JPH11294971A - Method for detecting water leakage of watercool structure in metal melting/refining furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically detect water leakage from a watercooling structure with a metal melting/refining furnace at an early stage. SOLUTION: In a metal melting/refining furnace 1 where a watercooling structure 1W is provided at least at one part of the furnace wall, furnace lid, or the like of an furnace, when water leakage from the watercooling structure 1W is detected, a water detection sensor 5 is provided near the watercooling structure 1W, and the concentration of steam in an atmosphere gas is measured, thus detecting the water leakage from the watercooling structure 1W.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water cooling structure such as a metal melting furnace or a metal refining furnace, in which a water cooling structure such as a water cooling panel is provided on a part of the furnace such as a furnace wall or a furnace lid. The present invention relates to a method for detecting a water leak of a water-cooled structure in a metal melting and refining furnace suitable for detecting a water leak from a furnace at an early stage and also automatically.

[0002]

2. Description of the Related Art For example, in the case of producing steel from scrap as a raw material, an electric arc type metal melting furnace is used, and raw materials such as scrap, dalai powder, and pig iron are charged into the metal melting furnace. It is common to melt by arc heating (for example, "Third Edition Iron and Steel Handbook, Volume II, Ironmaking and Steelmaking", published October 15, 1979, p. 527-
Page 562, "10. 1 Arc furnace").

[0003] In this kind of electric arc type metal melting furnace, it is general that almost all of the furnace body and furnace lid are constructed of refractory bricks. However, in order to reduce the cost of refractories thereafter, In addition, a water-cooled structure such as a water-cooled panel (or a water-cooled box) is used instead of part or most of the refractory brick in the furnace wall and the furnace lid.

[0004]

However, if water leaks from a water-cooled structure and water adheres to a refractory brick such as magnesia for a long time, the refractory brick deteriorates due to alteration or volume expansion. For this reason, there is a problem that it cannot be said that erosion does not proceed and hot water leakage does not occur.

Although a water leak can be detected based on a difference between the amount of water supplied to the water-cooled structure and the amount of drainage from the water-cooled structure, it is difficult to detect a small amount of water at an early stage. was there.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems, and is directed to a metal having a water-cooled structure such as a water-cooled panel on a part of a furnace such as a furnace wall or a furnace lid. It is an object of the present invention to enable early and automatic detection of water leakage from a water-cooled structure in a melting and refining furnace.

[0007]

According to a first aspect of the present invention, there is provided a method for detecting water leakage of a water-cooled structure in a metal melting and refining furnace. When detecting water leakage from the water-cooled structure in a metal melting and refining furnace equipped with a water-cooled structure in part, by providing a moisture detection sensor near the water-cooled structure, by measuring the concentration of water vapor in the atmosphere gas It is characterized in that water leakage from a water-cooled structure is detected.

According to an embodiment of the present invention, in the method for detecting water leakage of a water-cooled structure in a metal melting and refining furnace, the moisture detection sensor is formed by decomposition of water vapor. It is possible to use an oxygen ion conductive solid electrolyte for measuring the water vapor concentration with the oxygen.

Similarly, in an embodiment of the method for detecting water leakage of a water-cooled structure in a metal melting and refining furnace according to the present invention, the concentration of water vapor in the atmospheric gas is equal to or higher than a predetermined value. It can be determined that a water leak has occurred when the state is continued for a predetermined time or more. More specifically, as described in claim 4, the water vapor concentration in the atmosphere gas is When the state of 20% or more continues for 1 minute or more, it can be determined that water leakage has occurred.

[0010]

1 to 3 show one embodiment of a method for detecting water leakage of a water-cooled structure in a metal melting and refining furnace according to the present invention. The metal melting and refining furnace 1 is an electric arc furnace. Shows the case.

That is, the metal melting and refining furnace (electric arc furnace) 1 has a furnace bottom portion formed of a fixed refractory brick 1B and an irregular refractory brick 1C, and a large portion of the furnace wall is a water-cooled structure. The water cooling panel 1W and the furnace shell 1S are formed by a certain water cooling panel 1W and the furnace wall 1S. The burner 2 is provided to penetrate the water cooling panel 1W and the furnace shell 1S. 4, the structure is such that the arc is heated and, if necessary, the flame is heated by the burner 2.

The burner 2 has a water-cooling sleeve 2S at a portion penetrating the water-cooling panel 1W and the furnace shell 1S, and has a vicinity of the water-cooling structure 1W, that is, a lower portion of the water-cooling panel (1W) and a fixed-form refractory brick. The upper part of 1B is provided with a moisture detection sensor 5, and the output from the moisture detection sensor 5 is to be processed by a computing unit 6.

As shown in FIG. 2, the moisture detecting sensor 5 is made of platinum (Pt) at both ends of an oxygen ion conductive solid electrolyte 5S such as calcia (CaO) stabilized zirconia (ZrO ₂ ). Electrodes E ₁ and E ₂
And a power supply E for the sensor between the electrodes E ₁ and E _2.
With _S is is connected, at its opposite ends provided with a heater 5H power E _H for heater are connected.

[0014] The moisture detection sensor 5, the oxygen ion conductive solid electrolyte 5S is heated to about several hundred ℃ by the power supply E _H and the heater 5H heater oxygen ions (O
^2- ) Conduction becomes possible.

[0015] Therefore, when gradually increasing the voltage applied by the power source E _S sensors, as shown in FIG. 3, the first limiting current is proportional to the ambient oxygen concentration current i does not increase i ₁
Appears, and when the applied voltage is further increased, when the atmosphere contains a large amount of moisture due to water leakage from the water-cooled panel 1W, the second limit current i ₂ proportional to the water vapor concentration is increased.
Appears.

[0016] This water leaked from the water cooled panels 1W (molecule) is because the electrolyzed with oxygen ions (O ^2-) generated, the first limit current i ₁ is proportional to the partial pressure of oxygen in the atmosphere Since the second limit current i ₂ is proportional to the partial pressure of water vapor in the atmosphere, the oxygen concentration and the water vapor concentration can be measured by detecting these currents i ₁ and i ₂ .

During normal operation (water vapor concentration is 4%
That the water leakage from the water-cooled panel 1W can be detected by detecting that the water vapor concentration has increased (for example, increased to 10% or more) by the moisture detection sensor 5 and the computing unit 6 as compared with before and after). Become.

Therefore, as compared with a case where a water leak is detected based on a difference between a supply amount of the cooling water to the water cooling panel 1W and a discharge amount of the cooling water from the water cooling panel 1W, the water leakage stage is started at a very small water leakage stage. It is possible to detect the occurrence of water leakage.

According to one embodiment, the moisture amount measured by the moisture detection sensor 5 during normal times is 4%, but when the operation is repeated several times, the moisture amount becomes 10%.
%, The water-cooled panel 1W was examined. As a result, it was confirmed that a small amount of water leakage occurred. By closing the cooling water supply valve to the water-cooled panel 1W, a large amount of water leakage was detected. It was possible to stop.
Therefore, it is possible to prevent cracks or breakage from occurring due to volume expansion due to water penetration into the refractory, and normal operation can be resumed within a short time by early replacement of the water cooling panel 1W. Met.

In the above-described embodiment, the water cooling panel 1W constituting the side wall of the furnace body is shown as an example of the water cooling structure. However, the water cooling structure is limited to only the water cooling structure such as the water cooling panel 1W of the furnace wall. It goes without saying that it will not be done.

[0021]

According to the method for detecting water leakage of a water-cooled structure in a metal melting and refining furnace according to the present invention, a water-cooled structure is provided on a part of a furnace such as a furnace wall or a furnace lid. When detecting water leakage from the water-cooled structure in a provided metal melting and refining furnace, a water detection sensor is provided in the vicinity of the water-cooled structure, and water from the water-cooled structure is measured by measuring the water vapor concentration in the atmosphere gas. Since the leak is detected, it can be detected at the initial stage when the water leak from the water-cooled structure is extremely small, and it is possible to prevent the adverse effect on the refractory material beforehand There is a great effect that there is.

And, as described in claim 2,
The moisture detection sensor uses an oxygen ion conductive solid electrolyte that measures the concentration of water vapor using oxygen generated by the decomposition of water vapor. A remarkable effect is obtained that it is possible to detect water leakage from an object at an early stage.

As described in claim 3, when the state in which the water vapor concentration in the atmospheric gas is equal to or higher than a predetermined value continues for a predetermined time or longer, it is determined that water leakage has occurred. According to a fourth aspect of the present invention, it is determined that a water leak has occurred when a state in which the concentration of water vapor in the atmospheric gas is 20% or more continues for 1 minute or more. A remarkable effect that it is possible to more reliably detect water leakage from an object is provided.

[Brief description of the drawings]

FIG. 1 is a partial explanatory view of a metal melting and refining furnace showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the structural principle of a moisture detection sensor.

FIG. 3 is an explanatory diagram illustrating a characteristic principle of a moisture detection sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal melting and refining furnace 1B Fixed refractory brick 1C Irregular refractory brick 1S Furnace 1W Water-cooled structure (water-cooled panel) 2 Burner 2S Water-cooled sleeve 3 Furnace interior material 4 Electrode 5 Moisture detection sensor 6 Computing unit

Claims (4)

[Claims] When detecting water leakage from a water-cooled structure in a metal melting and smelting furnace provided with a water-cooled structure in a part of a furnace such as a furnace wall or a furnace lid, a moisture detection sensor is provided near the water-cooled structure. A method for detecting water leakage from a water-cooled structure in a metal melting and refining furnace, by detecting a water vapor concentration in an atmospheric gas. 2. The metal melting and refining device according to claim 1, wherein the moisture detection sensor uses an oxygen ion conductive solid electrolyte for measuring a water vapor concentration by using oxygen generated by decomposition of water vapor. A method for detecting water leakage from a water-cooled structure in a furnace. 3. The method according to claim 1, wherein it is determined that water leakage has occurred when the state in which the water vapor concentration in the atmospheric gas is equal to or higher than a predetermined value continues for a predetermined time or longer. A method for detecting water leakage from a water-cooled structure in a smelting furnace. 4. The metal melting and refining furnace according to claim 3, wherein it is determined that water leakage has occurred when the state in which the water vapor concentration in the atmospheric gas is 20% or more continues for 1 minute or more. For detecting water leaks from water-cooled structures in Japan.