JP6780044B2 - How to assemble fuel cell submodule, fuel cell module and combined cycle system and submodule - Google Patents

Description

The present invention relates to a fuel cell submodule, a fuel cell module, a combined cycle power generation system, and a method for assembling the submodule.

A fuel cell that generates electricity by chemically reacting a fuel gas and an oxidizing gas is known. Of these, solid oxide fuel cells (SOFCs) use ceramics such as zirconia ceramics as the electrolyte, and are operated using city gas, natural gas, petroleum, methanol, coal gasification gas, etc. as fuel. It is a fuel cell. Such SOFCs have a high operating temperature of about 700 to 1000 ° C. in order to increase ionic conductivity, and are known as versatile and highly efficient high-temperature fuel cells. Such SOFC comprises, for example, a combined power generation system combined with an internal combustion engine such as a micro gas turbine (hereinafter referred to as "MGT"), and the compressed air discharged from the compressor is used as an oxidizing gas for SOFC. In addition to supplying to the air electrode, the high-temperature exhaust fuel gas discharged from the SOFC is supplied to the MGT combustor for combustion, and the turbine is rotated by the high-temperature combustion gas generated by the combustor to improve power generation efficiency. High power generation is possible.

At the time of power generation in SOFC, the power generation part of SOFC generates heat. The power generation unit preferably generates power in a preset temperature range from the viewpoint of power generation efficiency, durability of constituent materials, and the like.
Therefore, for example, Patent Document 1 describes a flow path connecting the internal space of the cartridge including the SOFC power generation unit and the external space of the cartridge in the pressure vessel accommodating the cartridge including the SOFC power generation unit, and this flow. A configuration including a flow rate adjusting device for adjusting the flow rate of an oxidizing gas (air) passing through a road is disclosed. According to this configuration, the flow rate of the oxidizing gas leaking from the internal space of the cartridge to the external space (the space inside the pressure vessel) is adjusted according to the temperature inside the cartridge, and the temperature inside the cartridge is adjusted to an appropriate temperature. It is kept within the range.

Japanese Unexamined Patent Publication No. 2016-91968

By the way, in order to reduce the influence on power generation even if the supply of oxidizing gas fluctuates, a part of the oxidizing gas supplied as a structure covering the outer periphery of the cartridge is the cartridge internal space and the external space (space in the pressure vessel). ), It is possible to distribute a small amount of flow. The oxidizing gas supplied into the cartridge for power generation is heated by the heat generated by the power generation unit and rises in the cartridge. At this time, a part of the oxidizing gas leaks into the external space through the gap at the top of the cartridge. The oxidizing gas leaking into the external space is cooled by heat exchanged with the outside of the pressure vessel via the pressure vessel, descends in the external space, and is sucked into the internal space of the cartridge through the gap at the bottom of the cartridge. As a result, in the pressure vessel, natural convection of the oxidizing gas is generated by the upward flow in the internal space of the cartridge and the downward flow in the external space of the cartridge. Such natural convection may dissipate heat to the outside of the pressure vessel via the pressure vessel as the oxidizing gas passes through the exterior space of the cartridge.
In recent years, the development of a larger-scale combined cycle system that combines a gas turbine with a higher output and SOFC has been progressing. Since the pressure of the air discharged from the compressor tends to increase as the output of the gas turbine increases, the operating pressure in the pressure vessel also increases in a large-scale SOFC combined power generation system. Further, increasing the operating pressure in the pressure vessel is effective for improving the power generation efficiency of the SOFC. On the other hand, when the operating pressure in the pressure vessel is increased, there is a problem that the amount of oxidizing gas leaking from the internal space of the cartridge to the external space increases. This is because the gas density increases due to the increase in operating pressure, so that the buoyancy acting on the oxidizing gas in the cartridge that has been heated in the power generation section increases, and the pressure between the oxidizing gas in the cartridge and the heat insulating material increases. This is because the loss is reduced. Due to these factors, when the operating pressure is high, the natural vs. flow rate of the oxidizing gas leaking from the cartridge internal space in the pressure vessel increases from upward to downward, and the oxidizing gas passes through the external space of the cartridge. The amount of heat released to the outside of the pressure vessel via the pressure vessel also increases. As a result, the temperature of the power generation unit in the internal space of the cartridge is lowered more than necessary, and the power generation efficiency of the SOFC is lowered.

In the configuration disclosed in Patent Document 1, the flow rate of the oxidizing gas flowing out from the internal space of the cartridge to the external space is adjusted according to the temperature inside the cartridge, but the vertical direction of the oxidizing gas in the pressure vessel is adjusted. Since the natural convection from the upper side to the lower side is generated, there is a problem that the heat is dissipated from the pressure vessel to the outside and the power generation efficiency of the SOFC is lowered. Further, when the pressurized operation is performed with the configuration disclosed in Patent Document 1, the natural convection may further increase and the power generation efficiency of the SOFC may further decrease.

The present invention has been made in view of such circumstances, and provides a fuel cell submodule, a fuel cell module, a combined power generation system, and a method for assembling the submodule, which can suppress a decrease in power generation efficiency. With the goal.

In order to solve the above problems, the following means are adopted as the method of assembling the fuel cell submodule, the fuel cell module, the combined cycle power generation system, and the submodule of the present invention.
The fuel cell submodule according to one aspect of the present invention is a fuel cell submodule housed in a pressure vessel, and is at least one cell including a fuel cell that generates power by supplying fuel gas and an oxidizing gas. It includes a stack and a side exterior plate arranged so as to surround the cell stack and defining the sides.

In the above configuration, the oxidizing gas that is about to flow into the power generation region from the side of the outer peripheral surface of the sealing member of the fuel cell submodule (hereinafter, also simply referred to as “submodule”) is first placed on the side exterior. It is hindered by the board. Since the inflow of oxidizing gas is prevented in this way, the space inside the pressure vessel is more reliably generated from the space inside the pressure vessel into the area where the fuel cell module of the submodule generates electricity (hereinafter referred to as "power generation area"). It is possible to suppress the inflow of unintended oxidizing gas. Therefore, it is possible to more reliably suppress the natural convection circulation of the oxidizing gas that circulates from above to below in the vertical direction inside the power generation area and outside the power generation area in the pressure vessel, resulting in natural convection circulation of the oxidizing gas. The resulting heat dissipation to the outside of the pressure vessel can be suppressed.
Further, when assembling the sub-module, the lateral positioning can be assembled with the side exterior plate as a reference. Therefore, the positioning work at the time of assembling can be facilitated.

Further, in the fuel cell submodule according to one aspect of the present invention, the side exterior plate may have an opening defined by the upper edge of the side exterior plate at the upper end.

In the above configuration, an opening defined by the upper edge is formed at the upper end of the lateral exterior plate. As described above, since the lid material covering the vertically upper part of the submodule is not provided, even when the members constituting the submodule are thermally expanded due to the high temperature, the thermal expansion can be allowed vertically upward. , Suppress binding submodules.

Further, the fuel cell submodule according to one aspect of the present invention may include a lower exterior plate that is connected to the lower end of the side exterior plate and closes an opening formed at the lower end of the side exterior plate.

In the above configuration, since the entire lower part of the submodule is covered with the lower outer plate, the oxidizing gas that tends to flow into the submodule from below is surely blocked by the lower outer plate. Therefore, it is possible to more reliably prevent unintended oxidizing gas from flowing into the power generation region of the submodule from the space inside the pressure vessel.
Further, when assembling the sub-module, the vertical vertical positioning can be performed with the lower exterior plate as a reference. Therefore, the positioning work at the time of assembling can be facilitated.

Further, in the fuel cell submodule according to one aspect of the present invention, the lower exterior plate is formed with a through hole, and the lower exterior plate includes a tubular member that communicates with the through hole and extends vertically downward. You may be.

In the above configuration, a through hole is formed in the lower exterior plate, and a tubular member communicating with the through hole is provided. As a result, for example, even if there is a pipe extending vertically downward from the side of the fuel gas header, the pipe can be sealed by inserting the through hole and the inside of the tubular member to seal the pipe. It can communicate with the outside. Further, since the inside of the tubular member is inserted, the portion has a double pipe structure, and even if the structure is such that the pipe penetrates the lower exterior plate, the submodule passes through the portion from the space inside the pressure vessel. It is possible to suppress the inflow of oxidizing gas into the inside.

Further, the fuel cell submodule according to one aspect of the present invention includes a pipe for inserting the inside of the tubular member, and a part of the tubular member is formed of a flexible tube having flexibility, and the flexible tube is formed. The portion formed by the pipe may be located vertically above the portion for sealing and fixing the tubular member and the pipe.

In the above configuration, a part of the tubular member is formed of a flexible tube that is flexible and allows expansion and contraction in the vertical vertical direction. As a result, even if the tubular member or pipe is thermally expanded under the influence of the high temperature in the power generation area of the submodule, the flexible pipe absorbs the expansion and contraction in the vertical vertical direction, so that the tubular member and the pipe are fixed to each other. The generated load can be reduced. A part of the pipe may also be formed of a flexible pipe having flexibility. With such a configuration, expansion and contraction in the vertical vertical direction can be absorbed even on the piping side, so that the fixed portion between the tubular member and the piping is not restrained, so that the stress generated in the piping can be further reduced. it can.

Further, in the fuel cell submodule according to one aspect of the present invention, a plurality of the cell stacks are connected, and the fuel gas is supplied to the plurality of cell stacks or the fuel gas is discharged from the plurality of cell stacks. It may include a gas header and a lower exterior plate having one end connected to the lower end of the side exterior plate and the other end connected to the side end of the fuel gas header.

In the above configuration, the bottom surface of the submodule with the fuel gas header is not covered with the lower exterior plate. Therefore, when connecting the pipe or the current collector rod to the bottom surface of the fuel gas header, the pipe or the current collector rod penetrates the lower exterior plate. It does not have to be a structure. If the structure is such that the pipes and current collector rods penetrate the lower exterior plate, it is necessary to establish a sealed structure while ensuring insulation in each pipe and current collector rod so that oxidizing gas does not flow inside the lower exterior plate. Although the structure is complicated, the above configuration allows easy connection.

Further, in the fuel cell submodule according to one aspect of the present invention, the upper surface of the lower exterior plate in the vertical direction and the bottom surface of the fuel gas header are separated in the vertical vertical direction, and the upper surface of the lower exterior plate in the vertical direction and the fuel are separated from each other. It may be connected to the bottom surface of the gas header via a sealing plate extending vertically in the vertical direction.

In the above configuration, a seal plate for connecting the upper surface of the lower exterior plate and the bottom surface of the fuel gas header is provided. As a result, it is possible to prevent the oxidizing gas from flowing in from the space while forming a space between the upper surface of the lower exterior plate and the bottom surface of the fuel gas header. Therefore, for example, even if there is a member extending vertically downward from the bottom surface of the fuel gas header, it is possible to suppress an unintended inflow of oxidizing gas into the power generation unit. As a member extending vertically downward from the bottom surface of the fuel gas header, for example, there are legs for erecting cartridges constituting the sub-module in the sub-module.

Further, the fuel cell submodule according to one aspect of the present invention includes a sealing member that surrounds at least a part of the cell stack, and each of the plurality of cell stacks has a central portion in which the fuel cell is provided. A part of the cell stack including the end portion where the fuel cell is not provided and surrounded by the sealing member is the central portion where the fuel cell is provided, and the sealing member is the inside of the sealing member. An oxidizing gas supply unit that supplies the oxidizing gas around the plurality of cell stacks, and an oxidizing gas discharging unit that discharges the oxidizing gas from the inside, and the oxidizing gas supply unit and the oxidation. The remaining portion other than the sex gas discharging portion may suppress the inflow of the oxidizing gas into the inside and the leakage of the oxidizing gas from the inside.

In the above configuration, a sealing member in the submodule surrounds a central portion where fuel cell cells of a plurality of cell stacks are provided. As a result, the power generation area can be surrounded by a sealing member. Further, in the sealing member, in the rest other than the oxidizing gas supply part and the oxidizing gas discharging part, the oxidizing gas flows into the inside of the sealing member (that is, the power generation region), and the oxidizing gas from the inside of the sealing member is charged. Since the discharge is hindered, unintended inflow and outflow of oxidizing gas can be suppressed between the space in the pressure vessel and the power generation region of the submodule. Therefore, the generation of natural convection circulation of oxidizing gas that leaks from the inside of the power generation area and circulates from above to below in the vertical direction outside the power generation area in the pressure vessel, which may occur in the space inside the pressure vessel. Can be suppressed. Therefore, it is possible to suppress heat dissipation to the outside of the pressure vessel due to the natural convection circulation of the oxidizing gas, and it is possible to suppress a decrease in the power generation efficiency of the fuel cell module.

Further, the fuel cell submodule according to one aspect of the present invention includes an oxidizing gas flow pipe that communicates with the oxidizing gas supply unit or the oxidizing gas discharging unit, and the oxidizing gas flow pipe is lateral to the side. Inside the exterior plate, it may extend vertically in the vertical direction.

In the above configuration, since the oxidizing gas flow pipe extends vertically and vertically inside the side exterior plate, the oxidizing gas flow pipe and the side exterior plate do not interfere with each other. Therefore, it is not necessary to form a structure for penetrating the oxidizing gas flow pipe in the side exterior plate, so that the configuration can be simplified. Further, for example, when a heat insulating material or the like is provided between the side exterior plate and the oxidizing gas flow pipe, the oxidizing gas flow pipe does not interfere with the heat insulating material. Therefore, since the sub-module can be formed without providing a member through which the heat insulating material is penetrated, the heat insulating material can be disassembled without being damaged when the sub-module is disassembled.

The fuel cell module according to one aspect of the present invention includes a pressure vessel and the fuel cell submodule according to any one of the above, which is housed in the pressure vessel.

The combined power generation system according to one aspect of the present invention includes the fuel cell module described above and a gas turbine that generates rotational power using the exhaust fuel gas and the oxidative gas exhausted from the fuel cell module. The fuel cell module is supplied with the oxidizing gas compressed by using the rotational power, and the plurality of cell stacks generate power by using the fuel gas and the oxidizing gas.

A method of assembling a submodule according to one aspect of the present invention includes at least one cell stack including a fuel cell that generates power by supplying a fuel gas and an oxidizing gas, and a side thereof arranged so as to surround the cell stack. It is a method of assembling a fuel cell submodule including a side exterior plate that defines the direction and a lower exterior plate that is connected to the lower end of the side exterior plate and closes an opening formed at the lower end of the side exterior plate. The connection step of connecting the side exterior plate and the lower exterior plate, and the cell stack insertion step of inserting the cell stack vertically into the side exterior plate connected in the connection step. I have.

Further, the method of assembling the sub-module according to one aspect of the present invention may further include a sealing member disposing step of disposing the sealing member so as to surround the cell stack.

Further, the method of assembling the submodule according to one aspect of the present invention may further include a submodule heat insulating material fitting step of fitting the submodule heat insulating material inside the side exterior plate and the lower exterior plate.

According to the present invention, it is possible to suppress a decrease in power generation efficiency of the fuel cell submodule.

It shows the cell stack which concerns on one Embodiment of this invention. It shows the SOFC module which concerns on one Embodiment of this invention. It shows the cross section of the SOFC cartridge which concerns on one Embodiment of this invention. It is a vertical sectional view which shows the SOFC module which concerns on one Embodiment of this invention. It is an enlarged sectional view of the V part of FIG. It is the schematic which shows the lower part of the SOFC submodule of FIG. FIG. 6 is a cross-sectional view taken along the line VII-VII of FIG. It is a perspective view which shows the seal plate of FIG. It is a figure which shows the assembly method of the SOFC submodule of FIG.

Hereinafter, an embodiment of the fuel cell submodule, the fuel cell module, the combined cycle power generation system, and the method of assembling the submodule according to the present invention will be described with reference to the drawings.
In the following, for convenience of explanation, the positional relationship of each component is shown vertically upward side and vertically downward side by using the expressions “upper” and “lower” with respect to the paper surface. Further, in the present embodiment, if the same effect can be obtained in the vertical direction and the horizontal direction with respect to the vertical direction, the vertical direction on the paper surface may correspond to the horizontal direction perpendicular to the vertical direction. Further, in the following, a cylindrical shape will be described as an example of the cell stack of the solid oxide fuel cell (SOFC), but this is not necessarily the case, and for example, a flat plate type cell stack may be used. A fuel cell is formed on a substrate, but the substrate may be formed and the electrode (fuel electrode or air electrode) may be thickly formed without the substrate, and the substrate may also be used.

First, a cylindrical cell stack using a base tube will be described as an example according to the present embodiment with reference to FIG. Here, FIG. 1 shows one aspect of the cell stack according to the present embodiment. The cell stack 101 has a cylindrical base tube 103, a plurality of fuel cell 105 formed on the outer peripheral surface of the base tube 103, and an interconnector 107 formed between adjacent fuel cell 105. The fuel cell 105 is formed by laminating a fuel electrode 109, a solid electrolyte 111, and an air electrode 113. Further, the cell stack 101 is attached to the air electrode 113 of the fuel cell 105 formed at one end of the plurality of fuel cell 105 formed on the outer peripheral surface of the base tube 103 in the axial direction of the base tube 103. A lead film 115 electrically connected via an interconnector 107 is provided, and a lead film 115 electrically connected to a fuel pole 109 of a fuel cell 105 formed at the other end of the end is provided.

Substrate tube 103 is made of a porous material, for example, CaO-stabilized _ZrO 2 (CSZ), a mixture of CSZ and nickel oxide (NiO) (CSZ + NiO) , or _Y 2 _{O 3} stabilized ZrO ₂ (YSZ), or The main component is MgAl ₂ O _{4 and the} like. The base tube 103 supports the fuel cell 105, the interconnector 107, and the lead film 115, and the fuel gas supplied to the inner peripheral surface of the base tube 103 is supplied to the inner peripheral surface of the base tube 103 through the pores of the base tube 103. It is diffused in the fuel electrode 109 formed on the outer peripheral surface of the above.

The fuel electrode 109 is composed of an oxide of a composite material of Ni and a zirconia-based electrolyte material, and for example, Ni / YSZ is used. The thickness of the fuel electrode 109 is 50 to 250 μm. In this case, in the fuel electrode 109, Ni, which is a component of the fuel electrode 109, has a catalytic action on the fuel gas. This catalytic action reacts a fuel gas supplied via the substrate 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). It is a thing. Further, the fuel electrode 109 is an interface between hydrogen (H ₂ ) and carbon monoxide (CO) obtained by reforming and oxygen ions (O ^2- ) supplied via the solid electrolyte 111 with 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 fuel cell 105 generates electricity by the electrons emitted from the oxygen ions.
The fuel gases that can be supplied and used to the fuel electrode 109 of SOFC10 include hydrocarbon gases such as hydrogen (H ₂ ), carbon monoxide (CO), and methane (CH ₄ ), city gas, and natural gas, as well as oil. Examples thereof include gas produced from carbonaceous raw materials such as methanol and coal by a gasification facility.

As the solid electrolyte 111, YSZ having airtightness that makes it difficult for gas to pass through and high oxygen ion conductivity at high temperature is mainly used. The solid electrolyte 111 moves oxygen ions ( ^O2- ) generated at the air electrode to the fuel electrode. The film thickness of the solid electrolyte 111 located on the surface of the fuel electrode 109 is 10 to 100 μm.

The air electrode 113 is composed of, for example, a LaSrMnO _3- based oxide or a LaCoO _3- based oxide. The air electrode 113 dissociates oxygen in an oxidizing gas such as air to be supplied in the vicinity of the interface with the solid electrolyte 111 to generate oxygen ions (O ^2- ).
The air electrode 113 may have a two-layer structure. In this case, the air electrode layer (air electrode intermediate layer) on the solid electrolyte 111 side is made of a material having high ionic conductivity and excellent catalytic activity. The air electrode layer (air electrode conductive layer) on the air electrode intermediate layer may be composed of a perovskite-type oxide represented by Sr and Ca-doped LaMnO ₃ . By doing so, the power generation performance can be further improved.
Oxidizing gas is a gas containing approximately 15% to 30% of oxygen, and air is typically preferable. However, in addition to air, a mixed gas of combustion exhaust gas and air, a mixed gas of oxygen and air, etc. Can be used.

The interconnector 107 is composed of a conductive perovskite-type oxide represented by M _1-x L _x TiO ₃ (M is an alkaline earth metal element and L is a lanthanoid element) such as SrTiO ₃ system. The interconnector 107 has a dense film so that the fuel gas and the oxidizing gas do not mix with each other. Further, the interconnector 107 has stable durability and electrical conductivity in both an oxidizing atmosphere and a reducing atmosphere. In the adjacent fuel cell 105, the interconnector 107 electrically connects the air pole 113 of one fuel cell 105 and the fuel pole 109 of the other fuel cell 105, and the adjacent fuel cell 105s are connected to each other. Are connected in series. Since the lead film 115 needs to have electron conductivity and a coefficient of thermal expansion close to that of other materials constituting the cell stack 101, Ni such as Ni / YSZ and a zirconia-based electrolyte material are used. It is composed of a composite material. The lead film 115 derives the DC power generated by the plurality of fuel cell 105s connected in series by the interconnector to the vicinity of the end portion of the cell stack 101.

Next, the SOFC module and the SOFC cartridge according to the present embodiment will be described with reference to FIGS. 2 and 3. Here, FIG. 2 shows the SOFC module according to the present embodiment. Further, FIG. 3 shows a cross-sectional view of the SOFC cartridge according to the present embodiment.

As shown in FIG. 2, the SOFC module (fuel cell module) 201 includes, for example, a plurality of SOFC cartridges 203 and a pressure vessel 205 for accommodating the plurality of SOFC cartridges 203. Although FIG. 2 illustrates a cylindrical SOFC cell stack, this is not necessarily the case, and a flat cell stack may be used, for example. Further, the SOFC module 201 includes a fuel gas supply pipe 207 and a plurality of fuel gas supply branch pipes 207a, and a fuel gas discharge pipe 209 and a plurality of fuel gas discharge branch pipes 209a. Further, the SOFC module 201 includes an oxidizing gas supply pipe 211 (see FIG. 4), an oxidizing gas supply branch pipe (oxidizing gas flow pipe) 212 (see FIG. 4), and an oxidizing gas discharge pipe 213 (see FIG. 4). ) And a plurality of oxidizing gas discharge branch pipes 214 (see FIG. 4).

The fuel gas supply pipe 207 is provided outside the pressure vessel 205, is connected to a fuel gas supply unit that supplies a predetermined gas composition and a predetermined flow rate of fuel gas according to the amount of power generated by the SOFC module 201, and is connected to a plurality of fuel gas supply pipes. It is connected to the fuel gas supply branch pipe 207a. The fuel gas supply pipe 207 is for branching and guiding the fuel gas of a predetermined flow rate supplied from the fuel gas supply unit described above to a plurality of fuel gas supply branch pipes 207a. Further, the fuel gas supply branch pipe 207a is connected to the fuel gas supply pipe 207 and is also 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 pipe 207 to the plurality of SOFC cartridges 203 at a substantially equal flow rate, and substantially equalizes the power generation performance of the plurality of SOFC cartridges 203. ..

The fuel gas discharge branch pipe 209a is connected to a plurality of SOFC cartridges 203 and is also connected to the fuel gas discharge pipe 209. The fuel gas discharge branch pipe 209a guides the exhaust fuel gas discharged from the SOFC cartridge 203 to the fuel gas discharge pipe 209. Further, the fuel gas discharge pipe 209 is connected to a plurality of fuel gas discharge branch pipes 209a, and a part of the fuel gas discharge pipe 209 is arranged outside the pressure vessel 205. The fuel gas discharge pipe 209 guides the exhaust fuel gas led out from the fuel gas discharge branch pipe 209a at a substantially equal flow rate to the outside of the pressure vessel 205.

Since the pressure vessel 205 is operated at an internal pressure of 0.1 MPa to about 3 MPa and an internal temperature of atmospheric temperature to about 550 ° C., it has resistance to resistance and corrosion resistance to oxidizing agents such as oxygen contained in the oxidizing gas. The material you have is used. For example, a stainless steel material such as SUS304 is suitable.

Here, in the present embodiment, a mode in which a plurality of SOFC cartridges 203 are assembled and stored in the pressure vessel 205 will be described, but the present invention is not limited to this, and for example, the SOFC cartridge 203 is not assembled and the pressure is increased. It can also be stored in the container 205.

As shown in FIG. 3, the SOFC cartridge 203 includes a plurality of cell stacks 101, a power generation chamber 215, a fuel gas supply chamber 217, a fuel gas discharge chamber (fuel gas header) 219, an oxidizing gas supply chamber 221 and oxidation. It is provided with a sex gas discharge chamber 223. Further, the SOFC cartridge 203 includes an upper tube plate 225a, a lower tube plate 225b, an upper heat insulating body 227a, and a lower heat insulating body 227b. In the present embodiment, in the SOFC cartridge 203, the fuel gas supply chamber 217, the fuel gas discharge chamber 219, the oxidizing gas supply chamber 221 and the oxidizing gas discharge chamber 223 are arranged as shown in FIG. The structure is such that the fuel gas and the oxidizing gas flow opposite to the inside and the outside of the cell stack 101, but this is not always necessary. For example, the fuel gas and the oxidizing gas flow in parallel to the inside and the outside of the cell stack. Alternatively, the oxidizing gas may flow in a direction orthogonal to the longitudinal direction of the cell stack.

The power generation chamber 215 is a region formed between the upper heat insulating body 227a and the lower heat insulating body 227b. The power generation chamber 215 is a region in which the fuel cell 105 of the cell stack 101 is arranged, and is a region in which the fuel gas and the oxidizing gas are electrochemically reacted to generate electricity. Further, the temperature in the vicinity of the central portion of the cell stack 101 in the longitudinal direction of the power generation chamber 215 is monitored by a temperature sensor or the like, and becomes a high temperature atmosphere of about 700 ° C. to 1000 ° C. during steady operation of the SOFC module 201.

The fuel gas supply chamber 217 is an area surrounded by the upper casing 229a and the upper pipe plate 225a of the SOFC cartridge 203, and the fuel gas supply branch pipe 207a is provided by the fuel gas supply hole 231a provided in the upper part of the upper casing 229a. Is communicated with. Further, the plurality of cell stacks 101 are joined to the upper pipe plate 225a by the seal member 237a, and the fuel gas supply chamber 217 is supplied from the fuel gas supply branch pipe 207a through the fuel gas supply hole 231a. The gas is guided into the substrate tubes 103 of the plurality of cell stacks 101 at a substantially uniform flow rate to substantially equalize the power generation performance of the plurality of cell stacks 101.

The fuel gas discharge chamber 219 is an area surrounded by the lower casing 229b and the lower pipe plate 225b of the SOFC cartridge 203, and the fuel gas discharge branch pipe 209a is provided by the fuel gas discharge hole 231b provided in the lower part of the lower casing 229b. Is communicated with. Further, the plurality of cell stacks 101 are joined to the lower pipe plate 225b by the seal member 237b, and the fuel gas discharge chamber 219 passes through the inside of the base pipe 103 of the plurality of cell stacks 101 to discharge the fuel gas. The chamber 219 collects the exhaust fuel gas that passes through the inside of the base pipe 103 of the plurality of cell stacks 101 and is supplied to the fuel gas discharge chamber 219, and the fuel gas discharge branch pipe 209a passes through the fuel gas discharge hole 231b. It leads to.

Oxidizing gas having a predetermined gas composition and a predetermined flow rate is branched into an oxidizing gas supply branch pipe 212 according to the amount of power generated by the SOFC module 201, and is supplied to a plurality of SOFC cartridges 203. The oxidizing gas supply chamber 221 is an area surrounded by the lower casing 229b, the lower tube plate 225b, and the lower heat insulating body 227b of the SOFC cartridge 203. Further, an oxidizing gas supply hole 233a provided on the side surface of the lower casing 229b communicates with an oxidizing gas supply branch pipe (not shown). The oxidizing gas supply chamber 221 supplies an oxidizing gas having a predetermined flow rate supplied from an oxidizing gas supply branch pipe 212 (not shown) through the oxidizing gas supply hole 233a to an oxidizing gas supply gap (oxidizing gas) described later. It leads to the power generation chamber 215 via the supply unit) 235a.

The oxidizing gas discharge chamber 223 is an area surrounded by the upper casing 229a, the upper tube plate 225a, and the upper heat insulating body 227a of the SOFC cartridge 203. Further, the oxidizing gas discharge hole 233b provided on the side surface of the upper casing 229a communicates with the oxidizing gas discharge branch pipe 214. The oxidizing gas discharge chamber 223 oxidizes the oxidative gas supplied from the power generation chamber 215 to the oxidative gas discharge chamber 223 via the oxidative gas discharge gap (oxidizing gas discharge portion) 235b described later. It leads to a third oxidizing gas discharge branch pipe (not shown) through the gas discharge hole 233b.

In the upper casing 225a, the upper casing 229a is provided so that the upper tube plate 225a, the top plate of the upper casing 229a, and the upper heat insulating body 227a are substantially parallel to each other between the top plate of the upper casing 229a and the upper heat insulating body 227a. It is fixed to the side plate of. Further, the upper tube plate 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 plate 225a airtightly supports one end of the plurality of cell stacks 101 via one or both of the sealing member 237a and the adhesive member, and also provides a fuel gas supply chamber 217 and an oxidizing gas discharge chamber. It isolates from 223.

The lower tube plate 225b is attached to the side plate of the lower casing 229b so that the bottom plate of the lower tube plate 225b, the bottom plate of the lower casing 229b, and the lower heat insulating body 227b are substantially parallel to each other between the bottom plate of the lower casing 229b and the lower heat insulating body 227b. It is fixed. Further, the lower tube plate 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 plate 225b airtightly supports the other end of the plurality of cell stacks 101 via one or both of the sealing member 237b and the adhesive member, and also provides a fuel gas discharge chamber 219 and an oxidizing gas supply chamber. It isolates from 221.

The upper heat insulating body 227a is arranged at the lower end of the upper casing 229a so that the upper heat insulating body 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 229a. There is. Further, the upper heat insulating body 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 this hole is set to be larger than the outer diameter of the cell stack 101. The upper heat insulating body 227a includes an oxidizing gas discharge gap 235b formed between the inner surface of the hole and the outer surface of the cell stack 101 inserted through the upper heat insulating body 227a.

The upper heat insulating body 227a separates the power generation chamber 215 and the oxidizing gas discharge chamber 223, and the atmosphere around the upper pipe plate 225a becomes high in temperature, resulting in a decrease in strength and corrosion by the oxidizing agent contained in the oxidizing gas. Suppress the increase. The upper tube plate 225a and the like are made of a metal material having high temperature durability such as Inconel, but the upper tube plate 225a and the like are exposed to the high temperature in the power generation chamber 215 and the temperature difference in the upper tube plate 225a and the like becomes large. It prevents thermal deformation. Further, the upper heat insulating body 227a guides the oxidative gas that has passed through the power generation chamber 215 and exposed to high temperature to the oxidative gas discharge chamber 223 by passing through the oxidative gas discharge gap 235b.

According to the present embodiment, due to the structure of the SOFC cartridge 203 described above, the fuel gas and the oxidizing gas flow toward the inside and the outside of the cell stack 101. As a result, the oxidative gas exchanges heat with the fuel gas supplied to the power generation chamber 215 through the inside of the base tube 103, and the upper tube plate 225a and the like made of a metal material buckle and the like. It is cooled to a temperature at which it does not deform and is supplied to the oxidizing gas discharge chamber 223. Further, the fuel gas is heated by heat exchange with the oxidative gas discharged from the power generation chamber 215 and supplied to the power generation chamber 215. As a result, the fuel gas preheated and raised 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 insulating body 227b is arranged at the upper end of the lower casing 229b so that the lower heat insulating body 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 lower casing 229b. .. Further, the lower heat insulating body 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 this hole is set to be larger than the outer diameter of the cell stack 101. The lower heat insulating body 227b includes an oxidizing gas supply gap 235a formed between the inner surface of the hole and the outer surface of the cell stack 101 inserted through the lower heat insulating body 227b.

The lower heat insulating body 227b separates the power generation chamber 215 and the oxidizing gas supply chamber 221, and the atmosphere around the lower pipe plate 225b becomes high in temperature, resulting in a decrease in strength and corrosion by the oxidizing agent contained in the oxidizing gas. Suppress the increase. The lower tube plate 225b or the like is made of a metal material having high temperature durability such as Inconel, but the lower tube plate 225b or the like is exposed to a high temperature and the temperature difference in the lower tube plate 225b or the like becomes large, so that it is thermally deformed. It is something to prevent. Further, the lower heat insulating body 227b guides the oxidizing gas supplied to the oxidizing gas supply chamber 221 to the power generation chamber 215 through the oxidizing gas supply gap 235a.

According to the present embodiment, due to the structure of the SOFC cartridge 203 described above, the fuel gas and the oxidizing gas flow toward the inside and the outside of the cell stack 101. As a result, the exhaust fuel gas that has passed through the inside of the base pipe 103 and passed through the power generation chamber 215 is heat-exchanged with the oxidizing gas supplied to the power generation chamber 215, and the lower pipe plate 225b made of a metal material is exchanged. Etc. are cooled to a temperature at which deformation such as buckling does not occur and supplied to the fuel gas discharge chamber 219. Further, 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 a lead film 115 made of Ni / YSZ or the like provided in the plurality of fuel cell 105, and then the current collecting rod of the SOFC cartridge 203 (non-collective rod). The current is collected by the current collector plate (not shown) on the (shown), and is taken out to the outside of each SOFC cartridge 203. The DC power derived to the outside of the SOFC cartridge 203 by the collector rod connects the generated power of each SOFC cartridge 203 to a predetermined number of series and parallel numbers, and is led out to the outside of the SOFC module 201. It is converted into predetermined AC power by a power conversion device (inverter or the like) such as a power conditioner (not shown), and is supplied to a power supply destination (for example, a load facility or a power system). Some of the current collector rods project upward and some project downward of the SOFC cartridge 203. The collector rod projecting upward penetrates the fuel gas supply chamber 217 and the sub-module upper heat insulating material 11 described later and extends upward. The collecting rod projecting downward penetrates the fuel gas discharge chamber 219 and the sub-module lower heat insulating material 12 described later and extends downward.

The SOFC module 201 further includes a pressure vessel side heat insulating material 1. The pressure vessel side heat insulating material 1 is arranged so as to cover the inner peripheral wall of the pressure vessel 205.

Next, the details of the SOFC submodule (fuel cell submodule) 202 (see FIG. 2) in which a plurality of SOFC cartridges 203 are combined will be described with reference to FIGS. 4 to 9. Note that FIG. 4 schematically shows a vertical cross-sectional view of the SOFC module 201. Due to the illustration, a plurality of SOFC cartridges 203 (see FIG. 2) are not shown separately and are grouped together. It is shown as the SOFC submodule 202.

As shown in FIG. 4, in the SOFC submodule 202, in addition to the plurality of SOFC cartridges 203, the cartridge heat insulating material (sealing member) 2 surrounding the power generation chamber 215 and the plurality of SOFC cartridges 203 outside the cartridge heat insulating material 2 The submodule heat insulating material 3 that surrounds the whole, the plate frame-shaped side exterior plate 4 that defines the side of the SOFC submodule 202, and the entire lower end of the side exterior plate 4 in the direction of the central axis of the SOFC submodule 202. It has a lower exterior plate 5 that extends substantially horizontally toward the bottom of the SOFC submodule 202 and defines the lower part of the SOFC submodule 202, and is housed inside the pressure vessel 205.

The cartridge heat insulating material 2 is formed by laminating and joining a plurality of boards (or boards) formed of the heat insulating material. Further, the cartridge heat insulating material 2 is formed by joining the cartridge upper heat insulating material 6 to which the upper heat insulating body 227a (see FIG. 3) provided by each of the plurality of SOFC cartridges 203 is bonded and the lower heat insulating body 227b provided by each of the plurality of SOFC cartridges 203. The cartridge lower heat insulating material 7 is provided, and a plate frame-shaped cartridge side heat insulating material 8 that connects the entire side surface of the cartridge upper heat insulating material 6 and the entire side surface of the cartridge lower heat insulating material 7 is provided. The cartridge side heat insulating material 8 is composed of a plurality of heat insulating members 8a whose upper and lower end faces have a key-shaped uneven shape, and the plurality of heat insulating members 8a are fitted with the unevenness of the heat insulating members 8a adjacent to each other in the vertical direction. It has a so-called in-row structure connected to the heat insulating member 8a, and has a structure in which a continuous gap is unlikely to occur between the heat insulating members 8a, thereby suppressing the passage of oxidizing gas (see FIG. 9). The cartridge upper heat insulating material 6, the cartridge lower heat insulating material 7, and the cartridge side heat insulating material 8 are connected so as to form a box-shaped sealed space inside, and all the fuel cell cells included in the SOFC submodule 202 are inside. 105 is placed. That is, the cartridge upper heat insulating material 6, the cartridge lower heat insulating material 7, and the cartridge side heat insulating material 8 pass through the rest other than the oxidizing gas supply gap 235a and the oxidizing gas discharge gap 235b, and are connected to the inside of the pressure vessel 205. A power generation chamber 215 sealed inside is formed so as to suppress the inflow or leakage of the oxidizing gas between them. Therefore, the cartridge heat insulating material 2 surrounds only a part of the cell stack 101 in which the fuel cell 105 is provided. That is, since the fuel cell 105 is provided at the substantially central portion of the cell stack 101 in the longitudinal direction and is not provided at the end portion, the cartridge heat insulating material 2 surrounds only the substantially central portion of the cell stack 101. It will be.

The submodule heat insulating material 3 is formed by laminating and joining a plurality of boards (or boards) formed of the heat insulating material, and is arranged inside the pressure vessel 205 so as to surround the plurality of SOFC cartridges 203. .. The sub-module heat insulating material 3 has a substantially rectangular parallelepiped shape in which a space is formed inside. The sub-module heat insulating material 3 includes a sub-module upper heat insulating material 11 which corresponds to an upper surface portion of the rectangular parallelepiped, a sub-module lower heat insulating material 12 which corresponds to a lower surface portion of the rectangular parallelepiped, and a sub-module side heat insulating material 13 which corresponds to a side surface portion of the rectangular parallelepiped.

The lower surface of the sub-module upper heat insulating material 11 is fixed to the upper surface of the upper casing 229a. The sub-module side heat insulating material 13 is a plate frame-shaped member extending vertically downward from the four side ends of the sub-module upper heat insulating material 11, and is subjected to thermal expansion at, for example, the central portion or the lower end portion of the inner peripheral surface. It is fixed to the outer peripheral surface of the cartridge side heat insulating material 8 so as to avoid relative positional displacement and mutual restraint. The upper surface of the sub-module lower heat insulating material 12 is fixed to the lower surface of the lower casing 229b. The four side ends of the sub-module lower heat insulating material 12 extend to the vicinity of the lower end of the sub-module side heat insulating material 13 and are fixed to the seal plate 15 described later. That is, the sub-module lower heat insulating material 12 and the sub-module side heat insulating material 13 are connected via the sealing plate 15. As described above, the sub-module lower heat insulating material 12 and the sub-module side heat insulating material 13 are configured to form a box-shaped inner space 10 inside, and the sub-module upper heat insulating material 11 is a sub-module side heat insulating material. It is installed between the SOFC cartridge 203 and the SOFC cartridge 203 so as to allow vertical displacement due to thermal expansion.

The submodule heat insulating material 3 separates the inside of the pressure vessel 205 into an outer space 9 and an inner space 10. The outer space 9 is a space formed between the pressure vessel 205 and the submodule heat insulating material 3. The inner space 10 is a space surrounded by the sub-module heat insulating material 3, and accommodates a plurality of SOFC cartridges 203, the cartridge heat insulating material 2, and the like. That is, the inner space 10 is a space including the power generation chamber 215, and the inner space 10 and the power generation chamber 215 are separated by the cartridge heat insulating material 2.

The side exterior plate 4 is a metal plate having a thickness of about 2 mm to 5 mm, has a plate frame shape formed of a plate material having heat resistance and corrosion resistance (for example, SUS304), and has an inner peripheral surface that insulates the side of the submodule. It is fixed to and from the peripheral outer peripheral surface of the material 13. Further, the side exterior plate 4 has an opening formed at the lower end thereof, and a part of the lower end is covered with the lower exterior plate 5 described later. Further, an opening defined by the upper edge of the side exterior plate 4 is formed at the upper end of the side exterior plate 4. The lower end of the side exterior plate 4 is arranged so as to be lower than the bottom surface of the lower casing 229b.

The lower exterior plate 5 is a plate-shaped member extending from the lower end of the plate frame-shaped side exterior plate 4 substantially horizontally toward the central axis direction of the SOFC submodule 202 to the side end portion of the lower casing 229b. It is made of a metal plate (for example, SUS304) having a thickness of about 2 mm to 5 mm. The upper surface of the lower exterior plate 5 and the upper surface of the lower casing 229b are separated so as to form a space, and a seal plate 15 described later is provided in this space. Further, as shown in FIGS. 5 and 6, a through hole 16 is formed in the lower exterior plate 5, and the lower exterior plate 5 is a tubular portion (cylindrical member) extending downward so as to communicate with the through hole 16. Has 17. As shown in FIG. 5, an oxidizing gas supply branch pipe 212 is inserted through the through hole 16 and the tubular portion 17. The tubular portion 17 and the oxidizing gas supply branch pipe 212 are sealed and fixed at the lower end portion of the tubular portion 17. Further, a part of the tubular portion 17 is formed of a flexible flexible pipe 18 that allows expansion and contraction in the vertical direction, and a part of the oxidizing gas supply branch pipe 212 also allows expansion and contraction in the vertical direction. It is formed of a flexible flexible pipe 19, and allows a difference in thermal expansion due to a temperature difference between the tubular portion 17 and the oxidizing gas supply branch pipe 212.

As shown in FIG. 6, a seal plate 15 is provided between the upper surface of the lower exterior plate 5 and the lower surface of the lower casing 229b. As shown in FIGS. 7 and 8, the seal plate 15 is a frame-shaped member whose outer shape is substantially the same as the area of the bottom surface of the SOFC submodule 202, and an opening is formed in a substantially central portion thereof. The seal plate 15 includes a rectangular annular horizontal portion 21 and a vertical portion 22 extending substantially vertically upward from substantially the entire inner peripheral end of the horizontal portion 21. The lower surface of the horizontal portion 21 is welded and fixed to the upper surface of the lower exterior plate 5, and the upper end of the vertical portion 22 is welded and fixed to the lower surface of the lower casing 229b. Further, the sub-module lower heat insulating material 12 is fitted in the opening formed in the substantially central portion of the seal plate 15 over substantially the entire area. That is, the outer peripheral surface of the sub-module lower heat insulating material 12 is fixed to the inner peripheral surface of the vertical portion 22.
There is a possibility that a gap may be generated between the cartridge heat insulating material 2 and the peripheral structure such as the metal oxidizing gas supply chamber 221 due to the difference in the coefficient of thermal expansion, and the oxidizing gas may leak out. Therefore, a blanket material (an elastic heat insulating material obtained by compacting ceramic fibers) may be provided in a portion where a gap is likely to occur between them to prevent the gap from occurring.

Further, from the lower surface of the lower casing 229b, six legs 23 for erecting the SOFC cartridge 203 in the pressure vessel 205 extend downward. In the example of the present embodiment, there are six leg portions 23, and the lower surface of each leg portion 23 is fixed to the upper surface of the horizontal portion 21 of the seal plate 15. That is, each of the six leg portions 23 is placed on a pedestal (not shown) provided in the pressure vessel 205 via the horizontal portion 21 and the lower exterior plate 5, and the SOFC cartridge 203 It is erected in the SOFC submodule 202.

Next, the connection mode between the fuel gas supply branch pipe 207a and the like described above and the SOFC submodule 202 will be described.
From the fuel gas supply holes 231a formed on the upper surface of the upper casing 229a, a plurality of fuel gas supply branch pipes 207a (two in the description example of FIG. 4) penetrate the submodule upper heat insulating material 11 and extend upward. There is. The plurality of fuel gas supply branch pipes 207a extending upward are bent and merged with each other. The merged fuel gas supply branch pipe 207a is connected to the fuel gas supply pipe 207. Further, from the fuel gas discharge holes 231b formed on the lower surface of the lower casing 229b, a plurality of fuel gas discharge branch pipes 209a (two in the description example of FIG. 4) penetrate the submodule lower heat insulating material 12 and downward. It is extending. The plurality of fuel gas discharge branch pipes 209a extending downward are bent and merged with each other. The merged fuel gas discharge branch pipe 209a is connected to the fuel gas discharge pipe 209.

An oxidizing gas discharge branch pipe 214 extends from the oxidizing gas discharge hole 233b formed on the side surface of the upper casing 229a. The oxidizing gas discharge branch pipe 214 extends horizontally from the oxidizing gas discharge hole 233b to the inner peripheral surface of the submodule side heat insulating material 13, and upwards along the inner peripheral surface of the submodule side heat insulating material 13. It is bent and extends upward so as to penetrate the submodule upper heat insulating material 11. The oxidizing gas discharge branch pipe 214 extending upward is bent outward near the upper end of the submodule side heat insulating material 13 and is connected to the oxidizing gas discharge pipe 213. Further, an oxidizing gas supply branch pipe 212 extends from the oxidizing gas supply hole 233a formed on the side surface of the lower casing 229b. The oxidizing gas supply branch pipe 212 extends horizontally from the oxidizing gas supply hole 233a to the inner peripheral surface of the submodule side heat insulating material 13, and downwards along the inner peripheral surface of the submodule side heat insulating material 13. It's twisted. The oxidizing gas supply branch pipe 212 that bends and extends downward is connected to the oxidizing gas supply pipe 211.

The SOFC module 201 may be applied to a combined power generation system used in combination with a GTCC (Gas Turbine Combined Cycle) or an MGT (Micro Gas Turbine). In such a combined power generation system, the exhaust fuel gas and the oxidative gas exhausted from the SOFC module 201 are supplied to a combustor (not shown) of a gas turbine to generate a high-temperature combustion gas, and this combustion gas is produced. The rotational power generated by the adiabatic expansion in the gas turbine drives the compressor to supply the compressed compressed gas as an oxidizing gas to the oxidizing gas supply pipe 211 of the SOFC module 201. The oxidizing gas is a gas containing approximately 15% to 30% of oxygen, and air is typically preferable. However, in addition to air, a mixed gas of combustion exhaust gas and air or a mixed gas of oxygen and air is used. Gas etc. can be used.

The method of assembling the SOFC submodule 202 according to the present embodiment will be described with reference to FIG.
First, the side exterior plate 4 and the lower exterior plate 5 are connected, and the side exterior plate 4 and the lower exterior plate 5 are connected (hereinafter, simply referred to as "exterior plate" in this paragraph) at a predetermined position. Deploy. Next, a material in which the sub-module lower heat insulating material 12 and the sub-module side heat insulating material 13 are connected (hereinafter, simply referred to as “sub-module heat insulating material” in this paragraph) is fitted into the exterior plate from above, and the exterior plate is fitted. It is arranged inside the. Next, the SOFC cartridge 203 is assembled. Specifically, the cell stack 101 is arranged, the plurality of heat insulating members 8a are assembled, the cartridge side heat insulating material 8 in which the plurality of heat insulating members 8a are assembled, and the like are arranged. Next, the assembled SOFC cartridge 203 is fitted into the sub-module heat insulating material from above and arranged inside the sub-module heat insulating material. Finally, the sub-module upper heat insulating material 11 is fitted into the sub-module heat insulating material from above the SOFC cartridge 203. When disassembling the SOFC submodule 202, the reverse procedure is performed.

According to this embodiment, the following effects are exhibited.
In the present embodiment, the cartridge upper heat insulating material 6, the cartridge lower heat insulating material 7, and the cartridge side heat insulating material 8 surround the power generation chamber 215. In the power generation chamber 215, in the rest other than the oxidizing gas supply gap 235a and the oxidizing gas discharge gap 235b, the inflow of oxidizing gas and the inflow of oxidizing gas by the cartridge upper heat insulating material 6, the cartridge lower heat insulating material 7, and the cartridge side heat insulating material 8 Since the leakage is prevented, it is possible to suppress an unintended inflow and leakage of oxidizing gas between the inside of the pressure vessel 205 and the power generation chamber 215. Therefore, the natural convection circulation of the oxidizing gas that circulates from above to below inside the power generation chamber 215 and outside the power generation chamber 215 in the space inside the pressure vessel 205, which may occur in the pressure vessel 205, is generated. It can be suppressed. Therefore, it is possible to suppress heat dissipation to the outside of the pressure vessel 205 due to the natural convection circulation of the oxidizing gas, and it is possible to suppress a decrease in the power generation efficiency of the SOFC module 201.

Further, the cartridge side heat insulating material 8 is composed of a plurality of heat insulating members 8a whose upper and lower end faces have a key-shaped uneven shape. Therefore, it is possible to simplify the work of positioning and bringing the cartridge side heat insulating material 8 into close contact with each other during assembly. Further, the plurality of heat insulating members 8a have a so-called in-row structure in which the unevenness of the heat insulating members 8a adjacent to each other on the upper and lower sides is fitted so as to be fitted, and a continuous gap is unlikely to occur between the heat insulating members 8a. Since the structure suppresses the passage of the oxidizing gas, the pressure loss becomes high for the oxidizing gas flowing through the gap between the heat insulating members 8a to flow. Therefore, it is possible to suppress the inflow and leakage of the oxidizing gas from the gap between the heat insulating members 8a.

Further, since the side exterior plate 4 is provided, the oxidizing gas that tends to flow into the power generation chamber 215 from the side of the SOFC submodule 202 is first blocked by the side exterior plate 4 and is blocked by the side exterior plate 4, and the power generation chamber 215. The oxidizing gas leaking from the pressure vessel 205 into the pressure vessel 205 is finally blocked by the side exterior plate 4. Further, the oxidizing gas that tends to flow into the SOFC submodule 202 from below is first blocked by the lower exterior plate 5 or the bottom surface of the lower casing 229b. In this way, since the inflow of oxidizing gas is prevented even on the outside of the cartridge heat insulating material 2, the inflow of unintended oxidizing gas between the inside of the power generation chamber 215 and the inside of the pressure vessel 205 is more reliable. And leakage can be suppressed. Therefore, it is possible to more reliably suppress the natural convection circulation of the oxidizing gas that leaks from the inside of the power generation chamber 215 and circulates from above to below outside the power generation chamber 215 in the space inside the pressure vessel 205. Therefore, it is possible to suppress heat dissipation to the outside of the pressure vessel 205 due to the natural convection circulation of the oxidizing gas, and it is possible to suppress a decrease in the power generation efficiency of the SOFC module 201.

Further, the bottom surface of the lower casing 229b is not covered with the lower exterior plate 5. When the structure is such that the fuel gas discharge branch pipe 209a and the current collector rod penetrate the lower exterior plate 5, the fuel gas discharge branch pipe 209a and the current collector rod penetrate the lower exterior plate 5 so that the oxidizing gas does not flow into the inside. It is necessary to make each part a closed structure, which complicates the structure. In particular, the current collector rod needs to have a closed structure while ensuring insulation, which complicates the structure. In the present embodiment, the bottom surface of the lower casing 229b is not covered with the lower exterior plate 5, but the bottom surface of the lower casing 229b and the lower exterior plate 5 are connected by using the seal plate 15 and formed at a substantially central portion of the seal plate 15. Since the opening is formed, the fuel gas discharge branch pipe 209a and the current collector rod communicating with the fuel gas discharge chamber 219 can have a simple structure that does not penetrate the lower exterior plate 5.

Further, when assembling the SOFC submodule 202, the lateral positioning can be assembled with reference to the side exterior plate 4, and the vertical positioning can be assembled with reference to the lower exterior plate 5. Can be done. Therefore, the positioning work at the time of assembling can be facilitated.

Further, a seal plate 15 for connecting the upper surface of the lower exterior plate 5 and the bottom surface of the lower casing 229b is provided. As a result, as shown by the arrow in FIG. 7, even when the oxidizing gas flows in from the portion where the fuel gas discharge branch pipe 209a penetrates the submodule lower heat insulating material 12, the flowing oxidizing gas can be removed. It is blocked by the seal plate 15 and does not reach the power generation room 215. Therefore, even if a space is formed between the upper surface of the lower exterior plate 5 and the bottom surface of the lower casing 229b and the legs 23 are provided, it is possible to prevent the oxidizing gas from flowing into the SOFC submodule 202. can do.

Further, since the upper end of the side exterior plate 4 is not provided with a lid material that covers the upper part of the SOFC submodule 202 and is connected to and fixed to the upper end of the side exterior plate 4, the SOFC submodule 202 is configured. Even when the member thermally expands due to a high temperature, the thermal expansion can be allowed upward.

Further, a through hole 16 is formed in the lower exterior plate 5, and a tubular portion 17 communicating with the through hole 16 is provided. As a result, the piping that needs to be disposed toward the lower side of the lower casing 229b, that is, the oxidizing gas supply branch pipe 212 extending downward from the side of the lower casing 229b, is inserted into the through hole 16 and the inside of the tubular portion 17. By being inserted, the oxidizing gas supply branch pipe 212 can communicate with the oxidizing gas supply pipe 211 arranged outside the SOFC submodule 202. Further, since the inside of the tubular portion 17 is inserted, the insertion portion has a double pipe structure and one end is sealed and fixed, so that the oxidizing gas supply branch pipe 212 penetrates the lower exterior plate 5. Even so, it is possible to prevent the oxidizing gas from flowing into the SOFC submodule 202 from the penetrating portion and leaking into the space inside the pressure vessel 205.

Further, a part of the tubular portion 17 is formed of a flexible tube 18 which is flexible and allows expansion and contraction in the vertical direction. As a result, even if the tubular portion 17 or the oxidizing gas supply branch pipe 212 is exposed to a high temperature and a thermal expansion difference occurs due to the temperature difference between the tubular portion 17 and the oxidizing gas supply branch pipe 212, the flexible pipe 18 Absorbs expansion and contraction in the vertical direction, so that the fixed portion between the tubular portion 17 and the oxidizing gas supply branch pipe 212 is not constrained, so that the stress generated in the pipe can be reduced. Further, a part of the oxidizing gas supply branch pipe 212 is also formed of a flexible pipe 19 having flexibility. Therefore, since the expansion and contraction in the vertical direction can be absorbed even on the oxidizing gas supply branch pipe 212 side, the fixed portion between the tubular portion 17 and the oxidizing gas supply branch pipe 212 is not restrained, so that the stress generated in the pipe can be reduced. It can be further reduced.

Further, since the oxidizing gas supply branch pipe 212 and the oxidizing gas discharge branch pipe 214 extend in the vertical direction inside the side exterior plate 4 and the sub-module side heat insulating material 13, the oxidizing gas supply branch is extended. The pipe 212 and the oxidizing gas discharge branch pipe 214 do not interfere with the side exterior plate 4 and the submodule side heat insulating material 13. As a result, it is not necessary to form a structure for penetrating the oxidizing gas supply branch pipe 212 and the oxidizing gas discharge branch pipe 214 in the side exterior plate 4, so that the configuration can be simplified.

Further, since the structure is such that the oxidizing gas supply branch pipe 212 and the oxidizing gas discharge branch pipe 214 do not interfere with the side exterior plate 4 and the submodule side heat insulating material 13, the SOFC submodule 202 is assembled. At that time, the side exterior plate 4, the sub-module side heat insulating material 13, and the SOFC cartridge 203 can be assembled separately. After separately assembling the side exterior plate 4 and the sub-module side heat insulating material 13 and the SOFC cartridge 203, the SOFC cartridge 203 is attached to the side exterior plate 4 and the sub-module side heat insulating material 13 from above. By fitting, the SOFC submodule 202 can be easily assembled. Further, when disassembling, the SOFC submodule 202 can be easily disassembled by pulling out the SOFC cartridge 203 from the side exterior plate 4 and the submodule side heat insulating material 13 from above. Further, since the oxidizing gas supply branch pipe 212 and the oxidizing gas discharge branch pipe 214 do not penetrate the submodule side heat insulating material 13, the submodule side heat insulating material 13 is damaged when the SOFC submodule 202 is disassembled. It can be disassembled without causing it.

The present invention is not limited to the invention according to each of the above embodiments, and can be appropriately modified without departing from the gist thereof. For example, in the above embodiment, the lower exterior plate 5 covers only a part of the lower part of the SOFC submodule 202, but the lower exterior plate may cover the entire lower part of the SOFC submodule 202. That is, the lower exterior plate may be provided so as to cover all the openings formed at the lower ends of the side exterior plate 4 formed in a frame shape.
With such a configuration, the oxidizing gas that tends to flow into the SOFC submodule 202 from the side is blocked by the side exterior plate 4, and the entire lower portion of the SOFC submodule 202 is covered with the lower exterior plate 5. Therefore, the oxidizing gas that tends to flow into the SOFC submodule 202 from below is surely blocked by the lower exterior plate 5. Therefore, it is possible to more reliably suppress the inflow and outflow of unintended oxidizing gas between the inside of the pressure vessel 205 and the power generation chamber 215.

Further, in the above embodiment, the lower exterior plate 5 and the lower casing 229b are fixed via the seal plate 15, but the lower exterior plate 5 and the lower casing 229b are arranged so as not to be separated from each other so that the lower exterior plate 5 and the lower casing 229b are not separated from each other. And the lower casing 229b may be directly fixed.

2 Cartridge insulation (sealing member)
3 Submodule insulation 4 Side exterior plate 5 Lower exterior plate 6 Cartridge upper insulation 7 Cartridge lower insulation 8 Cartridge side insulation 11 Submodule upper insulation 12 Submodule lower insulation 13 Submodule side insulation 15 Seal plate 16 Through hole 17 Cylindrical part (cylindrical member)
23 Leg 101 Cell stack 103 Base tube 105 Fuel cell cell 201 SOFC module (fuel cell module)
202 SOFC submodule (fuel cell submodule)
203 SOFC cartridge 205 Pressure vessel 207 Fuel gas supply pipe 207a Fuel gas supply branch pipe 209 Fuel gas discharge pipe 209a Fuel gas discharge branch pipe 211 Oxidizing gas supply pipe 212 Oxidizing gas supply branch pipe (oxidizing gas flow pipe)
213 Oxidizing gas discharge pipe 214 Oxidizing gas discharge branch pipe 215 Power generation room 217 Fuel gas supply room 219 Fuel gas discharge room (fuel gas header)
221 Oxidizing gas supply chamber 223 Oxidizing gas discharge chamber 227a Upper heat insulating body 227b Lower heat insulating body 229a Upper casing 229b Lower casing 235a Oxidizing gas supply gap (oxidizing gas supply part)
235b Oxidizing gas discharge gap (oxidizing gas discharge part)

Claims (14)

A fuel cell submodule housed in a pressure vessel
With at least one cell stack with fuel cell cells that generate electricity by supplying fuel gas and oxidizing gas,
A side exterior plate arranged so as to surround the cell stack and defining the side,
A lower exterior plate that connects to the lower end of the side exterior plate and closes an opening formed at the lower end of the side exterior plate is provided.
It said lateral outer plate, the upper end, the fuel cell submodule that have a opening defined by the upper edge of the side outer plate. A fuel cell submodule housed in a pressure vessel
With at least one cell stack with fuel cell cells that generate electricity by supplying fuel gas and oxidizing gas,
A side exterior plate arranged so as to surround the cell stack and defining the side,
A fuel gas header in which a plurality of the cell stacks are connected to supply the fuel gas to the plurality of cell stacks or discharge the fuel gas from the plurality of cell stacks.
A fuel cell submodule comprising a lower exterior plate having one end connected to the lower end of the side exterior plate and the other end connected to the side end of the fuel gas header. The fuel cell submodule according to claim 2, wherein the side exterior plate has an opening defined by the upper edge of the side exterior plate at the upper end. A through hole is formed in the lower exterior plate.
The fuel cell submodule according to any one of claims 1 to 3, wherein the lower exterior plate includes a tubular member that communicates with the through hole and extends vertically downward. A pipe for inserting the inside of the tubular member is provided.
A part of the tubular member is formed of a flexible tube having flexibility.
The fuel cell submodule according to claim 4, wherein the portion formed by the flexible pipe is located vertically above the portion for sealing and fixing the tubular member and the pipe. A fuel gas header in which a plurality of the cell stacks are connected to supply the fuel gas to the plurality of cell stacks or discharge the fuel gas from the plurality of cell stacks.
The fuel cell submodule according to claim 1, wherein one end is connected to the lower end of the side exterior plate, and the other end is connected to the side end of the fuel gas header. The upper surface of the lower exterior plate in the vertical direction and the bottom surface of the fuel gas header are separated in the vertical vertical direction.
The fuel cell submodule according to claim 2 or 6, wherein the upper surface of the lower exterior plate in the vertical direction and the bottom surface of the fuel gas header are connected via a seal plate extending in the vertical vertical direction. A sealing member that encloses at least a part of the cell stack.
Each of the plurality of cell stacks includes a central portion in which the fuel cell is provided and an end portion in which the fuel cell is not provided.
A part of the cell stack surrounded by the sealing member is the central portion where the fuel cell is provided.
The sealing member includes an oxidizing gas supply unit that supplies the oxidizing gas around a plurality of cell stacks inside the sealing member, and an oxidizing gas discharging unit that discharges the oxidizing gas from the inside. The fuel according to claim 1, wherein the remaining portion other than the oxidizing gas supply section and the oxidizing gas discharging section suppresses the inflow of the oxidizing gas into the inside and the leakage of the oxidizing gas from the inside. Battery submodule. An oxidizing gas flow pipe that communicates with the oxidizing gas supply unit or the oxidizing gas discharge unit is provided.
The fuel cell submodule according to claim 8, wherein the oxidizing gas flow pipe extends vertically in the vertical direction inside the side exterior plate. A fuel cell module comprising a pressure vessel and the fuel cell submodule according to any one of claims 1 to 9, which is housed in the pressure vessel. The fuel cell module according to claim 10 and
It is provided with a gas turbine that generates rotational power using the exhaust fuel gas and the oxidative gas exhausted from the fuel cell module.
The oxidizing gas compressed by the rotational power is supplied to the fuel cell module.
The plurality of cell stacks are combined power generation systems that generate power using the fuel gas and the oxidizing gas. With at least one cell stack with fuel cell cells that generate electricity by supplying fuel gas and oxidizing gas,
A side exterior plate that is arranged so as to surround the cell stack , defines the sides, and has an opening defined by an upper edge at the upper end, and is connected to the lower end of the side exterior plate to be connected to the side. A method of assembling a fuel cell submodule including a lower exterior plate that closes an opening formed at the lower end of the exterior plate.
A connection step for connecting the side exterior plate and the lower exterior plate, and
A method for assembling a submodule, comprising a cell stack insertion step of inserting the cell stack vertically above the side exterior plate connected in the connection step. The method for assembling a submodule according to claim 12, further comprising a sealing member disposing step of disposing the sealing member so as to surround the cell stack. The method for assembling a submodule according to claim 12 or 13, further comprising a submodule heat insulating material fitting step of fitting the submodule heat insulating material into the side outer plate and the lower outer plate.

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