A method for producing iron coke using a chamber coking process

Abstract

A method for producing ferrocoke using a chamber coking process is disclosed. This method employs a tamping process to produce iron-containing coal cakes, and fills the space between the iron-containing coal cakes and the carbonization chamber walls with coking coal that does not contain iron ore powder. No additional heat transfer medium is required, ensuring a high iron ore powder ratio and ferrocoke strength under chamber coking conditions, while simultaneously preventing corrosion and damage to the traditional coke oven carbonization chamber walls. Using this method, the iron ore powder ratio can reach 10-20%, and compared to directly coking with iron-containing coal cakes without filling with coking coal, coke production can be increased by 5-15%. This method can directly utilize existing chamber coking equipment to produce ferrocoke, resulting in low investment and operating costs.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of production of carbon-containing composite burden for blast furnace, and particularly relates to a method for producing iron coke by using chamber coking process. BACKGROUND

[0002] Carbon-containing composite burden is one of the technical directions for improving the efficiency of blast furnace smelting and reducing carbon emissions. Iron coke is an important carbon-containing composite burden, which is a kind of iron-containing carbon-containing burden obtained by mixing iron oxides (iron ore powder) into coking blending coal at a certain ratio and then sintering by coking or non-coking process. The current steel industry is the key industry to achieve CO2 emission reduction, and the CO2 emission of blast furnace ironmaking system accounts for more than 80% of the entire process, which is the main link of energy saving and emission reduction in the entire steel industry. Among various low-carbon ironmaking technical directions, the use of iron coke in blast furnace has small impact on the blast furnace system and high technical and economic efficiency, and is the most easily implemented measure at present.

[0003] There are mainly two production process methods for iron coke at present, traditional chamber coking process and non-coking oven process. The traditional chamber coking process, mainly represented by the iron coke production process adopted by Nippon Steel, mixes coal powder and iron ore powder (1-10%) in advance, then places the mixture in a galvanized steel box, and then places the steel box in a coke oven, carbonizes at 1250℃ for 18.5h, and finally uses dry quenching method to obtain iron coke. Because the addition of iron ore powder will reduce the overall cohesiveness of the blending coal and affect the strength of the coke structure, the proportion of iron ore powder cannot exceed 10%. In addition, galvanized steel boxes are used instead of directly pouring the raw materials into the carbonization chamber because FeO in the iron coke reacts with SiO2 in the furnace wall of the carbonization chamber to form fayalite at 1200℃, thereby corroding and damaging the furnace wall of the carbonization chamber. The non-coking oven process, mainly represented by the iron coke production process adopted by JFE Steel Corporation, mixes coking coal with particle size less than 3mm and iron ore powder (less than 74μm accounts for more than 81%), then heats the mixture to 110-130℃, and hot-presses the raw materials into shape by a roll forming machine, and finally carbonizes the hot-pressed iron coke in a shaft furnace for 6h to obtain iron coke, with carbonization temperature being 1100℃. The advantage of this process is that the proportion of iron ore powder can be increased (20-30%) by hot-pressing, and the strength of the iron coke can be guaranteed by carbonization and shaping in a shaft furnace, but this process needs to be matched with a roll forming machine and an industrial shaft furnace as well as corresponding facilities, with high investment and production cost, and is not suitable for promotion in traditional coking process enterprises. SUMMARY

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of the present application is to provide a method for producing iron coke by using chamber coking process, which can guarantee a high proportion of iron ore powder and a certain strength of iron coke, and at the same time can guarantee that the carbonization chamber furnace wall will not be corroded and damaged without the use of heat transfer medium such as galvanized steel box.

[0005] In order to achieve the above-mentioned purpose, the technical scheme of the present application is:

[0006] A method for producing iron coke by chamber coking process, comprising the following steps:

[0007] (1) crushing iron ore powder to ensure that more than 80% of the particles are below 200 mesh, and the total iron content of the iron ore powder is 45-60%;

[0008] (2) preparing coking coal, the indicators are as follows: dry ash-free volatile matter V daf is 22-28%, ash A d is 6-9%, Gieseler fluidity logMF is 2.0-2.6, and total dilatation TD is 30-100; the fineness of the coking coal is required to be greater than 85%, i.e. the proportion of particles with a size of less than 3 mm;

[0009] (3) mixing 10-20% of the iron ore powder with 80-90% of the coking coal prepared in step (2) in a mass ratio, and adding water to adjust the moisture content of the mixed raw materials to 9-11%, then mixing uniformly and loading into a tamping coal loading and coke pushing car for tamping to form a coal cake, the bulk density is controlled at 0.95-1.15 t / m 3 , the size of the coal cake is controlled according to the size of the carbonization chamber of the coke oven, the width of the coal cake is 30-50 mm narrower than the width of the carbonization chamber, the height of the coal cake is 100-300 mm lower than the effective height of the carbonization chamber, and the length of the coal cake is the effective length of the carbonization chamber, the coal cake is pushed into the carbonization chamber through the machine side of the coke oven using the tamping coal loading and coke pushing car, ensuring that the center line of the coal cake enters along the center line of the carbonization chamber, and the machine side oven door is closed after entering;

[0010] (4) pouring the bulk coking coal prepared in step (2) into the carbonization chamber through the coke oven top coal charging hole using the coal charging car, the mass is 10-15% of the mass of the coking coal in the coal cake, and the bulk coking coal enters through the coal charging hole and partially fills the gap between the coal cake and the furnace wall, and partially accumulates on the upper part of the iron-containing coal cake, and the tamping coal loading and coke pushing car is used to push the coking coal accumulated on the upper part of the iron-containing coal cake to both sides to fall and fill into the gap between the coal cake and the furnace wall through the small window on the upper part of the machine side oven door, and the above steps complete the distribution process of the iron coke production raw materials in the carbonization chamber;

[0011] (5) the coking temperature is 1200-1300℃, the coking time is 18-22h, after the coke matures, the iron coke is pushed out from the coke side by the tamping coal loading and coke pushing car and falls onto the coke blocking car, and is transported to the dry quenching coke oven for quenching, and finally the iron coke is obtained.

[0012] The coking coal mentioned is coking coal; or 1 / 3 coking coal; or a mixture of gas coal, 1 / 3 coking coal, fat coal, coking coal and lean coal in any proportion.

[0013] Advantages of this invention:

[0014] 1. Use the tamping process to produce iron-containing coal cakes to ensure the proportion of iron ore powder and the strength of iron coke under the chamber coking process.

[0015] 2. Fill the space between the coal briquettes and the carbonization chamber walls with coking coal free of iron ore powder to prevent corrosion and damage to the traditional coke oven carbonization chamber walls. The way iron ore and coke raw materials are distributed in the traditional coke oven carbonization chamber ensures the proportion of iron ore powder and the strength of the coke. This is because the iron-containing coal briquettes produced through tamping increase the overall bulk density and reduce the gaps between coal particles and iron ore powder particles. This allows the coking coal to fully utilize its binding properties, effectively binding the iron ore powder particles during carbonization and improving overall strength. Therefore, using this method, the iron ore powder proportion can reach 10-20%, which is 0-10% higher than the Nippon Steel process. Filling the space between the iron-containing coal briquettes and the carbonization chamber walls with coking coal free of iron ore powder prevents corrosion and damage to the carbonization chamber walls and improves heat transfer efficiency. Furthermore, compared to directly coking with iron-containing coal briquettes without filling with coking coal, this method can increase coke production by 5-15%.

[0016] 3. The required production equipment includes: chamber coke oven, coal charging car, tamping coal charging and pushing car, and coke blocking car, which are supporting facilities used in conventional coking processes; the investment and operating costs are low, and the iron coke has a certain strength, while not causing corrosion or damage to the furnace wall bricks of the carbonization chamber. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the distribution of raw materials in the carbonization chamber for iron coke production. Detailed Implementation

[0018] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0019] Example 1

[0020] This embodiment includes the following steps:

[0021] Iron coke is produced by using a 6m chamber coke oven, the size of the carbonization chamber is: effective height 5900mm, effective length 15000mm, width 450mm. Iron ore powder is crushed, the particle size under 200 mesh accounts for 82%, the total iron content TFe is 45%; the coking coal can be coking coal or 1 / 3 coking coal, but in order to save valuable coking coal resources and further improve the quality of iron coke products, it is most suitable to use any proportion of mixed coal composed of gas coal, 1 / 3 coking coal, fat coal, coking coal and lean coal; the coking coal of this embodiment is a single 1 / 3 coking coal, the volatile matter V daf (dry ash-free basis) is 28%, the ash content A d is 6%, the Gieseler fluidity logMF is 2.6, the TD (total expansion) is 100, and the fineness is 86%; the dry basis mass ratio of 10% iron ore powder and the mass ratio of 90% coking coal are mixed uniformly, and water is added to adjust the moisture content, so that the moisture content of the mixed raw materials is 10%, and after mixing, it is loaded into the tamping coal charging and coke pushing car for tamping, and the bulk density is controlled at 0.95t / m 3 The size of the coal cake is width 420mm, height 5600mm, length 15000mm, and after tamping to form the iron-containing coal cake, the coal cake is pushed into the carbonization chamber through the coke oven machine side by the tamping coal charging and coke pushing car, ensuring that the center line of the coal cake enters along the center line of the carbonization chamber, and after entering, the machine side oven door is closed.

[0022] Referring to Figure 1 , 1 / 3 coking coal 3 is poured into the carbonization chamber 1 through the coke oven top charging hole by the coal charging car, and the mass is 10% of the mass of the coking coal in the iron-containing coal cake, and the bulk coking coal enters through the charging hole, part of which fills the gap between the coal cake and the oven wall, and part of which accumulates on the upper part of the iron-containing coal cake. For the coking coal accumulated on the upper part of the coal cake, the flat coal rod on the tamping coal charging and coke pushing car is inserted into the carbonization chamber through the small window on the upper part of the machine side oven door, and is moved from the machine side to the coke side, pushing the coking coal accumulated on the upper part of the iron-containing coal cake to disperse and fall into the gap between the coal cake 4 and the oven wall 2. The above steps complete the distribution process of the iron coke production raw materials in the carbonization chamber.

[0023] The coking temperature is 1200℃, the coking time is 22h, and after the coke matures, the iron coke is pushed out from the coke side by the tamping coal charging and coke pushing car and falls into the coke blocking car, which is transported to the dry quenching coke oven for quenching, and finally the iron coke is obtained.

[0024] Example 2

[0025] This embodiment includes the following steps:

[0026] Iron coke is produced using a 6m chamber coke oven. The carbonization chamber dimensions are: effective height 5900mm, effective length 15000mm, and width 450mm. Iron ore powder is crushed, with 85% of particles smaller than 200 mesh and a total iron content (TFe) of 60%. The coking coal is a mixture of gas coal, 1 / 3 coking coal, fat coal, coking coal, and lean coal, with a volatile matter content (V). daf (Dry, ash-free basis) 22%, Ash content A d The iron ore powder has a dry weight ratio of 9%, a Gibbs freeness (logMF) of 2.0, a total expansion (TD) of 30, and a fineness of 88%. 20% iron ore powder (dry basis) is mixed evenly with 80% coking coal (dry basis), and water is added to adjust the moisture content to 10%. The mixture is then loaded into a compacting charging car for compaction, with the bulk density controlled at 1.15 t / m³. 3 The coal cake has a width of 400mm, a height of 5700mm, and a length of 15000mm. After being compacted to form an iron-containing coal cake, the coal cake is pushed into the carbonization chamber through the coke oven machine side using a compacted coal charging and coke pushing car, ensuring that the center line of the coal cake enters along the center line of the carbonization chamber. After entering, the machine side furnace door is closed.

[0027] Mixed coal, comprising 15% of the coking coal mass in the iron-containing coal cake, is poured into the carbonization chamber through the coal charging hole on the top of the coke oven using a coal charging car. After entering through the charging hole, some of the bulk coking coal fills the gap between the coal cake and the furnace wall, while some accumulates on top of the iron-containing coal cake. For the coking coal accumulated on top of the coal cake, a leveling rod on the tamping charging and pushing car extends through a small window on the upper part of the furnace door on the machine side into the carbonization chamber. Moving from the machine side to the coke side, it pushes the coking coal accumulated on top of the iron-containing coal cake to both sides, filling the gap between the coal cake and the furnace wall. These steps complete the feeding process of the raw materials for iron-coke production within the carbonization chamber.

[0028] The coking temperature is 1300℃ and the coking time is 18h. After the coke matures, the iron coke is pushed out from the coke side by a tamping and charging coke pusher and falls into a coke quenching car, which is then transported to a dry quenching oven for quenching, and finally iron coke is obtained.

[0029] The two embodiments above, compared to Nippon Steel's chamber coking method, can increase the amount of iron ore powder added, from 1-10% to 10-20%, with the embodiments being 10% and 20% respectively, without affecting the coke strength or corroding or damaging the carbonization chamber walls. Compared to JFE's hot-pressing coking process, this method does not require the addition of a roll forming machine and an industrial vertical furnace, reducing investment, and can be implemented using a chamber coking oven and related supporting equipment.

[0030] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for producing iron coke using a chamber coking process, characterized by, It comprises the following steps: (1) crushing iron ore powder to ensure that more than 80% of the particles are below 200 mesh, and the total iron content of the iron ore powder is 45-60%; (2) Prepare coking coal with the following requirements: volatile matter V on a dry, ash-free basis. daf Ash content A is 22-28%. d The fineness requirement for coking coal is 6-9%, the Gibbs freeness (logMF) is 2.0-2.6, and the total expansion (TD) is 30-100; the fineness requirement for coking coal is greater than 85%, that is, the proportion of particles <3mm. (3) Mix the iron ore powder with the coking coal prepared in step (2) in a mass ratio of 10-20% of the iron ore powder and 80-90% of the coking coal, and add water to adjust the moisture content of the mixture to 9-11%, and then mix well and load into the tamping coal loading and coke pushing car to form a coal cake by tamping, and the bulk density is controlled to be 0.95-1.15 t / m 3 The size of the coal cake is controlled according to the size of the carbonization chamber of the coke oven, the width of the coal cake is 30-50 mm narrower than the width of the carbonization chamber, the height of the coal cake is 100-300 mm lower than the effective height of the carbonization chamber, and the length of the coal cake is the effective length of the carbonization chamber. The coal cake is pushed into the carbonization chamber through the machine side of the coke oven by the tamping coal loading and coke pushing car, so as to ensure that the center line of the coal cake enters along the center line of the carbonization chamber, and the machine side oven door is closed after entering. (4) the bulk coking coal prepared in step (2) is poured into the carbonization chamber through the coke oven top charging hole by the charging car, and the mass is 10-15% of the mass of the coking coal in the coal cake. The bulk coking coal enters through the charging hole and partially fills the gap between the coal cake and the oven wall, and partially accumulates on the upper part of the iron-containing coal cake. For the coking coal accumulated on the upper part of the coal cake, the flat coal rod on the stamp charging and pushing car is used to extend into the carbonization chamber through the small window on the upper part of the machine side oven door, and is moved from the machine side to the coke side, pushing the coking coal accumulated on the upper part of the iron-containing coal cake to disperse and fall into the gap between the coal cake and the oven wall. Through the above steps, the distribution process of the iron coke production raw materials in the carbonization chamber is completed; (5) the coking temperature is 1200-1300℃, the coking time is 18-22h, and after the coke matures, the iron coke is pushed out from the coke side by the stamp charging and pushing car and falls onto the coke blocking car, which is transported to the dry quenching coke oven for quenching, and finally the iron coke is obtained.

2. A process for producing iron coke using a chamber coking process as claimed in claim 1, wherein, The coking coal is coking coal; or 1 / 3 coking coal; or a mixed coal composed of gas coal, 1 / 3 coking coal, fat coal, coking coal and lean coal in any proportion.

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