Fuel reformer

Abstract

The present invention provides a fuel reformer comprising: a combustion gas supply pipe located in the center of the fuel reformer, forming a space in which a heat source can be placed; a combustion gas flow path pipe formed to be longer than the length of the combustion gas supply pipe, allowing combustion gas generated from the heat source to flow into the fuel reformer through a lower section that communicates with the combustion gas supply pipe; a reforming reaction pipe having a larger diameter than the combustion gas flow path pipe and having a catalyst layer inside; and a bellows pipe located above the reforming reaction pipe, formed in a double helix shape, supplied with raw material gas and raw material water together, and discharging the preheated raw material gas and raw material water to the reforming reaction pipe in a split manner.

Description

Technical Field

[0001] The present invention relates to a fuel reformer, and more particularly to a fuel reformer including a double-coil bellows tube and a plurality of distribution plates.

Background Art

[0002] As an example of the applicable scope of the present invention, there is a reforming reactor (hereinafter referred to as a reformer) that produces hydrogen by steam reforming reaction of natural gas. The reformer is a reactor that produces hydrogen using natural gas mainly composed of methane as a raw material. The raw material gas and steam are converted into a reformed gas in which hydrogen, carbon monoxide, and carbon dioxide are mixed on a catalyst, and a strong endothermic reaction occurs, so that separate supply of reaction heat is required.

[0003] A concentric tube type fuel reformer has a combustion chamber in the central part, and by burning fuel, it preheats water and natural gas, which are reaction raw materials, and supplies heat required for the fuel reforming reaction. A catalyst layer is located in a cylinder shape on the outer periphery of the combustion chamber, and since the combustion chamber is located in the center, the outlet of the reformed gas is located on the side surface rather than in the center.

[0004] The fuel reformer is configured with all processes in cooperation with a steam generator required for the reaction and a preheater that preheats reactants. At this time, the heat of the steam generator and the preheater can be supplied by recovering waste heat from the combustion exhaust gas discharged by heating the catalyst layer or the reformed gas generated. Therefore, it is required to increase the heat exchange efficiency in order to increase the efficiency of the entire process including the steam reformer.

[0005] Conventional industrial reformers use tube reactors, and heat exchange is primarily performed by radiation heat transfer. In this configuration, the heat flux to the reaction tubes relative to the reaction heat generated in the combustor is very large, which is advantageous for maximizing processing capacity. However, there is a risk of localized heating of the reaction tubes due to direct contact with the flame, etc., which prevents a uniform reaction and reduces reaction stability and conversion efficiency. Furthermore, large reaction deviations between reactors make operation, maintenance, and management difficult, and require expensive heat-resistant materials within the equipment.

[0006] This poses a major obstacle to miniaturizing the equipment. In small reformers, convective heat transfer is primarily used for heat exchange. To minimize equipment volume while increasing heat exchange efficiency within the fuel reformer, concentric tube reactors are employed. Research and development are needed to improve the raw material distribution efficiency and thermal efficiency in small reformers. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The technical problem that this invention aims to solve is to provide a fuel reformer that improves the distribution efficiency and thermal efficiency of the reformed reaction product by providing a double-coiled bellows tube and a plurality of distribution plates.

[0008] The technical problems that this invention aims to solve are not limited to those mentioned above, and other technical problems not mentioned will be clearly understood by a person with ordinary skill in the art to which this invention pertains from the following description. [Means for solving the problem]

[0009] To achieve the above technical objectives, one embodiment of the present invention provides a fuel reformer comprising: a combustion gas supply pipe located in the center of the fuel reformer and forming a space in which a heat source can be placed; a combustion gas flow path pipe formed to be longer than the length of the combustion gas supply pipe, through which combustion gas generated from the heat source flows into the interior via a lower section that can communicate with the combustion gas supply pipe; a reforming reaction pipe having a larger diameter than the combustion gas flow path pipe and having a catalyst layer inside; and a bellows pipe located above the reforming reaction pipe, formed in a double helix shape, which is supplied with raw material gas and raw material water together, and which separates and discharges the preheated raw material gas and raw material water to the reforming reaction pipe.

[0010] In embodiments of the present invention, the bellows tube is formed in a double helix shape surrounding the combustion gas flow tube and may include raw material gas inlets provided at opposing positions on the upper part and raw material gas outlets provided at opposing positions on the lower part.

[0011] In embodiments of the present invention, a heat exchange tube may be further included, which has a space in which the bellows tube can be arranged and which has a flow path formed inside through which the combustion gas flowing in from the combustion gas flow path tube can pass.

[0012] In an embodiment of the present invention, the heat exchange tube may have a vent hole formed on its lower inner side through which combustion gas that has passed through the combustion gas flow path tube can flow in, and a combustion gas outlet formed on its upper outer side.

[0013] In embodiments of the present invention, the reforming reaction tube may further include a distribution plate formed on a flow path toward the catalyst layer, which guides the preheated raw material gas and raw material water discharged from the bellows tube to be supplied to the catalyst layer uniformly.

[0014] In embodiments of the present invention, the distribution plate includes a first distribution plate, a second distribution plate located below the first distribution plate, and a third distribution plate located below the second distribution plate, wherein the second distribution plate may be positioned at an angle of axial rotation of 15° to 30° relative to the first and third distribution plates.

[0015] In embodiments of the present invention, heat transfer fins formed in a partition-like manner on the outer surface of the combustion gas flow channel may be further included in order to supply heat to the catalyst layer formed between the combustion gas flow channel and the reforming reaction channel.

[0016] In embodiments of the present invention, the heat transfer fins include a plurality of heat transfer fins provided at intervals along the outer surface of the combustion gas flow path tube, and each of the plurality of heat transfer fins may be formed at a predetermined distance from adjacent heat transfer fins in the height direction.

[0017] In embodiments of the present invention, a reformed gas discharge pipe may be further included, which is shaped to surround the reformed reaction pipe, through which the reformed gas flows into the interior via a lower section that can communicate with the reformed reaction pipe, and which has a reformed gas discharge port formed on its upper outer side for discharging the reformed gas. [Effects of the Invention]

[0018] According to embodiments of the present invention, by providing a double-coiled bellows tube and a plurality of distribution plates, the distribution efficiency and thermal efficiency of the reformed reaction product can be improved.

[0019] The effects of the present invention are not limited to those described above, but are understood to include all effects that can be inferred from the detailed description of the present invention or the configuration of the invention as described in the claims. [Brief explanation of the drawing]

[0020] [Figure 1] This is a schematic diagram showing the overall configuration of a fuel reformer according to one embodiment of the present invention. [Figure 2]It is a diagram showing a state where a bellows tube is provided according to an embodiment of the present invention. [Figure 3] It is a diagram showing a state where a distribution plate is provided according to an embodiment of the present invention. [Figure 4] It is a schematic diagram showing a state where heat transfer fins are provided according to an embodiment of the present invention.

Mode for Carrying Out the Invention

[0021] Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the present invention can be realized in various different forms and is not limited to the embodiments described here. Also, in the drawings, for the purpose of clearly explaining the present invention, descriptions of parts not related to the explanation are omitted, and throughout the specification, similar parts are given similar reference numerals.

[0022] Throughout the specification, when it is stated that a certain part is "connected (connected, contacted, coupled)" to another part, this includes not only the case where it is "directly connected", but also the case where it is "indirectly connected" with other elements interposed therebetween. Also, throughout the specification, when a certain part is stated to "include" a certain component, this means that, unless otherwise specified, it does not exclude other components and may further include other components.

[0023] The terms used in this specification are merely used to explain specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly gives a different meaning. In this specification, terms such as "including" or "having" specify the presence of the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, and it is understood that they do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof in advance.

[0024] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0025] FIG. 1 is a schematic diagram showing the overall configuration of a fuel reformer according to an embodiment of the present invention, FIG. 2 is a diagram showing a state in which a bellows tube is provided according to an embodiment of the present invention, and FIG. 3 is a diagram showing a state in which a distribution plate is provided according to an embodiment of the present invention.

[0026] Referring to FIG. 1, the fuel reformer of the present invention may include a heat source 100, a combustion gas supply pipe 200, a combustion gas flow path pipe 300, a reforming reaction pipe 400, a reformed gas discharge pipe 500, a heat exchange pipe 600, a bellows tube 700, and a distribution plate 800.

[0027] The fuel reformer of the present invention may include at least one reaction conduit (tube) for reforming a raw material gas. A heat source 100 may be disposed at the inner center of the fuel reformer.

[0028] The heat source 100 supplies the reaction heat required for the reforming reaction, and can burn air and fuel supplied from the outside to generate combustion gas at the inner center of the fuel reformer. The heat source 100 (hereinafter, the combustor) according to the present invention may be embodied as, for example, a burner. Here, the combustion fuel supplied to the heat source 100 may be the same natural gas (NG) as the raw material of the reformer.

[0029] The combustion gas supply pipe 200 may be disposed at the inner center of the fuel reformer, and a space in which the combustor 100 can be disposed may be formed. The combustor 100 provided inside the combustion gas supply pipe 200 may be disposed at the upper center of the combustion gas supply pipe 200.

[0030] The combustion gas flow path pipe 300 is disposed concentrically with the combustion gas supply pipe 200 and may have a diameter larger than that of the combustion gas supply pipe 200. That is, the combustion gas flow path pipe 300 may be formed in a shape surrounding the combustion gas supply pipe 200.

[0031] Referring to Figure 1, the combustion gas flow path pipe 300 may be formed to be longer than the length of the combustion gas supply pipe 200. Here, the length of the combustion gas flow path pipe 300 may mean the length from the bottom surface of the fuel reformer to the top of the fuel reformer where the raw material gas inlets 711 and 713 are located.

[0032] As a result, the open lower portion of the combustion gas supply pipe 200 may be provided in a shape that allows it to communicate with the combustion gas flow pipe 300. The combustion gas generated from the combustor 100 descends to the lower portion of the combustion gas supply pipe 200, flows into the lower portion of the combustion gas flow pipe 300, and can travel along a path that rises towards the upper portion of the combustion gas flow pipe 300.

[0033] In other words, the donut-shaped space formed between the combustion gas supply pipe 200 and the gas flow path pipe 300 becomes a combustion gas flow path through which the combustion gas (exhaust gas) flows. To allow for the discharge of combustion gas (EG), the lower end of the combustion gas supply pipe 200 is spaced apart from the bottom surface of the fuel reformer and may have a structure in which the lower part is open.

[0034] The combustion gas (EG) generated in the combustor 100 provides the necessary reaction heat to the reforming reaction tube 400 formed on one side immediately after passing through the combustion gas flow path, superheats the raw material mixture (raw material gas and raw material water) supplied to the reforming reaction tube 400, then passes through the heat exchange tube 600 provided on one side of the upper part of the combustion gas flow path tube 300, preheats the raw material mixture injected via the bellows tube 700, and may then be exhausted to the combustion gas outlet 630.

[0035] The reforming reaction tube 400 is arranged concentrically with the combustion gas flow channel tube 300, but may have a larger diameter than the combustion gas flow channel tube 300, so as to surround the combustion gas flow channel tube 300. As shown in Figure 1, a catalyst layer 410 for the reforming reaction may be provided in the lower region of the reforming reaction tube 400.

[0036] The reformed gas discharge pipe 500 may be arranged concentrically with the reformed reaction pipe 400 and may be formed in a shape that surrounds the reformed reaction pipe 400.

[0037] Referring to Figure 1, the lower part of the reformed gas reaction tube 400 has an open shape, and similar to the combustion gas supply tube 200, the lower part of the reformed gas reaction tube 400 is spaced apart from the bottom surface of the fuel reformer and may have a structure that allows it to communicate with the reformed gas discharge tube 500. As a result, the reformed gas generated when the raw material mixture passes through the catalyst layer 410 may flow into the reformed gas discharge tube 500 through the open lower part of the reformed gas reaction tube 400, move upward, and then be discharged through the reformed gas outlet 510.

[0038] The reformed gas outlet 510 may be formed on the upper outer side of the reformed gas outlet pipe 500.

[0039] The heat exchange tube 600 may be arranged concentrically with the combustion gas flow path tube 300 and may be formed in a shape that surrounds the upper part of the combustion gas flow path tube 300. The heat exchange tube 600 may have a space formed inside in which a bellows tube 700 can be arranged.

[0040] The heat exchange tube 600 may have a vent hole 610 on its lower inner side and a combustion gas outlet 630 on its upper outer side. The combustion gas that has passed through the combustion gas flow path tube 300 can enter the inside of the heat exchange tube 600 through the vent hole 610, pass through the flow path between the bellows tubes 700, and be exhausted to the outside through the combustion gas outlet 630.

[0041] The bellows tube 700 is a heat exchange conduit that forms an injection path through which a raw material mixture containing raw gas and raw water is injected into the fuel reformer, and heat exchange can occur between the combustion gas (EG) flowing outside the bellows tube 700 and the raw material mixture flowing inside the bellows tube 700.

[0042] The bellows tube 700 is located in the internal space of the heat exchange tube 600 and may be formed in a double helix shape to increase the heat exchange area. The upper part of the bellows tube 700 may have raw material gas inlets 711 and 713 positioned opposite each other, and the lower part may have raw material gas outlets 731 and 733 positioned opposite each other (see Figure 1).

[0043] According to one embodiment, the bellows tube 700 may be formed in a coil shape by winding the combustion gas flow path tube 300 multiple times, and a first raw material gas inlet 711 may be provided at the upper part of the circularly formed bellows tube 700, and a second raw material gas inlet 713 may be provided at an angle of 170 to 190 degrees from the position of the first raw material gas inlet 711. Similarly, a first raw material gas outlet 731 may be provided at the lower part of the bellows tube 700, and a second raw material gas outlet 733 may be provided at an angle of 170 to 190 degrees from the position of the first raw material gas outlet 731.

[0044] The raw material mixture injected into the raw material gas inlets 711 and 713 undergoes heat exchange, and the preheated raw material mixture (raw material gas and raw material water) may be discharged to the reforming reaction tube 400 via the raw material gas outlets 731 and 733. In this case, the raw material mixture supplied to the inside of the fuel reformer may be injected in a predetermined amount, and it is preferable that half of the predetermined amount of raw material mixture is injected into the first raw material gas inlet 711 and the second raw material gas inlet 713, respectively, and half of the total amount of preheated raw material mixture is discharged via the first raw material gas outlet 731 and the second raw material gas outlet 733, respectively.

[0045] Referring to Figure 1, the lower ends of the raw material gas outlets 731 and 733 may be formed in a shape that allows them to be inserted into the reforming reaction tube 400.

[0046] In one embodiment, the total length of the bellows tube 700 is 5 to 15 m, preferably 8.2 m, and it may be formed in a shape that surrounds the combustion gas flow path tube 300 in two rows. However, the length of the bellows tube 700 is not limited to this, and it may be provided in a length corresponding to the diameter of the combustion gas flow path tube 300 to be realized.

[0047] The distribution plate 800 may be located inside the reforming reaction tube 400. Specifically, the distribution plate 800 may be positioned on the flow path through which the preheated raw material mixture discharged from the bellows tube 700 is directed toward the catalyst layer 410.

[0048] The distribution plate 800 can serve to ensure that the preheated raw material mixture is uniformly supplied to the catalyst layer 410. The distribution plate 800 may be formed in the shape of a flat ring with distribution vents formed at equal intervals, as shown in Figure 1.

[0049] The distribution plate 800 according to one embodiment of the present invention may include a first distribution plate 810, a second distribution plate 830, and a third distribution plate 850. The first distribution plate 810 may be located at the top of the distribution plate and adjacent to the bellows tube 700. The second distribution plate 830 may be located below the first distribution plate 810, and the third distribution plate 850 may be located below the second distribution plate 830.

[0050] In this case, the second distribution plate 830 may be positioned at an angle rotated axially by 15° to 30° relative to the first distribution plate 810 and the third distribution plate 850. For example, the second distribution plate 830 may be positioned at an angle rotated axially by 18° relative to the first and third distribution plates 810 and 850. In this case, the first distribution plate 810 and the third distribution plate 850 may be positioned at the same angle so that the positions of the ventilation holes coincide. For example, each of the first to third distribution plates may contain 10 ventilation holes, and the 10 ventilation holes may be arranged at equal intervals from one another.

[0051] Since the second distribution plate 830 is positioned at an angle rotated by a predetermined angle relative to the first and third distribution plates 810 and 850, the ventilation holes formed in the second distribution plate 830 and the ventilation holes formed in the first and third distribution plates 810 and 850 may be offset from each other.

[0052] Since the first to third distribution plates 810, 830, and 850 described above are positioned between the bellows pipe 700 and the catalyst layer 410, the raw material mixture (raw material gas and raw material water) that has been separated and discharged from the bellows pipe 700 and passed through the first to third distribution plates 810, 830, and 850 can be supplied to the catalyst layer 410 in a uniform distribution.

[0053] Figure 3 shows a diagram illustrating a distribution plate according to one embodiment of the present invention. The first distribution plate 810, the second distribution plate 830, and the third distribution plate 850 of the present invention can each be realized with a diameter of 1Φ. In this invention, the example of providing three distribution plates 800 has been described, but the number of distribution plates is not limited to this and can be varied in various ways as needed.

[0054] The raw material gas injected into the bellows tube 700 may be a hydrocarbon (LNG, LPG, etc.) raw material, and the hydrocarbon raw material may have its sulfur components removed. Such raw materials and raw water are injected together into the bellows tube 700 in a divided manner and, through heat exchange with the combustion gas, the preheated raw material gas and raw water can be supplied to the catalyst layer 410 in a uniform distribution via the distribution plate 800. The raw material mixture is supplied to the catalyst layer 410, where hydrocarbons such as ethane, propane, and isobutane are converted to methane, and then a reformed gas mainly containing hydrogen can be formed by a steam reforming reaction. At this time, the catalyst layer 410 may contain catalysts such as nickel-based or ruthenium-based catalysts.

[0055] The reformed gas generated after passing through the catalyst layer 410 flows into the reformed gas discharge pipe 500, moves upward, and can be discharged to the outside through the reformed gas outlet 510 provided on one side of the upper part of the reformed gas discharge pipe 500.

[0056] A fuel reformer according to yet another embodiment of the present invention may further include heat transfer fins 900. Figure 4 is a schematic diagram showing a configuration in which heat transfer fins are provided according to one embodiment of the present invention.

[0057] The heat transfer fins 900 may be formed in the shape of a partition wall on the outer surface of the combustion gas flow tube 300 in order to better supply heat to the catalyst layer 410 located between the combustion gas flow tube 300 and the reforming reaction tube 400.

[0058] The heat transfer fins 900 may include a plurality of heat transfer fins arranged at intervals along the outer surface of the combustion gas flow path pipe 300, as shown in Figure 4. Each of the plurality of heat transfer fins may be formed at a predetermined distance from adjacent heat transfer fins in the height direction.

[0059] The reason for having spaced-out areas between the heat transfer fins formed along the height of the combustion flow tube 300 is to minimize thermal deformation of the heat transfer fins caused by the combustion gas flowing through the gas supply tube 200 and the gas flow tube 300. If thermal deformation of the heat transfer fins occurs due to the combustion gas, it may become difficult to maintain the distance between the combustion gas flow tube 300 and the reforming reaction tube 400 due to the deformation of the shape of the heat transfer fins. This may result in uneven distribution of the reactants and make it difficult to ensure the reproducibility of operating performance.

[0060] As described above, the fuel reformer of the present invention, by providing a bellows tube 700 and a plurality of distribution plates, can significantly reduce the temperature deviation at the outlet of the reforming reaction tube 400 compared to conventional designs.

[0061] In one experimental example, a conventional fuel reformer having a heat exchange section and composed of a single distribution plate was compared with the fuel reformer according to the present invention. The results showed that the outlet temperature deviation of the reforming reaction tube in the conventional fuel reformer was 55°C, while the outlet temperature deviation of the reforming reaction tube in the fuel reformer according to the present invention was 20°C. In this experiment, the temperature deviation was measured using four thermometers placed at 90° intervals at the bottom of the cylindrical reforming reaction tube 400.

[0062] Furthermore, in the case of equilibrium attainment (△TR*), while the equilibrium attainment of conventional fuel reformers is 57°C, it was measured that the equilibrium attainment of the fuel reformer according to the present invention is 7°C. According to many existing research results, designing a fuel reformer so that the equilibrium attainment reaches 5-20°C is good from the viewpoint of fuel efficiency.

[0063] Furthermore, while the thermal efficiency of conventional fuel reformers was confirmed to be 75.7% based on the LHV (Lower Heat Value) standard, the thermal efficiency of the fuel reformer according to the present invention was 77.1%, an increase of approximately 1.4% compared to conventional models.

[0064] The above description of the present invention is illustrative, and a person with ordinary skill in the art to which the invention pertains will understand that it can be easily modified into other specific forms without altering the technical idea or essential features of the invention. Accordingly, the embodiments described above are illustrative in all respects and not limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined manner.

[0065] The scope of the present invention is defined by the claims described below, and all modified or altered forms derived from the meaning and scope of the claims, as well as the concept of equivalents thereof, are included within the scope of the present invention.

Claims

1. A combustion gas supply pipe is located in the center of the fuel reformer, forming a space in which a heat source can be placed, A combustion gas flow path pipe is formed to be longer than the length of the combustion gas supply pipe, so that the combustion gas generated from the heat source flows into the interior through a lower part that can communicate with the combustion gas supply pipe, A reforming reaction tube having a larger diameter than the aforementioned combustion gas flow path tube and having a catalyst layer inside, Located at the top of the reforming reaction tube, it is formed in a double helix shape and includes a bellows tube that is supplied with raw material gas and raw material water together, and discharges the preheated raw material gas and raw material water back into the reforming reaction tube. A fuel reformer characterized by the following features.

2. The aforementioned bellows tube is It is formed in a double helix shape surrounding the aforementioned combustion gas flow path pipe, It includes raw material gas inlets located at opposite positions on the upper part, and raw material gas outlets located at opposite positions on the lower part. The fuel reformer according to claim 1.

3. The heat exchange tube further includes a space in which the bellows tube can be arranged, and a passage formed inside through which the combustion gas flowing in from the combustion gas flow channel tube can pass. The fuel reformer according to claim 1.

4. The heat exchange tube is A ventilation hole is formed on the lower inner side, allowing combustion gas that has passed through the combustion gas flow path pipe to flow in, and a combustion gas outlet is formed on the upper outer side. The fuel reformer according to claim 3.

5. The reforming reaction tube further includes a distribution plate formed on a flow path toward the catalyst layer, which guides the preheated raw material gas and raw material water discharged from the bellows tube to be supplied to the catalyst layer uniformly. The fuel reformer according to claim 1.

6. The aforementioned distribution board is The first distribution board and A second distribution plate located below the first distribution plate, The system includes a third distribution plate located below the second distribution plate, The second distribution plate is positioned at an angle of axial rotation of 15° to 30° relative to the first and third distribution plates. The fuel reformer according to claim 5.

7. To supply heat to the catalyst layer formed between the combustion gas flow channel and the reforming reaction tube, the combustion gas flow channel further includes heat transfer fins formed in a partition-like manner on the outer surface of the combustion gas flow channel. The fuel reformer according to claim 1.

8. The heat transfer fins include a plurality of heat transfer fins provided at intervals along the outer surface of the combustion gas flow path tube, Each of the aforementioned heat transfer fins is formed with a predetermined distance between it and adjacent heat transfer fins in the height direction. The fuel reformer according to claim 7.

9. The reformed gas discharge pipe is further formed in a shape that surrounds the reformed reaction pipe, through which the reformed gas flows into the interior via a lower section that can communicate with the reformed reaction pipe, and has a reformed gas discharge port formed on the upper outer side from which the reformed gas is discharged. The fuel reformer according to claim 1.

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