JP2006188768A - Method for preventing worn-out of brick in blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing the worn-out of brick in a blast furnace with which the worn-out of the side wall brick at a furnace bottom by beforehand grasping the state of starting the wearing of the side wall brick at the furnace bottom. <P>SOLUTION: At least two sets of thermometers T<SB>0</SB>, T<SB>1</SB>are embedded at different positions in the thickness direction of the furnace bottom brick 12 in the blast furnace 10, and a percolating heat quantity Q of the furnace bottom brick 12 is obtained from the measured values of the thermometers T<SB>0</SB>, T<SB>1</SB>and the percolating heat quantity Q is controlled in a prescribed range. Further, at least two sets of the thermometers T<SB>0</SB>, T<SB>1</SB>are embedded at different positions in the thickness direction of the furnace bottom brick 12 in the blast furnace 10, and a temperature gradient ΔT from the temperature difference between the measured values of the thermometers T<SB>0</SB>, T<SB>1</SB>, is obtained and this temperature gradient ΔT is controlled in a prescribed range. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a blast furnace brick wear prevention method for preventing wear of a refractory brick lined in a blast furnace.

The blast furnace operates for a long period of time to reduce iron ore and produce hot metal. During operation of this blast furnace, the bottom wall bricks are worn, and if the degree of wear increases, the life of the furnace is affected. In order to manage the wear of the bottom wall brick during operation, a thermometer is embedded in each brick, and the wear state of the bottom wall brick is grasped from the measured temperature.
However, this temperature may change suddenly and exceed the control value, and once the control value is exceeded, the blast furnace operation is forced to stop due to abnormal wear of the bottom wall bricks. was there.
Therefore, as a method of avoiding abnormal wear of the furnace bottom side wall bricks and suspension of blast furnace operation, Patent Document 1 includes an overflow type cooling water receiver projecting from the bottom wall of the furnace bottom, and by opening and closing control of the valve. A furnace bottom cooling method for cooling the furnace bottom side wall by controlling the amount of cooling water is disclosed. As a result, the amount of heat removed from the bottom wall of the furnace bottom can be controlled only by controlling the opening and closing of the cooling water receiving valve, so that the blast furnace operation can be performed stably.

Further, in Patent Document 2, the center part and the peripheral part of the cooling pipe embedded in the bottom surface of the furnace are divided into blocks, and each of them is cooled independently according to the temperature of the bottom brick. A cooling method has been proposed. As a result, the cooling water temperature can be controlled independently for each zone to be cooled, so that the blast furnace operation can be performed in a stable state while protecting the furnace bottom brick without cooling the furnace bottom more than necessary. .
And in patent document 3, after calculating the thickness of the air layer of the amorphous refractory accompanying the expansion and contraction of the iron skin based on the measured values of the temperature of the bottom wall of the blast furnace and the cooling water temperature. A method of cooling the bottom brick, which estimates the temperature of the bottom brick and repairs the air layer based on the estimated temperature, is disclosed. Thereby, cooling of the iron skin of a furnace bottom side wall part can be performed efficiently, damage prevention of the brick of a furnace bottom side wall part, and reduction of the heat loss from a furnace bottom side wall part can be aimed at.

JP-A-3-274208 JP-A-6-158132 JP-A-8-127810

However, in the method described in Patent Document 1, when the temperature of the furnace bottom brick is excessively decreased, a gap is generated between the furnace bottom side wall brick and the iron skin due to the shrinkage of the furnace bottom brick, and the iron skin is removed. Even if it cools from the outside, a furnace bottom side wall brick cannot be cooled, but the cooling capacity with respect to a furnace bottom side wall brick falls remarkably. As a result, the cooling of the bottom wall brick cannot be controlled, and the bottom wall brick becomes severely damaged, and the blast furnace operation cannot be performed in a stable state.
Further, in the method described in Patent Document 2, since the solidified layer is already generated abnormally on the bottom of the furnace and the convection of the hot metal is generated, strong and weak cooling is performed according to the portion of the furnace bottom, resulting in the convection of the hot metal. There is a problem that local wear of the bottom wall brick is caused, and the temperature rise of the bottom wall brick is generated, and the blast furnace operation is stopped or the production is reduced to solve this. In addition, this method does not control the temperature of the furnace bottom brick so that no gap is generated between the furnace bottom side wall brick and the iron skin. The bottom wall bricks are worn out.
And in the method of patent document 3, in performing cooling of a furnace bottom side wall part, since the cooling water temperature measured value and furnace bottom side wall temperature of a furnace bottom side wall part are used, the cooling water temperature rise of a furnace bottom side wall part is used. When the temperature of the bottom wall of the furnace bottom increases, the wear of the brick at the bottom of the furnace has already progressed, and it is impossible to prevent the wear of the brick at the bottom of the furnace wall due to the annular flow of hot metal.
The present invention has been made in view of such circumstances, and provides a method for preventing wear of a blast furnace brick by previously grasping a state in which the furnace bottom side wall brick starts to be worn and suppressing wear of the bottom wall brick in advance. Objective.

The method for preventing wear of a blast furnace brick according to the first aspect of the present invention comprises burying at least two thermometers at different positions in the thickness direction in the bottom brick of the blast furnace, and calculating the bottom of the furnace from the measured value of the thermometer. When determining the heat flow through the brick and controlling the heat flow through within a predetermined range, the predetermined range of the heat flow through is 2500 to 3400 Kcal / m ² · hr . Conventionally, when the heat flow through the bottom of the furnace brick has decreased excessively, shrinkage has occurred in the bottom brick, and a gap has formed between the bottom wall brick and the iron skin. The bottom wall brick could not be cooled, and the cooling capacity for the bottom wall brick was significantly reduced. However, by controlling the heat flow through the bottom brick within a specified range, it is possible to control the temperature of the bottom brick appropriately and prevent the formation of voids between the bottom brick and the iron shell. Since it can be done, the bottom wall brick can be cooled by cooling the iron shell from the outside.
Here, since the predetermined range of the heat flow through is 2500 to 3400 K cal / m ² · hr , the furnace bottom brick can be easily cooled within an appropriate range.

In the method for preventing wear of a blast furnace brick according to the second aspect of the present invention, at least two thermometers are buried in different positions in the thickness direction in the bottom brick of the blast furnace, and the temperature of the measured value of each thermometer is embedded. A temperature gradient ΔT is obtained from the difference, and the temperature gradient ΔT is controlled within a predetermined range. In this way, by controlling the temperature gradient ΔT obtained from the measured values of each thermometer of the furnace bottom brick within a predetermined range, the temperature control of the furnace bottom brick can be appropriately performed, and the bottom wall brick and iron Since the generation | occurrence | production of the space | gap between skins can be prevented beforehand, a furnace bottom side wall brick can be cooled by cooling an iron skin from the outside. Further, since the control is performed with the temperature gradient ΔT obtained from the measured value of the thermometer, the control is easy.
Here, in the method for preventing wear of a blast furnace brick according to the second invention, the predetermined range of the temperature gradient ΔT is preferably 1 to 3.5 ° C./cm. The upper limit value and the lower limit value of the predetermined range are numbers substantially corresponding to the upper limit value and the lower limit value of the heat flow through 2500 to 3400 K cal / m ² · hr, respectively, but depending on the thermal conductivity of the furnace bottom brick. Therefore, it can be managed in a narrower range. Further, since the temperature gradient ΔT is a temperature difference per 1 cm, the control range during the blast furnace operation can be easily obtained from the predetermined range even when the position of the thermometer is changed.

In the method for preventing blast furnace brick wear according to the first and second inventions, it is preferable to increase or decrease the amount of coke relative to the amount of ore in the blast furnace in order to control the obtained numerical value within a predetermined range. Here, when the obtained numerical value approaches the upper limit value of the predetermined range, the temperature in the furnace is higher than usual, so the amount of coke relative to the amount of ore is reduced from the current level. On the other hand, when the obtained numerical value approaches the lower limit value of the predetermined range, the temperature in the furnace is lower than usual, so the amount of coke relative to the amount of ore is increased from the current state. Thereby, the inside of a blast furnace can be maintained at an appropriate temperature.
In the blast furnace brick wear prevention method according to the first and second inventions, it is preferable to increase or decrease the combustion temperature before the tuyere in order to control the obtained numerical value within a predetermined range. Here, when the obtained numerical value approaches the upper limit value of the predetermined range, the temperature in the furnace is higher than usual, so the combustion temperature before the tuyere is reduced from the current state. Further, when the obtained numerical value approaches the lower limit value of the predetermined range, the temperature in the furnace is lower than usual, so the combustion temperature before the tuyere is increased from the current state. Thus, by increasing or decreasing the combustion temperature before the tuyere, the temperature in the furnace can be raised or lowered, and the inside of the furnace can be maintained at an appropriate temperature.

In the method for preventing wear of blast furnace bricks according to the first and second inventions, when the obtained numerical value falls below the lower limit of the predetermined range, the bottom wall brick and iron integrated with the bottom brick when the bottom brick shrinks It is preferable to fill the gap formed between the skin with a filler having a higher thermal conductivity than air. Thus, when the obtained numerical value falls below the lower limit value of the predetermined range, it means that the heat passing through the furnace bottom brick is reduced, and the furnace bottom brick contracts. At this time, the bottom wall brick united with the bottom brick moves toward the center of the blast furnace, and a gap is formed between the bottom wall brick and the iron skin. The heat conduction between the bottom wall brick and the iron skin can be maintained. Thereby, a furnace bottom side wall brick can be cooled appropriately by cooling an iron skin from the outside.
In the method for preventing blast furnace brick wear according to the first and second inventions, the filler is preferably one or more of mortar, carbon paste, heavy oil, and CO ₂ gas. Thereby, the influence of the clearance gap produced between a furnace bottom side wall brick and an iron skin with an inexpensive material can be suppressed.
In the method for preventing wear of blast furnace bricks according to the first and second inventions, when the obtained numerical value is below the lower limit value of the predetermined range, the cooling water temperature of the iron skin outside the furnace bottom side wall brick integrated with the furnace bottom brick It is preferable to reduce the current value from the current level. Here, when the obtained numerical value falls below the lower limit value of the predetermined range, a gap is generated or is about to occur between the furnace bottom side wall brick and the iron skin. At this time, by lowering the cooling water temperature of the iron skin from the current level, the iron skin is contracted with respect to the brick at the bottom of the furnace bottom, and the generation of the gap can be suppressed or the generated gap can be eliminated.

In the method for preventing wear of blast furnace bricks according to claims 1 to 6, since the numerical value obtained from the measured value of the thermometer embedded in the furnace bottom brick is controlled within a predetermined range, the temperature control of the furnace bottom brick is appropriately performed. It can be carried out. Thereby, generation | occurrence | production of the space | gap between a furnace bottom side wall brick and an iron skin can be prevented beforehand, or the heat insulation by a space | gap can be prevented, Therefore A furnace bottom side wall brick can be cooled by cooling an iron skin. Therefore, since the cooling of the furnace bottom side wall brick can be controlled, it is possible to suppress and further prevent wear that has conventionally occurred in the furnace bottom side wall brick.
Thus, the lifetime of a furnace bottom brick and a furnace bottom side wall brick can be made longer than before by suppressing the abrasion by the hot metal of a furnace bottom side wall brick. In addition, since it is possible to suppress the wear of the bricks at the bottom of the furnace bottom, it is economical because it is possible to prevent the blast furnace operation from being suspended, to reduce production, and the like.

In particular, in the method for preventing wear of a blast furnace brick according to claim 1, since the range of control of the through-flow heat quantity is set, the workability of blast furnace operation is good.

In the method for preventing wear of blast furnace brick according to claim 2, since the amount of coke is increased or decreased with respect to the amount of ore according to the obtained numerical value, the inside of the furnace of the blast furnace is maintained at an appropriate temperature to prevent wear of the blast furnace brick. it can.
In the method for preventing wear of blast furnace brick according to claim 3, because the combustion temperature before the tuyere is increased or decreased according to the obtained numerical value, the inside of the furnace of the blast furnace is maintained at an appropriate temperature in a short time, Blast furnace brick wear can be prevented.
In the method for preventing wear of a blast furnace brick according to claim 4, since it is possible to easily grasp when the bottom brick is cooled and contracted based on the obtained numerical value, for example, whether or not a gap has occurred as in the conventional case. It is no longer necessary to perform the gap filling operation which is intended to be performed without grasping the case where no gap is generated, so that a wasteful operation can be omitted. Further, since the heat conduction between the furnace bottom side wall brick and the iron skin can be maintained by the filler, the furnace bottom side wall brick can be appropriately cooled when the iron skin is cooled.

In the method for preventing wear of a blast furnace brick according to claim 5, it is economical because an influence of a gap generated between the bottom wall brick and the iron skin can be suppressed with an inexpensive material.
In the method for preventing wear of a blast furnace brick according to claim 6, the iron shell is contracted with respect to the furnace bottom side wall brick by lowering the cooling water temperature of the iron skin from the current state, thereby suppressing the generation of a gap or the generated gap. Disappearance is possible. Thereby, it becomes possible to perform cooling required for a furnace bottom side wall brick, the temperature of the raised bottom wall brick can be reduced, and the wear of a furnace bottom side wall brick can be suppressed.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
FIG. 1 is an explanatory diagram of a blast furnace to which the method for preventing wear of a blast furnace brick according to an embodiment of the present invention is applied, and FIGS. 2 (A) to (C) are furnace bottom bricks according to the first embodiment, respectively. Explanatory view showing the change in the temperature difference between the through-flow heat amount and the measured value of the thermometer, the explanatory view showing the change of ore / coke, the explanatory view of the temperature change of the furnace bottom side wall brick, FIG. 3 (A), (B) Explanatory drawing which shows the change of the temperature difference of the through-flow heat amount of the furnace bottom brick and the measured value of the thermometer according to the second embodiment, the explanatory drawing of the change of the bottom board cooling water amount, and FIGS. Explanatory drawing which shows the change of the temperature difference of the flow rate of the bottom brick and the measured value of the thermometer according to the third embodiment, the explanatory diagram of the temperature change of the bottom brick at the time of using the filler, Explanatory drawing of temperature change of furnace bottom side wall brick at the time of use, FIGS. 5 (A) to (C) are respectively related to the fourth embodiment. Explanatory view showing a change in temperature difference between the measured value of the cross-flow heat and a thermometer furnace bottom bricks, explanatory view showing a change in cooling water temperature is an explanatory diagram of a temperature change in the furnace bottom side wall bricks.

As shown in FIG. 1, a blast furnace 10 to which a method for preventing wear of a blast furnace brick according to an embodiment of the present invention is applied. An iron skin 11, a furnace bottom brick 12 and a furnace bottom wall lined inside the iron skin 11. A brick 13, a bottom plate 14 that holds the furnace bottom brick 12, and tuyere 15 are provided. This will be described in detail below.

The furnace bottom brick 12 is stacked in a plurality of stages on the bottom board 14, and the furnace bottom side wall brick 13 is stacked in a plurality of stages in contact with the inner wall of the iron skin 11 on the outside and above the furnace bottom brick 12. 12 and the furnace bottom side wall brick 13 are united.
Two thermometers T ₀ and T ₁ are embedded at different positions in the thickness direction in the furnace bottom brick 12 with an interval of, for example, 30 to 100 cm. A single thermometer T ₂ for measuring the temperature of the furnace bottom side wall brick 13 is also embedded in the furnace bottom side wall brick 13. Each thermometer T ₀ , T ₁ , T ₂ can use a thermocouple, and each measured value of the thermometers T ₀ , T ₁ , T ₂ can be controlled. Part (not shown).
The bottom plate 14 is provided with a cooling pipe (not shown) so that the amount of cooling water supplied to the cooling pipe can be adjusted by an adjustment valve. The adjustment of the adjusting valve is controlled by the control unit described above.
Moreover, the blast furnace 10 is provided with tuyere 15 and can inject oxygen, pulverized coal, etc. in the blast furnace 10, can increase / decrease the injection amount ratio, and can increase / decrease the combustion temperature in the front 16 of tuyere.

Next, a method for preventing blast furnace brick wear according to an embodiment of the present invention will be described with reference to the blast furnace 10 described above.
When the blast furnace 10 is normal, there is no abnormal wear on the bottom wall brick 13 and the operation can be kept stable. However, a solidified layer (also referred to as a viscous layer) having metal and slag is abnormally formed on the surface of the furnace bottom brick 12 due to improper cooling of the bottom plate 14, abnormal conditions in the furnace, and the like. Depending on the amount of the solidified layer to be formed, a flow (annular flow) of hot metal along the bottom wall brick 13 of the hot metal is generated at the bottom of the blast furnace 10, and the bottom wall brick 13 is worn out. Moreover, since the abnormally formed solidified layer suppresses the heat at the bottom of the blast furnace 10 from being transmitted to the furnace bottom brick 12, in this case, the temperature of the furnace bottom brick 12 decreases. Thereby, since the furnace bottom brick 12 contracts, the furnace bottom side wall brick 13 integrated with the furnace bottom brick 12 moves to the center of the blast furnace 10, and between the iron skin 11 and the furnace bottom side wall brick 13, For example, a gap of 0.2 to 1 mm is formed. For this reason, even if it cools from the outer side of the iron skin 11, the furnace bottom side wall brick 13 cannot be cooled, but the furnace bottom side wall brick 13 is worn out. Therefore, in order to set the amount of the solidified layer formed on the furnace bottom brick 12 to an appropriate amount and eliminate the annular flow of the hot metal resulting from the solidified layer, the following adjustment is performed.

From the measured values of the two thermometers T ₀ , T ₁ embedded in the bottom brick 12 of the blast furnace 10, the through-flow heat quantity Q of the bottom brick 12 is obtained, and this through-flow heat quantity Q is within a predetermined range, that is, 2500 to 3400. The blast furnace operating conditions and the amount of cooling water flowing through the bottom plate 14 are adjusted so as to control at K cal / m ² · hr.
This through-flow heat quantity Q indicates the amount of heat transferred from the hot metal to the bottom plate 14 via the furnace bottom brick 12. From the measured values of the two thermometers T ₀ and T ₁ embedded in the furnace bottom brick 12, It can be obtained using an equation.
Q = λ × (T ₁ −T ₀ ) / L
Here, λ ( K cal / m · hr · ° C.) is a heat transfer coefficient (thermal conductivity) of the furnace bottom brick 12, and L (m) is a thermometer T ₀ , T ₁ embedded in the furnace bottom brick 12. The distance between each is shown. Note that λ is determined by the type of brick used for the furnace bottom brick 12.

Here, when the through-flow heat quantity Q exceeds 3400 K cal / m ² · hr, the temperature in the furnace rises, so the furnace bottom side wall brick 13 in contact with the hot metal is abnormally worn. On the other hand, when the through-flow heat quantity Q is less than 2500 K cal / m ² · hr, a lot of solidified layers are formed on the surface of the furnace bottom brick 12, and the convection (hot metal flow) toward the furnace bottom side wall brick 13 becomes stronger. The side wall brick 13 is worn abnormally. Moreover, since many solidified layers are formed on the surface of the furnace bottom brick 12, heat transmitted to the bottom board 14 through the furnace bottom brick 12 is reduced, and the temperature of the furnace bottom brick 12 is lowered and contracts. Thereby, the furnace bottom side wall brick 13 integrated with the furnace bottom brick 12 moves toward the center of the blast furnace 10, and a gap is generated between the furnace bottom side wall brick 13 and the iron skin 11. And the iron skin 11 cannot be maintained in contact with each other. For this reason, the furnace bottom side wall brick 13 cannot be cooled via the iron skin 11, and the furnace bottom side wall brick 13 is abnormally worn.
Therefore, in order to maintain the temperature in the furnace at a temperature at which the operation is stably performed, to prevent shrinkage of the furnace bottom brick 12 and to suppress wear of the furnace bottom side wall brick 13, a predetermined range of the through-flow heat quantity Q is set to 2600 to 2600. It is preferably 3300 K cal / m ² · hr, more preferably 2700 to 3200 K cal / m ² · hr.

Further, a temperature difference between the measured values is obtained from the measured values of the two thermometers T ₀ and T ₁ embedded in the furnace bottom brick 12, and this temperature difference is calculated as the heat of the two thermometers T ₀ and T ₁ . It is also possible to control the temperature gradient ΔT within a predetermined range, that is, 1 to 3.5 ° C./cm, by setting ΔT as the temperature gradient divided by the distance in the flow-through direction (the height direction of the blast furnace 10).
Here, the upper limit value of 3.5 ° C./cm, which is the upper limit value of the predetermined range of the temperature gradient ΔT, substantially corresponds to the upper limit value of 3400 K cal / m ² · hr of the predetermined range of the through-flow heat quantity Q described above, 1 ° C./cm, which is the lower limit value of the predetermined range of the temperature gradient ΔT, substantially corresponds to the lower limit value 2500 K cal / m ² · hr of the predetermined range of the heat flow amount Q described above. The predetermined range of the temperature gradient ΔT can be managed in a narrower range according to the thermal conductivity of the furnace bottom brick 12.

In order to control the obtained numerical value within the above-mentioned predetermined range, the amount of coke with respect to the amount of ore in the blast furnace 10 is increased or decreased, and the combustion temperature at the tuyere front 16 inside the tuyere 15 is increased or decreased. Here, when the obtained numerical value approaches the upper limit value of the predetermined range, the temperature in the furnace is higher than usual, so the reduction in the amount of coke relative to the amount of ore from the current state, and the combustion temperature at the tuyere 16 Reduce from the current level. On the other hand, when the obtained numerical value approaches the lower limit value of the predetermined range, the temperature in the furnace is lower than usual, so the increase in the amount of coke relative to the amount of ore from the current state, or the combustion temperature at the front 16 of tuyere Increase more. Thus, the inside of the blast furnace 10 can be maintained at an appropriate temperature. Here, any method may be used to increase / decrease the combustion temperature before the tuyere 16 as long as the combustion temperature can be increased / decreased, and examples include an increase / decrease in the oxygen amount ratio of the gas blown through the tuyere 15 and the pulverized coal amount ratio. As mentioned.

In addition, when the calculated | required numerical value is less than the lower limit of a predetermined range, since the temperature in a furnace becomes lower than usual and the temperature of the furnace bottom brick 12 falls, when the furnace bottom brick 12 contracts, A gap is formed between the furnace bottom side wall brick 13 and the iron skin 11 which are integrated, and the furnace bottom side wall brick 13 cannot be cooled by the iron skin 11. For this reason, this gap is filled with one or more fillers having a higher thermal conductivity than air, such as mortar, carbon paste, heavy oil, and CO ₂ gas. It is also possible to lower the cooling water temperature of the iron skin 11 outside the furnace bottom side wall brick 13 integrated with the furnace bottom brick 12 from the current level (for example, the current 30 ° C. cooling water temperature is reduced to 5 ° C.). is there. In addition, the cooling water temperature can be lowered using cooling water before being supplied to the iron skin 11 by using an apparatus such as air cooling or a refrigerator.
Thereby, the amount of heat conducted between the iron skin 11 and the bottom wall brick 13 can be increased, the bottom wall brick 13 can be cooled, and the wear of the bottom wall brick 13 can be suppressed.

The result of having applied and tested the blast furnace brick wear prevention method according to the present invention will be described. In addition, as the conditions of the bottom part of the blast furnace 10, the thickness of the furnace bottom brick 12 was set to 2 m or more, the thermometer T ₀ was embedded about 500 mm from the bottom board 14, and the thermometer T ₁ was buried at a position above the thermometer T ₀ by 500 mm or more. . In addition, the management range of the through-flow heat quantity Q was 2500 to 3400 K cal / m ² · hr, and the management range of the temperature difference of the measured values was 100 to 130 ° C. (within the predetermined range of the temperature gradient ΔT).

First, the first embodiment will be described.
As shown in FIG. 2 (A), when the blast furnace 10 is operated, for example, a large amount of solidified layer starts to adhere to the surface of the bottom brick 12, so that the heat flow through Q and the temperature difference between the measured values are increased over time. There is a tendency to lower to a control lower limit (Q = 2500 K cal / m ² · hr, temperature difference = 100 ° C.). At this time, before falling below the control lower limit value, as shown in FIG. 2B, ore / coke, that is, (ratio of ore amount to coke amount) is changed from the current 4.72 to 4.53, for example, 0.8. By reducing by 1 to 0.3, the amount of coke relative to the amount of ore is increased and the heat input in the furnace is increased. As a result, the once-through heat quantity Q once below the lower limit value of the management range and the temperature difference between the measured values can be returned to the management range over time. In addition, after the temperature difference of the through-flow heat amount Q and the measured value returns to the control range, ore / coke is gradually increased to 4.72 from the original (stepwise), and the stable operation of the blast furnace 10 is continued.

In addition, as shown in FIG.2 (C), the temperature of the furnace bottom side wall brick 13 rose 25 degreeC from normal 100 degreeC to 125 degreeC, after falling below a control lower limit. This is because the temperature of the furnace bottom brick 12 is lowered, the furnace bottom brick 12 is contracted, and a gap is formed between the furnace bottom side wall brick 13 and the iron shell 11 , and the furnace bottom side wall brick 13 can be cooled. Indicates that it has disappeared. However, since the temperature difference between the flow-through heat quantity Q and the measured value of the furnace bottom brick 12 returns to the control range by performing the above-described treatment, the furnace bottom side wall brick 13 and the iron skin 11 can be brought into contact again. For this reason, the temperature of the furnace bottom side wall brick 13 is lowered again to the original 100 ° C., and the wear of the furnace bottom side wall brick 13 can be suppressed.

Next, a second embodiment will be described.
As shown in FIG. 3 (A), when the temperature of the blast furnace 10 is increased, the temperature difference between the amount of through-flow heat Q and the measured value becomes a management upper limit value (Q = 3400 K cal as time passes). / M ² · hr, temperature difference = 130 ° C.). At this time, before exceeding the control upper limit value, as shown in FIG. 3 (B), the amount of cooling water in the bottom plate 14 is made to follow the rising curve of the heat flow through Q and the temperature difference between the measured values, and the current 30 tons / hour. To 38 tons / hour. In this way, by cooling the bottom brick 12 by strengthening the cooling of the bottom plate 14, the once-through heat quantity Q exceeding the upper limit value of the management range and the temperature difference between the measurement values are within the management range as time passes. Can be returned to. In addition, after the temperature difference between the through-flow heat quantity Q and the measured value returns to the control range, the cooling water amount of the bottom plate 14 is made to follow the descending curve of the through-flow heat quantity Q and the measured temperature difference, and the original 30 ton / Stable operation of the blast furnace will be continued by gradually reducing it to about time.

Subsequently, a third embodiment will be described.
As shown in FIG. 4 (A), when the blast furnace 10 is operated, for example, the solidified layer starts to adhere to the surface of the bottom brick 12, so that the temperature difference between the through-flow heat quantity Q and the measured value with the passage of time is lower than the control lower limit. There is a tendency to decrease to a value (Q = 2500 K cal / m ² · hr, temperature difference = 100 ° C.). At this time, the temperature of the furnace bottom brick 12 decreases, the furnace bottom brick 12 contracts, and a gap is formed between the furnace bottom side wall brick 13 and the iron skin 11 . Therefore, even if cooling water is applied from the outside of the iron shell 11, the furnace bottom side wall brick 13 cannot be cooled, and the temperature of the furnace bottom side wall brick 13 rapidly increases as shown in FIG. 4B. . Here, a filler having a higher thermal conductivity than air, for example, one or more of mortar, carbon paste, heavy oil, and CO ₂ gas is filled in the gap (side wall press-fitting). Therefore, the heat conduction between the iron shell 11 and the furnace bottom side wall brick 13 is ensured, so that the heat of the furnace bottom side wall brick 13 is transmitted to the iron skin 11 and the temperature of the furnace bottom side wall brick 13 is the original temperature. Can be cooled until
In addition, when a filler is not filled between the iron shell 11 and the furnace bottom side wall brick 13, as shown in FIG.4 (C), the temperature of the furnace bottom side wall brick 13 raised to 120 degreeC or more is long time. It turns out that it does not fall. For this reason, the furnace bottom side wall brick 13 is worn out.

A fourth embodiment will be described.
As shown in FIG. 5 (A), during operation of the blast furnace 10, for example, the solidified layer starts to adhere to the surface of the bottom brick 12, so that the temperature difference between the through-flow heat quantity Q and the measured value with time elapses. There is a tendency to decrease to a value (Q = 2500 K cal / m ² · hr, temperature difference = 100 ° C.). At this time, the temperature of the furnace bottom brick 12 decreases, the furnace bottom brick 12 contracts, and a gap is formed between the furnace bottom side wall brick 13 and the iron skin 11 . Therefore, at this time, before falling below the control lower limit value, as shown in FIG. 5 (B), the iron skin 11 is cooled by reducing the cooling water temperature of the iron skin 11 from the current 30 ° C. to 5 ° C., The iron skin 11 can be contracted with respect to the furnace bottom side wall brick 13 to suppress the generation of the gap or to eliminate the generated gap.
As a result, the once-through heat quantity Q once below the lower limit value of the management range and the temperature difference between the measured values can be returned to the management range over time.

In addition, as shown in FIG.5 (C), the temperature of the furnace bottom side wall brick 13 rose 18 degreeC from normal 100 degreeC to 118 degreeC, after falling below a control lower limit. This is because the temperature of the furnace bottom brick 12 is lowered, the furnace bottom brick 12 is contracted, and a gap is formed between the furnace bottom side wall brick 13 and the iron shell 11 , and the furnace bottom side wall brick 13 can be cooled. Indicates that it has disappeared. However, since the temperature difference between the flow-through heat quantity Q and the measured value of the furnace bottom brick 12 returns to the management range by performing the above-described treatment, the furnace bottom brick 12 is appropriately cooled. For this reason, the temperature of the furnace bottom side wall brick 13 falls to about 78 ° C., and wear of the furnace bottom side wall brick 13 can be suppressed.

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, the present invention is also applied when the blast furnace brick wear prevention method of the present invention is configured by combining some or all of the above-described embodiments and modifications.
Moreover, in the said embodiment, although the case where two thermometers were embed | buried in the furnace bottom brick was demonstrated, it is also possible to embed | buy three or more thermometers. In addition, the embedded positions of the thermometers can be set to arbitrary positions as long as the embedded positions of at least two thermometers are different positions in the thickness direction in the furnace bottom brick.

It is explanatory drawing of the blast furnace to which the wear prevention method of the blast furnace brick which concerns on one embodiment of this invention is applied. (A)-(C) is explanatory drawing which shows the change of the temperature difference of the through-flow heat amount and the thermometer measurement value of the furnace bottom brick which concerns on 1st Example, respectively, explanatory drawing which shows the change of ore / coke, a furnace bottom It is explanatory drawing of the temperature change of a side wall brick. (A), (B) is explanatory drawing which shows the change of the temperature difference of the through-flow heat amount of the furnace bottom brick which concerns on a 2nd Example, and the measured value of a thermometer, respectively, and explanatory drawing of the change of bottom board cooling water amount. (A)-(C) is explanatory drawing which shows the change of the temperature difference of the through-flow heat amount of the furnace bottom brick which concerns on 3rd Example, and the measured value of a thermometer, respectively, The temperature of the furnace bottom side wall brick at the time of use of a filler It is explanatory drawing of a change, and explanatory drawing of the temperature change of the furnace bottom side wall brick at the time of non-use of a filler. (A)-(C) is explanatory drawing which shows the change of the temperature difference of the through-flow heat amount of the bottom brick and the measured value of a thermometer which concerns on a 4th Example, respectively, explanatory drawing which shows the change of cooling water temperature, a furnace bottom It is explanatory drawing of the temperature change of a side wall brick.

Explanation of symbols

10: Blast furnace, 11: Iron skin, 12: Brick at the bottom of the furnace, 13: Brick at the bottom of the furnace bottom, 14: Bottom board, 15: Tuyere, 16: In front of the tuyere

Claims (6)

At least two thermometers are buried at different positions in the thickness direction in the bottom brick of the blast furnace, and the through heat of the bottom brick is obtained from the measured value of the thermometer, and the through heat is controlled within a predetermined range. In this case, the predetermined range of the heat flow through is 2500 to 3400 Mcal / m ² · hr, and a method for preventing blast furnace brick wear. The method for preventing wear of a blast furnace brick according to claim 1, wherein the amount of coke relative to the amount of ore in the blast furnace is increased or decreased in order to control the obtained numerical value within the predetermined range. . The blast furnace brick according to any one of claims 1 and 2, wherein the combustion temperature before the tuyere is increased or decreased in order to control the obtained numerical value within the predetermined range. How to prevent wear. The method for preventing wear of a blast furnace brick according to any one of claims 1 to 3, wherein when the obtained numerical value falls below a lower limit value of the predetermined range, the furnace bottom brick is integrated with the furnace bottom brick when shrinking. A method for preventing wear of a blast furnace brick, characterized in that a gap generated between the bottom wall brick and the iron shell is filled with a filler having a higher thermal conductivity than air. The method for preventing wear of blast furnace brick according to claim 4, wherein the filler is any one or more of mortar, carbon paste, heavy oil, and CO ₂ gas. In the wear prevention method of the blast furnace brick of any one of Claims 1-5, when the calculated | required numerical value is less than the lower limit of the said predetermined range, the bottom wall brick outer side united with the said furnace bottom brick is integrated. A method for preventing wear of blast furnace bricks, characterized by lowering the cooling water temperature of the iron skin from the current level.

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