JP2007225121A - Plasma melting treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a melting treatment device capable of dispensing with a melting auxiliary agent and the cooling of a melting portion, being easily handled, further being moved by a truck with, for example, a two-ton payload capacity, and melting waste in an in-vehicle state at a waste generation point. <P>SOLUTION: This melting treatment device is provided with at least a waste supply guide 13 for guiding the waste immediately under arc plasma 15 generated by a plasma torch 17, a waste supply device 11 capable of adjusting the supply of the waste according to the melted state of the waste, a melting portion 16 having a structure for immediately discharging the waste after melting without storing a melt after melting the waste, and a container 19 for storing slag discharged from the melting portion 16 and solidified. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a plasma melting apparatus for detoxifying hazardous waste such as asbestos at a place where waste is generated.

  In general, incineration ash generated by incineration of municipal waste, sewage sludge, or other waste in an incinerator is often landfilled. In addition, most of the waste containing asbestos harmful to the human body is currently landfilled. However, securing landfills for these wastes has become difficult year by year, and there is a demand for a method for reducing the volume of waste landfilled, that is, volume reduction treatment. In addition, when incineration ash is landfilled without being treated, the incineration ash itself contains harmful substances such as various heavy metals. And cause secondary pollution. In addition, asbestos is not affected by the landfill process. Therefore, the detoxification process and the volume reduction process of these hazardous wastes are required.

In view of this, a method for treating incinerated ash has been proposed in which incinerated ash is burned and melted by plasma in a melting furnace to reduce the volume and make it harmless.
For example, in the method of melting incineration ash etc. in a plasma melting furnace, a method using two plasma torches to perform stable melting (see Patent Documents 1 and 2), improving the pressure sealing structure in the melting furnace In order to reduce the installation space of the melting furnace (see Patent Document 3), a method using a circular melting furnace (see Patent Document 4) and the like have been proposed.
However, all of the proposals in Patent Documents 1 to 4 are large-scale melting processing apparatuses, in which a high-temperature molten metal is stored in a melting furnace, and the melting process is performed while using the heat from the molten metal together with the heat obtained from the plasma. Is what you do. For this reason, a large-sized cooling device for cooling the refractory material in the melting furnace is required to store the high-temperature molten metal, and in the type in which a plasma current is supplied to the molten metal itself, a large-scale power supply is required. It is necessary to provide it. For this reason, it cannot be used as an on-site melting treatment apparatus for waste generated in a small and dispersed manner.

On the other hand, as an on-site melting treatment method in which waste is generated, for example, excavating soil, placing a steel and ceramic container therein, and melting treatment using plasma heating (patent) Document 5), or a method of melting treatment using resistance heating in which an electrode is inserted and electrically heated (see Non-Patent Document 1) has been developed.
However, these methods are all intended for contaminated soil, and are melt processing methods that take several months and large expenses from the installation of the local treatment facility to the completion of the treatment. For this reason, it is not suitable as a treatment method for waste generated in a small-scale dispersion.

In addition, a method using a mobile small-sized waste treatment apparatus has also been proposed. For example, a vehicle-mounted incinerator (see Patent Documents 6 to 10), a movable waste crushing apparatus (Patent Documents 11 to 13). Have been proposed).
However, the proposals in Patent Documents 6 to 13 make it possible to move a processing apparatus such as an incinerator, and cannot detoxify harmful substances such as asbestos.

  For this reason, at present, there is no processing technology for hazardous waste such as asbestos generated in a small scale in urban areas, and a technology for processing at low cost locally is desired.

JP 2003-336826 A Japanese Patent Application Laid-Open No. 2004-257631 JP 2004-278860 A JP-A-7-243623 Special Table 2001-502020 Japanese Patent Laid-Open No. 10-122532 JP-A-7-198119 Japanese Patent Application Laid-Open No. 5-240417 Registered Utility Model No. 3036799 Registered Utility Model No. 3002971 Japanese Patent Laid-Open No. 2002-18851 JP-A-10-137624 JP-A-9-192528 Anfu, Terada, Kikawada, “Detoxification of Dioxin-Contaminated Soil by Geomelt Method”, Journal of the Japan Society of Mechanical Engineers, vol. 107, no. 1023, pp. 8-12, 2004

  Since the conventional plasma melting treatment apparatus for waste treatment is designed to store the melt, it is necessary to provide a large cooling device for cooling the melting furnace, and the portability is impaired due to the enlargement of the equipment. It was a drawback. Further, in order to melt waste with a high melting point, it is necessary to add a melting aid that is not waste in order to lower the melting temperature, resulting in an increase in the amount of waste generated. There were drawbacks. In addition, because the melt is inevitably in contact with the melting furnace for a long time, the melting furnace is eroded by the melt, and maintenance of the large-scale melting furnace is required on a regular basis. It was.

An object of the present invention is to solve the conventional problems and achieve the following objects.
In other words, the present invention does not require large-scale cooling of the melting part, and does not require a melting aid even for waste with a high melting point, and can be continuously melted, and regular maintenance can be performed. An object of the present invention is to provide an inexpensive waste melting treatment apparatus that can be reduced in size and weight and that is not required as much as possible.

Means for solving the problems are as follows. That is,
<1> A plasma melting processing apparatus comprising: a plasma generating apparatus capable of generating plasma; and a melting part that melts the object to be melted by irradiating the object with the plasma. The plasma melting apparatus is characterized in that it can be immediately discharged without storing the molten material after melting. It is configured to be able to discharge immediately without storing the molten material after melting, so that no melting aid is required even in melting processing of waste with a high melting point, and the amount of waste is increased unnecessarily. Melt processing is possible. In addition, since the corrosion of the melted portion caused by contact with the melt for a long time is eliminated, maintenance of the melted portion can be reduced as much as possible. Furthermore, since it is not necessary to provide a large cooling device for cooling the melting part, the facility can be downsized, the portability of the facility can be realized, and the facility cost can be reduced.
<2> The plasma melting apparatus according to <1>, further including a recovery unit that cools the melt discharged from the melting unit and stores the melt as a processed product. In the plasma melting treatment apparatus according to <2>, the melt-processed product can be recovered as glass scraps or recycled aggregate, and the recovery and disposal of the processed product is facilitated, or the processed product is recycled as aggregate Can be realized.
<3> The plasma melt processing apparatus according to <2>, wherein the melt is configured to be cooled by dropping into the recovery unit in the air. In the plasma melting processing apparatus according to <3>, the facility can be simplified by simplifying the recovery unit, and the processed product can be recovered in the form of particles, so that the processed product can be recovered, discarded, or recycled. Handling becomes easy.
<4> The plasma melting apparatus according to any one of <1> to <3>, further including an object supply device that sequentially supplies the object to the melting unit. By providing the supply device, the object can be continuously melted.
<5> The plasma melting treatment apparatus according to any one of <1> to <4>, wherein the plasma melting treatment apparatus is configured to be mounted on a vehicle and movable. Since the plasma melting apparatus is mounted on the vehicle and movable, the portable process can be performed.
<6> The plasma melting treatment apparatus according to any one of <1> to <5>, wherein the object is waste containing a hazardous substance. In the case where the object is a waste containing a hazardous substance, the plasma melting apparatus can be made harmless.
<7> The plasma melting apparatus according to any one of <1> to <6>, wherein the harmful substance is at least one selected from asbestos, dioxins, environmental hormones, and heavy metals. When the harmful material is asbestos, the acicular substances contained in asbestos harmful to the human body can be completely extinguished. In addition, when the hazardous substance is waste such as slate material containing asbestos, the melting point is high, so a large amount of melting aid, that is, a melting point lowering material is added to store a stable molten metal in the conventional plasma melting apparatus. There was a need to do. In the plasma melting apparatus of the present invention, since the melting process is performed without storing the molten metal, no melting auxiliary agent that has been conventionally required is required, and a stable melting process is possible. In addition, asbestos is used not only for building materials that are generated in large quantities as waste, but also for a wide variety of uses, albeit in small quantities. For example, a relatively small amount of asbestos waste is generated with the removal of asbestos used in the equipment, and further, asbestos waste is generated when the equipment using asbestos is discarded. Since these asbestos wastes are generated in small quantities in urban areas, they cannot be economically processed by collecting them and bringing them into intermediate treatment facilities or buried disposal sites. . Such asbestos waste generated in a small and dispersed manner can be melted at a low cost at the location where it is generated, and the risk of scattering due to an accident during transportation to an intermediate treatment facility or buried disposal site is completely eliminated. Can be eliminated.

  According to the present invention, conventional problems can be solved, and melting treatment can be performed on waste with a high melting point without requiring melt removal by not storing the molten metal, and cooling at the portion where the molten metal comes into contact is possible. Is unnecessary or can be simplified, safety, simplification of the melting system, compaction of the processing system, and weight reduction of the entire system can be achieved. A waste melting apparatus can be provided.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the embodiments.

(Plasma melting processing equipment)
As shown in FIG. 1, the plasma melting processing apparatus of the present invention includes at least a plasma generating apparatus 1, a melting object supply apparatus 2, a melting processing section 3, a melted and solidified product collecting section 4, and an exhaust gas processing apparatus 5. The Further, as shown in FIG. 2, the plasma generator includes a power source 6 for generating plasma, a gas cylinder 7 for supplying plasma gas, a plasma torch 10, a cooling water circulation device 8 for cooling the plasma torch, plasma It is comprised from the control apparatus 9 which controls gas flow volume, plasma output, etc. Among these, the structure of the said supply apparatus, the said melting process part, the said plasma torch, the said collection | recovery part, and the said waste gas treatment apparatus is shown in FIG.

<Supply device>
The supply device 11 is not particularly limited as long as the object to be melted has a guide 13 that is guided directly under a high-temperature plasma heating source, and can be appropriately selected according to the purpose. A structure in which the rod 12 is manually operated or a structure in which the supply rate is automatically controlled according to the amount of heat of the heating source can be used.

  The guide 13 preferably has a tubular structure, and is preferably a durable material that does not require maintenance.

The material of the supply guide is not particularly limited as long as it is not structurally affected by radiant heat from a heating source, and can be appropriately selected according to the purpose. For example, graphite, metal, and ceramics Etc.
Examples of the metal include copper, stainless steel, carbon steel, inconel, and nickel.
Examples of the ceramic include alumina, mullite, and silicon carbide.
Among these, stainless steel is preferable.

-Melting object supply means-
As a method for supplying the melted object, a screw feeder, a vibration feeder, and the like can be cited in addition to a method of simply pushing with the charging rod 12.
Among these, the method of automatically pushing with the charging rod 12 is preferable.

-Melting object receiving tank-
The molten object receiving tank 14 connected to the supply device is not particularly limited and may be appropriately selected depending on the purpose. For example, a structure in which the supply unit and the outside are not in direct contact with each other by a double damper method, etc. Is mentioned.

<Plasma generator>
The plasma generator is not particularly limited as long as it is an apparatus that generates arc plasma 15 and can be appropriately selected according to the purpose. For example, a method using direct current discharge can be mentioned.

  The arc plasma has an extremely high temperature of 5,000 to 10,000 ° C., and can melt an object to be melted extremely quickly. By adopting the arc plasma, it becomes possible to melt the object to be melted supplied from the guide 13 directly under the arc plasma 15 in a few minutes. For example, the melt is not stored in the waste containing asbestos. When melting at a temperature of 20 kg / hr, a processing speed of 20 kg / hr can be achieved.

  The arc plasma is often generated by a plasma torch 17, and its power source is mainly direct current, and some alternating current is also used. The plasma torch is (1) non-transition type using non-energized plasma (plasma jet) blown from the torch, and (2) energization formed between the torch and the object to be heated, using the object to be heated as one electrode. It is roughly divided into two types of transition types that use arc plasma in a state. Among these, the non-migrating type in which it is not necessary to provide a current-carrying electrode in the melt processing part by not using an object to be heated as an electrode, and the structure of the melting part is simplified is preferable.

<Melting part>
The melting processing unit 3 includes at least the arc plasma 15 for melting the non-heated material and the melting unit 16 having a structure that does not store the object to be melted.

  The melting part 16 is not particularly limited as long as it has a structure that does not store a melt, and can be appropriately selected according to the purpose. For example, as shown in FIG. 4, an inclined plate 21 is used. A method is mentioned. By using the inclined plate, the material to be melted can be discharged from the melted part immediately after melting.

  The inclination angle of the plate 21 is preferably 0 to 30 degrees, and more preferably 5 to 15 degrees.

  For example, as shown in FIG. 5, the plate 21 may be provided with a groove 25 or a hole for guiding the melt to the recovery unit, or to reliably guide the object to be heated directly under the arc plasma 26. A weir 27 may be provided.

  The plate 21 preferably has a certain height 23 relative to the melt recovery part. By providing the certain height 23, the molten product is cooled and solidified when it falls in the air, and the recovery of the molten solid product becomes easy.

  The height of the plate 21 with respect to the collection part is preferably 20 cm to 100 cm, and more preferably 30 cm to 70 cm.

  The plate 21 is preferably made of a durable material that does not require maintenance.

The material of the plate 21 is not particularly limited as long as it is not structurally affected by the radiant heat from the heating source, and can be appropriately selected according to the purpose. Examples thereof include metals and ceramics. Refractories are listed.
Examples of the metal include copper, stainless steel, carbon steel, inconel, and nickel. These may be provided with a local water cooling structure 24 or may not have a water cooling structure.
Examples of the refractory include alumina, mullite, and silicon carbide.
Among these, refractories such as alumina and mullite are preferable.

<Recovery Department>
The recovery unit 19 is not particularly limited as long as it has a structure capable of recovering the molten solidified product, and can be appropriately selected according to the purpose. For example, it is preferably a box-type structure provided with a recovery port.

  The recovery unit 19 is preferably made of a durable material that does not require maintenance.

The material of the recovery unit 19 is not particularly limited as long as it is not structurally affected by the radiant heat from the heating source, and can be appropriately selected according to the purpose. For example, metal, ceramics, etc. Refractories.
Examples of the metal include copper, stainless steel, carbon steel, inconel, and nickel.
Examples of the refractory include alumina, mullite, and silicon carbide.
Among these, refractories such as alumina and mullite are preferable.

-Means for recovering melt-solidified product-
There is no restriction | limiting in particular as a collection | recovery means of the melt-solidified product in the said collection | recovery part, Although it can select suitably according to the objective, For example, the method of scraping out manually is mentioned.

<Other devices>
-Exhaust gas treatment equipment-
It is preferable that a filter 20 for removing dust contained in the gas discharged from the melting processing unit is disposed in the melting processing unit 3 on the downstream side. The filter can remove fine particles generated by condensation of components evaporated when the melted material is melted.
Further, when the material to be melted includes a combustible component such as vinyl, it is preferable that a combustion furnace for burning combustible gas and a scrubber are disposed on the downstream side of the melting processing section. By the combustion furnace and the scrubber, the combustible gas contained in the exhaust gas can be completely burned, cooled and released.

  There is no restriction | limiting in particular as said combustion furnace, According to the objective, it can select suitably, For example, a burner type combustion furnace, an electric heater type combustion furnace, etc. are mentioned.

  There is no restriction | limiting in particular as said scrubber, According to the objective, it can select suitably, For example, scrubbers, such as a stored water type, a pressurized water type, a packed bed type, and a rotary type, are mentioned.

-Utility-
Examples of the apparatus associated with the plasma melting apparatus include a power supply for each device and a power supply for measurement control. These power sources receive power at the processing site or are supplied by a diesel generator.

-In-vehicle device-
The melt processing apparatus of the present invention can be melted without requiring a melting aid even for waste having a high melting point, and further, the melt processing system is simplified, the processing system is made compact and safe by not storing the molten metal. As a result, it is possible to reduce the weight of the entire system and, for example, a melting process in a vehicle-mounted state using a 2-ton truck is possible.

-Method of melting non-combustible hazardous waste-
A nonflammable hazardous waste melting method using an apparatus (FIG. 6) in which the plasma melting apparatus (FIG. 3) of the present invention is mounted on a vehicle will be described.
The arc plasma is generated by the plasma generator 1, and includes a gas cylinder 29 for supplying a plasma gas such as argon, a plasma generating power source 30, the plasma torch 32, and a cooling water circulating water device 31 for cooling the plasma torch. Consists of The plasma torch 32 may have a driving mechanism or may be fixed to the plasma melting processing unit 33.
The melting processing unit 33 includes the waste supply device 11, the melting unit 16, and the slag collection unit 19. The melt processing unit 33 is filled with an inert gas, and no exhaust gas that requires post-treatment such as nitrogen oxides is generated.
The waste supplied by the waste supply device is guided to the melting part 16 by the supply guide 13. The waste introduced to the melting part 16 is instantly melted and harmless by the irradiation of the arc plasma 15. The waste that has been detoxified by melting is discharged to the slag collecting unit 19 without remaining in the melting unit 16. New waste introduced by the supply guide 13 is introduced into the melting part 16 and the melting process is performed one after another efficiently. By the method described above, the toxic waste such as asbestos that has been melt-processed can be taken out by the slag collection unit 19 as slag that is completely harmless and can be recycled. Further, the exhaust gas discharged from the melting processing unit 33 is released into the atmosphere through the filter 34 for removing a small amount of dust.

-Detoxification of asbestos-
By using the in-vehicle plasma melting processing apparatus, it is possible to perform melting processing at a place where waste containing hazardous substances is generated. For example, in the case of waste containing asbestos harmful to the human body as an object to be melted, intermediate processing The risk of scattering due to accidents during transportation to facilities or buried disposal sites can be completely eliminated.

  We conducted an experiment to melt asbestos waste (Fig. 7) designated as specially controlled industrial waste using the plasma melting processing equipment, and analyzed the slag obtained after melting processing and the properties of dust generated during melting processing. Examined.

  The result of having observed the surface of slag using the scanning electron microscope is shown in FIG. From a photograph taken with an electron microscope, a fiber structure having a thickness of 0.02 to 0.03 μm and a length of 10 to 30 μm peculiar to asbestos is not observed at all.

  Furthermore, in order to confirm the presence or absence of asbestos from a macro viewpoint, the result of analyzing the crystal structure of the slag surface using an X-ray diffraction analyzer is shown in FIG. No peaks suggesting asbestos crystals (2θ = 12 °, 24 °, 37 °, 60 °) were observed, and asbestos was completely detoxified.

  Similarly, the result of observing dust collected from the filter using a scanning electron microscope is shown in FIG.

  From the electron microscope photograph of the dust, although the thick fibers of the filter are observed, the fiber structure of 0.02 to 0.03 micrometers in thickness and 10 to 30 micrometers in length, which is unique to asbestos, is quite similar to the slag. Not observed.

  The plasma melting apparatus of the present invention can be melted without requiring a melting aid even for waste with a high melting point, and by not storing the melt, it becomes possible to minimize maintenance and simplify the structure, Simplification, compactness, improvement of safety, and weight reduction of the entire system are possible because the melting processing system can be simplified. Disposal of asbestos that occurs in a small amount in a dispersed manner is possible. It can be suitably used for in-situ detoxification treatment for products.

FIG. 1 is a configuration diagram of a plasma melting processing apparatus. FIG. 2 is a configuration diagram of the arc plasma generator. FIG. 3 is a structural diagram showing an example of a plasma melting processing apparatus. FIG. 4 is a structural diagram illustrating an example of a melting processing unit. FIG. 5 is a structural diagram showing an example of a melting part. FIG. 6 is a schematic view showing an example of an in-vehicle plasma melting apparatus. FIG. 7 is an overview photograph of a slate material containing asbestos. FIG. 8 is an operational electron micrograph of the slag. FIG. 9 shows the result of X-ray diffraction analysis of slag. FIG. 10 is a scanning electron micrograph of dust.

Claims (7)

In a plasma melting apparatus comprising: a plasma generating apparatus capable of generating plasma; and a melting part that melts the object to be melted by irradiating the object with the plasma.
The said melting part is comprised so that it can discharge | emit immediately, without storing the said melted material after melting, The plasma melting processing apparatus characterized by the above-mentioned.   The plasma melting apparatus according to claim 1, further comprising a recovery unit that cools and stores the melt discharged from the melting unit as a processed product.   The plasma melting apparatus according to claim 2, wherein the melt is configured to be cooled by dropping in the air to the recovery unit.   The plasma melting treatment apparatus according to claim 1, further comprising an object supply device that sequentially supplies the object to the melting unit.   The plasma melting apparatus according to any one of claims 1 to 4, wherein the plasma melting apparatus is mounted on a vehicle and movable.   The plasma melting apparatus according to any one of claims 1 to 5, wherein the object is a waste containing a hazardous substance.   The plasma melting apparatus according to claim 6, wherein the harmful substance is at least one selected from asbestos, dioxins, environmental hormones, and heavy metals.