A tail gas emission device and method for a hydrogen fuel cell engine

Abstract

The present invention provides an exhaust gas emission device and method for a hydrogen fuel cell engine, which relates to the field of hydrogen fuel cells and comprises an outer shell, an exhaust gas separation mechanism, a hydrogen recovery mechanism, a hydrogen auxiliary emission mechanism, a support mechanism and a drain pipe, wherein the hydrogen recovery mechanism is located above the exhaust gas separation mechanism, and the hydrogen recovery mechanism and the exhaust gas separation mechanism are both fixed to the inside of the outer shell by a support mechanism, and the bottom of the outer shell is connected with a drain pipe; the present invention connects the exhaust gas inlet pipe with the stack discharge port of the hydrogen fuel cell, thereby sending the exhaust gas into the outer cylinder, at which time the hydrogen rises, and water is sent into the drain pipe through the through hole on the bottom plate, and the hydrogen passes through a separation element during the rising process to further separate the water adsorbed on the hydrogen, and after the separation during the rising process, the hydrogen is sent to the hydrogen side of the hydrogen fuel cell stack by the hydrogen recovery mechanism for recycling, thereby greatly increasing the use efficiency of the hydrogen.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen fuel cells, and in particular to an exhaust gas emission device and method of a hydrogen fuel cell engine. Background Art

[0002] Hydrogen fuel cells are power generation devices that convert chemical energy in fuel and oxidant directly into electrical energy through electrochemical reactions. They have the advantages of high energy conversion efficiency, high energy density, low vibration and noise, and zero emissions. Therefore, hydrogen fuel cells are regarded as the ideal clean and efficient power device in the 21st century. They are an important way to solve the two major problems of resource scarcity and pollution deterioration. They have broad development and application prospects in the fields of new energy vehicles and green ships.

[0003] It is inevitable that a fuel cell stack will leak a small amount of hydrogen to the outside world. The accumulation of hydrogen may cause dangers such as fire and explosion. Most existing technical solutions are to encapsulate the stack in a protective cover and use forced ventilation to dilute and release the hydrogen in the protective cover. During the reaction of the stack, hydrogen also needs to be discharged to a certain extent to take out the inert gas and water in the hydrogen. At the same time, some water will also be generated on the hydrogen side of the stack. After separation by the gas-water separator, it needs to be discharged to the outside world. The residual air after the electrochemical reaction on the air side of the stack also needs to be discharged;

[0004] The "Exhaust Emission Device for a Hydrogen Fuel Cell Engine" (Application No. 202110910027.4) applied by the Wuhan Marine Electric Propulsion Device Research Institute proposes an exhaust emission structure. The structure adopts the principle of an ejector pump to achieve unpowered negative pressure ventilation to purge the leaked hydrogen from the fuel cell stack, and then cooperates with a three-way catalytic converter to completely eliminate the leaked hydrogen. Although this structure achieves the purpose of completely eliminating hydrogen, leakage is inevitable, which leads to an increase in the overall energy consumption of the hydrogen fuel cell engine and increases its use cost. Therefore, the present invention proposes an exhaust emission device for a hydrogen fuel cell engine and a method thereof to solve the problems existing in the prior art. Summary of the invention

[0005] In view of the above problems, the present invention proposes an exhaust gas emission device and method for a hydrogen fuel cell engine. The exhaust gas emission device for the hydrogen fuel cell engine connects the exhaust gas inlet pipe with the exhaust port of the hydrogen fuel cell stack, thereby sending the exhaust gas into the outer cylinder. At this time, the hydrogen rises, and the water is sent into the drain pipe through the through hole on the bottom plate. During the rising process of the hydrogen, the water adsorbed on the hydrogen is further separated by the separation element. After the separation during the rising process, the hydrogen is sent to the hydrogen side of the hydrogen fuel cell stack by the hydrogen recovery mechanism for recycling, which greatly increases the utilization efficiency of the hydrogen.

[0006] To achieve the purpose of the present invention, the present invention is implemented through the following technical solutions: an exhaust gas emission device for a hydrogen fuel cell engine, comprising an outer shell, an exhaust gas separation mechanism, a hydrogen recovery mechanism, a hydrogen auxiliary emission mechanism, a support mechanism and a drain pipe, wherein the hydrogen recovery mechanism is located above the exhaust gas separation mechanism, and the hydrogen recovery mechanism and the exhaust gas separation mechanism are both fixed inside the outer shell through the support mechanism, the bottom of the outer shell is connected to the drain pipe, and the discharge end of the drain pipe is provided with a dilution mechanism for diluting hydrogen;

[0007] The tail gas separation mechanism comprises an outer cylinder, a top plate, a bottom plate, a fixed shaft and a separator, wherein the top of the outer cylinder is provided with a top plate, the top plate is connected to the hydrogen recovery mechanism, the bottom of the outer cylinder is provided with a bottom plate, a plurality of through holes are provided on the bottom plate, a fixed shaft is connected at the center of the top plate and the bottom plate, a separator for assisting the separation of cleaning and water is spirally wound on the fixed shaft, a tail gas inlet pipe is provided on the outer cylinder on one side of the lower end of the separator, and the other end of the tail gas inlet pipe passes through the outer shell and is connected to the exhaust end of the fuel cell stack;

[0008] A hydrogen auxiliary discharge mechanism is provided on one side of the bottom of the top plate, and a discharge end of the hydrogen auxiliary discharge mechanism is connected to the dilution mechanism after passing through the outer cylinder and the outer shell through an exhaust pipe.

[0009] A further improvement is that a liquid collecting tray is provided below the bottom plate, the outer wall of the liquid collecting tray is fixedly connected to the inner wall of the outer cylinder, the liquid collecting tray is funnel-shaped, a sealing block is provided in the drain pipe at a position in front of the dilution mechanism, and a gap is provided between the sealing block and the bottom inner wall of the drain pipe for liquid to flow through.

[0010] A further improvement is that a plurality of separation strips are evenly spaced on the surface of the separation piece, and the interfaces of the separation strips are rectangular.

[0011] A further improvement is that the hydrogen recovery mechanism includes a hydrogen circulation pump and a hydrogen return pipe, the hydrogen circulation pump is located above the top plate, a hydrogen return pipe is provided on one side of the hydrogen circulation pump, one end of the hydrogen return pipe passes through the outer cylinder and the outer shell and is connected to the hydrogen side of the fuel cell stack, and a connecting assembly is provided between the hydrogen circulation pump and the outer cylinder.

[0012] A further improvement is that the connecting assembly includes a main connecting pipe and an auxiliary connecting pipe, the upper end of the main connecting pipe is connected to the hydrogen circulation pump, and three groups of auxiliary connecting pipes are provided on the outer wall of the lower end of the main connecting pipe, and the lower ends of the three groups of auxiliary connecting pipes all pass through the top plate and are inserted into the outer cylinder.

[0013] Further improvements are: the hydrogen-assisted emission mechanism includes a cavity seat, a balloon, a gas rod, a reset member, a discharge pipe and a connecting hole, the cavity seat is fixed to the bottom of the top plate, the top plate is provided with a balloon at a position directly above the cavity seat, the balloon is connected to the air cavity inside the cavity seat through the gas rod, the air cavity of the cavity seat is provided with a reset member, the outer end of the reset member is exposed inside the outer tube, the bottom of the cavity seat is provided with a discharge pipe, the lower part of the reset member is provided with a connecting hole connected to the discharge pipe, and the cavity seat is located at the exposed end of the reset member. There are multiple groups of limit plates distributed in a ring array for limiting the reset member.

[0014] A further improvement is that the dilution mechanism includes a hydrogen delivery pipe, a hydrogen discharge seat, an air collecting seat, an air delivery pipe and an air discharge seat, the hydrogen delivery pipe is located inside the drain pipe, one end of the hydrogen delivery pipe is connected to the exhaust pipe, the other end of the hydrogen delivery pipe is connected to the hydrogen discharge seat, the output end of the hydrogen discharge seat faces upward, an air collecting seat is provided at the bottom of the drain pipe, one end of the air collecting seat is provided with an air delivery pipe, one end of the air delivery pipe is connected to the air discharge seat, the air discharge seat is located directly above the hydrogen discharge seat, and the output end of the air discharge seat faces the output end of the hydrogen discharge seat.

[0015] A further improvement is that the support mechanism includes a support rod, and the support rods are symmetrically arranged on the outer wall of the hydrogen circulation pump and the outer cylinder, and one end of the support rod is fixedly connected to the inner wall of the outer shell.

[0016] A further improvement is that a liquid recovery hole is provided at the bottom of the drain pipe near the output end, a filter bin is provided on the outer wall of the bottom of the drain pipe below the liquid recovery hole, and a recovery connecting pipe port is provided at the lower end of the filter bin.

[0017] Using the above tail gas emission device, the emission method includes the following steps:

[0018] S1. When the stack is tail-discharging, the tail gas is sent into the tail gas separation mechanism through the tail gas inlet pipe. Since the tail gas includes hydrogen and water, the hydrogen rises in the tail gas separation mechanism, and the water is discharged through the through holes on the bottom plate. The rising hydrogen is then sent to the hydrogen side of the stack through the hydrogen circulation pump.

[0019] S2, at the same time, the separated water in the tail drain is sent to the liquid collecting tray through the through hole, and at the same time, a blocking block is arranged inside the drain pipe to limit the water discharge rate, so that the water discharge rate is less than the separation rate of the water in the tail drain, so that the water can be collected in the liquid collecting tray, thereby forming a water seal, preventing hydrogen from leaking from the drain pipe, and further increasing the recovery rate of hydrogen;

[0020] S3. When the hydrogen circulation pump fails, the hydrogen in the tail exhaust can no longer be recovered. At this time, as the hydrogen concentration inside the outer cylinder increases, when the hydrogen completely fills the separation space inside the outer cylinder, the hydrogen pushes the reset member to move in cooperation with the water seal at the bottom. As the reset member moves, the connecting hole opens, thereby discharging excess hydrogen from the discharge pipe. The air discharged from the discharge pipe sends the hydrogen into the drain pipe through the exhaust pipe and is discharged through the hydrogen discharge seat, while the air discharge seat opposite to the hydrogen discharge seat discharges air, thereby diluting the hydrogen. Finally, the diluted air is discharged from the drain pipe;

[0021] S4. The volume of air discharged from the air discharge seat should be greater than the volume of hydrogen discharged from the hydrogen discharge seat, so as to fully dilute the hydrogen. At the same time, considering the rise of hydrogen, the hydrogen discharge seat is located below the air discharge seat, so as to form gas convection and further increase the dilution effect of hydrogen.

[0022] S5. When the tail water is discharged, it is collected through a liquid recovery pipe, filtered through a filter chamber, and then connected to the cooling mechanism of the automobile through a recovery connection pipe port, so that the tail water is recycled.

[0023] The beneficial effects of the present invention are as follows: the present invention connects the exhaust gas inlet pipe with the exhaust port of the hydrogen fuel cell stack, thereby sending the exhaust gas into the outer cylinder. At this time, the hydrogen rises, and the water is sent into the discharge pipe through the through hole on the bottom plate. In the process of the rising of the hydrogen, the hydrogen passes through the separation element to further separate the water adsorbed on the hydrogen. After the separation in the rising process, the hydrogen is sent to the hydrogen side of the hydrogen fuel cell stack by the hydrogen recovery mechanism for recycling, which greatly increases the utilization efficiency of the hydrogen and reduces the use cost. The device is also provided with a hydrogen auxiliary emission mechanism and a dilution mechanism. When the hydrogen recovery mechanism fails, the hydrogen is auxiliary-emitted by the hydrogen auxiliary emission mechanism and then diluted by the dilution mechanism, which greatly increases the safety performance of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the present invention.

[0025] Figure 2 It is a cross-sectional schematic diagram of the dilution mechanism of the present invention.

[0026] Figure 3 It is a schematic cross-sectional view of the tail gas separation mechanism of the present invention.

[0027] Figure 4 It is a schematic diagram of the hydrogen-assisted emission mechanism of the present invention.

[0028] Figure 5 It is a cross-sectional schematic diagram of the hydrogen-assisted emission mechanism of the present invention.

[0029] Among them: 1. outer shell; 2. drain pipe; 3. outer cylinder; 4. top plate; 5. bottom plate; 6. fixed axis; 7. separator; 8. exhaust gas inlet pipe; 9. liquid collecting tray; 10. sealing block; 11. separator strip; 12. hydrogen circulation pump; 13. hydrogen return pipe; 14. main connecting pipe; 15. auxiliary connecting pipe; 16. cavity seat; 17. balloon; 18. gas rod; 19. reset part; 20. discharge pipe; 21. connecting hole; 22. hydrogen delivery pipe; 23. hydrogen discharge seat; 24. air collection seat; 25. air delivery pipe; 26. air discharge seat; 27. exhaust pipe; 28. support rod; 29. ​​liquid recovery hole; 30. filter bin; 31. recovery connection pipe mouth; 32. limit plate. DETAILED DESCRIPTION

[0030] In order to deepen the understanding of the present invention, the present invention will be further described in detail below in conjunction with examples. The examples are only used to explain the present invention and do not constitute a limitation on the protection scope of the present invention.

[0031] according to Figure 1-5 As shown, this embodiment proposes an exhaust gas emission device for a hydrogen fuel cell engine, comprising an outer shell 1, an exhaust gas separation mechanism, a hydrogen recovery mechanism, a hydrogen auxiliary emission mechanism, a support mechanism and a drain pipe 2, wherein the hydrogen recovery mechanism is located above the exhaust gas separation mechanism, and the hydrogen recovery mechanism and the exhaust gas separation mechanism are both fixed to the inside of the outer shell 1 through the support mechanism, and the bottom of the outer shell 1 is connected to the drain pipe 2, and the discharge end of the drain pipe 2 is provided with a dilution mechanism for diluting hydrogen;

[0032] The tail gas separation mechanism comprises an outer cylinder 3, a top plate 4, a bottom plate 5, a fixed shaft 6 and a separator 7. The top of the outer cylinder 3 is provided with a top plate 4, and the top plate 4 is connected to the hydrogen recovery mechanism. The bottom of the outer cylinder 3 is provided with a bottom plate 5, and the bottom plate 5 is provided with a plurality of through holes. A fixed shaft 6 is connected at the center of the top plate 4 and the bottom plate 5. A separator 7 for auxiliary separation of cleaning and water is spirally wound on the fixed shaft 6. A tail gas inlet pipe 8 is provided on the outer cylinder 3 on one side of the lower end of the separator 7. The other end of the tail gas inlet pipe 8 passes through the outer shell 1 and is connected to the exhaust end of the fuel cell stack.

[0033] A hydrogen auxiliary discharge mechanism is provided on one side of the bottom of the top plate 4 , and a discharge end of the hydrogen auxiliary discharge mechanism is connected to the dilution mechanism after passing through the outer cylinder 3 and the outer shell 1 through an exhaust pipe 27 .

[0034] When the device is in use, the tail gas is sent into the outer tube 3 by connecting the tail gas inlet pipe 8 with the discharge port of the hydrogen fuel cell stack. At this time, the hydrogen rises, and the water is sent into the discharge pipe 2 through the through hole on the bottom plate 5. The hydrogen passes through the separator 7 during the rising process to further separate the water adsorbed on the hydrogen. After the separation during the rising process, the hydrogen is sent to the hydrogen side of the hydrogen fuel cell stack by the hydrogen recovery mechanism for recycling, which greatly increases the use efficiency of hydrogen and reduces the use cost. The device is also provided with a hydrogen auxiliary discharge mechanism and a dilution mechanism. When the hydrogen recovery mechanism fails, the hydrogen is auxiliary discharged by the hydrogen auxiliary discharge mechanism and then diluted by the dilution mechanism, which greatly increases the safety performance of the device.

[0035] A liquid collecting tray 9 is provided below the bottom plate 5, and the outer wall of the liquid collecting tray 9 is fixedly connected to the inner wall of the outer tube 3. The liquid collecting tray 9 is funnel-shaped. A sealing block 10 is also provided in the drain pipe 2 at a position in front of the dilution mechanism. A gap is provided between the sealing block 10 and the bottom inner wall of the drain pipe 2 for liquid to flow through.

[0036] The device is provided with a liquid collecting tray 9 below the bottom plate 5, and the water discharge rate is limited by a funnel-shaped structure. At the same time, a sealing fast setting is used to make the water collection speed much faster than the discharge rate, so that a water seal is provided at the bottom of the bottom plate 5 to prevent leakage at the through hole, and also to prevent hydrogen from flowing back from the drain pipe 2.

[0037] A plurality of separation strips 11 are evenly spaced on the surface of the separation element 7, and the interface of the separation strips 11 is rectangular, thereby increasing the hydrogen adhesion area and further ensuring the separation of hydrogen and water.

[0038] By arranging separation strips 11 on the surface of the separation element 7, the attachment area of ​​the hydrogen is increased, thereby ensuring that the water vapor attached to the hydrogen can be fully removed, thereby ensuring the separation effect.

[0039] The hydrogen recovery mechanism includes a hydrogen circulation pump 12 and a hydrogen return pipe 13. The hydrogen circulation pump 12 is located above the top plate 4. A hydrogen return pipe 13 is provided on one side of the hydrogen circulation pump 12. One end of the hydrogen return pipe 13 passes through the outer cylinder 3 and the outer shell 1 and is connected to the hydrogen side of the fuel cell stack. A connecting component is provided between the hydrogen circulation pump 12 and the outer cylinder 3.

[0040] The hydrogen in the outer tube 3 can be extracted through the operation of the hydrogen circulation pump 12, and then sent to the hydrogen side of the fuel cell stack through the hydrogen return pipe 13 for recycling, thereby increasing the economic benefits of the device.

[0041] The connecting assembly includes a main connecting pipe 14 and an auxiliary connecting pipe 15. The upper end of the main connecting pipe 14 is connected to the hydrogen circulation pump 12. Three groups of auxiliary connecting pipes 15 are provided on the outer wall of the lower end of the main connecting pipe 14. The lower ends of the three groups of auxiliary connecting pipes 15 all pass through the top plate 4 and are inserted into the outer tube 3.

[0042] By providing three groups of auxiliary connecting pipes 15 to cooperate with the structure of the main connecting pipe 14, hydrogen can be adsorbed from three spatial directions, thereby accelerating the adsorption rate.

[0043] The hydrogen auxiliary emission mechanism includes a cavity seat 16, a balloon 17, a gas rod 18, a reset member 19, a discharge pipe 20 and a connecting hole 21. The cavity seat 16 is fixed to the bottom of the top plate 4. The top plate 4 is provided with a balloon 17 at a position directly above the cavity seat 16. The balloon 17 is connected to the air cavity inside the cavity seat 16 through the gas rod 18. A reset member 19 is provided in the air cavity of the cavity seat 16. The outer end of the reset member 19 is exposed inside the outer tube 3. A discharge pipe 20 is provided at the bottom of the cavity seat 16. A connecting hole 21 connected to the discharge pipe 20 is provided below the reset member 19. A plurality of groups of limit plates 32 for limiting the reset member 19 are distributed in a circular array at the position of the exposed end of the reset member 19 on the cavity seat 16.

[0044] The dilution mechanism includes a hydrogen delivery pipe 22, a hydrogen discharge seat 23, an air collection seat 24, an air delivery pipe 25 and an air discharge seat 26. The hydrogen delivery pipe 22 is located inside the drain pipe 2, one end of the hydrogen delivery pipe 22 is connected to the exhaust pipe 27, the other end of the hydrogen delivery pipe 22 is connected to the hydrogen discharge seat 23, the output end of the hydrogen discharge seat 23 faces upward, an air collection seat 24 is provided at the bottom of the drain pipe 2, one end of the air collection seat 24 is provided with an air delivery pipe 25, one end of the air delivery pipe 25 is connected to the air discharge seat 26, the air discharge seat 26 is located directly above the hydrogen discharge seat 23, and the output end of the air discharge seat 26 faces the output end of the hydrogen discharge seat 23.

[0045] When the hydrogen circulation pump 12 of the device fails, the hydrogen in the tail exhaust can no longer be recovered. At this time, as the hydrogen concentration inside the outer tube 3 increases, when the hydrogen completely fills the separation space inside the outer tube 3, the hydrogen pushes the reset member 19 to move in conjunction with the water seal at the bottom, and the air inside the cavity seat 16 is pressed into the balloon 17. When the hydrogen circulation pump 12 can work normally, the reset member 19 can automatically reset through the elastic potential energy of the spring. As the reset member 19 moves, the connecting hole 21 opens, thereby discharging excess hydrogen from the discharge pipe 20, and the discharge pipe 20 discharges. The discharged air sends hydrogen into the drain pipe 2 through the exhaust pipe 27 and is discharged through the hydrogen discharge seat 23, while the air discharge seat 26 opposite to the hydrogen discharge seat 23 discharges air to dilute the hydrogen. Finally, the diluted air is discharged from the drain pipe 2, and the volume of air discharged by the air discharge seat 26 is larger than the volume of hydrogen discharged by the hydrogen discharge seat 23, so that the hydrogen is fully diluted. At the same time, considering the rise of hydrogen, the hydrogen discharge seat 23 is located below the air discharge seat 26, so as to form gas convection, which further increases the dilution effect of hydrogen.

[0046] The supporting mechanism includes a supporting rod 28 . The supporting rods 28 are symmetrically arranged on the outer wall of the hydrogen circulation pump 12 and the outer cylinder 3 . One end of the supporting rod 28 is fixedly connected to the inner wall of the outer shell 1 .

[0047] A liquid recovery hole 29 is provided at the bottom of the drain pipe 2 near the output end, a filter chamber 30 is provided on the outer wall of the bottom of the drain pipe 2 below the liquid recovery hole 29, and a recovery connection pipe port 31 is provided at the lower end of the filter chamber 30.

[0048] When the tail water is discharged, it is collected by the liquid recovery pipe, filtered by the filter chamber 30, and then connected to the cooling mechanism of the automobile through the recovery connection pipe port 31, so that the tail water is recycled, further increasing the economic benefits of the device.

[0049] Using the above tail gas emission device, the emission method includes the following steps:

[0050] S1. When the stack is performing tail discharge, the tail gas is sent into the tail gas separation mechanism through the tail gas inlet pipe 8. Since the tail gas includes hydrogen and water, the hydrogen rises in the tail gas separation mechanism, and the water is discharged through the through holes on the bottom plate 5. The rising hydrogen is sent to the hydrogen side of the stack through the hydrogen circulation pump 12.

[0051] S2, at the same time, the separated water in the tail drain is sent to the liquid collecting tray 9 through the through hole, and at the same time, a blocking block 10 is arranged inside the drain pipe 2 to limit the water discharge rate, so that the water discharge rate is less than the separation rate of the water in the tail drain, so that the water can be collected in the liquid collecting tray 9, thereby forming a water seal to prevent hydrogen from leaking from the drain pipe 2, and further increase the recovery rate of hydrogen;

[0052] S3. When the hydrogen circulation pump 12 fails, the hydrogen in the tail exhaust can no longer be recovered. At this time, as the hydrogen concentration inside the outer tube 3 increases, when the hydrogen completely fills the separation space inside the outer tube 3, the hydrogen pushes the reset member 19 to move in cooperation with the water seal at the bottom. As the reset member 19 moves, the connecting hole 21 opens, thereby discharging excess hydrogen from the discharge pipe 20. The air discharged from the discharge pipe 20 is sent to the inside of the drain pipe 2 through the exhaust pipe 27 and discharged through the hydrogen discharge seat 23, while the air discharge seat 26 opposite to the hydrogen discharge seat 23 discharges air, thereby diluting the hydrogen. Finally, the diluted air is discharged from the drain pipe 2.

[0053] S4. The volume of air discharged from the air discharge seat 26 is greater than the volume of hydrogen discharged from the hydrogen discharge seat 23, so as to fully dilute the hydrogen. Meanwhile, considering the rise of hydrogen, the hydrogen discharge seat 23 is located below the air discharge seat 26, so as to form gas convection and further increase the dilution effect of hydrogen.

[0054] S5. When the tail water is discharged, it is collected through the liquid recovery pipe, filtered through the filter chamber 30, and then connected to the cooling mechanism of the automobile through the recovery connection pipe port 31, so that the tail water is recycled.

[0055] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. An exhaust gas emission device for a hydrogen fuel cell engine, characterized in that: The invention comprises an outer shell (1), an exhaust gas separation mechanism, a hydrogen recovery mechanism, a hydrogen auxiliary discharge mechanism, a support mechanism and a drain pipe (2), wherein the hydrogen recovery mechanism is located above the exhaust gas separation mechanism, the hydrogen recovery mechanism and the exhaust gas separation mechanism are both fixed inside the outer shell (1) via the support mechanism, the bottom of the outer shell (1) is connected to the drain pipe (2), and the discharge end of the drain pipe (2) is provided with a dilution mechanism for diluting hydrogen; The tail gas separation mechanism comprises an outer cylinder (3), a top plate (4), a bottom plate (5), a fixed shaft (6) and a separation member (7); the top of the outer cylinder (3) is provided with a top plate (4), the top plate (4) is connected to the hydrogen recovery mechanism; the bottom of the outer cylinder (3) is provided with a bottom plate (5), the bottom plate (5) is provided with a plurality of through holes; a fixed shaft (6) is connected at the center of the top plate (4) and the bottom plate (5); a separation member (7) for assisting the separation of cleaning and water is spirally wound on the fixed shaft (6); a tail gas inlet pipe (8) is provided on the outer cylinder (3) on one side of the lower end of the separation member (7); the other end of the tail gas inlet pipe (8) passes through the outer shell (1) and is connected to the exhaust end of the fuel cell stack; A hydrogen auxiliary discharge mechanism is provided on one side of the bottom of the top plate (4), and a discharge end of the hydrogen auxiliary discharge mechanism is connected to the dilution mechanism after passing through the outer cylinder (3) and the outer shell (1) through an exhaust pipe (27); The hydrogen recovery mechanism comprises a hydrogen circulation pump (12) and a hydrogen return pipe (13); the hydrogen circulation pump (12) is located above the top plate (4); a hydrogen return pipe (13) is provided on one side of the hydrogen circulation pump (12); one end of the hydrogen return pipe (13) passes through the outer cylinder (3) and the outer shell (1) and is connected to the hydrogen side of the fuel cell stack; a connecting assembly is provided between the hydrogen circulation pump (12) and the outer cylinder (3); The connection assembly comprises a main connection pipe (14) and an auxiliary connection pipe (15), the upper end of the main connection pipe (14) being in communication with the hydrogen circulation pump (12), and three groups of auxiliary connection pipes (15) being provided on the outer side wall of the lower end of the main connection pipe (14), the lower ends of the three groups of auxiliary connection pipes (15) all passing through the top plate (4) and being inserted into the interior of the outer cylinder (3); The hydrogen auxiliary discharge mechanism comprises a cavity seat (16), a balloon (17), an air rod (18), a reset member (19), a discharge pipe (20) and a connecting hole (21); the cavity seat (16) is fixed to the bottom of the top plate (4); a balloon (17) is provided on the top plate (4) at a position directly above the cavity seat (16); the balloon (17) is connected to the air cavity inside the cavity seat (16) through the air rod (18); a reset member (19) is provided in the air cavity of the cavity seat (16); the outer end of the reset member (19) is exposed inside the outer cylinder (3); a discharge pipe (20) is provided at the bottom of the cavity seat (16); a connecting hole (21) connected to the discharge pipe (20) is provided below the reset member (19); and a plurality of groups of limit plates (32) for limiting the position of the reset member (19) are distributed in a ring array at the position of the exposed end of the reset member (19) on the cavity seat (16); The dilution mechanism comprises a hydrogen delivery pipe (22), a hydrogen discharge seat (23), an air collection seat (24), an air delivery pipe (25) and an air discharge seat (26); the hydrogen delivery pipe (22) is located inside the liquid discharge pipe (2); one end of the hydrogen delivery pipe (22) is communicated with an exhaust pipe (27); the other end of the hydrogen delivery pipe (22) is communicated with the hydrogen discharge seat (23); the output end of the hydrogen discharge seat (23) faces upward; an air collection seat (24) is provided at the bottom of the liquid discharge pipe (2); one end of the air collection seat (24) is provided with an air delivery pipe (25); one end of the air delivery pipe (25) is communicated with the air discharge seat (26); the air discharge seat (26) is located directly above the hydrogen discharge seat (23); the output end of the air discharge seat (26) faces the output end of the hydrogen discharge seat (23).

2. The exhaust gas emission device of a hydrogen fuel cell engine according to claim 1, characterized in that: A liquid collecting tray (9) is provided below the bottom plate (5), the outer wall of the liquid collecting tray (9) being fixedly connected to the inner wall of the outer cylinder (3), the liquid collecting tray (9) being funnel-shaped, and a blocking block (10) is provided in the liquid discharge pipe (2) at a position in front of the dilution mechanism, and a gap is provided between the blocking block (10) and the bottom inner wall of the liquid discharge pipe (2) for liquid to flow through.

3. The exhaust gas emission device of a hydrogen fuel cell engine according to claim 1, characterized in that: A plurality of groups of separation strips (11) are distributed at equal intervals on the surface of the separation piece (7), and the interfaces of the separation strips (11) are rectangular.

4. The exhaust gas emission device of a hydrogen fuel cell engine according to claim 1, characterized in that: The support mechanism comprises a support rod (28), and the support rods (28) are symmetrically arranged on the outer walls of the hydrogen circulation pump (12) and the outer cylinder (3), and one end of the support rod (28) is fixedly connected to the inner wall of the outer shell (1).

5. The exhaust gas emission device of a hydrogen fuel cell engine according to claim 1, characterized in that: A liquid recovery hole (29) is provided at the bottom of the liquid discharge pipe (2) on one side close to the output end, a filter chamber (30) is provided on the outer wall of the bottom of the liquid discharge pipe (2) below the liquid recovery hole (29), and a recovery connection pipe port (31) is provided at the lower end of the filter chamber (30).

6. A method for exhaust emission of a hydrogen fuel cell engine according to any one of claims 1 to 5, characterized in that: The steps include: S1. When the stack is exhausting, the exhaust gas is sent to the exhaust gas separation mechanism through the exhaust gas inlet pipe (8). Since the exhaust gas includes hydrogen and water, the hydrogen rises in the exhaust gas separation mechanism, and the water is discharged through the through holes on the bottom plate (5). The rising hydrogen is then sent to the hydrogen side of the stack through the hydrogen circulation pump (12); S2, the water separated from the tail drain is sent into the liquid collecting tray (9) through the through hole, and a sealing block (10) is arranged inside the drain pipe (2) to limit the water discharge rate, so that the water discharge rate is less than the separation rate of the water in the tail drain, so that the water can be collected in the liquid collecting tray (9), thereby forming a water seal, preventing hydrogen from leaking from the drain pipe (2), and further increasing the recovery rate of hydrogen; S3. When the hydrogen circulation pump (12) fails, the hydrogen in the tail exhaust can no longer be recovered. At this time, as the hydrogen concentration inside the outer cylinder (3) increases, when the hydrogen completely fills the separation space inside the outer cylinder (3), the hydrogen pushes the reset member (19) to move in cooperation with the water seal at the bottom. As the reset member (19) moves, the connecting hole (21) opens, thereby discharging excess hydrogen from the discharge pipe (20). The air discharged from the discharge pipe (20) is sent to the inside of the discharge pipe (2) through the exhaust pipe (27) and discharged through the hydrogen discharge seat (23), while the air discharge seat (26) opposite to the hydrogen discharge seat (23) discharges air, thereby diluting the hydrogen. Finally, the diluted air is discharged from the discharge pipe (2); S4. The volume of air discharged from the air discharge seat (26) is greater than the volume of hydrogen discharged from the hydrogen discharge seat (23), so as to fully dilute the hydrogen. Meanwhile, considering the rising of hydrogen, the hydrogen discharge seat (23) is located below the air discharge seat (26), so as to form gas convection, further increasing the dilution effect of hydrogen. S5. When the tail water is discharged, the tail water is collected through the liquid recovery pipe, filtered through the filter chamber (30), and then connected to the cooling mechanism of the vehicle through the recovery connection pipe port (31), so that the tail water is recycled.

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