JP2015182950A - Honeycomb structure, and gas treatment device including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a honeycomb structure which less likely causes an inspection mistake when whether there is a gap between a sealing material and a partition wall is inspected by using white light, from which an identifier such as a bar code is formed easily and which has high identification force as the identifier, and to provide a gas treatment device including the honeycomb structure.SOLUTION: The honeycomb structure 1 includes: a cylindrical part 2; a plurality of partition wall parts 3 arranged on the inside of the cylindrical part 2; and the sealing material 4. The spaces surrounded by the cylindrical part 2 and the partition wall part 3 or the adjacent partition wall parts 3 are used as flow passages 5 of a fluid. An inflow port or an outflow port of the flow passage 5 is sealed by the sealing material 4. Each of the cylindrical part 2, the partition wall part 3 and the sealing material 4 comprises an aluminum titanate sintered compact. The Hunter whiteness degree on the exposed surface thereof is 32-40.

Description

  The present invention relates to a honeycomb structure used for a filter or the like for purifying exhaust gas, and a gas processing apparatus including the honeycomb structure.

  Conventionally, a filter having a honeycomb structure (hereinafter simply referred to as a honeycomb structure) has been used to collect fine particles contained in exhaust gas generated from an internal combustion engine, an incinerator, a boiler, and the like. The honeycomb structure includes a cylindrical portion, a plurality of partition walls provided inside the cylindrical portion, and a sealing material, and a space surrounded by the cylindrical portions and the partition walls or the partition walls is formed. A fluid flow passage is formed, and the inlet or outlet of the flow passage is sealed with the sealing material. As a material for such a honeycomb structure, silicon carbide or cordierite is known. However, since silicon carbide has low thermal shock resistance and requires a segmentation to form a honeycomb structure, and a bonding layer for joining the segmented honeycomb structure is required, the pressure loss increases. There was a problem. Cordierite has advantages such as low thermal expansion and low cost, but has problems such as being easily reacted with ash components in the exhaust at high temperatures and low heat resistance.

  On the other hand, aluminum titanate having a melting point as high as 1500 ° C. or more and excellent fire resistance and having a large heat capacity and a low temperature during regeneration has been proposed (see Non-Patent Document 1).

Nemoto et al. “Development of Aluminum Titanate Diesel Particulate Filters—Product Design and Characteristic Evaluation”, Sumitomo Chemical Co., Ltd., 2011, p4-13

  FIG. 4 indicates that the honeycomb structure made of aluminum titanate has a white color tone. In this way, when the honeycomb structure has a white color tone, light is irradiated from the open end face, for example, the inlet side, and the gap between the sealing material on the outlet side and the partition wall When inspecting for the presence or absence, white light is mainly used for irradiation, but even if there is a gap between the sealing material and the partition, it passes through the partition and the sealing material. Since the contrast with white light is weak, there is a problem that inspection mistakes are likely to occur.

  Note that when an identifier such as a barcode is printed in a dark color such as black on the outer surface of the tubular portion of the honeycomb structure, the barcode having a high discriminating power is composed of white and black which are color tones of both poles. However, in order to increase the contrast with white light, it has not been sufficient to simply make the honeycomb structure exhibit a black color tone.

  Therefore, the present invention can make it difficult to cause an inspection error in the inspection of the presence or absence of a gap between the sealing material and the partition wall by white light, and it is easy to form an identifier such as a barcode. It is an object of the present invention to provide a honeycomb structure having a high discriminating power and a gas processing apparatus including the honeycomb structure.

  The honeycomb structure of the present invention includes a tubular part, a plurality of partition walls provided inside the tubular part, and a sealing material, and the tubular part and the partition part or between the partition parts The space surrounded by the flow path serves as a fluid flow path, and the inlet or outlet of the flow path is sealed with the sealing material, and the cylindrical portion, the partition wall portion, and the sealing material are sintered with an aluminum titanate-based material. The hunter whiteness on the exposed surface is 32 or more and 40 or less.

  The gas treatment device of the present invention is characterized in that the honeycomb structure having the above-described structure is provided in a case to which an exhaust pipe is connected.

  According to the honeycomb structure of the present invention, it is possible to make it difficult to cause an inspection error in the inspection of the presence or absence of a gap between the sealing material and the partition wall by white light, and it is easy to form an identifier such as a barcode. The discriminating power of the identifier is high.

  In addition, according to the gas treatment device of the present invention, since the honeycomb structure having the above-described structure is provided, the honeycomb structure has few gaps, so that high collection of particulates and the like contained in the exhaust gas is high. Has high efficiency and high reliability. Moreover, since the discriminating power of the identifier is high, the honeycomb structure can be easily managed.

An example of the honeycomb structure of the present embodiment is shown. (A) is a perspective view, and (b) is a cross-sectional view taken along line B-B ′ in (a). It is a schematic sectional drawing of the gas treatment apparatus which shows an example of this embodiment typically.

  Hereinafter, an example of an embodiment of a honeycomb structure of the present invention and a gas processing apparatus including the honeycomb structure will be described.

  FIG. 1 shows an example of the honeycomb structure of the present embodiment, in which (a) is a perspective view and (b) is a cross-sectional view taken along line B-B ′ in (a).

  The honeycomb structure 1 of the example shown in FIG. 1 includes a tubular portion 2, a plurality of partition walls 3 provided inside the tubular portion 2, and a sealing material 4. 3 or a space surrounded by the partition walls 3 is a fluid flow path 5, and an inlet or an outlet of the flow path 5 is sealed with a sealing material 4. In FIG.1 (b), the left side is an inflow port and the right side is an outflow port. The honeycomb structure 1 has a cylindrical shape in which the flow passage 5 extends in the axial direction A.

  Here, as the flow of the exhaust gas (EG), the exhaust gas that has entered the flow passage 5a having an inflow port opened and an outflow port sealed by the sealing material 4 flows as shown by an arrow. When it goes to the exit side, it flows out from the flow path 5b through the partition part 3. The fine particles contained in the exhaust gas are mainly collected by the partition wall 3 in such a flow.

For example, the partition wall 3 has a porosity of 35 volume% or more and 65 volume% or less, and a pore diameter (p ₅₀ ) of 50 volume% in the cumulative distribution curve of pore diameter is 5 μm or more and 26 μm or less. The stopper 4 has a porosity of 50% to 65%, and a pore diameter (p ₅₀ ) of 12 μm to 18 μm. In addition, the average pore diameter and porosity of the partition part 3 and the sealing material 4 are the values calculated | required based on the mercury intrusion method.

Further, in the honeycomb structure 1 of the present embodiment, the tubular portion 2, the partition wall portion 3 and the sealing material 4 are made of an aluminum titanate sintered body. Here, the aluminum titanate sintered body is a sintered body containing more than 50 mass% of aluminum titanate out of 100 mass% of all components constituting the aluminum titanate sintered body. In addition, what is necessary is just to identify the component (crystal structure) which comprises an aluminum titanate sintered compact, using a X-ray-diffraction apparatus (XRD), collating with a JCPDS card | curd. In addition, the content is obtained by using an ICP (Inductively Coupled Plasma) emission spectroscopic analyzer (ICP) or a fluorescent X-ray analyzer (XRF) to obtain the Al content and converted to Al ₂ TiO ₅ (aluminum titanate). do it.

  And the honeycomb structure 1 of this embodiment has a hunter whiteness of 32 to 40 on the exposed surface. In addition, an exposed surface is a surface which can be visually recognized, such as the end surface of an inflow port and an outflow port, the outer surface of the cylindrical part 2. FIG. And by satisfy | filling such a structure, when inspecting the presence or absence of the clearance gap between the partition part 3 and the sealing material 4 by irradiating white light from an inflow port side, the color tone of the end surface of an outflow port and Since the contrast with the white light passing through the gap becomes strong, an inspection error for the presence or absence of the gap is less likely to occur.

  Further, when an identifier such as a barcode is printed in a dark color such as black on the outer surface of the tubular portion 2 that is the exposed surface of the honeycomb structure 1, for example, a predetermined interval is formed on the outer surface of the tubular portion 2 By performing black printing with, it is possible to form a barcode using the color tone on the outer surface, so that the barcode can be easily formed. Furthermore, the identifier formed in this way has high discrimination power due to the color tone difference between the color tone on the outer surface and the black color. In particular, the Hunter whiteness on the exposed surface is preferably 34 or more and 38 or less.

  Further, when the collected fine particles are burned and removed with a heater, the honeycomb structure 1 of the present embodiment has a higher radiant heat absorption efficiency than the honeycomb structure exhibiting a white color tone. The combustion removal efficiency is improved.

Here, Hunter whiteness is a calculated value defined by the following formula (1), L * is a lightness index in the CIE1976 L * a * b * color space of the exposed surface, and a * and b *. Are both chromaticness indices in the same space. The lightness index L * and the chromaticness index a *, b * can all be determined according to JIS Z 8722-2009. Note that 0 is completely black and 100 is completely white.
Hunter whiteness = 100−√ [(100−L *) ² + (a * ² + b * ² )] (1)

Further, the exposed surface of the honeycomb structure 1 of the present embodiment has a spectral reflectance curve of 460 nm.
It is preferable that the spectral reflectance has a minimum value in the wavelength range of 480 nm or less. When the above-described configuration is satisfied, a part of the blue light can be absorbed, so that the burden on the operator's eyes caused by the inspection for the presence or absence of a gap can be reduced. In recent years, white light is realized by a combination of a blue LED and a yellow LED in many cases, which is particularly suitable for inspection using white light of an LED. In addition, a spectral reflectance curve can be created from the spectral reflectance calculated | required based on JISZ8722-2009, and what is necessary is just to confirm the created spectral reflectance curve for the minimum value of a spectral reflectance.

  Moreover, in the honeycomb structure 1 of the present embodiment, it is preferable that the spectral reflectance in the wavelength range of 360 nm to 740 nm on the exposed surface is 5% to 25%. When such a configuration is satisfied, when the collected and deposited fine particles are burned, the unburned fine particles can be easily confirmed, and the adhesion and solidification of the metal powder that causes melting damage can be easily performed. Can be confirmed. In addition, what is necessary is just to obtain | require the spectral reflectance of the wavelength range of 360 nm or more and 740 nm or less based on JISZ8722-2009.

The honeycomb structure 1 of the present embodiment has, for example, a columnar shape having an outer diameter D of 140 to 270 mm, a length L in the axial direction A of 100 to 250 mm, and a cylindricity of 2.5 mm or less. The number of the flow passages 5 in the cross section perpendicular to the direction A is 5 to 124 per 100 mm ² (32 to 800 CPS).
I). Moreover, the thickness of the partition part 3 is 0.05 mm or more and 0.25 mm or less, and the thickness of the sealing material 4 is 1 mm or more and 5 mm or less. CPSI stands for Cells Per Square Inches.

Moreover, the effective filtration area of the honeycomb structure 1 is preferably 1.1 m ² / L or more, and more preferably 1.4 m ² / L or more. The upper limit of the effective filtration area is, for example, 2.0 m ² / L from the viewpoint of reducing both pressure loss caused by repeated collection and thermal stress caused by burning fine particles. The effective filtration area in the honeycomb structure 1 refers to the total surface area of the partition walls 3 (excluding the portion in contact with the sealing material 4) in contact with the fluid per 1 L (liter) of the honeycomb structure.

  FIG. 2 is a schematic cross-sectional view of a gas processing apparatus schematically showing an example of this embodiment.

  In the gas processing apparatus 20 of the example shown in FIG. 2, the honeycomb structure 1 of the present embodiment is accommodated in a case 8 made of stainless steel or the like with the outer periphery held by the gripping material 7. In addition, an introduction pipe 9 communicating with an internal combustion engine (not shown) such as a diesel engine or a gasoline engine is connected, and a discharge pipe (not shown) is connected to the outflow port 8b. Here, the gripping material 7 is preferably a heat insulating material. In this case, the heat generated in the honeycomb structure 1 is transferred to the case 8 due to the combustion removal of the fine particles, and the case 8 is deformed or deteriorated. Can be suppressed.

The gripping material 7 is preferably made of at least one of ceramic fiber, glass fiber, carbon fiber, and ceramic whisker, for example. The case 8 is made of, for example, stainless steel such as SUS303, SUS304, and SUS316.
The central part is formed in a cylindrical shape, and both end parts are formed in a truncated cone shape.

  When the internal combustion engine is operated and EG is supplied to the case 8 through the introduction pipe 9, the EG is introduced into the flow passage 5 a of the honeycomb structure 1. Since the front of the flow passage 5a is blocked by the sealing material 4a, the EG traveling through the flow passage 5a passes through the partition wall 3 and is introduced into the adjacent flow passage 5b. As described above, when the EG passes through the partition wall portion 3, the fine particles in the EG are collected on the surface of the open pores opened on the inflow side surface of the partition wall portion 3 and the inner surface of the continuous air holes. The EG in which the fine particles are collected is discharged from the flow passage 5b in a purified state, and is discharged to the outside through the outlet 8b.

  In the present embodiment, an example using exhaust gas in which the fluid is a gas has been described. However, a liquid may be used as the fluid. For example, clean water or sewage can be used as the fluid, and the gas treatment device 20 of the present embodiment can also be applied for liquid filtration.

  Next, an example of a method for manufacturing the honeycomb structure 1 will be described.

First, 27 to 33% by mass of aluminum oxide powder, 13 to 17% by mass of ferric oxide powder, 7 to 13% by mass of magnesium oxide powder, 0.1 to 2% by mass of silicon oxide powder, and the balance The mixed raw material prepared as titanium oxide powder is dry mixed to obtain a primary raw material. Here, it is more preferable that each powder to be used has a purity of 99.0% by mass or more, particularly 99.5% by mass or more. In addition to the oxide powders described above, powders such as carbonates, hydroxides and nitrates may be used, and powders of these compounds may be used.

Next, the obtained primary raw material is calcined in an air atmosphere at a temperature of 1425 ° C. or more and 1525 ° C. or less for 2 hours or more and 6 hours or less to obtain a calcined powder composed of pseudo-brookite crystals. it can.

For example, if the calcined powder is passed through a mesh sieve having a particle size number of 230 described in ASTM E 11-61, a calcined powder having a particle size of 61 μm or less can be obtained. In addition, in the spectral reflectance curve, in order to obtain an exposed surface having a minimum spectral reflectance in the wavelength range of 460 nm to 480 nm, a calcined powder having a high reflectivity for blue light and a particle size of 0.1 μm or less is used. Remove it.

Further, a silicon oxide powder having an average particle diameter of 1 μm or more and 3 μm or less is weighed in a range of 1 part by mass or more and 2.8 parts by mass or less with respect to 100 parts by mass of the calcined powder. Further, a pore-forming agent such as graphite, starch or polyethylene resin is weighed in a range of 1 part by mass to 13 parts by mass with respect to 100 parts by mass of the calcined powder. Then, after adding calcined powder, silicon oxide powder, pore-forming agent, plasticizer, slipping agent and water and stirring using a universal stirrer, rotary mill or V-type stirrer, etc. A plasticized clay is obtained by kneading using a roll mill or a kneader.

  Next, it shape | molds using the extrusion molding machine provided with the screw which extrudes this clay. This extrusion molding machine is equipped with a molding die. As the molding die, for example, the inner diameter that determines the outer diameter of the molded body is 155 mm or more and 300 mm or less, and the partition wall portion 3 and the cylindrical portion of the honeycomb structure 1 are used. 2 to form a slit.

  Then, the clay is put into an extrusion molding machine equipped with a molding die as described above, extruded by applying pressure, and the extruded molded body is cut into a predetermined length (for example, 170 mm or more and 180 mm or less). And after spray-applying grease to the outer surface of the portion corresponding to the cylindrical portion of the obtained molded body, the molded body is placed so that the axial direction A is perpendicular to the placement surface, and placed in the microwave dryer. To obtain a dried product.

  Next, the sealing material 4 which seals each of the inflow port side and the outflow port side of the several flow path 5 of a dry body alternately is produced. Specifically, first, a portion where the sealing material 4 is not formed is masked on the end face on the outlet side. Then, a belt-like body having a longer overall length than the outer periphery of the dried body is wound around the outer periphery on the outlet side of the dried body, and the belt-like body is fixed to the dried body with an adhesive tape, a fusion tape, an adhesive tape or the like. And the end surface by the side of the outflow port of a dry body is immersed in the slurry for sealing materials stored in the cylindrical container, and it is made to dry after that.

In addition, this slurry for sealing materials is calcined powder, for example, an average particle diameter is 1 micrometer or more and 3 micrometers or less, and addition amount is 1 to 3.8 mass parts with respect to 100 mass parts of calcined powder. After adding a certain silicon oxide powder and a pore-forming agent such as graphite, starch or polyethylene resin whose addition amount is 1 to 13 parts by mass with respect to 100 parts by mass of the calcined powder, a dispersant and water Is added and mixed. Here, the viscosity of the slurry may be adjusted by appropriately adjusting the amount of the dispersant with respect to the amount of water. The band-shaped body is made of, for example, a foamed polyethylene sheet, kraft paper whose surface is coated with a propylene resin, and the thickness is preferably 1 mm or more and 3 mm or less.

  Next, baking is performed at a maximum temperature of 1320 ° C. to 1450 ° C. and a holding time of 2 to 10 hours. Note that the honeycomb structure 1 of the present embodiment in which the hunter whiteness on the exposed surface is 32 or more and 40 or less can be obtained by setting the oxygen concentration during firing to 19.5% by volume or more and 20.5% by volume or less. The hunter whiteness is less than 32 when the atmosphere during firing is an air atmosphere.

  The honeycomb structure 1 obtained by the manufacturing method described above is a solution in which magnesium titanate excellent in corrosion resistance and iron titanate excellent in heat deterioration resistance are dissolved in aluminum titanate excellent in heat resistance. Therefore, it is excellent in heat resistance, corrosion resistance and heat deterioration resistance. Note that magnesium titanate and iron titanate may be identified by measuring using XRD and collating with a JCPDS card.

  In addition, the honeycomb structure 1 obtained by the manufacturing method described above has high mechanical strength because crystals such as aluminum titanate are firmly bonded with silicon oxide.

  Further, in order to obtain the honeycomb structure 1 having a spectral reflectance in the wavelength range of 360 nm or more and 740 nm or less on the exposed surface of 5% or more and 25% or less, a closed-type firing furnace is used, and the dry body is solid. What is necessary is just to adjust the volume of the molded object arrange | positioned in a baking furnace so that the volume ratio at the time of considering may be 1% or more and 10% or less with respect to the volume of a baking furnace.

  And after accommodating in the case 8 in the state which coat | covered the outer periphery of the honeycomb structure 1 produced by the method mentioned above with the holding material 7, the introduction pipe | tube of EG is set to the inflow port 8a of the case 8, and an exhaust pipe is used. By connecting to the outlet 8b of the case 8 respectively, the gas processing apparatus 20 of the present embodiment of the example shown in FIG. 2 can be obtained.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

First, 30% by mass of aluminum oxide powder, 15% by mass of ferric oxide powder, 10% by mass of magnesium oxide powder, 0.7% by mass of silicon oxide powder and the remainder as titanium oxide powder Were dry mixed to obtain a primary material. Here, as each powder, a powder having a purity of 99.5% by mass was used.

  Next, the obtained primary raw material was calcined for 4 hours at a temperature of 1475 ° C. in an air atmosphere to obtain a calcined powder composed of pseudo-brookite crystals.

This calcined powder was passed through a mesh sieve having a particle size number of 230 described in ASTM E 11-61 to obtain a calcined powder classified to a particle size of 61 μm or less. Next, 3 parts by mass of silicon oxide powder having an average particle diameter of 2 μm was weighed with respect to 100 parts by mass of the calcined powder. Further, 7 parts by mass of starch was weighed with respect to 100 parts by mass of the calcined powder. Then, the calcined powder, the silicon oxide powder, the starch, the plasticizer, the slipping agent, and water are added, stirred using a universal stirrer, and then kneaded using a kneader. I got the dredged clay.

The starch has a spherical shape, and the ratio (d ₈₀ ) of the cumulative 80 volume% particle diameter (d ₈₀ ) to the cumulative 20 volume% particle diameter (d ₂₀ ) in the cumulative distribution curve of starch particle diameter (d ₈₀ ). / D ₂₀ ) of 1.3 was used.

Next, it shape | molded using the extrusion molding machine provided with the screw which extrudes this clay. This extrusion molding machine is equipped with a molding die, and the molding die has an inner diameter that determines the outer diameter of the molded body is 170 mm, and slits for forming the partition wall portion and the tubular portion of the honeycomb structure The thing which has was used. And the molded body extruded by applying pressure is 175 m
By cutting at a length of m, a formed body to be a honeycomb structure was obtained. And after spray-applying grease to the outer surface of the portion corresponding to the cylindrical portion of the obtained molded body, the molded body is placed so that the axial direction A is perpendicular to the placement surface, and placed in the microwave dryer. And dried to obtain a dried product.

  Next, in order to form a sealing material that seals the outlet side of the plurality of flow passages of the dry body, first, a belt-like body having a longer overall length than the outer periphery of the dry body is formed on the outer periphery of the dry body on the outlet side The belt-like body was fixed to the dry body by winding and an adhesive tape. Thereafter, the end face on the outlet side of the dried body was immersed in the slurry for sealing material stored in the cylindrical container.

  In addition, in this example, in order to dare to provide a gap between the sealing material on the end face on the outlet side and the partition wall, a resin sheet that is burned off by baking is attached to a part of the partition wall on the outlet side. I left it.

Here, the slurry for sealing material is a calcined powder, a silicon oxide powder having an average particle diameter of 2 μm, and an addition amount of 0.8 parts by mass with respect to 100 parts by mass of the calcined powder. 7 parts by weight of starch, 100 parts by weight of the sintered powder, a dispersant, and water are mixed, and the viscosity of the slurry for sealing material is adjusted to 1.8 Pa · s. It was. Further, the belt-like body was formed from a foamed polyethylene sheet and used with a thickness of 2 mm.

And after drying the slurry for sealing materials, it put into the electric furnace and baked. The maximum temperature was 1410 ° C. and the holding time was 3 hours. The oxygen concentration in the atmosphere was as shown in Table 1. The obtained honeycomb structure has a length L in the axial direction A shown in FIG.
The number of flow passages per unit area in the cross section perpendicular to the radial direction (radial direction) was 300 CPSI. Further, the porosity of the partition wall was determined by mercury porosimetry and found to be 50% by volume.

  Then, the lightness index L * and the chromaticness index a *, b * of the outer surface of the cylindrical portion, which is the exposed surface of each sample, are obtained in accordance with JIS Z 8722-2009, and the values are substituted into formula (1). Then, Hunter whiteness was calculated, and the calculated values are shown in Table 1.

  Also, count the gap between the sealing material that irradiates white light from the inlet side of each sample and seals the outlet side and the partition wall part, and sticks it to the partition part on the outlet side when forming the sealing material. Samples that were the same as the number of attached resin sheets are described as “A” in Table 1, and “B” is used for samples that have fewer gaps than the number of resin sheets and can be determined to be missed in the inspection. Described.

  Furthermore, the barcode was formed by carrying out black printing on the outer surface of the cylindrical part which is an exposed surface at a predetermined interval. Then, it was confirmed whether or not automatic recognition could be performed using an optical reader. Samples that could be automatically recognized were described as “A” in Table 1, and samples that could not be automatically recognized were described as “B” in Table 1.

  As shown in Table 1, sample no. 2 to 6, since the Hunter whiteness on the exposed surface is 32 or more and 40 or less, it is possible to make it less likely to cause an inspection error in the inspection of the presence or absence of a gap between the sealing material and the partition wall portion by white light. It was found that identifiers such as barcodes can be easily formed, and the identifiers are highly discriminating.

  Example except that a sealing material for sealing the inlet side and the outlet side was formed, a closed firing furnace was used, and the volume ratio to the volume of the firing furnace was set to the values shown in Table 2. Sample No. 1 In the same manner as in No. 5, sample no. 8-14 were produced.

  Then, the spectral reflectance in the wavelength range of 360 nm or more and 740 nm or less of the outer surface of the cylindrical portion which is the exposed surface of each sample is obtained every 10 nm according to JIS Z 8722-2009, and the maximum value of the spectral reflectance is obtained. Are shown in Table 2.

Next, each sample was held by a case and attached to the gas processing apparatus shown in FIG. And after connecting this gas processing apparatus to a carbon generator (Nippon Kanomax Co., Ltd., model S4102), the flow rate of dry air containing fine particles from this apparatus at a temperature of 25 ° C. per unit time is 2.27 Nm ³ / The collected fine particles were burned at a burning temperature of 1200 ° C. and a burning time of 8 minutes. Then, the exposed surface is visually confirmed to confirm whether or not the unburned fine particles can be recognized. The recognized sample is described as “A” in Table 2, and the unrecognized sample is listed in Table 2. B ".

In addition, by injecting metal particles having an average particle diameter (D ₅₀ ) of 50 μm to the outer peripheral surface of the cylindrical portion of each sample, it is possible to confirm and recognize whether or not metal powder is adhered and recognized. The sample was described as “A” in Table 2, and the sample that could not be recognized was described as “B” in Table 2.

  As shown in Table 2, sample no. Nos. 9 to 13 have a spectral reflectance of 5% or more and 25% or less in the wavelength range of 360 nm to 740 nm on the exposed surface. Powder adhesion and solidification can be confirmed.

1: Honeycomb structure 2: Cylindrical part 3: Partition part 4: Sealing material 5: Flow path 7: Holding material 8: Case 9: Introducing pipe
20: Gas processing equipment

Claims (4)

  A cylindrical portion, a plurality of partition walls provided inside the cylindrical portion, and a sealing material, wherein the cylindrical portion and the partition wall, or a space surrounded by the partition walls is a fluid An inflow port or an outflow port of the flow passage is sealed with the sealing material, and the cylindrical portion, the partition wall portion, and the sealing material are made of an aluminum titanate sintered body, A honeycomb structure having a Hunter whiteness of 32 to 40.   The honeycomb structure according to claim 1, wherein the exposed surface has a minimum value of spectral reflectance in a wavelength range of 460 nm to 480 nm in a spectral reflectance curve.   The honeycomb structure according to claim 1 or 2, wherein a spectral reflectance in a wavelength range of 360 nm to 740 nm on the exposed surface is 5% to 25%.   A gas processing apparatus comprising the honeycomb structure according to any one of claims 1 to 3 in a case to which an exhaust pipe is connected.

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