JP2002293506A - Reformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reformer capable of performing reaction with high efficiency and capable of supplying water to a reforming section by completely evaporating. SOLUTION: This reformer is equipped with a reforming reaction section 3 in which source fuel reacts with steam by steam-reforming in of catalysts heated with combustion heat of a burner 1 to produce hydrogen rich reformed gas. A heat transfer section 4 which heats the water to supply steam to the reforming section 3 by recovering exhaust heat of the combustion heat of the burner 1. An auxiliary heat exchanger which heats water, is provided, recovering heat from the side of a reaction part installed in a different direction, which heats a reforming catalyst 2 among the combustion heat of the burner 1 which heats the reforming catalyst 2 in the reforming reaction section 3, even if water does not completely vaporize due to the lack of the quantity of heat in the heat exchanger 4, water can be supplied to the reforming reaction section 3, completely vaporizing the water by heating with heat exchange in the auxiliary heat exchanger 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reformer for obtaining a hydrogen-rich reformed gas from a raw fuel.

[0002]

2. Description of the Related Art As a device constituting a fuel cell, a reformer for generating a hydrogen-rich reformed gas from a raw fuel is known. As shown in Japanese Patent Application Laid-Open No. 9-241002, this reforming apparatus includes a reforming reaction section filled with a reforming catalyst, a CO shift reaction section filled with a CO shift catalyst, and a CO oxidation catalyst. And a charged CO oxidation part,
In order to further supply water as steam to the reforming reaction section,
It is provided with a heat exchange part for heating water. Then, by passing the raw fuel and steam through the reforming reaction section while heating the reforming catalyst with the burner, a hydrogen-rich reformed gas can be generated by the steam reforming reaction by the action of the reforming catalyst. This reformed gas contains CO,
Since CO is poisoned by the fuel cell and lowers the electrode catalyst performance, the CO is first passed through a shift reaction section, subjected to a shift reaction by a CO shift catalyst to reduce the amount of CO in the reformed gas, and then to the CO oxidation section. Then, CO is oxidized by a CO oxidation catalyst to remove CO in the reformed gas to such an extent that the fuel cell is not poisoned.

Here, in the heat exchange section for heating the water to make it steam, the exhaust heat is recovered from the exhaust gas of the combustion gas of the burner for heating the reforming catalyst, or the sensible heat is generated from the generated reformed gas. Or water is heated by the recovered heat. Then, the steam obtained by heating the water in the heat exchange section is supplied to the reforming reaction section together with the raw fuel, and the reforming catalyst produces a hydrogen-rich reformed gas by the steam reforming reaction. Can be done.

[0004]

However, when water is heated and steamed with the recovered heat as described above, the amount of heat required for steaming water is slightly insufficient depending on the operating conditions of the reforming reaction section. There are cases. For example, when the ratio of raw fuel to water vapor (steam-carbon ratio) is large, that is, when the amount of water is large, the energy required to evaporate the water increases, so the heat recovered from the exhaust gas of the burner as described above In some cases, water alone cannot be completely steamed.

If water is supplied to the reforming catalyst in the reforming reaction section without being completely steamed, the reforming reaction becomes insufficient or the energy required for the remaining evaporation is reformed. For example, it has to be supplied directly into the reaction section, which causes a reduction in the overall efficiency of the reformer.

[0006] The present invention has been made in view of the above points, and there is provided a reforming apparatus capable of completely converting water into steam and supplying the water to a reforming reaction section, thereby allowing a reforming reaction to be performed with high efficiency. It is intended to provide.

[0007]

According to a first aspect of the present invention, there is provided a reforming apparatus comprising: a reforming catalyst heated by combustion heat of a burner;
The reforming reaction section 3 generates a hydrogen-rich reformed gas by causing a steam reforming reaction between raw fuel and steam by the action of, and recovers combustion exhaust heat from the burner 1 and supplies steam to the reforming reaction section 3. And a heat exchange unit 4 for heating water for heating the reforming catalyst 2 in the reforming reaction unit 3, the combustion heat of the burner 1 heating the reforming catalyst 2 is different from the direction in which the reforming catalyst 2 is heated. It is characterized by comprising an auxiliary heat exchange section 5 for recovering heat transmitted to the side of the reforming reaction section 3 and heating the water.

According to a second aspect of the present invention, in the first aspect, water for supplying steam to the reforming reaction section 3 by recovering heat from the reformed gas generated in the reforming reaction section 3 is heated. It is characterized by comprising second auxiliary heat exchange parts 6,7.

Further, according to a third aspect of the present invention, there is provided the method according to the first or second aspect, wherein CO contained in the reformed gas is oxidized and removed.
A third auxiliary heat exchange unit that includes a CO oxidation unit 8 filled with an O oxidation catalyst, recovers heat of the reformed gas in the CO oxidation unit 8, and heats water for supplying steam to the reforming reaction unit 3; 9 is provided.

According to a fourth aspect of the present invention, in any one of the first to third aspects, a burner 1 that burns a mixture of a fuel and an oxidant is used to supply steam to the reforming reaction section 3. The auxiliary heat exchanger 5 for heating water is connected to the burner 1
Are provided around the periphery.

A fifth aspect of the present invention is characterized in that, in any one of the first to fourth aspects, the auxiliary heat exchange section 5 is formed by winding a pipe 10 around the burner 1.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the reforming catalyst 2 is disposed in the reforming reaction section 3, and the burner 1 is formed so as to surround a side surface of the reforming catalyst 2. The combustion gas passage 11 is formed in the reforming reaction section 3.

According to a seventh aspect of the present invention, in any one of the first to sixth aspects, the burner 1 is disposed below the reforming catalyst 2 in the reforming reaction section 3. is there.

[0014]

Embodiments of the present invention will be described below.

FIG. 1 shows an embodiment of the present invention, in which a reforming reaction section 3 containing a reforming catalyst 2 and a burner 1 and a CO shift reaction section 15 filled with a CO shift catalyst are shown.
And a CO oxidizing unit 8 filled with a CO oxidizing catalyst, and a heat exchange unit 4 for heating water to form a reformer system.

The reforming reaction section 3 is provided at the center of the upper portion of the cylindrical vessel 16 with the reforming catalyst 2 disposed therein.
The reformer 2 is formed by arranging and providing the burner 1 in the lower portion of the container 16. By arranging the reforming catalyst 2 in a cylindrical shape (column shape) in this manner and arranging the reforming catalyst 2 in the central portion in the upper portion of the container body 16, A passage 11 surrounding the side surface of the reforming catalyst 2 over the entire circumference.
Is formed in the reforming reaction section 3. Also,
An auxiliary heat exchange unit 5 is provided on the outer periphery of the reforming reaction unit 3 in contact with the outer surface of the container 16. The auxiliary exchange section 5 is disposed so as to surround the side portion of the reforming catalyst 2 over the entire circumference.

In the reforming apparatus formed as described above, a mixed gas of fuel and air is supplied to the burner 1 through a combustion fuel passage 17, and this mixed gas is burned to form a reforming catalyst. 2 is heated. When the raw fuel and the steam are supplied from the raw fuel supply passage 18 to the reforming catalyst 2 of the reforming reaction section 3, the raw fuel and the steam are converted by the action of the reforming catalyst 2 heated by the combustion heat of the burner 1. The reforming reaction section 3 can generate a hydrogen-rich reformed gas through a steam reforming reaction. The reformed gas generated in the reforming reaction section 3 is passed through the reformed gas passage 19 to the shift reaction section 1.
5 and a shift reaction is performed by the CO shift catalyst to reduce the amount of CO in the reformed gas. Further, the reformed gas is sent to the CO oxidizing section 8 through the reformed gas flow path 20 and supplied to the CO oxidizing section 8 in a state of being mixed with air. In the CO oxidation section 8, CO in the reformed gas is oxidized by the CO oxidation catalyst, and the CO in the reformed gas is removed to such an extent that the fuel cell is not poisoned. The reformed gas from which CO has been removed in this way is:
The gas is supplied from the CO oxidizing section 8 to a fuel cell or the like through the reformed gas supply path 21.

Here, the reforming catalyst 2 can be heated by the combustion gas burned by the burner 1,
Also, when the combustion gas passes through the passage 11 surrounding the side portion of the reforming catalyst 2, the reforming catalyst 2 can be heated, and the reforming catalyst 2 can be efficiently heated. Then, the combustion exhaust gas is discharged from the exhaust gas passage 22, and is discharged after passing through the heat exchange unit 4. Water (reformed water) is supplied to the heat exchange unit 4, heat exchange with the combustion exhaust gas is performed in the heat exchange unit 4, and the exhaust heat of the combustion exhaust gas is recovered. Thus, superheated steam of 100 ° C. or more is produced.

The water (steam) heated by the heat exchange in the heat exchange section 4 is sent to the auxiliary heat exchange section 5 through the water flow path 23. Although the reforming catalyst 2 is heated by the combustion gas burned by the burner 1 as described above, the heat of the combustion gas is also radiated to a side different from the direction in which the reforming catalyst 2 is heated. The third body 16 is also transmitted. Thus, the heat transmitted to the body 16 of the reforming reaction section 3 is exchanged with the water in the auxiliary heat exchange section 5, and the water heated in the heat exchange section 4 is further heated. You can do it. Therefore, even if the amount of heat for heating in the heat exchange unit 4 is insufficient and the water is not completely turned into steam, the water can be completely turned into steam by heating by the heat exchange in the auxiliary heat exchange unit 5. A gas that can be sent to the fuel supply passage 18 and mixed with the raw fuel and supplied to the reforming catalyst 2 of the reforming reaction section 3 to generate a hydrogen-rich reformed gas by the steam reforming reaction as described above. It is.

FIG. 2 shows another example of the embodiment of the present invention. In this example, an auxiliary heat exchange is provided in a reformed gas flow path 19 between the reforming reaction section 3 and the CO shift reaction section 15. Part 6
The auxiliary heat exchange unit 7 is connected to the reformed gas flow path 20 between the CO shift reaction unit 15 and the CO oxidation unit 8. Further, the CO oxidizing section 8 is provided with an auxiliary heat exchange section 9 so as to surround the outer periphery of the vessel. And the reforming reaction section 3
The water (steam) sent out from the auxiliary heat exchange unit 5 provided around the water is transferred to the auxiliary heat exchange unit 7 in the water flow path 25, and after passing through the auxiliary heat exchange unit 7, After being transferred to the auxiliary heat exchange unit 9 of the CO oxidation unit 8 and further passing through the auxiliary heat exchange unit 9, the auxiliary heat exchange unit 6
After passing through the auxiliary heat exchange section 6, it is sent to the raw fuel supply path 18, mixed with the raw fuel, and supplied to the reforming catalyst 2 of the reforming reaction section 3. The other structure is the same as that of FIG.
Assuming that the first auxiliary heat exchange section recovers the combustion heat of the fuel gas, the auxiliary heat exchange sections 6 and 7 that recover the sensible heat of the reformed gas become the second auxiliary heat exchange section, and recovers the heat from the CO oxidation section 8. The auxiliary heat exchanging unit 9 that becomes the third auxiliary heat exchanging unit.

In the reforming apparatus shown in FIG. 2 formed as described above, when the raw fuel and steam are supplied from the raw fuel supply passage 18 to the reforming catalyst 2 of the reforming reaction section 3, the above-described processing is performed. As described above, the steam reforming reaction generates a hydrogen-rich reformed gas. The reformed gas generated in the reforming reaction section 3 is supplied to the reformed gas passage 19.
After passing through the auxiliary heat exchange unit 6 and sent to the shift reaction unit 15, where the shift reaction is performed by the CO shift catalyst to reduce the amount of CO in the reformed gas. Further, the reformed gas is transferred through the reformed gas flow path 20, passes through the auxiliary heat exchange unit 7, is sent to the CO oxidizing unit 8, and is supplied to the CO oxidizing unit 8 in a state of being mixed with air. In the CO oxidation unit 8, CO in the reformed gas is oxidized by the CO oxidation catalyst, and the CO in the reformed gas is removed to such an extent that the fuel cell is not poisoned. The reformed gas from which CO has been removed in this way is supplied from the CO oxidizing unit 8 to a fuel cell or the like through the reformed gas supply path 21.

As described above, water is first supplied to the heat exchange section 4.
And is heated and exchanged with the combustion exhaust gas of the burner 1 to be steamed. Next, the water (steam) is sent to the auxiliary heat exchange section 5, and exchanges heat with the combustion heat of the burner 1 radiated to the side of the reforming reaction section 3 to be heated. Then, the water (steam) flows from the auxiliary heat exchange section 5 through
It is sent to the auxiliary heat exchange section 7 between the O shift reaction section 15 and the CO oxidation section 8. This heat exchange section 7 includes a CO shift reaction section 1
The reformed gas sent through the reformed gas flow path 20 from the fuel gas 5 to the CO oxidizing unit 8 is passed. The reformed gas that has undergone this shift reaction has a sensible heat of about 250 ° C. When water passes through the auxiliary heat exchange unit 7, the water exchanges heat with the high-temperature reformed gas and is heated.

Water (steam) from the auxiliary heat exchange unit 7 passes through a water flow path 26 to the auxiliary heat exchange unit 9 on the outer periphery of the CO oxidation unit 8.
Sent to The CO oxidation reaction in the CO oxidation section 8 is generally 1
This is performed at around 40 ° C., and it is necessary to cool the CO oxidation reaction section 8 into which the high-temperature reformed gas is introduced to about 140 ° C., but the auxiliary heat exchange section 9 on the outer periphery of the CO oxidation section 8 By exchanging heat with water (steam)
The temperature is controlled so as to cool to around 140 ° C. By performing heat exchange with water for supplying steam to the reforming reaction section 3 in this manner, the temperature of the reaction temperature can be adjusted in the CO oxidizing section 8, so that a cooling device for temperature control is not required. That is, it is possible to reduce the auxiliary power in the fuel cell system.

The water (steam) heated in the auxiliary heat exchange section 9 on the outer periphery of the CO oxidation section 8 further passes through the water flow path 27 to the auxiliary heat exchange section 6 between the reforming reaction section 3 and the CO shift reaction section 15. Sent. Since the high-temperature reformed gas generated in the reforming reaction section 3 is sent from the reformed gas flow path 19 and passes through the auxiliary heat exchange section 6, water flows through the auxiliary heat exchange section 6. When passing, it is heated by exchanging heat with the high-temperature reformed gas.

In this way, the water heated in the heat exchanging section 4 can be further heated in the auxiliary heat exchanging sections 5, 6, 7, and 9. Even if the water is not completely steamed due to the shortage, the steam can be completely steamed by the heat exchange in the auxiliary heat exchange units 5, 6, 7, and 9, and this steam is sent to the raw fuel supply passage 18. It is fed to the reforming catalyst 2 of the reforming reaction section 3 in a state of being mixed with the raw fuel, and can generate a hydrogen-rich reformed gas by the steam reforming reaction as described above.

FIG. 3 shows another example of the embodiment of the present invention. In this embodiment, an auxiliary heat exchange section 5 provided on the outer periphery of the reforming reaction section 3 is provided with a vessel 16 of the reforming reaction section 3. Is formed so as to surround the periphery of the burner 1 provided at the lower part of the burner. Other components are formed in the same manner as in FIG.

Here, the burner 1 is formed as a premix burner for premixing and burning the raw fuel and combustion air as an oxidant. In such a premix burner, a flashback to the premix section is performed. Is a problem. For this purpose, the jet velocity and the hole diameter of the burner 1 are designed in consideration of the burning velocity of the mixed gas of the raw fuel and the oxidizing agent. However, the burning velocity of the mixed gas is physically proportional to the temperature. If the overheat exceeds the design value, flashback is likely to occur. In particular, as in the case of the fuel cell system, if the off-gas hydrogen not consumed by the fuel cell is burned by the burner 1, the hydrogen has the fastest burning speed among the fuels. Flashback is likely to occur.

Therefore, in the embodiment shown in FIG. 3, the auxiliary heat exchange section 5 provided in the reforming reaction section 3 and recovering the combustion heat radiated to the side is disposed around the burner 1, so that the burner 1 Can be cooled by the heat exchange by the auxiliary heat exchange section 5. Thus, the auxiliary heat exchange unit 5
By cooling the burner 1 by utilizing the method, it is possible to prevent the occurrence of flashback, thereby preventing damage to the equipment of the burner 1 and the stable operation of the reformer.

In the embodiment shown in FIG. 4, the auxiliary heat exchange section 5 around the burner 1 shown in FIG.
0 is formed. By forming the auxiliary heat exchange section 5 with the pipe 10 wound around the burner 1 in this manner, the amount of heat transfer can be easily adjusted by the number of turns of the pipe 10 around the outer periphery of the burner 1, and the reformer can be operated in practice. Even if it is found that the design of the auxiliary heat exchange unit 5 is insufficient or excessive in the evaluation after the above, it can be easily dealt with by changing the number of turns of the pipe 10, and the auxiliary heat exchange unit 5 Redesign and reprototyping are facilitated, and equipment costs can be significantly reduced.

In the embodiment shown in FIG. 4, the auxiliary heat exchange unit 5
Is formed by the pipe 10, but the other auxiliary heat exchange sections 6, 7, 9 may be formed in a manner in which the pipe 10 is similarly wound.

[0031]

As described above, the first aspect of the present invention generates a hydrogen-rich reformed gas by causing a steam reforming reaction between raw fuel and steam by the action of a reforming catalyst heated by the combustion heat of a burner. In a reforming apparatus including a reforming reaction section and a heat exchange section that heats water for recovering exhaust heat from the burner and supplying steam to the reforming reaction section, a reforming catalyst is provided in the reforming reaction section. The auxiliary heat exchange unit for recovering the heat transmitted to the side of the reforming reaction unit different from the direction in which the reforming catalyst is heated out of the combustion heat of the burner for heating the water and heating the water is provided. Even if the amount of heat in the exchange section is insufficient and the water is not completely steamed, the water can be completely steamed by heating by heat exchange in the auxiliary heat exchange section and supplied to the reforming reaction section. Yes, it is possible to generate a reformed gas by performing a steam reforming reaction with high efficiency. It is.

Further, the second auxiliary heat exchange section for recovering heat from the reformed gas generated in the reforming reaction section and heating water for supplying steam to the reforming reaction section. Therefore, even if the amount of heat in the heat exchange section is insufficient and the water is not completely turned into steam, the water is completely turned into steam by the heat exchange in the second auxiliary heat exchange section to reform the water. The steam can be supplied to the reaction section, and the steam reforming reaction can be efficiently performed to generate a reformed gas.

The invention according to claim 3 is characterized in that the CO contained in the reforming gas is filled with a CO oxidation catalyst for oxidizing and removing the CO contained in the reformed gas.
An oxidation unit is provided, and a third auxiliary heat exchange unit that heats water for recovering the heat of the reformed gas in the CO oxidation unit and supplying steam to the reforming reaction unit is provided. Even if the amount of heat is insufficient and the water is not completely steamed, the water can be completely steamed and supplied to the reforming reaction section by heating by heat exchange in the third auxiliary heat exchange section. In addition, a reforming gas can be generated by performing a steam reforming reaction with high efficiency.

According to a fourth aspect of the present invention, a burner which burns a mixture of fuel and an oxidant is used as a burner, and an auxiliary heat exchange section for heating water for supplying steam to the reforming reaction section is provided. Since it is provided on the periphery, it is possible to prevent the occurrence of flashback by cooling the burner using the auxiliary heat exchange unit.

According to the fifth aspect of the present invention, the auxiliary heat exchange portion is formed by winding the pipe around the burner, so that the amount of heat transfer can be easily adjusted by the number of turns of the pipe.
Even if the design of the auxiliary heat exchanger is found to be insufficient or excessive, it can be easily dealt with by changing the number of turns of the pipe.

In the invention of claim 6, the reforming catalyst is disposed in the reforming reaction section, and the combustion gas passage of the burner is formed in the reforming reaction section so as to surround the side surface of the reforming catalyst.
The reforming catalyst can be efficiently heated by the combustion gas of the burner, and the reformed gas can be efficiently generated.

According to the invention of claim 7, since the burner is arranged below the reforming catalyst in the reforming reaction section, the reforming catalyst can be efficiently heated by the combustion gas of the burner, and the efficiency can be improved. It can generate a high reformed gas.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment of the present invention.

FIG. 2 is a schematic diagram showing another example of the embodiment of the present invention.

FIG. 3 is a schematic diagram showing another example of the embodiment of the present invention.

FIG. 4 is a schematic diagram showing another example of the embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 burner 2 reforming catalyst 3 reforming reaction section 4 heat exchange section 5 auxiliary heat exchange section 6 auxiliary heat exchange section 7 auxiliary heat exchange section 8 CO oxidation section 9 auxiliary heat exchange section 10 pipe 11 passage

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Katsumi Haza 1048 Kazuma Kadoma, Kadoma-shi, Osaka F-term in Matsushita Electric Works, Ltd. (reference) 4G040 EA02 EA03 EA06 EB03 EB12 EB31 EB32 EB44 4G140 EA02 EA03 EA06 EB03 EB12 EB31 EB32 EB44 5H027 AA02 BA01 BA17

Claims (7)

[Claims] 1. A reforming reaction section for performing a steam reforming reaction between raw fuel and steam by the action of a reforming catalyst heated by the combustion heat of a burner to generate a hydrogen-rich reformed gas, and a combustion exhaust heat of the burner. And a heat exchange unit that heats water for supplying steam to the reforming reaction section, and reforming the combustion heat of the burner that heats the reforming catalyst in the reforming reaction section. A reforming apparatus comprising: an auxiliary heat exchange section that recovers heat transmitted to a side of a reforming reaction section different from a direction in which a catalyst is heated and heats the water. And a second auxiliary heat exchange unit for recovering heat from the reformed gas generated in the reforming reaction unit and heating water for supplying steam to the reforming reaction unit. The reforming apparatus according to claim 1, wherein: 3. A CO oxidizing section filled with a CO oxidizing catalyst for oxidizing and removing CO contained in the reformed gas, wherein heat of the reformed gas is recovered by the CO oxidizing section and steam is supplied to the reforming reaction section. 3. The reformer according to claim 1, further comprising a third auxiliary heat exchange unit that heats the water to be supplied. 4. 4. A burner which burns a mixture of fuel and oxidant as a burner, and an auxiliary heat exchange section for heating water for supplying steam to a reforming reaction section is provided around the burner. The reforming apparatus according to any one of claims 1 to 3, wherein 5. An auxiliary heat exchange part formed by wrapping a pipe around a burner.
The reforming device according to any one of the above. 6. The reforming catalyst is arranged in a reforming reaction section, and a combustion gas passage of a burner is formed in the reforming reaction section so as to surround a side surface of the reforming catalyst. 1
The reforming apparatus according to any one of claims 1 to 5. 7. The reforming apparatus according to claim 1, wherein a burner is arranged below the reforming catalyst in the reforming reaction section.