JPH0377278A - Drainage system for fuel cell - Google Patents

Abstract

PURPOSE: To directly drain excessive water from a fuel cell to the outside by providing a water storage tank, a water purifying means, a purifying facility, a power part, a water circulating means communicated with storage tanks, and installing a means to drain water when the quantity of water in the water storage tank exceeds a prescribed amount. CONSTITUTION: Water in a water storage tank 6 is turned back to a cooling apparatus 4 of a driving part 2 after passing through a purifying facility 10. Excessive purified water is turned back to the tank 6. Steam in a exhaust gas of a negative electrode C of the power part 2 is condensed by a condenser 20 and flows into the tank 6. The exhaust gas from a positive electrode A is sufficiently humidified by produced water and dehumidified in the same manner and the resultant water flows in to the tank 6. When the water in the tank 6 reaches the level L in an upper part of a flowing-in tube 14, the amount of purified water flowing in is decreased. The water levels in the tank 6 and an uprighty standing pipe 24 becomes sufficiently high, the purified water in the pipe 24 is discharged to the outside of the apparatus through a drain pipe 28. Consequently, only purified water reaches to the water discharging pipe 28 and drained to the outside and the environments are not affected at all.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a power plant using a fuel cell.

More specifically, the present invention relates to a drainage device used in such a power plant.

[Prior Art] Water is produced as a byproduct of electrochemical reactions that occur within power plants using fuel cells. Since this reaction is exothermic, water is also used as a refrigerant in power plants to regulate the temperature of the battery. Steam is also used in operation within power plants to reform raw hydrocarbon fuels into hydrogen-rich fuels suitable for consumption within batteries.

Because water is produced and functions within the plant;
Power plants using fuel cells require the installation of a water circulation system that recovers, stores, purifies, and recirculates water via cooling equipment within the plant. Of this water,
The water vapor form is consumed by the power plant as the fuel is reformed, but in the general case more is produced within the plant by electrochemical reactions than is consumed by the plant in the water vapor form. There will be more water.

Therefore, it is necessary to periodically drain the water circulating in the power plant using the fuel cell and the water in the storage device.

[Problem to be solved by the invention] However, the water inside the fuel cell contains water that is contaminated with impurities such as ammonia, carbon dioxide, and corrosive substances from the equipment, and water that has been purified through filters and purification beds. Because it contains water, care must be taken to ensure that the wastewater from the plant is purified and free of impurities. From the viewpoint of environmental protection, it is necessary to suppress the degree of contamination of water discharged to the outside as low as possible.

That is, it is desirable to install a drainage device in the power plant that discharges only purified water within the device and operates automatically.

Therefore, it is an object of the present invention to drain excess water from a fuel cell directly to the outside. In addition, only the purified water in the blunt is drained. A further object is to provide a device that automatically drains water when the amount of water in the power plant exceeds a preset amount.

[Means for Solving the Problems] In order to achieve the above object, a power plant using a fuel cell according to the present invention is provided with a power section and a water circulation device for cooling the power section, and the water circulation device is , a water storage tank for storing water used in the apparatus, a purification means for purifying the water in the circulation device, and a first means for circulating water from the storage tank to the purification means. , a second means for circulating water from the purification means to the power section for cooling the power section; a third means for circulating purified water from the purification means to the storage tank; and a third means for circulating purified water from the purification means to the storage tank; fourth means for circulating water containing impurities from the storage tank to the storage tank; and a fourth means connected to the third means, for circulating water containing impurities through the third means when an amount of water in the storage tank exceeding a predetermined capacity is detected. It is formed from a drainage means that discharges only purified water.

The fourth means may include means for circulating impurity-containing cooling water from the power unit to the storage tank and condensing generated water from the exhaust gas of the cathode, and continuously circulating the condensed generated water to the storage tank. conduit means for addition to the cooling water in the storage tank.

Furthermore, the drainage means is connected to the third drain near the storage tank.
a drain pipe leading to the third means and engaged with the storage tank so that water flows from the third means through the drain pipe when the level of water in the storage tank exceeds a certain height; means connected to the drain pipe.

Note that the drainage means is further provided with a standpipe communicating with the third means and the drainage pipe, and the standpipe is arranged so that the water level in the storage tank is at the entrance to the tank of the third means. water is drawn up from the third means to the drain pipe when the water rises above the third means.

Alternatively, the drainage means may include a drainage pipe branching to an upstream portion of the water circulating from the purification means of the third means, and a drainage pipe branching to an upstream portion of the water circulating from the purification means of the third means, and a drain pipe branching to an upstream portion of the water circulating from the purification means of the third means; , and this reduced pressure selectively
Means is provided for drawing water circulating within the third means into the drainage pipe.

[Operation] A power plant using a fuel cell configured as described above stores recirculated cooling water and condensed water vapor in the plant in a storage tank, purifies this water with a purification device, and transfers it to the storage tank. After reaching a certain amount of water inside the plant, only this purified water is automatically discharged to the outside of the plant.

[Embodiments] Hereinafter, the features of the present invention described above will be specifically explained in detail in preferred embodiments with reference to the accompanying drawings.

FIG. 1 schematically shows a portion of a power plant that corresponds to the present invention. The plant includes a power section 2 that includes a fuel cell and in which the electrochemical reactions take place. The power unit 2 includes a cooling device 4 in which cooling water circulates to adjust the temperature of the battery.
has. The water storage tank 6 stores water mixed with carbon dioxide, ammonia, and equipment corrosive substances flowing from the cooling device 4 via a flow path 8.

The water in the storage tank 6 continuously flows from the storage tank 6 via the channel 9 towards a filter and purification device for purifying the water. The purified water that has passed through the purification device 10 returns to the cooling device 4 of the power unit 2 via the flow path 12. Excess purified water is also recirculated to the storage tank 6 via the flow path 14. The evacuation device from the storage tank 6 is designated by the number 16.

In addition to the water flowing from the cooling device 4, the storage tank 6
Water that is condensed from the gas exhausted from the cathode C in the power section 2 is also stored therein. The cathode exhaust gas contains water vapor consisting of product water produced by an electrochemical reaction. Water vapor in the cathode exhaust passes through channel 18 and reaches condenser 20 where it is condensed into water. The condensed water passes from the condenser 20 through the channel 22 to the channel 8 and flows into the storage tank. The dehumidified cathode exhaust gas is discharged from the condenser 20 to the outside through a flow path 21.

Finally, the exhaust gas from the anode A is sufficiently humidified by the produced water, the anode exhaust is similarly dehumidified, and the water therefrom is stored in the storage tank 6. The purified water is constantly recirculated to the storage tank 6 via the channel 14, and the impure water also flows into the storage tank 6 at a constant rate via the channel 8.

FIGS. 2 and 3 show a preferred embodiment of an automatic drainage control device that discharges only purified water. The purified water that has returned via the flow path t4 is supplied to the standpipe that reaches the storage tank 6 through the flow path 14 and the flow path 26. When the water level in the storage tank 6 is below the flow path 14,
As illustrated in FIG. 2, the purified water flows into the storage tank 6 via the flow path 14. Water mixed with impurities from the power section flows into the storage tank 6 from the direction of arrow B.

When the water in the storage tank 6 reaches a level L (indicated by a dotted line) above the area where purified water flows, the storage tank 6
The amount of purified water flowing into the tank is reduced.

As the water level rises within the tank, purified water rises within the standpipe 24. The drain pipe 28 extends from a position above the flow path 14 of the stand pipe 24 and below the flow path 26 . When the water level in the tank and in the standpipe 24 reaches a sufficient height as shown in FIG. be done. Therefore, only purified water reaches the drain pipe 28, and the present drainage device does not pose any environmental problems to the outside.

FIGS. 4 and 5 show a modified embodiment of a drainage device that discharges only purified water. In FIG. 4, the level of water in the storage tank 6 is below the tank inlet of the channel 14 into which purified water flows. The purified water is moving to the tank 6 through a flow path 14 as shown in the figure. In the purified water flow path 14,
A drainage branch 30 is installed to gradually move away from the flow path 14.

A pneumatic tube 32 leads to an upstream portion of the flow path 14 near the drainage branch 30 . This pneumatic tube 32 is
It has an open end 34 located below the purified water flow path 14 within the storage tank 6 . While the water level in the storage tank is below the open end 34 of the tube 32, the flow of purified water through the end of the tube 32 leading into the flow passage 14 will draw air out of the tank 6. tube 32
I'm drawn to it. This creates a positive pressure in the flow path 14 upstream of the drainage branch 30.

When the level of water in the tank 6 rises above the end 34 of the tube 32, air no longer flows from the tank 6 through the tube 32. As a result, the junction from the tube 32 in the purified water flow path 14 and the drainage branch 30
The pressure is reduced between. When this reduced pressure occurs, the flow of purified water flows along the walls of the channel 14 and out of the drainage branch 30. Purified water continues to drain out of the drain branch 30 while the end 34 of the tube 32 in the tank 6 is flooded.

[Effect of the invention 3 In the present invention, water from which inorganic substances have been removed by the purification device is returned to the storage tank, so that water that is not used in the cooling device is returned to the storage tank. Excess water will accumulate. Therefore, the amount of water in the entire device is indicated by the water level in the storage tank.

The present invention has a mechanism that detects when the water level in the storage tank reaches or exceeds a certain level. The water flow can be diverted to a drainage path that drains the water outside the plant. At this time,
The flow of impure water flowing into the tank is not obstructed, and impurities within the tank cannot reach the drainage path.

Therefore, the drainage device of the present invention functions automatically when necessary and can easily drain only purified water from the power plant.

Its structure is simple and it can operate without requiring any driving force.

This device can be easily installed in existing fuel cell-based power plants that require such characteristics.

The water discharged from the power plant can be disposed of directly outside without being reprocessed or repurified.

The application of the present invention is not limited to the illustrated embodiments, but may be implemented in all modifications without departing from the gist of the present invention as stated in the claims. .

[Brief explanation of drawings]

In the attached drawings, FIG. 1 is a schematic diagram of a water circulation system in a power plant using a fuel cell, and FIG. 2 is a side view of one embodiment when water is not discharged from the power plant by the drainage system according to the present invention. 3 is a side sectional view showing how water is discharged from the power plant during drainage in the same embodiment as in FIG. 2; FIG. FIG. 5 is a side sectional view showing the second embodiment when drainage is not being performed; FIG. 5 is a side sectional view showing how water is discharged from the power plant during drainage in the same embodiment as FIG. It is a diagram. 2...Power part 4...Cooling part 6...Storage tank IO...Purification device 16...Drainage device
2G...Capacitor 8.9, 12, 14, 18
．． 22...Flow path 24...Stand pipe 28...Drainage pipe 30...Drainage branch 32...Pneumatic tube 34.
・Open end

Claims (7)

[Claims] (1) It has a power unit and a water circulation device for cooling the power unit, and the water circulation device includes a water storage tank for storing water used in the circulation device, and purifies the water in the circulation device. a first means for circulating water from the storage tank to the purification means; and a second means for circulating water from the purification means to the power section for cooling the power section. a third means for circulating purified water from the purifying means to the storage tank; a fourth means for circulating water containing impurities from the power section to the storage tank; and the third means. A fuel cell is used, characterized in that the fuel cell is connected to a drainage means and discharges only the purified water flowing to the third means when the amount of water in the storage tank exceeding a predetermined capacity is detected. power plant. (2) The fourth means circulates impurity-containing cooling water from the power unit to the storage tank, and circulates generated water obtained by condensing cathode exhaust to the storage tank to continuously cool the storage tank. 2. A fuel cell power plant according to claim 1, further comprising conduit means for adding water. (3) The drainage means is located near the third storage tank.
a drain pipe leading to the third means, which engages the storage tank and causes water to flow from the third means through the drain pipe when the level of water in the storage tank exceeds a preset height. 3. A power plant using a fuel cell according to claim 1 or 2, characterized in that it comprises means for fluidly connecting to said drainage pipe. (4) the drainage means further includes a standpipe communicating with the third means and the drainage pipe, the standpipe being such that the water level in the storage tank is at the entrance to the tank of the third means; 3 above, when the rise is higher than
4. The power plant using a fuel cell according to claim 3, wherein the power plant operates to draw water from the means to the drain pipe. (5) The drainage means includes a drainage pipe branching to an upstream portion of the water circulating from the purification means of the third means;
1 or 2, wherein a reduced pressure is created in the means of the third means, said reduced pressure optionally comprising means for drawing water circulating in said third means into said drain pipe. A power plant using the fuel cell according to item 2. (6) The power plant includes a fuel cell power section having a cathode side and a cooling section using water or a refrigerant, a water storage tank, a purification means through which a water flow path passes, and a cooling section of the power section that connects the a flow path for circulating impurity-containing water to a storage tank; a flow path for circulating water from the storage tank to the purification means; and a flow path for circulating excess purified water from the purification means to the storage tank. At the same time, a flow path for circulating the purified water from the purification means to the entrance side of the cooling section, and a flow path for periodically discharging a portion of the excess purified water when the amount of water in the storage tank exceeds a certain amount. From a cooling water path in a power plant using fuel cells, characterized in that it comprises at least one section for diverting the flow of excess purified water from the purification means into a drainage pipe for drainage outside the plant. A method of draining excess water to the outside of the power plant. 7. The method of claim 6, further comprising the steps of: (7) condensing product water from the cathode exhaust gas; and a flow path for conveying the condensed product water to the storage tank.