JP3757409B2 - Ash melting furnace and method for forming bottom electrode of ash melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ash melting furnace that melts fly ash and incineration ash generated when municipal waste and industrial waste are incinerated, and an operation method thereof.
[0002]
[Prior art]
Wastes such as municipal waste and sewage sludge were incinerated at an incineration facility, and the resulting fly ash and incineration ash 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, an ash melting furnace has been proposed that melts fly ash and incineration ash discharged from incinerators that use residual carbon, coke, kerosene, and electric power as heat sources. Processing is in progress. 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]
FIG. 2 is a longitudinal sectional view of a conventional resistance heating ash melting furnace.
In the figure, a is an ash melting furnace. b is an ash melting chamber. c is a tap outlet provided in the lower part of the ash melting furnace a, and d is a metal discharge port. e is a main electrode. f is a furnace bottom electrode provided at the bottom so as to face the main electrode e vertically. 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 j is a molten slag. k is a metal layer. 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.
[0005]
[Problems to be solved by the invention]
The bottom electrode of the ash melting furnace is made of a conductive refractory impregnated with carbon, but the bottom electrode made of a conductive refractory is subject to various restrictions during the construction of the furnace. Since the resistance value of the bottom electrode is high, energy consumption in the furnace bottom electrode portion increases, and heat generation causes a decrease in the life of the furnace bottom electrode.
[0006]
The present invention was devised to solve the above-mentioned problems, eliminates the bottom electrode made of conductive refractory, prevents deterioration of the bottom electrode of the ash melting furnace, and extends the life of the furnace. The purpose of this is to reduce the amount of heat generated at the bottom electrode of the furnace, save energy consumption, and improve the thermal efficiency of the furnace.
[0007]
[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, The furnace bottom electrode is provided with an ash melting furnace comprising a steel plate laid on a refractory brick at the bottom of the furnace and a cast iron metal layer melted and deposited on the steel plate.
[0008]
Next, the operation of the present invention will be described.
The bottom of the ash melting furnace is constructed with refractory bricks. A steel plate is inserted and laid on the refractory brick at the bottom of the furnace. When a new ash melting furnace is operated, cast iron scrap is placed on the steel plate and placed on the steel plate prior to operation, and an arc is generated to melt and deposit the scrap to form a cast iron metal layer. To do. A furnace bottom electrode is formed of a steel plate and a cast iron metal layer. Ash melting is performed after the furnace bottom electrode is formed on the refractory brick at the furnace bottom. During the ash melting operation, the metal component contained in the ash settles and accumulates as a molten metal on the cast iron metal layer, and functions as the furnace bottom electrode together with the furnace bottom electrode. The electrical resistance of the steel plate and metal layer is extremely lower than that of conductive refractories, so the amount of heat generated in this part is small, and therefore the furnace bottom electrode is less deteriorated, the furnace life is extended, and the consumption is increased. It can save energy and improve the thermal efficiency of the furnace.
[0009]
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, 1 is an ash melting furnace which melts fly ash and incinerated ash. 1a is the bottom of the ash melting furnace 1 and is composed of refractory bricks. 2 is an ash melting chamber. 3 is a furnace bottom electrode. The furnace bottom electrode 3 is mounted on the bottom 1a of the ash melting furnace 1 made of refractory bricks by placing a steel plate 6 laid so as to face the main electrode 5, and scraps of cast iron on the steel plate 6. It is formed from a cast iron metal layer 7 formed by depositing and melting and depositing scrap and the like. The steel plate 6 may be laid on the entire surface of the bottom 3 of the ash melting furnace 1 or only on the portion facing the main electrode 5. Denoted at 4 is an outlet for extracting molten slag 9 provided at the lower portion of the furnace wall. Reference numeral 5 denotes a main electrode provided so as to penetrate the top of the ash melting furnace 1. Reference numeral 8 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 9 in an unmelted state. 10 is a metal layer in which the iron contained in the ash melts and settles and accumulates on the furnace bottom electrode 3 during operation, and serves as a furnace bottom electrode integrally with the lower cast iron metal layer 7. 11 is a power source for direct current to the main electrode 5 and the furnace bottom electrode 3, and 12 and 13 are electric wires thereof.
[0010]
Next, the operation of this embodiment will be described.
The bottom 1a of the ash melting furnace 1 is constructed with refractory bricks. The steel plate 6 is inserted and laid on the refractory brick of the furnace bottom 1a. When the ash melting furnace 1 is newly operated, cast iron scrap or the like is placed and placed on the steel plate 6 prior to the operation, and an arc is generated to melt and deposit the scrap or the like to form a cast iron metal layer. 7 The furnace bottom electrode 3 is formed of a steel plate 6 and a cast iron metal layer 7. Ash melting is performed after the furnace bottom electrode 3 is formed on the refractory brick of the furnace bottom 1a. During the ash melting operation, the metal component contained in the ash settles and accumulates on the cast iron metal layer as the molten metal 10 and functions as the furnace bottom electrode together with the furnace bottom electrode 3. Since the electrical resistance of the steel plate 6 and the metal layer 7 is extremely lower than that of the conductive refractory, the amount of heat generated in this portion is small. Therefore, the furnace bottom electrode 3 is less deteriorated and the life of the furnace 1 is extended. In addition to saving energy consumption, the thermal efficiency of the furnace 1 can be improved.
[0011]
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.
[0012]
【The invention's effect】
As described above, according to the present invention, the bottom of the ash melting furnace is constructed of refractory bricks, and is formed of a steel plate laid on the refractory brick and a cast iron metal layer melted and deposited on the steel plate. Excellent effects such as low heat generation in the furnace bottom electrode, preventing deterioration of the furnace bottom electrode, extending the life of the furnace, saving energy consumption, and improving the thermal efficiency of the furnace Play.
[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 resistance heating ash melting furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ash melting furnace 2 Ash melting chamber 3 Furnace bottom electrode 4 Outlet 5 Main electrode 6 Steel plate 7 Cast iron metal layer 8 Ash solid layer 9 Molten slag layer 10 Metal layer 11 Power supply 12, 13 Electric wire 14 Ash inlet 15 Exhaust gas exhaust Exit

Claims (2)

An ash melting furnace that melts ash by applying direct current between the main electrode inserted from the furnace top and the furnace bottom electrode provided at the furnace bottom, and the furnace bottom electrode is laid on a refractory brick at the furnace bottom Ash melting characterized in that it is composed of a cast steel sheet and a cast iron metal layer placed on the steel sheet by placing and placing a cast iron scrap on the steel sheet, generating an arc and melting it Furnace. A method for forming a bottom electrode of an ash melting furnace in which ash melting is performed by applying a direct current between a main electrode inserted from the top of the furnace and a bottom electrode provided at the bottom of the furnace. A step of laying a steel plate, a step of placing and placing a cast iron scrap on the steel plate, an arc is generated between the scrap and the main electrode, and the scrap is melted and deposited. And a step of forming a cast iron metal layer. A method for forming a bottom electrode of an ash melting furnace.

Images