JPS61171530A - Fuel reforming device - Google Patents

Abstract

PURPOSE:To impart good temp. distribution to a catalyst bed, by embedding an oxidizing agent introducing pipe in a catalyst packed bed containing a fuel catalyst and providing through-holes for flowing out an oxidizing agent to the pipe wall of said introducing pipe while allowing fuel to pass through the catalyst packed bed. CONSTITUTION:An oxidizing agent 16 is injected from a large number of small holes 13 provided to an introducing pipe 6 toward the outside under equal pressure to generate combustion reaction in the whole of the packed bed of a combustion catalyst 12 while supplied to fuel 15 flowing through the packed bed of the combustion catalyst 12 in a dispersed state. The gas after combustion reaction receives heat generated by combustion reaction while passes through the reforming catalyst 14 allowed to pack the gap between a partition pipe 5 and a container 2. Reforming reaction (endothermic reaction) based on the residual fuel and steam generated by combustion reaction is generated and reformed gas 17 is discharged out of a fuel reforming device 1 from a gas outlet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a fuel reformer, and particularly to a fuel reformer suitable for use in a fuel cell power generation system and the like.

[Background of the invention]

Conventionally, fuel reformers are known that include a process of causing a combustion reaction between a fuel such as a hydrocarbon and an oxidizer using a combustion catalyst.
For example, in the US literature (1978, Catalytica Associates
He is familiar with Overview of Tsuyuel Processing Chikunoroshis Fortsuyuel Power Generation) published by Co., Ltd.

On pages 5 to 37 of the above document, a reforming catalyst layer is placed immediately after the combustion catalyst layer so that a fuel such as a hydrocarbon is caused to undergo a combustion reaction with an oxidizer using a combustion catalyst, and the generated reaction heat can be utilized. A fuel reformer is described. This technology constitutes the basic structure of a so-called autothermal reformer. One problem with this autothermal reformer is the temperature distribution of the combustion catalyst layer or the reforming catalyst layer, and another problem is the difference in the optimum operating temperature or durability temperature of the combustion catalyst and the reforming catalyst. be. These two problems have a significant effect on the lifetime of both catalysts, and therefore become constraints on the design of the autothermal reformer. Regarding the latter problem, at present, a PT or Pd type catalyst is used as a combustion catalyst at a temperature of about 1,000°C, and a Ni type catalyst is used as a reforming catalyst at a temperature of about 800°C.

Of the two problems mentioned above, the problem that the combustion catalyst and the reforming catalyst have different optimal operating temperatures and durability temperatures cannot be fundamentally solved unless a new catalyst is developed.

Regarding the other problem of the above two problems, that is, the temperature distribution, the reason why the inappropriate temperature distribution is formed is as follows.

Because the mixture of fuel and oxidizer is directly fed into the combustion catalyst layer or reforming catalyst layer in a so-called extrusion flow, many reactions occur near the inlet of the catalyst layer, resulting in uneven reaction progress. An inappropriate temperature distribution is formed in the catalyst layer due to this.

It is thought that this problem can be solved by improving the flow, diffusion, and mixing conditions of the reactants.It is thought that the problem can be solved by improving the flow, diffusion, and mixing conditions of the reactants. .

[Purpose of the invention]

An object of the present invention is to provide a fuel reformer that can achieve good temperature distribution in the catalyst layer by dispersing and supplying an oxidizing agent or fuel to the catalyst layer.

[Summary of the invention]

Typically, a fuel reformer used in a fuel cell power generation system is a tubular reactor that can be operated continuously.

A tubular reactor has a single-tube type or a multi-tube type configuration in which a plurality of single tubes are grouped together.The tubes are filled with a catalyst, reactants are poured into one tube as an inlet, and produced substances are discharged from the other outlet.

Next, the basic principle of the present invention will be explained.

The present invention focuses on the fact that in a fuel reformer in a fuel cell power generation system, the combustion reaction is a reaction between two types of fluids: fuel and oxidizer, and the reforming reaction is mainly a reaction between two types of fluids: fuel and steam. For example, one species. □I71ゎu, yo1,
□, yo□. □ An inlet tube having a diameter of 1" is provided, another substance B is flowed into the inlet tube having the above-mentioned holes, and the substance B is blown out from the holes to react with the substance A. This causes the substance B to react with the substance A.

The reactants A and B are distributed and supplied to the catalyst layer in the tube axis direction to avoid inappropriate temperature distribution in the catalyst layer.

In order to achieve the above object based on [11] above, the fuel reformer according to the present invention is a fuel reformer that includes a process of causing a fuel such as a hydrocarbon to undergo a combustion reaction with an oxidizer using a combustion catalyst. An oxidizing agent introduction pipe is buried in the catalyst packed bed containing the fuel catalyst, a through hole is provided in the wall of the introduction pipe for the oxidizing agent to flow out, and the fuel is introduced into the catalyst packed bed. It is characterized by being configured so that it can pass through.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows a cross-sectional view of a single-tube fuel reformer 1. As shown in FIG. The fuel reformer 1 has a container 2 and a cap 3 connected together by bolts 4 to form an external appearance.

The cap 3 has a partition tube 5, and an introduction tube 6 that penetrates and is fixed to the cap 3 is provided within the partition tube 5. A lower fuel inlet, an oxidizer port 8 and a catalyst insertion port 9 are provided in the center of the cap 3, several catalyst insertion ports 10 are provided in the peripheral portion thereof, and a gas outlet 11 is provided in the side portion. The oxidizing agent port 9 is the inlet of the inlet pipe 6. The partition pipe 5 and the introduction pipe 6 extend a little before reaching the bottom of the container 2, and the combustion catalyst 12 inserted through the catalyst insertion port 9 is inserted into the gap between the partition pipe 5 and the introduction pipe 6 at the height of the container 2. It is filled to a certain extent. The introduction pipe 6 is provided with a large number of small holes 13 in a portion surrounded by the combustion catalyst 12, and the end of the introduction pipe 6 is closed.

The gap between the partition pipe 5 and the container 2 is filled with a reforming catalyst 14 inserted through the catalyst insertion port 10 to about the height of the container 2.

The operation of the fuel reformer 1 configured as above will be explained next.

Preheated fuel 15 and oxidizer 16 flow into fuel reformer 1 from the fuel input lower and oxidizer inlet 8, respectively. The fuel 15 that has flowed into the fuel reformer 1 passes through a packed bed of combustion catalysts 12 . On the other hand, the oxidizer 16 that has flowed into the fuel reformer 1 from the oxidizer inlet 8 flows through the introduction pipe 6, but is discharged into the combustion catalyst 12 from the small hole 13 midway through the introduction pipe 6.

As described above, the end of the introduction tube 6 is closed, and the oxidizing agent 16 is ejected outward from the large number of small holes 13 provided in the introduction tube 6 at equal pressure according to Pascal's principle. Thereby, the oxidizing agent 16 is distributed and supplied to the fuel 15 flowing in the packed bed of the combustion catalyst 12, and a combustion reaction (exothermic reaction) is caused in the entire packed bed of the combustion catalyst 12. The gas that has completed the combustion reaction receives and absorbs the heat generated by the combustion reaction while passing through the reforming catalyst 14 filled in the gap between the partition pipe 5 and the container 2, and mainly uses the remaining fuel and the steam generated by the combustion reaction. A reforming reaction (endothermic reaction) occurs, and the reformed gas 17 is released from the gas outlet 11 to the outside of the fuel reformer 1.

According to this embodiment, the combustion reaction can be dispersed throughout the combustion catalyst packed bed by the introduction pipe having a large number of small holes provided in the center of the fuel reformer, thereby preventing a local temperature rise of the combustion catalyst. can. As a result, the life of the combustion catalyst is improved, and the temperature distribution of the combustion catalyst packed layer is made uniform, thereby reducing the thermal reaction force of the entire fuel reformer.

FIG. 2 shows another embodiment of the present invention, and the parts that are different from those in FIG. 1 will be partially taken up and explained. This embodiment is characterized in that several recycle pipes 18 are provided near the cap 3 where the partition pipe 5 does not come into contact with the catalyst.

This recycle pipe 18 connects the upper space in the partition pipe 5, that is, the space above the packed bed of the combustion catalyst 12, and the space above the packed bed of the reforming catalyst device 4. in this case,
The recycle pipe 18 is limited to the one shown in FIG. 2, and it is sufficient if it has an ejector structure.

To explain the operation, the fuel 15 that entered the fuel reformer 1 from the fuel input lower and the oxidizer 16 that entered the fuel reformer 1 from the oxidizer population 8 undergo a combustion reaction in the packed bed of the combustion catalyst 12. However, the gas after the combustion reaction further undergoes a reforming reaction in the packed bed of the reforming catalyst 14 to become a hydrogen-rich reformed gas 17, but some of this reformed gas 17
9 is supplied to the upper part of the packed bed of the combustion catalyst 12 through the recycle pipe 18, and the combustion catalyst 1 is supplied as a mixed gas with the fuel 15.
2.

According to this embodiment, in addition to the effects of the embodiment shown in FIG. 1, since fuel containing hydrogen is fed to the combustion catalyst, the combustion temperature can be suppressed and the life of the combustion catalyst can be further improved. Moreover, as the flow rate of fuel and oxidizer increases and the amount of combustion reaction increases, more hydrogen-rich reformed gas is also sent to the combustion catalyst to be recycled. This has the effect of preventing the temperature of the combustion catalyst from rising.

FIG. 3 shows another embodiment of the present invention, and the parts that are different from those in FIG. 1 will be partially taken up and explained. This embodiment is characterized in that a plurality of small holes 20 are provided in a portion of the partition tube 5 near the bottom of the container 2. A portion of the combustion gas flows into the packed bed of the reforming catalyst 14 through these small holes 20 .

Heat is applied directly to the reforming catalyst 14 and the gas surrounding the reforming catalyst 14.

According to this embodiment, in addition to the effects of the embodiment shown in FIG. 1, since some of the heat of the combustion gas is directly applied to the reforming reaction, there is an effect that the thermal efficiency of the fuel reformer is improved.

FIG. 4 shows another example of this example.
This is a combination of the features of Figures 2 and 3, and the reformed gas 1
The configuration, operation, and effects of this embodiment are shown in Figures 2 and 3, in which recycling within the fuel reforming 1Ihl and a portion of the heat of the combustion gas are directly contributed to the reforming reaction. The same applies to the case of

Another embodiment of the present invention is shown in FIG. 5, which is a sectional view of a single-tube fuel reformer 1'. The fuel reformer 1' has a structure in which a container 2' and a cap 3' are connected by bolts 4. A fuel inlet pipe 7 is provided in the center of the cap 3', an introduction pipe 6 is provided passing through the fuel inlet pipe 7 and penetrating the pipe wall, and the open end of the introduction pipe 6 is provided with an oxidizing agent. It has a population of 8. Several catalyst insertion ports 9 are provided around the cap 3. At the end of the container 2, there is a gas outlet 11 holding a catalyst support network 21.
is provided. Insert the reforming catalyst 14 into the container 2 through the catalyst insertion port 9 so that it occupies approximately half the volume of the container 2'.Next, similarly insert the combustion catalyst 12 into the container 2 through the catalyst insertion port 9. Then, fill the container 2' to about the height.

At this time, the introduction pipe 6 is inserted into the center of the container 2' over the entire packed bed of the combustion catalyst 12. In addition, the introduction pipe 6 has many small holes 1 in the part surrounded by the combustion catalyst 12.
3, and the end of the introduction tube is closed. The structure of the fuel reformer 1' is as described above, and its operation will be explained next.

Preheated fuel 15 and oxidizer 16 flow into the fuel reformer 1' from the fuel input lower and oxidizer inlet 8, respectively. The fuel 15 that has entered the fuel reformer 1' passes through a packed bed of combustion catalysts 12. On the other hand, the oxidizer 16 flows through the introduction pipe d, but the oxidizer 16 passes through the combustion catalyst 12 from the small hole 13 during its passage.
is released into the filled container. Thereby, the oxidizing agent 16 is distributed and supplied to the fuel 15 flowing in the packed bed of the combustion catalyst 12, and a combustion reaction (exothermic reaction) is caused in the entire packed bed of the combustion catalyst 12. The gas that has completed the combustion reaction passes through the packed bed of the reforming catalyst 14, and consumes the heat of the combustion gas whose temperature has been raised by the combustion reaction to cause a reforming reaction (endothermic reaction), resulting in reforming. The gas 17 is released from the gas outlet 11 to the outside of the fuel reformer 1 .

According to this embodiment, the unifying agent can be distributed and supplied to the entire packed bed of the combustion catalyst using the introduction pipe provided in the combustion catalyst.
This has the effect of preventing local temperature increases in the combustion catalyst, extending the life of the combustion catalyst, and alleviating thermal stress in the entire fuel reformer.
Moreover, since it has a simple structure, it has the effect of improving productivity and economic efficiency.

In each of the embodiments of the present invention shown above, it is also possible to mix a combustion catalyst and a reforming catalyst, and it is highly likely that this will be implemented as new catalysts are developed in the future. , and also disperses and supplies 1 oxidizer in the combustion catalyst 6
Other than that, it is easily understood from the present invention that the fuel reformer may be constructed such that the fuel 1 is supplied in a distributed manner through the introduction pipe 11, or an introduction pipe is also provided in the reforming catalyst to supply fuel or steam in a distributed manner. In addition, possible materials for the introduction tube include porous ceramics in addition to heat-resistant SUS material.

〔Effect of the invention〕

According to the present invention, since the oxidizing agent or fuel can be distributed and supplied to the catalyst layer, it is possible to realize a good temperature distribution in the catalyst layer.

[Brief explanation of the drawing]

1.2, 3, and 4.5 are cross-sectional views showing embodiments of the present invention, respectively. 1.1'...Fuel reformer, 6...Introduction pipe, 12...
-Fuel catalyst, 13...Small hole, 14...Reforming catalyst.

Claims (1)

[Claims] 1. In a fuel reformer that includes a process of causing a fuel such as a hydrocarbon to undergo a combustion reaction with an oxidizer using a combustion catalyst, an oxidizer is contained in a catalyst packed bed containing the fuel catalyst. An inlet pipe is buried, a through hole is provided in the wall of the inlet pipe for the oxidant to flow out,
A fuel reformer characterized in that the fuel reformer is configured to allow fuel to pass through the catalyst packed bed. 2. The catalyst packed bed is provided with a reforming catalyst bed on its downstream side, and a part of the reformed gas that has passed through the reforming catalyst bed is refluxed to the upstream side of the catalyst packed bed. 2. The fuel reformer according to claim 1, further comprising a passage for causing the fuel to deteriorate.