JP5703759B2 - Gas decomposition apparatus and power generation apparatus - Google Patents

Description

  The present invention relates to a gas decomposition apparatus and a power generation apparatus. Specifically, the present invention relates to a gas decomposition apparatus capable of efficiently decomposing a predetermined gas and a power generation apparatus including the gas decomposition apparatus.

  For example, ammonia is an indispensable compound for agriculture and industry, but is harmful to humans, so various methods for decomposing ammonia in water and air are known. In order to decompose and remove ammonia from water containing a high concentration of ammonia, a method has been proposed in which ammonia water is sprayed and contacted with an air stream to separate ammonia in the air and contacted with hypobromous acid solution or sulfuric acid. (Patent Document 1). In addition, a method of separating ammonia in the air by the same process as the above method and burning it with a catalyst (Patent Document 2) and a method of decomposing ammonia-containing wastewater into nitrogen and water using a catalyst have been proposed. (Patent Document 3). Furthermore, the waste gas of the semiconductor manufacturing apparatus often contains ammonia, hydrogen, etc., and in order to completely remove the odor of ammonia, it is necessary to remove it to the ppm order. For this purpose, many methods have been used in which harmful gas is absorbed in water containing chemicals through a scrubber when the waste gas of the semiconductor device is released. On the other hand, in order to decompose harmful gases at a low running cost without input of energy, chemicals, etc., a waste gas treatment method in a semiconductor manufacturing apparatus or the like that decomposes ammonia with a phosphoric acid fuel cell has been proposed (patent) Reference 4).

JP-A-7-31966 Japanese Patent Laid-Open No. 7-116650 Japanese Patent Laid-Open No. 11-347535 JP 2003-45472 A Japanese Patent No. 3238086

  A method using a chemical such as a neutralizing agent as described in Patent Document 1, a method of burning as described in Patent Document 2, and a thermal decomposition using a catalyst as described in Patent Document 3 Ammonia can be decomposed by a reaction method. However, these methods require chemicals and external energy (fuel), and further require periodic replacement of the catalyst, resulting in increased running costs.

  In addition, since the apparatus becomes large, it is difficult to secure a space when it is additionally provided in existing facilities. In addition, for the device that uses phosphoric acid fuel cells to remove ammonia in the exhaust gas from the production of compound semiconductors, the electrolyte is liquid, so the partition between the air side and the ammonia side cannot be made compact, and the size of the device is reduced. There was a problem that was difficult.

  In order to solve the above problem, as described in Patent Document 5, a cylindrical solid electrolyte layer, and a first electrode layer and a second electrode layer formed so as to sandwich the solid electrolyte layer from inside and outside A cylindrical MEA (Membrane Electrode Assembly) configured with the above can be employed. A gas containing a gas to be decomposed is caused to flow in the axial direction in the inner space of the cylindrical MEA.

  In order to decompose the gas, it is preferable that the temperature of the gas containing the gas is increased as much as possible to act on the first electrode layer (fuel electrode) of the cylindrical MEA. For this reason, the heater which heats the whole said cylindrical MEA is provided.

  In the conventional cylindrical MEA, a connection member is connected to both ends so that gas flows in one direction in the internal space of the cylindrical MEA. However, as described above, since the entire tubular MEA is kept at a high temperature, the sealing performance between the both ends of the tubular MEA and the connecting member is likely to be lowered, and the connection reliability is low. was there.

  Moreover, since the whole gas decomposition element comprised including the said cylindrical MEA will be provided in the heating container provided with the said heater, it is high also in the said connection member and connection piping connected to this. Heat resistance is required. For this reason, it is necessary to form the sealing structure and connection piping between these with expensive heat-resistant material, and increase the manufacturing cost of an apparatus.

  Furthermore, in order to increase the gas decomposition efficiency, it is preferable to set a long gas flow distance in the cylindrical MEA. For this reason, the cylindrical MEA is often formed in a long cylindrical shape. However, the cylindrical MEA has a low strength because it is formed by sintering powder such as ceramic, and is exposed to a high temperature close to 1000 ° C. For this reason, when installed in a state where stress is applied, there is a problem that breakage and cracks are likely to occur. In particular, when the shaft is oriented in the lateral direction, the bending moment tends to concentrate on the fixed part, and the risk of breakage increases.

  According to the present invention, the temperature of the gas flowing in the cylindrical MEA can be increased to further improve the decomposition efficiency, and the external piping, the connecting member connecting the external piping, and the seal structure provided therebetween are damaged by heat. It is an object of the present invention to provide a gas decomposition apparatus capable of preventing the damage and further preventing damage to the cylindrical MEA itself.

The present invention includes a cylindrical solid electrolyte layer, a first electrode layer formed on the inner periphery of the solid electrolyte layer, and a second electrode layer formed on the outer periphery of the solid electrolyte layer. A gas decomposition apparatus configured using a tubular MEA (Membrane Electrode Assembly) having a heating container that houses and heats the tubular MEA, and one end of the tubular MEA is sealed. And a gas induction pipe which is inserted into the inner space of the cylindrical MEA and forms a cylindrical flow path between the sealing portion disposed in the heating container and the inner surface of the cylindrical MEA. a projection projecting from the heating container together is provided continuously to the cylindrical MEA, and a connection member provided on the open end of the protruding portion, the tubular in a posture oriented in the axial vertically MEA Keep hold Means, and a pre-heating pipe for preheated gas led to the gas induction pipe through the heating vessel, the connecting member is provided with a gas inlet communicating with the gas induction pipe, the An annular exhaust space that surrounds the outer periphery of the gas induction pipe and has a gas discharge part on the side is provided .

  In the gas decomposition apparatus according to the present invention, in order to obtain high gas decomposition performance, it is necessary to keep the cylindrical MEA at a high temperature, for example, 800 ° C. or more. For this reason, while the said heating container is provided, cylindrical MEA is accommodated in the said heating container.

In the present invention, the cylindrical MEA is provided with a protruding portion that protrudes to the outside of the heating container, and the connection member is provided at the tip of the protruding portion. That is, the connection member is provided outside the heating container and at a position away from the heating container. As the connection member, a gas introduction part communicating with the gas induction pipe and a ring exhaust space that surrounds the outer periphery of the gas induction pipe and has a gas discharge part on the side can be adopted. With this configuration, the amount of heat conducted from the cylindrical MEA in the heating container to the connecting member is reduced, and the temperature of the connecting member is reduced. Therefore, it is possible to prevent the sealing performance between the cylindrical MEA and the connecting member from being lowered and to prevent gas leakage and the like. In addition, high heat resistance is not required for the connecting member and the pipe connected thereto, so that the connection reliability is increased and the manufacturing cost can be reduced.

The configuration of the protruding portion is not particularly limited. The upper SL protrusion, a portion of the tubular MEA, can be configured to protrude from the heating container.

Moreover , a part or all of the projecting part can be formed from the cylindrical MEA and a separate member. For example, the protruding portion can be formed by connecting a cylindrical ceramic member formed in a form continuous to the cylindrical MEA to an end of the cylindrical MEA.

  It is preferable that the separate member constituting the protruding portion is formed of a material having heat resistance and heat insulation. However, heat insulation is not essential. That is, various materials can be employed as long as the temperature acting on the connecting member can be reduced. For example, a ceramic having high heat resistance and high heat insulation can be employed. Further, when the protruding portion is formed of a metal material having high thermal conductivity such as nickel, the temperature that acts on the connecting member and the piping member is released by releasing heat conducted from the cylindrical MEA in the protruding portion. It can also be configured to reduce.

  Moreover, in this invention, the holding means which hold | maintains the said cylindrical MEA in the attitude | position which orientated the axis | shaft to the up-down direction via the said protrusion part or the said connection member is provided.

As long as the cylindrical MEA can be positioned and held by orienting the shaft in the vertical direction, the site, form and structure of the holding means are not particularly limited. On SL holding means, through the projection or the connecting member may be configured to hold the cylindrical MEA. For example, a holding member that can be connected to the connecting member or the protruding portion by a screw or the like can be provided. Moreover, it can comprise and comprise the holding member which can be fitted and hold | maintained to the said connection member or the said protrusion part.

In addition , the holding means can be configured to hold the cylindrical MEA via the heating container. For example, it can be configured so that a cylindrical MEA can be oriented and held by providing a flange or the like in the penetration portion of the heating container.

  When the axis of the cylindrical MEA is oriented vertically and held so as to be suspended by the projecting portion or the connecting member, no bending moment acts on the cylindrical MEA. For this reason, stress is not concentrated on a part of the cylindrical MEA, and damage to the cylindrical MEA can be prevented. The orientation angle of the cylindrical MEA is not particularly limited, but it is preferable to hold the cylindrical MEA so as to be suspended from above via the protruding portion or the connecting portion with the axis oriented in the vertical direction. .

  Moreover, when gas is decomposed | disassembled using the said cylindrical MEA, a water | moisture content may be produced | generated. For example, when ammonia gas is decomposed using the inside of the cylindrical MEA as an anode, the oxygen ion conductive solid electrolyte is a reaction that generates water on the cylindrical inside (anode). Water forms water droplets near the gas outlet having a low temperature and causes pressure loss. In particular, when the cylindrical MEA is installed with the axis oriented in the lateral direction, the water droplets are likely to stay, so a mechanism for discharging the water droplets is required.

  On the other hand, in the present invention, since the cylindrical MEA is installed with the axis oriented in the vertical direction, even if water droplets are generated near the discharge port of the cylindrical MEA, it falls downward due to gravity, and the discharge port Water drops do not stay in the vicinity. Also, a mechanism for discharging the dropped water droplets can be easily configured. In particular, in the present invention, since the protruding portion protruding from the heating container is provided, water droplets are likely to be generated inside this portion. However, if gas is discharged from above, the protruding portion or the connecting member generates the water droplet. The water droplets fall into the hot cylindrical MEA and become steam, and can be discharged as a gas together with the exhaust gas.

In addition , the cylindrical MEA is provided with a lower end sealed, and is inserted into a sealing portion disposed in the heating container and an internal space of the cylindrical MEA. A gas induction pipe that forms a cylindrical flow channel with the peripheral surface is provided, and the gas introduced into the gas induction pipe through the connection member provided at the upper end is directed toward the sealing portion. The first electrode layer is made to flow and reversely flow by flowing out from the inside of the induction pipe in the vicinity of the sealing portion, and the cylindrical flow path is made to flow in a direction opposite to the flow in the gas induction pipe. It can be configured to be decomposed by acting on and discharged through the connecting member .

  By adopting the above configuration, it is possible to provide a connection member for allowing gas to enter and exit only at the upper end, and it is sufficient to provide a sealing structure between the cylindrical MEA and the connection member in one place. Therefore, the reliability of connection is increased. In addition, the number of parts and processing steps can be reduced. In addition, the cylindrical MA can be held by being suspended by holding means provided above the heating container. Therefore, the structure of the apparatus can be simplified.

  In addition, by adopting the above configuration, the gas flowing through the cylindrical MEA can flow a distance twice as long as the cylindrical length of the cylindrical MEA. For this reason, after raising the temperature of gas in the said gas induction pipe, it can be made to act on the said cylindrical MEA. Therefore, it is possible to increase the gas decomposition efficiency, and it is possible to increase the gas throughput by increasing the gas flow rate.

  The structure which seals the one end part of the said cylindrical MEA is not specifically limited. For example, one end of the cylindrical MEA can be sealed with a bottom formed by integrally extending the solid electrolyte layer. Since the bottom part is integrally formed with the cylindrical MEA in the molding and sintering steps, there is no risk of gas leakage, and one end of the cylindrical MEA can be reliably sealed.

  Moreover, the one end part of the said cylindrical MEA can also be sealed using a sealing member. By adopting this configuration, the present invention can be applied to a conventional cylindrical MEA having both ends opened.

A connecting member having a double structure is provided at the gas inlet / outlet of the cylindrical MEA so that the gas before decomposition and the gas after decomposition do not mix. The connection member includes a gas introduction portion communicating with the gas induction pipe, and includes an annular exhaust space that surrounds the outer periphery of the gas induction pipe and includes a gas discharge portion on a side portion . By adopting the connection member, it is possible to introduce a gas containing a gas to be decomposed and discharge a gas containing the decomposed gas from one side of the cylindrical MEA.

  The gas induction pipe can be used as a current collector for the first electrode layer. That is, the gas induction pipe can be formed from a conductive material, and can be electrically connected to the first electrode layer to constitute a current collector of the first electrode layer.

  By using the gas induction pipe as a current collector for the first electrode layer, not only the gas decomposition efficiency can be increased, but also the space in the cylindrical MEA can be effectively utilized. In addition, a wiring conducting to the gas induction pipe can be provided in the protruding portion.

  Although the material which comprises the said gas induction pipe is not specifically limited, It is necessary to form with the material which corrosion etc. do not produce by the gas to decompose | disassemble. For example, it can be formed using a material such as a nickel alloy such as stainless steel, nickel, or Inconel (registered trademark of Special Metal Co.).

  The method for electrically connecting the first electrode layer and the gas induction pipe is not particularly limited. For example, a porous metal body having conductivity is inserted into a cylindrical flow path formed between the inner peripheral surface of the cylindrical MEA and the outer peripheral surface of the gas induction pipe, and the first electrode layer and the above The gas induction pipe can be conducted. Further, by providing the porous metal body, it is possible to secure a cylindrical flow path between the inner peripheral surface of the first electrode layer and the outer peripheral surface of the gas induction pipe, and the gas induction pipe. Can be positioned and held in the cylindrical MEA.

On SL holding means, together they are configured to hold the tubular MEA through the protrusion, in a plate shape convective heat and radiant heat from the heating container to shield from acting on the connecting member Can be formed .

  In this invention, since the connection member is provided via the protrusion part, high temperature does not act directly on a connection member from a heating container. However, heat due to convection or radiation acts on the connection member. The present invention uses the holding means to reduce the heat conduction acting on the connecting member.

  The plate-like holding means is preferably provided so as to shield the connection member from the heat radiation surface of the heating container. By adopting the above configuration, a plate-like holding means is interposed between the connection member and the heating container. For this reason, it can prevent that the convection heat and radiant heat from the upper part of the said heating container hold | maintained at high temperature, or the lower end part of a protrusion part act on the said connection member. Therefore, it is possible to mitigate an increase in the temperature of the connecting member.

It can be provided a cooling means for cooling the upper Symbol protrusion. The configuration of the cooling means is not particularly limited. For example, a radiating fin or the like can be provided on the protruding portion. In addition, cooling can be performed by using cooling air or cooling water in the protruding portion. This makes it possible to easily set the temperature at the tip of the protrusion.

  Moreover, when the said protrusion part is formed with the said cylindrical MEA and another member, a cooling means can also be integrally formed in a protrusion part.

The upper SL projecting tip temperature is preferably set to 205 ° C. or less. The means for setting the temperature range is not particularly limited. For example, the temperature can be set using the cooling means. Moreover, the said temperature can also be set by adjusting the length of the said protrusion part. The set temperature can be set according to the heat resistance of the seal structure between the connection members and the heat resistance of the connection members and the connection pipes.

  By adopting the above configuration, it is possible to reliably prevent the sealing structure between the opening end portion and the connection member and the connection member from being damaged by heat. Moreover, it becomes possible to employ | adopt the member formed from the material with low heat resistance for the said connection member or piping member, and can reduce manufacturing cost.

By employ | adopting the said structure, the temperature which acts on the said connection member can be reduced significantly. Thereby , the connection member can be formed from a resin material. The kind of the resin material is not particularly limited. For example, a fluororesin such as Teflon resin (a registered trademark of DuPont) can be used. In addition, by forming the connecting member from a resin material, it is possible to easily perform processing and the like, and the manufacturing cost can be reduced.

Further, the passing over Symbol heating vessel, and configured to include a pre-heating pipe for pre-heating the gas introduced into the gas induction pipes.

  By providing the preheating pipe, it is preheated in the preheating pipe before being introduced into the cylindrical MEA. For this reason, the preheated gas is introduced into the cylindrical MEA and can be efficiently heated to a predetermined temperature required for gas decomposition. For this reason, the decomposition efficiency of gas can be increased. In addition, the length of the cylindrical MEA can be set short.

  The said preheating piping can also be provided for every said cylindrical MEA, and it can also comprise so that the gas introduce | transduced into several cylindrical MEA may be preheated by one preheating piping.

The materials constituting the first electrode layer and the second electrode layer are not particularly limited. For example , the first electrode layer and / or the second electrode layer may be a fired body including a metal particle chain body mainly composed of nickel (Ni) and an ion conductive ceramic. The metal particle chain refers to a bead-like elongated metal body formed by connecting metal particles. Ni, Fe-containing Ni, or Ni, Fe-containing Ni may be a metal containing a small amount of Ti. In a state where Ni or the like is oxidized, the surface of the metal particle chain is oxidized, and the contents (portion inside the surface layer) are not oxidized and retain the conductivity of the metal.

For this reason, for example, when the ion moving in the solid electrolyte layer is an anion (in some cases, it is a cation), the following effects are produced.
(A1) When a metal particle chain is contained in the first electrode layer (anode), in the first electrode layer (anode), the anion moving from the solid electrolyte layer and the first electrode layer ( The chemical reaction with the gas molecules in the gas led from the outside of the anode) to the first electrode layer (anode) is promoted by the oxidation layer of the metal particle chain (catalysis), and an anion is added. The chemical reaction in the first electrode layer (anode) is promoted (acceleration effect by electric charge). And as a result of the chemical reaction, the conductivity of the generated electrons can be ensured by the metal portion of the metal particle chain. As a result, the electrochemical reaction involving charge transfer in the first electrode layer (anode) can be accelerated as a whole. When the metal particle chain is contained in the first electrode layer (anode), a cation, for example, a proton is generated in the first electrode layer (anode), and the second electrode layer (cathode) is generated in the solid electrolyte layer. The cation can be moved to the surface, and the above-mentioned promoting action by the charge can be obtained similarly.
However, the oxide layer of the metal particle chain is surely formed by firing before use, but the oxide layer is often lost due to a reduction reaction during use. Even if the oxide layer disappears, the above-described catalytic action may or may not be reduced. In particular, Ni containing Fe or Ti has high catalytic action even without an oxide layer.
(A2) When the second electrode layer (cathode) contains a metal particle chain in the second electrode layer (cathode), the second electrode layer (cathode) from the outside of the second electrode layer (cathode). The chemical reaction of gas molecules in the gas led to gas) is promoted by the oxidation layer of the metal particle chain (catalysis), and the conductivity of the electrons from the external circuit is improved and the electrons are allowed to participate. The chemical reaction at the second electrode layer (cathode) is promoted (acceleration effect by electric charge). Then, anions can be efficiently generated from the molecules and delivered to the solid electrolyte layer. As in (A1), in the case of (A2), the electrochemical reaction between the cation that has moved through the solid electrolyte layer, the electrons that have flowed through the external circuit, and the second gas can be promoted. For this reason, the electrochemical reaction accompanied by transfer of electric charge in the second electrode layer (cathode) can be accelerated as a whole, as in the case of being included in the first electrode layer (anode). In what case, the metal particle chain is included in the second electrode layer (cathode) depending on the gas to be decomposed.
(A3) When the metal particle chain is contained in the first electrode layer (anode) and the second electrode layer (cathode), the effects (A1) and (A2) can be obtained.

  In many cases, the electrochemical reaction is limited by the moving speed or moving time of the solid electrolyte layer of ions. In order to increase the moving speed of ions, the gas decomposing apparatus generally includes a heating device that can accommodate the entire cylindrical MEA, such as a heater, and is usually set to a high temperature, for example, 600 ° C to 1000 ° C. By raising the temperature, not only the ion transfer speed but also a chemical reaction accompanied by charge transfer in the electrode layer is promoted.

  When the ions moving through the solid electrolyte layer are anions, they are generated and supplied by a chemical reaction at the second electrode layer (cathode) as described above. Molecules in the fluid and electrons introduced in the second electrode layer (cathode) react to generate anions. The generated anion moves in the solid electrolyte layer to the first electrode layer (anode). The electrons participating in the reaction at the second electrode layer (cathode) include an external circuit (capacitor, power source, and power consuming device) that connects the first electrode layer (anode) and the second electrode layer (cathode). ) Comes in. When the ions moving through the solid electrolyte layer are cations, they are generated by an electrochemical reaction in the first electrode layer (anode) and move through the solid electrolyte layer to the second electrode layer (cathode). Electrons are generated at the first electrode layer (anode) and flow through an external circuit to the second electrode layer (cathode) to participate in the electrochemical reaction at the second electrode layer (cathode). The electrochemical reaction may be a power generation reaction as a fuel cell, or may be an electrolysis reaction.

The solid body electrolyte layer can have a structure having oxygen ion conductivity or proton conductivity. When an oxygen ion conductive solid electrolyte is used, for example, electrons and oxygen molecules are reacted in the second electrode layer (cathode) to generate oxygen ions, which are then moved through the solid electrolyte layer. A predetermined electrochemical reaction can be caused in the first electrode layer (anode). In this case, since the moving speed of oxygen ions in the solid electrolyte layer is not large compared to protons, the temperature is sufficiently increased and / or the thickness of the solid electrolyte layer is sufficiently thin to obtain a practical level of decomposition capacity. Such measures are necessary.

On the other hand, barium zirconate (BaZrO ₃ ) is known as a proton conductive solid electrolyte. When a proton conductive solid electrolyte is used, for example, ammonia is decomposed in the first electrode layer (anode) to generate protons, nitrogen molecules and electrons, and the protons are passed through the solid electrolyte layer to form the second electrode layer (cathode). ) To react with oxygen in the second electrode layer (cathode) to produce water (H ₂ O). Since protons are small compared to oxygen ions, the moving speed in the solid electrolyte layer is high, and a practical decomposition capacity can be obtained by lowering the heating temperature.

  For example, when ammonia decomposition is performed using a cylindrical MEA, the oxygen ion conductive solid electrolyte layer is a reaction that generates water in the first electrode layer (anode) of the cylindrical MEA. Water forms water droplets near the outlet where the temperature is low, causing pressure loss. In contrast, when a proton conductive solid electrolyte layer is used, protons, oxygen molecules, and electrons are generated at the second electrode layer (cathode) (outside). Since the outside is almost open, even if it adheres as water droplets, pressure loss is unlikely to occur.

The decomposition target gas as fuel, it is also possible to configure the power generating device comprises a gas decomposition apparatus according to the present invention described above.

  In addition to high gas decomposition efficiency, it is possible to provide a gas decomposition apparatus with high connection reliability.

It is a longitudinal section which shows the structure in the heating container of the gas decomposition apparatus which concerns on 1st Embodiment of this invention. It is sectional drawing which follows the II-II line in FIG. It is a figure which shows the electrical wiring system | strain of the gas decomposition apparatus of FIG. It is a longitudinal cross-sectional view by the side of the protrusion part (opening end side) of the gas decomposition apparatus shown in FIG. It is an expanded longitudinal cross-sectional view of the principal part of the gas decomposition apparatus which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the gas decomposition apparatus which comprised the gas decomposition element shown in FIG. 5 using multiple pieces. It is sectional drawing which follows the VII-VII line in FIG.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a gas decomposition apparatus 100 according to a first embodiment of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. In the present embodiment, a gas decomposing apparatus in the case where the first gas used for decomposition is an ammonia-containing gas will be described.

  In the present embodiment, one gas decomposition element 10 composed of one cylindrical MEA 7 is accommodated in a heating container 51 to constitute a gas decomposition apparatus 100. In addition, a gas decomposition apparatus can be comprised by arrange | positioning the several gas decomposition element comprised by providing the said cylindrical MEA7 in one heating container.

The gas decomposition element 10 is provided with a first electrode layer (anode) 2 so as to cover the inner surface of the cylindrical solid electrolyte layer 1, and a second electrode layer (cathode) 5 so as to cover the outer surface. The cylindrical MEA 7 (1, 2, 5) is provided. The first electrode layer (anode) 2 may be called a fuel electrode, and the second electrode layer (cathode) 5 may be called an air electrode.
In the present embodiment, as described above, the ammonia-containing gas flows as the first gas inside the cylindrical MEA 7 (1, 2, 5). In addition, air, which is an oxygen-containing gas, flows as the second gas outside the cylindrical MEA 7 (1, 2, 5). A flow path inside the cylindrical MEA 7 (1, 2, 5) through which the first gas flows is defined as a first gas flow path. The flow path outside the cylindrical MEA 7 (1, 2, 5) through which the second gas flows is defined as a second gas flow path.
The cylindrical MEA 7 (1, 2, 5) according to the present embodiment is formed in a right cylindrical shape as shown in FIG. The inner diameter of the cylindrical MEA 7 (1, 2, 5) is, for example, about 20 mm, but the dimensions and the like can be set according to the device to be applied.

  In the gas decomposing element 10 of the present embodiment, the cylindrical MEA 7 (1, 2, 5) is sealed at its lower end and a gas induction pipe 11k is inserted from the upper end. The gas induction pipe 11k is an alloy containing iron, chromium, niobium, molybdenum or the like based on Ni such as stainless steel, copper, nickel, and inconel, that is, heat resistance to 600 to 1000 ° C. and ammonia gas corrosion resistance. Consists of a material with The lower end portion is provided with a sealing portion 44 by extending the solid electrolyte layer 1 and the inner electrode layer 2 of the cylindrical MEA 7 (1, 2, 5) and providing a bottom portion.

  The gas induction pipe 11k is inserted from the upper end portion of the cylindrical MEA 7 (1, 2, 5) toward the sealing portion 44 that is the lower end portion, and the first electrode layer of the cylindrical MEA 7 is inserted. The cylindrical flow path 43 is set between the inner peripheral surface 2 and the outer peripheral surface of the gas guide pipe 11k. A porous metal body 11s is inserted into the cylindrical flow path 43, and the gas guide pipe 11k is held at the center while the outer peripheral surface of the gas guide pipe 11k and the first electrode layer 2 are in contact with each other. A cylindrical flow path 43 is formed between the inner peripheral surface.

  In the gas decomposition element 10 according to the present embodiment, the first gas is caused to flow toward the sealing portion 44 in the internal space 42 of the gas guiding pipe 11k, and the gas guiding pipe is disposed in the vicinity of the sealing portion 44. The first gas is allowed to flow out from the inside of 11k and reversed, and the first gas is caused to flow in the direction opposite to the flow in the internal space 42 through the cylindrical flow path 43. That is, the internal space 42 and the cylindrical flow path 43 constitute the first gas flow path.

  By adopting the above configuration, in the space inside the cylindrical MEA 7, a distance about twice the cylinder length of the cylindrical MEA 7 can be used as the first gas flow path. For this reason, it can be made to act on the said cylindrical MEA7 in the state heated enough in the said gas induction pipe 11k, and temperature rising. Therefore, the decomposition efficiency of the first gas can be increased, and the gas flow rate can be increased to increase the gas throughput.

  The gas induction pipe 11k is made of a conductive metal such as stainless steel, and is configured to function as a component of the anode current collector 11. On the other hand, the cathode current collector 12 is arranged so as to wrap around the outer surface of the second electrode layer (cathode) 5.

The anode side current collector 11 includes a silver paste coating layer 11g, a Ni mesh sheet 11a, a porous metal body 11s, and the gas induction pipe 11k. The Ni mesh sheet 11a is in contact with the first electrode layer (anode) 2 on the inner surface side of the cylindrical MEA 7 through the silver paste coating layer 11g, and conducts from the porous metal body 11s to the gas induction pipe 11k. Is configured to do. The tip portion W ₁ of the Ni mesh sheet 11a is in the vicinity of the sealing portion 44 is conductively connected to wind through the bonding member W ₂ band-like on an outer peripheral portion of the gas introduction pipe 11k . Therefore, the Ni mesh sheet 11a includes, in parallel, a conductive path of (1) Ni mesh sheet 11a / porous metal body 11s / gas induction pipe 11k, and (2) Ni mesh sheet 11a / gas induction pipe 11k, The conductive path is formed. As a result, it is possible to prevent an increase in pressure loss while being located on the inner surface of the cylindrical MEA 7 and maintaining a low electrical resistance.

  As the porous metal body 11s, in order to reduce the pressure loss of the first gas, it is preferable to use a metal plated body that can increase the porosity, such as Celmet (registered trademark: Sumitomo Electric Industries, Ltd.). In order to reduce the electrical resistance between the first electrode layer (anode) 2 and the anode-side current collector 11, the silver paste coating layer 11g and the Ni mesh sheet 11a are disposed.

  The cathode current collector 12 includes a silver paste coated wiring 12g and a Ni mesh sheet 12a. In the present embodiment, the Ni mesh sheet 12a contacts the outer surface of the cylindrical MEA 7 and conducts to the external wiring 12e. The silver paste coated wiring 12g contains silver that acts as a catalyst for promoting the decomposition of oxygen in the oxygen-containing gas (air), which is the second gas, into oxygen ions in the second electrode layer (cathode) 5. In addition, this contributes to lowering the electrical resistance of the cathode current collector 12. The silver paste coated wiring 12g has a catalytic action equivalent to that of the silver particles contained in the second electrode layer (cathode) 5 by contacting the silver particles with the second electrode layer (cathode) 5 while passing oxygen molecules. To express. Moreover, it is less expensive than the inclusion in the second electrode layer (cathode) 5.

  A heating vessel 51 provided with a space S for flowing the second gas is provided outside the cylindrical MEA 7 (1, 2, 5). A heater 52 is disposed on the outer periphery of the heating container 51. In the present embodiment, a preheating pipe 53 is arranged in the space S so as to penetrate the heating container 51.

The heater 52 is for heating the gas decomposition element 10, and the cylindrical MEA 7 is heated to a temperature suitable for decomposition of the first gas by the heater 52. The preheating pipe 53 is a pipe for preheating the first gas. By passing the first gas through the preheating pipe 53 before being introduced into the cylindrical MEA 7, the first gas is preheated, and the first gas having a low temperature is suddenly introduced into the cylindrical MEA 7. To eliminate the lack of reaction. As a result, it is possible to improve the decomposition performance and make the gas decomposition element 10 compact. The preheating pipe 53 includes a connection end 53a connected to the pipe from the first gas source, and the downstream side is connected to the gas introduction pipe 45.
As the preheating pipe 53, a heat-resistant pipe such as a Ni pipe, an Inconel pipe, or other metal or ceramic pipe having heat resistance and corrosion resistance can be used.
Note that only one cylindrical MEA 7 and preheating pipe 53 are shown in FIG. 1, but a plurality of pipes can be provided to constitute a gas decomposition apparatus.
Although the said heating container 51 is comprised with a heat-resistant material, it is good also as what was comprised thickly with the refractory material and embedded the heater 52. FIG. Moreover, it can also be set as the structure which embed | buried and penetrated the preheating piping 53 in the thickness of the heating container 51 which consists of a thick refractory material.
Originally, by using the heater 52 for heating the cylindrical MEA 7, the preheating pipe 53 is heated, and the first gas flowing in the preheating pipe is preheated well. .

FIG. 3 is a diagram showing an electrical wiring system of the gas decomposition element 10 of FIG. 1 when the solid electrolyte layer 1 is oxygen ion conductive. The first gas containing ammonia passes through the preheating pipe 53, and then passes through the gas induction pipe 11k to the innermost part of the inner cylinder of the cylindrical MEA 7 with strict airtightness, that is, the sealing part. It is guided to the vicinity of 44. The entire cylindrical MEA 7 is heated to about 800 ° C. by the heater 52, and the temperature of the first gas is raised while flowing in the gas induction pipe 11k. During this time, ammonia in the first gas is decomposed as 2NH ₃ → N ₂ + 3H ₂ by heating in the gas induction pipe 11k.

  When the cylindrical MEA 7 is used, the porous metal body 11s is used to pass the first gas containing the decomposition gas on the inner surface side and hold the gas induction pipe 11k. From the viewpoint of reducing the pressure loss, as described above, a porous metal plated body, for example, the above-mentioned Celmet (registered trademark) can be used as the porous metal body 11s disposed in the cylindrical flow path 43. . The first gas containing ammonia flows through the first gas flow path from the internal space 42 into the cylindrical flow path 43, and the porous metal body 11s, the Ni mesh sheet 11a, and the porous silver paste coating layer The following ammonia decomposition reaction is performed in contact with the first electrode layer (anode) 2 while passing through the 11 g gap.

Oxygen ions O ²⁻ are generated by an oxygen gas decomposition reaction at the second electrode layer (cathode) 5 and reach the first electrode layer (anode) 2 through the solid electrolyte layer 1. That is, it is an electrochemical reaction when oxygen ions, which are anions, move through the solid electrolyte layer 1.

In the first electrode layer (anode) 2, the following reaction occurs.
(Anode reaction): 2NH ₃ + 3O ²⁻ → N ₂ + 3H ₂ O + 6e ⁻
More specifically, a part of ammonia causes a reaction of 2NH ₃ → N ₂ + 3H ₂ , and this 3H ₂ reacts with oxygen ions 3O ²⁻ to generate 3H ₂ O.
Air, particularly oxygen gas, is introduced into the second electrode layer (cathode) 5 so as to pass through the space S, and oxygen ions decomposed from oxygen molecules in the second electrode layer (cathode) 5 are converted into the first electrode layer. (Anode) 2 is sent to the solid electrolyte layer 1.

In the second electrode layer (cathode) 5, the following reaction occurs.
(Cathode reaction): O ₂ + 4e ⁻ → 2O ²⁻
As a result of the above electrochemical reaction, electric power is generated, and a potential difference is generated between the first electrode layer (anode) 2 and the second electrode layer (cathode) 5, and the anode side current collector 12 performs the anode side current collection. A current I flows to the electric body 11. If a load, for example, a heater 52 for heating the gas decomposition element 10 is connected between the cathode-side current collector 12 and the anode-side current collector 11, electric power for that purpose can be supplied. The supply of the power to the heater 52 may be partial. In many cases, the supply amount of private power generation is less than half of the electric power required for the entire heater 52.

  In the gas decomposition element 10, in the first electrode layer (anode) 2 on the inner surface side of the cylindrical MEA 7, the pressure loss of the first gas passing through the anode-side current collector 11 is lowered while the electrical resistance of the anode-side current collector 11 is lowered. Is important. In addition, on the second electrode layer (cathode) 5 side, the contact portion between the air, which is the second gas, and the second electrode layer (cathode) 5 is densified, and the cathode-side current collector 12 has a resistance. It is important to keep it low.

The above is an electrochemical reaction in which oxygen ions, which are anions, move through the solid electrolyte layer 1. For example, barium zirconate (BaZrO ₃ ) is used for the solid electrolyte layer 1 to transfer protons to the first electrode layer (anode The reaction that is generated in step 2 and moves in the solid electrolyte layer 1 to the second electrode layer (cathode) 5 is also a desirable embodiment of the present invention.

When proton conductive solid electrolyte layer 1 is used, for example, when ammonia in the first gas is decomposed, ammonia is decomposed at first electrode layer (anode) 2 to generate protons, nitrogen molecules, and electrons. Then, protons move to the second electrode layer (cathode) 5 through the solid electrolyte layer 1 and react with oxygen in the second electrode layer (cathode) 5 to generate water (H ₂ O). Since protons are smaller than oxygen ions, the moving speed in the solid electrolyte layer 1 is large. For this reason, a practical decomposition capacity can be obtained while lowering the heating temperature. The thickness of the solid electrolyte layer 1 can also be set to a thickness that can ensure strength.

  FIG. 4 is a diagram showing a connection form between the gas induction pipe 11k and the external wiring 11e, a connection form between the cylindrical MEA 7 and the gas introduction pipe 45 and the exhaust pipe 65, and a holding form of the gas decomposition element 10.

  In the present embodiment, the cylindrical MEA 7 is accommodated in the heating container 51 with the axis oriented in the vertical direction, and the upper end portion of the cylindrical MEA 7 protrudes above the heating container 51 to project the protrusion 41. The connecting member 30 for allowing the first gas to enter and exit is provided at the upper end portion of the projecting portion 41.

  By providing the projecting portion 41, heat conducted from the heating container 51 to the connecting member 30 can be reduced using the projecting portion 41. For this reason, the temperature of the upper end side (connecting member 30 side) of the protrusion 41 is lowered, and a high temperature does not act on the connecting member 30. Accordingly, it is possible to prevent the sealing performance between the cylindrical MEA 7 and the connection member 30 from being lowered. Further, high heat resistance is not required for the connection member 30 and the gas introduction pipe 45 connected thereto, so that the connection reliability is increased and the manufacturing cost can be reduced. In the present embodiment, the connection member 30 formed of a fluororesin is employed, and the protrusion length of the protrusion 41 is set such that the temperature at the tip of the protrusion is equal to or lower than the heat resistant temperature of the fluorine resin, for example, 205 ° C. or less. Is set.

  A cooling means 71 for forcibly cooling the protruding portion 41 can also be provided. For example, a fan or the like that sends cooling air to the protrusion 41 can be provided. In addition, a cooling conduit through which cooling water flows may be provided around the protrusion 41. By providing the cooling means 71, the cooling efficiency of the protruding portion 41 is increased, and the protruding length of the protruding portion 41 can be shortened. Therefore, the gas decomposition apparatus 100 can be reduced in size.

  Further, by providing the protrusion 41, the heat conducted to the connection member 30 can be greatly reduced. Thereby, the connection member 30 can be formed from a resin material. The kind of the resin material is not particularly limited. For example, it is preferable to employ a fluororesin having high heat resistance. By forming the connecting member from a resin material, it becomes possible to easily perform processing and the like, and the manufacturing cost can be reduced.

  In the connection member 30, the O-ring 33 housed on the inner surface side of the fastening portion 31 b extending from the main body portion 31 to the solid electrolyte layer 1 is in contact with the outer surface of the ceramic solid electrolyte layer 1 that is a fired body. Connected with. The fastening portion 31b of the connection member 30 has an outer diameter that is tapered, and a screw is cut there, and an annular screw 32 is screwed into the screw. By screwing in the direction in which the outer diameter of the annular screw 32 is increased, the fastening portion 31b is fastened from the outer surface, and the airtightness by the O-ring 33 can be adjusted. By forming the protrusion 41, the temperature acting on the O-ring 33 can be lowered, the life of the O-ring 33 can be extended, and the reliability of the seal structure can be increased.

  An engagement groove 81 is formed in the outer peripheral portion on the upper end side of the connection member 30, and a plate-like holding member 82 is engaged with the engagement groove 81. The holding member 82 is connected to a structural member (not shown), and the cylindrical MEA 7 is held so as to be suspended by the connecting member 30 with its axis oriented in the vertical direction.

  By holding the cylindrical MEA 7 as described above, a bending moment does not act on the cylindrical MEA 7. For this reason, stress is not concentrated on a part of the cylindrical MEA, and damage to the cylindrical MEA can be prevented. The orientation angle of the cylindrical MEA is not particularly limited, but is preferably configured to be held via the protruding portion or the connecting portion with the axis oriented in the vertical direction. A holding member for holding the cylindrical MEA can also be provided in the heating container.

Further, when ammonia decomposition is performed using the inside of the cylindrical MEA 7 as an anode, the oxygen ion conductive solid electrolyte is a reaction that generates water inside the cylindrical body (anode). Water drops are formed on the upper inner peripheral surface of the protrusion having a low temperature or the inner peripheral surface of the connection member 30. In this embodiment, since the shaft is oriented in the vertical direction and the cylindrical MEA 7 is held, the generated water droplets are dropped downward. Since the lower part of the cylindrical MEA 7 is maintained at a high temperature, the water droplets are vaporized to become water vapor and do not stay in the connection member 30 or the exhaust pipe 65. Therefore, no pressure loss occurs.

  Inside the connection member 30, a fitting portion 36 is formed in which the base end portion 11 d of the gas guiding pipe 11 k can be fitted with airtightness. As a result, the gas guiding pipe 11k and the connecting member 30 are connected to form a first gas passage.

  The connection member 30 is provided with a gas introduction part 31a for connection with the gas introduction pipe 45 for the first gas. By fitting the end portion of the gas introduction pipe 45 to the outer periphery of the gas introduction portion 31 a of the connection member 30 and fastening with the fastener 47, a good airtight connection can be obtained. The first gas flows from the gas introduction pipe 45 through the gas introduction part 31a into the gas induction pipe 11k. The first gas that has flowed into the gas induction pipe 11k flows through the internal space 42 to the vicinity of the sealing portion 44 of the cylindrical MEA 7.

  Further, the connection member 30 is provided with a gas discharge part 31 c for connecting to the exhaust pipe 65. By fitting the end portion of the gas exhaust pipe 65 to the outer periphery of the gas discharge portion 31 c of the connection member 30 and fastening with the fastener 67, a connection with good airtightness can be obtained. The first gas that has passed through the cylindrical MEA 7 is discharged to the exhaust pipe 65 through the exhaust space 35 and the gas discharge portion 31 c in the connection member 30.

  By adopting the connection member 30, the first gas is allowed to enter and exit from the same one side position of the cylindrical MEA 7 without mixing the first gas before decomposition and the first gas after decomposition. It becomes possible.

  The main body portion 31 of the connection member 30 is provided with a conductive through portion 37c that penetrates the main body portion 31 while maintaining airtightness, and is coated with a sealing resin 38 or the like in order to maintain airtightness. The conductive penetrating portion 37c is a cylindrical rod, and a screw for screwing the nut 39 is preferably cut in order to make a reliable conductive connection with the external wiring 11e. A conductive wire 37b is joined to the distal end of the conductive through portion 37c in the tube, and the other end 37a of the conductive wire 37b is joined to the outer peripheral portion of the gas induction pipe 11k via an annular fastening tool 34. .

  By adopting the above configuration, the connection resistance between the gas induction pipe 11k and the external wiring 11e can be reduced.

  On the other hand, external wiring 12e can be circulated around the outer periphery of the end portion of the Ni mesh sheet 12a of the cathode-side current collector 12, thereby leading to the outside. Since the second electrode layer (cathode) 5 is located on the outer surface side of the cylindrical MEA 7, it is not as difficult as withdrawing from the anode current collector 11 to the outside.

  As shown in FIG. 4, the connection between the anode-side current collector 11 and the external wiring 11 e and the connection member 30 with the gas introduction pipe 45 and the gas exhaust pipe 65 can be made in a small space. In addition, the above connection is made on the distal end side of the protruding portion 41. In other words, it is performed at a position deviating from the main flow portion of the heat flow from the heater 52. For this reason, even if the connection member 30 is formed of a heat-resistant resin such as a fluororesin, it is possible to ensure long-term repeated durability.

  In the present embodiment, a silver paste coating layer 11g is provided as a porous conductive layer on the inner peripheral portion of the first electrode layer (anode) 2, and a silver paste in which the Ni mesh sheet 11a is the porous conductive layer. It is connected to the first electrode layer 2 via the coating layer 11g.

A silver paste that becomes porous after being applied and dried (fired) is commercially available, and for example, DD-1240 manufactured by Kyoto Elex Co., Ltd. can be used. By making the silver paste coating layer 11g porous, many ammonia molecules NH ₃ enter the porous pores and come into contact with the catalyst in the first electrode layer (anode) 2 to cause an anodic reaction. It becomes easy.

  In order to increase the efficiency of the gas decomposition reaction, the porosity of the silver paste coating layer 11g is preferably set to 20 to 80%. When the porosity is 20% or less, it becomes difficult to guide the gas into the conductive paste coating layer, and the efficiency cannot be increased. On the other hand, when the porosity is 80% or more, it is difficult to ensure sufficient conductivity and the strength of the coating layer cannot be ensured. Furthermore, it is more preferable to set the porosity to 40 to 60%.

  The thickness of the silver paste coating layer 11g can be set to 5 to 300 μm. If it is 5 μm or less, the entire area of the Ni mesh sheet 11a cannot be uniformly brought into contact with the silver paste coating layer 11g, and it is difficult to ensure sufficient conductivity. On the other hand, when the thickness is 300 μm or more, it is difficult to form a paste coating layer having a sufficient porosity. In order to ensure conductivity and porosity, it is more preferable to provide a silver paste coating layer 11g having a thickness of 5 to 100 μm.

  The method for forming the silver paste coating layer 11g is not particularly limited. The silver paste coating layer 11g can be formed by a dipping method in which the cylindrical MEA 7 is immersed in an immersion layer filled with a silver paste, a technique of inserting a coating nozzle for spraying the silver paste on the inner surface of the cylindrical MEA 7, or the like. .

  Further, the method for forming the silver paste coating layer 11g to be porous is not particularly limited. In order to ensure the required porosity described above, a silver paste containing a predetermined amount of a binder that disappears at a predetermined temperature can be employed. In order to prevent shrinkage of the conductive paste coating layer when the binder disappears, it is preferable to add a sublimation binder. For example, it is preferable to employ a silver paste containing a naphthalene binder.

  The range in which the silver paste coating layer 11g is provided is not particularly limited, but the silver paste coating layer 11g is preferably provided on the entire surface of the first electrode layer (anode) 2. By forming the silver paste coating layer 11g on the entire surface of the first electrode layer (anode) 2, even when a part of the Ni mesh sheet 12a is separated from the silver paste coating layer 11g, the first electrode layer ( The current collecting performance in the anode 2 is not reduced.

  As the powder material constituting the solid electrolyte layer 1, a solid oxide, molten carbonate, phosphoric acid, solid polymer, or the like can be used. Solid oxides are preferred because they can be miniaturized and are easy to handle. Examples of the solid oxide include oxygen ion conductive SSZ (scandium stabilized zirconia), YSZ (yttrium stabilized zirconia), SDC (samarium stabilized ceria), LSGM (lanthanum gallate), GDC (gadria stabilized ceria), and the like. Should be used. Proton conductive barium zirconate can also be used. Each said powder material can be baked by hold | maintaining at 1000 degreeC-1600 degreeC for about 30 minutes-180 minutes by air | atmosphere atmosphere.

  The first electrode layer (anode) 2 can be formed as a fired body mainly composed of a metal particle chain having an oxidized layer that is surface oxidized and an oxygen ion conductive ceramic. As oxygen ion conductive ceramics, SSZ (scandium stabilized zirconia), YSZ (yttrium stabilized zirconia), SDC (samarium stabilized ceria), LSGM (lanthanum gallate), GDC (gadria stabilized ceria), etc. should be used. Can do.

  When adopting the above SSZ, it is preferable to use one having an average diameter of about 0.5 μm to 50 μm. The firing step can be performed by holding at 1000 ° C. to 1600 ° C. for about 30 minutes to 180 minutes in an air atmosphere. The average diameter of the raw material powder of SSZ is preferably about 0.5 μm to 50 μm. The compounding ratio of the surface-oxidized metal particle chain and SSZ is in the range of 0.1 to 10 in terms of molar ratio.

  The metal of the metal particle chain is preferably nickel (Ni) or one containing Ni (Fe) in Ni. More preferably, it contains a very small amount of titanium (Ti) of about 2 to 10000 ppm.

  The metal particle chain is preferably produced by a reduction precipitation method. The reduction precipitation method for this metal particle chain is described in detail in JP-A No. 2004-332047. The average diameter D of the metal particle chain contained in the first electrode layer (anode) 2 is preferably in the range of 5 nm to 500 nm. The average length L is preferably in the range of 0.5 μm or more and 1000 μm or less. The ratio between the average length L and the average diameter D is preferably 3 or more. However, it may have dimensions outside these ranges.

  The second electrode layer (cathode) 5 is formed from a fired body mainly composed of oxygen ion conductive ceramics. As the oxygen ion conductive ceramic in this case, LSM (lanthanum strontium manganite), LSC (lanthanum strontium cobaltite), SSC (samarium strontium cobaltite), or the like can be used. These powder materials can also be fired under the same conditions as described above.

  5 to 7 show a second embodiment of the present invention. The second embodiment is configured by providing a protruding member 241 corresponding to the protruding portion 41 according to the first embodiment. Note that the configurations of the cylindrical MEA 207, the heating container 251 and the like are the same as those in the first embodiment, and thus description thereof is omitted.

  As shown in FIG. 5, in 2nd Embodiment, the flange part 251a which can hold | maintain the said cylindrical MEA207 is provided in the wall part of the said heating container 251 by which the said cylindrical MEA207 is penetrated. The cylindrical MEA 207 is attached to the flange portion 251a in a state in which a part thereof extends to the outside of the heating container 251. The inner peripheral portion of the flange portion 251a is filled with a heat-resistant sealing material, and the airtightness between the outer peripheral portion of the cylindrical MEA 207 and the inner peripheral portion of the flange portion 251a is ensured. Is retained.

  A cylindrical projecting member 241 extending in the axial direction of the cylindrical MEA 207 is provided on the outer surface side of the wall portion provided with the flange portion 251a. The projecting member 241 accommodates the extending portion 207b of the cylindrical MEA 207 with airtightness, and a fluororesin connecting member 230 is connected to the distal end side.

  A flange portion 241 a is formed on the heating container side of the protruding member 241, and is fixed to the wall portion of the heating container by screw means 261. A heat-resistant gasket (not shown) is interposed between the flange portion 241a and the outer surface of the heating container 251 so that airtightness between the protruding member 241 and the heating container 251 is ensured, and a tubular shape. The gas flowing in the MEA is configured not to leak. In the present embodiment, the cylindrical MEA 207 is held in a state where the axis is oriented in the vertical direction by the flange portion 251a of the heating container 51 and the protruding member 241.

  On the other hand, the front end portion 241b of the protruding member 241 is fitted with a fitting portion 236 provided on the connecting member 230 with airtightness.

  The protruding member 241 can be formed using various materials as long as the temperature acting on the connecting member 230 can be reduced. For example, the connecting member can be formed from a heat-resistant and heat-insulating material such as ceramic. Further, by forming from a metal material such as nickel having high heat dissipation, the heat conducted from the cylindrical MEA 207 is dissipated in the protruding member 241 so that the temperature acting on the connecting member 230 is reduced. It can also be configured.

  In the present embodiment, an annular convex portion 281 is formed on the outer periphery of the intermediate portion of the protruding member 241, and the annular convex portion 281 is locked to the edge portion of the engagement hole 282 a provided in the plate-like holding means 282. Thus, the gas decomposition element 210 is held through the protruding member 241 with the axis oriented in the vertical direction. By adopting this configuration, a bending moment does not act on the cylindrical MEA 7, and damage due to stress concentration or the like can be prevented.

  The holding means 282 is formed in a plate shape that partitions the space between the connection member 230 and the heating container 251. By adopting this configuration, the holding means 282 can block the convection heat and radiant heat from the high temperature region of the heating container 251 and the protruding portion. Therefore, it is possible to mitigate an increase in the temperature of the connecting member 230.

  Similarly to the first embodiment, the protruding member 241 is provided with a conductive through portion (not shown) that penetrates while maintaining airtightness, and extends from the outer peripheral portion of the gas induction pipe 211k constituting the first current collector. The connection wiring 211e extends to the outside of the protruding member 241. Further, the connection wiring 212e extending from the second current collector provided on the outer peripheral portion of the cylindrical MEA 207 is also extended from the protruding member 241 as described above.

  By adopting the above configuration, the temperature acting on the connection wirings 211e, 212e and the like can be greatly reduced. Further, since almost the entire cylindrical MEA 207 involved in the gas decomposition reaction can be accommodated in the heating container 251, it is possible to increase the gas decomposition efficiency by applying a uniform temperature to the cylindrical MEA.

  Furthermore, by employing the protruding member 241, the cooling means 271 can be easily provided. For example, as shown in FIG. 5, it is possible to integrally form the radiating fins 271 a on the protruding member 241. Moreover, piping which employ | adopts cooling air or cooling water can also be provided integrally. Therefore, by employing the protruding member 241, the temperature acting on the connecting member 230 can be significantly reduced.

  FIG. 6 is an overall longitudinal sectional view of the gas decomposition apparatus 200 including the gas decomposition element 210 shown in FIG. FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.

  In the present embodiment, the heater 252 is provided on the outer peripheral portion of the heating container 251. The gas decomposition apparatus 200 is configured by arranging a plurality of gas decomposition elements 210 as a group in parallel and three-dimensionally. The gas decomposition elements 210 are arranged in a heating container 251 including a heater 252 and are held at a predetermined temperature in the heating container 251.

  Protruding members 241 corresponding to the respective gas decomposition elements 210 are provided on the side walls of the heating container 251, and connecting members 230 are connected to the respective front ends thereof.

  The projecting members 241 are held in an array by engaging annular projections 281 provided on the outer periphery with engagement holes 282 provided in the plate-like holding means 282. The plate-like holding means 282 is configured to partition the space in which the protruding member 241 is arranged so that heat due to convection and radiation from the heating container 251 does not act on the connection member. Therefore, the temperature rise of the connection member 230 can be effectively prevented using the holding means 281.

  By adopting the above configuration, each gas decomposition element 210 can be heated to the same temperature. Moreover, it can be made to act on a several gas decomposition | disassembly element by flowing 2nd gas in the said heating container. Therefore, the gas decomposition apparatus 200 can be reduced in size.

  In the above-described embodiment, the present invention is applied to a gas decomposition apparatus for the purpose of removing gas. However, the present invention can be applied to a gas decomposition apparatus that is not mainly used for removing gas and a cylindrical MEA of an electrochemical reaction apparatus. For example, it can also be used for a cylindrical MEA that constitutes a power generator such as a fuel cell.

  The embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  Not only is the gas decomposition performance high, but a high temperature does not act on the connecting member and the external piping, and a highly reliable gas decomposition apparatus and power generation apparatus can be provided.

DESCRIPTION OF SYMBOLS 1 Solid electrolyte layer 2 1st electrode layer (anode)
5 Second electrode layer (cathode)
7 Tubular MEA
DESCRIPTION OF SYMBOLS 10 Gas decomposition element 11 Anode side collector 11a Ni mesh sheet 11d Base end part 11e External wiring 11g Silver paste application layer 11k Gas induction pipe 11s Porous metal body 12 Cathode side current collector 12a Ni mesh sheet 12g Silver paste application wiring 12e External wiring 30 Connection member 31 Main body 31a Gas introduction part 31b Fastening part 31c Gas discharge part 32 Annular screw 33 O-ring 34 Fastener 35 Exhaust space 36 Fitting part 37a Other end part 37b Conductive wire 37c Conductive through part 38 Sealing Resin 39 Nut 41 Projection part 42 Internal space 43 Cylindrical flow path 44 Sealing part 45 Gas introduction pipe 47 Fastener 51 Heating vessel 52 Heater 53 Preheating pipe 65 Exhaust pipe 81 Engaging groove 82 Plate-like holding means 100 Gas decomposition device S space W ₁ Ni mesh sheet Tip W ₂ joint member

Claims (13)

Cylindrical MEA having a cylindrical solid electrolyte layer, a first electrode layer formed on the inner periphery of the solid electrolyte layer, and a second electrode layer formed on the outer periphery of the solid electrolyte layer A gas decomposition apparatus configured using (Membrane Electrode Assembly),
A heating vessel that houses and heats the tubular MEA;
A sealing portion disposed in the heating container, the sealing member being disposed at one end of the cylindrical MEA;
A gas induction pipe that is inserted into the inner space of the cylindrical MEA and forms a cylindrical flow path between the inner peripheral surface of the cylindrical MEA;
A protrusion that is provided continuously to the cylindrical MEA and protrudes from the heating container;
A connecting member provided at an opening end of the protruding portion;
Holding means for holding the cylindrical MEA in a posture in which the axis is oriented in the vertical direction ;
A preheating pipe that preheats a gas that passes through the heating vessel and is guided to the gas induction pipe;
The connecting member is provided with a gas inlet communicating with the gas conducting pipe surrounds the outer periphery of the gas guiding pipe, which is configured with an exhaust annular space having a gas outlet on the side, the gas Disassembly equipment.   The gas decomposition apparatus according to claim 1, further comprising the holding unit that holds the cylindrical MEA via the protruding portion or the connection member.   The gas decomposition apparatus according to claim 1, further comprising the holding unit that holds the cylindrical MEA via the heating container. The cylindrical MEA is
A lower end portion is provided while being sealed, and a sealing portion disposed in the heating container;
A gas induction pipe which is inserted into the inner space of the cylindrical MEA and forms a cylindrical flow path with the inner peripheral surface of the cylindrical MEA;
By causing the gas introduced into the gas induction pipe through the connection member provided at the upper end portion to flow toward the sealing portion and outflowing from the induction pipe in the vicinity of the sealing portion. The flow is reversed, and the cylindrical flow path is made to act on the first electrode layer while flowing in the direction opposite to the flow in the gas induction pipe, and is decomposed and discharged through the connection member. The gas decomposition apparatus according to any one of claims 1 to 3.   The gas decomposition apparatus according to any one of claims 1 to 4, wherein the protruding portion is configured by causing a part of the cylindrical MEA to protrude from the heating container.   The gas decomposition apparatus according to any one of claims 1 to 5, wherein a part or all of the protruding portion is formed of a member separate from the cylindrical MEA. The holding means is configured to hold the cylindrical MEA via the protrusion,
The gas decomposition apparatus according to any one of claims 1 to 6, wherein the gas decomposition apparatus is formed in a plate shape capable of shielding the convection heat and radiant heat from the heating container from acting on the connection member.   The gas decomposition apparatus according to any one of claims 1 to 7, wherein a cooling means for cooling the protrusion is provided.   The gas decomposition apparatus according to any one of claims 1 to 8, wherein a temperature at a tip of the protruding portion is set to 205 ° C or lower.   The gas decomposition apparatus according to any one of claims 1 to 9, wherein the connection member is formed of a resin material. The first electrode layer and / or the second electrode layer is a fired body including a metal particle chain composed mainly of nickel (Ni) and an ion conductive ceramic. The gas decomposition apparatus according to any one of claims 1 to 10 . The gas decomposition apparatus according to any one of claims 1 to 11 , wherein the solid electrolyte layer has oxygen ion conductivity or proton conductivity. A power generator comprising the gas decomposition apparatus according to any one of claims 1 to 12 .

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