Liquid hydrogen flow low-temperature measurement system under renewable energy source hydrogen production condition

Abstract

The invention relates to the technical field of electronics, and discloses a liquid hydrogen flow low-temperature measurement system under a renewable energy source hydrogen production condition, the system comprises a liquid hydrogen supply device, a liquid hydrogen Dewar, a liquid hydrogen flow measurement module, a liquid nitrogen container and a control module, the system is provided with the liquid hydrogen Dewar between the liquid hydrogen supply device and the liquid hydrogen flow measurement module; the control module is used for controlling the liquid hydrogen Dewar to pressurize liquid hydrogen, the stability of the pressure of the liquid hydrogen flowing into the liquid hydrogen flow measuring module is guaranteed, the liquid nitrogen container is arranged at the output end of the liquid hydrogen flow measuring module, and the control module is used for controlling the heater to heat liquid nitrogen in the liquid nitrogen container. The pressure of the liquid hydrogen at the output end of the liquid hydrogen flow measuring module is within the preset range, the stability of the temperature of the liquid hydrogen flowing out of the liquid hydrogen flow measuring module is guaranteed, the stability of the pressure of the liquid hydrogen at the output end is further guaranteed, and the low-temperature liquid hydrogen flow measured by the liquid hydrogen flow measuring device is more accurate.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to a low-temperature measurement system for liquid hydrogen flow under conditions of hydrogen production from renewable energy. Background Art

[0002] During the hydrogen production process, hydrogen is liquefied through a liquid hydrogen supply device to obtain liquid hydrogen, which is convenient for subsequent transportation and storage. In the production, transportation, storage and other links of liquid hydrogen, it is necessary to measure the flow rate of liquid hydrogen to ensure the stability of liquid hydrogen production and the safety of transportation and storage. In the related art, a liquid hydrogen flow measuring device is generally used to measure the flow rate of liquid hydrogen. The liquid hydrogen flow measuring device is a device for measuring the flow rate of liquid hydrogen. The liquid hydrogen flow measuring device calculates the flow rate data of liquid hydrogen by combining the pressure difference between the liquid hydrogen pressure flowing into the device and the liquid hydrogen pressure flowing out of the device with the physical parameters such as the density of liquid hydrogen. Therefore, the accuracy of the measurement of the liquid hydrogen pressure flowing into the device and the liquid hydrogen pressure flowing out of the device will affect the accuracy of the final flow data. When measuring the flow rate of low-temperature liquid hydrogen in the related art, it is generally carried out under normal temperature conditions. Liquid hydrogen will vaporize under normal temperature conditions, which will cause the pressure of liquid hydrogen to change, resulting in errors in the measurement of the liquid hydrogen pressure flowing into and out of the device, resulting in the final liquid hydrogen flow measurement result being inaccurate. Summary of the Invention

[0003] In view of this, the present invention provides a low-temperature measurement system for liquid hydrogen flow under renewable energy hydrogen production conditions to solve the problem that the related art uses a liquid hydrogen flow measurement device to measure the low-temperature liquid hydrogen flow under normal temperature conditions, resulting in inaccurate measurement results.

[0004] In a first aspect, the present invention provides a low-temperature measurement system for liquid hydrogen flow under renewable energy hydrogen production conditions, the system comprising: a liquid hydrogen supply device, a liquid hydrogen dewar, a liquid hydrogen flow measurement module, a liquid nitrogen container, and a control module; the output end of the liquid hydrogen supply device is connected to the input end of the liquid hydrogen dewar, and the liquid hydrogen supply device is used to produce liquid hydrogen; the output end of the liquid hydrogen dewar is connected to the input end of the liquid hydrogen flow measurement module; a nitrogen heating coil and a heater are provided in the liquid nitrogen container, and the output end of the liquid hydrogen flow measurement module is connected to the input end of the nitrogen heating coil; the control module is respectively connected to the liquid hydrogen dewar, the liquid hydrogen flow measurement module, and the heater, and is used to control the liquid hydrogen dewar to pressurize the liquid hydrogen when receiving a liquid hydrogen flow measurement instruction, so that the liquid hydrogen pressure in the liquid hydrogen dewar meets a preset condition, control the liquid hydrogen flow measurement module to measure the liquid hydrogen flow, and control the heater to heat the liquid nitrogen in the liquid nitrogen container, so that the pressure of the liquid hydrogen at the output end of the liquid hydrogen flow measurement module is within a preset range.

[0005] The present invention provides a low-temperature measurement system for liquid hydrogen flow under renewable energy hydrogen production conditions, comprising a liquid hydrogen supply device, a liquid hydrogen dewar, a liquid hydrogen flow measurement module, a liquid nitrogen container, and a control module. The output end of the liquid hydrogen supply device is connected to the input end of the liquid hydrogen dewar, and the liquid hydrogen supply device is used to produce liquid hydrogen. The output end of the liquid hydrogen dewar is connected to the input end of the liquid hydrogen flow measurement module. The liquid nitrogen container is provided with a nitrogen heating coil and a heater, and the output end of the liquid hydrogen flow measurement module is connected to the input end of the nitrogen heating coil. The control module is respectively connected to the liquid hydrogen dewar, the liquid hydrogen flow measurement module, and the heater, and is used to control the liquid hydrogen dewar to pressurize the liquid hydrogen upon receiving a liquid hydrogen flow measurement instruction so that the liquid hydrogen pressure in the liquid hydrogen dewar meets a preset condition, control the liquid hydrogen flow measurement module to measure the liquid hydrogen flow, and control the heater to heat the liquid nitrogen in the liquid nitrogen container so that the pressure of the liquid hydrogen at the output end of the liquid hydrogen flow measurement module is within a preset range. The system provided by the present invention ensures the stability of the pressure of the liquid hydrogen flowing into the liquid hydrogen flow measurement module by arranging a liquid hydrogen dewar between the liquid hydrogen supply device and the liquid hydrogen flow measurement module, and controlling the liquid hydrogen dewar to pressurize the liquid hydrogen by using a control module. Furthermore, by arranging a liquid nitrogen container at the output end of the liquid hydrogen flow measurement module and controlling a heater to heat the liquid nitrogen in the liquid nitrogen container by using the control module, the pressure of the liquid hydrogen at the output end of the liquid hydrogen flow measurement module is kept within a preset range, thereby ensuring the stability of the temperature of the liquid hydrogen flowing out of the liquid hydrogen flow measurement module, reducing the possibility of vaporization of the liquid hydrogen flowing out of the output end of the liquid hydrogen flow measurement module, and ensuring the stability of the liquid hydrogen pressure at the output end. Under the premise that the liquid hydrogen pressures at the input and output of the liquid hydrogen flow measurement module are stable, the accuracy of the low-temperature measurement results of the liquid hydrogen flow measurement device can be guaranteed.

[0006] In an optional embodiment, the system further comprises a vaporizer, and the output end of the nitrogen heating coil is connected to the input end of the vaporizer.

[0007] In an optional embodiment, the system further includes a reflux valve and an exhaust pipeline; the output end of the vaporizer is connected to the input end of the exhaust pipeline through the reflux valve, and the output end of the exhaust pipeline is connected to the input end of the liquid hydrogen supply device.

[0008] In an optional embodiment, the system also includes a first pipeline, which includes a first control valve and a standard flow meter; the output end of the vaporizer is connected to the input end of the standard flow meter through the first control valve, and the output end of the standard flow meter is connected to the input end of the liquid hydrogen supply device.

[0009] In an optional embodiment, the system further includes a second pipeline, which includes a second control valve and a hydrogen storage tank; the output end of the vaporizer is connected to the hydrogen storage tank through the second control valve.

[0010] In an optional embodiment, the system further includes a bypass line, the bypass line is connected in parallel with the liquid hydrogen flow measurement module, the bypass line includes a bypass valve, and the liquid hydrogen flow measurement module includes a measurement control valve.

[0011] In an optional embodiment, the control module is further configured to control the measurement control valve to close and the bypass valve to open when receiving a test instruction for liquid hydrogen flow measurement.

[0012] In an optional embodiment, the liquid hydrogen dewar includes a self-pressurizing valve and a safety valve; the control module controls the self-pressurizing valve to open so that the liquid hydrogen dewar pressurizes the liquid hydrogen.

[0013] In an optional embodiment, a nitrogen replenishing valve is further provided in the liquid nitrogen container. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0015] Figure 1 is a structural block diagram of a system for measuring the low-temperature flow rate of liquid hydrogen under conditions of hydrogen production from renewable energy according to an embodiment of the present invention;

[0016] Figure 2 This is a structural block diagram of a system for measuring the low-temperature flow rate of liquid hydrogen under another renewable energy hydrogen production condition according to an embodiment of the present invention; DETAILED DESCRIPTION

[0017] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0018] In the related art, a liquid hydrogen flow measuring device is generally used to measure the liquid hydrogen flow. The liquid hydrogen flow measuring device is a device for measuring the liquid hydrogen flow. The liquid hydrogen flow measuring device calculates the liquid hydrogen flow data by combining the pressure difference between the liquid hydrogen pressure flowing into the device and the liquid hydrogen pressure flowing out of the device with the liquid hydrogen physical properties. Therefore, the accuracy of the measurement of the liquid hydrogen pressure flowing into the device and the liquid hydrogen pressure flowing out of the device will affect the accuracy of the final flow data. When measuring the low-temperature liquid hydrogen flow in the related art, it is generally carried out under normal temperature conditions. Liquid hydrogen will vaporize under normal temperature conditions, which will cause the pressure of liquid hydrogen to change, resulting in errors in the measurement of the liquid hydrogen pressure flowing into and out of the device, resulting in inaccurate measurement results of the final low-temperature liquid hydrogen flow.

[0019] In view of this, an embodiment of the present application provides a low-temperature measurement system for liquid hydrogen flow under renewable energy hydrogen production conditions to achieve liquid hydrogen flow measurement. The system provided by the present invention, by setting a liquid hydrogen dewar between the liquid hydrogen supply device and the liquid hydrogen flow measurement module, using a control module to control the liquid hydrogen dewar to pressurize the liquid hydrogen, thereby ensuring the stability of the liquid hydrogen pressure flowing into the liquid hydrogen flow measurement module, and by setting a liquid nitrogen container at the output end of the liquid hydrogen flow measurement module, using the control module to control the heater to heat the liquid nitrogen in the liquid nitrogen container, so that the pressure of the liquid hydrogen at the output end of the liquid hydrogen flow measurement module is within a preset range, thereby ensuring the stability of the liquid hydrogen temperature flowing out of the liquid hydrogen flow measurement module, reducing the possibility of vaporization of the liquid hydrogen flowing out of the output end of the liquid hydrogen flow measurement module, and ensuring the stability of the liquid hydrogen pressure at the output end. Under the premise that the liquid hydrogen pressure at the input and output of the liquid hydrogen flow measurement module is stable, the accuracy of the low-temperature liquid hydrogen flow measured by the liquid hydrogen flow measurement device can be guaranteed.

[0020] In this embodiment, a low-temperature measurement system for liquid hydrogen flow under renewable energy hydrogen production conditions is provided. Figure 1 FIG. 1 is a block diagram of a system for measuring the low temperature flow rate of liquid hydrogen under conditions of hydrogen production from renewable energy according to an embodiment of the present invention. Figure 1 As shown, the system includes: a liquid hydrogen supply device 1, a liquid hydrogen dewar 2, a liquid hydrogen flow measurement module 3, a liquid nitrogen container 4 and a control module;

[0021] The output end of the liquid hydrogen supply device 1 is connected to the input end of the liquid hydrogen dewar 2. The liquid hydrogen supply device 1 is used to produce liquid hydrogen. For example, the liquid hydrogen supply device 1 is used to produce liquid hydrogen, and the produced liquid hydrogen will flow into the liquid hydrogen dewar 2 through a pipeline.

[0022] The output end of the liquid hydrogen dewar 2 is connected to the input end of the liquid hydrogen flow measurement module 3. For example, when performing cryogenic measurement of liquid hydrogen flow, the liquid hydrogen dewar pressurizes the liquid hydrogen. Since the volume inside the liquid hydrogen dewar 2 is fixed, the liquid hydrogen flows in and then flows out under the pressure inside the dewar, flowing through the pipeline into the liquid hydrogen flow measurement device in the liquid hydrogen flow measurement module 3.

[0023] A nitrogen heating coil 5 and a heater 6 are provided in the liquid nitrogen container 4, and the output end of the liquid hydrogen flow measurement module 3 is connected to the input end of the nitrogen heating coil 5. Exemplarily, liquid nitrogen is stored in the liquid nitrogen container 4, and the nitrogen heating coil 5 part is immersed in a liquid nitrogen solution, and the liquid nitrogen solution can provide a low temperature environment for the liquid hydrogen flowing out of the liquid hydrogen flow measurement module 3. The heater 6 can regulate the ratio of liquid nitrogen and nitrogen in the liquid nitrogen container 4, for the stability of the internal pressure of the liquid nitrogen container 4 and the contact area of the nitrogen heating coil 5 with low temperature nitrogen and liquid nitrogen, the nitrogen heating coil 5 is inside the liquid nitrogen container, and it contacts low temperature nitrogen and liquid nitrogen respectively, by temperature stratification and curved pipeline arrangement, it can effectively isolate the outside from heat leakage, achieve gas sealing effect, avoid under the conditions of renewable energy hydrogen production, when liquid hydrogen flow is small or there is no time, the outside normal temperature hydrogen flows into the liquid hydrogen flow measurement and analysis device, causing a large amount of heat leakage. The liquid hydrogen dewar 2 can provide a larger volume for liquid hydrogen storage, reduces the pressure fluctuation change at the front end of the liquid hydrogen flow measurement device.

[0024] The control module is respectively connected to the liquid hydrogen dewar 2, the liquid hydrogen flow measurement module 3, and the heater 6. When receiving the liquid hydrogen flow measurement instruction, the control module controls the liquid hydrogen dewar 2 to pressurize the liquid hydrogen so that the liquid hydrogen pressure in the liquid hydrogen dewar 2 meets the preset conditions, controls the liquid hydrogen flow measurement module 3 to measure the liquid hydrogen flow, and controls the heater 6 to heat the liquid nitrogen in the liquid nitrogen container 4 so that the temperature of the liquid hydrogen at the output end of the liquid hydrogen flow measurement module 3 is within a preset range.

[0025] Exemplarily, the preset condition can be a pressure condition suitable for liquid hydrogen flow measurement. The content of the preset condition can be based on experimental determination. The implementation of this application does not limit the specific content of the preset condition, as long as it is reasonable. The preset range can be a temperature range that meets the liquid hydrogen flow measurement. The embodiment of this application does not limit the specific content of the preset range, and those skilled in the art can determine it according to needs. In the embodiment of the present application, when it is necessary to measure the liquid hydrogen flow, the control module controls the liquid hydrogen dewar 2 to pressurize the liquid hydrogen, ensuring the stability of the liquid hydrogen pressure flowing into the liquid hydrogen flow measurement module 3. The control module controls the heater 6 to heat the liquid nitrogen in the liquid nitrogen container 4, adjusts the ratio of nitrogen and liquid nitrogen in the liquid nitrogen container 4, and adjusts the contact area between the nitrogen heating coil 5 and the liquid nitrogen, thereby achieving control of the liquid hydrogen temperature in the nitrogen heating coil 5, ensuring that the possibility of vaporization of the liquid hydrogen flowing out of the output end of the liquid hydrogen flow measurement module 3 due to excessive temperature is reduced, ensuring the stability of the liquid hydrogen pressure at the output end, and ensuring the accuracy of the flow measurement result of the liquid hydrogen flow measurement device. In the embodiment of the present application, the output end of the nitrogen heating coil 5 can be connected to a liquid hydrogen processing and storage unit to achieve the processing, transportation and storage of liquid hydrogen.

[0026] The embodiment of the present application provides a low-temperature measurement system for liquid hydrogen flow under renewable energy hydrogen production conditions. By arranging a liquid hydrogen dewar between the liquid hydrogen supply device and the liquid hydrogen flow measurement module, and using a control module to control the liquid hydrogen dewar to pressurize the liquid hydrogen, the stability of the liquid hydrogen pressure flowing into the liquid hydrogen flow measurement module is ensured. By arranging a liquid nitrogen container at the output end of the liquid hydrogen flow measurement module, and using the control module to control a heater to heat the liquid nitrogen in the liquid nitrogen container, the pressure of the liquid hydrogen at the output end of the liquid hydrogen flow measurement module is kept within a preset range, thereby ensuring the stability of the temperature of the liquid hydrogen flowing out of the liquid hydrogen flow measurement module, reducing the possibility of vaporization of the liquid hydrogen flowing out of the output end of the liquid hydrogen flow measurement module, and ensuring the stability of the liquid hydrogen pressure at the output end. Under the premise that the liquid hydrogen pressure at the input and output of the liquid hydrogen flow measurement module is stable, the accuracy of the low-temperature liquid hydrogen flow measured by the liquid hydrogen flow measurement device can be guaranteed.

[0027] In some optional embodiments, the schematic diagram of the liquid hydrogen flow measurement system can be as follows: Figure 2 As shown, the system further includes a vaporizer 7; the output end of the nitrogen heating coil 5 is connected to the input end of the vaporizer 7. Exemplarily, after the liquid hydrogen flows out of the output end of the nitrogen heating coil 5, it flows into the vaporizer 7, which is used to reheat the liquid hydrogen.

[0028] The system also includes a reflux valve 8, an exhaust line 21, a first line, and a second line. The first line includes a first control valve 22 and a standard flowmeter 23, and the second line includes a second control valve 24 and a hydrogen storage tank 25. The output of the vaporizer 7 is connected to the input of the exhaust line 21 via the reflux valve 8, and the output of the exhaust line 21 is connected to the input of the liquid hydrogen supply device 1. The output of the vaporizer 7 is connected to the input of the standard flowmeter 23 via the first control valve 22, and the output of the standard flowmeter 23 is connected to the input of the liquid hydrogen supply device 1. The output of the vaporizer 7 is connected to the hydrogen storage tank 25 via the second control valve 24.

[0029] The system also includes a bypass line connected in parallel with the liquid hydrogen flow measurement module 3. The bypass line includes a bypass valve 26. The liquid hydrogen flow measurement module 3 includes a measurement control valve 27 and a liquid hydrogen flow measurement device 28. The control module is further configured to control the measurement control valve 27 to close and the bypass valve 26 to open upon receiving a test instruction for liquid hydrogen flow measurement.

[0030] For example, in an embodiment of the present application, at the start of the flow measurement test phase, the control module controls the measurement control valve 27 to close, controls the bypass valve 26 to open, and controls the reflux valve 8 to open. The low-temperature liquid hydrogen flows from the liquid hydrogen dewar 2 through the bypass line and then enters the nitrogen heating coil 5, the vaporizer 7, the reflux valve 8 and the exhaust line 21 in sequence and is discharged to the liquid hydrogen supply device 1. This process can achieve preliminary cooling.

[0031] When it is not necessary to measure the liquid hydrogen flow rate under low temperature conditions, the reflux valve 8 and the bypass valve 26 are closed, and the measurement control valve 27 is opened. The low-temperature fluid is discharged through the liquid hydrogen flow measuring device 28, the nitrogen heating coil 5, the vaporizer 7 and the standard flow meter 23. The hydrogen flow rate can be measured using the standard flow meter data and then returned to the liquid hydrogen supply device 1.

[0032] During low-temperature flow measurement, the reflux valve 8 and the bypass valve 26 are closed, the measurement control valve 27 is opened, the first control valve 22 is closed, and the second control valve 24 is opened. The low-temperature fluid flows into the hydrogen storage tank 25 through the liquid hydrogen flow measuring device 28, the nitrogen heating coil 5, and the vaporizer 7.

[0033] The liquid hydrogen dewar 2 includes a self-pressurizing valve 29 and a safety valve 31. The control module controls the self-pressurizing valve 29 to open so that the liquid hydrogen dewar pressurizes the liquid hydrogen. A nitrogen replenishing valve 32 is also provided in the liquid nitrogen container 4.

[0034] The following is a specific example of a liquid hydrogen flow rate low-temperature measurement system under renewable energy hydrogen production conditions provided by the present application.

[0035] Example:

[0036] The liquid hydrogen dewar is equipped with a self-pressurizing valve and a safety valve. The liquid hydrogen dewar is connected to a measuring pipeline, which contains a test control valve and a liquid hydrogen flow measurement device. The measuring pipeline is also connected to a nitrogen heating coil. Between the liquid hydrogen dewar and the nitrogen heating coil, a bypass pipeline is connected in parallel to the measuring pipeline, and the bypass pipeline contains a bypass valve. The nitrogen heating coil is partially immersed in a liquid nitrogen container, which is equipped with a heater and a nitrogen replenishment valve to cool the gas and isolate external heat from the liquid hydrogen. The nitrogen heating coil is connected to a vaporizer, which is connected to an exhaust pipeline. The exhaust pipeline contains a reflux valve, and a first pipeline and a second pipeline are connected in parallel to the exhaust pipeline. The first pipeline contains a first control valve and a standard flowmeter, and the second pipeline contains a second control valve and a hydrogen storage tank. At the beginning of the test phase, the test control valve is closed and the bypass valve is opened to allow the cryogenic fluid to pass through the bypass valve into the nitrogen heating coil, vaporizer and exhaust pipe, and finally discharged to the liquid hydrogen supply device through the reflux valve of the exhaust pipe. This process can achieve initial cooling.

[0037] When direct measurement is required, close the bypass valve and the reflux valve, open the test control valve and the first control valve, and the cryogenic fluid is discharged through the liquid hydrogen flow measuring device, the nitrogen heating coil, the vaporizer, and the standard flow meter. The hydrogen flow can be measured using the standard flow meter data and then returned to the liquid hydrogen supply device. When low-temperature measurement is required, close the first control valve and open the second control valve. The cryogenic fluid flows through the liquid hydrogen flow measuring device, the nitrogen heating coil, and the vaporizer into the hydrogen storage tank, etc. When the liquid hydrogen supply device is operating, liquid hydrogen flows into the liquid hydrogen dewar. At this time, the test control valve is opened. Since the internal volume of the liquid hydrogen dewar is fixed, the liquid hydrogen will flow out under the pressure inside the dewar after flowing in, and then flow into the liquid hydrogen flow measuring device through the measuring pipeline. At this time, the pressure and temperature are relatively stable. The pressure difference before and after the liquid hydrogen flow measuring device under this flow rate is then obtained. The liquid hydrogen then enters the nitrogen heating coil, where the liquid inside comes into contact with the nitrogen gas and liquid nitrogen inside the liquid nitrogen container, raising its temperature. When the liquid inside the liquid nitrogen container is high, the heater is turned on to heat the liquid nitrogen and control the temperature of the liquid hydrogen in the nitrogen heating coil. It is important to note that the temperature inside the liquid nitrogen container is below room temperature. After the hydrogen reaches 70K, it enters the vaporizer and then returns to room temperature. At this point, the second control valve is opened, allowing the hydrogen to enter the hydrogen storage tank for storage. After the cryogenic measurement is completed, all valves are closed and the bypass valve is opened. The liquid hydrogen supply unit continues to operate, allowing the liquid hydrogen to flow into the liquid hydrogen dewar and then through the bypass line into the nitrogen heating coil. The liquid inside the nitrogen heating coil comes into contact with the nitrogen gas and liquid nitrogen inside the liquid nitrogen container, reheating the liquid inside the nitrogen heating coil. When the liquid inside the liquid nitrogen container is high, the heater is turned on to heat the liquid nitrogen and control the temperature of the liquid hydrogen in the nitrogen heating coil. It is important to note that the temperature inside the liquid nitrogen container is below room temperature. After the liquid hydrogen in the nitrogen heating coil is reheated to 70K, it enters the vaporizer. The first control valve is then opened, allowing it to flow into a standard flowmeter. The pressure differential across the standard flowmeter at this flow rate is measured and mapped to the pressure differential during low-temperature flow measurement by the liquid hydrogen flow measurement device. Hydrogen is then produced by the liquid hydrogen supply device. If the liquid hydrogen supply device loses its hydrogen source due to energy fluctuations, all valves are closed and the second control valve is opened. The hydrogen inside the hydrogen storage tank flows through the second control valve into the liquid hydrogen supply device, continuing to produce liquid hydrogen and flowing into the liquid hydrogen dewar. A booster pump can also be installed on the hydrogen storage tank.

[0038] The system provided by the present invention provides a low-temperature measurement environment for liquid hydrogen cryogenic flow measurement, provides a reference for the measurement process after hydrogen liquefaction under renewable energy hydrogen production conditions, reduces measurement cooling loss, and avoids errors and lags that may exist in liquid hydrogen cryogenic flow measurement at room temperature, effectively analyzing the low-temperature flow of liquid hydrogen. This measurement process uses both direct measurement and indirect measurement methods, which can effectively adapt to various low-temperature liquid hydrogen flow measurement and analysis situations. It can ensure the continuous operation of renewable energy hydrogen production under different working conditions and avoid cooling loss during flow measurement and analysis. The liquid hydrogen dewar can provide a larger volume for liquid hydrogen storage, reducing pressure fluctuations at the front end of the liquid hydrogen flow measurement device. The nitrogen heating coil can reduce pressure fluctuations at the rear end of the liquid hydrogen flow measurement device, ensuring that a good pressure condition is maintained during the measurement process. In addition, the nitrogen heater can regulate the ratio of liquid nitrogen and nitrogen gas inside the liquid nitrogen container, and maintain a constant contact area between the nitrogen heating coil and the low-temperature nitrogen and liquid nitrogen for the stability of the internal pressure of the liquid nitrogen container. The heating coil is inside the liquid nitrogen container, and it contacts the low-temperature nitrogen and liquid nitrogen respectively. Through temperature stratification and curved pipe arrangement, it can effectively isolate the external heat leakage, achieve a gas seal effect, and avoid the situation where the liquid hydrogen flow rate is small or there is no liquid hydrogen under the conditions of renewable energy hydrogen production, and the outer room temperature hydrogen flows into the liquid hydrogen flow measurement and analysis device, resulting in a large amount of heat leakage. The system provided in the embodiment of the present application does not involve yield. From the perspective of quality, it can improve the measurement accuracy of the hydrogen liquefaction rate. The current liquid level measurement accuracy is about 1%. For a 10,000L container, the liquefier liquefaction volume is about 70,000L per day, about 3,000L per hour, corresponding to an error of 30% per hour. It is expected that the measurement accuracy can be improved to about 5% by using low-temperature flow measurement.

[0039] Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention. Such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A low-temperature measurement system for liquid hydrogen flow under renewable energy hydrogen production conditions, characterized in that: The system includes: a liquid hydrogen supply device, a liquid hydrogen dewar, a liquid hydrogen flow measurement module, a liquid nitrogen container and a control module; The output end of the liquid hydrogen supply device is connected to the input end of the liquid hydrogen Dewar, and the liquid hydrogen supply device is used to produce liquid hydrogen; The output end of the liquid hydrogen dewar is connected to the input end of the liquid hydrogen flow measurement module; The liquid nitrogen container is provided with a nitrogen heating coil and a heater, and the output end of the liquid hydrogen flow measurement module is connected to the input end of the nitrogen heating coil; The control module is respectively connected to the liquid hydrogen dewar, the liquid hydrogen flow measurement module, and the heater, and is used to control the liquid hydrogen dewar to pressurize the liquid hydrogen when receiving a liquid hydrogen flow measurement instruction, so that the liquid hydrogen pressure in the liquid hydrogen dewar meets the preset conditions, control the liquid hydrogen flow measurement module to measure the liquid hydrogen flow, and control the heater to heat the liquid nitrogen in the liquid nitrogen container so that the temperature of the liquid hydrogen at the output end of the liquid hydrogen flow measurement module is within a preset range.

2. The system according to claim 1, wherein: The system further includes a vaporizer, and the output end of the nitrogen heating coil is connected to the input end of the vaporizer.

3. The system according to claim 2, characterized in that The system includes a reflux valve and an exhaust pipeline; The output end of the vaporizer is connected to the input end of the exhaust pipeline through the reflux valve, and the output end of the exhaust pipeline is connected to the input end of the liquid hydrogen supply device.

4. The system according to claim 3, characterized in that The system further includes a first pipeline including a first control valve and a standard flow meter; The output end of the vaporizer is connected to the input end of the standard flow meter through a first control valve, and the output end of the standard flow meter is connected to the input end of the liquid hydrogen supply device.

5. The system according to claim 4, characterized in that The system further includes a second pipeline comprising a second control valve and a hydrogen storage tank; The output end of the vaporizer is connected to the hydrogen storage tank through the second control valve.

6. The system according to claim 5, characterized in that The system further includes a bypass line connected in parallel with the liquid hydrogen flow measurement module. The bypass line includes a bypass valve, and the liquid hydrogen flow measurement module includes a measurement control valve.

7. The system according to claim 6, characterized in that The control module is further configured to control the measurement control valve to close and the bypass valve to open when receiving a test instruction for liquid hydrogen flow measurement.

8. The system according to any one of claims 1 to 7, characterized in that The liquid hydrogen dewar includes a self-pressurizing valve and a safety valve; The control module controls the self-pressurizing valve to open so that the liquid hydrogen dewar pressurizes the liquid hydrogen.

9. The system according to any one of claims 1 to 7, characterized in that The liquid nitrogen container is also provided with a nitrogen replenishing valve.

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