JPH10274407A - Induced heating type incinerated ash melting furnace and incinerated ash melting processing mehtod - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a molten slag from belting fixed with an emission opening in an induced heating type incinerated ash melting furnace. SOLUTION: Incinerated ashes are melted by heating a conductive heating element 10 laid out inside a furnace and a molten slag is discharged from a slag hole 7 provided projectingly into the furnace from the bottom of the furnace, thereby producing a molten slag sump between the slag hole and the furnace bottom. This construction makes it possible to prevent the temperature effect of the molten slag and prevent the temperature effect produced by contact with the open air when the slag is discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incineration ash melting furnace and an incineration ash melting method for reducing and solidifying incinerated ash generated by incineration of municipal solid waste, sewage sludge and other wastes. More particularly, the present invention relates to a technique for melting incinerated ash by electromagnetic induction heating.

[0002]

2. Description of the Related Art Until now, municipal solid waste has been disposed of as landfill, but since it causes secondary pollution, it has recently been disposed of after incineration. However, although the volume of garbage is reduced to 1/10 by incineration, shortage and difficulty in securing landfill, elution of harmful substances from landfill ash or environmental recontamination by unburned substances Therefore, further detoxification treatment is desired.

As a detoxification method, as set forth in the notification of the Ministry of Health and Welfare, a melt solidification method, a cement solidification method, a chemical kneading method,
The solvent elution method and the like are generally used, but each has its advantages and disadvantages, and at present it is undecided. Among them, a melting and solidifying method that melts incinerated ash, solidifies it into glass, and confines heavy metals has attracted attention. The method of incineration ash fusion and solidification is described in “Journal of the Japan Society of Waste Management”, Vol. 5, No. 1, pp. 46-59.
As described in (1994), a burner combustion heating system utilizing combustion heat, an arc discharge heating system, a plasma heating system,
There is an electromagnetic induction heating system and the like, and melting furnaces having various structures according to the heating system have been proposed.

[0004]

In the incineration ash melting treatment by the burner combustion heating method, a large amount of exhaust gas is generated due to the combustion of fuel and a combustion aid (for example, air), and the load of the exhaust gas treatment is increased. Accompany. In the arc discharge heating method, it is necessary to pool molten iron or the like in a furnace as a heat source for melting incineration ash, which is structurally complicated and causes severe electrode consumption.

Regarding the electromagnetic induction heating method, a method has been proposed in which molten iron or the like is pooled at the bottom of the furnace and then heated by induction heating to melt the incinerated ash. There is a problem that the degree cannot be obtained. In addition, a container in which a carbon material, for example, graphite is molded is disposed in a magnetic field of an induction coil and is melted by heat generation. However, the container is liable to be consumed and damaged. The contact surface with the incineration ash is also limited, and the device may be complicated, for example, by providing an auxiliary heating element to increase the contact area.

In any method, it is essential to devise a furnace structure in which the molten incinerated ash, ie, the molten slag, is taken out of the furnace without being fixed.

An object of the present invention is to achieve slag slag removal from a high-temperature region in an incineration ash melting furnace of an electromagnetic induction heating system, and to prevent the slag slag outlet from being blocked.

[0008]

The incineration ash melting furnace according to the present invention has a conductive heating element disposed in a furnace heated by electromagnetic induction, and is charged into the furnace by induction heating the conductive heating element. In the induction heating incineration ash melting furnace in which the incinerated ash was melted and the molten slag generated by melting the incinerated ash was discharged from the slag slag port at the bottom of the furnace, the slag slag port was positioned higher than the furnace bottom. The present invention is characterized in that it protrudes inside the furnace and forms a molten slag pool between the slag outlet and the furnace bottom.

In a preferred embodiment of the incineration ash melting furnace according to the present invention, conductive heating elements are stacked in the furnace, and an induction heating coil is provided on the furnace side wall along the stacking height, and electricity is supplied to the induction heating coil. The conductive heating element causes self-heating. The incineration ash is introduced into the furnace through the incineration ash inlet at the top of the furnace, and is heated by contact heating and melted.
When the conductive heating element is consumed and reduced, a new conductive heating element is additionally administered from the heating element loading port at the top of the furnace to maintain the molten state in the furnace.

[0010] The melted incinerated ash, ie, molten slag, flows down the surface of the conductive heating element and accumulates at the furnace bottom. The slag outlet protrudes into the furnace from the bottom of the furnace, and the molten slag accumulates by the amount of the protrusion. Then, the molten slag overflowing from the top of the slag outlet is discharged out of the furnace, dropped into a water tank or the like, cooled, and solidified as granulated slag or the like. A part of the high-temperature gas generated in the furnace is discharged from an exhaust port on the upper part of the furnace, and another part of the gas is discharged from a slag discharge port together with the molten slag.

By discharging a part of the high-temperature gas generated in the furnace and the molten slag together from the slag outlet, contact between the molten slag and the outside air can be avoided, and the temperature of the slag can be kept constant. become. In addition, it is possible to prevent the viscosity of the slag from increasing and secure a stable fluidity, thereby preventing the slag from sticking to the slag outlet. Further, invasion of outside air into the furnace can be suppressed.

The pedestal and the slag outlet provided on the furnace wall are preferably made of a carbon material, particularly graphite, so that the slag can be prevented from sticking to the slag outlet. In addition, by attaching a stopcock with an opening and closing function to the furnace bottom, it is possible to intermittently extract molten slag stagnating in the furnace bottom, and it is possible to adjust the amount of molten slag stagnating in the furnace become.

The conductive heating element used in the present invention is preferably made of a carbon material, particularly graphite or amorphous carbon. The main cause of the material consumption of these conductive heating elements is a reaction with oxygen. Thus, it is desirable to devise a furnace lid structure at the top of the furnace to prevent outside air from entering the furnace. Attachment of a sealing lid to the slag outlet is effective in providing an effect of preventing outside air from entering.

When the conductive heating element is consumed and reduced by the melting reaction of the incinerated ash, it is necessary to secure and maintain the heat capacity required for melting the incinerated ash by additionally administering a new conductive heating element. Become. A necessary heat capacity can be secured by providing a heating element loading port at the upper part of the furnace and supplying the heating element into the furnace.

In order to prevent outside air from entering the furnace when the heating element is supplied, it is preferable that the heating element carrying-in port is constituted by a charging chamber separated by a gate or the like. When the conductive heating element is additionally administered, the molten slag is preferably discharged into the furnace in view of the amount of molten slag discharged from the slag discharge port or the amount of ash that can be supplied from the ash input port at the top of the furnace.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 is a sectional view showing one embodiment of an induction heating type incineration ash melting furnace according to the present invention. This electromagnetic induction heating furnace has a furnace body 1, a furnace lid 2 for closing the upper part of the furnace body 1, an ash input port 4 on the upper part of the furnace body 4, a heating element carrying-in port 5, and an upper exhaust connected to the furnace lid 2. The furnace comprises a port 6, a slag tap 7 and a stopper 8, which penetrate the furnace wall under the furnace body 1 and protrude into the furnace, and an induction heating coil 9 wound around the furnace body. Heating element 10
Are stacked.

The conductive heating element 10 is a carbon material, particularly made of graphite or amorphous carbon, and is regularly or irregularly laminated in a columnar or spherical shape.

The furnace lid 2 is connected to the furnace body 1 to prevent outside air from entering the furnace and to seal the upper part. The furnace lid 3 is a part of the furnace lid 2 which can be opened and closed. Similarly, the furnace lid 3 has a sealed structure and is used for inspection and the like. For repairing the inside of the furnace, the furnace lid 2 may be removed.

The ash inlet 4 at the upper part of the furnace body 1 is connected to an ash supply device (not shown) to supply the incinerated ash by mechanically pushing it into the furnace. By adjusting the supply speed, the supply amount of incinerated ash can be changed. In the case of increasing the size of the melting furnace, a plurality of ash inlets may be provided to average the amount of supplied ash. The ash inlet 4 is connected to the furnace body 1, but may be connected to the furnace lid 2.

The heating element loading port 5 at the upper part of the furnace supplies the conductive heating element 10 into the furnace, and is mechanically operated by connecting a feeding device (not shown) to the heating element loading port 5. Can also. In FIG. 1, the conductive heating element 10 is
It is made to stand by in the charging chamber 50 divided by 1 and 52, and the gate 51 inside the furnace is opened and pushed in mechanically.
Accordingly, the work can be performed while being cut off from the outside, and the invasion of outside air into the furnace can be suppressed. In FIG. 1, the heating element carrying-in port 5 is provided on the furnace lid, but may be installed on the furnace body side.

The upper exhaust port 6 in the upper part of the furnace is for discharging gas generated in the furnace, and is connected to a gas processing facility (not shown) provided outside for detoxification. Then, a throttle mechanism (for example, a damper or the like, not shown) is provided in the exhaust system of the upper exhaust port 6, and the gas exhaust amount is adjusted by the throttle mechanism. The remaining in-furnace gas is discharged out of the furnace together with the molten slag from the slag outlet 7 at the lower part of the furnace.

Slag discharge port 7 arranged at the lower part of furnace body 1
Is to discharge the molten slag retained in the furnace to the outside of the furnace by overflow, and is disposed higher than the position where the stopper 8 is attached.

FIG. 2 is a partially cutaway cross-sectional view of the lower part of the furnace shown in FIG. 1 around the attachment of the slag outlet 7 and the stopper 8. The outer end of the slag outlet 7 is closed with a sealing lid 73. Indicates a state of failure. The shape of the slag discharge port 7 is such that the upper portion is narrower, the lower portion is wide open, the step or the lower portion is tapered, and the slag falls without adhering to the lower portion of the molten slag overflowing from the upper opening. By cutting the top groove 71 at the top of the slag outlet 7, the flow of the slag can be stabilized.

The slag outlet 7 is attached from the outside to a pedestal 72 embedded in a furnace body and fixed with a holding fastener (not shown). The slag outlet 7 and the pedestal 72 are desirably made of a carbon material having good releasability from molten slag, particularly graphite. Thereby, the attachment and detachment replacement of the slag outlet 7 is facilitated, and slag adhesion to the inner surface of the slag outlet 7 can be prevented.

FIGS. 1 and 2 show a case in which the slag can be detached from the outside of the furnace.
The slag outlet 7 can be inserted from inside the furnace by making the fitting portion of 2 into an inversely tapered shape. Further, a sealing lid 73 is provided at the outer end of the slag outlet 7 so as to be openable and closable, and the slag outlet 7 is closed during operation when there is no discharge of molten slag or high-temperature gas in the furnace at the time of starting and stopping, and the outside air is opened. Prevent intrusion.

The stopper 8 arranged at the lower part of the furnace is provided with an opening, and the stopper 8 is turned to discharge the molten slag remaining at the furnace bottom from the opening appropriately. For example, when the metal component in the incinerated ash is melted and the retained molten slag contains a large amount of metal material, it is appropriately extracted from the furnace bottom. Further, when the furnace is stopped, the molten slag at the bottom of the furnace can be withdrawn, and the heating element can be removed. At this time, it can be collected separately from the slag discharged from the slag outlet 7. The stopper 8 and the pedestal 81 are preferably made of a carbon material having good releasability from the molten slag, particularly graphite, and its fitting portion is preferably tapered to prevent leakage. The stopper 8 is installed below the slag discharge port 7. To be precise, it is lower than the top of the slag outlet 7 or the slag overflow position of the top groove 71 which protrudes into the furnace. Therefore, the molten slag can always be discharged out of the furnace starting from the top or the top groove 71 of the slag outlet 7.

If a release material (eg, graphite powder) or the like is applied to the slag outlet 7 and the pedestal 72 and between the stopper 8 and the pedestal 81, a detachable material (eg, graphite powder) or the like can be easily applied or detached. In addition, the shape and the covering structure of the portion that comes into contact with the outside air can be appropriately designed, and the durability of the carbon material can be increased. The operation of the sealing lid 73 and the stopper 8 may be designed to be remotely controlled.

FIGS. 1 and 2 show the mounting positional relationship between the slag outlet 7 and the stopper 8 when the bottom of the furnace body is flattened. It is also easy to arrange the spout 7 at a high position and the stopper 8 at a low position.

The purpose of the slag outlet 7 is to simultaneously discharge the molten slag and the generated gas in the furnace. In FIG. 1, the duct 61 is connected just below the slag outlet 7 and the duct 61 is connected.
Is provided with a lower exhaust port 60 in the middle. Lower exhaust port 60
Can be rendered harmless by introducing it to a gas processing facility (not shown) provided outside. The high-temperature gas generated in the furnace by melting the incineration ash is recovered from the upper exhaust port 6 and the lower exhaust port 60, and the high-temperature gas in the furnace can be adjusted from the slag discharge port 7 and discharged together with the molten slag. is there. The molten slag is cooled and solidified in a cooling water tank or the like (not shown) below the slag discharge port 7.

Next, an operation method for carrying out the present invention will be described with reference to examples. First, the starting process is performed by the induction heating coil 9.
When the current is supplied to the furnace, the conductive heating element 10 is heated to increase the temperature in the furnace. Then, the incineration ash is injected into the furnace to start melting the incineration ash. The molten slag drops between the layers of the heating elements and accumulates at the bottom of the furnace, overflows from the slag outlet 7, and is discharged out of the furnace together with the hot gas in the furnace.

Immediately before the slag discharging, the sealing lid 73 of the slag discharging port 7 may be opened. Since the high-temperature gas from the slag outlet 7 generates gas due to the presence of incineration ash in the furnace, the slag outlet 7 is discharged even in a state where the molten slag does not overflow, so that the operation can be performed without invasion of outside air.

This temperature operation is desirably maintained at a temperature equal to or higher than the melting point of the incinerated ash, and is preferably about 1300 to 1600 ° C.
Thus, in the process of melting incineration ash, slag slag can be stably and continuously achieved from the slag slag port 7 protruding into the high-temperature region, but the metal component in the incineration ash is melted and stagnates at the furnace bottom. Come. In this case, the stopper 8 is opened and closed to discharge intermittently slag. Further, in the step of melting the incineration ash, when the conductive heating element 10 stacked in the furnace is exhausted, the conductive heating element 10 is newly introduced from the heating element carrying-in port 5.

FIG. 3 shows a test result when the incinerated ash is melted by the electromagnetic induction heating type incinerated ash melting furnace of the present invention having an output of 35 kW. The horizontal axis is the heating element filling amount in the furnace, and the predetermined heating element charging amount is set to 1. The vertical axis indicates the amount of slag discharged from the slag discharge port, and the prescribed heating element charging amount
The slag discharge amount with respect to (heating element filling amount 1.0) is shown as 1.

It is apparent from FIG. 3 that the amount of discharged slag decreases due to a decrease in the filling amount of the heating element, that is, the consumption of the heating element, and the amount of slag discharged increases due to an increase in the filling amount of the heating element, that is, administration of the heating element. Therefore, by knowing the change in the amount of slag discharged from the slag outlet, the heating element carrying-in port 5 is operated, and the molten state in the furnace can be stably maintained. Further, since the amount of slag discharged is balanced with the amount of incinerated ash supplied from the ash inlet 4, the slag discharge amount is measured by an ash supply device connected to the ash inlet 4, and the change in the amount of incinerated ash supplied causes the heating element carrying-in port 5 to change. May be activated.

When the furnace is stopped, the supply of incinerated ash is stopped, the molten slag in the furnace is discharged by opening and closing the stopper 8 and the sealing lid 73 of the slag discharge port 7 is closed to remove the furnace body without invasion of outside air. Cooling. From the above, it is possible to provide not only a furnace structure that can prevent the heating element from being consumed and achieve stable continuous slagging, but also operate the ash supply unit, the heating element loading unit, the slag slagging unit, and the like by remote control. We can provide a method. Further, according to the present invention, since no fuel or the like is used, only a small amount of gas generated from unburned components in the incinerated ash can be used, and a melting furnace with a small amount of exhaust gas can be provided.

[0036]

According to the induction heating incineration ash melting furnace and the incineration ash melting method of the present invention, the following effects can be obtained.

(1) By making the slag outlet higher than the furnace bottom, the molten slag stays at the furnace bottom and the heat capacity increases, so that the temperature drop of the molten slag can be prevented. In addition, since the high-temperature gas generated in the furnace is discharged at the same time as the molten slag, it is possible to prevent the outside air from contacting at the time of slag slag, thereby preventing the slag temperature from lowering.

(2) By inductively heating the heating elements stacked in the furnace, the incineration ash can be easily melted.
Even if the heating element is exhausted, the amount of heat of melting of the incineration ash can be secured by newly adding it. In addition, it is possible to suppress the invasion of outside air into the furnace and reduce the consumption of the heating element.

(3) It is possible to prevent the slag from sticking at the slag discharge port, to achieve stable and continuous discharge of the slag, to facilitate the replacement thereof, and to improve the workability and usability.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an induction heating type incineration ash melting furnace according to the present invention.

FIG. 2 is a partially cutaway cross-sectional view of FIG. 1 and is a cross-sectional view of a lower part of a furnace body.

FIG. 3 is a relationship diagram between a heating element filling amount and a slag discharge amount.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Furnace body, 2, 3 ... Furnace lid, 4 ... Ash inlet, 5 ... Heating element carry-in port, 6 ... Upper exhaust port, 7 ... Slag discharge port, 8 ... Stopper,
9 Induction heating coil, 10 Conductive heating element, 50 Input chamber, 51, 52 Gate, 60 Lower exhaust port, 61 Duct, 71 Top groove, 73 Sealed lid, 72, 81 Base.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F27D 11/06 F27D 11/06 A (72) Inventor Toshiaki Arato 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Hitachi, Ltd. Inside the Hitachi Research Laboratory, Ltd. Inside Hitachi Research Laboratory, Hitachi, Ltd.

Claims (4)

[Claims] 1. A conductive heating element is arranged in a furnace heated by electromagnetic induction, and the conductive heating element is heated by induction to melt the incineration ash charged into the furnace, thereby melting the incineration ash. In the induction heating type incineration ash melting furnace in which the molten slag generated by the slag is discharged from the slag discharge port at the bottom of the furnace, the slag discharge port is protruded into the furnace from the furnace bottom, and the slag discharge port is connected to the furnace. An induction heating type incineration ash melting furnace, wherein a molten slag pool is formed between the bottom and the bottom. 2. The induction heating incineration ash melting furnace according to claim 1, wherein the slag discharge port is formed of a carbon material. 3. The induction heating incineration ash melting furnace according to claim 1, further comprising an opening for discharging molten slag on the bottom of the furnace and a stopper for opening and closing the opening, and the opening is connected to the slag discharge port. An induction heating incineration ash melting furnace, which is provided at a lower position than the above. 4. A conductive heating element is disposed in a furnace of an electromagnetic induction heating type, and the incinerated ash charged into the furnace is melted by induction heating of the conductive heating element. In the incineration ash melting method in which the generated molten slag is discharged from a slag outlet at the bottom of the furnace, the molten slag is retained at the bottom of the furnace by projecting the slag outlet from the bottom of the furnace into the furnace. A method for melting incineration ash, wherein molten slag overflowing from a slag port is discharged outside the furnace.