WO2015080255A1

WO2015080255A1 - Honeycomb structure, and gas treatment device provided therewith

Info

Publication number: WO2015080255A1
Application number: PCT/JP2014/081592
Authority: WO
Inventors: 徳留　修
Original assignee: 京セラ株式会社
Priority date: 2013-11-29
Filing date: 2014-11-28
Publication date: 2015-06-04

Abstract

[Problem] To provide a honeycomb structure in which the generation of cracks, which is caused by the thermal stress when repeatedly burning and removing collected fine particles, is inhibited as a consequence of the honeycomb structure exhibiting high thermal shock resistance. To also provide a gas treatment device provided with said honeycomb structure. [Solution] A honeycomb structure (1) provided with an outer wall (2), multiple partitioning walls (3) disposed on the inside of the outer wall (2), and a sealing material (4), wherein: spaces surrounded by the outer wall (2) and the partitioning walls (3) or by the partitioning walls (3) function as circulation paths (5) for a fluid; the flow inlets or the flow outlets of the circulation paths (5) are sealed by means of the sealing material (4); the partitioning walls (3) are formed from a sintered body which contains aluminum titanate as the main component; and the X-ray strength of the (101) surface of the partitioning wall crystal, which is the crystal of aluminum titanate, is higher than the X-ray strength of the (230) surface in a first cross-section which is cut along the circulation paths (5) so that the circulation paths (5) become divided.

Description

Honeycomb structure and gas processing apparatus including the same

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 made of a honeycomb structure is used to collect fine particles contained in exhaust gas generated from an internal combustion engine, an incinerator, a boiler, and the like.

As such a filter, Patent Document 1 discloses a honeycomb filter made of aluminum titanate having a columnar aluminum titanate having an aspect ratio (= number average major axis diameter / number average minor axis diameter) of 1.3 or more, and an aspect ratio. Granular titanium titanate having a ratio of less than 1.3 is used by mixing in a weight ratio of columnar aluminum titanate: particulate aluminum titanate to a ratio in the range of 95: 5 to 60:40. A honeycomb filter in which the number average major axis diameter of aluminum oxide is smaller than the number average minor axis diameter of columnar aluminum titanate has been proposed.

Japanese Unexamined Patent Publication No. 2011-6285

Generally, such a honeycomb structure is regenerated by burning and removing fine particles collected and deposited. Therefore, in recent years, there has been a demand for a honeycomb structure in which generation of cracks due to thermal stress when combustion removal is repeated is suppressed.

Therefore, the present invention provides a honeycomb structure in which cracking due to thermal stress is suppressed when the collected particulates are repeatedly burned and removed by having a high thermal shock resistance, and a gas including the honeycomb structure. It is an object to provide a processing apparatus.

A honeycomb structure of the present invention includes an outer wall, a plurality of partition walls provided on the inner side of the outer wall, and a sealing material, and the outer wall and the partition wall or a space surrounded by the partition walls is a fluid. A honeycomb structure in which an inflow port or an outflow port of the flow passage is sealed with the sealing material, and the partition wall is made of a sintered body mainly composed of aluminum titanate, The X-ray intensity of the (101) plane of the partition crystal, which is a crystal of aluminum titanate in the first section cut along the flow path so that the flow path is divided, is the X-ray intensity of the (230) plane. It is characterized by being higher than.

The gas treatment apparatus 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 gas introduction pipe is connected.

According to the honeycomb structure of the present invention, since it has high thermal shock resistance, it is possible to suppress the occurrence of cracks due to thermal stress when the collected particulates are repeatedly burned and removed.

In addition, according to the gas treatment device of the present invention, when the exhaust gas introduction pipe is connected, the honeycomb structure of the present invention is provided in the case, so that the collected particulates are repeatedly burned and removed. Since cracks due to thermal stress are less likely to occur, the reliability is high and fine particles can be collected efficiently over a long period of time.

An example of the honeycomb structure of the present embodiment is shown, in which (a) is a perspective view and (b) is a cross-sectional view taken along line B-B ′ in (a). An example of the end face of the honeycomb structure of the present embodiment is shown, (a) is a partially enlarged view on the inlet side, and (b) is a partially enlarged view on the outlet side. Another example of the end face of the honeycomb structure of the present embodiment is shown, (a) is a partially enlarged view on the inflow side, and (b) is a partially enlarged view on the outflow side. It is a schematic sectional drawing of the gas treatment apparatus which shows an example of this embodiment typically.

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

Fig. 1 (a) is a perspective view showing an example of the honeycomb structure of the present embodiment, and Fig. 1 (b) is a cross-sectional view taken along the line B-B 'in Fig. 1 (a).

The honeycomb structure 1 in the example shown in FIGS. 1A and 1B includes an outer wall 2, a plurality of partition walls 3 provided inside the outer wall 2, and a sealing material 4. The partition wall 3 or a space surrounded by the partition walls 3 serves as a fluid flow path 5, and the inlet or outlet of the flow path 5 is sealed with a sealing material 4. The inflow passage 5 has an inflow port opened and an outflow port sealed with a sealing material 4a, and an outflow port opened and the inflow port sealed with a sealing material 4b. The flow passage 5a and the flow passage 5b are arranged adjacent to each other. And 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.

As the flow of the exhaust gas (EG), the EG that has entered the flow passage 5a that is open on the inlet side is indicated by an arrow because the outlet side of the flow passage 5a is sealed by the sealing material 4a. In this way, the liquid flows out from the adjacent flow passage 5b through the partition wall 3 toward the outflow side. The fine particles contained in the EG are mainly collected by the partition walls 3 in such a flow.

In the honeycomb structure 1 of the present embodiment, the partition wall 3 is made of a sintered body mainly composed of aluminum titanate, and is cut along the flow path 5 so that the flow path 5 is divided. The X-ray intensity of the (101) plane of the partition crystal, which is an aluminum titanate crystal in the cross section, is higher than the X-ray intensity of the (230) plane. In addition, the 1st cross section cut | disconnected along the flow path 5 so that the flow path 5 may be divided with the cross section cut | disconnected along the axial direction A shown to Fig.1 (a), ie, FIG. It is the cross section of the partition 3 as shown to b).

Since the honeycomb structure 1 of the present embodiment satisfying such a configuration has high thermal shock resistance, cracks generated in the partition walls 3 can be suppressed when the collected particulates are repeatedly burned and removed. Note that, when the first cross section is observed, there is a partition crystal in which micro cracks are confirmed, and the presence of the partition crystal in which micro cracks are confirmed can cause high thermal shock resistance. This is considered to be due to the effect of relaxing the thermal stress due to the difference in the linear expansion coefficient between the axial direction A and the radial direction in FIG.

In the partition crystal in the first cross section, when the X-ray intensity of the (230) plane is I ₂₃₀ and the X-ray intensity of the (101) plane is I ₁₀₁ , the value of I ₁₀₁ / I ₂₃₀ is 1.2 or more and 1.6. It is preferable that: When satisfying such a configuration, the anisotropy of linear expansion between the axial direction A and the radial direction in the partition wall 3 is reduced. Therefore, the difference in the linear expansion coefficient between the axial direction A and the radial direction of the partition wall 3 is reduced, and the generation of cracks due to thermal stress when the collected particulates are repeatedly removed by combustion can be suppressed.

Further, in the partition crystal in the first cross section, when the X-ray intensity of the (002) plane is I ₀₀₂ and the X-ray intensity of the (230) plane is I ₂₃₀ , the value of I ₀₀₂ / (I ₀₀₂ + I ₂₃₀ ) Is preferably 0.33 or more and 0.39 or less. When such a configuration is satisfied, the anisotropy of linear expansion between the axial direction A and the radial direction in the partition wall 3 is further reduced. Therefore, the effect of suppressing the occurrence of cracks due to thermal stress when the collected particulates are repeatedly removed by combustion is further enhanced.

In the partition crystal in the first cross section, when the X-ray intensity of the (101) plane is I ₁₀₁ and the X-ray intensity of the (002) plane is I ₀₀₂ , the value of I ₀₀₂ / I ₁₀₁ is 0.36 or more and 0.50. It is preferable that: When such a configuration is satisfied, the honeycomb structure 1 has a high mechanical strength in the radial direction and the pressure loss is hardly increased. In addition, it is possible to further suppress the occurrence of cracks due to thermal stress when the collected fine particles are repeatedly burned and removed.

Next, the sealing material 4 is made of a sintered body mainly composed of aluminum titanate, and is a sealing material crystal that is an aluminum titanate crystal in the second cross section along the flow path 5 of the honeycomb structure 1. It is preferable that the X-ray intensity of the P (101) plane is higher than the X-ray intensity of the P (230) plane. In order to identify the Miller index and the X-ray intensity in the partition crystal and the encapsulant crystal, P is assigned to the mirror index of the encapsulant crystal, and the X-ray intensity of each mirror index of the encapsulant crystal is I. _P is attached. The second cross section has the same cutting direction as the first cross section.

In such a configuration, since the sealing material 4 has high thermal shock resistance, cracks generated between the sealing material crystals constituting the sealing material 4 when the collected particulates are repeatedly burned and removed. Can be suppressed. In addition, when the second cross section is observed, there is a sealing material crystal in which microcracks are confirmed, and the sealing material crystal in which microcracks are confirmed can have high thermal shock resistance. This is considered to be due to the action of relaxing thermal stress due to the difference in the linear expansion coefficient between the axial direction A and the radial direction in the sealing material 4 due to the presence.

In addition, since the sealing material 4 has high thermal shock resistance as described above, not only can the crack of the sealing material 4 itself be suppressed, but also the inlet side where the sealing material 4 is provided or Since the progress of cracks to the partition wall 3 in the vicinity of the outflow port can be suppressed, the thermal shock resistance of the honeycomb structure 1 can be enhanced.

In the encapsulant crystal in the second cross section, when the X-ray intensity of the P (230) plane is I _P230 and the X-ray intensity of P (101) is I _P101 , the value of I _P101 / I _P230 is It is preferable that it is 1.8 or more and 2.5 or less. When satisfying such a configuration, the anisotropy of linear expansion between the axial direction A and the radial direction in the sealing material 4 is reduced. Therefore, it is possible to suppress the occurrence of cracks due to thermal stress when the collected fine particles are repeatedly removed by combustion.

In the encapsulant crystal in the second cross section, when the X-ray intensity of the P (002) plane is I _P002 and the X-ray intensity of the P (230) plane is I _P230 , I _P002 / (I _P002 + I The value of _P230 ) is preferably from 0.12 to 0.18. In such a configuration, the anisotropy of linear expansion between the axial direction A and the radial direction in the sealing material 4 is further reduced. Therefore, the effect of suppressing the generation of cracks due to thermal stress when the collected fine particles are repeatedly burned and removed becomes higher.

Further, the sealing material crystal in the second section, the X-ray intensity of P (101) plane and _{I P101,} when the X-ray intensity of P (002) plane was _{I _P002,} the value of I P002 _{/ I P101} Is preferably 0.05 or more and 0.30 or less. When satisfying such a configuration, the mechanical strength in the radial direction of the honeycomb structure 1 in the sealing material 4 is increased. Therefore, in particular, the diameters of the inlet and outlet of the honeycomb structure 1 where the sealing material 4 is located. The mechanical strength in the direction is further increased.

Further, on the outflow side, I ₂₃₂ / (I ₂₃₂ + I when the X-ray intensity of the (232) plane of the partition crystal in the first cross section is I ₂₃₂ and the X-ray intensity of the (230) plane is I _230. the value of _230), a second X-ray intensity of P (232) plane of the sealing material crystal and _{I P232} in cross section, P (230) when the X-ray intensity of the plane was _{_I P230 I} _P232 / ( It is preferable that the value of I _P232 + I _P230 ) is different. In such a configuration, since the inclination of the lattice planes of the partition crystal and the sealing material crystal are different, the partition crystal and the sealing material crystal between the partition 3 and the sealing material 4 are used. Means that the trapped particulate matter is repeatedly burnt and removed between the partition wall 3 and the sealing material 4 on the outlet side where the collected amount of particulates is relatively larger than the inlet side. It becomes difficult to produce a gap, and excellent collection efficiency can be maintained over a long period of time.

In addition, the main component in the sintered compact which comprises the partition 3 and the sealing material 4 is a component of content larger than 50 mass% among 100 mass% of all the components which comprise a sintered compact. Identification of the crystal structure of the component constituting the sintered body may be performed using an X-ray diffractometer and collated with a JCPDS card. Further, the content may be obtained by measuring using an ICP emission spectroscopic analyzer or a fluorescent X-ray analyzer and converting it according to the identified component. Further, in the first cross section and the second cross section What is necessary is just to measure the X-ray intensity in each surface of a partition crystal or a sealing material crystal using an X-ray diffractometer.

FIGS. 2 (a) and 3 (a) are partially enlarged views on the inlet side, showing an example of the end face of the honeycomb structure of the present embodiment, and FIGS. 2 (b) and 3 (b) are flow diagrams. It is the elements on larger scale by the side of an exit. The opening shape of the flow passage 5a at the end face shown in FIG. 2A is an octagonal shape, and the opening shape of the flow passage 5b at the end face shown in FIG. 2B is a square shape. Moreover, the opening shape of the flow path 5a in the end surface shown in FIG. 3A is a flat hexagonal shape, and the opening shape of the flow path 5b in the end surface shown in FIG. 3B is a regular hexagonal shape. 2 (a) and 2 (b) are partially enlarged views of the inflow side and the outflow side of one honeycomb structure, and the flow path 5a is opened more than the flow path 5b. An example of a large area is shown. FIGS. 3A and 3B are views in which the inlet side and the outlet side of one honeycomb structure are partially enlarged, and the flow passage 5b is opened more than the flow passage 5a. An example of a large area is shown.

In the shape shown in FIGS. 2A and 2B, the diameter of the flow passage 5a opened on the inlet side is 1.55 times or more and 1.95 times or less than the diameter of the flow passage 5b opened on the outlet side. It is preferable that Thus, when the diameter ratio is 1.55 times or more and 1.95 times or less, the respective surface areas of the partition wall 3 and the sealing material 4 capable of adsorbing the fine particles can be increased while maintaining the mechanical strength. Therefore, the amount of collected fine particles can be increased. Here, the diameter of each of the flow passages 5a and 5b is a diameter of an inscribed circle in contact with the partition wall 3 on the end surface on the inlet side, and is measured using an optical microscope with a magnification of, for example, 50 times to 100 times. can do.

Further, when the relationship between the shape and size shown in FIGS. 3A and 3B is satisfied, that is, the flow passage 5b has a larger opening area than the flow passage 5a, and the inflow side is opened. The flow passage 5a has a flat hexagonal shape, the flow passage 5b sealed on the inlet side has a regular hexagonal shape, and the inlet side opens to surround each side of the flow passage 5b sealed on the inlet side. When the path 5b is disposed, the mechanical strength in the radial direction is excellent, and the amount of collected fine particles can be increased.

Here, the sintered body mainly composed of aluminum titanate constituting the partition walls 3 and the sealing material 4 of the honeycomb structure 1 of the present embodiment includes magnesium and iron, and the magnesium titanate crystal includes magnesium and iron. Is preferably dissolved. When magnesium is dissolved in aluminum titanate crystals, it is possible to suppress a decrease in corrosion resistance of sulfur oxide fine particles formed by oxidation of sulfur contained in EG. Moreover, when iron is dissolved in the crystal of aluminum titanate, it is possible to suppress deterioration in heat resistance deterioration due to adhesion of sulfur oxide fine particles formed by oxidation of sulfur contained in EG.

In addition, magnesium and iron are values converted into magnesium titanate and iron titanate in 100% by mass of all components constituting the sintered body mainly composed of aluminum titanate. It is preferable to include the following. The content when magnesium is converted to magnesium titanate and the content when iron is converted to iron titanate are the contents of Mg and Fe using an ICP emission spectrometer or an X-ray fluorescence analyzer. _May be converted into MgTiO ₃ (magnesium titanate) and Fe ₂ TiO ₅ (iron titanate), respectively.

Whether magnesium or iron is dissolved in the aluminum titanate crystal is determined using a scanning electron microscope or transmission electron microscope equipped with an energy dispersive X-ray spectrometer. This refers to the case where magnesium or iron is confirmed when X-rays are irradiated.

In the sintered body mainly composed of aluminum titanate, it is preferable that silicon oxide is present between crystals of aluminum titanate. This is because silicon oxide can strongly bond aluminum titanate crystals to each other, suppress abnormal grain growth of aluminum titanate crystals, and increase mechanical strength. In particular, the silicon oxide is preferably 0.4% by mass or more and 1.2% by mass or less in terms of SiO ₂ out of 100% by mass of all components constituting a sintered body mainly composed of aluminum titanate, for example. is there.

Incidentally, the partition walls 3 in the honeycomb structure 1 of the present embodiment preferably have a porosity of 38% to 56% and an average pore diameter of 5 μm to 26 μm. When the porosity and average pore diameter of the partition walls 3 are within this range, an increase in pressure loss can be suppressed. Moreover, it is preferable that the sealing material 4 has a porosity of 50% to 65% and an average pore diameter of 12 μm to 18 μm. In addition, what is necessary is just to obtain | require the porosity and average pore diameter of the partition 3 and the sealing material 4 based on the mercury intrusion method.

Moreover, it is preferable that the sealing material 4a for sealing the outflow port in the honeycomb structure 1 of the present embodiment has a smaller area ratio of the grain boundary phase than the sealing material 4b for sealing the inflow port. In particular, the difference in the area ratio of the grain boundary phase is preferably 0.4% or more and 0.8% or less. The honeycomb structure 1 collects most of the fine particles by the partition walls 3 when collecting the fine particles, but also collects the fine particles by the sealing material 4a that seals the outlet. Therefore, when the collected fine particles are burned and removed, the temperature of the sealing material 4a that seals the outlet is likely to be higher than that of the inlet. At this time, when the configuration is as described above, since the area ratio of the grain boundary phase of the sealing material 4a for sealing the outlet is small, the heat resistance is improved and the temperature at the time of combustion removal can be endured. .

Here, in order to obtain the area ratio of the grain boundary phase, first, a reflected electron image is taken using a scanning electron microscope with respect to a cross-section obtained by mirror finishing the sealing material 4a and the sealing material 4b. Then, the crystal phase and the grain boundary phase are binarized using the photographed image, and the ratio of the area of the grain boundary phase to the area of 100% of the total area of the crystal phase and the grain boundary phase is expressed as the area ratio of the grain boundary phase. And it is sufficient. In obtaining the area ratio of the grain boundary phase, the part not including pores is photographed. As photographing conditions, for example, the magnification is 3000 times, and the photographing range is 18 μm in width and 12 μm in length. You can do it.

Further, such a honeycomb structure 1 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 (radial direction) perpendicular to A is 5 to 124 per 100 mm ² (32 to 800 CPSI). Moreover, the thickness of the partition 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.

The effective filtration area of the honeycomb structure 1 is preferably 1.1 m ² / L or more from the viewpoint of reducing both the pressure loss caused by repeated collection and the thermal stress caused by burning fine particles. More preferably, it is 1.4 m ² / L or more. In addition, the upper limit of an effective filtration area is 2.0 m < ² > / L, for example. 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 honeycomb structure 1L (liter).

FIG. 4 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. 4, the honeycomb structure 1 of the present embodiment is accommodated in the case 8 with the outer periphery held by the gripping material 7, and the diesel engine is placed in the inlet 8 a of the case 8. An EG introduction pipe 9 communicating with an internal combustion engine (not shown) such as a gasoline engine is connected, and an exhaust pipe (not shown) is connected to the outlet 8b. Here, the gripping material 7 is preferably a heat insulating material. In this case, heat generated in the honeycomb structure 1 is transferred to the case 8 due to combustion removal of the fine particles, and the case 8 is deformed or deteriorated. Can be suppressed.

Note that 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, and has a central portion formed in a cylindrical shape and both end portions formed in a truncated cone shape.

Further, the honeycomb structure 1 of the present embodiment can use not only exhaust gas which is gas but also liquid. For example, clean water or sewage can be used as the fluid, and the gas treatment device 100 of the present embodiment can also be applied for liquid filtration.

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

In order to obtain a ceramic powder for forming the honeycomb structure 1 of the present embodiment, first, dry mixing is performed on a blended raw material prepared by mixing 53 to 59% by mass of aluminum oxide powder and the remainder as titanium oxide powder. Get the next raw material. Next, the obtained primary raw material is calcined at 1435 ° C. or higher and 1560 ° C. or lower in an air atmosphere for 1 hour or more and 5 hours or less to obtain a ceramic powder composed of pseudo-brookite type aluminum titanate crystals. (First calcined powder) is obtained.

As another example for obtaining the ceramic powder for forming the honeycomb structure 1, aluminum oxide powder is 36 to 42% by mass, magnesium oxide powder is 9 to 15% by mass, and the remainder is titanium oxide powder. The prepared raw material is dry-mixed to obtain a primary raw material. Next, the obtained primary material is calcined at 1435 ° C or higher and 1560 ° C or lower for 1 hour to 5 hours in an air atmosphere, whereby pseudo brookite in which magnesium is dissolved in aluminum titanate crystals. A ceramic powder (second calcined powder) made of type crystals can be obtained.

As still another example for obtaining the ceramic powder forming the honeycomb structure 1, first, 27 to 33% by mass of aluminum oxide powder, 7 to 13% by mass of magnesium oxide powder, ferric oxide A primary raw material is obtained by dry-mixing the prepared raw material prepared by mixing 13 to 17% by mass of the above powder and the remainder as titanium oxide powder. Next, the obtained primary raw material is calcined in an air atmosphere at a temperature of 1435 ° C. or higher and 1560 ° C. or lower and held for 1 hour or longer and 5 hours or shorter, so that magnesium and iron are solidified into aluminum titanate crystals. A ceramic powder (third calcined powder) made of melted pseudo-brookite crystals can be obtained.

If magnesium or iron can be dissolved in the crystal of aluminum titanate, powders such as carbonates, hydroxides, and nitrates are used in addition to magnesium oxide powder and ferric oxide powder. Alternatively, powders of these compounds may be used. Further, it is more preferable that each powder used for obtaining the primary raw material has a purity of 99.0% by mass or more, particularly 99.5% by mass or more.

Next, the calcined powder obtained using an electric grinding machine in which a fixed grindstone and a rotating grindstone are arranged facing each other in the vertical direction is crushed, and a stainless steel product having a particle size defined by JIS R 6001: 1998 is F150. Mesh pass using mesh. As the crushing conditions, for example, the grindstone particle size, the grindstone material, the distance between the grinding surfaces of the grindstone, and the rotational speed of the rotating grindstone are F24 to F46, aluminum oxide, 100 μm or less (excluding 0 μm), 100 rpm. If it is 700 rpm or less, a ceramic powder having a D ₅₀ particle size of 50 μm or more and 80 μm or less can be obtained. Here, the interval between the grinding surfaces of the grindstone is preferably 33 μm or more and 47 μm or less.

For example, silicon oxide powder having an average particle diameter of 1 to 3 μm and an addition amount of 0.4 to 1.2 parts by mass with respect to 100 parts by mass of the ceramic powder. And a pore-forming agent such as graphite, starch or polyethylene resin having an average particle size of 10 μm to 25 μm and an addition amount of 1 to 13 parts by mass with respect to 100 parts by mass of the ceramic powder. .

Then, further add a plasticizer, a slip agent, water, etc., and mix and stir using a universal stirrer, rotary mill or V-type stirrer. Thereafter, the mixture is kneaded using a three-roll mill or a kneader to obtain a plasticized clay.

Here, in the partition wall 3, the X-ray intensity of the (101) plane of the aluminum titanate crystal of the partition wall 3 in the first section cut along the flow path 5 so that the flow path 5 is divided is ( 230) In order to obtain a honeycomb structure 1 having a higher X-ray intensity than the plane, the durometer hardness specified in JIS K 6253-2012 should be A47 or higher.

In the partition crystal in the first cross section, when the X-ray intensity of the (230) plane is I ₂₃₀ and the X-ray intensity of the (101) plane is I ₁₀₁ , the value of I ₁₀₁ / I ₂₃₀ is 1.2 or more and 1.6. In order to obtain the following honeycomb structure 1, the durometer hardness may be set to A48 or more and A52 or less.

Further, in the partition crystal in the first cross section, when the X-ray intensity of the (002) plane is I ₀₀₂ and the X-ray intensity of the (230) plane is I ₂₃₀ , the value of I ₀₀₂ / (I ₀₀₂ + I ₂₃₀ ) However, in order to obtain the honeycomb structure 1 that is 0.33 or more and 0.39 or less, the durometer hardness may be set to A49 or more and A51 or less. The hardness of the clay may be adjusted by appropriately adjusting the amount of slip agent added.

Next, this clay is molded by an extruder equipped with a screw. This extrusion molding machine is equipped with a mold, and the mold has an inner diameter that determines the outer diameter of the molded body, for example, 155 mm or more and 300 mm or less, and is used to form the outer wall 2 and the partition walls 3 of the honeycomb structure 1. Has a slit.

Then, the clay is put into an extrusion molding machine equipped with a molding die as described above, pressure is applied to produce a honeycomb-shaped molded body, and the obtained molded body has a predetermined length, for example, 170 mm or more and 180 mm or less. Disconnect.

In the partition crystal in the first cross section, when the X-ray intensity of the (101) plane is I ₁₀₁ and the X-ray intensity of the (002) plane is I ₀₀₂ , the value of I ₀₀₂ / I ₁₀₁ is 0.36 or more and 0.50 or less. In order to obtain a certain honeycomb structure 1, the molding pressure at the time of extrusion molding may be 6 MPa or more and 15 MPa or less.

Then, after spraying grease on the outer peripheral surface of the outer wall of the cut molded body, the molded body is mounted so that the axial direction A is perpendicular to the mounting surface, and dried by a microwave dryer.

Next, the sealing material 4 for alternately sealing each of the inlet side and the outlet side of the plurality of flow paths 5 of the dried body obtained by drying the formed body is prepared. Specifically, first, masking is performed on a portion where the sealing material 4a is not formed on the end surface (OF) on the outlet side. And after winding the strip | belt-shaped body with the full length longer than the outer periphery of a dry body around the outer peripheral side of the dry body, and fixing a strip | belt body to a dry body with an adhesive tape, a fusion | melting tape, or an adhesive tape, the outlet of a dry body The end face side is immersed in a slurry stored in a cylindrical container.

Here, the slurry is an oxidation in which one of the above-described ceramic powders has, for example, an average particle size of 1 μm or more and 3 μm or less and an addition amount of 0.4 parts by mass or more and 1.2 parts by mass or less with respect to 100 parts by mass of the ceramic powder. After adding silicon 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 ceramic powder, add a dispersant and water. Obtained by mixing. The strip-shaped body is made of, for example, a foamed polyethylene sheet, kraft paper whose surface is covered with a propylene resin, and the thickness is preferably 1 mm or more and 3 mm or less.

Next, after the dried body in which the end surface on the outlet side is immersed in the slurry is taken out from the container and dried, the end surface on the inlet side of the dried body is immersed in the slurry in the same manner as described above. Then, after drying the slurry to be the sealing material 4b on the end face side on the inlet side, the slurry is put in a firing furnace and held at a temperature of 1380 ° C. to 1500 ° C. for 2 to 10 hours, whereby the honeycomb of this embodiment The structure 1 can be obtained.

In addition, the honeycomb structure 1 in which the X-ray intensity of the P (101) plane of the sealing material crystal in the second cross section cut along the flow path 5 is higher than the X-ray intensity of the P (230) plane is obtained. For this, the viscosity of the slurry at room temperature may be 0.8 Pa · s or more. The viscosity of the slurry may be adjusted by appropriately adjusting the amount of the dispersant with respect to the amount of water.

In the encapsulant crystal in the second cross section, when the X-ray intensity of the P (230) plane is I _P230 and the X-ray intensity of P (101) is I _P101 , the value of I _P101 / I _P230 is In order to obtain the honeycomb structure 1 that is 1.8 or more and 2.5 or less, the viscosity of the slurry may be 2 Pa · s or more and 2.6 Pa · s or less.

In the encapsulant crystal in the second cross section, when the X-ray intensity of the P (002) plane is I _P002 and the X-ray intensity of the P (230) plane is I _P230 , I _P002 / (I _P002 + I the value of _P230) to obtain a honeycomb structure 1 is 0.12 or more 0.18 or less, the viscosity of the slurry may be less 2.1 Pa · s or more 2.5 Pa · s.

Further, in the encapsulant crystal in the second cross section, when the X-ray intensity of the P (101) plane is I _P101 and the X-ray intensity of the P (002) plane is I _P002 , the value of I _P002 / I _P101 In order to obtain the honeycomb structure 1 having a thickness of 0.05 or more and 0.30 or less, after dipping in the slurry, a pressure of 0.02 MPa or more and 0.03 MPa or less may be applied to the end surface of the dipped one.

Further, on the outflow side, I ₂₃₂ / (I ₂₃₂ + I when the X-ray intensity of the (232) plane of the partition crystal in the first cross section is I ₂₃₂ and the X-ray intensity of the (230) plane is I _230. the value of _230), a second X-ray intensity of P (232) plane of the sealing material crystal and _{I P232} in cross section, P (230) when the X-ray intensity of the plane was _{_I P230 I} _P232 / ( In order to obtain the honeycomb structure 1 having a value different from the value of I _P232 + I _P230 ), the end surface on the outlet side is immersed in the slurry, and then the molding pressure of 0.0022 to 0.0026 at the end of the extrusion is applied to the end surface on the outlet side. Double pressure should be applied. For example, when the molding pressure at the time of extrusion molding is 10 MPa, the pressure applied to the end surface on the outlet side may be 0.022 MPa or more and 0.026 MPa or less. _Thus, the value of _{_{I 232 / (I 232 + I}} 230) _is smaller than the value of _{_{I P232 / (I P232 + I}} P230).

In addition, the gas treatment device 20 of the present embodiment accommodates the introduction pipe 9 in the flow of the case 8 after the outer periphery of the honeycomb structure 1 manufactured by the above-described method is accommodated in the case 8 while being held by the holding material 7. It can be obtained by connecting the exhaust pipe to the inlet 8a and the outlet 8b of the case 8 respectively.

Although the honeycomb structure 1 of the present embodiment has been described by taking as an example the case where it is used in the gas treatment device 20 that repeatedly burns and removes the collected fine particles, the honeycomb structure 1 of the present embodiment It can also be used without any problem in a gas processing apparatus that continuously burns and removes the collected fine particles.

Hereinafter, examples of the present invention will be described in detail, but the present invention is not limited to these examples.

First, dry mix the compounded raw material prepared by mixing 30% by mass of aluminum oxide powder, 10% by mass of magnesium oxide powder, 15% by mass of ferric oxide powder and the remainder of titanium oxide powder, Obtained. Here, the purity of each powder was 99.5% by mass.

Next, the obtained primary raw material is calcined at a temperature of 1450 ° C. in an air atmosphere for 3 hours and calcined, so that a temporary quackiteite crystal in which magnesium and iron are dissolved in aluminum titanate is obtained. A baked powder was obtained.

Then, the calcined powder obtained using an electric grinding machine (Mascoloyder (registered trademark) manufactured by Masuko Sangyo Co., Ltd.) in which a fixed grindstone and a rotating grindstone are arranged facing each other in the vertical direction is crushed, and JIS R 6001 : A ceramic powder having a D ₅₀ of 58 μm was obtained by mesh passing using a stainless steel mesh having a particle size defined by 1998 of F150. Here, the grain size of the grindstone was 36.7 mm, the material of the grindstone was aluminum oxide, the spacing between the grinding surfaces of the grindstone was F36, and the rotational speed of the rotating grindstone was 400 rpm. The D ₅₀ of the obtained ceramic powder was measured according to the laser diffraction method described in JIS Z 8825-1: 2001 (ISO13320-1: 1999).

The obtained ceramic powder has an average particle size of 2 μm and an addition amount of 0.8 parts by mass with respect to 100 parts by mass of the ceramic powder, and an average particle size of 15 μm, 7 parts by mass of polyethylene resin, plasticizer, slip agent, and water were added to 100 parts by mass of the powder, and mixed and stirred using a universal stirrer. Thereafter, the mixture was kneaded using a kneader to obtain a plasticized clay. The hardness of the clay was adjusted as appropriate by the amount of the slip agent added, and the hardness of the clay used for each sample was as shown in Table 1. Here, the hardness of the clay shown in Table 1 is a durometer hardness value measured in accordance with JIS K 6253-2012.

Next, the inner diameter for determining the outer diameter of the formed body is 170 mm, and the clay is put into a screw type extrusion molding machine equipped with a forming die having slits for forming the outer wall and partition walls of the honeycomb structure. And a pressure of 18 MPa was applied to produce a honeycomb-shaped formed body. The obtained formed body was cut at a length of 175 mm, and a second formed body was cut at a length of 12 mm. And made.

And after spraying grease on the outer peripheral surface of each outer wall of the cut first molded body and second molded body, each molded body is mounted so that the axial direction A is perpendicular to the mounting surface. And dried with a microwave dryer to obtain a first dried body and a second dried body.

Next, in order to form a sealing material that alternately seals the inlet side and the outlet side of the plurality of flow passages of the first dry body, first, the sealing material is applied to the end surface on the outlet side. Masking was done on the part that was not formed. And after winding the strip | belt-shaped body whose full length is longer than the outer periphery of a 1st dry body around the outer periphery by the side of the outflow port of a 1st dry body, after fixing a strip | belt-shaped body to a 1st dry body with an adhesive tape, 1st The end face on the outlet side of the dried body was immersed in slurry previously stored in a cylindrical container. At this time, the height of the liquid surface of the slurry was 4.2 mm. Moreover, the clearance gap between the inner periphery of a container and the outer periphery of a strip | belt shaped object was 20 mm.

The slurry is a ceramic 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 ceramic powder, and an addition amount with respect to 100 parts by mass of the ceramic powder. 7 parts by mass of starch, a dispersant, and water were added and mixed. The viscosity of this slurry was 1.8 Pa · s. And the thing which is 2 mm in thickness and consists of a foaming polyethylene sheet was used for the strip | belt shaped object.

Next, after drying the slurry that has entered the end surface on the outlet side, a belt-like body having a longer overall length than the outer periphery of the first dried body is wound around the outer periphery of the first dried body on the inlet side, and an adhesive tape After fixing the belt-like body to the first dry body by the above, the end face on the inlet side of the first dry body was immersed in the slurry stored in the cylindrical container.

And after drying the slurry infiltrated into the end face on the inlet side, the first and second dried bodies are fired by holding them at a firing temperature of 1380 ° C. for 3 hours using an electric furnace. Sample No. 1-9 were obtained. A sample obtained by firing the first dried body (hereinafter referred to as test piece 1) has a length L in the axial direction A shown in FIG. 1 of 152 mm, and a sample obtained by firing the second dried body ( Hereinafter, it is referred to as a test piece 2. The length L in the axial direction A shown in FIG. 1 is 10 mm, and the number of the flow passages 5 in the first cross section per unit area is 300 CPSI. Sample No. The porosity of the partition walls 1 to 9 was determined by mercury porosimetry and found to be 50% by volume.

Next, a first cross section cut along the flow path is formed using the test piece 2 so that the flow path is divided, and an aluminum titanate having the first cross section is formed using an X-ray diffractometer. The X-ray intensities of the (101) plane, (230) plane and (002) plane of the partition crystal, which is a crystal of, were measured, and I ₁₀₁ / I ₂₃₀ and I ₀₀₂ / (I ₀₀₂ + I ₂₃₀ ) were calculated. _The value of I 101 _{/ I 230} is the sample is greater than 1 is that the higher the X-ray intensity of the X-ray intensity (230) plane of the (101) plane.

Furthermore, a crack confirmation test was performed using the test piece 1. Specifically, 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 / Then, the particulate matter was collected in the honeycomb structure, and then regeneration was performed by burning and removing the collected particulate matter under the conditions of a combustion temperature of 1250 ° C. and a combustion time of 10 minutes. This collection and regeneration was defined as one cycle, and this cycle was repeated. After regeneration, the partition walls were visually observed, and the number of cycles in which cracks were first confirmed was shown in Table 1.

As shown in Table 1, sample no. 2 to 9 are sample Nos. The number of cycles in which cracks were confirmed was larger than 1, the partition wall was made of a sintered body mainly composed of aluminum titanate, and the X-ray intensity of the (101) plane of the partition crystal in the first cross section was It was found that the occurrence of cracks due to thermal stress can be suppressed by being higher than the X-ray intensity of the (230) plane.

Further, when the X-ray intensity of the (230) plane is I ₂₃₀ and the X-ray intensity of the (101) plane is I ₁₀₁ , if the value of I ₁₀₁ / I ₂₃₀ is 1.2 or more and 1.6 or less, cracks due to thermal stress It has been found that the generation of water can be further suppressed (Sample Nos. 3 to 7).

Furthermore, it was found that if the value of I ₀₀₂ / (I ₀₀₂ + I ₂₃₀ ) is 0.33 or more and 0.39 or less, the occurrence of cracks due to thermal stress can be further suppressed (Sample Nos. 4 to 6).

Except that the molding pressure at the time of extrusion molding was changed to the molding pressure shown in Table 2, sample No. Sample No. 5 was prepared by the same method as that used to manufacture sample No. 5. 10-15 were obtained.

Thereafter, as in Example 1, the first cross section was formed, and the X-ray intensities of the (002) plane and (101) plane of the partition crystal in the first cross section were measured using an X-ray diffractometer, I ₀₀₂ / I ₁₀₁ was calculated.

Further, a cubic specimen having a side length of 10 mm was cut out from only the partition wall of each sample, and the compressive strength in the radial direction of the honeycomb structure was measured in accordance with JASO M 505-87.

In addition, after connecting the end face on the inlet side of each sample to a carbon generator (manufactured by Nippon Kanomax Co., Ltd., model S4102), dry air containing fine particles from this device at a temperature of 25 ° C. is flowed per unit time. 2.27 Nm ³ / min was injected toward each sample, and the rise in pressure loss at the outlet end face relative to the pressure loss at the inlet end face at this time was calculated. A manometer was used to measure the pressure loss. Using. Furthermore, a crack confirmation test was performed in the same manner as in Example 1. The results are shown in Table 2.

As shown in Table 2, in the partition crystal in the first cross section, when the X-ray intensity of the (101) plane is I ₁₀₁ and the X-ray intensity of the (002) plane is I ₀₀₂ , I ₀₀₂ / I ₁₀₁ If the value is 0.36 or more and 0.50 or less, the mechanical strength in the radial direction is increased, the pressure loss is hardly increased, and the generation of cracks due to thermal stress when repeated removal of the collected fine particles by combustion is further suppressed. (Sample Nos. 11 to 14).

Except that the slurry viscosity at the time of forming the sealing material was set to the value shown in Table 3, sample No. Sample No. 5 was prepared by the same method as that used to manufacture sample No. 5. 16-28 were obtained. The viscosity of the slurry is a value measured according to JIS Z 8803-2011 by appropriately adjusting the amount of the dispersant with respect to water.

Thereafter, a second cross section cut along the flow path of the sealing material is formed using the test piece 2, and the sealing, which is an aluminum titanate crystal in the second cross section, is formed using an X-ray diffractometer. The X-ray intensities of the P (101) plane, the P (230) plane, and the P (002) plane of the stopping material crystal were measured, and I _P101 / I _P230 and I _P002 / (I _P002 + I _P230 ) were calculated. A sample having a value of I _P101 / I _P230 exceeding 1 indicates that the X-ray intensity of the P (101) plane is higher than the X-ray intensity of the P (230) plane.

And the confirmation test of the crack of a sealing material was done by the same method as Example 1. The results are shown in Table 3.

As shown in Table 3, sample No. Samples Nos. 17 to 28 were sample The number of cycles in which cracks were confirmed was greater than 16, the sealing material was made of a sintered body mainly composed of aluminum titanate, and the P (101) plane of the sealing material crystal in the second cross section It has been found that the occurrence of cracks due to thermal stress can be suppressed when the X-ray intensity is higher than the X-ray intensity of the P (230) plane.

Further, when the X-ray intensity of the P (230) plane is _IP230 and the X-ray intensity of the P (101) plane is _IP101 , if the value of _IP101 / _IP230 is 1.8 or more and 2.5 or less, thermal stress It was found that the generation of cracks due to slabs can be further suppressed (Sample Nos. 23 to 27).

_Further, if the value is 0.12 or more 0.18 or less of the _{_{I P002 / (I P002 + I}} P230), it was found to be further suppress the occurrence of cracks due to thermal stress (Sample No.24 ~ 26).

The sample of Example 1 except that the pressure at the time of extrusion was 10 MPa, and the pressure (end face pressure) applied to the end face on the outlet side after the end face on the outlet side was immersed in the slurry was set to the values shown in Table 4 No. Sample No. 5 was prepared by a method similar to the method for producing Sample No. 5. 29-35 were obtained.

Thereafter, as in Example 3, a second cross section is formed, and the X-ray intensities of the P (002) plane and the P (101) plane of the encapsulant crystal in the second cross section are obtained using an X-ray diffractometer. _Was measured and I _P002 / I _P101 was calculated. In addition, a cubic specimen having a side length of 10 mm was cut out from the portion including the sealing material on the end face of each sample, and the compressive strength in the radial direction of the honeycomb structure was measured in accordance with JASO M 505-87. did. Further, a confirmation test for cracks in the sealing material was performed in the same manner as in Example 3. The results are shown in Table 4.

As shown in Table 4, when the X-ray intensity of the P (101) plane is I _P101 and the X-ray intensity of the P (002) plane is I _P002 in the encapsulant crystal in the second cross section, I _P002 If the value of / _IP101 is 0.05 or more and 0.30 or less, the mechanical strength in the radial direction is increased, and the generation of cracks due to thermal stress when repeated removal of the collected fine particles can be further suppressed. (Sample Nos. 30 to 34).

Sample No. Nos. 31 to 33 show that the effect of suppressing the occurrence of cracks is high. On the outlet side of these samples, the X-ray intensity of the (232) plane of the partition crystal in the first section is I ₂₃₂ , The value of I ₂₃₂ / (I ₂₃₂ + I ₂₃₀ ) when the X-ray intensity of the (230) plane is I ₂₃₀ and the X-ray intensity of the P (232) plane of the sealing material crystal in the second cross section are expressed as I _P232 And the value of I _P232 / (I _P232 + I _P230 ) when the X-ray intensity of the P (230) plane is I _P230 , these values were different.

From these results, these values are different, so that even if the collected particulates are repeatedly burned and removed, it is difficult for gaps to form between the partition walls and the sealing material, and excellent collection efficiency is maintained over a long period of time. I found out that I can do it.

1: honeycomb structure 2: outer wall 3: partition wall 4: sealing material 5: flow path 7: gripping material 8: case 9: introduction pipe
20: Gas processing equipment

Claims

An outer wall, a plurality of partition walls provided on the inner side of the outer wall, and a sealing material, wherein the outer wall and the partition wall or a space surrounded by the partition walls serves as a fluid flow path, A honeycomb structure in which an inlet or an outlet is sealed with the sealing material,
The partition wall is made of a sintered body mainly composed of aluminum titanate, and is a partition crystal that is a crystal of aluminum titanate in a first cross section cut along the flow path so that the flow path is divided. A honeycomb structure, wherein the X-ray intensity of the (101) plane is higher than the X-ray intensity of the (230) plane.
In the partition crystal in the first cross section, when the X-ray intensity of the (230) plane is I 230 and the X-ray intensity of the (101) plane is I 101 , the value of I 101 / I 230 is 1. The honeycomb structure according to claim 1, wherein the honeycomb structure is 2 or more and 1.6 or less.
In the partition crystal in the first cross section, when the (002) plane X-ray intensity is I 002 and the (230) plane X-ray intensity is I 230 , I 002 / (I 002 + I 230 ) The honeycomb structure according to claim 1 or 2, wherein the value is 0.33 or more and 0.39 or less.
In the partition crystal in the first cross section, when the X-ray intensity of the (101) plane is I 101 and the X-ray intensity of the (002) plane is I 002 , the value of I 002 / I 101 is 0. The honeycomb structure according to any one of claims 1 to 3, wherein the honeycomb structure is equal to or greater than 0.36 and equal to or less than 0.50.
The sealing material is made of a sintered body mainly composed of aluminum titanate, and is a sealing material crystal that is a crystal of aluminum titanate in a second cross section cut along the flow path of the honeycomb structure. The honeycomb structure according to any one of claims 1 to 4, wherein the X-ray intensity of the P (101) plane of the P is higher than the X-ray intensity of the P (230) plane.
In the sealing material crystal in the second cross section, when the X-ray intensity of the P (230) plane is I P230 and the X-ray intensity of the P (101) is I P101 , I P101 / I P230 The honeycomb structure according to claim 5, wherein the value is 1.8 or more and 2.5 or less.
In the encapsulant crystal in the second cross section, when the X-ray intensity of the P (002) plane is I P002 and the X-ray intensity of the P (230) plane is I P230 , I P002 / (I P002 The honeycomb structure according to claim 5 or 6, wherein a value of + IP230 is 0.12 or more and 0.18 or less.
In the encapsulant crystal in the second cross section, when the X-ray intensity of the P (101) plane is I P101 and the X-ray intensity of the P (002) plane is I P002 , I P002 / I P101 The honeycomb structure according to any one of claims 5 to 7, wherein the value of is not less than 0.05 and not more than 0.30.
On the outlet side, I 232 / (I when the X-ray intensity of the (232) plane of the partition crystal in the first cross section is I 232 and the X-ray intensity of the (230) plane is I 230. 232 + I 230 ) and the X-ray intensity of the P (232) plane of the sealing material crystal in the second cross section as I P232 and the X-ray intensity of the P (230) plane as I P230 The honeycomb structure according to any one of claims 5 to 8, wherein a value of I P232 / (I P232 + I P230 ) is different.
A gas treatment apparatus comprising the honeycomb structure according to any one of claims 1 to 9 in a case to which an exhaust gas introduction pipe is connected.