Composite semi-coke powder and preparation method thereof

Abstract

The invention provides composite semi-coke powder and a preparation method thereof, and belongs to the technical field of semi-coke powder. Comprising the following steps: S1, adding activated carbon into a Tris-HCl solution, adding tannic acid, heating and stirring for reaction, centrifuging, washing and drying to obtain modified activated carbon; s2, the semi-coke powder with the particle size larger than 3 mm is subjected to ball milling, semi-coke particles with the fine particle size smaller than 100 meshes are collected, screen residues are mixed with the next batch of semi-coke powder with the particle size larger than 3 mm, ball milling is conducted again multiple times, and the semi-coke powder with the fine particle size is obtained; s3, adding the modified activated carbon and the fine-particle-size semi-coke powder into water, stirring, mixing, adsorbing, centrifuging, washing and drying to obtain a compound; and S4, drying and crushing straws, adding the crushed straws into water, adding the compound, uniformly stirring and mixing, centrifuging, washing, drying and calcining to obtain the composite semi-coke powder. The prepared composite semi-coke powder effectively overcomes the defects of traditional semi-coke powder and has wide application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of blue carbon powder, and in particular to a composite blue carbon powder and a preparation method thereof. Background Art

[0002] Semi-coke powder is a powdered substance formed by pulverizing semi-coke (also known as "semi-coke"). Semi-coke is a solid carbonaceous product extracted from low-rank coal (such as lignite and long-flame coal) through a medium- to low-temperature dry distillation process (typically pyrolysis temperatures of 600-800°C). It has a high carbon content and a high calorific value, while containing lower sulfur and ash than ordinary coal. Its environmental friendliness and well-developed pore structure contribute to its high reaction efficiency in metallurgy, chemical engineering, and other fields.

[0003] However, powdered lignite may generate dust pollution during transportation and storage, and may clump after absorbing moisture, affecting its efficiency. At the same time, lignite also has some defects: poor ignition performance, mechanical properties and compressive resistance.

[0004] Chinese patent publication CN 111961772 A discloses a method for preparing and applying modified semi-coke, including: preparing semi-coke powder, sampling and analyzing different semi-coke raw materials, collecting and reanalyzing amplified samples of the preliminarily selected semi-coke raw materials, determining a variety of semi-coke raw materials based on production requirements, and then proportioning the raw materials based on parameters obtained from the analysis of the amplified samples. The proportioned semi-coke raw materials are then mixed and subjected to static pressure crushing in a reformer. The crushed semi-coke product from the reformer is then sieved to meet particle size distribution requirements, resulting in a modified semi-coke having a Hardgrove grindability index greater than 53. However, this modified semi-coke still suffers from dust pollution and agglomeration problems, and its compressive strength has not been significantly improved. Summary of the Invention

[0005] The purpose of the present invention is to propose a composite blue carbon powder and a preparation method thereof. Through the synergistic effect of multiple steps, combined with physical modification and chemical composite technology, the defects of traditional blue carbon powder (dust pollution, easy agglomeration, poor ignition performance, insufficient mechanical properties, etc.) are effectively overcome, and significant technical effects are brought about.

[0006] The technical solution of the present invention is achieved as follows: The present invention provides a method for preparing composite blue carbon powder, comprising the following steps: S1. Preparation of modified activated carbon: Activated carbon was added to a Tris-HCl solution, tannic acid was added, the reaction was heated with stirring, centrifuged, washed, and dried to obtain modified activated carbon; S2. Ball milling of semi-coal powder: Semi-coal powder with a particle size greater than 3 mm is ball milled, and fine-particle size semi-coal particles below 100 mesh are collected. The sieve residue is mixed with the next batch of semi-coal powder with a particle size greater than 3 mm and ball milled again multiple times to obtain fine-particle size semi-coal powder; S3. Composite: Modified activated carbon and fine-grained blue carbon powder were added to water, stirred and mixed for adsorption, centrifuged, washed, and dried to obtain a composite; S4. Calcination: Dry the straw, crush it, add it into water, add the compound, stir and mix it evenly, centrifuge it, wash it, dry it, and calcine it to obtain the composite blue carbon powder.

[0007] As a further improvement of the present invention, the pH value of the Tris-HCl solution in step S1 is 8.5-9.5.

[0008] As a further improvement of the present invention, the mass ratio of the activated carbon to tannic acid in step S1 is 10:3-5.

[0009] As a further improvement of the present invention, the temperature of the heating and stirring reaction in step S1 is 50-60° C. and the time is 2-4 hours.

[0010] As a further improvement of the present invention, the ball milling time in step S2 is 1-3 hours.

[0011] As a further improvement of the present invention, the mass ratio of the modified activated carbon to the fine-particle blue charcoal powder in step S3 is 12-15:8-10.

[0012] As a further improvement of the present invention, the time for stirring, mixing and adsorption in step S3 is 30-50 minutes.

[0013] As a further improvement of the present invention, the straw in step S4 is at least one of corn straw, rice straw, and sorghum straw.

[0014] As a further improvement of the present invention, in step S4, the mass ratio of the straw to the composite is 5-8:10-15, the calcination temperature is 700-800° C., and the calcination time is 3-5 h.

[0015] The present invention further protects a composite blue carbon powder obtained by the above-mentioned preparation method.

[0016] The present invention has the following beneficial effects: The present invention compounds blue charcoal powder with modified activated carbon. The activated carbon particles adsorb or physically wrap the surface of the blue charcoal powder, and the surface is coated with a layer of straw and then carbonized to form a "core-shell" structure, which reduces the directly exposed surface area of the blue charcoal powder and inhibits dust emission.

[0017] When the modified activated carbon of the present invention is combined with blue charcoal powder, its developed pore structure can absorb moisture from the environment, reducing the chance of moisture directly contacting the blue charcoal powder, thereby inhibiting agglomeration. Furthermore, the cellulose / lignin in the straw forms a carbon fiber skeleton after calcination, which combines with the blue charcoal powder to form a three-dimensional network structure, enhancing the overall mechanical strength. At high temperatures, SiO2 and CaO in the straw ash can form a silicate cementing phase, strengthening the bonding between particles and improving compressive resistance.

[0018] The present invention uses a "modification-compounding-calcination" series process to simultaneously improve the environmental protection, mechanical properties and combustion characteristics of blue carbon powder. The introduction of straw reduces the cost of raw materials, and the process is compatible with low-rank coal and agricultural waste, making it suitable for large-scale production. Composite blue carbon powder can replace traditional coke for calcium carbide furnaces, blast furnace injection, or be used as an environmentally friendly adsorbent for sewage treatment. DETAILED DESCRIPTION

[0019] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0020] Example 1 This embodiment provides a method for preparing composite blue carbon powder, comprising the following steps: S1. Preparation of modified activated carbon: 10 g of activated carbon was added to 200 mL of Tris-HCl solution (pH 8.5), 3 g of tannic acid was added, and the mixture was heated to 50°C with stirring for 2 h. The mixture was centrifuged, washed, and dried to obtain modified activated carbon. S2. Ball milling of semi-coal powder: Semi-coal powder with a particle size greater than 3 mm was ball milled for 1 hour. The fine-particle size of semi-coal particles below 100 mesh was collected, the remaining particles were mixed with the next batch of semi-coal powder with a particle size greater than 3 mm, and the mixture was ball milled again multiple times to obtain fine-particle size semi-coal powder. S3 composite: 12g of modified activated carbon and 8g of fine-particle blue carbon powder were added to 200mL of water, stirred and adsorbed for 30min, centrifuged, washed, and dried to obtain a composite; S4. Calcination: 5 g of sorghum straw was dried and crushed, added to 250 mL of water, and 10 g of the composite was added. The mixture was stirred for 15 minutes, centrifuged, washed, dried, and calcined at 700°C for 3 hours to obtain composite semi-coke powder.

[0021] Example 2 This embodiment provides a method for preparing composite blue carbon powder, comprising the following steps: S1. Preparation of modified activated carbon: 10 g of activated carbon was added to 200 mL of Tris-HCl solution (pH 9.5), 5 g of tannic acid was added, and the mixture was heated to 60°C with stirring for 4 h. The mixture was centrifuged, washed, and dried to obtain modified activated carbon. S2. Ball milling of semi-coal powder: Semi-coal powder with a particle size greater than 3 mm was ball milled for 3 h, and fine semi-coal particles with a particle size of less than 100 mesh were collected. The remaining particles were mixed with the next batch of semi-coal powder with a particle size greater than 3 mm and ball milled again multiple times to obtain fine semi-coal powder; S3 composite: 15g of modified activated carbon and 10g of fine-particle blue carbon powder were added to 200mL of water, stirred and adsorbed for 50min, centrifuged, washed, and dried to obtain a composite; S4. Calcination: 8 g of rice straw was dried and crushed, added to 250 mL of water, and 15 g of the composite was added. The mixture was stirred for 15 minutes, centrifuged, washed, dried, and calcined at 800°C for 5 hours to obtain composite semi-carbon powder.

[0022] Example 3 This embodiment provides a method for preparing composite blue carbon powder, comprising the following steps: S1. Preparation of modified activated carbon: 10 g of activated carbon was added to 200 mL of Tris-HCl solution (pH 9), 4 g of tannic acid was added, and the mixture was heated to 55°C with stirring for 3 h. The mixture was centrifuged, washed, and dried to obtain modified activated carbon. S2. Ball milling of semi-coal powder: Semi-coal powder with a particle size greater than 3 mm was ball milled for 2 h, and fine semi-coal particles with a particle size of less than 100 mesh were collected. The remaining particles were mixed with the next batch of semi-coal powder with a particle size greater than 3 mm and ball milled again multiple times to obtain fine semi-coal powder; S3 composite: 13g of modified activated carbon and 9g of fine-particle blue carbon powder were added to 200mL of water, stirred and adsorbed for 40min, centrifuged, washed, and dried to obtain a composite; S4. Calcination: 6 g of corn straw was dried and crushed, added to 250 mL of water, and 12 g of the composite was added. The mixture was stirred for 15 minutes, centrifuged, washed, dried, and calcined at 750°C for 4 hours to obtain composite semi-carbon powder.

[0023] Comparative Example 1 Compared with embodiment 3, the difference is that step S4 is not performed.

[0024] The details are as follows: S1. Preparation of modified activated carbon: 10 g of activated carbon was added to 200 mL of Tris-HCl solution (pH 9), 4 g of tannic acid was added, and the mixture was heated to 55°C with stirring for 3 h. The mixture was centrifuged, washed, and dried to obtain modified activated carbon. S2. Ball milling of semi-coal powder: Semi-coal powder with a particle size greater than 3 mm was ball milled for 2 h, and fine semi-coal particles with a particle size of less than 100 mesh were collected. The remaining particles were mixed with the next batch of semi-coal powder with a particle size greater than 3 mm and ball milled again multiple times to obtain fine semi-coal powder; S3. Compounding: Add 13 g of modified activated carbon and 9 g of fine-particle blue carbon powder into 200 mL of water, stir and mix, and adsorb for 40 minutes. Centrifuge, wash, and dry to obtain a composite, namely, composite blue carbon powder.

[0025] Comparative Example 2 Compared with embodiment 3, the difference is that step S1 is not performed.

[0026] The details are as follows: S1. Ball milling of semi-coal powder: Semi-coal powder with a particle size greater than 3 mm is ball milled for 2 hours. Fine semi-coal particles with a particle size of less than 100 mesh are collected, the remaining particles are mixed with the next batch of semi-coal powder with a particle size greater than 3 mm, and the mixture is ball milled again multiple times to obtain fine semi-coal powder. S2 composite: 13g activated carbon and 9g fine-particle blue carbon powder were added to 200mL of water, stirred and adsorbed for 40min, centrifuged, washed, and dried to obtain a composite; S3. Calcination: 6 g of corn straw was dried and crushed, added to 250 mL of water, and 12 g of the composite was added. The mixture was stirred for 15 minutes, centrifuged, washed, dried, and calcined at 750°C for 4 hours to obtain composite semi-carbon powder.

[0027] Comparative Example 3 Compared with embodiment 3, the difference is that step S2 is not performed.

[0028] The details are as follows: S1. Preparation of modified activated carbon: 10 g of activated carbon was added to 200 mL of Tris-HCl solution (pH 9), 4 g of tannic acid was added, and the mixture was heated to 55°C with stirring for 3 h. The mixture was centrifuged, washed, and dried to obtain modified activated carbon. S2 composite: 13g of modified activated carbon and 9g of blue carbon powder with a particle size of 20-40 mesh were added to 200mL of water, stirred and adsorbed for 40min, centrifuged, washed, and dried to obtain a composite; S3. Calcination: 6 g of corn straw was dried and crushed, added to 250 mL of water, and 12 g of the composite was added. The mixture was stirred for 15 minutes, centrifuged, washed, dried, and calcined at 750°C for 4 hours to obtain composite semi-carbon powder.

[0029] Test Example 1 The composite semi-coke powders prepared in Examples 1-3 and Comparative Examples 1-3 were molded at a molding pressure of 32 MPa and carbonized at 1000° C. for 2 h. The compressive strength of the molded cokes was analyzed. The results are shown in Table 1.

[0030] Table 1

[0031] It can be seen from the above table that the composite blue carbon powder prepared in Examples 1-3 of the present invention has better compressive strength.

[0032] Test Example 2 The thermogravimetric curve (TG curve) of the composite blue carbon powder prepared in Examples 1-3 and Comparative Examples 1-3 was tested, and the derivative thermogravimetric curve (DTG curve) was obtained after the first-order differentiation of the curve temperature T (or time t). The maximum combustion rate DTG was obtained by analysis. max , ignition index D i , the results are shown in Table 2.

[0033] Maximum burning rate DTG max : Reflects the intensity of sample combustion. It is the maximum value of the rate of change in the DTG curve, that is, the peak value of the curve. The larger the value, the more intense the combustion.

[0034] Ignition Index D i : Reflects the quality of the sample's ignition performance. Generally speaking, the better the sample's ignition performance, the larger the value.

[0035]

[0036] β is the heating rate, °C / s.

[0037] Table 2

[0038] It can be seen from the above table that the composite blue carbon powder prepared in Examples 1-3 of the present invention has better combustion performance, burns more violently and has better ignition performance.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing composite blue carbon powder, characterized in that: The following steps are involved: S1. Preparation of modified activated carbon: Activated carbon was added to a Tris-HCl solution, tannic acid was added, the reaction was heated with stirring, centrifuged, washed, and dried to obtain modified activated carbon; S2. Ball milling of semi-coal powder: Semi-coal powder with a particle size greater than 3 mm is ball milled, and fine-particle size semi-coal particles below 100 mesh are collected. The sieve residue is mixed with the next batch of semi-coal powder with a particle size greater than 3 mm and ball milled again multiple times to obtain fine-particle size semi-coal powder; S3. Composite: Modified activated carbon and fine-particle blue carbon powder were added to water, stirred and mixed for adsorption, centrifuged, washed, and dried to obtain a composite; S4. Calcination: Dry the straw, crush it, add it into water, add the compound, stir and mix it evenly, centrifuge it, wash it, dry it, and calcine it to obtain the composite blue carbon powder.

2. The preparation method according to claim 1, characterized in that The pH value of the Tris-HCl solution in step S1 is 8.5-9.

5.

3. The preparation method according to claim 1, characterized in that The mass ratio of the activated carbon to tannic acid in step S1 is 10:3-5.

4. The preparation method according to claim 1, characterized in that The temperature of the heating and stirring reaction in step S1 is 50-60° C. and the time is 2-4 hours.

5. The preparation method according to claim 1, characterized in that The ball milling time in step S2 is 1-3 hours.

6. The preparation method according to claim 1, characterized in that The mass ratio of the modified activated carbon to the fine-particle blue carbon powder in step S3 is 12-15:8-10.

7. The preparation method according to claim 1, characterized in that The stirring, mixing and adsorption time in step S3 is 30-50 minutes.

8. The preparation method according to claim 1, characterized in that The straw in step S4 is at least one of corn straw, rice straw, and sorghum straw.

9. The preparation method according to claim 1, characterized in that In step S4, the mass ratio of the straw to the composite is 5-8:10-15, the calcination temperature is 700-800° C., and the calcination time is 3-5 hours.

10. A composite blue carbon powder obtained by the preparation method according to any one of claims 1 to 9.

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