Method for estimating coke resistance of coke mixture after reaction with co2, method for producing coke from coke mixture, method of operating a coke oven, and method for controlling the mixture proportions of individual coals

Description

1 / 18 METHOD FOR ESTIMATING COKE RESISTANCE OF COKE MIXTURE AFTER REACTION WITH CO2, METHOD FOR PRODUCING COKE FROM COKE MIXTURE, METHOD OF OPERATING A COKE OVEN, AND METHOD FOR CONTROLLING THE MIXTURE PROPORTIONS OF INDIVIDUAL COALS FIELD OF TECHNIQUE

[001] The present invention relates to a method for readily estimating the strength of coal-mixed coke after reaction with CO2. PREVIOUS TECHNIQUE

[002] Blast furnaces are traditionally charged with iron raw materials, such as iron ores, and also coke as auxiliary raw materials. To produce coke of the desired quality, coals of different qualities are mixed to adjust the content, and the resulting coal mixture is pulverized and carbonized in a coke oven. The coals (coal marks) before mixing are referred to as individual coals.

[003] Since coke quality has a significant effect on blast furnace operation, stable production of high-quality coke is necessary. In particular, coke plays an important role in ensuring gas permeability in a blast furnace. Therefore, it is important to produce high-strength coke to eliminate or reduce the generation of a dust that will inhibit gas passage in the blast furnace. The impact applied to the coke varies according to the location in a blast furnace. Thus, coke strength is controlled by means of strength indices, such as the drum index (DI) and coke strength after reaction with CO2 (CSR).

[004] In particular, the resistance of coke after reaction with CO2 (CSR) is used as an index of resistance to susceptibility to Petition 870250088713, dated 09 / 30 / 2025, page 8 / 36 2 / 18 Coke deteriorates through hot reaction with CO2 in a blast furnace. The CSR measurement is specified in ISO 18894 and is defined as follows: 200 g of coke with a particle size adjusted to 20 ± 1 mm is reacted at 1100 °C for 2 hours while there is a flow of 100% CO2 gas at 5 L / min. The reacted coke is treated for 600 rotations in a type I drum tester and is sieved through a 9.56 mm sieve. The mass yield of the coke remaining on the sieve is taken as the CSR. The percent weight loss of the coke before and after the reaction at 1100 °C for 2 hours is specified as the coke reactivity index (CRI) in ISO 18894.

[005] Due to the characteristics of the measurement technique, the resistance of coke after reaction with CO2 (CSR) can be estimated from the drum index (DI) of the coke before the reaction and the coke reactivity index (CRI). The CSR has a particularly high correlation with the CRI. Therefore, estimating the coke reactivity index (CRI) of coal-mixed coke is important for estimating the resistance of coal-mixed coke after reaction with CO2 (CSR).

[006] Patent Literature 1 proposes a technique for estimating the coke strength of coal-mixed coke after reaction with CO2. In the technique, the weighted average of the CSRs of the individual coals multiplied by the mixing ratios is corrected based on the effects of coal mixing, specifically, the overlap of the thermoplastic regions of the coals measured by the Gieseler Plastometer method, the total average reflectance and the maximum flowability.

[007] Furthermore, Patent Literature 2 proposes a technique for estimating the coke reactivity index of a coal-mixed coke. In the technique, the coke reactivity indices of an individual coal coke are multiplied by the proportions of Petition 870250088713, dated 09 / 30 / 2025, page 9 / 36 3 / 18 mixture of the respective individual coals and the resulting weighted average is corrected for specific volume.

[008] Patent Literatures 3 and 4 propose techniques for estimating the CSR of coal blended coke from the CRI of the coal blended coke calculated as the weighted average of the CRIs of the individual coal cokes and the cold surface fracture resistance DI1506. LIST OF QUOTES Patent Literature

[009] PTL 1: Publication of Unexamined Japanese Patent Application No. 63-199286

[0010] PTL 2: Publication of Unexamined Japanese Patent Application No. 9-263766

[0011] PTL 3: Publication of Unexamined Japanese Patent Application No. 2005-232350

[0012] PTL 4: Publication of Unexamined Japanese Patent Application No. 2013-1895 SUMMARY OF THE INVENTION Technical Problem

[0013] Many of the above techniques for estimating the coke strength of coal blended coke after reaction with CO2 (CSR) assume that the CSRs and CRIs of individual coal cokes have been measured. However, CSR and CRI measurements are time-consuming. Due to this fact, estimating the coke strength of coal blended coke after reaction with CO2 (CSR) has a disadvantage, as it requires a prolonged time to prepare individual coal cokes from all coal grades that have arrived at the stockpile and to measure the CSR and CRI of each individual coal coke. Furthermore, the CRI is affected by other factors, such as residual volatile matter (VM) in the coke, and therefore the Petition 870250088713, dated 09 / 30 / 2025, page 10 / 36 4 / 18 Measurement results may include variations.

[0014] One objective of the present invention is to provide a method for readily estimating the coke strength of coal-mixed coke after reaction with CO2. Solution to the Problem

[0015] The present invention is directed to estimating the coke strength of coal-mixed coke after reaction with CO2 (CSR) ready and simply using thermogravimetry. The present invention has the following configurations.

[0016] [1] A method for estimating the CSR of coal blend coke to estimate the coke resistance of a coal blend coke after reaction with CO2 (CSR) using a reactivity index TG which is a percentage of weight loss measured by thermogravimetry of the coke held in a CO2 atmosphere in a predetermined temperature range for a predetermined time, the method including: One step involves measuring the TG reactivity indices of individual coal cokes and estimating the TG reactivity index of the corresponding coal coke mixture from the weighted average of the measured TG reactivity indices of the individual coal cokes; One step involves estimating the coke reactivity index (CRI) of the coal-mixed coke from the TG reactivity index of the coal-mixed coke estimated in the previous step; and another step involves estimating the coke resistance of the coal-mixed coke after reaction with CO2 (CSR) from the coke reactivity index (CRI) of the coal-mixed coke estimated in the previous step and the drum index (DI) of the coal-mixed coke.

[0017] [2] The method for estimating the CSR of coal-mixed coke according to [1], wherein thermogravimetry is performed to Petition 870250088713, dated 09 / 30 / 2025, page 11 / 36 5 / 18 heat the coke in an inert gas atmosphere in a temperature range of 950 °C to 1100 °C.

[0018] [3] The method for estimating the CSR of coal-mixed coke according to [1] or [2], where the predetermined time is 10 minutes or more and 120 minutes or less.

[0019] [4] A method for producing coal-mixed coke that includes: to estimate the strength of the coke from coal blended coke after reaction with CO2 using the CSR estimation method for coal blended coke described in any of [1] to [3]; and to change a production condition based on the estimated strength of the coke from coal blended coke after reaction with CO2.

[0020] [5] A method of operating a coke oven that includes: to estimate the strength of the coke from the coal blend coke after reaction with CO2 using the CSR estimation method for coal blend coke described in any one of [1] to [3]; and to change a coke oven operating condition based on the estimated strength of the coke from the coal blend coke after reaction with CO2.

[0021] [6] A method for controlling the coal mixing ratios of individual coals which includes: estimate the coke strength of the coal blend coke after reaction with CO2 using the method for estimating the CSR of coal blend coke described in any one of [1] to [3]; and alter the blending ratios of individual coals based on the estimated coke strength of the coal blend coke. Petition 870250088713, dated 09 / 30 / 2025, page 12 / 36 6 / 18 after the reaction with CO2. Advantageous Effects of the Invention

[0022] The present invention allows a quick estimation of the coke strength of coal-mixed coke after reaction with CO2 (CSR).

[0023] According to the present invention, the percentage weight losses (reactivity indices TG) of individual coal cokes are measured by thermogravimetry and the reactivity indices TG are weighted averaged to provide the reactivity index TG of the corresponding coal blend coke which is then converted to the coke reactivity index (CRI) of the coal blend coke. After the coke reactivity index (CRI) of the coal blend coke is then determined, the coke strength of the coal blend coke after reaction with CO2 (CSR) is estimated from the coke reactivity index (CRI) of the coal blend coke and the drum index (DI) of the coal blend coke. In this way, the coke strength of the coal blend coke after reaction with CO2 can be easily estimated. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a graph illustrating the relationships between the weighted average of the measured TG reactivity indices of the individual coal cokes and the measured TG reactivity index of the corresponding coal blend coke.

[0025] Figure 2 is a graph illustrating the relationships between the estimated TG reactivity index of coal-mixed coke and the actually measured coke reactivity index (CRI) of coal-mixed coke.

[0026] Figure 3 is a graph illustrating the relationship between coke resistance after reaction with CO2 (CSR) and the coke reactivity index (CRI) for various coke drum indices (DI). Petition 870250088713, dated 09 / 30 / 2025, page 13 / 36 7 / 18

[0027] Figure 4 is a graph illustrating the relationship between the estimated coke strength of coal-mixed coke after reaction with CO2 (CSR) and the actually measured coke strength of coal-mixed coke after reaction with CO2 (CSR). DESCRIPTION OF THE MODALITIES

[0028] The embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments.

[0029] As already mentioned, the resistance of coke after reaction with CO2 (CSR) is controlled by the coke reactivity index (CRI) and the coke drum index (DI). Thus, the resistance of coal-mixed coke after reaction with CO2 (CSR) can be estimated if the coke reactivity index (CRI) of coal-mixed coke and the drum index (DI) of coal-mixed coke are available.

[0030] First, a process for estimating the coke reactivity index (CRI) of coal blend coke will be described. In the present embodiment, the coke reactivity index (CRI) of coal blend coke is estimated by means of the following steps. The first step measures the percentage of weight losses of the individual coal cokes (the TG reactivity indices of the individual coal cokes) by means of thermogravimetry, in which the individual coal cokes are maintained in a CO2 atmosphere within a predetermined temperature range for a predetermined time. The next step estimates the corresponding coal blend coke reactivity index (TG) from the weighted average of the TG reactivity indices of the individual coal cokes measured in the previous step. The subsequent step estimates the coke reactivity index (CRI) of the coal blend coke from the TG reactivity index of the coal blend coke estimated in the previous step. Petition 870250088713, dated 09 / 30 / 2025, page 14 / 36 8 / 18 interior. These steps will be described individually below. Step for measuring the percentage of weight loss of individual coal cokes (the TG reactivity indices of the individual coal cokes).

[0031] This step uses thermogravimetry (TG). Thermogravimetry is able to measure the change in weight over time (the percentage of weight loss) resulting from the reaction of carbon in coke with CO2 in a high-temperature atmosphere with 100% CO2. Since the weight loss of coke due to this reaction is linear, it is possible to estimate the coke reactivity index (CRI) of the coal-mixed coke, which will be described later, even when the reaction time (the measurement time) is short.

[0032] In this descriptive report, the percentage of weight loss measured by thermogravimetry in which coke is kept in a CO2 atmosphere within a predetermined temperature range for a predetermined time is also written as the TG reactivity index.

[0033] In this step, the percentage of weight losses of individual coal cokes (the TG reactivity indices of individual coal cokes) is measured by means of TG, in which the individual coal cokes are maintained in a CO2 atmosphere within a predetermined temperature range for a predetermined time. The TG measurement is performed with a TG device. The individual coal cokes used as samples for TG can be cokes obtained by carbonization of individual coals. For example, individual coal cokes prepared through a can carbonization test can be used, or small quantities of samples obtained through sample splitting can be carbonized under predetermined conditions to generate individual coal cokes. Samples for TG can be collected from any Petition 870250088713, dated 09 / 30 / 2025, page 15 / 36 9 / 18 method, without limitation. The sample quantity is limited by the specifications of the TG device. To increase measurement accuracy, sampling preferably ensures that the sample exhibits representative properties of the individual coal coke. For example, it is preferable that the sampling conforms to Coal and Coke - Sampling and Sample Preparation in the JIS M 8811: 2000 standard.

[0034] The amount of sample to be subjected to TG measurement can be adjusted to the capacity and size of the TG device. It is preferable that the particle size of the TG sample be determined in such a way that the sample contains a certain number of particles sufficient to be representative. From this point of view, the particle size of the single coal coke used as the sample is preferably 850 μm or less. The particle size can be controlled by pulverizing the individual coal coke. Furthermore, the specific surface area of ​​the sample influences the reaction with CO2 and, in particular, the amount of fine particles contained in the sample greatly affects the specific surface area of ​​the sample. Therefore, it is preferable to remove fine particles with a particle size smaller than 200 μm. From the above points of view, the particle size of the sample is preferably 200 μm or more and 850 μm or less.The particle size of the sample for TG can be controlled by sieving the pulverized individual coal coke through a sieve with a predetermined mesh size.

[0035] Next, the TG measurement conditions will be described. The TG measurement is performed as follows. The sample is placed in the TG device and heated to a predetermined temperature range in an inert gas atmosphere, such as nitrogen. The sample is then held in a CO2 atmosphere for a predetermined time. Specifically, after the sample has been Petition 870250088713, dated 09 / 30 / 2025, page 16 / 36 10 / 18 heated to a predetermined temperature range in an inert gas atmosphere, the gas supplied to the TG device is changed to gaseous CO2 and the sample is kept in a CO2 atmosphere for a predetermined time and then analyzed by TG. The heating rate in the above process can be controlled according to the capacity of the TG device. A higher heating rate leads to a shorter measurement time and is therefore preferable. From this point of view, the heating rate is preferably 20 °C / min or more. The maximum limit of the heating rate is not particularly limited and is a heating rate such that the heating process will not exceed the temperature control capacity of the device and will not raise the temperature above the predetermined temperature range. As an example, the heating rate could be 150 °C / min or less.The gaseous CO2 feed rate is preferably sufficient to ensure that the gaseous CO2 feed during the reaction does not limit the reaction rate. The gaseous CO2 feed rate that does not limit the reaction rate varies depending on the sample quantity and the size of the TG device. Therefore, it is preferable to determine beforehand the gas feed rate that is required for the actual TG device. For example, the gaseous CO2 feed rate is preferably 500 mL / min or more in the case of a general TG device to analyze approximately several tens of mg of a measurement sample.

[0036] From the point of view focused on the reactivity of the coke matrix, the predetermined temperature range (the temperatures of the reaction with CO2) is preferably from 950 °C to 1100 °C in order to eliminate disturbing influences, such as the influence of the pore structure.

[0037] From the point of view of reactivity with CO2, the predetermined time is preferably 10 minutes or more. From the point of view Petition 870250088713, dated 09 / 30 / 2025, page 17 / 36 11 / 18 of the reduction in measurement time, the predetermined time is preferably 120 minutes or less. As already described, the predetermined time is a residence time in the atmosphere of CO2 within the predetermined temperature range.

[0038] After individual coal coke has been held in a CO2 atmosphere within a predetermined temperature range for a predetermined time, as described above, the percentage of weight loss (the TG reactivity index of the individual coal coke) is measured. Step for estimating the TG reactivity index of coal-mixed coke.

[0039] The TG reactivity indices of individual coal cokes measured by TG have additivity. Therefore, it is possible to estimate the TG reactivity index of the coal coke mixture from the weighted average of the TG reactivity indices of the individual coal cokes multiplied by the mixing proportions of the individual coals that constitute the coal mixture. In other words, the TG reactivity index of the coal coke mixture after being held in a CO2 atmosphere within a predetermined temperature range for a predetermined time can be estimated from the measured TG reactivity indices of the individual coal cokes.

[0040] Figure 1 represents the weighted average of the measured TG reactivity indices of the individual coal cokes on the horizontal axis and the measured TG reactivity index of the corresponding coal coke mixture on the vertical axis. As illustrated in Figure 1, there is a correlation between the weighted average of the measured TG reactivity indices of the individual coal cokes and the measured TG reactivity index of the corresponding coal coke mixture. In other words, the results Petition 870250088713, dated 09 / 30 / 2025, page 18 / 36 Figures 12 / 18 show that the TG reactivity index of coal blended coke after blending can be estimated based on the TG reactivity indices of the individual coal cokes. This step uses this correlation to estimate the TG reactivity index of coal blended coke from the weighted average of the actually measured TG reactivity indices of the individual coal cokes. Stage of estimating the coke reactivity index (CRI) of coal-mixed coke.

[0041] In this step, the coke reactivity index (CRI) of the coal-mixed coke is estimated from the coal-mixed coke reactivity index (TG) estimated in the previous step. Figure 2 illustrates the relationships between the estimated coal-mixed coke reactivity index (TG) and the actually measured coal-mixed coke reactivity index (CRI). As illustrated in Figure 2, there is a correlation between the estimated coal-mixed coke reactivity index (TG) and the actually measured coal-mixed coke reactivity index (CRI). This correlation can provide an expression in advance for estimating the coal-mixed coke reactivity index (CRI) (expression (1) described later). The coal-mixed coke reactivity index (CRI) can thus be estimated from the estimated coal-mixed coke reactivity index (TG).

[0042] Next, a process for estimating the coke strength of coal-mixed coke after reaction with CO2 (CSR) from the estimated coke reactivity index (CRI) of the coal-mixed coke and the drum index (DI) of the coal-mixed coke will be described. In the present embodiment, the drum index (DI) of the coal-mixed coke is the DI15015 specified in JIS K 2151: 2004. However, the drum index (DI) of the coal-mixed coke Petition 870250088713, dated 09 / 30 / 2025, page 19 / 36 13 / 18 of coal is not limited to the same and may be, for example, a value obtained from a known estimation expression. Figure 3 illustrates the relationship between coke resistance after reaction with CO2 (CSR) and the coke reactivity index (CRI) for various coke drum indices (DI15015), representing actually measured values ​​of the coke reactivity index (CRI) on the horizontal axis and actually measured values ​​of coke resistance after reaction with CO2 (CSR) on the vertical axis. Figure 3 shows that there is a strong correlation between coke resistance after reaction with CO2 (CSR) and the coke reactivity index (CRI) and also shows that the variation in coke resistance after reaction with CO2 (CSR) at the same coke reactivity index (CRI) is affected by the coke drum index (DI). Using this relationship, it is possible to estimate the resistance of coke after reaction with CO2 (CSR) from the coke reactivity index (CRI) and the coke drum index (DI).In this embodiment, the coke strength of coal-mixed coke after reaction with CO2 (CSR) can be easily estimated using the coke reactivity index (CRI) of the coal-mixed coke estimated through the process described above.

[0043] In the present invention, TG measurement of the reactivity of individual coal cokes to be mixed allows estimation of the coke strength after reaction with CO2 (CSR) that will be obtained when the individual coals are mixed and carbonized in the corresponding coal coke mixture. Thus, the present invention allows a rapid estimation of the coke strength of the coal coke mixture after reaction with CO2 (CSR).

[0044] The method for estimating the CSR of coal-mixed coke of the present invention allows the production of coke in such a way that the proportions of coal mixtures (individual coals) are controlled by estimating the strength of the coke after reaction with CO2. Petition 870250088713, dated 09 / 30 / 2025, page 20 / 36 14 / 18 (CSR) which will be obtained when individual coals are mixed and carbonized into the corresponding coal blend coke. Thus, a coal blend coke with stable CSR quality can be produced. Furthermore, the ability to produce coal blend coke while estimating the coke strength of the coal blend coke after reaction with CO2 (CSR) can reduce variations in CSR. Thus, for example, it becomes possible to design the blend closer to the lower limit of the target CSR range than was previously possible, expand the variety of feedstock grades that can be used, and reduce the production costs of coal blend coke.

[0045] A method for producing coal blend coke of the present invention uses the method for estimating the CSR of coal blend coke described above. Specifically, the strength of the coal blend coke after reaction with CO2 is estimated using the method for estimating the CSR of coal blend coke above, and the production conditions are altered based on the estimated strength of the coal blend coke after reaction with CO2. More specifically, the production conditions can be altered so that the estimated strength of the coal blend coke after reaction with CO2 reaches a target coke strength. For example, the production conditions include the mixing ratios (mixing percentages) of the coals (individual coals).

[0046] A method of operating a coke oven according to the present invention uses the method for estimating the CSR of coal-mixed coke described above. Specifically, the coke strength of coal-mixed coke after reaction with CO2 is estimated using the method for estimating the CSR of coal-mixed coke above and the operating conditions of the coke oven are Petition 870250088713, dated 09 / 30 / 2025, page 21 / 36 15 / 18 altered based on the estimated strength of the coke from the coal-coke mixture after reaction with CO2. More specifically, the operating conditions of the coke oven can be altered so that the estimated strength of the coke from the coal-coke mixture after reaction with CO2 reaches a target coke strength. For example, operating conditions include the coal mixing ratios (individual coals).

[0047] A method for controlling the mixing ratios of individual coals according to the present invention uses the method for estimating the CSR of the coal-mixed coke described above. Specifically, the coke strength of the coal-mixed coke after reaction with CO2 is estimated using the method for estimating the CSR of the coal-mixed coke above, and the mixing ratios of individual coals are altered based on the estimated strength of the coal-mixed coke after reaction with CO2. More specifically, the mixing ratios of individual coals can be altered so that the estimated strength of the coke of the coal-mixed coke after reaction with CO2 reaches a target coke strength.

[0048] The method for producing a coal-mixed coke, the method of operating a coke oven, and the method for controlling the mixing ratios of individual coals according to the present invention can achieve the same effects described above by virtue of using the method for estimating the CSR of the coal-mixed coke of the present invention. EXAMPLES

[0049] The present invention will now be described by way of example. However, the present invention is not limited to the following examples.

[0050] Coal mixture coke ready to be loaded Petition 870250088713, dated 09 / 30 / 2025, p. 22 / 36 16 / 18 of the coal-mixed coke samples in a real furnace were measured for the coke strength of the coal-mixed coke after reaction with CO2 (CSR) and the coke reactivity index (CRI) of the coal-mixed coke according to ISO 18894, and also measured for the drum index (DI150is) of the coal-mixed coke according to JIS K 2151: 2004. The individual coals used in this coke production were tested according to JIS M 8812: 2006 to measure volatile matter (VM), and the resulting carbides (cokes from individual coals) were sampled. Each of the individual coal coke samples was pulverized to 850 μm or less, and sample splitting was performed. The particles were then sieved through a 200 μm sieve. The grain size was then controlled to 850 μm to 200 μm.

[0051] The TG reactivity index of individual coal coke was measured using a LINSEIS STA1600 TG device. The sample weight was 0.5 g. In a N2 atmosphere, the sample was heated to 950 °C at 100 °C / min and maintained for 20 minutes until the atmosphere temperature stabilized. Subsequently, the gas was changed from N2 to CO2. The CO2 gas feed rate was set to 1000 mL / min and the sample was maintained (reacted) in a CO2 atmosphere for 60 minutes. The percentage of weight loss [%] was measured according to [(weight before reaction - weight after reaction) / (weight before reaction)] χ 100. The weighted average of the percentage of weight loss (the TG reactivity indices) of the individual coal cokes multiplied by the mixing ratios of the individual coal cokes was calculated to estimate the TG reactivity index of the coal coke mixture.

[0052] Next, the correlation illustrated in Figure 2 between the estimated TG reactivity index of the coal blend coke and the actually measured coke reactivity index (CRI) of the blend coke is shown. Petition 870250088713, dated 09 / 30 / 2025, page 23 / 36 17 / 18 of coal was studied and expression (1) described below was established for estimating the coke reactivity index (CRI) of coal-mixed coke. Coke reactivity index (CRI) of coal-mixed coke = ax (reactivity index TG of coal-mixed coke) + b ··· (1)

[0053] Here, a and b in expression (1) are constants. In this example, a = 0.55 and b = 20. The TG reactivity index of the coal-mixed coke estimated above was substituted into expression (1) to determine the coke reactivity index (CRI) of the coal-mixed coke.

[0054] The relationship between coke resistance after reaction with CO2 (CSR) and the coke reactivity index (CRI) according to ISO 18894 for various coke drum indices (DI, DI15015 in this Example) are illustrated in Figure 3. From the relationships, expression (2) described below was established as the regression expression to estimate coke resistance after reaction with CO2 (CSR).

[0055] Resistance of coke after reaction with CO2 (CSR) = cx (coke reactivity index (CRI)) + dx (DI15015 of coke) + e ··· (2)

[0056] Here, c, d, and e are constants. In this example, c = -1.4, d = 0.91, and e = 24. The coke reactivity index (CRI) of the coal-mixed coke determined by expression (1) and the actually measured drum index (DI15015) of the coal-mixed coke were substituted into expression (2) to determine the coke strength of the coal-mixed coke after reaction with CO2 (CSR). The ratio between the thus estimated coke strength of the coal-mixed coke after reaction with CO2 (CSR) and the actually measured coke strength of the coal-mixed coke after reaction with Petition 870250088713, dated 09 / 30 / 2025, page 24 / 36 18 / 18 CO2 (CSR) is illustrated in Figure 4. As illustrated in Figure 4, the method for estimating the CSR of coal blended coke of the present invention, based on the TG reactivity indices of the individual coal cokes measured by TG, can estimate the coke strength of the corresponding coal blended coke after reaction with CO2 (CSR). Petition 870250088713, dated 09 / 30 / 2025, page 25 / 36

Claims

1 / 2 CLAIMS 1. Method for estimating the CSR of coal blend coke, for estimating the coke strength of a coal blend coke after reaction with CO2 (CSR) using a reactivity index TG which is a percentage of the weight loss measured by thermogravimetry of the coke held in a CO2 atmosphere within a predetermined temperature range for a predetermined time, characterized in that it comprises: a step of measuring the reactivity indices TG of individual coal cokes and estimating the reactivity index TG of the corresponding coal blend coke from the weighted average of the measured reactivity indices TG of the individual coal cokes; a step of estimating a coke reactivity index (CRI) of the coal blend coke from the TG reactivity index of the coal blend coke estimated in the previous step;and a step to estimate the coke strength of the coal-mixed coke after reaction with CO2 (CSR) from the coke reactivity index (CRI) of the coal-mixed coke estimated in the previous step and a drum index (DI) of the coal-mixed coke.

2. Method for estimating the CSR of coal-mixed coke, according to claim 1, characterized in that thermogravimetry is performed by heating the coke in an inert gas atmosphere in a temperature range of 950 °C to 1100 °C.

3. Method for estimating the CSR of coal-mixed coke, according to claim 1, characterized in that the predetermined time is 10 minutes or more and 120 minutes or less.

4. Method for estimating the CSR of coke from a mixture of coal Petition 870250088713, dated 09 / 30 / 2025, page 26 / 36 2 / 2, according to claim 2, characterized in that the predetermined time is 10 minutes or more and 120 minutes or less.

5. A method for producing a coal blend coke, characterized in that it comprises: estimating the coke strength of the coal blend coke after reaction with CO2 using the method for estimating the CSR of the coal blend coke as defined in any one of claims 1 to 4; and altering a production condition based on the estimated coke strength of the coal blend coke after reaction with CO2.

6. A method for operating a coke oven, characterized in that it comprises: estimating the coke strength of the coal-mixed coke after reaction with CO2 using the method for estimating the CSR of the coal-mixed coke as defined in any one of claims 1 to 4; and altering an operating condition of a coke oven based on the estimated strength of the coke, of the coal-mixed coke after reaction with CO2.

7. Method for controlling the mixing ratios of individual coals characterized in that it comprises: estimating the coke strength of the coke-coal mixture after reaction with CO2 using the method for estimating the CSR of the coke-coal mixture, as defined in any one of claims 1 to 4; and altering the mixing ratios of individual coals based on the estimated coke strength of the coke-coal mixture after reaction with CO2. Petition 870250088713, dated 09 / 30 / 2025, pp. 27 / 36

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