JP3680671B2 - Power generator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention uses an off-gas discharged from the anode of a polymer electrolyte fuel cell or an incomplete product gas outside a desired composition discharged from a hydrogen generator as a fuel gas for heating the hydrogen generator. The present invention relates to a power generator using a polymer electrolyte fuel cell.
[0002]
[Prior art]
Hereinafter, a power generator using a conventional polymer electrolyte fuel cell will be described with reference to FIG. Reference numeral 1 denotes a polymer electrolyte fuel cell unit, in which an air electrode 2 and a fuel electrode 3 are arranged with a polymer electrolyte membrane 9 (for example, manufactured by DuPont; Nafion 117) interposed therebetween. The upstream side of the air electrode 2 communicates with a fan 4 that supplies air, and the upstream side of the fuel electrode 3 communicates with a hydrogen generator 6 via a switching valve 5. A combustion unit 7 is provided adjacent to the hydrogen generator 6, and the hydrogen generator 6 is heated by heat generated in the combustion unit 7. A combustion amount control valve 8 is provided upstream of the combustion unit 7. When a raw material fuel such as natural gas or methanol and raw water necessary for the steam reforming reaction are supplied to the hydrogen generator 6 and fuel is supplied to the combustion unit 7 via the combustion amount control valve 8, the combustion unit The hydrogen generator 6 is heated to a predetermined temperature by the combustion heat generated at 7. While the hydrogen generator 6 is not at a predetermined temperature, the product gas contains a lot of poisoning components such as CO, resulting in an incomplete product gas outside the desired composition. This incomplete product gas was not supplied to the fuel electrode 3 but was discharged to the outside through the switching valve 5.
[0003]
Further, when the hydrogen generator 6 is heated to a predetermined temperature and a product gas having a desired composition is obtained, the switching valve 5 is operated to supply the product gas to the fuel electrode 3, and the polymer electrolyte fuel cell 1 generates power. Be started. The generated gas supplied to the fuel electrode 3 is discharged from the fuel electrode 3 to the outside as an off gas containing hydrogen after most of the hydrogen is consumed by power generation.
[0004]
As described above, in the power generation apparatus using the conventional polymer electrolyte fuel cell, the generated gas cannot be used as the fuel for the fuel electrode when the hydrogen generator 6 is not at a predetermined temperature at the time of startup or the like. This gas is discharged to the outside, and there is a problem that it may be ignited by some ignition source.
[0005]
Furthermore, since the off gas discharged from the fuel electrode 3 contains hydrogen that has not been consumed by power generation, if it is discharged as it is, there is a possibility that it may be ignited by any ignition source, or it may be generated without ignition. Since a part of the generated hydrogen is discharged to the outside, there is a problem that the operation efficiency of the power generation device is lowered.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to solve the above-described problems of the prior art, and to provide a power generator having a high operating efficiency without the possibility of improper ignition, in which a gas containing hydrogen is not discharged to the outside as it is. For the purpose.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention according to claim 1 is directed to a hydrogen generator that generates a hydrogen-rich gas from a hydrocarbon-based raw material fuel and water, and a generated gas and an oxidation obtained by the hydrogen generator. A polymer electrolyte fuel cell that generates electric power using an agent gas; a combustion unit that heats the hydrogen generator; a combustion amount control valve that controls a supply amount of fuel supplied to the combustion unit; and the combustion A communication part connecting the quantity control valve and the combustion part, at least one of an off-gas exhausted from the fuel electrode of the polymer electrolyte fuel cell and an incomplete product gas produced by the hydrogen generator A power generation device is provided that includes a merging portion that merges with the communication portion, and a pressure guiding pipe that guides pressure between the merging portion and the combustion amount control valve to the combustion amount control valve.
[0008]
Moreover, in order to solve the said subject, this invention of Claim 2 comprised further the electric power generating apparatus of Claim 1 which provided the on-off valve between the junction part and the pressure guiding tube.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
According to the first aspect of the present invention, at least one of the off-gas discharged from the fuel electrode and the incompletely generated gas generated by the hydrogen generator (hereinafter referred to as off-gas, etc.) is merged in the communicating portion. The fuel is mixed into the fuel from the section and supplied to the combustion section. At that time, the gas flow downstream of the merging portion increases due to the mixing of off-gas, etc., so the flow resistance increases, the pressure downstream of the combustion amount control valve increases, and the opening of the combustion amount control valve decreases. However, the amount of fuel gas passing therethrough is reduced, but the pressure between the junction and the combustion amount control valve is guided to the combustion amount control valve by the pressure guiding pipe. The fuel gas amount can be kept constant by acting to increase the degree.
[0010]
Conversely, when the amount of off-gas etc. decreases, the pressure of the combustion amount control unit and the merging unit decreases, so the opening of the combustion amount control valve increases and the amount of fuel gas passing through the combustion amount control valve increases. However, since the pressure between the combustion amount control valve and the merging section is guided to the combustion amount control valve by the pressure guiding pipe, the pressure drop acts to reduce the opening of the combustion amount control valve, and the fuel The gas amount can be kept constant.
[0011]
In other words, even if the amount of off-gas mixed in the junction increases or decreases, the amount of fuel gas can be maintained at a predetermined amount, and the combustion state in the combustion unit can be stably maintained. It can be supplied to the combustion section without being discharged.
[0012]
Since off gas or the like is not discharged to the outside, it is possible to eliminate the possibility of combustible gas containing hydrogen being ignited, and to improve the operating efficiency of a power generator using a fuel cell.
[0013]
According to the second aspect of the present invention, when the operation is stopped, the on-off valve is closed, and the junction, the pressure guiding pipe, and the combustion amount control valve are shut off.
[0014]
When this on-off valve is not provided, the off gas and the like contain a lot of water vapor, so when the operation is stopped and the supply of the fuel gas is stopped, the off gas or the like in the path diffuses to the pressure guiding pipe and the combustion amount control valve, As the temperature drops, water vapor contained in the off-gas and the like is condensed. Condensed water accumulates in the pressure guiding pipe and the combustion amount control valve, so that a pulsation occurs in the fuel flow when the operation is resumed, resulting in a new problem that the combustion state in the combustion section becomes extremely unstable.
[0015]
However, when the operation is stopped by the on-off valve, the junction, the pressure guiding pipe and the combustion amount control valve are shut off, so it is possible to prevent the formation of condensed water by eliminating the diffusion of off-gas etc. to the pressure guiding tube and the combustion amount control valve. The combustion state of the combustion section can be stabilized even if the operation is repeatedly stopped and restarted.
[0016]
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
(Embodiment 1)
FIG. 1 is a configuration diagram of a power generator using a polymer electrolyte fuel cell according to an embodiment of the present invention. In the figure, components having the same functions as those of the power generation apparatus using the conventional polymer electrolyte fuel cell shown in FIG. 3 are given the same reference numerals, and details of those functions are shown in FIG. The same shall apply. A combustion amount control valve 8 is provided upstream of the combustion unit 7. The combustion amount control valve 8 and the combustion unit 7 are connected by a communication unit 10. The communicating part 10 is provided with a merging part 11, and the merging part 11 is mixed with off-gas exhausted from the fuel electrode 3 or incompletely produced gas (off-gas etc.) from the hydrogen generator 6. . A pressure guiding tube 12 is provided on the upstream side of the merging portion 11. The control unit 13 and the combustion amount control valve 8 are connected by a signal line 14. A reverse funnel-shaped valve body 15 is held inside the combustion amount control valve 8 by a diaphragm 16, and a gap 18 formed by the opening 17 and the valve body 15 serves as a fuel gas flow path. A magnet 19 is fixed to the upper part of the valve body 15, and an iron core 20 and a coil 21 are provided above the magnet 19 with a space therebetween. The upper space of the diaphragm 16 is communicated with the downstream side of the combustion amount control valve 8 by the pressure guiding pipe 12.
[0018]
Next, the operation and action will be described. A control current is supplied from the control unit 13 to the coil 21 via the signal line 14, a magnetic force repelling the magnet 19 is generated in the iron core 20, and the magnet 19 is pushed downward by a predetermined force, and the valve body 15 and the opening A gap 18 that defines the flow rate of the fuel gas is formed between the first and second gas sources. The fuel gas flows in from the fuel gas inlet of the combustion amount control valve 8, flows through the gap 18, and is supplied to the combustion unit 7 through the joining part 11 from the communication part 10 connected to the fuel gas outlet. Off-gas and the like are mixed into the fuel gas from the merging portion 11 provided in the communication portion 10 and supplied to the combustion portion 6. Since the gas flow rate downstream of the merging portion 11 increases due to the mixing of off gas or the like, the flow path resistance increases, the pressure on the downstream side of the combustion amount control valve 8 rises, the valve body 15 is pushed upward, and the gap 18 is formed. Since it decreases, the amount of combustion gas decreases. However, since the pressure increase on the downstream side of the combustion amount control valve 8 is transmitted to the upper space of the diaphragm 16 by the pressure guiding pipe 12, the diaphragm 16 moves downward and the strain valve body 15 moves downward, so that the gap 18 becomes wide. The combustion gas amount can be prevented from decreasing, and the fuel gas amount can be kept constant.
[0019]
Conversely, when the amount of off-gas etc. decreases, the pressure on the downstream side of the combustion amount control unit 8 decreases, but the pressure decrease on the downstream side of the combustion amount control valve 8 is transmitted to the upper space of the diaphragm 16 by the pressure guiding pipe 12. In addition, since the gap 18 becomes smaller, the fuel gas amount can be kept constant. That is, even if the amount of gas mixed into the merging portion 11 increases or decreases, the amount of fuel gas can be maintained at a predetermined amount, and the combustion state in the combustion portion 7 can be stably maintained. It can be supplied to the combustion section 7 without being discharged. Since off-gas or the like is not discharged to the outside, the possibility of combustible gas containing hydrogen being ignited can be eliminated, and the operating efficiency of the power generation apparatus can be improved.
[0020]
(Embodiment 2)
FIG. 2 is a configuration diagram of a power generation apparatus using a polymer electrolyte fuel cell according to another embodiment of the present invention. The difference from the first embodiment is that an on-off valve 30 is provided between the merging portion 11 and the pressure guiding tube 12. Note that components having the same reference numerals as those in (Embodiment 1) have the same configuration and description thereof is omitted.
[0021]
Next, the operation and action will be described. When the operation is stopped, the on-off valve 30 is closed, and the merging portion 11, the pressure guiding pipe 12 and the combustion amount control valve 8 are shut off. Since off gas and the like contain a lot of water vapor, when the fuel gas supply is stopped when the operation is normally stopped or the operation is stopped for some reason, the off gas or the like is controlled by the pressure guiding pipe 12 and the combustion amount control. The water vapor diffuses into the diaphragm 16 inside the valve 8 and the water vapor contained therein is condensed as the temperature decreases. Since condensed water accumulates in the pressure guiding tube 12 and the diaphragm 16, etc., even if the control current supplied to the coil 21 is constant, the gap 18 does not become constant and fluctuates. Therefore, the combustion state in the combustion section 7 becomes extremely unstable. However, by closing the on-off valve 30, the merging portion 11, the pressure guiding pipe 12, and the combustion amount control valve 8 can be shut off when the operation is stopped, so that diffusion of off-gas and the like to the pressure guiding tube 12 and the combustion amount control valve 8 is prevented. Since it can be eliminated and the generation of condensed water can be prevented, the combustion state of the combustion section 7 can be stabilized even if the operation is stopped and restarted repeatedly.
[0022]
【The invention's effect】
As described above, according to the present invention, the pressure guiding pipe that guides the pressure change on the downstream side of the combustion amount control valve to the combustion amount control valve is provided, so that even if the amount of gas mixed into the junction increases or decreases. The amount of fuel gas can be maintained at a predetermined amount, the combustion state in the combustion section can be maintained stably, and off-gas from the fuel electrode or incompletely generated product gas (off-gas etc.) from the hydrogen generator It can be supplied to the combustion section without being discharged. Since off-gas or the like is not discharged to the outside, the possibility of combustible gas containing hydrogen being ignited can be eliminated, and the operating efficiency of the power generation apparatus can be improved.
[0023]
In addition, since the on-off valve is provided between the junction and the pressure guiding pipe, the on-off valve can be closed when the operation is stopped, and the junction, the pressure guiding pipe, and the combustion amount control valve can be shut off. It is possible to eliminate the diffusion of off-gas, etc. to the combustion amount control valve, and it is possible to prevent the formation of dew condensation water due to the water vapor contained in these gases. Can be stabilized.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a power generation device using a polymer electrolyte fuel cell according to an embodiment of the present invention. FIG. 2 is a power generation using a polymer electrolyte fuel cell according to a different embodiment of the present invention. Configuration diagram of the device [Fig. 3] Configuration diagram of a power generation device using a conventional polymer electrolyte fuel cell [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Polymer electrolyte type fuel cell 2 Air electrode 3 Fuel electrode 4 Fan 5 Switching valve 6 Hydrogen generator 7 Combustion part 8 Combustion amount control valve 9 Polymer electrolyte membrane 10 Communication part 11 Merging part 12 Pressure guiding pipe 15 Valve body 16 Diaphragm 17 Opening 18 Clearance 19 Magnet 20 Iron core 21 Coil

Claims (2)

A hydrogen generator that generates a hydrogen-rich gas from a hydrocarbon-based raw material fuel and water, and a polymer electrolyte fuel cell that generates power using the generated gas and the oxidant gas obtained from the hydrogen generator; A combustion unit that heats the hydrogen generator, a combustion amount control valve that controls a supply amount of fuel supplied to the combustion unit, a communication unit that connects the combustion amount control valve and the combustion unit, and A merging portion for merging at least one of an off-gas discharged from a fuel electrode of a polymer electrolyte fuel cell and an incompletely generated gas generated in the hydrogen generator into the communicating portion; the merging portion and the combustion And a pressure guiding pipe for guiding the pressure between the amount control valve to the combustion amount control valve. The power generator according to claim 1, further comprising an on-off valve between the junction and the pressure guiding tube.

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