JPH02126568A - Fuel cell power generation device - Google Patents

Abstract

PURPOSE:To make it possible to remove impurities at a low cost by leading the cooling water of a direct contact type impurity removing device from a cooling water loop, and leading the cooling water released from the cooling water loop to the upper stream side of a water purifying system. CONSTITUTION:A water purifying device 7 to purify the cooling water is provided on the way of the cooling water loop of a cooling plate 4, and furthermore, a direct contact type impurity removing device 10 to contact directly the fuel electrode gas and the cooling water in a sufficient time is provided on the way of a fuel electrode gas feeding pipe 9 to feed the fuel electrode gas to a fuel electrode 2 of a cell main body 1. The cooling water of the direct contact type impurity removing device 10 is led from the cooling water loop, and the cooling water released from the loop is led to the upper stream side of a water purifying system 7. After the cooling water is purified in the water purifying device 7, a part of the cooling water is led to the cooling plate 4, and a part of it is delivered to the direct contact type impurity removing device 10 again to be circulated to contact to the fuel electrode gas. Consequently, impurities can be removed at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a fuel cell power generation device with an improved cooling water loop.

(Conventional technology) Fuel cell power generation devices are attracting attention due to their high efficiency and low emissions of harmful substances that have a negative impact on the environment.They are also expected to make effective use of waste heat. This is a power generation system.

A fuel cell sends hydrogen-rich gas or raw fuel to the fuel electrode, and air to the air electrode, and through an electrochemical reaction,
It is configured to generate DC power by reacting hydrogen and oxygen.

(Problem to be Solved by the Invention) Hydrogen-rich gas used in fuel cells contains various impurities depending on the raw fuel or manufacturing method used to produce the gas, and some of these impurities affect the characteristics of the fuel cell. or shorten the lifespan. Therefore, an inexpensive device for removing harmful impurities from gas has been desired.

The object of the present invention is to remove impurities in a hydrogen-rich gas by contacting the water with water, and to pass the water containing trace amounts of impurities through a water purification device in a battery cooling water loop, thereby reducing the cost of water. It is an object of the present invention to provide a fuel cell power generation device that can fully utilize the capabilities of a fuel cell main body by removing impurities.

[Structure of the invention]

(Means for Solving the Problems) The fuel cell power generation device of the present invention includes a fuel cell main body configured by stacking a fuel electrode and an air electrode, and an external cooling water loop provided for cooling the fuel cell main body. a magnetic plate to which cooling water is supplied from the cooling plate, a water purification device for purifying the cooling water is provided in the middle of the cooling water loop of the cooling plate, and further sends fuel electrode gas to the fuel electrode of the fuel cell main body. A direct contact type impurity removal device is provided in the middle of the fuel electrode gas supply pipe to bring the fuel electrode gas and cooling water into direct contact with each other for a sufficient residence time, and the cooling water for this direct contact type impurity removal device is supplied from the cooling water loop. The cooling water discharged therefrom is characterized in that it is guided to the upstream side of the water purification system.

(Function) In the present invention, impurities in the gas are removed into the water by contacting the cooling water for a sufficient residence time when the fuel electrode gas passes through the direct contact type impurity removal device. Furthermore, after this cooling water is purified by a water purification device, a portion of it is dedicated to the cooling plate, and a portion of it is sent again to the direct contact type impurity removal device and is passed through the W4 ring to contact the fuel electrode gas. It will be done.

(Embodiments) The present invention will be described below with reference to embodiments shown in FIGS. 1, 2, and 3. In each drawing, the same reference numerals indicate the same parts, so a description thereof will be omitted.

In the embodiment shown in FIG. 1, a fuel cell main body 1 is composed of a fuel electrode 2 and an air electrode 3. As shown in FIG. The drawing shows fuel electrode 2.
Although only one set of the air electrode 3 and the air electrode 3 are shown, a practical scale fuel cell main body is constructed by stacking many sets of these. Furthermore, in order to remove heat generated from the battery body 1, the battery body 1 is constructed by having a large number of cooling plates 4, and arranging these fuel electrodes 2, air electrodes 3, and cooling plates 4 inside the body la. There is.

Further, in the present invention, the cooling plate 4 of the fuel cell main body 1 is supplied by the pump 5. A cooling method that uses cooling water is used. That is, the cooling water supplied from the pump 5 is supplied to the battery main body inlet, passes through the cooling plate 4, cools the battery main body 1, and is then discharged from the battery main body outlet, passes through the heat exchanger 6, and returns to the pump 5. return. The temperature of the cooling water is controlled by the heat exchanger 6 to an appropriate temperature for cooling the battery body 1. Further, a part of the cooling water sent out from the pump 5 is sent to the water purification device 7 via the heat exchanger 8, and returns to the pump 5 again after the water quality is purified.

The fuel electrode gas supplied from the fuel electrode gas supply pipe 9 is first guided to a direct contact type impurity removal device 10, purified there, and then sent to the fuel electrode 2. The gas that has undergone an electrochemical reaction at the fuel electrode 2 is discharged from the outlet pipe 11, but a part of it may be recirculated by the blower 12.

Thus, the direct contact type impurity removal device 10 provided according to the present invention is configured so that the fuel electrode gas and the cooling water purified by the water purification device 7 come into direct contact for a sufficient residence time. The discharged water is again sent to the water purification device 7 via the heat exchanger 8 by the pump 13. A cooling water outlet pipe 17 is provided in the cooling water loop including the cooling plate 4 and the direct contact type impurity removal device 10.

Air is also supplied from the supply pipe 14 and sent to the air electrode 3 of the fuel cell main body 1. The gas that has undergone an electrochemical reaction at the air electrode 3 is discharged from the outlet pipe 15, but a part of it may be recirculated by the blower 16.

Next, the operation of the fuel cell power generating apparatus of the present invention configured as described above will be explained. Fuel electrode 2 and air electrode 3 of battery body 1
In this case, hydrogen and oxygen react through an electrochemical reaction of the feed gas, producing water or steam and extracting a direct current output. Heat generated in the battery body 1 is discharged by water passing through the cooling plate 4. In order to maintain the temperature of the battery body 1 within an appropriate temperature range, the temperature of the cooling supplied to the battery body 1 by the heat exchanger 6 is controlled.

The water flowing out of the battery body 1 may be a liquid or a single-phase flow of only water depending on the design concept, or may be a two-phase flow of water vapor or a gas-liquid mixed flow of water.
Sometimes it is a phase flow. Although FIG. 1 is shown as a suitable cooling loop configuration for single-phase flow, the operation of the invention does not change when considered for two-phase flow. However, some modifications (not shown) may be required for the cooling loop.

In the cooling water system of the fuel cell power generation device of the present invention, in order to prevent or correct deterioration of the quality of the cooling water, a water purification device 7 is provided to circulate a part of the battery cooling water to maintain the water quality. I have to. The heat exchanger 8 controls the temperature so that the water purification device 7 operates appropriately. A portion of the water sent out from the water purification device 7 is sent to the direct contact type impurity removal device 10 and comes into contact with the fuel electrode gas. The excess cooling water in the cooling water loop is discharged from the cooling water wetting pipe 17 to maintain the cooling water loop in an appropriate state.

The fuel electrode gas may be M fuel gas, but in FIG. 1, hydrogen-rich gas is assumed.

The fuel electrode gas contains impurities due to its manufacturing method and raw fuel components, some of which may deteriorate the characteristics of the battery body 1. Particular examples include ammonia and chlorine, which can be removed by contact with water. The direct contact type impurity removal device 10 is configured to provide sufficient contact time between the anode gas and water, and impurities dissolved in water are removed from the anode gas.

The water discharged from the direct contact impurity removal device 10 is sent by the pump 13 to the battery cooling water purification device 7, where it is purified and recirculated. By integrating the water purification device 7 in this manner, it is possible to reduce costs and prevent deterioration of battery characteristics.

Note that if the inlet temperature of the pump 13 is high, the pump 13
A heat exchanger (not shown) may be installed upstream of the inlet of the pump 13, and if the outlet temperature of the pump 13 is within an appropriate temperature range and matches the operating temperature of the water purification device 7, the heat exchanger 8 may be installed upstream of the inlet of the pump 13. It can also be done without going through it.

The purified fuel electrode gas is supplied to the fuel electrode 2 and led out from the outlet pipe 11 after reaction. The blower 12 is the fuel electrode 2
In some cases, it operates in order to maintain the proper state.

Moreover, the air introduced from the air supply pipe 14 is air wA3
After being supplied to, it is led out from the lead-out pipe 15. Blower 1
6 may operate in order to maintain the condition of the air electrode 3 appropriately.

The use of the exhaust fuel gas discharged from the fuel electrode 2 differs depending on the configuration of the plant system. Although not shown, it can be used as a heat source for a reformer, for example, if there is one, or it can be fed into a combustor to drive a turbine or serve as a heat source for a boiler. On the other hand, the exhaust air discharged from the air electrode 3 is used in various ways by the plant system. Although not shown, for example, it may be put into a combustor and used as an oxygen source for combustion, or it may directly serve as a driving source for a turbine.

In this way, in the fuel cell power generation device of the present invention, impurities in the fuel electrode gas are removed by being dissolved in water by the direct contact type impurity removal device 10, thereby improving the performance of the battery body 1 and preventing deterioration of its life. can do. Further, impurities dissolved in the water are removed by a water purification device 7 installed in the battery cooling water system. In particular, impurities such as ammonia reduce BOD [biological oxygen demand fa:
(Biological Oxygen Demand
), so there are restrictions on discharging it as is, and removing it with water treatment equipment tends to increase the cost.

According to this embodiment, by using the water purification device 7 of the battery cooling water system to remove impurities, it can be constructed at low cost.

The fuel gas supplied from the fuel electrode gas supply pipe 9 may be reformed gas from a reformer not shown in the diagram, or it may be hydrogen generated from an electrolytic tank or the like in the two-dani industry. be. In the case of decomposed gas, nitrogen in the raw fuel is converted to ammonia and becomes an impurity, and in the case of hydrogen from an electrolytic tank, it may also contain a trace amount of ammonia as an impurity. In either case, the impurity is removed into the water by the direct contact type impurity removal device 10 of this embodiment, and then by the water purification device 7.

Next, in another embodiment of the present invention shown in FIG.
This is the same as the one shown in the figure, with a control valve and measuring device added for adjustment. That is, in FIG. 2, a flow rate control valve 20 and a flow rate measuring device 21 are provided in the cooling water line supplied from the water purification device 7 disposed in the cooling water system of the battery body 1 to the direct contact type impurity removal device 10, and further heat exchanger 2
2 and a temperature control valve 23, and a temperature measuring device 24 is provided. Further, a temperature measuring device 25 is provided to measure the temperature of the fuel electrode gas flowing out from the direct contact type impurity removing device 10.

The temperature signals measured by each temperature measuring device 24 , 25 are transmitted to a temperature control device 26 . The flow rate measured by the flow rate measurement device 21 is transmitted to the flow rate control device 27.

The temperature control valve 23 is activated by a control signal from the temperature control device 26.
and be transmitted to the flow rate control device 27.

The control signal from the flow rate control device 27 is transmitted to the flow rate control valve 20.
control.

Next, the operation of another embodiment shown in FIG. 2 will be explained.

It is desirable that the fuel N-electrode gas flowing out from the direct contact type impurity removal device 10 is maintained at a temperature specified by the operating state of the power generation system. The temperature may be specified to vary in response to the load on the power generation system;
In some cases, it is specified to hold it at a constant value. The temperature of the fuel electrode gas flowing out from the direct contact impurity removal device 10 is measured by a temperature measuring device 25, and
It is passed down to

Direct contact type impurity removal device 10 from the fuel electrode gas supply pipe 9
The amount of fuel electrode gas supplied to the fuel cell power generation system varies greatly depending on the load of the fuel cell power generation system.

Therefore, the temperature measured by the temperature measuring device 25 is controlled by the temperature and flow rate of the cooling water supplied to the direct contact impurity removal device 10. There are various ways to control this, such as keeping the temperature of the cooling water almost constant and changing the flow rate, keeping the flow rate of the cooling water almost constant and changing the temperature of the cooling water, or changing both the temperature and flow rate of the cooling water. For example, both may be kept almost constant. Which of these methods is selected depends on the requirements of the power generation system.

In the present invention, a flow rate control valve 20 and a flow rate measuring device 21 are provided as means for regulating the flow rate of cooling water, and a symbol from the flow rate measuring device 21 and a signal from the temperature control device 26 are sent to the flow rate controlling device 27. The signal from the flow control device 27 controls the flow control valve 20.

The operation of the fuel cell power generation apparatus of the present invention including the electrical control system shown in FIG. 2 will be explained. Cooling water temperature control is as follows. The signal measured by the temperature measuring device 24 and the signal measured by the temperature measuring device 25 are input to the temperature control device 26. The temperature control device 2G calculates and judges based on the relationship with the fuel electrode gas temperature designated by one power generation plant, issues a signal, adjusts the cooling water temperature control valve 23, and controls the heat exchanger 22. On the other hand, the signal from the temperature control device 26 is sent to the flow rate control device 27 and used as one of the information.

Regarding the control valve 23 of the heat exchanger 22, although Fig. 2 shows a case where the control valve 23 is installed on the cooling water side, the same effect can be obtained by adjusting the fluid on the other side of the heat exchanger. be able to. Further, the temperature of the water purification device 7 is controlled by a heat exchanger 8. Although the control method is not shown, the method of controlling the temperature of the cooling water supplied to the direct contact type impurity removal device 10 described above can be applied.

Furthermore, when the control temperature of the water purification device 7 and the temperature adjusted by the cooling water temperature measuring device 24 are close to each other, and the temperature is allowed to fluctuate within the temperature fluctuation range adjusted by the fuel gas temperature measuring device 25, In this case, the cooling water heat exchanger 22 and the temperature control valve 23 can be omitted.

As described above, in the other embodiment of the present invention shown in FIG. 2, the temperature and flow rate of the cooling water can be controlled, and the temperature of the fuel electrode gas can be controlled within the range of values required by the power generation system. This removes impurities in the fuel electrode gas, prevents deterioration of the characteristics of the fuel cell body, and makes it possible to extend the life of the fuel cell at low cost.

Next, in the embodiment shown in FIG.
The direct contact type impurity removal device 10 shown in the figure is connected to a heat exchanger 30.
．． It is configured to substantially replace .31. Temperature control valves 32, 33 are provided, the signal of the temperature measuring device 34 is transmitted to the flow control device 36 and the temperature measuring device 35
The signal is transmitted to the temperature control device 37.

In the fuel cell power generation apparatus shown in FIG. 3, the fuel electrode gas supplied from the fuel electrode gas supply pipe 9 generally contains steam as one of its components.

This embodiment functions effectively when vapor is contained in this way. The supplied fuel electrode gas is transferred to heat exchanger 3
1 and then enters the condensing heat exchanger 30. A portion of the vapor in the fuel electrode gas condenses, and its impurities, such as ammonia and chlorine, easily dissolve in the condensed water. The condensed water is sent by the pump 13 to the water purifier 7 in the cooling water loop and purified. The temperature of the condensing heat exchanger 30 is measured by a temperature measuring device 34. The signal is transmitted to the flow control device 36, where it is calculated and determined, and the flow control valve 32 is adjusted according to the signal from the flow control device 36. As a result, the temperature of the condensing heat exchanger 30 is adjusted to an appropriate range required by the fuel cell power generation system, and impurities are also removed.

The fuel electrode gas flowing out from the condensing heat exchanger 30 is concentrated again in the heat exchanger 31, where it is reheated and guided to the fuel cell main body. The temperature of the heat exchanger 31 is measured by a temperature measuring device 35,
The signal is transmitted to the temperature control device 37 and subjected to calculation 9. The signal from the temperature control device 37 is sent to the temperature control valve 33.
is adjusted to control the temperature of the fuel electrode gas within an appropriate range, and is also transmitted to the flow rate control device 36.

With the configuration and operation shown in FIG. 3, impurities in the supplied fuel electrode gas can be appropriately removed and purified, and gas in an appropriate temperature range required by the fuel cell power generation system can be supplied.

In FIG. 3, if the temperatures controlled by the temperature measuring devices 34, 35 are close to each other, the heat exchanger 31 can be omitted, and therefore the temperature control valve 33. The temperature measurement device 35, temperature control device 37, etc. can be omitted.

Furthermore, although FIG. 3 shows a case where the cooling water to the condensing heat exchanger 30 is controlled by the flow rate control valve 32, the second
As shown in the figure, a similar effect can be obtained using a temperature control valve or a combination thereof. In addition, the cooling water itself to the condensing heat exchanger 30 may be used while partially circulating the cooling water from the cooling water loop of the battery main body, or it is possible to obtain the same effect by using another cooling water. can.

〔Effect of the invention〕

As described above, in the present invention, a water purification device is provided in the middle of the cooling water loop for the cooling plate of the fuel cell main body,
Furthermore, by providing a direct contact type impurity removal device in the middle of the fuel electrode gas supply pipe and guiding the cooling water discharged from this direct contact type impurity removal device to the upstream side of the water purification device, the cooling plate of the fuel cell main body The cooling water of the direct contact impurity removal device and the cooling water of the direct contact impurity removal device are drawn from the same cooling water loop, and in particular, the cooling water of the direct contact impurity removal device is configured to be circulated through the water purification device. Impurities in the polar gas are effectively removed, and the overall cooling water loop is simplified.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing one embodiment of the fuel cell power generation apparatus of the present invention, and FIGS. 2 and 3 are system configuration diagrams showing other different embodiments of the present invention. 1... Battery body 2... Fuel electrode 3... Air electrode 4... Cooling plate 5... Cooling water pump 6... Heat exchanger 7... Water purification device 8
... Heat exchanger 9 ... Fuel electrode gas supply pipe 10 ... Direct contact impurity removal device (8733) Representative patent attorney Yoshiaki Inomata (and one other person) Fig.

Claims (1)

[Claims] A fuel cell main body configured by stacking a fuel electrode and an air electrode, and a cooling plate provided to cool the fuel cell main body and supplied with cooling water from an external cooling water loop,
A water purification device for purifying the cooling water is provided in the middle of the cooling water loop of the cooling plate, and a fuel electrode gas and cooling water are further provided in the middle of the fuel electrode gas supply pipe that sends the fuel electrode gas to the fuel electrode of the fuel cell main body. A direct contact type impurity removal device is provided, in which the cooling water of the direct contact type impurity removal device is brought into direct contact with the water for a sufficient residence time, and the cooling water of the direct contact type impurity removal device is led from the cooling water loop, and the cooling water discharged from there is passed through the water purification system. A fuel cell power generation device characterized by being guided to the upstream side of.