Alumina carrier and preparation method thereof

Abstract

The invention relates to the technical field of catalyst carrier preparation, and discloses an alumina carrier and a preparation method thereof, the preparation method of the alumina carrier comprises the following steps: 1) contacting a first slurry containing alginate and an aluminum-containing compound with a solution or colloid containing modified cellulose to obtain a second slurry; 2) dropwise adding the second slurry obtained in the step 1) into a solution containing multivalent metal cations, and carrying out a cross-linking reaction to obtain cured particles; and (3) calcining the cured particles obtained in the step (2). According to the method, it can be guaranteed that the aluminum oxide particles are not affected by temperature, humidity and other factors in the preparation process, the morphology is kept stable, cracking and cracking do not occur, and meanwhile the good strength performance is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst carrier preparation, and in particular to an alumina carrier and a preparation method thereof. Background Art

[0002] Catalyst carriers are important consumables in chemical and industrial catalysis. Alumina is widely used as an industrial catalyst carrier due to its excellent physical and chemical properties and good stability.

[0003] The drop ball method is a common technology for forming alumina particles. Alginate and aluminum-containing compounds are mixed and stirred into a slurry, which is then dropped into a calcium chloride solution to form drop balls. Alumina particles are then prepared through drying and calcination. However, the alumina particles prepared by this method will crack and break during the forming and calcination process due to changes in temperature and humidity, resulting in a decrease in the strength and stability of the particles. The breakage of particles during use will increase the fluid pressure drop, thereby increasing the difficulty and cost of industrial production. Therefore, it is crucial to solve the problem of cracking of particles during the preparation process. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem of cracking of particles in the preparation process in the prior art, and to provide an alumina carrier and a preparation method thereof. Through the method of the present invention, it can be ensured that the alumina particles are not affected by temperature, humidity and other factors during the preparation process, maintain a stable morphology, do not crack or rupture, and at the same time obtain good strength performance.

[0005] In order to achieve the above object, the present invention provides a method for preparing an alumina carrier, wherein the method comprises the following steps:

[0006] 1) contacting a first slurry containing alginate and an aluminum-containing compound with a solution or colloid containing modified cellulose to obtain a second slurry;

[0007] 2) dropping the second slurry obtained in step 1) into a solution containing multivalent metal cations to carry out a cross-linking reaction to obtain solidified particles;

[0008] 3) The step of calcining the solidified particles obtained in step 2).

[0009] Preferably, the content of the modified cellulose in the solution or colloid containing the modified cellulose is 0.01% by mass or more, preferably 5-15% by mass, and more preferably 7-10% by mass.

[0010] Preferably, the solvent in the solution or colloid containing modified cellulose is water.

[0011] Preferably, the modified cellulose is hydroxypropyl methylcellulose and / or hydroxyethyl cellulose.

[0012] Preferably, the content of alginate in the first slurry is 0.1-3% by mass, preferably 0.2-2% by mass, more preferably 0.3-1% by mass, and more preferably 0.5-0.8% by mass.

[0013] Preferably, the content of the aluminum-containing compound in the first slurry is 15-55% by mass, preferably 20-40% by mass, and more preferably 25-30% by mass.

[0014] Preferably, the mass ratio of the aluminum-containing compound in the first slurry to the alginate in the first slurry is 10-80:1, preferably 15-60:1, more preferably 20-40:1, more preferably 35-40:1.

[0015] Preferably, the alginate is one or more of sodium alginate, potassium alginate, magnesium alginate and ammonium alginate.

[0016] Preferably, the aluminum-containing compound is one or more of pseudo-boehmite, alumina, diaspore and boehmite.

[0017] Preferably, the mass ratio of the first slurry to the solution or colloid containing modified cellulose is 5-60:1, preferably 8-40:1, and more preferably 10-30:1.

[0018] Preferably, the polyvalent metal cations in the solution containing polyvalent metal cations are selected from one or more of aluminum ions, zinc ions, calcium ions, copper ions, iron ions, ferrous ions, cobalt ions, manganese ions and nickel ions.

[0019] Preferably, the concentration of the polyvalent metal cations in the solution containing polyvalent metal cations is greater than 0.01 mol / L, preferably 0.5-10 mol / L, more preferably 0.8-5 mol / L, more preferably 0.8-2 mol / L.

[0020] Preferably, the method further comprises: a step of performing solid-liquid separation after the cross-linking reaction to obtain the solid particles.

[0021] Preferably, the calcination is carried out in three stages, the temperature of the first stage is 80-120°C, the holding time is 10-40min, the temperature of the second stage is 330-370°C, the holding time is 10-40min, and the temperature of the third stage is 520-570°C, the holding time is 30-250min.

[0022] According to a second aspect of the present invention, there is provided an alumina carrier prepared by the method for preparing the alumina carrier according to the first aspect of the present invention.

[0023] Through the above technical scheme, the present invention adds modified cellulose and combines other steps of the present invention to ensure that the alumina particles are not affected by temperature, humidity and other factors during the preparation process, maintain a stable morphology, do not crack or rupture, and obtain good strength performance.

[0024] Furthermore, compared with other preparation methods, the method of the present invention does not use acid in the preparation process, thus reducing environmental protection cost expenditure, and has low cost, simple operation and simple equipment. DETAILED DESCRIPTION

[0025] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0026] One aspect of the present invention provides a method for preparing an alumina carrier, wherein the method comprises the following steps:

[0027] 1) contacting a first slurry containing alginate and an aluminum-containing compound with a solution or colloid containing modified cellulose to obtain a second slurry;

[0028] 2) dropping the second slurry obtained in step 1) into a solution containing multivalent metal cations to carry out a cross-linking reaction to obtain solidified particles;

[0029] 3) The step of calcining the solidified particles obtained in step 2).

[0030] According to the present invention, preferably, the content of the modified cellulose in the solution or colloid containing modified cellulose is 0.01 mass % or more; more preferably, the content of the modified cellulose in the solution or colloid containing modified cellulose is 5-15 mass %; more preferably, the content of the modified cellulose in the solution or colloid containing modified cellulose is 7-10 mass %.

[0031] When the content of the modified cellulose in the solution or colloid containing the modified cellulose is within the above range, the preparation is simple, the viscosity is suitable, and the handling is convenient.

[0032] According to the present invention, preferably, the solvent in the solution or colloid containing modified cellulose is water.

[0033] In the present invention, the solution or colloid containing modified cellulose can be obtained by mixing the modified cellulose with the solvent. The mixing is not particularly limited as long as the solution or colloid containing modified cellulose in which the modified cellulose is uniformly dispersed can be obtained.

[0034] According to the present invention, preferably, the modified cellulose is hydroxypropyl methylcellulose and / or hydroxyethyl cellulose.

[0035] According to the present invention, preferably, the content of alginate in the first slurry is 0.1-3 mass %; more preferably, the content of alginate in the first slurry is 0.2-2 mass %; further preferably, the content of alginate in the first slurry is 0.3-1 mass %; further preferably, the content of alginate in the first slurry is 0.5-0.8 mass %.

[0036] According to the present invention, preferably, the content of aluminum-containing compounds in the first slurry is 15-55 mass %; more preferably, the content of aluminum-containing compounds in the first slurry is 20-40 mass %; further preferably, the content of aluminum-containing compounds in the first slurry is 25-30 mass %.

[0037] According to the present invention, preferably, the mass ratio of the aluminum-containing compound in the first slurry to the alginate in the first slurry is 10-80:1; more preferably, the mass ratio of the aluminum-containing compound in the first slurry to the alginate in the first slurry is 15-60:1; further preferably, the mass ratio of the aluminum-containing compound in the first slurry to the alginate in the first slurry is 20-40:1; preferably, the mass ratio of the aluminum-containing compound in the first slurry to the alginate in the first slurry is 35-40:1.

[0038] According to the present invention, preferably, the solvent used in the first slurry is water.

[0039] According to the present invention, preferably, the alginate is one or more of sodium alginate, potassium alginate, magnesium alginate and ammonium alginate; more preferably, the alginate is sodium alginate and / or potassium alginate; further preferably, the alginate is sodium alginate.

[0040] According to the present invention, the aluminum-containing compound can be various aluminum-containing compounds used in the art to prepare alumina carriers. For example, the aluminum-containing compound is one or more of pseudo-boehmite, alumina, hard water water stone and soft water water stone; preferably, the aluminum-containing compound is pseudo-boehmite.

[0041] According to the present invention, preferably, the mass ratio of the first slurry to the solution or colloid containing modified cellulose is 5-60:1; more preferably, the mass ratio of the first slurry to the solution or colloid containing modified cellulose is 8-40:1; further preferably, the mass ratio of the first slurry to the solution or colloid containing modified cellulose is 10-30:1.

[0042] According to the present invention, the solution containing polyvalent metal cations is used to cause the second slurry added thereto to undergo a cross-linking reaction, thereby obtaining solid particles. The solution containing polyvalent metal cations can achieve the above-mentioned effect. Preferably, the polyvalent metal cations in the solution containing polyvalent metal cations are selected from one or more of aluminum ions, zinc ions, calcium ions, copper ions, iron ions, ferrous ions, cobalt ions, manganese ions and nickel ions; more preferably, the polyvalent metal cations in the solution containing polyvalent metal cations are selected from calcium ions.

[0043] The solvent used in the solution containing the polyvalent metal cations may be water.

[0044] Preferably, the concentration of the polyvalent metal cations in the solution containing polyvalent metal cations is greater than 0.01 mol / L; more preferably, the concentration of the polyvalent metal cations in the solution containing polyvalent metal cations is 0.5-10 mol / L; further preferably, the concentration of the polyvalent metal cations in the solution containing polyvalent metal cations is 0.8-5 mol / L; further preferably, the concentration of the polyvalent metal cations in the solution containing polyvalent metal cations is 0.8-2 mol / L; further preferably, the concentration of the polyvalent metal cations in the solution containing polyvalent metal cations is 0.5-1 mol / L.

[0045] The polyvalent metal cation source of the solution containing polyvalent metal cations may be a salt containing polyvalent metal cations.

[0046] The source of the solution containing polyvalent metal cations may be obtained by mixing a salt containing polyvalent metal cations with the above-mentioned solvent.

[0047] According to the present invention, preferably, the conditions for the cross-linking reaction include: temperature of 5-50°C, time of 1-48 hours; more preferably, the conditions for the cross-linking reaction include: temperature of 10-40°C, time of 3-24 hours; further preferably, the conditions for the cross-linking reaction include: temperature of 10-40°C, time of 18-20 hours.

[0048] In a preferred embodiment of the present invention, the conditions of the cross-linking reaction include: a temperature of 10-40° C. and a time of 18-20 hours, thereby significantly improving the strength of the obtained carrier.

[0049] The amount of the solution containing polyvalent metal cations used can be any amount as long as it can ensure that the slurry dropped into the solution containing polyvalent metal cations can be cross-linked to form solid particles, and the amount commonly used in the art can be used.

[0050] According to the present invention, preferably, the method further comprises: a step of performing solid-liquid separation after the cross-linking reaction to obtain the solid particles.

[0051] The solid-liquid separation is not particularly limited and may be a method commonly used in the art for separating solids from liquids, such as filtration, centrifugation, and the like.

[0052] According to the present invention, preferably, the method further comprises: before the calcination, a step of drying the solid particles.

[0053] The drying may be, for example, air-drying, or drying at 10-80° C. for 0.5-72 hours.

[0054] According to the present invention, preferably, the calcination is carried out in three stages, the temperature of the first stage is 80-120°C, the holding time is 10-40min, the temperature of the second stage is 330-370°C, the holding time is 10-40min, the temperature of the third stage is 520-570°C, the holding time is 30-250min; more preferably, the temperature of the first stage is 100-110°C, the holding time is 20-30min, the temperature of the second stage is 340-360°C, the holding time is 20-30min, the temperature of the third stage is 540-560°C, and the holding time is 120-180min.

[0055] Preferably, the time for the temperature of the first stage to rise to the temperature of the second stage is 10-40 minutes, preferably 20-30 minutes; the time for the temperature of the second stage to rise to the temperature of the third stage is 20-90 minutes, preferably 40-60 minutes.

[0056] According to a second aspect of the present invention, there is provided an alumina carrier prepared by the method for preparing the alumina carrier according to the first aspect of the present invention.

[0057] Example

[0058] The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.

[0059] Example 1

[0060] 7.5g of modified cellulose (hydroxypropyl methylcellulose, purchased from Taian Ruitai New Materials Co., Ltd.) was dissolved in 100ml of hot water to make a homogeneous colloid; 7.5g of pseudo-boehmite was mixed with 20ml of water, and 0.2g of sodium alginate was added to mix into a slurry. 2.0g of modified cellulose homogeneous colloid was added to the slurry, and stirred for 3.5h to mix evenly. It was dropped into a 1mol / L calcium chloride solution to form solidified particles, which were removed after reacting for 3h and dried naturally. The dried particles were placed in a muffle furnace, and the temperature was increased from room temperature to 110℃ in 30 minutes, and maintained for 30 minutes, from 110℃ to 350℃ in 60 minutes, and maintained for 30 minutes, and from 350℃ to 550℃ in 120 minutes, and maintained for 3 hours. The strength analysis of the product was carried out in accordance with the ASTM D4179-22 standard, and the appearance was observed to show that the molding was complete and good, without cracking, the particle size was 2.1±0.1mm, and the average strength was 8.5N / particle.

[0061] Example 2

[0062] 7.5g of modified cellulose (hydroxypropyl methylcellulose, purchased from Taian Ruitai New Materials Co., Ltd.) was dissolved in 100ml of hot water to make a homogeneous colloid; 7.5g of pseudo-boehmite was mixed with 20ml of water, and 0.2g of sodium alginate was added to mix into a slurry. 2.0g of modified cellulose homogeneous colloid was added to the slurry, and stirred for 19h to mix evenly. It was dropped into a 1mol / L calcium chloride solution to form solidified particles, which were removed after reacting for 1h and dried naturally. The dried particles were placed in a muffle furnace, and the temperature was increased from room temperature to 110℃ in 30 minutes, and maintained for 30 minutes, from 110℃ to 350℃ in 60 minutes, and maintained for 30 minutes, and from 350℃ to 550℃ in 120 minutes, and maintained for 3 hours. The strength analysis of the product was carried out in accordance with the ASTM D4179-22 standard, and the appearance was observed to show that the molding was complete and good, without cracking, the particle size was 1.7±0.1mm, and the average strength was 48.0N / particle.

[0063] Example 3

[0064] 7.5g of modified cellulose (hydroxypropyl methylcellulose, purchased from Taian Ruitai New Materials Co., Ltd.) was dissolved in 100ml of hot water to make a homogeneous colloid; 7.5g of pseudo-boehmite was mixed with 20ml of water, and 0.2g of sodium alginate was added to mix into a slurry. 1.0g of modified cellulose homogeneous colloid was added to the slurry, and stirred for 19h to mix evenly. It was dropped into a 1mol / L calcium chloride solution to form solidified particles, which were removed after reacting for 3h and dried naturally. The dried particles were placed in a muffle furnace, and heated from room temperature to 110℃ for 30 minutes, and kept for 30 minutes, from 110℃ to 350℃ for 60 minutes, and kept for 30 minutes, and from 350℃ to 550℃ for 120 minutes, and kept for 3 hours. The strength analysis of the product was carried out in accordance with the ASTM D4179-22 standard, and the appearance was observed to show that the molding was complete and good, without cracking, the particle size was 1.7±0.1mm, and the average strength was 53.7N / particle.

[0065] Example 4

[0066] 10.0g modified cellulose (hydroxypropyl methylcellulose, purchased from Taian Ruitai New Materials Co., Ltd.) was dissolved in 100ml hot water to make a homogeneous colloid; 7.5g pseudo-boehmite was mixed with 20ml water, and 0.2g sodium alginate was added to mix into a slurry. 2.0g modified cellulose homogeneous colloid was added to the slurry, and stirred for 3.8h to mix evenly. Drop into 1mol / L calcium chloride solution to form solidified particles, remove after 1h of reaction, and dry naturally. The dried particles were placed in a muffle furnace, from room temperature to 110℃ in 30 minutes, kept for 30 minutes, from 110℃ to 350℃ in 60 minutes, kept for 30 minutes, and from 350℃ to 550℃ in 120 minutes, kept for 3 hours. The product was analyzed for strength with reference to ASTM D4179-22 standard, and the appearance was observed to show that the molding was complete and good, without cracking, the particle size was 1.8±0.1mm, and the average strength was 33.6N / particle.

[0067] Example 5

[0068] 10.0g modified cellulose (hydroxypropyl methylcellulose, purchased from Taian Ruitai New Materials Co., Ltd.) was dissolved in 100ml hot water to make a homogeneous colloid; 7.5g pseudo-boehmite was mixed with 20ml water, and 0.2g sodium alginate was added to mix into a slurry. 2.0g modified cellulose homogeneous colloid was added to the slurry, and stirred for 3.8h to mix evenly. It was dropped into a 1mol / L calcium chloride solution to form solidified particles, which were removed after reacting for 3h and dried naturally. The dried particles were placed in a muffle furnace, and the temperature was increased from room temperature to 110℃ in 30 minutes, and maintained for 30 minutes, from 110℃ to 350℃ in 60 minutes, and maintained for 30 minutes, and from 350℃ to 550℃ in 120 minutes, and maintained for 3 hours. The strength analysis of the product was carried out in accordance with the ASTM D4179-22 standard, and the appearance was observed to show that the molding was complete and good, without cracking, the particle size was 1.7±0.1mm, and the average strength was 40.2N / particle.

[0069] Comparative Example 1

[0070] Mix 7.5g pseudo-boehmite with 20ml water, add 0.2g sodium alginate, mix into slurry, stir for 3.5h to mix evenly. Drop into 1mol / L calcium chloride solution to form solidified particles, remove after 3h of reaction, and dry naturally. Put the dried particles into a muffle furnace, from room temperature to 110℃ in 30 minutes, keep for 30 minutes, from 110℃ to 350℃ in 60 minutes, keep for 30 minutes, from 350℃ to 550℃ in 120 minutes, keep for 3 hours. Analysis of the product shows: cracking, average strength is too small, not measured.

[0071] It can be seen from Examples 1-5 and Comparative Example 1 that by adding modified cellulose, the final products of Examples 1-5 are well formed, not cracked, and have strengths between 33.6-53.7 N. In contrast, the final product of Comparative Example 1 without adding modified cellulose is cracked and has low strength.

[0072] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing an alumina carrier, characterized in that: The method comprises the following steps: 1) contacting a first slurry containing alginate and an aluminum-containing compound with a solution or colloid containing modified cellulose to obtain a second slurry; 2) dropping the second slurry obtained in step 1) into a solution containing multivalent metal cations to carry out a cross-linking reaction to obtain solidified particles; 3) The step of calcining the solidified particles obtained in step 2).

2. The method according to claim 1, wherein: The content of the modified cellulose in the solution or colloid containing the modified cellulose is 0.01% by mass or more, preferably 5-15% by mass, and more preferably 7-10% by mass; Preferably, the solvent in the solution or colloid containing modified cellulose is water.

3. The method according to claim 1, wherein: The modified cellulose is hydroxypropyl methylcellulose and / or hydroxyethyl cellulose.

4. The method according to claim 1, wherein: The content of alginate in the first slurry is 0.1-3% by mass, preferably 0.2-2% by mass, more preferably 0.3-1% by mass, and more preferably 0.5-0.8% by mass; Preferably, the content of the aluminum-containing compound in the first slurry is 15-55% by mass, preferably 20-40% by mass, and more preferably 25-30% by mass; Preferably, the mass ratio of the aluminum-containing compound in the first slurry to the alginate in the first slurry is 10-80:1, preferably 15-60:1, more preferably 20-40:1, more preferably 35-40:

1.

5. The method according to any one of claims 1 to 4, wherein: The alginate is one or more of sodium alginate, potassium alginate, magnesium alginate and ammonium alginate.

6. The method according to any one of claims 1 to 4, wherein: The aluminum-containing compound is one or more of pseudo-boehmite, alumina, diaspore and boehmite.

7. The method according to any one of claims 1 to 4, wherein: The mass ratio of the first slurry to the solution or colloid containing modified cellulose is 5-60:1, preferably 8-40:1, and more preferably 10-30:

1.

8. The method according to any one of claims 1 to 4, wherein: The polyvalent metal cations in the solution containing polyvalent metal cations are selected from one or more of aluminum ions, zinc ions, calcium ions, copper ions, iron ions, ferrous ions, cobalt ions, manganese ions and nickel ions; Preferably, the concentration of the polyvalent metal cations in the solution containing polyvalent metal cations is greater than 0.01 mol / L, preferably 0.5-10 mol / L, more preferably 0.8-5 mol / L, more preferably 0.8-2 mol / L.

9. The method according to any one of claims 1 to 4, wherein: The method further comprises: performing solid-liquid separation after the cross-linking reaction to obtain the solid particles.

10. The method according to any one of claims 1 to 4, wherein: The calcination is carried out in three stages. The temperature of the first stage is 80-120°C and the holding time is 10-40 minutes. The temperature of the second stage is 330-370°C and the holding time is 10-40 minutes. The temperature of the third stage is 520-570°C and the holding time is 30-250 minutes.

11. An alumina carrier prepared by the method for preparing an alumina carrier according to any one of claims 1 to 10.