Method for estimating supplied heat, device for estimating supplied heat, computer-readable recording medium recording supplied heat estimation program, and method for operating blast furnace

Abstract

The present application provides a supply heat amount estimation method for estimating a heat amount supplied to molten pig iron in a blast furnace, based on a heat amount supplied to the blast furnace and a production rate of the molten pig iron in the blast furnace, the method including: an estimation step of estimating a change in outgoing sensible heat caused by a gas in the blast furnace and a change in incoming sensible heat supplied from a raw material preheated by the gas in the blast furnace, estimating the heat amount supplied to the molten pig iron in the blast furnace, taking into account the changes in the outgoing sensible heat and the incoming sensible heat, the estimation step including: a step of estimating the changes in the outgoing sensible heat and the incoming sensible heat, taking into account a heat amount released to the outside of the blast furnace due to a blow-by; and a step of estimating a heat amount held by a core coke present in the blast furnace, estimating the heat amount supplied to the molten pig iron in the blast furnace, taking into account the heat amount held by the core coke estimated.

Description

Technical Field

[0001] This invention relates to a method, apparatus, procedure, and operation method for estimating the heat supply to pig iron in a blast furnace. Background Technology

[0002] Typically, to ensure stable operation of a blast furnace, the temperature of molten pig iron needs to be maintained within a specified range. Specifically, when the molten pig iron temperature is low, the viscosity of the molten pig iron and the slag it produces increases, making it difficult for them to exit the taphole. Conversely, when the molten pig iron temperature is high, the Si concentration in the molten pig iron increases, further increasing its viscosity. This increases the risk of the molten pig iron sticking to the tuyeres and causing tuyere meltdown. Therefore, to ensure stable blast furnace operation, fluctuations in the molten pig iron temperature need to be suppressed. Against this backdrop, various methods for estimating the heat supplied to the blast furnace and the temperature of the molten pig iron have been proposed. Specifically, Patent Document 1 discloses a furnace heat control method for a blast furnace, characterized in that the furnace heat index displacement at the current moment from the furnace heat index reference level corresponding to the target molten pig iron temperature, the unloading speed displacement at the current moment from the unloading speed reference level at the furnace top corresponding to the target molten pig iron temperature, and the influence time of the two displacements on the molten pig iron temperature are sequentially estimated to determine the molten pig iron temperature after a specific time. Based on the estimation result, furnace heat control operations are performed to reduce the variation of molten pig iron temperature. Furthermore, Patent Document 2 discloses a method for predicting the molten pig iron temperature of a blast furnace. This method predicts the future molten pig iron temperature based on operational data including actual values ​​of blast conditions data (at least one of blast furnace blast temperature, blast humidity, blast volume, fine carbon injection amount, and oxygen enrichment amount), actual values ​​of interference factor data (at least including carbon dissolution amount), and actual values ​​of the molten pig iron temperature. The method is characterized by comprising: a data accumulation step, which accumulates operational data; a stable state prediction model construction step, which constructs a stable state prediction model to predict the molten pig iron temperature in a stable state based on the operational data accumulated in the data accumulation step; an unstable state prediction model construction step, which is a step of reducing the dimensionality of the stable state prediction model, wherein an unstable state prediction model is constructed to predict the molten pig iron temperature in an unstable state based on the operational data accumulated in the data accumulation step; and a molten pig iron temperature prediction step, which predicts the molten pig iron temperature based on the constructed stable state prediction model and the unstable state prediction model.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2-115311

[0006] Patent Document 2: Japanese Patent Application Publication No. 2008-144265 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] The likelihood of significant fluctuations in molten pig iron temperature is high when changes in the amount of molten pig iron produced, such as variations in the blast furnace operating conditions (e.g., the amount of blast furnace feed), change in the amount of pig iron relative to the heat supplied to the blast furnace. This is particularly true when, due to areas of high blast furnace resistance, gas concentrates in easily flowing areas, preventing uniform heating and reaction within the blast furnace – a phenomenon known as "leaking" – significant fluctuations in molten pig iron temperature occur. However, the method described in Patent Document 1 fails to consider factors such as the carry-over of sensible heat from the blast furnace feed, which is believed to change with variations in operating conditions. Therefore, it cannot accurately estimate the heat supplied to the pig iron when operating conditions change significantly. On the other hand, the method described in Patent Document 2 assumes that the accuracy of molten pig iron temperature estimation decreases when operating changes that have not been previously accumulated. Furthermore, with such low accuracy in molten pig iron temperature estimation, excessive heat supply is more likely, raising concerns about equipment malfunction. Additionally, from the perspective of reducing carbon dioxide emissions, excessive use of reducing materials as carbon sources is not preferable.

[0009] The present invention was made in view of the above-mentioned problems, and its object is to provide a method, apparatus, and procedure for estimating the heat supply to pig iron in the blast furnace with high accuracy, even under conditions of large variations in operating conditions, particularly in the event of leakage. Furthermore, another object of the present invention is to provide a method for operating a blast furnace that can appropriately maintain the heat supply to the pig iron in the blast furnace and can precisely control the temperature of the molten pig iron within a specified range, even under conditions of large variations in operating conditions, particularly in the event of leakage.

[0010] Methods for solving problems

[0011] The method for estimating the supply heat of the present invention is a method for estimating the supply heat of pig iron supplied to the blast furnace based on the heat supplied to the blast furnace and the production rate of molten pig iron in the blast furnace. It includes an estimation step, wherein the method estimates the change in sensible heat carried out by the gas passing through the furnace and the change in sensible heat brought in by the raw materials preheated by the gas passing through the furnace; and estimates the supply heat of pig iron to the blast furnace by considering the estimated changes in sensible heat carried out and brought in. The estimation step includes: estimating the changes in sensible heat carried out and brought in by considering the heat released outside the blast furnace due to leakage; and estimating the heat held by the core coke present in the blast furnace; and estimating the supply heat of pig iron to the blast furnace by considering the estimated heat held by the core coke.

[0012] It should be noted that the above estimation steps may include the following steps: calculating the product value by multiplying the specific heat of the furnace top gas by the difference between the furnace top gas temperature and the reference temperature of the furnace top gas temperature, dividing the product value by the ironmaking rate, and adding the resulting value to the above-mentioned sensible heat carried out. Thus, the heat released outside the blast furnace due to leakage is considered to estimate the above-mentioned sensible heat carried out.

[0013] In addition, the above estimation steps may include the following steps: by calculating the difference between the raw material temperature and the reference temperature of the furnace top gas temperature as a function of the raw material temperature, the heat released outside the blast furnace due to leakage is considered to estimate the above-mentioned sensible heat.

[0014] The supply heat estimation device of the present invention is a supply heat estimation device for estimating the heat of pig iron supplied to the blast furnace based on the heat supplied to the blast furnace and the production rate of molten pig iron in the blast furnace. It comprises: an estimation unit that estimates the change in sensible heat carried out by the gas passing through the furnace and the change in sensible heat brought in by the raw material preheated by the gas passing through the furnace, and estimates the heat of pig iron supplied to the blast furnace by taking into account the estimated changes in sensible heat carried out and brought in, the estimation unit estimates the changes in sensible heat carried out and brought in by taking into account the heat released to the outside of the blast furnace due to leakage, estimates the heat held by the core coke present in the blast furnace, and estimates the heat of pig iron supplied to the blast furnace by taking into account the estimated heat held by the core coke.

[0015] The supply heat estimation program of the present invention is a process in which a computer is executed to estimate the heat of pig iron supplied to the blast furnace based on the heat supplied to the blast furnace and the manufacturing rate of molten pig iron in the blast furnace. The computer performs the following estimation process: estimating the change in sensible heat carried out by the gas passing through the furnace and the change in sensible heat brought in by the raw materials preheated by the gas passing through the furnace; and estimating the heat of pig iron supplied to the blast furnace by considering the estimated changes in sensible heat carried out and brought in. The estimation process includes the following steps: estimating the changes in sensible heat carried out and brought in by considering the heat released outside the blast furnace due to leakage; estimating the heat held by the core coke present in the blast furnace; and estimating the heat of pig iron supplied to the blast furnace by considering the estimated heat held by the core coke.

[0016] The blast furnace operation method of the present invention includes the following steps: controlling the heat supplied to the blast furnace based on the heat of pig iron supplied to the blast furnace estimated by the heat supply estimation method of the present invention.

[0017] Invention Effects

[0018] According to the method, apparatus, and procedure for estimating the heat supply of the blast furnace according to the present invention, the heat supply to the pig iron supplied to the blast furnace can be estimated with high accuracy even when there are large changes in operating conditions, especially when leakage occurs. Furthermore, the blast furnace operation method according to the present invention can appropriately maintain the heat supply to the pig iron in the blast furnace even when there are large changes in operating conditions, especially when leakage occurs, and can precisely control the temperature of the molten pig iron within a specified range. Attached Figure Description

[0019] Figure 1 This is a block diagram showing the configuration of a furnace heat control device as one embodiment of the present invention.

[0020] Figure 2 This is a flowchart illustrating the process of furnace heat control as one embodiment of the present invention.

[0021] Figure 3 This is a graph illustrating an example of the relationship between conventional indices and the furnace heat index of the present invention and the temperature difference relative to the reference molten pig iron temperature. Detailed Implementation

[0022] Hereinafter, with reference to the accompanying drawings, the configuration and operation of a furnace heat control device, which is an embodiment of the present invention, applies the heat supply estimation method and heat supply estimation device of the present invention.

[0023] [constitute]

[0024] First, refer to Figure 1The configuration of a furnace heat control device, which is one embodiment of the present invention, will be described. Figure 1 This is a block diagram illustrating the configuration of a furnace heat control device as one embodiment of the present invention. Figure 1 As shown, the furnace heat control device 1, as one embodiment of the present invention, is composed of an information processing device such as a computer. By controlling the heat supplied to the molten metal inside the blast furnace 2 from the tuyeres located at the bottom of the blast furnace 2, the temperature of the molten pig iron produced inside the blast furnace 2 is controlled within a specified range. The furnace heat control device 1 functions as the heat supply estimation device of the present invention.

[0025] The furnace heat control device 1, with this configuration, can accurately estimate the heat supplied to the pig iron in the blast furnace 2 even when the operating degree of the blast furnace 2 changes significantly, especially when leakage occurs. Using the estimated results, it appropriately maintains the heat supplied to the pig iron in the blast furnace 2, and accurately controls the temperature of the molten pig iron within a specified range. Hereinafter, refer to... Figure 2 The process of furnace heat control processing as one embodiment of the present invention will be described.

[0026] It should be noted that the operation of the furnace heat control device 1 shown below is achieved as follows: the CPU or other arithmetic processing unit within the information processing unit constituting the furnace heat control device 1 loads program 1a from a storage unit such as ROM to a temporary storage unit such as RAM, and executes the loaded program 1a. Program 1a may also be provided as an installable or executable file stored on a computer-readable recording medium such as a CD-ROM, floppy disk, CD-R, or DVD. Program 1a may also be provided by storing it on a computer connected to a network such as a telecommunications line (e.g., the Internet), a telephone communication network (e.g., a mobile phone), or a wireless communication network (e.g., WiFi), and downloading it from the network.

[0027] [Furnace thermal control treatment]

[0028] Figure 2 This is a flowchart illustrating the process of furnace heat control as one embodiment of the present invention. Figure 2In the flowchart shown, starting from the moment the execution command for the furnace heat control process is input to the furnace heat control device 1, the furnace heat control process, in addition to the conventional step S1 which estimates the heat supplied to the blast furnace based on the reaction heat balance (heat generated by reaction, heat absorbed by reaction), sensible heat of the blast air, and heat loss (heat removed from the furnace body, etc.), also performs steps S2, S3, and S4. These processes are then integrated before proceeding to step S5, which estimates the heat supplied. Step S1, which estimates the heat supplied to the blast furnace based on the reaction heat balance (heat generated by reaction, heat absorbed by reaction), sensible heat of the blast air, and heat loss (heat removed from the furnace body, etc.), has been performed conventionally, and the heat supplied at this time is set as Q0. A preferred example of the process for step S1 will be explained later.

[0029] In step S2, the furnace heat control device 1 estimates the sensible heat (sensible heat carried out by the gas) Q7 carried out from the lower part of the blast furnace 2 to the upper part of the blast furnace 2 by the gas (gas passing through the furnace). Specifically, the sensible heat Q7 carried out by the gas (MJ / tp: heat per ton of pig iron. Hereinafter, when referred to as tp, it indicates the number of tons of pig iron) can be calculated by (1) multiplying the temperature difference between the estimated temperature (theoretical combustion temperature) of the gas burning in front of the tuyeres and the reference temperature representing the temperature of the upper part of the lower part of the blast furnace by the specific heat of the gas, (2) multiplying the specific heat of the gas at the top of the furnace by the difference between the temperature of the gas at the top of the furnace (exhaust temperature at the top of the furnace) and the reference temperature of the gas at the top of the furnace, and (3) dividing the value obtained by adding the first product value and the second product value by the ironmaking rate, as shown in the following mathematical formula (1). By adding the first and second product values ​​and dividing the result by the iron-making rate, the heat released outside the furnace due to leakage without exchanging heat with the raw materials can be evaluated with high precision for the sensible heat Q7 carried out by the gas. Thus, step S2 is completed, and the process proceeds to step S5.

[0030]

[0031] Here, C bosh,i This indicates the specific heat (MJ / m³) of gas type i (nitrogen, carbon monoxide, hydrogen) in the gas passing through the furnace (furnace gas). 3 / ℃), C top,i This represents the specific heat (MJ / m³) of gas type i (nitrogen, carbon monoxide, carbon dioxide, hydrogen, water vapor) in the furnace top gas. 3 / ℃), V bosh,i This indicates the flow rate (m³) of gas type i passing through the furnace. 3 (stp) / minute)(m 3 (stp): Volume at 0℃ and 1 atm (atmosphere), Vtop,i The flow rate (m³) of gas type i in the gas at the furnace top 3 (stp) / minute), TFT represents the theoretical combustion temperature (°C), T base T represents the reference temperature (°C) (800–1200°C, preferably 900–1000°C). top T represents the temperature of the gas at the furnace top (°C). top,base The reference temperature (°C) representing the furnace top gas temperature (80–300°C, preferably 100–200°C), Pig represents the iron-making rate (tp / minute), α bosh ,α top These represent the influence coefficients that change according to blast furnace 2. Their values ​​can be obtained, for example, from a host computer 3, such as a process computer connected to the furnace thermal control device 1 via a telecommunications line.

[0032] In step S3, the furnace heat control device 1 estimates the sensible heat (material-carried sensible heat) Q8 brought into the lower part of the blast furnace 2 by the raw material supplied from the upper part to the lower part. Specifically, the material-carried sensible heat Q8 (MJ / tp) can be expressed as shown in the following mathematical formula (2) by comparing the raw material temperature T1 (=1450~1500℃) at the lower end of the weld band with the reference temperature T base The temperature difference is calculated by multiplying the specific heat of the raw material. It should be noted that the raw material temperature T1, as shown in the following mathematical formula (3), becomes the furnace top gas temperature T. top The reference temperature T of the gas temperature at the furnace top top,base The difference is a function. Based on this setting of the raw material temperature T1, since the decrease in raw material temperature T1 due to heat released outside the furnace due to leakage can be considered, it is possible to accurately evaluate situations where the raw material becomes poorly heated due to leakage, and where the heat carried into the lower part of the furnace by the raw material decreases. Therefore, step S3 is completed, and the process proceeds to step S5.

[0033] Q8=β·{Σ(C j ·R j )}·(T1-T base (2)

[0034] Here, C j R represents the specific heat (MJ / kg / ℃) of raw material j (coke, pig iron, slag). j T represents the original unit of raw material j (kg / tp), T1 represents the raw material temperature at the lower end of the weld strip (°C), T base β represents the reference temperature (°C), and β represents the influence coefficient caused by the change in blast furnace 2. Their values ​​can be obtained, for example, from the host computer 3.

[0035] T1=f(T top -Ttop,base (3)

[0036] In step S4, the furnace heat control device 1 estimates the heat retained by the coke in the lower part of the blast furnace 2 (coke retention heat) Q9. Specifically, the coke retention heat Q9 (MJ / tp) can be obtained by subtracting the amount of combustion consumption and carbon discharged in the form of dust from the original coke unit per ton of molten pig iron, multiplied by the difference between the reference temperature and the theoretical combustion temperature and the specific heat C of the coke. coke The result is given by the mathematical expression (4) shown below. Thus, step S4 is completed, and we proceed to step S5.

[0037]

[0038] Here, C coke T represents the specific heat of coke (MJ / kg / ℃), TFT represents the theoretical combustion temperature (℃), and T represents the theoretical combustion temperature. base CR represents the reference temperature (°C), and CR represents the coke ratio (kg / tp). burn The carbon-to-fuel ratio before the air outlet (the amount of oxygen in the supply air plus the amount of oxygen consumed before the air outlet due to humidification) (kg / tp), PCR represents the carbon-to-fuel ratio of the fine powder (kg / tp), C inPC C represents the carbon ratio in micronized charcoal. sol The carbon solubility ratio (kg / tp) is represented by C, and the dust ratio (kg / tp) is represented by Dust. indust γ represents the carbon ratio in the dust, and δ represents the influence coefficients caused by the change in blast furnace 2. Their values ​​can be obtained, for example, from the host computer 3.

[0039] In step S5, the furnace heat control device 1 uses the supplied heat Q0 estimated in step S1, the gas-carried sensible heat Q7 estimated in steps S2-S4, the raw material-carried sensible heat Q8, and the coke retention heat Q9 to estimate the heat of pig iron supplied to the blast furnace 2. Specifically, the furnace heat control device 1 calculates the furnace heat index T corresponding to the heat of pig iron supplied to the blast furnace 2 by substituting the supplied heat Q0 estimated in step S1, the gas-carried sensible heat Q7 estimated in steps S2-S4, the raw material-carried sensible heat Q8, and the coke retention heat Q9 into the following mathematical formula (5). Q (MJ / tp). Thus, step S5 is completed, and the process proceeds to step S6.

[0040] T Q =Q0-Q7+Q8-Q9…(5)

[0041] Here, Q0 represents the heat supplied to the blast furnace using the reaction heat balance (reaction generation heat, reaction endothermic heat), sensible heat of the blast air, and heat loss (heat removed from the furnace body, etc.). This can be applied to the estimation method used in most cases in the previous estimation of the supplied heat, but as a preferred method, mathematical formula (6) can be listed.

[0042] Q0 = Q1 + Q2 - Q3 - Q4 - Q5 - Q6…(6)

[0043] Here, Q1 represents the heat of combustion of the coke at the front end of the tuyeres (MJ / tp). The heat of combustion Q1 can be calculated by dividing the heat generated by the combustion of the coke, calculated based on the amount of oxygen supplied from the tuyeres to the blast furnace per unit time, by the amount of molten pig iron produced per unit time.

[0044] Additionally, Q2 represents the sensible heat of the blast air fed into the blast furnace via the tuyeres (MJ / tp). The sensible heat of the blast air Q2 can be calculated by determining the heat fed into the blast furnace per unit time using the blast air volume and temperature, and then dividing that value by the amount of molten pig iron produced per unit time.

[0045] Additionally, Q3 represents the heat of reaction loss (MJ / tp). This value can be calculated, for example, by determining the amount of carbon lost based on the composition of the gas at the furnace top, as described in Patent Document 1. The heat of reaction loss Q3 can be calculated by dividing this heat of reaction loss by the amount of molten pig iron produced per unit time.

[0046] Additionally, Q4 represents the heat of decomposition (MJ / tp) of the wet components mainly contained in the supply air. The heat of decomposition Q4 can be calculated by dividing the heat of decomposition obtained from the measurement of the wet components in the supply air by the amount of molten pig iron produced per unit time.

[0047] Additionally, Q5 represents the heat loss from the furnace body (e.g., heat loss due to cooling water) (MJ / tp). As the heat loss, when the heat loss due to cooling water is calculated, the heat loss Q5 can be calculated by dividing the heat loss per unit time caused by cooling water by the amount of cooling water and the temperature difference between the inlet and outlet sides of the cooling water in the blast furnace body, and then dividing the calculated heat loss by the amount of molten pig iron produced in that unit time.

[0048] Additionally, Q6 represents the heat of decomposition of the reducing material blown in from the duct per unit time (MJ / tp). The heat of decomposition Q6 can be calculated by dividing the heat of decomposition by the amount of molten pig iron produced per unit time.

[0049] In step S6, the furnace heat control device 1 controls the heat supplied from the tuyeres to the blast furnace 2 based on the heat of the pig iron supplied to the blast furnace 2 estimated in step S5, thereby appropriately maintaining the heat of the pig iron supplied to the blast furnace 2 and controlling the temperature of the molten pig iron within a specified range. Thus, step S6 is completed, and the series of furnace heat control processes ends.

[0050] As explained above, in the furnace heat control process of one embodiment of the present invention, the furnace heat control device 1 estimates the change in sensible heat carried out to the upper part of the blast furnace due to the gas passing through the furnace, and the change in sensible heat carried in to the lower part of the blast furnace by the raw materials preheated by the gas passing through the furnace. Taking into account the estimated changes in sensible heat carried out and carried in, the heat of pig iron supplied to the blast furnace is estimated. Furthermore, the furnace heat control device 1 estimates the changes in sensible heat carried out and carried in by considering the heat released outside the blast furnace due to leakage, estimates the heat held by the core coke present in the blast furnace, and estimates the heat of pig iron supplied to the blast furnace by considering the estimated heat held by the core coke. Therefore, even when there are large changes in the blast furnace operating parameters, such as the air flow rate, especially when leakage occurs, the heat of pig iron supplied to the blast furnace can be estimated with high accuracy. Furthermore, this allows for the appropriate maintenance of the heat supplied to the pig iron in the blast furnace even when there are significant changes in operating conditions, especially in the event of leakage, and enables the precise control of the molten pig iron temperature within the specified range.

[0051] [Example]

[0052] exist Figure 3 The diagram shows a comparison of the furnace heat index (estimated using Q1 to Q6) and the furnace heat index of the present invention (estimated using Q1 to Q9) at the time when leakage would occur, with the actual molten pig iron temperature (the difference between the actual and reference molten pig iron temperatures). Figure 3 As shown, for the furnace heat index of the present invention (example of the present invention), compared with the conventional furnace heat index (comparative example), it can be confirmed that there is a certain correlation between the furnace heat index and the molten pig iron temperature (the difference from the reference molten pig iron temperature). Furthermore, Table 1 summarizes the standard deviation of the difference between the estimated molten pig iron temperature and the actual molten pig iron temperature, considering various factors. It can be seen that compared with the case where only Q1 to Q6 are used as conventional furnace heat indices to estimate the furnace heat index (comparative example), the estimation accuracy is improved when considering the heat released outside the furnace due to leakage (example of the present invention, where the furnace heat index is estimated using Q1 to Q9). This confirms that by using the furnace heat index of the present invention, even with large changes in operating conditions, especially when leakage occurs, the heat supplied to the pig iron in the blast furnace can be appropriately maintained, and the molten pig iron temperature can be controlled with high precision within a specified range.

[0053] [Table 1]

[0054] (Table 1)

[0055]

[0056] The embodiments of the invention made by the inventors have been described above, but the present invention is not limited to the description and drawings that constitute a part of the disclosure of the present invention based on these embodiments. That is, all other embodiments, examples, and applications made by those skilled in the art based on these embodiments are included within the scope of the present invention.

[0057] Industrial availability

[0058] According to the present invention, a method, apparatus, and procedure for estimating the heat supply to the pig iron in the blast furnace with high accuracy can be provided, even under conditions of significant operational variation, particularly in the event of leakage. Furthermore, according to the present invention, a method for operating a blast furnace can be provided that appropriately maintains the heat supply to the pig iron in the blast furnace and can precisely control the temperature of the molten pig iron within a specified range, even under conditions of significant operational variation, particularly in the event of leakage.

[0059] Symbol Explanation

[0060] 1. Furnace thermal control device

[0061] 1a Program

[0062] 2 Blast Furnace

[0063] 3. Host Computer

Claims

1. A method for estimating the heat supply, which estimates the heat supply to the pig iron in the blast furnace based on the heat supplied to the blast furnace and the rate of molten pig iron production in the blast furnace, wherein, The method for estimating the supplied heat includes an estimation step, wherein the changes in sensible heat carried out by the gas passing through the furnace and the changes in sensible heat brought in by the raw materials preheated by the gas passing through the furnace are estimated, and the heat supplied to the pig iron in the blast furnace is estimated by considering the estimated changes in sensible heat carried out and brought in. The estimation step includes: estimating the changes in the sensible heat carried out and the sensible heat carried in by taking into account the heat released to the outside of the blast furnace due to leakage; and estimating the heat held by the core coke present in the blast furnace, and estimating the heat supplied to the pig iron in the blast furnace by taking into account the estimated heat held by the core coke.

2. The method for estimating the supplied heat according to claim 1, wherein the estimation step includes the following steps: multiplying the specific heat of the furnace top gas by the difference between the furnace top gas temperature and the reference temperature of the furnace top gas temperature to calculate the product value, dividing the product value by the ironmaking rate, and adding the obtained value to the sensible heat carried out, thereby estimating the sensible heat carried out by considering the heat released outside the blast furnace due to leakage.

3. The heat-supply amount estimation method according to claim 1 or 2, wherein The estimation step includes the following steps: by calculating the difference between the raw material temperature and the reference temperature of the furnace top gas temperature as a function of the raw material temperature, the amount of heat released outside the blast furnace due to leakage is estimated to bring in sensible heat.

4. A heat supply estimation device, which estimates the heat supplied to the blast furnace based on the heat supplied to the blast furnace and the rate of molten pig iron production in the blast furnace, wherein... The heat supply estimation device includes: an estimation unit that estimates the change in sensible heat carried out by the gas passing through the furnace and the change in sensible heat brought in by the raw materials preheated by the gas passing through the furnace, and estimates the heat supplied to the pig iron in the blast furnace by taking into account the estimated changes in sensible heat carried out and brought in. The estimation unit estimates the changes in the sensible heat carried out and the sensible heat carried in by considering the heat released outside the blast furnace due to leakage, estimates the heat held by the core coke in the blast furnace, and estimates the heat supplied to the pig iron in the blast furnace by considering the estimated heat held by the core coke.

5. A computer-readable recording medium for recording a heat supply estimation program, said heat supply estimation program being a process that causes a computer to execute a heat supply estimation program to estimate the heat supplied to the blast furnace based on the heat supplied to the blast furnace and the rate of molten pig iron production in the blast furnace, wherein... The computer performs the following estimation process: estimating the change in sensible heat carried out by the gas passing through the furnace and the change in sensible heat brought in by the raw materials preheated by the gas passing through the furnace; and taking into account the estimated changes in sensible heat carried out and brought in, estimating the heat supplied to the pig iron in the blast furnace. The estimation process includes the following steps: estimating the changes in the sensible heat carried out and the sensible heat carried in by considering the heat released outside the blast furnace due to leakage; estimating the heat held by the core coke present in the blast furnace; and estimating the heat supplied to the pig iron in the blast furnace by considering the estimated heat held by the core coke.

6. A method of operating a blast furnace, comprising the following steps: controlling the heat supplied to the blast furnace based on the heat of pig iron supplied to the blast furnace estimated by the heat supply estimation method according to any one of claims 1 to 3.

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