JP2017117550A - Fuel cell cartridge, fuel cell module, and control device and control method of fuel cell cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the power generation efficiency by uniformizing a temperature distribution between fuel cell stacks while avoiding an increase in cost, space expansion, and complication of operation and control.SOLUTION: A fuel cell cartridge comprises: a plurality of fuel cell stacks 101; a fuel gas supply header 217 which supplies a fuel gas supplied from the outside of a cartridge to the inside of the fuel cell stacks 101; and a fuel gas exhaust header 101 which exhausts a fuel gas exhausted from the inside of the fuel cell stacks 101 to the outside of the cartridge. The fuel cell cartridge is also equipped with inert gas supply means 10 for supplying an inert gas from the outside of the cartridge to the fuel cell stacks 101 in a specific region which relatively becomes a high temperature among the plurality of fuel cell stacks 101.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a fuel cell cartridge, a fuel cell module including the same, and a control device and a control method for the fuel cell cartridge.

There is known a fuel cell that generates electric power by chemically reacting a fuel gas and an oxidizing gas. Among these, a solid oxide fuel cell (SOFC) uses ceramics such as zirconia ceramics as an electrolyte, such as hydrogen (H ₂ ), carbon monoxide (CO), and methane (CH ₄ ). It is a fuel cell that is operated using as a fuel a gas produced from a carbonaceous raw material such as hydrocarbon gas such as hydrocarbon gas, city gas, natural gas, petroleum, methanol, and coal gasification gas by a gasification facility. Such an SOFC has a high operating temperature of about 700 to 1000 ° C. in order to increase the ionic conductivity, and is known as a high-efficiency high-temperature fuel cell that is versatile (see Patent Documents 1 to 4).

  A combined power generation system in which such an SOFC is combined with an internal combustion engine such as a micro gas turbine (hereinafter referred to as “MGT”) has been developed. In this MGT, the compressed air discharged from the compressor is supplied to the SOFC air electrode, and the high-temperature exhaust fuel gas discharged from the SOFC is supplied to the MGT combustor via the blower for combustion, and combustion is performed. By rotating the MGT turbine with the combustion gas generated in the generator and rotating the generator, it is possible to generate power with high power generation efficiency.

  Development of a triple combined cycle in which such SOFC is combined with GTCC (gas turbine combined cycle) is also underway. GTCC is a combined cycle that combines a gas turbine, an exhaust gas boiler, and a steam turbine that have a system that recovers heat from the high exhaust gas energy of the gas turbine using an exhaust gas boiler and a steam turbine, and is capable of achieving high plant efficiency. Yes. It is possible to achieve higher plant efficiency by combining a SOFC with the GTCC topping side (upstream side of the gas turbine) to form a triple combined cycle.

JP-A-1-320773 JP 2014-164903 A JP 2005-129513 A JP 2014-192123 A

  By the way, SOFC is normally comprised as a fuel cell module provided with the some fuel cell cartridge in the casing containing a heat insulating material. In the fuel cell cartridge, a plurality of fuel cell stacks are assembled in parallel to the supply of fuel gas and oxidizing gas, and an oxidizing gas supply header and a fuel discharge header are provided on one end side thereof, and the other end side is oxidized. A gas exhaust header and a fuel supply header are provided. By allowing the fuel to flow from one end side to the other end inside the fuel cell stack and oxidizing gas from one end to the other end around the fuel cell stack, Generate electricity.

  In SOFC, the temperature of the power generation unit during power generation of each fuel cell stack is generally about 700 to 1000 ° C. from the viewpoint of performance and durability, but the power generation reaction of the fuel cell is an exothermic reaction. Therefore, if an attempt is made to improve the power generation output, the temperature of each part of the cell stack will rise while further increasing the temperature of the power generation part of the fuel cell stack, and as the temperature of the power generation part rises, the fuel cell cartridge The temperature of each component device increases. Therefore, it is necessary to consider that the components of the fuel cell cartridge are not damaged due to the temperature rise. Therefore, in order to improve the power generation output of the fuel cell cartridge, it is necessary to manage the temperature of the power generation unit of the fuel cell stack.

In this regard, Patent Document 3 provides a bypass fuel flow path to supply a gas containing unreformed fuel to the high temperature part of the fuel cell stack assembly, thereby reducing the temperature distribution in the power generation part, A configuration for increasing the efficiency of the power generation system is described.
In Patent Document 4, nickel is disposed on the support of the fuel cell stack, but nickel is not disposed on the upstream support, a small amount of nickel is disposed on the intermediate support, and the downstream support. A structure is described in which more nickel is disposed in the body than in the intermediate region, and a shift reaction is not caused as much as possible upstream of the fuel gas passage, but is caused downstream.

  Conventionally, a fuel cell cartridge is composed of a plurality of fuel cell stacks, and a device for making the temperature uniform in the fuel cell cartridge has been devised. The oxidizing gas and the fuel gas supplied to the fuel cell stack were heated by heat exchange at the ends of the fuel cell stack so that they flow in opposite directions in the longitudinal direction from both ends of the fuel cell stack. Each fuel cell is configured to be consumed later by a power generation reaction in each fuel cell, and the fuel gas and the oxidizing gas are equally distributed to each fuel cell stack in the fuel cell cartridge. The cell stack is designed to generate power evenly, and the temperature distribution of the fuel cell stack is also made uniform.

  However, in each actual fuel cell stack, heat is generated by an electrochemical power generation reaction, and the temperature of the power generation unit (each fuel cell) rises. However, the power generation unit is disposed at both longitudinal ends of the fuel cell stack. There is no heat generation. In addition, since the end of the fuel cell stack tends to dissipate heat to the outside of the cartridge, cooling is promoted. For this reason, the temperature of the fuel cell stack is relatively high due to the heat generated during the power generation reaction of the power generation unit and the fact that it is difficult to dissipate to the surroundings. As a result, the temperature rise is relatively less than that of the fuel cell stack, which is one factor that causes a temperature difference in the longitudinal direction of the fuel cell stack.

  Furthermore, in the fuel cell cartridge, not only does the temperature difference occur in the longitudinal direction of the fuel cell stack, but also there is a temperature difference between the fuel cell stacks (cell stack parallel plane perpendicular to the cell stack longitudinal direction). Occur. In particular, since the fuel cell cartridge dissipates heat to the surroundings, the fuel cell stack near the center of the fuel cell cartridge in the parallel direction of the fuel cell stack is the fuel cell near the periphery of the fuel cell cartridge. The temperature becomes relatively high with respect to the cell stack, and the temperature distribution between the fuel cell stacks becomes uneven. Normally, the fuel gas and the oxidizing gas are set to be equally distributed to each fuel cell stack in the fuel cell cartridge so that each fuel cell stack generates power evenly. The fuel cell stack near the center in the parallel surface direction of the fuel cell stack has less heat radiation than the fuel cell stacks in the parallel surface direction in the fuel cell cartridge. This is one factor that causes a temperature difference in

  On the other hand, in the electrochemical power generation reaction of the fuel cell, the region where the temperature is high is lower than the region where the temperature is low. On the contrary, in the low temperature region, the electrical resistance increases, the electrochemical reaction decreases, the power generation amount decreases, and the temperature rise due to heat generation decreases. In other words, in a situation where the temperature distribution of each fuel cell stack of the fuel cell cartridge is not uniform, by increasing the power generation output, the temperature rise of the fuel cell cartridge is not uniform, and the high temperature region becomes increasingly hot. The temperature distribution may increase. Therefore, the temperature distribution in the longitudinal direction of each fuel cell stack increases, and the temperature distribution in the horizontal plane direction of the fuel cell cartridge also increases, so it is necessary to consider when increasing the power generation output.

  The temperature of the fuel cell stack is such that the temperature near the center is high and the temperature near the surroundings is relatively low in the longitudinal direction and the parallel surface direction. The higher the temperature, the better the power generation efficiency of the fuel cell stack, but the fuel cell stack must be managed so as not to exceed the upper limit temperature set for heat resistance and other conditions. As described above, if the fuel cell stack near the center of the cartridge reaches the maximum temperature and control is performed so as not to exceed the upper limit of the maximum temperature, the temperature of the fuel cell stack near the center (the periphery of the fuel cell cartridge) Lowering power generation efficiency. The performance of the fuel cell cartridge can be improved by making the temperature distribution more uniform (making the fuel cell stack in the fuel cell cartridge as a whole approach the maximum temperature). As a means for making the temperature distribution more uniform, it may be possible to provide a temperature control device such as a heater, but this leads to cost increase, space expansion, and complicated operation and control.

  The present invention was devised in view of such problems, so that the temperature distribution between the fuel cell stacks can be made more uniform while not increasing costs, expanding space, and complicating operation and control. An object of the present invention is to provide a fuel cell cartridge, a fuel cell module including the same, and a control device and a control method for the fuel cell cartridge that can increase the power generation efficiency.

  (1) In order to achieve the above object, a fuel cell cartridge according to the present invention includes a plurality of fuel cell stacks and a fuel gas that is disposed on one end side of the plurality of fuel cell stacks and is supplied from the outside of the cartridge. A fuel gas supply header for supplying the inside of the fuel cell stack and the other end of the plurality of fuel cell stacks, and discharging the fuel gas discharged from the inside of the fuel cell stack to the outside of the cartridge An inert gas supply means for supplying an inert gas from the outside of the cartridge to a fuel cell stack in a specific region that is relatively high in temperature among the plurality of fuel cell stacks. It is characterized by being equipped with.

  (2) Preferably, the specific region is a central region in a plane direction perpendicular to the axial direction of the fuel cell cartridge and includes at least a portion of the central region in the axial direction of the fuel cell cartridge.

  (3) The inert gas supply means is opened at a position corresponding to supply the inert gas to a fuel cell stack in which at least a part is installed in the specific region in the fuel gas supply header. It is preferable to have an inert gas supply hole.

(4) It is preferable that the inert gas supply means has an inert gas supply branch pipe inserted into a fuel gas flow path provided in the fuel cell stack at least a part of which is installed in the specific region. .
(5) It is preferable that the tip opening of the inert gas supply branch pipe is disposed in an intermediate region in the flow direction in the fuel gas flow channel of the fuel cell stack in the specific region.
(6) The inert gas preferably contains nitrogen gas or water vapor.

  (7) The fuel cell module of the present invention is characterized in that a plurality of fuel cell cartridges according to any one of (1) to (6) are provided in a module container.

  (8) The control device for a fuel cell stack according to the present invention is a control device for controlling the plurality of fuel cell stacks in the fuel cell cartridge according to any one of (1) to (6), Fuel gas amount adjusting means for adjusting the amount of fuel gas supplied to the fuel gas supply header; and inert gas amount adjusting means for adjusting the amount of inert gas provided in the inert gas supplying means. A temperature acquisition means for acquiring the temperature of the specific area, a generated power acquisition means for acquiring power generated by the fuel cell cartridge, a temperature of the specific area acquired by the temperature acquisition means, and the generated power acquisition means. Based on the generated power acquired by the above, the fuel is maximized while maintaining the temperature of the specific region within a preset temperature range set in advance. It is characterized by having the scan amount adjusting means and a control means for the controlling the amount of inert gas adjusting means.

  (9) A method for controlling a fuel cell stack according to the present invention is a method for controlling the plurality of fuel cell stacks in the fuel cell cartridge according to any one of (1) to (6), A fuel gas amount adjusting means for adjusting a fuel gas supply amount to the fuel gas supply header; an inert gas amount adjusting means for adjusting an inert gas supply amount by the inert gas supply means; and A temperature acquisition step of acquiring a temperature, a generated power acquisition step of acquiring power generated by the fuel cell cartridge, a temperature of the specific region acquired by the temperature acquisition step, and the generated power acquisition step Based on the generated power, the fuel gas amount adjusting means keeps the temperature of the specific region in a preset temperature range set in advance and maximizes the generated power. It is characterized by and a control step of controlling said inert gas amount adjusting means.

According to the present invention, the inert gas supply means for supplying the inert gas from the outside of the cartridge to the fuel gas supply side of the fuel cell stack in the specific region where the temperature is relatively high among the plurality of fuel cell stacks. Since the fuel cell stack in a specific region is equipped, the amount of fuel gas supplied is reduced by the amount of inert gas supplied, the generated power is reduced and the amount of heat generated by power generation is reduced. descend.
When power is generated by a plurality of fuel cell stacks, the amount of fuel gas supplied is limited so that the temperature of any fuel cell stack is within the upper limit temperature. Although it is limited by the temperature of the fuel cell stack that becomes high temperature, the temperature is lowered by supplying inert gas to the fuel cell stack that becomes relatively high temperature, and the temperature distribution between the fuel cell stacks is Since the fuel gas supplied to a plurality of fuel cell stacks is increased, the number of fuel cell stacks can be made uniform at a temperature close to the upper limit temperature. The generated power can be increased and the power generation efficiency can be increased.

It is a disassembled perspective view which shows the fuel cell module which concerns on 1st, 2 embodiment. It is sectional drawing which shows the fuel cell cartridge which concerns on 1st Embodiment. It is sectional drawing which shows the fuel cell stack concerning 1st, 2 embodiment. It is a conceptual block diagram of the control apparatus of the fuel cell stack concerning 1st, 2 embodiment. It is a figure explaining the effect by control of the fuel cell stack concerning the 1st and 2 embodiments, (a) shows the temperature characteristic of a comparative example, (b) shows the temperature characteristic concerning the 1st and 2 embodiments. Each is shown. It is sectional drawing which shows the fuel cell cartridge which concerns on 2nd Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Here, two embodiments of the first embodiment and the second embodiment will be described. First, referring to FIGS. 1 to 5, a fuel cell module, a fuel cell cartridge, and a fuel cell that are common to the embodiments. The stack will be described. Thereafter, the fuel cell cartridge according to the first embodiment will be described with reference to FIG. 2, and further, control of the fuel cell stack according to the first embodiment will be described with reference to FIGS. 4 and 5. Thereafter, the fuel cell cartridge according to the second embodiment will be described with reference to FIG. In the description of the configuration common to the first embodiment and the second embodiment, each embodiment is simply referred to as an embodiment without distinguishing each embodiment.
Further, in the following, for a solid oxide fuel cell (SOFC), the fuel cell is also referred to as an SOFC cell, the fuel cell stack as a cell stack, the fuel cell cartridge as an SOFC cartridge, and the fuel cell module as an SOFC module. .

[1. SOFC module, SOFC cartridge, cell stack of each embodiment]
In the following, for convenience of explanation, the positional relationship of each component is specified using the expressions “upper” and “lower” on the basis of the paper surface, but this is not necessarily limited to the vertical direction. For example, the upward direction on the paper surface may correspond to the downward direction in the vertical direction. Moreover, you may respond | correspond to the horizontal direction where the up-down direction in a paper surface goes orthogonally to a perpendicular direction.
In the following, a cylindrical shape is described as an example of the cell stack, but it is not necessarily limited to this, and for example, a flat cell stack may be used.

(Cylindrical cell stack structure)
First, the cylindrical cell stack according to each embodiment will be described with reference to FIG. Here, FIG. 3 shows one mode of the cell stack according to each embodiment. The cell stack 101 includes a cylindrical base tube 103, a plurality of SOFC cells 105 formed on the outer peripheral surface of the base tube 103, and an interconnector 107 formed between adjacent SOFC cells 105. The SOFC cell 105 is formed by stacking a fuel electrode 109, a solid electrolyte 111, and an air electrode 113. The cell stack 101 is connected to the air electrode 113 of the SOFC cell 105 formed at the end in the axial direction of the base tube 103 among the plurality of SOFC cells 105 formed on the outer peripheral surface of the base tube 103. The lead film 115 is electrically connected through the via.

(Explanation of materials and functions of each component of cell stack)
The base tube 103 is made of a porous material, for example, CaO stabilized ZrO ₂ (CSZ), Y ₂ O ₃ stabilized ZrO ₂ (YSZ), or MgAl ₂ O ₄ . The base tube 103 supports the SOFC cell 105, the interconnector 107, and the lead film 115, and also supplies fuel gas supplied to the inner peripheral surface of the base tube 103 through the pores of the base tube 103. It diffuses in the fuel electrode 109 formed on the outer peripheral surface.

The fuel electrode 109 is made of an oxide of a composite material of Ni and a zirconia-based electrolyte material. For example, Ni / YSZ is used. In this case, in the fuel electrode 109, Ni that is a component of the fuel electrode 109 has a catalytic action on the fuel gas. This catalytic action reacts with a fuel gas supplied through the base tube 103, for example, a mixed gas of methane (CH ₄ ) and water vapor, and reforms it into hydrogen (H ₂ ) and carbon monoxide (CO). Is. Further, the fuel electrode 109 has an interface between the solid electrolyte 111 and hydrogen (H ₂ ) and carbon monoxide (CO) obtained by reforming and oxygen ions (O ²⁻ ) supplied via the solid electrolyte 111. It reacts electrochemically in the vicinity to produce water (H ₂ O) and carbon dioxide (CO ₂ ). At this time, the SOFC cell 105 generates electric power by electrons emitted from oxygen ions.

The solid electrolyte 111 is mainly made of YSZ having gas tightness that prevents gas from passing through and high oxygen ion conductivity at high temperatures. This solid electrolyte 111 moves oxygen ions (O ²⁻ ) generated at the air electrode to the fuel electrode 109.
The air electrode 113 is made of, for example, a LaSrMnO ₃ oxide or a LaCoO ₃ oxide. The air electrode 113 generates oxygen ions (O ²⁻ ) by dissociating oxygen in an oxidizing gas such as air supplied near the interface with the solid electrolyte 111.

The interconnector 107 is composed of a conductive perovskite oxide represented by M _1-x L _x TiO ₃ (M is an alkaline earth metal element, L is a lanthanoid element) such as SrTiO ₃ system, and is composed of fuel gas and oxidation It is a dense film so that it does not mix with sex gases. Further, the interconnector 107 has stable electrical conductivity in both an oxidizing atmosphere and a reducing atmosphere. The interconnector 107 electrically connects the air electrode 113 of one SOFC cell 105 and the fuel electrode 111 of the other SOFC cell 105 in adjacent SOFC cells 105, and connects adjacent SOFC cells 105 in series. To do.

  Since the lead film 115 needs to have electronic conductivity and a thermal expansion coefficient close to that of other materials constituting the cell stack 101, the lead film 115 is made of Ni such as Ni / YSZ and a zirconia-based electrolyte material. Composed of composite material. The lead film 115 leads the direct-current power generated by the plurality of SOFC cells 105 connected in series by the interconnector to the vicinity of the end of the cell stack 101.

(Description of SOFC module structure and function of each element)
Next, the SOFC module and the SOFC cartridge according to each embodiment will be described with reference to FIG. 1 and FIG.
As illustrated in FIG. 1, the SOFC module 201 includes, for example, a plurality of SOFC cartridges 203 and a pressure container (module container) 205 that stores the plurality of SOFC cartridges 203. The SOFC module 201 includes a fuel gas supply main pipe 207 and a plurality of fuel gas supply branch pipes 207a. A combination of the fuel gas supply main pipe 207 and the plurality of fuel gas supply branch pipes 207a is defined as a fuel gas supply pipe. The SOFC module 201 includes a fuel gas discharge main pipe 209 and a plurality of fuel gas discharge branch pipes 209a. A combination of the fuel gas discharge main pipe 209 and the plurality of fuel gas discharge branch pipes 209a is defined as a fuel gas discharge pipe. The SOFC module 201 has an oxidizing gas supply main pipe (not shown) and an oxidizing gas supply branch pipe (not shown). A combination of the oxidizing gas supply main pipe and the oxidizing gas supply branch pipe is referred to as an oxidizing gas supply pipe. The SOFC module 201 includes an oxidizing gas discharge main pipe (not shown) and a plurality of oxidizing gas discharge branch pipes (not shown). A combination of the oxidizing gas discharge main pipe and the oxidizing gas discharge branch pipe is referred to as an oxidizing gas discharge pipe.

  The fuel gas supply main pipe 207 is provided outside the pressure vessel 205 and is connected to a fuel gas supply unit that supplies a predetermined gas composition and a predetermined flow rate of fuel gas corresponding to the power generation amount of the SOFC module 201 as indicated by an arrow G. In addition, it is connected to a plurality of fuel gas supply branch pipes 207a. The fuel gas supply main pipe 207 branches and guides a predetermined amount of fuel gas supplied from the fuel gas supply section described above to a plurality of fuel gas supply branch pipes 207a. The fuel gas supply branch pipe 207 a is connected to the fuel gas supply main pipe 207 and is connected to a plurality of SOFC cartridges 203. The fuel gas supply branch pipe 207a guides the fuel gas supplied from the fuel gas supply main pipe 207 to the plurality of SOFC cartridges 203 at a substantially equal flow rate, and makes the power generation performance of the plurality of SOFC cartridges 203 substantially uniform. .

  The fuel gas discharge branch pipe 209a is connected to the plurality of SOFC cartridges 203 and to the fuel gas discharge main pipe 209. The fuel gas supply branch pipe 209 a guides the exhaust fuel gas discharged from the SOFC cartridge 203 to the fuel gas discharge main pipe 209. The fuel gas discharge main pipe 209 is connected to a plurality of fuel gas supply branch pipes 209 a and a part thereof is disposed outside the pressure vessel 205. The fuel gas discharge main pipe 209 guides the exhaust fuel gas derived from the fuel gas discharge branch pipe 209a at a substantially equal flow rate to the outside of the pressure vessel 205.

  The pressure vessel 205 is made of a structure and material having a proof strength of an internal pressure of 0.1 MPa to about 1 MPa, and the temperature of the pressure vessel 205 is increased by appropriately providing a heat insulating material between the pressure vessel 205 and the SOFC cartridge 203. By suppressing this, a general structural member (for example, SS400) can be used. In addition, the pressure vessel 205 is made of a structure and material having a proof strength due to the downsizing of the pressure vessel 205, and the temperature of the pressure vessel 205 is prevented from rising by appropriately providing a heat insulating material between the SOFC cartridge 203 and the like. Thus, a general structural member (for example, SS400) can be used. In addition, when the internal temperature rises to about 400 ° C. to about 550 ° C. due to downsizing of the pressure vessel 205 or the like, the material possesses proof strength and corrosion resistance against an oxidizing agent such as oxygen contained in the oxidizing gas. For example, a stainless steel material such as SUS304 is suitable.

  Here, in each of the embodiments, a mode has been described in which a plurality of SOFC cartridges 203 are assembled and stored in the pressure vessel 205. However, the present invention is not limited to this. It can also be set as the aspect accommodated in the container 205. FIG.

  As shown in FIG. 2, the SOFC cartridge 203 includes a plurality of cell stacks 101, a power generation chamber 215, a fuel gas supply header (fuel gas supply chamber) 217, a fuel gas discharge header (fuel gas discharge chamber) 219, an oxidation chamber It has an oxidizing gas supply header (oxidizing gas supply chamber) 221 and an oxidizing gas discharge header (oxidizing gas discharge chamber) 223. A plurality of cell stacks 101 are assembled and installed in parallel. The SOFC cartridge 203 includes an upper tube plate 225a, a lower tube plate 225b, an upper heat insulator 227a, and a lower heat insulator 227b. In each embodiment, the SOFC cartridge 203 includes a fuel gas supply header 217, a fuel gas discharge header 219, an oxidizing gas supply header 221 and an oxidizing gas discharge header 223 as shown in FIG. In this structure, the fuel gas and the oxidizing gas flow so as to face the inside and the outside of the cell stack 101. However, this is not always necessary. For example, the inside and the outside of the cell stack flow in parallel. Alternatively, the oxidizing gas may flow in a direction perpendicular to the longitudinal direction of the cell stack.

  The power generation chamber 215 is an area formed between the upper heat insulator 227a and the lower heat insulator 227b. The power generation chamber 215 is an area in which the SOFC cell 105 of the cell stack 101 is disposed, and electricity is generated by electrochemically reacting a fuel gas and an oxidizing gas. In addition, the middle part of the cell stack 101 in the longitudinal direction of the power generation chamber 215 serves as a power generation unit that generates power, and the temperature near the center in the longitudinal direction of the cell stack 101 is constant due to the heat generated by the power generation. During operation, a high temperature atmosphere of about 700 to 1000 ° C. is obtained.

  The fuel gas supply header 217 is an area surrounded by the upper casing 229a and the upper tube plate 225a of the SOFC cartridge 203. The fuel gas supply header 217 communicates with the fuel gas supply branch pipe 207a through a fuel gas supply hole 231a provided in the upper casing 229a. Further, one end of the cell stack 101 is arranged in the fuel gas supply header 217 such that the inside of the base tube 105 of the cell stack 101 is open to the fuel gas discharge header 219. The fuel gas supply header 217 guides the fuel gas supplied from the fuel gas supply branch pipe 207a through the fuel gas supply hole 231a into the base pipe 105 of the plurality of cell stacks 101 at a substantially uniform flow rate. The power generation performance of the cell stack 101 is made substantially uniform.

  The fuel gas discharge header 219 is an area surrounded by the lower casing 229b and the lower tube plate 225b of the SOFC cartridge 203. The fuel gas discharge header 219 communicates with the fuel gas discharge branch pipe 209a through a fuel gas discharge hole 231b provided in the lower casing 229b. In the fuel gas discharge header 219, the other end of the cell stack 101 is disposed so that the inside of the base tube 105 of the cell stack 101 is open to the fuel gas discharge header 219. The fuel gas discharge header 219 collects the exhaust gas supplied to the fuel gas discharge header 219 through the inside of the base tube 105 of the plurality of cell stacks 101, and the fuel gas is discharged via the fuel gas discharge hole 231b. It leads to the discharge branch pipe 209a.

  Corresponding to the power generation amount of the SOFC module 201, a predetermined gas composition and a predetermined flow rate of oxidizing gas are branched to the oxidizing gas supply branch pipe and supplied to a plurality of SOFC cartridges 203. The oxidizing gas supply header 221 is an area surrounded by the lower casing 229b, the lower tube plate 225b, and the lower support 227b of the SOFC cartridge 203. The oxidizing gas supply header 221 is communicated with an oxidizing gas supply branch pipe (not shown) of the oxidizing gas supply pipe through an oxidizing gas supply hole 233a provided in the lower casing 229b. The oxidizing gas supply header 221 supplies a predetermined flow rate of oxidizing gas supplied from the oxidizing gas supply pipe via the oxidizing gas supply hole 233a to the power generation chamber 215 via an oxidizing gas supply gap 235a described later. It is a guide.

  The oxidizing gas discharge header 223 is an area surrounded by the upper casing 229a, the upper tube plate 225a, and the upper support 227a of the SOFC cartridge 203. The oxidizing gas discharge header 223 communicates with the oxidizing gas discharge pipe through an oxidizing gas discharge hole 233b provided in the upper casing 229a. This oxidant gas discharge header 223 is shown through the oxidant gas discharge hole 233b for the oxidant gas supplied from the power generation chamber 215 to the fuel gas discharge header 223 via the oxidant gas discharge gap 235b described later. Not lead to the oxidizing gas discharge pipe.

  The upper tube plate 225a is arranged between the top plate of the upper casing 229a and the upper heat insulator 227a so that the upper tube plate 225a, the top plate of the upper casing 229a and the upper heat insulator 227a are substantially parallel to each other. It is fixed to the side plate. The upper tube sheet 225a has a plurality of holes corresponding to the number of cell stacks 101 provided in the SOFC cartridge 203, and the cell stacks 101 are inserted into the holes, respectively. The upper tube sheet 225a hermetically supports one end of the plurality of cell stacks 101 through one or both of a sealing member and an adhesive member, and also includes a fuel gas supply header 217 and an oxidizing gas discharge header 223. And is to be isolated.

  The lower tube plate 225b is disposed on the side plate of the lower casing 229b so that the lower tube plate 225b, the bottom plate of the lower casing 229b, and the lower heat insulator 227b are substantially parallel between the bottom plate of the lower casing 229b and the lower heat insulator 227b. It is fixed. The lower tube sheet 225b has a plurality of holes corresponding to the number of cell stacks 101 provided in the SOFC cartridge 203, and the cell stacks 101 are inserted into the holes, respectively. The lower tube sheet 225b hermetically supports the other end of the plurality of cell stacks 101 through one or both of a sealing member and an adhesive member, and also includes a fuel gas discharge header 219 and an oxidizing gas supply header 221. And is to be isolated.

  The upper heat insulator 227a is disposed at the lower end of the upper casing 229a so that the upper heat insulator 227a, the top plate of the upper casing 229a and the upper tube plate 225a are substantially parallel to each other, and is fixed to the side plate of the upper casing 227a. Yes. Further, the upper heat insulator 227a is provided with a plurality of holes corresponding to the number of cell stacks 101 provided in the SOFC cartridge 203. The diameter of the hole is set larger than the outer diameter of the cell stack 101. The upper heat insulator 227a has an oxidizing gas discharge gap 235b formed between the inner surface of this hole and the outer surface of the cell stack 101 inserted through the upper heat insulator 227a.

  The upper heat insulator 227a separates the power generation chamber 215 and the oxidizing gas discharge header 223, and the atmosphere around the upper tube sheet 225a is heated to lower the strength and to be corroded by the oxidizing agent contained in the oxidizing gas. Suppresses the increase. The upper tube sheet 225a and the like are made of a metal material having high temperature durability such as Inconel, but the upper tube sheet 225a and the like are exposed to the high temperature in the power generation chamber 215, and the temperature difference in the upper tube sheet 225a and the like becomes large. This prevents thermal deformation. The upper heat insulator 227a guides the exhaust oxidizing gas exposed to a high temperature through the power generation chamber 215 to the oxidizing gas discharge header 223 through the oxidizing gas discharge gap 235b.

  According to the present embodiment, the structure of the SOFC cartridge 203 described above allows the fuel gas and the oxidizing gas to flow oppositely on the inner side and the outer side of the cell stack 101. As a result, the exhaust oxidizing gas exchanges heat with the fuel gas supplied to the power generation chamber 105 through the inside of the base tube 105, and the upper tube plate 225a made of a metal material is buckled. It is cooled to a temperature that does not cause deformation and supplied to the oxidizing gas discharge header 223. In addition, the temperature of the fuel gas is raised by heat exchange with the exhaust oxidizing gas discharged from the power generation chamber 215 and supplied to the power generation chamber 215. As a result, the fuel gas preheated to a temperature suitable for power generation can be supplied to the power generation chamber 215 without using a heater or the like.

  The lower heat insulator 227b is disposed at the upper end of the lower casing 229b so that the lower heat insulator 227b, the bottom plate of the lower casing 229b, and the lower tube plate 225b are substantially parallel to each other, and is fixed to the side plate of the upper casing 227a. . Also, the lower heat insulator 227b is provided with a plurality of holes corresponding to the number of cell stacks 101 provided in the SOFC cartridge 203. The diameter of the hole is set larger than the outer diameter of the cell stack 101. The lower heat insulator 227b has an oxidizing gas supply gap 235a formed between the inner surface of this hole and the outer surface of the cell stack 101 inserted through the lower heat insulator 227b.

  The lower heat insulator 227b separates the power generation chamber 215 and the oxidizing gas supply header 221. The atmosphere around the lower tube sheet 225b is heated to reduce the strength and corrosion due to the oxidizing agent contained in the oxidizing gas. Suppresses the increase. The lower tube plate 225b and the like are made of a metal material having high temperature durability such as Inconel. However, the lower tube plate 225b and the like are exposed to a high temperature and the temperature difference in the lower tube plate 225b and the like is increased, so that the heat is deformed. It is something to prevent. The lower heat insulator 227b guides the oxidizing gas supplied to the oxidizing gas supply header 233 to the power generation chamber 215 through the oxidizing gas supply gap 235a.

  According to the present embodiment, the structure of the SOFC cartridge 203 described above allows the fuel gas and the oxidizing gas to flow oppositely on the inner side and the outer side of the cell stack 101. As a result, the exhaust fuel gas that has passed through the power generation chamber 215 through the inside of the base tube 105 undergoes heat exchange with the oxidizing gas supplied to the power generation chamber 215, and the lower tube plate 225b made of a metal material. Are cooled to a temperature that does not cause deformation such as buckling, and supplied to the fuel gas discharge header 219. The oxidizing gas is heated by heat exchange with the exhaust fuel gas and supplied to the power generation chamber 215. As a result, the oxidizing gas heated to the temperature required for power generation can be supplied to the power generation chamber 215 without using a heater or the like.

  The DC power generated in the power generation chamber 215 is led out to the vicinity of the end of the cell stack 101 by the lead film 115 made of Ni / YSZ or the like provided in the plurality of SOFC cells 105, and then the current collector rod (not shown) of the SOFC cartridge 203 ) Through a current collector plate (not shown) and taken out of each SOFC cartridge 203 (outside of the cartridge). The electric power derived to the outside of the SOFC cartridge 203 by the current collector rod is connected to the generated power of each SOFC cartridge 203 in a predetermined series number and parallel number, and is derived to the outside of the SOFC module 201. It is converted into predetermined AC power by an inverter that does not, and supplied to the power load.

[2. First Embodiment]
Next, the SOFC cartridge of the first embodiment will be described.
(Configuration of SOFC cartridge)
As shown in FIG. 2, in the SOFC cartridge 203, the upper casing 229a of the fuel gas supply header 217 is provided with an inert gas supply hole 11 for supplying an inert gas AG from the outside in the central region of the horizontal plane. In the cross-sectional view of FIG. 2, an inert gas supply hole 11 is provided at the approximate center in the horizontal longitudinal direction (left-right direction in FIG. 2). Further, the fuel gas supply hole 231a is provided so that the fuel gas FG can be supplied into the fuel gas supply header 217 from the peripheral region with respect to the inert gas supply hole 11 in the central region. In the example shown in the sectional view of FIG. 2, the fuel gas supply header 217 is provided on the left and right in the horizontal longitudinal direction. The supply direction of the fuel gas is supplied from above in the drawing. However, the supply direction is not limited to this. For example, the supply direction may be supplied from the horizontal direction.

  An inert gas supply pipe (not shown) is connected to the inert gas supply hole 11, and the inert gas supply pipe is piped from an inert gas supply source (not shown) such as an inert gas tank outside the pressure vessel 205. An inert gas amount adjusting valve (inert gas amount adjusting means) 12 (FIG. 4) that is a valve that adjusts the flow rate of the inert gas is provided in a portion of the inert gas supply pipe outside the pressure vessel 205. See). An inert gas supply device (inert gas supply means) 10 is constituted by an inert gas supply source, an inert gas supply pipe, a flow rate adjusting valve 12, an inert gas supply hole 11, and the like.

The power generation reaction in the power generation unit of the SOFC cell 105 of the cell stack 101 is performed by reacting a fuel gas supplied from the fuel electrode 109, for example, a mixed gas of methane (CH ₄ ) and water vapor, and hydrogen (H ₂ ) and monoxide. The fuel electrode 109 is reformed into carbon (CO), and the fuel electrode 109 supplies oxygen ions (O) supplied through the solid electrolyte 111 to hydrogen (H ₂ ) and carbon monoxide (CO) obtained by the reforming. ^2- ) Electrochemically react with) to produce water (H ₂ O) and carbon dioxide (CO ₂ ), and at this time, electricity is generated by electrons released from oxygen ions. In addition, part of the electrochemical reaction becomes heat energy and heat is generated to increase the temperature of the SOFC cell 105. On the other hand, the modification by the mixed gas of methane (CH ₄ ) and water vapor (H ₂ O) occurs. In the quality reaction, heat is absorbed and the temperature of the SOFC cell 105 is reduced, and further, the temperature of the SOFC cell 105 is reduced by heat exchange with the oxidizing gas and heat transfer to surrounding structures. As a result of heat transfer or the like, the temperature of the SOFC cell 105 rises or falls.

Here, the inert gas supplied to the central region of the horizontal plane of the upper casing 229a of the fuel gas supply header 217 of the SOFC cartridge 203 directly contributes as a raw material for the electrochemical power generation reaction in the power generation section of the cell stack 101. When this inert gas is supplied to the cell stack 101, the amount of fuel gas supplied to the cell stack 101 (hydrogen (H ₂ ) and monoxide directly contributing to the electrochemical power generation reaction) Carbon (CO) partial pressure) is reduced, the amount of conversion of fuel gas into electrical energy is reduced, and the generated power is reduced. The calorific value of the thermal energy generated during the electrochemical reaction during power generation is reduced, but on the other hand, the reforming reaction by the mixed gas of methane (CH ₄ ) and water vapor (H ₂ O) is also reduced. The endothermic amount decreases. As a balance between the heat generation and the heat absorption, the temperature increase due to the heat generation in the cell stack 101 is suppressed, and the temperature of the SOFC cell 105 is lower than that of the cell stack 101 that does not supply the inert gas.
For example, water (H ₂ O) or nitrogen (N ₂ ) can be used as the inert gas. However, towards the water (H 2 _O), the influence of the equilibrium constant Kp of the generator voltage (SOFC cell electromotive force), the ease of supply, it is preferable for water (H 2 _O) in an inert gas .

  In the SOFC cartridge 203, when the inert gas is not supplied to the fuel gas, a portion having the highest temperature is set as the specific region. This specific region is the cell stack 101 installed in the central region of the fuel gas supply header 217 in the horizontal plane direction, and is a region in the central portion in the axial direction where the temperature of the cell stack 101 is the highest temperature. Since the inert gas supply hole 11 is arranged so as to correspond to a cell stack (in this embodiment, the horizontal central region of the upper casing 229a) installed in a specific region of the SOFC cartridge 203, the inert gas supply hole 11 of the upper casing 229a More inert gas is supplied to the cell stack 101 located near the inert gas supply hole 11 in the central region in the horizontal direction. In the cross section of FIG. 2, the cell stack 101 located in the central region in the horizontal longitudinal direction of the SOFC cartridge 203 has a higher temperature than that of the end portion in the horizontal longitudinal direction. In 101, although the supply amount of the fuel gas is reduced by the amount of the inert gas supplied, the generated power is slightly reduced, but the temperature rise due to the heat generated in the electrochemical reaction during power generation is suppressed, The effect of relatively lowering the temperature of the central portion in the longitudinal direction of the cell stack 101 is obtained.

Here, the influence on the power generation by the supply of the inert gas in the cell stack 101 when hydrogen (H ₂ ) gas is used as the fuel gas will be described using the Nernst equation.
In this case, the electrochemical during power generation is as follows.
Air electrode: 1/2 · O ₂ + 2e (electrons) → (O ²⁻ )
Fuel electrode: H ₂ + (O ²⁻ ) → H ₂ O + 2e (electrons)
Overall reaction: H ₂ + 1/2 · O ₂ → H ₂ O
The electromotive force (SOFC cell electromotive force) generated by the SOFC cell 105 is calculated from the standard potential when the reaction is in thermal equilibrium as shown in the following equation (1).

Therefore, the hydrogen partial pressure (H ₂ partial pressure) on the fuel electrode side can be adjusted by mixing an inert gas into the supplied fuel gas, and the SOFC cell electromotive force is thereby changed. Further, if water vapor (H ₂ O) is used as the inert gas to be supplied, the SOFC cell electromotive force is changed by affecting the equilibrium constant (Kp). If the SOFC cell electromotive force changes, the generated power changes, and the heat generated by the electrochemical reaction during power generation also changes. Although the generated power is reduced, the heat generated by the power generation is also reduced, so that an increase in the temperature of the cell stack 101 can be suppressed.

Next, the SOFC cartridge control device of the first embodiment will be described.
(Control device for SOFC cartridge)
As shown in FIG. 4, the present control device includes a fuel gas amount adjusting valve (fuel gas amount adjusting means) 13 for adjusting the supply amount (flow rate) of fuel gas supplied to the fuel gas supply header 217, and an inert gas supply. The temperature of the inert gas amount adjusting valve 12 of the apparatus 10 and the temperature of a specific region (the cell stack 101 installed in the central region in the horizontal plane direction of the fuel gas supply header 217 and the central region in the axial direction of the cell stack 101) are representative. A temperature sensor (temperature acquisition means) 21 that acquires temperature T as a temperature, a power information sensor (generated power acquisition means) 22 that acquires generated power P by the SOFC cartridge 203, a fuel gas amount adjustment valve 13, and an inert gas amount A controller (control means) 20 for controlling the regulating valve 12 is provided.

  The specific region is a region where the temperature becomes highest in the SOFC cartridge 203 when power generation is performed without supplying an inert gas. Of the plurality of cell stacks 101 in the SOFC cartridge 203, the SOFC cartridge 203 is a specific region. The cell stack 101 is in the center region in the horizontal plane direction of the (fuel gas supply header 217), and the region in the middle portion in the axial direction of the cell stack 101 has the highest temperature in the SOFC cartridge 203. Therefore, the controller (control means) 20 controls each flow rate adjusting valve so that the temperature distribution in the SOFC cartridge 203 becomes more uniform by setting the temperature T in the specific region to the temperature in the target range.

  In the present embodiment, the temperature sensor 21 is used as the temperature acquisition unit. However, the temperature acquisition unit is not limited to this, and the temperature T in a specific region may be estimated. For example, the temperature in the specific area correlates with the state of the SOFC cartridge 203 such as the generated power P, pressure, fuel utilization rate, and air utilization rate, so this correlation is acquired and stored in advance and the correlation is used. Then, the temperature T in the specific region may be estimated and acquired from the states of the generated power P, pressure, fuel utilization rate, and air utilization rate.

In the present embodiment, the temperature acquisition means (temperature sensor 21) is installed in the specific area when the temperature T of the specific area is set as the control target. However, the measurement position of the temperature acquisition means is not limited to this. From the measured temperature of a relatively low temperature atmosphere near the fuel gas supply header 217, such as the fuel gas pressure, the fuel usage rate, the air usage rate, etc. The temperature T of the specific region may be estimated in consideration of the influence.
Further, in order to confirm that the temperature distribution of each cell stack 101 of the SOFC cartridge 203 is a more uniform temperature, both end portions of the intermediate portion including the axial intermediate portion of the cell stack 101 (the left and right portions on the paper surface) It is further preferable that a thermometer for measurement is installed near the upper and lower ends of the same cell stack 101 and the temperature distribution of the cell stack 101 can be monitored.

  Based on the acquired temperature T of the specific area and the acquired generated power P, the controller 20 holds each temperature of the SOFC cartridge 203 by holding the temperature T of the specific area within a preset set temperature area. The temperature distribution of the stack 101 is made more uniform. As will be described later, the fact that the temperature distribution of each cell stack 101 becomes more uniform is determined by the maximum amount of generated power P. Thus, in order to set the temperature T in the specific region as a control target, the fuel gas amount adjusting valve 13 is adjusted to control the supply amount of the fuel gas, and the inert gas amount adjusting valve 12 is adjusted to adjust the inert gas. Control the amount of supply.

  In addition, when measurement thermometers are installed in the vicinity of both upper and lower ends of the plurality of cell stacks 101 in the SOFC cartridge 203, the temperature distribution of each cell stack 101 is measured by each measurement thermometer. The uniformity may be confirmed by measuring the distribution. Further, the uniformity of the temperature distribution of each cell stack 101 is determined using both the maximum generated power P and the temperature distribution measurement results obtained by the measurement thermometers of the plurality of cell stacks 101. Also good.

  The set temperature range is a relatively high temperature range of about 700 to 1000 ° C. that is a management temperature range during steady operation of the SOFC module 201, and can be set to 850 to 950 ° C., for example. In this way, the upper limit of the set temperature region is 950 ° C., which is lower than the upper limit of 1000 ° C. of the management temperature range, because the temperature T of the specific region is a predetermined temperature difference (here 50 ° C.) This is because it is preferable to ensure the long-term durability of the cell stack 101.

  In addition, when the temperature T of the specific region is lowered, the temperature of the region adjacent to the specific region where the inert gas is not supplied may be higher than the temperature T of the specific region. The temperature is decreased by a predetermined temperature difference (here, 50 ° C.) because this is preferable in order to suppress damage to each device of the SOFC cartridge 203.

When the supply amount of the inert gas is increased, the partial pressure of the fuel gas (partial pressure of hydrogen (H ₂ ) and carbon monoxide (CO)) is lowered, and the temperature T in the specific region is lowered. On the other hand, the higher the temperature of the cell stack 101, the higher the SOFC power generation amount. Therefore, when the fuel gas supply amount is increased, the SOFC electrochemical reaction amount increases and the SOFC cartridge 203 generated power P increases. At the same time, the heat generation increases, the temperature T of the specific region rises, the temperature of each cell stack 101 also rises, and the generated power P further increases. If the supply amount of the fuel gas is continuously increased as it is, the temperature of each device of the SOFC cartridge 203 including the specific region also rises and exceeds the use limit temperature at any point of the SOFC cartridge 203. Therefore, the supply amount of the fuel gas Is stopped and the supply amount of the inert gas is increased, so that the temperature of each device of the SOFC cartridge 203 including the specific region is also suppressed from increasing.

Therefore, the control by the controller (control means) 20 for this is performed as follows.
(Step 1) While the inert gas is not supplied, the fuel gas amount adjusting valve 13 is controlled to increase the supply amount of the fuel gas, and the power conditioner is controlled to increase the generated current of the SOFC cartridge 203. The current and voltage are set to predetermined values.
(Step 2) When the temperature T of the specific region approaches the upper limit of the set temperature region by the temperature sensor (temperature acquisition means) 21, the fuel gas amount adjustment valve 13 is controlled to maintain the supply amount of fuel gas, and the power Control the conditioner to maintain the generated current and voltage.
Further, the supply of the inert gas is started by controlling the inert gas amount adjusting valve 12.
(Step 3) The inert gas amount adjusting valve 12 is controlled to supply the inert gas, and the supply amount of the inert gas is increased.
Then, the temperature sensor (temperature acquisition means) 21 confirms a decrease in the temperature T in the specific region. The supply amount of the inert gas is increased, and the temperature distribution in the horizontal plane direction in the SOFC cartridge 203 is made uniform.
(Step 4) When the temperature T of the specific region is stabilized within the preset temperature range, the increase in the supply amount of the inert gas is terminated, the supply amount of the inert gas is maintained, and the temperature T of the specific region is maintained. Is held within a preset temperature range. The temperature of the specific area that has shown the maximum temperature is lowered, and the temperature difference from the relatively cool area of the cell stack 101 is reduced. Therefore, the temperature distribution between the cell stacks 101 in the SOFC cartridge 203 becomes small.
(Step 5) Maintaining the supply amount of the inert gas and increasing the supply amount and current of the fuel gas by a small amount again to increase the temperature of each cell stack 101 in the SOFC cartridge 203 as a whole, The generated power P is improved as compared with the conventional case.
(Step 6) By maintaining the supply amount of the inert gas and increasing the fuel gas supply amount and the generated current and voltage, the temperature T of the specific region reaches the upper limit of the preset temperature range, The fuel gas supply amount, current and voltage increase are terminated, and the fuel gas supply amount, current and voltage are maintained.
(Step 7) The operations from Step 2 to Step 6 are repeated. The controller (control means) 20 controls the generated electric power P more than before while keeping the temperature T of the specific region within a preset temperature range. The fact that the temperature distribution of each cell stack 101 in the SOFC cartridge 203 becomes more uniform is determined by gradually increasing the supply amount of the inert gas and maximizing the generated power P. Further, when the temperatures of the plurality of cell stacks 101 in the SOFC cartridge 203 are measured, it may be determined that the measured temperature distribution becomes more uniform.
Here, maximizing the generated power P does not mean that the generated power P is strictly the maximum point, but the generated power P can be increased or decreased even if the supply amount of the inert gas is increased or decreased within a minute range. This means that the generated power P is in an area near the maximum (maximum area) that can be determined when there is no change.

  That is, when the supply amount of the inert gas is increased, the cell stack 101 to which the inert gas is supplied causes a slight decrease in generated power in exchange for the effect of decreasing the temperature of the cell stack 101. Since the temperature of the specific area where the temperature has been shown is lowered and the temperature between the cell stacks 101 is made uniform, the amount of fuel gas supplied to the fuel gas supply head 217 can be increased, which is inactive. In the cell stack 101 to which no gas is supplied and the cell stack 101 with a small supply amount of inert gas, in addition to the increase in the supply amount of the fuel gas, power generation is performed according to the temperature rise in the relatively low temperature portion of the cell stack 101. The electric power P increases.

In addition, when the supply amount of the inert gas is increased in this way, in the cell stack 101 to which the inert gas is supplied, the generated power is greatly reduced, and the temperature of the specific region is further reduced, so that each cell The temperature between the stacks 101 becomes rather uneven, which is not preferable. Therefore, control is performed so that the temperature T in the specific region does not fall below the lower limit in the preset temperature range so that the influence of the decrease in the generated power P in the cell stack 101 to which the inert gas is supplied does not increase. Do.
At this time, the fact that the temperature distribution of each cell stack 101 in the SOFC cartridge 203 becomes more uniform means that the supply amount of the inert gas is gradually increased and the generated power P becomes the maximum region (near the maximum). Judge by. Further, when the temperatures of the plurality of cell stacks 101 in the SOFC cartridge 203 are measured, it may be determined that the measured temperature distribution becomes more uniform. Therefore, control can be performed so that the generated power P becomes maximum.

(Function and effect)
According to the SOFC cartridge 203 and the control device 20 of the SOFC cartridge 203 according to the first embodiment, a specific region (here, the central region of the horizontal plane of the SOFC cartridge 203) of the plurality of cell stacks 101 that has a relatively high temperature. Since the inert gas is supplied from the outside to the cell stack 101 installed in the axially intermediate portion of the installed cell cartridge), the inert gas is supplied to the cell stack 101 in the specific area. The amount of fuel gas supplied (the partial pressure of the fuel gas is reduced) is reduced, the generated power P is reduced, and the amount of heat generated by the power generation reaction is also reduced. The temperature distribution in the horizontal direction and the longitudinal direction of the cell cartridge can be made uniform.

  FIGS. 5A and 5B are diagrams for explaining the effect of supplying this inert gas. FIG. 5A shows that the fuel gas is uniformly supplied to each cell stack 101 without supplying the inert gas. FIG. 5 (b) shows the temperature distribution characteristic (curve A) in the case of (comparative example). FIG. 5 (b) shows the present embodiment in which an inert gas is supplied to the cell stack 101 in which a small part of the cell stack is installed in a specific region. The temperature distribution characteristics (curves B and C) are shown corresponding to the cell stacks 101 of the SOFC cartridge 203, respectively. That is, the temperature distribution characteristic in the horizontal longitudinal direction in a cross section perpendicular to the horizontal plane including the center of the horizontal plane of the SOFC cartridge 203 is shown.

  As shown by the curve A in FIG. 5A, when the fuel gas is uniformly supplied to each cell stack 101, the temperature of the cell stack 101 located in the central region in the horizontal longitudinal direction of the SOFC cartridge 203 becomes high, and the upper limit temperature Close to. Each cell stack 101 generates heat due to a power generation reaction and the temperature of the power generation unit rises. However, since there is no power generation unit at both ends in the longitudinal direction of the cell stack 101, heat generation does not occur. In addition, since the end of the fuel cell stack tends to dissipate heat to the outside of the cartridge, cooling is promoted.

  For this reason, the central portion of the cell stack 101 is likely to be heated to a relatively high temperature due to the heat generated during the power generation reaction of the power generation portion and being difficult to dissipate to the surroundings, and both ends of the fuel cell stack are at the central portion. In comparison, the temperature rise is relatively small, a temperature difference occurs in the longitudinal direction of the fuel cell stack, and the temperature of the cell stack 101 increases as it moves away from the horizontal central area of the SOFC cartridge 203 and approaches the left and right ends of the page. Becomes cold.

  Since the power generation efficiency (power generation output) is affected by the cell stack temperature, the power generation efficiency (power generation output) is low because the internal resistance of the SOFC cell 105 is high and the power generation reaction is low in the low temperature portion. Therefore, in the cross section of the fuel cell stack of FIG. 5, if the temperature of the cell stack 101 in the central region in the horizontal longitudinal direction of the SOFC cartridge 203 is to be kept below the upper limit temperature, the cells on both ends in the horizontal longitudinal direction of the SOFC cartridge 203 In the stack 101, the generated power is reduced by the relatively low temperature compared to the cell stack 101 in the central region in the horizontal longitudinal direction.

  In the cross section of the fuel cell stack in FIG. 5, the SOFC that collects the power generation output of each cell stack 101 in the entire SOFC cartridge 203 as the temperature difference between the central region and both ends in the horizontal longitudinal direction of the SOFC cartridge 203 occurs. The generated power P of the cartridge 203 cannot be increased.

  In contrast, as shown by a curve B in FIG. 5B, when an inert gas is supplied to the cell stack 101 in the specific region, the temperature of the cell stack 101 in the central region in the horizontal longitudinal direction of the SOFC cartridge 203 is suppressed. Thus, the cell stack 101 in which a part of the cell stack is installed in the specific area generates a margin of temperature that allows the temperature to rise with respect to the preset upper limit temperature of the set temperature area. That is, the high temperature portion generated in the central region in the horizontal longitudinal direction of the SOFC cartridge 203 is lowered, and the temperature in the relatively low temperature region at both end portions does not change. The temperature difference in the horizontal longitudinal direction of the SOFC cartridge 203 is made uniform. Therefore, as shown by curve C in FIG. 5B, the temperature of each cell stack 101 can be suppressed to the upper limit temperature or less while increasing the amount of fuel gas supplied to the SOFC cartridge 203 to increase the power generation output. it can.

  Although not shown, the axial direction of the cell stack 101 in which at least a part of the cell stack is installed in a specific region is also similar to the horizontal longitudinal direction of the SOFC cartridge 203 and is generated near the central portion in the axial direction. In addition, the temperature in the high temperature region is lowered, and the SOFC cell 105 is not originally provided in the upper and lower end portions of the cell stack 101. Therefore, the temperature in the relatively low temperature region in the upper and lower end portions does not change. Therefore, the axial temperature difference of the SOFC cartridge 203 is made uniform in the cross section of the fuel cell stack in FIG. Also in the axial temperature distribution of each cell stack 101, the temperature of each cell stack 101 can be kept below the upper limit temperature while increasing the amount of fuel gas supplied to increase the power generation output.

  As described above, according to the SOFC cartridge 203 and the control device 20 of the SOFC cartridge 203, the cell stack 101 that is at least partially installed in a specific region that is relatively high in temperature among the plurality of cell stacks 101 is externally connected. Since the inert gas is supplied from the fuel cell to reduce the temperature in a specific region (the temperature distribution between the cell stacks is made uniform), and the fuel gas supply amount in the entire SOFC cartridge 203 can be increased. While managing the temperature of the cell stack 101 within the set temperature range, the generated power P in the entire SOFC cartridge 203 can be increased, and the power generation efficiency can be increased.

[4. Second Embodiment]
(Configuration of SOFC cartridge)
As shown in FIG. 6, the SOFC cartridge 203 according to the second embodiment has a horizontal plane direction (horizontal longitudinal direction in the cross-sectional view of FIG. 6 (left and right direction in the drawing)) of the upper casing 229 a of the fuel gas supply header 217. ) Is provided with an inert gas supply pipe 11A for supplying an inert gas AG from the outside. Similarly to the first embodiment, the fuel gas supply hole 231a is provided so that the fuel gas FG can be supplied into the fuel gas supply header 217 from the surrounding area. FIG. 6 illustrates the fuel gas supply header 217 provided on the left and right in the horizontal longitudinal direction so as to sandwich the inert gas supply hole 11.

The inert gas supply pipe 11A is branched into a plurality of inert gas supply branch pipes 11a inside the fuel gas supply header 217, and each of the inert gas supply branch pipes 11a has a specific region (in the horizontal direction of the upper casing 229a). It is inserted into a fuel gas flow path that is at least partially installed at a relatively high temperature in the central region and communicates with a fuel electrode 109 provided inside the cell stack 101. The tip of the inert gas supply branch pipe 11a is open in the middle region in the flow direction in the fuel gas flow channel of the cell stack 101, and is preferably in the central region or in front thereof, and the fuel gas is supplied in the longitudinal direction of the cell stack 101. From the header 217 side, a position of about 1/3 to about 1/2 (intermediate position) of the total length of the cell stack 101 is more preferable.
Note that the inert gas supply device (inert gas supply means) 10A is configured in the same manner as in the first embodiment, and a description thereof will be omitted.

(Function and effect)
According to the SOFC cartridge 203 and the control device for the SOFC cartridge 203 according to the second embodiment, as in the first embodiment, the cell stack 101 in the specific region that is at a relatively high temperature among the plurality of cell stacks 101 is used. Since the inert gas is supplied from the outside to lower the temperature in the specific region and the fuel gas supply amount in the entire SOFC cartridge 203 can be increased, the temperature of each cell stack 101 is managed within the set temperature region. However, the generated power P in the entire SOFC cartridge 203 can be increased, and the power generation efficiency can be increased.

  Furthermore, in the SOFC cartridge 203 according to the second embodiment, the inert gas supply branch pipe 11a is inserted into the fuel gas flow path of the cell stack 101 in the specific region, and the flow path in the fuel gas flow path of the cell stack 101 is Since the opening is in the central region in the direction or in front of this, the power generation reaction is suppressed in the region in the middle portion in the axial direction where the temperature is highest in one cell stack 101, and the temperature rise in this portion can be suppressed. The temperature difference in the longitudinal direction of the cell stack 101 can be further reduced. Accordingly, the total generated power P of the SOFC cartridge 203 can be increased more efficiently, and the power generation efficiency can be increased.

[5. Others]
As mentioned above, although embodiment of this invention was described, this invention can be implemented by changing suitably each embodiment in the range which does not deviate from the meaning of this invention.
For example, it is also effective to implement the first embodiment and the second embodiment in combination.

  In the above embodiment, the SOFC cartridge 203 is described as a single unit. However, the SOFC cartridge control device and the control method may be configured so that each SOFC cartridge 203 in the fuel cell module 201 is individually controlled. The SOFC cartridge control device and control method may be configured to obtain the temperature T and the generated power P from some SOFC cartridges 203 in the fuel cell module 201 and control the SOFC cartridges 203 in cooperation with each other. .

In this embodiment, the inert gas is supplied to the cell stack in the central region in the horizontal direction of the SOFC cartridge. However, the cell stack that supplies the inert gas is a cell stack in a region where the temperature is relatively high. In that case, it is not necessarily limited to the central region in the horizontal direction of the SOFC cartridge.
Furthermore, in the second embodiment, the inert gas supply branch pipe 11a supplies the fuel gas flow path in the fuel gas flow path of the cell stack 101 in the flow direction central region or in front thereof. It suffices if priority is given to supplying a relatively high temperature area in the gas flow path, and it is not limited to the central area of the fuel gas flow path but may be an appropriate intermediate area.

10, 10A inert gas supply device (inert gas supply means)
11 Inert gas supply hole 11A Inert gas supply pipe 11a Inert gas supply branch pipe 12 Inert gas amount adjusting valve (inert gas amount adjusting means)
13 Fuel gas amount adjusting valve (Fuel gas amount adjusting means)
20 controller (control means)
21 Temperature sensor (temperature acquisition means)
22 Power information sensor (generated power acquisition means)
101 Fuel cell stack (cell stack)
201 Fuel cell module (SOFC module)
203 Fuel cell cartridge (SOFC cartridge)
205 Pressure vessel (module vessel)
215 Power generation chamber 217 Fuel gas supply header (fuel gas supply chamber)
219 Fuel gas discharge header (fuel gas discharge chamber)
AG Inert gas FG Fuel gas

Claims (9)

A plurality of fuel cell stacks;
A fuel gas supply header disposed on one end side of the plurality of fuel cell stacks and supplying fuel gas supplied from the outside of the cartridge to the inside of the fuel cell stack;
A fuel gas discharge header that is disposed on the other end side of the plurality of fuel cell stacks and discharges the fuel gas discharged from the inside of the fuel cell stack to the outside of the cartridge;
With
An inert gas supply means for supplying an inert gas from the outside of the cartridge is provided in a fuel cell stack in a specific region where the temperature is relatively high among the plurality of fuel cell stacks. Fuel cell cartridge.   2. The specific region is a central region in a plane direction perpendicular to the axial direction of the fuel cell cartridge and includes at least part of the central region in the axial direction of the fuel cell cartridge. Fuel cell cartridge.   The inert gas supply means has an inert gas opened at a corresponding location so as to supply the inert gas to a fuel cell stack having at least a part installed in the specific area in the fuel gas supply header. 3. The fuel cell cartridge according to claim 1, further comprising a supply hole.   The inert gas supply means includes an inert gas supply branch pipe inserted into a fuel gas flow path provided in the fuel cell stack at least a part of which is installed in the specific region. Item 3. The fuel cell cartridge according to Item 1 or 2.   The tip opening of the inert gas supply branch pipe is disposed in an intermediate region in the flow direction in the fuel gas flow channel of the fuel cell stack in the specific region. Fuel cell cartridge.   The fuel cell cartridge according to claim 1, wherein the inert gas contains nitrogen gas or water vapor.   A fuel cell module comprising a plurality of fuel cell cartridges according to any one of claims 1 to 6 in a module container. A control device for controlling the plurality of fuel cell stacks in the fuel cell cartridge according to any one of claims 1 to 6,
A fuel gas amount adjusting means for adjusting a supply amount of the fuel gas to the fuel gas supply header;
An inert gas amount adjusting means which is provided in the inert gas supply means and adjusts the supply amount of the inert gas;
Temperature acquisition means for acquiring the temperature of the specific region;
Generated power acquisition means for acquiring power generated by the fuel cell cartridge;
Based on the temperature of the specific area acquired by the temperature acquisition means and the generated power acquired by the generated power acquisition means, while maintaining the temperature of the specific area within a preset set temperature area And a control means for controlling the fuel gas amount adjusting means and the inert gas amount adjusting means so that the generated power is maximized. A control method for controlling the plurality of fuel cell stacks in the fuel cell cartridge according to any one of claims 1 to 6,
Fuel gas amount adjusting means for adjusting the amount of fuel gas supplied to the fuel gas supply header;
An inert gas amount adjusting means for adjusting the amount of inert gas supplied by the inert gas supplying means;
A temperature acquisition step of acquiring the temperature of the specific region;
A generated power acquisition step of acquiring generated power by the fuel cell cartridge;
Based on the temperature of the specific region acquired by the temperature acquisition step and the generated power acquired by the generated power acquisition step, the temperature of the specific region is maintained within a preset temperature range set in advance. And a control step of controlling the fuel gas amount adjusting means and the inert gas amount adjusting means so that the generated power is maximized.

Images