JP2014218420A - Vertical lime firing furnace cooling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vertical lime firing furnace cooling structure which is effective for improving endurance of refractory materials on an inner cylindrical wall lower end peripheral edge and on near a connection part of a vertical lime firing furnace.SOLUTION: An air cooling jacket 5 having an opening hole on a top part of a steel shell surface is embedded on a back part cooling end side of the refractory material in an inner cylindrical wall 3 of the vertical firing furnace. In addition, the air cooling jacket is communicated with an annular air cooling jacket 8 at the opening hole part. By providing the opening hole on the top part of the air cooling jacket 5, cooling by autonomous ventilation based on the heat syphon principle becomes possible.

Description

The present invention relates to a cooling structure for a vertical lime firing furnace that cools a refractory in the vicinity of the connection portion of the furnace lid and the lower portion of the inner cylindrical wall of the vertical lime firing furnace.

The vertical lime firing furnace 10 includes a furnace body 10b and a preheating chamber 10a. The furnace body is usually provided with a combustion device 16 in the center of the ceiling. Below the furnace main body ceiling 7, there is an annular hearth 11 having a surface extending in the horizontal direction and having a dropping hole in the center. A cylindrical outer cylinder wall 2 stands on the outer periphery of the hearth. There is an inner cylinder wall 3 concentrically with the outer cylinder wall. A portion surrounded by the hearth, outer cylinder wall, and inner cylinder wall is a preheating chamber. The upper end of the preheating chamber is covered with a preheating chamber lid 9. The preheating chamber lid is connected to the raw material supply pipe 17.

The preheated lime falls to the furnace main body 10b and is finally fired, and is discharged from the lowermost part of the main body.

In the vicinity of the connecting portion 1 of the vertical calcination furnace formed in this way and the peripheral edge 4 at the lower end of the inner cylinder wall, the refractory is severely worn by high temperatures, thermal cycles, and wear.

In such a vertical lime firing furnace, as known from Patent Document 1, the durability of the refractory is improved by cooling the connection portion and the lower portion of the inner cylinder wall by an annular duct and attached equipment. It is illustrated.

Usually, the annular duct (annular air cooling jacket) 8 is divided in the circumferential direction and connected by a flange. A metal anchor 6 is arranged on the outer surface (furnace inside) of the annular duct to hold the castable refractory.

In addition, various attempts have been made to improve and improve the material of the refractory in this part. At present, a typical brick suspension structure is used for the connecting portion, and a castable refractory is used for the lower portion of the inner cylinder wall.

Generally, in order to improve the durability of the refractory, the furnace wall is widely cooled. Patent Documents 2, 3, and 4 disclose a cooling structure of the furnace wall of an incinerator using an air cooling jacket (another name box or box).

JP2012-112548 JP2003-14217 JP2004-53166 JP 2005-308279 A

However, in the cooling method disclosed in Patent Document 1, the connection portion can be cooled and has good durability, but the lower portion of the inner cylinder wall is not sufficiently cooled and its durability is short. The castable refractory near the lower part of the inner cylinder wall peeled off in a short period of time, causing the iron skin or annular duct to become red hot, leading to the suspension of operations for repair. Even if the operation is not stopped, the flange portion of the iron skin is distorted, a gas leak is generated, and a large amount of cooling air is required, causing a problem of increasing the power for the blower.

In each of the cooling methods disclosed in Patent Documents 2, 3, and 4, only one surface of the cooling jacket is in contact with the refractory, and cooling efficiency is limited. The annular duct disclosed in Patent Document 1 can be said to be similar to Patent Documents 2, 3, and 4 in that it has only one contact surface with the refractory.

Accordingly, an object of the present invention is to provide a cooling structure for a vertical lime firing furnace that is effective for improving the durability of the refractories near the bottom of the inner cylinder wall and the connecting portion of the furnace lid of the vertical lime firing furnace. is there.

The cooling structure of the vertical lime baking furnace according to the first invention that solves the above-described problem embeds an air cooling jacket 5 having an opening hole 12 on the back cold end side of the inner cylindrical wall of the vertical lime baking furnace, Cooling air is allowed to flow in the air cooling jacket.

In the cooling structure for a vertical lime baking furnace according to the second invention for solving the above-described problem, an air cooling jacket 5 having an opening hole 12 is embedded in the cold end side of the inner cylindrical wall 3 of the vertical lime baking furnace. The air-cooling jacket is connected to and communicated with the annular air-cooling jacket 8 through an opening hole so that the cooling air of the annular air-cooling jacket flows through the air-cooling jacket.

According to the cooling structure of the vertical lime baking furnace according to the first invention, an air cooling jacket having an opening hole is embedded in the back cold end side of the inner cylindrical wall refractory of the vertical lime baking furnace, The refractory is cooled satisfactorily by flowing cooling air through the refractory.

Since the air-cooling jacket has an opening hole in the upper part, the air-cooling jacket is autonomously ventilated by the principle of a thermosyphon, so that the cooling efficiency is high. As shown in FIG. 2, the cooling air 18a descends along the jacket wall while cooling the inner cylindrical wall castable refractory, changes direction at the bottom, rises while cooling the back surface of the connecting brick 1, and is heated. The air 18b is returned to the annular air cooling jacket 8.

In the case of air-cooled jackets disclosed in Patent Documents 2, 3, and 4, the jacket is in contact with the refractory on one side, whereas the air-cooled jacket of the present invention is in contact with the refractory on multiple sides or curved surfaces. So the contact area is large. As a result, the cooling efficiency is high.

The air-cooling jacket of the present invention has a higher stress absorption performance than the conventional single-plate structure due to the effect of the shape, so that thermal distortion of the flange portion can be prevented and gas leakage can be reduced.

As a result, the life of the inner cylinder wall refractory of the vertical lime firing furnace is extended, and the repair interval is increased.

According to the cooling structure of the vertical lime firing furnace according to the second invention, since the air cooling jacket 5 is connected to the annular air cooling jacket 8, a large amount of cooling air is exchanged, and the cooling effect of the refractory is further increased. .

It is a longitudinal cross-sectional schematic diagram which shows the principal part of the vertical lime baking furnace provided with the cooling structure which concerns on 1st Example of this invention. It is the schematic explaining the flow direction of the cooling air in the cooling structure which concerns on 1st Example of this invention. It is a longitudinal cross-sectional schematic diagram which shows the principal part of a vertical lime baking furnace provided with the conventional cooling structure. It is the schematic side view seen from the furnace outer side of the cooling jacket which has the opening hole which concerns on 1st Example of this invention. It is the schematic side view seen from the furnace of the cooling jacket which has an opening hole concerning the 1st example of the present invention. It is a horizontal section schematic diagram of a cooling jacket which has an opening hole concerning the 1st example of the present invention. It is explanatory drawing which shows the detail of the cooling jacket which concerns on the 1st Example of this invention. 1 is an overall schematic diagram of a vertical lime baking furnace provided with a cooling structure according to a first embodiment of the present invention.

Below, the best form for implementing the cooling structure of the vertical calcination furnace which concerns on this invention is demonstrated concretely based on an Example.

In FIG. 8, the outline of the whole vertical lime baking furnace which concerns on this invention was shown. FIG. 1 is a view in the vicinity of a preheating chamber of a vertical lime baking furnace, and is a schematic longitudinal sectional view of a cooling structure according to a first embodiment of the present invention. FIG. 2 is an enlarged view showing a main part of the cooling structure according to the first embodiment of the present invention. FIG. 3 is the same position as FIG. 1 and shows a conventional cooling structure. The connecting portion 1 and the inner cylinder wall lower portion 4 are cooled by passing cold air through the annular air cooling jacket 8. 4, 5, 6, and 7 are views showing details of the air-cooled jacket metal fitting provided for the cooling structure of the vertical lime baking furnace according to the present invention.

As shown in FIG. 1, an air cooling jacket 5 according to the present invention was embedded on the back cold end side of the inner cylindrical wall portion of the preheating chamber of the vertical lime baking furnace. As shown in FIG. 4, the air cooling jacket has a plurality of opening holes 12 on the upper side. The opening hole portion is connected to and communicated with the annular air cooling jacket 8.

Although FIGS. 1, 2, and 7 show wedge-cooled air-cooling jackets, they may be rectangular, elliptical, circular, or the like.

As shown in FIG. 6, the air-cooling jacket according to the present invention is divided into blocks having an appropriate length in the circumferential direction of the vertical lime baking furnace in consideration of handling during installation. A flange 13 and a bolt hole 14 are provided at the end of each block, and each block is connected with a bolt and a nut.

The air cooling jacket of the present invention is preferably divided into small chambers by a partition plate 15 as shown in FIGS. This is because the flow of the cooling air 18a and the heated air 18b is made into a laminar flow to improve the heat exchange efficiency. The partition plate also functions to reinforce the jacket. The number of partition plates is preferably about 3 or 4 for each block. The length in the circumferential direction of the chamber of the air cooling jacket is preferably about 200 mm. The radial thickness of the chamber is preferably about 50 mm. The higher the vertical height of the air cooling jacket chamber, the greater the cooling effect. However, it is usually determined in consideration of the amount of cooling air, the furnace temperature, the thickness of the refractory, the thermal conductivity of the refractory, and the like. The height of the opening hole is preferably the same as the thickness of the chamber. This is to make the air flow laminar.

When the present invention was applied to an actual machine in the form shown in FIG. 1, the durability of the castable refractory on the inner cylinder wall was improved by about 50% compared to the conventional form shown in FIG. It was evaluated as an effect of cooling effect improvement.

In addition, the power consumption for the blower was reduced by about 10% by applying the present invention. It was evaluated that the distortion of the iron shell and flange decreased, and the amount of leakage of the gas in the furnace into the annular air-cooled jacket decreased. As a result of the reduction in gas leakage, the amount of fuel used in the vertical lime kiln body has also been reduced.

As clearly shown in FIG. 1, the air-cooling jacket of the present invention is also effective for cooling the refractory in the connection portion.

The cooling structure of the present invention is effective for cooling the refractory in the vicinity of the connection portion and the lower part of the inner cylinder wall, which is the durability neck of the vertical calcination furnace. It is also effective for saving cooling power and fuel for operation, and is considered to have great industrial applicability.

DESCRIPTION OF SYMBOLS 1 Connection part 2 Outer cylinder wall 3 Inner cylinder wall 4 Lower peripheral edge 5 Lower air-cooling jacket 6 Metal anchor 7 Furnace body ceiling 8 Annular air-cooling jacket 9 Preheating chamber lid 10 Vertical lime firing furnace 10a Preheating chamber 10b Furnace body 11 Annular hearth 12 Opening hole 13 Flange 14 Bolt hole 15 Partition plate 16 Combustion device 17 Raw material supply pipe 18a Cooling air 18b Heated air

Claims (2)

A cooling structure for a vertical lime firing furnace, characterized in that an air cooling jacket having an opening hole in the upper part of the iron skin is embedded on the back cold end side of the inner cylindrical wall refractory of the vertical lime firing furnace. 2. The cooling structure for a vertical lime baking furnace according to claim 1, wherein the cooling structure for the vertical lime calcining furnace is in communication with the annular jacket at the opening hole.

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