JP5703762B2 - 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.

  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 above.

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 decomposing apparatus configured using a tubular MEA (Membrane Electrode Assembly) having a heating container that houses and heats the tubular MEA, and is provided continuously with the tubular MEA and the heating A projecting portion projecting from the container, a connecting member provided at the opening end of the projecting portion, and a sealing portion disposed in the heating container while sealing one end of the cylindrical MEA And a gas induction pipe that is inserted into the inner space of the cylindrical MEA and forms a cylindrical flow path between the inner circumferential surface of the cylindrical MEA and the protrusion or the connection member, this Site of temperature, or a temperature sensor the temperature can the measurement of exhaust gas flowing these sites, the protrusions or the temperature of the connecting member, or controlled so that the temperature is equal to or less than a predetermined temperature of the exhaust gas flowing through these parts The connecting member includes a gas introduction portion communicating with the gas induction pipe, and an annular exhaust space that surrounds the outer periphery of the gas induction pipe and has a gas discharge portion on a side portion thereof. It is configured .

  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. And the piping which supplies or discharges the gas which flows through the inside of cylindrical MEA is provided through the said connection member. In other words, in the present invention, the connecting member is provided outside the heating container at a position away from the heating container, and acts to perform piping. With this configuration, the amount of heat conducted from the cylindrical MEA in the heating container to the connecting member and the pipe is reduced, and the temperature of the connecting member and the pipe is lowered.

  However, when the gas flow rate is increased in order to improve the gas decomposition performance, not only the amount of heat conducted through the protruding portion is increased, but also the gas that has reached a high temperature in the heating vessel is converted into the cylindrical MEA. There is a risk of damaging these members by directly acting on the sealing structure between the connecting members and the connecting members, the piping for discharging the gas, and the like.

In this invention, while providing in the said protrusion part or the said connection member, the temperature sensor which can measure the temperature of these parts or the temperature of the exhaust gas which flows through these parts is provided, and it comprises so that the temperature of these parts may be monitored. ing. And the control means which controls so that the temperature of the said protrusion part or the said connection member , or the temperature of the exhaust gas which flows through these parts becomes below predetermined temperature is provided.

The said control means is provided in order to control so that the temperature of the said site | part may become below predetermined temperature, and can be comprised including various structures. For example , the control means includes a heater control device for the heating container, and when the temperature measured by the sensor exceeds a predetermined temperature, the temperature of the heating container is lowered or the heating is stopped. It can be constituted as follows.

Moreover , the said control means can be comprised including the cooling means which can cool the said protrusion part and / or the said connection member. The configuration of the cooling means is not particularly limited, and a device for flowing cooling air or cooling water can be provided around the protruding portion and the connecting member.

Furthermore , the control means may be configured to include a cooling means capable of cooling the gas flowing in the protrusion or the connection member. For example, a cooling fin and a cooling water circuit capable of cooling the fin can be provided in the protrusion, and the gas flowing in the protrusion and the connection portion can be cooled.

  The said control temperature can be set with the heat resistant temperature etc. of a seal structure, a connection member, piping, etc. For example, when a fluororesin is employed as the connecting member, when the heat resistant temperature of 205 ° C. is exceeded, heating by the heater is stopped by the control means and the cooling means is operated. .

By adopting the above configuration, it is possible to reliably prevent the sealing structure between the cylindrical MEA and the connection member and the connection member from being damaged by heat. Moreover, 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.

  In addition, by adopting the above configuration, high heat resistance is not required for the connection member and piping connected to the connection member, so that connection reliability is increased and manufacturing cost can be reduced.

Further, the gas flow path in the connecting member, heat thus the connecting member which acts from the flowing gas can kick optional protective member to prevent damage.

  When the high-temperature gas flows in the connecting member, heat is conducted from the high-temperature gas to the inner surface of the flow path, and a part of the flow path may locally become high temperature. By providing the protective member in the gas flow path, it is possible to protect the surface of the flow path and to prevent the local area of the connection member from being exposed to high temperatures.

  The configuration and form of the protective member are not particularly limited. For example, the said protection member can be provided by apply | coating the heat resistant ceramic heat-resistant coating material to the inner surface of a connection member. In addition, for example, by providing a metallic sheet metal member that constitutes a part of the flow path in a portion where the temperature of the gas is easy to conduct, it is possible to prevent heat from diffusing and to increase the local temperature. .

Upper Symbol cylindrical MEA, together provided to seal the lower end, and a sealing portion which is arranged in the heating vessel, is inserted into the inner space of the tubular MEA, the inner periphery of the tubular MEA A gas guide pipe that forms a cylindrical flow path between the gas guide pipe and the gas introduced into the gas guide pipe through the connection member provided at the upper end portion 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 MEA can be held by being suspended by holding means provided above the heating container, and can be held without applying a moment due to its own weight to the cylindrical MEA. For this reason, damage to the cylindrical MEA can be prevented and 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 may include a gas introduction portion communicating with the gas induction pipe, and 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.

The configuration of the protruding portion is not particularly limited . The protruding portion can be configured by protruding a part of the cylindrical MEA 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.

  In particular, when the protruding portion is formed of a separate member from the cylindrical MEA, the cooling means can be integrally formed with the protruding portion.

  The materials constituting the first electrode layer and the second electrode layer are not particularly limited. For example, as in the invention described in claim 10, the first electrode layer and / or the second electrode layer is formed of a metal particle chain mainly composed of nickel (Ni), an ion conductive ceramic, It can be set as the sintered body containing this. 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 moved in the solid electrolyte layer to be the first electrode. A predetermined electrochemical reaction can be caused in the 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 the second electrode layer ( To the cathode) and 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.

The gas decomposition method performed using the gas decomposition apparatus according to the present invention measures the temperature of the protruding portion or the connecting member, or the temperature of exhaust gas flowing through these portions, and the temperature of these portions is a predetermined temperature. The gas decomposition is performed while controlling to be as follows.

  Invention of Claim 13 is a gas decomposition method performed using the gas decomposition apparatus of any one of Claims 1-12, Comprising: The temperature of the said protrusion part or the said connection part, or While measuring the temperature of the gas which flows through these parts, and controlling so that the temperature of these parts may become below predetermined temperature, it decomposes | disassembles gas.

  The inside of the cylindrical MEA can be maintained at a high temperature to increase gas decomposition efficiency, and the seal structure and piping members are prevented from being damaged by heat. Further, these members are made of an inexpensive material having low heat resistance. Can be configured.

It is a figure which shows schematic structure of the gas decomposition apparatus which concerns on this invention. 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 III-III 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 sectional drawing which follows the VII-VII line in FIG. It is sectional drawing of the principal part which shows 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 is a diagram showing a schematic configuration of a gas decomposition apparatus 100 according to a first embodiment of the present invention.

  In the first embodiment, a gas decomposition apparatus 100 is configured by housing a plurality of gas decomposition elements 10 each including a cylindrical MEA 7 in a heating container 51.

  The cylindrical MEA 7 is provided with a protruding portion 41 by accommodating the lower portion in the heating container 51 and causing the upper portion to protrude upward from the heating container. A connecting member 30 is provided at the opening end of the upper end of the cylindrical MEA 7, and a gas containing gas to be decomposed into the cylindrical MEA is introduced through the connecting member 30, and after the decomposition. The exhaust is exhausted.

  The heating container 51 is provided with a heater 52. By operating the heater 52, the cylindrical MEA 7 and the first and second gases that act on the cylindrical MEA 7 are heated. ing. The heater 52 is configured to be controlled by the control device 72 and configured to be able to maintain the inside of the heating container 51 at a predetermined temperature, for example, 700 to 900 ° C.

  In the present embodiment, a cooling means 71 for cooling the protrusion 41 and the connecting member 30 is provided, and the operation can be controlled by the control device 72. In the present embodiment, the control device 72 is configured to include a function of controlling the operation of the heater 52 and the cooling means 71. However, a drive control device for directly driving and controlling the heater 52 and the cooling means is separately provided. These drive control devices can also be configured to be controlled by the control device 72.

  Further, the connection member 30 is provided with a sensor 73 capable of measuring the temperature of the exhaust gas flowing in or near the connection member 30. In the present embodiment, the sensor 73, the heater 52, the cooling means 71, and the control device 72 constitute the control means 70 for controlling the temperature of the portion where the sensor 73 is provided or the temperature of the gas flowing in the vicinity thereof. Has been.

  FIG. 2 is a longitudinal sectional view showing the structure inside the heating container 51 in the gas decomposition apparatus 100. 3 is a cross-sectional view taken along line III-III 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.

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). The flow path inside the cylindrical MEA 7 (1, 2, 5) through which the first gas flows is used as the first gas flow path, and the cylindrical MEA 7 (1, 2, 5) through which the second gas flows. The space S in the heating container 51 outside 5) is used as the 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 of the cylindrical MEA 7 (1, 2, 5) and the first electrode layer 2 located on the inner side and providing a bottom portion. ing.

  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 is in contact with the outer surface of the cylindrical MEA 7 and conducts to the external wiring 12e shown in FIG. 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.

  A space S for flowing the second gas is provided in the heating container 51. The heater 52 is disposed on the outer periphery of the heating container 51. In the present embodiment, a preheating pipe 53 is disposed 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. The first gas is preheated by passing through the preheating pipe 53 before introducing the first gas into the cylindrical MEA 7, and the first gas having a low temperature is suddenly introduced into the cylindrical MEA 7. Eliminates 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 with a pipe from the first gas source, and the downstream side is configured to be connected to the gas introduction pipe 45 shown in FIG.
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.
Although one cylindrical MEA 7 and one preheating pipe 53 are provided for each gas decomposition element 10 in FIG. 3, gas is supplied to a plurality of gas decomposition elements 10 from one preheating pipe. You may comprise as follows. 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.
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.

FIG. 4 is a diagram showing an electrical wiring system of each gas decomposition element 10 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, a part of the electric power for that purpose can be supplied. it can.

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. , Protons are transferred to the second electrode layer (cathode) 5 through the solid electrolyte layer 1 and reacted 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. 5 is a longitudinal sectional view showing the structure of the upper part of the gas decomposition apparatus 100. The gas induction pipe 11k and the external wiring 11e are connected, and the cylindrical MEA 7, the gas introduction pipe 45, and the exhaust pipe 65 are connected. The form and the holding | maintenance form of the gas decomposition element 10 are shown.

  In the present embodiment, the heating container 51 accommodates the lower part of the cylindrical MEA 7 with the axis oriented in the vertical direction, and the upper end of the cylindrical MEA 7 protrudes above the heating container 51 and protrudes. A connecting member 30 for allowing gas to enter and exit is provided at the opening end at the upper end of the projecting portion 41.

  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 airtightness by the O-ring 33 can be secured.

  By providing the protrusion 41, a part of the heat conducted from the heating container 51 can be dissipated, and the heat conducted to the O-ring 33 and the connection member 30 can be reduced. For this reason, it can prevent that high temperature acts on the said seal structure or the said connection member 30 via the said cylindrical MEA.

  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.

  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.

  By providing the protrusion 41, heat conducted to the O-ring 33 and the connection member 30 can be reduced. However, if the flow rate of the gas flowing in the cylindrical MEA is increased in order to improve the gas decomposition performance, not only the temperature conducted through the protrusion 41 increases, but also the temperature inside the heating container 51 increases. The resulting gas may directly act on the sealing structure between the cylindrical MEA and the connecting member, the connecting member, and the piping for discharging the gas, thereby damaging these members.

  In order to avoid the inconvenience, the above-described control means 70 capable of adjusting the temperature acting on the connection member or the like is provided. As shown in FIG. 5, the control means 70 includes a temperature sensor 73 embedded in the inner peripheral surface of the exhaust space 35 of the connection member 30, a heater 52 that heats the heating container 51, and the protruding portion. 41 and a cooling means 71 for cooling the connecting member 30 and a control device 72 for controlling them.

  The sensor 73 is arranged so that the temperature of the gas exhaust space of the connecting member 30 can be measured. The sensor 73 measures the temperature acting on the surface of the exhaust space 35 of the connection member 30 from the temperature of the inner peripheral surface of the connection member 30 or the flowing gas.

  The control device 72 is configured to monitor the temperature of the connection member 30 by the sensor 73 and to control the heater 52 and the cooling means 71 so that the temperature of the connection member 30 is equal to or lower than a predetermined temperature. Has been.

  That is, when the temperature measured by the sensor 73 exceeds a predetermined temperature, the power supplied to the heater 52 is reduced to lower the temperature of the heating container 51 or to stop heating. ing. The said temperature can be set according to the heat resistance of the said connection member 30 or a seal structure. For example, when the sealing structure and the connecting member are formed using fluororesin, it is preferable to control the temperature measured by the temperature sensor 73 to be 205 ° C. or lower.

  The cooling means 71 is configured to operate when the temperature exceeds a predetermined temperature. For example, it is configured to operate when the temperature measured by the temperature sensor 73 exceeds 205 ° C. to cool the connecting member and the like.

  As the cooling means 71, for example, a fan or the like that sends cooling air to the protrusion 41 and the connection member 30 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. The heater 52 and the cooling means 71 are controlled so that the temperature of the connecting member 30 becomes a predetermined value or less.

  By providing the control means 70, it is possible to set the temperature acting on the seal structure and the connecting member 30 to a heat resistant temperature or lower. Thereby, while being able to prevent the sealing performance from being lowered, it is possible to prevent the connection member 30 from being damaged. 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. Furthermore, the connecting member 30 can be made to function as a safety device that avoids the risk of melting by heat.

  In the present embodiment, the control unit 70 includes both the heater 52 and the cooling unit 71. However, the control unit 70 may include only one.

  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. 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.

  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.

  6 and 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. 6, in 2nd Embodiment, the flange part 251a which can hold | maintain the said cylindrical MEA207 is provided in the upper 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 upper wall portion of the heating container 251 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 and the projecting member 241 is configured not to leak.

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

  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.

  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, a cooling means 271 that can cool not only the protruding member itself but also the gas flowing inside is provided at the intermediate portion of the protruding member 241. The cooling means 271 is integrally formed with the protruding member 241 and has a plurality of cooling fins 271a extending radially inward from the inner peripheral surface, and an outer periphery of a portion of the protruding member 241 where the cooling fins 271a are provided. And an annular cooling device 271b having a flow path 271c for flowing cooling water therein, and a pump 271d for circulating the cooling water through the flow path 271c. The cooling means 271 constitutes the control means 270 and is configured to be controlled by the control device 272, as in the first embodiment.

  On the other hand, the connection member 230 is provided with a temperature sensor 273 protruding into the exhaust space 235 in which the decomposed gas flows. The temperature sensor 273 is connected to the control device 272.

  As shown in FIG. 7, also in this embodiment, the operations of the heater 252 and the cooling means 271 are controlled by the output of the temperature sensor 273. In the second embodiment, the heater 252 and the cooling means 271 can be controlled by directly measuring the temperature of the gas flowing in the connection member 230. For this reason, the temperature of the connection member 241 or the seal structure does not rise locally. Therefore, the connection member 241 and the seal structure can be reliably protected.

  FIG. 8 shows a third embodiment of the present invention. In this embodiment, a protective member 390 is provided on the inner surface of the exhaust space 335 of the connecting member 330 to prevent the inner surface of the connecting member 330 from being damaged by heat acting from the flowing gas.

  When the high-temperature gas flows in the connecting member 330, heat may be directly conducted from the high-temperature gas to the inner surface of the flow path, and a part of the flow path may become locally hot. By providing the protective member in the gas flow path, the surface of the flow path can be protected. Therefore, it is possible to prevent the local area of the connection member 330 from being exposed to high temperatures.

The configuration and form of the protective member 390 are not particularly limited. For example, the protective member 390 can be provided by applying a heat-resistant ceramic heat-resistant paint to the inner surface of the connection member. Further, by providing a metallic sheet metal member constituting a part of the gas flow path on the surface of the portion where the gas temperature is easy to conduct, it is possible to prevent heat from diffusing and to locally increase the temperature.

  In the above-described embodiments, the present invention is applied to a gas decomposition apparatus for the purpose of gas abatement. However, the present invention can be applied to a gas decomposition apparatus not intended for a gas abatement 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 70 Control means 71 Cooling means 72 Control apparatus 73 Temperature sensor 81 engaging groove 82 plate-like holding means DESCRIPTION OF SYMBOLS 100 Gas decomposition apparatus S Space W ₁ Tip part of Ni mesh sheet W ₂ Joining member

Claims (13)

A cylindrical shape having a cylindrical solid electrolyte layer, a first electrode layer stacked on the inner periphery of the solid electrolyte layer, and a second electrode layer stacked on the outer periphery of the solid electrolyte layer A gas decomposition apparatus configured using MEA (Membrane Electrode Assembly),
A heating vessel that houses and heats the tubular 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;
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 temperature sensor that is provided on the protrusion or the connection member, and that can measure the temperature of these parts, or the temperature of exhaust gas flowing through these parts ,
Control means for performing control so that the temperature of the protruding portion or the connecting member, or the temperature of the exhaust gas flowing through these portions is equal to or lower than a predetermined temperature,
The connection member includes a gas introduction portion that communicates with the gas induction pipe, and includes an annular exhaust space that surrounds an outer peripheral portion of the gas induction pipe and includes a gas discharge portion on a side portion thereof. apparatus.   The control means includes a heater control device for the heating container, and when the temperature measured by the sensor exceeds a predetermined temperature, the temperature of the heating container is decreased or the heating is stopped. The gas decomposition apparatus according to claim 1, configured as described above.   The gas decomposition apparatus according to claim 1, wherein the control unit includes a cooling unit that can cool the protrusion and / or the connection member.   The gas decomposition apparatus according to any one of claims 1 to 3, wherein the control means includes a cooling means capable of cooling a gas flowing in the protrusion or the connection member. A gas flow path in the connecting member, heat thus the connecting member which acts from the flowing gas is a protective member to prevent damage, as claimed in any one of claims 4 Gas Disassembly equipment. 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 5. The gas decomposition apparatus according to any one of claims 1 to 6, wherein the protruding portion is configured by protruding a part of the cylindrical MEA from the heating container.   The gas decomposition apparatus according to any one of claims 1 to 6, wherein a part or all of the protruding portion is formed of a member separate from the cylindrical MEA.   The gas decomposition apparatus according to any one of claims 1 to 8, 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 9.   The gas decomposition apparatus according to any one of claims 1 to 10, 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 11. A gas decomposition method performed using the gas decomposition apparatus according to any one of claims 1 to 11,
While measuring the temperature of the protrusion or the connecting member , or the temperature of the exhaust gas flowing through these parts,
A gas decomposition method in which gas decomposition is performed while controlling the temperature of these parts to be equal to or lower than a predetermined temperature.

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