JP3744669B2 - Ash melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ash melting furnace that melts and solidifies fly ash and incineration ash generated when municipal waste and industrial waste are incinerated. In particular, the present invention is effective in reducing weight, reducing volume, detoxifying and recycling by melting. It relates to an ash melting furnace.
[0002]
[Prior art]
Municipal waste, sewage sludge, and other wastes were incinerated at incineration facilities, and the resulting incinerated ash and dust were conventionally disposed of in landfills. However, due to the problems of landfill depletion and groundwater contamination due to the elution of toxic heavy metals, there is an increasing need for weight reduction / volume reduction, detoxification and recycling by melting.
[0003]
Against this background, an ash melting furnace that melts incinerated ash discharged from incinerators that use residual carbon, coke, kerosene and electric power as the heat source has been proposed. It has been broken. Among these, there are a plasma arc heating method and an electric resistance heating method as an ash melting furnace using electric power as a heat source.
[0004]
The electric resistance heating method is characterized in that the molten metal is quiet because of electric resistance heating, the metal component and the volatile heavy metal are well separated, and the slag quality is better than other melting methods.
[0005]
FIG. 3 is a longitudinal sectional view of a conventional ash melting furnace.
In the figure, a is an ash melting furnace. b is an ash melting chamber. c is a tap outlet provided at the lower part of the ash melting furnace a, and d is a molten metal discharge port provided at the bottom of the ash melting furnace a. e is the main electrode and f is the bottom electrode. m is a power source for flowing DC electricity between the main electrode e and the bottom electrode f, and n and o are the electric wires. g is an ash charging port provided at the top of the ash melting furnace a, and the fly ash and incinerated ash conveyed by a conveyor (not shown) are charged into the ash melting furnace a. h is an exhaust gas outlet provided at the top of the ash melting furnace a. i is an ash solid layer such as fly ash or incinerated ash charged into the ash melting chamber b, and j is a molten slag. k is a metal layer.
[0006]
[Problems to be solved by the invention]
In the above ash melting furnace, when ash containing a significant amount of iron, alkali metal, alkaline earth metal, etc. is melted with fly ash, these components remain in the slag, and the chemical stability of the slag Reduce sex. On the other hand, when recycling slag, it is desired to stably produce a slag having a component according to the purpose. At this time, a slab property adjusting agent may be added before the ash is put into the ash melting furnace, but when doing so, the constant becomes large when property control is performed, and the response is delayed when the change in the ash properties is large. .
[0007]
The present invention was devised to solve the above-mentioned problems, and while reducing weight, reducing volume, making it harmless, adjusting the properties of the slag within a certain range, and stabilizing the quality of the slag It is an object of the present invention to provide an ash melting furnace that can be maintained and manufactured in order to recycle slag.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, there is provided an ash melting furnace for melting fly ash and incinerated ash, wherein the ash melting furnace has an ash melting chamber having an ash inlet at the top, and an exhaust at the top. The ash melting chamber and the slag property adjusting chamber are connected to each other with a gas discharge port and a slag property adjusting chamber having an outlet that overflows molten slag at the middle. Concatenated by a passage, the main electrode and the bottom electrode at the bottom of the ash melting chamber, the auxiliary electrode at the top and the bottom electrode at the bottom of the slag property adjustment chamber are arranged so as to face each other vertically, In addition, a molten slag property adjusting device is provided in the vicinity of the slag property adjusting chamber, and the molten slag property adjusting device includes a detector that detects the property of the molten slag disposed in the vicinity of the tap outlet, and a regulator supply device. From the control device that controls the regulator supply device by the signal from the detector Ash melting furnace is provided that is made.
[0009]
According to a preferred embodiment of the present invention, a partition plate for preventing the slag property adjusting agent floating on the upper surface of the molten slag from being disposed on the slag property adjusting chamber side of the tap outlet is disposed.
[0010]
According to another preferred embodiment of the present invention, the furnace bottom electrodes respectively disposed in the ash melting chamber and the slag property adjusting chamber are respectively used as the furnace bottom electrode common to the ash melting chamber and the slag property adjusting chamber.
[0011]
According to another preferred embodiment of the present invention, the slag property modifier is cinnabar sand mainly composed of silicon (Si).
[0012]
Next, the operation of the present invention will be described.
The ash melting furnace is composed of two chambers, an ash melting chamber and a slag property adjusting chamber. First, fly ash and incinerated ash charged into the ash melting chamber are heated to a molten slag by a main electrode and a furnace bottom electrode disposed in the ash melting chamber in a large ash melting chamber. Here, the ash is separated into a lower molten slag layer and an ash solid layer that floats thereon. The molten slag flows into the small slag property adjusting chamber through the communication path of the partition wall, and is heated again by the auxiliary electrode and the furnace bottom electrode disposed in the slag property adjusting chamber. When unloading from the unloading port, a slag property adjusting agent is added to the slag property adjusting chamber while continuously detecting the properties of the molten slag by a detector disposed in the vicinity of the unloading port. The molten slag is adjusted to an appropriate basicity by using a slag property adjusting agent, and is then discharged by overflow. The exhaust gas generated by heating the ash solid layer in the ash melting chamber passes through the communication hole of the partition wall, passes through the slag property adjusting chamber, and is discharged from the exhaust gas discharge port provided at the top of the slag property adjusting chamber. As described above, the slag property adjusting agent is added in the vicinity of the tap and the slag property is continuously detected at the tap, so even when the ash properties to be put into the ash melting furnace change, Therefore, it is easy to control the properties, adjust the basicity of the slag within the required range, stably maintain the quality of the slag, and provide slag suitable for slag recycling. Can be manufactured.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an embodiment of the present invention and is a longitudinal sectional view of an ash melting furnace according to the present invention.
In FIG. 1, reference numeral 1 denotes an ash melting furnace for melting fly ash and incinerated ash. An ash melting chamber 2 having an ash charging port 3 at the top and an exhaust gas discharge port (exhaust port) 4 at the top by a partition wall 21. And a slag property adjusting chamber 6 having an outlet 5 through which the molten slag 17 overflows in the middle. Fly ash and incineration ash are transported by a conveyor (not shown) and the like and are put into the ash melting chamber 2 from the ash inlet 3. An outlet 5 is provided in the middle of the ash melting furnace 1 to overflow the molten slag layer 17b and keep the level of the molten slag layer 17 constant. Reference numeral 7 denotes a communication path provided in the partition wall 21 so that the ash melting chamber 2 and the lower part of the slag property adjusting chamber 6 communicate with each other. The molten slag 17 melted in the ash melting chamber 2 passes through the communication path 7. Into the slag property adjusting chamber 6. 17 a is a molten slag that has flowed into the slag property adjusting chamber 6, and 17 b is a molten slag discharged from the tap outlet 5. 21b is a communication hole provided in the upper part of the partition wall 21, and the exhaust gas generated by heating the ash solid layer 16 in the ash melting chamber 2 passes through the communication hole 21b, passes through the slag property adjustment chamber 6, and passes through the slag property adjustment chamber. 6 is discharged from the exhaust port 4 at the top. Reference numeral 8 denotes a main electrode provided so as to penetrate the furnace lid at the top of the ash melting chamber 2, and reference numeral 10 denotes a furnace bottom electrode embedded in the bottom of the ash melting chamber 2 so as to face the main electrode 8 vertically. Reference numeral 19 denotes a power source for direct current supply to the main electrode 8 and the furnace bottom electrode 10, and 19a and 19b denote electric wires thereof. Reference numeral 9 denotes an auxiliary electrode provided so as to penetrate the furnace lid of the slag property adjusting chamber 6, and reference numeral 11 denotes a furnace bottom electrode embedded in the bottom of the slag property adjusting chamber 6 so as to face the auxiliary electrode 9 vertically. Reference numeral 20 denotes a power source for direct current to the auxiliary electrode 9 and the furnace bottom electrode 11, and reference numerals 20a and 20b denote electric wires thereof. It is not necessary to provide two power sources 19 and 20, and the current value of each power source may be adjusted individually by one power source, and the partition plate 21a on the furnace bottom is removed and provided separately. The furnace bottom electrodes 10 and 11 may be shared.
[0014]
12 is a slag property adjusting device provided in the vicinity of the slag property adjusting chamber 6, and includes a detector 13 for detecting the property of the molten slag 17a provided in the vicinity of the tap outlet 5 and a furnace lid at the top of the slag property adjusting chamber 6. It is composed of an adjusting agent supply device 14 such as Si-based dredged sand provided so as to penetrate and a control device 12a that controls the adjusting agent supply device 14 by a signal from the detector 13. For example, an X-ray analyzer may be used as the detector 13. The X-ray analyzer is arranged on the outside of the slag property adjusting chamber 6 so as to face the tap outlet 5 with a predetermined interval, and irradiates X-rays toward the molten slag 17a to be put out. Fluorescence generated from the molten molten slag 17a is received to detect the property of the molten slag 17a.
[0015]
Reference numeral 15 denotes a molten metal discharge port provided at the bottom of the ash melting furnace 1. Reference numeral 16 denotes an ash solid layer such as fly ash or incinerated ash charged into the ash melting chamber 2 and floats on the molten slag layer 17 in an unmelted state. Reference numeral 18 denotes a molten metal layer separated from the molten slag 17 and accumulated at the bottom of the ash melting chamber 2. In the molten metal layer 18, the electrical resistance is extremely smaller than that of the molten slag layer 17, so no Joule heat is generated in this portion, most of the metal is solid, and only the upper surface is slightly melted. The molten metal layer 18 generates an arc between the main electrode 8 and the auxiliary electrode 9 at an appropriate time to melt the metal, and then discharges it to the outside through the metal discharge port 18. Reference numeral 17b denotes molten slag that has overflowed from the spout 5 and dropped.
[0016]
FIG. 2 is a view showing another embodiment of the present invention, and is an enlarged view of a part of FIG.
In FIG. 2, 22 is a partition plate arranged so as to protrude to the slag property adjusting chamber 6 side of the tap outlet 5 of the slag property adjusting chamber 6, and the lower end thereof is immersed in the molten slag layer 17a, The slag property adjusting agent supplied on the slag 17a is prevented from flowing out from the tap outlet 5.
[0017]
Next, the operation of the embodiment of the present invention will be described.
The ash melting furnace 1 is composed of two chambers, an ash melting chamber 2 and a slag property adjusting chamber 6, and the fly ash and incinerated ash charged into the ash melting chamber 2 are first separated from the main electrode 8 and the furnace bottom in the ash melting chamber 2. The molten slag 17 is formed by heating the electrode 10 at a temperature of about 1,100 ° C. Next, the molten slag 17 flows into the slag property adjusting chamber 6 through the communication path 7 and is heated again by the auxiliary electrode 9 and the furnace bottom electrode 11. When tapping from the spout 5, the basicity of the molten slag 17 a is continuously detected by the detector 13 disposed in the vicinity of the spout 5. When the detected basicity of the molten slag 17a is larger than the target value, a slag property adjusting agent such as dredged sand mainly composed of Si is added to the slag property adjusting chamber 6 to adjust the basicity of the molten slag 17a. And then output due to overflow. By adjusting the basicity, a soluble component is hardly eluted from the solidified slag. Thus, the slag suitable for recycling of slag can be manufactured by adjusting the property of the slag within a certain range and maintaining the quality of the slag stably.
[0018]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.
[0019]
【The invention's effect】
As described above, according to the present invention, since the properties of the molten slag to be extracted are adjusted by the slag property modifier, the molten slag can be adjusted within a certain range, and the quality of the slag can be stably maintained. Thus, the outstanding effect which can manufacture the slag suitable for recycling of slag is produced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of an ash melting furnace according to the present invention.
FIG. 2 is a partially enlarged view of FIG. 1 showing another embodiment of the present invention.
FIG. 3 is a longitudinal sectional view of a conventional ash melting furnace.
[Explanation of symbols]
1 Ash melting furnace 2 Ash melting chamber 3 Ash inlet 4 Exhaust gas outlet (exhaust outlet)
5 Outlet 6 Slag property adjusting chamber 7 Communication path 8 Main electrode 9 Auxiliary electrodes 10, 11 Furnace bottom electrode 12 Slag property adjusting device 13 Detector 14 Adjusting agent supply device 15 Metal outlet 16 Ash solid layer 17, 17a Molten slag 18 Molten metal 19, 20 Power supply 21, 21a Partition wall 21b Communication hole 22 Partition plate

Claims (4)

An ash melting furnace for melting fly ash and incinerated ash, the ash melting furnace having an ash melting chamber having an ash inlet at the top, an exhaust gas discharge port at the top and an overflow of molten slag at the middle The slag property adjusting chamber is composed of two chambers having a tap outlet, and the ash melting chamber and the slag property adjusting chamber are connected to each other by a communication passage. The ash melting chamber has a main electrode at the top and a furnace at the bottom. The bottom electrode is disposed in the slag property adjusting chamber so that the auxiliary electrode and the furnace bottom electrode are opposed to each other in the upper and lower portions, and a molten slag property adjusting device is provided in the vicinity of the slag property adjusting chamber, The molten slag property adjusting device includes a detector for detecting the property of the molten slag disposed in the vicinity of the outlet, a regulator supplying device for adding the slag property adjusting agent to the slag property adjusting chamber, and a signal from the detector. A control device for controlling the regulator supply device by Ash melting furnace, characterized in that it is al configured.   The ash melting furnace according to claim 1, wherein a partition plate for preventing the slag property adjusting agent floating on the upper surface of the molten slag is disposed on the slag property adjusting chamber side of the tap outlet. The ash melting furnace according to claim 1 or 2, wherein the furnace bottom electrodes respectively disposed in the ash melting chamber and the slag property adjusting chamber are the furnace bottom electrodes common to the ash melting chamber and the slag property adjusting chamber. The ash melting furnace according to any one of claims 1 to 3 , wherein the slag property adjusting agent is silica sand mainly composed of silicon (Si).

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