Coal blending method for improving coke quality by using carbon fibers and high-strength carbon fiber coke

Abstract

The invention discloses a coal blending method for improving coke quality by using carbon fibers and high-strength carbon fiber coke, and belongs to the technical field of metallurgical coke preparation. According to the coal blending method, carbon fibers are blended into a coal material during coal blending, and the blending amount of the carbon fibers is 0-0.2% of the mass of the coal material and is not 0. The high-strength carbon fiber coke comprises the following raw materials: carbon fibers and a basic coal sample in a mass ratio of (0.005-0.2): 1, wherein the basic coal sample comprises at least one of gas coal, fat coal, coking coal, 1 / 3 coking coal and lean coal. The carbon fibers are added in the coking and coal mixing stage, the crushing strength, abrasive resistance and post-reaction strength of the coke can be obviously improved, so that stable production is facilitated, and the ironmaking cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of metallurgical coke preparation, and particularly relates to a coal blending method for improving coke quality by utilizing carbon fiber and high-strength carbon fiber coke. Background Art

[0002] Coke is a solid fuel formed by a series of complex physical and chemical processes such as pyrolysis, polycondensation, solidification and shrinkage of coking coal under high temperature dry distillation. It is mainly used in the ironmaking industry and is an extremely important raw material in the blast furnace ironmaking process, playing the role of reducing agent, heating agent, carburizing agent and skeleton.

[0003] Coke strength has a crucial impact on blast furnace ironmaking efficiency and molten iron quality. Improving coke strength can effectively improve the airflow distribution and material flow in the blast furnace. Stronger coke can withstand greater loads and reduce its breakage in high temperature environments, thereby reducing the risk of blast furnace blockage, optimizing heat transfer, and improving the stability and efficiency of blast furnace operation. High-strength coke can reduce the generation of fine particles, reduce environmental pollution and waste generation, and help achieve more environmentally friendly steel production. In addition, the increase in coke strength can also help maintain the stability of the chemical composition of molten iron and improve product quality. Therefore, in order to improve blast furnace production efficiency and achieve sustainable development of the steel industry, coke strength must be further improved.

[0004] At present, the method of adding hard powdery substances, tar, plasticizers and other materials is mainly used to improve the strength and stability of coke. Hard powdery substances such as artificial quartz sand, alumina, sodium silicate, etc. can improve the density and bonding properties of coke, thereby improving the wear resistance and strength of coke. CN110804449A discloses a method for preparing coke by coking calcium ferrite and non-coking coal, which includes the following steps: firstly, calcium ferrite is pelletized, then non-coking coal is wrapped outside the calcium ferrite pellets to form large pellets, and finally the large pellets are heated to 900-1300℃ under air-tight conditions for coking to obtain coke. The invention uses calcium ferrite as a binder, and calcium ferrite and the ash in non-coking coal are combined in the coking process to form Fe2O3-CaO-SiO2-Al2O3 quaternary composite calcium ferrite (SFCA), which can not only effectively reduce the ash content of coke, but also improve the strength of coke and improve the quality of coke.

[0005] Tar has the function of increasing the binding force of coke. Adding tar directly in the coke oven or in the preparation of raw materials can improve the strength and anti-crushing ability of the obtained coke. However, in general, the amount of tar added should be controlled below 5%, otherwise it will reduce the quality of the coke. Plasticizers are generally high molecular polymers, such as polypropylene, polyamide, etc. In the process of coke preparation, the addition of plasticizers can improve the flexibility and plasticity of coke, thereby improving the strength and wear resistance of coke.

[0006] As can be seen from the above, adding certain specific materials, such as hard powdery substances, tar, plasticizers, etc., can effectively improve the cold and hot strength of coke, but the proportion of additional added materials in the above methods is high, or special processes are required for coking, resulting in high production costs. Therefore, it is necessary to study a new, convenient and low-cost method to improve the quality of coke. Summary of the invention

[0007] In view of the above technical problems, the present invention provides a coal blending method for improving the quality of coke using carbon fiber and high-strength carbon fiber coke, aiming to improve the quality of coke while expanding the coal resources for coking and reducing production costs.

[0008] The technical solution adopted by the present invention to solve the technical problem is:

[0009] In a first aspect, the present invention provides a coal blending method for improving the quality of coke by using carbon fiber: carbon fiber is added to the coal during coal blending.

[0010] In the above coal blending method, the amount of carbon fiber added is 0 to 0.2% of the mass of the coal and is not 0.

[0011] Furthermore, in the above coal blending method, for every 0.1% of carbon fiber added, the coke crushing strength increases by >3.0%, the wear resistance decreases by >0.5%, and the strength increases by >3.0% after the reaction.

[0012] In the above coal blending method, the carbon fiber has a carbon content of 90-96wt%, a rubber content of 0.8-1.2wt%, a modulus of 200-300GPa, a strength of 3000-7000MPa, and a density of 1.6-2.0g / cm 3 , elongation is 1.0~3.0%, and single fiber diameter is 5~10μm.

[0013] In a second aspect, the present invention provides a high-strength carbon fiber coke produced by coal blending and coking using the above-mentioned coal blending method.

[0014] The raw material composition of the above-mentioned high-strength carbon fiber coke is carbon fiber and basic coal sample in a mass ratio of 0.005 to 0.2:1.

[0015] The composition of the above-mentioned basic coal sample includes at least one of gas coal, fat coal, coking coal, 1 / 3 coking coal, and lean coal.

[0016] Furthermore, the composition of the above basic coal sample is 0-65 weight parts of gas coal, 0-20 weight parts of fat coal, 10-50 weight parts of coking coal, 5-30 weight parts of 1 / 3 coking coal, and 0-20 weight parts of lean coal.

[0017] Furthermore, the above-mentioned gas coal, fat coal, coking coal, 1 / 3 coking coal and lean coal comply with the national standard for coal classification in China (GB / T5751-2009).

[0018] The coking method of the high-strength carbon fiber coke comprises the following steps:

[0019] a. Crush and screen the coal separately, and then mix them to obtain a basic coal sample;

[0020] b. mixing the base coal sample and the carbon fiber to obtain a mixture;

[0021] c. Loading the mixture into the coke oven carbonization chamber at a preset bulk density and compacting to obtain briquettes;

[0022] d. The coal cakes in the carbonization chamber are heated and subjected to a constant temperature dry distillation process, and high-strength carbon fiber coke is obtained after the coke pushing, quenching and coke screening processes.

[0023] Furthermore, in the above step a, the particle size of the basic coal sample is 0.5 to 3 mm.

[0024] Furthermore, in the above step c, the preset bulk density is 0.8-1.2 t / m 3 .

[0025] Furthermore, in the above step d, the coal cake is heated to 850-900°C at a heating rate of 20°C / min, and then heated to 1050-1150°C at a heating rate of 10°C / min for constant temperature dry distillation for 8-24h.

[0026] The beneficial effect of the present invention is that the addition of carbon fiber in the coking coal mixing stage can significantly improve the crushing strength, wear resistance and post-reaction strength of coke, thereby stabilizing production and reducing ironmaking costs. The present invention has high economic value and good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a process flow chart for preparing high-strength carbon fiber coke. DETAILED DESCRIPTION

[0028] The technical solution of the present invention can be specifically implemented in the following manner.

[0029] A coal blending method for improving the quality of coke by using carbon fiber, that is, adding carbon fiber to the coal during coal blending.

[0030] When too much carbon fiber is added, the cost of coke production will increase significantly. Therefore, the present invention limits the amount of carbon fiber added in the above-mentioned coal blending method to 0-0.2% of the mass of the coal and not 0; when the amount of carbon fiber added is 0-0.2% of the mass of the coal and not 0, for every 0.1% of carbon fiber added to the mass of the coal, the increase ratio of the coke's crushing strength is >3.0%, the decrease ratio of wear resistance is >0.5%, and the increase ratio of strength after reaction is >3.0%.

[0031] The mechanism by which carbon fiber increases coke strength involves multiple aspects, which can be summarized as follows:

[0032] (1) Carbon fiber itself is a material with extremely high tensile strength and elastic modulus, which means that when carbon fiber is embedded in the coke matrix, the strength and stiffness of the overall composite material will be significantly improved;

[0033] (2) Carbon fiber and coking coal will form a tight and good interface bond during the coking process. The strong interface bond helps to effectively transfer stress between the carbon fiber and the coke matrix, reducing the possibility of stress concentration and interface failure. When the fibers are distributed in an appropriate arrangement, they can also form a "fishbone" or "net" structure, which effectively disperses the stress and further improves the coke strength;

[0034] (3) Carbon fiber exists in the coke matrix as an elastic reinforcing phase, which can absorb the crack propagation energy through pinning effect and prevent the crack from enlarging, thereby improving the coke's anti-pulverization and anti-cracking capabilities.

[0035] The technical solution and effects of the present invention are further illustrated below through practical examples.

[0036] Example

[0037] 1. Prepare the ingredients

[0038] (1) The coal materials used in this embodiment are gas coal, fat coal, coking coal, 1 / 3 coking coal and lean coal. The industrial analysis of different coal materials is shown in Table 1. The five kinds of coal materials are pre-screened respectively, and the screened materials are crushed in a crusher. The crushed coal materials are screened again and mixed to obtain a basic coal sample, wherein the coal material particle size is between 0.5 and 3 mm. The components of the basic coal sample are as follows by mass percentage: gas coal 8%, fat coal 17%, coking coal 42%, 1 / 3 coking coal 18%, and lean coal 15%.

[0039] Table 1 Industrial analysis of coal samples (%)

[0040] Coal Sample <![CDATA[M ad ]]> <![CDATA[A ad ]]> <![CDATA[V ad ]]> <![CDATA[FC ad ]]> gas coal 0.31 7.66 39.08 52.95 Fat coal 0.74 9.61 31.72 57.93 Coking coal 0.30 7.52 22.25 69.93 1 / 3 coking coal 0.34 7.12 34.40 58.14 lean coal 0.70 13.92 18.34 67.04

[0041] (2) The basic properties of the carbon fiber used in this embodiment are shown in Table 2.

[0042] Table 2 Basic properties of carbon fiber

[0043] Carbon content Glue content Modulus strength density Elongation Monofilament diameter 95wt% 0.8wt% 240GPa 4900MPa <![CDATA[1.80g / cm 3 ]]> 2.1％ 6.9μm

[0044] 2. Preparation of high-strength carbon fiber coke

[0045] The preparation process of the high-strength carbon fiber coke of the present invention is as follows: Figure 1 Specifically, the carbon fiber and the basic coal sample are mixed in the proportions in Table 3 to obtain a mixture, and the mixture is loaded into the carbonization chamber of the laboratory coke oven at a preset bulk density to obtain briquettes; the compacted bulk density of the mixture is 0.85 t / m 3 The briquette was heated to 850°C at a heating rate of 20°C / min, and then heated to 1050°C at a heating rate of 10°C / min. After keeping the temperature constant for 8 hours, the heating was stopped and cooled at room temperature to obtain high-strength carbon fiber coke.

[0046] Table 3 Mass ratio of carbon fiber and basic coal sample

[0047] Comparative Example 1 Example 1 Example 2 Example 3 Example 4 0:1 0.005:1 0.010:1 0.015:1 0.020:1

[0048] 3. The cold and hot properties of the high-strength carbon fiber coke are shown in Table 4.

[0049] Table 4 Cold and hot properties of the obtained coke

[0050] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 <![CDATA[Crushing strength M 40 (%)]]> 86.9 90.7 92.6 93.3 82.2 <![CDATA[Wear resistance strength M 10 (%)]]> 7.3 6.9 6.5 6.2 7.8 Reactivity Index CRI (%) 27.2 26.3 25.1 24.0 28.0 Post-reaction strength CSR (%) 62.4 63.9 66.1 67.3 59.0

[0051] It can be seen that with the increase of the proportion of carbon fiber added, the crushing strength, wear resistance and post-reaction strength of coke are continuously improved, which shows that the addition of carbon fiber can effectively improve the performance of coke.

Claims

1. A coal blending method for improving coke quality by using carbon fiber, characterized in that: When blending coal, carbon fiber is added to the coal; The amount of the carbon fiber added is 0-0.2% of the mass of the coal material and is not 0.

2. The method for blending coal by using carbon fiber to improve the quality of coke according to claim 1, characterized in that: The carbon fiber has a carbon content of 90-96wt%, a rubber content of 0.8-1.2wt%, a modulus of 200-300GPa, a strength of 3000-7000MPa, and a density of 1.6-2.0g / cm 3 , elongation is 1.0~3.0%, and single fiber diameter is 5~10μm.

3. The method for blending coal by using carbon fiber to improve the quality of coke according to claim 1, characterized in that: For every 0.1% of carbon fiber added, the coke crushing strength M 40 Growth ratio>3.0%, wear resistance M 10 The reduction ratio is >0.5%, and the post-reaction strength CSR increase ratio is >3.0%.

4. High-strength carbon fiber coke, characterized by: The coal is blended by the coal blending method according to any one of claims 1 to 3 and then coked.

5. The high-strength carbon fiber coke according to claim 4, characterized in that: Its raw material composition is carbon fiber and basic coal sample with a mass ratio of 0.005 to 0.2:1; The composition of the basic coal sample includes at least one of gas coal, fat coal, coking coal, 1 / 3 coking coal, and lean coal.

6. The high-strength carbon fiber coke according to claim 5, characterized in that: The composition of the basic coal sample is 0-65 parts by weight of gas coal, 0-20 parts by weight of fat coal, 10-50 parts by weight of coking coal, 5-30 parts by weight of 1 / 3 coking coal, and 0-20 parts by weight of lean coal.

7. The high-strength carbon fiber coke according to claim 4, characterized in that: The coking process comprises the following steps: a. Crush and screen the coal separately, and then mix them to obtain a basic coal sample; b. mixing the base coal sample and the carbon fiber to obtain a mixture; c. The mixture is loaded into the coke oven carbonization chamber and compacted to obtain briquettes at a preset bulk density; d. The coal cakes in the carbonization chamber are heated and subjected to a constant temperature dry distillation process, and high-strength carbon fiber coke is obtained after the coke pushing, quenching and coke screening processes.

8. The high-strength carbon fiber coke according to claim 7, characterized in that: In step a, the particle size of the basic coal sample is 0.5 to 3 mm.

9. The high-strength carbon fiber coke according to claim 7, characterized in that: In step c, the preset bulk density is 0.8-1.2 t / m 3 .

10. The high-strength carbon fiber coke according to claim 7, characterized in that: In step d, the coal cake is heated to 850-900° C. at a heating rate of 20° C. / min, and then heated to 1050-1150° C. at a heating rate of 10° C. / min for constant temperature dry distillation for 8-24 hours.

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