JP2011125852A - Honeycomb structure and exhaust gas cleaning apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a honeycomb structure with superior cleaning performance of NOx, and an exhaust gas cleaning apparatus. <P>SOLUTION: The honeycomb structure 10 includes a honeycomb unit 11 which includes phosphate-based zeolite and an inorganic binder, and in which many through-holes 11a are separated by partitions 11b and juxtaposed in the longitudinal direction. The honeycomb unit 11 has macro pores of an average pore diameter of 0.1-0.3 μm, and a porosity of 30-40%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a honeycomb structure and an exhaust gas purification device.

  2. Description of the Related Art Conventionally, an SCR (Selective Catalytic Reduction) system that uses ammonia to reduce NOx to nitrogen and water is known as one of systems for purifying automobile exhaust gas.

  In addition, zeolite is known as a material that adsorbs ammonia in the SCR system.

  Patent Document 1 discloses a honeycomb structure in which a honeycomb unit includes zeolite, inorganic fibers and / or whiskers, and an inorganic binder.

WO 06/137149 Pamphlet

  There is a demand for NOx purification performance higher than that of the honeycomb structure of Patent Document 1.

  An object of the present invention is to provide a honeycomb structure and an exhaust gas purification device that are excellent in NOx purification performance in view of the problems of the above-described conventional technology.

  The honeycomb structure of the present invention includes a honeycomb unit including a phosphate-based zeolite and an inorganic binder, and a plurality of through holes arranged in parallel in the longitudinal direction with a partition wall therebetween. The average pore diameter is 0.1 μm or more and 0.3 μm or less, and the porosity is 30% or more and 40% or less.

  The phosphate zeolite is preferably at least one selected from the group consisting of SAPO, MeAPO, and MeAPSO.

  The SAPO is preferably one or more selected from the group consisting of SAPO-5, SAPO-11, and SAPO-34.

  The phosphate-based zeolite preferably includes zeolite ion-exchanged with Cu and / or Fe.

  The inorganic binder is preferably a solid content contained in one or more selected from the group consisting of alumina sol, silica sol, titania sol, water glass, sepiolite, attapulgite and boehmite.

  The honeycomb unit preferably further includes inorganic fibers and / or scaly substances.

  The inorganic fiber is at least one selected from the group consisting of alumina fiber, silica fiber, silicon carbide fiber, silica alumina fiber, glass fiber, potassium titanate fiber and aluminum borate fiber, and the scaly substance is scaly It is desirable that it is at least one selected from the group consisting of glass, scaly muscovite, scaly alumina, scaly silica, and scaly zinc oxide.

  The honeycomb structure of the present invention preferably includes a plurality of the honeycomb units.

  The exhaust gas purification apparatus of the present invention has the honeycomb structure of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the honeycomb structure and exhaust gas purification apparatus which are excellent in the purification performance of NOx can be provided.

It is a perspective view which shows an example of the honeycomb structure of this invention. It is sectional drawing which shows an example of the exhaust gas purification apparatus of this invention. It is a perspective view which shows the other example of the honeycomb structure of this invention. Fig. 4 is a perspective view showing a honeycomb unit constituting the honeycomb structure of Fig. 3.

  Next, the form for implementing this invention is demonstrated with drawing.

  FIG. 1 shows an example of the honeycomb structure of the present invention. The honeycomb structure 10 includes a phosphate-based zeolite as inorganic particles and an inorganic binder, and an outer peripheral surface of a single honeycomb unit 11 in which a plurality of through holes 11a are arranged in parallel in the longitudinal direction with a partition wall 11b interposed therebetween. An outer peripheral coat layer 12 is formed on the outer periphery.

  The average pore diameter of the macropores in the honeycomb unit 11 is 0.1 to 0.3 μm. When the average pore diameter of the macropores is less than 0.1 μm, the exhaust gas does not easily penetrate into the partition walls 11b, so that the phosphate zeolite is not effectively used for the purification of NOx. On the other hand, if the average pore diameter of the macropores exceeds 0.3 μm, the number of pores in the honeycomb unit 11 is small, so that the exhaust gas hardly penetrates into the partition walls 11b, and the phosphate-based zeolite is used for purification of NOx. It will not be used effectively.

  At this time, the pore size distribution of the honeycomb unit 11 includes a peak of micropores derived from phosphoric acid-based zeolite and a peak of macropores inside the partition walls 11b.

  The porosity of the honeycomb unit 11 is 30 to 40%. If the porosity of the honeycomb unit 11 is less than 30%, the exhaust gas does not easily penetrate into the partition walls 11b, so that the phosphate-based zeolite is not effectively used for purifying NOx. On the other hand, when the porosity of the honeycomb unit 11 exceeds 40%, the content of phosphate-based zeolite in the honeycomb unit 11 decreases, and the NOx purification rate decreases.

  The average pore diameter and porosity of the honeycomb unit 11 can be measured using a mercury intrusion method.

  Examples of phosphate zeolite include SAPO such as SAPO-5, SAPO-11, and SAPO-34; MeAPO; MeAPSO and the like.

  The phosphate-based zeolite preferably includes a phosphate-based zeolite ion-exchanged with Cu and / or Fe in consideration of NOx purification ability. The phosphate-based zeolite may further include a phosphate-based zeolite that has not been ion-exchanged and a phosphate-based zeolite that has been ion-exchanged with a metal other than the above.

  The phosphate zeolite ion-exchanged with Cu and / or Fe preferably has an ion exchange amount of 1.0 to 5.0% by mass. When the ion exchange amount of the phosphate zeolite is less than 1.0% by mass, the purification performance of NOx may be insufficient. On the other hand, when the ion exchange amount of the phosphate-based zeolite exceeds 5.0% by mass, the metal to be ion-exchanged may exist as an oxide and may not be ion-exchanged.

  The average particle size of the primary particles or secondary particles of the phosphate zeolite is preferably 0.5 to 10 μm, and more preferably 1 to 5 μm. When the average particle size of the primary particles or secondary particles of the phosphate zeolite is less than 0.5 μm, the exhaust gas hardly penetrates into the partition wall 11b, and the phosphate zeolite is effective for purifying NOx. May not be used. On the other hand, if the average particle size of the primary particles or secondary particles of the phosphate-based zeolite exceeds 10 μm, the number of pores in the honeycomb unit 11 decreases, so that the exhaust gas hardly penetrates into the partition walls 11b. In some cases, acid-based zeolites are not effectively used for NOx purification.

  The honeycomb unit 11 may further include zeolite other than phosphate zeolite such as β-type zeolite and ZSM-5-type zeolite.

  The honeycomb unit 11 preferably has a zeolite content per apparent volume of 230 to 360 g / L. If the zeolite content per apparent volume is less than 230 g / L, the apparent volume of the honeycomb unit 11 may have to be increased in order to improve the NOx purification rate. On the other hand, if the zeolite content per apparent volume exceeds 360 g / L, the strength of the honeycomb unit 11 may be insufficient or the aperture ratio of the honeycomb unit 11 may be reduced.

  The inorganic binder contained in the honeycomb unit 11 is not particularly limited, and examples thereof include solids contained in alumina sol, silica sol, titania sol, water glass, sepiolite, attapulgite, boehmite and the like, and two or more kinds may be used in combination.

  The content of the inorganic binder in the honeycomb unit 11 is preferably 5 to 30% by mass, and more preferably 10 to 20% by mass. When the content of the inorganic binder is less than 5% by mass, the strength of the honeycomb unit 11 may be reduced. On the other hand, when the content of the inorganic binder exceeds 30% by mass, extrusion of the honeycomb unit 11 may be difficult.

  In order to improve the strength, the honeycomb unit 11 preferably further includes inorganic fibers and / or scaly substances.

  The inorganic fiber contained in the honeycomb unit 11 is not particularly limited as long as the strength of the honeycomb unit 11 can be improved, but alumina fiber, silica fiber, silicon carbide fiber, silica alumina fiber, glass fiber, titanic acid A potassium fiber, an aluminum borate fiber, etc. are mentioned, You may use 2 or more types together.

  The aspect ratio of the inorganic fiber is preferably 2 to 1000, more preferably 5 to 800, and particularly preferably 10 to 500. When the aspect ratio of the inorganic fiber is less than 2, the effect of improving the strength of the honeycomb unit 11 may be reduced. On the other hand, when the aspect ratio of the inorganic fiber exceeds 1000, the mold is clogged when the honeycomb unit 11 is extruded, or the inorganic fiber breaks and the effect of improving the strength of the honeycomb unit 11 is small. Sometimes it becomes.

  The scaly substance contained in the honeycomb unit 11 is not particularly limited as long as the strength of the honeycomb unit 11 can be improved, but scaly glass, scaly muscovite, scaly alumina, scaly silica, scaly Zinc oxide and the like may be mentioned, and two or more kinds may be used in combination.

  The content of inorganic fibers and scaly substances in the honeycomb unit 11 is preferably 3 to 50% by mass, more preferably 3 to 30% by mass, and particularly preferably 5 to 20% by mass. When the content of the inorganic fibers and the scaly substance is less than 3% by mass, the effect of improving the strength of the honeycomb unit 11 may be reduced. On the other hand, if the content of inorganic fibers and scaly substances exceeds 50% by mass, the content of phosphate zeolite in the honeycomb unit 11 may decrease, and the NOx purification rate may decrease.

  The honeycomb unit 11 preferably has an opening ratio of a cross section perpendicular to the longitudinal direction of 50 to 75%. If the opening ratio of the cross section perpendicular to the longitudinal direction of the honeycomb unit 11 is less than 50%, the phosphate zeolite may not be effectively used for NOx purification. On the other hand, if the opening ratio of the cross section perpendicular to the longitudinal direction of the honeycomb unit 11 exceeds 75%, the strength of the honeycomb unit 11 may be insufficient.

In the honeycomb unit 11, the density of the through holes 11 a having a cross section perpendicular to the longitudinal direction is preferably 31 to 124 / cm ² . If the density of the through-holes 11a having a cross section perpendicular to the longitudinal direction of the honeycomb unit 11 is less than 31 / cm ² , the exhaust gas and the phosphate-based zeolite are difficult to come into contact with each other, and the NOx purification rate may be reduced. is there. On the other hand, if the density of the through holes 11a having a cross section perpendicular to the longitudinal direction of the honeycomb unit 11 exceeds 124 / cm ² , the pressure loss of the honeycomb structure 10 may increase.

  The thickness of the partition wall 11b of the honeycomb unit 11 is preferably 0.10 to 0.50 mm, and more preferably 0.15 to 0.35 mm. If the thickness of the partition wall 11b is less than 0.10 mm, the strength of the honeycomb unit 11 may be reduced. On the other hand, if the thickness of the partition wall 11b exceeds 0.50 mm, the exhaust gas hardly penetrates into the partition wall 11b, and the phosphate-based zeolite may not be effectively used for NOx purification.

  The outer peripheral coat layer 12 preferably has a thickness of 0.1 to 2 mm. If the thickness of the outer peripheral coat layer 12 is less than 0.1 mm, the effect of improving the strength of the honeycomb structure 10 may be insufficient. On the other hand, if the thickness of the outer peripheral coat layer 12 exceeds 2 mm, the content of phosphate-based zeolite per unit volume of the honeycomb structure 10 may decrease, and the NOx purification rate may decrease.

  The honeycomb structure 10 has a columnar shape, but is not particularly limited, and may have a prismatic shape, an elliptical column shape, or the like. Moreover, although the shape of the through-hole 11a is a quadrangular prism shape, it is not specifically limited, A triangular prism shape, a hexagonal column shape, etc. may be sufficient.

  Next, an example of the manufacturing method of the honeycomb structure 10 which is an example of the honeycomb structure of the present invention will be described. First, a raw material containing a phosphate-based zeolite and an inorganic binder, and further containing a zeolite other than phosphate-based zeolite such as inorganic fibers and / or scaly substances, β-type zeolite, ZSM-5-type zeolite, etc. Extrusion molding is performed using a paste to produce a raw cylindrical honeycomb formed body in which a plurality of through holes are arranged in parallel in the longitudinal direction with a partition wall therebetween. Thereby, even if the firing temperature is lowered, the cylindrical honeycomb unit 11 having sufficient strength can be obtained.

  The inorganic binder contained in the raw material paste is added as alumina sol, silica sol, titania sol, water glass, sepiolite, attapulgite, boehmite, etc., and two or more kinds may be used in combination.

  Moreover, you may add an organic binder, a dispersion medium, a shaping | molding adjuvant, etc. to a raw material paste suitably as needed.

  Although it does not specifically limit as an organic binder, Methylcellulose, carboxymethylcellulose, hydroxyethylcellulose, polyethyleneglycol, a phenol resin, an epoxy resin etc. are mentioned, You may use 2 or more types together. In addition, it is preferable that the addition amount of an organic binder is 1-10 mass% with respect to the total amount of zeolite other than a phosphate type zeolite, an inorganic binder, an inorganic fiber, a scale-like substance, and a phosphate type zeolite.

  Although it does not specifically limit as a dispersion medium, Alcohol, such as water, organic solvents, such as benzene, methanol, etc. are mentioned, You may use 2 or more types together.

  Although it does not specifically limit as a shaping | molding adjuvant, Ethylene glycol, dextrin, a fatty acid, fatty acid soap, a polyalcohol etc. are mentioned, You may use together 2 or more types.

  When preparing the raw material paste, it is preferable to mix and knead, and it may be mixed using a mixer, an attritor or the like, or may be kneaded using a kneader or the like.

  Next, the obtained honeycomb formed body is dried using a dryer such as a microwave dryer, a hot air dryer, a dielectric dryer, a vacuum dryer, a vacuum dryer, or a freeze dryer.

  Further, the dried honeycomb formed body is degreased. The degreasing conditions are not particularly limited and can be appropriately selected depending on the type and amount of the organic substance contained in the molded body, but it is preferably 400 ° C. for 2 hours.

  Next, by firing the degreased honeycomb formed body, the cylindrical honeycomb unit 11 is obtained. The firing temperature is preferably 600 to 1200 ° C, more preferably 600 to 1000 ° C. When the firing temperature is less than 600 ° C., the sintering does not proceed and the strength of the honeycomb unit 11 may be lowered. On the other hand, when the firing temperature exceeds 1200 ° C., sintering proceeds too much, and the reaction sites of the phosphate zeolite may decrease.

  Next, the outer periphery coating layer paste is applied to the outer peripheral surface of the columnar honeycomb unit 11.

  Although it does not specifically limit as a paste for outer periphery coating layers, The mixture of an inorganic binder and an inorganic particle, the mixture of an inorganic binder and an inorganic fiber, the mixture of an inorganic binder, an inorganic particle, and an inorganic fiber etc. are mentioned.

  Moreover, the outer periphery coat layer paste may further contain an organic binder. Although it does not specifically limit as an organic binder, Polyvinyl alcohol, methylcellulose, ethylcellulose, carboxymethylcellulose, etc. are mentioned, You may use 2 or more types together.

  Next, by drying and solidifying the honeycomb unit 11 to which the outer periphery coating layer paste has been applied, a cylindrical honeycomb structure 10 is obtained. At this time, when the outer peripheral coat layer paste contains an organic binder, it is preferably degreased. The degreasing conditions can be appropriately selected depending on the kind and amount of the organic matter, but it is preferably 20 minutes at 700 ° C.

  In addition, by immersing the honeycomb unit 11 in an aqueous solution containing Cu ions or Fe ions, the phosphate zeolite can be ion-exchanged. Moreover, you may use the raw material paste containing the phosphate type zeolite ion-exchanged with Cu and / or Fe.

  FIG. 2 shows an example of the exhaust gas purifying apparatus of the present invention. The exhaust gas purification apparatus 100 is obtained by canning the metal tube 30 in a state where the holding sealing material 20 is disposed on the outer peripheral portion of the honeycomb structure 10. The exhaust gas purification apparatus 100 is provided with injection means (not shown) such as an injection nozzle for injecting ammonia or a precursor thereof upstream of the honeycomb structure 10 with respect to the direction in which the exhaust gas flows. Thereby, ammonia is added to the exhaust gas. As a result, NOx contained in the exhaust gas is reduced on the phosphate zeolite contained in the honeycomb unit 11. At this time, in consideration of the storage stability of ammonia or its precursor, it is preferable to use urea water as the ammonia precursor. The urea water is hydrolyzed and heated by being heated in the exhaust gas.

  FIG. 3 shows another example of the honeycomb structure of the present invention. The honeycomb structure 10 ′ has a configuration in which a plurality of honeycomb units 11 (see FIG. 4) in which a plurality of through holes 11a are arranged in parallel in the longitudinal direction with a partition wall 11b therebetween are bonded via an adhesive layer 13. This is the same as the honeycomb structure 10.

The honeycomb unit 11 preferably has a cross-sectional area of a cross section perpendicular to the longitudinal direction of 5 to 50 cm ² . When the cross-sectional area of the cross section perpendicular to the longitudinal direction of the honeycomb unit 11 is less than 5 cm ² , the pressure loss of the honeycomb structure 10 ′ may increase. On the other hand, when the cross-sectional area of the cross section perpendicular to the longitudinal direction of the honeycomb unit 11 exceeds 50 cm ² , the strength against the thermal stress generated in the honeycomb unit 11 may be insufficient.

  The adhesive layer 13 preferably has a thickness of 0.5 to 2 mm. If the thickness of the adhesive layer 13 is less than 0.5 mm, the adhesive strength may be insufficient. On the other hand, when the thickness of the adhesive layer 13 exceeds 2 mm, the pressure loss of the honeycomb structure 10 ′ may increase.

  Further, the shape of the honeycomb unit 11 excluding the honeycomb unit 11 located on the outer peripheral portion of the honeycomb structure 10 ′ is a quadrangular prism shape, but is not particularly limited, and may be, for example, a hexagonal prism shape.

  Next, an example of a method for manufacturing a honeycomb structure 10 ′ which is another example of the honeycomb structure of the present invention will be described. First, in the same manner as the honeycomb structure 10, a quadrangular columnar honeycomb unit 11 is manufactured. Next, an adhesive layer paste is applied to the outer peripheral surface of the honeycomb unit 11, the honeycomb units 11 are sequentially bonded, and dried and solidified, whereby an aggregate of the honeycomb units 11 is manufactured.

  At this time, after the aggregate of the honeycomb units 11 is manufactured, it may be cut into a cylindrical shape and polished. Alternatively, a honeycomb unit 11 having a columnar shape may be manufactured by bonding the honeycomb units 11 having a cross-section formed in a fan shape or a square shape.

  Although it does not specifically limit as a paste for contact bonding layers, The mixture of an inorganic binder and an inorganic particle, the mixture of an inorganic binder and an inorganic fiber, the mixture of an inorganic binder, an inorganic particle, and an inorganic fiber etc. are mentioned.

  The adhesive layer paste may contain an organic binder. Although it does not specifically limit as an organic binder, Polyvinyl alcohol, methylcellulose, ethylcellulose, carboxymethylcellulose, etc. are mentioned, You may use 2 or more types together.

  Next, the outer peripheral coat layer paste is applied to the outer peripheral surface of the aggregate of columnar honeycomb units 11. Although the outer periphery coating layer paste is not particularly limited, it may contain the same material as the adhesive layer paste or may contain a different material. Further, the outer peripheral coat layer paste may have the same composition as the adhesive layer paste.

  Next, by drying and solidifying the aggregate of the honeycomb units 11 to which the outer peripheral coat layer paste has been applied, a cylindrical honeycomb structure 10 ′ is obtained. At this time, when an organic binder is contained in the adhesive layer paste and / or the outer peripheral coat layer paste, it is preferable to degrease. The degreasing conditions can be appropriately selected depending on the kind and amount of the organic matter, but it is preferably 20 minutes at 700 ° C.

  Note that the outer peripheral coat layer 12 may not be formed on the honeycomb structures 10 and 10 ′.

[Example 1]
First, SAPO 3100 g having an average particle diameter of 3.3 μm, 875 g boehmite, 485 g alumina fiber having an average fiber diameter of 100 μm, 380 g methylcellulose, 280 g oleic acid, ion-exchanged with 2.7% by mass with Cu And 2425 g of ion-exchanged water was mixed and kneaded to prepare a raw material paste 1.

  Next, the raw material paste 1 was extrusion-molded using an extrusion molding machine to produce a raw regular quadrangular prism-shaped honeycomb molded body. Then, the honeycomb formed body was dried at 110 ° C. for 10 minutes using a microwave dryer and a hot air dryer, and then degreased at 400 ° C. for 5 hours. Next, the honeycomb unit 11 was fired at 700 ° C. for 2 hours to form a square prism-shaped honeycomb unit 11 having a side of 34.3 mm and a length of 150 mm.

The honeycomb unit 11 had a density of through-holes 11a of 93 / cm ² , a partition wall 11b thickness of 0.23 mm, an average pore diameter of macropores of 0.20 μm, and a porosity of 35%. Here, the average pore diameter and porosity of the macropores were measured using a mercury porosimeter.

  Next, 767 g of alumina fibers having an average fiber diameter of 0.5 μm and an average fiber length of 15 μm, 2500 g of silica glass, 17 g of carboxymethylcellulose, 600 g of silica sol having a solid content of 30% by mass, 167 g of polyvinyl alcohol, 167 g of surfactant, and 17 g of alumina balloon Were mixed and kneaded to prepare a heat-resistant adhesive layer paste.

  The adhesive layer paste was applied so that the thickness of the adhesive layer was 2 mm, 16 honeycomb units 11 were adhered, the adhesive layer paste was dried and solidified at 150 ° C. for 10 minutes, and then using a diamond cutter, The honeycomb unit 11 was assembled by cutting into a cylindrical shape so that the cross section perpendicular to the longitudinal direction was substantially point-symmetric.

  Further, after the adhesive layer paste is applied to the outer peripheral surface of the aggregate of the honeycomb units 11 so that the thickness of the outer peripheral coat layer becomes 1 mm, the adhesive layer paste is used by using a microwave dryer and a hot air dryer. Was dried and solidified at 150 ° C. for 10 minutes and degreased at 400 ° C. for 2 hours to produce a cylindrical honeycomb structure 10 ′ having a diameter of 143.8 mm and a height of 150 mm.

  Next, in a state where the holding sealing material (mat made of inorganic fibers) 20 is disposed on the outer peripheral portion of the honeycomb structure 10 ′, the honeycomb structure 10 ′ is canned to the metal pipe (shell) 30 to produce an exhaust gas purification device (see FIG. 2). .

[Example 2]
SAPO 3100 g having an average particle diameter of 1.3 μm, 895 g of boehmite, 485 g of alumina fibers having an average fiber length of 100 μm, 420 g of methyl cellulose, 280 g of oleic acid, and ions ion-exchanged with Cu by 2.7% by mass The raw material paste 2 was prepared by mixing and kneading 2600 g of exchange water.

  A honeycomb structure 10 ′ and an exhaust gas purification device were manufactured in the same manner as in Example 1 except that the raw material paste 2 was used instead of the raw material paste 1.

  The honeycomb unit 11 had an average pore diameter of macropores of 0.10 μm and a porosity of 35%.

[Example 3]
SAPO 3100 g having an average particle diameter of 5.0 μm, boehmite 895 g, average fiber diameter 6 μm, average fiber length 100 μm alumina fiber 485 g, methylcellulose 350 g, oleic acid 280 g, and ions The raw material paste 3 was prepared by mixing and kneading 2250 g of exchange water.

  A honeycomb structure 10 ′ and an exhaust gas purification device were produced in the same manner as in Example 1 except that the raw material paste 3 was used instead of the raw material paste 1.

  The honeycomb unit 11 had an average pore diameter of macropores of 0.30 μm and a porosity of 35%.

[Example 4]
SAPO 3100 g having an average particle size of 3.3 μm, 895 g boehmite, 485 g alumina fiber having an average fiber length of 100 μm, 350 g of methyl cellulose, 280 g of oleic acid and ions ionic exchanged with Cu by 2.7% by mass The raw material paste 4 was produced by mixing and kneading 2250 g of exchange water.

  A honeycomb structure 10 ′ and an exhaust gas purification device were produced in the same manner as in Example 1 except that the raw material paste 4 was used instead of the raw material paste 1.

  The honeycomb unit 11 had an average pore diameter of macropores of 0.20 μm and a porosity of 30%.

[Example 5]
SAPO 3100 g having an average particle size of 3.3 μm, 895 g boehmite, 485 g of alumina fibers having an average fiber length of 100 μm, 420 g of methyl cellulose, 280 g of oleic acid and ions ion-exchanged with Cu by 2.7% by mass The raw material paste 5 was prepared by mixing and kneading 2600 g of exchange water.

  A honeycomb structure 10 ′ and an exhaust gas purification device were produced in the same manner as in Example 1 except that the raw material paste 5 was used instead of the raw material paste 1.

  The honeycomb unit 11 had an average pore diameter of macropores of 0.20 μm and a porosity of 40%.

[Comparative Example 1]
SAPO 3100 g having an average particle diameter of 1.3 μm, 895 g boehmite, 485 g alumina fiber having an average fiber length of 100 μm, 380 g methylcellulose, 280 g oleic acid and ions ion-exchanged with Cu by 2.7% by mass The raw material paste 6 was prepared by mixing and kneading 2425 g of exchange water.

  A honeycomb structure 10 ′ and an exhaust gas purification device were produced in the same manner as in Example 1 except that the raw material paste 6 was used instead of the raw material paste 1.

  The honeycomb unit 11 had an average pore diameter of macropores of 0.08 μm and a porosity of 32%.

[Comparative Example 2]
SAPO 3100 g having an average particle diameter of 5.5 μm, 895 g boehmite, 485 g alumina fiber having an average fiber length of 100 μm, 350 g of methyl cellulose, 280 g of oleic acid, and ions ion-exchanged with Cu by 2.7% by mass The raw material paste 7 was prepared by mixing and kneading 2250 g of exchange water.

  A honeycomb structure 10 ′ and an exhaust gas purification device were produced in the same manner as in Example 1 except that the raw material paste 7 was used instead of the raw material paste 1.

  The honeycomb unit 11 had an average pore diameter of macropores of 0.35 μm and a porosity of 38%.

[Comparative Example 3]
SAPO 3100 g having an average particle diameter of 3.3 μm, 895 g boehmite, 485 g alumina fiber having an average fiber length of 100 μm, 450 g of methyl cellulose, 280 g of oleic acid, and ions ion-exchanged with Cu by 2.7% by mass The raw material paste 8 was produced by mixing and kneading 2740 g of exchange water.

  A honeycomb structure 10 ′ and an exhaust gas purification device were produced in the same manner as in Example 1 except that the raw material paste 8 was used instead of the raw material paste 1.

  The honeycomb unit 11 had an average pore diameter of macropores of 0.20 μm and a porosity of 43%.

[Measurement of NOx purification rate]
From the honeycomb structure 10 ′ produced in Examples 1 to 5 and Comparative Examples 1 to 3, a part of a regular prismatic honeycomb unit 11 having a side of 34.3 mm and a length of 40 mm was cut out, and an evaluation sample and did.

Nitrogen monoxide flowing out from the sample for evaluation using a catalyst evaluation apparatus SIGU (manufactured by Horiba, Ltd.) while flowing a simulated gas of 150 ° C. at a space velocity (SV) of 35000 / hr to each sample for evaluation. NO) outflow rate is measured, and the formula (NO inflow amount−NO outflow amount) / (NO inflow amount) × 100
The NOx purification rate [%] represented by The constituent components of the simulated gas are 175 ppm of nitric oxide, 175 ppm of nitrogen dioxide, 350 ppm of ammonia, 14% by volume of oxygen, 5% by volume of carbon dioxide, 10% by volume of water, and nitrogen (balance). The measurement results are shown in Table 1.

表１より、実施例１〜５で作製したハニカム構造体１０'から切り出した評価用の試料は、ＮＯｘの浄化率が高いことがわかる。

From Table 1, it can be seen that the samples for evaluation cut out from the honeycomb structure 10 ′ produced in Examples 1 to 5 have a high NOx purification rate.

  From the above, the honeycomb unit 11 has an average pore diameter of 0.1 to 0.3 μm and a porosity of 30 to 40%. It is considered that the NOx purification performance is excellent.

  In the present embodiment, the honeycomb structure 10 ′ is shown, but it is considered that the same effect can be obtained with the honeycomb structure 10 as well.

DESCRIPTION OF SYMBOLS 10, 10 'Honeycomb structure 11 Honeycomb unit 11a Through-hole 11b Partition 12 Outer periphery coating layer 13 Adhesive layer 20 Holding sealing material 30 Metal pipe 100 Exhaust gas purification apparatus

Claims (9)

A honeycomb structure including a honeycomb unit including a phosphate-based zeolite and an inorganic binder and having a plurality of through holes arranged in parallel in a longitudinal direction with a partition wall therebetween,
In the honeycomb unit, the average pore diameter of macropores is 0.1 μm or more and 0.3 μm or less, and the porosity is 30% or more and 40% or less.   The honeycomb structure according to claim 1, wherein the phosphate-based zeolite is at least one selected from the group consisting of SAPO, MeAPO, and MeAPSO.   The honeycomb structure according to claim 2, wherein the SAPO is at least one selected from the group consisting of SAPO-5, SAPO-11, and SAPO-34.   The honeycomb structure according to any one of claims 1 to 3, wherein the phosphate-based zeolite includes zeolite ion-exchanged with Cu and / or Fe.   The said inorganic binder is solid content contained in 1 or more types selected from the group which consists of alumina sol, silica sol, titania sol, water glass, sepiolite, attapulgite, and boehmite. The honeycomb structure according to 1.   The honeycomb structure according to any one of claims 1 to 5, wherein the honeycomb unit further includes inorganic fibers and / or scaly substances. The inorganic fiber is at least one selected from the group consisting of alumina fiber, silica fiber, silicon carbide fiber, silica alumina fiber, glass fiber, potassium titanate fiber and aluminum borate fiber,
The honeycomb structure according to claim 6, wherein the scaly substance is at least one selected from the group consisting of scaly glass, scaly muscovite, scaly alumina, scaly silica, and scaly zinc oxide. body.   The honeycomb structure according to any one of claims 1 to 7, comprising a plurality of the honeycomb units.   An exhaust gas purification apparatus comprising the honeycomb structure according to any one of claims 1 to 8.

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