JP3740108B2 - Blast furnace hearth structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a blast furnace hearth structure, and more particularly, to a blast furnace hearth structure characterized by selection of a refractory used for blast furnace renovation.
[0002]
[Prior art]
As is well known, the hearth part of a blast furnace is always exposed to high temperatures, and thus is constructed with a refractory inside the iron skin.
Conventionally, when constructing or refurbishing a blast furnace, a refractory having the same hot metal corrosion resistance is uniformly used in the circumferential direction for the entire hearth.
By the way, there are various types of refractories for constructing a blast furnace, which have different hot metal corrosion resistance and thermal shock resistance. However, when constructing a blast furnace, particularly for a hot metal floor part exposed to high temperatures. It is preferable to use a refractory having excellent corrosion resistance and thermal shock resistance.
[0003]
[Problems to be solved by the invention]
However, since the price of a refractory excellent in hot metal corrosion resistance and thermal shock resistance increases, there is a problem that if the entire hearth is constructed of such a refractory, the cost increases. For this reason, in the conventional blast furnace hearth structure, in order to suppress the increase in cost, durability must be sacrificed. On the other hand, pursuing durability increases cost and it is difficult to balance the two. Met.
Therefore, in order to achieve both durability and cost reduction, a method of simulating the wear state of the refractory and defining the location where the refractory excellent in hot metal corrosion resistance and thermal shock resistance is arranged based on the result is provided. Conceivable. However, the simulation result and the actual wear state do not always coincide with each other, and in fact, there are many cases where the places where the wear is severe differ for each blast furnace.
This invention is proposed in view of the situation mentioned above, and it aims at providing the hearth structure of the blast furnace excellent in durability, suppressing the raise in cost.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-222615
[Means for Solving the Problems]
The hearth structure of a blast furnace according to the present invention has the following features in order to achieve the above-described object.
That is, the hearth structure of the blast furnace according to the present invention is based on the temperature distribution history measured using a thermometer embedded in the refractory when refurbishing without greatly changing the internal volume and profile of the blast furnace. When the wear of the floor side wall is estimated, and when it is clear that the hearth side wall is worn due to a special factor other than the hot metal flow inside the furnace in the furnace cost before the repair, the contribution is estimated, correcting the wear performance of the furnace floor side wall portion, in accordance with the wear performance of the hearth side wall, as refractory hearth sidewall portion constituting the furnace allowance after renovation, the wear in the furnace allowance before refurbishment greater This is characterized in that a material having a higher thermal conductivity is used for the part.
[0006]
Since the hearth structure of the blast furnace according to the present invention has the above-described configuration, it is possible to improve the durability in the portion of the hearth side wall where the wear of the refractory is large. Moreover, since a low-cost refractory can be used with respect to the site | part to which the wear of a refractory is not so large, the raise of cost can be suppressed.
Moreover, based on the temperature distribution history measured using the thermometer embedded in the refractory, the wear record of the hearth side wall can be easily estimated.
Furthermore, more accurate wear record can be obtained by correcting the wear record of the hearth side wall part in consideration of the actual investigation result or special factors in the hearth side wall part. For this reason, it is possible to further increase the durability and to reduce the cost by carrying out appropriate repairs.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of a hearth structure of a blast furnace according to the present invention will be described based on specific examples shown in the drawings.
<Estimation of actual wear>
In the hearth structure of the blast furnace according to the embodiment of the present invention, when refurbishing without greatly changing the internal volume and profile of the blast furnace, the cost of the furnace after refurbishment is configured according to the wear record of the hearth side wall. Select the refractory material for the hearth side wall.
The actual wear of the side wall of the hearth can be estimated based on the temperature distribution history measured using a thermometer embedded in the refractory. Although not shown in detail, a plurality of thermometers are embedded at appropriate locations on the hearth side wall.
[0008]
FIG. 5 is a diagram in which a wear profile at the time of blowing is estimated from a temperature distribution history measured using a thermometer embedded in a refractory. (A) shows a remarkable maximum wear portion in the height direction, and (b) shows a wear distribution in the circumferential direction with a height of 9 steps where the wear was most severe in the height direction.
Here, the estimation of the amount of refractory wear in the side wall of the hearth was performed as follows. The temperature distribution in the refractory can be calculated from the indicated value of a thermometer embedded in the refractory on the side wall of the hearth using the thermal conductivity of the refractory. Considering that the point at which the indicated value of the temperature type reached the highest temperature in each region is the time when wear finally progressed, the temperature distribution at that point is the temperature position of 1150 ° C, which is the freezing point of the hot metal, and the refractory remains. Estimated thickness.
As shown in FIG. 5, in the hearth side wall portion, the vicinity of the 8th to 9th steps 1 to 2 m below the taphole is most worn in the height direction, and Nos. 1, 2 and 3 in the circumferential direction. The vicinity of the spout is greatly worn compared to other parts. In particular, the wear near No. 3 dock is the largest. The wear within a range of 20 degrees as viewed from the spout is large. There is not much wear around the No. 4 dock.
In the hearth structure of the blast furnace according to the present embodiment, as the refractory material of the hearth side wall part constituting the furnace cost after the repair based on the estimation result of the wear results, the part where the wear was large in the furnace cost before the repair. Use materials with high thermal conductivity.
[0009]
<Example 1>
1 and 2 are schematic views showing a hearth structure of a blast furnace according to Embodiment 1 of the present invention, FIG. 1 is a schematic view showing the blast furnace as a cross section, and FIG. 2 is a schematic view of the blast furnace viewed from the side. It is.
In the hearth structure of the blast furnace according to the first embodiment, as shown in FIGS. In addition, the thermal conductivity is high and the hot metal corrosion resistance and the thermal shock resistance are excellent compared to the refractory 30A used for other parts with respect to the range of 20 degrees on each of the left and right sides with respect to the spout 20. Use refractory 30B.
Specifically, the refractory 30A having a thermal conductivity of 20 W / mK or 15 W / mK or more is used for most of the hearth side wall 10, and a specific range centering on the tap outlet 20 is A refractory 30B having a thermal conductivity of 25 W / mK or more is used.
[0010]
<Example 2>
FIGS. 3 and 4 are schematic views showing the hearth structure of the blast furnace according to the second embodiment of the present invention, FIG. 3 is a schematic view showing the blast furnace as a cross section, and FIG. 4 is a schematic view of the blast furnace viewed from the side. It is.
In the hearth structure of the blast furnace according to Example 2, the range in which the wear of the refractory is severely divided into two, and the range in which the wear is estimated to be even more severe, the thermal conductivity is higher and the hot metal corrosion resistance and the thermal shock resistance. Use an excellent refractory.
That is, in the hearth structure of the blast furnace according to the second embodiment, as shown in FIGS. 3 and 4, when constructing the hearth side wall portion 10, it is located below the taphole 20 and the taphole. A refractory 30B having a high thermal conductivity and excellent hot metal corrosion resistance and thermal shock resistance is used as compared with the refractory 30A used for other parts within a range of 30 degrees on each of the left and right sides with 20 as the center.
Furthermore, the heat conductivity is higher and the hot metal corrosion resistance and the thermal shock are within 1 to 3 m from the spout 20 to the lower side and within the range of 15 degrees to the left and right of the spout 20. Use refractory 30C with excellent properties.
Specifically, the refractory 30A having a thermal conductivity of 15 W / mK or more is used for most of the hearth side wall 10, and in a specific range centering on the taphole 20, A refractory 30B having a thermal conductivity of 20 W / mK is used, and a refractory 30C having a thermal conductivity of 25 W / mK or more is used in the central portion.
[0011]
<Other embodiments>
In the above-described Examples 1 and 2, the wear history of the refractory is estimated based on the temperature distribution history measured using the thermometer embedded in the refractory. At this time, if the actual wear record is found by the dismantling investigation before refurbishment, the estimated value can be corrected because this is more accurate. However, if it is clear that the hearth side wall 10 has been worn out due to special factors such as intrusion of water into the furnace due to the tuyere breakage other than the hot metal flow inside the furnace before the repair, the contribution is It is preferable to estimate and correct the wear record, that is, to subtract the estimated wear due to the special factor. By performing such correction, it is possible to more reliably estimate the wear record and to perform appropriate repairs.
In addition, the specific numerical value shown in Examples 1 and 2 is an example in the hearth structure of the blast furnace according to the present invention, and is appropriately selected according to various factors such as the hearth diameter of the blast furnace, the internal volume, the operation results, and the like. It is possible to carry out by selecting an appropriate numerical value.
[0012]
【The invention's effect】
Since the hearth structure of the blast furnace according to the present invention has the above-described configuration, the following effects can be achieved.
That is, according to the hearth structure of the blast furnace according to the present invention, since the repair is performed according to the wear record of the refractory, the durability in the portion where the wear of the refractory is large is increased, and the durability of the entire blast furnace is increased. be able to. In addition, since a low-cost refractory can be used for a portion where the wear of the refractory is not so great, the cost of the entire blast furnace can be reduced.
Moreover, the wear record can be easily estimated by estimating the wear record of the hearth side wall based on the temperature distribution history measured using the thermometer embedded in the refractory.
In addition, by taking into account actual survey results or special factors in the hearth side wall, by correcting the wear level of the hearth side wall part, it is possible to perform accurate repairs based on the accurate level of wear and durability. In addition, the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a schematic view (cross section) showing a hearth structure of a blast furnace according to Embodiment 1 of the present invention.
FIG. 2 is a schematic diagram (seen from the side) showing the hearth structure of a blast furnace according to Embodiment 1 of the present invention.
FIG. 3 is a schematic view (cross section) showing a hearth structure of a blast furnace according to Embodiment 2 of the present invention.
FIG. 4 is a schematic view showing a hearth structure of a blast furnace according to Embodiment 2 of the present invention (as viewed from the side).
FIG. 5 is a schematic diagram showing a refractory wear profile based on a temperature distribution history measured using a thermometer embedded in the refractory.
[Explanation of symbols]
10 hearth side wall 20 tap outlet 30A, B, C refractory

Claims (2)

When refurbishing without greatly changing the internal volume and profile of the blast furnace, the wear history of the hearth side wall is estimated based on the temperature distribution history measured using a thermometer embedded in the refractory, and before refurbishment. correcting the wear performance of the furnace floor side wall portion on the basis of the findings by the demolition of, in response to the wear performance of the hearth side wall, as refractory hearth sidewall portion constituting the furnace allowance after renovation, refurbishment A blast furnace hearth structure in which a material having higher thermal conductivity is used in a portion where wear was greater in the previous furnace cost. When refurbishing without greatly changing the internal volume and profile of the blast furnace, the wear history of the hearth side wall is estimated based on the temperature distribution history measured using a thermometer embedded in the refractory, and before refurbishment. When it is clear that the hearth side wall is worn due to a special factor other than the hot metal flow inside the furnace at the furnace cost, the contribution is estimated and the wear record of the hearth side wall is corrected, Depending on the actual wear of the hearth side wall, use a material with higher thermal conductivity as the refractory of the hearth side wall constituting the furnace cost after the refurbishment in the part where the wear was greater in the furnace cost before refurbishment. Blast furnace hearth structure characterized by

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