Method for predicting the calorie content of coke oven gas

Abstract

To provide a method for predicting gas calorie of a coke-oven gas that can accurately estimate the gas calorie of the coke-oven gas communicated in a steel mill in real time without actually measuring the gas calorie of the coke-oven gas for each kiln.SOLUTION: A method 10 for predicting the gas calorie of the coke-oven gas generated in a process of carbonizing coal in a coke-oven to produce coke includes: cumulative coal charge amount calculation step S1 for integrating a coal charge amount into a carbonization chamber of the coke-oven within a cumulative time from a predicted point in time to 30% to 70% of the carbonization time of the coal; and gas calorie prediction step S2 for predicting the gas calorie of the coke-oven gas at the predicted point in time by using the cumulative coal charge amount calculated in the cumulative coal charge amount calculation step and a conversion factor that can convert the cumulative coal charge amount into the gas calorie.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a method for predicting the gas calorie of coke oven gas. [Background technology]

[0002] Coke oven gas (COG) generated during the carbonization of coal to produce coke is used as fuel in steelworks. However, fluctuations in the operation of the coke ovens, which are the source of COG, can result in a decrease in the amount of coke oven gas generated (COG amount) and the gas calories of the coke oven gas (COG calories). A decrease in COG amount and COG calories can lead to reduced production and shutdowns due to reduced operating rates of heating furnaces and burners at each factory that uses COG, as well as quality problems in direct reduction furnaces and other facilities due to reduced heat output. Therefore, if a decrease in COG amount and COG calories can be predicted, these problems can be prevented by taking advance measures.

[0003] As described in Patent Document 1, the amount of COG generated can be calculated and estimated from the amount of coal charged, the volatile matter content of the coal, the storage time, and the carbonization time, and it is not difficult to predict the amount of COG generated if the operational fluctuations themselves can be understood. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-1981 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, even if operational fluctuations can be grasped, there are the following issues with real-time prediction of generated COG calories.

[0006] When COG is used industrially, its calorific value is lower than that calculated from its theoretical composition (e.g., JP 2011-148924 A, etc.). This is thought to be due to the dilution of gases generated from coal by the intrusion of outside air into the coke oven and COG piping system, and by the intrusion of exhaust gases generated by the combustion of H2 generated at the end of carbonization with O2 in the atmosphere. The resulting difference in COG calories (the difference between the theoretical value and the actual calorific value) is not significant in a healthy coke oven. However, as a coke oven ages, the integrity of the furnace body deteriorates and operational fluctuations increase, resulting in a significant decrease in the amount of COG generated and the COG calories. This difference can become significant and could cause problems in the industrial use of COG.

[0007] Furthermore, because the amount of outside air entering each coke oven differs, in order to know the COG calorie value, it is necessary to measure the calorie content of each coke oven. However, determining the calorie content of each oven is difficult in practice due to issues such as cost and effort.

[0008] In view of the above-mentioned circumstances, the present invention aims to provide a method for predicting the gas calories of coke oven gas, which can accurately estimate the gas calories of coke oven gas circulating within a steelworks in real time, without actually measuring the gas calories of coke oven gas for each kiln (each carbonization chamber). [Means for solving the problem]

[0009] As a result of intensive research into the above-mentioned problem, the present inventors have found that the gas calories of coke oven gas can be accurately estimated by multiplying the total amount of coal charged within a predetermined cumulative time by a predetermined conversion coefficient. The present invention has been completed based on this finding.

[0010] One aspect of the present invention for solving the above problem is a method for predicting the gas calories of coke oven gas generated in the process of carbonizing coal in a coke oven to produce coke, the method comprising: an accumulated coal amount calculation step for accumulating the amount of coal charged into the carbonization chamber of the coke oven within an accumulated time that is 30% to 70% of the time from the time of prediction until the time before the carbonization of the coal; and a gas calorie prediction step for predicting the gas calories of the coke oven gas at the time of prediction using the accumulated coal amount calculated in the accumulated coal amount calculation step and a conversion coefficient that can convert the accumulated coal amount into gas calories, wherein the conversion coefficient is calculated based on past gas calorie results.

[0011] In the cumulative coal charge amount calculation step of the gas calorie prediction method, the cumulative time is preferably from the prediction time to 40% to 60% of the coal carbonization time. Furthermore, the conversion coefficient is preferably calculated based on past gas calorie records from the relationship between the past cumulative coal charge amount, which is accumulated over the same period as the cumulative time, and the past actual gas calorie value of the coke oven gas, and more preferably from the relationship between the past cumulative coal charge amount and the past actual gas calorie value using the same coal type as the coal used in the gas calorie prediction method. Furthermore, the gas calorie prediction method preferably further includes a step of repeatedly performing the cumulative coal charge amount calculation step and the gas calorie prediction step based on a coke oven operation schedule to obtain the relationship between the operation schedule and the predicted gas calorie value. [Effects of the Invention]

[0012] According to the present invention, the gas calories of the coke oven gas circulating within a steelworks can be estimated accurately in real time without actually measuring the gas calories of the coke oven gas for each furnace. [Brief explanation of the drawings]

[0013] [Figure 1] This is a schematic diagram of the COG system of a coke oven. [Figure 2] This is a schematic diagram of the COG system of a deteriorated coke oven. [Figure 3] 1 is a flowchart of a method 10 for predicting gas calorie of coke oven gas. [Figure 4] FIG. 10 is a diagram illustrating differences in conversion factors for each coal type. [Figure 5] This is a specific example of a method 10 for predicting the gas calorie of coke oven gas. (a) is a diagram showing the amount of coal charged into a coke oven by time, (b) is a diagram showing the cumulative amount of coal charged by time, and (c) is a diagram (prediction chart) in which the cumulative amount of coal charged in (b) is multiplied by a conversion factor and converted into COG calories. [Figure 6] FIG. 10 is a diagram showing time trends of predicted COG calorie values ​​and actual COG calorie values ​​for each cumulative time period. [Figure 7] FIG. 10 is a diagram showing the error (COG calorie error) between the predicted COG calorie value and the actual COG calorie value for each integrated time period. [Figure 8] These are the results of field tests. [Figure 9] FIG. 10 is a diagram for explaining the accuracy of COG calorie prediction when the cumulative time is set to 11 hours or 24 hours in a field test. DETAILED DESCRIPTION OF THE INVENTION

[0014] 1.Preliminary Consideration The coke oven to which the present invention can be applied is a chamber-hearth coke oven. A chamber-hearth coke oven is a brick structure with a regenerator at the bottom of the furnace body and combustion chambers and carbonization chambers arranged alternately at the top. The carbonization chamber is surrounded by bricks, and coal is charged through a charging port on the top. The combustion chamber is adjacent to the carbonization chamber via a furnace wall (brick wall) and is divided into 20 to 30 flues along the furnace length. The bottom of each flue is connected to the regenerator, and preheated combustion gas is supplied to the flue. The fuel gas burns there, heating the carbonization chambers on both sides and promoting carbonization of the coal. The produced coke is extruded by an extruder from the rear of the furnace (the extruder side) and removed from the front of the furnace (the coke discharge side). The configuration of this coke oven is the same as that of a typical chamber-hearth coke oven.

[0015] As described above, coal is carbonized in the carbonization chamber, and during this process, a large amount of COG is generated from the coal along with tar. Each carbonization chamber is equipped with piping leading to a gas purification facility, so the tar and COG generated in the carbonization chamber are separated and collected, and sent to the gas purification facility via piping. The COG is then refined in the gas purification facility and sent to various plants, etc. Here, the COG calories are measured after being refined in the gas purification facility and before being sent to various plants, etc. Specifically, they are measured using a calorimeter (QT) attached to the piping connecting the gas purification facility to various plants, etc. Figure 1 shows a schematic diagram of the carbonization chamber, gas purification facility, and piping that sends the COG (COG system schematic diagram).

[0016] On the other hand, as the coke oven deteriorates, fluctuations in its operation increase, resulting in a significant decrease in COG calories. For example, the reasons why COG calories decrease as the coke oven deteriorates are as follows:

[0017] (1) Carbonization chamber furnace lid The coke chamber is usually isolated from the outside air by furnace covers installed at both ends of the furnace length. However, if the coke oven deteriorates and the furnace body deforms, the lids may not be able to close properly. Because the pressure inside the coke chamber is usually positive, generated gases flow out of the system. However, as the carbonization time increases and the carbonization process nears its end, negative pressure tends to occur in certain areas of the furnace. If the lid is not closed properly, outside air will enter the coke chamber. This will increase the amount of N2 and O2, which are components of the outside air, in the COG, and furthermore, the composition of the COG will change due to the reaction between the O2 and the combustion components in the COG. This dilutes the COG and reduces its calorie content.

[0018] (2) The brick joints separating the coking chamber and the combustion chamber Joints are the gaps between stacked bricks, and filler is applied to the joints in the walls of a coke oven. The applied filler is sometimes simply called the joint. As the coke oven deteriorates, cracks appear in these joints, leaving part of the coking chamber and the combustion chamber connected. This is called a joint break. The coking chamber is normally maintained at a positive pressure by the generated gas, so if a joint break occurs, the gas inside the coking chamber will leak into the combustion chamber. Furthermore, coke ovens periodically switch between combustion and exhaust, and the pressure in the combustion chamber may temporarily drop during this switching. Therefore, if a joint break occurs, the pressure in the coking chamber will also temporarily drop along with the drop in the combustion chamber pressure. In such cases, air that has entered the coking chamber through gaps in the oven cover may react with and burn COG, or conversely, exhaust gas may flow from the combustion chamber into the coking chamber, increasing the N2 content of the COG and reducing the COG calories.

[0019] (3) The existence of idle coke oven chambers and unevenness in the amount of coal charged (the amount of coal charged into the coke oven chambers) Figure 2 shows a schematic diagram of the COG system of a deteriorated coke oven. As shown in Figure 2, as a coke oven deteriorates, the amount of coal charged (the amount of coal charged into the coke oven) in some coke ovens (coke ovens #2 and #i in Figure 2) is reduced to reduce the load on the equipment, and some coke ovens are not in operation due to repairs or other reasons (coke oven #i+1 in Figure 2). As a result, the distribution of elapsed carbonization time for multiple coke ovens producing coke at a given time point and for the coal being carbonized becomes uneven. As will be described later, if there are many coke ovens in the early stages of carbonization, the COG calories will be high, and if there are many coke ovens in the late stages of carbonization, the COG calories will be low. As such, as a coke oven deteriorates, the amount of coal charged in each coke oven chamber tends to vary, which can lead to large fluctuations in COG calories and a decrease in COG calories. In such cases, measures such as supplying combustible gas such as natural gas from point A in Figure 2, measuring the COG calories and the COG calories with combustible gas added using calorimeters before and after the supply point, and adjusting the COG calories to an appropriate level before sending the COG to the factory, etc., are taken, but the addition of combustible gas increases operating costs.

[0020] For the above reasons, COG calories fluctuate and decrease as the coke oven deteriorates, so prediction of this is extremely important for industrial use of COG.

[0021] Therefore, the present inventors have investigated a method for accurately predicting COG calories. First, because COG generation is caused by coal during carbonization, the present inventors have investigated the relationship between COG calories and the total amount of coal charged during carbonization. As a result, they have found that the accuracy of COG calorie prediction is low.

[0022] Next, the inventors focused on the fact that the composition of COG is not constant during coal carbonization. It is known that the COG calorific value is not constant during coal carbonization but changes depending on the elapsed time of carbonization (see the Iron and Steel Handbook). A typical progression is that CH4 is abundant and the calorific value is high in the early stages of carbonization, reaching a maximum value midway through the carbonization time, and then the calorific value gradually decreases toward the end of the carbonization due to increased H2 generation. Specifically, when the carbonization time is 24 hours, the amount of CH4 generated is large and the calorific value remains high from the beginning of coal loading until about 11 hours have passed, but after 11 hours, the gas calories begin to decrease due to an increase in the H2 concentration in the gas.

[0023] In normal coke oven operation, COG is purified by collecting gases generated from several dozen or even 100 or more coking chambers. The operation schedules of these coking chambers are standardized so that coal charging and coke extrusion operations are not concentrated in specific time periods. Therefore, even if the calorific value of gas generated from an individual coking chamber changes over the elapsed time of carbonization, the calorific value of COG from the entire coke oven does not usually change significantly.

[0024] The inventors of the present invention investigated the relationship between the total amount of coal charged and COG calories for coal that generates a large amount of CH4 (coal charged within 11 hours of coal loading), because the calorific value in the early stage of carbonization is stable at a high level. As a result, it was found that the prediction accuracy of COG calories is very high. The present invention was completed based on this finding.

[0025] 2. Method for predicting the gas calorie content of coke oven gas Hereinafter, the method for predicting gas calories of coke oven gas according to the present invention will be described using a method 10 for predicting gas calories of coke oven gas (hereinafter, sometimes referred to as "prediction method 10"), which is one embodiment.

[0026] [Method 10 for predicting the gas calorie content of coke oven gas] A coke oven gas calorie prediction method 10 is a method for predicting the gas calories of coke oven gas generated during the process of carbonizing coal in a coke oven to produce coke. The method includes: an accumulated coal charge amount calculation step S1, which calculates the amount of coal charged into the coke oven chamber during an accumulated time from the time of prediction to 30% to 70% of the time before the coal carbonization time; a gas calorie prediction step S2, which predicts the gas calories (COG calories) of the coke oven gas at the time of prediction using the accumulated coal charge calculated in the accumulated coal charge amount calculation step S1 and a conversion coefficient for converting the accumulated coal charge amount to gas calories; and a step S3 (hereinafter sometimes referred to as a "prediction chart creation step S3"), which repeatedly performs the accumulated coal charge amount calculation step S1 and the gas calorie prediction step S2 based on the coke oven operation schedule to obtain a relationship between the operation schedule and the predicted gas calorie values. A flowchart of the prediction method 10 is shown in FIG. 3.

[0027] <Accumulated coal amount calculation process S1> The cumulative coal amount calculation step S1 is a step of calculating the cumulative time from the prediction point to 30% to 70% of the coal carbonization time, and accumulating the amount of coal charged into the coke chamber of the coke oven within this cumulative time.

[0028] The "prediction time" refers to the time at which COG calories are predicted. This may be the current time, a past time, or a future time. By appropriately setting the prediction time, real-time prediction becomes possible. "Coal carbonization time" is the time set for completing the carbonization of coal. In principle, the carbonization time of coal in each coking chamber belonging to the same operating furnace battery is basically the same.

[0029] The accumulated time is preferably 40% to 60% of the time until the carbonization time of the coal from the time of prediction, and more preferably 40% to 50% of the time until the carbonization time of the coal from the time of prediction, which improves the accuracy of the prediction of COG calories.

[0030] For example, when the dry distillation time is set to about 24 hours, the specific cumulative time is 8 to 16 hours, preferably 10 to 14 hours, and more preferably 10 to 12 hours.

[0031] <Gas calorie prediction process S2> The gas calorie prediction step S2 is a step of predicting COG calories at the time of the prediction using the cumulative coal amount calculated in the cumulative coal amount calculation step S1 and a conversion coefficient capable of converting the cumulative coal amount into gas calories. That is, the gas calorie prediction step S2 is a step of multiplying the cumulative coal amount by the conversion coefficient. The conversion coefficient indicates the COG calories per unit cumulative coal amount.

[0032] The conversion coefficient is calculated based on the past actual gas calorie data. Specifically, the conversion coefficient is calculated based on the past actual gas calorie data from the relationship between the past accumulated coal amount accumulated over the same accumulated time period as that used in the accumulated coal amount calculation step S1 and the past actual gas calorie value of the coke oven gas.

[0033] "Past gas calorie results" includes past actual COG calorie values ​​and past coke oven operation information. "Past cumulative coal loading amount accumulated over the same cumulative time as used in cumulative coal loading amount calculation step S1" is the total amount of coal loaded into the coke oven coke chamber from the time when the past actual COG calorie values ​​were measured until the same cumulative time as used in cumulative coal loading amount calculation step S1. "Relationship between the past cumulative coal loading amount accumulated over the same cumulative time as used in cumulative coal loading amount calculation step S1 and the past actual gas calorie values ​​of coke oven gas" is the relationship between the above-mentioned past cumulative coal loading amount and the past actual COG calorie values. "Calculated from the relationship ..." means, for example, calculating a conversion coefficient by performing sequential calculations using the relationship.

[0034] Preferably, the conversion coefficient is calculated from the relationship between the cumulative coal loading amount in the past and the actual gas calorie results in the past, using the same coal type as that used in the gas calorie prediction method. "The same coal type" means the same brand of coal when a single brand of coal is used, and when a combination of multiple brands of coal is used, it means the same combination of brands of coal. Because coal is a natural product, the same brand does not necessarily mean that the coal has exactly the same properties, but when the brand is the same, the coal properties (elemental composition, indicators of how easily it can be made into coke, COG calories, etc.) are nearly constant. Therefore, calculating the conversion factor from past gas calorie results using the same coal type improves the accuracy of COG calorie predictions.

[0035] The calculation method of the conversion factor will be further explained using Figure 4. Figure 4 shows the cumulative coal loading amount on the horizontal axis and the actual COG calorie values ​​on the vertical axis, with the small and large dots representing different coal types. Using this graph, sequential calculations are performed to calculate the correlation (slope) between the cumulative coal loading amount and the actual COG calorie values, and this correlation (slope) is used as the conversion factor. As shown in Figure 4, comparing the slope of the straight line calculated from the small dots with the dashed line calculated from the large dots reveals that the slope differs for each coal type. Because the relationship between the cumulative coal loading amount and COG calories differs for each coal type, prediction accuracy can be improved by using a conversion factor calculated using the same coal type as the coal type used for gas calorie prediction.

[0036] <Prediction chart creation process S3> The forecast chart creation step S3 is a step of repeatedly performing the cumulative coal loading amount calculation step S1 and the gas calorie prediction step S2 based on the coke oven operation schedule to obtain the relationship between the operation schedule and the predicted gas calorie value. Specifically, this step is a step of repeatedly performing the cumulative coal loading amount calculation step S1 and the gas calorie prediction step S2 while changing the COG calorie prediction time based on the coke oven operation information to obtain the relationship between the operation schedule and the predicted gas calorie value. The coke oven operation information includes information such as the amount of coal loaded per coke oven chamber, the timing of coal loading, the coal carbonization time, and which coke oven chambers are in operation and which are out of operation. Using this information, step S3 is performed to create a forecast chart, for example, with time on the horizontal axis and predicted gas calorie value on the vertical axis. The created forecast chart is output, for example, to a display so that it can be perceived by relevant parties such as coke oven operators, production planning departments, and energy departments.

[0037] <Example> Next, prediction method 10 will be specifically explained using Fig. 5. Fig. 5(a) is a diagram showing the amount of coal charged into a coke oven by time, Fig. 5(b) is a diagram showing the cumulative amount of coal charged by time, and Fig. 5(c) is a diagram in which the cumulative amount of coal charged in Fig. 5(b) is multiplied by a conversion factor and converted into COG calories.

[0038] First, the prediction time point in the cumulative coal loading amount calculation step S1 is set to point B in Figure 5(a). The cumulative time is set to the period indicated by the arrow in Figure 5(a). Using these conditions, all coal loading amounts within the cumulative time are added together to calculate the total cumulative coal loading amount. This is shown as point B in Figure 5(b). Next, in the gas calorie prediction step S2, a conversion coefficient calculated based on past gas calorie results is used to calculate the predicted COG calorie value at point B (Figure 5(c)). These steps are then repeated based on the operation schedule to obtain the relationship between the operation schedule and predicted gas calorie values ​​(prediction chart) as shown in Figure 5(c).

[0039] The method for predicting gas calories of coke oven gas according to the present invention has been described above using the method 10 for predicting gas calories of coke oven gas.

[0040] Conventionally, theoretical values ​​of COG calories can be calculated from coal components (e.g., JP 2011-148924 A), and predictions have been made using these values, but predictions using theoretical values ​​have not been able to predict time fluctuations. On the other hand, the present invention can predict COG calories based on an operation schedule, making it possible to predict time fluctuations with high accuracy (real-time prediction).

[0041] Therefore, by using the present invention, COG calories can be predicted over the long term, which makes it possible to accurately determine whether to operate each plant in a steelworks or postpone regular maintenance, for example, when a significant drop in COG calories occurs. Furthermore, when performing processes where a drop in COG calories directly affects steel sheet quality, such as a direct reduction furnace, it becomes possible to prepare in advance for the need to increase heat by mixing external energy such as combustible gases, thereby improving the stability of steelworks production activities. Furthermore, even if irregular operating conditions occur due to unforeseen circumstances, the present invention allows for easy correction of the prediction line through sequential calculations, providing ample time to take countermeasures. This prevents quality defects and production reductions at plants that use COG and improves the accuracy of COG balance predictions used to determine the timing of plant maintenance, etc. [Example]

[0042] The present invention will now be further described with reference to examples.

[0043] <Consideration of integration time> Using the gas calorie prediction method for coke oven gas explained above, the predicted COG calorie values ​​obtained by changing the cumulative time were compared with the measured COG calorie values. In the test, the carbonization time was set to 24 hours, and the cumulative time was set to 8 hours, 11 hours, 12 hours, and 16 hours. The ratio of the cumulative time to the carbonization time was 3. 3 %, 46%, 50%, 6 7 The results are shown in Figures 6 and 7.

[0044] Figure 6 shows the predicted COG calorie values ​​calculated by varying the cumulative time and the actual COG calorie values, superimposed and arranged in chronological order. Figure 7 shows the maximum difference (maximum error) between the predicted COG calorie values ​​and the actual COG calorie values ​​for each cumulative time.

[0045] From Figures 6 and 7, it can be seen that the maximum error is approximately 100 kcal / Nm 3When the cumulative time is set to 24 hours, the same as the carbonization time, the maximum error is about 100 kcal / Nm 3 This is because it is difficult to keep the maximum error to a level close to that. Furthermore, when the cumulative time was set to 8, 11, and 12 hours, the maximum error was further reduced, and when it was set to 11 hours, the maximum error was further reduced. Furthermore, from FIG. 7, it is considered that these maximum errors have a quadratic correlation. Taking these results and correlations into consideration, it is considered that the cumulative time should be set to 30% to 70% of the carbonization time, preferably 40% to 60%, and more preferably 40% to 50%.

[0046] <Field Test> A field test was conducted using the gas calorie prediction method for coke oven gas described above. The cumulative time for this test was set to 11 hours. The results are shown in Figure 8.

[0047] As shown in FIG. 8, the predicted COG calorie values ​​and actual COG calorie values ​​generally match, and it can be said that the COG calories were predicted with high accuracy. Furthermore, on the third day of the test period, maintenance work on the coke oven was planned, and there were concerns about a decrease in COG calories, but this was also predicted with good accuracy. Also, on the third day, the actual COG calories were the lowest during the test period (3864 kcal / Nm 3 ), while the predicted COG calorie value was also the lowest (3788kcal / Nm 3 ) was calculated. This difference was 58kcal / Nm 3 and were very close values. Furthermore, during the test period, the difference between the predicted COG calorie value and the actual COG calorie value was ±100 kcal / Nm 3 When the percentage within this range was calculated, the percentage was 72.9%, which was an extremely high value. This also shows that the method for predicting gas calories of coke oven gas of the present invention can predict COG calories with high accuracy.

[0048] On the other hand, when prediction is made by setting the cumulative time to 24 hours, which is the same as the carbonization time, prediction accuracy is not as high as that of the present invention. Figure 9 shows the distribution of predicted COG calories when the cumulative time is set to 24 hours during the above test period. For comparison, the distribution of predicted COG calories when the cumulative time is set to 11 hours is also shown. Figure 9 shows that when the cumulative time is set to 24 hours, the difference between the predicted COG calories and the actual COG calories is ±100 kcal / Nm 3 The percentage within this range was 18.3%, which was a very low value.

Claims

1. Coke oven gas generated in the process of carbonizing coal to produce coke in a coke oven having multiple carbonization chambers. A gas calorie prediction method, comprising: The accumulated time is from the prediction point to 30% to 70% of the carbonization time of the coal, and an accumulated coal amount calculation step of accumulating the amount of coal charged into the coke chamber of the coke oven within a calculated time; 、 The cumulative coal amount calculated in the cumulative coal amount calculation step and the cumulative coal amount calculated by the gas calorie calculation step The gas calorie of the coke oven gas at the time of the prediction is calculated using a conversion factor that can be converted into and a gas calorie prediction step of predicting the amount of gas consumed. The conversion factor is calculated based on past gas calorie performance. A method for predicting the gas calorie content of coke oven gas.

2. In the cumulative coal amount calculation step, the cumulative time is calculated from the prediction time to the time of carbonization of the coal. The gas calorie prediction method according to claim 1, wherein the time is 40% to 60% of the time before the end of the period.

3. The conversion factor is calculated based on the past gas calorie results and is calculated over the same period as the cumulative time. The calculation is based on the relationship between the cumulative coal amount and the actual gas calorie value of coke oven gas. The gas calorie prediction method according to claim 1 or 2,

4. The conversion coefficient is a value obtained by using the same coal type as the coal used in the gas calorie prediction method. The method according to claim 3, wherein the method is calculated from the relationship between the cumulative coal loading amount in the past and the actual gas calorie amount in the past. The gas calorie prediction method described.

5. The cumulative coal amount calculation step and the gas calculation step are carried out based on the operation schedule of the coke oven. The calorie prediction step is repeated to determine the relationship between the operation schedule and the predicted gas calorie value. The gas calorie prediction method according to any one of claims 1 to 4, further comprising the step of obtaining:

Images