, the rhenium assistant is selected from one or more of rhenium oxide, perrhenic acid, cesium perrhenate, methyl rhenium trioxide (VII) and ammonium perrhenate, and the addition amount of the rhenium assistant is that the content of rhenium metal in the silver catalyst is 0-2000 ppm, preferably 100-1000 ppm, based on the total weight of the silver catalyst.
The conditions of the steps in the catalyst preparation process are not particularly limited in the present invention.
According to the invention, preferably, the calcination is carried out in air or a nitrogen-oxygen mixture having an oxygen content of not more than 21%. The roasting temperature is controlled to be 180-700 ℃, the roasting temperature is preferably 200-500 ℃, and the roasting time is 1-120 minutes, preferably 1.5-30 minutes.
In addition to the above promoters, other promoters may be added, such as rhenium co-promoters (chromium, molybdenum, tungsten, etc.), to further improve the activity, selectivity, and stability of the resulting silver catalyst.
In the preparation of the catalyst of the present invention, the above-mentioned various assistants may be applied to the carrier before, simultaneously with or after impregnation of the silver, or may be impregnated on the carrier after the reduction of the silver compound.
Additional features and advantages of the invention will be set forth in the detailed description which follows.
Detailed Description
The following describes the embodiments of the present invention in detail. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
Determination of catalyst Performance:
various silver catalysts of the present invention were tested for activity and selectivity using a laboratory microreactor evaluation unit. The reactor used in the microreactor evaluation means was a stainless steel reaction tube having an inner diameter of 4mm, which was placed in a heating mantle. The filling volume of the catalyst is 1ml, and the lower part of the catalyst is provided with inert filler, so that a catalyst bed layer is positioned in a constant temperature area of the heating sleeve.
The measurement conditions for the selectivity employed in the present invention are shown in Table 1:
TABLE 1 reaction measurement conditions of the catalysts
Figure BDA0002106834440000071
When the reaction conditions were stable and reached as described above, the reactor inlet and outlet gas compositions were continuously measured. The measurement results were corrected for volume shrinkage and the selectivity was calculated according to the following formula:
Figure BDA0002106834440000072
where Δ EO is the difference in ethylene oxide concentration between the reactor outlet gas and the inlet gas, Δ CO 2 The carbon dioxide concentration difference between the outlet gas and the inlet gas of the reactor is determined, and the average of more than 10 groups of test data is taken as the test result of the day.
The present invention is further illustrated by the following examples, but the scope of the present invention is not limited to these examples.
Support preparation comparative example 1
498g of trihydrate alpha-A1 2 O 3 102g pseudo-monohydrate A1 2 O 3 Put into a blender to be mixed uniformly, and then poured into a kneader. 0.12 l of dilute aqueous nitric acid (1: 3 by volume) was poured into a kneader and kneaded into an extrudable paste. And finally, filling the paste into a strip extruding machine, extruding and molding into a columnar object with the diameter of 8.0mm and the length of 6.0mm, and drying for more than 2 hours at the temperature of 80-120 ℃ to reduce the free water content to be less than 10 percent by weight. The dried column was placed in a high temperature kiln and allowed to warm from room temperature to 1360 ℃ over 36 hours, then held at constant temperature for 2 hours to give the product as a white solid, i.e., support DC1, which was analyzed by XRD and was found to be alpha-A1 2 O 3 。
Support preparation example 1
498g of alpha-A1 trihydrate 2 O 3 102g pseudo-monohydrate A1 2 O 3 5g of dioxideThe zirconium is put into a blender and mixed uniformly, and then poured into a kneader. 2.4 g of chromium nitrate nonahydrate were dissolved completely in 0.12 l of dilute aqueous nitric acid (nitric acid: water: 1: 3 by volume), and then the mixture was also poured into a kneader and kneaded into an extrudable paste. And finally, filling the paste into a strip extruding machine, extruding and molding the paste into a columnar object with the diameter of 8.0mm and the length of 6.0mm, and drying the columnar object for more than 2 hours at the temperature of 80-120 ℃ to reduce the free water content of the columnar object to be less than 10 percent by weight. The dried column was placed in a high temperature kiln and allowed to warm from room temperature to 1360 ℃ over a period of 36 hours and then held at that temperature for 2 hours to give the product as a pale red solid, Carrier C1, which was identified as alpha-A1 by XRD analysis 2 O 3 Based on the weight of the carrier, the content of the zirconium element is 0.8 wt%, and the content of the chromium element is 0.07 wt%.
Support preparation example 2
498g of trihydrate alpha-A1 2 O 3 102g pseudo-monohydrate A1 2 O 3 3g of zirconium dioxide are mixed in a blender until homogeneous, and then poured into a kneader. 4.8 g of chromium nitrate nonahydrate were dissolved completely in 0.12 l of dilute aqueous nitric acid (nitric acid: water 1: 3 by volume), and the mixture was also poured into a kneader and kneaded into an extrudable paste. And finally, filling the paste into a strip extruding machine, extruding and molding the paste into a columnar object with the diameter of 8.0mm and the length of 6.0mm, and drying the columnar object for more than 2 hours at the temperature of 80-120 ℃ to reduce the free water content of the columnar object to be less than 10 percent by weight. The dried column was placed in a high temperature kiln and allowed to warm from room temperature to 1360 ℃ over 36 hours and then held at constant temperature for 2 hours to give the product as a pale red solid, support C2, which was identified as alpha-A1 by XRD analysis 2 O 3 Based on the weight of the carrier, the content of zirconium element is 0.5 wt%, and the content of chromium element is 0.14 wt%.
Support preparation example 3
498g of trihydrate alpha-A1 2 O 3 102g of pseudo-Water A1 2 O 3 4 g of zirconium dioxide are mixed in a blender until homogeneous and then poured into a kneader. 3.6 g of chromium nitrate nonahydrate was dissolved in 0.12 l of dilute aqueous nitric acid (nitric acid:water 1: 3, volume ratio) is completely dissolved, and then the mixture is poured into a kneader and kneaded into paste which can be extruded and molded. And finally, filling the paste into a strip extruding machine, extruding and molding the paste into a columnar object with the diameter of 8.0mm and the length of 6.0mm, and drying the columnar object for more than 2 hours at the temperature of 80-120 ℃ to reduce the free water content of the columnar object to be less than 10 percent by weight. The dried column was placed in a high temperature kiln and allowed to warm from room temperature to 1360 ℃ over a period of 36 hours and then held at that temperature for 2 hours to give the product as a pale red solid, Carrier C3, which was identified as alpha-A1 by XRD analysis 2 O 3 Based on the weight of the carrier, the content of zirconium element is 0.6 wt%, and the content of chromium element is 0.11 wt%.
Comparative catalyst preparation example 1 and catalyst preparation examples 1 to 3
In order to examine the catalytic performance of the carriers in the carrier preparation example and the carrier preparation comparative example, silver catalysts were prepared using the same method. The specific preparation method of the silver catalyst comprises the following steps: in a stirred glass beaker, 9.0g of ethylenediamine and 25.2g of deionized water were added to obtain a mixed solution. 15.0g of silver oxalate was slowly added to the mixture with continuous stirring, and the temperature was kept at 30 ℃ or lower to completely dissolve the silver oxalate. Then, 0.35ml of an aqueous cesium sulfate solution (concentration: 0.0503g/ml, in terms of cesium atom weight) and 0.46ml of an aqueous ammonium perrhenate solution (concentration: 0.0162g/ml, in terms of rhenium atom weight) were added in this order, and mixed uniformly to prepare 50g of an impregnation solution for use.
15g of each of the carrier C1-C3 prepared in the carrier preparation example and the carrier DC1 prepared in the carrier preparation comparative example were separately taken and placed in a glass vessel capable of being evacuated, and the above impregnation solution was added to completely immerse the carriers. After applying a vacuum above 10mmHg for about 15 minutes, the excess solution is leached away. Finally, the impregnated support samples were placed in an air stream at 350 ℃ and heated for about 3 minutes to prepare silver catalysts DCat-1 (corresponding to comparative support preparation) and Cat-1, Cat-2 and Cat-3 (corresponding to support preparation examples 1 to 3, respectively).
Example 1
The process conditions of the reactor are as follows: the concentration of dichloroethane stabilized at 3ppm after the reactor had been operated, and was reduced to 0.3ppm when the concentration of ethylene oxide at the reactor outlet reached 1.5 mol%. The performance of each catalyst sample was measured under the aforementioned process conditions using a microreactor evaluation apparatus, and the evaluation results are shown in Table 2.
TABLE 2 measurement results of catalyst Properties
Figure BDA0002106834440000101
As can be seen from table 2, the selectivity of the catalyst can be improved by adjusting the concentration of dichloroethane, and the selectivity of the silver catalyst prepared by using the carrier to which the Cr compound and the Zr compound are simultaneously added is significantly higher after adjusting the concentration of chloride, compared to the comparative example in which the Cr compound and the Zr compound are not added to the carrier.
Example 2
The process conditions of the reactor are as follows: the concentration of dichloroethane stabilized at 3ppm after the reactor had been operated, and was reduced to 0.8ppm when the concentration of ethylene oxide at the reactor outlet reached 1.5 mol%. The performance of each catalyst sample was measured under the same process conditions as in example 1 using a microreactor evaluation apparatus, and the evaluation results are shown in Table 3.
TABLE 3 measurement results of catalyst Properties
Figure BDA0002106834440000111
As can be seen by comparing the data in tables 2 and 3, adjusting the concentration of dichloroethane to the preferred range further enhances the selectivity gain.
Example 3
The process conditions of the reactor are as follows: the concentration of dichloroethane stabilized at 2ppm after the reactor had been operated, and was reduced to 0.3ppm when the concentration of ethylene oxide at the reactor outlet reached 1.0 mol%. The performance of the catalyst sample Cat-1 was measured under the same process conditions as in example 1 using a microreactor evaluation apparatus, and the evaluation results are shown in Table 4.
Example 4
The process conditions of the reactor are as follows: the concentration of dichloroethane stabilized at 4ppm after the reactor was operated, and when the concentration of ethylene oxide at the outlet of the reactor reached 2.0 mol%, the concentration of dichloroethane was reduced to 0.3 ppm. The performance of the catalyst sample Cat-1 was measured under the same process conditions as in example 1 using a microreactor evaluation apparatus, and the evaluation results are shown in Table 4.
TABLE 4 measurement results of catalyst Properties
Figure BDA0002106834440000121
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.
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and these ranges or values should be understood to encompass values close to these ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

Claims (25)

1. A method for preparing ethylene oxide by ethylene epoxidation comprises the following steps: mixing a silver catalyst, ethylene, oxygen, a stabilizing gas and chloride in a reactor to perform ethylene epoxidation, controlling the concentration of the chloride to be stabilized at 1-6 ppm after the reactor is operated, and reducing the concentration of the chloride to 0.1-1 ppm when the concentration of ethylene oxide at the outlet of the reactor reaches 0.5-3.0 mol%;
the silver catalyst comprises an alpha-alumina carrier and an active component silver loaded on the carrier; the alpha-alumina carrier contains zirconium and chromium, and the content of the zirconium is 0.001-3.0 wt% based on the weight of the alpha-alumina carrier; the content of the chromium element is 0.001-3.0 wt%; the molar ratio of the zirconium element to the chromium element is 0.001-1000.
2. The method of claim 1, wherein the chloride concentration is reduced to 0.2-0.5 ppm.
3. The method according to claim 1, wherein the content of the zirconium element is 0.01 to 2.0 wt%.
4. The method of claim 3, wherein the zirconium is present in an amount of 0.1 to 1.5 wt%.
5. The method according to claim 1, wherein the content of the chromium element is 0.01 to 2.0 wt%.
6. The method according to claim 5, wherein the content of the chromium element is 0.05 to 1.0 wt%.
7. The method according to claim 1, wherein the molar ratio of the zirconium element to the chromium element is 0.01 to 100.
8. The method according to claim 7, wherein the molar ratio of the zirconium element to the chromium element is 0.5 to 10.
9. The method of claim 1 wherein said α -alumina support is prepared by a method comprising the steps of:
step S1, obtaining a mixture comprising:
a component a: a1 2 O 3 Raw materials;
and (b) component b: a binder;
and (b) component c: a zirconium compound;
a component d: a chromium compound;
and (e) component: optionally water;
and S2, kneading the mixture obtained in the step S1 uniformly, extruding and molding, drying and roasting to obtain the alpha-alumina carrier.
10. The method of claim 9, wherein component a is present in an amount of 5 to 90wt%, based on the total weight of components a to d; the content of the component b is 5-85 wt%.
11. The method of claim 10, wherein component a is present in an amount of 25 to 80 wt%.
12. The method of claim 10, wherein the content of component b is 15 to 60 wt%.
13. The method of any one of claims 9-12, wherein the zirconium compound is selected from one or more of zirconium oxide, zirconium hydroxide, zirconium silicate, zirconium nitrate, zirconium sulfate, and zirconium carbonate.
14. The method of any one of claims 9-12, wherein the chromium compound is selected from one or more of an oxide, halide, hydroxide, nitrate, chromate, and dichromate of chromium.
15. The method of claim 14, wherein the chromium compound is selected from one or more of chromium oxide, chromium nitrate, and potassium dichromate.
16. The method of any one of claims 9-12, wherein the binder is an aluminum sol, the aluminum sol being wholly or partially treated with pseudo-monohydrate a1 2 O 3 And in the form of an acid.
17. The method of claim 1, wherein the silver catalyst is prepared by a process comprising:
dissolving a silver-containing compound, an alkali metal assistant and an optional rhenium assistant and/or a synergistic assistant thereof in an amine-containing solution and/or ammonia water to prepare a silver-ammonia solution;
and step II, soaking the alpha-alumina carrier in the silver-ammonia solution obtained in the step I, leaching, drying and roasting to obtain the silver catalyst.
18. The method of claim 17, wherein the silver-containing compound is a silver-containing organic compound and/or an inorganic compound; the silver-containing compound is added in an amount such that the content of silver in the silver catalyst is 2 to 39 wt%, based on the total weight of the silver catalyst.
19. The method of claim 18, wherein the silver-containing compound is an organic acid salt and/or an inorganic acid salt of silver.
20. The method of claim 19, wherein the silver-containing compound is silver nitrate and/or silver oxalate.
21. The method of claim 18, wherein the silver-containing compound is added in an amount such that the content of silver in the silver catalyst is 10 to 35 wt%.
22. The method of claim 17, wherein the alkali metal promoter is a compound containing at least one of lithium, sodium, potassium, rubidium, and cesium, and is added in an amount such that the alkali metal is present in the silver catalyst in an amount of 1 to 2000ppm based on the total weight of the silver catalyst.
23. The method of claim 22, wherein the alkali metal promoter is added in an amount such that the alkali metal is present in the silver catalyst in an amount of 5 to 1500 ppm.
24. The method as claimed in claim 17, wherein the rhenium promoter is selected from one or more of rhenium oxide, perrhenic acid, cesium perrhenate, methyl rhenium trioxide and ammonium perrhenate, and is added in an amount such that the rhenium metal content in the silver catalyst is 0 to 2000ppm, based on the total weight of the silver catalyst.
25. The process of claim 24, wherein the rhenium promoter is added in an amount such that the rhenium metal content in the silver catalyst is from 100 to 1000 ppm.
CN201910555773.9A 2019-06-25 2019-06-25 Method for preparing ethylene oxide by ethylene epoxidation Active CN112125869B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910555773.9A CN112125869B (en) 2019-06-25 2019-06-25 Method for preparing ethylene oxide by ethylene epoxidation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910555773.9A CN112125869B (en) 2019-06-25 2019-06-25 Method for preparing ethylene oxide by ethylene epoxidation

Publications (2)

Publication Number Publication Date
CN112125869A CN112125869A (en) 2020-12-25
CN112125869B true CN112125869B (en) 2022-08-19

Family

ID=73849451

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910555773.9A Active CN112125869B (en) 2019-06-25 2019-06-25 Method for preparing ethylene oxide by ethylene epoxidation

Country Status (1)

Country Link
CN (1) CN112125869B (en)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103261182A (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
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
CN104069894A (en) * 2013-03-27 2014-10-01 中国石油化工股份有限公司 Method of preparing alpha-alumina carrier used for silver catalyst, the carrier and the catalyst
CN106955694A (en) * 2016-01-08 2017-07-18 中国石油化工股份有限公司 A kind of alpha-alumina supports, silver catalyst prepared therefrom and its application
CN109225180A (en) * 2017-07-10 2019-01-18 中国石油化工股份有限公司 The method that alumina support and preparation method thereof, epoxidation of ethylene silver catalyst and ethylene epoxidizing prepare ethylene oxide

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103261182A (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
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
CN104069894A (en) * 2013-03-27 2014-10-01 中国石油化工股份有限公司 Method of preparing alpha-alumina carrier used for silver catalyst, the carrier and the catalyst
CN106955694A (en) * 2016-01-08 2017-07-18 中国石油化工股份有限公司 A kind of alpha-alumina supports, silver catalyst prepared therefrom and its application
CN109225180A (en) * 2017-07-10 2019-01-18 中国石油化工股份有限公司 The method that alumina support and preparation method thereof, epoxidation of ethylene silver catalyst and ethylene epoxidizing prepare ethylene oxide

Also Published As

Publication number Publication date
CN112125869A (en) 2020-12-25

Similar Documents

Publication Publication Date Title
KR101698945B1 (en) An alumina support, a preparation method for the same, and a silver catalyst prepared from the same, and use thereof
KR101905604B1 (en) An alumina support for silver catalyst, its preparation and its use
KR101844036B1 (en) A carrier for silver catalyst, its preparation, a silver catalyst made from the same and its use
WO2005039757A1 (en) Catalysts having enhanced stability, efficiency and/or activity for alkylene oxide production
KR20080096678A (en) A carrier for olefin oxidation catalyst, preparation method and application thereof
CN110038543B (en) Alpha-alumina carrier of silver catalyst for ethylene epoxidation, silver catalyst and method for producing ethylene oxide by ethylene epoxidation
CN108283943B (en) Alumina carrier and preparation method thereof, silver catalyst for ethylene epoxidation reaction and method for preparing ethylene oxide by ethylene epoxidation
CN102145306A (en) Method for adjusting properties of alumina carrier by selecting hydrated alumina with different grain size, carrier obtained by method and application
CN109225180A (en) The method that alumina support and preparation method thereof, epoxidation of ethylene silver catalyst and ethylene epoxidizing prepare ethylene oxide
CN108686712B (en) Modified alpha-alumina carrier and preparation method thereof, silver catalyst and application
CN105618047A (en) Method for preparation of silver catalyst for epoxidation and application thereof
CN112892529B (en) Silver catalyst for preparing ethylene oxide and preparation method and application thereof
CN112125869B (en) Method for preparing ethylene oxide by ethylene epoxidation
CN115069245B (en) Silver catalyst for producing ethylene oxide by ethylene oxidation and preparation method and application thereof
CN112295561B (en) Epoxidation catalyst and preparation method thereof
CN112121780B (en) Alpha-alumina carrier, preparation method thereof, silver catalyst and application
CN115487809A (en) Preparation method of silver catalyst for producing ethylene oxide by ethylene oxidation, silver catalyst and application
CN107442109B (en) Silver catalyst carrier, preparation method and application thereof
CN115364854B (en) Preparation method of silver catalyst for ethylene oxide production by ethylene oxidation, silver catalyst and application
CN111437888A (en) α -alumina carrier, silver catalyst for ethylene epoxidation and application
CN115364853B (en) Silver catalyst for producing ethylene oxide by ethylene oxidation and preparation method and application thereof
CN111437816A (en) Supported silver catalyst and preparation method and application thereof
CN114426527B (en) Silver catalyst carrier for ethylene oxide, preparation method and silver catalyst and application
CN110354841A (en) Silver catalyst alpha-alumina supports and preparation method thereof and ethylene epoxidizing silver catalyst and application
CN109107553B (en) Alumina carrier and preparation method thereof, silver catalyst and application

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant