Fuel cell device

Abstract

Fuel cell device comprising the following: a reformer (302) that reforms a crude fuel to produce a reformed fuel; a fuel cell stack (CS) that is supplied with the reformed fuel and an oxidant and generates power; a combustion engine (20) that burns the reformed fuel discharged from the fuel cell stack (CS) in order to heat the reformer (302); and a housing (10) in which the fuel cell stack (CS), the reformer (302) and the combustion unit (20) are accommodated; and a blocking plate (BP) that blocks the air supplied to the fuel cell stack (CS) to generate power and the combustion exhaust gas generated in the combustion chamber (20) in such a way that the air and the combustion exhaust gas do not flow out and into each other, wherein the reformer (302) and the combustion chamber (20) are arranged in a position that does not directly receive radiant heat from the fuel cell stack (CS), wherein the housing (10) has arranged the blocking plate (BP) along a horizontal plane in the housing (10), wherein the fuel cell stack (CS) is arranged above the blocking plate (BP) and wherein the reformer (302) and the combustion chamber (20) are arranged below the blocking plate (BP), characterized by the fact that the combustion engine (20) is arranged in a central position of the housing (10) when viewed from above and the reformer (302) is arranged in such a way that it surrounds the combustion chamber (20) from the side.

Description

Technical field

[0001] The present invention relates to a fuel cell device. Background technology

[0002] A fuel cell device is a power generation device that directly converts chemical energy, held by fuel and an oxidant, into electrical energy. The fuel cell device has a very high power conversion efficiency, and the gas emitted by the fuel cell is comparatively clean. Consequently, the fuel cell device has received attention as a next-generation power generation device.

[0003] Hydrogen is used as a fuel, but a hydrogen infrastructure is currently not adequately developed. For this reason, the fuel cell device is generally equipped with a reformer that reforms raw fuel (town gas, LPG, or similar) obtained from an existing infrastructure to produce hydrogen. The reformer contains a reforming catalyst. Inside the reformer, the raw fuel and water vapor supplied to it are brought into contact with the reforming catalyst at high temperature to initiate a reforming reaction, thereby producing hydrogen. Gas containing the hydrogen is then fed from the reformer to a fuel cell stack (cell stack) as fuel.

[0004] To ensure a stable reforming reaction, the reforming catalyst and the raw fuel in the reformer must be kept at a high temperature. Therefore, a combustion chamber is located near the reformer to heat it externally. This chamber combusts, for example, the remaining fuel that is removed from the fuel pile, thereby heating the reformer with the heat generated by the combustion.

[0005] In the fuel cell device described in JP 2011-238 363 A, a reformer and a combustion chamber are arranged near a fuel cell stack. Furthermore, an air preheater for heating air (oxidizing agent) to be supplied to the fuel cell stack is also arranged near the fuel cell stack.

[0006] When the fuel cell device generates power, the fuel cell stack is heated to a high temperature by the heat of reaction. Therefore, in the fuel cell device described in JP 2011-238 363 A, radiant heat from the high-temperature fuel cell stack directly reaches the reformer, the combustion chamber, and the air preheater. The air is heated not only by the radiant heat from the combustion chamber but also by the radiant heat from the fuel cell stack, further increasing the energy utilization efficiency of the fuel cell. Furthermore, the reformer and the combustion chamber are arranged in the same housing as the housing containing the fuel cell stack, resulting in a compact overall design for the fuel cell device.

[0007] However, in the fuel cell device described in JP 2011-238 363 A, the radiant heat from the fuel cell stack also directly reaches the reformer, which is located adjacent to the combustion chamber. This reduces the heat transfer from the combustion chamber to the reformer, and consequently, the combustion chamber is heated more intensely. As a result, the oxidation of combustion chamber components, which are brought to excessively high temperatures, is accelerated, making rapid combustion chamber damage likely.

[0008] US Patent 2009 / 0280370A1 discloses a fuel cell device according to the preamble of claim 1, wherein an incinerator and a reformer are adjacent to the end plate of a fuel cell stack and the incinerator surrounds the reformer.

[0009] JP 2014-82 146 A discloses a fuel cell device according to the preamble of claim 2, wherein an internal combustion engine and a reformer are arranged side by side and surround a fuel cell stack. Summary of the invention

[0010] It is an object of the present invention to provide a fuel cell device that is compact as a whole and that can prevent an internal combustion engine from being damaged quickly.

[0011] According to one aspect of the present invention, the fuel cell device comprises the features of claim 1.

[0012] According to another aspect of the present invention, the fuel cell device comprises the features of claim 2.

[0013] In the fuel cell devices according to claims 1 and 2, the fuel cell stack, the reformer, and the combustion chamber are arranged in a single housing, thus making the entire assembly compact. Furthermore, in this configuration, the radiant heat from the fuel cell stack itself does not directly reach the reformer and the combustion chamber. The reformer is not directly heated by the radiant heat, and consequently, its temperature is not excessively increased. This reduces the heat transfer from the combustion chamber to the reformer, thereby preventing an excessive increase in the combustion chamber's temperature. As a result, it is possible to prevent the combustion chamber from being rapidly damaged by an excessive temperature rise.

[0014] According to the present disclosure, it is possible to provide a fuel cell device that can prevent the combustion engine from being damaged quickly. Brief description of the drawings Fig. Figure 1 is a schematic diagram to illustrate an internal structure of a fuel cell device according to an embodiment of the present disclosure. Fig. Figure 2 is a perspective view to depict the external appearance of a reforming unit. Fig. Figure 3 is a block diagram to illustrate the flows of gas and water in the fuel cell device. Fig. Figure 4 is a schematic view to illustrate radiation in the fuel cell device. Embodiments for carrying out the invention

[0015] An embodiment of the present invention is described below with reference to the accompanying drawings.

[0016] As in Fig. As shown in Figure 1, a fuel cell device FC comprises a fuel cell stack CS (cell stack), a housing 10, an internal combustion unit 20 and a reforming unit 30.

[0017] The CS fuel cell stack is an assembly of several (not shown) fuel cells. Each fuel cell is a solid oxide fuel cell (SOFC) made of a solid oxide and constructed such that a fuel electrode (anode) is formed on one side surface of a solid electrolyte shaped like a flat plate, and an air electrode (cathode) is formed on the other surface of the solid electrolyte. Both the fuel electrode and the air electrode are made of a porous material composed of conductive ceramics.

[0018] In the CS fuel cell stack, all fuel cells are stacked vertically and electrically connected in series. The CS fuel cell stack is erected on the upper surface of a base plate BP using a stacking spacer AD.

[0019] The stack intermediate piece AD ​​is a plate-shaped element with several (not shown) gas passages. As described later, fuel gas is supplied to the fuel stack CS via the stack intermediate piece AD. Gas (residual fuel gas not used to generate power and air) is also discharged from the fuel cell stack CS via the stack intermediate piece AD. The base plate BP is a circular metal plate arranged horizontally within the housing 10. The interior of the housing 10 is roughly divided into two upper and lower chambers.

[0020] The housing 10 is an enclosure that contains the fuel stack CS, the combustion chamber 20, and the reforming unit 30, and is formed almost in a circular cylinder. The housing 10 has its entire side and top surfaces covered with a thermal insulation material (not shown). The housing 10 comprises a first cylindrical body 110, a second cylindrical body 120, a third cylindrical body 130, a fourth cylindrical body 140, a fifth cylindrical body 150, and a sixth cylindrical body 160.Each of the first cylindrical body 110, the second cylindrical body 120, the third cylindrical body 130, the fourth cylindrical body 140, the fifth cylindrical body 150 and the sixth cylindrical body 160 is made of metal and has an almost cylindrical shape around each central axis, and each central axis is formed in such a way that they are coaxial with each other. Fig. Figure 1 is a schematic sectional view of a fuel cell device FC, in which a plane along the central axis is a section.

[0021] The first cylindrical body 110 is located on the innermost side of the housing 10 and accommodates the fuel cell stack CS and the stack spacer AD. An upper end of the first cylindrical body 110 is closed by a horizontal top plate 181. Furthermore, a lower end of the first cylindrical body 110 is fixed such that it rests on an upper surface of the base plate BP. The height from the lower end to the upper end of the first cylindrical body 110 is greater than the height from a lower end of the stack spacer AD to an upper end of the fuel cell stack CS. For this reason, the top plate 181 is separated from the upper end of the fuel cell stack CS. The first cylindrical body 110 has several exhaust openings 111 formed by through holes in its lower section.The multiple exhaust openings 111 are arranged at equal intervals and at the same height. The exhaust openings 111 are holes through which air (oxidation gas) is supplied to the fuel cell stack CS to generate power.

[0022] The second cylindrical body 120 is a cylindrical body arranged in such a way that it surrounds the first cylindrical body 110 from the outside. A constant clearance is formed over the entire circumference between an inner surface of the second cylindrical body 120 and an outer surface of the first cylindrical body 110. The clearance (space) formed between the second cylindrical body 120 and the first cylindrical body 110 becomes a passage (air passage 403) through which air passes to generate power while being heated.

[0023] The inner diameter of the second cylindrical body 120 is nearly equal to the outer diameter of the base plate BP. An inner surface near a lower end section of the second cylindrical body 120 rests on the entire circumference of a side surface of the base plate BP. The second cylindrical body 120 is fixed to the base plate BP at the adjacent section. This configuration prevents gas from escaping and flowing between a space below the base plate BP and the air passage 403.

[0024] The third cylindrical body 130 is arranged such that it surrounds the second cylindrical body 120 from the outside. A constant gap is formed around the entire circumference between an inner surface of the third cylindrical body 130 and an outer surface of the second cylindrical body 120. The gap formed between the third cylindrical body 130 and the second cylindrical body 120 becomes a passage (combustion exhaust passage 411) through which a high-temperature combustion exhaust gas, generated by combustion in the combustion chamber 20, passes. An upper end of the third cylindrical body 130 is positioned lower than an upper end of the second cylindrical body 120. The third cylindrical body 130 extends to a lower side than the lower end of the base plate BP.

[0025] The fourth cylindrical body 140 is arranged in such a way that it surrounds the third cylindrical body 130 from the outside. A constant clearance is formed around the entire circumference between an inner surface of the fourth cylindrical body 140 and an outer surface of the third cylindrical body 130. The clearance (space) formed between the fourth cylindrical body 140 and the third cylindrical body 130 becomes a passage (combustion exhaust gas passage 412) through which a high-temperature combustion exhaust gas, generated by combustion in the combustion chamber 20, passes.

[0026] The upper ends of the second cylindrical body 120 and the upper ends of the fourth cylindrical body 140 are aligned vertically. The upper ends of the second cylinder 120 and the upper ends of the fourth cylindrical body 140 are coupled by a top plate 182, a horizontally oriented circular plate shaped like an annulus. In other words, the upper end of the second cylinder 120 is coupled to an inner circumferential end of the top plate 182, and the upper end of the fourth cylindrical body 140 is coupled to an outer circumferential end of the top plate 182. A gap is formed between the upper end of the third cylindrical body 130 and the top plate 182. Therefore, the combustion exhaust passage 411 and the combustion exhaust passage 412 are coupled at their upper ends.

[0027] A lower end of the third cylindrical body 130 and an inner surface of the fourth cylindrical body 140 are coupled together by a lower plate 183 of a circular plate which is arranged horizontally and which is shaped like a ring. In other words, a lower end of the combustion exhaust gas passage 412 is closed by the lower plate 183.

[0028] The fourth cylindrical body 140 has an exhaust gas outlet 191, which is coupled to a lower section of it (a side slightly higher than the lower plate 183). An interior of the exhaust gas outlet 191 is connected to the combustion gas passage 412. The exhaust gas outlet 191 is a conduit that discharges the combustion gas, which passes through the combustion gas passage 412, outside the housing 10 and feeds the combustion gas to a waste heat recovery device 62, which will be described later.

[0029] The fourth cylindrical body 140 extends to a lower side than the lower end of the third cylindrical body 130. The fourth cylindrical body 140 has a horizontal flange section 141 formed at its lower end, with the horizontal flange section 141 extending outwards from the lower end of the fourth cylindrical body 140. The flange section 141 is used to secure the housing 10 when the fuel cell device FC is installed.

[0030] The fourth cylindrical body 140 has a lower plate 184 located near its lower end section, the lower plate 184 being a horizontal circular plate. The outer diameter of the lower plate 184 is approximately equal to the inner diameter of the fourth cylindrical body 140. The lower plate 184 is fixed such that an outer surface of the lower plate 184 rests on the inner surface of the fourth cylindrical body 140. A thermal insulation material TI is arranged in a space below the lower plate 184.

[0031] The fifth cylindrical body 150 is a cylindrical body located on the outermost side of the housing 10 and is arranged such that it surrounds an upper section of the fourth cylindrical body 140 from the outside. A constant clearance is formed around the entire circumference between an inner surface of the fifth cylindrical body 150 and an outer surface of the fourth cylindrical body 140. A space formed between the fifth cylindrical body 150 and the fourth cylindrical body 140 becomes a passage (air passage 401) through which air passes to generate power while being heated.

[0032] The fifth cylindrical body 150 extends to a higher side than the upper end of each of the first cylindrical body 110, the second cylindrical body 120, the third cylindrical body 130, and the fourth cylindrical body 140. An upper end of the fifth cylindrical body 150 is closed by a horizontal top plate 185. A clearance 402 is formed between the top plate 185 and the top plate 182. An upper end section of the air passage 401 and an upper end section of the air passage 403 are connected to each other via the clearance 402.

[0033] A lower end of the fifth cylindrical body 150 and an outer surface of the fourth cylindrical body 140 are coupled to each other by a lower plate 186 of a circular plate, which is arranged horizontally and is shaped like a ring. In other words, a lower end of the air passage 401 is closed by the lower plate 186.

[0034] The fifth cylindrical body 150 has an air inlet duct 192, which is coupled to a lower section of it (one side slightly higher than the lower plate 186). An interior of the air inlet duct 192 is connected to the air passage 401. The air inlet duct 192 is a conduit for introducing air into the interior of the body 10 for power generation.

[0035] The sixth cylindrical body 160 is located inside the third cylindrical body 130 and below the base plate BP. The sixth cylindrical body 160 comprises an upper cylindrical section 161 (top section) and a lower cylindrical section 162 (bottom section). The diameter of the upper cylindrical section 161 is smaller than the diameter of the lower cylindrical section 162. A lower end of the upper cylindrical section 161 and an upper end of the lower cylindrical section 162 are connected by an intermediate section 163 of a circular plate, which is horizontally oriented and shaped like an annulus. An upper end of the upper cylindrical section 161 rests on a lower surface of the base plate BP.A lower end of the lower cylindrical section 162 rests on an upper surface of the lower plate 184.

[0036] The diameter of the lower cylindrical section 162 is smaller than the diameter of the third cylindrical body 130. Therefore, a clearance is formed around the entire circumference between the third cylindrical body 130 and the sixth cylindrical body 160. Furthermore, the reforming unit 30 is arranged within this clearance, and a clearance is also formed around the entire circumference between the reforming unit 30 and the sixth cylindrical body 160. In the following description, a space formed inside the sixth cylindrical body 160 is also referred to as "an interior space 601". Furthermore, a space formed between the lower cylindrical section 162 of the sixth cylindrical body 160 and an inner cylinder 320 of the reforming unit 30 is also referred to as "an exterior space 602".

[0037] The lower cylindrical section 162 has several outlet openings 165 formed by through holes, located at a lower position than the lower end section of the reforming unit 30. These outlet openings 165 are spaced at equal intervals and at the same height. The interior 601 is connected to the exterior 602 by these outlet openings 165. The outlet openings 165 are holes through which the high-temperature combustion gas, generated by combustion in the combustion chamber 20, passes.

[0038] The combustion chamber 20 is a combustion chamber for mixing residual fuel gas (hereinafter also referred to as "residual fuel"), which is not supplied for power generation, with residual air (hereinafter also referred to as "residual air"), which is not supplied for power generation, in order to combust the residual fuel. The combustion chamber 20 is made of stainless steel. The combustion chamber 20 as a whole is formed in an almost cylindrical shape and is arranged such that it projects downwards from the center of a lower surface of the base plate BP. Viewed from a top surface, the combustion chamber 20 is further arranged at a position in the center of the housing 10 (position along a central axis of the upper cylindrical section 161).

[0039] The residual fuel and air discharged from the fuel cell stack CS are each fed to an upper end section of the burner 20 through a passage (not shown) formed in the stack intermediate section AD and a passage (not shown) formed in the base plate BP. The residual fuel and air then pass through a passage (not shown) formed in the burner 20 and reach a lower end section of the burner 20, where they are ejected downwards and mixed together. The ejected residual fuel and air are combusted in the lower end section of the burner 20, generating high-temperature combustion exhaust gas. Furthermore, the burner 20 itself is heated to a high temperature by the heat of combustion.

[0040] An ignition device IG is arranged below the combustion chamber 20. The ignition device IG is used to ignite a mixture of residual fuel and residual air expelled by the combustion chamber 20, thereby initiating the combustion of this mixture. The ignition device IG extends vertically through the lower plate 184 and the thermal insulation material TI and is positioned such that an upper end section is close to a lower end of the combustion chamber 20 to generate a spark discharge. The mixture is ignited by the ignition device IG when the fuel cell device FC is started.

[0041] The structure of Reform Unit 30 is described with reference to Fig. 1 and Fig. 2 described. The reforming unit 30 is an integrated unit comprising a reformer 302, which produces a fuel gas (reformed fuel: gas containing hydrogen) from town gas through a reforming reaction, and an evaporator 301, which generates steam and supplies the steam to the reformer 302. The reforming unit 30 as a whole is designed in an almost cylindrical shape (see Fig. 2) and is arranged in a space between the third cylindrical body 130 and the sixth cylindrical body 160 in the housing 10. The reforming unit 30 comprises an outer cylinder 310, an inner cylinder 320, a top plate 330, a first lower plate 340, a second lower plate 350, a first separating plate 360, and a second separating plate 370. Between these parts, the outer cylinder 310, the inner cylinder 320, the top plate 330, the first lower plate 340, the second lower plate 350, and a section that is deeper than the first lower plate 340 of the first separating plate 360 ​​form an outer shape of the reforming unit 30.

[0042] The outer cylinder 310 is a cylindrical body forming an outer surface of the reforming unit 30. A central axis of the outer cylinder 310 coincides with a central axis of the third cylindrical body 130. An outer diameter of the outer cylinder 310 is nearly equal to an inner diameter of the third cylindrical body 130. Almost the entire outer surface of the outer cylinder 130 rests on an inner surface of the third cylindrical body 130. The outer cylinder 310 extends to a lower side than the lower plate 183.

[0043] The inner cylinder 320 is a cylindrical body that forms an inner surface for the reforming unit 30. The central axis of the inner cylinder 320 coincides with the central axis of the third cylindrical body 130. The outer diameter of the inner cylinder 320 is smaller than the inner diameter of the outer cylinder 310. Therefore, a space is formed between the outer cylinder 310 and the inner cylinder 320. As will be described later, part of this space is where water is converted to steam and flows. Another part of the space is where the reforming reaction takes place to produce the fuel gas.

[0044] The inner diameter of the inner cylinder 320 is larger than the outer diameter of the lower cylindrical section 162 of the third cylindrical body 130. For this reason, as described above, a clearance is formed around the entire circumference between the reforming unit 30 and the sixth cylindrical body 160. The upper end of the inner cylinder 320 has the same height as the upper end of the outer cylinder 310. Conversely, the lower end of the inner cylinder 320 is higher than the lower end of the outer cylinder 310 and has the same height as the lower end of the lower plate 183.

[0045] The top plate 330 is a circular plate, arranged horizontally and shaped like an annulus. An outer surface of the top plate 330 is coupled to an upper end section of the inner surface of the outer cylinder 310. Furthermore, an inner surface of the top plate 330 is coupled to an upper end section of the outer surface of the inner cylinder 320. In this way, the upper end of the outer cylinder 310 and the upper end of the inner cylinder 320 are coupled to each other by the top plate 330.

[0046] The first lower plate 340 is a circular plate arranged horizontally and formed in the shape of an annulus. The first lower plate 340 is positioned such that its height is equal to the height of the lower plate 183. An outer surface of the first lower plate 340 is coupled to an inner surface of the first separating plate 360, which will be described later. Furthermore, an inner surface of the first lower plate 340 is coupled to a lower end section of the inner surface of the inner cylinder 320.

[0047] The second lower plate 350 is a circular plate arranged horizontally and formed in the shape of a ring. An outer surface of the second lower plate 350 is coupled to a lower end section of the inner surface of the outer cylinder 310. Furthermore, an inner surface of the second lower plate 350 is coupled to a lower end section of the outer surface of the first separating plate 360, which will be described later. For this reason, the second lower plate 350 is positioned lower than the first lower plate 340.

[0048] The first separating plate 360 ​​is a cylindrical body, part of which is arranged in the reforming unit 30. A central axis of the first separating plate 360 ​​coincides with a central axis of the outer cylinder 310 and a central axis of the inner cylinder 320. The outer diameter of the first separating plate 360 ​​is smaller than the inner diameter of the outer cylinder 310. For this reason, a constant clearance is formed around the entire circumference between the outer cylinder 310 and the first separating plate 360.

[0049] The upper end of the first partition plate 360 ​​is lower than the upper end of the outer cylinder 310. Therefore, a gap is formed between the upper end of the first partition plate 360 ​​and a lower surface of the uppermost plate 330. The lower end of the first partition plate 360 ​​is the same height as the lower end of the outer cylinder 310. As described above, the first partition plate 360 ​​couples the second lower plate 350 externally with its lower end. Furthermore, the first partition plate 360 ​​couples the first lower plate 340 internally.

[0050] The second separating plate 370 is a cylindrical body located entirely within the reforming unit 30. A central axis of the second separating plate 370 coincides with a central axis of the outer cylinder 310 and a central axis of the inner cylinder 320. The outer diameter of the second separating plate 370 is smaller than the inner diameter of the first separating plate 360. Therefore, a constant clearance is maintained around the entire circumference between the second separating plate 370 and the first separating plate 360. Furthermore, the inner diameter of the second separating plate 370 is larger than the outer diameter of the inner cylinder 320. Therefore, a constant clearance is also maintained around the entire circumference between the second separating plate 370 and the inner cylinder 320.

[0051] The second separating plate 370 is fixed to the uppermost plate 330 in such a way that an upper end of the second separating plate 370 is brought into contact with a lower surface of the uppermost plate 330. A lower end of the separating plate 370 is higher than a lower end of the inner cylinder 320. For this reason, a gap is formed between the lower end of the second separating plate 370 and an upper surface of the first lower plate 340.

[0052] According to the structure described above, the reforming unit 30 comprises: a first chamber 381, which is a chamber formed between the outer cylinder 310 and the first separating plate 360; a second chamber 382, ​​which is a chamber formed between the first separating plate 360 ​​and the second separating plate 370; and a third chamber 383, which is a chamber formed between the second separating plate 370 and the inner cylinder 320. The first chamber 381 and the second chamber 382 are coupled to each other above the first separating plate 360, while the second chamber 382 and the third chamber 383 are coupled to each other below the second separating plate 370.

[0053] One end of a water supply line 391 is connected from below to the second lower plate 350. The water supply line 391 is a line for supplying water to the first room 381. The other end of the water supply line 391 is connected to a water supply pump (not shown) located outside the housing 10.

[0054] As will be described in detail later, the water supplied from the water supply line 391 into the first chamber 381 is heated by the high-temperature combustion gas passing through the combustion exhaust passage 412, thus converting it into steam. The steam then passes sequentially through the first chamber 381 and the second chamber 382, ​​reaching an inlet of the third chamber 383. In this way, sections of the reforming unit 30, the first chamber 381, the second chamber 382, ​​and a wall surface dividing the first chamber 381 and the second chamber 382 are supplied with water from the outside to generate the steam; that is, sections corresponding to the evaporator 301.

[0055] The first chamber 381 contains a support plate 352. The support plate 352 is a plate arranged horizontally in such a way that it divides the first chamber 381 vertically in an annular shape. The support plate 352 is fixed to the outer cylinder 310 and the first partition plate 360 ​​in a position where the support plate 352 is at the same height as the first lower plate 340. The support plate 352 has several (not shown) through-holes through which water can pass. A section of the first chamber 381 higher than the support plate 352 is filled with heat transfer accelerators CB to accelerate the heat transfer from the outer cylinder 310 to the water. The heat transfer accelerators CB are several spheres (ceramic spheres) made of aluminum oxide.

[0056] One end of a town gas supply line 392 is connected from below to the first lower plate 340. The town gas supply line 392 is a line for supplying an inlet section of the third room 383 with town gas. The other end of the town gas supply line 392 is connected to a desulfurization device 61 (see Fig. 3).

[0057] The third chamber 383 is filled with a reforming catalyst RC. The reforming catalyst RC is an element produced by holding a catalyst metal, such as nickel, on the surface of a spherical body made of aluminum oxide. In the third chamber 383, a (not shown) horizontally arranged metal mesh is fixed at a position slightly higher than the lower end of the second partition plate 370, and the reforming catalyst RC is held from below by the metal mesh.

[0058] As described in detail later, the town gas, supplied from the town gas supply line 392 to the interior of the reforming unit 30, is mixed with the steam at the inlet section of the third chamber 383 and then flows upwards in the third chamber 383. At this time, the town gas and the steam are brought into contact with the reforming catalyst RC to effect a steam reforming reaction, thereby producing the fuel gas (gas containing hydrogen). In this way, the reforming unit 30, the third chamber 383, and a wall surface for dividing the third chamber 383 are sections supplied with steam from the evaporator 31 and with town gas from the outside to effect the steam reforming reaction; in other words, sections corresponding to the reformer 302.The reforming catalyst RC is filled into the entire circumference of the third chamber 383. Therefore, the water supplied by the evaporator 301 never passes through the third chamber 383 without coming into contact with the reforming catalyst RC.

[0059] One end of the fuel gas supply line 393 is coupled to a section near an upper end section of the inner cylinder 320. The fuel gas supply line 393 is a line for supplying the fuel gas generated in the reforming unit 30 (reformer 302) to the fuel cell stack CS. The other end of the fuel gas supply line 393 is coupled to a lower surface of the base plate BP. The fuel gas passes through the fuel gas supply line 393 from an upper section 383 and reaches the base plate BP. The fuel gas then passes through a passage (not shown) formed in the base plate BP and a passage (not shown) formed in the stack intermediate section AD and is supplied to the fuel cell stack CS.

[0060] The fuel gas supply line 393 comprises, from an upstream side, a horizontal section 393a, a curved section 393b and a vertical section 393c (see Fig. 2) The horizontal section 393a is a conduit extending horizontally from the inner cylinder 320 to the central axis of the inner cylinder 320. The curved section 393b is a conduit extending from a downstream end section of the horizontal section 393a in the form of an arc around the central axis of the inner cylinder 320. The vertical section 393c is a conduit extending vertically upwards from a downstream end section of the curved section 393b.

[0061] The fuel gas supply line 393 is designed in this shape and is therefore slightly curved as a whole. Consequently, even if the fuel gas supply line 393 is heated to a high temperature and expands thermally while the fuel cell device FC is operating, no thermal stress is induced in the fuel gas supply line 393. As a result, the reforming unit 30, the base plate BP, and the fuel gas supply line 393 itself are prevented from breaking due to thermal stress.

[0062] The reforming unit 30 is held from below by a cylindrical sealing block SB, which is made of a heat-resistant material and is in the shape of a cylinder. An upper end of the sealing block SB rests on a lower surface (first lower plate 340) of the reforming unit 30, and a lower end of the sealing block SB rests on an upper surface of the lower plate 184. The inner diameter of the sealing block SB is equal to the inner diameter of the reforming unit 30. Furthermore, a dimension (thickness) in a radial direction of the sealing block SB is smaller than a dimension (thickness) in a radial direction of the reforming unit 30. For this reason, as described in Fig. Figure 1 shows a space formed outside the sealing block SB (on the underside of the reforming unit 30).

[0063] A space outside the sixth cylindrical body 160 and space SP are separated from each other by the reforming unit 30 and the sealing block SB, so that the gas cannot pass between these spaces. Since the high-temperature combustion exhaust gas does not flow into space SP, the temperature in space SP is kept at a comparatively low level.

[0064] Subsequently, the flows of the gases (air, town gas, fuel gas, and combustion exhaust) while the fuel cell device (FC) is operating are mainly described with reference to Fig. 1, Fig. 2 to Fig. 3 described.

[0065] First, the flow of air (oxidation gas) supplied to the fuel cell stack CS to generate power is described. The air is supplied by a blower (not shown) located outside the housing 10 through the air inlet line 192 into the interior of the housing 10.

[0066] The air supplied through the air inlet line 192 flows upwards in the air passage 401. The air then flows over the clearance 402 into the air passage 403 and flows downwards in the air passage 403.

[0067] The combustion exhaust gas passages 411 and 412 are located between the air passages 401 and 403. The high-temperature combustion exhaust gas passes through these passages. As a result, the air introduced into the housing 10 is heated by the combustion exhaust gas as it passes through air passages 401 and 403, thus increasing its temperature. In other words, heat is exchanged between the air and the combustion exhaust gas.

[0068] While the fuel cell stack CS continues to generate power, it is heated to a high temperature, and consequently, the first cylindrical body 110 is also heated to a high temperature by radiant heat from the fuel cell stack CS. As the air passes through the air passage 403, it comes into contact with the first cylindrical body 110 and is therefore heated further.

[0069] In this way, air passage 401 and air passage 403 become passages through which air flows while being heated by the heat of the combustion exhaust gas and by the radiant heat from the fuel cell stack CS. For this reason, in the following description, air passage 401 and air passage 403 are collectively referred to as "air heating passage 40". The air heating passage 40 is arranged in such a way that it surrounds the fuel stack CS from the side. The air heating passage 40 can be considered a component corresponding to a "preheater" that exchanges combustion exhaust gas heat (heat of the combustion gas) generated by combustion in the combustion chamber 20 between the combustion gas and the air supplied to the fuel cell stack CS.

[0070] The air reaching a lower section of the air passage 403 is expelled from the exhaust openings 111, which are formed in the first cylindrical body 110, towards the fuel cell stack CS. The air then reaches the air electrode of each fuel cell, thus being supplied to generate power.

[0071] The flow of the fuel gas supplied to the fuel cell stack CS and the flow of the town gas from the raw fuel gas source are described. The town gas is supplied from outside the housing 10 to the interior of the reforming unit 30 via the town gas supply line 392. The desulfurization device 61 is arranged between a town gas supply source and the town gas supply line 392. The desulfurization device 61 is a device for removing a sulfur component contained in the town gas. The town gas passes through the desulfurization device 61, removing the sulfur component, which has a detrimental effect on the fuel cell's performance, and is then supplied to the interior of the reforming unit 30.

[0072] The town gas, supplied from the town gas supply line 392 to the interior of the reforming unit 30, is mixed with the steam at the inlet section of the third chamber 383. The town gas then flows upwards in the third chamber 383, which is filled with the reforming catalyst RC.

[0073] The high-temperature combustion exhaust gas passes through a space formed between the lower cylindrical section 162 of the sixth cylindrical body 160 and the inner cylinder 320 of the reforming unit 30. As the town gas and water vapor pass through the third space 383, they are heated by the combustion exhaust gas, thus increasing their temperature. In other words, the town gas and water vapor exchange heat with the combustion exhaust gas. Furthermore, the reforming catalyst RC, which is filled into the third space 383, is also brought to a high temperature by heat transfer through the inner cylinder 320.

[0074] The sixth cylindrical body 160, which surrounds the combustion chamber 20, is heated not only by the combustion exhaust gas but also by the radiant heat from the combustion chamber 20, thus bringing it to an extremely high temperature. As a result, the radiant heat from the sixth cylindrical body 160 (also referred to as the radiant heat arriving from the combustion chamber 20 via the sixth cylindrical body 160), which is brought to this high temperature, reaches the inner cylinder 320 of the reforming unit 30. In other words, the reformer 302, which includes the inner cylinder 320, is heated not only by the combustion exhaust gas but also by the radiant heat from the combustion chamber 20.

[0075] When a mixed gas consisting of town gas and steam is brought into contact with the reforming catalyst RC in this state, the steam reforming reaction occurs in the third chamber 383 (reformer 302). As a result, the fuel gas is produced from the mixed gas. In this respect, the steam reforming reaction is an endothermic reaction; therefore, heat must be supplied to maintain its stability. In the present embodiment, both the heat from the combustion exhaust gas applied through the inner cylinder 320 and the radiant heat from the combustion chamber 20 are used to maintain the steam reforming reaction.

[0076] The fuel gas generated in the reformer 302 passes through the fuel gas supply line 393 and a passage in the stack intermediate piece AD, and is then fed to the fuel cell stack CS. The fuel gas reaches the fuel electrode of each fuel cell, thus supplying it to generate power.

[0077] The flow of the fuel exhaust gas is described. As described above, the residual fuel and residual air discharged from the fuel stack CS are fed to the combustion chamber 20, and the residual fuel is combusted in the lower end of the combustion chamber 20. As a result of the combustion, the high-temperature combustion gas is generated in the sixth cylindrical body 160 (inner chamber 601). The combustion exhaust gas passes through the outlet opening 165 and flows outwards from the sixth cylindrical body 160 to the outside (outer chamber 602).

[0078] The combustion exhaust gas then flows upwards along the inner cylinder 320 in the outer chamber 602. At this time, the heat from the combustion exhaust gas, as described above, is transferred through the inner cylinder 320 to the third chamber 383 and is used as part of the heat to sustain the steam reforming reaction.

[0079] The combustion exhaust gas, passing through the outer chamber 602, flows upwards in the combustion exhaust gas passage 411, exchanging heat with the air flowing in the air passage 403. Subsequently, the combustion exhaust gas flows downwards in the combustion exhaust gas passage 412, exchanging heat with the air flowing in the air passage 401.

[0080] The outer cylinder 310 of the reforming unit 30 rests on an inner surface of the third cylindrical body 130 at a section above the support plate 352. For this reason, the outer cylinder 310 is heated to a high temperature by the combustion exhaust gas passing through the combustion exhaust gas passage 412.

[0081] The water supplied from water supply line 391 to the interior of the first chamber 381 is heated by the heat transferred from the outer cylinder 310 (heat from the combustion exhaust gas), thus bringing it into contact with the steam. In other words, the water exchanges heat with the combustion exhaust gas, thereby generating steam in the first chamber 381.

[0082] The combustion exhaust gas, reaching a lower end section of the combustion exhaust gas passage 412, passes through the exhaust gas line 191 and is fed to the exhaust gas recovery unit 62. The exhaust gas recovery unit 62 is a unit that allows the combustion exhaust gas to exchange heat with water in order to produce hot water. In this way, the fuel cell device FC can generate not only power but also hot water, thus becoming a combined heat and power (CHP) system for utilizing energy with high efficiency.

[0083] The flow of water and steam is then described. The reforming unit 30 (evaporator 301) is supplied with water by the (not shown) water supply pump, which is located outside the housing 10, via the water supply line 391. The water supply line 391 is connected from below to the second lower plate 350. Therefore, the water supplied to the reforming unit 30 initially remains in a space formed in a lower section of the first space 381. Specifically, the water is stored in a water storage section WS of a space that is lower than the support plate 352 of the first space 381.

[0084] The water storage section WS is a space subdivided by a section that is deeper than the lower plate 183 of the outer cylinder 310 (hereinafter referred to as "a partition 311"), the second lower plate 350 and a section that is deeper than the first lower plate 340 of the first partition plate 360 ​​(hereinafter referred to as "a partition 361").

[0085] As in Fig. As shown in Figure 2, the partition 311, the second lower plate 350, and the partition 361, which divide the water storage section WS, are formed in a shape created by extending a portion of a lower surface of the reforming unit 30 downwards. These sections are arranged in the space SP (see Figure 2). Fig. 1) In other words, these sections are arranged in a space that the high-temperature gas does not reach and which is consequently brought to a comparatively low temperature.

[0086] Furthermore, the outer cylinder 310 is heated by the combustion exhaust gas passing through the combustion exhaust gas passage 412, but is not directly heated by the combustion exhaust gas, since the partition wall 311 is located at a lower position than the lower plate 183. For this reason, the water in the water storage section WS is not boiled, but rather the entire interior of the water storage section WS is filled with water (liquid).

[0087] Since the reforming unit 30 (the evaporator 301) is supplied with water by the water supply pump, the water level in the first chamber 381 is maintained at a position slightly higher than the top surface of the support plate 352. For this reason, the heat transfer accelerator elements CP (spheres made of aluminum oxide) that are embedded in the top surface of the support plate 352 of the first chamber 381 are partially submerged in the water.

[0088] In the first chamber 381, the heat transfer accelerator components CB are also brought to a high temperature by heat transfer from the outer cylinder 310, which is heated to a high temperature by the combustion exhaust gas. The water on the side higher than the support plate 352 of the first chamber 381 is brought into contact with the heat transfer accelerator components CB, causing it to boil and be converted into water vapor.

[0089] In this way, the water in the first chamber 381 is converted into steam, and the steam flows upwards. Then, in the second chamber 382, ​​the steam flows downwards and is fed to the third chamber 383 (reformer 302).

[0090] Radiation in the fuel cell device FC (in the housing 10) is referred to Fig. 4 described. As described above, the fuel cell stack CS is brought to a high temperature while the fuel cell stack CS is in operation, so that the radiant heat from the fuel cell stack CS is emitted to its surroundings. Fig. Figure 4 shows the radiant heat emitted by the CS fuel cell stack to the environment, indicated by arrows represented by reference symbols RD1. Hereinafter, the radiant heat emitted by the CS fuel cell stack will also be referred to as "radiant heat RD1".

[0091] Almost the entire air heating passage 40, which is formed from air passage 401 and air passage 403, is arranged in such a way that it surrounds the fuel cell stack CS. Furthermore, there is no blocking element to obstruct the radiant heat RD1 from the fuel cell stack CS between the fuel cell stack CS and the air heating passage 40. The radiant heat RD1 reaches the air heating passage 40 directly, thus enabling the air heating passage 40 to be heated effectively.

[0092] The temperature of the air flowing through the air heating passage 40 is lower than the temperature of the fuel cell stack CS. As a result, the temperature of the first cylindrical body 110 is lower than the temperature of the fuel cell stack CS. Therefore, the fuel cell stack CS is surrounded by the low-temperature air heating passage 40 (preheating), and can thus be said to be cooled by heat radiation. This configuration reduces the need for an excessive supply of air for cooling the fuel cell stack CS in order to generate power. In the present embodiment, the rotational speed of a blower for supplying air can be reduced compared to a case where the air heating passage 40 is not arranged around the fuel cell stack CS, which can consequently improve the overall efficiency of the fuel cell device FC.

[0093] In this way, the fuel cell device FC according to the present embodiment has a compact structure in which the reformer 302 and the combustion chamber 20 are arranged in a single housing, and can prevent the combustion chamber 20 from being damaged by the radiant heat from the fuel cell stack CS.

[0094] In this respect, to cool the fuel cell stack CS solely by thermal radiation, consideration can also be given to using a configuration in which the entire circumference of the fuel cell stack CS is surrounded by a reformer (not by the air heating passage 40). However, in such a configuration, it is necessary to surround the entire large area from one end to the top of the fuel cell stack CS (the passage filled with the reforming catalyst), so the reformer's flow resistance is likely to be excessively high. As a result, the load on the fuel supply pump will be excessively high, and consequently, the overall energy utilization efficiency of the fuel cell device FC is likely to be reduced.

[0095] In contrast, in a setup where the entire perimeter of the fuel cell stack CS is surrounded by the air heating passage 40, as in the case of the present embodiment, even in the setup where the entire large area from the lower end to the upper end of the fuel cell stack CS is surrounded by the air heating passage 40, the through-resistance of the air heating passage 40 is not made excessively large.

[0096] The interior of the housing 10 is generally divided into two upper and lower chambers by the base plate BP, which is a plate extending along a horizontal plane. The fuel cell stack CS is located in the upper chamber above the base plate BP, while both the combustion unit 20 and the reforming unit 30 are located in the lower chamber below the base plate BP. As a result, the radiant heat from the fuel cell stack CS is blocked by the base plate BP and does not directly reach the combustion unit 20 or the reforming unit 30. In other words, the reforming unit 30 (reformer 302) and the combustion unit 20 are positioned such that the radiant heat RD1 from the fuel cell stack CS does not directly reach the interior of the housing 10.For this reason, the combustion chamber 20 is not directly heated by the radiant heat RD1, which consequently prevents the temperature of the combustion chamber 20 from being excessively increased and consequently from being damaged or breaking.

[0097] Furthermore, the reforming unit 30 is not directly heated by the radiant heat RD1, which consequently prevents the temperature of the reforming unit 30 from increasing excessively. As a result, it is possible to prevent a reduction in heat transfer from the combustion chamber 20 to the reforming unit 30, thus preventing the temperature of the combustion chamber 20 from rising. The base plate BP corresponds to a "blocking plate" as described in this disclosure.

[0098] While the CS fuel cell stack is operating, the combustion engine 20 is heated to a higher temperature than the CS fuel cell stack. For this reason, radiant heat is also emitted from the combustion engine 20 into the surroundings. Fig. Figure 4 shows the radiant heat emitted by the combustion engine 20 to the environment, represented by the reference symbol RD2. In the following, the radiant heat emitted by the combustion engine 20 will also be referred to as "radiant heat RD2".

[0099] As described above, the reforming unit 30, including the reformer 302, is arranged such that the combustion chamber 20 is surrounded from the side. As a result, the reformer 302 is heated by the radiant heat RD2, and consequently the steam reforming reaction (endothermic reaction) is stably effected in the reformer 302.

[0100] The temperature of the reforming unit 30 is lower than the temperature of the combustion chamber 20. Therefore, the combustion chamber 20 is surrounded by the reforming unit 30 at a low temperature, and consequently, it can also be said that the combustion chamber 20 is cooled by thermal radiation. This arrangement prevents the combustion chamber 20 from overheating and becoming damaged.

[0101] Furthermore, the radiant heat RD2 from the combustion engine 20 is blocked by the base plate BP and consequently does not directly reach the fuel cell stack CS. This can therefore further reduce the possibility of the fuel cell stack CS being heated to an excessively high temperature.

[0102] In the present embodiment, only the air heating passage 40 is arranged on the side (circumference) of the fuel cell stack CS, while the combustion chamber 20 and the reformer 302 are not arranged. As a result, it is not necessary to form a complex passage to surround the fuel cell stack CS from the side, and consequently the interior of the housing 10 can have a comparatively simple structure.

[0103] Up to this point, the embodiment of the present disclosure has been described. However, the present disclosure is not limited to this specific embodiment. That is to say, an example in which a person skilled in the art adds a suitable modification to the present embodiment is, insofar as the example has the features of the present disclosure, included within the scope of protection of the present disclosure. For example, the respective elements contained by the respective specific embodiments and the arrangement, material, condition, shape, and size of each of the elements are not limited to those shown and can be suitably modified.Furthermore, the respective elements contained in the respective embodiments can be combined with one another, provided that they can be technically combined, and a combination of the elements is included in the scope of protection of the present disclosure, provided that the combination comprises the features of the present disclosure.

Claims

[1] Fuel cell device comprising the following: a reformer (302) that reforms a crude fuel to produce a reformed fuel; a fuel cell stack (CS) that is supplied with the reformed fuel and an oxidant and generates power; a combustion engine (20) that burns the reformed fuel discharged from the fuel cell stack (CS) in order to heat the reformer (302); and a housing (10) in which the fuel cell stack (CS), the reformer (302) and the combustion unit (20) are accommodated; and a blocking plate (BP) that blocks the air supplied to the fuel cell stack (CS) to generate power and the combustion exhaust gas generated in the combustion chamber (20) in such a way that the air and the combustion exhaust gas do not flow out and into each other, wherein the reformer (302) and the combustion chamber (20) are arranged in a position that does not directly receive radiant heat from the fuel cell stack (CS), wherein the housing (10) has arranged the blocking plate (BP) along a horizontal plane in the housing (10), wherein the fuel cell stack (CS) is arranged above the blocking plate (BP) and wherein the reformer (302) and the combustion chamber (20) are arranged below the blocking plate (BP), characterized by , that the combustion engine (20) is arranged in a central position of the housing (10) when viewed from above and the reformer (302) is arranged in such a way that it surrounds the combustion chamber (20) from the side. [2] Fuel cell device comprising the following: a reformer (302) that reforms a crude fuel to produce a reformed fuel; a fuel cell stack (CS) that is supplied with the reformed fuel and an oxidant and generates power; a combustion engine (20) that burns the reformed fuel discharged from the fuel cell stack (CS) in order to heat the reformer (302); and a housing (10) in which the fuel cell stack (CS), the reformer (302) and the combustion engine (20) are accommodated; a first enclosure (110) arranged on an innermost side of the housing (10) in which the fuel cell stack (CS) is accommodated; and a second enclosure (120) arranged in such a way that it surrounds the first enclosure (110) from the outside; and a blocking plate (BP) that blocks the air supplied to the fuel cell stack (CS) to generate power and the combustion exhaust gas generated in the combustion chamber (20) in such a way that the air and the combustion exhaust gas do not flow out and into each other, wherein the reformer (302) and the combustion chamber (20) are arranged in a position that does not directly receive radiant heat from the fuel cell stack (CS), and wherein a space is formed between the second enclosure (120) and the first enclosure (110), which is to become a passage (403) through which the air supplied to the fuel cell stack to generate power passes while being heated, characterized by , that an inner surface near a lower end section of the second enclosure (120) is caused to lie against an entire circumference of a side surface of the blocking plate (BP). [3] Fuel cell device according to claim 1 or 2, further comprising: a preheater (40) which exchanges combustion exhaust heat generated by combustion in the combustion chamber (20) between the combustion exhaust gas from the combustion chamber (20) and the oxidizer supplied to the fuel cell stack (CS), wherein the preheating (40) is arranged in such a way that it surrounds the fuel cell stack (CS) from the side.

Images