Columnar coal-based activated carbon prepared from weakly caking coal and preparation method of columnar coal-based activated carbon

Abstract

The invention discloses columnar coal-based activated carbon prepared from coal with weak caking property and a preparation method of the columnar coal-based activated carbon. The preparation method of the columnar coal-based activated carbon provided by the invention comprises the following steps: 1) grinding raw coal to obtain raw coal; (2) adding an adhesive and water into the raw coal, and stirring and forming to obtain a columnar material; and 3) drying, carbonizing and activating the columnar material to obtain the columnar coal-based activated carbon, the raw coal contains coal with weak caking property; the adhesive is a compound of urea and starch, or a compound of urea, starch and ammonium bicarbonate, or vegetable oil. The columnar coal-based activated carbon prepared by the preparation method disclosed by the invention is excellent in performance, and has relatively high iodine value, abrasive resistance and CCl4 adsorption rate; meanwhile, the method has the advantages of simple operation, low cost, environment-friendly production and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of activated carbon production, and specifically relates to a columnar coal-based activated carbon prepared from weakly caking coal and a preparation method thereof. Background Art

[0002] As an adsorption material with excellent adsorption performance, activated carbon is widely used in various fields such as environmental protection, petrochemicals, national defense, aerospace, food, medicine and daily life. At present, the raw materials for preparing activated carbon mainly include coal, fruit shells, fruit cores and wood. Compared with other raw materials, coal is widely available and cheap, and coal-based activated carbon has high mechanical strength and good chemical stability. Therefore, considering the source of raw materials, cost and product performance, coal has become the main raw material for preparing coal-based activated carbon.

[0003] The preparation process of coal-based activated carbon mainly includes grinding, kneading, carbonization, activation and other processes. In theory, all coal can be used to produce activated carbon, but not all coal can be used to produce high-quality activated carbon. In industry, most of the coal with high metamorphic degree and no adhesion is used as raw material to produce activated carbon. Although the obtained coal-based activated carbon has good performance, the cost is relatively high.

[0004] Weakly caking coal (abbreviated as weakly caking coal) belongs to coal with low or medium coalification degree, and its caking index is below 80. It generally has the characteristics of low ash, low sulfur and high volatile matter, but it is cheap. CN110877909A discloses a method for preparing coal-based columnar activated carbon using low-volatile weakly caking coal (volatile matter ≤15%), but the strength value of the columnar activated carbon obtained by this method is 80-93 and the specific surface area is 800-1000m 2 / g, iodine value is 800-1000mg / g, carbon tetrachloride adsorption value is 50-70%, and the comprehensive performance is relatively low.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a columnar coal-based activated carbon prepared from weakly adhesive coal and a preparation method thereof. The columnar coal-based activated carbon has excellent performance, relatively high iodine value, wear resistance and CCl4 adsorption rate, and the preparation method has the advantages of simple operation, low cost, environmentally friendly production, etc., which is more conducive to popularization and use.

[0007] To achieve the above object, the present invention provides the following technical solutions: In a first aspect, the present invention provides a columnar coal-based activated carbon, which is prepared from the following raw materials in parts by weight: raw coal, a binder; The raw coal is selected from one or more of weakly caking coal, weakly caking coal and anthracite blended coal, and weakly caking coal and semi-coke blended coal; The binder is selected from a compound of urea and starch, a compound of urea, starch and ammonium bicarbonate, or one or more of vegetable oils.

[0008] The present invention selects a specific binder for use in combination with weakly adhesive coal, which can significantly improve the iodine value, wear resistance and CCl4 adsorption rate of weakly adhesive coal-based columnar coal-based activated carbon, thereby reducing the raw material composition of the columnar coal-based activated carbon and improving its performance indicators, achieving unexpected technical effects.

[0009] In the present invention, the indicators of the weakly adhesive coal are as follows: moisture ≤12%, ash ≤10%, volatile matter 28.0-50.0%, which belongs to high-volatile weakly adhesive coal, but is cheaper. Using it as raw coal to prepare high-quality columnar coal-based activated carbon can greatly reduce its production cost, but the technical difficulty is also increased accordingly.

[0010] In the present invention, the mass fraction of weakly cohesive coal in the raw coal reaches 70-100%.

[0011] Specifically, the raw coal may all be weakly adhesive coal; or a combination of weakly adhesive coal and anthracite, or a combination of weakly adhesive coal and lignite, wherein the mass fraction of the weakly adhesive coal is 70% to 90%, preferably 75 to 85%, such as 80%.

[0012] In the present invention, when the binder is a compound of urea and starch, the mass fraction of the urea in the binder is 5-40%, preferably 10-30%; when the binder is a compound of urea, starch and ammonium bicarbonate, the mass fraction of the urea in the binder is 5-25%, preferably 10-20%, and the mass fraction of the starch in the binder is 65-85%, preferably 70-80%.

[0013] In the present invention, the vegetable oil is selected from one or more of linseed oil, castor oil and coconut oil; when the vegetable oil is a compound of castor oil and linseed oil, the mass ratio of the castor oil to the linseed oil is 1:(1-2); When the vegetable oil is a compound of castor oil and coconut oil, the mass ratio of the castor oil to the coconut oil is 1:(1-2); When the vegetable oil is a compound of linseed oil and coconut oil, the mass ratio of the linseed oil to the coconut oil is 1:(1-2); When the binder is a compound of linseed oil, castor oil and coconut oil, the mass ratio of the linseed oil, the castor oil and the coconut oil is 1:(1-2):1.

[0014] In the present invention, the amount of the binder added is carried out according to the following operation: When the binder is a compound of urea and starch, or a compound of urea, starch and ammonium bicarbonate, the amount of the binder used is 3-7% of the mass of the raw coal; specifically, it can be divided into 3%, 5% and 7%, preferably 5%.

[0015] When the binder is vegetable oil, the amount of the binder is 20-50% of the mass of the raw coal, specifically 20%, 30%, 40% and 50%, preferably 30-40%.

[0016] In a second aspect, the present invention also provides a method for preparing the above-mentioned columnar coal-based activated carbon, comprising the following steps: 1) Grind the raw coal, add binder and water, stir and shape to obtain columnar material; 2) Drying, carbonizing and activating the columnar material obtained in step 1) to obtain the columnar coal-based activated carbon.

[0017] In the present invention, in step 1), the grinding is to grind the raw coal to a particle size of 200 mesh to 325 mesh, specifically 200 mesh, 250 mesh or 325 mesh.

[0018] In the present invention, in step 1), the amount of water added is carried out according to the following operation: When the binder is a compound of urea and starch, or a compound of urea, starch and ammonium bicarbonate, the amount of water added is 30-45% of the mass of the raw coal; preferably 35-40%; When the binder is vegetable oil, the amount of water added is 5-20% of the mass of the raw coal, which can be specifically divided into 5%, 10%, 15% and 20%, preferably 10-15%.

[0019] In the present invention, in step 1), the diameter of the columnar material is Φ0.5-5 mm, specifically Φ1 mm, Φ3 mm and Φ5 mm.

[0020] In the present invention, in step 2), the carbonization conditions are: temperature of 500-800°C, specifically 500°C, 600°C, 700°C and 800°C, etc., preferably 600-700°C; time of 30-45min, specifically 30min, 45min; heating rate of 5-8°C / min, specifically 5°C / min, 6°C / min and 8°C / min.

[0021] In the present invention, in step 2), the activation conditions are: temperature of 800-950°C, specifically 800°C, 850°C, 900°C and 950°C; time of 2-4h, specifically 2h, 3h, 3.5h and 4h, preferably 3-4h; water / carbon ratio of 1.5-2.

[0022] In the present invention, the activation medium used in the activation is selected from at least one of water vapor, carbon dioxide and air; When the activation medium is a mixture of water vapor and carbon dioxide, the mass ratio of the water vapor to the carbon dioxide is 1:(1-2); When the activation medium is a mixture of water vapor and air, the mass ratio of the water vapor to the air is 1:(1-2); When the activation medium is a mixture of carbon dioxide and air, the mass ratio of the carbon dioxide to the air is 1:(1-2); When the activation medium is a mixture of water vapor, carbon dioxide and air, the mass ratio of the water vapor, the carbon dioxide and the air is (1-2): 1:1.

[0023] Compared with the prior art, the present invention has the following beneficial effects: The preparation method of columnar coal-based activated carbon provided by the present invention not only achieves the purpose of preparing columnar coal-based activated carbon with weakly adhesive coal as raw material, reducing production costs, and ensuring process safety and environmental protection, but the obtained columnar coal-based activated carbon also has the advantages of relatively higher iodine value, wear resistance and CCl4 adsorption rate. Its iodine value is as high as 1354 mg / g, the wear resistance is as high as 98.8%, and the CCl4 adsorption rate is as high as 89.21%. DETAILED DESCRIPTION

[0024] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments.

[0025] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0026] Unless otherwise specified, the reagents, materials, instruments, etc. used in the following examples can be obtained from commercial sources.

[0027] Example 1. Preparation of columnar coal-based activated carbon Here are the steps: (1) First, grind the raw coal (weakly cohesive coal) to a particle size of 325 mesh, add a binder (urea and starch in a mass ratio of 1:9) accounting for 5% of the coal powder during the mixing process, and then add water accounting for 35% of the coal powder. After all the raw materials are fully mixed, use a four-column hydraulic press to form the material into a Φ5mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material. The activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 1.5, and the activation time is 120 min.

[0028] Example 2: Preparation of columnar coal-based activated carbon (1) First, grind the raw coal (weakly cohesive coal) to a particle size of 325 mesh, add castor oil accounting for 30% of the mass of the coal powder, and add water accounting for 10% of the mass of the coal powder during the mixing process. After all the raw materials are fully mixed, use a four-column hydraulic press to form the material into a Φ5mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material, the activation temperature is set to 850 °C, the activation medium is water vapor, the water / carbon ratio is 2, and the activation time is 240 min.

[0029] Example 3: Preparation of columnar coal-based activated carbon (1) First, grind the raw coal (weakly cohesive coal) to a particle size of 325 mesh, add castor oil accounting for 30% of the mass of the coal powder, and add water accounting for 10% of the mass of the coal powder during the mixing process. After all the raw materials are fully mixed, use a four-column hydraulic press to form the material into a Φ5mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material, the activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 2, and the activation time is 180 min.

[0030] Example 4: Preparation of columnar coal-based activated carbon (1) First, grind the raw coal (weakly cohesive coal) to a particle size of 325 mesh, add castor oil accounting for 30% of the mass of the coal powder, and add water accounting for 10% of the mass of the coal powder during the mixing process. After all the raw materials are fully mixed, use a four-column hydraulic press to form the material into a Φ5mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material. The activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 2, and the activation time is 210 min.

[0031] Example 5: Preparation of columnar coal-based activated carbon (1) First, grind the raw coal (weakly cohesive coal) to a particle size of 325 mesh, add castor oil accounting for 30% of the mass of the coal powder, and add water accounting for 10% of the mass of the coal powder during the mixing process. After all the raw materials are fully mixed, use a four-column hydraulic press to form the material into a Φ3mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material, the activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 2, and the activation time is 180 min.

[0032] Example 6: Preparation of columnar coal-based activated carbon (1) First, grind the raw coal (weakly cohesive coal) to a particle size of 325 mesh, add castor oil accounting for 30% of the mass of the coal powder, and add water accounting for 10% of the mass of the coal powder during the mixing process. After all the raw materials are fully mixed, use a four-column hydraulic press to form the material into a Φ3mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material. The activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 2, and the activation time is 210 min.

[0033] Example 7: Preparation of columnar coal-based activated carbon (1) First, the raw coal (weakly cohesive coal and semi-coke) is ground into powder respectively, and the particle size is 325 mesh. The weakly cohesive coal and semi-coke are mixed into a total coal powder at a mass ratio of 8:2. During the stirring process, castor oil accounting for 20% of the mass of the coal powder and water accounting for 10% of the mass of the coal powder are added. After all the raw materials are fully mixed, the materials are formed into Φ5 mm columns using a four-column hydraulic press; (2) Dry the formed material at room temperature for 24 h; carbonize the dried material, set the final carbonization temperature of the material to 600 °C, and keep it at 600 °C for 30 min, and control the material heating rate at 5 °C / min; (3) Activate the carbonized material, the activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 2, and the activation time is 180 min.

[0034] Example 8: Preparation of columnar coal-based activated carbon (1) First, the raw coal (weakly cohesive coal and anthracite) was ground into powder respectively, and the particle size was 325 mesh. The weakly cohesive coal and anthracite were mixed into a total coal powder at a mass ratio of 8:2. During the mixing process, castor oil accounting for 20% of the mass of the coal powder and water accounting for 10% of the mass of the coal powder were added. After all the raw materials were fully mixed, the materials were formed into Φ5 mm columns using a four-column hydraulic press; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material, the activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 2, and the activation time is 180 min.

[0035] Example 9: Preparation of columnar coal-based activated carbon (1) First, grind the raw coal (weakly cohesive coal) to a particle size of 325 mesh; add a binder (composed of urea, starch and ammonium bicarbonate in a mass ratio of 1:8:1) accounting for 5% of the mass of the coal powder to the coal powder under stirring conditions, and then add water accounting for 35% of the mass of the coal powder. After fully mixing, use a four-column hydraulic press to form the material into a Φ5 mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material. The activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 1.5, and the activation time is 120 min.

[0036] Example 10: Preparation of columnar coal-based activated carbon (1) Grinding raw coal (weakly cohesive coal) to a particle size of 325 mesh; adding a binder (composed of linseed oil and castor oil in a mass ratio of 1:1) accounting for 30% of the mass of the coal powder to the coal powder under stirring conditions, and then adding water accounting for 10% of the mass of the coal powder, and after fully mixing, using a four-column hydraulic press to form the material into a Φ5 mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material, the activation temperature is set to 900 °C, the activation medium is water vapor, the water / carbon ratio is 2, and the activation time is 180 min.

[0037] Example 11: Preparation of columnar coal-based activated carbon (1) First, grind the raw coal (weakly cohesive coal) to a particle size of 325 mesh, add a binder (urea and starch in a mass ratio of 1:9) accounting for 5% of the coal powder mass during the mixing process, and add water accounting for 35% of the coal powder mass. After all the raw materials are fully mixed, use a four-column hydraulic press to form the material into a Φ5mm column; (2) Dry the formed material at room temperature for 24 hours; carbonize the dried material, set the final carbonization temperature of the material to 600°C, and keep it at 600°C for 30 minutes, and control the material heating rate at 5°C / min; (3) Activate the carbonized material, set the activation temperature to 900 °C, use the activation medium as a mixture of water vapor and carbon dioxide (mass ratio is 1:1), and the water / carbon ratio is 1.5, and the activation time is 120 min.

[0038] Test Case The coal-based activated carbon obtained in Examples 1-11 was tested.

[0039] At the same time, Example 1 in CN110877909A was used as a comparative example.

[0040] The test method is as follows: Determination method of iodine value of coal-based activated carbon: iodine value determination method specified in GB / T 7702.7-2023.

[0041] Determination method of wear resistance: Determination method of wear resistance specified in GB / T 7702.3-2008.

[0042] Method for determining carbon tetrachloride (CCl4) adsorption rate: The method for determining CCl4 adsorption rate specified in GB / T 7702.13-1997.

[0043] Table 1 Properties of coal-based activated carbon

[0044] It can be seen from the results in Table 1 that, compared with CN110877909A, the iodine value of the coal-based activated carbons prepared in Examples 1-11 is higher than 1000 mg / g, the abrasion resistance is higher than 93%, and the CCl4 adsorption rate is higher than 60%. This shows that the comprehensive performance of the coal-based activated carbon provided by the present invention is significantly improved. At the same time, because the raw materials do not contain asphalt, the preparation method is more environmentally friendly and the process is simpler.

[0045] Although the present invention has been described in detail above with general descriptions and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements may be made thereto based on the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims

1. A columnar coal-based activated carbon, prepared from the following raw materials in parts by weight: raw coal, a binder; The raw coal is selected from one or more of weakly caking coal, weakly caking coal and anthracite blended coal, and weakly caking coal and semi-coke blended coal; The binder is selected from a compound of urea and starch, a compound of urea, starch and ammonium bicarbonate, or one or more of vegetable oils.

2. The columnar coal-based activated carbon according to claim 1, characterized in that: The indicators of the weakly cohesive coal are as follows: moisture ≤ 12%, ash ≤ 10%, volatile matter 28.0-50.0%; The mass fraction of weakly cohesive coal in the raw coal is 70-100%.

3. The columnar coal-based activated carbon according to claim 1 or 2, characterized in that: When the binder is a compound of urea and starch, the mass fraction of urea in the binder is 5-40%; When the binder is a compound of urea, starch and ammonium bicarbonate, the mass fraction of the urea in the binder is 5-25%, and the mass fraction of the starch in the binder is 65-85%.

4. The columnar coal-based activated carbon according to claim 1 or 2, characterized in that: The vegetable oil is selected from one or more of linseed oil, castor oil and coconut oil; When the vegetable oil is a compound of castor oil and linseed oil, the mass ratio of the castor oil to the linseed oil is 1:(1-2); When the vegetable oil is a compound of castor oil and coconut oil, the mass ratio of the castor oil to the coconut oil is 1:(1-2); When the vegetable oil is a compound of linseed oil and coconut oil, the mass ratio of the linseed oil to the coconut oil is 1:(1-2); When the binder is a compound of linseed oil, castor oil and coconut oil, the mass ratio of the linseed oil, the castor oil and the coconut oil is 1:(1-2):

1.

5. The columnar coal-based activated carbon according to any one of claims 1 to 3, characterized in that: The amount of the binder added is carried out according to the following operation: When the binder is a compound of urea and starch, or a compound of urea, starch and ammonium bicarbonate, the amount of the binder is 3-7% of the mass of the raw coal; When the binder is vegetable oil, the amount of the binder used is 20-50% of the mass of the raw coal.

6. The method for preparing columnar coal-based activated carbon according to any one of claims 1 to 5, comprising the following steps: 1) Grind the raw coal, add binder and water, stir and shape to obtain columnar material; 2) Drying, carbonizing and activating the columnar material obtained in step 1) to obtain the columnar coal-based activated carbon.

7. The preparation method according to claim 6, characterized in that: In step 1), the grinding is to grind the raw coal to a particle size of 200-325 mesh.

8. The preparation method according to claim 6 or 7, characterized in that: In step 1), the amount of water added is carried out according to the following operation: When the binder is a compound of urea and starch, or a compound of urea, starch and ammonium bicarbonate, the amount of water added is 30-45% of the mass of the raw coal; When the binder is vegetable oil, the amount of water added is 5-20% of the mass of the raw coal.

9. The preparation method according to any one of claims 6 to 8, characterized in that: In step 2), the carbonization conditions are: temperature of 500-800°C, time of 30-45 min, and heating rate of 5-8°C / min; The activation conditions are: temperature of 800-950° C., time of 2-4 hours, and water / carbon ratio of 1.5-2.

10. The preparation method according to claim 9, characterized in that: The activation medium used in the activation is at least one of water vapor, carbon dioxide and air; When the activation medium is a mixture of water vapor and carbon dioxide, the mass ratio of the water vapor to the carbon dioxide is 1:(1-2); When the activation medium is a mixture of water vapor and air, the mass ratio of the water vapor to the air is 1:(1-2); When the activation medium is a mixture of carbon dioxide and air, the mass ratio of the carbon dioxide to the air is 1:(1-2); When the activation medium is a mixture of water vapor, carbon dioxide and air, the mass ratio of the water vapor, the carbon dioxide and the air is (1-2): 1:1.

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