Steam generation device, and fuel cell system including same

Abstract

Disclosed in the present invention are a steam generation device and a fuel cell system including same. The steam generation device comprises: a steam generation unit that receives reformed water to generate steam; and a buffer unit that alleviates a pressure change of the steam discharged from the steam generation unit.

Description

Steam generator and fuel cell system including same

[0001] The present invention relates to a steam generating device that supplies steam to a fuel reforming device that reforms hydrocarbon fuel, and a fuel cell system including the same.

[0002] Fuel cells generate electricity through the reaction of hydrogen and oxygen. In fuel cells, hydrocarbon fuels, such as city gas, are reformed externally to produce some hydrogen, which is then used as fuel for the fuel cell. Fuel cells are most efficient when hydrogen is used directly as fuel. However, this requires the hydrogen storage tank to be installed directly at the fuel cell site, which can pose serious safety issues. Therefore, fuel cells that operate at relatively high temperatures typically reform hydrocarbon fuels within the fuel cell system to produce hydrogen, which is then used as fuel for the fuel cell.

[0003] Steam reforming, a commonly used method for reforming hydrocarbon fuels, involves reacting steam with the hydrocarbon fuel to produce hydrogen. Steam reforming primarily produces hydrogen, carbon monoxide, and carbon dioxide through the reaction between steam and the hydrocarbon fuel, which are then supplied as fuel gas to the fuel cell.

[0004] However, in this steam reforming method, if a surge occurs due to a phase change in the reforming water in the steam generating device, the amount of steam supplied to the reforming device becomes uneven, and as a result, the fuel gas supplied to the fuel cell stack becomes uneven, which may cause a decrease in the power generation efficiency of the fuel cell stack and damage to the fuel cell stack.

[0005] One object of the present invention is to provide a steam generating device capable of stably and uniformly providing steam to a fuel reforming device.

[0006] Another object of the present invention is to provide a fuel cell system including the above steam generating device.

[0007] A steam generating device according to an embodiment of the present invention may include a steam generating unit that receives reformed water and generates steam; and a buffer unit that alleviates pressure changes in steam discharged from the steam generating unit.

[0008] In one embodiment, the buffer unit may include: an inlet portion connected to an outlet of the steam generation unit; a buffer portion connected to the inlet portion and forming a buffer space having a cross-sectional area larger than a cross-sectional area of ​​an internal space of the inlet portion; and an outlet portion connected to the buffer portion so as to face the inlet portion.

[0009] In one embodiment, the buffer section may further include one or more guide baffles disposed inside the buffer space and configured to increase the length of the steam movement path or reduce the cross-sectional area of ​​the path.

[0010] In one embodiment, the guide partition wall includes a first guide partition wall and a second guide partition wall spaced apart from each other within the buffer space, and a plurality of through holes may be formed independently in each of the first and second guide partition walls.

[0011] In one embodiment, the aperture ratio of the through hole may be 10 to 40%.

[0012] In one embodiment, the guide partition wall may include a first guide partition wall disposed in the center portion of the buffer space and having a first through hole formed therein; a second guide partition wall disposed between the first guide partition wall and the first portion of the buffer portion connected to the inlet portion and having a second through hole formed therein; and a third guide partition wall disposed between the first guide partition wall and the second portion connected to the outlet portion and having one or more third through holes formed therein.

[0013] In one embodiment, the first through hole may be formed in a central portion of the first guide partition wall, and the second and third through holes may be formed adjacent to edges of the second and third guide partition walls, respectively.

[0014] In one embodiment, the opening ratio of the first through hole may be 2 to 6%, and the opening ratios of each of the second and third through holes may be 10 to 20%.

[0015] In one embodiment, the guide partition wall may further include a fourth guide partition wall disposed between the inlet portion and the second guide partition wall and having a fourth through hole formed in the center portion; and a fifth guide partition wall disposed between the outlet portion and the third guide partition wall and having a fifth through hole formed in the outer portion.

[0016] In one embodiment, the opening ratio of each of the fourth and fifth through holes may be 15 to 25%.

[0017] In one embodiment, the guide partition wall may include a first guide partition wall disposed in the center of the buffer space and having a portion corresponding to a first edge portion of the buffer space cut out to form a flow path; a second guide partition wall disposed between the first guide partition wall and a first portion of the buffer portion to which the inlet portion is connected and having a portion corresponding to a second edge portion of the buffer space opposite to the first edge portion cut out to form a flow path; and a third guide partition wall disposed between the first guide partition wall and a second portion to which the outlet portion is connected and having a portion corresponding to a second edge portion of the buffer space opposite to the first edge portion cut out to form a flow path.

[0018] In one embodiment, the opening ratio by the cut portion of the first guide bulkhead may be 2 to 6%, and the opening ratio by the cut portion of each of the second and third guide bulkheads may be 10 to 20%.

[0019] In one embodiment, the guide partition wall may further include a fourth guide partition wall disposed between the inlet portion and the second guide partition wall, the fourth guide partition wall having a portion corresponding to the first edge portion of the buffer space cut out to form a flow path; and a fifth guide partition wall disposed between the outlet portion and the third guide partition wall, the fifth guide partition wall having a portion corresponding to the first edge portion of the buffer space cut out to form a flow path.

[0020] In one embodiment, the opening ratio by the cut portion of each of the fourth and fifth guide bulkheads may be 15 to 25%.

[0021] A fuel cell system according to an embodiment of the present invention includes a steam generating device that converts reformed water into steam; a reforming device that generates fuel gas containing hydrogen through a reforming reaction of hydrocarbon fuel using the steam; and a fuel cell stack that generates electricity using the fuel gas and air, wherein the steam generating device may include a steam generating unit that receives the reformed water and generates steam; and a buffer unit that alleviates pressure changes in steam discharged from the steam generating unit and supplies the steam to the reforming device.

[0022] In one embodiment, the buffer unit may include: an inlet portion connected to an outlet of the steam generation unit; a buffer portion connected to the inlet portion and forming a buffer space having a cross-sectional area larger than a cross-sectional area of ​​an internal space of the inlet portion; and an outlet portion arranged to face the inlet portion and connecting the buffer portion and the reforming device.

[0023] In one embodiment, the buffer section may further include one or more guide baffles disposed inside the buffer space and configured to increase the length of the steam movement path or reduce the cross-sectional area of ​​the path.

[0024] In one embodiment, the guide partition wall includes a first guide partition wall and a second guide partition wall spaced apart from each other within the buffer space, and a plurality of through holes may be formed independently in each of the first and second guide partition walls.

[0025] In one embodiment, the aperture ratio of the through hole may be 10 to 40%.

[0026] In one embodiment, the guide partition wall may include a first guide partition wall disposed in the center portion of the buffer space and having a first through hole formed therein; a second guide partition wall disposed between the first guide partition wall and the first portion of the buffer portion connected to the inlet portion and having a second through hole formed therein; and a third guide partition wall disposed between the first guide partition wall and the second portion connected to the outlet portion and having one or more third through holes formed therein.

[0027] In one embodiment, the first through hole may be formed in a central portion of the first guide partition wall, and the second and third through holes may be formed adjacent to edges of the second and third guide partition walls, respectively.

[0028] In one embodiment, the opening ratio of the first through hole may be 2 to 6%, and the opening ratios of each of the second and third through holes may be 10 to 20%.

[0029] In one embodiment, the guide partition wall may further include a fourth guide partition wall disposed between the inlet portion and the second guide partition wall and having a fourth through hole formed in the center portion; and a fifth guide partition wall disposed between the outlet portion and the third guide partition wall and having a fifth through hole formed in the outer portion.

[0030] In one embodiment, the guide partition wall may include a first guide partition wall disposed in the center of the buffer space and having a portion corresponding to a first edge portion of the buffer space cut out to form a flow path; a second guide partition wall disposed between the first guide partition wall and a first portion of the buffer portion to which the inlet portion is connected and having a portion corresponding to a second edge portion of the buffer space opposite to the first edge portion cut out to form a flow path; and a third guide partition wall disposed between the first guide partition wall and a second portion to which the outlet portion is connected and having a portion corresponding to a second edge portion of the buffer space opposite to the first edge portion cut out to form a flow path.

[0031] In one embodiment, the guide partition wall may further include a fourth guide partition wall disposed between the inlet portion and the second guide partition wall, the fourth guide partition wall having a portion corresponding to the first edge portion of the buffer space cut out to form a flow path; and a fifth guide partition wall disposed between the outlet portion and the third guide partition wall, the fifth guide partition wall having a portion corresponding to the first edge portion of the buffer space cut out to form a flow path.

[0032] According to the steam generating device of the present invention, pressure changes in steam can be alleviated through a buffer unit connected to the outlet of the steam generating unit, thereby improving reforming performance in the reforming device, and as a result, improving the power generation efficiency of the fuel cell stack.

[0033] FIG. 1 is a drawing for explaining a steam generating device according to an embodiment of the present invention.

[0034] FIG. 2a and FIG. 2b are drawings for explaining one embodiment of the buffer unit shown in FIG. 1 and the guide bulkhead applied thereto, respectively.

[0035] FIGS. 3A and 3B are drawings for explaining other embodiments of the buffer unit illustrated in FIG. 1 and the guide bulkhead applied thereto, respectively.

[0036] FIG. 4 is a drawing illustrating another embodiment of the buffer unit illustrated in FIG. 1.

[0037] FIGS. 5A and 5B are drawings for explaining another embodiment of the buffer unit illustrated in FIG. 1 and the guide bulkhead applied thereto, respectively.

[0038] FIG. 6 is a drawing illustrating another embodiment of the buffer unit illustrated in FIG. 1.

[0039] FIG. 7 is a drawing for explaining a fuel cell system according to an embodiment of the present invention.

[0040] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The present invention may be modified in various ways and may take various forms. Therefore, specific embodiments are illustrated in the drawings and described in detail in the text. However, this is not intended to limit the present invention to a specific disclosed form, but should be understood to include all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention. In describing each drawing, similar reference numerals are used to indicate similar components. In the attached drawings, the dimensions of structures are shown larger than actual size to ensure clarity of the present invention.

[0041] While terms like "first" and "second" may be used to describe various components, these components should not be limited by these terms. These terms are used solely to distinguish one component from another. For example, without departing from the scope of the present invention, a first component could be referred to as a "second component," and similarly, a second component could also be referred to as a "first component."

[0042] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, step, operation, component, part, or combination thereof described in the specification, but do not preclude the possibility of the presence or addition of one or more other features, steps, operations, components, parts, or combinations thereof.

[0043] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined herein.

[0044]

[0045] Steam Generator

[0046] FIG. 1 is a drawing for explaining a steam generator according to an embodiment of the present invention, FIGS. 2a and 2b are drawings for explaining one embodiment of the buffer unit illustrated in FIG. 1 and a guide partition wall applied thereto, respectively, FIGS. 3a, 3b, and 4 are drawings for explaining other embodiments of the buffer unit illustrated in FIG. 1 and a guide partition wall applied thereto, respectively, and FIGS. 5a, 5b, and 6 are drawings for explaining still other embodiments of the buffer unit illustrated in FIG. 1 and a guide partition wall applied thereto, respectively.

[0047] Referring to FIGS. 1 to 6, a steam generating device (1000) according to an embodiment of the present invention may include a steam generating unit (1100) that receives reformed water and generates steam; and a buffer unit (1200) that alleviates pressure changes in steam discharged from the steam generating unit (1100).

[0048] The above steam generation unit (1100) generates methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H 10 ), natural gas, coal gas, etc., can be used to generate steam necessary for producing hydrogen through a reforming reaction using steam from hydrocarbon fuels that chemically contain hydrogen. In one example, when methane (CH4) is supplied as the hydrocarbon fuel, hydrogen can be produced by reacting methane and steam according to the following reaction formula 1 inside a reforming device (see '12000' in FIG. 5) to be described below.

[0049] [Reaction Formula 1]

[0050]

[0051] Along with the above reaction, a side reaction that generates carbon (C) may occur inside the reformer, as shown in the following reaction formula 2, depending on the reaction temperature, the ratio of steam and carbon components, etc., and if the carbon generated by the side reaction is supplied to the fuel cell stack, it may cause a problem of damaging the fuel electrode of the fuel cell, thereby drastically reducing the performance of the fuel cell. Therefore, in order to suppress the above carbon generation side reaction, high-temperature steam must be stably supplied to the reformer.

[0052] [Reaction Formula 2]

[0053]

[0054] If the above steam can be generated, the configuration of the steam generation unit (1100) is not particularly limited.

[0055] In one embodiment, the steam generation unit (1100) may include a container (1110), a space partition member (1120), and a vaporization tube (1140). Meanwhile, the steam generation unit (1100) may further include a preheating member (1130).

[0056] The container (1110) may have an internal space (1001, 1002), and the space partition member (1120) may be arranged inside the container (1110) to divide the internal space (1001, 1002) of the container (1110) into two spaces, i.e., a steam discharge space (1001) and a heating space (1002). In addition, a steam discharge port (1111) through which steam is discharged may be formed in a portion of the container (1110) that forms the steam discharge space (1001), and this steam discharge port (1111) may be connected to the buffer unit (1200).

[0057] The container (1110) and the space partition member (1120) may be formed of a material that is stable at high temperatures. For example, the container (1110) and the space partition member (1120) may be independently formed of a material that is stable at high temperatures, such as a metal, alloy, ceramic, metal composite, or composite of metal and ceramic. Meanwhile, the container (1110) and the space partition member (1120) may be formed of the same material or may be formed of different materials.

[0058] In one embodiment, the steam discharge space (1001) may include a first space (1001a) directly connected to the steam discharge port (1111) and a second space (1001b) located below the first space (1001a) and temporarily storing water that has not been converted into steam or has been generated by cooling the steam, and the water stored in the second space (1001b) may be converted into steam by thermal energy supplied to the heating space (1002). In order to effectively supply the thermal energy provided to the heating space (1002) to the water stored in the second space (1001b), the second space (1001b) may be formed such that the upper side is connected to the first space (1001a) and the side and / or bottom are surrounded by the heating space (1002). In this way, the shape of the second space (1001b) is not particularly limited as long as it can accommodate the water and effectively receive thermal energy from the heating space (1002). For example, the second space (1001b) may have a shape such as a cylinder, a square column, a cone, or a square pyramid, the sides of which are surrounded by the heating space (1002).

[0059] In one embodiment, in order to form the first space (1001a) and the second space (1001b), the space partition member (1120) may include a first partition portion (1121) and a second partition portion (1122). The first partition portion (1121) has an opening portion of a predetermined shape formed in the center portion, is coupled to a side wall of the container (1110), and may partition the first space (1001a) and the heating space (1002). The second partition portion (1122) may extend downward from the opening portion of the first partition portion (1121) to form the second space (1001b), and may partition the second space (1001b) and the heating space (1002).

[0060] In one embodiment, the space partition member (1120) may include a plurality of guide protrusions (1123) protruding from the surface of the second partition (1122) toward the vaporization tube (1140). The guide protrusions (1123) may support the lower portion of the vaporization tube (1140) to guide and maintain the arrangement position of the vaporization tube (1140).

[0061] The above preheating member (1130) can receive water from an external water supply device (not shown) and preheat it, and supply the preheated water or water vapor to the vaporization tube (1140).

[0062] In one embodiment, the preheating member (1130) may include a chamber (1131), a plurality of baffles (1132), an inlet (1133) and an outlet (1134).

[0063] The above chamber (1131) is arranged on the bottom surface of the heating space (1002) inside the container (1110) and can provide a preheating space that receives and preheats water supplied from an external water supply device (not shown).

[0064] The above plurality of bevels (1132) are arranged inside the preheating space of the chamber (1131), so as to increase the length of the flow path of water or steam moving through the preheating space, and reduce or prevent back pressure from occurring within the preheating space.

[0065] In one embodiment, the plurality of baffles (1132) may include one or more first baffles protruding downward from the upper surface of the chamber (1131) forming the upper surface of the preheating space and one or more second baffles protruding upward from the lower surface of the chamber (1131) forming the lower surface of the preheating space, and the first and second baffles may be arranged alternately. The height, spacing, number, position, etc. of the first and second baffles are not particularly limited and may be appropriately adjusted according to the required performance. For example, the first and second baffles may be uniformly arranged inside the chamber, arranged at a position closer to the inlet (1133) than to the outlet (1134), or arranged at a position closer to the outlet (1134) than to the inlet (1133).

[0066] The above inlet (1133) can connect the preheating space of the chamber (1131) and the external water supply device (not shown), and the above outlet (1134) can connect the preheating space of the chamber (1131) and the vaporization tube (1140).

[0067] In one embodiment, to increase the length of the flow path within the preheating space, the inlet (1133) may be formed adjacent to a first end side of the chamber (1131), and the outlet (1134) may be formed adjacent to a second end side of the chamber (1131) opposite to the first end.

[0068] The above vaporization tube (1140) may be arranged in a coil shape surrounding the second space (1001b) within the heating space (1002). The vaporization tube (1140) has a first end connected to the discharge port (1134) of the preheating member (1130) and a second end positioned within the steam discharge space (1001), and may be arranged to extend to the steam discharge space (1001) via the heating space (1002).

[0069] When the vaporization tube (1140) is installed as described above, water supplied from the preheating member (1130) to the vaporization tube (1140) can be converted into steam while moving through the heating space (20), and the converted steam can be discharged into the steam discharge space (1001) through the second end of the vaporization tube (1140). In addition, the steam discharged from the vaporization tube (1140) into the steam discharge space (1001) can be supplied to the buffer unit (1200) through the steam discharge port (1111).

[0070] The buffer unit (1200) can receive steam discharged from the steam generation unit (1100) and alleviate the pressure change thereof to supply it to the reforming device (see '12000' of FIG. 7). The amount of steam supplied to the reforming device becomes irregular due to the occurrence of a surge pressure caused by a phase change of the reforming water inside the steam generation unit (1100) and the change in the amount of reforming water supplied according to the operation of the reforming water supply pump. As a result, the amount of reforming fuel gas supplied to the fuel cell stack (see '13000' of FIG. 7) also becomes irregular, which may cause a problem of causing an incomplete reaction or damage to the fuel cell stack. However, in the present invention, the pressure change of water vapor caused by the occurrence of a surge due to a phase change in the reformed water, the flow of the reformed water supply amount due to the operation of the reformed water supply pump, etc. is alleviated through the buffer unit (1200) and then supplied to the reforming device, thereby solving the above-described problem.

[0071] In one embodiment, the buffer unit (1200) may include an inlet portion (1210), a buffer portion (1220), and an outlet portion (1230).

[0072] The above inlet portion (1210) can be connected to the outlet (1111) of the steam generation unit (1100), and an inlet path through which steam can move can be formed inside.

[0073] The buffer section (1220) may be connected to the inlet section (1210) and form a buffer space having a cross-sectional area larger than the cross-sectional area of ​​the inlet passage formed inside the inlet section (1210). The maximum cross-sectional area of ​​the buffer space may be about 3 to 15 times larger than the cross-sectional area of ​​the inlet passage. The buffer space may be formed to have a constant diameter, but may also be formed to have a diameter that varies depending on the location. For example, the diameter of the central portion of the buffer space may be larger than the diameter of the portion adjacent to the inlet section (1210) and the withdrawal section (1230).

[0074] The above-described withdrawal portion (1230) may be connected to the buffer portion (1220) so as to face the above-described introduction portion (1210). For example, a withdrawal path connected to the buffer space may be formed inside the withdrawal portion (1230), and the diameter of the withdrawal path may be the same as or similar to the diameter of the introduction path. For example, the diameter of the withdrawal path may be about 70 to 120%, or about 80 to 110%, of the diameter of the introduction path.

[0075] In this way, when a buffer unit (1200) having a buffer space having a relatively large cross-sectional area with respect to the direction of movement of water vapor is connected to the outlet (1111) of the water vapor generation unit (1100), the movement speed of the water vapor can be rapidly reduced according to the following equation 3, and as a result, the pressure change of the water vapor caused by the water vapor generation unit (1100) and / or the reformed water supply pump supplying reformed water to the water vapor generation unit (1100) can be significantly reduced.

[0076] [Formula 3]

[0077] V=Q / A

[0078] In the above equation 3, V represents the velocity of water vapor, Q represents the flow rate of water vapor, and A represents the cross-sectional area of ​​the water vapor path.

[0079] In one embodiment, the buffer unit (1200) may further include one or more guide partitions (1240) arranged inside the buffer space.

[0080] In one embodiment, as illustrated in FIGS. 2a and 2b, the guide partition wall (1240) may include a first guide partition wall (1240a) and a second guide partition wall (1240b) that are spaced apart from each other within the buffer space. In this case, a plurality of through holes (1241a, 1241b) may be formed independently in each of the first and second guide partition walls (1240a, 1240b). By changing the size of each of the through holes (1241a, 1241b) and the opening ratio of the through holes (1241a, 1241b), the effect of alleviating the pressure change of water vapor can be controlled. In one embodiment, the diameter of the through holes (1241a, 1241b) may be about 2 to 4 cm, and the opening ratio by the through holes (1241a, 1241b) may be about 10 to 40%.

[0081] In another embodiment, as illustrated in FIGS. 3a and 3b, the guide partition wall (1240-1) may include a first guide partition wall (1240a-1), a second guide partition wall (1240b-1), and a third guide partition wall (1240c-1) that are spaced apart from each other within the buffer space. In this case, the first guide partition wall (1240a-1) may be disposed in a central portion of the buffer space, and the second guide partition wall (1240b-1) and the third guide partition wall (1240c-1) may be disposed between the first guide partition wall (1240a-1) and the inlet portion (1210-1) and between the first guide partition wall (1240a-1) and the outlet portion (1230-1), respectively. The first guide partition wall (1240a-1) may have a first through hole (1241a-1) formed in the center portion, the second guide partition wall (1240b-1) may have one or more, for example, a plurality of second through holes (1241b-1) formed in the edge portion, and the third guide partition wall (1240c-1) may have one or more, for example, a plurality of third through holes (1241c-1) formed in the edge portion. For example, each of the second and third through holes (1241b-1, 1241c-1) may be formed in the edge portions of the second and third guide partition walls (1240b-1, 1240c-1) so as not to overlap with the first through hole (1241a-1) or to overlap with a portion thereof, for example, an area ratio of 10% or less.

[0082] In one embodiment, the opening ratio of the first through hole (1240a-1) may be smaller than the opening ratios of each of the second and third through holes (1240b-1, 1240c-1). For example, the opening ratio of the first through hole (1240a-1) may be about 2 to 6%, for example, about 3 to 5%, and the opening ratio of each of the second and third through holes (1240b-1, 1240c-1) may be about 10 to 20%, for example, about 13 to 17%.

[0083] Meanwhile, unlike that illustrated in FIG. 3b, the first guide partition wall (1240a-1) may have a plurality of first through holes (1241a-1) arranged along the edge portion, and the second and third guide partition walls (1240b, 1240c) may have second and third through holes (1241b, 1241c) formed in the center portion, respectively.

[0084] In another embodiment, as illustrated in FIG. 4, the guide partition wall (1240-2) may further include a fourth guide partition wall (1240d-2) positioned adjacent to the inlet portion (1210-2) and a fifth guide partition wall (1240e-2) positioned adjacent to the outlet portion (1230), in addition to the first to third guide partition walls (1240a-2, 1240b-2, 1240c-2) having the same structure as illustrated in FIGS. 3a and 3b. Fourth and fifth through holes may be formed in the central portions of each of the fourth and fifth guide partition walls (1240d-2, 1240e-2), respectively.

[0085] In one embodiment, the opening ratio of each of the fourth and fifth through holes may be greater than the opening ratio of each of the first to third through holes. For example, the opening ratio of the first through hole may be about 2 to 6%, for example, about 3 to 5%, the opening ratio of each of the second and third through holes may be about 10 to 20%, for example, about 13 to 17%, and the opening ratio of each of the fourth and fifth through holes may be about 15 to 25%, for example, about 18 to 22%.

[0086] In another embodiment, as illustrated in FIGS. 5a and 5b, the guide partition wall (1240) may include a first guide partition wall (1240a-3), a second guide partition wall (1240b-3), and a third guide partition wall (1240c-3) which are spaced apart from each other within the buffer space. In this case, the first guide partition wall (1240a-3) may be disposed in a central portion of the buffer space, and the second guide partition wall (1240b-3) and the third guide partition wall (1240c-3) may be disposed between the first guide partition wall (1240a-3) and the inlet portion (1210-3) and between the first guide partition wall (1240a-3) and the outlet portion (1230-3), respectively. The first guide partition wall (1240a-3) may have a baffle structure in which a portion corresponding to the first edge portion of the buffer space is cut out so as to form a passage through which water vapor can move in the first edge portion of the buffer space, and each of the second and third guide partition walls (1240b-3, 1240c-3) may have a baffle structure in which a portion corresponding to the second edge portion of the buffer space is cut out so as to form a passage through which water vapor can move in the second edge portion of the buffer space opposite to the first edge portion. In this way, when the first to third guide partition walls (1240a-3, 1240b-3, 1240c-3) have a baffle structure, an increase in pressure in the buffer space caused by blockage of the through hole can be prevented.

[0087] In one embodiment, the opening ratio by the cut portion of the first guide partition wall (1240a-3) may be smaller than the opening ratio by the cut portion of each of the second and third guide partition walls (1240b-3, 1240c-3). For example, the opening ratio by the cut portion of the first guide partition wall (1240a-3) may be about 2 to 6%, for example, about 3 to 5%, and the opening ratio by the cut portion of each of the second and third guide partition walls (1240b-3, 1240c-3) may be about 10 to 20%, for example, about 13 to 17%.

[0088] In another embodiment, as illustrated in FIG. 6, the guide partition wall (1240-4) may further include a fourth guide partition wall (1240d-4) positioned adjacent to the inlet portion (1210-4) and a fifth guide partition wall (1240e-4) positioned adjacent to the outlet portion (1230-4), in addition to the first to third guide partition walls (1240a-4, 1240b-4, 1240c-4) having the same structure as those illustrated in FIGS. 5a and 5b. In one embodiment, each of the fourth and fifth guide partition walls (1240d-4, 1240e-4) may have a baffle structure in which a portion corresponding to the first edge portion of the buffer space is cut out so as to form a path through which water vapor can move in the first edge portion of the buffer space in the same direction as the first guide partition wall (1240a-4).

[0089] In one embodiment, the opening ratio of the cut portion of each of the fourth and fifth guide partition walls (1240d-4, 1240e-4) may be greater than the opening ratio of the cut portion of each of the first to third guide partition walls (1240a-4, 1240b-4, 1240c-4). For example, the opening ratio by the cut portion of the first guide partition wall (1240a-4) may be about 2 to 6%, for example, about 3 to 5%, the opening ratio by the cut portion of each of the second and third guide partition walls (1240b-4, 1240c-4) may be about 10 to 20%, for example, about 13 to 17%, and the opening ratio by the cut portion of each of the fourth and fifth guide partition walls (1240d-4, 1240e-4) may be about 15 to 25%, for example, about 18 to 22%.

[0090]

[0091] Meanwhile, the inlet portion (1210) may include a first fastening mechanism for coupling with a first pipe extended from an outlet (1111) of the steam generation unit (1100), and the outlet portion (1230) may include a second fastening mechanism for coupling with a second pipe extended from a reforming device.

[0092]

[0093] According to the steam generation device of the present invention, pressure changes in steam can be alleviated through a buffer unit (1200) connected to an outlet (1111) of the steam generation unit (1100), so that reforming performance in a reforming device can be improved, and as a result, power generation efficiency of a fuel cell stack can be improved.

[0094]

[0095] Fuel Cell System

[0096] FIG. 5 is a drawing for explaining a fuel cell system according to an embodiment of the present invention.

[0097] Referring to FIG. 5 along with FIGS. 1 to 4, a fuel cell system (10000) according to an embodiment of the present invention may include a steam generator (11000), a reformer (12000), a fuel cell stack (13000), and a combustor (14000).

[0098] The above steam generator (11000) can receive reformed water from an external water supply device (not shown), convert it into steam, and then supply it to the reformer (12000). As the steam generator (11000), the steam generator (1000) described with reference to FIGS. 1 to 4 can be applied, and therefore, a detailed description thereof will be omitted.

[0099] The above reforming device (12000) can generate fuel gas containing hydrogen by reacting hydrocarbon fuel supplied from an external fuel supply device (not shown) and steam supplied from the steam generator (11000). Since any known fuel reforming device can be applied without limitation to the reforming device (12000), a detailed description thereof will be omitted.

[0100] The above fuel cell stack (13000) can generate electricity using hydrogen in the fuel gas provided from the reformer (12000) and oxygen in the air provided from an external air supply device (not shown). As the fuel cell stack (13000), a solid oxide fuel cell stack, a solid polymer fuel cell stack, a phosphoric acid fuel cell stack, a molten carbonate fuel cell stack, etc. can be applied without limitation.

[0101] The above combustor (14000) can generate high-temperature combustion gas by combusting the anode off-gas and cathode off-gas discharged from the fuel cell stack (13000), and can supply the high-temperature combustion gas to the heating space (see '1002' of FIG. 1) of the steam generating device (11000). In addition, the combustor (14000) can supply thermal energy required for the reaction between the hydrocarbon fuel and the steam to the reforming device (12000). Any known combustion device can be applied as the combustor (14000) without limitation.

[0102]

[0103] Although the present invention has been described above with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various modifications and changes may be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below.

Claims

1. A steam generation unit that receives reformed water and generates steam; and A steam generating device, comprising a buffer unit that alleviates pressure changes in steam discharged from the steam generating unit.

2. In paragraph 1, The above buffer unit, An inlet connected to the outlet of the above steam generating unit; A buffer part connected to the above introduction part and forming a buffer space having a cross-sectional area larger than the cross-sectional area of the internal space of the above introduction part; and A steam generating device, comprising: an outlet connected to the buffer portion so as to face the inlet portion; 3. In paragraph 2, A steam generating device, wherein the buffer section is arranged inside the buffer space and further includes one or more guide baffles that increase the length of the steam movement path or reduce the cross-sectional area of the path.

4. In paragraph 3, The above guide bulkhead includes a first guide bulkhead and a second guide bulkhead which are spaced apart from each other within the buffer space, A steam generating device, wherein a plurality of penetration holes are formed independently in each of the first and second guide bulkheads.

5. In paragraph 4, A steam generating device, wherein the opening ratio of the above through hole is 10 to 40%.

6. In paragraph 3, The above guide bulkhead is, A first guide bulkhead positioned in the center of the above buffer space and having a first through hole formed therein; A second guide bulkhead is disposed between the first guide bulkhead and the first part of the buffer section to which the inlet section is connected, and has a second through hole formed therein; and A steam generator comprising a third guide baffle disposed between the first guide baffle and the second portion to which the withdrawal portion is connected, and having at least one third through hole formed therein.

7. In paragraph 6, The above first through hole is formed in the center portion of the first guide bulkhead, A steam generating device, wherein each of the second and third through holes is formed adjacent to an edge of each of the second and third guide bulkheads.

8. In paragraph 7, The opening ratio of the first through hole is 2 to 6%, A steam generating device, wherein the opening ratio of each of the second and third through holes is 10 to 20%.

9. In paragraph 7, A steam generator, wherein the guide baffle further includes a fourth guide baffle disposed between the inlet portion and the second guide baffle and having a fourth through hole formed in the center portion; and a fifth guide baffle disposed between the outlet portion and the third guide baffle and having a fifth through hole formed in the center portion.

10. In paragraph 3, A steam generating device, wherein the opening ratio of each of the fourth and fifth through holes is 15 to 25%.

11. In paragraph 3, The above guide bulkhead is, A first guide bulkhead positioned in the center of the buffer space and having a portion corresponding to the first edge of the buffer space cut to form a flow path; A second guide partition, which is arranged between the first guide partition and the first part of the buffer section to which the inlet is connected, and in which a portion corresponding to the second edge part of the buffer space opposite to the first edge part is cut to form a flow path; and A steam generator, comprising: a third guide baffle disposed between the first guide baffle and the second portion to which the withdrawal portion is connected, the third guide baffle having a portion corresponding to the second edge portion of the buffer space opposite to the first edge portion cut to form a flow path; 12. In paragraph 11, The opening ratio by the cut portion of the first guide bulkhead is 2 to 6%, A steam generating device, wherein the opening ratio of each of the cut portions of the second and third guide bulkheads is 10 to 20%.

13. In paragraph 11, A steam generator, wherein the guide baffle further includes: a fourth guide baffle disposed between the inlet portion and the second guide baffle, the portion corresponding to the first edge portion of the buffer space being cut to form a flow path; and a fifth guide baffle disposed between the outlet portion and the third guide baffle, the portion corresponding to the first edge portion of the buffer space being cut to form a flow path.

14. In paragraph 13, A steam generating device, wherein the opening ratio of each of the cut portions of the fourth and fifth guide bulkheads is 15 to 25%.

15. A steam generator that converts reformed water into steam; A reforming device that generates fuel gas containing hydrogen through a reforming reaction of hydrocarbon fuel using the above steam; and It includes a fuel cell stack that generates electricity using the fuel gas and air, The above steam generating device is, A steam generation unit that receives the above reformed water and generates steam; and A fuel cell system, comprising a buffer unit that alleviates pressure changes in steam discharged from the steam generation unit and supplies the steam to the reforming device.

16. In paragraph 15, The above buffer unit, An inlet connected to the outlet of the above steam generating unit; A buffer part connected to the above introduction part and forming a buffer space having a cross-sectional area larger than the cross-sectional area of the internal space of the above introduction part; and A fuel cell system, comprising: an outlet portion positioned opposite to the inlet portion and connecting the buffer portion and the reforming device; 17. In paragraph 16, A fuel cell system, wherein the buffer section further includes one or more guide baffles arranged inside the buffer space and configured to increase the length of the vapor movement path or reduce the cross-sectional area of the path.

18. In paragraph 17, The above guide bulkhead includes a first guide bulkhead and a second guide bulkhead which are spaced apart from each other within the buffer space, A fuel cell system, wherein a plurality of penetration holes are formed independently in each of the first and second guide bulkheads.

19. In paragraph 18, A fuel cell system, wherein the aperture ratio of the above through hole is 10 to 40%.

20. In paragraph 16, The above guide bulkhead is, A first guide bulkhead positioned in the center of the above buffer space and having a first through hole formed therein; A second guide bulkhead is disposed between the first guide bulkhead and the first part of the buffer section to which the inlet section is connected, and has a second through hole formed therein; and A fuel cell system comprising a third guide bulkhead, which is disposed between the first guide bulkhead and the second portion to which the withdrawal portion is connected, and in which at least one third through hole is formed.

21. In paragraph 20, The above first through hole is formed in the center portion of the first guide bulkhead, A fuel cell system, wherein each of the second and third through holes is formed adjacent to an edge of each of the second and third guide bulkheads.

22. In paragraph 21, The opening ratio of the first through hole is 2 to 6%, A fuel cell system, wherein each of the second and third through holes has an opening ratio of 10 to 20%.

23. In paragraph 20, A fuel cell system, wherein the guide bulkhead further includes: a fourth guide bulkhead disposed between the inlet portion and the second guide bulkhead and having a fourth through hole formed in the center portion; and a fifth guide bulkhead disposed between the outlet portion and the third guide bulkhead and having a fifth through hole formed in the outer portion.

24. In paragraph 16, The above guide bulkhead is, A first guide bulkhead positioned in the center of the buffer space and having a portion corresponding to the first edge of the buffer space cut to form a flow path; A second guide partition, which is arranged between the first guide partition and the first part of the buffer section to which the inlet is connected, and in which a portion corresponding to the second edge part of the buffer space opposite to the first edge part is cut to form a flow path; and A fuel cell system, comprising: a third guide bulkhead, which is disposed between the first guide bulkhead and the second portion to which the withdrawal portion is connected, and in which a portion corresponding to a second edge portion of the buffer space opposite to the first edge portion is cut to form a flow path; 25. In paragraph 24, A fuel cell system, wherein the guide partition further includes: a fourth guide partition arranged between the inlet portion and the second guide partition, the fourth guide partition having a portion corresponding to the first edge portion of the buffer space cut out to form a flow path; and a fifth guide partition arranged between the outlet portion and the third guide partition, the fifth guide partition having a portion corresponding to the first edge portion of the buffer space cut out to form a flow path.

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