Combination heat and power air supply system of fuel cell

Abstract

The utility model provides a combined heat and power supply air supply system of a fuel cell, which utilizes a byproduct high-pressure pure oxygen generated by hydrogen production through water electrolysis as a working fluid, realizes air humidification and cyclic utilization of electric pile waste gas through combination of an injection device and an air compressor branch, reduces the use of a humidifier and an intercooler, and reduces the complexity and air flow resistance of the system. The system comprises an air inlet main path, an oxygen inlet branch path, an air inlet branch path and an injection device, waste oxygen is introduced into the oxygen inlet branch path, the air inlet branch path is provided with an air compressor, and the injection device mixes the waste oxygen and fresh air and supplies the mixed waste oxygen and fresh air into a galvanic pile. The air outlet pipeline is connected with the water segregator, waste gas is recycled to humidify fresh air, and a backflow adjusting valve is arranged. The system reduces the power consumption of the air compressor and improves the cogeneration efficiency of the fuel cell.

Description

Technical Field

[0001] This utility model relates to the field of fuel cell technology, and in particular to a fuel cell combined heat and power air supply system. Background Technology

[0002] A fuel cell combined heat and power (CHP) system is a highly efficient energy utilization device that combines fuel cell power generation technology with heat recovery. It converts the chemical energy of hydrogen and an oxidant (usually oxygen from the air) into electrical and thermal energy through an electrochemical reaction, simultaneously meeting the user's electricity and heat demands. In existing technologies, the power generation efficiency of a fuel cell CHP system is one of the key performance indicators, and the design of the air supply system directly affects the power generation efficiency and system complexity.

[0003] Currently, air supply for fuel cell combined heat and power systems typically involves forced air delivery to the fuel cell stack using an air compressor. After being filtered, the air is pressurized to the required pressure by the compressor, then cooled by an intercooler and humidified by a humidifier before entering the stack to participate in the reaction. However, this traditional approach has the following significant drawbacks:

[0004] High-pressure pure oxygen byproduct is not utilized: In the process of producing hydrogen through water electrolysis, in addition to hydrogen, a large amount of high-pressure pure oxygen is also generated. In existing technologies, this byproduct oxygen is usually directly discharged as waste gas or stored for later use, without being utilized in conjunction with the air supply system, resulting in resource waste.

[0005] High energy consumption of air compressors: Air compressors need to pressurize air to high pressure to meet the needs of fuel cell reactor reaction. Their power consumption accounts for 20% to 30% of the total power generation of the system, which seriously reduces the overall power generation efficiency of the system.

[0006] The system is complex and has high flow resistance: Traditional solutions require humidifiers to humidify the incoming air, but the presence of humidifiers increases the flow resistance of the air ducts and requires additional humidity control, which increases the complexity of the system.

[0007] Low thermal management efficiency: The air temperature at the air compressor outlet is relatively high, requiring cooling through an intercooler, which increases the heat dissipation burden and component costs.

[0008] Existing solutions result in the inability to utilize high-pressure pure oxygen, and the use of an air compressor for pumping requires additional power consumption, reducing the power generation efficiency of the fuel cell cogeneration system. Publication number CN117293367A discloses a novel air intake system suitable for proton exchange membrane hydrogen fuel cells, eliminating the need for an air compressor and associated cooling system, thus reducing equipment investment and floor space. However, the high power consumption problem of the air compressor remains unresolved.

[0009] To address the aforementioned issues, there is an urgent need for a fuel cell air supply system that can integrate oxygen produced as a byproduct of water electrolysis, reduce air compressor energy consumption, and simplify the system structure. Utility Model Content

[0010] To address the shortcomings of existing technologies, this invention provides a fuel cell cogeneration air supply system that utilizes high-pressure pure oxygen as a byproduct of hydrogen production via water electrolysis, while simultaneously reducing air compressor power consumption and improving fuel cell cogeneration power generation efficiency.

[0011] This utility model provides a fuel cell cogeneration air supply system, including a fuel cell stack, an air inlet pipe for supplying air to the fuel cell stack, and an air outlet pipe for discharging exhaust air from the fuel cell stack. The air inlet pipe includes:

[0012] The main air intake path connects downstream to the fuel cell stack.

[0013] The oxygen supply branch includes oxygen sources and proportional valves distributed sequentially from upstream to downstream;

[0014] The air intake branch includes air compressors and air intake regulating valves distributed sequentially from upstream to downstream;

[0015] The injection device includes a first inlet, a second inlet, and an outlet. The first inlet is connected to the downstream end of the oxygen intake branch, the second inlet is connected to the downstream end of the air intake branch, and the outlet is connected to the upstream end of the main air intake branch.

[0016] The air outlet pipe is connected to the water distributor, which includes an air outlet and a water outlet. The air outlet is connected to the second inlet of the injection device through a return pipe, and a return regulating valve is provided on the return pipe.

[0017] Furthermore, the main air intake path is equipped with an intercooler and a regulating valve sequentially from upstream to downstream. The intercooler, by lowering the intake air temperature, can improve the fuel cell's operating efficiency, reduce heat loss, and help extend the stack's lifespan. Simultaneously, the use of an intercooler also helps reduce the power consumption of the air compressor, as cooled air is easier to compress.

[0018] Furthermore, the main air intake circuit is equipped with a first pressure sensor and a first temperature sensor between the intercooler and the regulating valve to monitor air pressure and temperature in real time. This allows the system to more accurately adjust the operating status of the air compressor and the proportional valve to ensure the stability and efficiency of the air supply.

[0019] Furthermore, the oxygen inlet branch is equipped with a first flow meter and a pressure reducing valve between the oxygen source and the proportional valve to precisely control the oxygen flow and pressure, ensuring that the oxygen-air mixing ratio reaches the optimal state. The use of the pressure reducing valve can also protect the system from potential damage from high-pressure oxygen.

[0020] Furthermore, the air intake branch is equipped with an air filter at the air intake end, which can extend the service life of the air compressor and reduce system maintenance costs; a second pressure sensor and a second temperature sensor are provided between the air filter and the air compressor, which can monitor the air pressure and temperature at the air compressor inlet in real time, helping the system to adjust the working status of the air compressor more accurately.

[0021] Furthermore, the injection device is an ejector, with the first inlet serving as the nozzle port and the second inlet as the ejector port, simplifying the system structure and reducing system complexity. Simultaneously, the more uniform mixing of oxygen and air improves the power generation efficiency of the fuel cell.

[0022] Furthermore, a third pressure sensor and a third temperature sensor are provided on the air outlet pipeline.

[0023] Furthermore, the outlet of the water distributor is connected to a drain pipe, and a drain valve is installed on the drain pipe. Even further, a silencer is installed at the downstream end of the drain valve on the drain pipe.

[0024] Timely drainage of condensate through the drainage pipes ensures the normal operation of the system and extends the lifespan of the fuel cell stack. Meanwhile, the use of a silencer reduces noise pollution.

[0025] Overall:

[0026] 1. This fuel cell cogeneration air supply system can utilize the waste oxygen generated during hydrogen production via water electrolysis.

[0027] 2. By using waste oxygen as the working fluid and employing a jetting device, the waste gas from the fuel cell stack can be recycled to humidify the fresh gas. This reduces the number of humidifiers in the system, thereby lowering the complexity of the air supply system and the flow resistance of the incoming air.

[0028] 3. By using waste oxygen as the working fluid in the injection device, the waste gas from the fuel cell stack can be recycled back into the fuel cell stack, reducing the air flow rate entering the fuel cell stack through the air compressor branch.

[0029] 4. Waste oxygen is cooled a second time after passing through the ejector. At the same time, the pressure ratio before and after the air compressor is reduced, the air compressor outlet temperature is reduced, the intercooler is reduced in the system, and the complexity of the air supply system and the flow resistance of the incoming air are further reduced.

[0030] 5. The reduced inlet and outlet pressure ratio of the air compressor leads to a decrease in the air flow through the air compressor branch, resulting in reduced power consumption of the air compressor and improved power generation efficiency of the fuel cell cogeneration system.

[0031] The beneficial effects of this utility model are:

[0032] This utility model's fuel cell cogeneration air supply system integrates high-pressure pure oxygen, a byproduct of hydrogen production from water electrolysis, and utilizes an injection device to recycle waste gas and waste oxygen, simplifying the system structure and reducing system complexity and energy consumption. Simultaneously, by reducing the use of humidifiers and intercoolers, the system complexity and flow resistance are further reduced. These innovations work together to significantly improve the efficiency of the air compressor and reduce power consumption, thereby enhancing the overall power generation efficiency and economy of the fuel cell cogeneration system. Furthermore, the system also boasts advantages such as environmental friendliness, reliability, and ease of maintenance, providing strong support for the widespread application of fuel cell cogeneration systems. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the air supply system for the fuel cell cogeneration of this utility model.

[0034] The diagram is labeled as follows: 1-fuel cell stack, 2-oxygen source, 3-proportional valve, 4-air compressor, 5-inlet air regulating valve, 6-injection device, 61-first inlet, 62-second inlet, 63-outlet, 7-water distributor, 71-air outlet, 72-water outlet, 8-recirculation regulating valve, 9-intercooler, 10-regulating valve, 11-first pressure sensor, 12-first temperature sensor, 13-first flow meter, 14-pressure reducing valve, 15-air filter, 16-second pressure sensor, 17-second temperature sensor, 18-third pressure sensor, 19-third temperature sensor, 20-drain valve, 21-silencer, 22-second flow meter. Detailed Implementation

[0035] This utility model provides an air supply system for a fuel cell cogeneration system, including a fuel cell stack 1 and an air inlet pipe for supplying air to the fuel cell stack 1 and an air outlet pipe for discharging exhaust air from the fuel cell stack. The air inlet pipe includes: a main air inlet line, the downstream end of which is connected to the fuel cell stack 1; an oxygen inlet branch line, including an oxygen source 2 and a proportional valve 3 distributed sequentially from upstream to downstream; an air inlet branch line, including an air compressor 4 and an air inlet regulating valve 5 distributed sequentially from upstream to downstream; an injection device 6, including a first inlet 61, a second inlet 62, and an outlet 63, the first inlet 61 being connected to the downstream end of the oxygen inlet branch line, the second inlet 62 being connected to the downstream end of the air inlet branch line, and the outlet 63 being connected to the upstream end of the main air inlet line; the air outlet pipe is connected to a water distributor 7, the water distributor 7 including an air outlet 71 and a water outlet 72, the air outlet 71 being connected to the second inlet 62 of the injection device 6 through a return pipe, and a return regulating valve 8 is provided on the return pipe.

[0036] Specifically, the main air intake line is equipped with an intercooler 9 and a regulating valve 10 from the upstream end to the downstream end. The intercooler is located on the main air intake line and is used to cool the high-temperature air after compression by the air compressor, so as to reduce the temperature of the air before it enters the fuel cell stack.

[0037] The main air intake circuit is equipped with a first pressure sensor 11 and a first temperature sensor 12 between the intercooler 9 and the regulating valve 10. These sensors can monitor the air pressure and temperature in the main air intake circuit and provide real-time data for system control and monitoring.

[0038] In order to precisely control the oxygen flow rate and pressure, the oxygen inlet branch is also equipped with a first flow meter 13 and a pressure reducing valve 14 between the oxygen source 2 and the proportional valve 3 to ensure that the mixing ratio of oxygen and air reaches the optimal state.

[0039] The air entering the air compressor contains impurities and particulate matter. In order to protect the air compressor from damage, an air filter 15 is installed at the air intake end of the air intake branch. A second pressure sensor 16 and a second temperature sensor 17 are installed between the air filter 15 and the air compressor 4. A second flow meter 22 is also provided to monitor the air pressure, temperature and air flow at the air compressor inlet.

[0040] The injection device 6 is an ejector. The first inlet 61 is the nozzle of the ejector, and the second inlet 62 is the ejector port. As an injection device, the ejector uses a high-speed oxygen flow to eject a low-speed air flow, thereby achieving the mixing of oxygen and air.

[0041] The air outlet pipeline is also equipped with a third pressure sensor 18 and a third temperature sensor 19 to provide real-time data on the air pressure and temperature in the air outlet pipeline for system control and monitoring.

[0042] The outlet 72 of the water distributor 7 is connected to a drain pipe for discharging condensate from the water distributor to prevent water from entering the fuel cell stack and causing damage. A drain valve 20 is installed on the drain pipe to control the drainage process. A silencer 21 is installed downstream of the drain valve 20 on the drain pipe to reduce noise generated during the drainage process.

[0043] When this utility model is in use, during the operation of the fuel cell, high-pressure oxygen from oxygen source 2 is reduced in pressure by first flow meter 13 and pressure reducing valve 14 and then reaches proportional valve 3. Proportional valve 3 controls the flow rate of high-pressure oxygen entering injection device 6 by adjusting the opening size.

[0044] Air from the atmosphere passes through air filter 15, second pressure sensor 16, second temperature sensor 17, and second flow meter 22 in sequence to reach air compressor 4. After the air is pressurized, it enters injection device 6 through air inlet regulating valve 5.

[0045] The high-humidity gas from the fuel cell stack 1 enters the water separator 7 via the third temperature sensor 19 and the third pressure sensor 18. The water separator 7 separates the liquid water from the high-humidity gas from the fuel cell stack 1. The liquid water and some air enter the silencer 21 via the drain valve 20, while the humid air enters the injection device 6 via the return flow regulating valve 8.

[0046] The high-pressure pure oxygen, air and high-humidity air from the fuel cell stack enter the injection device 6 and then flow sequentially through the first pressure sensor 11, the first temperature sensor 12 and the regulating valve 10 before entering the fuel cell stack 1.

[0047] By acquiring the flow rate of the first flow meter 13, the second flow meter 22, the flow adjustment reflux regulating valve 8, the air inlet regulating valve 5, and the proportional valve 3 are used to maintain the air flow rate and humidity of the incoming stack within the set range.

Claims

1. A fuel cell cogeneration air supply system comprising a stack and an air intake line for supplying air to the stack, an air exhaust line for exhausting air from the stack, characterized by, The air inlet pipeline comprises: an air inlet main pipeline, the downstream end of which is connected to the stack; an oxygen inlet branch pipeline, which comprises, in sequence from upstream to downstream, an oxygen source and a proportional valve; an air inlet branch pipeline, which comprises, in sequence from upstream to downstream, an air compressor and an air inlet regulating valve; an injection device, which comprises a first inlet, a second inlet and an outlet, the first inlet being connected to the downstream end of the oxygen inlet branch pipeline, the second inlet being connected to the downstream end of the air inlet branch pipeline, and the outlet being connected to the upstream end of the air inlet main pipeline; the air outlet pipeline is connected to a water distributor, the water distributor comprising an air outlet and a water outlet, the air outlet being connected to the second inlet of the injection device through a backflow pipeline, and a backflow regulating valve being arranged on the backflow pipeline.

2. The fuel cell cogeneration air supply system according to claim 1, wherein The air inlet main pipeline is provided, in sequence from the upstream end to the downstream end, with a intercooler and a regulating valve.

3. The fuel cell cogeneration air supply system according to claim 2, wherein The air inlet main pipeline is further provided, between the intercooler and the regulating valve, with a first pressure sensor and a first temperature sensor.

4. The fuel cell cogeneration air supply system according to claim 1, wherein The oxygen inlet branch pipeline is further provided, between the oxygen source and the proportional valve, with a first flow meter and a pressure reducing valve.

5. The fuel cell cogeneration air supply system according to claim 1, wherein The air inlet branch pipeline is provided, at the air inlet end, with an air filter, and is further provided, between the air filter and the air compressor, with a second pressure sensor and a second temperature sensor.

6. The fuel cell cogeneration air supply system according to claim 1, wherein The injection device is an ejector, the first inlet is a nozzle port of the ejector, and the second inlet is an injection port of the ejector.

7. The fuel cell cogeneration air supply system according to claim 1, wherein The air outlet pipeline is provided with a third pressure sensor and a third temperature sensor.

8. The fuel cell cogeneration air supply system of claim 1, wherein The water outlet of the water distributor is connected to a water discharge pipeline, and a water discharge valve is arranged on the water discharge pipeline.

9. The fuel cell cogeneration air supply system of claim 8, wherein, The water discharge pipeline is provided, at the downstream end of the water discharge valve, with a silencer.

Images