JPH09327627A - Catalyst and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst exhibiting an excellent performance in heat exchanging efficiency, life and other characteristics. SOLUTION: A honeycomb structured body 1 made of ceramics having a large number of narrow holes oriented in a same direction is penetrated by a tubular metal 2 in a direction in which the narrow holes extend so that the honeycomb structured body 1 and the tubular metal are integrated, and the ceramic honeycomb structured body 1 having a small heat capacity is used as a catalyst carrier and the tubular metal 2 is used as a side which gets in close contact with a wall face of a heat exchanger in order to enhance thermal conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst member mainly used for catalytic combustion, exhaust gas purification, deodorization and the like.

[0002]

2. Description of the Related Art Generally, catalyst members for these applications include
On a carrier substrate such as a honeycomb structure made of ceramics or metal, by a method such as a dip method or a spray method,
What formed the catalyst layer containing the inorganic oxide carrying the catalytically active metal is used. In most cases, the catalyst member using the ceramic honeycomb structure is fixed to the catalytic reactor by using a supporting member such as a seal member made of an inorganic layered compound or a spring, and a spring.

[0003]

However, in the case of catalytic combustion in a heat generating device or the like, since the support member of the catalyst member acts as a heat insulating layer, the efficiency of transferring combustion heat to the heat utilization portion, that is, heat exchange. It was a cause of lowering the efficiency.

In addition, in order to improve heat exchange efficiency,
A means for setting the excess air ratio (ratio of the supply air flow rate to the fuel and the stoichiometric air flow rate) to 1.0 to 1.5 and reducing the flow velocity as much as possible is used.
Combustion heat is generated on the upstream side of the catalyst member with respect to the fuel supply direction. However, when a ceramic honeycomb structure is used, the heat transfer coefficient is low due to the material itself of the honeycomb structure, and the catalyst temperature locally rises, causing deterioration of the catalyst and catalyst carrier. Therefore, it is necessary to positively dissipate heat and cool the catalyst member. On the other hand, when using a metal honeycomb structure,
In addition to high mechanical strength, it can be brought into relatively close contact with the combustion equipment, resulting in high heat transfer efficiency, which reduces the temperature difference within the catalyst member,
The thermal deterioration of the catalyst layer can be suppressed. However, since the metal plate that constitutes the honeycomb structure and the catalyst layer that is generally made of a porous inorganic oxide have low adhesion, the catalyst layer is easily separated from the metal plate, and a thick catalyst layer is formed. It had the drawback of being difficult.

In order to uniformly form a catalyst layer on the surface of a carrier substrate by means of a dipping method, a spray method, etc.,
It is necessary to prevent dripping during these processings, and the amount to be attached at one time is limited. Therefore, the same process has to be repeated a plurality of times, which causes a high cost.

Further, as the performance of the catalyst member, in these applications, it is desired that the temperature of the catalyst member rises to the catalyst activation temperature as short as possible. But,
When an extruded body such as cordierite or a honeycomb structure made of metal is used as the carrier substrate, the heat capacity of the carrier substrate itself is large, and thus it takes a long time to raise the temperature. On the other hand, a carrier substrate composed of inorganic fibers such as silica-alumina fibers has a small heat capacity, but has a weak mechanical strength, so that it is difficult to process it into an arbitrary shape. An object of the present invention is to provide a catalyst member having excellent properties such as heat exchange efficiency and life.

[0007]

A catalyst member of the present invention uses a ceramic honeycomb structure as a catalyst carrier substrate,
By forming the side surface which is in close contact with the wall surface of the heat exchanger with a cylindrical metal base material, heat conduction with the catalyst member itself or the combustion device is improved. According to the present invention, by punching a ceramic honeycomb structure with a cylindrical metal base material, the honeycomb structure and the metal base material can be easily integrated with good adhesion. The formation of the catalyst layer on the honeycomb structure can be carried out either before or after the integration with the metal base material to obtain a catalyst member having excellent characteristics.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A catalyst member of the present invention comprises a ceramic honeycomb structure having a large number of pores penetrating in the axial direction, a catalyst layer covering the surface of the honeycomb structure, and an axial direction. It is provided with a cylindrical metal base material that surrounds the outer peripheral side surface of the honeycomb structure. By adhering and fixing the cylindrical metal base material to the outer peripheral side surface of the ceramic honeycomb structure, the dimensional accuracy of the honeycomb structure can be improved and the metal base material acts as a heat conductor. You can That is, by bringing the metal base material into close contact with the wall surface of the heat exchanger, the heat generated in the catalyst member due to combustion can be quickly transferred to the outside of the catalyst member. Further, since it becomes easy to transfer heat to the downstream side of the catalyst member, the temperature gradient in the gas flow direction of the catalyst member can be eased.

Further, it is preferable that the honeycomb structure is composed of a plurality of pieces which are aligned in the axial direction and are integrated in parallel or in series with respect to the same direction. As the carrier substrate, by using a plurality of honeycomb structures integrated in the gas flow direction in series or in parallel,
The degree of freedom in catalyst configuration is increased. Thereby, for example, when a plurality of carrier base materials are integrated and installed in the parallel direction, a large combustion area can be secured, and a higher combustion load, or, while maintaining heat exchange efficiency, or It becomes possible to cope with a gas having a larger space velocity.

Further, it is preferable that the plurality of honeycomb structures are made of two or more kinds having different aperture ratios. When a plurality of carrier base materials are used in an integrated manner, by changing the aperture ratio of the honeycomb structure arranged in series or in parallel in the gas flow direction, the gas flow direction or the direction perpendicular to the gas flow direction, respectively. The temperature gradient in the catalyst member can be reduced. For example, by increasing the aperture ratio of the upstream honeycomb structure, which is likely to reach a relatively high temperature, and lowering the aperture ratio of the downstream catalyst member, which is relatively low temperature, the temperature distribution is made uniform and the reaction rate of the catalyst is increased. Can be made uniform, and thus thermal deterioration of the catalyst can be prevented. Further, the aperture ratio of the honeycomb structure on the outer peripheral side may be relatively lower than the aperture ratio of the honeycomb structure inside. These means are the cells (pores) of the honeycomb structure.
This can be dealt with by changing the number or the thickness of the partition walls between cells.

At least one of the plurality of honeycomb structures is preferably made of metal. For example, as a catalyst carrier substrate, a metal honeycomb structure and a ceramic honeycomb structure are used together, a ceramic honeycomb structure is used on the upstream side of the catalyst member, and a metal honeycomb structure is used on the downstream side. As a result, the efficiency of heat transfer to the outside of the catalyst member can be increased. on the other hand,
When the amount of combustion is relatively large, a metal honeycomb structure having a high heat transfer coefficient is used on the upstream side and a ceramic honeycomb structure is used on the downstream side to suppress the temperature rise on the upstream side of the catalyst member. The combustion deterioration of the catalyst can be prevented. Also, by using a metal honeycomb structure in the center of the catalyst member that tends to reach a relatively high temperature and a ceramic honeycomb structure on the outside, thermal deterioration of the catalyst is prevented while maintaining the reaction rate of the catalyst. can do.

Further, it is preferable that the catalyst layers on the surfaces of the plurality of honeycomb structures are made of two or more kinds having different catalysts. High temperature durability, reaction rate, selectivity of reactants, etc.
Catalysts with different reaction characteristics can be arranged according to the expected temperature distribution in the gas flow direction.
As a result, different catalyst characteristics can be exhibited within the same catalyst member, and the performance of the catalyst member can be improved. Since the reaction characteristics of the catalyst with respect to these fuels greatly differ depending on the catalytically active species, the catalyst to be supported on the catalyst carrier base material is selected and used according to the type of fuel. Taking platinum group metals, which are catalytically active metals used for combustion of methane, as an example, Pd has excellent low-temperature activity, but its reaction rate at high temperatures is inferior to Pt, and unreacted substances are discharged into exhaust gas. . On the other hand, Pt is inferior to Pd in low temperature activity,
The reaction rate is high above the catalyst activation temperature. Pt and Pd
When the same is carried on the same honeycomb structure, it is alloyed by firing at a high temperature, so that the obtained catalyst member cannot obtain sufficient characteristics. On the other hand, by supporting Pt and Pd on a plurality of honeycomb structures and using them integrally, it is possible to obtain a catalyst member exhibiting excellent catalytic properties.

Further, it is preferable that the metal base material has a plurality of holes penetrating the side surface. By using a metal base material arranged on the outer peripheral side surface of the honeycomb structure having a large number of holes such as punching metal or expanded metal, the heat capacity corresponding to the metal base material of the holes is reduced,
The heating rate of the catalyst member can be increased.

Further, it is preferable that the metal base material has irregularities on its side surface. The degree of contact with the heat exchanger can be adjusted by forming corrugations on the side surface of the metal base material. For example, a relatively high temperature portion is positively brought into contact with the heat exchanger inner wall, while a relatively low temperature portion has a small contact area with the heat exchanger inner wall and a low heat transfer coefficient. By so doing, the temperature gradient in the gas flow direction in the catalyst member is relaxed, and thermal deterioration of the catalyst is prevented, and
It can be arbitrarily set to a temperature range where the catalytic activity can be exhibited.

Further, it is preferable that the honeycomb structure is provided with a metal rod inserted through the honeycomb structure in the axial direction. By inserting one or more metal rods through the ceramic honeycomb structure in the direction of extension of the pores, that is, in the gas flow direction, the temperature in the gas flow direction is excellent due to the excellent heat conduction of the metal rods. The gradient can be relaxed.

Furthermore, it is preferable that the length of the metal base material is longer than the axial length of the honeycomb structure. By making the length of the cylindrical metal base material longer than the length of the honeycomb structure, the contact area between the metal base material and the heat exchanger can be widened, and the heat exchange efficiency can be improved.

By installing a heat exchange pipe between these catalyst members and passing a heat medium such as water, the combustion heat can be used more effectively. Further, by providing an electric heater and heating the catalyst member, it is possible to quickly transfer heat to the catalyst and raise the temperature to the activation temperature of the catalyst in a short time.

The method for producing a catalyst member of the present invention is a slurry in which an inorganic oxide is dispersed in an aqueous solution in which a noble metal salt is dissolved in a ceramic honeycomb structure having a large number of pores penetrating in a specific direction, or water. A step of forming a catalyst layer containing a noble metal on the surface of the honeycomb structure by immersing in a slurry in which an inorganic oxide carrying a noble metal is dispersed, followed by drying and firing, and a honeycomb structure and a tubular metal By aligning the stretching direction of the pores of the honeycomb structure with the length direction of the metal base material and overlapping and pressing the base material in the same direction, the honeycomb structure conformed to the inner surface shape of the metal base material. It includes a step of cutting it into a tubular shape and fixing it to the inner surface of the metal base material. A cylindrical metal member is mounted on a jig as required, and after overlapping with a ceramic honeycomb structure, the both are pressed to punch the honeycomb structure with a metal base material to form a honeycomb structure. The outer peripheral side surface is made to coincide with the inner side surface of the metal base material to integrate them. Thereby, high adhesion can be obtained between the honeycomb structure and the metal members surrounding the honeycomb structure, and high heat exchange efficiency can be obtained. Further, according to this method, since the catalyst layer is not formed on the outer peripheral side surface of the metal base material, the catalyst member can be brought into closer contact with the inner wall of the heat exchanger. At this time, the remaining cut-out portion of the honeycomb structure, that is, the portion left outside the tubular metal substrate is discarded.

Another method for producing a catalyst member according to the present invention is a slurry in which an inorganic oxide is dispersed in an aqueous solution in which a precious metal salt is dissolved in a ceramic honeycomb structure having a large number of pores penetrating in a specific direction. Alternatively, a step of forming a catalyst layer containing a noble metal on the surface of the honeycomb structure by immersing in a slurry in which an inorganic oxide carrying a noble metal is dispersed in water, followed by drying and firing, and forming a catalyst layer on the surface A plurality of the honeycomb structure, the step of stacking the pores in the same direction as the pores, and the plurality of stacked honeycomb structures and the tubular metal substrate, and the direction in which the pores of the honeycomb structure are stretched. By aligning the length direction of the metal base material and overlapping and pressing in the same direction, the honeycomb structure is cut out into a cylinder shape that matches the shape of the inner side surface of the metal base material, and is fixed to the inner side surface of the metal base material. You It is intended to include the process. By supporting the catalyst on the honeycomb structure, stacking the catalyst, and cutting it out, it is possible to easily produce a catalyst member in which a plurality of honeycomb structures supporting different catalysts in the gas flow direction are integrated. Alternatively, the honeycomb structure may be impregnated with a slurry containing a noble metal, dried, punched with a metal base material, and then fired.

Further, in another method for producing a catalyst member of the present invention, a ceramic honeycomb structure having a large number of pores penetrating in a specific direction and a cylindrical metal base material By aligning the stretching direction and the length direction of the metal base material and stacking and pressing in the same direction, the honeycomb structure is cut out into a tubular shape that matches the inner surface shape of the metal base material, and A step of preparing a carrier substrate which is fixed on the side surface and where the metal substrate and the honeycomb structure are integrated, and the carrier substrate is a slurry in which an inorganic oxide is dispersed in an aqueous solution of a noble metal salt, or a noble metal in water. After being immersed in a slurry in which an inorganic oxide carrying is dispersed, dried,
It includes a step of forming a catalyst layer containing a noble metal on the surface of the carrier substrate by firing. According to this method, when using an expensive precious metal as a catalyst component,
It is possible to reduce the loss of catalyst components in the manufacturing process.

The materials of the ceramic honeycomb structure are cordierite, aluminum titanate,
Although a sintered body containing mullite as a main component or an inorganic fiber such as silica-alumina can be used, the latter is easier to cut with a metal base material and has higher workability.
The metal base material can be arbitrarily selected from those having excellent heat resistance and corrosion resistance, but ferritic stainless steel containing aluminum is preferable. The catalytically active species can be selected from platinum group metals, complex oxides, etc. according to the target gas.

According to the present invention, a catalyst member in which a honeycomb structure provided with a catalyst layer is laminated can be easily produced. Therefore, the catalyst composition or the carrier structure can be optimized for the application to improve the heat of the catalyst. It is possible to suppress deterioration and improve reaction activity. Since the honeycomb structure containing ceramic fibers as a main component has a relatively small heat capacity and a large degree of freedom in shape, it is possible to raise the temperature of the catalyst member in a shorter time by using this.

[0023]

Embodiments of the present invention will be described below in detail with reference to the drawings.

<< Embodiment 1 >> In this embodiment, 3
A ceramic honeycomb plate having penetrating pores of 50 cells / inch ² was used. This ceramic honeycomb plate is formed by alternately laminating flat and corrugated ceramic sheets having a thickness of 0.5 mm and containing silica-alumina fiber and alumina sol as main components. As shown in Figure 1, 100m in length and width
A ceramic honeycomb plate 1a having a square shape of m and a thickness of 20 mm and having holes penetrating in the thickness direction is fixed, and the ceramic honeycomb plate 1a has a thickness of 1 mm.
FeCrAl steel plate of 00 μm, diameter 10 mm, length 25
mm metal-cylindrical processed metal bases 2 are stacked, pressed in the direction of the arrow, and the ceramic honeycomb plate 1a is punched out, so that the ceramic honeycomb structure 1 and its surroundings as shown in FIGS. 2 and 3. A carrier substrate 3 composed of the metal substrate 2 integrated with the above was obtained.

On the other hand, 100 g of activated alumina powder was impregnated with a dinitrodiammineplatinum aqueous solution and dried, and then 500
2% by weight of Pt on the surface by firing at ℃ for 1 hour
A supported catalyst powder (hereinafter referred to as Pt / activated alumina powder) was obtained. 100 g of this Pt / activated alumina powder, 10 g of alumina sol (solid content 20 wt%) and water 200
g was mixed to prepare a Pt catalyst slurry. Carrier substrate 3
Of the Pt catalyst slurry, and after drying, 500
By baking at 10 ° C. for 10 minutes, P is formed on the surface of the carrier substrate 3.
A catalyst layer containing 5 mg of t was formed to obtain a catalyst member.

The catalyst member 28 thus obtained is
The catalyst was mounted on the catalytic combustion apparatus shown in FIG. 4 and a combustion test was conducted as follows. However, it was mounted so that the arrow direction in FIG. First,
The catalyst member 28 was mounted inside the combustion chamber 23. 80 cc (approximately 50 kcal) of city gas per minute from the fuel supply port 21
(Corresponding to / h) and an air mixture having an excess air ratio of 1 and 8.8 liters of air were supplied to the catalyst member 28. When the mixture gas is ignited by the igniter 22, a flame is formed on the downstream side of the catalyst member 28. Thereby, the catalyst member 28
When Pt, which is a catalytically active metal contained in the surface catalyst layer, is preheated and reaches the activation temperature, catalytic combustion is started in the combustion chamber 23. At this time, the time (temperature rising time) required for the outer wall temperature of the combustion chamber 23 to rise to 200 ° C. due to catalytic combustion from flame ignition was measured by the thermocouple 24. Water is supplied at a rate of 2 cc / min to the heat exchange pipe 25, which is spirally wound around the outer peripheral side surface of the combustion chamber 23, as shown by the white arrow in the figure, and the water at the inlet and the outlet is discharged. The heat exchange efficiency was calculated from the temperature difference. Furthermore, exhaust port 2
The gas composition exhausted from No. 6 was analyzed by gas chromatography, and the burning rate was calculated from the CO ₂ and unburned hydrocarbon concentrations. Further, the temperature on the upstream side of the catalyst member 28 is equal to the temperature of the catalyst member 2
The measurement was performed with a thermocouple 27 arranged 1 mm inside from the center of the upstream end face of No. 8.

Example 2 A ceramic honeycomb plate similar to that of Example 1 was impregnated with the same Pt catalyst slurry as that of Example 1, dried and then heat-treated at 500 ° C. for 10 minutes to form a honeycomb plate surface. A catalyst layer containing 0.6 mg of Pt was formed. Then, the same cylindrical metal substrate as in Example 1 was used to punch this ceramic honeycomb plate to form a catalyst member comprising a ceramic honeycomb structure having a catalyst layer and a metal substrate surrounding the ceramic honeycomb structure. Got
The obtained catalyst member was attached to the catalytic combustion device shown in FIG.
The same combustion test as in Example 1 was performed.

Example 3 A ceramic honeycomb plate similar to that used in Example 1 but having a different thickness (350 cells / inch ² , squares 100 mm in length and width,
10 mm thick) and a ceramic honeycomb plate (480 cells / i) having the same material and a lower aperture ratio
nch ² , a square of 100 mm in length and width, and a thickness of 10 mm) was impregnated with the same Pt catalyst slurry as in Example 1, dried, and then heat-treated at 500 ° C. for 10 minutes to form a honeycomb plate of these honeycomb plates. A catalyst layer containing about 0.6 g of Pt was formed on each surface. Subsequently, these honeycomb plates are stacked and punched out in the same manner using the same cylindrical metal substrate 6 as in Example 1, so that as shown in FIG. 5, both ceramic honeycombs having the same catalyst layer are provided. A catalyst member was obtained by integrating the structure 4 and the ceramic honeycomb structure 5 having a lower aperture ratio with the metal substrate 6 surrounding the structure. The obtained catalyst member was mounted on the catalytic combustion apparatus shown in FIG. 4 so that the honeycomb structure 4 having a high aperture ratio was upstream with respect to the fuel supply direction, and the same combustion test as in Example 1 was conducted. .

Example 4 100 g of Pt / activated alumina powder similar to that of Example 1, alumina sol (solid content 20 wt.
%) And 150 g of water to prepare a Pt catalyst slurry. A ceramic honeycomb plate similar to that used in Example 3 (350 cells / inch ² , square with 100 mm in length and width, 10 mm in thickness) was impregnated with the Pt catalyst slurry described above, and dried. , 500
By performing heat treatment at 10 ° C. for 10 minutes, a catalyst layer containing 0.3 g of Pt was formed on the surface of the honeycomb plate. In addition, Example 1
100 g of activated alumina powder similar to that used in 1. was impregnated in an aqueous dinitrodiamminepalladium solution, dried, and then baked at 500 ° C. for 1 hour, so that 2% by weight of Pd was supported on the activated alumina powder. Hereinafter, this powder is referred to as Pd / activated alumina powder. 100g of this Pd / activated alumina powder, alumina sol (solid content 20wt%)
10 g and 150 g of water were mixed to prepare a Pd catalyst slurry. A ceramic honeycomb plate similar to the above is impregnated with the Pd catalyst slurry, dried, and then dried.
By performing heat treatment at 10 ° C. for 10 minutes, a catalyst layer containing 0.3 g of Pd was formed on the surface of the honeycomb plate.

After stacking these honeycomb plates in the thickness direction and punching them using the same metal base material 9 as in Example 1, as shown in FIG. 6, a catalyst layer containing Pt was provided. A catalyst member was obtained by integrating the ceramic honeycomb structure 7 and the ceramic honeycomb structure 8 including the catalyst layer containing Pd, and the metal base material 9 surrounding the ceramic honeycomb structure 8. The obtained catalyst member was mounted in the catalytic combustion apparatus of FIG. 3 so that the honeycomb structure 7 provided with the catalyst layer containing Pt was upstream in the fuel supply direction, and the same combustion test as in Example 1 was performed. I went.

<Embodiment 5> A cylindrical metal base 12 similar to that used in Embodiment 1 is provided with an outer diameter of metal base 12 inside.
A cylindrical metal honeycomb structure 10 having a thickness of 10 mm which coincides with the inner circumference of was fixed. This metallic honeycomb structure 1
0 is made of FeCrAl steel, the partition wall thickness is 50 μm,
It has a through hole of 400 cells / inch ^{2 in} the thickness direction.
Using the metal base material 12 integrated with the metal honeycomb structure 10, a ceramic honeycomb plate (thickness 10 mm) similar to that used in Example 4 is punched out in the same manner as shown in FIG. Metal honeycomb structure 1
No. 0, a ceramic honeycomb structure 11 and a metal substrate 12 fixed around these were obtained. This carrier substrate was impregnated with the same Pt catalyst slurry as in Example 1, dried and then baked at 500 ° C. for 10 minutes to form a catalyst layer containing 5 mg of Pt on the surface, as shown in FIG. A catalyst member was obtained. The obtained catalyst member was mounted on the catalytic combustion apparatus shown in FIG. 4 with the metal honeycomb structure 10 upstream with respect to the fuel supply direction, and the same combustion test as in Example 1 was performed.

Example 6 A ceramic honeycomb plate (thickness: 10 mm) similar to that used in Example 4 was impregnated with the same Pt catalyst slurry as in Example 1, dried and then dried at 500 ° C. for 10 minutes. By performing heat treatment for minutes, a catalyst layer containing 0.6 g of Pt was formed on the surface of the honeycomb plate. Subsequently, a catalyst member was prepared by similarly punching out a ceramic honeycomb plate provided with the above-mentioned catalyst layer, using the same combination of the metal base material and the metal honeycomb structure as that manufactured in Example 5. Got The obtained catalyst member was attached to the catalytic combustion apparatus shown in FIG. 4 so that the metal honeycomb structure was on the downstream side in the fuel supply direction, and the same combustion test as in Example 1 was conducted.

Example 7 A ceramic honeycomb plate (thickness 20 mm) similar to that of Example 1 was impregnated with the same Pt catalyst slurry as that of Example 1, dried and then heat treated at 500 ° C. for 10 minutes. Thus, a catalyst layer containing 0.6 g of Pt was formed on the surface of the honeycomb plate. On the other hand, the thickness is 100 μm
The diameter of the surface formed by punching is 2
A FeCrAl steel thin plate having 81 mm circular holes / m ² was processed into a cylindrical shape having a length of 25 mm and a diameter of 10 mm to obtain a metal substrate. Using this metal base material, a ceramic honeycomb plate having a catalyst layer on the surface and a ceramic honeycomb structure having a catalyst layer on its surface are integrated by punching out a ceramic honeycomb plate having the catalyst layer as in Example 1. A catalyst member composed of a metal base material was obtained. The obtained catalyst was mounted on the catalytic combustion apparatus shown in FIG. 4, and the same combustion test as in Example 1 was conducted.

Example 8 A ceramic honeycomb plate (thickness 20 mm) similar to that used in Example 1 was impregnated with the same Pt catalyst slurry as in Example 1, dried and then dried at 500 ° C. for 10 hours. By performing heat treatment for minutes, a catalyst layer containing 0.6 g of Pt was formed. On the other hand, thickness 100μ
After processing the FeCrAl steel thin plate of m into a corrugated shape, a substantially cylindrical metal substrate 14 having a length of 25 mm and a maximum outer diameter of 10 mm was prepared as shown in FIG. By punching out a ceramic honeycomb plate provided with a catalyst layer containing Pt using this metal base material 14, as shown in FIG. 8, the ceramic honeycomb structure 13 provided with the catalyst layer and the periphery thereof are integrated. A catalyst member composed of the metal base material 14 was obtained. The obtained catalyst was mounted on the catalytic combustion apparatus of FIG. 4, and the same combustion test as in Example 1 was conducted.

Example 9 For a ceramic honeycomb plate (thickness 20 mm) similar to that used in Example 1,
The same Pt catalyst slurry as in Example 1 was impregnated, dried, and then heat-treated at 500 ° C. for 10 minutes to form a catalyst layer containing 0.6 g of Pt on the surface of the honeycomb plate.
Subsequently, as shown in FIG. 9, using the same FeCrAl steel metal substrate 16 as that used in Example 7, this ceramic honeycomb plate was punched to obtain the ceramic honeycomb structure 15 and the metal substrate. The material 16 is integrated, and the diameter is 4 mm and the length is 25 mm in the central axis direction.
A circular through hole 17 having a diameter of 4 mm was formed by using the blade. A metal rod made of stainless steel (SUS304) having a diameter of 4 mm and a length of 20 mm was inserted into the through hole 17 to form a catalyst member. The obtained catalyst member was mounted on the catalytic combustion apparatus shown in FIG. 4, and the same combustion test as in Example 1 was conducted.

Comparative Example 1 A cylindrical ceramic honeycomb material made of cordierite having a partition wall thickness of 150 μm and a penetrating pore of 400 cells / inch ² and having a diameter of 10 mm and a length of 20 mm was used as Example 1. The same Pt catalyst slurry was impregnated, dried and then heat-treated at 500 ° C. for 10 minutes to form a catalyst layer containing 0.6 g of Pt on the honeycomb material surface to form a catalyst member. A seal member made of a layered inorganic compound was attached to the outer wall of the obtained catalyst member, mounted on the catalytic combustion apparatus shown in FIG. 4, and the same combustion test as in Example 1 was conducted.

Comparative Example 2 A cylindrical metal honeycomb material having a diameter of 10 mm and a length of 20 mm made of FeCrAl steel and having a partition wall thickness of 50 μm and penetrating pores of 400 cells / inch ² was used. After impregnating with the same Pt catalyst slurry as above and drying, the process of heat treatment at 500 ° C. for 10 minutes is repeated three times, whereby Pt is added to the surface of the honeycomb material by 5 times.
A catalyst layer containing mg was formed and used as a catalyst member. A seal member made of a layered inorganic compound was attached to the outer wall of the obtained catalyst member and mounted on the catalyst combustion apparatus shown in FIG.
The same burning test was conducted.

Table 1 shows the results of combustion tests using the catalyst members of Examples 1 to 9 and Comparative Examples 1 and 2.

[0039]

[Table 1]

As shown in the results of Table 1, Examples 1 to 1
In any of the catalyst members of No. 9, the temperature rising time is shorter than that of the catalyst members of Comparative Examples 1 and 2. This is because the catalyst members of Examples 1 to 9 are composed of a ceramic honeycomb structure containing ceramic fibers as a main component and a cylindrical metal base material that covers the periphery thereof. It is considered that this is because the heat capacity is smaller than that of the catalyst member of Comparative Example 1 or 2 in which each of them is used alone as the catalyst carrier substrate. The catalyst members of Examples 5 and 6 had a volume half of which was composed of a metal honeycomb structure. Therefore, the catalyst member of Example 9 was provided with a metal rod at the center, and thus the temperature rising rate was slightly higher. Considered slow.
In the catalyst member of Example 4, since Pd, which has high activity at low temperature with respect to methane which is the main component of city gas, is used on the downstream side, the heating time can be shortened as compared with Pt alone. In addition, in the catalyst member of Example 2, the metal base material arranged on the outer periphery is in direct contact with the inner wall of the combustion chamber, and thus the catalyst member of Example 2 is used.
It takes a little longer to raise the temperature as compared with a catalyst member such as the catalyst member which is in contact with the catalyst member via the catalyst layer. In the catalyst members of Examples 7 and 8, all of the side surfaces of the metal base material facing the inside of the combustion chamber wall do not come into contact with the combustion chamber, so the temperature rise time can be shortened.

Comparing the heat exchange efficiencies, the catalyst members of Examples 2, 3, 4 and 6 and Comparative Example 2 which are in close contact with the inner wall of the combustion chamber showed high values. In particular, in the catalyst member of Example 6, since the metal honeycomb structure provided on the downstream side, which is the high temperature side, has a high heat transfer coefficient, heat is directly exchanged with the inner wall of the combustion chamber, and high heat exchange efficiency is obtained. It is thought that it was done.

Comparing the burning rates, the catalytic members of Examples 1 to 9 showed higher values than the catalytic members of Comparative Examples 1 and 2. It is considered that the reason why the catalyst members of Examples 3, 7 and 8 show high values is that the temperature of the catalyst layer is appropriately increased. On the other hand, in the catalyst member of Comparative Example 1, the temperature exceeded 1000 ° C., and it was considered that the combustion characteristics deteriorated because the gas phase combustion occurred simultaneously.
Further, in the catalyst member of Comparative Example 1, the generation of CO was 2000
It was observed at about ppm. It is considered that the catalyst member of Comparative Example 2 had a lower upstream temperature than the catalyst members of the respective Examples, and therefore the heat transfer to the downstream side was slow and the burning rate was slightly low.

In the catalyst member of Comparative Example 1, cracks were observed in the honeycomb structure after combustion, and the catalyst was significantly whitened and deteriorated. It is considered that this is because the honeycomb structure made of ceramics is in direct contact with the inner wall of the combustion chamber, which hinders heat radiation and locally raises the temperature. Further, although the catalyst member of Example 9 has slightly lower combustion characteristics than the catalyst members of Examples 1 to 8, since the catalyst temperature is lowered, the catalyst member burns for a long time even if the combustion is performed at a higher load. The characteristic can be maintained.

Example 10 Similar to Example 1, a ceramic honeycomb plate having perforated holes of 350 cells / inch ² in the thickness direction (100 mm square in length and width, 20 mm in thickness) Was impregnated with the same Pt catalyst slurry as in Example 1, dried, and then heat-treated at 500 ° C. for 10 minutes to obtain 0.6 Pt on the honeycomb plate surface.
A catalyst layer containing g was formed. In addition, a metal thin plate (FeCrAl steel) having a thickness of 100 μm has a cross section of 100 mm in length and 1 in width.
A metal substrate 19 was obtained by processing it into a tubular shape having a length of 25 mm and a square of 00 mm. The metal base material 19 is arranged in seven rows in each of the vertical and horizontal directions, and the outer circumference is 100 μm thick.
Made of FeCrAl steel plate, the cross section is 700mm long and 70mm wide.
A cylindrical metal substrate 20 having a length of 25 mm and a square of 0 mm
Fixed by. The metal base material 19 and the metal base material 20 thus integrated are fixed to a press, superposed on the above-mentioned Pt-supported ceramic honeycomb plate, and then pressed to punch the honeycomb plate, as shown in FIG. A catalyst member in which the ceramic honeycomb structure 18 and the metal base materials 19 and 20 are integrated is obtained.

The obtained catalyst member 31 was mounted on the catalytic combustion apparatus shown in FIG. 11 and a combustion test was conducted. Fuel supply port 3
From No. 2, a premixed mixture of city gas and air having a combustion amount of 3000 kcal / h and an excess air ratio of 1.2 was supplied to the combustion chamber 30. The supplied air-fuel mixture is ignited by the igniter 34 and starts burning at the flame port 35. This heat causes the temperature of the catalyst member 31 to rise, and when it reaches the activation temperature,
The catalyst member 31 starts catalytic combustion. During this time, a plurality of heat exchange pipes 36 arranged on the side wall 33 of the combustion chamber are connected in series by a hose (not shown), and water is added at 300 cc / min.
And the heat exchange efficiency was determined from the temperature difference between the inlet and the outlet.

Comparative Example 3 A honeycomb material obtained by processing a ceramic honeycomb plate (thickness 20 mm) similar to that of Example 1 into a square having a length of 69 mm and a width of 69 mm was used.
After impregnating with the same Pt catalyst slurry and drying, 5
By performing heat treatment at 00 ° C. for 1 hour, a catalyst layer containing 0.6 g of Pt was formed on the surface of the honeycomb material to obtain a catalyst member. The above-mentioned catalyst member was fixed to a catalyst combustion apparatus similar to that shown in FIG. 2 with a sealing member containing vermiculite as a main component and having a thickness of 0.5 mm, and the same combustion test as in Example 10 was conducted.

The results of Example 10 and Comparative Example 3 are shown in Table 2.

[0048]

[Table 2]

As shown in Table 2, the catalyst member of Example 10 has a shorter heating time and higher heat exchange efficiency than the catalyst member of Comparative Example 3. It is considered that this is because the catalyst member of Comparative Example 3 uses the seal member to fix the catalyst member to the combustor, so that the heat transfer from the catalyst member to the heat exchange pipe is delayed. On the other hand, in the catalyst member of Example 10, the metal base materials 1 of a plurality of catalyst members were used.
It is considered that heat is efficiently conducted from 9 to the inner wall of the combustor via the metal base material 20 on the outer periphery. Further, as a result of measuring the temperature of the central portion of the upstream end surface of the catalyst member of Comparative Example 3 with a radiation thermometer, the temperature increased to 1000 ° C. or higher, whereas the same measurement was performed with the catalyst member of Example 10, 850
° C. From this, in the case of a comparatively large combustion load, the temperature of the catalyst can be made as low as possible by using the catalyst member having the structure of the tenth embodiment. As a result, the catalyst deterioration can be suppressed, the temperature rising time can be shortened, and the heat exchange efficiency can be further improved. In addition, in the catalyst member of Example 10, Example 1 and Example 3
The means used for ~ 9 can be combined.

In each of the above examples, the length of the metal base material in the gas flow direction was made longer than the length of the honeycomb structure in the same direction. Thereby, as compared with the case where these lengths are equal, workability in integrating the honeycomb structure and the metal base material is excellent, and the heat exchange efficiency is 2 to 3%.
improves. Further, in the embodiment, the shape of the catalyst member is cylindrical or quadrangular prism, but other triangular prism or elliptic cylinder can be selected. In addition, in Example 3,
Two types of honeycomb structures supporting Pt and Pd respectively were used in combination, but the number of honeycomb structures to be combined is not limited to this, and the catalyst species used are platinum group metals, inorganic oxides, etc., depending on the target fuel. It can be arbitrarily selected. Furthermore, in this embodiment, the honeycomb structure containing ceramic fibers as a main component is used, but by increasing the strength of the metal base material on the outer periphery, it can be applied to an extrusion molded body such as cordierite. When a cordierite honeycomb structure is used, the wall thickness of the partition walls between cells decreases the heat capacity.
It is preferably μm or less, and can be selected in consideration of mechanical strength.

[0051]

According to the present invention, a catalyst member having high reliability and high heat utilization efficiency is obtained by integrally using a metal base material around a ceramic honeycomb structure which is a base material of a catalyst carrier. Can be provided.

[Brief description of drawings]

FIG. 1 is a perspective view showing a manufacturing process of a catalyst member according to an embodiment of the present invention.

FIG. 2 is a perspective view of a carrier base material of the catalyst member of the example.

FIG. 3 is a view showing the carrier substrate, (a) is a top view,
(B) is a longitudinal sectional view.

FIG. 4 is a schematic vertical cross-sectional view of a catalytic combustion device used in a combustion test of catalytic members of Examples 1 to 9 of the present invention and Comparative Examples 1 and 2.

FIG. 5 is a vertical sectional view of a catalyst member according to a third embodiment of the present invention.

FIG. 6 is a vertical sectional view of a catalyst member according to the fourth embodiment.

FIG. 7 is a vertical sectional view of a catalyst member according to the fifth embodiment.

FIG. 8 is a perspective view of a catalyst member according to the eighth embodiment.

FIG. 9 is a perspective view of a catalyst member according to the ninth embodiment.

FIG. 10 is a perspective view in which a part of the catalyst member of Example 10 is cut away.

FIG. 11 is a schematic cross-sectional view of a catalytic combustion device used for a combustion test of catalyst members of Example 10 and Comparative Example 3 of the present invention, (a) is a vertical cross-sectional view, and (b) is a horizontal cross-sectional view. is there.

[Description of Reference Signs] 1 honeycomb structure made of ceramics 1a honeycomb plate made of ceramics 2 metal substrate 3 carrier substrate 4 honeycomb structure made of ceramics 5 honeycomb structure made of ceramics 6 metal substrate 7 honeycomb structure made of ceramics 8 honeycomb made of ceramics Structure 9 Metal Base Material 10 Metal Honeycomb Structure 11 Ceramic Honeycomb Structure 12 Metal Base Material 13 Ceramic Honeycomb Structure 14 Metal Base Material 15 Ceramic Honeycomb Structure 16 Metal Base Material 17 Through Hole 18 Ceramic Honeycomb Structure Body 19 Metal base material 20 Metal base material 21 Fuel supply port 22 Igniter 23 Combustion chamber 24 Thermocouple 25 Heat exchange pipe 26 Exhaust port 27 Thermocouple 28 Catalyst member 30 Combustion chamber 31 Catalytic member 32 Fuel supply port 33 Combustion chamber side wall 34 Igniter 35 flame Mouth 36 Heat exchange pipe

Claims (12)

[Claims] 1. A honeycomb structure made of ceramics having a large number of pores penetrating in the axial direction, a catalyst layer covering the surface of the honeycomb structure, and an outer peripheral side surface of the honeycomb structure in the axial direction. A catalyst member comprising a cylindrical metal base material surrounding the. 2. The catalyst member according to claim 1, wherein the honeycomb structure is composed of a plurality of members which are aligned in the axial direction and are integrated in parallel or in series with respect to the same direction. 3. The catalyst member according to claim 2, wherein the plurality of honeycomb structures are made of two or more kinds having different aperture ratios. 4. The catalyst member according to claim 2, wherein at least one of the plurality of honeycomb structures is made of metal. 5. The catalyst member according to claim 2, 3 or 4, wherein the catalyst layers formed on the surfaces of the plurality of honeycomb structures are made of two or more kinds of different catalysts. 6. The catalyst member according to claim 1, wherein the metal base material has a plurality of holes penetrating a side surface thereof. 7. The catalyst member according to claim 1, wherein the metal base material has unevenness on a side surface. 8. The catalyst member according to claim 1, further comprising a metal rod inserted through the honeycomb structure in the axial direction. 9. The catalyst member according to claim 1, wherein the length of the metal substrate is longer than the axial length of the honeycomb structure. 10. A ceramic honeycomb structure having a large number of pores penetrating in a specific direction, a slurry in which an inorganic oxide is dispersed in an aqueous solution of a noble metal salt, or an inorganic oxide in which a noble metal is supported on water. After immersing in a slurry in which is dispersed, by drying and firing, a step of forming a catalyst layer containing a noble metal on the surface of the honeycomb structure, the honeycomb structure and a tubular metal substrate, the honeycomb The honeycomb structure has a cylindrical shape that matches the inner surface shape of the metal base material by aligning the stretching direction of the pores of the structure and the length direction of the metal base material, and stacking and pressing in the same direction. A method of manufacturing a catalyst member, which comprises the steps of cutting out the metal substrate and fixing it to the inner surface of the metal substrate. 11. A ceramic honeycomb structure having a large number of pores penetrating in a specific direction, a slurry in which an inorganic oxide is dispersed in an aqueous solution of a noble metal salt, or an inorganic oxide in which noble metal is supported on water. After being dipped in a slurry in which is dispersed, drying and firing, a step of forming a catalyst layer containing a noble metal on the surface of the honeycomb structure, and a plurality of the honeycomb structure having a catalyst layer formed on the surface The step of stacking the pores by aligning the stretching directions of the pores, and the plurality of stacked honeycomb structures and a tubular metal substrate, the stretching direction of the pores of the honeycomb structure and the metal substrate By overlapping and pressing in the same direction in the same length direction, while cutting the honeycomb structure into a tubular shape that matches the inner surface shape of the metal substrate,
A method for manufacturing a catalyst member, comprising the step of fixing the inner surface of the metal base material. 12. A ceramic honeycomb structure having a large number of pores penetrating in a specific direction and a tubular metal base are provided in the direction of extension of the pores of the honeycomb structure and the lengthwise direction of the metal base. By overlapping and pressurizing in the same direction, the honeycomb structure is cut out into a tubular shape that matches the shape of the inner surface of the metal base material, and the metal is fixed to the inner surface of the metal base material. A step of producing a carrier base material in which a base material and the honeycomb structure are integrated, and the carrier base material is a slurry in which an inorganic oxide is dispersed in an aqueous solution of a noble metal salt, or an inorganic material carrying a noble metal in water. A method for producing a catalyst member, comprising a step of forming a catalyst layer containing a noble metal on the surface of the carrier substrate by immersing in a slurry in which an oxide is dispersed, followed by drying and firing.