JP2009059657A - Indirect interior-reformed solid oxide fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an indirect interior-reformed SOFC of high thermal efficiency capable of suppressing thermal loss at heating of a desulfurizer in addition to a reformer. <P>SOLUTION: The indirect interior-reformed solid oxide fuel cell comprises a desulfurizer desulfurizing hydrocarbon based fuel, a reformer manufacturing reformed gas from the hydrocarbon based fuel desulfurized by the desulfurizer, a solid oxide fuel cell generating power using the reformed gas obtained by the reformer, and a case housing the solid oxide fuel cell. A part of the end face of the solid oxide fuel cell is to be a flame-forming part capable of forming flame by combusting anode offgas of the solid oxide fuel cell, the reformer is arranged at a position opposed to or at an upper part of the flame-forming part in the case, and the desulfurizer is arranged at a position opposed to the solid oxide fuel cell and not opposed to the flame-forming part, and that, at a position not at an upper part of the flame-forming part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an indirect internal reforming solid oxide fuel cell having a reformer in the vicinity of the fuel cell.

  Solid oxide fuel cells (hereinafter referred to as SOFC in some cases) are usually generated by reforming hydrocarbon fuels (reforming raw materials) such as kerosene and city gas in a reformer. Hydrogen-containing gas (reformed gas) is supplied. In the SOFC, the reformed gas and air are reacted electrochemically to generate electricity. The SOFC is usually operated at a high temperature of about 550 ° C to 1000 ° C.

  Various reactions such as steam reforming and partial oxidation reforming are used for the reforming. Both require a certain temperature. Therefore, an indirect internal reforming SOFC has been developed in which a reformer is installed in the vicinity of the SOFC (a position that receives heat radiation from the SOFC) and the reformer is heated by radiant heat from the SOFC. In particular, in an indirect internal reforming SOFC, combustible anode off-gas (gas discharged from the SOFC anode) is combusted in an indirect internal reforming SOFC container (module container), and this combustion heat is used as a heat source. As described above, the reformer is heated (see Patent Document 1).

In addition, sulfur contained in hydrocarbon fuel (reforming raw material) poisons the reforming catalyst and SOFC charged in the reformer, so sulfur in hydrocarbon fuel (reforming raw material) is removed. In many cases, a desulfurizer is used. The desulfurizing agent used in the desulfurizer has an appropriate operating temperature range, and the desulfurizing agent is heated to this operating temperature range. Patent Document 2 discloses that combustion exhaust gas from a burner of a fuel reformer is guided to a desulfurizer, thereby heating a catalyst in the desulfurizer.
JP 2004-319420 A Japanese Patent Laid-Open No. 5-3043

  When the desulfurizer is independently provided and the desulfurizer is heated by introducing the fuel exhaust gas from the combustion exhaust gas line to the desulfurizer as in Patent Document 2, the thermal efficiency of the entire apparatus is reduced due to heat radiation from the piping.

  An object of the present invention is to provide an indirect internal reforming SOFC that can suppress heat loss when heating a desulfurizer in addition to a reformer and has high thermal efficiency.

According to the present invention, a desulfurizer for desulfurizing hydrocarbon fuel,
A reformer that produces reformed gas from the hydrocarbon-based fuel desulfurized by the desulfurizer;
A solid oxide fuel cell that generates power using the reformed gas obtained by the reformer;
A housing for housing the solid oxide fuel cell,
A part of the end face of the solid oxide fuel cell is a flame forming part capable of forming a flame by burning the anode off gas of the solid oxide fuel cell,
The reformer is disposed in the casing at a position facing the flame forming portion or above the flame forming portion;
The desulfurizer is indirectly disposed at a position in the casing facing the solid oxide fuel cell, not facing the flame forming portion, and not above the flame forming portion. An internal reforming solid oxide fuel cell is provided.

  According to the present invention, an indirect internal reforming SOFC having high thermal efficiency can be provided that can suppress heat loss when heating a desulfurizer in addition to a reformer.

  Hereinafter, one embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited thereto.

  FIG. 1 schematically shows an embodiment of the indirect internal reforming SOFC of the present invention. (A) is a top sectional view, (b) is a front sectional view, and (c) is a side sectional view.

  The indirect internal reforming SOFC includes a desulfurizer 1, a reformer 2, a solid oxide fuel cell 3, and a casing that houses the desulfurizer, the reformer, and the solid oxide fuel cell (SOFC). (Hereinafter referred to as a module container in some cases). Further, the SOFC has a flame forming section 10 that can form a flame 5 by burning anode off gas (gas discharged from the anode of the SOFC). The upper part of the SOFC is the flame forming part.

  In the desulfurizer, hydrocarbon fuel is desulfurized.

  When the hydrocarbon fuel is a liquid fuel such as kerosene, the fuel vaporizer 6 can be provided upstream or downstream of the desulfurizer as needed for vaporization. The fuel vaporizer may be outside or inside the module container, but is preferably inside the module container from the viewpoint of thermal efficiency.

  The reformer produces reformed gas from the hydrocarbon fuel desulfurized by the desulfurizer. When steam is necessary to perform the reforming reaction, water or steam can be appropriately supplied to the reformer.

  In order to obtain water vapor, a water vaporizer that vaporizes water (liquid) can be used. The water vaporizer may be outside or inside the module container, but is preferably inside the module container from the viewpoint of thermal efficiency.

  The SOFC generates power using the reformed gas obtained in the reformer. In order to supply oxygen for the electrochemical reaction, an oxygen-containing gas such as air can be supplied to the indirect internal reforming SOFC.

  In the form shown in FIG. 1, liquid hydrocarbon fuel such as kerosene is used. Further, the SOFC has a cubic shape.

  The upper end surface of the SOFC (here, the upper surface of the SOFC) is the flame forming unit 10. The reformer 2 is disposed above the flame forming unit. A desulfurizer 1 is provided on the side of the SOFC. A fuel vaporizer 6 is provided between the desulfurizer and the reformer. The fuel vaporizer is connected downstream of the desulfurizer, the reformer is connected downstream of the fuel vaporizer, and the SOFC is further connected downstream of the reformer.

  Hydrocarbon fuel (liquid) is supplied to the desulfurizer 1. The desulfurized hydrocarbon fuel is supplied to the fuel vaporizer 6 where the hydrocarbon fuel is vaporized.

  The vaporized hydrocarbon fuel is supplied to the reformer and reformed. The reformed gas obtained from the reformer is supplied to SOFC 3 (particularly its anode). The anode outlet is opened at the upper surface of the SOFC, and the anode off-gas burns in this opening, and a flame 5 is formed. That is, the anode off gas is discharged from the upper surface of the SOFC and burned, and the combustion heat is effectively used in the reformer. Radiant heat generated by the SOFC is transmitted to the desulfurizer and the fuel vaporizer. Air is supplied to the cathode. Anode off-gas (especially combustible components contained therein) can be burned by cathode off-gas (gas discharged from the cathode). The combustion exhaust gas is discharged from a discharge port (not shown) provided in the module container.

  The reformer 2 is disposed at a position facing the flame forming unit 10 of the SOFC 3 and above the flame forming unit 10. A reformer can be arrange | positioned in the position facing a flame formation part. Thereby, the combustion heat generated in the flame 5 can be efficiently transmitted to the reformer. In order to directly transmit the radiant heat from the flame to the reformer, it is preferable not to place a shield between the combustion region and the reformer. It is preferable not to place a shield between the flame forming section (here, the upper surface of the SOFC) and the reformer. In other words, it is preferable that the SOFC flame forming section and the reformer face each other without sandwiching a shield. However, necessary piping and the like are appropriately arranged.

  The desulfurizer 1 is disposed on the side of the SOFC 3 in the module container 4. That is, the desulfurizer is disposed at a position facing the SOFC but not facing the flame forming section, and at a position (for example, side or below) not above the flame forming section. Thereby, the radiant heat from SOFC can be transmitted to a desulfurizer. It is preferable not to place a shield between the desulfurizer and the SOFC so that the radiant heat from the SOFC is directly transmitted to the desulfurizer.

  In this way, by providing a reformer above the flame formation part existing in the upper part of the SOFC and providing the desulfurizer on the side of the SOFC, the heat required for the reformer and the desulfurizer can be efficiently obtained from the SOFC. It becomes possible to supply to.

  Here, the reformer is disposed at a position facing the flame forming portion and above the flame forming portion. This form is particularly preferred from the viewpoint of reformer heating. However, this is not the case. For example, when the upper surface of the SOFC 3 is not a flame forming portion but one side surface is a flame forming portion, the reformer is positioned at a position facing the flame forming portion and not above the flame forming portion ( Side). In this case, the reformer can be heated by radiant heat from the flame. Alternatively, the reformer can be placed above the flame forming section, although it does not face the flame forming section. In this case, the reformer can be heated by convective heat transfer.

  By arranging the SOFC, anode off-gas combustion region, reformer, and desulfurizer as described above, the exhaust heat of SOFC can be used extremely effectively not only in the reformer but also in the desulfurizer. It becomes possible to improve the thermal efficiency of the indirect internal reforming SOFC.

  Each feed is appropriately preheated as necessary and then supplied to the indirect internal reforming SOFC.

  As the module container, an appropriate housing capable of accommodating at least SOFC can be used. As the material, for example, an appropriate material having resistance to the environment to be used, such as stainless steel, can be used. The module container is appropriately provided with a connection port for gas exchange and the like. The module container is preferably airtight so that the interior of the module container does not communicate with the outside (atmosphere). Appropriate shapes such as a rectangular parallelepiped shape and a cylindrical shape can be adopted as the outer shape of the module container.

  In the present invention, the reformer is disposed in the module container (housing). As shown in FIG. 1, in addition to the case where the reformer provided separately from the module container exists inside the module container, at least a part of the module container is formed by the reformer itself. This includes cases where That is, the reformer may be integrated with the module container. The same applies to the desulfurizer.

  In order to obtain a structure in which the reformer forms at least a part of the module container, for example, at least a part of the module container has a double-wall structure, and a space between the inner wall and the outer wall is formed. A reforming catalyst can be accommodated. Alternatively, the reaction vessel can be fixed to the wall of the module vessel by welding or the like, and the reforming catalyst can be accommodated inside the reaction vessel. This is preferable from the viewpoint of compactness.

  In order to obtain a structure in which the desulfurizer forms at least a part of the module container, for example, at least a part of the module container has a double wall structure and is desulfurized in a space between the inner wall and the outer wall. Agents can be accommodated. Alternatively, the reaction vessel can be fixed to the wall of the module vessel by welding or the like, and the desulfurization agent can be accommodated inside the reaction vessel. This is preferable from the viewpoint of compactness.

  In FIG. 1, it is shown as if the reformed gas is supplied to the SOFC from the side, but these do not accurately indicate the gas supply position. In short, the reformed gas may be supplied to the anode of the SOFC and air may be supplied to the cathode.

  In the embodiment shown in FIG. 1, one reformer and one desulfurizer are used, but the present invention is not limited to this. For example, two desulfurizers (connected in parallel) can be arranged on both sides of the SOFC.

[Hydrocarbon fuel]
As the hydrocarbon-based fuel, as a reformed gas raw material, a compound known from the field of SOFC, containing carbon and hydrogen (may contain other elements such as oxygen) or a mixture thereof, or a mixture thereof may be used as appropriate. And compounds having carbon and hydrogen in the molecule such as hydrocarbons and alcohols can be used. For example, hydrocarbon fuels such as methane, ethane, propane, butane, natural gas, LPG (liquefied petroleum gas), city gas, gasoline, naphtha, kerosene, light oil, etc., alcohols such as methanol and ethanol, ethers such as dimethyl ether, etc. is there.

  Of these, kerosene and LPG are preferred because they are readily available. Moreover, since it can be stored independently, it is useful in areas where city gas lines are not widespread. Furthermore, SOFC power generators using kerosene or LPG are useful as emergency power supplies. In particular, kerosene is preferable because it is easy to handle.

[Desulfurizer]
The desulfurizer can include a desulfurizing agent and a container that stores the desulfurizing agent.

  As the desulfurizing agent, a known desulfurizing agent that requires heating can be appropriately used.

  For example, a so-called warm adsorption desulfurization agent can be used. As the warm adsorption desulfurization agent, a transition metal desulfurization agent can be used.

  As the structure of the desulfurizer, a structure known as a desulfurizer can be adopted as appropriate. For example, the desulfurizer has a region for accommodating a heated desulfurizing agent in a sealable container, and has an inlet and an outlet for a fluid to be desulfurized It can be a structure.

  The material of the desulfurizer can be appropriately selected from materials known as desulfurizers in consideration of the resistance in the usage environment.

  The shape of the desulfurizer can be an appropriate shape such as a rectangular parallelepiped shape or a circular tube shape.

[Reformer]
The reformer produces a reformed gas containing hydrogen from a hydrocarbon fuel.

  The reformer can be provided with a known non-noble metal or noble metal reforming catalyst having generally known steam reforming ability, partial oxidation reforming ability, and the like.

  As the structure of the reformer, a structure known as a reformer can be appropriately adopted. For example, it is possible to have a structure having a region for accommodating the reforming catalyst in a sealable container and having an inlet for fluid necessary for reforming and an outlet for reforming gas.

  The material of the reformer can be appropriately selected and adopted from materials known as reformers in consideration of resistance in the use environment.

  The shape of the reformer can be an appropriate shape such as a rectangular parallelepiped or a circular tube.

  Supply hydrocarbon-based fuel (pre-vaporized if necessary), water vapor, and oxygen-containing gas such as air, if necessary, individually or appropriately mixed to the reformer (reforming catalyst layer) can do. The reformed gas is supplied to the anode of the SOFC.

[SOFC]
The reformed gas obtained from the reformer is supplied to the anode of the SOFC. On the other hand, an oxygen-containing gas such as air is supplied to the cathode of the SOFC. The SOFC generates heat with power generation, and the heat is radiated from the SOFC to the reformer and desulfurizer. Thus, the SOFC exhaust heat is utilized for the endothermic reaction of the reforming reaction and the adsorptive desulfurization reaction. Gas exchange and the like are appropriately performed using piping or the like.

  As the SOFC, a known SOFC capable of burning the anode off gas at the anode outlet can be appropriately selected and employed. In the SOFC, oxygen ion conductive ceramics or proton ion conductive ceramics are generally used as an electrolyte.

  The SOFC may be a single cell, but in practice, a bundle or stack in which a plurality of single cells are arranged is preferably used. In this case, one or a plurality of bundles or stacks may be used.

  The shape of the SOFC is not limited to the cubic stack, and an appropriate shape can be adopted.

[Other equipment]
Known components of the indirect internal reforming SOFC can be appropriately provided as necessary. Specific examples include a vaporizer for vaporizing liquid, a pump for pressurizing various fluids, a pressure increasing means such as a compressor and a blower, a valve for adjusting the flow rate of the fluid, or for blocking / switching the flow of the fluid. Such as flow control means, flow path blocking / switching means, heat exchanger for heat exchange / recovery, condenser for condensing gas, heating / heat-retaining means for externally heating various devices with steam, etc., hydrocarbon system These include fuel and combustible storage means, instrumentation air and electrical systems, control signal systems, control devices, and output and power electrical systems.

  The indirect internal reforming SOFC of the present invention can be used for, for example, a stationary or moving power generation system and a cogeneration system. The reformer of the present invention can be suitably used for such an indirect internal reforming SOFC.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows one form of the indirect internal reforming type solid oxide fuel cell of this invention, (a) is upper surface sectional drawing, (b) is front sectional drawing, (c) is side sectional drawing.

Explanation of symbols

1 Desulfurizer 2 Reformer 3 SOFC
4 Case (module container)
5 Flame 6 Fuel vaporizer 10 Flame formation part

Claims (1)

A desulfurizer for desulfurizing hydrocarbon fuel,
A reformer that produces reformed gas from the hydrocarbon-based fuel desulfurized by the desulfurizer;
A solid oxide fuel cell that generates power using the reformed gas obtained by the reformer;
A housing for housing the solid oxide fuel cell,
A part of the end face of the solid oxide fuel cell is a flame forming part capable of forming a flame by burning the anode off gas of the solid oxide fuel cell,
The reformer is disposed in the casing at a position facing the flame forming portion or above the flame forming portion;
The desulfurizer is indirectly disposed at a position in the casing facing the solid oxide fuel cell, not facing the flame forming portion, and not above the flame forming portion. Internal reforming type solid oxide fuel cell.

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