A method for producing metallurgical coke using gas coal in large proportion

Abstract

The present invention relates to a method for producing metallurgical coke using a large proportion of gas coal, comprising: S1) preparing a single type of coking coal to be blended at a specific content, and S2) preparing the coal and tamping the coke. The method blends gas coals of varying qualities, replacing fat coal with gas-fat coal to maintain the required cohesiveness and fluidity of the blended coal, and replacing coking coal with one-third coking coal to ensure that the coking properties and strength of the blended coal meet the required standards. During the tamping process, the coking time is appropriately extended and the standard temperature is increased, achieving a large proportion of gas coal, an increase of 30% to 40% over the industry average, and fully utilizing gas coal resources. Furthermore, the use of coking coal and fat coal can be significantly reduced or even eliminated, reducing the consumption of scarce coal varieties.

Description

Technical Field

[0001] The invention belongs to the field of coking coal blending in the coking industry, and particularly relates to a method for producing metallurgical coke by blending gas coal in a large proportion. Background Art

[0002] While my country boasts abundant coal resources, high-quality coking coal, such as coking coal and fat coal, is scarce. However, resources such as slightly caking coal, gas coal, and one-third coking coal are relatively abundant. On the one hand, my country's massive coke production capacity is rapidly depleting coking coal resources. On the other hand, the expansion of blast furnaces is driving increasingly demanding coke quality. To improve coke strength, the proportion of coking coal and fat coal in the coal blending structure is continuously increasing. Excessive consumption of high-quality coking coal resources has significantly increased coke raw material costs, reduced profits, and diminished competitiveness. To reduce and mitigate coking coal and fat coal consumption, meet long-term development needs, lower coke raw material costs, and increase coke profits, it is necessary to expand the utilization of relatively abundant coal resources, such as slightly caking coal, gas coal, and one-third coking coal. Gas coal, in particular, is the most abundant coking coal resource in my country and is found in Shandong, Shanxi, Shaanxi, Jiangsu, and Inner Mongolia. Gas coal is also inexpensive and has low ash and sulfur content. Increasing its use can effectively mitigate the depletion of high-quality coking coal and reduce coke costs.

[0003] Patent CN 113088310 B introduces a ramming coal blending coking method, its product, and coking coal. The coking coal does not contain coking coal and fat coal. The types and weight percentages of each coking coal are as follows: gas coal 5% to 15%, 1 / 3 coking coal 30% to 40%, gas fat coal 5% to 10%, high-sulfur lean coal 10% to 15%, and lean coal 20% to 30%, achieving good results. Patent CN 111621314 B discloses a ramming coal blending coking method, characterized in that fat coal is not blended. The individual coking coals and their weight percentages are as follows: weakly caking coal 5% to 10%, gas coal 0% to 15%, 1 / 3 coking coal 20% to 30%, gas fat coal 8% to 10%, coking coal 25% to 35%, lean coal 10% to 15%, and lean coal 5% to 10%. This invention reduces the consumption of fat coal resources. Although the above technologies have greatly reduced the proportion of coking coal or fat coal, they have not been able to apply gas coal on a large scale, have not fully utilized gas coal resources, and have limited the reduction of coke costs. Summary of the Invention

[0004] Therefore, the purpose of the present invention is to address the problems existing in the above-mentioned prior art, realize the large-scale application of gas coal while ensuring the better quality of coke, reduce the cost of coke, and save high-quality and scarce coking coal resources.

[0005] To achieve the above object, according to one embodiment of the present invention, the present invention provides a method for producing metallurgical coke using a large proportion of gas coal, comprising:

[0006] S1) preparing a single type of coking coal to be mixed: the single type of coking coal and its weight percentage are: gas coal 60%-70%, 1 / 3 coking coal 0%-10%, high sulfur gas fat coal 5%-15%, and lean coal 15%-22%.

[0007] The gas coal, 1 / 3 coking coal, gas fat coal and lean coal are defined in accordance with the classification standard of bituminous coal in GB / T 5751-2009 "China Coal Classification".

[0008] S2) Coal preparation and tamping coking: gas coal is pre-crushed separately, and the proportion of particles less than 3 mm after pre-crushing reaches 80%-85%; coal is then blended and pulverized according to the content of the single coking coal to be mixed in step S1), and the proportion of particles less than 3 mm after pulverization is 86%-88% and the proportion of particles less than 0.5 mm is less than 45%; tamping is then performed, and the tamping bulk density is controlled at 1.0-1.1 t / m 3 ; Then it is produced in a ramming coke oven, with a coking time of 26 to 28 hours. The coke oven standard is 1340~1350℃, and dry quenching is used to obtain metallurgical coke.

[0009] According to one embodiment of the present invention,

[0010] Said gas coal is further divided into first-class gas coal and second-class gas coal;

[0011] The first-class gas coal requires volatile matter V daf is 37% to 40%, and the maximum fluidity α max ≥500ddpm, and the CSR of the coke produced by a 40kg small coke oven alone is ≥35%, and the ash component catalytic index MCI is ≤4%,

[0012] The second-grade gas coal is other gas coal that does not meet the above index requirements, and

[0013] The content of the first-class gas coal is 30% to 40%, and the content of the second-class gas coal is 25% to 30%.

[0014] According to one embodiment of the present invention, the first-class gas coal mines are coal mines in Datong, Shanxi and Yankuang, Shandong.

[0015] According to one embodiment of the present invention,

[0016] The volatile matter V required for the 1 / 3 coking coal is daf is 28% to 35%, and the maximum fluidity α max ≥1500 ddpm, and the CSR of the coke produced by a 40kg small coke oven alone is ≥45%, and the ash component catalytic index MCI is ≤4%.

[0017] According to one embodiment of the present invention,

[0018] One-third of the coking coal mines are located in Xingtai, Hebei and Zaozhuang, Shandong.

[0019] According to one embodiment of the present invention,

[0020] The high sulfur gas fertilizer coal requires volatile matter V daf is 37% to 42%, and the maximum fluidity α max ≥10000ddpm, and sulfur content S t，d The CSR of the coke produced by a 40kg small coke oven alone is ≥40%, and the ash component catalytic index MCI is ≤4%.

[0021] According to one embodiment of the present invention,

[0022] The lean coal requires volatile matter V daf <20%, and the bonding index G value is 10-20.

[0023] According to one embodiment of the present invention,

[0024] The quality indexes of the blended coal obtained by blending the single coking coals meet the following requirements: Volatile matter V daf At 31% to 33%, sulfur content S t，d ≤0.85%, ash content A d ≤10%, maximum fluidity α max ≥200ddpm, ash component catalytic index MCI≤4%.

[0025] According to one embodiment of the present invention,

[0026] The prepared metallurgical coke meets the following quality indicators: sulfur content ≤ 0.70%, ash content ≤ 13%, crushing strength M 25 ≥90%, wear resistance M 10 ≤7%, reactivity CRI≤30%, strength after reaction CSR≥60%.

[0027] Beneficial effects

[0028] The present invention matches gas coals of different qualities, and uses gas-fertilizer coal to replace fertilizer coal to ensure that the bonding and fluidity of the mixed coal meet the requirements, and uses 1 / 3 coking coal to replace coking coal to ensure that the coking and strength of the mixed coal meet the requirements. Under the action of the tamping process, the coking time is appropriately extended and the standard temperature is increased, thereby achieving a large proportion of gas coal, which is 30% to 40% higher than the average level in the industry, and fully utilizing gas coal resources; at the same time, it can greatly reduce or even avoid the use of coking coal and fertilizer coal, and reduce the consumption of scarce coal types.

[0029] Gas coal is 200-300 yuan / ton cheaper than 1 / 3 coking coal, and 500-700 yuan / ton cheaper than coking coal and fat coal. After increasing gas coal by 30%-40%, the cost of coke raw materials can be greatly reduced. The metallurgical coke prepared by the present invention can meet the needs of 1500m 3 And used in blast furnaces. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a comparison chart of coke CSR of gas coal, coking coal and lean coal with and without tamping.

[0031] Figure 2 The coke M of gas coal, coking coal and lean coal is produced by mixing them under tamping and without tamping. 25 Comparison picture. DETAILED DESCRIPTION

[0032] The present invention will be described below by way of examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0033] Process Example

[0034] In order to fully study the application limit of gas coal in ramming coke, a three-coal combination experiment of gas coal, coking coal and lean coal was carried out. Gas coal was selected from Datong area of ​​Shanxi Province, coking coal was selected from Fengfeng coking coal of Handan City, and lean coal was selected from Changzhi area of ​​Shanxi Province. The indicators are shown in Table 1. A 40kg small coke oven experiment was carried out according to the following scheme, as shown in Table 2. The coke quality after the experimental coking is shown in Table 3. Among them, M 25 is the crushing strength of coke, the larger the index, the better, M 10 It is the wear resistance of coke. The smaller the index is, the better.

[0035] The 40kg small coke oven experiment was carried out in accordance with YBT 4526-2016 "Technical Specifications for Small Coke Ovens for Coking Tests", with a coking time of 20 hours and a proportion of coal less than 3mm of 86% to 88%; the bulk density of the tamping process was controlled at 1.0 to 1.1 t / m 3 The bulk density of the non-ramming process is controlled at 0.75~0.78t / m 3 .

[0036] Table 1 Quality indicators of three types of coal

[0037]

[0038] Table 2 Experimental plan

[0039]

[0040] Table 3 Experimental results

[0041]

[0042] It can be seen from Table 2 and Table 3 that under the same process (ramming and non-ramming) conditions, as the proportion of gas coal increases and the proportion of coking coal decreases, the cold strength of coke (M 25 and M 10 ) and hot strength (CRI and CSR) have deteriorated to a certain extent. Figure 1 and Figure 2 It can be seen that under the tamping process, the cold strength of coke (M 25 and M 10 ) and hot strength (CRI and CSR) are still comparable to those of Schemes 5 and 6 without tamping, and CSR can reach more than 60%. 25 Reaching over 90% indicates that the role of gas coal is prominent under the ramming process, allowing its proportion to be expanded. In principle, this is because increasing the bulk density through the ramming process increases the resistance encountered by the gas coal during pyrolysis, delaying its residence time within the colloid. This allows more time for the free radical-bearing atomic groups in the gas or the intermediate products of thermal decomposition to interact with each other, thus overcoming the disadvantage of gas coal's high volatility. Therefore, although the coke strength deteriorates somewhat with increasing gas coal proportions, the strength after this "certain deterioration" under the ramming process still meets the requirements of metallurgical coke.

[0043] Therefore, it is determined to adopt the tamping process. The present invention will be further described in detail below in conjunction with a specific embodiment using the tamping process.

[0044] Example 1:

[0045] Select a single type of coal and its indicators as shown in Table 4.

[0046] Table 4 Coal classification and indicators

[0047]

[0048] The individual types of coal in Table 4 were selected according to the following weight percentages: Class I gas coal 30%, Class II gas coal 30%, 1 / 3 coking coal 1# 10%, high sulfur gas fat coal 1# 10%, lean coal 2# 20%;

[0049] Then, the gas coal is pre-crushed, and the proportion of particles less than 3 mm after pre-crushing reaches 84%; then the mixed coal is crushed, and the proportion of particles less than 3 mm after crushing is 88.5% and the proportion of particles less than 0.5 mm is less than 44%; the quality indicators of the mixed coal obtained after mixing are: volatile matter V daf The content of the raw materials is 32.6%, the sulfur content is 0.81%, the ash content is 9.8%, the bonding index G value is 64, and the maximum fluidity α max is 290ddpm, and the ash component catalytic index MCI is 3.2%;

[0050] Then tamping is carried out and the tamping bulk density is controlled at 1.04t / m 3 ; Produced in a ramming coke oven, the coking time is 26 hours, the coke oven standard is 1340℃, and dry quenching is used.

[0051] The obtained metallurgical coke meets the following quality indicators: sulfur content is 0.68%, ash content is 12.95%, crushing strength M 25 92.8%, wear resistance M 10 The reactivity CRI is 6.9%, the reactivity CRI is 27.4%, and the post-reaction strength CSR is 63.8%, which meet the requirements of metallurgical coke indicators.

[0052] Example 2:

[0053] The individual types of coal in Table 4 are mixed according to the following weight percentages: Class I gas coal 40%, Class II gas coal 30%, high sulfur gas fat coal 1# 10%, lean coal 1# 4%, lean coal 2# 16%;

[0054] Then, the gas coal is pre-crushed, and the proportion of particles less than 3 mm after pre-crushing reaches 82%; then the mixed coal is crushed, and the proportion of particles less than 3 mm after crushing is 88% and the proportion of particles less than 0.5 mm is less than 46%. The quality indicators of the mixed coal obtained after mixing are: Volatile matter V daf At 32.8%, sulfur content 0.85%, ash content 9.75%, bonding index G value 62, maximum fluidity α max 225ddpm, ash component catalytic index MCI is 3.8%;

[0055] Then tamping is carried out and the tamping bulk density is controlled at 1.03t / m 3 ; Produced in a ramming coke oven, the coking time is 26 hours, the coke oven standard is 1340℃, and dry quenching is used.

[0056] The obtained metallurgical coke meets the following quality indicators: sulfur content is 0.70%, ash content is 12.92%, crushing strength M 25 91%, wear resistance M 10 The reactivity CRI is 27.8%, and the post-reaction strength CSR is 62.1%, which meets the requirements of metallurgical coke indicators.

[0057] Example 3:

[0058] The individual types of coal in Table 4 are mixed according to the following weight percentages: Class I gas coal 35%, Class II gas coal 30%, high sulfur gas fat coal 1# 11%, lean coal 2# 24%;

[0059] Then, the gas coal is pre-crushed, and the proportion of particles less than 3 mm after pre-crushing reaches 85%; then the mixed coal is crushed, and the proportion of particles less than 3 mm after crushing is 88.6% and the proportion of particles less than 0.5 mm is less than 46%; the quality indicators of the mixed coal obtained after mixing are: volatile matter V daf At 32.2%, sulfur content 0.84%, ash content 9.83%, bonding index G value 61, maximum fluidity α max It is 215ddpm, and the ash component catalytic index MCI is 3.6%;

[0060] Then tamping is carried out and the tamping bulk density is controlled at 1.04t / m 3 ; Produced in a ramming coke oven, the coking time is 26 hours, the coke oven standard is 1340℃, and dry quenching is used.

[0061] The obtained metallurgical coke meets the following quality indicators: sulfur content is 0.69%, ash content is 12.98%, crushing strength M 25 90.8%, wear resistance M 10 The reactivity CRI is 28.7%, and the post-reaction strength CSR is 61.9%, which meets the requirements of metallurgical coke indicators.

[0062] Example 4:

[0063] The individual types of coal in Table 4 are mixed according to the following weight percentages: Class I gas coal 35%, Class II gas coal 25%, 1 / 3 coking coal 1# 8%, high sulfur gas fat coal 1# 10%, lean coal 1# 5%, lean coal 2# 17%;

[0064] Then, the gas coal is pre-crushed, and the proportion of particles less than 3 mm after pre-crushing reaches 85%; then the mixed coal is crushed, and the proportion of particles less than 3 mm after crushing is 88% and the proportion of particles less than 0.5 mm is less than 45%; the quality indicators of the mixed coal obtained after mixing are: volatile matter V daf At 32.5%, sulfur content 0.84%, ash 9.80%, bonding index G value 63, maximum fluidity α max is 255ddpm, and the ash component catalytic index MCI is 3.4%;

[0065] Then tamping is carried out and the tamping bulk density is controlled at 1.04t / m 3 ; Produced in a ramming coke oven, the coking time is 26 hours, the coke oven standard is 1340℃, and dry quenching is used.

[0066] The obtained metallurgical coke meets the following quality indicators: sulfur content is 0.70%, ash content is 12.93%, crushing strength M 25 91.3%, wear resistance M 10 The reactivity CRI is 27.7%, and the post-reaction strength CSR is 62.9%, which meet the requirements of metallurgical coke indicators.

[0067] Comparative Example 1:

[0068] The individual types of coal in Table 4 are mixed according to the following weight percentages: Class I gas coal 40%, Class II gas coal 35%, 1 / 3 coking coal 1# 5%, high sulfur gas fat coal 1# 5%, lean coal 1# 15%;

[0069] Then, the gas coal is pre-crushed, and the proportion of particles less than 3 mm after pre-crushing reaches 83%; then the mixed coal is crushed, and the proportion of particles less than 3 mm after crushing is 88.2% and the proportion of particles less than 0.5 mm is less than 46%; the quality indicators of the mixed coal obtained after mixing are: volatile matter V daf At 34.8%, sulfur content 0.81%, ash content 9.85%, bonding index G value 66, maximum fluidity α max 260ddpm, ash component catalytic index MCI is 3.3%;

[0070] Then tamping is carried out and the tamping bulk density is controlled at 1.02t / m 3 ; Produced in a ramming coke oven, the coking time is 26 hours, the coke oven standard is 1340℃, and dry quenching is used.

[0071] The obtained metallurgical coke meets the following quality indicators: sulfur content is 0.67%, ash content is 12.95%, crushing strength M 25 The wear resistance is 89.2%, and the wear resistance M 10 The reactivity CRI is 31.2%, and the post-reaction strength CSR is 58.1%, which does not meet the requirements of metallurgical coke indicators.

[0072] The difference of Comparative Example 1 lies in the different proportions of each single type of coal. The total proportion of gas coal in Comparative Example 1 exceeds 70%, which exceeds the gas coal proportion limit, resulting in an imbalance in the overall coal blending structure, causing the volatile matter of the blended coal to rise to more than 34%, a decrease in coking properties, an increase in coke porosity, and a significant decrease in strength, which does not meet the metallurgical coke index requirements.

[0073] Comparative Example 2:

[0074] The individual types of coal in Table 4 are mixed according to the following weight percentages: Class I gas coal 35%, Class II gas coal 30%, high sulfur gas fat coal 2# 14%, lean coal 2# 21%;

[0075] Then, the gas coal is pre-crushed, and the proportion of particles less than 3 mm after pre-crushing reaches 85%; then the mixed coal is crushed, and the proportion of particles less than 3 mm after crushing is 88.6% and the proportion of particles less than 0.5 mm is less than 46%; the quality indicators of the mixed coal obtained after mixing are: volatile matter V daf At 32.6%, sulfur content 0.82%, ash content 9.69%, bonding index G value 63, maximum fluidity α maxis 125ddpm, and the ash component catalytic index MCI is 4.7%;

[0076] Then tamping is carried out and the tamping bulk density is controlled at 1.04t / m 3 ; Produced in a ramming coke oven, the coking time is 26 hours, the coke oven standard is 1340℃, and dry quenching is used.

[0077] The obtained metallurgical coke meets the following quality indicators: sulfur content is 0.66%, ash content is 12.8%, crushing strength M 25 91.0%, wear resistance M 10 The reactivity CRI is 31.5%, and the post-reaction strength CSR is 57.3%, which does not meet the requirements of metallurgical coke indicators.

[0078] The difference between Comparative Example 2 and Example 3 is that Comparative Example 2 uses high-sulfur gas fertilizer coal 2#, whose maximum fluidity is 12560ddpm, which is relatively low, and the ash component catalytic index is 3.99%, which is relatively high, resulting in the fluidity and ash component catalytic index of the blended coal not meeting the blended coal index requirements, causing the coke hot strength CSR to decrease significantly, and not meeting the metallurgical coke index requirements.

[0079] Comparative Example 3:

[0080] The individual types of coal in Table 4 are mixed according to the following weight percentages: Class I gas coal 35%, Class II gas coal 25%, 1 / 3 coking coal 1# 8%, high sulfur gas fat coal 1# 10%, lean coal 1# 5%, lean coal 2# 17%;

[0081] Then, the gas coal is pre-crushed, and the proportion of particles less than 3 mm after pre-crushing reaches 85%; then the mixed coal is crushed, and the proportion of particles less than 3 mm after crushing is 85% and the proportion of particles less than 0.5 mm is less than 43%; the quality indicators of the mixed coal obtained after mixing are: volatile matter V daf At 32.5%, sulfur content 0.84%, ash 9.80%, bonding index G value 63, maximum fluidity α max is 255ddpm, and the ash component catalytic index MCI is 3.4%;

[0082] Then tamping is carried out and the tamping bulk density is controlled at 1.04t / m 3 ; Produced in a ramming coke oven, the coking time is 25 hours, the coke oven standard is 1350℃, and dry quenching is used.

[0083] The obtained metallurgical coke meets the following quality indicators: sulfur content is 0.70%, ash content is 12.93%, crushing strength M 25 The wear resistance is 89.9%, and the wear resistance is M 10 The reactivity CRI is 33.2%, and the post-reaction strength CSR is 58.0%, which does not meet the requirements of metallurgical coke indicators.

[0084] Comparative Example 3 differs from Example 4 in that the proportion of particles smaller than 3 mm after pulverization in Comparative Example 3 is 85%, which is relatively low. The coking time is also low at 25 hours, resulting in production process indicators not meeting requirements. This low proportion of particles smaller than 3 mm indicates insufficient pulverization of large gas coal particles, which can cause coke cracks and affect cold strength. The short coking time also results in insufficient coke maturation, resulting in an increased CRI and a decreased CSR, which does not meet metallurgical coke performance requirements.

Claims

1. A method for producing metallurgical coke using a large proportion of gas coal, comprising: S1) preparing a single type of coking coal to be mixed: the single type of coking coal and its weight percentage are: gas coal 60%-70%, 1 / 3 coking coal 0%-10%, high sulfur gas fat coal 5%-15%, lean coal 15%-22%, The gas coal, 1 / 3 coking coal, gas fat coal and lean coal are defined in accordance with the classification standard of bituminous coal in GB / T 5751-2009 "China Coal Classification". S2) Coal preparation and tamping coking: gas coal is pre-crushed separately, and the proportion of particles less than 3 mm after pre-crushing reaches 80%-85%; coal is then blended and pulverized according to the content of the single coking coal to be mixed in step S1), and the proportion of particles less than 3 mm after pulverization is 86%-88% and the proportion of particles less than 0.5 mm is less than 45%; tamping is then performed, and the tamping bulk density is controlled at 1.0-1.1 t / m 3 Then it is produced in a ramming coke oven with a coking time of 26 to 28 hours. The coke oven standard is 1340 to 1350°C and dry quenching is used to obtain metallurgical coke. The quality indexes of the blended coal obtained by blending the single coking coals meet the following requirements: Volatile matter V daf At 31% to 33%, sulfur content S t，d ≤0.85%, ash content A d ≤10%, maximum fluidity α max ≥200ddpm, ash component catalytic index MCI≤4%, Among them, the prepared metallurgical coke meets the following quality indicators: sulfur content ≤ 0.70%, ash content ≤ 13%, crushing strength M 25 ≥90%, wear resistance M 10 ≤7%, reactivity CRI≤30%, strength after reaction CSR≥60%.

2. The method according to claim 1, wherein Said gas coal is further divided into first-class gas coal and second-class gas coal; The volatile matter V of the first-class gas coal daf is 37% to 40%, and the maximum fluidity α max ≥500ddpm, and the CSR of the coke produced by a 40kg small coke oven alone is ≥35%, and the ash component catalytic index MCI is ≤4%, The second-grade gas coal is other gas coal that does not meet the above index requirements, and The content of the first-class gas coal is 30% to 40%, and the content of the second-class gas coal is 25% to 30%.

3. The method according to claim 2, wherein: The first-class gas coal mines are the coal mines in Datong, Shanxi and the coal mines in Yanzhou, Shandong.

4. The method according to claim 1, wherein The volatile matter V of the 1 / 3 coking coal daf is 28% to 35%, and the maximum fluidity α max ≥1500 ddpm, and the CSR of the coke produced by a 40kg small coke oven alone is ≥45%, and the ash component catalytic index MCI is ≤4%.

5. The method according to claim 1, wherein One-third of the coking coal mines are located in Xingtai, Hebei and Zaozhuang, Shandong.

6. The method according to claim 1, wherein The volatile matter V of the high sulfur gas fertilizer coal daf is 37% to 42%, and the maximum fluidity α max ≥10000ddpm, and sulfur content S t，d The CSR of the coke produced by a 40kg small coke oven alone is ≥40%, and the ash component catalytic index MCI is ≤4%.

7. The method according to claim 1, wherein The volatile matter V of the lean coal daf <20%, and the bonding index G value is 10-20.

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