JP4291764B2 - Blast furnace operation method - Google Patents

Description

The present invention relates to a method for operating a blast furnace in which a copper stave cooler is provided in a furnace body.

Conventionally, in blast furnace operation, a phenomenon called blow-through has occurred in the furnace.
As a method for preventing this blow-through, for example, Patent Document 1 discloses that a blow-out has occurred empirically from the combined conditions of the pressure data of a plurality of stages of the blast furnace shaft portion, the blast furnace interior entrance level detection data, and the blast furnace gas temperature data. Is set, and when the reference value based on this condition is exceeded, a method of reducing the amount of hot air blown into the blast furnace by a predetermined width is disclosed.

JP-A-4-173908

However, the above-described method is suitable for a blast furnace in which a cast iron stave cooler (hereinafter also simply referred to as a cast iron stave) used as a furnace body cooling device is provided in the furnace body, and the gas temperature data in the furnace is This is a measurement method using a thermocouple thermometer (hereinafter also simply referred to as a thermometer) provided on a cast iron stave.
In recent years, in order to extend the life of the blast furnace, in the case of a blast furnace in which a copper stave cooler (hereinafter also simply referred to as a copper stave) is provided in the furnace body instead of the conventionally used cast iron stave, the copper stave is made of cast iron. Since the cooling capacity is higher than that of the stave, the fluctuation cycle of the furnace body temperature measured with a thermometer provided on the copper stave is extremely small, and the temperature within a predetermined time (for example, 30 minutes) is reduced. The method of detecting a place where the average value exceeds a preset temperature has a problem that the operation status of the blast furnace cannot be accurately evaluated.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a blast furnace operating method capable of stably operating a blast furnace in which a copper stave cooler is provided in the furnace body.

As a result of various studies to solve the above-mentioned problems, the present inventor did not suddenly generate a blast furnace blow-through, but a small amount of high-temperature furnace gas was locally generated several times in the lump body in the furnace. After the rise, a large amount of high-temperature furnace gas is generated by raising the lump body, so it is possible to predict the occurrence of blow-by by detecting the number of times this small amount of high-temperature furnace gas rises. The knowledge that it is possible was obtained.
The present invention has been made on the basis of the above knowledge, and the feature thereof is that in a method of operating a blast furnace in which a copper stave cooler is provided in the furnace body,
Measure the furnace temperature with a thermometer installed on the copper stave cooler, determine the frequency at which this measured furnace temperature exceeds the temperature indicating the precursor of blow- by, determine whether this detection frequency exceeds the control value, When the detection frequency exceeds the control value, the operating condition of the blast furnace is adjusted either or both of the charging position of the charge into the blast furnace and the amount of hot air blown into the blast furnace. To change the frequency at which the measured furnace temperature exceeds the temperature indicating the precursor of the blow-through to the control value or less.

Here, the management value, a frequency greater than the temperature that indicates the sign of atrium measured furnace temperature degree, which indicates that it is safe range not yet occurred blow, a precursor to blow the measured furnace body temperature When the frequency exceeding the indicated temperature exceeds the control value, there is a high possibility that blow-through will occur, and when the frequency is equal to or less than the control value, it means that the possibility of blow-through is low.

The operation method of the blast furnace of the present invention uses a frequency at which the furnace temperature measured by a thermometer exceeds a temperature indicating a sign of blow-through (hereinafter, also simply referred to as a detection frequency), and whether or not this frequency exceeds a control value. Therefore, for example, even when the fluctuation range of the furnace body temperature is extremely small, it is possible to reliably capture the sign that leads to blow-through. Therefore, the blast furnace provided with the copper stave cooler having a high cooling capacity can be stably operated while preventing the blow-through.

Here, when determining whether or not the detection frequency by each thermometer provided in the height direction of the blast furnace exceeds the control value, if the control value is smaller than the lower side of the blast furnace, It is possible to determine the precursors to reach each location in the blast furnace and contribute to further stable operation of the blast furnace.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory diagram of a blast furnace to which a method for operating a blast furnace according to an embodiment of the present invention is applied, and FIGS. It is explanatory drawing which shows the change of the measurement temperature of a meter.

As shown in FIG. 1, the operation method of a blast furnace according to an embodiment of the present invention stabilizes the operation of a blast furnace 12 in which a furnace 10 is provided with a copper stave cooler (hereinafter also simply referred to as a copper stave) 11. It is a suitable method to do. The copper stave cooler 11 constitutes a part of the furnace body 10 together with the iron shell 13 and the refractory 14 of the blast furnace 12.
First, after describing the blast furnace 12 to which the blast furnace operating method according to an embodiment of the present invention is applied, the blast furnace operating method will be described.

As shown in FIG. 1, copper stave coolers 11 are arranged in a plurality of stages in the height direction of the furnace body 10 above the tuyere 15 of the blast furnace 12. Each copper stave cooler 11 has a copper stave body 16 manufactured by, for example, a mold or rolling, and a plurality of water passages (not shown) for flowing cooling water are formed therein. is there.
The stave body 16 is provided with a plurality of thermocouple thermometers (hereinafter also simply referred to as thermocouples) 17, and the detection end 18 of each thermocouple 17 can be formed on the furnace inner surface side of the stave body 16. By making it as close as possible (for example, a position of 15 mm), the temperature change of the furnace body 10 can be reliably detected.
The measurement data of each thermocouple 17 is input and recorded in a control unit (not shown).

Next, a method for operating a blast furnace according to an embodiment of the present invention will be described with reference to FIG.
During operation of the blast furnace 12, the temperature of the furnace body 10 is measured by the detection end 18 of each thermocouple 17 installed in the stave body 16, and the measured furnace body temperature is input to the control unit. The measurement furnace body temperature can be used by averaging the temperatures of all the thermocouples 17 provided in each copper stave cooler 11, or the temperature of each thermocouple 17 can be used individually.

Since the measurement furnace body temperature differs for each region in the height direction of the blast furnace 12, that is, for each copper stave cooler 11, its transition for each copper stave cooler 11 as shown in FIGS. Is recorded. 2A to 2C show changes in measured temperature of the thermocouple 17 installed on the stave body 16 of each copper stave cooler 11 installed on the upper side, the center, and the lower side of the shaft portion 19 of the blast furnace 12, respectively. Is shown.

Next, the frequency at which the measured furnace temperature exceeds the preset reference temperature is determined.
This reference temperature is a temperature indicating a sign of blow-through, and needs to be a temperature that is not affected by the water temperature used for cooling. For example, the reference temperature is 40 ° C. or higher depending on the installation position of each copper stave cooler 11. It is preferable to set within a range of about 150 ° C. or less.
Further, the frequency of the measurement furnace body temperature exceeding the reference temperature is measured within a preset time (for example, 30 minutes), and it is determined whether or not the measured frequency exceeds the control value. This control value is preferably determined on the basis of past actual operation data (rule of thumb) of the blast furnace, and is a numerical value within a safe range where no blow-through occurs yet.

Here, the determination method will be described with reference to FIGS.
Although the temperature transition shown in FIGS. 2 (A) to 2 (C) is locally increased, it is difficult to catch a sign of blow-through as compared with the case where a conventional cast iron stave cooler is used. . This is because the measured temperature data for 30 minutes is averaged. In the copper stave cooler 11 having good heat conductivity, even if the temperature rises according to the state of the furnace, it takes a short time. In addition, since the temperature of the stave body 16 decreases, in the average temperature data for 30 minutes, the temperature indicating the precursor of the blow-through is averaged by other temperatures.

Therefore, the measured temperature data is recorded as temperature data every minute without averaging every 30 minutes, and the frequency of temperatures exceeding the reference temperature within 30 minutes is integrated by the control unit. If this accumulated detection frequency exceeds the control value, the possibility of blow-through in the blast furnace 12 is increased, and measures are taken to prevent blow-through.

In addition, since the in-furnace condition of the blast furnace 12 changes according to each place in the furnace of the blast furnace 12, the control value is set smaller than the lower side of the blast furnace 12 by the control unit. This is because the measured furnace body temperature exceeding the reference temperature detected on the upper side of the blast furnace 12 is more easily connected to the blow-through than the lower side of the blast furnace 12. For example, when the lower management value of the shaft portion 19 is 10, the central management value is set to 3, and the upper management value is set to 1.
In this way, the blast furnace 12 can be operated more stably by using a plurality of thermocouples 17 provided in the height direction of the blast furnace 12.

The operation change of the blast furnace 12 can also be determined by combining the management value of the measurement furnace body temperature and the management value of the measurement furnace pressure.
In this case, a plurality of pressure gauges (not shown) are installed in the height direction of the blast furnace 12, and the frequency at which the pressure in the measurement furnace measured by the pressure gauge exceeds a preset threshold is defined as the measurement furnace temperature. Similarly, integration is performed.

Based on the above result, when the detection frequency exceeding the reference temperature of the furnace body temperature measured by each thermocouple 17 exceeds the control value, the operating condition of the blast furnace 12 is changed.
This change in the operating conditions of the blast furnace 12 is achieved by changing the charging position of the charge (for example, ore or coke) into the blast furnace 12 to a position immediately above a place where blow-through is likely to occur, or the amount of hot air blown into the blast furnace 12 Is reduced by a preset value within a range in which there is no problem in operation of the blast furnace 12.
In this way, by adjusting the charging position of the charge to the blast furnace 12 and / or the amount of hot air blown into the blast furnace 12, the frequency at which the measured furnace body temperature exceeds the reference temperature is set to the control value or less to prevent blow-through. Enables stable blast furnace operation.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included. For example, in the above-described embodiment, the operation condition of the blast furnace was changed by adjusting the charging position of the charge to the blast furnace and the amount of hot air blown into the blast furnace. It is of course possible to adjust other operating parameters that contribute to prevention.

It is explanatory drawing of the blast furnace to which the operating method of the blast furnace which concerns on one embodiment of this invention is applied. (A)-(C) is explanatory drawing which shows the change of the measurement temperature of each thermometer provided in the height direction of the same blast furnace, respectively.

Explanation of symbols

10: furnace body, 11: copper stave cooler, 12: blast furnace, 13: iron skin, 14: refractory, 15: tuyere, 16: stave body, 17: thermocouple thermometer, 18: detection end, 19: Shaft part

Claims (2)

In the operation method of the blast furnace where the copper stave cooler is provided in the furnace body,
Measure the furnace temperature with a thermometer installed on the copper stave cooler, determine the frequency at which this measured furnace temperature exceeds the temperature indicating the precursor of blow- by, determine whether this detection frequency exceeds the control value, When the detection frequency exceeds the control value, the operating condition of the blast furnace is adjusted either or both of the charging position of the charge into the blast furnace and the amount of hot air blown into the blast furnace. change the blast furnace method operation, characterized by the frequency at which the measured furnace body temperature exceeds the temperature that indicates the sign of the blow below the control value. The blast furnace operating method according to claim 1, wherein a plurality of the thermometers are provided in a height direction of the blast furnace, and when performing the determination in the height direction of the blast furnace, the control value is set above the lower side of the blast furnace. A method of operating a blast furnace characterized by reducing the size of the blast furnace.

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