U.S. patent application number 09/965696 was filed with the patent office on 2002-06-13 for catalyst reactor for processing hazardous gas using non-thermal plasma and dielectric heat and method threreof.
Invention is credited to Cha, Min-Suk, Choi, Yeon-Seok, Kim, Kwan-Tae, Kim, Seock-Joon, Lee, Jae-Ok, Shin, Wan-Ho, Song, Young-Hoon.
Application Number | 20020070127 09/965696 |
Document ID | / |
Family ID | 19702987 |
Filed Date | 2002-06-13 |
United States Patent
Application |
20020070127 |
Kind Code |
A1 |
Song, Young-Hoon ; et
al. |
June 13, 2002 |
Catalyst reactor for processing hazardous gas using non-thermal
plasma and dielectric heat and method threreof
Abstract
Disclosed are a reactor and a method for processing hazardous
gas, capable of improving a removing rate of the hazardous gas and
the selectivity of a reacting process using a dielectric heat
produced by a non-thermal plasma and a catalyst at a process of
decomposing the hazardous gas. The reactor comprises a body having
an inlet and an outlet; a plurality of planar electrodes arranged
parallel in the body and spaced apart from each other at a certain
interval, in which the plurality of planar electrodes are
alternately connected to an alternating current power, and a ground
such that every other planar electrode is connected to the
alternating current power and the remaining planar electrodes are
connected to the ground; and a power supply unit for applying a
voltage of an alternating current frequency to the planar
electrodes.
Inventors: |
Song, Young-Hoon; (Daejeon,
KR) ; Cha, Min-Suk; (Daejeon, KR) ; Lee,
Jae-Ok; (Daejeon, KR) ; Choi, Yeon-Seok;
(Daejeon, KR) ; Shin, Wan-Ho; (Chungcheongbuk-do,
KR) ; Kim, Kwan-Tae; (Daejeon, KR) ; Kim,
Seock-Joon; (Daejeon, KR) |
Correspondence
Address: |
Daniel F. Drexler
Cantor Colburn LLP
55 Griffin Road South
Bloomfield
CT
06002
US
|
Family ID: |
19702987 |
Appl. No.: |
09/965696 |
Filed: |
September 27, 2001 |
Current U.S.
Class: |
205/763 ;
204/277; 204/278; 204/278.5 |
Current CPC
Class: |
B01J 2219/2453 20130101;
B01J 19/249 20130101; B01J 2219/0835 20130101; B01J 2219/2467
20130101; B01J 2219/2487 20130101; B01J 2219/2488 20130101; Y02C
20/30 20130101; B01J 19/088 20130101; B01J 2219/0875 20130101; B01J
2219/2479 20130101; B01J 2219/2497 20130101; B01J 2219/0892
20130101; B01J 2219/0896 20130101 |
Class at
Publication: |
205/763 ;
204/277; 204/278; 204/278.5 |
International
Class: |
C25B 001/00; C25B
009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 12, 2000 |
KR |
2000-75601 |
Claims
What is claimed is:
1. A reactor for processing a hazardous gas using a non-thermal
plasma and a dielectric heat produced when the non-thermal plasma
is produced, the reactor comprising: a body having an inlet and an
outlet; a plurality of planar electrodes arranged parallel in the
body and spaced apart from each other at a certain interval, in
which the plurality of planar electrodes are alternately connected
to an alternating current power, and a ground such that every other
planar electrode is connected to the alternating current power and
the remaining planar electrodes are connected to the ground; and a
power supply unit for applying a voltage of an alternating current
frequency to the planar electrodes.
2. The reactor as claimed in claim 1, wherein each of the planar
electrodes comprises a first dielectric plate and a second
dielectric plate, a first side of each of the first and second
dielectric plates being coated with a metallic thin film and a
second side of each of the first and second dielectric plates being
coated with a catalyst, and the first and second dielectric plates
being adhered such that the metallic thin film of the first
dielectric plate faces to the metallic thin film of the second
dielectric plate.
3. The reactor as claimed in claim 2, wherein each of the
dielectric plates has a thickness of 0.1 to 2 mm.
4. The reactor as claimed in claim 2, wherein the dielectric plate
comprises any one selected from the group consisting of ceramic,
glass, and quartz.
5. The reactor as claimed in claim 2, wherein the catalyst is a
metallic catalyst-containing at least one metal element selected
from the group consisting of Pt, Pd, V, and Rh.
6. The reactor as claimed in claim 2, wherein the catalyst is a
zeolite catalyst containing at least one zeolite selected from the
group consisting of MS 5A and MS 3A.
7. The reactor as claimed in claim 2, wherein the catalyst is a
photo catalyst containing TiO.sub.2.
8. The reactor as claimed in claim 1, wherein the power supplied to
each of the planar electrodes by the power supply unit is an
alternating current voltage of 1 kV to 30 kV at a frequency of 50
Hz to 100 kHz.
9. The reactor as claimed in claim 1, wherein each of the planar
electrodes comprises two dielectric plates, a metallic thin film
interposed therebetween, and a catalyst layer coated on an outer
surface of each of the dielectric plates which is opposed to an
inner surface facing the metallic thin film.
10. The reactor as claimed in claim 9, wherein each of the
dielectric plates has a thickness of 0.1 to 2 mm.
11. The reactor as claimed in claim 9, wherein the dielectric plate
comprises any one selected from the group consisting of ceramic,
glass, and quartz.
12. The reactor as claimed in claim 9, wherein the catalyst is a
metallic catalyst-containing at least one metal element selected
from the group consisting of Pt, Pd, V, and Rh.
13. The reactor as claimed in claim 9, wherein the catalyst is a
zeolite catalyst containing at least one zeolite selected from the
group consisting of MS 5A and MS 3A.
14. The reactor as claimed in claim 9, wherein the catalyst is a
photo catalyst containing TiO.sub.2.
15. A method for processing a hazardous gas, the method comprising:
installing a plurality of planar electrodes parallel in a reactor,
each of planar electrode comprising two dielectric plates, each of
the dielectric plates including a catalyst layer coated on an outer
surface thereof, and the plurality of planar electrodes being
alternately connected to an alternating current power and a ground;
applying an alternating current voltage of an alternating current
frequency to the planar electrodes to produce a non-thermal plasma
and a dielectric heat; supplying the hazardous gas into the
reactor; and carrying out a plasma reaction and a catalysis
reaction on the hazardous gas to cause a decomposition of the
hazardous gas.
16. The method as claimed in claim 15, further comprising
periodically supplying a pure air and oxygen into the reactor for
removing a by-product of liquid and solid forms produced in the
reactor.
17. The method as claimed in claim 15, wherein the hazardous gas is
at least any volatile organic compound selected from the group
consisting of perfluoro-compounds, chlorofluorocarbons,
trichloroethylene, dioxin, and nitrogen oxides.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a reactor and a method for
processing a hazardous gas using a non-thermal plasma technology
and a dielectric heat, and more particularly to a reactor and
method for processing hazardous gas, capable of improving a
removing rate of the hazardous gas and the selectivity of a
reacting process using a dielectric heat produced by a non-thermal
plasma and catalyst at a process of decomposing the hazardous
gas.
[0003] 2. Description of the Related Art
[0004] Generally, since volatile organic compounds (VOC) discharged
from industries are substances causing photochemical smog to be
happened in the atmosphere, as well as being harmful to human,
several countries control and regulate the emission of contaminants
into the atmosphere. Meanwhile, according to the United Nations
Framework Convention on Climate Change, the regulation concerning
the emission of perfluorocarbon (PFC) and chlorofluorocabon (CFC),
which are substances causing the global climate to warm, has set
stricter in stages. For example, the total amount of emission of
these substances will be regulated from 2002 year. Accordingly,
various technologies for decomposing compounds such as PEC and CFC
have been investigated, including: incineration, catalysis,
absorption or biological filtration. Unfortunately, many of these
technologies are not able to efficiently satisfy the regulation
concerning the emission of the hazardous gas. The technology using
incineration and catalysis needs indispensably a high heat source,
but such high heat source cannot be continuously maintained in
industry such as a process of manufacturing a semiconductor device,
in which the hazardous gas is intermittently discharged. In order
to maintain the high heat source, high expensive cost is
required.
[0005] Meanwhile, there is another technology for decomposing or
oxidizing hazardous gas using non-thermal plasma, without using a
high heat source. One example is disclosed in U.S. Pat. No.
5,236,672 issued to Nunez et al. According to the Nunez et al.
patent, a non-thermal plasma consisting of electrons and ions is
produced by applying an AC power of high voltage to a plasma
reactor, in which dielectric or ferroelectric pellets or beads
having a diameter of a few millimeters are filled. The hazardous
gas is decomposed with the chemical reaction due to the portion of
energy produced in the reactor. However, such technology for
decomposing the hazardous gas needs a high power cost. In addition,
by-product of aerosol state, which is produced at the decomposing
process, is attached to a surface of the electrode as well as
packed materials, thereby interrupting the operation of the reactor
or causing the reactor to be clogged. Therefore, there is a problem
that such technology cannot be realized in practice.
[0006] In addition, similar to the Nunez et al. patent, reactive
bed plasma air purification is disclosed in U.S. Pat. No. 4,954,320
issued to Birmingham et al, in which the reactor is filled with
noble metal catalyst beads, alumina beads or absorbents, thereby
absorbing with the non-thermal plasma or producing catalysis
reaction. Also, U.S. Pat. No. 5,843,288 issued to Yamamoto
discloses technology of coating transition group of metal catalyst,
such as Pt, Pd, Co, Ni or the like, on a surface of a ferroelectric
bead to reduce by-products of gas state produced in the reactor and
the alternating current power unit disclosed in the above
patents.
[0007] As described above, the reactor for processing hazardous gas
using non-thermal plasma includes a tubular body, in which
dielectric pellets or beads are filled. In case of using the
catalysis process together with the plasma, the dielectric pellets
or beads are coated with a catalyst. However, if the above
technologies are employed in a process of discharging the hazardous
gas in practice, the pressure loss is happened due to the packed
dielectric material in the reactor. Also, particulate materials
contained in the discharged gas would lead the reactor to be
clogged. In addition, if such a reactor is employed in an engine
for a transport, which generates a vibration inevitably, interfaces
of pellets or beads may be clacked. Furthermore, since a number of
tubular reactors must be provided in a bundle in order to process a
large volume of discharged gas, there is a problem that the size of
the entire system is huge.
[0008] In particular, if the volume or capacity of the reactor is
increased, the utility thereof is problematic, and the dielectric
heat produced by the alternating current is not concentrated into a
reacting space. Therefore, since the performance of the catalyst
activated by the heat does not come up to expectations, the energy
efficiency of the entire processes is significantly reduced.
[0009] The process utilizing both the non-thermal plasma and the
catalysis needs new technology having a reactor structure of a
small volume, the reactor can utilize the dielectric heat from the
operation of AC more effectively, without disturbing the flow of
gas.
SUMMARY OF THE INVENTION
[0010] Therefore, in order to solve the problems involved in the
prior art, it is an object of the present invention to provide a
reactor for processing hazardous gas using non-thermal plasma and
dielectric heat, by which the pressure loss and the clogging can be
prevented.
[0011] It is other object of the present invention to provide a
reactor for processing hazardous gas, by which a lot of gas in a
small space can be decomposed.
[0012] It is anther object of the present invention to provide a
reactor for processing hazardous gas, by which the heat produced
from the plasma is concentrated onto a narrow space, so that a
catalyst coated on an electrode surface is effectively activated by
the heat, thereby reducing its operating power.
[0013] It is still another object of the present invention to
provide a reactor for processing hazardous gas capable of
preventing by-product of a liquid or solid state from being
produced.
[0014] It is further still object of the present invention to
provide a method for processing hazardous gas using the above
reactor.
[0015] The present invention relates to a reactor and a method for
processing a hazardous gas using a non-thermal plasma and a
catalyst at same time, the hazardous gas comprising volatile
organic compounds, perfluoro-compounds, chlorofluorocarbons,
trichloroethylene, dioxin, and nitrogen oxide, wherein the catalyst
and the electric heat which is not used in the prior art
non-thermal plasma reactor are effectively employed, thereby
decreasing the power needed for the operator, and suppressing the
production of the by-product of particles or liquid.
[0016] In order to achieve the above objects, according to one
aspect of the present invention, there is provided a reactor for
processing hazardous gas using non-thermal plasma and dielectric
heat produced when the non-thermal plasma is produced, the reactor
comprising: a body having an inlet and an outlet; a plurality of
planar electrodes arranged parallel in the body and spaced apart
from each other at a certain interval, in which the plurality of
planar electrodes are alternately connected to an alternating
current power, and a ground such that every other planar electrode
is connected to the alternating current power and the remaining
planar electrodes are connected to the ground; and a power supply
unit for applying a voltage of an alternating current frequency to
the planar electrodes.
[0017] Each planar electrode includes two dielectric plates, one
side of the dielectric plate is coated with a metallic thin film
and the other side is coated with a catalyst. The two dielectric
plates are adhered in such a manner that the metallic thin film of
one dielectric plate faces to the metallic thin film of the other
dielectric plate.
[0018] Preferably, the dielectric plate has a thickness of 0.1 to 2
mm, and is made of one among ceramic, glass, and quartz.
[0019] The catalyst is any one selected from a metallic catalyst
group containing Pt, Pd, V, and Rh, a zeolite catalyst group
containing MS 5A and MS 3A, and a photo catalyst group containing
TiO.sub.2.
[0020] The power supplied to the planar electrode by the power
supply unit is an alternating current voltage of 1 kV to 30 kV at a
frequency of 50 Hz to 100 kHz.
[0021] According to another aspect of the present invention, there
is provided a method for processing hazardous gas using the
reactor, the method comprising: installing a plurality of planar
electrodes parallel in a reactor, each of planar electrode
comprising two dielectric plates, each of the dielectric plates
including a catalyst layer coated on an outer surface thereof, and
the plurality of planar electrodes being alternately connected to
an alternating current power and a ground; applying an alternating
current voltage of an alternating current frequency to the planar
electrodes to produce a non-thermal plasma and a dielectric heat;
supplying the hazardous gas into the reactor; and carrying out a
plasma reaction and a catalysis reaction on the hazardous gas to
cause a decomposition of the hazardous gas.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The above objects, other features and advantages of the
present invention will become more apparent by the preferred
embodiment described with reference to the accompanying drawings,
in which:
[0023] FIG. 1 is a perspective view illustrating the construction
of a reactor for processing hazardous gas using non-thermal plasma
according to a preferred embodiment of the present invention;
[0024] FIG. 2 is a perspective view illustrating the arranging
state of a planar electrode of a reactor shown in FIG. 1;
[0025] FIG. 3 is a view illustrating the construction of a planar
electrode in FIG. 2.; and
[0026] FIG. 4 is a graph showing the efficiency of non-thermal
plasma and a catalyst used for a reactor according to one
embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] Now, a reactor for processing hazardous gas using
non-thermal plasma and dielectric heat according to the present
invention and an apparatus for processing the hazardous gas using
the reactor will be described in detail with reference to
accompanying drawings.
[0028] Referring FIGS. 1 and 2, the reactor for processing
hazardous gas using non-thermal plasma and dielectric heat
according to the present invention comprises a cubic body 10 with a
desired space therein. The body is provided on its front with a
flow distributor 14 having an inlet 12 for injecting the hazardous
gas into the body. The body also includes an outlet (not
shown).
[0029] In particular, the body 10 includes two or more planar
electrodes 16. Preferably, each electrode 16 has a cubic shape. The
planar electrode 16 includes two dielectric plates 18 made of a
material such as ceramic, glass, or quartz, these materials having
both electrically insulating property and dielectric property. Each
dielectric plate 18 may have a thickness of 0.1 to 2 mm. In
addition, a dimension of each dielectric plate 18 may be determined
depending upon the whole capacity of the reactor, so its length and
width may be selected from a few mm to several hundreds mm.
[0030] Preferably, each dielectric plate 18 has one side applied
with a metallic coating or metallic thin film 20 to conduct
electricity, and the other side applied with catalyst or an
adsorbent 22.
[0031] Each planar electrode 16 is made by closely contacting two
dielectric plates 18. Specifically, one side of one dielectric
plate 18, on which the metallic thin film 20 is applied, is adhered
to one side of the other dielectric plate 18, on which the metallic
thin film 20 is applied, so that one planar electrode 16 is
formed.
[0032] Alternatively, the planar electrode may be formed by
interposing a metallic thin film between two dielectric plates. At
that time, it is unnecessary to apply the metallic thin film on the
adhered surface of each dielectric plate.
[0033] The planar electrodes 16 formed by the above process are
arranged in parallel in the body of the reactor, as shown in FIG.
2. In the accompanying figure, while only seven planar electrodes
are shown, the number of the planar electrodes may be optionally
set depending upon the performance or volume of the reactor. One is
connected to an AC supply 24, while the other is connected a ground
26. Preferably, a distance between two adjacent planar electrodes
is about 1 to 6 mm. In addition, the planar electrode 16 may be
arranged in parallel in several tens or hundreds pairs depending
upon the performance of the reactor or a flow rate of the gas to be
processed. Preferably, the body forming an outside part of the
reactor may be made of ceramic, so that the body can stand the high
temperature, as well as having an electrically insulating
property.
[0034] A power supply unit 28 connected to each planar electrode 16
of the reactor supplies an alternating current of 5 to 20 kV at a
specific frequency of several tens Hz or several hundred thousands
Hz. Preferably, an inductance and a charging circuit (not shown)
may be provided between the power supply unit and the reactor, in
order to achieve the impedance matching between the power supply
unit and the reactor.
[0035] In addition, the catalyst coated on the dielectric plate may
be one or more selected from metal catalysts containing Ni, Cu, Co
or the like, as well as noble catalysts containing Pt, Rd, Pd or
the like, which are known to cause the catalyst to be activated due
to the heat. In order to increase a contact surface area between
the metallic catalyst and a reacting gas, after a smooth ceramic
planar plate of the dielectric plate 18 is applied with
.gamma.-alumina, silica, or zeolite, the metallic catalyst may be
coated thereon.
[0036] In addition, the adsorbent may be .gamma.-alumina or
zeolite. Preferably, the zeolite is molecular sieve 3A or 5A. The
superior performance may be achieved by using a catalyst
substituted with alkali earth metal on such molecular sieve.
[0037] With the construction as described above, if the power
supply unit 28 supplies a power to the reactor, an electric
discharge is happened between the planar electrodes 16, thereby
producing electrons and ions. The produced electrons decompose
directly a gas molecule to be processed, or are oxidized or
deoxidized by O, OH, HO.sub.2, N radical or ion produced due to the
collision between electrons and air or added gas molecules which
are supplied together with hazardous gas to be processed. The above
reacting process is the principle of the typical non-thermal
plasma.
[0038] The reactor according to the present invention raises the
temperature therein using the dielectric heat to easily achieve the
desired reaction, and may achieve a combined effect of the
non-thermal plasma reaction and the catalysis reaction by
activating the catalyst using the heat generated by the dielectric
heat in the reactor. In particular, the combined effect of the
non-thermal plasma reaction and the catalysis reaction has an
advantage as follows, in relative to the prior non-thermal plasma
reaction or catalysis reaction.
[0039] While the prior process has to heat the catalyst above a
specific temperature in case of oxidizing the hazardous gas using
the catalyst, the present invention using both non-thermal plasma
reaction and catalysis reaction lowers the temperature, at which
the catalyst is activated, so that the process can be performed at
a lower temperature. The reason is that the hazardous gas or an
oxidizing agent (for example, oxygen, moisture or additive) is
changed into a state, of which is easily reacted in the space of
the non-thermal plasma.
[0040] In addition, while there is not much possibility of a
specific reaction which is selectively happened in the prior
non-thermal plasma reaction, the selectivity of reaction may be
increased by using the catalyst together with the non-thermal
plasma. Specifically, in case of removing toluene using the
non-thermal plasma reaction only, half or more of toluene is
polymerized and is transformed into an aerosol form. Such material
is attached to the surface of the electrode, thereby interrupting
the drive of the reactor or causing the clogging phenomenon of the
reactor. In case of using the catalyst activated by the dielectric
heat, the reaction product is easily oxidized, finally converted
into carbon dioxide and water.
[0041] The operation and working effects of the present invention
will now be described.
EXAMPLE 1
[0042] A dimension of the planar electrode 16 is 76 mm.times.76
mm.times.1 mm, a dimension of the inner metallic thin film 20 is 60
mm.times.60 mm.times.0.1 mm, the number of the planar electrodes 16
is 15 and a distance between two adjacent planar electrodes 16 is 2
mm. Between two adjacent planar electrodes 16, a reacting space is
formed. The reactor is applied with an alternating current of
voltage 11 kV and frequency 60 Hz, to produce the non-thermal
plasma. At that time, although the power supply was continued
during 5 to 6 hours, and the above process was repeated by 10
times, there was no found serious damage due to the insulating
destruction in the reactor. Meanwhile, the dielectric plate 18 of
the planar electrode 16 may be one selected from a .alpha.-alumina
plate, a .alpha.-alumina plate with .gamma.-alumina and platinum
coated, a .alpha.-alumina plate with zeolite coated, a quartz plate
or the like.
EXAMPLE 2
[0043] When an air was injected into the reactor constructed as
described in Example 1, and the reactor was applied with the
frequency increased from 60 Hz to 10 kHz, the power was increased
in relative to the applied frequency, such that the temperature in
the reactor and the temperature of the air discharged from a rear
end of the reactor were increased. Meanwhile, while the actual
surface area of the electrode on which the non-thermal plasma is
produced in the reactor is 6 cm.times.6 cm.times.14.times.2=1008
cm.sup.2, the surface area contacted with the exterior is 6
cm.times.6 cm.times.6=216 cm.sup.2. In other words, since the
surface area contacted with the exterior, by which a heat loss may
be produced, is significantly reduced in relative to the surface
area of the electrode, by which the dielectric heat is produced,
the produced heat may be effectively used in the reacting process.
By contrast, according to a conventional reactor of a tube shape,
because the contacted surface area is similar to the surface area
of the electrode, a lot of heat loss is happened, and so the heat
needed to the reaction is not effectively used.
EXAMPLE 3
[0044] When an air was injected into the reactor constructed as
described in Example 1, the pressure loss at each front end and a
rear end of the reactor was significantly reduced in relative to
that of the conventional reactor of a tube shape, in which the
reactor is filled with beads or pellets and the air flows in the
reactor. Accordingly, the reactor according to the present
invention may be used in a process of high flow rate, and if
particles are generated at the reacting process, there is no
clogging phenomenon in the reactor.
[0045] Specifically, in case that the air containing toluene of
several tens ppm to several hundreds ppm is supplied into the
reactor and is processed for a long time, a portion of toluene is
not oxidized, but is transformed into carbon compounds of
particles, thereby adhering to the electrode. The adhered
by-product causes the electric property of the electrode to be
changed and provides a problem of power supply. However, according
to the present invention, if the platinum catalyst inducing the
oxidation reaction is coated on the electrode plate, the production
of the by-product of particles or liquid is significantly reduced,
and after a certain period, the adhered carbon compounds can be
removed by injecting the air only.
COMPARATIVE EXAMPLE 1
[0046] In order to examine the influence of the catalyst and the
heat on the decomposing performance of the hazardous gas, toluene
of 300 ppm as the hazardous gas is supplied to the reactor together
with the air, and immediately, the alternating current of 11 kV is
applied to the reactor at a frequency of 60 Hz. At that time, the
concentration of the toluene discharged from the rear end of the
reactor is measured. For the clarity of comparison, the planar
electrodes are used as following; 1) the planar electrode of a
.alpha.-alumina plate, 2) the planar electrode of a .alpha.-alumina
plate with .gamma.-alumina coated, and 3) the planar electrode of a
.alpha.-alumina plate with .gamma.-alumina and platinum coated. In
addition, in order to examine the effect of the increased
temperature at the oxidization of volatile organic compound such as
toluene, an operating temperature (a temperature of the air
supplied to the reactor and the environment) of each electrode is
set to a room temperature, 60.degree. C. and 100.degree. C.
[0047] The results obtained from the above experiment are shown as
a graph in FIG. 4. According to the graph, even though the power
supply unit consumes same power, the decomposing rate (the
decomposed concentration relative to an initial concentration) of
the toluene is increased in order of the planar electrodes of
.alpha.-alumina, .gamma.-alumina, and a platinum catalyst.
Meanwhile, in case that the operating temperature is increased in
each case, the decomposing rate of the toluene is increased,
thereby affirmatively affecting the increased temperature on the
reacting process.
COMPARATIVE EXAMPLE 2
[0048] In the experiment that the reactor according to the present
invention decomposes NF.sub.3 and CF.sub.4 as the hazardous gas,
these components belonging to PFC, the decomposing rate is also
increased in proportion to the increased temperature in the
reactor, as the above case of toluene. In particular, because
NF.sub.3 is merely decomposed by the heat if the temperature in the
reactor is above 400.degree. C., the increase of the decomposing
rate by the reactor is observed, without using the catalysis.
[0049] Meanwhile, because CF.sub.4 can be decomposed at a
temperature of above 1200.degree. C. to 1800.degree. C., there
needs an electrode with platinum catalyst coated. In case of using
the platinum catalyst, when the non-thermal plasma is produced
while the temperature in the reactor is maintained in a level of
300.degree. C. to 400.degree. C., CF.sub.4 begins to be
decomposed.
[0050] In addition, in case of decomposing the organic compound
such as trichloroethylene (TCE) containing Cl, the increased
temperature causes the oxidizing reaction of the hazardous compound
to be accelerated. Therefore, the technology of increasing the
reacting temperature according to the present invention may be
employed to decompose the inorganic compound such as dioxin, PFC,
CFC and nitric oxide, as well as VOC such as toluene.
[0051] As described above, according to the reactor and method for
processing the hazardous gas using the non-thermal plasma and the
dielectric heat according to the present invention, the dielectric
heat produced when the non-thermal plasma is produced by the AC
power supply and the dielectric electrode may be used together with
the catalyst in the reacting process, thereby improving the
reacting efficiency.
[0052] In addition, the pressure loss is reduced in the reactor,
and the maintenance of the reactor is easy, and the volume of the
reactor is small.
[0053] Although a preferred embodiment has been described, many
modifications and variations may be made thereto in the light of
the above teachings. It is therefore may be practiced otherwise
than as specifically described.
* * * * *