JPH0967607A - Method for monitoring furnace bottom of blast furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the wearing of furnace bottom refractories, and also, to drastically extend the service life of a blast furnace by developing a solidified layer, by three- dimensionally detecting the wearing in the circumferential direction of the furnace bottom refractories of the blast furnace and taking the measure for the wear in each circumferential direction. SOLUTION: Plural thermal flowmeters 3 and thermocouples 4 are arranged in the furnace bottom 2 and in the height direction of the blast furnace 1 to measure the heat flow quantity and the temp. of the furnace bottom brick 5. Further, the thermal flowmeters 3 and the thermocouples 4 are arranged in the brick and the back surface of the brick even in the furnace side wall 6 part to always measure the heat flow quantity and the temp. Since a joint eroding range 7 is formed on the upper part of a sound brick 5 in the furnace hearth of the blast furnace and the solidified layer 8 of molten material in the furnace as a protecting layer is formed on the joint eroding range 7 at the boundary part between the side wall 6 of the furnace bottom, a three-dimensional heat transfer analysis is executed to the heat flow quantity distribution and the temp. distribution in the bricks 4. Then, the calculated values of the heat flow quantity and the temp. at the brick heat flow quantity measuring point and the actually measured values are compared, and the joint eroding surface is adjusted by these differences, and the distributing condition of the solidified layer 8 on the surface is grasped to suitably execute the prevention of wearing of the furnace bottom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention three-dimensionally estimates the erosion shape of the furnace bottom refractory of the blast furnace and the shape of the solidified layer of the furnace melt formed on the furnace bottom refractory, and extends the life of the blast furnace. The present invention relates to a method for monitoring the bottom of a blast furnace capable of taking measures to prevent wear and tear.

[0002]

2. Description of the Related Art In recent low economic growth situations,
It is becoming an important issue to extend the life of the blast furnace and lower the unit cost of pig iron while maintaining stable operation, instead of the harsh operating conditions of the conventional blast furnace in pursuit of high productivity and the large size by rewinding.

Usually, the life of a blast furnace can be extended and repaired during a blast because there is a technique such as the replacement of staves from the tuyere to the upper part, but there is hot metal in the hot water pool at the bottom of the furnace. It was determined by the wear of the bottom refractory because it could not be easily repaired.

Therefore, for stable operation of the blast furnace and extension of its life, it is important to constantly grasp the erosion condition of the bottom refractory during the operation of the blast furnace and to take measures to prevent the wear of the erosion site promptly and appropriately. However, at the same time, by observing the distribution of the solidified layer of the molten material in the furnace that is repeatedly generated and disappeared on the erosion surface of the refractory due to the measures to prevent wear of the eroded part, the solidification layer thickness and It is also important to control the layer thickness distribution.

That is, it is desirable that the solidified layer which is repeatedly formed and disappears on the erosion surface of the refractory material is thickly formed over the entire erosion surface of the furnace bottom refractory material from the viewpoint of refractory material protection.
If the solidified layer grows above the tapping level, the bottom of the furnace is likely to be cooled, which hinders tapping work. In addition, when the solidified layer locally grows largely in the center of the furnace bottom, the flow path of the molten pig iron becomes small and the liquid flow resistance increases, and the amount of molten pig iron that can be discharged in one tapping work decreases. However, since the melt tends to remain in the hearth, the air permeability of the entire furnace is deteriorated and the unloading of the charged material is deteriorated.

Therefore, in order to achieve both stable tapping work and effective protection of the furnace bottom refractory, a technique capable of controlling the fluctuating of the furnace bottom solidification layer was established and the optimum solidification layer thickness and distribution were determined. And it is necessary to operate the blast furnace under optimum conditions. For this purpose, it is important to predict the erosion shape of the blast furnace refractory and the shape of the solidified layer of the in-furnace melt formed on the bottom refractory.

Conventionally, as a method of predicting the erosion shape of the bottom refractory and the solidified layer shape of the in-furnace melt formed on the bottom refractory based on the temperature of the bottom of the blast furnace, the method of predicting the inside of the bottom refractory and / Or based on the results of furnace bottom temperature measurement by multiple temperature sensors arranged on the outer surface of the furnace bottom refractory, the arrival of the highest temperature through the operation transition of the blast furnace is detected, and the boundary element method is used from the highest temperature. Predict the erosion shape of the furnace bottom refractory by heat transfer analysis as an axisymmetric body with the vertical axis of the furnace as the axis of symmetry, and then measure the furnace bottom temperature with multiple temperature sensors in the range where the furnace bottom temperature is lower than the maximum temperature. The heat transfer analysis is performed by using the boundary element method based on the continuously measured temperature and the predicted erosion shape of the furnace bottom refractory as an axisymmetric body with the vertical axis of the furnace bottom as the axis of symmetry. Solidified layer of in-furnace melt formed on the eroded and eroded bottom refractory If a new maximum temperature is detected through the operation transition of the blast furnace, the heat transfer is performed from the new maximum temperature using the boundary element method as an axisymmetric body with the vertical axis of the furnace bottom as the axis of symmetry. Predict the erosion shape of the bottom refractory by analysis, then continue to measure the bottom temperature with multiple temperature sensors in the range where the bottom temperature is lower than the new maximum temperature, and predict the temperature measured continuously Based on the eroded shape of the bottom refractory, the heat transfer analysis was performed using the boundary element method as an axisymmetric body with the vertical axis of the bottom being the axis of symmetry, and the furnace produced on the eroded bottom refractory was analyzed. A bottom monitoring method that constantly monitors the erosion shape of the furnace bottom refractory and the shape of the solidified layer of the furnace melt formed on the furnace bottom refractory by repeatedly predicting the shape of the solidified bed of the inner melt (Japanese Patent Publication 61). Japanese Patent Publication No. 61-37328). Based on the solidified layer shape of the furnace melt generated on the furnace bottom refractory predicted by the disclosed furnace bottom monitoring method, its thickness and distribution is controlled by the selection of blast furnace operating conditions including the furnace bottom cooling conditions, An operation method for constantly monitoring the predicted erosion growth of the furnace bottom refractory and continuously monitoring the erosion shape of the furnace bottom refractory and the solidified layer shape of the in-furnace melt formed on the furnace bottom refractory (Japanese Patent Publication No.
No. 37327/1991) is proposed.

The methods disclosed in Japanese Patent Publication No. 61-37328 and Japanese Patent Publication No. 61-37327 disclose a furnace bottom by heat transfer analysis using a finite element method as an axisymmetric body whose longitudinal axis is the axis of symmetry. It is intended to predict the erosion shape of a refractory and the shape of the solidified layer of the in-furnace melt formed on the eroded furnace bottom refractory. For this reason, the eroded shape of the furnace bottom refractory in the circumferential direction of the furnace and the solidified layer shape of the in-furnace melt generated on the eroded furnace bottom refractory were determined only by average values.

However, when there are many tap holes on the bottom of the blast furnace, the hot metal flows toward the tap holes, so that the flow of the hot metal is not axisymmetric. Therefore, as shown in FIG. 15A, the erosion 22 on the bottom of the blast furnace 21 is
The erosion 22 does not proceed symmetrically with respect to the axis 23, and as shown in FIG. Further, in a certain direction, the erosion of the hearth bottom refractory sometimes progresses locally, and this local erosion of the hearth bottom refractory becomes the life-determining rate of the actual furnace. Therefore,
Countermeasures against the erosion of the bottom refractory of the blast furnace must be planned based on the erosion line estimation result by the three-dimensional model.

As a method for estimating an erosion line using a three-dimensional model, based on the furnace bottom temperature distribution measured by temperature sensors arranged three-dimensionally in the furnace bottom refractory and / or on the outer surface of the furnace bottom refractory, A three-dimensional heat transfer analysis is performed using the finite element method, the boundary element method or the finite difference method, and the erosion shape of the hearth refractory is determined, and the area where erosion is progressing is compared with the deepest erosion shape in the past. It was updated and three-dimensional heat transfer analysis was performed using the finite element method, boundary element method, or finite difference method based on the above-mentioned temperature distribution of the bottom of the furnace, and the shape of the joint surface of the bottom of the refractory of the bottom was calculated and found in advance. The advanced joint surface area compared to the joint surface shape is updated, and the joint surface shape and the deepest erosion shape in the past are compared to solidify between the deepest erosion surface in the past and the joint surface inside the furnace. Repeatedly making a layer,
Estimate the erosion shape of the bottom refractory steadily or unsteadily and the solidified layer shape of the in-furnace melt generated on the eroded bottom bottom refractory, and localize the locally eroded part When the erosion prevention measure is totally eroded, an operation method for taking the overall erosion prevention measure (Japanese Patent Laid-Open No. 6-1364).
No. 20) has been proposed.

[0011]

[Patent Document 1] Japanese Unexamined Patent Publication No. 6-136
In the three-dimensional heat transfer analysis disclosed in Japanese Patent Publication No. 420, the boundary condition of the bottom plate and the side wall depends on the cooling condition, for example, the bottom plate is water-cooled at 20 ° C. and the overall heat transfer coefficient is 25 Kca.
1 / m ² / hr / ° C., water cooling of the side wall was set to 20 ° C., and the overall heat transfer coefficient was set to a constant value of 200 Kcal / m ² / hr / ° C. For this reason, there have been cases where the erosion situation cannot be accurately estimated only by the temperature measurement values of the temperature sensors provided inside the furnace bottom refractory and / or on the outer surface of the furnace bottom refractory. That is, when the heat flow rate is high, the heat load is large even if the temperature sensor is at a low temperature, resulting in erosion, and conversely, if the heat flow rate is low even if the refractory temperature is high, the refractory remains. There may be more or solidified layer growth.

The reason is that the life of the blast furnace has been about 5 years in the past, but recently it has been extended to more than 15 years. Therefore, in particular, the stamp material and the iron shell, which are packed between the iron shell and the refractory, or It is presumed that this is because the adhesion of the stamp material to the refractory changes and the transmission of the cooling effect of the steel skin to the refractory changes. As for the bottom of the furnace bottom, it may be diverted at the time of refurbishment, and it has been used for 30 years continuously. In such a case, it is conceivable that the heat transfer coefficient below the bottom plate changes with time due to deterioration of the water-cooled pipe below the bottom plate, water leakage, or the influence of deposits on the inner surface of the pipe.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, and even when the overall heat transfer coefficients of the bottom plate and the side wall are changed, the erosion shape and the in-furnace melting generated on the eroded furnace bottom refractory It is an object of the present invention to provide a method for monitoring the bottom of a blast furnace, which can accurately estimate the solidified layer shape of an object.

[0014]

[Means for Solving the Problems] The present inventors have conducted various test studies in order to achieve the above object. As a result, the finite element method (hereinafter referred to as FEM), the boundary element method (hereinafter referred to as BEM), or the finite difference method (hereinafter referred to as FDM) is used based on the heat flow distribution of the blast furnace bottom refractory or the heat flow distribution and temperature distribution. Heat transfer analysis using a three-dimensional model to determine the erosion shape, joint joint surface shape and solidification layer shape of the bottom refractory
By dimensionally obtaining, it was clarified that the erosion state in the circumferential direction of the furnace bottom refractory and the shape of the solidified layer of the molten material in the furnace generated on the corroded furnace bottom refractory can be accurately predicted, and the present invention Arrived

That is, the present invention provides a method for monitoring the bottom of a blast furnace, which monitors the erosion state of the bottom refractory of the blast furnace and the solidification shape of the in-furnace melt formed on the eroded refractory.
Based on the heat flow distribution of the bottom of the furnace bottom refractory and / or the outer surface of the bottom refractory, which is three-dimensionally arranged at a plurality of locations, the three-dimensional transmission is performed using FEM, BEM or FDM. Thermal analysis is performed to find the erosion shape of the bottom refractory, and the area where the erosion is progressing is updated by comparing with the deepest erosion shape in the past. Based on the bottom bottom heat flow distribution, FEM, BE
A three-dimensional heat transfer analysis is performed using M or FDM to obtain the joint joint surface shape of the furnace bottom refractory and update the joint joint surface area that has progressed in comparison with the joint joint surface shape previously obtained. Compared with the joint surface shape and the deepest erosion shape in the past, the solidification layer between the deepest erosion surface in the past and the joint surface inside the furnace was repeatedly used to steadily or unsteadily A method for monitoring the bottom of a blast furnace, characterized by estimating the erosion shape and the solidification shape of the molten material in the furnace generated on the eroded furnace bottom refractory.

Further, according to the present invention, the erosion state of the furnace bottom refractory and the solidified shape of the in-furnace melt produced on the corroded refractory are determined based on the heat flow rate or temperature of the bottom and side walls of the blast furnace. In the method of monitoring the bottom of the blast furnace to be monitored,
Based on the furnace bottom heat flow distribution and the furnace bottom temperature distribution measured by a heat flow meter and a temperature sensor arranged in a plurality of three-dimensionally inside the furnace bottom refractory and / or the outer surface of the furnace bottom refractory, a FEM, BEM or Perform three-dimensional heat transfer analysis using FDM, find the erosion shape of the bottom refractory, and update the area where erosion is progressing compared to the deepest erosion shape in the past,
FEM based on the furnace bottom heat flow distribution and the furnace bottom temperature distribution,
Perform three-dimensional heat transfer analysis using BEM or FDM,
Finding the joint surface shape of the hearth refractory and comparing the previously calculated joint surface shape with the updated joint surface area, and comparing the joint surface shape with the deepest erosion shape in the past. Repeatedly forming a solidified layer between the deepest erosion surface and the joint surface inside the furnace, steadily or unsteadily the erosion shape of the bottom refractory and the furnace generated on the eroded bottom refractory It is a method for monitoring the bottom of a blast furnace, characterized by estimating the solidification shape of the inner melt.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described below with reference to FIGS. 1 to 9 showing an example of an embodiment in which a heat flow meter and a thermocouple are used. Fig. 1 is a sectional view of the bottom of the blast furnace showing the installation positions of a heat flow meter as a heat flow sensor and a thermocouple as a temperature sensor, and Fig. 2 shows a heat flow meter and a thermocouple in the height direction of the blast furnace. The installation positions are shown in Fig. 1 (a), which is the installation positions of the heat flow meters and thermocouples of levels A to D in Fig. 1, and (b) is the installation positions of the thermocouples in levels E and F of Fig. 1. , (C) is an installation position diagram of the level G heat flow meter of FIG. 1, FIG. 3 is a vertical cross-sectional view showing the state of the bottom of the blast furnace, FIG. 4 is an explanatory view of a method for setting the floor of the furnace bottom, and FIG. Is an explanatory diagram of the brick erosion line estimation method when using the temperature measured by the temperature sensor, and FIG. 6 is an explanatory diagram of the brick erosion line estimation method when the heat flow measurement value is used when the heat flow sensor is used. FIG. 7 is an explanatory diagram of a method for determining the solidified layer in the bottom of the furnace, and FIG. 8 is a thermal conductivity distribution diagram of the bottom of the blast furnace. FIG. 9 shows the distribution of the overall heat transfer coefficient in the furnace bottom height direction (level B in FIG. 1) obtained from the heat flow rate.

As shown in FIGS. 1 and 2, the bottom plate 2 of the furnace bottom of the blast furnace 1 usually has 4 to 6 or more orientations, and 2 in the height direction.
The heat flow meter 3 and the thermocouple 4 are installed in steps or more, and the heat flow and the temperature of the brick 5 are measured. At the side wall 6 part, the heat flow meter 3 and the thermocouple 4 are in the brick in four directions or more and on the back surface of the brick. Is installed to measure heat flow and temperature.
The larger the number of measurement points, the more accurately three-dimensionally the bottom bottom refractory wear shape, joint surface shape, and solidified layer shape can be obtained. It is also possible to install only the heat flow meter 3 and measure only the heat flow rate.

As shown in FIG. 3, in the hearth of the blast furnace 1, the joint area 7 is formed on the upper part of the sound brick 5, and the solidified layer 8 is formed on the joint area 7 at the boundary with the side wall 6 of the furnace bottom. To be done.
In addition, 9 shows a hot metal + coke lump. First, assuming a three-dimensional shape of the joint surface of the hearth, the joint isothermal surface is set at 1150 ° C., which is the pig iron solidification temperature, and the heat flow rate is measured by the heat flow meter 3 as shown in FIGS. 1 and 2. Therefore, the heat flow rate is given as a boundary condition. Alternatively, the overall heat transfer coefficient is assumed to be equal to the measured heat flow rate.

Under the above conditions, the heat flow distribution and temperature distribution in the brick are three-dimensionally analyzed by heat transfer using FEM, BEM or FDM, and the calculated heat flow and the measured heat flow at the brick heat flow measurement point are measured. If the measured heat flow rate is lower than the calculated heat flow rate, the joint surface is raised. Conversely, if the measured heat flow rate is higher than the calculated heat flow rate, the joint surface is further advanced. In addition, the calculated temperature at the brick temperature measuring point is compared with the measured temperature.If the measured temperature is lower than the calculated temperature, the joint surface is raised, and conversely, if the measured temperature is higher than the calculated temperature, the joint temperature is higher. Further advance the side.

As shown in FIG. 4, the above method for raising the joint surface and for advancing the joint surface is set in the calculation area up to a height h substantially equal to the radius of the bottom of the furnace, and the origin O is set at the height h of the core 10. Then, a straight line is drawn radially from the origin O toward each measurement point 11 on the brick 5 and the side wall 6 of the furnace bottom, and the intersection point between this straight line and the initially assumed joint surface 12 is P. If the calculated value at each measurement point 11 of the brick is lower than the actual measurement value, the joint point surface 12 corresponding to the temperature difference (ΔT) or the heat flow difference (Δq) is Δx or Δxa with respect to the origin O. It is moved and this point is designated as P '. However, as shown in FIG. 5, Δx is given by Δx = (refractory thickness / 1150 ° C.) · ΔT in the case of temperature measurement. Further, as shown in FIG. 6, in the case of heat flow measurement,
Δxa = − (refractory thickness / calculated heat flow rate) · Δq In this way, the joint-joint surface 12 is moved according to the difference between the measured value and the calculated value, and the joint-joint surface shape is determined.

With the shape of the joint surface 12 thus updated as an initial value, the boundary condition between the bottom plate 2 and the side wall 6 is the cooling condition, the water cooling of the bottom plate 2 is 20 ° C., and the overall heat transfer coefficient is 25 Kcal / m ² / hr / ℃, water cooling of side wall 5 to 20 ℃
The overall heat transfer coefficient is given as 200 Kcal / m ² / hr / ° C. When the heat flow rate is measured like the measurement points indicated by black circles in FIGS. 1 and 2, the heat flow rate is given as a boundary condition. Alternatively, the overall heat transfer coefficient is assumed to be equal to the measured heat flow rate. Under the boundary conditions, the heat flow distribution and temperature distribution in the brick are three-dimensionally FE
It is determined by heat transfer analysis using M, BEM or FDM.
Then, by repeatedly raising the joint surface 12 or advancing the joint surface 12 by the above-described method, the difference between the calculated value and the actually measured value is reduced, and the difference is equal to or less than a certain value which is all the measurement points 11. It is assumed that it has converged at the time.

Since the measurement positions inside the brick are distributed discretely, the points on the joint surface estimated by the measurement positions are also discrete. Therefore, a three-dimensional spline function is used to complement the surface from points. If the joint surface 12 after convergence is located at a position where erosion has progressed from the previously determined joint surface 12, it is considered that the joint has advanced, and the joint surface 12 is displayed on the CRT screen,
Notify the blast furnace operator.

If the joint surface 12 is determined by the above operation, the solidified layer shape can be determined. That is, as shown in FIG. 7, a solidification layer 8 is formed between the deepest brick in the past and the joint surface 12 which is determined to be raised from the erosion surface 13a. Note that reference numeral 12a denotes the deepest jointed surface in the past.

The brick erosion surface 13 is defined as an isothermal surface (about 1350 ° C.) generally higher than the joint joint surface 12. In the estimation of the brick erosion surface 13, first, the brick erosion surface 13 is assumed and the temperature is given on this surface (1350 ° C.) to determine the heat flow distribution or temperature distribution in the brick 3 as in the estimation of the joint surface 12. Heat transfer analysis is performed dimensionally using FEM, BEM or FDM. The boundary conditions of the bottom plate 2 and the side wall 5 in this case are the same as the boundary conditions used for the estimation of the joint surface 12. Then, by comparing the calculated value at the brick measurement point of the brick erosion surface 13 with the actual measurement value, and repeating the operation of raising the brick erosion surface or advancing the brick erosion surface by the above method, the difference between the calculated value and the actual measurement value is obtained. Is set to be small, and it is assumed that the difference converges when all the measurement points become equal to or less than a certain value. The method for converging the brick erosion surface 13 is the same as the estimation algorithm for the joint surface 12.

The estimated converged brick erosion surface 1
3 compares the deepest brick erosion surface 13a in the past, and if the deepest brick erosion surface 13a is in a position where erosion has progressed from the erosion surface 13a, it is considered that the brick erosion surface 13 has progressed, and the brick erosion surface 13 is displayed on the CRT screen. It will be displayed on the screen and will be notified to the blast furnace operator. Conversely, if the converged brick erosion surface 13 is located at a position higher than the deepest brick erosion surface 13a in the past, the deepest brick erosion surface 13a in the past is displayed on the CRT screen and the blast furnace operator is notified immediately.

A three-dimensional FEM, BEM or FD
In the heat flow rate of M or the heat flow rate and temperature calculation, the thermal conductivity of the brick measured at the time of construction is used in the region outside the furnace and lower than the joint temperature of the joint surface 12a, which is the deepest point in the past. A region lower than the brick erosion temperature in a region inside the furnace inside the furnace and outside the deepest brick erosion surface 13a in the past is considered to be an altered brick layer (a layer in which molten iron penetrated into the brick during construction). As the thermal conductivity of the altered brick layer, a value between the thermal conductivity of the brick at the time of construction and the thermal conductivity of pig iron is used. The degree of penetration of hot metal differs depending on the material of the brick, but with chamotte brick it is 20 Kcal / m · hr ·
℃. The inside of the furnace, which is the deepest brick erosion surface in the past, is considered to be a pig iron solidified layer, and the thermal conductivity is 12 Kcal from actual furnace results.
/ M · hr · ° C.

FIG. 8 shows an example of a distribution diagram of the thermal conductivity λ according to the above. The unit of thermal conductivity λ in FIG. 8 is Kca.
1 / m · hr · ° C. FIG. 9 shows an example of the circumferential distribution of the overall heat transfer coefficient of the bottom plate 2 or the side wall 6 obtained as described above at level B in FIG. The unit of the overall heat transfer coefficient in FIG. 9 is Kcal / m ² / hr / ° C.
Further, the distribution of the overall heat transfer coefficient of the bottom plate 2 or the side wall 6, the erosion surface of the furnace bottom, the adhered state of the solidified layer, the alteration of brick, the joint condition and the temperature distribution are three-dimensionally displayed on a CRT screen as a graph, and Report to the operator.

If it is found from the result of the three-dimensional graph display on the CRT screen that the bottom of the furnace is locally eroded, the blast furnace operator can strengthen the cooling of the local erosion direction and move to the local erosion direction. Mortar injection (including mud injection to taphole), reduction of air flow to local erosion direction tuyere, injection of Ti powder ore to local erosion direction tuyere, Ti ore to local erosion direction In case of the charging of, the strengthening of the cooling of the bottom plate, and the wear around the taphole, measures such as increasing the taphole depth will be implemented.

As described above, according to the present invention, the heat flow rate sensor or the heat flow rate sensor and the temperature sensor which are three-dimensionally arranged at a plurality of locations inside the furnace bottom refractory and / or on the outer surface of the furnace bottom refractory. FEM, BEM or F based on heat flow distribution or bottom heat flow distribution and bottom temperature
Three-dimensional heat transfer analysis using DM is performed to obtain three-dimensionally the erosion shape, joint shape, and solidified layer shape of the molten material in the furnace generated on the eroded furnace bottom refractory. From this, it is possible to detect uneven wear in the circumferential direction of the furnace bottom refractory.

For the locally worn portion, local erosion prevention measures such as stopping blowing air from the tuyere directly above or blowing Ti ore powder from the tuyere are taken. To prevent wear. In addition, in the direction where the jointing is progressing, the jointing progress is prevented by filling the gap between the stamp material between the steel bar and the brick and taking measures to prevent the joint penetration such as strengthening the steel water cooling. The blast furnace life can be greatly extended.

[0032]

EXAMPLE As shown in FIG.
o. No. 1 tap hole 14 and No. 1 It was found that refractory erosion near the taphole 15 was severe. No. 1 tap hole 14 and No. 1 2 Press in the button 16 from the tap hole 15,
Secured the tap depth. As a result, as shown in FIG. No. 1 tap hole 14 and No. 1 2 It was confirmed that the pig iron solidified layer 8 was formed in the vicinity of the taphole 15.

Further, as shown in FIG.
It was found that there was a portion 17 where the side wall refractory wear was severe in the ° direction, and the overall heat transfer coefficient there was reduced to 54 Kcal / m ² / hr / ° C. Therefore, 30 on the bottom wall of the furnace
When stamping was carried out on the inner surface of the iron skin in the 0 ° direction,
As shown in FIG. 13, it was confirmed that the thermal conductivity of the side wall of the furnace bottom in the direction of 300 ° was increased and the solidified layer 8 was formed in the furnace. Further, when Ti powder ore was blown from the tuyere into the portion 17 of the side wall of the furnace bottom where the refractory wear was severe at 300 °, as shown in FIG. 14, the TiO ₂ solidified layer 18 was formed on the surface of the solidified layer 8. It was confirmed.

[0034]

As described above, according to the method of the present invention, wear in the circumferential direction of the blast furnace bottom refractory is accurately detected three-dimensionally, and various measures are taken for each circumferential direction. By preventing wear and generating a solidified layer, the maximum life of the conventional blast furnace, which is up to 13 years, can be greatly extended to 20 years, and the facility investment for blast furnace rewinding can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a furnace bottom cross-sectional view showing a heat flow meter or a position where a heat flow meter and a thermocouple are installed on the bottom of a blast furnace.

FIG. 2 is a view showing the installation positions of a heat flow meter or a heat flow meter and a thermocouple in the height direction of the blast furnace bottom, and FIG. 2 (a) is a diagram showing the heat flow meter or the heat flow meter of levels A to D in FIG. Installation position diagram of thermocouple, (b) diagram is installation position diagram of thermocouple of level E and F in FIG. 1, (c) diagram is heat flow meter of level G of FIG. 1 or heat flow meter and installation of thermocouple FIG.

FIG. 3 is a vertical cross-sectional view showing the state of the bottom of the blast furnace.

FIG. 4 is an explanatory diagram of a method of setting the floor surface of the hearth bottom.

FIG. 5 is an explanatory diagram of a method of estimating a brick erosion line from a temperature measurement result.

FIG. 6 is an explanatory diagram of a method of estimating a brick erosion line from a heat flow rate measurement result.

FIG. 7 is an explanatory diagram of a method for determining a furnace bottom solidified layer.

FIG. 8 is a thermal conductivity distribution diagram of the bottom of the blast furnace.

FIG. 9 is a circumferential distribution diagram (level B in FIG. 1) of the overall heat transfer coefficient in side wall cooling obtained from the result of heat flow meter measurement on the bottom wall of the blast furnace bottom.

FIG. 10 is an explanatory diagram of wear of a refractory near the taphole in the example.

FIG. 11 is also an explanatory view of forming a solidified layer after press-fitting a slag from the tap hole.

FIG. 12 is an explanatory view of wear of a side wall refractory of the furnace bottom in the direction of 300 °.

FIG. 13 is an explanatory view of the formation of a solidified layer after the stamping is performed on the inner surface of the iron shell of the furnace bottom in the 300 ° direction.

FIG. 14 is an explanatory diagram of solidified layer formation after injecting Ti powder ore from tuyere into the wear part of the side wall refractory in the 300 ° azimuth direction of the furnace bottom.

15A and 15B show the erosion state of the bottom of the blast furnace, where FIG. 15A is a vertical sectional view, and FIG. 15B is a sectional view taken along the line AA of FIG. 15A.

[Explanation of symbols]

1, 21 Blast furnace 2 Bottom plate 3 Heat flow meter 4 Thermocouple 5 Brick 6 Side wall 7 Joint region 8 Solidification layer 9 Hot metal + coke lump 10 Core 11 Temperature measuring point 12 Joint surface 13 Brick erosion surface 14 No. 1 tap hole 15 No. 2 tap hole 16 button 17 side wall where refractory wear is severe 18 TiO ₂ solidified layer 22 erosion 23 shaft 24 tap hole

Claims (2)

[Claims] 1. A method for monitoring the bottom of a blast furnace, wherein the erosion state of the bottom refractory of the blast furnace and the solidified shape of the in-furnace melt formed on the eroded refractory are monitored in the bottom refractory of the blast furnace and / or Based on the heat flow distribution of the hearth bottom measured by the heat flowmeters arranged three-dimensionally on the outer surface of the hearth refractory,
A three-dimensional heat transfer analysis is performed using the finite element method, the boundary element method or the finite difference method, the erosion shape of the hearth refractory is obtained, and the area where erosion is progressing is compared with the deepest erosion shape in the past. Update and perform three-dimensional heat transfer analysis using the finite element method, boundary element method, or finite difference method based on the heat flow distribution of the bottom of the furnace, and obtain the shape of the joint surface of the bottom of the refractory for the refractory The joint surface area that has advanced in comparison with the joint surface shape is updated, and the joint surface shape and the deepest erosion shape in the past are compared, and the space between the deepest erosion surface and the joint surface inside the furnace is compared. A blast furnace characterized by steadily or unsteadily estimating the erosion shape of the bottom refractory and the solidification shape of the in-furnace melt generated on the eroded bottom refractory by repeating the solidification layer Bottom monitoring method. 2. A method for monitoring the bottom of a blast furnace, wherein the erosion state of the bottom refractory of the blast furnace and the solidified shape of the in-furnace melt formed on the eroded refractory are monitored in the bottom refractory of the blast furnace and / or A finite element method, a boundary element method, or a finite difference method is used based on the heat flow distribution and the bottom temperature distribution of the bottom measured by a heat flow meter and a temperature sensor that are arranged three-dimensionally on the outer surface of the bottom refractory. The three-dimensional heat transfer analysis is performed using the erosion shape of the furnace bottom refractory, and the area where erosion is progressing is updated in comparison with the deepest erosion shape in the past. Three-dimensional heat transfer analysis is performed using the finite element method, boundary element method or finite difference method based on the temperature distribution, and the joint surface shape of the furnace bottom refractory is obtained and compared with the previously obtained joint surface shape. The joint surface area that has advanced The erosion shape of the bottom refractory is steadily or unsteadily compared with the depth of the deepest erosion surface and the solidification layer between the deepest erosion surface of the past and the joint surface inside the furnace. A method for monitoring the bottom of a blast furnace, comprising estimating the shape and the solidification shape of the molten material in the furnace generated on the eroded bottom refractory.