JPH0280301A - Fuel reforming apparatus for fuel cell and power generating apparatus using the fuel cell - Google Patents

Abstract

PURPOSE:To improve compactness and heat transmitting characteristic of a fuel cell efficiently and inexpensively by connecting directly a fuel reforming apparatus constructed by laminating plural layers of specified composite reforming plates to the fuel cell through a common manifold. CONSTITUTION:A composite reforming plate 11 is constructed by arranging a gas impermeable plate 12, a conducting groove 13 for raw material gas 3 for reforming which is formed orthogonally on both surfaces of the gas impermeable plate 12, a conducting groove 15 for reformed fuel gas, reforming catalyst 14 in the groove 13, and combustion catalyst 16 in the groove 15. Then, a laminated body 10 is formed by building the reforming plate 11 in layers interposing a separating plate 21. A fuel reforming apparatus 20 is then constructed by attaching each manifold such as an inlet 17A of a raw material gas 3, inlet 18A of reformed fuel, outlet 18B, etc., to side surfaces of the laminated body 10. Thereafter, a power generating apparatus using the fuel cell is obtd. by connecting a fuel cell 2 to the apparatus 20 through the manifold 17B housing a heat exchanger therein, directly. Finally, raw material gas 3 for reforming contg. hydrocarbons is fed to the apparatus 20 and passed through the conducting groove 13, and power generating reaction is caused by introducing generated H2-rich reformed gas into the fuel gas groove of the fuel cell 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel reformer and a fuel cell that reform hydrocarbons such as natural gas and methanol into hydrogen-rich reformed gas and supply the reformed gas to a fuel cell. Regarding power generation equipment.

[Conventional technology]

Fuel cell power generation equipment has many advantages such as high efficiency and environmental friendliness.
i, and efforts are being made to put it into practical use as a cogeneration device. As shown in FIG. 5, which shows a gas flow diagram of the conventional device, the fuel reformer 1, which is the main component of the fuel cell power generation device, catalyzes hydrocarbons in the reforming raw material 3 such as natural gas and methanol. Let it react with water vapor,
This is a device that converts the reformed gas 4 into hydrogen concentration enough to be used in the fuel cell 2 and sends it to the fuel cell 2 via a pipe 6.

The steam reforming reaction of hydrocarbons is expressed by the following equation in the case of methane.

CH+2HO→CO2+4H2・・・・・・・・・ (
1) In the case of methanol, it is expressed by the following formula.

CH30H+H20→CO2+3H2・・・・・・・・・
・(2) Since both of the above reactions are large endothermic reactions,
Hydrogen that was not used for power generation in fuel cell 2 is converted into off-gas 4
B is sent to the reformer through the pipe 7 and burned in the nocuna IB to serve as its heat source. Further, off-air 5B of the reaction air 5 is also sent to the burner and used for combustion.

[Problem to be solved by the invention]

Conventional fuel reformers are of the stratified type, such as in chemical plants, in which a single or double reforming reaction tube filled with a reforming catalyst is installed in a combustion furnace with a nose. The heat required for the reforming reaction was supplied by convective heat transfer from the combustion gas or radiant heat transfer during combustion. However, this type of reformer requires a large furnace volume for combustion, and the amount of catalyst cannot be reduced below a certain level due to the rate-limiting heat transfer inside the reaction tube filled with the reforming catalyst. This impedes the compactness required for a reformer for industrial use.

As an improvement plan for these, a method using a combustion catalyst instead of a combustion burner has been proposed (Japanese Patent Laid-Open No. 58-231).
(Refer to Japanese Patent Application No. 68), this also cannot escape from the heat transfer rate limitation on the reforming catalyst side because the conventional reaction tube is filled with a catalyst.

On the other hand, as a methanol reformer, the reforming catalyst is arranged in the form of a plate to make it compact.
86204 (see Japanese Patent Publication No. 86204) and one in which combustion catalysts are alternately stacked (see Japanese Unexamined Patent Application Publication No. 1986-74504), the point is that this also uses a conventional catalyst filled in the case. has the same drawbacks as above.

In addition, fuel cells are required to have responsiveness that can quickly respond to electrical load demands, but the reformer 1 and fuel cell 2
Because the fuel cells are connected via long pipes 6, there is a time delay for the reformed gas to move through the pipes 6, especially when using a fuel cell as a mobile power source that starts and stops frequently. There is a problem in that the load followability of the fuel cell is inhibited by this travel time delay.

An object of the present invention is to provide a fuel reformer that is compact enough to be suitable for a fuel cell power generation device, has excellent heat transfer characteristics for the reaction heat necessary for the reforming reaction, and has a small movement time delay of reformed gas. An object of the present invention is to obtain a fuel cell power generation device equipped with a device.

[Means to solve the problem]

In order to solve the above problems, according to the present invention, in a device that steam-reforms hydrocarbons in a reformed raw material and supplies hydrogen-rich reformed gas to a fuel cell, both sides of a gas impermeable plate are provided with The reforming material gas distribution groove and the reformed fuel gas distribution groove are respectively formed in orthogonal directions, and the reforming material gas distribution groove is supported on a gas impermeable plate so as to be in contact with the gas flow inside the reforming material gas distribution groove. and a combustion catalyst active in the combustion reaction of the reformed fuel gas supported on a gas impermeable plate so as to be in contact with the gas flow in the reformed fuel gas flow groove. The reformed gas outlet side of the fuel reformer is directly connected to the reformed gas inlet side of the fuel cell via a common manifold, and a common manifold is installed as necessary. A heat exchanger that controls the temperature of the reformed gas may be included inside the unit, or a fuel reformer and a fuel cell connected via a common manifold may be used as a basic module, and this basic module may be combined with multiple modules. do.

[Effect]

In the above means, the composite catalyst plate is configured to support the reforming catalyst and the combustion catalyst in contact with the reforming raw material gas and the reformed fuel gas flowing in directions orthogonal to each other on both sides of the composite catalyst plate. The combustion heat of the reformed fuel generated on the combustion catalyst side can be supplied as the reaction heat necessary for the steam reforming reaction on the reforming catalyst side by using the thermal conductivity of the substrate. In addition to being able to efficiently supply reaction heat without being restricted by the heat transfer rate limitations of conventional devices using reaction tubes, the steam reforming device can be made more compact by eliminating the need for a burner and its heat exchange space.

Furthermore, if the exit side of the reformed gas of the fuel reformer is connected to the fuel cell through a common fuel gas manifold, the time delay in movement of the reformed gas can be shortened and the load followability of the fuel cell can be improved. Furthermore, if a heat exchanger is provided in a common manifold, it becomes possible to match the temperature of the reformed gas by the operating temperature of the fuel cell. Further, by combining directly connected devices as a basic module and combining a plurality of modules as necessary, compact fuel cell power generation devices with various capacities can be obtained.

〔Example〕

The present invention will be explained below based on examples.

FIG. 1 is a perspective view showing a fuel reformer according to an embodiment of the present invention. This is a simplified illustration of the main parts of the laminate. In the figure, 11 is a composite reforming plate, which includes a gas impermeable plate 12, a flow groove 13 for reforming raw material gas (including water vapor) 3 formed on both sides of the plate in directions orthogonal to each other, and reformed fuel. The gas (mixed gas of off-gas 4B and reaction air 5) mis, the reforming catalyst 14 supported by the gas-impermeable plate 12 in the flow groove 13, and the reforming catalyst 14 supported by the gas-impermeable plate 12 in the flow groove 15. A laminate 10 of composite reforming plates is constructed by stacking a plurality of layers of composite reforming plates 11 with separate plates 21 in between.
is formed. The stacked body 10 configured in this manner has a structure similar to that of a fuel cell. Therefore, one manifold (not shown) is provided on each of the two pairs of opposing sides of the stacked body 10, and the flow grooves 13 are provided with a manifold (not shown). The reformed raw material gas 3, such as natural gas or alcohol vapor mixed with water vapor, is sent to the flow groove 15 side as a reformed fuel, and a mixed gas of off-gas 4B and off-air 5B from the fuel cell is combusted. Combustion reaction of off-gas 4B on the catalyst 16 side,
A steam reforming reaction of the reforming raw material gas 3 on the reforming catalyst 14 side is performed simultaneously using the combustion heat generated by the combustion reaction.

The composite reforming plate 11 has a gas impermeable plate 12 depending on the reforming raw material.
For example, in the case of natural gas, gas passages are provided on both sides of a ceramic plate such as cordierite or alumina.

Further, a nickel-based reforming catalyst 14 is supported on the flow groove 13 side, and a noble metal catalyst such as platinum or palladium is supported on the flow groove 15 side. This composite reforming plate is laminated with separators 21 such as stainless steel plates interposed therebetween in accordance with the amount of gas to be processed required for the fuel cell, and is placed in a case (not shown) to form a reforming device. The reformed raw material 3, which is a mixture of natural gas and steam, which is a reformed raw material, receives combustion heat from a combustion catalyst 14 while passing through a flow path 13, and is output as a hydrogen-rich reformed gas 4. As can be seen from this figure, in the present invention, the conventional concept of a reaction tube is eliminated, and the gas passage itself serves as the reforming catalyst, so it is completely free from the heat transfer rate limitation in the reforming catalyst layer. Another advantage is that catalytic combustion is carried out on the opposite side of the same gas-impermeable plate, so the heat of combustion is transferred by conduction. Furthermore, combustion of off-gas is also carried out by a combustion catalyst in the gas passage, eliminating the need for space in a combustion furnace and resulting in a compact reformer.

FIG. 2 is a perspective view showing a state in which the fuel reformer according to the above-described embodiment is combined with a fuel cell, and FIG. 3 is a plan view of FIG. 2 viewed from above. In the figure, an inlet manifold 17A% for the reforming raw material 3 is located on the side of the stacked body 10 of the composite reforming plate.
The fuel reformer 20 has an inlet manifold 18N and an outlet manifold 18B for the reformed fuel airtightly attached to the sides perpendicular thereto. A common manifold 17B that is directly connected to the side surface of the fuel cell 1 is configured to also serve as an inlet side manifold for the reformed gas 4 of the fuel cell 1, and off-gas 4B whose hydrogen concentration has decreased due to the power generation of the fuel cell 1 is transferred to the outlet side manifold 4B. and piping 7
The reformed fuel manifold 1 of the fuel reformer 20 via C
Flows into 8A. In addition, the reaction air 5 that has flowed into the fuel cell 1 via the inlet manifold 88 is transferred as off-air 5B to the reformed fuel manifold 18A of the fuel reformer 20 (along with the off-gas 4B) via the outlet manifold 5B [and distribution W8C]. The residual hydrogen in the off-gas 4B is combusted by flowing into the combustion catalyst 16 in FIG. Auxiliary fuel 9 is supplied.

As described above, the reformed gas generated by the reformed raw material gas 3 passing through the flow groove 13 of the fuel converter 20 is directly supplied to the fuel gas groove of the fuel cell 1 by the common manifold 17B without passing through any piping. By flowing in and contributing to the power generation reaction, it is possible to significantly shorten the travel time delay that conventionally occurs within the piping, making it possible to obtain a fuel cell power generation system with excellent followability to load fluctuations, and to save money by omitting piping. A compact fuel cell power generation device that takes up less space can be obtained.

FIG. 4 is a plan view showing a simplified main part of a different embodiment of the present invention, in which the heat exchanger 30 is housed in a common manifold 17B that connects the fuel reformer 2o and the fuel cell 2. However, unlike the above embodiment, if the temperature of the reformed gas is higher than the operating temperature of the fuel cell 1, for example, room temperature reaction air 5 is used as the cooling medium of the heat exchanger 30 to adjust the temperature of the reformed gas to the fuel cell. Since it is possible to control the temperature of the reaction air so as to bring it close to the operating temperature of the fuel cell 1 and at the same time to bring the temperature of the reaction air close to the operating temperature of the fuel cell 1, it is possible to obtain a fuel cell power generation device with high thermal efficiency.

On the other hand, as shown in Figure 2 or Figure 4, by combining multiple power generation devices with fuel reformers directly connected to fuel cells as a basic module to create a large capacity power generation device, the basic module is almost a rectangular parallelepiped. Taking advantage of this fact, an advantage can be obtained that a compact, large-capacity power generation device can be formed.

[Effects of the Invention] As described above, the present invention includes a composite reforming plate in which a reforming catalyst 2 and a combustion catalyst are disposed in each of the reforming material and reformed fuel flow grooves formed on both sides of the gas impermeable plate. Laminated - formed the main part of the fuel reformer.

As a result, the combustion heat generated on the combustion catalyst side is efficiently transferred to the reforming catalyst by thermal conduction, and this combustion heat is used as a heat source for the steam reforming reaction, which is an endothermic reaction. This eliminates the need for a combustion furnace, making the reformer more compact, and since the gas passage is formed of the reforming catalyst layer, heat transfer within the reforming catalyst layer, which was a problem with conventional technology, is achieved. This has the advantage of being completely freed from rate-determining, and based on this, the amount of reforming catalyst can be reduced.

In addition, if the reformed gas outlet side of the pyrotechnic reformer configured in this way is directly connected to the reformed gas inlet side of the fuel cell via a common manifold, the reformed gas supply It is possible to provide a power generation device that saves space by omitting piping, and because the time required for reformed gas to move through the piping is significantly shortened, it has excellent ability to follow fluctuations in the power required by the load. A power generation device can be obtained.

Furthermore, by providing a heat exchanger in a common manifold, it is possible to control the difference between the reformed gas temperature and the operating temperature of the fuel cell, and use the obtained thermal energy as a heat source to preheat reaction air, for example. It can be used as

2. By combining multiple power generating devices configured as described above as a basic module, it is possible to provide a compact high-capacity power generating device by taking advantage of the fact that the power generating device is almost a rectangular parallelepiped. .

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a fuel reformer for a fuel cell according to an embodiment of the present invention, FIG. 2 is a perspective view showing a state in which the fuel reformer shown in FIG. 1 is combined with a fuel cell, and FIG. The figure is a plan view of FIG. 2 viewed from above, FIG. 4 is a plan view of main parts showing a different embodiment of the present invention, and FIG. 5 is a gas flow diagram showing a conventional device. 1.20.・Fuel reformer, 2...Fuel cell, 3...
Reforming raw material (gas), 4... Reformed gas, 4B... Off gas, 5... Reaction air, 5B... Off air, 7B, 8
A. 8B... Manifold, 10... Composite modification plate laminate, 11... Composite modification plate, 12... Gas impermeable plate,
13. ,. Distribution groove (reforming raw material side), 14... reforming catalyst, 15...
Distribution groove (reformed fuel side), ... combustion catalyst, 3rd flash, Ertufu District, Ge District

Claims (1)

[Scope of Claims] 1) In a device that steam-reforms hydrocarbons in a reforming raw material to supply a hydrogen-rich reformed gas to a fuel cell, the gas-impermeable plates are formed on both sides of the gas-impermeable plate in directions perpendicular to each other. a reforming catalyst supported on a gas impermeable plate so as to be in contact with the gas flow in the reforming material gas circulation groove; A plurality of composite reforming plates having a combustion catalyst active in the combustion reaction of the reformed fuel gas supported on a gas impermeable plate so as to be in contact with the gas flow in the reformed fuel gas distribution groove are laminated. A fuel reformer for a fuel cell characterized by: 2) A fuel reformer for a fuel cell according to claim 1, wherein the reformed gas outlet side of the fuel reformer is directly connected to the reformed gas inlet side of the fuel cell via a common manifold. fuel cell power generation device. 3) Claim 2, characterized in that the common manifold houses a heat exchanger therein for controlling the temperature of the reformed gas.
The fuel cell power generation device described. 4) The fuel cell power generation device according to claim 2 or 3, wherein a fuel reformer and a fuel cell connected via a common manifold are used as a basic module, and a plurality of basic modules are combined.