JP7263190B2 - fuel cell system - Google Patents

Description

The present invention relates to fuel cell systems.

A solid oxide fuel cell needs to be heated to an operating temperature of over 700° C. during start-up. Conventionally, an air preheater (electrical air heater) is provided as a means for raising the temperature at the start of a solid oxide fuel cell. A fuel cell system that raises temperature has been proposed (see, for example, Patent Document 1).

JP-A-2004-119299

In the system of Patent Literature 1 described above, the temperature of the air can be raised in a short period of time by increasing the output of the air preheater when starting the solid oxide fuel cell. If an attempt is made to achieve such a high output with a single air preheating heater, the outer dimensions of the heater main body become large. In order to avoid an increase in the outer dimensions of the heater main body, it is conceivable to provide a plurality of low-output air preheating heaters and arrange them in series to increase the output of the air preheating heaters. Also, when air preheaters are arranged in series and air is circulated, it is required to properly insulate the air preheaters without generating local high temperature areas.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems. To provide a fuel cell system capable of appropriately insulating the

A fuel cell system according to one aspect of the present invention includes a solid oxide fuel cell, a fuel supply line for supplying fuel gas to the solid oxide fuel cell, and air for supplying air to the solid oxide fuel cell. a plurality of air preheating heaters provided in the air supply line for heating the air when the solid oxide fuel cell is started; and a plurality of air preheating heaters provided in the air supply line for insulating the air preheating heaters. wherein the plurality of air preheaters are arranged in series in the air supply line, and a pair of adjacent insulation members among the plurality of insulation members sandwich the air preheater. Each insulating member is composed of a porous member having a plurality of holes arranged in a flow direction of the air flowing through the air supply line.

ADVANTAGE OF THE INVENTION According to this invention, when arrange|positioning several air preheating heaters in series, an air preheating heater can be insulated appropriately, without generating a local high temperature part.

1 is a conceptual diagram of a fuel cell system according to an embodiment; FIG. 3 is a perspective view showing part of an air supply line of the fuel cell system according to this embodiment; FIG. FIG. 4 is a cross-sectional view around an air preheater housed in the air supply line according to the present embodiment; FIG. 3 is a schematic diagram around an air preheater housed in an air supply line according to the present embodiment; FIG. 4 is a schematic diagram of an insulating member used together with the air preheater according to the present embodiment;

Hereinafter, fuel cell systems according to embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the present invention is not limited to the following embodiments, and can be modified in various ways within the spirit and scope of the invention.

FIG. 1 is a conceptual diagram of a fuel cell system 1 according to this embodiment. As shown in FIG. 1, the fuel cell system 1 includes a solid oxide fuel cell (hereinafter referred to as "SOFC") 2, a fuel supply line L1 for supplying fuel gas to the SOFC 2, and and an air supply line L2 for supplying air.

SOFC2 has a power generation mechanism in which oxide ions generated at the air electrode permeate the electrolyte and move to the fuel electrode, where the oxide ions react with hydrogen or carbon monoxide to generate electrical energy. .

The flow rate of the fuel gas supplied from the fuel supply line L1 to the SOFC 2 is adjusted by a fuel supply blower, a mass flow controller, or the like (not shown). For example, fuel gas is composed of city gas. The fuel gas that has reacted within the SOFC 2 is exhausted through the exhaust line L3. Air supplied to the SOFC 2 from the air supply line L2 is adjusted in flow rate by the air supply blower 3 . Air that has reacted within the SOFC 2 is exhausted through an exhaust line L4.

The air supply line L2 has a first air supply line L21 and a second air supply line L22 branched from the first air supply line L21. The first air supply line L21 is attached with an air preheating heater 4 that is mainly used at startup. Air preheater 4 is preferably an electric heater. The air preheating heater 4 is divided into a plurality of (three in the present embodiment) air preheating heaters 4 (4a, 4b, 4c). For convenience of explanation, these air preheating heaters 4a, 4b and 4c are hereinafter referred to as heater elements 4a, 4b and 4c, respectively. These heater elements 4a, 4b, 4c are individually activatably controlled. That is, each heater element can be individually controlled ON/OFF.

Although not limited, the output of the air preheater 4 is 1/5 to 2/3 of the SOFC 2 rated output. Assuming that the output of the air preheating heater 4 is x kW, the sum of the outputs of the heater elements 4a, 4b and 4c is adjusted to x kW. For example, the power of the first heater element 4a is x/6 kW, the power of the second heater element 4b is x/3 kW and the power of the third heater element 4c is x/2 kW. By way of example, the total power of the air preheating heater 4 is 24 kW, the power of the first heater element 4a is 4 kW, the power of the second heater element 4b is 8 kW, the power of the third heater The output of element 4c is 12 kW. Although the air preheating heater 4 is divided into three parts in FIG. 1, it may be divided into two parts or four parts or more.

A regenerative heat exchanger 5 is attached to the second air supply line L22. The regenerative heat exchanger 5 is connected between the exhaust line L4 and the second air supply line L22. When the SOFC 2 is in operation, the regenerative heat exchanger 5 performs heat exchange between the post-reaction air (oxidant off-gas) flowing through the exhaust line L4 and the air flowing through the second air supply line L22. . Thereby, the air flowing through the second air supply line L22 is warmed and supplied to the SOFC2.

A first valve 6 is provided between the air supply blower 3 and the air preheater 4 in the first air supply line L21. A second valve 7 is provided between the air supply blower 3 and the regenerative heat exchanger 5 in the second air supply line L22. These first and second valves 6 and 7 are used when switching the supply route of air supplied to the SOFC 2 .

A first temperature-measuring thermocouple 8 is provided on the outlet side of the air preheater 4 in the air supply line L2 (first air supply line L21). A first temperature measuring thermocouple 8 measures the temperature of the air heated by the air preheater 4 . A second temperature-measuring thermocouple 9 is connected to the SOFC 2 . A second temperature-measuring thermocouple 9 measures the temperature inside the SOFC 2 . The temperatures measured by these first and second temperature-measuring thermocouples 8 and 9 are output to a control unit (not shown) that controls the fuel cell system 1 to control the fuel cell system 1 (for example, the 1, switching control of the second valves 6 and 7, driving control of the air preheating heater 4, etc.).

A fuel recirculation line L5 is provided between the fuel supply line L1 and the exhaust line L3. A recirculation blower 10 is provided in the fuel recirculation line L5. The recirculation blower 10 sends the reacted fuel gas (fuel off-gas) flowing through the exhaust line L3 to the fuel supply line L1. By feeding the fuel off-gas into the fuel supply line L1, the fuel gas is reformed by water vapor contained in the fuel off-gas.

In the fuel cell system 1 having such a configuration, when the SOFC 2 is started, the second valve 7 is closed, the first valve 6 is opened, and the heater elements 4a, 4b, 4c are appropriately selected and turned on. to stepwise increase the temperature of the air supplied to the SOFC 2. By gradually increasing the temperature of the air supplied to the SOFC 2 in this manner, the temperature of the SOFC 2 can be raised to the operating temperature while preventing damage to the SOFC 2 due to a sudden temperature rise.

After the SOFC 2 has risen to an operating temperature capable of generating electricity, the first valve 6 is closed and the second valve 7 is opened. Air is thereby supplied to the SOFC 2 from the second air supply line L22. In the SOFC 2, the electrochemical reaction between the fuel gas supplied from the fuel supply line L1 and the air (oxidant gas) supplied from the second air supply line L22 via the regenerative heat exchanger 5 causes power generation in the SOFC 2. is started.

Here, the configuration around the air preheater 4 included in the fuel cell system 1 according to the present embodiment will be described with reference to FIGS. 2 to 4. FIG. FIG. 2 is a perspective view showing part of the air supply line L2 of the fuel cell system 1 according to this embodiment. FIG. 2 shows piping arranged between the first valve 6 and the first thermocouple 8 for temperature measurement in the air supply line L2. FIG. 3 is a sectional view around the air preheater 4 housed in the air supply line L2. FIG. 4 is a schematic diagram around the air preheating heater 4 housed in the air supply line L2.

As shown in FIG. 2, the air supply line L2 is arranged downstream of the first pipe 11 downstream of the first valve 6 and upstream of the first thermocouple 8 for temperature measurement. 11 and a second pipe 12 connected to the latter stage of the pipe 11 . For example, the first pipe 11 and the second pipe 12 are made of stainless steel, but are not limited to this.

In the piping shown in FIG. 2 , air flows in from the inlet opening 11 A of the first piping 11 , travels through the first piping 11 and the second piping 12 , and flows out from the outlet opening 12 A of the second piping 12 . A pipe (not shown) on the upstream side of the first pipe 11 is connected by a flange portion 11B around the inlet opening 11A. Also, the first pipe 11 and the second pipe 12 are connected by joining the respective flange portions 11C and 12B. On the other hand, a pipe (not shown) on the downstream side of the second pipe 12 is connected by a flange portion 12C around the outlet opening 12A.

A power connection work pipe 13 is provided in the first pipe 11 . As will be described later, the power supply connection work pipe 13 is a pipe for the work of connecting the power supply to the air preheating heater 4 (more specifically, the heater elements 4a, 4b, 4c) housed in the second pipe 12. is. A worker who stores the air preheating heater 4 in the second pipe 12 connects the power supply cable to the air preheating heater 4 through the power connection work pipe 13 . The power connection work pipe 13 is closed by the lid portion 13A after the end of the work.

The second pipe 12 has a generally cylindrical shape. As shown in FIG. 3, the second pipe 12 houses the air preheating heater 4 (heater elements 4a, 4b, 4c). Although not limited, the heater elements 4a, 4b, and 4c are composed of resistance heating heaters in which a long thin metal plate having minute unevenness on the plate surface is spirally overlapped. be. Heater elements 4a, 4b, and 4c each have a disk-shaped external shape by spirally overlapping thin metal plates (see FIG. 4). The dimensions of the outer shape of the heater elements 4 a , 4 b , 4 c are slightly smaller than the inner peripheral surface of the second pipe 12 . Further, since the thin metal plate has an uneven shape, the heater elements 4a, 4b, and 4c have a large number of holes in the direction of air flow in the second air supply line L21.

The heater elements 4a, 4b, 4c are arranged side by side from the upstream side (right side shown in FIG. 3) to the downstream side (left side shown in FIG. 3) along the air flow direction in the air supply line L2. there is Thermocouple insertion portions 12D are provided on the upper portion of the second pipe 12 corresponding to the positions of these heater elements 4a, 4b, and 4c (see FIGS. 2 and 3). A thermocouple for temperature measurement (not shown) for measuring the temperature of the heater elements 4a, 4b, and 4c is inserted into the thermocouple insertion portion 12D. The temperature-measuring thermocouples are used to detect excessive temperature increases in the heater elements 4a, 4b, and 4c. In addition, in FIG. 1, the thermocouple for temperature measurement is omitted for convenience of explanation.

A plurality of insulating members 14 (14a to 14d) are arranged upstream and downstream of each heater element 4a, 4b, 4c (see FIGS. 3 and 4). A pair of adjacent insulating members 14 among the plurality of insulating members 14 (14a to 14d) are arranged with the heater elements 4a, 4b, 4c sandwiched therebetween. The heater element 4a is arranged in a state sandwiched between an insulating member 14a arranged on the upstream side and an insulating member 14b arranged on the downstream side. Similarly, the heater element 4b is sandwiched between insulating members 14b and 14c, and the heater element 4c is sandwiched between insulating members 14c and 14d.

The insulating member 14 has a generally disk-shaped outer shape (see FIG. 4). The insulating member 14 is arranged coaxially with the heater elements 4a, 4b, 4c. The dimensions of the outer shape of the insulating member 14 are slightly larger than the dimensions of the outer shape of the heater elements 4 a , 4 b , 4 c and slightly smaller than the inner peripheral surface of the second pipe 12 . The dimensions of the outer shape of the insulating member 14 may be the same as the dimensions of the outer shape of the heater elements 4a, 4b, and 4c.

The insulating member 14 is arranged in close contact with the side surfaces of the adjacent heater elements 4a, 4b, and 4c (the upstream side surface or the downstream side surface in the air flow direction). For example, the insulating member 14b is arranged in close contact with the downstream side surface of the heater element 4a arranged on the upstream side, and is arranged in close contact with the upstream side surface of the heater element 4b arranged on the downstream side. . The same applies to the other insulating members 14a, 14c and 14d.

As described above, the dimension of the outer shape of the insulating member 14 is slightly larger than the dimension of the outer shape of the heater elements 4a, 4b, 4c. For this reason, the insulating member 14 is arranged so as to face the entire side surface (upstream side surface or downstream side surface in the air flow direction) of the adjacent heater elements 4a, 4b, and 4c. For example, the insulating member 14b is arranged to face the entire downstream side surface of the heater element 4a arranged on the upstream side, while the insulating member 14b is arranged to face the entire upstream side surface of the heater element 4b arranged on the downstream side. ing. The same applies to the other insulating members 14a, 14c and 14d.

A certain gap G is formed between the outer circumferences of the heater elements 4a, 4b, 4c and the insulating members 14a to 14d sandwiching them (see FIG. 3). An insulating material (not shown) is inserted into the gap G. For example, the insulating material may consist of blanket-like insulation. By using a blanket-like heat insulating material, in addition to ensuring insulation between the heater elements 4a, 4b, 4c and the pipes, it is also possible to prevent the air warmed by the heater elements 4a, 4b, 4c from radiating from the pipes. to heat the air. In addition, the gap G is formed by a pair of cables connected to the power supply connection cables of the heater elements 4a, 4b, and 4c (more specifically, the outermost and innermost peripheral portions of the thin metal plates constituting the heater elements 4a, 4b, and 4c). It is also used as a space to lead out the power supply connection cable).

A stopper 12E is provided on the downstream side of the insulating member 14d arranged on the most downstream side. A stopper 12F is provided on the upstream side of the insulating member 14a arranged on the most upstream side. These stoppers 12E and 12F are joined to the inner peripheral surface of the second pipe 12 by welding or the like. These stoppers 12E and 12F are used for positioning the insulating members 14d and 14a. By positioning the insulating members 14d and 14a with these stoppers 12E and 12F, a unit (hereinafter referred to as an "air preheating heater unit") consisting of the heater elements 4a to 4c and the insulating members 14a to 14d is positioned.

When housing the air preheating heater unit in the second pipe 12, the insulating member 14d is housed in the second pipe 12 so that the outer edge of the side surface (downstream side) of the insulating member 14d contacts the stopper 12E. Then, the heater element 4c is housed in the second pipe 12 so that the side surface (downstream side surface) of the heater element 4c contacts the side surface (upstream side surface) of the insulating member 14d. Next, the insulating member 14c is accommodated in the second pipe 12 so that the side surface (downstream side surface) of the insulating member 14c contacts the side surface (upstream side surface) of the heater element 4c. Thereafter, similarly to the heater element 4c and the insulating member 14c, the heater element 4b, the insulating member 14b, the heater element 4a and the insulating member 14a are accommodated in the second pipe 12 in this order. Finally, after the stopper 12F is placed in contact with the outer edge of the side surface (upstream side surface) of the insulating member 14a, the stopper 12F is welded to the inner peripheral surface of the second pipe 12. As shown in FIG. As a result, the air preheater unit is sandwiched between the pair of stoppers 12E and 12F.

Here, the configuration of the insulating member 14 used together with the air preheating heater 4 (heater elements 4a, 4b, 4c) according to the present embodiment will be described. FIG. 5 is a schematic diagram of the insulating member 14 used together with the air preheating heater 4 (heater elements 4a, 4b, 4c) according to this embodiment. Since the insulating members 14a to 14d have a common configuration, they will be referred to as the insulating member 14 unless otherwise specified.

As shown in FIG. 5, the insulating member 14 has a generally disk shape. Without limitation, the insulating member 14 is constructed of a ceramic material. For example, the insulating member 14 is composed of a porous member having a plurality of holes (openings) arranged in the flow direction of the air flowing through the air supply line L2. In the present embodiment, the insulating member 14 is formed with a plurality of holes (openings) 141 arranged in parallel with the axial direction of the insulating member 14 . Each hole 141 has a regular hexagonal shape, except for those located at the outer edge of the insulating member 14 . The insulating member 14 has a honeycomb structure in which these holes 141 are arranged without gaps. That is, holes 141 having the same opening area are formed through the insulating member 14 except for the outer edge.

Although not shown, the insulating member 14 is partially formed with a notch or groove through which a power supply cable connected to the adjacent air preheating heater 4 (heater elements 4a, 4b, 4c) passes. It is The power supply cable is guided through this notch or groove to the gap G on the outer peripheral side of the air preheating heater unit, and through this gap G to the power connection work pipe 13 .

Hereinafter, the mode of air flowing through the first air supply line L21 when the fuel cell system 1 is started will be described with reference to FIGS. 1 to 3. FIG. Here, it is assumed that all the heater elements 4a, 4b, 4c constituting the air preheating heater 4 are switched to the ON state.

The air sent into the first air supply line L21 by the air supply blower 3 flows through the first pipe 11 into the second pipe 12 (see FIGS. 1 and 2). The air that has flowed into the second pipe 12 flows into the hole 141 in the insulating member 14a arranged on the most upstream side among the insulating members 14 that constitute the air preheating heater unit. In the insulating member 14a, the holes 141 have the same opening area and are evenly arranged. Therefore, the air flows into the insulating member 14a in a uniformly rectified state.

The air rectified by the insulating member 14a flows into the heater element 4a. As described above, the heater element 4a has a large number of holes forming flow paths along the direction of air flow. Further, the heater element 4a is arranged in close contact with the insulating member 14a. Therefore, a large number of holes formed in the heater element 4a are arranged to communicate with some or all of the holes 141 of the insulating member 14a. Therefore, the air rectified by the insulating member 14a flows through the heater element 4a while maintaining the rectified state. In the process of passing through the holes 141 in the heater element 4a, the air is heated by the heat generated by the heater element 4a.

The air heated by the heater element 4a flows into the insulating member 14b arranged downstream of the heater element 4a. The insulating member 14b is arranged in close contact with the heater element 4a. Therefore, a large number of holes formed in the heater element 4a are arranged to communicate with some or all of the holes 141 of the insulating member 14b. Therefore, the air heated by the heater element 4a flows into the holes of the insulating member 14b and is further rectified.

Thereafter, similarly, the air rectified by the insulating member 14b flows through the heater element 4b while maintaining the rectified state. In the process of passing through the heater element 4b, the air is further heated by the heat generated by the heater element 4b and flows into the insulating member 14c. The air heated by the heater element 4b flows into the holes of the insulating member 14c and is further rectified. The air rectified by the insulating member 14c flows through the heater element 4c while maintaining the rectified state. In the process of passing through the heater element 4c, the air is further heated by the heat generated by the heater element 4c and flows into the insulating member 14d. The air heated by the heater element 4c flows into the holes of the insulating member 14d and is further rectified before flowing out of the air preheating heater unit. The air that has flowed out of the air preheating heater unit flows through the second pipe 12 and is supplied to the SOFC 2 through the outlet opening 12A.

As described above, in the fuel cell system 1 according to the present embodiment, a plurality of air preheating heaters 4 (heater elements 4a to 4c) are provided in the air supply line L2 and heat the air when the SOFC 2 is started, A plurality of insulating members 14 (14a to 14d) for insulating these air preheating heaters 4 are provided. A pair of adjacent insulating members (for example, insulating members 14a and 14b) among the plurality of insulating members 14 are arranged with the air preheater 4 (for example, heater element 4a) sandwiched therebetween, and each insulating member 14 is composed of a porous member in which a plurality of holes 141 are arranged in the flow direction of the air flowing through the air supply line L2 (see FIG. 4).

According to this configuration, the insulating member 14 for insulating the air preheating heater 4 is made of a porous member, and the air preheating heater 4 is sandwiched between the insulating members 14 made of the porous member. Since the air resistance can be made uniform by the insulating member 14 arranged in the air preheater 4, it is possible to suppress the situation where the air preheater 4 is locally heated. Moreover, since the air preheater 4 is sandwiched between the pair of insulating members 14, the adjacent air preheaters 4 can be prevented from coming into contact with each other, so that the air preheater 4 can be appropriately insulated. As a result, when a plurality of air preheating heaters 4 are arranged in series, the air preheating heaters 4 can be appropriately insulated without generating local high temperature portions in the air preheating heaters 4 . As a result, the air preheating heater 4 (heater elements 4a to 4c) can be prevented from being burnt out and the insulation resistance can be prevented from decreasing, and the reliability of the fuel cell system 1 as a whole can be improved.

In particular, in the fuel cell system 1 according to the present embodiment, the insulating member 14 is arranged in close contact with the side surfaces (upstream side surface and downstream side surface) of the adjacent air preheating heaters 4 . For example, the insulating member 14b is arranged in close contact with the downstream side surface of the air preheating heater 4a arranged on the upstream side, and is arranged in close contact with the upstream side surface of the air preheating heater 4b arranged in the downstream side. be. As a result, the air rectified by the plurality of holes 141 arranged in the insulating member 14 can be flowed into the air preheating heater 4 while maintaining the rectified state. can be heated to

Further, in the fuel cell system 1 according to the present embodiment, the insulating members 14 and the air preheating heaters 4 are alternately arranged along the flow direction of the air flowing through the air supply line L2. For example, in the air preheating heater unit described above, the insulating member 14a, the heater element 4a, the insulating member 14b, the heater element 4b, the insulating member 14c, the heater element 4c, the insulating member 14d and the insulating member 14 and the air preheating heater 4 are alternately arranged. are placed in As a result, the rectification of the air and the heating of the air can be continuously repeated, so that the air that has flowed into the air preheater 4 can be heated more efficiently.

Furthermore, in the fuel cell system 1 according to the present embodiment, the insulating member 14 is arranged so as to face the entire side surface of the adjacent air preheater 4 . For example, the insulating member 14b is arranged to face the entire downstream side (entire surface) of the air preheater 4a arranged on the upstream side. As a result, the air heated by the air preheater 4 can be prevented from leaking out of the insulating member 14, so that the entire flow of the air heated by the air preheater 4 can be rectified.

Furthermore, in the fuel cell system 1 according to the present embodiment, the insulating member 14 has a plurality of holes 141 each having a regular hexagonal shape, and has a honeycomb structure in which these holes 141 are arranged without gaps ( See Figure 5). Since the insulating member 14 has a honeycomb structure in this manner, the air flowing into the insulating member 14 can be effectively rectified. The temperature distribution within 4 can be reduced. Here, the plurality of holes 141 of the insulating member 14 may not have a regular hexagonal shape, and may have another shape such as a square, an equilateral triangle, a regular pentagon, or a combination of a regular pentagon and a regular hexagon.

Although the present embodiment has been described, another embodiment of the present invention may be a combination of the above embodiments and modifications in whole or in part. For example, in the fuel cell system 1 according to the above embodiment, a case is described in which a plurality of air preheating heaters 4 (heater elements 4a, 4b, 4c) are provided. can be Even when a single air preheater 4 is provided, the air preheater 4 is sandwiched between a pair of insulating members 14 (porous members) having the same configuration as in the above embodiment. In this case, since the air is rectified by the holes 141 (see FIG. 5) provided in the insulating member 14 sandwiching the air preheating heater 4, the air preheating heater 4 is locally heated. can be prevented. As a result, it is possible to prevent the air preheating heater 4 from being burnt out and improve the reliability of the fuel cell system 1 as a whole.

Moreover, the embodiments of the present invention are not limited to the above-described embodiments, and may be variously changed, replaced, and modified without departing from the spirit of the technical idea of the present invention. Furthermore, if the technical idea of the present invention can be realized in another way due to advances in technology or another derived technology, that method may be used. Therefore, the claims cover all embodiments that can be included within the scope of the technical concept of the present invention.

Characteristic points in the above embodiment are summarized below.
The fuel cell system described in the above embodiment includes a solid oxide fuel cell, a fuel supply line that supplies fuel gas to the solid oxide fuel cell, and air that supplies air to the solid oxide fuel cell. an air supply line, a plurality of air preheaters provided in the air supply line for heating the air when the solid oxide fuel cell is started, and an air preheater provided in the air supply line for insulating the air preheater. and a plurality of insulating members, wherein the plurality of air preheaters are arranged in series in the air supply line, and a pair of adjacent insulating members among the plurality of insulating members sandwich the air preheater. and each insulating member is composed of a porous member having a plurality of holes arranged in a flow direction of the air flowing through the air supply line.

Further, in the fuel cell system according to the above embodiment, the insulating member is arranged in close contact with the side surfaces of the adjacent air preheating heaters.

Furthermore, in the fuel cell system according to the above embodiment, the insulating members and the air preheating heaters are alternately arranged along the flow direction of the air flowing through the air supply line.

Furthermore, in the fuel cell system according to the above embodiment, the insulating member is arranged to face the entire side surface of the adjacent air preheater.

Furthermore, in the fuel cell system according to the above embodiment, the insulating member has a plurality of holes each having a regular hexagonal shape, and has a honeycomb structure in which the plurality of holes are arranged without gaps. do.

INDUSTRIAL APPLICABILITY As described above, the present invention has the effect of being able to properly insulate the air preheaters without generating local high temperature areas when a plurality of air preheaters are arranged in series. It is particularly useful for fuel cell systems with solid oxide fuel cell modules.

Reference Signs List 1: fuel cell system 3: air supply blower 4: air preheating heaters 4a to 4c: heater element 5: regenerative heat exchanger 6: first valve 7: second valve 8: first thermocouple 9 for temperature measurement : Second thermocouple for temperature measurement 10 : Recirculation blower 11 : First pipe 12 : Second pipe 12E, 12F : Stopper 13 : Power connection work pipe 14 : Insulating members 14a to 14d : Insulating member 141 : Hole G : Gap L1 : Fuel supply line L2 : Air supply line L21 : First air supply line L22 : Second air supply line L3 : Exhaust line L4 : Exhaust line L5 : Fuel recirculation line

Claims (5)

a solid oxide fuel cell;
a fuel supply line for supplying fuel gas to the solid oxide fuel cell;
an air supply line for supplying air to the solid oxide fuel cell;
a plurality of air preheating heaters provided in the air supply line for heating the air when the solid oxide fuel cell is started;
a plurality of insulating members provided in the air supply line and insulating the air preheater;
The plurality of air preheaters are arranged in series within the air supply line,
A pair of adjacent insulating members among the plurality of insulating members are arranged with the air preheater interposed therebetween, and each insulating member has a plurality of holes in a flow direction of the air flowing through the air supply line. A fuel cell system comprising an array of porous members. 2. The fuel cell system according to claim 1, wherein the insulating member is arranged in close contact with side surfaces of the adjacent air preheaters. 3. The fuel cell system according to claim 1, wherein the insulating members and the air preheaters are alternately arranged along the flow direction of the air flowing through the air supply line. 4. The fuel cell system according to any one of claims 1 to 3, wherein the insulating member is arranged to face the entire side surfaces of the adjacent air preheaters. 5. The insulating member according to any one of claims 1 to 4, wherein the insulating member has the plurality of holes each having a regular hexagonal shape, and has a honeycomb structure in which the plurality of holes are arranged without gaps. fuel cell system.

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