JP2002362901A - Reforming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a reforming apparatus compact by housing a required quantity of a catalyst in a small space. SOLUTION: In the reforming apparatus having a double tube formed by arranging an inside cylindrical tube 11 and an outside cylindrical tube 12 having different diameter from each other concentrically and for reforming a gaseous starting material by introducing the heating gas into the inside of the inside cylindrical tube and heating the inside surface, mounting the reforming catalyst 14 in the gap between the inside cylindrical tube and the outside cylindrical tube, passing the gaseous starting material 15 through the gap and using the heat supplied from a heating gas through the inside surface of the inside cylindrical tube, a spiral fin 13 having a height equivalent to the gap of the double tube is provided on the outside surface of the inside cylindrical tube 11 facing the outside cylindrical tube 12 side, the reforming catalyst 14 is provided and filled in the gap of the spiral fin 13 and the gaseous starting material is passed through the gap of the spiral fin 13 along a flow passage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reformer used for producing fuel gas for a fuel cell power generator.

[0002]

2. Description of the Related Art As a conventional fuel reformer, for example, the one shown in FIG. 5 is known. Reference numeral 1 in the drawing denotes an inner cylindrical tube having a smooth surface, and an outer cylindrical tube 2 having a diameter different from that of the inner cylindrical tube 1 is arranged concentrically outside the inner cylindrical tube 1. A granular catalyst 3 is filled between the inner cylindrical tube 1 and the outer cylindrical tube 2. Although not shown, a burner is arranged inside the inner cylindrical tube 1.

[0003] While the inner surface of the inner cylindrical tube 1 is heated by a heating gas 4 from a burner, a raw material gas 5 flows into a region filled with the granular catalyst 3. The heat energy from the heating gas 4 is transferred from the inner cylindrical tube 1 to the granular catalyst 3 by the contact between the granular catalysts 3 and the raw material gas 5 flowing into the granular catalyst 3 is formed between the catalysts and the catalyst and the inner cylindrical tube. 1 The air is supplied in the direction of the outer cylindrical tube 2 by forced convection heat conduction that flows through the outer wall gap and transfers heat. As a result, the inflowing raw material gas 5 is converted into the reformed gas 6.

[0004]

However, in the conventional reforming apparatus, the heat transfer rate from the heated inner cylindrical tube 1 to the granular catalyst 3 is poor, and if the thickness of the catalyst layer is increased, the inner cylindrical tube 1 cannot be heated. Sufficient heat cannot be supplied to the granular catalyst 3 separated from the outer wall surface, and the reforming rate of the raw material gas 5 passing through that portion decreases.

In order to supply heat to the granular catalyst separated from the outer wall surface of the inner cylindrical tube 1, even if the heating gas temperature is increased to increase the amount of heat supplied from the heated gas to the inner cylindrical tube 1, The granular catalyst 3 near the outer wall surface of the tube 1 deteriorates beyond the endurance temperature (for example, 800 ° C.).

Further, even if an attempt is made to increase the forced convection transfer rate of the gas and increase the inter-catalyst heat transfer to increase the thickness of the catalyst layer by increasing the gas flow rate in the granular catalyst, the amount of the catalyst becomes insufficient with respect to the gas flow rate. Thus, unreformed gas passes through the catalyst.

For this reason, in the conventional reformer, when an increase in the reformed gas (= an increase in the amount of the reforming catalyst) is planned, the catalyst layer between the inner cylindrical tube 1 and the outer cylindrical tube 2 is required. Since the thickness cannot be increased, the axial distance of the cylindrical tube is increased, or the diameter of the cylindrical tube is increased, and the granular catalyst 3 of the inner cylindrical tube 1 is formed.
There is no other way but to increase the area in contact with the surface, and there is a problem that the size of the reformer increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and a spiral fin having a height equivalent to the gap of a double pipe is provided on an outer wall surface facing an outer cylindrical pipe side of an inner cylindrical pipe. By providing a structure in which the catalyst is filled between the fins and the raw material gas flows along the flow path between the spiral fins, a required amount of the catalyst can be stored in a small space, and a compact reformer with a spiral fin can be provided. Aim.

[0009]

According to the present invention, there is provided a double pipe in which an inner cylindrical pipe and an outer cylindrical pipe having different diameters are arranged concentrically. Is heated, and a reforming catalyst is installed in the gap between the inner cylindrical pipe and the outer cylindrical pipe, and the raw material gas flows through the gap, and the reforming is performed by heat supplied from the heated gas through the inner surface of the inner cylindrical pipe. In the reformer to be performed, spiral fins having a height equivalent to the gap between the double tubes are provided on the outer wall surface facing the outer cylindrical tube side of the inner cylindrical tube, and a reforming catalyst is filled between the spiral fins, and the raw material gas is filled. In the flow path between the spiral fins.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

In the present invention, it is preferable that one or more spiral fins are provided and one or more gas channels are provided.
Further, it is preferable to gradually increase the distance between the fins from the gas inlet side to the gas outlet side. Here, the reason why one or more spiral fins are provided is to arbitrarily adjust the cross-sectional area of the source gas flow path formed by the spiral fin or the like by the fin pitch and the number of flow paths. That is,
The ability to arbitrarily adjust the cross-sectional area of the source gas flow passage allows an arbitrary gas flow rate to be set for a target reformed gas generation amount, that is, a predetermined catalyst amount. Therefore, the gas flow rate can be increased to increase the forced convection transmissivity between the catalysts to the maximum pressure loss that the system can tolerate, the reforming catalyst separated from the inner cylindrical tube can be heated, and the thickness of the catalyst layer can be increased. As a result, even if the temperature of the gas for heating the inner cylindrical tube is increased, it is possible to prevent the reforming catalyst adjacent to the outer wall surface of the inner cylindrical tube from being heated to the endurance temperature of the catalyst or higher. Further, as the heating gas temperature increases, the amount of air supplied to the heating gas can be reduced, and the blowing power and the like can be reduced.

On the other hand, it is desirable to gradually increase the distance between the fins from the gas inlet side to the gas outlet side because the catalyst closer to the outer cylindrical tube is more heat than the catalyst closer to the inner cylindrical tube. Is not sufficiently transmitted, so that the heat transfer coefficient into the catalyst is increased by increasing the flow rate of the raw material gas near the gas inlet side.

In the present invention, it is preferable that a plurality of notches are provided from the outer peripheral edge of the spiral fin toward the center axis of the inner cylindrical tube. In other words, in the spiral fin, the temperature is high at the root and the temperature is low at the tip, so that stress is generated due to a difference in thermal elongation between the root and the tip, and the spiral fin may be broken depending on operating conditions. . However, by providing the cut-out portion in the spiral fin, the generated stress can be separated to alleviate the stress, thereby preventing the fin from being damaged or deformed.

1) Damage and powdering due to contact between catalysts, which are observed in a granular catalyst or the like, can be avoided. 2) By selecting the density of the porous body, the heat from the outer wall surface of the inner cylindrical tube and the fin surface is delivered to the inside of the porous body as radiant heat transfer, so that the catalyst can be uniformly heated and the catalyst layer can be heated. The thickness can be increased.

3) Since the heat transfer coefficient between the porous body and the raw material gas is higher than the heat transfer between the granular catalyst and the raw material gas, the catalyst temperature can be further uniformed and the thickness of the catalyst layer can be increased.

4) Since the surface area per volume is larger than that of the granular catalyst, the reforming performance per volume is higher than that of the granular catalyst, and the catalyst volume of the same reforming catalyst performance can be reduced, and the reforming tube can be made compact. can do.

5) Since the weight of the catalyst per volume is smaller, the weight of the apparatus can be reduced.

In the porous porous body, it is preferable that the porous body is configured so that the porous body is rough near the inner cylindrical tube and finer on the outer side. In other words, by coarsening the eyes near the inner cylindrical tube, it is easier to transmit the radiant heat from the inner cylindrical tube wall, and near the outer cylindrical tubes, the porous material is also finer, and the radiant heat is completely absorbed by the catalyst. In addition, the radiant heat from the inner cylindrical tube wall surface can be uniformly absorbed by the porous catalyst.

In the porous porous body, it is preferable that the porous material has a fine mesh near the inlet of the raw material gas and a rough mesh near the outlet. This is because the heat transfer coefficient is increased at the inlet of the raw material gas and the reaction is almost completed at the outlet, so that it is not necessary to increase the heat transfer coefficient.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. It should be noted that the materials and numerical values of the constituent members described in the following examples are merely examples, and do not specify the scope of the present invention.

(Embodiment 1) Referring to FIG. Here, FIG. 1 shows an overall view of a reformer with a spiral fin according to Embodiment 1 of the present invention.

Reference numeral 11 in the figure denotes an inner cylindrical tube, and an outer cylindrical tube 12 having a diameter different from that of the inner cylindrical tube 11 is arranged concentrically outside the inner cylindrical tube 11. The inner cylindrical tube 11
Spiral fins 13 having the same height as the gap with the outer cylindrical tube 12 are continuously welded or cast on the outer wall surface from one end to the other end of the inner cylindrical tube 11.
It is integrated with. A region surrounded by the outer wall surface of the inner cylindrical tube 11, the inner wall surface of the outer cylindrical tube 12, and the spiral fin 13 is filled with a granular reforming catalyst 14. Although not shown, a burner is arranged inside the inner cylindrical tube 11.

The raw material gas 15 flows through a space surrounded by the spiral fin 13, the inner cylindrical tube 11 and the outer cylindrical tube 12 while passing through a gap of the reforming catalyst 14. In the process, the source gas 15 is converted into the reformed gas 16. On the other hand, a heating gas 17 of, for example, 900 ° C. for supplying heat from a burner to the reforming catalyst 14 flows into the inside of the inner cylindrical tube 11 to heat the inner cylindrical tube 11. The heat energy from the heating gas 17 is transferred to the inner cylindrical tube 11.
From the outer wall surface and the surface of the spiral fin,
The heat is transmitted to the reforming catalyst 14 by heat conduction due to contact between the reforming catalyst 14 and the reforming catalyst 14 and forced convection heat conduction of the raw material gas 15 flowing through the gap between the reforming catalysts 14.

According to the first embodiment, since the spiral fins 13 having the same height as the gap with the outer cylindrical tube 12 are provided on the outer wall surface of the inner cylindrical tube 11, Can be transferred to the catalyst not only from the outer surface of the inner cylindrical tube but also from the fin surface. As a result, heat can also be supplied to the reforming catalyst 14 apart from the inner cylindrical tube, and the thickness of the catalyst layer can be increased. Therefore, it is possible to make the reforming tube containing a predetermined amount of the catalyst compact.

(Embodiment 2) Referring to FIGS. 2A and 2B. FIG. 2A is an explanatory view of a main part of a reformer with a spiral fin according to a second embodiment, and FIG.
FIG. Here, the same members as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. The reforming apparatus according to the second embodiment is similar to the reforming apparatus according to the first embodiment.
4 spiral fins 2
The difference is that 1, 2, 23, and 24 are formed from one end to the other end of the inner cylindrical tube 11. However, spiral fin 2
The height from 1 to 24 is almost the same as the gap between the inner cylindrical tube 11 and the outer cylindrical tube 12.

According to the second embodiment, by providing a plurality of spiral fins 21 to 24 in the inner cylindrical tube 11, the cross-sectional area of the flow path of the source gas can be arbitrarily adjusted by the fin pitch and the number of flow paths. An arbitrary gas flow rate can be set for a target reformed gas generation amount, that is, a predetermined catalyst amount.
Therefore, the gas flow rate can be increased to increase the forced convection transfer rate between the catalysts up to the maximum pressure drop that the system can tolerate,
The reforming catalyst 14 separated from the inner cylindrical tube 11 can be sufficiently heated, and the thickness of the catalyst layer can be further increased. As a result, even if the gas temperature for heating the inner cylindrical tube 11 is increased, the inner cylindrical tube 11
The heating of the reforming catalyst 14 adjacent to the outer wall surface above the endurance temperature of the catalyst can be avoided. Further, as the heating gas temperature increases, the amount of air supplied to the heating gas can be reduced, and the blowing power and the like can be reduced.

(Embodiment 3) Referring to FIG. However, FIG.
And the same members are denoted by the same reference numerals and description thereof is omitted. The reformer with a spiral fin according to the third embodiment is characterized in that a plurality of notches 25 are provided from the outer peripheral edge of the spiral fin 13 toward the central axis of the inner cylindrical tube. This is because, in the spiral fin 13, stress is generated due to a difference in thermal elongation between the root and the tip, and the spiral fin 13 may be broken depending on operating conditions. It is provided. That is, the notch 2
By providing the spiral fins 5, the stress can be reduced.

According to the third embodiment, the spiral fin 13
By providing a plurality of cutouts 25 from the outer peripheral edge of the spiral fin 13 toward the center axis of the inner cylindrical tube, it is possible to reduce the occurrence of stress due to the difference in thermal expansion between the root and the tip of the spiral fin 13. In the third embodiment, the interval and length of the notch can be set arbitrarily.

(Embodiment 4) Referring to FIG. Example 4
The reformer with spiral fin according to the first embodiment
Unlike the granular reforming catalysts provided in Nos. 1 to 3, the present invention is characterized in that a reforming catalyst 27 is applied and impregnated on a porous body 26 made of a porous material, for example, a cordierite material. The reforming catalyst 27 includes not only the surface of the porous body 26 but also
It is formed to penetrate inside.

According to the fourth embodiment, the heat transfer from the inner cylindrical tube and the surface of the spiral fin to the reforming catalyst 27 is caused not only by the heat conduction and the forced convection, but also by the porous body 26 having a light transmission distance. In addition, radiant heat transfer from the inner cylindrical tube and the surface of the spiral fin to the inside of the porous body becomes possible. Therefore, the thickness of the catalyst can be increased, and the apparatus can be made compact. Further, since the porous body has good heat transfer with the raw material gas due to its fine structure, the reforming performance is improved as compared with the granular catalyst.

[0031]

As described above in detail, according to the present invention, the spiral fin having a height equivalent to the gap of the double pipe is provided on the outer wall surface facing the outer cylindrical pipe side of the inner cylindrical pipe. By filling the space between the spiral fins with the catalyst, the necessary amount of the catalyst can be stored in a small space, and a compact reformer can be provided. In addition, by arbitrarily adjusting the cross-sectional area of the source gas flow path formed by the spiral fins by the fin pitch and the number of flow paths, the cross-sectional area of the raw material gas flow path can be arbitrarily set regardless of the amount of the catalyst. Gas flow rate can be increased. As a result, the heat transfer in the catalyst is improved, the thickness of the catalyst layer is increased, and the reforming tube and thus the reformer can be made compact. Furthermore, if a porous catalyst is used in place of the granular catalyst, the radiant heat from the inner wall surface and the spiral fins reaches the inside of the porous catalyst, and heat can be supplied to the inside of the thick catalyst. Can be made more compact. Further, since the porous body has a higher forced convection heat transfer coefficient to the raw material gas than the granular catalyst, the reforming performance can be improved.

[Brief description of the drawings]

FIG. 1 is an overall view of a reformer with a spiral fin according to a first embodiment of the present invention.

FIG. 2 is an explanatory view of a reformer with a spiral fin according to a second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a main part of a reformer with a spiral fin according to a third embodiment of the present invention.

FIG. 4 is a schematic perspective view of a porous body used in a reformer with a spiral fin according to Embodiment 4 of the present invention.

FIG. 5 is an explanatory view of a conventional reformer.

[Explanation of symbols]

 1,11 ... inner cylindrical tube, 2,12 ... outer cylindrical tube, 13, 21-24 ... spiral fin, 3, 14, 27 ... reforming catalyst, 5, 15 ... raw material gas, 6, 16 ... reformed gas, 4, 17: heating gas, 25: notch, 26: porous body.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G040 EA01 EB14 EB24 EB46 EC07 4G070 AA01 AB06 AB08 BB03 CA01 CB16 DA11 DA23 5H027 BA01

Claims (6)

[Claims] 1. A double pipe having an inner cylindrical pipe and an outer cylindrical pipe having different diameters arranged concentrically, wherein a heating gas flows into the inner cylindrical pipe to heat the inner surface thereof. A reforming catalyst is installed in the gap between the inner cylinder and the outer cylinder, and the raw material gas flows through the gap, and reforming is performed using heat supplied from the heating gas through the inner surface of the inner cylinder. Spiral fins having a height equivalent to the gap between the double tubes are provided on the outer wall surface facing the outer cylindrical tube side of the tube, a reforming catalyst is filled between the spiral fins, and a raw material gas is flowed between the spiral fins. A reformer characterized by flowing according to the following. 2. The method according to claim 1, wherein at least one spiral fin is provided to provide at least one gas flow path, and a distance between the fins is gradually increased from a gas inlet side to a gas outlet side. 2. The reformer according to 1. 3. The reformer according to claim 1, wherein a plurality of cutouts are provided from an outer peripheral edge of the spiral fin toward a central axis of the inner cylindrical tube. 4. The catalyst according to claim 1, wherein the catalyst is obtained by applying and impregnating a porous porous body with the catalyst.
The reforming apparatus according to claim 3. 5. The reformer according to claim 4, wherein the porous porous body has a structure in which the porosity is rough near the inner cylindrical tube and finer on the outside. 6. The reformer according to claim 4, wherein the porous porous body has a structure such that the porous material is coarse near the raw material gas inlet and finely porous near the raw material gas outlet.