A system and method for adjusting the dew point temperature of a gas

Abstract

A system and method for adjusting the dew point temperature of a gas, relating to the field of fuel cells, to solve the problem of how to improve the efficiency of high and low dew point adjustment in a fuel cell test system; it includes a gas filtration unit, a flow control unit, a switching unit, a humidification unit, a mixing unit, and a temperature control unit; among them, the switching unit includes three gas paths: a dry gas branch, a wet gas branch, and a dry-wet switching branch, and the dry-wet switching branch can be flexibly switched between the dry gas branch and the wet gas branch; the present invention adjusts the dew point temperature of the gas entering the fuel cell stack by controlling the flow ratio of the dry gas and the gas entering the humidification tank, and realizes the rapid distribution of the flow rates of the dry gas and the wet gas in the fuel cell test system by using a three-way valve, improving the utilization rate of system components and reducing the occupied space size, greatly improving the use efficiency of the equipment and reducing the cost of the system.

Description

Technical Field

[0001] The present invention belongs to the field of fuel cells and relates to a system and method for adjusting the dew point temperature of a gas. Background Art

[0002] Fuel cells are the fourth-generation power generation technology after nuclear energy. They can directly convert chemical energy into electrical energy, are not affected by the Carnot cycle, and have the characteristics of high efficiency and cleanliness. Proton exchange membrane fuel cells need to humidify the fuel due to the special nature of their membranes to improve their power generation efficiency. A fuel cell test system is a device for evaluating and testing the performance of fuel cells and is used in the development and testing of fuel cells.

[0003] During the development and testing of fuel cells, it is necessary to simulate various operating environments and condition parameters. High dynamic response and efficient humidification control are the keys to accurate test evaluation. While the test system provides a suitable working environment for the fuel cell, its dew point switching speed under different conditions is particularly important for evaluating the response speed of the fuel cell and its operation under variable conditions.

[0004] In current fuel cell test systems, the humidification technologies are mostly bubbling humidification and spray humidification. Among them, due to the heat capacity of the humidifying water in bubbling humidification, the response to the set temperature is slow and cannot meet the requirement of rapid humidification. And there are small droplets in the gas after spray humidification, which affects the humidification effect. Adjusting the heating power by measuring the temperature of the heating plate may cause incomplete evaporation of the water mist or overheating of the moisture, and fluctuations in the water flow rate and the power of the heating tube during the adjustment process will cause large changes in humidity. Therefore, the response speed of these two humidification methods to dew point switching is slow and cannot achieve high dynamic adjustment. A new method for quickly adjusting the dew point is needed.

[0005] The invention patent application with the application publication number CN109361002A proposes a humidifier for a high-power fuel cell test bench, which discloses a humidifier for a high-power fuel cell test bench, including a bubbling humidification area, a spray humidification area located above the bubbling humidification area, and a water storage area located below the bubbling humidification area. There is a space between the bubbling humidification area and the spray humidification area. A gas inlet is provided at the lower part of the bubbling humidification area, a gas outlet and a deionized water inlet are provided at the top of the spray humidification area, and a deionized water outlet is provided at the bottom of the water storage area. The deionized water inlet and the deionized water outlet are connected through an external pipeline. This invention combines bubbling humidification and spray humidification, can achieve a good humidification effect, and the high specific surface area filler in the spray humidification area can achieve efficient humidification and prevent liquid water from entering the fuel cell. However, due to the heat capacity of water, it is impossible to achieve high dynamic response when the dew point temperature drops from a high value to a low value.

[0006] The invention patent application with the publication number of CN116598537A discloses a method for quickly controlling the relative humidity of a fuel cell, which includes controlling the different flow rates of dry gas and wet gas through hydrogen / air flow control, controlling the dew point temperature of the wet gas, and mixing dry and wet gases in different proportions to quickly adjust the humidity of hydrogen / air entering the stack. At the same time, the temperature of the gas entering the stack is controlled to achieve a quick adjustment of the gas humidity. By controlling the different flow rates of dry gas and wet gas through hydrogen / air flow control, the dew point temperature of the wet gas and the temperature of the gas entering the stack can also be displayed and controlled by various measuring instruments, so as to quickly and accurately adjust the gas humidity to meet the engineering requirements. However, this method requires setting the same number of flow controllers on the dry gas and wet gas sides, resulting in a high cost.

[0007] In the existing fuel cell test system, humidification is often carried out by bubbling or spraying, and the following problems mainly exist: (1) When switching the dew point state of the gas, the response speed is slow; (2) In the existing test system with a quick humidity switching function, an additional method of adding multiple flow controllers is often adopted to achieve it; (3) The gas flow control in the existing fuel cell test system is a mass flow controller, and its cost is high; (4) Adjusting the dew point temperature by raising and lowering the water temperature in the humidification tank in the existing fuel cell test system will cause waste of energy and increase the system energy consumption. Summary of the Invention

[0008] The technical problem to be solved by the present invention is how to improve the efficiency of adjusting the high and low dew points of the fuel cell test system.

[0009] The present invention solves the above technical problems through the following technical solutions:

[0010] A system for adjusting the dew point temperature of a gas includes a gas filtration unit, a flow control unit, a switching unit, a humidification unit, a mixing unit, and a temperature control unit; the gas filtration unit, the flow control unit, the switching unit, the mixing unit, and the temperature control unit are connected in sequence, and the connection between the switching unit and the mixing unit is divided into two paths. One path is that the switching unit is directly connected to the mixing unit, and the other path also includes a humidification unit. The switching unit is first connected to the humidification unit, and the humidification unit is then connected to the mixing unit;

[0011] The gas filtration unit filters the input gas, the flow control unit controls the size of the input gas flow, and the switching unit regulates the output gas to be dry gas, wet gas, or a dry-wet mixture according to the gas volume demand; the gas enters the temperature control unit, and the temperature control unit heats the gas and then outputs the gas with the dew point temperature and temperature that meet the engineering requirements.

[0012] A system and method for adjusting the dew point temperature of a gas according to the present invention adopt multiple gas paths, namely a dry gas branch, a wet gas branch, and a dry-wet switching branch. By using a three-way valve, the flow rates of the dry gas and the wet gas in the fuel cell test system can be quickly distributed, improving the utilization rate of system components and reducing the occupied space. The operating efficiency of the equipment is greatly improved, and the system cost is reduced. Moreover, without changing the water temperature of the humidifying box, only the intake air volumes of the dry and wet paths need to be controlled and adjusted to complete the operation, accelerating the switching speed of the gas at high and low dew points, with a fast response speed, reducing the energy consumption of the system, and having a relatively low equipment cost.

[0013] Preferably, the flow control unit includes a first proportional valve 31, a second proportional valve 32, a third proportional valve 33, a fourth proportional valve 34, a first flow meter 35, a second flow meter 36, a third flow meter 37, and a fourth flow meter 38. One end of the first proportional valve 31, one end of the second proportional valve 32, one end of the third proportional valve 33, and one end of the fourth proportional valve 34 are connected to the gas filtering unit. The other end of the first proportional valve 31 is connected to one end of the first flow meter 35, the other end of the second proportional valve 32 is connected to one end of the second flow meter 36, the other end of the third proportional valve 33 is connected to one end of the third flow meter 37, the other end of the fourth proportional valve 34 is connected to one end of the fourth flow meter 38, and the other ends of the first flow meter 35, the second flow meter 36, the third flow meter 37, and the fourth flow meter 38 are connected to the switching unit.

[0014] Advantageous effects: By using the method of combining a proportional valve and a flow meter for gas flow monitoring, the cost is low, and it is applicable to a low-cost test system for high-power fuel cells. At the same time, by controlling the flow rate ratio of the dry gas and the gas entering the humidifying box through the method of combining a proportional valve and a flow meter to adjust the dew point temperature of the gas entering the fuel cell, without changing the water temperature of the humidifying box, the switching speed of the gas at high and low dew points is accelerated, the response speed is fast, the energy consumption of the system is reduced, and the equipment cost is further reduced.

[0015] Preferably, the flow control unit includes a first flow controller 3, a second flow controller 4, a third flow controller 5, and a fourth flow controller 6. One end of the first flow controller 3, one end of the second flow controller 4, one end of the third flow controller 5, and one end of the fourth flow controller 6 are connected to the gas filtering unit. The other ends of the first flow controller 3, the second flow controller 4, the third flow controller 5, and the fourth flow controller 6 are connected to the switching unit.

[0016] Advantageous effects: By monitoring the gas flow through the flow controller and controlling the flow rate ratio of the dry gas and the gas entering the humidifying box to adjust the dew point temperature of the gas entering the fuel cell, without changing the water temperature of the humidifying box, the switching speed of the gas at high and low dew points is accelerated, the response speed is fast, the energy consumption of the system is reduced, and the equipment cost is further reduced.

[0017] Preferably, the switching unit includes a first three-way valve 7 and a second three-way valve 8; the input end of the first three-way valve 7 is connected to the other end of the second flowmeter 36, the input end of the second three-way valve 8 is connected to the other end of the third flowmeter 37, one output end of the first three-way valve 7 and one output end of the second three-way valve 8 are connected together and connected to the other end of the first flowmeter 35 and then access the mixing unit, and the other output end of the first three-way valve 7 and the other output end of the second three-way valve 8 are connected together and connected to the other end of the fourth flowmeter 38 and then access the humidifying unit.

[0018] Preferably, the switching unit includes a first three-way valve 7 and a second three-way valve 8; the input end of the first three-way valve 7 is connected to the other end of the second flow controller 4, the input end of the second three-way valve 8 is connected to the other end of the third flow controller 5, one output end of the first three-way valve 7 and one output end of the second three-way valve 8 are connected together and connected to the other end of the first flow controller 3 and then access the mixing unit, and the other output end of the first three-way valve 7 and the other output end of the second three-way valve 8 are connected together and connected to the other end of the fourth flow controller 6 and then access the humidifying unit.

[0019] Preferably, the humidifying unit includes a second check valve 10, a second pressure sensor 11, a humidifier, a water replenishing valve 12, a third check valve 13, a drain valve 14, a second temperature sensor 17, and a fourth pressure sensor 18; one end of the second check valve 10 is connected to the moisture branch of the switching unit, the other end of the second check valve 10 is connected to one end of the second pressure sensor 11, the other end of the second pressure sensor 11 is connected to the input end of the humidifier, the humidifier also has a water replenishing end and a drain end, the water replenishing valve 12 is connected to one end of the third check valve 13, the other end of the third check valve 13 is connected to the water replenishing end of the humidifier, the drain end of the humidifier is connected to the drain valve 14, the output end of the humidifier is connected to one end of the second temperature sensor 17, the other end of the second temperature sensor 17 is connected to one end of the fourth pressure sensor 18, and the other end of the fourth pressure sensor 18 is connected to the mixing unit.

[0020] Preferably, the humidifying unit further includes a third pressure sensor 15 and a first temperature sensor 16, and the third pressure sensor 15 and the first temperature sensor 16 are installed on the side wall of the humidifier.

[0021] A method for using a system for adjusting the dew point temperature of a gas includes the following steps:

[0022] Step 1, input a gas, and the gas filtration unit filters the input gas;

[0023] Step 2: The gas enters the flow control unit, and the size of the input gas flow is controlled by setting the flow unit.

[0024] Step 3: The gas enters the switching unit. The switching unit regulates the output gas to be dry gas, wet gas, or a mixture of dry and wet according to the gas volume requirement. The switching unit flexibly regulates the output gas according to the dry gas or wet gas volume requirement.

[0025] Step 4: The gas enters the temperature control unit. The temperature control unit heats the gas and then outputs the gas with the dew point temperature and temperature meeting the engineering requirements.

[0026] Preferably, step 3 further includes

[0027] Step 31: When there are differences between both the dry gas and the wet gas and the gas dew point temperature value required for system testing, the dry gas and the wet gas are simultaneously ventilated for operation. At this time, there is a direct connection between the switching unit and the mixing unit, and at the same time, the switching unit is connected to the mixing unit through the humidifying unit. The switching unit flexibly regulates the output according to the dry gas or wet gas volume requirement.

[0028] Step 32: When the wet gas meets the gas dew point temperature requirement but the gas dew point temperature still does not meet the requirement, the input of the dry gas is stopped, and only the wet gas is output. At this time, there is no connection between the switching unit and the mixing unit, and the switching unit is connected to the mixing unit through the humidifying unit. The switching unit flexibly regulates the output of the gas passing through the humidifying unit according to the wet gas volume requirement.

[0029] Step 33: When the dry gas meets the gas dew point temperature requirement but the gas dew point temperature still does not meet the requirement, the input of the wet gas is stopped, and only the dry gas is output. At this time, there is a direct connection between the switching unit and the mixing unit, and the switching unit is not connected to the humidifying unit. The switching unit flexibly regulates the output according to the dry gas volume requirement.

[0030] A fuel cell system of a system for regulating the gas dew point temperature, characterized in that it further includes a stack, an exhaust gas cooling unit, a pressure control unit, and a gas-liquid separation unit connected in sequence after the temperature control unit;

[0031] It further includes a detection unit before and after entering the stack. One end of the detection unit before and after entering the stack is located between the connection lines of the temperature control unit and the stack, and the other end of the detection unit before and after entering the stack is located between the connection lines of the stack and the exhaust gas cooling unit;

[0032] The front and rear detection unit of the incoming power stack includes a sixth pressure sensor 23, a fourth temperature sensor 24, a dew point sensor 25, a seventh pressure sensor 26, and a fifth temperature sensor 27; one end of the sixth pressure sensor 23 is connected to the temperature control unit, the other end of the sixth pressure sensor 23 is connected to one end of the fourth temperature sensor 24, the other end of the fourth temperature sensor 24 is connected to one end of the dew point sensor 25, the other end of the dew point sensor 25 is connected to one end of the power stack, the other end of the power stack is connected to one end of the seventh pressure sensor 26, the other end of the seventh pressure sensor 26 is connected to one end of the fifth temperature sensor 27, and the other end of the fifth temperature sensor 27 is connected to the tail row cooling unit. Description of the Drawings

[0033] Figure 1 is the structural schematic diagram of a system for adjusting the dew point temperature of gas in Embodiment 1 of the present invention;

[0034] Figure 2 is the connection structure diagram of a system for adjusting the dew point temperature of gas in Embodiment 1 of the present invention;

[0035] Figure 3 is the connection structure diagram of a system for adjusting the dew point temperature of gas in Embodiment 2 of the present invention;

[0036] Figure 4 is the structural schematic diagram of a system for adjusting the dew point temperature of gas in Embodiment 3 of the present invention;

[0037] Figure 5 is the fuel cell system connection structure diagram of a system for adjusting the dew point temperature of gas in Embodiment 3 of the present invention;

[0038] Figure 6 is the fuel cell system connection structure diagram of a system for adjusting the dew point temperature of gas in Embodiment 4 of the present invention.

[0039] Reference numerals in the figure: filter 1, first pressure sensor 2, first flow controller 3, second flow controller 4, third flow controller 5, fourth flow controller 6, first three-way valve 7, second three-way valve 8, first check valve 9, second check valve 10, second pressure sensor 11, make-up water valve 12, third check valve 13, drain valve 14, third pressure sensor 15, first temperature sensor 16, second temperature sensor 17, fourth pressure sensor 18, fourth check valve 19, fifth pressure sensor 20, third temperature sensor 21, heater 22, sixth pressure sensor 23, fourth temperature sensor 24, dew point sensor 25, seventh pressure sensor 26, fifth temperature sensor 27, heat exchanger 28, back pressure valve 29, tail exhaust port 30, first proportional valve 31, second proportional valve 32, third proportional valve 33, fourth proportional valve 34, first flow meter 35, second flow meter 36, third flow meter 37, fourth flow meter 38. Detailed implementation manners

[0040] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings of the specification and specific embodiments:

[0042] Embodiment 1

[0043] As Figure 1 shown, it is a structural schematic diagram of a system for adjusting the dew point temperature of a gas according to Embodiment 1 of the present invention; a system for adjusting the dew point temperature of a gas according to the present invention includes a gas filtration unit, a flow control unit, a switching unit, a humidification unit, a mixing unit, and a temperature control unit; the gas filtration unit, the flow control unit, the switching unit, the humidification unit, the mixing unit, and the temperature control unit are connected in sequence, wherein the switching unit outputs the gas into two paths, one is a dry gas branch directly connected to the input end of the mixing unit, and the other is a wet gas branch including the humidification unit. The gas is first humidified by the humidification unit and then input into the mixing unit for mixing. The output end of the mixing unit is connected to the temperature control unit.

[0044] As Figure 2As shown in the figure, it is a system connection structure diagram for adjusting the dew point temperature of a gas according to Embodiment 1 of the present invention; the gas filtration unit includes a filter 1 and a first pressure sensor 2; the flow control unit includes a first proportional valve 31, a second proportional valve 32, a third proportional valve 33, a fourth proportional valve 34, a first flowmeter 35, a second flowmeter 36, a third flowmeter 37, and a fourth flowmeter 38; the switching unit includes a first three-way valve 7 and a second three-way valve 8; the humidification unit includes a second check valve 10, a second pressure sensor 11, a humidifier, a makeup water valve 12, a third check valve 13, a drain valve 14, a third pressure sensor 15, a first temperature sensor 16, a second temperature sensor 17, and a fourth pressure sensor 18; the mixing unit includes a first check valve 9, a fourth check valve 19, a fifth pressure sensor 20, and a third temperature sensor 21; the temperature control unit includes a heater 22.

[0045] The hydrogen / air enters the system through one end of the filter 1, the other end of the filter 1 is connected to one end of the first pressure sensor 2, the other end of the first pressure sensor 2 is connected to one end of the first proportional valve 31, one end of the second proportional valve 32, one end of the third proportional valve 33, and one end of the fourth proportional valve 34. The other end of the first proportional valve 31 is connected to one end of the first flowmeter 35, the other end of the second proportional valve 32 is connected to one end of the second flowmeter 36, the other end of the third proportional valve 33 is connected to one end of the third flowmeter 37, and the other end of the fourth proportional valve 34 is connected to one end of the fourth flowmeter 38. The other end of the first flowmeter 35 is connected to one of the output ends of the first three-way valve 7, one of the output ends of the second three-way valve 8, and the input end of the first check valve 9. The other end of the second flowmeter 36 is connected to the input end of the first three-way valve 7. The other end of the third flowmeter 37 is connected to the input end of the second three-way valve 8. The other end of the fourth flowmeter 38 is connected to the other output end of the first three-way valve 7 and the other output end of the second three-way valve 8 and is connected together to the input end of the second check valve 10. The output end of the first check valve 9 is connected to the output end of the fourth check valve 19 and one end of the fifth pressure sensor 20. The output end of the second check valve 10 is connected to one end of the second pressure sensor 11. The other end of the second pressure sensor 11 is connected to the input end of the humidifier. The humidifier also has a makeup water end and a drain end. The makeup water is connected to the input end of the third check valve 13 through the makeup water valve 12. The output end of the third check valve 13 is connected to the makeup water end of the humidifier. The humidifier drains water through the drain end and is discharged through the drain valve 14. The humidifier is also provided with a third pressure sensor 15 and a first temperature sensor 16. The third pressure sensor 15 and the first temperature sensor 16 are installed on the lower side wall of the humidifier. The output end of the humidifier is sequentially connected to the second temperature sensor 17, the fourth pressure sensor 18, and the input end of the fourth check valve 19. The other end of the fifth pressure sensor 20 is connected to the third temperature sensor 21 and then connected to the heater 22.

[0046] The filter 1 described in this embodiment is located at the front end of a number of proportional valves plus flow meters, and is used to filter hydrogen or air to protect the flow meters; the first pressure sensor 2 is located at the rear end of the filter 1 and is used to monitor the pressure of hydrogen or air before entering the proportional valve.

[0047] The first proportional valve 31, the second proportional valve 32, the third proportional valve 33, and the fourth proportional valve 34 are pneumatic proportional valves, electromagnetic proportional valves, electric proportional valves, or electro-hydraulic proportional valves. In this embodiment, the electromagnetic proportional valve is preferably used.

[0048] The first flow meter 35, the second flow meter 36, the third flow meter 37, and the fourth flow meter 38 connected to the rear ends of the first proportional valve 31, the second proportional valve 32, the third proportional valve 33, and the fourth proportional valve 34 are used to detect the gas flow rate, and the opening degrees of the first proportional valve 31 and the second proportional valve 32 at the front end are used for PID adjustment to control the input of the gas flow rate; at the same time, the flow directions of the outlets of the second flow meter 36 and the third flow meter 37 are switched and controlled by a three-way valve. When there are differences between the dry gas and the wet gas from the dew point temperature value required for system testing, in order to improve the gas input efficiency, the dry gas and the wet gas are simultaneously ventilated for operation, that is, there is a direct connection between the switching unit and the mixing unit, and at the same time, the switching unit is connected to the mixing unit through the humidifying unit. At this time, the switching unit flexibly adjusts the output according to the demand of the dry gas or wet gas volume; when the gas required for system testing does not need to be humidified, the input of the wet gas is stopped, and only the dry gas is output, that is, there is a direct connection between the switching unit and the mixing unit, and the switching unit is not connected to the humidifying unit; when the dew point temperature of the wet gas at this time meets the dew point temperature of the gas required for system testing, the input of the dry gas is stopped, and only the wet gas is input, that is, there is no connection between the switching unit and the mixing unit, and the switching unit is connected to the mixing unit through the humidifying unit.

[0049] Preferably, the three-way valve is a pneumatic valve or an electric valve, and the flow capacity in different directions is the same, without dead zones.

[0050] The first check valve 9 is located in the dry gas branch to prevent gas backflow.

[0051] The second check valve 10 is located in the pipeline before the gas enters the humidifier to prevent water from entering the flow meter and causing damage.

[0052] The humidifier can be bubble humidification, spray humidification, bubble plus spray humidification, steam humidification, etc. In this embodiment, bubble plus spray humidification is preferably selected.

[0053] The water replenishing valve 12 can be a manual valve, an electric valve, a pneumatically controlled valve, a solenoid valve, etc. In this embodiment, an electric valve or a solenoid valve is preferably used.

[0054] The third check valve 13 is located at the rear end of the water replenishing valve 12 to prevent damage to the front-end valve caused by water pressure impact.

[0055] Preferably, the humidifier in this embodiment includes a bubble spraying device, a liquid level sensor, a third pressure sensor 15, a first temperature sensor 16, etc. The sensors are respectively used to detect the liquid level, pressure and temperature. In addition, the top of the humidifier is also equipped with a safety relief valve to prevent the pressure difference between the inside and outside of the humidifier from being too large.

[0056] The second temperature sensor 17 and the fourth pressure sensor 18 are located at the outlet of the humidifier and are used to detect the outlet gas and pressure. At the same time, the second temperature sensor 17 can replace the dew point temperature sensor for monitoring the dew point temperature. When the second temperature sensor 17 detects that the dew point temperature reaches the required value of the test, the input of the dry gas gas path will be closed, and only the wet gas branch will work until the required dry gas demand for the test is met.

[0057] The fourth check valve 19 is located at the rear end of the fourth pressure sensor 18 and the front end of the dry-wet gas mixture, and is used to prevent dry gas from entering the humidifier.

[0058] The fifth pressure sensor 20 and the third temperature sensor 21 are located at the front end of the heater 22 and are used to monitor the pressure and temperature of the gas before entering the heater.

[0059] Preferably, the heater 22 can be an electric heater, a plate heat exchanger, etc. The heater 22 heats the gas to the temperature required for the test according to the test needs.

[0060] Embodiment 2

[0061] As Figure 3 shown, it is a flowchart of a system for adjusting the dew point temperature of a gas according to Embodiment 2 of the present invention. The difference between this Embodiment 2 and Embodiment 1 is that the flow control unit in this Embodiment 2 includes a first flow controller 3, a second flow controller 4, a third flow controller 5, and a fourth flow controller 6. One end of the first flow controller 3, one end of the second flow controller 4, one end of the third flow controller 5, and one end of the fourth flow controller 6 are connected to the other end of the first pressure sensor 2. The other end of the first flow controller 3 is connected to one output end of the first three-way valve 7, one output end of the second three-way valve 8, and the input end of the first check valve 9. The other end of the second flow controller 4 is connected to the input end of the first three-way valve 7. The other end of the third flow controller 5 is connected to the input end of the second three-way valve 8. The other end of the fourth flow controller 6 is connected to the other output end of the first three-way valve 7 and the other output end of the second three-way valve 8 and is connected together to the input end of the second check valve 10.

[0062] In the second embodiment, a number of flow controllers are connected in parallel. On the basis of meeting the maximum flow rate, an additional dry gas flow controller is added. Preferably, the first flow controller 3 is the dry gas flow controller, and the second flow controller 4, the third flow controller 5, and the fourth flow controller 6 are defaulted to wet gas flow controllers.

[0063] Preferably, the flow controller adopts a mass flow controller, which can control the gas flow more precisely.

[0064] The outlet flow directions of the second flow controller 4 and the third flow controller 5 are controlled by a three-way valve.

[0065] Here, the dew point temperature is described as follows: When the water vapor content in the air remains unchanged and the air pressure is kept constant, the temperature at which the air cools to saturation is called the dew point temperature. In the present invention, the water vapor content per unit gas flow rate ( ) and the gas flow rate ( ) are calculated based on the set dew point temperature ( ) and pressure ( ). The temperature at the outlet of the humidifying box can be considered as the dew point temperature of the wet gas branch ( ), from which the water vapor content per unit gas flow rate can be obtained, and then the gas flow rate of the wet gas can be obtained , and then the dry gas flow rate can be determined, so as to determine the dry gas flow rate required for the test.

[0066] When the system works, the dry gas branch and the wet gas branch work simultaneously. After determining the required gas dew point temperature and gas flow rate for the test, according to the calculated dry gas and wet gas flow rates, the wet gas branch is opened and the gas in the wet gas branch is humidified by the humidifier (the default flow direction of the three-way switching valve is the wet gas). The humidifier keeps humidifying until the water vapor content of the gas required for the required gas dew point temperature of the project is obtained. At the same time, according to the calculated dry gas flow rate, the dry and wet gases are mixed in the mixing unit to reach the dew point temperature of the target gas.

[0067] When the calculated dry gas flow rate exceeds the maximum range of a single flow controller, the first three-way valve 7 starts to act and switches from the wet gas branch to the dry gas branch; if two dry gas flow controllers cannot meet the dry gas flow rate, the second three-way valve 8 starts to act and switches from the wet gas branch to the dry gas branch until the required gas dew point temperature of the system is reached.

[0068] When the gas dew point temperature required for subsequent tests changes, the required wet gas flow rate and dry gas flow rate are determined again according to the changed gas dew point temperature, and then the above process can be repeated. There is no need to change the temperature of the humidifier water temperature. Only the intake air volume of the dry and wet paths needs to be controlled and adjusted to complete. And because there is no need to change the water temperature of the humidification chamber, the energy consumption of the system is reduced, the switching speed of the gas at high and low dew points is accelerated, and the response speed is fast. The switching of the three-way valve is used to quickly distribute the dry gas and wet gas flow rates in the fuel cell test system, improve the utilization rate of system components, and reduce the occupied space size, greatly improving the use efficiency of the equipment.

[0069] Similarly, in Embodiment 1, when the flow controller is replaced with a combination of a proportional valve and a flow meter, the gas flow rate is controlled by controlling the opening degree of the proportional valve, and the switching principle of the dry and wet gases is the same as above.

[0070] Embodiment 3

[0071] As Figure 4 shown, it is the structural schematic diagram of the fuel cell system of a system for adjusting the gas dew point temperature according to Embodiment 3 of the present invention; Embodiment 3 is a specific application of Embodiment 1. An electric stack, an exhaust gas cooling unit, a pressure control unit, and a gas-liquid separation unit are sequentially added after the temperature control unit in Embodiment 1. It also includes a detection unit before and after entering the electric stack. One end of the detection unit before and after entering the electric stack is located between the connection lines of the temperature control unit and the electric stack, and the other end of the detection unit before and after entering the electric stack is located between the connection lines of the electric stack and the exhaust gas cooling unit.

[0072] As Figure 5 shown, it is the connection structure diagram of the fuel cell system of a system for adjusting the gas dew point temperature according to Embodiment 3 of the present invention; the electric stack is a battery stack composed of multiple fuel cells, hereinafter simply referred to as a fuel cell stack; the detection unit before entering the fuel cell stack includes a sixth pressure sensor 23, a fourth temperature sensor 24, and a dew point sensor 25, and the post-detection unit includes a seventh pressure sensor 26 and a fifth temperature sensor 27; the exhaust gas cooling unit includes a heat exchanger 28; the pressure control unit includes a back pressure valve 29; the gas-liquid separation unit includes an exhaust port 30; the output end of the heater 22 is sequentially connected to the sixth pressure sensor 23, the fourth temperature sensor 24, the dew point sensor 25 to one end of the fuel cell stack, and the other end of the fuel cell stack is sequentially connected to the seventh pressure sensor 26, the fifth temperature sensor 27, the heat exchanger 28, the back pressure valve 29, and the exhaust port 30.

[0073] The sixth pressure sensor 23, the fourth temperature sensor 24, and the dew point sensor 25 are located in front of the electric stack inlet and are used to detect the pressure, temperature, and dew point temperature of the gas before entering the electric stack.

[0074] The seventh pressure sensor 26 and the fifth temperature sensor 27 are located at the gas outlet of the stack and are used to monitor the pressure and temperature.

[0075] The gas exiting the stack is cooled by the heat exchanger 28.

[0076] The back pressure valve 29 is located at the rear end of the heat exchanger 28 and is used for the pressure control of the entire test system.

[0077] The cooled tail gas is discharged after gas-liquid separation through the tail gas outlet 30.

[0078] Embodiment Four

[0079] As Figure 6 shown, it is the connection structure diagram of a fuel cell system of a system for adjusting the gas dew point temperature according to Embodiment Four of the present invention. Embodiment Four corresponds to the specific application of Embodiment Two and is similar to Embodiment Three, so no more details will be elaborated here.

[0080] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for regulating gas dew point temperature, characterized in that: It includes a gas filtering unit, a flow control unit, a switching unit, a humidifying unit, a mixing unit, and a temperature control unit; the gas filtering unit, the flow control unit, the switching unit, the mixing unit, and the temperature control unit are connected in sequence, wherein the connection between the switching unit and the mixing unit is divided into two paths, one of which is that the switching unit is directly connected to the mixing unit, and the other also includes a humidifying unit, the switching unit is first connected to the humidifying unit, and the humidifying unit is then connected to the mixing unit; The gas filtration unit filters the input gas, the flow control unit controls the input gas flow, and the switching unit adjusts the output gas to dry gas, wet gas, or a mixture of dry and wet gas according to the gas volume demand; the gas enters the temperature control unit, which heats the gas and outputs gas with a dew point temperature and temperature that meets the engineering requirements; The switching unit comprises a first three-way valve (7) and a second three-way valve (8); The input end of the first three-way valve (7) is connected to a second flow meter (36) or a second flow controller (4) on the dry-wet switching branch, and the input end of the second three-way valve (8) is connected to a third flow meter (37) or a third flow controller (5) on another dry-wet switching branch; One of the output ends of the first three-way valve (7) and one of the output ends of the second three-way valve (8) are connected to the first flow meter (35) or the first flow controller (3) on the dry gas branch line and connected to the mixing unit; Another output end of the first three-way valve (7) and another output end of the second three-way valve (8) are connected to a fourth flow meter (38) or a fourth flow controller (6) on the wet gas branch line and connected to the humidification unit; The humidification unit comprises a humidifier and a second temperature sensor (17), wherein the output end of the humidifier is connected to one end of the second temperature sensor (17) for detecting outlet gas; The dry gas branch, the wet gas branch, and the dry-wet switching branch are connected in parallel, and the flow rates of dry gas and wet gas are quickly distributed by utilizing the first three-way valve (7) and the second three-way valve (8).

2. A system for adjusting gas dew point temperature according to claim 1, characterized in that: The flow control unit comprises a first proportional valve (31), a second proportional valve (32), a third proportional valve (33), a fourth proportional valve (34), a first flow meter (35), a second flow meter (36), a third flow meter (37), and a fourth flow meter (38); one end of the first proportional valve (31), one end of the second proportional valve (32), one end of the third proportional valve (33), and one end of the fourth proportional valve (34) are connected to the gas filter unit, the other end of the first proportional valve (31) is connected to one end of the first flow meter (35), the other end of the second proportional valve (32) is connected to one end of the second flow meter (36), the other end of the third proportional valve (33) is connected to one end of the third flow meter (37), the other end of the fourth proportional valve (34) is connected to one end of the fourth flow meter (38), and the other end of the first flow meter (35), the other end of the second flow meter (36), the other end of the third flow meter (37), and the other end of the fourth flow meter (38) are connected to the switching unit.

3. The system for adjusting the gas dew point temperature according to claim 1, characterized in that: The flow control unit comprises a first flow controller (3), a second flow controller (4), a third flow controller (5), and a fourth flow controller (6); one end of the first flow controller (3), one end of the second flow controller (4), one end of the third flow controller (5), and one end of the fourth flow controller (6) are connected to the gas filtering unit, and the other end of the first flow controller (3), the other end of the second flow controller (4), the other end of the third flow controller (5), and the other end of the fourth flow controller (6) are connected to the switching unit.

4. The system for adjusting the dew point temperature of gas according to claim 1, characterized in that: The humidifying unit comprises a second check valve (10), a second pressure sensor (11), a water replenishment valve (12), a third check valve (13), a drain valve (14), and a fourth pressure sensor (18); one end of the second check valve (10) is connected to the wet gas branch of the switching unit, the other end of the second check valve (10) is connected to one end of the second pressure sensor (11), the other end of the second pressure sensor (11) is connected to the input end of the humidifier, the humidifier further comprises a water replenishment end and a drain end, the water replenishment valve (12) is connected to one end of the third check valve (13), the other end of the third check valve (13) is connected to the water replenishment end of the humidifier, the drain end of the humidifier is connected to the drain valve (14), the other end of the second temperature sensor (17) is connected to one end of the fourth pressure sensor (18), and the other end of the fourth pressure sensor (18) is connected to the mixing unit.

5. The system for adjusting the gas dew point temperature according to claim 4, characterized in that: The humidifying unit further comprises a third pressure sensor (15) and a first temperature sensor (16); the third pressure sensor (15) and the first temperature sensor (16) are mounted on a side wall of the humidifier.

6. A method for temperature regulation using the system for regulating gas dew point temperature according to any one of claims 1 to 5, characterized in that: The following steps are included: Step 1, inputting gas, and the gas filtering unit filters the input gas; Step 2: The gas enters the flow control unit, and the flow rate of the input gas is controlled by setting the flow unit; Step 3, the gas enters the switching unit, and the switching unit adjusts the output gas to dry gas, wet gas, or a mixture of dry and wet gas according to the gas volume demand. The switching unit flexibly adjusts the output gas according to the dry gas or wet gas volume demand; Step 4: The gas enters the temperature control unit, which heats the gas and outputs gas with a dew point temperature and temperature that meets engineering requirements.

7. The method according to claim 6, characterized in that The step 3 also includes: Step 31, when there is a difference between the dew point temperature values ​​of the dry gas and the wet gas required for the system test, the dry gas and the wet gas are ventilated at the same time to work, at this time, the switching unit is directly connected to the mixing unit, and the switching unit is connected to the mixing unit through the humidifying unit, and the switching unit flexibly adjusts the output according to the demand for dry gas or wet gas; Step 32: When the gas required for the system test does not need to be humidified, the wet gas input is stopped and only the dry gas is output, that is, the switching unit is directly connected to the mixing unit, and the switching unit is not connected to the humidifying unit; Step 33, when the dew point temperature of the wet gas meets the dew point temperature of the gas required for the required system test, stop the dry gas input and only input the wet gas, that is, the switching unit is not connected to the mixing unit, and the switching unit is connected to the mixing unit through the humidifying unit.

8. A fuel cell system using the system for adjusting the gas dew point temperature according to any one of claims 1 to 5, characterized in that: It also includes a fuel cell stack, a tail exhaust cooling unit, a pressure control unit, and a gas-liquid separation unit which are sequentially connected after the temperature control unit; It also includes a detection unit before and after the battery stack, one end of which is located between the temperature control unit and the battery stack connection line, and the other end of which is located between the battery stack and the tail exhaust cooling unit connection line; The detection unit before and after the battery stack comprises a sixth pressure sensor (23), a fourth temperature sensor (24), a dew point sensor (25), a seventh pressure sensor (26), and a fifth temperature sensor (27); one end of the sixth pressure sensor (23) is connected to the temperature control unit, the other end of the sixth pressure sensor (23) is connected to one end of the fourth temperature sensor (24), the other end of the fourth temperature sensor (24) is connected to one end of the dew point sensor (25), the other end of the dew point sensor (25) is connected to one end of the battery stack, the other end of the battery stack is connected to one end of the seventh pressure sensor (26), the other end of the seventh pressure sensor (26) is connected to one end of the fifth temperature sensor (27), and the other end of the fifth temperature sensor (27) is connected to the tail exhaust cooling unit.

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