JPH03106434A - Fuel reforming apparatus - Google Patents

Abstract

PURPOSE:To prevent that a space where no reforming catalyst is present is formed in a reaction chamber even when the volume of the reaction chamber expands during operation by thermal expansion by providing a pressing mechanism energizing an upper perforated plate toward the reforming catalyst in a reaction tube. CONSTITUTION:A burner 17 supplying combustion gas, a reaction tube 2 equipped with a cap 6, the reforming catalyst 5 received in the reaction chamber 3 formed between an outer tube 2a and the inner tube 2b, an upper perforated plate 4a and a lower perforated plate 4b are provided in a container 1. The raw material gas reformed by the heat exchange with the above-mentioned combustion gas in a process wherein the gas supplied into the container 1 from a supply port 9 to rise within the reaction chamber 3 is reversed at the upper end part in the reaction tube 2 to fall within the inner tube 2b and, during this time, the heat possessed by the falling gas is recovered by the raw material gas rising within the reaction chamber 3. The upper perforated plate 4a in the reaction tube 2 is pressed toward the reforming catalyst 5 by a pressing mechanism 20 consisting of racks 21, 23, a gear 22 and a support 24.

Description

[Detailed description of the invention]

[Object of the Invention] (Industrial Application Field) The present invention relates to a fuel reformer, and in particular to a fuel reformer that reacts a mixed fluid of hydrocarbons such as fuel oil, naphtha, and natural gas with steam in the presence of a reforming catalyst. , relates to a fuel reforming device for reforming a gas mixture consisting of hydrogen, carbon monoxide, carbon dioxide, methane, water vapor, etc. (-Prior Art) FIG. 5 shows a conventional double pipe type fuel reformer. In the figure, 1 indicates a container provided with a heat insulating layer, and a reaction tube 2 is disposed within 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 supported at its upper part by an upper perforated plate 4a and by its lower part by a lower perforated plate 4b. The upper porous plate 4a is connected to the lower porous plate 4b to prevent the reforming catalyst 5 from scattering upward.
supports 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 l2 is formed on the lower side of the lower support plate 7b, and this generated gas distribution chamber l2 communicates with a generated gas discharge port l3. Also,
A plug pipe 15 with a closed upper end is arranged concentrically inside the inner pipe 2b, and an annular regeneration chamber 1B is formed between the plug pipe 15 and the inner pipe 2b. It communicates with the gas distribution chamber 12. Also, container 1
A burner l7 is attached to the upper end of the burner l7, and a fuel supply port l8 and an air supply port l9 are formed in the burner l7. 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 1B, and then descends into the produced gas distribution chamber 12. The generated gas is then sent out from the generated gas outlet l3. 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 as follows: C H4 + H2 0 = C O + 3 H3-
49.27 Kcal/gaol, which is an endothermic reaction. To accelerate this reaction, heat must be supplied from the outside. This heat is supplied from burner 17 as combustion gas (indicated by points). Fuel is supplied from the fuel supply port 18 and air is supplied from the air supply port 19, and these are mixed and burned in the burner 17. Then, this combustion gas enters the combustion gas distribution chamber 10 and descends there. During this descent, after exchanging heat with the raw material gas (indicated by a solid line) rising in the reaction chamber 3, it is discharged from the combustion gas outlet 1l. (Problem to be solved by the invention Wi) 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. Particulate materials are used in which nickel is added to a ceramic base material. The material of this reaction tube 2 has a higher coefficient of linear expansion than the material of the reforming catalyst 5, and while the reaction tube 2 extends in the radial and axial directions while heat is being applied, 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 the reforming catalyst 5 flows, the particles of the reforming catalyst 5 are broken and powdered. When the particles of the reforming catalyst 5 are broken and powdered, the fragments and powder of the catalyst are carried by the raw gas flow to the produced gas distribution chamber 12.
Problems arise in that they may enter the chamber and adhere to the walls of the chamber, or they may adhere to downstream piping, valve equipment, etc. after being discharged outside the device, causing malfunctions or 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, may occur. C O + 3 H2 = C H4 + H2 0+
49.27Kcal/gaol When this reaction occurs, it causes an abnormal rise in temperature as it is a strong exothermic reaction, and also consumes hydrogen and carbon monoxide, which reduces the reforming efficiency of the fuel reformer. occurs. 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. The purpose of the present invention is to provide a fuel reformer that is constructed as follows.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a hollow container, a burner for supplying combustion gas into the container, and a burner arranged vertically in the container. a reaction tube formed into a double tube by arranging an outer tube and an inner tube concentrically and having a cap at the top; a reaction chamber formed between the outer tube and the inner tube; A reforming catalyst filled in a reaction chamber, an upper perforated plate that supports the reforming catalyst so that it does not scatter upward, and a lower perforated plate that supports the reforming catalyst so that it does not fall downward; The raw material gas, which is supplied into the container and reformed by heat exchange with the combustion gas in the process of rising inside the reaction chamber, is reversed at the upper end of the reaction tube, and while descending inside the inner tube. In a fuel reformer that recovers the retained heat to the raw material gas rising in the reaction chamber, an urging mechanism is provided inside the reaction tube to urge the upper perforated plate toward the reforming catalyst side. It is characterized by: (Function) According to the present invention, even if the reaction chamber expands due to thermal expansion during operation, the upper perforated plate is urged toward the reforming catalyst by that amount by the urging mechanism. According to
The reaction chamber is narrowed to prevent the formation of a space in which the reforming catalyst does not exist, and there is no flow space even if gas flows at a flow rate that would cause the reforming catalyst to flow during operation. Therefore, the reforming catalyst does not flow, and cracking and powdering of the catalyst are not 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. 5 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 tube in which an outer tube 2a and an inner tube 2b are 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 is supported at its upper part by an upper perforated plate 4a and by its lower part by a lower perforated plate 4b. The upper porous plate 4a supports the reforming catalyst 5 to prevent it from scattering upward, and the lower porous plate 4b supports the reforming catalyst 5 to prevent it 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 inner wall of the container l 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, and these upper support plates 7
A raw material gas chamber 8 is formed between a and the lower support plate 7b. This source gas chamber 8 communicates with a source gas supply port 9 . A combustion gas distribution chamber IO is formed above the upper support plate 7a, and this combustion gas distribution chamber IO communicates with the combustion gas discharge port 11 at its lower part. A generated gas distribution chamber 12 is formed on the lower side of the lower support plate 1b, and this generated gas distribution chamber 12 communicates with a generated gas outlet l3. The above configuration is the same as the conventional one. In addition to these configurations, a biasing mechanism 20 is provided inside the reaction tube 2 for biasing the upper porous plate 4a toward the reforming catalyst 5 in each operating state of the fuel reformer. This biasing mechanism 20 includes a rack 21 fixed to the inner wall of the outer tube 2a of the reaction tube 2, a gear 22 meshing with the rack 21, a rack 23 vertically fixed to the upper perforated plate 4a, and the gear 22.
and a support 24 connecting the inner tube 2b and the inner tube 2b. FIG. 2 shows an enlarged sectional view of this mechanism, and FIG. 3 shows another cross-sectional view of this mechanism. This biasing machine side 20 is connected to the outer pipe 2a during operation of the fuel reformer.
This utilizes the difference in thermal expansion caused by the temperature difference between the inner tube 2b and the inner tube 2b, and the operating principle is as follows. During operation of the fuel reformer, the outer tube 2a of the reaction tube 2 is connected to the inner tube 2.
The temperature is always high compared to b. For this reason, in the reaction tube 2 in which the outer tube 2a and the inner tube 2b are connected only at the lower end, there is a large amount of thermal expansion between the tip of the inner tube 2b and the opposing inner wall surface of the outer tube 2a during operation. It makes a difference. Therefore, due to this thermal expansion difference, the rack 2l is
This movement amount is transmitted to the rack 23 via the gear 22, and the upper perforated plate 4a is moved downward. At this time, the volume of the reaction chamber 3 expands due to thermal expansion, and the reforming catalyst 5 sinks to the lower region of the reaction chamber 3 by that amount. FIG. 4 shows the state of movement of the upper end surface of the reforming catalyst and the upper perforated plate 4a due to the urging mechanism 201 at this time under each operating load. Therefore, no space is created in the reaction chamber 3 where the reforming catalyst 5 is not present. By the way, during heating, the reaction tube 2 is extended and the volume of the reaction chamber 3 is expanded, so that the reforming catalyst 5 sinks to the lower region of the reaction chamber 3, and the reforming catalyst 5 is not in the reaction chamber 3. A space that does not exist is created. When the fuel reformer is operated in this state, depending on the flow rate of the raw material gas rising inside the reaction chamber 3, the reforming catalyst 5
flow occurs. When the reforming catalyst 5 flows, the particles of the reforming catalyst 5 are broken and pulverization occurs. When the reforming catalyst 5 is broken into particles and powdered, the fragments and powder of the catalyst enter the produced gas distribution chamber 12 along with the produced gas flow, adhere to the walls of the chamber, or are discharged outside the apparatus. Additionally, there is the problem that it may adhere to downstream piping, valve equipment, etc., causing breakdowns and abnormalities. According to this embodiment, even if the reaction chamber 3 expands due to thermal expansion during operation, the lateral 200 mm of the energizing device can be expanded by that amount.
automatically pushes down the upper porous plate 4b, so there is no space in the reaction chamber 3 that is filled with the reforming catalyst 5, and therefore the reforming catalyst 5 in the reaction chamber 3 does not flow. , the particles of the reforming catalyst 5 do not crack or become powder. Therefore, the fragments and powder of the reforming catalyst 5 will not be mixed into the raw material gas flowing into the regeneration chamber 1B, and therefore the fragments and powder of the reforming catalyst 5 will not flow downstream, and these will not be absorbed into the produced gas. It is possible to prevent harmful effects such as adhesion to the chamber wall of the circulation chamber l2 or adhesion to downstream piping, valves, equipment, etc. outside the apparatus. [Effects of the Invention] As is clear from the above description, according to the present invention, even if the reaction chamber expands due to thermal expansion during operation, the biasing mechanism is configured to narrow the reaction chamber by that amount. Therefore, there is no concern that there will be a space in the reaction chamber that is not filled with the reforming catalyst, and therefore a part of the reforming catalyst will not flow within the reaction chamber, resulting in cracks in the reforming catalyst, powdering, etc. This will prevent any inconvenience from occurring.

[Brief explanation of drawings]

Fig. 1 is a sectional view showing an embodiment of a fuel reformer according to the present invention, Fig. 2 is a sectional view of an embodiment showing the invention in more detail, and Fig. 3 is a sectional view of the embodiment shown in Fig. 2. 4 is a graph showing the level fluctuation of the upper end surface of the catalyst layer and the level fluctuation of the upper perforated plate according to the present invention at each load during operation of the fuel reformer, and FIG. 5 is a graph showing the level fluctuation of the upper perforated plate according to the present invention. It is a sectional view showing a reforming device. 1... Container 2a... Outer tube 3... Reaction chamber 4b... Lower porous plate 6... Insulating cap 2l... Rack 23... Rack 2... Reaction tube 2b... Inner tube 4a...Upper perforated plate 5...Reforming catalyst 20...Biasing mechanism 22...Gear 24...Support

Claims (1)

[Scope of Claims] 1. A hollow container, a burner for supplying combustion gas into the container, and a double-walled structure arranged vertically in the container and having an outer tube and an inner tube arranged concentrically. A reaction tube configured as a tube and equipped 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 reforming catalyst arranged above. an upper perforated plate that supports the reforming catalyst so that it does not scatter, and a lower perforated plate that supports the reforming catalyst so that it does not fall downward; The raw material gas to be reformed by heat exchange is reversed at the upper end of the reaction tube, and the heat retained while descending inside the inner tube is recovered to the raw material gas rising within the reaction chamber. 1. A fuel reforming device characterized in that a biasing mechanism for biasing the upper perforated plate toward the reforming catalyst is provided inside the reaction tube. 2. The upper part of the reforming catalyst has a mechanism that utilizes the difference in thermal expansion between the outer reaction tube and the inner reaction tube to always keep the gap between the upper end surface of the reforming catalyst and the upper perforated plate to a minimum in all operating ranges. The fuel reformer according to claim 1, characterized in that: