JP3750881B2 - Ash melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ash melting furnace for melting incineration ash discharged from municipal waste incinerators and various incinerators.
[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, there is a problem of depletion of landfill sites and groundwater contamination due to the elution of toxic heavy metals, so the need for weight reduction / volume reduction and detoxification by melting is increasing.
[0003]
Against this background, ash melting furnaces have been proposed for melting incineration ash discharged from incinerators, etc., using residual carbon, coke, kerosene, and electric power in the incineration ash as heat sources. Has been done.
[0004]
Among these, an ash melting furnace using electric power as a heat source includes a plasma arc heating method and a resistance heating method.
[0005]
The resistance heating type ash melting furnace has a counter electrode in the molten slag, and heats and melts the incinerated ash by electric resistance heat (Joule heat) by direct current or alternating current. (1) High thermal efficiency, (2) Less gas is generated, (3) Flicker is not generated because no arc is generated, and (4) Divided slag separated from molten slag and molten metal can be obtained.
[0006]
FIG. 2 is a longitudinal sectional view of a conventional resistance heating type ash melting furnace. In the figure, a is an ash melting furnace. The furnace wall b of the ash melting furnace a is formed with a water cooling jacket c made of a refractory material such as a refractory brick having a water cooling pipe d embedded therein. e is a furnace lid provided at the top of the ash melting furnace a. The incinerated ash m is charged from an ash charging pipe j provided on a furnace lid e of the ash melting furnace a. The incinerated ash m charged into the ash melting furnace a is heated by the upper electrode h inserted in the furnace lid e of the ash melting furnace a and the furnace bottom electrode i embedded in the furnace bottom of the ash melting furnace a to produce molten slag n. I try to make it. When a required amount of molten slag n is accumulated in the ash melting furnace a, the molten slag n comes out to the outside through the outlet f provided at the lower part of the furnace wall b of the ash melting furnace a by the head pressure applied by its own weight. ing. k is an exhaust pipe provided in the furnace lid e of the ash melting furnace a. o is a molten metal collected at the bottom of the ash melting furnace a, and when a required amount is accumulated like the molten slag n, it is discharged to the outside through the discharge port g. p is a power source for direct current to the upper electrode h and the bottom electrode i, and q and r are electric wires thereof. In addition to this conventional example, there is also a type in which a tap outlet f is provided at the center in the height direction of the furnace wall b of the ash melting furnace a to continuously overflow the molten slag n.
[0007]
A high alumina refractory material having a porosity of 20% to 30% is generally used for the furnace wall b and the furnace lid e of the ash melting furnace a.
[0008]
[Problems to be solved by the invention]
However, in the ash melting furnace as shown in FIG. 2, the furnace wall of the ash melting furnace is formed with a furnace wall having a water cooling jacket with a water cooling pipe embedded therein, so that the refractory material on the furnace wall is the ash melting furnace. There is a problem that the water-cooled tube may be damaged if it is worn away by the high-temperature molten slag inside and left to stand.
[0009]
The present invention was devised to solve the above-described problems, and an object thereof is to provide an ash melting furnace that extends the life of a refractory material without providing a water cooling jacket. is there.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, an ash melting furnace for melting incinerated ash, wherein the outer skin of the furnace wall of the ash melting furnace is cooled by watering , the bottom of the furnace, so as to cool the air, the air that has cooled the bottom of the ash melting furnace so as to air along the nozzle face of the steel shell of the furnace wall outer surface, ash melting furnace, characterized in that it Provided.
[0013]
Further, it is preferable that the water after sprinkling is sprinkled while being received and circulated by a tray provided overhanging at the bottom of the ash melting furnace.
[0014]
According to the configuration of the present invention, water is sprinkled on the outer skin of the furnace wall, and the furnace wall is cooled by evaporation, so that the cooling efficiency of the furnace wall can be increased, and therefore the life of the refractory material Can be lengthened. Cooling by latent heat of vaporization requires less cooling water pipes. In addition, since the bottom of the ash melting furnace is cooled by air cooling, the cooling efficiency of the furnace wall at the bottom of the ash melting furnace can be improved, and warmed air after air cooling rises along the furnace wall In doing so, the evaporation effect of water is enhanced, so that the cooling efficiency can be further enhanced.
[0015]
Further, since the water after sprinkling is received and circulated by a receiving tray provided overhanging at the bottom of the ash melting furnace, it is possible to eliminate the waste of cooling water.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows one embodiment of the present invention, and FIG. 1 is a longitudinal sectional view of a cooling device for an ash melting furnace according to the present invention.
In the figure, 1 is an ash melting furnace for melting incinerated ash. Reference numeral 2 denotes a furnace wall of the ash melting furnace 1, which is formed entirely of refractory bricks and whose outer peripheral surface is formed of an iron skin 3. 4 is a furnace lid provided at the top of the ash melting furnace 1. Reference numeral 5 denotes an upper electrode inserted into an electrode insertion opening provided in the furnace lid 4, and reference numeral 5 a denotes a furnace bottom electrode embedded in the bottom 2 a of the ash melting furnace 1 so as to face the upper electrode 5. 6 is an incineration ash charging pipe provided on the furnace lid 4, and 7 is the charging port. 8 is an exhaust pipe provided in the furnace lid 4 in the same manner as the incineration ash charging pipe 6, and 9 is a discharge port thereof. Reference numeral 10 denotes incineration ash introduced into the ash melting furnace 1 through the incineration ash injection pipe 6. The upper electrode 5 and the furnace bottom electrode 5 a are heated and melted by applying a direct current from a power source to melt the slag 11 and the molten metal 12. The molten slag 11 is fed out from a tap outlet provided in the lower part of the ash melting furnace 1. Further, the molten metal 12 separated from the molten slag 11 and collected at the bottom of the ash melting furnace 1 is solidified, and an arc is generated between the electrodes 5 to melt the metal and then discharged to the outside through the discharge port. The Note that the power supply for energizing the outlet of the molten slag 11, the outlet of the molten metal 12, the upper electrode 5 and the furnace bottom electrode 5 a are not shown, but are substantially the same as the conventional structure. is there.
[0017]
Reference numeral 13 denotes a cooling water tank, which stores water for spraying 17 fed from a water storage tank 25 through a water supply pipe 27 by a water supply pump 26 and melts the incinerated ash 10 on the outer peripheral surface of the iron skin 3 of the furnace wall 2. Sprinkle water. Reference numeral 16 denotes a plurality of annular sprinkling pipes arranged in multiple stages vertically along the outer peripheral surface of the iron skin 3 of the furnace wall 2, and water sprays toward the iron skin 3 of the furnace wall 2 in this watering pipe. Thus, a large number of water spray holes 16a are provided. In addition, the watering angle can be arbitrarily changed by changing the direction of the watering hole 16. Reference numeral 14 denotes a water supply pipe whose upper end is connected to the cooling water tank 13, and the lower end is branched to be connected to each annular sprinkling pipe 16. Then, the cooling water 17 is supplied to the annular sprinkling pipe 16 by the pump 15. Reference numeral 18 denotes a water receiving tray provided overhanging the bottom 2 a of the ash melting furnace 1. The water receiving tray 17 receives the sprinkled water 17 and returns it to the water storage tank 25 through a drain pipe 19 having one end connected to the water receiving tray 18.
[0018]
Reference numeral 20 denotes a surrounding wall provided so as to surround the bottom portion 2 a of the ash melting furnace 1 and the furnace wall 2. Reference numeral 22 denotes a blower pipe having an upper end connected to the bottom of the surrounding wall 20 and a lower end connected to an air cooling fan 21. When the incinerated ash 10 is melted, the cooling air is directed toward the bottom 2 a of the ash melting furnace 1 by the air cooling fan 21. While blowing, the air blown to the bottom 2a of the ash melting furnace 1 is raised along the furnace wall 2 along the furnace wall 2 of the furnace wall 2 and discharged through the exhaust pipe 23. ing. In this way, when the warmed air after air cooling rises along the furnace wall 2, the water evaporation action is enhanced. A drain receiving portion 24 is provided so as to protrude downward at the rising portion of the exhaust pipe 23. The drain received by the drain receiving portion 24 is returned to the water storage tank 25 by the drain pipe 19a.
[0019]
Next, the operation based on the embodiment will be described.
The incinerated ash 10 charged into the ash melting furnace 1 is supplied with direct current from the power source to the upper electrode 5 and the furnace bottom electrode 5a and heated to generate molten slag 11. The incinerated ash 11 melts at 1,200 ° C. in the ash melting furnace 1, but the optimum temperature of the molten slag 11 in the ash melting furnace 1 is as high as 1,200 ° to 1,300 ° C. The salt contained in the incineration ash 10 also evaporates and adheres to the refractory material of the furnace wall 2, penetrates into the refractory material and wears out the refractory material, but toward the outer peripheral surface of the iron skin 3 of the furnace wall 2. Since the cooling water 17 is sprinkled and the furnace wall 2 is cooled, the wear of the refractory material on the furnace wall 2 can be reduced, and the life of the refractory material can be extended. Further, since cooling is performed by evaporation of cooling water, the amount of cooling water used can be reduced. The durability of the furnace can be increased by air cooling the bottom. By circulating water, the amount of cooling water used can be further reduced.
[0020]
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.
[0021]
【The invention's effect】
As described above, according to the present invention, when the incinerated ash charged into the melting furnace is melted, the cooling water is sprayed on the outer peripheral surface of the iron skin of the furnace wall to cool the refractory material. Since it prevents it, there exists an outstanding effect, such as extending the lifetime of a refractory material.
[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 longitudinal sectional view of a conventional ash melting furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ash melting furnace 2 Furnace wall 2a Furnace bottom 3 Iron skin 4 Furnace lid 5 Upper electrode 5a Furnace bottom electrode 6 Incineration ash injection pipe 7 Incineration ash injection port 8 Exhaust pipe 9 Exhaust outlet 10 Incineration ash 11 Molten slag 12 Molten metal 13 Cooling Water tanks 14 and 27 Water supply pipes 15 and 26 Water supply pump 16 Annular water spray pipe 16a Water spray hole 17 Cooling water 18 Water trays 19 and 19a Drain pipe 20 Enclosure 21 Air cooling fan 22 Blower pipe 23 Exhaust pipe 24 Drain receiving section 25 Water tank a Ash Melting furnace b Furnace wall c Water-cooled jacket d Water-cooled tube e Furnace f Depot outlet g Outlet h Upper electrode i Furnace electrode j Incinerated ash charging pipe k Exhaust pipe m Incinerated ash n Molten slag o Molten metal p Power source q, r Electrical wire

Claims (2)

An ash melting furnace for melting incinerated ash, wherein the outer skin of the furnace wall of the ash melting furnace is cooled by watering ,
The bottom of the ash melting furnace is cooled by air cooling,
An ash melting furnace characterized in that air obtained by cooling the bottom of the ash melting furnace is ventilated along the water spray surface of the iron skin on the outer surface of the furnace wall . The ash melting furnace according to claim 1, wherein the water after sprinkling is sprinkled while being received and circulated by a receiving tray provided overhanging at the bottom of the ash melting furnace.

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