JPH08208203A - Fuel reformer - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a fuel reformer in which the device configuration is combined to make a fuel cell power plant compact. [Structure] A raw material gas pipe 9 is arranged in a combustion gas discharge passage in a storage container 4. The raw material gas pipe 9 is provided so as to form a meandering path to increase the heat transfer area. The raw material gas 12 preheated by the raw material gas preheater 2 is introduced into the fuel reformer 1 through the raw material gas inlet 6 and passes through the raw material gas pipe 9 to reform the reforming pipe 3
To the reforming catalyst layer inside.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel reformer for producing a reformed gas containing hydrogen as a main component by a steam reforming reaction using a catalyst by heating a raw material gas in which a hydrocarbon gas is mixed with steam by a combustion gas. More specifically, the present invention relates to a fuel reformer capable of making a fuel cell power generation system compact by combining the functions of a fuel reformer suitable for use in a fuel cell power generation system.

[0002]

2. Description of the Related Art A fuel cell power generation system generally comprises a fuel cell main body, a fuel reformer, a power converter, a controller and many heat exchangers, and is a very complicated system.

FIG. 6 shows the structure of a general fuel reformer in a conventional fuel cell power generation system. The configuration and function of the fuel reformer 1 will be described below.

One or a plurality of reforming tubes 3 filled with a reforming catalyst are erected in a storage container 4 having a heat insulating material 11 of an appropriate thickness on its inner surface, and a burner 5, A raw material gas inlet 6, a reformed gas outlet 7, and a combustion gas outlet 8 are provided, and a raw material gas preheater 2 is provided on the upstream side of the system leading to the raw material gas inlet 6. The raw material gas inlet 6 is connected to the reforming pipe 3 via a raw material gas pipe 9, and the reformed gas outlet 7 is connected to the reforming pipe 3 via a reforming gas pipe 10.

Raw material gas in which steam is mixed with hydrocarbon gas
12 is a raw material gas preheater 2 which is preheated to a proper temperature at which a reforming reaction occurs by using a heating fluid as a reformed gas 13, and a reformer 3 filled with a reforming catalyst from a raw material gas inlet 6 through a raw material gas pipe 9. Be led to. Then, the raw material gas 12 is heated by the combustion gas 14 flowing outside the reforming pipe 3 and the temperature thereof gradually rises, and a reforming reaction occurs due to the action of the reforming catalyst, so that the reformed gas containing hydrogen as a main component. Change to 13. Then, the generated reformed gas 13 flows into the reformed gas pipe 10,
The raw material gas preheater 2 is discharged from the reformed gas outlet 7 to the outside of the device.
After being used as a heating fluid for the fuel cell, it is sent to the fuel cell main body through a carbon monoxide shift converter (not shown).

On the other hand, high temperature combustion gas burned in the burner 5
14 flows down around the reforming pipe 3 in the height direction. that time,
The temperature of the combustion gas 14 gradually decreases by exchanging heat with the raw material gas 6 flowing inside the reformer 3, is discharged from the combustion gas outlet 8 to the outside of the device, and is sent to the next device (not shown).

[0007]

In the fuel cell power generation system having the conventional fuel reformer having the above-mentioned structure and function, the raw material gas is preheated to an appropriate temperature at which the reforming reaction occurs, It is necessary to introduce it into the reforming catalyst layer. If the temperature of the raw material gas introduced into the reforming catalyst layer is lower than the proper temperature at which the reforming reaction occurs, the reforming reaction in the catalyst layer in the low temperature region will be insufficient and the catalyst layer will be ineffective. turn into. On the contrary, heating the temperature of the source gas to a predetermined temperature or higher improves the reforming performance, and thus has various advantages such as shortening the height of the reforming catalyst layer.

The raw material gas preheater 2 is provided for preheating the raw material gas to an appropriate temperature for the above reason, and is an indispensable device, but is required to be downsized. Further, since the raw material gas preheater 2 preheats the raw material gas by using the reformed gas as a high temperature source, the preheating is limited.

The fuel reformer is a device that occupies a large capacity together with the fuel cell main body in the fuel cell plant, and is required to be downsized by improving the efficiency of reforming performance.

An object of the present invention is to provide a fuel reformer which is designed to have a compact fuel cell plant by combining equipment configurations. Another object is to provide a fuel reformer in which the raw material gas is kept at a high temperature to enhance the reforming performance.

[0011]

In order to achieve the above object, the present invention uses a combustion gas discharge passage in a storage container 4 as an exhaust heat recovery area and preheats a source gas in the exhaust heat recovery area. It is characterized in that a tubular heat exchanger is provided.

[0012]

By heating the raw material gas with the combustion gas inside the fuel reformer, part or all of the preheating of the raw material gas can be performed by the fuel reformer, so that the raw material gas preheater can be made compact or It can be unnecessary. Further, by maintaining the temperature of the raw material gas introduced into the reforming catalyst at a higher temperature than in the conventional case, the reforming performance can be significantly improved.

[0013]

EXAMPLE An example of the present invention will be specifically described below with reference to FIG. The same members as those in the conventional example shown in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted. In the present embodiment, as shown in the figure, a heat exchanger in which a raw material gas pipe 9 is arranged in a combustion gas discharge passage in a storage container 4 and a combustion gas 14 is a high heat source and a raw material gas 12 is a low heat source. Are configured. In this embodiment, the raw material gas pipe is provided so as to form a meandering path to increase the heat transfer area. The raw material gas 12 is preheated by the raw material gas preheater 2 and then introduced into the fuel reformer 1 through the raw material gas inlet 6. The combustion gas 14 is further heated through the raw material gas pipe 9 and introduced into the reforming catalyst layer in the reforming pipe 3.

As described above, by providing the function of preheating the raw material gas 12 inside the fuel reformer 1 and combining the reforming function and the raw material gas preheating function, a part of the preheating of the raw material gas 12 or Since the entire process can be performed by the fuel reformer 1, the required capacity of the raw material gas preheater 2 is reduced or unnecessary, and the raw material gas preheater 2 can be made compact or deleted.

Further, since the raw material gas 12 preheated by the raw material gas preheater 2 can be further heated inside the fuel reformer 1 by using the combustion gas 14 having a temperature higher than that of the raw material gas 12 as a heating fluid, the reforming is performed. It is possible to raise the temperature of the raw material gas 12 introduced into the catalyst layer to improve the reforming performance. Therefore, since the length of the reforming catalyst layer can be shortened, the height of the reforming pipe 3 can be shortened, and the fuel reformer 1 can be made compact.

Another embodiment of the present invention will be described with reference to FIG. In FIG. 2, a part different from FIG. 1 will be partially explained. In the embodiment of FIG. 2, the combustion gas discharge passage is extended to the inside of the heat insulating material 11 between the storage container 4 and the reforming pipe 3, and the raw material gas pipe 9 is annularly arranged in the combustion gas discharge passage. The heat exchanger is characterized in that the combustion gas 14 is a high heat source and the source gas 12 is a low heat source. By arranging the source gas pipe 9 in an annular shape, the length of the source gas pipe 9 can be increased, so that the heat transfer area is increased and the source gas 12 can be efficiently heated.

Another embodiment of the present invention will be described with reference to FIGS. 3, 4 and 5. In each figure, a part different from FIG. 1 will be partially explained. The embodiment of FIG. 3 is characterized in that the combustion gas discharge passage in the storage container 4 is filled with the heat transfer promoting member 15. The heat transfer promotion member 15 is filled with alumina balls or the like. By interposing the heat transfer promoting member 15 in the combustion gas discharge passage, the flow velocity of the combustion gas 14 is increased and the degree of turbulence is also increased.
Heat transfer from 14 to the source gas pipe 9 is promoted, and the source gas 12 can be efficiently heated.

The embodiment of FIG. 4 is characterized in that a heat transfer promoting fin 16 is attached to the outer surface of the raw material gas pipe 9.
By attaching the heat transfer promotion fins 16, the raw material gas pipe 9
Since the heat transfer area on the outer surface of the raw material gas is increased, heat transfer from the combustion gas 14 to the raw material gas pipe 9 is promoted, and the raw material gas 12 is efficiently transferred.
Can be heated.

The embodiment shown in FIG. 5 is characterized in that an inlet pipe 17 for the combustion gas 14 is provided outside the source gas pipe 9. By flowing the combustion gas 14 between the raw material gas pipe 9 and the introduction pipe 17, the flow velocity of the combustion gas 14 flowing around the raw material gas pipe 9 is accelerated, and heat transfer from the combustion gas 14 to the raw material gas pipe 9 is promoted. The source gas 12 can be efficiently heated.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and a structure in which the respective embodiments are combined can be adopted. That is, a structure is provided in which a raw material gas tube having the function of a heat transfer tube is provided in the combustion gas passage after heating the reforming tube, and a heat exchanger in which the combustion gas is on the high temperature side and the material gas is on the low temperature side In that case, the above-mentioned object can be achieved.

[0021]

According to the present invention, since the tubular heat exchanger for preheating the raw material gas is provided inside the fuel reformer, the capacity of the raw material gas preheater can be reduced or omitted, and the raw material gas preheating can be performed. The vessel can be compacted or deleted.

Further, since the raw material gas preheater uses the reformed gas as a high heat source, the preheating temperature of the raw material gas is limited,
In the present invention, the raw material gas can be further heated inside the fuel reformer, and the reforming performance can be improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a fuel reformer according to the present invention.

FIG. 2 is a vertical sectional view showing another embodiment of the present invention.

FIG. 3 is a sectional view showing a main part of another embodiment of the present invention.

FIG. 4 is a sectional view showing a main part of another embodiment of the present invention.

FIG. 5 is a sectional view showing an essential part of another embodiment of the present invention.

FIG. 6 is a vertical sectional view showing an example of a conventional fuel reformer.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel reformer, 3 ... Reformer, 4 ... Storage container, 5 ... Burner, 9 ... Raw material gas pipe, 12 ... Raw material gas, 13 ... Reformed gas, 14
... Combustion gas, 15 ... Heat transfer promotion member, 16 ... Heat transfer promotion fin,
17 ... Introduction tube.

Claims (4)

[Claims] 1. One or a plurality of water quality pipes for producing a reformed gas containing hydrogen as a main component by a steam reforming reaction by heating a raw material gas obtained by mixing a hydrocarbon gas and steam, and the reforming pipe. In a fuel reformer having a storage container for storing, a raw material gas pipe for introducing a raw material gas into the reforming pipe, and a burner for generating combustion gas for heating the reforming pipe, The fuel reformer is characterized in that the combustion gas exhaust passage is used as an exhaust heat recovery area, and a tubular heat exchanger for preheating the raw material gas is provided in the exhaust heat recovery area. 2. The fuel reformer according to claim 1, wherein the exhaust heat recovery region is filled with a heat transfer promoting member. 3. The fuel reformer according to claim 1, wherein a heat transfer promoting fin is provided on a surface of the raw material gas pipe. 4. The fuel reformer according to claim 1, further comprising a combustion gas introduction pipe provided outside the raw material gas pipe.