Humidifier type fuel cell air supply and exhaust system for cogeneration device

Abstract

The invention discloses a humidifier type fuel cell air supply and exhaust system for a cogeneration device. An electric control three-way valve comprises an internal electric control mechanism, a first air inlet, a first air outlet and a second air outlet, wherein the first air inlet, the first air outlet and the second air outlet are arranged outside the electric control mechanism; the humidifier comprises a dry side inlet and a dry side outlet which correspond to each other, a wet side inlet and a wet side outlet which correspond to each other, the dry side inlet and the wet side outlet are located on the same side of the humidifier, the dry side outlet and the wet side inlet are located on the other side of the humidifier, and the dry side inlet and the dry side outlet are connected through a humidifier bypass valve outside the humidifier. The dry side outlet is connected with an electric pile air inlet of each electric pile air cavity, and an electric pile air outlet of each electric pile air cavity is connected with the wet side inlet. According to the invention, the active regulation and control of the actual air flow of each fuel cell stack can be realized, the air humidity of the stack air inlet of each stack can be regulated and controlled, the operability and durability of the working conditions of each fuel cell stack are considered, and the system is simple in structure and low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to an air supply and exhaust system for a fuel cell with a humidifier for a combined heat and power device. Background Art

[0002] In recent years, proton exchange membrane fuel cells (PEMFCs) have been gradually applied to combined heat and power (CHP) systems. For high-power centralized heating and power supply scenarios such as communities and factories, PEMFCs are moving from hundreds of kilowatts in the transportation sector to megawatts in the CHP sector. The most direct solution to increasing the power of PEMFCs is to combine multiple fuel cell stacks in series and parallel. The series-parallel combination of multiple fuel cell stacks for CHP systems involves redesigning the air supply and exhaust systems, hydrogen supply and circulation systems, coolant supply and circulation systems, and electrical systems. This differs from the design of systems composed of multiple fuel cell stacks in the transportation sector because the scale of fuel cell stacks varies by orders of magnitude. This requires consideration of both the operability and durability of individual fuel cell stacks under operating conditions, as well as the system complexity and cost of combining multiple fuel cell stacks.

[0003] In addition, at this stage, the membrane electrode, the core component of fuel cells, needs to maintain a high humidity to ensure sufficient durability of the membrane electrode. Therefore, the fuel cell air supply and exhaust system used in the combined heat and power device must be equipped with a humidifier to humidify the air entering the fuel cell stack. Since the ambient temperature and humidity of the combined heat and power device are constantly changing throughout the year, the humidification capacity of the humidifier must be appropriately adjusted according to the environmental conditions to ensure that the humidity of the membrane electrode is within a reasonable range. Therefore, it is necessary to study a fuel cell air supply and exhaust system with a humidifier for combined heat and power devices. Summary of the Invention

[0004] In order to overcome the above-mentioned problems, the purpose of the present invention is to provide a humidifier-type fuel cell air supply and exhaust system for a combined heat and power device, which can not only realize the active regulation of the actual air flow of each fuel cell stack, but also actively regulate the air humidity at the stack air inlet of each fuel cell stack, taking into account the operability and durability of the working conditions of each fuel cell stack, and the system structure is simple and the cost is low.

[0005] In order to achieve the above objectives, the technical solution adopted by the present invention is: a humidifier-type fuel cell air supply and exhaust system for a combined heat and power plant, wherein a plurality of fuel cell stacks are provided in the combined heat and power plant, including a flow resistance element, an air filter connected in sequence, an air flow thermometer, an air compressor, an air intercooler, an electrically controlled three-way valve and a humidifier; the electrically controlled three-way valve includes an internal electrical control mechanism and an external first air inlet, a first air outlet and a second air outlet, the air intercooler is connected to the first air inlet; the humidifier includes a corresponding dry side inlet and dry side outlet, a corresponding wet side inlet and wet side outlet, the dry side The inlet and the wet side outlet are located on the same side of the humidifier, the dry side outlet and the wet side inlet are located on the other side of the humidifier, the dry side inlet and the dry side outlet are connected outside the humidifier through a humidifier bypass valve, the wet side outlet is connected to the flow resistance element, and the first air outlet is connected to the dry side inlet; each of the fuel cell stacks is provided with a stack air cavity, and each of the stack air cavity includes a stack air inlet and a stack air outlet; the dry side outlet is connected to the stack air inlet of each of the stack air cavity, and the stack air outlet of each of the stack air cavity is connected to the wet side inlet.

[0006] Furthermore, the dry side outlet is provided with an inlet sealing valve, and the inlet sealing valve is connected to the stack air inlet of each stack air cavity.

[0007] The humidifier bypass valve outlet, the dry side outlet of the humidifier and the inlet sealing valve inlet are connected through a pipeline, and the inlet sealing valve outlet is connected to each of the fuel cell stack air inlets through a pipeline.

[0008] The inlet sealing valve is used to actively cut off the flow of working medium air between the inlet and outlet of the inlet sealing valve when the fuel cell stack stops working or is in other necessary working states. In other working states, the inlet sealing valve maintains the minimum flow resistance state as much as possible to reduce the air pressure at the outlet of the air compressor as much as possible.

[0009] Furthermore, the stack air outlet of each stack air cavity is respectively connected to a back pressure valve, and each back pressure valve is connected to the wet side inlet.

[0010] Each back-pressure valve inlet is connected to the stack air outlet of its respective stack air cavity. The back-pressure valve is used to adjust the flow resistance generated by the working medium air flowing through the back-pressure valve. The flow resistance of the working medium air flowing through each back-pressure valve is independently regulated.

[0011] Each back pressure valve outlet and the wet side inlet of the humidifier are connected through a pipeline.

[0012] Furthermore, a muffler is included, and the flow resistance element and the second air outlet are both connected to the muffler.

[0013] Furthermore, the air intercooler includes an air inlet, an air outlet, an air chamber between the air inlet and the air outlet, an external coolant inlet, an external coolant outlet, and a coolant chamber between the external coolant inlet and the air outlet. The air compressor is connected to the air inlet, and the air outlet is connected to the first air inlet of the electrically controlled three-way valve. The air intercooler is used to adjust the temperature of the working air. The working air and the external coolant only exchange heat within the air intercooler, which can either increase or decrease the working air temperature, depending on the respective temperatures of the working air and the external coolant.

[0014] Furthermore, a temperature sensor is provided between the electrically controlled three-way valve and the air intercooler, and the temperature sensor is used to measure the working medium air temperature at the outlet of the air intercooler.

[0015] Furthermore, a pressure sensor is provided between the first air outlet and the dry-side inlet for measuring the working medium air pressure at the first air outlet.

[0016] Furthermore, an inlet temperature sensor and an inlet pressure sensor are provided at the stack air inlet, and an outlet temperature sensor and an outlet pressure sensor are provided at the stack air outlet. The inlet temperature sensor is used to measure the working medium air temperature at the stack air inlet, and the inlet pressure sensor is used to measure the working medium air pressure at the stack air inlet. The outlet temperature sensor is used to measure the working medium air temperature at the stack air outlet, and the outlet pressure sensor is used to measure the working medium air pressure at the stack air outlet.

[0017] Furthermore, the humidifier is an air-to-air water vapor and heat exchange device. Dry-side air and wet-side air exchange water vapor and heat within the humidifier's inner cavity through special materials. Minimum penetration of dry-side air, except for water vapor, into the wet-side air is achieved, and vice versa. The working medium air at the wet-side inlet of the humidifier is the working medium air after the electrochemical reaction at the outlet of the fuel cell stack. This working medium air contains a large amount of water and exists in various phases, such as gaseous and liquid.

[0018] Furthermore, the humidifier bypass valve is an electrically controlled valve, which can actively adjust the flow resistance of the working medium air flowing through the humidifier bypass valve. By adjusting the flow resistance of the working medium air flowing through the humidifier bypass valve and the flow resistance of the working medium air entering the dry side of the humidifier, the distribution adjustment of the working medium air flow entering the dry side of the humidifier and the working medium air flow flowing through the humidifier bypass valve is achieved, thereby achieving adjustable and controllable humidity of the mixed working medium air formed after the humidified working medium air at the dry side outlet and the unhumidified working medium air flowing through the humidifier bypass valve converge.

[0019] Furthermore, it also includes a control module, which is used to collect feedback signals from the air flow thermometer, the temperature sensor, the pressure sensor, all the inlet temperature sensors, all the inlet pressure sensors, all the outlet temperature sensors and all the outlet pressure sensors, and implement coordinated control of the air compressor, the electronically controlled three-way valve, the humidifier bypass valve, the inlet sealing valve and all the back pressure valves according to the feedback signals and control targets. The control targets include the air flow and air pressure of the stack air inlet of each fuel cell stack.

[0020] The beneficial effects of the present invention are:

[0021] The present invention is provided with an air filter, an air flow thermometer, an air compressor, an air intercooler, an electrically controlled three-way valve and a humidifier. The dry side outlet of the humidifier is provided with an inlet sealing valve, which is connected to the stack air inlet of each stack air cavity. The stack air outlet of each stack air cavity is respectively connected to a back pressure valve, and each back pressure valve is connected to the wet side inlet of the humidifier. It can realize the active regulation of the actual air flow of each fuel cell stack and the active regulation of the air humidity of the stack air inlet of each fuel cell stack, taking into account the operability and durability of the working conditions of each fuel cell stack. The system structure is simple and the cost is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the structure of this embodiment;

[0023] Figure 2 Schematic diagram of the air cavity structure of the fuel cell stack of this embodiment.

[0024] In the figure: 1. Fuel cell stack air cavity; 2. Inlet temperature sensor; 3. Inlet pressure sensor; 4. Outlet temperature sensor; 5. Outlet pressure sensor; 6. Air filter; 7. Air flow thermometer; 8. Air compressor; 9. Air intercooler; 10. Electric three-way valve; 11. Humidifier; 12. Temperature sensor; 13. Pressure sensor; 14. Humidifier bypass valve; 15. Inlet sealing valve; 16. Back pressure valve; 17. Flow resistance element; 18. Muffler; 19. Control module. DETAILED DESCRIPTION

[0025] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0026] Example 1:

[0027] See also Figure 1-Figure 2 As shown, this embodiment discloses a humidifier-type fuel cell air supply and exhaust system for a combined heat and power device, including a control module 19, a flow resistance element 17, a muffler 18, an air filter 6, an air flow thermometer 7, an air compressor 8, an air intercooler 9, an electrically controlled three-way valve 10, and a humidifier 11 connected in sequence. The electrically controlled three-way valve 10 includes an internal electrical control mechanism and an external first air inlet, a first air outlet, and a second air outlet. The air intercooler 9 includes an air inlet, an air outlet, an air chamber between the air inlets and outlets, an external coolant inlet, an external coolant outlet, and a coolant chamber between the external coolant inlets and outlets. The air compressor 8 is connected to the air inlet, and the air outlet is connected to the first air inlet of the electrically controlled three-way valve 10. The air filtered by the air filter 6 is collectively referred to as working medium air.

[0028] The air intercooler 9 is used to adjust the working air temperature. The working air and the external coolant only exchange heat in the air intercooler 9, which can either increase or decrease the working air temperature, depending on the respective temperatures of the working air and the external coolant.

[0029] The electronic control mechanism is used to synchronously adjust the working medium air flow resistance between the first air inlet and the first air outlet, and between the first air inlet and the second air outlet. When the working medium air flow resistance between the first air inlet and the first air outlet increases, the working medium air flow resistance between the first air inlet and the second air outlet will inevitably decrease, and vice versa. The electrically controlled three-way valve 10 realizes the controllable diversion and distribution of the working medium air flow at the first air outlet and the second air outlet; the humidifier 11 includes a corresponding dry side inlet and dry side outlet, and a corresponding wet side inlet and wet side outlet. The dry side inlet and the wet side outlet are located on the same side of the humidifier 11, and the dry side outlet and the wet side inlet are located on the other side of the humidifier 11. The dry side inlet and the dry side outlet are connected outside the humidifier 11 through a humidifier bypass valve 14, and the wet side outlet is connected to a flow resistance element 17, and the flow resistance element 17 and the second air outlet are both connected to a muffler 18; the first air outlet is connected to the dry side inlet; a plurality of fuel cell stacks are provided in the cogeneration device, and each fuel cell stack is provided with a stack air cavity 1, and each stack air cavity 1 includes a stack air inlet and a stack air outlet; the dry side outlet is provided with an inlet sealing valve 15, and the inlet sealing valve 15 is connected to the stack air inlet of each stack air cavity 1. The stack air outlet of each stack air cavity 1 is connected to a back pressure valve 16 , and each back pressure valve 16 is connected to the wet side inlet.

[0030] The air filter 6 is used to filter out impurities such as particulate matter, CO, CO2, SO2, aromatic hydrocarbons, nitrogen oxides, etc. contained in the ambient air that affect the durability of the fuel cell stack and the normal operation of components.

[0031] The air flow thermometer 7 is used to measure the flow rate of the working medium air, usually the mass flow rate and temperature.

[0032] The air compressor 8 is used to perform work on the working medium air to increase the temperature, pressure and flow of the working medium air.

[0033] The outlet of the humidifier bypass valve 14, the dry side outlet of the humidifier 11 and the inlet of the inlet sealing valve 15 are connected through a pipeline, and the outlet of the inlet sealing valve 15 is connected to the air inlet of each fuel cell stack through a pipeline.

[0034] The inlet sealing valve 15 is used to actively cut off the flow of working medium air between the inlet and outlet of the inlet sealing valve 15 when the fuel cell stack stops working or is in other necessary working states. In other working states, the inlet sealing valve 15 maintains the minimum flow resistance state as much as possible to reduce the outlet air pressure of the air compressor 8 as much as possible.

[0035] The inlet of each back-pressure valve 16 is connected to the stack air outlet of its respective stack air cavity 1. The back-pressure valve 16 is used to adjust the flow resistance generated by the working air flowing through the back-pressure valve 16. The working air flow resistance flowing through each back-pressure valve 16 is independently regulated. When the working air flows through the flow resistance element 17, a preset working air flow resistance is generated, which is used to reduce the working air flow resistance borne by the back-pressure valve 16. The outlet of each back-pressure valve 16 and the wet-side inlet of the humidifier 11 are connected through a pipeline.

[0036] A temperature sensor 12 is provided between the electrically controlled three-way valve 10 and the air intercooler 9 to measure the working air temperature at the outlet of the air intercooler 9. A pressure sensor 13 is provided between the first air outlet and the dry side inlet to measure the working air pressure at the first air outlet.

[0037] An inlet temperature sensor 2 and an inlet pressure sensor 3 are installed at the stack air inlet, and an outlet temperature sensor 4 and an outlet pressure sensor 5 are installed at the stack air outlet. The inlet temperature sensor 2 measures the working air temperature at the stack air inlet, while the inlet pressure sensor 3 measures the working air pressure at the stack air inlet. The outlet temperature sensor 4 measures the working air temperature at the stack air outlet, while the outlet pressure sensor 5 measures the working air pressure at the stack air outlet.

[0038] Humidifier 11 is an air-to-air water vapor and heat exchange device. Dry-side air and wet-side air exchange water vapor and heat within the humidifier's inner cavity through special materials. Minimum penetration of dry-side air, except for water vapor, into the wet-side air is minimized, and vice versa. The working air at the wet-side inlet of humidifier 11 is the working air after the electrochemical reaction at the outlet of the fuel cell stack. This working air contains a large amount of water and exists in various phases, including gaseous and liquid.

[0039] The humidifier bypass valve 14 is an electrically controlled valve that can actively adjust the flow resistance of the working air flowing through the humidifier bypass valve 14. By adjusting the flow resistance of the working air flowing through the humidifier bypass valve 14 and the flow resistance of the working air entering the dry side of the humidifier 11, the distribution and adjustment of the working air flow entering the dry side of the humidifier 11 and the working air flow flowing through the humidifier bypass valve 14 are achieved, thereby achieving adjustable and controllable humidity of the mixed working air formed after the humidified working air at the dry side outlet and the unhumidified working air flowing through the humidifier bypass valve 14 converge.

[0040] The control module 19 is used to collect feedback signals from the air flow thermometer 7, temperature sensor 12, pressure sensor 13, all inlet temperature sensors 2, all inlet pressure sensors 3, all outlet temperature sensors 4 and all outlet pressure sensors 5, and implement coordinated control of the air compressor 8, electronically controlled three-way valve 10, humidifier bypass valve 14, inlet sealing valve 15, and all back pressure valves 16 according to the feedback signals and control targets. The control targets include the air flow and air pressure at the stack air inlet of each fuel cell stack.

[0041] The workflow of the present invention is:

[0042] After entering the air filter 6, the air sequentially enters the air flow thermometer 7, the air compressor 8, the air intercooler 9, the electronically controlled three-way valve 10, and the humidifier 11. The air filtered by the air filter 6 is collectively referred to as working air. The working air from the air intercooler 9 enters the electronically controlled three-way valve 10 through the first air inlet, and then the working air from the first air outlet enters the humidifier 11 through the dry side inlet. The working air from the second air outlet of the electronically controlled three-way valve 10 enters the muffler 18 and is then discharged into the environment.

[0043] The working medium air coming out of the dry side outlet of the humidifier 11 enters the inlet sealing valve 15 and then enters the stack air inlet of each stack air cavity 1, and then enters the stack air cavity 1 of each fuel cell stack;

[0044] Then, the working medium air coming out of the stack air outlet of each stack air cavity 1 passes through the respective back pressure valves 16 and enters the wet side inlet of the humidifier 11;

[0045] The working medium air coming out of the wet side outlet of the humidifier 11 enters the flow resistance element 17 and then enters the muffler 18 and is discharged into the environment.

[0046] The present invention is provided with an air filter 6, an air flow thermometer 7, an air compressor 8, an air intercooler 9, an electrically controlled three-way valve 10 and a humidifier 11. The dry side outlet of the humidifier 11 is provided with an inlet sealing valve 15, which is connected to the stack air inlet of each stack air cavity. The stack air outlet of each stack air cavity is respectively connected to a back pressure valve 16, and each back pressure valve 16 is connected to the wet side inlet of the humidifier 11. It can not only realize the active regulation of the actual air flow of each fuel cell stack, but also actively regulate the air humidity of the stack air inlet of each fuel cell stack, taking into account the operability and durability of the working conditions of each fuel cell stack. The system structure is simple and the cost is low.

[0047] The above embodiments are only for illustrating the technical concept and features of the present invention. Its purpose is to enable people familiar with this technology to understand the content of the present invention and implement it. It cannot be used to limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A humidifier-type fuel cell air supply and exhaust system for a combined heat and power plant, wherein the combined heat and power plant is provided with a plurality of fuel cell stacks, characterized in that: The invention comprises a flow resistance element (17), an air filter (6), an air flow thermometer (7), an air compressor (8), an air intercooler (9), an electric control three-way valve (10) and a humidifier (11) connected in sequence; the electric control three-way valve (10) comprises an internal electric control mechanism and an external first air inlet, a first air outlet and a second air outlet, the air intercooler (9) is connected to the first air inlet; the humidifier (11) comprises a corresponding dry side inlet and dry side outlet, a corresponding wet side inlet and wet side outlet, the dry side The inlet and the wet side outlet are located on the same side of the humidifier (11), the dry side outlet and the wet side inlet are located on the other side of the humidifier (11), the dry side inlet and the dry side outlet are connected outside the humidifier (11) through a humidifier bypass valve (14), the wet side outlet is connected to the flow resistance element (17), and the first air outlet is connected to the dry side inlet; each fuel cell stack is provided with a stack air cavity (1), and each stack air cavity (1) includes a stack air inlet and a stack air outlet; The dry side outlet is connected to the stack air inlet of each stack air cavity (1), and the stack air outlet of each stack air cavity (1) is connected to the wet side inlet.

2. The air supply and exhaust system for a fuel cell with a humidifier for a combined heat and power device according to claim 1, characterized in that: The dry side outlet is provided with an inlet sealing valve (15), and the inlet sealing valve (15) is connected to the stack air inlet of each stack air cavity (1).

3. The air supply and exhaust system for a fuel cell with a humidifier for a combined heat and power device according to claim 2, characterized in that: The stack air outlet of each stack air cavity (1) is connected to a back pressure valve (16), and each back pressure valve (16) is connected to the wet side inlet.

4. The air supply and exhaust system for a fuel cell with a humidifier for a combined heat and power device according to claim 3, characterized in that: It also includes a muffler (18), and the flow resistance element (17) and the second air outlet are both connected to the muffler (18).

5. The air supply and exhaust system for a fuel cell with a humidifier for a combined heat and power device according to claim 4, characterized in that: The air intercooler (9) comprises an air inlet, an air outlet, an air cavity between the air inlet and the air outlet, an external coolant inlet, an external coolant outlet, and a coolant cavity between the external coolant inlet and the air outlet; the air compressor (8) is connected to the air inlet, and the air outlet is connected to the first air inlet of the electric-controlled three-way valve (10).

6. The fuel cell air supply and exhaust system with a humidifier for a combined heat and power device according to claim 5, characterized in that: A temperature sensor (12) is provided between the electrically controlled three-way valve (10) and the air intercooler (9).

7. The fuel cell air supply and exhaust system with a humidifier for a combined heat and power device according to claim 6, characterized in that: A pressure sensor (13) is provided between the first air outlet and the dry side inlet.

8. The fuel cell air supply and exhaust system with a humidifier for a combined heat and power device according to claim 7, characterized in that: An inlet temperature sensor (2) and an inlet pressure sensor (3) are provided at the air inlet of the stack, and an outlet temperature sensor (4) and an outlet pressure sensor (5) are provided at the air outlet of the stack.

9. The fuel cell air supply and exhaust system with a humidifier for a combined heat and power device according to claim 8, characterized in that: The humidifier (11) is a gas-to-gas water vapor and heat exchange device.

10. The fuel cell air supply and exhaust system with a humidifier for a combined heat and power device according to claim 9, characterized in that: The invention also includes a control module (19), which is used to collect feedback signals from the air flow thermometer (7), the temperature sensor (12), the pressure sensor (13), all the inlet temperature sensors (2), all the inlet pressure sensors (3), all the outlet temperature sensors (4) and all the outlet pressure sensors (5), and implement coordinated control of the air compressor (8), the electric-controlled three-way valve (10), the humidifier bypass valve (14), the inlet sealing valve (15) and all the back pressure valves (16) according to the feedback signals and control targets, wherein the control targets include the air flow and air pressure of the stack air inlet of each fuel cell stack.

Images