JP2010222208A - Reformer and fuel cell system using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reformer adapted so that the insulation sealing body of the heater is prevented from reaching a high temperature and to provide a fuel cell system using the same. <P>SOLUTION: What is provided is a reformer provided with at least a reaction tube 4 provided with an outer tube 11, an inner tube 8, and a catalyst layer, a fluid feed part 14a which feeds a fluid necessary for a reforming reaction, and a heater 18 windingly fixed to the outer tube 11 of the reaction tube 4, wherein the heater 18 is composed of an open-end metallic sheath and a heat-generating wire with a non-heat-generating wire connected thereto and an insulation material packed in the gap between the heat-generating wire and the metallic sheath both of which are encased in the metallic sheath having an opening at an end and an insulation sealing body 28 fixed in a manner that part of the non-heat-generating wire is exposed to the outside through a through-hole on the opening, and that part of the metallic sheath which locates near the insulation sealing body 28 of the heater 18 is fixed to the fluid supply part 14a in contact therewith through a heat conductor 20. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reformer in a fuel cell system.

  Conventionally, the reformer is provided with a heater for preheating the catalyst portion. And the example which raises the temperature of a catalyst part for a short time and improves the reaction efficiency of a catalyst part by energizing and heating a heater at the time of starting is disclosed (for example, refer to patent documents 1).

  Hereinafter, a conventional reformer having a general structure will be described with reference to the drawings.

  FIG. 3 is a partial cross-sectional view showing the overall configuration of a conventional reformer.

  As shown in FIG. 3, the reformer has a catalyst in a reaction tube 29 having a double tube structure with an outer tube 30 and an inner tube 31, and an annular space between the outer tube 30 and the inner tube 31. A filled catalyst layer 32 is provided. A heater 33 having a heating wire is spirally wound around the outer peripheral surface of the outer tube 30 to heat the catalyst layer 32. Further, the reaction tube 29 is provided with temperature detection ports 34a, 34b, 34c for attaching a temperature sensor made of, for example, a thermocouple or a thermistor for measuring the temperature of the catalyst layer 32.

And based on the temperature detected with the temperature sensor, the heating amount of the heater 33 is adjusted and controlled so that the temperature of the catalyst layer 32 becomes 180 degreeC-200 degreeC, for example.
JP 2003-192306 A

  However, in the above-described conventional configuration, the temperature of the outer tube 30 is transmitted to the heater 33 by heat conduction during the reforming reaction, so that there is a problem that the outer tube 30 cannot be used at a location where the temperature exceeds the heat resistance temperature of the heater 33. It was. For example, in a heater having an insulating sealing body, the heater becomes hot due to the heat transfer of the temperature of the outer tube, so that the insulating sealing body is thermally deteriorated and the insulation performance between the heating wire inside the heater and the metal sheath or the outside There is a problem that the reliability of the reformer is lowered. As a result, in order to maintain the insulation durability of the insulation sealing body of the heater, there has been a problem that the heater cannot be attached at a location where the temperature exceeds the heat resistant temperature in the reforming reaction.

  The present invention solves the above-described conventional problems, and a reformer capable of preventing the temperature of a heater, particularly an insulating sealing body, from being high, and mounting the heater at a high temperature, and the same It aims at providing the fuel cell system using this.

  In order to solve the above-described conventional problems, a reformer of the present invention includes a reaction tube including at least an outer tube, an inner tube, and a catalyst layer, a fluid supply unit that supplies a fluid necessary for the reforming reaction, and a reaction A heater wound around a tube and fixed in close contact with the heater. The heater has a heating wire having a non-heating wire connected to a terminal portion and an insulating material filled in a gap between the heating wire and the metal sheath at the end portion. An insulating sealing body that is housed in a metal sheath having an opening, and is attached to the opening so that a portion of the non-heating wire is exposed to the outside through the through hole. The metal sheath in the vicinity of the stationary body is configured to contact and be fixed to the fluid supply unit via a heat transfer body.

With this configuration, the temperature of the insulating sealing body of the heater can be prevented from becoming high. As a result, it is possible to realize a highly reliable reforming apparatus that can attach a heater to a high temperature location.

  The fuel cell system of the present invention includes at least the reformer and a fuel cell. As a result, it is possible to realize a highly reliable fuel cell system that operates the reforming reaction stably over a long period of time.

  The reforming apparatus of the present invention can prevent the temperature of the insulating sealing body of the heater from becoming high, and can attach the heater to a place where the temperature becomes high, which has been difficult to attach conventionally.

  A first invention includes a reaction tube including a catalyst layer filled in at least an outer tube, an inner tube, and an annular space therebetween, a fluid supply unit that supplies a fluid necessary for a reforming reaction, and an outer tube of the reaction tube A heater that is wound and fixed tightly around the outside of the heater, the heater having an end portion that includes a heating wire having a non-heating wire connected to a terminal portion, and an insulating material filled in a gap between the heating wire and the metal sheath. And an insulating sealing body attached to the opening so that a part of the non-heating wire is exposed to the outside through the through hole. The reforming device has a configuration in which a metal sheath in the vicinity of the sealing body is fixed in contact with the fluid supply unit via a heat transfer body.

  With this configuration, the temperature of the insulating sealing body of the heater can be prevented from becoming high. As a result, it is possible to realize a highly reliable reforming apparatus that attaches a heater at a high temperature location and operates the reforming reaction stably over a long period of time.

  In the second invention and the first invention, the fluid supply unit is a reformed water supply unit. Thereby, the temperature of the reforming water supplied to the reformer can be increased by the heat generated by the heat conduction from the heater. As a result, it is possible to increase the efficiency of the reformer by reducing the amount of heat supplied from the outside necessary for the reforming reaction.

  In a third aspect based on the first aspect, the fluid supply unit is a source gas supply unit. As a result, the temperature of the raw material gas supplied to the reformer can be increased by heat generated by heat conduction from the heater. As a result, it is possible to increase the efficiency of the reformer by reducing the amount of heat supplied from the outside necessary for the reforming reaction.

  A fourth invention is a fuel cell system comprising at least the reforming apparatus of any one of the first to third inventions and a fuel cell. Thereby, it is possible to realize a highly reliable fuel cell system capable of stably operating the reforming reaction for a long period of time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the same reference numerals are given to the same configurations as the conventional configurations described above, and the detailed description thereof will be omitted. The present invention is not limited to the embodiments.

(Embodiment 1)
Hereinafter, the reformer according to Embodiment 1 of the present invention will be described in detail.

  FIG. 1 is a partial cross-sectional view showing the overall configuration of the reforming apparatus according to Embodiment 1 of the present invention.

As shown in FIG. 1, the reformer includes a combustor 1, a reaction tube 4 having a double tube structure of at least an outer tube 11 and an inner tube 8, a fluid such as reforming water, raw material gas, and air. The fluid supply parts 14a and 14b to be supplied and the heater 18 wound in close contact with the outer tube 11 of the reaction tube 4 are configured at least.

  Here, the combustor 1 includes a city gas (or LPG) supplied from the gas valve 2, an off gas (unreacted hydrogen gas) discharged from the fuel cell, a fuel gas in which the city gas and the off gas are mixed, and a blower 3. The supplied combustion air is combusted, and high-temperature combustion gas is discharged into the reaction tube 4.

  The reaction tube 4 has a plurality of concentric tube shapes, and in order from the inside, the first tube 5 from which the combustion gas from the combustor 1 is released, the second tube 6, the inner tube 8, and the outer tube It consists of a tube 11. A combustion gas flow path 7 is formed by an annular space between the first cylinder 5 and the second cylinder 6. Further, an evaporation portion 9 is formed by an annular space between the second cylinder 6 and the inner tube 8, and the reforming catalyst layer 10 is provided in the evaporation portion 9. A catalyst layer such as a shift catalyst layer 12 and a selective oxidation catalyst layer 13 is provided in the annular space between the inner tube 8 and the outer tube 11.

  On the outer peripheral surface of the outer tube 11, fluid supply units 14 a and 14 b that are reforming water supply units, a temperature detection port 15, a selective oxidation air port 16, and a reformed gas pipe 17 are provided. Here, the fluid supply unit 14a supplies the reformed water necessary for the steam reforming reaction, the fluid supply unit 14b supplies the raw material gas, and the selective oxidation air port 16 performs the carbon monoxide selective oxidation reaction included in the reformed gas. Supply the necessary air. The temperature detection port 15 is provided with a temperature sensor such as a thermocouple or a thermistor, and detects the temperature of the catalyst layers such as the reforming catalyst layer 10, the shift catalyst layer 12, and the selective oxidation catalyst layer 13.

  Further, the heater 18 is tightly fixed to the outer tube 11 by being wound, for example, spirally from the outside. At this time, the vicinity of the end portion 19 of the heater that is not tightly fixed to the outer tube 11 is fixed in a state of being in contact with the fluid supply portion 14a to which the reforming water is supplied via the heat transfer body 20. As the heat transfer body 20, for example, a metal such as stainless steel or copper, carbon, or the like can be used.

  Below, the structure of the heater used for the reformer in Embodiment 1 of this invention is demonstrated in detail using drawing.

  FIG. 2 is a cross-sectional view of a heater used in the reforming apparatus according to Embodiment 1 of the present invention.

  As shown in FIG. 2, the heater 18 is first housed in the metal sheath 21 with the end portion 23 a of the heating wire 23 connected to the non-heating wire 22. At this time, the heat generating portion 25 is configured by filling the gap of the metal sheath 21 containing the heat generating wire 23 with an insulating material 24 such as magnesia. The insulating sealing body is inserted into the opening 26 at the end of the metal sheath 21 in a state where the non-heating line 22 protruding from the opening 26 at the end of the metal sheath 21 is inserted into the through hole 27 of the insulating sealing body 28. 28 is press-fitted and installed. At this time, a part of the non-heating line 22 is exposed to the outside from the insulating sealing body 28 and is connected to an external power source, a control circuit, or the like.

  With the above configuration, the heater 18 allows the degree of adhesion between the non-heat generating wire 22 and the through hole 27 when the insulating sealing body 28 is press-fitted and the opening 26 at the end of the metal sheath 21 and the insulating sealing body. The degree of contact with the metal sheath 21 ensures insulation and airtightness with the metal sheath 21.

  Below, operation | movement of the reformer provided with the heater 18 comprised as mentioned above is demonstrated.

First, when starting the reformer, each catalyst layer is heated together with high-temperature (for example, 1000 ° C.) combustion gas supplied from the combustor 1 by energizing the heater 18. When the temperature of the shift catalyst layer 12 or the selective oxidation catalyst layer 13 detected by the temperature sensor reaches, for example, 180 ° C. to 200 ° C., the heating amount of the heater 18 is adjusted to maintain the temperature of each catalyst layer. That is, the heating time of each catalyst layer is shortened by the heating of the heater 18.

  And if each catalyst layer heats up to the temperature required for steam reforming reaction, electricity supply to heater 18 will be stopped and heating will be stopped.

  Next, when the temperature is raised to a temperature necessary for the steam reforming reaction, reforming water necessary for the steam reforming reaction is supplied from the fluid supply unit 14a and a fluid such as a raw material gas is supplied to the evaporation unit 9 from the fluid supply unit 14b. The At this time, the fluid such as the raw material gas and the reformed water is, for example, heat transferred to the second cylinder 6 when the combustion gas combusted in the combustor 1 passes through the combustion gas flow path 7 on the inner wall surface of the evaporator 9. Thus, the raw material gas is heated or the reformed water is evaporated into steam. Then, the heated raw material gas and the fluid such as the evaporated reforming water are supplied to the reforming catalyst layer 10 to generate a hydrogen-containing gas by a steam reforming reaction with the reforming catalyst.

  Next, the generated hydrogen-containing gas is further passed through the shift catalyst layer 12 and the selective oxidation catalyst layer 13 to change the carbon monoxide generated in the reforming reaction into carbon dioxide by the aqueous shift reaction and the selective oxidation reaction. Let Thereby, the reformed gas in which carbon monoxide is reduced to about 50 ppm is supplied from the reformed gas pipe 17 to a power generation cell of a fuel cell (not shown).

  At this time, the outer tube 11 of the reaction tube 4 is heated by the passage of the combustion gas or the steam reforming reaction. In this case, the temperature of the outer tube 11 is higher than when the temperature is raised by the heater 18 at the start of operation. As a result, the heat of the outer tube 11 that has become high increases the temperature of the heater 18 itself by heat conduction. At this time, the heater 18 may be heated to a temperature higher than the heat resistance temperature (generally limited by the heat resistance temperature of the insulating sealing body).

  However, according to the present embodiment, the end portion 19 of the heater 18 is in close contact with and fixed to the fluid supply portion 14a that is the reforming water supply portion via the heat transfer body 20. Then, the heat transferred to the end 19 of the heater 18 is transferred by heat conduction to the fluid supply 14a that is the reforming water supply, so that the temperature of the end 19 of the heater 18 is lowered. As a result, the temperature of the opening 26 and the insulating sealing body 28 at the end of the metal sheath 21 at the end 19 of the heater 18 does not become high, so that the insulation durability is not impaired. Furthermore, the heater 18 can be attached to a location where the temperature is limited by the heat-resistant temperature of the insulating sealing body 28 of the heater 18 and which has been difficult to attach conventionally.

  As described above, according to the present embodiment, the heat at the end of the heater can be absorbed by the reforming water supplied to the fluid supply unit via the heat transfer body. Therefore, the insulation durability of the opening of the metal sheath at the end of the heater and the insulating sealing body does not deteriorate. As a result, it is possible to realize a highly reliable reforming apparatus and fuel cell system that can stably maintain the reforming reaction for a long period of time.

  Moreover, according to this Embodiment, the temperature of fluids, such as reforming water required for the steam reforming reaction which passes a fluid supply part, rises with the heat supplied via a heat exchanger from a heater. As a result, since the amount of heat supplied from the outside necessary for the steam reforming reaction can be reduced, a highly efficient reformer and fuel cell system can be realized.

  In the above embodiment, the example in which the end portion 19 of the heater 18 is fixed in contact with the fluid supply portion 14a that is the reforming water supply portion has been described, but the present invention is not limited thereto. For example, the end portion 19 of the heater 18 may be fixed in contact with the fluid supply portion 14b which is a source gas supply portion. As a result, the temperature of the source gas flowing through the source gas supply unit rises due to the heat supplied from the heater 18 via the heat transfer body. As a result, since the amount of heat supplied from the outside necessary for the steam reforming reaction can be reduced, a highly efficient reformer and fuel cell system can be realized.

  Furthermore, the fluid supply unit may be an air supply unit supplied from a selective oxidation air port. Thereby, the temperature of the air supplied to the selective oxidation catalyst increases. As a result, the temperature of the mixed gas of reformed gas and air that passes through the selective oxidation catalyst becomes high, so that the reaction efficiency of the selective oxidation catalyst is increased and a reformer and a fuel cell system with a high CO removal rate in the reformed gas are provided. realizable.

(Embodiment 2)
The fuel cell system according to Embodiment 2 of the present invention will be described below.

  The fuel cell system according to the present embodiment includes at least the reforming device according to the first embodiment and the fuel cell. The fuel cell generates power by a chemical reaction between the hydrogen-containing gas supplied from the reformer and air.

  According to the present embodiment, it is possible to realize a fuel cell system having high power generation efficiency while maintaining a reforming reaction stably over a long period of time by a reformer having high thermal efficiency.

  The present invention is useful in the technical field of reformers and fuel cell systems that require stable operation over a long period of time.

The fragmentary sectional view which shows the whole structure of the reformer in Embodiment 1 of this invention Sectional drawing of the heater used for the reformer in Embodiment 1 of this invention Partial sectional view showing the overall structure of a conventional reformer

DESCRIPTION OF SYMBOLS 1 Combustor 2 Gas valve 3 Blower 4,29 Reaction tube 5 1st cylinder 6 2nd cylinder 7 Combustion gas flow path 8,31 Inner tube 9 Evaporating part 10 Reforming catalyst layer 11,30 Outer tube 12 Metamorphic catalyst layer 13 Selection Oxidation catalyst layer 14a, 14b Fluid supply unit 15, 34a, 34b, 34c Temperature detection port 16 Selective oxidation air port 17 Reformed gas pipe 18, 33 Heater 19 End 20 Heat transfer body 21 Metal sheath 22 Non-heating line 23 Heating line 23a Terminal part 24 Insulating material 25 Heat generating part 26 Opening part 27 Through hole 28 Insulating sealing body 32 Catalyst layer

Claims (4)

A reaction tube including a catalyst layer filled in at least an outer tube, an inner tube, and an annular space therebetween;
A fluid supply unit for supplying a fluid necessary for the reforming reaction;
At least a heater wound around and fixed to the outside of the outer tube of the reaction tube, and the heater is disposed in a gap between a heating wire having a non-heating wire connected to a terminal portion and the heating wire and the metal sheath. Insulating seal that is mounted in a metal sheath having an opening at the end and filled with the filled insulating material so that a part of the non-heat generating wire is exposed to the outside through the through hole. A stop body,
A reformer in which the metal sheath in the vicinity of the insulating sealing body of the heater is fixed in contact with the fluid supply unit via a heat transfer body. The reforming apparatus according to claim 1, wherein the fluid supply unit is a reforming water supply unit. The reformer according to claim 1, wherein the fluid supply unit is a source gas supply unit. A fuel cell system comprising at least the reforming device according to any one of claims 1 to 3 and a fuel cell.