Control method of hydrogen reflux control system for fuel cell test platform

Abstract

The present invention belongs to the field of fuel cell technology and discloses a hydrogen reflux control system and control method for a fuel cell test platform. The system comprises a fuel cell stack, a plate heat exchanger, a condensate water separation tank, and a hydrogen reflux pump, which are sequentially connected in a closed loop. The circulation pipeline is equipped with a T-type thermocouple temperature sensor, an oil mist filter, a reflux pump outlet shutoff valve, a hydrogen inlet branch, a pressure regulating valve, a hydrogen outlet branch, a reflux pump inlet shutoff valve, a proportional regulating valve, and a drain pipeline. The plate heat exchanger is also connected to a secondary water inlet and outlet pipeline, and the drain pipeline is equipped with a drain valve. The connecting pipeline between the condensate water separation tank and the hydrogen reflux pump is equipped with a hydrogen tail exhaust branch and a heating cable for the reflux pump inlet pipeline. A manual exhaust valve is also provided on the hydrogen tail exhaust branch. The system significantly reduces hydrogen usage and avoids hydrogen waste.

Description

Technical Field

[0001] The present invention belongs to the technical field of fuel cells, and in particular relates to a control method for a hydrogen reflux control system of a fuel cell test platform. Background Art

[0002] The hydrogen reflux system is usually used in the control system after installation. Even if it is installed on the vehicle, it is only used to simply control the reflux flow. It is rarely used on the test platform to accurately control its reflux flow, reflux temperature and reflux pressure. However, with the continuous development of the fuel cell industry, more and more users are considering the cost and actual usage of hydrogen. There is an urgent need for the test platform to be equipped with a hydrogen reflux system that can accurately control the reflux flow, reflux temperature and reflux pressure of hydrogen. On the one hand, it can avoid the waste of hydrogen fuel during the test, and on the other hand, it can achieve test conditions that simulate actual operating conditions as much as possible.

[0003] Fuel cell testing is usually conducted in a normal discharge mode with a certain excess coefficient. This will result in a large portion of the gas not fully participating in the reaction and being discharged directly into the atmosphere, resulting in unnecessary waste. It also fails to simulate actual usage, so the test platform needs to have a hydrogen reflow system. The temperature of the reflux gas will be very high after passing through the fuel cell reactor. If the reflux pump is used alone to directly return the gas to the inlet of the stack, the temperature and pressure of the reflux gas will be slightly higher than the normal gas entering the stack. This makes it difficult to accurately control the temperature and pressure of the actual gas entering the stack. This requires a hydrogen reflux temperature control system and a pressure control system to accurately control the reflux temperature and pressure. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology in terms of gas waste and inability to simulate actual usage, the present invention provides a control method for the hydrogen reflux control system of a fuel cell test platform. The method adopts PID control, cools and separates the reflux gas through a secondary cooling system, and then cooperates with a high-precision pressure-stabilizing valve to control the stack pressure, thereby achieving precise control of the temperature and pressure of the hydrogen reflux gas.

[0005] The above-mentioned object of the present invention is achieved through the following technical solutions: a control method for a hydrogen reflux control system of a fuel cell test platform, the control system including a pressure regulating valve, a reflux pump outlet stop valve, a reflux pump outlet pipeline heating tape, an oil mist filter, a hydrogen reflux pump, a reflux pump inlet stop valve, a plate heat exchanger, a proportional regulating valve, a manual exhaust valve, a condensate water distribution tank, a drain valve, a reflux pump inlet pipeline heating tape, a hydrogen inlet branch, a fuel cell stack, a hydrogen outlet branch, and a T-type thermocouple temperature sensor. The fuel cell stack, plate heat exchanger, condensate water distribution tank, and hydrogen reflux pump are connected in sequence to form a closed loop; the connecting pipeline between the hydrogen reflux pump and the fuel cell stack is provided with a T-type thermocouple temperature sensor, a reflux pump outlet pipeline heating tape b, an oil mist filter, a reflux pump outlet pipeline heating tape a, a reflux pump outlet stop valve, and a hydrogen inlet branch, and a pressure regulating valve is provided on the hydrogen inlet branch; the connecting pipeline between the fuel cell stack and the plate heat exchanger is provided with a hydrogen outlet branch and a reflux pump inlet stop valve, and the plate heat exchanger is also connected to a secondary water inlet pipeline and a secondary water outlet pipeline, and a proportional regulating valve is provided on the secondary water outlet pipeline; a drain pipeline is provided on the condensate water distribution tank, and a drain valve is provided on the drain pipeline; a hydrogen tail exhaust branch and a reflux pump inlet pipeline heating tape are provided on the connecting pipeline between the condensate water distribution tank and the hydrogen reflux pump, and a manual exhaust valve is provided on the hydrogen tail exhaust branch.

[0006] The control method of the hydrogen reflux control system of the fuel cell test platform is as follows: when the hydrogen reflux control system of the fuel cell test platform is working, the reflux pump inlet stop valve and the reflux pump outlet stop valve are opened, the pressure regulating valve is opened, and hydrogen enters the fuel cell stack from the hydrogen inlet branch. The hydrogen at the outlet of the fuel cell stack enters the plate heat exchanger through the pipeline for temperature control: the outlet temperature of the hydrogen reflux pump is used as feedback to control the proportional control valve on the secondary water outlet pipeline using the PID closed-loop control method to adjust the flow of secondary cooling water, so as to control the temperature of the reflux hydrogen at a reasonable value, thereby achieving precision. Temperature control; the gas-water mixture discharged after treatment by the plate heat exchanger is separated into gas and water using a condensation water separator. The separated gas enters the hydrogen reflux pump through a heating and insulation pipeline. The reflux amount of hydrogen is controlled by controlling the speed of the hydrogen reflux pump. The gas pumped out by the hydrogen reflux pump is measured by a T-type thermocouple temperature sensor, the temperature is controlled by heating and insulation pipelines and re-enters the fuel cell stack. The pressure entering the fuel cell stack is used as feedback, and the PID closed-loop control method is used to control the action of the pressure regulating valve and the pressure of the hydrogen entering the fuel cell stack.

[0007] The beneficial effects of the present invention compared with the prior art are:

[0008] 1. Compared with normal exhaust control, hydrogen reflux control greatly saves hydrogen consumption and avoids hydrogen waste.

[0009] 2. Compared with the hydrogen reflux control in conventional systems, the hydrogen reflux control of the fuel cell test platform can more accurately control the reflux volume, reflux pressure and reflux temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a structural diagram of the hydrogen reflux control system of the fuel cell test platform of the present invention.

[0011] In the figure, 1. pressure-stabilizing valve; 2. reflux pump outlet stop valve; 3. reflux pump outlet pipeline heating tape a; 4. oil mist filter; 5. reflux pump outlet pipeline heating tape b; 6. reflux pump inlet stop valve; 7. plate heat exchanger; 8. proportional control valve; 9. manual exhaust valve; 10. condensate water separation tank; 11. drain valve; 12. reflux pump inlet pipeline heating tape; 13. T-type thermocouple temperature sensor; 14. fuel cell stack; 15. hydrogen reflux pump; 16. hydrogen inlet branch; 17. hydrogen outlet branch; 18. secondary water inlet pipeline; 19. secondary water outlet pipeline; 20. hydrogen tail exhaust branch; 21. drain pipeline. DETAILED DESCRIPTION

[0012] The present invention is described in detail below by specific examples, but the scope of protection of the present invention is not limited. Unless otherwise specified, the experimental methods adopted in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0013] Example 1

[0014] A hydrogen reflux control system for a fuel cell test platform includes a pressure-stabilizing valve 1, a reflux pump outlet stop valve 2, a heating tape for the reflux pump outlet pipeline, an oil mist filter 4, a hydrogen reflux pump 15, a reflux pump inlet stop valve 6, a plate heat exchanger 7, a proportional regulating valve 8, a manual exhaust valve 9, a condensate water separation tank 10, a drain valve 11, a heating tape for the reflux pump inlet pipeline 12, a hydrogen inlet branch 16, a fuel cell stack 14, and a hydrogen outlet branch 17. The fuel cell stack 14, the plate heat exchanger 7, the condensate water separation tank 10, and the hydrogen reflux pump 15 are sequentially connected to form a closed loop; the connection pipeline between the hydrogen reflux pump 15 and the fuel cell stack 14 is provided with a T-type thermocouple temperature sensor 13, a reflux pump outlet pipeline heating tape b5, an oil mist filter 4, a reflux pump outlet pipeline heating tape a3, a reflux pump outlet stop valve 2 and a hydrogen inlet branch 16, and a pressure regulating valve 1 is provided on the hydrogen inlet branch 16; the connection pipeline between the fuel cell stack 14 and the plate heat exchanger 7 is provided with a pressure regulating valve 1. A hydrogen out-of-stack branch 17 and a reflux pump inlet stop valve 6 are provided in sequence. A secondary water inlet pipeline 18 and a secondary water outlet pipeline 19 are also connected to the plate heat exchanger 7, and a proportional regulating valve 8 is provided on the secondary water outlet pipeline 19; a drainage pipeline 21 is provided on the condensate water separation tank 10, and a drainage valve 11 is provided on the drainage pipeline 21; a hydrogen tail exhaust branch 20 and a reflux pump inlet pipeline heating tape 12 are provided on the connecting pipeline between the condensate water separation tank 10 and the hydrogen reflux pump 15, and a manual exhaust valve 9 is provided on the hydrogen tail exhaust branch 20.

[0015] When the hydrogen reflux control system of the fuel cell test platform is working, the reflux pump inlet stop valve 6 and the reflux pump outlet stop valve 2 are opened, the pressure regulating valve 1 is opened, and hydrogen enters the fuel cell stack 14 from the hydrogen inlet branch 16. The hydrogen at the outlet of the fuel cell stack 14 enters the plate heat exchanger 7 through the pipeline for temperature control: the outlet temperature of the hydrogen reflux pump 15 is used as feedback to control the proportional control valve 8 on the secondary water outlet pipeline 19 using the PID closed-loop control method to adjust the flow of secondary cooling water, and the temperature of the reflux hydrogen is controlled at a reasonable value to achieve the purpose of precise temperature control; the gas-water mixture discharged after treatment by the plate heat exchanger 7 is separated into gas and water by using the condensation water separation tank 10, and the separated gas enters the hydrogen reflux pump 15 through the heating and insulation pipeline, and the reflux amount of hydrogen is controlled by controlling the speed of the hydrogen reflux pump 15.

[0016] The gas pumped out by the hydrogen reflux pump 15 is temperature-measured by a T-type thermocouple temperature sensor 13, and re-enters the fuel cell stack 14 through a heating and insulation pipeline. The pressure entering the fuel cell stack 14 is used as feedback, and a PID closed-loop control method is used to control the action of the pressure regulating valve 1 and the pressure of the hydrogen entering the fuel cell stack 14, thereby achieving the purpose of accurately controlling the reflux intake pressure.

[0017] Example 2

[0018] The same fuel cell test platform hydrogen reflux control system as in Example 1

[0019] The speed of the hydrogen reflux pump 15 is 3000 rpm, the hydrogen reflux temperature into the stack is 59° C., and the hydrogen reflux pressure into the stack is 1 bar.

[0020] Open reflux pump outlet shutoff valve 2 and reflux pump inlet shutoff valve 6 to clear the hydrogen reflux pipeline. Then, introduce hydrogen and set the feed pressure to 1 bar. The system automatically adjusts the action of pressure-stabilizing valve 1 based on the actual feed pressure feedback, accurately controlling the feed pressure to 1 bar. Then, start hydrogen reflux pump 15 and set its speed to 3000 rpm. At this point, the feed pressure will deviate from the set value, and pressure-stabilizing valve 1 will automatically adjust itself based on the actual feed pressure feedback, accurately controlling the feed pressure to 1 bar.

[0021] Then set the intake temperature to 59°C. At this time, hydrogen at 59°C enters the fuel cell stack 14 to react, and unreacted hydrogen will flow out through the outlet of the fuel cell stack 14. At this time, the gas is heated for the second time by the fuel cell stack 14, and the temperature will be higher than the 59°C temperature when entering the stack. The high-temperature hydrogen passes through the reflux pump inlet stop valve 6 and enters the plate heat exchanger 7 for cooling. The temperature feedback at the outlet of the hydrogen reflux pump 15 is used to adjust the proportional control valve 8 of the secondary cooling water of the plate heat exchanger 7, adjust the cold water flow, and control the hydrogen temperature at the outlet of the hydrogen reflux pump 15 to the intake temperature of 59°C, so that the temperature entering the stack is accurately controlled at 59°C.

[0022] The gas cooled by the plate heat exchanger flows into the condensation water separation tank 10 through a pipeline for gas-water separation. The separated gas comes out from the top of the tank and passes through a heating and insulation pipeline wrapped with a heating tape to enter the hydrogen reflux pump 15. The 59°C gas coming out of the hydrogen reflux pump 15 passes through an oil mist filter 4 to remove any oil mist that may be carried, and then flows to the heating and insulation pipeline wrapped with a heating tape to re-enter the reactor for reaction.

[0023] When the water level in the condensate water separation tank 10 reaches a certain level, the condensate water separation tank drain valve 11 is automatically opened to drain some of the excess condensate. When the operation stops, the manual exhaust valve 9 above the condensate water separation tank 10 is opened to release the gas in the pipe to avoid a large amount of gas residue.

[0024] The above-described embodiments are only preferred embodiments of the present invention, and are not intended to be all feasible embodiments of the present invention. Any obvious modifications made by a person skilled in the art without departing from the principles and spirit of the present invention should be considered to be included within the scope of protection of the claims of the present invention.

Claims

1. A control method for a hydrogen reflux control system of a fuel cell test platform, characterized in that: The fuel cell test platform hydrogen reflux control system comprises a pressure regulating valve (1), a reflux pump outlet stop valve (2), a reflux pump outlet pipeline heating tape, an oil mist filter (4), a hydrogen reflux pump (15), a reflux pump inlet stop valve (6), a plate heat exchanger (7), a proportional regulating valve (8), a manual exhaust valve (9), a condensation water separation tank (10), a drain valve (11), a reflux pump inlet pipeline heating tape (12), a hydrogen inlet branch (16), a fuel cell stack (14), and a hydrogen outlet branch (17); the fuel cell stack (14), the plate heat exchanger (7), the condensation water separation tank (10), and the hydrogen reflux pump (15) are sequentially connected to form a closed loop; a T-type thermocouple temperature sensor (13), a reflux pump outlet pipeline heating tape b (5), an oil mist filter (4) are sequentially provided on the connecting pipeline between the hydrogen reflux pump (15) and the fuel cell stack (14); ), a heat tracing belt a (3) for the outlet pipeline of the reflux pump, a stop valve (2) for the outlet of the reflux pump, and a hydrogen inlet branch (16), a pressure regulating valve (1) is provided on the hydrogen inlet branch (16); a hydrogen outlet branch (17) and a stop valve (6) for the inlet of the reflux pump are provided on the connecting pipeline of the fuel cell stack (14) and the plate heat exchanger (7), and a secondary water inlet pipeline (18) and a secondary water outlet pipeline are also connected to the plate heat exchanger (7) (19), a proportional regulating valve (8) is provided on the secondary water outlet pipe (19); a drainage pipe (21) is provided on the condensate water separation tank (10), and a drainage valve (11) is provided on the drainage pipe (21); a hydrogen tail discharge branch (20) and a reflux pump inlet pipe heating tape (12) are provided on the connecting pipe between the condensate water separation tank (10) and the hydrogen reflux pump (15), and a manual exhaust valve (9) is provided on the hydrogen tail discharge branch (20); The control method is as follows: when the hydrogen reflux control system of the fuel cell test platform is working, the reflux pump inlet stop valve (6) and the reflux pump outlet stop valve (2) are opened, and the pressure regulating valve (1) is opened, and hydrogen enters the fuel cell stack (14) from the hydrogen inlet branch (16), and the hydrogen at the outlet of the fuel cell stack (14) enters the plate heat exchanger (7) through the pipeline for temperature control: the outlet temperature of the hydrogen reflux pump (15) is used as feedback to control the proportional regulating valve (8) on the secondary water outlet pipeline (19) by using the PID closed-loop control method to adjust the flow of the secondary cooling water, so that the temperature of the reflux hydrogen is controlled at a reasonable value, thereby achieving precise temperature control; after the plate heat exchanger The gas-water mixture discharged after treatment by the device (7) is separated into gas and water by using a condensation water separation tank (10); the separated gas enters a hydrogen reflux pump (15) through a heating and heat preservation pipeline; the reflux amount of hydrogen is controlled by controlling the rotation speed of the hydrogen reflux pump (15); the gas pumped out by the hydrogen reflux pump (15) is temperature-measured by a T-type thermocouple temperature sensor (13); the temperature is controlled by using a heating and heat preservation pipeline and the gas re-enters the fuel cell stack (14); the pressure entering the fuel cell stack (14) is used as feedback, and a PID closed-loop control method is used to control the action of the pressure regulating valve (1) and the pressure of the hydrogen entering the fuel cell stack (14) is controlled.

2. The control method of the hydrogen reflux control system of the fuel cell test platform according to claim 1, characterized in that: The speed of the hydrogen reflux pump (15) is 3000 rpm, the hydrogen inlet temperature is 59°C, and the hydrogen inlet pressure is 1 bar.

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