JP2006142260A - Structure for sheetlike catalyst carrier and method for manufacturing the structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure for a sheetlike catalyst carrier which contains a mineral fiber which keeps a fibrous state just before fired, consequently has a shape keeping effect and functions as a sintering aid and to provide a method for manufacturing the structure for the sheetlike catalyst carrier. <P>SOLUTION: This method for manufacturing the structure for the sheetlike catalyst carrier comprises a slurry preparing step S1 of mixing an inorganic filler and an inorganic binder in predetermined water to prepare slurry, a flock producing step S2 of adding a flocculant to the prepared slurry to produce flocks, a sheet manufacturing step S3 of manufacturing a sheet from flocks to obtain a sheetlike porous structure and a firing step S5 of firing the obtained sheetlike porous structure to obtain the objective structure for the sheetlike catalyst carrier. At the slurry preparing step S1, the mineral fiber, which keeps the fibrous state just before the firing temperature at the firing step S5, is melted at the firing temperature and performs a sintering action, is incorporated in the slurry together with the inorganic filler and the inorganic binder. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet-like catalyst carrier structure that includes an inorganic filler, an inorganic binder, and a flocculant and can support a predetermined catalyst, and a method for producing the same.

With the recent increase in awareness of environmental problems, purification catalysts used for purifying various exhaust gases, for example, are becoming widespread. As this purification catalyst, a sheet-shaped catalyst carrier structure in which a predetermined catalyst is supported on a sheet-shaped ceramic sheet as disclosed in Patent Document 1, for example, has been proposed. Such a structure for a sheet-like catalyst carrier is obtained by forming a sheet of a catalyst carrier mainly composed of an inorganic oxide, a heat-resistant inorganic fiber, and a noble metal that can be a catalyst by a wet papermaking method (dispersion, aggregation, papermaking, drying process). It was obtained.
JP-A-7-204517

  However, in the above conventional sheet-like catalyst carrier structure, the necessary fiber for forming into a sheet by the wet papermaking method is a heat-resistant inorganic fiber. There was a problem that the sheet did not melt even after passing through the process of holding the sheet for a long period of time and could not function as a binder. However, in the wet papermaking method, generally, an inorganic binder made of colloidal silica, alumina or the like has been added, but such a binder is dispersed in a point-like manner in the structure for the catalyst support in the production process. There was a problem of poor bonding strength. That is, since the sheet-like structure for a catalyst carrier is manufactured by wet papermaking, the amount of the inorganic binder added is reduced and the strength cannot be improved. There is also a problem that it is necessary to separately add a sintering aid for promoting sintering in the firing step.

  The present invention has been made in view of such circumstances, and is used for a sheet-like catalyst carrier having mineral fibers that can maintain a fibrous shape during firing, have a shape retention effect, and can function as a sintering aid. The object is to provide a structure and a manufacturing method thereof.

  The invention according to claim 1 comprises an inorganic filler, an inorganic binder, and an aggregating agent, and in the structure for a sheet-like catalyst carrier capable of supporting a predetermined catalyst, while maintaining the fibrous form until just before the firing temperature, It is characterized by comprising mineral fibers that melt at the firing temperature to produce a sintering action.

According to a second aspect of the present invention, in the structure for a sheet-like catalyst carrier according to the first aspect, the mineral fiber has a SiO ₂ content of 35.0 to 45.0 wt% and an Al ₂ O ₃ content of 20.0 to 30. 0.0% by weight and CaO + MgO + FeO has a composition of 15.0 to 30.0% by weight.

  The invention according to claim 3 is a slurry generation step in which an inorganic filler and an inorganic binder are mixed in a predetermined amount of water to generate a slurry, and a flocculant is added to the slurry obtained in the slurry generation step to add a floc Generating a sheet, forming a sheet to obtain a sheet-like porous structure by sheeting the floc obtained in the flock-generating process, and a sheet-like porous structure obtained in the sheet-forming process In the method for producing a sheet-like catalyst carrier structure by a wet papermaking method, wherein the slurry generating step includes the inorganic filler and the inorganic binder. The slurry is characterized in that the fiber is held until just before the firing temperature in the firing step, and mineral fibers that melt at the firing temperature and produce a sintering action are contained in the slurry.

  According to a fourth aspect of the present invention, in the method for producing a sheet-like catalyst carrier structure according to the third aspect, the flocculant added in the flock generation step is one of two high polymers, a cationic polymer and an anionic polymer. It consists of a molecular flocculant.

  According to the invention of claim 1, the sheet-like catalyst carrier structure improves the sintering action while maintaining the fiber shape until just before the firing temperature, and the mineral fiber that melts at the firing temperature and obtains the binding action Since it is contained, the mineral fiber can maintain a fibrous state at the time of firing and can function as a sintering aid and can function as a binder having a large bonding force.

According to the invention of claim 2, mineral fibers, SiO ₂ is from 35.0 to 45.0 wt%, _Al 2 _{O 3} is 20.0 to 30.0 wt%, CaO + MgO + FeO 15.0~30.0 Since it consists of a composition by weight%, the effect of claim 1 can be achieved more satisfactorily.

  According to the invention of claim 3, since the sheet-like catalyst carrier structure can be obtained by the wet papermaking method, it is sufficient to contain mineral fibers in the slurry generated during the slurry generation step. Manufacturing equipment using a papermaking method) can be used. Therefore, it is possible to avoid an increase in manufacturing cost as compared with a case where a new separate process is added.

  According to the fourth aspect of the present invention, since the flocculant added in the floc generating step is composed of two polymer flocculants, a cationic polymer and an anionic polymer, the yield can be remarkably improved.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
The sheet-like catalyst carrier structure according to the present embodiment is composed of a sheet-like structure capable of supporting a predetermined metal catalyst. As shown in FIG. 1, a slurry generation step S1, a flock generation step S2, It is manufactured by passing through the sheet forming step S3, the drying step S4, and the firing step S5. In addition, you may add the beating process which beats and unravels the organic fiber as a raw material before slurry production | generation process S1.

  In the slurry generation step S1, a predetermined amount of inorganic fiber, organic fiber, inorganic filler, inorganic binder, organic binder, catalyst powder composed of a metal oxide and a predetermined metal (for example, copper metal), pore adjuster, and mineral fiber are added. After mixing with water, the mixture is sufficiently stirred with a stirrer or the like to produce a slurry in which the contents are uniformly dispersed.

  An inorganic fiber is comprised by Al, Si, Mg, Ti, C, Zr, Fe, Cr, O etc., for example, consists of a fiber whose heat-resistant temperature is 1000 degreeC or more, and contains a whisker. Thermally stable at the firing temperature. As the organic fiber, it is preferable to use a plant-based organic fiber. By adding the organic fiber, the sheet-like structure after paper making can be made uniform, the yield can be improved, or the strength can be increased.

  Examples of the inorganic filler include oxides such as alumina, forsterite, enstatite, spinel, silica, mullite, cordierite, zircon, aluminum titanate, magnesia, titania, zirconia, and hydroxides such as aluminum hydroxide and titanium hydroxide. , Carbonates such as calcium carbonate, viscosity of talc, clay, kaolinite, etc., kneaded paints such as black, titanium yellow, and pottery, or vanadium, chromium, manganese, iron, cobalt, nickel Examples thereof include metal oxides such as copper and tungsten, and oxides of rare earth elements such as cerium, protheodymium, neodymium, and samarium.

  Examples of the inorganic binder include colloidal alumina, colloidal silica, colloidal zirconia, colloidal titania, and the like, and the contained fiber and the inorganic filler can be bound by the inorganic binder in the drying step S4 and the firing step S5. Along with the organic fiber that has disappeared in the firing step S5, a shape retention effect is achieved. The organic binder exerts a reinforcing effect on the sheet-like structure after papermaking, and can improve the tensile strength by addition to improve the workability.

  As described above, the catalyst powder is composed of a metal oxide and a predetermined metal, and should be selected according to the expected catalyst activity. That is, the predetermined metal is uniformly dispersed and deposited in the pores of the sheet-like porous structure after the paper making using the metal oxide as a catalyst carrier, and performs a desired catalytic reaction. The pore adjuster is generally used for adjusting the porosity of the nonwoven fabric, and is made of, for example, natural diatomaceous earth, carbon fiber, graphite, or the like.

  Here, in this embodiment, in the slurry generation step S1, in addition to the inorganic filler and the inorganic binder, mineral fibers are also contained in the slurry generated by mixing with a predetermined amount of water. Such a mineral fiber retains the fiber shape until immediately before the firing temperature (about 1300 to 1500 ° C.) in the firing step S5, and melts at the firing temperature to produce a sintering action. For example, sepiolite, wollastonite, It is composed of rock wool, glass wool, slag wool, etc. made of tobermorite and zonotlite.

Furthermore, mineral fibers, SiO ₂ is from 35.0 to 45.0 wt%, _Al 2 _{O 3} is 20.0 to 30.0 wt%, the fibers CaO + MgO + FeO is made of a composition of 15.0 to 30.0 wt% Is preferred. If such a mineral fiber is used, it maintains a fibrous shape up to the firing temperature, has the effect of maintaining the shape of the structure, and melts at the firing temperature to function as a sintering aid. However, since the mineral fiber has a fibrous shape, it is contained in the structure while being entangled with other raw materials (inorganic fillers, etc.), and it is melted during firing so A high sintering effect that cannot be obtained can be obtained.

  The floc generation step S2 is a step for generating flocs by adding a flocculant to the slurry obtained in the slurry generation step S1. In the present embodiment, two types of cationic polymer and anionic polymer are used. A polymer flocculant is used. By using these two polymer flocculants in combination, the yield of the manufactured sheet-like catalyst carrier structure can be significantly improved.

  The sheet forming step S3 is a step for obtaining a sheet-like porous structure by making the flock obtained in the flock generating step S2, and obtaining a sheet shape having a uniform thickness through this step. Can do. The obtained sheet-like porous structure is fired in the firing step S5 through the drying step S4, thereby forming a sheet-like catalyst carrier structure. In addition, between the drying step S4 and the firing step S5, the porosity may be controlled by pressing the sheet-like porous structure obtained in the sheet forming step S5 from the surface thereof.

  The firing step S5 is a step for firing the sheet-like porous structure obtained in the sheet forming step S5 to obtain a sheet-like catalyst structure. Specifically, as described above, about 1300 In this step, the sheet-like porous structure is sintered by raising the temperature to 1500 ° C. to obtain a sheet-like structure for a catalyst carrier having a predetermined strength (bending strength). As described above, the mineral fiber in the firing step S5 is sintered by maintaining the shape of the fiber until immediately before the firing temperature and maintaining the shape retaining effect, and by melting at the firing temperature to produce a sintering action. Acts as an aid.

  As described above, the sheet-shaped catalyst carrier structure according to this embodiment can be obtained through a series of steps. According to the present embodiment, since the sheet-like catalyst carrier structure is obtained by the wet papermaking method, it is sufficient to contain mineral fibers in the slurry generated during the slurry generation step S1, and therefore existing equipment (wet papermaking) Manufacturing equipment using the method). Therefore, it is possible to avoid an increase in manufacturing cost as compared with a case where a new separate process is added.

  Although the present embodiment has been described above, the present invention is not limited to this, and can also be applied to a sheet-like catalyst carrier structure obtained by a manufacturing method other than the wet papermaking method, for example. In addition, as long as the mineral fiber is contained, the fibrous shape is maintained until immediately before the firing temperature, and other fibrous materials different from the present embodiment are used as long as they melt at the firing temperature and cause a sintering action. Also good.

Next, more specific examples of the present invention will be described. Of course, the present invention is not limited to these examples, and can be arbitrarily changed or added.
(Example)
5 parts by weight of organic fiber, 80 parts by weight of inorganic filler (powder), 5 parts by weight of inorganic binder, 5 parts by weight of mineral fiber (fiber length 125 μm), and 5 parts by weight of organic binder are mixed in a predetermined amount of water to form a slurry. Then, a polymer flocculant was added therein to generate flocs, and paper production was performed to obtain a sheet-like porous structure. The porous structure was dried and then fired at about 1300 ° C. to obtain a sheet-shaped catalyst carrier structure according to the example.

(Comparative example)
After 5 parts by weight of organic fiber, 85 parts by weight of an inorganic filler (powder), 5 parts by weight of an inorganic binder and 5 parts by weight of an organic binder were mixed in a predetermined amount of water to obtain a slurry, The sheet-like catalyst carrier structure according to the comparative example was obtained by baking at about 1300 ° C. after papermaking and drying.

(Experiment)
In order to compare the physical properties of the example and the comparative example, strength evaluation by three-point bending (JIS R1601) was performed, and the results are shown in Table 1 below. According to Table 1, it can be seen that the bending strength of the example is significantly improved by the addition of the mineral fiber as compared with the comparative example.

  For a sheet-like catalyst carrier comprising an inorganic filler, an inorganic binder, and an aggregating agent and containing mineral fibers that retain a fibrous state until just before the firing temperature and melt at the firing temperature to produce a sintering action. As long as it is a structure, it can also be applied to those containing various other raw materials.

The flowchart which shows the manufacturing process of the structure for sheet-like catalyst carriers concerning an embodiment of the present invention.

Explanation of symbols

S1 Slurry production process S2 Flock production process S3 Sheeting process S4 Drying process S5 Firing process

Claims (4)

In the structure for a sheet-like catalyst carrier comprising an inorganic filler, an inorganic binder, and a flocculant and capable of supporting a predetermined catalyst,
A sheet-like catalyst carrier structure characterized by containing a mineral fiber that retains a fibrous form immediately before the firing temperature and melts at the firing temperature to produce a sintering action. The mineral fiber has a composition in which SiO ₂ is 35.0 to 45.0% by weight, Al ₂ O ₃ is 20.0 to 30.0% by weight, and CaO + MgO + FeO is 15.0 to 30.0% by weight. 2. The sheet-like catalyst carrier structure according to claim 1, wherein A slurry generation step of generating a slurry by mixing an inorganic filler and an inorganic binder in a predetermined amount of water;
A floc generating step of adding flocculant to the slurry obtained in the slurry generating step to generate floc;
A sheet forming step for producing a sheet-like porous structure by paper-making the floc obtained in the floc generating step;
A firing step of firing the sheet-like porous structure obtained in the sheeting step to obtain a sheet-like catalyst structure;
In the method for producing a sheet-like catalyst carrier structure by a wet papermaking method,
In the slurry generation step, in addition to the inorganic filler and the inorganic binder, the fiber shape is held until immediately before the firing temperature in the firing step, and mineral fibers that melt at the firing temperature and cause a sintering action are contained in the slurry. A sheet-like catalyst carrier structure characterized by being contained.   The method for producing a sheet-like catalyst carrier structure according to claim 3, wherein the flocculant added in the flock generation step comprises two polymer flocculants, a cationic polymer and an anionic polymer. .

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