Preparation method and application of spherical aluminum oxide efficient regenerant

Abstract

The invention relates to the technical field of aluminum oxide regenerant, in particular to a preparation method and application of a spherical aluminum oxide efficient regenerant. A preparation method of a spherical aluminum oxide efficient regenerant comprises the following steps: step 1) reacting hydrochloric acid with aluminum to prepare aluminum sol; 2) mixing an amine substance with carboxylic acid to obtain a clear solution; adding the clarified solution into the aluminum sol to obtain gel; the carboxylic acid is one or more of stearic acid, oleic acid and lactic acid; and 3) forming the gel into balls by an oil ammonia column forming method, and then aging, washing, drying and roasting to obtain the spherical aluminum oxide efficient regenerant. The spherical alumina prepared by the preparation method provided by the invention has good sphericity, relatively high specific surface area, pore volume, compressive strength and wear resistance, and is perfectly suitable for a regeneration catalyst of anthraquinone degradation products.

Description

Technical Field

[0001] This application relates to the technical field of alumina regenerators, and more specifically, to a method for preparing and applying a spherical alumina high-efficiency regenerator. Background Technology

[0002] Alumina has always been an excellent catalytic support or catalyst material. With its high stability, high specific surface area, high strength, suitable pore structure, suitable acidic sites, and rich defect sites, it has been widely used in scientific research fields such as anthraquinone degradation product regeneration and chemical production.

[0003] Currently, the main methods for forming spherical alumina include oil-ammonia column forming, oil column forming, spray drying, extrusion forming, and rotational forming. Oil-ammonia column forming is a commonly used method for forming spherical alumina. It mainly utilizes aluminum sol to solidify and form in a column composed of an oil phase and an ammonia phase. After aging, washing, drying, and calcination, spherical alumina with excellent properties such as uniform particle size, high sphericity, and high porosity is obtained.

[0004] CN1204964C uses low-viscosity organic matter as the oil phase material, and the oil phase height is lower than that of the traditional oil-ammonia column forming method. Therefore, no surfactant is used in the oil phase, avoiding ionic contamination introduced by surfactants, and high-purity alumina is prepared. However, the prepared spherical alumina has problems such as non-concentrated pore size distribution, uneven strength distribution, and low pore volume.

[0005] CN118255377A employs the organoaluminate method, mixing prepared boehmite with aluminum sol prepared from aluminum powder, followed by oil-ammonia column molding, washing, drying, and calcination to obtain alumina microspheres. The boehmite prepared by the organoaluminate method has the advantages of high purity and large pore volume; its macropores exhibit strong stability, and using it as an aluminum source can significantly improve the pore volume of alumina microspheres. However, aluminum alkoxides are not only expensive but also highly reactive. Therefore, reactions involving these precursors require the use of organic solvents to control the hydrolysis rate, which presents challenges in industrial-scale operation due to high costs and difficulties. Summary of the Invention

[0006] To address the shortcomings of conventional oil-ammonia column molding in preparing spherical alumina, such as uneven pore size distribution, inconsistent strength distribution, low pore volume, high cost, and difficult operation, this application provides a method for preparing a highly efficient spherical alumina regenerator and its application. The spherical alumina prepared by the method of this application has good sphericity, high specific surface area, pore volume, compressive strength, and wear resistance, making it perfectly suitable as a regeneration catalyst for anthraquinone degradation products.

[0007] In a first aspect, this application provides a method for preparing a highly efficient spherical alumina regenerator, employing the following technical solution: A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Hydrochloric acid reacts with aluminum to prepare aluminum sol; Step 2) Mix the amine with the carboxylic acid to obtain a clear solution; add the clear solution to the aluminum sol to obtain a gel; the carboxylic acid is one or more of stearic acid, oleic acid and lactic acid; Step 3) The gel is shaped into spheres using the oil-ammonia column molding method, followed by aging, washing, drying, and calcination to obtain a spherical alumina high-efficiency regenerator.

[0008] This application uses high-purity aluminum powder and dilute hydrochloric acid to form aluminum gel. The raw materials are widely available and low in cost, with few reaction byproducts, which can reduce the introduction of impurities and result in aluminum sol with good purity. A clear solution obtained by mixing triethanolamine aqueous solution and carboxylic acid is added to the forming sol. By adjusting the chain length of carboxylic acid, the specific surface area and pore volume of the synthesized spherical alumina can be controlled. Triethanolamine will form a stable complex with aluminum ions. Excess triethanolamine will produce an alkaline pH value, which helps the controlled hydrolysis of the complex in the early stage, thereby promoting better sphericity, lower wear rate, better strength, better specific surface area and better pore volume of spherical alumina.

[0009] The spherical alumina prepared by the method of this application has a particle size of 1-3 mm, a strength greater than 50 N (50-70 N), and a specific surface area greater than 200 m². 2 / g (200-300m 2 / g), pore volume greater than 0.40cm 3 / g, with an abrasion rate of less than 0.5%.

[0010] Preferably, the amount of carboxylic acid added is 0-10% of the mass of the aluminum sol.

[0011] Preferably, the carboxylic acid is stearic acid or lactic acid.

[0012] When lactic acid is specifically chosen as the carboxylic acid, the prepared spherical alumina has the smallest average particle size, the highest strength, and the lowest wear rate; when stearic acid is specifically chosen as the carboxylic acid, the prepared spherical alumina has the highest specific surface area, the highest pore volume, and the highest sphericity. Therefore, stearic acid or lactic acid can be specifically selected according to actual needs when choosing a carboxylic acid.

[0013] Preferably, the amine is an aqueous solution of triethanolamine.

[0014] Preferably, the amount of the amine substance added is 10-60% of the mass of the aluminum sol.

[0015] Preferably, the amount of the amine substance added is 50% of the mass of the aluminum sol.

[0016] With the increase of triethanolamine addition, spherical alumina will have better average particle size, strength, specific surface area, pore volume, sphericity and wear resistance.

[0017] Preferably, step 1) involves adding dilute hydrochloric acid to aluminum powder, stirring, and maintaining the system temperature at 50-70°C to obtain a transparent aluminum sol.

[0018] Preferably, the aluminum powder has a particle size of <150μm and a purity of >99.9wt%.

[0019] Preferably, in step 3), the oil phase used in the oil-ammonia column forming method for forming spheres is one of vacuum pump oil, kerosene, or diesel oil.

[0020] Preferably, in step 3), the oil phase height is 20-100cm.

[0021] Preferably, in step 3), the ammonia phase used in the oil-ammonia column forming method for forming spheres is ammonia water.

[0022] Preferably, in step 3), the ammonia concentration of the ammonia phase is 5-20 wt%, and the height is 20-100 cm.

[0023] Preferably, in step 3), the aging temperature is 10-30℃ and the aging time is 2-24h.

[0024] Preferably, in step 3), the drying temperature is 90-150℃ and the drying time is 2-12h.

[0025] Preferably, in step 3), the roasting temperature is 400-600℃ and the roasting time is 2-12h.

[0026] During the formation of oil-ammonia columns, as the aging and drying time increases, the specific surface area and pore volume of spherical alumina will gradually decrease, while the sphericity will gradually increase.

[0027] Secondly, this application provides an application of a highly efficient spherical alumina regenerator, which is suitable for the regeneration catalyst of anthraquinone degradation products.

[0028] In summary, this application has the following beneficial effects: This application uses the oil-ammonia column molding method to prepare spherical alumina. A clear solution formed by mixing amines and carboxylic acids is added to the molded alumina sol to form a gel. The gel is then dropped into an oil-ammonia column to solidify and form a spherical alumina high-efficiency regenerator after aging, washing, drying and calcination.

[0029] 2. Using high-purity aluminum powder and dilute hydrochloric acid to form aluminum gel, the raw materials are widely available and low in cost, with few reaction byproducts, which can reduce the introduction of impurities and the resulting aluminum sol has good purity. Adding a clear solution obtained by mixing triethanolamine aqueous solution and carboxylic acid to the forming sol, the specific surface area and pore volume of the synthesized spherical alumina can be controlled by adjusting the chain length of the carboxylic acid. Triethanolamine will form a stable complex with aluminum ions. Excess triethanolamine will produce an alkaline pH value, which helps the controlled hydrolysis of the complex in the early stage, thereby promoting better sphericity, lower wear rate, better strength, better specific surface area and better pore volume of spherical alumina.

[0030] 3. The spherical alumina prepared by the method of this application has a particle size of 1-3 mm, a strength greater than 50 N (50-70 N), and a specific surface area greater than 200 m². 2 / g (200-300m 2 / g), pore volume greater than 0.40cm 3 / g, with an abrasion rate of less than 0.5%. Detailed Implementation

[0031] The present application will be further described in detail below with reference to Examples 1-7 and Comparative Example 1.

[0032] raw material Aluminum powder was purchased from Aladdin Reagent (Shanghai) Co., Ltd., with a purity of 99.95 wt% and a particle size of 25 μm; triethanolamine, stearic acid, oleic acid, and lactic acid were also purchased from Aladdin Reagent (Shanghai) Co., Ltd.

[0033] Example 1 A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Add 18g of aluminum powder with a particle size of 25μm to 130g of dilute hydrochloric acid aqueous solution with a concentration of 10wt%, and stir continuously at 70℃ for 8h to prepare a clear and transparent aluminum sol. Step 2) Add 150g of triethanolamine to 250ml of deionized water and stir until dissolved to obtain an aqueous solution of triethanolamine. Then mix the aqueous solution of triethanolamine with 10g of stearic acid and stir continuously to obtain a clear solution. Finally, add the clear solution to the aluminum sol and stir thoroughly at a constant temperature of 80℃ to obtain a gel. Step 3) Drop the gel into an oil-ammonia column with a kerosene height of 25 cm, an ammonia water height of 50 cm, and an ammonia water concentration of 8 wt%, and let it form spheres. After aging for 2 hours, take out the formed gel spheres, wash them with deionized water, dry them in an oven at 90°C for 8 hours, and calcine them at 550°C for 2 hours to obtain a spherical alumina high-efficiency regenerator.

[0034] Among them, the spherical alumina high-efficiency regenerator is suitable for the regeneration catalyst of anthraquinone degradation products.

[0035] Example 2 A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Add 18g of aluminum powder with a particle size of 25μm to 130g of dilute hydrochloric acid aqueous solution with a concentration of 10wt%, and stir continuously at 70℃ for 8h to prepare a clear and transparent aluminum sol. Step 2) Add 150g of triethanolamine to 250ml of deionized water and stir until dissolved to obtain an aqueous solution of triethanolamine. Then mix the aqueous solution of triethanolamine with 10g of oleic acid and stir continuously to obtain a clear solution. Finally, add the clear solution to the aluminum sol and stir thoroughly at a constant temperature of 80℃ to obtain a gel. Step 3) Drop the gel into an oil-ammonia column with a kerosene height of 25 cm, an ammonia water height of 50 cm, and an ammonia water concentration of 8 wt%, and let it form spheres. After aging for 2 hours, take out the formed gel spheres, wash them with deionized water, dry them in an oven at 90°C for 8 hours, and calcine them at 550°C for 2 hours to obtain a spherical alumina high-efficiency regenerator.

[0036] Example 3 A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Add 18g of aluminum powder with a particle size of 25μm to 130g of dilute hydrochloric acid aqueous solution with a concentration of 10wt%, and stir continuously at 70℃ for 8h to prepare a clear and transparent aluminum sol. Step 2) Add 150g of triethanolamine to 250ml of deionized water and stir until dissolved to obtain an aqueous solution of triethanolamine. Then mix the aqueous solution of triethanolamine with 3g of oleic acid and stir continuously to obtain a clear solution. Finally, add the clear solution to the aluminum sol and stir thoroughly at a constant temperature of 80℃ to obtain a gel. Step 3) Drop the gel into an oil-ammonia column with a kerosene height of 25 cm, an ammonia water height of 50 cm, and an ammonia water concentration of 8 wt%, and let it form spheres. After aging for 2 hours, take out the formed gel spheres, wash them with deionized water, dry them in an oven at 90°C for 8 hours, and calcine them at 550°C for 2 hours to obtain a spherical alumina high-efficiency regenerator.

[0037] Example 4 A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Add 18g of aluminum powder with a particle size of 25μm to 130g of dilute hydrochloric acid aqueous solution with a concentration of 10wt%, and stir continuously at 70℃ for 8h to prepare a clear and transparent aluminum sol. Step 2) Add 150g of triethanolamine to 250ml of deionized water and stir until dissolved to obtain an aqueous solution of triethanolamine. Then mix the aqueous solution of triethanolamine with 10g of stearic acid and stir continuously to obtain a clear solution. Finally, add the clear solution to the aluminum sol and stir thoroughly at a constant temperature of 80℃ to obtain a gel. Step 3) Drop the gel into an oil-ammonia column with a kerosene height of 50 cm, an ammonia water height of 50 cm, and an ammonia water concentration of 8 wt%, and let it form spheres. After aging for 4 hours, take out the formed gel spheres, wash them with deionized water, dry them in an oven at 90°C for 8 hours, and calcine them at 550°C for 3 hours to obtain a spherical alumina high-efficiency regenerator.

[0038] Example 5 A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Add 18g of aluminum powder with a particle size of 25μm to 130g of dilute hydrochloric acid aqueous solution with a concentration of 10wt%, and stir continuously at 70℃ for 8h to prepare a clear and transparent aluminum sol. Step 2) Add 150g of triethanolamine to 250ml of deionized water and stir until dissolved to obtain an aqueous solution of triethanolamine. Then mix the aqueous solution of triethanolamine with 10g of stearic acid and stir continuously to obtain a clear solution. Finally, add the clear solution to the aluminum sol and stir thoroughly at a constant temperature of 80℃ to obtain a gel. Step 3) Drop the gel into an oil-ammonia column with a kerosene height of 50 cm, an ammonia water height of 50 cm, and an ammonia water concentration of 8 wt%, and let it form spheres. After aging for 12 hours, take out the formed gel spheres, wash them with deionized water, dry them in an oven at 90°C for 12 hours, and calcine them at 550°C for 3 hours to obtain a spherical alumina high-efficiency regenerator.

[0039] Example 6 A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Add 18g of aluminum powder with a particle size of 25μm to 130g of dilute hydrochloric acid aqueous solution with a concentration of 10wt%, and stir continuously at 70℃ for 8h to prepare a clear and transparent aluminum sol. Step 2) Add 100g of triethanolamine to 250ml of deionized water and stir until dissolved to obtain an aqueous solution of triethanolamine. Then mix the aqueous solution of triethanolamine with 10g of stearic acid and stir continuously to obtain a clear solution. Finally, add the clear solution to the aluminum sol and stir thoroughly at a constant temperature of 80℃ to obtain a gel. Step 3) Drop the gel into an oil-ammonia column with a kerosene height of 25 cm, an ammonia water height of 50 cm, and an ammonia water concentration of 8 wt%, and let it form spheres. After aging for 2 hours, take out the formed gel spheres, wash them with deionized water, dry them in an oven at 90°C for 8 hours, and calcine them at 550°C for 2 hours to obtain a spherical alumina high-efficiency regenerator.

[0040] Example 7 A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Add 18g of aluminum powder with a particle size of 25μm to 130g of dilute hydrochloric acid aqueous solution with a concentration of 10wt%, and stir continuously at 70℃ for 8h to prepare a clear and transparent aluminum sol. Step 2) Add 130g of triethanolamine to 250ml of deionized water and stir until dissolved to obtain an aqueous solution of triethanolamine. Then mix the aqueous solution of triethanolamine with 10g of stearic acid and stir continuously to obtain a clear solution. Finally, add the clear solution to the aluminum sol and stir thoroughly at a constant temperature of 80℃ to obtain a gel. Step 3) Drop the gel into an oil-ammonia column with a kerosene height of 25 cm, an ammonia water height of 50 cm, and an ammonia water concentration of 8 wt%, and let it form spheres. After aging for 2 hours, take out the formed gel spheres, wash them with deionized water, dry them in an oven at 90°C for 8 hours, and calcine them at 550°C for 2 hours to obtain a spherical alumina high-efficiency regenerator.

[0041] Comparative Example 1 A method for preparing a highly efficient spherical alumina regenerator includes the following steps: Step 1) Add 18g of aluminum powder with a particle size of 25μm to 130g of dilute hydrochloric acid aqueous solution with a concentration of 10wt%, and stir continuously at 70℃ for 8h to prepare a clear and transparent aluminum sol. Step 2) Add 150g of triethanolamine to 250ml of deionized water and stir until dissolved to obtain an aqueous solution of triethanolamine. Then add the aqueous solution of triethanolamine to the aluminum sol and stir thoroughly at a constant temperature of 80℃ to obtain a gel. Step 3) Drop the gel into an oil-ammonia column with a kerosene height of 25 cm, an ammonia water height of 50 cm, and an ammonia water concentration of 8 wt%, and let it form spheres. After aging for 2 hours, take out the formed gel spheres, wash them with deionized water, dry them in an oven at 90°C for 8 hours, and calcine them at 550°C for 2 hours to obtain a spherical alumina high-efficiency regenerator.

[0042] Performance testing Average particle size: Randomly select more than 30 representative particles as samples and measure their diameter with a vernier caliper with an accuracy of 0.02 mm. The average particle size D (mm) = (D1 + D2 + ... + Dn) / n; where D1, D2 ... Dn are the diameters (mm) of each particle in the sample, and n is the total number of particles in the sample, in units of particles.

[0043] Strength: The strength shall be determined using a particle strength tester according to the method specified in HG / T 2782-2024.

[0044] Wear rate: The wear rate was determined using an abrasion tester according to the method specified in HG / T 3927-2020.

[0045] Specific surface area and pore volume: Weigh approximately 0.2g of sample, accurate to 0.0002g, and place it in a sample tube; turn on the static nitrogen adsorption instrument, install the sample tube on the pretreatment clamp, cover it with a heating pack, heat to 250℃, and heat for 2 hours. Move the sample tube to the measurement position, complete the analysis operation according to the instrument requirements, and read the results of specific surface area and pore volume. Take the arithmetic mean of the parallel determination results as the measurement result. The relative deviation between two parallel determination results should not exceed 5%.

[0046] Sphericity: Randomly select more than 10 representative particle samples and measure them with a vernier caliper with an accuracy of 0.02 mm. Measure the longest diameter d1 and the shortest diameter d2 of each particle. The sphericity of a single particle is calculated as Ø = (1 - (d1 - d2) / D) × 100%. Finally, take the average sphericity of all particles in the sample as the sphericity result of the batch of samples.

[0047] The test data are shown in Table 1.

[0048] Table 1. Detection data of Examples 1-7 and Comparative Example 1 Average particle size Strength (N) Wear rate (%) <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> Sphericity (%) Example 1 2.1 60 0.3 255 0.47 96 Example 2 2.0 64 0.4 249 0.46 96 Example 3 1.8 67 0.2 223 0.43 95 Example 4 2.1 58 0.3 251 0.45 97 Example 5 2.0 59 0.3 247 0.45 98 Example 6 1.9 56 0.5 237 0.44 94 Example 7 2.0 58 0.4 245 0.45 95 Comparative Example 1 1.8 55 0.5 212 0.40 95 Referring to Examples 1-3 and Comparative Example 1 and in conjunction with Table 1, it can be seen that, compared with Comparative Example 1, Examples 1-3 all achieved varying degrees of improvement in strength, wear rate, specific surface area, and pore volume sphericity.

[0049] The reason for this is that, in Examples 1-3, a clear solution obtained by adding triethanolamine aqueous solution and carboxylic acid mixture to aluminum sol was obtained. By adjusting the chain length of carboxylic acid, the specific surface area and pore volume of the synthesized spherical alumina were controlled. Triethanolamine can form a stable complex with aluminum ions. At the same time, excess triethanolamine will produce an alkaline pH value, which helps the controlled hydrolysis of the complex in the early stage. This leads to better sphericity, lower wear rate, better strength, better specific surface area and better pore volume of the spherical alumina.

[0050] Of Examples 1-3, Example 3 has the smallest average particle size, the highest strength, and the lowest wear rate; Example 1 has the highest specific surface area, the highest pore volume, and the highest sphericity. Therefore, when selecting carboxylic acids, stearic acid or lactic acid can be selected according to actual needs.

[0051] Referring to Examples 1, 4, and 5 and in conjunction with Table 1, it can be seen that compared to Example 1, the average particle size, strength, and wear rate of Examples 4-5 remained essentially unchanged. However, the specific surface area and pore volume of Examples 4-5 decreased significantly, while the sphericity increased significantly. This indicates that during the oil-ammonia column molding process, with the extension of aging and drying time, the specific surface area and pore volume of spherical alumina gradually decrease, while the sphericity gradually increases.

[0052] Referring to Examples 1, 6, and 7 and in conjunction with Table 1, it can be seen that, compared to Example 1, the average particle size, strength, specific surface area, pore volume, and sphericity of Examples 6-7 all decreased to varying degrees, while the wear rate of Examples 6-7 also increased to varying degrees. This indicates that with the increase of triethanolamine content, spherical alumina will possess superior average particle size, strength, specific surface area, pore volume, sphericity, and wear resistance.

[0053] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a highly efficient spherical alumina regenerator, characterized in that, Includes the following steps: Step 1) Hydrochloric acid reacts with aluminum to prepare aluminum sol; Step 2) Mix the amine with the carboxylic acid to obtain a clear solution; add the clear solution to the aluminum sol to obtain a gel; the carboxylic acid is one or more of stearic acid, oleic acid and lactic acid; Step 3) The gel is shaped into spheres using the oil-ammonia column molding method, followed by aging, washing, drying, and calcination to obtain a spherical alumina high-efficiency regenerator.

2. The method for preparing the spherical alumina high-efficiency regenerator according to claim 1, characterized in that: The carboxylic acid is stearic acid or lactic acid.

3. The method for preparing the spherical alumina high-efficiency regenerator according to claim 1, characterized in that: The amount of carboxylic acid added is 0-10% of the mass of the aluminum sol.

4. The method for preparing the spherical alumina high-efficiency regenerator according to claim 1, characterized in that: The amine is an aqueous solution of triethanolamine, and the amount of the amine added is 10-60% of the mass of the aluminum sol.

5. The method for preparing the spherical alumina high-efficiency regenerator according to claim 4, characterized in that: The amount of amine added is 50% of the mass of aluminum sol.

6. The method for preparing the spherical alumina high-efficiency regenerator according to claim 1, characterized in that, Step 1) involves adding dilute hydrochloric acid to aluminum powder, stirring, and maintaining the system temperature at 50-70℃ to obtain a transparent aluminum sol.

7. The method for preparing the spherical alumina high-efficiency regenerator according to claim 1, characterized in that: The aluminum powder has a particle size of <150μm and a purity of >99.9wt%.

8. The method for preparing the spherical alumina high-efficiency regenerator according to claim 1, characterized in that: In step 3), the oil phase used in the oil-ammonia column forming method for forming spheres is one of vacuum pump oil, kerosene, or diesel oil, and the oil phase height is 20-100cm. And / or the ammonia phase used in the oil-ammonia column forming method is ammonia water, the ammonia water concentration of the ammonia phase is 5-20wt%, and the height is 20-100cm.

9. The method for preparing the spherical alumina high-efficiency regenerator according to claim 1, characterized in that: In step 3), the aging temperature is 10-30℃, and the aging time is 2-24 hours; and / or drying temperature 90-150℃, drying time 2-12h; And / or the roasting temperature is 400-600℃, and the roasting time is 2-12h.

10. The application of the spherical alumina high-efficiency regenerator according to any one of claims 1-9, characterized in that: The spherical alumina high-efficiency regenerator is suitable for regenerating catalysts from anthraquinone degradation products.