Anti-backflow and hydrogen re-separation mixed exhaust for fuel cell

Abstract

The utility model provides an anti-backflow and hydrogen re-separation mixed tail exhaust of a fuel cell. The anti-backflow and hydrogen re-separation mixed tail exhaust comprises a cathode tail exhaust pipe, a first Tesla valve, a second Tesla valve and a hydrogen-water separation membrane assembly, the fuel cell anti-backflow and hydrogen re-separation mixed tail exhaust can separate a mixture discharged from an anode, and recycle the separated hydrogen, so that the utilization efficiency of the hydrogen is improved, meanwhile, the gas backflow phenomenon can be prevented, and the stability of a fuel cell stack is improved. The discharge pipeline is simple in structure and convenient to process and mount, the integration level of the discharge pipeline is improved, the mounting space is saved, a cathode tail gas mixture, a mixture obtained after anode tail gas separation, electric pile blowing tail gas and ejector pressure release valve outlet gas are fully mixed in a mixing area and then discharged, and the discharge efficiency is improved. The hydrogen concentration of the tail gas of the fuel cell can be reduced, and the cost and the installation space for diluting the tail gas are reduced.

Description

Technical Field

[0001] This utility model relates to the field of fuel cell technology, and in particular to a fuel cell backflow prevention and hydrogen re-separation mixed tailpipe. Background Technology

[0002] The use of traditional fossil fuels poses a serious problem of carbon dioxide emissions, and green, low-carbon, and sustainable development has become a global consensus. Hydrogen energy has advantages such as being clean, storable, safe, and highly controllable, and has a wide range of applications. Hydrogen fuel cell systems can generate electricity from hydrogen through a chemical reaction, and also have advantages such as high fuel energy conversion efficiency, low noise, and zero emissions. Therefore, fuel cell systems are an important component of hydrogen energy applications.

[0003] As a crucial component of fuel cells, the fuel cell stack's safe, stable, and efficient operation has a critical impact on the system. The efficient, stable, and safe operation of a fuel cell system requires favorable preconditions. The insulation of the fuel cell is affected by the sealing during the core assembly process. Furthermore, there is a risk of backflow of the mixed gas due to cathode venting. Therefore, purging and backflow prevention of the stack housing are of paramount importance. Simultaneously, the periodic anode venting of fuel cells leads to the waste of some hydrogen. Therefore, improving hydrogen utilization and preventing tail gas backflow are of great significance for the efficient, stable, and safe operation of the fuel cell system.

[0004] Patent application CN116093376A discloses a hydrogen path system for a fuel cell stack, including a fuel cell stack, a mixing device, a hydrogen injector, a reflux device, and a Tesla valve. The fuel cell stack has a hydrogen inlet and a hydrogen outlet at both ends. The hydrogen inlet, reflux device, Tesla valve, mixing device, and hydrogen outlet are connected sequentially via pipelines. The mixing device is connected to the hydrogen injector via a pipeline. The hydrogen injector is used to replenish the fuel cell stack with the required dry hydrogen and maintain the required pressure. The Tesla valve is used to introduce wet hydrogen discharged from the reflux device into the mixing device, which mixes the dry and wet hydrogen. Compared with existing technologies, replacing solenoid valves or check valves with Tesla valves reduces electrical control or mechanical movement structures, improving system stability. Adding a mixing device to the hydrogen path ensures thorough mixing of the incoming gas, improving the stack's stability and lifespan.

[0005] However, the above solution is only a separation and circulation system for the anode tailpipes. The integration of each discharge pipeline is relatively low, and the separate arrangement will take up space.

[0006] Therefore, there is an urgent need to provide a fuel cell backflow prevention and hydrogen re-separation mixed tail exhaust to solve the above-mentioned technical problems. Utility Model Content

[0007] To address the aforementioned technical problems in the existing technology, this utility model provides a fuel cell backflow prevention and hydrogen re-separation mixed tailpipe solution, which can improve hydrogen utilization, prevent tailpipe backflow, enhance stack stability, increase structural integration, and save installation space.

[0008] This utility model provides a fuel cell backflow prevention and hydrogen reseparation mixing tailpipe, including a cathode tailpipe, a first Tesla valve, a second Tesla valve, and a hydrogen-water separation membrane assembly.

[0009] One end of the cathode tailpipe has a cathode tailpipe inlet connector, and the other end has a mixed gas outlet. The inner cavity of the cathode tailpipe has a mixing zone near the mixed gas outlet. The cathode tailpipe is also provided with an anode tailpipe mixing inlet and a fuel cell purge tail gas mixing inlet that connect to the mixing zone.

[0010] The first Tesla valve has a first valve inlet and a first valve outlet, the first valve outlet being connected to the anode tail discharge mixing inlet.

[0011] The second Tesla valve has a second valve inlet and a second valve outlet, the second valve outlet being connected to the fuel cell stack purge exhaust gas mixing inlet.

[0012] The hydrogen-water separation membrane assembly has a hydrogen separation membrane core inside its cavity for separating hydrogen gas. The assembly includes an anode tail gas inlet, a hydrogen separation membrane outlet, and an anode tail gas residual outlet, which is connected to the inlet of the first valve. The hydrogen separation membrane core is composed of a polymer film and utilizes the difference in permeation rate caused by the difference in the solubility and diffusion coefficients of gases in the polymer to separate the gases.

[0013] During installation, the cathode tail gas inlet connector is connected to the cathode tail gas outlet of the fuel cell stack; the second valve inlet is connected to the purge tail gas outlet of the fuel cell stack; the anode tail gas inlet connector is connected to the anode tail gas outlet of the fuel cell stack; and the hydrogen separation membrane outlet is connected to the ejector inlet of the ejector used to introduce hydrogen into the fuel cell stack.

[0014] The hydrogen-water separation membrane assembly separates the mixture formed by the residual hydrogen gas from the anode reaction, the product liquid water and water vapor, and a small amount of nitrogen impurities that do not participate in the reaction. The purified hydrogen gas is then guided to the ejector inlet for reuse. The remaining mixture after hydrogen removal is guided into the first Tesla valve, and then discharged through the anode tail discharge mixing inlet into the mixing zone of the cathode tail discharge pipe. The first Tesla valve, due to its structural characteristics, ensures unidirectional fluid flow, preventing the remaining mixture after hydrogen removal from flowing back in.

[0015] Additionally, the fuel cell purge exhaust gas enters the mixing zone of the cathode tailpipe through the second Tesla valve for discharge. Similarly, the special structure of the second Tesla valve prevents the exhaust gas from flowing back into the fuel cell purge exhaust gas outlet due to the increased gas pressure in the cathode tailpipe caused by anode exhaust.

[0016] Furthermore, the cathode tailpipe increases in diameter in the mixing zone to form a stepped structure, and the anode tailpipe mixing inlet and the fuel cell purge exhaust gas mixing inlet are located on the stepped surface of the stepped structure.

[0017] Furthermore, the first Tesla valve and the second Tesla valve are fixed on the outer wall of the cathode tailpipe.

[0018] Furthermore, the outer wall of the cathode tailpipe is provided with a mounting surface for fixing the first Tesla valve and the second Tesla valve.

[0019] Furthermore, the cathode tailpipe has a split-type cap at one end of the mixed gas outlet, and the mixed gas outlet is located on the cap;

[0020] The side wall of the cathode tailpipe has an outwardly extending mounting ring, and the cover is fixedly connected to the mounting ring by bolts.

[0021] Furthermore, the cover has a sealing portion that extends into the inner cavity of the cathode tailpipe, and a sealing groove is provided on the outer wall of the sealing portion, with a sealing ring provided inside the sealing groove.

[0022] Furthermore, the cathode tailpipe is also provided with a pressure relief inlet connector that connects to the mixing zone. During installation, the pressure relief inlet connector is connected to the pressure relief valve outlet of the ejector used to supply hydrogen to the fuel cell stack.

[0023] The beneficial effects of this utility model are as follows:

[0024] (1) The fuel cell anti-backflow and hydrogen re-separation mixed tail exhaust can separate the mixture discharged from the anode, and recycle the separated hydrogen, thereby improving the utilization efficiency of hydrogen. At the same time, it can prevent the gas backflow phenomenon and improve the stability of the fuel cell stack.

[0025] (2) The fuel cell anti-backflow and hydrogen reseparation mixing tail structure is simple, easy to process and install, and improves the integration of the emission pipeline, saving installation space.

[0026] (3) The fuel cell backflow prevention and hydrogen reseparation mixing tail exhaust mixes the cathode tail exhaust gas mixture, the anode tail exhaust gas mixture after separation, the stack purge tail gas and the ejector pressure relief valve outlet gas in the mixing zone before discharge, which can reduce the hydrogen concentration of the fuel cell tail exhaust gas and reduce the cost and installation space of tail exhaust hydrogen dilution. Attached Figure Description

[0027] Figure 1 This is a front view schematic diagram of the fuel cell anti-backflow and hydrogen re-separation mixing tailpipe of this utility model.

[0028] Figure 2 This is a three-dimensional structural diagram of the fuel cell anti-backflow and hydrogen re-separation mixing tailpipe of this utility model.

[0029] Figure 3 This is a top view schematic diagram of the fuel cell anti-backflow and hydrogen re-separation mixing tailpipe structure of this utility model.

[0030] Figure 4 for Figure 3 A cross-sectional view along the AA direction.

[0031] Figure 5 This is a three-dimensional structural diagram of the hydrogen-water separation membrane assembly.

[0032] Figure 6 This is a bottom view of the hydrogen-water separation membrane assembly.

[0033] Figure 7 for Figure 6 A cross-sectional view along the BB direction.

[0034] Figure 8 This is a schematic diagram of half of the structure of the first or second Tesla valve contacting the outer wall of the cathode tailpipe.

[0035] Figure 9 This is a schematic diagram of the three-dimensional structure of the cathode tailpipe.

[0036] Figure label:

[0037] 1. Cathode tailpipe; 11. Cathode tailpipe inlet connector; 12. Mixed gas outlet; 13. Mixing zone; 14. Anode tailpipe mixing inlet; 15. Fuel cell purge exhaust gas mixing inlet; 16. Cover; 161. Sealing part; 162. Sealing groove; 163. Sealing ring; 17. Mounting ring; 18. Pressure relief inlet connector.

[0038] First Tesla valve 2, first valve inlet 21, first valve outlet 22

[0039] Second Tesla valve 3, second valve inlet 31, second valve outlet 32.

[0040] 4. Hydrogen-water separation membrane assembly; 41. Hydrogen separation membrane core; 42. Anode tail exhaust inlet connector; 43. Hydrogen separation membrane outlet; 44. Anode tail exhaust residual gas outlet. Detailed Implementation

[0041] like Figure 1-9 As shown, this utility model provides a fuel cell backflow prevention and hydrogen reseparation mixing tailpipe, including a cathode tailpipe 1, a first Tesla valve 2, a second Tesla valve 3, and a hydrogen-water separation membrane assembly 4.

[0042] like Figure 1-4 As shown, one end of the cathode tailpipe 1 has a cathode tailpipe inlet connector 11, and the other end has a mixed gas outlet 12. The inner cavity of the cathode tailpipe 1 has a mixing zone 13 at the end near the mixed gas outlet 12. The cathode tailpipe 1 is also provided with an anode tailpipe mixing inlet 14 and a fuel cell purge tail gas mixing inlet 15 that are connected to the mixing zone 13.

[0043] The diameter of the cathode tailpipe 1 increases in the mixing zone 13 to form a stepped structure, and the anode tailpipe mixing inlet 14 and the fuel cell purging tail gas mixing inlet 15 are located on the stepped surface of the stepped structure.

[0044] The cathode tailpipe 1 has a separate cover 16 at one end of the mixed gas outlet 12, and the mixed gas outlet 12 is located on the cover 16.

[0045] The side wall of the cathode tail tube 1 has an outwardly extending mounting ring 17, and the cover 16 is fixedly connected to the mounting ring 17 by bolts.

[0046] The cover 16 has a sealing part 161 that extends into the inner cavity of the cathode tail tube 1. A sealing groove 162 is provided on the outer wall of the sealing part 161, and a sealing ring 163 is provided in the sealing groove 162.

[0047] The outer wall of the cathode tailpipe 1 is provided with a mounting surface for fixing the first Tesla valve 2 and the second Tesla valve 3.

[0048] The first Tesla valve 2 has a first valve inlet 21 and a first valve outlet 22, the first valve outlet 22 being connected to the anode tail mix inlet 14.

[0049] The second Tesla valve 3 has a second valve inlet 31 and a second valve outlet 32, and the second valve outlet 32 ​​is connected to the fuel cell stack purge exhaust gas mixing inlet 15.

[0050] like Figure 2 and Figure 9 As shown, the cathode tailpipe 1 is also provided with a pressure relief inlet connector 18 that connects to the mixing zone 13. During installation, the pressure relief inlet connector 18 is connected to the pressure relief valve outlet of the ejector used to supply hydrogen to the fuel cell stack.

[0051] like Figure 4-7As shown, the hydrogen-water separation membrane assembly 4 has a hydrogen separation membrane core 41 inside its cavity for separating hydrogen gas. The hydrogen-water separation membrane assembly 4 has an anode tail gas inlet 42, a hydrogen separation membrane outlet 43, and an anode tail gas residual outlet 44, which is connected to the first valve inlet 21. The hydrogen separation membrane core 41 is composed of a polymer film and utilizes the difference in permeation rate caused by the difference in the solubility and diffusion coefficients of gases in the polymer to separate the gases.

[0052] During installation, the cathode tail gas inlet connector 11 is connected to the cathode tail gas outlet of the fuel cell stack; the second valve inlet 31 is connected to the purge tail gas outlet of the fuel cell stack; the anode tail gas inlet connector 42 is connected to the anode tail gas outlet of the fuel cell stack; and the hydrogen separation membrane outlet 43 is connected to the ejector inlet of the ejector used to introduce hydrogen into the fuel cell stack.

[0053] In practical applications, the cathode-side exhaust gas enters the cathode exhaust pipe 1 through the cathode exhaust inlet 11 and is discharged, while the anode-side exhaust gas enters the hydrogen-water separation membrane assembly 4 through the anode exhaust inlet 42. When the anode-side exhaust gas passes through the hydrogen separation membrane core 41, hydrogen, nitrogen, and water separate in this region due to the different permeabilities of the components. Hydrogen permeates through the hydrogen separation membrane core 41 and enters the ejector through the hydrogen separation membrane outlet 43, thus re-entering the fuel cell stack. The remaining mixture that has not permeated through the hydrogen separation membrane core 41 enters the first Tesla valve 2 through the anode exhaust residual gas outlet 44, and then enters the mixing zone 13 of the cathode exhaust pipe 1 through the anode exhaust mixing inlet 14 for discharge. The first Tesla valve 2, due to its structural characteristics, ensures unidirectional fluid flow, preventing the remaining mixture after hydrogen removal from flowing back in. Figure 8 As shown.

[0054] During fuel cell stack purging, the purging exhaust gas enters the mixing zone 13 of the cathode tailpipe 1 through the second Tesla valve 3 and is then discharged. Similarly, the special structure of the second Tesla valve 3 is used to prevent the exhaust gas from flowing back into the fuel cell stack purging exhaust gas outlet due to the gas pressure increase in the cathode tailpipe 1 caused by anode exhaust.

[0055] Ultimately, the cathode exhaust gas mixture, the anode exhaust gas mixture after separation, the stack purge exhaust gas, and the ejector pressure relief valve outlet gas are fully mixed in the mixing zone 13 before being discharged, which can reduce the hydrogen concentration in the fuel cell exhaust gas.

Claims

1. A fuel cell backflow prevention and hydrogen re-separation mixed tailpipe, characterized in that, include: The cathode tailpipe has a cathode tailpipe inlet connector at one end and a mixed gas outlet at the other end. The inner cavity of the cathode tailpipe has a mixing zone near the mixed gas outlet. The cathode tailpipe is also provided with an anode tailpipe mixing inlet and a fuel cell purge tail gas mixing inlet that communicate with the mixing zone. A first Tesla valve has a first valve inlet and a first valve outlet, the first valve outlet being connected to the anode tail discharge mixing inlet; The second Tesla valve has a second valve inlet and a second valve outlet, the second valve outlet being connected to the fuel cell stack purge exhaust gas mixing inlet; A hydrogen-water separation membrane assembly has a hydrogen separation membrane core in its inner cavity for separating hydrogen gas. The hydrogen-water separation membrane assembly has an anode tail gas inlet, a hydrogen separation membrane outlet, and an anode tail gas residual gas outlet. The anode tail gas residual gas outlet is connected to the inlet of the first valve. During installation, the cathode tail gas inlet connector is connected to the cathode tail gas outlet of the fuel cell stack; the second valve inlet is connected to the purge tail gas outlet of the fuel cell stack; the anode tail gas inlet connector is connected to the anode tail gas outlet of the fuel cell stack; and the hydrogen separation membrane outlet is connected to the ejector inlet of the ejector used to introduce hydrogen into the fuel cell stack.

2. The fuel cell backflow prevention and hydrogen re-separation mixed tailpipe according to claim 1, characterized in that, The cathode tailpipe increases in diameter in the mixing zone to form a stepped structure, and the anode tailpipe mixing inlet and the fuel cell purge exhaust gas mixing inlet are located on the stepped surface of the stepped structure. The first Tesla valve and the second Tesla valve are fixed on the outer wall of the cathode tailpipe.

3. The fuel cell backflow prevention and hydrogen re-separation mixing tailpipe according to claim 2, characterized in that, The outer wall of the cathode tailpipe is provided with a mounting surface for fixing the first Tesla valve and the second Tesla valve.

4. The fuel cell backflow prevention and hydrogen re-separation mixed tailpipe according to claim 1, characterized in that, The cathode tailpipe has a split-type cap at one end of the mixed gas outlet, and the mixed gas outlet is located on the cap; The side wall of the cathode tailpipe has an outwardly extending mounting ring, and the cover is fixedly connected to the mounting ring by bolts.

5. The fuel cell backflow prevention and hydrogen re-separation mixing tailpipe according to claim 4, characterized in that, The cover has a sealing part that extends into the inner cavity of the cathode tailpipe, and a sealing groove is provided on the outer wall of the sealing part, and a sealing ring is provided in the sealing groove.

6. The fuel cell backflow prevention and hydrogen re-separation mixed tailpipe according to claim 1, characterized in that, The cathode tailpipe is also provided with a pressure relief inlet connector that connects to the mixing zone. During installation, the pressure relief inlet connector is connected to the pressure relief valve outlet of the ejector used to introduce hydrogen into the fuel cell stack.

Images