JP3945978B2 - Fuel cell power supply - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a small fuel cell power supply device developed especially for home use.
[0002]
[Prior art]
There is a power supply device mainly composed of fuel cells, and those that are formed for home use conventionally have a fuel cell power supply device A installed outdoors as shown in FIG. The electric power (direct current) is converted into alternating current by the DC / AC inverter B and supplied to, for example, an indoor personal computer D, a lighting fixture E, a refrigerator F, an air conditioner G, and a television H via a switchboard C. In this case, since the output of the fuel cell power supply device A is about 1 kW, it is difficult to supply power to all indoor electric devices, and the shortage is supplied from a commercial power supply.
[0003]
Further, since heat is generated in the process of power generation in the fuel cell power supply device A, hot water is generated from city water using this heat, and this hot water is stored in the hot water storage tank I and supplied to the bath J, kitchen K, etc. Is done. The city water is also supplied to the fuel cell in the fuel cell power supply device A to cool it.
[0004]
In the fuel cell power supply device A, a reformer (desulfurizer, reformer, CO converter, CO remover) for reforming a fuel gas such as city gas into a hydrogen rich gas, and the reformer are supplied. A fuel cell (for example, a polymer electrolyte fuel cell) that generates an electric power and water by causing an electrochemical reaction between hydrogen gas in the reformed gas and oxygen gas in the air taken from outside, and the fuel cell It contains water tanks and pumps for supplying cooling water, and auxiliary equipment such as valves. Furthermore, a DC / DC converter that converts electric power (direct current) from the fuel cell into a high voltage, a control device, a PG burner that burns the reformed gas from the reformer until the fuel cell is in a power generation state at startup Components are also housed.
[0005]
[Problems to be solved by the invention]
The household fuel cell power supply device A is desirably small and compact. For this reason, the constituent members are accommodated in an exterior case (outer box) so as not to create a useless space. At this time, since the reformer operates in a high-heat atmosphere, consideration is given to storing it in an inner box and partitioning it from other components.
[0006]
The reformer in the reformer is provided with a burner at the lower portion, and a part of the fuel gas is supplied to the burner at the time of start-up and burned. At that time, air must be supplied through a fan. . Since the reformer is housed in the inner box as described above, there is a problem in efficiently supplying air to the burner, and there is also a problem in the discharge of combustion exhaust gas from the burner. At start-up, the reformed gas is burned by the PG burner without being supplied to the fuel cell, but there is also a problem with the exhaust gas emission. Furthermore, during the power generation of the fuel cell, air (oxygen gas) taken in from the outside is supplied to the air electrode and reformed gas (hydrogen gas) is supplied to the fuel electrode to react. Unreacted hydrogen gas is used as fuel for the reformer burner, but unreacted oxygen gas is discharged from the fuel cell. The reaction in the fuel cell is an exothermic reaction, and since the temperature of the unreacted oxygen gas to be discharged is about 80 ° C., the discharge to the outside becomes a problem.
On the other hand, since the flue gas from the burner of the reformer and the flue gas from the PG burner are high temperature (450 to 700 ° C.), if these flue gas is discharged to the outside, there is a risk of causing burns or fire. is there.
[0007]
The present invention has been made to solve all of these conventional problems, and can efficiently supply air to the burner of the reformer, as well as combustion exhaust gas in the reformer burner and combustion exhaust gas in the PG burner, and An object of the present invention is to provide a fuel cell power supply device that can safely discharge unreacted oxygen gas from the fuel cell to the outside.
[0008]
[Means for Solving the Problems]
As technical means for achieving the above-mentioned object, the present invention includes a reformer for reforming raw fuel gas such as city gas into hydrogen-rich gas, which is housed in an inner box, together with the inner box, a PG burner, a fuel cell , A fuel cell power supply device in which equipment such as a water tank, pumps, and converter are housed in an outer box, wherein the inner box is provided with an intake hole for taking in air, and the outer box has an air intake port Is provided at the lower part of both side surfaces, and the gist of the fuel cell power supply apparatus is provided with an exhaust hole for discharging exhaust gas generated inside at the upper part on the front side .
In this fuel cell power supply device ,
A duct is connected to the exhaust hole in the outer box, and combustion exhaust gas generated in the reformer of the reformer, combustion exhaust gas generated in the PG burner, and unreacted oxygen gas discharged from the fuel cell Merging with the duct and discharging from the exhaust hole;
Also, a metal cover is attached to the front part of the exhaust hole,
It is characterized by.
[0009]
In the present invention, an air intake hole is provided in the inner box housing the reformer, so that the air flowing in from the air intake hole is preheated in a high heat atmosphere and supplied to the burner of the reformer via the fan. it can. Since the outer box is provided with an air intake port, the air flowing in from the air intake port can be fed into the intake hole of the inner box. Combustion exhaust gas generated in the reformer burner, combustion exhaust gas generated in the PG burner, and unreacted oxygen gas discharged from the fuel cell are collected in a duct disposed in the outer box, and are exhausted in the outer box. Discharged from. Since a metal cover is attached to the front portion of the exhaust hole, the high-temperature combustion exhaust gas comes into contact with the cover and is cooled, and the exhaust gas temperature can be lowered.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of a fuel cell power supply device according to the present invention will be described with reference to the accompanying drawings. In FIG. 1, reference numeral 1 denotes a fuel cell power supply device, in which necessary components are housed inside an outer box 2 that is an outer case. A horizontally long exhaust hole 3 (FIG. 2) is provided in the upper part on the front side of the outer box 2, and a duct 4 connected to the exhaust hole 3 is disposed in the upper part in the outer box 2. In front of the exhaust hole 3, a metal cover material 5 having a good thermal conductivity is attached horizontally, and a slit-shaped hole 5 a is provided in parallel at a position corresponding to the exhaust hole 3. A louver-like air intake 6 is provided at the lower part of both side surfaces of the outer box 2.
[0011]
Reference numeral 7 denotes an inner box containing the reformer, which is installed near the left end as viewed from the front side in the outer box 2, and has one or more intake holes 8 for taking in air at the upper end. It is provided in the place. The reformer accommodated in the inner box 7 includes a desulfurizer 9, a reformer 10, a CO converter 11, and a CO remover 12 as shown in FIGS. 3 and 4.
[0012]
The reformer 10 is provided with a burner 10a in the lower part, and a part of the fuel gas is supplied to the burner 10a at the start-up, and air is supplied by a fan 10b attached to the lower end of the inner box 7 and burns. Then, the temperature of the catalyst charged in the reformer 10 is increased to an appropriate temperature (650 to 700 ° C.). The supply of air to the burner 10a is such that the air flowing in from the air intake 6 of the outer box 2 flows into the inside through the intake hole 8 of the inner box 7 and is sucked by the fan 10b and sent into the burner 10a. Done in If it does in this way, the air which flowed into the inner box 7 will be pre-heated in a high temperature atmosphere, the warm air will be supplied to the burner 10a with the fan 10b, and thermal efficiency will improve. The combustion exhaust gas in the burner 10a flows into the duct 4 through the exhaust top 7a provided at the upper end of the inner box 7.
[0013]
The raw fuel gas such as city gas supplied to the fuel cell power supply device 1 enters the desulfurizer 9 in the inner box 7 and is sent to the reformer 10 after the sulfur content is removed. At this time, water is supplied from a water tank, which will be described later, and steam vaporized by the vaporizer 13 is mixed therein. The reformer 10 performs steam reforming of the fuel gas to generate a reformed gas containing hydrogen, carbon dioxide, and carbon monoxide.
[0014]
This reformed gas is supplied to the CO converter 11 and carbon monoxide contained in the reformed gas is converted into carbon dioxide. Next, the reformed gas is supplied from the CO converter 11 to the CO remover 12, and the concentration of carbon monoxide contained in the reformed gas is reduced by selective oxidation. Since carbon monoxide poisons the fuel cell catalyst, the concentration is preferably 10 ppm or less.
[0015]
In this way, the fuel gas is reformed into a hydrogen-rich gas by the reformer in the inner box 7, but the temperature of each reactor of the reformer is not stable at the start-up, and a high-quality reformed gas cannot be obtained. Therefore, it cannot be supplied to the fuel cell 15 (fixed near the middle of the right end portion when viewed from the front side in the outer box 2). Therefore, the reformed gas is sent to the PG (process gas) burner 16 installed near the center in the outer box 2 and combusted until each reactor is stabilized. The combustion exhaust gas from the PG burner 16 flows into the duct 4 through the exhaust top 16a.
[0016]
When the reformer is stabilized, the supply of the reformed gas to the PG burner 16 is shut off, and the reformed gas is supplied to the fuel cell 15 to generate power. In this case, the fuel cell 15 is a polymer electrolyte fuel cell, and includes a fuel electrode 15a and an air electrode 15b as shown in FIG. 5, and the reformed gas is supplied to the fuel electrode 15a. The hydrogen gas in the reformed gas supplied to the fuel electrode 15a and the oxygen gas in the air supplied to the air electrode 15b undergo an electrochemical reaction through the solid polymer electrolyte membrane to generate electric power and water. Is done. The air supplied to the air electrode 15b is supplied via an air pump 17 attached below the fuel cell 15, and the air taken in from the air intake 6 of the outer box 2 is sent. The unreacted air (oxygen gas) at the air electrode 15b of the fuel cell 15 flows into the duct 4 via the conduit 15d (FIG. 4).
[0017]
Since the fuel cell 15 generates heat in the electrochemical reaction during operation, cooling water is supplied from the water tank 18 disposed in the vicinity of the fuel cell 15 to the cooling unit 15c of the fuel cell 15 via the water pump 19. Cooling. The cooled water is returned to the water tank 18 and circulated for use. However, since the amount of water in the water tank 18 gradually decreases, the city water is appropriately supplied and supplemented.
[0018]
A plurality of water pumps 20 are installed adjacent to the water pump 19, and these water pumps 20 are the vaporizer 13, heat exchanger 14 (FIG. 5) of the reformer, the CO converter 11, Water is supplied from the water tank 18 to each heat exchanger provided on the outlet side of the CO remover 12.
[0019]
A plurality of gas pumps 21 (FIG. 1) are installed above the water pumps 19, 20. These gas pumps 21 are used for supplying fuel gas to the reformer 10, supplying air to the PG burner 16, and the like. Used as
[0020]
As described above, the pumps such as the water pumps 19 and 20 and the gas pump 21 are arranged at a position apart from the reformer in the high temperature atmosphere so that they are not affected by heat as much as possible. . Valves are also installed collectively at a position away from the reformer, for example, near the fuel cell 15.
[0021]
A DC / DC converter 22 is installed above the fuel cell 15, boosts the direct-current voltage generated by the fuel cell 15 to about 180 V, and sends it to the DC / AC inverter B. A control device (not shown) is also installed near the DC / DC converter 22.
[0022]
By the way, the burner 10a of the reformer 10 is supplied with fuel gas at the time of startup, and the fuel gas supply is cut off when the fuel cell 15 enters normal operation. Combustion is continued in order to maintain the catalyst charged in the inside at a predetermined temperature. The fuel necessary for this is supplied by sending unreacted reformed gas discharged from the fuel electrode 15a of the fuel cell 15 to the burner 10a.
[0023]
The combustion exhaust gas in the burner 10a flows into the duct 4 through the exhaust top 7a of the inner box 7 as described above, and is discharged outside through the duct 4 from the exhaust hole 3 of the outer box 2. The combustion gas of the reformed gas combusted by the PG burner 16 at the start-up also flows into the duct 4 through the exhaust top 16a, and further unreacted air (oxygen) discharged from the air electrode 15b during operation of the fuel cell 15. Gas) also flows into the duct 4 via the pipe line 15d. Accordingly, all of these exhaust gases merge into the duct 4 and are discharged from the exhaust hole 3 of the outer box 2.
[0024]
Exhaust gas having a considerably high temperature is discharged from the discharge hole 3, but the temperature of the exhaust gas is lowered because the metal cover member 5 is attached to the front portion of the discharge hole 3 as described above. That is, the hot exhaust gas contacts the cover material 5 and is cooled. Since the cover material 5 is formed in a horizontally long shape, the heat heated by the exhaust gas convects to the end and dissipates heat. Therefore, the temperature of the cover material 5 does not increase abnormally. Further, the exhaust gas is partially flowed by the cover material 5, whereby the heat of the exhaust gas is dispersed. It is preferable that a heat exchanger is provided between the exhaust top 7a of the inner box 7 and the duct 4 and between the exhaust top 16a of the PG burner 16 and the duct 4 to lower the temperature of the combustion exhaust gas before discharging.
[0025]
In this case, the cover material 5 can not only conceal the exhaust holes 3 and improve the appearance, but also can exhibit a decorative function by providing a design such as a pattern on the surface side. In particular, it is possible to enhance the beauty because it is a spot that is easily noticeable at the upper part on the front side of the outer box 2.
[0026]
The air intake 6 is located at the lower side of the side of the outer box 2 and is away from the exhaust hole 3, and the combustion exhaust gas diffuses upward, so that the exhausted exhaust gas is discharged from the air intake 6 into the outer box 2. Will not be taken into. The air taken into the outer box 2 from the air intake port 6 on the right side of the outer box 2 passes through the pumps, water tank, fuel cell, DC / DC converter, etc. while cooling, and passes through the intake hole 8. It flows into the box 7. The air flowing into the inner box 7 is preheated in a high temperature atmosphere by the reformer as described above, and then supplied to the burner 10a of the reformer 10 by the fan 10b.
[0027]
【The invention's effect】
As described above, the fuel cell power generator according to the present invention has an intake hole in the inner box housing the reformer, and preheats the air flowing in from the intake hole in a high temperature atmosphere to the burner of the reformer. Since it supplies, thermal efficiency can be improved. Since the air intake is provided in the lower part of both side surfaces and the exhaust hole is provided in the upper part on the front side , the combustion exhaust gas does not flow into the outer box from the air intake. The combustion exhaust gas generated by the reformer burner and the PG burner and the unreacted air (oxygen gas) discharged from the fuel cell all merge into a duct disposed in the outer box and are discharged from the exhaust hole of the outer box. be able to. By attaching a metal cover material to the front part of the exhaust hole, it is possible to cool the high-temperature combustion exhaust gas at the time of discharge and to prevent dangers such as burns and fires.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of a fuel cell power supply device according to the present invention. FIG. 2 is a schematic exploded perspective view of the vicinity of an exhaust hole in an outer box. FIG. FIG. 4 is a schematic perspective view of the main part of the fuel cell power supply apparatus. FIG. 5 is a block diagram of the entire system including the fuel cell power supply apparatus. FIG. ]
DESCRIPTION OF SYMBOLS 1 ... Fuel cell power supply device 2 ... Outer box 3 ... Exhaust hole 4 ... Duct 5 ... Cover material 6 ... Air intake 7 ... Inner box 8 ... Intake hole 9 ... Desulfurizer 10 ... Reformer 11 ... CO converter 12 ... CO remover 13 ... Vaporizer 15 ... Fuel cell 16 ... PG burner 17 ... Air pump 18 ... Water tank 19, 20 ... Water pump 21 ... Gas pump 22 ... DC / DC converter

Claims (3)

A reformer that reforms raw fuel gas such as city gas into hydrogen-rich gas is stored in the inner box, and devices such as PG burners, fuel cells, water tanks, pumps, and converters are stored in the outer box along with this inner box. In the fuel cell power supply apparatus, the inner box is provided with an intake hole for taking in air, and the outer box is provided with an air intake port at the lower part of both side surfaces, and exhausts exhaust gas generated inside. A fuel cell power supply device provided with an exhaust hole in the upper part on the front side . A duct is connected to the exhaust hole in the outer box, and combustion exhaust gas generated in the reformer of the reformer, combustion exhaust gas generated in the PG burner, and unreacted oxygen gas discharged from the fuel cell The fuel cell power supply device according to claim 1, wherein the fuel cell power supply device is joined to the duct and discharged from the exhaust hole. The fuel cell power supply device according to claim 1 or 2, wherein a metal cover member is attached to a front portion of the exhaust hole.

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