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WO2025182165A1 - Procédé de fonctionnement de haut-fourneau - Google Patents

Procédé de fonctionnement de haut-fourneau

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Publication number
WO2025182165A1
WO2025182165A1 PCT/JP2024/040334 JP2024040334W WO2025182165A1 WO 2025182165 A1 WO2025182165 A1 WO 2025182165A1 JP 2024040334 W JP2024040334 W JP 2024040334W WO 2025182165 A1 WO2025182165 A1 WO 2025182165A1
Authority
WO
WIPO (PCT)
Prior art keywords
iron
pulverized coal
blast
molten iron
delay time
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/040334
Other languages
English (en)
Japanese (ja)
Inventor
尚人 安田
浩 三尾
薫 中野
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nippon Steel Corp
Original Assignee
Nippon Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nippon Steel Corp filed Critical Nippon Steel Corp
Priority to JP2025507016A priority Critical patent/JP7674698B1/ja
Publication of WO2025182165A1 publication Critical patent/WO2025182165A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21B—MANUFACTURE OF IRON OR STEEL
    • C21B5/00—Making pig-iron in the blast furnace

Definitions

  • the present disclosure relates to a method for operating a blast furnace.
  • This application claims priority based on Japanese Patent Application No. 2024-027364, filed on February 27, 2024, the contents of which are incorporated herein by reference.
  • iron raw materials sintered ore, pellets, lump ore, etc.
  • coke as a reducing agent and fuel
  • auxiliary fuel such as pulverized coal.
  • the iron raw materials and coke (hereinafter collectively referred to as "charge materials") charged from the top of the furnace form alternating layers of ore and coke, and as the charge materials are lowered, they gradually descend within the blast furnace toward the bottom, where they are heated and heated by gases rising from the bottom.
  • the iron raw materials descend while being heated and reduced within the blast furnace, melting and separating into pig iron and slag, which drip onto the hearth.
  • blast furnace operating methods have been studied that replace some of the iron raw material with reduced iron, with the aim of lowering the reducing agent ratio (RAR), improving the permeability of the ore layer, and improving the air and liquid permeability of the deadman coke by raising its temperature.
  • reduced iron include scrap, pig iron, reduced iron pellets (DRI, Direct Reduced Iron), and reduced iron briquettes (HBI, Hot Briquette Iron).
  • Pig iron is cold pig iron cast into blocks weighing approximately 10 to 30 kg for easier handling.
  • Patent Documents 1 to 3 describe blast furnace operation methods in which a portion of the iron raw material is replaced with reduced iron.
  • Patent Document 1 proposes a blast furnace operation method in which the amount of scrap charged from the furnace top to the periphery of the furnace is increased in order to maintain the reduction efficiency and high-temperature properties of the ore layer when the alumina content in sintered ore increases.
  • Patent Document 2 proposes a blast furnace operation method in which part of the iron raw material is replaced with scrap when the reduction degradation index (RDI) of the sintered ore or the drum strength (DI) of the coke deteriorates below a reference value, thereby maintaining permeability within the furnace.
  • Patent Document 3 proposes a blast furnace operation method in which the increase in pressure loss (deterioration of permeability) associated with an increase in the amount of pulverized coal injected is measured, and the amount of reduced iron charged is increased according to the increase.
  • RDI reduction degradation index
  • DI drum strength
  • Patent No. 3017009 Japanese Patent Application Laid-Open No. 2008-240028 Patent No. 3589016
  • the present disclosure aims to stably operate a blast furnace while suppressing fluctuations in the iron production rate and molten iron temperature when increasing or decreasing the amount of reduced iron charged in reduced iron operations, which involve charging reduced iron in place of a portion of the iron raw materials.
  • a blast furnace operating method includes: defining a first operation as an operation in which blast parameters and a pulverized coal ratio are the same as those in a reference operation but a reduced iron charging rate is different from those in the reference operation; and defining a second operation as an operation in which the reduced iron charging rate is the same as those in the first operation but a blast parameters and a pulverized coal ratio are different from those in the first operation.
  • the second operation includes a parameter estimation step of estimating blast parameters and a pulverized coal ratio in the second operation so that the iron output rate, molten iron temperature, and furnace top gas temperature are the same as those in the reference operation; and estimating the blast parameters and the pulverized coal ratio estimated in the parameter estimation step after a predetermined delay after switching from the reference operation to the first operation.
  • the amount of reduced iron charged in the first operation is greater than that in the standard operation.
  • the blending ratio of reduced iron contained in the iron raw material is 0.5 mass % or more and 50 mass % or less.
  • the change information acquisition step information on the time-dependent changes in both the molten iron temperature and the amount of iron tapped is acquired, and in the optimal delay time acquisition step, the predetermined time at which the time-dependent change in the molten iron temperature or the amount of iron tapped, whichever is more sensitive to delay time, is minimized is determined as the optimal delay time.
  • a third operation when an operation in which the blast specifications and the pulverized coal ratio are the same as those of the second operation and the charged amount of reduced iron is larger than those of the second operation is defined as a third operation, and an operation in which the charged amount of reduced iron is the same as those of the third operation and the blast specifications and the pulverized coal ratio are different from those of the third operation is defined as a fourth operation, the fourth operation has the same blast specifications and the pulverized coal ratio as those of the second operation, and the fourth operation has the same blast specifications and the pulverized coal ratio as those of the second operation, the fourth operation has the same blast specifications and the pulverized coal ratio as those of the second operation, and the fourth operation has the same blast specifications and the pulverized coal ratio as those of the second operation.
  • the method further includes a second change information acquisition step of acquiring information regarding changes over time in one or both of the molten iron temperature and the amount of molten iron tapped when the fourth operation is carried out, a second repetition step of performing the second change information acquisition step a plurality of times while changing the predetermined time, and a second optimal delay time acquisition step of determining, based on the information acquired in the second repetition step, the predetermined time at which the change over time in the molten iron temperature or the amount of molten iron tapped is minimized, as a second optimal delay time, and after switching from the second operation to the third operation, the fourth operation is started based on the air blowing specifications and pulverized coal ratio estimated in the second specification estimation step with a delay of the second optimal delay time.
  • the blast furnace operation method further includes a second parameter estimation step of estimating blast parameters and a pulverized coal ratio in the fourth operation such that the output rate, molten iron temperature, and furnace top gas temperature in the fourth operation are the same as those in the second operation, when a third operation is defined as an operation having the same blast parameters and a pulverized coal ratio as those in the second operation and a larger amount of reduced iron charged than those in the second operation, and a fourth operation is defined as an operation having the same amount of reduced iron charged as those in the third operation but a different blast parameters and pulverized coal ratio.
  • the fourth operation is started after a delay of the optimal delay time, based on the blast parameters and the pulverized coal ratio estimated in the second parameter estimation step.
  • the blast furnace when the amount of reduced iron charged is increased or decreased during reduced iron production, the blast furnace can be operated stably while suppressing fluctuations in the amount of pig iron produced and the temperature of the molten iron.
  • This allows the benefits of reduced iron charging to be fully realized, including improved reduction efficiency and permeability, and a reduced reducing agent ratio (RAR).
  • 1 is a schematic diagram of a blast furnace. 1 is a flowchart showing a method for operating a blast furnace. 1 shows the results of acquiring information on the changes over time in the molten iron temperature and the amount of iron tapped (Example).
  • 10 is a graph for explaining a method for determining an optimal delay time according to determination method 1.
  • 10 is a graph for explaining a method for determining an optimal delay time according to determination method 1.
  • 10 is a graph for explaining a method for determining an optimal delay time according to determination method 2.
  • 10 is a graph for explaining a method for determining an optimal delay time according to determination method 2.
  • ⁇ Outline of blast furnace configuration> 1 is a schematic diagram of a blast furnace according to the present embodiment.
  • the blast furnace 1 is a bell-less type blast furnace and includes a tuyere 2, an annular pipe 3, a blowpipe 4, a pulverized coal injection lance 5, a swivel chute 6, and a tap hole 7. Note that the present disclosure can also be applied to a bell-type blast furnace that does not have a swivel chute.
  • the tuyere 2 is an inlet port for blowing hot air generated in a hot stove (not shown) into the blast furnace 1, and multiple tuyere ports are provided along the circumferential direction of the blast furnace 1. Along with the hot air, pulverized coal, which will be described later, can also be blown into the furnace from the tuyere 2.
  • the annular pipe 3 is arranged to surround the lower part of the blast furnace 1. Multiple blowpipes 4 are installed on the annular pipe 3 at predetermined intervals in the circumferential direction. The annular pipe 3 supplies hot air sent from the hot stove to the blowpipes 4.
  • Each blowpipe 4 is connected to an annular pipe 3 and is also connected to a different tuyere 2.
  • the blowpipe 4 blows hot air sent from the annular pipe 3 into the blast furnace 1 through the tuyere 2.
  • the pulverized coal injection lance 5 is provided to inject pulverized coal into the furnace through the tuyere 2.
  • the pulverized coal injection lance 5 penetrates the wall of each blowpipe 4 and extends into the interior of each blowpipe 4.
  • the pulverized coal injected from the pulverized coal injection lance 5 into the blowpipe 4 is blown into the furnace through the tuyere 2 together with the hot air that flows into the blowpipe 4 from the annular pipe 3.
  • the rotating chute 6 rotates around an axis extending vertically, charging iron raw materials and coke in alternating layers.
  • Iron raw materials can be lump ore, sintered ore, pellets, unburned carbon-containing agglomerated ore, etc., but when reduced iron operation is performed, some of the iron raw materials can be replaced with reduced iron.
  • the iron raw materials may also contain reduction aids such as small coke.
  • the coke may also contain ferrocoke.
  • Forward tilting refers to a drive method that drives the rotating chute 6 from the furnace wall side toward the furnace center
  • reverse tilting refers to a drive method that drives the rotating chute 6 from the furnace center side toward the furnace wall side.
  • the tap hole 7 is located at the bottom of the blast furnace 1 and is used to tap the molten iron produced by reducing the iron raw materials. Multiple tap holes 7 are provided around the periphery of the furnace, allowing molten iron to be tapped continuously or intermittently.
  • the state before the reduced iron charging amount is changed is referred to as standard operation.
  • Standard operation refers to operation performed with operational specifications that are prerequisites for analysis.
  • the state after the reduced iron charging amount, blast specifications, and pulverized coal ratio are all changed from the standard operation values is referred to as second operation.
  • second operation The state after the reduced iron charging amount, blast specifications, and pulverized coal ratio are all changed from the standard operation values
  • first operation the state in which the reduced iron charging amount is changed from the standard operation values but the blast specifications and pulverized coal ratio are not changed from the standard operation values.
  • the first operation is provided to delay changes to the blast specifications and pulverized coal ratio.
  • Table 1 is a comparison table outlining the standard operation, the first operation, and the second operation.
  • blast furnace operation can be stabilized by optimizing the delay time for changing the blast parameters and pulverized coal ratio in response to a change in the amount of reduced iron charged, i.e., the length from the start of the first operation to the start of the second operation.
  • the delay time i.e., the length from the start of the first operation to the start of the second operation
  • the optimal delay time is a value obtained by simulation before the start of the second operation. Note that the start of the first operation refers to the time when the amount of reduced iron charged is changed from the value in the standard operation.
  • the start of the second operation refers to the time when one or both of the blast parameters and the pulverized coal ratio are changed from the values in the first operation.
  • Fig. 2 is a flowchart for explaining the method for operating a blast furnace according to the present embodiment.
  • the method for operating a blast furnace according to the present embodiment includes a standard operation, a first operation, and a second operation.
  • the process includes a parameter estimation step (S1), a change information acquisition step (S2), a repetition step (S3), and a minimum delay time acquisition step (S4). Each step will be explained in detail below.
  • the blast furnace operating method of this embodiment is an operating system in which the standard operation is switched to the first operation, and then the first operation is switched to the second operation. Therefore, before describing the contents of the specification estimation step, the definitions of the standard operation, the first operation, and the second operation will be described.
  • Reference operation refers to operation carried out with operating specifications that are prerequisites for analysis.
  • Reference operation may be operation that does not include reduced iron as an iron raw material, or operation that includes reduced iron. Furthermore, it is desirable that reference operation be operation during a stable operation period.
  • a stable operation period is a period in which blast furnace operation is stable, avoiding periods immediately before and after blast shutdowns, periods in which rapid increases in iron production occur, periods in which rapid increases or decreases in iron production occur, and periods in which blast specifications fluctuate greatly.
  • the blast specifications and pulverized coal ratio in the standard operation are applied to the first operation, which will be described later.
  • the pig iron production rate, molten iron temperature, and top gas temperature in the standard operation are used in the specification estimation step. These values can be kept approximately constant during the stable operation period.
  • the blast specifications and pulverized coal ratio, as well as the pig iron production rate, molten iron temperature, and top gas temperature at any point during the stable operation period can be used in the subsequent operation.
  • the blast specifications and pulverized coal ratio, as well as the pig iron production rate, molten iron temperature, and top gas temperature immediately after the standard operation is completed and the first operation is started are used in the subsequent operation. "Immediately before the start of the first operation" refers to, for example, the period up to 8 hours before the start of the first operation.
  • First operation refers to a blast furnace operation that has the same blast parameters and pulverized coal ratio as the reference operation but has a different amount of reduced iron charged than the reference operation.
  • the first operation may be an operation in which the amount of reduced iron charged is greater than that of the reference operation, or an operation in which the amount of reduced iron charged is less than that of the reference operation. An operation in which the amount of reduced iron charged is not substantially the same as that of the reference operation is considered to be the first operation.
  • the "air blast specifications” refer to the air blast volume, oxygen enrichment rate, and air blast moisture content. Therefore, when the charged amount of reduced iron in the standard operation is 0, the charged amount of reduced iron in the first operation is greater than 0. Furthermore, when the charged amount of reduced iron in the standard operation is k (k > 0), the charged amount of reduced iron in the first operation is greater than k or less than k.
  • the reduced iron blend ratio in the first and second operations is desirable to between 0.5% and 50% by mass.
  • the blending ratio in the first operation is 0.5% by mass or more, fluctuations in the amount of molten iron tapped and the temperature of the molten iron are likely to become large at the start of the first operation and the second operation. Therefore, the effects of the operating method disclosed herein are more favorably exhibited.
  • the blending ratio of reduced iron in the first operation may be 1% by mass or more, 5% by mass or more, or 10% by mass or more.
  • the reason why it is preferable to set the upper limit of the blending ratio in the first operation to 50 mass% is that if the amount of reduced iron is excessively high, the amount of oxygen to be reduced will decrease, resulting in less reducing gas in the operational design and disadvantages such as the inability to maintain the furnace top gas temperature.
  • the blending ratio of reduced iron in the first operation may also be set to 45 mass% or less, 40 mass% or less, or 30 mass% or less.
  • the higher the blend ratio of reduced iron in the first operation the greater the fluctuations in the iron production rate and molten iron temperature, which could lead to unstable blast furnace operation.
  • the blast furnace operation method disclosed herein allows for stable operation of the blast furnace while suppressing fluctuations in iron production rate and molten iron temperature. Therefore, the higher the blend ratio of reduced iron in the first operation, the more pronounced the effects of the blast furnace operation method disclosed herein are, which is preferable.
  • the "second operation” refers to an operation in which the amount of reduced iron charged is the same as in the first operation, but the blast specifications and pulverized coal ratio are different. Therefore, the example of the reduced iron blend ratio in the first operation described above can also be applied to the second operation.
  • the purpose of the "parameter estimation step” described below is to find the optimal blast specifications and pulverized coal ratio for this second operation.
  • the blast parameters and pulverized coal ratio for the second operation are estimated so that the iron production rate, molten iron temperature, and furnace top gas temperature for the second operation are the same as those for the reference operation.
  • the same as standard operation also includes “substantially the same.” For example, if the difference in pig iron production rate between standard operation and second operation is approximately ⁇ 100 (t/d), this is not considered an operational variation that requires operational action, and so can be considered “the same pig iron production rate.” If the difference in molten iron temperature between standard operation and second operation is approximately ⁇ 2°C, this is not considered an operational variation that requires operational action, and so can be considered “the same molten iron temperature.” If the difference in furnace top gas temperature between standard operation and second operation is approximately ⁇ 10 (°C), this is not considered an operational variation that requires operational action, and so can be considered "the same molten iron temperature.”
  • the parameter estimation step can be realized, for example, by analytical processing using a blast furnace mathematical model.
  • the processing for estimating the iron production rate, molten iron temperature, and furnace top gas temperature for the reference operation and the processing for estimating the blast parameters and pulverized coal ratio for the second operation are realized by analytical processing using the blast furnace mathematical model.
  • a blast furnace mathematical model (see, for example, Non-Patent Document 1) is a mathematical model that divides the internal region of a blast furnace into a mesh, and performs calculations by substituting preset setting conditions into calculation formulas for material balance, momentum balance, and energy balance to estimate state variables (output values), and comprehensively simulates the state inside the furnace.
  • This section explains a method for estimating the pig iron production rate, molten iron temperature, and top gas temperature for standard operation using a blast furnace mathematical model.
  • Setting conditions for standard operation such as the blast parameters, pulverized coal ratio (PC), reduced iron blending ratio, reduced iron consumption rate, blast moisture, and O/C, are input into the blast furnace mathematical model to estimate state variables.
  • the estimated state variables include at least the pig iron production rate, molten iron temperature, and top gas temperature.
  • the reduced iron blending ratio (mass%) refers to the ratio of the mass of reduced iron to the mass of iron raw materials.
  • the reduced iron consumption rate (kg/t) refers to the weight of reduced iron consumed to produce one ton of molten iron.
  • O/C refers to the weight ratio of the ore layer to the coke layer.
  • the estimated state variables may also include the theoretical combustion temperature at the tuyere tip, bosh gas volume, reducing agent ratio, coke ratio, PCI ratio, slag ratio, ⁇ CO, ⁇ H2, SLC, and furnace pressure loss.
  • the state variables are estimated in a steady state (operation time set to infinity).
  • This section explains how to obtain the blast parameters and pulverized coal ratio for the second operation using a blast furnace mathematical model.
  • the set conditions for the second operation such as the reduced iron blend ratio, reduced iron consumption unit, blast moisture, and O/C, are input into the blast furnace mathematical model, and the simulation conditions are set to "the same iron production rate, molten iron temperature, and furnace top gas temperature as in the standard operation.” This searches for the blast parameters and pulverized coal ratio that satisfy these conditions.
  • the iron production rate, molten iron temperature, and furnace top gas temperature for the second operation can also be estimated as state variables.
  • the output iron production rate, molten iron temperature, and furnace top gas temperature may be completely identical to the iron production rate, molten iron temperature, and furnace top gas temperature for the standard operation, or they may be substantially identical.
  • the range of substantial identicality can be set appropriately by adjusting the parameters of the blast furnace mathematical model. The meaning of "substantially identical" will not be repeated.
  • the operating conditions for the second operation such as blast moisture and O/C, may or may not be the same as those for the reference operation.
  • the parameter estimation step is realized by analytical processing using a blast furnace mathematical model, but the present disclosure is not limited to this, and it may also be realized by methods other than a blast furnace mathematical model.
  • the parameter estimation step may be performed by analytical processing using the RIST model.
  • the RIST model is known as a partial balance model based on thermodynamics, and its details are disclosed in, for example, Non-Patent Document 2, so a detailed explanation will be omitted.
  • information is acquired regarding changes over time in one or both of the molten iron temperature and the tapping rate when the second operation is carried out after a predetermined delay from switching from the standard operation to the first operation, based on the blast specifications and pulverized coal ratio estimated in the specification estimation step.
  • information regarding changes over time in both the molten iron temperature and the tapping rate is acquired.
  • the "predetermined time” is, for example, a candidate value for the optimal delay time, and is any value greater than 0.
  • the predetermined time is, for example, within a range of 1 hour to 10 hours.
  • the time point of switching from the standard operation to the first operation refers to the time point when the first operation starts.
  • the parameter estimation step by inputting the following conditions as settings: "The blast parameters, pulverized coal ratio, blast moisture, and O/C for the first operation are the same as those for the reference operation," "The reduced iron blend ratio for the first operation is the same as that for the second operation," and "A specified time (delay time),” it is possible to obtain, as a state variable, "information regarding the changes over time in either or both of the molten iron temperature and the amount of molten iron produced when switching to the second operation based on the blast parameters and pulverized coal ratio estimated in the parameter estimation step after a specified time has elapsed since the first operation.”
  • the change information acquisition step is realized by analytical processing using a blast furnace mathematical model, but the present disclosure is not limited to this, and methods other than the blast furnace mathematical model may also be used. For example, based on operational performance, information regarding changes over time when switching to second operation after a predetermined time has elapsed since first operation may be acquired.
  • the change information acquisition step is performed multiple times by changing the predetermined time, and "information regarding changes over time in the molten iron temperature and the tapping rate" is acquired for each "predetermined time.”
  • the repetition step estimates the results brought about by each of multiple candidate values for the optimal delay time.
  • the change information acquisition step is preferably repeated three or more times, four or more times, or five or more times, for example.
  • the predetermined time at which the change over time in either or both of the molten iron temperature and the tapping rate is minimized is determined as the optimum delay time from among the "predetermined times.” Whether or not it is "minimum” can be determined by comparing the molten iron temperature during standard operation (hereinafter also referred to as the molten iron temperature reference value) and the tapping rate during standard operation (hereinafter also referred to as the tapping rate reference value).
  • the molten iron temperature reference value and the tapping rate reference value will be collectively referred to as the "reference values.”
  • Determination method 1 Calculate the molten iron temperature and/or the amount of iron tapped from the start of the first operation until the operation stabilizes, and define the predetermined time in the second operation at which the maximum difference between the molten iron temperature and the reference value for the molten iron temperature or the maximum difference between the amount of iron tapped and the reference value for the amount of iron tapped is minimized as the "optimum delay time.”
  • "operation stabilizes” means that the amount of iron tapped and the molten iron temperature have recovered to the level of the reference operation, which means, for example, 24 hours after the start of the first operation.
  • Determination method 2 The difference between the molten iron temperature and/or the iron tapping rate and their respective reference values is determined from the start of the first operation until the operation stabilizes, and the predetermined time of the second operation at which the integral value of the difference between the molten iron temperature and the molten iron temperature reference value or the integral value of the difference between the iron tapping rate and the iron tapping rate reference value is minimized is defined as the "optimum delay time.”
  • Determination method 3 Calculate the average values of the molten iron temperature and the amount of iron tapped from the start of the first operation until the operation stabilizes, and determine the predetermined time of the second operation that minimizes the difference between the average molten iron temperature and the reference value for the molten iron temperature or the difference between the average amount of iron tapped and the reference value for the amount of iron tapped, as the "optimum delay time.”
  • Determination Method 1 Determination Method 1
  • Determination Method 2 Determination Method 3
  • Determination Method 3 can be selected as appropriate depending on the operational status. For example, even a sudden change in molten iron temperature or iron production rate, even over a short period of time, carries a high risk of destabilizing operations, so if such a phenomenon is observed, it is desirable to select Determination Method 1.
  • the blast furnace can be operated stably while suppressing fluctuations in the pig iron tapping rate and molten iron temperature.
  • starting the second operation after the optimal delay time has elapsed after switching from standard operation to first operation means matching the length of the first operation to the optimal delay time.
  • the length of the first operation and the optimal delay time need only be substantially the same.
  • the length of the first operation is within a range of, say, the optimal delay time ⁇ 30 minutes, the length of the first operation and the optimal delay time are considered to be substantially the same, and the blast furnace operating method characterized by "starting the second operation after the optimal delay time has elapsed after switching from standard operation to first operation" is considered to be being implemented. If the sensitivity of the pig iron tapping rate and molten iron temperature to the delay time is small, it is permissible to increase the difference between the optimal delay time and the actual delay time.
  • the optimal delay time may be determined based on the change in the molten iron temperature over time, or the optimal delay time may be determined based on the change in the amount of iron tapped over time.
  • the change in the molten iron temperature over time it is not necessary to acquire the change in the amount of iron tapped over time in the change information acquisition step.
  • the change in the amount of iron tapped over time it is not necessary to acquire the change in the molten iron temperature over time in the change information acquisition step.
  • the change information acquisition step information regarding changes over time in both the molten iron temperature and the amount of tapped iron may be acquired, and in the optimal delay time acquisition step, any one of the changes over time in the molten iron temperature and the amount of tapped iron may be used to determine the optimal delay time.
  • the one that is more sensitive to delay time may be used to determine the optimal delay time.
  • both the graph showing the change in the pig iron tapping rate over time shown in Figure 4A and the graph showing the change in the molten iron temperature over time shown in Figure 4B have a downwardly convex shape.
  • the graph showing the change in the molten iron temperature over time in Figure 4B has a steeper downward curve than the graph showing the change in the pig iron tapping rate over time in Figure 4A.
  • the sensitivity of the change in the molten iron temperature over time to the delay time is higher than that of the change in the pig iron tapping rate over time.
  • the blast furnace operation method described above there is only one opportunity to increase the amount of reduced iron charged during standard operation.
  • the amount of reduced iron charged is increased, but when switching from second operation to third operation, the amount of reduced iron charged is not increased.
  • there may be two or more opportunities to increase the amount of reduced iron charged For example, if the second operation satisfies the definition of standard operation, the second operation can be considered the standard operation, and the above-mentioned procedure can be performed again, thereby providing two opportunities to increase the amount of reduced iron charged. Naturally, the above-mentioned procedure can also be performed further. This makes it even easier to operate the blast furnace stably while suppressing fluctuations in the iron production rate and molten iron temperature. Specific examples of embodiments in which there are two or more opportunities to increase the amount of reduced iron charged are described below.
  • a third operation and a fourth operation may be further carried out.
  • the third operation is defined as an operation having the same blast specifications and pulverized coal ratio as the second operation, but with a larger amount of reduced iron charged than the second operation.
  • the fourth operation is defined as an operation having the same amount of reduced iron charged as the third operation, but with different blast specifications and pulverized coal ratio.
  • the method for operating a blast furnace includes: (S11) a second parameter estimation step of estimating blast parameters and a pulverized coal ratio in the fourth operation, which will result in the same iron tapping rate, molten iron temperature, and furnace top gas temperature as those in the second operation; (S12) a second change information acquisition step of acquiring information on changes over time in one or both of the molten iron temperature and the amount of tapped iron when a fourth operation is carried out with a predetermined delay after switching from the second operation to the third operation and based on the blast parameters and the pulverized coal ratio estimated in the second parameter estimation step; (S13) a second repeating step of performing the second change information acquisition step a plurality of times with different predetermined times; (S14) a second optimum delay time acquisition step of determining, based on the information acquired in the second repetition step, a predetermined time at which a change in the molten iron temperature or the amount of tapped iron over time is minimized as a second optimum delay time;
  • a second optimal delay time is calculated. Then, after switching from the second operation to the third operation, a delay of the second optimal delay time is applied, and the fourth operation is started based on the blast parameters and pulverized coal ratio estimated in the second parameter estimation step.
  • This increases the number of opportunities to increase the amount of reduced iron charged to two.
  • the fourth operation can be considered the standard operation, and the above procedure can be carried out again. By gradually increasing the amount of reduced iron charged, it becomes even easier to operate the blast furnace stably while suppressing fluctuations in the iron production rate and molten iron temperature.
  • a third operation and a fourth operation may be further carried out.
  • the third operation is defined as an operation having the same blast specifications and pulverized coal ratio as the second operation, but with a larger amount of reduced iron charged than the second operation.
  • the fourth operation is defined as an operation having the same amount of reduced iron charged as the third operation, but with different blast specifications and pulverized coal ratio.
  • the method for operating a blast furnace includes: (S21)
  • a second parameter estimation step may be included in which blast parameters and a pulverized coal ratio in the fourth operation, in which the iron tapping rate, molten iron temperature, and furnace top gas temperature in the fourth operation are the same as those in the second operation.
  • the configuration of the second parameter estimation step is substantially the same as the configuration of the parameter estimation step described above.
  • the optimal delay time applied to the fourth operation is the same as the optimal delay time applied to the second operation. In other words, the optimal delay time applied to the second operation is diverted to the fourth operation.
  • embodiment B Comparing embodiment A, which recalculates the optimal delay time, with embodiment B, which uses the optimal delay time for the second operation for the fourth operation, embodiment B omits the second change information acquisition step, the second repetition step, and the second optimal delay time acquisition step. Therefore, the calculation process in embodiment B is simpler than embodiment A.
  • Embodiment A is suitable for cases where the reduced iron blend ratio is increased unevenly.
  • the reduced iron blend ratio in the reference operation is 0%
  • the reduced iron blend ratio in the first and second operations is 10%
  • the reduced iron blend ratio in the third and fourth operations is 40%
  • Embodiment B is suitable for cases where the reduced iron blend ratio is increased uniformly. For example, if the reduced iron blend ratio in the reference operation is 0%, the reduced iron blend ratio in the first and second operations is 20%, and the reduced iron blend ratio in the third and fourth operations is 40%, it is preferable to apply the optimal delay time applied to the second operation to the fourth operation.
  • the parameter estimation step was carried out by carrying out an analytical process using a blast furnace mathematical model.
  • the set values given to the blast furnace mathematical model and the output state variables are shown in Table 2.
  • an operation in which reduced iron was not included in the iron raw material was set as the reference operation, and the blending ratio of reduced iron in the second operation was set to about 10 mass % (10.3 mass %).
  • blast specifications and pulverized coal ratio in the second operation were estimated to be blast volume: 5235 (Nm3/min), oxygen enrichment rate: 2.95 (%), and pulverized coal ratio (PC): 47.1 (t/hr).
  • the predetermined time for the "change information acquisition step” was set to three patterns: 4 hours, 6 hours, and 8 hours, and "information regarding changes over time in molten iron temperature and tapped iron volume” was acquired for each pattern.
  • Figure 3 shows the acquired results, and is a graph with time on the horizontal axis and tapped iron volume or molten iron temperature on the vertical axis. Note that the time when the first operation began is set to "0.”
  • FIG. 4A is a graph in which the horizontal axis represents the “switching timing for switching from the first operation to the second operation” and the vertical axis represents the “maximum difference from the reference value for iron production rate,” and corresponds to determination method 1.
  • FIG. 4B is a graph in which the horizontal axis represents the “switching timing from the first operation to the second operation” and the vertical axis represents the “maximum difference from the molten iron temperature reference value,” and corresponds to determination method 1.
  • FIG. 4A is a graph in which the horizontal axis represents the “switching timing for switching from the first operation to the second operation” and the vertical axis represents the “maximum difference from the molten iron temperature reference value,” and corresponds to determination method 1.
  • FIG. 5A is a graph in which the horizontal axis represents the “switching timing from the first operation to the second operation” and the vertical axis represents the “integral value of the difference from the reference value of the iron tapping rate,” and corresponds to determination method 2.
  • FIG. 5B is a graph in which the horizontal axis represents the “switching timing from the first operation to the second operation” and the vertical axis represents the “integral value of the difference from the reference value of the molten iron temperature,” and corresponds to determination method 2. The definitions of determination methods 1 and 2 will not be repeated.
  • markers in Figures 6A to 9B with the caption "X% ⁇ Y%" represent data for operations in which the reduced iron charging amount in the reference operation was X%, and the reduced iron charging amount in the first and second operations was Y%.
  • markers in Figures 6A to 9B with the caption "X% ⁇ Y%” represent data for operations in which the reduced iron charging amount in the reference operation was X%, and the reduced iron charging amount in the first and second operations was Y%.
  • a marker with the caption "0% ⁇ 5%” represents data for operations in which the reduced iron charging amount in the reference operation was 0%, and the reduced iron charging amount in the first and second operations was 5%.
  • Figures 6A and 6B are graphs with the horizontal axis representing the "timing for switching from the first operation to the second operation" and the vertical axis representing the "maximum difference from the reference value for iron production,” and correspond to determination method 1. Note that Figure 6A is a vertical expansion of Figure 6B, with the "0% ⁇ 50%" data series removed from the five data series shown in Figure 6B.
  • Figures 7A and 7B are graphs with the horizontal axis representing the "timing for switching from the first operation to the second operation" and the vertical axis representing the "maximum difference from the reference value for molten iron temperature,” and correspond to determination method 1. Note that Figure 7A is a vertical expansion of Figure 7B, with the "0% ⁇ 50%" data series removed from the five data series shown in Figure 7B.
  • Figures 8A and 8B are graphs with the horizontal axis representing the "timing for switching from the first operation to the second operation" and the vertical axis representing the "integral value of the difference from the reference value for iron production," and correspond to determination method 2. Note that Figure 8A is a vertical expansion of Figure 8B, with the "0% ⁇ 50%" data series removed from the five data series shown in Figure 8B.
  • Figures 9A and 9B are graphs with the horizontal axis representing the timing of switching from the first operation to the second operation and the vertical axis representing the integrated value of the difference from the reference molten iron temperature value, and correspond to determination method 2. Note that Figure 9A is a vertical expansion of Figure 9B, with the "0% ⁇ 50%" data series removed from the five data series shown in Figure 9B.

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  • Organic Chemistry (AREA)
  • Manufacture Of Iron (AREA)

Abstract

Un procédé de fonctionnement de haut fourneau selon un aspect de la présente divulgation comprend : une étape d'estimation de paramètre pour estimer des paramètres de souffle et un rapport de charbon pulvérisé dans une seconde opération, de telle sorte que la quantité de fer fondu produite, la température de fer fondu et la température de gaz de haut de four dans la seconde opération correspondent à celles dans une opération de référence ; une étape d'acquisition d'informations de changement pour acquérir des informations sur un changement temporel dans l'une ou les deux de la température de fer fondu et de la quantité de fer fondu produite lors de la réalisation de la seconde opération sur la base des paramètres de souffle et du rapport de charbon pulvérisé estimé dans l'étape d'estimation de paramètre avec un retard d'un temps prédéterminé après la commutation de l'opération de référence à la première opération ; une étape de répétition pour effectuer l'étape d'acquisition d'informations de changement une pluralité de fois tout en changeant le temps prédéterminé ; et une étape d'acquisition de temps de retard optimal pour déterminer, en tant que temps de retard optimal, un temps prédéterminé de telle sorte que le changement temporel de la température de fer fondu ou de la quantité de fer fondu produit est le plus petit, sur la base des informations acquises dans l'étape de répétition. Après commutation de l'opération de référence à la première opération, la seconde opération sur la base des paramètres de souffle et du rapport de charbon pulvérisé estimé dans l'étape d'estimation de paramètre est démarrée avec un retard du temps de retard optimal.
PCT/JP2024/040334 2024-02-27 2024-11-13 Procédé de fonctionnement de haut-fourneau Pending WO2025182165A1 (fr)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11286705A (ja) * 1998-04-03 1999-10-19 Sumitomo Metal Ind Ltd 高炉操業方法
JP2008111172A (ja) * 2006-10-31 2008-05-15 Jfe Steel Kk 高炉の操業方法
WO2014088031A1 (fr) * 2012-12-07 2014-06-12 新日鉄住金エンジニアリング株式会社 Procédé permettant de faire fonctionner un haut fourneau et procédé permettant de produire de la fonte brute liquide

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH11286705A (ja) * 1998-04-03 1999-10-19 Sumitomo Metal Ind Ltd 高炉操業方法
JP2008111172A (ja) * 2006-10-31 2008-05-15 Jfe Steel Kk 高炉の操業方法
WO2014088031A1 (fr) * 2012-12-07 2014-06-12 新日鉄住金エンジニアリング株式会社 Procédé permettant de faire fonctionner un haut fourneau et procédé permettant de produire de la fonte brute liquide

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