Fuel cell anode tail gas combustor and control method thereof

Abstract

The application belongs to the technical field of fuel cell systems, and discloses a fuel cell anode tail gas burner and a control method thereof. The first air inlet and the natural gas inlet of the natural gas premixing body are communicated with the natural gas premixing cavity. The first combustion body is provided with a communicated anode tail gas combustion cavity, a natural gas combustion cavity and a first gas outlet. The natural gas premixing cavity is communicated with the natural gas combustion cavity. The anode tail gas guide element and the air guide element are both communicated with the anode tail gas combustion cavity. The catalytic premixing body is provided with a catalytic premixing cavity, a second air inlet and a second gas outlet. The second air inlet, the second gas outlet and the first gas outlet are all communicated with the catalytic premixing cavity. The second combustion body is provided with a containing cavity, a third air inlet and a third gas outlet. The containing cavity contains a catalytic carrier. The third air inlet, the third gas outlet and the second gas outlet are all communicated with the containing cavity. The wide-range regulation and complete combustion of fuel can be realized.

Description

Technical Field

[0001] This invention relates to the field of fuel cell system technology, and in particular to a fuel cell anode tail gas burner and its control method. Background Technology

[0002] The anode burner in a fuel cell system is the heat source and must possess high heat flow and a wide fuel range to enable rapid start-up and the handling of variable-component combustible materials. During startup, the fuel cell system requires air preheating, which is typically achieved using electric heaters or burners. However, high-power electric heaters have stringent circuit requirements and insufficient high-temperature heating capacity. When using a burner, the temperature of the air entering the burner continuously increases as the fuel cell system operates, reducing the fuel supply. Maintaining a stable flame necessitates diffusion combustion or porous media combustion. Conventional diffusion flame burners have long flame lengths and large device sizes, hindering integrated systems; porous media burners are limited by porous media material processing technology, making large-scale application difficult. If a catalytic burner is used, it requires a certain initial temperature to start combustion, making it unsuitable for supplying initial heat during fuel cell system startup. As a result, existing burners cannot adapt to both the start-up conditions of fuel cell systems and the variable composition conditions caused by the reduction of combustible components in the anode exhaust gas due to increased fuel utilization. This makes it impossible to avoid flameout caused by unstable combustion, which not only wastes energy but also increases the risk of equipment and pollutant emissions due to the emission of combustible substances. Summary of the Invention

[0003] The purpose of this invention is to provide a fuel cell anode exhaust gas burner and its control method to solve the problem that existing burners cannot be applied to both the start-up conditions of fuel cells and the variable composition conditions where the combustible components of the anode exhaust gas decrease as the fuel utilization rate of the fuel cell increases, thus failing to achieve wide-range adjustment and stable combustion.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] The fuel cell anode exhaust gas burner includes:

[0006] A natural gas premix, wherein the natural gas premix is ​​provided with a first air inlet, a natural gas inlet and a natural gas premixing chamber, and the first air inlet and the natural gas inlet are both connected to the natural gas premixing chamber;

[0007] An air inlet and an anode tail gas inlet are provided, wherein the anode tail gas inlet is fixedly inserted into the air inlet and the air inlet is fixedly inserted into the natural gas premix. The anode tail gas inlet is provided with an anode tail gas inlet.

[0008] The first combustion body is provided with a connected anode exhaust gas combustion chamber, a natural gas combustion chamber and a first gas outlet. The natural gas premixing chamber is connected to the natural gas combustion chamber. The anode exhaust gas inlet and the air inlet are both connected to the anode exhaust gas combustion chamber.

[0009] A catalytic premixer is provided with a catalytic premixing chamber, a second air inlet and a second gas outlet, wherein the second air inlet, the second gas outlet and the first gas outlet are all connected to the catalytic premixing chamber.

[0010] The second combustion body is provided with a receiving cavity, a third air inlet and a third gas outlet. The receiving cavity contains a catalyst carrier. The third air inlet, the third gas outlet and the second gas outlet are all connected to the receiving cavity.

[0011] An air input pipe is provided, and the first air inlet, the air guide, the second air inlet, and the third air inlet are all connected to the air input pipe.

[0012] As a preferred embodiment of the aforementioned fuel cell anode tail gas burner, the natural gas premix includes a premix outer shell, a premix middle shell, and a premix inner shell. The premix middle shell passes through the premix outer shell, and the premix inner shell passes through the premix middle shell. The premix outer shell is provided with the natural gas inlet. A natural gas distribution chamber is formed between the premix outer shell and the premix middle shell. A natural gas premixing chamber and the first air inlet are formed between the premix middle shell and the premix inner shell. The premix middle shell is provided with a connecting hole, and the two ends of the connecting hole are respectively connected to the natural gas distribution chamber and the natural gas premixing chamber.

[0013] As a preferred embodiment of the aforementioned fuel cell anode exhaust gas burner, the air inlet includes a first connecting portion, a second connecting portion, and a plurality of first air swirl vanes. The first connecting portion is fixedly sleeved on the anode exhaust gas inlet, and the second connecting portion is fixedly inserted into the premixed inner shell. One end of each first air swirl vane is fixedly connected to the first connecting portion, and the other end is fixedly connected to the second connecting portion. The plurality of first air swirl vanes are spaced apart circumferentially along the first connecting portion. The first connecting portion is provided with a plurality of fourth air inlets spaced apart circumferentially. The two ends of each fourth air inlet are respectively connected to the air input pipe and the anode exhaust gas combustion chamber.

[0014] As a preferred embodiment of the above-mentioned fuel cell anode tail gas burner, the first burner includes a burner shell and a burner inner shell. The burner shell is fixedly connected to the premixed body shell. A mixed gas distribution chamber is formed between the burner shell and the burner inner shell. The mixed gas distribution chamber is connected to the natural gas premixed chamber. The burner inner shell is provided with a mixed gas injection hole, the anode tail gas combustion chamber and the natural gas combustion chamber. The two ends of the mixed gas injection hole are respectively connected to the mixed gas distribution chamber and the natural gas combustion chamber.

[0015] As a preferred embodiment of the above-mentioned fuel cell anode tail gas burner, a plurality of second air swirl vanes are provided between the first air inlet and the natural gas premixing chamber; or, a plurality of second air swirl vanes are provided between the natural gas premixing chamber and the mixed gas distribution chamber.

[0016] As a preferred embodiment of the above-mentioned fuel cell anode tail gas burner, the inner shell of the burner is provided with a flow equalization plate, which is located in the mixed gas distribution chamber.

[0017] As a preferred embodiment of the aforementioned fuel cell anode tail gas burner, the inner wall of the natural gas combustion chamber is provided with a metal fiber mesh.

[0018] As a preferred embodiment of the above-mentioned fuel cell anode exhaust gas burner, the anode exhaust gas inlet extends into the anode exhaust gas combustion chamber, and the anode exhaust gas inlet is also provided with an anode exhaust gas injection hole, which is connected to the anode exhaust gas combustion chamber.

[0019] As a preferred embodiment of the above-mentioned fuel cell anode tail gas burner, the fuel cell anode tail gas burner further includes a burner housing, wherein the natural gas premix, the first burner, the catalytic premix, and the second burner are sequentially connected and all located within the burner housing, an air distribution cavity is formed between the burner housing and the natural gas premix, the first burner, the catalytic premix, and the second burner, a fifth air inlet is formed between the burner housing and the natural gas premix, the second air inlet, the third air inlet, and the fifth air inlet are all connected to the air distribution cavity, and the fifth air inlet is connected to the air input pipe.

[0020] As a preferred embodiment of the aforementioned fuel cell anode exhaust gas burner, the inner wall of the anode exhaust gas combustion chamber is fixedly provided with a first heat-insulating and fire-resistant layer.

[0021] As a preferred embodiment of the aforementioned fuel cell anode exhaust gas burner, a second heat-insulating and fire-resistant layer is provided between the inner wall of the accommodating cavity and the catalyst support.

[0022] The present invention also provides a control method for a fuel cell anode exhaust gas burner, employing the above-mentioned fuel cell anode exhaust gas burner, comprising:

[0023] S1: Introduce air into the fuel cell anode exhaust gas burner;

[0024] S2: Natural gas is introduced into the fuel cell anode tail gas burner and the natural gas combustion chamber is ignited;

[0025] S3: Perform flame detection on the natural gas combustion chamber to determine whether a flame is generated in the natural gas combustion chamber;

[0026] If so, proceed to S4;

[0027] S4: Adjust the natural gas flow rate based on the gas temperature at the third outlet and the set burner outlet temperature;

[0028] S5: Detects the air temperature inside the air inlet pipe;

[0029] S6: Determine whether the air temperature in the air input pipe is greater than the set burner inlet air temperature;

[0030] If so, proceed to S7;

[0031] S7: Introduce anode exhaust gas into the fuel cell anode exhaust gas burner;

[0032] S8: Real-time flame detection of the anode exhaust gas combustion chamber to determine whether a flame is generated in the anode exhaust gas combustion chamber;

[0033] If so, then proceed with flame combustion and S10;

[0034] If not, proceed to S9;

[0035] S9: Determine whether the fuel cell anode tail gas burner is performing stable catalytic combustion based on the gas temperature decay rate at the third outlet and the temperature of the catalyst support;

[0036] If so, proceed to S10;

[0037] If not, the fuel cell anode exhaust combustor will shut down;

[0038] S10: Adjust the natural gas flow rate based on the gas temperature at the third outlet and the set burner outlet temperature.

[0039] As a preferred embodiment of the control method for the aforementioned fuel cell anode tail gas burner, determining whether the fuel cell anode tail gas burner is undergoing stable catalytic combustion based on the gas temperature decay rate at the third outlet and the temperature of the catalyst support includes:

[0040] Determine whether the gas temperature decay rate at the third outlet is greater than the set temperature decay rate;

[0041] If so, then proceed to S91;

[0042] If not, the fuel cell anode exhaust gas burner performs stable catalytic combustion;

[0043] S91: Determine whether the temperature of the catalyst support increases within a set time;

[0044] If so, the fuel cell anode exhaust gas burner will perform stable catalytic combustion;

[0045] If not, then the fuel cell anode exhaust combustor is not undergoing stable catalytic combustion.

[0046] As a preferred embodiment of the control method for the above-mentioned fuel cell anode tail gas burner, in S3, if no flame is generated in the natural gas combustion chamber, then proceed to S31;

[0047] S31: Stop supplying natural gas to the fuel cell anode tail gas burner and supply air to the fuel cell anode tail gas burner to purge the natural gas combustion chamber;

[0048] S32: Determine whether the number of ignitions in the natural gas combustion chamber is greater than the set number;

[0049] If so, the fuel cell anode exhaust gas burner will shut down;

[0050] If not, return to S2.

[0051] As a preferred embodiment of the control method for the aforementioned fuel cell anode tail gas burner, adjusting the natural gas flow rate based on the gas temperature at the third outlet and the set burner outlet temperature includes:

[0052] Determine whether the gas temperature at the third outlet is greater than the set burner outlet temperature;

[0053] If so, reduce the natural gas flow rate;

[0054] If not, increase the natural gas flow rate.

[0055] As a preferred embodiment of the control method for the above-mentioned fuel cell anode exhaust gas burner, between S7 and S8, the method further includes: igniting the anode exhaust gas combustion chamber.

[0056] The beneficial effects of this invention are:

[0057] This invention provides a fuel cell anode tail gas burner and its control method. In the fuel cell system startup phase, natural gas and air undergo fully premixed combustion in the natural gas combustion chamber, followed by the introduction of anode tail gas. Initially, the anode tail gas has a high content of combustible components, enabling flame combustion in the first combustion chamber. As the combustible component content decreases until it can no longer support flame combustion, the anode tail gas, natural gas, and air can still undergo stable catalytic combustion within the catalytic carrier. Existing burners cannot achieve stable combustion when the combustible components in the anode tail gas are too low. This fuel cell anode tail gas burner not only enables stable catalytic combustion even with low combustible components in the anode tail gas, adapting to variable composition conditions with decreasing combustible components in the anode tail gas, but also adapts to the fuel cell system startup phase. It achieves wide-range fuel regulation and complete combustion, reduces pollutant emissions, improves thermal efficiency, and saves energy. Attached Figure Description

[0058] Figure 1 This is a cross-sectional view of the fuel cell anode exhaust gas burner provided in a specific embodiment of the present invention. Figure 1 ;

[0059] Figure 2 This is a cross-sectional view of the fuel cell anode exhaust gas burner provided in a specific embodiment of the present invention. Figure 2 ;

[0060] Figure 3 This is a cross-sectional view of the fuel cell anode exhaust gas burner provided in a specific embodiment of the present invention. Figure 3 ;

[0061] Figure 4 This is a side view of the fuel cell anode exhaust gas burner provided in a specific embodiment of the present invention.

[0062] In the picture:

[0063] 11. Premix outer shell; 12. Premix middle shell; 13. Premix inner shell; 14. First air inlet; 15. Natural gas inlet; 16. Natural gas distribution chamber; 17. Natural gas premixing chamber; 18. Connecting hole; 19. Second air swirl vane;

[0064] 2. Anode exhaust gas inlet; 21. Anode exhaust gas inlet; 22. Anode exhaust gas injection hole;

[0065] 31. First connecting part; 32. Second connecting part; 33. First air swirl vane; 34. Fourth air inlet;

[0066] 41. Combustion body outer shell; 42. Combustion body inner shell; 43. Mixture distribution chamber; 44. Anode exhaust gas combustion chamber; 45. Natural gas combustion chamber; 46. Mixture injection port;

[0067] 5. Catalytic premix; 51. Second air inlet;

[0068] 6. Second combustion medium; 61. Catalytic carrier; 62. Second heat-insulating and refractory layer; 63. Third air inlet;

[0069] 7. Burner housing; 71. Air distribution chamber; 72. Fifth air inlet;

[0070] 8. First heat-insulating and fire-resistant layer;

[0071] 9. Igniter channel;

[0072] 10. Ignition needle. Detailed Implementation

[0073] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0074] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0075] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0076] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0077] This invention provides a fuel cell anode exhaust gas burner, such as... Figure 1-4 As shown, the fuel cell anode exhaust gas burner includes a natural gas premix, an air inlet, an anode exhaust gas inlet 2, a first combustor, a catalytic premix 5, a second combustor 6, and an air input pipe. The natural gas premix has a first air inlet 14, a natural gas inlet 15, and a natural gas premixing chamber 17. Both the first air inlet 14 and the natural gas inlet 15 are connected to the natural gas premixing chamber 17. The anode exhaust gas inlet 2 is fixedly inserted through the air inlet, and the air inlet is fixedly inserted through the natural gas premix. The anode exhaust gas inlet 2 has an anode exhaust gas inlet 21. The first combustor has a connected anode exhaust gas combustion chamber 44, a natural gas combustion chamber 45, and a first gas outlet. The premixing chamber 17 is connected to the natural gas combustion chamber 45. The anode tail gas inlet 2 and the air inlet are both connected to the anode tail gas combustion chamber 44. The catalytic premixing body 5 is provided with a catalytic premixing chamber, a second air inlet 51 and a second gas outlet. The second air inlet 51, the second gas outlet and the first gas outlet are all connected to the catalytic premixing chamber. The second combustion body 6 is provided with a receiving chamber, a third air inlet 63 and a third gas outlet. The receiving chamber contains a catalytic carrier 61. The third air inlet 63, the third gas outlet and the second gas outlet are all connected to the receiving chamber. The first air inlet 14, the air inlet, the second air inlet 51 and the third air inlet 63 are all connected to the air input pipe.

[0078] like Figure 1-4As shown, in the fuel cell anode tail gas burner, during the start-up operation of the fuel cell system, air is introduced into the air input pipe. Air enters the natural gas premixing chamber 17 from the first air inlet 14, the catalytic premixing chamber from the second air inlet 51, the receiving chamber from the third air inlet 63, and the anode tail gas combustion zone from the air inlet. Natural gas is also introduced into the natural gas inlet 15. After mixing in the natural gas premixing chamber 17, the air and natural gas enter the natural gas combustion chamber 45 and are burned. The high-temperature flue gas generated by the combustion of air and natural gas in the natural gas combustion chamber 45 enters the catalytic premixing chamber and mixes with... Air entering the catalytic premixing chamber through the second air inlet 51 mixes with the air and then enters the second combustor 6, preheating the catalytic carrier 61 of the second combustor 6. High-temperature flue gas passing through the containment chamber mixes with air entering the containment chamber through the third air inlet 63 and flows out from the third outlet. As the fuel cell operates, the temperature of the air entering the air input pipe continuously increases. To maintain a constant gas temperature at the third outlet, the natural gas flow rate needs to be reduced. Under the condition of constant air flow rate, the excess air coefficient of the mixture formed by natural gas and air gradually increases. When the air temperature in the air input pipe is higher than the set burner inlet air temperature, anode tail gas is generated and introduced into the anode tail gas inlet 21. The anode tail gas and air mix in the anode tail gas combustion chamber 44, potentially producing a flame. It is understood that whether the anode tail gas and air can burn and produce a flame after mixing in the anode tail gas combustion chamber 44 depends on the content of combustible components in the anode tail gas. When the content of combustible components in the anode tail gas is high, the anode tail gas can be burned in the anode tail gas combustion chamber 44 to generate a flame. At this time, flame combustion occurs in the anode tail gas burner of the fuel cell. When the content of combustible components in the anode tail gas decreases until it can no longer support the combustion of the anode tail gas in the anode tail gas combustion chamber 44, and the flame in the anode tail gas combustion chamber 44 is extinguished, the anode tail gas burner of the fuel cell can still carry out stable catalytic combustion. The anode tail gas, natural gas and air are burned in the catalyst carrier 61 to continue to supply heat.

[0079] In this fuel cell anode tail gas burner, during the fuel cell system startup, natural gas and air undergo fully premixed combustion in the natural gas combustion chamber 45, followed by the introduction of anode tail gas. Initially, the anode tail gas has a high content of combustible components, enabling flame combustion within the first combustion chamber. As the content of combustible components in the anode tail gas decreases until it can no longer support flame combustion, the anode tail gas, natural gas, and air can still undergo stable catalytic combustion within the catalytic carrier 61 after the flame is extinguished. Existing burners cannot achieve stable combustion when the combustible components in the anode tail gas are too low. This fuel cell anode tail gas burner not only enables stable catalytic combustion even when the combustible components in the anode tail gas are too low, adapting to variable composition conditions with decreasing combustible components in the anode tail gas, but also adapting to the fuel cell system startup conditions. It achieves wide-range fuel regulation and complete combustion, reducing pollutant emissions, improving thermal efficiency, and saving energy.

[0080] Understandably, the air entering the catalytic premixing chamber from the second air inlet 51 is used to cool the high-temperature flue gas entering the catalytic premixing chamber, preventing damage to the catalyst. The air entering the receiving chamber from the third air inlet 63 is used to cool the high-temperature flue gas at the third outlet. Optionally, there are multiple second air inlets 51 and multiple third air inlets 63, with the multiple second air inlets 51 spaced apart circumferentially along the catalytic premix body 5, and the multiple third air inlets 63 spaced apart circumferentially along the second combustor 6.

[0081] Understandably, the fuel cell system includes an air preheater that heats the air entering the air inlet pipe, and the high-temperature flue gas flowing out from the third outlet provides heat to the air preheater.

[0082] Optionally, the natural gas premix includes a premix outer shell 11, a premix middle shell 12, and a premix inner shell 13. The premix middle shell 12 passes through the premix outer shell 11, and the premix inner shell 13 passes through the premix middle shell 12. The premix outer shell 11 is provided with a natural gas inlet 15. A natural gas distribution chamber 16 is formed between the premix outer shell 11 and the premix middle shell 12. A natural gas premixing chamber 17 and a first air inlet 14 are formed between the premix middle shell 12 and the premix inner shell 13. The premix middle shell 12 is provided with a connecting hole 18, and both ends of the connecting hole 18 are connected to the natural gas distribution chamber 16 and the natural gas premixing chamber 17, respectively. Natural gas enters the natural gas distribution chamber 16 through the natural gas inlet 15, and then enters the natural gas premixing chamber 17 through the connecting hole 18. Air enters the natural gas premixing chamber 17 through the first air inlet 14. Natural gas and air mix in the natural gas premixing chamber 17 to form a mixed gas.

[0083] Optionally, the premix outer shell 11, the premix middle shell 12, and the premix inner shell 13 are all cylindrical and coaxially arranged. Multiple connecting holes 18 are provided, spaced apart along the circumference of the premix middle shell 12. This allows natural gas to enter the natural gas premix chamber 17 uniformly.

[0084] Optionally, the first combustor includes a combustor outer shell 41 and a combustor inner shell 42. The combustor outer shell 41 is fixedly connected to the premixing body outer shell 11. A mixture distribution chamber 43 is formed between the combustor outer shell 41 and the combustor inner shell 42. The mixture distribution chamber 43 is connected to the natural gas premixing chamber 17. The combustor inner shell 42 is provided with a mixture injection hole 46, an anode tail gas combustion chamber 44, and a natural gas combustion chamber 45. The two ends of the mixture injection hole 46 are respectively connected to the mixture distribution chamber 43 and the natural gas combustion chamber 45. The mixture formed by mixing natural gas and air in the natural gas premixing chamber 17 enters the mixture distribution chamber 43 from the natural gas premixing chamber 17 and enters the natural gas combustion chamber 45 through the mixture injection hole 46. Optionally, both the combustor inner shell 42 and the combustor outer shell 41 are cylindrical and coaxially arranged. There are multiple mixture injection holes 46, which are spaced apart along the circumferential direction of the combustor inner shell 42. Natural gas is injected radially along the inner shell 42 of the combustion chamber and undergoes fully premixed combustion within the natural gas combustion chamber 45. The radial jet structure effectively stabilizes the flame and improves flame stability.

[0085] Optionally, a plurality of second air swirl vanes 19 are provided at intervals between the natural gas premixing chamber 17 and the mixed gas distribution chamber 43. After the mixed gas passes through the second air swirl vanes 19, it can be fully mixed with the natural gas before entering the mixed gas distribution chamber 43. As an alternative, a plurality of second air swirl vanes 19 are provided at intervals between the first air inlet 14 and the natural gas premixing chamber 17. After the air passes through the second air swirl vanes 19, it forms rotating air, which can be fully mixed with the natural gas.

[0086] Optionally, the inner shell 42 of the combustor is provided with a flow equalization plate, which is located within the mixture distribution chamber 43. Along the axial direction of the inner shell 42 of the combustor, the flow equalization plate is located between the mixture injection hole 46 and the natural gas premixing chamber 17. The flow equalization plate can prevent the mixture from flowing along the outer wall of the inner shell 42 when the flow rate of the mixture is too large, which would lead to uneven mixture entering the natural gas combustion chamber 45 and deteriorate combustion.

[0087] Optionally, the inner wall of the natural gas combustion chamber 45 is provided with a metal fiber mesh. The mixture formed by the mixing of natural gas and air passes sequentially through the mixture injection hole 46 and the metal fiber mesh before entering the natural gas combustion chamber 45. The use of the metal fiber mesh flame stabilizing material can avoid low-load backfire and enable extremely short flame combustion in the natural gas combustion chamber 45.

[0088] Optionally, the air inlet includes a first connecting portion 31, a second connecting portion 32, and a plurality of first air swirl vanes 33. The first connecting portion 31 is fixedly sleeved on the anode exhaust gas inlet 2, and the second connecting portion 32 is fixedly inserted into the premixing inner shell 13. One end of each first air swirl vane 33 is fixedly connected to the first connecting portion 31, and the other end is fixedly connected to the second connecting portion 32. The plurality of first air swirl vanes 33 are spaced apart circumferentially along the first connecting portion 31. The first connecting portion 31 is provided with a plurality of fourth air inlets 34 spaced apart circumferentially. The two ends of each fourth air inlet 34 are respectively connected to an air input pipe and an anode exhaust gas combustion chamber 44. A portion of the air can enter the anode exhaust gas combustion chamber 44 from the fourth air inlets 34, and another portion of the air can enter the anode exhaust gas combustion chamber 44 after being guided by the first air swirl vanes 33, which can make the anode exhaust gas and air fully mixed.

[0089] Optionally, the anode exhaust gas inlet 2 extends into the anode exhaust gas combustion chamber 44. The anode exhaust gas inlet 2 is also provided with anode exhaust gas injection holes 22, which communicate with the anode exhaust gas combustion chamber 44. Anode exhaust gas enters the anode exhaust gas inlet 2 from the anode exhaust gas inlet 21 and enters the anode exhaust gas combustion chamber 44 from the anode exhaust gas injection holes 22. Optionally, there are multiple anode exhaust gas injection holes 22, which are spaced apart along the circumference of the anode exhaust gas inlet 2. The anode exhaust gas is injected radially into the anode exhaust gas combustion chamber 44 along the anode exhaust gas inlet 2, where it undergoes diffusion combustion with air to form a sheet-like flame.

[0090] Optionally, the fuel cell anode exhaust gas burner further includes a burner housing 7, in which a natural gas premix, a first combustor, a catalytic premix 5, and a second combustor 6 are sequentially connected and all located within the burner housing 7. An air distribution chamber 71 is formed between the burner housing 7 and the natural gas premix, the first combustor, the catalytic premix 5, and the second combustor 6. A fifth air inlet 72 is formed between the burner housing 7 and the natural gas premix. The second air inlet 51, the third air inlet 63, and the fifth air inlet 72 are all connected to the air distribution chamber 71. The fifth air inlet 72 is connected to an air input pipe. Air in the air input pipe enters the air distribution chamber 71 through the fifth air inlet 72. Then, a portion of the air enters the catalytic premix chamber through the second air inlet 51, and another portion enters the receiving chamber of the second combustor 6 through the third air inlet 63.

[0091] It is understandable that the first air inlet 14, the air guide, and the fifth air inlet 72 are all located at one end of the burner housing 7 along the axial direction.

[0092] Optionally, a first heat-insulating and fire-resistant layer 8 is fixedly provided on the inner wall of the anode tail gas combustion chamber 44. This can prevent premature ignition of the mixture in the mixture distribution chamber 43 during the combustion process of the anode tail gas and / or natural gas. Optionally, a third heat-insulating and fire-resistant layer (not shown in the figure) is fixedly provided on the inner wall of the natural gas combustion chamber 45.

[0093] Optionally, a second heat-insulating and fire-resistant layer 62 is provided between the inner wall of the receiving cavity and the catalyst carrier 61. The second heat-insulating and fire-resistant layer 62 wraps around the catalyst carrier 61 to prevent the high-temperature catalyst carrier 61 from burning the burner shell 7.

[0094] The present invention also provides a control method for a fuel cell anode exhaust gas burner, employing the above-mentioned fuel cell anode exhaust gas burner, comprising:

[0095] S1: Air is introduced into the fuel cell anode exhaust gas burner. After the fuel cell system starts, the fan starts running, introducing air into the air input pipe of the fuel cell anode exhaust gas burner.

[0096] S2: Natural gas is introduced into the fuel cell anode tail gas burner, and the natural gas combustion chamber 45 is ignited. The natural gas supply valve is opened, and natural gas is introduced into the natural gas inlet 15. The first combustion body is equipped with an igniter channel 9, which can accommodate an igniter. After detecting the natural gas flow rate, the igniter ignites the natural gas combustion chamber 45. The igniter can be an electric spark igniter or a pulse igniter, etc. The igniter ignites at a position on the surface of the metal fiber mesh and within the natural gas combustion chamber 45.

[0097] S3: Perform flame detection on the natural gas combustion chamber 45 to determine if a flame is generated in the natural gas combustion chamber 45; if yes, proceed to S4; if no flame is generated in the natural gas combustion chamber 45, proceed to S31; S31: Stop supplying natural gas to the fuel cell anode tail gas burner and supply air to the fuel cell anode tail gas burner to purge the natural gas combustion chamber 45; S32: Determine if the number of ignition attempts on the natural gas combustion chamber 45 exceeds the set number; if yes, determine that the fuel cell anode tail gas burner is extinguished; if not, return to S2. Specifically, after the igniter ignites for 10 seconds, flame detection is performed. If no flame is generated in the natural gas combustion chamber 45, the natural gas supply valve is closed, air is introduced to purge the first combustion element for 10 seconds, and then natural gas is supplied to the natural gas combustion chamber 45 again and ignited. If ignition fails after 3 consecutive attempts, the fuel cell anode tail gas burner is considered extinguished. Specifically, flame detection can be performed using ultraviolet photoelectric detection or flame ion current detection.

[0098] S4: Adjust the natural gas flow rate based on the gas temperature at the third outlet and the set burner outlet temperature.

[0099] Specifically, it is determined whether the gas temperature at the third outlet is greater than the set burner outlet temperature; if so, the natural gas flow rate is reduced; if not, the natural gas flow rate is increased. After successful ignition of the natural gas combustion chamber 45, natural gas and air undergo fully premixed combustion in the natural gas combustion chamber 45. The natural gas flow rate is adjusted so that the gas temperature at the third outlet is approximately equal to the set burner outlet temperature.

[0100] S5: Detects the air temperature inside the air inlet pipe.

[0101] S6: Determine whether the air temperature in the air input pipe is greater than the set burner inlet air temperature; if yes, proceed to S7; if no, do not supply anode exhaust gas to the fuel cell anode exhaust gas burner. In this embodiment, the burner inlet temperature is set to 400°C.

[0102] S7: Introduce anode exhaust gas into the fuel cell anode exhaust gas burner. Open the anode exhaust gas supply valve to introduce anode exhaust gas into the anode exhaust gas inlet 21 of the anode exhaust gas inlet 2, and the anode exhaust gas enters the anode exhaust gas combustion chamber 44.

[0103] S8: Real-time flame detection is performed on the anode tail gas combustion chamber 44 to determine whether a flame is generated. If so, flame combustion occurs, and S10 is executed; otherwise, S9 is executed. Whether the anode tail gas can burn depends on the content of combustible components in it. When the content of combustible components is high, the anode tail gas undergoes flame combustion within the anode tail gas combustion chamber 44. The gas temperature at the third outlet can be kept constant by adjusting the natural gas flow rate, and the natural gas flame combustion will occur at the tail end of the anode tail gas flame.

[0104] S9: Based on the gas temperature decay rate at the third outlet and the temperature of the catalyst carrier 61, determine whether the fuel cell anode tail gas burner is undergoing stable catalytic combustion; if yes, proceed to S10; if no, determine that the fuel cell anode tail gas burner is shut down.

[0105] Specifically, determine whether the gas temperature decay rate at the third outlet is greater than the set temperature decay rate; if yes, proceed to S91; if no, determine that the fuel cell anode tail gas burner is performing stable catalytic combustion; S91: determine whether the temperature of the catalyst carrier 61 increases within a set time; if yes, determine that the fuel cell anode tail gas burner is performing stable catalytic combustion; if no, determine that the fuel cell anode tail gas burner is not performing stable catalytic combustion.

[0106] When the fuel cell enters a variable composition operating condition where the combustible components of the anode tail gas are reduced due to increased fuel utilization, if the combustible components in the introduced anode tail gas are too low to support combustion, the flame in the first combustion body will be extinguished, and the anode tail gas, natural gas, and air can still undergo stable catalytic combustion within the catalyst carrier 61.

[0107] In this embodiment, the time is set to 60 seconds. Since catalytic combustion involves an ignition process, 60 seconds is set as the ignition time for catalytic combustion. If the temperature of the catalyst support 61 has not risen within 60 seconds, the fuel cell anode exhaust gas burner is considered to be extinguished.

[0108] Understandably, two temperature sensors are installed at the third outlet and at the catalyst support 61, respectively. These sensors can detect the gas temperature at the third outlet and the temperature of the catalyst support 61.

[0109] S10: Adjust the natural gas flow rate based on the gas temperature at the third outlet and the set burner outlet temperature.

[0110] Specifically, determine whether the gas temperature at the third outlet is greater than the set burner outlet temperature; if so, reduce the natural gas flow rate; if not, increase the natural gas flow rate.

[0111] Optionally, between S7 and S8, the process further includes igniting the anode exhaust gas combustion chamber 44. An ignition needle 10 is provided, extending into the anode exhaust gas combustion chamber 44. The anode exhaust gas combustion ignition position and the flame detection position are located within the area surrounding the anode exhaust gas inlet 2. The anode exhaust gas combustion chamber 44 and the natural gas combustion chamber 45 are ignited separately using the ignition needle 10 and an igniter, respectively, which improves the ignition success rate.

[0112] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A fuel cell anode tail gas burner, characterized in that, include: A natural gas premix is ​​provided with a first air inlet (14), a natural gas inlet (15) and a natural gas premixing chamber (17), wherein the first air inlet (14) and the natural gas inlet (15) are both connected to the natural gas premixing chamber (17); An air inlet and an anode tail gas inlet (2), wherein the anode tail gas inlet (2) is fixedly inserted into the air inlet and the air inlet is fixedly inserted into the natural gas premix. The anode tail gas inlet (2) is provided with an anode tail gas inlet (21). The first combustion body is provided with a connected anode tail gas combustion chamber (44), a natural gas combustion chamber (45) and a first gas outlet. The natural gas premix chamber (17) is connected to the natural gas combustion chamber (45). The anode tail gas inlet (2) and the air inlet are both connected to the anode tail gas combustion chamber (44). The catalytic premix (5) is provided with a catalytic premix chamber, a second air inlet (51) and a second gas outlet, and the second air inlet (51), the second gas outlet and the first gas outlet are all connected to the catalytic premix chamber. The second combustion body (6) is provided with a receiving cavity, a third air inlet (63) and a third gas outlet. The receiving cavity contains a catalyst carrier (61). The third air inlet (63), the third gas outlet and the second gas outlet are all connected to the receiving cavity. The air input pipe is connected to the first air inlet (14), the air guide, the second air inlet (51), and the third air inlet (63).

2. The fuel cell anode tail gas burner according to claim 1, characterized in that, The natural gas premix includes a premix outer shell (11), a premix middle shell (12), and a premix inner shell (13). The premix middle shell (12) passes through the premix outer shell (11), and the premix inner shell (13) passes through the premix middle shell (12). The premix outer shell (11) is provided with the natural gas inlet (15). A natural gas distribution cavity (16) is formed between the premix outer shell (11) and the premix middle shell (12). A natural gas premix cavity (17) and the first air inlet (14) are formed between the premix middle shell (12) and the premix inner shell (13). The premix middle shell (12) is provided with a connecting hole (18). The two ends of the connecting hole (18) are respectively connected to the natural gas distribution cavity (16) and the natural gas premix cavity (17).

3. The fuel cell anode tail gas burner according to claim 2, characterized in that, The air inlet includes a first connecting part (31), a second connecting part (32), and a plurality of first air swirl vanes (33). The first connecting part (31) is fixedly sleeved on the anode exhaust gas inlet (2), and the second connecting part (32) is fixedly inserted into the premixed inner shell (13). One end of the first air swirl vane (33) is fixedly connected to the first connecting part (31), and the other end is fixedly connected to the second connecting part (32). The plurality of first air swirl vanes (33) are arranged at intervals along the circumference of the first connecting part (31). The first connecting part (31) is provided with a plurality of fourth air inlets (34) at intervals along its circumference. The two ends of the fourth air inlets (34) are respectively connected to the air input pipe and the anode exhaust gas combustion chamber (44).

4. The fuel cell anode tail gas burner according to claim 2, characterized in that, The first combustor includes a combustor shell (41) and a combustor inner shell (42). The combustor shell (41) is fixedly connected to the premixed body shell (11). A mixed gas distribution chamber (43) is formed between the combustor shell (41) and the combustor inner shell (42). The mixed gas distribution chamber (43) is connected to the natural gas premixed chamber (17). The combustor inner shell (42) is provided with a mixed gas injection hole (46), an anode tail gas combustion chamber (44), and a natural gas combustion chamber (45). The two ends of the mixed gas injection hole (46) are respectively connected to the mixed gas distribution chamber (43) and the natural gas combustion chamber (45).

5. The fuel cell anode tail gas burner according to claim 4, characterized in that, A plurality of second air swirl vanes (19) are provided between the first air inlet (14) and the natural gas premixing chamber (17); or, a plurality of second air swirl vanes (19) are provided between the natural gas premixing chamber (17) and the mixed gas distribution chamber (43).

6. The fuel cell anode tail gas burner according to claim 4, characterized in that, The combustion chamber (42) is provided with a flow equalization plate, which is located in the gas mixture distribution chamber (43).

7. The fuel cell anode tail gas burner according to any one of claims 1-6, characterized in that, The inner wall of the natural gas combustion chamber (45) is provided with a metal fiber mesh.

8. The fuel cell anode tail gas burner according to any one of claims 1-6, characterized in that, The anode exhaust gas inlet (2) extends into the anode exhaust gas combustion chamber (44), and the anode exhaust gas inlet (2) is also provided with an anode exhaust gas injection hole (22), which is connected to the anode exhaust gas combustion chamber (44).

9. The fuel cell anode tail gas burner according to any one of claims 1-6, characterized in that, The fuel cell anode tail gas burner also includes a burner housing (7). The natural gas premix, the first burner, the catalytic premix (5), and the second burner (6) are connected in sequence and are all located inside the burner housing (7). An air distribution cavity (71) is formed between the burner housing (7) and the natural gas premix, the first burner, the catalytic premix (5), and the second burner (6). A fifth air inlet (72) is formed between the burner housing (7) and the natural gas premix. The second air inlet (51), the third air inlet (63), and the fifth air inlet (72) are all connected to the air distribution cavity (71). The fifth air inlet (72) is connected to the air input pipe.

10. The fuel cell anode tail gas burner according to any one of claims 1-6, characterized in that, The inner wall of the anode tail gas combustion chamber (44) is fixedly provided with a first heat insulation and fire-resistant layer (8).

11. The fuel cell anode tail gas burner according to any one of claims 1-6, characterized in that, A second heat-insulating and fire-resistant layer (62) is provided between the inner wall of the accommodating cavity and the catalyst carrier (61).

12. A control method for a fuel cell anode tail gas burner, characterized in that, The fuel cell anode exhaust gas burner according to any one of claims 1-11 comprises: S1: Introduce air into the fuel cell anode exhaust gas burner; S2: Natural gas is introduced into the fuel cell anode tail gas burner and the natural gas combustion chamber (45) is ignited; S3: Perform flame detection on the natural gas combustion chamber (45) to determine whether the natural gas combustion chamber (45) produces a flame; If so, proceed to S4; S4: Adjust the natural gas flow rate based on the gas temperature at the third outlet and the set burner outlet temperature; S5: Detects the air temperature inside the air inlet pipe; S6: Determine whether the air temperature in the air input pipe is greater than the set burner inlet air temperature; If so, proceed to S7; S7: Introduce anode exhaust gas into the fuel cell anode exhaust gas burner; S8: Real-time flame detection of the anode exhaust gas combustion chamber (44) to determine whether the anode exhaust gas combustion chamber (44) produces a flame; If so, then proceed with flame combustion and S10; If not, proceed to S9; S9: Determine whether the fuel cell anode tail gas burner is performing stable catalytic combustion based on the gas temperature decay rate at the third outlet and the temperature of the catalyst support (61); If so, proceed to S10; If not, the fuel cell anode exhaust gas burner will shut down; S10: Adjust the natural gas flow rate based on the gas temperature at the third outlet and the set burner outlet temperature.

13. The control method for the fuel cell anode tail gas burner according to claim 12, characterized in that, Determining whether the fuel cell anode tail gas burner is undergoing stable catalytic combustion based on the gas temperature decay rate at the third outlet and the temperature of the catalyst support (61) includes: Determine whether the gas temperature decay rate at the third outlet is greater than the set temperature decay rate; If so, then proceed to S91; If not, the fuel cell anode exhaust gas burner performs stable catalytic combustion; S91: Determine whether the temperature of the catalyst support (61) increases within a set time period; If so, the fuel cell anode exhaust gas burner will perform stable catalytic combustion; If not, then the fuel cell anode exhaust combustor is not undergoing stable catalytic combustion.

14. The control method for the fuel cell anode tail gas burner according to claim 12, characterized in that, In S3, if no flame is generated in the natural gas combustion chamber (45), then proceed to S31; S31: Stop supplying natural gas to the fuel cell anode tail gas burner and supply air to the fuel cell anode tail gas burner to purge the natural gas combustion chamber (45); S32: Determine whether the number of ignitions of the natural gas combustion chamber (45) is greater than the set number; If so, the fuel cell anode exhaust gas burner will shut down; If not, return to S2.

15. The control method for the fuel cell anode tail gas burner according to claim 12, characterized in that, Adjusting the natural gas flow rate based on the gas temperature at the third outlet and the set burner outlet temperature includes: Determine whether the gas temperature at the third outlet is greater than the set burner outlet temperature; If so, reduce the natural gas flow rate; If not, increase the natural gas flow rate.

16. The control method for the fuel cell anode tail gas burner according to claim 12, characterized in that, Between S7 and S8, there is also: ignition of the anode exhaust gas combustion chamber (44).

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