JP4889217B2 - Manufacturing method of fuel reformer - Google Patents

Description

The present invention relates to a fuel reforming equipment manufacturing method of accommodating a fuel reformer for generating hydrogen gas from a variety of fuels, for example in a fuel cell system.

  In recent years, fuel cell systems have been in the limelight as next-generation power systems that produce electric energy efficiently and cleanly. In the cogeneration power generation system market, which is already represented by the automobile market and household fuel cell power generation systems. In the field, field tests for practical application aiming at low cost are actively conducted.

  More recently, the fuel cell system has been reduced in size and is being studied for use as a power source for portable devices such as mobile phones, PDAs (Personal Digital Assistants), notebook computers, digital video cameras, and digital still cameras.

  In general, a fuel cell uses, for example, hydrocarbon gas such as methane or natural gas (CNG) or alcohol such as methanol or ethanol as fuel, and is converted to hydrogen gas or other gas by a fuel reformer using a fuel reformer. Then, the hydrogen gas is supplied to a power generation device called a power generation cell to generate power.

  The reforming of fuel by the fuel reformer here refers to a process of generating hydrogen gas by a catalytic reaction.

For example, when methanol is used as the fuel, there are several reactions for reforming the fuel. For example, in the steam reforming reaction shown in the following chemical reaction formula (1) (in formula (1), steam is added to methanol. This is a process for generating hydrogen gas (H ₂ ) by combining them with a reaction to reform hydrogen and carbon dioxide. Note that a very small amount of product gas (mainly CO ₂ ) other than hydrogen produced by this reforming reaction is usually discharged into the atmosphere.

CH ₃ OH + H ₂ O → 3H ₂ + CO ₂ (1)
Since such a steam reforming reaction is an endothermic reaction, it is necessary to maintain the reaction temperature by heating from the outside with a heater or the like. Therefore, in order to reform the fuel in the fuel reformer, for example, methanol was used as the fuel in order to prevent the steam reforming activity of the catalyst from being lowered and to maintain a high concentration of generated hydrogen gas. In some cases, a temperature of about 200 to 500 ° C. is required, and in the case of using methane gas, a high temperature of about 300 to 800 ° C. is required.

  For example, in the partial oxidation reforming reaction as shown in the following chemical reaction formula (2), a reforming temperature of about 400 to 600 ° C. is required.

CH ₃ OH + 1 / 2O ₂ + 2N ₂ → 2H ₂ + CO ₂ + 2N ₂ (2)
Therefore, in a cogeneration power generation system typified by a household fuel cell system, since this system itself is large, the outer wall of the fuel reformer storage container is made into a double structure to form a vacuum container, or 2 By filling a heat insulating material between the inner and outer walls having a heavy structure, the heat inside the fuel reformer is prevented from being conducted to the outside and the temperature of the fuel reformer is lowered. Therefore, when a fuel reformer is used as a fuel reformer storage container, the fuel reformer can be directly joined and fixed to the inner wall of the double structure of the fuel reformer storage container. is there.
JP 2003-2602 A

  In recent years, fuel cell systems for portable devices have been required to be reduced in size and height for storage in portable devices. However, the conventional structure of the outer wall of the fuel reformer storage container having a double structure cannot be employed in a fuel cell system for portable devices because the entire fuel cell system becomes complicated and large. . Therefore, in a fuel cell system for portable equipment, when reforming fuel in the fuel reformer by evacuating the inside of the container for housing the fuel reformer composed of a base body having a cavity and a lid. It has been proposed to provide a fuel cell system that cuts off heat generated to the outside and reduces power generation loss.

  In order to use such a fuel cell system stably and safely for a long period of time, the fuel reformer storage container is sealed with the fuel reformer stored in the vacuum state inside the fuel reformer storage container. It is necessary to keep it not only immediately but also for a long time thereafter. However, after sealing the inside of the fuel reformer storage container with the lid, the surface of each component in the fuel reformer storage container such as the inner surface of the fuel reformer storage container or the surface of the fuel reformer itself The adsorbed gas may be discharged as outgas into the fuel reformer storage container with the influence of temperature during fuel reforming and the passage of time.

  In that case, since the degree of vacuum inside the fuel reformer storage container decreases, the amount of heat generated when reforming the fuel in the fuel reformer increases to the outside. As a result, the fuel reformer storage container becomes hot due to the heat, and there is a risk of destroying other components in the portable device.

  In the case where the fuel reforming reaction is an endothermic reaction such as the steam reforming reaction of the chemical reaction formula (1), the fuel reformer is heated with a heater or the like in order to reform the fuel with the fuel reformer. Although it is necessary to maintain the reaction temperature at a constant temperature, the heat of the fuel reformer is conducted to the fuel reformer storage container as described above, so that the temperature of the fuel reformer decreases. It becomes easy to do.

  Therefore, in order to maintain the reaction temperature, it is necessary to increase the heat generation amount of the heater. However, if the heat generation amount of the heater is increased, the electricity used for heating the heater in the total electric capacity generated by the power generation cells of the fuel cell. As a result, the capacity increases, and as a result, the power generation loss of the entire fuel cell system increases.

The present invention has been completed in view of the problems in the prior art, and its object is capable to maintain good vacuum in the fuel reformer accommodating container, have low power loss It is to provide a method for producing a fuel reformer.

A method for producing a fuel reformer of the present invention includes a fuel reformer that generates a reformed gas containing hydrogen gas from a fuel, a base having a cavity in which the fuel reformer is accommodated, and an upper surface of the base A lid attached to cover the cavity, a discharge pipe communicating the inside and outside of the cavity to discharge the reformed gas from the fuel reformer, and the fuel to the fuel reformer And a gas adsorbent housed in the cavity, and the internal pressure of the cavity is 10 ² Pa or less . A manufacturing method is characterized by comprising a step of housing the gas adsorbent in the cavity under a pressure of 10 ² Pa or less and joining the base and the lid .

In the fuel reformer manufacturing method of the present invention, preferably, the lid is made of a metal material having a thermal conductivity of 120 W / mK or less.

In the method for producing a fuel reforming apparatus of the present invention, preferably, the lid and the base are joined by any one of a projection method, a seam welder method, an electron beam method, and a laser beam method.

The fuel reformer manufacturing method of the present invention includes a fuel reformer that generates a reformed gas containing hydrogen gas from a fuel, a base body having a cavity in which the fuel reformer is housed, and a cavity formed on the upper surface of the base body. A lid that is attached to cover the inside of the cavity, a discharge pipe that communicates the inside and outside of the cavity to discharge the reformed gas from the fuel reformer, and inside and outside of the cavity to supply fuel to the fuel reformer a supply tube for communicating the door, a manufacturing method of a fuel reforming apparatus comprising a gas adsorbent housed in the cavity, the internal pressure of the cavity since it was 10 2 ^Pa or less, the cavity in the lid After sealing the gas, the gas adsorbed on the surface of each part in the cavity, such as the inside of the fuel reformer and the surface of the fuel reformer itself, is affected by the temperature during fuel reforming and the fuel over time. Released as outgas inside reformer However, since this gas can be satisfactorily adsorbed by the gas adsorbent, the vacuum state inside the fuel reformer is not only immediately after housing and sealing the fuel reformer in the fuel reformer. It can be kept for a long time after that.

In the method for manufacturing a fuel reforming apparatus of the present invention, the lid is made of a metal material having a thermal conductivity of 120 W / mK or less, so that heat from the fuel reformer is prevented from being transmitted to the lid, and the lid It is possible to effectively prevent the surface temperature from rising. Therefore, it is possible to effectively prevent other components in the portable device from being destroyed, and the fuel cell system can be used stably and safely for a long time.

  Further, if the base body and the lid body are joined by the welding method, only the joint portion between the base body and the lid body and the vicinity thereof are heated, and the heat is transferred from the joint portion between the base body and the lid body through the lid body. Can be effectively prevented from being transmitted to the gas adsorbent and activating the gas adsorbent. Therefore, it is possible to effectively prevent the gas adsorbing material from adsorbing the surrounding gas when the lid is attached and the adsorption characteristics of the gas adsorbing material to approach saturation and the activation force to decrease.

The fuel reforming device manufacturing method of the present invention is obtained by joining the lid body and the base body by any of the projection method, seam welder method, electron beam method, and laser beam method. Only the vicinity thereof is heated, and it is possible to more effectively suppress activation of the gas adsorbent by transferring heat from the joint portion between the base and the lid to the gas adsorbent through the lid. Therefore, it is possible to more effectively prevent the gas adsorbing material from adsorbing the surrounding gas when the lid is attached and the adsorption characteristics of the gas adsorbing material to approach saturation and the activation force to decrease.

Since the method for producing the fuel reforming apparatus of the present invention includes the step of housing the gas adsorbent in the cavity under an atmospheric pressure of 10 ² Pa or less and joining the base and the lid, By increasing the degree of vacuum around the surrounding area and reducing the activation power of the gas adsorbent, it is effective that the adsorption characteristics approach saturation due to self-activation caused by slight heat during bonding of the base and the lid. Can be prevented.

Embodiments of a method for manufacturing a fuel reformer of the present invention will be described in detail below.

FIG. 1 is a cross-sectional view showing an example of an embodiment of a fuel reformer manufactured by the method for manufacturing a fuel reformer of the present invention. In this figure, 1 is a base, 2 is an external lead terminal as wiring for supplying power to the fuel reformer, 12 is a lead terminal to which a gas adsorbent is fixed, 3 is a bonding wire, 4 is a lid, 5a is a supply pipe for supplying fuel to the fuel reformer, 5b is a discharge pipe for discharging the reformed gas from the fuel reformer, 7 is an electrode, 8 is an external lead terminal 2 in the through-hole of the base 1 An insulating sealing material for sealing and fixing while insulating, 9 is a fuel reformer, and 10 is a gas adsorbing material. The fuel modification is mainly performed by the base body 1, the cover body 4, the supply pipe 5a and the discharge pipe 5b. A fuel reformer storage container for storing the mass device 9 is constructed. The fuel reformer 9 and the gas adsorbent 10 are stored in the fuel reformer storage container, and the cavity of the base 1 is hermetically sealed by the lid 4. It becomes the fuel reformer 11 by sealing to.

Both the base body 1 and the lid body 4 in the present invention have a role as a container for storing the fuel reformer 9. These include, for example, Fe-based alloys such as SUS, Fe—Ni—Co alloy, and Fe—Ni alloy, metal materials such as oxygen-free copper, aluminum oxide (Al ₂ O ₃ ) sintered body, mullite (3Al ₂ Ceramic materials such as O ₃ .2SiO ₂ ) sintered body, silicon carbide (SiC) sintered body, aluminum nitride (AlN) sintered body, silicon nitride (Si ₃ N ₄ ) sintered body, and glass ceramics In addition, it is made of a highly heat-resistant resin material such as polyimide.

The glass ceramics applicable to the substrate 1 and the lid 4 are composed of a glass component and a filler component. As the glass component, for example, SiO ₂ —B ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —MO system (where M is Ca, Sr, Mg, Ba or Zn), SiO ₂ —Al ₂ O ₃ —M ¹ O—M ² O system (where M ¹ and M ² are the same or different, and Ca, Sr, Mg, Ba or Zn), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ¹ O—M ² O system (where M ¹ and M ² are the same as above), SiO ₂ —B ₂ O ₃ — M ³ ₂ O system (where M ³ represents Li, Na or K), SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ³ ₂ O system (where M ³ is the same as above) , Pb glass, Bi glass and the like.

Examples of the filler component include a composite oxide of Al ₂ O ₃ , SiO ₂ , ZrO ₂ and an alkaline earth metal oxide, a composite oxide of TiO ₂ and an alkaline earth metal oxide, Al ₂ O _3. And composite oxides containing at least one selected from SiO ₂ (for example, spinel, mullite, cordierite) and the like.

  On the other hand, when the base body 1 and the lid 4 are formed of a dense aluminum oxide sintered body having a relative density of 95% or more, for example, first, rare earth oxide powder or aluminum oxide powder is added to the aluminum oxide powder. A raw material powder of an aluminum oxide sintered body is prepared by adding and mixing a sintering aid such as the above. Next, an organic binder and a dispersion medium are added to this raw material powder, mixed to form a paste, and this paste is green by a doctor blade method, or an organic binder is added to the raw material powder, and press forming, rolling forming, etc. A sheet is produced. Then, after aligning and laminating and pressing a predetermined number of sheet-shaped molded bodies, the laminated body is fired at a firing maximum temperature of 1200 to 1500 ° C. in a non-oxidizing atmosphere, for example. A base body 1 and a lid 4 made of the product are obtained. The base 1 and the lid 4 may be molded by a powder molding press method.

  On the other hand, when the base 1 and the lid 4 are made of a metal material, they are formed into a predetermined shape by a cutting method, a press method, a MIM (Metal Injection Mold) method, or the like.

  Further, when the base 1 and the lid 4 are made of a metal material, the surface thereof is subjected to a coating treatment such as Au or Ni plating or resin coating such as polyimide in order to prevent corrosion. Is desirable. For example, in the case of Au plating treatment, the thickness is desirably about 0.1 to 5 μm.

  The base 1 and the lid 4 as described above should be reduced in thickness in order to enable the fuel reformer 11 to be reduced in size and height, but the bending strength, which is mechanical strength, is 200 MPa. The above is preferable.

  Next, the external lead terminal 2 in the present invention is preferably made of a metal that is the same as or close to the thermal expansion coefficient of the base 1 and the lid 4, and is made of, for example, an Fe—Ni alloy or an Fe—Ni—Co alloy. However, it is possible to prevent the occurrence of thermal strain with respect to temperature changes during practical use. In addition, a good sealing property between the external lead terminal 2 and the substrate 1 can be obtained, and the bonding property is excellent, and the strength necessary for mounting and good solderability and weldability can be ensured.

Further, the insulating sealing material 8 in the present invention is made of, for example, a glass material such as borosilicate glass, alkali glass, or insulating glass mainly containing lead, or a ceramic material such as aluminum oxide, and is formed on the substrate 1. The base 1 and the external lead terminal 2 are electrically insulated by the insulating sealing material 8 in the through hole, and the external lead terminal 2 is sealed and fixed. The through-hole through which the external lead terminal 2 formed in the base body 1 is inserted needs to have a size that prevents the base body 1 and the external lead terminal 2 from coming into electrical contact with each other. An inner diameter that can secure a distance of 0.1 mm or more from the lead terminal 2 to the base 1 is required.

When the insulating sealing material 8 is made of a ceramic material such as aluminum oxide, the external lead terminal 2 is inserted into the through hole of the base 1 via the insulating sealing material 8 made of, for example, a cylindrical ceramic material, and insulated. The connection between the sealing material 8 and the substrate 1 and the connection between the insulating sealing material 8 and the external lead terminal 2 can be made with a brazing material such as Au—Ge or Ag—Cu.

  The electrode 7 on the fuel reformer 9 and the external lead terminal 2 are electrically connected via the bonding wire 3. Further, by sealing the cavity of the base body 1 using the lid 4, the fuel reformer 11 is formed in which the fuel reformer 9 accommodated in the cavity of the fuel reformer storage container is hermetically sealed. The

The fuel reformer 9 accommodated in the fuel reforming apparatus 11 according to the present invention is an apparatus for reforming fuel, and a fine flow path or void in which a catalyst for reforming the fuel is supported. Have

  The shape of the fuel reformer 9 is various. For example, as a fine chemical device, by applying a semiconductor manufacturing technology or the like, for example, a semiconductor such as silicon, a substrate of an inorganic material such as quartz, glass, metal, ceramics, A liquid flow path is created by forming a narrow groove by a cutting method, etching method, blasting method, etc., and for the purpose of preventing evaporation of the liquid during operation, a glass plate, a metal cover, etc. are anodic bonded, brazed, For example, a substantially rectangular shape is used which is used in close contact with the surface by welding or the like. Moreover, it is a tube made of an inorganic material such as quartz, glass, metal, ceramics, etc., and the inner surface of which is supported with a catalyst for reforming the fuel.

  When the fuel reforming reaction is an endothermic reaction such as a steam reforming reaction, the fuel reformer 9 has a temperature control mechanism, for example, a thin film heater (not shown) or a thick film heater (not shown) composed of a resistance layer or the like. The electrode 7 is formed on the surface as a terminal for supplying power to the heater. By adjusting the temperature condition to about 200 to 800 ° C. corresponding to the fuel reforming condition by this temperature adjusting mechanism, the fuel supplied from the fuel supply port to which the supply pipe 5a is connected is caused to react with the water vapor. The reforming reaction for generating hydrogen gas from the discharge pipe 5b connected to the discharge port can be favorably promoted.

  Such a heater is disposed in or near the flow path, the gap, or the like where the catalyst in the fuel reformer 9 is supported and reforms the fuel. Thereby, the heat generated from the heater can be efficiently used for the fuel reforming reaction.

  The fuel reformer 9 is formed by attaching the cover 4 to the base body 1 by covering the concave portion with a metal brazing material such as an Au alloy, an Ag alloy, an Al alloy, or a glass material, or by a seam weld method. The fuel reformer is stored in a container for storing the fuel reformer.

In the manufacturing method of the fuel reforming apparatus 11 of the present invention, the inner pressure of the cavity is below 10 2 ^Pa. Thereby, heat can be effectively prevented from being transmitted to the base body 1 and the lid body 4 by the radiant heat from the fuel reformer 9. When the internal pressure of the cavity exceeds 10 ² Pa, heat is easily transmitted to the base 1 and the lid 4 by the radiant heat from the fuel reformer 9, and the self-activation of the gas adsorbent 10 is likely to occur. However, the activity power tends to decrease in a short time.

  Preferably, the base 1 and the lid 4 are joined by a welding method such as a projection method, a seam welder method, an electron beam method, or a laser beam method. In the joining of the base body 1 and the lid body 4 by such a welding method, since only the joint portion of the base body 1 and the lid body 4 and the vicinity thereof are heated, the gas adsorbent 10 can be suppressed from being heated, The gas adsorption 10 is not activated when the fuel reformer 11 is sealed.

Further, the joining of the base body 1 and the lid body 4 by the welding method is preferably performed under a low pressure of less than 10 ² Pa in order to prevent the adsorption characteristics of the gas adsorbent 10 from deteriorating.

Moreover, Ru is performed junction between the substrate 1 and the cover 4 at a pressure equal to or smaller than ¹⁰ 2 Pa. When bonding is performed under a pressure exceeding 10 ² Pa, the gas adsorbent 10 is activated by the reaction heat generated when adsorbing the surrounding gas, the activation proceeds, and the adsorption characteristics may be deteriorated.

  Further, when the internal pressure in the fuel reformer storage container 11 is lowered and the degree of vacuum is increased, more gas adsorbents 10 are required. As a result, the gas adsorbents in the fuel reformer storage container 11 are installed. There is a risk of exceeding the allowable amount.

  In addition, the joint between the base body 1 and the lid 4 and the periphery thereof are oxidized during welding, and outgas may be released from the part due to the influence of temperature during fuel reforming and the passage of time.

  In the fuel reformer 9, the electrode 7 on the fuel reformer 9 is electrically connected to the external lead terminal 2 provided on the substrate 1 through the bonding wire 3. Thereby, the heater formed on the surface or inside of the fuel reformer 9 can be heated through the electrode 7. As a result, the reaction temperature can be maintained in the fuel reformer 9, and the fuel reforming reaction can be stabilized.

The supply pipe 5a and the discharge pipe 5b are a supply path for raw materials and fuel gas fluid and a discharge path for reformed gas containing hydrogen, respectively. These include, for example, Fe-Ni alloy, Fe-Ni-Co alloy, a metal material such as SUS, _Al 2 _{O 3} sintered _material, 3Al ₂ O 3 · 2SiO ₂ sintered material, SiC sintered material, It is formed of a ceramic material such as an AlN sintered body, a Si ₃ N ₄ sintered body, a glass ceramic sintered body, a high heat-resistant resin material such as polyimide, or glass.

  Preferably, it is difficult to be embrittled by hydrogen contained in the reformed gas. Such materials include Fe alloys, ceramics, and glass.

  The gas adsorbing material 10 performs vacuum evacuation by utilizing the gas adsorption action of chemically active metal powder, and is one or both sides of a metal plate made of Ni—Cr or the like having a thickness of about 10 to 500 μm. And a metal powder containing Zr, Fe, V, etc. as a main component and having a thickness of 10 μm to 1 mm.

  In addition, since the surface of the metal powder of the gas adsorbent 10 is usually covered with an oxide film, the gas adsorbing action does not appear as it is. The metal powder of the gas adsorbent 10 is heated, and the oxide film on the surface diffuses into the adsorbent and a new active surface appears on the surface, whereby the gas adsorbing action is activated (activated).

  The heating of the gas adsorbing material 10 is performed by causing the metal material inside the gas adsorbing material to generate heat by transmitting electric energy from an external power source through a lead terminal to the metal material inside the gas adsorbing material. The gas adsorbent 10 is irradiated with light rays such as infrared rays and laser light through the provided window, and the energy of the light rays is directly converted into thermal energy by the gas adsorbent 10.

  The gas adsorbent 10 may be mounted on the inner surface of the cavity of the substrate 1 directly or via a pedestal or the like, or may be mounted on the fuel reformer 9. In addition, as shown in FIG. 1, it is connected to a lead terminal to transmit electric energy from an external power source through the lead terminal, and this electric energy is transmitted to the metal plate of the gas adsorbent 10 and converted into heat energy by this metal plate. Heating of the gas adsorbent 10 may be performed supplementarily.

  In addition, this invention is not limited to the example of the above embodiment, A various change may be added in the range which does not deviate from the summary of this invention. For example, in the example shown in FIG. 1, the gas adsorbent 10 is joined to the lead terminal 12, but an insulating base such as ceramic may be used.

It is sectional drawing which shows an example of embodiment of the fuel reforming apparatus in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Base | substrate 4 ... Lid body 5a ... Supply pipe 5b ... Discharge pipe 9 ... Fuel reformer 10 ... Gas adsorbent 11 ... ..Fuel reformer

Claims (3)

A fuel reformer for generating reformed gas containing hydrogen gas from fuel, a base having a cavity in which the fuel reformer is accommodated, and a lid attached to the upper surface of the base so as to cover the cavity A discharge pipe that communicates the inside of the cavity with the outside so as to discharge the reformed gas from the fuel reformer, and a communication between the inside of the cavity and the outside so as to supply the fuel to the fuel reformer. a supply pipe for, and comprises a gas adsorbent housed in said cavity, said method of manufacturing a fuel reforming apparatus in which the internal pressure of the cavity and 10 2 ^Pa or less, 10 2 ^Pa or less in pressure A method for manufacturing a fuel reformer , comprising: storing the gas adsorbent in the cavity and bonding the base and the lid . The lid is made of a metal material having a thermal conductivity of 120 W / mK or less.
A method for producing the fuel reformer as described. 3. The method of manufacturing a fuel reformer according to claim 1, wherein the lid and the base are joined by any one of a projection method, a seam welder method, an electron beam method, and a laser beam method .

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