JP3302944B2 - Method for treating incinerator effluent containing dioxins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to the incineration of refuse and the like,
The present invention relates to a method for treating fly ash and other ash, dust, and residues containing dioxins generated by an adsorption treatment.

[0002]

2. Description of the Related Art Dioxin (DXN) is contained in incineration ash generated in incineration facilities in 1983.
Announced in the year, and since then, its countermeasures have been considered as the most important environmental issues to be solved.

[0003] Dioxin has a form in which oxygen is sandwiched between two cyclic hydrocarbons (benzene rings).
Some of the eight hydrogen atoms have been replaced by chlorine. Two of the oxygen in between is called a dioxin and one is a furan, and both are called dioxins.

At present, incineration of refuse accounts for a large part of the generation of dioxins. Regarding refuse incineration, it is known that the generation of dioxins and precursors can be suppressed by high-temperature decomposition of dioxins and stable precursors by stable complete combustion.Furthermore, dioxins in generated exhaust gas are removed using exhaust gas treatment equipment, Alternatively, it can be disassembled.

The exhaust gas treatment equipment incorporates a bag filter, an exhaust gas cleaning device, an activated carbon tower, an activated coke tower, an adsorbent addition unit, etc., and the exhaust gas generated in the incinerator is passed through these devices. Finally, it is released from the chimney into the outside air.

[0006] Since a bag filter generally has higher dust collection efficiency than an electric dust collector and can collect finer dust, it is regarded as an extremely effective device for removing dioxins in exhaust gas. .

Activated carbon towers and activated coke towers are facilities for adsorbing dioxins on activated carbon or activated coke.
The exhaust gas cleaning device is not directly related to the treatment of dioxins, but mainly contains HCl, Hg, S contained in exhaust gas.
It is a facility to remove the O _X and the like. The adsorbent addition unit has a function of removing these harmful substances from the exhaust gas by introducing a chemical for adsorbing harmful substances such as dioxins into the exhaust gas.

[0008]

By the way, the ash, dust, residue and gas in the exhaust gas generated in the combustion furnace are subjected to a cleaning treatment by an exhaust gas cleaning device to remove the acidic gas, and in the activated carbon tower and the activated coke tower, Dioxins, Hg and other trace harmful substances are removed, and then, under temperature conditions that further reduce the resynthesis of dioxins, they are adsorbed and removed by bag filters, and the clean exhaust gas is released from the chimney into the outside air. .

As described above, even if the exhaust gas exhausted from the chimney becomes clean, it is subjected to post-treatment of the exhaust gas treatment equipment, for example, post-treatment of activated carbon or activated coke adsorbing dioxins, or trapped by a bag filter. After-treatment of fly ash is required.

[0010] The used activated carbon and activated coke have a high concentration of dioxins adsorbed thereon, so that the subsequent treatment is not easy.

Although the use of a bag filter can provide a stable and high removal efficiency of dioxins, a wrong treatment of dust and residue containing ash collected by the bag filter may become a new source of contamination. There is. on the other hand,
Ashes, dust and residues from incinerator effluents often contain environmental pollutants such as heavy metals, and mishandling of the effluents can also be a new source of pollution.

It is an object of the present invention to provide fly ash collected in a bag filter, fly ash generated by burning treatment of refuse in an incinerator, adsorption treatment of dioxins, adsorbent and other ash, dust, An object of the present invention is to provide a method for confining incinerator effluents such as residues in a solid body to prevent heavy metals and dioxins from leaking out of the solid body for safe treatment.

[0013] In order to achieve the above object, a method for treating incinerator effluent containing dioxins according to the present invention comprises the steps of treating an incinerator effluent containing dioxins having a mixing process, a stirring process, and a containment process. In the mixing process, ash and other dust, residue and glass cullet generated by combustion of refuse in an incinerator and adsorption process of dioxins are put into a container, and the container is heated.
This is a process to melt the glass cullet by heating , and the stirring process raises bubbles generated from heated ash, dust and residue.
And the agitation effect of the convection of the molten glass
The process of dispersing ash, dust, and residue in glass . The containment process is a process suitable for pouring molten glass in which ash, dust, and residue are dispersed into a mold, and is suitable for transportation, disposal, and storage.
This is a process for forming into a glass solid body.

[0014]

[0015]

[0016]

[0017] In addition, sealed rice processing, tilt the container, ash,
This is carried out by injecting molten glass in which dust and residue are dispersed into the mold from the rim of the container.

Further, sealed rice processing is performed by injecting ash container open bottom of the left container erecting posture, dust, the molten glass obtained by dispersing the residue in a mold.

Further, sealed rice processing, while the container erecting posture, performs by injecting glass cullet add-on, ash, dust, residue overflow the molten glass obtained by dispersing in into the mold It is.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, liquid waste 1 and solid waste 2 are put into respective incinerators 3 and 4 and incinerated,
The combustion gas is introduced into the gas washer 5.

In the gas washer 5, the acidic gas contained in the combustion gas is removed, and the exhaust gas from which the acidic gas has been removed is condensed through a condenser 6 and a demister 7 as necessary, and the mist is trapped. After passing through the bag filter 8, the dust contained in the exhaust gas, ash including fly ash, dust,
The exhaust gas from which the residue has been adsorbed and removed and which has passed through the bag filter 8 is subjected to a post-process if necessary, and is discharged into the outside air.

According to the present invention, a mixing process, a stirring process, and a containment process are sequentially performed on ash, dust, and residue containing dioxins. In this embodiment,
Fly ash (fly ash) captured by bag filter 8
Although an example of processing is described, the present invention is not limited to the processing of fly ash captured by a bag filter, the captured ash captured by a dust collector, activated carbon adsorbing dioxins, pulverized activated coke, dust, It can also be applied to the treatment of lime, adsorbents adsorbing dioxins, and other residues. In the present invention, ash, dust, and residue refer to powders and granules containing dioxins.

In the mixing process, ash and other dusts and residues generated by the burning of refuse in an incinerator and the adsorption process of dioxins, and in this embodiment, fly ash packed from a bag filter is mixed with molten glass. This is a mixing process, in which the molten glass contains glass cullet in a container.
Into the vessel and heat the vessel to obtain
Can be Stirring process, the ash while stirring the molten glass, dust, and the residue (fly ash) is a process of dispersing the molten glass, in the present invention, the heated ash, dust, from the residue
Stirring by rising bubbles and convection of molten glass
Ash, dust, and residue are dispersed in molten glass
Let The containment process involves pouring molten glass in which ash, dust, and residues are dispersed into a mold, and is suitable for transportation, disposal, and storage.
This is a process for forming into a solid glass body having a predetermined size.

First, as a pretreatment of the mixing process, the fly ash captured by the bag filter 8 is packed and, if necessary, dried in a dryer 9 or re-burned, and then the fly ash is melted. It is put into the furnace 10.

[0025] As shown in FIG.
And a heating source 12 for the container 11
Is heated by Joule heat generated by energizing the heater serving as the heating source 12, but may also be heated by plasma. In addition, gas,
The heat of combustion of oil, coke, and coal can be used, and these heat sources can be used in combination.

Referring to FIG. 2, the procedure of the mixing process and the stirring process performed subsequent to the mixing process will be described. FIG.
In (a), the mixing process is a process of charging the fly ash A packed from the bag filter into the container 11 and then charging the glass cullet GC to mix the two in the container 11. Mixing of fly ash A and glass cullet GC
This is performed by heating the container 11 and melting the glass cullet GC.

The fly ash A may contain lime used for the adsorption of acid gas or an adsorbent such as activated carbon used for removing dioxins.

In FIG. 2B, as the heating temperature rises, the glass cullet GC melts and becomes liquid. on the other hand,
The fly ash A is also heated to a high temperature, and the gas generated from the fly ash A rises as bubbles in the molten glass MG, and further, convection occurs in the molten glass MG as shown in FIG. The agitating process proceeds by the agitating action of the ascending motion and the convection in the molten glass MG, and finally, FIG.
As a result, a molten glass MG in which fly ash A is uniformly dispersed is obtained.

Normally, fly ash A itself also contains silicon, which is a vitrified substance, and fly ash A itself may be capable of vitrification to some extent by itself. By adding glass cullet GC additionally, the amount of glass components can be adjusted.

When the viscosity of the molten glass is low, separation and mixing failure may occur due to the difference in density of fly ash A, but the viscosity of the molten glass should be adjusted by setting the glass material and the melting temperature. Can be done. However, when the ash, dust and residue to be treated contain a sufficient glass component, it is not necessary to add and mix glass cullet again.

The stirring process can be performed without external stirring by the ascending motion of bubbles generated from fly ash and the convection generated in the molten glass MG. In FIG. 3A, the container 11 is tilted, and the molten glass MG is poured into the mold 13.

The molding die 13 performs a sealing process and has a circular concave portion on the die surface. Mold 1
As shown in FIG. 4, the molten glass MG poured into the mold 3 is shaped into a concave shape of the mold surface, and solidifies as a disk-shaped fixed glass solid body 14 enclosing the fly ash A.

The confining process is not limited to the case where a mold having a circular concave portion on the mold surface is used, and a mold having an arbitrary shape can be used. The solidified glass can be crushed by a thin cutting line to be processed into a fine glass solid.

The glass solid 14 obtained by the containment process contains fly ash A to which dioxins are adsorbed, and at the same time, harmful substances such as dioxins in the fly ash are contained in the glass solid. Can be The size of the solid body 14 is not particularly limited as long as it is a size suitable for transportation, disposal, and storage.
It is processed into a disk having a size of 5 cm in thickness. If the thickness of the solid body 14 is too large, it takes time to cool the solid body, and it also causes cracking.

In particular, fly ash contains a glass component and therefore has wettability with respect to molten glass. The surface of the fly ash is covered by a glass skin layer and macroscopically covers the surface of a solid body. Fly ash is hardly exposed and solidified. The same applies to ash, dust and residue generated in the incinerator.

The operation of pouring the molten glass from the container 11 into the mold surface of the molding die 13 during the encapsulation process is not limited to the above embodiment, and various other embodiments are possible.

FIG. 3A shows a case where the container 11 is a small container such as a crucible, for example. Since the container is small, the container 11 can be tilted to inject the molten glass MG into the mold 13. . However, when the container is large, it cannot be easily tilted by hand.

Therefore, in a large container, it is desirable that the molten glass can be poured into the mold surface of the molding die 13 in the upright posture after the mixing and stirring processes. FIG. 3B shows an example in which a stopper 15 is attached to the bottom of the container 11, and after stirring, the stopper 15 is opened to inject molten glass into the mold 13 from the hole of the container 11. The stopper 15 can be automatically opened and closed without being limited to a case where the stopper 15 is manually removed.

For example, an automatic opening / closing valve for converting a change in thermal expansion into a mechanical change is attached as a stopper 15 to a hole at the bottom of the container 11, and when the temperature becomes higher than a predetermined temperature after the glass is melted, it is automatically turned on. Then, the molten glass MG can be injected into the mold 13 by opening the automatic opening / closing valve. Further, when the molten glass is injected while the container is in the upright posture, the case is not necessarily limited to the case where the molten glass MG flows out from the bottom of the container 11.

FIG. 3C shows an example in which the molten glass MG overflows into the mold 13 by additionally charging the glass cullet GC into the container 11 while heating the container 11.

In the above, the processing of the fly ash trapped by the bag filter has been described in the embodiment. However, the present invention relates to the trapped ash trapped in the dust collector, activated carbon adsorbing dioxins, pulverized activated coke, Needless to say, the present invention can also be applied to the treatment of dust and residue such as an adsorbent which adsorbs dust, lime and dioxins. After the ash, dust, and residue containing dioxins were confined in a solid body using the treatment method according to the present invention, a dissolution test of heavy metals and the like from the glass solid body was performed. Table 1 shows the test results.

[0042]

[Table 1] (Note) ND: below detection limit, unit mg / l, A: Showa 4
6th Environment Agency Notification 59, B: JISK0102, C: 1974 Environment Agency Notification 64.

The meaning of dispersing ash, dust and residue in the molten glass means that when the ash, dust and residue to be treated contain glass components such as fly ash, they are mixed and stirred. As a result, ash, dust, and the residue themselves melt,
This includes the case where it is integrated with the molten glass and the case where the ash, dust and residue themselves are not melted but are incorporated into the glass and integrated.

[0044]

As described above, according to the present invention, fly ash generated by the burning of refuse is taken into the glass solid body, whereby harmful substances such as dioxins contained in the fly ash are contained in the glass solid body. Even if the glass solid treated by the method of the present invention is discarded, harmful components including dioxins do not leak from the solid, and post-treatment of fly ash captured by the bag filter can be performed. It can be done easily.

According to the present invention, the present invention can be applied not only to fly ash captured by a bag filter but also to processing of fly ash captured by a dust collector of an incinerator.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a procedure of a stirring process.

FIGS. 3A to 3C are diagrams illustrating an embodiment in which a molten glass is injected into a molding die and a sealing process is performed.

FIG. 4 is a view showing an example of a glass solid formed by the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid garbage 2 Solid garbage 3 and 4 Incinerator 5 Gas washing machine 6 Capacitor 7 Demister 8 Bag filter 9 Dryer 10 Melting furnace 11 Container 12 Heat source 13 Mold 14 Solid body 15 Plug A Fly ash MG molten glass GC glass cullet

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yoshio Sugita 1933-10 Shimonuma, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture NEC Environmental Engineering Co., Ltd. (56) References JP-A-2-175620 (JP, A) JP-A-8 JP-A-206628 (JP, A) JP-A-8-61634 (JP, A) JP-A-8-42832 (JP, A) JP-A-8-224561 (JP, A) JP-A-6-277650 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B09B 3/00-5/00

Claims (4)

(57) [Claims] 1. A method for treating incinerator effluent containing dioxins having a mixing process, a stirring process, and a containment process, wherein the mixing process includes burning of refuse and the like in an incinerator, and removal of dioxins. Ash and other dust and residue generated by the adsorption process
Put the glass cullet in the container, heat the container and
This is a process to melt the lascarlet , and the stirring process is a process that generates heat from ash, dust, and residue.
Utilizes the agitation effect of rising bubbles and convection of the molten glass
Is to disperse ash, dust, and residue in the molten glass.Containment treatment is a process in which molten glass in which ash, dust, and residue are dispersed is poured into a mold, and is suitable for transportation, disposal, and storage.
A method for treating incinerator effluent containing dioxins, characterized in that it is a process for forming into a solid glass body having a size . 2. The method according to claim 1, wherein the containment process is performed by tilting the container and injecting molten glass in which ash, dust, and residues are dispersed into the mold from the rim of the container. A method for treating incinerator effluent containing dioxins. 3. The containment process is performed by opening the bottom of the container while the container is in an upright posture and injecting molten glass in which ash, dust, and residues are dispersed into a mold. 2. A method for treating incinerator effluent containing the dioxins according to 1. 4. The containment process is performed by additionally adding glass cullet while keeping the container in an upright posture, overflowing molten glass in which ash, dust, and residues are dispersed, and injecting the molten glass into a mold. A method for treating incinerator effluent containing dioxins according to claim 1.