JP2011147874A - Complex type exhaust gas treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a complex type exhaust gas treatment apparatus capable of effectively decomposing an exhaust gas that is a treatment object and economically manufacturing an entire apparatus. <P>SOLUTION: A high voltage pulse-type gas treatment section 10 that polarizes at least the exhaust gas 3 is installed on a front stage between a gas inflow section 1 and a gas discharge section 2 of the exhaust gas 3 that is the treatment object, and a catalyst-type gas treatment section 20 that adsorbs and oxidatively decomposes the exhaust gas 3 is installed on a rear stage so that the former and the latter configure the complex-type exhaust gas treatment apparatus to treat the exhaust gas 3 in a separate step. The high voltage pulse-type gas treatment section 10 has a line electrode 11 and an external electrode 12; the line electrode 11 is connected to a high voltage pulse power supply 13 and the external electrode 12 is grounded; a high voltage pulse discharge is generated between the two electrodes, thereby enabling the exhaust gas to be polarized. The catalyst-type gas treatment section 20 has a direct current power supply 24 that installs a plurality of photocatalyst sections 22 in the section of an exhaust gas channel and is connected to the photocatalyst sections 22 to apply direct current and an ultraviolet lamp 25 that activates the photocatalyst. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a combined exhaust gas processing apparatus, and more particularly to a combined exhaust gas processing apparatus that separately processes exhaust gas using a high voltage pulse discharge and a photocatalyst.

  A large amount of exhaust gas discharged from factories and various incineration facilities should be released to the outside after appropriate normalization before discharge, especially from the viewpoint of environmental measures in the vicinity and the global environment. Has been required. For example, when the exhaust gas has a bad odor, it is necessary to deodorize the exhaust gas by some means and then discharge it.

  As a deodorizing apparatus for treating the exhaust gas to be treated, a system utilizing a high voltage pulse discharge or a system utilizing a photocatalyst is known. Both types of deodorizing apparatuses can be applied to a wide range of exhaust gas, and can be expected to have an effective gas decomposition effect.

  However, in the former system, if a large volume of exhaust gas is to be processed, the pulse generating power source becomes large and expensive. In the latter system, since the oxidation reaction field is only on the surface of the photocatalyst, it is necessary to take measures to take a long time to bring the gas into contact with the surface of the photocatalyst, and to decompose the large volume of the target gas. Attempting to do so makes the entire device very large.

  As an apparatus for treating exhaust gas by using both of the above-described methods, for example, a harmful component treatment apparatus described in Patent Document 1 has been proposed. This apparatus uses coaxially arranged line electrodes and cylindrical electrodes for generating discharge plasma. Then, a pulse power source is connected so that the line electrode is a positive electrode and the cylindrical electrode is a negative electrode, and the pulse power source is connected between both electrodes so as to apply a pulse voltage, and is installed on the inner surface of the negative electrode of the cylindrical electrode. A photocatalyst is provided.

  And the apparatus of the said patent document 1 decomposes | disassembles the harmful substance in the exhaust gas introduce | transduced between electrodes using the plasma discharge which generate | occur | produces when a pulse voltage is applied from a pulse power supply. At the same time, by irradiating the photocatalyst with ultraviolet light emitted by plasma discharge, the photocatalytic action is activated to decompose harmful substances and exhaust the harmless exhaust gas.

JP 2000-354737 A

  The apparatus disclosed in Patent Document 1 can simultaneously process the target gas by plasma decomposition of the pulse discharge part and oxidation action of the catalyst part. However, since the pulse discharge portion has an electrode structure with a coaxial arrangement, a certain amount of length is required for processing the target gas, so that the gas flow tends to be a laminar flow.

  For this reason, when the target gas is flowed into the cylindrical electrode, the flow velocity at the center is fast and the flow velocity on the outer diameter side is slow.Therefore, the amount of gas in contact with the photocatalyst disposed on the inner surface of the cylindrical electrode is very small, and the gap between the electrodes The diameter of the cylindrical electrode cannot be increased due to the relationship of the applied voltage. For this reason, the flow velocity of the entire gas in the cylindrical electrode is increased, the surface area of the cylindrical electrode cannot be increased, and the number of photocatalysts to be disposed is also reduced, so that the target gas cannot be sufficiently processed.

  Moreover, since the apparatus of patent document 1 functions a photocatalyst with the ultraviolet light which generate | occur | produces at the time of the pulse discharge of a pulse discharge part, an ultraviolet light generate | occur | produces at the time of intermittent discharge. For this reason, not only the ultraviolet light can be effectively applied to the photocatalyst, but also the streamer component by pulse discharge alone cannot provide sufficient ultraviolet intensity to effectively function the photocatalyst, and the target gas is sufficiently processed. There is a problem that disappears.

  An object of the present invention is to provide a combined exhaust gas processing apparatus that can effectively decompose exhaust gas to be processed and can economically manufacture the entire apparatus.

  The combined exhaust gas treatment apparatus of the present invention treats exhaust gas using plasma and a catalyst by pulse discharge, and is installed in a preceding stage on the gas inflow side so that at least the exhaust gas has polarity. A voltage pulse type gas processing unit and a catalyst type gas processing unit that is installed in a subsequent stage of the high voltage pulse type gas processing unit and adsorbs the exhaust gas to oxidatively decompose are provided separately. It is said.

  The combined exhaust gas treatment apparatus of the present invention treats exhaust gas using plasma and a catalyst by pulse discharge, and is installed in the preceding stage on the gas inflow side to at least polarize the exhaust gas. A high-voltage pulse type gas processing unit and a catalyst-type gas processing unit that is installed at a subsequent stage of the high-voltage pulse type gas processing unit and adsorbs the exhaust gas to oxidatively decompose the high-voltage pulse type gas processing unit, The gas processing unit has two electrodes and a high voltage pulse power source that applies one intermittent high voltage pulse by grounding one of the electrodes and connecting the other electrode, and the catalytic gas processing unit includes: A catalyst unit disposed in the exhaust gas flow path; a DC power source that is connected to the catalyst unit and applies a DC voltage having a polarity opposite to the applied voltage of the high-voltage pulse power source; and an ultraviolet ray that activates the catalyst unit With a light Is characterized in that form was.

  Preferably, the catalyst part is constituted by a charging plate type in which a catalyst is applied to a metal mesh plate.

  Preferably, the two electrodes of the high voltage pulse gas processing unit are constituted by a line electrode and a cylindrical external electrode on the ground side arranged coaxially with the line electrode.

  More preferably, the two electrodes of the high-voltage pulse type gas processing unit are constituted by a line electrode and a ground-side arc-shaped external electrode which is disposed so as to surround the line electrode and face each other.

  More preferably, the two electrodes of the high-voltage pulse gas processing unit are constituted by a line electrode and a flat plate-like external electrode on the ground side that surrounds and opposes the line electrode.

  The composite exhaust gas treatment device of the present invention is configured to combine the high voltage pulse gas treatment unit and the catalyst exhaust gas treatment unit having independent structures in an appropriate combination and perform exhaust gas treatment in a separate process. Since the exhaust gas to be treated can be effectively decomposed, the exhaust gas treatment efficiency can be improved, and the entire apparatus does not need to be enlarged, so that it can be manufactured economically.

  The composite exhaust gas treatment device of the present invention combines a high voltage pulse gas treatment unit and a catalyst exhaust gas treatment unit having independent structures in an appropriate combination, and includes two high voltage pulse gas treatment units. An electrode and a high voltage pulse power source for grounding one of the electrodes and connecting the other electrode to apply intermittent high voltage pulses, and the catalytic gas processing unit is disposed in the exhaust gas flow path And a catalyst unit that is connected to the catalyst unit, a DC power source that applies a DC voltage having a polarity opposite to the applied voltage of the high-voltage pulse power source, and an ultraviolet lamp that activates the catalyst unit. The exhaust gas can be further effectively decomposed by utilizing the respective advantages.

(A) is a schematic longitudinal cross-sectional view which shows the composite type exhaust gas processing apparatus which is one Example of this invention, (b) is sectional drawing of the AA line of (a). (A) is a schematic longitudinal cross-sectional view which shows the composite type exhaust gas processing apparatus which is another Example of this invention, (b) is sectional drawing of the BB line of (a). (A) is a schematic longitudinal cross-sectional view which shows the composite type exhaust gas processing apparatus which is another Example of this invention, (b) is sectional drawing of CC line of (a). It is a schematic longitudinal cross-sectional view which shows the composite type exhaust gas processing apparatus which is another Example of this invention. It is a graph which shows the relationship between the number of repetition pulses and ammonia concentration.

  The combined exhaust gas treatment apparatus of the present invention has a high voltage pulse type gas treatment unit installed in the former stage on the gas inflow side of the exhaust gas to be treated and a catalyst type gas treatment unit installed in the latter stage independently of each other. It is prepared. The exhaust gas is at least polar in the high voltage pulse gas processing unit, and the catalytic gas processing unit adsorbs the exhaust gas to perform oxidative decomposition. Embodiments of the present invention will be described in order with reference to FIGS.

  In the combined exhaust gas treatment apparatus of the present invention shown in FIG. 1, a high-voltage pulse gas treatment unit is disposed between the gas inflow part 1 side which is an inlet of exhaust gas to be treated and the gas exhaust part 2 side of the outlet. 10 and the catalyst type gas processing unit 20 are sequentially installed in the subsequent stage. Thereby, the exhaust gas 3 entering from the gas introduction unit 1 side is processed in a process of passing through the processing units 10 and 20 via the high-voltage pulse type gas processing unit 10 and the catalyst type gas processing unit 20, The gas is discharged from the gas discharge unit 2.

  The high voltage pulse gas processing unit 10 has two electrodes, a central line electrode 11 and a cylindrical external electrode 12 arranged coaxially therewith, and one line electrode 11 is connected to a high voltage pulse power source 13. The other external electrode 12 is grounded.

  The high voltage pulse power source 13 is controlled by a control circuit 14 that generates high voltage intermittent pulses, and in the example of FIG. 1, a negative high voltage pulse is applied to the line electrode 11. Thus, by applying a high voltage pulse from the high voltage pulse power supply 13, a high voltage pulse discharge is generated between the electrodes 11 and 12.

  In the catalytic gas processing unit 20, a plurality of photocatalytic units 22 are arranged in the exhaust gas flow path in the container 21. Each photocatalyst unit 22 is insulated and supported by an insulator 23. In the example of FIG. 1, each photocatalyst unit 22 is connected to a DC power source 24 and applies a positive DC voltage.

The photocatalyst portion 22 uses a charged plate type in which a metal mesh plate such as a wire mesh is provided with a photocatalyst such as titanium oxide (TiO ₂ ). In addition, in order to activate the photocatalyst, the ultraviolet lamp 25 is disposed in the container 21 so as to face the photocatalyst portion 22.

  The photocatalyst unit 22 may be made of a metal base catalyst other than a photocatalyst such as titanium oxide. The exhaust gas activated by pulse discharge and the metal base catalyst are brought into contact with each other to perform an oxidative decomposition reaction. It can also be promoted.

  In the high voltage pulse gas processing unit 10 described above, the exhaust gas 3 to be processed passes through the external electrode 12 during the high voltage pulse discharge between both the electrodes 11 and 12. For this reason, the exhaust gas 3 is subjected to a gas decomposition action by pulse discharge, and the exhaust gas 3 passing through the residual charge at the time of pulse discharge is activated in the charged state of the negative electrode.

  The exhaust gas 3 charged to the negative electrode by the high voltage pulse discharge is easily adsorbed to the photocatalyst, and the photocatalytic unit 22 of the subsequent catalytic gas processing unit 20 is applied with positive polarity by the DC power source 24. Therefore, it is more efficiently adsorbed and comes into contact with the photocatalyst. Therefore, the exhaust gas 3 is oxidized and decomposed by the photocatalyst of the photocatalyst unit 22 and is exhausted from the gas discharge unit 2.

  In the combined exhaust gas processing apparatus of the present invention having the above-described configuration, the high voltage pulse discharge method and the photocatalyst method that perform exhaust gas processing in separate steps can be combined to make up each disadvantage with each advantage. Become. In addition, the exhaust gas processing efficiency can be improved as compared with a single device, and since it is combined, the overall size of the device can be reduced and it can be manufactured economically.

  Next, the deodorization decomposition | disassembly experimented with the exhaust gas containing ammonia is demonstrated using FIG. When the initial concentration of ammonia used as the exhaust gas is 15 ppm, the treatment with the photocatalyst alone is about 13 ppm. In a single process using the high-voltage pulse gas processing unit 10 to which no photocatalyst and ultraviolet light are applied and a repetitive pulse number (200 pps) is applied, 15 ppm is reduced to 7 ppm as shown by the characteristic line connecting the marks ■. The concentration of is reduced.

  On the other hand, as in the configuration of the composite exhaust gas processing apparatus described above, the high voltage pulse type gas processing unit 10 having a repetitive pulse number (200 pps) and the catalytic type gas processing unit 20 for irradiating the photocatalyst with ultraviolet light are combined in series. In this case, even when different types of ultraviolet lamps were used, the ammonia concentration was reduced from 15 ppm to about 2 ppm, as indicated by the characteristic lines connecting the □ and ▲ marks.

  The examples shown in FIGS. 2A and 2B show the structure of a combined exhaust gas processing apparatus of the present invention that processes a large amount of exhaust gas. The high voltage pulse gas processing unit 10 is shown in FIGS. 2A and 2B in which a line electrode 11 connected to the negative high voltage pulse power source 13 and an external electrode 12 to be grounded are arranged coaxially. In this manner, a plurality of juxtapositions are arranged, and the exhaust gas is passed through each external electrode 12 for processing.

  Further, the catalyst-type gas processing unit 20 at the rear stage has a plurality of sheets connected to the positive DC power source 24 in the same manner as described above in the portion of the exhaust gas flow path in the container 21 formed so as to allow a large amount of exhaust gas to flow. The photocatalyst portion 22 is disposed through an insulator 23 that insulates and supports, and an ultraviolet lamp 25 that improves the function of the photocatalyst is also disposed.

  This combined exhaust gas processing apparatus can achieve the same effect as the above-described embodiment, and can process exhaust gas flowing in parallel to each external electrode even when the exhaust gas is exhausted in a large amount. Therefore, it is suitable as a large capacity processing apparatus.

  The composite type exhaust gas processing apparatus of the present invention shown in FIGS. 3A and 3B has a structure suitable for processing a large amount of exhaust gas as in the example of FIG. In this example, as electrodes to be combined with the line electrode 11 of the high-voltage pulse gas processing unit 10, arc-shaped external electrodes 12 are arranged to face each other at a predetermined interval, and the space between both arc-shaped external electrodes is defined as a gas passage. The other points are the same as those shown in FIG. The combined exhaust gas treatment device having this structure can also achieve the same effects as in FIG.

  Similarly, the combined exhaust gas processing apparatus of the present invention shown in FIG. 4 has a structure suitable for processing a large amount of exhaust gas. The two electrodes in this example use a line electrode 11 and a flat plate-like external electrode 12 disposed opposite thereto, and the other points are the same as those shown in FIG. The composite exhaust gas treatment apparatus having the structure in which the electrodes are arranged in this way can also achieve the same effects as those of the above-described embodiments.

  In the combined exhaust gas treatment apparatus of each embodiment described above, the polarity of the applied voltage of the high voltage pulse power supply 13 applied to the high voltage pulse gas treatment unit 10 and the direct current power supply to the catalyst type gas treatment unit 20 are applied. The polarity of the applied voltage is always opposite to the polarity. By changing the polarity in this way, it is possible to reliably treat the exhaust gas on the catalyst type gas processing unit 20 side by utilizing the polarity imparted to the exhaust gas on the high voltage pulse type gas processing unit 10 side.

  For example, when the applied voltage of the high voltage pulse power source 13 is positive, the applied voltage applied from the DC power source to the catalyst unit is negative. In this case, in the high voltage pulse gas processing unit, the exhaust gas can be plasma decomposed and at the same time the exhaust gas can have a polarity. Therefore, the exhaust gas treatment effect can be expected in both the high-voltage pulse type gas treatment unit and the catalyst type gas treatment unit, which is suitable for the treatment of a large volume of exhaust gas.

  Conversely, when the applied voltage of the high-voltage pulse power source 13 is negative, the applied voltage applied from the DC power source to the catalyst unit is positive. In this case, the high voltage pulse type gas processing unit 10 can be used to activate and polarize at least the exhaust gas, and the catalyst type gas processing unit 20 can be specialized for main exhaust gas processing. Therefore, when applying a voltage in this way, it is effective as a deodorizing device that dislikes the generation of ozone.

DESCRIPTION OF SYMBOLS 1 ... Gas inflow part, 2 ... Gas discharge part, 3 ... Exhaust gas, 10 ... High voltage pulse type gas processing part, 11 ... Line electrode, 12 ... External electrode, 13 ... High voltage pulse power supply, 14 ... Control circuit, 20 ... Catalytic gas processing unit, 22... Photocatalyst unit, 24... DC power supply, 25.

Claims (6)

  In a combined exhaust gas processing apparatus that processes exhaust gas using plasma and catalyst by pulse discharge, a high-voltage pulse gas processing unit that is installed in a previous stage on the gas inflow side and polarizes at least the exhaust gas; A combined exhaust gas treatment comprising a catalyst type gas treatment unit that is installed downstream of the high-voltage pulse type gas treatment unit and that adsorbs and oxidatively decomposes the exhaust gas. apparatus.   In a combined exhaust gas processing apparatus that processes exhaust gas using plasma and catalyst by pulse discharge, a high-voltage pulse gas processing unit that is installed in a previous stage on the gas inflow side and polarizes at least the exhaust gas; A catalyst type gas processing unit that is installed downstream of the high voltage pulse type gas processing unit and adsorbs the exhaust gas to oxidatively decompose, and the high voltage pulse type gas processing unit includes two electrodes. And a high-voltage pulse power source that connects one of the electrodes to the other and connects to the other electrode to apply intermittent high-voltage pulses, and the catalytic gas processing unit is disposed in the exhaust gas flow path. A catalyst unit; a DC power source that is connected to the catalyst unit and applies a DC voltage having a polarity opposite to the applied voltage of the high-voltage pulse power source; and an ultraviolet lamp that activates the catalyst unit. Features and That composite exhaust gas treatment apparatus.   3. The composite exhaust gas treatment apparatus according to claim 2, wherein the catalyst unit is configured by a charged plate type in which a catalyst is applied to a metal mesh plate (for example, using a wire mesh).   4. The electrode according to claim 2, wherein the two electrodes of the high-voltage pulse gas processing unit are constituted by a line electrode and a grounded cylindrical external electrode arranged coaxially with the line electrode. A combined exhaust gas treatment device.   4. The method according to claim 2, wherein the two electrodes of the high-voltage pulse gas processing unit are constituted by a line electrode and a ground-side arc-shaped external electrode that surrounds and opposes the line electrode. A combined exhaust gas treatment device.   4. The method according to claim 2, wherein the two electrodes of the high-voltage pulse gas processing unit are constituted by a line electrode and a flat plate-like external electrode on the ground side disposed opposite to the line electrode. Combined exhaust gas treatment device.

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