Coal blending coking method for controlling coke quality

Abstract

The invention discloses a coal blending coking method for controlling coke quality, and mainly solves the technical problems of large quality fluctuation and quality deterioration of coke obtained through index coal blending in the prior art. According to the technical scheme, the coal blending and coking method for controlling the coke quality comprises the following steps: 1) carrying out a small coke oven coking test on a new coal type C new, and detecting the post-reaction strength CSR new of single coke obtained by smelting the new coal type; 2) determining the coal blending coking ratio of the new coal type; 3) blending coal, namely blending the coal according to the coal blending coking ratio of the new coal type to obtain blended coal; 4) crushing the mixed coal; (5) coking the mixed coal: feeding the crushed mixed coal into a top-charging coke oven for coking at the coking temperature of 950-1050 DEG C for 21-23 hours; and 6) cooling the coke after discharging the coke. According to the invention, stable control of coke quality is realized, the produced coke is high-strength metallurgical coke, and the strength CSR of the coke after reaction is 68-70%.

Description

Technical Field

[0001] The invention relates to a coal blending coking method, in particular to a coal blending coking method for controlling coke quality, and belongs to the technical field of coal chemical industry. Background Art

[0002] In the process of metallurgical coke production, coal blending and coking technology is a key technology, which not only determines the quality of coke, but also determines the cost of coal blending on the basis of ensuring the quality of coke. The strength of coke after reaction reflects the metallurgical properties of coke in the blast furnace. Large blast furnace ironmaking puts forward higher requirements on the stability of the strength of coke after reaction. The fluctuation of the strength of coke after reaction may bring about the fluctuation of the blast furnace condition and affect the smooth operation of the blast furnace. Therefore, it is of great significance to stabilize the strength of coke after reaction.

[0003] The post-reaction strength of coke is a comprehensive indicator. To obtain higher post-reaction strength of coke, a higher cold drum strength is generally required as a basis. In order to stabilize key technical indicators such as post-reaction strength of coke, various companies generally adopt index coal blending technology.

[0004] The Chinese patent application document with application publication number CN107794071A discloses a coal blending method for stabilizing the quality of coke, which closely combines the coal rock analysis method with the traditional coal blending method, supplemented by the small coke oven independent coal blending coking experiment, and compares all the measured data in detail to obtain a more reasonable coal blending plan. The indicators used include industrial analysis of various coking coals, G, Y value determination and coal rock analysis, and small coke oven single coal independent coking experiment; the method uses coal rock analysis data and small coke oven coking experiment, but the method is still indicator coal blending; on the basis of the existing coal blending ratio, the coal type is changed or the coal blending ratio of each coal type is adjusted to form a coal blending ratio plan; according to the additivity principle, the industrial analysis of the blended coal and the G, Y value prediction are carried out, and the maximum vitrinite reflectance and distribution map of the blended coal are drawn to formulate a theoretical coal blending report; that is, the above-mentioned coal blending indicators are controlled to control the stability of coke quality.

[0005] The Chinese patent application document with application publication number CN104655819A discloses a method for predicting the thermal reactivity of coke, comprising the following steps: 1) determining the ash composition of each single type of coal used for coking, and calculating the basicity index MCI of the blended coal; 2) determining the optical structure of the coke formed by each single type of coal used for coking, and calculating the sum of the contents of coarse-grained mosaic, medium-grained mosaic, incomplete fiber, fiber and flaky components in the blended coal M; 3) setting CRI=A+B*MCI+C*M, where CRI is the thermal reactivity of coke, in units of %; A, B, and C are constants; 4) calculating the predicted value of the thermal reactivity CRI of coke; this method uses microscopic indicators such as the ash composition and optical structure of coal, which are actually no different from the macroscopic indicators of control, and still predicts the quality of coke through indicator control, which cannot avoid the fluctuation of the quality of coke. Due to the complexity of coking coal, the indicators used are complicated, there are many interference factors in the prediction of coke quality, and the evaluation cycle is long, which makes it difficult to directly guide production.

[0006] The existing coal blending coking method has the technical problems of uncertainty in predicting the thermal strength index of coke, and large fluctuations and quality degradation of the coke obtained by blending coal by the index. Summary of the invention

[0007] The purpose of the present invention is to provide a coal blending coking method for controlling the quality of coke, mainly to solve the technical problems of large quality fluctuation and quality deterioration of coke obtained by index coal blending in the prior art.

[0008] The technical idea of ​​the present invention is to, through gradual substitution, firstly, conduct a small coke oven coking test on the new coal; secondly, determine a new coal blending ratio scheme based on the basic coal blending ratio; thirdly, carry out coal blending coking under the new coal blending ratio; after using the new coal, produce high-quality metallurgical coke with stable quality on the top-loading coke oven.

[0009] The technical solution adopted by the present invention is a coal blending coking method for controlling the quality of coke, comprising the following steps:

[0010] 1) For new coal type C 新 Conduct a small coke oven coking test to determine the type of new coal according to China's coal classification standards; use a test coke oven with a single coal consumption of 70-100kg to coke the new coal separately to obtain a single type of coke, and test the post-reaction strength (CSR) of the single type of coke obtained from the new coal 新 ;

[0011] 2) Determine the coking ratio of the new coal, determine the coal ratio under the existing coke quality as the basic coal, and compare the post-reaction strength CSR of the single coke obtained by smelting the new coal 新 Target alternative coal type C in basic coal blending 目标 The post-reaction strength CSR of the single coke obtained by smelting 目标:When CSR 新 ≥CSR 目标 , new coal type C 新 Proportion = target alternative coal type C 目标 Ratio; when CSR 新 <CSR 目标 , new coal type C 新 Proportion = target alternative coal type C 目标 Proportion × r, coal C 高 Increased value of the proportion = target alternative coal type C 目标 Ratio × (1-r); r = (CSR 高 -CSR 目标 ) / (CSR 高 -CSR 新 ); the coal C 高 Refers to the new coal type C in the basic coal blending 新 The coal with the highest reaction strength of the single type of coke produced from the same type of coal; CSR 高 Coal C 高 The post-reaction strength of a single type of coke obtained by smelting;

[0012] 3) Coal blending, blending coal according to the coking ratio of the new coal to obtain blended coal;

[0013] 4) crushing the blended coal, crushing the blended coal;

[0014] 5) Coal coking: the crushed coal is sent to the top-loading coke oven for coking. The coking temperature is 950-1050°C and the coking time is 21-23 hours;

[0015] 6) Cooling the coke after decoking.

[0016] Furthermore, after the blended coal is crushed, the proportion of the blended coal with a particle size of less than 3 mm accounts for 75% to 80% of its total mass.

[0017] The coke produced by the method of the present invention is high-strength metallurgical coke, with a coke reactivity CRI of 21-23%, a coke post-reaction strength CSR of 68-70%, and a coke drum strength of 1.5-2.0. 88-90%, coke crushing strength M 40 88-90%, coke wear resistance M 10 It is 5.6~6.0%.

[0018] After years of research, the applicant has found that due to the complexity of coking coal, it is difficult to find a one-to-one correspondence between coking coal blending indicators and coke quality indicators. Often, the coking coal blending indicators are the same but the coke quality varies greatly. There is a certain risk of coke quality fluctuations when controlling coke quality through coal blending indicators.

[0019] The invention adopts progressive substitution, and fine-tunes the new type of coking coal based on the existing coal blending to meet the coke quality requirements, thereby maintaining the strong coal-bonding skeleton effect of high-quality coking coal in the coal blending, thereby ensuring uniform and stable pores during the coke formation process, thereby ensuring stable coke quality.

[0020] Compared with the prior art, the present invention has the following positive effects: 1. The present invention realizes the stable control of coke quality, breaks through the limitations of the traditional index coal blending method, proposes corresponding replacement ratios based on the performance of alternative coal types and the characteristics of coking coal and alternative coal types, uses progressive substitution, and reasonably adjusts the coal blending ratio to achieve stable control of the strength of coke after reaction, ensuring that the coke meets the needs of blast furnace ironmaking. 2. The method of the present invention is easy to implement. The progressive coking coal substitution coal blending method provided by the present invention can produce coke in ordinary top-loading coke ovens that meet the quality requirements of high-quality metallurgical coke; the coke produced is high-strength metallurgical coke, with a coke reactivity CRI of 21-23%, a coke post-reaction strength CSR of 68-70%, and a coke drum strength DI1155. 0 88-90%, coke crushing strength M 40 88-90%, coke wear resistance M 10 It is 5.6~6.0%. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the embodiments, as shown in Table 1.

[0022] Embodiment A new type of coal is substituted for coking coal, and coking is carried out in a 7m top-loading coal coke oven to obtain coke with stable quality.

[0023] A coal blending coking method for controlling coke quality comprises the following steps:

[0024] 1) For new coal type C 新 Conduct a small coke oven coking test to determine the type of new coal according to the Chinese coal classification standard GB / T 5717-2009; use a test coke oven with a single coal consumption of 70kg to coke the new coal to obtain a single type of coke, and test the post-reaction strength (CSR) of the single type of coke obtained from the new coal 新 ;

[0025] 2) Determine the coking ratio of the new coal, determine the coal ratio under the existing coke quality as the basic coal, and compare the post-reaction strength CSR of the single coke obtained by smelting the new coal 新 Target alternative coal type C in basic coal blending 目标 The post-reaction strength CSR of the single coke obtained by smelting 目标 :When CSR 新 ≥CSR 目标 , new coal type C 新 Proportion = target alternative coal type C目标 Ratio; when CSR 新 <CSR 目标 , new coal type C 新 Proportion = target alternative coal type C 目标 Proportion × r, coal C 高 Increased value of the proportion = target alternative coal type C 目标 Ratio × (1-r); r = (CSR 高 -CSR 目标 ) / (CSR 高 -CSR 新 ); the coal C 高 Refers to the new coal type C in the basic coal blending 新 The coal with the highest reaction strength of the single type of coke produced from the same type of coal; CSR 高 Coal C 高 The post-reaction strength of a single type of coke obtained by smelting;

[0026] 3) Coal blending, blending coal according to the coking ratio of the new coal to obtain blended coal;

[0027] 4) 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 accounts for 75% to 80% of its total mass;

[0028] 5) Coal coking: the crushed coal is sent to the top-loading coke oven for coking. The coking temperature is 1000°C and the coking time is 21 to 23 hours.

[0029] 6) Cooling the coke after decoking.

[0030] The performance parameters of the blended coal in the embodiment are shown in Table 1; the specific proportions of the blended coal in the embodiment are shown in Table 1.

[0031] Table 1 Mass percentage of coking blended coal and coke performance parameters of the embodiments of the present invention

[0032]

[0033] As shown in Table 1, in the embodiment of the present invention, the new coal type C 新 For coking coal, CSR 新 Among the basic coal blending ratios, the coking coal with the highest CSR after coke reaction is JM7, i.e., coal C 高 For JM7, CSR 高 It is 72.2%.

[0034] As shown in Table 1, in Scheme 1, the new coal type C 新 The target coal type C 目标 The coke strength after reaction of JM2 is 61.6%, that is, CSR目标 is 61.6%; when new coal type C 新 When replacing coking coal JM2, due to CSR 新 63%, CSR 目标 is 61.6%, at this time CSR 新 ≥CSR 目标 , replace the target alternative coal type JM2 with a new coal ratio of 6%.

[0035] As shown in Table 1, in Scheme 2, the new coal type C 新 The target coal type C 目标 The coke strength after reaction of JM4 is 66%, that is, CSR 目标 is 66%; when new coal type C 新 When replacing coking coal JM4, CSR 新 is 63% less than CSR 目标 66%; increase coal C 高 The ratio of CSR 高 is 72.2%, that is, the proportion of coking coal JM7 is increased, and the CSR of JM7 is 72.2%, r = (CSR 高 -CSR 目标 ) / (CSR 高 -CSR 新 )=(72.2%-66%) / (72.2%-63%)=0.67, new coal ratio=JM4 ratio 6%×0.67=4%, coal C 高 The increase in the proportion = JM4's proportion 6% × (1-0.67) = 2%, that is, the increase in the JM7 proportion is 2%, and the original proportion of the basic coal proportion JM7 is 10%; after adding the new coal type, the proportion of JM7 is 12%.

[0036] As shown in Table 1, the high-strength metallurgical coke produced in embodiments 1 and 2 has a coke reactivity CRI of 21-23%, a coke post-reaction strength CSR of 68-70%, and a coke drum strength 88-90%, coke crushing strength M 40 88-90%, coke wear resistance M 10 It is 5.6~6.0%.

[0037] Through the above-mentioned proportion adjustment, the quality data of coke obtained under the new proportion scheme are basically the same as the data measured under the benchmark scheme, thus maintaining the stability of coke quality.

[0038] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A method for coking by blending coal for controlling the quality of coke, characterized in that: The following steps are involved: 1) For new coal type C 新 Conduct a small coke oven coking test to determine the type of new coal according to China's coal classification standards; use a test coke oven with a single coal consumption of 70-100kg to coke the new coal separately to obtain a single type of coke, and test the post-reaction strength (CSR) of the single type of coke obtained from the new coal 新 ; 2) Determine the coking ratio of the new coal, determine the coal ratio under the existing coke quality as the basic coal, and compare the post-reaction strength CSR of the single coke obtained by smelting the new coal 新 Target alternative coal type C in basic coal blending 目标 The post-reaction strength CSR of the single coke obtained by smelting 目标 :When CSR 新 ≥CSR 目标 , new coal type C 新 Proportion = target alternative coal type C 目标 Ratio; When CSR 新 <CSR 目标 , new coal type C 新 Proportion = target alternative coal type C 目标 Proportion × r, coal C 高 Increased value of the proportion = target alternative coal type C 目标 Ratio × (1-r); r = (CSR 高 -CSR 目标 ) / (CSR 高 -CSR 新 ); the coal C 高 Refers to the new coal type C in the basic coal blending 新 The coal with the highest reaction strength of the single type of coke produced from the same type of coal; CSR 高 Coal C 高 The post-reaction strength of a single type of coke obtained by smelting; 3) Coal blending, blending coal according to the coking ratio of the new coal to obtain blended coal; 4) crushing the blended coal, crushing the blended coal; 5) Coal coking: the crushed coal is sent to the top-loading coke oven for coking. The coking temperature is 950-1050°C and the coking time is 21-23 hours; 6) Cooling the coke after decoking.

2. The method for coking by blending coal for controlling the quality of coke according to claim 1, characterized in that: After the blended coal is crushed, the proportion of the blended coal with a particle size of less than 3 mm accounts for 75% to 80% of its total mass.

3. The method for coking by blending coal for controlling coke quality according to claim 1, characterized in that: The coke reactivity CRI is 21-23%, the coke strength after reaction CSR is 68-70%, and the coke drum strength 88-90%, coke crushing strength M 40 88-90%, coke wear resistance M 10 It is 5.6~6.0%.

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