WO2013146149A1

WO2013146149A1 - Fuel cell module

Info

Publication number: WO2013146149A1
Application number: PCT/JP2013/056167
Authority: WO
Inventors: 俊幸海野; 修平咲間
Original assignee: Ｊｘ日鉱日石エネルギー株式会社
Priority date: 2012-03-26
Filing date: 2013-03-06
Publication date: 2013-10-03
Also published as: JP2013201054A; JP5939858B2

Abstract

A fuel cell module is provided with a reformer that generates reformed gas using hydrogen-containing fuel, a cell stack that generates power using the reformed gas, a housing that houses at least the reformer and the cell stack therein, and a desulfurizer that desulfurizes the hydrogen-containing fuel supplied to the reformer. The desulfurizer is mounted onto the housing so as to be thermally connected to the outer surface thereof.

Description

Fuel cell module

The present invention relates to a fuel cell module.

Conventionally, as a fuel cell module, a reformer that generates a reformed gas using a hydrogen-containing fuel, a cell stack that generates power using the reformed gas, and a casing that houses at least the reformer and the cell stack And a desulfurizer that desulfurizes the hydrogen-containing fuel supplied to the reformer is known.

For example, Patent Document 1 describes a fuel cell module that uses a desulfurizer isolated from a casing without heating. As a desulfurization catalyst of this desulfurizer, for example, a zeolite desulfurization catalyst supporting metal fine particles Etc. are used. For example, Patent Document 2 describes a fuel cell module that is used by heating a desulfurizer with the heat of exhaust gas from a cell stack.

JP 2009-032406 A JP 2006-309982 A

Here, in the fuel cell module described above, the desulfurization catalyst may be limited to a relatively expensive one such as a zeolite desulfurization catalyst, or the overall energy efficiency may be reduced due to a decrease in exhaust gas temperature. Therefore, in recent fuel cell modules, with increasing spread to homes and the like, it is strongly required to realize cost reduction while maintaining energy efficiency.

Accordingly, an object of one aspect of the present invention is to provide a fuel cell module capable of realizing cost reduction while maintaining energy efficiency.

In order to solve the above-described problems, a fuel cell module according to one aspect of the present invention includes a reformer that generates a reformed gas using a hydrogen-containing fuel, a cell stack that generates power using the reformed gas, and a modification. And a desulfurizer that desulfurizes the hydrogen-containing fuel supplied to the reformer, and the desulfurizer is thermally connected to the outer surface of the housing. Is attached.

In the fuel cell module according to one aspect of the present invention, since the desulfurizer is attached so as to be thermally connected to the outer surface of the casing, the desulfurizer is not heated by the heat of the exhaust gas. The desulfurizer can be heated by transferring heat from the cell stack, which has only been released from the body to the outside, from the casing to the desulfurizer. Therefore, it is possible to suppress a decrease in energy efficiency due to heating of the desulfurizer. In addition, since the desulfurizer can be heated and maintained at a high temperature in this way, it is possible to use a relatively inexpensive metal-based desulfurization catalyst that requires heating as the desulfurization catalyst. Therefore, according to one aspect of the present invention, cost reduction can be realized while maintaining energy efficiency.

Moreover, the desulfurizer may be attached to the outer surface of the housing via a heat insulating material. In this case, the heat transfer from the housing to the desulfurizer can be controlled by the heat insulating material, and as a result, the temperature of the desulfurizer can be controlled.

Further, the casing and the desulfurizer may be wrapped with a heat insulating material. In this case, the above effect, that is, the effect of heating the desulfurizer by transferring heat from the heat generated by the cell stack from the casing to the desulfurizer instead of heating the desulfurizer with the heat of the exhaust gas, is effective. Can be demonstrated.

Further, the desulfurizer has a flow path through which the hydrogen-containing fuel is circulated, and the flow path can exchange heat with each other between the inlet side through which the hydrogen-containing fuel flows and the outlet side through which the hydrogen-containing fuel flows out. It may be folded back. In this case, the temperature distribution of the desulfurizer can be made uniform, and the hydrogen-containing fuel can be suitably desulfurized.

According to one aspect of the present invention, it is possible to realize cost reduction while maintaining energy efficiency.

It is a schematic block diagram which shows the fuel cell module which concerns on one Embodiment. It is sectional drawing which shows the desulfurizer in the fuel cell module of FIG. It is a schematic perspective view for demonstrating the fuel cell module of FIG. It is a graph which shows the temperature distribution of the desulfurizer in the fuel cell module of FIG. 1 along a flow path. (A) is sectional drawing which shows the modification of the desulfurizer in the fuel cell module of FIG. 1, (b) is sectional drawing which shows the other modification of the desulfurizer in the fuel cell module of FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

FIG. 1 is a schematic block diagram showing a fuel cell module according to an embodiment of the present invention. As shown in FIG. 1, the fuel cell module 1 of this embodiment includes a housing 6 that houses at least a reformer 2, a cell stack 3, a combustion unit 4, and a water vaporizer 5.

The fuel cell module 1 generates power in the cell stack 3 using a hydrogen-containing fuel and an oxidant. The type of the cell stack 3 in the fuel cell module 1 is not particularly limited, and examples thereof include a polymer electrolyte fuel cell (PEFC), a solid oxide fuel cell (SOFC), and a phosphoric acid type. Fuel cell (PAFC: Phosphoric)
Acid FuelCell), Molten Carbonate Fuel Cell (MCFC)
Cell) and other types can be employed.

As the hydrogen-containing fuel, for example, a hydrocarbon fuel is used. As the hydrocarbon fuel, a compound containing carbon and hydrogen in the molecule (may contain other elements such as oxygen) or a mixture thereof is used. Examples of hydrocarbon fuels include hydrocarbons, alcohols, ethers, and biofuels. These hydrocarbon fuels are derived from conventional fossil fuels such as petroleum and coal, and synthetic systems such as synthesis gas. Those derived from fuel and those derived from biomass can be used as appropriate. Specific examples of hydrocarbons include methane, ethane, propane, butane, natural gas, LPG (liquefied petroleum gas), city gas, town gas, gasoline, naphtha, kerosene, and light oil.

In addition, methanol and ethanol are mentioned as alcohols. Examples of ethers include dimethyl ether. Examples of biofuels include biogas, bioethanol, biodiesel, and biojet. As the oxidizing agent, for example, air, pure oxygen gas (which may contain impurities that are difficult to remove by a normal removal method), or oxygen-enriched air is used.

The reformer 2 generates a reformed gas as a hydrogen rich gas (hydrogen containing gas) from the supplied hydrogen containing fuel. The reformer 2 reforms the hydrogen-containing fuel and generates a reformed gas by a reforming reaction using a reforming catalyst. The reforming method in the reformer 2 is not particularly limited, and for example, steam reforming, partial oxidation reforming, autothermal reforming, and other reforming methods can be employed. The reformer 2 may have a configuration for adjusting the properties in addition to the reformer reformed by the reforming catalyst depending on the properties of the hydrogen-rich gas required for the cell stack 3. For example, when the type of the cell stack 3 is a polymer electrolyte fuel cell (PEFC) or a phosphoric acid fuel cell (PAFC), the reformer 2 is configured to remove carbon monoxide in the hydrogen-rich gas. (For example, a shift reaction part and a selective oxidation reaction part). The reformer 2 supplies the reformed gas to the cell stack 3.

The cell stack 3 generates power using the reformed gas and oxidant from the reformer 2. The cell stack 3 supplies the reformed gas and the oxidant, which have not been used for power generation, to the combustion unit 4 as off-gas.

The combustion unit 4 burns off gas supplied from the cell stack 3 and heats the reformer 2 and the water vaporizer 5. The combustion unit 4 is located at the upper part of the cell stack 3. The combustor 4 is composed of, for example, a case. The reformed gas and the oxidant that have not been used for power generation are combusted in the case, and the reformer 2 and the water vaporizer 5 that are thermally connected to the case are provided. You may heat indirectly. Or the combustion part 4 is comprised without a case, for example, burns the reformed gas and oxidant which were not used for electric power generation at the upper part of the cell stack 3, and heats the reformer 2 and the water vaporizer 5 directly. May be. The exhaust gas generated by the combustion of the combustion unit 4 is exhausted outside the housing 6.

The water vaporizer 5 is an evaporator that heats and vaporizes supplied water to generate water vapor supplied to the reformer 2. The water vaporizer 5 supplies the generated steam to the reformer 2. Heating of the water in the water vaporizer 5 can use heat generated in the fuel cell module 1 such as recovering heat of the reformer 2, heat of the combustion unit 4, or exhaust gas. In the present embodiment, the water vaporizer 5 is disposed on the upper side of the combustion unit 4.

The housing 6 is a metal box having a rectangular parallelepiped shape, and has an internal space for accommodating at least the reformer 2, the cell stack 3, the combustion unit 4, and the water vaporizer 5.

Further, as shown in FIGS. 1 and 2, the fuel cell module 1 of the present embodiment includes a desulfurizer 7. The desulfurizer 7 has a long box-like outer shape, and desulfurizes the hydrogen-containing fuel supplied to the reformer 2. The desulfurizer 7 has a desulfurization catalyst 7x for removing sulfur compounds contained in the hydrogen-containing fuel. As the desulfurization method of the desulfurizer 7, for example, a hydrodesulfurization method in which a sulfur compound is removed by reacting with hydrogen is employed. The desulfurizer 7 supplies the desulfurized hydrogen-containing fuel to the reformer 2. As the desulfurization catalyst 7x, a metal desulfurization catalyst represented by Ni is used.

The desulfurizer 7 has a flow path 8 through which hydrogen-containing fuel flows. The flow path 8 is filled with the desulfurization catalyst 7x. The flow path 8 is folded back so that heat exchange can be performed between the inlet 8a side through which the hydrogen-containing fuel flows and the outlet 8b side through which the hydrogen-containing fuel flows out.

Specifically, in the flow path 8, an inlet portion 8 a is provided at the lower portion of one side surface 7 a of the desulfurizer 7, and an outlet portion 8 b is provided at the upper portion of the side surface 7 a of the desulfurizer 7. The inlet portion 8a side and the outlet portion 8b side in the flow path 8 are in contact with each other via a metal plate 7c extending in the longitudinal direction so as to vertically define the inside of the desulfurizer 7. Such a flow path 8 extends straight from the inlet portion 8a to the vicinity of the other side surface 7b, is then folded back toward the side surface 7a so as to wrap around upward, and extends straight to the outlet portion 8b.

Further, a diffusion layer 7y for diffusing the hydrogen-containing fuel is provided on each of the inlet 8a side and the outlet 8b side in the flow path 8. An inlet pipe 7d for flowing hydrogen-containing fuel into the inlet section 8a is connected to the inlet section 8a, and an outlet pipe 7e for flowing hydrogen-containing fuel to the outside of the outlet section 8b is connected to the outlet section 8b. Has been.

The desulfurizer 7 is disposed horizontally on the upper surface (outer surface) 6a of the housing 6 via a heat insulating material 9, and is attached so as to be thermally connected to the upper surface 6a of the housing 6. Specifically, the desulfurizer 7 is placed on the upper surface 6 a of the casing 6 so as to sandwich the heat insulating material 9 between the desulfurizer 7 and the casing 6. In other words, the housing 6, the heat insulating material 9, and the desulfurizer 7 are in contact with each other and are stacked in this order from the bottom to the top.

The heat insulating material 9 has a plate shape having a predetermined thickness, and spreads on the upper surface 6a of the housing 6 so as to include at least the desulfurizer 7 when viewed from above. That is, the heat insulating material 9 is interposed between the desulfurizer 7 and the housing 6 so that the desulfurizer 7 and the housing 6 do not directly face each other. In this heat insulating material 9, by appropriately setting the predetermined thickness, the amount of heat transferred from the housing 6 to the desulfurizer 7 can be controlled, and the temperature of the desulfurizer 7 can be maintained at a predetermined temperature. The thickness of the heat insulating material 9 here is set so that the desulfurizer 7 does not exceed the upper limit temperature, thereby improving safety and reliability. In addition, as the heat insulating material 9, the material and specification are not limited, A various thing can be used.

The casing 6 and the desulfurizer 7 that are thermally connected to each other with the heat insulating material 9 interposed therebetween are wrapped with an outer heat insulating material (heat insulating material) 10 so as to cover the outer periphery thereof. The outer heat insulating material 10 surrounds the casing 6, the desulfurizer 7 and the heat insulating material 9 so as to be thermally sealed from the outside, and these are fixed and integrated with each other. In addition, as the outer heat insulating material 10, the material and specification are not limited similarly to the said heat insulating material 9, A various thing can be used.

As described above, in the fuel cell module 1 of the present embodiment, the desulfurizer 7 is attached so as to be thermally connected to the upper surface 6 a of the housing 6. Therefore, instead of heating the desulfurizer 7 by the heat of the exhaust gas, as shown in FIG. 3, the heat generation of the cell stack 3 itself and the combustion of the combustion unit 4 that were conventionally only released from the housing 6 to the outside. Heat from the housing 6 is transferred from the housing 6 to the desulfurizer 7, and the desulfurizer 7 can be heated to 100 ° C or higher (preferably 150 ° C to 300 ° C). From the viewpoint of heating the desulfurizer 7, the cell stack 3 is preferably a solid oxide fuel cell or a molten carbonate fuel cell having a high operating temperature.

Therefore, for example, since it is not necessary to heat the desulfurizer 7 with the exhaust gas, it is possible to prevent the overall energy efficiency from being lowered due to a decrease in the exhaust gas temperature. That is, it is possible to suppress a decrease in energy efficiency due to heating of the desulfurizer 7. Further, since the desulfurizer 7 can be heated and maintained at a high temperature, a relatively inexpensive metal-based desulfurization catalyst that requires heating can be used as the desulfurization catalyst, and the zeolite desulfurization agent carrying metal fine particles is supported. It is not necessary to use a relatively expensive desulfurization catalyst represented by Therefore, according to the present embodiment, it is possible to realize cost reduction while maintaining energy efficiency.

Further, in this embodiment, the desulfurizer 7 can be integrated with the housing 6, and it is not necessary to arrange the desulfurizer 7 separately from the housing 6, so that the configuration can be made compact. Moreover, in this embodiment, the structure which directly heat-exchanges the desulfurizer 7 with waste gas is also unnecessary. In addition, since the desulfurizer 7 is not heated as much as the reformer 2, the desulfurization catalyst 7x is not limited to those that can be used in a temperature range very close to the reforming catalyst (for example, about 600 ° C.).

Moreover, in this embodiment, since the desulfurizer 7 is attached to the upper surface 6a of the housing 6 via the heat insulating material 9 as described above, the heat insulating material 9 connects the housing 6 to the desulfurizer 7. It becomes possible to control the temperature of the desulfurizer 7 by controlling the heat transfer.

In this embodiment, as described above, the casing 6 and the desulfurizer 7 are wrapped with the outer heat insulating material 10. Therefore, the desulfurizer is configured by transferring heat from the casing 6 to the desulfurizer 7 instead of the above-described effects, that is, heating the desulfurizer 7 with the heat of the exhaust gas, rather than the heat generated by the cell stack 3 or the combustion of the combustion unit 4. The effect of heating 7 can be effectively exhibited.

Further, in the present embodiment, as described above, the flow path 8 of the desulfurizer 7 is folded back, and heat exchange is possible between the inlet 8a side and the outlet 8b side of the flow path 8. Therefore, in the desulfurizer 7, the hydrogen-containing fuel that has flowed into the inlet portion 8a is heated with the hydrogen-containing fuel that flows out from the outlet portion 8b. As a result, for example, as illustrated in FIG. 3, the temperature distribution O1 of the desulfurizer 7 that has conventionally been low on the inlet 8a side of the flow path 8 and easily increased on the outlet 8b side is suitable for the desulfurization catalyst 7x. The temperature distribution O2 can be made uniform so as to be maintained within a range (for example, 150 ° C. to 300 ° C.).

In the fuel cell module 1 of the present embodiment, the cell stack 3, the combustion unit 4, the reformer 2, and the desulfurizer 7 are arranged in this order from the bottom to the top, and the desulfurizer 7 is heated. ing. Therefore, heat can be suitably transferred to the desulfurizer 7 using the property (convection) in which the heat is directed from the bottom to the top.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. The present invention is modified without departing from the scope described in the claims or applied to others. It may be.

For example, the arrangement position of the water vaporizer 5 is not limited to the above embodiment, and the water vaporizer 5 may be arranged at the bottom in the housing 6.

In the above embodiment, the desulfurizer 7 is attached to the upper surface 6 a of the housing 6. However, the desulfurizer 7 may be attached to the bottom surface or the side surface of the housing 6. It is only necessary to be attached so as to be connected. Further, the direction in which the desulfurizer 7 is arranged is horizontal in the above embodiment, but may be vertical, and as shown in FIG. 5 (a), the desulfurizer 7 of FIG. May be reversed.

Further, the form of the flow path 8 in the desulfurizer 7 is not limited to the above embodiment. For example, in the flow path 8 ′ illustrated in FIG. 5B, an inlet portion 8a ′ is provided substantially at the center of the side surface 7a in the desulfurizer 7, and an outlet portion 8b is provided above the side surface 7a so as to be close to the inlet portion 8a ′. 'Is provided. Such a flow path 8 extends straight from the inlet portion 8a to the vicinity of the side surface 7b in the pipe 7d, and then is folded back toward the side surface 7a so as to wrap around from above and below outside the pipe 7d. It extends toward.

Also in such a flow path 8 ′, the hydrogen-containing fuel in the pipe 7d on the inlet portion 8a side is heated by the hydrogen-containing fuel flowing out from the outlet portion 8b, that is, the hydrogen-containing fuel flowing through the desulfurizer 7 is Heat exchange is performed between the inlet 8a side and the outlet 8b side of the flow path 8 ′.

According to the present invention, it is possible to realize cost reduction while maintaining energy efficiency.

DESCRIPTION OF SYMBOLS 1 ... Fuel cell module, 2 ... Reformer, 3 ... Cell stack, 6 ... Case, 6a ... Upper surface (outer surface), 7 ... Desulfurizer, 8, 8 '... Flow path, 8a, 8a' ... Inlet part, 8b, 8b '... outlet, 9 ... heat insulating material, 10 ... outer heat insulating material (heat insulating material).

Claims

A reformer that generates reformed gas using hydrogen-containing fuel;
A cell stack for generating power using the reformed gas;
A housing that houses at least the reformer and the cell stack;
A desulfurizer that desulfurizes the hydrogen-containing fuel supplied to the reformer,
The desulfurizer is a fuel cell module attached so as to be thermally connected to an outer surface of the casing.
The fuel cell module according to claim 1, wherein the desulfurizer is attached to an outer surface of the casing via a heat insulating material.
The fuel cell module according to claim 1 or 2, wherein the casing and the desulfurizer are wrapped with a heat insulating material.
The desulfurizer has a flow path for circulating the hydrogen-containing fuel therein,
4. The flow path according to claim 1, wherein the flow path is folded back so that heat exchange can be performed between an inlet portion side through which the hydrogen-containing fuel flows and an outlet portion side through which the hydrogen-containing fuel flows out. Fuel cell module.