JP3921784B2 - Ash melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ash melting furnace for melting and solidifying fly ash and incineration ash generated when municipal waste and industrial waste are incinerated, incineration ash generated when incinerating sewage sludge, coal ash, etc. This relates to an ash melting furnace that effectively reduces the volume, reduces the volume, renders it harmless, and recycles it.
[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 has been proposed that melts incinerated ash discharged from incinerators that use residual carbon, coke, kerosene, and electric power as heat sources. 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. In addition, there are two types of ash melting furnaces of the electric resistance heating type, in which the tap is provided in the middle of the furnace wall and in the lower part of the furnace wall.
[0005]
FIG. 5 is a longitudinal sectional view of a conventional DC electric resistance type ash melting furnace having a tap outlet provided in the middle of the furnace wall.
In the figure, a is an ash melting furnace. b is an ash melting chamber. c is an outlet that continuously overflows the molten slag j provided in the middle of the furnace wall of the ash melting furnace a. d is a metal discharge port provided in the lower part of the furnace wall. e is the main electrode and f is the bottom electrode. m is a power source for passing direct current electricity between the main electrode e and the furnace bottom electrode f, and n and o are the electric wires. g is an ash inlet provided at the top of the ash melting furnace a, and the fly ash and the incinerated ash conveyed by a conveyor (not shown) are charged into the ash melting chamber b. 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 k is a metal layer.
[0006]
[Problems to be solved by the invention]
In the direct current electric resistance type ash melting furnace, since the tap outlet is provided in the middle of the furnace wall, it is not possible to continuously feed the molten slag and molten metal simultaneously. In addition, since the exhaust gas outlet is provided at the top of the furnace, dioxins contained in the ash move into the exhaust gas during ash melting, but the ash solid layer temperature is low, so it is not decomposed and discharged outside the furnace. There is a problem.
[0007]
The present invention was devised to solve the above-described problems. The molten slag and the molten metal are continuously discharged at the same time, and when the liquid level of the molten slag rises, the molten slag is removed. An object of the present invention is to provide an ash melting furnace that can overflow and prevent the liquid level of molten slag from rising excessively and can continuously decompose dioxins contained in exhaust gas in an ash melting chamber.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, an ash melting furnace for performing ash melting by applying a direct current between a main electrode inserted from the furnace top and a furnace bottom electrode provided at the furnace bottom, An outlet that is provided at the bottom of the furnace wall to continuously melt molten slag and molten metal, and an auxiliary outlet that is provided in the middle of the furnace wall and that overflows when the level of the molten slag rises. And a combustor that is connected to the auxiliary outlet and burns CO gas generated by ash melting, and is provided in the vicinity of the auxiliary outlet in the ash melting furnace and heats the molten slag that overflows from above And an auxiliary burner that burns CO gas, and an auxiliary electrode that is inserted from the top of the furnace so that the lower end is located in the vicinity of the tap hole, and adjusts the properties of the metal when discharging the metal deposited on the bottom of the furnace, Provided by an ash melting furnace consisting of It is.
[0009]
According to a preferred embodiment of the present invention, the auxiliary burner is a propane gas burner.
[0010]
Next, the operation of the present invention will be described.
Fly ash and incinerated ash charged into the ash melting chamber are heated to a molten slag by the main electrode and the furnace bottom electrode disposed in the ash melting chamber. Here, the ash is separated into a lower molten slag layer and an ash solid layer that floats thereon. During operation, molten slag and molten metal are continuously discharged from the outlet. When the metal is not sufficiently discharged and the metal level rises, the metal is heated by the auxiliary electrode to adjust the properties of the metal and then discharged. When the liquid level of the molten slag rises, it overflows from the auxiliary outlet. When the molten slag overflows, the molten slag is heated from above by an auxiliary burner. The CO gas generated by the oxidation of the carbon used for the main electrode in the ash melting chamber is heated by the molten slag and the auxiliary burner when passing through the auxiliary outlet and connected to the auxiliary outlet. Then, it is led to a combustor provided to burn. Dioxin contained in the ash and transferred to the exhaust gas is decomposed by the high temperature of the molten slag when passing over the molten slag. Since the molten metal is discharged together with the molten slag, the molten metal need not be discharged separately from the molten slag, and the ash melting furnace can be operated continuously. Since the molten slag overflows when the liquid level of the molten slag rises, it is possible to easily monitor the molten slag and manage the liquid level. In addition, since the decomposition of dioxins contained in the exhaust gas is continuously performed in the ash melting chamber, it is not necessary to newly provide equipment for dioxin decomposition.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
1 to 3 show an embodiment of the present invention. FIG. 1 is a plan view of an ash melting furnace according to the present invention, FIG. 2 is a view taken along arrow AA in FIG. 1, and FIG. FIG.
1 to 3, reference numeral 1 denotes an ash melting furnace for melting fly ash and incinerated ash. 2 is an ash melting chamber having an ash inlet 7 at the top (FIGS. 2 and 3). Fly ash and incineration ash are transported by a conveyor (not shown) and the like and charged into the ash melting chamber 2 from the ash charging port 7. Denoted at 3 is an outlet for continuously and simultaneously melting molten slag 13 and molten metal 14 provided in the lower part of the furnace wall (FIGS. 1 and 2). 4 is an auxiliary outlet for overflowing the molten slag 13 provided in the projecting portion 1a in the middle of the furnace wall, which also serves as an exhaust gas outlet (exhaust outlet). It can also be used as a continuous outlet for breakdowns and repairs (Figs. 1 and 3). The exhaust gas generated by heating the ash solid layer 12 in the ash melting chamber 2 passes through the auxiliary outlet 4 and passes through to the combustor 9 connected to the auxiliary outlet 4. And burned (FIGS. 1 and 3). 5 is a main electrode provided so as to pass through the furnace lid at the top of the ash melting chamber 2, and 6 is a furnace bottom electrode embedded in the bottom of the ash melting chamber 2 so as to face the main electrode 5 vertically (see FIG. 2, FIG. 3). Reference numeral 8 denotes an auxiliary electrode provided so as to penetrate the furnace lid at the top of the ash melting chamber 2 and have a lower end positioned in the vicinity of the tap outlet 3. When the metal level rises due to deposition, the metal 14 is heated by energization to adjust the properties of the metal 14 (FIGS. 1 and 2). The auxiliary electrode 8 can adjust not only the properties of the metal 14 but also the properties of the molten slag 13. 10 is an upper burner 1 in the vicinity of the ash melting chamber 2, and is an auxiliary burner that heats the molten slag 13 that overflows from above and burns CO gas. Fuel is used (Fig. 3). Reference numeral 11 denotes a discharge port for the molten slag 13 which is provided at the lower end of the combustor 9 and overflows. The molten slag 13 is collected by a tray (not shown) provided below the discharge port 11. Reference numeral 15 denotes a power source for energizing the main electrode 5, the furnace bottom electrode 6 and the auxiliary electrode 8, and 16, 17 and 18 are electric wires thereof (FIG. 2). Reference numeral 19 denotes a flow of exhaust gas (FIG. 3).
[0012]
FIG. 4 is an enlarged cross-sectional view of the tap mouth 3.
The spout 3 is constituted by a copper jacket 1c. Reference numeral 1 b denotes a brick that forms the furnace wall of the ash melting furnace 1. In addition, when the molten slag 13 and the molten metal 14 are continuously brewed, 20 is a control rod that controls the amount of brewing, and its tip is cooled and controlled close to and away from the brewing port 3. The operation of the control rod 20 is performed by a control device (not shown) disposed in the vicinity of the tap hole 3.
[0013]
Next, the operation of the embodiment will be described.
The fly ash and incinerated ash charged into the ash melting chamber 2 are heated to the molten slag 13 by the main electrode 5 and the furnace bottom electrode 6 disposed in the ash melting chamber 2. Here, the ash is separated into a lower molten slag layer 13 and an ash solid layer 12 that floats thereon. During operation, the molten slag 13 and the molten metal 14 are continuously discharged from the outlet 3. When the metal 14 is not sufficiently discharged and the metal level rises, the metal 14 is heated by the auxiliary electrode 8 to adjust the properties of the metal 14 and discharged. When the liquid level of the molten slag 13 rises, it overflows from the auxiliary outlet 4. When the molten slag 13 overflows, the molten slag 13 is heated from above by the auxiliary burner 10. The CO gas generated by the oxidation of the carbon used for the main electrode 5 in the ash melting chamber 2 is heated by the molten slag 13 and the auxiliary burner 10 when passing through the auxiliary outlet 4 in the lateral direction, It is guided to a combustor 9 connected to the outlet 4 and burns. The dioxin contained in the ash and transferred to the exhaust gas is decomposed by the high temperature of the molten slag 13 when passing over the molten slag 13. Thus, since the molten metal 14 is discharged along with the unloading of the molten slag 13, it is not necessary to discharge the molten metal 14 separately from the unloading of the molten slag 13, and the operation of the ash melting furnace 1 is continuously performed. Since the molten slag 13 overflows when the liquid level of the molten slag 13 rises, the monitoring of the molten slag 13 and the management of the liquid level can be facilitated. Further, since the decomposition of dioxins contained in the exhaust gas is continuously performed in the ash melting chamber 2, there is no need to newly provide a facility for dioxin decomposition.
[0014]
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.
[0015]
【The invention's effect】
As described above, according to the present invention, the molten slag and the molten metal are continuously discharged at the same time, the molten slag whose liquid level has risen is overflowed to prevent the liquid level from rising excessively, and is contained in the exhaust gas. The dioxins can be decomposed continuously in the ash melting chamber, and thus excellent effects are exhibited.
[Brief description of the drawings]
FIG. 1 is a plan view of an ash melting furnace according to the present invention.
FIG. 2 is a view taken in the direction of arrows AA in FIG.
FIG. 3 is a view taken along arrow BB in FIG. 1;
FIG. 4 is an enlarged cross-sectional view of a tap opening.
FIG. 5 is a longitudinal sectional view of a conventional ash melting furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ash melting furnace 1a Protrusion part 2 Ash melting chamber 3 Outlet 4 Auxiliary exit 5 Main electrode 6 Furnace electrode 7 Ash inlet 8 Auxiliary electrode 9 Combustor 10 Auxiliary burner 11 Exhaust outlet of molten slag 12 Ash Solid layer 13 Molten slag layer 14 Metal layer 15 Power source 16, 17, 18 Electric wire

Claims (2)

A ash melting furnace for performing the ash melting by direct current energization between the furnace bottom electrode provided on the inserted main electrode and the furnace bottom of the furnace top, is horizontally formed in the lower part of the furnace wall, molten slag And a molten metal outlet at the same time, and a channel outlet horizontally drilled in a projecting portion horizontally disposed in the middle of the furnace wall, and has an opening smaller than the channel, and an exhaust An auxiliary outlet that overflows when the gas is discharged and the liquid level of the molten slag rises, and is connected to the auxiliary outlet, and has a bottomed cylindrical shape having a bottom portion just below the auxiliary outlet. The bottom portion is provided with a molten slag discharge port for discharging molten slag overflowed from the auxiliary outlet, and is provided in the combustor for burning the CO gas generated by the ash melting, and in the protruding portion. of the ceiling portion of the flow path, it is provided upstream of the auxiliary tapping port, over While heating the flow to molten slag from above, an auxiliary burner for burning CO gas generated in the furnace, the lower end is inserted from the furnace top so that the position facing the furnace bottom in the vicinity of the tapping hole, the furnace When the level of the metal deposited on the bottom rises, an auxiliary electrode that adjusts the properties of the metal by energizing it to promote the discharge of the metal when energized , and the above-mentioned outlet that continuously outputs molten slag and molten metal simultaneously It is provided with a control rod that is installed horizontally and is controlled by controlling the amount of slag in the ash melting furnace by controlling the amount of slag by approaching and separating from the throat. An ash melting furnace.   The ash melting furnace according to claim 1, wherein the auxiliary burner is a propane gas burner.

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