JPH01242752A - Blowby detector for electric refinery furnace - Google Patents

Abstract

PURPOSE:To prevent the deterioration in the furnace conditions, damage of a burner, etc., by providing the temp. detector and sound detector to detect the temp. rise and abnormal sound due to blowby, etc., in an electric refinery furnace wherein combustion is carried out in the raw material by a burner. CONSTITUTION:The blowby detector consists of the temp. detector 10 for detecting the temp. above the insertion part of the burner 1 inserted into the raw material 3 in the electric refinery furnace 2, the sound detector 16 for detecting the sound made in the furnace 2, etc. The temp. detector 10 is provided with devices 11-15 for indicating the fact that the detected temp. becomes higher that the set value. In addition, the sound detector 16 is furnished with devices 17-22 for indicating the fact that the specified-frequency component among the detected sound signals becomes higher than the set value.

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention is applicable to, for example, an electric furnace for smelting ferronickel, etc., when the flame of a burner that burns the raw material in the furnace causes a phenomenon in which the raw material is vented. This atrium concerns a device for detecting phenomena.

[Conventional technology]

Conventionally, for example, in an electric furnace for smelting ferronickel, as shown in the figure, powdered raw material 3 preheated to 800 to 900 °C is charged into an electric furnace 2 from a raw material tube 4, and three electrodes 5 are charged. Electricity is applied, and the raw material 3 is heated and melted by Joule heat caused by a large current of the opposing ampere flowing between the electrodes 5 mainly through the slag layer 6. At this time, the ore in the raw material 3 and the reducing agent react and precipitate as a solution, forming a slag layer 6 and a metal layer 7 due to the difference in specific gravity. On the other hand, since the raw material 3 is choke-fed from the raw material tube 4, when it is melted and its volume decreases, it sequentially flows into the furnace. The slag and metal are then extracted at predetermined intervals.

By the way, in our country, since electrical energy is expensive, technology is being developed to use cheap fossil fuels to replace part of the electrical energy. The raw material in the electric furnace as a link 3
There is a method of inserting a burner IP into the high temperature part of the layer and burning heavy oil or pulverized coal with oxygen or oxygen-containing air at the tip of the burner 1 to promote dissolution of the raw material 3. In this method, as shown in the figure, multiple elongated burners L with a length of 5 to 6 m are used.
Each fuel is supported outside the furnace and inserted obliquely from above into the raw material 3 through a hole provided in the furnace lid 8, so that the fuel is combusted in the high temperature part of the raw material 3 above the slag layer 6. In this way, the raw material 3 is melted into a solution by the electric energy and high-temperature flame, and drops onto the slag layer 6 to be separated into metal and slag, with the metal settling into the metal layer 7.

On the other hand, the high-temperature gas generated at the tip of each burner 1 passes through the voids of the powdery raw material 3 and rises while preheating the raw material 3, and then passes from the entire surface of the raw material 3 to the furnace lid 8. It is discharged through the flue 9 and reused for drying ore and auxiliary raw materials, preheating, etc. However, if the path of the high temperature gas generated by the burner 1 is damaged, the gas will not rise uniformly within the layer of the raw material 3, but will concentrate in the - point, causing a phenomenon in the atrium, causing the solution and raw materials to spout out. This causes problems such as so-called shelf hanging, which worsens the furnace condition and reduces melting efficiency, and the flames cause local overheating of the furnace cover 8 and electrodes 5. In this case, it is necessary to pull out burner 1, adjust the angle, and change the insertion position, but since it is difficult to predict and detect this blow-through, workers must frequently inspect the inside of the furnace. ,
Not only is it time-consuming, but there are also problems such as a delay in discovery resulting in meltdown of the burner 1, a long time required to restore the furnace condition, and a reduction in the operating rate.

[Problem to be solved by the invention]

The purpose of the present invention is to solve the above-mentioned problems by inserting a burner into the high-temperature part of the raw material layer in an electric furnace to prevent local blow-outs that occur when burning heavy oil or pulverized coal with oxygen or oxygen-containing gas. The aim is to provide a device for detecting

[Means to solve the problem]

Means for solving the problems according to the present invention is an electric furnace in which fuel and oxygen-containing gas are supplied to a burner inserted into the furnace, and the burner is caused to burn in the raw material in the furnace. Equipped with a temperature detector installed to be able to detect the temperature inside the upper furnace, and a device that indicates when the temperature detected by the temperature detector exceeds a set value at predetermined intervals. The atrium has a detection device and a sound detector installed to detect the sound generated in the furnace of each insertion part of the burner, and a specific frequency signal of the acoustic signal detected by the sound detector is set to a set value. The detection device includes a device that indicates that the above has occurred.

[Effect]

The temperature inside the furnace can be detected using a normally used thermocouple, but since the temperature inside the furnace fluctuates widely, ranging from about 700 to 1)00C even during normal operation, it is not possible to determine whether or not there is a blow-through just by detecting the maximum temperature. Therefore, when the temperature rise at a predetermined time interval of 2 to 15 minutes or every hour exceeds a predetermined value, this is indicated by flashing a lamp, a buzzer, etc.
Workers inspect the inside of the furnace to confirm whether the atrium is in good condition and take appropriate action. This is because, unlike a general temperature rise, in the case of blow-through, the temperature rises in a short time due to the high-temperature gas blowing through. It is desirable to install a temperature sensor for each burner.

Inside the furnace, there are usually arcing noises emitted by the electrodes, and before the raw material descends, etc.
Various noises are generated, but when the burner flame blows through the atrium, a unique sound is added to the atrium.

Therefore, if the sound of this frequency is separated, and the volume reaches a set value or higher, an alarm is issued, and a worker can confirm this in the same way as when detecting temperature. As this sound detector, it is necessary to use a microphone and provide it for each burner. For these atriums, it is more desirable to use both detection devices in combination, as this allows for reliable detection of abnormalities and prompt countermeasures.

(Example〕 An embodiment of the present invention will be described with reference to the drawings.

As a detector for the temperature inside the electric furnace 2, two thermocouples 10 are installed above the tip of the burner 1 inserted into the raw material 3.
．． 10 is inserted through the furnace lid 8, and this temperature signal is displayed and recorded on the temperature recorder 12 via the AD converter 1). At the same time, the temperature signal is converted into a digital signal by the AD converter 1) and sent to the computer. Enter 13. The time (2 minutes) is displayed in the calculator 13.
and temperature (20'c) are set on the setting device 14, and a temperature signal is input every 2 minutes of the set time, and if the temperature rise exceeds 20 tZ' in 2 minutes, the alarm 15 is activated. .

Further, if necessary, the burner may be automatically pulled up in conjunction with the drive device for the burner 1.

Next, as a sound detector in the atrium, a heat-insulated sound-collecting microphone 16 facing into the furnace is arranged near the insertion opening of the burner 1 made in the furnace lid 8. After this acoustic signal is amplified by an amplifier 17, only frequencies of 5 to 10 KHz are extracted by a band-pass filter 18, demodulated by a demodulation circuit 19, and displayed on a monitor 20, as well as input to a discrimination circuit 21. Compared to the volume during normal operation, if there is a difference of, for example, 10 dB or more, the alarm 22 is activated. Further, if necessary, the burner 1 may be automatically pulled up in conjunction with the burner 1 drive device.

Equipment other than the temperature detector 10 and sound detector 16 mentioned above are installed in the operation room (not shown) of the electric furnace, so they are monitored along with other instruments during operation, and if an abnormal value is discovered or an alarm is activated. Then, the worker inspects the inside of the furnace to confirm whether there are any abnormalities, and if blow-by occurs, take measures such as reinserting the burner. These temperature rise values, increased sound volume, selected frequency range, etc. ,
It may be selected as appropriate depending on the characteristics of the furnace.

(Effects of the Invention) As explained above, according to the present invention, it is possible to respond appropriately when blow-by occurs.As a result, deterioration of furnace conditions and damage to burners due to continued blow-by can be prevented. ,
It is possible to improve the operation rate and melting efficiency of the electric furnace.

[Brief explanation of the drawing]

The figure is an explanatory diagram of the device of the present invention. 1. Burner 2. Electric furnace 3. Raw material 4. Source tube 5. Electrode 6. Slag layer 7. Metal layer 8
... Furnace lid 9 ... Flue 10 ... Thermocouple 1) ... AD converter 12 ... Recorder 13 ... Calculator 14 ... Setting device 15
・・Alarm 16・・Microphone 17・・Amplifier 18
... Bandpass filter 19 ... Demodulation circuit 20 ...
Monitor 21...Discrimination circuit 22...Alarm device

Claims (2)

[Claims] (1) In an electric furnace that supplies fuel and oxygen-containing gas to a burner inserted into the furnace and causes the burner to burn in the raw material inside the furnace, it is possible to detect the temperature inside the furnace above the insertion part of the burner. An atrium of an electric furnace for smelting, which is equipped with a temperature detector installed at the temperature detector, and a device that indicates when the temperature detected by the temperature detector increases at predetermined intervals beyond a set value. Detection device. (2) In an electric furnace that supplies fuel and oxygen-containing gas to burners inserted into the furnace and causes the burners to burn in the raw material inside the furnace, the noise generated in the furnace at each insertion part of the burner is An electric furnace for smelting, comprising a sound detector installed to enable detection, and a device that indicates when a specific frequency component of the acoustic signal detected by the sound detector exceeds a set value. Atrium detection device.