RU2790416C1 - Method for obtaining coke for blast furnace process - Google Patents

Abstract

FIELD: coke industry.

SUBSTANCE: invention relates to the field of coal processing and solid fuel chemical technology and can be used in coke chemical production, in particular, the production of blast furnace coke from partially or completely briquetted coal charge. A method for obtaining coke for blast furnace process, including coking of the charge at a temperature in the control verticals of 1200-1400°C for 14-20 hours. Moreover, the charge includes the following components, wt.%: coal briquettes 5.0–100.0; coal charge 0-95.0. At the same time, the size of coal briquettes is no more than 60 mm in any direction, and they are obtained from coal fines with a particle size of no more than 1.0 mm, a yield of volatile substances of 0-38%, an ash content of 0-20% and a binder in the amount of 0-5% of the mass of coal fines.

EFFECT: development of a method for preparing coal charge for coking with high processing properties, which makes it possible to maximize the technological potential of coal concentrates and, by improving the quality of coke, reduce its consumption in blast furnace process.

5 cl, 4 tbl, 2 ex

Description

The invention relates to the field of coal processing and chemical technology of solid fuels. It can be used in coke production, in particular, obtaining blast-furnace coke from partially or completely briquetted coal charge.

The main task of coke production is the development of optimal technological parameters for the preparation and coking of coal raw materials, which makes it possible to maximize the potential inherent in coal concentrates.

As is known from world and domestic practice, the content of small classes in the coal charge for coking negatively affects the sintering and coking properties, which in turn affects the quality characteristics of the resulting coke, and also violates the technological parameters of coking and worsens the quality characteristics of chemical coking products.

A known method of coking partially briquetted coal mixtures, including the separation of the flotation concentrate from the mixture, mixing the flotation concentrate with non-caking crushed coal in a ratio of 1:2 - 1:3 [Author's certificate SU No. 1171507, C10B57/08, 1985].

There is also a method of briquetting flotation concentrate with crushed heavy concentrate [Author's certificate SU No. 1399328, C10B57/08, 1988].

The disadvantage of these methods is the formation of a coal charge from ordinary coal and further enrichment, which has no feasibility study in real production conditions, as well as a fixed ratio of the grade composition of the coal charge.

A known method of preparing coal charge for coking, including dosing, sorting (classification), crushing, drying, mixing coal. According to the proposed method, before the final crushing, the coal charge is classified according to the granulometric composition, while separating the class with a fraction less than or equal to 6 mm, without subjecting it to grinding, and the remaining part of the charge is crushed and mixed with a pre-selected fraction less than or equal to 6 mm, dried to 4- 6% residual moisture, where a dusty class less than or equal to 0.5 mm is separated, followed by its briquetting and mixing of briquettes with dried charge for transfer to coke production [Patent RU No. 2550874, IPC C10B57/08, C10B53/08, C10L5/02 , 2015].

The implementation of this method is possible due to a complex change in the technological stage and the use of energy-intensive technological solutions. Therefore, a significant disadvantage of this method of preparing coal charge for coking is:

- introduction of an additional technological stage for preliminary crushing and drying of coal charge for coking;

- lack of a range of percentage participation of coal briquettes in the charge for coking;

- no indication of the size range of the resulting briquettes.

The closest in technical essence to the claimed technical solution is a method for producing coke for blast-furnace production, in which the coal charge for coke oven batteries is formed from 100% coal concentrates of brand Zh, while the coking process is carried out in 14-18 hours, depending on the design of the coke oven battery at a temperature in the control verticals of 1200-1400°C, while the resulting coking product has a characteristic in terms of strength after reaction with carbon dioxide of at least 48.0% [Patent RU No. 2745787, IPC C10B57/04, C10B57/16, 2021].

The disadvantage of this technical solution is that it does not involve the use of coal briquettes in the charge, which, in turn, does not allow the disposal of coal fines.

The technical result of the invention is the development of a method for preparing coal charge for coking with high technological properties, which makes it possible to maximize the technological potential of coal concentrates and, by improving the quality of coke, to reduce its consumption in blast-furnace production.

The specified technical result is achieved by the fact that in the method for producing coke for blast-furnace production, including coking of the charge at a temperature in the control verticals of 1200-1400 ° C for 14-20 hours, according to the invention, the charge has the following components, wt.%:

coal briquettes - 5.0 - 100.0;

coal charge - 0 - 95.0,

at the same time, the size of coal briquettes is not more than 60 mm in any of the directions, and they are obtained from coal fines with a particle size of not more than 1.0 mm, a volatile matter yield of 0-38%, an ash content of 0-20% and a binder in an amount of 0- 5% by weight of coal fines.

As a coal charge, coals of the following grades are used: gas, gas-fatty, fatty, coke-forming, coke-forming-weakly caking, weakly caking, lean, lean.

Coal briquettes before coking can be subjected to preliminary crushing.

The resulting coke has characteristics in terms of strength after reaction with carbon dioxide of at least 45.0%.

The essence of the proposed technical solution is as follows.

Small classes of coal concentrates with a particle size of no more than 1 mm are formed into coal briquettes with a size of no more than 60 mm in any of the directions, using no more than 5% of the binder. The resulting briquettes are dosed into the charge in accordance with the specified charge conditions as a separate component.

The ratio in the charge of coals of individual technological groups is determined both by resources and by the properties of coal concentrates. The percentage of participation of briquettes in the coal charge can vary from 5 to 100%. The step of 5% is due to the dosage accuracy.

Briquettes are fed into the coal charge in two ways, either by including them into the existing charge preparation system with subsequent crushing or by mixing non-crushed briquettes directly with the prepared coal charge.

Special coking modes compensate for the inclusion of a different percentage of coal briquettes in the coal charge. Thus, coking for 14-20 hours at a temperature in the control verticals of 1200-1400 °C ensures the production of coke with characteristics at the quality level required for the subsequent blast-furnace process.

Characteristics of the finished coke - the strength index after the reaction with carbon dioxide is not less than 45.0% indicates that the coking process took place in full and a product suitable for its use in the subsequent blast-furnace stage was obtained.

As an example of the implementation of the method, industrial experiments conducted in the coke shop of PJSC Severstal are presented.

As a raw material for the production of briquettes, coal concentrate produced by Vorkuta Coal with a size of "-1.0 mm" was used, from which two types of briquettes "Seeds" with a diameter of 4-6 mm were obtained by briquetting - obtained by extrusion. "Dumplings" 30x30x20 mm - obtained using the technology of roll briquetting.

Example 1

Coal briquettes "seeds" had a cylindrical shape with a diameter of 4-6 mm and a length of 5-30 mm. Qualitative characteristics of coal briquettes are shown in table 1.

Table 1

Sample name Technical analysis Ad,% Vdaf, % Briquettes C ("seeds") 8.6 33.4

As part of the experiment, coke was obtained from two types of charge:

- consisting of 100% coal briquettes "seeds";

- from a mixture of briquettes "seeds" with coal charge in the ratio of 50x50%.

Qualitative characteristics of coke and technological parameters of coking are presented in Table 2.

table 2

Name
samples Ad,% М40, % М10, % CRI, % CSR, % Period, h Temperature, ° С Coke from 100% briquettes "seeds" 11.8 68.8 7.2 36.8 49.1 16:48 1305 Coke from 50% briquettes "seeds" 11.1 67.0 6.7 32.6 52.3 16:48 1306

Example 2

Coal briquettes "dumplings" had the shape of an oblate ellipsoid 30x30x20 mm. Qualitative characteristics of coal briquettes are shown in table 3.

Table 3

Sample name Technical analysis Ad,% Vdaf, % Briquettes ("dumplings") 9.2 33.7

Within the framework of the experiment, coke was obtained from a charge consisting of a mixture of coal briquettes with coal charge in a ratio of 50x50%. Qualitative characteristics of coke and technological parameters of coking are presented in Table 4.

Table 4

Name
samples Ad,% М40, % М10, % CRI, % CSR, % Period, h Tem-ra, S Coke from 50% briquettes P 11.9 62.8 7.0 37.5 48.5 17:10 1294

As can be seen, the coke obtained during the experiments fully met the requirements for it at subsequent metallurgical stages.

The technical and economic advantages of the proposed method are that due to the improvement of the quality characteristics of coke, its consumption for the production of pig iron is reduced, the use of this technology maximizes the technological potential of coal concentrates, which in turn has a positive effect on reducing the cost of both pig iron and finished metal products, and also reduces the environmental load on the working environment.

Claims (8)

1. A method for obtaining coke for blast-furnace production, including coking the charge at a temperature in the control verticals of 1200-1400 ° C for 14-20 hours, characterized in that the charge includes the following components, wt.%: coal briquettes - 5.0–100.0; coal charge - 0 - 95.0, at the same time, the size of coal briquettes is not more than 60 mm in any direction, and they are obtained from coal fines with a particle size of not more than 1.0 mm, a volatile matter yield of 0-38%, an ash content of 0-20% and a binder in an amount of 0- 5% by weight of coal fines. 2. The method according to p. 1, characterized in that coal grades are used as coal charge: gas, gas-fatty, fatty, coke-forming, coke-forming-weakly caking, weakly caking, lean, lean. 3. The method according to p. 1, characterized in that the coal briquettes are subjected to preliminary crushing before coking. 4. The method according to p. 1, characterized in that the coal briquettes before coking are not subjected to preliminary crushing. 5. The method according to claim 1, characterized in that the resulting coke has characteristics in terms of strength after reaction with carbon dioxide of at least 45.0%.