Information
-
Patent Grant
-
6787742
-
Patent Number
6,787,742
-
Date Filed
Friday, July 19, 200221 years ago
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Date Issued
Tuesday, September 7, 200419 years ago
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Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 219 628
- 219 629
- 219 630
- 219 635
- 219 647
- 219 649
- 219 651
- 373 141
- 075 1014
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International Classifications
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Abstract
A high-frequency induction-heating device preferably comprises an introduction part which introduces a gas to be treated; a pyrolysis part which pyrolyzes the gas to be treated; an induction heating coil provided around the outer circumference of the pyrolysis part so as to surround and heat the pyrolysis part, and an exhaust part which exhausts the gas having been decomposed in the pyrolysis part; wherein the pyrolysis part comprises a cylindrical body both ends of which are sealed, slits which communicate the interior with the exterior of the cylindrical body provided on the outer surface of the cylindrical body, and a communication pores to be communicated with an introduction tube which introduces the gas to be treated into the interior of the cylindrical body.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention concerns a high-frequency induction heating device and a device and method for using the high-frequency induction heating device to pyrolyze organic compounds. Specifically, this invention belongs to an art by which substances containing harmful compounds such as organohalogen compounds and other hazardous substance are decomposed in a gas phase by high-frequency induction heating.
2. Description of Related Arts
Organohalogen compounds, which contain chlorine, bromine, or other halogens, include many compounds that are designated as specified chemical substances or designated chemicals and also include many compounds that are causative agents of environmental problems. Representative examples include halogen-substituted aromatic organic compounds, such as dioxins, polychlorinated biphenyls, chlorobenzene, etc., and aliphatic organohalogen compounds, such as tetrachloroethylene, trichloroethylene, dichloromethane, carbon tetrachloride, 1,2-dichloroethylene, 1,1-dichloroethylene, cis-1,2-dichloroethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,3-dichloro-propene, etc.
These organohalogen compounds exist in various forms, i.e., solid, liquid, and gas forms.
For example, polychlorinated biphenyls (hereinafter referred to as “PCBs”), due to being highly resistant and chemically stable against acids and bases, extremely stable thermally, excellent in electric insulating properties, wide in the form of existence from liquid to solid, etc., have been used widely and in large amounts in numerous applications as insulating oils for transformers, capacitors, etc., plasticizers for electric cables, etc., and thermal media for a variety of processes in various chemical industries.
However, it has been found that hazardous substances are generated and environmental pollution is caused when PCBs and substances containing PCBs are combusted and that hazardous substances, originating from PCB's, become accumulated in human bodies by biological concentration through the food chain, especially through fishes, shellfishes, and other marine products. The production of PCBs was thus prohibited in 1972. Though problems of direct pollution due to the manufacture, etc. of PCBs were thus avoided, since PCBs have been used in a wide variety of uses due to their high degree of general usability and are difficult to decompose, the treatment and disposal of PCBs and substances containing PCBs have now become new environmental problems.
That is, if ordinary incineration treatment is performed to treat and dispose of PCBs and substances containing PCBs, dioxin and other hazardous substances are generated due to the low incineration temperature and these hazardous substances become discharged into the atmosphere along with flue gas, thereby causing further air pollution. On the other hand, if landfill disposal is performed, since PCBs have the properties of being excellent in stability and extremely difficult to decompose, the PCBs become eluted into the soil to give rise to soil, river, and marine pollution.
PCBs and products containing PCBs therefore could not be treated or disposed readily and the actual circumstances are such that PCBs and/or substances containing PCBs are simply stored upon being recovered by municipalities, etc.
Under such circumstances, various methods of treating PCBs are being examined. Representative decomposition treatment methods include high temperature incineration treatment methods, decomposition by enzymes and bacteria, treatment by chemicals (alkaline decomposition methods), etc., and among these, high-temperature incineration methods, with which PCBs are subject to incineration treatment at high temperature, were the most effective methods.
However, even with high-temperature incineration methods, there were problems that required improvement, such as the degradation of the furnace by the chlorine that is generated when PCBs are decomposed, the difficulty of furnace body management due to the requirement of high temperature (for example, 1600° C. or more) for treatment, the containing of large amounts of undecomposed PCBs in the incineration residue in some cases due to the incineration heat not being transmitted completely to the treated object, the generation of coplanar PCBs, dioxin, and other new hazardous substances in some cases by low temperature incineration caused by the inability to perform swift temperature control upon lowering of the incineration temperature due to poor control response to incineration temperature, etc.
Also, in the case of treatment of PCBs contained inside a container, such as in the case of a transformer, capacitor, etc., the PCBs could not be treated unless the PCBs were taken out of the transformer, capacitor, etc., and there were problems of contamination of workers during the work of taking out the PCBs and problems of treatment of PCBs remaining inside a transformer or capacitor after taking out the PCBs.
Also, a high-temperature incineration furnace is an extremely expensive device and a vast amount of space is required for the installation of a high-temperature incineration furnace. A high-temperature incineration furnace is also a device that takes an extremely large amount of time for the interior of the furnace to reach a desired temperature (that is, slow in startup) and takes an extremely large amount of time for the internal temperature to drop to ordinary temperature after heating has been stopped.
Thus in the case where organohalogen compounds are to be decomposed using a high-temperature incineration furnace, a large amount of the treated object had to be treated in a batch and the treatment of organohalogen compounds in a small-scale facility accompanied extreme difficulties. There were thus demands for a decomposition device and a decomposition method for organohalogen compounds with which heating to a predetermined temperature could be accomplished within an extremely short amount of time and which are compatible with equipment from comparatively small-scale equipment to large-scale equipment.
Also, these organohalogen compounds are contained in solids, liquids, and gases, and there were thus demands for a method of decomposing these organic compounds safely and without fail by practically the same operation method.
Furthermore, various organic compounds besides organohalogen compounds are causative agents of environmental pollution. There were thus demands for a pyrolysis device and pyrolysis method by which decomposition treatment of solids, liquids, and gases containing, for example, malodorous substances, such as indole, skatole, captans, etc., various environmental hormones, formaldehyde and other causative agents of sick house syndrome, waste oil, waste molasses, etc., can be carried out in a unified manner.
That is, there were strong demands for an organic compound pyrolysis device and pyrolysis method by which objects to be treated that contain organic compounds can be pyrolyzed and rendered harmless with a single device, regardless of the form (gas, liquid, or solid) of the organic compounds to be treated and the treated objects containing these organic compounds.
SUMMARY OF THE INVENTION
This invention provides a high frequency induction heating device suitable for use in a device for decomposing an organic compound, which heats and decomposes organic compounds in at least one pyrolysis zone each comprising at least one high-frequency induction heating device.
By the use of a high-frequency induction heating device, the degree of freedom of design of the pyrolysis zone is increased. In particular, the high-frequency induction heating device used in this invention can heat to a predetermined temperature, such as 1600° C., in an extremely short period, such as in 1 second or less, and moreover, enables the heating zone itself to be provided within a small space.
With this invention, by providing a means for gasifying solids and/or liquids at a stage upstream the heating zone, organohalogen compounds contained in the solids and/or liquids can be subject to pyrolysis treatment.
Thus a specific embodiment of this invention may have an arrangement with a gasifying device, for gasification of liquids or solids containing organic compounds, provided at a stage upstream the pyrolysis zone.
Such an arrangement enables decomposition treatment of organic compounds contained in gases, liquids, and solids to be performed with a single device. That is, treatment of organic compounds contained in a gas can be performed by the bypassing of the above mentioned gasifying device.
Also in the case where the organic compounds to be treated are organohalogen compounds that are comparatively difficult to decompose (for example, PCBs), this invention's device may be provided with two or more pyrolysis zones.
In this case, a preheating zone may be provided at a stage upstream a pyrolysis zone, which comprises this invention's high-frequency induction heating device. Additionally or alternatively, a pyrolysis zone, which makes use of radiant heat or comprises another high-frequency induction heating device, may be provided at a stage downstream the pyrolysis zone comprising this invention's high-frequency induction heating device. Also, it is also possible to provide a plurality of high-frequency induction heating devices within one pyrolysis zone
According to specific embodiments of the present invention, there provide the following novel high-frequency induction heating devices.
1. A high-frequency induction heating device comprising:
an introduction part which introduces a gas to be treated,
a pyrolysis part which pyrolyzes the gas to be treated,
an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and
an exhaust part which exhausts the gas having been decomposed in said pyrolysis part;
said pyrolysis part comprising a cylindrical body both ends of which are sealed, slits which communicate the interior with the exterior of said cylindrical body provided on the outer surface of said cylindrical body, and a communication pores to be communicated with an introduction tube which introduces said gas to be treated into the interior of said cylindrical body.
2. A high-frequency induction heating device comprising:
an introduction part which introduces a gas to be treated,
a pyrolysis part which pyrolyzes the gas to be treated,
an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and
an exhaust part which exhausts the gas having been decomposed in said pyrolysis part;
said pyrolysis part comprising a cylindrical body which introduces the gas provided so that the cross-section of the passage of said cylindrical body becomes smaller from the upstream towards the downstream.
3. The high-frequency induction heating device as set forth in Item
1
, wherein said cylindrical body is provided so that the cross-section of the passage of said cylindrical body becomes smaller from the upstream towards the downstream.
4. A high-frequency induction heating device comprising:
an introduction part which introduces a gas to be treated,
a pyrolysis part which pyrolyzes the gas to be treated,
an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and
an exhaust part which exhausts the gas having been decomposed in said pyrolisis part;
said pyrolysis part having a heating element having a plurality of through holes along the inside of the outer circumference of the diameter direction thereof and ceramic pipes inserted within said plurality of through holes and supported by pipe supporting plates accommodated therein.
5 The high-frequency induction heating device as set forth in Item
4
, wherein said pyrolysis part has pressure reducing means for reducing the pressure of the body.
6 The high-frequency induction heating device as set forth in Item
4
, wherein said pyrolysis part has compressing means for compressing the body by an inert gas.
7. The high-frequency induction heating device as set forth in Item
4
, wherein said pipe supporting plate has a guide member for introducing a gas to be treated into said ceramic pipe.
8. The high-frequency induction heating device as set forth in Item
7
, wherein said ceramic pipe is made of at least one member selected from the group consisting of silicon carbide and alumina.
9. The high-frequency induction heating device as set forth in Item
8
, wherein step part to be fit to spacers are provided on both ends of said heating element.
10. The high-frequency induction heating device as set forth in Item
9
, wherein said spacer comprises non-dielectric material and is formed from a flange having the plurality of through holes and cylindrical body.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A
is a graph showing the relation between the temperature and time when the inventive and prior art devices are operated for 8 hours, and
FIG. 1B
is a graph showing the relation between the temperature and time when the inventive and prior art devices are operated for 3 hours.
FIG. 2
is a flowchart, showing the flow of this invention's high-frequency induction heating device and an organic compound pyrolysis method that uses this heating device.
FIG. 3
is a schematic explanatory diagram, showing an organohalogen compound decomposition treatment device
1
of a first embodiment of this invention.
FIG. 4
is a schematic sectional view of gasifying means
2
.
FIG. 5A
is an enlarged view of the principal parts of an upper chamber
11
of gasifying means
2
and
FIG. 5B
is a perspective view of a heating container
12
used in organohalogen compound decomposition treatment device
1
.
FIGS. 6A and 6B
are perspective arrangement diagrams of a pyrolysis means
3
.
FIGS. 7A through 9B
are diagrams of embodiments of a heating unit of pyrolysis means
3
.
FIG. 10
is a schematic arrangement diagram of this invention's gaseous organohalogen compound decomposition treatment device
201
.
FIGS. 11A and 11B
are both sectional views of the principal parts of this invention's gaseous organohalogen compound decomposition treatment device
201
.
FIG. 12
is a schematic arrangement diagram of a third embodiment of this invention's gaseous organohalogen compound decomposition treatment device.
FIG. 13
is a schematic arrangement diagram of a fourth embodiment of this invention's gaseous organohalogen compound decomposition treatment device.
FIG. 14
is a schematic explanatory diagram of this invention's liquid organohalogen compound decomposition treatment device.
FIG. 15
is a diagram of an embodiment of a trapping device of this invention's liquid organohalogen compound decomposition treatment device.
FIG. 16
shows schematic explanatory diagrams of a pressure release valve and a trap provided in a treatment chamber of this invention's liquid organohalogen compound decomposition treatment device.
FIG. 17
is a schematic explanatory diagram of a safety device provided at the pressure reducing means side of this invention's liquid organohalogen compound decomposition treatment device.
FIG. 18
is a perspective external view of this invention's organohalogen compound pyrolysis device.
FIG. 19
is a perspective view, showing the internal structure of this invention's organohalogen compound pyrolysis device.
FIG. 20
is a longitudinal sectional view of FIG.
18
.
FIG. 21
shows diagrams of other embodiments of a guide member, related to this invention, for distributing and introducing exhaust gas, containing organohalogen compounds, to ceramic pipes, with
FIG. 21A
being a perspective view, showing a guide member of a first other embodiment wherein grooves are provided along the slope of a cone and
FIG. 21B
being a perspective view, showing a guide member of a second other embodiment having a dome-like protrusion.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The terminologies used herein have the following meanings.
The term “organic compound” used herein is a compound which has at least one carbon in the structure thereof in the form of a solid, liquid or gas, and which can be gasified at a reaction temperature (e.g., 1000° C. or more). The organic compounds intended herein are so called chemical hazards and include, but are not limited to, aromatic or aliphatic halogen compounds contained, for example, in incinerated ashes, exhaust liquid, and gas, such as PCBs, dioxins; halogen-containing polymers such as PVC, polyvinylidene chloride, polyvinylidene fluoride, specified chemical substances listed in the section of prior art, exhaust oils, exhaust liquid from alcohol distillation, and from squeezing olive oil and other vegetable oils, exhaust syrups, and any other residues from food processing.
The “high-frequency induction heating device” used herein is a heating device that makes use of a high-frequency induced current, in other words, a current that is induced in a conductor by a magnetic field that varies in time.
The techniques (including the device and the method) for pyrolyzing organic compounds using the high-frequency induction heating device according to this invention will now be outlined.
The high-frequency induction heating device according to this invention has a construction for example as shown in FIG.
18
.
Specifically, the device
401
by this invention comprises an introduction part
402
, into which dioxin-containing gas is introduced, a pyrolysis part
403
, which pyrolyzes the dioxin-containing gas that has been introduced into the above mentioned introduction part
402
, a discharge part
404
, which discharges the pyrolysis gas resulting from the decomposition at the above mentioned pyrolysis part
403
, and an induction heating coil
405
, which surrounds the main body
403
a
of the above mentioned pyrolysis part
403
from the exterior and heats a heating unit
403
f
in the interior, as the principal components.
Introduction part
402
comprises a dioxin-containing gas introduction entrance
402
a
and a duct
402
b
, which becomes enlarged in diameter from the upstream side to the downstream side, as the principal components.
A water-cooled type cooling jacket
402
c
for cooling introduction part
402
is provided at the outer circumference of duct
402
b.
Such a device is well-known in the art, but there is no example that such a device is used for pyrolyzing an organic compound from the view of energy such as electric power.
However, according to our studies, it has been discovered that when the high-frequency induction heating device is used, a time required for heating-up to a given temperature (i.e., start-up time) and a shut down time to stop the operation are very fast in comparison with the conventional devices for pyrolyzing organic compounds, and the device itself can be designed to be very small. Since it takes very short period of start-up time and/or shut-down time, the high-frequency induction heating device is not required to perform a continuous operation as in the conventional furnace. For this reason, the techniques for pyrolyzing organic compounds can be introduced into a relatively small-scale customer, which has entrusted a specialist with the treatment. Also, while the treatment has been conventionally performed when a prescribed amount of organic substances to be treated are accumulated, the introduction of the present techniques by the high frequency induction heating device makes it possible to treat the substance little by little. Particularly, upon using the high frequency induction heating device described in the following embodiment, the treatment efficiency is sharply increased.
For example, this is explained by referring to FIG.
1
A and
FIG. 1B
each showing the relation between the temperature and the time.
FIG. 1A
is a graph showing the relation between the temperature and time when the inventive and prior art devices are operated for 8 hours, and
FIG. 1B
is a graph showing the relation between the temperature and time when the inventive and prior art devices are operated for 3 hours.
As shown in
FIG. 1A
, in the conventional device, for example, 3 hours is required for preheating. In contrast, in the case of the high frequency induction heating device according to the present invention, only half hour is required to be heated to a prescribed temperature. Similarly, in the prior art, approximately 2 hors have been required for cooling down the device after the operation has been stopped, while the present device only requires 0.5 hours. For this reason, assuming that the treatment is carried out for the same period in each of the prior art device and the present device, practical treatment over a period of 7 hours can be done in the present device, whereas only 4 hours' treatment can be done in the prior art device. Furthermore, as shown in
FIG. 1B
, concerning 3 hour's total operation, the treatment can be done for 2 hours using the present device, while it is impossible to make any treatment using the prior art device.
In addition, as can been seen in
FIG. 1
, since the high frequency induction heating device according to the present invention has a good temperature following-up property, the treatment can be effectively done for example at 1600° C., after treatment, for example, at 1000° C. or vice versa.
Consequently, the use of the present device, i.e., the high frequency induction heating device, makes it possible to drastically increase the degree of freedom with regard to the operation schedule.
Moreover, the operation and the maintenance of the prior art device require skill, but those of the present invention are easy.
More over, the pyrolysis device (system) according to this invention has, for example, the configuration shown in FIG.
2
.
When the substance to be treated is in a solid form, including sol and gel, or a liquid form, the substance is gasified through an optional treating device and then is passed through the pyrolysis zone. On the other hand, when the substance to be treated is in a gas form, the substance is bypassed through the optional pretreatment device, and directly enters in the pyrolysis zone. The pyrolysis zone comprises an optional preheating device, at least one high frequency induction heating device and an optional post-heating device (preferably a radiation heating and/or high frequency induction heating device).
First, the substance is heated to a prescribed temperature through the optional preheating device, and then pyrolyzed through the high frequency induction heating device according to the present invention. Optionally, the substance remaining un-decomposed is completely decomposed through the latter post-heating device, after which the decomposed products are transferred to the post-treatment device known per se. The post-treatment device may be a filter for recovery of carbon, or a trapping zone containing adsorbing agent and/or absorbing agent.
According to this configuration, the substance in any form, i.e., in a solid, liquid, or gas form, can be treated only in one line comprising the present device.
This invention will now be described in detail by referring to specific embodiments. In the following embodiments, PCBs, which are difficult to be decomposed, will be exemplified. However, those skilled in the art will appreciate that this invention is applicable to various organic compounds having decomposition energy lower than those of PCBs.
(First Embodiment)
A first embodiment of this invention shall now be described with reference to
FIGS. 4 through 9
.
This invention's organohalogen compound decomposition treatment device is a device that renders harmless organohalogen compounds and/or substances containing organohalogen compounds without discharging any hazardous substances whatsoever from the discharge port of the device.
Here, the organohalogen compounds and/or substances containing organohalogen compounds that can be subject to decomposition treatment by this invention's organohalogen compound decomposition treatment device are not limited to just organohalogen compounds themselves, in other words, PCBs themselves (both solids and liquid) but also refer to substances containing PCBs (capacitors, transformers, paper, wood, and soil), mixtures with other oils, as in the case of PCBs used in chemical plants, etc., and dioxins and substances containing dioxins.
Also, a PCBs-gasified gas refers to a gas resulting from the gasification of PCBs.
As shown in
FIG. 3
, this invention's organohalogen compound decomposition treatment device
1
comprises a gasifying means
2
, pyrolysis means
3
, trapping means
4
, pressure differential generating means
5
, and pressure reducing means
6
as the principal components.
The gasifying means
2
of this invention's organohalogen compound decomposition treatment device
1
heats PCBs and/or a PCBs-containing substance P (shall be referred to hereinafter as “treated object P”) and thereby generates PCBs-gasified gas.
This gasifying means
2
comprises a lower chamber
10
and an upper chamber
11
, which is disposed adjacent the upper part of lower chamber
10
.
A heating container
12
, which contains the above mentioned treated object P, is housed and subject to replacement with inert gas including, but being not limited to, a rare gas such as helium, argon, and neon, carbon dioxide, and/or nitrogen in the above mentioned lower chamber
10
. Meanwhile, at the above mentioned upper chamber
11
, the treated object P, which has been subject to replacement with an inert gas and has been sent out from inside the above mentioned lower chamber
10
, is melted under a reduced pressure atmosphere to generate PCBs-gasified gas.
The shapes and sizes of this upper chamber
11
and lower chamber
10
are not restricted in particular, and, for example, a cylinder, quadratic prism, etc. may be selected as suited as the shape.
Also, though upper chamber
11
is smaller in size than lower chamber
10
in the present embodiment, these may be the same in size.
An opening
13
, which puts upper chamber
11
and lower chamber
10
in communication, is provided at the connection surface between lower chamber
10
and upper chamber
11
.
The shape of this opening
13
is not restricted in particular as long as it is a shape by which the heating container
12
that contains the above mentioned treated object P can be carried from inside lower chamber
10
to inside upper chamber
11
. A shape (substantially circular) and size that are the same as those of the planar section of the inner circumferential face of a high-frequency coil
24
, which shall be described later and is provided inside upper chamber
11
, are preferable.
A shutter
14
is provided in a manner enabling sliding in the horizontal direction at the roof surface of lower chamber
10
of this gasifying means
2
, that is, at the lower face of the above mentioned opening
13
, and upper chamber
11
and lower chamber
10
can thereby be partitioned as suited.
Also, a carry-in entrance
15
is provided at a side face of lower chamber
10
of gasifying means
2
. Thus treated object P, after being contained in heating container
12
, is carried inside lower chamber
10
via this carry-in entrance
15
.
Here, the material of heating container
12
is not restricted in particular as long as it enables heat to be transmitted efficiently to treated object P. Examples of such a material include, but are not restricted to, molybdenum, stainless steel, dielectric ceramics, carbon, etc. With the present embodiment a heating container
12
that is made of molybdenum is used.
The shape of heating container
12
is also not restricted in particular. However with prior-art indirect heating methods, when the distance between treated object P and the heating part is far, there was the disadvantage that temperature control response was poor and thus a temperature at which PCBs and oils boil could not be maintained.
Thus in order to resolve this disadvantage, the container used in the present embodiment has a plurality of blades
16
, each comprising a heat-resistant metal, provided at predetermined intervals along the inner peripheral surface of heating container
12
in a manner whereby they protrude towards the center of the container, and these blades
16
are arranged to contact treated object P to enable heating to be performed by efficient heat transfer (see FIG.
5
B).
In order to enable blades
16
to contact treated object P regardless of the size of treated object P, a thin, soft, rectangular plate is preferable as the form of blade
16
. Also with regard to the method of positioning the blades
16
, an arrangement is preferable wherein the ends at one side in the length direction of the above mentioned blades
16
are fixed along the inner peripheral surface of heating container
12
at suitable intervals and the respective ends at the other side are bent towards the bottom part of heating container
12
while facing toward the axial center of heating container
12
.
Alternatively, treated object P may be arranged to be carried into lower chamber
10
of gasifying means
2
with it being placed not inside heating container
12
but inside a drum made of the same material as heating container
12
.
A lift
17
is provided in a manner enabling rising and lowering inside lower chamber
10
of gasifying means
2
(see FIG.
4
). At substantially the central part of the upper surface of this lift
17
is provided an alumina pedestal
18
, on the upper surface of which is placed the heating container
12
that has been carried in from carry-in entrance
15
.
A circular packing
19
, for partitioning lower chamber
10
from upper chamber
11
while maintaining the sealing of upper chamber
11
, is provided at the upper part of lift
17
with alumina pedestal
18
being equipped at its central part.
The interior of upper chamber
11
can thus be sealed tightly by making the above mentioned packing
19
of circular shape contact the roof surface of lower chamber
10
upon opening the above mentioned shutter
14
provided at the opening
13
that puts lower chamber
10
and upper chamber
11
in communication and sending the heating container
12
, which contains treated object P, to the inner side of the below-described high-frequency coil
24
provided inside upper chamber
11
.
Lower chamber
10
is also provided with a vacuum exhaust pipe
20
for exhausting the air inside lower chamber
10
and an inert gas introduction pipe
21
for introducing inert gas into lower chamber
10
from a gas cylinder (not shown) filled with the inert gas such as described above. Valves
22
and
23
are provided respectively at the downstream side of vacuum exhaust pipe
20
and the upstream side of inert gas introduction pipe
21
.
The interior of lower chamber
10
can thus be replaced by inert gas to eliminate the air and the moisture contained in the air inside the treated object P that has been carried into lower chamber
10
and inside the lower chamber
10
.
The layout positions of vacuum exhaust pipe
20
and inert gas introduction pipe
21
are not restricted in particular as long as the positions enable inert gas replacement of the interior of lower chamber
10
.
With the present embodiment, the above mentioned vacuum exhaust pipe
20
provided at lower chamber
10
is connected, via the below-described pyrolysis means
3
, trapping means
4
, and pressure differential generating means
5
, to a vacuum pump
42
, which is the pressure reducing means
6
(see FIG.
3
). A reduced pressure atmosphere is thus arranged to be formed inside lower chamber
10
by means of this vacuum pump
42
.
The method for forming a reduced pressure atmosphere inside lower chamber
10
is not restricted to the above arrangement and an arrangement is also possible wherein a vacuum pump is separately provided for forming a reduced atmosphere inside just the above mentioned lower chamber
10
.
Also, in place of an arrangement wherein the supply of inert gas into lower chamber
10
is achieved by means of a gas cylinder (not shown) that is filled with inert gas and connected to inert gas introduction pipe
21
, inert gas may be supplied by means of a liquid nitrogen supply device (not shown) that is used in the below-described pressure differential generating means or by means of the gas resulting from gasification of the liquid nitrogen used in pressure differential generating means
5
.
The high-frequency coil
24
, into the inner side of which the heating container
12
that has been sent from inside lower chamber
10
by lift
17
is inserted, is disposed in upper chamber
11
of gasifying means
2
in manner whereby it spirals from the lower part to the upper part of upper chamber
11
and the space at the inner side takes on a substantially cylindrical form (see FIGS.
4
and
5
A).
Furthermore, a pressure sensor (not shown), such as a Pirani gauge for measuring the pressure inside this upper chamber
11
is disposed inside upper chamber
11
.
For the melting of the treated object P and gasification of PCBs by induction heating by high frequency, high-frequency coil
24
is connected to a high-frequency power supply (not shown) that is equipped with an inverter circuit and arranged to enable control of the heating temperature as suited.
The control of this high-frequency coil
24
is generally performed by a voltage amplification method. However in the case of a voltage amplification method, a discharge occurs inside the vacuum chamber when the voltage becomes 400V or more and this may impede the temperature control. Thus with the present embodiment, a current amplification method, with which such problems will not occur, is employed.
The employment of a high-frequency induction heating method for the heating for melting the treated object P provides various advantages such as the time required for raising the temperature from an ordinary temperature to 1000° C. being a short time of approximately 0.5 seconds, it being possible to concentrate the heating energy just to the inner side of high-frequency coil
24
, and it being possible to set temperatures in the range of 100° C. to 3000° C. (heat resistance temperature of carbon) in accordance to the power supply used and the heat resistance temperature of treated object P. The employment of a high-frequency power supply using an inverter circuit provides further advantages as it being possible to maintain the heating temperature within ±5° C. of a set value due to good following of the power supplying amount to temperature changes of the treated object P and it being possible to control the temperature rapidly and accurately in response to pressure rises within a furnace when PCBs-gasified gas is generated from treated object P, thus enabling the boiling point of treated object P at that pressure to be maintained in a stable manner.
A vacuum valve
25
is provided in a manner enabling opening and closing at the downstream side of upper chamber
11
of gasifying means
2
(see FIG.
3
).
This vacuum valve
25
is provided to put upper chamber
11
in communication with the above mentioned pyrolysis means
3
and enable the PCBs-gasified gas generated inside gasifying means
2
to be supplied to pyrolysis means
3
when a negative pressure state, due to the below-described pressure differential generating means
5
, or a reduced pressure state, due to vacuum pump
42
, is formed inside this invention's organohalogen compound decomposition treatment device
1
.
With organohalogen compound decomposition treatment device
1
of the present embodiment, an oil trap
26
is connected via a bypass piping to the piping that connects the above mentioned gasifying means
2
with the above mentioned pyrolysis means
3
.
Thus in the case where the PCBs-containing substance to be melted inside the above mentioned gasifying means
2
is a mixture with another low boiling point oil, etc., the low boiling point components contained in the PCBs-containing substance can be separated and recovered inside oil trap
26
by heating treated object P at a temperature less than or equal to the gasification temperature of the PCBs.
The pyrolysis means
3
of this invention's organohalogen compound decomposition treatment device
1
converts the PCBs-gasified gas generated at the above-described gasifying means
2
into harmless decomposition gas by contact pyrolysis by contact with a heating unit and by pyrolysis by radiant heat in the process of passage through holes formed in a heating unit.
This pyrolysis means
3
is connected to the downstream side of the above-described gasifying means
2
via vacuum valve
25
and is equipped in its interior with a heating unit
30
, which contacts and pyrolyzes the PCBs-gasified gas (see FIGS.
3
and
6
).
This heating unit
30
comprises a cylindrical body
31
, through the cylindrical interior of which the PCBs-gasified gas is passed through, a decomposing part
32
, which is disposed inside the cylindrical body
31
, and a holding member
33
, which holds the above mentioned decomposing part
32
inside the cylindrical body
31
.
Heating unit
30
of pyrolysis means
3
is heated across its entirety in order to pyrolyze the PCBs-gasified gas. The method for heating this heating unit
30
is not restricted in particular as long as heating unit
30
is arranged to be heated across its entirety. Microwave heating, dielectric heating, or induction heating, etc., may thus be selected as suited.
The heating temperature of heating unit
30
is not restricted in particular as long as the temperature enables cleavage of the benzene rings of the PCBs by heat and can be selected as suited from within a range of 1000 to 3000° C.
Heating unit
30
is thus arranged to employ the two pyrolysis methods of contact pyrolysis by contact with decomposing part
32
and pyrolysis by radiant heat in the process of passage between decomposing part
32
and cylindrical body
31
to pyrolyze the PCBs-gasified gas without fail.
The respective members (cylindrical body
31
, decomposing part
32
, and holding member
33
) that comprise heating unit
30
are made of tungsten, molybdenum, nickel, and alloys thereof, stainless steel, or a heat-resistant steel such as incoloy, etc. Also, those skilled in the art will appreciate that a trace amount of niobium may be introduced into the heat-resistance material to enhance creep resistance. The material can be suitably selected depending upon a particular use, i.e., the intended temperature, cost, etc.
With the present embodiment, decomposing part
32
takes on the shape of a truncated cone. This truncated conical decomposing part
32
is disposed inside the above mentioned cylindrical body
31
in an orientation such that the gap between the inner wall surface of cylindrical body
31
becomes gradually smaller from the upstream side to the downstream side of cylindrical body
31
, that is, in an orientation such that the cross-sectional area of the flow path of the PCBs-gasified gas becomes smaller from the upstream side to the downstream side.
This decomposing part
32
has one end thereof fixed to the above mentioned holding member
33
and is held inside cylindrical body
31
by holding member
33
being fitted in the cylindrical interior of cylindrical member
31
.
In order to make heat be transmitted readily in the process of heating the heating unit
30
, the truncated conical decomposing part
32
may be provided with the shape of a truncated cone with which the central part has been gouged out.
Furthermore in place of this truncated cone, a plurality of plates
35
may be provided in a radial manner as blades on the outer circumferential surface of cylinder as shown in
FIG. 7A
, a plurality of such arrangements may be equipped inside a cylinder from the upstream side to downstream side along the direction of flow of the PCBs-gasified gas, and the positions of the above mentioned blade plates may be shifted gradually to increase the area of collision (area of contact) with the PCBs-gasified gas.
Heating unit
30
of pyrolysis means
3
may also have an arrangement wherein a plurality of blades are provided on an axial rod
36
from the upstream side to the downstream side along the direction of flow of the PCBs-gasified gas as shown in FIG.
7
B and with these plurality of blades being housed within a cylinder and axial rod
36
being rotated by a motor, etc., (not shown).
In this case, the PCBs-gasified gas can be pyrolyzed while forcibly supplying the PCBs-gasified gas from the above-described gasifying means
2
by means of the rotation of axial rod
36
by the above mentioned motor.
An arrangement is also possible wherein, as shown in
FIG. 8
, the PCBs-gasified gas is introduced inside a circular pipe, then exhausted from holes provided on the outer circumferential surface of this circular pipe, and then passed through gaps between plates, disposed so as to cover the upper surfaces of these holes, to thereby contact pyrolyze the PCBs-gasified gas.
An arrangement is also possible wherein, as shown in
FIG. 9
, the PCBs-gasified gas is introduced inside a circular pipe, then exhausted from holes provided on the outer circumferential surface of this circular pipe, and then exhausted through slits provided on the outer circumferential surface of a cylinder that houses the circular pipe to successively perform contact pyrolysis and pyrolysis by radiant heat of the PCBs-gasified gas.
The method of configuring pyrolysis means
3
is not restricted in particular as long as the configuration is one by which the PCBs-gasified gas can be decomposed without fail and pyrolysis means
3
may be provided solitarily or in a plurality of serial or parallel stages.
In the case where the heating unit
30
equipped with decomposing part
32
, which is shown in
FIG. 6A
, is used as the heating unit of pyrolysis means
3
, a preferable method of configuring pyrolysis means
3
is to dispose two or more stages of pyrolysis means
3
a
and
3
b
, equipped with the same heating units
30
, in series. This is because in this case, the flow of the PCBs-gasified gas inside pyrolysis means
3
becomes a turbulent flow and the probability of the gas molecules of the PCBs-gasified gas contacting the heating unit is thus increased.
The trapping means
4
of this invention's organohalogen compound decomposition treatment device
1
traps decomposition products (halogens, carbon content, etc.,) contained in the decomposition gas resulting from pyrolysis of the PCBs-gasified gas at the above-described pyrolysis means.
This trapping means
4
includes a dry trap
40
and wet trap
41
.
The dry trap
40
of this trapping means
4
is formed by filling a circular pipe with a filler and the decomposition products contained in the above mentioned decomposition gas are adsorbed and trapped onto this filler. Examples of a filler that can be used include steel wool, activated carbon, nickel chips, etc.
With the present embodiment, nickel chips are used as the filler, and in this case, the carbon content in the above mentioned decomposition gas is adsorbed and recovered mainly as soot (carbon powder) by the catalytic action of nickel.
This dry trap
40
is interposed between the above-described pyrolysis means
3
and a butterfly valve
45
of the below-described pressure differential generating means
5
.
The above mentioned wet trap
41
of trapping means
4
traps, inside a liquid, the decomposition products contained in the above mentioned decomposition gas that could not be eliminated completely by the above-described dry trap
40
.
To be more specific, the decomposition gas, which has been rapidly cooled in the process of passage through the below-described pressure differential generating means
5
, is lead through an atmosphere in which an aqueous solution of sodium hydroxide is made into a mist to recover the halogens in the decomposition gas as salts and the carbon content as soot (carbon powder). When the content of halogens contained in the above mentioned decomposition gas can be presumed to be low, an arrangement is also possible wherein water is used in place of the above mentioned aqueous solution of sodium hydroxide.
This wet trap
41
is interposed between a filter
43
to be described below and vacuum pump
42
, which is the pressure reducing means
6
.
The organohalogen compound decomposition treatment device
1
of the present embodiment is of an arrangement equipped with the below-described pressure differential generating means
5
. Wet trap
41
is thus positioned at the downstream side of pressure differential generating means
5
. Thus in the case of a device arrangement wherein the above mentioned pressure differential generating means
5
is not equipped, the wet trap
41
may be connected directly to the downstream side of the above-described dry trap
40
.
Also, the salts and carbon powder recovered in aqueous solution by wet trap
41
are separated and recovered at a waste liquid treatment device (not shown). After separation of the salts and carbon powder, the aqueous solution of sodium hydroxide is arranged to be reused in wet trap
41
upon being adjusted to a predetermined concentration by addition of sodium hydroxide anew at a concentration adjustment device (not shown).
Thus by there being provided the dry trap
40
and wet trap
41
of trapping means
4
, the decomposition products inside the above mentioned decomposition gas are not released to the exterior of organohalogen compound decomposition treatment device
1
.
The pressure differential generating means
5
of this invention's organohalogen compound decomposition treatment device
1
makes the part from the above mentioned gasifying means
2
, through pyrolysis means
3
, and to trapping means
4
a closed system, isolates a part of the above-described trapping means
4
in this closed system to form an isolated part, and cools this isolated part to generate a pressure differential between the isolated part and non-isolated part inside the closed system.
This pressure differential generating means
5
comprises a butterfly valve
45
, a vacuum valve
46
, a piping
47
, which connects the above mentioned butterfly valve
45
with vacuum valve
46
, and a jacket type cooling pipe
48
, which is provided for cooling the interior of piping
47
.
By closing, the vacuum valve
46
of this pressure differential generating means
5
makes the part from the above-described gasifying means
2
, through pyrolysis means
3
, and to vacuum valve
46
a closed system.
By closing, the butterfly valve
45
of this pressure differential generating means
5
isolates the piping from butterfly valve
45
to the above-described vacuum valve
46
inside the closed system formed by the above mentioned vacuum valve
46
, thereby forming the isolated part.
By passage of liquid nitrogen or other coolant through its interior, the cooling pipe
48
of pressure differential generating means
5
rapidly cools the interior of piping
47
, that is, the isolated part formed by the above mentioned butterfly valve
45
and vacuum valve
46
.
Thus at pressure differential generating means
5
, by rapidly cooling the above mentioned isolated part, in other words, the interior of piping
47
, a pressure differential is generated between the isolated part and non-isolated part of the above mentioned closed system.
Thus when in the condition where a pressure differential has been generated, the butterfly valve
45
of pressure differential generating means
5
is opened and the isolated part and non-isolated part are put in communication, the PCBs-gasified gas that had been generated at the above-described gasifying means
2
is sucked in due to the pressure differential and is guided to the downstream side (pyrolysis means
3
and trapping means
4
) of gasifying means
2
.
This pressure differential generating means
5
thus performs the same function as the vacuum pump
42
of pressure reducing means
6
to be described later.
By thus guiding the PCBs-gasified gas by means of pressure differential generating means
5
, all of the treatment of PCBs in this organohalogen compound decomposition treatment device
1
are carried out within a closed system.
Thus even if undecomposed PCBs-gasified gas or other hazardous substances are generated, these will not leak out to the exterior of organohalogen compound decomposition treatment device
1
.
In addition to the above actions and effects, the rapid cooling of the interior of the above mentioned piping
47
in pressure differential generating means
5
provides the following effect.
That is, since the decomposition gas, which could not be trapped fully by the dry trap
40
positioned upstream the pressure differential generating means
5
, is rapidly cooled at the above mentioned piping
47
, the effect of preventing the generation of carbon tetrachloride (CCl
4
) due to recombination of the decomposition products contained in the decomposition gas is provided.
Also, for more efficient cooling of the above mentioned decomposition gas inside this piping
47
, a plurality of fins
44
may be provided in a detachable manner inside piping
47
to increase the area of contact with the above mentioned decomposition gas, and these fins
44
may also be arranged to adsorb and recover the above mentioned decomposition gas.
Here, various materials may be used as the material of fins
44
. Examples include stainless steel, nickel alloy, etc. When a nickel alloy is used, more of the decomposition products in the decomposition gas will be adsorbed as carbon due to the catalytic effect of nickel. A nickel alloy is thus preferable as the material of fins
44
.
Also, the method of rapidly cooling the above mentioned piping
47
is not restricted in particular as long as it is a method by which a negative pressure can be generated within the device by the rapid cooling of the interior of piping
47
.
Also, the pressure reducing means
6
of this invention's organohalogen compound decomposition treatment device
1
forms a reduced pressure atmosphere at a part extending from the above mentioned gasifying means
2
to trapping means
4
and replaces the interior of lower chamber
10
of the above-described gasifying means
2
with inert gas.
To be more specific, pressure reducing means
6
is a vacuum pump
42
, and this vacuum pump
42
has one end connected via vacuum valve
46
to a stage downstream the above-described pressure difference generating means
5
and has the other end connected to wet trap
41
to form a reduced pressure atmosphere inside this invention's organohalogen compound decomposition treatment device
1
and replace the interior of the above-described lower chamber
10
with inert gas.
A filter
43
, filled with activated carbon, is connected to the downstream side of the above-described trapping means
4
in order to make the exhaust gas that is generated during operation of the above-described vacuum pump
42
be exhausted outside the device after being treated completely of the impurities, etc., in the exhaust gas (see FIG.
3
).
This invention's organohalogen compound decomposition treatment method shall now be described.
The treated object P, which has been carried inside lower chamber
10
of gasifying means
2
via carry-in entrance
15
in the condition where it is contained in the above-described heating container
12
, is first subject to nitrogen replacement inside the above-described lower chamber
10
and is thereafter sent to the inner side of high-frequency coil
24
disposed inside upper chamber
11
. Treated object P is then melted by induction heating by high frequency under a negative pressure or reduced pressure atmosphere. In this process, the PCBs contained in the treated object P are gasified and PCBs-gasified gas is thus generated (gasifying step).
Since the interior of this invention's organohalogen compound decomposition treatment device
1
is maintained at a negative pressure or reduced pressure atmosphere, the PCBs-gasified gas that has been generated inside the above-described gasifying means
2
is sucked towards the pyrolysis means
3
that is positioned at a stage downstream the gasifying means
2
. The PCBs-gasified gas that has been supplied into pyrolysis means
3
is pyrolyzed into decomposition gas, comprising halogens and carbon, upon contact with the heating unit
30
, which is disposed inside pyrolysis means
3
and has been heated by microwave, etc., to a temperature at which PCBs are pyrolyzed, and is also pyrolyzed by the radiant heat in the process of passing through the gaps inside heating unit
30
(pyrolysis process).
The decomposition gas that has been generated at the above-described pyrolysis means
3
is supplied to the trapping means
4
that is positioned at the downstream side of pyrolysis means
3
. At dry trap
40
, which is disposed at an upstream stage of trapping means
4
and is filled with nickel chips, the carbon content in the decomposition gas is trapped as soot (carbon powder) by the catalytic action of nickel. The decomposition gas that could not be captured by this dry trap
40
is rapidly cooled at the pressure differential generating means
5
, disposed at a downstream stage, to restrain the generation of carbon tetrachloride from the decomposition gas. Then by passage through a mist of an aqueous solution of sodium hydroxide, which has been adjusted to a predetermined concentration, in wet trap
6
that is positioned at a stage further downstream, the chlorine in the decomposition gas is recovered as sodium chloride salt and the carbon content is recovered as carbon (trapping step).
(Second Embodiment)
A second embodiment of this invention shall now be described with reference to the attached drawings.
This invention's gaseous organohalogen compound decomposition treatment device is a device that pyrolyzes and renders harmless hazardous gases, such as organohalogen compounds supplied in the gaseous state, by high frequency induction heating.
A liquid organohalogen compound decomposition treatment device is a device that heats organohalogen compounds of liquid form to convert these compounds once into gaseous organohalogen compounds and renders these gaseous organohalogen compounds harmless by pyrolyzing the compounds by heating.
FIG. 10
is a schematic arrangement diagram of this invention's gaseous organohalogen compound decomposition treatment device
201
.
FIGS. 11A and 11B
are both sectional views of the principal parts of this invention's gaseous organohalogen compound decomposition treatment device
201
.
This gaseous organohalogen compound decomposition treatment device
201
comprises a gas introduction means
202
, pyrolysis means
203
, heating means
204
, and gas exhausting means
205
.
The gas introduction means
202
of gaseous organohalogen compound decomposition treatment device
201
guides gaseous PCBs and other various hazardous gases (shall be referred to hereinafter as “treated gas”) to the pyrolysis means
203
, which shall be described later.
As shown in
FIGS. 10 and 11
, with the present embodiment, gas introduction means
202
is a circular pipe
210
of predetermined length, and the treated gas is passed into the hole
211
of this circular pipe
210
and guided into the interior of a cylinder
212
of the pyrolysis means
203
, which shall be described later.
The material that makes up this circular pipe
210
is not restricted in particular as long as it is a material having such characteristics as being high in heat resistance, low in expansion and contraction due to heat, and not readily heated by induction. In the present embodiment, alumina is used.
Also, the diameter of circular pipe
210
may be selected as suited in accordance to the size of gaseous organohalogen compound decomposition treatment device
201
and the treatment amount of the treated gas. In the present embodiment, a circular pipe
210
of Φ28 mm is used.
The pyrolysis means
203
of gaseous organohalogen compound decomposition treatment device
201
applies the two pyrolysis stages of contact pyrolysis by contact with a heating unit and pyrolysis by radiant heat by passage through holes (slits
214
) formed in the heating unit to the treated gas introduced by the above-described gas introduction means
202
to convert the treated gas to a harmless gaseous substance.
The above mentioned heating unit of this embodiment is cylinder
212
, which is sealed at both ends (see
FIGS. 10
to
11
B). Circular pipe
210
, which is the above-described gas introduction means
202
, is inserted into one end face of cylinder
212
and the tip of the inserted circular pipe
210
is positioned so as to face the other end side of the interior of cylinder
212
.
At the outer circumferential surface of cylinder
212
at the one end side into which the above-described circular pipe
210
is inserted, a plurality of slits
214
, which put the interior and exterior of cylinder
212
in communication, are provided from one end side towards the other end side of cylinder
212
.
These slits
214
are provided at two parts at positions that are point symmetric with respect to the central part of cylinder
212
(see FIG.
11
A).
The treated gas that has been supplied to this heating unit is thus always supplied to the other end side of the interior of the above-described cylinder
212
. The treated gas that has been guided to the other end side of the interior of cylinder
212
flows inside the cylinder
212
and moves from the other end side to the one end side at which the above mentioned slits
214
are provided and are exhausted to the exterior of cylinder
212
by passage through these slits
214
.
Here, since the cylinder
212
is heated by the heating means
204
to be described later, the treated gas that has been guided inside cylinder
212
contacts the inner wall surface of the heated cylinder
212
and becomes pyrolyzed in the process of moving inside cylinder
212
to the side (one end side) at which the above-described slits
214
are provided. Also, even if the treated gas does not contact the inner wall surface of cylinder
212
, since the slits
214
provided in cylinder
212
are heated to a high temperature due to the reasons given below, the treated gas is decomposed by radiant heat in the process of passage through the slits
214
.
Treated gas is thus not exhausted from slits
214
of cylinder
212
but only decomposition gas, which has been decomposed to a harmless state, is exhausted from slits
214
.
Here, the diameter of cylinder
212
may be selected as suited in accordance to the size of the device and treatment amount of treated gas. In the present embodiment, a cylinder
212
of Φ35 mm is used.
Also, the material that makes up the heating unit may be selected as suited from tungsten, molybdenum, nickel, and alloys thereof, stainless steel, or a heat-resistant steel such as incoloy, etc.
The use of molybdenum for the heating unit provides such advantages of molybdenum as having a heat resistance temperature of 2800° C. and thus being better in heat resistance in comparison to other materials and providing white light upon being heated and being high in energy density, thereby enabling decomposition of the treated gas by radiant heat even if contact is not made.
Also, when incoloy, which is a nickel alloy, is used for the heating unit, the advantage that the organic substances in the treated gas that contacts the heating unit are converted into and recovered as carbon by the catalytic action of nickel is provided.
Thus it is more preferable to use incoloy than stainless steel and more preferable to use molybdenum than incoloy as the material that makes up the heating unit.
Also, the number and slit width of the slits
214
provided in cylinder
212
may be selected as suited. With the present embodiment, the slit width is 2 mm.
With the present embodiment, a high-frequency coil
215
, which is the heating means
204
, is provided at a position that is separated from the outer circumferential surface of the heating unit by a predetermined distance as shown in FIG.
10
. Thus when a high-frequency current is made to flow through high-frequency coil
215
for heating the heating unit, an eddy current arises on the outer circumferential surface of cylinder
212
of the heating unit.
In this process, since a current cannot flow at the slit
214
parts, current becomes concentrated at the respective parts between slits
214
(these parts shall be referred to hereinafter as “outer circumference parts
216
”). As a result, the outer circumference parts
216
become heated to a higher temperature than other parts of cylinder
212
. The spaces inside the slits
214
thus become high temperature bodies as well.
Thus even if the treated gas is guided to these slits
214
without contacting the inner wall surface of the above-described cylinder
212
, the treated gas will be pyrolyzed without fail by the radiant heat in the process of passage through slits
214
.
Furthermore, a rifling
217
may be provided on the inner wall surface of cylinder
212
from the other end side towards the one end side of cylinder
212
as shown in FIG.
11
B. In this case, the treated gas that has been supplied to the other end side of cylinder
212
will be guided to slits
214
provided at the one end side while being stirred in spiraling manner by the existence of rifling
217
. The chances of contact of the treated gas with cylinder
212
is thus increased and the treated gas is contact pyrolyzed more efficiently.
The heating means
204
of this gaseous organohalogen compound decomposition treatment device
201
heats the above-described pyrolysis means
203
.
This heating means
204
comprises an alumina chamber
218
, which houses the above-described pyrolysis means
203
in its interior, and a high-frequency coil
215
, which is wound in spiraling manner from one end side towards the other end side of alumina chamber
218
at a position separated from the outer circumferential surface of alumina chamber
218
by a predetermined distance (see FIGS.
10
and
11
).
This high-frequency coil
215
is connected to a current controlled type high-frequency power supply (not shown). Thus by changing the power that is made to flow through high-frequency coil
215
, the pyrolysis means
203
housed inside the above mentioned alumina chamber
218
is induction heated and thus heated as suited to a desired temperature.
The gas exhausting means
205
of this gaseous organohalogen compound decomposition treatment device
201
guides the treated gas into the above-described pyrolysis means
203
and makes the decomposition gas, formed by decomposition of the treated gas at pyrolysis means
203
, be exhausted from the above-described pyrolysis means
203
.
In the present embodiment, this gas exhausting means
205
is a general vacuum pump (not shown) that is connected via a piping to the downstream side of the above-described pyrolysis means
203
.
This vacuum pump sucks in the treated gas via circular pipe
210
of the above-described gas introduction means
202
and guides the treated gas into cylinder
212
of the above-described pyrolysis means
203
. The vacuum pump then sucks out and makes the decomposition gas, which arises from the pyrolysis of the treated gas inside cylinder
212
and/or in the process of passage through the slits
214
provided in cylinder
212
, be exhausted to the downstream side of pyrolysis means
203
.
If necessary, a trapping means, which recovers decomposition products contained in the above mentioned decomposition gas by adsorption or reaction, may be provided between gas exhausting means
205
and the above-described pyrolysis means
203
.
(Third Embodiment)
A second mode of the above-described pyrolysis means
203
and gas introduction means
202
shall now be described with reference to FIG.
12
.
Parts that are in common to those of gaseous organohalogen compound decomposition treatment device
201
of the above-described second embodiment shall be provided with the same symbols and descriptions thereof shall be omitted.
A gaseous organohalogen compound decomposition treatment device
220
, which is a third embodiment of this invention, comprises a gas introduction means
202
a
, pyrolysis means
203
a
, and a heating means
204
as the principal components, and is furthermore equipped with a gas exhausting means
205
(not shown) at the downstream side.
Here, the heating means
204
and gas exhausting means
205
(not shown) of this gaseous organohalogen compound decomposition treatment device
220
are the same in arrangement as those of the above-described gaseous organohalogen compound decomposition treatment device
201
, and thus descriptions thereof shall be omitted. The heating unit of pyrolysis means
203
a
of the present gaseous organohalogen compound decomposition treatment device
220
is a cylinder
222
, which is sealed at both ends (see FIG.
12
).
Inside this cylinder
222
, a circular pipe
223
, which is the gas introduction means
202
a
, is passed through from one end face towards the other end face.
A plurality of exhaust holes
224
are provided on the outer circumferential surface at parts of circular pipe
223
that are positioned inside the above mentioned cylinder
222
. A plurality of slits
214
, which put the interior and exterior of cylinder
222
in communication, are provided on the outer circumferential surface of cylinder
222
through which circular pipe
223
is inserted. The downstream end of circular pipe
223
is sealed.
The treated gas that is supplied to this heating unit is thus supplied into the above mentioned cylinder
222
from the exhaust holes
224
provided on the outer circumferential surface of the above mentioned circular pipe
223
. The treated gas that has been supplied into this cylinder
222
is then exhausted to the exterior of cylinder
222
upon passage through the slits
214
that are provided on the outer circumferential surface of cylinder
222
.
Here, since cylinder
222
is heated by heating means
204
, the treated gas that has been guided inside cylinder
222
is decomposed by contact with the inner wall surface of the heated cylinder
222
in the process of moving inside cylinder
222
towards the side of the above mentioned slits
214
. Also, even if the treated gas does not contact the inner wall surface of cylinder
222
, it is pyrolyzed by radiant heat in the process of passage through the slits
214
that are provided in cylinder
222
.
Treated gas will thus not be exhausted from the slits
214
of cylinder
222
but only the decomposition gas that has been decomposed to a harmless state is exhausted and the decomposition treatment of the treated gas is thus accomplished.
Here, the diameter and material of cylinder
222
and the number and slit width of slits
214
may be determined as suited in the same manner as in the first embodiment.
Furthermore, a rifling
217
may be provided on the inner wall surface of cylinder
222
in order to perform efficient stirring of the treated gas.
Also, with regard to the positional relationship of the exhaust holes
224
provided in the above mentioned circular pipe
223
and the slits
214
provided in cylinder
222
, exhaust holes
224
and slits
214
are preferably shifted with respect to each other so that the treated gas that is exhausted from the above mentioned exhaust holes
224
will not be exhausted directly from slits
214
. With the present embodiment, slits
214
are provided at positions shifted by 90° with respect to exhaust holes
224
(see FIG.
12
B).
A fourth embodiment of the above-described pyrolysis means
203
and gas introduction means
202
shall now be described with reference to FIG.
13
.
A gaseous organohalogen compound decomposition treatment device
230
, which is a fourth embodiment of this invention, comprises a gas introduction means
202
b
, pyrolysis means
203
b
, and a heating means
204
as the principal components, and is furthermore equipped with a gas exhausting means
205
(not shown) at the downstream side.
Here, the heating means
204
and gas exhausting means
205
are the same in arrangement as those of the above-described gaseous organohalogen compound decomposition treatment device
201
, and thus descriptions thereof shall be omitted.
The gas introduction means
202
b
and pyrolysis means
203
b
of this gaseous organohalogen compound decomposition treatment device
230
are respectively housed inside a casing
231
.
This casing
231
comprises a cylindrical outer cylinder part
232
and lids
233
, which are screwed onto the ends of outer cylinder part
232
by means of screws
234
.
Inside this casing
231
, an alumina chamber
235
with a cylindrical shape is housed in a manner whereby it is clamped by the above mentioned lids
233
via O-rings
236
that are provided at both ends.
A circular pipe
202
b
, for introducing the treated gas inside this gaseous organohalogen compound decomposition treatment device
230
, is inserted into the upstream side of casing
231
, and the tip of this circular pipe
202
b
is fitted into an indented part
238
of an upstream side protrusion
237
that is protruded inwards at the upstream side of the above mentioned alumina chamber
235
.
Meanwhile at the downstream side of this casing
231
is inserted an exhaust pipe
239
, which exhausts, from casing
231
, the decomposition gas resulting from the decomposition of the treated gas, and the tip of this exhaust pipe
239
is fitted into an indented part
241
of a downstream side protrusion
240
that is protruded inwards at the downstream side of the above mentioned alumina chamber
235
.
Between the upstream side protrusion
237
and downstream side protrusion
240
of the above mentioned alumina chamber
235
, a cylinder
242
, which is the pyrolysis means
203
b
, is clamped by the upstream side protrusion
237
and downstream side protrusion
240
. Inside this cylinder
242
is provided a partition wall
243
, which partitions the space inside this cylinder
242
into an upstream side hollow part
244
and a downstream side hollow part
245
.
Slits
214
a
and slits
214
b
, which put the interior and exterior of cylinder
242
in communication, are provided in plurality on the outer peripheral surfaces of cylinder
242
at positions corresponding to upstream side hollow part
244
and downstream side hollow part
245
, respectively.
A communicating space
246
, which puts the above mentioned upstream side hollow part
244
and the downstream side hollow part
245
in communication, is formed between the part surrounded by the upstream side protrusion
237
and downstream side protrusion
240
of the above mentioned alumina chamber
235
and the outer peripheral surface of cylinder
242
.
Here, cylinder
242
is induction heated by a high-frequency coil
215
of the above mentioned heating means
204
and a flow of gas from the upstream side to the downstream side of cylinder
242
is caused by the gas exhausting means
205
(not shown).
The treated gas, which has been introduced inside this gaseous organohalogen compound decomposition treatment device
230
through circular pipe
202
b
, is first subject to contact pyrolysis by contact with the inner wall of upstream side hollow part
244
and partition wall
243
of cylinder
242
and is then pyrolyzed by radiant heat in the process of being guided into communicating space
246
upon passage through the slits
214
a
provided at the upstream side hollow part
244
.
The treated gas is then passed from the interior of communicating space
246
, through slits
214
b
, and into the downstream side hollow part
245
.
Thus even if undecomposed treated gas is contained in the gas that is guided from the above mentioned upstream side hollow part
244
into this communicating space
246
, this undecomposed treated gas will have the opportunity of being subject again to pyrolysis by radiant heat and contact pyrolysis by contact with the inner wall surface of downstream side hollow part
245
.
As a result, the gas resulting from the gasification of halogen compounds is decomposed into harmless decomposition gas without fail.
At the outer circumferential surface parts of the above-described guiding pipe
202
b
at positions housed inside the above mentioned alumina chamber
235
are provided communicating holes
247
for putting the interior and exterior of guide pipe
202
b
in communication. Furthermore, exhaust holes
248
, which put the interior and exterior of the above mentioned alumina chamber
235
in communication, are provided at the upstream side of alumina chamber
235
.
Thus when a flow of gas from the upstream side to the downstream side of this gaseous organohalogen compound decomposition treatment device
230
is caused by operation of a vacuum pump (not shown) of a pressure reducing means
4
that is positioned at the downstream side of gaseous organohalogen compound decomposition treatment device
230
, the gas inside a space
249
between the outer circumferential surface of alumina chamber
235
and housing
231
is sucked in and the interior of space
249
is kept under a reduced pressure atmosphere.
Since high-frequency coil
215
of heating means
204
is housed inside this space
249
, the maintaining of the interior of this space
249
under a reduced pressure atmosphere leads to the prevention of the degradation of the high-frequency coil
215
by oxidation.
Also, since the interior of space
249
is kept under a reduced pressure atmosphere, the heat that is applied to the above mentioned pyrolysis means
203
b
that is heated by high-frequency coil
215
will also not be emitted to the exterior of casing
231
by heat transfer. All heat can thus be used to heat cylinder
242
of the above-described pyrolysis means
203
b
without giving rise to heat loss.
A liquid organohalogen compound decomposition treatment device
250
, which applies this invention's gaseous organohalogen compound decomposition treatment device shall now be described.
FIG. 14
is a schematic arrangement diagram of liquid organohalogen compound decomposition treatment device
250
, which applies this invention's gaseous organohalogen compound decomposition treatment device.
This liquid organohalogen compound decomposition treatment device
250
comprises a storage means
251
, discharge means
252
, gasifying means
253
, decomposition treatment means
254
, trapping means
255
, and pressure reducing means
256
as the principal components.
The storage means
251
of this liquid organohalogen compound decomposition treatment device
250
stores liquid PCBs.
This storage means
251
comprises a slide gate valve
260
, a first storage tank
261
, and a second storage tank
262
.
The slide gate valve
260
of this storage means
251
is interposed between the above mentioned first storage tank
261
and a funnel-shaped loading entrance
263
, and after the loading of liquid PCBs into first storage tank
261
has been completed, slide gate valve
260
is closed to prevent the mixing of excess air into first storage tank
261
.
First storage tank
261
is disposed at the lower side of the above mentioned slide gate valve
260
and stores the liquid PCBs that have been loaded via the above mentioned slide gate valve
260
.
Second storage tank
262
is disposed at the lower side of the above mentioned first storage tank
261
with a supply valve
264
provided in between and stores the liquid PCBs discharged from the above mentioned first storage tank
261
under a reduced pressure atmosphere.
The reduced pressure atmosphere inside this second storage tank
262
is formed by a vacuum pump
293
, of the below-described pressure reducing means
256
, that exhausts the air, which has been guided into second storage tank
262
along with the liquid PCBs in the process of supplying the liquid PCBs, via an evacuation piping
265
provided at an upper part of second storage tank
262
.
Also, the opening and closing of the supply valve
264
interposed between first storage tank
261
and second storage tank
262
is performed as suited based on detection results obtained by detection of the amount of liquid PCBs stored in second storage tank
262
by means of upper limit liquid level sensor
266
and lower limit liquid level sensor
267
provided inside second storage tank
262
.
Likewise, the opening and closing of the above mentioned slide gate valve
260
is performed as suited based on the detection result of a liquid level sensor
268
provided inside the above mentioned first storage tank
261
.
Storage means
251
thus prevents the lowering of the degree of reduced pressure inside the liquid organohalogen compound decomposition treatment device
250
due to the mixing in of air into the downstream side of storage means
251
(the parts from gasifying means
253
to trapping means
255
) in the process of decomposition treatment of liquid PCBs. That is, a structure with which the atmospheric system and a reduced pressure system are sealed by a liquid is formed.
The discharge means
252
of this liquid organohalogen compound decomposition treatment device
250
supplies a predetermined amount at a time of the liquid PCBs stored in second storage tank
262
of the above-described storage means
251
into a liquid supply pipe
270
of the gasifying means
253
to be described later.
Here with the present embodiment, a needle valve
269
is used as this discharge means
252
.
With this needle valve
269
, the degree of opening of needle valve
269
is determined based on the measurement value, etc., of a pressure sensor
277
, provided inside a treatment chamber
273
of the below-described gasifying means
253
, to drip the liquid PCBs into liquid supply pipe
270
of the below-described gasifying means
253
at a predetermined rate and amount.
Thus by the existence of this discharge means
252
, an amount of liquid PCBs that is optimal for the gasification of liquid PCBs inside the below-described gasifying means
253
is supplied at all times.
The gasifying means
253
of this liquid organohalogen compound decomposition treatment device
250
is a device that heats the liquid PCBs that are supplied via the above-described discharge means
252
from within the above-described storage means
251
and thereby gasifies the liquid PCBs to gaseous PCBs (see FIG.
11
).
This gasifying means
253
comprises a liquid supply pipe
270
, gasification cylinder
271
, heating part
272
, and treatment chamber
273
.
The liquid supply pipe
270
of gasifying means
253
introduces the liquid PCBs, which have been discharged from the above-described storage means
251
by the above-described discharge means
252
, into gasification cylinder
271
of gasifying means
253
.
With the present embodiment, a circular pipe is used as this liquid supply pipe
270
and the upper end of liquid supply pipe
270
is connected to the discharge port (not shown) of the above-described discharge means
252
, the lower end is inserted into gasification cylinder
271
, and the tip of this liquid supply pipe
270
extends to the lower part of the interior of gasification cylinder
271
.
In order to prevent detachment from the above-described discharge means
252
due to expansion and shrinkage by heating and cooling and to prevent breakage of liquid supply pipe
270
, liquid supply pipe
270
is arranged from alumina, which is excellent in heat resistant and low in expansion and shrinkage due to heat.
This liquid supply pipe
270
is constantly heated to a high temperature by the heating part
272
to be described later and is constantly placed under a reduced pressure atmosphere by the operation of vacuum pump
293
, which is the below-described pressure reducing means
256
of this liquid organohalogen compound decomposition treatment device
250
.
The liquid PCBs that has been dripped or sprayed into liquid supply pipe
270
is heated in the process of falling freely from the upper part to lower part of the interior of liquid supply pipe
270
and most of the liquid PCBs is thus converted to gaseous PCBs.
Since the air inside treatment chamber
273
, in which liquid supply pipe
270
is housed, is constantly drawn by vacuum pump
293
of the below-described pressure reducing means
256
, the gaseous PCBs and liquid PCBs are sucked out towards the inner side of gasifying cylinder
271
into which liquid supply pipe
270
is inserted.
This gasifying cylinder
271
of gasifying means
253
exposes the liquid PCBs and gaseous PCBs supplied via the above-described liquid supply pipe
270
to a heated environment and thereby gasifies all of the PCBs to gaseous PCBs.
This gasifying cylinder
271
has the shape of a cylinder with both ends closed and the above-described liquid supply pipe
270
is inserted from the one end side at the upper side (see FIG.
11
).
This gasifying cylinder
271
is set on the upper surface of an alumina pedestal
274
, which is disposed inside the treatment chamber
273
that houses gasifying cylinder
271
, and on the outer peripheral surface of gasifying cylinder
271
, a plurality of slits
275
, which put the interior and exterior of gasifying cylinder
271
in communication, are provided along the circumferential direction from the central part to upper part of gasifying cylinder
271
.
As with the above-described liquid supply pipe
270
, gasifying cylinder
271
is also heated by the heating part
272
to be described later. The gaseous PCBs that have been sucked out from the above-described liquid supply pipe
270
are thus decomposed by heat upon contact with the inner wall surface of gasifying pipe
271
. Meanwhile, even if gaseous PCBs are guided to slits
275
without contacting the inner wall surface of the gasifying part, the gaseous PCBs will be decomposed by heat in the process of passage through the slits
275
.
However, since the present embodiment is arranged to gasify liquid PCBs at the above-described liquid supply pipe
270
and gasifying cylinder
271
, the heat inside liquid supply pipe
270
and gasifying pipe
271
is taken up when the liquid PCBs are gasified.
The existence of gaseous PCBs that are lead to the downstream side of gasifying means
253
without being decomposed inside gasifying cylinder
271
may thus be of concern. Thus with this embodiment's liquid organohalogen compound decomposition treatment device
250
, the above-described gaseous organohalogen compound decomposition treatment device
201
is disposed as the decomposition treatment means
254
at the downstream side of gasifying means
253
in order to assure complete decomposition treatment of the gaseous PCBs.
The heating part
272
of gasifying means
253
heats liquid supply pipe
270
and gasifying cylinder
271
.
Heating part
272
comprises a high-frequency coil
276
. This high-frequency coil
276
is disposed at a position separated from the outer circumferential surfaces of the above-described liquid supply pipe
270
and gasifying cylinder
271
in a manner whereby it spirals downward from the upper side. High-frequency coil
276
is connected to an unillustrated high-frequency power supply and heats gasifying cylinder
271
and liquid supply pipe
270
as suited to a desired temperature.
The treatment chamber
273
of gasifying means
253
houses liquid supply pipe
270
, gasifying cylinder
271
, and heating part
272
. The interior of this treatment chamber
273
is maintained constantly under a reduced pressure atmosphere by vacuum pump
293
of the below-described pressure reducing means
256
.
Treatment chamber
273
is equipped with a pressure sensor
277
, which measures the pressure inside treatment chamber
273
, and a rupture disc
300
, which functions as a pressure release valve
278
.
This pressure release valve
278
opens to release the pressure inside treatment chamber
273
when a large amount of gas that exceeds the evacuation capacity of vacuum pump
293
of the below-described pressure reducing means
256
is generated in treatment chamber
273
and the interior of treatment chamber
273
is put in a pressurized state.
When the pressure inside treatment chamber
273
is released by pressure release valve
278
, the gaseous PCBs inside treatment chamber
273
will be released into the atmosphere. Thus in order to prevent the release of PCBs into the atmosphere, a trap
303
, which is shown in
FIG. 16
, is preferably provided.
This trap device is connected via a piping
301
to the above-described treatment chamber
273
and a vacuum pump
304
, which creates a reduced pressure environment inside the trap via a valve, is provided at the downstream side of the trap.
Since the interior of trap
303
is constantly maintained in a reduced pressure state by vacuum pump
304
, when the pressure release valve
278
of the above-described treatment chamber
273
is opened, pressure is absorbed within the space extending from piping
301
to trap
303
.
A cooling pipe
302
, through which liquid nitrogen or other suitable coolant is passed through, is provided inside trap
303
and on the outer peripheral surface of piping
301
. This cooling pipe
302
is disposed in a meandering manner inside trap
303
and is provided with fins, for efficient cooling of the interior of trap
303
, on the outer peripheral surface of the part of cooling pipe
302
that is positioned inside trap
303
.
Thus by passing a coolant through cooling pipe
302
, the high-temperature gas that is discharged from within the above-described treatment chamber
273
is cooled rapidly and the volume of the gas is reduced. As a result, the breakage of trap
303
and piping
301
is prevented and the discharge of PCBs outside the device is prevented.
The decomposition treatment means
254
of liquid organohalogen compound decomposition treatment device
250
is connected to the downstream side of treatment chamber
273
of the above-described gasifying means
253
and pyrolyzes the gasified gas of PCBs that is discharged from the aforementioned treatment chamber.
This treatment means
54
is the same in arrangement as the above-described gaseous organohalogen compound decomposition treatment device
201
and a description thereof shall thereof be omitted here.
The trapping means
255
of this liquid organohalogen compound decomposition treatment device
250
recovers the decomposition products contained in the decomposition gas resulting from the decomposition of gaseous PCBs in the above-described decomposition treatment means
254
.
This trapping means
255
is connected to the downstream side of the above-described decomposition treatment means
254
and comprises an upper chamber
281
, which is equipped with a cooling plate
280
, and a lower chamber
282
, which is connected via a gate valve
283
to the lower side of upper chamber
281
.
The cooling plate
280
provided at upper chamber
281
is arranged from nickel alloy and adsorbs the high-temperature decomposition gas, which has been guided into trapping means
255
, as carbon content using the catalytic reaction of nickel and prevents the high-temperature decomposition gas from being supplied directly into pressure reducing means
256
, which is disposed at the downstream side of this trapping means
255
.
The above-described cooling plate
280
is connected to an unillustrated cooling pipe and is constantly cooled to a low temperature by liquid nitrogen or other coolant that is passed through this cooling pipe. The high-temperature decomposition gas that is discharged from the decomposition treatment means
254
upstream the trapping means
255
is thereby cooled rapidly to promote the adsorption of decomposition products in the decomposition gas.
The method of configuring this cooling plate
280
is not restricted in particular as long as the configuration is such that the atmosphere inside upper chamber
281
will be guided to pressure reducing means
256
at the downstream side after passing through the gap between cooling plate
280
and upper chamber
281
.
Lower chamber
282
is a device for recovering the decomposition products that have been adsorbed and trapped within upper chamber
281
. An inert gas cylinder (not shown) for replacing the interior of lower chamber
282
with argon or other inert gas and a vacuum pump
287
are thus connected via inert gas supply piping
284
and evacuation piping
285
to the interior of lower chamber
282
.
Thus by closing the gate valve
283
, which partitions lower chamber
282
and upper chamber
281
and then supplying inert gas via the inert gas supply piping
284
that is connected to lower chamber
282
to bring the pressure inside lower chamber
282
to atmospheric pressure, carbon and other decomposition products that have been stored in lower chamber
282
can be recovered from carbon powder take-out exit
286
.
Then after removing the carbon powder from lower chamber
282
and then bringing the interior of lower chamber
282
back to a reduced pressure atmosphere by means of the vacuum pump
287
that is connected to lower chamber
282
, the above mentioned gate valve
283
is opened to put lower chamber
282
into communication with the above-described upper chamber
281
to enable carbon and other decomposition products to be stored in lower chamber
282
again.
The work of removing the carbon powder, etc., can thus be performed without stopping this invention's liquid organohalogen compound decomposition treatment device
250
.
Also in place of the above-described cooling plate
280
, a cage
291
, filled with nickel balls
290
, may be provided and the decomposition gas that is discharged from the above-described decomposition treatment means
254
may be passed through the interior of this cage
291
and then discharged from the downstream side of this trapping means
255
(see FIG.
15
).
With this embodiment, nickel balls
290
, which have been cooled by a suitable cooling means, are arranged to be dropped intermittently downwards from the upper side of cage
291
. In this case, the decomposition gas that passes through cage
291
becomes attached to the surfaces of nickel balls
290
as carbon, etc., by the catalytic action of nickel.
And by the shaking by a vibrating screen
292
, disposed at the lower side of cage
291
, the carbon, etc., that have become attached to the surfaces of nickel balls
290
are removed and recovered inside the above-described lower chamber
282
.
The nickel balls
290
from which carbon, etc., have been removed are circulated and supplied again to cage
291
.
The pressure reducing means
256
of this invention's liquid organohalogen compound decomposition treatment device
250
forcibly discharges the atmosphere inside second storage tank
262
of the above-described storage means
251
, treatment chamber
273
of the above-described gasifying means
253
, and the above-described trapping means
255
out of the device and forms a reduced pressure atmosphere inside this invention's liquid organohalogen compound decomposition treatment device
250
.
With the present embodiment, a vacuum pump
293
is used as this pressure reducing means
256
. As with the above-described gaseous organohalogen compound decomposition treatment device
201
, a vacuum pump that is generally used in the present field is used as vacuum pump
293
.
As shown in
FIG. 17
, an arrangement is also possible wherein the decomposition treatment means
254
, trapping means
255
, and pressure reducing means
256
are connected further via the piping of this pressure reducing means
256
as shown in FIG.
17
.
By this arrangement, when a problem occurs at any part between gasifying means
253
and trapping means of liquid organohalogen compound decomposition treatment device
250
, the undecomposed PCB's that resides at the part between gasifying means
253
and trapping means
255
can be rendered harmless.
<Operation>
The operation of this invention's liquid organohalogen compound decomposition treatment device
250
shall now be described.
First, the slide gate valve
260
of the above-described storage means
251
is opened to load liquid organohalogen compounds into first storage tank
261
, and after completion of loading, slide gate valve
260
is closed.
Subsequently, supply valve
264
is opened to transfer the liquid organohalogen compounds inside the above-described first storage tank
261
to second storage tank
262
. The valve
279
of the evacuation piping
265
that is connected to the upper face of this second storage tank
262
is opened and the air inside second storage tank
262
is discharged by vacuum pump
293
to form a reduced pressure atmosphere inside second storage tank
262
.
The needle valve
279
, mounted to the lower side of second storage tank
262
, is opened and the liquid organohalogen compounds stored inside second storage tank
262
are dripped into liquid supply pipe
270
of gasifying means
253
.
The liquid organohalogen compounds that are dripped into liquid supply pipe
270
are heated and gasified as they drop through the interior of liquid supply pipe
270
and most of the compounds are converted to gaseous organohalogen compounds.
The liquid organohalogen compounds that are not gasified inside liquid supply pipe
270
are heated and gasified completely inside the gasifying cylinder
271
in which the tip part of liquid supply pipe
270
is housed.
The gaseous organohalogen compounds that were generated inside this gasifying means
253
are drawn out towards the decomposition treatment means
254
at the downstream side by vacuum pump
293
of pressure reducing means
256
and then passed through the interior of circular pipe
210
of decomposition treatment means
254
and guided to cylinder
212
(see FIGS.
11
through
14
).
The gaseous organohalogen compounds that have been guided into cylinder
212
are guided to the slits
214
provided on the outer circumferential surface of cylinder
212
while being stirred in spiraling manner by rifling
217
inside cylinder
212
.
In this process, the gaseous organohalogen compounds that contact the inner wall surface of cylinder
212
are contact pyrolyzed by heat and converted into decomposition gas. The gaseous organohalogen compounds that did not make contact are decomposed to decomposition gas by radiant heat in the process of passage through slits
214
.
When the decomposition gas that is then guided to the trapping means
255
, positioned downstream the decomposition treatment means
254
, contacts the cooled nickel cooling plate
280
inside trapping means
255
, the decomposition gas becomes adsorbed and recovered as soot on cooling plate
280
due to the catalytic action of nickel.
(Fifth Embodiment)
An embodiment of an organohalogen compound pyrolysis treatment device by this invention shall now be described with reference to the attached drawings.
As shown in
FIG. 18
, an organohalogen compound pyrolysis treatment device
401
by this invention comprises an introduction part
402
, into which dioxin-containing gas is introduced, a pyrolysis part
403
, which pyrolyzes the dioxin-containing gas that has been introduced into the above mentioned introduction part
402
, a discharge part
404
, which discharges the pyrolysis gas resulting from the decomposition at the above mentioned pyrolysis part
403
, and an induction heating coil
405
, which surrounds the main body
403
a
of the above mentioned pyrolysis part
403
from the exterior and heats a heating unit
403
f
in the interior, as the principal components.
Introduction part
402
comprises a dioxin-containing gas introduction entrance
402
a
and a duct
402
b
, which becomes enlarged in diameter from the upstream side to the downstream side, as the principal components.
A water-cooled type cooling jacket
402
c
for cooling introduction part
402
is provided at the outer circumference of duct
402
b.
A flange
402
d
is provided at the large-diameter end of duct
402
b
and is joined by a plurality of sets of bolts B and nuts N to a flange
403
b
provided at an end of the below-described pyrolysis part
403
.
At the interior of duct
402
b
is provided a guide member
403
e
, which, as shown in
FIG. 19
, protrudes towards the upstream side from the central part of a pipe supporting plate
403
c
of pyrolysis part
403
to enable the dioxin-containing gas to be introduced readily into ceramic pipes
403
d
. Though guide member
403
e
has a conical shape in the present embodiment, other embodiments shall be described later.
As shown in
FIG. 19
, pyrolysis part
403
mainly comprises a cylindrical main body
403
a
, a heating unit
403
f
, which is disposed substantially at the center of the interior of the above mentioned main body
403
a
and has eight through holes
403
h
that are positioned in the radial direction and along the inner side of the outer circumference, a plurality of ceramic pipes
403
d
, which are inserted through the eight through holes
403
h
of the above mentioned heating unit
403
f
, pipe supporting plates
403
c
and
403
g
, which respectively support the respective ends of the above mentioned ceramic pipes
403
d
, and spacers
403
k
and
403
l
, which are for positioning the above mentioned heating unit
403
f
in the above mentioned pyrolysis part
403
.
Main body
403
a
is a cylindrical container made of alumina. As shown in
FIG. 18
, at the outer circumferential surface of main body
403
a
, induction heating coil
405
for heating the heating unit
403
f
is provided in a surrounding manner.
Though with the present embodiment, alumina is used as the material of main body
403
a
, a non-dielectric ceramic, such as silica and SiC, may be used as a material besides alumina.
To the main body
403
a
of the present embodiment is mounted a single nozzle
403
al
for connecting the interior of main body
403
a
via a piping to a pressure reducing means, for example, a vacuum pump (see FIGS.
18
and
19
).
By thus arranging main body
403
a
to be connected to a pressure reducing means, the interior of main body
403
a
can be reduced in pressure by means of the pressure reducing means to lessen the amount of oxygen in the air in the process of performing induction heating of the heating unit, and since the amount of consumption of the carbon or other combusting component that makes up heating unit
403
f
can thus be lessened, the life of heating unit
403
a f
can be elongated.
As another method, another single nozzle
403
al
may be provided separately, the two nozzles may be used as an entrance and exit, respectively, for a gas, nozzle
403
al
may be connected to an inert gas pressurizing means, for example, a gas cylinder, and induction heating may be performed after replacing the interior of main body
403
a
with inert gas. Since there will thus be no oxygen in the air, the life of heating unit
403
a f
can be elongated.
With regard to the inert gas, since nitrogen and carbon dioxide produce nitrogen compounds and carbon compounds with ceramic materials at high temperatures, replacement by argon gas or helium gas is preferable.
As the material of heating unit
403
a f
, clay carbon, with the same cylindrical shape as a briquette, is used in the present embodiment as shown in FIG.
19
. Heating unit
403
a f
is provided with eight through holes
403
h
that are positioned in the radial direction and along the inner side of the outer circumference.
By providing eight through holes
403
h
in the radial direction and along the inner side of the outer circumference of the heating unit, since heating unit
403
a f
is heated from the outer side to the inner side when heating unit
403
a f
is induction heated, the dioxin-containing gas can be made to flow immediately through the eight through holes
403
h.
Though a material, such as a dielectric ceramic, etc., may be used as the material of heating unit
403
a f
, the use of a carbon material, such as graphite, etc., is more preferable in that the rate of temperature rise in the heating process can be made high.
Though besides a cylindrical shape, a quadratic prism shape may be used as the shape of heating unit
403
a f
, the electric current will concentrate at the corner parts and the temperature distribution will tend to be non-uniform with a quadratic prism.
A non-dielectric material, for example, a circular pipe of alumina is used as ceramic pipe
403
d
. Silicon carbide can also be given as a material that may be used besides alumina.
Ceramic pipes
403
d
are inserted through the eight through holes
403
h
provided in heating unit
403
a f
and the ends at both sides are supported by through holes
403
H
1
and
403
H
2
of the two pipe supporting plates
403
c
and
403
g
. Also, by reducing the cross-sectional area of the gas flow path inside duct
402
b
by means of guide member
403
e
and making the flow rate higher, the clogging of the interiors of ceramic pipes
403
d
by uncombusted carbon and other solids can be prevented even if such solids are contained in the dioxin-containing gas.
Pipe supporting plates
403
c
and
403
g
are disk-shaped plates made of a metal, such as alumina, and respectively have eight through holes
403
H
1
and
403
H
2
formed in the radial direction and along the inner sides of the outer circumferences. Guide member
403
e
and
403
i
, which distribute and guide the dioxin-containing gas into the respective ceramic pipes
403
d
are provided as conical protrusions at the central parts of pipe supporting plates
403
c
and
403
g
, respectively.
By providing such conical protrusions and varying the cross-sectional area of the flow path, the introduction and discharge of the dioxin-containing gas and pyrolysis gas can be performed favorably inside ducts
402
b
and
404
b.
With regard to the mounting position, guide member
403
i
is mounted at the upstream side of pipe supporting plate
403
c
at introduction part
402
and is mounted to the downstream side of pipe supporting plate
403
g
at discharge part
404
. The guide member
403
i
at the discharge part
404
side may be omitted.
Spacers
403
k
and
403
l
comprise cylindrical pipes
403
k
1
and
403
l
1
, respectively, which are cylindrical members, and flanges
403
k
2 and 403
l
2
, respectively, and the open end parts of the above mentioned pipes
403
k
1
and
403
l
1
are formed so that the inner surfaces of the open end parts fit in a detachable manner with step parts
403
a f
1
and
403
a f
2
provided at both ends of the above-described heating unit
403
a f
to thereby enable supporting of the heating unit
403
a f
at the fitted parts.
Each of flanges
403
k
1
, and
403
l
1
, is provided with eight through holes (
403
kh
), (
403
lh
) for insertion of the ceramic pipes.
By supporting both ends of heating unit
403
a f
by the two spacers
403
k
and
403
l
at both sides, the position of heating unit
403
a f
in pyrolysis part
403
can be fixed substantially at the center of main body
403
a
at all times. As a result, the position to be heated by induction heating coil
405
can always be set to the central part of heating unit
403
a f
, and the temperature inside ceramic pipes
403
d
will thus be prevented from varying greatly due to the shifting of the position at which heating unit
403
a f
is heated.
With the present embodiment, a non-dielectric material, such as aluminum, is used as the material of spacers
403
k
and
403
l.
Discharge part
404
mainly comprises a dioxin pyrolysis gas discharge port
404
a
and a duct
404
b
, which decreases in diameter from the upstream side to the downstream side.
As with introduction part
402
, a water-cooled type cooling jacket
404
c
for cooling the duct
404
b
is provided on the outer circumference of duct
404
b
as shown in FIG.
18
.
A flange
4
d
is provided at the large-diameter end of duct
404
b
and is joined by bolts B and nuts N to a flange
3
j
provided at an end of pyrolysis part
403
.
At the interior of duct
404
b
is provided a guide member
403
i
, which protrudes towards the downstream side from the central part of pipe supporting plate
403
g
of pyrolysis part
403
to enable the pyrolysis gas, resulting from the pyrolysis of the dioxin-containing gas at pyrolysis part
403
, to be discharged readily from ceramic pipes
403
d.
The actions of this invention's organohalogen compound pyrolysis treatment device with the above arrangement shall now be described with reference to FIG.
20
. With
FIG. 20
, part of the components shown in
FIGS. 18 and 19
are illustrated in simplified form for ease of comprehension.
(1) Cooling water is made to flow through and power is supplied to induction heating coil
405
to heat the heating unit
403
a f
housed inside pyrolysis part
403
.
(2) Heating unit
403
a f
is heated, the heat of heating unit
403
a f
is heat transferred to ceramic pipes
403
d
, and in a few seconds, ceramic pipes
403
d
are raised in temperature to a predetermined temperature, for example, 1400° C.
(3) The dioxin-containing gas is introduced into duct
402
b
via introduction entrance
402
a
of introduction part
402
.
(4) The dioxin-containing gas that has been introduced receives a shear force due to the conical guide member
403
e
provided inside duct
402
b
, is thereby accelerated along the slope of the cone, and is distributed and guided into the eight ceramic pipes
403
d
, which are inserted respectively in the eight through holes
403
H
1
of the cylindrical heating unit
403
a f
and have the ends at both sides fixed by pipe supporting plates
403
c
and
403
g.
(5) The dioxin-containing gas that has been introduced into the respective ceramic pipes
403
d
is pyrolyzed favorably by contact with the inner wall surfaces of the ceramic pipes
403
d
that have been heated to 1400° C.
(6) The pyrolyzed gas is discharged to discharge part
404
. In this process, the pyrolysis gas is discharged favorably from inside the eight ceramic pipes
403
d
to discharge port
404
a
by means of the guide member
403
i
provided inside duct
404
b
of discharge part
404
.
(7) The dioxin pyrolysis gas that is discharged from discharge port
404
a
is treated at a downstream stage by a gas cleaning equipment for elimination of halogen gas, NO
x
, etc. and is discharged to the atmosphere upon elimination of components that are harmful to the human body.
For example, a wet type alkali cleaning equipment or a dry type adsorption device may be used as the above mentioned gas cleaning equipment.
Though the above-described guide members
403
e
and
403
i
had conical shapes in the present embodiment, other embodiments shall now be described with reference to FIG.
21
.
Guide member
406
e
of a first other embodiment has a plurality of grooves GT provided along the slope of the cone from the apex of the cone as shown in
FIG. 21A
in order to further facilitate the introduction of the dioxin-containing gas into the interiors of the ceramic pipes in comparison to a conical guide member. Each grooves GT is preferably provided with a shape such that the width of groove GT expands from the apex of the cone towards the bottom side of the cone.
By thus providing such a gas guide member
406
e
, provided with a plurality of grooves GT along the slope of a cone, inside the duct of the introduction part, the cross-sectional area of the flow path of the gas inside the duct is made gradually smaller towards the downstream side and pressure energy is thus converted to the speed energy of the gas. And by the pushing of the gas into the ceramic pipes along the grooves GT, the gas can be distributed favorably and the gas can be made to flow through the ceramic pipes at a high gas flow rate.
A dome-shaped protrusion may be provided as with guide member
407
e
of a second other embodiment, shown in FIG.
21
B. The protrusion may for example have the shape of a 2:1 ellipse mirror plate or dish, etc.
By forming guide member
407
e
in this manner, the dioxin-containing gas can be introduced more readily into the interiors of the ceramic pipes.
EXAMPLES
A method of treating organohalogen compounds and/or substances containing organohalogen compounds, in other words, PCBs and/or PCBs-containing substances using this invention's organohalogen compound decomposition treatment device
1
shall now be described with reference to
FIG. 3
or
4
as suited.
A capacitor containing PCBs is housed inside heating container
12
. This heating container
12
is carried into lower chamber
10
from the carry-in entrance
15
that is provided at lower chamber
10
of gasifying means
2
and is set on the alumina pedestal
18
on lift
17
inside lower chamber
10
(see FIG.
4
).
After closing the above mentioned carry-in entrance
15
, valve
22
at the downstream side of vacuum exhaust pipe
20
is opened, the interior of lower chamber
10
is decompressed by means of vacuum pump
42
, and the pressure inside lower chamber
10
is thereby made 100 Pa (gauge pressure) or less (see FIG.
3
).
Thereafter, valve
22
is closed, valve
23
, which is interposed between a nitrogen gas cylinder and inert gas introduction pipe
21
, is opened to introduce nitrogen gas into lower chamber
10
, and after nitrogen replacement has been accomplished, valve
23
is closed. This series of pressure reduction—nitrogen replacement operations is repeated twice.
After completion of the nitrogen replacement of the interior of lower chamber
10
, shutter
14
is opened to put upper chamber
11
, which is constantly maintained in a reduced pressure state by means of vacuum pump
42
, and lower chamber
10
, which has been subject to nitrogen replacement, into communication. Lift
17
is then raised to send out the heating container
12
, in which the treated object P is contained, and make the container be housed in the inner side of high-frequency coil
24
provided inside upper chamber
11
. Lift
17
is then made to contact the roof surface of lower chamber
10
to thereby seal the interior of upper chamber
11
(see FIG.
4
).
Vacuum valve
46
and butterfly valve
45
are closed and liquid nitrogen is made to flow through cooling pipe
48
to actuate the pressure differential generating means
5
. The pressure of the isolated space that has been closed by butterfly valve
45
and vacuum valve
46
is made lower than the pressure of the non-isolated space that is not closed to thereby generate a negative pressure state inside the closed, isolated space. Thereafter, butterfly valve
45
is opened gradually and the pressure inside upper chamber
11
of the above-described gasifying means
2
is set to 100 Pa (gauge pressure).
At the same time, heating unit
30
of pyrolysis means
3
is heated and stabilized in temperature at 1400° C. Since in this process the temperature rises due to heating and the pressure inside the space from the above-described gasifying means
2
to the above mentioned butterfly valve
45
increases, the opening of butterfly valve
45
is increased accordingly to adjust the pressure (see FIG.
3
).
When the temperature of heating unit
30
of pyrolysis means
3
stabilizes at 1400° C., the high-frequency power supply of gasifying means
2
is turned on to gradually heat the heating container
12
to thereby heat and melt the treated object P and gasify the PCBs. In this process, the PCBs are gasified while adjusting the opening of butterfly valve
45
so that the pressure inside upper chamber
11
of the PCBs gasifying means
2
is maintained at 100 Pa (gauge pressure).
When upon complete vaporization of the PCBs, the pressure inside upper chamber
11
begins to drop with the opening of butterfly valve
45
being kept fixed, the high-frequency power supply of vaporization means
2
is turned off and heating container
12
is allowed to cool naturally. The power supply of pyrolysis means
3
is also turned off and heating unit
30
is also allowed to cool.
After completion of cooling of heating container
12
, lift
17
is lowered and heating container
12
is moved to lower chamber
10
of gasifying means
2
. Thereafter, shutter
14
is closed to partition upper chamber
11
and lower chamber
10
and the interior of upper chamber
11
is maintained in a reduced pressure state constantly.
Valve
23
is opened and after the interior of lower chamber
10
is brought to atmospheric pressure, heating container
12
is carried out from carry-in entrance
15
and the residues inside heating container
12
are taken out, thereby completing the decomposition treatment of PCBs and/or PCBs-containing substances.
The respective means of this invention's organohalogen compound decomposition treatment device
1
are arranged in blocks and connected via piping.
Since the device can thus be separated into the respective blocks for transport, the device can be transported readily and the installation of the device is also simplified.
Furthermore, an optimal device arrangement can be configured according to the type of treated object by the realignment of the various parts mentioned above, the addition of parts, etc. The configuration of organohalogen compound decomposition treatment device
1
is thus not limited to the above-described arrangements and sequences and may be determined as suited.
Also, the iron chloride that is recovered by the use of this invention's method or device may be used as industrial raw material and the sodium chloride and carbon powder that are recovered are harmless and may thus be used as snow melting agents, etc. Furthermore, since the residue inside the heating container does not contain any organohalogen compounds and other hazardous materials whatsoever, it can be recovered as slag and used in roadbed materials, blocks, etc.
The results of experiment using this invention's gaseous organohalogen compound decomposition treatment device
201
shall now be described.
For the experiment, oil samples of three levels (Sample 1: only electrical insulation oil; Sample 2: electrical insulation oil containing 10 mass % of liquid PCBs; Sample 3: only liquid PCBs) were used.
Here the gasification of each sample was performed inside a chamber adjusted in pressure to 100 Pa or less by the operation of a vacuum pump and performing high-frequency induction heating of a stainless steel container in which each sample was placed.
The decomposition treatment inside the decomposition treatment device was carried out by heating a stainless steel decomposition part to 1000° C. by high-frequency induction heating.
Whether or not the PCBs were decomposed was judged by interposing a dry trap between gaseous organohalogen compound decomposition treatment device
201
and the vacuum pump and using a gas chromatography device to detect whether or not PCBs and dioxins are contained in the activated carbon, which is the filler in the dry trap.
As a result, whereas 0.2 ppm of PCBs were detected with Sample 3 as shown in Table 1 below, most of the PCBs were decomposed. Also with Sample 2, all of the PCBs were decomposed.
TABLE 1
|
|
Material of
Content of
|
decomposition
PCBs in
|
Name of sample
PCBs content (%)
part
activated carbon
|
|
Sample 1
0
Stainless steel
Not detected
|
Sample 2
10
Stainless steel
Not detected
|
Sample 3
100
Stainless steel
0.2 ppm
|
|
It was thus confirmed that this invention's organohalogen compound decomposition device can decompose and render harmless PCBs that have been supplied in a gaseous state substantially without fail.
Examples of application of this invention's organohalogen compound pyrolysis treatment device to the treatment of dioxin-containing gas shall now be described with reference to Table 1.
1. Experimental Conditions
(a) High-frequency power supply: 50 kW, 200 V×3Φ, frequency f=10 kHz
(b) Size of pyrolysis treatment device: 465L×170W×170H
(c) Analyzing device: High-resolution gas chromatography, high-resolution mass spectrometer
2. Experimental Methods
(1) The power of the high-frequency power supply is supplied to an induction heating coil. In this process, cooling water is made to flow through the interior of the coil.
(2) Heating is performed until the central temperature of the heating unit inside the pyrolysis part becomes 1400° C.
(3) 100 mg of dioxin and 50 g of vinyl chloride are placed inside a stainless steel container and heated under air, and the vaporized dioxin-containing gas is supplied to the introduction part of the pyrolysis device.
(4) The dioxin-containing gas that has been distributed favorably by the guide member inside the introduction part is pyrolyzed by contact with the inner walls of the ceramic pipes that have been heated to 1400° C.
Though as the thermal decomposition temperature of dioxin, there is the (1) low thermal decomposition temperature of 800 to 100° C. (only the chlorine is removed but the benzene ring is not decomposed in this case) and (2) high thermal decomposition temperature of approximately 1400° C. (the chlorine is removed and the benzene ring is decomposed), the data for pyrolysis at a temperature of 1400° C. are shown for the present example (see Table 2).
(5) The pyrolysis gas that is discharged from the pyrolysis part to the discharge part is collected to the discharge part by the guide member and is discharged from the discharge port.
TABLE 2
|
|
Results of Analysis of Exhaust Gas from the Pyrolysis Treatment Device
|
Thermal decomposition temperature: 1400° C.
|
Meas-
|
ured
Toxicity
|
Item of analysis
value
equivalent (TEQ)
|
|
Dioxins
2,3,7,8-T
4
CDD
N.D
x1
0
|
1,2,3,7,8-T
5
CDD
N.D
x1
0
|
1,2,3,4,7,8-T
6
CDD
N.D
x0.1
0
|
1,2,3,6,7,8-T
6
CDD
N.D
x0.1
0
|
1,2,3,7,8,9-T
6
CDD
N.D
x0.1
0
|
1,2,3,4,6,7,8-T
7
N.D
x0.01
0
|
CDD
|
0
8
CDD
N.D
x0.0001
0
|
Total of PCDD
S
—
0
|
Dibenzofurans
2,3,7,8-T
4
CDF
N.D
x0.1
0
|
1,2,3,7,8-T
5
CDF
N.D
x0.05
0
|
2,3,4,7,8-T
5
CDF
N.D
x0.5
0
|
1,2,3,4,7,8-T
6
CDF
N.D
x0.1
0
|
1,2,3,6,7,8-T
6
CDF
N.D
x0.1
0
|
1,2,3,7,8,9-T
6
CDF
N.D
x0.1
0
|
2,3,4,6,7,8-T
6
CDF
N.D
x0.1
0
|
1,2,3,4,6,7,8-T
7
N.D
x0.01
0
|
CDF
|
1,2,3,4,7,8,9-T
7
N.D
x0.01
0
|
CDF
|
0
8
CDF
N.D
x0.0001
0
|
Total of PCDF
S
—
0
|
Total of (PCDD
S
+
—
0
|
PCDF
S
)
|
Coplanar
Non-
3,4,4′,5-H
4
CB (#81)
N.D
x0.0001
0
|
PCBs
ortho
3,3,4,4′-H
4
CB (#77)
0.1
x0.0001
0.00001
|
3,3′,4,4′,5-H
5
CB
N.D
x0.1
0
|
(#126)
|
3,3′,4,4′,5,5′-H
6
CB
N.D
x0.01
0
|
(#169)
|
Mono-
2′,3,4,4′,5-H
5
CB
N.D
x0.0001
0
|
ortho
(#123)
|
3,3′4,4′,5-H
5
CB
0.8
x0.0001
0.00008
|
(#118)
|
2,3,4,4′,5-H
5
CB
N.D
x0.0005
0
|
(#114)
|
2,3,3′4,4′-H
5
CB
0.4
x0.0001
0.00004
|
(#105)
|
2,3′4,4′,5,5′-H
6
CB
N.D
x0.00001
0
|
(#167)
|
2,3,3′4,4′,5-H
6
CB
N.D
x0.0005
0
|
(#156)
|
2,3,3′4,4′,5′-H
6
CB
N.D
x0.0005
0
|
(#157)
|
2,3,3′4,4′,5,5′-H
7
CB
N.D
x0.0001
0
|
(#189)
|
Total of C
0
-PCB
—
0.00013
|
Total of (PCDD
S
+ PCDF
S
+ Co-PCB
S
)
—
0.00013
|
|
(Note) Toxicity equivalent (TEQ): Indicates the toxicity relative to 2,3,7,8-TCDD (tetrachlorodibenzo-para-dioxin), which is strongest in toxicity among dioxins.
|
TABLE 3
|
|
Explanation of the Items of Table 2
|
Lower limit of
|
Item of analysis
quantification (ng)
|
|
Dioxins
Tetrachlorinated compounds
0.05
|
Pentachlorinated compounds
0.05
|
Hexachlorinated compounds
0.1
|
Heptachlorinated compounds
0.1
|
Octachlorinated compounds
0.2
|
Dibenzofurans
Tetrachlorinated compounds
0.05
|
Pentachlorinated compounds
0.05
|
Hexachlorinated compounds
0.1
|
Heptachlorinated compounds
0.1
|
Octachlorinated compounds
0.2
|
Coplanar PCBs
Non-ortho
0.1
|
Mono-ortho
0.1
|
|
Note 1. Measured value in Table 1: amount (ng) of dioxins in the sample.
2. Toxicity equivalent: Toxicity equivalent (ng-TEQ) relative to 2,3,7,8-T
4
CDD; calculated with the measured concentration below the lower limit of quantification being set to [0].
3. WHO (1998) was referred to for the toxicity equivalent factors.
4. N.D.: Less than the lower limit of quantification. The lower limits of quantification are as indicated above.
As can be understood from Table 2, the measured values of dioxins, dibenzofurans, and coplanar PCBs are values that adequately satisfy the environmental standards at the exit of the pyrolysis device.
Also, with the exception of three types of organochlorine compounds among the coplanar PCBs, all compounds among dioxins, dibenzofurans, and coplanar PCBs were of concentrations less than or equal to the detection limit (quantification limit).
The toxicity equivalent (TEQ) in Table 2 is the toxicity relative to 2,3,7,8-TCDD (tetrachlorodibenzo-para-dioxin), which is strongest in toxicity among dioxins. Also, the constants indicated at the left side in the toxicity equivalent (TEQ) column in Table 2 are toxicity equivalent factors and each indicates the toxicity when the toxicity of 2,3,7,8-TCDD (tetrachlorodibenzo-para-dioxin), which is the most toxic, is set to 1.
Claims
- 1. A high-frequency induction heating device comprising:an introduction part which introduces a gas to be treated, a pyrolysis part which pyrolyzes the gas to be treated, an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and an exhaust part which exhausts the gas having been decomposed in said pyrolysis part; said pyrolysis part comprising a cylindrical body both ends of which are sealed, slits which communicate the interior with the exterior of said cylindrical body provided on the outer surface of said cylindrical body, and a communication pores to be communicated with an introduction tube which introduces said gas to be treated into the interior of said cylindrical body.
- 2. The high-frequency induction heating device as claimed in claim 1, wherein said cylindrical body is provided so that the cross-section of the passage of said cylindrical body becomes smaller from the upstream towards the downstream.
- 3. A high-frequency induction heating device comprising:an introduction part which introduces a gas to be treated, a pyrolysis part which pyrolyzes the gas to be treated, an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and an exhaust part which exhausts the gas having been decomposed in said pyrolysis part; said pyrolysis part comprising a cylindrical body which introduces the gas provided so that the cross-section of the passage of said cylindrical body becomes smaller from the upstream towards the downstream.
- 4. A high-frequency induction heating device comprising:an introduction part which introduces a gas to be treated, a pyrolysis part which pyrolyzes the gas to be treated, an induction heating coil provided around the outer circumference of said pyrolysis part so as to surround and heat said pyrolysis part, and an exhaust part which exhausts the gas having been decomposed in said pyrolysis part; said pyrolysis part having a heating element having a plurality of through holes along the inside of the outer circumference of the diameter direction thereof and ceramic pipes inserted within said plurality of through holes and supported by pipe supporting plates accommodated therein.
- 5. The high-frequency induction heating device as claimed in claim 4, wherein said pyrolysis part has pressure reducing means for reducing the pressure of the body.
- 6. The high-frequency induction heating device as claimed in claim 4, wherein said pyrolysis part has compressing means for compressing the body by an inert gas.
- 7. The high-frequency induction heating device as claimed in claim 4, wherein said pipe supporting plate has a guide member for introducing a gas to be treated into said ceramic pipe.
- 8. The high-frequency induction heating device as claimed in claim 7, wherein said ceramic pipe is made of at least one member selected from the group consisting of silicon carbide and alumina.
- 9. The high-frequency induction heating device as claimed in claim 8, wherein step part to be fit to spacers are provided on both ends of said heating element.
- 10. The high-frequency induction heating device as claimed in claim 9, wherein said spacer comprises non-dielectric material and is formed from a flange having the plurality of through holes and cylindrical body.
Priority Claims (3)
Number |
Date |
Country |
Kind |
2001-222009 |
Jul 2001 |
JP |
|
2001-222010 |
Jul 2001 |
JP |
|
2002-135755 |
May 2002 |
JP |
|
US Referenced Citations (3)
Number |
Name |
Date |
Kind |
5324904 |
Cresswell et al. |
Jun 1994 |
A |
6478839 |
Kansa et al. |
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