JP3725485B2 - How to remove dioxins - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for removing dioxins, and more particularly, to a method for removing dioxins from fly ash being transported by gas.
[0002]
[Prior art]
Conventionally, dust-containing air discharged from an incineration facility or the like is introduced into a dust-containing air chamber 3 of a dust collector (back-type dust collector 10 in the illustrated example) through an inflow port 11, filtered by a number of bag filters 14, and purified air. It is discharged to the outside through the discharge port 12 through the chamber 15.
[0003]
At this time, fly ash contained in the dust-containing air is a harmful substance including dioxins, and the bag filter 14 prevents the inflow into the purified air chamber 15 and adheres to the back filter 14.
[0004]
Fly ash containing harmful substances adhering to the back filter 14 is dropped to the lower part of the dust-containing air chamber 13 by applying a pulse to the bag filter 14 by air blowing means (not shown) provided on the purified air chamber 15 side. .
[0005]
Fly ash dropped in the lower part of the dust-containing air chamber 13 is temporarily stored in the relay hopper 17 through the rotary valve 16 and transferred to the transporter 19 through the release valve 18.
[0006]
Thereafter, the fly ash stored in the ash bunker was processed by being transported to the ash bunker 21 by a well-known air transport method and processed by melting or by thermal decomposition in the absence of oxygen.
[0007]
[Problems to be solved by the invention]
However, in the case of this conventional method, there is a problem that a large amount of energy is consumed when processing by melting, and the running cost is high, and the scale of equipment is large when performing the thermal decomposition in the absence of oxygen. There is a disadvantage that the device itself is expensive and the initial cost is high.
In view of the above, an object of the present invention is to provide a method capable of reducing both initial and running costs and removing dioxins with simple equipment.
[0008]
[Means for Solving the Problems]
To achieve the above object, the method for removing dioxins of the present invention, upon transport of fly ash in the pipe allowed to transport the gas in the transportation pipeline place microwave irradiation or ultraviolet dioxins decomposing and removing dioxins The removing method is characterized in that the transport pipe is constituted by a porous pipe that allows passage of the reaction accelerator and is sufficiently irradiated with ultraviolet rays or microwaves on the fly ash .
[0009]
The present invention having the above-described configuration can remove dioxins when pneumatically transporting fly ash containing dioxins.
[0010]
In this case, the reaction accelerator can be ozone or hydrogen peroxide.
[0011]
When ozone or hydrogen peroxide is used as a reaction accelerator, they are both strong oxidizers, and after decomposition they become oxygen and water, ensuring the efficiency of dioxin decomposition and removal without generating secondary waste. Can be increased.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a dioxin removal method of the present invention will be described with reference to the drawings.
[0013]
FIG. 1 is an overall view illustrating a method for removing dioxins according to the present invention.
Constituent elements similar to those of the conventional example are denoted by the same reference numerals and description thereof is omitted.
[0014]
The fly ash containing dioxins is stored in the transporter 19 and sent to the ash bunker 21 through the transport pipe 20 by a well-known air transport method in the same manner as before.
[0015]
At this time, the irradiation device 1 capable of selectively irradiating ultraviolet rays and / or microwaves at appropriate positions of the transport pipe 20 is installed.
Although the example of installation shows the example of installation of 1 unit | set, you may install 2 units | sets or more.
[0016]
The irradiation device 1 is installed to cover the transportation pipe 20 and includes an irradiation mechanism 2 that selectively irradiates ultraviolet rays and / or microwaves at appropriate positions, and the inner surface is a reflector 3 that reflects ultraviolet rays and / or microwaves. The shape is a cylinder or a cube.
[0017]
Reference numeral 5 denotes a reaction promoting substance supply pipe provided in the irradiation apparatus 1. The reaction accelerator H may be any substance that promotes dechlorination, that is, a reduction reaction, by separating hydroxyl groups (OH-) from alkaline substances in addition to ozone or hydrogen peroxide.
The reaction promoting substance supply pipe 5 may be provided in the transport pipe 20 on the upstream side of the irradiation apparatus 1 without being provided in the irradiation apparatus 1 as in the reference example shown in FIG.
[0018]
As shown in FIG. 2, the transport pipe 20 in the irradiation apparatus 1 is a perforated pipe 4 that allows the reaction accelerator H to pass therethrough and is configured to sufficiently irradiate the fly ash with ultraviolet rays and microwaves.
[0019]
Further, as in the reference example shown in FIG. 3, the transport pipe 20 in the irradiation apparatus 1 is a glass pipe 7, and the irradiation apparatus 1 is meandered to ensure sufficient irradiation time of ultraviolet rays and microwaves. It can also be configured.
At this time, the above-described porous pipe 4 can be meandered.
[0020]
One or more irradiation mechanisms 2 may be installed outside the irradiation apparatus 1 as shown in FIG.
[0021]
In the above configuration, the harmful dust D in the fly ash sent from the transporter 19 through the transport pipe 20 is mixed with the reaction accelerator H when reaching the irradiation device 1, and by the microwave irradiated from the irradiation mechanism 2. It becomes harmless dust C.
This is due to the fact that dioxins are decomposed by the action of locally heating the surface of the microwave object at a high temperature, for example.
[0022]
Dioxins adhere to the fly ash surface, and even if the fly ash center is at room temperature, the dioxins are sufficiently decomposed by heating the surface at a high temperature.
[0023]
When irradiating ultraviolet rays from the irradiation mechanism 2, an oxidizing agent is supplied as the reaction accelerator H.
Examples of the oxidizing agent include OH (OH radical), O ₃ (ozone), H ₂ O ₂ (hydrogen peroxide), HClO, and the like, and ultraviolet rays act as a catalyst.
[0024]
Active oxygen such as OH radicals can be generated by irradiating the oxidizing agent with ultraviolet rays.
[0025]
This is a method for decomposing and removing organic dioxins with active oxygen, and has the same effect as the accelerated oxidation method generally used as a DXN decomposition treatment method with water.
[0026]
As mentioned above, although the removal method of the dioxins of this invention was demonstrated based on the Example, this invention is not limited to the structure described in the said Example, The structure suitably in the range which does not deviate from the meaning. Can be changed.
[0027]
【The invention's effect】
As described above, when the dioxins removal method of the present invention is used, the dioxins are removed by irradiating microwaves or ultraviolet rays at an appropriate place in the transportation piping. Therefore, the method is simple, and both initial and running costs are conventionally required. As compared with this, it can be greatly reduced.
In addition, the dioxins removal method of the present invention can be applied by applying a slight modification to existing facilities.
[Brief description of the drawings]
FIG. 1 is an overall view illustrating a method for removing dioxins according to the present invention.
FIG. 2 is a partial cross-sectional view of an irradiation apparatus.
FIG. 3 is a partial cross-sectional view of a reference example of an irradiation apparatus.
FIG. 4 is an explanatory diagram of a conventional example.
[Explanation of symbols]
20 Transport piping H Reaction accelerator

Claims (2)

In the method of removing dioxins by decomposing and removing dioxins by irradiating microwaves or ultraviolet rays at appropriate places in the transportation piping when transporting fly ash that is transported by gas in the piping, the transportation piping is allowed to pass through the reaction accelerator. A method for removing dioxins, characterized by comprising a porous pipe that sufficiently irradiates fly ash with ultraviolet rays or microwaves . 2. The method for removing dioxins according to claim 1 , wherein the reaction accelerator is ozone or hydrogen peroxide.

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