JPH05271729A - Method for repairing furnace wall of blast furnace and panel having thermal stress releasing function - Google Patents

Abstract

PURPOSE:To suitably restrain the heat load on a furnace body and to improve the durability of the inner surface of a furnace wall by using a non-water cooled inclining function type panel having the suitable thermal stress releasing function and also high degree mechanical characteristic in a repairing of the furnace wall of a blast furnace. CONSTITUTION:To a remained brick 4 in the damaging part of the furnace wall of a blast furnace and a worn stave cooler 5, the panel 7 is fixed with fixing bolts 8. Into a gap between the panel 7 and the surface of the inner wall, a high adhesive monolithic refractory 10 (phenol resin, etc.) is pressed and packed from a press-in nozzle 9 and cured. The panel 7 is substantially constituted of an aluminum series or non-oxide series ceramic material 7-2 on the surface A at the inner side of furnace and metallic material 7-1 on the surface B at the outer side of furnace. In both the surfaces, from the inner side of furnace to the outer side of furnace, the density of the ceramic material 7-2 is gradually made to low, and reversely, the density of the metallic material 7-1 is made to higher and higher, and the intermediate part C is made to an inclining function type structure composed of complex phase of the ceramic material 7-2 and the metallic material 7-1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a composite material of alumina or non-oxide ceramic material as a component and metallic material such as cast iron, and is composed of a functionally graded material having a thermal stress relaxation function. The present invention relates to a method of repairing a furnace wall of a blast furnace which is strong and capable of suppressing the heat load of the furnace body using a panel, and a panel made of a functionally graded material having a thermal stress relaxation function used in the method.

[0002]

2. Description of the Related Art Blast furnace lining refractories are gradually worn away due to cracks and peeling due to wear due to dropping of charging materials, heat load fluctuations in the furnace, corrosive gas attack, etc. To go. For this reason, the inner wall profile of the furnace wall becomes significantly non-uniform, disturbs the filling state of the charge, destabilizes the gas flow, increases heat outflow through the furnace wall, and causes hot spots on the iron shell. Cause cracks,
This is a major factor in shortening the furnace life. Particularly in a stave blast furnace, if the furnace wall refractory in front of the stave falls off, the stave is exposed inside the furnace and excessively cools the inside of the furnace. It is considered that these become factors that hinder stable operation and cause disturbance of the in-furnace condition due to the removal of refractory materials in the middle of the life of the furnace body (about 5 to 6 years).

Therefore, conventionally, in stave blast furnaces, cooling platen blast furnaces and the like, the following repairing methods have been used for the brickwork portion above the shaft, the furnace wall abdominal portion and the like.

A method of repairing by spraying on the front surface of the remaining bricks at the brick falling-off portion, using an amorphous spray material made of the same material as the refractory bricks of the furnace wall.

A method in which a block of a water cooling pipe with studs is attached to a damaged portion of a furnace wall, and a refractory material is sprayed on the front surface of the furnace wall for repairing.

A method of repairing the furnace wall by attaching a fired refractory plate, a stave cooler, or the like, and press-fitting and filling an irregular-shaped refractory from the outside of the furnace through a pressurizing port into the back surface of the gap between the remaining bricks.

However, the above-mentioned repair methods have the following drawbacks.

The method (1) is just an emergency measure, and since the spraying work is performed from a distance, the material loss is large (20
~ 30%), the workability is extremely poor, the durability of the repaired part is low (about 1 to 4 months), and the repair frequency is high. In this method, since the spray material is not repaired by spraying on the cooling pipe, it becomes porous and the strength is inferior, so the wear resistance is low and wear damage easily occurs. Deformation / wear will cause water leakage, and the sprayed refractory will fall off. Therefore, this method also has poor durability (about 2 to 6 months) and is expensive to repair.

The method of (1) is to press and fill the amorphous refractory into the gap between the remaining bricks. However, since the firing refractory plate is a fired product of the irregular refractory, the machine at the portion fixed to the furnace wall It has low mechanical strength, poor wear resistance, and is easily damaged, resulting in poor durability. Further, in the stave cooler, when the front refractory material is worn or dropped, the furnace inner front surface is exposed, and the furnace interior contents in the relevant portion are excessively cooled, so that so-called deactivation progresses. , There is a risk that the conditions inside the furnace will fall into a disorder.

Further, as a problem common to both the above and the above, since it is a water cooling system, an expensive pumping equipment with a high head is required, and a water leak detecting device is also required, so that the equipment cost and running cost are very high. There are drawbacks such as.

[0011]

Therefore, the present invention is
By solving the problems in these conventional repair methods and using a repair panel that is non-water-cooled and has both durability under high temperature and mechanical strength in installation, high durability and long life can be achieved. An object of the present invention is to provide a furnace wall repair method for a blast furnace capable of forming a furnace wall at a low facility cost, and a panel composed of a functionally graded material having a thermal stress relaxation function suitable for use in this repair method and the like. It is what

[0012]

The present invention has a thermal stress relaxation function and a high degree of mechanical characteristics, which are attracting attention as a heat shield tile in a space shuttle and a next-generation hypersonic vehicle under an ultrahigh temperature environment. The idea is to use a non-water-cooled functionally graded panel that also has the following features.

That is, the method of repairing a furnace wall of a blast furnace according to the invention of (1) is such that an alumina-based or non-oxide-based ceramic material and a metal material such as cast iron are formed on the inner surface of the furnace wall where the refractory brick is dropped and / or damaged. A panel made of a composite material of, and a panel made of a functionally graded material having a thermal stress relaxation function between both surfaces, in which the composition ratio continuously transitions from one surface side to the other surface side, and the panel is attached. It is characterized by injecting and filling an adhesive amorphous refractory into the gap between the inner wall of the furnace and the inner wall of the furnace wall and hardening it.

The panel having a thermal stress relaxation function according to the invention (2) is a panel made of a composite material of an alumina-based or non-oxide ceramic material and a metal material such as cast iron. One side of the panel It is characterized in that the composition ratio continuously transitions from one surface side to the other surface side.

Specific examples of the present invention and their effects will be described below with reference to the drawings. First, the left cross section of FIG. 1 shows the state of the residual bricks 4 and the worn stave cooler 5 in the damaged part of the furnace wall of the blast furnace, and the right cross section of FIG. 1 shows the repaired method according to the present invention for the damaged part of the furnace wall. State
Shown respectively. In the left cross section, the chain line 3 is the furnace wall profile in a sound state. FIG. 2 is an enlarged view of a main part in a collected state.

Referring now to FIGS. 1 and 2, when repairing a damaged portion of the blast furnace wall by the method of the present invention,
First, reduce the charge 6 to a level below the repair site,
Take a break. After that, a plurality of manholes 12 provided around the gas collecting mantel 2 on the upper part of the furnace body skin 1 are opened, and the remaining bricks 4 in the range where the panel 7 of the damaged part of the furnace wall is installed.
And the surface of the worn cooler 5 is washed by an appropriate method (not shown) such as air blow or water spray. In this case, prior to cleaning, from the outside of the furnace to the furnace body iron shell 1, the remaining bricks 4, or the worn stave cooler 5, at positions corresponding to a plurality of panel locking portions 8-1 of the panel 7 described later, The bolt mounting hole 8-2 is opened by a core boring machine.

The panel 7 used in the present invention is provided with a plurality of panel engaging portions 8-1 projectingly provided on the side surface of the furnace wall. In order to bring the panel 7 to the damaged portion of the furnace wall, the panel mounting bolt 8 is suspended in the panel locking portion 8-1, and the panel 7 is attached by the winch 15 and the wire rope 14 via the wire sheave 15. Hanging in the furnace,
When the panel 7 reaches a predetermined position, the panel mounting bolt 8 suspended from the outside of the furnace through the bolt mounting hole 8-2 is hooked on the panel locking portion 8-1 to draw the panel 7 toward the furnace wall surface side. A fixing bolt 8 is tightened and fixed at a predetermined position of the furnace body iron shell 1. At this time, the panel mounting hole 8-2
The bolt cap 8-3 is welded to the furnace shell 1 so as not to leak gas from the furnace body. Further, it is preferable to dispose the end seal plate 11 around the mounting position of the panel 7 so as to prevent the refractory from leaking when the highly adhesive amorphous refractory is press-fitted.

When the panel 7 is fixed to the damaged portion of the furnace wall, the remaining bricks 4 or the worn stave cooler are set so that the inner surface of the furnace of the panel 7 is substantially equal to or close to the profile 3 at the time of soundness. It is necessary to adjust the thickness of the gap with the surface of No. 5. This is because if there is a step on the inner surface of the furnace wall after repairing, a mixed layer of coke and sinter is formed when the raw material descends, the balance of the charge is disturbed, and the rising reducing gas flow is disturbed. , Because it may adversely affect the operation.

If the degree of damage is relatively small and the required thickness of the gap between the panel 7 and the surface of the remaining brick 4 or the worn stave cooler 5 can be substantially filled with the thickness of the panel 7 itself, It is possible to select whether the panel 7 is tightened and fixed by the mounting bolts 8 or a small amount of the highly adhesive amorphous refractory described below is press-fitted / filled into the gap and cured. When the damage is so severe that the gap of the panel 7 cannot be filled up, the highly adhesive amorphous refractory 10 such as phenol resin, amino resin, epoxy resin, siloxane resin or the like is filled in the gap. It is necessary to press-fill and harden a mixture of a refractory material and a resin having high adhesiveness, preferably high heat resistance. When press-fitting / filling the highly adhesive amorphous refractory, preferably the furnace body iron shell 1, prior to the cleaning operation,
The press-fitting nozzle 9 is bored in the remaining brick 4 or the worn stave cooler 5. The highly adhesive amorphous refractory 10 is press-fitted after the panel 7 is fixed at a predetermined position by the mounting bolt 8. In this case, the end seal plate 11 acts to prevent the press-fitting refractory from leaking. Further, the press-fitting of the highly adhesive amorphous refractory material 10 requires that the gap be filled almost completely. This is because if there are gaps or cavities, high-temperature gas, so-called back wind, flows in the gaps and the mounting bolts 8 and the panel locking portions 8-1
This is because there is a risk that the strength will be reduced or broken by heat and the panel 7 will fall off. As the end seal plate 11, a plate having a high heat resistance such as a steel plate or a ceramic plate is preferable.

The side wall B of the furnace wall of the panel 7 of the present invention is made of cast iron 7
Since it is made of -1, the protruding portion of the panel locking portion 8-1 can be easily manufactured by an appropriate method such as casting, screwing, welding, etc., and sufficient mechanical strength is secured. be able to. Therefore, the panel 7 is attached to the bolt 8
Can be firmly and tightly fixed.

Next, the functionally graded panel 7 having a thermal stress relaxation function used in the present invention will be described.
The area where this panel 7 is installed is about 60 during blast furnace operation.
Since it is placed in an environment where the temperature is high at 0 to 1,000 ° C. and the temperature changes drastically, a large amount of thermal stress is generated. Therefore, the conventional fired refractory plate and stave cooler could not be used.

On the other hand, the panel 7 of the present invention has a macro stress-relieving function in which different functions such as heat shield characteristics on the heating side and mechanical characteristics as a structure on the cooling side are shared. It is a homogeneous structure. Moreover, this structure is a functionally graded type in which the structure made of different materials having respective functions does not substantially form an interface so that the structure continuously transitions from the heating side to the cooling side. ..

In order to manufacture such a panel 7,
It is necessary to simultaneously achieve both (1) optimization of the heat shield characteristics and mechanical characteristics and (2) optimization of the thermal stress relaxation function, and here, when creating the panel 7 of the present invention, There is difficulty.

FIG. 3 schematically shows a cross section of an example of the panel 7 of the present invention. Panel 7 is on the heating side (inside the furnace) surface A
Is substantially composed of an alumina-based or non-oxide-based ceramic material, and the cooling side (outside of the furnace) surface B is substantially composed of a metal material. Between both surfaces, the ceramic is provided from the heating side to the cooling side. The density of the material is gradually lowered, and conversely, the density of the metal material is gradually increased, and the intermediate portion C has a functionally graded structure forming a composite phase of the ceramic material and the metal material. As a result, a thermal stress relaxation function of appropriately dispersing local thermal stress generated inside the panel 7 under the temperature gradient of heating and cooling of the furnace body is achieved, and the cooling side to which the panel 7 is attached becomes a high-strength metal material. Therefore, it is possible to have the necessary mechanical characteristics.

The cross-sectional macro composition in the thickness T direction of this functionally graded panel 7 is schematically shown in FIG. 4 (a). In FIG. 4A, the horizontal axis AB indicates the thickness T direction of the panel 7, and the vertical axis indicates the ceramic 7-2 (broken line) and the metal material 7-1.
The relative component amount of (solid line) is shown. Also, Fig. 4 (b) shows
FIG. 3 is a diagram conceptually showing the thickness T of the panel 7 and the temperature distribution in the horizontal axis direction when the furnace temperature reaches about 1200 ° C.
The vertical axis represents temperature. The broken line a in the figure indicates the temperature when the panel 7 is entirely made of a metal material, that is, cast iron, and the temperature t _B on the heating side _A to the cooling side _B has a linear temperature gradient. On the other hand, when the functionally graded panel 7 having the thermal stress relaxation function according to the present invention is used, a parabolic temperature gradient is exhibited as shown by the solid line A in the figure. This is because the intermediate range C between the A surface and the B surface forms a composite phase of the ceramics 7-2 and the metal material 7-1, and the temperature gradient (fall) is relaxed, and the temperature difference (fall) even under the temperature fluctuation of heating and cooling. If the value is small, the generated thermal stress is greatly reduced and the thermal stress relaxation function is fulfilled.
The generation of cracks is significantly suppressed. Further, even if the panel 7 is gradually worn from the inside of the furnace and the thickness T becomes thin, since the functionally graded material structure has a continuous transition in the thickness direction, the thermal stress relaxation function described above can continue. it can.

As the ceramic constituting the panel 7,
Alumina (Al ₂ O ₃ ) or silicon carbide (Si
C), silicon nitride (Si ₃ N ₄ ) molybdenum silicide (MoS
Non-oxide materials such as i ₂ ) are excellent in low heat transfer characteristics, heat resistance, oxidation resistance when exposed to a high temperature gas flow, and wear resistance characteristics that can cope with the fall of furnace interior contents. It is preferable from the point of view, and as a metal material, gray cast iron (JISG550) has a proven track record in blast furnace stave coolers and the like.
1) FC150, spheroidal graphite cast iron (JISG5502) F
CD440 and the like are preferable.

Ceramic material 7 inside the panel 7
The shape, diameter, arrangement state, and the like of 2 can be appropriately selected in consideration of the thermal relaxation characteristics required for the panel 7 depending on the operating conditions of the blast furnace and the mechanical characteristics on the cooling side. Therefore, although a ceramic material having a circular cross section is shown in FIG. 3, the present invention is not limited to this, and the cross section is selected from polygons such as triangles, squares, pentagons, and hexagons, and oval shapes such as ellipses. In addition, it may have a different shape in consideration of the adhesiveness to the molten metal, and may be continuous or discontinuous in the direction orthogonal to the section A-B in FIG.

As for the arrangement of the ceramic material 7-2, in addition to the zigzag arrangement shown in FIG. 3, a lattice arrangement seen from the direction A (or direction B) of FIG. Yes, some ceramic materials 7-2
It is also possible to arrange them after combining them in a grid pattern in advance.

The ceramic material 7-2 in the panel 7
The diameter of is selected in consideration of the required thermal and mechanical characteristics according to the shape, arrangement state, and the like.

Now, a method for manufacturing the panel 7 having the thermal stress relaxation function of the present invention will be described. FIG. 5 shows a typical manufacturing example. Here, (a) is a ceramic material 7-2
3B is a cross-sectional view as seen from the horizontal direction of FIG. 3B, and FIG. 3B is a cross-sectional view as seen from the vertical direction of the ceramic material 7-2.

As shown in FIG. 5, a rod-shaped ceramic material 7 having different diameters is provided inside a sand mold 17 having an appropriate shape and size.
-2, assuming that the inner lower surface of the sand mold 17 is the heating-side surface A, and the diameter is gradually reduced from the heating side in the thickness T direction of the panel 7 (in the order of A → A → U → E), the ceramic material 7-2 is provided with a gap so that the density becomes appropriate. Here, when pouring the molten metal 7-1 into the sand mold 17, the pouring pressure or the like prevents the ceramic material 7-2 from moving and floating, as shown in FIG. Both ends of the rod-shaped ceramic material 7-2 are embedded in the inner side surface of 17. The embedded dimension L can be arbitrarily set as long as the ceramic material 7-2 can be sufficiently fixed. At this time, in combination with the embedding of both ends of the ceramic material 7-2, the vicinity of the central portion of the width dimension W is cleaned with a cleaning rod (wire).
Each ceramic material 7-2 may be connected and fixed by (not shown).

The size (T × W × L) of the panel 7 is typically, for example, 100 to 150 mmT × 1000 mmW.
It is suitable to be about 1500 mmL, but it can be appropriately selected in consideration of its transportation, intake, installation work on the inner surface of the furnace wall, and the like.

[0033]

According to the present invention described in detail above, the panel according to claim 2, that is, the panel used for repairing the furnace wall has a ceramic material having both durability under high temperature and mechanical strength in installation. Since it is composed of a composite of high-strength metal material, it has a thermal stress relaxation function and can appropriately suppress the heat load of the furnace body, and the durability of the inner wall of the furnace wall after repair is high and the repair frequency is high. Can be significantly reduced,
In addition, the life of the furnace body can be extended. Moreover, since the present invention is a non-water-cooling type, which is a complete dry type that does not require a cooling water pipe, a high-lift pump, etc., it is possible to greatly reduce the equipment cost as compared with the conventional method, and it is economical and energy saving. It is also advantageous in terms of aspects. Furthermore, since the refractory which is press-fitted / filled in the gap between the panel and the remaining brick or the worn stave cooler is a highly adhesive amorphous refractory, it is possible to obtain an extremely strong and long-life protective wall.

As described above, since the blast furnace wall repaired by the present invention can be reproduced in the initial sound profile,
It is possible to improve operability such as productivity improvement and reduction of fuel ratio without causing down-modulation of the charge after repair and turbulence of gas flow. Further, the panel having the function of relaxing the thermal stress is effective for repairing the furnace wall and for the location where the thermal stress due to the temperature difference acts.

[Brief description of drawings]

FIG. 1 is a schematic view showing a state of a blast furnace before and after repair according to the present invention.

FIG. 2 is an enlarged cross-sectional view of the main part of the furnace wall after repairing according to the present invention.

FIG. 3 is a cross-sectional view showing an example of the panel of the present invention.

FIG. 4 is a schematic view showing a cross-sectional macro composition in the thickness direction of the panel of the present invention.

FIG. 5 is a cross-sectional view showing an example of the method for manufacturing the panel of the present invention.

[Explanation of symbols]

 1 Furnace iron shell 2 Gas collection mantel 3 Furnace wall profile in sound condition 4 Remaining bricks 5 Worn stave cooler 5-1 Cooling pipe 6 Charge 7 Panel 7-1 Metal material 7-2 Ceramic material 8 Panel mounting bolt 8-1 Panel locking part 8-2 Bolt mounting hole 8-3 Bolt cap 9 Press-fit nozzle 10 Highly adhesive amorphous refractory 11 End seal plate 12 Manhole 13 Furnace deck 14 Wire rope 15 Winch 16 Wire sheave 17 Sand type

Claims (2)

[Claims] 1. A method for repairing a furnace wall of a blast furnace, wherein a composite material of an alumina-based or non-oxide ceramic material and a metal material such as cast iron is used for the inner surface of the furnace wall where the refractory brick is dropped and / or damaged. In this panel, the composition ratio continuously transitions from one side of the panel to the other side of the panel, and a panel composed of a functionally graded material having a thermal stress relaxation function between both sides is attached to the panel and the inner surface of the furnace wall. A method for repairing a furnace wall of a blast furnace, characterized by injecting and filling an adhesive amorphous refractory into the gap of and hardening it. 2. A panel made of a composite material of an alumina-based or non-oxide ceramic material and a metallic material such as cast iron, the composition ratio of which continuously transitions from one side of the panel to the other side of the panel. A panel made of a functionally graded material having a thermal stress relaxation function.