JP6409222B2 - Method for producing catalyst-carrying block - Google Patents

Description

The present invention, volatile organic compounds (VOC: Volatile Organic Compound), relates to the purification apparatus used for purifying the gas containing harmful substances such as an exhaust gas, and a method of manufacturing a catalyst supporting block.

  The present inventor has proposed a method utilizing the catalytic activity of a heated oxide semiconductor as a method for decomposing and purifying a gas such as plastic or VOC (Patent Document 1). When an oxide semiconductor such as chromium oxide or titanium oxide is heated to about 350 to 500 ° C., a large amount of holes are generated, and the object to be decomposed is cut into small molecules by the strong oxidizing power of the holes. Thus, these small molecules react with oxygen in the air and are completely decomposed into water and carbon dioxide (Non-patent Documents 1 and 2).

  Further, the present inventor, as a purification device using an oxide semiconductor, a catalyst part formed by supporting an oxide semiconductor on a base material having air permeability made of a honeycomb or a mesh-like porous body, and the catalyst part. The apparatus provided with the heater to heat was proposed (patent document 2). In this purifying device, the catalyst parts are arranged in a plurality of stages, and a gas to be treated sequentially passes through the catalyst parts in a state where the catalyst parts are heated by arranging heaters between the catalyst parts. The gas is configured to be purified.

Japanese Patent No. 4517146 JP 2010-214359 A

T. Shinbara, T. Makino, K. Matsumoto and J. Mizuguchi: Completedecomposition of polymers by means of thermally generated holes at hightemperatures in titanium dioxide and its decomposition mechanism, J. Appl. Phys98, 044909 1-5 (2005) Hitoshi Mizuguchi: Complete decomposition, recycling technology and processing technology of FRP by thermal activation of semiconductors 47, 37-47 (2012)

The purification device described above has an advantage that a purification device can be easily constructed according to the amount of gas to be processed and the type of gas to be processed by combining the catalyst unit and the heater into a unit and combining the units. is there. Further, by arranging the heater with the catalyst portion interposed therebetween, the catalyst portion is heated uniformly and efficiently by the heaters positioned above and below.
However, in this purification device, the catalyst part and the heater are separated, and it is necessary to secure the installation space for each of them, so there is a problem that it is constrained to reduce the size of the purification device. . Further, in the conventional apparatus, heat from the heater escapes in the lateral direction in addition to the heating of the upper and lower catalyst parts, and there is a problem that the thermal efficiency is insufficient.

  This method of purifying gases using the catalytic activity of oxide semiconductors is much smaller than conventional combustion methods, but if it can be further improved in thermal efficiency and downsized, it can be installed in equipment that generates harmful substances. In this way, it is possible to prevent harmful substances from being discharged into the environment, and the use of the purification apparatus can be greatly expanded.

It is an object of the present invention to provide a gas purification device that can effectively purify a gas containing harmful substances by utilizing the catalytic action of an oxide semiconductor, and enables use in various applications. And it aims at providing the manufacturing method of the catalyst support block used for the purification apparatus of gas.

In the method for producing a catalyst carrying block according to the present invention, the catalyst carrying block is provided with a housing portion formed in a groove shape that matches the planar shape of the heater to be housed, and the catalyst carried on the block. Is an oxide semiconductor, and when heated to a temperature region where a large amount of holes and electrons are generated by interband transition of the oxide semiconductor, the organic compound in contact with the oxide semiconductor is A process of forming a foam in accordance with the outer shape of the catalyst-carrying block as a manufacturing process, and a cross-sectional shape of a heater accommodated in the catalyst-carrying block on the molded foam A heating element made of a metal wire bent to match the heating is swept while heating, and the foam in the region through which the heating element has passed is removed, so that the heater is accommodated in the foam. A step of forming a groove shape to be a part, and after impregnating a ceramic slurry into the foam formed with the groove shape, the foam is dried and fired to decompose and remove the foam, The method includes a step of forming a porous body made of a ceramic component of the slurry, and a step of supporting the oxide semiconductor on the porous body.
A gas purification apparatus according to the present invention includes a catalyst supporting block in which an oxide semiconductor is supported on a base material made of the catalyst supporting block porous body manufactured by the catalyst supporting block manufacturing method, and a storage for storing the catalyst supporting block. A container and a heater for heating the catalyst carrying block, wherein the catalyst carrying block is provided with a heater accommodating portion (heater insertion hole), and the heater is inserted and mounted in the heater accommodating portion. Features.
The substrate made of a porous material is a material formed in a form in which a gas passage such as a honeycomb structure or a three-dimensional network structure is very complicated, and is a solid solution such as alumina, magnesia, silica, or zeolite, It is a sintered body such as silicon carbide.

The oxide semiconductor to be supported on the base material of the catalyst support block is a stable substance even at high temperatures and even in an oxygen atmosphere at the time of decomposition of the compound, and examples thereof include a substance represented by the following chemical formula: However, it is not limited to these. _{BeO, MgO, CaO, SrO,} BaO, CeO 2, TiO 2, ZrO 2, V 2 O 5, Y 2 O 3, Y 2 O 2 S, Nb 2 O 5, Ta 2 O 5, MoO 3, WO 3 _{, MnO 2, Fe 2 O 3} , Fe 3 O 4, MgFe 2 O 4, NiFe 2 O 4, ZnFe 2 O 4, ZnCo 2 O 4, ZnO, CdO, MgAl 2 O 4, ZnAl 2 O 4, Tl 2 O ₃ , In ₂ O ₃ , SnO ₂ , PbO ₂ , UO ₂ , Cr ₂ O ₃ , MgCr ₂ O ₄ , FeCrO ₄ , CoCrO ₄ , ZnCr ₂ O ₄ , WO ₂ , MnO, Mn ₃ O ₄ , Mn ₂ O ₃ , FeO, NiO, CoO, Co ₃ O ₄ , PdO, CuO, Cu ₂ O, Ag ₂ O, CoAl ₂ O ₄ , NiAl ₂ O ₄ , Tl ₂ O, GeO, PbO, T iO, Ti ₂ O ₃ , VO, MoO ₂ , IrO ₂ , RuO ₂ .

  The above-described mechanism for completely decomposing VOC and the like is summarized as follows (see Non-Patent Document 1 and Non-Patent Document 2). First, the thermal activity of a semiconductor is a phenomenon in which a remarkable catalytic effect appears suddenly when a semiconductor that does not show a catalytic effect at room temperature is heated to 350-500 ° C. When the semiconductor is thermally excited (that is, heated), electrons in the valence band are excited to the conduction band, and a large number of holes (holes) from which electrons are removed are generated in the valence band. These holes have the property that they want the electrons to return quickly and return to their original stable state. That is, the force which pulls an electron is strong, in other words, it has a strong oxidizing power. Using the strong oxidizing power of the holes, bond electrons are taken away from a compound to be decomposed (for example, a polymer), and a cation radical is generated in the polymer. This unstable radical propagates in the polymer at a temperature of 350-500 ° C, destabilizes the whole polymer, induces radical cleavage, and makes the macromolecule small. As a result, the trimmed molecules such as ethylene and propane react with oxygen in the air to become carbon dioxide and water by a complete combustion reaction. In this way, the decomposition process consists of three processes: large-scale hole generation, small molecule formation by radical cleavage, and complete combustion.

The catalyst carrying block used for the purification processing unit can be provided with a heater containing portion formed in a single block shape, and the heater can be mounted, or a plurality of catalyst carrying blocks can be combined, It can also be configured and used in the form of a block as a whole.
When a plurality of catalyst support blocks are used in combination with each other in contact with each other, a concave groove is provided on both contact surfaces (combination surfaces) of the catalyst support block so that a heater accommodating portion (heater insertion hole) is provided. It can also be formed, or a concave groove can be provided at a depth at which the heater is buried in only one contact surface to serve as a heater accommodating portion.
When a plurality of catalyst supporting blocks are used in combination, there is an advantage that the arrangement of the heater can be adjusted simply by changing the way of combining the catalyst supporting blocks, and it can be easily adjusted according to the processing air volume. When the arrangement of the heaters is determined, it is also possible to mount the heater by providing a heater accommodating portion in one block-shaped catalyst supporting block without combining the catalyst supporting blocks.

When mounting a heater with a curved planar shape such as an M-shaped heater, it is effective to combine the catalyst support block and provide a heater housing (heater insertion hole) on the combined surface of the catalyst support block. is there.
By providing a heater accommodating portion in the catalyst supporting block and heating the catalyst supporting block by bringing the heater into direct contact with the catalyst supporting block, the catalyst supporting block can be uniformly and efficiently heated. The heater accommodating portion is provided in a direction in which the longitudinal direction of the accommodating portion is orthogonal to the conveying direction of the gas to be processed passing through the catalyst supporting block, thereby preventing the catalyst supporting block from being disturbed. Heating can be performed uniformly and efficiently, and the gas to be treated can be effectively purified.

Further, a sealing property is provided between the side surface of the catalyst support block and the inner side surface of the storage container to prevent leakage of the gas to be processed from between the side surface of the catalyst support block and the inner side surface of the storage container. By interposing the heat insulating material, the gas to be treated is prevented from leaking from between the side surface of the catalyst carrying block and the inner side surface of the storage container, and the gas to be treated can be reliably purified and discharged. .
In addition, by providing a heat insulating material that blocks heat conduction from the storage container to the outside on the outer periphery of the storage container, the catalyst-carrying block stored in the storage container can be efficiently heated by the heater, The purification device can be used safely.

  The method for producing the catalyst supporting block constituting the gas purification device includes a step of forming a foam according to the outer shape of the catalyst supporting block, and a cross-sectional shape of the heater accommodated in the catalyst supporting block on the formed foam A heating element made of a metal wire having a bent shape adapted to the shape of the wire is swept while being heated, and the foam in the region through which the heating element has passed is removed, thereby forming a groove shape serving as a housing portion for the heater in the foam. And a step of impregnating the ceramic slurry in the foam in which the groove shape is formed, and then drying and firing the foam to decompose and remove the foam and to form a porous material composed of the ceramic component of the slurry. A manufacturing method including a step of forming a body and a step of supporting an oxide semiconductor on the porous body is effective in that the housing portion of the heater can be easily and reliably formed.

  According to the gas purification apparatus of the present invention, the catalyst supporting block is provided with the heater accommodating portion, and the heater accommodating portion is accommodated in the heater supporting portion, so that the catalyst supporting block can be efficiently heated. Furthermore, since the catalyst carrying block and the heater are arranged in a compact manner, the purification device can be downsized, and harmful substances can be effectively purified.

It is an external view of the purification process part of a purification apparatus. It is the top view (a) and perspective view (b) of the catalyst support block arrange | positioned at a process part. It is an assembly perspective view of the process part of a purification apparatus. It is the photograph which shows the state which looked at the state which accommodated the catalyst carrying block from the end surface direction of the case part. It is sectional drawing (a) and a top view (b) of the catalyst support block equipped with the M-shaped heater. It is an example of the M-shaped heater attached to a catalyst carrying block. It is a figure which shows the manufacturing process of a catalyst carrying block. It is a photograph of the catalyst unit which consists of a ceramic porous body and a heater.

  FIG. 1 is an external view of a purification processing unit 10 which is a main component part of an embodiment of a gas purification apparatus according to the present invention. The purification processing unit 10 includes a storage container 12 that stores a catalyst carrying block 20 that purifies a gas to be processed, and ducts 14 a and 14 b connected to the storage container 12. The storage container 12 is assembled into a rectangular tube shape using a stainless plate, and the catalyst support block 20 is stored so as to substantially fill the storage space of the storage container 12. Flange 12a is provided on both side edges on the opening side of the storage container 12, and ducts 14a and 14b are connected to the flange 12a, and the inside of the ducts 14a and 14b and the storage container 12 is a communication space.

FIG. 2 shows the catalyst support block 20 stored in the storage container 12. 2A is a plan view of the catalyst carrying block 20 stored in the storage container 12, and FIG. 2B is a perspective view. As shown in FIG. 2, the catalyst carrying blocks 20 are stored in the storage container 12 with their end faces in contact with each other and aligned.
In the illustrated example, four catalyst support blocks 20 are stored in the storage container 12. One catalyst support block 20 has a thickness of 30 mm, a height of 50 mm, and a lateral width of 73 mm. In a state where four catalyst support blocks 20 are arranged, the block shape is a block having a width of 73 mm, a height of 50 mm, and a length (gas flow direction) of 120 mm. The catalyst support block 20 used in the present embodiment is an example, and the size and number of the catalyst support blocks 20 stored in the storage container 12 can be selected as appropriate.

The catalyst support block 20 is formed as a porous body in which a flow path such as a honeycomb structure or a three-dimensional network structure is extremely complicated, and is configured so that a contact area between the gas and the catalyst (oxide semiconductor) becomes extremely large. The substrate is loaded with an oxide semiconductor such as chromium oxide as a catalyst. A commercially available ceramic foam can be used as the base material having such a honeycomb structure or a three-dimensional network structure. This ceramic foam is used as a filter to filter smelted liquid metal, has a random three-dimensional structure, high collision frequency with the passing gas, light weight, heat capacity Is advantageous in that the transmittance is as low as 80%. The ceramic foam is provided as a plate-like product, and can be cut to a desired size or punched, and can be processed and used in accordance with a purification device.
As the oxide semiconductor supported on the base material, various oxide semiconductors can be used as described above. Among them TiO _{2, ZnO, NiO,} preferably _{Cr 2 O 3, Fe 2 O} 3, further chromium oxide is used in the most favored.

  The characteristic feature of the purification apparatus of the present embodiment is that the catalyst support block 20 is stored in the storage container 12 in such a manner that the side surfaces of the catalyst support block 20 are in contact with each other (contact), and (Heater insertion hole) 20a is provided so as to penetrate therethrough, and the heater 30 is accommodated in the heater accommodating portion 20a. In the embodiment, a cylindrical rod heater (outer diameter 10 mm, length 52 mm) is used as the heater 30, and a heater accommodating portion 20 a having an inner diameter of 12 mm is provided.

Actually, when the catalyst support block 20 is provided with concave grooves having a semicircular cross section on the surfaces that contact each other, and the catalyst support block 20 is disposed facing each other, a circular heater housing portion 20a is formed. It was to so.
As shown in FIG. 2, in the embodiment, in each of the two contact surfaces of the catalyst support block 20, two heater storage portions 20 a are provided and the storage container 12 is mounted with the catalyst support block 20. In total, 12 heater housing portions 20a are provided.

FIG. 3 shows an assembly diagram of the storage container 12.
FIG. 3A shows a state in which the catalyst carrying block 20 is housed in a case portion 12b formed in a U-shape and the case portion 12b is covered with a lid 12c. The block body in which the catalyst carrying block 20 is accommodated is provided with a heater accommodating portion 20a, and the lid 12c is provided with an opening 12d for inserting the heater in alignment with the heater accommodating portion 20a.
FIG. 3B shows a state in which the catalyst carrying block 20 is stored in the storage container 12.

FIG. 1 shows a state in which a catalyst carrying block 20 is stored in a storage container 12 and a rod heater is inserted and mounted as a heater 30 in a heater storage portion. A conductive wire 31 extends from the end of the heater 30 and is connected to a power source. Since the heater 30 is inserted into the catalyst carrying block 20 from the outside (upper surface side in the illustrated example) of the storage container 12, the heater storage portion only needs to be opened on one surface of the storage container 12.
If an opening for inserting a heater is provided in advance in the storage container 12 in accordance with the number of catalyst support blocks 20 to be stored in the storage container 12 and the arrangement position thereof, after the catalyst support blocks 20 are stored in the storage container 12, A purification treatment unit can be configured simply by inserting the heater 30.

  The method for assembling the storage container 12 and the method for assembling the storage container 12 and the ducts 14a and 14b are not limited to the above example, and can be appropriately assembled by appropriately preparing parts for assembly. . For example, as in the above example, the storage container 12 and the ducts 14a and 14b may be separate parts and the ducts 14a and 14b may be connected after the storage container 12 is assembled. Alternatively, the storage container 12 and the ducts 14a and 14b may be connected. It is also possible to prepare a divided part in which the storage container 12 and the ducts 14 and 14b are assembled together while the catalyst carrying block 20 is stored in the storage container 12.

  FIG. 4 shows a state in which the catalyst carrying block 20 is accommodated in the storage container 12 as viewed from the end surface direction of the storage container 12. Since the catalyst support block 20 is made of a mesh-like material such as ceramic foam, the catalyst support block 20 is stored between the inner surface of the storage container 12 and the outer surface of the catalyst support block 20 in a state where the catalyst support block 20 is stored in the storage container 12. It can happen that the gas to be treated leaks. For this reason, in the embodiment, a heat insulating material 35 having a gas sealing property is sandwiched between the inner side surface of the storage container 12 and the side surface of the catalyst support block 20, and the side surface of the catalyst support block 20 and the inner side surface of the storage container 12 are Between the catalyst carrying block 20 and the storage container 12 is prevented from conducting heat.

The heat insulating material 35 can ensure heat resistance that can sufficiently withstand the heating temperature (about 350 ° C. to 500 ° C.) of the catalyst supporting block 20 and sealing performance that hermetically seals the catalyst supporting block 20 and the storage container 12 at the heating temperature. If it is a raw material, a raw material can be used suitably. The thickness of the heat insulating material 35 may be set appropriately.
When the catalyst-carrying block is put in, for example, a stainless steel storage container 12 so as to be wrapped with the heat insulating material 35, the inner surface of the storage container 12 is mirror-finished, and the release of heat to the outside of the system is minimized by heat reflection.

Ensuring a sealing property between the catalyst carrying block 20 and the wall surface of the storage container 12 is a problem to be noted when performing the purification process with certainty. In the purification apparatus of the present embodiment, the gas to be treated can be reliably purified by sandwiching the heat insulating material 35 having sealing properties between the entire side surface of the catalyst carrying block 20 and the inner side surface of the storage container 12. I have to.
In addition, between the opening 12d into which the heater 30 is inserted and the outer surface of the heater 30, a heat insulating sheet is packed between the heater 30 and the opening 12d for sealing.

The purification processing unit 10 shown in FIG. 1 is a main component of the purification device, and when actually used, the outside of the purification processing unit 10 is covered with a heat insulating material, and the purification processing unit 10 is kept warm to perform the purification process. Heat is prevented from escaping from the portion 10 and the purification treatment portion 10 heated to a high temperature is not touched for safety protection. In the actual apparatus, the entire storage container 12 was covered with a heat insulating material, and the purification treatment part was stored in a metal case (decorative box). Cotton-like alumina fibers and glass fibers can be used as the heat insulating material covering the outer surface of the purification treatment unit, and industrial equipment heat insulating plates and diatomaceous earth plates can be used as the plate-like heat insulating materials.
When attaching a heat insulating material, it can attach using the flange 12a provided in the edge of the storage container 12. FIG.

  The catalyst supporting block 20 controls the temperature so that the catalytic action of the oxide semiconductor supported on the base material acts reliably by controlling energization to the heater 30. In the embodiment shown in FIGS. 2 and 3, an insertion hole 21 for inserting a temperature sensor (thermocouple) is provided at the center of the catalyst carrying block 20, and a set hole 12 e is also provided in the storage container 12. The temperature of the catalyst carrying block 20 is controlled by controlling the energization to the catalyst.

(Bending heater arrangement example)
The purification device described above is an example in which a rod-shaped heater (rod heater) is mounted as the heater 30. FIG. 5 shows an example in which the M-shaped heater 32 shown in FIG. 6 is mounted on the catalyst carrying block 22 as a bent heater. FIG. 5A shows an example in which the catalyst support block 22 in which the M-shaped heater 32 is mounted in the concave groove 22a formed in the catalyst support block 22 is combined with another catalyst support block. FIG. 5B is a planar arrangement on the mounting surface of the catalyst carrying block 22 on which the M-shaped heater 32 is mounted.

In the present embodiment, a groove 22a is provided at a depth at which the M-shaped heater 32 is just buried in the end surface (contact surface) of one of the catalyst support blocks 22 arranged so that the end surfaces are in contact with each other to serve as a heater accommodating portion. The contact surface of the other catalyst block 22 is a flat surface. Of course, a concave groove 22a having a semicircular cross-sectional shape may be provided on both contact surfaces of the catalyst support block 22 arranged opposite to each other, and the concave groove may be combined to form a heater accommodating portion.
When a bent heater such as the M-shaped heater 32 is used, a plurality of catalyst supporting blocks are used in combination, and a heater accommodating portion is formed on the abutting surface (contact surface) of the catalyst supporting block. A method of mounting a heater is effective.
When the rod-shaped heater such as the rod heater described above is used, the heater may be mounted by providing a heater accommodating portion in the catalyst supporting block itself without necessarily using the abutting surface of the catalyst supporting block.

As in this embodiment, by arranging the heater directly inside the catalyst support block itself, the catalyst support block can be efficiently heated, and the catalyst support block can decompose and purify harmful substances. Can be effectively performed. In addition, by incorporating a heater in the catalyst block itself, it is possible to achieve a compact purification apparatus as a whole.
When the heater is built in the catalyst support block, the shape of the heater to be used, the size (diameter dimension) of the heater, and the heater arrangement interval are taken into consideration in consideration of the flow rate of the gas to be processed passing through the catalyst support block. Etc.

(Production method of catalyst support block)
As a method of providing a storage portion (heater insertion hole) for storing a heater in the catalyst support block, there is a method of providing the ceramic porous body that is a base material of the catalyst support block by machining (processing by a milling machine or a router). However, the ceramic porous body is fragile, and fragments are likely to scatter during processing, which makes it difficult to process, and the cutting blade is easily damaged, and the ceramic cutting dust enters the moving parts of the machine and damages the processing equipment. There is.

As a method for solving such a problem, it is effective not to form the heater housing part after forming the ceramic porous body, but to form the heater housing part in the manufacturing process of the ceramic porous body. It is.
The ceramic porous body is produced by first molding a foam according to the shape (outer shape) of the ceramic porous body to be produced. The foam is a base material for forming a porous body, and a foam having a porous structure such as a foamed urethane structure such as a honeycomb structure or a three-dimensional network structure is used.
The foamed urethane is usually provided as a cubic foamed urethane body having a size of about 1 × 1 × 1 m. A flat plate-like foam having a desired size (for example, 300 × 300 × 30 mm) is cut out from the foamed urethane body (step of molding the foam). Although the magnitude | size and shape of a ceramic porous body can be set suitably, below, the example which forms a flat ceramic porous body is demonstrated.

  Fig.7 (a) shows the foam 40 used for a flat ceramic porous body. As a method of providing, for example, an M-shaped groove as a heater accommodating portion in this foam, a method of punching foamed urethane having a thickness of about 20 mm into an M shape and sticking it on the foam 40 can be considered. However, this method requires a Thomson blade for punching urethane foam and a punching device, which increases costs. Moreover, the method of processing a groove | channel by the method of freezing urethane foam with liquid nitrogen etc., attaching this to a milling machine, and digging a groove | channel with a rotation chisel is also possible. However, this method is not realistic considering mass productivity.

FIG. 7 (b) shows a method for processing a groove serving as a heater accommodating portion in the foam 40. The heated metal wire is swept over the foam 40 to burn out the foam 40 and form a groove (heater accommodating portion). The metal wire is used as a heating element that burns out the foam 40, and a Ni—Cr wire or a platinum wire can be used as the heater wire. The metal wire is bent into a U-shape to form a heating element 44, the heating element 44 is fixed to the electrode of the insulator 45, and the heating element 44 and the power supply 46 for energization are connected.
When the heating element 44 is energized and swept while the red-heated heating element 44 is in contact with the foam 40, the portion where the metal wire is in contact with the foam 40 is burned out, and the heating element 44 acts like a knife to generate heat. The region through which the body 44 has passed is cut out from the foam 40 (a step of forming a groove shape serving as a heater accommodating portion in the foam).

FIG. 7B shows an example in which the heating element 44 is swept in an M shape in order to provide an M-shaped heater housing (the heating element is moved as indicated by the arrow in the figure).
FIG. 7C shows a state where the groove 42 is formed in the foam 40 by performing an operation of sweeping the heating element 44. The width and depth of the groove 42 can be arbitrarily set by adjusting the width and depth (length) of the U-shaped portion of the heating element 44 formed by the metal wire. When the heating element 44 is swept, the depth of the groove 42 can be set by adjusting the depth of the heating element 44 that sinks from the surface of the foam 40.

(Experimental example 1)
An example in which an operation for forming a groove in urethane foam using a heating element will be described.
A foamed urethane plate (300 × 300 × 30 mm) having a gas permeability of about 80% was used as the foam.
As the heating element, a Ni—Cr wire having a diameter of 0.5 mm was used as a metal wire, and the metal wire was processed into a U shape having a width of 10 mm and a depth of 10 mm to obtain a heating element.
A groove could be formed on the foam by sweeping the heat generator in an M shape on the foam with an applied voltage of the heat generator of 1 V and a sweep rate of 5 cm / sec. The groove formed on the foam had a width of 10 mm and a depth of 10 mm.

(Experimental example 2)
The same heating element as that used in Experimental Example 1 was used, and an experiment was conducted in which an M-shaped groove was formed on a foamed urethane plate (300 × 300 × 50 mm) having a gas permeability of about 40%. The applied voltage and sweep speed of the heating element are the same as in Experimental Example 1.
Also in this experiment, the M-shaped groove is formed according to the sweep path of the heating element by sweeping the heating element in the M shape on the foam, and the width of 10 mm and the depth of 10 mm on the foam. It was confirmed that the grooves were formed.
These experimental results show that the method of using a metal wire as a heating element and heating the metal wire to burn out the foam can be effectively used as a method for forming a groove on the foam.

The method of forming a groove in a foam using a heating element using a metal wire is that the processing apparatus can be completed with a very simple configuration, and that the groove processing operation is simple and can be formed in a short time. There is an advantage that the groove can be formed in an arbitrary shape of a straight line or a curve only by controlling the sweeping direction (how to move) the heating element.
Further, the method of forming the groove by sweeping the heating element also has an advantage that it is not restricted by the shape and size of the foam that is the object for forming the groove. The operation of sweeping the heating element to form the heater accommodating portion is an operation with a very high degree of freedom, and is not limited to the case where the accommodating portion is formed in a flat foam such as a flat plate, but a columnar or cylindrical shape. It is also possible to easily form the accommodating portion for a foam having a curved outer surface such as a body shape.

  As a method of forming the housing part by sweeping the heating element, it can be formed by manually moving the heating element using a guide, or by sweeping the heating element by an operation means such as a robot for operation. It is also possible to form grooves. If it is the method of forming an accommodating part (groove) using an operation means, a groove can be accurately formed in a foam and the process which forms an accommodating part can also be automated. The processing apparatus for forming the heater accommodating portion in the foam includes a support portion for supporting the foam as the object to be processed, an operating means for moving the heating element while the heating element is energized, and an operating means. Thus, it is only necessary to provide a control unit that controls a path for sweeping the heating element on the foam.

  The groove 12 provided in the foam 10 shown in FIG. 7C is provided with a size that allows the heater 6 to be buried in the groove 12 and accommodated therein. Depending on the catalyst unit, a plurality of ceramic porous bodies may be used in combination. When two ceramic porous bodies face each other and a heater is disposed between the opposing surfaces (contact surfaces) of the ceramic porous body, each of the opposing surfaces of the set of foams has a 1 / outer diameter of the heater. A groove having a depth of 2 may be formed and used in combination.

After the grooves 42 are formed in the foam 40 by the above-described method, the foam 40 is impregnated in a slurry in which a ceramic component such as alumina, magnesia, silica, and the like and a binder component are mixed, and the foam 40 is filled inside. Soak the slurry until
Next, after removing the excess slurry, the foam to which the slurry is attached is dried and then fired at about 1600 ° C. In the firing step, the polyurethane of the foam is decomposed and removed, and alumina, magnesia, and silica, which are ceramic components of the slurry, become a solid solution, and a porous body having a honeycomb structure or a three-dimensional network structure is obtained (process for forming a porous body) ).
In the process of drying and firing the foam impregnated with the slurry, when the dimensions of the foam and the fired body (ceramic porous body) change, the difference in dimensions between the foam and the fired body is assumed in advance. What is necessary is just to set the width | variety and depth of the groove | channel formed in a foam. Since the dimensional accuracy of the housing portion of the heater of the catalyst block is not so high, the width and depth of the housing portion (groove) formed in the foam may be set in consideration of manufacturing errors and the like.

The catalyst supporting block is obtained by supporting an oxide semiconductor such as chromium oxide on the ceramic porous body produced by the above-described method (step of supporting the oxide semiconductor on the porous body).
The operation for supporting the oxide semiconductor may be carried out by preparing a dispersion in which the oxide semiconductor is dispersed, immersing the ceramic porous body in the dispersion, attaching the dispersion to the ceramic porous body, and then drying. .
Since the groove is formed in the ceramic porous body in advance, the shape of the groove is also maintained in the catalyst block after supporting the oxide semiconductor, and a catalyst supporting block having a heater accommodating portion is obtained.

  FIG. 8 shows a catalyst unit 8 in which an M-shaped heater 6 is mounted on a catalyst support block 5 supporting an oxide semiconductor. The heater 6 used in the catalyst unit 8 is a sheath type heater (outer diameter: 10 mm) having an M-shaped planar shape. An upper surface of the catalyst block 5 is provided with an M-shaped accommodating portion (groove) for accommodating the heater 6, and the heater 6 is set in the accommodating portion by setting the heater 6 according to the accommodating portion. Contained as if buried.

Hereinafter, an example will be described in which a gas purification device is assembled using a catalyst support block provided with a heater accommodating portion and VOC is actually processed.
Example 1
As a small purification device, a purification device that consists of four catalyst support blocks with a size of 73 x 50 x 30 mm arranged in a row and stored in the storage container 12 is used. Was measured in ppmC).
The base material of the catalyst supporting block is ceramic foam, and the supported catalyst is chromium oxide. The periphery of the storage container 12 was arranged to be surrounded by a diatomaceous earth block of heat insulating material. The heaters used were four rod heaters with a diameter of 10mm, a length of 51mm, and 300W. The heater 30 was the same as the arrangement shown in FIG. The heating temperature of the catalyst support block by the heater 30 is 400 ° C.
Air was the carrier gas, and VOC was treated with THF (tetrahydrofuran). The air volume is about 0.3m ³ / min. Table 1 shows the measurement results.

(Example 2)
As a medium-sized purification device, a purification device in which four catalyst support blocks each having a size of 100 x 100 x 30 mm are arranged, and a catalyst support block having a size of 100 x 100 x 120 mm as a whole is housed in the storage container 12 is configured. Then, the decomposition characteristics of VOC were measured. The base material of the catalyst supporting block is ceramic foam, and the supported catalyst is chromium oxide.
The periphery of the storage container 12 was insulated by being surrounded by a ceramic block of heat insulating material. The outer surface temperature of the heat insulating material is about 50 ° C.
The heater used was a rod heater with a diameter of 10mm, 120mm and 300W. As in FIG. 2, four heaters were arranged. The heating temperature of the catalyst support block is 400 ° C.
The decomposition characteristics were measured using air as the carrier gas and THF as the gas to be treated. The air volume is about 0.3m ³ / min. Table 2 shows the measurement results.

(Example 3)
As the smallest purification device, a catalyst carrying block having a size of 20 × 50 × 73 mm was accommodated in the storage container 12 to constitute a purification treatment unit, and the VOC purification characteristics were measured. In this case, the VOC gas enters from the opening of 20 × 50 mm and travels a distance of 73 mm in length.
The purification apparatus of the present embodiment is an example assembled using only one catalyst support block.
The long side (73mm) of the catalyst support block is placed in parallel with the direction of the gas to be processed (the direction in which the gas to be processed passes), and two rod heaters are placed along the long side of the catalyst support block. did. The rod heater is 6.25mm in diameter, 51mm in length, and 250W. The heating temperature of the catalyst support block is 400 ° C.
The decomposition characteristics were measured using air as the carrier gas and toluene as the gas to be treated. The air volume is about 0.2m ³ / min. Table 3 shows the measurement results.

  All of the purifying devices shown in the above-described embodiments are configured so that the heater is inserted so that the heater is inserted into the catalyst supporting block, so that the container (processing space) for storing the catalyst supporting block is made the size of the catalyst supporting block. It is possible to reduce the size of the apparatus most efficiently in a form that can be of the same level and that can maximize the function of the catalyst support block. Therefore, the most efficient and compact purifying apparatus can be configured by selecting the catalyst carrying block having the most efficient size according to the processing amount of the gas to be processed and configuring the purifying apparatus.

  The catalyst carrying block used in the purification device is not limited in size or shape. In the purification apparatus of the embodiment, a square columnar catalyst support block is used, but a cylindrical catalyst support block may be used. A plurality of catalyst supporting blocks can be used in combination, or as in Example 3, it can be constituted by only one catalyst supporting block.

  A heater can be appropriately used as the heater mounted on the catalyst carrying block. The heater accommodating portion is usually provided in a direction in which the longitudinal direction of the accommodating portion (insertion hole) is orthogonal to the direction in which the gas to be processed is conveyed. With this arrangement, the gas to be treated can be efficiently purified by uniformly heating the entire catalyst support block without disturbing the flow of the gas to be treated. In addition, it is also possible to provide the heater accommodating portion on the catalyst support block in parallel with the direction in which the gas to be processed is conveyed because of the arrangement of the purification device and the like. In this case, the conductive wire connected to the heater may be drawn to the exhaust duct side, for example.

  The purification apparatus shown in Example 3 is formed in a size of about 100 mm square including a heat insulating material that protects the purification treatment unit. It is possible to further reduce the size of the purification device by, for example, a method in which the catalyst support block is formed to be elongated. By downsizing the purification device, it can be widely used for applications such as attaching a purification device to equipment or devices that generate harmful organic compounds so that harmful substances are not discharged to the outside. In addition, as a device configuration when the amount of VOC processing is large, the unit of the present application (for example, a unit in which 100 mm square catalyst blocks are connected in series in four stages) can be connected in parallel to cope with a large air volume. is there. Furthermore, since the VOC gas introduced into the furnace is preheated by installing a heat exchanger, the air volume can be dramatically increased. The purifying apparatus according to the present invention has an extremely powerful action of decomposing and purifying harmful substances such as organic compounds, and the use of this purifying action can greatly contribute to environmental improvement.

  Note that the purification apparatus shown in FIG. 1 or the like has an air supply mechanism that feeds the gas to be processed into the purification processing unit, an exhaust mechanism that exhausts the purified gas from the purification processing unit, and heat exchange that effectively uses exhaust heat. No vessel is attached. The air supply mechanism or the exhaust mechanism may be provided separately from the purification device, and the air supply mechanism or the exhaust mechanism may be connected to the purification device for use. Alternatively, the air supply fan or the intake fan may be connected to the purification device in advance. It can also be set as the attached structure. Necessary air supply and exhaust functions can be achieved by placing a small fan in the duct.

DESCRIPTION OF SYMBOLS 10 Purification processing part 12 Storage container 12a Flange 12b Case part 12c Cover 12d Opening 12e Set hole 14a, 14b Duct 20 Catalyst carrying block 20a Heater accommodating part 21 Thermocouple insertion hole 22 Catalyst carrying block 22a Concave groove 30 Heater 32 M-shaped heater 35 Heat Insulating Material 40 Foam 42 Groove 44 Heating Element

Claims (2)

A method for producing a catalyst-carrying block, comprising:
The catalyst carrying block is provided with an accommodating portion formed in a groove shape that matches the planar shape of the heater to be accommodated,
The catalyst supported on the block is an oxide semiconductor, and when heated to a temperature region where a large amount of holes and electrons are generated by interband transition of the oxide semiconductor, the organic semiconductor in contact with the oxide semiconductor The compound is oxidatively decomposed by the oxidizing power of the holes in the presence of oxygen,
As a manufacturing process, a process of forming a foam according to the outer shape of the catalyst-carrying block;
On the molded foam, the heating element made of a metal wire bent to match the cross-sectional shape of the heater accommodated in the catalyst support block is swept while being heated, and the foam in the region through which the heating element has passed is removed. A step of forming a groove shape serving as a housing portion of the heater in the foam,
After the ceramic slurry is immersed in the foam having the groove shape, the foam is dried and fired to decompose and remove the foam to form a porous body made of the ceramic component of the slurry. And a process of
Carrying the oxide semiconductor in the porous body;
A process for producing a catalyst-carrying block, comprising: A catalyst supporting block manufactured by the manufacturing method according to claim 1, a storage container for storing the catalyst supporting block, and a heater for heating the catalyst supporting block. A gas purifying device accommodated , wherein a plurality of catalyst supporting blocks including the catalyst supporting block are arranged in contact with each other in series in the storage container, and at least of contact surfaces of the catalyst supporting blocks facing each other. A gas purification apparatus, wherein a concave groove is formed on one side to form a housing portion for the heater.