JP3390767B2 - Waste treatment method and equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waste treatment method and apparatus for removing harmful hydrogen chloride (HCl) gas in exhaust gas generated during the drying process of waste to suppress the production of dioxins. Is.

[0002]

2. Description of the Related Art Techniques for crushing waste such as municipal solid waste and drying it for use as solid fuel are already known. Chlorine plastic is contained in the above waste,
Hydrogen chloride (HCl) gas is generated during drying. As a method for removing the HCl generated when the waste is dried, Japanese Patent Laid-Open No. Hei 7-1999
In Japanese Patent No. 316572, the waste is sent to a drier, hot air having an oxygen concentration of 14% or less and 350 ° C. or less is introduced, the waste is heated to 250 ° C. or more and dried, and HCl generated during the drying is generated in the latter stage. Disclosed is a method in which lime is absorbed in a hydrogen chloride removing device and treated.

[0003]

In the method described in this publication, since the waste is locally exposed to hot air of 250 ° C. or higher, the chlorine-based plastic contained in the waste is decomposed and harmful HCl is generated. , Dioxins are generated in the dryer by reacting with organic substances in the waste. Therefore, there is a problem that dioxins cannot be removed by the hydrogen chloride removing device in the latter stage.

The present invention has been made to solve these problems, and an object of the present invention is to mix an alkali compound which reacts with HCl with waste and generate local heating of the waste by hot air. By reacting a harmful gas such as HCl with a treatment agent (alkali compound) to form an alkali chloride, the generation of dioxins in the dryer is eliminated, and further, the reaction treatment agent is removed from the waste by a sorting machine, It is an object of the present invention to provide a waste treatment method and apparatus in which a treatment agent in dry exhaust gas is collected by a dust collector and separated from the exhaust gas.

[0005]

In order to achieve the above object, the waste treatment method of the present invention comprises the steps of mixing waste with a treatment agent containing an alkali compound or a treatment agent containing an alkali compound, and Directly contact the dried material with hot air from the mixture
It is configured such that it is introduced into a drier for drying and is dried, and at the same time, hydrogen chloride gas generated in the drying process is fixed and removed as an alkali chloride to suppress the generation of dioxins (FIG. 1, See FIG. 2). In this method, it is preferable to crush the waste and then mix the crushed waste with a treatment agent containing an alkali compound or a treatment agent containing an alkali compound (see FIGS. 1 and 2). The treating agent may be added and mixed before crushing the waste, or the treating agent may be added and mixed before and after the waste crushing step.

In these methods, it is preferable to introduce a mixture of the dried product discharged from the dryer and the reacted treating agent into a sorter to separate the dried product and the reacted treating agent (coarse particles). (See FIGS. 1 and 2). Further, it is preferable to introduce a mixture of the dry exhaust gas discharged from the dryer and the reacted treatment agent into the dust collector to separate the dry exhaust gas and the reacted treatment agent (fine particles) (see FIGS. 1 and 2). ). Furthermore, after crushing the dried material separated by a sorter, the incombustible material may be separated, and the crushed material in which the incombustible material is separated may be mixed with an additive for preventing decay such as lime to be molded ( See FIG. 2). In these methods, the alkaline compound is Ca (O
H) ₂ , CaO, CaCO ₃ , Mg (OH) ₂ , Mg
At least one of O, MgCO ₃ and CaMg (CO ₃ ) ₂ powder or particles is used.

The waste treatment apparatus of the present invention comprises a crusher for crushing the waste, a dryer for directly contacting the material to be dried with hot air for drying the crushed waste, and a dryer. In a waste treatment device provided with a dust collector for dedusting exhaust gas, in the crushed waste transport means on the outlet side of the crusher or / and the waste transport means on the inlet side of the crusher, a treatment agent comprising an alkali compound Alternatively, it is characterized in that a treatment agent adding means for adding a treatment agent containing an alkaline compound is connected (see FIGS. 1 and 2).

It is preferable that this apparatus further comprises a selector for separating the mixture of the dried product from the dryer and the reacted treating agent into the dried product and the reacted treating agent (FIG. 1). , See FIG. 2). In addition, a crusher for crushing the dried material from the sorter, a separator for separating incombustibles from the crushed material from the crusher, and a crushed material from which the incombustibles from the separator have been separated are prevented from decaying. In some cases, the constitution may further include an additive adding means for adding an additive for use with a molding machine, and a molding machine for molding a crushed product to which the additive has been added (see FIG. 2).

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and can be appropriately modified and implemented. FIG. 1 shows a waste treatment device according to a first embodiment of the present invention. Waste such as municipal waste containing chlorine-based plastics is crushed by a crusher 10 to a particle size suitable for drying, and the crushed material is mixed with a treatment agent containing an alkaline compound or a treatment agent containing an alkaline compound, and the resulting mixture is dried by a dryer 12. Then, the water in the waste is evaporated by directly contacting it with the hot air from the hot air oven 14. The temperature of the hot air is 250 to 600 ° C.

The treating agent is added to the downstream side of the crusher 10.
However, it may be added upstream of the crusher 10.
Or add both upstream and downstream of the crusher 10.
Good. 16 is a waste transport means (for example, screw controller)
Bear, belt conveyor, etc.), 18 is a crushing waste conveying means
(Eg screw conveyor, belt conveyor, etc.), 2
0 and 22 are processing agent adding means. Examples of treatment agents
For example Ca (OH)₂, CaO, CaCO₃, Mg (O
H) ₂, MgO, MgCO₃, CaMg (CO₃)
₂(Dolomite) and other powders (~ 10 μm) or particles
(~ 2 mm) is used. Moreover, as the crusher 10,
A uniaxial or biaxial shearing method or the like is used.

In the drying process, the temperature of the waste locally rises due to the introduction of hot air, so chlorine-containing plastics such as PVC or other organic chlorine compounds contained in the waste are thermally decomposed to generate HCl, Dioxins are generated by the reaction of this HCl with the organic compounds in the waste. Here, the alkaline compound reacts with HCl and takes in Cl to become a stable alkaline chloride. In this way, the alkaline compound reacts with HCl and Cl can be fixed as an alkaline chloride, so that dioxins are not produced.

The treating agent that has reacted with HCl is separated into a dried product and coarse particles of the treating agent by a sorting machine 24 such as a vibrating sieve installed in the downstream of the dryer 12 or a wind-powered classifier. The dried product is used as fuel or the like. On the other hand, the fine particles of the treatment agent entrained in the dry exhaust gas are separated and collected by a dust collector 26 such as a cyclone or a filter dust collector (for example, a bag filter). 28
Is a blower.

FIG. 2 shows a waste treatment device according to a second embodiment of the present invention. The present embodiment is applied to the production of solid waste fuel (RDF), in which the dried product from the sorting machine 24 is further finely crushed by the crushing machine 30, and is incombustible by the sorting machine 32 such as a vibrating sieve or a wind-powered classifier. After separating and removing foreign substances such as things, additives (for example, slaked lime, quick lime, etc.) are mixed to prevent spoilage, and the waste solidified fuel (RD
F) means that Cl or an alkali chloride (for example, C
It is intended to produce refuse solidified fuel (RDF) having a low content of non-combustible reaction products such as aCl ₂ ). 36 is an additive addition means. A uniaxial shearing type is used as the crusher 30, and a ring die type is used as the molding machine 34. Other configurations and operations are similar to those of the first embodiment.

[0014]

Since the present invention is configured as described above, it has the following effects. (1) The harmful HCl generated during the drying process of waste can be removed to suppress or reduce the production of dioxins. (2) Since harmful HCl and dioxins are removed or reduced, an exhaust gas treatment device is not required. Therefore, the drying process can be simplified, and the size and cost can be reduced. (3) By separating the treating agent that has reacted with a harmful gas such as HCl, nonflammable alkali chlorides do not remain in the dried product or the refuse solidified fuel (RDF).

[Brief description of drawings]

FIG. 1 is a systematic schematic configuration diagram of a waste treatment device according to a first embodiment of the present invention.

FIG. 2 is a systematic schematic configuration diagram of a waste treatment device according to a second embodiment of the present invention.

[Explanation of symbols]

10, 30 crusher 12 dryer 14 hot stove 16 Waste transportation means 18 Crushed waste transportation means 20, 22 Treatment agent adding means 24, 32 sorter 26 dust collector 28 blower 34 molding machine 36 Means for adding additives

─────────────────────────────────────────────────── --Continued from the front page (56) Reference JP 2000-8065 (JP, A) JP 60-166397 (JP, A) JP 11-106773 (JP, A) JP 10-311677 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B09B 3/00-5/00

Claims (9)

(57) [Claims] 1. A drier in which waste is mixed with a treating agent containing an alkaline compound or a treating agent containing an alkaline compound, and the mixture is dried by bringing hot air into direct contact with an object to be dried. A method for treating waste, which comprises introducing and drying, and at the same time, removing hydrogen chloride gas generated during the drying process to suppress the production of dioxins. 2. The waste treatment method according to claim 1, wherein after the waste is crushed, the crushed waste is mixed with a treatment agent containing an alkali compound or a treatment agent containing an alkali compound. 3. The waste treatment according to claim 1 or 2, wherein a mixture of the dried product discharged from the dryer and the reacted treating agent is introduced into a sorting machine to separate the dried product and the reacted treating agent. Method. 4. The waste according to claim 1, 2 or 3, wherein a mixture of the dry exhaust gas discharged from the dryer and the reacted treatment agent is introduced into a dust collector to separate the dry exhaust gas and the reacted treatment agent. Processing method. 5. The method according to claim 3, wherein after crushing the dried material separated by a sorting machine, the incombustible material is separated, and the crushed material from which the incombustible material has been separated is added and mixed with an additive for preventing decay. Waste disposal method. 6. The alkaline compound is Ca (OH) ₂ , C
aO, CaCO ₃ , Mg (OH) ₂ , MgO, MgCO
₃ and CaMg (CO _{3) 2} in waste treatment method according to claim 1 is at least one pulverulent body or granules. 7. A crusher for crushing waste and hot air for drying the crushed waste are directly applied to the material to be dried.
In a waste treatment device provided with a dryer for contacting and drying, and a dust collector for dedusting dry exhaust gas,
A treatment agent addition means for adding a treatment agent comprising an alkali compound or a treatment agent containing an alkali compound is connected to the crushed waste transportation means on the outlet side of the crusher or / and the waste transportation means on the inlet side of the crusher. A waste treatment device characterized in that 8. The waste treatment device according to claim 7, further comprising a separator for separating a mixture of the dried product from the dryer and the reacted treatment agent into the dried material and the reacted treatment agent. 9. A crusher for crushing the dried product from the sorter, a separator for separating incombustibles from the crushed product from the crusher, and a crushed product from which the incombustibles have been separated from the sorter. 9. The waste treatment apparatus according to claim 8, further comprising: an additive adding means for adding an additive for preventing spoilage to the product, and a molding machine for molding a crushed product to which the additive is added.