A hydrogen fuel cell tail gas recovery and processing system and method

Abstract

The present invention discloses a hydrogen fuel cell tail gas recovery and processing system and method. By arranging heat exchangers at the outlet of the liquid hydrogen tank, the outlet of the liquid oxygen tank, the rear end of the hydrogen pipeline, and the rear end of the oxygen pipeline, the low temperature characteristics of the vaporization of liquid hydrogen and liquid oxygen can be used to cool the heat exchanger; by adding a No. 2 fuel cell stack at the rear end of the No. 1 fuel cell stack, the residual amount of hydrogen and air in the hydrogen pipeline and the air pipeline can be effectively reduced, and part of the electric energy can be generated for use by low-power loads. The present invention can generate electricity again through the No. 2 fuel cell stack, and can classify and recover the residual fuel through the No. 1-3 heat exchanger, and can be used for reuse, effectively improving the fuel utilization rate; and the whole system will not discharge any liquid or gas to the external environment during operation, which is environmentally friendly and fully meets the use conditions of transportation tools such as vacuum tunnel trains and submarines.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a hydrogen fuel cell tail gas recovery and processing system and method. Background Art

[0002] With the country's vigorous promotion of new energy, fuel cells are gradually being used in various fields. Under common application environments, the residual exhaust gas and water generated by fuel cells during power generation can be directly discharged into the air. However, considering the application of fuel cells in submarines and fuel cell trains in vacuum pipelines, the residual exhaust gas and water generated during power generation cannot be directly discharged into water or air, so special treatment is required for the residual gas of fuel cells.

[0003] For residual gas recovery technology, patent CN205319241U, for example, proposes a hydrogen recovery system with multiple fuel cells, which can reuse residual hydrogen through a hydrogen pump and a buffer container, but it cannot ensure the complete separation of hydrogen from oxygen, water vapor, etc., resulting in impurities such as oxygen being mixed into the anode side of the fuel cell. Another example is patent CN208487415U, which proposes a device that combines hydrogen filling, hydrogen release, and hydrogen recovery. It introduces hydrogen into a hydrogen recovery device through a bypass valve and stores hydrogen by adsorption, but it does not consider the impact of impurities such as oxygen and water vapor in hydrogen on the hydrogen storage system, and some residual gas will still be discharged after adsorption storage. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a hydrogen fuel cell exhaust gas recovery and processing system and method, which can not only effectively separate hydrogen, oxygen, and water vapor, but also effectively store or consume hydrogen, air, and water vapor to adapt to special fuel cell application occasions such as vacuum pipelines or submarines.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a hydrogen fuel cell tail gas recovery and processing system, including a hydrogen pipeline unit, an oxygen pipeline unit, a temperature control pipeline unit, a heat exchanger No. 1, a heat exchanger No. 2, a heat exchanger No. 3, a fuel cell stack No. 1, a fuel cell stack No. 2, a gas compressor, a water storage tank and a gas storage cylinder;

[0006] The hydrogen pipeline unit includes a liquid hydrogen tank, a hydrogen regulating valve, a No. 3 water vapor separator, a hydrogen circulation pump, a No. 4 water vapor separator and a No. 2 three-way valve; the outlet of the liquid hydrogen tank passes through the hydrogen pipeline of the No. 3 heat exchanger, the No. 2 heat exchanger and the No. 1 heat exchanger in sequence, and is connected from the No. 1 heat exchanger outlet to the hydrogen regulating valve inlet, the hydrogen regulating valve outlet is connected to the No. 1 fuel cell stack anode inlet, the No. 1 fuel cell stack anode outlet is connected to the No. 3 water vapor separator, and the gas outlet above the No. 3 water vapor separator is connected to the hydrogen regulating valve outlet through the hydrogen circulation pump; the lower outlet of the No. 3 water vapor separator is connected to the No. 4 water vapor separator, the gas outlet above the No. 4 water vapor separator is connected to the No. 2 three-way valve A inlet, the lower outlet of the No. 4 water vapor separator is connected to the water storage tank, the No. 2 three-way valve B outlet is connected to the gas compressor inlet, the No. 2 three-way valve C outlet is connected to the No. 2 fuel cell stack anode inlet, and the No. 2 fuel cell stack anode outlet is connected to the gas compressor inlet; the gas compressor is connected to the gas storage bottle;

[0007] The oxygen pipeline unit includes a liquid oxygen tank, an oxygen regulating valve, an oxygen circulation pump, a No. 1 water vapor splitter, a No. 2 water vapor separator and a No. 1 three-way valve; the outlet of the liquid oxygen tank is connected to the oxygen pipelines of the No. 3 heat exchanger, the No. 2 heat exchanger and the No. 1 heat exchanger in sequence, and then connected to the inlet of the oxygen regulating valve, the outlet of the oxygen regulating valve is connected to the cathode inlet of the No. 1 fuel cell stack, the cathode outlet of the No. 1 fuel cell stack is connected to the inlet of the No. 1 water vapor separator, the gas outlet above the No. 1 water vapor separator is connected to the inlet of the oxygen circulation pump, the outlet of the oxygen circulation pump merges with the main oxygen loop, the lower outlet of the No. 1 water vapor separator is connected to the No. 2 water vapor separator, the upper outlet of the No. 2 water vapor separator is connected to the inlet of the No. 1 three-way valve A, the lower outlet of the No. 2 water vapor separator is connected to the water storage tank, the outlet of the No. 1 three-way valve B is connected to the inlet of the gas compressor, the outlet of the No. 1 three-way valve C is connected to the cathode inlet of the No. 2 fuel cell stack, and the cathode outlet of the No. 2 fuel cell stack is connected to the inlet of the gas compressor after the pipelines of the No. 1 three-way valve B outlet merge;

[0008] The temperature control pipeline unit includes a water pump, a water pump coolant outlet temperature sensor, a No. 3 three-way valve and a cooling fan; the coolant outlet of the No. 1 fuel cell stack is connected to the water pump inlet, the water pump outlet is connected to the No. 3 three-way valve A inlet after installing the water pump coolant outlet temperature sensor, the No. 3 three-way valve B outlet is connected to the coolant pipelines of the No. 1 heat exchanger, the No. 2 heat exchanger and the No. 3 heat exchanger in turn, and the coolant outlet of the No. 3 heat exchanger is connected to the coolant inlet of the cooling fan, the No. 3 three-way valve C outlet merges with the coolant pipeline of the No. 3 heat exchanger outlet, and is connected to the cooling fan coolant inlet, and the cooling fan coolant outlet is connected to the No. 1 fuel cell stack coolant inlet after installing the stack coolant inlet temperature sensor; the No. 1 heat exchanger temperature sensor, the No. 2 heat exchanger temperature sensor and the No. 3 heat exchanger temperature sensor are respectively arranged on the coolant pipelines of the No. 1 heat exchanger, the No. 2 heat exchanger and the No. 3 heat exchanger.

[0009] Furthermore, it also includes a No. 5 water vapor separator, the No. 2 fuel cell stack anode outlet and the No. 1 three-way valve B outlet are connected to the gas compressor inlet in parallel through the No. 5 water vapor separator, and the gas outlet above the No. 5 water vapor separator is connected to the gas compressor inlet.

[0010] Furthermore, a hydrogen storage alloy container is included, and the outlet of the gas compressor is connected to the hydrogen storage alloy container through the mixed gas pipeline of the No. 1 heat exchanger, the No. 2 heat exchanger and the No. 3 heat exchanger in sequence, and the hydrogen storage alloy container is connected to the gas storage bottle. There is still a small amount of oxygen, hydrogen and water in the tail gas discharged from the No. 2 fuel cell stack. At this time, the pressure of the mixed gas is increased by the gas compressor and pumped to the inlet of the hydrogen storage alloy container. The hydrogen storage alloy container absorbs the hydrogen in the mixed gas, and the residual gas can be compressed into the gas storage bottle.

[0011] Furthermore, it also includes a hydrogen storage tank and an oxygen storage tank. The mixed gas pipeline of heat exchanger No. 1 is discharged to the water storage tank, the mixed gas pipeline of heat exchanger No. 2 is discharged to the oxygen storage tank, and the mixed gas pipeline of heat exchanger No. 3 is discharged to the hydrogen storage tank.

[0012] Furthermore, the temperatures of heat exchanger No. 1, heat exchanger No. 2 and heat exchanger No. 3 are balanced and controlled by utilizing the low temperature characteristics of the liquid hydrogen tank and the liquid oxygen tank and the heat generated when the fuel cell generates electricity, so that the temperature of heat exchanger No. 1 is maintained at 0-10°C, the temperature of heat exchanger No. 2 is maintained at -183-200°C, and the temperature of heat exchanger No. 3 is maintained at -251-255; at the same time, by controlling the gas pressure of the gas compressor to be greater than 5.043MPa to reduce the liquefaction temperature conditions of water, hydrogen and air, heat exchangers No. 1-3 are used to liquefy the water vapor, oxygen and hydrogen in the mixed gas and store them in corresponding storage tanks respectively.

[0013] On the other hand, the present invention also provides a method for recovering and treating tail gas from a hydrogen fuel cell, comprising:

[0014] The oxygen in the No. 1 fuel cell stack is separated by the No. 1 water vapor separator, flows out from the upper outlet of the No. 1 water vapor separator to the oxygen circulation pump, and is pumped into the No. 1 fuel cell stack again for use. Liquid water, gaseous water and residual oxygen are discharged from the lower outlet of the No. 1 water vapor separator. After passing through the No. 2 water vapor separator, the water and oxygen are further separated. The separated oxygen and water vapor mixed gas is passed into the A port of the No. 1 three-way valve, and the large amount of separated liquid water is directly passed into the water storage tank for storage;

[0015] The hydrogen in the No. 1 fuel cell stack is separated by the No. 3 water vapor separator, flows out from the upper outlet of the No. 3 water vapor separator to the hydrogen circulation pump, and is pumped into the No. 1 fuel cell stack for use again. Liquid water, gaseous water and residual hydrogen are discharged from the lower outlet of the No. 3 water vapor separator. After passing through the No. 4 water vapor separator, the water and hydrogen can be further separated. The separated hydrogen and water vapor mixed gas is passed into the A port of the No. 2 three-way valve, and the large amount of separated liquid water is directly passed into the water storage tank for storage;

[0016] The temperatures of heat exchangers No. 1, No. 2, and No. 3 are collected in real time. If the actual temperature of the heat exchanger is higher than the target temperature, the speed of the cooling fan is increased to reduce the temperature. If the actual temperature of the heat exchanger is lower than the target temperature, the speed of the cooling fan is reduced to reduce heat dissipation.

[0017] The working state of the exhaust gas recovery of the hydrogen fuel cell is adjusted by adjusting the opening of three-way valve No. 1, three-way valve No. 2 and three-way valve No. 3.

[0018] Furthermore, if the temperature inside the No. 1 fuel cell stack is too high, the opening of the No. 3 three-way valve is increased to allow more high-temperature coolant to flow through the heat exchanger; if the temperature inside the No. 1 fuel cell stack is too low, the opening of the No. 3 three-way valve is reduced, and the coolant is directly pumped back into the stack after passing through the cooling fan to ensure its rapid warm-up.

[0019] Furthermore, when the No. 2 fuel cell stack is in power generation mode, the A and C interfaces of the No. 1 three-way valve and the No. 2 three-way valve are fully opened, so that the hydrogen and oxygen in the tail gas of the No. 1 fuel cell stack enter the No. 2 fuel cell stack. At this time, the No. 1 fuel cell stack serves as the main power source, and the No. 2 fuel cell stack serves as the power source for low-power loads. When the No. 2 fuel cell stack generates electricity, the residual hydrogen and oxygen discharged from the No. 1 fuel cell stack can be consumed again.

[0020] There is still a small amount of oxygen, hydrogen and water in the exhaust gas discharged from the No. 2 fuel cell stack. At this time, the pressure of the mixed gas is increased by the gas compressor and pumped to the inlet of the hydrogen storage alloy container. The hydrogen storage alloy container absorbs the hydrogen in the mixed gas and the residual gas can be compressed into the gas storage cylinder.

[0021] Furthermore, in the heat exchange separation and storage working state: the A and B interfaces of the No. 1 three-way valve and the No. 2 three-way valve are fully opened. At this time, the No. 1 fuel cell stack serves as the main source of electricity. The residual oxygen, hydrogen, and water vapor mixture discharged by it is separated by the No. 5 water vapor separator, and the liquid water is directly discharged into the water storage tank, and the mixed gas passes through the gas compressor and then enters the No. 1-3 heat exchangers; at this time, the No. 1-3 heat exchangers are in the temperature control heat exchange mode, and at the No. 1 heat exchanger, because the temperature is close to the condensation point of water vapor, the high-temperature water vapor is rapidly cooled and liquefied, and discharged from the bottom of the No. 1 heat exchanger to the water storage tank; at the No. 2 heat exchanger, because the temperature is close to the oxygen condensation point, the oxygen in the mixed gas is rapidly liquefied, and discharged from the bottom of the No. 2 heat exchanger to the oxygen storage tank; at the No. 3 heat exchanger, because the temperature is close to the hydrogen condensation point, the hydrogen is rapidly liquefied, and discharged from the bottom of the No. 3 heat exchanger to the hydrogen storage tank.

[0022] Taking into account that under actual conditions there may still be a small amount of hydrogen that has not turned into liquid, the hydrogen storage alloy container at the end of the mixed gas pipeline can be used to adsorb hydrogen, and the gas storage cylinder can be used to store air and water vapor.

[0023] Furthermore, in the power generation mode + exhaust gas separation and storage working state of fuel cell stack No. 2, fuel cell stack No. 2 first consumes most of the hydrogen and oxygen discharged from fuel cell stack No. 1, and at the same time puts heat exchangers No. 1-3 in temperature control mode, using different temperature levels to liquefy water vapor, oxygen, and air respectively, and store them in the water tank, oxygen tank, and hydrogen tank at the bottom of the heat exchanger. At the end of the mixed gas pipeline, hydrogen-encapsulated alloys and gas cylinders are used to store residual hydrogen, air, and water vapor.

[0024] The beneficial effects of adopting this technical solution are:

[0025] The hydrogen fuel cell exhaust gas recovery and processing system of the present invention can generate electricity again through the No. 2 fuel cell stack, and can classify, recover and store the residual fuel through the No. 1-3 heat exchangers, and can be used for reuse, which effectively improves the fuel utilization rate; and the whole system will not discharge any liquid or gas to the external environment during operation, which is environmentally friendly and fully meets the use conditions of transportation vehicles such as vacuum tunnel trains and submarines.

[0026] The present invention adds a No. 2 fuel cell stack at the rear end of the No. 1 fuel cell stack, which can effectively reduce the residual amount of hydrogen and air in the hydrogen pipeline and the air pipeline, and generate part of the electric energy for use by small power loads, thus achieving the effect of killing two birds with one stone.

[0027] The present invention arranges heat exchangers at the liquid hydrogen tank, the outlet of the liquid oxygen tank, the rear end of the hydrogen pipeline, and the rear end of the oxygen pipeline, and can utilize the low-temperature characteristics of liquid hydrogen vaporization and liquid oxygen vaporization to cool the heat exchanger. The heat exchanger can control the temperature of the heat exchanger by generating heat when the No. 1 fuel cell stack is running, so that the liquid hydrogen and liquid oxygen are heated to a higher temperature before entering the stack. At the same time, the hydrogen, oxygen, and water vapor in the mixed gas pipeline are cooled into liquid water, liquid oxygen, and liquid hydrogen in the No. 1-3 heat exchangers, respectively, and stored in the water storage tank, oxygen storage tank, and hydrogen storage tank. The hydrogen and oxygen in the tail gas discharged by the fuel cell can be effectively recovered, saving energy. Moreover, no gas or liquid will be discharged to the outside during the operation of the entire fuel cell system, and the requirements of special transportation vehicles such as vacuum tunnel trains and underwater submarines can be met.

[0028] The present invention can realize the switching of the system mode only by controlling the opening and closing of the three-way valve and the working mode of the heat exchanger, which is simple and efficient.

[0029] The water, liquid hydrogen, liquid oxygen, hydrogen adsorbed by the hydrogen storage alloy and oxygen in the oxygen storage bottle obtained by cooling the heat exchanger can be further purified and reused, thereby improving the energy utilization rate of the entire fuel cell system.

[0030] The entire fuel cell system of the present invention does not discharge any gas or liquid to the outside, and meets the application conditions of special transportation vehicles such as vacuum tunnel trains and underwater submarines. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic structural diagram of a first embodiment of a hydrogen fuel cell tail gas recovery and processing system of the present invention.

[0032] Figure 2 This is a schematic structural diagram of a second embodiment of the invented hydrogen fuel cell exhaust gas recovery and processing system.

[0033] Figure 3 The present invention is a schematic structural diagram of a third embodiment of a hydrogen fuel cell exhaust gas recovery and processing system.

[0034] Figure 4 This is a schematic structural diagram of a fourth embodiment of a hydrogen fuel cell exhaust gas recovery and processing system of the invention.

[0035] Among them, 1-oxygen circulation pump; 2-oxygen regulating valve; 3-fuel cell stack coolant inlet temperature sensor; 4-No. 1 fuel cell stack; 5-No. 3 water vapor separator; 6-water pump; 7-hydrogen circulation pump; 8-hydrogen regulating valve; 9-gas compressor; 10-No. 3 three-way valve; 11-water pump coolant outlet temperature sensor; 12-cooling fan; 13-No. 1 heat exchanger temperature sensor; 14-No. 2 heat exchanger temperature sensor; 15-No. 3 heat exchanger temperature sensor Sensor; 16-Liquid hydrogen tank; 17-Hydrogen storage alloy container; 18-Gas storage cylinder; 19-Liquid oxygen tank; 20-No. 3 heat exchanger; 21-Hydrogen storage tank; 22-No. 2 heat exchanger; 23-Oxygen storage tank; 24-No. 1 heat exchanger; 25-Water storage tank; 26-No. 5 water vapor separator; 27-No. 2 three-way valve; 28-No. 2 fuel cell stack; 29-No. 4 water vapor separator; 30-No. 1 three-way valve; 31-No. 1 water vapor separator; 32-No. 2 water vapor separator. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described below with reference to the accompanying drawings.

[0037] In this embodiment, see Figure 1 As shown, the present invention proposes a hydrogen fuel cell tail gas recovery and processing system, including a hydrogen pipeline unit, an oxygen pipeline unit, a temperature control pipeline unit, a No. 1 heat exchanger 24, a No. 2 heat exchanger 22, a No. 3 heat exchanger 20, a No. 1 fuel cell stack 4, a No. 2 fuel cell stack 28, a gas compressor 9, a water storage tank 25 and a gas storage bottle 18;

[0038] The hydrogen pipeline unit includes a liquid hydrogen tank 16, a hydrogen regulating valve 8, a No. 3 water vapor separator 5, a hydrogen circulation pump 7, a No. 4 water vapor separator 29 and a No. 2 three-way valve 27; the outlet of the liquid hydrogen tank 16 passes through the hydrogen pipeline of the No. 3 heat exchanger 20, the No. 2 heat exchanger 22 and the No. 1 heat exchanger 24 in sequence, and is connected from the outlet of the No. 1 heat exchanger 24 to the inlet of the hydrogen regulating valve 8, the outlet of the hydrogen regulating valve 8 is connected to the anode inlet of the No. 1 fuel cell stack 4, the anode outlet of the No. 1 fuel cell stack 4 is connected to the No. 3 water vapor separator 5, and the gas outlet above the No. 3 water vapor separator 5 passes through the hydrogen The circulation pump 7 is then connected to the outlet of the hydrogen regulating valve 8; the lower outlet of the No. 3 water vapor separator 5 is connected to the No. 4 water vapor separator 29, the gas outlet above the No. 4 water vapor separator 29 is connected to the inlet of the No. 2 three-way valve 27A, the lower outlet of the No. 4 water vapor separator 29 is connected to the water storage tank 25, the outlet of the No. 2 three-way valve 27B is connected to the inlet of the gas compressor 9, the outlet of the No. 2 three-way valve 27C is connected to the anode inlet of the No. 2 fuel cell stack 28, and the anode outlet of the No. 2 fuel cell stack 28 is connected to the inlet of the gas compressor 9; the gas compressor 99 is connected to the gas storage bottle 18;

[0039] The oxygen pipeline unit includes a liquid oxygen tank 19, an oxygen regulating valve 2, an oxygen circulation pump 1, a No. 1 water vapor splitter, a No. 2 water vapor separator 32 and a No. 1 three-way valve 30; the outlet of the liquid oxygen tank 19 is connected to the oxygen pipelines of the No. 3 heat exchanger 20, the No. 2 heat exchanger 22 and the No. 1 heat exchanger 24 in sequence, and then connected to the inlet of the oxygen regulating valve 2, the outlet of the oxygen regulating valve 2 is connected to the cathode inlet of the No. 1 fuel cell stack 4, the cathode outlet of the No. 1 fuel cell stack 4 is connected to the inlet of the No. 1 water vapor separator 31, and the gas outlet above the No. 1 water vapor separator 31 is connected to the inlet of the oxygen circulation pump 1 The outlet of oxygen circulation pump 1 is connected to the main oxygen loop, the outlet below No. 1 water vapor separator 31 is connected to the inlet of No. 2 water vapor separator 32, the outlet above No. 2 water vapor separator 32 is connected to the inlet of No. 1 three-way valve 30A, the outlet below No. 2 water vapor separator 32 is connected to the water storage tank 25, the outlet of No. 1 three-way valve 30B is connected to the inlet of gas compressor 9, the outlet of No. 1 three-way valve 30C is connected to the inlet of No. 2 fuel cell cathode, and the outlet of No. 2 fuel cell stack 28 cathode is connected to the outlet of No. 1 three-way valve 30B and then connected to the inlet of gas compressor 9 after merging with the pipeline;

[0040] The temperature control pipeline unit includes a water pump 6, a water pump coolant outlet temperature sensor 11, a No. 3 three-way valve 10 and a cooling fan 12; the coolant outlet of the No. 1 fuel cell stack 4 is connected to the inlet of the water pump 6, the outlet of the water pump 6 is connected to the inlet of the No. 3 three-way valve 10A after installing the water pump coolant outlet temperature sensor 11, the outlet of the No. 3 three-way valve 10B is connected to the coolant pipelines of the No. 1 heat exchanger 24, the No. 2 heat exchanger 22 and the No. 3 heat exchanger 20 in sequence, and the coolant outlet of the No. 3 heat exchanger 20 is connected to the cooling fan 12 The coolant inlet, the outlet of the No. 3 three-way valve 10C merges with the coolant pipeline of the No. 3 heat exchanger 20 outlet, and is connected to the coolant inlet of the cooling fan 12. The coolant outlet of the cooling fan 12 is connected to the coolant inlet of the No. 1 fuel cell stack 4 after installing the stack coolant inlet temperature sensor 3; the No. 1 heat exchanger temperature sensor 13, the No. 2 heat exchanger temperature sensor 14 and the No. 3 heat exchanger temperature sensor 15 are respectively arranged on the coolant pipelines of the No. 1 heat exchanger 24, the No. 2 heat exchanger 22 and the No. 3 heat exchanger 20.

[0041] As an optimization solution of the above embodiment, Figure 2 As shown, it also includes a No. 5 water vapor separator 26, the anode outlet of the No. 2 fuel cell stack 28 and the outlet of the No. 1 three-way valve 30B are connected to the inlet of the gas compressor 9 through the No. 5 water vapor separator 26 in parallel, and the gas outlet above the No. 5 water vapor separator 26 is connected to the inlet of the gas compressor 9. The gas entering the gas compressor 9 is separated from water vapor.

[0042] As an optimization solution of the above embodiment, Figure 3As shown, it also includes a hydrogen storage alloy container 17. The outlet of the gas compressor 9 is connected to the hydrogen storage alloy container 17 through the mixed gas pipeline of the No. 1 heat exchanger 24, the No. 2 heat exchanger 22 and the No. 3 heat exchanger 20 in sequence, and the hydrogen storage alloy container 17 is connected to the gas storage bottle 18. There is still a small amount of oxygen, hydrogen and water in the tail gas discharged from the No. 2 fuel cell stack 28. At this time, the pressure of the mixed gas is increased by the gas compressor 9 and pumped to the inlet of the hydrogen storage alloy container 17. The hydrogen storage alloy container 17 absorbs the hydrogen in the mixed gas, and the residual gas can be compressed into the gas storage bottle 18.

[0043] As an optimization solution of the above embodiment, Figure 4 As shown, it also includes a hydrogen storage tank 21 and an oxygen storage tank 23. The mixed gas pipeline of heat exchanger No. 1 24 is discharged to the water storage tank 25, the mixed gas pipeline of heat exchanger No. 2 22 is discharged to the oxygen storage tank 23, and the mixed gas pipeline of heat exchanger No. 3 20 is discharged to the hydrogen storage tank 21.

[0044] As an optimization scheme for the above embodiment, the temperatures of heat exchanger No. 1 24, heat exchanger No. 2 22 and heat exchanger No. 3 20 are balanced and controlled by utilizing the low temperature characteristics of the liquid hydrogen tank 16 and the liquid oxygen tank 19 and the heat generated when the fuel cell generates electricity, so that the temperature of heat exchanger No. 1 24 is maintained at 0-10°C, the temperature of heat exchanger No. 2 22 is maintained at -183--200°C, and the temperature of heat exchanger No. 3 20 is maintained at -251--255; at the same time, by controlling the gas pressure of the gas compressor 9 to be greater than 5.043MPa to reduce the liquefaction temperature conditions of water, hydrogen and air, the water vapor, oxygen and hydrogen in the mixed gas are liquefied by heat exchangers No. 1-3 respectively and stored in corresponding storage tanks.

[0045] The water, liquid hydrogen, liquid oxygen, hydrogen adsorbed by the hydrogen storage alloy and oxygen in the oxygen storage bottle obtained by cooling the heat exchanger can be further purified and reused, thereby improving the energy utilization rate of the entire fuel cell system.

[0046] To cooperate with the implementation of the method of the present invention, based on the same inventive concept, the present invention also provides a hydrogen fuel cell tail gas recovery and treatment method, comprising:

[0047] The oxygen in the No. 1 fuel cell stack 4 is separated by the No. 1 water vapor separator 31, flows out from the upper outlet of the No. 1 water vapor separator 31 to the oxygen circulation pump 1, and is pumped into the No. 1 fuel cell stack 4 for use again. Liquid water, gaseous water and residual oxygen are discharged from the lower outlet of the No. 1 water vapor separator 31. After passing through the No. 2 water vapor separator 32, the water and oxygen are further separated. The separated oxygen and water vapor mixed gas is passed into the No. 1 three-way valve 30A port, and the separated large amount of liquid water is directly passed into the water storage tank 25 for storage;

[0048] The hydrogen in the No. 1 fuel cell stack 4 is separated by the No. 3 water vapor separator 5, flows out from the upper outlet of the No. 3 water vapor separator 5 to the hydrogen circulation pump 7, and is pumped into the No. 1 fuel cell stack 4 for use again. Liquid water, gaseous water and residual hydrogen are discharged from the lower outlet of the No. 3 water vapor separator 5. After passing through the No. 4 water vapor separator 29, the water and hydrogen can be further separated. The separated hydrogen and water vapor mixed gas is passed into the No. 2 three-way valve 27A port, and the separated large amount of liquid water is directly passed into the water storage tank 25 for storage;

[0049] The temperatures of the heat exchanger No. 1 24, the heat exchanger No. 2 22 and the heat exchanger No. 3 20 are collected in real time. If the actual temperature of the heat exchanger is higher than the target temperature, the speed of the cooling fan 12 is increased to reduce the temperature. If the actual temperature of the heat exchanger is lower than the target temperature, the speed of the cooling fan 12 is reduced to reduce heat dissipation.

[0050] The working state of the exhaust gas recovery of the hydrogen fuel cell is adjusted by adjusting the openings of the No. 1 three-way valve 30, the No. 2 three-way valve 27 and the No. 3 three-way valve 10.

[0051] As an optimization scheme of the above embodiment, if the temperature inside the No. 1 fuel cell stack 4 is too high, the opening of the No. 3 three-way valve 10 is increased to allow more high-temperature coolant to flow through the heat exchanger; if the temperature inside the No. 1 fuel cell stack 4 is too low, the opening of the No. 3 three-way valve 10 is reduced, and the coolant is directly pumped back into the stack after passing through the cooling fan 12 to ensure its rapid warm-up.

[0052] As an optimization scheme for the above embodiment, three working states are included: the No. 2 fuel cell stack 28 power generation mode working state, the heat exchange separation storage working state and the No. 2 fuel cell stack 28 power generation mode + exhaust gas separation storage working state.

[0053] In the working state of the No. 2 fuel cell stack 28 power generation mode: the A and C interfaces of the No. 1 three-way valve 30 and the No. 2 three-way valve 27 are fully opened, so that the hydrogen and oxygen in the tail gas of the No. 1 fuel cell stack 4 enter the No. 2 fuel cell stack 28. At this time, the No. 1 fuel cell stack 4 serves as the main power source, and the No. 2 fuel cell stack 28 serves as the power source for low-power loads; when the No. 2 fuel cell stack 28 generates electricity, the residual hydrogen and oxygen discharged by the No. 1 fuel cell stack 4 can be consumed again;

[0054] There is still a small amount of oxygen, hydrogen and water in the exhaust gas discharged from the No. 2 fuel cell stack 28. At this time, the pressure of the mixed gas is increased by the gas compressor 9 and pumped to the inlet of the hydrogen storage alloy container 17. The hydrogen storage alloy container 17 adsorbs the hydrogen in the mixed gas, and the residual gas can be compressed into the gas storage bottle 18.

[0055] In the heat exchange separation storage working state: the A and B interfaces of the No. 1 three-way valve 30 and the No. 2 three-way valve 27 are fully opened. At this time, the No. 1 fuel cell stack 4 is used as the main power source. The residual oxygen, hydrogen, and water vapor mixed gas discharged by it is separated by the No. 5 water vapor separator 26, and the liquid water is directly discharged into the water storage tank 25. The mixed gas passes through the gas compressor 9 and then enters the No. 1-3 heat exchanger 20; at this time, the No. 1-3 heat exchanger 20 is in the temperature control heat exchange mode, then At heat exchanger No. 1 24 , since the temperature is close to the condensation point of water vapor, the high-temperature water vapor is rapidly cooled and liquefied, and is discharged from the bottom of heat exchanger No. 1 24 to the water storage tank 25; at heat exchanger No. 2 22 , since the temperature is close to the condensation point of oxygen, the oxygen in the mixed gas is rapidly liquefied, and is discharged from the bottom of heat exchanger No. 2 22 to the oxygen storage tank 23; at heat exchanger No. 3 20 , since the temperature is close to the condensation point of hydrogen, the hydrogen is rapidly liquefied, and is discharged from the bottom of heat exchanger No. 3 20 to the hydrogen storage tank 21.

[0056] Considering that there may still be a small amount of hydrogen that has not turned into liquid under actual conditions, the hydrogen storage alloy container 17 at the end of the mixed gas pipeline can be used to adsorb hydrogen, and the gas storage bottle 18 can be used to store air and water vapor.

[0057] In the power generation mode + exhaust gas separation and storage working state of fuel cell stack No. 2 28, fuel cell stack No. 2 28 first consumes most of the hydrogen and oxygen discharged from fuel cell stack No. 1 4, and at the same time puts heat exchangers No. 1-3 20 in temperature control mode, and uses different temperature levels to liquefy water vapor, oxygen, and air respectively, and store them in the water storage tank 25, oxygen storage tank 23, and hydrogen storage tank 21 at the bottom of the heat exchanger. At the end of the mixed gas pipeline, hydrogen encapsulation alloy and gas storage bottle 18 are used to store residual hydrogen, air and water vapor.

[0058] The above shows and describes the basic principles and main features of the present invention and the 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 to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A hydrogen fuel cell tail gas recovery and processing system, characterized in that: It includes a hydrogen pipeline unit, an oxygen pipeline unit, a temperature control pipeline unit, a No. 1 heat exchanger (24), a No. 2 heat exchanger (22), a No. 3 heat exchanger (20), a No. 1 fuel cell stack (4), a No. 2 fuel cell stack (28), a gas compressor (9), a water storage tank (25) and a gas storage cylinder (18); The hydrogen pipeline unit comprises a liquid hydrogen tank (16), a hydrogen regulating valve (8), a No. 3 water vapor separator (5), a hydrogen circulation pump (7), a No. 4 water vapor separator (29) and a No. 2 three-way valve (27); the outlet of the liquid hydrogen tank (16) passes through the hydrogen pipeline of the No. 3 heat exchanger (20), the No. 2 heat exchanger (22) and the No. 1 heat exchanger (24) in sequence, and is connected from the outlet of the No. 1 heat exchanger (24) to the inlet of the hydrogen regulating valve (8), the outlet of the hydrogen regulating valve (8) is connected to the anode inlet of the No. 1 fuel cell stack (4), the anode outlet of the No. 1 fuel cell stack (4) is connected to the No. 3 water vapor separator (5), and the No. 3 water vapor separator (5) is connected to the anode outlet of the No. 1 fuel cell stack (4). The gas outlet at the top passes through a hydrogen circulation pump (7) and is then connected to the outlet of a hydrogen regulating valve (8); the outlet at the bottom of the No. 3 water vapor separator (5) is connected to the No. 4 water vapor separator (29); the gas outlet at the top of the No. 4 water vapor separator (29) is connected to the A inlet of the No. 2 three-way valve (27); the outlet at the bottom of the No. 4 water vapor separator (29) is connected to the water storage tank (25); the outlet B of the No. 2 three-way valve (27) is connected to the inlet of a gas compressor (9); the outlet C of the No. 2 three-way valve (27) is connected to the anode inlet of the No. 2 fuel cell stack (28); and the anode outlet of the No. 2 fuel cell stack (28) is connected to the inlet of a gas compressor (9); The oxygen pipeline unit comprises a liquid oxygen tank (19), an oxygen regulating valve (2), an oxygen circulation pump (1), a No. 1 water vapor splitter, a No. 2 water vapor separator (32) and a No. 1 three-way valve (30); the outlet of the liquid oxygen tank (19) is connected to the oxygen pipelines of the No. 3 heat exchanger (20), the No. 2 heat exchanger (22) and the No. 1 heat exchanger (24) in sequence, and then connected to the inlet of the oxygen regulating valve (2); the outlet of the oxygen regulating valve (2) is connected to the cathode inlet of the No. 1 fuel cell stack (4); the cathode outlet of the No. 1 fuel cell stack (4) is connected to the inlet of the No. 1 water vapor separator (31); the gas outlet above the No. 1 water vapor separator (31) is connected to the inlet of the oxygen circulation pump (1); and the oxygen circulation The outlet of the pump (1) merges with the main oxygen circuit, the lower outlet of the No. 1 water vapor separator (31) is connected to the No. 2 water vapor separator (32), the upper outlet of the No. 2 water vapor separator (32) is connected to the A inlet of the No. 1 three-way valve (30), the lower outlet of the No. 2 water vapor separator (32) is connected to the water storage tank (25), the B outlet of the No. 1 three-way valve (30) is connected to the inlet of the gas compressor (9), the C outlet of the No. 1 three-way valve (30) is connected to the cathode inlet of the No. 2 fuel cell stack (28), the cathode outlet of the No. 2 fuel cell stack (28) and the pipeline of the B outlet of the No. 1 three-way valve (30) are merged and then connected to the inlet of the gas compressor (9); the gas compressor (9) is connected to the gas storage bottle (18); The temperature control pipeline unit comprises a water pump (6), a water pump coolant outlet temperature sensor (11), a No. 3 three-way valve (10) and a heat dissipation fan (12); the coolant outlet of the No. 1 fuel cell stack (4) is connected to the inlet of the water pump (6), the outlet of the water pump (6) is connected to the inlet A of the No. 3 three-way valve (10) after installing the water pump coolant outlet temperature sensor (11), the outlet of the No. 3 three-way valve (10) is connected to the coolant pipeline of the No. 1 heat exchanger (24), the No. 2 heat exchanger (22) and the No. 3 heat exchanger (20) in sequence, and the coolant outlet of the No. 3 heat exchanger (20) is connected to the heat dissipation fan ( 12) coolant inlet, the coolant pipeline of the No. 3 three-way valve (10) C outlet merges with the coolant pipeline of the No. 3 heat exchanger (20) outlet, and is connected to the coolant inlet of the heat dissipation fan (12), and the coolant outlet of the heat dissipation fan (12) is connected to the coolant inlet of the No. 1 fuel cell stack (4) after installing the stack coolant inlet temperature sensor (3); the No. 1 heat exchanger temperature sensor (13), the No. 2 heat exchanger temperature sensor (14) and the No. 3 heat exchanger temperature sensor (15) are respectively arranged on the coolant pipelines of the No. 1 heat exchanger (24), the No. 2 heat exchanger (22) and the No. 3 heat exchanger (20); It also includes a hydrogen storage tank (21) and an oxygen storage tank (23); the mixed gas pipeline of the No. 1 heat exchanger (24) is discharged to the water storage tank (25); the mixed gas pipeline of the No. 2 heat exchanger (22) is discharged to the oxygen storage tank (23); and the mixed gas pipeline of the No. 3 heat exchanger (20) is discharged to the hydrogen storage tank (21).

2. A hydrogen fuel cell tail gas recovery and processing system according to claim 1, characterized in that: It also includes a No. 5 water vapor separator (26), the anode outlet of the No. 2 fuel cell stack (28) and the B outlet of the No. 1 three-way valve (30) are connected to the inlet of the gas compressor (9) in parallel through the No. 5 water vapor separator (26), and the gas outlet above the No. 5 water vapor separator (26) is connected to the inlet of the gas compressor (9).

3. A hydrogen fuel cell tail gas recovery and processing system according to claim 2, characterized in that: It also includes a hydrogen storage alloy container (17), wherein the outlet of the gas compressor (9) is connected to the hydrogen storage alloy container (17) through a mixed gas pipeline of a No. 1 heat exchanger (24), a No. 2 heat exchanger (22) and a No. 3 heat exchanger (20) in sequence, and the hydrogen storage alloy container (17) is connected to a gas storage cylinder (18).

4. A hydrogen fuel cell tail gas recovery and processing system according to claim 1, characterized in that: The temperatures of heat exchanger No. 1 (24), heat exchanger No. 2 (22) and heat exchanger No. 3 (20) are balanced and controlled by utilizing the low temperature characteristics of the liquid hydrogen tank (16) and the liquid oxygen tank (19) and the heat generated when the fuel cell generates electricity, so that the temperature of heat exchanger No. 1 (24) is maintained at 0 to 10°C, the temperature of heat exchanger No. 2 (22) is maintained at -183 to -200°C, and the temperature of heat exchanger No. 3 (20) is maintained at -251 to -255°C; at the same time, the gas pressure of the gas compressor (9) is controlled to be greater than 5.043MPa.

5. A method for recovering and treating tail gas from a hydrogen fuel cell, characterized in that: The hydrogen fuel cell tail gas recovery and processing system according to any one of claims 1 to 4 comprises: Oxygen in the No. 1 fuel cell stack (4) is separated by the No. 1 water vapor separator (31), flows out from the upper outlet of the No. 1 water vapor separator (31) to the oxygen circulation pump (1), and is pumped into the No. 1 fuel cell stack (4) for utilization again. Liquid water, gaseous water and residual oxygen are discharged from the lower outlet of the No. 1 water vapor separator (31). After passing through the No. 2 water vapor separator (32), water and oxygen are further separated. The separated oxygen and water vapor mixed gas is passed into the A port of the No. 1 three-way valve (30), and the large amount of separated liquid water is directly passed into the water storage tank (25) for storage; The hydrogen in the No. 1 fuel cell stack (4) is separated by the No. 3 water vapor separator (5), flows out from the upper outlet of the No. 3 water vapor separator (5) to the hydrogen circulation pump (7), and is pumped into the No. 1 fuel cell stack (4) for utilization again. Liquid water, gaseous water and residual hydrogen are discharged from the lower outlet of the No. 3 water vapor separator (5). After passing through the No. 4 water vapor separator (29), the water and hydrogen can be further separated. The separated hydrogen and water vapor mixed gas is passed into the A port of the No. 2 three-way valve (27), and the large amount of separated liquid water is directly passed into the water storage tank (25) for storage; The temperatures of heat exchanger No. 1 (24), heat exchanger No. 2 (22) and heat exchanger No. 3 (20) are collected in real time. If the actual temperature of the heat exchanger is higher than the target temperature, the speed of the heat dissipation fan (12) is increased to reduce the temperature. If the actual temperature of the heat exchanger is lower than the target temperature, the speed of the heat dissipation fan (12) is reduced to reduce heat dissipation. The working state of tail gas recovery of the hydrogen fuel cell is adjusted by adjusting the openings of the No. 1 three-way valve (30), the No. 2 three-way valve (27) and the No. 3 three-way valve (10).

6. A method for recovering and treating tail gas from a hydrogen fuel cell according to claim 5, characterized in that: If the temperature inside the No. 1 fuel cell stack (4) is too high, the opening of the No. 3 three-way valve (10) is increased to allow more high-temperature coolant to flow through the heat exchanger; if the temperature inside the No. 1 fuel cell stack (4) is too low, the opening of the No. 3 three-way valve (10) is reduced to allow the coolant to be directly pumped back into the stack after passing through the heat dissipation fan (12) to ensure rapid warm-up.

7. A method for recovering and treating tail gas from a hydrogen fuel cell according to claim 5, characterized in that: When the No. 2 fuel cell stack (28) is in power generation mode, the A and C interfaces of the No. 1 three-way valve (30) and the No. 2 three-way valve (27) are fully opened, so that the hydrogen and oxygen in the tail gas of the No. 1 fuel cell stack (4) enter the No. 2 fuel cell stack (28). At this time, the No. 1 fuel cell stack (4) serves as the main power source, and the No. 2 fuel cell stack (28) serves as the power source for low-power loads; when the No. 2 fuel cell stack (28) generates electricity, the residual hydrogen and oxygen discharged from the No. 1 fuel cell stack (4) can be consumed again; There is still a small amount of oxygen, hydrogen and water in the tail gas discharged from the No. 2 fuel cell stack (28). At this time, the pressure of the mixed gas is increased by the gas compressor (9) and pumped to the inlet of the hydrogen storage alloy container (17). The hydrogen storage alloy container (17) adsorbs the hydrogen in the mixed gas, and the residual gas can be compressed into the gas storage bottle (18).

8. A method for recovering and treating tail gas from a hydrogen fuel cell according to claim 5, characterized in that: In the heat exchange separation storage working state: the A and B interfaces of the No. 1 three-way valve (30) and the No. 2 three-way valve (27) are fully opened. At this time, the No. 1 fuel cell stack (4) serves as the main power source. The residual oxygen, hydrogen and water vapor mixed gas discharged by it is separated by the No. 5 water vapor separator (26), and the liquid water is directly discharged into the water storage tank (25). The mixed gas passes through the gas compressor (9) and then enters the No. 1-3 heat exchanger (20); at this time, the No. 1-3 heat exchanger (20) is in the temperature control heat exchange mode, and then in Since the temperature at the No. 1 heat exchanger (24) is close to the condensation point of water vapor, the high-temperature water vapor is rapidly cooled and liquefied, and is discharged from the bottom of the No. 1 heat exchanger (24) to the water storage tank (25); since the temperature at the No. 2 heat exchanger (22) is close to the condensation point of oxygen, the oxygen in the mixed gas is rapidly liquefied, and is discharged from the bottom of the No. 2 heat exchanger (22) to the oxygen storage tank (23); since the temperature at the No. 3 heat exchanger (20) is close to the condensation point of hydrogen, the hydrogen is rapidly liquefied, and is discharged from the bottom of the No. 3 heat exchanger (20) to the hydrogen storage tank (21).

9. A method for recovering and treating tail gas from a hydrogen fuel cell according to claim 5, characterized in that: In the No. 2 fuel cell stack (28) power generation mode + tail gas separation and storage working state, the No. 2 fuel cell stack (28) first consumes most of the hydrogen and oxygen discharged by the No. 1 fuel cell stack (4), and at the same time puts the No. 1-3 heat exchangers (20) in a temperature control mode, and uses different temperature levels to liquefy water vapor, oxygen, and air respectively, and store them in the water storage tank (25), oxygen storage tank (23), and hydrogen storage tank (21) at the bottom of the heat exchanger. At the end of the mixed gas pipeline, a hydrogen-encapsulated alloy and a gas storage bottle (18) are used to store residual hydrogen, air, and water vapor.

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