JPH0926124A - Melting treatment method of refuse incineration ash and melting treatment installation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an installation which is high in thermal efficiency, small in power consumption, simple in structure and seldom to cause breakdown, and to make the best use of high carolific value waste matter, and generate molten slag having stabilized properties. SOLUTION: An ordinary refuse incinerator 1 which specifically burns ordinal refuse from which high temperature carolific value waste matter is separately removed is combined with a high temperature incinerator 4 which exclusively burns high carolific value waste. A high temperature furnace exhaust gas 62 in an imperfect combustion state discharged from the high temperature incinerator 4 is secondarily burnt in a secondary combustion chamber 46 located above a melting device 3 to produce a melting device gas 63. By using the radiation heat of this melting device gas 63, incinerated ashes 81 discharged from the ordinal refuse incinerator 1 and the high temperature incinerator 4 are processed by melting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a melting treatment method and a melting treatment facility for refuse incineration ash discharged from a refuse incineration facility for incinerating general waste or industrial waste.

[0002]

2. Description of the Related Art According to the revised Waste Management Law of October 1992, the fly ash collected in the dust collection facility of a refuse incineration facility contains heavy metals, which causes melting, cement solidification, and chemical treatment. It was specified that the stabilization treatment should be performed by any one of the four methods of treatment and acid extraction.

Therefore, a method of melting and solidifying the incinerated ash together with the fly ash has been in the limelight for the purpose of encapsulating the heavy metals contained therein as well as reducing the volume of the incinerated ash discharged.

At present, as the types of ash melting furnaces which are practically used, according to the position related to the incinerator, there are a direct connection type directly connected to the incinerator ash discharge port and a wet ash discharged from the incinerator. There is a separate type that temporarily stores the ash in an ash hopper, etc., and then treats it according to the heat source, such as surface melting furnace using burner (internal melting type) and plasma furnace, arc furnace, electric resistance furnace, etc. Can be roughly divided into the following methods.

A direct-connection type surface melting furnace whose schematic structure is shown in FIG. 6 and a separate type plasma melting furnace whose schematic structure is shown in FIG. 7 will be described below as typical examples.

In the direct-coupling type surface melting furnace shown in FIG. 6, the normal dust b1 introduced from the hopper a is dried in the rotary kiln c by the combustion air d1 heated by the combustion air preheater (not shown). The exhaust gas e1 that is burned and generated rises to the re-combustion chamber f, and the incineration residue b2 containing incombustibles such as metals is sent over the post-combustion grate g, while remaining unburned due to the combustion air d1. Things are even more dry
It is burned to form incineration ash h and falls into the melting device M.

Although post-combusted on the post-combustion grate g, combustible substances containing about 12 to 15% of free carbon still remain in the above-mentioned combustion ash h.
60%), and this combustible component becomes an internal heat source during melting.

The incineration ash h deposited on the hearth M1 made of a refractory material such as ceramics is pushed forward little by little by the pusher M2, and is advanced to the burner M3 installed on the ceiling.
And the high-temperature melting combustion air d2 that is pressure-fed from the lower part of the hearth described below, the above-mentioned residual combustible component starts igniting and burning, and is heated to 1200 to 1500 ° C. and melted from the surface.

The melted molten slag S1 is dropped from the drop pipe M4 into the water-sealed conveyor j, rapidly crushed and crushed to form a water-crushed slag S2, which is carried out to the outside (not shown).

Here, the high temperature exhaust gas e2 generated in the melting apparatus M is sucked from the drop pipe M4 by the exhaust gas fan k1 and heat-exchanged in the high temperature air heater k3 equipped with the melting furnace blower k2 to obtain the room temperature. After being mixed with the air d3 and further cooled, it is discharged into the reburn chamber f through the exhaust gas fan k1.

Further, the above-mentioned melting combustion air d2 is obtained by sucking the combustion air d1 by the melting furnace blower k2 and raising the temperature to about 500 ° C. by the high temperature air heater k3.

Next, in the separate type plasma melting furnace shown in FIG. 7, the melting device M is surrounded by a water cooling jacket M5, and a refractory melting tank M6 equipped with a plasma device P to be described later and a slag outlet M7. And an ash supply port M8 and a drop pipe M4 similar to FIG.

Further, the plasma device P shows an example of a transfer system, and the main plasma torch P1 (+
Electrode), lower electrode P2 (-electrode), cooling water pipes P3 (+ charged), P4 (-charged) and plasma gas supply port P5, and an ignition device, torch moving device, etc. not shown, and each electrode is a power supply device q. It is connected to the.

First, the incineration ash h which retains the water stored in the ash hopper n1 after pretreatment such as magnetic separation and pulverization is passed through the ash supply port n8 by the ash supply feeder n2 and then melted into the melting tank M.
6. Here, fly ash collected by a dust collector for a main flue not shown may be mixed in the incinerated ash h.

Next, while cooling the outer periphery of the plasma torch P1 with cooling water, an inert gas is supplied from the plasma gas supply port P5, and a DC voltage is applied between the plasma torch P1 and the lower electrode P2. Plasma that reaches 10,000 ° C. or higher is generated to melt the incineration ash h in the melting tank M6.

The molten molten slag S1 is formed by notching a part of the melting tank M6, dropping it from a slag outlet M7 inclined to the side of the drop pipe M4, and rapidly cooling it by cooling air d3 at room temperature which is jetted from the middle of the drop pipe. As a result, it is crushed and cooled in the slag conveyor r located below the drop pipe M4 to become air-cooled slag S3, which is carried out to the outside (not shown). Here, there is also a system in which the cooling system of the molten slag S1 is a water injection system as shown in FIG.

Further, the high temperature exhaust gas e2 generated in the melting apparatus M is sucked from the drop pipe M4 by an exhaust gas fan (not shown) and discharged into the atmosphere through a gas cooling device (not shown) and a melting furnace gas dust collector. To be done.

[0018]

As described above, the direct connection type surface melting furnace melts the high temperature incinerator ash discharged from the incinerator as it is due to the combustion heat of the combustible components remaining in the incinerator ash and the heating of the burner. It is a method to do.

Therefore, although there is an advantage that the thermal efficiency is high and the incombustibles can be melted collectively, the characteristics of the molten slag become unstable because the amount of the remaining combustibles is not constant and a stable high temperature is difficult to obtain. In addition to increasing fuel cost, high temperature combustion air for melting is required, and high temperature corrosion of the high temperature air heater is unavoidable. Furthermore, not only is the entire refuse incineration facility stopped when a melting device fails,
Until the restoration, the incineration ash cannot be expected to be completely burned, and there is a risk of pollution, so there was a problem that emergency measures such as a preliminary melting device were necessary.

On the other hand, the separate plasma melting furnace is
This is a method in which the iron content in the wet ash discharged from the incinerator is removed, the crushed fine ash is once stored in an ash hopper, etc., and then melted by the plasma heat of a separate melting furnace.

Therefore, the operability of adjusting the plasma output and the like is good and a stable high temperature is obtained, so that the characteristics of the molten slag are improved, but on the other hand, in addition to consuming a large amount of power for the wet ash drying and melting, Since the construction cost is high, it is not suitable for a facility that does not have a waste power generation facility, and there is a problem that not only a pretreatment device but also a treatment device for removed iron and exhaust gas is separately required.

[0022]

According to a first aspect of the present invention, there is provided a method for melting refuse incineration ash by melting, wherein an ordinary refuse incinerator in which waste having a high calorific value is separated and removed and a waste having a high calorific value is exclusively burned. A high-temperature incinerator is also installed, and the radiant heat of the high-temperature gas generated in the high-temperature incinerator is used to melt and process the incineration ash normally discharged from the refuse incinerator and the high-temperature incinerator.

In the method for melting refuse incinerated ash according to claim 2 of the present invention, the gas body is treated with oxygen or 2 for secondary combustion.
The temperature is maintained within a predetermined range by controlling the amount of secondary air.

The facility for melting waste incinerated ash according to claim 3 of the present invention comprises a normal waste incinerator in which waste having a high calorific value is separated and removed, and a high temperature incinerator for exclusively burning a waste in a high calorific value. The waste incineration ash melting treatment facility is provided side by side with a melting device provided downstream of the normal waste incinerator, and a secondary combustion chamber of the high temperature incinerator provided above the melting device.

According to a fourth aspect of the present invention, in the refuse incineration ash melting treatment facility, in the waste incineration ash melting treatment facility in claim 3, the incinerator ash discharged from the high temperature incinerator is in the normal waste incinerator. The carrying-out means for carrying in is provided.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an outline of a refuse incineration ash melting treatment facility according to the present invention, and FIG. 2 is an enlarged sectional view showing an outline of the vicinity of a melting apparatus.

In FIGS. 1 and 2, reference numeral 1 is a normal refuse incinerator, and an incinerator main body 11 having a normal furnace construction structure.
And a dust introduction hopper 12, a dry grate 13, a combustion grate 14, a post-combustion grate 15, a lower hopper group 16 of each grate, a reflecting wall 17, a secondary air blowing hole 18, and a cooling air nozzle 19. Has been done.

Normally, the gas outlet of the refuse incinerator 1 is connected to the gas cooling equipment 2 including the flow straightening wall 21, the reburning chamber 22 and the gas cooling chamber 23, and the reburning chamber formed on the back of the above-mentioned reflecting wall. A fly ash drop hole 24 penetrates through the bottom so as to be located on the post-combustion grate 15.

The melting device 3 is connected in front of the post-combustion grate 15. As shown in FIG.
A drop tube made of a refractory having a V-shaped cross section, and including a melting stage 31 in which the central surface of the horizontal part is inclined forward, a pusher 32 sliding on the horizontal part of the melting stage, and a water cooling jacket having a cooling nozzle 33 at the upper end. 34, and the front end of the melting stage 31 becomes a molten ash dropping section 35.

Reference numeral 4 is a high-temperature incinerator as a dedicated incinerator for wastes with high calorific value, such as waste plastic, which comprises a furnace body 41, a plastic hopper 42, a grate 43, a radiation wall 44 and a secondary combustion nozzle 45. And the secondary combustion chamber 46 located above the melting device 3 described above.

That is, the normal refuse incinerator 1 and the high temperature incinerator 4
Are installed side by side in a state of being connected to each other by the melting device 3 and the secondary combustion chamber 46.

Below the drop pipe 34, a wet ash carrying-out device 52 having a slag conveyor 51 built therein is disposed, and the lower end of the drop pipe 34 is water-sealed.

Below the grate lower hopper group 16,
A drop dust conveyor 53 for discharging the dust from each hopper is arranged, and an incinerator ash conveyor 54 for transporting the incinerated ash to be discharged is connected below the grate 43 of the high temperature incinerator 4, and The ends of the dust conveyor 53 and the incineration ash conveyor 54 are connected to the ash conveyor 55, respectively.

The ash conveyor 55 conveys the conveyed objects upward along the side wall of the incinerator body 11, and the end thereof is the post-combustion grate 1.
5 is connected to an ash drop port 56 (see FIG. 2) that opens upward.

The incineration ash conveyor 54 and the ash conveyor 55 described above constitute an unloading means for loading the incineration residue discharged from the high temperature incinerator 4 into the normal refuse incinerator 1.

Next, a melting processing method carried out by the melting incineration ash melting processing facility configured as described above will be described.

3 and 4 are explanatory views showing the general flow of dust, exhaust gas, air, ash, and slag in this equipment.

The high calorific value waste 61 such as plastics is
The high-temperature furnace combustion air 71, which is put into the furnace main body 41 from the plastic hopper 42, is ignited by a burner (not shown), and is preheated by an air preheater (not shown), burns violently to incompletely burn the high-temperature furnace. Exhaust gas 62 (unburned gas) is generated and goes to the secondary combustion chamber 46. The high temperature furnace exhaust gas 62 is discharged from the secondary combustion nozzle 4 above the secondary combustion chamber 46.
After the secondary combustion is caused by the oxygen supplied from 5 or the secondary air 72 whose temperature is raised by the air preheater (not shown) to become the melting device gas 63, and the generated high heat is radiated to the melting stage 31 by the radiation wall 44, It flows into the incinerator body 11 on the post-combustion grate 15.

At this time, the melter gas 63 is maintained at about 1400 ° C. or higher required for melting the incineration ash by controlling the supply amount of oxygen or the secondary air 72 by a controller (not shown). In this way, by controlling the temperature of the melting device gas 63, the temperature of the melting device 3 is maintained within a predetermined range, and as a result, it depends on the amount of residual combustibles in the incineration ash as in a direct-coupling type surface melting furnace. Therefore, a stable high temperature can be obtained, and the characteristics of the molten slag described later can be stabilized.

On the other hand, in the collection stage, in addition to the above-mentioned high calorific value waste, bottles and cans are separated by normal waste 64
Is usually put into the refuse incinerator 1 from the hopper 12, and is sent downward on the dry grate 13 and the combustion grate 14 in order. Then, by supplying the normal furnace combustion air 73 preheated by an air preheater (not shown) and receiving the above-described melting device gas 63 and the combustion heat held by the incinerator body 11,
It is dried and burned to generate the exhaust gas 65, and the rest becomes incineration ash 81, which falls on the post-combustion grate 15.

Next, in the front stage of the post-combustion grate 15, the incineration ash 81 is burned with the flame-retardant material remaining therein in the same state as above, and then transferred to the rear stage of the post-combustion grate 15. Then, since there is no air flow from the hopper below the grate in the lower part of the latter stage, it is not cooled and is irradiated with the above-mentioned melting device gas 63 to rise in temperature and falls into the melting stage 31.

High-temperature incinerated ash 81 dropped on the melting stage 31
Becomes a molten state due to the high heat of the above-described melting device gas 63, and while being pushed forward little by little by the pusher 32, it flows down along the inclination of the melting stage 31 and becomes molten ash 82 from the molten ash dropping section 35. Drop into the drop tube 34.

The molten ash 82 to be dropped is supplied to the cooling nozzle 3
3 is rapidly cooled and crushed with water or air 74 for cooling the slag to form a cooling slag 83. The cooling slag 83 drops into the ash discharging device 52 and is further cooled, and then is discharged outside the device by the slag conveyor 51. To be done.

Dust 84 dropped from each grate to the grate lower hopper 16 is transferred by a dust conveyor 53. Further, the high temperature incineration ash 85, which is the residue of the high calorific value dust 61 burned in the furnace body 41, is discharged from the high temperature incinerator 4 by opening and closing the grate 43, and is transferred by the incineration ash conveyor 54. , Along with the above-mentioned drop dust 84,
Lifted by the ash conveyor 55, the post combustion grate 15
From the ash drop port 56 located above, the unburned materials in the dust 84 and the high temperature incinerated ash 85 are completely incinerated on the incinerated ash 81 described above. Thus, the high temperature incineration ash 85 is dropped into the incinerator body 11 because the high temperature furnace exhaust gas 62 must be in an unburned state in order for the melting apparatus gas 63 to maintain a sufficiently high heat.
This is because the high calorific value waste 61 is incompletely burned, and as a result, the amount of unburned matter in the high temperature incineration ash 85 increases. That is,
If combustion control of the high temperature incinerator 4 is performed so as to reduce unburned substances in the high temperature incineration ash 85, it is not possible to generate the melting device gas 63 sufficient to melt the incineration ash. For this reason,
It is necessary to drop the high temperature incineration ash 85 into the incinerator body 11 to burn the unburned matter of the high temperature incineration ash 85.

On the other hand, the high-temperature melting apparatus gas 63 blown into the secondary combustion chamber 46 located above the melting stage 31 to melt the incineration ash 81 is blown into the furnace from the cooling air nozzle 19. After cooling the air 75 and the reflecting wall 17, the air 75 and the reflecting wall 17 are also cooled by the reflecting wall cooling air 76 blown into the incinerator body 11 and then mixed with the exhaust gas 65 generated from the dust layer to form the mixed gas 66.

After that, the mixed gas 66 is secondarily burned by the secondary air 77 of the normal furnace, and then sent to the reburning chamber 22 to complete the reburning of the remaining unburned gas to the gas cooling chamber 23. Sent.

Of the fly ash floating in the incinerator body 11 and the reburning chamber 22, the relatively heavy one is the reburning chamber 2
During the gas reversal in 2, it is separated from the gas flow and falls 8
6, it falls from the fly ash drop hole 24 onto the post-combustion grate 15 and is burnt together with the above-mentioned dust 84 and high-temperature incinerated ash 85.

FIG. 5 shows a different form from the above, in which the same members as those described above are designated by the same reference numerals and the description thereof is omitted.

In FIG. 5, the main difference from the above is that
A melting tank 91, which will be described later, is installed next to the melting stage 31, and the high temperature furnace exhaust gas 62 discharged from the high temperature incinerator 4 is flue 92.
It is a point to send via.

The melting tank 91 is made of refractory and has an open top, a bottom with an inclined portion for metal accumulation, and a slag opening 93 cut out at one of the upper ends.

In the melting tank 91, iron and the like are separated and settled at the bottom metal accumulation slope portion, so that relatively light weight Si,
Oxides such as Ca and Al float to the upper layer, and when the molten ash 82 reaches a certain level, it drops from the outlet 93 to the drop pipe 34 side.

The melting tank 91 is the same as that shown in FIGS.
It can also be installed in the melt processing equipment shown in.

In this description, the high temperature incinerator 4 is
Although the fixed furnace type is illustrated, any type may be used, and the slag cooling may be determined by the temperature of the secondary combustion chamber and the reuse form of the slag, and the ash discharging device 52 has been described as a wet type. It may be dry.

Further, the fly ash collected from an exhaust gas treatment device (not shown) normally discharged from the refuse incinerator 1 may be simultaneously treated, and the dust 84 and the high temperature incinerated ash 85 are separately collected together with the above-mentioned collected fly ash. It does not matter which method is used.

[0056]

As described above, according to the melting incineration ash melting method of the first aspect, the dry ash discharged from the incinerator is melted at a high temperature, so that the thermal efficiency is high. It is an effective utilization method of utilizing the combustion heat of high-heat-generation waste to be separately treated for melting, and can provide an economical method of using a small amount of electric power. Moreover, the part exposed to the high-temperature melting device gas is only in the melting device, and not only the range requiring high heat countermeasures can be localized, but the melting device gas is
No special exhaust gas treatment equipment is required because the waste can be treated on the incinerator side.

According to the refuse incineration ash melting treatment facility of the second aspect, the gas body is maintained at a temperature within a predetermined range by controlling the amount of oxygen or secondary air for secondary combustion. A stable high temperature can be obtained without being affected by the amount of residual combustibles in the incineration ash as in a melting furnace, and the characteristics of the molten slag are also stable.

According to the melting incineration ash melting treatment facility of claim 3, since the dry ash discharged from the incinerator is melted at a high temperature, the heat efficiency is high and the high heat-generating waste to be treated separately. This is an effective utilization method of utilizing the combustion heat of the above for melting, and it is possible to provide economical equipment with a small amount of power consumption. In addition, the area exposed to the high-temperature melting device gas is only in the melting device, and not only the range requiring high heat countermeasures can be limited, but since the melting device gas can be usually processed on the waste incinerator side, special exhaust gas treatment No equipment required. Furthermore, not using a high temperature air heater, etc. can eliminate high temperature corrosion of the metal part, and since it requires only simple equipment, there are few failures. At times, the incineration ash that has been completely incinerated can be discharged as it is, which does not lead to the shutdown of the entire refuse incineration facility.

According to the waste incineration ash melting treatment facility of the fourth aspect, the incineration ash discharged from the high temperature incinerator is provided with the carry-out means for bringing the incinerator ash into the normal waste incinerator, so that incombustibles and dust are removed. After complete burning, etc., batch melting processing is possible,
There is no risk of secondary pollution from waste.

[Brief description of drawings]

FIG. 1 is a sectional view showing an outline of a melting incineration ash melting facility according to the present invention.

FIG. 2 is a cross-sectional view showing an outline of the vicinity of a melting device.

FIG. 3 is an explanatory diagram showing a schematic flow of each substance of the melting incineration ash melting treatment facility according to the present invention.

FIG. 4 is a partially enlarged explanatory view showing a schematic flow of each substance of the melting incineration ash melting treatment facility according to the present invention.

FIG. 5 is a cross-sectional view showing another form of the melting device.

FIG. 6 is a drawing showing an outline of a conventional direct-coupling type surface melting furnace.

FIG. 7 is a diagram showing an outline of a conventional separate plasma melting furnace.

[Explanation of symbols]

 1 Normal refuse incinerator 3 Melting device 4 High temperature incinerator 46 Secondary combustion chamber 54 Incinerator ash conveyor 55 Ash conveyor 62 High temperature furnace exhaust gas (unburned gas) 63 Melting device gas

Claims (4)

[Claims] 1. A high temperature incinerator, which is equipped with a normal refuse incinerator that exclusively burns normal waste from which waste with high heat value is separated and removed and a high temperature incinerator that exclusively burns waste with high heat value. A method for melting waste incineration ash, which comprises melting the incineration ash discharged from a normal waste incinerator and a high-temperature incinerator by utilizing the radiant heat of the gas body. 2. The method for melting waste incineration ash according to claim 1, wherein the gas body is maintained at a temperature within a predetermined range by controlling the amount of oxygen or secondary air for secondary combustion. 3. A waste incineration ash melting treatment facility equipped with an ordinary refuse incinerator that exclusively burns ordinary waste from which high-calorific value wastes have been separated and removed, and a high-temperature incinerator that exclusively burns high-calorific value wastes. There is provided a melting device provided downstream of the normal refuse incinerator, and a secondary combustion chamber of the high temperature incinerator is provided above the melting device. 4. The waste incineration ash melting treatment facility according to claim 3, further comprising: an unloading unit that carries incineration ash discharged from the high-temperature incinerator into the normal waste incinerator. Equipment for melting incineration ash.