JPH04251106A - Ash melting furnace - Google Patents

Abstract

PURPOSE:To provide an ash melting furnace of a low cost that can be operated stably at a low running cost by using the incineration ash which contains unburned carbon as a heat source. CONSTITUTION:A molten ash storage section 63 is provided in the inside of a vessel-shaped furnace main body 27 into which incineration ash 25 containing unburned carbon is charged, a heating device is provided in the furnace main body 27, and an oxygen supply nozzle 40 that supplies combustion air or oxygen 39 to the molten ash storage section 43 is provided.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ash melting furnace in which incinerated ash discharged from an incinerator is melted to reduce its volume.

0002

[Prior Art] In recent years, incineration ash discharged from incinerators that incinerate municipal waste and other wastes has been melted and solidified at high temperatures in order to reduce volume, make it non-polluting, and recycle resources. To,
Ash melting furnaces are used.

An example of a conventional ash melting furnace will be described with reference to FIG. An arc is generated by an arc electrode 4 charged from above, and the incinerated ash 3 is melted by the heat of the arc, and a molten metal 5 of the incinerated ash 3 accumulated at the bottom of the furnace body 2 is formed at the bottom of the furnace body 2. The liquid is discharged from a discharge port 6 and supplied to a solidification device (not shown). There is also a method in which the arc electrode 4 is immersed in the molten metal 5 as the melting progresses, and electricity is applied to the molten metal 5 to continue the melting using the electric resistance heat of the molten metal 5.

FIG. 3 shows another example of a conventional ash melting furnace, in which incinerated ash 3 from an incinerator (not shown) is fed into the furnace body 9 from supply ports 7 and 8 formed at the top, and the furnace body 9 The surface of the incinerated ash 3 stored inside the furnace body 9 is melted by the flame of the burner 10 charged into the interior from above, and the molten metal 5 on the surface of the molten incinerated ash 3 is discharged through a discharge port formed at the bottom of the furnace body 9. 11 and supplied to a solidification device (not shown).

[0005] Both of these two conventional examples are devices that rely on other heat sources to melt the incinerated ash 3, which has been completely burned to leave almost no unburned carbon, and have already been used in various fields. It is being carried out in In the ash melting furnace shown in Fig. 2 above, a large amount of electric power must be constantly input to the arc electrode 4 (or electrical resistance electrode) that melts the incinerated ash 3, and in the ash melting furnace shown in Fig. 3, the incineration In order to melt the ash 3, a large amount of fuel must be constantly fed into the burner 10, which increases running costs.

Therefore, as shown in FIG. 4, by controlling the degree of combustion of the waste 13, a desired proportion of unburned carbon remains in the incinerated ash 3, and the incinerated ash discharged from the incinerator 12 is An ash melting furnace 14 has been developed that uses combustion heat of unburned carbon contained in ash as a heat source to melt the ash. Incidentally, in order to leave unburned carbon in the incineration ash 3, for example, a rotary cylindrical incinerator 12 is used, the details of which are as follows.
It is disclosed in Japanese Patent Application No. 62-232646.

Further, a typical structural example of the ash melting furnace 14 is shown in FIG. 4, in which the incinerated ash 3 containing unburned carbon discharged from the incinerator 12 is introduced into the ash melting furnace 14. At the inlet of the ash melting furnace 14, unburned carbon is combusted by the combustion air 15, and the incinerated ash 13 is heated and melted by this combustion heat. The molten metal 5 generated at this time flows diagonally downward through the hearth 16 and is discharged from the discharge end 17 to a solidification device (not shown) in the next step.

By the way, in this type of conventional example, unburned carbon is burned by the combustion air 15 at the inlet of the ash melting furnace 14, so that the molten metal 5 flowing through the hearth 16 has a sufficient amount of heat. There was a problem in that the molten metal 5 that was not supplied adhered to the hearth 16 and solidified, thereby clogging the inside of the ash melting furnace 14. Also,
This phenomenon appeared not only on the hearth 16 but also on the furnace wall, making it impossible to stabilize the operation. As a result, improvements have continued since then,
As shown in FIG. 5, the ash melting furnace that has been developed in recent years has a supply port 18 for the incinerated ash 3 containing unburned carbon at the upper end, and an outlet 19 for the molten metal 5 at the lower end. Furnace body 20 made of refractory material whose entire body is slanted downward, and furnace body 20
It is composed of a plurality of ceramic hearth plates 21 arranged in a stepped manner inside, a high-temperature electric heater 22 provided inside each hearth plate 21, and an air nozzle 24 that blows out combustion air 23. The incinerated ash 3 containing unburned carbon introduced from the port 18 is heated to a high temperature by a high-temperature electric heater 22 provided inside the hearth plate 21, and high-temperature combustion air 23 is ejected into the incinerated ash 3 from the air nozzle 24. By doing so, the unburned carbon contained in the incineration ash 3 is combusted, and once the atmospheric temperature in the furnace reaches a high enough temperature to continue combustion, heating by the high-temperature electric heater 22 is stopped and the combustion heat of the unburned carbon is used as the only heat source. The incinerated ash 3 is combusted, and the molten metal 5 that has been combusted and melted is made to flow down from above to the bottom along each grate plate 21 arranged in a stepwise manner, and as the molten metal 5 flows down, the incinerated ash 3 The molten metal 5 is transferred downward, and the molten metal 5 is discharged from the lowest hearth plate 21 to the discharge port 19, and is supplied to an external solidification device (not shown). Furthermore, a pusher 24' is incorporated in the furnace body 20, and the molten metal 5 is pushed inside the furnace body 20.
When the adhered matter is solidified, the pusher 24' is used to peel off the adhered matter and discharge it.

[0009]

However, the ash melting furnace shown in FIG. 5 has the following problems.

That is, the combustion heat of unburned carbon is used as a heat source to continuously melt the incinerated ash 3 on each hearth plate 21 provided stepwise throughout the inside of the furnace body 20, and the resulting molten metal 5 is transferred stepwise. In order to cause the flow to flow sequentially from above to below along each of the hearth plates 21, the entire inside of the furnace body 20 must be kept in a high temperature atmosphere at all times, and the combustion air 23 must be distributed evenly over the incinerated ash 3. However, if it is not possible to maintain the entire interior of the furnace body 20 in a high-temperature atmosphere at all times and to uniformly supply the combustion air 23 to the incinerated ash 3, combustion will not occur. During operation, a partial low-temperature area is generated inside the furnace main body 20, and as a result, the molten metal 5 that has been melted once solidifies, and the pusher 24'
We had to carry out compulsory discharge work due to
Furthermore, the incinerated ash 3 is not transferred evenly, and the incinerated ash 3 cannot be continuously melted inside the furnace body 20, making stable operation of the ash melting furnace 14 difficult.

[0011] In view of the above-mentioned circumstances, an object of the present invention is to provide a low-cost ash melting furnace that uses incinerated ash containing unburned carbon as a heat source and is capable of stable operation at low running costs. It is something.

0012

[Means for Solving the Problems] A container-shaped furnace body having a molten metal reservoir inside is provided, a supply port for incineration ash containing unburned carbon is formed in the upper part of the furnace body, and the molten metal in the furnace body is Ash melting characterized in that a discharge port for the molten metal obtained by melting the incinerated ash is formed in the storage part, a heat generating device is provided in the furnace body, and an oxygen supply nozzle for supplying air or oxygen is provided inside the furnace body. It is something that goes into the furnace.

[0013]

[Operation] First, as an initial start-up of the ash melting furnace, incinerated ash containing unburned carbon is supplied from the supply port into the furnace main body, and when electricity is applied as a heat generating device, for example, through a current-carrying electrode, the unburned carbon in the incinerated ash is Electric current flows through the incineration ash, and the electric resistance of the unburned carbon heats the incinerated ash, raising the temperature and melting it. Once the furnace body is filled with molten metal, new incinerated ash is supplied to the furnace body to bring the melting furnace into full operation. After that, the energization to the energizing electrode is stopped and air or oxygen is supplied from the oxygen supply nozzle to burn the unburned carbon in the incinerated ash and melt the incinerated ash, and the molten metal is stored in the molten metal storage section. After that, it is discharged from the outlet. The incinerated ash then supplied is directly supplied to a melting furnace filled with molten metal, where it comes into contact with air or oxygen in this high-temperature atmosphere and molten metal, and combusts.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, examples of the present invention in which current-carrying electrodes are used in a heat generating device will be described with reference to the drawings.

FIG. 1 shows one embodiment of the present invention.

Molten metal 26 with incinerated ash 25 melted inside
A furnace body 27 is provided in the form of a closed container made of refractory material and has a molten metal storage section 43 capable of storing a predetermined amount of molten metal. The lower end of a chute 30 into which incinerated ash 25 from an incinerator 29 can be dropped is connected to the supply port 28 .

A discharge port 33 is formed in the lower part of the furnace body 27, and a weir plate is provided at the discharge port 33 for discharging the molten metal 26 exceeding the maximum liquid level 34 in the molten metal storage section 43 to an external solidification device (not shown). Overflow device 3 with 35
Connect 6.

For example, a plurality of current-carrying electrodes 37 are inserted into the furnace body 27 as a heat generating device from above so that their lower ends are below the maximum liquid level 34, and the furnace body 27
A current-carrying electrode 38, which is paired with the current-carrying electrode 37, is inserted and arranged to face the current-carrying electrode 37 from below.
8 are connected to a power source (not shown) so that they have different polarities.

The current-carrying electrode 37 is not necessarily placed vertically, but may be placed horizontally from the side wall of the furnace body 27.

The maximum liquid level 3 on the side surface of the furnace body 27
Oxygen supply nozzles 40 for injecting high-temperature air or oxygen 39 are provided at appropriate intervals at positions lower than the furnace body 27, and an exhaust port 42 for exhausting exhaust gas 41 generated inside the furnace body 27 is provided in the upper part of the furnace body 27. . A heat exchanger 45 is provided to exchange heat between the exhaust gas 41 and the air or oxygen 39 supplied to the oxygen supply nozzle 40.

Next, the operation will be explained.

Incineration ash 25 containing a required proportion of unburned carbon, which is generated by incinerating waste such as municipal garbage while controlling the degree of combustion in the incinerator 29, is discharged from the incinerator 29 into a chute 30. . Then, the incinerated ash 25 is supplied from the chute 30 to the furnace body 27.

Next, the current-carrying electrode 3 is connected to a power supply (not shown).
Incineration ash 25 containing conductive unburned carbon via 7, 38
By passing a current through the incinerated ash 25, the incinerated ash 25 is heated by the electrical resistance value of the incinerated ash 25 (electrical resistance heating), and furthermore, high temperature air or oxygen is supplied from the oxygen supply nozzle 40.
By spewing out into the incineration ash 25 of the furnace body 27,
The incinerated ash 25 is melted by combustion heat generated by burning unburned carbon contained in the heated incinerated ash 25, and the furnace main body 27 is initially activated. In addition, in the initial startup of the furnace body 27, instead of the incineration ash 25,
It is also possible to charge fuel such as coke or conductive metal scrap into the furnace body 27, or to charge a mixture thereof.

Once the furnace body 27 has been started, the electrical resistance heating of the incinerated ash 25 by energization of the energizing electrodes 37 and 38 is stopped, and the amount of air or oxygen 39 supplied is adjusted to remove unburned carbon. Control so that combustion is sustained.

As a result, the incineration ash 25 continues to be melted using the combustion heat of unburned carbon as a heat source, making it possible to operate at low running costs. At this time, the generated combustion gas 41 is discharged to the outside from the exhaust port 42.

The molten metal 26 generated by melting the incinerated ash 25 is stored in the molten metal storage section 43 of the furnace body 27, and the molten metal 26 is stored in the molten metal storage section 43 until the maximum liquid level 34 is reached. Ru. Molten metal 2 in molten metal storage section 43
6 reaches the maximum liquid level 34, the molten metal 26 that exceeds the maximum liquid level 34 flows from the outlet 33 of the furnace body 27 to the overflow device 36, and from the overflow device 36 to an external solidification device (not shown). is discharged to.

In this way, the molten metal reservoir 43 is provided in the furnace body 27.
Since the molten metal 26 is retained in the molten metal storage part 43 for a predetermined time by providing a Therefore, only the completely melted molten metal 26 in the lower part of the molten metal storage part 43 is continuously discharged to the outside from the discharge port 33 via the overflow device 36, and the incompletely melted molten metal in the upper part of the molten metal storage part 43 is continuously discharged to the outside. 26 is prevented from being discharged.

In addition, when controlling the temperature of the molten metal 26 inside, the molten metal 2
6 (molten slag, such as the molten metal 26 of the incinerated ash 25, has been confirmed to be electrically conductive, and has already been used in various applications). The molten metal 26 generates heat depending on the electrical resistance value of the molten metal 26, and the temperature of the molten metal 26 is controlled thereby.

[0029] The present invention is not limited only to the above-mentioned embodiments, and it is possible to melt even incinerated ash 25 that does not contain unburned carbon if necessary (this (air or oxygen is not required), equipment such as electric arc, induction heating, oil or gas burner can be used as a heat generating device, and an adjustment gate is provided in the middle of the chute to adjust the amount of incinerated ash supplied. Of course, various modifications may be made without departing from the spirit of the present invention.

[0030]

As explained above, according to the ash melting furnace of the present invention, incineration ash containing unburned carbon is charged into the molten metal storage section of the furnace body from above, and air or oxygen is supplied to the molten metal storage section. It is possible to continue melting of the incinerated ash that has been input by burning the unburned carbon and using the combustion heat as a heat source, and it has the excellent effect of enabling stable operation with a simple structure and low running cost. .

[Brief explanation of the drawing]

FIG. 1 is an overall side sectional view of an embodiment of the invention.

FIG. 2 is a schematic side sectional view of a conventional example that utilizes arc and electrical resistance heat.

FIG. 3 is a schematic side sectional view of a conventional example using a burner.

FIG. 4 is an overall schematic side view of a conventional example using incineration ash containing unburned carbon.

FIG. 5 is a side sectional view of another conventional example using an incinerator bed containing unburned carbon.

[Explanation of symbols]

25 Incineration ash 26 Molten metal 27 Furnace body 28 Supply port 33 Discharge port 37, 38 Current-carrying electrode 39 as a heat generating device
Air or oxygen 40 Oxygen supply nozzle 43 Molten metal reservoir

Claims (1)

[Claims] 1. A container-shaped furnace body with a molten metal reservoir inside is provided, a supply port for incineration ash containing unburned carbon is formed in the upper part of the furnace body, and the molten metal reservoir of the furnace body is provided with An ash melting furnace characterized by forming an outlet for molten metal obtained by melting incinerated ash, providing a heat generating device in the furnace main body, and providing an oxygen supply nozzle for supplying air or oxygen into the furnace main body.