JPH0840702A - Catalytic combustion-type heat exchange-type reformer - Google Patents

Abstract

PURPOSE:To provide a heat exchange-type reformer designed to improve system efficiency by a stock gas is fed and a reformed gas is generated using a reforming catalyst and concurrently, a fuel gas is fed and burned in the presence of a combustion cataluyst and the resultant exhaust gas is discharged via an outlet. CONSTITUTION:A low-caloric gas such as a mixed gas of anode exhaust gas and cathode exhaust gas from a fuel cell is fed via a fuel gas feed port 23 and burned in the presence of a combustion catalyst 30 packed to a perforated plate 25, and the resultant combustion gas heats a 2nd pipe group 22, a 3rd pipe assembly 20 and a 1st pipe group 21, and is then discharged via an exhaust gas discharge port 24. During the process, the flow pattern of the combustion gas is trimmed by incombustible particles 31 such as of Al2O3 packed under the perforated plate 25. Concurrently, a city gas as stock gas is fed together with steam via a relevant feed port 16 and then subjected to reforming reaction using a reforming catalyst 23 heated in the 1st pipe group 21, the 3nd pipe assemmbly 20 and the 2nd pipe group 22, generating a reformed gas predominant in H2, which is then discharged via a relevant port 17, thus obtaining the objective reformed gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reformer for reforming a raw material gas into a gas containing hydrogen and supplying it to a fuel cell in a fuel cell power generation system, and more particularly to a catalytic combustion type heat which can use a low calorie fuel gas. The present invention relates to an exchange type reformer.

[0002]

2. Description of the Related Art Molten carbonate fuel cells have characteristics that conventional power generators do not have, such as high efficiency and little influence on the environment, and are attracting attention as a power generation system following hydropower, thermal power, and nuclear power. Are gathering. FIG. 5 shows a basic flow chart of a molten carbonate fuel cell, which comprises a reformer 1 for converting a raw material gas into a reformed gas containing hydrogen as a main component, and a fuel cell 2 for generating electricity by the reformed gas. The reformer 1 comprises a reforming chamber 1a for converting the raw material gas into a reforming gas by a reforming catalyst and a combustion chamber 1b for heating the reforming chamber 1a, and the fuel cell 2 comprises an anode 2a and a cathode 2b. There is.

In the operation, first, steam is added to city gas as a raw material gas, the steam is introduced into the reforming chamber 1a, and it is converted into a reformed gas mainly containing hydrogen by a reforming catalyst and heating. 2a. Hydrogen is consumed by power generation on the anode side of the battery. On the other hand, in the combustion chamber 1b of the reformer 1, the unreacted hydrogen that has not been consumed by the anode 2a is burned as the main fuel, and the combustion heat is used as a heat source for the reforming reaction. The carbon dioxide in the combustion exhaust gas is supplied to the cathode 2b as a carbon dioxide raw material on the cathode side of the battery. As described above, the anode exhaust gas used as the fuel of the reformer 1 is a low-calorie gas, which is mainly composed of carbon dioxide and water vapor and has a low hydrogen content.

The reformer is roughly classified into a cylindrical burner combustion type and a plate type catalytic combustion type. FIG. 6 shows a typical configuration of a cylindrical burner combustion reformer. The combustion gas burned in the burner 1 passes through the route indicated by the one-dot chain line arrow,
After the second reforming chamber 3 and the first reforming chamber 2 are heated, they are discharged as exhaust gas. Raw gas such as city gas and steam pass through the first reforming chamber 2 filled with the reforming catalyst as shown by an arrow A,
Further, it passes through the second reforming chamber 3 and is converted into a reformed gas mainly composed of hydrogen gas and is discharged as shown by an arrow B.

FIG. 7 shows a typical structure of a plate type catalytic combustion reformer. The reforming chamber 4 filled with the reforming catalyst and the combustion chamber 5 filled with the combustion catalyst are partitioned by the heat transfer partition wall 6, and the reforming chamber 4 is supplied with the raw material gas and the steam and is mainly composed of hydrogen gas. It is reformed into quality gas. Fuel gas and air are supplied to the combustion chamber 5, burned to heat the reforming chamber 4, and then discharged as combustion exhaust gas.

[0006]

When a low calorie gas such as anode exhaust gas is used as fuel gas in a burner combustion type reformer, ignition is not stable. In order to keep the ignition stable even during normal operation, special measures are required for the burner straw. An auxiliary combustion device is also required. Due to the structure of the plate type reformer, the distribution of fuel gas and air is non-uniform and the reaction may not be sufficient, or the thermal stress may become high and the combustion temperature may have to be limited. Rate and combustion efficiency may not be obtained. Also, there is a limit to the working pressure due to the structure.

The present invention has been made in view of the above-mentioned problems, and it is possible to stably generate a reformed gas with a low calorie fuel gas by using a catalytic combustion system, and to provide a structure with less thermal stress. It is an object of the present invention to provide a catalytic combustion type heat exchange reformer capable of increasing the pressure of reformed gas by performing a reforming reaction in a pipe.

[0008]

In order to achieve the above object, a horizontally provided tube plate, a cylindrical cylinder coupled to the tube plate at the upper end and closed at the lower end, and an upper end provided in the cylinder Is fixed to the lower surface of the tube sheet, the lower end of which is located at a predetermined height from the lower end of the body and is in contact with the body in the width direction, and the partition plate on the lower surface of the tube sheet and which is sandwiched between the raw materials. A first header having a gas supply port and a second header having a reformed gas discharge port; a third header provided at a position lower than the lower end of the partition plate in the barrel; and an upper wall of the barrel and Exhaust gas discharge port provided in the lower portion of the first pipe header, fuel gas supply port provided in the upper wall of the body and below the second pipe header, and first pipe header and third pipe penetrating the tube plate. A first tube group communicating with the second tube group and a second tube group penetrating the tube plate and communicating with the second tube group and the third tube group; The combustion catalyst is filled to a constant height, and the reforming catalyst is filled in the tubes of the first tube group and the second tube group to a height substantially equal to a predetermined height in the barrel and in the third header. The raw material gas is supplied from the raw material gas supply port to generate the reformed gas by the reforming catalyst, the fuel gas is supplied from the fuel gas supply port and burned by the combustion catalyst, and the exhaust gas is discharged from the exhaust gas discharge port. It was done.

Further, the first pipe group and the second pipe group are connected in a U shape in place of the third pipe header.

Further, a porous plate is provided at a predetermined height from the lower end of the partition plate, and non-combustible particles for rectifying the combustion gas are filled below the porous plate instead of the combustion catalyst.

[0011]

Operation: The fuel gas supplied from the fuel gas supply port burns through the combustion catalyst to heat the second tube group and bring it to the third tube group,
Further, after heating the first tube group, it is discharged from the exhaust gas discharge port. On the other hand, the raw material gas supplied from the raw material supply port is converted into the reformed gas by the reforming reaction as it enters the first tube group from the first header and is heated and passes through the reforming catalyst. Further, the conversion into the reformed gas proceeds by passing through the third pipe group and the second pipe group, and the reformed gas is supplied to the fuel cell from the reformed gas discharge port through the second pipe group. In this way, since combustion is performed using the combustion catalyst, it is possible to stably burn even low-calorie fuel gas such as anode exhaust gas of a fuel cell. Further, the reformed gas passes through the first to third tube bundles and the first and second tube groups, but since these are mainly composed of tubes, it is possible to easily increase the pressure resistance, so that the high pressure It becomes possible to generate a reformed gas. Structurally, the partition plate and the first and second tube groups can be freely thermally expanded only by fixing the upper end to the tube plate, so that the generation of thermal stress is small.

Even if the first tube group and the second tube group are directly connected to each other in a U-shape instead of the third header, the reforming efficiency does not change, the structure is simple, and the thermal stress is reduced. .

[0013] A third pipe arrangement or a first pipe group and a second pipe under the trunk
Where there is a U-shaped part that connects to the tube group, combustion efficiency is not very good despite the large amount of combustion catalyst clogging, so this part is filled with non-combustible particles that improve rectification of the combustion gas instead of the combustion catalyst. By doing so, it is possible to improve the economic efficiency without significantly reducing the combustion efficiency.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. 1 is a vertical sectional view of the first embodiment, FIG. 2 is a view taken along the line XX of FIG. 1, and FIG. 3 is a view taken along the line YY of FIG. Reference numeral 11 denotes a tube plate through which first and second tube groups 21 and 22 to be described later penetrate. Reference numeral 12 denotes a cylinder, which is a cylindrical shape with the tube sheet 11 at the top and the lower portion closed, and the upper end is welded to the lower surface of the tube sheet 11 through the center of the cylindrical shaft. Partition plate 13 at a predetermined height from 28
Is provided. The predetermined height is determined in consideration of the third header 20 and the flow path of combustion gas, which will be described later. On the tube plate 11, the first plate header 14 is sandwiched with the partition plate 13 on the lower surface interposed.
And a second header 15 is provided. The first header 14 and the second header 15 are composed of a double ring, and the partition plate 13
Are separated by a blind flange 18 in the position. A raw material gas supply port 16 is provided in the first header 14 and a reformed gas discharge port 17 is provided in the second header 14, and the openings 19 other than these openings 16 and 17 are covered with a cover 19.

A third portion is provided between the lower end 27 of the partition plate and the lower end 28 of the body.
A pipe header 20 is provided, the first pipe group 21 communicates with the first pipe header 14, and the second pipe group 22 communicates with the second pipe header 15.
Is in communication with Since the first and second tube groups 21 and 22 are welded to the tube sheet 11 and configured to support the third header 20, the thermal expansion can be freely performed and the generation of thermal stress can be reduced.
A fuel gas supply port 23 is provided on the upper wall of the body 12 on the second pipe group 22 side, and an exhaust gas discharge port 24 on the first pipe group 21 side.
Is provided. A perforated plate 25 is provided over the entire surface of the barrel 12 at a level slightly above the lower end 27 of the partition plate, and is supported by the first and second tube groups 21, 22 and the partition plate 13. The inner surface of the body 12 and the lower surface of the tube sheet 11 are covered with a refractory material 26.

A combustion catalyst 30 is provided from a predetermined level below the fuel gas supply port 23 and the exhaust gas discharge port 24 to the perforated plate 25.
The non-combustible particles 31 made of non-combustible material such as alumina or ceramics are filled between the perforated plate 25 and the body lower end 28. Further, a reforming catalyst 32 is filled in the first and second tube groups 21, 22 and the third header 20 below the level substantially equal to the predetermined level. The thickness filled with the combustion catalyst 30 is the first and second tube groups 21, 22.
It is determined in consideration of the reforming reaction.

Next, the operation will be described. A premixed gas of anode exhaust gas and cathode exhaust gas from the fuel cell is supplied from the fuel gas supply port 23. These low calorie gases are combusted by the combustion catalyst 30, and the combustion gas is the second tube group 2
2, the third pipe header 20, and the first pipe group 21 are heated and discharged from the exhaust gas discharge port 24. At this time, the noncombustible particles 31 rectify the combustion gas. On the other hand, city gas is supplied together with water vapor as a raw material gas from the raw material gas supply port 16, and is reformed by the reforming catalyst 32 heated in the first tube group 21, the third tube group 20, and the second tube group 22. Then, a reformed gas mainly containing hydrogen is generated and discharged from the reformed gas discharge port 17.

As described above, by using the combustion catalyst 30, even a low calorie gas such as the anode exhaust gas and the cathode exhaust gas is sufficiently combusted, and the raw material gas supplies a sufficient amount of heat for the reforming reaction by the reforming catalyst 32. can do. Further, the reformed gas is supplied to the first, second pipes 14, 15, and
Since the pipes 20 and the first and second pipe groups 21 and 22 pass through a structure mainly composed of pipes, the pressure can be easily increased structurally. In addition, the first and second tube groups 21 and 22, the partition plate 1
Since 3 is supported by the tube sheet 11 at one place, thermal expansion can be freely performed and thermal stress is less likely to occur.

FIG. 4 shows a second embodiment. In this embodiment, instead of the third header 20 of the first embodiment shown above, the first,
The lower ends of the two tube groups 21 and 22 are directly connected to each other in a U shape, and the other points are the same as in the first embodiment. Compared to the first embodiment,
The performance is the same, but the structure is simple.

In the first and second embodiments described above, the perforated plate 25 is provided and the non-combustible particles 31 are filled under the perforated plate 25.
The combustion catalyst 30 may be filled in all without providing 5. Also,
Although the partition plate 13 is a flat plate, the generation of thermal stress can be reduced by using a corrugated plate or a diaphragm. Further, although the anode exhaust gas and the cathode exhaust gas are used as the fuel gas, only the anode exhaust gas may be used.

[0021]

As is apparent from the above explanation,
The present invention enables stable combustion of low calorie gas such as anode exhaust gas by using a combustion catalyst. Further, the pressure can be easily increased by passing the reformed gas through a structure mainly composed of a pipe. Further, since the portion where thermal stress is easily generated is supported at one place, the generation of thermal stress can be reduced. As a result, the exhaust gas of the battery can be effectively used in the fuel cell power generation system, and the system pressure is increased and the system efficiency is improved. Further, since the thermal stress is small, structural reliability is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a configuration of a first embodiment.

FIG. 2 is a view on arrow XX in FIG.

FIG. 3 is a view taken along the line YY of FIG.

FIG. 4 is a vertical sectional view showing the configuration of the second embodiment.

FIG. 5 is a basic flow chart of a molten carbonate fuel cell.

FIG. 6 is a diagram showing a typical configuration of a cylindrical burner combustion reformer.

FIG. 7 is a diagram showing a typical configuration of a plate-type catalytic combustion reformer.

[Explanation of symbols]

 11 Tube Plate 12 Body 13 Partition Plate 14 First Pipe Alignment 15 Second Pipe Alignment 16 Raw Material Gas Supply Port 17 Reformed Gas Discharge Port 18 Blind Flange 19 Cover 20 Third Pipe Alignment 21 First Pipe Group 22 Second Pipe Group 23 Fuel gas supply port 24 Exhaust gas discharge port 25 Perforated plate 26 Refractory material 27 Lower end of partition plate 28 Lower end of body 30 Combustion catalyst 31 Non-combustible particles 32 Reforming catalyst

Claims (3)

[Claims] 1. A horizontally-provided tube sheet, a cylindrical body that is connected to the tube sheet at the upper end and closed at the lower end, and a tubular body that is provided in the body and has the upper end fixed to the lower surface of the tube sheet and the lower end. A first pipe header having a raw material gas supply port provided between the partition plate which is at a predetermined height from the lower end and is in contact with the body in the width direction, and the partition plate on the lower surface of the pipe plate and which is on the lower side. A second header having a quality gas discharge port, a third header provided in the cylinder at a position lower than the lower end of the partition plate, and an exhaust gas provided on the upper wall of the cylinder and below the first cylinder A discharge port, a fuel gas supply port provided on the upper wall of the body and below the second pipe header, a first pipe group penetrating the pipe plate and communicating the first pipe header and the third pipe header, A second pipe group penetrating the plate and connecting the second pipe header and the third pipe header to each other, the combustion catalyst being filled to a predetermined height in the barrel, and the first pipe. A reforming catalyst is filled in the tubes of the second tube group and the second tube group to a height substantially equal to a predetermined height in the barrel and in the third header, and a raw material gas is supplied from the raw material gas supply port to reform the gas. A reformed gas is generated by a catalyst, a fuel gas is supplied from the fuel gas supply port, burned by a combustion catalyst, and exhaust gas is discharged from the exhaust gas discharge port. Pawn. 2. The catalytic combustion type heat exchange reformer according to claim 1, wherein the first tube group and the second tube group are connected in a U-shape instead of the third header. . 3. A partition plate is provided with a perforated plate at a position at a predetermined height from the lower end, and below the perforated plate, non-combustible particles for rectifying the combustion gas are filled instead of the combustion catalyst. The catalytic combustion type heat exchange reformer according to claim 1 or 2.