JP4859359B2 - Operation method of fuel cell - Google Patents

Description

The present invention relates OPERATION method for a fuel cell formed by accommodating a plurality of fuel cells in a housing.

  Conventionally, since the operating temperature of a fuel cell using a solid electrolyte is as high as 600 to 1000 ° C., it is necessary to heat the fuel cell up to this temperature, and there is a problem that it takes a long time to generate power. In order to solve such problems, conventionally, a preheater for preheating oxygen-containing gas (air) is provided outside the storage container, and the oxygen-containing gas is heated by the preheater and then supplied to the cell stack. It has been proposed to heat the cell and shorten the startup time.

  In addition, the fuel gas and oxygen-containing gas that were not used for power generation are combusted, this high-temperature combustion gas is routed to the outside of the storage container by piping, and heat is supplied along the piping for supplying the oxygen-containing gas to the inside of the storage container. It has been proposed to pre-heat the oxygen-containing gas by exchanging and effectively using the combustion gas.

  Further, in recent years, a burner for heating an oxygen-containing gas is provided in a storage container, the oxygen-containing gas is heated by the burner, and the preheated oxygen-containing gas is supplied to the cell stack (for example, , See Patent Document 1).

Furthermore, in recent years, in order to shorten the start-up time, one provided with a start-up burner for heating the fuel cell is known (see, for example, Patent Documents 2 to 4).
JP 2000-149976 2004-119316 No. 2003-282129 No. 2003-249250

  However, in the fuel cells described in Patent Documents 1 to 4, although the fuel cell can be heated to start up quickly, the load cannot be quickly changed with respect to the external load (power demand). There was a problem. In addition, when starting up, there is a problem that a starting burner for supplying and burning fuel gas separately is required.

That is, for example, when a fuel cell is used at home, as shown in FIG. 6, there are a breakfast time zone and a dinner time zone where electricity is used very much, while at night and daytime when electricity is hardly used. Although there is a time zone, a power generation system that generates a certain amount of power generation regardless of power demand generates wasteful power generation at night or in the daytime when little power is used. For this reason, there is a problem that the amount of fuel gas to be used increases, the cost is high, and the amount of CO ₂ emission increases.

  On the other hand, in a power generation system that operates by changing the power generation amount following the power demand, when the power demand becomes high during partial load operation, the power generation by the fuel cell is not in time, and it can not cope with the rapid power demand There was a problem.

The present invention, even when the power demand rapidly increases, and an object thereof is to provide a OPERATION method of the fuel cell can respond quickly to sudden power demand.

The fuel cell operating method of the present invention includes a plurality of fuel cells and a heater that generates heat using the power generated in the plurality of fuel cells in a housing, and generates a certain amount of power generation. In a fuel cell operation method for generating power by combining a steady operation that performs power generation and a partial load operation that changes the amount of power generation with respect to the required power of an external load, the temperature in the housing during the partial load operation When the temperature is lower than the current temperature, before the predetermined time before the time when the required power of the external load becomes high, a power amount larger than the required power of the external load at that time is generated and surplus supplying power to the heater, wherein the benzalkonium exothermed the heater.

In such a fuel cell operation method, for example, when the temperature in the housing is low during partial load operation, when the temperature in the housing is raised to the temperature during steady operation, the power demand is further reduced at night. Occasionally, the heater is heated to prepare for high power demand. That is, according to the present invention, the heater is heated using the power generated by the fuel cell in the low power demand time zone at night, for example, a predetermined time before the breakfast time zone, when the power demand increases rapidly, The power generation chamber can be heated to increase the amount of power generated by the fuel cells at an accelerated rate, thereby preparing for sudden power demand during breakfast hours.

  Further, when the temperature in the housing is low and the temperature in the housing is raised to the temperature of the power generation room during steady operation, for example, it is daytime a predetermined time before dinner time, and there is usually little demand for power However, in this time zone, the heater can be heated using the power generated by the fuel cell, and the power generation chamber in the housing can be heated to prepare for a sudden power demand in the dinner time zone.

  Usually, since the power demand is low at night, base load operation is performed. At that time, power larger than the demand power can be generated, and the heater can be heated using this surplus power.

Time to heat the heater can be one high power usage pattern learned the inside constant period, generating heat of the heater for a predetermined time period of the predetermined period. If it has a learning function can adopt a more finely operating process with respect to power demand.

  In addition, the following operation method is also possible. In the state where the temperature in the housing (power generation room temperature) is lower than the power generation room temperature during steady operation, such as when partial load operation continues for a long time, the initial Due to the low temperature of the power generation chamber, there was a phenomenon in which the time during which the power generation efficiency was low continued for a long time even when the output reached the required value. This leads to the problem of high running costs.

  In order to eliminate this, in the present invention, in the state where the power generation chamber temperature is lower than the power generation chamber temperature during steady operation, for example, when partial load operation continues for a long time, a larger power demand is required. In this case, the power generation is performed more than the required power amount, and surplus power obtained by subtracting the required power amount from the power generation amount of the fuel cell is consumed by the above-described heater. The reason why surplus power is consumed by the heater is to first prevent the power from flowing back to the grid power, and secondly to quickly raise the temperature of the power generation chamber with the surplus power. By such an operation method, the temperature of the power generation chamber can be quickly increased and operation with high power generation efficiency can be performed, and the running cost can be reduced.

  Further, the fuel cell operating method of the present invention is characterized in that a distributed power generation is performed using a solid oxide fuel cell. Since solid oxide fuel cells are used, highly efficient power generation can be performed. Further, methane, CO, etc. can be used as fuel, the fuel processing unit can be simplified, and low-cost distributed power generation can be performed. Is possible.

  In the fuel cell operation method of the present invention, the heater generates heat using the power generated by the fuel cell in the low power demand time of the night, for example, a predetermined time before the breakfast time, when the power demand increases rapidly. In addition, the power generation chamber in the housing can be heated to increase the power generation amount of the fuel cell at an accelerated rate, thereby preparing for a sudden power demand during the breakfast hours.

In the fuel cell operation method of the present invention, a fuel cell having a power generation unit (hereinafter also referred to as a fuel cell assembly) includes a housing 2 having a substantially rectangular parallelepiped shape as described with reference to FIGS. ing. The outer surface of the six wall surfaces of the housing 2 is a heat insulating wall (heat insulating member) formed of an appropriate heat insulating material, that is, the upper heat insulating wall 4, the lower heat insulating wall 6, the right heat insulating wall 8, the left heat insulating wall 9, and the front A heat insulating wall 10 and a rear heat insulating wall 11 are provided. A power generation / combustion chamber 12 is defined in the housing 2.

  The front heat insulation wall 10 and / or the rear heat insulation wall 11 is detachably or removably attached, and the front heat insulation wall 10 and / or the rear heat insulation wall 11 is detached or opened to access the power generation / combustion chamber 12. be able to. If desired, an outer wall, which may be made of a metal plate, can be disposed on the outer surface of each heat insulating wall.

  An air chamber (gas chamber) 16 is disposed at the upper end of the housing 2. The air chamber 16 is defined in a rectangular parallelepiped case 17 having a relatively small vertical dimension. The air chamber 16 communicates with the upper end of an air introduction pipe (gas supply means) 22 for sending air (oxygen-containing gas) toward the power generation / combustion chamber. There are a plurality of air introduction pipes 22 and the shape thereof may be a cylinder or a hollow plate structure. 1 and 2, a cylindrical air introduction tube 22 is shown. The air introduction pipe 22 is disposed between the cell stacks described later, and has an opening at the lower end portion of the cell, and air is ejected from the opening portion. The air introduction tube 22 is preferably made of a material having high heat resistance such as ceramics.

  The air chamber 16 is provided with a low-temperature gas supply pipe 18, and the low-temperature gas supply pipe 18 penetrates the upper heat insulating wall 4 and extends to the outside.

  The low-temperature gas supply pipe 18 supplies the same type of gas as that supplied into the air chamber 16, that is, low-temperature air, into the air chamber 16. The air supplied through the low-temperature gas supply pipe 18 is It must be cooler than the temperature of the preheated air. In particular, about room temperature is desirable.

  As shown in FIG. 2, the low temperature gas supply pipe 18 is connected to a position of the air chamber 16 that cools the power generation units 56a, 56b, 56c, and 56d, that is, the central portion of the fuel cell assembly. In other words, the air introduction pipe 22 disposed between the power generation units 56a, 56b, 56c, and 56d has a low temperature so as to open at the position of the opposing case 17 side plate with respect to the center of the opening assembly to the case 17 side plate. A gas supply pipe 18 is provided.

  A heat exchanger 24 having a flat plate shape as a whole is disposed on both sides of the housing 2, more specifically, inside the right heat insulating wall 8 and inside the left heat insulating wall 9. Each of the heat exchangers 24 is constituted by a case 26 having a hollow flat plate shape extending substantially vertically.

  A partition plate 28 located in the middle in the lateral direction is disposed in the case 26, and the inside of the case 26 is partitioned into a discharge path 30 positioned on the inner side and an inflow path 32 positioned on the outer side. Three partition walls 34 and 36 are arranged in the discharge path 30 at intervals in the vertical direction. More specifically, in the discharge passage 30, the front edge is located rearwardly away from the front wall (not shown) of the case 26, but the rear edge is the rear wall (not shown) of the case 26. And a partition wall 36 whose front edge is connected to the front wall of the case 26 but whose rear edge is spaced forward from the rear wall of the case 26. Are alternately arranged, and thus the combustion gas discharge passage 30 is zigzag-shaped. If desired, a form other than the zigzag flow path may be used.

  Similarly, the three partition walls 38 and 40, that is, the front edges thereof are also spaced apart from the front wall (not shown) of the case 26 in the inflow path 32 with a space in the vertical direction. The rear wall is connected to the rear wall (not shown) of the case 26, and the front edge of the partition wall 38 is connected to the front wall of the case 26. The partition walls 40 spaced apart from the front are alternately arranged, and thus the inflow passage 32 is also zigzag-shaped. If desired, a form other than the zigzag flow path may be used.

  A discharge opening 42 is formed at the upper end of the inner wall of the case 26, and the discharge path 30 is communicated with the power generation / combustion chamber 12 through the discharge opening 42. In the illustrated embodiment, heat storage walls (heat shielding members) made of a heat storage material are arranged on the power generation / combustion chamber 12 side of the heat exchanger 24, that is, on the fuel cell side and above and below the fuel cell. Has been. That is, the right heat storage wall 44a, the left heat storage wall 44b, the front heat storage wall 44c, the rear heat storage wall 44d, the lower heat storage wall 44e, and the upper heat storage wall 44f are disposed so as to surround the cell assembly. An opening 45 is formed in the upper part of the right heat storage wall 44 a and the left heat storage wall 44 b so as to be located at substantially the same height as the lower edge of the discharge opening 42, and the discharge opening 42 generates power through the opening 45. -It is connected to the combustion chamber 12.

The heat insulating walls 4, 6, 8, 9, 10, and 11 formed on the outer surface of the six wall surfaces of the housing 2 are formed of an alumina / silica general-purpose heat insulating material so as to surround the cell assembly. The heat storage walls 44 a, 44 b, 44 c, 44 d, 44 e, 44 f are formed from a heat insulating material having a higher alumina purity than the heat insulating materials 4, 6, 8, 9, 10. The heat insulating walls 4, 6, 8, 9, 10, 11 and the heat storage walls 44a, 44b, 44c, 44d, 44e, 44f may be formed of the same material, but the density of the heat storage material is larger than that of the heat insulating material. Is desirable. The heat insulating walls 4, 6, 8, 9, 10, 11 have a density of 0.26 g / cm ³ or less, and the heat storage walls 44a, 44b, 44c, 44d, 44e, 44f have a density of 0.32 g / cm ³ or less. The thermal conductivity of is preferably 0.1 to 0.4 W / (m · K).

  An inflow opening 48 is formed on the outer side of the upper wall of the case 26, and the inflow path 32 is communicated with the air chamber 16 through the inflow opening 48. The heat exchanger 24 and the inflow opening 48 constitute a gas supply channel. A double cylinder 50 (only the upper end portion is shown in FIG. 1) extending in the vertical direction is disposed behind each of the inflow passages 32. The double cylinder 50 is an outer cylinder member. 52 and an inner cylindrical member 54. The lower end of the discharge path 30 is connected to the lower end of the discharge path defined between the outer cylinder member 52 and the inner cylinder member 54, and the lower end of the inflow path 32 is defined in the inner cylinder member 54. Connected to the inflow channel.

  Thus, the configuration of the fuel cell assembly shown in the drawing is substantially the same as the fuel cell assembly disclosed in the specification and drawings of Japanese Patent Application No. 2003-295790 filed by the present applicant. Therefore, the details of the configuration described above are left to the specification and drawings of Japanese Patent Application No. 2003-295790, and the description thereof is omitted in this specification.

  Four power generation units 56a, 56b, 56c and 56d are arranged in the lower part of the above-described power generation / combustion chamber. The power generation units 56a, 56b, 56c, and 56d are respectively positioned between the air introduction pipes 22 described above. In other words, the air introduction pipe 22 is disposed between the power generation units 56a, 56b, 56c and 56d. 3 and 4 together with FIGS. 1 and 2, the power generation unit 56a includes a rectangular parallelepiped fuel gas case 58a extending in the front-rear direction (direction perpendicular to the paper surface in FIG. 1). .

  A cell stack 60a is mounted on the upper surface of the fuel gas case 58a that defines the fuel gas chamber. The cell stack 60a is configured by arranging a plurality of upright cells 62 extending in the vertical direction in the longitudinal direction of the fuel gas case 58a (that is, in the front-rear direction). As clearly shown in FIG. 5, each cell 62 includes an electrode support substrate 64, a fuel electrode layer 66 that is an inner electrode layer, a solid electrolyte layer 68, an oxygen electrode layer 70 that is an outer electrode layer, and an interconnector 72. Has been.

  The electrode support substrate 64 is a columnar plate-like piece that is elongated in the vertical direction, and the cross-sectional shape thereof has both flat surfaces and both sides of a semicircular shape. The electrode support substrate 64 is formed with a plurality (six in the illustrated example) of fuel gas passages 74 penetrating the electrode support substrate 64 in the vertical direction. Each of the electrode support substrates 64 is bonded to the upper wall of the fuel gas case 58a by, for example, a ceramic adhesive having excellent heat resistance.

  On the upper wall of the fuel gas case 58a, a plurality of slits (not shown) extending in the left-right direction are formed at intervals in a direction perpendicular to the paper surface in FIG. A fuel gas passage 74 is communicated with the fuel gas chamber according to each of the slits.

  The interconnector 72 is disposed on one side of the electrode support substrate 64 (upper surface in the cell stack 60a in FIG. 5). The fuel electrode layer 66 is disposed on the other surface (the lower surface in the cell stack 60a of FIG. 5) and both side surfaces of the electrode support substrate 64, and both ends thereof are joined to both ends of the interconnector 72. The solid electrolyte layer 68 is disposed so as to cover the entire fuel electrode layer 66, and both ends thereof are joined to both ends of the interconnector 72. The oxygen electrode layer 70 is disposed on the main part of the solid electrolyte layer 68, that is, on the portion covering the other surface of the electrode support substrate 64, and is positioned to face the interconnector 72 with the electrode support substrate plate 64 interposed therebetween. Yes.

  A current collecting member 76 is disposed between adjacent cells 62 in the cell stack 60a, and connects the interconnector 72 of one cell 62 and the oxygen electrode layer 70 of the other cell 62. Current collecting members 76 are disposed on both ends of the cell stack 60a, that is, on one side and the other side of the cell 62 positioned at the upper end and the lower end in FIG. Electric power extraction means (not shown) is connected to the current collecting members 76 located at both ends of the cell stack 60a, and the electric power extraction means is the front heat insulation wall 10, the rear heat insulation wall 11 or the lower heat insulation wall of the housing 2. The material 6 extends outside the housing 2. If desired, the cell stacks 60a, 60b, 60c and 60d are connected in series with each other by appropriate connection means instead of disposing the power extraction means in each of the cell stacks 60a, 60b, 60c and 60d. Common power extraction means may be provided for the cell stacks 60a, 60b, 60c and 60d.

  More specifically about the cell 62, the electrode support substrate 64 is gas permeable to allow fuel gas to permeate to the anode layer 66, and is also conductive to collect current through the interconnector 72. Can be formed from a porous conductive ceramic (or cermet) that satisfies such requirements.

  In order to manufacture the cell 62 by co-firing with the fuel electrode layer 66 and / or the solid electrolyte layer 68, it is preferable to form the electrode support substrate 64 from the iron group metal component and the specific rare earth oxide. In order to provide the required gas permeability, it is preferred that the open porosity is in the range of 30% or more, in particular 35 to 50%, and the conductivity is also 300 S / cm or more, in particular 440 S / cm or more. Is preferred.

The fuel electrode layer 66 can be formed of a porous conductive ceramic, for example, ZrO ₂ (referred to as stabilized zirconia) in which a rare earth element is dissolved and Ni and / or NiO.

The solid electrolyte layer 68 has a function as an electrolyte for bridging electrons between electrodes, and at the same time needs to have a gas barrier property in order to prevent leakage between fuel gas and air. In general, it is formed from ZrO ₂ in which ₃ to 15 mol% of a rare earth element is dissolved.

The oxygen electrode layer 70 can be formed of a conductive ceramic made of a so-called ABO ₃ type perovskite oxide. The oxygen electrode layer 70 is required to have gas permeability, and the open porosity is preferably 20% or more, particularly preferably in the range of 30 to 50%.

Although the interconnector 72 can be formed from a conductive ceramic, it needs to have a reduction resistance and an oxidation resistance in order to come into contact with a fuel gas and air that may be hydrogen gas. A perovskite oxide (LaCrO ₃ oxide) is preferably used. The interconnector 72 must be dense in order to prevent leakage of fuel gas passing through the fuel gas passage 74 formed in the electrode support substrate 64 and air flowing outside the electrode support substrate 64, and is 93% or more. In particular, it is desired to have a relative density of 95% or more.

  The current collecting member 76 can be composed of a member having an appropriate shape formed of a metal or alloy having elasticity, or a member obtained by adding a required surface treatment to a felt made of metal fiber or alloy fiber.

  Continuing the description with reference to FIG. 4, the power generation unit 56 a also includes a reforming case 78 a that is preferably a rectangular shape (or a cylindrical shape) that extends elongated in the front-rear direction above the cell stack 60 a. ing. One end, that is, the upper end of the fuel gas supply pipe 80a is connected to the front surface of the reforming case 78a.

  The fuel gas supply pipe 80a extends downward, then curves and extends rearward, and the other end of the fuel gas supply pipe 80a is connected to the front surface of the fuel gas case 58a. One end of a reformed gas supply pipe 82a is connected to the rear surface of the reforming case 78a. The to-be-reformed gas supply pipe 82 a extends downward from the reforming case, and extends under the housing 2 and out of the housing 2.

  The to-be-reformed gas supply pipe 82a is connected to a to-be-reformed gas supply source (not shown) which may be a hydrocarbon gas such as city gas, and is connected to the reforming case 78a through the to-be-reformed gas supply pipe 82a. A gas to be reformed is supplied. An appropriate reforming catalyst for reforming the fuel gas into a hydrogen-rich fuel gas is accommodated in the reforming case 78a.

  In the illustrated embodiment, the reforming case 78a is connected to the fuel gas case 58a via the fuel gas supply pipe 80a and is held in a required position by this, but if necessary, the two-dot chain line in FIG. For example, an appropriate support member 84a can be provided between the lower surface of the reformed gas supply pipe 82a and the lower surface or rear surface of the rear end portion of the fuel gas case 58a.

  Referring to FIG. 3, the power generation unit 56c is substantially the same as the power generation unit 56a described above, and the power generation units 56b and 56d are disposed in the front-rear direction opposite to the power generation units 56a and 56c. Fuel gas supply pipes (not shown) connecting the quality cases 78b and 78d and the fuel gas cases 58b and 58d are arranged on the rear side, and the reformed gas supply pipes 82b and 82d are located downward from the reforming case. It extends under the housing 2 and extends out of the housing 2.

  The reformed gas supply pipes 82 a to 82 d are connected to a fuel gas supply device 91 that supplies fuel gas outside the housing 2. The fuel gas supply device 91 supplies the reformed gas to the reformed gas supply pipes 82a to 82d at a predetermined pressure.

  In the fuel cell of the present invention, six heaters 95 made of W, Mo, etc. are arranged at predetermined intervals in the height direction on the right heat storage wall 44a and the left heat storage wall 44b in the housing 2 (FIG. 1). In the direction perpendicular to the paper surface). These heaters 95 are provided on the right heat storage wall 44 a and the left heat storage wall 44 b located on the side of the fuel battery cell 62. Both ends of these heaters 95 are connected to a control device (not shown), and are configured to generate heat using electric power generated in the plurality of fuel cells 62.

The heater 95 is a case generating chamber temperature inside housings is low, when the temperature is raised to the power generation chamber temperature during steady operation, further nighttime less power demand is controlled so as to generate heat.

  In the present invention, the power demand is rapidly increased, for example, a predetermined time before the breakfast time zone, the heater is heated using the power generated by the fuel cell in the low power demand time zone at night, and the power generation in the housing is performed. -The combustion chamber 12 can be heated to increase the amount of power generated by the fuel cells at an accelerated rate, thereby preparing for sudden power demand during breakfast hours.

  In addition, since the power demand is low at night, the base load operation is performed. At that time, power larger than the demand power can be generated, and the surplus power can be used to heat the heater.

Time to heat the heater can be one high power usage pattern learned the inside constant period, generating heat of the heater for a predetermined time period of the predetermined period. If it has a learning function can adopt a more finely operating process with respect to power demand.

  In the fuel cell assembly as described above, the gas to be reformed is supplied to the reforming cases 78a, 78b, 78c and 78d via the gas to be reformed supply pipes 82a, 82b, 82c and 82d, and the reforming case 78a. , 78b, 78c and 78d, the fuel defined in the fuel gas cases 58a, 58b, 58c and 58d through the fuel gas supply pipes 80a, 80b, 80c and 80d after being reformed into hydrogen-rich fuel gas. It is supplied to the gas chamber and then supplied to the cell stacks 60a, 60b, 60c and 60d.

In each of the cell stacks 60a, 60b, 60c and 60d, at the oxygen electrode,
1 / 2O ₂ + 2e ⁻ → O ²⁻ (solid electrolyte)
The electrode reaction of
O ²⁻ (solid electrolyte) + H ₂ → H ₂ O + 2e ⁻
The electrode reaction is generated and power is generated.

  Fuel gas and air that have flown upward from the cell stacks 60a, 60b, 60c and 60d without being used for power generation are ignited by an ignition means (not shown) disposed in the power generation / combustion chamber 12 at the time of startup. It is ignited and burned. As is well known, the power generation / combustion chamber 12 has a high temperature of, for example, about 800 ° C. due to power generation in the cell stacks 60a, 60b, 60c and 60d, and also due to combustion of fuel gas and air. The reforming cases 78a, 78b, 78c and 78d are disposed in the power generation / combustion chamber 12, and are positioned immediately above the cell stacks 60a, 60b, 60c and 60d, and are directly heated by the combustion flame. Thus, the high temperature generated in the power generation / combustion chamber 12 is effectively used for reforming the reformed gas.

  The combustion gas generated in the power generation / combustion chamber 12 flows into the discharge passage 30 from the discharge opening 42 formed in the heat exchanger 24, and flows through the discharge passage 30 extending in a zigzag shape. 50 is discharged through a discharge passage defined between the outer cylinder member 52 and the inner cylinder member 54. When the combustion gas flows through the discharge path in the double cylinder 50, air flows through the inflow path in the double cylinder 50, and heat exchange is performed between the combustion gas and air.

  Further, when the combustion gas is caused to flow in the exhaust passage 30 of the heat exchanger 24 in a zigzag manner, the air is caused to flow so as to face the inflow passage 32 of the heat exchanger 24 in a zigzag manner. Thus, heat is effectively exchanged between the combustion gas and air to preheat the air.

  When part or all of the cell stacks 60a, 60b, 60c and 60d deteriorates due to power generation over a long period of time, the front heat insulation wall 10 or the rear heat insulation wall 11 of the housing 2 is detached or opened. Part or all of the power generation units 56 a, 56 b, 56 c and 56 d are taken out from the housing 2.

  Then, replace some or all of the power generation units 56a, 56b, 56c and 56d with new ones, or only the cell stacks 60a, 60b, 60c and 60d in some or all of the power generation units 56a, 56b, 56c and 56d. May be replaced with a new one and mounted again at a required position in the housing 2. Even when it is necessary to replace the reforming catalyst accommodated in the reforming cases 78a, 78b, 78c and 78d in some or all of the power generation units 56a, 56b, 56c and 56d, the power generation units 56a, 56b , 56c and 56d are removed from the housing 2, and the reforming cases 78a, 78b, 78c and 78d themselves in the power generation units 56a, 56b, 56c and 56d are replaced with new ones or reforming cases. Only the reforming catalyst in 78a, 78b, 78c and 78d may be replaced with a new one.

  In order to be able to perform the replacement of the reforming catalyst in the reforming cases 78a, 78b, 78c and 78d sufficiently easily, a part of the reforming cases 78a, 78b, 78c and 78d can be opened and closed if desired. It can be put on the door.

  On the other hand, air is supplied to the inflow path 32 of the heat exchanger 24 through the inflow path defined in the inner cylinder member 54 of the double cylinder 50, and is preheated (heated) through the heat exchanger 24. Is temporarily stored in the air chamber 16 and supplied between the cell stacks of the combustion / power generation chamber 12 through the air introduction pipe 22. At this time, the air introduction pipe 22 passes through the combustion gas atmosphere that burns in the vicinity of the fuel gas passage 74 at the upper end of the fuel cell 62 of the cell stack 60. Accordingly, the preheated air in the air chamber 16 is further heated in the combustion region above the cell stack 60, and the air heated to a high temperature is supplied to the cell.

  During normal operation, air preheated by the heat exchanger 24 is introduced into the air chamber 16, and air is introduced from the air chamber 16 into the combustion / power generation chamber 12 using the air introduction pipe 22. When the temperature rises more than expected, the low-temperature air that has passed through the low-temperature gas supply pipe 18 that does not pass through the heat exchanger 24 is introduced into the air chamber 16 and preheated through the heat exchanger 24. And the air temperature of the air chamber 16 is reduced to some extent. By supplying this air between the power generation chambers 12, that is, between the cell stacks, air having a lower temperature than that during normal operation is introduced between the cell stacks. Therefore, a good fuel cell assembly that can appropriately control the temperature in the power generation chamber is provided.

  Moreover, since the air temperature in the air chamber 16 is mixed with the outside air supplied from the low temperature gas supply pipe 18 and the air preheated through the heat exchanger 24, the air temperature is not as low as room temperature. Even if the fuel cell 60 is supplied to the hot fuel cell 60, it is possible to avoid problems such as cracking of the fuel cell 60 and thermal shock destruction, so that the deterioration of the function of the entire fuel cell can be suppressed and the life can be extended.

  Furthermore, by supplying the supply of the low temperature gas from the low temperature gas supply pipe 18 toward the center of the opening of the air supply pipe 22, the air heated from the heat exchangers on both sides is further directed to the center of the opening. The air supplied through the air supply pipe 22 to the center of the cell assembly that is most easily heated can be at the lowest temperature, and the temperature can be increased as the distance from the center increases. can do.

  Further, the right heat storage wall 44a, the left heat storage wall 44b, the front heat storage wall 44c and the rear heat storage wall 44d, the lower heat storage wall 44e, and the upper heat storage wall 44f are disposed in the housing 2 around the cell assembly. By arranging the upper heat insulating wall 4, the lower heat insulating wall 6, the right heat insulating wall 8, the left heat insulating wall 9, the front heat insulating wall 10 and the rear heat insulating wall 11, the high temperature heat around the cell is stored by the heat storage wall, The heat dissipation to the outside can be effectively suppressed together with the heat storage wall and the heat insulating material, and in the fuel cell assembly for distributed power generation, the power generation temperature is effectively reduced even during partial load operation with a small amount of heat generation. Can be maintained.

  In other words, the fuel cell assembly for distributed power generation is small because the power generation amount is small, and is self-sustaining in the normal operation and generates power effectively. However, if the power generation amount is reduced by reducing the fuel gas amount, In the present invention, the heat is effectively confined in the housing by the heat insulating wall, the high-temperature heat in the steady operation is absorbed by the heat storage wall, the partial load operation is performed, and the heat generation amount is reduced. When the temperature decreases, heat can be dissipated and the temperature inside the housing can be effectively maintained.

  In the present invention, the reforming case may be a case other than the upper part of the cell stack or a case where the reforming case is not provided in the housing.

  Further, in the above embodiment, a case has been described in which low temperature gas supply means is provided in the air chamber and air is supplied to the outer surface of the fuel cell by the air supply pipe, but air is supplied to the inside of the fuel cell by the air supply pipe. Of course, it may be made to do. In this case, it goes without saying that an air electrode is formed inside the fuel cell and a fuel electrode is formed outside.

(how to drive)
As shown in FIG. 6, in households that perform distributed power generation, the power demand is very high during breakfast and dinner, and extremely low during the night and during the day, with power consumption of 300 W or less. Continues for more than a few hours. When the demand for electric power is very large, a portion larger than the amount of power generation (maximum output) in the fuel cell is covered by electric power from the electric power company.

  And, in the present invention, in a low power demand time zone during the night, a predetermined time before a time zone where the power usage is high (a time zone of maximum output, for example, a breakfast time zone) in a time zone where the power usage is low, The power generated by the fuel cell and surplus power that is not supplied to the outside is used to heat the heater, the power generation chamber in the housing is heated, and the power generation amount of the fuel cell is increased at an accelerated rate. Can be prepared for sudden power demand.

  For example, during breakfast and dinner hours, the heater generates heat using the power generated by the fuel cells 30 minutes ago and surplus power that is not supplied to the outside, heating the power generation chamber in the housing, and high power It is possible to create an environment that can generate electricity and respond quickly to rapid high power during breakfast and dinner hours.

  Although the fuel cell assembly shown in FIGS. 1 to 5 has been described in the above embodiment, it is not particularly limited.

Sectional drawing which shows suitable embodiment of the fuel cell used for the operating method of the fuel cell of this embodiment . The top view of FIG. FIG. 2 is a perspective view showing a power generation unit assembly used in the fuel cell assembly of FIG. 1. The perspective view which shows the electric power generation unit of FIG. Sectional drawing which shows the cell stack of FIG. It is a graph which shows the change of electric power demand.

Explanation of symbols

2: Housing 12: Power generation / combustion chamber 16: Air chamber (gas chamber)
22: Air supply pipe (gas supply pipe)
24: Heat exchangers 56a, 56b, 56c and 56d: Power generation units 58a, 58b, 58c and 58d: Fuel gas cases 60a, 60b, 60c and 60d: Cell stack 62: Fuel cell 78a, 78b, 78c and 78d: Modified Quality case 91: fuel gas supply device

Claims (4)

The housing includes a plurality of fuel cells and a heater that generates heat using the electric power generated by the plurality of fuel cells, for steady operation for generating a certain amount of power generation, and for the required power of the external load. In the method of operating a fuel cell that performs power generation in combination with partial load operation that changes the amount of power generation, when the temperature in the housing during the partial load operation is lower than the temperature during the steady operation, Before a predetermined time before the required power of the external load becomes high, the power generation is larger than the required power of the external load at that time, and surplus generated power is supplied to the heater. the fuel cell operating method characterized by the Turkey is exothermic.   2. The method of operating a fuel cell according to claim 1, wherein the time when the temperature in the housing is lower than the temperature during the steady operation is during nighttime when the power demand of the external load is low.   The high power usage pattern within a predetermined period is learned, and the time when the temperature in the housing is lower than the temperature during the steady operation is set as a predetermined time period within the predetermined period. The operation method of the fuel cell as described.   4. The fuel cell operating method according to claim 1, wherein a solid electrolyte fuel cell is used as the fuel cell, and distributed power generation is performed. 5.

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