JPS61188863A - Reactant gas supplying device for fuel cell power generating installation - Google Patents

Abstract

PURPOSE:To suppress unnecessary gas consumption thereby improve maintainability of reactant gas supplying device by supplying the reactant gas to be consumed in a fuel cell body from an auxiliary reactant gas supplying device of a small capacity separately installed, when the installation is out of power generation such as in the case of shut down or the like. CONSTITUTION:A hydrogen gas bomb 2 and an oxygen gas bomb 3 as reactant gases suppliers are pipe-connected with a fuel cell body 1 through reactnat gases supplying lines 4, 5 which supply fuel and oxidizing agent. The reactant gases are supplied into the cell by adjusting the gas pressure through pressure control valves 6. Meanwhile, separately from the reactant gas suppliers of of the bombs 2, 3, an auxiliary reactant gas generator 10 of a small capacity is pipe-connected with the branching lines 8, 9 led out from the lines 4, 5 in the device of the power generating installation. The reactant gases consumed in the fuel cell body 1 is supplied from the gas generator 10, while the installation is out of power generation such as in the case of the installation shut down or the like. With the above constitution, unnecessary gas consumption is suppressed and maintainability is improved at the reactant gas supplier device.

Description

[Detailed description of the invention] [Technical field to which the invention pertains]

The present invention relates to a reaction gas supply device for a relatively small-capacity fuel cell power generation facility used, for example, as an emergency power source.

[Prior art and its problems]

First of all, Figure 4 shows an overview of this type of conventional fuel cell power generation equipment. In Figure 0, 1 is the fuel cell body which is a stack of unit cells, and 2 and 3 are filled with pressurized reaction gases of hydrogen and oxygen, respectively. hydrogen cylinders and oxygen cylinders as reactant gas supply sources, each cylinder 2.3 being connected to a fuel supply line 4. The oxidizing agent supply line 5 is connected to the fuel cell main body 1 through piping. Note that 6 is a pressure regulating valve inserted in the reaction gas supply line. With this configuration, by supplying reactive gases of hydrogen and oxygen from the reactive gas supply source to the fuel electrode and oxidizer electrode of each unit cell that constitutes the fuel cell body, a power generation reaction is performed in the fuel cell body. As is well known, the electricity generated is output to the output terminal 7. Such fuel cells have excellent start-up characteristics that allow them to reach a predetermined output voltage and supply power to a load in just a few milliseconds after the start of operation. Therefore, fuel and oxidizer are constantly supplied to the fuel cell main body. By holding this, it is possible to instantly start generating power and supply power to the load by connecting the load to the fuel cell when necessary. Taking advantage of this characteristic, fuel cells have recently come to be used as emergency power sources such as uninterruptible power supplies. However, when using fuel cell power generation equipment as an emergency power source, if the reactant gas supply state is maintained at all times, including when power generation is stopped, the following problems arise. In other words, (1) in a fuel cell in which electrolyte is circulated and supplied in parallel to each unit cell that makes up the fuel cell body, leakage current is generated through the common electrolyte supply line that communicates between each unit cell. Therefore, the reaction gas is always consumed little by little even during no-load operation. For this reason, when the reactant gas is supplied from gas cylinders 2 and 3 as the reactant gas supply source as shown in Figure 4, if the non-power generation state without load operation continues for a long period of time, the amount of gas in the cylinder will gradually increase. For this reason, load operation is not carried out (but sometimes cumbersome maintenance management is required, such as replacing the gas cylinder with a new one).
If a 7rrl cylinder is used for one fuel cell per year, it is necessary to replace the cylinder approximately once every six months even when power is not being generated. (2) In addition to the gas consumption due to the leakage current mentioned above, there is an unavoidable gas leakage from the structural aspects of the reactant gas line in the fuel cell main body, which causes the reactant gas in the gas cylinder to be consumed. The gas cylinder will need to be replaced. As described above, if the reaction gas supply source of the conventional power generation equipment is used as it is, maintenance and management of the reaction gas supply source is troublesome, and there is a desire for an improvement in this point.

[Purpose of the invention]

The present invention has been made in view of the above points, and an object of the present invention is to provide a reactant gas supply device for fuel cell power generation equipment that eliminates the drawbacks of conventional devices and has excellent maintainability.

[Key points of the invention]

In order to achieve the above object, the present invention connects an auxiliary reactive gas generator that produces fuel and oxidizer separately from the reactive gas supply source to the reactive gas supply line through a branch gas supply line, and provides power to the load. During load operation, the reactant gas is supplied from the reactant gas supply source to the fuel cell main body, and when power generation is not being performed, such as when power generation is stopped, the reactant gas consumed by the fuel cell main body is replenished from the reactant gas generator. This suppresses unnecessary gas consumption on the side of the reactant gas supply source and simplifies maintenance and management in terms of reactant gas replenishment. In this case, a suitable reaction gas generating device is a water electrolysis device that generates hydrogen as a fuel and oxygen as an oxidizing agent by electrolysis using an electrolyte aqueous solution as a raw material.

[Embodiments of the invention]

FIG. 1 is a system diagram of a reaction gas supply apparatus according to the present invention, and the same members as in FIG. 4 are given the same reference numerals. That is, a hydrogen cylinder 2 and an oxygen cylinder 3 as reaction gas supply sources are connected to the fuel cell main body 1 via reaction gas supply lines 4.5 for fuel and oxidizer, and the gas is supplied by a first pressure regulating valve 6. The pressure is regulated to about 500a+s+Ag and the reactant gas is supplied to the fuel cell main body l. On the other hand, within the system of the power generation equipment, the above-mentioned hydrogen and oxygen cylinders 2.3 are used as the main reactant gas supply sources, and a branch line 8, which is drawn out from the reactant gas supply line 4.5 separately from this reactant gas supply source, is provided. 9 is connected to a small capacity auxiliary reaction gas generator indicated by 10. As this reaction gas generation device, for example, a commercially available hydrogen-oxygen generator using a commercial power source is employed. In addition, pressure is applied to the branch line 8.9 at the first line.
The second pressure regulating valve 11 is regulated to a pressure of about 600 mmAg, which is higher than that of the pressure regulating valve 11. A relief valve 12 is also provided to release the reaction gas to the outside of the system when the gas pressure within the system exceeds a set value. Note that 13 is a pressure switch that detects a decrease in the system gas pressure on the fuel cell main body side and issues a signal to operate the reaction gas generator 10, and its operating pressure is 550 mm.
It is set to about Ag. Next, the reaction gas supply operation with the above configuration will be explained. First, the fuel cell main body 1 is preset with 60
The reaction gas is sealed at a pressure of about 0s+mAg,
In this state, power generation is on standby. In this power generation standby state, as mentioned above, due to the occurrence of leakage current in the fuel cell main body or the consumption of reactant gas due to a slight leakage of the reactant gas, the gas pressure within the system of the fuel cell main body reaches 550 mm, which is the lower limit of the cell sealing pressure.
When the pressure decreases to Ag, the pressure switch 13 is activated and sends a signal to the reaction gas generator 10, whereby the reaction gases of hydrogen and oxygen generated in the reaction gas generator 10 are sent through the branch lines 8 and 9 to the fuel cell main body 1. supply to. In this case, even when the pressure of either the hydrogen system or the oxygen system decreases, the reaction gas generator 10 operates, and excess gas is released to the outside of the system through the relief valve 12. On the other hand, in this state, the gas pressure in the system is
Since the pressure is higher than the set pressure of the gas cylinder 2.3, the reaction gas will not flow out from the gas cylinder 2.3. In this way, in the non-power generation state where power generation is stopped, the reactant gas filled in the reactant gas supply sources 2 and 3 is not consumed, and in this state, the fuel cell main body due to leakage current or reactant gas leakage. The small amount of consumption of the reaction gas in 1 is the reaction gas generation value! The fuel is supplied to the fuel cell main body 1 from 10. Therefore, the inside of the fuel cell main body 1 is always maintained at a predetermined gas pressure. On the other hand, when the fuel cell main body 1 enters a load operation state in which power is supplied to the load from the above-mentioned no-load state, steady power generation can be instantaneously started because the fuel cell main body 1 is maintained at a predetermined gas pressure at this point. Also, in this load operation state, the fuel cell main body 1 consumes a large amount of reaction gas.
Gas supply of 10h1^ is not enough to cope with the load operation, and therefore the gas pressure in the system tries to drop quickly, but if the gas pressure falls below 500+ms+Ag during this process, the first pressure regulating valve 6 Through this, the reaction gas is automatically supplied from the hydrogen and oxygen cylinders 2.3, and thereby the reaction gas is supplied in accordance with the load operation. After that, when power generation is stopped again, the above-mentioned no-load state is returned, and the small amount of reaction gas consumed in the fuel cell main body 1 is covered by gas replenishment from the reaction gas generator 10. Next, a specific configuration example of an embodiment applied in place of the above-mentioned reaction gas generator 10 and second pressure regulating valve 11 will be described in the second section.
The reactive gas generator 30 shown in FIG. 2, which is equipped with an automatic pressure regulating valve function, includes an electrolytic cell 14 filled with an aqueous electrolyte solution, and a lower open end of the electrolytic cell 14 that is immersed in the aqueous solution in the electrolytic cell 14. Hydrogen generation tube 15 and oxygen generation tube 16 installed vertically, and electrodes 17 and 18 for electrolysis on the cathode and anode sides inserted into the lower portions of the generation tubes 15 and 16.
and a DC power source 19 for electrolysis connected between the electrodes. Note that the hydrogen generation tube 15 and the oxygen generation tube 16 are connected and connected to the reaction gas supply line 4.5 shown in FIG. 1, respectively. With this configuration, by passing current from the power supply 19 between the electrodes 17 and 18, hydrogen gas is generated from the electrode 17 side and oxygen is generated from the electrode 18 side, and is supplied to the fuel cell main body l through the reaction gas supply line. be done. In addition, in this case, by appropriately setting the liquid level of the electrolytic cell 14 and the installation level of the electrodes 17 and 18 in accordance with the set gas pressure in the system, the replenishment of the reaction gas progresses and the fuel cell main body side At the point where the gas pressure in the system has increased to a predetermined pressure, the hydrogen and oxygen generation pipes 15.16
The liquid level inside the tube is pushed down by the gas pressure inside the tube, and the electrode 17
．． 18 comes to be exposed above the liquid surface, and self-control is performed so that current supply is automatically stopped and gas generation is also stopped. Furthermore, if the gas pressure in the system decreases from a predetermined value due to gas consumption caused by leakage current, gas leakage, etc. on the fuel cell main body side from this state, then the electrode 17
．． 18 is immersed below the liquid surface, and the generation and replenishment of reaction gas is automatically restarted. In the example shown in Fig. 2, if an unbalanced state occurs in which either the fuel or the oxidizer gas is consumed more than the other side, which electrode is in the solution. Even if the electrode is immersed in water, the electrode on the other side is exposed above the liquid surface, so it will not be energized and there is a risk that it will not be possible to immediately replenish the gas. In other words, in the reactive gas generation device shown in FIG. The auxiliary electrode 20 is the changeover switch 2
1 to selectively switch to either the positive or negative terminal side of the power source 19. With such a configuration, if a large amount of hydrogen is consumed among hydrogen and oxygen, for example, by connecting the switch 21 described above in parallel with the oxygen side electrode, the gas pressure on the hydrogen side can be adjusted as shown in the figure. Even if an unbalanced liquid level condition occurs in which only the electrode 17 is submerged below the liquid surface due to a drop in the liquid, the current is maintained between the electrode 17 and the auxiliary electrode 20 that is constantly immersed in the solution. This makes it possible to continue disassembly, allowing only the gas on the consumable side to be supplied to the fuel cell main body through piping. Note that the oxygen generated on the auxiliary electrode 20 side rises in the solution as it is and is dissipated out of the tank. On the other hand, if consumption on the oxygen side is large, the auxiliary electrode 20 described above may be connected in parallel to the electrode on the hydrogen side. Effects of the Invention As described above, according to the present invention, a small-capacity auxiliary reaction gas generator that produces fuel and an oxidizer separately from the reaction gas supply source is installed in the system to supply the reaction gas. During load operation, the reactant gas is supplied from the above-mentioned reactant gas supply source to the fuel cell main body, and when power generation is stopped and no power is generated, the reactant gas consumed by the fuel cell main body is By configuring the fuel cell to be refilled from the reactive gas generator, the small amount of reactive gas consumed in the fuel cell body during non-power generation is automatically replenished from the auxiliary reactive gas generator, eliminating the need for reactive gas. This makes it possible to simplify the maintenance and management of the reactant gas supply source.

[Brief explanation of the drawing]

FIG. 1 is a reaction gas supply system diagram of a fuel cell power generation facility according to an embodiment of the present invention, FIGS. 2 and 3. 1: Fuel cell main body, 2: Hydrogen cylinder as a reaction gas supply source, 3: Oxygen cylinder , 4, 5; reaction gas supply line, 10: reaction gas generator, 14: electrolytic cell, 15.16: gas generation tube, 1
7.18: electrode for electrolysis, 19: power supply for electrolysis, 20: auxiliary electrode, 30: reaction gas generator with automatic pressure adjustment function. De J Shichiri puji Yamaguchi breath easy 2vA Figure 3

Claims (1)

[Claims] 1) A fuel that includes a fuel cell main body and a reactive gas supply source, and generates power by supplying fuel and a reactive gas of an oxidizer to the fuel cell main body through a reactive gas supply line from the reactive gas supply source. In battery power generation equipment, a small-capacity auxiliary reactive gas generator that produces fuel and oxidizing agent separately from the reactive gas supply source is connected to the reactive gas supply line through a branch gas supply line, and is connected to the reactive gas supply line in case of emergency such as power generation stoppage. A reactant gas supply device for fuel cell power generation equipment, characterized in that during power generation, the reactant gas consumed on the fuel cell main body side is replenished from the reactant gas generator. 2) In the reaction gas supply device according to claim 1, the reaction gas supply line is provided with a pressure regulating valve, and the branch gas supply line is provided with a second pressure regulating valve, and the second pressure regulating valve A reaction gas supply device for fuel cell power generation equipment, characterized in that the set pressure of the first pressure regulating valve is set higher than the set pressure of the first pressure regulating valve, and the lower limit of the gas filling pressure of the battery body during non-power generation is set. 3) In the reactant gas supply device according to claim 1, an on-off valve is interposed in the reactant gas supply line, and the reactant gas generator is connected to water that electrolyzes an aqueous electrolyte solution to generate hydrogen and oxygen. A reactant gas supply device for fuel cell power generation equipment, characterized in that it is configured as an electrolysis device. 4) In the reactive gas supply device according to claim 3, the reactive gas generating device comprises an electrolytic tank filled with an aqueous electrolyte solution, and a hydrogen generating tube disposed with its lower open end immersed in the electrolytic tank. and an oxygen generating tube, an electrode for electrolysis installed at the lower part of each generating tube, and a power source for electrolysis connected between the electrodes, and the hydrogen generating tube and the oxygen generating tube correspond to each other. A reaction gas supply device for fuel cell power generation equipment, characterized in that it is connected to a gas supply line. 5) In the reaction gas supply device according to claim 4, the hydrogen and oxygen generation pipes in the electrolytic cell are selectively connected in parallel to either the hydrogen side or the oxygen side electrolysis electrodes on the outside. A reactant gas supply device for fuel cell power generation equipment, characterized in that an auxiliary electrode is provided.