JP2005058979A - Detoxifying apparatus of injurious substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an economical detoxifying apparatus of an injurious substance, in which hypoxia can be maintained, and the amount of nitrogen produced as a substitution material can be reduced. <P>SOLUTION: According to this detoxifying apparatus of the injurious substance, a treating chamber in which vacuum can be realized has an infra-red heat treating chamber therein, and a certain amount of the injurious substance is pooled in a before-internal-processing reservoir and thereafter is subjected to vacuum anoxia to be heat-harmlessness treated. Further, the detoxifying is carried out by a batch processing as one cycle composing a throwing-in of the injurious substance into the heat treating chamber, reducing pressure, heating harmlessness treatment, pressure return, and discharging. The treatment is carried out under nitrogen atmosphere instead of treating in air, and nitrogen removes oxygen pooled and mixed in a nitrogen storage case by a nitrogen manufacturing means to increase the purity of nitrogen. Further, the harmlessness treatment is carried out by a method for making the injurious substance pass through the infra-red heat treating chamber and heating it with the infra-red ray. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The present invention relates to a method for treating incineration ash, and relates to a method for decomposing and removing organic chlorine compounds such as dioxin contained in incineration ash.

Dioxins remain in the incineration ash from incinerators that have not been treated for dioxins in the past, causing social problems. As a method for removing dioxins from the incinerated ash, a method of heating in a vacuum furnace shown in FIG. 4 is employed. (For example, see Patent Document 1)
In order to secure a vacuum, a method of mediating a small room provided with a double door when incineration ash is introduced into the furnace 40 is employed.
The air in the furnace was sucked with a vacuum pump to form a vacuum, and nitrogen was added to replace oxygen. When charging the incineration ash into the furnace, the furnace side door 44 is closed and the incineration ash is put into the input small chamber 43, then the atmosphere side door 45 is closed and the incineration ash is transferred to the furnace, and finally the furnace side door 44 is closed and input. The cycle is over. For discharge, a discharge small chamber 47 is provided, the atmosphere side door 48 is closed and ash is put into the discharge small room 47, then the furnace side door 46 is closed and the ash is transferred to the atmosphere side. Finally, the atmosphere side door 48 is closed and one cycle of discharge is performed. Finished.
Japanese Patent Laid-Open No. 2003-010825

However, in this method, the processing amount is determined by a cycle of opening and closing the door, and oxygen is mixed when incineration ash is charged. There was a limit.

A first object of the present invention is to provide an apparatus that increases the amount of processing per hour as compared with a conventional detoxifying apparatus.

The second problem is to provide an economically detoxifying device for harmful substances that can maintain low oxygen and reduce the production amount of nitrogen as a replacement material.

In order to solve the above-mentioned problems, the harmful substance detoxification apparatus of the present invention has an infrared heat treatment chamber in a treatment chamber capable of realizing a vacuum, and after storing a certain amount in a storage container before internal treatment, it is made oxygen-free under reduced pressure. It is characterized by heat detoxification treatment.

Further, the detoxification is performed by batch processing in which one cycle is input to the heat treatment chamber, pressure reduction, heat detoxification treatment, pressure return, and discharge.

Further, oxygen-free treatment is characterized by treating in a nitrogen atmosphere instead of treating in air.

Further, nitrogen is stored in a nitrogen storage container, and the mixed oxygen is removed by nitrogen production means to increase the purity of nitrogen.

Further, the detoxification treatment is performed by passing through an infrared heat treatment chamber and heating with infrared rays.

The effects of the present invention are as follows.
The amount of processing per hour can be increased compared to the conventional method.
A low-oxygen atmosphere optimal for the detoxification reaction can be easily realized.
Nitrogen production means to regenerate nitrogen as a replacement material is small and economical.

The harmful substance detoxification apparatus of the present invention comprises a processing chamber 2 with an infrared heat processing chamber 3, an internal storage container and a drive mechanism 8, and a door that can be opened and closed and sealed.
The processing chamber 2 is a chamber for decomposing and detoxifying harmful substances under reduced pressure and oxygen.
Incinerated ash before treatment is stored in a storage container 6 before external processing, and ash after processing is stored in a storage container 7 after external processing.

The hazardous substance detoxification apparatus of the present invention performs batch processing with one cycle of charging into the processing chamber 2, depressurization, heating detoxification, pressure return and discharge as proposed in claim 4.
If there are a plurality of pre-internal storage containers having at least one pre-internal storage container for receiving inside the processing chamber 2, the thermal efficiency can be increased.

The processing process will be described in order. The charging is performed by connecting the pre-external storage container 6 and the pre-internal storage container 4 with the entrance door 10 open, and moving the ash from the pre-external storage container 6 to the pre-internal storage container 4. When the movement of the ash is finished, the connection is disconnected and the entrance door 10 is closed.

Next, the processing chamber 2 is depressurized. At the same time as this operation, the depressurization is performed at the other end of the processing chamber 2 to discharge the processed ash, which is the final cycle of the batch processing, to the outside. This is performed after the doors 10 and 11 are closed at the time when both processes of discharging are completed. Depressurization is realized by operating the vacuum pump 21 and sucking the gas in the processing chamber, and the degree of vacuum is desirably reduced to 10 KP or less.

Next, the details of the heat detoxification process will be described.
After the pressure reduction is achieved, the process is started after the temperature of the infrared heat treatment chamber 3 rises to 600 ° C. or higher. Of course, when the process is continued and the temperature has reached 600 ° C. or higher, the process can be started after the pressure reduction is achieved.
The infrared heat treatment chamber 3 is a furnace made of a high-temperature heat-resistant ceramic and has excellent infrared radiation performance.
The infrared heat treatment chamber 3 sequentially feeds out the ash thrown into the inlet while rotating it, and is heated by infrared rays from the furnace wall during the movement to decompose and detoxify the dioxins.

The movement of the internal storage container during the heat detoxification process will be described with an example in which one storage container is provided at each of the inlet and the outlet.
The incinerated ash introduced from the external storage container is received in the pre-internal storage container 4, the processing chamber is decompressed, and then the incinerated ash is discharged and continuously sent to the infrared heat processing chamber 3.
In addition, the internal pre-treatment storage container 4 exchanges heat with the heat of the ash emitted from the infrared heat treatment chamber 3 and performs secondary heating.
The post-internal treatment storage container 5 is a container that receives the ash from the infrared heat treatment chamber 3, and is a container that transfers the ash in the processing chamber 2 to the outside of the processing chamber.

An example in which two containers each for the inlet and outlet are provided will be described with reference to FIG.
The incinerated ash charged from the external storage container is received by the first pre-internal storage container 4a, the primary pre-internal storage container 4a performs primary heating, and the second internal pre-storage container 4b is subjected to infrared heat treatment of the incinerated ash. It is a container that continuously feeds into the chamber 3.
At the time of entering the reduced pressure heating cycle, the first pre-internal storage container 4a and the second pre-internal storage container 4b are filled on the inlet side, and the post-first internal storage container 5a is empty on the outlet side, the second internal process The rear storage container 5b is filled.
The movement from the first pre-internal storage container 4a to the second pre-internal storage container 4b is performed after the introduction from the first internal pre-storage container 4a to the infrared heat treatment chamber 3 is completed.
The first post-internal storage container 5a is a container that receives ash from the infrared heat treatment chamber 3, and the second post-internal storage container 5b is a container that transfers ash in the processing chamber 2 to the outside of the processing chamber.
When the treatment is started, the ash that comes out of the infrared heat treatment chamber 3 is received in the storage container 5a after the first internal treatment.
As for the transfer of ash, after the processing chamber 2 is brought to atmospheric pressure, the second internal post-treatment storage container 5b is transferred to the external storage container, and after emptying, the first internal post-treatment storage container 5a is used after the second internal treatment. Transfer to the storage container 5b is performed.

The decompression oxygen-free means will be described.
Dioxin decomposition and detoxification in the processing chamber 2 are performed in an oxygen-free state. In the first method for realizing oxygen-free, air is introduced when returning the processing chamber to the atmospheric pressure, and suction is performed with a vacuum pump prior to processing, and nitrogen is injected into the processing chamber 2 for realizing oxygen-free. In this method, a small amount of nitrogen is required to replace nitrogen while the processing chamber 2 is sealed.

The present invention proposes claim 3 as the second means for realizing stronger oxygen-free. When returning the pressure in the processing chamber 2 to atmospheric pressure, nitrogen is entirely injected instead of the atmosphere.
It is uneconomical to replace the entire amount of nitrogen each time, and the suction gas of the vacuum pump 21 is collected in the nitrogen storage container 20. Nitrogen also serves as a heat exchange medium, which will be described later. Between the processing chamber 2 and the vacuum pump 21, a cooling means 23 for lowering the temperature of the suction gas and a dust collector 22 for removing fly ash and harmful gas are added.

The gas recovered from the processing chamber 2 to the nitrogen storage container 20 is mixed with oxygen or the like that has entered when the door of the processing chamber 2 is opened, and the purity of nitrogen is lowered.
In order to inject and circulate the nitrogen in the nitrogen storage container 20 into the processing chamber, it is necessary to remove oxygen and increase the purity. In addition, it is necessary to replenish the reduced amount of nitrogen.
For this reason, nitrogen production means 19 is added as proposed in claim 4. A part of the nitrogen storage container 20 is extracted and placed in the nitrogen production means 19, and the nitrogen having increased purity is returned to the nitrogen storage container 20. By this method, nitrogen having a maintained purity can be obtained.

If the storage container is moved to heat the incinerated ash or passed through the infrared heat treatment chamber 3, if it is in a powder state, harmful substances will be scattered in a state of adhering to the ash. For this reason, it is desirable to be in a solid state, and incineration ash in a solid state can be made by adding water to the incineration ash and granulating it.
Dioxin decomposition becomes more complete as the residence time in the high temperature state increases.
The incinerated ash is dried before entering the processing chamber 2, and the temperature reaches a decomposable temperature as soon as the temperature is raised, and the decomposition becomes complete.

Next, heat exchange according to claim 5 will be described.
The ash heated by the infrared heat treatment and the heat recovered from the infrared heat treatment chamber 3 are used to exchange heat with the incinerated ash before the treatment.
For heat exchange in a complete vacuum, heat conduction by contact or radiant heat can be used, and heat exchange by gas convection cannot be performed. This apparatus performs the process under a reduced pressure that does not reach a complete vacuum. For this reason, the gas existing inside is used as a heat exchange medium. One of the gases is nitrogen, and the other is water vapor in which water contained in the incinerated ash is evaporated in the infrared heat treatment chamber 3.
In the storage container outside the processing chamber, outside air is taken in, heat is recovered from the ash on the exit side, and the incineration ash on the entry side is warmed. Residual heat that warms the incineration ash on the entry side is returned to the outside air intake and further recovered.

The heat flow will be described in detail.
The first flow is nitrogen. Nitrogen injected into the processing chamber 2 enters the storage container 5 after internal processing through a pipe.
Part of the nitrogen that exits the storage container 5 after the internal treatment enters the infrared heat treatment chamber 3, and the rest of the nitrogen that exits the storage container 5 after the internal treatment enters the storage container 4 before the internal treatment. The discharged nitrogen then enters the pre-internal storage container 4. Nitrogen that has entered the pre-internal storage container 4 is sucked into the vacuum pump 20 and goes out of the processing chamber 2.
The nitrogen that has flowed out of the processing chamber 2 enters the heat exchanger 24 and exchanges heat with the air that forms the second flow.
Next, it enters the cooler 23 and the temperature is lowered to room temperature. Next, the fly ash mixed into the dust collector 22 is removed. Finally, the vacuum pump 21 is entered.

The second flow is air, which is sucked by the blower 27 attached at the end of this flow and exchanges heat with the ash in the container on the way or a heat exchanger. The taken outside air enters the heat exchanger 25 and exchanges heat with the heat taken in by this flow.
The air exiting the heat exchanger 25 enters the storage container 7 after external processing and takes away the heat of the ash, and then enters the heat exchanger 24 to exchange heat with nitrogen. Next, it enters the pre-external storage container 6 to take out the heat of the incinerated ash, then enters the heat exchanger 25, and finally the fly ash / dioxin is removed by the dust collector 26.

If the above processing is continued, the pre-internal storage container 4 becomes empty, and the post-internal storage container 5 becomes full. This is detected and the heat treatment is finished.
When discharging the ash in the processing chamber 2, the pressure is reduced during the processing, so it is difficult to open and close the door. In order to smoothly open and close the door, nitrogen is injected from the nitrogen storage container 20 into the processing chamber 2 before the door is opened and closed, and the atmospheric pressure inside and outside the processing chamber is matched.

Next, ash discharge will be described as a final step.
In the ash removal operation, the door is opened and the ash in the storage container 5 after the internal treatment is moved to the storage container 7 after the external treatment.
The ash is moved by opening the door and connecting the outlet external storage container 7 and the internal internal storage container 5 respectively.
After the movement of the ash is completed, the connection is cut off and the door is closed to complete one batch of processing.

In the disclosure example of the present invention, incinerated ash containing dioxin is disclosed as an example, but other fields of use include sludge containing hazardous substances, contaminated soil, sludge, meat and bone powder detoxification, or separation of heavy metals it can.

Diagram showing the configuration of this device Diagram showing the flow of vacuum and heat exchange of this device The figure which shows an Example with two internal storage containers each The figure which shows the structure of the conventional harmless device

Explanation of symbols

1 .... this apparatus, 2 .... processing chamber, 3 .... infrared heat treatment chamber, 4 .... storage container before internal processing, 4a..first storage container before internal processing, 4b..second storage container before internal processing. 5, a storage container after internal processing, 5a, a storage container after first internal processing, 5b, a storage container after second internal processing, a storage container before external processing, a storage container after external processing,
10 .... Inlet side door, 11 .... Outlet side door, 19 .... Nitrogen production means, 20 .... Nitrogen storage container, 21 ... Vacuum pump, 22 .... Dust collector, 23 ... Cooling means, 24 ... Heat exchange , 25 ... Heat exchanger, 26 ... Dust collector, 27 ... Blower,
40 ··· Conventional device, 41 ············································································································· Side door, 49 ... Air side door

Claims (5)

A harmful substance detoxifying device that has a vacuum chamber having a heating furnace, a storage container, and driving means inside, and intermittently throws in harmful substances and heat-treats them under oxygen-free negative pressure. Toxic substances are put into the storage container before the internal treatment from the outside of the treatment chamber in units of storage containers, and at the same time, the harmful substances after treatment are discharged from the internal storage container to the outside of the treatment chamber. A series of these processes are performed in which the pressure is reduced and oxygen-free, then the harmful substances in the pre-internal storage container are sequentially heated, and then the processing chamber pressure is returned to the atmospheric pressure after the pre-internal storage container is processed. A processing method for processing the above as one batch. Hazardous in using nitrogen as an oxygen-free means in the processing chamber, having a nitrogen storage container that recovers nitrogen discharged when the processing chamber is depressurized, and filling the nitrogen from the nitrogen storage container when the processing chamber pressure is equal to the external pressure Substance detoxification equipment. A detoxifying device for harmful substances that can circulate the nitrogen in the nitrogen storage container to the nitrogen regeneration means to remove oxygen and increase the purity of the nitrogen. A harmful substance detoxifying device having means for recovering the heat of a harmful substance leaving the heat treatment chamber and the heat of the heat treatment chamber and heating the harmful substance before the treatment.

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