JP2006073264A - Fuel cell power generation system and warm water producing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generation system achieved in small size and light weight as a whole, when packaged units are integrated. <P>SOLUTION: The fuel cell power generation system integrates a packaged unit for housing a power generation system including a fuel cell body 1 and a packaged unit for housing a hot water tank 2. Hot water stored in the hot water tank 2 is heated by warmers 10, 11, thereby the hot water tank 2 is made relatively small in size and light in weight. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention generally relates to a fuel cell power generation system that generates power using a fuel containing hydrogen, and in particular, a fuel cell power generation system including a hot water storage tank that stores hot water obtained by using heat generated by power generation. About.

  In recent years, development of fuel cell power generation systems that generate power using, for example, city gas or the like as raw fuel and using hydrogen contained in the raw fuel (in practice, hydrogen-rich gas) has been promoted.

  In addition, a system that uses hydrogen gas or reformed gas (hydrogen-rich gas produced from city gas) as raw fuel is being developed in parallel with the prospect of promoting the development of hydrogen infrastructure.

  In such a fuel cell power generation system, in addition to the fuel cell main body, a hot water storage tank that stores hot water obtained by using heat generated by power generation, an inverter that converts direct current output from the fuel cell main body into alternating current, and a control device Practical use of integrated systems including the above has been attempted. Such an integrated configuration is useful not only for electric power but also for hot water, and is particularly useful for small fuel cell power generation systems that are being developed for general household use.

  By the way, the specific structure of the integrated system is mainly divided into two units: a package unit (housing) for storing a hot water storage tank and a package unit for storing a power generation system including other fuel cell bodies. The structure is general (see, for example, Patent Documents 1 and 2).

  These two package units are individually installed and connected by piping and electric wires to exchange heat energy between them (specifically, generation of hot water) and exchange various signals.

In particular, in a fuel cell power generation system that uses hydrogen gas or reformed gas as a raw fuel, the package unit that houses the power generation system is not consumed for power generation at the anode (fuel electrode) included in the fuel cell body. A facility is provided to dissipate hydrogen into the atmosphere after being diluted to a sufficiently safe concentration.
JP 2004-111208 A JP 2004-111209 A

  Since the conventional integrated fuel cell power generation system is divided into two package units, when these units are installed in, for example, a garden of a general household or a veranda of a condominium, securing an installation space becomes an issue. ing.

  Also, when performing installation work, the foundation work of both package units, the piping work between both package units, and electrical instrumentation work are required, and the cost and time required for that work are not small, so there is a problem of reducing them. There is.

  Here, if the reason why the integrated fuel cell power generation system is divided into two package units is given, the following two reasons can be considered. That is, the first reason is the problem of size and weight constraints. The second reason is a technical problem for storing all system elements in one package unit.

  For example, taking a fuel cell power generation system for general households as an example, the dimensions of the package unit that houses the power generation system including the fuel cell main body are, for example, a width of 80 cm, a depth of 30 cm, a height of 85 cm, and a weight of about 140 kg. It is expected that. The dimensions of the package unit for storing the hot water storage tank are expected to be, for example, about 75 kg in width, 45 cm in depth, 190 cm in height, and about 300 kg in weight when full. When these two package units are integrated, it is expected that the size and weight will be excessive when they are installed in a general household garden or a condominium veranda.

  Conventionally, in a small fuel cell power generation system having a power generation capacity of 10 kW or less, equipment and piping that handle flammable gas, air-related equipment and piping that does not handle flammable gas, electrical equipment and wiring, and hot water storage tanks In addition, there is no actual example in which equipment and piping that handle battery cooling water and hot water (hot water) are housed in the same package unit. In addition, the technical problems and safety considerations in that case, and the design based on them are not made practically.

  Accordingly, an object of the present invention is to realize a reduction in size and weight as a whole when integrating package units, resulting in space saving during installation, cost reduction of installation work, and a reduction in time. The object is to provide a fuel cell power generation system that can be shortened.

  An aspect of the present invention relates to a fuel cell power generation system that integrates a package unit that stores a power generation system including a fuel cell body and a package unit that stores a hot water storage tank. This is a fuel cell power generation system that has been realized and as a result has achieved overall reduction in size and weight.

  A fuel cell power generation system according to an aspect of the present invention includes a fuel cell main body that generates power using a fuel containing hydrogen, a hot water storage tank that stores hot water heated by heat generated by power generation of the fuel cell main body, And a heating means for generating heat using a part of the fuel to heat the warm water.

  With such a configuration, the temperature of the hot water stored in the hot water storage tank can be made relatively high. Therefore, it becomes possible to store more heat with the same amount of hot water storage. Therefore, as a result, it is possible to reduce the size and weight of the hot water storage tank that stores hot water used for supplying hot water of the required temperature and amount.

  According to the present invention, since the hot water storage tank for storing hot water can be reduced in size and weight, the package unit for storing the hot water storage tank can be reduced in size and weight. Therefore, when a fuel cell power generation system is constructed by integrating the package unit and a package unit containing a power generation system including a fuel cell main body, a small and light fuel cell power generation system can be provided as a result. . As a result, it is possible to save space when installing the system and to reduce the cost and period of installation work.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a main part of the fuel cell power generation system according to the first embodiment.

  As shown in FIG. 1, this system is roughly divided into a fuel cell body 1, a hot water storage tank 2, a battery cooling water system 6, and a heat utilization system 9, and is configured as one package unit.

  The fuel cell body 1 has an anode part (fuel electrode) 3, a cathode part (air electrode) 4, and an electrolyte part 5. Hydrogen (hydrogen rich gas) 100 necessary for power generation is supplied to the anode unit 3. In addition, air 200 is supplied to the cathode portion 4. The air 200 is supplied by an air blower (not shown).

  The hot water storage tank 2 is a tank for storing hot water, which will be described later, to which a water supply pipe 13 and a hot water supply pipe 14 are connected. The hot water storage tank 2 is supplied with water 400 through the water supply pipe 13. The water 400 is also supplied to the hot water supply pipe 14 through the hot water supply temperature adjustment valve 16 by the water supply bypass pipe 15.

  Hot water stored in the hot water storage tank 2 is sent to the outside as hot water supply 500 through the hot water supply temperature control valve 16 and the hot water supply pipe 14. In order to supply hot water at a required temperature, a temperature detector 17 is installed together with the hot water supply temperature adjustment valve 16.

  The battery cooling water system 6 is a system for removing and recovering heat generated when the fuel cell main body 1 generates power, and includes a battery cooling water pump 7 and a battery exhaust heat recovery heat exchanger 8. The heat utilization system 9 is a system for generating hot water from the water 400 supplied to the hot water storage tank 2 using heat generated by the power generation of the fuel cell main body 1 and heat generated by a heater described later.

  Specifically, the heat utilization system 9 includes a heat utilization pump 12 that extracts water from the hot water storage tank 2, a battery exhaust heat recovery heat exchanger 8, and a heater (10, 11). The battery exhaust heat recovery heat exchanger 8 recovers heat generated when the fuel cell main body 1 generates power, and warms the water taken out by the heat utilization pump 12.

  The warmer includes a hydrogen oxidation reactor 10 and a hydrogen reaction heat recovery heat exchanger 11, and is an element that further warms the hot water from the battery exhaust heat recovery heat exchanger 8. The hydrogen oxidation reactor 10 is a device that introduces hydrogen (hydrogen-rich gas) that is discharged without being consumed by the anode unit 3 and causes an oxidation reaction between the hydrogen and oxygen in the air 200, and the reaction heat is converted into hydrogen reaction heat. The recovered heat exchanger 11 is supplied. The hydrogen reaction heat recovery heat exchanger 11 warms the hot water from the battery exhaust heat recovery heat exchanger 8 with the reaction heat and sends it to the system for returning to the hot water storage tank 2.

(Operational effects of the first embodiment)
First, the fuel cell main body 1 generates power by supplying hydrogen (hydrogen-rich gas) 100 to the anode portion 3 and supplying air 200 to the cathode portion 4. The battery exhaust heat recovery heat exchanger 8 recovers heat (for example, about 70 ° C.) generated by this power generation.

  On the other hand, the hot water storage tank 2 is supplied with water 400 through the water supply pipe 13. The water accumulated in the hot water storage tank 2 is taken out by the heat utilization pump 12 and sent to the battery exhaust heat recovery heat exchanger 8. By this battery exhaust heat recovery heat exchanger 8, the water accumulated in the hot water storage tank 2 becomes warm water of about 60 ° C., for example.

  Here, in the anode unit 3, all of the supplied hydrogen (hydrogen-rich gas) 100 is not consumed for power generation, but a part 110 thereof is discharged. This is due to the restrictions on the characteristics of the fuel cell. If the hydrogen consumption rate (hydrogen utilization rate) at the anode part 3 is too high, the hydrogen deficiency partially occurs and the battery is damaged. This is because there is a possibility.

  The hydrogen oxidation reactor 10 introduces hydrogen (hydrogen rich gas) 110 discharged from the anode unit 3 and reacts with oxygen in the air 200 to generate reaction heat. The hydrogen oxidation reactor 10 includes a hydrogen burner that burns hydrogen, or a catalyst burner that reacts hydrogen with oxygen in the air by the action of a catalyst.

  The hydrogen reaction heat recovery heat exchanger 11 recovers the reaction heat (for example, about 200 to 300 ° C.) generated from the hydrogen oxidation reactor 10 and warms hot water sent from the battery exhaust heat recovery heat exchanger 8, The temperature of hot water of about 60 ° C. is raised to, for example, about 90 ° C.

  With such an action, along with the power generation of the fuel cell main body 1, the hot water storage tank 2 accumulates hot water heated to, for example, about 90 ° C. from the supplied water 400. Therefore, hot water of, for example, 90 ° C. or less can be supplied from the hot water storage tank 2 through the hot water supply temperature adjustment valve 16 and the hot water supply pipe 14.

As described above, according to the present embodiment, when the reaction temperature of the fuel cell body 1 is about 70 ° C.,
After warm water of about 60 ° C., for example, is generated by the battery exhaust heat recovery heat exchanger 8 of the heat utilization system 9, the warm water is further raised to a high temperature of about 90 ° C. by the heater (10, 11).

  Accordingly, the hot water tank 2 can store hot water heated to a high temperature of about 90 ° C. In other words, by increasing the temperature of the hot water stored in the hot water storage tank 2 from about 60 ° C. to about 90 ° C., more heat can be stored with the same amount of hot water storage. For this reason, as a result, the hot water storage tank 2 for supplying hot water at a required temperature and amount of hot water can be relatively reduced in size and weight.

  More specific examples are shown below. For example, in a general household, about 300 liters of warm water per day is used on average in a bath or kitchen. Here, when the hot water supply temperature is about 45 ° C. and the hot water is supplied from a hot water storage tank having a hot water storage temperature of about 60 ° C., the water temperature of tap water needs to be 20 ° C. and it is necessary to store about 190 liters of hot water.

  On the other hand, in this embodiment, hot water having a high temperature of about 90 ° C. can be stored. Therefore, when the above condition is satisfied, about 110 liters of hot water may be stored in the hot water storage tank 2. Therefore, the hot water storage tank 2 in this embodiment can be relatively reduced in size and weight. As a result, when the package unit that stores the power generation system including the fuel cell main body 1 and the package unit that stores the hot water storage tank 2 are integrated to form a fuel cell power generation system as one package unit, it is small and lightweight. The fuel cell power generation system can be realized.

  In particular, when applied to a general household fuel cell power generation system, the entire system can be reduced in size and weight, so that the system can be easily installed in a limited installation space such as a general household garden or condominium veranda. It becomes possible to install in. In addition, the cost of installation work can be reduced and the period can be shortened.

(Another effect of this embodiment)
Furthermore, the fuel cell power generation system of the present embodiment can obtain the following effects.

  That is, the energy of the hydrogen 110 discharged from the fuel cell system can be recovered and used in the form of hot water, and as a result, the heat recovery efficiency of the fuel cell system can be increased.

  To explain with a specific example, when the hydrogen utilization rate in the anode part 3 of the fuel cell main body 1 is 90%, 10% of the supplied hydrogen is discharged from the anode part 3 without being used for power generation. By recovering this 10% hydrogen energy in the form of hot water, the heat recovery efficiency can be increased by 10 points.

  Further, an ordinary system requires an air blower for diluting hydrogen discharged from the anode portion 3 of the fuel cell main body 1 to a sufficiently safe concentration to dissipate into the atmosphere. On the other hand, if it is the structure of this embodiment, since the motive power of the said air blower can be made unnecessary, as a result, the power generation efficiency of a system can be improved. In other words, it is possible to realize a system excellent in energy saving with little energy loss.

  As a specific example, a trial calculation with a 700 W rated fuel cell system results in approximately 60 liters of hydrogen being discharged per hour when the hydrogen utilization rate at the anode 3 is 90%. Since the combustion range of hydrogen is very wide and burns at a concentration of about 4% or more, it is necessary to dilute to a concentration sufficiently lower than this in order to dissipate into the atmosphere. Normally, it is diluted to about 1/10 of the lower combustion limit concentration, and about 7 W is required as blower power for sending air necessary for this purpose. By eliminating this power, the power generation efficiency (power transmission end efficiency) of the system is improved by about 0.3 points.

  Furthermore, since no hydrogen is contained in the plant exhaust, management items for system operation can be reduced. In addition, it is effective in reducing psychological anxiety of users of the installed system.

  In the present embodiment, the hydrogen oxidation reactor 10 has been described as a configuration that generates a heat of reaction by introducing a part 110 of the hydrogen (hydrogen-rich gas) 100 discharged from the anode unit 3. However, the present invention is not limited to this, and as shown in FIG. 1, the hydrogen oxidation reactor 10 generates reaction heat by introducing, for example, part of hydrogen gas or hydrogen rich gas 300 obtained by bypassing the anode unit 3. It may be configured.

(Second Embodiment)
FIG. 2 is a block diagram showing a main part of the fuel cell power generation system according to the second embodiment. In addition, about the same element shown in above-mentioned FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 2, the system according to the present embodiment is configured as one package unit having a first room 20, a second room 21, and a third room 22 that are partitioned by a partition wall.

  The first room 20 is a room in which a fuel cell main body 1 that handles combustible gas, and hydrogen system equipment and piping including a hydrogen oxidation reactor 10 and a hydrogen reaction heat recovery heat exchanger 11 are housed. The second room 21 is a room that houses an air system that does not handle flammable gas, a battery cooling water system 6, a heat utilization system 9, and electrical equipment including an inverter 18 and a control device 19, piping, and wiring. The third room 22 is a room in which peripheral equipment and piping of the hot water supply system including the hot water storage tank 2 are stored.

  The first room 20 is provided with an exhaust ventilation fan 23 and an intake port 24. The second room 21 is provided with an intake ventilation fan 25 and an exhaust port 26. The third room 22 is a closed type or has a structure in which openings are provided in the upper and lower parts of the room and forced ventilation is not performed although not shown.

(Operational effects of the second embodiment)
In addition, about the effect of the fuel cell power generation system containing a hot water supply system, since it is the same as that of above-mentioned 1st Embodiment, description is abbreviate | omitted.

  In the first room 20, the ventilation air flows from the intake port 24 and is forcibly exhausted by the ventilation fan 23 provided at the most downstream side of the flow of the ventilation air, that is, the exhaust port part of the room. Since the downstream of the ventilation fan 23 is atmospheric pressure, the inside of the first chamber 20 is maintained at a negative pressure. Therefore, even if a flammable gas leaks inside the first chamber 20, the risk of the flammable gas flowing out from a portion other than the exhaust port (23) can be eliminated.

  In the second room 21, the ventilation air is pushed into the room by the ventilation fan 25 provided in the uppermost stream, that is, the air inlet of the room, and is discharged from the exhaust 26. Therefore, even if the outside of the second chamber 21 becomes a flammable gas atmosphere, there is a possibility that the flammable gas may flow into the second chamber 21 from a portion other than the intake port (25). Can be eliminated. Thereby, the risk of ignition caused by electrical equipment such as the inverter 18 installed in the second room 21 can be avoided.

  Moreover, if the 3rd chamber 22 is made into a sealing type, the heat loss from the hot water storage tank 2 and attached piping can be suppressed to the minimum. In order to eliminate risks such as deterioration and failure of equipment due to leakage of hot water, performance degradation, etc., it is effective to provide a small diameter opening (hole) in the lower part of the third room 22. In this case, in order to avoid the risk that hydrogen flows from the lower opening and stays in the third room 22, a small-diameter opening (hole) is also provided in the upper part of the room. is required.

  According to this embodiment having the above configuration and operation, the entire fuel cell power generation system can be compactly accommodated as one package unit without impairing the function and safety of each system. Accordingly, the system can be easily installed even in places where the installation space is limited, such as a garden of a general household or a veranda of a condominium. In addition, the piping work between the package units and the electrical / instrumentation work during the installation work are not required, and the cost and time for the work can be shortened.

(Third embodiment)
FIG. 3 is a block diagram showing a main part of the fuel cell power generation system according to the third embodiment. In addition, about the same element shown in above-mentioned FIG.1 and FIG.2, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 3, the system of this embodiment is configured such that the intake port 24 of the first room 20, the exhaust port 26 of the second room 21, and the ventilation fan 25 of the second room 21 are deleted. The ventilation passage 27 is provided between the room 20 and the second room 21. The other structures are the same as those in FIG.

(Operational effect of this embodiment)
In the system of the present embodiment, the ventilation air flows from the air inlet 28 of the second room 21, ventilates the second room 21, and then flows into the first room 20 via the ventilation passage 27. . The ventilation air that has flowed into the first room 20 flows through the room and is then exhausted to the atmosphere by the ventilation fan 23.

  Even in a system having such a structure, the same effects as those of the second embodiment described above can be obtained.

  As described above, according to the embodiments, in the fuel cell power generation system including the integrated package unit, the entire system can be reduced in size and weight. Therefore, it is possible to save the installation space when installing the system, reduce the cost of installation work, and shorten the period. Furthermore, it is possible to provide a fuel cell power generation system with high power generation efficiency and heat recovery efficiency and excellent safety.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The block diagram which shows the principal part of the fuel cell power generation system regarding the 1st Embodiment of this invention. The block diagram which shows the principal part of the fuel cell power generation system regarding 2nd Embodiment. The block diagram which shows the principal part of the fuel cell power generation system regarding 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell main body, 2 ... Hot water storage tank, 3 ... Anode part, 4 ... Cathode part, 5 ... Electrolyte part,
6 ... battery cooling water system, 7 ... battery cooling water pump, 8 ... battery exhaust heat recovery heat exchanger,
9 ... Heat utilization system, 10 ... Hydrogen oxidation reactor, 11 ... Hydrogen reaction heat recovery heat exchanger,
12 ... Heat utilization pump, 13 ... Water supply pipe, 14 ... Hot water supply pipe, 15 ... Water supply bypass pipe,
16 ... Hot water temperature control valve, 17 ... Hot water temperature detector, 18 ... Inverter, 19 ... Control device,
20 ... 1st room, 21 ... 2nd room, 22 ... 3rd room, 23 ... Ventilation fan,
24 ... Inlet, 25 ... Ventilation fan, 26 ... Exhaust, 27 ... Ventilation passage,
28 ... Inlet.

Claims (12)

A fuel cell body that generates power using fuel containing hydrogen;
A hot water storage tank for storing hot water heated by heat generated by power generation of the fuel cell body;
A fuel cell power generation system comprising heating means for generating heat using a part of the fuel and heating the hot water.   2. The fuel cell power generation system according to claim 1, wherein the heating unit generates heat of oxidation reaction of hydrogen that is a part of the fuel to heat the hot water. 3.   The heating means is configured to introduce hydrogen discharged in addition to hydrogen consumed from the anode part included in the fuel cell main body, generate oxidation reaction heat of the hydrogen, and warm the warm water. The fuel cell power generation system according to claim 1.   The heating means includes a catalytic combustor, wherein the hydrogen is introduced into the catalytic combustor and oxidized to generate heat of oxidation reaction of the hydrogen to warm the hot water. The fuel cell power generation system according to any one of claims 1 to 3. Means for taking out water supplied to the hot water storage tank and returning warm water heated by heat generated by power generation of the fuel cell body to the hot water storage tank;
The fuel cell power generation system according to any one of claims 1 to 4, wherein the heating means is configured to heat the hot water before returning it to the hot water storage tank. Including an inverter that converts direct current generated by power generation of the fuel cell body into alternating current;
6. The fuel cell power generation according to claim 1, wherein the fuel cell power generation unit is configured as one package unit that accommodates each of the fuel cell main body, the hot water storage tank, and the heating unit. system. Dividing the package unit into first to third rooms which are independent from each other;
In the first room, the fuel cell main body for handling the combustible gas and the hydrogen system piping and equipment including the heating means are stored,
The second room contains an air system that does not handle flammable gas, a battery cooling water system, and electrical equipment including the inverter, wiring, and piping.
The fuel cell power generation system according to claim 6, wherein the hot water storage tank is stored in the second room.   8. The fuel cell power generation system according to claim 7, wherein the first room has a structure in which a ventilation fan is provided at the most downstream side of the flow of ventilation air, that is, on the exhaust port side of the room for forced ventilation. .   9. The second room according to claim 7, wherein the second room has a structure in which a ventilation fan is provided on the most upstream side of the flow of the ventilation air, that is, on the intake port side of the room for forced ventilation. 2. A fuel cell power generation system according to item 1.   The third room according to any one of claims 7 to 9, wherein the third room is a closed type or has a structure in which openings are provided at the top and bottom of the room and forced ventilation is not performed. Fuel cell power generation system.   The fuel cell power generation system according to any one of claims 7 to 10, wherein the fuel cell power generation system has a structure in which an intake port of the first room and an exhaust port of the second room are connected. A hot water generation method applied to a fuel cell power generation system having a fuel cell main body that generates power using a fuel containing hydrogen and a hot water storage tank for storing hot water,
A process of generating hot water having a first temperature by heating water supplied to the hot water storage tank by heat generated by power generation of the fuel cell main body;
A process of generating warm water having a second temperature that is higher than the first temperature by heating the warm water by a heating means using a part of the fuel;
And a process of supplying hot water having the second temperature to the hot water storage tank.

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