JP4942292B2 - Power generator - Google Patents

Description

  The present invention relates to an apparatus for generating electricity by a fuel cell using a solid oxide.

A fuel cell using a solid oxide has high efficiency and is expected to be suitable for a power generation apparatus of several kilowatts to several tens of kilowatts.
Since a fuel cell using a solid oxide efficiently generates power in a high temperature environment of about 800 ° C., it is important to maintain the temperature of the room containing the fuel cell group at a high temperature of about 800 ° C. When the temperature of the cell group storage chamber decreases, the power generation efficiency decreases.
A fuel cell using a solid oxide uses a fuel gas containing hydrocarbons such as methane, ethane, ethylene, propane and butane. These hydrocarbon fuel gases are decomposed into carbon monoxide and hydrogen. Solid oxide fuel cells generate electricity by reacting a reformed gas containing hydrogen and carbon monoxide with an aerobic gas (for example, air). The reforming reaction of the fuel gas is an endothermic reaction, and it is necessary to continue heating the reformer in order to maintain the reforming reaction.
In order to maintain the fuel cell group at an appropriate power generation temperature of about 800 ° C. and to maintain the reformer at an appropriately high temperature reforming temperature, a technology for accommodating the fuel cell group and the reformer in the same room is proposed. This is disclosed in Patent Document 1. However, Patent Document 1 has not been disclosed yet.

The reformed gas and the aerobic gas sent into the cell group accommodation chamber generate electricity by reacting. The reaction is an exothermic reaction, and the fuel cell group and the reformer can be heated by utilizing the exothermic reaction.
Due to its characteristics, the fuel cell cannot consume all of the reformed gas fed in, and the amount of reformed gas (off-gas) that passes through the fuel cell cannot be reduced to zero. Combustion heat can be obtained by burning off-gas that cannot be reduced to zero, and the fuel cell group and the reformer can be heated by using the combustion heat.

In the technique of Patent Document 1, a cell stack is configured by aligning a plurality of fuel cells in a straight line. In the technique of Patent Document 1, a plurality of cell stacks are used. Off-gas that cannot be reduced to zero is blown out from the tip of each cell stack, and an off-gas combustor is formed there. The plurality of cell stacks are arranged substantially parallel to each other at intervals. At this time, the off-gas combustor group provided at the front end of the cell stack is arranged so as to be located in substantially the same plane.
The reformer is disposed so as to be substantially parallel to the plane on which the off-gas combustor group is located.

According to the technique of Patent Document 1, the combustion heat of off-gas that cannot be reduced to zero can be efficiently used for heating the reformer. Further, the heat generated by the power generation reaction and the combustion heat of the off gas can be efficiently used for heating the cell stack group.
With only the heat generated by the power generation reaction and the off-gas combustion heat that cannot be reduced to zero, the cell stack group can be heated to a suitable temperature for power generation and the reformer can be heated to a suitable temperature for reforming. The fact that fuel is not needed is called “thermal independence”. The power generation device of Patent Document 1 has succeeded in making heat self-sustained by efficiently using the heat generated by the power generation reaction and the combustion heat of off-gas.

Japanese Patent Application No. 2004-41937

The power generation device of Patent Document 1 has high thermal efficiency and succeeds in thermal independence. However, it has been found that there is a problem that the temperature distribution of the reformer is difficult to be uniform.
The reformer has a surface facing the off-gas combustor group. The surface is heated with off-gas combustion heat. The distance between the front surface and the back surface is set small so that the temperature difference between the heated front surface side and the unheated back surface side becomes small. The reformer is formed in a flat box shape, and is designed so as to reduce the temperature difference between the heated front side and the unheated back side by utilizing a wide heating surface and flatness.
However, it is still difficult to sufficiently reduce the temperature difference between the heated front side and the unheated back side. If the front side is adjusted to an appropriate temperature for reforming, the reforming efficiency is lowered due to insufficient temperature on the back side, and if the rear side is adjusted to the proper reforming temperature, the surface side is overheated and the reforming efficiency is lowered.
An object of the present invention is to homogenize the temperature distribution of the reformer facing the off-gas combustor group.

The power generator of the present invention generates power using a solid oxide fuel cell. In the present invention, a cell stack is formed by forming one fuel cell in a straight line or arranging a plurality of fuel cells in a straight line. An off-gas combustor is formed at the tip of each cell stack. Use multiple cell stacks. The plurality of cell stacks are arranged substantially parallel to each other at intervals. At this time, it arrange | positions so that the off-gas combustor group provided in the front-end | tip of each cell stack may be located in the substantially same plane. The reformer is disposed substantially parallel to the plane on which the off-gas combustor group is located, and is heated by the off-gas combustor group. The reformer penetrates from the surface facing the off-gas combustor group to the opposite surface (that is, the back surface) so that the combustion gas circulates to the back surface side of the reformer and is also heated from the back surface side. A combustion gas passage is formed.
When a combustion gas passage that penetrates from the front surface facing the off-gas combustor group to the back surface is formed, the off-gas combustion gas enters the back surface side of the reformer and heats the reformer also from the back surface side. The temperature difference between the front side and the back side can be made sufficiently small, and the temperature distribution of the reformer can be homogenized. It becomes possible to maintain the entire reformer at a suitable reforming temperature.

In the power generation device of the present invention, the cell stacks are further arranged to extend horizontally, and when viewed from the longitudinal direction, the plurality of cell stacks are arranged in a matrix with intervals in the horizontal and vertical directions. Has been placed . Further , a combustion gas passage extending in the vertical direction is formed in the reformer.
According to the above configuration, not only the temperature distribution is homogenized, but also the heating efficiency is improved.

In the above power generation device is a reformer flat box shape, it is preferable that the combustion gas passage is formed to penetrate the flat rear surface from the flat surface of the reformer.
According to the arrangement, when used in the reformer is opposed to the off-gas combustor group, is also heated from the back surface in the combustion gas is crowded around on the back, it is readily possible to obtain a homogeneous temperature distribution.

Hereinafter, preferred embodiments of the present invention will be described.
(Embodiment 1) The reformer is composed of an upper pipe and a lower pipe that are horizontally spaced apart from each other and a plurality of vertical pipes that communicate with each other.
(Mode 2) A plurality of cell stacks are arranged in a horizontal plane at intervals. A plurality of combustion gas passages extending in the vertical direction are formed in the reformer. Some off-gas combustors of the plurality of cell stacks face the combustion gas passage, and the remaining off-gas combustors face the reformer.

An embodiment of a power generator embodying the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view of a power generator according to the present embodiment, FIG. 2 is a sectional view taken along line II-II in FIG. 1, FIG. 3 is a sectional view taken along line III-III in FIG. 3 is a diagram schematically showing a piping system in a first chamber 44. FIG. As shown in FIGS. 1-3, the electric power generating apparatus is unitized.
As shown in FIGS. 1 to 4, the power generation unit 10 has a triple structure including a first chamber 44, a second chamber 46, and a third chamber 48 from the inner side toward the outer side. An inner partition wall 36 that partitions the first chamber 44 and the outer second chamber 46, an outer partition wall 38 that partitions the second chamber 46 and the outer third chamber 48, and an outer wall 40 that partitions the third chamber 48 from the outside. Have. The outer wall 40 is covered with a heat insulating member 42.
In the first chamber 44 in the central portion of the power generation unit 10, a cell stack 14 configured by aligning a plurality of fuel cells 12 in a straight line is accommodated. Each cell stack 14 is arranged so as to extend substantially in a horizontal plane, and seven cell stacks 14 extend in the same horizontal plane, and are provided in five stages in the vertical direction. Seven cell stack groups 14 are shown in order from the top, with suffixes a, b, c, d, and e. As apparent from FIG. 3, a total of 35 cell stacks 14 are arranged in a matrix of 7 in the horizontal direction and 5 in the vertical direction. As is clear from FIGS. 1 and 2, a total of 35 cell stacks 14 are paired on the left and right sides, and a total of 70 cell stacks 14 are accommodated in the first chamber 44. The left 35 cell stack group is referred to as 14L, and the right 35 cell stack group is referred to as 14R.
In the following, the left member is shown with a subscript L, the right member is shown with a subscript R, and the subscripts a, b, c, d, and e are added in order from the top. Common events are described in common with the subscripts omitted.
In the left half of the first chamber 44, there are 35 left cell stack groups 14L arranged in a matrix, a left reformer 18L that reforms the fuel gas into hydrogen, carbon monoxide, and the like. A manifold 24L that distributes the refined fuel gas to the 35 left cell stack groups 14L, and an air supply system 50La that supplies air (an example of an aerobic gas) to the outer surface of the 35 left cell stack groups 14L , 50Lb, 16La, 16Lb, 16Lc, 16Ld, 16Le, and the like.
In the right half of the first chamber 44, there are 35 right cell stack groups 14R arranged in a matrix, a right reformer 18R that reforms the fuel gas into hydrogen, carbon monoxide, and the like. A manifold 24R that distributes the refined fuel gas to the 35 right cell stack groups 14R, and air supply systems 50Ra, 50Rb, 16Ra, 16Rb that supply air to the outer surfaces of the 35 right cell stack groups 14R, 16Rc, 16Rd, 16Re, etc. are accommodated.

As shown in FIG. 5, the cross section of the fuel battery cell 12 is elliptical, and a little more than half of the circumferential surface of the fuel electrode 12a formed in the elliptical cylinder shape is covered with the solid electrolyte layer 12b, and the remaining circumferential surface is interfacing. Covered with a connector 12d, the oxygen electrode 12c covers the outside of the solid electrolyte layer 12b. Five reformed gas passages 20 penetrating in the longitudinal direction are formed in parallel inside the fuel electrode 12a.
The fuel electrode 12a is porous and is made of nickel / YSZ cermet (mixed sintered body) whose main component is nickel (Ni). The solid electrolyte layer 12b is dense and is made of a mixture obtained by adding yttria (Y2O3) to zirconia (ZrO2). The oxygen electrode 12c is porous and is made of LSM (La1-xSrxMnO3) which is a perovskite oxide. The interconnector 12d is made of a conductive ceramic.
A current collecting member 22 is interposed between the oxygen electrode 12 c of one cell 12 of the adjacent fuel battery cells 12 and the interconnector 12 d of the other cell 12. The current collecting member 22 is a conductive metal member folded in a bellows shape. The oxygen electrode of one cell 12 is electrically connected to the fuel electrode of the other cell 12 via the current collector 22 and the interconnector. A large number of cells 12 are connected in series to form a cell stack 14. The bellows-like current collecting member 22 does not prohibit the passage of air in the vertical direction in FIG.

As schematically shown in FIG. 4, the left reformer 18 </ b> L is accommodated in the left end portion of the first chamber 44. As shown in FIGS. 1 and 2, a pair of left and right manifolds 24L and 24R extend in the gap between the left cell stack 14L and the right cell stack 14R. More precisely, as shown in FIG. 4, a pair of left and right vertical manifolds 29L and 29R are arranged. The left reformer 18L and the left vertical manifold 29L are connected by a left reformed gas supply pipe 25L. Five left horizontal manifolds 24La, 24Lb, 24Lc, 24Ld, 24Le extend from the left vertical manifold. The horizontal manifold 24La distributes the reformed gas to the cell stack group 14La. The same applies to the subscripts b to e. In FIG. 4, only part of the cell stack group 14La is shown and others are omitted for clarity of illustration.
A right reformer 18R is accommodated at the right end of the first chamber. The right reformer 18R and the right vertical manifold 29R are connected by a right reformed gas supply pipe 25R. Five right horizontal manifolds 24Ra, 24Rb, 24Rc, 24Rd, and 24Re extend from the right vertical manifold 29R. The horizontal manifold 24Ra distributes the reformed gas to the cell stack group 14Ra. The same applies to the subscripts b to e. In FIG. 4, for the sake of clarity of illustration, the right horizontal manifold and the right cell stack group are not shown.
Below the right cell stack group 14R, a temperature-evaporating mixer 130 is arranged. The temperature rising evaporation mixer 130 is supplied with fuel gas from the fuel gas supply device 132 and water is supplied from the water supply device 134. The water supplied to the temperature rising evaporator 130 is evaporated to become water vapor and mixed with the fuel gas. The mixed gas of fuel gas and water vapor is preheated while passing through the temperature rising evaporating mixer 130. The preheated mixed gas is supplied from the left mixed gas supply pipe 27L to the left reformer 18L, and is supplied from the right mixed gas supply pipe 27R to the right reformer 18L. The temperature rising evaporator 130 is accommodated in the second chamber 46 through which the high-temperature exhaust gas passes (see FIG. 1).

The reformed gas reformed by the left reformer 18L is fed from the right end of the left cell stack 14L. At the left end of each left cell stack 14L, the reformed gas passage 20 is opened, and the reformed gas (off gas) that has not been consumed for power generation is released. The off-gas discharged from the left end of each cell stack 14L burns there. A combustor 17L is provided at each left end of the left cell stack 14L. The left combustor group 17L faces the surface 18Ls of the left reformer 18L.
The reformed gas reformed by the right reformer 18R is fed from the left end of the right cell stack 14R. At the right end of each cell stack 14R on the right side, the reformed gas passage 20 is opened, and the reformed gas (off gas) that has not been consumed for power generation is released. The off-gas released from the right end of each cell stack 14R burns there. A combustor 17R is provided at each right end of the right cell stack 14R. The left combustor group 17R faces the surface 18Rs of the right reformer 18R.

The pair of reformers 18L and 18R basically have the same configuration. Subscripts L and R will be omitted for common explanation. In the reformer 18, slit-like combustion gas passages 80a, 80b, 80c, and 80d extending in the vertical direction are formed in a flat box-shaped casing made of metal. As shown well in FIG. 4, an upper pipe 18m extending horizontally at a high position (in FIG. 4, it is indicated by 18Rm to indicate left and right, the same applies hereinafter) and a lower pipe extending horizontally at a lower position. The pipe 18n is composed of a plurality of vertical pipes 18a, 18b, 18c, 18d, and 18e communicating with both pipes 18m and 18n. The reformer 18 has a flat box shape as a whole, and combustion gas paths 80a, 80b, 80c, and 80d that penetrate from the flat surface 18s to the flat back surface 18t are formed.
Inside the reformer 18, a path for diverting to the vertical pipes 18a, 18b, 18c, 18d, and 18e is formed, and the reforming catalyst is filled in the path. The mixed gas of fuel gas and water vapor sent out from the temperature rising evaporator 130 enters the lower pipe 18n, enters the upper pipe 18m via any of the vertical pipes 18a, 18b, 18c, 18d, and 18e, and the process The reformed gas is made of hydrogen and carbon monoxide. The reformed reformed gas is sent from the reformed gas supply pipe 25 to the reformed gas passage 20 of the cell stack group 14 through the manifold 24. The pair of reformers 18L and 18R are connected by an upper crossover pipe 28, and the crossover pipe 28 ensures a balance between the left and right outlet pressures.

As shown in FIGS. 1 to 3, there are five air supply members 16 (upper and lower for the cell stack group 14 on the left side and five on the right side and up and down. The subscripts L and R indicating left and right and the subscripts a to e indicating the number of steps may be omitted) are shallow box-shaped members, and a plurality of air supply ports 16f are formed on the upper surface. . The air supply members 16a, 16b, 16c, 16d, and 16e are disposed below the cell stack groups 14a, 14b, 14c, 14d, and 14e, respectively. A baffle plate 52a extending substantially horizontally is formed on the side surface of the air supply member 16 on the manifold 24 side. The baffle plate 52a is mounted horizontally toward the upstream side (manifold side) of the upper cell stack 14, and connects the left and right air supply members 16. A baffle plate 52b extending substantially horizontally is formed on the side surface of the air supply member 16 on the reformer 18 side. The baffle plate 52b is attached toward the downstream side (reformer side) of the upper cell stack 14, and extends to the vicinity of the reformer 18. Both ends of each air supply member 16 communicate with the air supply pipes 50a and 50b as shown in FIGS. The air supply pipe 50 is made of metal and extends in the vertical direction as shown in FIGS. 1 and 3, and the upper end opens into the third chamber 48. The lower part of the third chamber 48 communicates with the air introduction pipe 34, and the air introduced from the outside by the air introduction pipe 34 passes through the third chamber 48 and is one of the pair of air supply pipes 50 a and 50 b. The air is supplied to the cell stacks 14a, 14b, 14c, 14d, and 14e at the uppermost part from the upper surface of any one of the upper and lower five-stage air supply members 16a, 16b, 16c, 16d, and 16e.
The upper and lower five-stage air supply members 16 are supported at both ends by air supply pipes 50a and 50b, and have high strength.
As shown in FIG. 2, each cell stack 14 extends in the left-right direction, and the air supply member 16 extends in the illustrated vertical direction. Both the cantilevered air supply members 16 and the cantilevered cell stack group 14 are in a positional relationship.
The cantilevered cell stack group 14 is mounted on the both-sided air supply member 16 via a packing, and the cantilevered cell stack 14 is stably supported in a horizontally extending posture. Yes. The cantilever cell stack 14 does not inadvertently tilt.

Fins 54 shown in FIG. 2 are attached to four outer peripheral surfaces of the outer partition wall 38 that partitions the third chamber 48 and the second chamber 46. The fins 54 are formed by folding a long metal plate member in a lateral direction into a substantially bellows shape. The outer side is in contact with the inner surface of the outer wall 40, and the inner side is in contact with the outer surface of the outer partition wall 38 (in FIGS. 1 to 3, the fin 54 and the wall surface are shown apart from each other in order to clarify the shape of the fin 54. ) In addition, in order to prevent heat dissipation, the structure which the inner surface of the fin 54 and the outer wall 40 contacts via a heat insulating material may be sufficient. As shown in FIGS. 1 and 3, a plurality of fins 54 are vertically attached to the four outer peripheral surfaces of the outer partition wall 38 to cover the outer peripheral surface. Although not shown, the upper and lower fins 54 are attached with a pitch shifted by half. Since the fins 54 are attached in this way, the outer partition wall 38, the fins 54, and the outer wall 40 extend vertically between the four outer peripheral surfaces of the outer partition wall 38 and the inner surface of the outer wall 40. A plurality of elongated prismatic passages are formed.
As shown in FIG. 2, the fins 56 are attached to the four inner peripheral surfaces of the outer partition wall 38 in the same manner as the fins 54. The shape of the fin 56 is the same as that of the fin 54. Since the fins 56 are attached in this manner, the outer partition wall 38, the fins 56, and the inner partition wall 36 span the entire area between the four inner peripheral surfaces of the outer partition wall 38 and the outer surface of the inner partition wall 36. Thus, a plurality of thin prismatic passages extending in the vertical direction (the direction perpendicular to the plane of FIG. 2) are formed. The fins 54 define the size of the third chamber 48, and the fins 56 define the size of the second chamber 46.

As shown in FIGS. 1 and 3, the outer partition wall 38 is fixed to the bottom plate 40 b of the outer wall 40 by a fixing wall 38 a that extends downward from the bottom plate 46 b of the second chamber 46. A plurality of holes 38b are formed in the fixing wall 38a so that air can freely flow. The inner partition wall 36 is also lifted from the bottom plate 46b of the second chamber 46 by a fixing wall 36a extending downward from the lower end of the bottom plate 44b of the first chamber. The bottom plate 44 b of the first chamber 44 is lifted from the bottom plate 46 b of the second chamber 46. A plurality of holes 36b are also formed in the fixing wall 36a so that the exhaust gas can freely flow. A gap between the bottom plate 44 b of the first chamber 44 and the bottom plate 46 b of the second chamber 46 constitutes a part of the second chamber 46. In the gap between the bottom plate 44b of the first chamber 44 and the bottom plate 46b of the second chamber 46 (a part of the second chamber 46), a temperature rising evaporator mixer 130 is disposed. The temperature rising evaporation mixer 130 is supplied with fuel gas from the fuel gas supply device 132 and water is supplied from the reforming water supply device 134. The temperature rising evaporator 130 is heated by the high-temperature exhaust gas, and mixes and heats the fuel gas and water vapor. The heated mixed gas is supplied from the mixed gas supply pipe 27 to the reformer 18. Between the bottom plate 44b of the first chamber 44 and the bottom plate 46b of the second chamber 46 is a part of the second chamber 46, and an exhaust passage 58 communicates therewith.
Between the bottom plate 40b of the outer wall 40 and the bottom plate 46b of the second chamber 46 is a part of the third chamber 48, and the air introduction pipe 34 communicates therewith. A third chamber 48 is located below the temperature rising evaporator 130.

The third chamber 48 surrounds the second chamber 46 on the six surfaces (four side surfaces, top surface, and bottom surface) of the power generation unit 10, and the second chamber 46 includes six surfaces (four side surfaces, top surface, and bottom surface) of the power generation unit 10. ) Surrounds the first chamber 44.
Air taken from outside passes through the third chamber 48. The exhaust gas generated in the first chamber 44 passes through the second chamber 46. The first chamber 44 is used as a storage chamber for the fuel cell group 14 and the reformer 18.
The first chamber 44 has the highest temperature, the second chamber 46 has the second highest temperature, and the third chamber 48 has the third highest temperature. The highest temperature first chamber 44 is surrounded by the second highest temperature second chamber 46, and the outside is surrounded by the third highest temperature third chamber 48. By arranging the first chamber 44 that needs to be maintained at the highest temperature on the innermost side, the first chamber 44 that accommodates the cell stack group 14 and the reformer 18 is easily maintained at the highest temperature. Yes.

The operation in the power generation unit 10 will be described. The common phenomenon will be described by omitting the subscripts L and R indicating left and right and the subscripts a to e indicating the number of stages.
The water fed from the water supply device 134 is preheated in the temperature rising evaporation mixer 130 and becomes steam. The fuel gas and water vapor sent from the fuel gas supply device 132 are mixed and preheated in the temperature rising evaporator mixer 130 and sent to the reformer 18 from the mixed gas supply pipe 27. The mixed gas sent to the reformer 18 is reformed into a reformed gas containing hydrogen and carbon monoxide in the reformer 18, and from each manifold 24 to the reformed gas passage 20 of each cell stack 14. Sent.
The air sent from the air introduction pipe 34 is sent to the third chamber 48, passes through the fins 54, reaches the upper portion, flows below the upper surface of the outer wall 40, and then opens to the third chamber 48. Flows into the air supply pipes 50a and 50b. During this time, the air is preheated by the hot exhaust gas. The preheated air that has flowed into the air supply pipe 50 moves downward and is sent to one of the air supply members 16a, 16b, 16c, 16d, and 16e. The air sent to the air supply member 16 is blown from the air supply port 16f on the upper surface to the outer peripheral surfaces of the cell stacks 14a, 14b, 14c, 14d, and 14e in the immediate upper part.
The air flowing out from the air supply port 16f rises upward or obliquely upward and is distributed over the entire lower side of the cell stack 14 immediately above. Oxygen ionizes, passes through the solid electrolyte, reaches the fuel electrode, reacts with hydrogen or carbon monoxide, and generates a potential difference between the oxygen electrode and the fuel electrode. That is, it generates electricity.

When, for example, 80% of the reformed gas supplied to the cell stack 14 is used for power generation, 20% of the reformed gas (off-gas) that has not been used for power generation passes through the reformed gas passage 20 from the tip. leak. Further, when, for example, 20% of the air supplied to the cell stack 14 is used for power generation, 80% of the air that is not used for power generation passes through the gap of the current collecting member 22 of the cell stack 14. This air is guided along the baffle plate 52b to the tip side of the cell stack 14.
A spark electrode is disposed near the tip of each cell stack 14. As the spark electrode sparks, the off-gas flowing out from the tip of each cell stack 14 is burned by the air induced to the tip side of each cell stack 14.
A combustor 17 is formed at the tip of each cell stack 14. 35 combustor groups 17L are formed corresponding to the 35 left cell stacks 14, and 35 combustor groups 17R are formed corresponding to the 35 right cell stacks 14. The 35 combustor groups 17L are located in substantially the same plane, and the plane and the surface 18Ls of the reformer 18L are close to each other and parallel to each other. The 35 combustor groups 17R are located in substantially the same plane, and the plane and the surface 18Rs of the reformer 18R are close to each other and parallel to each other. Since the combustor group 17 and the reformer 18 are close to each other, the endotherm accompanying the reforming reaction can be efficiently compensated by the combustion heat of the off gas.

The combustion gas obtained by burning off-gas in the combustor 17 heats the reformer 18. In this embodiment, since the reformer 18 is provided with the slit-like combustion gas passage 80, the combustion gas also enters the back surface 18t side of the reformer 18, and is heated from both the front surface 18s and the back surface 18t. The combustion gas passing through the front and back of the reformer 18 warms the reformer 18 uniformly, and the temperature unevenness in the reformer 18 can be suppressed.
As clearly shown in FIG. 2, the combustor 17a directly heats the surface of the vertical tube 18a. The combustors 17b and 17c exclusively heat the side surface of the vertical tube 18b. The combustor 17d directly heats the surface of the vertical tube 18c. The combustors 17e and 17f exclusively heat the side surface of the vertical tube 18d. The combustor 17g directly heats the surface of the vertical tube 18e. That is, the surface of the vertical tube 18a is directly heated, the vertical tube 18b is heated from the side, the surface of the vertical tube 18c is directly heated, the vertical tube 18d is heated from the side, and the surface of the vertical tube 18e is directly heated. . If the vertical tubes that directly heat the surface and the vertical tubes that heat the side surfaces are alternately arranged, a balance between the combustion gas flowing on the front surface side of the reformer 18 and the combustion gas flowing on the rear surface side of the reformer 18 is secured. The temperatures on the front and back sides of the reformer 18 are homogenized.

  The combustion gas is extremely hot and is difficult to put into the heat exchanger as it is. The material of heat exchangers that can withstand such high temperatures is limited and expensive. In this embodiment, the reformer 18 is first heated with combustion heat. The reforming reaction is an endothermic reaction, and the heat of combustion is used to compensate for the endotherm accompanying the reforming reaction. In order to compensate the endothermic reaction of the reforming reaction with the combustion heat, the temperature of the combustion gas decreases. The temperature of the combustion gas flowing through the second chamber 46 is appropriately cooled, and it is not necessary to use a special material for the partition walls 36 and 38.

The environmental temperature at which the electrochemical reaction of the fuel cell 12 proceeds efficiently is a high temperature of about 800 ° C. If this environmental temperature decreases, the power generation efficiency decreases. Accordingly, it is necessary to preheat the air supplied to the cell stack group 14 so that an environmental temperature of about 800 ° C. can be obtained.
The exhaust gas rising in the first chamber 44 flows along the upper surface of the first chamber 44 and flows into the second chamber 46. The exhaust gas flowing into the second chamber 46 passes through a plurality of thin prismatic passages extending in the vertical direction downward, flows into the lower portion of the second chamber 46, and is led out from the exhaust gas passage 58 to the outside. .
At this time, the air introduced from the air introduction pipe 34 flows into the third chamber 48 and passes upward through a plurality of thin prismatic passages extending in the vertical direction. Heat exchange is performed between the exhaust gas passing through the second chamber 46 and the air passing through the third chamber 48. The heat exchange rate is further increased by the fins 54 and 56 attached to both surfaces of the outer partition plate 38. The air supplied to the cell stack group 14 can be preheated to about 650 ° C. by this heat exchange. Since the air preheated to about 650 ° C. can be supplied to the cell stack group 14, the cell stack group 14 can be maintained at an appropriate power generation temperature.
The exhaust gas is cooled by preheating the air. The exhaust gas passing through the temperature-evaporating mixer 130 is slightly less than 400 ° C. The exhaust gas at this temperature is sufficient to preheat the mixed gas of fuel gas and water vapor and is not so hot as to deposit carbon from the fuel gas. By supplying the preheated mixed gas to the reformer 18, burning off-gas in the vicinity of the reformer 18, and forming the combustion gas passage 80 in the reformer 18, the rear surface of the reformer 18 is also formed. By surrounding the combustion gas, the entire reformer 18 can be maintained at an appropriate reforming temperature.
The power generation unit of the present embodiment can be heat independent.

  In this embodiment, baffle plates 52a are arranged between the left and right air supply members 16L and 16R, and the left and right air supply members 16L and 16R are connected, and the generated heat generated in the lower cell stack is in the upper stage. It is not transmitted to the cell stack. The baffle plate 52b extends close to the reformer 18 so that the combustion gas does not flow upward as it is. By extending the baffle plate 52 b to the vicinity of the reformer 18, it contributes to turning the combustion gas to the back side of the reformer 18.

  In the present embodiment, the first chamber 44 is surrounded by the second chamber 46 having the second highest temperature and the third chamber 48 having the third highest temperature is surrounded by the second chamber 46. It is easy to maintain 44 at high temperature. Therefore, the temperature in the first chamber 44 that accommodates the fuel cell group 14 and the reformer 18 is only set to 800 to 850 ° C., which is the optimum temperature for power generation, by only the heat generated with power generation and the combustion heat of off-gas. Can be maintained. Can heat independent.

As mentioned above, although embodiment of this invention was described in detail, these are only illustrations and do not limit a claim. The technology described in the claims includes various modifications and changes of the specific examples illustrated above.
For example, the vertical pipes 18a to 18e of the reformer 18 can be formed of a pipe material different from the upper pipe 18m and the lower pipe 18n. If the pipe material is provided with a gap, the combustion gas passage can be secured by the gap.
The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. The technology illustrated in this specification or the drawings achieves a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

The figure which shows the longitudinal cross-section of the electric power generation unit 10. FIG. The figure which shows the cross section of the electric power generation unit. The figure which shows another vertical cross section of the electric power generation unit. The figure which shows the piping system in the 1st chamber 44 typically. The figure which shows the cross section of the fuel battery cell 12 typically.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Power generation unit 12 ... Fuel cell 12a ... Fuel electrode 12b ... Solid electrolyte layer 12c ... Oxygen electrode 12d ... Interconnector 14 ... Cell stack or cell stack Group 16 ... Air supply member 18 ... Reformer 20 ... Reformed gas passage 22 ... Current collecting member 24 ... Manifold 25 ... Reformed gas supply pipe 27 ... Mixed gas supply pipe 29 ... Vertical manifold 34 ... Air inlet pipe 36 ... Inner partition wall 38 ... Outer partition wall 40 ... Outer wall 42 ...・ Heat insulation member 44 ・ ・ ・ ・ first chamber 46 ・ ・ ・ ・ second chamber 48 ・ ・ ・ ・ third chamber 50 ・ ・ ・ ・ air supply pipe 52 a ・ baffle plate 52 b ・ baffle plates 54 and 56・ Fin 58... Exhaust gas passage 80... Combustion gas passage 130. Engager 132 ... fuel gas supply device 134 ... Water supply

Claims (2)

A power generation device using a solid oxide fuel cell;
It has a reformer and multiple cell stacks.
A plurality of cell stacks are arranged substantially parallel to each other at intervals so that the off-gas combustor group formed at the tip of each cell stack is located in substantially the same plane,
The reformer is disposed substantially parallel to the plane on which the off-gas combustor group is located,
The reformer is formed with a combustion gas passage penetrating from the surface facing the off-gas combustor group to the opposite surface .
Each cell stack is arranged to extend horizontally,
A plurality of cell stacks are arranged in a matrix at intervals in the horizontal direction and the vertical direction,
The reformer is formed with a combustion gas passage extending in a vertical direction . The reformer has a flat box shape;
The power generator according to claim 1, wherein the combustion gas passage is formed so as to penetrate from a flat surface of the reformer to a flat back surface.

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