JP2007042437A - Solid oxide fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an excellent energy efficiency with a rational and effective use of exhaust heat of solid oxide fuel cell while restraining heat damage or the like due to high-temperature exhaust heat, in a solid oxide fuel cell system generating power by the solid oxide fuel cell using solid oxide as an electrolyte and utilizing the exhaust heat obtained at the same time. <P>SOLUTION: The system is provided with a burner part 6 capable of combusting by mixing fuel G to exhaust gas E exhausted from the solid oxide fuel cell 1 to an exhaust channel 5, a steam generating part 10 generating steam S supplied to a steam consuming part X by supplying liquid W in an evaporating tube 11 arranged at the exhaust channel 5, and a thermal power generating part 20 generating power with the use of a temperature difference between the exhaust gas E and the evaporating tube 11 by installing a thermoelectric conversion material 21 on an outer surface of the evaporating tube 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a solid oxide fuel cell system that generates electric power using a solid oxide fuel cell using a solid oxide as an electrolyte and uses exhaust heat obtained at the same time.

The solid oxide fuel cell as described above generates power by an electrochemical reaction between hydrogen supplied to one fuel electrode and oxygen supplied to the other air electrode with a solid oxide electrolyte interposed therebetween. It is configured as follows.
That is, in the air electrode, oxygen reacts with electrons to form oxygen ions, and in the electrolyte made of the solid oxide, the oxygen ions are transported from the air electrode side to the fuel electrode side. By reacting with ions to generate water vapor and electrons, an electromotive force is generated between the air electrode and the fuel electrode to generate electric power.

Since such a solid oxide fuel cell has an extremely high operating temperature (for example, about 800 ° C. to 1000 ° C.), high-temperature heat is discharged at the same time as power generation. Exhaust of about 380 ° C. is discharged.
And in the conventional solid oxide fuel cell system provided with the solid oxide fuel cell, it is important to improve energy efficiency by effectively utilizing such high-temperature exhaust heat.

  As a conventional method for effectively using exhaust heat, a method of generating power by driving a steam turbine with steam generated by exhaust heat (see, for example, Patent Document 1 and Patent Document 2), exhaust heat, A method of generating power by the Seebeck effect of a thermoelectric conversion material using a temperature difference from the atmosphere is known (for example, see Patent Document 3), and such generated power is used as, for example, a solid oxide fuel. In addition to the power generated by the battery, it can be used by being supplied to the power consumption unit.

  The steam turbine described in Patent Document 2 is a disk type radial flow turbine having a feature that a large number of combinations of thin fixed disks and rotating disks are densely stacked on the same axis, and is highly efficient and downsized. Can be realized at the same time.

  On the other hand, the thermoelectric conversion material described in Patent Document 3 is a complex oxide having a characteristic composition containing, for example, Bi, Sr, Te, Co and O as constituent elements, and has excellent heat resistance and high thermoelectric conversion efficiency. It is supposed to be possible.

  Further, the exhaust heat of the fuel cell is used as a heat source for generating hot water for hot water supply or heating, or a heat source for preheating air supplied to the fuel cell, in addition to being used for power generation as described above. May be used.

JP 2002-50387 A ([Claim 6], paragraph [0021], etc.) JP-A-2005-42567 ([Claim 1], paragraph [0021], etc.) JP 2003-152230 A

For example, in order to effectively utilize the high-temperature exhaust heat of a solid oxide fuel cell, water is heated by heat exchange with the exhaust discharged from the air electrode of the solid oxide fuel cell and used for driving a steam turbine, etc. In the solid oxide fuel cell system configured to generate the generated water vapor, there is a case where a sufficient amount of water vapor that can be effectively used cannot be generated due to a decrease in the exhaust temperature.
In order to generate a sufficient amount of water vapor, it is conceivable that fuel is supplied to the exhaust of the solid oxide fuel cell and burned to raise the exhaust temperature. There is a concern that the outer surface temperature of the evaporation pipe for generating water vapor by supplying water to the inside excessively increases the temperature and causes thermal damage.

  On the other hand, in order to effectively utilize the high-temperature exhaust heat of the solid oxide fuel cell, the solid oxide fuel cell is configured to generate power by the thermoelectric conversion material using the temperature difference between the high-temperature exhaust heat and the atmosphere. In the system, there is a problem that heat loss is caused by radiating the heat of the heat sink of the thermoelectric conversion material to the atmosphere, and the energy efficiency cannot be sufficiently improved.

  The present invention has been made in view of the above problems, and an object of the present invention is to exhaust heat from a solid oxide fuel cell while suppressing thermal damage due to high temperature exhaust heat in the solid oxide fuel cell system. It is in the point which provides the technology which implement | achieves the outstanding energy efficiency using rationally effectively.

  In order to achieve the above object, a solid oxide fuel cell system according to the present invention generates power by a solid oxide fuel cell using a solid oxide as an electrolyte, and at the same time uses solid heat to obtain the exhaust heat. A physical fuel cell system, the first characteristic configuration of which is disposed in the exhaust passage, and a burner section capable of combusting fuel mixed with the exhaust gas discharged from the solid oxide fuel cell into the exhaust passage, and the exhaust passage. A steam generator for supplying liquid into the evaporation pipe and generating steam to be supplied to the steam consuming section; and a thermoelectric conversion material is provided on the outer surface of the evaporator pipe to utilize the temperature difference between the exhaust and the evaporator pipe And a thermoelectric generator that generates electric power.

According to the first characteristic configuration, the heat of the high-temperature exhaust discharged from the solid oxide fuel cell is effectively used as an energy source for generating steam by the steam generation unit and generating power by the thermoelectric generation unit. Thus, a solid oxide fuel cell system with excellent energy efficiency can be realized.
That is, the steam generation unit can generate a vapor by heating the liquid using the relatively high temperature exhaust discharged from the solid oxide fuel cell, and the vapor can be used as heat. At the same time, the Seebeck effect of the thermoelectric conversion material by utilizing the temperature difference between the relatively high temperature exhaust discharged from the solid oxide fuel cell and the relatively low temperature liquid supplied to the steam generator by the thermoelectric generator. For example, in addition to the generated power of the solid oxide fuel cell, the generated power can be supplied to the power consuming unit and used, or can be used for another application.
Furthermore, since the thermoelectric generator is configured by providing a thermoelectric conversion material with excellent heat resistance on the outer surface of the vapor generating section, the steam pipe is brought into direct contact with the relatively high temperature exhaust gas. Can be prevented from being thermally damaged.

  The second characteristic configuration of the solid oxide fuel cell system according to the present invention is that the air supplied to the solid oxide fuel cell is heated in the exhaust passage by heat exchange with the exhaust downstream of the evaporation pipe. It is in the point provided with the air preheating part.

  According to the second characteristic configuration, the air of the solid oxide fuel cell is heated in the exhaust passage for the exhaust downstream of the evaporation pipe, that is, for steam generation by the steam generation unit and power generation by the thermoelectric generation unit. Heating by heat exchange with the relatively low temperature exhaust gas after being recovered makes it possible to use the heat of the exhaust gas for preheating air supplied to the solid oxide fuel cell, thereby further improving energy efficiency. Improvement can be realized.

A third characteristic configuration of the solid oxide fuel cell system according to the present invention is a steam turbine power generation capable of generating power by rotating a steam turbine by the generated steam as a steam consuming section that consumes the generated steam of the steam generating section. Part, and
A power load detecting means for detecting a power load in a power consuming unit to which the generated power of the solid oxide fuel cell and the steam turbine power generating unit is supplied;
Adjusting a steam supply amount to the steam turbine power generation unit, and adjusting a power generation output of the steam turbine power generation unit;
A steam power generation output control means for controlling the steam power generation output adjustment means based on the detection result of the power load detection means.

According to the third characteristic configuration, the steam generated in the steam generation unit is supplied to the steam turbine power generation unit as a steam consumption unit to generate power, and the generated power is generated by the solid oxide fuel cell. In combination with or separately from the power consumption unit, it can be used effectively.
Further, based on the power load in the power consumption section detected by the power load detection means, the steam supply amount to the steam turbine power generation section adjusted by the steam power generation output adjustment means is controlled to generate power from the steam turbine power generation section. The output can be made suitable for the power load in the power consuming unit. Therefore, it is possible to stabilize the generated power that the solid oxide fuel cell should supply to the power consuming unit, and to suppress fluctuations in the power generation output of the solid oxide fuel cell.

A fourth characteristic configuration of the solid oxide fuel cell system according to the present invention includes a first heat exchange unit that heats hot and cold water by heat exchange with the exhaust downstream of the evaporation pipe in the exhaust passage,
And a second heat exchange unit that heats the hot water heated by the first heat exchange unit by heat exchange with the steam discharged from the steam turbine power generation unit.

  According to the fourth characteristic configuration, in the first heat exchanging section, hot water for hot water supply or heating is used, exhaust in the exhaust passage downstream of the evaporation pipe, that is, steam generation by the steam generation section and the above Heating by heat exchange with a relatively low temperature exhaust after heat recovery for power generation by the thermoelectric generator uses the heat of the exhaust for hot water supply, heating, etc. Improvement can be realized. Further, in the second heat exchanging section, the hot water heated in the first heat exchanging section is recovered from the steam discharged from the steam turbine power generation section, that is, the heat recovered for power generation by the steam turbine power generation section. 1 Heat can be heated to a higher temperature by heat exchange with steam higher than the exhaust gas supplied to the heat exchange section, and the hot water can be effectively used for hot water supply, heating, and the like.

According to a fifth characteristic configuration of the solid oxide fuel cell system according to the present invention, the vapor generating section is disposed on a side of the evaporation pipe, and a lower end portion and an upper end portion of the evaporation pipe are connected to each other so that a liquid is contained therein. A gas-liquid separator to be supplied, and configured to take out steam from above in the gas-liquid separator;
A latent heat storage material having a melting point higher than the boiling point of the liquid is provided in the gas-liquid separator in a state where heat can be exchanged with the liquid in the gas-liquid separator.

According to the fifth characteristic configuration, as the liquid in the evaporation pipe is heated and evaporated by heat exchange with the exhaust flowing through the exhaust passage, the liquid stored in the gas-liquid separator included in the steam generation unit Can be supplied to the inside from the lower end portion of the evaporation pipe disposed on the side of the gas-liquid separator. Moreover, since the vapor | steam produced | generated when the liquid evaporated in the evaporation pipe is discharged | emitted upwards in a gas-liquid separator via the upper end part, the condensed water contained in the vapor | steam is again stored in a gas-liquid separator. Separating in the form, the vapor in an appropriate state can be taken out from above in the gas-liquid separator.
Furthermore, even when the temperature and amount of steam supplied from the evaporation pipe to the gas-liquid separator fluctuate, the latent heat storage material provided in the gas-liquid separator in a state where heat can be exchanged with the liquid evaporates. By storing and releasing the latent heat at a temperature in the vicinity of the melting point higher than the boiling point of the liquid evaporated in the tube, the temperature and amount of the steam taken out from above the gas-liquid separator can be stabilized.

A sixth characteristic configuration of the solid oxide fuel cell system according to the present invention is a steam that is operated by power generated by the thermoelectric generator in a steam passage through which the steam generated by the steam generator circulates and superheats the generated steam. With a heater,
A latent heat storage material having a melting point higher than the boiling point of the liquid is provided in the steam channel in a state in which heat can be exchanged with the steam in the steam channel.

According to the sixth characteristic configuration, the generated power of the thermoelectric generator is supplied as the operating power of the steam heater, and the steam generated by the steam generator is converted into high-temperature superheated steam that can be used effectively. Can be heated.
Furthermore, even when the temperature and amount of the steam generated in the steam generating section fluctuate, the latent heat storage material provided in the steam channel in a state where heat can be exchanged with the steam is more than the boiling point of the liquid that evaporates in the evaporation pipe. By storing and releasing the latent heat at a temperature near the high melting point, the temperature and amount of the steam supplied through the steam flow path can be stabilized.

A seventh characteristic configuration of the solid oxide fuel cell system according to the present invention includes a pure water generating unit that purifies tap water to generate pure water, and steams the fuel by steam generated by heating the pure water. A reforming section for reforming and generating hydrogen to be supplied to the solid oxide fuel cell,
The steam generation unit is configured to generate water vapor by supplying the pure water supplied from the pure water generation unit as the liquid to the evaporation pipe.

According to the seventh characteristic configuration, since the steam generating unit generates steam, the steam that is generated is supplied to, for example, a chamber in which the object to be cooked is stored to cook the object to be cooked. Equipment, portable cleaning equipment for cleaning by jetting water vapor, humidifying equipment for supplying water vapor to the room to humidify the room, washing the tableware by jetting water vapor to the tableware storage part in which the tableware is stored Efficient use by supplying to steam consumption parts such as dishwashing equipment that performs cooking, hot water generator that mixes water with water vapor to produce hot water, and a cooking heater that sprays water vapor on food to heat the food can do.
Further, the pure water generated in the pure water generation unit is supplied to the steam generation unit for steam reforming of fuel in the reforming unit without installing a new device for generating pure water. In addition, problems such as poor liquid flow and poor heat transfer due to accumulation of impurities such as scale in the evaporation tube can be prevented.

An embodiment of a solid oxide fuel cell system according to the present invention will be described with reference to FIG.
A solid oxide fuel cell system (hereinafter referred to as “the system of the present invention”) 100 generates power using a solid oxide fuel cell (hereinafter referred to as “SOFC”) 1 using a solid oxide as an electrolyte. In addition, the exhaust heat obtained at the same time is used.
The system 100 of the present invention will be described later in detail, but the burner section 6 is combustible by mixing the fuel G with the exhaust E discharged from the SOFC 1 into the exhaust passage 5 and the evaporation disposed in the exhaust passage 5. A steam generator 10 that supplies water W (an example of liquid) into the pipe 11 to generate water vapor S (an example of steam) that is supplied to the steam consumption unit X, and a thermoelectric conversion material 21 on the outer surface of the evaporator 11. Provided with the thermoelectric generator 20 that generates electricity using the temperature difference between the exhaust E and the evaporation pipe 11, thereby suppressing the heat damage of the evaporation pipe 11 due to high-temperature exhaust heat and the like, and simultaneously obtaining exhaust heat It is configured to realize excellent energy efficiency by rationally and effectively utilizing the above.

  The SOFC 1 having the same configuration as that of a known one can be used, so that the illustration is omitted, but a solid oxide such as yttria-stabilized zirconia, scandia-stabilized zirconia or ceria-based oxide having ionic conductivity is used as an electrolyte. A porous fuel cell and a fuel electrode are provided on both sides of the electrolyte.

  In such SOFC1, as shown in [Chemical Formula 1] below, oxygen supplied at the air electrode reacts with electrons to become oxygen ions, and the oxygen ions are carried to the fuel electrode through the electrolyte, and the fuel The hydrogen supplied at the electrode reacts with oxygen ions carried through the electrolyte to generate water vapor and electrons, thereby generating an electromotive force between the air electrode and the fuel electrode to generate power. ing. Note that the DC power generated by the SOFC 1 is converted into AC power by the DC / AC inverter 81, for example, and then supplied to and consumed by the power consuming unit 80 such as an electric device.

[Chemical 1]
(Air electrode) O ₂ + 4e ⁻ → 2O ²⁻
(Fuel electrode) 2H ₂ +40 ²⁻ → 2H ₂ O + 4e ⁻

Also, air A containing oxygen is supplied to the air electrode by a fan 32, while hydrogen obtained by steam reforming a fuel G such as city gas in the reforming unit 2 is supplied to the fuel electrode. A hydrogen-enriched gas containing is supplied.
Further, the steam used in the reforming unit 2 purifies the water W supplied from the tap water in the pure water generation unit 3 to generate pure water, and the pure water is heated in the reforming unit 2. can get.

Further, since the operating temperature of SOFC 1 is very high (for example, about 800 ° C. to 1000 ° C.), high-temperature water vapor is discharged from the fuel electrode, while oxygen is consumed from the air electrode. High-temperature heat is discharged simultaneously with power generation, such as exhaust E, which is high-temperature air.
Thus, the exhaust E discharged from the SOFC 1 to the exhaust passage 5 is at a relatively high temperature of about 380 ° C., and further, for example, about 10 vol% of unreacted oxygen remains.

  The burner unit 6 is configured to be able to burn by mixing the fuel G with the exhaust E discharged from the SOFC 1 to the exhaust passage 5. That is, the burner unit 6 mixes the fuel G with the exhaust E discharged from the SOFC 1 at the entrance of the exhaust passage 5 in a form in which the fuel G is ejected with the flow rate adjustment by the adjusting valve 7. Combustion is performed using oxygen remaining in E.

Further, the oxygen concentration of the exhaust E discharged from the SOFC 1 is sufficient for burning the fuel G. However, the oxygen concentration in the atmosphere is about 21 vol%, and is about 10 vol%. Slightly lower. Therefore, in the burner part 6, since the fuel G is combusted using low oxygen exhaust gas, NOx reduction by slow combustion is realized.
Further, when the fuel G is combusted using the high-temperature exhaust E discharged from the SOFC 1 in the burner unit 6, the exhaust E flowing through the exhaust passage 5 becomes very high at 800 ° C. or higher.

The steam generation unit 10 is configured to generate water vapor S by supplying water W into the evaporation pipe 11 disposed in the exhaust passage 5 and heating it. That is, the steam generating unit 10 includes an evaporation pipe 11 made of a highly heat conductive copper pipe or the like meandering from the lower side to the upper side in the exhaust passage 5 through which the exhaust E flows, and the side of the evaporation pipe 11 And a gas-liquid separator 12 to which the lower end and upper end of the evaporation pipe 11 are connected and water is supplied to the inside.
Then, water W is supplied into the evaporation pipe 11 from the lower side of the gas-liquid separator 12 through the lower end portion of the evaporation pipe 11, and the water W is heated by the exhaust E through the evaporation pipe 11 in the exhaust passage 5. The steam S generated in the evaporation pipe 11 flows out from the upper end of the evaporation pipe 11 to the upper side in the gas-liquid separator 12, and the steam S flows from the upper side in the gas-liquid separator 12 to the steam flow path. 15 is configured to be supplied to a steam consumption unit X described later.
In the gas-liquid separator 12, even when the water vapor S flowing out from the upper end of the evaporation pipe 11 to the upper side of the gas-liquid separator 12 is condensed, the condensed water is again stored in the gas-liquid separator 12 and is evaporated. Will be supplied into the evaporation pipe 11 from the lower end portion.

Further, in this gas-liquid separator 12, a latent heat storage material 13 having a melting point higher than the boiling point of the water W is filled in an accommodating portion provided along the inner wall surface, and the water W in the gas-liquid separator 12 is filled. In a state in which heat exchange is possible. Therefore, even when the temperature and amount of the water vapor S supplied from the evaporation pipe 11 to the gas-liquid separator 12 fluctuate, the water in which the latent heat storage material 13 provided in the gas-liquid separator 12 evaporates in the evaporation pipe. By storing and releasing the latent heat at a temperature in the vicinity of the melting point higher than the boiling point of W, the temperature and amount of the water vapor S taken out from above in the gas-liquid separator 12 can be stabilized.
As the latent heat storage material 13 can be appropriately using a known phase change material, such as MgCl ₂ or a saccharide having a melting point of about 120 ° C. to 190 ° C..

Further, in the steam generation unit 10, the pure water generated in the pure water generation unit 3 described above is supplied into the gas-liquid separator 12 by the supply pump 46 in order to prevent scale generation in the evaporation pipe 11. It is comprised so that it may be supplied as.
Further, a water level sensor 14 for detecting the water level is provided in the gas-liquid separator 12, and the control device 70 including a computer or the like is controlled by the supply pump 46 based on the water level detected by the water level sensor 14. By controlling the amount of water W supplied into the gas-liquid separator 12, the water level in the gas-liquid separator 12 is maintained within an appropriate range.

  A pressure sensor 8 that detects the pressure of the water vapor S in the gas-liquid separator 12 is provided above the gas-liquid separator 12. Based on the pressure of the water vapor S detected by the pressure sensor 8, the control device 70 controls the supply amount of the fuel G to the burner unit 6 by the regulating valve 7, that is, the combustion amount of the fuel G in the burner unit 6. Thus, the pressure of the water vapor S is maintained within an appropriate range, so that the water vapor S is stably generated from the steam generation unit 10.

The thermoelectric generator 20 utilizes the Seebeck effect, and is provided with a thermoelectric conversion material 21 on the outer surface of the evaporation pipe 11 of the steam generator 10, and is heated by high-temperature exhaust E and water W that circulates in the exhaust passage 5. Power generation is performed by utilizing a temperature difference from the cooled low-temperature evaporator tube 11. As the thermoelectric conversion material 21, a known composite oxide having excellent heat resistance and high thermoelectric conversion efficiency can be used. For example, a composite oxide having a characteristic composition including Bi, Sr, Te, Co, and O as constituent elements is used. can do. In particular, in the present system 100, the exhaust E flowing through the exhaust passage 5 when the fuel G is burned in the burner section 6 is very high, 800 ° C. or more, and therefore heat resistance that can operate even at such a temperature. It is desirable to use the thermoelectric conversion material 21 made of a complex oxide having a specific composition and a specific structure that has a specific structure.
Moreover, since the thermoelectric conversion material 21 having such heat resistance is coated on the outer surface of the evaporation pipe 11, even when the temperature of the exhaust E flowing through the exhaust passage 5 becomes very high, Thermal damage to the evaporator tube 11 is prevented.

In the exhaust passage 5, on the downstream side of the evaporation pipe 11, a heat transfer pipe 31 in which the air A supplied from the fan 32 circulates is arranged in a meandering manner in the exhaust passage 5, and the air A supplied to the SOFC 1. Is provided with an air preheating unit 30 that heats the air by heat exchange with the exhaust E.
The air preheating unit 30 heats the air A supplied to the SOFC 1 with the exhaust E having a temperature of about 160 ° C. after the air A is recovered for steam generation by the steam generation unit 10 and power generation by the thermoelectric generation unit 21. Since the heat is generated by the exchange, the heat of the exhaust E is used for preheating the air A supplied to the SOFC 1, thereby further improving the energy efficiency.

The steam passage 15 through which the steam S generated by the steam generator 10 flows is provided with a steam heater 40 that is operated by the power generated by the thermoelectric generator 20 and superheats the steam S. Specifically, the steam heater unit 40 is configured by a ribbon heater that is wound around a pipe constituting the steam flow path 15.
Therefore, the generated electric power of the thermoelectric generator 20 is supplied as the operating electric power of the steam heater 40, and the steam S is heated by the steam heater 40, and the high-temperature superheated steam S that can be effectively used becomes the steam consumer X Will be supplied.
In addition to the power generated by the thermoelectric generator 20, surplus power that has not been consumed by the power consuming unit 80 among the generated power of the SOFC 1 is supplied to the steam heater 40 as operating power, and the superheated steam S You may comprise so that it may heat up to still higher temperature.

Further, the latent heat storage material 16 having a melting point higher than the boiling point of the water W is connected to the steam flow path 15, for example, with the steam S flowing through the steam flow path 15 while covering the outside of the pipe constituting the steam flow path 15. It is provided in a state where heat can be exchanged between them. Therefore, even when the temperature and amount of the water vapor S flowing out from the gas-liquid separator 12 to the steam channel 15 fluctuate, the latent heat storage material 16 provided in the steam channel 15 is in the vicinity of the melting point higher than the boiling point of the water W. By storing and releasing the latent heat at the temperature, the temperature and amount of the water vapor S supplied to the steam consuming part X through the steam channel 15 can be stabilized.
As the latent heat storage material 16 can be appropriately using a known phase change material, such as MgCl ₂ or a saccharide having a melting point of about 120 ° C. to 190 ° C..

Next, description is added about the steam consumption part X which consumes the water vapor | steam S which generate | occur | produced in the steam generation part 10 mentioned above.
As the steam consumption section X, a steam turbine power generation section 50 capable of generating electric power by rotationally driving a steam turbine 51 connected to a generator 52 by steam S is provided.
That is, the steam S generated by the steam generator 10 is supplied to the steam turbine power generator 50 as the steam consumer X to generate power. The generated power of the steam turbine power generation unit 50 may be supplied to a power consumption unit different from the power consumption unit 80. However, in the system 100 of the present invention, the power consumption unit 80 is combined with the generated power of the SOFC1. Has been supplied to.
Therefore, fluctuations in the power generation output of the SOFC 1 are suppressed even when the power load in the power consumption unit 80 is large.

Furthermore, the power load meter 82 (an example of the power load detection means) for detecting the power load in the power consumption unit 80 and the steam supply amount to the steam turbine power generation unit 50 are adjusted, and the power generation output of the steam turbine power generation unit 50 is adjusted. An adjustable adjustment valve 53 (an example of a steam power generation output adjusting means) is provided, and the control device 70 functions as a steam power generation output control means for controlling the adjustment valve 53 based on the detection result of the power load meter 82. Is configured to do.
Therefore, the power generation output of the steam turbine power generation unit 50 is appropriate for the power load in the power consumption unit 80. That is, for example, even when the power load of the power consumption unit 80 fluctuates, the generated power to be supplied to the power consumption unit 80 by the SOFC 1 is stabilized by changing the power generation output of the steam turbine power generation unit 50 according to the fluctuation. As a result, fluctuations in the power generation output of the SOFC 1 are suppressed.

  In a general home, a relatively large heat and power demand is generated in the time zone from 18:00 to 24:00. In view of this, the fuel G is burned by the burner unit 6 during this time period, and electric power of about 0.3 kW is generated in the thermoelectric generator 20 and the steam turbine generator 50 to generate steam S and hot water HW. 8kW heat recovery can cover large heat and power demands. For example, the capacity of the hot water storage tank 70 for storing hot water HW in preparation for large heat demand is reduced, and heat dissipation loss in the hot water storage tank 70 is reduced. can do.

  The steam consumption unit X other than the steam turbine power generation unit 50 will not be described in detail, but for example, cooking is performed by supplying the steam S into a chamber in which the cooking object is stored to cook the cooking object. Equipment, portable cleaning equipment for injecting water vapor S for cleaning, humidifying equipment for supplying water vapor S to the room to humidify the room, and injecting water vapor S into the tableware storage part for storing tableware Steam in all forms, such as dishwashing equipment for washing dishes, a hot water generator for producing water by mixing steam S with water, and a cooking heater for spraying steam S on the food to heat the food A utilization device 66 can be employed.

For example, examples of the humidifying device of the steam using device 66 include a steam sauna nozzle 67 that injects steam S into the bathroom and uses the bathroom as a steam sauna.
In addition, the steam sauna nozzle 67 is supplied with steam S along with the flow rate adjustment by the adjustment valve 68, and with hot water HW stored in a hot water storage tank 70, which will be described later, with flow rate adjustment through the adjustment valve 69. Thus, the mist that has been mixed with the steam S and the hot water HW and has an appropriate temperature can be sprayed.

  Next, in the system 100 of the present invention, generation of hot water HW used for heating hot medium water, which is a heat source, such as for hot water supply to the bathtub 64 and the hot water supply unit 65, and for an air conditioner 62 such as a heating device and a desiccant type dehumidifying device Add a description of the method.

  In the exhaust passage 5, a heat transfer pipe 36 in which water W flows is arranged in a meandering manner in the exhaust passage 5 on the downstream side of the evaporation pipe 11 and further on the downstream side of the air preheating unit 30. A first heat exchanging unit 35 for heating W by heat exchange with the exhaust E is provided. And by heating the water W by this 1st heat exchange part 35, about 40 degreeC warm water can be obtained.

Furthermore, the 2nd heat exchange part 55 which heats the water W heated by the 1st heat exchange part 35 by heat exchange with the water vapor | steam S discharged | emitted from the steam turbine electric power generation part 50 is provided.
The second heat exchanging unit 55 converts the steam S discharged from the steam turbine power generation unit 50 into the heat transfer pipe 56 in which the water W supplied from the first heat exchanging unit 35 circulates in the condenser 57. The water W is heated to a high temperature of, for example, about 90 ° C. by the sensible heat and latent heat of the water vapor S.

In the condenser 57, another heat transfer pipe 58 is disposed along the heat transfer pipe 53 of the second heat exchanging portion 55, and in the heat transfer pipe 58, an air conditioner is provided by a circulation pump 61. Heat transfer water circulating through the circulation circuit 60 circulates between the heat transfer water and 62.
That is, the heat transfer water heated through circulation in the heat transfer pipe 58 is supplied to the air conditioner 62, and on the other hand, the heat transfer water after radiating heat from the air conditioner 62 is returned to the heat transfer pipe 58 again. A heat source can be supplied to the device 62 to perform operations such as heating and dehumidification.

  In addition, the air conditioner 62 is configured as a desiccant-type dehumidifying device, and dehumidification is performed using the heat supplied by the heat transfer water, thereby reducing power demand compared to the case where dehumidification is performed using electric power. While reducing the heat demand, it is possible to equalize the consumption ratio of electric power and heat.

  Further, the water vapor S is condensed in the condenser 57 to become water W, which is added to the water W supplied from the pure water generator 3 to the gas-liquid separator 12 and reused.

  The hot water HW heated to about 90 ° C. by the second heat exchanging unit 55 is configured to be stored in the hot water storage tank 70 at one end and to be supplied to the bathtub 64 and the hot water supply unit 65.

The hot water storage tank 70 is configured to store hot water at a temperature such as a completely mixed type that stores hot water at approximately the same temperature in the vertical direction, or hot water at the upper part and hot water at the lower part in the vertical direction. It is configured as a temperature stratification type that stores in a form that forms a stratification.
Further, when the hot water storage tank 70 is configured as a temperature stratification type, although not shown in the figure, the water pressure is constantly applied to the hot water storage tank 70 by supplying low temperature water W from the water supply to the bottom of the hot water storage tank 70. Further, after the low-temperature water at the bottom of the hot water storage tank 70 is heated to an appropriate temperature or higher by heat exchange with the cooling water of the SOFC 1, the hot water storage tank 70 is returned to the uppermost part of the hot water storage tank 70. Hot water can be stored in a form that forms temperature stratification.

〔Example〕
Next, an embodiment of the system 100 of the present invention will be described.
For example, when the rated power output of the SOFC 1 is 1 kW, the temperature of the exhaust E discharged from the SOFC 1 is about 380 ° C. Further, the fuel G supplied to the SOFC 1 is supplied with approximately the same amount of fuel G as the burner section 6. In the steam generation unit 10, the steam S having a flow rate of about 4 kg / h, a pressure of about 0.7 MPa, and a temperature of 180 ° C. can be generated. At the same time, the thermoelectric generator 20 can expect about 0.03 kW of power recovery for about 2.67 kW of input heat. Furthermore, in the steam turbine power generation unit 50, if the heat insulation efficiency is 80% and the condensate temperature is 85 ° C., power recovery of about 0.3 kW can be expected.
When the supply amounts of city gas as the fuel G to the SOFC 1 and the burner unit 6 are 0.197 Nm ³ / h and 0.2 Nm ³ / h, respectively, the input heat amount of the burner unit 6 is a high calorific value. On the other hand, since the increase in the amount of recovered heat due to the generation of the steam S or the hot water HW is 2.09 kW, the energy efficiency by reheating (repowering) the exhaust E by the burner unit 6 in the system 100 of the present invention. Is (0.3 + 0.03) / (2.50-2.09) × 100 = 80.5%.
The amount of heat recovered by the air preheating unit 30 is about 0.2 kW regardless of whether or not the fuel G is burned in the burner unit 6.

[Another embodiment]
(1) In the above embodiment, the present invention system 100 configured to supply electric power and heat to a place such as one home has been described. However, as shown in FIG. It is also possible to adopt a form in which electric power and heat are distributed and supplied to each of the plurality of residences 90 provided in.
Specifically, in the system 200 of the present invention shown in FIG. 2, the power generated by the SOFC 1, the thermoelectric generator 20 and the steam turbine generator 50, the hot water HW generated by the second heat exchanger 55, and steam generation The steam S generated in the unit 10 is distributed and supplied to the power consuming unit 80, the hot water storage tank 70, and the steam consuming unit X installed individually in each residence 90.

  Further, the hot water HW heated to about 90 ° C. by the second heat exchange unit 55 goes around each residence 90 from the downstream side of the second heat exchange unit 55 using the circulation pump 83 as a power source. 55 is configured to constantly circulate through a hot water circulation path 84 reaching the upstream side of 55. Then, the hot water HW consumed in each residence 90 is supplied from the hot water circulation path 84 to the hot water storage tank 70.

(2) In the above embodiment, the water generation unit 10 is configured to heat the water W as a liquid in order to generate the water vapor S as the vapor in the vapor generation unit 10. The liquid may be heated so that the vapor of the liquid is generated as a drive source of the steam turbine power generation unit 50, for example.

(3) In the above embodiment, the steam generation unit 10 is configured to take out the water vapor S from above in the gas-liquid separator 12, but separately, such a gas-liquid separator 12 is omitted, and the steam pipe Alternatively, the steam S may be taken out directly from the heat generator 11.
Furthermore, in the above embodiment, when the steam generating unit 10 is configured to take out the water vapor S from above in the gas-liquid separator 12, the latent heat storage material 13 is provided in the gas-liquid separator 12, Separately, such a latent heat storage material 13 may be changed to another heat storage material or omitted.

(4) In the above embodiment, the air preheating unit 30 for heating the air A supplied to the SOFC 1 by heat exchange with the exhaust E is provided on the downstream side of the evaporation pipe 11 in the exhaust passage 5. Such an air preheating unit 30 may be omitted, and for example, in another form, the heat of the exhaust E discharged to the downstream side of the steam pipe 11 may be recovered.

(5) In the above embodiment, the steam turbine power generation unit 50 is provided as the steam consumption unit X that consumes the generated water vapor S of the steam generation unit 10. However, such a steam turbine power generation unit 50 is omitted separately. It doesn't matter.
Furthermore, in the above-described embodiment, when the steam turbine power generation unit 50 is provided, the adjustment valve 53 is controlled based on the detection result of the power load meter 82 as described above, and the power generation output of the steam turbine power generation unit 50 is consumed. Although the structure for making it suitable for the electric power load in the unit 80 is adopted, such a structure is omitted separately, for example, the power generation output of the steam power generation unit 50 is kept constant regardless of the electric power load. The amount of water vapor S supplied from the steam generation unit 10 may be arbitrarily changed following the supply amount.

(6) In the above embodiment, the steam flow path 15 is provided with the steam heater section 40 that is operated by the generated power of the thermoelectric generator 20 and superheats the generated steam S. However, such a steam heater section 40 is omitted separately. It doesn't matter.
Moreover, in the said embodiment, when the steam flow path 15 is provided with the steam heater part 40, the latent heat storage material 16 is further provided in the steam flow path 15, and is supplied to the steam consumption part X through the steam flow path 15. However, the latent heat storage material 16 may be replaced with another heat storage material or may be omitted.

(7) In the above embodiment, the first heat exchanging unit 35 heats the water W by heat exchange with the exhaust E discharged to the downstream side of the evaporation pipe 11 of the exhaust passage 5, and the second heat exchanging unit 55, the water W heated by the first heat exchange unit 35 is heated by heat exchange with the steam S discharged from the steam turbine power generation unit 50 to generate high-temperature hot water HW. In the case where one of the first heat exchange part 35 and the second heat exchange part 55 is omitted and the water W is heated only by the other, or when it is not necessary to heat the water W, the first heat exchange part 35 and the second heat exchange part 55 are omitted. Both the heat exchange part 35 and the second heat exchange part 55 may be omitted.

  The solid oxide fuel cell system according to the present invention is a solid oxide fuel cell system that generates electric power by a solid oxide fuel cell using a solid oxide as an electrolyte and simultaneously uses exhaust heat obtained. As a solid oxide fuel cell system that achieves excellent energy efficiency by rationally and effectively using the exhaust heat of solid oxide fuel cells while suppressing thermal damage caused by high-temperature exhaust heat It can be used effectively.

Schematic configuration diagram of a solid oxide fuel cell system according to the present invention Schematic configuration diagram of a solid oxide fuel cell system of another embodiment

Explanation of symbols

1: SOFC (solid oxide fuel cell)
2: reforming unit 3: pure water generating unit 5: exhaust passage 6: burner unit 10: steam generating unit 12: gas-liquid separator 15: steam flow path 13, 16: latent heat storage material 20: thermoelectric generator 21: thermoelectric Conversion material 30: Air preheating unit 35: First heat exchange unit 40: Steam heater unit 50: Steam turbine power generation unit 55: Second heat exchange unit 62: Air conditioner 70: Control device (steam power generation output control means)
80: Power consumption unit 100, 200: System of the present invention (solid oxide fuel cell system)
HW: Hot water X: Steam consumption part W: Water (liquid)
S: Water vapor (steam)
G: Fuel E: Exhaust

Claims (7)

A solid oxide fuel cell system that generates power using a solid oxide fuel cell that uses a solid oxide as an electrolyte, and that uses exhaust heat obtained at the same time,
A burner unit capable of mixing and combusting fuel with the exhaust gas discharged from the solid oxide fuel cell into the exhaust passage, and a liquid is supplied to an evaporation pipe disposed in the exhaust passage and supplied to the vapor consuming unit. A solid oxide fuel comprising: a steam generating section that generates steam; and a thermoelectric generation section that provides a thermoelectric conversion material on the outer surface of the evaporation pipe and generates power using a temperature difference between the exhaust and the evaporation pipe Battery system.   2. The solid oxide fuel according to claim 1, further comprising an air preheating unit that heats the air supplied to the solid oxide fuel cell by heat exchange with the exhaust downstream of the evaporation pipe in the exhaust passage. Battery system. As a steam consumption unit that consumes the generated steam of the steam generation unit, a steam turbine power generation unit capable of generating electric power by rotationally driving a steam turbine with the generated steam,
A power load detecting means for detecting a power load in a power consuming unit to which the generated power of the solid oxide fuel cell and the steam turbine power generating unit is supplied;
Adjusting a steam supply amount to the steam turbine power generation unit, and adjusting a power generation output of the steam turbine power generation unit;
The solid oxide fuel cell system according to claim 1, further comprising: a steam power generation output control unit that controls the steam power generation output adjustment unit based on a detection result of the power load detection unit. A first heat exchange section for heating hot water by heat exchange with the exhaust downstream of the evaporation pipe in the exhaust passage;
4. The solid oxide fuel cell according to claim 3, further comprising: a second heat exchange unit that heats hot water heated by the first heat exchange unit by heat exchange with steam discharged from the steam turbine power generation unit. 5. system. The vapor generating unit has a gas-liquid separator that is disposed on a side of the evaporation pipe and is connected to a lower end and an upper end of the evaporation pipe to supply liquid therein, Configured to extract steam from above, and
The latent heat storage material having a melting point higher than the boiling point of the liquid is provided in the gas-liquid separator in a state in which heat can be exchanged with the liquid in the gas-liquid separator. 5. The solid oxide fuel cell system according to any one of 4 above. A steam passage through which the generated steam of the steam generating section circulates is provided with a steam heater section that operates by the generated power of the thermoelectric generator section and superheats the generated steam;
The latent heat storage material having a melting point higher than the boiling point of the liquid is provided in the steam channel in a state in which heat can be exchanged with the steam in the steam channel. A solid oxide fuel cell system according to claim 1. Purifying pure water to produce pure water by purifying tap water, and steam reforming fuel with steam generated by heating the pure water to generate hydrogen to be supplied to the solid oxide fuel cell And a reforming section that
The steam generation unit is configured to generate water vapor by supplying the pure water supplied from the pure water generation unit as the liquid to the evaporation pipe. Solid oxide fuel cell system.

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