JP2017016940A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To approximately evenly raise temperatures of a plurality of fuel cells.SOLUTION: A fuel cell system 1 includes: a housing 21 whose inner surface 211 is formed from thermal insulation material; and a lining part 27 that is formed from thermal conduction material whose thermal conductivity is higher than that of the thermal insulation material. The lining part 27, while being apart from the housing 21's inner surface 211, covers the inner surface 211 and houses a plurality of fuel cells 23 in an inner space 272. At the time of start operation of the fuel cell system 1, a heating gas, a fluid for heating, is supplied to a gap space 212 between the housing 21 and the lining part 27; radiation from the lining part 27 heats the plurality of fuel cells 23. Thereby, temperature rise rate differences caused by positions of the plurality of fuel cells 23 in the inner space 272 are suppressed, making it possible to approximately evenly raise temperatures of the plurality of fuel cells 23.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system.

  Conventionally, various fuel cell systems that generate power using fuel cells have been proposed. For example, in the fuel cell module of Patent Document 1, a heat insulating material is provided so as to surround a cell stack that generates power using reformed gas, and the cell stack and the heat insulating material are accommodated in a casing. In the fuel cell module, by flowing air through the space between the housing and the heat insulating material, the leaked gas leaking into the space is exhausted out of the housing together with the air.

  In the fuel cell device of Patent Document 2, the outer case of the fuel cell module storage chamber in which a plurality of fuel cells are stored has a double wall structure including an inner wall and an outer wall. In the fuel cell device, the oxygen-containing gas is warmed by circulating the oxygen-containing gas between the inner wall and the outer wall. The warmed oxygen-containing gas is supplied to the fuel cell module, so that the power generation efficiency of the fuel cell module is improved.

  On the other hand, in the solid oxide fuel cell module of Patent Document 3, the reformer is opposed to one main surface of the plate stack and the steam generator is opposed to the other main surface in the heat insulating casing. Then, during the start-up operation of the solid oxide fuel cell module, the heating gas is sent out along the both main surfaces of the plate stack from the heating device disposed on the side of the plate stack. Thereby, compared with the case where a plate-shaped stack is heated from the single side | surface, the difference of the temperature distribution of a plate-shaped stack becomes small.

  In the fuel cell of Patent Document 4, a radiant is provided between a steam reformer that steam reforms a fuel gas and a battery stack that generates power by an electrochemical reaction between an oxidizing gas and a reformed fuel gas. A tube is placed. During the start-up operation of the fuel cell, the cell stack and the steam reformer are preheated by radiant heat from the radiant tube. When the battery stack reaches a temperature at which efficient power generation can be performed, heating of the battery stack and the steam reformer by the radiant tube is stopped, and the fuel cell shifts to a steady operation.

International Publication No. 2012/128368 JP 2008-192347 A JP 2011-233476 A JP2013-134929A

  By the way, in the fuel cell system in which a plurality of fuel cells are arranged in the housing as in Patent Document 2, the state of temperature rise differs depending on the position of each fuel cell in the housing during the start-up operation of the fuel cell system. . For example, in the heating structure as in Patent Document 3, the temperature of the fuel cell close to the heating device is raised first, and the temperature of the fuel cell far from the heating device is raised with a delay. If it is a heating structure like patent document 4, the fuel cell close | similar to a radiant tube will heat up first, and the fuel cell which left | separated from the radiant tube will be heated up late. On the other hand, if the heating device of Patent Document 3 and the radiant tube of Patent Document 4 are provided near each of the plurality of fuel cells, the fuel cell system may be increased in size.

  The present invention has been made in view of the above problems, and an object thereof is to raise the temperature of a plurality of fuel cells substantially evenly.

  The invention according to claim 1 is a fuel cell system, which is a reformer that reforms raw fuel to generate fuel gas, and solid oxidation that generates electricity using the fuel gas and oxidant gas, respectively. A plurality of solid fuel cells, a housing having an inner surface or an outer surface formed of a heat insulating material, a heat conductive material having higher heat conductivity than the heat insulating material, and spaced apart from the inner surface of the housing An inner space that covers the inner surface and accommodates the plurality of fuel cells in an inner space, and a heating fluid is supplied to a gap space between the housing and the inner liner during start-up operation. The plurality of fuel cells are heated by radiation from the tension portion.

  Invention of Claim 2 is a fuel cell system of Claim 1, Comprising: The said lining part covers the said inner surface while separating from the said inner surface of the said housing, The said outer wall part, and heat | fever And a partition wall section that is connected in a conductive manner and divides the internal space into a plurality of cell arrangement areas in which the plurality of fuel cells are distributed.

  A third aspect of the present invention is the fuel cell system according to the second aspect, wherein a plurality of cylindrical portions that respectively surround the plurality of cell arrangement areas are formed by the partition walls.

  A fourth aspect of the present invention is the fuel cell system according to the third aspect, wherein the partition wall portion includes the plurality of cylindrical portions and separates the plurality of cell arrangement areas from each other. Battery chambers are formed.

  A fifth aspect of the present invention is the fuel cell system according to any one of the second to fourth aspects, wherein the number of fuel cells disposed in each of the plurality of cell disposition areas is one.

  A sixth aspect of the present invention is the fuel cell system according to any one of the first to fifth aspects, wherein the lining portion supports the plurality of fuel cells via a heat insulating member.

  A seventh aspect of the present invention is the fuel cell system according to any one of the first to sixth aspects, further comprising a decompression unit that makes the gap space a decompressed atmosphere during steady operation.

  The invention according to claim 8 is the fuel cell system according to claim 7, wherein, based on the temperature of the internal space of the lining portion, the pressure reducing portion is controlled to adjust the pressure of the gap space. And a pressure control unit.

  A ninth aspect of the present invention is the fuel cell system according to any one of the first to sixth aspects, further comprising a working fluid supply unit that supplies a working fluid to the gap space during steady operation. Heating of water supplied to the reformer, preheating of the raw fuel supplied to the reformer, or the plurality of fuel cells using the working fluid heated through the space The oxidant gas supplied to is preheated.

  A tenth aspect of the present invention is the fuel cell system according to any one of the first to sixth aspects, wherein the oxidant gas is supplied to the plurality of fuel cells via the gap spaces during steady operation. Is done.

  In the present invention, the temperature of the plurality of fuel cells can be raised substantially evenly.

It is a figure which shows the structure of the fuel cell system which concerns on 1st Embodiment. It is a figure which shows a part of fuel cell system. It is a figure which shows the structure of the fuel cell system which concerns on 2nd Embodiment. It is a figure which shows the structure of the fuel cell system which concerns on 3rd Embodiment.

  FIG. 1 is a diagram showing a configuration of a fuel cell system 1 according to a first embodiment of the present invention. The fuel cell system 1 is a power generation system that generates power using a fuel cell. The fuel cell system 1 includes a hot module 2, an impurity removal unit 41, a first heat exchanger 42, a blower 43, a second heat exchanger 44, a condensing unit 45, a water vapor generating unit 46, and exhaust gas combustion. Unit 47, raw fuel supply source 48, water supply unit 31, heating fluid generation unit 33, decompression unit 51, and pressure control unit 52.

  The hot module 2 includes a housing 21, a reformer 22, a plurality of fuel cells 23, a lining portion 27, and a heat insulating member 29. The housing 21 is a substantially rectangular parallelepiped housing, for example. The inner surface 211 of the housing 21 is formed of a heat insulating material (for example, rock wool) having a relatively high heat insulating property. As the housing 21, for example, a metal container whose entire inner surface is covered with a heat insulating material is used. The outer surface of the housing 21 may be formed of the above-described heat insulating material. When the outer surface of the housing 21 is formed of a cut-off material, the inner surface 211 of the housing 21 is formed over the entire surface by a relatively thin metal plate, for example. In the following description, the inner surface 211 of the housing 21 is described as being formed of a heat insulating member. Inside the housing 21, a reformer 22, a plurality of fuel cells 23, a lining portion 27 and a heat insulating member 29 are accommodated. In the example shown in FIG. 1, twelve fuel cells 23 are accommodated in the housing 21. The plurality of fuel cells 23 have the same structure. In FIG. 1, a part of the configuration of the fuel cell system 1 (for example, the housing 21 and the lining portion 27) is shown in cross section.

  The lining portion 27 includes an outer wall portion 271 and a partition wall portion 28. The outer wall part 271 is a substantially rectangular parallelepiped housing, for example. The outer wall portion 271 of the lining portion 27 covers the inner surface 211 while being separated from the inner surface 211 of the housing 21. In the example shown in FIG. 1, the lining portion 27 covers substantially the entire inner surface 211 while being separated from the inner surface 211 of the housing 21. In the following description, the space between the lining portion 27 and the housing 21, that is, the space between the outer wall portion 271 of the lining portion 27 and the inner surface 211 of the housing 21 is referred to as “gap space 212”. The housing 21 is provided with a supply port 213 and a discharge port 214. In the fuel cell system 1, fluid is supplied to the gap space 212 from the outside of the housing 21 through the supply port 213. Further, the fluid in the gap space 212 is discharged to the outside of the housing 21 through the discharge port 214. A decompression unit 51 is provided on the heating fluid discharge pipe 258 connected to the discharge port 214. A pressure control unit 52 is connected to the decompression unit 51.

  The outer wall portion 271 is formed of a heat conductive material having higher heat conductivity than the above-described heat insulating material forming the inner surface 211 of the housing 21. The outer wall portion 271 is formed of, for example, a relatively thin metal plate. The outer wall portion 271 is supported inside the housing 21 by a plurality of heat insulating support members (not shown) disposed in the gap space 212. The reformer 22, the plurality of fuel cells 23, the partition wall 28, and the heat insulating member 29 are accommodated in the internal space 272 of the lining portion 27 (that is, the internal space of the outer wall portion 271).

  The partition wall portion 28 is formed of a heat conductive material having higher heat conductivity than the above-described heat insulating material forming the inner surface 211 of the housing 21, similarly to the outer wall portion 271. The partition wall 28 is formed of, for example, a relatively thin metal plate. The partition wall 28 is made of the same material as the outer wall 271, for example. The partition wall 28 may be formed of a material different from that of the outer wall 271. The partition wall portion 28 is supported by the outer wall portion 271 in the internal space 272.

  The partition wall portion 28 is connected to the outer wall portion 271 so as to be able to conduct heat. For example, the partition wall portion 28 is joined to the inner surface of the outer wall portion 271 by welding. The partition wall 28 divides the internal space 272 of the lining 27 into a reformer placement area 281 and a plurality of battery placement areas 282. In the reformer placement area 281, the reformer 22 is placed. A plurality of fuel cells 23 are dispersedly arranged in the plurality of battery arrangement areas 282. In the example shown in FIG. 1, the number of the plurality of battery arrangement areas 282 is 12, and the number of the fuel cells 23 arranged in each of the plurality of battery arrangement areas 282 is one.

  In the example shown in FIG. 1, in the internal space 272 of the lining portion 27, a plurality of battery chambers 283 that separate each of the plurality of battery placement areas 282 from each other are formed by the partition wall portion 28. Each battery chamber 283 has, for example, a substantially rectangular parallelepiped shape, and the internal space of each battery chamber 283 serves as a battery placement area 282. The upper and lower surfaces of the battery chamber 283 are substantially parallel to the upper and lower surfaces of the outer wall portion 271. The side surface of the battery chamber 283 is substantially parallel to the side surface of the outer wall portion 271. In the example shown in FIG. 1, the four battery chambers 283 on the right side of the internal space 272 are formed by the partition wall portion 28 and the outer wall portion 271. Two side surfaces of each battery chamber 283 that are not displayed in FIG. 1 (that is, the front side surface and the back side surface in FIG. 1) may be a part of the partition wall part 28 or a part of the outer wall part 271. It may be. The shapes and sizes of the plurality of battery chambers 283 are approximately the same, and the positions of the fuel cells 23 in the plurality of battery chambers 283 are also approximately the same.

  The upper surface, the lower surface, and the two side surfaces displayed in FIG. 1 of each battery chamber 283 constitute a cylindrical portion that extends in a direction perpendicular to the paper surface of FIG. That is, the plurality of battery chambers 283 include a plurality of the cylindrical portions, respectively. The plurality of cylindrical portions are each, for example, a substantially square cylindrical shape. The plurality of cylindrical portions are formed by the partition walls 28 and surround the plurality of battery placement areas 282, respectively. In the example shown in FIG. 1, the four cylindrical portions on the right side of the internal space 272 are formed by a partition wall portion 28 and an outer wall portion 271.

  In each battery chamber 283, the fuel cell 23 is supported on the lower surface of the battery chamber 283 (that is, a part of the partition wall portion 28) via the heat insulating member 29. In other words, the plurality of fuel cells 23 are indirectly supported by the lining portion 27 via the heat insulating member 29.

  Each of the plurality of fuel cells 23 is a solid oxide fuel cell (SOFC), for example, a cell stack in which a plurality of cells (unit cells) (not shown) are stacked. Fuel gas is supplied to the negative electrode (anode) of each fuel cell 23, and oxidant gas is supplied to the positive electrode (cathode). Thereby, an electrochemical reaction occurs in each fuel cell 23, and power generation is performed. The electrochemical reaction in the fuel cell 23 is an exothermic reaction, and the generated heat is used for heating the reformer 22 or the like. The power generation by the fuel cell 23 is performed at a high temperature of 600 to 1000 degrees, for example. The fuel gas is, for example, hydrogen gas, and the oxidant gas is, for example, oxygen gas.

  The reformer 22 is connected to a raw fuel supply source 48 disposed outside the housing 21 via a raw fuel supply pipe 261. On the raw fuel supply pipe 261, an impurity removing unit 41 and a first heat exchanger 42 are provided. The impurity removing unit 41 removes impurities (for example, sulfur-based impurities and nitrogen-based impurities) from the raw fuel supplied from the raw fuel supply source 48 to the reformer 22.

  The reformer 22 reforms the raw fuel to generate a reformed gas containing a fuel gas. As the raw fuel, for example, LP gas, city gas, natural gas, kerosene, biogas, bioethanol and the like are used. In the reformer 22, the raw fuel is reformed by, for example, a steam reforming method, a partial oxidation reforming method, an autothermal reforming method, or the like. In the example shown in FIG. 1, the reformer 22 reforms the LP gas as the raw fuel at a high temperature by the steam reforming method, and generates a reformed gas containing hydrogen gas as the fuel gas. The reformed gas from the reformer 22 is guided to the plurality of battery chambers 283 by the fuel gas supply pipe 251 and supplied to the respective negative electrodes of the plurality of fuel cells 23.

  In FIG. 1, in order to simplify the drawing, the illustration of the vicinity of the connection portion with the plurality of fuel cells 23 in the fuel gas supply pipe 251 is omitted. The same applies to the negative exhaust gas exhaust pipe 252, the oxidant gas supply pipe 253, and the positive exhaust gas exhaust pipe 254 described later. FIG. 2 shows how each fuel cell 23 is connected to the fuel gas supply pipe 251, the negative exhaust gas exhaust pipe 252, the oxidant gas supply pipe 253, and the positive exhaust gas exhaust pipe 254. In FIG. 2, one fuel cell 23 is shown as a representative, but the connection mode of the other fuel cells 23 is the same as that in FIG. In FIG. 2, another configuration (that is, the reformer 22) connected to the fuel cell 23 through the fuel gas supply pipe 251, the negative exhaust gas exhaust pipe 252, the oxidant gas supply pipe 253, and the positive exhaust gas exhaust pipe 254. The blower 43, the condensing part 45, and the exhaust gas combustion part 47) are also shown.

  The reformed gas generated by the reformer 22 shown in FIG. 1 is supplied to each negative electrode of the plurality of fuel cells 23 via the fuel gas supply pipe 251. Negative electrode exhaust gas, which is a gas discharged from each negative electrode of the plurality of fuel cells 23, is discharged out of the housing 21 through the negative electrode exhaust gas discharge pipe 252. The negative electrode exhaust gas includes water vapor generated when hydrogen gas, which is a fuel gas, is used for power generation in the fuel cell 23, and unused fuel gas that has not been used for power generation in the fuel cell 23.

  The negative exhaust gas discharged from the negative electrodes of the plurality of fuel cells 23 is led to the first heat exchanger 42 through the negative exhaust gas exhaust pipe 252. In the first heat exchanger 42, the raw fuel supplied from the raw fuel supply source 48 to the reformer 22 is preheated using the high temperature negative exhaust gas flowing through the negative exhaust gas exhaust pipe 252.

  The negative exhaust gas that has passed through the first heat exchanger 42 is guided to the condensing unit 45 by the negative exhaust gas exhaust pipe 252. In the condensing part 45, the water vapor | steam in a negative electrode waste gas is condensed and water is produced | generated. The water generated by the condensing unit 45 is supplied to the water vapor generating unit 46 through the water supply pipe 451. In the water vapor generation unit 46, water is heated to generate water vapor. The water vapor generated by the water vapor generator 46 is guided to the raw fuel supply pipe 261 via the water vapor supply pipe 262, and is supplied to the reformer 22 together with the raw fuel that has passed through the impurity removal section 41. Used for reforming. On the other hand, the negative electrode exhaust gas that has passed through the condensing unit 45 is guided to the exhaust gas combustion unit 47.

  Each positive electrode of the plurality of fuel cells 23 is connected to a blower 43 disposed outside the housing 21 by an oxidant gas supply pipe 253. Air including oxygen gas, which is an oxidant gas, is supplied to the positive electrodes of the plurality of fuel cells 23 via the oxidant gas supply pipe 253 by the blower 43. Positive exhaust gas that is gas discharged from each positive electrode of the plurality of fuel cells 23 is discharged out of the housing 21 through a positive exhaust gas discharge pipe 254. The positive exhaust gas exhaust pipe 254 passes through the second heat exchanger 44 provided on the oxidant gas supply pipe 253. In the second heat exchanger 44, the air supplied to each fuel cell 23 is preheated using the high temperature positive exhaust gas discharged from the positive electrodes of the plurality of fuel cells 23 and flowing through the positive exhaust gas exhaust pipe 254.

  The positive exhaust gas exhaust pipe 254 that has passed through the second heat exchanger 44 joins the negative exhaust gas exhaust pipe 252 outside the housing 21 at a junction 471 before (that is, upstream) the exhaust gas combustion unit 47. At the junction 471, the negative exhaust gas that has passed through the condensing unit 45 and the positive exhaust gas that has passed through the second heat exchanger 44 merge. In the exhaust gas combustion section 47, the merged negative electrode exhaust gas and positive electrode exhaust gas are combusted. Thereby, unused fuel gas etc. which are contained in anode exhaust gas are burned. The combustion heat generated in the exhaust gas combustion unit 47 may be used for, for example, heating of water in the steam generation unit 46 or power generation using a turbine. Further, the exhaust gas combustion part 47 may be provided in the housing 21, and the combustion heat of the exhaust gas combustion part 47 may be used for heating the reformer 22 or the like. For example, a catalytic combustor is used as the exhaust gas combustion unit 47.

  In the steady operation of the fuel cell system 1, as described above, power generation is performed using the fuel gas and the oxidant gas in each of the plurality of fuel cells 23. Heat generated during power generation in the plurality of fuel cells 23 is applied to the reformer 22 via the lining portion 27. Specifically, heat from the plurality of fuel cells 23 is transmitted to the lining portion 27 by radiation or the like, and is transmitted to the reformer 22 disposed in the reformer placement area 281 by radiation or the like. The heat applied from the plurality of fuel cells 23 to the reformer 22 is used for steam reforming of the raw fuel in the reformer 22.

  Further, in the steady operation of the fuel cell system 1, as described above, the raw fuel supplied to the reformer 22 is preheated using the negative electrode exhaust gas discharged from the plurality of fuel cells 23, and a plurality of Preheating of the air supplied to each fuel cell 23 is performed using the positive electrode exhaust gas discharged from each of the fuel cells 23. Thereby, in the fuel cell system 1, the steady operation can be performed without applying heat required in the system during the steady operation from outside the system. Further, in the fuel cell system 1, by using the water vapor contained in the negative electrode exhaust gas for the steam reforming performed in the reformer 22, the water required in the system during steady operation is given from outside the system. The steady operation can be performed without any problem. In other words, in the fuel cell system 1 during the steady operation, the heat independent operation and the water independent operation are possible.

  Next, the start-up operation (so-called cold start) of the fuel cell system 1 will be described. The start-up operation of the fuel cell system 1 is to change the state of the fuel cell system 1 from a stopped state to a steady operation state in which power generation is constantly performed.

  The water supply unit 31 and the heating fluid generation unit 33 are also used for the start-up operation of the fuel cell system 1. The water supply unit 31 stores water and supplies the water to the reformer 22 of the fuel cell system 1 when the fuel cell system 1 is activated. The water supply unit 31 includes, for example, a water storage unit 311, a pump 312, and an activation water supply pipe 313. The water storage unit 311 is a tank that stores water (for example, pure water). The water storage unit 311 is connected to the water vapor generation unit 46 of the fuel cell system 1 via the startup water supply pipe 313. The pump 312 is provided on the activation water supply pipe 313 and supplies water stored in the water storage unit 311 to the water vapor generation unit 46.

  The heating fluid generation unit 33 is connected to the raw fuel supply source 48 via the impurity removal unit 41 by the raw fuel supply pipe 255. The heating fluid generator 33 is also connected to the blower 43 via a gas supply pipe 256. In the heating fluid generator 33, the raw fuel (for example, LP gas, city gas, natural gas, kerosene, biogas, bioethanol) supplied from the raw fuel supply source 48 is supplied from the blower 43 (for example, , Air), and a relatively high temperature gas (hereinafter referred to as “heating gas”) is generated. As the heating fluid generator 33, for example, a catalytic combustor is used.

  The heating gas that is the heating fluid generated by the heating fluid generation unit 33 is supplied to the gap space 212 from the heating fluid supply pipe 257 and the supply port 213. The heating gas spreads over the entire gap space 212 and is discharged from the discharge port 214 to the outside of the housing 21 through the heating fluid discharge pipe 258. Note that during the start-up operation of the fuel cell system 1, the decompression unit 51 is stopped.

  In the fuel cell system 1, the heating gas is continuously supplied from the heating fluid generation unit 33 to the gap space 212, and the entire outer surface of the outer wall portion 271 of the lining portion 27 is in contact with the high-temperature heating gas. The outer wall portion 271 is quickly heated. Further, the partition wall portion 28 connected to the outer wall portion 271 so as to be capable of conducting heat is also quickly heated by heat conduction from the outer wall portion 271. As a result, the temperature of the lining portion 27 is raised substantially evenly. In the internal space 272 of the lining portion 27, the reformer 22 arranged in the reformer arrangement area 281 is heated by the radiation from the lining portion 27 to be heated. In addition, the plurality of fuel cells 23 arranged in the plurality of battery chambers 283 are heated substantially uniformly by the radiation from the plurality of battery chambers 283 (that is, radiation from the lining portion 27) to increase the temperature.

  Subsequently, the raw fuel from the raw fuel supply source 48 passes through the impurity removal unit 41 and is supplied to the reformer 22. Further, water from the water supply unit 31 is supplied to the steam generation unit 46, converted into water vapor by the steam generation unit 46, and then supplied to the reformer 22. The raw fuel is steam reformed by the reformer 22 to generate a reformed gas containing fuel gas, which is supplied to the negative electrodes of the plurality of fuel cells 23. Air containing an oxidant gas is supplied to the positive electrodes of the plurality of fuel cells 23 by the blower 43 described above. As a result, power generation by the plurality of fuel cells 23 is performed, and the reformer 22 is further heated by heat generated during power generation. Further, the water generated in the condensing unit 45 from the negative electrode exhaust gas from the plurality of fuel cells 23 is supplied to the water vapor generating unit 46.

  In the fuel cell system 1, until the reformer 22 and the plurality of fuel cells 23 reach a predetermined temperature and the outputs from the plurality of fuel cells 23 reach a predetermined power generation amount and become stable, that is, the fuel cell system 1 The start-up operation described above is continued until the steady operation state is reached. When steady operation of the fuel cell system 1 is started and the above-described water self-sustainment and heat self-sustainment are established, the supply of water from the water supply unit 31 to the water vapor generation unit 46 is stopped, and the gap fluid 212 from the heating fluid generation unit 33 is stopped. The supply of the heating gas to is stopped.

  During steady operation of the fuel cell system 1, the gas in the gap space 212 is sucked by the decompression unit 51, so that the gap space 212 has a reduced pressure atmosphere lower than the pressure during the startup operation. Preferably, the pressure in the gap space 212 is set to a pressure lower than the atmospheric pressure by the decompression unit 51. Thereby, it is possible to suppress the heat of the internal space 272 of the lining portion 27 from being transmitted to the outside of the lining portion 27 via the gas in the gap space 212. In other words, heat radiation from the internal space 272 of the lining portion 27 can be suppressed. For this reason, the temperature of the internal space 272 of the lining portion 27 can be easily maintained at a predetermined target temperature, and the temperatures of the reformer 22 and the plurality of fuel cells 23 can be easily maintained at desired temperatures. it can. As a result, suitable power generation by the plurality of fuel cells 23 can be realized.

  During steady operation of the fuel cell system 1, the temperature of the internal space 272 of the lining portion 27 is continuously measured by a temperature sensor or the like provided in the housing 21. Based on the temperature of the internal space 272, the pressure controller 52 controls the decompression unit 51 to adjust the pressure (that is, the degree of vacuum) in the gap space 212. Specifically, when the temperature of the internal space 272 is higher than the target temperature, the suction by the decompression unit 51 is reduced and the pressure of the gap space 212 is increased. Thereby, heat radiation from the internal space 272 to the outside increases, and the temperature of the internal space 272 decreases to the target temperature. On the other hand, when the temperature of the internal space 272 is lower than the target temperature, the suction by the decompression unit 51 is increased and the pressure of the gap space 212 is decreased. Thereby, the heat radiation from the internal space 272 is reduced, and the temperature of the internal space 272 increases to the target temperature.

  As described above, the pressure control unit 52 controls the decompression unit 51 based on the temperature of the internal space 272, so that the heat radiation from the internal space 272 of the lining portion 27 can be further suitably suppressed. As a result, the temperature of the internal space 272, the reformer 22, and the plurality of fuel cells 23 can be easily and accurately maintained at a desired temperature, and more preferable power generation by the plurality of fuel cells 23 can be realized. In the fuel cell system 1, the control of the decompression unit 51 by the pressure control unit 52 may be performed substantially based on the temperature of the internal space 272, and has a correlation with the temperature of the internal space 272, for example. You may perform based on the electric power generation amount (namely, system output) of the fuel cell system 1. FIG.

  As described above, in the fuel cell system 1, the inner surface 211 of the housing 21 is formed of a heat insulating material, and the lining portion 27 is formed of a heat conductive material having higher heat conductivity than the heat insulating material. The lining portion 27 covers the inner surface 211 while being separated from the inner surface 211 of the housing 21 and accommodates the plurality of fuel cells 23 in the internal space 272. During the start-up operation of the fuel cell system 1, a heating gas that is a heating fluid is supplied to the gap space 212 between the housing 21 and the lining portion 27, and a plurality of fuel cells are irradiated by radiation from the lining portion 27. 23 is heated. Thereby, the difference of the temperature increase rate resulting from the position in the internal space 272 of the some fuel cell 23 can be suppressed, and the some fuel cell 23 can be heated up substantially equally.

  In the fuel cell system 1, the lining portion 27 includes an outer wall portion 271 that covers the inner surface 211 while being separated from the inner surface 211 of the housing 21, and a partition wall portion 28 that is connected to the outer wall portion 271 so as to be capable of conducting heat. The partition wall 28 divides the internal space 272 of the lining portion 27 into a plurality of battery placement areas 282 in which the plurality of fuel cells 23 are arranged in a distributed manner. As a result, the difference between the shortest distances between the plurality of fuel cells 23 and the lining portion 27 is reduced, and the uniformity of heat applied to the plurality of fuel cells 23 due to radiation from the lining portion 27 is reduced. improves. As a result, it is possible to further suppress the difference in the temperature increase rate of the plurality of fuel cells 23 and improve the temperature increase uniformity of the plurality of fuel cells 23.

  As described above, in the fuel cell system 1, a plurality of cylindrical portions that respectively surround the plurality of cell placement areas 282 are formed by the partition wall portions 28. Thus, by surrounding the fuel cells 23 arranged in each cell arrangement area 282 with the heat conductive material, the plurality of fuel cells 23 can be efficiently heated. Further, in each fuel cell 23, the heat generated by the radiation from the cylindrical portion is applied substantially evenly to the portion facing the cylindrical portion, so that the temperature of the entire fuel cell 23 can be increased substantially uniformly. . Specifically, for example, in each fuel cell 23, the temperature of the negative electrode and the positive electrode is increased substantially evenly.

  Further, in the fuel cell system 1, a plurality of battery chambers 283 that respectively include the above-described plurality of cylindrical portions and isolate the plurality of battery placement areas 282 from each other are formed by the partition wall portions 28. Thus, by surrounding the entire periphery of the fuel cell 23 arranged in each cell arrangement area 282 with the heat conductive material, the plurality of fuel cells 23 can be heated more efficiently. Further, in each fuel cell 23, heat from radiation from the battery chamber 283 is applied substantially evenly to a portion facing the battery chamber 283, so that the uniformity of temperature rise of each fuel cell 23 can be improved. it can.

  As described above, in the fuel cell system 1, the number of the fuel cells 23 arranged in each of the plurality of cell arrangement areas 282 is one. For this reason, the heat applied from the lining portion 27 to each battery placement area 282 by radiation is used to raise the temperature of one fuel cell 23 placed in the battery placement area 282 and the rise of the other fuel cells 23 is increased. Virtually not used for temperature. Therefore, it is possible to further improve the uniformity of the temperature rise of the plurality of fuel cells 23. Further, as described above, the shapes and sizes of the plurality of battery chambers 283 are approximately the same, and the positions of the fuel cells 23 in the plurality of battery chambers 283 are also approximately the same. Thereby, the uniformity of the temperature rise of the plurality of fuel cells 23 can be further improved.

  As described above, the lining portion 27 supports the plurality of fuel cells 23 via the heat insulating member 29. For this reason, heat transfer from the lining portion 27 to the plurality of fuel cells 23 is suppressed, and the plurality of fuel cells 23 are heated mainly by heat transfer due to radiation from the lining portion 27. Thereby, the difference in the heat conduction caused by the difference in the contact state between the fuel cell 23 and the lining 27, the difference in the distance between the gap space 212 through which the heating fluid flows and the fuel cell 23, and the like are suppressed, The uniformity of the temperature rise of the plurality of fuel cells 23 can be improved. Further, in each fuel cell 23, there is no portion in direct contact with the lining portion 27 (that is, the entire fuel cell 23 is not in contact with the lining portion 27). Uniformity can also be improved.

  FIG. 3 is a diagram showing a configuration of a fuel cell system 1a according to the second embodiment of the present invention. In the fuel cell system 1a, a working fluid supply unit 53 and a third heat exchanger 54 are provided instead of the decompression unit 51 and the pressure control unit 52 shown in FIG. The other configuration of the fuel cell system 1a is substantially the same as that of the fuel cell system 1 shown in FIG. 1, and the same reference numerals are given to the corresponding components of the fuel cell system 1a in the following description.

  The working fluid supply unit 53 is connected to the supply port 213 via the working fluid supply pipe 531. The working fluid supply unit 53 supplies the working fluid to the gap space 212 via the working fluid supply pipe 531 and the supply port 213 during the steady operation of the fuel cell system 1a. The working fluid spreads over the entire gap space 212 and is heated via the lining portion 27 by heat from the plurality of fuel cells 23. The working fluid heated while passing through the gap space 212 is discharged from the discharge port 214 to the outside of the housing 21. The working fluid may be a gas or a liquid. As the working fluid, for example, an inert gas such as nitrogen or air, or an organic medium such as water or alternative chlorofluorocarbon is used. When an inert gas is used as the working fluid, for example, carbon dioxide having a relatively high thermal conductivity is preferably used as the working fluid. The working fluid discharged from the discharge port 214 may be circulated to the supply port 213 via the working fluid supply pipe 531.

  The third heat exchanger 54 is disposed on the water supply pipe 451 between the condensing unit 45 and the water vapor generating unit 46. The third heat exchanger 54 is connected to the discharge port 214 via the working fluid discharge pipe 541. The relatively high temperature working fluid discharged from the gap space 212 via the discharge port 214 is guided to the third heat exchanger 54 via the working fluid discharge pipe 541. In the third heat exchanger 54, water supplied from the condensing unit 45 to the water vapor generating unit 46 during steady operation of the fuel cell system 1a is heated by the working fluid. The third heat exchanger 54 may be disposed on the steam supply pipe 262 between the steam generator 46 and the reformer 22. In this case, the steam supplied from the steam generator 46 to the reformer 22 is heated by the working fluid in the third heat exchanger 54.

  In any case, the third heat exchanger 54 is supplied to the reformer 22 using the working fluid heated through the gap space 212 during the steady operation of the fuel cell system 1a. Water is heated. Thereby, during the steady operation of the fuel cell system 1a, the exhaust heat released from the lining portion 27 to the outside is effectively used to heat the water in the steam generation unit 46 or to perform the steam reforming in the reformer 22. The energy required can be reduced.

  The third heat exchanger 54 may be provided on the raw fuel supply pipe 261 between the reformer 22 and the impurity removal unit 41, for example. In this case, in the third heat exchanger 54, during the steady operation of the fuel cell system 1a, the raw fuel supplied to the reformer 22 is preheated using the working fluid heated through the gap space 212. Is done. Thereby, during the steady operation of the fuel cell system 1a, exhaust heat released from the lining portion 27 to the outside can be effectively used, and the energy required for steam reforming in the reformer 22 can be reduced.

  For example, the third heat exchanger 54 may be provided on the oxidant gas supply pipe 253 between the blower 43 and the plurality of fuel cells 23. In this case, in the third heat exchanger 54, during the steady operation of the fuel cell system 1a, the working fluid heated through the gap space 212 is used to supply the oxidant gas supplied to the plurality of fuel cells 23. Preheating is performed. Thereby, during the steady operation of the fuel cell system 1a, the exhaust heat released from the lining portion 27 to the outside can be effectively used, and the energy required for heating the oxidant gas can be reduced.

  In the fuel cell system 1a, a turbine and a generator are provided instead of the third heat exchanger 54, and the working fluid heated through the gap space 212 is driven to drive the turbine and the generator. Power generation may be performed. Thereby, during the steady operation of the fuel cell system 1a, the exhaust heat released from the lining portion 27 to the outside can be effectively used, and the power generation amount of the fuel cell system 1a can be increased.

  FIG. 4 is a diagram showing a configuration of a fuel cell system 1b according to the third embodiment of the present invention. In the fuel cell system 1b, a supply switching unit 55 is provided instead of the decompression unit 51 and the pressure control unit 52 shown in FIG. The other configuration of the fuel cell system 1b is substantially the same as that of the fuel cell system 1 shown in FIG. 1, and the same reference numerals are given to the corresponding components of the fuel cell system 1b in the following description.

  The supply switching unit 55 is provided on the oxidant gas supply pipe 253 that guides the oxidant gas from the blower 43 to the plurality of fuel cells 23. The supply switching unit 55 is provided between the second heat exchanger 44 and the housing 21, for example. In the supply switching unit 55, the oxidant gas supply pipe 253 a branches from the oxidant gas supply pipe 253 and is connected to the first oxidant gas supply port 215 provided in the housing 21. A second oxidant gas supply port 216 is provided on the outer wall portion 271 of the lining portion 27. The second oxidant gas supply port 216 is connected to the oxidant gas supply pipe 253 via the oxidant gas supply pipe 253 b in the internal space 272 of the lining portion 27.

  During the start-up operation of the fuel cell system 1b, as described above, the oxidant gas from the blower 43 is guided to the internal space 272 of the lining portion 27 by the oxidant gas supply pipe 253 and supplied to the plurality of fuel cells 23. Is done. The gap space 212 is supplied with a high-temperature heating gas from the heating fluid generator 33. When the startup operation of the fuel cell system 1b is finished and the steady operation is performed, the supply of the heating gas to the gap space 212 is stopped.

  During the steady operation of the fuel cell system 1b, the flow path is switched by the supply switching unit 55, whereby the oxidant gas from the blower 43 is guided to the oxidant gas supply pipe 253a and the first oxidant gas supply port. It is supplied to the gap space 212 via 215. The oxidant gas spreads over the entire gap space 212 and is heated through the lining portion 27 by heat from the plurality of fuel cells 23. The oxidant gas heated in the gap space 212 is guided to the oxidant gas supply pipe 253 in the inner space 272 of the lining portion 27 through the second oxidant gas supply port 216 and the oxidant gas supply pipe 253b. Then, it is supplied to the plurality of fuel cells 23 via the oxidant gas supply pipe 253. As described above, when the oxidant gas is supplied to the plurality of fuel cells 23 via the gap spaces 212 during the steady operation of the fuel cell system 1b, the exhaust heat released from the lining portion 27 to the outside is reduced. The oxidant gas can be preheated effectively.

  Various modifications can be made in the above-described fuel cell systems 1, 1a, 1b.

  For example, in the fuel cell systems 1, 1 a, 1 b, the heating fluid supplied from the heating fluid generator 33 to the gap space 212 is not necessarily limited to the heating gas, but a heating liquid (for example, a high It may be a flame-retardant machine oil having a boiling point. The heating fluid generator 33 may be, for example, an electric heater that heats the heating fluid.

  In the fuel cell systems 1, 1 a, 1 b, the number of the fuel cells 23 arranged in each of the plurality of cell arrangement areas 282 in the internal space 272 of the lining portion 27 may be two or more. Further, the number of fuel cells 23 arranged in each of the plurality of battery arrangement areas 282 may be different. The heat insulating member 29 between the fuel cell 23 and the lining portion 27 may be omitted.

  In the fuel cell systems 1, 1 a, 1 b, the above-described tubular portion surrounding the cell placement area 282 is not necessarily limited to a rectangular tubular shape, and may have various shapes. The cylindrical portion may be cylindrical, for example. Alternatively, battery chambers 283 including a plurality of cylindrical portions each having a hexagonal cylindrical shape may be arranged in a honeycomb shape. In the fuel cell system 1 shown in FIG. 1, the front and back side surfaces in FIG. 1 are omitted from the plurality of battery chambers 283, and the plurality of cylindrical portions are arranged in the internal space 272 of the lining portion 27. Also good. The same applies to the fuel cell systems 1a and 1b.

  In the fuel cell systems 1, 1 a, and 1 b, if the inner space 272 of the lining portion 27 is partitioned into a plurality of battery placement areas 282 by the partition wall portion 28, the above-described cylindrical portion may not be provided. Further, the partition wall 28 may be omitted.

  In the fuel cell systems 1, 1 a, 1 b, the lining portion 27 does not necessarily need to cover the entire inner surface 211 of the housing 21 and does not have to be a substantially rectangular parallelepiped casing. For example, the lining portion 27 has a substantially rectangular tube shape that opens to the side, and may cover the upper surface, the lower surface, and the two side surfaces of the inner surface 211 of the substantially rectangular parallelepiped housing 21 while being separated from the inner surface 211. . That is, the lining portion 27 only needs to cover at least a part of the inner surface 211 while being separated from the inner surface 211 of the housing 21.

  During the starting operation of the fuel cell systems 1, 1 a, 1 b, a starting material different from the raw fuel may be supplied to the reformer 22. As the starting material, for example, nitrogen, hydrogen, LP gas, city gas, bioethanol or the like is used. The reformer 22 is not necessarily accommodated in the internal space 272 of the lining portion 27, and may be disposed in the gap space 212, for example.

  In the fuel cell systems 1, 1 a, 1 b, the water vapor contained in the negative electrode exhaust gas from the fuel cell 23 is taken out as water by the condensing unit 45 and then supplied to the water vapor generating unit 46. A part of the gas may be supplied to the reformer 22 in a gaseous state. Even in this case, it is possible to realize water self-sustained operation during steady operation.

  In the fuel cell systems 1, 1 a, and 1 b, it is not always necessary to perform water self-sustained operation during steady operation, and water may be continuously supplied from the water supply unit 31 to the steam generation unit 46. In the fuel cell systems 1, 1 a, and 1 b, it is not always necessary to perform the heat independent operation during the steady operation, and the heating fluid is continuously supplied from the heating fluid generator 33 to the gap space 212. Also good. In this case, the decompression unit 51 and the pressure control unit 52 shown in FIG. 1, the working fluid supply unit 53 and the third heat exchanger 54 shown in FIG. 3, and the supply switching unit 55 shown in FIG. 4 may be omitted.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1, 1a, 1b Fuel cell system 21 Housing 22 Reformer 23 Fuel cell 27 Lining part 28 Partition part 29 Heat insulation member 51 Pressure-reducing part 52 Pressure control part 53 Working fluid supply part 211 (Housing) inner surface 212 Gap space 272 ( Internal space (liner) 282 Battery placement area 283 Battery compartment

Claims (10)

A fuel cell system,
A reformer that reforms raw fuel to produce fuel gas;
A plurality of solid oxide fuel cells, each generating power using the fuel gas and oxidant gas;
A housing whose inner or outer surface is formed of a heat insulating material;
A lining portion that is formed of a heat conductive material having higher heat conductivity than the heat insulating material, covers the inner surface while being separated from the inner surface of the housing, and houses the plurality of fuel cells in an internal space;
With
During start-up operation, a heating fluid is supplied to a gap space between the housing and the lining portion, and the plurality of fuel cells are heated by radiation from the lining portion. . The fuel cell system according to claim 1,
The lining is
An outer wall portion covering the inner surface while being separated from the inner surface of the housing;
A partition wall portion that is connected to the outer wall portion so as to be capable of conducting heat, and divides the inner space into a plurality of cell arrangement areas in which the plurality of fuel cells are distributed and arranged,
A fuel cell system comprising: The fuel cell system according to claim 2, wherein
The fuel cell system, wherein the partition wall portion forms a plurality of cylindrical portions respectively surrounding the plurality of battery arrangement areas. The fuel cell system according to claim 3,
A fuel cell system comprising: a plurality of battery chambers each including the plurality of cylindrical portions and isolating each of the plurality of battery arrangement areas from each other by the partition wall portion. The fuel cell system according to any one of claims 2 to 4,
The fuel cell system, wherein the number of fuel cells arranged in each of the plurality of cell arrangement areas is one. A fuel cell system according to any one of claims 1 to 5,
The fuel cell system, wherein the lining portion supports the plurality of fuel cells via a heat insulating member. The fuel cell system according to any one of claims 1 to 6,
A fuel cell system, further comprising a decompression unit that makes the gap space a decompressed atmosphere during steady operation. The fuel cell system according to claim 7, wherein
The fuel cell system further comprising a pressure control unit that controls the pressure reducing unit to adjust the pressure in the gap space based on the temperature of the internal space of the lining. The fuel cell system according to any one of claims 1 to 6,
A working fluid supply unit for supplying the working fluid to the gap space during steady operation;
The working fluid heated through the gap space is used to heat water supplied to the reformer, to preheat the raw fuel supplied to the reformer, or to A fuel cell system, wherein the oxidant gas supplied to the fuel cell is preheated. The fuel cell system according to any one of claims 1 to 6,
The fuel cell system according to claim 1, wherein the oxidant gas is supplied to the plurality of fuel cells via the gap space during steady operation.

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