JP2006205082A - Method for manufacturing catalyst, and liquid level sensor for manufacturing catalyst to be used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a catalyst by which the position of a catalyst component to be supported can be controlled for every pore highly precisely even in a catalyst base material having crooked pores when the catalyst component is supported into the pores of the catalyst base material by immersing a part of the catalyst base material in a catalyst component-containing liquid. <P>SOLUTION: In the method for manufacturing the catalyst by supporting the catalyst component on the catalyst base material 10 having a fine through-hole 11, the tip side of the liquid level sensor 1, which is provided with at least one pair of hyperfine electrodes 2a, 2b and an insulation sleeve having the thickness enough to be inserted into the through-hole 11, made of a flexible insulating material and having an opening 4, through which the tips of the electrodes 2a, 2b can be connected electrically to the outside while insulating the peripheries of the electrodes 2a, 2b is inserted into the through-hole 11 to a predetermined position 21 from one end side of the through-hole 11, and then the catalyst component-containing liquid 20 is introduced from the other end side of the through-hole 11, thereby detecting the liquid level when the catalyst component-containing liquid 20 reaches the position of the opening 4 and is contacted with the electrodes 2a, 2b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a catalyst in which a catalyst component is supported on a catalyst substrate having fine through holes, and a liquid level sensor for producing a catalyst used in the method.

  Conventionally, as a hydrogen generation reaction catalyst for generating hydrogen as a fuel in a fuel reforming system such as a fuel cell, an exhaust gas purification catalyst for purifying harmful components discharged from an internal combustion engine such as an automobile, etc. Various catalysts have been developed, and as such catalysts, those in which a metal oxide such as alumina and a noble metal such as platinum, rhodium, and palladium are supported on various catalyst substrates such as a honeycomb filter are generally used. in use. In the present specification, the components to be supported on the catalyst such as metal oxides and noble metals are collectively referred to as “catalyst components”.

  As a method for supporting the catalyst component on such a catalyst substrate, a part of the catalyst substrate is added to a liquid material such as a solution or dispersion containing the catalyst component (hereinafter collectively referred to as “catalyst component-containing liquid material”). In general, a method in which the catalyst component is supported in the pores of the catalyst substrate is generally employed. It was difficult. On the other hand, in recent years, particularly in the case of a catalyst used in a reaction vessel that involves heat exchange such as heating and endotherm, the accuracy of the catalyst loading position directly affects the heat exchange efficiency. There is an increasing demand for improving the accuracy of controlling the position to be carried. In addition, depending on the catalyst, it is necessary to coat multiple types of catalyst components in the pores. From this point of view, establishment of a technology that can control the catalyst component loading position in the pores with high precision is eagerly desired. Has been.

  From such a viewpoint, for example, in JP-A-2002-59010 (Patent Document 1), a moisture sensor is disposed above a catalyst base, and light having a wavelength absorbed by moisture (OH group) is emitted. A method for detecting the liquid level by reducing the intensity of reflected light is disclosed. However, as described in Patent Document 1, the method of detecting the liquid level from the outside of the base material with light or the like is difficult to apply to a base material in which the pores are bent. The catalyst component carrying position could not be controlled every time.

On the other hand, in Japanese Patent Laid-Open No. 63-134063 (Patent Document 2), when a catalyst is supported on a honeycomb type catalyst by electrical induction, a catalyst concentration distribution detection stylus probe is inserted into the pores to form a catalyst component. A method for detecting the concentration distribution of a liquid is disclosed. However, in the method of detecting the concentration distribution of the catalyst component as described in Patent Document 2, although the thickness of the catalyst layer formed in the pore can be controlled to some extent, the region in which the catalyst component is supported in the pore The boundary line with the unsupported area could not be controlled with high accuracy.
JP 2002-59010 A JP 63-134063 A

  The present invention has been made in view of the above-described problems of the prior art, and is a method of immersing a part of a catalyst base material in a catalyst component-containing liquid and supporting the catalyst component in the pores of the catalyst base material. In addition, the boundary line between the area in which the catalyst component is supported and the area in which the catalyst component is not supported in the pores can be controlled with high precision, and the control of the catalyst component loading position is controlled by the base material in which the pores are bent. The purpose of the present invention is to provide a catalyst production method that can be carried out with high accuracy for each pore, and a catalyst production liquid level sensor used in the method.

  As a result of intensive studies to achieve the above object, the present inventors have made at least a pair of ultrafine electrodes and a flexible insulating material having a thickness that can be inserted into the through hole of the catalyst base, Developed a liquid level sensor comprising an insulating sleeve having an opening that allows conduction to the outside of the tip of the ultrafine electrode while insulating the periphery of the ultrafine electrode, and the object is achieved by using the liquid level sensor. It has been found that this has been achieved, and the present invention has been completed.

That is, the method for producing a catalyst of the present invention is a method for producing a catalyst in which a catalyst component is supported on a catalyst substrate having fine through-holes,
It is made of at least a pair of ultrafine electrodes and a flexible insulating material having a thickness that can be inserted into the through hole, and can be electrically connected to the outside of the tip of the ultrafine electrode while insulating the periphery of the ultrafine electrode. In a state where the front end side of a liquid level sensor including an insulating sleeve having an opening to be inserted at a predetermined position from one end side of the through hole, the catalyst component-containing liquid material is introduced from the other end side of the through hole, The liquid level is detected when the catalyst component-containing liquid reaches the position of the opening and comes into contact with the ultrafine electrode.

The liquid level sensor for producing a catalyst of the present invention is a liquid level sensor used when a catalyst component is supported on a catalyst substrate having fine through-holes,
At least a pair of ultrafine electrodes;
An insulating sleeve having a thickness that can be inserted into the through-hole and made of a flexible insulating material and having an opening that allows electrical conduction to the outside of the tip of the ultrafine electrode while insulating the periphery of the ultrafine electrode When,
It is characterized by providing.

  In the liquid level sensor according to the present invention, it is preferable that the insulating sleeve is a laminated body made of a synthetic resin thin film, and the ultrafine electrode is a conductive thin film formed between the laminated bodies.

  In the production method of the catalyst of the present invention using the liquid level sensor of the present invention, the ultrafine electrode is insulated except for the opening by an insulating sleeve having a thickness that can be inserted into the through hole of the catalyst base to be treated. Therefore, the leading end side of the liquid level sensor can be inserted into a predetermined position from one end side of the through hole without causing erroneous detection due to contact between the ultrafine electrode and the inner wall of the catalyst base. Further, since the insulating sleeve of the liquid level sensor of the present invention is made of a flexible insulating material, the tip side of the liquid level sensor can be easily and surely brought to a predetermined position even when the pores are bent. Can be inserted.

  With the tip of the liquid level sensor inserted in a predetermined position of the through hole in this way, a part of the catalyst base material is immersed in the catalyst component-containing liquid, and the catalyst component-containing liquid is removed from the other end of the through-hole. When introduced, the liquid level of the catalyst component-containing liquid reaches the position of the opening of the liquid level sensor, and at the same time the catalyst component-containing liquid contacts the ultrafine electrode, and the electrical state before and after contact (conduction, resistance, voltage, etc.) Due to this difference, it is immediately and accurately detected that the liquid level has come to the position of the opening.

  And by stopping the introduction of the catalyst component-containing liquid based on the detection of the liquid level, the catalyst component is reliably prevented from being supported in the region above the liquid level at that time, and the catalyst in the pores The boundary line between the region where the component is supported and the region where the component is not supported is controlled with high accuracy. In addition, if a liquid level sensor is inserted for each pore that needs to be controlled, the catalyst component carrying position can be controlled with high accuracy for each pore.

  According to the present invention, in a method of immersing a part of a catalyst base in a catalyst component-containing liquid and supporting the catalyst component in the pores of the catalyst base, the region in which the catalyst component is supported in the pores The boundary line with the unsupported region can be controlled with high accuracy, and such control of the catalyst component supporting position can be performed with high accuracy for each pore even in the base material where the pores are bent. It is possible to provide a method for producing a possible catalyst and a liquid level sensor for producing a catalyst used in the method.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description and drawings, the same or corresponding elements are denoted by the same reference numerals, and duplicate descriptions are omitted.

  First, the liquid level sensor for producing a catalyst of the present invention will be described. FIG. 1 is a front view of a preferred embodiment of a liquid level sensor for catalyst production of the present invention, and FIG. 2 is a cross-sectional view taken along line AA of the liquid level sensor for catalyst production shown in FIG.

  A liquid level sensor 1 for producing a catalyst shown in FIGS. 1 and 2 includes a pair of ultrafine electrodes 2a and 2b aligned in parallel and an insulating sleeve 3 that integrally encloses the ultrafine electrodes 2a and 2b and insulates the surroundings. And. The material of the ultrafine electrodes 2a and 2b according to the present invention is not particularly limited as long as it is a conductive material that can be inserted into the through hole of the catalyst base material and can be finely processed. Electronic substrate materials such as copper, platinum, and gold Etc. Further, the specific shapes of the ultrafine electrodes 2a and 2b are not particularly limited, and in the present embodiment, the ultrafine electrodes 2a and 2b are formed of a copper foil that is a conductive thin film.

  The material of the insulating sleeve 3 is not particularly limited as long as it is a flexible insulating material that is durable to the catalyst component-containing liquid, and examples thereof include synthetic resins such as polyimide and epoxy. Further, the specific shape of the insulating sleeve 3 is not particularly limited, and in this embodiment, the insulating sleeve 3 is formed as a laminate of Kapton (registered trademark) which is a polyimide film. Furthermore, the width (or thickness) of the insulating sleeve 3 is not particularly limited as long as it is smaller than the size of the through hole of the catalyst base to be treated, but is generally preferably about 100 to 150 μm.

  And the opening part 4 is provided in the front-end | tip part of the insulation sleeve 3, and the front-end | tip part of the ultrafine electrodes 2a and 2b can be electrically connected through the opening part 4 to the exterior. In addition, a lead wire 5 is joined to the other ends of the ultrafine electrodes 2a and 2b, and the ultrafine electrodes 2a and 2b are electrically connected to a detector described later via the lead wire 5.

  Next, a preferred embodiment for carrying out the catalyst production method of the present invention using the catalyst production liquid level sensor 1 shown in FIGS. 1 and 2 will be described with reference to FIGS. 3 and 4.

  That is, first, the tip side of the liquid level sensor 1 is inserted into the through hole 11 of the catalyst base 10 to be treated. At that time, the insertion position of the liquid level sensor 1 is adjusted so that the opening 4 of the insulating sleeve 3 coincides with the predetermined position 21 where the liquid level of the catalyst component-containing liquid material 20 should be stopped. Since the ultrafine electrodes 2a and 2b are insulated by the insulating sleeve 3 except for the opening 4, when the liquid level sensor 1 is inserted into the through-hole 11, the ultrafine electrodes 2a and 2b and the inner wall of the catalyst base 10 are separated. The occurrence of false detection due to contact is completely prevented. In addition, since the liquid level sensor 1 is flexible, even if the pores 11 are bent as in the catalyst base 10 shown in FIGS. The distal end side can be inserted up to a predetermined position 21.

The catalyst substrate 10 to be treated in the present invention is not particularly limited as long as it is a catalyst substrate having fine through-holes. For example, a honeycomb filter, a high-density honeycomb (for example, 1200 cell / inch ² or more) A monolithic carrier substrate such as a microchannel) is a suitable treatment target. Further, the material of the catalyst base 10 is not particularly limited, and a base made of a ceramic such as cordierite, silicon carbide, mullite, or a base made of a metal such as stainless steel including chromium and aluminum is preferable. Listed as a target.

  Further, the catalyst component-containing liquid material 20 used in the present invention is not particularly limited, and catalyst components to be supported according to the target catalyst (for example, alumina, zirconia, titania, iron oxide, rare earth element oxide, alkali metal) Solutions and dispersions (colloidal solutions, slurries, etc.) containing metal oxides such as oxides and alkaline earth metal oxides, and noble metals such as platinum, rhodium, palladium, osmium, iridium and gold ) Is used as appropriate. Also, the solvent for preparing such a liquid is not particularly limited, and examples thereof include various solvents such as water and alcohol (for example, methanol, ethanol, ethylene glycol or the like alone or a mixed solvent).

  Next, the front end side of the liquid level sensor 1 is inserted into the predetermined position 21 of the through hole 11, and a voltage is applied between the ultrafine electrodes 2 a and 2 b by the power source 30 electrically connected via the lead wire 5. In this state, a part of the catalyst base material 10 is immersed in the catalyst component-containing liquid material 20 to introduce the catalyst component-containing liquid material 20 from the other end side of the through-hole 11 (the catalyst component content is indicated by the arrow in FIG. The introduction direction of the liquid 20 is shown). Then, as shown in FIG. 4, as soon as the liquid level of the catalyst component-containing liquid material 20 reaches the position (predetermined position 21) of the opening 4 of the liquid level sensor 1, the catalyst component-containing liquid material 20 immediately becomes the ultrafine electrodes 2a, 2b. A detector (for example, an ammeter) 31 that is in contact with the fine electrodes 2a, 2b and the lead wire 5 is used to open the opening 4 due to a difference in electrical state (for example, conduction) before and after the contact. It is immediately and accurately detected that the liquid level has come to the position.

  Then, by detecting that the liquid level of the catalyst component-containing liquid material 20 has reached the predetermined position 21 as described above, the introduction of the catalyst component-containing liquid material 20 is stopped, so that the region above the liquid level at that time is stopped. The catalyst component is reliably prevented from being supported, and the boundary line with the region where the catalyst component below the liquid level is supported (in FIG. 4, coincides with the one-dot chain line indicating the predetermined position 21) is highly accurate. Will be controlled. Next, the catalyst base on which the catalyst component is supported in this manner is dried under a known method and conditions, and further calcined as necessary to obtain a catalyst in which the catalyst component support position is controlled with high accuracy. It is done.

  As mentioned above, although the preferred embodiment of the liquid level sensor for catalyst manufacture of this invention and the manufacturing method of the catalyst of this invention using the same was described, this invention is not limited to the said embodiment. For example, in the above embodiment, a pair of ultrafine electrodes aligned in parallel is integrally wrapped by an insulating sleeve, but the configuration of the liquid level sensor is not limited to such a form. Each of the ultrafine electrodes may be wrapped with an insulating sleeve. Further, the number of ultrafine electrodes is not limited to two, and three or more ultrafine electrodes may be provided.

  In the above embodiment, an ammeter is used as a detector to measure the conduction before and after the contact between the liquid level and the electrode to detect the arrival of the liquid level. However, the present invention is not limited to such a form. For example, the change in voltage may be measured using a voltmeter, or the electrical resistance may be measured.

  Furthermore, in the above embodiment, the liquid level sensor is inserted into one through hole to detect the liquid level. However, the present invention is not limited to such a form. However, it is possible to insert a liquid level sensor into each of the necessary pores, and by doing so, it is possible to control the catalyst component carrying position with high accuracy for each of the pores.

  As described above, according to the catalyst production method of the present invention using the catalyst production liquid level sensor of the present invention, a part of the catalyst base material is immersed in the catalyst component-containing liquid to finely define the catalyst base material. In the method of supporting the catalyst component in the hole, the boundary line between the region in which the catalyst component is supported and the region in which the catalyst component is not supported can be controlled with high accuracy, and the control of the catalyst component supporting position is possible. Can be carried out with high accuracy for each pore even in a base material in which the pores are bent.

  Therefore, the present invention provides a hydrogen generation reaction catalyst for generating hydrogen as fuel in a separation membrane battery system such as a fuel cell, and exhaust gas purification for purifying harmful components discharged from an internal combustion engine such as an automobile. It is very useful as a technique for obtaining a catalyst for use.

It is a front view of suitable one Embodiment of the liquid level sensor for catalyst manufacture of this invention. It is AA sectional drawing of the liquid level sensor for catalyst manufacture shown in FIG. It is a schematic diagram which shows the state (state which has introduce | transduced the catalyst component containing liquid body) which implements suitable one Embodiment of the manufacturing method of the catalyst of this invention. It is a schematic diagram which shows the state (state which detected the liquid level) which is implementing suitable one Embodiment of the manufacturing method of the catalyst of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid level sensor for catalyst manufacture, 2a, 2b ... Fine electrode, 3 ... Insulating sleeve, 4 ... Opening part, 5 ... Lead wire, 10 ... Catalyst base material, 11 ... Through-hole, 20 ... Liquid containing catalyst component, 21 ... Predetermined position where the liquid level should be stopped, 30 ... Power source, 31 ... Detector.

Claims (4)

A method for producing a catalyst in which a catalyst component is supported on a catalyst substrate having fine through holes,
It is made of at least a pair of ultrafine electrodes and a flexible insulating material having a thickness that can be inserted into the through hole, and can be electrically connected to the outside of the tip of the ultrafine electrode while insulating the periphery of the ultrafine electrode. In a state where the front end side of a liquid level sensor including an insulating sleeve having an opening to be inserted at a predetermined position from one end side of the through hole, the catalyst component-containing liquid material is introduced from the other end side of the through hole, A method for producing a catalyst, comprising: detecting a liquid level when a catalyst component-containing liquid reaches the position of the opening and contacts the ultrafine electrode.   The method for producing a catalyst according to claim 1, wherein the insulating sleeve is a laminated body of synthetic resin thin films, and the ultrafine electrode is a conductive thin film formed between the laminated bodies. A liquid level sensor used when a catalyst component is supported on a catalyst substrate having fine through holes,
At least a pair of ultrafine electrodes;
An insulating sleeve having a thickness that can be inserted into the through-hole and made of a flexible insulating material and having an opening that allows electrical conduction to the outside of the tip of the ultrafine electrode while insulating the periphery of the ultrafine electrode When,
A liquid level sensor for producing a catalyst, comprising:   4. The liquid level sensor for producing a catalyst according to claim 3, wherein the insulating sleeve is a laminated body made of a synthetic resin thin film, and the ultrafine electrode is a conductive thin film formed between the laminated bodies.

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