JPH042733A - Method for detecting and controlling abnormal falling of material in vertical melting furnace - Google Patents

Abstract

PURPOSE:To easily detect the abnormal falling of a material and to stably operate a vertical melting furnace by detecting the clogging of a melt outlet of the furnace with the unmelted material from the lowering of the temp. of the melt at the outlet or its atmosphere pressure. CONSTITUTION:The raw material 14 is charged into the main body 20 of a vertical melting furnace 12 from its inlet 16 and melted by a burning means 24 consisting of burner groups 22A, 22B and 22C, and the melt W is discharged from an outlet 18. In this case, a controller 10 provided with a radiation thermometer 32 for detecting the temp. of the melt W discharged from the outlet 18 or a pressure gage 34 for detecting the atmosphere pressure at the outlet 18 is provided. When the unmelted material falls in the main body 20 to clog the outlet 18 and the melt W is retained in the furnace, the abnormality is detected by the control means 30 from the lowering of the temp. of the melt from the outlet 18 or atmosphere pressure at the outlet 10, and the output of the burner groups 22A-22C is increased. Consequently, the furnace 12 is stably operated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a vertical melting furnace in which raw materials such as metal lumps are melted and flowed out, and unmelted raw materials fall down and block the outlet of the furnace. The present invention relates to a method for detecting an abnormality in which melted material stagnates at an outlet, and controlling the combustion state in the furnace based on the detection of this stagnation abnormality to eliminate the abnormality in the furnace.

(Prior Art) A vertical melting furnace consists of a furnace body having an inlet into which raw materials such as metal lumps are input and an outlet through which melted material flows out, and a plurality of stages of combustion burners installed within the furnace body. The raw material flows out from the outlet while being melted by these multiple stages of combustion burners. The melt flowing out of the outlet of the furnace body is accumulated in a melt holding furnace through an inclined melt passage, and is led from this holding furnace to a suitable processing means.

On the other hand, in a vertical melting furnace, unmelted raw materials may fall from the furnace wall and block the outlet of the furnace, resulting in an abnormality in which the melt does not flow out of the outlet and stagnates.

In conventional technology, the outflow port is blocked by falling undissolved raw materials, and an abnormality in which melted material stagnates at the outflow port is detected by a worker directly monitoring the outflow port and detecting that the outflow port is blocked. When this happened, the output of the combustion burner near the outlet was increased to melt the unmelted raw material that had fallen.

[Problem that the invention seeks to solve]

However, in this conventional technology, in order to detect falling unmelted raw materials in the melting furnace, a worker must constantly monitor the outlet of the melting furnace, resulting in low workability. There was a drawback that the melting furnace could not be operated stably because there was a risk of overlooking abnormalities.

In order to avoid the above-mentioned drawbacks, the first object of the present invention is to provide a vertical melting method that automatically detects the blockage of the outlet due to falling undissolved raw materials and the abnormality of stagnation of the melt caused by this blockage. An object of the present invention is to provide a method for detecting abnormality in material falling in a furnace.

In order to avoid the above-mentioned drawbacks, the second object of the present invention is to detect an abnormality in the blockage of the outlet due to falling undissolved raw materials and stagnation of the melt due to this blockage, and to adjust the combustion state so as to eliminate this abnormality. An object of the present invention is to provide a method for controlling a vertical melting furnace, which enables stable operation of the melting furnace.

[Means to solve the problem]

In order to solve the first problem, the present invention solves an abnormality in which unmelted materials in a vertical melting furnace where raw materials are melted and flowed out fall and block the outlet, and the melt stagnates at the outlet. The present invention provides a method for detecting material fall abnormality in a vertical melting furnace by detecting a drop in the temperature of the melted material at the outlet or the atmospheric pressure at the outlet.

In order to solve the second problem, the present invention also provides a vertical melting furnace in which raw materials are melted and discharged, and has a means for controlling the combustion state of the raw material, and the unmelted material in the vertical melting furnace is An abnormality in which melted material falls and blocks the outlet and stagnates at the outlet is detected from the temperature of the melted material at the outlet or a decrease in the atmospheric pressure at the outlet. A method for controlling a vertical melting furnace used to control combustion conditions is provided.

[Effect]

If an abnormality occurs in the falling of unmelted raw materials in a vertical melting furnace and the furnace outlet is blocked and the melt does not flow out and stagnates at the outlet, the temperature of the melt coming out of the outlet will be lower than that of the unmelted raw materials. Heat is taken away and the temperature decreases. Furthermore, if the outlet is blocked by falling undissolved raw materials, the amount of combustion gas in the furnace blown out from the outlet decreases, and the atmospheric pressure at the outlet decreases.

Therefore, if a decrease in the temperature or atmospheric pressure of the melted material at the outlet is observed, it is possible to detect an abnormality caused by falling undissolved raw materials.

In addition, the melting furnace has a means for controlling its combustion state, and when the combustion state is controlled in response to the detection of an abnormality in the falling of unmelted raw materials, the unmelted raw materials are melted and the outlet is automatically blocked. Once removed, the melting furnace can be operated stably.

(Example) The example of the present invention will be described in detail with reference to the drawings.
The figure shows a vertical melting furnace control device l used to implement the method for detecting material fall abnormality and controlling method for a vertical melting furnace according to the present invention.
A vertical melting furnace 12 is used to store raw materials 14 such as metal ingots.
An inlet 16 through which the melt is input and an outlet 18 through which the melt flows out.
A furnace body 20 having a furnace body 20, and a combustion burner group 22A of multiple stages, in the illustrated embodiment, three stages, installed in the furnace body 20.
, 22B, and 22C. Combustion burners 22A, 22B, 22C at each stage are supplied with motor-driven valves 26A, 26B, 26 from a fuel supply source (not shown).
Fuel at a predetermined pressure is supplied via C, and each motor-driven valve 2
6A, 26B, 26C are motors 28A, 28B, 28C
respectively driven by

A motor-driven valve 26 for controlling the combustion state of the melting furnace 12
A control means 30 is provided for supplying control signals Sa, Sb, and Sc to motors 28A, 28B, and 28C of A, 26B, and 26C, respectively, and this control means 30 is composed of a CPU such as a computer. This CPU also detects an abnormality in material falling and generates a control signal Sco for controlling the control means 30, as will be described later.

The raw material 14 is not melted in the furnace body 20 by the combustion barge groups 22A, 22B, and 22C in multiple stages, and then flows out from the outlet 18.

The melt that has flown out from the outlet 18 of the furnace body 20 in this way passes through the melt passage and is accumulated in a melt holding furnace (not shown), and is guided from this holding furnace to an appropriate processing means.

The control device 3110 further includes a radiation thermometer 32 for detecting the temperature of the melt W flowing out from the outlet 18 or a pressure gauge 34 for detecting the atmospheric pressure at the outlet 18 .

In the method of the present invention, unmelted material in the furnace body 20 of the melting furnace 12 falls and blocks the outlet 18, and the melted material is removed from the outlet 18.
An abnormality in which the melt does not flow out from the furnace and stagnates in the furnace is detected by the control means 30 from a decrease in the temperature of the melt flowing out from the outlet 18 or a decrease in the atmospheric pressure at the outlet.

An abnormality occurs in which unmelted raw materials fall in the melting furnace 12, and the outlet 18 of the furnace is blocked, and the melt does not flow out, resulting in the outlet 1
8 and stagnates, the temperature of the melt 1 coming out of the outlet 18 decreases as heat is taken away by the undissolved raw materials. In addition, the outlet 1
8 or the outlet 18 is blocked by falling undissolved raw materials, the combustion gas injected from the lowest combustion burner 22C or the outlet 18
The amount of air blown out from the outlet 18 decreases, and the atmospheric pressure at the outlet 18 decreases. Therefore, as described above, if a decrease in the temperature or atmospheric pressure of the melt coming out of the outlet 18 is observed, it is possible to detect an abnormality due to falling undissolved raw material.

The control means 30 also controls the detection signal of the material fall abnormality to reflect the combustion state of the melting furnace 12, especially the lowest combustion burner C.
It is used to control the output to increase.

Next, a specific example of the present invention for detecting a material fall abnormality from the temperature drop of the melt at the outlet of the melting furnace will be described with reference to FIG. 2.The raw material to be melted is copper, and the melting furnace is approximately 20t
/ hour, and the combustion burners of the combustion means are operated as 7 burners, 7 burners, and 6 burners in order from the top at a combustion pressure of 10 to 30 inches of water column, and the outlet (tap hole) of the melting furnace is operated at a combustion pressure of 10 to 30 inches of water column. The melt temperature (hereinafter referred to as outlet temperature) was measured using a radiation thermometer. The outlet temperature TO under normal conditions without any abnormality of material falling was about 1450 to 1500°C (see Figures 3(A) and 3(B)).

During operation of the furnace, the control means 30 is in operation, and the flow indicated by the vertical line in the center of the flowchart of FIG.
This is done every minute (see abnormality response in the flowchart).

It is determined whether the outlet temperature To has become 1450°C or less, and if it has become 1450°C or less, it has decreased by 50°C or more from the outlet temperature T15 at the time of 15 minutes past, and To≦T+550. (Equation 1), or the outlet temperature T2 decreases by 20°C or more from the point in time 2 minutes past.
It is determined whether ≦T220 (equation 2).

If neither (Equation 1) or (Equation 2) holds true, it is assumed that there is no abnormality, and the control stage f waits for the next measurement one minute later. In addition, if the above (1 formula) and (2 formula)
If either of the above is true, the outlet is blocked due to falling undissolved raw material, and an abnormality in material falling is detected.

When this abnormality is detected, the control means 30 uses the falling material detection signal as a control signal Sco to control the lowermost combustion burner group 22.
The combustion pressure Pc of the lowest combustion burner group 22C becomes the highest value in the control range, that is, 30 inches of water column, and the other combustion burners 22A, 22
The combustion pressure Pa and Pb of B are controlled to be 10 inches of water column. This combustion pressure is maintained until the outlet temperature To rises by 20°C or more. In this way, when the outlet temperature To returns to normal, the outlet temperature T is increased every minute in the same way as above.

monitor and detect any abnormalities.

The flow on the right side of the flowchart in FIG. 2 shows the flow for recovery after an abnormality has occurred, and TA in the figure indicates the outlet temperature at the time when the abnormality occurred.

3(A) and 3(B) respectively show changes in the outlet temperature (taphole temperature) of a melting furnace as a specific example of the present invention, and FIG. 3(A) shows the case where the above (Equation 1) holds true. In addition, FIG. 2B shows a case where the above (2 formulas) hold true.

In addition, although the above specific example shows a case where an abnormality in material falling is detected by measuring the temperature at the outlet, it is also possible to detect an abnormality in material falling by measuring the atmospheric pressure near the outlet.
For example, a heat-resistant pipe is inserted into the outlet, and the atmospheric pressure AP is detected by a pressure gauge through the heat-resistant pipe. Under normal conditions, this pressure AP is about 12-20 mm water column.

As shown in FIG. 4, when this pressure AP becomes less than 10 mm of water column, it is immediately detected that there is an abnormality in material falling. In this case, the lowest combustion burner group 22C
The combustion state is controlled by the control means 30 so that the combustion pressure PC becomes 30 inches of water column, and the combustion pressures Pa and Pb of the other combustion burner groups 22A and 22B become 10 inches of water column.This state is shown in FIG. As shown, the atmospheric pressure AP
Hold until the water column rises above 13mm. In FIG. 4, tl indicates the time point at which the abnormality occurs, t2 indicates the time point at which the abnormality is released and returns, and 1p indicates the time during which material clogging occurs.

In addition, in the above specific example, an abnormality is detected when the decrease in the outlet temperature continues for a predetermined period of time or more, and this is distinguished from the case where the decrease in the outlet temperature occurs temporarily even under normal conditions. (Effects of the Invention) According to the present invention, as described above, when an abnormality occurs in which unmelted raw materials fall in the vertical melting furnace and block the outlet and the melt stagnates, the outlet temperature decreases. It is possible to easily detect abnormalities in material falling by measuring these temperatures or pressures by taking advantage of phenomena such as a decrease in temperature or atmospheric pressure at the outlet. Since the combustion state of the furnace is controlled according to the detection, blockages in the outlet due to falling materials are automatically removed, allowing stable operation of the melting furnace.

[Brief explanation of drawings]

FIG. 1 is a system diagram of an example of a melting furnace using a melting furnace control device used to carry out the method according to the present invention, FIG. 2 is a flowchart explaining the present invention in detail, and FIG. 3 (A)
(B) is a diagram showing different states of change in outlet temperature in a specific example of the present invention, and FIG. 4 is a diagram showing different states of change in atmospheric pressure in a specific example of the present invention. 10---1 vertical melting furnace control device, 12-111 melting furnace, 14---1 raw material, 16---input port,
18----First outlet, 20-1111 Furnace body, 22A
, 22B, 22C-11--Combustion harness group, 24--1-Combustion means, 26A, 26B, 26C--Motor driven valve, 30---1 Control means, 32-- - radiation thermometer, 34 - - pressure gauge. Patent applicant Agent Patent attorney Arata Kikuchi - 2nd WJ Figure [A1 10 minutes ago 5 minutes 2 minutes ago current time 1 minute] 閤H30 Figure 4

Claims (2)

[Claims] (1) An abnormality in which unmelted material in the vertical melting furnace that melts and flows out raw materials falls and blocks the outlet, causing the melt to stagnate at the outlet or the temperature of the melt at the outlet or the outlet. A method for detecting abnormality in material falling in a vertical melting furnace by detecting a drop in atmospheric pressure. (2) The vertical melting furnace that melts and flows out the raw materials has a means for controlling its combustion state, and the unmelted material in the vertical melting furnace falls and blocks the outlet, causing the melt to flow out. An abnormality in which the melt stagnates at the outlet is detected from a decrease in temperature of the melt at the outlet or atmospheric pressure at the outlet, and a detection signal of the abnormality in which the melt stagnates at the outlet is used to control the combustion state. Control method for vertical melting furnace.