CN108607617B - Method for preparing alumina carrier for silver catalyst and silver catalyst - Google Patents

Method for preparing alumina carrier for silver catalyst and silver catalyst Download PDF

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CN108607617B
CN108607617B CN201611126332.XA CN201611126332A CN108607617B CN 108607617 B CN108607617 B CN 108607617B CN 201611126332 A CN201611126332 A CN 201611126332A CN 108607617 B CN108607617 B CN 108607617B
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carrier
alumina
solid
silver catalyst
pore volume
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CN108607617A (en
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李旻旭
林伟
蒋军
李金兵
林强
廉括
曹淑媛
高立新
孙向华
隗永清
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Sinopec Beijing Research Institute of Chemical Industry
China Petroleum and Chemical Corp
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China Petroleum and Chemical Corp
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/02—Boron or aluminium; Oxides or hydroxides thereof
    • B01J21/04—Alumina
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/48—Silver or gold
    • B01J23/50—Silver
    • B01J35/612—
    • B01J35/635—
    • B01J35/69—
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D301/00—Preparation of oxiranes
    • C07D301/02—Synthesis of the oxirane ring
    • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
    • C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
    • C07D301/08—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
    • C07D301/10—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase with catalysts containing silver or gold
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
    • C07D303/02—Compounds containing oxirane rings
    • C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms

Abstract

The invention relates to a method for preparing an alumina carrier for a silver catalyst, which comprises the following steps: s1, premixing the combustible solid particle material and vaseline to obtain a pasty solid mixture containing solid particles; s2, preparing a mixed material containing alumina trihydrate, pseudo-alumina monohydrate and a fluoride mineralizer; and S3, mixing the pasty solid particle-containing solid mixture in the step S1 with the mixed material in the step S2, adding acid liquor, kneading, forming the kneaded material, drying and roasting to obtain the carrier. The invention also relates to a catalyst prepared by using the carrier.

Description

Method for preparing alumina carrier for silver catalyst and silver catalyst
Technical Field
The invention relates to a method for preparing an alumina carrier for a silver catalyst, in particular to a method for preparing an alumina carrier for a silver catalyst used for producing ethylene oxide by ethylene epoxidation.
Background
Ethylene oxide is one of the most demanding ethylene derivatives as a chemical product, and the ethylene oxide is generally produced by a direct oxidation method of ethylene in industry. The silver catalyst is a catalyst commonly used in the reaction for preparing ethylene oxide by ethylene epoxidation in industry, and usually takes alumina as a carrier, silver as an active component and a small amount of auxiliary agent to improve the catalytic performance of the silver catalyst, and a side reaction can occur in the silver catalyst reaction to generate carbon dioxide and water through deep oxidation, so that the activity, selectivity and stability of the catalyst are three main performance indexes in practical application. The activity is the space-time yield for the catalyst or the reaction temperature required at a certain space-time yield; the higher the space-time yield applicable or the lower the reaction temperature required at a certain space-time yield, the higher the activity of the silver catalyst. Selectivity refers to the ratio of the moles of ethylene converted to ethylene oxide as the main product of the reaction to the total moles of ethylene reacted. Stability is expressed as the rate of decay of the activity and/or selectivity of the catalyst under certain reaction conditions, the smaller the rate of decline, the longer the catalyst can be used and the better the stability of the catalyst. The performance of the silver catalyst in the process of producing ethylene oxide by oxidizing ethylene has great influence on economic benefit, and the improvement of the activity, selectivity and stability of the silver catalyst is the main direction of the research of the silver catalyst.
Besides being related to key components and auxiliary agents, the performance of the catalyst is also closely related to the heat and mass transfer characteristics of the catalyst carrier. The carrier can increase the specific surface area of the catalyst, improve the dispersion degree of the active component, enhance the heat resistance and the mechanical strength, protect and support the active component in the reaction process, and sometimes play a role of a cocatalyst or a cocatalyst. In order to improve the performance of the silver catalyst, it is one of the main means to improve the mass transfer and heat transfer performance of the carrier. In WO1997040933 oxides of zirconium, titanium, silicon and alkaline earth metals (calcium, magnesium, strontium) are added to the support to improve the catalyst performance. In CN104549545, silica and magnesium are introduced into alumina carrier of silver catalyst for olefin epoxidation, which improves selectivity of catalyst obviously. CN1400048 uses cerium or zirconium containing sol to dip and treat alpha-alumina carrier, then silver and promoter are loaded to prepare silver catalyst, which improves the performance of the catalyst. The above patent documents mainly adopt the way of adding auxiliary agent to silver catalyst carrier to change components to improve the performance of catalyst.
Except for changing the method of the carrier components, the proportion of macropores and the average pore diameter in the carrier are improved, the proportion of connected pores can be improved, and the number of closed pores and semi-through pores is reduced, so that the mass transfer and heat transfer performance of the catalyst in the reaction is effectively improved. In US4242235 the pore volume of the carrier prepared by the silver catalyst for preparing ethylene oxide by ethylene epoxidation is 0.1-0.6mL/g, and the pore diameter is in bimodal distribution. In CN1164563, the pore volume of the alumina carrier prepared by acid-base change gelling is 0.55-0.75mL/g, and the pore diameter
Figure BDA0001175277810000021
The concentrated wells of (a) account for 75-90% of the total pore volume. CN103055947 uses activated carbon fiber as pore-enlarging agent to prepare alumina carrier with pore distribution mainly at 10-20nm, and contains a small amount of macropores with pore diameter above 100 nm. CN101795762A provides a carrier for a catalyst for the epoxidation of an olefin which comprises an inert, refractory solid carrier which has no or little absolute volume from small pores of less than 1 micron and large pores of greater than 5 microns.
Although the above patent documents adopt different methods to improve the alumina carrier, for the process of preparing ethylene oxide by gas-phase high-temperature high-pressure ethylene epoxidation, the required carrier needs larger pore diameter and pore volume to improve the mass transfer and heat transfer performance of the catalyst, and how to increase the pore diameter and pore volume of the carrier in a reasonable range is one of the requirements.
Disclosure of Invention
Under the background of the prior art, the inventor of the present invention has conducted a great deal of experimental research in the field of silver catalysts and alumina carriers thereof, and as a result, found that by improving the addition mode of pore-forming agents, solid particles with fixed forms are pre-dispersed in oleophilic and hydrophobic vaseline with fluidity as pore-forming agents, the pore size and pore distribution of alumina carriers can be effectively adjusted, the pore volume is increased, and due to hydrophobic coating of vaseline on solid particles, a phase interface can be theoretically formed in the subsequent acid solution adding step to maintain the relationship between the pore-forming agents, reduce the probability of formation of closed pores and semi-through pores, and further improve the performance of silver catalysts.
According to an aspect of the present invention, there is provided a method for preparing an alumina carrier for silver catalyst, comprising the steps of:
s1, premixing the combustible solid particle material and vaseline to obtain a pasty solid mixture containing solid particles;
s2, preparing a mixed material containing alumina trihydrate, pseudo-alumina monohydrate and a fluoride mineralizer;
and S3, mixing the pasty solid particle-containing solid mixture in the step S1 with the mixed material in the step S2, adding acid liquor, kneading, forming the kneaded material, drying and roasting to obtain the carrier.
According to the method provided by the invention, vaseline and a combustible solid particle material are premixed to obtain an oil-soluble paste solid mixture containing solid particles as a pore forming agent, and other materials are mixed to prepare the carrier, so that the pore diameter and pore distribution of the alumina carrier can be effectively adjusted, the pore volume is improved, the probability of formation of closed pores and semi-through pores is reduced, and the performance of a subsequently obtained silver catalyst is further improved.
According to a preferred embodiment of the method according to the invention, in step S1, the content of the burnable solid particulate material is 10-50 wt%, preferably 30-50 wt%, based on the total weight of the pasty solid particulate-containing solid mixture; the content of vaseline is 50-90 wt%, preferably 50-70 wt%.
According to a preferred embodiment of the method according to the invention, in step S1, the volume average particle size of the burnable solid particulate material is between 0.1 and 2000 μm and the ash content is less than 1 wt%. The mass ratio of the burnable solid particulate material to the vaseline is 0.1:1-1:1, preferably 0.4:1-1: 1.
According to a preferred embodiment of the method of the present invention, in step S1, the burnable solid particulate material is selected from one or more of petroleum coke, carbon powder, graphene powder and starch.
According to the present invention, in some specific embodiments, step I, an oil-soluble pasty solid mixture is prepared by mixing one or more solid burnable solid particulate materials such as petroleum coke, carbon powder, graphene powder, etc. with vaseline in a certain ratio (particulate matter and vaseline), wherein the solid particulate materials are 10-50 wt% and the vaseline is 50-90 wt% based on the total weight of the mixture, and preferably the solid mixture obtained after mixing is a uniform paste. The mixed materials can be carried out in a mixer or manually operated in a container, and the mark of the mixing end is that the solid mixture is in a paste with uniform color and uniformly dispersed particles.
According to a preferred embodiment of the method of the present invention, in step S2, the alumina trihydrate content is 25 to 80 wt%, the pseudo-alumina monohydrate content is 10 to 65 wt%, and the fluoride mineralizer is used in an amount of 0.05 to 8.0 wt%, based on weight, in the mixed material.
According to a preferred embodiment of the method of the present invention, in step S2, the fluoride mineralizer is selected from one or more of ammonium fluoride, aluminum fluoride and tetrabutylammonium fluoride, such as ammonium fluoride. The addition of the fluoride mineralizer can obviously accelerate the crystal form conversion of the alumina, change the surface morphology of the carrier and reduce the formation of small holes with the aperture of less than 0.1 mu m, which are unfavorable for mass and heat transfer.
According to a preferred embodiment of the process according to the invention, the mass ratio of alumina trihydrate to pseudo-alumina monohydrate is between 0.5:1 and 4.2: 1. The alumina trihydrate is selected from alpha-alumina trihydrate, beta-alumina trihydrate or mixtures thereof. In some specific embodiments, in step S2, the mixed material includes a barium additive. The barium assistant can be one or more of barium sulfate, barium carbonate and barium oxide. The content of the barium assistant in the mixed material is less than 5 wt%, such as 0-5 wt%, such as 0.01-5 wt%.
According to a preferred embodiment of the method according to the invention, the mixing of the material in step S2 is performed in a blender for a time period of 10-100 min. The alumina trihydrate, pseudo-monohydrate alumina, mineralizer, barium assistant and the like are reagents which are conventionally used in the field, and parameters such as particle size and the like are not described again.
In the above-mentioned preparation method of the carrier of the present invention, the order of adding the materials in the respective mixing processes is not limited.
According to a preferred embodiment of the method of the present invention, in step S3, the mass ratio of the pasty solid particle-containing mixture in step S1 to the mixed material in step S2 is 1:3-1: 50. In some specific embodiments, the weight ratio of the two is 1:5 to 1: 10.
According to a preferred embodiment of the method of the present invention, in step S3, the acid solution for kneading is an aqueous solution of one or more of nitric acid, acetic acid, or citric acid. The acid solution may be present in a concentration of from 10 to 80 wt%, such as from 20 to 50 wt%. The acid solution is used in an amount conventional in the art, such as 10 to 50 wt% based on the total weight of the pasty solid-containing mixture and the mixed material. The acid solution mainly reacts with pseudo-hydrated alumina to bond materials, and because the acid solution is in an aqueous phase and is immiscible with vaseline, the premixing of the vaseline and solid particles furthest ensures that a pore-forming agent is uniformly distributed while certain connection is maintained, and communicated pore channels are formed after roasting, and meanwhile, the pore diameter of the pore channels coated by the vaseline is increased.
According to a preferred embodiment of the method of the present invention, in step S3, the kneading is carried out in a kneader for a period of 10 to 100 min; the molding is carried out in a molding machine, and the molded solid is a non-porous, single-porous or seven-porous cylindrical object; the drying is carried out in an oven, the drying temperature is 40-110 ℃, and the drying time is 1-72 h; the dried solid is roasted for 2 to 30 hours in air atmosphere at the temperature of 1200-1500 ℃, and the heating rate is 2 to 100 ℃/min. Most of the aluminum oxide has alpha crystal form after roasting.
According to the invention, the burnout solid particle material and the vaseline are added after being uniformly premixed, so that the proportion of macropores in the total pore distribution is increased, and interconnected pore channels with larger pore diameters are formed in the carrier. The mixture of the burnable solid particulate material and vaseline is completely oxidized during the firing at step S3, and the generated gas escapes.
The main component of the carrier product obtained by the preparation method is alumina, and the crystal form of the alumina is mainly alpha type. The carrier obtains the pasty pore-forming agent through the mixing operation in the step S1, so that the pore-forming effect is obviously improved in the step S3, the aperture in the carrier is increased under the condition that the crystal structure in the carrier is not damaged, the mass transfer and heat transfer of the catalyst in the reaction process are facilitated, and the possibility that ethylene is deeply oxidized to generate carbon dioxide and water as byproducts is reduced. The obtained carrier product after high-temperature roasting has a rougher surface compared with the common carrier, and part of macroscopic fine cavities are generated, but the color of the carrier product is still white, and the fine cavities with larger pore size still exist after the silver catalyst is prepared, so that the silver catalyst cannot be blocked by silver particles.
According to a preferred embodiment of the process according to the invention, the support crush strength is from 30 to 150N per pellet, preferably from 40 to 100N per pellet; the specific surface area is 0.3-3m2Per g, preferably 1.8 to 3.0m2(ii)/g; the pore volume is 50-90mL/g, preferably 70-85 mL/g; the water absorption is 60-90%, preferably 70-85%. Wherein, the crushing strength is measured by a strength meter, the specific surface data is from a test method, the pore volume and the pore peak position are from the test results of a mercury intrusion instrument, and the water absorption is measured by a boiling method. The pore size in the carrier is bimodal, the first peak is a large pore peak and the second peak is a small pore peak. Wherein the peak of the first peak is greater than 10 μm to 50 μm, such as greater than 10 μm to 30 μm; first, theThe pore volume of the pores corresponding to one peak accounts for more than 40%, such as 40-60%, of the total pore volume; the second peak is a small pore peak with a peak value of 0.1-5 μm. The pore volume of the pores corresponding to the second peak is 40-60% of the total pore volume. The pore volume of the first and second peaks constitutes substantially the entire pore volume.
According to another aspect of the present invention, there is also provided a silver catalyst for ethylene epoxidation to ethylene oxide, the silver catalyst comprising the above-described silver impregnated on a carrier. After the alumina carrier for the silver catalyst is prepared, the alumina carrier for the silver catalyst is prepared according to a solution impregnation method which is conventionally disclosed by a person skilled in the art, for example, the alumina carrier prepared by any one of the methods is immersed in a solution containing a silver compound, organic amine, alkali metal assistant and/or rhenium assistant, leaching and activating are carried out, and finally the silver catalyst is prepared.
The carrier prepared by the method has relatively large aperture and water absorption, and the prepared silver catalyst has relatively high activity, selectivity and stability, and can better meet the requirements of various ethylene oxidation production ethylene oxide synthesis conditions.
Detailed Description
The present invention is further illustrated by the following examples, but the scope of the present invention is not limited to these examples.
The method for measuring the performance of the silver catalyst comprises the following steps:
various silver catalysts prepared in the present invention were evaluated for initial catalytic reaction performance and stability using a microtubular reactor (hereinafter referred to as "microreaction"). The tubular reactor used in the microreaction evaluation device was a stainless steel reaction tube having an inner diameter of 4mm, and the reaction tube was placed in a heating jacket made of copper or aluminum. After crushing, 0.8g of catalyst particles with the size of 12-18 meshes are screened, and the catalyst particles are filled into a reactor and compacted, and an inert filler is arranged at the lower part of the reactor so that a catalyst bed layer is positioned in a constant temperature area of a heating sleeve.
The standard evaluation conditions for catalytic activity and selectivity employed in the present invention are as follows (see the examples for actual reaction conditions):
gas composition (mol%) at reaction inlet: ethylene, 29.0 ± 1.0; oxygen, 7.3 +/-0.2; the carbon dioxide is used as a source of carbon dioxide,<3.0; nitrogen, the balance; dichloroethane, 0.1-2.0 ppm. The reaction pressure is 2.1 MPa; airspeed of 6000h-1(ii) a The concentration of ethylene oxide in the reactor outlet tail gas was 2.5%.
The reactor was heated gradually from room temperature and, after the reaction had stabilized at operating conditions, the reactor inlet and outlet gas compositions were continuously measured. The measurement results were corrected for volume shrinkage, and the selectivity (S) was calculated according to the following formula:
Figure BDA0001175277810000061
where Δ EO is the difference in ethylene oxide concentration between the reactor outlet gas and the inlet gas, Δ CO2Is the difference in carbon dioxide concentration between the reactor outlet gas and the inlet gas.
Example 1
Preparation of the support
30g of petroleum coke with an average particle size of 200 μm and 30g of vaseline were thoroughly mixed in a beaker with a glass rod to give a black paste-like solid. 395g of alumina trihydrate, 95g of pseudo-alumina monohydrate and 1.4g of ammonium fluoride are uniformly mixed in a mixer to obtain white mixed powder, then the white mixed powder and the obtained black pasty solid are transferred into a kneader, 105ml of 20 wt% dilute nitric acid is added, and the mixture is fully kneaded into black pasty solid which can be extruded and molded. The resulting mixed solid was extrusion-molded into a single-hole column (pore diameter 1.5mm) having an outer diameter of 8mm and a length of 8mm in a molding machine, dried at 90 ℃ for 20 hours, and then the molded carrier was put into a kiln, elevated from room temperature to 1250 ℃ over 40 hours, and calcined at 1250 ℃ for 6 hours, to obtain a white alumina carrier.
Preparation of the catalyst
Dissolving 80g of ethylenediamine in 100g of deionized water, slowly adding 105.3g of silver oxalate into the mixed solution under stirring, keeping the temperature below 40 ℃ to completely dissolve the silver oxalate, adding 0.24g of cesium nitrate and 0.11g of amine perrhenate, and uniformly mixing to prepare an impregnation solution for later use.
Taking 30g of a carrier sample, putting the carrier sample into a container capable of being vacuumized, vacuumizing to reduce the pressure to be below 10mmHg, adding the impregnation liquid until the liquid surface is completely immersed in the solid, keeping for 30 minutes, and leaching to remove the redundant solution. The impregnated carrier is heated in air flow at 260 ℃ for 3 minutes and cooled to obtain the silver catalyst.
Example 2
The vehicle was prepared as in example 1, except that vaseline was added in an amount of 65g in the first step. The catalyst was prepared as in example 1.
Comparative example 1
The vehicle was prepared as in example 1, except that petroleum coke was directly kneaded with a mixed powder of alumina and the like without adding vaseline. The catalyst was prepared as in example 1.
Comparative example 2
Preparation of the support
395g of alumina trihydrate, 95g of pseudo-alumina monohydrate and 1.4g of ammonium fluoride are uniformly mixed in a mixer to obtain white mixed powder, then the white mixed powder is transferred into a kneader together with 30g of petroleum coke which is not mixed and 30g of vaseline, 105ml of 20 wt% dilute nitric acid is added, and the mixture is fully kneaded into black pasty solid which can be extruded and molded. The obtained mixed solid was extrusion-molded into a single-hole pillar (pore diameter 1.5mm) having an outer diameter of 8mm and a length of 8mm in a molding machine, dried at 90 ℃ for 20 hours, and then the molded carrier was put into a kiln, elevated from room temperature to 1250 ℃ over 40 hours, and calcined at 1250 ℃ for 6 hours to obtain a white alumina carrier
The catalyst was prepared as in example 1.
The carrier prepared under the above-mentioned several process conditions is tested, and the measured physical property data and pore structure distribution data of the carrier are respectively shown in the following table 1.
TABLE 1
Figure BDA0001175277810000071
It can be seen from table 1 that the pore volume, pore size and water absorption of the carrier samples of examples 1 and 2 obtained after premixing petrolatum with solid particulate petroleum coke are significantly improved compared to those of comparative example 1 and 2 without premixing with petrolatum, while the BET test specific surface is not significantly reduced; this shows that the relative amount of macropores is increased while a certain amount of micropores is retained, and the strength of example 1 and example 2 is reduced due to the increase in pore volume, but within the acceptable range for industrial use. It can be seen from the results in table 1 that the carrier prepared by the method of the present invention has significant structural features, greatly improving the pore structure. It can be seen that the support prepared by the process of this patent is structurally distinctive and that the pore structure size can be adjusted by adjusting the preparation process, e.g. example 2 increases the macropore size by increasing the amount of vaseline.
The reaction characteristics of the catalyst samples were measured using a microreactor evaluation apparatus under the aforementioned process conditions, and the test results are shown in Table 2 for each sample after one month of evaluation after the process conditions were stabilized.
TABLE 2
Figure BDA0001175277810000081
It can be seen from table 2 that the carrier products of examples 1 and 2 obtained by adding the step of premixing vaseline and solid particles have better activity and selectivity, and the selectivity rising speed is obviously faster than that of comparative examples 1 and 2, if the heat generated by the reaction is larger because the silver catalyst is used in more amount in an actual industrial device, the advantages of the carrier products of examples 1 and 2 with larger pore diameter and pore volume are more obvious than those of the carrier products of examples 2 with slightly larger pore diameter and pore volume because of the influence of mass and heat transfer effect.
Any numerical value mentioned in this specification, if there is only a two unit interval between any lowest value and any highest value, includes all values from the lowest value to the highest value incremented by one unit at a time. For example, if it is stated that the amount of a component, or a value of a process variable such as temperature, pressure, time, etc., is 50 to 90, it is meant in this specification that values of 51 to 89, 52 to 88 … …, and 69 to 71, and 70 to 71, etc., are specifically enumerated. For non-integer values, units of 0.1, 0.01, 0.001, or 0.0001 may be considered as appropriate. These are only some specifically named examples. In a similar manner, all possible combinations of numerical values between the lowest value and the highest value enumerated are to be considered to be disclosed in this application.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.

Claims (27)

1. A method for preparing an alumina carrier for preparing a silver catalyst comprises the following steps:
s1, premixing the combustible solid particle material and vaseline to obtain a pasty solid mixture containing solid particles;
s2, preparing a mixed material containing alumina trihydrate, pseudo-alumina monohydrate and a fluoride mineralizer;
and S3, mixing the pasty solid particle-containing solid mixture in the step S1 with the mixed material in the step S2, adding acid liquor, kneading, forming the kneaded material, drying and roasting to obtain the carrier.
2. The method of claim 1, wherein in step S1, the combustible solid particulate material is present in an amount of 10 to 50 wt% based on the total weight of the pasty solid particulate-containing solid mixture; the vaseline content is 50-90 wt%.
3. A method according to claim 2, wherein the content of the burnable solid particulate material is 30-50 wt%; the vaseline content is 50-70 wt%.
4. A method according to any one of claims 1 to 3, characterised in that in step S1 the volume average particle size of the burnable solid particulate material is in the range 0.1 to 2000 μm and the ash content is less than 1 wt%.
5. The method of claim 4, wherein the mass ratio of the burnable solid particulate material to petrolatum is from 0.1:1 to 1: 1.
6. The method of claim 4, wherein the mass ratio of the burnable solid particulate material to petrolatum is from 0.4:1 to 1: 1.
7. The method according to any one of claims 1 to 3, wherein in step S1, the burnable solid particulate material is selected from one or more of petroleum coke, carbon powder, graphene powder and starch.
8. The method as claimed in any one of claims 1 to 3, wherein in step S2, the alumina trihydrate content is 25 to 80 wt%, the pseudo-alumina monohydrate content is 10 to 65 wt%, and the fluoride mineralizer is used in an amount of 0.05 to 8.0 wt%, based on weight, in the mixed material.
9. A method according to any one of claims 1 to 3, wherein the alumina trihydrate is selected from alpha alumina trihydrate, beta alumina trihydrate or mixtures thereof.
10. The method according to any one of claims 1 to 3, wherein in step S2, the fluoride mineralizer is selected from one or more of ammonium fluoride, aluminum fluoride, and tetrabutylammonium fluoride.
11. The method according to any one of claims 1 to 3, wherein the mass ratio of alumina trihydrate to pseudo-alumina monohydrate is from 0.5:1 to 5: 1.
12. The method according to any one of claims 1 to 3, wherein in step S2, the mixed material includes a barium assistant.
13. The method of claim 12, wherein the barium adjuvant is one or more of barium sulfate, barium carbonate and barium oxide.
14. The method of claim 12, wherein the barium adjuvant is present in the mixed material in an amount of less than 5 wt%.
15. The method according to any one of claims 1 to 3, wherein in step S3, the mass ratio of the pasty solid particle-containing mixture in step S1 to the mixed material in step S2 is 1:3 to 1: 50.
16. The method of claim 15, wherein the mass ratio of the pasty solid-containing mixture in step S1 to the mixed material in step S2 is 1:5-1: 10.
17. The method according to any one of claims 1 to 3, wherein in step S3, the acid solution for kneading is an aqueous solution of one or more of nitric acid, acetic acid or citric acid.
18. The method as claimed in claim 17, wherein the acid solution has a concentration of 10-80 wt%.
19. The method as claimed in claim 17, wherein the acid solution has a concentration of 20-50 wt%.
20. A method according to any one of claims 1 to 3, wherein the carrier crush strength is from 30 to 150N/pellet; specific surface area of0.3-3m2(ii)/g; the pore volume is 50-90 mL/g; the water absorption rate is 60-90%.
21. The method of claim 20, wherein the carrier crush strength is from 40 to 100N/pellet; the specific surface area is 1.8-3.0m2(ii)/g; the pore volume is 70-85 mL/g; the water absorption rate is 70-85%.
22. A method according to any one of claims 1-3, characterized in that the pore size in the support is bimodal.
23. The method of claim 22, wherein the first peak has a peak value of greater than 10 μm to 50 μm.
24. The method of claim 22, wherein the first peak has a peak value of greater than 10 μm to 30 μm.
25. The method of claim 22, wherein the first peak has a pore volume corresponding to pores that comprise greater than 40% of the total pore volume.
26. The method of claim 22, wherein the first peak has a pore volume of pores that is between 40% and 60% of the total pore volume.
27. A silver catalyst for ethylene epoxidation to ethylene oxide, said silver catalyst comprising the alumina support prepared by the preparation method of any one of claims 1 to 26 impregnated with silver.
CN201611126332.XA 2016-12-09 2016-12-09 Method for preparing alumina carrier for silver catalyst and silver catalyst Active CN108607617B (en)

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CN101850243A (en) * 2009-04-02 2010-10-06 中国石油化工股份有限公司 Carrier of silver catalyst for producing ethylene oxide, preparation method thereof, silver catalyst prepared by using same and application thereof in producing ethylene oxide
CN102397795A (en) * 2010-09-13 2012-04-04 中国石油化工股份有限公司 Silver catalyst carrier for ethylene oxide production, preparation method, silver catalyst prepared by silver catalyst carrier, and application thereof

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US5929259A (en) * 1996-06-05 1999-07-27 Shell Oil Company Preparation of ethylene oxide and catalyst
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CN102397795A (en) * 2010-09-13 2012-04-04 中国石油化工股份有限公司 Silver catalyst carrier for ethylene oxide production, preparation method, silver catalyst prepared by silver catalyst carrier, and application thereof

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