JP2002003204A - Fuel reformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel reformer capable of keeping the temperature of a reformer vessel at a low level, high in both heat efficiency and efficiency of conversion to reformed gas, and easy to manufacture. SOLUTION: This fuel reformer is provided with a reformer vessel 1 having a fuel gas inlet 9 and a reformed gas outlet 10, and the reforming regions 3, 4 and 19 which are provided in the reforming vessel 1 through the heat insulating materials 2 and in which the organic carbon-containing fuel gas introduced from the fuel gas inlet is reformed into a hydrogen-rich reformed gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel reformer for producing a hydrogen-rich reformed gas from a fuel gas such as natural gas supplied to a fuel cell.

[0002]

2. Description of the Related Art A fuel cell heats a fossil fuel such as methane, propane or natural gas to a high temperature to generate a reformed gas having a high hydrogen content, and uses the reformed gas as a fuel.

[0003] As a method of reforming the fuel gas, steam reforming (endothermic reaction) by a method of reacting organic carbon in the fuel gas with water vapor under heating conditions, and organic carbon by an oxidizing agent (oxygen gas or air). There are partial oxidation reforming (exothermic endothermic reaction) in which organic carbon and water vapor are reacted using heat generated by burning, and reforming (exothermic reaction) in which organic carbon and oxygen are directly reacted. However, each of the reforming methods and reformers disclosed so far has advantages and disadvantages.

[0004] Steam reforming (endothermic reaction) is a method in which a fuel gas reacts with an oxidant and the heat generated by combustion is transferred to organic carbon, steam and a catalyst through an isolation wall, or a heater by a storage power supply is used to generate the organic gas. A common method is to heat carbon, water vapor, and the catalyst. Of the two methods, in the former case, heat is transmitted through the separating wall, so that heat loss occurs and the startability is poor due to a delay in heat transfer. In addition, there is a drawback that the temperature controllability is poor, and the temperature of the reformer container tends to be partially high. On the other hand, in the latter case of the heater heating method using the storage power supply, although temperature controllability and startability are slightly improved as compared with the former, auxiliary equipment such as a storage power supply is required.

In partial oxidation reforming (exothermic endothermic reaction), combustion of an organic carbon by an oxidizing agent and catalytic reforming reaction of organic carbon and steam proceed simultaneously in the same place. The heat capacity is small and the startability is improved. However, harmful olefins are likely to be generated in a polymer electrolyte fuel cell. When the amount of the oxidizing agent is increased, the generation of olefin is reduced, but the conversion efficiency to the reformed gas is reduced. Also,
The temperature of the catalyst also tends to be partially non-uniform.

[0006] In recent years, a reforming method (exothermic reaction) for directly oxidizing organic carbon with oxygen without using steam has been studied, but the reaction temperature is high and the effect on the material of the reformer vessel and catalyst is affected. And the generation of olefins could not be completely suppressed.

[0007]

In the temperature design of a fuel reformer, the higher the temperature of the catalytic reaction layer is, the more advantageous in terms of reforming efficiency, but on the other hand, from the viewpoints of corrosion, thermal stress generation and economy. Therefore, the temperature of the fuel reformer vessel should be as low as possible.

[0008] For the reforming method using steam, a reformer that suppresses the generation of heat loss, has excellent startability, and generates less olefins harmful to a fuel cell is required. On the other hand, for reforming (exothermic reaction) in which organic carbon and oxygen are directly reacted, the generation of olefins is suppressed and organic carbon is reduced.
Nearly 100% conversion is required. Further, it is a common problem for both to suppress the occurrence of heat loss, to efficiently utilize the generated heat, and to suppress the temperature of the reformer container.
Another important issue is to apply economical materials that can withstand long-term operation and to improve manufacturability.

Accordingly, an object of the present invention is to provide a fuel reformer which can keep the temperature of a reformer vessel low, has high thermal efficiency and high conversion efficiency to reformed gas, and is easy to manufacture.

[0010]

According to a first aspect of the present invention, there is provided a reformer container having a fuel gas inlet and a reformed gas outlet, and the fuel gas provided in the reformer container via a heat insulating material. A reforming region for reforming a fuel gas containing organic carbon introduced from an inlet into a reformed gas having a high hydrogen content. According to the present invention, it is possible to provide a fuel reformer in which the heat loss to the outside is small and the temperature of the reformer container is low.

According to a second aspect of the present invention, the reforming region includes a heat generating region that generates heat by a combustion or oxidation / reforming reaction at a high temperature, and a gas generated by burning or oxidizing / reforming and steam or steam and organic carbon. And a catalyst region having a catalyst and performing a high-temperature steam reforming reaction at a high temperature. In the fuel reformer of the present invention, the reforming reaction of the fuel gas can proceed efficiently.

According to a third aspect of the present invention, a preheating region for preheating fuel gas is provided upstream of the reforming region at a portion outside the heat insulating material or inside the heat insulating material and near the reformer container wall. Features. In the fuel reformer of the present invention, heat generated in the reforming region can be effectively used.

According to a fourth aspect of the present invention, at least two of the preheating region, the heating region, the mixing region, and the catalyst region are combined and integrated. According to the present invention, the size of the fuel reformer can be reduced, or the efficiency of the reforming reaction can be increased.

According to a fifth aspect of the present invention, in the heating region,
The fuel gas is oxidized and reformed as a flame by a gas reaction with an oxidizing agent or using a catalyst. According to the present invention, the fuel gas can be efficiently heated.

According to a sixth aspect of the present invention, the heat generating area has a temperature sensor such as a thermocouple, and the temperature is raised to 400 ° C. or more by heating with an electric heater or the like before the fuel gas flows, and then the gas is flowed. After the temperature rises after the inflow, the heating of the electric heater or the like is stopped.

When the fuel reformer is started, it takes time to start if the temperature of the heat generating portion is low. According to the invention of claim 6, the temperature of the catalyst in the heat generating region is increased, and the reforming is performed together with the gas inflow. The reaction proceeds. Since the heat capacity of the catalyst is small, the starting time can be shortened.

According to a seventh aspect of the present invention, when oxidized as a flame, the portion of the flame which is heated to high temperature has a flame cover made of a heat-resistant material having a hole outside the hollow cylinder structure or the hollow cylinder structure where the flame exists. Features. According to the present invention, the reforming reaction can proceed stably while maintaining the stability of the flame.

[0018] The invention according to claim 8 is characterized in that the catalyst region is heated by directly mixing the fuel gas with the gas which has been heated to a high temperature by the combustion or oxidation / reforming reaction, in addition to heat transfer and radiation. And According to the present invention, heat generated by combustion or oxidation / reforming reaction can be effectively used.

A ninth aspect of the present invention is characterized in that the heat generating region, the catalyst region, and the mixing region are provided with a heat-resistant metal or ceramic having a large specific surface area.
According to the present invention, the probability of the reaction of the fuel gas is increased,
The reforming reaction can proceed efficiently.

A tenth aspect of the present invention is characterized in that the heat-resistant metal is tungsten, tantalum, molybdenum, vanadium, nickel, or an alloy containing at least one of these metals as a main component.

An eleventh aspect of the present invention is characterized in that the ceramic is mainly composed of alumina, zirconia, titania, magnesia, thoria, beryllia, yttria, or one or more of these substances. According to the invention of claim 10 or 11, it is possible to provide a high-reliability, long-life fuel reformer having high heat resistance in the heat generation region, the catalyst region, and the mixing region.

According to a twelfth aspect of the present invention, the catalyst held in the heat generation region or the catalyst region is mainly composed of a rare earth element such as rhodium, platinum, ruthenium, nickel, lanthanum, or at least one of these elements. It is characterized by. According to the present invention, the reforming reaction of the fuel gas at a high temperature can efficiently proceed.

The invention according to claim 13 is characterized in that the heat insulating material is a material having high airtightness and heat resistance. According to the present invention, it is possible to provide a fuel reformer having high material efficiency and high thermal efficiency by preventing fuel gas or reformed gas from dissipating through a heat insulating material or preventing low-temperature gas from entering.

The invention according to claim 14 is characterized in that the reformer container is made of a Ni-based alloy or Fe-based alloy having corrosion resistance at a high temperature, or has a ceramic layer formed on the inner surface of the alloy. ADVANTAGE OF THE INVENTION According to this invention, the problem of heat resistance and corrosion of a reformer container can be avoided, and the fuel reformer which can be operated for a long period of time can be provided.

According to a fifteenth aspect of the present invention, the reformer container has a main body having a built-in reforming region and a lid having no built-in reforming region, and the main body and the lid are joined to each other. It is characterized by the following. According to the present invention, it is possible to provide a fuel reformer which is easy to assemble and manufacture.

In the fuel reformer of the present invention, the following means are employed in order to suppress the generation of heat loss, efficiently use the generated heat, and suppress the temperature of the reformer container. That is, important material specification conditions of the reforming container are to ensure deformation and corrosion resistance under operating conditions and to maintain airtightness. In the case of steam oxidation, partial oxidation and direct oxidation, a higher temperature of the catalyst in which these reactions proceed is advantageous from the viewpoint of thermodynamics and selectivity of the catalyst, and is preferably 700 ° C. or higher. Therefore, the temperature of the reformer container is shielded from the high temperature part by the heat insulating material. Thereby, the temperature of the reformer container can be reduced. Further, it is possible to prevent high-temperature gas from leaking, and to lower the temperature of the reformer container. Thereby, corrosion and thermal stress of the reformer container material can be reduced.

In the present invention, a heat generating region which is a heat generating portion, a mixing region in which the high temperature gas obtained in the heat generating region and the fuel gas are mixed to a predetermined temperature, a catalyst region for performing steam reforming, The preheating area for preheating the supply gas is arranged in the same vessel, and the gas is mixed and heat is transferred so that heat can be efficiently used.

The present invention also provides a heat-generating region, a heat-generating region, and a heat-generating region by arranging a high-temperature portion at the center of the container away from the wall of the reformer container with a packing having a heat shielding effect. The mixing area where the obtained high-temperature gas and fuel gas are mixed to achieve a predetermined temperature and the catalyst area for reforming using the heat of the high-temperature gas are closest to each other, and heat from heat radiation and heat conduction is also effective. The temperature of the reformer container can be kept low because it is used and the preheating region of the supply gas is arranged in the same container.

Further, in the present invention, in selecting the material of each component, the following means are employed in order to reduce the temperature of the reformer vessel and maintain the temperature of the internal structural members at an appropriate temperature. In other words, in order to keep the reformer vessel temperature at 700 ° C or less and enable long-term operation, the fuel gas used was desulfurized, but corrosion-resistant materials were selected from the viewpoint that they could not be completely removed. 500 ° C for Fe-based alloys
Hereinafter, the Ni-based alloy is subjected to a high-temperature oxidation treatment at a temperature of 700 ° C. or less for about 20 hours to form an anticorrosive film and to reduce heat conduction.

On the other hand, in a high-temperature part operated at a temperature of 700 ° C. or more, a corrosion-resistant material capable of withstanding a high temperature of 1200 ° C. or more was selected as a substrate. Further, in order to suppress the temperature rise of the catalyst to 1000 ° C. or less, a temperature reduction effect is obtained by dispersing the catalyst in a corrosion resistant material. In this way, the anticorrosion property and airtightness are maintained under the use environment such as the temperature and the gas composition under the operating conditions.

The fuel reformer is quickly heated by combustion of a gas of a fuel and an oxidant or an oxidation reaction using a catalyst. Therefore, there is naturally an upper limit for the operating temperature conditions of the catalyst and the heat-resistant material in the reformer container. Catalyst metals such as Pt and Rh have a vapor partial pressure of 10 ^-11 mmHg at 1300 ℃
, The deterioration becomes remarkable. The long-term use limit is 1500 ° C for Ru with high vapor partial pressure and 1000 ° C for Ni with low vapor partial pressure.
Becomes

On the other hand, since the amount of the porous material supporting the catalyst is about 100 times that of the catalyst, a vapor partial pressure of 10 ^-13 mmHg is required. Therefore, when Rh is used as a catalyst, alumina is inappropriate and it is necessary to use other ceramics such as zirconia. Therefore, particularly in the flame portion where the temperature becomes high, the flame is stabilized and the contact with the material in the high temperature region is avoided. Thereby, the influence on the catalyst and the heat-resistant material in the reformer container can be eliminated.

The airtightness is not so important for the catalyst and the heat-resistant material in the reformer vessel, but rather the heat resistance related to the evaporation of the substance is important. Corrosion-resistant materials such as heat insulating materials, porous materials and packing materials used in the reformer container have a vapor partial pressure characteristic considering the maximum temperature and other characteristics of the material used compared to a heat-resistant material having a melting point of 1500 ° C or more. Select by considering. Regarding the method of supporting the catalyst on the porous body, the catalyst can be efficiently attached in a gas phase or a liquid phase.

Rhodium (Rh), platinum (Pt), ruthenium (Ru), nickel (Ni), and lanthanum (La) are used as catalysts to oxidize organic carbon and oxygen to generate heat and generate hydrogen and the like. Among them, Rh has an excellent conversion rate to hydrogen and carbon monoxide. In the case of Rh, methane is oxidized almost at 100% under the most appropriate conditions and the amount of olefin is small, but it is difficult to obtain a yield of 100% other than methane. Considering practicality, it is not practical in terms of production technology control to supply methane to a polymer electrolyte fuel cell as it is. In the present invention, the problem is solved by using a reforming reaction with steam at the subsequent stage of the heat generation region.

Further, in the fuel reformer of the present invention, after packing, which does not require airtightness, a catalyst and a heat insulating material, is incorporated into one of the two partial containers, the other partial container is combined with a laser or the like. Can be easily manufactured by welding.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A fuel reformer according to various embodiments of the present invention will be described below. FIG. 1 shows the structure of the fuel reformer in the case of the catalytic oxidation heating system according to the first embodiment of the present invention.
That is, the inside of the reformer container 1 having a cylindrical airtight structure is thermally shielded by the heat insulating material 2. Further, a heat generating region 3 made of a disc-shaped porous body and a catalyst region 4 mainly composed of steam reforming are formed inside the cylindrical heat insulating material 2 and a preheating region 5 is defined outside the heat generating region 3. ing.

Reference numeral 6 denotes a fixed guide attached to the inner wall of the reformer vessel 1. A cylindrical packing 7 is supported by the fixed guide 6, and the heat generating area 3 and the catalyst area 4 are provided at an intermediate portion of the packing 7. Are provided with their outer peripheries connected by a heat transfer tube 8. In addition, the preheating area 5
A gas inlet pipe 9 is connected to an upstream side of the fuel cell, and a gas outlet pipe 10 is connected to a downstream side of the catalyst region 4.

In the fuel reformer having such a configuration, the fuel gas, the oxidizing agent, and the gas such as water vapor are supplied from the gas inlet pipe 9 to the outer cylinder portion of the reformer container 1 and the heat insulating material 2. It enters the heating area 5 and is heated here, passes through the heat insulating material 2, the packing 7 and the opening 11 of the fixing guide 6,
The temperature is raised by the combustion reaction in the heat generating region 3, reformed in the catalytic region 4, and flows out from the gas outlet pipe 10.

As described above, the fuel reformer of the present embodiment has a structure of self-heating supply and gas flow passage which are combined and integrated. The heat generated by the oxidation reaction in the heat generating region 3 heats the reformed gas and is transmitted to the catalyst region 4 by heat transfer by the heat transfer tube 8 and is also used for the reforming reaction by steam.

Here, the reformer container 1, the heat insulating material 2, the packing 7, the heat transfer tube 8, and the fixed guide 6 are generally cylindrical, and the heat insulating material 2 at the end of the reformer container 1, Although 3 and catalyst region 4 are disk-shaped, they may be polygonal rather than disk-shaped. Further, the packing 7 may be inserted between the heat generating region 3 and the catalyst region 4 and may be separated therefrom. Further, instead of one disk, a plurality of thin disks may be superimposed, and the heat transfer tube 8 may not be provided. FIG.
Although no heat insulating material is shown on the inner wall and the outer wall of the cylindrical portion of the reformer container 1, it is desirable to provide a heat insulating material from the viewpoint of suppressing heat leak and keeping the temperature warm.

It is desirable that the heat insulating material 2 is a material having high airtightness and heat resistance. The heat generating region 3 for generating heat by the oxidation / reforming reaction and the catalyst region 4 for steam reforming are formed by attaching a catalyst to a heat-resistant material such as metal or ceramics, or heat-resistant alloy of a catalyst and a corrosion-resistant material. It is preferable to use a material having a large specific surface area made of a conductive material.

The material having a large specific surface area is preferably a disk-shaped porous material having a fine shape such as a fiber, a mesh, a honeycomb or a monolith, and having a large surface area and a small differential pressure rise. Alternatively, in the case where the fine shape forming these porosity is granular, the disk is placed in a heat-resistant metal container having fine porosity on both end surfaces of the disk.

FIG. 2 shows an embodiment of a heat-resistant porous disk used for the heat generating region 3 and the catalyst region 4. That is, if the fine structure forming the porous body 12 is granular,
(A) As shown in FIG. In the figure, fine pores 14 are formed at both ends of the disk so that gas flows, and fins 15 for improving heat conduction are attached to one surface thereof. Further, as shown in (b), the porous disk may have a structure in which a heat-resistant heat transfer metal rod 16 for improving heat conduction is embedded.

The gap through which the gas in the porous body 12 flows preferably has about 30 holes of about 200 μm in diameter per cm, and has a porosity of about 80% in order to suppress a rise in differential pressure. .

Here, a temperature sensor and an electric heater are provided outside the heat-resistant porous catalyst in the heat-generating region 3 or on the catalyst portion, and have a means for heating before the fuel gas flows for the first time. Is also good.

The heat insulating material 2 and the packing 7 provided in the reformer 1 are preferably made of a heat-resistant material which is a ceramic or metal having a high melting point or a composite material of ceramic and metal.

As the material of these ceramics, alumina, zirconia, titania, magnesia, thoria, beryllia, yttria, or a material containing at least one of these compounds as a main component is preferable. Further, as a material of the metal, dangsten, tantalum, molybdenum, vanadium, nickel, or an alloy mainly containing one or more of these metals is preferable.

The material of the catalyst used in the heat generating region 3 or the catalyst region 4 is rhodium (Rh), platinum (P
t), a rare earth element such as ruthenium (Ru), nickel (Ni), lanthanum (La), or a metal or oxide having at least one of these elements as a main component is preferable.

As a method for attaching these catalysts to the porous body, the catalyst can be attached by spraying, vapor deposition, physical vapor deposition, chemical vapor deposition, immersion in a solution, electrochemical or electromagnetic methods.

The maximum catalyst temperature of the heat generating region 3 for oxidation and reforming and the catalyst region 4 for steam reforming is R
1500 ° C for u, 1300 ° C for Rh and Pt, L
The upper limit is 1100 ° C. for a and 1000 ° C. for Ni.

As the material of the reformer container 1 requiring airtightness, a Ni-based alloy or a Fe-based alloy having corrosion resistance at high temperature or a material having a heat insulating function by attaching ceramics to the inner surface of these alloys is used. Good.

As a method of adhering the ceramics to the inner surface of the reformer container 1, a method of performing oxidation treatment, thermal spraying, or the like with air at high temperature, steam or a mixed gas thereof can be used.

As the Ni-based alloy, any one of Inconel 718, Inconel 600, Inconel 690, Inconel # 600 and Inconel # 690 is used. Further, any of SUS304, SUS316 and SUS310 is preferably used as the Fe-based alloy.

In the present embodiment, the catalyst region 4 for reforming with steam is provided. However, in the case where the fuel gas is a low-molecular organic carbon such as methane, ethane or ethanol, which is easily oxidized, When the Rh catalyst is used, direct oxidation in the heat generating region 3 according to the following equation (1) is possible, and a structure without the catalyst region 4 may be used. _{CH 4 + 0.5O 2 → CO +} 2H 2 - 8.5kJ / mol (1)

Rh is superior to Pt as a catalyst for reforming fuel gas by direct oxidation. Rh is attached to Al ₂ O ₃ having a specific surface area of about 10 m ² / g by several% by weight and 1 cm
Almost 100% is directly oxidized using a 10 mm thick, 18 mmφ porous monolithic disc-shaped catalyst having about 30 holes per unit to obtain hydrogen and carbon monoxide. ZrO ₂ is excellent as a corrosion-resistant material supporting a catalyst.

For methane and ethane, which can be easily reformed by direct oxidation, high-quality reformed gas can be obtained by adding steam within a range of 10% or less and making the length of the catalyst region 4 15 mm or more. it can. In addition, organic carbon other than methane, which is not easily oxidized, is subjected to a combustion reaction by a catalyst and the heat is used for steam reforming, whereby a high-quality reformed gas can be obtained.

As the carbon number of the organic carbon increases, the generation of olefin and the like cannot be ignored. In this case, when steam is added to the fuel gas in addition to the organic carbon and the oxidizing agent, generation of olefins and the like is suppressed. Further, when the catalyst region 4 is provided in the subsequent stage, steam reforming is performed by the reaction of the following equation (2), and the catalyst is converted into carbon monoxide and hydrogen. _{C n H 2n + nH 2 O} → nCO + 2nH 2 (2)

The carbon monoxide generated in the equations (1) and (2) is converted into carbon dioxide gas by the following equation (3) in a shift reactor or a selection reactor provided after the fuel reformer. Is converted to hydrogen. CO + H ₂ O → CO ₂ + H ₂ −9.8 kJ / mol (3) Therefore, the catalytic region 4 that causes a shift reaction or a selective reaction
May be provided in the low temperature region of the reformer.

FIG. 3 shows a fuel reformer according to a second embodiment of the present invention. In this embodiment, the reformer container 1
A gas inlet pipe 9 is connected to an end face of the heat exchanger, and a preheating area 5, a heat generation area 3, and a catalyst area 4 are provided inside the heat insulating material 2 inside the reformer vessel 1 along the flow of gas.

Good heat conductivity is provided at the contact portion between the heat insulating material 2 and the heat generating region 3 and the catalyst region 4, and at the outer cylindrical portion of the preheating region 5 at the contact portion between the heat insulating material 2 and the packing 7 in front of the heat generating region 3. A heat transfer material such as a heat-resistant heat transfer metal rod or the like is provided such that a heat-resistant metal coating or a thin plate is provided, and a porous body in the heat generation region 3, the preheating region 5, and the catalyst region 4 penetrates in the direction of the central axis of the cylinder. May be provided along the central axis of the reforming vessel. Then, the heating efficiency of the preliminary heating region 5 and the catalyst region 4 can be improved by utilizing heat conduction.

The preheating area 5 is required to have a function of transmitting the heat generated in the heat generating area 3 to the gas upstream portion by heat conduction and transmitting the heat to the gas at the upstream time point, and the differential pressure of the gas is not increased so much. Is required. Therefore, among the heat-resistant materials, a metal material is preferable. Also,
Honeycomb or the like is advantageous in terms of its shape from the viewpoint of heat transfer with gas and suppression of differential pressure.

The manufacture of the fuel reformer according to the present embodiment is performed as follows. That is, the reformer container 1 can be divided at the part of the dividing line A in FIG. 3, and a screw or a screw capable of adjusting the manufacturing tolerance of the heat insulating material 2 having a certain degree of airtightness in the internal structure at the divided connection part. A structure that can be inserted with a step is used. Left and right gas inlet piping 9 and gas outlet piping
A heat insulating material 2 is attached to a wall portion inside the fixed guide 6 to which 10 is connected by thermal spraying. In the case where the heat insulating material 2 moves in a case where the heat insulating material 2 at this portion has a fitting ring shape, the fixing can be performed by inserting a ring of the same material as the fixing guide 6 and welding the fixing guide 6 to the ring.

Next, the packing 7 is put on the right fixing guide 6, and the cylindrical heat insulating material 2 is inserted. Next, after inserting the disk-shaped catalyst region 4, the heat generating region 3 and the preheating region 5, the left packing 7 is inserted. Finally, the container on the left side of the dividing line A is inserted and inserted, and the overlapping portion is welded.

In this way, an integrated fuel reformer with high heat utilization efficiency, which easily incorporates the preheating region 5, the heat generation region 3, and the catalyst region 4 having an airtight structure, can be manufactured.
In addition, the sealability may be enhanced by interposing a seal packing made of a soft metal at the divided connection portion between the heat insulating material 2 and the container 1.

As described above, the fuel reformer of the present embodiment is
It has a fixing guide 6 for fixing the internal structure, and has a cylindrical or polygonal reformer vessel 1 divided into two parts to which a gas inlet 9 and an outlet 10 are attached. After sequentially inserting the structures, the flow path inside the container was formed by connecting and fitting the lid of the other container, and the airtightness was provided by welding the overlapping part of the body of the container. It is a structure.

The outer shapes of the reformer container 1 and the internal structure are simple shapes such as a cylinder, a column, and a disk. Welding is minimally required only on the side branch pipes and on the outside of the vessel body to prevent gas leakage. The fixed guide 6 and the burner can also be used with a screw-in type. The other contact portion is an economical manufacturing method in which the flow path can be secured even inside the container by a fitting method.

Next, a fuel reformer according to a third embodiment of the present invention will be described with reference to FIG. In this embodiment, a heating system using a flame is used instead of the oxidation heating system using the catalyst of the first and second embodiments. The point that the preheating region 5 for the fuel gas is outside the heat insulating material 2 is the same as in the first and second embodiments. The supply ports for the fuel gas and the combustion gas are separated. Fuel gas, which is a mixed gas of organic carbon and water vapor, is introduced from a gas inlet pipe 9. on the other hand,
Combustion gases such as organic carbon and an oxidant (which may partially contain water vapor) are introduced from a combustion gas supply pipe 17.

The combustion gas is burned into a flame, and a burner made of a hollow cylindrical heat-resistant metal material surrounding the flame.
A mixing region 19 made of a porous heat-resistant material for completely mixing the combustion gas and the fuel gas is provided. Here, the material of the metal constituting the burner 18 is preferably tungsten, tantalum, molybdenum, vanadium, nickel, or an alloy containing at least one of these metals as a main component. The heat-resistant material forming the mixed region 19 is preferably a metal or a ceramic, both of which have a large specific surface area.

The material having a large specific surface area is a disk-shaped porous material having a fine shape such as a fiber, a mesh, a honeycomb or a monolith, and having a large surface area and a small differential pressure rise, or a material having a large differential pressure. When the fine shape to be formed is granular, it is preferable that the disk is placed in a heat-resistant metal container having fine pores at both end surfaces. The material such as the porous body is desirably a ceramic or metal having a high melting point, or a composite material of ceramic and metal.

The metal is the above-mentioned tungsten or the like, and the material of the ceramic is preferably a material mainly containing one or more of alumina, zirconia, titania, magnesia, thoria, beryllia, and yttria.

The mixing region 19 is unnecessary if the combustion gas and the fuel gas coming out of the perforations of the burner 18 made of a heat-resistant metal material in a hollow cylindrical shape can easily mix with the flame. Although FIG. 4 shows a modification of FIG. 1, a structure in which the fuel gas inlet pipe 9 is provided on the end face of the reformer container 1 along with the combustion gas supply pipe 17 similarly to FIG.

As described above, the fuel reformer of the present embodiment is
Organic carbon is used as the fuel gas for combustion and reforming, and air or oxygen is used as the oxidizing agent. Steam is added to these gases, and the heat generated by the oxidation is obtained by mixing the directly oxidized and partially oxidized gas with the fuel gas. Is used for a steam reforming reaction.

Here, the reaction will be described taking the case where the combustion gas is methane as an example. In the combustion reaction, methane and oxygen separately introduced from the combustion gas supply pipe 17 become a flame (oxidation reaction) by the burner 18. The oxidation reaction depends on the temperature of the gas after combustion, but is generally intermediate between the complete oxidation and the partial oxidation shown in the following equations (4) and (5). CH ₄ + 2O ₂ → CO ₂ + 2H ₂ O −191.8 kJ / mol (4) CH ₄ + 1.5O ₂ → CO + 2H ₂ O −124.1 kJ / mol (5)

The high-temperature gas generated by the reactions of the equations (4) and (5) is mixed with methane and steam in the fuel gas introduced from the gas inlet pipe 9 in the mixing zone 19,
The temperature rises above. By passing this mixed gas through the catalyst region 4, a steam reforming reaction according to the following equation (6) proceeds. The heat generated by the burner 18 is used for the endothermic reaction of the formula (6). CH ₄ + H ₂ O → CO + 3H ₂ +49.2 kJ / mol (6)

Next, a fourth embodiment of the present invention will be described with reference to FIG. This embodiment is a fuel reformer of an oxidation heating system using a catalyst. The supply ports for the fuel gas and the combustion gas are separated. The preheating zone 5 for the fuel gas is outside the insulation 2. The heat-generating region 3 is sealed in a perforated cover basket made of a heat-resistant metal material made of a hollow porous ceramic with a catalyst. The materials of the cover basket, ceramics, and catalyst that constitute the heat generating region 3 are the same as those in the first or third embodiment.

Fuel gas, which is steam or a mixed gas of organic carbon and steam, is introduced from a gas inlet pipe 9. Combustion gas containing organic carbon, an oxidant and a small amount of water vapor is introduced from a combustion gas supply pipe 17. The combustion gas and the fuel gas are mixed in a mixing region 19 made of a porous heat-resistant material, reach a predetermined temperature, and flow into the catalyst region 4. When the combustion gas and the fuel gas are easily mixed sufficiently, the mixing region 19 is unnecessary. Further, the fuel gas inlet pipe 9 may be provided on the end face of the reformer container 1 side by side with the combustion gas supply pipe 17.

Here, the reaction will be described taking as an example the case where the organic carbon in the fuel gas and the combustion gas is propane. As the combustion reaction, propane and oxygen separately introduced from the combustion gas supply pipe 17 mainly cause a partial oxidation reaction in the heat generating region 3. A substance having a large number of organic carbons, such as propane, is not completely converted into carbon monoxide and hydrogen, and production of an intermediate product such as an olefin cannot be avoided. In this case, if steam is present in the combustion gas, the amount of olefin produced can be suppressed by the reaction of the above formula (2). Further, the fuel gas consisting of propane and water vapor introduced from the gas inlet pipe 9 is mixed in the mixing region 19 to have a high temperature of 700 ° C. or more, and reacts with the water vapor by passing through the catalyst region 4 to produce carbon monoxide.
Turns into carbon dioxide and hydrogen.

Next, the fuel reformer of the fifth embodiment shown in FIG. 6 is also an oxidizing heating system using a catalyst, and a mixing region 19 made of a porous heat-resistant material in which combustion gas and fuel gas are mixed.
Is expanded to the position of the heat generating region 3. In this case, the porous heat-resistant material in the mixing region 19 has a hollow portion corresponding to the portion of the combustion heat generating portion to be inserted.

In the fuel reformer of this embodiment,
Since the volume of the mixing region 19 is large, the fuel gas composed of water vapor or water vapor and organic carbon is sufficiently mixed with the combustion gas, and a sufficient temperature rise is obtained.

In each of the above embodiments, the reformer vessel 1, the gas inlet / outlet pipe 9 attached to the reformer vessel 1,
10, a porous body used for the heat generating area 3, the mixing area 19, and the catalyst area 4, a cover and a container installed for the purpose of stabilizing the flame area and holding the catalyst area, and a reformer vessel for contacting and holding the porous body Fixed guides 6 provided at both ends of the gasket, packings 7 for fixing these portions, heat generated in the heat generating region 3 is supplied to a preheating region 5 of a gas provided inside the heat insulating material 2 or a steam reforming reaction. Catalyst area 4
The shape of the heat transfer tube 8 to be transmitted to the cylinder is a circular or polygonal disk shape, a hollow shape, a shape in which a part of one end face of the column shape is hollow, or a shape in which a part of one end face of the column shape is hollow. A structure in which the shape is formed into a hollow pillar shape and a disk shape, and these objects are attached to the reformer container by contacting, screwing, or welding to control the gas flow and suppress heat transfer to the outside. Can be obtained.

Here, the composition of the gas and the reforming reaction formula in each of the above embodiments are shown in FIG.

[0082]

According to the present invention, it is possible to provide a fuel reformer which can keep the temperature of the reformer vessel low, has high thermal efficiency and high conversion efficiency to reformed gas, and is easy to manufacture. . Further, it is possible to supply a fuel reformer suitable for a polymer electrolyte fuel cell which uses hydrocarbons as a fuel and has excellent startability and can be used for automobiles and home power supplies.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a fuel reformer according to a first embodiment of the present invention.

FIG. 2 is a view showing an example of a heat-resistant porous disk provided in a heat generation area, a catalyst area, or a gas mixing area of the fuel reformer according to each embodiment of the present invention.

FIG. 3 is a diagram showing a cross section of a fuel reformer according to a second embodiment of the present invention.

FIG. 4 is a diagram showing a cross section of a fuel reformer according to a third embodiment of the present invention.

FIG. 5 is a diagram showing a cross section of a fuel reformer according to a fourth embodiment of the present invention.

FIG. 6 is a diagram showing a cross section of a fuel reformer according to a fifth embodiment of the present invention.

FIG. 7 is a table collectively showing a gas composition and a reforming reaction formula in each embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Reformer container, 2 ... Insulation material, 3 ... Heating area, 4 ... Catalyst area, 5 ... Preheating area, 6 ... Fixed guide, 7 ... Packing, 8 ... Heat transfer tube, 9 ... Gas inlet pipe, 10 ... Gas outlet piping, 11: Open hole, 12: Porous body, 13: Porous container, 14: Porous, 15: Fin, 16: Heat transfer metal rod, 17: Combustion gas supply pipe, 18: Burner, 19: Combustion Mixing area of gas and fuel gas.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 8/04 H01M 8/04 G 8/06 8/06 G (72) Inventor Nagayoshi Ichikawa Kawasaki, Kanagawa Prefecture 2-1 Ukishima-cho, Ichikawasaki-ku, Japan Toshiba Hamakawasaki Plant Co., Ltd. (72) Inventor Michiro Hori 2-1 Ukishimacho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Yasuhiro Arai 2-1 Ukishima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term in the Toshiba Hamakawasaki Plant (reference) 4G040 EA01 EA02 EA03 EA06 EA07 EB03 EB04 EB11 EB12 EB14 EB18 EB32 EB42 EB46 EC02 EC03 EC04 4G069 AA03 AA15 BA01B BC38A BC42A BC68A BC70A BC71A BC71B BC75A CC17 CC25 DA06 EA02Y FA02 FA03 4G070 AA01 AB04 BA02 BB02 CA06 CA25 CB02 CB17 CB18 CC02 DA23 5H027 AA02 BA01 KK42

Claims (15)

[Claims] 1. A reformer container having a fuel gas inlet and a reformed gas outlet, and a fuel gas provided in the reformer container via a heat insulating material and containing organic carbon introduced from the fuel gas inlet. And a reforming region for reforming the gas into a reformed gas having a high hydrogen content. 2. The reforming region includes a heat generating region that generates heat by a high-temperature combustion or oxidation / reforming reaction, and a combustion / oxidation / reforming gas and a fuel gas comprising steam or steam and organic carbon. A mixing zone for mixing and raising the temperature,
2. The fuel reformer according to claim 1, further comprising a catalyst region having a catalyst and performing a steam reforming reaction at a high temperature. 3. A preheating region for preheating fuel gas is provided upstream of the reforming region at a position outside the heat insulating material or inside the heat insulating material and near the reformer container wall. 3. The fuel reformer according to 2. 4. The fuel reformer according to claim 3, wherein at least two of the preheating region, the heat generation region, the mixing region, and the catalyst region are combined and integrated. 5. In the heat-generating region, the fuel gas is oxidized by flame as a gas reaction with an oxidant or by using a catalyst.
The fuel reformer according to claim 2, wherein the fuel is reformed. 6. The heat generating area has a temperature sensor such as a thermocouple, and the temperature is raised to 400 ° C. or more by heating with an electric heater or the like before the fuel gas flows in, and then the gas is flown. 3. The fuel reformer according to claim 2, wherein heating of the electric heater or the like is stopped later. 7. When oxidized as a flame, the portion of the flame which becomes hot has a flame cover made of a heat-resistant material having a hole outside the hollow cylinder structure or the hollow cylinder structure where the flame exists. 6. The fuel reformer according to 5. 8. The catalyst region is heated by directly mixing a fuel gas and a gas heated to a high temperature by combustion or oxidation / reforming reaction in addition to heat transfer and radiation. A fuel reformer as described. 9. The fuel reformer according to claim 2, wherein the heat generation region, the catalyst region, and the mixing region are provided with a heat-resistant metal or ceramic having a large specific surface area. 10. The fuel reformer according to claim 8, wherein the heat-resistant metal is tungsten, tantalum, molybdenum, vanadium, nickel, or an alloy containing at least one of these metals as a main component. vessel. 11. The fuel reformer according to claim 8, wherein the ceramic is mainly alumina, zirconia, titania, magnesia, thoria, beryllia, yttria, or one or more of these substances. 12. The catalyst held in the heat generating region or the catalyst region is mainly composed of a rare earth element such as rhodium, platinum, ruthenium, nickel, lanthanum, or at least one of these elements. Item 3. A fuel reformer according to Item 2. 13. The fuel reformer according to claim 1, wherein the heat insulating material is a material having high airtightness and heat resistance. 14. The fuel according to claim 1, wherein the reformer container is made of a Ni-based alloy or a Fe-based alloy having corrosion resistance at a high temperature, or a ceramic layer is formed on an inner surface of the alloy. Reformer. 15. The reformer container has a main body having a reforming region therein and a lid having no reforming region therein, wherein the main body and the lid are joined to each other. Claim 1
A fuel reformer as described.