JP2003261302A - Hydrogen production apparatus and fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen production apparatus using a transforming apparatus capable of surely decreasing carbon monoxide in a reformed gas and a fuel cell system using the hydrogen production apparatus. <P>SOLUTION: The transforming apparatus is provided with a transforming part 6 connected to a reforming part 1 and having a transforming catalytic body 7 inside and a purification inlet heat recovering part 9 which is connected to the downstream side of the transforming part 6 and one end of which has a purification inlet water supply part 10 and another end of which is connected to the transforming part 6 and moreover, the transforming apparatus is provided with a transforming temperature detecting part 8 for detecting the temperature of the transforming part 6 and a control part 20 connected to the transforming temperature detecting part 8 and the purification inlet water supply part 10. Water is supplied from the purification inlet water supply part 10 and exchanges heat with the reformed gas to be supplied to the transforming part 6. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a hydrogen generator such as a solid polymer fuel cell using hydrogen as a fuel, and a fuel cell system using the hydrogen generator.

[0002]

2. Description of the Related Art A fuel cell cogeneration system, which has high power generation efficiency and high overall efficiency, has been attracting attention as a distributed power generation device that effectively uses energy.

Many of the fuel cells, for example, the phosphoric acid type fuel cell which has been put into practical use and the solid polymer type fuel cell which is being developed, generate electricity using hydrogen as a fuel. However, hydrogen has not been prepared as an infrastructure, so it must be generated at the system installation site.

A steam reforming method is one of the methods for producing hydrogen. Hydrocarbon-based materials such as natural gas, LPG, naphtha, gasoline, kerosene, and alcohol-based materials such as methanol are mixed with water, and a steam reforming reaction is carried out in a reforming section provided with a reforming catalyst to generate hydrogen. Is the way.

In this steam reforming reaction, carbon monoxide is produced as an auxiliary component. Since carbon monoxide poisons the fuel cell electrode catalyst, especially for polymer electrolyte fuel cells,
It is necessary to remove the carbon monoxide concentration in the reformed gas to 100 ppm or less, preferably 10 ppm or less.

Usually, a hydrogen generator is equipped with a shift conversion section having a shift conversion catalyst for reacting carbon monoxide and steam after the reforming section to remove carbon monoxide in the reformed gas, and the carbon monoxide in the air. A purifying unit having a purifying catalyst that causes a selective oxidation reaction with the oxygen in the reformed gas is provided to increase the carbon monoxide concentration in the reformed gas to 100
Reduce to below ppm.

[0007]

However, although the shift catalyst usually can reduce carbon monoxide by supplying more water, on the other hand, the shift catalyst is cooled by supplying water, so that the temperature of the shift catalyst is increased. When it decreased, carbon monoxide could not be decreased in some cases.

For example, when the temperature of the reformed gas to be supplied to the shift conversion section is low when water is supplied to the shift conversion section, the temperature of the shift conversion catalyst is lowered when water at about room temperature is supplied, so that the reformed gas is reduced. In some cases, the carbon monoxide concentration could not be reduced.

Further, Japanese Patent Application No. H10-255001 discloses a hydrogen generator which keeps the temperature of the shift conversion section constant by increasing or decreasing the amount of water supplied to the shift conversion section. However, in the method of increasing / decreasing the amount of supplied water so as to keep the temperature of the shift catalyst constant, the shift catalyst cannot supply the amount of water necessary for reducing carbon monoxide, and the concentration of carbon monoxide in the reformed gas is insufficient. In some cases, it was not reduced.

In view of the above problems, the present invention provides a hydrogen generator using a shift converter capable of reliably reducing carbon monoxide in a reformed gas, or a fuel cell system using the hydrogen generator. The purpose is to provide.

[0011]

According to a first aspect of the present invention (corresponding to claim 1), a first shift section connected downstream of a reforming section for reforming a raw material and having a first shift catalyst therein, A first heat recovery unit that is connected to the downstream of the first shift conversion unit, has a first water supply unit at one end, and has the other end connected to the upstream side of the first shift conversion catalyst of the first shift conversion unit; It is a hydrogen generator which has a transformation part provided with.

A second aspect of the present invention (corresponding to claim 2) is a first shift temperature detecting portion for detecting the temperature of the first shift portion, the first shift temperature detecting portion and the first water supply. And a control unit connected to the unit.

A third aspect of the present invention (corresponding to claim 3) has a second water supply section connected to the control section, and is arranged in a purifying section connected downstream of the first heat recovery section. A part of which is connected to the upstream side of the first shift conversion catalyst of the first shift conversion section,
It is a hydrogen generator of the 1st or 2nd of the present invention further provided with the 2nd heat recovery part.

A fourth aspect of the present invention (corresponding to claim 4) has a third water supply section connected to the control section, is disposed in the first shift conversion section, and is the first of the first shift conversion sections. The hydrogen generating apparatus according to any one of the first to third aspects of the present invention, further including a third heat recovery unit, a part of which is connected to an upstream side of the shift catalyst.

In a fifth aspect of the present invention (corresponding to claim 5), a second shift section having a second shift catalyst is connected downstream of the first heat recovery section, and the control section is connected to the second shift section. A second shift temperature detection unit connected to the control unit is installed at one end thereof, and a fourth water supply unit connected to the control unit is provided at one end of the second shift temperature detection unit. A first heat recovery section, which is connected to the upstream side of the first shift catalyst of the first shift section or upstream of the second shift catalyst of the second shift section,
4 is a hydrogen generator of the present invention.

According to a sixth aspect of the present invention (corresponding to claim 6), the first heat recovery section, the second heat recovery section, and the second heat recovery section are connected between the reforming section and the first shift conversion section. A 3 heat recovery part, or a part of the fourth heat recovery part is connected, and a mixing part for mixing the reformed gas and water is provided, and the fluid mixed in the mixing part is the first shift catalyst. The hydrogen generator of any one of the first to fifth aspects of the present invention, which is supplied to the upstream side.

A seventh aspect of the present invention (corresponding to claim 7) is the first aspect.
A fuel cell system comprising: the hydrogen generating device according to any one of the first to sixth aspects of the present invention; and a fuel cell that uses the gas emitted from the hydrogen generating device to generate electricity.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a configuration diagram of a hydrogen generator according to Embodiment 1 of the present invention. In the figure, a reforming unit 1, which is an example of the reforming unit of the present invention, includes a reforming catalyst 2, a raw material supply unit 3 that supplies a raw material to the reforming catalyst 2, and a reforming unit that supplies water to the reforming catalyst 2. A water supply unit 4 and a reforming heating unit 5 for heating the reforming unit 1 are provided. A metamorphic section 6 which is an example of the first metamorphic section of the present invention is connected downstream of the reforming section 1. The shift conversion section 6 contains a shift conversion catalyst body 7, which is an example of the first shift catalyst of the present invention for reducing carbon monoxide in the reformed gas supplied from the reforming section 1 by a shift reaction. In the present embodiment, as the shift catalyst body 7,
A metal oxide supporting Pt and then coating a cordierite honeycomb is used.

In the shift conversion section 6, a shift temperature detection section, which is an example of the first shift temperature detection section of the present invention for detecting the temperature of the reformed gas supplied from the reforming section 1 to the shift section 6, is provided. 8
Are inserted on the upstream side of the shift catalyst body 7. In addition, a purification inlet heat recovery unit 9 that is an example of the first heat recovery unit of the present invention, in which the pipe is formed in a coil shape, is installed downstream of the shift conversion unit 6. The first of the present invention is provided at one end of the purification inlet heat recovery section 9.
A purification inlet water supply unit 10, which is an example of a water supply unit, is connected. The other end of the purification inlet heat recovery unit 9 is connected to the upstream side of the shift conversion catalyst body 7 of the shift conversion unit 6.

Downstream of the purification inlet heat recovery section 9, a purification section 11 which is an example of the purification section of the present invention is connected.
The purifying catalyst 12 is housed in. Purification catalyst 12
For this, a mixture of Pt and Ru supported on a metal oxide and then coated on a cordierite honeycomb is used.

An air pump 13 is installed on the upstream side of the purification section 11. In addition, the purification catalyst 12
A purification temperature detection unit 14 for detecting the temperature of the reformed gas supplied from the shift conversion unit 6 to the purification unit 11 is installed upstream of. A purification cooling fan 15 for cooling the reformed gas supplied from the shift conversion unit 6 to the purification unit 11 from the outside of the purification unit 11 is installed upstream of the purification catalyst body 12.

The shift temperature detecting section 8, the purification inlet water supply section 10, the air pump 13, and the purification cooling fan 15 are connected to a control section 20 which is an example of the control section of the present invention.

As described above, the hydrogen generator shown in FIG.
The shift device, which is an example of the shift unit of the present invention, including the shift unit 6, the purification inlet heat recovery unit 9, and the control device 20 is a component.

Next, the operation of the hydrogen generator having the above structure will be described with reference to an example in which methane gas is used as a raw material.

First, water is supplied from the reforming water supply unit 4, a part of methane gas as a raw material gas is supplied to the reforming heating unit 5, and the reforming unit 1 is heated to generate steam. And
When the reforming catalyst 2 rises to a predetermined temperature, methane gas as a raw material gas is supplied from the raw material supply unit 3 to the reforming unit 1 to cause the reforming reaction in the reforming catalyst 2. Next, the reformed gas generated by the reforming reaction is sent to the shift converter 6.

The reformed gas introduced into the shift conversion section 6 causes a shift reaction in the shift conversion catalyst body 7 together with the water supplied from the purification inlet water supply section 10, and carbon monoxide contained in the reformed gas is reduced. It At this time, the water supplied from the purification inlet water supply unit 10 exchanges heat with the reformed gas discharged from the shift conversion unit 6 in the purification inlet heat recovery unit 9, so that the shift conversion catalyst body 7 is heated. Is supplied upstream.

Then, the shift temperature detector 8 detects the temperature upstream of the shift catalyst body 7 (hereinafter referred to as the temperature of the shift catalyst body 7), and when the temperature of the shift catalyst body 7 falls below a predetermined temperature, The control unit 20 controls the purification inlet water supply unit 10
A command is issued to the purification inlet water supply unit 10 to limit the amount of water supplied from the purification inlet water supply unit 10. At this time, the purification inlet water supply unit 10
Reduces the amount of water supplied to the shift conversion unit 6 via the purification inlet heat recovery unit 9 and reduces the amount of water passing through the purification inlet heat recovery unit 9 at the same time. Therefore, the temperature rise range of water becomes large. In this way, it is possible to prevent the temperature in the transformation section 6 from being lowered more than necessary.

On the contrary, when the temperature in the shift conversion section 6 rises more than necessary, the control section 20 issues a command to increase the amount of water supplied from the purification inlet water supply section 10. Then, the purification inlet water supply unit 10 operates to open the valve, and increases the amount of water supplied to the shift conversion unit 6. As a result, the amount of water passing through the purification inlet heat recovery section 9 increases, the temperature rise width of the water decreases, the temperature inside the shift conversion section 6 rises more than necessary, and the performance of the shift conversion catalyst body 7 decreases. Can be prevented.

Here, when the amount of water supplied to the shift conversion section 6 is large, the steam dew point of the reformed gas becomes high. For example, when a polymer electrolyte fuel cell is provided downstream of the hydrogen generator of the present embodiment, water condenses in a reformed gas passage (not shown) in the fuel cell The water content may need to be set in consideration of the operating temperature of the fuel cell as well because the water may be clogged and the characteristics may deteriorate.

Next, the reformed gas discharged from the shift conversion section 6 is purified by the purification section 1.
1 is supplied. Then, oxygen contained in the air supplied from the air pump and carbon monoxide contained in the reformed gas are
A selective oxidation reaction occurs on the purification catalyst body 12, and carbon monoxide contained in the reformed gas is reduced to about 100 ppm. At this time, if the temperature of the purification catalyst body 12 rises too much, the performance of the purification catalyst body 12 deteriorates. Therefore, when the purification temperature detection unit 14 detects a temperature equal to or higher than a predetermined temperature, the control unit 20 causes the purification cooling fan to operate. By issuing a command to operate 15 and cooling the periphery of the purification unit 11, it is possible to prevent the temperature of the purification catalyst 12 from rising more than necessary. In this way, the purification unit cooling fan 15 is ON-OFF controlled by the temperature detected by the purification temperature detection unit 14, and the purification catalyst body 1
It is possible to maintain the temperature of 2 within a certain range and stabilize the carbon monoxide removal action in the purification unit 11.

(Second Embodiment) FIG. 2 shows a hydrogen generator according to a second embodiment of the present invention.

Although the hydrogen generator shown in the first embodiment is configured to recover the heat of the reformed gas after passing through the shift conversion section, in the present embodiment, the reaction of the purification catalyst body 12 of the purification section 11 is performed. Take a configuration to recover heat. However, the other points are the same as those in the first embodiment, and the same components are designated by the same reference numerals and the description thereof will be omitted. In the following description, points different from the first embodiment will be mainly described.

In the hydrogen generator of this embodiment,
A purification unit heat recovery unit 21, which is an example of the second heat recovery unit of the present invention and covers the outside of the purification unit 11, is installed so as to surround the purification catalyst body 12. A part of the purification part heat recovery part 21 is provided with a purification part water supply part 22 which is an example of a second water supply part of the present invention for supplying water to the shift conversion part 6. In addition, another part of the purification unit water supply unit 22 is the shift unit 6
Is connected to the upstream side of the shift conversion catalyst body 7.

As described above, the water supplied to the shift converter 6 is
It has two systems of water supplied from the purification inlet water supply unit 10 through the purification inlet heat recovery unit 9 after heat exchange, and water supplied from the purification unit water supply unit 22 through the purification unit heat recovery unit 21 after heat exchange. ing.

Further, the control unit 30 in the present embodiment
Is connected to the purification unit water supply unit 22 in addition to the shift temperature detection unit 8, the purification inlet water supply unit 10, the air pump 13, the purification unit cooling fan 15.

As described above, the hydrogen generator shown in FIG. 2 has as its constituent elements a shift device including the shift unit 6, the purification inlet heat recovery unit 9, and the control unit 30.

According to the hydrogen generator having such a configuration, it is generated on the purification catalyst 12 when oxygen in the air supplied by the air pump 13 reacts with carbon monoxide in the reformed gas. By collecting the heat from the water supplied from the purifying unit water supply unit 22 and passing through the purifying unit heat recovery unit 21, it is possible to supply the temperature-increased water to the shift conversion unit 6. Therefore, without lowering the temperature of the shift catalyst body 7,
Compared with the case of the first embodiment, a larger amount of water is supplied to the metamorphic section 6.
Can be supplied to. Here, the purification unit water supply unit 22
The increase or decrease in the amount of water supplied from the control unit 30 is determined by the temperature detected by the purification temperature detection unit 14.

Further, by passing water through the heat recovery section 21 of the purification section, the purification catalyst body 12 can be effectively cooled. Since the oxidation reaction of carbon monoxide in the purification catalyst 12 is an exothermic reaction, when the purification catalyst 12 is cooled to some extent and the reaction heat is taken away, the oxidation reaction is more likely to proceed (that is, the catalytic activity should be improved. However, carbon monoxide can be further reduced. However, if the temperature of the purification catalyst body 12 (that is, the temperature detected by the purification temperature detection unit 14) decreases too much, the catalyst activity decreases, so at this time, the control unit 30 controls the purification unit water supply unit 22 to Limit or stop the amount of water supplied. On the contrary, when the temperature of the purification catalyst body 12 rises too much, the control unit 30
Increases the amount of water supplied from the purification unit water supply unit 22 or operates the purification unit cooling fan 15 to cool the purification unit 11.

In the above description, the purification unit water supply unit 2
The increase / decrease in the water supply amount from 2 is determined by the temperature detected by the purification temperature detecting unit 14, but may be determined based on the temperature detected by the shift temperature detecting unit 8.

Further, in the above description, one purification section 11
Was described as being connected to the downstream side of the metamorphic section 6,
The purifying unit 11 is constituted by a plurality of stages, each stage holds a corresponding purifying catalyst, and means for recovering heat of the purifying catalyst of each stage or heat of the reformed gas passing through each stage is provided. The same effect can be obtained even when water is supplied.

Further, in the hydrogen generator of the present embodiment, the purifying section 11 surrounds the purifying catalyst body 12.
A purification unit heat recovery unit 21 that covers the outside of the
However, the purification unit heat recovery unit 21 is
It may be installed inside.

(Embodiment 3) FIG. 3 is a configuration diagram of a hydrogen generator in Embodiment 3 of the present invention. The differences from the first embodiment will be mainly described.

In addition to the features of the first embodiment, the present embodiment is characterized in that the heat of reaction due to the shift reaction of the shift catalyst body 7 is recovered with water and then supplied to the shift section 6. .

In the hydrogen generator of this structure, the shift heat recovery unit 31, which is an example of the third heat recovery unit of the present invention for recovering the heat of the shift catalyst 7, surrounds the shift catalyst 7. Thus, it is installed so as to cover the outside of the metamorphic section 6.
And a part of shift conversion part heat recovery part 31 is connected to the shift conversion part water supply part 32 which is an example of the 3rd water supply part of this invention, and another part of the shift conversion part heat recovery part 31 is a shift conversion part. 6 is connected to the upstream side of the shift conversion catalyst body 7. Further, the control unit 40 includes the shift temperature detection unit 8, the air pump 13, and the purification unit cooling fan 1.
5. In addition to the purification temperature detection unit 14, the shift unit water supply unit 32
It is connected to the.

As described above, the hydrogen generator shown in FIG. 3 has as its constituent elements a shift device including the shift unit 6, the purification inlet heat recovery unit 9, the shift unit heat recovery unit 31, and the control unit 40.

When water supplied from the shift conversion unit water supply unit 32 is passed through the shift conversion unit heat recovery unit 31 to the hydrogen generator having such a structure, the water is heated by the reaction in the shift conversion catalyst body 7. Is collected and supplied to the shift converter 6. At this time, the control unit 40 issues a command to the shift converter water supply unit 32 and the purification inlet water supply unit 10 so that the temperature on the upstream side of the shift catalyst body 7 detected by the shift temperature detection unit 8 becomes a predetermined temperature. The amount of water supplied from the shift conversion unit water supply unit 32 and the purification inlet water supply unit 10 to the shift conversion unit 6 is controlled.

At this time, the shift catalyst body 7 advances a shift reaction by carbon monoxide in the reformed gas and steam, but since this reaction is an exothermic reaction, the shift catalyst body 7 is cooled to some extent and the reaction heat is generated. When it is deprived, the shift reaction is more likely to proceed (that is, the catalytic activity can be improved), and carbon monoxide can be further reduced. As a result, a large amount of water can be supplied to the shift conversion section 6 while maintaining the temperature required to maintain the catalytic activity of the shift conversion catalyst body 7, and the carbon monoxide concentration can be further reliably reduced. .

In the hydrogen generator of the present embodiment, the shift conversion section heat recovery unit 31 for recovering the heat generated by the shift conversion catalyst body 7 covers the outside of the shift conversion section 6 so as to surround the shift conversion catalyst body 7. However, the shift conversion unit recovery unit 31 may be installed inside the shift conversion unit 6.

Further, in addition to the present embodiment, by using it in combination with that described in the second embodiment, there is an effect that carbon monoxide can be further reliably reduced.

(Embodiment 4) FIG. 4 is a configuration diagram of a hydrogen generator according to Embodiment 4 of the present invention. The description will be omitted while omitting the same points as in the first embodiment.

The feature of this embodiment is that the transformation unit is
That is, the heat of the reformed gas flowing between the stages is recovered by water and can be supplied to one shift section. In FIG. 4, a shift upper catalyst body 52, which is an example of the first shift catalyst of the present invention, is installed in the shift upper stage portion 51, which is an example of the first shift converter of the present invention.
On the upstream side of the above, a metamorphic upper temperature detecting unit 53, which is an example of the first metamorphic temperature detecting unit of the present invention, is installed. The shift upper temperature detector 53 detects the temperature of the reformed gas supplied from the reformer 1 to the shift upper portion 51 on the upstream side of the shift upper catalyst body 52.

The first part of the present invention is provided downstream of the metamorphic upper part 51.
An inter-transformation unit heat recovery unit 61 that is an example of a heat recovery unit is installed, and one end of the inter-transformation unit heat recovery unit 61 is connected to an inter-transformation unit water supply unit 62 that is an example of the first water supply unit of the present invention. The other end of the inter-transformation part heat recovery part 61 is connected to the upstream side of the shift upper catalyst part 52 of the shift upper part 51. Further, downstream of the inter-transformation part heat recovery part 61 is connected to a lower transformation part 54 which is an example of the second transformation part of the present invention. The metamorphic lower-stage catalyst body 55 is held in the metamorphic lower-stage catalyst body 55, and the metamorphic lower-stage temperature detecting portion 56 is inserted on the upstream side of the metamorphic lower-stage catalyst body 55. Transformation lower-stage cooling fan 5 for cooling the catalyst body 55
8 is provided outside the metamorphic lower step portion 54. Here, as the shift upper catalyst body 52 and the shift lower catalyst body 55, those obtained by supporting Pt on the metal oxide and then coating it on the cordierite honeycomb are used. Further, downstream of the shift lower catalyst body 55, a shift lowermost temperature detection unit 57 for detecting the temperature of the reformed gas in the downstream of the shift lower catalyst body 55.
Is provided.

A purification inlet heat recovery section 9 which is an example of the fourth heat recovery section of the present invention is installed downstream of the shift conversion lower section 54, and the purification inlet heat recovery section 9 is the same as in the first embodiment. Similarly to the above, one end thereof is connected to the purification inlet water supply unit 10, and the other end is connected to the upstream side of the shift upper-stage catalyst body 52 of the shift upper-stage unit 51.

Further, the control unit 70 includes the shift upper temperature detector 53, the inter-transformer water supply unit 62, and the shift lower temperature detector 5.
6, the transformation lower stage cooling fan 58, the transformation lowermost temperature detection unit 57, the purification inlet water supply unit 10, the air pump 13, the purification unit cooling fan 15, and the purification temperature detection unit 14.

As described above, in the hydrogen generator shown in FIG. 4, the shift upper section 51, the inter-transformer heat recovery section 61, and the shift lower section 5 are provided.
4, the conversion device including the purification inlet heat recovery unit 9 and the control unit 70 is a component.

In the hydrogen generator having such a structure,
Metamorphic upper temperature detecting section 53 and metamorphic lower temperature detecting section 5
The control unit 70 controls the amount of water supplied from the inter-transformation unit water supply unit 62 and the purification inlet water supply unit 10 so that the temperature detected in 6 reaches a predetermined temperature. Here, when the temperature of both the shift conversion upper catalyst body 52 and the shift lower catalyst body 55 is higher than a predetermined temperature, the shift water between the shift portions 62,
Alternatively, the amount of water supplied from the purification inlet water supply unit 10 is increased. However, when the shift upper catalyst body 52 is in a predetermined temperature range but the shift lower catalyst body 55 is higher than the predetermined temperature, the shift lower cooling fan 58 is operated to start the shift lower stage 54 from the outside. The catalyst body 55 is cooled.

By doing so, the heat recovery section 6 between the shift conversion sections
1 and the purification inlet heat recovery unit 9 can supply the heat recovered water from the reformed gas, so that the shift upper-stage catalyst body 52 and the shift lower-stage catalyst body 55 can be maintained at necessary temperatures,
More water can be supplied to the metamorphic upper stage part 51. Therefore, carbon monoxide can be reduced more reliably than in the case of the first embodiment.

Therefore, according to the hydrogen generator having such a structure, the carbon monoxide can be reduced more stably and surely, unlikely to be influenced by the operating conditions.

In the present embodiment, the other end of the purification inlet heat recovery section 9 is described as being connected to the upper conversion section 51, but the other end of the purification inlet heat recovery section 9 is connected to the lower conversion step. The portion 54 may be connected to the upstream side of the shift lower catalyst body 55. In that case, the temperature control of the shift conversion lower catalyst body 55 can be performed independently of the temperature control of the shift conversion upper catalyst body 52.

In addition to the present embodiment, by using it in combination with that described in the second embodiment or the third embodiment, there is an effect that the carbon monoxide can be further surely reduced.

In the present embodiment, the shift upper catalyst body 52 and the shift lower catalyst body 55 are explained as using the same catalyst species, but the shift upper catalyst body 52 and the shift lower catalyst body 55 are different. It may be a catalytic species.

Further, in addition to the present embodiment, by using in combination with the ones described in the second and third embodiments, there is a further effect.

(Embodiment 5) As shown in FIG. 5, between the reforming section 1 and the shift converting sections 6 and 51, the reformed gas from the reforming section in the first to the fourth embodiments and By providing the mixing section 80, which is an example of the mixing section of the present invention, which mixes the water that passes through the heat recovery section and is supplied to the shift conversion section, carbon monoxide can be further reliably reduced.

FIG. 5 is a diagram showing a cross section of the mixing section 80 provided between the reforming section 1 and the transformation section 6 (or the transformation upper stage section 51) in the first to fourth embodiments.

As shown in FIG. 5, the mixing section 80 has a cavity 85 therein, a part of the cavity 85 is connected to the reforming section connecting pipe 83, and another part is connected to the water pipe 84. Has been done. Here, the water pipe 84 is the other end of the purification inlet water recovery part 9 in the first embodiment, another part of the purification part water supply part 22 in the second embodiment, and the shift conversion part heat recovery part in the third embodiment. It corresponds to another part of 31 or the other end of the inter-transformation part heat recovery part 61 in the fourth embodiment. Then, the cavity 85 is filled with a plurality of spheres 81. Sphere 8
Alumina (diameter about 3 mm) is used as 1.
In addition, a support net 82 is installed in the lower part of the cavity 85, the connecting part of the reforming part connecting pipe 83, and the connecting part 84 of the water pipe,
The sphere 81 does not leak out. Further, the cavity 85 is connected to the metamorphic portion 6 and the metamorphic upper stage portion 51 via a support net 82 as shown in FIG.

Since alumina is a porous material and has a large specific surface area, the mixing of water (steam) with the reformed gas is promoted and the contact probability of water and carbon monoxide can be increased. By supplying the mixed fluid to the upstream side of the shift catalyst bodies 7, 51 from the portion 80, the shift reaction in the shift catalyst bodies 7, 51, 55 is promoted.

In the present embodiment, an example of using alumina as the sphere 81 has been shown, but if it is a porous material such as silica or activated carbon, the same effect as described above can be obtained. Embodiment 6) FIG. 6 shows a configuration of a fuel cell system using the hydrogen generator 91 described in Embodiments 1 to 5.

In FIG. 6, the hydrogen generator 91 is connected to the source gas pipe 98, the water pipe 99, and the anode exhaust gas connecting pipe 104 on the input side, and the hydrogen supply pipe 100 on the output side. An anode inlet 102 of the fuel cell 92 is connected to the hydrogen pipe 100. Further, the anode outlet 94 of the fuel cell 92 is connected to the anode exhaust gas connecting pipe 104.

Then, the cathode inlet 10 of the fuel cell 92
3 to the air supply device 93 via the air supply pipe 101.
Are connected. An air exhaust pipe 105 is connected to the cathode outlet 95 of the fuel cell 92. The heat exchanger 9 is connected to the fuel cell 92 via a cooling water line 97.
6 is connected.

According to such a fuel cell system, when the raw material gas and water are supplied to the hydrogen generator 91, hydrogen is generated and the generated hydrogen is supplied to the anode inlet 102 of the fuel cell 92. On the other hand, air is supplied from the air supply device 93 to the cathode inlet 103 of the fuel cell 92. Then, the fuel cell 92 reacts the supplied hydrogen with oxygen contained in the air to generate electricity and heat. The generated heat is taken out of the fuel cell system via the heat exchanger 96.

At this time, the hydrogen remaining without contributing to the power generation reaction is supplied to the reforming heating section 5 of the hydrogen generator 91 through the anode exhaust gas connecting pipe 104. On the other hand, the remaining air, which does not contribute to the power generation reaction, is discharged to the outside of the fuel cell system via the air discharge pipe 105.

According to the fuel cell system configured and operated as described above, carbon monoxide contained in the hydrogen gas supplied from the hydrogen generator 91 is surely reduced. Even when a type fuel cell is used, stable operation can be maintained, and the maintenance cost of the fuel cell system can be reduced.

Example 1 Using the hydrogen generator having the structure of the first embodiment, hydrogen was generated from methane gas.

Methane gas as a hydrocarbon component, which is a raw material, was supplied from the raw material supply section 3 to the reforming section 1 from the reforming water supply section 4 with 2.5 mol of water per 1 mol of methane gas. .

At this time, the amount of methane gas supplied to the reforming section 1 was 5.4 L / min, and the temperature of the reforming catalyst 2 was about 700 ° C.
The reforming heating unit 5 controlled the heating amount so that the steam reforming reaction proceeded. Although detailed description is omitted, since the reformed gas at a temperature of about 700 ° C. after the reaction in the reforming catalyst 2 is configured to preheat the raw material and water to be supplied to the reforming section, the reforming section 1 The temperature of the reformed gas at the outlet of was about 450 to 500 ° C. Then, by adjusting the amount of water from the purification inlet water supply unit 10, the temperature detected by the shift temperature detection unit 8 was maintained at 350 ° C. Further, the amount of air from the air pump 13 was supplied so that the ratio of oxygen to be introduced and carbon monoxide in the reformed gas was about 2.

As a result, the amount of water to the metamorphic section 6 is steam /
A carbon molar ratio of 3.5 or more could be supplied. The carbon monoxide concentration at the outlet of the purification unit 11 was stable at 10 ppm.

Example 2 Using the hydrogen generator having the configuration of the second embodiment, hydrogen was generated from methane gas.

As a result, the temperature of the purification catalyst body 12 rises by about 100 ° C. from the temperature detected immediately after the purification inlet heat recovery section 9 due to the reaction heat of reaction of carbon monoxide and oxygen on the purification catalyst body 12. Was there. Further, when about 3 g / min of water was supplied from the purification unit water supply unit 22, all the water could be evaporated in the purification unit heat recovery unit 21, and could be supplied to the shift conversion unit 6 as steam. . Therefore, it was possible to supply a larger amount of water than in the case of Example 1 without lowering the temperature of the shift conversion catalyst body 7. As a result, it was possible to more reliably reduce carbon monoxide by the shift catalyst 7, and the carbon monoxide concentration at the outlet of the purification unit 11 was stable at 10 ppm.

(Example 3) Hydrogen was generated from methane gas using the hydrogen generator having the configuration of the fourth embodiment.

By increasing or decreasing the amount of water from the purification inlet water supply unit 9, the temperature detected by the shift upper temperature detecting unit 53 is set to 3
Hold at 50 ° C. In the steady state, the transformation upper stage 5
When the inlet of No. 1 was kept at 350 ° C., the outlet of the metamorphic upper stage section 51 became about 400 ° C. due to the heat generated by the metamorphic reaction. Therefore, the inter-transformation section water supply section 62 to the inter-transformation section heat recovery section 61
The amount of water supplied to was adjusted so that the temperature detected by the shift lower temperature detector 56 was maintained at 300 ° C. As a result, about 3 g / min of water could be evaporated and supplied.

Further, the transformation lower cooling fan 58 is turned ON-O.
By the FF control, the temperature detected by the transformation lowest temperature detecting unit 57 was maintained at about 250 ° C.

In order to surely reduce the carbon monoxide concentration in the shift converter, it is desirable to keep the temperature of the shift catalyst body low. However, since the reaction rate also decreases at low temperatures, there is an optimum value for the shift catalyst temperature. In the present embodiment, when the temperature detected by the shift bottom temperature detecting unit 57 is lower than 240 ° C., the carbon monoxide concentration tends to increase. Therefore, regarding the lower shift conversion section 54, the upstream temperature of the lower shift catalytic converter 55 is set to 300 ° C. depending on the amount of water supplied to the inter-transformation heat recovery section 61, and the lower shift cooling fan 5
By maintaining the temperature downstream of the shift conversion lower stage catalyst body 55 at 250 ° C. by the method No. 8, carbon monoxide was reliably reduced.
In addition, depending on the case, the conversion lowest temperature detection part 58 may be omitted.

In the above description of the embodiments, the shift temperature detecting portions 8, 53, 56 are the shift catalyst bodies 7,
Although it has been described that the temperature of the upstream side of 52, 55 is detected, the temperature of the shift catalyst bodies 7, 52, 55 themselves may be directly detected, and in that case, the same effect as above can be obtained.

Further, the purification temperature detecting section 14 is the purification catalyst body 1.
Although it has been described that the temperature of the upstream side of 2 is detected, the temperature of the purification catalyst 12 itself may be directly detected.

Further, in the above description, the purification cooling fan 15
Has been described as having a configuration in which the purification unit 11 is cooled from the outside, but it may be configured to cool the purification catalyst body 12.

In the above description, as the shift catalyst 7, the one in which Pt is supported on the metal oxide and then coated on the cordierite honeycomb is used, but other noble metal catalysts or Cu—Zn catalysts are used. , Fe-
The same effect can be obtained by using a Cr-based shift catalyst.

Further, in the above description, the purification catalyst body 12 was described as one in which Pt and Ru were mixed and supported on the metal oxide and then coated on the cordierite honeycomb, but Pt, Ru, A noble metal such as Rh may be used alone, or a noble metal prepared by mixing and alloying may be used, and in that case, the same effect is obtained.

Further, the temperatures set in the shift catalyst bodies 7, 51, 55 and the purification catalyst body 12 may differ from those in the examples depending on various apparatus configurations and operation parameters such as catalyst species in the above-described embodiment. However, even in that case, the above-mentioned effects are not changed.

The amount of water supplied to the shift converters 6 and 51 may be different from that of the embodiment depending on various apparatus configurations and operating parameters such as catalyst species in the above embodiment. The effect of is the same.

Further, in the above description, the control method of the purifying section cooling fan 15 is explained as ON-OFF control, but the present invention is not limited to this, for example, proportional control is used to change the air flow rate to control the temperature. The same effect can be obtained by controlling. Further, for example, the load signal of the fuel cell may be fetched as a feedforward element to perform ON-OFF or proportional control. Alternatively, the purification cooling fan 15 may be omitted depending on conditions such as the catalyst type, the set temperature, and the water supply amount.

Further, in the above description, the control device 2
Although 0, 30, 40, and 70 are supposed to control the hydrogen generator, they may be integrated with the controller of the fuel cell system.

Further, in the above description of the embodiment, it is assumed that there is the shift temperature detecting section 8 and the control section 20, 30, 40, or 70, but these elements are not provided,
For example, the amount of water supplied from the purification inlet water supply unit 10 may be set to an optimum value in advance according to the device configuration and the catalyst type. Alternatively, a valve (not shown) in the purification inlet water supply unit 10 may be configured to be adjustable according to external conditions such as the water temperature, the outside air temperature, and the operating state of the fuel cell connected to the hydrogen generator. .

In the above description, an example in which methane gas is used as a raw material has been described. However, as a raw material, a hydrocarbon-based or methanol-based alcoholic raw material such as natural gas, LPG, naphtha, gasoline, or kerosene. May be used.

[0095]

According to the present invention, it is possible to provide a hydrogen generator capable of reliably reducing carbon monoxide in the reformed gas, or a fuel cell system using the hydrogen generator.

Further, when the first shift temperature detecting section and the control section are provided, carbon monoxide can be reduced more reliably.

Further, when the second water supply section and the second heat recovery section are provided, carbon monoxide can be reduced more reliably.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a hydrogen generator using a shift converter according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a hydrogen generator using a shift converter according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a hydrogen generator using a shift converter according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a hydrogen generator using a shift converter according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view of a mixing unit used in the hydrogen generator using the shift converter according to the first to fourth embodiments of the present invention.

FIG. 6 is a configuration diagram of a fuel cell system using a hydrogen generator using the shift converter in the first to fifth embodiments of the present invention.

[Explanation of symbols]

1 reformer 6 metamorphosis department 7 Metamorphic catalyst 8 Metamorphic temperature detector 9 Purification inlet heat recovery section 10 Purification inlet water supply section 11 Purification Department 12 Purification catalyst 13 Air pump 14 Purification temperature detector 15 Purification cooling fan 20 Control unit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyoshi Taguchi             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Hidenobu Wakita             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 4G040 EA03 EA06 EB31 EB32 EB43                       EB44                 5H026 AA06                 5H027 AA06 BA17 KK42

Claims (7)

[Claims] 1. A first shift section connected downstream of a reforming section for reforming a raw material and having a first shift conversion catalyst therein, and connected downstream of the first shift section with a first water at one end thereof. A hydrogen generator having a shift section having a supply section and a first heat recovery section having the other end connected to the upstream side of the first shift catalyst of the first shift section. 2. A first shift temperature detecting section for detecting the temperature of the first shift section, and a control section connected to the first shift temperature detecting section and the first water supply section. Item 2. The hydrogen generator according to Item 1. 3. A first shift conversion catalyst of the first shift conversion unit, which has a second water supply unit connected to the control unit and is arranged in a purification unit connected downstream of the first heat recovery unit. The hydrogen generator according to claim 1 or 2, further comprising a second heat recovery part, a part of which is connected to the upstream side. 4. A third water supply unit connected to the control unit, arranged in the first shift conversion unit, and partially connected upstream of the first shift catalyst in the first shift unit. The hydrogen generator according to claim 1, further comprising a third heat recovery unit. 5. A second shift conversion unit having a second shift catalyst is connected downstream of the first heat recovery unit, and a second shift temperature detection unit connected to the control unit is installed in the second shift unit. Has a fourth water supply unit connected to the control unit at one end thereof, is installed downstream of the second shift conversion unit, and has the other end on the upstream side of the first shift catalyst of the first shift unit, The hydrogen generator according to claim 1, further comprising a fourth heat recovery unit connected to the upstream side of the second shift conversion catalyst of the second shift conversion unit. 6. The first heat recovery section, the second heat recovery section, the third heat recovery section, or the fourth heat recovery section, which is connected between the reforming section and the first shift conversion section. A mixing part for mixing the reformed gas and water is provided, a part of which is connected, and the fluid mixed in the mixing part is supplied to the upstream side of the first shift catalyst. The hydrogen generator according to any one of 1. 7. A fuel cell system comprising: the hydrogen generator according to any one of claims 1 to 6; and a fuel cell that uses a gas emitted from the hydrogen generator to generate electric power.