A solid oxide fuel cell system

Abstract

This invention discloses a solid oxide fuel cell system, including a burner, a heat exchanger, and multiple power generation stacks. The heat exchanger is a vertically arranged annular component, and the power generation stacks are solid oxide fuel cell stacks. The burner is located in the middle of the heat exchanger annulus. Multiple power generation stacks are spaced apart along the annulus between the burner and the heat exchanger. Each power generation stack has an air inlet, an air outlet, a fuel inlet, and a fuel outlet. The burner has an air inlet, a fuel inlet, and an exhaust gas outlet. Multiple air outlets are connected to the air inlet, and multiple fuel outlets are connected to the fuel inlet. The heat exchanger has at least three heat exchange channels, and the exhaust gas outlet, multiple air inlets, and multiple fuel inlets are each connected to at least one heat exchange channel. The heat exchanger is used to preheat the air and fuel separately using the waste heat of the exhaust gas. By arranging multiple power generation stacks between the heat exchanger and the burner, the internal and external parts of the power generation stacks can be heated synchronously with a small internal temperature difference.

Description

Technical Field

[0001] This invention belongs to the field of solid oxide fuel cell technology, and particularly relates to a solid oxide fuel cell system. Background Technology

[0002] Solid oxide fuel cells (SOFCs) offer advantages such as being all-solid-state, low-noise, and having a wide range of fuels. They directly convert the chemical energy of fuel into electrical energy through an electrochemical reaction, resulting in high efficiency and clean, pollution-free operation. SOFCs operate at temperatures between 500-800℃, and in practice, the fuel cell stack needs to be integrated with peripheral systems to form an independent power generation system. The peripheral systems mainly include an energy storage unit (providing power during startup), a control unit (controlling and providing feedback to various system components), a gas supply unit (blower, flow meter, shut-off valve, connecting pipes, etc.), and thermal components (combustion chamber, air heat exchanger, fuel heat exchanger, reformer), etc.

[0003] However, the following problems exist in the heating process of the power generation stack: the speed at which the heat carried by the preheated anode and cathode gases can heat the power generation stack to the working temperature is very slow, and the response time is long; in addition, since the ambient temperature around the stack is much lower than the core working temperature, a lot of heat will be lost during the heating process, which will also lead to the core heating being too slow.

[0004] In addition to the issues mentioned above, excessive temperature gradients in the internal hot zones of the fuel cell stack are also a significant reason for the inability to heat up rapidly. The temperature difference between the anode and cathode gases entering the fuel cell stack can create large local temperature gradients in both planar and vertical directions. Due to the multi-layered ceramic-metal composite structure of the stack, these large temperature gradients lead to regional stress concentrations within the stack. When these temperature gradients become too large, the stress concentration exceeds critical levels, causing component delamination and cracking, resulting in a sudden decline in stack performance or even failure, reducing the stack's stability and lifespan. Furthermore, heat exchange between the fuel cell stack and its surrounding environment can cause slow heating and difficulties in temperature control.

[0005] Current technical literature fails to simultaneously address the three crucial indicators of rapid heating and cooling, efficient heat exchange, and a small temperature gradient. For example, the scheme disclosed in document CN106784924 B, "A Thermal Zone Structure of a Solid Oxide Fuel Cell Power Generation System," accelerates the heating rate by directly introducing combustion exhaust gas, but it cannot control the temperature gradient during the heating process. Furthermore, activating the reformer and vaporizer during heating further exacerbates the temperature gradient between the center of the array and the cathode inlet region. Another example is document CN106784924 B... The solution disclosed in CN217822896U, "A Hot Zone Structure for a Solid Oxide Fuel Cell System," involves wrapping the fuel cell stack module with air intake and exhaust channels. Since the air outlet of the fuel cell stack is typically the hottest area, the adjacent air exhaust channels and burner further accumulate heat, increasing the temperature gradient of the stack. Similarly, the solution disclosed in patent CN119495764 B, "A Hot Zone Gas Processing Unit for a Solid Oxide Fuel Cell," features a compact thermal structure that, while improving the thermal efficiency of the equipment, still fails to solve the problem of slow hot-start of the fuel cell stack. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a solid oxide fuel cell system with a simple structure, efficient heat utilization, and the ability to simultaneously heat the fuel cell stack internally and externally to increase the heating rate and reduce the temperature difference.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A solid oxide fuel cell system includes a burner, a heat exchanger, and multiple power generation stacks. The heat exchanger is a vertically arranged annular component, and the power generation stacks are solid oxide fuel cell stacks. The burner is disposed in the middle of the annular heat exchanger, and the multiple power generation stacks are arranged circumferentially between the burner and the heat exchanger. Each power generation stack has an air inlet, an air outlet, a fuel inlet, and a fuel outlet. The burner has an air inlet, a fuel inlet, and an exhaust gas outlet. The multiple air outlets are all connected to the air inlet, and the multiple fuel outlets are all connected to the fuel inlet. The heat exchanger has at least three heat exchange channels, and the exhaust gas outlet, the multiple air inlets, and the multiple fuel inlets are each connected to at least one of the heat exchange channels. The heat exchanger is used to preheat the air and fuel introduced into each power generation stack using the waste heat of the exhaust gas discharged from the burner.

[0008] The beneficial effects of the above-mentioned technical solution of the present invention are as follows: by setting multiple power generation stacks between the heat exchanger and the burner, the heat exchanger can preheat the fuel and air using the waste heat of the exhaust gas, and at the same time, together with the burner, heat the power generation stack based on thermal radiation and thermal convection. The preheated fuel and air enter the power generation stack for further heating. This allows the inside and outside of the power generation stack to be heated simultaneously, resulting in rapid heating and a small temperature difference, thus reducing the thermal stress of the power generation stack and increasing the heat utilization rate.

[0009] Based on the above technical solution, the present invention can be further improved as follows: Furthermore, it also includes an inner flow channel base, which is horizontally disposed at the lower inner end of the heat exchanger. The burner is disposed at the middle of the upper end of the inner flow channel base. Multiple mounting positions are circumferentially spaced along the upper edge of the inner flow channel base, each mounting position corresponding to one of the multiple power generation stacks. Each mounting position has an air outlet, an air return outlet, a fuel outlet, and a fuel return outlet. Each power generation stack is installed at its corresponding mounting position. The air inlet, air outlet, fuel inlet, and fuel outlet of each power generation stack correspond to the air outlet at its corresponding mounting position. The air outlet, air return outlet, fuel outlet, and fuel return outlet are connected. The inner flow channel base is also provided with an air inlet, an air return outlet, a fuel inlet, and a fuel return outlet. The inner flow channel base has multiple flow channels inside to connect multiple air outlets to the air inlets, multiple air return outlets to the air return outlets, multiple fuel outlets to the fuel inlets, and multiple fuel return outlets to the fuel return outlets. The air inlet and the fuel inlet are each connected to at least one of the heat exchange channels. The air return outlet is connected to the air inlet, and the fuel return outlet is connected to the fuel inlet.

[0010] The beneficial effect of the above-mentioned further technical solution is that multiple power generation stacks are integrated on the inner flow channel base. At this time, the inner flow channel base serves as both an installation carrier for the power generation stacks and an integrated pipeline within it, thereby simplifying the fuel and air supply path for the power generation stacks.

[0011] Furthermore, the burner is mounted on the upper end of the inner flow channel base via a support frame.

[0012] The beneficial effect of the above-mentioned further technical solution is that it can avoid excessive local heat concentration on the inner flow channel base, thereby preventing the inner flow channel base from deforming due to heat concentration.

[0013] Furthermore, the air outlet, air return outlet, fuel outlet, and fuel return outlet at each of the installation positions are respectively aligned with and connected to the air inlet, air outlet, fuel inlet, and fuel outlet of the corresponding power generation stack.

[0014] The beneficial effect of the above-mentioned further technical solution is that it eliminates the need for any pipelines to connect the power generation stack to the inner flow channel base when it is installed at the mounting position, thereby improving the convenience of power generation stack installation.

[0015] Furthermore, four mounting positions are provided, and the four mounting positions are distributed at the four corners of the quadrilateral. Two flow channels are arranged in parallel at each side of the quadrilateral within the inner flow channel base. The two flow channels corresponding to the same side of the quadrilateral are a fuel flow channel and an air flow channel, respectively. The two ends of each fuel flow channel and air flow channel are close to the two corresponding mounting positions. Any two oppositely distributed fuel flow channels are fuel inlet flow channels, and the remaining two oppositely distributed fuel flow channels are fuel outlet flow channels. Any two oppositely distributed air flow channels are air inlet flow channels, and the remaining two oppositely distributed air flow channels are air outlet flow channels. The ends of the two fuel flow channels and two air flow channels corresponding to any mounting position penetrate through the upper end of the base body, forming an air outlet, an air return outlet, a fuel outlet, and a fuel return outlet at the mounting position. The air inlet is connected to the air inlet flow channel, the air return outlet is connected to the air outlet flow channel, the fuel inlet is connected to the fuel inlet flow channel, and the fuel return outlet is connected to the fuel outlet flow channel.

[0016] The beneficial effect of the above-mentioned further technical solution is that it ensures that the multiple channels in the inner channel base do not cross or interfere with each other, and that the supply of air and fuel flow is stable.

[0017] Furthermore, each of the air inlet, air return outlet, fuel inlet, and fuel return outlet is provided in twos. Each air inlet channel is connected to one air inlet, each air outlet channel is connected to one air return outlet, each fuel inlet channel is connected to one fuel inlet, and each fuel outlet channel is connected to one fuel return outlet.

[0018] The beneficial effect of the above-mentioned further technical solution is that each of the flow channels is independently matched with an interface, such as each air inlet flow channel being independently configured with an air inlet, each air outlet flow channel being independently configured with an air return port, each fuel inlet flow channel being independently configured with a fuel inlet, and each fuel outlet flow channel being independently configured with a fuel return port.

[0019] Furthermore, the burner has a bypass fuel port; And / or the burner also has an ignition device and a thermocouple.

[0020] The beneficial effects of the above-mentioned further technical solution are as follows: This allows for cold start-up of the solid oxide fuel cell system. Since the temperature of the fuel cell stack is much lower than the operating temperature, fuel can be pre-filled into the burner through the bypass fuel port to generate high-temperature exhaust gas and thermal radiation. At this time, the high-temperature exhaust gas is supplied to the fuel and air in the fuel cell stack at the heat exchanger to heat them until the temperature of the fuel cell stack reaches the operating temperature. Once this is achieved, each fuel cell stack can maintain normal operation. At this point, the valve can be closed, and fuel replenishment through the bypass fuel port can be stopped. Furthermore, the installation of ignition devices and thermocouples facilitates ignition within the burner and allows for real-time monitoring of its internal temperature.

[0021] Furthermore, the heat exchanger includes an annular body and multiple shells, the multiple shells being distributed circumferentially at intervals relative to the annular body, and the annular body passing through the multiple shells, dividing each shell into an inner chamber and an outer chamber. The annular body has multiple interlocking spiral channels, with each shell corresponding to one of the spiral channels. One end of each spiral channel communicates with the corresponding inner chamber, and the other end of each spiral channel communicates with the corresponding outer chamber. Each shell is provided with an inner interface communicating with the inner chamber and an outer interface communicating with the outer chamber. Each shell and the corresponding spiral channel together constitute a heat exchange channel.

[0022] The beneficial effects of the above-mentioned further technical solution are as follows: This allows the fluid in multiple swirling channels to fully exchange heat, thereby using the high-temperature exhaust gas generated by combustion to preheat the air and fuel simultaneously, thereby improving the heat utilization efficiency. At the same time, it makes the temperature of the annular body relatively uniform in all directions, and the temperature difference between the preheated air and fuel is smaller, reducing the thermal stress brought by the temperature difference to the power generation stack.

[0023] Furthermore, the exhaust port, air inlet, and fuel inlet are respectively connected to the inner interface of the corresponding heat exchange channel.

[0024] The beneficial effect of the above-mentioned further technical solution is that it makes the pipeline layout of the entire solid oxide fuel cell system simpler and more orderly.

[0025] Furthermore, the fuel for the power generation stack is a combustible gas containing at least one of the elements C, H, and O.

[0026] The beneficial effect of the above-mentioned further technical solutions is that they make the fuel sources for power generation stacks more diverse. Attached Figure Description

[0027] Figure 1 This is a top view of the solid oxide fuel cell system described in an embodiment of the present invention; Figure 2This is an elevation view of the solid oxide fuel cell system described in an embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the assembly of the internal flow channel base, the power generation stack, and the burner in an embodiment of the present invention. Figure 4 This is an elevation view of the inner flow channel base and burner in the combined state as described in this embodiment of the invention; Figure 5 This is a top view of the inner flow channel base and burner in the combined state as described in the embodiment of the present invention; Figure 6 This is a top view of the inner flow channel base described in an embodiment of the present invention; Figure 7 This is a bottom view of the power generation stack described in an embodiment of the present invention; Figure 8 This is a schematic diagram of the internal flow channel of the inner flow channel base in an embodiment of the present invention; Figure 9 This is a cross-sectional view of the heat exchanger described in an embodiment of the present invention; Figure 10 for Figure 9 A partial schematic diagram; Figure 11 This is a schematic diagram showing the distribution of the spiral channels within the spiral body in an embodiment of the present invention.

[0028] In the diagram: 1. Burner; 11. Air inlet; 12. Fuel inlet; 13. Exhaust gas outlet; 14. Bypass fuel inlet; 15. Ignition device; 16. Thermocouple; 2. Heat exchanger; 21. Annular body; 211. Swirling channel; 22. Shell; 221. Inner chamber; 2211. Inner interface; 222. Outer chamber; 2221. Outer interface; 3. Fuel stack; 31. Air inlet; 32. Air outlet; 33. Fuel inlet; 34. Fuel outlet; 4. Inner flow channel base; 41. Mounting position; 411. Air outlet; 412. Air return port; 413. Fuel outlet; 414. Fuel return port; 42a. Fuel flow channel; 42b. Air flow channel; 421. Air inlet; 422. Air return port; 423. Fuel inlet; 424. Fuel return port; 5. Support frame. Detailed Implementation

[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0030] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0031] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "set up," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this technology based on the specific circumstances.

[0032] In the description of this application, spatial relation terms such as "below," "under," "below," "below," "above," "over," etc., are used herein to describe the relationship between one element or feature shown in the figures and other elements or features. It should be understood that, in addition to the orientation shown in the figures, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figures is flipped, an element or feature described as "below" or "under" or "below" of other elements or features will be oriented "above" other elements or features. Therefore, the exemplary terms "below" and "under" can include both upper and lower orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein are interpreted accordingly.

[0033] In the description of this application, the term "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0034] like Figure 1 , Figure 2 and Figure 7 As shown, a solid oxide fuel cell system includes a burner 1, a heat exchanger 2, and multiple fuel cell stacks 3. The heat exchanger 2 is a vertically arranged annular component, and the fuel cell stacks 3 are solid oxide fuel cell stacks. The burner 1 is located in the middle of the annular heat exchanger 2, and the multiple fuel cell stacks 3 are arranged circumferentially between the burner 1 and the heat exchanger 2. Each fuel cell stack 3 has an air inlet 31, an air outlet 32, a fuel inlet 33, and a fuel outlet 34. The burner 1 has an air inlet 1. 1. A fuel inlet 12 and an exhaust outlet 13, multiple air outlets 32 are connected to the air inlet 11, multiple fuel outlets 34 are connected to the fuel inlet 12, the heat exchanger 2 has at least three heat exchange channels, the exhaust outlet 13, multiple air inlets 31 and multiple fuel inlets 33 are each connected to at least one of the heat exchange channels, the heat exchanger 2 is used to preheat the air and fuel introduced into each of the power generation stacks 3 using the waste heat of the exhaust gas discharged from the burner 1. By placing multiple power generation stacks 3 between the heat exchanger 2 and the burner 1, the heat exchanger 2 can preheat the fuel and air using the waste heat of the exhaust gas, while simultaneously heating the power generation stack 3 together with the burner 1 based on thermal radiation and thermal convection. The preheated fuel and air then enter the power generation stack 3 for further heating. This allows the power generation stack 3 to be heated synchronously both inside and out, resulting in rapid heating and a small temperature difference. Consequently, the thermal stress of the power generation stack is reduced, and the heat utilization rate is high.

[0035] In this embodiment, by employing an annular heat exchanger 2 and placing the power generation stack 3 within the annulus of the heat exchanger 2, a higher ambient temperature is provided for the power generation stack 3 to heat up. In addition, the air heat exchange and fuel heat exchange are integrated into one unit, resulting in a smaller temperature difference between the preheated air and fuel, thereby reducing the hazards caused by the temperature difference between the air and fuel after heat exchange. Furthermore, while the burner 1 generates high-temperature exhaust gas, it also provides thermal radiation to the power generation stack 3, significantly accelerating the temperature control speed and reducing the temperature gradient.

[0036] In this embodiment, the power generation stack has an air channel and a fuel channel. The two ends of the air channel are an air inlet 31 and an air outlet 32, respectively, and the two ends of the fuel channel are a fuel inlet 33 and a fuel outlet 34, respectively. The fuel channel and the air channel are independent of each other. The fuel channel serves as the anode of the power generation stack 3, and the air channel serves as the cathode of the power generation stack 3. Its power generation principle is existing technology. In addition, the oxygen and fuel in the air in the power generation stack 3 are usually not completely utilized. The remaining unused fuel and air enter the burner 1 for combustion to heat the entire solid oxide fuel cell system.

[0037] like Figure 1 and Figure 2 As shown, the operating temperature of the power generation stack 3 in this embodiment is approximately 750°C. After the entire solid oxide fuel cell system is operating normally, the heat exchanger 2 and the burner 1 will construct a thermal radiation field within the ring of the heat exchanger 2, and the temperature of this thermal radiation field is close to the operating temperature of the power generation stack 3. This can reduce the heat loss of the power generation stack 3 and heat the power generation stack 3 from the outside. The preheated fuel and air introduced into the power generation stack 3 heat the core of the power generation stack 3, thereby making the temperature distribution of the power generation stack 3 relatively uniform and the heat loss small.

[0038] like Figures 1-8 As shown, the solid oxide fuel cell system in this embodiment further includes an inner flow channel base 4, which is horizontally disposed at the lower inner end of the heat exchanger 2. The burner 1 is disposed at the middle of the upper end of the inner flow channel base 4. Multiple mounting positions 41 are arranged circumferentially at intervals along the upper edge of the inner flow channel base 4. Each mounting position 41 corresponds to one of the multiple power generation stacks 3. Each mounting position 41 has an air outlet 411, an air return port 412, a fuel outlet 413, and a fuel return port 414. Each power generation stack 3 is installed at its corresponding mounting position 41. The air inlet 31, air outlet 32, fuel inlet 33, and fuel outlet 34 of each power generation stack 3 are respectively connected to the air outlet 411, air return port 412, fuel outlet 413, and fuel return port 414 at the corresponding mounting position 41 (specifically, the air inlet 31 is connected to the air outlet 32, air outlet 32, fuel inlet 33, and fuel outlet 34). The air outlet 411 is connected to the air outlet 32, which is connected to the air return port. The fuel inlet 33 is connected to the fuel outlet 413, and the fuel outlet 34 is connected to the fuel return port 414. The inner flow channel base 4 is also provided with an air inlet 421, an air return port 422, a fuel inlet 423, and a fuel return port 424. The inner flow channel base 4 has multiple flow channels to connect multiple air outlets 411 to the air inlet 421, multiple air return ports 412 to the air return port 422, multiple fuel outlets 413 to the fuel inlet 423, and multiple fuel return ports 414 to the fuel return port 424. The air inlet 421 and the fuel inlet 423 are each connected to at least one of the heat exchange channels. The air return port 422 is connected to the air inlet 11, and the fuel return port 424 is connected to the fuel inlet 12. This allows multiple power generation stacks 3 to be integrated on the inner flow channel base 4. At this time, the inner flow channel base 4 serves two purposes: firstly, as the mounting carrier for the power generation stacks 3, and secondly, as the internal flow channel is equivalent to pipeline integration, thereby simplifying the fuel and air supply path for the power generation stacks 3.

[0039] In this embodiment, the inner flow channel base 4 can be a steel plate (specifically, a stainless steel part).

[0040] like Figure 4 As shown, in this embodiment, the burner 1 is mounted on the upper end of the inner flow channel base 4 via a support frame 5. Preferably, a heat insulation pad (in this embodiment, the heat insulation pad can be an asbestos pad, not shown in the figure) is provided at the contact point between the support frame 5 and the inner flow channel base 4. This avoids excessive local heat concentration on the inner flow channel base 4, thereby preventing the inner flow channel base 4 from deforming due to heat concentration.

[0041] In this embodiment, the burner 1 serves as the heat source for the entire solid oxide fuel cell system and is positioned in the middle of the system to improve heat utilization efficiency.

[0042] like Figures 4-8 As shown, in this embodiment, the air outlet 411, air return 412, fuel outlet 413, and fuel return 414 at each mounting position 41 are respectively aligned with and connected to the air inlet 31, air outlet 32, fuel inlet 33, and fuel outlet 34 of the corresponding power generation stack 3. This allows the power generation stack 3 to be installed at the mounting position 41 without any piping to connect to the inner flow channel base 4, thereby improving the ease of installation of the power generation stack 3.

[0043] like Figure 7 As shown, in this embodiment, the air inlet 31, air outlet 32, fuel inlet 33 and fuel outlet 34 of the power generation stack 3 are all located at its lower end, and the power generation stack 3 can be fixedly installed on the inner flow channel base 4 by screws.

[0044] like Figures 1-8As shown, in this embodiment, four mounting positions 41 are provided, and the four mounting positions 41 are distributed at the four corners of the quadrilateral. Two flow channels are arranged parallel to each side of the quadrilateral within the inner flow channel base 4. The two flow channels corresponding to the same side of the quadrilateral are fuel flow channel 42a and air flow channel 42b, respectively. The two ends of each fuel flow channel 42a and air flow channel 42b are close to the corresponding two mounting positions 41. Any two relatively distributed fuel flow channels 42a are fuel inlet channels, and the remaining two relatively distributed fuel flow channels 42a are fuel outlet channels. Air channel 42b is the air inlet channel, and the remaining two relatively distributed air channels 42b are air outlet channels. The ends of the two fuel channels 42a and the two air channels 42b corresponding to any of the mounting positions 41 all penetrate the upper end of the base body, forming an air outlet 411, an air return port 412, a fuel outlet 413, and a fuel return port 414 at the mounting position 41. The air inlet 421 communicates with the air inlet channel, the air return port 422 communicates with the air outlet channel, the fuel inlet 423 communicates with the fuel inlet channel, and the fuel return port 424 communicates with the fuel outlet channel. This ensures that the multiple channels within the inner channel base 4 do not cross or interfere with each other, and provides a stable supply of air and fuel flow.

[0045] like Figures 1-6 As shown, the quadrilateral in this embodiment can be a rectangle, a parallelogram, a trapezoid, etc., with a rectangle being preferred.

[0046] like Figure 6 and Figure 8 As shown, in this embodiment, there are two of each of the following: air inlet 421, air return port 422, fuel inlet 423, and fuel return port 424. Each air inlet channel is connected to one air inlet 421, each air outlet channel is connected to one air return port 422, each fuel inlet channel is connected to one fuel inlet 423, and each fuel outlet channel is connected to one fuel return port 424. This allows each channel to be independently matched with an interface (preferably located in the middle of the corresponding channel length direction; in this embodiment, the air inlet 421, air return port 422, fuel inlet 423, and fuel return port 424 are all interfaces). For example, each air inlet channel is independently configured with one air inlet 421, each air outlet channel is independently configured with one air return port 422, each fuel inlet channel is independently configured with one fuel inlet 423, and each fuel outlet channel is independently configured with one fuel return port 424.

[0047] like Figures 1-4As shown, the burner 1 in this embodiment has a bypass fuel port 14, and a valve is provided on the bypass fuel port 14. The burner 1 in this embodiment also has an ignition device 15 and a thermocouple 16. This allows for cold start when the solid oxide fuel cell system is first started. Since the temperature of the power generation stack 3 is much lower than the operating temperature, fuel can be pre-added to the burner 1 through the bypass fuel port 14 to generate high-temperature exhaust gas and thermal radiation. At this time, the high-temperature exhaust gas is supplied to the fuel and air in the power generation stack 3 at the heat exchanger 2 to heat them until the temperature of the power generation stack 3 reaches the operating temperature. At this time, each power generation stack 3 can maintain normal operation. At this time, the valve 15 can be closed and the fuel replenishment from the bypass fuel port 14 can be stopped. The ignition device 15 and thermocouple 16 facilitate ignition in the burner 1 and real-time monitoring of its internal temperature.

[0048] The structure of the ignition device 15 and the thermocouple 16 described in this embodiment, as well as their arrangement on the burner 1, are all existing technologies.

[0049] Preferred, such as Figures 1-4 As shown, in this embodiment, the burner 1 has two air inlets 11, two fuel inlets 12, and two exhaust outlets 13. At this time, the two air inlets 11 correspond one-to-one with the two air return ports 422, and each air inlet 11 is connected to the corresponding air return port 422. The two fuel inlets 12 correspond one-to-one with the two fuel return ports 424, and each fuel inlet 12 is connected to the corresponding fuel return port 424.

[0050] like Figure 9 and Figure 10As shown, in this embodiment, the heat exchanger 2 includes an annular body 21 and multiple shells 22. The multiple shells 22 are distributed circumferentially relative to the annular body 21, and the annular body 21 passes through the multiple shells 22, dividing each shell 22 into an inner chamber 221 and an outer chamber 222. The annular body 21 has multiple interlocking spiral channels 211. The multiple shells 22 correspond one-to-one with the multiple spiral channels 211. One end of each spiral channel 211 is connected to the corresponding inner chamber 221, and the other end of each spiral channel 211 is connected to the corresponding outer chamber 222. The shells 22 are provided with an inner interface 2211 that communicates with the inner chamber 221 and an outer interface 2221 that communicates with the outer chamber 222. Each shell 22 and the corresponding spiral channel 211 together constitute a heat exchange channel. This allows the fluids within the multiple spiral channels 211 to fully exchange heat, thereby using the high-temperature exhaust gas generated by combustion to preheat both air and fuel simultaneously, thus improving heat utilization efficiency. At the same time, it makes the temperature of the annular body 21 relatively uniform in all directions, resulting in a smaller temperature difference between the preheated air and fuel, reducing the thermal stress caused by the temperature difference to the power generation stack 3.

[0051] in, Figure 10 Point A in the diagram indicates the connection between one end of the spiral channel 211 and the inner chamber 221, while point B indicates the connection between the other end of the spiral channel 211 and the outer chamber 222.

[0052] In this embodiment, each of the spiral channels 211 can be coiled multiple times. The arrangement of the multiple spiral channels 211 is similar to two spiraling mosquito coils that can be interlocked to form an approximately circular mosquito coil disc. The difference is that in this embodiment, multiple spiral channels 211 are interlocked to form an annular body 21.

[0053] like Figure 1 and Figure 2 As shown, in this embodiment, the exhaust port 13, air inlet 421, and fuel inlet 423 are respectively connected to the inner interface 2211 of the corresponding heat exchange channel. This makes the piping layout of the entire solid oxide fuel cell system simpler and more orderly.

[0054] like Figure 1 and Figure 2 As shown, in this embodiment, each of the two exhaust ports 13 is independently matched with a heat exchange channel, and the two corresponding external interfaces 2221 are used to discharge exhaust gas to the outside.

[0055] In this embodiment, the external interface 2221 corresponding to the air inlet 421 is used to introduce air, while the external interface 2221 corresponding to the fuel inlet 423 is used to introduce fuel. At this time, the air and fuel introduced through the external interface 2221 are preheated by the heat exchanger 2.

[0056] like Figure 1 , Figure 2 , Figure 9 , Figure 10 and Figure 11 As shown, the heat exchanger 2 in this embodiment can be provided with four heat exchange channels, two of which correspond to the exhaust gas (at this time, each of the two exhaust gas outlets 13 is independently matched with one of the heat exchange channels), while the remaining two heat exchange channels correspond to air and fuel respectively (at this time, the two air inlets 421 are connected to the same internal interface 2211, and the two fuel inlets 423 are also connected to the same internal interface 2211).

[0057] See details Figure 11 In this embodiment, the two ends of the four spiral channels 211 are close to each other in the circumferential direction. One end of each of the four spiral channels 211 is located on the inner wall of the annular body 21 and is distributed circumferentially on the inner wall. The other ends of the four spiral channels 211 are located on the outer wall of the annular body 21 and are distributed circumferentially on the outer wall. For example, A1 and A2 are the two ends of a spiral channel 211, B1 and B2 are the two ends of a spiral channel 211, C1 and C2 are the two ends of a spiral channel 211, and D1 and D2 are the two ends of a spiral channel 211.

[0058] In this embodiment, the four spiral channels 211 are interlocked in a concentric and equidistant spiral manner, and the phase difference between any two adjacent spiral channels 211 is 90°. In short, the heat exchanger 2 in this embodiment is essentially a four-channel plate heat exchanger.

[0059] In this embodiment, the two spiral channels 211 corresponding to air and fuel are staggered (that is, they are not adjacent; specifically, there is at least one spiral channel 211 corresponding to exhaust gas between them). In addition, the flow direction of fuel and air in the annular body 21 is different from the flow direction of exhaust gas in the annular body 21. This can further improve the heat exchange efficiency. That is, if fuel and air flow in a clockwise direction in the annular body 21, exhaust gas flows in a counterclockwise direction in the annular body 21; if fuel and air flow in a counterclockwise direction in the annular body 21, exhaust gas flows in a clockwise direction in the annular body 21.

[0060] Preferably, in this embodiment, the four shells 22 are evenly distributed along the circumferential direction on the annular body 21, and in this embodiment, the shells 22 of the two heat exchange channels corresponding to the flue gas are relatively distributed in the circumferential direction of the annular body 21.

[0061] In this embodiment, the fuel for the power generation stack 3 is a combustible gas containing at least one of the elements C, H, and O. This makes the fuel source for the power generation stack 3 widely available. The fuel in this embodiment can be CO, H2, CH4, or C2H2, etc.

[0062] In this embodiment, the connection between the inner flow channel base 4, the heat exchanger 2 and the burner 1 can be made by means of a pipe.

[0063] While embodiments or examples of this disclosure have been described with reference to the accompanying drawings, it should be understood that the above embodiments are merely exemplary embodiments or examples, and the scope of the invention is not limited by these embodiments or examples, but only by the granted claims and their equivalents. Various elements in the embodiments or examples may be omitted or replaced by their equivalents. Furthermore, the steps may be performed in a different order than that described in this disclosure. Further, various elements in the embodiments or examples may be combined in various ways. Importantly, as the technology evolves, many elements described herein can be replaced by equivalents that appear after this disclosure.

Claims

1. A solid oxide fuel cell system, characterized in that, The device includes a burner (1), a heat exchanger (2), and multiple fuel cell stacks (3). The heat exchanger (2) is a vertically arranged annular component, and the fuel cell stacks (3) are solid oxide fuel cell stacks. The burner (1) is located in the middle of the annular heat exchanger (2). Multiple fuel cell stacks (3) are arranged circumferentially between the burner (1) and the heat exchanger (2). Each fuel cell stack (3) has an air inlet (31), an air outlet (32), a fuel inlet (33), and a fuel outlet (34). The burner (1) has an air inlet (11) and a fuel outlet (34). The heat exchanger (2) has at least three heat exchange channels. The exhaust port (12) and exhaust port (13) are connected to the air inlet (11), and the fuel outlet (34) is connected to the fuel inlet (12). The exhaust port (13), the multiple air inlets (31) and the multiple fuel inlets (33) are each connected to at least one of the heat exchange channels. The heat exchanger (2) is used to preheat the air and fuel introduced into each of the power generation stacks (3) by utilizing the waste heat of the exhaust gas discharged from the burner (1).

2. The solid oxide fuel cell system according to claim 1, characterized in that, It also includes an inner flow channel base (4), which is horizontally arranged at the lower inner end of the heat exchanger (2). The burner (1) is arranged at the middle of the upper end of the inner flow channel base (4). Multiple mounting positions (41) are arranged circumferentially at the upper edge of the inner flow channel base (4). The multiple mounting positions (41) correspond one-to-one with the multiple power generation stacks (3). Each mounting position (41) has an air outlet (411), an air return port (412), a fuel outlet (413), and a fuel return port (414). Each power generation stack (3) is installed at the corresponding mounting position (41). The air inlet (31), air outlet (32), fuel inlet (33), and fuel outlet (34) of each power generation stack (3) correspond to the air outlet (411), air return port (412), and fuel return port (414) of the corresponding mounting position (41), respectively. The fuel port (413) and the return fuel port (414) are connected. The inner flow channel base (4) is also provided with an air inlet (421), an air return port (422), a fuel inlet (423) and a fuel return port (424). The inner flow channel base (4) has multiple flow channels inside to connect multiple air outlets (411) with the air inlet (421), multiple air return ports (412) with the air return port (422), multiple fuel outlets (413) with the fuel inlet (423), and multiple fuel return ports (414) with the fuel return port (424). The air inlet (421) and the fuel inlet (423) are respectively connected to at least one of the heat exchange channels. The air return port (422) is connected to the air inlet (11), and the fuel return port (424) is connected to the fuel inlet (12).

3. The solid oxide fuel cell system according to claim 2, characterized in that, The burner (1) is mounted on the upper end of the inner flow channel base (4) via a support frame (5).

4. The solid oxide fuel cell system according to claim 2, characterized in that, The air outlet (411), air return (412), fuel outlet (413) and fuel return (414) at each of the mounting positions (41) are respectively aligned with and connected to the air inlet (31), air outlet (32), fuel inlet (33) and fuel outlet (34) of the corresponding power generation stack (3).

5. The solid oxide fuel cell system according to claim 2, characterized in that, Four mounting positions (41) are provided, and the four mounting positions (41) are distributed at the four corners of the quadrilateral. Two flow channels are arranged in parallel at each side of the quadrilateral in the inner flow channel base (4). The two flow channels corresponding to the same side of the quadrilateral are fuel flow channel (42a) and air flow channel (42b). The two ends of each fuel flow channel (42a) and air flow channel (42b) are close to the two corresponding mounting positions (41). Any two oppositely distributed fuel flow channels (42a) are fuel inlet flow channels, and the remaining two oppositely distributed fuel flow channels (42a) are fuel outlet flow channels. Any two oppositely distributed air flow channels (42b) are fuel outlet flow channels. The first is the air inlet channel, and the remaining two relatively distributed air inlets (42b) are the air outlet channels. The ends of the two fuel inlets (42a) and two air inlets (42b) corresponding to any of the mounting positions (41) penetrate the upper end of the base body and form an air outlet (411), an air return outlet (412), a fuel outlet (413), and a fuel return outlet (414) at the mounting position (41). The air inlet (421) is connected to the air inlet channel, the air return outlet (422) is connected to the air outlet channel, the fuel inlet (423) is connected to the fuel inlet channel, and the fuel return outlet (424) is connected to the fuel outlet channel.

6. The solid oxide fuel cell system according to claim 5, characterized in that, Each of the following is provided with two air inlets (421), two air outlets (422), two fuel inlets (423), and two fuel outlets (424): each air inlet channel is connected to one air inlet (421), each air outlet channel is connected to one air outlet (422), each fuel inlet channel is connected to one fuel inlet (423), and each fuel outlet channel is connected to one fuel outlet (424).

7. The solid oxide fuel cell system according to claim 5, characterized in that, The burner (1) has a bypass fuel port (14). And / or the burner (1) also has an ignition device (15) and a thermocouple (16).

8. The solid oxide fuel cell system according to any one of claims 2-7, characterized in that, The heat exchanger (2) includes an annular body (21) and a plurality of shells (22). The plurality of shells (22) are circumferentially spaced relative to the annular body (21), and the annular body (21) passes through the plurality of shells (22), dividing each shell (22) into an inner chamber (221) and an outer chamber (222). The annular body (21) has a plurality of interlocking spiral channels (211), and the plurality of shells (22) and the plurality of spiral channels (211) are one-to-one. Correspondingly, one end of each spiral channel (211) is connected to the corresponding inner chamber (221), and the other end of each spiral channel (211) is connected to the corresponding outer chamber (222). The shell (22) is provided with an inner interface (2211) connected to the inner chamber (221) and an outer interface (2221) connected to the outer chamber (222). Each shell (22) and the corresponding spiral channel (211) together constitute a heat exchange channel.

9. The solid oxide fuel cell system according to claim 8, characterized in that, The exhaust port (13), air inlet (421) and fuel inlet (423) are respectively connected to the inner interface (2211) of the corresponding heat exchange channel.

10. The solid oxide fuel cell system according to any one of claims 1-7, characterized in that, The fuel for the power generation stack (3) is a combustible gas containing at least one of the elements C, H and O.

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