Coal blending coking method for regulating coke chlorine content

Abstract

This invention belongs to the field of coal blending and coking methods, specifically relating to a method for controlling the chlorine content of coke. It includes the following key steps: Step S1: Prepare coal samples of individual coking coals for blending, and determine the total chlorine content, volatile matter, caking index, and maximum thickness of the plastic layer according to national standards; Step S2: Conduct small-scale coking simulation experiments on the selected individual coals, and determine the total chlorine content, total coke yield, coke reactivity, and post-reaction strength of the resulting coke, calculating the chlorine conversion rate; Step S3: Prepare blended coal by adjusting the coal type ratio based on the coal quality characteristics and the chlorine conversion rate. Using this invention, the chlorine content in coal and coke can be effectively controlled. While ensuring coke quality, it allows for the addition of more high-chlorine coals with price advantages, not only expanding the resources of coking coal but also effectively reducing blending costs.

Description

Technical Field

[0001] This invention belongs to the technical field of coal blending and coking methods, specifically relating to a coal blending and coking method for controlling the chlorine content of coke. Background Technology

[0002] The chlorine content of coal in my country is generally 0.01%–0.2%. The enrichment of chlorine in coal is the result of complex interactions between geological and biochemical processes during its formation. The main sources include the absorption of chlorides (such as Cl-) by coal-forming plants. - Chlorine is primarily derived from the absorption of chlorides in coal and the injection of chloride-rich brine from saline sedimentary environments. Secondary sources mainly involve the circulation of chlorine-containing groundwater during diagenesis, leading to the formation or ion exchange of inorganic chlorides within the coal matrix. Coking coal, as a crucial raw material for iron and steel smelting, directly impacts coke performance and ironmaking efficiency. Chlorine, a typical harmful trace element in coal, migrates and transforms during the high-temperature coking process, distributing in coke, tar, gas, and condensate. This not only causes corrosion of coking oven equipment and a decline in coke's metallurgical performance but also contributes to environmental pollution. Therefore, large domestic steel enterprises (such as Baowu and Ansteel) impose strict limits on the chlorine content of coking coal. However, there is currently a lack of systematic research on the migration behavior of chlorine during coking, especially a lack of experimental data aligned with industrial practices. Studying the chlorine content in coal and its precipitation patterns during coking, and developing optimized coal blending technologies based on the targeted regulation of chlorine migration and transformation to control coke quality, is of paramount importance for controlling and stabilizing the chlorine content of coke. Currently, cost reduction and efficiency improvement remain the key tasks facing most steel and coking plants. Due to the lack of scientific support regarding the transformation law of chlorine in coking coal during the coking process, some coal types cannot be used in large proportions or scientifically.

[0003] Studies such as "The Relationship Between Chlorine Release Characteristics in Coal and Coal Metamorphism" (Coal Quality Technology, 2006(4)) and "Study on Chlorine Release Characteristics in Coal Pyrolysis and Establishment of Chlorine Adsorption Model in Coal" (Clean Coal Technology, 2005(4)) have shown that the higher the volatile matter content in coal during pyrolysis, the higher the chlorine release rate, and the higher the chlorine content in coal, the higher the residual chlorine in coke. However, these conclusions often yield opposite results when guiding coal blending for coking. This may be because modern coking technology uses a wide variety of coking coals, ranging from non-caking coal to anthracite, and the chlorine release patterns may differ depending on the degree of coal metamorphism. In addition, the experimental setups in the literature often employ tubular furnaces, nitrogen purging, and small coal samples, which differ significantly from the pyrolysis process in industrial coking carbonization chambers. Studies have shown that heating temperature, heating rate, pyrolysis atmosphere, and coal type are all key factors affecting chlorine release in coal. Therefore, in order to control the chlorine content in coke, a more scientific and effective coal blending method must be established. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for coking by blending coal to regulate the chlorine content of coke, thereby overcoming the shortcomings of existing theories and technologies. This method enables the scientific and effective use of high-chlorine coal while meeting the quality requirements of high-quality metallurgical coke.

[0005] The technical solution adopted in this invention is a method for coking by blending coal to control the chlorine content of coke, comprising the following key steps: Step S1: Prepare coal samples of the single coking coal in the blended coal, and determine the total chlorine content according to national standards. volatile matter , Adhesion index G, Maximum thickness of adhesive layer Y; The total chlorine content of the single type of coking coal is below 0.15%; Step S2: Conduct small-scale coking simulation tests on the selected single type of coal, and determine the total chlorine content of the resulting coke. Total coke content K, coke reactivity Strength of coke after reaction The conversion rate of chlorine is calculated using the following formula: ; in, The conversion rate of chlorine, The total chlorine content of a single type of coking coal. This refers to the total chlorine content of the corresponding coke; Step S3: Prepare blended coal by adjusting the coal type ratio according to the coal quality characteristics and chlorine conversion rate.

[0006] Furthermore, step S3, coal type ratio control, specifically involves: For two single types of gas-rich coal, A and B, when ,and , ,like Select single-type coal A to participate in coal blending; For two single types of coking coal, C and D, when ,and , ,like Select single-type coal C to participate in coal blending; For two single coal types, E and F, of the same type (1 / 3 coking coal), when ,and ,like Select single-type coal E to participate in coal blending; For two single types of lean coal, G and H, when ,and ,like Select single-type coal G to participate in coal blending; For the two single coal types I and J of coking coal, when ,and ,and ,like Select a single type of coal (I) to participate in coal blending.

[0007] Furthermore, in step S2, the small coke oven used in the simulated coking test is a test coke oven with a capacity of 5-10 kg. The heating curve is as follows: the temperature rises from room temperature to 800℃ in 2 hours, coal is loaded at 800℃ and held for 0.5 hours, then the temperature rises to 1050℃ in 3 hours, and then held for 1 hour.

[0008] Furthermore, it also includes blending coal with 5%–10% gas-rich coal, 28%–40% 1 / 3 coking coal, 13%–18% fat coal, 30%–44% coking coal, and 7%–14% lean coal to obtain blended coal. This blended coal is then crushed, coked, and cooled to obtain coke. The value is 26% to 31%, and the adhesion index G value is 70% to 82%.

[0009] Furthermore, the crushing process ensures that blended coal with a particle size of less than 3 mm accounts for 75% to 80% of the total mass.

[0010] Furthermore, the coking process specifically involves feeding the crushed blended coal into a top-loading coke oven for coking at a temperature of 1000±50℃ for a coking time of 19–24 hours.

[0011] The beneficial effects of this invention are: (1) The method of the present invention is based on a specific small coke oven simulated coking test. It fully considers the influence of experimental conditions such as furnace type, heating temperature, heating rate, pyrolysis atmosphere, and coal type on the release of chlorine in coal, and establishes a more scientific method for determining the chlorine conversion rate of a single type of coal. It overcomes the problem of possible erroneous conclusions caused by the deviation between existing technology and industrial production.

[0012] (2) Based on the relationship between coal quality characteristics and chlorine conversion rate, a scientific and reasonable method for classifying and controlling total chlorine is proposed. This method can not only achieve better substitution of different coal types and effectively control the chlorine content in coal, but also stabilize the quality of coke.

[0013] (3) The method of the present invention, while ensuring the quality of coke, incorporates more high-chlorine coal with price advantages, which not only expands the resources of coking coal, but also effectively reduces the cost of coal blending. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 It is a 5 kg small coke oven test system; The markings shown in the figure are: (1) - coal steamer support, (2) - load trolley, (3) - control system panel, (4) - coke oven main body, (5) - three-stage purification device, (6) - low temperature constant temperature bath. Detailed Implementation

[0016] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0017] This invention provides a method for coking by blending coal to control the chlorine content of coke, comprising the following key steps: Step S1: Prepare coal samples of the single coking coal in the blended coal, and determine the total chlorine content according to national standards. volatile matter , Adhesion index G, Maximum thickness of adhesive layer Y; The total chlorine content of the single type of coking coal is below 0.15%; Step S2: Conduct small-scale coking simulation tests on the selected single type of coal, and determine the total chlorine content of the resulting coke. Total coke content K, coke reactivity Strength of coke after reaction The conversion rate of chlorine is calculated using the following formula: ; in, The conversion rate of chlorine, The total chlorine content of a single type of coking coal. This refers to the total chlorine content of the corresponding coke; It should be further noted that the small coke oven used in the simulated coking test was a test coke oven with a capacity of 5-10 kg. The temperature rise curve was as follows: the temperature rose from room temperature to 800℃ in 2 hours, coal was loaded at 800℃ and held for 0.5 hours, then the temperature rose to 1050℃ in 3 hours, and then held for 1 hour.

[0018] Step S3: Prepare blended coal by adjusting the coal type ratio according to the coal quality characteristics and chlorine conversion rate.

[0019] The specific control of coal type ratio is as follows: For two single types of gas-rich coal, A and B, when ,and , ,like Select single-type coal A to participate in coal blending; For two single types of coking coal, C and D, when ,and , ,like Select single-type coal C to participate in coal blending; For two single coal types, E and F, of the same type (1 / 3 coking coal), when ,and ,like Select single-type coal E to participate in coal blending; For two single types of lean coal, G and H, when ,and ,like Preferably use single-type coal G in coal blending; For the two single coal types I and J of coking coal, when ,and ,and ,like The preferred single type of coal I is used in coal blending.

[0020] This process also includes blending coal by combining 5%–10% gas-rich coal, 28%–40% 1 / 3 coking coal, 13%–18% fat coal, 30%–44% coking coal, and 7%–14% lean coal to obtain blended coal. The blended coal is then crushed so that 75%–80% of the blended coal has a particle size of less than 3 mm. The crushed blended coal is then fed into a top-charged coke oven for coking at a temperature of 1000±50℃ for 19–24 hours. After coking, the coke is cooled to obtain coke.

[0021] It should be further explained that the blended coal mentioned above... The value is 26% to 31%, and the adhesion index G value is 70% to 82%.

[0022] The following examples provide further details.

[0023] Example 1: (1) Prepare coal samples of individual coking coals in the blended coal according to the specifications, and test the total chlorine content separately. Testing was conducted, along with the volatile matter content of other conventional coal process indicators. The bonding index G, maximum thickness Y of the adhesive layer, etc., were tested according to the national standard test methods. The specific values ​​are shown in Table 1.

[0024] (2) Small coke oven simulation coking tests were conducted on the selected single type of coal. The single-coke coking test used a 5kg test coke oven, such as... Figure 1As shown, the coal loading amount in the experiment was 5 kg of air-dried base coal; the coal bulk density was 800 ± 10 kg / m³; the heating curve was as follows: heating to 800℃ in 2 hours, loading coal at 800℃ and holding for 0.5 hours, heating to 1050℃ in 3 hours, and holding at 1050℃ for 1 hour. The coal steamer was then removed and naturally quenched using a sealed dry method. The cooled coke was tested according to standard parameters, including total coke yield (K), coke reactivity (CRI), and coke post-reaction strength (CSR). The total chlorine content of the obtained coke was also measured. Calculate the conversion rate of chlorine. ,in The specific values ​​are shown in Table 1.

[0025] (3) Based on the coal quality characteristics and chlorine conversion rate, the coal type ratio shall be adjusted according to the following rules: For two single types of gas-rich coal, A and B, when ,and , ,like Select single-type coal A to participate in coal blending; For two single types of coking coal, C and D, when ,and , ,like Select single-type coal C to participate in coal blending; For two single coal types, E and F, of the same type (1 / 3 coking coal), when ,and ,like Select single-type coal E to participate in coal blending; For two single types of lean coal, G and H, when ,and ,like Preferably use single-type coal G in coal blending; For the two single coal types I and J of coking coal, when ,and ,and ,like The preferred single type of coal I is used in coal blending.

[0026] (4) The blended coal shall be blended according to the following mass percentage components: 5% to 7% gas-rich coal, 34% to 38% 1 / 3 coking coal, 13% to 14% fat coal, 30% to 35% coking coal, and 12% to 14% lean coal. According to the principle of classification and quality-based blending and control, the specific coal blending scheme and quality control indicators are shown in Table 2.

[0027] (5) Blended coal The content should be controlled between 29% and 31%, and the adhesion index G should be controlled between 75% and 80%.

[0028] (6) After blending, the mixed coal is crushed by a crusher, and the mixed coal with a particle size of less than 3mm accounts for 75% to 78% of its total mass.

[0029] (7) The crushed mixed coal is fed into a 6m top-loading coke oven for coking at a coking temperature of 1050℃ and a coking time of 19 hours.

[0030] (8) After coking, the coke is cooled by dry quenching process.

[0031] Table 1. Coal quality data and coke quality data for a single type of coking coal ; As shown in Table 1, the total chlorine conversion rate varies significantly among different coal types, with no clear pattern. Furthermore, the chlorine conversion rate is generally higher in the 1 / 3 coking coal with higher volatile matter content, while the chlorine conversion rate is lower in the gas-rich coal with the highest volatile matter content. This phenomenon differs from the literature report that "the higher the volatile matter content in coal, the higher the chlorine release rate during pyrolysis." Additionally, while coking coal 10 has the highest chlorine content, the chlorine content in its coke is relatively low, which also contradicts the literature report that "the higher the chlorine content in coal, the higher the residual chlorine in coke." Therefore, overall, the experimental method proposed in this invention is more scientific, reasonable, and effective in guiding the optimization of coal blending.

[0032] Based on the principle of controlling chlorine levels according to coal classification and quality, Table 2 presents four schemes as examples for comparison.

[0033] Table 2 Coking Coal Blending Scheme and Quality Data Table ; Compared with Scheme 1, Scheme 2 replaces Gas-Fertilizer Coal 1 with Gas-Fertilizer Coal 2.

[0034] For two single coal types 1 and 2 in gas-rich coal: ; ; ; ; Gas-rich coal type 2 has a low chlorine content but a high conversion rate. Therefore, compared with type 2, scheme 1 not only increases the use of high-chlorine coal, but also produces coke with a lower chlorine content, ensuring coke quality.

[0035] Compared to Option 3, Option 1 uses 13% of 1 / 3 coking coal 3, reducing 1 / 3 coking coal 4. Regarding the two single coal types 3 and 4 within the 1 / 3 coking coal: ; ; ; 1 / 3 coking coal 3 has a high chlorine content but a low conversion rate. Therefore, compared with Scheme 3, Scheme 1 uses 13% 1 / 3 coking coal 3 and reduces 1 / 3 coking coal 4, which not only increases the use of high-chlorine coal, but also reduces the chlorine content of the coke produced, and slightly improves the quality of the coke.

[0036] Compared with Scheme 4, Scheme 1 appropriately increases coking coal by 10 and decreases coking coal by 13.

[0037] For two single coal types, 10 and 13, in coking coal: ; ; ; ; Because coking coal 10 has the highest chlorine content but the lowest conversion rate, compared with Scheme 4, Scheme 1 appropriately increases coking coal 10 and reduces coking coal 13. This not only improves the use of high-chlorine coal, but also reduces the chlorine content of the coke produced, thus ensuring coke quality.

[0038] In summary, the technical solution of this invention can not only reasonably incorporate high-chlorine coal with price advantages, but also effectively control the chlorine content in coke, and stabilize coke quality.

[0039] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present technical solution are within the protection scope of the present invention.

[0040] To facilitate understanding by those skilled in the art of the improvements of this invention over the prior art, some of the accompanying drawings and descriptions have been simplified, and for clarity, some other elements have been omitted from this application. Those skilled in the art should realize that these omitted elements may also constitute the content of this invention.

Claims

1. A method for coking by blending coal to control the chlorine content of coke, characterized in that, The key steps include the following: Step S1: Prepare coal samples of the single coking coal in the blended coal, and determine the total chlorine content according to national standards. volatile matter , Adhesion index G, Maximum thickness of adhesive layer Y; The total chlorine content of the single type of coking coal is below 0.15%; Step S2: Conduct small-scale coking simulation tests on the selected single type of coal, and determine the total chlorine content of the resulting coke. Total coke content K, coke reactivity Strength of coke after reaction The conversion rate of chlorine is calculated using the following formula: ； in, The conversion rate of chlorine, The total chlorine content of a single type of coking coal. This refers to the total chlorine content of the corresponding coke; Step S3: Prepare blended coal by adjusting the coal type ratio according to the coal quality characteristics and chlorine conversion rate.

2. The method for regulating the chlorine content of coke in coal blending as described in claim 1, characterized in that, The specific steps of coal type ratio control in step S3 are as follows: For two single types of gas-rich coal, A and B, when ,and , ,like Select single-type coal A to participate in coal blending; For two single types of coking coal, C and D, when ,and , ,like Select single-type coal C to participate in coal blending; For two single coal types, E and F, of the same type (1 / 3 coking coal), when ,and ,like Select single-type coal E to participate in coal blending; For two types of lean coal, G and H, when ,and ,like Select single-type coal G to participate in coal blending; For the two single coal types I and J of coking coal, when ,and ,and ,like Select a single type of coal (I) to participate in coal blending.

3. The method for regulating the chlorine content of coke in coking as described in claim 2, characterized in that, In step S2, the small coke oven used in the simulated coking test is a test coke oven with a capacity of 5-10 kg. The temperature rise curve is as follows: the temperature rises from room temperature to 800℃ in 2 hours, coal is loaded at 800℃ and held for 0.5 hours, then the temperature rises to 1050℃ in 3 hours, and then held for 1 hour.

4. A method for coking by blending coal to regulate the chlorine content of coke as described in any one of claims 1-3, characterized in that, This also includes blending coal with 5%–10% gas-rich coal, 28%–40% 1 / 3 coking coal, 13%–18% fat coal, 30%–44% coking coal, and 7%–14% lean coal to obtain blended coal. The blended coal is then crushed, coked, and cooled to obtain coke. The value is 26% to 31%, and the adhesion index G value is 70% to 82%.

5. The method for coking by blending coal to regulate the chlorine content of coke as described in claim 4, characterized in that, Crushing results in blended coal with a particle size of less than 3 mm accounting for 75% to 80% of the total mass.

6. The method for coking by blending coal to regulate the chlorine content of coke as described in claim 4, characterized in that, The coking process specifically involves feeding crushed blended coal into a top-loading coke oven for coking at a temperature of 1000±50℃ and a coking time of 19–24 hours.

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