JP2002211903A - Fuel reforming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel reforming apparatus capable of transferring the heat generated by the partial oxidation reaction efficiently to the steam reforming reaction part and having excellent durability and energy efficiency in an auto thermal reforming (ATR) type reforming apparatus. SOLUTION: A gaseous material containing a hydrocarbon, steam and air is introduced into a reactor through a gaseous feed material introducing passage and the reformed gas is discharged from a reformed gas discharge passage to flow in opposition to the gaseous feed material introduction passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to autothermal reforming (autothermal reforming: A) for producing hydrogen from hydrocarbon fuel.
The present invention relates to an improved technology of a TR) type fuel reformer.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an autothermal reforming type (autothermal type) reforming apparatus in which a steam reforming reaction is promoted by utilizing heat generated in a partial oxidation reaction. This type of reformer is intended to improve the thermal efficiency by causing a partial oxidation reaction, which is an exothermic reaction, and a steam reforming reaction, which is an endothermic reaction, to be performed in the same reactor (Japanese Patent Application Laid-Open No. Hei 7 (1994)). -335238, JP-A-2000-203802
Reference).

[0003]

However, in practice,
Since the reaction rate of the partial oxidation reaction is much faster than the reaction rate of the steam reforming reaction, when the raw material gas (hydrocarbon, steam, air) is introduced into the reactor of the same flow type, the partial oxidation occurs upstream of the reactor. The reaction is completed, and the steam reforming reaction occurring downstream cannot sufficiently utilize the heat generated by the partial oxidation reaction.

On the other hand, in order to raise the temperature of the downstream portion of the reactor, there is also a means of increasing the rate of the autothermal reforming reaction. In this case, however, the temperature of the upstream portion becomes unnecessarily high.
There has been a problem in that the durability of the catalyst is reduced and the energy efficiency (reformed gas generation efficiency) of the reformer is reduced.
The present invention has been made in view of the above problems, and can efficiently transmit heat generated in a partial oxidation reaction to a steam reforming reaction section, and has excellent durability and energy efficiency of a catalyst. It is an object of the present invention to provide an improved fuel reformer.

[0005]

According to the first aspect of the present invention, a raw material gas containing hydrocarbon, water vapor and air is introduced into a reactor filled with a catalyst, and hydrogen and carbon monoxide are mainly contained. In a fuel reforming apparatus that generates a reformed gas, the reactor has a gas flow path in which flows are opposed to each other, and a turn-back section that turns the flow from one gas flow path to the other gas flow path, And that the source gas flows in from the source gas introduction path which is one gas flow path, and the generated reformed gas flows out from the reformed gas discharge path which is the other gas flow path. Features.

According to a second aspect of the present invention, in the first aspect of the invention, at least one of air, hydrocarbon, and water vapor is supplied to the folded portion from another gas supply path different from the source gas introduction path. It is characterized by doing. According to a third aspect of the present invention, in the first or second aspect of the present invention, an ignition device is provided near the folded portion.

According to a fourth aspect of the present invention, in the second or third aspect, the gas supply path exchanges heat with the reformed gas discharge path. The invention according to claim 5 is the invention according to claim 4, wherein the gas flow in the gas supply path is opposed to the gas flow in the reformed gas discharge path.

According to a sixth aspect of the present invention, in the invention according to any one of the first to third aspects, the raw material gas introduction path and the reformed gas discharge path are alternately laminated, and one of these is provided. An open end is connected to a vacant space constituting the folded portion. In the invention according to claim 7, in the invention according to claim 4 or claim 5, the source gas introduction path, the reformed gas discharge path, and the gas supply path are stacked, and one open end thereof is It is characterized in that it is connected to a vacant room constituting the folded portion.

The invention according to claim 8 is the invention according to claim 7, wherein the reactor is formed by sequentially stacking a raw material gas introduction path, a reformed gas discharge path, a gas supply path, and a reformed gas discharge path.
It is characterized by forming one unit and stacking the units. The invention according to claim 9 is the invention according to any one of claims 1 to 4,
The reactor is constituted by a double tube having an outer tube having an empty space on one end side of the folded portion, and an inner tube disposed inside the outer tube and connected to the empty space. The flow in the gas flow path formed in the inner pipe is opposed to the flow in the gas flow path formed between the outer pipe and the inner pipe.

A tenth aspect of the present invention is the invention according to any one of the first to fourth aspects, wherein the reactor has an outer tube having an empty chamber on one end side that forms the folded portion; A plurality of inner pipes arranged inside the outer pipe and connected to the empty chamber, wherein a flow in a gas flow path formed in each inner pipe is an outer pipe and each inner pipe. It is characterized by being opposed to the flow in the gas flow path formed between them.

An eleventh aspect of the present invention is the invention according to the tenth aspect, wherein a part of the inner pipe constitutes the gas supply pipe. The invention according to claim 12 is
In the invention according to any one of the first to eleventh aspects, the volume of the source gas introduction path is smaller than the volume of the reformed gas discharge path.

According to a thirteenth aspect of the present invention, in the invention according to any one of the first to twelfth aspects, the catalyst-filled inlet end of the raw material gas introduction passage has a reformed gas discharge passage. The catalyst is disposed so as to be located closer to the turn-back portion than the end of the catalyst filled therein.

[0013]

According to the first aspect of the present invention, the reaction speed is high, and the heat generated by the partial oxidation reaction, which is an exothermic reaction occurring mainly in the upstream portion of the gas flow in the reactor, is transferred to the downstream portion. The energy efficiency (reformed gas generation efficiency) of the apparatus can be improved because the energy can be efficiently transmitted to the section, the reaction rate is low, and the reaction can be used in the steam reforming reaction, which is an endothermic reaction. For this reason, it is possible to prevent the temperature of the upstream portion from becoming unnecessarily high, and to improve the durability of the catalyst.

According to the second aspect of the present invention, by supplying air (oxygen) from the gas supply path to the turn-back portion,
Since the partial oxidation reaction can be performed not only in the upstream part of the reactor but also in the vicinity of the turning part on the downstream side, the temperature distribution in the reactor can be made uniform. Also, by adjusting the ratio of air (oxygen), hydrocarbons, and water vapor in the gas in the reformed gas discharge passage, the temperature distribution in the reactor is made more uniform,
The reformed gas generation efficiency (energy efficiency) can be improved.

According to the third aspect of the present invention, for example, the hydrocarbon supplied to the folded portion can be ignited at the time of startup to cause a combustion reaction or a non-catalytic partial oxidation reaction. Therefore, not only the heating by the partial oxidation reaction in the upstream portion of the source gas introduction path, but also the inside of the device can be heated from the turn-back portion side, and the startup time of the device can be reduced.

According to the fourth aspect of the present invention, the heat generated by the partial oxidation reaction in the raw material gas introduction passage can be efficiently used in the steam reforming reaction in the reformed gas discharge passage, and the residual heat or the turnback portion The heat generated by the partial oxidation reaction in the reformed gas discharge path caused by the supply of air to the gas supply path can heat the gas in the gas supply path and supply it to the turn-back section. Temperature can be prevented, and the energy efficiency of the device can be maintained.

According to the fifth aspect of the present invention, in the reformed gas discharge path, a partial oxidation reaction occurs near the turning portion due to the supply of air to the turning portion. Since the gas flow in the gas supply path and the gas flow in the reformed gas discharge path are opposed to each other, the gas in the gas supply path is heated closer to the turn-back portion, so that the heating is not wasted. In addition, a high-temperature gas (air or the like) can be supplied to the folded portion.

According to the sixth aspect of the present invention, heat can be efficiently transferred in the heat exchange section between the source gas introduction path and the reformed gas discharge path, so that the apparatus is energy efficient even if the apparatus is downsized. Can be. In addition, as the number of stacked layers increases, the heat generating portion in the reactor can be dispersed, and the temperature distribution in the reactor can be made more uniform.

According to the seventh aspect of the present invention, heat transfer in the heat exchange section between the raw material gas introduction path and the reformed gas discharge path is efficiently performed, and the heat transfer between the gas supply path and the reformed gas discharge path is performed. Since heat transfer can also be performed efficiently, the energy efficiency of the device can be improved. According to the invention according to claim 8, the upper and lower sides of the inlet side catalyst where the partial oxidation reaction which is mainly an exothermic reaction is performed are sandwiched by the outlet side catalyst where the steam reforming reaction which is mainly an endothermic reaction is performed. Therefore, heat balance can be performed efficiently. Further, the unitization facilitates handling when manufacturing a reactor or the like.

According to the ninth aspect of the invention, for example, the heat generated by the partial oxidation reaction occurring in the inner tube can be efficiently transmitted to the steam reforming reaction section occurring between the outer tube and the inner tube. In this case, when the gas supply path is provided, an opening may be provided in a portion of the outer tube facing the folded portion, and the gas supply path may be connected to the opening.

According to the tenth aspect, the heat generated by the partial oxidation reaction occurring in the inner tube is efficiently transmitted to the steam reforming reaction section while being dispersed in the reactor (in the outer tube). Can be. According to the invention according to claim 11, heat is exchanged between the inner pipe through which the gas to be supplied to the turn-back portion flows and the partial oxidation reaction portion, thereby heating the gas and supplying the heated gas to prevent a temperature decrease. Thus, the energy efficiency of the device can be improved.

According to the twelfth aspect of the invention, the volume of the raw material gas introduction passage is made smaller than the volume of the reformed gas discharge passage, and the gas flow rates in the upstream part and the downstream part of the reactor are changed. In addition, the balance of heat balance (balance between heat generation and heat absorption) in consideration of the difference between the reaction rates of the partial oxidation reaction and the steam reforming reaction can be taken, so that the energy efficiency of the apparatus can be further improved.

According to the thirteenth aspect of the present invention, the heat generated by the partial oxidation reaction that occurs in the upstream portion of the inlet-side catalyst is wasted by distributing the inlet-side catalyst closer to the folded portion than the outlet-side catalyst. Therefore, the energy can be transmitted to the outlet side catalyst, and the energy efficiency of the apparatus can be further improved.

[0024]

Embodiments of the present invention will be described below. FIG. 1 shows a first embodiment of a fuel reforming apparatus according to the present invention. As shown in FIG.
The reactor 10 has a double tube structure and is formed by forming a raw gas inlet 1 and a reformed gas outlet 7 in a reactor 10 filled with a catalyst.

The reactor 10 has an outer tube 4 having one end communicating with the reformed gas outlet 7 and a folded portion 5 at the other end, and an inner tube 4 disposed inside the outer tube 4 and having one end connected to the raw material gas inlet 1. And an inner tube 2 whose other end communicates with the folded portion 5. An air supply port 7 is provided in a portion of the outer tube 4 facing the folded portion 5, and an air supply path (not shown) is provided.
Connected to.

The turning portion 5 turns the gas flowing in the inner tube 2 and guides the gas between the outer tube 4 and the inner tube 2.
The inside of the inner tube 2 and the space between the outer tube 4 and the inner tube 2 are filled with an inlet-side catalyst 3 and an outlet-side catalyst 6, respectively, to promote a reforming reaction (partial oxidation reaction, steam reforming reaction). Let it. Here, the inlet-side catalyst 3 and the outlet-side catalyst 6 may be any as long as they promote the reforming reaction.
There are copper catalysts, nickel catalysts, palladium catalysts, platinum catalysts, and rhodium catalysts.

Next, the operation of the fuel reformer having the above configuration will be described. A raw material gas containing hydrocarbons, water (steam) and air (or oxygen) prepared in an evaporator (not shown) and a mixer (not shown) is supplied to the raw material gas inlet 1.
Is introduced into the reactor 10. The introduced raw material gas is guided to the inner pipe 2 (raw material gas introduction path), and the inlet-side catalyst 3
Is partially reformed. In the inlet-side catalyst 3, a partial oxidation reaction having a high reaction rate is mainly performed. The partial oxidation reaction is an exothermic reaction, and the generated heat is transferred to the outlet catalyst 6 filled between the outer pipe 4 and the inner pipe 2 (reformed gas discharge passage) through the pipe wall of the inner pipe 2. You.

The raw material gas partially reformed by the inlet-side catalyst 3 is supplied to the outlet-side catalyst 6 through the turnback section 5. In the outlet side catalyst 6, the steam reforming reaction, which is an endothermic reaction having a slow reaction rate, mainly proceeds by the heat supplied through the inner wall of the inner pipe 2. Then, all hydrocarbons in the raw material gas are reformed by the outlet side catalyst 6 and discharged from the reformed gas outlet 7.

As described above, by constructing the reactor so that the reformed gas is discharged through the flow path (flow) opposite to the flow path in which the introduced raw material gas flows, the heat generated in the partial oxidation reaction section is generated. Can be efficiently transmitted to the steam reforming reaction section, and the energy efficiency of the apparatus can be improved. Also,
As shown in the figure, the volume of the raw material gas introduction path where the partial oxidation reaction with a high reaction rate occurs is made smaller than the volume of the reformed gas discharge path where the steam reforming reaction with a low reaction rate occurs. Since the flow rate of the gas can be set to a flow rate corresponding to the reaction rate, heat generation (partial oxidation reaction) and endothermic reaction (steam reforming reaction) can be balanced to further improve the energy efficiency of the apparatus.

Here, by supplying air from the air supply port 7 to the turn-back section 5, the raw material gas partially reformed through the inlet-side catalyst 3 and the supplied air are mixed. To the outlet side catalyst 6. As a result, the partial oxidation reaction can be performed not only on the upstream side of the inlet side catalyst 3 but also on the upstream side of the outlet side catalyst 6, and as shown in FIG. Can be.

In this embodiment, the air supply port 7 is provided to supply the air (oxygen) to the folded portion 5. However, in the embodiment shown in FIG. A gas supply port 7 'for supplying at least one of air, hydrocarbon, and water vapor instead of the air supply port 7,
An ignition plug 8 is provided in the folded portion 5. According to this, the ratio of the air, hydrocarbon, and steam of the gas in the reactor can be adjusted optimally, so that the temperature distribution in the reactor can be made more uniform, and the efficiency of the reforming reaction can be improved. In addition, since the combustion reaction and the non-catalytic partial oxidation reaction can be caused by igniting the hydrocarbon supplied to the folded portion, the start-up time of the device can be reduced.

Next, a third embodiment of the fuel reformer according to the present invention will be described. As shown in FIG. 4, this embodiment is a stacked fuel reformer. The reactor 20 includes a gas flow path formed by laminating a source gas introduction path 12, a reformed gas discharge path 14, and an air supply path 19;
And a turn-back portion 15 for turning the gas flowing through the flow path back to the reformed gas discharge path 14.

The source gas introduction path 12 has one end communicating with the source gas introduction port 11 and the other end communicating with the turn-back portion 15.
The raw material gas introduced from the raw material gas inlet 11 is supplied to the reactor 2
Guide to 0. The reformed gas discharge passage 14 has one end connected to the reformed gas outlet 17 and the other end connected to the turn-back portion 15, and discharges the reformed gas generated in the reactor 20.

One end of the air supply path 19 is the air inlet 1.
8, the other end side communicates with the folded portion 15, and supplies the air introduced from the air inlet 18 to the folded portion 15. In the raw material gas introduction path 12 and the reformed gas discharge path 14,
The inlet side catalyst 13 and the outlet side catalyst 16 are filled, respectively, to promote the reforming reaction. In this embodiment, also, the volume of the raw material gas introduction path 12 is
, The inlet-side catalyst 13 and the outlet-side catalyst 16
Are the same as those in the first and second embodiments.

As in the first embodiment, a source gas containing hydrocarbons, water vapor, and air (or oxygen) is introduced into the reactor 20 through the source gas inlet 11. The introduced gas is led to the raw material gas introduction path 12, and is partially reformed by the inlet-side catalyst 13. At (upstream of) the inlet-side catalyst 13, a partial oxidation reaction having a high reaction rate mainly occurs, and the generated heat is transferred to the reformed gas discharge passage 1 adjacent to the raw material gas introduction passage 12.
4 and the upstream portion of the air supply path 19.

The gas (partially reformed raw material gas) that has passed through the inlet-side catalyst 13 is sent to the turn-back section 15 and mixed with the air supplied from the air supply path 19 to the reformed gas discharge path 14. Sent. On the upstream side of the outlet-side catalyst 16 filled in the reformed gas discharge passage 14, a partial oxidation reaction, which is an exothermic reaction, is performed by the air supplied to the turnback portion 15. The heat generated here is transferred to the adjacent source gas introduction path 12.
And transmitted to the downstream portion of the air supply path 19.

The heat transferred to the downstream portion of the raw material gas introduction path 12 is used for the steam reforming reaction occurring here.
The generated heat can be used efficiently. Also, the outlet side catalyst 1
6, a steam reforming reaction occurs due to heat generated by the partial oxidation reaction at the upstream side of the outlet catalyst and heat transferred from the raw material gas introduction passage 12, and all hydrocarbons in the raw material gas are reformed. And is discharged from the reformed gas outlet 17.

Thus, the heat generated in the partial oxidation reaction can be efficiently used in the steam reforming reaction, and the air supplied to the folded portion 15 can be heated, so that the temperature in the folded portion 15 can be prevented from lowering. Here, in the present embodiment, as shown in FIG.
6 is unevenly distributed on the folded portion 15 side,
The temperature rapidly increased by the partial oxidation reaction in the upstream portion of the inlet-side catalyst 13 can be transmitted to the downstream portion and the outlet-side catalyst 16 without waste.

As described above, in the present embodiment, in each of the inlet-side catalyst 13 and the outlet-side catalyst 16, a partial oxidation reaction occurs on the upstream side with respect to the gas flow, and a steam reforming reaction occurs on the downstream side. In addition, heat generated in the partial oxidation reaction can be efficiently used in the steam reforming reaction. The source gas introduction path 12, the reformed gas discharge path 14, the air supply path 19, and the reformed gas discharge path 14 may be stacked in this order to form a unit, and the units may be stacked. With this configuration, the inlet-side catalyst portion, which is a partial oxidation reaction that is mainly an exothermic reaction, is reliably sandwiched by the outlet-side catalyst portion that is mainly a steam reforming reaction, which is an endothermic reaction. The balance can be efficiently performed, and the energy efficiency of the device can be improved.

In the embodiment shown in FIG. 5 (fourth embodiment), the folded portion 1
5, a gas supply path 19 ′ for supplying at least one of air, hydrocarbon, and water vapor was provided. Thus, as in the second embodiment, the temperature distribution in the reactor can be made uniform, the reforming reaction can be made more efficient, and the startup time of the apparatus can be reduced.

Next, a fifth embodiment of the fuel reformer according to the present invention will be described. As shown in FIG. 6, the present embodiment is a tube type heat exchange type fuel reformer. The reactor 30
One end communicates with the reformed gas outlet 27, and the other end includes an outer tube 24 having a folded portion 25. Inside the outer tube 24, a raw material gas introduction tube 22 and an air introduction tube 29 are included.

The source gas introduction pipe 22 has one end connected to the source gas inlet 21 and the other end connected to the turn-back portion, and guides the source gas introduced from the source gas inlet 21 into the reactor 30. One end of the air introduction pipe 29 is the air introduction port 21.
The other end communicates with the folded portion 25 to supply the air introduced from the air inlet 21 to the folded portion 25.

The turn-back section 25 turns the gas flowing through the raw material gas introduction pipe 22 to form an outer tube 24 and the raw material introduction pipe 2.
2 leads to a reformed gas discharge path formed by Also, as in the other embodiments, the raw material gas introduction pipe 22 is filled with an inlet side catalyst 23, and the space between the outer pipe 24 and the raw material gas introduction pipe 22 is filled with an outlet side catalyst 26. ing.

Also in this embodiment, the inlet side catalyst 23 is unevenly distributed on the side of the folded portion 25 with respect to the outlet side catalyst 26, and the volume of the raw material gas introducing pipe 22 is smaller than that of the outer pipe 24 by the raw material. It is smaller than the volume between the gas introduction pipe 22. As in the other embodiments, a source gas containing hydrocarbons, water vapor, and air (or oxygen) is introduced (supplied) into the reactor 30 from the source gas inlet 21. The introduced gas is led to the raw material gas introduction pipe 22 and is supplied to the inlet side catalyst 23.
Is partially reformed.

At the inlet side catalyst 23 (upstream side), a partial oxidation reaction having a high reaction rate mainly occurs, and the generated heat is transferred to the outlet side catalyst filled between the outer tube 24 and the raw material gas introduction tube 22. 26 (downstream) and air introduction pipe 29 (upstream)
Is transmitted to The raw material gas that has passed through the inlet-side catalyst 23 (partially reformed) is sent to the turn-back section 25 and mixed with the air supplied from the air introduction pipe 29 to form the outlet-side catalyst
Sent to.

In the upstream part of the outlet side catalyst 26, a partial oxidation reaction is performed by the air supplied in the turn-back part 25. The heat generated by this partial oxidation reaction is transmitted to the downstream portions of the source gas introduction pipe 22 and the air introduction pipe 29. In the downstream part of the outlet side catalyst 26, a steam reforming reaction occurs by heat transmitted from the upstream part and the raw material gas introduction pipe 22,
All hydrocarbons in the gas are reformed and discharged from the reformed gas outlet 27.

As described above, the heat generated in the partial oxidation reaction can be efficiently used in the steam reforming reaction, and the air supplied to the folded portion 25 can be heated, so that the temperature in the folded portion 25 can be prevented from lowering. Further, in the embodiment shown in FIG. 7 (sixth embodiment), instead of the air introduction pipe 29, a gas introduction pipe 29 'for supplying at least one of air, hydrocarbon, and steam to the folded portion 25 is provided. The spark plug 8 was provided in the folded portion 15.

As a result, as in the second and fourth embodiments, the temperature distribution in the reactor can be made uniform, the reforming reaction can be made more efficient, and the start-up time of the apparatus can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing a fuel reforming apparatus according to the present invention (first embodiment).

FIG. 2 is a diagram showing a relationship between a position in a reactor and a catalyst temperature according to the present invention.

FIG. 3 is a view showing a fuel reforming apparatus according to a second embodiment of the present invention.

FIG. 4 is a view showing a fuel reforming apparatus according to a third embodiment of the present invention.

FIG. 5 is a view showing a fuel reforming apparatus according to a fourth embodiment of the present invention.

FIG. 6 is a view showing a fuel reforming apparatus according to a fifth embodiment of the present invention.

FIG. 7 is a view showing a fuel reforming apparatus according to a sixth embodiment of the present invention.

[Explanation of symbols]

 1, 11, 21 ... Source gas inlet 2 ... Inner tube 3, 13, 23 ... Inlet side catalyst 4, 24 ... Outer tube 5, 15, 25 ... Turnback part 6, 16, 26 ... Outlet side catalyst 7, 17, 27 ... Reformed gas outlet 8 ... Ignition plug 10, 20, 30 ... Reactor 12 ... Source gas introduction path 14 ... Reformed gas discharge path 19 ... Air introduction path 19 '... Gas introduction path 22 ... Source gas introduction pipe 29 ... Air inlet pipe 29 '… Gas inlet pipe

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Kazuhiko Ishiwatari Nissan Motor Co., Ltd., 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture (72) Inventor Hiroshi Komatsu 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor F Terms (reference) 4G040 EA03 EA06 EA07 EB12 EB44 EB46 4G140 EA03 EA06 EA07 EB12 EB44 EB46

Claims (13)

[Claims] 1. A fuel reformer for introducing a raw material gas containing hydrocarbons, steam and air into a reactor filled with a catalyst to produce a reformed gas containing hydrogen and carbon monoxide as main components. The reactor is configured to include a gas flow path in which the flows are opposed to each other, and a turn-back portion that turns the flow from one gas flow path and guides the flow to the other gas flow path. Wherein the reformed gas flows in from a source gas introduction path, and the generated reformed gas flows out from a reformed gas discharge path, which is the other gas flow path. 2. The fuel according to claim 1, wherein at least one of air, hydrocarbon, and water vapor is supplied to the return portion from another gas supply passage different from the raw material gas introduction passage. Reformer. 3. The fuel reformer according to claim 1, wherein an ignition device is provided near the turn-back portion. 4. The fuel reformer according to claim 2, wherein the gas supply path exchanges heat with the reformed gas discharge path. 5. The fuel reformer according to claim 4, wherein a gas flow in the gas supply path is opposed to a gas flow in the reformed gas discharge path. 6. A method according to claim 1, wherein said source gas introduction passage and said reformed gas discharge passage are alternately stacked, and one open end of said passages is connected to a vacant space constituting said folded portion. The fuel reformer according to any one of claims 1 to 3. 7. A method according to claim 1, wherein said raw material gas introduction path, said reformed gas discharge path, and said gas supply path are stacked, and one open end of each of them is connected to an empty space constituting said folded portion. The fuel reformer according to claim 4 or claim 5, wherein 8. The reactor is formed by stacking a source gas introduction path, a reformed gas discharge path, a gas supply path, and a reformed gas discharge path in this order.
The fuel reforming apparatus according to claim 7, wherein one unit is formed, and the units are stacked. 9. The reactor according to claim 2, wherein the reactor comprises: an outer tube having an empty space on one end side of the folded portion; and an inner tube disposed inside the outer tube and connected to the empty space. The flow in the gas flow path formed by the heavy pipe and formed in the inner pipe is opposed to the flow in the gas flow path formed between the outer pipe and the inner pipe. The fuel reformer according to claim 4. 10. The reactor comprises: an outer tube having an empty space on one end side that constitutes the folded portion; and a plurality of inner tubes disposed inside the outer tube and connected to the empty room. The flow in the gas flow path formed in each inner pipe is opposed to the flow in the gas flow path formed between the outer pipe and each inner pipe. The fuel reformer according to any one of claims 1 to 4. 11. The fuel reformer according to claim 10, wherein a part of the inner pipe forms the gas supply passage. 12. The fuel reformer according to claim 1, wherein a volume of the raw gas introduction passage is smaller than a volume of the reformed gas discharge passage. 13. The catalyst is arranged such that the inlet side end of the catalyst filled in the raw material gas introduction passage is located closer to the turn-back side than the outlet side end of the catalyst filled in the reformed gas discharge passage. The fuel reformer according to any one of claims 1 to 12, wherein the fuel reformer is provided.