JP5725443B2 - Fuel cell module - Google Patents

Description

  The present invention relates to a fuel cell module, and more particularly to a fuel cell module that generates electric power using steam-reformed fuel.

  A solid oxide fuel cell (hereinafter also referred to as “SOFC”) uses an oxide ion conductive solid electrolyte as an electrolyte, has electrodes attached to both sides thereof, supplies fuel gas on one side, and supplies the other This is a fuel cell device that generates power by supplying an oxidant (air, oxygen, etc.) to the side of the tube and generating a power generation reaction at a relatively high temperature.

  More specifically, this fuel cell apparatus (SOFC) includes a plurality of fuel cell cells that operate when fuel gas and oxidant (air, oxygen, etc.) flow from one end side to the other end side. After being supplied with reformed gas (city gas, etc.) as fuel from outside, the city gas is introduced into a reformer containing a reforming catalyst, and reformed into hydrogen-rich fuel gas Supplying to a plurality of fuel cells.

  On the other hand, in a fuel cell device, steam reforming is performed by a reformer to generate fuel gas. However, Patent Document 1 discloses that the water is steamed by an evaporator to be steamed and reformed together with the reformed gas. A fuel cell device is described in which fuel gas is generated by supplying steam to the reformer and performing steam reforming in the reformer.

  Further, in Patent Document 2, water and a gas to be reformed are supplied to a vaporizing chamber (evaporator) provided in a part of the reforming vessel, and water is evaporated in the vaporizing chamber, whereby the gas to be reformed A reforming apparatus is described that supplies a necessary amount of water vapor for reforming.

JP 2008-147200 A JP 2008-7349 A

  However, in the above-described conventional fuel cell device (Patent Document 1), the corrosion resistance of the path for supplying the steam generated by the evaporator to the reformer may be a problem. That is, when high-temperature steam is supplied to the reformer through a metal pipe, the pipe may be corroded.

  On the other hand, as described in Patent Document 2, if water or water vapor is mixed with the gas to be reformed, corrosion of the pipe can be reduced as compared with a case where only water vapor is supplied to the reformer through the pipe. However, in such a case, it may be difficult to stably supply the reformed gas to the evaporator. That is, in the evaporator, a large amount of water vapor is suddenly generated due to bumping of water, etc., and the water vapor partial pressure in the evaporator rises abruptly, so that the gas to be reformed cannot flow into the evaporator. There is a problem that it becomes impossible to supply the reformed gas.

  Therefore, the present invention has been made to solve the problems of the prior art, and while mixing steam and reformed gas in an evaporator to prevent corrosion of the pipe, It aims at providing the fuel cell module which can be stably supplied to an evaporator.

  In order to achieve the above-described object, the present invention performs power generation by receiving a reformer that generates a fuel gas by steam reforming a gas to be reformed, and a supply of the fuel gas generated by the reformer. A fuel cell module having a fuel cell, an evaporator that has a heating container that heats water therein, and that generates steam to be used in the reformer, and a gas to be reformed is supplied into the heating container The reformed gas supply pipe and the water supply pipe for supplying water into the heating container are provided, and the reformed gas supply pipe and the water supply pipe are the same space in the heating container and have a number of granular shapes. The body is connected to communicate with a buffer space in which the body is accommodated.

  In the present invention configured as described above, even if the water vapor partial pressure suddenly rises due to the bumping of water supplied from the water supply pipe to the buffer space in the heating container of the evaporator, it is accommodated therein. The granular material that becomes a buffer acts as a buffer material, and the influence on the reformed gas supply pipe is mitigated. Accordingly, it is possible to prevent a situation in which the supply of the reformed gas from the reformed gas supply pipe into the heating container is hindered by the increase in the partial pressure of water vapor in the heating container 15c, and the reformed gas is stably evaporated. Can be supplied to the vessel.

  In the present invention, preferably, at least one granule is disposed in a range where water is dropped from the water supply pipe on the bottom surface of the heating container.

  When the water dropped from the water supply pipe onto the bottom surface of the heating container of the evaporator becomes spherical, the surface area is small with respect to its volume, which may cause bumping and may take longer to evaporate and mix with the reformed gas. The situation that it becomes impossible to perform smoothly occurs. According to the present invention, the water dripped from the water supply pipe comes into contact with the granular material and spreads along the surface, thereby increasing the surface area and evaporating easily. Furthermore, it can supply stably to an evaporator, and can mix | blend water vapor | steam and to-be-reformed gas favorably.

  In the present invention, preferably, at least one tip of the water supply pipe and the reformed gas supply pipe is covered with a mesh member.

  In this invention comprised in this way, it can prevent by the mesh member that the granular material arrange | positioned in the buffer space is clogged with a water supply pipe and a to-be-reformed gas supply pipe. Therefore, the supply of water or the gas to be reformed to the buffer space can be made smooth, and water or water vapor and the gas to be reformed can be mixed more satisfactorily.

  In the present invention, preferably, one end portion of the water supply pipe and the to-be-reformed gas supply pipe is arranged to be positioned closer to the center portion of the heating container than the other end portion. At least one granule is disposed between the two.

  In the present invention configured as described above, even if the water supplied from the tip of the water supply pipe evaporates in the buffer space and the water vapor partial pressure rapidly increases, Due to the granular material disposed between them, the influence can be reliably mitigated, and the reformed gas can be stably supplied from the reformed gas supply pipe into the buffer space.

  According to the fuel cell module of the present invention, the fuel that can stably supply the gas to be reformed to the evaporator while mixing the steam and the gas to be reformed by the evaporator to prevent the corrosion of the piping. A battery module can be provided.

It is a perspective view showing a fuel cell module in the state where a cover member by one embodiment of the present invention was removed. It is sectional drawing which looked at the fuel cell module by one Embodiment of this invention from the A direction of FIG. It is sectional drawing which looked at the fuel cell module by one Embodiment of this invention from the B direction of FIG. It is a front view which shows the fuel cell unit of the fuel cell module by one Embodiment of this invention. It is a perspective view which shows the fuel cell stack of the fuel cell module by one Embodiment of this invention. It is a perspective view which shows the evaporator of the fuel cell module by one Embodiment of this invention. It is XX sectional drawing and YY sectional drawing of the evaporator shown in FIG. It is a figure which shows the mesh member used for the evaporator shown in FIG.

Hereinafter, a fuel cell module according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing a fuel cell module with a cover member removed according to an embodiment of the present invention, and FIG. 2 shows the fuel cell module according to an embodiment of the present invention as viewed from the direction A in FIG. 3 is a cross-sectional view, and FIG. 3 is a cross-sectional view of the fuel cell module according to the embodiment of the present invention as viewed from the direction B of FIG.

  The cover member (not explicitly shown in FIGS. 1 and 3, the outer shape of which is shown by a two-dot chain line in FIG. 2) includes a front side wall, a pair of longitudinal side walls, a back side wall, a ceiling, Is formed in a rectangular parallelepiped shape. A flange portion is formed at the lower end portion of each side wall, and a space sealed by the cover member and the base member 2 is formed by bringing the flange portion into contact with the base member 2. The cover member and the base member 2 are fixed by bolts (not shown), and the bolts pass through attachment holes provided in the cover member, and are fixed by passing through attachment holes 2a provided in the base member 2. ing.

  The internal space formed by the cover member and the base member 2 is separated into two spaces by the partition plate 15. Among the spaces separated by the partition plate 15, the space where the fuel cell stack 90, which is the fuel cell body, is disposed is the power generation chamber 16. Among the spaces separated by the partition plate 15, the other space is an exhaust gas chamber 17 (exhaust gas chamber). The inner wall surface of the cover member and the partition plate 15 are in close contact with each other directly or indirectly through some kind of contact member (for example, a flexible thin plate member).

  The partition plate 15 is placed on a support member 15 a provided on the base member 2 and is held at a predetermined distance from the base member 2. A pair of support members 15a are provided so as to support the partition plate 15 at both ends in the longitudinal direction. Accordingly, a gap 15b (inlet) is formed between the pair of support members 15a and 15a. Exhaust gas that has passed through an exhaust gas passage (not shown) provided on the wall surface of the cover member is introduced into the exhaust gas chamber 17 through the gap 15b. The exhaust gas introduced into the exhaust gas chamber 17 is exhausted from the exhaust port 11 (outlet) to the outside.

  The gas tank 3 is placed on the partition plate 15. In the gas tank 3, ten fuel cell stacks 90 serving as a fuel cell main body are arranged side by side, and fuel gas is supplied from the gas tank 3 to the fuel cell 4 constituting each fuel cell stack 90.

  More specifically, an opening (not shown) having substantially the same shape as the lower support plate 90b of the fuel cell stack 90 is provided on the upper surface of the gas tank 3, and the lower support plate 90b is in close contact with the opening. Thus, the gas tank 3 and each fuel cell stack 90 are connected. Accordingly, the fuel cells 4 constituting the fuel cell stack 90 are erected on the gas tank 3 with their tip portions facing upward.

  Each fuel battery cell 4 has a tubular shape, and a gas flowing from one end of the fuel battery cell 4 to the other end inside the pipe of the fuel battery cell 4 and outside the pipe from the one end to the other end. It operates by the action of the gas flowing to the part. In the present embodiment, the gas flowing in the pipe of the fuel battery cell 4 is a fuel gas such as reformed gas obtained by reforming hydrogen or hydrocarbon fuel, and the gas flowing outside the pipe of the fuel battery cell 4 contains oxygen. An oxidant gas (air for power generation) such as air.

  Next, the fuel cell unit 30 including the fuel cells 4 will be described with reference to FIG. FIG. 4 is a front view showing a fuel cell unit of a fuel cell module according to an embodiment of the present invention. As shown in FIG. 4, the fuel cell unit 30 is a tubular structure formed by the fuel cells 4 and extending in the vertical direction, and includes a cylindrical fuel cell 4 and one end of the fuel cell 4. It has an inner electrode terminal 40 attached to 4a, and an outer electrode terminal 42 attached to the other end 4b.

  The fuel cell 4 includes a cylindrical inner electrode layer 44, a cylindrical outer electrode layer 48, a cylindrical electrolyte layer 46 disposed between the electrode layers 44, 48, and an inner electrode. And a through flow channel 50 configured inside the layer 44. Further, an inner electrode exposed peripheral surface 44a in which the inner electrode layer 44 is exposed to the electrolyte layer 46 and the outer electrode layer 48 at one end 4a of the fuel cell 4, and the electrolyte layer 46 is an outer electrode layer. An electrolyte exposed peripheral surface 46 a exposed to 48 is provided. The other end 4b of the fuel cell 4 is configured by an outer electrode exposed peripheral surface 48a from which the outer electrode layer 48 is exposed. The through channel 50 functions as a fuel gas channel. The inner electrode exposed peripheral surface 44 a is also an inner electrode outer peripheral surface that is in electrical communication with the inner electrode layer 44. The outer electrode exposed peripheral surface 48 a is also an outer electrode outer peripheral surface that is in electrical communication with the outer electrode layer 48.

  The inner electrode layer 44 includes, for example, a mixture of Ni and zirconia doped with at least one selected from rare earth elements such as Ca, Y, and Sc, ceria doped with at least one selected from Ni and rare earth elements, And a mixture of Ni and lanthanum gallate doped with at least one selected from Sr, Mg, Co, Fe, and Cu. The electrolyte layer 46 includes, for example, zirconia doped with at least one selected from rare earth elements such as Y and Sc, ceria doped with at least one selected from rare earth elements, lanthanum gallate doped with at least one selected from Sr and Mg, Formed from at least one of the following. The outer electrode layer 48 is made of, for example, lanthanum manganite doped with at least one selected from Sr and Ca, lanthanum ferrite doped with at least one selected from Sr, Co, Ni, and Cu, Sr, Fe, Ni, and Cu. It is formed from at least one selected from lanthanum cobaltite doped with at least one selected from silver and silver. In this case, the inner electrode layer 44 becomes a fuel electrode, and the outer electrode layer 48 becomes an air electrode. The thickness of the inner electrode layer 44 is, for example, 1 mm, the thickness of the electrolyte layer 46 is, for example, 30 μm, the thickness of the outer electrode layer 48 is, for example, 30 μm, and the outer diameter is For example, it is 1-10 mm.

  The inner electrode terminal 40 is disposed so as to cover the inner electrode exposed peripheral surface 44a from the outside over the entire circumference and is electrically connected to the inner electrode terminal 40a. Part 40b. The main body portion 40a and the tubular portion 40b are cylindrical and concentrically arranged, and the tube diameter of the tubular portion 40b is smaller than the tube diameter of the main body portion 40a. The tubular portion 40b has a connection channel 40c that communicates with the through channel 50 and communicates with the outside. A step portion 40 d between the main body portion 40 a and the tubular portion 40 b is in contact with the end surface 44 b of the inner electrode layer 44.

  The outer electrode terminal 42 is disposed so as to cover the outer electrode exposed peripheral surface 48a from the outside over the entire circumference and is electrically connected thereto, and a tubular shape extending from the main body portion 42a in the longitudinal direction of the fuel cell 4. Part 42b. The main body portion 42a and the tubular portion 42b are cylindrical and concentric, and the tube diameter of the tubular portion 42b is smaller than the tube diameter of the main body portion 42a. The tubular portion 42b has a connection channel 42c that communicates with the through channel 50 and communicates with the outside. A step portion 42 d between the main body portion 42 a and the tubular portion 42 b is in contact with the outer electrode layer 48, the electrolyte layer 46, and the end surface 44 c of the inner electrode layer 44 via the annular insulating member 52.

  The overall shape of the inner electrode terminal 40 and the overall shape of the outer electrode terminal 42 are the same. Further, the inner electrode terminal 40 and the fuel battery cell 4, and the outer electrode terminal 42 and the fuel battery cell 4 are sealed and fixed by a conductive sealing material 54 over the entire circumference. The sealing material 54 is various brazing materials including, for example, silver, a mixture of silver and glass, gold, nickel, copper, and titanium.

  The connection flow path 40 c of the inner electrode terminal 40, the through flow path 50 of the fuel cell 4, and the connection flow path 42 c of the outer electrode terminal 42 constitute an in-pipe flow path 30 c of the fuel cell unit 30.

  Next, the fuel cell stack 90 including the fuel cell unit 30 will be described with reference to FIG. FIG. 5 is a perspective view showing a fuel cell stack of a fuel cell module according to an embodiment of the present invention. The fuel cell stack 90 includes 16 fuel cell units 30, an upper support plate 90a, a lower support plate 90b, a connection member 90c, and an external terminal 90d.

  The upper support plate 90a and the lower support plate 90b are rectangular, and are through holes (fitting holes) that fit into the tubular portions 40b and 42b of the fuel cell unit 30 so as to support the fuel cell unit 30 in 2 columns × 8 rows, respectively. (Not shown in the figure). The upper support plate 90a and the lower support plate 90b are formed of an electrically insulating material, for example, formed of heat resistant ceramics. Specifically, it is preferable to use alumina, zirconia, spinel, forsterite, magnesia, titania or the like.

  The 16 fuel cell units 30 are arranged so that they are electrically connected in series. Specifically, the fuel cell units 30 are arranged so that the inner electrode terminals 40 of the adjacent fuel cell units 30 are alternately arranged on the upper side and the lower side. Further, a connection member 90c for electrically connecting the 16 fuel cell units 30 in series is provided. The connection member 90 c electrically connects one adjacent inner electrode terminal 40 and one outer electrode terminal 42. Each of the inner electrode terminal 40 and the outer electrode terminal 42 at both ends of the 16 fuel cell units 30 connected in series is provided with an external terminal 90d for electrical connection with the outside. The connection member 90c and the external terminal 90d are made of, for example, a heat resistant metal such as stainless steel, a nickel base alloy, or a chromium base alloy, or a ceramic material such as lanthanum chromite. The external terminals 90d of each fuel cell stack 90 are electrically connected in series, and are connected to the electrode rods 13 and 14 at both ends thereof.

  As described with reference to FIGS. 4 and 5, in the fuel cell stack 90, the end 4 a of the fuel cell unit 30 where the inner electrode terminal 40 is provided and the end where the outer electrode terminal 42 is provided. The parts 4b are arranged so as to alternate with each other.

  Here, returning to FIGS. Further, in the following description, reference is also made to FIGS. 6 is a perspective view showing an evaporator of a fuel cell module according to an embodiment of the present invention, FIG. 7 is an XX sectional view and a YY sectional view of the evaporator shown in FIG. 6, and FIG. It is a figure which shows the mesh member used for the evaporator shown in FIG. As shown in FIG. 3, in this embodiment, the reformer 5 is disposed so as to be positioned above the fuel cell stack 90. The reformer 5 is connected to a pipe 6C (pipe) and a pipe 6D, and the pipe 6C and the pipe 6D allow the reformer 5 to move upward with a predetermined distance from the fuel cell stack 90. Is held in place. The pipe 6 </ b> C is a pipe for supplying city gas and water vapor as reformed gas to the reformer 5, and is erected with respect to the partition plate 15. The pipe 6 </ b> D is a pipe for supplying the fuel gas reformed in the reformer 5 to the gas tank 3, and is erected with respect to the gas tank 3.

  The evaporator 19 has a rectangular parallelepiped heating container 15c having a space inside, and a reformed gas supply pipe 6A and a water supply pipe 6B are connected to the side face 15c1, and each pipe line is connected to the inside of the heating container 15c. Communicate. As shown in detail in FIG. 7, the to-be-reformed gas supply pipe 6A is connected to the side surface 15c at a position where the tip 6A1 is substantially flush with the inner surface of the heating container 15c, while the water supply pipe 6B is The tip 6B1 is inserted and connected so as to be positioned closer to the center of the heating container 15c. Thereby, the city gas which is a to-be-reformed gas is supplied from the to-be-reformed gas supply pipe 6A, and the water is supplied from the water supply pipe 6B to the same space in the heating container 15c.

  Specifically, both the reformed gas supply pipe 6A and the water supply pipe 6B communicate with the buffer space BS in the heating container 15c in which a large number of granular ceramic balls CB are accommodated. In particular, at least one ceramic ball (CB1, CB2, etc.) is arranged in a range S in which water can drip as indicated by arrows W1, W2 from the tip 6B1 of the water supply pipe 6B to the bottom surface 15c2 of the heating container 15c. Yes. As described above, the tip 6B1 of the water supply pipe 6B is located closer to the center of the heating vessel 15c than the tip 6A1 of the reformed gas supply pipe 6A. One ceramic ball (CB3, CB4, etc.) is arranged. In the present embodiment, the ceramic ball CB has a spherical shape, but the present invention is not limited to this and can take various shapes.

  Here, in the present embodiment, the inside of the heating container 15c is not partitioned, and only one space is formed. However, the heating container 15c is divided by providing appropriate partitions on the upstream side / downstream side, or above / below. It doesn't matter. However, even in that case, the reformed gas supply pipe 6A and the water supply pipe 6B need to be connected so as to communicate with the same space in which the ceramic balls CB are disposed.

  The tip end 6A1 of the reformed gas supply pipe 6A is covered with the mesh member 20 from the buffer space BS. As shown in detail in FIG. 8, the mesh member 20 includes an annular frame 20a, a mesh 20b formed by intersecting wires in the frame 20a, and a ventilation hole 20c formed between the wires. It is made of a metal having high heat resistance such as stainless steel. By covering the tip portion 6A1 of the reformed gas supply pipe 6A with this net-like member, it is possible to supply the city gas to the buffer space BS through the vent hole 20c, but the ceramic balls CB of the buffer space BS are covered. Clogging due to entering the reformed gas supply pipe 6A can be prevented.

  2 and 3, since the evaporator 15c is disposed in the exhaust gas chamber 17, the evaporator 15c is exposed to exhaust gas discharged from the combustion unit 18 described later and becomes high temperature. Therefore, the water supplied to the buffer space BS in the heating container 15c by the water supply pipe 6B is also heated and evaporated to become water vapor. This steam is mixed with the city gas supplied from the reformed gas supply pipe 6A to the buffer space BS, and this mixed gas is heated in the heating container 15c and then connected to the upper surface of the heating container 15c. To the reformer 5. At this time, the water vapor and the city gas are agitated and further mixed by flowing through the gap between the ceramic balls CB, and receive heat from the surface of the ceramic balls having high thermal conductivity and are efficiently heated. By mixing water vapor with city gas, corrosion in the pipe 6C can be reduced.

  Although not explicitly shown in each drawing, in this embodiment, electromagnetic valves are attached to the reformed gas supply pipe 6A and the water supply pipe 6B, respectively, and each electromagnetic valve is output from a CPU as a control unit. The ratio of gas to be reformed, air and water vapor supplied to the reformer 5 can be changed.

  The city gas as the gas to be reformed introduced into the reformer 5 is reformed by the reforming catalyst stored in the reformer 5. The reformed fuel gas is supplied to the gas tank 3 through the pipe 6D. The portion where the pipe 6C is connected to the reformer 5 and the portion where the pipe 6D is connected to the reformer 5 are separated from each other in the vicinity of one end and the other end in the longitudinal direction. As a result, the fuel gas and air supplied to the reformer 5 can sufficiently touch the reforming catalyst.

  A reforming catalyst is enclosed in the reformer 5. As the reforming catalyst, a catalyst in which nickel is applied to the surface of the alumina sphere and a catalyst in which ruthenium is applied to the surface of the alumina sphere are appropriately used. These reforming catalysts are spheres.

  In the present embodiment, the flow path member 7 is provided so as to cover the reformer 5 and each fuel cell stack 90. The flow path member 7 has air flow path outer walls 71 and 72, an air distribution chamber 73, air collecting chambers 74 and 75, air flow path pipes 76a, 76b, 77a and 77b, and outer walls 78 and 79. Yes. The flow path member 7 is formed such that the air flow path outer walls 71 and 72 are arranged in the longitudinal direction and the outer walls 78 and 79 are arranged in the short direction, respectively, and are formed into a box shape by these members. The flow path member 7 is erected on the partition plate 15 so as to cover the reformer 5 and each fuel cell stack 90. In the following description, the side that contacts the partition plate 15 of the flow path member 7 is defined as the lower side, and the side opposite to the lower side is described as the upper side.

  The air distribution chamber 73 is attached to the upper outside of the outer wall 79. That is, the air distribution chamber 73 is attached to the outside of the box-shaped body formed by the air flow path outer walls 71 and 72 and the outer walls 78 and 79 and above the short side. An air supply pipe 7A is connected to the air distribution chamber 73, and air as an oxidant gas is supplied. Air flow passages 76a, 76b, 77a, 77b are also connected to the air distribution chamber 73.

  The air flow path pipes 76a and 76b are arranged along the air flow path outer wall 71 on the inner side of the box-shaped body formed by the air flow path outer walls 71 and 72 and the outer walls 78 and 79 and above the longitudinal side. Yes. The air channel tube 76a is disposed on the air channel outer wall 71 side, and the air channel tube 76b is disposed on the inner side of the air channel tube 76a. One end of each of the air flow path pipes 76 a and 76 b passes through the outer wall 79 and is connected to the air distribution chamber 73, and the other end is connected to the air collecting chamber 74. Therefore, the air that has flowed into the air distribution chamber 73 flows through the air flow path pipes 76a and 76b into the air collecting chamber 74 and rejoins.

  The air flow path pipes 77a and 77b are arranged along the air flow path outer wall 72 on the inner side and the upper side of the box-shaped body formed by the air flow path outer walls 71 and 72 and the outer walls 78 and 79. Yes. The air flow path pipe 77a is disposed on the air flow path outer wall 72 side, and the air flow path pipe 77b is disposed on the inner side of the air flow path pipe 77a. One end of each of the air passage pipes 77 a and 77 b passes through the outer wall 79 and is connected to the air distribution chamber 73, and the other end is connected to the air collecting chamber 75. Accordingly, the air flowing into the air distribution chamber 73 flows through the air flow path pipes 77a and 77b into the air collecting chamber 75 and rejoins.

  The air collecting chambers 74 and 75 are attached to the upper inside of the outer wall 78. That is, the air collecting chambers 74 and 75 are attached to the inside of the box-like body formed by the air flow path outer walls 71 and 72 and the outer walls 78 and 79 and above the short side. The air collecting chamber 74 is disposed so as to be in close contact with the air flow path outer wall 71, and the air that has flowed into the air collecting room 74 is configured to flow out to the air flow path outer wall 71. On the other hand, the air collecting chamber 75 is disposed so as to be in close contact with the air flow path outer wall 72, and the air flowing into the air collecting chamber 75 is configured to flow out to the air flow path outer wall 72.

  Each of the air flow path outer walls 71 and 72 has a double wall structure, and is configured so that air can flow through each of them. More specifically, the air flow path outer wall 71 has a structure divided into three chambers from above, and is formed as a first chamber 91, a second chamber 92, and a third chamber 93 in this order from above. The air that flows from the air collecting chamber 74 flows into the first chamber 91, then flows into the second chamber 92, and then flows into the third chamber 93. Similarly, the air flow path outer wall 72 is also divided into three chambers from above, and is formed as a first chamber 94, a second chamber 95, and a third chamber 96 in order from the top. The air flowing from the air collecting chamber 75 flows into the first chamber 94, then flows into the second chamber 95, and then flows into the third chamber 96.

  In the third chambers 93 and 96, a plurality of air inflow holes 93a and 96a are formed at predetermined intervals, respectively. The air inflow holes 93a and 96a are located in the direction in which the fuel cell stack 90 is connected to the gap between the fuel cells 4 and the vertical positions relative to the fuel cells 4 are substantially the same. A plurality of them are formed.

  The air flowing into the air flow path outer walls 71 and 72 is configured to flow into the vicinity of the fuel cell 4 in the power generation chamber 16 through the air inflow holes 93a and 96a. The air (power generation air) that flows through the air inflow holes 93 a and 96 a flows from the lower side to the upper side of each fuel cell 4 through the outside of the fuel cell 4. Air (power generation air) reaching above each fuel cell 4 is combusted together with the fuel gas that has passed through the pipe flow path of each fuel cell 4.

  Above each fuel cell stack 90 is a combustion section 18 in which air (power generation air) and fuel gas are mixed and burned. The fuel gas rises from the gas tank 3 through the in-pipe flow path 30 c of the fuel cell unit 30 toward the combustion unit 18. Further, the air flowing outside the fuel cell 4 also rises toward the combustion unit 18. An ignition device insertion hole 97 is provided in a portion of the air flow path outer wall 72 corresponding to the combustion portion 18, and an ignition device (not shown) for starting combustion of combustion gas and air burns from the ignition device insertion hole 97. Projected to the portion 18. The ignition device mixes and burns fuel gas and air. The fuel cells 4 constituting the fuel cell stack 90 are heated from above by the combustion unit 18. In addition, the air flowing through the air inflow holes 93a and 96a is also heated by the combustion in the combustion section 18 while passing through the air passage pipes 76a, 76b, 77a and 77b and the air passage outer walls 71 and 72 as described above. Is done.

  In the fuel cell module 102 according to the present embodiment, the to-be-reformed gas supply pipe 6A and the water supply pipe 6B are in the same space in the heating container 15c and communicate with a buffer space BS in which a large number of ceramic balls CB are accommodated. Since it is connected, even if the water vapor partial pressure suddenly rises due to bumping of water supplied to the buffer space BS in the heating container 15c of the evaporator 19 from the water supply pipe 6B, it is accommodated there. The ceramic ball CB is used as a buffer material, and the influence on the reformed gas supply pipe 6A is mitigated. Accordingly, a situation in which the supply of the city gas from the reformed gas supply pipe 6A to the heating container 15c is hindered by the increase in the partial pressure of the water vapor in the heating container 15c is prevented, and the city gas is stably evaporated. Can be supplied to.

  In addition, at least one ceramic ball (CB1, CB2, etc.) is disposed in a range S where water drops from the water supply pipe 6B on the bottom surface 15c2 of the heating container 15c. If the water dripped from the water supply pipe 6B to the bottom surface 15c2 of the heating container 15c of the evaporator 19 becomes spherical, the surface area is small with respect to its volume, which may cause bumping or take time to evaporate. A situation occurs in which mixing cannot be performed smoothly. According to the present embodiment, the water dripped from the water supply pipe 6B comes into contact with the ceramic balls (CB1, CB2, etc.) arranged in the range S and spreads along the surface, thereby increasing the surface area and evaporating. Therefore, bumping is suppressed and the city gas can be supplied to the evaporator more stably, and the water vapor and the reformed gas can be mixed well.

  The tip 6B1 of the water supply pipe 6B is disposed closer to the center of the heating vessel 15c than the tip 6A1 of the reformed gas supply pipe 6A, and at least one ceramic ball is between the two tips. (CB3, CB4, etc.) is arranged, even if the water supplied from the tip 6B1 of the water supply pipe 6B evaporates in the buffer space BS and the water vapor partial pressure rapidly increases, With ceramic balls (CB3, CB4, etc.) arranged between the front ends, the influence is reliably mitigated, and city gas can be stably supplied from the reformed gas supply pipe 6B into the buffer space BS. it can. Note that the reformed gas supply pipe 6 </ b> A may be selected on the contrary to the above as a pipe for positioning the tip part from the center part of the heating container 15 c.

4 Fuel Cell 5 Reformer 6A Reformed Gas Supply Pipe 6A1 Tip of Reformed Gas Supply Pipe 6B Water Supply Pipe 6B1 Tip of Water Supply Pipe 15c Heating Container 16 Power Generation Chamber 17 Exhaust Gas Chamber 19 Evaporator 20 Reticulated member 30 Fuel cell unit 90 Fuel cell stack (fuel cell)
102 Fuel cell module BS Buffer space CB Ceramic ball (granular body)

Claims (4)

A fuel cell stack in which a plurality of fuel cells that generate power using fuel gas and oxidant gas are arranged; and a combustion section that burns the fuel gas and the oxidant gas above the fuel cell stack. A fuel cell module comprising:
The fuel cell module has a heating container that generates steam by evaporating water inside, which is necessary for reforming the gas to be reformed into the fuel gas by a steam reforming reaction,
The heating container extends in the longitudinal direction of the fuel cell stack in which the plurality of fuel cells are arranged, and is exposed to exhaust gas discharged from the combustion unit,
Inside the heating container, a reformed gas supply pipe for supplying the reformed gas, a water supply pipe for supplying the water, and a mixed gas of the generated water vapor and the fuel gas are discharged. An outlet, and
The to-be-reformed gas supply pipe and the water supply pipe communicate with a buffer space that relieves an increase in the partial pressure of water vapor inside the heating container by a large number of granular materials housed in the heating container. Connected on the same side in the heating vessel,
The fuel cell module according to claim 1, wherein the reformed gas supply pipe and the water supply pipe are separated near one end and near the other end in the longitudinal direction of the discharge port and the heating container.   2. The fuel cell module according to claim 1, wherein at least one granular body is disposed in a range where water drops from the water supply pipe at a bottom surface of the heating container.   2. The fuel cell module according to claim 1, wherein at least one tip of the water supply pipe and the reformed gas supply pipe is covered with a mesh member. One end portion of the water supply pipe and the to-be-reformed gas supply pipe is disposed so as to be closer to the center portion of the heating container than the other end portion, and at least one between the both end portions. The fuel cell module according to claim 1, wherein two granular bodies are arranged.

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