JP3584982B2 - Water cooled wall - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a water-cooled furnace wall used for a furnace body such as a waste melting furnace, and more particularly to a water-cooled furnace wall lined with a castable refractory layer.
[0002]
[Prior art]
The water-cooling furnace wall has a structure in which a water-cooling jacket 2 is provided outside the steel shell 1 to circulate cooling water as shown in FIG. 6, and a castable refractory layer 3 is provided inside the steel shell 1 in a waste melting furnace or the like. The lining is usually used. As is well known, a large number of holding hooks 4 are welded to the inner surface of the steel shell 1 at a pitch of, for example, 100 to 500 mm, and when the castable refractory is sprayed, these holding hooks 4 exert an anchor effect to castable refractory. The material layer 3 is held firmly.
[0003]
The castable refractory layer 3 is stable under high temperature conditions, but when molten slag exists in the furnace, the castable refractory layer 3 is gradually eroded. However, if the temperature rise of the castable refractory layer 3 is suppressed by using the water-cooled jacket 2, the self-coating layer 5 made of slag is stably formed on the surface of the castable refractory layer 3, and the molten slag becomes molten. Erosion is suppressed because direct contact with is prevented.
[0004]
However, while the temperature rise of the castable refractory layer 3 can be effectively suppressed in a portion where the holding hook 4 is provided, the heat transfer effect of the holding hook 4 is not exerted in an intermediate portion of the holding hook 4, so that the castable refractory material is not provided. The effect of suppressing the temperature rise of the layer 3 is reduced. As a result, as shown in FIG. 7, a stable self-coating layer 5 is not formed in the middle portion of the holding hook 4, and there is a problem that the castable refractory layer 3 is eroded and the life of the furnace wall is shortened.
[0005]
In order to solve this problem, the present inventor has also attempted to reduce the pitch at which the holding hooks 4 are attached to the steel shell 1. However, when the holding hooks 4 are densely arranged, the amount of heat transferred from the castable refractory layer 3 to the steel shell increases, so that the amount of heat taken out of the furnace to the cooling water increases, and the thermal efficiency of the entire furnace decreases. Therefore, in order to maintain the inside of the furnace at a predetermined temperature, the amount of fuel used in the burner must be increased, and there is a problem that the operating cost increases.
[0006]
[Problems to be solved by the invention]
The present invention has been made to solve the above-mentioned conventional problems and to provide a water-cooled furnace wall capable of preventing the erosion of the castable refractory layer without causing excessive heat removal from the furnace wall. It is.
[0007]
[Means for Solving the Problems]
The present invention made in order to solve the above-mentioned problem is a water-cooled furnace wall provided with a water-cooling jacket on the outside of a steel shell and a castable refractory layer on the inside, and a castable refractory layer on the inner surface of the steel shell. A large number of holding hooks for holding are arranged, and a large number of heat absorbers shorter than the holding hooks are arranged between these holding hooks. The heat absorber can be a metal hook or a metal coil.
[0008]
The water-cooled furnace wall of the present invention provides a moderate heat-absorbing effect even in the middle portion of the holding hook by arranging a number of heat-absorbing members having a shorter height than the holding hook between the holding hooks. Layers can be formed. Therefore, erosion of the castable refractory layer can be prevented. Moreover, since these heat absorbers are shorter than the holding hooks, no excessive amount of heat is taken out of the furnace and the operating cost does not increase.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described.
FIG. 1 is a sectional view showing an embodiment in which the present invention is applied to a waste melting furnace. Reference numeral 11 denotes a cylindrical primary combustion chamber provided with a main burner 12, and reference numeral 13 denotes a secondary combustion chamber provided with a sub-burner 14. It is. The waste or its incineration ash is blown tangentially from the upper part of the primary combustion chamber 11, and is melted and turned into slag while rotating at a high speed inside the primary combustion chamber 11. The slag is further heated together with the unmelted material in the secondary combustion chamber 13 to become a homogeneous molten slag, and is taken out from the slag discharge port 15. The exhaust gas is taken out from the exhaust gas outlet 16. The furnace wall of this melting furnace is provided with a water-cooled jacket 2 outside a steel shell 1 and a castable refractory layer 3 inside.
[0010]
FIG. 2 is an enlarged sectional view of the furnace wall, in which a large number of holding hooks 4 for holding the castable refractory layer 3 are arranged on the inner surface of the steel shell 1. In this embodiment, the holding hook 4 is formed by forming a stainless steel rod having a diameter of 8 mm into a V shape, and has an opening angle of 60 ° and a height of 70 mm. The holding hooks 4 are welded to the inner surface of the steel shell 1 at a pitch of about 300 mm. Note that the shape of the holding hook 4 does not necessarily have to be V-shaped, but may be an appropriate shape such as Y-shaped. The castable refractory layer 3 is firmly held by these holding hooks 4.
[0011]
At a middle position of these holding hooks 4, a number of heat absorbing bodies 6 shorter than the holding hooks 4 are arranged. In FIG. 2, the heat absorber 6 is a stainless steel V-shaped hook having a diameter of 8 mm and a height of 45 mm. FIG. 3 is a diagram showing an example of the arrangement of the V-shaped hook and the holding hook 4 as the heat absorber 6, and the heat absorber 6 is arranged obliquely between the holding hooks 4. The heat absorber 6 increases the amount of heat transferred from the castable refractory layer 3 to the steel shell 1 and cools the castable refractory layer 3 to help form a stable self-coating layer 5.
[0012]
In this example, the hook as the heat absorber 6 has a height that is ２ of the height of the holding hook 4. If the height of the heat absorber 6 is too high, it becomes the same as when the holding hooks 4 are additionally provided, and the amount of heat taken out from the furnace wall increases. Conversely, if the height of the heat absorber 6 is too low, the ability to cool the castable refractory layer 3 will decrease. When the thickness of the holding hook 4 is the same as that of the holding hook 4, the height of the hook as the heat absorbing body 6 is preferably about 50 to 75% of the holding hook 4.
[0013]
By arranging a large number of heat absorbers 6 shorter than the holding hooks 4 at the intermediate positions of the holding hooks 4 as described above, the heat from the castable refractory layer 3 to the steel shell 1 can be maintained at the intermediate positions of the holding hooks 4. The movement is promoted, and a stable self-coating layer 5 can be formed on the surface of the castable refractory layer 3, as shown in FIG. 4, and the erosion of the castable refractory layer 3 is prevented. For this reason, the life of the furnace wall can be extended more than the conventional furnace wall without the heat absorber 6. Also, the amount of heat transfer from the castable refractory to the steel shell 1 is smaller than when the holding hooks 4 are added, and the heat in the furnace is not excessively taken out.
[0014]
FIG. 5 shows an example in which a metal coil is used as the heat absorber 6. In this case, a larger area than the hook can be cooled slowly. The heat absorber 6 is not necessarily limited to a hook or a coil, but needs to have a structure that can be brought into close contact with the castable refractory layer 3.
[0015]
【Example】
A holding hook having a height of 70 mm is arranged at a pitch of 200 mm on the inner surface of a steel shell constituting a water-cooling furnace wall of the waste melting furnace, and a heat absorbing hook having a height of 45 mm is arranged between these holding hooks. A castable refractory was sprayed from above to form a castable refractory layer having a thickness of 100 mm. For comparison, a portion having a conventional structure without a heat absorbing hook was also formed. After a continuous operation for 300 days at a furnace temperature of 1400 ° C., the thickness of the castable refractory layer was measured.
[0016]
As a result, the intermediate position of the holding hook was severely eroded in the conventional structure, and the thickness of the castable refractory layer was reduced from the original 100 mm to 40 mm. However, in the portion where the heat-absorbing hook was arranged, erosion was small even in the middle position of the holding hook, and the thickness of the castable refractory layer was reduced from the initial 100 mm to only 78 mm. In addition, the increase in the amount of heat taken out of the furnace wall due to the arrangement of the heat-absorbing hook is negligible, and the fuel consumption of the burner required to maintain the furnace temperature at 1400 ° C. It was no different from a waste melting furnace.
[0017]
【The invention's effect】
As described above, the water-cooled furnace wall of the present invention has a large number of heat sinks shorter than the holding hooks between the many holding hooks for holding the castable refractory layer. Erosion of the castable refractory layer can be prevented without causing excessive heat to be taken out of the refractory. For this reason, there is an advantage that the life of the furnace wall can be extended twice or more as compared with the conventional case, and the operating cost does not increase.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment in which the present invention is applied to a waste melting furnace.
FIG. 2 is an enlarged sectional view of a furnace wall.
FIG. 3 is a diagram showing an example of arrangement of a V-shaped hook and a holding hook 4 as a heat absorber.
FIG. 4 is a cross-sectional view showing an eroded state of the castable refractory layer.
FIG. 5 is an enlarged sectional view of a furnace wall showing an example using a coil as a heat absorber.
FIG. 6 is an enlarged sectional view showing a conventional furnace wall.
FIG. 7 is a cross-sectional view showing a conventional erosion state of a furnace wall.
[Explanation of symbols]
1 steel jacket, 2 water cooling jacket, 3 castable refractory layer, 4 holding hook, 5 self-coating layer, 6 heat sink, 11 primary combustion chamber, 12 main burner, 13 secondary combustion chamber, 14 auxiliary burner, 15 slag discharge Exit, 16 exhaust gas outlet

Claims (3)

A water-cooled furnace wall provided with a water-cooling jacket on the outside of the steel shell and a castable refractory layer on the inside, and a large number of holding hooks for holding the castable refractory layer on the inner surface of the steel shell, and these A water-cooled furnace wall, wherein a number of heat absorbers shorter than the holding hooks are arranged between the holding hooks. The water-cooled furnace wall according to claim 1, wherein the heat absorbing body is a metal hook. The water-cooled furnace wall according to claim 1, wherein the heat-absorbing body is a metal coil.

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