JPS6180766A - Power generation plant of fuel cell - Google Patents

Abstract

PURPOSE:To make the good control of a differential pressure between poles possible, by keeping a flow control valve set between the discharge exit of a compressor and the air pole exit of a fuel cell under the switching control in proportion to the pressure deflection between an air pole and a fuel pole. CONSTITUTION:A flow control valve (14) is set in place inside a pipe (13), setting the pipe (13) penetrating between the discharge exit of a compressor (2) and the air pole exit of a fuel cell (1). When the pressure of the air pole becomes lower than that of the fuel pole, pressure deviation (c) has some positive value and an adjuster (17) issues a command to make a flow control valve 14 open as a signal (d) on the basis of the value. As the result, an air flow flowing through the pipe (13) increases and the air flowing through a pipe (9) increases by the amount. The amount increased in the air flow of the pipe (9) connects with the pressure loss increased in the pipe (9) and, as the result, keeps the pressure of the air pole higher and suppresses the differential pressure between the poles of the cell. Inversely, when the pressure of the air pole is higher than that of the fuel pole, the pressure of the air pole is kept lower and the differential pressure between the cell poles is suppressed as well.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a first fuel cell power generation plant, and more particularly, to a first fuel cell power plant, and more particularly, to a first fuel cell power plant, a first fuel cell (and a fuel cell having an air electrode), and a second fuel cell for supplying fuel to the fuel electrode. a fuel source for supplying air to the anode; means for regulating the supply fuel flow G from this fuel source to the anode; a compressor for supplying air to the cathode; and a supply air from the compression chamber to the cathode. A means for adjusting the flow rate, a turbine for driving the compressor, and a means for mixing the υV output air from the air electrode and the exhaust fuel from the fuel electrode and supplying the mixture to the front side turbine as driving energy. The present invention relates to a fuel cell power generation plant equipped with a fuel cell power generation plant.

[Technological disadvantages of inventions and their problems]

In the cell body of a fuel cell power generation plant, that is, in the fuel cell itself, the cell electrolyte membrane ruptures when the pressure difference between the fuel electrode and the air electrode (hereinafter referred to as interelectrode pressure difference) reaches approximately 0.1 atmosphere. This may lead to damage to the battery body.

Therefore, in the fuel cell power generation plans 1 to 1, a system configuration that suppresses the differential pressure between the electrodes as much as possible is required.

Conventionally, this requirement has been met with system configurations that are mainly divided into two types.

A first conventional example is the configuration shown in FIG.

The fuel electrode of the fuel cell 1 is supplied with fuel, such as hydrogen, whose flow rate has been adjusted through a flow rate control valve 6 from a fuel source (not shown). Fuel ratio i'li! Compressor 2 is installed on the air pole of 1.
A regulated air flow m is supplied from the air flow control valve 7 through the flow control valve 7. The compression section 2 is driven by a turbine 3. Air discharged from the air electrode of the fuel cell 1 is introduced into the mixer 5 via a pipe 9.

On the other hand, the fuel discharged from the fuel cell 1 is used as combustion fuel in the reformer 4, and then is sent to the mixer 5 through the pipe 10 in the same way as the discharged air, where the discharged air is The system exhaust gas from the mixer 5 is supplied to the turbine 3 as driving energy.
The discharge port of the compressor R2 and the mixer 5 are communicated via a control valve 8 in order to bypass excess air of the compressor R2.

The configuration shown in FIG. 3 is as follows:
to the pipe 9, and from the fuel electrode of the fuel cell 1 to the mixer 5.
By minimizing the resistance of each piping 10 up to the piping 10, the pressure loss in each piping is reduced and the differential pressure between poles is suppressed. In other words, in the mixer 5, which is the confluence point of both the fuel and air systems, the pressures of both systems are forced to be equal.
Therefore, the theory is that if each pressure loss in the pipes 9 and 10 is minute, the differential pressure between the poles corresponding to the difference in pressure loss between the two systems will also be small.

A second conventional example is the configuration shown in FIG.
1. The feature of this configuration is based on the system configuration shown in Fig. 3, in which a pressure control valve 11 is provided in the pipe 9 on the air electrode outlet side, and a pressure control valve 12 is provided in the pipe 10 on the fuel (stile outlet side). The pressure control valves 11 and 12 respectively control the pressure at the fuel electrode and the air electrode of the fuel cell 1, that is, the pressure from the fuel cell 1 to the mixer 5 in both systems. This configuration attempts to prevent the generation of a large differential pressure between poles by making it possible to adjust the piping resistance of each piping 9, 10.

However, in the system configuration shown in Figure 3, it is impossible to completely reduce the piping resistance of both the air and fuel systems from the fuel cell 1 to the mixer 5, that is, the piping pressure loss, so the A differential pressure between the poles is generated, which corresponds to the difference in pipe pressure loss. Naturally, this pressure difference between poles becomes larger in plants with large piping resistance.

Furthermore, in the system configuration J3 shown in Fig. 4, the pressure difference between the poles C3I can be reduced to almost zero using the pressure control valves 11 and 12, but the piping resistance of each piping, that is, the piping repulsion jO loss increases. , malfunction of the pressure control valves 11 and 12 leads to the risk of sudden pressure difference between poles, the pressure difference from the discharge port of the compressor n2 to the turbine 30 population increases, and the energy required for the turbine drive CJ increases. There are drawbacks such as. In particular, the last-mentioned increase in energy leads to a decrease in the efficiency of the entire plant.

Based on the above, it was desired to reduce the piping resistance from the fuel cell to the confluence of both fuel and air, and to suppress the differential pressure between the poles without reducing the overall efficiency of Plan 1. .

[Purpose of the invention]

Therefore, an object of the present invention is to provide a fuel cell power generation plant that can satisfactorily suppress the differential pressure between the poles without reducing the overall efficiency of the plant, and can avoid the sudden occurrence of the differential pressure between the poles due to malfunction. There is a particular thing.

(Summary of the Invention) To achieve this object, the present invention provides a fuel cell power generation plant mentioned at the beginning, including a pipe that communicates between the discharge port of the compressor and the air electrode outlet of the fuel cell, and a flow rate control valve inserted in the fuel cell; The present invention is characterized by further comprising means for controlling opening and closing of the flow rate control valve in a direction in which the difference decreases.

[Embodiments of the invention]

FIG. 1 shows an embodiment of the present invention.

In the diagram? ? rn1 to rn10 correspond to FIG. The feature of this embodiment is that a pipe 13 is provided which communicates between the discharge port of the compression R2 and the air electrode outlet of the fuel cell 1.
This is because a flow control valve 14 is disposed inside. The flow rate control valve 14 is controlled based on a signal C of the deviation between the fuel electrode pressure detected by the pressure detector 15 and the air electrode pressure detected by the pressure detector 16, which is output from the regulator 17. This is done by a command signal d.

If the air electrode pressure becomes lower than the fuel electrode pressure, the pressure leakage C has a positive value, and based on this, the regulator 17 opens the flow m control valve 14 as a signal d. Issue direction commands. As a result, the amount of air flowing through the piping 13 increases, and the amount of air flowing through the piping 9 also increases by this increase. This increase in the air flow rate in the pipe 9 leads to an increase in the pressure loss in the pipe 9, resulting in an increase in the pressure at the air electrode, which has the effect of suppressing the differential pressure between the battery electrodes. Conversely, when the air electrode pressure becomes higher than the fuel electrode pressure, the pressure width difference C becomes negative, and based on this, the regulator 17 outputs a signal d as the flow rate m.
A command to close the control valve 14 is issued. As a result, the amount of air flowing through the pipe 13 is reduced, and the amount of air in the pipe 9 is reduced by the amount of the reduction.

This reduction in the amount of air reduces the pressure loss in the pipe 9, and as a result, the pressure at the air electrode is lowered, and the differential pressure between the battery electrodes is also suppressed.

The embodiment of the present invention (Fig. 1) and the conventional device (Fig. 3)
Figure 2 shows a comparison of the response of the differential pressure between poles when the load suddenly changes.

Here, the solid line e is the interelectrode differential pressure response of the conventional system @ (Fig. 3) when the load suddenly changes at time t1, and the break 11f is:
Similarly, it is the interelectrode differential pressure response of the device of the present invention (FIG. 1).

As shown in the figure, according to the present invention, the inter-electrode pressure difference can be suppressed more effectively by the action of the flow rate control valve 14. In addition, in the conventional device shown in FIG. 4, malfunction of the pressure control valves 11 and 12 leads to the sudden generation of differential pressure between poles, whereas in the present invention, even if the flow control valve 14 malfunctions, the associated piping The air flow rate fluctuation of 13 only affects the differential pressure between the channels, and the generation of a large and sudden differential pressure is avoided.The device of the present invention also As a result, the pressure difference between the discharge port of the compression hoe 2 and the inlet of the turbine 3 is smaller (7), thereby making the system as a whole energy-saving.

As described above, the device of the present invention can be said to eliminate both of the drawbacks of the conventional examples shown in FIGS. 3 and 4, and has the advantages of both.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to satisfactorily suppress the differential pressure between the poles, and to avoid the sudden occurrence of the differential pressure between the poles due to malfunction of the flow control valve, that is, the flow rate control means. can do. Furthermore, the entire system can be configured to be energy-saving, that is, highly efficient.

[Brief explanation of the drawing]

Fig. 1 is a system diagram showing an embodiment of the present invention, Fig. 2 is a characteristic diagram comparing the 8i differential pressure response when the load suddenly changes between the device of the present invention and a conventional example, Figs. The figure is a system diagram of different conventional fuel cell power generation plants. DESCRIPTION OF SYMBOLS 1...Fuel cell, 2...Compressor, 3...Turbine, 4...Reformer, 5...A combiner, 6...Fuel flow control valve, 7...Air Flow ffi fIII lit valve, 8...Air circulation control valve, 9゜10.13...Piping, 14...Air circulation control valve, 15゜16...Pressure detector, 17...Adjuster . Applicant's agent Kiyoshi Inomata 1 Figure 62 Prisoner 3 Figure h 4 Concave

Claims (1)

[Scope of Claims] A fuel cell having a fuel electrode and an air electrode, a fuel source for supplying fuel to the fuel electrode, means for adjusting the flow rate of fuel supplied from the fuel source to the fuel electrode, a compressor for supplying air to the air electrode; means for adjusting the flow rate of air supplied from the compressor to the air electrode; a turbine for driving the compressor; exhaust air from the air electrode and the fuel. A fuel cell power generation plant comprising: a means for mixing exhaust fuel from an electrode and supplying the mixture to the turbine as driving energy; a pipe communicating between a discharge port of the compressor and an outlet of the air electrode; A flow rate control valve inserted in the piping, a differential pressure detection means for detecting a pressure deviation between the air electrode and the fuel electrode, and the pressure leakage is determined according to the detected output of the differential pressure detection means A fuel cell power generation plant characterized by comprising means for controlling opening and closing of the flow control valve in the direction of decreasing flow rate.