JP3943456B2 - Decomposition method of dioxins - Google Patents

Description

【００２７】
この表１により、スラリー状物のｐＨを７．５以上とした場合や、スラリー状物に界面活性剤を添加した場合は、分解率が良好であることがわかる。なお、ｐＨ無調整の場合は、ｐＨ６．７となったが、他の試料はいずれもそれよりも良好な結果を示した。
【００２８】
【発明の効果】
本発明のダイオキシン類の分解方法によれば、例えば処理雰囲気を還元性雰囲気にするための設備や加温のための加温設備等が必要でないため、処理装置の簡素化を図ることができ、かつ、室温でダイオキシン類を適切に分解処理できることから、処理に必要な熱エネルギの省エネ化を実現でき、処理コストを低減することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dioxin decomposition method capable of simplifying a processing apparatus, realizing energy saving of heat energy necessary for processing, and reducing processing costs.
[0002]
[Prior art]
Conventionally, for example, the following methods are known as methods for decomposing dioxins contained in, for example, fly ash discharged from a waste incinerator.
[0003]
The first method is, for example, a method (Hagenmeier process) in which dioxins-containing fly ash is made into a reducing atmosphere such as nitrogen gas and held at 320 to 400 ° C. for 1 to 2 hours.
[0004]
The second method is, for example, adding water to dioxin-containing fly ash to obtain slurry fly ash,
Thereafter, the slurry fly ash is adjusted to pH 9.5 or higher, and then this slurry fly ash is reacted at a temperature range of 100 to 350 ° C. for 2 to 60 minutes (Japanese Patent Laid-Open No. 6-142637).
[0005]
In the third method, for example, water and an inorganic oxyhydrogen salt compound are added to dioxin-containing dust collection ash, and after heat treatment in an oxidizing atmosphere after stirring in a temperature range of 200 to 600 ° C., the temperature is reduced to 100 ° C. or lower. This is a method of rapid cooling (Japanese Patent Laid-Open No. 10-151430).
[0006]
In the fourth method, for example, a dioxin-containing substance such as dioxin-containing incinerated ash is brought into contact with an amine compound or an ammonia compound at a temperature of 100 to 300 ° C. to react with chlorine in the dioxins, and dechlorination proceeds. (Japanese Patent Laid-Open No. 11-207300).
[0007]
[Problems to be solved by the invention]
However, in the conventional decomposition method of dioxins, for example, a facility for making the treatment atmosphere a reducing atmosphere, a heating facility for heating, and the like are necessary, so that the treatment apparatus tends to be complicated. In addition, since it is necessary to set the processing temperature to a relatively high temperature, there is a problem that a large amount of heat energy is required and the processing cost increases.
[0008]
The present invention has been made in view of the above points, and can simplify a processing apparatus, realize energy saving of thermal energy necessary for processing, and reduce processing cost. It aims at providing the decomposition method of a kind.
[0009]
[Means for Solving the Problems]
The method for decomposing dioxins according to claim 1, wherein water is added to a solid material containing dioxins so that the solid material becomes a slurry with a water content of 40% or more and iron powder is added to the solid material. the solid shape of the added dry matter per 0.5 to 15 wt% and the slurry-like material by adding a surfactant, in which the reaction at room temperature.
[0010]
The method for decomposing dioxins according to claim 2 is the method for decomposing dioxins according to claim 1, wherein the dioxins are allowed to stand for at least one week after the addition of water and iron powder.
[0011]
Method for decomposing dioxins as claimed in claim 3, iron powder were added and mixed from 0.5 to 15 wt% dry matter per the solid shape thereof on the solid-like material containing dioxins, water Is added so that the solid material becomes a slurry material having a water content of 40% or more, and a surfactant is added to the slurry material, and then left at room temperature for 1 week or more.
[0012]
Method for decomposing dioxins 請 Motomeko 4 wherein, in the method for decomposing dioxins according to any one of claims 1 to 3, the surfactant, anionic surfactants, cationic surfactants or nonionic It is a surfactant.
[0013]
And according to the method for decomposing dioxins of the present invention, for example, the equipment for making the treatment atmosphere a reducing atmosphere, the heating equipment for heating, etc. are not necessary, so that the treatment apparatus can be simplified. In addition, since dioxins can be appropriately decomposed at room temperature, the heat energy necessary for the processing is saved, and the processing cost is reduced.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0015]
In the method for decomposing dioxins according to the embodiment of the present invention, water is added to a solid material containing dioxins so that the solid material becomes a slurry with a water content of 40% or more and iron powder is added. adding 0.5 to 15 wt% dry matter per solid shape was and the slurry-like material by adding a surfactant, at i.e. room temperature conditions at room temperature (about 20 ° C.), allowed to stand over one week By reacting, the dioxins are decomposed and detoxified.
[0016]
Dioxins are decomposed when the temperature is set to 300 ° C. or higher in a reducing atmosphere essentially free of oxygen. To proceed with this decomposition, can be decomposed most conventional methods is an essential requirement for heating by heating equipment, the dioxins contained in the solid shape of such fly ash and soil without heating a room temperature The method was not known. The present invention is a method capable of efficiently decomposing dioxins at a processing temperature of about 20 ° C. at room temperature.
[0017]
And, more specifically, for example, the iron powder on the solid-like material containing the dioxins were added and mixed dry matter per 0.5 to 15 wt% of the solid shape thereof, iron water The water content is 40% or more with respect to the solid material before the addition of the powder , and the solid material is added so as to become a slurry, and the surfactant is added to the slurry (for example, an anionic surfactant, a cationic surfactant) This is a decomposition method in which dioxins are decomposed and detoxified by adding an agent or a nonionic surfactant) and then reacting by leaving it to stand at room temperature (about 20 °) for 1 week or longer .
[0018]
Here, the solid matter which is a dioxin inclusion containing dioxins is, for example, fly ash discharged from a waste incinerator, or soil contaminated with dioxins.
[0019]
The iron powder is, for example, a chemical reduction iron powder used for organic synthesis, a deoxygenation iron powder used for deoxygenation, or a warmer iron powder used for chemical warming. The iron powder preferably has a large specific surface area.
[0020]
The amount of iron powder added is preferably, for example, 0.5 to 15% by mass per dry matter of a solid material (for example, fly ash or soil) before adding water (before adjusting water content). Addition of 15% by mass or more does not shorten the decomposition period or improve the decomposition rate. Moreover, even if added in an amount of 5% by mass or more, the effect is small for the amount added, and 0.5 (or 1.0) to 5% by mass is more preferable in view of cost and decomposition efficiency. The dry matter amount is the mass of the portion excluding moisture of the solid matter.
[0021]
Et al is, although the addition of iron powder and moisture control is an important factor for the degradation of dioxins,
It is preferable to adjust the moisture after the iron powder is added. This is necessary to mix iron powder and fly ash (soil) homogeneously and to promote the decomposition of dioxins more effectively. When the moisture is adjusted,
Fly ash and soil may be partly dumped, and after that, homogeneous mixing with iron powder may not be achieved.
[0022]
In addition , regarding storage of a slurry-like material having a moisture content of 40% or more, storage in a tank or the like is preferable. However, in this case, a dehydration facility and the like are required in addition to the slurry transfer facility. For fly ash and dioxins in soil, it is necessary to conduct periodic simple analysis to confirm purification. In the case of storing the slurry-like material, a decomposition action due to contact with iron powder based on dissolution of dioxins can be expected, so that treatment by adding an alkaline or surfactant can be performed.
[0023]
In addition, it is not necessary to dare to remove incombustibles in incineration ash other than fly ash, rubble and pebbles in soil. It can be left as it is for a long time after mixing with iron powder and adjusting the moisture. The slurry concentration of the slurry is preferably a concentration that can be transferred by a pump, but the slurry concentration does not affect the decomposition reaction, and a slurry concentration suitable for the handling method may be selected. .
[0024]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples.
[0025]
Dense closed vial plurality prepared, fly ash dry weight per chemical reduction iron powder for together add fly ash 100g discharged from incinerators (dioxins concentration 3.2NgTEQ / dry g, water content 4%), respectively 5% by mass was added and the fly ash and iron powder were mixed well to obtain a mixture. After that, 90 ml of tap water is added to each sealed glass bottle to make the fly ash, which is a solid material, into a slurry-like material with a water content of 40% or more, then pH adjustment (related technology) , pH 7.5 adjustment (related technology) PH 8.5 adjustment (related technology) , anionic surfactant (for example, 47 mg dodecylbenzenesulfonic acid, 500 mg / l with respect to water), cationic surfactant (for example, cetyltrimethylammonium chloride 28 mg, in water) The nonionic surfactant (28 mg of polyoxyethylene lauryl ether, 300 mg / l with respect to water) was added, mixed and capped. And after leaving at room temperature for 100 days, the lid was opened, the fly ash in the sealed glass bottle was taken out, air-dried, and the dioxin concentration was measured. The results are shown in Table 1 .
[0026]
[Table 1]

[0027]
From Table 1 , it can be seen that the degradation rate is good when the pH of the slurry is 7.5 or more, or when a surfactant is added to the slurry. When the pH was not adjusted, the pH was 6.7, but all other samples showed better results.
[0028]
【The invention's effect】
According to the method for decomposing dioxins of the present invention, for example, the equipment for making the treatment atmosphere a reducing atmosphere and the heating equipment for heating are not necessary, so that the treatment apparatus can be simplified. In addition, since the dioxins can be appropriately decomposed at room temperature, it is possible to realize energy saving of the heat energy necessary for the processing, and to reduce the processing cost.

Claims (4)

0.5 per dry weight of the solid shape was iron powder with said solid material and water on the solid-like material containing the dioxins is added to a water content of 40% or more slurry product A method for decomposing dioxins, comprising adding 15% by mass and adding a surfactant to the slurry to react at room temperature. The method for decomposing dioxins according to claim 1, wherein the method is left for one week or longer after the addition of water and iron powder. Iron powder on the solid-like material containing the dioxins were added and mixed from 0.5 to 15 wt% dry matter per the solid shape thereof, the water solid material moisture of 40% or more A method for decomposing dioxins, comprising adding to a slurry and adding a surfactant to the slurry , and then allowing to stand at room temperature for 1 week or longer. The method for decomposing dioxins according to any one of claims 1 to 3, wherein the surfactant is an anionic surfactant, a cationic surfactant, or a nonionic surfactant.