JP6017659B1 - Fuel cell system - Google Patents

Abstract

A fuel cell system capable of improving the performance of a fuel cell stack when reusing anode off gas is obtained. A fuel cell system 10A includes a separation unit 20 that separates at least one of carbon dioxide and water vapor from an anode off gas G3. In the first heat exchange unit 30, heat exchange is performed between the anode offgas G <b> 3 and the air A that flows into the separation unit 20, and the anode offgas G <b> 3 and the air A after the heat exchange flow into the separation unit 20. The heat exchange between the anode off gas G3 and the air A is controlled so as to have an appropriate temperature T0 at which the function of the separation membrane 28 in the separation unit 20 is exhibited. [Selection] Figure 1

Description

  The present invention relates to a fuel cell system.

In the fuel cell system, as a configuration for improving the energy utilization efficiency, a single fuel cell stack is used, and a circulation type in which unreacted fuel gas discharged from the fuel cell stack is circulated and reused, or a fuel There is known a multi-stage system in which a plurality of battery stacks are provided and an unreacted fuel gas in a used fuel gas discharged from a preceding fuel cell stack is reused in a subsequent fuel cell stack. In any configuration, if the water vapor and carbon dioxide (CO ₂ ) contained in the spent fuel gas can be removed, the concentration of hydrogen and carbon monoxide contributing to the reaction increases, so that the fuel gas to be reused is supplied. The fuel cell stack performance is expected to improve.

  In relation to the above, Patent Document 1 discloses that in a fuel treatment process of a solid oxide fuel cell (SOFC), water vapor is separated from a spent fuel gas discharged from the fuel cell stack by a separation membrane. A technique for removing the gas and reusing it as a regenerated fuel gas is disclosed. Patent Document 1 shows an example in which air is introduced to the permeation side to reduce the partial pressure of water vapor on the permeation side, and this facilitates the permeation of water vapor through the separation membrane.

US Patent Publication 2013/0108936

  When a separation membrane is used to remove specific substances such as carbon dioxide and water vapor from spent fuel (anode offgas) at the fuel electrode in a fuel cell, further ingenuity is required.

  The present invention has been made in consideration of the above facts, and can effectively improve the performance of the fuel cell stack by effectively exerting the function of the separation membrane used when generating the regeneration gas from the anode off-gas. The object is to obtain a battery system.

  According to a first aspect of the present invention, there is provided a fuel cell system that generates electric power using fuel gas supplied to a fuel electrode and air supplied to an air electrode, and discharges anode off-gas from the fuel electrode and cathode off-gas from the air electrode. A fuel cell from which the anode off gas flows, and a permeation section partitioned from the inflow portion by a separation membrane that separates at least one of carbon dioxide and water vapor from the anode off gas. A separation unit that sends out a regenerated fuel gas in which the concentration of at least one of carbon dioxide and water vapor is reduced from the anode off gas, an air supply unit that supplies air to the permeation unit as a sweep gas, and an upstream side of the separation unit And a first heat exchange unit that exchanges heat between the anode off gas and the air from the air supply unit.

The fuel cell system according to claim 1 has a separation part. The separation unit includes a separation membrane that separates at least one of carbon dioxide and water vapor from the anode off-gas, and has an inflow portion and a permeation portion that are separated from each other by the separation membrane. Air as the sweep gas flows into the permeation section. Thereby, compared with the case where there is no passage of air, the partial pressure of at least one of the carbon dioxide and water vapor | steam in a permeation | transmission part is reduced. On the other hand, the anode off gas flows into the inflow portion. At least one of carbon dioxide and water vapor contained in the anode off-gas flowing into the inflow portion permeates the separation membrane and flows into the permeation portion. As a result, the concentration of at least one of carbon dioxide and water vapor in the anode off-gas is reduced and sent out from the inflow portion as regenerated fuel gas. The regenerated fuel gas can be used again for power generation of the fuel cell.

By the way, in order for the separation membrane to properly exhibit the separation function in the separation part, it is required that the separation part has an appropriate temperature. In the fuel cell system of the present invention, in the first heat exchange unit, heat exchange is performed between the anode offgas and the air flowing into the separation unit, and the anode offgas and air after the heat exchange are performed between the inflow unit and the permeation unit of the separation unit. To each. Therefore, for example, by adjusting the air flow rate and temperature, it is possible to easily set an appropriate temperature for both the anode offgas and the air flowing into the separation unit. Thus, by maintaining the separation part at an appropriate temperature and exhibiting the performance of the separation membrane, at least one of carbon dioxide and water vapor can be largely separated from the anode off-gas. As a result, the fuel cell stack that reuses the anode off-gas can efficiently generate power, and the performance of the fuel cell system can be improved.

The fuel cell system according to a second aspect of the invention is characterized in that the first heat exchanging unit performs heat exchange between the anode off gas and air from the air supply unit in a co-current type.

In the fuel cell system according to claim 2, since the anode off gas and the air from the air supply unit are heat-exchanged in a parallel flow type (parallel flow type) in the first heat exchange unit, the anode off gas sent to the separation unit And the air temperature can be set to the same temperature relatively easily.

A fuel cell system according to a third aspect of the present invention is provided between the air supply unit and the first heat exchange unit, and raises the temperature of air from the air supply unit. And a control unit that controls the temperature of the air that flows out of the air temperature raising unit in accordance with the temperature of the separation unit.

In the fuel cell system according to claim 3, the air flowing into the first heat exchange unit is heated by the air temperature raising unit according to the temperature of the separation unit. Therefore, the adjustment range of the flow rate of the air flowing into the first heat exchange unit can be reduced, and the separation unit can be maintained at an appropriate temperature. Thereby, the air flowing into the permeation part can be secured, and the partial pressure of at least one of carbon dioxide and water vapor in the permeation part can be lowered.

The fuel cell system according to claim 4 is characterized in that the flow rate of air flowing from the air supply unit to the first heat exchange unit is constant.

According to the fuel cell system of the fourth aspect, the separation unit can be brought to an appropriate temperature only by adjusting the temperature of the air in the air heating unit.

A fuel cell system according to a fifth aspect of the present invention includes a control unit that controls a flow rate of air flowing into the first heat exchange unit according to a temperature of the separation unit.

In the fuel cell system according to the fifth aspect, the flow rate of the air flowing into the first heat exchange unit is controlled according to the temperature of the separation unit. Therefore, the temperature of the separation unit can be easily adjusted to an appropriate temperature simply by adjusting the air flow rate.

The fuel cell system according to a sixth aspect of the present invention further includes an oxidizing gas introduction path for introducing the gas discharged from the permeation portion into the air electrode.

According to the fuel cell system of the sixth aspect, since the air after being used as the sweep gas is introduced into the air electrode, the introduction of air into the air electrode and the introduction of air into the first heat exchange unit are the same. The air supply unit (such as a blower) can be used, and the fuel cell system can be simplified.

  A fuel cell system according to a seventh aspect of the invention includes a combustor that combusts a combustible gas, and the gas discharged from the permeation unit is directly or indirectly introduced into the combustor.

According to the fuel cell system of the seventh aspect, the combustible gas such as hydrogen contained in the gas after being used as the sweep gas is introduced into the combustor and used for combustion. Thereby, the combustible gas in the gas after being used as sweep gas can be processed appropriately.

According to an eighth aspect of the present invention, in the fuel cell system according to the eighth aspect, the fuel cell includes a first fuel cell that sends an anode off gas to the inflow portion of the separation portion, and the regenerated fuel gas is supplied to the fuel electrode as the fuel gas. A second fuel cell.

  According to the fuel cell system of the eighth aspect of the present invention, the regenerated fuel gas in which the concentration of at least one of carbon dioxide and water vapor is reduced in the separation part of the anode off-gas discharged from the fuel cell is the fuel electrode of the second fuel cell. To be used. Thereby, a multistage fuel cell system can be realized.

A fuel cell system according to an invention of claim 9 is a second heat exchange unit that exchanges heat between the anode off-gas flowing upstream from the first heat exchange unit and the regenerated fuel gas, Is further provided.

According to the fuel cell system of the ninth aspect, the temperature of the anode off-gas is lowered in the second heat exchange section upstream of the first heat exchange section, so that the temperature adjustment range in the first heat exchange section is reduced. be able to. Further, since the temperature of the regenerated fuel gas after passing through the separation unit is raised in the second heat exchange unit, the temperature becomes close to a temperature suitable for reuse, and the power generation efficiency and thermal efficiency of the entire system can be improved. .

  The fuel cell system according to the present invention can improve the performance of the fuel cell stack when reusing the anode off gas.

1 is a schematic configuration diagram of a fuel cell system according to a first embodiment. It is a schematic block diagram of the fuel cell system which concerns on 2nd Embodiment. It is a schematic block diagram of the fuel cell system which concerns on 3rd Embodiment. It is a schematic block diagram of the fuel cell system which concerns on 4th Embodiment. It is a schematic block diagram of the fuel cell system which concerns on 5th Embodiment. It is a schematic block diagram of the fuel cell system which concerns on 6th Embodiment. It is a schematic block diagram of the fuel cell system which concerns on 7th Embodiment. It is a schematic block diagram of the fuel cell system which concerns on 8th Embodiment. It is a schematic block diagram of the fuel cell system which concerns on 9th Embodiment.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 shows a fuel cell system 10A according to the first embodiment of the present invention. The fuel cell system 10A includes, as main components, a vaporizer 12, a reformer 14, a first fuel cell stack 16, a second fuel cell stack 18, an air supply unit 46, a separation unit 20, a first heat exchange unit 30, A second heat exchange unit 32, a third heat exchange unit 34, a fourth heat exchange unit 36, a combustor 40, a tank 42, and a control unit 44 are provided.

  One end of the source gas pipe P1 is connected to the vaporizer 12, and the other end of the source gas pipe P1 is connected to a gas source (not shown). From the gas source, methane is sent to the vaporizer 12 by the blower B. A water supply pipe P2 from a tank 42 for storing water is connected to an intermediate portion of the source gas pipe P1. Water (liquid phase) is sent from the tank 42 to the vaporizer 12 by the pump P. In the vaporizer 12, water is vaporized. For the vaporization, the heat of the combustor 40 described later is used. In this embodiment, methane is used as the raw material gas, but it is not particularly limited as long as it can be reformed, and a hydrocarbon fuel can be used. Examples of the hydrocarbon fuel include natural gas, LP gas (liquefied petroleum gas), coal reformed gas, lower hydrocarbon gas, and the like. Examples of the lower hydrocarbon gas include lower hydrocarbons having 4 or less carbon atoms such as methane, ethane, ethylene, propane, and butane, and methane used in the present embodiment is preferable. The hydrocarbon fuel may be a mixture of the above-described lower hydrocarbon gas, and the above-described lower hydrocarbon gas may be a gas such as natural gas, city gas, or LP gas.

  Methane and water vapor are sent from the vaporizer 12 to the reformer 14 via the pipe P3. The reformer 14 is adjacent to the combustor 40, the first fuel cell stack 16, and the second fuel cell stack 18, and is heated by exchanging heat with them.

  In the reformer 14, methane is reformed to generate a fuel gas G1 containing hydrogen and having a temperature of about 600 ° C. The reformer 14 is connected to the anode (fuel electrode) 16 </ b> A of the first fuel cell stack 16. The fuel gas G1 generated by the reformer 14 is supplied to the anode 16A of the first fuel cell stack 16 via the fuel gas pipe P4.

  The first fuel cell stack 16 is a solid oxide fuel cell stack, and has a plurality of stacked fuel cells. The first fuel cell stack 16 is an example of a fuel cell (first fuel cell) in the present invention. In the present embodiment, the operating temperature is about 650 ° C. Each fuel cell has an electrolyte layer, and an anode 16A and a cathode (air electrode) 16B that are respectively laminated on the front and back surfaces of the electrolyte layer. In FIG. 1, individual anodes and cathodes of a plurality of fuel cells are collectively shown as “anode 16A” and “cathode 16B”, respectively.

  The basic configuration of the second fuel cell stack 18 is the same as that of the first fuel cell stack 16, and has an anode 18A corresponding to the anode 16A and a cathode 18B corresponding to the cathode 16B.

An oxidizing gas G5 (air) is supplied to the cathode 16B of the first fuel cell stack 16 via an oxidizing gas pipe P5 described later. In the cathode 16B, as shown in the following formula (1), oxygen and electrons in the oxidizing gas react to generate oxygen ions. The generated oxygen ions reach the anode 16A of the first fuel cell stack 16 through the electrolyte layer.

(Air electrode reaction)
1 / 2O ₂ + 2e ⁻ → O ²⁻ (1)

The cathode 16B is connected to a cathode offgas pipe P6 that guides the cathode offgas G2 discharged from the cathode 16B to the cathode 18B of the second fuel cell stack 18.

  On the other hand, in the anode 16A of the first fuel cell stack 16, as shown in the following formulas (2) and (3), oxygen ions that have passed through the electrolyte layer react with hydrogen and carbon monoxide in the fuel gas, Water (water vapor), carbon dioxide and electrons are generated. Electrons generated at the anode 16A move from the anode 16A through the external circuit to the cathode 16B, and are thus generated in each fuel cell. Each fuel cell generates heat during power generation.

(Fuel electrode reaction)
H ₂ + O ²⁻ → H ₂ O + 2e ⁻ (2)
CO + O ²⁻ → CO ₂ + 2e ⁻ (3)

  One end of an anode offgas pipe P7 is connected to the anode 16A of the first fuel cell stack 16, and the anode offgas G3 is discharged from the anode 16A to the anode offgas pipe P7. The anode off gas G3 contains unreacted hydrogen, unreacted carbon monoxide, carbon dioxide, water vapor, and the like.

The fuel cell of the present invention is not limited to a solid oxide fuel cell (SOFC), and other fuel cells in which at least one of carbon dioxide and hydrogen is contained in the anode off-gas, For example, a molten carbonate fuel cell (MCFC) may be used.

The other end of the anode off-gas pipe P7 is connected to the separation unit 20 via a second heat exchange unit 32 and a first heat exchange unit 30 described later. The separation unit 20 separates carbon dioxide and water vapor from the anode off gas G3 by a separation membrane 28 described later. The separation unit 20 includes an inflow portion 24 and a transmission portion 26. The inflow part 24 and the permeation part 26 are partitioned by a separation membrane 28.

The other end of the air supply pipe P8 is connected to the transmission part 26 of the separation part 20. The air supply unit 46 includes a blower, and one end of an air supply pipe P8 is connected to the air supply unit 46. Normal temperature air A is sent from the air supply unit 46, and air A as a sweep gas is supplied from the air supply unit 46 through the air supply pipe P <b> 8 to the transmission unit 26. The air supply unit 46 is connected to a control unit 44 described later.

  Here, the separation membrane 28 will be described. In the present embodiment, the separation membrane 28 has a function of transmitting both carbon dioxide and water vapor. In addition, in this embodiment, what has a function which permeate | transmits both a carbon dioxide and water vapor | steam is used, However, You may have a function which permeate | transmits at least one of a carbon dioxide and water vapor | steam. Although it will not specifically limit if it has a function which permeate | transmits both a carbon dioxide and water vapor | steam, For example, an organic polymer film | membrane, an inorganic material film | membrane, an organic polymer-inorganic material composite film | membrane, a liquid film etc. are mentioned. The separation membrane is more preferably a glassy polymer membrane, a rubbery polymer membrane, an ion exchange resin membrane, an alumina membrane, a silica membrane, a carbon membrane, a zeolite membrane, a ceramic membrane, an amine aqueous solution membrane or an ionic liquid membrane. preferable.

  Examples of the separation membrane include organic polymer membranes such as glassy polymer membranes, rubbery polymer membranes, and ion exchange resin membranes. Materials for the organic polymer film include polyolefin resins such as polyethylene, polypropylene, polybutene, and polymethylpentene, fluorine resins such as polytetrafluoroethylene, polyvinyl fluoride, and polyvinylidene fluoride, polystyrene, cellulose acetate, polyurethane, and polyacrylonitrile. And various organic materials such as polysulfone, polyethersulfone, polyphenylene sulfide, polyimide, polyamide, polyetherimide, polypyrrole, polyphenylene oxide, polyaniline, polyvinyl alcohol, polyacrylic acid, and polyethylene glycol. The organic polymer film may be a film composed of one kind of organic material or a film composed of two or more kinds of organic materials.

  In addition, as the separation membrane, for example, water-absorbing organic polymer such as polyvinyl alcohol, polyacrylic acid, polyvinyl alcohol-polyacrylate copolymer, polyethylene glycol, etc., carbon dioxide and water-soluble It may be an organic polymer film containing a carbon dioxide carrier exhibiting properties.

  As the carbon dioxide carrier, inorganic materials and organic materials are used. For example, inorganic materials include alkali metal salts (preferably alkali metal carbonates), ammonia, ammonium salts, and the like. Examples include amines, amine salts, and polyamines. The carbon dioxide carrier may be contained in an inorganic material film, an organic polymer-inorganic material composite film, a liquid film, or the like.

  Examples of the separation membrane include inorganic material membranes such as an alumina membrane, a silica membrane, a carbon membrane, a zeolite membrane, and a ceramic membrane. Among these, a zeolite membrane is preferable. Examples of the zeolite include A type, Y type, T type, ZSM-5 type, ZSM-35 type, and mordenite type. The inorganic material film may be a film composed of one kind of inorganic material or a film composed of two or more kinds of inorganic materials.

  The separation membrane may be an organic polymer-inorganic material composite membrane. The organic polymer-inorganic material composite film is not particularly limited as long as it is a film composed of an organic material and an inorganic material. For example, at least one organic material selected from the above-described organic materials and the above-described inorganic material A composite film composed of at least one inorganic material selected from the above is preferable.

  Examples of the separation membrane include liquid membranes such as an aqueous amine solution and an ionic liquid. These liquid films may be obtained by impregnating the above-described organic polymer film, inorganic material film, or organic polymer-inorganic material composite film with an aqueous amine solution or an ionic liquid.

  When an amine aqueous solution membrane is used as the separation membrane, carbon dioxide in the off-gas is chemically adsorbed on the amine aqueous solution membrane and then heated to separate the carbon dioxide. Moving. Examples of the aqueous amine solution include amino alcohols such as monoethanolamine.

  When an ionic liquid membrane is used as the separation membrane, carbon dioxide in the off-gas is adsorbed on the ionic liquid membrane, and the adsorbed carbon dioxide is separated from the ionic liquid membrane, so that carbon dioxide is formed on the permeate side of the ionic liquid membrane. Moving. Here, the ionic liquid is a salt having a relatively low melting point of 150 ° C. or lower. For example, a cation such as imidazolium ion or pyridinium ion, trifluoromethanesulfonate ion, tetrafluoroborate ion, hexafluoro And anions such as phosphate ions.

  The thickness of the separation membrane is not particularly limited, but from the viewpoint of mechanical strength, it is usually preferably in the range of 10 μm to 3000 μm, more preferably in the range of 10 μm to 500 μm, and still more preferably in the range of 15 μm to 150 μm. is there.

  The separation membrane may be supported by a porous support. Examples of the material for the support include paper, cellulose, polyester, polyolefin, polyamide, polyimide, polysulfone, polycarbonate, metal, glass, and ceramic.

  Moreover, as a separation membrane, the suitable temperature T0 at the time of use is higher than the dew point in the fuel cell system 10A from the viewpoint of exhibiting the function of separating carbon dioxide and water vapor and maintaining the durability. A temperature lower than the temperature of the anode off-gas G3 immediately after being discharged from the anode 16A of the stack 16 is preferably used. For example, if the dew point is 80 ° C. and the maximum use temperature considering the durability of the separation membrane is 130 ° C., an appropriate temperature T0 described later is set between 80 ° C. and 130 ° C.

As a separation membrane for separating carbon dioxide and water vapor, for example, a membrane described in “Zi Tong et al.,“ Water vapor and CO ₂ transport through amine-containing facilitated transport membranes ”, Reactive & Functional Polymers (2014) is used. May be.

  The anode off gas G3 is separated from at least one of carbon dioxide and water vapor by the separation unit 20 to reduce the concentration of carbon dioxide and water vapor, and is regenerated fuel gas G4 and is sent out from the permeation unit 26. The regenerated fuel gas pipe P9 is connected to the anode 18A of the second fuel cell stack 18, and the regenerated fuel gas G4 is supplied to the anode 18A of the second fuel cell stack 18 via the regenerated fuel gas pipe P9.

  On the other hand, in the permeation unit 26 of the separation unit 20, the air A supplied from the air supply pipe P8 flows into the permeation unit 26 as a sweep gas. As a result, the partial pressures of carbon dioxide and water vapor in the permeation section 26 are reduced, and the carbon dioxide and water vapor are easily transferred to the permeation section 26 through the separation membrane 28 from the inflow section 24. The air A is sent out from the permeation unit 26 as a permeation unit exhaust gas together with carbon dioxide, water vapor, and other gas in the anode off-gas G3 that has passed through the separation membrane 28. The sent permeate portion exhaust gas is supplied to the cathode 16B as the oxidizing gas G5 containing oxygen through the oxidizing gas pipe P5.

  The anode 18A and the cathode 18B of the second fuel cell stack 18 generate power by the same reaction as that of the first fuel cell stack 16. The used gas discharged from the anode 18A and the cathode 18B is sent to the combustor 40 through the pipe P11 and the cathode off combustion introduction pipe P12, and is used for incineration in the combustor 40. In the fuel cell system 10A of the present embodiment, the anode offgas G3 that is the fuel used in the first fuel cell stack 16 is regenerated and reused as the fuel gas in the second fuel cell stack 18. It is a system.

  From the combustor 40, combustion exhaust gas G6 is sent out. The combustion exhaust gas G6 flows through the combustion exhaust pipe P10, and flows into the tank 42 through the third heat exchange unit 34, the fourth heat exchange unit 36, and the vaporizer 12.

  Next, heat exchange in the fuel cell system 10A will be described. The fuel cell system 10 </ b> A includes a first heat exchange unit 30, a second heat exchange unit 32, a third heat exchange unit 34, and a fourth heat exchange unit 36.

  The first heat exchanging unit 30 is downstream of the anode 16A of the first fuel cell stack 16 and upstream of the separation unit 20 (inflow portion 24) (for the anode offgas pipe P7) and downstream of the air supply unit 46. It is provided on the upstream side (about the air supply pipe P8) of the separation unit 20 (permeation unit 26). In the first heat exchange unit 30, heat exchange is performed between the anode offgas G3 flowing through the anode offgas pipe P7 and the air A flowing through the air supply pipe P8. The heat exchange is preferably performed in parallel flow. By performing heat exchange in parallel flow, the temperatures of the anode offgas G3 and the air A sent to the separation unit 20 can be made relatively easily the same. Note that the anode off-gas G3 has a temperature lower than that at the time of delivery from the anode 16 due to heat exchange in the second heat exchange unit 32 described later after being delivered from the anode 16A.

  Here, at a temperature suitable for separating at least one of carbon dioxide and water vapor from the anode offgas G by the separation membrane 28, and at a temperature at which the durability of the separation membrane 28 can be maintained, and an appropriate temperature T0 higher than the dew point. Then, it is preferable that the air A and anode off gas G3 which flow into the separation part 20 from the 1st heat exchange part 30 are the temperature close | similar to the suitable temperature T0. Therefore, the control unit 44 controls the flow rate of the air A sent from the air supply unit 46 so that the air A and the anode offgas G3 flowing into the separation unit 20 from the first heat exchange unit 30 approach the appropriate temperature T0. . The appropriate temperature T0 is appropriately set depending on the material of the separation membrane 28 and the like. As described above, for example, if the dew point is 80 ° C. and the maximum use temperature considering the durability of the separation membrane 28 is 130 ° C., the appropriate temperature T 0 is set between 80 ° C. and 130 ° C.

  The separation unit 20 is provided with a temperature sensor SS that measures the temperature T of the separation unit 20. The control unit 44 controls the flow rate of the air A sent from the air supply unit 46 based on the temperature of the separation unit 20 measured by the temperature sensor SS. Specifically, when the temperature T is lower than the appropriate temperature T0, the flow rate of the air A sent from the air supply unit 46 is decreased, and when the temperature T is higher than the appropriate temperature T0, the flow is sent from the air supply unit 46. Increase the flow rate of air A. During operation of the fuel cell system 10A, the control unit 44 feedback-controls the flow rate of the air A sent from the air supply unit 46 based on the temperature T at all times or intermittently, so that the temperature of the separation unit 20 is adjusted to an appropriate temperature T0. Alternatively, it can be maintained at a temperature close to the appropriate temperature T0. The temperature T of the separation unit 20 may be the temperature inside the separation unit 20 or may be the temperature of the other part of the separation unit 20 where the separation membrane 28 is affected.

  The second heat exchange section 32 is downstream of the anode 16A of the first fuel cell stack 16 and upstream of the first heat exchange section 30 (with respect to the anode offgas pipe P7), and downstream of the separation section 20 (inflow section 26). And on the upstream side of the anode 18A of the second fuel cell stack 18 (regenerated fuel gas pipe P9). In the second heat exchange section 32, heat exchange is performed between the anode offgas G3 flowing through the anode offgas pipe P7 and the regenerated fuel gas G4 flowing through the regenerated fuel gas pipe P9. The anode off gas G3 is normally at a high temperature of about 650 ° C., and the regenerated fuel gas G4 flowing through the regenerated fuel gas pipe P9 is a temperature close to the appropriate temperature T0 of the separation unit 20. In the second heat exchange section 32, the temperature of the anode off gas G3 decreases, and the temperature of the regenerated fuel gas G4 increases.

  The third heat exchanging section 34 is vaporized on the downstream side of the separation section 20 (inflow section 26), upstream of the cathode 16B of the first fuel cell stack 16 (for the oxidizing gas pipe P5), and downstream of the combustor 40. It is provided on the upstream side of the vessel 12 (for the combustion exhaust pipe P10). In the third heat exchanging section 34, heat exchange is performed between the oxidizing gas G5 flowing through the oxidizing gas pipe P5 and the combustion exhaust gas G6 flowing through the combustion exhaust gas pipe P10. The oxidizing gas G5 flowing through the oxidizing gas pipe P5 has a temperature close to the appropriate temperature T0 of the separation unit 20. In the third heat exchange section 34, the oxidizing gas G5 supplied to the cathode 16B is heated by the combustion exhaust gas G6.

  The fourth heat exchange unit 36 is downstream of the separation unit 20 and upstream of the second heat exchange unit 32 (with respect to the regenerated fuel gas pipe P9), and downstream of the third heat exchange unit 34 and upstream of the carburetor 12. Heat exchange is performed between the regenerated fuel gas G4 flowing through the regenerated fuel gas pipe P9 and the combustion exhaust gas G6 flowing through the combustion exhaust gas pipe P10. The regenerated fuel gas G4 flowing through the regenerated fuel gas pipe P9 has a temperature close to the appropriate temperature T0 of the separation unit 20, and is heated by the combustion exhaust gas G6 in the fourth heat exchange unit 36.

  Next, the operation of the fuel cell system 10A of the present embodiment will be described.

  In the fuel cell system 10 </ b> A, methane, which is fuel from a gas source, and water from the tank 42 are supplied to the vaporizer 12. In the vaporizer 12, the supplied methane and water are mixed, and heat is obtained from the combustion exhaust gas G6 flowing through the combustion exhaust pipe P10, and the water is vaporized to become water vapor.

  Methane and water vapor are sent from the vaporizer 12 to the reformer 14 via the pipe P3. In the reformer 14, a fuel gas G1 containing about 600 ° C. containing hydrogen is generated by the reforming reaction. The fuel gas G1 is supplied to the anode 16A of the first fuel cell stack 16 via the fuel gas pipe P4.

At the cathode 16B of the first fuel cell stack 16, the permeated portion exhaust gas (mixed gas of air A, carbon dioxide, and water vapor) discharged from the permeated portion 26 of the separation portion 20 passes through the oxidizing gas pipe P5 as the oxidizing gas G5. It is supplied via. Thereby, in the 1st fuel cell stack 16, electric power generation is performed by the above-mentioned reaction. Due to the above reaction, the first fuel cell stack 16 generates heat, and power is generated at a temperature of about 650 ° C. Along with this power generation, the anode off gas G3 is discharged from the anode 16A of the fuel cell stack 16. Further, the cathode off gas G2 is discharged from the cathode 16B, and the cathode off gas G2 is supplied to the cathode 18B of the second fuel cell stack 18 through the cathode off gas pipe P6.

  The anode off-gas G3 discharged from the anode 16A is guided to the anode off-gas pipe P7, and flows into the inflow section 24 of the separation section 20 through the second heat exchange section 32 and the first heat exchange section 30. In the second heat exchange section 32, the temperature of the anode off gas G3 decreases to some extent from about 650 ° C. (for example, a decrease of about 80 ° C. to 140 ° C.), and in the first heat exchange section 30, the temperature of the anode off gas G3 Is lowered to a temperature close to the appropriate temperature T0.

  On the other hand, air A whose flow rate is controlled by feedback control of the temperature T of the separation unit 20 by the control unit 44 is sent from the air supply unit 46 to the permeation unit 26 of the separation unit 20 via the first heat exchange unit 30. The In the first heat exchange unit 30, the temperature of the air A is a temperature close to the appropriate temperature T0, that is, substantially the same temperature as the anode offgas G3 after the heat exchange is performed in the first heat exchange unit 30.

  The anode off gas G3 flows into the inflow part 24 of the separation part 20 through heat exchange in the second heat exchange part 32 and the first heat exchange part 30, and at least one of carbon dioxide and water vapor passes through the separation membrane 28. Then, it is separated by moving to the transmission part 26 side. The regenerated fuel gas G4 is sent out from the inflow section 24, and is heated to about 600 ° C. through the fourth heat exchange section 36 and the second heat exchange section 32, and the regenerated fuel gas pipe P9 causes the second fuel cell stack 18 to Supplied to the anode 18A.

  In the second fuel cell stack 18, power generation is performed by the above-described reaction. Due to the above reaction, the second fuel cell stack 18 generates heat, and power is generated at a temperature of about 650 ° C. The spent gas at the anode 18A and the cathode 18B is sent to the combustor 40 through the pipes P11 and P12, and is used for incineration by the combustor 40.

  The combustion exhaust gas G6 from the combustor 40 passes through the third heat exchange unit 34, the fourth heat exchange unit 36, and the vaporizer 12, and is sent to the tank 42 through the combustion exhaust gas pipe P10. The water vapor contained in the combustion exhaust gas G6 is cooled in the path from the vaporizer 12 to the tank 42 or in the tank 42, condensed, and stored in the tank 42. Other combustion exhaust gas is discharged from the tank 42.

On the other hand, the air A as the sweep gas that has flowed into the permeation section 26, together with the carbon dioxide and water vapor that have permeated through the separation membrane 28 and the gas in the anode off-gas G3 that has permeated through the separation membrane 28, is transmitted through the permeation section 26. Is sent from. The transmitted permeation portion exhaust gas passes through the fourth heat exchange portion 36 and the third heat exchange portion 34, and is supplied as the oxidizing gas G5 to the cathode 16B through the oxidizing gas pipe P5.

In the fuel cell system 10A of the present embodiment, air A as a sweep gas is supplied to the permeation side (permeation portion 26) of the separation membrane 28, so that the partial pressures of carbon dioxide and water vapor in the permeation portion 26 are reduced. As a result, at least one of carbon dioxide and water vapor contained in the anode offgas G3 flowing into the inflow portion 24 can be separated through the separation membrane 28 more.

In addition, since the anode offgas G3 and air A heat-exchanged in the first heat exchanging unit 30 are introduced into the separation unit 20 so as to approach the appropriate temperature T0, the separation unit 20 is maintained at the appropriate temperature T0 to maintain the separation membrane. 28 performances can be exhibited. As a result, at least one of carbon dioxide and water vapor can be largely separated from the anode off-gas G3, and the durability of the separation membrane 28 can be maintained. Then, since the regenerated fuel gas G4 with reduced carbon dioxide and water vapor is supplied to the second fuel cell stack 18 that reuses the anode off-gas G3, it is possible to efficiently generate power, and the performance of the fuel cell system 10A. Can be improved.

In addition, heat exchange in the first heat exchange unit 30 is performed between the air A that is a gas supplied to the separation unit 20 and the anode off gas G3, and the adjustment to the appropriate temperature T0 is performed by adjusting the flow rate of the air A. Since it is performed by controlling, the temperature of the separation part 20 can be adjusted easily.

In the present embodiment, the flow rate of the air A sent from the air supply unit 46 is adjusted by feeding back the temperature of the separation unit 20, but the air A and the anode offgas G3 sent from the first heat exchange unit 30 are adjusted. The temperature may be measured and the flow rate of the air A sent from the air supply unit 46 may be adjusted by feeding back the temperature.

Moreover, in this embodiment, since the temperature of the anode off gas G3 is lowered by the second heat exchange unit 32 upstream of the first heat exchange unit 30, the temperature adjustment range in the first heat exchange unit 30 can be reduced. it can. Further, since the temperature of the regenerated fuel gas G4 after passing through the separation unit 20 is raised by the second heat exchange unit 32, the temperature becomes close to a temperature suitable for power generation, and the power generation efficiency and thermal efficiency of the entire fuel cell system 10A can be improved. it can

In the present embodiment, since the permeation portion exhaust gas discharged from the permeation portion 26 of the separation portion 20 is introduced to the cathode 16B of the first fuel cell stack 16, introduction of air into the cathode 16B and the first The introduction of air into the heat exchange unit 30 can be performed using the same blower, and the fuel cell system 10A can have a simple configuration.

Further, in the present embodiment, the permeation portion exhaust gas discharged from the permeation portion 26 of the separation portion 20 is introduced into the cathode 16B and used for power generation, and then introduced into the cathode 18B of the second fuel cell stack 18 to generate power. Then, it is sent to the combustor 40 for combustion. The permeated portion exhaust gas may contain hydrogen, carbon monoxide, and other combustible substances due to leakage from the anode off-gas G3 in the separation membrane 28 or the like. According to the fuel cell system 10A of the present embodiment, hydrogen, carbon monoxide, and other combustible substances contained in the permeated portion exhaust gas can be burned and then released to the outside of the fuel cell system 10A. The safety of the fuel cell system 10A can be improved.

In the present embodiment, the permeation portion exhaust gas discharged from the permeation portion 26 is introduced into the cathode 16B, but the permeation portion exhaust gas may be directly introduced into the combustor 40. In this case, a blower for introducing air to the cathode 16B of the first fuel cell stack 16 may be prepared separately.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as 1st Embodiment, and description is abbreviate | omitted.

  FIG. 2 shows a fuel cell system 10B according to the second embodiment of the present invention. The fuel cell system 10B is different from the fuel cell system 10A described in the first embodiment in that the temperature of the air sent from the air supply unit 46 is increased to reach the first heat exchange unit 30. ing. Further, the flow rate of the air A sent from the air supply unit 46 is constant, and the temperature of the air supplied to the separation unit 20 and the temperature of the anode off gas G3 is adjusted by the flow rate of the air A-1 passing through the valve 48. Is different.

  The air supply pipe P8 connected to the air supply part 46 is branched into an air adjustment pipe P8-1 and an air temperature raising pipe P8-2 at the branching part B1, and joined at the joining part B2. The junction B <b> 2 is provided on the upstream side of the first heat exchange unit 30.

  A valve 48 is provided in the air adjustment pipe P8-1. The valve 48 is connected to the control unit 44. The air temperature raising pipe P8-2 is introduced into the fifth heat exchange unit 38. A combustion exhaust gas pipe P10 on the downstream side of the fourth heat exchange part 36 is introduced into the fifth heat exchange part 38, and the air A-2 passing through the air temperature raising pipe P8-2 passes through the combustion exhaust gas pipe P10. The temperature is raised by exchanging heat with the flowing combustion exhaust gas G6. An air temperature raising portion is formed by the air adjustment pipe P8-1, the valve 48, the fourth heat exchanging portion 36, and the air temperature raising pipe P8-2.

The control unit 44 controls the flow rate of the air A-1 that passes through the valve 48 so that the air A and the anode off gas G3 flowing into the separation unit 20 from the first heat exchange unit 30 approach the appropriate temperature T0. The control is performed by adjusting the flow rate of the air A-1 passing through the valve 48 based on the temperature of the separation unit 20 measured by the temperature sensor SS. Specifically, when the temperature T of the separation unit 20 is lower than the optimum temperature T0, the opening of the valve 48 is reduced to reduce the flow rate of the air A-1 passing through the valve 48, and the temperature T becomes the optimum temperature T0. Is higher, the flow rate of the air A-1 passing through the valve 48 is increased by increasing the opening degree of the valve 48. During the operation of the fuel cell system 10B, the control unit 44 feedback-controls the flow rate of the air A-1 passing through the valve 48 based on the temperature T, either constantly or intermittently, so that the temperature of the separation unit 20 is adjusted to the appropriate temperature T0 or It can be maintained at a temperature close to the appropriate temperature T0.

  According to the present embodiment, heat exchange in the first heat exchange unit 30 can be performed so that the separation unit 20 reaches the appropriate temperature T0 while maintaining the flow rate of the air A sent from the air supply unit 46 constant. it can. By maintaining the flow rate of the air A sent from the air supply unit 46 constant, the flow rate of the air A supplied to the transmission unit 26 can be ensured.

Further, the fuel cell system 10B can achieve the same effects as those of the other first embodiments.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as 1st, 2nd embodiment, and description is abbreviate | omitted.

  FIG. 3 shows a fuel cell system 10C according to a third embodiment of the present invention. The fuel cell system 10C adjusts both the flow rate of the air A sent from the air supply unit 46 and the flow rate of the air A-1 passing through the valve 48, as compared with the fuel cell system 10B described in the second embodiment. This is different in that the separation unit 20 is controlled to a temperature close to the appropriate temperature T0.

The control unit 44 is connected to the air supply unit 46 and the valve 48. In the control unit 44, the air A and the anode off gas G3 flowing into the separation unit 20 from the first heat exchange unit 30 pass through the air A sent from the air supply unit 46 and the valve 48 so as to approach the appropriate temperature T0. The flow rate of the air A-1 is controlled. Specifically, when the temperature T of the separation unit 20 measured by the temperature sensor SS is lower than the appropriate temperature T0, the output of the blower of the air supply unit 46 is lowered and the opening of the valve 48 is reduced, The flow rate of the air A sent from the air supply unit 46 and the flow rate of the air A-1 passing through the valve 48 are decreased. On the other hand, when the temperature T is higher than the appropriate temperature T0, the flow rate of the air A sent from the air supply unit 46 and the valve are increased by increasing the blower output of the air supply unit 46 and increasing the opening of the valve 48. The flow rate of air A-1 passing through 48 is increased. During operation of the fuel cell system 10C, the flow rate of the air A sent from the air supply unit 46 based on the temperature T of the separation unit 20 and the air A-1 passing through the valve 48 are always or intermittently controlled by the control unit 44. By feedback control of the flow rate, the temperature of the separation unit 20 can be maintained at the appropriate temperature T0 or a temperature close to the appropriate temperature T0.

  According to the present embodiment, by adjusting both the flow rate of the air A sent from the air supply unit 46 and the flow rate of the air A-1 passing through the valve 48, the separation unit 20 is adjusted to have the appropriate temperature T0. 1 Heat exchange in the heat exchange unit 30 is performed. Therefore, the temperature of the separation unit 20 can be adjusted more flexibly.

Further, the fuel cell system 10C can achieve the same effects as those of the first and second embodiments.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as 1-3 embodiment, and description is abbreviate | omitted.

  FIG. 4 shows a fuel cell system 10D according to a fourth embodiment of the present invention. The fuel cell system 10D is different from the fuel cell system 10A described in the first embodiment in that it does not have the second fuel cell stack 18.

  The regenerated fuel gas pipe P9 connected to the separation unit 20 is branched by a branching part B3 provided on the downstream side of the fourth heat exchange unit 36. One of the branched regenerative fuel gas pipes P9-1 is connected to the pipe P3 via the second heat exchange section 32. The other branched regenerative fuel gas pipe P <b> 9-2 is connected to the combustor 40. In the branch portion B3, the regenerated fuel gas G4 is branched to the regenerated fuel gas pipe P9-1 and the regenerated fuel gas pipe P9-2. A blower 52 is provided on the upstream side of the second heat exchange unit 32 of the regenerated fuel gas pipe P9-1. The blower 52 distributes the regenerated fuel gas G4 in the regenerated fuel gas pipe P9-1 toward the pipe P3.

The regenerated fuel gas G4 introduced into the reformer 14 via the regenerated fuel gas pipe P9-1 is mixed with the fuel gas G1 supplied from the vaporizer 12, and supplied to the anode 16A. The regenerated fuel gas G4 introduced into the combustor 40 through the regenerated fuel gas pipe P9-2 is burned in the combustor 40. The cathode off gas G2 discharged from the cathode 16B is introduced into the combustor 40 via the cathode off gas pipe P6.

  In the fuel cell system 10D of this embodiment, the anode off-gas G3 that is the spent fuel in the first fuel cell stack 16 is regenerated and reused in the first fuel cell stack 16 again. It has become. In this embodiment, the same effect as that of the first embodiment can be obtained.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as 1-4th embodiment, and description is abbreviate | omitted.

  FIG. 5 shows a fuel cell system 10E according to the fifth embodiment of the present invention. The fuel cell system 10E is different from the fuel cell system 10D described in the fourth embodiment in that the temperature of the air sent from the air supply unit 46 is raised as in the second embodiment. That is, the flow rate of the air A sent from the air supply unit 46 is constant, and the temperature of the air supplied to the separation unit 20 and the temperature of the anode off gas G3 is adjusted by the flow rate of the air A-1 passing through the valve 48. Is different.

The air supply pipe P8 connected to the air supply part 46 is branched into an air adjustment pipe P8-1 and an air temperature raising pipe P8-2 at the branching part B1, and joined at the joining part B2. The junction B <b> 2 is provided on the upstream side of the first heat exchange unit 30.

  A valve 48 is provided in the air adjustment pipe P8-1. The valve 48 is connected to the control unit 44. The air temperature raising pipe P8-2 is introduced into the fifth heat exchange unit 38. A combustion exhaust gas pipe P10 on the downstream side of the fourth heat exchange part 36 is introduced into the fifth heat exchange part 38, and the air A-2 passing through the air temperature raising pipe P8-2 passes through the combustion exhaust gas pipe P10. The temperature is raised by exchanging heat with the flowing combustion exhaust gas G6.

In the control unit 44, as in the second embodiment, the air A-1 that passes through the valve 48 so that the air A and the anode offgas G3 flowing from the first heat exchange unit 30 to the separation unit 20 approach the appropriate temperature T0. To control the flow rate.

  According to the present embodiment, heat exchange in the first heat exchange unit 30 can be performed so that the separation unit 20 reaches the appropriate temperature T0 while maintaining the flow rate of the air A sent from the air supply unit 46 constant. it can. By maintaining the flow rate of the air A sent from the air supply unit 46 constant, the flow rate of the air A supplied to the transmission unit 26 can be ensured.

Further, the fuel cell system 10E can achieve the same effects as those of the other first embodiments.

[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as 1-5 embodiment, and description is abbreviate | omitted.

  FIG. 6 shows a fuel cell system 10F according to the sixth embodiment of the present invention. Compared with the fuel cell system 10E described in the fifth embodiment, the fuel cell system 10F is similar to the third embodiment in that the flow rate of the air A sent from the air supply unit 46 and the air A passing through the valve 48 are the same. The difference is that the separation unit 20 is controlled to a temperature close to the appropriate temperature T0 by adjusting both the flow rates of -1.

The control unit 44 is connected to the air supply unit 46 and the valve 48. In the control unit 44, as in the third embodiment, air sent from the air supply unit 46 so that the air A and the anode off gas G3 flowing from the first heat exchange unit 30 to the separation unit 20 approach the appropriate temperature T0. A and the flow rate of the air A-1 passing through the valve 48 are controlled.

  According to the present embodiment, by adjusting both the flow rate of the air A sent from the air supply unit 46 and the flow rate of the air A-1 passing through the valve 48, the separation unit 20 is adjusted to have the appropriate temperature T0. 1 Heat exchange in the heat exchange unit 30 is performed. Therefore, the temperature of the separation unit 20 can be adjusted more flexibly.

In addition, the fuel cell system 10F can achieve the same effects as the other fifth and sixth embodiments.

[Seventh Embodiment]
Next, a seventh embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as 1-6th embodiment, and description is abbreviate | omitted.

  FIG. 7 shows a fuel cell system 10G according to a seventh embodiment of the present invention. The fuel cell system 10G is different from the fuel cell system 10A described in the first embodiment in that it includes a third fuel cell stack 17.

  The basic configuration of the third fuel cell stack 17 is the same as that of the first fuel cell stack 16, and includes an anode 17A corresponding to the anode 16A and a cathode 17B corresponding to the cathode 16B. The third fuel cell stack 17 is arranged in parallel with the first fuel cell stack 16 in the fuel cell system 10G. In FIG. 7, the second fuel cell stack 18 and the third fuel cell stack 17 are illustrated separately from the reformer 14, but actually the second fuel cell stack 18 and the third fuel cell stack are illustrated. 17 is disposed adjacent to the reformer 14 in the same manner as the first fuel cell stack 16, and heat exchange is performed.

The fuel gas pipe P4 connected to the reformer 14 is branched from the fuel gas pipe P4-2 at the branching section B4. The fuel gas pipe P4 is connected to the anode 16A and supplies the fuel gas G1 from the reformer 14 to the anode 16A. The fuel gas pipe P4-2 is connected to the anode 17A and supplies the fuel gas G1 from the reformer 14 to the anode 17A. An anode offgas pipe P7 is connected to the anode 17A, and the anode offgas pipe P7-2 is joined at the junction B5 upstream of the anode offgas pipe P7 and the second heat exchange section 32. From the anode 17A, the used anode off gas G3 is sent out and flows into the inflow portion 24 of the separation portion 20 through the anode off gas pipes P7-2 and P7.

  An oxidant gas pipe P5-2 branched from the oxidant gas pipe P5 at the branch part B6 on the downstream side of the third heat exchanging part 34 is connected to the cathode 17B. The oxidizing gas G5 is supplied to the cathode 17B via the oxidizing gas pipe P5-2. The spent gas discharged from the cathode 17B is merged with the cathode offgas pipe P6 at the merging portion B7 and introduced into the cathode 18B.

  As described above, by having the third fuel cell stack 17 arranged in parallel with the first fuel cell stack 16, power generation in the first stage of the fuel cell system 10G is performed by the first fuel cell stack 16 and the third fuel cell stack 16. This is performed in the fuel cell stack 17. Then, the anode off-gas G3 after being used in the first fuel cell stack 16 and the third fuel cell stack 17 is regenerated to the regenerated fuel gas G4 by the separation unit 20, and the second fuel cell stack 18 in the second stage is regenerated. Can be used for power generation.

  According to the fuel cell system 10G of the present embodiment, the difference in operating rate between the first and second fuel cell stacks is reduced, and the power generation efficiency in the fuel cell system 10G18 can be increased.

[Eighth Embodiment]
Next, an eighth embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as 1-7th embodiment, and description is abbreviate | omitted.
FIG. 8 shows a fuel cell system 10H according to an eighth embodiment of the present invention. The fuel cell system 10H differs from the fuel cell system 10G described in the seventh embodiment in that the temperature of the air sent from the air supply unit 46 is raised, as in the second and fifth embodiments. Yes. That is, the flow rate of the air A sent from the air supply unit 46 is constant, and the temperature of the air supplied to the separation unit 20 and the temperature of the anode off gas G3 is adjusted by the flow rate of the air A-1 passing through the valve 48. Is different.

The air supply pipe P8 connected to the air supply part 46 is branched into an air adjustment pipe P8-1 and an air temperature raising pipe P8-2 at the branching part B1, and joined at the joining part B2. The junction B <b> 2 is provided on the upstream side of the first heat exchange unit 30.

  A valve 48 is provided in the air adjustment pipe P8-1. The valve 48 is connected to the control unit 44. The air temperature raising pipe P8-2 is introduced into the fifth heat exchange unit 38. A combustion exhaust pipe P10 on the downstream side of the fourth heat exchange section 36 is introduced into the fifth heat exchange section 38, and the air A-2 passing through the air temperature raising pipe P8-2 is connected to the combustion exhaust pipe P10. The temperature is raised by exchanging heat between the two.

In the control unit 44, as in the second and fifth embodiments, the air A passing through the valve 48 so that the air A and the anode offgas G3 flowing from the first heat exchange unit 30 to the separation unit 20 approach the appropriate temperature T0. -1 flow rate is controlled.

  According to the present embodiment, heat exchange in the first heat exchange unit 30 can be performed so that the separation unit 20 reaches the appropriate temperature T0 while maintaining the flow rate of the air A sent from the air supply unit 46 constant. it can. By maintaining the flow rate of the air A sent from the air supply unit 46 constant, the flow rate of the air A supplied to the transmission unit 26 can be ensured.

Further, the fuel cell system 10H can achieve the same effects as those of the other first embodiments.

[Ninth Embodiment]
Next, a ninth embodiment of the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as 1st-8 embodiment, and description is abbreviate | omitted.

  FIG. 9 shows a fuel cell system 10I according to the ninth embodiment of the present invention. Compared to the fuel cell system 10H described in the eighth embodiment, the fuel cell system 10I passes through the valve 48 and the flow rate of the air A delivered from the air supply unit 46, as in the third and sixth embodiments. The difference is that the separation unit 20 is controlled to a temperature close to the appropriate temperature T0 by adjusting both the flow rates of the air A-1.

The control unit 44 is connected to the air supply unit 46 and the valve 48. In the control unit 44, as in the third and sixth embodiments, the air A and the anode off gas G3 flowing from the first heat exchange unit 30 to the separation unit 20 are sent from the air supply unit 46 so as to approach the appropriate temperature T0. And the flow rate of the air A-1 passing through the valve 48 is controlled.

  According to the present embodiment, by adjusting both the flow rate of the air A sent from the air supply unit 46 and the flow rate of the air A-1 passing through the valve 48, the separation unit 20 is adjusted to have the appropriate temperature T0. 1 Heat exchange in the heat exchange unit 30 is performed. Therefore, the temperature of the separation unit 20 can be adjusted more flexibly.

The fuel cell system 10I can also achieve the same effects as the other seventh and eighth embodiments.

In addition, arrangement | positioning of the 2nd heat exchange part 32-the 5th heat exchange part 38 in said 1st-9th embodiment is not limited to said arrangement | positioning, You may change suitably. Further, as a means for separating carbon dioxide and water vapor from the anode off gas G3, for example, other means such as a water condenser, a water vapor adsorbing material, a carbon dioxide absorbing material, a carbon dioxide adsorbing material may be used in combination with the separation unit. .

Moreover, in said 1st-9th embodiment, the flow volume of the air A which flows out from the air supply part 46 so that the isolation | separation part 20 may approach suitable temperature T0 in the control part 44, and the air which flows in into the 1st heat exchange part 30 Although the temperature of A is controlled, the control part 44 is not necessarily required. For example, the flow rate of the air A that flows out from the air supply unit 46 so that the separation unit 20 approaches the appropriate temperature T0 and the temperature of the air A that flows into the first heat exchange unit 30 are obtained in advance through experiments and the like. Each unit (the air supply unit 46 and the valve 48) may be set so that the flow rate of the air A and the temperature of the air A flowing into the first heat exchange unit 30 are obtained.

Furthermore, the present invention is not limited to the first to ninth embodiments described above, and is implemented by a person skilled in the art in combination with the above-described embodiments within the technical idea of the present invention. Moreover, in this invention, the installation position of a heat exchanger, a combination, etc. are not limited to these embodiment, for example. Moreover, you may use means other than a heat exchanger for the heating and cooling of various fluids, such as gas and water.

10A to 10I Fuel cell system 16 First fuel cell stack (fuel cell), 17 Third fuel cell stack (fuel cell)
18 Second fuel cell stack (fuel cell),
16A, 17A, 18A Anode (fuel electrode)
16B, 17B, 18B Cathode (Air electrode)
20 separation part, 24 inflow part, 26 permeation part, 28 separation membrane 30 first heat exchange part, 32 second heat exchange part 46 air supply part, P8-1 air regulating pipe, 48 valve, 36 fourth heat exchange part P8 -2 Air temperature riser (Air temperature riser)
40 combustor, 44 control unit, P5 oxidizing gas pipe (oxidizing gas introduction path)
G3 anode off gas, G4 regenerated fuel gas

Claims (9)

A fuel cell that generates power from fuel gas supplied to the fuel electrode and air supplied to the air electrode, wherein anode off-gas is discharged from the fuel electrode and cathode off-gas is discharged from the air electrode;
An inflow part into which the anode offgas is introduced; and a permeation part partitioned from the inflow part by a separation membrane that separates at least one of carbon dioxide and water vapor from the anode offgas; A separation unit that sends out regenerated fuel gas in which the concentration of at least one of the water vapor is reduced;
An air supply unit for supplying air to the permeation unit as a sweep gas;
A fuel cell system comprising: a first heat exchanging unit that is provided upstream of the separation unit and exchanges heat between the anode off gas and air from the air supply unit.   2. The fuel cell system according to claim 1, wherein the first heat exchange unit performs heat exchange between the anode off gas and the air from the air supply unit in a parallel flow manner. An air temperature raising unit that is provided between the air supply unit and the first heat exchange unit and raises the temperature of the air from the air supply unit;
A control unit for controlling the temperature of the air flowing out from the air temperature raising unit according to the temperature of the separation unit;
A fuel cell system according to claim 1 or 2, further comprising:   The fuel cell system according to claim 3, wherein a flow rate of air flowing from the air supply unit to the first heat exchange unit is constant.   The fuel cell system according to any one of claims 1 to 4, further comprising a control unit that controls a flow rate of air flowing into the first heat exchange unit according to a temperature of the separation unit.   The fuel cell system according to any one of claims 1 to 5, further comprising an oxidizing gas introduction path for introducing the gas discharged from the permeation unit into the air electrode. Equipped with a combustor to burn flammable gas,
The fuel cell system according to any one of claims 1 to 6, wherein the gas discharged from the permeation unit is directly or indirectly introduced into the combustor.   The fuel cell includes: a first fuel cell that sends an anode off gas to the inflow portion of the separation portion; and a second fuel cell in which the regenerated fuel gas is supplied to the fuel electrode as the fuel gas. The fuel cell system according to any one of claims 1 to 7.   9. The apparatus according to claim 1, further comprising a second heat exchange unit that exchanges heat between the anode off-gas flowing upstream from the first heat exchange unit and the regenerated fuel gas. The fuel cell system according to item.

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