Method, control device, and control program for blast furnace operation

Abstract

To stabilize the operation of a blast furnace based on a powder ratio of a blast furnace raw material to be charged into the blast furnace.SOLUTION: A method for blast furnace operation includes: measuring a particle size of a blast furnace raw material to be charged into a blast furnace 10 from a top of the blast furnace a plurality of times; obtaining a change rate of a powder rate of the blast furnace raw material based on the measured particle size of the blast furnace raw material; and changing blast furnace operation conditions of the blast furnace 10 when the obtained change rate of the powder rate of the blast furnace raw material is equal to or more than a threshold value.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a blast furnace operation method, a blast furnace operation control device, and a blast furnace operation control program. [Background technology]

[0002] There is a ventilation control device that periodically measures the particle size of blast furnace raw materials charged into a blast furnace and controls the amount of air blown into the blast furnace according to the measured particle size of the blast furnace raw materials (see, for example, Patent Document 1).

[0003] There is also a blast furnace operation method in which the particle size of coke charged into the blast furnace as a blast furnace raw material is periodically measured, and the amount of air blown into the blast furnace is controlled when the change in the coke fineness calculated from the measured coke particle size is equal to or greater than a threshold value (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2021-503042 A [Patent Document 2] International Publication No. 2021 / 085221 Summary of the Invention [Problem to be solved by the invention]

[0005] In the blast furnace operation method disclosed in Patent Document 2, as described above, when the change in the fineness ratio of coke as a blast furnace raw material charged into the blast furnace is equal to or greater than a threshold value, the amount of air blown into the blast furnace is controlled to stabilize blast furnace operation.

[0006] However, in this type of blast furnace operation method, there is room for further improvement in order to stabilize the blast furnace operation.

[0007] The technology disclosed in the present application aims to stabilize blast furnace operation based on the fineness ratio of blast furnace raw materials charged into the blast furnace. [Means for solving the problem]

[0008] The blast furnace operation method of the first embodiment measures the particle size of blast furnace raw materials charged into a blast furnace from the top of the furnace multiple times, calculates a rate of change in the fineness ratio of the blast furnace raw materials based on the measured particle size of the blast furnace raw materials, and changes the blast furnace operation conditions of the blast furnace if the calculated rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value.

[0009] According to the above aspect, the particle size of the blast furnace raw materials charged into the blast furnace from the furnace top is measured multiple times, and the rate of change in the fineness ratio of the blast furnace raw materials is calculated based on the measured particle size of the blast furnace raw materials. Then, when the rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value, the blast furnace operating conditions of the blast furnace are changed.

[0010] Here, for example, even if the amount of change (difference) in the fineness ratio of the blast furnace raw materials is less than the threshold value, if the rate of change in the fineness ratio of the blast furnace raw materials is large, the impact on the blast furnace operation may be large. Conversely, even if the amount of change in the fineness ratio of the blast furnace raw materials is equal to or greater than the threshold value, if the rate of change in the fineness ratio of the blast furnace raw materials is small, the impact on the blast furnace operation may be small.

[0011] Therefore, in this embodiment, as described above, when the rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value, the blast furnace operation conditions are changed. As a result, in this embodiment, the blast furnace operation can be stabilized compared to the method of changing the blast furnace operation conditions when the rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value.

[0012] A blast furnace operation method according to a second aspect is the blast furnace operation method according to the first aspect, wherein the blast furnace operation conditions include a flow velocity of in-furnace gas rising within the blast furnace, and when the determined rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value, the flow velocity of the in-furnace gas is increased.

[0013] According to the above aspect, the blast furnace operation conditions include the flow velocity of the furnace gas rising inside the blast furnace, and when the rate of change in the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, the flow velocity of the furnace gas is increased.

[0014] This allows the powder of the blast furnace raw materials charged into the blast furnace from the furnace top to be discharged from the furnace top to the outside of the blast furnace. This prevents the deterioration of the gas permeability inside the blast furnace due to an increase in the amount of powder inside the blast furnace, thereby stabilizing the operation of the blast furnace.

[0015] A blast furnace operation method according to a third aspect is the blast furnace operation method according to the first aspect, wherein the blast furnace operation conditions include a heat flow ratio within the blast furnace, and when the determined rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value, the heat flow ratio is reduced.

[0016] According to the above aspect, the blast furnace operation conditions include a heat flow ratio in the blast furnace, and when the rate of change in the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, the heat flow ratio is reduced.

[0017] This makes it possible to suppress the temperature drop in the blast furnace caused by an increase in the amount of fines in the blast furnace, thereby suppressing the delay in the reduction of the blast furnace raw materials in the blast furnace, and thus stabilizing the operation of the blast furnace.

[0018] A blast furnace operation method according to a fourth aspect is the blast furnace operation method according to the first aspect, wherein the blast furnace operation conditions include a flow velocity of furnace gas rising within the blast furnace and a heat flow ratio within the blast furnace, and when the determined rate of change of the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value, the flow velocity of the furnace gas is increased, and then an in-furnace permeability index indicating the permeability within the blast furnace is determined, and when the determined in-furnace permeability index is equal to or greater than a threshold value, the heat flow ratio is decreased.

[0019] According to the above aspect, the blast furnace operation conditions include the flow rate of the furnace gas rising in the blast furnace and the heat flow ratio in the blast furnace. Then, when the obtained rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value, the flow rate of the furnace gas is increased. Then, an in-furnace permeability index indicating the permeability in the blast furnace is obtained, and when the obtained in-furnace permeability index is equal to or greater than a threshold value, the heat flow ratio is decreased.

[0020] In other words, in this embodiment, when the rate of change of the fineness ratio of the obtained blast furnace raw material is equal to or greater than a threshold value, if the gas permeability in the furnace is not improved even if the flow rate of the gas in the furnace is increased, the heat flow ratio in the blast furnace is decreased. This makes it possible to further stabilize the blast furnace operation.

[0021] A blast furnace operating method according to a fifth aspect is the blast furnace operating method according to the second or fourth aspect, wherein the flow velocity of the gas in the furnace is increased by reducing a pressure at a top of the blast furnace.

[0022] According to the above-mentioned embodiment, the flow rate of the gas in the furnace is increased by lowering the pressure at the top of the blast furnace. This allows the powder of the blast furnace raw material charged into the blast furnace from the top to be discharged from the top to the outside of the blast furnace. This prevents the decrease in the gas permeability of the blast furnace caused by the increase in the amount of powder in the blast furnace, thereby stabilizing the operation of the blast furnace.

[0023] A blast furnace operation method according to a sixth aspect is the blast furnace operation method according to the third or fourth aspect, wherein the heat flow ratio is lowered by increasing an oxygen enrichment rate of oxygen added to air blown into the blast furnace.

[0024] According to the above aspect, the heat flow ratio in the blast furnace is reduced by increasing the oxygen enrichment rate of oxygen (pure oxygen) added to the air blown into the blast furnace. This makes it possible to suppress a decrease in temperature in the blast furnace due to an increase in the amount of fines in the blast furnace. Therefore, the reduction delay of the blast furnace raw materials in the blast furnace is suppressed, and the blast furnace operation can be stabilized.

[0025] The blast furnace operation control device of the seventh aspect includes a control unit that executes processing to measure the particle size of blast furnace raw materials charged into a blast furnace from the top of the furnace multiple times, calculate a rate of change in the fineness ratio of the blast furnace raw materials based on the measured particle size of the blast furnace raw materials, and change the blast furnace operation conditions of the blast furnace if the calculated rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value.

[0026] The blast furnace operation control program according to the eighth embodiment causes a computer to execute a process of measuring the particle size of blast furnace raw materials charged into a blast furnace from the top of the furnace multiple times, calculating a rate of change in the fineness ratio of the blast furnace raw materials based on the measured particle size of the blast furnace raw materials, and changing the blast furnace operation conditions of the blast furnace if the calculated rate of change in the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value. Effect of the Invention

[0027] According to the technology disclosed in the present application, it is possible to stabilize blast furnace operation based on the fineness ratio of blast furnace raw materials charged into the blast furnace. [Brief description of the drawings]

[0028] [Figure 1] 1 is a vertical cross-sectional view showing a blast furnace to which a blast furnace operation method according to an embodiment is applied. [Diagram 2] FIG. 2 is a functional block diagram of a blast furnace operation control device and a particle size measuring device according to an embodiment. [Diagram 3] FIG. 2 is a hardware configuration diagram of a blast furnace operation control device according to an embodiment. [Figure 4] 2 is a flowchart showing an example of a blast furnace operation control process according to an embodiment. [Diagram 5] 1A and 1B are graphs showing experimental results for comparative examples in a blast furnace operation experiment, in which (A) shows the relationship between the number of operation days and the fineness rate of iron ore and the rate of change of said fineness rate, (B) shows the relationship between the number of operation days and the flow velocity of the gas in the furnace and the rate of change of said flow velocity, (C) shows the relationship between the number of operation days and the amount of solution loss carbon, and (D) shows the relationship between the number of operation days and the amount of iron produced. [Figure 6] 1 is a graph showing the experimental results of Example 1 in a blast furnace operation experiment, in which (A) shows the relationship between the number of operation days and the fineness rate of iron ore and the rate of change of the fineness rate, (B) shows the relationship between the number of operation days and the flow velocity of the gas in the furnace and the rate of change of the flow velocity, (C) shows the relationship between the number of operation days and the heat flow ratio and the rate of change of the heat flow ratio, (D) shows the relationship between the number of operation days and the amount of solution loss carbon, and (E) shows the relationship between the number of operation days and the amount of iron produced. [Figure 7]13 is a graph showing the experimental results of Example 2 in a blast furnace operation experiment, in which (A) shows the relationship between the number of operation days and the fineness rate of iron ore and the rate of change of the fineness rate, (B) shows the relationship between the number of operation days and the flow velocity of the gas in the furnace and the rate of change of the flow velocity, (C) shows the relationship between the number of operation days and the heat flow ratio and the rate of change of the heat flow ratio, (D) shows the relationship between the number of operation days and the amount of solution loss carbon, and (E) shows the relationship between the number of operation days and the amount of iron produced. [Figure 8] 13 is a graph showing the experimental results of Example 3 in a blast furnace operation experiment, in which (A) shows the relationship between the number of operation days and the fineness rate of iron ore and the rate of change of the fineness rate, (B) shows the relationship between the number of operation days and the flow velocity of gas in the furnace and the rate of change of the flow velocity, (C) shows the relationship between the number of operation days and the heat flow ratio and the rate of change of the heat flow ratio, (D) shows the relationship between the number of operation days and the amount of solution loss carbon, (E) shows the relationship between the number of operation days and the amount of iron produced, and (F) shows the relationship between the number of operation days and the furnace permeability index. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] Hereinafter, one embodiment will be described with reference to the drawings.

[0030] (blast furnace) 1 shows a blast furnace 10 to which the blast furnace operating method according to the present embodiment is applied. A raw material charging device 20 is provided at the top of the blast furnace 10. Iron ore, coke, and the like as blast furnace raw materials are transported to the raw material charging device 20 by a transport device 22. The raw material charging device 20 alternately charges the iron ore and coke as blast furnace raw materials into the blast furnace 10. As a result, coke layers and iron ore layers are alternately deposited in the blast furnace 10.

[0031] Hot air, auxiliary fuel, and the like are blown into the blast furnace 10 through tuyere 12 provided at the bottom of the blast furnace 10. This causes the auxiliary fuel and coke to burn, generating furnace gas (reducing gas) G that rises inside the blast furnace 10. The iron ore in the iron ore layer piled up inside the blast furnace 10 is heated and reduced by this furnace gas G as it descends. The iron ore melts as it descends and is discharged as pig iron from a tap hole (not shown) provided on the side wall of the furnace bottom.

[0032] The in-furnace gas G that rises in the blast furnace 10 is discharged as exhaust gas to the top pressure power plant 28 through the exhaust duct 24. The top pressure power plant 28 generates electricity by rotating a turbine (not shown) using the exhaust gas discharged from the blast furnace 10.

[0033] The exhaust duct 24 is provided with a damper 26 that controls the effective cross-sectional area of ​​the exhaust duct 24 and adjusts the amount of exhaust gas discharged to the top pressure power generation unit 28. The blast furnace 10 is controlled by a blast furnace operation control device 40 (see FIG. 2) described later.

[0034] (Particle size measuring device) 2, in this embodiment, the particle sizes of iron ore and coke as blast furnace raw materials charged into a blast furnace 10 are periodically measured by a particle size measuring device 30. The particle sizes of the blast furnace raw materials measured by the particle size measuring device 30 are, for example, time-series data.

[0035] The method of measuring the particle sizes of iron ore and coke using the particle size measuring device 30 is similar. Therefore, hereinafter, a case of measuring the particle size of iron ore (sintered ore) as an example of a blast furnace raw material will be described.

[0036] Iron ore is transported from a raw material tank (not shown) to a raw material charging device 20 provided at the top of the blast furnace 10 by a transport device 22 such as a belt conveyor. The particle size of the iron ore is measured by a particle size measuring device 30 provided on the transport path of the transport device 22.

[0037] The particle size measuring device 30 includes an imaging unit 32 and an image processing unit 34. The imaging unit 32 is, for example, a digital camera that images iron ore, and is installed above the transport path of the transport device 22 or the like. This imaging unit 32 images the iron ore transported by the transport device 22 or the like from above, and outputs the captured image data to the image processing unit 34.

[0038] The image processing unit 34 is configured by, for example, a computer or the like. This image processing unit 34 performs image processing (image analysis) on the image data output from the imaging unit 32, and obtains particle size information (including particle size and particle size distribution) of iron ore within a predetermined range (predetermined mass). Then, the image processing unit 34 outputs the obtained particle size information of the iron ore to the blast furnace operation control device 40.

[0039] (Outline of the blast furnace operation control device) The blast furnace operation control device 40 controls the overall operation of the blast furnace 10. Further, the blast furnace operation control device 40 obtains the change rate of the powder ratio of the blast furnace raw materials based on the particle size of the blast furnace raw materials measured by the particle size measuring device 30. Then, when the obtained change rate of the powder ratio of the blast furnace raw materials is equal to or greater than the threshold value, the blast furnace operation control device 40 changes the blast furnace operation conditions of the blast furnace 10.

[0040] (Hardware configuration of the blast furnace operation control device) Next, the hardware configuration of the blast furnace operation control device 40 will be described.

[0041] The blast furnace operation control device 40 is realized by, for example, a computer 70 shown in FIG. 3. The computer 70 includes a CPU (Central Processing Unit) 72, a memory 74 as a temporary storage area, and a non-volatile storage unit 76. The computer 70 also includes an input / output device 78. These CPU 72, memory 74, storage unit 76, and input / output device 78 are connected to each other via a bus 79. Note that the CPU 72 is an example of a control unit and a processor.

[0042] The storage unit 76 is realized by, for example, a hard disk drive (HDD), a solid state drive (SSD), a flash memory, etc. The storage unit 76 as a recording medium stores in advance a blast furnace operation control program for causing the computer 70 to function as the blast furnace operation control device 40. The storage unit 76 also has a storage area for storing various data.

[0043] The input / output device 78 includes a pointing device such as a mouse, a keyboard, and a display unit, and is used to input various types of information.

[0044] The CPU 72 reads out the blast furnace operation control program from the storage unit 76, develops it in the memory 74, and sequentially executes each process of the blast furnace operation control program. As a result, the computer 70 that executes the blast furnace operation control program functions as the blast furnace operation control device 40.

[0045] (Functions of blast furnace operation control device) Next, the function of the blast furnace operation control device 40 will be described.

[0046] As shown in Fig. 2, the blast furnace operation control device 40 realizes various functions by using the above hardware resources when executing the above-mentioned blast furnace operation control program. Specifically, the blast furnace operation control device 40 functionally includes a fineness ratio calculation unit 42, a fineness ratio change rate calculation unit 44, and a blast furnace operation condition change unit 46.

[0047] (Dust content calculation section) The fineness ratio calculation unit 42 calculates the fineness ratio (%) of the blast furnace raw material based on the particle size (particle size information) of the blast furnace raw material measured by the above-mentioned particle size measuring device 30. Specifically, it calculates the ratio of the mass of the fineness of the blast furnace raw material (fined ore or fine coke) to a predetermined mass of the blast furnace raw material (iron ore or coke).

[0048] In addition, the powder of the blast furnace raw material is, as an example, a blast furnace raw material having a diameter (particle size) of 5 mm or less, but the standard diameter of the powder of the blast furnace raw material can be changed as appropriate.

[0049] Based on the particle size (particle size information) of the blast furnace raw materials regularly measured by the particle size measuring device 30, the powder ratio calculation unit 42 calculates the powder ratio of the blast furnace raw materials at each measurement time, and stores the calculated powder ratio at each measurement time in a predetermined storage area of the storage unit 76 as time-series data.

[0050] Note that the powder ratio calculation unit 42 may calculate the average particle size of the blast furnace raw materials from the particle size information of the blast furnace raw materials measured by the particle size measuring device 30, and calculate the powder ratio of the blast furnace raw materials based on the correlation between the average particle size and the powder ratio of the blast furnace raw materials created in advance.

[0051] Further, the powder ratio calculation unit 42 may calculate the powder ratio of the blast furnace raw materials based on the average value of the particle sizes (particle size information) of a plurality of blast furnace raw materials measured within a predetermined time period.

[0052] (Powder ratio change rate calculation unit) Based on the powder ratio of the blast furnace raw materials calculated by the powder ratio calculation unit 42, the powder ratio change rate calculation unit 44 calculates the change rate of the powder ratio. Specifically, the powder ratio change rate calculation unit 44 calculates the change rate R of the powder ratio by the following formula (1). [Number] However, Powder ratio at measurement time T1: The powder ratio obtained from the particle size information of the blast furnace raw materials measured at measurement time T1 Powder ratio at measurement time T2: The powder ratio obtained from the particle size information of the blast furnace raw materials measured at measurement time T2 (T1 < T2) That is.

[0053] Note that the change rate R of the powder ratio of the blast furnace raw materials may be calculated based on the powder ratios of the same type of blast furnace raw materials (iron ore or coke) measured at different measurement times T1 and T2. Further, the change rate R of the powder ratio of the blast furnace raw materials may be calculated based on the average value of the powder ratios of iron ore and coke measured at the measurement time (measurement time zone) T2 and the average value of the powder ratios of iron ore and coke measured at the measurement time (measurement time zone) T1.

[0054] (Blast Furnace Operation Conditions Change Department) The blast furnace operation condition change unit 46 changes the blast furnace operation conditions of the blast furnace 10 when the change rate R of the fineness ratio of the blast furnace raw material calculated by the fineness ratio change rate calculation unit 44 is equal to or greater than a threshold value. Examples of the blast furnace operation conditions include the flow rate of the in-furnace gas G rising in the blast furnace 10 and the heat flow ratio in the blast furnace 10.

[0055] Specifically, when the rate of change R of the fineness ratio of the blast furnace raw materials calculated by the fineness ratio change rate calculation unit 44 is equal to or greater than a threshold value, the blast furnace operation condition change unit 46 increases the flow velocity of the in-furnace gas G rising in the blast furnace 10. As a result, as shown in FIG. 1, the powder (fine powder) of the blast furnace raw materials charged in the blast furnace 10 is easily discharged to the outside of the blast furnace 10 together with the in-furnace gas G through the exhaust duct 24. Therefore, the decrease in the gas permeability in the blast furnace 10 due to the increase in the amount of powder in the blast furnace 10 is suppressed.

[0056] The flow velocity of the in-furnace gas G is adjusted by increasing or decreasing the pressure at the furnace top 10A of the blast furnace 10 depending on the opening degree of the damper 26 of the exhaust duct 24 connected to the furnace top 10A of the blast furnace 10. Specifically, when the opening degree of the damper 26 is increased, the pressure at the furnace top 10A of the blast furnace 10 decreases, and the flow velocity of the in-furnace gas G rising in the blast furnace 10 increases. On the other hand, when the opening degree of the damper 26 is decreased, the pressure at the furnace top 10A of the blast furnace 10 increases, and the flow velocity of the in-furnace gas G rising in the blast furnace 10 decreases.

[0057] The threshold value of the rate of change R of the fineness ratio of the blast furnace raw material is appropriately set based on the operating performance of the blast furnace 10, etc.

[0058] In addition, the blast furnace operation condition change unit 46, after increasing the flow rate of the furnace gas G, obtains an in-furnace permeability index indicating the permeability in the blast furnace 10, and when the obtained in-furnace permeability index is equal to or greater than a threshold value, reduces the heat flow ratio in the blast furnace 10. This suppresses a temperature drop associated with an increase in the amount of fines in the blast furnace 10. As a result, a delay in the reduction of the blast furnace raw materials in the blast furnace 10 is suppressed.

[0059] An example of the furnace permeability index is the ventilation resistance index K 1 and is calculated from the following formula (2).

number

[0060] Moreover, the heat flow ratio in the blast furnace 10 is calculated by the following formula (3). Heat flow ratio = heat capacity of solid / heat capacity of furnace gas (3) The solid in formula (3) refers to blast furnace raw materials including iron ore, coke, and the like.

[0061] The heat flow ratio in the blast furnace 10 is adjusted by increasing or decreasing the oxygen enrichment rate of oxygen (pure oxygen) added to the air (hot air) blown into the blast furnace 10 from the tuyere 12 .

[0062] The oxygen enrichment rate is an index showing the oxygen concentration enriched from the oxygen concentration in air (21%). When the oxygen enrichment rate is increased, the heat capacity of the furnace gas G decreases and the heat flow ratio increases. On the other hand, when the oxygen enrichment rate is decreased, the heat capacity of the furnace gas G increases and the heat flow ratio decreases. This oxygen enrichment rate is adjusted by the amount of oxygen (pure oxygen amount) and the amount of air added to the air (hot air) blown into the blast furnace 10 from the tuyere 12.

[0063] (Blast furnace operation method) Next, an example of a blast furnace operation method will be described while explaining the operation of the blast furnace operation control device 40.

[0064] During operation of the blast furnace 10, the blast furnace operation control device 40 calculates the fineness ratio of the blast furnace raw materials at each measurement time based on the particle size (particle size information) of the blast furnace raw materials measured periodically by the particle size measuring device 30, and stores the calculated fineness ratio for each measurement time in a specified memory area of ​​the memory unit 76 as time-series data.

[0065] In addition, the blast furnace operation control device 40 periodically executes the blast furnace operation process shown in FIG. 4. The blast furnace operation process is an example of a blast furnace operation method. In the following, as an example, a case will be described in which the blast furnace operation control device 40 controls the blast furnace operation conditions based on the particle size of the iron ore.

[0066] As shown in FIG. 4, first, in step S10, the CPU 72 calculates the rate of change R of the fineness ratio (formula (1)) based on the fineness ratio (fineness ratio information) of the iron ore measured by the particle size measuring device 30 at different measurement times T1 and T2.

[0067] The measurement time T2 is, for example, the measurement time immediately before the blast furnace operation process is performed, and the measurement time T1 is, for example, the measurement time a predetermined time before the measurement time T2.

[0068] Next, in step S12, the CPU 72 determines whether the change rate R of the fineness of the iron ore is equal to or greater than a predetermined threshold. If the CPU 72 determines that the change rate R of the fineness of the iron ore is less than the threshold, the process ends. On the other hand, if the CPU 72 determines that the change rate R of the fineness of the iron ore is equal to or greater than the threshold, the process proceeds to step S14.

[0069] Next, in step S14, the CPU 72 increases the flow rate of the in-furnace gas G (see FIG. 1) rising in the blast furnace 10. Specifically, as shown in FIG. 1, the CPU 72 increases the opening degree of the damper 26 of the exhaust duct 24 to lower the air pressure at the furnace top 10A of the blast furnace 10.

[0070] This increases the flow rate of the in-furnace gas G, making it easier for the iron ore powder (fine powder) charged into the blast furnace 10 to be discharged together with the exhaust gas to the outside of the blast furnace 10 through the exhaust duct 24. Therefore, the decrease in the gas permeability inside the blast furnace 10 is suppressed.

[0071] Next, in step S16, the CPU 72 calculates the furnace internal permeability index (airflow resistance index K 1 ) and judges whether the calculated furnace permeability index is equal to or greater than a predetermined threshold. If the furnace permeability index is less than the threshold, the CPU 72 ends the process. On the other hand, if the furnace permeability index is equal to or greater than the threshold, the CPU 72 proceeds to step S18.

[0072] Next, in step S18, the CPU 72 lowers the heat flow ratio in the blast furnace 10 and ends the process. Specifically, the CPU 72 adjusts the amount of oxygen (pure oxygen amount) and the amount of air added to the air blown into the blast furnace 10 from the tuyere 12, and increases the oxygen enrichment rate. This lowers the heat flow ratio in the blast furnace 10, and suppresses a decrease in temperature in the blast furnace 10. Therefore, a delay in the reduction of iron ore in the blast furnace 10 is suppressed.

[0073] (effect) Next, the effects of this embodiment will be described.

[0074] According to this embodiment, as described above, the particle size of the blast furnace raw materials charged into the blast furnace 10 from the furnace top is periodically measured, and the rate of change R of the fineness ratio of the blast furnace raw materials is calculated based on the measured particle size of the blast furnace raw materials. Then, when the rate of change R of the fineness ratio of the blast furnace raw materials is equal to or greater than a threshold value, the blast furnace operation conditions of the blast furnace 10 are changed.

[0075] Here, for example, when changing the blast furnace operating conditions based on the change amount (difference) of the powder ratio of the blast furnace raw materials, even if the change amount of the powder ratio is less than the threshold value, if the change rate R of the powder ratio of the blast furnace raw materials is large, the influence on the blast furnace operation may become large. Conversely, when changing the blast furnace operating conditions based on the change amount of the powder ratio of the blast furnace raw materials, even if the change amount of the powder ratio is equal to or greater than the threshold value, if the change rate R of the powder ratio of the blast furnace raw materials is small, the influence on the blast furnace operation may become small.

[0076] Therefore, in the present embodiment, as described above, when the change rate R of the powder ratio of the blast furnace raw materials is equal to or greater than the threshold value, the blast furnace operating conditions are changed. Thereby, in the present embodiment, compared with the method of changing the blast furnace operating conditions when the change amount of the powder ratio of the blast furnace raw materials is equal to or greater than the threshold value, the stabilization of the blast furnace operation can be achieved.

[0077] Further, in the present embodiment, when the change rate R of the powder ratio of the blast furnace raw materials is equal to or greater than the threshold value, as the blast furnace operating condition, the flow rate of the in-furnace gas G is increased. Thereby, the powder of the blast furnace raw materials charged into the blast furnace 10 from the furnace top can be discharged outside the blast furnace 10 through the exhaust duct 24 from the furnace top portion 10A. Therefore, since the decrease in the air permeability inside the blast furnace 10 accompanying the increase in the powder amount inside the blast furnace 10 is suppressed, the stabilization of the blast furnace operation can be achieved.

[0078] Further, in the present embodiment, by increasing the flow rate of the in-furnace gas G, for example, the stabilization of the blast furnace operation can be achieved without increasing the amount of coke used per ton of hot metal (coke ratio). Therefore, an increase in material cost can be suppressed.

[0079] Here, even if the flow rate of the in-furnace gas G is increased, it is assumed that due to various factors, the air permeability inside the blast furnace 10 is not improved. Therefore, in the present embodiment, after increasing the flow rate of the in-furnace gas G, the in-furnace air permeability index (air permeability resistance index K 1 ) inside the blast furnace 10 is obtained, and when the obtained in-furnace air permeability index is equal to or greater than the threshold value, the heat flow ratio is decreased.

[0080] This suppresses a decrease in temperature in the blast furnace 10 that is caused by an increase in the amount of fines in the blast furnace 10. Therefore, a delay in the reduction of the blast furnace raw materials in the blast furnace 10 is suppressed, so that the blast furnace operation can be further stabilized.

[0081] In addition, in this embodiment, by adjusting the above-mentioned oxygen enrichment rate, it is possible to lower the heat flow ratio while maintaining a constant amount of oxygen blown into the blast furnace 10. Therefore, it is possible to suppress a decrease in the amount of pig iron produced.

[0082] (Blast furnace operation experiment) Next, the blast furnace operation experiment will be explained.

[0083] In this experiment, as an example, a furnace with a volume of 4000 m 3 In a blast furnace of this class, the particle size of the iron ore charged into the blast furnace was periodically measured, and the rate of change R of the fineness of the iron ore was calculated based on the measured particle size of the iron ore.

[0084] Then, as a blast furnace operation according to the embodiment, when the rate of change R of the iron ore fineness ratio was equal to or greater than a threshold value, the flow rate of the gas inside the blast furnace and the heat flow ratio as blast furnace operation conditions were changed, and the effect on the amount of solution carbon loss and the amount of iron produced was verified.

[0085] In addition, as a comparative example of blast furnace operation, when the rate of change R of the iron ore fineness ratio was equal to or greater than a threshold value, the effect on the amount of solution carbon loss and the amount of iron produced was examined without changing the blast furnace operating conditions.

[0086] The particle size of the iron ore charged into the blast furnace was measured every 8 hours (3 times per day). The amount of coke used per ton of molten iron (coke ratio) was kept constant. When calculating the fineness of the iron ore, iron ore with a diameter of 5 mm or less was considered to be fine ore, for example. The threshold value of the rate of change R of the fineness of the iron ore was set to 20%, for example. The furnace permeability index (airflow resistance index K 1 ) is set to 2.25 as an example.

[0087] (Comparative Example) First, Fig. 5(A), Fig. 5(B), Fig. 5(C), Fig. 5(D), and Fig. 5(E) show blast furnace operation data according to a comparative example.

[0088] The horizontal axis in Figures 5(A) to 5(E) indicates the number of days the blast furnace was in operation, and the vertical axis in Figures 5(A) to 5(E) is as follows: Figure 5(A): The vertical axis on the left shows the fineness rate (%) of iron ore (sintered ore) corresponding to the solid line graph, and the vertical axis on the right shows the change rate (%) of the fineness rate of iron ore corresponding to the dotted line graph. FIG. 5(B): The vertical axis on the left side shows the flow velocity (m / s) of the furnace gas corresponding to the solid line graph, and the vertical axis on the right side shows the rate of change (%) of the furnace gas flow velocity corresponding to the dotted line graph. FIG. 5(C): The left vertical axis indicates the heat flow ratio (-) corresponding to the solid line graph, and the right vertical axis indicates the rate of change (%) of the heat flow ratio corresponding to the dotted line graph. FIG. 5(D): The vertical axis on the left side shows the amount of solution loss carbon (kg / t) corresponding to the solid line graph. Figure 5(E): The vertical axis on the left shows the iron production rate (t / d) corresponding to the solid line graph.

[0089] 5(A), in the blast furnace operation according to the comparative example, the fineness of the iron ore increased from about 7.7% to about 9.9% from the first day to the second day. In addition, the rate of change R of the fineness of the iron ore from the first day to the second day was about 28%, which was greater than the threshold value (20%).

[0090] In the blast furnace operation according to the comparative example, as shown in Figs. 5(B) and 5(C), the flow velocity and heat flow ratio of the in-furnace gas G are not forcibly changed.

[0091] As shown in FIG. 5(D), in the blast furnace operation according to the comparative example, the amount of solution loss carbon, which is an index showing the reduction state in the blast furnace, increased rapidly on the third day. This increase in the amount of solution loss carbon means a delay in the reduction of iron ore. In addition, as shown in FIG. 5(E), the amount of pig iron produced decreased rapidly on the fourth day. This is thought to be due to the effect of reducing the amount of blast air (air + oxygen enrichment) caused by the deterioration of the permeability in the furnace due to the increase in the amount of fine iron ore in the blast furnace, which led to a drop in the temperature in the blast furnace and a delay in the reduction of the blast furnace raw materials.

[0092] Example 1 On the other hand, Figures 6(A), 6(B), 6(C), 6(D), and 6(E) show blast furnace operation data according to Example 1. The horizontal and vertical axes in Figures 6(A) to 6(E) are the same as the horizontal and vertical axes in Figures 5(A) to 5(E).

[0093] 6(A), in the blast furnace operation according to Example 1, the fineness of the iron ore increased from about 8.3% to about 10.7% from the first day to the second day. In addition, the change rate R of the fineness of the iron ore from the first day to the second day was about 30%, which was greater than the threshold value (20%).

[0094] Therefore, in the blast furnace operation according to Example 1, the flow rate of the furnace gas G was increased by about 3.8% on the third day. In the blast furnace operation according to Example 1, as shown in FIG. 6(C), the heat flow ratio was not forcibly changed.

[0095] As shown in Figures 6(D) and 6(E), in the blast furnace operation according to Example 1, no sudden increase or decrease was observed in the amount of solution loss carbon and the amount of pig iron produced after the second day. From this, it can be seen that by increasing the flow rate of the gas G in the furnace, the increase in the amount of fines in the blast furnace and the decrease in gas permeability were suppressed, and the blast furnace operation was stabilized.

[0096] Example 2 Next, Figures 7(A), 7(B), 7(C), 7(D), and 7(E) show blast furnace operation data according to Example 2. The horizontal and vertical axes in Figures 7(A) to 7(E) are the same as the horizontal and vertical axes in Figures 5(A) to 5(E).

[0097] 7(A), in the blast furnace operation according to Example 2, the fineness of the iron ore increased from about 6.8% to about 8.9% from the first day to the second day. In addition, the rate of change R of the fineness of the iron ore from the first day to the second day was about 30%, which was greater than the threshold value (20%).

[0098] Therefore, in the blast furnace operation according to Example 2, the heat flow ratio in the blast furnace was reduced by about 3.9% on the third day. In the blast furnace operation according to Example 2, the flow rate of the gas G in the furnace was not forcibly changed as shown in FIG. 7(B).

[0099] 7(D) and 7(E), in the blast furnace operation according to Example 2, no sudden increase or decrease was observed in the amount of solution loss carbon and the amount of pig iron produced after the second day. This shows that by lowering the heat flow ratio in the blast furnace, the temperature drop in the blast furnace and the reduction delay were suppressed, and the blast furnace operation was stabilized.

[0100] Example 3 Next, Fig. 8(A), Fig. 8(B), Fig. 8(C), Fig. 8(D), Fig. 8(E), and Fig. 8(F) show blast furnace operation data according to Example 3. The horizontal and vertical axes in Fig. 8(A) to Fig. 8(E) are the same as the horizontal and vertical axes in Fig. 5(A) to Fig. 5(E). The horizontal axis in Fig. 8(E) shows the number of days the blast furnace was in operation, and the vertical axis on the left shows the furnace permeability index (furnace permeability resistance index K 1 )

[0101] 8(A), in the blast furnace operation according to Example 3, the fineness of the iron ore increased from about 8.2% to about 9.9% from the first day to the second day. In addition, the rate of change R of the fineness of the iron ore from the first day to the second day was about 21%, which was greater than the threshold value (20%).

[0102] Therefore, in the blast furnace operation according to Example 3, the flow rate of the furnace gas G was increased by about 2.6% on the third day. However, as shown in FIG. 8(F), the furnace gas permeability index (air permeability resistance index K 1 ) increased rapidly and exceeded the threshold value (2.25).

[0103] Therefore, in the blast furnace operation according to Example 3, the heat flow ratio in the blast furnace was reduced by about 2.4% on the fourth day.

[0104] 8(D) and 8(E), in the blast furnace operation according to Example 3, the amount of pig iron produced decreased slightly after the second day, but no rapid increase or decrease was observed in the amount of solution loss carbon and the amount of pig iron produced. From this, it can be seen that the temperature drop in the blast furnace and the reduction delay were suppressed by increasing the flow rate of the in-furnace gas G and then decreasing the heat flow ratio in the blast furnace, and the blast furnace operation was stabilized.

[0105] (Modification) Next, a modification of the above embodiment will be described.

[0106] In the above embodiment, the fineness ratio of the blast furnace raw materials is measured periodically by the particle size measuring device 30. However, the measurement of the fineness ratio of the blast furnace raw materials by the particle size measuring device 30 is not limited to being periodically performed. The measurement of the fineness ratio of the blast furnace raw materials by the particle size measuring device 30 may be performed multiple times so as to be able to calculate the correction coefficient for the coke cold strength. For example, the manager of the blast furnace 10 may operate the particle size measuring device 30 on an irregular basis (as needed) to measure the fineness ratio of the blast furnace raw materials multiple times.

[0107] In addition, the different measurement times T1 and T2 when determining the rate of change R of the fineness of the blast furnace raw material are appropriately changed taking into account the blast furnace operation history, etc.

[0108] In the above embodiment, the change in the blast furnace operation conditions can be changed as appropriate. For example, when the rate of change in the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, at least one of the flow rate and the heat flow ratio of the furnace gas G may be changed.

[0109] In addition, the blast furnace operation conditions are not limited to the flow rate and heat flow ratio of the furnace gas G, but may be, for example, the charging conditions of the blast furnace raw materials to the blast furnace 10, the amount of coke used per ton of molten iron (coke ratio), or the amount of air (hot air volume) blown into the blast furnace 10 from the tuyere 12.

[0110] In addition, in the above embodiment, the control unit (processor) includes a general-purpose processor (e.g., CPU: Central Processing Unit, etc.) or a dedicated processor (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0111] Furthermore, the processing flow in the blast furnace operation control device 40 described in the above embodiment is also one example, and unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged, within the scope that does not deviate from the gist of the technology disclosed in the present application.

[0112] In the above embodiment, the programs are installed in a ROM or storage, but the present invention is not limited to this. The programs according to the above embodiment may be provided in a form recorded in a computer-readable storage medium. For example, the programs according to the above embodiment may be provided in a form recorded in an optical disc such as a CD (Compact Disc)-ROM or a DVD (Digital Versatile Disc)-ROM, or in a form recorded in a semiconductor memory such as a USB (Universal Serial Bus) memory or a memory card. The programs according to the above embodiment may be obtained from an external device via a communication I / F.

[0113] Although one embodiment of the technology disclosed in the present application has been described above, the technology disclosed in the present application is not limited to the above embodiment. In addition, the above embodiment and various modified examples may be used in appropriate combination, and the technology disclosed in the present application may be embodied in various forms without departing from the gist of the technology. [Explanation of symbols]

[0114] 10 blast furnace 10A furnace top 40 Blast furnace operation control device

Claims

1. The grain size of the raw materials charged into the blast furnace from the top is measured multiple times. Calculating a rate of change in the fineness of the blast furnace raw material based on the measured particle size of the blast furnace raw material; When the obtained rate of change in the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, the blast furnace operation conditions of the blast furnace are changed. Blast furnace operating methods.

2. The blast furnace operation conditions include a flow rate of furnace gas rising in the blast furnace, When the obtained rate of change in the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, the flow velocity of the gas in the furnace is increased. The method for operating a blast furnace according to claim 1.

3. The blast furnace operation conditions include a heat flow ratio in the blast furnace, When the obtained rate of change in the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, the heat flow ratio is reduced. The method for operating a blast furnace according to claim 1.

4. The blast furnace operation conditions include a flow rate of furnace gas rising in the blast furnace and a heat flow ratio in the blast furnace, When the change rate of the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, the flow rate of the gas in the furnace is increased, An in-furnace permeability index indicating the permeability in the blast furnace is obtained, and when the obtained in-furnace permeability index is equal to or greater than a threshold value, the heat flow ratio is reduced. The method for operating a blast furnace according to claim 1.

5. The flow rate of the gas in the furnace is increased by reducing the pressure at the top of the blast furnace. The blast furnace operating method according to claim 2 or claim 4.

6. The heat flow ratio is reduced by increasing the oxygen enrichment rate of oxygen added to the air blown into the blast furnace. The blast furnace operating method according to claim 3 or claim 4.

7. The grain size of the raw materials charged into the blast furnace from the top is measured multiple times. Calculating a rate of change in the fineness of the blast furnace raw material based on the measured particle size of the blast furnace raw material; When the obtained rate of change in the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, the blast furnace operation conditions of the blast furnace are changed. A blast furnace operation control device including a control unit that executes processing.

8. The grain size of the raw materials charged into the blast furnace from the top is measured multiple times. Calculating a rate of change in the fineness of the blast furnace raw material based on the measured particle size of the blast furnace raw material; When the obtained rate of change in the fineness ratio of the blast furnace raw material is equal to or greater than a threshold value, the blast furnace operation conditions of the blast furnace are changed. A blast furnace operation control program that causes a computer to execute processing.

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