JPH10274481A - Method for removing deposit on inner wall face of rotary kiln - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for removing deposit on an inner wall face of a rotary kiln, capable of minimizing heat loss required for deposit-removing work according to extremely simple operation and simultaneously capable of operating the kiln stably and continuously. SOLUTION: In removing a deposit on an inner wall face of a rotary kiln, a heat load in the kiln is more increased than that at the time of ordinary burning upon regulating a combustion rate of a burner for burning, whereby the deposit on the inner wall face of the kiln is melted to be separated therefrom. Then, by rapidly decreasing the heat load of the burner for burning, the surface of molten clinker thus separated is cooled and hardened, and the deposit is discharged and removed from inside the rotary kiln as clinker.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing deposits on an inner wall surface of a rotary kiln, and more particularly, to removing deposits formed on an inner wall surface of a rotary kiln when a raw material to be fired such as a cement material is fed into a rotary kiln and fired. How to do it.

[0002]

2. Description of the Related Art Conventionally, in the operation of a rotary kiln (hereinafter referred to as a kiln) for firing industrial raw materials such as cement raw materials, when the raw materials reach a kiln firing zone, a part of the raw materials adheres and grows little by little on the inner wall surface of the kiln. A so-called coating (adhered matter) is formed in the shape. If the growth of the deposits continues, not only will the movement of the raw materials be hindered, but in the worst case, ventilation will be impeded, making it impossible to operate the kiln smoothly, which will hinder continuous operation. Therefore, it is necessary to remove the deposits at regular intervals, such as a method of temporarily stopping the operation of the kiln and removing the deposits with an industrial gun,
After the kiln is cooled, it is removed by a human sea using an air hammer or a metal push rod.

[0003] In recent years, as a removal technique in consideration of the continuous operation of the kiln, a cutting device is inserted from the discharge port of the kiln and hot matter is removed by using the rotational force of the kiln. It has been devised to remove the deposit by a method of impact destruction of the deposit by spraying.

[0004]

The method using a cutting device or high-pressure water is intended to reduce the heat loss caused by stopping the kiln and to stably operate the kiln continuously. Because the strength of the deposit itself and the adhesive strength with the kiln refractory are constantly changing due to fluctuations in raw material components and changes in firing temperature and other conditions.
At present, a sufficient effect of removing extraneous substances has not been obtained. That is, when a cutting device is used, there is a drawback that if the strength of the deposit exceeds the limit strength of the cutting device, it cannot be used. Further, in the case of high-pressure water, since the work is performed manually, the pressure of the water that can be endured by human power is necessarily limited, and the effect of removing the deposits is limited. At the same time, the length of the high-pressure water injection nozzle is also limited by weight, which limits the range of the removal operation.
Furthermore, when a large amount of water is used at one time, the quality of the material to be fired is deteriorated, burning of the burner is inferior, and the amount of heat is increased.

Therefore, a sufficient removal effect cannot be obtained unless means corresponding to these problems are used. In practice, the kiln is stopped and the conventional removal method using an industrial gun or a human sea is used. The fact is that it is inevitable.

The present invention solves the above-mentioned drawbacks and minimizes the heat loss due to the extraneous matter removal operation by extremely simple operation, and at the same time, removes extraneous matter from the inner wall surface of the rotary kiln which enables stable continuous operation of the kiln. The aim is to provide a method.

[0007]

According to the present invention, there is provided a method for removing deposits on an inner wall surface of a rotary kiln according to the present invention. After adjusting, the heat load in the kiln is increased from that in normal firing, so that the deposits on the kiln inner wall surface are melted and peeled off,
By rapidly reducing the heat load of the firing burner, the exfoliated molten clinker surface is cooled and hardened, and the deposits are discharged and removed from the rotary kiln as a clinker. In addition, when removing the deposits on the inner wall surface of the rotary kiln, the feed amount of the raw material to be fired may be temporarily reduced or stopped, and the position of the firing burner can be changed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for removing deposits on the inner wall surface of a rotary kiln in a cement production facility will be described below as an embodiment of the present invention with reference to the drawings. In FIG.
1 is a kiln, 2 is a firing burner, and 3 is a cooler.
A cement raw material (raw material to be fired) 5 inserted into the kiln 1 from a chute 4 provided at one end 1a of the kiln 1 is fired into a semi-molten clinker by the combustion heat of the firing burner 2. Next, the clinker moves to the other end 1 of the kiln 1.
b, is cooled by the cooler 3, and is ground together with the gypsum in a product process (not shown) to produce cement.

In such a cement production facility, when the cement raw material 5 reaches the sintering zone A of the kiln 1,
A part of the raw material is softened and melted, and grows little by little on the inner wall surface 1c of the kiln to form a deposit 6 in a ring shape. Attachment 6
If the growth of the slag continues, it may hinder the movement of the raw material 5 in the kiln 1 as described above, and may also impede the kiln ventilation.
In the present invention, the amount of combustion of the firing burner 2 is adjusted to remove the deposit 6.

That is, by adjusting the fuel supply amount and the air amount of the firing burner 2 to increase the heat load of the firing zone A as compared with the normal firing, the deposit 6 is melted and the inner wall surface of the kiln is melted. Peel from 1c. For example, the heat load of the fired body zone A is increased by increasing the fuel supply amount by about 30 to 50% and the air amount by about 10 to 30% as compared with normal times, and the attached matter 6 is heated and melted (melted clinker). Next, the firing burner 2 is operated in the reverse manner as described above, that is, the fuel supply amount is reduced by about 30 to 50% and the air amount is reduced by about 10 to 30% as compared with the normal time, so that the heat load in the kiln 1 is rapidly increased. By reducing, the surface of the molten clinker peeled off from the kiln inner wall surface 1c is cooled and hardened.

The hardened clinker rolls in the kiln 1 together with the normal fired clinker while the other end 1
and reaches the cooler 3. After discharging and removing the deposit 6 from the kiln 1 as a clinker, the burning amount of the firing burner 2 is returned to the state at the time of normal firing.

When removing the deposits 6 on the kiln inner wall surface 1c, the amount of combustion of the firing burner 2 is adjusted,
The feed amount of the raw material to be fired (the cement raw material 5) may be temporarily reduced or stopped. Further, as shown in FIG.
In the vertical direction Z, the position of the burning point can be changed, and a local reducing atmosphere can be created to lower the melting point of the deposit 6. In addition, by appropriately combining these operations, such as adjusting the draft inside the kiln 1, it is possible to prevent a decrease in product quality in the work for removing adhering substances and minimize heat loss, thereby effectively reducing the kiln inner wall surface. Deposits can be removed.

[0013]

As described above, according to the present invention, the strength of the adhered substance itself and the adhesive strength to the kiln refractory due to the fluctuation of the raw material component of the adhered substance adhered to the kiln inner wall surface and the change of the firing temperature condition, etc. By being melt-peeled without being affected by the like, it is possible to easily remove the deposits, reduce the heat loss due to the stoppage of the kiln, and enable continuous and continuous operation of the kiln.

Further, in the case of utilizing wastes such as municipal incineration ash and sewage sludge as raw materials in cement production,
Since these raw materials contain a large amount of volatile components such as alkali and chlorine, they significantly promote the adhesion of the kiln inner wall surface and hinder stable continuous operation of the kiln. Frequent deposit removal work due to the stoppage is inevitable. However, according to the present invention, the waste can be released and waste can be greatly utilized as a cement raw material.

Although the method of removing deposits on the inner wall surface of a rotary kiln in a cement manufacturing facility has been mainly described above, the present invention is not limited to firing various industrial raw materials,
It can be effectively applied to waste incineration and the like.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the state of adhesion of the raw material to be fired.

[Explanation of symbols]

 Reference Signs List 1 kiln 1a one end 1b other end 1c kiln inner wall surface 2 firing burner 3 cooler 4 chute 5 material to be fired 6 attached matter A firing zone zone X front-back direction Z vertical direction

Claims (3)

[Claims] When removing the deposits on the inner wall surface of the rotary kiln, the amount of deposits on the inner wall surface of the kiln is increased by adjusting the amount of burning of the firing burner and increasing the heat load in the kiln as compared with normal firing. Melt and exfoliate, then
A method for removing deposits on the inner wall surface of a rotary kiln, characterized in that the heat load of the firing burner is rapidly reduced to cool and cure the peeled molten clinker surface, and that deposits are discharged and removed from the rotary kiln as a clinker. 2. The method for removing deposits on the inner wall surface of the rotary kiln according to claim 1, wherein the feed amount of the raw material to be fired is temporarily reduced or stopped when removing the deposits on the inner wall surface of the rotary kiln. . 3. The method for removing deposits on the inner wall surface of a rotary kiln according to claim 1, wherein the position of the firing burner is changed when removing the deposits on the inner wall surface of the rotary kiln.