JP7511427B2 - Electrode catalyst manufacturing system and manufacturing method - Google Patents

Description

The present invention relates to a manufacturing system and method for electrode catalysts.

So-called solid polymer electrolyte fuel cells (hereinafter referred to as "PEFC" as necessary) have an operating temperature of about room temperature to 80°C. In addition, PEFCs can be made lightweight because inexpensive general-purpose plastics can be used for the components that make up the fuel cell body. Furthermore, PEFCs can have a thin solid polymer electrolyte membrane, which reduces electrical resistance and makes it relatively easy to reduce power generation losses. As such, PEFCs have many advantages, making them suitable for use in fuel cell vehicles, home cogeneration systems, and the like.

As an electrode catalyst for PEFC, for example, an electrode catalyst in which platinum (Pt) or a platinum (Pt) alloy is supported on a carbon carrier is known. When using such an electrode catalyst as an electrode catalyst for a fuel cell, if the electrode catalyst contains a large amount of impurities derived from the raw materials or impurities mixed in from the manufacturing equipment, sufficient catalytic activity cannot be obtained, the catalyst layer may corrode, and the life of the fuel cell may be shortened. For this reason, it is preferable to keep the impurity content of the electrode catalyst, especially the chlorine content, low. Here, examples of impurities include chemical species belonging to halogens (ions and their salts, etc.), organic substances (organic acids, their salts, condensates of organic acids), etc.

For these reasons, a process for removing chlorine may be carried out after the production of the electrode catalyst precursor, which is the raw material for the electrode catalyst. In such cases, a process for drying the electrode catalyst precursor after the washing process is carried out. For example, Patent Documents 1 and 2 state that a shelf dryer, rotary dryer, flash dryer, spray dryer, stirring dryer, freeze dryer, etc. can be used as a drying method after washing.

JP 2013-158674 A JP 2014-42910 A

For example, when drying the electrode catalyst precursor using a shelf dryer, in order to perform drying efficiently, the wet electrode catalyst precursor lumps are crushed into small pieces and then placed in the shelf dryer for drying, and even after drying, a process of crushing the dried electrode catalyst precursor lumps into small pieces is sometimes performed. This conventional method of drying the electrode catalyst precursor requires a dedicated crusher for crushing the wet electrode catalyst precursor after washing and a hammer mill for crushing the dried electrode catalyst precursor, and the electrode catalyst precursor needs to be transferred from the crusher to the dryer and from the dryer to the hammer mill. However, platinum, which constitutes the electrode catalyst precursor, has high activity and may burn if it suddenly comes into contact with oxygen in the air, so careful work is required. In addition, the method of drying the electrode catalyst precursor using a shelf dryer has the problem that the drying speed is slow and takes a long time because the electrode catalyst precursor is left stationary and dried by radiant heat transfer. Patent documents 1 and 2 describe that an agitator dryer can be used to dry the fuel cell catalyst, but do not describe the specific configuration or operating conditions of the agitator dryer.

The present invention was made in consideration of these circumstances, and provides a manufacturing system and manufacturing method for electrode catalysts that can significantly reduce the effort and time required to manufacture electrode catalysts by eliminating the need for workers to transfer electrode catalyst precursors and shortening the drying time of the electrode catalyst precursors.

In order to solve such problems, the present invention provides:
an electrode catalyst precursor manufacturing apparatus for manufacturing an electrode catalyst precursor, which is a raw material for an electrode catalyst;
a cleaning device for cleaning the electrode catalyst precursor;
a drying device that dries the electrode catalyst precursor washed by the washing device using an agitation treatment device equipped with an agitation blade having discontinuous inclined paddle blades,
The drying device is
an introduction step of introducing the electrode catalyst precursor into a vessel body of the stirring treatment device;
a drying step of heating the container body while reducing the pressure, and stirring and mixing the electrode catalyst precursor in the container body with the stirring blade, thereby drying the electrode catalyst precursor;
a cooling step of cooling the electrode catalyst precursor by cooling and reducing the pressure of the container body and stirring and mixing the electrode catalyst precursor in the container body with the stirring blade;
a gradual oxidation step of supplying air into the container body and subjecting the electrode catalyst precursor to a gradual oxidation treatment;
and a removal step of removing the electrode catalyst precursor from the container body.

The electrode catalyst manufacturing system includes:
the stirring blade includes a main shaft that is rotated by a drive device to rotate the stirring blade, the inclined paddle blade that stirs and mixes the electrode catalyst precursor in the container body, and a rotor support that connects the main shaft and the inclined paddle blade,
The rotor shaft and the rotor support are formed in a hollow tubular shape,
The rotor support has a gas outlet hole on the lower side of the tip,
The rotating shaft may be connected to a gas flow path.

The present invention also provides a method for producing a method for manufacturing a semiconductor device comprising the steps of:
an electrode catalyst precursor producing step of producing an electrode catalyst precursor which is a raw material for the electrode catalyst;
a washing step of washing the electrode catalyst precursor;
a drying step of drying the electrode catalyst precursor after the washing step by using an agitation treatment device equipped with an agitation blade having discontinuous inclined paddle blades,
The drying step comprises:
a drying step of drying the electrode catalyst precursor by heating and reducing the pressure of a container body of the stirring treatment device and stirring and mixing the electrode catalyst precursor in the container body with the stirring blade;
a cooling step of cooling the electrode catalyst precursor by cooling and reducing the pressure of the container body and stirring and mixing the electrode catalyst precursor in the container body with the stirring blade;
and a gradual oxidation step of supplying air into the container body and subjecting the electrode catalyst precursor to a gradual oxidation treatment.

In the method for producing an electrode catalyst,
The method further includes a removal step of removing the electrode catalyst precursor from the container body,
In the method for producing an electrode catalyst, the removal step may include a scraper step of ejecting gas downward from gas ejection holes provided at the tip of a rotor support that supports the inclined paddle blades.

In the method for producing an electrode catalyst,
a first analysis step of performing a physical property analysis of the electrode catalyst precursor obtained through the drying step;
a reslurry step of mixing the electrode catalyst precursor obtained through the drying step with ion-exchanged water to prepare a slurry again;
A catalyst cake preparation step of drying the slurry obtained through the reslurry step to prepare a plurality of solid catalyst cakes having a moisture content adjusted to a predetermined range;
It may further include.

In the manufacturing method of the electrode catalyst, the stirring drying device used in the catalyst cake preparation step may be the stirring treatment device.

In the method for producing an electrode catalyst, a reactor equipped with a stirring device may be used in the reslurry step.

In the method for producing an electrode catalyst, the reactor may be the stirring treatment device.

In the manufacturing method of the electrode catalyst, the water content of the catalyst cake may be less than 80 wt%.

The manufacturing method of the electrode catalyst may further include a second analysis step of measuring the moisture content of the catalyst cake obtained through the catalyst cake preparation step.

The electrode catalyst manufacturing system and manufacturing method of the present invention eliminates the need for workers to transfer electrode catalyst precursors and shortens the drying time of the electrode catalyst precursors, significantly reducing the effort and time required to manufacture electrode catalysts with low halogen content, particularly low chlorine content.

1 is a block diagram showing a preferred embodiment of a system for producing an electrode catalyst according to the present invention. 1 is a schematic diagram showing a preferred embodiment of a drying device in a production system and a production method for an electrode catalyst of the present invention. 1 is a schematic diagram showing a preferred embodiment of an agitating blade of a drying device in a production system and a production method for an electrode catalyst of the present invention. FIG. 1 is a schematic diagram showing a preferred embodiment of an operating state of a drying device in a drying step of a production system and a production method for an electrode catalyst according to the present invention. FIG. 1 is a schematic cross-sectional view showing an example of the structure of an electrode catalyst (core-shell catalyst) that can be produced by the electrode catalyst production system and production method of the present invention. FIG. 2 is a schematic cross-sectional view showing another example of the structure of an electrode catalyst (core-shell catalyst) that can be produced by the electrode catalyst production system and production method of the present invention. FIG. 2 is a schematic cross-sectional view showing another example of the structure of an electrode catalyst (core-shell catalyst) that can be produced by the electrode catalyst production system and production method of the present invention. FIG. 2 is a schematic cross-sectional view showing another example of the structure of an electrode catalyst (core-shell catalyst) that can be produced by the electrode catalyst production system and production method of the present invention. FIG. 1 is a flow chart showing a preferred embodiment of the flow of a method for producing an electrode catalyst of the present invention. FIG. 2 is a flow chart showing a preferred embodiment of the flow of a drying step in the method for producing an electrode catalyst of the present invention. FIG. 2 is a block diagram showing a further preferred embodiment of the electrode catalyst manufacturing system of the present invention. FIG. 2 is a flow chart showing a preferred embodiment of the flow of the reslurry step in the method for producing an electrode catalyst of the present invention.

Below, a preferred embodiment of the electrode catalyst manufacturing system and manufacturing method of the present invention will be described with reference to the drawings.

<Electrode catalyst manufacturing system>
Fig. 1 is a block diagram showing an outline of an electrode catalyst manufacturing system according to the first embodiment. The electrode catalyst manufacturing system 10 includes an electrode catalyst precursor manufacturing apparatus 12 for manufacturing an electrode catalyst precursor, which is a raw material for an electrode catalyst 1 (see Fig. 5), a washing apparatus 13 for washing the electrode catalyst precursor, and a drying apparatus 14 for drying an electrode catalyst precursor 41 (see Fig. 10) after washing in the washing apparatus 13, by an agitation treatment apparatus equipped with an agitation blade having discontinuous inclined paddle blades.

(Electrode catalyst precursor manufacturing equipment)
The electrode catalyst precursor manufacturing apparatus 12 manufactures an electrode catalyst precursor, which is a raw material for the electrode catalyst 1. The electrode catalyst precursor manufacturing apparatus 12 includes a reaction process execution means 21 that executes a reaction process for manufacturing an electrode catalyst precursor. In the reaction process, an electrode catalyst precursor, which is a raw material for the electrode catalyst 1, is manufactured by supporting the catalyst components (core part 4, shell part 5) of the electrode catalyst 1 on the carrier 2 (see FIG. 5). The manufacturing method of the electrode catalyst precursor is not particularly limited as long as it is a method that can support the catalyst components of the electrode catalyst 1 on the carrier 2. For example, there can be mentioned an impregnation method in which a solution containing the catalyst components of the electrode catalyst 1 is contacted with the carrier 2 to impregnate the carrier 2 with the catalyst components, a liquid phase reduction method in which a reducing agent is added to a solution containing the catalyst components of the electrode catalyst 1, an electrochemical deposition method such as an underpotential deposition (UPD) method, a chemical reduction method, a reduction deposition method using adsorbed hydrogen, a surface leaching method of an alloy catalyst, a displacement plating method, a sputtering method, a vacuum deposition method, or the like.

(Cleaning device)
The washing device 13 washes the electrode catalyst precursor produced in the electrode precursor production apparatus 12. The washing device 13 includes a washing step execution means 22 that executes a washing step for washing and filtering the electrode catalyst precursor produced in the electrode precursor production apparatus. As the washing method and filtering method in the washing step, a conventional centrifuge (not shown) or a washing method and filtering method using a filter press (not shown) can be used.

(Drying device)
2 shows a schematic configuration of the drying device 14 according to the present invention. The drying device 14 dries the electrode catalyst precursor cleaned by the above-mentioned cleaning device 13 using an agitation processing device 101 equipped with an agitation blade 104. The agitation processing device 101 as a drying device mainly comprises a container body 102 in the form of an inverted cone-shaped hollow container, a decompression mechanism 103 for decompressing the inside of the container body 102, and the agitation blade 104. The upper part of the container body 102 is covered with a lid 105 that is detachably attached to the container body 102, a jacket 106 is provided on the peripheral wall through which steam S flows as a heating medium for heating the inside of the container body 102, and supports 110, 110 for supporting the container body 102 are provided on the outer surface. Load cells 112, 112 capable of checking weight changes are provided on the undersides of the supports 110, 110, and the container body 102 is suspended at the installation location by installing the supports 110, 110 at the installation location via the load cells 112, 112. A stirring blade 104 is provided to stir the inside of the container body 102, and a drive device 107 for the stirring blade 104 is provided on a lid 105 at the top of the container body 102, and an opening 108 for taking out the electrode catalyst precursor in the container body 102 is formed at the conical apex, which is the lower end of the container body 102. A take-out valve 109 is provided at this opening 108, and the electrode catalyst precursor in the container body 102 is taken out by operating and opening the take-out valve 109. A supply port 111 is provided on the lid 105 at the top of the container body 102, and a manhole 115 is provided at the supply port 111 as an inlet, and the electrode catalyst precursor is supplied to the container body 102 by operating and opening the manhole 115. The jacket 106 is provided with a heating medium inlet 113 for injecting steam S and a heating medium outlet 114 for discharging steam S. The container body 102 is provided with a temperature indicating regulator 116, which monitors the temperature of the electrode catalyst precursor in the container body 102 and adjusts the amount of steam S supplied to the heating medium inlet 113 and the amount of steam S discharged from the heating medium outlet 114, thereby adjusting the temperature of the electrode catalyst precursor in the container body 102. The heating medium inlet 113 is configured to be able to inject a cooling medium C in addition to the heating medium, and the heating medium outlet 114 is configured to be able to discharge the cooling medium C in addition to the heating medium.

Figure 3A shows a schematic diagram of the agitator blade 104. The agitator blade 104 includes a rotating main shaft 122 that extends through the center of the lid 105, a plurality of agitator blades 123 and auxiliary blades 124 that are connected to the rotating main shaft 122 so as to be arranged in multiple stages and rotate together with the rotating main shaft 122, and a ribbon blade 125, and the rotating main shaft 122, the agitator blade 123, the auxiliary blades 124, and the ribbon blade 125 are integrally configured.

The rotating main shaft 122 is incorporated into the driving device 107 via a seal unit 121 (see FIG. 2). Driving the driving device 107 rotates the rotating main shaft 122, which in turn rotates the stirring blade 123, auxiliary blade 124, and ribbon blade 125 that are integral with the rotating main shaft 122. Thus, the rotating main shaft 122 rotates the stirring blade 104 as the rotating main shaft 122 is rotated by the driving device 107. The rotating main shaft 122 is formed in a hollow tubular shape, and is connected to an arm 128, which is also formed in a hollow tubular shape and will be described later, so that it can flow freely. The end of the rotating shaft 122 on the drive unit 107 side is connected to a flow path for the gas G for the scraper, such as nitrogen gas, normal pressure air, a mixed gas in which nitrogen gas and oxygen gas are mixed at an arbitrary ratio to adjust the oxygen gas concentration, a mixed gas in which nitrogen gas and air are mixed at an arbitrary ratio to adjust the oxygen gas concentration, or a high pressure air flow path, and is configured to inject the gas G into the rotating shaft 122, for example, by the gradual oxidation process execution means 34 or the extraction process execution means 35 described below.

Referring to FIG. 2, the driving device 107 uses a geared motor or the like, and is adapted to rotate the stirring blade 104 by adjusting the rotation speed to a predetermined value. The driving device 107 also includes a position detection device (not shown) that detects the rotation and position of the stirring blade 104. The sealing unit 121 is equipped with, for example, a dry seal and a mechanical seal, and is configured to be able to handle processing even when the inside of the container body 102 is at a high vacuum or high pressure.

Returning to FIG. 3A, the agitator blade 123 is composed of a blade plate 127 as a discontinuous inclined paddle blade, and an arm 128 as a rotor support that connects the blade plate 127 and the main shaft 122. The arm 128 is formed so that its length gradually shortens from the top to the bottom in the axial direction of the main shaft 122, and is configured so that when the agitator blade 104 is placed in the container body 102, each blade plate 127 is placed along the inner wall surface of the conical container body 102 with a small clearance. Also, as shown in FIG. 3B, each arm 128 is provided at a position that forms an equal angle α with respect to the upper and lower arms 128. In this embodiment, the equal angle α is 120°, but other angles may be used. In addition, a gas ejection hole 129 for the scraper is provided on the underside of the tip of each arm 128, and when gas G is injected into the rotating main shaft 122 from the gas G flow path described above, the gas G is ejected from each gas ejection hole 129 through the rotating main shaft 122 and each arm 128, preventing the electrode catalyst precursor from stagnation during the removal step S35 described below.

The vane 127 is paddle-shaped and is configured as a flat plate formed of short sides with a constant width and long sides that are curved parallel to the inner wall surface of the container body 102. Each vane 127 is connected to each arm 128 with a predetermined inclination, and is configured so that the electrode catalyst precursor rises along the inner wall surface of the container body 102 by each vane 127 rotating in the direction of the arrow A in FIG. 3A inside the container body 102. The predetermined inclination is preferably 15° to 45°.

As shown in Figures 3A and 3B, the auxiliary blades 124 are rectangular flat plates and are provided above or below the agitating blades 123 along the rotation axis of the rotating main shaft 122. Therefore, like the agitating blades 123, each auxiliary blade 124 is provided at an equal angle α to the upper and lower auxiliary blades 124. In Figure 3A, the auxiliary blades 124 rotate in the direction of the arrow A inside the container body 102, eliminating poor mixing in the center of the container body 102 and suppressing adhesion of the electrode catalyst precursor to the rotating main shaft 122 and arm 128.

The ribbon blade 125 is provided below the rotating main shaft 122 and is securely fixed to the rotating main shaft 122 by the arm 141. The ribbon blade 125 is formed in a spiral shape, and instead of providing a center shaft inside the spiral, the spirals are reinforced by the reinforcing parts 142, 143. By configuring in this way, it is possible to alleviate the dense configuration compared to a configuration in which the rotating main shaft 122 penetrates the center of the container body 102, so that when the electrode catalyst precursor in the container body 102 is taken out from the opening 108 in the removal process, the electrode catalyst precursor can pass through the center of the ribbon blade 125, reducing the resistance during removal and shortening the removal time, and also suppressing adhesion of the electrode catalyst precursor to the lower part of the container body 102. In FIG. 3A, the ribbon blade 125 is configured to rotate in the direction of the arrow A inside the container body 102 so that the electrode catalyst precursor rises along the inner wall surface of the container body 102, promoting the stirring of the electrode catalyst precursor in the lower part of the container body 102.

Returning to FIG. 2, the decompression mechanism 103 is described below. 131 is a bag filter that is provided in the exhaust hole 132 of the lid 105, and liquid and gas evaporated from the electrode catalyst precursor in the container body 102 are discharged through the bag filter 131. 133 is a condenser that condenses the liquid flowing from the bag filter 131. The condenser 133 and the exhaust hole 132 of the lid 105 are connected by a connecting pipe 135 through the bag filter 131. 134 is a vacuum pump that is connected to the condenser 133 by a suction pipe 136, and is configured so that liquid and gas evaporated from the electrode catalyst precursor flow from the container body 102 to the bag filter 131 and the condenser 133 by driving the vacuum pump 134. A pressure indicator regulator 137 is provided in the connecting pipe 135 to adjust the pressure in the container body 102 when performing reduced pressure drying. The adjustment signal from the pressure indicator regulator 137 adjusts the adjustment valve 138 on the suction pipe 136 to adjust the degree of vacuum sucked by the vacuum pump 134. The gas and steam flowing from the bag filter 131 via the connection pipe 135 is condensed in the condenser 133, and the components that are easy to condense are separated from the gas as condensed liquid. The separated gas is sucked into the vacuum pump 134 via the suction pipe 136 and exhausted from the vacuum pump 134. An air blow nozzle (not shown) may be provided at the bottom of the container body 102, and the container body 102 may be configured to return from a reduced pressure state to a normal pressure state by introducing an inert gas or air through the air blow nozzle.

As shown in the block diagram of FIG. 1 and the flow chart of FIG. 10, the drying device 14 is equipped with an introduction process execution means 31, a drying process execution means 32, a cooling process execution means 33, a gradual oxidation process execution means 34, and a removal process execution means 35, which are means for respectively executing an introduction process S31, a drying process S32, a cooling process S33, a gradual oxidation process S34, and a removal process S35. Each of the processes S31 to S35 is described below.

[Introduction process]
The introduction step S31 is a step of introducing the washed electrode catalyst precursor into the drying device 14, and is executed by the introduction step execution means 31. Explaining with reference to FIG. 4A, the introduction step execution means 31 operates and opens the manhole 115 of the stirring processing device 101, and introduces the electrode catalyst precursor having a predetermined moisture content into the container body 102 from the supply port 111. It is preferable that the moisture content of the electrode catalyst precursor is measured in advance. As shown in FIG. 4A, the method of introducing the electrode catalyst precursor may be by manual operation using a funnel or the like, or may be directly introduced without human hands from a pipe or belt conveyor through which the electrode catalyst precursor is transported. Here, the weight of the introduced electrode catalyst precursor is measured by the load cells 112, 112. Note that, before this introduction step S31, a preheating step may be performed in which steam S is injected into the jacket 106 to preheat the inside of the container body 102 to a predetermined temperature. Thereafter, the introduction step execution means 31 operates the manhole 115 to close it, sealing the container body 102, and the introduction step S31 is completed.

[Drying process]
The drying step S32 is a step of drying the electrode catalyst precursor introduced into the container body 102 (a step of performing so-called vacuum drying), and is executed by the drying step execution means 32. Explained with reference to Fig. 4B together with Fig. 2 etc., the drying step execution means 32 drives the drive device 107 to rotate the stirring blade 104, drives the vacuum pump 134 to evacuate and reduce the pressure inside the container body 102, and adjusts the operating pressure to a predetermined pressure with the pressure indicating regulator 137 to stir and mix the electrode catalyst precursor. The rotation speed of the stirring blade 104 is preferably 50 to 100 revolutions per minute, and the operating pressure is preferably 5 to 20 kPa (gauge pressure). Furthermore, the drying process execution means 32 injects steam S from the heating medium inlet 113 into the jacket 106 using the temperature indicating regulator 116, and heats the container body 102 by conductive heat transfer of the steam S, thereby adjusting the electrode catalyst precursor in the container body 102 to a predetermined temperature (drying temperature) and drying it. The drying temperature is preferably a value selected from the range of 50 to 150° C. The operating pressure and heating temperature may be changed during the drying process to adjust the drying time by measuring the temperature (product temperature) of the electrode catalyst precursor and observing the degree of change in the product temperature.

To explain in more detail the circulating flow of the electrode catalyst precursor in the container body 102 in the drying step S32, the stirring blade 104 rotates, causing the ribbon blade 125 to raise the electrode catalyst precursor along the inner wall surface of the lower part of the container body 102, and the blade plate 127 causes the electrode catalyst precursor to rise further along the inner wall surface of the container body 102. At this time, the tip of the blade plate 127, which is a discontinuous inclined paddle blade arranged in multiple stages, applies a shear force to the electrode catalyst precursor, dispersing and mixing the electrode catalyst precursor and suppressing the generation of agglomerates. In addition, since the blade of the blade plate 127 is not continuous, the rotation action of the electrode catalyst precursor can be reduced, and the generation of agglomerates can be suppressed.
The blades 127, which are discontinuous inclined paddle blades, can reduce the occurrence of a "vortex," a phenomenon in which the electrode catalyst precursor is stirred up to a high position around the container body 102 while dropping deep in the center of the container body 102, and can suppress the occurrence of segregation. The electrode catalyst precursor then turns back at the top of the container body 102 and is sucked into the center of the rotating shaft of the rotating main shaft 122, forming a flow that moves downward, but at the center of the rotating shaft, a stirring effect is applied to the electrode catalyst precursor by the auxiliary blades 124, which fluidizes the electrode catalyst precursor around the rotating main shaft 122 and suppresses adhesion of the electrode catalyst precursor to the rotating main shaft 122 and the arm 128.

The vapor and gas evaporated from the electrode catalyst precursor are sucked by the vacuum pump 134, and dust is filtered and collected by the bag filter 131. After that, it flows through the connecting pipe 135 to the condenser 133, where it is cooled and condensed and liquefied, and the condensed liquid is collected, and the gas is exhausted by the vacuum pump 134. In this way, the weight of the electrode catalyst precursor changes as the vapor and gas evaporates from the electrode catalyst precursor. The weight of the electrode catalyst precursor in the container body 102 at this time is measured by the load cells 112, 112, and the current moisture content of the electrode catalyst precursor is calculated from the weight and moisture content of the electrode catalyst precursor at the time of introduction and the current weight of the electrode catalyst precursor. The drying step S32 is completed when the electrode catalyst precursor in the container body 102 becomes equal to or less than a predetermined moisture content. The predetermined moisture content is preferably 3 wt%.

[Cooling process]
The cooling step S33 is a step of cooling the electrode catalyst precursor dried in the vessel body 102, and is executed by the cooling step execution means 33. Explaining this with reference to Fig. 4C together with Fig. 2 etc., the cooling step execution means 33 discharges the steam S in the jacket 106 from the heating medium discharge port 114 by the temperature indicating regulator 116. Here, the cooling step execution means 33 continues to drive the drive device 107 and the vacuum pump 134, rotates the stirring blade 104, and evacuates and reduces the pressure inside the vessel body 102, thereby continuing the stirring and mixing of the electrode catalyst precursor. At this time, the rotation speed of the stirring blade 104 is preferably 50 to 100 revolutions per minute, and the pressure during the reduction is preferably atmospheric pressure. Furthermore, the cooling process execution means 33 injects the cooling medium C from the heating medium inlet 113 into the jacket 106 using the temperature indicating regulator 116, and cools the vessel body 102 by conductive heat transfer of the cooling medium, thereby cooling the electrode catalyst precursor in the vessel body 102 to a predetermined temperature. The temperature of the cooling medium C is preferably 10 to 30° C., and the predetermined temperature is preferably a value not higher than 40° C., and more preferably selected from the range of 10 to 40° C. The cooling process is completed when the cooling process execution means 33 detects through the temperature indicating regulator 116 that the electrode catalyst precursor has reached the predetermined temperature.

[Slow oxidation process]
The gradual oxidation step S34 is a step of subjecting the electrode catalyst precursor cooled in the container body 102 to a gradual oxidation treatment, and is executed by the gradual oxidation step execution means 34. The gradual oxidation step execution means 34 discharges the cooling medium C in the jacket 106 from the heating medium outlet 114, stops the driving device 107 and the vacuum pump 134, and operates the manhole 115 to gradually return the pressure in the container body 102 to normal pressure, thereby gradually oxidizing the dried electrode catalyst precursor. In addition, when the gas G for the scraper is high-pressure air, the gradual oxidation step execution means 34 may be configured to inject the high-pressure air from the flow path of the gas G for the scraper into the rotating main shaft 122 and spray the high-pressure air from each gas ejection hole 126 to gradually return the pressure in the container body 102 to normal pressure. In addition, when an air blow nozzle is provided at the bottom of the container body 102, the gradual oxidation step execution means 34 may be configured to gradually return the pressure in the container body 102 to normal pressure by the air blow nozzle. When the gradual oxidation treatment of the electrode catalyst precursor in the container body 102 is completed, the gradual oxidation step is completed.
In addition, in the gradual oxidation step S34, when the pressure inside the container body 102 is gradually returned to normal pressure and the inside of the container body 102 is finally returned to an air atmosphere at normal pressure, a mixed gas in which nitrogen gas and oxygen gas are mixed in an arbitrary ratio to adjust the oxygen gas concentration, or a mixed gas in which nitrogen gas and air are mixed in an arbitrary ratio to adjust the oxygen gas concentration, is ejected from each gas ejection hole 126, and the oxygen gas concentration inside the container body 102 is increased over time while being controlled within a numerical range experimentally determined in advance so that the electrode catalyst precursor does not ignite during this step, and finally the oxygen concentration is made the same as that of the air.

[Removal process]
The removal step S35 is a step of removing the electrode catalyst precursor cooled in the container body 102, and is executed by the removal step execution means 35. Explaining FIG. 4D with reference to FIG. 2 and the like, the removal step execution means 35 operates and opens the removal valve 109 to remove the electrode catalyst precursor from the container body 102 through the opening 108. Since the internal structure of the container body 102 of the stirring processing device 101 is simple, and the ribbon blade 125 formed in a spiral shape is configured not to have a center shaft, it is possible to reduce the amount of remaining powder of the electrode catalyst precursor in the removal step S35. In addition, at this time, the removal step execution means 35 performs a scraper step in which gas G is injected from the passage of the gas G for the scraper into the rotating main shaft 122 and gas G is sprayed downward from each gas ejection hole 126, thereby blowing the electrode catalyst precursor attached to the inner wall of the container body 102 and the stirring blade 104 downward, and increasing the recovery rate of the electrode catalyst precursor. The removal step is completed when all of the electrode catalyst precursor inside the container body 102 has been removed.

<Electrode catalyst>
The structure of the electrode catalyst produced in this embodiment is not particularly limited, and may be a structure in which precious metal catalyst particles are supported on a conductive support (conductive carbon support, conductive metal oxide support, etc.). For example, it may be a so-called Pt catalyst, a Pt alloy catalyst (PtCo catalyst, PtNi catalyst, etc.), or a so-called core-shell catalyst having a core-shell structure.
For example, in a core-shell catalyst having a configuration in which palladium is used as a constituent element of the core portion 4 and platinum is used as a constituent element of the shell portion 5, a material containing chlorine (Cl) species such as a chloride salt of platinum (Pt) or a chloride salt of palladium (Pd) is often used as a raw material. According to the manufacturing system and manufacturing method of the electrode catalyst of this embodiment, an electrode catalyst having a reduced content of these chlorine (Cl) species can be manufactured.

An example of the structure of an electrode catalyst will be described in more detail with reference to the figures. As shown in FIG. 5, an electrode catalyst 1 having a core-shell structure includes a carrier 2 and a catalyst particle 3 supported on the carrier 2. The catalyst particle 3 includes a core portion 4 and a shell portion 5 formed so as to cover at least a portion of the core portion 4. The catalyst particle 3 has a so-called core-shell structure including the core portion 4 and the shell portion 5 formed on the core portion 4.

That is, the electrode catalyst 1 has catalyst particles 3 supported on a carrier 2, and the catalyst particles 3 have a structure in which a core portion 4 serves as a nucleus (core) and a shell portion 5 serves as a shell that covers the surface of the core portion 4. In addition, the constituent elements (chemical composition) of the core portion 4 and the constituent elements (chemical composition) of the shell portion 5 have different compositions.

To further illustrate a specific example of the core-shell structure, in FIG. 6, the electrode catalyst 1A has a catalyst particle 3a composed of a core portion 4, a shell portion 5a covering a part of the surface of the core portion 4, and a shell portion 5b covering a part of the other surface of the core portion 4. Also, in FIG. 7, the electrode catalyst 1B has a catalyst particle 3 composed of a core portion 4 and a shell portion 5 covering almost the entire surface of the core portion 4, and the shell portion 5 has a two-layer structure comprising a first shell portion 6 and a second shell portion 7. Furthermore, in FIG. 8, the electrode catalyst 1C has a catalyst particle 3a composed of a core portion 4, a shell portion 5a covering a part of the surface of the core portion 4, and a shell portion 5b covering a part of the other surface of the core portion 4, and the shell portion 5a has a two-layer structure comprising a first shell portion 6a and a second shell portion 7a, and the shell portion 5b has a two-layer structure comprising a first shell portion 6b and a second shell portion 7b.

In this embodiment, the chlorine (Cl) species refers to a chemical species containing chlorine as a constituent element. Specifically, the chemical species containing chlorine include chlorine atoms (Cl), chlorine molecules (Cl ₂ ), chloride ions (Cl ⁻ ), chlorine radicals (Cl.), polyatomic chlorine ions, and chlorine compounds (such as X—Cl, where X is a counter ion).

In this embodiment, the term "bromine (Br) species" refers to chemical species that contain bromine as a constituent element, specifically, chemical species that contain bromine include bromine atoms (Br), bromine molecules (Br ₂ ), bromide ions (Br ⁻ ), bromine radicals (Br.), polyatomic bromine ions, and bromine compounds (such as X—Br, where X is a counter ion).

<Method of manufacturing electrode catalyst>
9, the electrode catalyst manufacturing method according to this embodiment includes an electrode catalyst precursor manufacturing step S1 for manufacturing an electrode catalyst precursor, which is a raw material for an electrode catalyst, a cleaning step S2 for cleaning the electrode catalyst precursor manufactured in the electrode catalyst precursor manufacturing step S1, and a drying step S3 for drying the electrode catalyst precursor cleaned in the cleaning step S2 by an agitation processing device 101 equipped with an agitation blade 104 having a blade plate 127. Each of steps S1, S2, and S3 can be performed by the electrode catalyst precursor manufacturing device 12, the cleaning device 13, and the agitation processing device 101, respectively, of the electrode catalyst manufacturing system 10 described above.

As shown in FIG. 10, the drying step S3 includes an introduction step S31, a drying step S32, a cooling step S33, a gradual oxidation step S34, and a removal step S35. In the drying step S3, the electrode catalyst precursor washed in the washing step S1 is dried to obtain the dried electrode catalyst precursor 41. The configuration of each step S31 to S35 is as described above in the <Electrode catalyst manufacturing system> (drying device).

The examples described herein are illustrative of embodiments of the invention and should not be construed as limiting the scope of the invention.

<Production of electrode catalyst precursor (reaction process, electrode catalyst precursor production step)>
(Production Example 1)
[Preparation of liquid (stock solution) containing electrode catalyst precursor]
A Pt particle-supported carbon catalyst (hereinafter referred to as "Pt/C catalyst", manufactured by N.E. CHEMCAT, Pt support rate 50 wt %, product name: "SA50BK") was used as the electrode catalyst. First, a liquid containing its precursor was prepared.
As the carrier for this precursor, a commercially available conductive hollow carbon carrier (manufactured by Lion Corporation, trade name "Carbon ECP" (registered trademark) (Ketjen Black EC300J), specific surface area 750 to 800 m ² /g) was used.
The carrier and the water-soluble Pt salt were dispersed in water. Next, a water-soluble reducing agent was added to the dispersion containing the carrier and the water-soluble Pt salt, and the reduction reaction of the Pt component was allowed to proceed at a predetermined temperature. In this way, a liquid containing the electrode catalyst precursor used in this embodiment was prepared.

The electrode catalyst precursor powder obtained as described above was dispersed in a kettle without drying and used as the stock solution to be treated in the cleaning device.

<Production of electrode catalyst>
Example 1
[Treatment by cleaning device (cleaning step)]
The liquid containing the electrode catalyst precursor obtained in Production Example 1 was introduced into a washing device and subjected to washing treatment, thereby obtaining a cake containing the electrode catalyst precursor.

Example 1
[Treatment by drying device (drying step)]
The cake containing the electrode catalyst precursor obtained after the treatment by the washing device was introduced into the stirring treatment device 101 as a drying device, and the drying step S3 was carried out.
In this Example 1, since the cake containing the electrode catalyst precursor is dried using the stirring treatment device 101 having a stirring mechanism, there is no need to crush the cake containing the electrode catalyst precursor (coarsely crushing the cake before introducing it into the tray vacuum dryer) which is performed in Comparative Example 1 described later. That is, the crushing step in Comparative Example 1 described later is not necessary.
The processing time for each step in the agitation processing device 101 is shown in Table 1.
In the introduction step S31, the capacity of the agitation device 101 was selected based on the powder surface height in the container body 102 of the agitation device 101 when 52 kg of cake was charged, and an agitation device 101 was adopted in which the effective capacity of the container body 102 was 100 L and the blade plate 127 had discontinuous inclined paddle blades.
First, in the introduction step S31, 52 kg of cake having a moisture content of about 82 % was charged into the container body 102 to charge the cake.
Thereafter, the drying step S32, the cooling step S33, and the gradual oxidation step S34 were carried out in this order, and the cake was taken out in the removal step S35, and the time required to obtain an electrode catalyst with a moisture content of 3 wt % or less was measured.
Furthermore, in order to confirm whether or not "friction" caused by the stirring and drying would have any effect on the product, in the cooling step S33, the stirring blade 104 was rotated while the cooling medium C was injected into the jacket 106 from the heating medium injection port 113, and a stirring test was performed with the electrode catalyst precursor while cooling.

(Comparative Example 1)
The cake containing the electrode catalyst precursor obtained after the treatment with the washing device was subjected to a drying step using a dedicated crusher, a tray vacuum dryer, and a hammer mill.
First, the cake was crushed in a dedicated crusher in a crushing process to obtain 52 kg of an electrode catalyst precursor with a moisture content of about 80 to 82%.
In this crushing step, the cake is removed from the cleaning device and crushed (coarsely crushing the cake before introduction into the tray vacuum dryer) containing the electrode catalyst precursor. Unlike the stirring treatment device 101 in Example 1, the tray vacuum dryer used in this Comparative Example 1 is not equipped with a stirring mechanism, so a crusher is used to roughly crush the cake before introduction into the tray vacuum dryer, and the crushed cake must be distributed approximately evenly on the shelves.
In the subsequent introduction step, this electrode catalyst precursor was arranged in a cake arrangement onto 20 pads measuring 600 mm in width, 780 mm in length, and 20 mm in height. The pads on which the electrode catalyst precursor was arranged were placed in a shelf vacuum dryer, the door was closed, and a drying step in which the electrode catalyst precursor was dried under reduced pressure and a cooling step in which the electrode catalyst precursor was cooled under reduced pressure were performed.
After the cooling step, a gradual oxidation step was carried out by slowly opening the door, and in the subsequent removal step, the pad was removed from the tray vacuum dryer to remove the electrode catalyst precursor.
Thereafter, the extracted electrode catalyst precursor was subjected to a pulverization step in which it was pulverized with a hammer mill, and the time required to obtain an electrode catalyst having a water content of 3 wt % or less was measured.
Unlike the stirring treatment device 101 of Example 1, the tray vacuum dryer used in this Comparative Example 1 is not equipped with a stirring mechanism, and therefore it is necessary to pulverize the lumps of electrode catalyst precursor powder using a hammer mill. In addition, it becomes necessary to remove the lumps of electrode catalyst precursor powder from the tray vacuum dryer before pulverization with the hammer mill.

<Evaluation Results>
As shown in Table 1, in Example 1, there was no need to arrange the electrode catalyst precursor in the introduction step S31, and the electrode catalyst precursor was simply charged into the container body 102, so that the time required was reduced from 2 hours in Comparative Example 1 to 0.4 hours.
In Example 1, the drying speed in the drying step S32 and the cooling step S33 was improved compared to the tray vacuum dryer due to the high mixing capacity and heat transfer from the jacket 106, and the drying time was reduced from 24 hours required in Comparative Example 1 to 6.3 hours.
Here, it was confirmed that the obtained electrode catalyst was almost comparable to that of Comparative Example 1, and that the "friction" caused by the stirring and drying had almost no effect on the product quality. Furthermore, in Example 1, no reduction in time was confirmed in the gradual oxidation step S34 and the extraction step S35 compared to Comparative Example 1, while in Example 1, the crushing step and the pulverization step could be omitted.

Therefore, according to the manufacturing system and manufacturing method of the electrode catalyst of this embodiment, the time required for processing by the drying device 14 (drying step S3) can be significantly reduced to about 1/4. Furthermore, since the stirring processing device 101 as the drying device 14 of this embodiment can automatically perform the drying step S32, the cooling step S33, the gradual oxidation step S34, and the removal step S35, the labor required can be significantly reduced, and it is possible to provide a manufacturing method and manufacturing system for electrode catalysts that involves as little manual work as possible.

<Electrode catalyst manufacturing system>
11 is a block diagram showing an outline of an electrode catalyst manufacturing system according to the second embodiment. In addition to the electrode catalyst precursor manufacturing apparatus 12, cleaning apparatus 13, and drying apparatus 14 described in the first embodiment, the electrode catalyst manufacturing system 150 further includes an analyzer 151 for analyzing the physical properties of the electrode catalyst 1 after drying and a wet product after preparing a catalyst cake, and a reactor 152 for mixing ion-exchanged water with the electrode catalyst 1 after drying to reslurry it.

Conventionally, concerns about the ignition and loss of powdered electrode catalysts have been an issue when packaging powdered electrode catalysts for shipment and when weighing them when used by customers. As a measure against ignition and loss of electrode catalysts and in future packaging and delivery forms, it is expected that electrode catalyst powders will be supplied as wet products in which they are wetted with pure water, and demand is expected to increase in the future. However, for example, if the weight ratio of electrode catalyst to water is 1:4, the wet product will not become solid but will become liquid. Electrode catalysts are expensive and need to be recovered as much as possible, but the wet product would stick to the device or the container that holds the electrode catalyst, and would dry out and adhere to the inner walls of the container. A method has also been devised in which the electrode catalyst:water is extracted as a wet product with a desired weight ratio in the drying step S32 of the first embodiment, but in this case, the wet product is in a state that has not undergone the gradual oxidation step S34, and there is a risk that the oxidation state of the catalyst particle surface of the electrode catalyst cannot be made sufficiently stable in the atmosphere, and thus the electrode catalyst may have a different initial activity for the hydrogen oxidation reaction and the oxygen reduction reaction. In this case, since the electrode catalyst precursor is simply washed and filtered in the cleaning step S2, there is a possibility that the uniformity of the moisture content of the wet product may become uneven. For these reasons, supplying the wet product is difficult to handle and recover both at the manufacturer and the customer.

Therefore, in this embodiment, the electrode catalyst precursor after cleaning is dried to make the oxidation state of the catalyst particle surface of the electrode catalyst sufficiently stable in the atmosphere. In addition, ion exchange water is mixed with the electrode catalyst 1 after drying, and the water content of the slurry containing the electrode catalyst is made uniform, and then it is dried to a level where it can be made into a solid (pellet-like, cake-like). As a result, the water content of the WET product is adjusted to the target numerical range to prepare multiple solid catalyst cakes, and by supplying the powdered catalyst with a desired weight ratio, the risk of ignition and loss is reliably prevented, and the handling and recovery are improved at both the manufacturer and the customer destination. In addition, for the solid catalyst cake, during the catalyst synthesis process, the surface of the catalyst carrier is subjected to various chemical actions from each reagent used in the synthesis, and the products, by-products, and impurities generated in each synthesis reaction. As a result, the type, total amount, and amount per unit area of the surface functional groups of the catalyst carrier differ. As a result, the affinity (wettability) of the catalyst to water changes depending on the type of catalyst (type of carrier) and the type of synthesis reaction process used. Therefore, the moisture content (moisture content range) that will result in a solid that is easy to handle and recover must be determined experimentally in advance for each catalyst.

(Analysis equipment)
The analyzer 151 analyzes the physical properties of the electrode catalyst 1 obtained through the drying step S3 of the first embodiment. The analyzer 151 includes a first physical property analysis execution means 153 that executes a first physical property analysis step S36 of the electrode catalyst 1 taken out in the taking-out step S35 of the first embodiment. In this first physical property analysis step S36, it is preferable to analyze at least the catalyst loading amount, water content (wt%), and catalyst particle size of the electrode catalyst 1. Note that in this embodiment, a method is adopted in which a portion of the powder of the electrode catalyst 1 taken out in the taking-out step S35 is sampled and the physical properties are analyzed by the analyzer 151, but other analysis methods may be used.

(Reactor)
The reactor 152 reslurries the electrode catalyst 1 dried in the drying device 14 after the first physical property analysis step S36. In this embodiment, the electrode catalyst 1 is reslurried using the reactor 152, and while this requires one more piece of equipment, it more quickly and reliably reslurries the electrode catalyst 1. The reactor 152 includes a reslurry step executing means 154 that executes a reslurry step S40 for reslurrying the electrode catalyst 1 removed in the removal step S35. As a method for reslurrying in the reslurry step S40, a reslurry method using a reactor equipped with a stirring device, for example a kettle equipped with a stirrer, can be adopted.

As shown in the block diagram of FIG. 11 and the flowchart of FIG. 12, the reslurry step execution means 154 includes an introduction step execution means 156, a mixing step execution means 157, and an extraction step execution means 158, which respectively execute the introduction step S41, the mixing step S42, and the extraction step S43. In this embodiment, in order to keep the oxidation state of the catalyst particle surface of the electrode catalyst used stable in the atmosphere, each step S41 to S43 is performed at room temperature, at atmospheric pressure, and in the atmosphere, rather than in a special gas atmosphere such as nitrogen. Each step S41 to S43 is described below.

[Introduction process]
The introduction step S41 is a step of introducing the electrode catalyst 1 dried in the drying device 14 and ion-exchanged water for mixing into the reactor 152, and is executed by the introduction step execution means 156. The method of introducing the electrode catalyst 1 and the ion-exchanged water may be manual introduction using a funnel or the like, as in the introduction step S31, or the electrode catalyst 1 and the ion-exchanged water may be directly introduced without human intervention by providing the reactor 152 with a pipe or a belt conveyor for transporting the electrode catalyst 1 and the ion-exchanged water.

As for the ion-exchanged water, pure water can be used, and it is preferable to use "ultrapure water.""Ultrapurewater" is defined as:
R = 1 / ρ (1)
The resistivity R (the reciprocal of the electrical conductivity measured by the JIS standard test method (JIS K0552)) represented by the formula is 3.0 MΩ cm or more. In the above formula (1), R represents resistivity, and ρ represents electrical conductivity measured by the JIS standard test method (JIS K0552). The "ultrapure water" preferably has a water quality equivalent to or higher than "A3" as specified in JIS K0557 "Water used for testing water and wastewater", but is not particularly limited as long as it has an electrical conductivity that satisfies the relationship represented by this formula (1). For example, ultrapure water produced using an ultrapure water production apparatus such as "Milli Q series" (manufactured by Merck Ltd.) or "Elix UV series" (manufactured by Nihon Millipore K.K.) may be used as the "ultrapure water". The ion-exchanged water does not necessarily have to be pure water, and for example, ion-exchanged water having a pH of 6 to 8 and an electrical conductivity ρi of less than 10 μS/cm as measured according to the JIS standard test method (JIS K0522) can be used.

The weight ratio of the electrode catalyst 1 and the ion-exchanged water introduced in the introduction step S41 is preferably such that the mixture of the electrode catalyst 1 and the ion-exchanged water becomes a liquid slurry. For example, the weight ratio of the electrode catalyst:ion-exchanged water is experimentally determined to be optimal depending on the catalyst type from within a range of 1:2 to 1:3.5. In this embodiment, the amount of ion-exchanged water to be introduced is calculated and determined from the results of the physical property analysis of the electrode catalyst 1, such as the catalyst loading amount and water content, and the amount of the electrode catalyst 1 to be introduced. The amount of the electrode catalyst 1 to be introduced may be measured manually, or the weight of the electrode catalyst 1 may be measured by the load cells 112, 112 at the start and end of the removal step S35 in the first embodiment, and the amount of the electrode catalyst 1 may be calculated using the results.

[Mixing process]
The mixing step S42 is a step of mixing the introduced electrode catalyst 1 and ion-exchanged water in the reactor 152, and is executed by the mixing step execution means 157. The mixing step execution means 157 drives the agitator of the reactor 152 to agitate and mix the electrode catalyst 1 and ion-exchanged water at room temperature and atmospheric pressure. In this embodiment, the ratio of the electrode catalyst 1 and the ion-exchanged water is such that the mixture becomes a liquid slurry, so that the electrode catalyst 1 is not likely to ignite or disappear during mixing even at room temperature and atmospheric pressure, and the mixture can be agitated and mixed more uniformly. The mixing step S42 is completed when the electrode catalyst 1 and the ion-exchanged water are mixed uniformly and a slurry 159 containing the electrode catalyst is prepared. The driving time and rotation speed of the agitator will not be described in detail here because they vary depending on the capacity and type of the reactor 152, the amount of the introduced electrode catalyst 1 and ion-exchanged water, etc.

[Removal process]
The removal step S43 is a step of removing the electrode catalyst-containing slurry 159 prepared in the reactor 152, and is performed by the removal step execution means 158. Thereafter, the removed electrode catalyst-containing slurry 159 is introduced again into the drying device 14. Therefore, when the electrode catalyst-containing slurry 159 is introduced into the drying device 14 by manual work, the electrode catalyst-containing slurry 159 may be temporarily removed into another container or the like. When the electrode catalyst-containing slurry 159 is directly introduced into the drying device 14 without manual work, a pipe or the like may be connected to the drying device 14, and the electrode catalyst-containing slurry 159 may be transferred from the reactor 152 to the drying device 14 through the pipe or the like. The removal step S43 is completed when all of the electrode catalyst-containing slurry 159 in the reactor 152 is removed. The removal step execution means 158 differs depending on the type of the reactor 152, and will not be described in detail here.

(Drying device)
The drying device 14 dries the slurry 159 containing the electrode catalyst reslurried in the reslurry step S40 with an agitation processing device 101 equipped with an agitation blade 104 to prepare a plurality of solid catalyst cakes. The drying device 14 used in this step may be the drying device 14 used in the drying step S3 in the first embodiment, or may be another drying device 14. The structure of the agitation processing device 101 as a drying device is similar to that in the first embodiment, and therefore a description thereof will be omitted.

The catalyst cake preparation step S50 for preparing a solid catalyst cake includes, like the drying step S3 in the first embodiment, an introduction step S31', a drying step S32', a cooling step S33', a gradual oxidation step S34' for subjecting the cooled wet product to a gradual oxidation treatment, and an unloading step S35' for unloading the wet product that has been subjected to the gradual oxidation treatment. The operating conditions of each step S31' to S35' are the same as those of each step S31 to S35 in the drying step S3 in the first embodiment, and therefore the main actions of each step S31' to S35' are the same as those of each step S31 to S35 in the drying step S3 in the first embodiment.

In the drying step S32', steam and gas evaporate from the slurry 159 in the container body 102, causing the weight of the slurry 159 to change. The weight of the slurry 159 in the container body 102 at this time is measured by the load cells 112, 112, and the current moisture content of the slurry 159 is calculated from the weight of the slurry 159 at the time of introduction, the weight ratio of the electrode catalyst 1 to the ion-exchanged water determined in the introduction step S41, and the current weight of the slurry 159. The drying step S32' is completed when the slurry 159 in the container body 102 becomes a solid (pellet-like, cake-like) wet product with a predetermined moisture content or less. In this way, the slurry 159 with a uniform moisture content is dried to prepare a wet product of the catalyst cake, thereby making the moisture content of the wet product uniform. Here, the predetermined moisture content is preferably less than 80 wt%, so that the wet product does not stick to the container body 102 or the stirring blade 104.

In the gradual oxidation step S34', as in the drying step S3, the cooling medium C in the jacket 106 is discharged from the heating medium outlet 114, the drive unit 107 and vacuum pump 134 are stopped, and the supply valve 115 is operated to gradually return the pressure in the container body 102 to normal pressure, thereby gradually oxidizing the WET catalyst cake. Therefore, compared to conventional box-type shelf vacuum dryers, the operation time can be significantly shortened and automated. Furthermore, since the gradual oxidation step S34' can also be automated, the gradual oxidation step can be carried out more reliably. The gradual oxidation step is completed when the gradual oxidation treatment of the WET catalyst cake in the container body 102 is completed.

(Analysis equipment)
The analysis device 151 performs a physical property analysis on the wet product obtained through the catalyst cake preparation step S50. The analysis device 151 includes a second physical property analysis execution means 161 that executes a second physical property analysis step S60 of the wet product taken out in the take-out step S35'. In this second physical property analysis step S60, it is preferable to analyze at least the water content (wt%) of the wet product. Note that, in this embodiment, a method is adopted in which a portion of the wet product taken out in the take-out step S35' is sampled and the physical properties are analyzed by the analysis device 151, but other analysis methods may be used.

[First storage step]
The first accommodation step is a step of accommodating the wet catalyst cake taken out in the take-out step S35' in a container or bag. The container or bag used in this first accommodation step is made of plastic and has an antistatic agent applied to the inside. After the second physical property analysis step is performed, the wet product taken out in the take-out step S35' is accommodated in this plastic packaging container or packaging bag. This first accommodation step is performed in the atmosphere, and the wet product is accommodated in the packaging container or packaging bag while acclimatizing to the atmosphere. In this step, the take-out step S35' may be performed such that a plastic packaging container or packaging bag is placed below the opening 108 in advance, and the wet product is dropped from inside the container body 102 into the packaging container or packaging bag to be directly accommodated, or the take-out step S35' may be performed such that the wet product is once taken out and then accommodated in the plastic packaging container or packaging bag.

Then, the plastic packaging container or packaging bag containing the wet catalyst cake is further placed in a container. The container used here is a stainless steel UN can (a container that displays a "UN inspection certificate (UN mark)" that has passed the container performance test conducted by the Japan Ship Equipment Inspection Association in accordance with international standards: a dangerous goods transport container), with an antistatic coating on the inside. This UN can is preferably made of SUS316, and is preferably capable of containing substances classified as UN number 3178, product name: other flammable substances, and UN classification: 4.1, with a container class of 2 or 3. After the second placement process is completed, this UN can is transported and supplied to the customer.

[Second storage step]
In the second storage step, as another embodiment, the UN can is used instead of the plastic packaging container or packaging bag in the first storage step. In this case, the UN can used is configured to be able to hermetically store the wet product.

Although the present invention has been described above based on the embodiment and examples, the present invention can be implemented in various modified forms. In particular, the electrode catalyst precursor manufacturing apparatus 12 (reaction process, electrode catalyst precursor manufacturing apparatus step S1) and the cleaning apparatus 13 (cleaning step S2) are not particularly limited, and various modified forms can be adopted.

The reslurry step may also be performed in the drying device 14 without using the reactor 152. In this case, the removal step S35 of the drying step S3 and the removal step S43 of the reslurry step can be omitted, which allows for a significant reduction in work time. In addition, since the drying step, the reslurry step S40, and the catalyst cake preparation step S50 can be performed using only one pot of the drying device 14, there is no need to transport the electrode catalyst 1 or the slurry 159 containing the electrode catalyst, so the drying step S3, the reslurry step S40, and the catalyst cake preparation step S50 can be automated without manual work, allowing each step to be performed more reliably.

When the reslurry step S50 is performed in the drying device 14, the process proceeds to the physical property analysis process after the completion of the gradual oxidation process S34 of the drying step S3, where a portion of the electrode catalyst 1 in the container body 102 is extracted, and the physical property analysis of this electrode catalyst 1 is performed by the physical property analysis execution means 153 in the same manner as described above. When the physical property analysis is completed, the process proceeds to the introduction process S41 of the reslurry step S40.

In the introduction step S41, the ion-exchanged water to be mixed is introduced into the container body 102 by the introduction step execution means 156. In this embodiment, an ion-exchanged water supply line (not shown), such as a pipe through which the ion-exchanged water is transported, is provided in the drying device 14, and the ion-exchanged water is directly introduced through this ion-exchanged water supply line without human intervention. Note that the method of introducing the ion-exchanged water may be introduced manually using a funnel or the like, similar to the introduction step S31.

In the mixing step S42, the driving device 107 is driven by the mixing step execution means 157, and the stirring blade 104 is rotated to stir and mix the electrode catalyst 1 and the ion-exchanged water at room temperature and atmospheric pressure. When the electrode catalyst 1 and the ion-exchanged water are mixed uniformly and a slurry 159 containing the electrode catalyst is prepared, the mixing step S42 is completed and the process moves to the drying step S32' of the catalyst cake preparation step. The subsequent steps are the same as when the reactor 152 is used.

The structure of the drying device 14 is not limited to that shown in FIG. 2, and the structure of the container body 102 is not limited to that shown in FIGS. 2 to 4. Various modified examples can be used as long as they provide similar effects in each of steps S31 to S35 of the drying step S3 according to this embodiment.

REFERENCE SIGNS LIST 1 Electrode catalyst 2 Support 3 Catalyst particle 4 Core portion 5 Shell portion
10. Electrode catalyst manufacturing system
12. Electrode catalyst precursor manufacturing equipment
13 Cleaning equipment
14 Drying equipment
101 Mixing treatment device
102 Container body
104 Stirring blade
122 Rotating shaft
127 Slat (inclined paddle blade)
128 Arm (rotor support)
129 Gas Vents
152 Reactor S1 Electrode catalyst precursor production step S2 Cleaning step S3 Drying step S31 Introduction step S32 Drying step S33 Cooling step S34 Gradual oxidation step S35 Removal step S36 First physical property analysis step (first analysis step)
S40 Reslurry step S50 Catalyst cake preparation step S60 Second physical property analysis step (second analysis step)

The electrode catalyst manufacturing system and manufacturing method of the present invention eliminates the need for workers to transfer electrode catalyst precursors and shortens the drying time of the electrode catalyst precursors, significantly reducing the effort and time required to manufacture electrode catalysts with low halogen content, particularly low chlorine content.

The present invention is therefore a manufacturing system and method for electrode catalysts that can be applied not only to the electrical equipment industry, such as fuel cells, fuel cell vehicles, and portable mobile devices, but also to ENE-FARM and cogeneration systems, and contributes to the development of the energy industry and environmental technologies.

Claims (10)

an electrode catalyst precursor manufacturing apparatus for manufacturing an electrode catalyst precursor, which is a raw material for an electrode catalyst;
a cleaning device for cleaning the electrode catalyst precursor;
a drying device that dries the electrode catalyst precursor washed by the washing device using an agitation treatment device equipped with an agitation blade having discontinuous inclined paddle blades,
The drying device is
an introduction step of introducing the electrode catalyst precursor into a vessel body of the stirring treatment device;
a drying step of heating the container body while reducing the pressure, and stirring and mixing the electrode catalyst precursor in the container body with the stirring blade, thereby drying the electrode catalyst precursor;
a cooling step of cooling the electrode catalyst precursor by cooling and reducing the pressure of the container body and stirring and mixing the electrode catalyst precursor in the container body with the stirring blade;
a gradual oxidation step of supplying air into the container body and subjecting the electrode catalyst precursor to a gradual oxidation treatment;
and removing the electrode catalyst precursor from the container body. the stirring blade includes a main shaft that is rotated by a drive device to rotate the stirring blade, the inclined paddle blade that stirs and mixes the electrode catalyst precursor in the container body, and a rotor support that connects the main shaft and the inclined paddle blade,
The rotor shaft and the rotor support are formed in a hollow tubular shape,
The rotor support has a gas outlet hole on the lower side of the tip,
2. The system for manufacturing an electrode catalyst according to claim 1, wherein the rotating shaft is connected to a gas flow path. an electrode catalyst precursor producing step of producing an electrode catalyst precursor which is a raw material for the electrode catalyst;
a washing step of washing the electrode catalyst precursor;
a drying step of drying the electrode catalyst precursor after the washing step by using an agitation treatment device equipped with an agitation blade having discontinuous inclined paddle blades,
The drying step comprises:
a drying step of drying the electrode catalyst precursor by heating and reducing the pressure of a container body of the stirring treatment device and stirring and mixing the electrode catalyst precursor in the container body with the stirring blade;
a cooling step of cooling the electrode catalyst precursor by cooling and reducing the pressure of the container body and stirring and mixing the electrode catalyst precursor in the container body with the stirring blade;
and a gradual oxidation step of supplying air into the container body and subjecting the electrode catalyst precursor to a gradual oxidation treatment. The method further includes a removal step of removing the electrode catalyst precursor from the container body,
4. The method for producing an electrode catalyst according to claim 3, wherein the removing step includes a scraper step of ejecting gas downward from gas ejection holes provided at the tip of a rotor support supporting the inclined paddle blades. a first analysis step of performing a physical property analysis of the electrode catalyst precursor obtained through the drying step;
a reslurry step of mixing the electrode catalyst precursor obtained through the drying step with ion-exchanged water to prepare a slurry again;
A catalyst cake preparation step of drying the slurry obtained through the reslurry step to prepare a plurality of solid catalyst cakes having a moisture content adjusted to a predetermined range;
The method for producing an electrode catalyst according to claim 3 , further comprising: The method for producing an electrode catalyst according to claim 5, wherein the stirring-type drying device used in the catalyst cake preparation step is the stirring treatment device. The method for producing an electrode catalyst according to claim 5 or 6, in which a reactor equipped with a stirring device is used in the reslurry step. The method for producing an electrode catalyst according to claim 7, wherein the reactor is the stirring treatment device. The method for producing an electrode catalyst according to any one of claims 5 to 8, wherein the water content of the catalyst cake is less than 80 wt%. The method for producing an electrode catalyst according to any one of claims 5 to 9, further comprising a second analysis step of measuring the water content of the catalyst cake obtained through the catalyst cake preparation step.

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