A method for estimating the change in the weighted mean Rsav of the reduction rate at the start of fusion.

Abstract

Weighted average value Rs of the reduction rate at the start of fusion av This provides a means to estimate changes in early on. [Solution] The weighted average value Rs of the reduction rate at the start of fusion of the charged iron-containing raw material charged into the blast furnace. av A method for estimating the change in Rs, comprising: a first step of obtaining the correlation between the component content of the sintered ore and the reduction rate at the start of fusion for each component of the sintered ore; and a second step of calculating the weighted average value Rs of the reduction rate at the start of fusion of the charged iron-containing raw material relative to the standard iron-containing raw material, from the difference between a first multiplicative value obtained by multiplying a first standard mixing ratio and a standard reduction rate at the start of fusion and a second multiplicative value obtained by multiplying a first charging mixing ratio and a charging reduction rate at the start of fusion. av The process includes a second step of estimating the change in the charging fusion start rate. The charging fusion start rate is a value obtained by correcting the standard fusion start rate by the amount of change in the fusion start rate calculated based on the change in the mixing ratio of each component from the second standard mixing ratio to the second charging mixing ratio and the correlation obtained in the first step.

Description

[Technical Field]

[0001] This invention relates to the weighted average value Rs of the reduction rate at the start of fusion of charged iron-containing raw materials charged into a blast furnace. av This concerns a method for estimating changes in [the relevant variable]. [Background technology]

[0002] In a blast furnace, iron-containing raw materials such as ore (sintered ore, pellets, and lump ore) and coke, which acts as a reducing agent and fuel, are alternately charged into the furnace from the top, while hot air is blown in from tuyeres at the bottom of the furnace along with auxiliary fuels such as pulverized coal. The ore and coke charged from the top of the furnace (hereinafter collectively referred to as "charges") form alternating layers of ore and coke, respectively. As the load descends within the blast furnace, the ore and coke gradually descend towards the bottom of the furnace, being heated and heated by the reducing gas rising from the bottom.

[0003] As the ore material descends in the blast furnace while being heated and reduced, it softens and begins to fuse upon reaching the bottom of the furnace, forming an ore fusion layer. In the ore fusion layer, the voids between the ore material materials decrease, worsening the permeability of the reducing gas. Therefore, the reducing gas rises towards the top of the furnace, passing through the coke layer adjacent to the ore fusion layer. The region in the blast furnace where the ore fusion layer exists (including the coke layer adjacent to the ore fusion layer) is called the fusion zone. Consequently, the shape of the fusion zone has a very significant impact on the permeability of the blast furnace.

[0004] Patent Document 1 describes the weighted average value Rs of the reduction rate at the start of fusion of multiple types of iron-containing raw materials. av The lower limit Rs min As described above, a method for operating a blast furnace is disclosed, which involves charging a blast furnace with multiple types of iron-containing raw materials, whose blends have been designed using a blending design method for designing the blends of multiple types of iron-containing raw materials, in order to form an iron-containing raw material layer. The reduction rate at the start of fusion refers to the reduction rate at the fusion start temperature (Ts). [Prior art documents] [Patent Documents]

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Document

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] Weighted average value Rs of reduction rate at the start of sintering av There is a need for means to estimate the change of at an early stage. If it can be estimated early, actions to improve the operation status of the blast furnace can be promptly implemented. In Patent Document 1, the reduction rate at the start of sintering is measured by a load softening test, which takes time for measurement, so the change of the weighted average value Rs av cannot be estimated early.

Means for Solving the Problems

[0008] In order to solve the above problems, (1) the weighted average value Rs of the reduction rate at the start of sintering of the charged iron-containing raw materials charged into the blast furnace avA method for estimating the change of av , wherein sintered ore contained in the reference iron-containing raw material charged into the blast furnace is defined as reference sintered ore, the blending ratio of the reference sintered ore to the reference iron-containing raw material is defined as the first reference blending ratio, the blending ratio of each component contained in the reference sintered ore is defined as the second reference blending ratio, and the reduction rate at the start of fusion of the reference sintered ore is defined as the reference reduction rate at the start of fusion. When the sintered ore contained in the charged iron-containing raw material is defined as charged sintered ore, the blending ratio of the charged sintered ore to the charged iron-containing raw material is defined as the first charged blending ratio, the blending ratio of each component contained in the charged sintered ore is defined as the second charged blending ratio, and the reduction rate at the start of fusion of the charged sintered ore is defined as the charged reduction rate at the start of fusion, a first step of obtaining in advance the correlation between the content of the component contained in the sintered ore and the reduction rate at the start of fusion of the sintered ore for each component of the sintered ore, and the weighted average value Rs of the reduction rate at the start of fusion of the charged iron-containing raw material with respect to the reference iron-containing raw material from the difference between the first multiplication value obtained by multiplying the first reference blending ratio and the reference reduction rate at the start of fusion and the second multiplication value obtained by multiplying the first charged blending ratio and the charged reduction rate at the start of fusion av A second step of estimating the change of av , and the charged reduction rate at the start of fusion is a value obtained by correcting the reference reduction rate at the start of fusion by the change amount of the reduction rate at the start of fusion calculated based on the change in the blending ratio of each component from the second reference blending ratio to the second charged blending ratio and the correlation obtained in the first step. A method for estimating the change of the weighted average value Rs of the reduction rate at the start of fusion, characterized in that av A method for estimating the change of .

[0009] (2) The first charged blending ratio and the second charged blending ratio are obtained by continuously analyzing the components of the charged iron-containing raw material on a belt conveyor that conveys the blast furnace raw material upward toward the top of the blast furnace. The method for estimating the weighted average value Rs of the reduction rate at the start of fusion according to (1) above, characterized in that av A method for estimating the change of .

[0010] (3) The components of the charged iron-containing raw material are continuously analyzed on a belt conveyor by a LIBS analyzer or a neutron beam component analyzer. The method for estimating the weighted average value Rs of the reduction rate at the start of fusion according to (2) above, characterized in that av A method for estimating the change of .

[0011] (4) The correlation obtained in the first step is a linear function in which the reduction rate at the start of fusion of the sintered ore decreases as the content of the component increases, characterized in that the weighted average value Rs of the reduction rate at the start of fusion described in (1) or (2) above. av A method for estimating changes in [something]. [Effects of the Invention]

[0012] According to the present invention, the weighted average value Rs of the reduction rate at the start of fusion of the charged iron-containing raw material to be charged into the blast furnace av Changes can be quickly estimated. [Brief explanation of the drawing]

[0013] [Figure 1] This is a correlation obtained using a large-scale data analysis method (corresponding to FeO). [Figure 2] This is a correlation obtained using a large-scale data analysis method (corresponding to Al2O3). [Figure 3] This is a correlation obtained using a large-scale data analysis method (corresponding to lime silica). [Figure 4] This information concerns the relationship between the reducing agent ratio (RAR) and the weighted average value Rsav, as measured in a blast furnace. [Figure 5] This graph shows the changes over time in the weighted mean values ​​Rsav and △RAR (Example). [Figure 6] This graph shows the changes over time in the weighted mean values ​​Rsav and △RAR (example). [Modes for carrying out the invention]

[0014] (Definition of terms) The "standard iron-containing raw material" can be any iron-containing raw material commonly used in stably operating blast furnaces. The iron-containing raw material must contain at least sintered ore, and may also contain lump ore, pellets, auxiliary materials, etc. Sintered ore must make up at least 60% by mass of the iron-containing raw material. The definition of iron-containing raw material is the same as below. "Standard sintered ore" refers to the sintered ore contained in the standard iron-containing raw material.

[0015] The "first standard mixing ratio" refers to the mixing ratio (mass%) of standard sintered ore to standard iron-containing raw materials. In other words, it is the content (mass%) of standard sintered ore when the standard iron-containing raw materials are set to 100% by mass. Here, a representative value (e.g., arithmetic mean, median, etc.) of the mixing ratio of sintered ore may be calculated based on the component analysis of multiple types of iron-containing raw materials sampled during stable operation, and this calculated representative value may be used as the "first standard mixing ratio." However, the mixing ratio of sintered ore contained in one type of iron-containing raw material sampled during stable operation may be used as the "first standard mixing ratio."

[0016] The "second standard mixing ratio" is the mixing ratio of each component contained in the standard sintered ore. The components are FeO, Al2O3, and CaO+SiO2 (hereinafter also referred to as lime silica). In other words, when the standard sintered ore is set to 100% by mass, the respective content (mass%) of FeO, Al2O3, and lime silica corresponds to the "second standard mixing ratio." Here, based on the component analysis of the sintered ore contained in each of the multiple types of iron-containing raw materials sampled during stable operation, a representative value of the content of each component may be calculated and this calculated representative value may be used as the "second standard mixing ratio." However, the content of each component of the sintered ore contained in one type of iron-containing raw material sampled during stable operation may also be used as the "second standard mixing ratio." Note that sintered ore may contain components other than FeO, Al2O3, and lime silica (e.g., MgO), but these will be ignored as they have little effect on the reduction rate at the start of fusion.

[0017] The "standard reduction rate at the start of fusion" refers to the reduction rate at the start of fusion of the standard sintered ore. A load softening test can be used to measure the reduction rate at the start of fusion of the standard sintered ore. The details of the load softening test are disclosed in Patent Document 1, so a detailed explanation will be omitted. Here, the reduction rate at the start of fusion may be determined for each of the sintered ores used when calculating the "first standard mixing ratio," and these representative values ​​(e.g., arithmetic mean, median, etc.) may be used as the "standard reduction rate at the start of fusion." However, the reduction rate at the start of fusion of a sintered ore of one type of iron-containing raw material sampled during stable operation may also be used as the "standard reduction rate at the start of fusion."

[0018] The above-mentioned information relating to the standard iron-containing raw materials (first standard mixing ratio, second standard mixing ratio, and standard reduction rate at the start of fusion) is base information and therefore must be obtained in advance before charging the iron-containing raw materials. In normal blast furnace operation, component analysis of the blast furnace raw materials charged into the blast furnace is performed on a daily basis, so calculating the first standard mixing ratio and the second standard mixing ratio is within the scope of normal work. Therefore, in claim 1, the invention is described assuming that the first standard mixing ratio, the second standard mixing ratio, and the standard reduction rate at the start of fusion have already been determined.

[0019] "Charged iron-containing raw materials" refers to iron-containing raw materials that will be charged into the blast furnace. "Charged sintered ore" refers to the sintered ore contained in the charged iron-containing raw material. The "first charging ratio" refers to the ratio (by mass) of the charged sintered ore to the charged iron-containing raw materials. The "second charging ratio" refers to the proportion (mass %) of each component contained in the charged sintered ore. The definitions of the components will not be repeated. "Reduction rate at the start of charging fusion" refers to the reduction rate of the charged sintered ore at the start of fusion.

[0020] Here, the weighted average value Rs of the reduction rate at the start of fusion of the charged iron-containing raw material. av This can be determined by measuring the mixing ratio of each raw material contained in the charged iron-containing raw material and the reduction rate at the start of fusion, as described in Patent Document 1 (see formula (I) below). The mixing ratio can be quickly obtained based on the component analysis performed daily during normal blast furnace operation. In contrast, the load softening test is time-consuming, making it impossible to quickly calculate the reduction rate at the start of fusion. Therefore, it is difficult to feedforward the results of the reduction rate calculation at the start of fusion into operational actions. This invention focuses on charged sintered ore contained in charged iron-containing raw materials and is characterized by establishing a method for estimating the reduction rate at the start of fusion of such charged sintered ore solely through component analysis, without relying on load softening tests.

[0021] Based on the definitions of "standard iron-containing raw material," "standard sintered ore," "first standard mixing ratio," "second standard mixing ratio," "standard reduction rate at the start of fusion," "charged iron-containing raw material," "charged sintered ore," "first charging mixing ratio," "second charging mixing ratio," and "reduction rate at the start of charging fusion," the weighted average value Rs of the reduction rate at the start of fusion of the charged iron-containing raw material charged into the blast furnace is calculated. av This section explains how to estimate changes in [the variable].

[0022] (Step S1) First, the correlation between the content of each component in the sintered ore and the reduction rate at the start of fusion of the sintered ore is obtained for each component of the sintered ore. As mentioned above, the components in the sintered ore are FeO, Al2O3, and lime silica. Therefore, the correlation between the FeO content and the reduction rate at the start of fusion of the sintered ore, the Al2O3 content and the reduction rate at the start of fusion of the sintered ore, and the lime silica content and the reduction rate at the start of fusion of the sintered ore are obtained.

[0023] By experimentally producing multiple types of sintered ore with different FeO content and measuring the reduction rate at the start of fusion for each sintered ore, a correlation corresponding to FeO can be obtained (hereinafter also referred to as the individual test method). It goes without saying that these sintered ores possess properties suitable for blast furnace charging. The reduction rate at the start of fusion of the sintered ore can be measured by the load softening test described above.

[0024] During blast furnace operation, sintered ore is sampled daily and its components are analyzed. By measuring the reduction rate at the start of fusion of the sintered ore along with this component analysis, a correlation with FeO can be obtained (hereinafter referred to as the large-scale data analysis method). The reduction rate at the start of fusion of the sintered ore can be measured by the load softening test described above. In this case, as illustrated in Figure 1, data can be obtained for sintered ores with nearly identical FeO content, but because a large number of sintered ores are sampled, the correlation can be appropriately obtained. The correlation can be obtained by fitting the acquired data to a linear function (as FeO content increases, the reduction rate at the start of fusion of the sintered ore decreases). In Figures 1 to 3, the reduction rate at the start of fusion is denoted as "Rs[%]".

[0025] Correlations corresponding to Al2O3 can also be obtained according to individual test methods or large-scale data analysis methods. In the large-scale data analysis method, as illustrated in Figure 2, data can be obtained for sintered ores with approximately the same Al2O3 content, but because the number of sintered ores sampled is large, the correlation can be appropriately obtained. The correlation can be obtained by fitting the acquired data to a linear function (where the reduction rate at the start of fusion of sintered ore decreases as the Al2O3 content increases).

[0026] For lime silica, correlations can be obtained according to individual test methods or large-scale data analysis methods. In the large-scale data analysis method, as illustrated in Figure 3, data can be obtained for sintered ores with approximately the same lime silica content, but because the number of sintered ores sampled is large, correlations can be appropriately obtained. The correlation can be obtained by fitting the acquired data to a linear function (where the reduction rate at the start of fusion of sintered ore decreases as the lime silica content increases).

[0027] The inventors obtained correlations corresponding to each component contained in the sintered ore using individual test methods. The slope of the linear function (correlation) corresponding to FeO was -1.9, the slope of the linear function (correlation) corresponding to Al2O3 was -4.38, and the slope of the linear function (correlation) corresponding to lime silica was -2.75. Figures 1 to 3, corresponding to the large-scale data analysis method, illustrate the linear functions obtained by the individual test methods with dotted lines.

[0028] Either individual test methods or large-scale data analysis methods may be used. In the case of large-scale data analysis methods, the correlation may be determined using the "sintered ore from multiple types of iron-containing raw materials sampled during stable operation" that was used to determine the first and second standard mixing ratios. Since component analysis of the sintered ore is performed when determining the second standard mixing ratio, the correlation can be determined using the results of this analysis. However, the correlation may also be determined using iron-containing raw materials different from the "sintered ore from multiple types of iron-containing raw materials sampled during stable operation" that was used to determine the first and second standard mixing ratios.

[0029] (Step S2) The weighted average value Rs of the reduction rate at the start of fusion of the charged iron-containing raw material relative to the standard iron-containing raw material is calculated from the difference between the first multiplicative value obtained by multiplying the first standard mixing ratio and the standard reduction rate at the start of fusion and the second multiplicative value obtained by multiplying the first charging mixing ratio and the reduction rate at the start of charging fusion. av We estimate the change. The technical significance of step S2 will be explained in detail with reference to the following equation (I). Equation (I) is the weighted average value Rs of the reduction rate at the start of fusion, which is taken from Patent Document 1. av This is the formula for calculating it.

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[0030] The weighted average value Rs of the reduction rate at the start of fusion when the blast furnace raw material changes from a standard iron-containing raw material to a charged iron-containing raw material. av The change in Rs is the weighted average value of the charged iron-containing raw material obtained from equation (I). av And the weighted average value Rs of the standard iron-containing raw materials obtained from equation (I) av It is calculated from the difference between the two. Here, the main component of the iron-containing raw material is sintered ore, which is made from multiple types of powdered ore that are natural minerals. Since the mixing ratio of these powdered ores is changed on a daily basis, the reduction rate at the start of fusion of the iron-containing raw material changes over time. On the other hand, iron-containing raw materials other than sintered ore (lump ore, pellets, auxiliary materials) have a lower iron content than sintered ore, and their composition changes are inherently smaller. Also, the brand of iron-containing raw materials other than sintered ore changes less frequently than that of sintered ore. Therefore, the weighted average value Rs of the reduction rate at the start of fusion is... av When considering the changes in equation (I), we only need to focus on the sintered ore term. In other words, in equation (I), the term for iron-containing raw materials (pellets, etc.) excluding the sintered ore can be considered to remain unchanged.

[0031] Therefore, the difference between the product of the mixing ratio of the standard sintered ore to the standard iron-containing raw material and the reduction rate of the standard sintered ore at the start of fusion (in other words, the first multiplicative value obtained by multiplying the first standard mixing ratio and the standard reduction rate at the start of fusion) and the product of the mixing ratio of the charged sintered ore to the charged iron-containing raw material and the reduction rate of the charged sintered ore at the start of fusion (in other words, the second multiplicative value obtained by multiplying the first charged mixing ratio and the reduction rate at the start of charged fusion) is calculated as the weighted average value Rs of the reduction rates at the start of fusion. av This can be considered a change in that respect.

[0032] In normal blast furnace operation, the iron-containing raw materials charged into the blast furnace are subjected to component analysis. From the results of this component analysis, the mixing ratio of each component (FeO, Al2O3, and lime silica) contained in the sintered ore (the second charging mixing ratio) can be determined. Therefore, it is possible to understand the change in the mixing ratio of each component from the second standard mixing ratio to the second charging mixing ratio, that is, how much the content of FeO, Al2O3, and lime silica changes when switching from standard sintered ore to charged sintered ore.

[0033] If the changes in these components are known, the changes in the reduction rate at the start of fusion of the sintered ore corresponding to FeO, the changes in the reduction rate at the start of fusion of the sintered ore corresponding to Al2O3, and the changes in the reduction rate at the start of fusion of the sintered ore corresponding to lime silica can be determined from the correlation obtained in step S1. The sum of these changes can be considered as the "change in the reduction rate at the start of fusion" due to the sintered ore changing from a reference sintered ore to a charged sintered ore. By correcting the reduction rate at the start of fusion of the reference sintered ore (reference reduction rate at the start of fusion) with this change in the reduction rate at the start of fusion, the reduction rate at the start of fusion of the charged sintered ore (charged reduction rate at the start of fusion) can be estimated.

[0034] In other words, since the reduction rate at the start of fusion of charged sintered ore can be estimated from the component analysis of sintered ore obtained routinely during blast furnace operation, it becomes unnecessary to conduct time-consuming load softening tests on the charged sintered ore.

[0035] For example, let's assume that the FeO, Al2O3, and lime silica content in the standard sintered ore is 7% by mass (second standard blending ratio), 1.5% by mass (second standard blending ratio), and 14% by mass (second standard blending ratio), respectively. Furthermore, let's assume that the correlation with FeO is a linear function with a slope of -1.9, the correlation with Al2O3 is a linear function with a slope of -4.38, and the correlation with lime silica is a linear function with a slope of -2.75. Furthermore, it is assumed that the reduction rate at the start of fusion of the reference sintered ore (reference reduction rate at the start of fusion) is 68%. These are standard pieces of information and are assumed to be prepared in advance.

[0036] On the other hand, when the blast furnace is operated by charging the iron-containing raw material into it, the component analysis results of the charged sintered ore show that "FeO content: 6% by mass (second charging blending ratio), Al2O3 content: 1.8% by mass (second charging blending ratio), lime silica content: 15% by mass (second charging blending ratio)."

[0037] Comparing the reference sintered ore and the charged sintered ore, the FeO content decreased by 1 mass, and based on the correlation with FeO, it can be estimated that the reduction rate at the start of fusion increased by 1.9%. The Al2O3 content increased by 0.3 mass%, and based on the correlation with Al2O3, it can be estimated that the reduction rate at the start of fusion decreased by 1.314%. The lime silica content increased by 1 mass%, and based on the correlation with lime silica, it can be estimated that the reduction rate at the start of fusion decreased by 2.75%.

[0038] By summing up the changes in the reduction rate at the start of fusion, the decrease in the reduction rate at the start of fusion (2.164) can be determined. By subtracting 2.164 from the reduction rate at the start of fusion of the reference sintered ore (reference reduction rate at the start of fusion), the reduction rate at the start of fusion of the charged sintered ore (charged reduction rate at the start of fusion) can be calculated.

[0039] In typical steel mills, component analysis of raw materials charged into the blast furnace is performed every few hours (for example, every four hours). Therefore, based on the component analysis results of the charged iron-containing raw materials, the weighted average value Rs av Changes in Rs can be quickly grasped. Therefore, the weighted mean Rs av By investigating the relationship between the air permeability and the operational parameters that affect it in advance, necessary operational actions can be implemented feedforward. "Operational parameters that affect air permeability" include the reducing agent ratio (RAR) and the coke ratio (CR).

[0040] Figure 4 shows the reducing agent ratio (RAR) and weighted average value Rs measured in a certain blast furnace. avThis chart shows the relationship between RAR (kg / tp) and the weighted average Rs. av (%). By fitting the plotted data to a linear function, the reducing agent ratio (RAR) and the weighted mean Rs can be calculated. av The relationship can be defined based on this linear function. When the mixing ratio and components of the sintered ore change (in other words, the weighted average value Rs av When the reducing agent ratio (RAR) changes, the change can be quantitatively understood. Based on this, by adjusting the reducing agent ratio (RAR), the heat level of the blast furnace can be kept constant, enabling stable operation.

[0041] By continuously performing component analysis on the charged iron-containing raw material on a belt conveyor that carries the blast furnace raw materials upward toward the top of the blast furnace, information regarding the mixing ratio of charged sintered ore to the charged iron-containing raw material (first charging mixing ratio) and the mixing ratio of each component contained in the charged sintered ore (second charging mixing ratio) may be obtained. This will result in a weighted average value Rs av This allows for more rapid detection of changes. Continuous analysis equipment can include LIBS analyzers (Laser Induced Breakdown Spectroscopy) and neutron beam component analyzers.

[0042] Furthermore, the method of obtaining information regarding the mixing ratio of charged sintered ore to charged iron-containing raw materials (first charging mixing ratio) and the mixing ratio of each component contained in the charged sintered ore (second charging mixing ratio) by performing component analysis at intervals of several hours, as described above in typical steel mills, can be defined as a "discontinuous analysis method." The method of obtaining information regarding the mixing ratio of charged sintered ore to charged iron-containing raw materials (first charging mixing ratio) and the mixing ratio of each component contained in the charged sintered ore (second charging mixing ratio) by continuously performing component analysis of the charged iron-containing raw materials on a conveyor belt can be defined as a "continuous analysis method."

[0043] The present invention will be specifically described below with reference to examples. (Examples) The correlations exemplified in step S1 (correlation corresponding to FeO: a linear function with a slope of -1.9, correlation corresponding to Al2O3: a linear function with a slope of -4.38, correlation corresponding to lime silica: a linear function with a slope of -2.75) were obtained using the individual test methods described above. The sintered ore charged into blast furnace A was measured at a frequency of once every four hours and subjected to a general process analysis process, and the weighted average value Rs av Change (△Rs av ) was investigated. Needless to say, if at least one of the mixing ratio of charged sintered ore to charged iron-containing raw material (first charging mixing ratio) and the mixing ratio of each component contained in the charged sintered ore (second charging mixing ratio) changes from the standard sintered ore, the weighted average value Rs av This changes. Also, for blast furnace A, the weighted average value Rs av The relationship between the reducing agent ratio (RAR) and the reducing agent ratio (RAR) was investigated beforehand, and the change in the reducing agent ratio (RAR) (△RAR) was determined according to this relationship. The vertical axis represents RAR (kg / tp), and the weighted average value Rs is calculated. av In a graph with (%) on the horizontal axis, the aforementioned relationship is defined by a linear function with a slope of -3.8. Figure 5 shows △Rs av This graph shows the changes in and △RAR over time. The vertical axis at 0 corresponds to the standard iron-containing raw material. In other words, the graph in Figure 5 shows the change in △Rs relative to the standard. av And it shows how △RAR changes over time.

[0044] A feedforward action was taken to "change the reducing agent ratio (RAR) setting when △RAR increases to 2 kg / t or more." In this example, "feedforward" means taking action before the furnace temperature changes. The reason for setting the condition as "△RAR is 2 kg / t or more" is that △RAR = 2 kg / t corresponds to a molten iron temperature of △5°C, and it was determined that action to mitigate the change in molten iron temperature was necessary in blast furnace A. The number of feedforward actions per day was 2.0.

[0045] Needless to say, by adopting a continuous analysis method, the number of feedforward actions per day can be further increased. Furthermore, it is desirable to implement feedforward actions while taking into account the response time of the molten iron temperature.

[0046] (Reference example) As mentioned above, when the blast furnace raw material changes from a standard iron-containing raw material to a charged iron-containing raw material, the weighted average value Rs of the reduction rate at the start of fusion av The change in Rs is the weighted average value of the charged iron-containing raw material obtained from equation (I). av And the weighted average value Rs of the standard iron-containing raw materials obtained from equation (I) av It is calculated from the difference between the two. Equation (I) is shown again.

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[0047] For example, if the iron-containing raw material consists of two types, sintered ore and pellets, information corresponding to Figures 1 to 3 (correlation between the content of components in the pellets and the reduction rate at the start of fusion of the pellets) and reference information should also be obtained for the pellets. When the pellets contained in the reference iron-containing raw material are defined as reference pellets, the reference information includes the mixing ratio of the reference pellets to the reference iron-containing raw material, the mixing ratio of each component contained in the reference pellets, and the reduction rate at the start of fusion of the reference pellets. Since the component analysis results and mixing ratios can be obtained for each of the sintered ore and pellets contained in the charged iron-containing raw material using a continuous analyzer, the "weighted average value Rs of the reduction rate at the start of fusion" can be obtained. av When calculating the "change in pellets," the change in pellets can also be taken into consideration.

[0048] For the reference example, information equivalent to that in Figure 5 was obtained (the analysis method was continuous analysis using a neutron analyzer). The analysis frequency was one charge per raw material charge, and the results are shown in Figure 6. However, in Figure 6, the ΔRs is calculated using a moving average of 10 charges. av And △RAR is shown. Note that 10 charges are approximately 2 hours. Feedforward action could also be implemented in the example configuration.

Claims

1. The weighted average value Rs of the reduction rate at the start of fusion of the iron-containing raw material charged into the blast furnace. ａｖ A method for estimating the change in, The sintered ore contained in the standard iron-containing raw material charged into the blast furnace is defined as the standard sintered ore, the mixing ratio of the standard sintered ore to the standard iron-containing raw material is defined as the first standard mixing ratio, the mixing ratio of each component contained in the standard sintered ore is defined as the second standard mixing ratio, and the reduction rate at the start of fusion of the standard sintered ore is defined as the standard reduction rate at the start of fusion. When the sintered ore contained in the charged iron-containing raw material is defined as charged sintered ore, the mixing ratio of charged sintered ore to the charged iron-containing raw material is defined as the first charging mixing ratio, the mixing ratio of each component contained in the charged sintered ore is defined as the second charging mixing ratio, and the reduction rate of the charged sintered ore at the start of fusion is defined as the reduction rate at the start of fusion, The first step is to obtain the correlation between the content of the components contained in the sintered ore and the reduction rate at the start of fusion of the sintered ore, for each component of the sintered ore. The weighted average value Rs of the reduction rate at the start of fusion of the charged iron-containing raw material relative to the standard iron-containing raw material is obtained from the difference between the first multiplicative value obtained by multiplying the first standard blending ratio and the standard reduction rate at the start of fusion and the second multiplicative value obtained by multiplying the first charging blending ratio and the reduction rate at the start of charging fusion. ａｖ The second step is to estimate the change, It has, The reduction rate at the start of charging and fusion is a value obtained by correcting the standard reduction rate at the start of fusion by the amount of change in the reduction rate at the start of fusion calculated based on the change in the mixing ratio of each component from the second standard mixing ratio to the second charging mixing ratio and the correlation obtained in the first step. The weighted average value Rs of the reduction rate at the start of fusion, characterized by the above. ａｖ A method for estimating changes in [something].

2. The first charging ratio and the second charging ratio are obtained by continuously analyzing the components of the charged iron-containing raw material on a belt conveyor that carries the blast furnace raw material upwards toward the top of the blast furnace. Weighted average value Rs of the reduction rate at the start of fusion according to feature 1 ａｖ A method for estimating changes in [something].

3. A LIBS analyzer or neutron beam component analyzer is used to continuously analyze the components of the iron-containing raw material being charged onto the belt conveyor. Weighted average value Rs of the reduction rate at the start of fusion according to feature 2 ａｖ A method for estimating changes in [something].

4. The correlation obtained in the first step is a linear function in which the reduction rate at the start of fusion of the sintered ore decreases as the content of the component increases. Weighted average value Rs of the reduction rate at the start of fusion according to feature 1 or 2 ａｖ A method for estimating changes in [something].

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