JPH05294601A - Methanol-switching fuel cell power generator - Google Patents

Abstract

PURPOSE:To provide a methanol-switching fuel cell power generator capable of smoothly switching the fuel even from the normal liquid state of methanol. CONSTITUTION:A methanol evaporator 30 covered its circumference with a heat-insulation material contains a methanol sprayer 33 at the upper part and a heat-exchanger 34 to heat the mist generated by the methanol sprayer 33 in the middle part of the evaporator. A heat-exchanger 19 is permanently connected to the outlet of a cooler 18 of the main body 12 of the fuel cell. Hot water branched from the outlet of the heat-exchanger 19 is supplied to the heat-exchanger 34 through a hot water line 35 to heat the exchanger. The methanol sprayer 33 is supplied with liquid methanol 23 pumped up from a methanol storage tank 31 with a methanol supplying pump 36 in the case of switching the fuel. The methanol vapor generated in the methanol evaporator 30 is supplied to an ejector 7 via a methanol vapor supply line 39. A reformer 32 is provided with an exclusive burner for methanol liquid and the methanol liquid 23 branched from the methanol evaporator 30 is ejected in the case of switching the fuel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a methanol switching type fuel cell power generator capable of supplying stable electric power by automatically switching to a methanol liquid as a reserve fuel even when the city gas which is constantly introduced is shut off. It is about.

[0002]

2. Description of the Related Art Gas fossil fuels or methanol fuels containing methane as a main component, such as natural gas and city gas, are widely used in fuel cell power generators. These fuels are reformed by a reformer to supply hydrogen to the fuel cell body. Methanol fuel can be stored in a large amount when stored as a liquid, and is easy to handle. Therefore, always introduce natural gas or city gas, and use methanol as a backup fuel when the supply of these is interrupted for some reason. The method is considered optimal.

FIG. 2 shows an example of a conventional methanol switching system. That is, as shown in the figure, in the conventional fuel cell power generator, the fuel supply valve 1 is operated during normal operation.
Open to introduce the city gas through the city gas supply lines 2a and 2b, join the recirculation line 5 branched from the reformed gas line 4 on the outlet side of the low temperature shift transformer 3, and connect the hydrodesulfurization device 6 After that, it is supplied to the ejector 7.

On the other hand, the ejector 7 is supplied with water vapor from the separator 8 through the water vapor line 9. As a result, the water vapor and the city gas are uniformly mixed in the ejector 7 at an appropriate ratio and supplied to the reformer 10. After being heated in the reformer 10 and undergoing a reforming reaction, it is supplied to the low temperature shift transformer 3.

In the reformer 10, due to the internal catalyst layer, C
A chemical reaction of H ₄ + H ₂ O → 3H ₂ + CO is performed, and CO + H ₂ O is generated by the internal catalyst layer in the low temperature shift transformer 3.
→ H ₂ + chemical reaction CO ₂ is performed battery supply line 11
Is supplied to the hydrogen electrode 13 of the fuel cell main body 12 through the hydrogen, and the remaining hydrogen is used through the burner line 14 for the remaining hydrogen.
Supplied to 10 burners. This burner has an air compressor
Since air is supplied from 15, it burns and heats the reformer 10. Further, air is sent from the air compressor 15 to the oxygen electrode 16 of the fuel cell body 12. On the other hand, the cooling water of the fuel cell main body 12 is supplied from the separator 8 to the cooler 18 via the pump 17, returns to the separator 8 via the heat exchangers 19 and 20, and is circulated.

The flow during normal operation is as described above,
When the pressure in the city gas line 2a drops below a predetermined value, a pressure detector provided in this city gas supply line 2a
This is detected by 21, and the methanol liquid 23 stored in the methanol evaporator 22 is heated and vaporized by the heater 24 in advance and the methanol vapor is introduced into the city gas supply line 2b by opening the vapor supply valve 25. At this time, the fuel supply valve 1 on the city gas supply line 2a side is closed simultaneously with the opening of the steam supply valve 25. Incidentally, methanol is a liquid at room temperature, even if the heater 24 is turned on after the switching command is issued, it takes several tens of minutes to vaporize, during which hydrogen is not introduced into the fuel cell body 12, The voltage drops and shuts down. Reference numeral 26 indicates a steam safety valve, and reference numeral 27 indicates reformer combustion exhaust gas.

[0007]

However, it is not only a waste of electric power that the heating of the heater of the methanol evaporator is always used during normal operation, but the methanol liquid is always in the vapor state. It is not preferable for safety reasons. Further, if the methanol liquid is kept in a vapor state for a long time, formic acid (HCOOH) is generated, which may corrode the inner surface of the methanol evaporator. Therefore, an object of the present invention is to provide a methanol switching fuel cell power generation device that can smoothly switch fuel even when methanol is in a normal liquid state.

[0008]

In order to achieve the above-mentioned object, the present invention constantly introduces city gas and reforms it with a reformer, and supplies it as hydrogen-rich gas to the fuel cell body to generate electricity. In a methanol-switching fuel cell power generator that is designed to supply methanol to a reformer after vaporizing the methanol solution when the gas is shut off, the reformer is equipped with a burner that ejects the methanol solution. Is provided with a jetting part for generating a mist of methanol liquid and a heating part for supplying the hot water discharged from the cooler of the fuel cell main body to vaporize the mist.

[0009]

In the present invention, the vaporization process of the methanol liquid starts only when the methanol switching command is issued. At this time, the vaporized amount is only the amount necessary for continuous operation. The amount is extremely small compared with the case where all the methanol solution in the inside is vaporized. In addition, since the mist of methanol liquid is heated to increase the surface area and then heated, it can be easily vaporized, so that all the necessary amount is vaporized in the short time when the mist of methanol passes, and then is ejected to the ejector inlet side. Supplied.

Further, in the fuel cell main body, if hydrogen gas is not introduced for several minutes, the voltage drops and shuts down. However, the methanol gas switched from the city gas is reformed to produce hydrogen gas. Since it is generated, it can be operated without reaching the above-mentioned shut down. However, city gas shutoff and methanol injection / vaporization /
There may be a temporary shortage of hydrogen gas in the fuel cell body during the reforming process, but the voltage does not drop suddenly due to the buffer effect of the fuel cell until sufficient hydrogen gas is supplied again. You can answer.

On the other hand, the combustion gas of the burner of the reformer is supplied with the remaining gas which has consumed hydrogen in the fuel cell main body, so that the delay is further increased and the burner of the reformer may misfire. However, by switching the fuel from city gas to methanol liquid and simultaneously ejecting the methanol liquid to the burner side of the reformer, this burns instead of the reformed gas of city gas in the burner chamber of the reformer. As a result, the burner can be prevented from misfiring, and the operation can be continued without reaching the shut down.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. The same parts as those in the conventional configuration described above are designated by the same reference numerals, and duplicate description will be omitted. In FIG. 1, 30 is a methanol evaporator, 31 is a methanol storage tank, and 32 is a reformer.

The above-mentioned methanol evaporator 30 is covered with a heat insulating material around the inside thereof, and is equipped with a methanol atomizer 33 in the upper part and a heat exchanger 34 for heating the mist generated by the methanol atomizer 33 in the middle part. In the heat exchanger 34, hot water at the outlet of the heat exchanger 19 that is always connected to the outlet side of the cooler 18 of the fuel cell main body 12 is branched and supplied through the hot water line 35 to be heated, and then to the methanol sprayer 33. Supplies the methanol liquid 23 pumped from the methanol storage tank 31 via the fuel supply methanol supply pump 36 by opening the methanol supply valve 37.

In the methanol evaporator 30, the methanol liquid 23 that has not become methanol vapor is stored in the lower part,
It is discharged to the methanol storage tank 31 via the discharge valve 38, and the methanol vapor is supplied to the ejector 7 via the methanol vapor supply line 39.

On the other hand, the reformer 32 is the conventional reformer described above.
10, a methanol liquid dedicated burner is provided, and the methanol liquid 23 branched from the above methanol evaporator 30 is supplied via the methanol burner supply valve 40 at the time of fuel switching,
It is designed to spray from a burner. Here, the methanol burner supply valve 40 is configured to be openable / closable by an external electric signal or the like.

Next, the operation of the embodiment configured as described above will be described. Normal city gas operation is similar to the above-mentioned conventional operation, but in this case also, the methanol evaporator 30
First, hot water at the outlet of the heat exchanger 19 of the fuel cell main body 12 is branched and supplied to the heat exchanger 34 for heating.

Now, when an abnormality occurs in the city gas supply line 2a and the pressure drops, and the pressure detector 21 detects this, the methanol supply pump 36 is immediately activated to drive the methanol liquid.
23 is fed to the methanol evaporator 30. Methanol sprayer
The methanol vapor ejected at 33, heated by the heat exchanger 34 and evaporated is supplied to the ejector 7 via the methanol vapor supply line 39. At the same time, the methanol liquid 23 is also supplied to the reformer 32, and the methanol liquid 23 is sprayed from the burner to prevent the burner of the reformer 32 from misfiring. However, this period is limited to a certain period by a timer or the like.

Therefore, according to the embodiment configured as described above, the methanol liquid 23 evaporates in a very short time as compared with the conventional apparatus described above, and the reformer 32 reforms into hydrogen. Since the hydrogen gas is supplied to the hydrogen electrode 13 of the fuel cell main body 12, the output is recovered again tens of seconds after the supply of city gas is stopped.

Further, although the methanol evaporator 30 is heated by hot water during the normal operation, the methanol liquid 23 is not jetted out, so that there is almost no loss of heat quantity. Although the amount of heat is lost by the amount of heat radiated from the surroundings of the methanol evaporator 30, the amount is very small because the methanol evaporator 30 is kept warm.

Further, when switching to methanol, the reformed gas after switching is protected from the misfire by directly spraying the methanol solution to the burner of the reformer 32 for several tens of seconds to several minutes to prevent the burner from misfiring. Combustion is continued until the fuel cell body 12 comes around and fuel is smoothly switched on the burner side.

In the above-described embodiment, the methanol supply valve 37 is provided on the front side where the methanol liquid 23 is branched into the methanol evaporator 30 and the reformer 32, but the line toward the methanol evaporator 30 after branching is provided. It may be provided in the middle.

[0022]

As described above, according to the present invention, the reformer is provided with the burner for ejecting the methanol liquid, and the methanol evaporator is provided with the ejection portion for generating the mist of the methanol liquid and the constant fuel cell main body. Since a heating unit that supplies hot water from the cooler to vaporize the mist is provided, when the city gas supply is cut off and switched to methanol liquid, methanol vapor is quickly generated and modified. The quality of the fuel cell can be supplied to the fuel cell main body, and the operation can be continued without reaching the shut down. In addition, since the methanol liquid is not jetted by the methanol evaporator in the normal operation, the heat loss is small and the heating source is hot water, so that the safety is improved without overheating. Furthermore, when switching from city gas to methanol solution, the methanol solution is temporarily ejected directly to the reformer until the reformed gas is supplied from the fuel cell body to the reformer. It is possible to prevent misfire of the burner in the furnace and continue combustion. As described above, it is possible to provide a methanol switching fuel cell power generation device that can smoothly switch to a methanol liquid and continue operation even when the supply of city gas is stopped.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional methanol switching fuel cell power generator.

[Explanation of symbols]

2a, 2b ... City gas supply line, 7 ... Ejector, 8
… Separator, 10, 32… Reformer, 12… Fuel cell body, 13… Hydrogen electrode, 15… Air compressor, 16… Oxygen electrode, 18… Cooler, 19,
20, 34 ... Heat exchanger, 21 ... Pressure detector, 22, 30 ... Methanol evaporator, 23 ... Methanol liquid, 31 ... Methanol storage tank, 35 ... Hot water line, 36 ... Methanol supply pump, 39 ...
Methanol vapor supply line, 40 ... Methanol burner supply valve.

Claims (1)

[Claims] 1. A city gas is constantly introduced and reformed by a reformer, and hydrogen-rich gas is supplied to the fuel cell main body to generate electricity. When the city gas is shut off, a methanol liquid is vaporized by a methanol evaporator. In the methanol switching fuel cell power generator configured to be supplied to the reformer later, a burner for ejecting the methanol liquid is provided in the reformer, and a mist of the methanol liquid is generated in the methanol evaporator. A methanol switching fuel cell power generator comprising: a jetting section and a heating section supplied with hot water discharged from a cooler of the fuel cell body to vaporize the mist.