JP2003217623A - Solid polymer electrolyte fuel cell generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a solid polymer electrolyte fuel cell generator capable of preventing water from being condensed in a pipe for feeding reformed gas (hydrogen) humidified during the starting of the generator or the like to a fuel cell without degrading the efficiency of the entire generator, shortening the starting time, and consistently demonstrating the high performance of the fuel cell. <P>SOLUTION: At least a part of a pipe to feed the humidified hydrogen to the fuel cell 1 forms a double pipe heat exchanger 24, the humidified hydrogen is passed through an inner pipe of the double pipe heat exchanger 24, and cooling water discharged from the fuel cell 1 is passed through an outer pipe of the double pipe heat exchanger 24 to prevent the pipe from being heated and prevent the water from being condensed inside the pipe. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer electrolyte fuel cell power generator suitable as a small-sized power source for home use, for example.

[0002]

2. Description of the Related Art Recently, a reformer for reforming hydrocarbon fuel gas such as natural gas, city gas, methanol, LPG, butane to hydrogen, a CO shifter for transforming carbon monoxide, and a carbon monoxide. For removing CO, a fuel cell for generating electric power by chemically reacting the hydrogen (reformed gas) thus obtained with an oxidizing agent such as oxygen in the air, and cooling the electrode section of the fuel cell A polymer electrolyte fuel cell power generator as a small power source including a cooling device, a heat exchanger that recovers the heat of exhaust gas from the reformer, the fuel cell, and the like into hot water, and a hot water storage tank that stores the hot water Is proposed.

A solid polymer electrolyte membrane used in a solid polymer fuel cell power generator functions as a proton conductive electrolyte by containing water. In the solid polymer fuel cell, reaction air, fuel gas, etc. A method is employed in which the reaction gas is saturated with water vapor and supplied to the electrode portion to operate.

When a fuel gas containing hydrogen is supplied to the fuel electrode and air is supplied to the air electrode, a fuel electrode reaction is carried out to decompose hydrogen molecules into hydrogen ions and electrons in the fuel electrode, and water is generated from oxygen, hydrogen ions and electrons in the air electrode. Each of the electrochemical reactions to generate the electric current is performed, and the electric power is supplied to the load by the electrons moving in the external circuit from the fuel electrode toward the air electrode, and the water is generated on the air electrode side.

FIG. 3 is an explanatory view of a conventional polymer electrolyte fuel cell power generator (PEFC device GS). Fuel cell 1
The PEFC apparatus GS that uses is including, for example, the heat recovery apparatus RD in addition to the fuel cell 1. This heat recovery device RD
Is provided with a hot water storage tank (not shown), heat exchangers 2 and 10, a hot water circulation path including a pump 5, and the like.

The fuel cell 1 comprises a reformed gas supply device including a desulfurizer, a reformer, a CO shifter, a CO remover, a fuel gas humidification tank 6 and the like, a pump 15 and an oxidizer humidification tank 7 which are not shown. Reaction air supply device and electrodes such as the fuel electrode 1a and the air electrode 1k and the conduits 20, 2
1, a cooling device CD for the fuel cell 1 including a pump 18, a solenoid valve 14, a cooling unit 1c, and the like.

The electric power generated by the fuel cell 1 is boosted by a DC / DC converter (not shown) and connected to a commercial power source through an inverter (not shown) connected to a distribution system.
From here, it is supplied as electric power for other electric devices such as lighting and air conditioners in homes and offices.

In the PEFC device GS using such a fuel cell 1, hot water is generated from city water by utilizing heat generated at the time of power generation by the fuel cell 1, and the hot water is stored in a hot water storage tank (not shown). In order to effectively use the energy of the fuel used in the fuel cell 1, such as storing it in a bath or supplying it to a kitchen.

In the fuel gas supply device of the PEFC device GS described above, a hydrocarbon-based raw fuel such as natural gas, city gas, methanol, LPG, butane is supplied to a desulfurizer, where a sulfur component is removed from the raw fuel. To be done. When the raw fuel that has passed through the desulfurizer is boosted by a booster pump and supplied to the reformer, it joins steam and is supplied. In the reformer, reformed gas containing hydrogen, carbon dioxide, and carbon monoxide is generated. The gas that has passed through this reformer is supplied to a CO shift converter, where carbon monoxide contained in the reformed gas is transformed into carbon dioxide. The gas that has passed through this CO transformer is CO
The unconverted carbon monoxide in the gas passed through the CO shift converter is reduced to, for example, 10 ppm or less, and the water gas (reformed gas) having a high hydrogen concentration is supplied to the fuel gas humidification tank 6. Humidification is performed by bubbling the fuel gas into the hot water (for example, 75 to 78 ° C.) in the fuel gas humidifying tank 6 and sending it to the gas phase portion. In this way, the reformed gas that has been moistened so that the reaction in the fuel cell 1 is appropriately maintained is supplied to the fuel electrode 1a of the fuel cell 1 through the conduit 22. 11 is a perforated plate for bubbling.

In the reaction air supply device, an oxidizing agent such as air is supplied to the oxidizing agent humidifying tank 7 by a pump 15 and is bubbled into hot water (for example, 60 to 65 ° C.) in the oxidizing agent humidifying tank 7 and sent to the gas phase portion. Humidification is performed by doing. In this way, the reaction air that has been moistened so that the reaction in the fuel cell 1 is appropriately maintained is supplied to the air electrode 1k of the fuel cell 1 through the conduit 23. 1
2 is a perforated plate for bubbling.

In the fuel cell 1, electricity is generated by an electrochemical reaction between hydrogen in the reformed gas supplied to the fuel electrode 1a and oxygen in the air supplied to the air electrode 1k. The cooling device CD of the fuel cell 1 is designed to prevent the fuel cell 1 from overheating due to the reaction heat of this electrochemical reaction.
Is a cooling device juxtaposed with the electrodes 1a, 1k of the fuel gas humidifying tank 6 in the cooling unit 1c is circulated through the pipe 20 as cooling water by the pump 18, and the temperature in the fuel cell 1 is increased by this cooling water. Suitable temperature for power generation (eg 78-80)
The temperature is controlled so that it is maintained at about (° C). In this way, in the fuel cell 1, a predetermined chemical reaction and power generation are continued.

Reference numeral 13 is a temperature sensor (set value: for example, 78 to 80 ° C.) installed at the outlet of the cooling section 1c of the cooling water circulation path.
When the temperature detected by the temperature sensor 13 exceeds the set value, a signal is sent from the control device (not shown) to the solenoid valve 14, the solenoid valve 14 is opened, and the hot water in the fuel gas humidification tank 6 is passed through the pipe 21 to an appropriate amount. The hot water that has been sent to the oxidant humidifying tank 7 and that has exchanged heat with the hot water in the oxidant humidifying tank 7 is added to the hot water in the pipeline 20 and circulated as cooling water to the fuel cell 1 to be sent, and the temperature in the fuel cell 1 is used for power generation. It is designed to control to a suitable temperature. Reference numeral 16 is a perforated plate for a shower installed in the upper gas phase portion in the fuel gas humidification tank 6 of the cooling water circulation path, and assists humidification of the fuel gas.

On the other hand, the hot water in the oxidant humidifying tank 7 is introduced into the heat exchanger 10 by the pump 5 and exchanges heat with the exhaust gas from the air electrode 1k to circulate the hot water in the oxidant humidifying tank 7 to maintain a predetermined temperature. It has become. Reference numeral 19 denotes a temperature control device which sends a signal to the pump 5 to operate the pump 5 so as to maintain the temperature of the hot water in the oxidizer humidification tank 7 at a predetermined temperature. In addition, the city water is sent to the heat exchanger 10 and the air electrode is 1k.
After heating by exchanging heat with the exhaust gas of the above, it is guided to the heat exchanger 2 and exchanges heat with the exhaust gas of the fuel electrode 1a to be further heated, and then sent to a hot water storage tank (not shown) to store hot water and, if necessary, supply hot water to the outside. .

The PEFC device GS having the above structure is
Since it takes the form of a cogeneration system of power generation and heat utilization, not only is the power generation efficiency of the fuel cell improved,
This has the effect of effectively reusing the water used in this system.

[0015]

However, when the humidified reformed gas is supplied to the fuel electrode 1a of the fuel cell 1 through the conduit 22, especially when the temperature of the conduit 22 is low at the time of starting. Means that water condenses in the pipe to block the conduit 22, or the condensed water is supplied to the fuel electrode 1a, and the supply of the reformed gas to the fuel electrode 1a becomes unstable, or the supply is stopped. However, there is a problem that stable and high fuel cell performance cannot be exhibited. Therefore, conventionally, a heater is wound around the conduit 22 so that the conduit 2
Since 2 was heated, this was one of the causes of the decrease in the efficiency of the entire apparatus. An object of the present invention is to solve the above-mentioned problems of the related art, prevent water from condensing in the conduit 22 without lowering the efficiency of the entire device, and achieve a stable high fuel cell performance. A molecular fuel cell power generator is provided.

[0016]

That is, the polymer electrolyte fuel cell power generator of claim 1 of the present invention is humidified through a fuel gas humidification tank and an oxidant humidification tank such as hydrogen and air. A fuel cell that generates electricity using an oxidant such as air and hot water in the fuel gas humidification tank or hot water obtained by exchanging heat with the hot water in the oxidizer humidification tank is circulated to the fuel cell as cooling water. A polymer electrolyte fuel cell power generator having a cooling device for feeding, wherein at least a part of a conduit for supplying the humidified hydrogen to the fuel cell is a double tube heat exchanger, and the humidified hydrogen is used. Through the inner tube of this double-tube heat exchanger and the cooling water discharged from the fuel cell through the outer tube of the double-tube heat exchanger, thereby heating the above-mentioned pipeline and condensing water in the tube. To prevent The features.

The polymer electrolyte fuel cell power generator according to claim 2 of the present invention is the polymer electrolyte fuel cell generator according to claim 1, wherein the humidified hydrogen is used as cooling water discharged from the fuel cell. It is characterized by flowing so as to face each other.

In the polymer electrolyte fuel cell power generator of the present invention, at least a part of the conduit for supplying the humidified hydrogen to the fuel cell is a double tube heat exchanger, and the humidified hydrogen is Passing the inner tube of the heavy-tube heat exchanger and the cooling water discharged from the fuel cell through the outer tube of the double-tube heat exchanger, heats the conduit to condense water in the tube. Since it is prevented, a heater or the like is not required and the efficiency of the entire apparatus is not lowered, and water does not condense in the pipe of the pipe line even at the time of start-up, so that the start-up time can be shortened and stable and high. Fuel cell performance can be demonstrated. By flowing the humidified hydrogen so as to face the cooling water discharged from the fuel cell (countercurrent flow), the pipe line can be heated more efficiently, and the water can be prevented from condensing.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory view for explaining an embodiment of the polymer electrolyte fuel cell power generator of the present invention. FIG. 2 is a cross-sectional explanatory view schematically illustrating one embodiment of the cross section of the double-tube heat exchanger. In FIG. 1, the same components as those shown in FIG. 3 are designated by the same reference numerals, and a duplicate description will be omitted.

In the polymer electrolyte fuel cell power generator (PEFC device GS1) of the present invention shown in FIG. 1, hydrogen (reformed gas) humidified in the fuel gas humidifying tank 6 is supplied to the fuel electrode 1a of the fuel cell 1. A part of the pipe line 22 to be supplied is used as a double tube heat exchanger 24, and humidified hydrogen is supplied to the double tube heat exchanger 24.
Except that the pipe 22 is heated by passing the cooling water discharged from the cooling unit 1c of the fuel cell 1 through the inner pipe 24a of the fuel cell 1 and the outer pipe 24b of the double-tube heat exchanger 24. It is the same as the conventional polymer electrolyte fuel cell power generator (PEFC device GS) shown in FIG.

As shown in FIG. 1 and FIG.
In the EFC device GS1, the reformed gas humidified in the fuel gas humidifying tank 6 is supplied to the inner pipe 2 of the double pipe heat exchanger 24.
4a, and the cooling water (warm water) discharged from the cooling unit 1c of the fuel cell 1 is passed through the outer pipe 24b of the double-tube heat exchanger 24 so as to face (counterflow) with the flow of the reformed gas. This heats the conduit 22.

Whether the entire pipe 22 is the double pipe heat exchanger 24 or a part thereof is the double pipe heat exchanger 24, when the humidified reformed gas is passed through the pipe 22, It suffices to prevent water from condensing in the tube, and its structure, material, dimensions, etc. are not particularly limited. The double tube heat exchanger 24 shown in FIGS.
The double tube heat exchanger 24 and the pipe 22 are shown in FIG.
As an example of the material of SUS316, SUS316 can be cited.

The PEFC apparatus GS1 of the present invention is configured as described above, and uses the humidified reformed gas in the conduit 22.
Water does not condense in the pipe when it is supplied to the fuel electrode 1a of the fuel cell 1 through the pipe.

Even when the temperature of the conduit 22 is low at the time of starting the PEFC apparatus GS1 of the present invention, the humidified reformed gas is passed through the conduit 22 and the fuel electrode 1 of the fuel cell 1 is supplied.
Before being supplied to a, hot water in the fuel gas humidifying tank 6 or hot water obtained by exchanging a part of the hot water with the hot water in the oxidizer humidifying tank 7 through the pipe 21 is previously supplied to the pipe 20. After that, the fuel cell 1 is supplied to the cooling unit 1c, and, for example, the fuel cell 1 is preheated to bring the temperature inside the fuel cell 1 to a temperature suitable for power generation, and hot water discharged from the cooling unit 1c of the fuel cell 1 is supplied. Outer tube 24 of double tube heat exchanger 24
By heating the conduit 22 by passing it through b, it is possible to prevent water from condensing in the conduit even when the humidified reformed gas is passed through the conduit 22. After this, the humidified reformed gas is supplied to the fuel electrode 1a of the fuel cell 1 through the conduit 22, and the humidified reaction air is supplied to the air electrode 1k of the fuel cell 1 through the conduit 23. By doing so, the startup time can be shortened. Then, electricity is generated by an electrochemical reaction between hydrogen in the reformed gas supplied to the fuel electrode 1a and oxygen in the air supplied to the air electrode 1k.

In the above description of the embodiment, the example in which at least a part of the pipe line 22 is the double pipe heat exchanger 24 is shown.
Similarly, the humidified reaction air is supplied to the air electrode 1 of the fuel cell 1.
It is also possible to use the double-pipe heat exchanger as shown in FIG. 1 or FIG. When doing so, it is possible to prevent water from condensing in the pipe.

The above description of the embodiments is for explaining the present invention, and does not limit the invention described in the claims or reduce the scope thereof. Further, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.

[0027]

According to the first aspect of the present invention, there is provided a polymer electrolyte fuel cell power generation apparatus which oxidizes hydrogen and air that have been humidified through a fuel gas humidifying tank and an oxidant humidifying tank that has humidified hydrogen and air. And a cooling device for circulating hot water in the fuel gas humidifying tank or hot water obtained by adding hot water that has exchanged heat with the hot water in the oxidizer humidifying tank to the fuel cell as cooling water. A solid polymer electrolyte fuel cell power generator having the double-tube heat exchanger, wherein at least a part of the conduit for supplying the humidified hydrogen to the fuel cell is a double-tube heat exchanger. The cooling water discharged from the fuel cell through the inner pipe of the heat exchanger and the outer pipe of the double heat exchanger to heat the pipe and prevent water from condensing in the pipe. Because it was done before A heater provided in the pipeline is not necessary and the efficiency of the entire device is not reduced. It is possible to prevent water from condensing in the pipeline at the time of start-up, and to shorten the start-up time. It has a remarkable effect that it can exhibit its performance.

The polymer electrolyte fuel cell power generator according to claim 2 of the present invention is the polymer electrolyte fuel cell generator according to claim 1, wherein the humidified hydrogen is discharged from the fuel cell as cooling water. Since it flows so as to face each other, it is possible to heat the pipe line more efficiently and to prevent water from condensing in the pipe.

[Brief description of drawings]

FIG. 1 is an explanatory view showing one embodiment of a polymer electrolyte fuel cell power generator according to the present invention.

FIG. 2 is a cross-sectional explanatory diagram schematically illustrating one embodiment of a cross section of a double-tube heat exchanger.

FIG. 3 is an explanatory diagram of a conventional polymer electrolyte fuel cell power generator.

[Explanation of symbols]

1 fuel cell 1a Fuel pole 1k air pole 1c Cooling unit 2, 10 heat exchanger 5, 15, 18 pumps 6 Fuel gas humidification tank 7 Oxidizer humidification tank 14 Solenoid valve 17 frames 20, 21, 22, 23 pipelines 24 Double tube heat exchanger 24a inner tube 24b outer tube GS, GS1 polymer electrolyte fuel cell power generator RD heat recovery device CD cooling device

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor, Seiichi Yoshida             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Taketoshi Koki             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F-term (reference) 5H026 AA06                 5H027 AA06 BA01 BA16 BA17 CC06                       DD06

Claims (2)

[Claims] 1. A fuel cell for generating power by an oxidant such as air humidified through a fuel gas humidification tank and hydrogen and an oxidant humidification tank such as air, and hot water in the fuel gas humidification tank or hot water thereof. A polymer electrolyte fuel cell power generator comprising: a cooling device that circulates and sends hot water to the fuel cell as cooling water by adding hot water that has undergone heat exchange with the hot water of the oxidizer humidifying tank, wherein the humidified At least a part of the conduit for supplying hydrogen to the fuel cell is a double-tube heat exchanger, and the humidified hydrogen is passed through the inner tube of this double-tube heat exchanger and the double-tube heat exchanger A polymer electrolyte fuel cell power generation device, characterized in that cooling water discharged from a fuel cell is passed through an outer pipe to heat the pipe to prevent water from condensing in the pipe. 2. The polymer electrolyte fuel cell power generator according to claim 1, wherein the humidified hydrogen is caused to flow so as to face cooling water discharged from the fuel cell.