JP4927324B2 - Fuel cell system - Google Patents

Description

  The present invention relates to a fuel cell system that uses exhaust energy such as high-temperature combustion exhaust gas or fuel electrode exhaust gas and air electrode exhaust gas discharged from a fuel cell unit by using a heat exhaust heat exchanger, and more particularly, a housing complex. In a system in which fuel supply such as reformed gas is supplied from a centralized fuel gas supply facility to fuel cell units distributed and installed as residential and commercial power generation facilities for home and business use, The present invention relates to a wide-area type fuel cell system that can preferably use exhaust heat.

  In recent years, fuel cell systems such as polymer electrolyte fuel cells (PEFC) and solid oxide fuel cells (SOFC) are being introduced as power and heat supply systems for homes and businesses. Such a fuel cell system is a system that generates electricity and hot water using city gas, LPG, kerosene, or the like as fuel, and the generated electricity is used as electric power for electric equipment. Moreover, hot water generated using the exhaust heat of the fuel cell is stored in a hot water storage tank and supplied to an oil supply system in a consumer. Thus, the fuel cell system has a function of supplying both electricity and heat by a single unit. Currently, models with power generation capacities of 500 W to 1 kW for household fuel cells and 3 to 5 kW and 30 kW class power generation capacities for commercial fuel cells are being developed.

  FIG. 12 is a block diagram showing a configuration example of a PEFC system 800 that is expected as a household or commercial fuel cell. This system 800 generally introduces a fuel gas G such as city gas into the reformer 810 to purify the reformed gas and send it to the PEFC battery stack 830 to perform a power generation operation as well as an exhaust heat recovery unit. At 850, low-temperature water is taken out. More specifically, the odorant contained in the fuel gas G is first removed by the desulfurizer 801, the fuel gas G is preheated by the heat exchanger 802, mixed with the steam S, and then sent to the reformer 810. be introduced. The reformer 810 is heated by the burner 810a and is maintained at about 800 ° C., and the fuel gas G is converted into a reformed gas containing hydrogen as a main component by the action of the catalyst. This reformed gas is guided to the carbon monoxide converter 822 by lowering the temperature in the heat exchanger 821, and the carbon monoxide component contained in the gas is converted into hydrogen and carbon dioxide, followed by carbon monoxide selection. In the oxidizer 823, the residual carbon monoxide concentration in the gas is reduced to about 10 ppm. Thereafter, the reformed gas is introduced into the fuel electrode 831 of the battery stack 830 through the humidifier 824. The hydrogen component is ionized in the fuel electrode 831, passes through the electrolyte 833, and generates a chemical reaction with oxygen in the air electrode 832 by the air blower 835 to generate electric power and generate water.

  The electric power generated in the battery stack 830 is converted from direct current DC to alternating current AC by the inverter 840 and supplied to home and commercial power equipment. On the other hand, the battery stack 830 generates heat due to a chemical reaction between hydrogen and oxygen, but this heat (exhaust heat) is taken out by the exhaust heat recovery unit 850 to generate low-temperature water. That is, the battery cooling water CW3 is circulated through the circulation system including the radiator 851 and the pump 852 to the battery cooling plate 834 provided in the battery stack 830, and the battery stack 830 is maintained at a constant temperature of about 80 ° C. and heated. Is taken out. The heated battery cooling water CW3 exchanges heat with tap water in the heat exchanger 853 and is cooled to about 30 to 40 ° C., whereby low temperature water of about 60 ° C. is obtained. This hot water is stored in a hot water tank 854, and is used for hot water supply to a kitchen, a washroom, and a bath as needed.

  In addition to this, the fuel electrode exhaust gas G1 discharged from the fuel electrode 831 of the battery stack 830 and the air electrode exhaust air A1 discharged from the air electrode 832 are guided to the reformer burner 810a and burned to be reformed. It is used as a heat source. Thus, in the PEFC system 800, the generation of low-temperature water using the exhaust heat of the battery stack 830 and the utilization of the fuel electrode exhaust gas G1 and the air electrode exhaust air A1 as the heat source of the reformer 810 High efficiency is achieved.

  FIG. 13 is a block diagram illustrating a configuration example of an SOFC system 900 that is a representative of a high-temperature fuel cell. Also in this system 900, the fuel gas G such as city gas is introduced into the reformer 910 via the desulfurizer 901 and the preheater 902, and the fuel gas G is reformed mainly containing hydrogen in the reformer 910. It is the same as the PEFC system 800 described above in that it is converted to a quality gas. However, since the SOFC battery stack 930 can also use a carbon monoxide component as a fuel, the reformed gas is introduced as it is into the fuel electrode 931 of the battery stack 930 maintained at about 700 to 1000 ° C. Most of the hydrogen component (and carbon monoxide component) in the introduced reformed gas reacts with oxygen ions sent from the air electrode 932 at the fuel electrode 931 to generate electricity. Air is introduced into the air electrode 932 from an air blower 935, and oxygen in the air is taken in and ionized. Such oxygen ions are transferred to the fuel electrode 931 through the electrolyte 933, and chemically react with the hydrogen component (and the carbon monoxide component) to generate electricity. The generated power is converted from direct current DC to alternating current AC by an inverter 940 and supplied to household and commercial power equipment.

  Generally, the hydrogen utilization rate at the fuel electrode 931 is 70 to 80%, and the remainder is discharged as surplus (fuel electrode exhaust gas). Further, the oxygen utilization rate in the air at the air electrode 932 is 50 to 60%, and the remainder is discharged as surplus (air electrode exhaust air). In order to utilize such surplus energy, the fuel electrode exhaust gas and the air electrode exhaust air are introduced into the combustion chamber 934 disposed on the outlet side of the battery stack 930 and burned. The heat generated by the combustion is used for heat retention of the battery stack 310 and is recovered by the heat exchangers 951 and 952. That is, the high-temperature combustion exhaust gas EG generated by the combustion in the combustion chamber 934 generates steam or high-temperature water HW of about 90 ° C. in the high-temperature water heat exchanger 951, and low-temperature water LW of about 60 ° C. in the low-temperature water heat exchanger 952. Each is manufactured. Such high-temperature water HW and low-temperature water LW are widely used for business use or hot water supply. A part of the high-temperature combustion exhaust gas EG is also sent to the reformer 910 and used as a heat source for reforming.

It is also known to use steam or high-temperature water produced by the above-described high-temperature water heat exchanger 951 as a heat retention heat source for a so-called 24-hour bath. For example, Patent Document 1 discloses a fuel cell system that maintains the temperature of hot water stored in a bathtub by circulating cooling water that has been heated to cool the battery stack in the bathtub. Has been.
JP 2003-51316 A

  As described above, the fuel cell system generates electricity and heat at the same time, and it is possible to increase the economy by effectively using both. However, regarding the utilization of the exhaust heat from the fuel cell, the exhaust heat may not be sufficiently utilized depending on a known system. That is, since the SOFC system 900 can generate steam or high-temperature water of about 90 ° C. using exhaust heat as described above, it can be used for cooling and heating in an absorption refrigerator, for example. On the other hand, since the PEFC system 800 can produce only low-temperature water of about 60 ° C. as described above, there is a problem that it can be used only for hot water supply and has a relatively low utility value. In addition, even in a high temperature fuel cell such as the SOFC system 900, the exhaust heat temperature level discharged by a small-sized one used for home use becomes low and it becomes difficult to obtain steam, so the economic efficiency is lowered. There is a case.

  By the way, when the fuel cell system is individually installed in a small-sized consumer existing in a certain local area such as in each household of an apartment house, a multipurpose commercial building, or a factory facility, fluctuations in heat and power load of individual consumers are Since they are mixed, there are merits such as a reduction in the amount of seasonal fluctuation of the load and a reduction in the maximum / minimum power demand width. For this reason, when introducing a fuel cell system to such an application, relatively small fuel cell units that do not have a reformer are dispersed and installed in each consumer, and the reformed gas is a centralized type common to each consumer. It is desirable that the fuel cell system is a centralized reforming fuel cell system in which the reformed gas is supplied to the fuel cell units refined by the fuel reformed gas supply device and dispersedly arranged by gas piping.

  When such a concentrated reforming fuel cell system is adopted, a problem of effective utilization of unused hydrogen gas and oxygen gas (exhaust energy) discharged from the battery stack emerges as a new issue. That is, not all of the reformed gas supplied to each fuel cell unit is consumed in the battery stack, and about 20% of unused hydrogen gas (fuel electrode exhaust gas) is air from the fuel electrode of the battery stack. About 50% of unused oxygen gas (air electrode exhaust air) is discharged from the pole. These can be used by being burned by the reformer burner 810a in the above-described general PEFC system 800, but such a utilization mode cannot be obtained if a centralized reforming type configuration is adopted. Furthermore, since the SOFC system 900 cannot be used to use a part of the high-temperature combustion exhaust gas EG discharged from the combustion chamber 934 as a heat source for reforming, it is possible to effectively use surplus exhaust heat corresponding to the heat source for reforming. It becomes a problem.

  Accordingly, it is an object of the present invention to provide a more economical fuel cell system by effectively utilizing exhaust heat and energy exhausted from a battery stack, and in particular, individually like a intensive reforming fuel cell system. It is an object of the present invention to provide a system that can efficiently use waste energy efficiently in a fuel cell system including a fuel cell unit of a type that does not include a reformer.

A fuel cell system according to claim 1 of the present invention is a fuel cell system in which a fuel cell unit that introduces fuel gas into a cell stack to generate electricity and an exhaust heat exchanger having a heating unit are combined. And having a waste energy utilization mechanism for using the waste energy discharged from the battery stack of the fuel cell unit as a heating source of the heating unit in the waste heat heat exchanger, An exhaust heat exchanger burner is provided as a heating source of the heating unit, and a bypass piping system is provided in a piping system for the fuel gas introduced into the battery stack, and the bypass piping system includes the exhaust heat exchanger burner. It is characterized by being connected to .

  According to this configuration, the heating unit in the exhaust heat exchanger is heated by the exhaust energy utilization mechanism that uses the exhaust energy discharged from the battery stack (for example, combustion of the fuel electrode exhaust gas and the air electrode exhaust air) The exhaust heat exchanger is used to provide heat for heat exchange, and the high-temperature combustion exhaust gas is used to supply heat to the exhaust heat exchanger. Can be improved. In other words, the exhaust heat heat exchanger is heated by the exhaust energy itself discharged from the battery stack, rather than using the steam or high-temperature water that is generated by the exhaust heat of the battery stack. Even when using a fuel cell unit that is difficult to produce high-temperature water, it is possible to easily extract the exhaust heat (exhaust energy) with a combined exhaust heat exchanger and make effective use of it. become able to.

The exhaust heat exchanger includes a waste heat exchanger burner as a heating source of the heating unit, and a bypass piping system is provided in a fuel gas piping system introduced into the battery stack. Since it is configured to be connected to the exhaust heat exchanger burner, when only the exhaust energy discharged from the battery stack causes a shortage in the amount of heating heat of the exhaust heat exchanger, a bypass piping system is provided. By operating the exhaust heat exchanger burner with the fuel gas (reformed gas) supplied via it, heat can be stably given to the exhaust heat exchanger.

A wide-area fuel cell system according to a second aspect of the present invention includes a fuel gas supply facility that is connected to a commercial gas supply system and purifies a fuel gas that serves as a drive source for the fuel cell, and a plurality of fuel cell systems that exist in a predetermined local area. Each fuel cell unit is a wide-area type fuel cell system comprising individual fuel cell systems dispersedly arranged in each consumer, wherein the fuel gas supply facility is capable of supplying fuel gas to each consumer. The individual fuel cell system includes a fuel cell unit that introduces the fuel gas into a cell stack to generate electricity, and an exhaust heat exchanger that includes a heating unit. Exhaust energy to be used as a heating source of a heating unit in the exhaust heat exchanger, wherein the exhaust energy discharged from the battery stack of the fuel cell unit is combined. Have a ghee use mechanism, as a heating source of the heating unit in the exhaust heat exchanger comprises a waste heat exchanger burner, the bypass pipe system is provided in the piping system of the fuel gas to be introduced into the cell stack The bypass piping system is connected to the exhaust heat exchanger burner .

  According to this configuration, by applying a centralized fuel gas supply facility common to each fuel cell unit, each fuel cell unit does not require a reformer unit, and the device configuration can be simplified and reduced in size. Since the reformed gas can always be supplied, the start-up time is shortened compared to a system having an individual reformer, and the fuel cell unit can be operated efficiently. In addition to this, the fuel cell unit distributed to each consumer will not be equipped with a reformer, but the waste energy used in the reformer is distributed to the consumer. Since it can be used in the exhaust heat exchanger provided in the individual fuel cell system, the economic efficiency of the system can be improved.

  Here, the difference between a general fuel cell system and a so-called concentrated reforming fuel cell system will be roughly described with reference to FIGS. 1 and 2. FIG. 1 is a block diagram showing a general fuel cell system. In this system, the fuel cell system unit 800 includes a fuel cell unit 801, a reformer 802 that supplies reformed gas to the fuel cell unit 801, a control unit 803 that controls these operations, and a fuel cell unit 801. The hot water storage tank 804 which produces | generates warm water using the waste heat of this. The electricity generated by the fuel cell unit 801 is used by an electric device 811 in a consumer, and the hot water in the hot water storage tank 804 is used by a heat demand device 812 such as a hot water supply facility. In such a system, raw fuel such as city gas is introduced into the reformer 802, and the reformed gas is purified by the reformer 802 and supplied to the fuel cell unit 801. That is, the fuel cell system unit 800 provided individually for each consumer is provided with the reformer 802, and the reformed gas is purified for each consumer.

  The present invention is naturally applicable to such a general fuel cell system. However, in such a system configuration, it is difficult to operate following a load fluctuation of a consumer (especially a small consumer). Fig.11 (a) has shown the electric power load fluctuation | variation state which measured the electrical load in the single-family house in a second unit. As shown in the figure, a large electric power load fluctuation is constantly generated in a detached house, and in this measurement example, the minimum load is about 300 W, the maximum load is about 3000 W, and there is a fluctuation of up to 10 times. However, the load follow-up performance of a household fuel cell having a reformer is limited to about 10% / min, and it is difficult to operate following the instantaneous load fluctuation as described above.

  On the other hand, FIG.11 (b) is the electric power load fluctuation state measured in the whole apartment house. In such an apartment house, the load change curve is smoothed compared to a detached house. In this measurement example, the minimum load is about 8000 W, the maximum load is about 30000 W, and the fluctuation range is about 3.8 times. It is settled. This is because various households gather in the housing complex, so that the power and heat load are leveled as a whole. Therefore, even when fuel cells are introduced into ordinary homes, fuel cells are distributed in each household and distributed to each consumer rather than introducing a fuel cell system with a reformer independently for each household. A centralized reforming fuel cell system that enables individual consumption of electricity and heat, while supplying fuel gas to each fuel cell from a centralized fuel supply system, allowing operation control over the entire local area It is desirable to build

  FIG. 2 is a block diagram showing an example of such a concentrated reforming fuel cell system. Fuel cell units 700a and 700b are individually provided for (small) consumers A and B existing in a predetermined local area (for example, a group of detached houses in an apartment house or a certain area). However, for example, reformed gas or the like is supplied to these fuel cell units 700a and 700b from a common centralized fuel gas supply facility (centralized reformer 10). That is, the fuel cell units 700a and 700b are composed of the fuel cell units 701a and 701b, the control units 703a and 703b, and the hot water storage tanks 704a and 704b, and are not provided with individual reformers, and under the control of the control unit 10M. The reformed gas is purified from the raw fuel by the centralized reformer 10 and supplied to the consumers A and B. And the electric power and heat which generate | occur | produced in each fuel cell unit 700a, 700b are consumed by the electric equipment 711a, 711b and heat demand equipment 712a, 712b with which each consumer A, B is equipped.

  For heat use by small consumers such as households, it is possible to eliminate the need for heat supply piping by installing fuel cell equipment in the consumer, which is the heat demand point, and extracting heat. It is the most economical from the viewpoint that heat loss can be suppressed. On the other hand, it is more practical to install a fuel gas supply apparatus having a large scale merit, high efficiency, and a centralized type that has the capacity for small fuel gas fluctuations. In view of such points, in the present invention, small fuel cell units 700a and 700b having no reformer are distributed and installed at each customer site, while the supply of reformed gas is a concentrated fuel gas supply. The system configuration is such that the apparatus (central reforming apparatus 10) collectively supplies the power load (electric devices 711a and 711b) and the heat load (heat demand devices 712a and 712b) independently for each consumer. Is.

  According to such a configuration, even if each small fuel cell unit 700a, 700b is individually operated, the fuel gas supply amount as a whole of several, tens, hundreds of small fuel cell units is smoothed ( In other words, sudden load fluctuation does not occur as a whole), so that the aggregated fuel gas supply apparatus can be operated gently and can be economically operated. Therefore, such a concentrated reforming fuel cell system is a system to which the present invention is preferably applied. The fuel cell unit is not limited to one type of fuel cell, but a plurality of units having different power generation capacity, power generation efficiency, exhaust heat efficiency, start-up time, etc., and different fuel cells such as solid polymer type and solid electrolyte type A combination of standard units can also be used.

In the above configuration , the fuel cell unit is a high-temperature fuel cell unit, and the exhaust energy utilization mechanism is heated in the exhaust heat exchanger by the high-temperature combustion exhaust gas discharged from the battery stack of the high-temperature fuel cell unit. part may be further provided with Ru constitute a mechanism for heating directly (claim 3). According to this configuration, in order to keep the battery stack of the high-temperature fuel cell unit warm, the high-temperature combustion exhaust gas discharged from the combustion chamber attached to the battery stack is guided to the heating unit of the exhaust heat exchanger, Heat is directly given to the exhaust heat exchanger by the high-temperature combustion exhaust gas.

In the above configuration , the fuel cell unit includes a low-temperature fuel cell unit, and the exhaust energy utilization mechanism converts the fuel electrode exhaust gas and the air electrode exhaust air discharged from the battery stack of the low-temperature fuel cell unit into the burner. It can be set as the structure sent to and combusted (Claim 4). According to this configuration, the fuel electrode exhaust gas and the air electrode exhaust air discharged from the battery stack are utilized as the fuel for the exhaust heat exchanger burner.

In the above configuration , the fuel cell unit is provided with a hot water storage tank for storing hot water, and the heating medium is circulated to transfer the heat given by the exhaust heat exchanger to the hot water in the hot water storage tank. It is desirable to have a configuration including a piping system. According to this configuration, the heat given to the exhaust heat exchanger is transferred to the hot water stored in the hot water storage tank to generate high-temperature water close to 90 ° C., which can be stored in the hot water storage tank. Become.

Further, in the above configuration , a hot water storage tank for storing hot water in the fuel cell unit and a bathtub provided with a bathtub water purification device are provided side by side, and the heat given by the exhaust heat exchanger is used for hot water in the hot water storage tank. And / or it is desirable to set it as the structure which comprises the temperature rising piping system for giving / receiving to the hot water in the said bathtub (Claim 6). According to this configuration, the heat given to the exhaust heat exchanger is transferred to the hot water stored in the hot water storage tank, and further to the hot water stored in the bathtub, 90 Hot water close to 0 ° C. can be generated and stored in the hot water tank, and can also be used to keep hot water in the bathtub provided with a bathtub water purification device typified by a so-called 24-hour bath.

In the above configuration , the hot water storage tank is separated into the high temperature water hot water tank and the low temperature water hot water tank, and the temperature raising piping system is piped through the high temperature water hot water tank and the low temperature water hot water tank. It is desirable that the heat medium in the piping system is configured to be circulated through the high-temperature water hot-water tank first and then through the low-temperature water hot-water tank after leaving the exhaust heat exchanger (claim). Item 7 ). According to this configuration, the heat obtained by the exhaust heat exchanger is sequentially used in cascade in the high-temperature water storage tank and the low-temperature water storage tank, and heat exchange can be performed efficiently. Become.

In the above configuration , the exhaust heat exchanger is provided with a water recovery device that recovers moisture contained in the exhaust gas from the high temperature combustion exhaust gas discharged from the battery stack or the combustion exhaust gas of the exhaust heat exchanger burner as drain water. (Claim 8 ). According to this configuration, when pure water generated in the fuel cell unit or water generated during the combustion reaction in the exhaust heat exchanger burner is drained in the exhaust heat exchanger, Can be recovered and used for various purposes.

  According to the fuel cell system of claim 1, since the exhaust heat itself is heated by the exhaust energy itself discharged from the battery stack, a fuel cell unit that is difficult to generate steam or high-temperature water by exhaust heat is provided. Even when used, the exhaust heat (exhaust energy) can be easily and effectively utilized. Therefore, even when a low-temperature fuel cell unit that can generate only low-temperature water for hot water supply is used, high-temperature water of about 90 ° C. can be generated using exhaust heat, and effective use of exhaust heat can be achieved. It becomes like this.

  According to the fuel cell system of claim 2, the individual fuel cell system is distributed and installed in each consumer, and the supply of fuel gas is supplied from a centralized fuel gas supply facility. As the fuel gas supply load change with a large level is leveled, it becomes possible to alleviate the influence of the load follow-up speed of the reformer, which is the biggest limiting factor of the load follow-up speed of the fuel cell system. Can greatly improve the operability. In addition, since the fuel gas is constantly supplied to the vicinity of the individual fuel cell system of each consumer, the fuel supply is immediately started to the fuel cell unit in each consumer if the supply valve is opened. Since the start-up time until the gas is reformed is shortened, for example, if the fuel cell unit is made of a polymer electrolyte fuel cell, quick load follow-up and immediate start-up are possible. As a result, the polymer electrolyte fuel cell unit can be frequently started and stopped, and can be stopped during midnight hours, and can also be stopped during the day when electricity or heat is not needed, reducing operational restrictions due to fuel cell system restrictions. Economical operation is possible. In addition to this, the waste energy used in the reformer can be used in the waste heat exchanger installed in the individual fuel cell systems distributed to the consumers. It is possible to make a complete system in terms of utilization of waste energy.

According to the fuel cell system of claims 1 and 2, the exhaust heat heat exchanger burner can be operated with the fuel gas (reformed gas) supplied via the bypass piping system. Thus, the load on the individual fuel cell system is not restricted, and the operation suitable for the heat demand can be executed.

According to the fuel cell system of claim 3, the high-temperature fuel cell unit further includes a mechanism in which the exhaust heat exchanger is directly heated by the high-temperature combustion exhaust gas discharged from the combustion chamber. In addition, a waste energy utilization mechanism can be constructed simply by attaching a piping path for guiding the high-temperature combustion exhaust gas from the combustion chamber to the waste heat exchanger, and the waste heat can be utilized more effectively with a simple configuration.

  According to the fuel cell system of claim 4, in the low-temperature fuel cell unit, the fuel electrode exhaust gas and the air electrode exhaust air discharged from the cell stack are utilized as the fuel for the exhaust heat exchanger burner serving as a heating source. Therefore, it is possible to construct a waste energy utilization mechanism by simply attaching a piping path for guiding the fuel electrode exhaust gas and the air electrode exhaust air from the discharge side of the battery stack to the exhaust heat exchanger burner. Waste heat can be used more effectively.

  According to the fuel cell system of claim 5, the heat given to the exhaust heat exchanger is transferred to the hot water stored in the hot water storage tank to generate high-temperature water close to 90 ° C., and this is stored in the hot water storage tank. Since it can be stored, it can be widely used for various types of hot water supply, and the availability of waste energy is greatly improved.

  According to the fuel cell system of claim 6, for example, a 24-hour bath is installed in the fuel cell power generation unit of each customer, and the hot water from the hot water storage tank storing the hot water is heated in the 24-hour bath. By using it as a source (heat source), it is possible to reduce electricity or gas that has conventionally been required for heat insulation. Therefore, the heat cost for keeping the 24-hour bath is reduced, and since the hot water is always provided in the 24-hour bath, there is no need for a hot water tank for bath water supply, and the hot water tank can be greatly reduced in size. In addition, a heating medium that circulates in the temperature raising piping system is first transferred through a high-temperature hot water tank to lower the temperature of the heating medium, and then a circulation route that is used for heat insulation through a bath for 24 hours. If it does so, a heat medium will be used in cascade and heat exchange can be performed efficiently.

According to the fuel cell system of claim 7 , the heating medium in the temperature raising piping system first transfers heat in the high temperature water hot water tank to raise the hot water tank temperature, and then enters the low temperature water hot water tank. Therefore, the heat medium heated by the exhaust heat exchanger can be used in cascade, and heat exchange can be performed efficiently. Moreover, the hot water of the high-temperature water storage hot water can be used as a heating source for an absorption refrigerator, for example, and can be used as heat for air conditioning for heating or cooling.

According to the fuel cell system of the eighth aspect, since the steam contained in the combustion exhaust gas is recovered as drain water by the water recovery device, it is possible to provide a system that can use the generated water without waste. In particular, the purity of the water produced in a system using polymer electrolyte fuel is very high, so it is used for humidifying battery cells, supplying battery cooling water, and supplying the remainder to a piping system that supplies water to a hot water tank. By doing so, the generated water can be used without waste. In addition, in a system using phosphoric acid type or high-temperature type fuel, pure water generated in the fuel cell unit can be used for beverages if water treatment is performed. The system can use the generated water without waste.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and can be implemented with appropriate modifications. In the following description, a wide-area fuel cell system (centralized reforming fuel) that supplies reformed gas and the like together with a centralized fuel gas supply facility to individual fuel cell systems arranged at a plurality of consumers. The battery system will be mainly described.

(First embodiment)
Before describing the present embodiment, a general power and gas supply system will be outlined. FIG. 3 is a block diagram showing a form of supplying power and gas to a typical detached house or apartment house. For the consumers A, B, E, and G, the polymer electrolyte fuel cell (PEFC) system 200a is used. For the consumers C and F, the solid oxide fuel cell (SOFC) system 300a is used. General gas appliances 600 (fuel cell power generation system not yet introduced) are arranged. For each consumer A to H, gas is individually supplied from a commercial gas supply source 101G via a commercial gas supply system (city gas piping) 101, and power is supplied from a commercial power supply source 110G to a commercial power supply system. 110 are supplied individually. That is, even if the consumers A to H have introduced the fuel cell systems 200a and 300a, they individually contract with the commercial gas supply company or the commercial power supply company, Gas and power are supplied through the power system 110.

  FIG. 4 is a block diagram showing a basic configuration of the intensive reforming fuel cell system S0 according to the present embodiment. Here, the consumers A to H are a plurality of small consumers existing in a predetermined local area, for example, each household of an apartment house, a single-family house in a predetermined area, or a small business consumer. While the consumers A, B, E, and G have the polymer electrolyte fuel cell (PEFC) units 200 and the consumers C and F, the solid oxide fuel cell (SOFC) units 300 are distributed. In addition, general gas appliances 600 (fuel cell power generation units are not introduced) are arranged at the consumers D and H. In addition, although illustration is abbreviate | omitted, the general gas appliance is also installed in the consumer in which the fuel cell units 200 and 300 are introduced.

  And about electric power, it is the form supplied separately to each consumer AH through the commercial power supply system 110 from the commercial power supply source 110G similarly to the normal supply form shown in FIG. Is configured to be individually supplied to each of the consumers A to H via the centralized fuel gas supply device 100 and the accumulator 120. That is, a source gas such as city gas is supplied from the commercial gas supply source 101G through the commercial gas supply system 101 to the centralized fuel gas supply apparatus 100, and the reformed gas is purified by the centralized fuel gas supply apparatus 100. The reformed gas is supplied to each consumer A to H via the accumulator 120. As the fuel used in the centralized fuel gas supply apparatus 100, petroleum-based liquid fuels such as kerosene, light oil, naphtha, and biogas may be used in addition to city gas. Furthermore, hydrogen gas produced by water electrolysis using sunlight and midnight power can be mixed and supplied together with these reformed gases.

  The accumulator 120 is installed to store a certain amount of reformed gas and maintain the reformed gas pressure at a constant level even when a sudden demand change of the reformed gas occurs. The reformed gas is supplied to the PEFC unit 200 and SOFC provided in each of the consumers A to H through a local pipeline 103 (which may be an existing city gas pipeline or the like) connected to the accumulator 120. It is supplied to the unit 300 and the general gas appliance 600. In addition, although the electric power used by each consumer AH is covered by the electric power generation by a fuel cell system, it is set as the structure purchased for every consumer from the commercial system 110 about the shortage.

  The fuel cell system of the present invention can be applied to a fuel cell system (PEFC unit 200a and SOFC unit 300a) included in each consumer as shown in FIG. However, as shown in FIG. 4, a centralized fuel gas supply device 100 that purifies fuel gas that is connected to the commercial gas supply system 101 and serves as a drive source for the fuel cell, and a plurality of demands existing in a predetermined local area. What is more suitable as the individual fuel cell system in a wide-area type fuel cell system (central reforming fuel cell system S0) including individual fuel cell systems (PEFC unit 200 and SOFC unit 300) distributed in a house It is. Hereinafter, embodiments of the individual fuel cell system will be described.

  FIG. 5 is a block diagram illustrating a configuration example of an individual fuel cell system S1 including a PEFC type fuel cell. This individual fuel cell system S1 has a system configuration in which a polymer electrolyte fuel cell (PEFC) unit 200 as a low-temperature fuel cell unit and an exhaust heat utilization unit 400 including an exhaust heat exchanger 41 are combined. Has been. The individual fuel cell system S <b> 1 uses a PEFC battery as a waste energy utilization mechanism for using the waste energy discharged from the PEFC battery stack 210 of the PEFC unit 200 as a heating source of the heating unit in the waste heat heat exchanger 41. The fuel electrode exhaust gas and the air electrode exhaust air discharged from the stack 210 are sent to the exhaust heat exchanger burner 41a for heating the heating part of the exhaust heat exchanger 41 and burned. Hereinafter, the configuration of each part will be described in detail.

  The PEFC unit 200 includes a PEFC battery stack 210, an air supply device 250 including a blower, an exhaust heat recovery unit 450, an inverter (not shown), and the like. The PEFC battery stack 210 includes a fuel electrode 221, an air electrode 222, an electrolyte 223, and a cooling plate 224. Note that the reformed gas RG previously reformed by the centralized fuel gas supply device 100 (see FIG. 4) is supplied to the PEFC battery stack 210 through the local piping 103 and the main piping 104. The desulfurizer and reformer are not provided separately.

  The exhaust heat utilization unit 400 includes an exhaust heat exchanger 41, a hot water storage tank 42, a water recovery tank (water recovery device) 43, a temperature raising piping system 44, and the like. The exhaust heat exchanger 41 gives heat (heat exchange) to a heat medium (for example, low-temperature water) flowing through the temperature raising piping system 44 in the heating unit. The exhaust heat exchanger 41 is provided with an exhaust heat exchanger burner 41a as a heating source, and the heat generated by the combustion of the exhaust heat exchanger burner 41a is converted into the heat source for heat exchange. It is utilized as.

  The hot water storage tank 42 stores hot water, and this hot water is used for a kitchen, a washroom, and a bath (heat demand equipment) in a consumer through an output piping 422 provided with a valve 422B. The hot water tank 42 also functions as a part of an exhaust heat recovery unit 450 described later. In the temperature raising piping system 44, a heat medium is circulated in order to transfer the heat given by the exhaust heat exchanger 41 to the hot water in the hot water storage tank 42. In this embodiment, the hot water stored in the hot water storage tank 42 can be circulated so as to return to the hot water storage tank 42 again via the heating section of the exhaust heat exchanger 41 by the temperature raising piping system 44. . That is, a part of the hot water stored in the hot water tank 42 is circulated in the temperature raising piping system 44 as a heat medium, and heat is exchanged by the exhaust heat exchanger 41 (the exhaust heat exchanger burner 41a is used as a heating unit). The heat exchanging part 411 of the arranged temperature raising piping system 44 is heated), and the temperature of the stored hot water in the hot water tank 42 is raised by returning the heated hot water to the hot water tank 42. Note that the temperature raising piping system 44 may be a closed piping line, and an appropriate heat medium may be circulated in the closed piping line.

  The combustion exhaust gas EG of the exhaust heat heat exchanger burner 41a is exhausted through the exhaust gas piping 411. Since the combustion exhaust gas EG also has corresponding heat, the exhaust gas pipe 411 may be routed through a low-temperature water heat exchanger or the like to recover the exhaust heat. Also, the combustion exhaust gas EG contains moisture generated in the PEFC battery stack 210, and water is also generated during the combustion reaction in the exhaust heat exchanger burner 41a, which is drained by heat exchange. Will do. The water recovery tank 43 recovers such drain water through a pipe 412 extending from the lower part of the exhaust heat exchanger 41.

  In such a configuration, hydrogen-rich reformed gas is introduced into the fuel electrode 221 from the centralized fuel gas supply device 100 via the accumulator 120 (and further via a humidifier or the like as necessary). . Thereafter, most of the hydrogen component in the introduced reformed gas is ionized at the fuel electrode 221, and the hydrogen ions are transferred to the air electrode 222 through the electrolyte 223. Air is introduced into the air electrode 222 from the air supply device 250 through the air piping 240, and oxygen in the air is taken in and ionized. The oxygen ions and hydrogen ions moved from the fuel electrode 221 chemically react to generate water and generate power. Since the electric power generated by such a chemical reaction is a direct current, it is converted into a direct current from a direct current by an inverter (not shown), and then supplied as a driving power source to various power devices existing in the consumer.

  In the PEFC battery stack 210, heat is generated because hydrogen and oxygen chemically react as described above. Therefore, although it is necessary to cool the PEFC battery stack 210 so as not to be overheated, the heat at the time of this cooling is recovered by the exhaust heat recovery unit 450 to generate hot water or the like, thereby effectively utilizing the heat. In the example illustrated in FIG. 5, the exhaust heat recovery unit 450 is configured by a heat exchanger 45, a radiator 46, a pump 47, a circulation path 48, and a hot water tank 42.

  A cooling plate 224 is attached to the PEFC battery stack 210, and a circulation path 48 and a radiator 46 for the cooling water CW passing through the cooling plate 224 are provided, and the cooling water CW is circulated in the circulation path 48 by the pump 47. By doing so, the battery stack is kept at a constant temperature (cooled). On the other hand, the circulation path 48 is a piping path that also passes through the heat exchanger 45, and the heat exchanger 45 is disposed in the hot water storage tank 42. The heat exchanger 45 receives and transfers part of the heat absorbed by the cooling plate 224 (surplus heat) to the tap water introduced into the hot water storage tank 42 via the water pipe line 421. By such heat exchange operation, hot water of about 60 ° C. is generated in the hot water tank 42.

  When the temperature of the hot water storage tank 42 is high and the temperature of the battery cooling water CW cannot be sufficiently lowered, the radiator 46 is cooled with air to keep the battery cooling water temperature constant. The valves 48B1 and 48B2 provided in the circulation path 48 and the valve 461B provided in the branch piping 461 branching to the radiator 46 adjust the battery cooling water flow rate so as to control the battery cooling water temperature constant. Is provided.

  By the way, the hydrogen utilization rate in the fuel gas used in the fuel electrode 221 is about 80%, and the remaining 20% hydrogen gas and unreacted gas containing several percent of methane are used as fuel electrode exhaust gas together with carbon dioxide. The fuel electrode 221 is discharged. Moreover, the oxygen utilization rate in the air electrode 222 is about 50 to 60%, and nitrogen gas or the like that does not contribute to the reaction with the remaining oxygen is discharged from the air electrode 222 as air electrode exhaust air. In a general low-temperature fuel cell system, such fuel electrode exhaust gas and air electrode exhaust air are sent to a reformer burner and used as a heat source for reforming. However, in the case of a centralized reforming fuel cell system in which the reformed gas is supplied from the centralized fuel gas supply device 100 as in this embodiment, the reforming device becomes unnecessary in each individual fuel cell unit. It is necessary to effectively utilize the fuel electrode exhaust gas that can be used as

  Therefore, in this individual fuel cell system S1, the exhaust gas pipe line 241 connecting the outlet side of the fuel electrode 221 and the exhaust heat exchanger burner 41a, and the outlet side of the air electrode 222 and the exhaust heat exchanger burner 41a are connected. The exhaust air piping 242 to be connected is provided, and the fuel electrode exhaust gas and the air electrode exhaust air can be introduced into the exhaust heat exchanger burner 41a. Thereby, the fuel electrode exhaust gas discharged from the fuel electrode 221 and the air electrode exhaust air discharged from the air electrode 222 are combusted by the exhaust heat exchanger burner 41a, and the heating section (heat) of the exhaust heat exchanger 41 is heated. By applying heat to the hot water in the temperature raising piping system 44 that passes through the exchange unit 441), the waste energy of the battery stack is utilized.

  That is, when the hot water circulated in the temperature raising piping system 44 is heated by the exhaust heat exchanger burner 41a, only the exhaust heat recovery unit 450 can generate only low temperature water of about 60 ° C., for example, 90 ° C. The hot water can be stored in the hot water storage tank 42. Therefore, the use of hot water supply from the output pipeline 422 is significantly expanded.

  Note that a bypass piping 105 that is directly connected to the main piping 104 is connected to the exhaust gas piping 241 without passing through the PEFC battery stack 210. Similarly, the exhaust air piping 242 is provided with a bypass piping 243 that is directly connected to the air piping 240 without passing through the PEFC battery stack 210. By providing such bypass piping paths 105 and 243, heat can be stably supplied to the exhaust heat exchanger 41 regardless of the operating state of the PEFC unit 200. That is, when the PEFC unit 200 is not operated, the valve 105B and the valve 243B are opened, while the valve 104B is closed, and the fuel gas and air are supplied to the exhaust heat exchanger burner 41a. Thus, the exhaust heat exchanger 41 is configured to operate.

  According to the fuel cell system S1 as described above, a general PEFC unit (low temperature fuel cell unit) can generate only low temperature water of about 60 ° C. using exhaust heat, but is discharged from the cell stack. The fuel electrode exhaust gas and the air electrode exhaust air are combusted by the exhaust heat exchanger burner 41a so that high-temperature water of about 90 ° C. can be generated, and hot water can be supplied to various heat demanding devices. become. Accordingly, the economic efficiency of the fuel cell system S1 can be further improved.

Incidentally, in the case of a household PEFC unit with a power generation capacity of 1 kW, the amount of hydrogen gas used is about 1 Nm ³ / h. When 80% hydrogen gas is used in the battery stack and the remaining 20% hydrogen gas is burned in the exhaust heat exchanger burner 41a,
3050 kcal / h × 0.2 = 610 kcal / h
Energy. When the temperature of about 60 ° C. low temperature water stored in the hot water storage tank 42 is increased to about 90 ° C. high temperature water, the burner combustion efficiency is assumed to be 0.8, and the daily average load factor of the fuel cell is Assuming 0.5, the amount of hot water that can be raised is
610 kcal / h × 24 h × 0.8 × 0.6 / 30 ° C. = 195 liters. The capacity of a hot water storage tank in a general household is normally 200 liters, so that it is possible to cover the amount of heat required to raise the temperature from 60 ° C. to 90 ° C. for the amount of hot water required per day. If the household demands more heat than usual, it is possible to cope with this by burning the reformed gas directly in the exhaust heat exchanger burner 41a using the bypass pipes 105 and 243.

  FIG. 6 is a block diagram illustrating a configuration example of the individual fuel cell system S2 including the SOFC type fuel cell. This fuel cell system S2 has a system configuration in which a solid oxide fuel cell (SOFC) unit 300 as a high-temperature fuel cell unit and an exhaust heat utilization unit 400 including an exhaust heat exchanger 41 are combined. Yes. The fuel cell system S2 uses a battery stack 310 (as a waste energy utilization mechanism for using the waste energy discharged from the battery stack 310 of the SOFC unit 300 as a heating source of the heating unit in the waste heat exchanger 41. A method of directly heating the heating section of the exhaust heat exchanger 41 (the heat exchanging section 441 of the temperature rising piping system 44) by the high-temperature combustion exhaust gas discharged from the combustion chamber 314) is adopted. Hereinafter, the configuration of each part will be described in detail.

  The SOFC unit 300 includes an SOFC battery stack 310, a combustion chamber 314, an air supply device 250 including a blower, an inverter (not shown), and the like. The SOFC battery stack 310 includes a fuel electrode 311, an air electrode 312, and an electrolyte 313. The reformed gas RG serving as the fuel gas is supplied to the fuel electrode 311 through the local piping 103 and the main piping 104, and air A is introduced into the air electrode 312 through the air piping 240 by the air supply device 250. This is the same as the embodiment shown in FIG. 5 in that bypass piping lines 105 and 243 reaching the exhaust heat exchanger burner 41a are provided.

  The configuration of the exhaust heat utilization unit 400 is almost the same as that of the embodiment of FIG. 5, and is composed of an exhaust heat exchanger 41, a hot water storage tank 42, a water recovery tank (water recovery device) 43, a temperature raising piping system 44, and the like. Yes. In addition, in this embodiment, the example which provided the heat exchanger 424 arrange | positioned in the hot water storage tank 42, and the heat exchange part 424 which was arrange | positioned in the hot water storage tank 42 through the hot water storage tank 42 and the heat demand apparatus H was provided. Show. Here, examples of the heat demand device H include an absorption refrigerator (for heating the regenerator) and a 24-hour bath described later.

  In the SOFC unit 300, a combustion chamber 314 is attached to keep the battery stack 310 warm. That is, the fuel electrode exhaust gas and the air electrode exhaust air discharged from the battery stack 310 are combusted in the combustion chamber 314, and the battery stack 310 is kept warm by the heat generated at that time. A combustion exhaust gas pipe 315 for guiding the high-temperature combustion exhaust gas EG combusted in the combustion chamber 314 to the heating unit of the exhaust heat exchanger 41 is attached to the combustion chamber 314. Specifically, the heat exchange unit 441 (heating unit) of the temperature rising piping system 44 is heated by the high temperature combustion exhaust gas EG discharged from the combustion exhaust gas piping 315, and the heat circulated in the temperature rising piping system 44. Heat is given to the medium (low temperature water).

  In the SOFC unit 300 configured as described above, most of the hydrogen component (and carbon monoxide component) in the reformed gas introduced into the fuel electrode 311 is sent from the air electrode 312 in the fuel electrode 311. It reacts with the coming oxygen ions and generates electricity. As described above, air is introduced into the air electrode 312 from the air supply device 250, and oxygen in the air is taken in and ionized. Such oxygen ions move to the fuel electrode 311 through the electrolyte 313 and chemically react with the hydrogen component (and carbon monoxide component) to generate electricity. Since the electric power generated here is direct current, it is supplied as drive power to various electric power devices existing in the consumer after DC-AC conversion by an inverter.

  Generally, the hydrogen utilization rate at the fuel electrode 311 is 70 to 80%, and the remainder is discharged as surplus (fuel electrode exhaust gas). The oxygen utilization rate in the air at the air electrode 312 is 50 to 60%, and the remainder is discharged as surplus (air electrode exhaust air). In order to utilize such surplus energy, the fuel electrode exhaust gas and the air electrode exhaust air are introduced into the combustion chamber 314 disposed on the outlet side of the SOFC battery stack 310 and burned. The heat generated by this combustion is exclusively used to keep the SOFC battery stack 310 warm, but since the exhaust gas EG has high thermal energy, the exhaust heat exchanger in the above-described exhaust gas pipe line 315 is used. It is led to the heating part 41 and is recovered.

  That is, in the exhaust heat exchanger 41, the heat exchanging part 441 of the temperature rising piping system 44 is heated by the combustion exhaust gas EG, and heat is given to the low-temperature water circulated in the temperature rising piping system 44. Thereby, the hot water temperature of the hot water stored in the hot water storage tank 42 can be increased to about 90 ° C. Therefore, according to the fuel cell system S2 as described above, the combustion exhaust gas EG (exhaust energy) discharged from the combustion chamber 314 is effectively utilized, and a fuel cell system excellent in economic efficiency can be provided.

  Next, an embodiment of the centralized fuel gas supply apparatus 100 will be described. FIG. 7 is a block diagram illustrating an example of an internal configuration of the centralized fuel gas supply apparatus 100. The centralized fuel gas supply apparatus 100 includes a centralized fuel gas reformer 10A that generates reformed gas, and a centralized carbon monoxide selective oxidation as a carbon monoxide remover that lowers the carbon monoxide concentration of the reformed gas. And a container 16. The centralized fuel gas reforming apparatus 10A includes a desulfurizer 11 having a sulfur removing function, a steam supply unit 12 that generates steam and adds steam to raw fuel, and a reformer that performs a reforming reaction. (Reformer) 13, a carbon monoxide converter 14 for performing a shift reaction for generating hydrogen and carbon dioxide, and a reformer burner 15 for heating the reformer 13.

The operation of the concentrated fuel gas supply apparatus 100 will be described. A raw fuel such as city gas supplied from the commercial gas supply source 101G (CH ₄ is used in the present embodiment) is first introduced into the desulfurizer 11 and the sulfur component of the odorous material contained in the raw fuel. Is removed. Steam is added from the steam supplier 12 to the desulfurized gas and introduced into the reformer 13. The reformer 13 is heated to an operating temperature of about 750 to 800 ° C. by the reformer burner 15, and the introduced CH ₄ and water are reformed in the reformer 13 using a Ni-based catalyst. , Separated into hydrogen and carbon monoxide. Thereafter, the separation gas is introduced into the carbon monoxide converter 14 maintained at a temperature of 350 to 200 ° C., and the carbon monoxide is converted into hydrogen and carbon dioxide using an Fe-based catalyst or a Cu-based catalyst. . Thereby, the carbon monoxide concentration in the fuel gas (reformed gas) is reduced to about several percent.

  By the way, in the PEFC type fuel cell, it is necessary to supply the reformed gas after the carbon monoxide concentration in the gas is lowered (about 10 to 100 ppm or less). Therefore, in the case where the PEFC units 200 are mixed as in the embodiment shown in FIG. 4, if the reformed gas purified by the centralized fuel gas reforming apparatus 10A is supplied as it is, the PEFC unit 200 is installed. In some customers A, B, E, and G, it is necessary to individually install a carbon monoxide concentration reducing device. Therefore, in the present embodiment, the centralized carbon monoxide selective oxidizer 16 that lowers the carbon monoxide concentration of the reformed gas is provided on the outlet side of the centralized fuel gas reformer 10A. Note that a centralized carbon monoxide adsorber or the like can be used instead of the centralized carbon monoxide selective oxidizer 16, and any device having a function of reducing the carbon monoxide concentration may be used.

  With this configuration, the reformed gas is supplied to the accumulator 120 after the concentration of carbon monoxide contained in the reformed gas purified by the centralized fuel gas reformer 10A is reduced. . In other words, the reformed gas purified in the centralized fuel gas reforming apparatus 10A contains carbon monoxide at a level of several percent. Such a reformed gas is introduced into the centralized carbon monoxide selective oxidizer 16 heated to about 100 ° C., and the carbon monoxide component is converted into carbon dioxide using a Pt-based catalyst. By such a conversion operation, the carbon monoxide concentration of the reformed gas output from the centralized carbon monoxide selective oxidizer 16 is reduced to about 10 to 100 ppm or less.

  Thus, the reformed gas obtained by refining the city gas in the centralized fuel gas supply apparatus 100 is appropriately sent to each of the consumers A to H via the accumulator 120. In the present embodiment, a shunt 141 is provided in the outlet side piping line of the carbon monoxide transformer 14, and a part of the reformed gas purified in the centralized fuel gas reformer 10A is converted into the reformer burner. 15 is provided. This makes it possible to reduce the amount of NOx generated by combustion of the reformer burner 15 to a lower concentration (about 10 ppm) than when using raw fuel such as city gas, LPG, or kerosene. There are advantages that the improvement of the above can be achieved and that the residual gas can be effectively used.

  Furthermore, the PEFC unit 200 is installed by using the centralized carbon monoxide selective oxidizer 16 to reduce the reformed gas to a low carbon monoxide concentration and supplying the reformed gas to each consumer A to H from the centralized fuel gas supply device 100. Also in the consumers A, B, E, and G who are doing, it becomes possible to introduce the said reformed gas into the PEFC unit 200 as it is, and to achieve simplification and size reduction of the PEFC unit 200. Phosphoric acid fuel cells (PAFC) that can tolerate carbon monoxide concentrations up to about 1%, molten carbonate fuel cells (MCFC) that can use carbon monoxide as fuel, and solid electrolyte cells (SOFC) are also available. This is applicable to the present fuel cell system. Note that the general gas appliance 600 is used by modifying the burner structure to be suitable for the reformed gas combustion. Furthermore, if the carbon monoxide concentration is 10 ppm or less, it can be used in conformity with the current Industrial Safety and Health Law, Building Standard Law, Building Management Law, and School Sanitation Law. If a gas leak occurs, there is no possibility of carbon monoxide poisoning, and a gas supply system that is preferable in terms of safety can be obtained.

  Returning to FIG. 4, the operation of the concentrated reforming fuel cell system (wide area fuel cell system) S0 according to the present embodiment described above will be described. In this system S0, fuel gas (reformed gas) is refined from raw fuel (city gas) in a batch by the centralized fuel gas supply device 100 for small consumers A to H existing in a predetermined local area. And distributed to each consumer A to H via the accumulator 120. And in each consumer AH, the fuel cell unit etc. with which each consumer AH receives the supply of the said reformed gas by opening and closing a supply valve (valve 104B shown in FIG. 5, FIG. 6) suitably, etc. Is operated.

  That is, in the consumers A, B, E, and G, when the PEFC unit 200 is operated, the valve 104B is opened, the reformed gas is introduced into the fuel electrode 221 and the operation is executed. In addition, in the customers C and F, when the SOFC unit 300 is operated, the valve 104B is opened, and the reformed gas is introduced into the fuel electrode 311 and the operation is executed. On the other hand, in the consumers D and H in which the fuel cell unit is not introduced, the reformed gas can be supplied to the general gas appliance 600, and the reformed gas is used when the general gas appliance 600 is used. It will be.

  In a consumer in which the PEFC unit 200 or the SOFC unit 300 is arranged, the electric power generated by the operation of each PEFC unit 200 or the SOFC unit 300 is individually utilized as an operation power source of electric equipment in each consumer. The The insufficient power is purchased individually from the commercial power supply source 110G. In addition, the exhaust heat generated by the operation of the PEFC unit 200 or the SOFC unit 300 is used as a heating source of the heating unit in the exhaust heat exchanger 41 combined with each PEFC unit 200 and SOFC unit 300. It is.

  According to the centralized reforming fuel cell system S0 according to the present embodiment described above, (small) fuel cell units (PEFC units 200 or SOFC units 300) or general gas appliances 600 distributed and installed in a plurality of small consumers. Is supplied to the consumer by the centralized fuel gas supply device 100 common to each consumer, while the PEFC unit 200 or SOFC installed in each consumer is used for the power load and heat load of each consumer. This is a configuration corresponding to each unit 300 individually. Therefore, each fuel cell unit does not require a reformer unit, and the device configuration can be simplified and downsized. In addition, since the reformed gas can be constantly supplied, the start-up time is shortened and the fuel cell unit can be operated efficiently. Furthermore, since it respond | corresponds individually using the waste heat of the PEFC unit 200 or SOFC unit 300 with which each consumer is provided with respect to a heat load, the heat loss by heat transport can be suppressed to the minimum.

  Further, since each fuel cell unit does not require a reformer unit, waste energy (exhaust heat) discharged from the PEFC battery stack 210 or SOFC battery stack 310 cannot be utilized in the reformer system. According to the embodiment, the exhaust heat exchanger 41 is combined with each PEFC unit 200 or SOFC unit 300, and the exhaust energy is used as a heating source of the heating unit in the exhaust heat exchanger 41. Therefore, waste energy (waste heat) is also effectively utilized, and a highly economical system can be obtained.

  In the central reforming fuel cell system S0, a shared power system for interconnecting power supply systems to consumers may be provided. In this case, all the power generated by each fuel cell unit is once sent to the shared power system, and each customer purchases the amount of power to be used individually from the shared power system, from the power generated by each fuel cell unit, Surplus power excluding power consumption at each consumer is sent to the shared power grid, and each customer purchases the amount of power used from the shared power grid, or the heat generated from the fuel cell unit of each consumer While the individual power is used by the consumer, the total surplus of the power generated by the fuel cell unit is sold through the shared power system, and the insufficient power is purchased in bulk by the consumer in the local area Etc. can be executed.

  Further, a plurality of the above-described central reforming fuel cell systems S0 may be provided, and the fuel gas may be coordinated between these systems. That is, in the first wide area fuel cell system in which a centralized fuel gas supply apparatus having a fuel gas supply system is installed for each consumer in the first local area, and in the second local area close to the first wide area fuel cell system. Similarly, when there is a second wide area fuel cell system in which a centralized fuel gas supply apparatus having a fuel gas supply system is installed for each consumer, the centralized fuel gas supply apparatus of each fuel cell system It is also possible to provide a connecting pipe line or the like for enabling the fuel gas to be purified to be supplied to other fuel gas supply systems so that the fuel gas can be interchanged.

(Second Embodiment)
Next, a second embodiment of the present invention will be described with reference to FIGS. The second embodiment is an embodiment in which a so-called 24-hour bath is added to a heat demand device in an individual fuel cell system. Since the configuration other than the individual fuel cell system is the same as that of the central reforming fuel cell system S0 described in the first embodiment, the description thereof is omitted.

  FIG. 8 is a block diagram showing a configuration example of an individual fuel cell system S11 having a PEFC type fuel cell. The individual fuel cell system S11 includes a PEFC unit 200, an exhaust heat utilization unit 400 including an exhaust heat exchanger 41, an exhaust heat recovery unit 450 including a battery cooling water heat exchanger 49, and a 24-hour bath unit 500. System configuration. The PEFC unit 200 and the exhaust heat utilization unit 400 are generally the same as those in the embodiment shown in FIG. 5, and different points will be mainly described in order to avoid duplication.

  In this embodiment, two high-temperature and low-temperature heat exchangers are arranged on the heat receiving side, and two hot water storage units that perform high-temperature and low-temperature heat transfer are arranged on the heat radiating side. That is, a waste heat exchanger 41 as a high-temperature heat exchanger, a battery cooling water heat exchanger 49 as a low-temperature heat exchanger, a hot water storage tank 42 as a hot-water storage section for high-temperature heat transfer, and a low-temperature heat transfer And a bathtub 52 of a 24-hour bath unit 500 serving as a hot water storage section.

  And the temperature raising piping system 510 which circulates a heat medium through each of these two heat exchangers and two hot water storage tanks is provided. This temperature raising piping system 510 includes a first heat-feeding pipe line 511 connecting the exhaust heat exchanger 41 and the hot water tank 42, and a second heat return pipe line 512 serving as an output pipe from the hot water tank 42. The fourth piping connecting the third piping 513, the bathtub 52 and the battery cooling water heat exchanger 49, one end of which is connected to the first piping 511 and the second piping 512 and the other end is connected to the bathtub 52. It is comprised from the path 514 and the 5th piping line 515 which connects the battery-cooling-water heat exchanger 49 and the exhaust heat exchanger 41. FIG. The temperature rising piping system 510 in this embodiment is a closed piping path, and the heat medium in the temperature rising piping system 510 is forcibly circulated by a pump 514P provided in the fourth piping path 514.

  As in the embodiment shown in FIG. 5, the exhaust heat exchanger 41 of the exhaust heat utilization unit 400 that functions as a high-temperature heat exchanger is a fuel electrode exhaust gas discharged from the fuel electrode 221 of the PEFC battery stack 210. And the air electrode exhaust air discharged from the air electrode 222 are combusted by the exhaust heat exchanger burner 41a, and the heat exchanging part 441 (exhaust gas) of the temperature rising piping system 510 disposed in the exhaust heat exchanger 41 is burned. The heating unit in the heat heat exchanger 41) is heated, and heat exchange is performed to heat the heating medium (circulated water) in the temperature raising piping system 510 to near 100 ° C.

  The battery cooling water heat exchanger 49 of the exhaust heat recovery unit 450 that functions as a low-temperature heat exchanger has a heat medium in the temperature rising piping system 510 that has been cooled down via the bathtub 52 of the bath unit 500 for 24 hours. Introduced, the heat medium is heated using the exhaust heat of the PEFC battery stack 210. That is, the heat exchange part 451 of the circulation path 48 (similar to the embodiment of FIG. 5) of the cooling water CW passing through the cooling plate 224 attached to the PEFC battery stack 210 is disposed in the battery cooling water heat exchanger 49. Then, the heat absorbed by the cooling water CW in the cooling plate 224 is transferred to the heat medium in the heat exchanging unit 451, whereby the heat medium is heated to about 60 ° C.

  In the hot water storage tank 42 as a hot water storage section for receiving and receiving high-temperature heat, the heat medium in the temperature rising piping system 510 heated to about 100 ° C. in the exhaust heat exchanger 41 is introduced, and heat exchange in the hot water storage tank 42 is performed. Heat is transferred from the portion 44a to the hot water stored in the hot water tank 42. Thereby, the stored hot water in the hot water tank 42 is heated to a high temperature of about 90 ° C.

  A heat medium deprived of a certain amount of heat through the hot water storage tank 42 is introduced into the bathtub 52 of the 24-hour bath unit 500 that functions as a hot water storage part for transferring and receiving low-temperature heat, and a heat exchange part 52a in the bathtub 52 is provided. Therefore, heat is transferred to the hot water stored in the bathtub 52. As a result, the stored hot water in the bathtub 52 is kept at a temperature of about 40 ° C. The 24-hour bath unit 500 includes a bathtub water purification device 53 for removing sterilization and minute hair and dirt components, and a piping system 54 for circulating hot water in the bathtub 52 through the bathtub water purification device 53. Is provided.

  Note that a hot water supply pipe line 503 including a valve 503B is branched to the output pipe line 422 of the hot water storage tank 42, and hot water can be supplied from the hot water supply pipe line 503 to the bathtub 52 of the bath unit 500 for 24 hours. . Further, the third piping path 513 is provided with a valve 513B disposed between a connection portion (branching portion) with the first piping passage 511 and a connection portion (merging portion) with the second piping passage 512. Thus, the opening / closing operation of the valve 513B allows the heat medium to be directly guided from the exhaust heat exchanger 41 to the heat exchange part 52a of the bathtub 52 without passing through the hot water storage tank 42.

  The operation of the individual fuel cell system S11 configured as described above will be described. When the PEFC unit 200 is operated, the heat medium (circulated water) circulating in the temperature rising piping system 510 is heated by the exhaust heat exchanger burner 41a in the heat exchange section 441 of the exhaust heat exchanger 41. Given and heated to near 100 ° C. This heat medium is sent to the hot water storage tank 42 through the first piping 511 of the temperature raising piping system 510 (when the valve 513B is closed). And in the heat exchange part 44a in the hot water storage tank 42, heat exchange with the hot water stored in the hot water storage tank 42 is carried out, and this stored hot water is heated to about 90 degreeC. Accordingly, high temperature water of about 90 ° C. can always be stored in the hot water tank 42.

  The heat medium that has passed through the heat exchanging unit 44a is led out of the hot water storage tank 42 by the second piping 512, and then reaches the third piping 513 to be sent to the bathtub 52 of the bath unit 500 for 24 hours. The heat medium is guided to the heat exchange part 52 a in the bathtub 52 and exchanges heat with the hot water stored in the bathtub 52. Thereby, the hot water temperature of the bathtub 52 is always kept at about 40 degreeC.

  Through such heat exchange, the temperature of the heat medium is reduced to about 40 ° C. or less. Thereafter, the low-temperature heat medium is sent to the battery cooling water heat exchanger 49 through the fourth piping line 514. Then, heat is transferred from the battery cooling water CW that has been heated by passing through the cooling plate 224 of the battery stack in the heat exchanging unit 451, and the temperature is raised to about 60 ° C. Thereafter, the heat medium is returned to the exhaust heat exchanger 41 through the fifth pipe 515 and heated to near 100 ° C. by the exhaust heat exchanger burner 41a. Such a cycle is repeatedly given to the heat medium circulating in the temperature raising piping system 510, so that generation of high-temperature water of about 90 ° C. and warming of hot water in the bathtub 52 are achieved.

  In addition, when the number of bathing people is large or the like, the hot water temperature of the bathtub 52 is always detected in a time zone in which the hot water temperature of the bath is likely to be lowered, and when the temperature is lowered, the valve 513B is opened to open the hot circulating water. May be sent directly to the heat exchanging section 52a of the bath unit 500 for 24 hours to raise the temperature of the hot water. In addition, when the amount of hot water is reduced by using a lot of hot water in a 24-hour bath, open the valve 503B of the hot water supply pipe 503, adjust the hot water temperature, and then supply hot water to the bathtub 52. Also good.

  According to the individual fuel cell system S11 as described above, the hot water storage tank 42 and the 24-hour bath unit 500 are installed in the PEFC unit 200, and the heat medium passed through the hot water storage tank storing hot water is used for 24 hours. Since the bath is kept warm, it is possible to reduce electricity or gas required for keeping warm. Therefore, the heat cost for keeping the 24-hour bath is reduced, and since the hot water is always provided in the 24-hour bath, there is no need for a hot water tank for bath water supply, and the hot water tank can be greatly reduced in size. For example, assuming that a 24-hour bath is installed in a general home, the amount of hot water used for hot water supply in a kitchen or a washroom is about 100 liters, and heat is constantly generated in the fuel cell unit. In consideration of the fact that hot water is stored at a high temperature of about 90 ° C., the size of the hot water storage tank 42 is about 50 to 100 liters, and the hot water storage tank size can be significantly reduced. Further, the heat medium circulating in the temperature raising piping system is first transferred through the hot water storage tank 42 to lower the temperature of the heat medium, and then used for heat insulation through the bath for 24 hours. Since the route is used, the heat medium is used in cascade, and heat exchange can be performed efficiently.

  FIG. 9 is a block diagram illustrating a configuration example of the individual fuel cell system S21 including the SOFC type fuel cell. The individual fuel cell system S21 has a system configuration in which an SOFC unit 300, an exhaust heat utilization unit 400 including an exhaust heat exchanger 41, and a 24-hour bath unit 500 are combined. The SOFC unit 300 and the exhaust heat utilization unit 400 are substantially the same as those in the embodiment shown in FIG. 6, and the configuration of the 24-hour bath unit 500 is the same as that in the embodiment shown in FIG.

  In this embodiment, one high-temperature heat exchanger is disposed on the heat receiving side, and two hot water storage units that perform heat exchange at high and low temperatures are disposed on the heat radiating side. That is, it includes a waste heat exchanger 41 as a high temperature heat exchanger, a hot water storage tank 42 as a hot water storage section for high temperature heat transfer, and a bathtub 52 of a 24-hour bath unit 500 as a low temperature heat transfer hot water storage section. It is a configuration. And the temperature raising piping system 510 which circulates a heat medium through each of these one heat exchanger and two hot water storage tanks is piped. This temperature raising piping system 510A includes a first heat feed piping 511 connecting the exhaust heat exchanger 41 and the hot water storage tank 42, and a second heat return piping 512 serving as an output pipe from the hot water storage tank 42. The third piping 513, one end of which is connected to the first piping 511 and the second piping 512 and the other end of which is connected to the bathtub 52, and the fourth piping connecting the bathtub 52 and the exhaust heat exchanger 41. The path 516 is configured. The temperature rising piping system 510A in this embodiment is also a closed piping path, and the heat medium in the temperature rising piping system 510A is forcibly circulated by a pump 516P provided in the fourth piping path 516.

  This individual fuel cell system S21 is characterized in that the fuel cell unit is the SOFC unit 300, and that the heat exchange part 441 of the temperature raising piping system 510A in the exhaust heat exchanger 41 is exclusively exhausted from the combustion chamber 314. Except for the fact that there is no battery cooling water heat exchanger due to the fact that the battery stack is not equipped with a cooling plate, it has the same configuration as the individual fuel cell system S11 shown in FIG. is there.

  The operation of such an individual fuel cell system S21 will be described. When the SOFC unit 300 is operated, the heat medium (circulated water) circulating in the temperature raising piping system 510A passes through the combustion exhaust gas piping 315 from the combustion chamber 314 in the heat exchange section 441 of the exhaust heat exchanger 41. Heat is given by the supplied flue gas EG and it is heated to near 100 ° C. This heat medium is sent to hot water storage tank 42 through first piping 511 of temperature raising piping system 510A (when valve 513B is closed). And in the heat exchange part 44a in the hot water storage tank 42, heat exchange with the hot water stored in the hot water storage tank 42 is carried out, and this stored hot water is heated to about 90 degreeC. Accordingly, high temperature water of about 90 ° C. can always be stored in the hot water tank 42.

  The heat medium that has passed through the heat exchanging unit 44a is led out of the hot water storage tank 42 by the second piping 512, and then reaches the third piping 513 to be sent to the bathtub 52 of the bath unit 500 for 24 hours. The heat medium is guided to the heat exchange part 52 a in the bathtub 52 and exchanges heat with the hot water stored in the bathtub 52. Thereby, the hot water temperature of the bathtub 52 is always kept at about 40 degreeC. Thereafter, the heat medium is returned to the exhaust heat exchanger 41 through the fourth piping 516, and is heated to near 100 ° C. by the exhaust heat exchanger burner 41a. Such a cycle is repeatedly given to the heat medium circulating in the temperature raising piping system 510A, so that generation of high-temperature water of about 90 ° C. and heat insulation of the hot water in the bathtub 52 are achieved.

  Even with such individual fuel cell system S21, it is possible to similarly reduce the heat insulation cost of hot water stored in the bathtub 52 of the 24-hour bath unit 500 and reduce the size of the hot water tank 42.

  In the second embodiment in which the exhaust heat utilization unit 400 and the 24-hour bath unit 500 described above are combined, various modifications can be made. For example, the temperature rise piping system is provided independently for each of the exhaust heat utilization unit 400 and the 24-hour bath unit 500, and the respective heat exchange units are arranged in the exhaust heat exchanger 41, so that the hot water and the bathtub of the hot water storage tank 42 are provided. It is good also as a structure by which 52 hot water is heated separately.

(Third embodiment)
Next, a third embodiment of the present invention will be described with reference to FIG. In the third embodiment, the hot water storage tank is separated into a high temperature water hot water storage tank and a low temperature water hot water storage tank on the exhaust heat utilization unit side. Since the configuration other than the individual fuel cell system is the same as that of the central reforming fuel cell system S0 described in the first embodiment, the description thereof is omitted.

  FIG. 10 is a block diagram illustrating a configuration example of an individual fuel cell system S12 including a PEFC type fuel cell. The individual fuel cell system S12 has a system configuration in which the PEFC unit 200, the exhaust heat utilization unit 550 including the exhaust heat exchanger 41, and the exhaust heat recovery unit 450 of the battery stack are combined. The PEFC unit 200 and the exhaust heat utilization unit 400 are generally the same as those in the embodiment shown in FIG. 5, and different points will be mainly described in order to avoid duplication.

  The exhaust heat utilization unit 550 in this embodiment includes a high temperature water hot water tank 57 and a low temperature water hot water tank 58. And the temperature rising piping system 560 which circulates a heat medium (circulated water) through these hot water storage tanks 57 and 58 and the exhaust heat exchanger 41 is piping. This temperature raising piping system 560 is a first piping path 561 connecting the exhaust heat exchanger 41 and the high temperature water hot water storage tank 57, and an output pipe from the high temperature hot water storage tank 57, and is a second pipe reaching the low temperature water hot water storage tank 58. It is comprised from the 3rd piping path 563 which connects the piping path 562 and a low-temperature water hot water storage tank, and the waste heat exchanger 41. FIG. This temperature rising piping system 560 is a closed piping path, and the heat medium in the temperature rising piping system 560 is forcibly circulated by a pump (not shown).

  The operation of such an individual fuel cell system S12 will be described. When the PEFC unit 200 is operated, the heat medium (circulated water) circulating in the temperature rising piping system 560 is heated by the exhaust heat exchanger burner 41a in the heat exchange section 441 of the exhaust heat exchanger 41. Given and heated to near 100 ° C. This heat medium is sent to the high-temperature water hot water storage tank 57 through the first piping path 561 of the temperature rising piping system 560. And in the heat exchange part 57a in the high temperature water hot water storage tank 57, it heat-exchanges with the hot water stored in the high temperature water hot water storage tank 57, and heats this stored hot water to about 90 degreeC. Accordingly, high temperature water of about 90 ° C. can be always stored in the high temperature water hot water tank 57. This high-temperature water is supplied with hot water from the output pipe line 571 having the valve 571B to the heat demand equipment in the consumer. In this case, since the hot water supply hot water is high-temperature water of about 90 ° C., it can be used as a heating source for heating the regenerator of the absorption refrigerator.

  The heat medium that has passed through the heat exchanging portion 57 a is sent to the low-temperature water hot water tank 58 through the second piping 562. And in the heat exchange part 58a in the low temperature water hot water tank 58, heat exchange with the hot water stored in the low temperature water hot water tank 58 is carried out. The stored hot water in the low-temperature water hot water tank 58 is also given heat from the heat exchanging unit 452 in the exhaust heat recovery unit 450 that recovers the heat generated by the PEFC battery stack 210. Thereby, this stored hot water comes to be heated to about 60 ° C. This low-temperature water is supplied with hot water from the output piping 581 having the valve 581B to the heat demanding equipment in the consumer. In addition, a connecting pipe line 582 including a check valve 582B is branched from the output pipe line 581, and the low temperature water generated in the low temperature water hot water tank 58 passes through the connecting pipe line 582 to generate hot water. It is configured to be supplied to the hot water tank 57.

  Thereafter, the heat medium is returned to the exhaust heat exchanger 41 through the third piping 563, and is heated to near 100 ° C. by the exhaust heat exchanger burner 41a. By repeatedly applying such a cycle to the heat medium circulating in the temperature rising piping system 560, generation of high temperature water of about 90 ° C. and generation of low temperature water of about 60 ° C. can be achieved. .

  According to the individual fuel cell system S12 described above, after the heat medium in the temperature raising piping system 560 is heated by the exhaust heat exchanger 41, first, it passes through the high temperature water hot water tank 57, and then the low temperature water hot water storage. It is circulated through the tank 58. As a result, the heat obtained by the exhaust heat exchanger 41 is sequentially used in cascade in the high temperature water hot water tank 57 and the low temperature water hot water tank 58, and heat exchange can be performed efficiently. Become.

  In the third embodiment, the case where the fuel cell unit is the PEFC unit 200 has been described. However, when the system is configured using the SOFC unit, the temperature rising piping system 560 in the exhaust heat exchanger 41 is configured. The heat exchanging part 441 is heated exclusively by the combustion exhaust gas EG discharged from the combustion chamber, and the stored hot water in the low temperature water hot water tank 58 is heated only by the heat exchanging part 58a by the temperature raising piping system 560. What is necessary is just to set it as the structure made.

  As mentioned above, although various embodiment was illustrated about the fuel cell system of this invention, this invention is not limited to this. For example, the centralized reforming fuel cell system S0 has been described in the above embodiment, but each of the individual fuel cell systems may be provided with a reforming device individually.

1 is a block diagram schematically showing a configuration of a general fuel cell system. 1 is a block diagram schematically showing the configuration of a intensive reforming fuel cell system according to the present invention. FIG. It is a block diagram which shows the supply form of the electric power and gas with respect to a normal detached house and an apartment house. 1 is a block diagram showing a configuration of a intensive reforming fuel cell system S0 according to a first embodiment of the present invention. FIG. In the said 1st Embodiment, it is a block diagram which shows an example of the individual fuel cell system using the PEFC type fuel cell distributedly arranged by a consumer. It is a block diagram which shows an example of the individual fuel cell system using the SOFC type fuel cell distributedly arranged by a consumer in the said 1st Embodiment. It is a block diagram which shows an example of an internal structure of a concentrated fuel gas supply apparatus. In 2nd Embodiment, it is a block diagram which shows an example of the individual fuel cell system using the PEFC type fuel cell distributedly arranged by a consumer. In 2nd Embodiment, it is a block diagram which shows an example of the individual fuel cell system using the SOFC type fuel cell distributedly arranged by a consumer. In 3rd Embodiment, it is a block diagram which shows an example of the separate fuel cell system using the PEFC type fuel cell distributedly arranged by a consumer. It is a graph which shows the fluctuation state of an electric power load, Comprising: (a) has shown the load fluctuation state of a detached house, (b) has shown the load fluctuation state in an apartment house, respectively. It is a block diagram which shows the structure of the conventional PEFC system. It is a block diagram which shows the structure of the conventional SOFC system.

DESCRIPTION OF SYMBOLS 100 Centralized fuel gas supply apparatus 101 Commercial gas piping system 103 Local piping 104 Main piping (fuel gas piping)
105 Bypass piping (bypass piping system)
120 accumulator 200 PEFC unit (fuel cell unit)
210 PEFC battery stack 300 SOFC unit (fuel cell unit)
310 SOFC battery stack 400, 550 Waste heat utilization unit (waste energy utilization mechanism)
41 Waste heat exchanger 41a Waste heat exchanger burner 42 Hot water storage tank 43 Generated water recovery tank (water recovery device)
44, 510, 510A, 560 Temperature rising piping system 441 Heat exchange section (heating section)
450 Waste heat recovery unit 500 24-hour bath unit 52 Bathtub 57 High-temperature water hot water tank 58 Low-temperature water hot water tank S0 Intensive reforming fuel cell system (wide-area fuel cell system)
S1, S2, S11, S12, S21 Individual fuel cell system A to H Customer EG Combustion exhaust gas

Claims (8)

A fuel cell system that combines a fuel cell unit that generates electricity by introducing fuel gas into a battery stack, and an exhaust heat exchanger having a heating unit,
The exhaust energy discharged from the battery stack of the fuel cell unit, and have a discharge energy utilization mechanism for use as a heating source of the heating unit in the exhaust heat exchanger,
As a heating source of the heating unit in the exhaust heat exchanger, an exhaust heat exchanger burner is provided,
A fuel cell system , wherein a bypass piping system is provided in a piping system for a fuel gas introduced into the battery stack, and the bypass piping system is connected to the exhaust heat exchanger burner . A wide area comprising a fuel gas supply facility that is connected to a commercial gas supply system and purifies a fuel gas that serves as a drive source for the fuel cell, and an individual fuel cell system that is distributed among a plurality of consumers in a predetermined local area Type fuel cell system,
The fuel gas supply facility is a centralized fuel gas supply facility common to each fuel cell unit capable of supplying fuel gas to each consumer,
The individual fuel cell system is a combination of a fuel cell unit that generates electricity by introducing the fuel gas into a battery stack, and an exhaust heat exchanger that includes a heating unit,
The exhaust energy discharged from the battery stack of the fuel cell unit, and have a discharge energy utilization mechanism for use as a heating source of the heating unit in the exhaust heat exchanger,
As a heating source of the heating unit in the exhaust heat exchanger, an exhaust heat exchanger burner is provided,
A wide-area fuel cell system , wherein a bypass piping system is provided in a piping system for fuel gas introduced into the battery stack, and the bypass piping system is connected to the exhaust heat exchanger burner. . The fuel cell unit comprises a high-temperature fuel cell unit;
2. The exhaust energy utilization mechanism further includes a mechanism for directly heating a heating unit in the exhaust heat exchanger by high-temperature combustion exhaust gas discharged from a battery stack of the high-temperature fuel cell unit. Or the fuel cell system of 2. The fuel cell unit comprises a low-temperature fuel cell unit ;
The exhaust energy utilization mechanism is configured to send the fuel electrode exhaust gas and the air electrode exhaust air discharged from the battery stack of the low-temperature fuel cell unit to the exhaust heat exchanger burner for combustion. The fuel cell system according to claim 1 or 2. The fuel cell unit has a hot water storage tank for storing hot water.
5. A temperature rising piping system in which a heat medium is circulated for transferring heat given by the exhaust heat exchanger to hot water in the hot water storage tank is provided. Fuel cell system. The fuel cell unit is equipped with a hot water storage tank for storing hot water and a bathtub equipped with a bathtub water purification device,
5. A temperature rising piping system for transferring heat given by the exhaust heat exchanger to hot water in the hot water tank and / or hot water in the bathtub is provided. A fuel cell system according to claim 1. The hot water tank is separated into a hot water hot water tank and a low temperature water hot water tank,
The temperature raising piping system is piped through the high temperature water hot water tank and the low temperature water hot water tank,
The heating medium in the temperature rising piping system is configured to be circulated through the high-temperature water hot water tank first after passing through the exhaust heat exchanger, and then through the low-temperature water hot water tank. The fuel cell system according to claim 5. The exhaust heat exchanger is provided with a water recovery device that recovers water contained in the high-temperature combustion exhaust gas discharged from the battery stack or the combustion exhaust gas of the exhaust heat exchanger burner as drain water. The fuel cell system according to any one of claims 1 to 7 .

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