JPH0372889B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an incineration residue processing device for melting incineration residue discharged from an incinerator. The present invention relates to an incineration residue processing device that can prevent solidification of adhesion to walls and the like.

Generally, municipal garbage and industrial waste are incinerated, but the incineration residue is usually disposed of in a landfill.

Incidentally, this landfill disposal poses larger social problems than issues such as securing a landfill site and measures for inundation activation.

Therefore, recently, a method of melting and solidifying incineration residue has been developed which solves these problems all at once and makes it non-polluting.

This processing method will be explained based on Fig. 1.
Reference numeral 1 denotes an incinerator such as a stoker type furnace or a rotary kiln type furnace, in which waste M such as municipal garbage is incinerated by combustion air 2 introduced therein.

The discharged incineration residue N is introduced into the melting furnace 4 of the incineration residue treatment device 3, and the unburned carbon remaining therein is combusted by the combustion air 5 supplied at the inlet of the melting furnace, and the combustion heat is used to burn it. Heat and melt the ash. The molten slag 6 flows diagonally downward through the hearth 7 and forms a predetermined-shaped lump from the discharge end 8 and falls into a slag cooling water tank 9 located below, where it is cooled and solidified into lump-like solids. is generated.

By the way, in this type of conventional example, since the combustion air 5 is supplied at the inlet of the melting furnace to burn unburned carbon, a sufficient amount of heat is not supplied to the molten slag 6 flowing through the hearth 7. There was a problem that Zuko's slag adhered to the hearth 7 and solidified, clogging the inside of the furnace.
Moreover, this phenomenon occurs not only on the hearth 7 but also on the furnace walls, and not only does the operation have to be interrupted to remove the adhered and solidified slag, but it also takes a lot of time to remove it because it is firmly adhered. , had to require effort.

For this reason, oxygen has been supplied instead of air in order to increase the combustion temperature and prevent the solidification of molten slag, but in this case, the power consumption of the oxygen generator is large and the handling is difficult. It wasn't easy.

On the other hand, in addition to the above conventional example, on the surface of the incineration residue,
It is also possible to directly irradiate flame from an oil burner to melt the incineration residue or molten slag, or insert an electrode into the incineration residue or molten slag and melt it using Joule heat. Since the molten high-temperature part of the barrel is exposed, there is a large heat loss due to radiant heat, and furthermore, since the thermal conductivity of the molten slag is poor, the amount of oil consumed inevitably increases, leading to an increase in running costs. In addition, the method using Joule heat cannot use unburned carbon in the residue as fuel, resulting in increased power consumption and is not suitable for practical use.

The present invention has focused on the above-mentioned problems and has been devised to effectively solve the problems.

The object of the present invention is to provide a melting furnace having an inclined hearth in which the discharged incineration residue flows down under its own weight to form a moving layer, and a combustion layer in the moving layer of incineration residue formed by the hearth. A combustion air supply means for supplying air to burn unburned carbon, and a heating means provided on the back side of the hearth for heating the hearth, so that the inside of the layer is kept warm by the residue layer. It is an object of the present invention to provide an incineration residue processing device which can greatly reduce fuel costs by burning and melting the slag, and which can be operated continuously by preventing the molten slag from adhering to the hearth and solidifying.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, FIG. 2 is a longitudinal sectional view showing a first embodiment of the processing apparatus according to the present invention.

As shown in the figure, the incineration residue processing apparatus includes a melting furnace 10 that burns and melts unburned carbon in incineration residue N discharged from the incinerator, and a moving layer 11 of incineration residue N transferred into the melting furnace 10. It mainly consists of a combustion air supply means 12 that supplies combustion air therein, and a heating means 13 that heats the moving bed 11.

The melting furnace 10 is formed as a substantially cylindrical casing 14 whose outer shell is made of refractory bricks, etc., and one end of the upper part thereof is expanded upward to be connected to the residue discharge port of the incinerator 1. A hopper or incineration residue inlet 15 is formed (see FIG. 1). This melting furnace 10 is tilted downward at a predetermined angle along the direction of transport of incineration residue or molten slag transferred therein, and these moving layers 1
1 can flow down under its own weight.

A molten slag discharge passage 16 extending vertically is connected to the other end of the lower part of the casing 14 to discharge the generated molten slag, and the molten slag that falls in the form of a lump is connected to the lower end of this passage. Slag cooling water tank 9 for cooling and solidifying the molten slag
(See Figure 1).

In the middle of the exhaust passage 16, there is provided a flue 17 which is branched from this and inclined slightly upward, and the combustion exhaust gas is sucked by a blower 18 and cooled by an exhaust gas cooler 19, and then released into the atmosphere. It is designed to be emitted to

As shown in the enlarged view of FIG. 3, a large number of grate plates 20 are provided at the bottom of the melting furnace 10 constructed in this way along the inclination direction or the direction of transport of the residue. This grate board 20 is made of fire-resistant ceramics formed into a rectangular shape, and the ends of the grate boards that are adjacent to each other in the inclination direction are overlapped vertically with a predetermined gap between them to form the entire grate board 20. The hearth 21 is formed as a whole.

On the lower surface (back side) of the lower end of this grate board 20,
A support member 22 for maintaining the gap by contacting the upper surface of the upper end portion of the grate board 20 adjacent to the inclination direction.
is provided.

Both ends of these grate plates 20 are supported by the side walls of the furnace so that the angle of inclination thereof can be varied, so that the velocity of the moving layer of incineration residue can be investigated.

On the back side of each of these grate plates 20, a heating means 13, which is a feature of the present invention, is provided along the longitudinal direction.
is provided. This heating means is a heating element 23
and a heating element protection case 24 that covers this. The heating element 23 is made of, for example, silicon carbide molded into a rod shape, since a high temperature is required to prevent solidification of the molten slag. An unobtainable high temperature was obtained, and the grate plate 2
By heating the moving layer 11 or the molten slag transferred above the molten slag, it is possible to prevent it from solidifying. This heating element 23 is not limited to one made of the above silicon carbide as long as it can generate a high temperature higher than the melting point of the molten slag. Also,
It goes without saying that the grate plate 20 is also made of a member (ceramics, etc.) having a temperature higher than the melting temperature of the slag.

Each heating element 23 is spaced apart from this by a predetermined interval by the heating element protective case 24 having a semicircular cross section.
The upper end of the protective case 24 is attached to the lower surface of the grate plate 20 and is integrally fixed thereto. In order to prevent the heating element 23 from deteriorating, the heating element protective case 24
It is preferable to have a closed space inside and fill it with an inert gas such as nitrogen.

A plurality of partition walls 26 are provided on the upper side surface 25a of the furnace bottom plate 25, and extend obliquely upward toward the respective protective cases 24, and whose upper ends slide into contact with the outer surfaces of the protective cases 24. The air box 27 is constructed by dividing the lower space of the grate board 20 into a large number of sections in the longitudinal direction.

Inside each of these wind boxes 27 is a combustion air supply pipe 30 with an on-off valve 28 and an orifice 29 interposed in the middle.
is inserted through the furnace bottom plate 25, and the air supply pipe 30 and the wind box 27 constitute the combustion air supply means 12. In other words, this wind box 2
The heated combustion air introduced into the movable bed 7 is supplied into the moving bed from a gap formed in the overlapping portion of the grate plate 20, that is, a combustion air injection port 31.

In the above embodiment, since the inclination angle of the grate board 20 is variable, in order to make the protective case 24 slidable relative to the partition wall 26, the outer surface and the upper end of the partition wall 26 are connected to each other. However, if the angle of inclination of the grate board 20 is fixed, the partition wall 26 and the protective case 24 may be connected and fixed to increase their strength.

The operation of the present invention configured as above will be described.

First, as shown in Figures 1 and 2, industrial waste M such as municipal waste is fed into the incinerator 1 from the input port, and after being burned normally therein, the generated incineration residue is transferred to the incinerator. It is supplied into the incineration residue inlet 15 of the melting furnace 4 which is connected to the end of the incineration residue. During combustion, the unburned carbon in the residue is preferably 7 to 25%.
Combustion in the furnace is controlled so that the remaining amount remains within 20%. Specifically, combustion control is performed by adjusting the input amount of waste, the amount of combustion air, the stoker feed speed in the case of a stoker type, and the rotation speed in the case of a rotary kiln type.

As shown in FIGS. 2 and 3, the incineration residue N containing unburned carbon is stacked on the bottom plate 20 in the melting furnace 10, and flows down in the inclined direction on top of this as a moving layer 11.

On the other hand, the wind box 27 is connected via the combustion air supply pipe 30.
The high-temperature combustion air supplied into the interior is supplied to the combustion air injection port 31 formed in the overlapping part of the grate plate 20.
The unburned carbon is then fed into the moving bed, whereupon the unburnt carbon is combusted and the incinerated ash is melted by the heat generated at this time. In this way, since air is supplied from the bottom of the residue in parallel and directly into the moving bed, it is possible to burn the residue from within, and there is also little heat radiation, and the combustion heat is retained within the bed, making it effective for melting. can contribute. This molten slag flows under its own weight over the grate plate 20 which is heated to a high temperature by the heating element 23, that is, above the melting point of the molten slag, and from the lower discharge end becomes molten slag of a predetermined size and is turned into a molten slag discharge passage 16. The slag is cooled and solidified in the slag cooling water tank 9. Then, the combustion exhaust gas is sent to the blower 1 in the same direction as the molten slag flows out.
8 and is discharged from the flue 17 while preventing cooling of the discharge end of the grate board. In this way, even after the unburnt carbon has burned out, the molten slag remains
Since it is maintained in a molten state by constantly being supplied with heat from the grate plate 20 heated above its melting point, it flows down the hearth 21 without adhering to and solidifying on the hearth 21 or the furnace wall. Furthermore, even if the molten slag adheres to the hearth 21 and solidifies, since the hearth 21 is heated, the viscosity of the adhered portion becomes low and becomes slippery, and eventually it flows down the inclined hearth 21. . In this way, the molten slag flows down the hearth 21 without adhering to and solidifying on the hearth 21 etc.
Blockage in the furnace 10 due to adhesion and solidification is prevented,
Stable operation can be performed.

Furthermore, since the incineration residue can be heated with heat other than combustion heat, this combustion is promoted, and it is possible to cope with low-load operation or when there is little unburned carbon in the residue.

Furthermore, since the unburned carbon is burned directly above the grate plate 20, the grate plate 20 is heated even better, the molten slag flows better, and the separation between the unmelted ash and the molten slag is facilitated. This improves the contact between unburned carbon and combustion air.

Furthermore, in order to change the flow rate of the incineration residue or molten slag, this is done by increasing or decreasing the inclination angle of each grate board 20.

In the above embodiment, heating is performed from the lower part of the grate plate with the heating element 23, but the present invention is not limited to this. For example, heating with the heating element may be performed through the side or upper furnace wall. Alternatively, the heating element may be arranged in the furnace alone or inserted into a protective case.

In addition, when supplying combustion air, a method of blowing out from the combustion air injection ports 31 formed between the grate plates was adopted, but the method is not limited to this, and for example, a method of blowing from a nozzle from the side of the furnace (side nozzle method) Alternatively, this side nozzle method and the method according to this embodiment may be used in combination, and the combination is made in consideration of thermal efficiency and combustion efficiency.

Next, a second embodiment will be described based on FIG.

The purpose of this second embodiment is to supply combustion air only to the high-temperature part where unburned carbon in the incineration residue burns, and to insulate this high-temperature part with an ash layer or a residue layer to reduce heat loss. This is what I did.

The same parts as those in the first embodiment are given the same reference numerals and the description thereof will be omitted.

In this embodiment, in order to simplify the structure,
The hearth 33 is constructed by integrally forming the ceramic grate plate 32 continuously without dividing it, and slanting it toward the flow direction of the incineration residue N.

A heating means 34 is continuously formed on the back surface of the hearth 33 along its longitudinal direction. This heating means 34 is composed of a heating element 23 made of silicon carbide and a heating element protection case 24 formed to cover the heating element 23, as in the first embodiment.

A plurality of injection nozzles 36 are installed along the flow direction of the incineration residue N on the furnace side wall that partitions the combustion section (upper part of the furnace) 35 that mainly burns unburned carbon, and each of these injection nozzles 36 A combustion air supply pipe 30 having an on-off valve 28 and an orifice 29 interposed therebetween is connected to the combustion air supply pipe 30, and a combustion air supply means 37 is constituted as a whole. Therefore,
High-temperature combustion air is supplied directly from the injection nozzle 36 into the moving bed of incineration residue.

The operation of this embodiment is almost the same as that of the first embodiment, but in particular, in the high temperature section 35, high temperature combustion is directly injected into the moving bed 11 from the injection nozzle 36 provided on the side wall of the furnace in the horizontal direction. By supplying air, it is possible to form molten slag by burning from inside the ash layer while keeping it warm.

Therefore, since radiant heat is reduced, heat loss can be reduced and thermal efficiency can be significantly improved.

Further, as in the first embodiment, since the molten slag flowing on the grate plate 32 is heated by the heating element 23 of the heating means 34, it can flow down smoothly without adhering to the furnace wall or the like and solidifying.

Although it is thermally desirable that the present incineration residue processing device be installed in series with the incinerator, it may be installed independently.

In summary, the present invention exhibits the following excellent effects.

(1) Since it is possible to prevent molten slag from adhering and solidifying to the hearth and furnace walls, clogging problems can be eliminated and stable operation can be achieved.

(2) Even if the molten slag adheres and solidifies, the hearth and furnace walls remain at a high temperature, so the viscosity of the adhered parts is low and slippery.
Can be easily discharged.

(3) Since combustion and melting are performed inside the ash layer while keeping the heat in the ash layer, there is no heat radiation or loss to the outside, and the thermal combustion efficiency can be improved as much as possible.

(4) Therefore, the amount of auxiliary fuel used can be reduced, and air can be used as the combustion gas instead of oxygen.

(5) Also, since there is no need to use oxygen,
Electric power costs for oxygen generation can be eliminated, and all equipment necessary for this can be eliminated.

[Brief explanation of drawings]

Fig. 1 is a vertical cross-sectional view showing a conventional incineration residue processing device connected to an incinerator, Fig. 2 is a longitudinal cross-sectional view showing a first embodiment of the present invention, and Fig. 3 is an enlarged view of the main parts of the present invention. The perspective view and FIG. 4 are longitudinal sectional views showing a second embodiment of the present invention. In the figure, 1 is an incinerator, 10 is a melting furnace, 11 is a moving bed, 12 and 37 are combustion air supply means, 1
3 and 34 are heating means, 21 and 33 are hearths, and N is incineration residue.

Claims (1)

[Claims] 1. In an incineration residue treatment device that burns the unburned carbon contained in the incineration residue discharged from an incinerator and obtains it as molten slag, the above-mentioned incineration residue discharged flows down under its own weight to form a moving layer. a melting furnace having a sloping hearth; a combustion air supply means for supplying combustion air into a moving layer of incineration residue formed by the hearth to burn unburned carbon; What is claimed is: 1. An incineration residue processing device, comprising a heating means for heating a hearth.