JPS61268915A - Slag port control device for waste material melting and processing furnace - Google Patents

Abstract

PURPOSE:To enable an automatic operation of a waste material melting and processing furnace to be performed and to sense a continuous flowing-out of molten slag by a method wherein a temperature sensor is arranged near a slag port for the molten slag so as to detect the temperature of the molten slag in its floating condition. CONSTITUTION:A temperature sensor 30 is arranged at a location where the molten slag 8 dropped from a sensing window 31 formed at a part lower than a slag port 13 for the molten slag 8 can be confirmed. Therefore, when the molten slag 8 is discharged from the slag port 13 through a discharging passage 9, the temperature of the molten slag 8 to be dropped is detected by the temperature sensor 30 through the sensing window 31. With this arrangement, the temperature of the molten slag is judged and it is judged that the molten slag is flowing out through the slag port when the molten slag shows a temperature whereby its flowability is generated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a waste melting processing furnace, and in particular, when the molten slab or molten steel discharged from the waste slag outlet is interrupted, it can be restarted again. This invention relates to a slag outlet control device for a waste melting processing furnace that controls the slag to be discharged.

[Prior art] Wastes such as sewage sludge, sludge incineration residue, municipal garbage incineration residue, treatment products of wastewater discharged from mines and factories, other industrial wastes and their incineration, which are generally treated in treatment furnaces. Ash contains heavy metals that are harmful to humans and living things, such as chromium, nickel, manganese, cadmium, mercury, and copper, and national regulations are in place for the disposal of such waste.

Conventionally, waste containing these heavy metals has been disposed of by landfilling, etc., but it has become increasingly difficult to secure land for landfilling, and over the years, heavy metals have been leached into the ground.
This has not necessarily been an adequate treatment method, as there is a risk of contaminating the area around the landfill.

Therefore, in recent years, methods of melting and solidifying these wastes have been proposed. One of the methods is solidification using an electric arc furnace. This method uses an electric arc furnace based on a steelmaking arc furnace equipped with graphite electrodes to
Base metal in a high temperature molten state of about 50 ["C],
For example, a metal hot water made of iron is made, the above-mentioned waste is added thereto, the heavy metals contained therein are melted and captured in the base metal, and the inorganic components are converted into molten slag containing some of the above-mentioned heavy metals. The generated gas is separated by floating on top, taken out of the furnace, cooled, and collected.

Since this method uses high-temperature arc heat, the waste is completely melted and slag with a uniform structure is obtained.Since it uses a base metal, heavy metals are captured and converted into slag. Can be separated. Since the amount of gas generated is smaller than when a combustion furnace is used, the exhaust gas treatment equipment can be compact, and there are advantages such as good thermal efficiency because heat loss due to exhaust gas is small.

On the other hand, however, in such a melting furnace, as waste is continuously input and processed, molten slag generated and suspended on the base metal gradually accumulates, reducing the processing capacity. The slag must be discharged outside the furnace, but the melting point of slag is extremely high and it may cool and solidify near the discharge section of the furnace body, closing the discharge passage, which poses the problem of preventing smooth discharge. be.

Therefore, the present applicant filed an application regarding a waste melting processing furnace shown in FIGS. 4 and 5.

Hereinafter, an explanation will be given based on drawings showing a conventional example of the waste melting processing furnace.

Figure 4 is a sectional view showing the configuration of a conventional waste melting processing furnace;
FIG. 5 is an enlarged cross-sectional view of the main parts of the discharge section.

In the figure, ``la'' is a furnace body consisting of a base 2 made of a refractory material and a reinforced outer shell 3 surrounding the base 2, and the inside of which is filled with a base metal 7 such as iron. 1b is a molten slag 8 integrally formed in the furnace main body 1a.
This is the discharge section. Further, 4 is a passage for introducing waste into the furnace main body 1a, 5 is a main electrode for heating, and 6 is a recovery conduit for combustible gas generated during the melting process. The furnace body 1a is provided with a discharge passage 9 for discharging the molten slag 8 floating on the base metal 7, and a discharge cover 10 integrally attached to the furnace body 1a and the discharge part 1b is provided with a discharge passage 9 from the discharge passage 9. Auxiliary electrodes 16 and 17, which have the function of generating arc heat and Joule heat to prevent the discharged molten slag 8 from solidifying in the discharge passage 9, are vertically movable up and down (indicated by arrows). By adjusting the power supplied to the auxiliary electrodes 16 and 17, the amount of arc heat and Joule heat generated is adjusted, and the fluidity of the molten slag 8 is maintained.

When the molten slag 8 is being discharged smoothly, the auxiliary electrode 1
6 and 17 are pulled up to the outside of the molten slag 8, and when there is a possibility that the fluidity of the molten slag 8 decreases and solidifies, making it difficult to discharge, they are lowered into the molten slag 8 that is being discharged, and the The fluidity of the molten slag 8 is increased by introducing it into the molten slag 8 and using arc heat, Joule heat, etc.

When starting when the molten slag 8 has solidified in the discharge passage 9 due to a power outage, the auxiliary electrodes 16 and 17 are lowered to bring their tips into contact with the surface of the molten slag 8, and the slag is melted by arc heat. Promote. The materials used for the auxiliary electrodes 16 and 17 include molybdenum electrodes, graphite, iron, and tungsten electrodes. Ejection cover 10
In addition to the above-mentioned auxiliary electrodes 16 and 17, auxiliary electrode 1
A conductive material supplying device 18 for supplying IJ conductive material forming a mechanism for generating arc heat, Joule heat, etc. in 6 and 17.
, and a discharge duct 19 for the gas generated from the molten slag 8 being discharged. As the conductive material, for example,
Graphite, iron particles, a crushed mixture of both, etc. are used. The conductive material is used, for example, when restarting the operation of the melting furnace after it has been interrupted due to a power outage, construction failure, etc., when the molten slag 8 solidifies in the discharge passage 9 and electricity cannot be supplied. When this is added, electricity can be applied through the conductive material, which enables early start of operation, and is not particularly necessary when the discharge is in good condition.

The side discharge cover 10a is provided with an auxiliary electrode 20 that appears and retracts in a direction (indicated by an arrow) parallel to the direction in which the molten slag 8 comes out in the discharge passage 9. The auxiliary electrode 20
is made of the same material as the auxiliary electrodes 16 and 17, and similarly has the function of preventing the molten slag 8 from solidifying in the discharge passage 9 and melting and fluidizing the solidified molten slag 8 during startup. That is, in this type of waste melting processing furnace, the auxiliary electrodes 16 and 17 that move vertically up and down and the auxiliary electrode 20 that moves horizontally are located in the discharge passage 9 of the molten slag 8, as described above, and the auxiliary electrode 20 is moved horizontally. Preventing solidification in the thickness direction, melting and fluidizing the solidified molten slag 8 at the time of restarting operation, and exerting the same effect in the slag direction at the same time, allowing smooth discharge of the molten slag 8 and quickly returning to the current state at the time of restarting the operation. It measures the In addition to the auxiliary electrode 20, the side discharge cover 10a is provided with a viewing window 21 for monitoring the discharge state of the molten slag 8.

As described above, the molten slag 8 discharged passes through the discharge passage 9 and the slag outlet 13, and due to the weight of the molten slag 8,
It is put into a bit 15 filled with water 14 and is rapidly cooled.
It is finely divided into particles that can be easily handled later.

[Problem 1 to be solved by the invention However, the auxiliary electrodes 16 and 1 of the waste melting processing furnace
7 and 20, a person visually judges the solidification state of the molten slag 8 in the vicinity of the slag outlet 13 through the viewing window 21,
It was necessary to control the processing furnace, and it was not possible to automate it.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to indirectly detect the state of molten slag near the slag outlet and to detect the continuous outflow state of molten slag in order to enable automation of a waste melting processing furnace.

[Means for Solving the Problems] The waste melting furnace according to the present invention includes a temperature sensor, for example, a radial temperature sensor, for detecting the temperature of the molten slag, near the slag outlet for the molten slag. A temperature sensor such as a radiation thermometer is installed to detect the temperature of the molten slag in a flowing state.

[Operation] In the present invention, the temperature of the molten slag is determined by a temperature sensor disposed near the slag outlet of the molten slag flowing out from the slag outlet of the waste melting processing furnace, and the temperature of the molten slag in a flowing state is determined. It is determined that the molten slag is flowing out from the slag outlet when the temperature is such that it has fluidity.

[Example] Next, examples of the present invention will be described.

FIG. 1 is a sectional view of a main part of a discharge section of a waste melting furnace according to an embodiment of the present invention. In addition, other than the differences listed below,
The furnace main body 1a is the same as the conventional waste melting furnace shown in FIGS. 3 and 4, and the discharge section 1b is basically the same.

Next, the differences between the waste melting processing furnace of this embodiment shown in FIG. 1 and the conventional waste melting processing furnace shown in FIGS. 4 and 5 will be explained.

The end of the reinforcing shell 3 on the slag outlet 13 side is formed so that the molten slag 8 flows out of the discharge passage 9 as quickly as possible. Further, the side discharge cover 10a is attached to a position below the slag outlet 13, and a detection window 31 is provided in a portion below the slag outlet 13. The detection window 3
A temperature sensor 30 is disposed at a position where the molten slag 8 falling from the molten slag 8 can be confirmed. That is, the molten slag 8 and the detection window 31
and the temperature sensor 30 are arranged in a straight line. The temperature sensor 30 preferably has a radiation fJ4, such as a radial temperature sensor.
A device that detects temperature by radiation is preferable.

Therefore, when the molten slag 8 is discharged from the slag outlet 13 via the discharge passage 9, the temperature of the falling molten slag 8 is detected by the temperature sensor 3o through the detection window 31. When the molten slag 8 has fluidity, usually approximately 1
It is in the range of 400 to 1600 ['C]. When the fluidity of the molten slag 8 decreases and solidifies, the falling of the molten slag 8 is interrupted, and the temperature sensor 30 detects the molten slag 8.
The temperature of the reinforcing shell 3 or the atmosphere of the slag outlet 13 is detected instead of directly detecting the temperature, and the temperature detected by the temperature sensor 30 suddenly drops.

Furthermore, when the molten slag 8 is gradually cooled and solidified while suspended from the slag outlet 13, the temperature sensor 30 detects the temperature of the solidified molten slag 8.

In this embodiment, the auxiliary electrodes 16 and 17 are used to heat the solidified molten slag 8 in the discharge passage 9 using arc heat, Joule heat, etc., but when carrying out the present invention, the auxiliary electrodes 16 and 17 16 and 17 are not required; for example, a heating element 40 that can withstand high temperatures, such as molybdenum disilicide, may be embedded in the base 2 made of a refractory material as shown by the broken line in FIG. 1, or, It is also possible to arrange a heating element 40 on the surface of the discharge passage 9 in the direction of flow of the molten slag 8 in place of the auxiliary electrodes 16 and 17. Alternatively, both can be used in common.

Further, the auxiliary electrode 20 is not necessarily required, but may vary depending on the length of the discharge passage 9 and the level of the molten slag 8.
This is determined by the shape of the slag outlet 13, the power of the auxiliary electrodes 16 and 17, etc.

In this embodiment, the shape of the slag outlet 13 is vertical so that the molten slag 8 can rapidly flow out from the discharge passage 9. However, when carrying out the present invention, it is not necessarily necessary to have a vertical structure. Rather, its shape can be changed depending on the fluidity of the molten slag 8 depending on the processing method and processing temperature of the molten slag 8.

Next, control of the waste melting processing furnace using the temperature sensor 30 will be explained.

FIG. 2 shows a sectional view of the main parts of the discharge section of the waste melting processing furnace and an overall configuration diagram of the control device, and FIG. 3 is a system flowchart showing the control of the waste melting processing furnace.

First, this system flowchart starts in step S1. In step S2, the control device 60 connects the fourth
Electric power is supplied to the main heating electrode 5 shown in the conventional example shown in the figure, and the pace metal 7 and molten slag 8 in the furnace main body 1a are brought into a molten state. Time T for the base metal 7 and molten slag 8 in the furnace main body 1a to reach a completely molten state in step S3
1 in the timer, and the timer setting time T1
When the process has passed, in step S4, ``transfer of the waste to be treated from the waste input passage 4 into the furnace main body 1a is started according to the waste transfer program j.''

Then, in step 5, the temperature state of the molten slag 8 is monitored by the temperature sensor 30. At this time, the threshold temperature K [°C] sufficient for the molten slag 8 to have fluid properties is set to a temperature in the vicinity of the range of 1400 to 1600 ["C], for example, and the threshold temperature K [" Determine whether the value is 01 or more. The fact that the output of the temperature sensor 30 is equal to or higher than the threshold temperature K['C] in step S5 means that the molten slag 8 is in continuous slag extraction operation and that even though the furnace has been temporarily stopped,
This means that operation has resumed immediately. At the start of normal furnace operation, molten slag 8 falls from the slag outlet 13,
Since the temperature sensor 30 is not in the lower state, the output of the temperature sensor 30 is the threshold temperature K.
['C] or less, and the process advances to step S6. In step S6, the auxiliary electrodes 16 and 17 of the discharge part 1b are
The controller 60 drives the motor M2 to lower the auxiliary electrodes 16 and 17, and supplies power from the power source 70 to the auxiliary electrodes 16 and 17. At this time, if the molten slag 8 is solidified in the discharge passage 9 and the auxiliary electrodes 16 and 17 cannot make sufficient contact with the molten slag 8, the auxiliary electrode current is changed to the threshold current 1 [A1 In this case, the power to the auxiliary electrodes 16 and 17 is turned off in step S8, and the opening/closing mechanism of the conductive material supply device 18, which uses graphite, iron particles, or a crushed mixture of both as the conductive material, is turned off in step S8. The supply amount of the conductive material is controlled by a timer so that the motor M1 is opened to bring the auxiliary electrodes 16 and 17 into an electrically connected state using the conductive material.

In step S10, the supply amount of the conductive material is changed to the auxiliary electrodes 16 and 1.
When the time limit T2 sufficient to secure the current value of 7 has elapsed, the conductive material supply device 18 is turned off in step 811, and the process returns to step S5. Step S5 to step 81
When the current flowing between the auxiliary electrodes 16 and 17 is secured by the operation in step 1, the routine from step S5 to step S6 and step S7 removes the molten slag 8 that has solidified in the discharge passage 9 due to Joule heat, arc heat, etc. to have liquidity. During this time, the output state of the temperature sensor 30 is monitored in step S5, and the molten slag 8 flows out from the discharge passage 9.
When discharge from the slag outlet 13 is started, the output of the temperature sensor 30 becomes equal to or higher than the threshold temperature K['C], and in step 812 the auxiliary electrodes 16 and 17 are deactivated, and in step S
13, the “continuous slag operation program (not shown)”
to go into.

Therefore, in case of instantaneous furnace shutdown during power outage,
After steps S1 to S4, it is determined in step S5 whether or not the molten slag 8 from the slag outlet 13 has fluidity. When the slag is being discharged from the slag outlet 13, the program goes through step 812 and enters the continuous slag operation program J at step 813.

If the furnace is to be restarted after it has been stopped, step S1
After passing through step S4, it is determined in step S5 whether the molten slag 8 from the slag outlet 13 has fluidity. When the flow of molten slag 8 is cut off, the auxiliary electrodes 16 and 17 are driven by the routine of step S5, step S6, and step S7, and the molten slag 8 in the discharge passage 9 is given fluidity. When the amount of slag increases and starts falling from the slag outlet 13,
In step 812, the drive of the auxiliary electrodes 16 and 17 is canceled, and in step S13, the "continuous slag extraction operation program" is entered.

When the operation is restarted from the solidified state of the base metal 7 and molten slag 8 in the furnace main body 1a, steps S1 to S4 are performed, and in step S5, the output of the temperature sensor 30 is less than the threshold value K ['C], so the step After S5,
The process moves to step S6.

However, the molten slag 8 in the discharge passage 9 has solidified.
In step S7, the current value of the auxiliary electrodes 16 and 17 is set to the threshold value 1.
If it does not rise to [A], the auxiliary electrode 1 is removed in step S8.
6 and 17 is stopped, and step S9 and step S
10. In step 811, a conductive material is supplied between the auxiliary electrodes 16 and 17, and the conductive material generates Joule heat, arc heat, etc. to melt the molten slag 8 solidified in the discharge passage 9. When the melting is completed and the molten slag 8 falls from the slag outlet 13, the program goes through steps S12 from step $5 to step S13'rr continuous slag operation program J, similar to the former case.

In this system flowchart, heating means using Joule heat and arc heat from the auxiliary electrodes 16 and 17 is used as heating means for the discharge part 1b, but in the system flowchart in the case of heating only with the heating element 40,
6 to step S10 may be omitted, and a routine may be performed in which the heating element 40 is heated until the detected value of the temperature sensor 30 becomes equal to or higher than the threshold value K['C] in step S5.

[Effects of the Invention] As described above, the slag outlet control device of the waste melting processing furnace of the present invention detects whether molten slag is flowing out from the slag outlet using a temperature sensor disposed near the slag outlet. Since it is a detection device, it is possible to indirectly detect the continuous flow of molten slag flowing out from the slag outlet of the waste melting processing furnace, and automation of the waste melting processing furnace becomes possible.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the main parts of the discharge section of the waste melting processing furnace according to the embodiment of the present invention, and FIG. 2 is a cross-sectional view of the main parts of the discharge section of the waste melting processing furnace according to the embodiment of the present invention, and a control device. FIG. 3 is a system flowchart showing the control of the waste melting processing furnace, FIG. 4 is a sectional view showing the configuration of the conventional waste melting processing furnace, and FIG. 5 is the discharge section of FIG. 4. FIG. 2 is an enlarged cross-sectional view of main parts. In the figure, 8... Molten slag, 13... Slag outlet, 30... Temperature sensor. In addition, in the figures, the same reference numerals and the same symbols indicate the same or equivalent parts.

Claims (2)

[Claims] (1) In the slag control device of a waste melting processing furnace that processes waste or its incineration ash, a temperature sensor installed near the slag port detects that molten slag is flowing out from the slag port. A slag outlet control device for a waste melting processing furnace, characterized in that: (2) The slag outlet control device for a waste melting processing furnace according to claim 1, wherein the temperature sensor has a radiation temperature detection section.