CN117732462A - Carrier for preparing silver catalyst, preparation method of carrier, silver catalyst, preparation method of silver catalyst and application of silver catalyst - Google Patents

Abstract

The invention belongs to the field of silver catalysts, and particularly relates to a carrier for preparing a silver catalyst, a preparation method of the carrier, the silver catalyst, a preparation method of the silver catalyst and application of the silver catalyst. The carrier comprises: alpha-Al ₂ O ₃ Carrier, supported on alpha-Al ₂ O ₃ Zirconium oxide and tungsten oxide with hollow configuration on the surface of the carrier; relative to the alpha-Al ₂ O ₃ The carrier comprises the following components in percentage by weight: 0.02 to 4.00 weight percent of zirconia with hollow structure and 0.002 to 0.500 weight percent of tungsten oxide. The invention is realized by the method that the catalyst is prepared by the following steps of ₂ O ₃ The surface of the carrier is subjected to acid etching to enable the surface to be roughened, and orderly loading of hollow zirconium oxide and tungsten oxide is sequentially carried outAnd then roasting and solidifying at high temperature, the silver catalyst prepared from the silver catalyst has higher selectivity and reactivity, and is particularly suitable for the reaction of ethylene oxidation to produce ethylene oxide.

Description

Carrier for preparing silver catalyst and preparation method thereof, silver catalyst and preparation thereof Methods and applications

Technical field

The present invention belongs to the field of silver catalysts, and specifically relates to carriers used to prepare silver catalysts and their preparation methods, silver catalysts and their preparation methods and applications.

Background technique

Under the action of silver catalyst, ethylene oxidation mainly produces ethylene oxide, and side reactions occur to produce carbon dioxide and water. Among them, activity, selectivity and stability are the main performance indicators of silver catalyst. The so-called activity refers to the reaction temperature required when the ethylene oxide production process reaches a certain reaction load. The lower the reaction temperature, the higher the activity of the catalyst. The so-called selectivity refers to the ratio of the number of moles of ethylene converted into ethylene oxide during the reaction to the total number of reaction moles of ethylene. The so-called stability is expressed as the decline rate of activity and selectivity. The smaller the decline rate, the better the stability of the catalyst. The use of silver catalysts with high activity, high selectivity and good stability in the process of ethylene oxidation to produce ethylene oxide can greatly improve economic benefits. Therefore, manufacturing silver catalysts with high activity, high selectivity and good stability is an important step in silver catalyst research. main direction. In addition to the composition and preparation method of the catalyst, the performance of the silver catalyst is also closely related to the performance and preparation method of the carrier used in the catalyst.

The preparation method of silver catalysts in the prior art includes two processes: preparation of a porous carrier (such as alumina) and application of active components and auxiliaries to the carrier. In the preparation process of silver catalyst, for the carrier with α-Al ₂ O ₃ as the main component, suitable specific surface and pore structure are needed. On the one hand, it is necessary to provide enough space for the ethylene epoxidation reaction. Diffusing the heat of reaction also facilitates the timely desorption of the reaction product ethylene oxide and avoids deep oxidation to generate carbon dioxide as a by-product. German patent WO2021260138A1 provides a shaped catalyst body for the gas phase oxidation of ethylene to produce ethylene oxide, which has a BET surface area of 2-20 m ² /g and contains silver and rhenium promoters deposited on a porous alumina catalyst support, Characterized by a support having a calcination history of at least 1460°C, the catalyst support has a high surface area and a small amount of ethylene oxide isomerization and/or decomposition activity. Chinese patent CN1009437B uses a suitable proportion of alumina trihydrate to prepare an alumina carrier with a specific surface of 0.2 to 2m ² /g and a pore volume greater than 0.5mL/g. The pores with a pore radius greater than 30 μm account for less than 25%. In the ethylene epoxidation reaction, the selectivity can reach 83~84%.

Adding other components to the alumina carrier to improve the carrier and improve the performance of the silver catalyst is also an important research direction. In addition, the performance of silver catalysts can also be improved by chemically treating the alumina support. German patent WO2021260185A1 provides a sheet catalyst carrier characterized by an α-alumina content of at least 85 wt.%, a pore volume measured by mercury porosimetry of at least 0.40 mL/g, and a BET surface area of 0.5-5.0 m ² / g. The sheet-shaped catalyst carrier is an α-alumina catalyst carrier, which has high geometric accuracy and displays a high total pore volume, thereby allowing impregnation with a large amount of silver while displaying a large enough surface area to provide catalytic Optimum dispersion of active substances, especially metallic substances. European patent EP0150238B1 uses a small amount of barium aluminate or barium silicate binder in the manufacturing process of high-purity, low-surface alumina carriers, claiming to improve the crushing strength and anti-wear properties of the carrier. The specific surface of the carrier manufactured by this patent is less than 0.3m ² /g, the activity and selectivity of the prepared catalyst are relatively low. The alumina carrier used in US4740493A, US4829043A and EP0501317A1 contains a certain amount of Ca, Al, K, and Na soluble salts, which are claimed to reduce the rate of decline in catalyst selectivity during use. US5384302A claims that reducing the Na, K, Ca, and Al ion content in the carrier by pretreating α-Al ₂ O ₃ improves the crushing strength and wear resistance of the carrier. Korean patent KR102258044B1 is a preparation method for a catalyst that generates high-yield ethylene oxide from ethylene by adding polyvinyl pyrrolidone to adjust the metal crystal size. EP0712334B1 prepares a silver catalyst by loading an effective amount of silver, an auxiliary amount of alkali metal, an auxiliary amount of magnesium and an auxiliary amount of rhenium on a carrier containing at least 85% alumina and 0.001-2% magnesium in the form of oxide. Improved catalyst stability. US5100859A, US5145824A, EP0900126B1, US5801259A, US5733842A add alkaline earth metals, silicon, and zirconium to α-Al ₂ O ₃ to make a carrier, and then impregnate silver, alkali metal additives, rhenium additives and their assistants to make a silver catalyst. The patent points out that alkaline earth metals Metals are preferably calcium, strontium and barium salts used together with zirconium compounds, and the effect of adding both on catalyst performance is unknown. US5739075A pre-deposits an additive amount of rare earth metal and another additive amount of metal salt (alkaline earth metal or Group VIII transition metal) on the surface of an alumina carrier, and then performs a calcination treatment, and finally the treated carrier is made into a silver catalyst , the evaluation results show that the selectivity decrease rate of the catalyst is smaller than that of the catalyst sample without pre-deposition treatment. CN1511632A found that a compound of heavy alkaline earth metal is added to the alumina raw material to make a carrier, and a solution prepared by impregnating a silver compound, an organic amine and a specific auxiliary, and heat-treated in an oxygen-containing mixed gas is used to prepare a silver catalyst for ethylene oxidation. The activity and selectivity in the reaction have been improved.

Although the above-mentioned patent documents use various methods to improve the alumina carrier and bring varying degrees of improvement to the activity, stability and selectivity of the catalyst, with the large-scale industrial application of Re-containing high-selectivity silver catalysts, the catalyst Performance requirements are also constantly increasing, so there is a need to continuously improve the performance of silver catalysts.

Contents of the invention

In view of the above-mentioned state of the art, the inventor of the present invention has conducted extensive and in-depth research in the field of silver catalysts. As a result, he found that while acid etching is performed on the surface of the α-Al ₂ O ₃ carrier, by impregnating zirconium salt and template agent Drying, loading hollow-configured zirconia on the surface of alumina, then impregnating tungstic acid and/or tungstate solution and drying, then roasting at high temperature, and finally impregnating silver ammonia solution and drying, can significantly improve the silver catalyst made from it selectivity and reactivity.

A first aspect of the present invention provides a carrier for preparing a silver catalyst, which carrier includes:

α-Al ₂ O ₃ carrier, hollow-configured zirconia and tungsten oxide loaded on the surface of the α-Al ₂ O ₃ carrier;

Relative to the α-Al ₂ O ₃ carrier, the content of each component is:

The hollow configuration of zirconium oxide is 0.02-4.00wt%, and the tungsten oxide is 0.002-0.500wt%.

A second aspect of the present invention provides a method for preparing a carrier for preparing a silver catalyst. The preparation method includes:

(1) Dip α-A1 ₂ O ₃ in the first solution, then solid-liquid separation and drying;

(2) Impregnating the carrier obtained in step (1) in the second solution, and then solid-liquid separation, drying, and roasting to obtain the carrier for preparing the silver catalyst;

The first solution is a mixed solution of acid, zirconium salt and template agent;

The second solution is tungstic acid and/or tungstate solution, and the solvent of the tungstate solution is selected from at least one of water, ammonia and amine compounds.

A third aspect of the present invention provides a carrier prepared by the above preparation method.

A fourth aspect of the present invention provides a silver catalyst, which includes:

Carrier, silver, alkali metal additives, optional rhenium additives, and optional rhenium additive co-additives loaded on the surface of the carrier;

The carrier is the above-mentioned carrier used to prepare the silver catalyst, or the carrier prepared by the above-mentioned method.

The fifth aspect of the present invention provides a preparation method of the above-mentioned silver catalyst, which preparation method includes:

The carrier is immersed in a silver ammonia solution, followed by solid-liquid separation and drying to obtain the silver catalyst.

The sixth aspect of the present invention provides the application of the above-mentioned silver catalyst in the reaction of ethylene oxidation to produce ethylene oxide.

Compared with the prior art, the present invention has the following advantages:

While the α-Al ₂ O ₃ carrier surface is acid etched, hollow-configured zirconium oxide is supported on the alumina surface by impregnating zirconium salt and template agent and drying, and then impregnating tungstic acid and/or tungstate solution and drying. Drying, then roasting at high temperature, and finally immersing in silver ammonia solution and drying can significantly improve the selectivity and reactivity of the silver catalyst made from it, and is especially suitable for the reaction of ethylene oxidation to produce ethylene oxide.

Other features and advantages of the present invention will be described in detail in the following detailed description.

Detailed ways

Specific embodiments of the present invention will be described in detail below. It should be understood that the specific embodiments described here are only used to illustrate and explain the present invention, and are not intended to limit the present invention.

A first aspect of the present invention provides a carrier for preparing a silver catalyst, which carrier includes:

α-Al ₂ O ₃ carrier, hollow-configured zirconia and tungsten oxide loaded on the surface of the α-Al ₂ O ₃ carrier;

Relative to the α-Al ₂ O ₃ carrier, the content of each component is:

The hollow configuration of zirconium oxide is 0.02-4.00wt%, and the tungsten oxide is 0.002-0.500wt%.

As a preferred embodiment, relative to the α-Al ₂ O ₃ carrier, the contents of each component are: 0.05 to 1.00 wt% of hollow-configured zirconium oxide and 0.005 to 0.100 wt% of tungsten oxide.

As a preferred solution, the α-Al ₂ O ₃ carrier includes at least one of the following characteristics:

α-A1 ₂ O ₃ content ≥90%;

The crushing strength is 20~200N/grain;

The specific surface area is 0.2~3.0m ² /g;

Water absorption rate ≥30%;

The pore volume is 0.30~0.85mL/g.

A second aspect of the present invention provides a method for preparing a carrier for preparing a silver catalyst. The preparation method includes:

(1) Dip α-A1 ₂ O ₃ in the first solution, then solid-liquid separation and drying;

(2) Impregnating the carrier obtained in step (1) in the second solution, and then solid-liquid separation, drying, and roasting to obtain the carrier for preparing the silver catalyst;

The first solution is a mixed solution of acid, zirconium salt and template agent;

The second solution is tungstic acid and/or tungstate solution, and the solvent of the tungstate solution is selected from at least one of water, ammonia and amine compounds.

In the present invention, the surface of the carrier formed after etching the carrier with acid is rough.

In the present invention, the solid-liquid separation method in steps (1) and (2) can be leaching. The leaching process is preferably to reduce the excess impregnation liquid attached to the surface of the carrier as much as possible. While performing the leaching process, Remove excess dust from the alumina carrier.

As a preferred embodiment, in step (1), the immersion time is 10 to 300 minutes, and the immersion is performed under a pressure of less than 100 mmHg.

As a preferred embodiment, in step (2), the immersion time is 10 to 300 minutes, and the immersion is performed under a pressure of less than 100 mmHg.

As a preferred option, in step (1), drying is performed in the air or in a nitrogen-oxygen mixture with an oxygen content of no more than 21%; the drying temperature is 100-600°C, preferably 150-500°C; the drying time is 0.5 to 120 minutes, preferably 1 to 30 minutes.

As a preferred option, in step (2), drying is performed in the air or in a nitrogen-oxygen mixture with an oxygen content of no more than 21%; the drying temperature is 100-600°C, preferably 150-500°C; the drying time is 0.5 to 120 minutes, preferably 1 to 30 minutes.

As a preferred option, in step (2), roasting is carried out in air or in a nitrogen-oxygen mixture with an oxygen content of no more than 21%; the roasting temperature is 500-1400°C, preferably 700-1200°C; the roasting time is 5 to 240 minutes, preferably 10 to 120 minutes.

As a preferred embodiment, the acid is selected from at least one of sulfuric acid, nitric acid and oxalic acid.

As a preferred embodiment, the zirconium salt is selected from at least one selected from the group consisting of zirconium sulfate, zirconium nitrate and zirconium oxynitrate.

As a preferred embodiment, the template agent is selected from at least one of chitosan, polystyrene and glucosamine.

As a preferred solution, based on the total weight of the first solution, the content of the acid is 0.2-20.0wt%, the content of the zirconium salt is 0.05-10.00wt%, and the content of the template agent is 0.02-6.0wt %.

As a further preferred embodiment, based on the total weight of the first solution, the content of the acid is 1.0-15.0wt%, the content of the zirconium salt is 0.1-5.0wt%, and the content of the template agent is 0.05-15.0wt%. 3.0wt%.

As a preferred embodiment, the tungstate is ammonium tungstate and/or potassium tungstate.

As a preferred embodiment, based on the total weight of the second solution, the content of the tungstic acid and/or tungstate is 0.002 to 0.500 wt%.

As a further preferred embodiment, based on the total weight of the second solution, the content of the tungstic acid and/or tungstate is 0.01 to 0.20 wt%.

A third aspect of the present invention provides a carrier prepared by the above preparation method.

A fourth aspect of the present invention provides a silver catalyst, which includes:

Carrier, silver, alkali metal additives, optional rhenium additives, and optional rhenium additive co-additives loaded on the surface of the carrier;

The carrier is the above-mentioned carrier used to prepare the silver catalyst, or the carrier prepared by the above-mentioned method.

As a preferred option, relative to the silver catalyst, the content of each component is:

The atomic silver content is 2 to 39 wt%, the alkali metal additive is 1 to 2000 ppm, the rhenium additive is 0 to 2000 ppm, and the co-agent of the rhenium additive is 0 to 2000 ppm.

As a further preferred embodiment, relative to the silver catalyst, the content of each component is:

The atomic amount of silver is 10-35wt%, the alkali metal additive is 5-2000ppm, the rhenium atomic amount is 100-1000ppm of the rhenium additive, and the atomic amount of the co-agent of the rhenium additive is 100-1000ppm.

As a preferred embodiment, the alkali metal auxiliary agent is selected from at least one compound of each of lithium, sodium, potassium, rubidium and cesium. Preferably, the alkali metal additive is added in an amount such that the content of the alkali metal additive in the silver catalyst is 1 to 2000 ppm.

As a preferred embodiment, the rhenium auxiliary agent is selected from at least one of rhenium oxide, perrhenic acid, cesium perrhenate, methyl rhenium (VII) trioxide and ammonium perrhenate.

As a preferred embodiment, the co-agent of the rhenium additive is selected from at least one salt or acid containing manganese, chromium, sulfur, cobalt, molybdenum, and nickel.

The fifth aspect of the present invention provides a preparation method of the above-mentioned silver catalyst, which preparation method includes:

The carrier is immersed in a silver ammonia solution, followed by solid-liquid separation and drying to obtain the silver catalyst.

In the preparation method of the silver catalyst of the present invention, the solid-liquid separation method can be leaching. The leaching process is preferably to reduce the excess impregnation liquid attached to the surface of the carrier as much as possible. During the leaching process, excess impregnation liquid in the alumina carrier can be removed. of dust.

In the preparation method of the silver catalyst of the present invention, the impregnation can be carried out according to conventional methods in this field. The carrier is completely immersed in the silver ammonia solution and fully immersed. The impregnation time is preferably 10 to 300 minutes; the temperature of the immersion liquid is preferably maintained at 30°C. Below, prevent thermal decomposition of silver-containing compounds and other premature precipitation; the impregnation process can be accelerated by reducing the pressure to less than 100mmHg pressure, so that there are no small bubbles on the surface of the carrier and the inner and outer surfaces are fully infiltrated.

As a preferred solution, preferably, the impregnation time is 10 to 300 minutes, and the impregnation is performed under a pressure of less than 100 mmHg.

As a preferred option, drying is carried out in the air or in a nitrogen-oxygen mixture with an oxygen content of no more than 21%. The drying temperature is 100-600°C, more preferably 150-500°C; the drying time is 0.5-120 minutes. More preferably, it is 1 to 30 minutes.

As a preferred version, the silver ammonia solution includes silver-containing compounds, amine compounds, water, alkali metal auxiliaries, optional rhenium auxiliaries, optional rhenium auxiliaries co-agent; the total weight of the silver ammonia solution is As a standard, the content of the amine compound is 10 to 90 wt%.

As a further preferred embodiment, the silver-containing compound is selected from at least one selected from the group consisting of silver acetate, silver nitrate and silver oxalate. Preferably, the silver-containing compound is added in an amount such that the atomic content of silver in the silver catalyst is 2 to 39 wt%, preferably 10 to 35 wt%.

As a further preferred embodiment, the amine compound is at least one selected from ammonia water, ethylamine, n-propylamine, ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, N,N-dimethylformamide, ethanolamine and propanolamine.

The sixth aspect of the present invention provides the application of the above-mentioned silver catalyst in the reaction of ethylene oxidation to produce ethylene oxide.

The silver catalyst prepared by the invention has high selectivity and reaction activity, and can be used in the reaction of ethylene oxidation to produce ethylene oxide. Specifically, in the presence of the silver catalyst, a mixture of ethylene and oxygen and other gases is reacted in a fixed-bed microtubular reactor.

The present invention will be further described below with reference to examples, but the scope of the present invention is not limited to these examples.

Determination of catalyst performance:

Various silver catalysts of the present invention are tested for their initial performance and stability using a laboratory reactor (hereinafter referred to as "micro-reactor") evaluation device. The reactor used in the microreflector evaluation device is a stainless steel tube with an inner diameter of 4 mm, and the reactor is placed in a heating mantle. The filling volume of the catalyst is 1 mL, and there is an inert filler at the bottom so that the catalyst bed is located in the constant temperature zone of the heating jacket.

Determination of initial activity and selectivity:

The assay conditions for activity and selectivity used in the present invention are as follows:

The reaction gas composition (mol%) is shown in Table 1.

Table 1

Ethylene (C ₂ H ₄ ) 28±1 Oxygen (O ₂ ) 7.4±0.2 Carbon dioxide (CO ₂ ) <3 Stable Qi (N ₂ ) margin inhibitor dichloroethane Optimize adjustment reaction pressure 2.1MPa airspeed Adjustable between 3000-7000/h Reactor outlet EO concentration 1.5-2.8mol% space-time yield 88-385gEO/mLCat./h

When the above reaction conditions are reached, the gas composition at the inlet and outlet of the reactor is continuously measured. After the measurement results are corrected for volume shrinkage, the selectivity is calculated according to the following formula:

Among them, ΔEO is the difference in ethylene oxide concentration between the outlet gas and the inlet gas. The average of more than 10 sets of test data is taken as the test result of the day.

The activity of the catalyst is measured by the reaction temperature when a certain EO concentration is reached.

The element content in the present invention is measured by chemical analysis and XRF. The micromorphology of the catalyst and its support was characterized by SEM and TEM.

The α-alumina carriers used in Examples 1-9 and Comparative Example 1 are all made from the same carrier formula. For details, please refer to CN88100400.6, CN1634652A and US5063195, which will not be described in detail here. The α-alumina carrier has the following characteristics: α-A1 ₂ O ₃ content is 99.5%; crushing strength is 85N/grain; specific surface area is 1.13m ² /g; water absorption rate is 45%; pore volume is 0.47mL/ g.

Example 1

First, prepare 198 mL of 5wt% sulfuric acid aqueous solution in a glass beaker, then add 2g zirconium sulfate and 0.5g chitosan to the sulfuric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, and add the above immersion liquid to completely immerse the carrier. Evacuate to above 10 mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10wt% ammonia solution in a glass, then add 1.3g of ammonium tungstate (H ₂₆ N ₆ O ₄₀ W ₁₂ ) to the ammonia solution, and mix it evenly. Place the heated carrier impregnated with the dilute sulfuric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 1.

The contents of each component supported on the surface of Carrier Example 1 are: 0.22wt% of hollow-configured zirconium oxide and 0.026wt% of tungsten oxide.

Add 32.1g of ethylenediamine, 10.8g of ethanolamine and 179.8g of deionized water into a stirred glass beaker to obtain a mixed solution; slowly add 72.2g of silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring to completely dissolve the silver oxalate; then add 2.25mL of cesium nitrate aqueous solution (concentration of 0.03995g/mL, based on cesium atomic weight) and 2.78mL of ammonium perrhenate aqueous solution (concentration of 0.0162g/mL, based on rhenium atomic weight) in sequence, mix well to prepare 300g of impregnation solution for standby use.

Take 15 g of the carrier Example 1, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare Silver Catalyst Example 1.

Relative to Silver Catalyst Example 1, the contents of each component are: 11.1 wt% of silver in atoms, 169 ppm of alkali metal cesium additive, and 94 ppm of rhenium additive in rhenium atoms.

Example 2

First, prepare 198 mL of 10wt% sulfuric acid aqueous solution in a glass beaker, then add 2g zirconium sulfate and 0.5g chitosan to the sulfuric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, and add the above immersion liquid to completely immerse the carrier. Evacuate to above 10 mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10wt% ammonia solution in a glass, then add 1.3g of ammonium tungstate (H ₂₆ N ₆ O ₄₀ W ₁₂ ) to the ammonia solution, and mix it evenly. Place the heated carrier impregnated with the dilute sulfuric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 2.

The contents of each component supported on the surface of the carrier Example 2 are: 0.23 wt% of hollow-configured zirconium oxide and 0.025 wt% of tungsten oxide.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15 g of carrier Example 2, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare Silver Catalyst Example 2.

Relative to Silver Catalyst Example 2, the contents of each component are: 11.2 wt% of silver in atoms, 172 ppm of alkali metal cesium additive, and 96 ppm of rhenium additive in rhenium atoms.

Example 3

First, prepare 198 mL of 5wt% nitric acid aqueous solution in a glass beaker, then add 2g zirconium sulfate and 0.5g chitosan to the nitric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, and add the above immersion liquid to completely immerse the carrier. Evacuate to above 10 mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10wt% ammonia solution in a glass, then add 1.3g of ammonium tungstate (H ₂₆ N ₆ O ₄₀ W ₁₂ ) to the ammonia solution, and mix it evenly. Place the heated carrier immersed in the dilute nitric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 3.

The contents of each component supported on the surface of carrier Example 3 are: 0.21wt% of hollow-configured zirconium oxide and 0.027wt% of tungsten oxide.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15 g of the carrier Example 3, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare Silver Catalyst Example 3.

Relative to Silver Catalyst Example 3, the contents of each component are: 11.1 wt% of silver in atoms, 171 ppm of alkali metal cesium additive, and 93 ppm of rhenium additive in rhenium atoms.

Example 4

First, prepare 198 mL of 5wt% sulfuric acid aqueous solution in a glass beaker, then add 4g zirconium sulfate and 0.5g chitosan to the sulfuric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, and add the above immersion liquid to completely immerse the carrier. Evacuate to above 10 mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10wt% ammonia solution in a glass, then add 1.3g of ammonium tungstate (H ₂₆ N ₆ O ₄₀ W ₁₂ ) to the ammonia solution, and mix it evenly. Place the heated carrier impregnated with the dilute sulfuric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 4.

The contents of each component supported on the surface of the carrier Example 4 are: 0.43wt% of hollow-configured zirconium oxide and 0.026wt% of tungsten oxide.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15 g of the carrier Example 4, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare Silver Catalyst Example 4.

Relative to Silver Catalyst Example 4, the contents of each component are: 11.3 wt% of silver in atoms, 167 ppm of alkali metal cesium additive, and 92 ppm of rhenium additive in rhenium atoms.

Example 5

First, prepare 198 mL of 5wt% sulfuric acid aqueous solution in a glass beaker, then add 2g of zirconium nitrate pentahydrate and 0.5g of chitosan to the sulfuric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, add the above immersion liquid, and completely immerse the carrier. Evacuate to above 10mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10wt% ammonia solution in a glass, then add 1.3g of ammonium tungstate (H ₂₆ N ₆ O ₄₀ W ₁₂ ) to the ammonia solution, and mix it evenly. Place the heated carrier impregnated with the dilute sulfuric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 5.

The contents of each component supported on the surface of carrier Example 5 are: 0.14wt% of hollow-configured zirconium oxide and 0.025wt% of tungsten oxide.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15 g of the carrier Example 5, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare Silver Catalyst Example 5.

Relative to Silver Catalyst Example 5, the contents of each component are: 11.2 wt% of silver in atoms, 173 ppm of alkali metal cesium additive, and 95 ppm of rhenium additive in rhenium atoms.

Example 6

First, prepare 198 mL of 5wt% sulfuric acid aqueous solution in a glass beaker, then add 2g of zirconium sulfate and 1g of chitosan to the sulfuric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, and add the above immersion liquid to completely immerse the carrier. Evacuate to above 10 mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10wt% ammonia solution in a glass, then add 1.3g of ammonium tungstate (H ₂₆ N ₆ O ₄₀ W ₁₂ ) to the ammonia solution, and mix it evenly. Place the heated carrier impregnated with the dilute sulfuric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 6.

The contents of each component supported on the surface of carrier Example 6 are: 0.22wt% of hollow-configured zirconium oxide and 0.027wt% of tungsten oxide.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15 g of the carrier Example 6, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare Silver Catalyst Example 6.

Compared with Silver Catalyst Example 6, the contents of each component are: 11.0 wt% of silver in atoms, 171 ppm of alkali metal cesium additive, and 92 ppm of rhenium additive in rhenium atoms.

Example 7

First, prepare 198 mL of 5wt% sulfuric acid aqueous solution in a glass beaker, then add 2g of zirconium sulfate and 0.5g of polystyrene microspheres to the sulfuric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, and add the above immersion liquid to completely immerse the carrier. Evacuate to above 10 mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10wt% ammonia solution in a glass, then add 1.3g of ammonium tungstate (H ₂₆ N ₆ O ₄₀ W ₁₂ ) to the ammonia solution, and mix it evenly. Place the heated carrier impregnated with the dilute sulfuric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 7.

The contents of each component supported on the surface of carrier Example 7 are: 0.23% wt% of hollow-configured zirconia and 0.026% by weight of tungsten oxide.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15 g of the carrier Example 7, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare Silver Catalyst Example 7.

Compared with Silver Catalyst Example 7, the contents of each component are: 11.3 wt% of silver in atoms, 174 ppm of alkali metal cesium additive, and 96 ppm of rhenium additive in rhenium atoms.

Example 8

First, prepare 198 mL of 5wt% sulfuric acid aqueous solution in a glass beaker, then add 2g zirconium sulfate and 0.5g chitosan to the sulfuric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, and add the above immersion liquid to completely immerse the carrier. Evacuate to above 10 mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10 wt% ammonia solution in a glass, then add 2.6 g of ammonium tungstate (H ₂₆ N ₆ O ₄₀ W ₁₂ ) into the ammonia solution, and mix it evenly. Place the heated carrier impregnated with the dilute sulfuric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 8.

The contents of each component supported on the surface of the carrier Example 8 are: 0.21 wt% of hollow-configured zirconium oxide and 0.052 wt% of tungsten oxide.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15 g of the carrier Example 8, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare silver catalyst Example 8.

Relative to Silver Catalyst Example 8, the contents of each component are: 11.2 wt% of silver in atoms, 173 ppm of alkali metal cesium additive, and 91 ppm of rhenium additive in rhenium atoms.

Example 9

First, prepare 198 mL of 5wt% sulfuric acid aqueous solution in a glass beaker, then add 2g zirconium sulfate and 0.5g chitosan to the sulfuric acid aqueous solution, and mix them evenly. Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, and add the above immersion liquid to completely immerse the carrier. Evacuate to above 10 mmHg and maintain it for about 15 minutes. Then leaching to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes. Prepare 200 mL of 10 wt% ammonia solution in a glass, then add 1.3 g of tungstic acid to the ammonia solution, mix and stir evenly. Place the heated carrier impregnated with the dilute sulfuric acid solution of zirconium sulfate and chitosan into a vacuum-capable glass container, and add ammonium tungstate ammonia immersion solution to completely immerse the carrier. Evacuate to above 10mmHg, keep it for about 15 minutes, leach to remove excess solution, place the impregnated carrier sample in an air flow of 400°C and heat it for about 3 minutes, and finally heat it at 900°C for 1 hour, and it is ready Vector Example 9.

The contents of each component supported on the surface of the carrier Example 9 are: 0.23 wt% of hollow-configured zirconium oxide and 0.026 wt% of tungsten oxide.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15 g of the carrier Example 9, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow at 350° C. and heated for about 2 minutes to prepare Silver Catalyst Example 9.

Relative to Silver Catalyst Example 9, the contents of each component are: 11.0 wt% of silver in atoms, 172 ppm of alkali metal cesium additive, and 94 ppm of rhenium additive in rhenium atoms.

Comparative example 1

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15g of α-alumina carrier, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow of 350° C. and heated for about 2 minutes to prepare silver catalyst comparative example 1.

Compared with Silver Catalyst Comparative Example 1, the contents of each component are: 11.1 wt% of silver in atoms, 170 ppm of alkali metal cesium additive, and 93 ppm of rhenium additive in terms of rhenium atoms.

Comparative example 2

The difference from Example 8 is that no tungsten compound was added and 2.4g of zirconium sulfate was added. The content of each component supported on the surface of the carrier Comparative Example 2 is: 0.26 wt% of hollow-configured zirconia.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15g of the carrier Comparative Example 2, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow of 350° C. and heated for about 2 minutes to prepare silver catalyst comparative example 2.

Compared with Silver Catalyst Comparative Example 2, the contents of each component are: 11.2 wt% of silver in atoms, 168 ppm of alkali metal cesium additive, and 96 ppm of rhenium additive in rhenium atoms.

Comparative example 3

The difference from Example 8 is that no zirconium compound was added and 13.7 g of ammonium tungstate was added.

The content of each component supported on the surface of carrier comparative example 3 is: tungsten oxide 0.26wt%.

Add 32.1g ethylenediamine, 10.8g ethanolamine and 179.8g deionized water to a glass beaker with stirring to obtain a mixed solution; slowly add 72.2g silver oxalate into the mixed solution, keep the temperature below 40°C and continue stirring until The silver oxalate is completely dissolved; then add 2.25mL of cesium nitrate aqueous solution (the concentration is 0.03995g/mL, based on the weight of the cesium atom) and 2.78mL of the ammonium perrhenate aqueous solution (the concentration is 0.0162g/mL, based on the weight of the rhenium atom), Mix evenly to make 300g of dipping solution and set aside.

Take 15g of the carrier Comparative Example 3, put it into a vacuum-capable glass container, add the above silver amine impregnation solution, and completely immerse the carrier. Evacuate to above 10mmHg, hold for about 15 minutes, and then drain to remove excess solution. Finally, the impregnated carrier sample was placed in an air flow of 350° C. and heated for about 2 minutes to prepare silver catalyst comparative example 3.

Compared with Silver Catalyst Comparative Example 3, the contents of each component are: 11.3 wt% of silver in atoms, 174 ppm of alkali metal cesium additive, and 91 ppm of rhenium additive in rhenium atoms.

For the silver catalysts in the examples and comparative examples, a microreactor evaluation device was used to measure the performance of the catalyst samples under the aforementioned process conditions. The evaluation results are shown in Table 2.

Table 2 Evaluation results of silver catalyst comparative examples 1 to 3 and examples 1 to 9

It can be seen from Table 1 that the selectivity and reactivity of the silver catalyst sample prepared by using α-alumina carrier surface composite modification technology are significantly improved.

The embodiments of the present invention have been described above. The above description is illustrative, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

The endpoints of ranges and any values disclosed herein are not limited to the precise range or value, but these ranges or values are to be understood to include values approaching such ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges. These values The scope shall be deemed to be specifically disclosed herein.

Claims (13)

1. A carrier for preparing a silver catalyst, characterized in that the carrier comprises:

α-Al ₂ O ₃ Carrier, supported on alpha-Al ₂ O ₃ Zirconium oxide and tungsten oxide with hollow configuration on the surface of the carrier;

relative to the alpha-Al ₂ O ₃ The carrier comprises the following components in percentage by weight:

0.02 to 4.00 weight percent of zirconia with hollow structure and 0.002 to 0.500 weight percent of tungsten oxide.

2. The carrier for preparing a silver catalyst according to claim 1, wherein,

relative to the alpha-Al ₂ O ₃ The carrier comprises the following components in percentage by weight:

0.05 to 1.00 weight percent of zirconia with hollow structure and 0.005 to 0.100 weight percent of tungsten oxide.

3. The carrier for preparing a silver catalyst according to claim 1 or 2, wherein the α -Al ₂ O ₃ The carrier comprises at least one of the following features:

α-A1 ₂ O ₃ the content is more than or equal to 90 percent;

crushing strength is 20-200N/grain;

the specific surface area is 0.2-3.0 m ² /g；

The water absorption rate is more than or equal to 30 percent;

the pore volume is 0.30-0.85 mL/g.

4. A method for preparing a carrier for preparing a silver catalyst, the method comprising:

(1) alpha-A1 ₂ O ₃ Soaking in the first solution, then carrying out solid-liquid separation and drying;

(2) Soaking the carrier obtained in the step (1) in a second solution, and then carrying out solid-liquid separation, drying and roasting to obtain the carrier for preparing the silver catalyst;

the first solution is a mixed solution of acid, zirconium salt and a template agent;

The second solution is a tungstic acid and/or tungstate solution, and the solvent of the tungstate solution is at least one selected from water, ammonia water and amine compounds.

5. The preparation method according to claim 4, wherein,

in the step (1), the soaking time is 10-300 minutes, and the soaking is performed under the pressure of 100 mmHg;

in the step (2), the soaking time is 10-300 minutes, and the soaking is performed under the pressure of 100 mmHg;

in the step (1), drying is carried out in air or in a nitrogen-oxygen mixture with an oxygen content of not more than 21%; the drying temperature is 100-600 ℃, preferably 150-500 ℃; the drying time is 0.5 to 120 minutes, preferably 1 to 30 minutes;

in the step (2), drying is carried out in air or in a nitrogen-oxygen mixture with an oxygen content of not more than 21%; the drying temperature is 100-600 ℃, preferably 150-500 ℃; the drying time is 0.5 to 120 minutes, preferably 1 to 30 minutes;

in the step (2), roasting is carried out in air or in a nitrogen-oxygen mixture with the oxygen content not more than 21%; the roasting temperature is 500-1400 ℃, preferably 700-1200 ℃; the calcination time is 5 to 240 minutes, preferably 10 to 120 minutes.

6. The preparation method according to claim 4, wherein,

The acid is at least one selected from sulfuric acid, nitric acid and oxalic acid;

the zirconium salt is at least one selected from zirconium sulfate, zirconium nitrate and zirconyl nitrate;

the template agent is at least one of chitosan, polystyrene and glucosamine;

preferably, the content of the acid is 0.2 to 20.0wt percent, the content of the zirconium salt is 0.05 to 10.00wt percent, and the content of the template agent is 0.02 to 6.0wt percent based on the total weight of the first solution;

more preferably, the acid content is 1.0 to 15.0wt%, the zirconium salt content is 0.1 to 5.0wt%, and the templating agent content is 0.05 to 3.0wt%, based on the total weight of the first solution;

the tungstate is ammonium tungstate and/or potassium tungstate;

preferably, the content of the tungstic acid and/or tungstate is 0.002 to 0.500wt percent based on the total weight of the second solution;

more preferably, the content of tungstic acid and/or tungstate is 0.01 to 0.20wt% based on the total weight of the second solution.

7. A carrier obtainable by the process of any one of claims 4 to 6.

8. A silver catalyst, characterized in that the silver catalyst comprises:

a carrier, silver loaded on the surface of the carrier, an alkali metal auxiliary agent, an optional rhenium auxiliary agent and an optional co-auxiliary agent of the rhenium auxiliary agent;

The carrier is the carrier for preparing a silver catalyst according to claim 1 or 2 or 3, or the carrier according to claim 7.

9. The silver catalyst according to claim 8, wherein,

the content of each component relative to the silver catalyst is as follows:

silver 2-39 wt% in atom, alkali metal promoter 1-2000 ppm, rhenium promoter 0-2000 ppm in atom and rhenium promoter co-promoter 0-2000 ppm in atom;

preferably, the silver is 10-35 wt% in atomic terms, the alkali metal promoter is 5-2000 ppm, the rhenium promoter is 100-1000 ppm in atomic terms, and the co-promoter of the rhenium promoter is 100-1000 ppm in atomic terms.

10. The silver catalyst according to claim 8, wherein,

the alkali metal auxiliary agent is at least one of compounds of lithium, sodium, potassium, rubidium and cesium respectively;

the rhenium promoter is selected from at least one of rhenium oxide, perrhenic acid, cesium perrhenate, methyl rhenium trioxide (VII) and ammonium perrhenate;

the co-promoter of the rhenium promoter is selected from at least one of salts or acids containing manganese, chromium, sulfur, cobalt, molybdenum, nickel.

11. The method for producing a silver catalyst according to any one of claims 8 to 10, characterized in that the method comprises:

Soaking the carrier in silver ammonia solution, carrying out solid-liquid separation and drying to obtain the silver catalyst;

preferably, the time of the impregnation is 10 to 300 minutes, and the impregnation is performed under a pressure of 100mmHg or less;

preferably, the drying is carried out in air or in a mixture of nitrogen and oxygen having an oxygen content of not more than 21%, the drying temperature being between 100 and 600 ℃, more preferably between 150 and 500 ℃; the drying time is 0.5 to 120 minutes, more preferably 1 to 30 minutes.

12. The method for producing a silver catalyst according to claim 11, wherein,

the silver ammonia solution comprises a silver-containing compound, an amine compound, water, an alkali metal auxiliary agent, an optional rhenium auxiliary agent and an optional rhenium auxiliary agent; the content of the amine compound is 10-90 wt% based on the total weight of the silver-ammonia solution;

preferably, the silver-containing compound is selected from at least one of silver acetate, silver nitrate and silver oxalate;

preferably, the amine compound is selected from at least one of ammonia, ethylamine, N-propylamine, ethylenediamine, 1, 3-propylenediamine, 1, 4-butylenediamine, N-dimethylformamide, ethanolamine and propanolamine.

13. Use of the silver catalyst of any one of claims 8-10 in a reaction for the oxidation of ethylene to produce ethylene oxide.