JP5142146B2 - Volatile organic compound processing equipment - Google Patents

Description

  The present invention relates to an apparatus for treating volatile organic compounds, and is particularly used for decomposing volatile organic compounds in gases discharged from factories and offices and releasing treated gases into the atmosphere. The present invention relates to a volatile organic compound processing apparatus.

  Volatile organic compounds (VOCs) are one of the causative substances of suspended particulate matter and photochemical oxidants. Due to the revised Air Pollution Control Law, which was enacted in 2006, factories and business establishments over a certain scale have become VOCs. As a result, there is a need to voluntarily suppress VOC emissions even for small and medium-sized businesses that are not subject to the regulations. The Tokai region where the applicants are located has more VOC emissions than other regions, and according to the 2004 data, it accounts for about one-fourth of the nationwide VOC emissions. In this region, the ratio of small and medium-sized establishments is also high. Therefore, in order to advance the voluntary efforts of small and medium-sized business establishments for the suppression of VOC emissions, a small and low running cost VOC processing apparatus that is easy to introduce in small and medium-sized business establishments is desired.

  Conventional VOC treatment apparatuses are roughly classified into apparatuses using an adsorption method, a chemical solution absorption method, a biodegradation method, a plasma decomposition method, and a combustion oxidation method (direct combustion type, heat storage combustion type, catalytic combustion type). Among them, in the combustion oxidation method, an apparatus using a burner as a heating means (for example, see Patent Document 1) and an apparatus using an electric heater (for example, see Patent Document 2) are generally used.

JP-A-11-212430 JP 2005-279570 A

  However, an adsorption method or chemical solution absorption method that requires replacement of adsorbents or chemicals and a running cost, a biodegradation method that requires labor and expense for biological maintenance, and a device that uses a large and expensive plasma decomposition method Was not suitable for small and medium-sized establishments. Further, in an apparatus using a burner as a heating means, there is a risk of flammable VOCs being ignited. In addition, an apparatus using an electric heater has a problem that heat efficiency is poor and heating takes time.

  Therefore, in view of the above circumstances, an object of the present invention is to provide a volatile organic compound processing apparatus that can be miniaturized and has a low running cost, and has high safety and high processing efficiency.

In order to solve the above-mentioned problems, the volatile organic compound processing apparatus according to the present invention is described as follows: “Electrically conductive heating element in which a communicating hole through which a gas flows is formed; A heating part for heating the gas flowing through the communication hole part by heat generation of the electrically conductive heating element by energization, and a catalyst body for reducing the oxidative decomposition temperature of the volatile organic compound, the heating part A catalyst portion that is provided on the downstream side of the gas flow and oxidatively decomposes a volatile organic compound contained in the gas heated by the heating portion, and the electrically conductive heating element is a porous electrically conductive ceramic A honeycomb structure including a plurality of cells partitioned by a plurality of partition walls arranged in a single direction, and the continuous pores in the cells and the porous partition walls are the communication holes. Phase And, no catalyst is supported on the partition walls of the porous "Ru Monodea.

The "electrically conductive heating element", used conductive ceramic, a semiconductor ceramics.

  The “communication hole portion through which the gas flows” can be configured by continuous pores when the electrically conductive heating element has a porous structure, or through holes provided in the electrically conductive heating element.

  “Volatile organic compounds” (hereinafter, sometimes simply referred to as “VOC”) are organic compounds that are gaseous when discharged or scattered into the atmosphere and are responsible for the formation of suspended particulate matter and oxidants. Substances specified by a government ordinance are excluded as substances that cannot be used, and examples include toluene, xylene, dichloromethane, ethylbenzene, benzene, acetone, methyl ethyl ketone, methyl isobutyl ketone, methanol, isopropyl alcohol, ethyl acetate, and butyl acetate. In particular, toluene and xylene are frequently used as solvents in factories and offices related to printing and painting, and have large emissions.

  “Catalysts that lower the oxidative decomposition temperature of volatile organic compounds” include platinum, palladium, rhodium, gold, iridium, ruthenium, and other metal catalysts, cerium oxide, zirconium oxide, titanium oxide, tin oxide, manganese oxide, and oxidation. A metal oxide catalyst such as tantalum can be used. Alternatively, a plurality of metal catalysts, a plurality of metal oxide catalysts, or a composite catalyst in which a metal catalyst and a metal oxide catalyst are combined can be used. In addition, although the oxidative decomposition temperature of VOC is 650-800 degreeC, it can be oxidatively decomposed at 200-400 degreeC by the effect | action of said catalyst.

  Since the “catalyst part” is “provided on the downstream side of the gas flow from the heating part”, the heating part and the catalyst part are configured separately.

  The structure of the catalyst body includes a structure in which the catalyst is supported on a porous body through which gas can flow, a structure in which gas is circulated through continuous pores and through holes provided in the catalyst itself, and a tubular or cylindrical gas through which gas is circulated. The structure filled with the catalyst can be illustrated, leaving the space | gap which can distribute | circulate gas in the inside of a flow path.

  With the above configuration, according to the present invention, an untreated gas containing VOC discharged from a factory or office in the communicating hole portion of the electrically conductive heating element in a state where the electrically conductive heating element is heated by energization The untreated gas can be heated by circulating the gas. And the untreated gas heated by the heating part provided with an electroconductive heat generating body flows in into the catalyst part provided in the downstream, and receives the effect | action of a catalyst. Therefore, in the heating section, the temperature of the untreated gas is raised to the oxidative decomposition temperature of VOC in the presence of the catalyst, and then introduced into the catalyst section to decompose the VOC at a lower temperature than in the case of oxidative decomposition by direct combustion. be able to. And in this invention, the structure which distribute | circulates gas does not heat from the exterior by external heat sources, such as a heater and a burner, but the structure itself which distribute | circulates gas heat | fever-generates by electricity supply. Thereby, electrical energy can be efficiently used for heating the untreated gas.

  Here, it can also be assumed that the catalyst body has a structure in which the catalyst is supported in the communication hole portion of the electrically conductive heating element. However, in this case, the untreated gas passes through the catalyst body before it is sufficiently heated, and there is a risk that the oxidative decomposition of VOC will be insufficient. On the other hand, in the present invention, the heating unit and the catalyst unit are configured separately, and the temperature of the untreated gas can be sufficiently increased in advance in the heating unit and then introduced into the downstream catalyst unit. It is possible to sufficiently oxidatively decompose VOC at a low temperature.

  Moreover, in this invention, since there is no possibility of igniting VOC like the conventional apparatus which uses a burner, it is a highly safe apparatus. In addition, there are no parts that need to be replaced regularly as in the conventional device using the adsorption method or chemical solution absorption method, and there is no problem in the maintenance of organisms as in the conventional device using the biodegradation method. Is inexpensive and easy to handle. In addition, since it is an extremely simple configuration mainly including an electrically conductive heating element and a catalyst body, the entire apparatus can be reduced in size.

  The volatile organic compound processing apparatus according to the present invention includes, in addition to the above configuration, “the heating unit includes a steel wool layer interposed between the electrode and the outer surface of the electrically conductive heating element”. can do.

  With the above configuration, according to the present invention, the electrode and the electrically conductive heating element can be electrically connected at many contact points with the steel wool. This makes it easy to energize the electrically conductive heating element regardless of the surface state such as whether or not the outer surface of the electrically conductive heating element is smooth. In addition, by using a very simple configuration of steel wool, the above-described effects can be obtained without cost.

  In addition to the above configuration, the volatile organic compound processing apparatus according to the present invention includes "the heating unit includes a spring member that biases the electrode in a direction in which the electrode is pressed against the electrically conductive heating element". it can.

  With the above configuration, according to the present invention, the degree of adhesion between the electrode and the electrically conductive heating element can be increased by the spring member, and therefore it is easy to energize the electrically conductive heating element. In addition, thermal expansion of the electrically conductive heating element can be absorbed by elastic deformation of the spring member.

  In addition to the above-described configuration, the volatile organic compound processing apparatus according to the present invention is “the electrically conductive heating element is a porous body, and the heating unit is provided on the upstream side of the gas flow from the electrically conductive heating element. And a gas flow path dispersing member that disperses the gas flow path ”. The continuous pores in the porous body correspond to the above “communication hole portion”.

  “Gas flow path dispersion member” includes a flat plate member having a large number of small through holes for circulating gas, a funnel that expands the gas flow path along a funnel-shaped surface, along fins and blades. A member that guides the flow of gas can be exemplified.

  Since the porous body has a large number of communicating holes, the gas can be circulated through the numerous communicating holes to heat the gas efficiently. However, if the gas flows only in a part of the many communicating holes, the above-mentioned advantage that the electrically conductive heating element is porous cannot be exhibited. For example, there is a case where the gas circulates with high straightness although the cross-sectional area of the electrically conductive heating element is larger than the diameter of the flow path for introducing the gas into the heating unit. In contrast, in the present invention, the gas flow path before flowing into the electrically conductive heating element can be dispersed by providing the gas flow path dispersing member. As a result, even if the cross-sectional area of the electrically conductive heating element is large, it is easy to distribute the gas to the porous heating element as a whole, and the gas can be efficiently heated by effectively using the heat generated by the entire heating element. Can do.

  In addition, fine dust and particulate matter contained in the untreated gas can be removed by the filtering action of the electrically conductive heating element that is a porous body. Here, if the catalyst is supported on the porous electrically conductive heating element, the substance collected by the filtering action may cover the surface of the catalyst, and the action of the catalyst may not be sufficiently obtained. is there. On the other hand, in the present invention, since the catalyst part has a separate structure from the heating part, the catalyst action can be sufficiently exhibited without being affected by the filtering action of the porous body.

  The volatile organic compound processing apparatus according to the present invention may be “a plurality of the electrically conductive heating elements are provided, and two or more of them are electrically connected in series”.

  For example, when compared with an electrically conductive heating element having the same volume, the distance through which electricity flows through the electrically conductive heating element becomes longer and the electrical resistance increases when divided into a plurality and connected in series. Therefore, even when the electrical resistance value of the electrically conductive heating element is small, a large amount of heat generation can be obtained while preventing the current value from becoming excessive. This makes it possible to heat the gas with a large calorific value using a commercial power supply without requiring special equipment. Therefore, with the above-described configuration, the volatile organic compound processing apparatus according to the present invention can be an apparatus that can be easily introduced for small and medium-sized businesses.

  As described above, as an effect of the present invention, it is possible to provide a volatile organic compound processing apparatus that can be downsized and has a low running cost, and that has high safety and high processing efficiency.

  Hereinafter, a volatile organic compound processing apparatus according to the best embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is a configuration diagram showing a schematic configuration of the volatile organic compound processing apparatus of the present embodiment, and FIG. 2 is a front view of a main part of the volatile organic compound processing apparatus of FIG. 3 is a rear view of the main part of the volatile organic compound processing apparatus of FIG. 1 (viewed from the catalyst part side), and FIG. 4 is a sectional view taken along line XX in FIG. 5 is a cross-sectional view taken along line YY in FIG. 2, and FIG. 6 is an explanatory view for explaining gas dispersion.

  The volatile organic compound processing apparatus 1 of the present embodiment (hereinafter simply referred to as “VOC processing apparatus 1”) includes an electrically conductive heating element 2 (hereinafter referred to as “not shown”) in which a communication hole (not shown) through which gas flows is formed. A heating unit 20 that includes an electrode 21 for energizing the heating element 2 and that heats the gas flowing through the communication hole by the heat generated by the energization, and a volatile organic material. A catalyst body 30 that includes a catalyst body 3 that lowers the oxidative decomposition temperature of the compound, and that is provided downstream of the heating section 20 in the gas flow and oxidatively decomposes a volatile organic compound contained in the gas heated by the heating section 20; It has.

  Here, the heating element 2 of the present embodiment is a honeycomb structure including a plurality of cells made of porous silicon carbide ceramics and partitioned by a plurality of partition walls extending in a single direction. It is constituted by. The continuous pores in the cell and the porous partition wall of the present embodiment correspond to the “communication hole portion” of the present invention.

  Further, the VOC treatment apparatus 1 includes a gas introduction path 8 that leads gas from the suction port 6 to the heating unit 20, a gas discharge path 9 that leads gas from the catalyst unit 30 to the discharge port 7, and a gas that flows through the gas introduction path 8. And a heat exchanger 4 for exchanging heat between the gas flowing through the gas discharge passage 9. Furthermore, a fan 18 that sucks gas by driving a motor (not shown) is attached to the suction port 6. In addition, although detailed illustration is abbreviate | omitted, the heat exchanger 4 becomes a structure which wound the gas discharge path 9 around the gas introduction path 8. FIG.

  In the heating unit 20, as shown mainly in FIG. 4, two rows of heating elements 2 are provided in the gas flow direction (shown, the direction from the bottom to the top of the drawing), and the direction substantially orthogonal to the gas flow direction. In addition, three rows of heating elements 2 are provided. And as mainly shown in FIG. 2, each row | line | column has the three-stage structure on which the three heat generating bodies 2 were laminated | stacked up and down. In the two rows in the gas flow direction, as shown in FIG. 5, the lowermost heating elements 2 are connected to each other by an electrically conductive conduction portion 22. The conduction part 22 of the present embodiment uses a stainless steel plate. Further, of the two rows in the gas flow direction, one of the positive electrode 21a and the negative electrode 21a is attached to the upper surface of the uppermost heating element 2 on the upstream side, and the uppermost heating element 2 in the downstream row. A counter electrode 21b is attached to the upper surface.

  With such a configuration, a total of six heating elements 2 in two rows in the gas flow direction are electrically connected in series by energizing the electrodes 21a and 21b. And in this embodiment, three of the row | line | column where the six heat generating bodies 2 were connected in series are connected in parallel. Hereinafter, when it is not necessary to distinguish between the electrode 21a and the electrode 21b, they will be collectively referred to as the electrode 21.

  Steel wool layers 23 are provided between the electrode 21 and the heating element 2, between the adjacent heating elements 2, and between the heating element 2 and the conduction portion 22. Further, a through hole is formed in the top plate 29t of the casing 29 of the heating unit 20, and a bolt 25 for pushing the electrode 21 down and fixing it to the heating element 2 is inserted into the through hole. . Further, a substantially U-shaped support plate 26 is fixed downward on the top surface of the top plate 29t, and a coil-shaped spring member 27 is fastened to the support plate 26 from below. The upper portion of the shaft portion of the bolt 25 is inserted into the spring member 27 from below, and a flange portion provided along the outer periphery of the shaft portion is in contact with the bottom surface of the spring member 27. With such a configuration, the spring member 27 is compressed between the flange portion of the bolt 25 and the support plate 26, and is attached in a direction in which the electrode 21 is pushed down via the bolt 25, that is, in a direction in which the electrode 21 is pressed against the heating element 2. It is fast. In order to prevent the electrode 21a and the electrode 21b from being short-circuited via the bolt 25, the top plate 29t, or the like, a heat insulating insulating layer 24 is interposed between the bolt 25 and the electrode 21.

  Further, as shown mainly in FIG. 4, a heat insulating insulating layer 24 is filled between the heating element 2 and the casing 29 and between the heating elements 2 adjacent to each other in a direction substantially orthogonal to the gas flow direction. Yes. On the other hand, in the gas flow direction, a heat insulating insulating layer is not filled between the heat generating element 2 and the heat generating element 2, and a space 28 is formed.

  In the catalyst unit 30, as shown mainly in FIG. 5, the catalyst body 3 is accommodated in the casing 39, and the outer surface of the catalyst body 3 excluding the cross section through which the gas is circulated is entirely covered with a heat insulating material 34. Is covered. The catalyst body 3 of the present embodiment is formed by supporting a noble metal catalyst on a porous cordierite ceramic honeycomb structure.

  Next, gas processing in the VOC processing apparatus 1 of the present embodiment will be described. First, an untreated gas containing VOC discharged from a factory or business place is sucked from the suction port 6 by the fan 18, then flows through the gas introduction path 8 and is introduced into the heating unit 20. At this time, in the heating unit 20, the heating element 2 generates heat by energizing the electrodes 21a and 21b. Therefore, the untreated gas is heated when passing through the heating element 2 that is a honeycomb structure.

  In the heating unit 20 of the present embodiment, the power generators 2 are provided in two rows in the gas flow direction, and a space 28 is formed between them, so that the gas that has passed through the heating elements 2 in the upstream row is downstream. Before it flows into the heating elements 2 in the side row, it hits the front surface and easily diffuses in the space 28 (see FIG. 6). Thereby, the gas introduced into the heating part 20 from the end part of the gas introduction path 8 is prevented from passing through only a part of the heating element 2. In the present embodiment, the power supply to the heating element 2 is adjusted so that the heating element 2 is maintained at about 300 ° C.

  In addition, since the heating element 2 is a honeycomb structure in which a plurality of cells are arranged, the gas is efficiently heated by the partition walls that generate heat when flowing through the cells. In addition, since the heating element 2 is porous, if fine dust or particulate matter is present in the gas, it is collected in the pores of the partition walls.

  The untreated gas heated by passing through the heating element 2 then flows into the catalyst unit 30 and passes through the catalyst body 3 which is a honeycomb structure on which the catalyst is supported. At this time, since the untreated gas has already been heated to about 300 ° C. in the heating unit 30 so that the VOC can be oxidatively decomposed in the presence of the catalyst, VOCs are oxidatively decomposed at a lower temperature than when oxidatively decomposed by direct combustion.

  Then, the treated gas after the oxidative decomposition of the VOC flows through the gas discharge passage 9 and enters the heat exchanger 4, where it heats the untreated gas flowing through the gas introduction passage 8 to become a low temperature, and is discharged. It is discharged from the outlet 7 into the outside air.

  As described above, according to the VOC processing apparatus 1 of the present embodiment, the heating element 2 itself is a structure in which the gas is circulated instead of being heated from the outside by an external heat source such as a heater or a burner. Since the heat is generated, the gas that circulates with high energy efficiency can be heated. In addition, since the heating element 2 and the catalyst body 3 have a simple configuration, the entire apparatus can be reduced in size.

  Further, in the present embodiment, the catalyst is not supported on the porous silicon carbide ceramics which is the heating element 2, but the catalyst unit 30 is arranged downstream of the heating unit 20 as a configuration separate from the heating unit 20. Is provided. Therefore, the temperature of the untreated gas can be increased in advance by the heating unit 20 to 300 ° C. sufficient for the oxidative decomposition of VOC in the presence of the catalyst, and then introduced into the catalyst unit 30. As a result, it is possible to fully oxidize and decompose VOC at a low temperature by fully exerting the action of the catalyst.

  In addition, fine dust and particulate matter contained in the untreated gas are collected in the heating element 2 by the filtering action of the porous honeycomb structure. At this time, the catalyst body 3 and the heating element 2 are configured separately, and the catalyst is not supported on the honeycomb structure which is the heating element 2, so that the catalyst is covered with the collected substance. There is no. Thereby, the catalyst body 3 can be used over a long period of time.

  Further, the silicon carbide ceramic used as the heating element 2 has high strength and excellent heat resistance and thermal shock resistance. Therefore, it is suitable as the heating element 2 in which heating and cooling are repeated with use. In addition, since silicon carbide ceramics are excellent in oxidation resistance and corrosion resistance, they are suitable as a configuration for heating an untreated gas containing various VOCs. In addition, since silicon carbide ceramics has a high thermal conductivity and quickly rises in temperature, the raw gas can be efficiently heated by the heat generated by energization.

  Further, since the steel wool layer 23 is interposed between the electrode 21 and the heating element 2, the electrode 21 and the heating element 2 are independent of the surface state such as whether the outer surface of the heating element 2 is smooth or not. Are in close contact with each other at many contact points, and the heating element 2 is easily energized. Furthermore, since the steel wool layer 23 is interposed between the adjacent heating elements 2 and between the heating element 2 and the conduction portion 22, it is easy to conduct electricity between these components, and the six heating elements are surely provided. 2 can be electrically connected.

  In addition, a force pressing downward by the spring member 27 acts on the heating elements 2 stacked in three stages. Therefore, the steel wool layer 23 disposed between the electrode 21 and the heating element 2, between the heating elements 2 adjacent to each other in the vertical direction, and between the heating element 2 and the conducting portion 22 is also compressed by the pressing force of the spring member 27. Has been. Thereby, the electrical contact points by steel wool become many, and the electrical connection action by the steel wool layer 23 can be exhibited more effectively.

  Further, even if the heating element 2 and the like are thermally expanded by heating, the thermal expansion is absorbed by the spring member 27. Thereby, a thermal stress is relieved between each structure of the heating part 20, and generation | occurrence | production of a distortion, a crack, etc. can be prevented effectively.

  In addition, the silicon carbide ceramic used for the heating element 2 in the present embodiment has NTC characteristics in which the electric resistance decreases as the temperature rises. In this embodiment, six heating elements 2 are connected in series. This increases the electrical resistance value. Thereby, a large calorific value can be obtained using a commercial power supply without making the current value excessive. Therefore, the VOC processing apparatus 1 of the present embodiment that can heat the gas with a large calorific value without requiring any special equipment is suitable as an apparatus introduced in a small and medium-sized office.

  Moreover, since the VOC processing apparatus 1 of this embodiment is equipped with the heat exchanger 4, it can utilize the exhaust heat of processed gas effectively, can introduce | transduce into a heating part 30 after heating an untreated gas beforehand. it can. Thereby, the energization amount to the heat generating body 2 can be reduced, and running cost can be suppressed. In addition, the treated gas can be prevented from being discharged into the atmosphere in a high temperature state and adversely affecting the environment.

  In addition to the above-described configuration, the VOC processing apparatus 1 according to the present embodiment includes a gas flow path dispersion member that disperses the gas flow path in the heating unit 20 on the upstream side of the gas flow from the heating element 2. Can do. For example, as shown in FIG. 6, a dispersion plate 41 having a large number of small through holes can be provided in the vicinity of the end of the gas introduction path 8. Further, a dispersion blade 42 in which a plurality of blades are provided on the outer surface of the base body having a conical section can be provided in the vicinity of the front surface of the heating element 2 on the downstream side. Here, the dispersion plate 41 and the dispersion blades 42 both correspond to “gas flow path dispersion members”.

  With the above-described configuration, the gas flowing out from the end of the gas introduction path 8 first disperses in various directions by passing through a large number of through holes of the dispersion plate 41. The dispersed gas is then guided and distributed by the dispersion blades 42, and the diameter of the gas flow passage is expanded. As a result, even when the total cross-sectional area of the plurality of heating elements 2 arranged in a row is larger than the cross-sectional area of the gas introduction path 8, the gas is uniformly passed through the entire heating element 2 having the honeycomb structure to generate heat. The gas can be heated by effectively utilizing the heat generated by the entire body 2.

  Using the VOC processing apparatus of this embodiment, exhaust gas from the factory was actually processed, and the processing efficiency of VOC was examined. A total of nine silicon carbide ceramic honeycomb structures (porosity of about 58%, average pore diameter of about 19 μm, cell density of 169 cpsi, dimensions of about 90 mm × 90 mm × 30 mm) were used as the heating elements. As described with reference to FIG. 4 and the like, two rows are arranged in the gas flow direction, three rows in the direction substantially perpendicular to the gas flow direction, and three rows in the up and down direction, and two rows in the gas flow direction. Three rows were connected in series, and three rows substantially perpendicular to the gas flow direction were connected in parallel. As the catalyst body, four cordierite honeycomb structures (porosity of 60 to 70%, average pore diameter of about 20 μm, cell density of 300 cpsi, dimensions of about 150 mm × 150 mm × 50 mm) supported with a noble metal catalyst, Two were placed one above the other on the top, bottom, left and right. The overall dimensions of the VOC decomposition apparatus were approximately width 1.8 m × depth 0.9 m × height 1.3 m, and the total weight was about 300 kg.

  Collect the exhaust gas from the gravure printing machine for 20 minutes at the printing factory, and also collect the gas after processing the exhaust gas with the VOC treatment device for 20 minutes, and measure the VOC concentration in each gas before and after the treatment. The processing efficiency was determined by comparing the VOC concentration. The measurement was performed several times, and the average value of the processing efficiency was calculated. In addition, measurements were made for comparison when different types of precious metal catalysts were used. As the noble metal catalyst, two types of (A) palladium catalyst (NHX-724 manufactured by JGC Universal) and (B) platinum catalyst (NH-124 manufactured by JGC Universal) were used. The measurement results are shown in Table 1. The VOC treatment efficiency in Table 1 is a summary of the results for VOC components whose concentration before treatment was 1 ppm or more.

  The VOC processing apparatus of this example was smaller than the conventional apparatus and could be manufactured at low cost, but the total VOC processing efficiency was about 80%, which was a practical processing capacity. Further, when palladium was used as the catalyst, the temperature in the catalyst part was also maintained at 250 to 300 ° C. by raising the exhaust gas temperature to about 300 ° C. in the heating part. On the other hand, when a platinum catalyst was used, the discharge temperature from the catalyst part was higher than the temperature of the gas introduced into the catalyst part, which was considered to be due to the reaction heat due to oxidative decomposition of VOC. From this, after the decomposition reaction of VOC in the catalyst portion has started, even if the temperature of the heating portion is controlled to be lowered by several tens of degrees centigrade by measuring and feeding back the temperature of the catalyst portion, It was suggested that the decomposition reaction of VOC can be carried out continuously. By controlling the temperature of the heating unit in this way, energy consumption can be saved and VOC processing can be performed.

  Further, in the VOC processing apparatus of the present embodiment, the temperature of the gas sucked into the apparatus at room temperature is raised to a high temperature of 150 to 200 ° C. in advance by exchanging heat between the exhaust gas and the introduced gas. Could be introduced into the heating section.

  The present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the present invention as described below. And design changes are possible.

  For example, in the above embodiment, the case where six rows of two heating elements in the gas flow direction are connected in series is exemplified, but the present invention is not limited to this, and the method of connecting the heating elements is the kind of the heating element. It can be appropriately changed depending on (electric resistance value), size, and the like. In particular, in the above-described embodiment, two rows in which the three heating elements 2 are stacked one above the other are separated by a space and are connected by a conductive portion. It can be easily changed to a configuration connected in parallel rather than in series. That is, as shown in FIG. 7, in the row of three heating elements stacked vertically, the three heating elements are connected in series by attaching the electrodes 21a and 21b to the uppermost and lowermost heating elements, respectively. Each column can be connected in parallel to each other column.

  Moreover, although the case where one catalyst body was provided in the catalyst part was illustrated, it is not limited to this, It can be set as the structure by which the several catalyst body was arranged in the gas distribution direction. In that case, the type of catalyst may be the same or different.

  In addition, the catalyst body is exemplified by a catalyst in which a catalyst is supported on a porous body. However, the present invention is not limited to this. For example, the catalyst itself such as a foam metal can be used as the porous structure.

It is a block diagram which shows schematic structure of the volatile organic compound processing apparatus of this embodiment. It is a front view (figure seen from the heating part side) of the principal part of the volatile organic compound processing apparatus of FIG. It is a rear view (figure seen from the catalyst part side) of the principal part of the volatile organic compound processing apparatus of FIG. It is the XX sectional view taken on the line in FIG. It is the YY sectional view taken on the line in FIG. It is explanatory drawing explaining dispersion | distribution of gas. It is a front view (figure seen from the heating part side) of the volatile organic compound processing apparatus of other embodiment.

Explanation of symbols

1 VOC treatment equipment (volatile organic compound treatment equipment)
2 Heating element (electrically conductive heating element)
3 catalyst body 20 heating part 21, 21a, 21b electrode 23 steel wool layer 27 spring member 30 catalyst part 41 dispersion plate (gas flow path dispersion member)
42 Dispersion blade (gas flow path dispersion member)

Claims (4)

An electrically conductive heating element in which a communicating hole for circulating gas is formed, and an electrode for energizing the electrically conductive heating element. A heating unit for heating the circulating gas;
A catalyst unit that includes a catalyst body that lowers the oxidative decomposition temperature of the volatile organic compound, and that is provided on the downstream side of the gas flow from the heating unit and oxidatively decomposes the volatile organic compound contained in the gas heated by the heating unit; equipped with,
The heating unit includes a steel wool layer interposed between the electrode and the outer surface of the electrically conductive heating element,
The electrically conductive heating element is a honeycomb structure comprising a plurality of cells made of porous electrically conductive ceramics and partitioned by a plurality of partition walls extending in a single direction. A volatile organic compound treatment apparatus, wherein continuous pores in a cell and a porous partition wall correspond to the communication hole portion, and a catalyst is not supported on the porous partition wall . The volatile organic compound processing apparatus according to claim 1, wherein the heating unit includes a spring member that urges the electrode in a direction in which the electrode is pressed against the electrically conductive heating element. The said heating part is provided in the upstream of the gas distribution | circulation from the said electrically conductive heat generating body, The gas flow path dispersion | distribution member which distributes the flow path of gas is provided, The claim 1 or Claim 2 characterized by the above-mentioned. Volatile organic compound processing equipment. The plurality of electrically conductive heating elements are provided, and two or more of them are electrically connected in series. Volatile organic compound processing equipment.

Images