JP2006224071A - Catalyst manufacturing method, slurry coating method, and catalyst manufacturing apparatus - Google Patents

Abstract

To provide a catalyst manufacturing method, a slurry coating method, and a catalyst manufacturing apparatus capable of accurately and easily detecting that a slurry has reached a desired coat width with a small-scale facility.
A catalyst manufacturing apparatus according to the present invention is a catalyst manufacturing apparatus 1 for coating a honeycomb 21 with a slurry 22, and a honeycomb holding base 14 for holding the honeycomb 21 so that its holes are oriented vertically, and the honeycomb. A high-intensity lamp 11 that emits light from above 21, a slurry push-up device 15 that pushes up the slurry 22 from below the honeycomb 21, and a light shielding box 12 that covers a range of the side surface of the honeycomb 21 with the desired height as the upper limit. , A light intensity sensor 13 for detecting the amount of light inside the light shielding box 12, and a controller 16 for stopping the pushing-up of the slurry 22 by the slurry pushing-up device 15 when the detected value of the light intensity sensor 13 becomes a predetermined value or less.
[Selection] Figure 1

Description

  The present invention relates to a catalyst manufacturing method for manufacturing an exhaust gas purifying catalyst for automobiles, a part thereof, and a slurry coating method for coating a honeycomb coated body with slurry, and a catalyst manufacturing apparatus used in those methods. . More specifically, the present invention relates to a catalyst manufacturing method, a slurry coating method, and a catalyst manufacturing apparatus for coating a porous coated body made of refractory ceramic or the like with a slurry.

  Conventionally, there is an exhaust gas purifying catalyst for purifying exhaust gas discharged from an engine such as an automobile before releasing it into the atmosphere. In general, the exhaust gas-purifying catalyst is manufactured by coating a ceramic or metal honeycomb having a large number of through holes in the exhaust gas passage direction with a slurry containing a catalyst component. In recent years, the regulation level of exhaust gas has risen, and the performance required for this exhaust gas purification catalyst has also increased. For example, there is a demand for improvement in purification efficiency when the catalyst is not sufficiently warm at the time of starting the engine, improvement in durability against high temperatures of exhaust gas, and the like.

  In order to meet these requirements, there is a manufacturing method in which two different types of slurry are separately applied from both sides of the honeycomb in the axial direction. For example, the first slurry is coated to a predetermined width by a coating method in which the axial direction of the honeycomb is vertically held and the slurry is pushed up into the honeycomb from below. Thereafter, the top and bottom of the honeycomb are turned over and the second slurry is coated in the same manner. However, it is not preferable that the two types of slurry overlap each other in the honeycomb or that the interval is too large. Therefore, in order to coat the slurry appropriately to the desired width in the axial direction of the honeycomb, a technique for detecting that the upper surface of the pushed-up slurry has reached the desired height is required.

  As an example of a method for detecting the reaching height of the slurry, for example, a technique using an image processing sensor using a CCD camera is disclosed (for example, see Patent Document 1). According to the technique described in this document, the arrival height of the slurry can be determined based on the color matching degree based on a color video signal from a CCD camera installed above the honeycomb.

Alternatively, a technique for detecting the arrival height of the slurry using a transmission line transmitter and a line receiver is also disclosed (for example, see Patent Document 2). In this technology, an X-ray transmitter and a CCD camera are provided on both sides in the diameter direction with a honeycomb interposed therebetween, and X-rays transmitted through the honeycomb are received by the CCD camera. Since the density on the image differs depending on the presence or absence of slurry, the boundary position can be determined.
JP 2002-59011 A JP 2002-242669 A

  However, the conventional techniques described above have the following problems. In the technique described in Patent Document 1, a change in color inside the honeycomb is detected to determine the upper end position of the slurry. Therefore, there is a problem that it cannot be used when the color difference between the honeycomb and the slurry is very small. In addition, since the CCD camera is detected from above the honeycomb, there is a problem that it is difficult to detect accurately when coating is performed with a relatively small width with respect to the axial length of the honeycomb. In addition, the height of the slurry entering each through-hole of the honeycomb is not necessarily constant, and may vary. In that case, there is a problem that an error may increase when only one point is detected by the CCD camera.

  In the technique described in Patent Document 2, X-rays are used. However, since X-rays are harmful to the human body, shielding facilities are required. For this reason, the equipment tends to be large and expensive. Furthermore, there was a problem that attention was required for handling. In addition, since it is necessary to install the X-ray transmitter and the CCD camera at the heights where the slurry is to be stopped, these positions must be changed to change the height, and the procedure is complicated. There was a problem.

  The present invention has been made to solve the problems of the conventional slurry coating method. That is, an object of the present invention is to provide a catalyst manufacturing method, a slurry coating method, and a catalyst manufacturing apparatus capable of accurately and easily detecting that the slurry has reached a desired coat width with a small-scale facility.

  The catalyst manufacturing method of the present invention made for the purpose of solving this problem is a method for manufacturing a catalyst by coating a slurry on a honeycomb-shaped object to be coated, in which the holes are vertically oriented. If the area where the amount of light leaking to the side of the coated body is below a predetermined value reaches a desired height, the slurry is pushed up from below the coated body while irradiating light from above the coated body. The push-up is stopped.

  According to the method for producing a catalyst of the present invention, the honeycomb-shaped coated body is held so that the holes are oriented vertically, and light is irradiated from above. Accordingly, light enters the coated body along the hole. At this time, if the honeycomb coated body is formed of a material that transmits light to some extent on its side, the light irregularly reflected inside the coated body leaks to the side. On the other hand, in the portion where the slurry is pushed up from below the coated body, the holes of the coated body are filled with the slurry. If the slurry is a material that does not easily transmit light, the amount of light leaking to the side of the coated body is reduced by the slurry in the portion filled with the slurry. Therefore, if the amount of light leaking to the side of the coated body is detected, it can be determined whether or not the slurry has reached that region. As a result, the catalyst manufacturing method can accurately and easily detect that the slurry has reached the desired coat width with a small-scale facility.

In the present application, the catalyst refers to a honeycomb coated body coated with a slurry containing a catalyst active, and corresponds to an exhaust gas purification catalyst for automobiles. The catalyst carrier refers to a honeycomb coated body coated only with a support layer made of alumina or the like that does not contain a catalyst active body. The carrier substrate is a honeycomb substrate coated with nothing. Refers to the coat body.
In addition, as a procedure for producing a catalyst, a method in which a carrier substrate is coated with a slurry containing both a carrier layer and a catalyst activator, and first, the carrier substrate is coated only with the carrier layer, and then the catalyst activity is further coated thereon. There is a method to coat the body. The present invention can be applied to any of these coating processes.

Furthermore, in the present invention, light irradiation and slurry push-up are performed in a state where the upper limit of the side surface of the coated body is covered with an opaque body, and the amount of light inside the opaque body is less than a predetermined value. It is desirable to stop the push-up when it becomes.
If it is such, what is necessary is just to observe the light quantity as the whole inside of an opaque body. When the upper surface of the slurry reaches the upper surface of the opaque body, the amount of light is greatly reduced, so that detection is easy.

Furthermore, in the present invention, it is desirable to use any one of a group including an LED lamp, a metal halide lamp, a mercury lamp, and a high-pressure sodium lamp as a light source for light irradiated from above the coated body.
Each of these light sources is a high-intensity lamp, and a sufficient amount of light that passes through the honeycomb-shaped coated body and leaks to the side can be obtained.

  The present invention also relates to a method for coating a honeycomb-shaped coated body with slurry, while holding the coated body so that its holes are oriented vertically and irradiating light from above the coated body. This extends to a slurry coating method in which the slurry is pushed up from the lower side of the body to be coated and the pushing-up is stopped when the region where the amount of light leaking to the side of the body to be coated reaches a desired height is reached.

  The present invention also relates to a catalyst manufacturing apparatus for coating slurry on a honeycomb-shaped body to be coated, the holding section for holding the body to be coated so that its holes are oriented vertically, and from above the body to be coated. Detects the light source that irradiates light, the push-up means that pushes up the slurry from below the coated body, the opaque body that covers the upper limit of the desired side of the coated body, and the amount of light inside the opaque body The present invention also extends to a catalyst manufacturing apparatus having a sensor for stopping and a stopping means for stopping the pushing-up of the slurry by the pushing-up means when the detected value of the sensor becomes a predetermined value or less.

  According to the catalyst production method, slurry coating method and catalyst production apparatus of the present invention, it is possible to accurately and easily detect that the slurry has reached the desired coating width with a small-scale facility.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the best mode for embodying the present invention will be described in detail with reference to the accompanying drawings. In this embodiment, the present invention is applied to a catalyst manufacturing apparatus for manufacturing a catalyst for automobiles.

  First, the honeycomb and slurry used in this embodiment will be described. The honeycomb is formed with a large number of through holes for allowing the exhaust gas to pass in the axial direction, and the outer shape and the shape of each through hole are not particularly limited. The material of the honeycomb needs to be able to transmit light in the direction intersecting with the through hole, and for example, a porous heat-resistant ceramic having a porosity of about 40% is suitable. In this embodiment, a metal honeycomb cannot be used. Slurries include all liquid materials, but materials with very high light transmittance are not suitable. Here, an aqueous solution containing a catalyst component such as a noble metal and an inorganic oxide such as activated alumina is used.

  As schematically shown in FIG. 1, the catalyst manufacturing apparatus 1 of this embodiment includes a high-intensity lamp 11, a light shielding box 12, a light intensity sensor 13, a honeycomb holding table 14, a slurry push-up device 15, and a controller 16. The catalyst manufacturing apparatus 1 is configured to immerse the slurry 22 into each through-hole to a predetermined width by pushing up the slurry 22 from below to the honeycomb 21 held so that the through-holes are in the vertical direction. It is a device for doing.

  The high-intensity lamp 11 is a high-intensity light source such as an LED lamp, a metal halide lamp, a mercury lamp, or a high-pressure sodium lamp. The high-intensity lamp 11 is provided above the honeycomb 21 in the figure, and projects onto the honeycomb 21 along the through hole. The light shielding box 12 is for blocking incident light from the outside, and covers the lower part of the honeycomb 21 to a predetermined height. The light intensity sensor 13 is for detecting the amount of light inside the light shielding box 12. For this purpose, the detection unit is provided inside the light shielding box 12.

  The honeycomb holding table 14 holds the honeycomb 21 and has a communication passage through which the slurry 22 communicates. The honeycomb holding table 14 holds the honeycomb 21 with its through hole oriented in the vertical direction. The slurry push-up device 15 includes a cylinder 15a and a piston 15b that can move in the vertical direction in the figure. The slurry 22 is held in the cylinder 15a, and the slurry 22 is pushed out into the honeycomb 21 by pushing the piston 15b upward in the figure. The controller 16 receives the detection result of the light intensity sensor 13 and instructs the slurry push-up device 15 to push up or stop.

  Next, a slurry coating process in which the slurry 22 is coated to a desired height of the honeycomb 21 by the catalyst manufacturing apparatus 1 of the present embodiment will be described with reference to FIG. First, the honeycomb 21 and the slurry 22 are prepared (step 1). Next, the honeycomb 21 is held on the honeycomb holding table 14, and the slurry 22 is filled in the slurry push-up device 15. Further, the light shielding box 12 is set on the honeycomb 21 (step 2). At this time, the light shielding height of the light shielding box 12 is made to coincide with the desired coat height of the slurry 22 with respect to the honeycomb 21.

  Next, the high-intensity lamp 11 is irradiated and detection by the light intensity sensor 13 is started (step 3). At this time, since the honeycomb 21 transmits light also in the direction intersecting with the through-holes, the irregularly reflected component of the light from the high-intensity lamp 11 passes through the side wall of the honeycomb 21 and reaches the light intensity sensor 13. Accordingly, at this stage, the detection value of the light intensity sensor 13 becomes a large value to some extent.

  Subsequently, the piston 15b of the slurry push-up device 15 is raised to push the slurry 22 into the honeycomb 21 (step 4). Since the slurry 22 has a low light transmittance, when the slurry 22 is filled in the through holes of the honeycomb 21, the light transmitted through the side walls of the honeycomb 21 to the outside decreases. That is, when viewed from the position of the light intensity sensor 13, the honeycomb 21 appears dark in the portion where the slurry 22 has reached.

  When the piston 15 b is further raised and the liquid level of the slurry 22 reaches the upper surface of the light shielding box 12, all the portions of the honeycomb 21 in the light shielding box 12 are covered with the slurry 21. Therefore, the light passing through the honeycomb 21 and reaching the light shielding box 12 is remarkably reduced, and the detection value of the light intensity sensor 13 is extremely small. The controller 16 instructs the slurry push-up device 15 to stop when the detected value of the light intensity sensor 13 becomes a predetermined value or less. Accordingly, the piston 15b is stopped (step 5).

  Thereafter, the excess slurry 22 is recovered by, for example, lowering the piston 15b and sucking it from below (step 6). There is also a collection method by blowing off from above. Finally, the honeycomb 21 coated with the slurry 22 is dried and fired (step 7). This completes the slurry coating process. When further coating other types of slurry from the other end, the upper and lower sides of the honeycomb 21 are turned back and held on the honeycomb holding table 14, and the slurry coating process is similarly performed.

"Example"
Next, an example of this catalyst manufacturing method is shown. In this embodiment, a small experimental honeycomb 21 was used, and different slurry 22 was applied separately on both ends thereof. The honeycomb 21 used here has a cylindrical shape with a diameter of 30 mm and a length of 50 mm, and the wall thickness is 6 mil. A cell with 400 cpsi cells is formed inside. As the high-intensity lamp 11, “BF-325P” manufactured by National was used.

  Further, in this embodiment, the light shielding box 12, the light intensity sensor 13, and the controller 16 are not used, but the visual inspection is performed. That is, the operator observed the honeycomb 21 from the side, and when the portion that appeared dark by the slurry 22 reached a predetermined height, the slurry pushing-up device 15 was stopped.

  In this embodiment, the upstream slurry 22A was coated 14 mm from one end of the honeycomb 21, and the downstream slurry 22B was coated 35mm from the other end of the honeycomb 21. When the two types of slurry 22A and 22B are applied separately from both ends of the honeycomb 21, it is preferable that a slight gap be formed between them. This is because if the coating is applied twice at the same position, the internal space of the through hole becomes narrow, and the exhaust gas permeability may deteriorate. At the target coat width in this experiment, the gap is 1 mm.

  The upstream slurry 22A was prepared as follows. First, 300 g of ceria-zirconia-lanthana composite oxide (for example, Ce: Zr: La = 60: 35: 5) was dispersed and stirred in 500 ml of ion-exchanged water. Furthermore, 204.5 g of a dinitrodiammine platinum nitrate solution (for example, Pt 4.4 wt%) was added, stirred for 2 hours, dried, and calcined at 450 ° C. for 2 hours. This powder is Pt (3 wt%) / CZL. Next, 100 g of γ-alumina, the above Pt (3 wt%) / CZL 300 g, 200 g of alumina sol (solid content 10 wt%) were mixed, 20 g of ion-exchanged water was added, and the mixture was mixed for 15 minutes using a ball mill.

  The downstream slurry 22B was prepared as follows. First, 400 g of zirconia-Lantana composite oxide (for example, Zr: La = 95: 5) was dispersed and stirred in 600 ml of ion exchange water. Further, 71 g of a rhodium nitrate solution (for example, Rh 2.8 wt%) was added, stirred for 2 hours, dried, and calcined at 450 ° C. for 2 hours. This powder is Rh (0.5 wt%) / ZL. Next, 80 g of γ-alumina, Rg (0.5 wt%) / ZL 400 g and 240 g of alumina sol (solid content 10 wt%) were mixed, 32 g of ion exchange water was added, and the mixture was mixed for 15 minutes using a ball mill.

  When these were prepared, the honeycomb 21 was held on the honeycomb holding table 14, and the slurry 22 A was first filled in the slurry push-up device 15. The high-intensity lamp 11 was irradiated from the upper end of the honeycomb 21, and the slurry 22 </ b> A was injected while viewing from the side of the honeycomb 21. And when the dark part in the honeycomb 21 reached 14 mm, the slurry pushing-up device 15 was stopped. Further, excess slurry 22A was removed by suction from the injection side. Furthermore, it dried at 120 degreeC for 30 minutes, and baked at 250 degreeC for 1 hour.

  Next, the fired honeycomb 21 was held on the honeycomb holding table 14 upside down, and the slurry push-up device 15 was filled with the slurry 22B. Similarly to the above, the slurry 22B was injected, and when the dark part in the honeycomb 21 reached 35 mm, the slurry push-up device 15 was stopped. Further, excess slurry 22B was removed by suction from the injected side, and dried and fired in the same manner as described above.

  FIG. 3 shows the inside of the honeycomb 21 coated with two types of slurry 22A, 22B according to this embodiment. This is the result of dividing the coated honeycomb 21 into half halves and checking the inside. That is, the upstream slurry 22A was coated from the one end side of the honeycomb 21 to 13.1 mm, and the downstream slurry 22B was coated from the other end side of the honeycomb 21 to 36.0 mm. A gap of 0.9 mm was formed between the two types of slurries 22A and 22B, and the coating state was very good.

  As described above in detail, according to the catalyst manufacturing apparatus 1 of the present embodiment, the high-intensity lamp 11 irradiates the light from the upper part of the honeycomb 21 and detects the light that passes through the side surface of the honeycomb 21 and leaks to the outside. Since the light shielding box 12 and the light intensity sensor 13 are used, it can be easily grasped that the coating height of the slurry 22 has reached the upper surface of the light shielding box 12. Furthermore, since the slurry push-up device 15 is controlled by the controller 16, the push-up of the slurry 22 can be automatically stopped when the detection value of the light intensity sensor 13 becomes a predetermined value or less. When changing the coat height, it is only necessary to change the lid position of the light shielding box 12. Therefore, the catalyst manufacturing apparatus 1 can accurately and easily detect that the slurry 22 has reached the desired coat width with a small-scale facility.

In addition, this form is only a mere illustration and does not limit this invention at all. Therefore, the present invention can naturally be improved and modified in various ways without departing from the gist thereof.
For example, although the slurry push-up device 15 has the piston 15b, it is not limited to the piston type as long as the slurry can be pushed up.
Further, for example, in this embodiment, the light intensity sensor 13 detects the light intensity in the light shielding box 12 and the controller 16 automatically controls the slurry push-up device 15, but these can also be performed manually. For example, the operator may check the detection value of the light intensity sensor 13 and manually stop the piston 15b. Alternatively, as performed in the embodiment, when the operator observes the honeycomb 21 from the side and a portion that looks dark due to the slurry 22 reaches a predetermined height, the slurry push-up device 15 can be stopped.
Further, for example, in the present embodiment, the method for producing a catalyst by coating the honeycomb 21 which is a ceramic carrier substrate with the slurry 22 containing the catalyst component has been described as an example. In addition to this method, the honeycomb 21 which is a carrier base material is first coated only with a support layer made of alumina or the like which does not contain a catalyst component, and then a slurry containing the catalyst component is further coated thereon. There is also a manufacturing method. In this manufacturing method, the present invention is also applied to a coating process for coating the honeycomb 21 only with the supporting layer not containing the catalyst component, a coating process for coating the honeycomb having the supporting layer formed on the carrier base material with the slurry containing the catalyst component, and the like. The invention is applicable.

It is a schematic block diagram which shows the catalyst manufacturing apparatus of this form. It is process drawing which shows the catalyst manufacturing installation method of this form. It is explanatory drawing which shows the example of the state by which the slurry was coated by the catalyst manufacturing method of this form.

Explanation of symbols

1 Catalyst production equipment 11 High-intensity lamp (light source)
12 Shading box (opaque)
13 Light intensity sensor (sensor)
14 Honeycomb holder (holding part)
15 Slurry push-up device (push-up means)
16 Controller (stopping means)
21 Honeycomb (Coating body)
22 Slurry

Claims (5)

In a method for producing a catalyst by coating a honeycomb-shaped substrate with slurry,
Hold the coated body so that the holes are oriented vertically,
The slurry is pushed up from below the coated body while irradiating light from above the coated body,
A method for producing a catalyst, characterized in that the pushing-up is stopped when a region where the amount of light leaking to the side of the object to be coated reaches a desired height is reached. The method for producing a catalyst according to claim 1,
Irradiate light and push up the slurry with the opaque body covering the range with the upper limit of the desired height on the side of the coated body,
The method for producing a catalyst, wherein the pushing-up is stopped when the amount of light inside the opaque body becomes a predetermined value or less. In the catalyst manufacturing method of Claim 1 or Claim 2,
A method for producing a catalyst, characterized in that any one of a group including an LED lamp, a metal halide lamp, a mercury lamp, and a high-pressure sodium lamp is used as a light source of light irradiated from above the coated body. In a method of coating slurry on a honeycomb coated body,
Hold the coated body so that the holes are oriented vertically,
The slurry is pushed up from below the coated body while irradiating light from above the coated body,
A slurry coating method, wherein pushing up is stopped when a region where the amount of light leaking to the side of the object to be coated reaches a desired height is reached. In a catalyst manufacturing apparatus for coating slurry on a honeycomb-shaped coated body,
A holding portion for holding the coated body so that the hole is oriented vertically;
A light source that emits light from above the coated body;
A push-up means for pushing up the slurry from below the coated body;
An opaque body covering a range of the side of the body to be coated with a desired height as an upper limit;
A sensor for detecting the amount of light inside the opaque body;
A catalyst manufacturing apparatus comprising: a stopping unit that stops the pushing-up of the slurry by the pushing-up unit when a detection value of the sensor becomes a predetermined value or less.

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