JPH03238037A - Fuel reforming apparatus - Google Patents

Abstract

PURPOSE:Not to form a space without reforming catalyst in a reaction chamber owing to volume expansion of the reaction chamber by thermal expansion during work time by installing a spring part, which expands and contracts following the expansion and contraction of a reaction tube in the same direction as those of the reaction tube in its longitudinal direction, in the reaction chamber. CONSTITUTION:A combustion gas is supplied to a container 1 by a burner 17. A reaction chamber 3 is filled with a reforming catalyst 5. Further, a raw material gas which is supplied to the container 1 through a raw material gas supplying inlet 9 and reformed by heat-exchange with the combustion gas while rising in a reaction chamber 3 is turned at the upper end of a reaction tube 2 and the heat preserved in the raw material gas is made to be recovered by a raw material gas rising in the reaction chamber 3 while the former raw material gas descends in an inner tube 2b. A spring part 20 which expands and contracts following the expansion and contraction of the reaction tube 2 in the same direction as those of the reaction tube 2 in its longitudinal direction is installed in the reaction chamber 3. As a result, even if the volume of the reaction chamber is expanded owing to the thermal expansion during the work time, no space without reforming catalyst is formed in the reaction chamber.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a fuel reforming device, and in particular is used to reform a mixed fluid of hydrocarbons such as fuel oil, naphtha, and natural gas and steam. The present invention relates to a fuel reforming device that reacts in the presence of a catalyst to reform a mixed gas consisting of hydrogen, carbon oxide, carbon dioxide, methane, water vapor, etc.

(Conventional technology) FIG. 5 shows a conventional double pipe type fuel reformer.

In the figure, the shank indicates a container provided with a heat insulating layer, and a reaction tube 2 is placed inside this container 1. The reaction tube 2 is a double tube in which an outer tube 2a and an inner tube 2b are arranged concentrically, and an annular reaction chamber 3 is formed between the outer tube 2a and the inner tube 2b. The reaction chamber 3 is filled with a reforming catalyst 5, and the reforming catalyst 5 is covered at its upper part with an upper perforated plate 4a and its lower part with a lower perforated plate 4b. The upper porous plate 4a confines the reforming catalyst 5 so that it does not scatter upward, and the lower porous plate 4b confines the reforming catalyst 5 so that it does not fall downward. Further, a heat insulating cap 6 is attached to the top of the reaction tube 2 to protect the head of the reaction tube 2 from high temperature combustion gas. Further, the lower end of the outer tube 2a and the inner wall of the container 1 are connected by an annular upper support plate 7a, while the lower end of the inner tube 2b and the inner wall of the container 1 are connected by an annular lower support plate 7b. A source gas chamber 8 is formed between the support plate 7a and the lower support plate 7b. This source gas chamber 8 communicates with a source gas supply port 9 . A combustion gas distribution chamber 10 is formed above the upper support plate 7a, and the combustion gas distribution chamber 10 communicates with a combustion gas discharge port 11 at its lower portion. Further, a generated gas distribution chamber 12 is formed on the lower side of the lower support plate 7b,
This generated gas distribution chamber 12 communicates with a generated gas outlet 13 . Further, a plug pipe 15 with a closed upper end is arranged concentrically inside the inner pipe 2b, and an annular regeneration chamber 16 is formed between the plug pipe 15 and the inner pipe 2b.
communicates with the generated gas distribution chamber 12 at its lower part. Further, a burner 17 is attached to the upper end of the container 1, and a fuel supply port 18 and an air supply port 19 are formed in the burner 17.

In the conventional fuel reformer configured as described above, raw material gas for reforming is supplied from the gas supply port 9. This raw material gas enters the annular reaction chamber 3 through the raw material gas chamber 8, rises there, turns around at the upper end of the reaction tube 2, descends inside the regeneration chamber 16, and then descends into the produced gas distribution chamber 12. The generated gas is then sent out from the generated gas outlet 13.

By the way, since the reaction chamber 3 is filled with a reforming catalyst 5, the raw material gas is reformed while rising there. This reforming reaction is: C) I4820 = CO+3H2 49,27KcaQ/gmoff, which is an endothermic reaction. Heat must be supplied from the outside to accelerate this reaction.

This heat is supplied from burner 17 as combustion gas (indicated by dotted lines). Fuel is supplied from the fuel supply port 18 and air is supplied from the air supply port 19, and these 3-4- are mixed and burned in the burner 17. Then, this combustion gas enters the combustion gas distribution chamber 10 and descends.After exchanging heat with the raw material gas (indicated by a solid line) rising in the reaction chamber 3 during the descent, the combustion gas exits from the combustion gas outlet 11. be discharged.

(Problems to be Solved by the Invention) By the way, the conventional reaction tube 2 described above uses a heat-resistant alloy tube made of high nickel high chromium steel manufactured by centrifugal casting, and the reforming catalyst 5 is made of alumina or the like. A particulate material in which nickel is added to a ceramic base material is used. The material of this reaction qlt2 has a larger coefficient of linear expansion than the material of the reforming catalyst 5, and while heat is being applied, the reaction tube 2
extends in the radial and axial directions, whereas the reforming catalyst 5
hardly grows.

Therefore, during heating, the reforming catalyst 5 sinks to the lower region of the reaction chamber 3 by the amount that the reaction tube 2 is extended and the volume of the reaction chamber 3 is expanded, and the reforming catalyst 5 is in the reaction chamber 3. A space that does not exist is created. When the fuel reformer is operated in this state, the reforming catalyst 5 flows due to the raw material gas rising in the reaction chamber 3. When this flow of the reforming catalyst 5 occurs, the particles of the reforming catalyst 5 may break and pulverization may progress. Fragments and powder of the catalyst may enter the produced gas distribution chamber 12 along with the produced gas flow and adhere to the chamber wall, or may adhere to downstream piping, valve equipment, etc. after being discharged outside the device. This causes problems such as failures and abnormalities.

Moreover, in such a case, there is a possibility that a methanation reaction, which is a reverse reaction of the above-mentioned reforming reaction, will occur.

CO+3)+2=CH,+820+49,27KcaQ/gmoR When this reaction occurs, it causes an abnormal rise in temperature as it is a strong exothermic reaction, and also consumes hydrogen and carbon oxides, causing a problem in the fuel reformer. A problem arises in that quality efficiency is reduced.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional technology, so that even if the volume of the reaction chamber expands due to thermal expansion during operation, a space in which the reforming catalyst does not exist will not be formed in the reaction chamber. An object of the present invention is to provide a fuel reforming device as described above.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a hollow container, a burner for supplying combustion gas into the container, and an outer pipe arranged vertically in the container. A reaction tube configured as a double tube with an inner tube arranged concentrically and equipped with a cap at the top, a reaction chamber formed between the outer tube and the inner tube, and a reformer filled in this reaction chamber. It is equipped with a catalyst, an upper perforated plate that covers the upper part of the reaction chamber to prevent the reforming catalyst from scattering upward, and a lower perforated plate that covers the lower part of the reaction chamber to prevent the reforming catalyst from falling downward. The raw material gas is reformed by heat exchange with the combustion gas as it rises inside the reaction chamber.
In a fuel reformer, the reaction tube is inverted at the upper end of the reaction tube so that the heat retained while descending inside the inner tube is recovered to the raw material gas rising inside the reaction chamber. It is characterized by providing a spring member that expands and contracts in the same direction following the expansion and contraction in the longitudinal direction.

(Function) According to the present invention, even if the reaction chamber expands due to thermal expansion during operation, the spring member installed inside the reaction chamber also displaces within the catalyst layer in the longitudinal and radial directions due to thermal expansion. The catalyst layer in contact with the spring member is pushed up, which ultimately changes the packing density of the reforming catalyst and prevents the formation of a space in the reaction chamber where no reforming catalyst exists. Even if gas flows at a flow rate that would cause the reforming catalyst to flow, there is no flow space, so the reforming catalyst does not flow, and the reforming catalyst will not crack or its pulverization will not be promoted. .

(Embodiment) Hereinafter, an embodiment of a fuel reformer according to the present invention will be described with reference to FIG. 1, in which the same parts as in FIG. 3 are denoted by the same reference numerals.

In FIG. 1, 1 indicates a container equipped with a heat insulating layer, and a reaction tube 2 is placed inside this container 1. This reaction tube 2 is a double-layered container with an outer tube 2a and an inner tube 2b arranged concentrically. An annular reaction chamber 3 is formed between the outer tube 2a and the inner tube 2b. This reaction chamber 3 is filled with a reforming catalyst 5, and the reforming catalyst 5 has an upper porous plate 4 at the top.
At a, the lower part is covered with a lower perforated plate 4b. The upper porous plate 4a confines the reforming catalyst 5 to prevent it from scattering upward, and the lower porous plate 4b confines the reforming catalyst 5 from falling downward. Furthermore, a heat insulating cap 6 is attached to the top of the reaction tube 2 to protect the head of the reaction tube 2 from high temperature combustion gas. The lower end of the outer tube 2a and the container 1
The inner wall of the inner tube 2b is connected to the inner wall of the container 1 by an annular upper support plate 7a, while the lower end of the inner tube 2b and the inner wall of the container 1 are connected by an annular lower support plate 7b. A raw material gas chamber 8 is formed between them. This source gas chamber 8 communicates with a source gas supply port 9 .

A combustion gas distribution chamber 10 is formed above the upper support plate 17a, and the combustion gas distribution chamber 10 communicates with a combustion gas discharge port 11 at its lower portion. A generated gas distribution chamber 12 is formed on the lower side of the lower support plate 7b, and this generated gas distribution chamber 12 communicates with a generated gas discharge port 13. The above configuration is the same as the conventional one.

In this embodiment, in addition to the above structure, a metal coil spring 20 having a large coefficient of linear expansion is installed inside the reaction tube 2 and inside the reaction chamber 3.

As shown in the construction drawing, this coil spring 20 is compressed by being sandwiched between a lower perforated plate 4b fixed to the inner tube 2b or outer tube 2a and an upper perforated plate 4a fixed to the inner tube 2b or outer tube 2a. is in a state of

Next, the operation based on the above configuration will be explained.

During operation of the fuel reformer, the raw material gas in the reaction chamber 3 inside the reaction tube 2 is heated from the outer tube 2a side, and the reaction tube 2 thermally expands in the longitudinal direction.
Although the distance increases, since the coil spring 20 is in a compressed state, the lower perforated plate 4b and the upper perforated plate 4a extend in the same direction with both ends touching.

The state in which the coil spring 20 is displaced is shown in FIG. 1a, and it can be seen that when the coil 20 as a whole is displaced L1 in the longitudinal direction, the intermediate portion thereof is displaced by L2 and L3 respectively.

Therefore, when the coil spring 20 is displaced, the reforming catalyst 5 filled in the reaction chamber 3 and in contact with the coil 20 is pushed upward, and the catalyst packing density around the coil spring 20 is changed due to the influence of the fluid force of the raw material gas. Due to the synergistic effect, it can be reduced slightly and increase the volume of the entire catalyst layer.

Therefore, when the volume of the reaction chamber 3 increases due to thermal expansion, the volume of the entire catalyst layer also increases due to the action of the coil spring 20, so that the sinking of the reforming catalyst 5 in the reaction chamber 3 is minimized, and the reaction It is possible to prevent the creation of a space in the chamber 3 where the reforming catalyst 5 does not exist.

In addition, even if the coil spring 20 hits the upper porous plate 48 or the like due to thermal expansion, it will contract by itself and will not exert a large force on these members.

As another embodiment, in FIG. 2, a coil spring 21 whose upper and lower ends are fixed to the outer tube 2a of the reaction tube 2 is used. This is used to make the variation in the longitudinal direction dependent on the thermal expansion of the outer tube 2a. In this case, the operation in the longitudinal direction becomes more reliable and the heat transfer performance within the catalyst layer can also be improved.

In FIG. 3, the coil spring has a rectangular cross section instead of a circular cross section, so that the influence of the displacement of the coil spring 22 is transmitted more reliably to the catalyst layer.

FIG. 4 shows the coil spring 20 shown in FIG. 1 by attaching perforated plates 23 shown in FIG. 4a at equal pitches.
This is intended to enhance the effect of displacement in the longitudinal direction of 2.

In this way, there is no possibility that fragments and powder of the reforming catalyst 5 will be mixed into the raw material gas flowing into the regeneration chamber 16, and the fragments and powder of the reforming catalyst 5 will flow downstream and be transferred to the produced gas distribution chamber. It is possible to eliminate inconveniences such as adhesion to the walls of the 12 chambers or to downstream piping, valves, equipment, etc. outside the apparatus.

〔Effect of the invention〕

As is clear from the above description, the present invention is configured such that even if the volume of the reaction chamber expands due to thermal expansion during operation, the spring member stretches accordingly to increase the volume of the entire catalyst layer. Therefore, a space not filled with the reforming catalyst, which would cause the reforming catalyst to flow, is not created in the reaction chamber.

1-12- Therefore, according to the present invention, cracks occur in the reforming catalyst,
This has the effect that the fuel reformer can maintain stable performance over a long period of time without causing inconveniences such as progress of powdering.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one embodiment of a fuel reformer according to the present invention, FIG. 1a is an explanatory diagram for explaining the operation of the present invention, and FIGS. 2 to 4 are other embodiments of the present invention. FIG. 4a is an enlarged perspective view of the perforated plate of FIG. 4, and FIG. 5 is a cross-sectional view of a conventional fuel reformer. l... Container 2... Reaction tube 2a...
Outer tube 2b...Inner tube 3...Reaction chamber
4a... Upper perforated plate 4b... Lower perforated plate
5... Reforming catalyst 6... Adiabatic gap 2
0, 21, 22...Coil spring 23...Perforated plate

Claims (1)

[Claims] (1) A hollow container, a burner for supplying combustion gas into the container, arranged vertically in the container, and configured into a double pipe with an outer tube and an inner tube arranged concentrically; A reaction tube provided with a cap at the top, a reaction chamber formed between the outer tube and the inner tube, a reforming catalyst filled in the reaction chamber, and a method to prevent the reforming catalyst from scattering upward. A process in which the reforming catalyst is supplied into the container and ascends within the reaction chamber, comprising an upper perforated plate that covers the upper part of the reaction chamber and a lower perforated plate that covers the lower part of the reaction chamber to prevent the reforming catalyst from falling downward. The raw material gas that is reformed by heat exchange with the above combustion gas is
In the fuel reformer, the reaction tube is inverted at the upper end of the inner tube so that the heat retained while descending inside the inner tube is recovered to the raw material gas rising in the reaction chamber. A fuel reforming device characterized in that a spring member is provided in the chamber that expands and contracts in the same direction as the reaction tube expands and contracts in the longitudinal direction.