JP2769556B2 - Fuel cell generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a fuel cell power generator, and more particularly to a fuel cell power generator that provides long-term stable power.

(Prior Art) As a fuel for a fuel cell, a gaseous fossil fuel containing methane as a main component such as methanol fuel or natural gas or city gas is widely used. Methanol has the advantage of being easy to store and handle because it is a liquid, and has the advantage that the reformer has a simple structure.On the other hand, it has disadvantages such as the need to periodically refuel during continuous operation. Therefore, it is mainly used for remote islands where supply of city gas is difficult, or for small fuel cell power generators.

FIG. 3 shows a configuration diagram of a fuel cell power generation apparatus using methanol as a fuel. Methanol M mixed at a predetermined ratio with water required for the reforming reaction is sent to a vaporizer 2 by a pump 1 and vaporized, and then enters a reformer 3. The reformer 3 is filled with, for example, a copper-chromium-based or copper-zinc-based reforming catalyst to reform methanol into a gas R rich in hydrogen. Since the reforming reaction is an endothermic reaction, the temperature of the catalyst is maintained at 200 to 300 ° C. by burning the exhaust gas S from the fuel electrode 5 of the fuel cell 4. By appropriately selecting the mixing ratio of methanol and water, the concentration of carbon monoxide in the reformed gas R can be reduced to 1% or less. It can be led directly to the fuel electrode without the need.

On the other hand, in the case of natural gas and city gas, fuel can be easily supplied only by gas piping and there is no need to store a large amount of fuel. I have.

FIG. 4 shows a configuration diagram of a fuel cell power generation device when city gas is used as fuel. After passing through the flow control valve V, the city gas A as the fuel is mixed with the hydrogen-rich reformed gas R and enters the desulfurizer 6. Here, after removing sulfur in the form of hydrogen sulfide, it is mixed with steam H and enters the reformer 7. The reformer 7 is filled with, for example, a nickel-based catalyst to reform the fuel A into a gas Q rich in hydrogen.

The amount of heat required for the reforming reaction is supplied by burning exhaust gas S from the fuel electrode 5 of the fuel cell 4 together with air O in a burner in the reforming apparatus, and is supplied at about 800 ° C. suitable for the reforming reaction.
Maintain the temperature. Gas Q leaving reformer 7 is about 15%
Carbon monoxide, and directing the fuel cell as it is would poison the platinum catalyst of the fuel electrode. For this reason, the carbon monoxide is passed through high-temperature and low-temperature two-stage carbon monoxide converters 8 and 9 to reduce the carbon monoxide concentration to 1% or less. The gas R thus formed is supplied to the fuel cell 4 via the flow control valve V, and a part of the gas R is branched and supplied to the upstream of the desulfurization device 6 described above.

(Problems to be Solved by the Invention) By the way, in the case of a fuel cell device using city gas as fuel, fuel can be easily supplied only by gas piping as described above. Distribution may be stopped, which is a serious problem when used in a power generation device that needs to supply power without interruption for a long time, for example, a power supply for communication. To solve this,
Although it is conceivable that the above-mentioned methanol is used as a reserve fuel, as shown in FIGS. 3 and 4, the city gas and the methanol greatly differ from each other in terms of the reforming catalyst, the reforming temperature, and the reforming apparatus. It is necessary to equip different types of reformers.

FIG. 5 is a configuration diagram showing the example. In normal times, continuous operation is performed using city gas, and when the supply of city gas is stopped for some reason, the system is switched to a system for reforming methanol M as a spare fuel. In such an apparatus configuration, when an operation method is adopted in which the methanol reformer 3 is normally stopped and activated when the supply of the city gas is stopped, the methanol reforming catalyst reaches a predetermined temperature. Since it takes about one hour to reach, the reformed gas R cannot be continuously supplied to the fuel cell 4. As a method for solving this problem, if the method of always burning the exhaust gas S in the methanol reformer and raising the catalyst temperature of the unused methanol reformer to the operating temperature from the normal time is used, It consumes a lot of fuel and causes great economic loss.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a fuel cell power generator capable of switching fuel from city gas to methanol as a reserve fuel without instantaneous interruption without wasteful consumption of fuel. The purpose is to:

(Means for Solving the Problems) In order to achieve the above object, a fuel cell power generator according to the present invention includes a reformer used for emergency containing a methanol reforming catalyst inside, and a city gas or natural gas inside. What is claimed is: 1. A fuel cell power generator, comprising: a reformer containing a gas reforming catalyst; and a fuel cell that is supplied with a gas reformed by the reformer and generates electric power. The present invention is characterized in that the reformer used for emergency with the reforming catalyst for methanol stored therein is always heated by using the exhaust heat of the reformer storing the reforming catalyst for methanol.

As described above, the present invention has two reformers for city gas / natural gas and methanol, and utilizes exhaust heat of a reformer in which a city gas or natural gas reforming catalyst is housed. The main feature is that the reformer used in an emergency in which the methanol reforming catalyst is housed inside is always heated.

As described above, in the conventional technology, the two reformers need to be provided with devices for heating the catalyst independently, and the reformer used in normal times is switched to the spare reformer without an instantaneous interruption. In order to perform the switching, it is necessary to keep the spare reformer at a predetermined temperature by using extra fuel even in normal times. In the present invention, paying attention to the fact that the operating temperature of the methanol reforming catalyst is 200 to 300 ° C. lower than that for city gas, and utilizing the exhaust heat from the city gas reformer that is normally used. As a result, the spare reformer is heated to a predetermined temperature, so that useless consumption of fuel can be suppressed.

(Example) The present invention will be described with reference to the drawings. FIG. 1 is a diagram for explaining a first embodiment of the present invention. In the figure, the components up to the reformers 7 and 3 are the same as those in FIG.

Exhaust gas T from the reformer 7 for city gas or natural gas is sent to exhaust heat recovery equipment 10 such as various kinds of residual heat equipment and a turbo compressor via a valve 21, and also to a methanol reformer 7 via a valve 22. Also sent to 3.

The exhaust pipe of the methanol reformer is connected to the exhaust heat recovery device 10 via the valve 29.

During normal times when city gas is used as fuel, exhaust gas S from the fuel electrode 5 passes through the valve 23, and air passes through the valve 24 into the city gas reformer 7, where it is burned by the burner and reformed catalyst. Is heated to a predetermined temperature. The city gas desulfurized and added with steam is reformed in the reformer 7 and guided to the carbon monoxide converters 8 and 9. The exhaust gas T that has exited the reformer 7 is led to the exhaust heat recovery device 10 through the valve 21 to recover the exhaust heat energy. Further, the opening / closing degree of the valve 22 for maintaining the temperature of the methanol reforming catalyst on standby at a predetermined temperature is adjusted to control the amount of the exhaust gas T introduced into the methanol reforming apparatus 3. At this time, since the burner of the methanol reformer 3 is not used, the valves 27 and 28 are closed. When the supply of the city gas A is stopped and the fuel cell is switched to the methanol M as the spare fuel, the valve 26 is opened and the methanol M obtained by mixing water at a predetermined ratio is introduced into the methanol reformer 3. Further, the valves 27 and 28 are opened to burn the exhaust gas S from the fuel electrode 5 in the reformer 3 and heat it. When the combustion is stabilized, the valves 23 and 24 are closed, the heating by the reformer 7 is stopped, and the valves 21 and 22 are also closed. Through a series of these operations, the fuel can be switched while the stable supply of the reformed gas to the fuel electrode of the fuel cell is performed.

As an application of this embodiment, there is an example in which a reformer for city gas and a methanol reformer in which a burner part is omitted are configured. In this example, even when reforming methanol fuel, the burner of the reformer for city gas is operated and the heat required for the reforming reaction is supplied indirectly. The structure of the reformer is simplified.

FIG. 2 shows a second embodiment of the present invention. The city gas reformer 7 and the methanol reformer 3 are connected by a heat pipe 30 which is a good heat conductor. During normal times using city gas A as fuel, the exhaust gas S from the fuel electrode passes through the valve 23.
However, the air O passes through the valve 24, and the city gas reformer 7
And burns with a burner to heat the reforming catalyst to a predetermined temperature. A part of the exhaust heat generated at this time is led to the methanol reformer 3 on standby via the heat pipe 30 to heat the catalyst, so that even when the city gas is stopped, the methanol fuel is removed for the same reason as in the first embodiment. Can be switched smoothly. Also in this case, by using a methanol reformer having no burner as an application example, the apparatus can be further simplified.

(Effects of the Invention) As is apparent from the above description, the present invention has a configuration in which the catalyst of the reformer for the spare fuel is heated using the exhaust heat of the reformer used in normal times. 5, the fuel can be switched from city gas to methanol as a spare fuel without an instantaneous interruption, and power generation can be continued without wasteful consumption of fuel as in the technique shown in FIG.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of the present invention, FIG. 2 is a block diagram of another embodiment of the present invention, FIG. 3 is a block diagram of a conventional fuel cell power generator using methanol as fuel, FIG. 4 is a configuration diagram of a conventional fuel cell power generator using city gas as fuel, and FIG.
FIG. 1 is a configuration diagram of a fuel cell power generator using city gas as a normal fuel and methanol as a reserve fuel by combining conventional techniques. 3 ... Methanol solute unit, 4 ... Fuel cell, 7 ... Reformer for city gas, 30 ... Heat pipe, V ...
... Flow control valve.

Claims (1)

(57) [Claims] 1. An emergency reformer containing a reforming catalyst for methanol inside, a reformer containing a reforming catalyst for city gas or natural gas inside, and a reformer reformed by the reformer. And a fuel cell that receives the supplied gas and performs power generation, and uses the exhaust heat of a reformer that houses a reforming catalyst for city gas or natural gas inside the fuel cell power generator. A fuel cell power generator wherein a reformer used for emergency containing a reforming catalyst for methanol is always heated.