Air-side oxygen-enriched circulation device for fuel cell power generation system

Abstract

The application provides an air-side oxygen-enriched circulating device for a fuel cell power generation system, and belongs to the technical field of fuel cells, and solves the problem that the prior art cannot effectively utilize cathode oxidants. The device comprises an air circulation branch, a controller, and parallel air compressor gas supply branches and oxygen tank gas supply branches. An air compressor is arranged on the air compressor gas supply branch. An oxygen tank, a pressure reducer, and a cathode ejector are sequentially arranged on the oxygen tank gas supply branch. A tail exhaust back pressure valve, a water distributor, and an electromagnetic valve V1 are sequentially arranged on the air circulation branch. A wet gas inlet of the water distributor is connected to an air tail gas outlet of an electric pile through the tail exhaust back pressure valve, a dry gas outlet of the water distributor is connected to a flow guide inlet of the cathode ejector in one way, and is connected to the electromagnetic valve V1 in another way. The controller is used for adjusting the running states of the air compressor and the electromagnetic valve V1 in real time according to the oxygen concentration of the air entering the electric pile, so that the oxygen concentration of the air entering the electric pile is always maintained within a set range. The device can effectively reduce the cost of oxygen-enriched fixed power generation, and is good in environmental protection.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fuel cell, in particular to an air side oxygen enrichment circulating device for a fuel cell power generation system. BACKGROUND

[0002] In a fuel cell power generation system, hydrogen produces electrons and protons under the action of anode catalyst, and protons combine with oxygen at the cathode to generate water and electrons through a proton membrane. Among them, the high-purity oxygen gas introduced at the cathode side still has a high oxygen content at the outlet of the stack after the reaction, and the direct discharge of the high-quality cathode oxidant is a waste.

[0003] In the existing fuel cell system, a circulating pump or an ejector is added at the anode side to realize the recycling of anode gas and improve the utilization efficiency of hydrogen fuel. However, the cathode side mainly relies on an air compressor, which has high parasitic power consumption and low efficiency. Currently, there is no recycling scheme for oxygen enrichment, which makes the cost of oxygen-enriched fixed power generation high and not environmentally friendly.

[0004] The cathode circulating technology of patent CN115275275A is used for shutdown purging, which uses low-oxygen-content tail gas to purge the remaining water in the stack, and simultaneously removes water and avoids the increase of oxygen content in the stack, but it cannot improve the utilization rate of cathode oxidant. SUMMARY

[0005] In view of the above analysis, the embodiments of the present application aim to provide an air side oxygen enrichment circulating device for a fuel cell power generation system to solve the problem that the prior art cannot effectively utilize the cathode oxidant.

[0006] In one aspect, the embodiments of the present application provide an air side oxygen enrichment circulating device for a fuel cell power generation system, which comprises an air compressor gas supply branch, an oxygen tank gas supply branch, an air circulation branch, and a controller.

[0007] An air compressor is arranged on the air compressor gas supply branch.

[0008] An oxygen tank, a pressure reducer, and a cathode ejector are arranged in sequence on the oxygen tank gas supply branch. The air compressor gas supply branch and the oxygen tank gas supply branch are connected in parallel to the air inlet of the stack.

[0009] A tail gas back pressure valve, a water separator, and an electromagnetic valve V1 are arranged in sequence on the air circulation branch. The air tail gas outlet of the stack is connected to the wet gas inlet of the water separator through the tail gas back pressure valve. One way of the dry gas outlet of the water separator is connected to the flow inlet of the cathode ejector, and the other way is connected to the electromagnetic valve V1 to discharge gas to the external environment.

[0010] The controller is used to adjust the running state of the air compressor and the electromagnetic valve V1 according to the oxygen concentration of the inlet air obtained at a fixed time, so that the oxygen concentration of the inlet air is always maintained within a set range.

[0011] The beneficial effects of the above technical solutions are as follows: the ejector is used on the cathode side of the stack, the oxygen-rich tail gas after the cathode side of the stack is recycled and utilized, the oxygen-rich reflux ratio is adjusted by adjusting the running state of the air compressor and the electromagnetic valve V1 according to the monitored oxygen concentration of the air entering the stack, so as to improve the utilization rate of the cathode oxidant and reduce the power consumption of the fuel cell auxiliary components. The device can effectively reduce the cost of oxygen-rich fixed power generation, has good environmental protection, and has broad market prospects.

[0012] Based on the further improvement of the above device, a cathode main proportional valve and a cathode Bypass proportional valve are further arranged on the oxygen tank gas supply branch.

[0013] The output end of the oxygen tank is connected to the jet inlet of the cathode ejector through the cathode main proportional valve and connected to the confluence outlet of the cathode ejector through the cathode Bypass proportional valve after passing through the pressure reducer.

[0014] The controller is further configured to open the cathode main proportional valve and close the cathode Bypass proportional valve when the required cathode stack power is lower than the set power threshold, and open the cathode Bypass proportional valve and the cathode main proportional valve when the required cathode stack power is higher than the set power threshold.

[0015] Further, the air-side oxygen-rich cycle device further comprises a intercooler and a humidifier.

[0016] The confluence output of the cathode ejector, the output of the air compressor, and the output of the cathode Bypass proportional valve are connected in parallel and then pass through the dry side branch of the intercooler and the humidifier in sequence and enter the air inlet of the stack.

[0017] Further, the controller comprises a data acquisition unit and a data processing and control unit connected in sequence, and the data processing and control unit performs the following program to complete the air oxygen concentration control function:

[0018] The air oxygen concentration entering the stack is acquired at a certain time.

[0019] It is identified whether the air oxygen concentration entering the stack is greater than a set value C1; if yes, the speed of the air compressor is increased, or the opening of the electromagnetic valve V1 is reduced, or the opening duty cycle of the electromagnetic valve V1 is reduced, otherwise, the next step is executed.

[0020] It is identified whether the air oxygen concentration entering the stack is greater than a set value C2; if yes, the speed of the air compressor, the opening of the electromagnetic valve V1, and the opening duty cycle of the electromagnetic valve V1 are maintained unchanged, otherwise, the next step is executed.

[0021] Identify whether the oxygen concentration of the air entering the stack is greater than the set value C3; if so, control the speed of the air compressor to reduce, or the opening of the electromagnetic valve V1 to increase, or the opening duty cycle of the electromagnetic valve V1 to increase, otherwise, switch the fuel cell from the oxygen-rich mode to the air mode, increase the speed of the air compressor to meet the basic power generation demand; the above-mentioned set value C1>C2>C3.

[0022] Further, the air compressor gas supply branch is also provided with an air filter and a flow meter.

[0023] The air filter, flow meter and air compressor are connected in sequence to provide clean air with a set flow rate.

[0024] Further, the data acquisition unit further comprises:

[0025] An oxygen concentration sensor is arranged at the air inlet of the stack or the dry gas branch inlet of the humidifier to obtain the oxygen concentration of the air entering the stack.

[0026] A gas pressure sensor P1 is arranged at the input end of the dry side branch of the humidifier to obtain the pressure of the air entering the stack.

[0027] A gas pressure sensor P2 is arranged at the output end of the pressure reducer to obtain the oxygen pressure at the layout position.

[0028] A gas pressure sensor P3 is arranged at the input end of the intercooler to obtain the pressure of the oxygen-enriched air at the layout position.

[0029] A gas pressure sensor P5 is arranged in the connecting pipeline between the cathode main proportional valve and the ejector to obtain the gas pressure at the jet inlet of the cathode main proportional valve.

[0030] Further, the set value C1 is between 50% and 99%, the set value C2 is between 30% and 90%, and the set value C3 is between 21% and 40%.

[0031] Further, the data acquisition unit further comprises a gas temperature sensor T; wherein,

[0032] The gas temperature sensor T is arranged at the input end of the dry side branch of the humidifier to obtain the temperature of the air entering the stack.

[0033] The controller is further configured to start the intercooler when it is identified that the temperature of the air entering the stack exceeds the set value.

[0034] Further, the air circulation branch is also provided with an electromagnetic valve V2; wherein,

[0035] The input end of the electromagnetic valve V2 is connected to the water outlet of the water distributor, and the output end is connected to the external atmosphere.

[0036] The controller is further configured to start the electromagnetic valve V2 when the liquid level in the water distributor is identified to be higher than the set level.

[0037] Further, an ultrasonic liquid level sensor is arranged in the water distributor to obtain the liquid level in the water distributor.

[0038] Compared with the prior art, the present application can achieve at least one of the following beneficial effects:

[0039] 1. The cathode recirculation technology is used to improve the utilization rate of the cathode oxidant of the fuel cell system.

[0040] 2. The cathode recirculation technology is used to improve the utilization rate of the cathode oxidant of the fuel cell system.

[0041] 3. The cathode recirculation technology is used to improve the utilization rate of the cathode oxidant of the fuel cell system.

[0042] The summary is provided to introduce some choices of concepts in a simplified form, which will be further described in the detailed description below. The summary is not intended to identify important features or essential features of the present disclosure, nor is it intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0043] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout the figures, and in which:

[0044] Figure 1 FIG. 1 shows a schematic diagram of an air-side oxygen-enriched circulation device for a fuel cell power generation system according to an embodiment of the present application;

[0045] Figure 2 FIG. 2 shows a schematic diagram of an air-side oxygen-enriched circulation device for a fuel cell power generation system according to another embodiment of the present application;

[0046] Figure 3 FIG. 3 shows a schematic diagram of the oxygen-enriched recirculation control logic of the controller according to the embodiment of the present application.

[0047] REFERENCE NUMERALS:

[0048] P1, P2, P3, P4, P5 - gas pressure sensor; T - gas temperature sensor. DETAILED DESCRIPTION

[0049] Embodiments of the present disclosure will be described below in greater detail with reference to the accompanying drawings. While embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art.

[0050] The term "comprising" and variations thereof as used herein are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an overly literal or overly formal sense unless expressly so defined herein.

[0051] Embodiment 1

[0052] One embodiment of the present disclosure discloses an air-side oxygen-enriched circulation device for a fuel cell power generation system, as shown in the figure, comprising an air compressor air supply branch, an oxygen tank air supply branch, an air circulation branch, and a controller. Figure 1 The air compressor air supply branch and the oxygen tank air supply branch are connected in parallel to the air inlet of the stack. The input end of the air circulation branch is connected to the air tail gas outlet of the stack, and the output end is also connected to the air inlet of the stack.

[0053] The air compressor air supply branch and the oxygen tank air supply branch are connected in parallel to the air inlet of the stack. The input end of the air circulation branch is connected to the air tail gas outlet of the stack, and the output end is also connected to the air inlet of the stack.

[0054] An air compressor is provided on the air compressor air supply branch to provide pressurized air.

[0055] An oxygen tank, a pressure reducer, and a cathode ejector are provided in sequence on the oxygen tank air supply branch to provide low-pressure pure oxygen.

[0056] A tail gas back pressure valve, a water separator, and a solenoid valve V1 are provided in sequence on the air circulation branch. The air tail gas outlet of the stack is connected to the moisture inlet of the water separator through the tail gas back pressure valve. One way of the dry gas outlet of the water separator is connected to the flow inlet of the cathode ejector, and the other way is connected to the solenoid valve V1 to exhaust to the external environment.

[0057] The controller is used to adjust the operating state of the air compressor and the solenoid valve V1 according to the oxygen concentration of the air entering the stack obtained at regular intervals, so that the oxygen concentration of the air entering the stack is always maintained within the set range, and the utilization rate of the cathode oxidant is improved.

[0058] In implementation, air is pressurized by the air compressor to form pressurized air, the pressurized air is mixed with pure oxygen in the oxygen tank to form oxygen-enriched air, the oxygen-enriched air is humidified and then enters the stack to participate in the oxidation-reduction reaction, the air tail gas discharged from the stack is separated into gas and liquid by the water separation device, and the oxygen-enriched gas is injected back to flow and then mixed with the pure oxygen and the pressurized gas of the air compressor to enter the stack.

[0059] Compared with the prior art, the air-side oxygen-enriched circulating device provided by the embodiment provides a new idea for cathode gas recycling, an ejector is used on the cathode side of the stack to recycle and utilize the oxygen-enriched tail gas discharged from the stack, the oxygen-enriched backflow ratio is adjusted by adjusting the operating state of the air compressor and the electromagnetic valve V1 according to the monitored oxygen concentration of the air entering the stack, so that the utilization rate of the cathode oxidant is improved and the power consumption of the fuel cell auxiliary part is reduced. The device can effectively reduce the cost of oxygen-enriched fixed power generation, has good environmental protection, and has a broad market prospect.

[0060] Embodiment 2

[0061] Based on the improvement of embodiment 1, the oxygen tank gas supply branch is also provided with a cathode main proportional valve and a cathode Bypass proportional valve, as shown in Figure 2 .

[0062] Among them, the output end of the oxygen tank is connected to the jet flow inlet of the cathode ejector through a pressure reducer, and the other end is connected to the confluence outlet of the cathode ejector through the cathode Bypass proportional valve.

[0063] The cathode main proportional valve ensures the pressure at the front end of the ejector (i.e. the data collected by the gas pressure sensor P5). As part of the oxygen supply, the cathode main proportional valve quickly responds to the demand of the stack flow and the pressure at P3 through the cathode Bypass proportional valve in parallel with the cathode main proportional valve to control the pressure at P3 entering the stack.

[0064] The controller is also used to open the cathode main proportional valve and close the cathode Bypass proportional valve when the required cathode stack power is lower than the set power threshold (such as the load current is 0-150 A), and open the cathode Bypass proportional valve and the cathode main proportional valve when the required cathode stack power is higher than the set power threshold (such as the load current is 150-300 A), to complete the circulation.

[0065] The above-mentioned air-side oxygen-enriched circulating device with proportional valves provides two oxygen inlet paths to the stack:

[0066] Path 1: Oxygen is injected from the high-pressure chamber (oxygen tank) to the low-pressure chamber (intercooler) through the cathode Bypass proportional valve to enter the stack;

[0067] Path 2: Oxygen flows from high pressure chamber (oxygen storage tank) to medium pressure chamber (ejector) through proportional valve, and enters the stack through the ejector.

[0068] By controlling the oxygen ratio of the above-mentioned path 1 and path 2, different working parameters of the stack can be further responded.

[0069] Preferably, the air-side oxygen enrichment circulation device further comprises a intercooler and a humidifier.

[0070] The output of the cathode ejector, the output of the air compressor and the output of the cathode Bypass proportional valve are connected in parallel, and then sequentially pass through the dry side branch of the intercooler and the humidifier to enter the air inlet of the stack.

[0071] Preferably, the controller further comprises a data acquisition unit and a data processing and control unit connected in sequence.

[0072] Preferably, the data acquisition unit further comprises an oxygen concentration sensor, a gas temperature sensor T, and gas pressure sensors P1-P5.

[0073] The oxygen concentration sensor is arranged at the air inlet of the stack or the dry gas branch inlet of the humidifier, and is used to obtain the oxygen concentration of the air entering the stack.

[0074] The gas temperature sensor T is arranged at the input end of the dry side branch of the humidifier, and is used to obtain the temperature of the air entering the stack.

[0075] The gas pressure sensor P1 is arranged at the input end of the dry side branch of the humidifier, and is used to obtain the pressure of the air entering the stack.

[0076] The gas pressure sensor P2 is arranged at the output end of the pressure reducer, and is used to obtain the oxygen pressure at the arranged position as a monitoring index of the oxygen pressure at the front end of the main proportional valve.

[0077] The gas pressure sensor P3 is arranged at the input end of the intercooler, and is used to obtain the pressure of the oxygen-enriched air at the arranged position as a monitoring index of the pressure of the mixed oxygen-enriched air, and can be used as a judgment index of whether to open the cathode Bypass proportional valve.

[0078] The gas pressure sensor P4 is arranged at the output end of the wet side branch of the humidifier, and is used to obtain the exhaust gas pressure of the air out of the stack.

[0079] The gas pressure sensor P5 is arranged in the connecting pipeline between the cathode main proportional valve and the ejector, and is used to obtain the gas pressure at the jet inlet of the cathode main proportional valve as another monitoring index of the oxygen pressure at the front end of the main proportional valve, and can be used to judge the ejector return flow.

[0080] Preferably, as Figure 3As shown, the data processing and control unit executes the following procedures to complete the oxygen concentration control function of the air entering the stack:

[0081] S1. Timely obtain the oxygen concentration of the air entering the stack;

[0082] S2. Identify whether the oxygen concentration of the air entering the stack is greater than a set value C1; if yes, control the speed of the air compressor to increase, or the opening of the electromagnetic valve V1 to decrease, or the opening duty cycle of the electromagnetic valve V1 to decrease, otherwise, execute the next step;

[0083] S3. Identify whether the oxygen concentration of the air entering the stack is greater than a set value C2; if yes, maintain the speed of the air compressor, the opening of the electromagnetic valve V1, and the opening duty cycle of the electromagnetic valve V1 unchanged, otherwise, execute the next step;

[0084] S4. Identify whether the oxygen concentration of the air entering the stack is greater than a set value C3; if yes, control the speed of the air compressor to decrease, or the opening of the electromagnetic valve V1 to increase, or the opening duty cycle of the electromagnetic valve V1 to increase, otherwise, switch the fuel cell from the default oxygen-rich mode to the air mode, and increase the speed of the air compressor to meet the basic power generation demand. The set values C1>C2>C3.

[0085] Optionally, in step S4, the set value C1 is 50% to 99%, the set value C2 is 30% to 90%, and the set value C3 is 21% to 40%, and C1>C2>C3 are simultaneously satisfied.

[0086] The controller judges whether the oxygen concentration of the air entering the stack is in the appropriate range by monitoring the oxygen concentration of the air entering the stack, and actively adjusts the opening or duty cycle of the electromagnetic valve V1 of the air compressor and the tail exhaust, so as to ensure the efficient operation of the oxygen-rich mode of the fuel cell.

[0087] Preferably, the set value C1 is 90% to 95%, the set value C2 is 40% to 90%, and the set value C3 is 21% to 40%. Specifically, the set values C1, C2, and C3 are based on the environment, altitude, and maximum power range of the fuel cell.

[0088] Preferably, an air filter and a flowmeter are further arranged on the air supply branch of the air compressor. The air filter, the flowmeter, and the air compressor are connected in sequence to provide clean air with a set flow rate.

[0089] The controller is further configured to start the intercooler when it is identified that the temperature of the air entering the stack exceeds a set value.

[0090] Preferably, an electromagnetic valve V2 is further arranged on the air circulation branch. The input end of the electromagnetic valve V2 is connected to the water outlet of the water distributor, and the output end of the electromagnetic valve V2 is connected to the external atmosphere.

[0091] The controller is further configured to start the electromagnetic valve V2 when it is identified that the liquid level in the water distributor exceeds a set height.

[0092] Preferably, the water distributor is provided with an ultrasonic liquid level sensor for obtaining the liquid level height in the water distributor. The ultrasonic liquid level sensor is not affected by the color and material of the liquid because it does not need to directly contact the liquid. The principle is that ultrasonic waves are sent and reflected back to the sensor after encountering an obstacle, and the distance of the obstacle is calculated according to the time of sending the sound wave and receiving the echo signal, so as to locate the liquid level.

[0093] Compared with the prior art, the air-side oxygen-enriched circulating device provided by the embodiment has the following beneficial effects:

[0094] 1. The cathode injection backflow technology is used to improve the utilization rate of the cathode oxidant of the fuel cell system.

[0095] 2. The cathode injection backflow and the parallel air compressor gas supply branch are used, the exhaust oxygen concentration (also referred to as the tail exhaust oxygen concentration) is monitored, the tail exhaust electromagnetic valve V1 and the air compressor speed are flexibly adjusted, the oxygen-enriched cathode gas low-power consumption circulation is realized, and the effect of flexibly adjusting the cathode oxygen concentration into the stack is realized.

[0096] 3. The injection backflow control strategy based on the oxygen concentration of the air into the stack reduces the power consumption of the auxiliary air compressor and improves the power generation capacity.

[0097] The above has described the embodiments of the present disclosure, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of the terms used herein is intended to best explain the principles, practical application, or improvement of the prior art of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. An air-side oxygen-enriched circulation device for a fuel cell power generation system, characterized by comprising: The air compressor air supply branch, the oxygen tank air supply branch, the air circulation branch, and the controller are included. The air compressor air supply branch is provided with an air compressor. The oxygen tank air supply branch is sequentially provided with an oxygen tank, a pressure reducer, and a cathode ejector. The air circulation branch is sequentially provided with a tail exhaust back pressure valve, a water separator, and an electromagnetic valve V1. The controller is used for adjusting the running states of the air compressor and the electromagnetic valve V1 according to the oxygen concentration of the air entering the stack obtained at a fixed time, so that the oxygen concentration of the air entering the stack is always maintained within a set range. The oxygen tank air supply branch is further provided with a cathode main proportional valve and a cathode Bypass proportional valve. The output end of the oxygen tank is connected to the jet flow inlet of the cathode ejector through the cathode main proportional valve and to the confluence outlet of the cathode ejector through the cathode Bypass proportional valve. The controller is further used for opening the cathode main proportional valve and closing the cathode Bypass proportional valve when the required power generation of the cathode stack is lower than a set power threshold, and opening the cathode Bypass proportional valve and the cathode main proportional valve when the required power generation of the cathode stack is higher than the set power threshold.

2. The air-side oxygen enrichment circulation device for a fuel cell power generation system according to claim 1, characterized by, The air circulation branch is further provided with a middle cooler and a humidifier. The confluence output of the cathode ejector, the output of the air compressor, and the output of the cathode Bypass proportional valve are connected in parallel and sequentially pass through the dry side branch of the middle cooler and the humidifier to enter the air inlet of the stack.

3. The air-side oxygen enrichment circulation device for a fuel cell power generation system according to claim 2, characterized by The controller further includes a data acquisition unit and a data processing and control unit connected in sequence. The data acquisition unit further includes an oxygen concentration sensor, a gas pressure sensor P1, a gas pressure sensor P2, a gas pressure sensor P3, a gas pressure sensor P5, and a gas temperature sensor T. identifying whether the oxygen concentration of the air entering the stack is greater than a set value C 1; if yes, controlling the rotational speed of the air compressor to increase, or the opening of the electromagnetic valve V1 to decrease, or the opening duty cycle of the electromagnetic valve V1 to decrease, otherwise, executing the next step; identifying whether the oxygen concentration of the air entering the stack is greater than a set value C 2; if yes, maintaining the rotation speed of the air compressor, the opening degree of the electromagnetic valve V1, and the opening duty cycle of the electromagnetic valve V1 unchanged, otherwise, performing the next step; identifying whether the oxygen concentration of the air entering the stack is greater than a set value C 3; if yes, control the speed of the air compressor to decrease, or the opening of the electromagnetic valve V1 to increase, or the opening duty cycle of the electromagnetic valve V1 to increase, otherwise, switch the fuel cell from the default oxygen-rich mode to the air mode, and increase the speed of the air compressor to meet the basic power generation demand; the set value C 1> C 2> C 3.

4. The air-side oxygen enrichment circulation device for a fuel cell power generation system according to any one of claims 1 to 3, characterized by The oxygen concentration sensor is arranged at the air inlet of the stack or the dry gas branch inlet of the humidifier and is used for obtaining the oxygen concentration of the air entering the stack. The gas pressure sensor P1 is arranged at the dry side branch input end of the humidifier and is used for obtaining the pressure of the air entering the stack.

5. The air-side oxygen enrichment cycle device for a fuel cell power generation system according to claim 3, characterized by The gas pressure sensor P2 is arranged at the output end of the pressure reducer and is used for obtaining the pressure of the oxygen at the arranged position. The gas pressure sensor P3 is arranged at the input end of the middle cooler and is used for obtaining the pressure of the oxygen-enriched air at the arranged position. The gas pressure sensor P5 is arranged in the connecting pipeline of the cathode main proportional valve and the ejector and is used for obtaining the gas pressure at the jet flow inlet of the cathode main proportional valve. The gas temperature sensor T is arranged at the dry side branch input end of the humidifier and is used for obtaining the temperature of the air entering the stack. The controller is further used for starting the middle cooler when the temperature of the air entering the stack is identified to be higher than a set value. The air circulation branch is further provided with an electromagnetic valve V2.

6. The air-side oxygen enrichment circulation device for a fuel cell power generation system according to claim 3 or 5, characterized by The set value C 1 is between 50% and 99%, set value C 2 is between 30% and 90%, set value C 3 is between 21% and 40%.

7. The air-side oxygen enrichment cycle device for a fuel cell power generation system according to claim 5, characterized by The input end of the electromagnetic valve V2 is connected to the water outlet of the water separator, and the output end thereof is connected to the external atmosphere. ​ ​ 8. The air-side oxygen enrichment cycle apparatus for a fuel cell power generation system according to any one of claims 1, 2, 3, 5, and 7, characterized by ​ ​ The controller is further configured to start the electromagnetic valve V2 when it is identified that the liquid level in the water distributor exceeds a set level.

9. The air-side oxygen enrichment cycle apparatus for a fuel cell power generation system according to claim 8, characterized by An ultrasonic liquid level sensor is arranged in the water distributor to obtain the liquid level in the water distributor.

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