JP2000329309A - Catalytic combustion device - Google Patents

Abstract

(57) [PROBLEMS] A catalytic combustion device used in a fuel reformer for producing hydrogen by reforming methanol or a hydrocarbon fuel,
In particular, the present invention provides a catalytic fuel device that serves as a heat source for a vehicle fuel reformer. SOLUTION: This is a catalytic combustion device used for a fuel reforming device that generates hydrogen using hydrocarbons or alcohols as a reforming raw material, comprising a catalyst support layer, a fuel diffusion layer, and a fuel supply system. A catalytic combustion device characterized by the above-mentioned.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic combustion apparatus used in a fuel reformer for producing a hydrogen-rich gas by reforming methanol or a hydrocarbon-based fuel, and more particularly, to a heat source for an on-vehicle fuel reformer. And a catalytic fuel device.

[0002]

2. Description of the Related Art Conventionally, as a heat source of a fuel reforming apparatus, a burner type apparatus as shown in FIG. 4 or a catalytic fuel apparatus for gaseous fuel as shown in FIG. 5 has been used. In the burner-type apparatus, since air and fuel are put together and burned and flowed, if the fuel is rich, there is a risk of explosion and there is a problem in safety. Further, since the temperature of the combustion gas until the heat is received by the reforming side is very high, the heat efficiency is low, and the exhaust gas such as NOx and CO contains a large amount of toxic gas. Further, uniform heating is difficult, and the entire apparatus is also increased in size.

On the other hand, in a catalytic combustion apparatus for gaseous fuel, there is no problem as in the burner method. However, when liquid fuel is used, uniform diffusion of fuel is not performed and uniform heating is not performed. In particular, since the liquid fuel is not vaporized at the start, there is a problem that the non-uniformity is remarkable. That is, in the case of a gaseous combustible, uniform diffusion can be achieved even with a fuel injection hole of about several mm and a cotton-like porous body having a large porosity. However, in the case of liquid combustibles such as methanol, the injection amount varies depending on the position, inclination, and the like of the fuel supply holes, and furthermore, a material such as a cotton-like porous material having a large porosity cannot sufficiently diffuse. Was difficult.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, the inventors of the present invention have inferior safety and thermal efficiency as in the burner system, toxic exhaust gas such as NOx and CO, uneven heating, large size, etc. In order to develop a catalytic fuel system that solves the above-mentioned problems, we have conducted intensive studies. As a result, the present inventors have solved such a problem by enabling uniform heating of a catalytic combustion device that has conventionally been intended for a gaseous fuel by uniformly diffusing a liquid and supporting a liquid. I found something. The present invention has been completed from such a viewpoint.

[0005]

That is, the present invention relates to a catalytic combustion apparatus used in a fuel reformer for producing hydrogen using hydrocarbons or alcohols as a reforming raw material, comprising a catalyst support layer and a fuel diffusion layer. And a fuel supply system. In a fuel reformer, hydrocarbon or alcohol is used as a reforming raw material, and a hydrogen-rich gas is usually generated in a reformer. However, the catalytic combustion device of the present invention uniformly heats the reformer in such a reformer. It works to give Here, the catalyst support layer is preferably made of alumina ceramic fibers, and the specific surface area of the alumina ceramic fibers is preferably 10 m ² / g or more. It is preferable that 0.1 to 1.0% by weight of platinum is supported on the surface of the alumina ceramic fiber. Further, in the catalytic combustion device of the present invention, it is preferable that the fuel diffusion layer is made of a porous body in which ceramic fibers are bonded by, for example, a binder, and the density of the porous body is preferably 3 to 10% by weight of the theoretical density. More preferably, it is 5 to 8% by weight of the theoretical density. Further, the fuel supply system is preferably in contact with the fuel diffusion layer and has a fuel supply hole at the contact portion, and the diameter of the fuel supply hole is preferably 1 mm or less, more preferably 0.1 mm or less.
０．３0.3 mm.

According to the present invention, uniform heating can be performed using a liquid fuel. That is, the temperature distribution can be made uniform by uniformly diffusing the liquid fuel. In particular, it is effective at the start when the liquid fuel is not completely vaporized. The same effect can be exerted even in a state where it is not allowed to stand still or an inclined state. Also, the device can be made light and compact, there is little danger of explosion, CO, NO
Low toxic exhaust gas such as x. Further, by bonding the ceramic fibers with a binder or the like, a capillary phenomenon acts on the porous body, and the diffusion of fuel is promoted as compared with a porous body not bonded with the binder. Further, the diameter of the hole for supplying fuel is 1 mm or less, more preferably 0.1 to 0.3 m.
By setting m, the fuel can be uniformly diffused by uniformly dispersing the fuel by uniformly coming out of the fuel from all the holes. Hereinafter, the present invention will be described in detail.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The catalytic combustion apparatus of the present invention uses a hydrocarbon or an alcohol as a reforming raw material and applies heat to a reforming catalyst section for generating a hydrogen-rich gas. It has a diffusion layer and a fuel supply system. The catalyst support layer may be made of alumina ceramic fibers,
The specific surface area of the alumina ceramic fiber is 10 m ² / g.
It is preferable that it is above. Platinum is preferably carried on the alumina ceramic fiber surface in an amount of 0.1 to 1.0% by weight, more preferably 0.3 to 0.8% by weight. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Embodiment (No. 1) FIG. 1 shows a catalytic combustion apparatus according to the present invention, which comprises a catalyst support layer 1, a fuel diffusion layer 2, and a fuel supply system 3. The catalyst support layer 1 is made of alumina ceramic fibers, and the specific surface area of the alumina ceramic fibers is 1
0 m ² / g or more. Then, 0.1 to 1.0% by weight of platinum is supported on the surface of the alumina ceramic fiber. Such a catalyst support layer 1 has a specific surface area of 10 m ² /
g or more of the alumina ceramic fiber is impregnated with a dinitrodiamine platinum nitrate solution so that the platinum content is 0.5% by weight, dried at about 60 ° C., and calcined at about 250 ° C.

The fuel diffusion layer 2 is a porous body in which ceramic fibers are bonded by, for example, a binder, and the density of the porous body is preferably 3 to 10% by weight of the theoretical density, more preferably 5 to 8% by weight. It is. When the fuel diffusion layer 2 is a porous ceramic fiber, the liquid is further diffused when the density is 3% by weight or more of the theoretical density by the fibers being bonded by a binder or the like. As a method of bonding, bonding with an organic binder or calcination (1)
(Less than 000 ° C.) to combine the fibers with each other. The diffusion is promoted by the bonding because the capillary phenomenon is used as a diffusion method.If the fibers are not bonded to each other, the passage is destroyed by the internal pressure increased by the capillary phenomenon, and the diffusion proceeds further. It is because it disappears. The fuel supply system 3 is provided with, for example, a protrusion 7 that contacts a fuel diffusion layer on a thin flat box as shown in FIG.
A diameter of 1 mm or less, more preferably 0.1 to
A hole 6 having a diameter of 0.3 mm is formed. The diameter of the hole 6 is 1m
By setting m or less, the fuel is uniformly ejected from all the holes, and uniform diffusion becomes possible.

FIG. 6 shows a case in which the catalytic fuel device of the present invention is incorporated.
1 shows an example of a fuel reformer. This fuel reforming
The apparatus usually includes a vaporizing section 17, a reforming section 13, and a catalytic combustion section 1.
And 1. The vaporizing section 17 includes a reforming raw material (hydrocarbon
And methanol) and water 16 to vaporize.
For example, it is injected by a nozzle or vaporized by the heat transfer of the catalytic combustion unit 11.
Or let it. The reforming section (reforming catalyst section) 13 is made of Cu-Z
Hydrocarbons and methanols with n-based catalysts and Ni-based catalysts
From the reforming raw material and water (16) _TwoWhen
Hydrogen gas H_TwoThis is a part for generating (15). Catalytic combustion
Part 11 uses hydrocarbons or alcohols as reforming raw materials
Heat is applied to the reforming catalyst unit 13 that generates hydrogen-rich gas.
I can. As shown in FIG.
A catalytic combustion device is disposed, and the fuel 5 and the air 4 are injected.
It heats when it enters, and water H_TwoO and carbon dioxide CO_Two(1
2) is generated.

Embodiment (Part 2) As an example of the fuel supply system, there is a fuel supply system as shown in FIG. 3, for example, in addition to the embodiment of FIG. 2 in the embodiment (Part 1). The fuel supply system shown in FIG. 3 is made of pipes instead of boxes on a thin flat plate. Even when such a fuel supply system is used, similarly to the above-described embodiment (No. 1), a catalyst support layer and a fuel diffusion layer are provided. The catalyst support layer is preferably made of alumina ceramic fibers, and the fuel diffusion layer is preferably made of a porous body obtained by bonding ceramic fibers with a binder or the like.

[0012]

According to the present invention, uniform heating can be achieved using liquid fuel. That is, the temperature distribution can be made uniform by uniformly diffusing the liquid fuel. In particular, it is effective at the start when the liquid fuel is not completely vaporized. The same effect can be exerted in a state where the apparatus is not allowed to stand still or an inclined state. As a device, it can be lightweight and compact, has little danger of explosion, CO, NO
Low toxic exhaust gas such as x. Further, by bonding the ceramic fibers with a binder or the like, a capillary phenomenon acts on the porous body, and the diffusion of fuel is promoted as compared with a porous body not bonded with the binder. Further, by reducing the size of the fuel supply holes, the fuel can be uniformly diffused by uniformly discharging the fuel by uniformly discharging the fuel from all the holes.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing a catalytic combustion device according to the present invention.

FIG. 2 is a schematic configuration diagram showing an example of a fuel supply system using a box on a thin flat plate.

FIG. 3 is a schematic configuration diagram illustrating an example of a fuel supply system using a pipe.

FIG. 4 is a configuration diagram schematically showing a burner type device used as a heat source of a fuel reformer.

FIG. 5 is a configuration diagram schematically showing a device used as a heat source of a conventional fuel reformer.

FIG. 6 shows an example of a fuel reformer incorporating the catalytic fuel device of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Catalyst support layer 2 Fuel diffusion layer 3 Fuel supply system 4 Air 5 Fuel 6 Fuel supply hole (injection hole) 7 Contact part with fuel diffusion layer 8 Fuel supply pipe 9 Air supply system 10 Fuel diffusion space 11 Catalyst combustion part 12 Dioxide Carbon CO ₂ and water H ₂ O 13 Reforming section 14 Reforming catalyst 15 Hydrogen H ₂ and carbon dioxide CO ₂ 16 Fuel and water 17 Vaporizing section

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Claims (8)

[Claims] 1. A catalytic combustion device for use in a fuel reformer that generates hydrogen using hydrocarbons or alcohols as a reforming raw material, comprising a catalyst support layer, a fuel diffusion layer, and a fuel supply system. A catalytic combustion device characterized by the above-mentioned. 2. The catalytic combustion apparatus according to claim 1, wherein said catalyst support layer is made of alumina ceramic fibers. 3. The specific surface area of the alumina ceramic fiber is not less than 10 m ² / g.
A catalytic combustion device according to any of the preceding claims. 4. The catalytic combustion apparatus according to claim 3, wherein 0.1 to 1.0% by weight of platinum is supported on the surface of the alumina ceramic fiber. 5. The catalytic combustion device according to claim 1, wherein the fuel diffusion layer is formed of a porous body in which ceramic fibers are bonded with a binder. 6. The catalytic combustion apparatus according to claim 5, wherein the density of the porous body is 3% by weight or more of the theoretical density. 7. The fuel supply system is in contact with a fuel diffusion layer,
2. The catalytic combustion device according to claim 1, wherein the contact portion has a hole for supplying fuel. 8. The catalytic combustion device according to claim 1, wherein the diameter of the fuel supply hole is 1 mm or less.