Coke prepared with blue coke and coking method

Abstract

The present invention discloses a coke prepared with blue coke and a coking method, which mainly solves the technical problem that the coke prepared with blue coke has a low post-reaction strength (CSR) and cannot be used in large proportions for coking with coal to produce high-quality metallurgical coke with stable quality. The technical solution is that the coke prepared with blue coke is prepared by coking with the following coal blending percentages by mass: 1 / 3 coking coal 20% to 24%, gas coal 12% to 16%, fat coal 16% to 20%, coking coal 30% to 34%, lean coal 2% to 6%, blue coke 6% to 10%, coal tar 6% to 10%, and the sum of the mass percentages of the blended coal components is 100%; the dry ash-free volatile matter V of the blue coke is 10% to 10%. daf The carbon content is 14% to 18%, the ash content is 9.5% to 10.5%, the particle size of the blue coke is less than 1mm, and the particle size of the coal tar is less than 1mm. The coke of the present invention is high-strength metallurgical coke, and the strength CSR of the coke after reaction is 66% to 68%.

Description

Technical Field

[0001] The present invention relates to coke and a coking method, in particular to coke prepared with blue coke and a coking method, belonging to the technical field of coal chemical industry. Background Art

[0002] With the rapid development of steel companies and the continued expansion of coking capacity, the shortage of high-quality coking coal and the increasingly stringent requirements for coke quality have become increasingly prominent, making the search for new and viable coking resources particularly important. Semi-coke (also known as semi-coke) is a light black, porous mass formed by drying, degassing, softening, melting, flowing, expanding, and solidifying weakly coking coal at temperatures below 750°C.

[0003] Lignite is a product of medium-temperature dry distillation of low-rank coal. As a clean energy source, it features high fixed carbon, low ash, sulfur, and phosphorus content. However, because it lacks the adhesive properties of coking coal, it is generally used only as a fuel. While lignite's high carbon content and low ash and sulfur content could lower the ash and sulfur content of coke if used as a coking blend, the primary limitation is its lack of adhesiveness, making it difficult to blend with coking coal to produce high-strength coke. This is the primary barrier to its use as a coking blend.

[0004] The paper "Study on the Use of Semi-coke in Coking Coal Blending" (Cheng Jun, Sun Baodong, Zhang Xinmin; Metallurgy and Materials, 2020(40), 4, pp. 9-12) introduces the analysis of the effect of adding semi-coke to coking coal on the quality and production of coke based on the 40kg small coke oven test and the 6m coke oven production test. The study shows that the use of semi-coke in coking coal causes a decrease in the cold strength and hot strength of coke, especially the cold strength. By adjusting the coal blending structure and increasing the proportion of fat coal, about 2% semi-coke is added while maintaining the coke quality without significant impact. Since the price of fat coal is much higher than that of semi-coke and the semi-coke blending ratio is low, the cost reduction is limited.

[0005] Chinese patent application publication number CN111826183A discloses a coke, a method for preparing the same, and an apparatus for preparing the coke. The coke is produced by coking a mixture of the following components by weight: 1 / 3 coking coal (32-40%), fat coal (22-28%), coking coal (32-38%), and lignite (2-5%). Compared to existing technologies, lignite is added to the coke blend as a thinning agent, replacing clean coking coal. By adjusting the coal blending structure and optimizing the coal preparation and coking process for lignite coking, the adaptability of lignite is improved, ensuring the quality of the coke after adding lignite. This also conserves high-quality coking coal resources, reduces production costs, and expands the application range of lignite. This patent adjusts the coal blending structure by increasing the amount of highly caking coal, such as fat coal, to counteract the deterioration of the caking properties of the blended coal. Highly caking coking coal is the most scarce resource in coking, resulting in a waste of high-quality coking coal resources.

[0006] The paper "Lan Coke Modification and Coal Blending Optimization" (Li Shuo, Zhu Zizong, Xu Jun, Song Nan; Steel, 2012 (47), 8, pp. 17-21) introduced that in order to expand the application range of semi-coke, semi-coke and coal blending and optimization tests were carried out in a 40kg coke oven by using pulverized coal modifier. When the semi-coke ratio was 5%, the bonding index, maximum thickness of the gel layer, Oya expansion, plastic range and maximum fluidity of the blended coal all decreased, and the coke quality deteriorated. With the increase of pulverized coal modifier, the coke quality was improved. When the mass fraction of the additive reached 0.1%, the improvement of the coke quality was the largest. 40 、M 10 The coking index of CSR is close to that of the original coal and can meet the production requirements. The problem with this solution is that the cost of the pulverized coal modifier is high, which is 9-10 times the cost of coking coal. Although it can save coking coal resources, its coking cost increases significantly.

[0007] In summary, the existing lignite-coal coking has the technical problem of reduced coking properties of the blended coal. Adjusting the existing coal blending structure to achieve the coking properties of the blended coal will inevitably consume a large amount of highly coking coal, which fails to achieve the purpose of saving high-quality coking coal. The quality of coke can be improved by adding coal powder modifiers, but the price of special coal powder modifiers is much higher than that of coking coal, and their practical application is limited. In the existing lignite-coal coking, the mass proportion of lignite in the blended coal is ≤5%, and the usage of lignite is low. Summary of the Invention

[0008] The purpose of the present invention is to provide a coke prepared with blue coke and a coking method, which mainly solves the technical problem that the coke prepared with blue coke has low strength after reaction (CSR) and cannot be used in large proportion for coal coking to produce high-quality metallurgical coke with stable quality; the coke produced by the present invention is high-quality metallurgical coke, which meets the requirements of 4000m 3 And above the needs of blast furnace smelting.

[0009] The method of the present invention adopts semi-coke blending with coal for coking. By rationally blending coal and adding coal tar, the technical difficulty of semi-coke having no coking property is overcome, and the quality of the blended coal is ensured to meet the index of high-quality coking coal. High-quality metallurgical coke with stable quality can be produced on a top-loading coke oven, and the problems of large consumption of strongly caking coal and deterioration of coke quality are solved, thereby reducing the coal blending cost and saving high-quality coking coal resources.

[0010] The technical solution adopted by the present invention is that a coke with blue coke is prepared by mixing and coking the following coals in the following mass percentages: 1 / 3 coking coal, 20% to 24%, gas coal, 12% to 16%, fat coal, 16% to 20%, coking coal, 30% to 34%, lean coal, 2% to 6%, blue coke, 6% to 10%, and coal tar, and the sum of the mass percentages of the various components of the mixed coal is 100%.

[0011] The dry ash-free volatile matter V of the blue carbon of the present inventiondaf The dry ash-free volatile matter V of coal tar is 14% to 18%, and the ash content is 9.5% to 10.5%. daf The crude oil content is 40-50%, and the ash content is 0.3-0.5%.

[0012] The coal tar pitch and other single coking coals used in the present invention are of a quality that conforms to the classification indexes in the corresponding national standards.

[0013] Before coal blending, the semi-coke and coal tar are pre-crushed respectively to control the particle size of semi-coke to be less than 1mm and the particle size of coal tar to be less than 1mm.

[0014] The dry ash-free volatile matter V of the blended coal of the present invention daf The viscosity is 26% to 28%, the adhesion index G is 78 to 80, the fluidity LGMF is 2.0 to 3.0, and the maximum thickness Y of the colloid layer is 14 to 16 mm.

[0015] After coal blending, the blended coal needs to be crushed, and the proportion of blended coal with particle size less than 3mm accounts for 75.0% to 78.0% of its total mass.

[0016] The coke of the present invention is a high-strength metallurgical coke with a coke reactivity CRI of 22-24%, a coke strength after reaction CSR of 66%-68%, and a coke drum strength of 1. 87-89%, coke crushing strength M 40 The coke wear resistance strength M is 87-89%. 10 It is 5.8~6.2%.

[0017] A coking method using blue coke comprises the following steps:

[0018] 1) Coal blending, blending according to the following mass percentages: 1 / 3 coking coal 20% to 24%, gas coal 12% to 16%, fat coal 16% to 20%, coking coal 30% to 34%, lean coal 2% to 6%, semi-coke 6% to 10%, coal tar 6% to 10%, and the sum of the mass percentages of the blended coal components is 100%; the dry ash-free volatile matter V of the semi-coke daf The dry ash-free volatile matter V of coal tar is 14% to 18%, and the ash content is 9.5% to 10.5%. daf The content of fat is 40-50%, and the ash content is 0.3-0.5%;

[0019] 2) crushing the blended coal;

[0020] 3) Coal coking: the crushed coal is fed into a top-loading coke oven for coking at a coking temperature of 1000±50°C and a coking time of 22±2 hours;

[0021] 4) After the coke is removed, dry quench the coke and cool it down.

[0022] Afterwards, the coke quality test is carried out to determine the coke ash content, coke sulfur content, coke reactivity and post-reaction strength and other indicators.

[0023] Furthermore, before coal blending, the semi-coke and coal tar pitch are pre-crushed respectively to control the particle size of the semi-coke to be less than 1 mm and the particle size of the coal tar pitch to be less than 1 mm.

[0024] Furthermore, the dry ash-free volatile matter V of the blended coal daf The viscosity is 26% to 28%, the adhesion index G is 78 to 80, the fluidity LGMF is 2.0 to 3.0, and the maximum thickness Y of the colloid layer is 14 to 16 mm.

[0025] Furthermore, after the blended coal is crushed, the proportion of the blended coal with a particle size of less than 3 mm in the total mass is 75.0% to 78.0%, so as to ensure the acquisition of high-quality coke.

[0026] Furthermore, the coke oven has a coke oven carbonization chamber with a height of 6.8 to 7.2 meters.

[0027] Furthermore, coke cooling utilizes dry quenching (CDQ), using nitrogen to cool the red-hot coke. This not only reduces the coke's moisture content but also minimizes changes during rapid cooling, preventing a decrease in coke strength. The nitrogen, after heat exchange with the coke, can be recycled for thermal power generation, avoiding energy waste.

[0028] The coke produced by the method of the present invention is a high-strength metallurgical coke with a coke reactivity CRI of 22-24%, a coke strength after reaction CSR of 66%-68%, and a coke drum strength of 1. 87-89%, coke crushing strength M 40 The coke wear resistance strength M is 87-89%. 10 It is 5.8~6.2%.

[0029] The applicant's research found that lignite has no adhesive properties and can only play a skeleton role in coke, while coal tar, as a product of tar processing, has high fluidity when heated, and because its components come from coal, it can have good fusion with coal. Research on the microstructure of coke found that lignite, as an inert substance, can only form a strong skeleton effect when it is wrapped by active components. If it is not fused with other components, it can only play the role of inclusions, thereby destroying the strength of coke. In order to achieve full fusion of lignite particles with other components of coal, the particle size of lignite is first controlled, and full mixing is achieved through mixing and crushing; in addition, by adding coal tar and controlling the particle size, the active components have more opportunities to contact with inert components such as lignite, thereby forming a fusion body and improving the strength and quality of coke. From an economic point of view, the cost of coal tar is similar to that of coking coal. Since the cost of lignite is lower than that of coking coal, the overall cost of coal blending can be reduced.

[0030] Experiments show that after adopting the above technical solution of the present invention, the dry ash-free volatile matter V daf The coke has a strength of 26% to 28%, a cohesive index of 78 to 80, a fluidity of 2.0 to 3.0, and a maximum thickness of 14 to 16 mm. The coke has a strength of 66% to 68% after reaction, and a coke drum strength of 100%. It is 87-89%, which meets the needs of large blast furnace smelting.

[0031] Compared with the existing technology, the present invention has the following positive effects: 1. It expands the coking coal resources and reduces the coal blending cost. The lignite-coal blending ratio is expanded, and lignite is used to replace part of the coking coal, so that the resources are optimized. Since the price of lignite is lower than that of coking coal, the cost of the blending coal is reduced by the participation of lignite in the coal blending. 2. Maintaining a relatively high coke strength. In order to overcome the influence of lignite participating in the coal blending on the adhesion and fluidity of the blended coal, the present invention simultaneously adds coal tar to the coal blending to achieve a balance in the adhesion performance of the coal blending; based on the study of the coke microstructure, the particle size of the lignite is controlled to achieve the wrapping of the particles by the adhesive component, thereby maintaining the coke with a relatively high strength to meet the 4000m 3 3. The coke and coking method using blue coke provided by the present invention can be produced in a common top-charging coke oven and can obtain high-quality metallurgical coke without the need for forming. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to the examples, as shown in Tables 1 and 2.

[0033] The invention discloses a coke prepared by mixing and coking coal in the following mass percentages: 1 / 3 coking coal, 20% to 24%, gas coal, 12% to 16%, fat coal, 16% to 20%, coking coal, 30% to 34%, lean coal, 2% to 6%, semi-coke, 6% to 10%, and coal tar pitch, wherein the sum of the mass percentages of the various components of the prepared coal is 100%.

[0034] Dry ash-free volatile matter V of the semi-coke of the embodiment of the present invention daf The ash content is 14% to 18%, the ash content is 9.5% to 10.5%, and the particle size of the semi-coke is less than 1mm; the dry ash-free volatile matter V daf The content of the coking coal is 40-50%, the ash content is 0.3-0.5%, and the particle size of the coal tar is less than 1 mm. The performance parameters of the coking coal used in the embodiment are shown in Table 1.

[0035] In this embodiment of the present invention, coking was performed in a 7m top-loading coke oven with a designed coking time of 22 hours. Three blending ratios were used for verification. In Schemes 2 to 4, the proportions of semi-coke to the total weight of the blended coal were 6%, 8%, and 10%, respectively. The coke obtained from the 7m top-loading coke oven had a coke strength after reaction (CSR) of 66% to 68%. The specific blending ratios of the blended coal in this embodiment of the present invention are shown in Table 2.

[0036] The above-mentioned coke making method using blue charcoal comprises the following steps:

[0037] 1) Pre-crushing of semi-coke and coal tar. Pre-crush semi-coke and coal tar before coal blending to control the particle size of semi-coke to less than 1mm and the particle size of coal tar to less than 1mm.

[0038] 2) Coal blending: blending coal according to the following mass percentages: 1 / 3 coking coal 20% to 24%, gas coal 12% to 16%, fat coal 16% to 20%, coking coal 30% to 34%, lean coal 2% to 6%, semi-coke 6% to 10%, coal tar 6% to 10%, and the sum of the mass percentages of the blended coal components is 100%; the dry ash-free volatile matter V of the semi-coke is daf The dry ash-free volatile matter V of coal tar is 14% to 18%, and the ash content is 9.5% to 10.5%. daf The content of fat is 40-50%, and the ash content is 0.3-0.5%;

[0039] 3) crushing the blended coal, crushing the blended coal after blending, and after the blended coal is crushed, the proportion of the blended coal with a particle size of less than 3 mm in the total mass is 75.0% to 78.0%;

[0040] 4) Coal coking: the crushed coal is fed into a top-loading coke oven for coking at a coking temperature of 1000°C and a coking time of 22 hours;

[0041] 5) Cool the coke after it is unloaded. The coke is cooled by dry quenching.

[0042] Afterwards, the coke quality test was carried out to determine the coke reactivity and post-reaction strength, coke drum strength, coke crushing strength and abrasion resistance. The measurement results are shown in Table 2.

[0043] The dry ash-free volatile matter V of the blended coal in the embodiment of the present invention daf The viscosity of the coke is 26% to 28%, the adhesion index G is 78 to 80, the fluidity LGMF is 2.0 to 3.0, and the maximum thickness Y of the colloid layer is 14 to 16 mm. Compared with the prior art of coking with five types of coal, namely 1 / 3 coking coal, gas coal, fat coal, coking coal and lean coal, the coke has basically the same quality, and the coke strength after reaction (CSR) is 66% to 68%.

[0044] Table 1 Coking coal performance parameters of the present invention

[0045]

[0046] Table 2 Mass percentage of coking blend coal and coke performance parameters of the embodiment of the present invention

[0047]

[0048]

[0049] As shown in Table 2, after schemes 2 to 4 use semi-coke and coal tar to replace coking coal, fat coal and lean coal, the coke quality indicators obtained are basically the same as those of scheme 1 without semi-coke, meeting the 4000m 3 And above the needs of blast furnace smelting.

[0050] In addition to the above embodiments, the present invention may also have other implementations. Any technical solution formed by equivalent replacement or equivalent transformation falls within the scope of protection required by the present invention.

Claims

1. A coke prepared with blue charcoal, characterized in that: The invention is prepared by mixing and coking the following blended coals in the following mass percentages: 1 / 3 coking coal, 20% to 24%, gas coal, 12% to 16%, fat coal, 16% to 20%, coking coal, 30% to 34%, lean coal, 2% to 6%, semi-coke, 6% to 10%, and coal tar, wherein the sum of the mass percentages of the blended coal components is 100%; the semi-coke has a dry ash-free volatile matter V daf The ash content is 14% to 18%, the ash content is 9.5% to 10.5%, and the particle size of the semi-coke is less than 1mm; the dry ash-free volatile matter V daf The coke is high-strength metallurgical coke with a coke reactivity CRI of 22-24%, a coke post-reaction strength CSR of 66%-68%, and a coke drum strength of 100%. 87-89%, coke crushing strength M 40 The coke wear resistance strength M is 87-89%. 10 It is 5.8~6.2%.

2. The coke prepared with blue carbon as claimed in claim 1, wherein: The dry ash-free volatile matter V of the blended coal daf The viscosity is 26% to 28%, the adhesion index G is 78 to 80, the fluidity LGMF is 2.0 to 3.0, and the maximum thickness Y of the colloid layer is 14 to 16 mm.

3. The coke prepared with blue carbon as claimed in claim 1, wherein: After coal blending, the blended coal needs to be crushed, and the proportion of blended coal with particle size less than 3mm accounts for 75.0% to 78.0% of its total mass.

4. A coking method using blue coke, characterized in that: The following steps are involved: 1) Coal blending, blending according to the following mass percentages: 1 / 3 coking coal 20% to 24%, gas coal 12% to 16%, fat coal 16% to 20%, coking coal 30% to 34%, lean coal 2% to 6%, semi-coke 6% to 10%, coal tar 6% to 10%, and the sum of the mass percentages of the blended coal components is 100%; the dry ash-free volatile matter V of the semi-coke daf The ash content is 14% to 18%, the ash content is 9.5% to 10.5%, and the particle size of the semi-coke is less than 1mm; the dry ash-free volatile matter V daf The content of coal tar is 40-50%, the ash content is 0.3-0.5%, and the particle size of coal tar is less than 1mm; 2) crushing the blended coal; 3) Coal coking: the crushed coal is fed into a top-loading coke oven for coking at a coking temperature of 1000±50°C and a coking time of 22±2 hours; 4) Cool the coke after it is removed.

5. The coking method using blue coke as claimed in claim 4, wherein: After the blended coal is crushed, the proportion of blended coal with a particle size of less than 3 mm in the total mass is 75.0% to 78.0%; the dry ash-free volatile matter V daf The viscosity is 26% to 28%, the adhesion index G is 78 to 80, the fluidity LGMF is 2.0 to 3.0, and the maximum thickness Y of the colloid layer is 14 to 16 mm.

6. The coking method using blue coke as claimed in claim 4, wherein: The coke oven has a carbonization chamber height of 6.8 to 7.2 meters.

7. The coking method using blue coke as claimed in claim 4, wherein: The coke is cooled by dry quenching.

8. The coking method using blue coke as claimed in claim 4, wherein: The coke is high-strength metallurgical coke, with a coke reactivity CRI of 22-24%, a coke strength after reaction CSR of 66%-68%, and a coke drum strength of 1. 87-89%, coke crushing strength M 40 The coke wear resistance strength M is 87-89%. 10 It is 5.8~6.2%.

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