JP2007128784A - Fuel cell power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell power generator in which a humidified oxidizer gas can be well sent out to a fuel cell without providing a heating means such as a heater, and which can be miniaturized. <P>SOLUTION: A collected water tank 7 to collect moisture from discharged air is provided, a humidifier 6 to humidify a fuel gas and the oxidizer gas is housed in the collected water tank 7, and the humidifier 6 and its output side piping 6a are kept warm by heat of the discharged air introduced into the collected water tank to prevent the temperature drop of the output side piping 6a of the humidifier 6. A cooling water tank 8 to cool a fuel cell 5 is disposed below the collected water tank 7, and thereby, collected water is forced to flow into the cooling water tank 8 without using a pump. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel cell power generator that generates power using a polymer electrolyte fuel cell.

In a fuel cell power generator using a polymer electrolyte fuel cell, both a fuel gas containing hydrogen and an oxidant gas are humidified and supplied to the fuel cell in order to satisfactorily perform an electrochemical reaction. For example, in Patent Document 1, a recycle loop is provided in both the fuel gas discharge system and the oxidant gas discharge system, and humidification is performed by a bubbler system to stably supply the reaction gas.
Further, various controls such as maintaining the fuel cell temperature at a predetermined temperature are performed in order to maintain stable power generation. For example, in Patent Document 2, water vapor is recovered from the discharged air to humidify the supply air. A humidifier is used to heat and humidify the supplied air without separately providing water or a heating device.

JP-A-5-94832 JP 2005-251759 A

However, the above-described conventional fuel cell power generator tends to cause condensation due to a decrease in the temperature of the output-side piping of the humidifier, and the occurrence of this condensation causes a flooding phenomenon, so it has to be removed. For this reason, a heat source such as a heater is required, the overall efficiency is lowered, and temperature control is required, so a temperature sensor and a temperature control device are also required. Moreover, although the structure of patent document 2 can humidify fuel air efficiently, there were many components and a large space was required.
Accordingly, in view of such problems, the present invention provides a fuel cell power generator that can satisfactorily send humidified oxidant gas to a fuel cell without providing a heating means such as a heater, and can be further downsized. The purpose is to do.

In order to solve the above-mentioned problems, the invention described in claim 1 is a fuel cell power generator including a fuel cell that generates electric power by electrochemically reacting a fuel gas containing hydrogen and an oxidant gas. And a recovery water tank for recovering moisture from the exhaust gas after the reaction of the oxidant gas, and a humidifier for humidifying the fuel gas and the oxidant gas are accommodated in the recovered water tank, and the humidifier and its output side piping are provided. It is characterized in that it is kept warm by the heat of the exhaust gas introduced into the recovered water tank.
With this configuration, the humidifier is kept warm including the output side pipe, so that the temperature of the pipe can be maintained without providing a separate heat keeping means, and the occurrence of condensation can be prevented. Therefore, there is no need for a temperature control device for that purpose, and the device can be simplified. Further, since no energy is required for heat insulation, the power generation efficiency can be increased, and the humidifier is installed in the recovery water tank, so that the entire apparatus can be downsized.

The invention of claim 2 is the invention of claim 1, further comprising a cooling water tank for cooling the fuel cell, wherein the water recovered in the recovered water tank is supplied to the cooling water tank. To do.
With this configuration, it is possible to reduce the replenishment of water into the cooling water tank with tap water or the like, and it is possible to reduce the energy for raising the temperature of the cooling water to a predetermined temperature.

According to a third aspect of the invention, in the invention of the first or second aspect, the humidifier is supplied with cooling water used for cooling the fuel cell, and the fuel gas and the oxidant gas are humidified by the cooling water. Features.
With this configuration, since humidification is performed with warm water, it is not necessary to separately provide a device for heating the fuel gas and the oxidant gas, and power for that purpose can be saved.

According to a fourth aspect of the present invention, in the invention of the third aspect, the cooling water tank is arranged at a position lower than the recovered water tank.
With this configuration, the cooling water tank can be supplemented with cooling water without using liquid supply means such as a pump, and the apparatus can be simplified.

  According to the present invention, since the humidifier is kept warm by the exhaust gas on the air side including the output side pipe, it is not necessary to provide a separate heat keeping means, and no device for temperature control is required, thereby simplifying the device. Can do. Moreover, since no energy is required for heat insulation, the power generation efficiency can be increased, and the humidifier is installed in the recovery water tank, so that the entire apparatus can be downsized.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. FIG. 1 shows an example of an embodiment of a fuel cell power generator according to the present invention, and shows a home power generator equipped with a hot water storage tank for storing hot water. In FIG. 1, 1 is a fuel cell power generator, 2 is a hot water storage tank for storing hot water for use at home, and 3 is a circulation pump for heating hot water.

  The fuel cell power generator 1 includes a solid polymer fuel cell 5, a humidifier 6 that humidifies air (hereinafter referred to as fuel air) that is an oxidant gas supplied to the fuel cell 5, and recovers moisture from the air-side exhaust gas. A recovered water tank 7 for cooling, a cooling water tank 8 for cooling the fuel cell 5, a heat exchanger 9 for cooling the cooling water heated through the fuel cell 5 and heating the hot water in the hot water tank 2, , Referred to as exhaust air), a heat exchanger 10 for further heating the hot water, a circulation pump 11 for circulating the cooling water, and an electromagnetic valve 12 are provided. Similarly, the fuel gas containing hydrogen is humidified by the humidifier 6 and supplied to the fuel cell, and the exhaust gas is used for heating the reformer, but the entire circulation path of the fuel gas is omitted. is there.

  The recovered water tank 7 and the fuel cell 5 are installed close to each other, the humidifier 6 is disposed in the recovered water tank 7, and the output side pipe 6 a of the humidifier 6 is connected in the recovered water tank 7. The fuel cell 5 is connected. The cooling water tank 8 is installed at a position lower than the recovered water tank 7, and the water accumulated in the recovered water tank 7 is configured to naturally flow into the cooling water tank 8 by opening the electromagnetic valve 12.

  Next, the flow and operation of the fuel air and the cooling water of the fuel cell power generation apparatus having the above configuration will be specifically described. First, air in the atmosphere is taken into the humidifier 6. The water for humidifying the fuel air taken in by the humidifier 6 (including the humidification of the fuel gas) is the cooling water circulating to cool the fuel cell 5 and immediately after being used for cooling. Hot water is used. The cooling water near the outlet of the fuel cell 5 (point A in the figure) is substantially the same temperature as the set temperature of the fuel cell 5, and this hot water is introduced into the humidifier 6. The humidifier 6 humidifies the air with the hot water and simultaneously raises the temperature of the fuel air.

Similarly, the exhaust air after reaction discharged from the fuel cell 5 is also discharged at substantially the same temperature as the fuel cell (point B in the figure). Since this exhaust air includes water generated by a chemical reaction in the fuel cell 5 while being humidified by the humidifier 6, it contains a large amount of water. For this reason, the exhausted air guided to the recovered water tank 7 comes into contact with the recovered water having a temperature somewhat lower than that of the fuel cell 5, so that a large amount of water is separated and recovered in the recovered water tank 7.
As a result, the temperature of the recovered water in the recovered water tank 7 is kept constant at a temperature slightly lower than the fuel cell 5 by the heat of the exhaust air and the cooling water of the fuel cell 5, and the fuel cell from the humidifier 6 and the humidifier 6. The output side pipes 6 a up to 5 are also kept at a constant temperature close to the fuel cell 5.

The exhaust air from which moisture has been recovered in the recovered water tank 7 is cooled through the heat exchanger 10 and released into the atmosphere. At this time, the hot water in the hot water tank 2 circulated by the circulation pump 3 through the heat exchanger 10 is heated by the exhaust air, and the hot water in the hot water tank 2 maintains a high temperature state.
Further, the circulating cooling water sent out from the cooling water tank 8 is mixed with the air when passing through the humidifier 6 in the middle of the circulation (mixed with the fuel gas by passing through the humidifier that humidifies the fuel gas). Although it decreases, the hot water recovered in the recovered water tank 7 is supplied to the cooling water tank 8 by opening and closing the electromagnetic valve 12, and the cooling water is replenished. However, when the hot water in the recovered water tank is insufficient, the cooling water is supplemented with tap water or the like.

Thus, since the humidifier is kept warm including the output side pipe, the temperature of the pipe can be maintained without providing a separate heat keeping means, and the occurrence of condensation can be prevented. Therefore, there is no need for a temperature control device for that purpose, and the device can be simplified. Further, since no energy is required for heat insulation, the power generation efficiency can be increased, and the humidifier is installed in the recovery water tank, so that the entire apparatus can be downsized.
Furthermore, since the recovered water is returned to the cooling water tank, replenishment of water to the cooling water tank with tap water or the like can be reduced, and the cooling water tank is made lower than the recovered water tank, so that the liquid supply means such as a pump is not used. The cooling water tank can be replenished with cooling water only by opening and closing the valve, thus simplifying the apparatus.
In addition, since fuel gas and oxidant gas are heated when humidified, there is no need to heat them separately, and it is possible to save equipment and power for that purpose, and warm water is returned to the cooling water tank so that the cooling water is heated to a predetermined temperature. Less energy is required and energy efficiency can be increased.

It is a lineblock diagram showing an example of an embodiment of a fuel cell power generator concerning the present invention.

Explanation of symbols

  1 .... Fuel cell power generation device, 2 .... Hot water storage tank, 5 .... Fuel cell, 6 .... Humidifier, 6a ... Output side piping, 7 .... Recovery water tank, 8 .... Cooling water tank.

Claims (4)

A fuel cell power generator including a fuel cell that generates electric power by electrochemically reacting a fuel gas containing hydrogen and an oxidant gas,
It has a recovered water tank that recovers moisture from the exhaust gas after the reaction of the oxidant gas, and a humidifier that humidifies the fuel gas and oxidant gas is housed in the recovered water tank, and the humidifier and its output side piping are recovered. A fuel cell power generation apparatus that retains heat by heat of exhaust gas introduced into a water tank. The fuel cell power generator according to claim 1, further comprising a cooling water tank for cooling the fuel cell, wherein the water recovered in the recovered water tank is supplied to the cooling water tank. The fuel cell power generator according to claim 1 or 2, wherein cooling water used for cooling the fuel cell is supplied to the humidifier, and the fuel gas and the oxidant gas are humidified by the cooling water. The fuel cell power generator according to claim 3, wherein the cooling water tank is arranged at a position lower than the recovered water tank.

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