A low-energy-consumption and high-efficiency gaseous hydrogen filling method based on parallel regulation of multiple expanders

Abstract

A low-energy consumption and high-efficiency gaseous hydrogen filling system based on parallel regulation of multiple expanders. It relates to the field of hydrogen energy technology. The present invention solves the problems of low efficiency of a single expander, insufficient adaptability of a series-connected expander unit, and unsatisfactory temperature control in the prior art, significantly reducing the hydrogenation energy consumption and improving the hydrogenation efficiency and safety. It includes a high-pressure storage tank, an expander unit, a controller, a hydrogen filling machine, and a generator. The expander unit is composed of at least two expanders arranged in parallel, and each expander has a different working pressure ratio range, suitable for hydrogenation working conditions with wide pressure ratio changes. The controller monitors the pressure ratio at the inlet and outlet of the expander in real time, dynamically selects the optimal expander, and adjusts its rotational speed to the rotational speed range corresponding to the maximum efficiency, ensuring the high-efficiency operation of the system within a wide pressure ratio range. The hydrogen filling machine fills the pre-cooled hydrogen into the on-vehicle hydrogen storage tank, and the generator converts the mechanical energy recovered by the expander into electrical energy. It is applicable to hydrogen filling stations for hydrogen fuel cell vehicles.

Description

Technical Field

[0001] The invention relates to the field of hydrogen energy technology, and in particular to a low-energy consumption and high-efficiency gas-hydrogen filling system based on parallel control of multiple expanders. Background Art

[0002] As an important alternative to traditional fuel vehicles, hydrogen fuel cell vehicles have the advantages of zero emissions and high efficiency, and are considered to be a key component of the future sustainable transportation system. However, the promotion of hydrogen fuel cell vehicles depends on a sound hydrogen refueling infrastructure, especially efficient and low-energy hydrogen refueling stations. The core function of a hydrogen refueling station is to safely and quickly fill high-pressure hydrogen into the on-board hydrogen storage tank. In this process, the temperature control of hydrogen is crucial, because the temperature rise effect of the on-board hydrogen storage tank will significantly affect the performance of the tank and the hydrogen refueling efficiency. If the hydrogen temperature is too high, it may cause the hydrogen storage tank material to fail or cause safety hazards. Therefore, the maximum temperature of the on-board hydrogen storage tank is usually controlled within 85°C.

[0003] To meet this requirement, existing hydrogenation systems usually use precooling technology to reduce the temperature of hydrogen. However, traditional precooling systems (such as mechanical refrigeration or liquid nitrogen cooling) have high energy consumption and complex equipment, which increases the construction and operation costs of hydrogenation stations. In order to reduce energy consumption and improve hydrogenation efficiency, researchers have proposed a solution to recover energy through an expander. Through the isentropic expansion process, the expander can not only reduce the temperature of hydrogen, but also recover part of the expansion work and convert it into electrical energy for system use or to be incorporated into the power grid.

[0004] Current status of existing technology research

[0005] 1. Single expander energy recovery solution:

[0006] In the prior art, researchers such as Yoshida and Chen et al. proposed a scheme to recover energy through a single expander. This scheme uses the expander to recover energy during the expansion of hydrogen, lower the temperature of hydrogen, and thus reduce the energy consumption of the pre-cooling system. For example, Yoshida et al. proposed a hydrogenation system integrating a single expander, which reduces the temperature of hydrogen to a safe range and recovers part of the energy through the isentropic expansion process of the expander.

[0007] However, the design of a single expander is usually optimized for a specific pressure ratio range, and in the actual hydrogenation process, the inlet and outlet pressure ratio of the expander will continue to change as the hydrogenation process progresses. For example, in a 70MPa hydrogenation system, the pressure ratio range may change from 1.2 to 18. It is difficult for a single expander to maintain efficient operation in such a wide pressure ratio range, resulting in a significant decrease in efficiency under certain conditions, or even failure to work properly.

[0008] 2. Series expansion unit solution:

[0009] In order to cope with the high pressure ratio working conditions, the solution of series expansion units is usually adopted in industrial applications. The series expansion unit expands the high-pressure hydrogen in stages through a multi-stage expansion process, so that the pressure gradient of each stage of expansion is small, thereby reducing energy loss. For example, some industrial gas processing systems use two-stage or three-stage series expansion units to improve energy recovery efficiency.

[0010] However, the design of the series expansion unit requires that the pressure difference of each stage of the expansion unit is basically stable, which is suitable for working conditions with small pressure ratio changes. During the hydrogenation process, the pressure ratio of the expansion unit will change rapidly as the hydrogenation process progresses. The series expansion unit is difficult to effectively cope with such rapidly changing working conditions, resulting in a decrease in system efficiency.

[0011] Although the existing single expander and series expander solutions can reduce the energy consumption of the hydrogenation system and improve the energy recovery efficiency to a certain extent, they still have the following technical problems:

[0012] 1. Limitations of a single expander:

[0013] It is difficult for a single expander to maintain efficient operation within a wide range of pressure ratios. During the hydrogenation process, the pressure ratio changes from large to small, and a single expander cannot maintain high efficiency throughout the entire refueling process, resulting in a decrease in energy recovery efficiency and an increase in system energy consumption.

[0014] 2. Insufficient adaptability of series expansion units:

[0015] Although the series expansion unit is suitable for large pressure ratio conditions, its design requires that the pressure difference of each stage of the expansion unit is basically stable, which is not suitable for hydrogenation processes with rapidly changing pressure ratios. During the hydrogenation process, the rapid change in pressure ratio will cause the efficiency of the series expansion unit to decrease, or even fail to work properly.

[0016] 3. Temperature control is not ideal:

[0017] In the prior art, a single expander and a series of expander groups have limited effect on the temperature control of hydrogen during the hydrogenation process, which may cause the temperature of the on-board hydrogen storage tank to exceed the safety threshold (85°C), affecting the hydrogenation efficiency and the safety of the hydrogen storage tank. Summary of the invention

[0018] In order to solve the technical problems existing in the prior art, that is, in the design of the existing series expansion unit, there are limitations on a single expansion unit, insufficient adaptability of the series expansion unit, and unsatisfactory temperature control, the technical solution provided by the present invention is:

[0019] A low energy consumption and high efficiency gas hydrogen filling system based on parallel control of multiple expanders, comprising:

[0020] High-pressure storage tanks, used to store high-pressure hydrogen;

[0021] An expansion unit, including at least two expanders arranged in parallel, each expander having a different operating pressure ratio range, and the inlet of the expansion unit is connected to the high-pressure storage tank through a pipeline;

[0022] A controller, used to monitor the pressure ratio at the inlet and outlet of the expander in real time, dynamically select the corresponding expander according to the pressure ratio to operate, and at the same time adjust the rotational speed of the selected expander to the rotational speed range corresponding to its maximum efficiency;

[0023] A hydrogen filling machine, connected to the outlet of the expansion unit, for filling the hydrogen pre-cooled by the expansion unit into the on-vehicle hydrogen storage tank;

[0024] A generator, respectively connected to each of the expanders, for converting the mechanical energy recovered by the expander into electrical energy.

[0025] Furthermore, a preferred embodiment is provided. A control valve and a pressure gauge are provided on the pipeline connecting the inlet of the expansion unit and the high-pressure storage tank.

[0026] Furthermore, a preferred embodiment is provided. The high-pressure storage tank includes a high-pressure hydrogen storage tank with a pressure of 90 MPa and a volume of 2.1 m 3 .

[0027] Furthermore, a preferred embodiment is provided. The expander in the expansion unit is a radial flow turbine expander, including a first expander and a second expander,

[0028] The operating pressure ratio range of the first expander is 2.62 - 18, the isentropic efficiency is 50% - 80%, and the optimal rotational speed range is 180000 - 230000 rev / min;

[0029] The operating pressure ratio range of the second expander is 1.25 - 2.62, the isentropic efficiency is 50% - 75%, and the optimal rotational speed range is 90000 - 176000 rev / min.

[0030] Furthermore, a preferred embodiment is provided. The generator is connected to the outlet of the expansion unit through a coupling, and the electrical energy output by the generator is converted into grid-compatible alternating current through a rectifier-inverter, or stored in an energy storage power station.

[0031] Furthermore, a preferred embodiment is provided. The system further includes a temperature control module, which dynamically adjusts the temperature of the hydrogen at the outlet of the expander not to exceed 85 °C through the controller.

[0032] Based on the same inventive concept, the present invention also provides a low-energy consumption and high-efficiency gaseous hydrogen filling method based on parallel control of multiple expanders. The method is implemented based on the above-mentioned system and includes:

[0033] Steps for real-time monitoring of the inlet and outlet pressure ratio of the expansion unit to obtain current pressure ratio data;

[0034] Steps for determining the optimal expander and its corresponding optimal speed range at the current pressure ratio according to a preset pressure ratio - speed efficiency curve;

[0035] Steps for dynamically switching to the optimal expander and adjusting its speed to the optimal speed range to make the expander operate at maximum efficiency;

[0036] Steps for real-time monitoring of the hydrogen temperature at the outlet of the expansion unit and triggering the adjustment of the expander speed or the switching of the expander when the detected temperature exceeds a preset threshold;

[0037] Steps for converting the mechanical energy recovered by the expander into electrical energy through a generator and storing or incorporating the electrical energy into the power grid;

[0038] Steps for adjusting the filling rate of the hydrogen filling machine according to the real-time pressure and temperature data of the on-vehicle hydrogen storage tank to ensure that the hydrogen temperature does not exceed 85°C during the filling process.

[0039] Based on the same inventive concept, the present invention also provides a computer storage medium for storing a computing program, and when the computer program is read by a computer, the computer executes the method described above.

[0040] Based on the same inventive concept, the present invention also provides a computer comprising a processor and a storage medium, and when the processor reads the computer program stored in the storage medium, the computer executes the method described above.

[0041] Based on the same inventive concept, the present invention also provides a computer program product, which is a computer program, and when the computer program is executed, the method described above is implemented.

[0042] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows:

[0043] The dynamic switching of multiple parallel expanders ensures the efficient operation of the system within a wide pressure ratio range. During the hydrogenation process, the inlet and outlet pressure ratio of the expander changes continuously as hydrogenation progresses, and it is difficult for a single expander to maintain efficient operation throughout the pressure ratio range. In the present invention, multiple parallel expanders are used, and each expander is optimized for a different pressure ratio range to ensure that the optimal expander operates under different pressure ratio conditions. For example, the first expander is suitable for a higher pressure ratio range (2.62 - 18), while the second expander is suitable for a lower pressure ratio range (1.25 - 2.62). Through dynamic switching, the system can maintain efficient operation throughout the filling process, avoiding the problem of efficiency decline of a single expander under off-design conditions. Compared with the single expander scheme in existing research, the present invention significantly improves the operation efficiency of the system within a wide pressure ratio range.

[0044] By adjusting the rotational speed of the expander in real time through a controller, it is ensured that each expander operates at the maximum efficiency, significantly improving the energy recovery efficiency. The controller in the present invention monitors the inlet and outlet pressure ratio of the expander and adjusts the rotational speed of the expander in real time according to the relationship between the pressure ratio and rotational speed at the maximum efficiency, so that it always operates within the optimal rotational speed range. For example, the optimal rotational speed range of the first expander is 180000 - 230000 rev / min, and the optimal rotational speed range of the second expander is 90000 - 176000 rev / min. This real-time adjustment mechanism ensures that each expander can operate at the highest efficiency under its design conditions, thereby recovering more energy. Compared with the single expander scheme in existing research, the energy recovery efficiency of the present invention is significantly improved, and the total energy recovered by the system has increased from 1923 kJ (single expander scheme 1) and 2377 kJ (single expander scheme 2) to 3067 kJ (parallel expander unit scheme 3).

[0045] The design of the parallel expander unit effectively controls the temperature of the on-vehicle hydrogen storage tank, ensuring the safety of the hydrogenation process. During the hydrogenation process, the temperature control of hydrogen is crucial, and too high a temperature may cause the material of the on-vehicle hydrogen storage tank to fail or pose a safety hazard. In the present invention, multiple parallel expanders are used to pre-cool hydrogen to ensure that the temperature of hydrogen is always within a safe range during the filling process. For example, in the embodiment, for scheme 3 with a parallel expander unit, the final temperature of the on-vehicle hydrogen storage tank is 63.95 °C, while the final temperatures of single expander schemes 1 and 2 are 84.33 °C and 84.56 °C respectively. Compared with existing research, the present invention significantly reduces the final temperature of the on-vehicle hydrogen storage tank through the design of the parallel expander unit, ensuring the safety of the hydrogenation process.

[0046] The energy recovered by the expander is converted into electrical energy through a generator, further reducing the energy consumption of the system. In the present invention, the expander is not only used to cool hydrogen, but also can recover expansion work through an isentropic expansion process, and convert the recovered energy into electrical energy through the connected generator. This electrical energy can be incorporated into the power grid or stored in an energy storage power station for subsequent use. For example, in the embodiment, the total energy recovered by the expander unit is 3067 kJ, which is significantly higher than 1923 kJ and 2377 kJ of the single expander scheme. Compared with the prior art solutions that only rely on the pre-cooling system, the present invention further reduces the energy consumption of the system and improves the overall energy efficiency through the energy recovery mechanism.

[0047] In summary, the present invention significantly improves the operation efficiency, energy recovery ability and safety of the hydrogen refueling system through the dynamic switching of multiple parallel expanders, the real-time adjustment of the rotational speed by the controller, the optimization of temperature control and the energy recovery mechanism, and solves the problems of low efficiency, insufficient energy recovery and unsatisfactory temperature control of a single expander and a series expander unit in a wide pressure ratio range in the prior art.

[0048] It is suitable for application in the work of low-energy-consumption and high-efficiency gaseous hydrogen refueling with parallel regulation of multiple expanders. Brief Description of the Drawings

[0049] Figure 1 It is a schematic structural diagram of the parallel expander hydrogen refueling system provided by the present invention;

[0050] Figure 2 It is a predicted efficiency change curve of the expander with a design pressure ratio of 1.3 under off-design conditions;

[0051] Figure 3 It is a predicted mass flow rate change curve of the expander with a design pressure ratio of 1.3 under off-design conditions;

[0052] Figure 4 It is a predicted efficiency change curve of the expander with a design pressure ratio of 3 under off-design conditions;

[0053] Figure 5 It is a predicted mass flow rate change curve of the expander with a design pressure ratio of 3 under off-design conditions;

[0054] Figure 6 It is a curve of the actual operating efficiency of the expander related to the present invention changing with time;

[0055] Figure 7 It is a curve of the total output energy of the expander related to the present invention changing with time;

[0056] Figure 8 It is a curve of the temperature of the on-vehicle storage tank changing with time when the system related to the present invention refuels a vehicle.

[0057] Among them, 1. High-pressure storage tank; 2. First control valve; 3. First expander; 4. First generator; 5. Second control valve; 6. Second expander; 7. Second generator; 8. First pressure gauge; 9. First temperature gauge; 10. Hydrogen refueling machine; 11. Controller; 12. On-vehicle hydrogen storage tank; 13. Second pressure gauge; 14. Third pressure gauge. Specific embodiments

[0058] To make the advantages and beneficial effects of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention will be further described in detail with reference to the accompanying drawings. Specifically:

[0059] Embodiment 1. This embodiment provides a low-energy-consumption and high-efficiency gaseous hydrogen refueling system based on parallel regulation of multiple expanders, including:

[0060] A high-pressure storage tank 1 for storing high-pressure hydrogen;

[0061] An expander unit, including at least two expanders arranged in parallel, each expander having a different working pressure ratio range, and the inlet of the expander unit is connected to the high-pressure storage tank 1 through a pipeline;

[0062] A controller 11 for real-time monitoring of the pressure ratio at the inlet and outlet of the expander, dynamically selecting the corresponding expander to work according to the pressure ratio, and at the same time adjusting the speed of the selected expander to the speed range corresponding to its maximum efficiency;

[0063] A hydrogen refueling machine 10, connected to the outlet of the expander unit, for refueling the hydrogen pre-cooled by the expander unit into the on-vehicle hydrogen storage tank 12;

[0064] Generators, respectively connected to each of the expanders, for converting the mechanical energy recovered by the expanders into electrical energy.

[0065] Embodiment 2. This embodiment further limits the low-energy-consumption and high-efficiency gaseous hydrogen refueling system based on parallel regulation of multiple expanders provided in Embodiment 1. A control valve and a pressure gauge are provided on the pipeline connecting the inlet of the expander unit and the high-pressure storage tank 1.

[0066] Embodiment 3. This embodiment further limits the low-energy-consumption and high-efficiency gaseous hydrogen refueling system based on parallel regulation of multiple expanders provided in Embodiment 1. The high-pressure storage tank 1 includes a high-pressure hydrogen storage tank with a pressure of 90 MPa and a volume of 2.1 m 3 .

[0067] Embodiment 4. This embodiment further limits the low-energy-consumption and high-efficiency gaseous hydrogen refueling system based on parallel regulation of multiple expanders provided in Embodiment 1. The expanders in the expander unit are radial flow turbine expanders, including a first expander 3 and a second expander 6.

[0068] The operating pressure ratio range of the first expander 3 is 2.62 - 18, the isentropic efficiency is 50% - 80%, and the optimal speed range is 180,000 - 230,000 rev / min;

[0069] The operating pressure ratio range of the second expander 6 is 1.25 - 2.62, the isentropic efficiency is 50% - 75%, and the optimal speed range is 90,000 - 176,000 rev / min.

[0070] Embodiment 5: This embodiment further limits a low - energy - consumption and high - efficiency gaseous hydrogen filling system based on parallel regulation of multiple expanders provided in Embodiment 1. The generator is connected to the outlet of the expander set through a coupling, and the electric energy output by the generator is converted into grid - compatible alternating current through a rectifier - inverter, or stored in an energy storage power station.

[0071] Embodiment 6: This embodiment further limits a low - energy - consumption and high - efficiency gaseous hydrogen filling system based on parallel regulation of multiple expanders provided in Embodiment 1. The system further includes a temperature control module, and the controller 11 dynamically adjusts the temperature of the hydrogen gas at the outlet of the expander not to exceed 85°C.

[0072] Embodiment 7: This embodiment provides a low - energy - consumption and high - efficiency gaseous hydrogen filling method based on parallel regulation of multiple expanders. The method is implemented based on the system provided in Embodiment 1 and includes:

[0073] The step of real - time monitoring the inlet and outlet pressure ratios of the expander set to obtain the current pressure ratio data;

[0074] The step of determining the optimal expander and its corresponding optimal speed range at the current pressure ratio according to the preset pressure ratio - speed efficiency curve;

[0075] The step of dynamically switching to the optimal expander and adjusting its speed to the optimal speed range to make the expander operate at the maximum efficiency;

[0076] The step of real - time monitoring the temperature of the hydrogen gas at the outlet of the expander set, and triggering the step of adjusting the expander speed or switching the expander when the detected temperature exceeds the preset threshold;

[0077] The step of converting the mechanical energy recovered by the expander into electric energy through a generator and storing or incorporating the electric energy into the grid;

[0078] The step of adjusting the filling rate of the hydrogen filling machine 10 according to the real - time pressure and temperature data of the on - vehicle hydrogen storage tank 12 to ensure that the temperature of the hydrogen gas does not exceed 85°C during the filling process.

[0079] Specifically:

[0080] Step 1: Monitor the inlet and outlet pressure ratio of the expansion unit in real time to obtain the current pressure ratio data

[0081] Pressure ratio monitoring device: Install high-precision pressure sensors (such as the second pressure gauge 13, the third pressure gauge 14, and the first pressure gauge 8) in the inlet and outlet pipelines of the expansion unit to collect the inlet pressure and outlet pressure in real time.

[0082] Data acquisition and processing: The controller 11 reads the pressure data at a frequency of 10 times per second and calculates the current pressure ratio. After filtering, the data is stored in the local database for subsequent analysis and control decisions.

[0083] Abnormal handling: If the detected pressure fluctuation exceeds ±5% (such as pipeline blockage or leakage), the controller immediately triggers an alarm and pauses the filling process.

[0084] Output: The real-time pressure ratio data and system status information are transmitted to the controller 11.

[0085] Step 2: Determine the optimal expander and its corresponding optimal speed range at the current pressure ratio according to the preset pressure ratio - speed efficiency curve

[0086] Modeling of the pressure ratio - speed efficiency curve: Based on experimental data and simulation analysis, a three-dimensional relationship curve of the efficiency - pressure ratio - speed of each expander is established in advance. For example, the speed corresponding to the peak efficiency of the first expander 3 at a pressure ratio of 2.62 - 18 is 180000 - 230000 rev / min, and the speed corresponding to the peak efficiency of the second expander 6 at a pressure ratio of 1.25 - 2.62 is 90000 - 176000 rev / min (as Figure 2 、 Figure 4 shown).

[0087] Dynamic matching algorithm: The controller 11 traverses the preset curve according to the current pressure ratio and selects the expander with the highest efficiency. For example, when the pressure ratio ≥ 2.62, the first expander 3 is selected, and when the pressure ratio < 2.62, the second expander 6 is switched to.

[0088] Priority logic: If the pressure ratio is in the overlapping area of the efficiency curves of two expanders (such as a pressure ratio of 2.0 - 2.62), the expander with lower energy consumption is selected according to the historical operation data.

[0089] Output: The optimal expander number and its target speed range under the current working conditions.

[0090] Step 3: Dynamically switch to the optimal expander and adjust its speed to the optimal speed range to make the expander operate at the maximum efficiency

[0091] Switching control logic: The controller 11 sends commands to the corresponding control valves to close the inlet valves of the non-operating expanders and open the inlet valves of the target expanders simultaneously. The switching process is completed within 200 ms to avoid pressure mutations.

[0092] Speed regulation: The PID control algorithm is used to adjust the expander speed in real time. For example, when the target speed of the first expander 3 is 200000 rev / min, the controller adjusts the motor drive signal through the frequency converter to control the speed error within ±1%.

[0093] Efficiency monitoring: If the actual efficiency is lower than 90% of the preset peak value, trigger re-matching of the pressure ratio - speed curve or switching of the expander.

[0094] Output: The target expander operates at the optimal speed, and the output hydrogen pressure drops to 5 - 70 MPa, and the temperature drops to 200 - 280 K.

[0095] Step 4: Real-time monitor the hydrogen temperature at the outlet of the expander unit. When the detected temperature exceeds the preset threshold, trigger the adjustment of the expander speed or switching of the expander.

[0096] Temperature monitoring device: Install a platinum resistance temperature sensor (the first temperature measuring table 9) in the outlet pipeline of the expander unit to collect the hydrogen temperature in real time with an accuracy of ±0.5 K.

[0097] Threshold determination: The preset safety threshold is 280 K. If the hydrogen temperature is above 280 K, the controller 11 activates the emergency strategy:

[0098] First-level response: Increase the current expander speed to a higher speed section of the efficiency curve (for example, the first expander is increased from 200000 rev / min to 220000 rev / min) to enhance the refrigeration effect.

[0099] Second-level response: If the temperature is still above the standard after the first-level response, immediately switch to another expander and re-match the speed.

[0100] Historical data recording: All temperature over-standard events are recorded in the log for subsequent system optimization.

[0101] Output: The hydrogen temperature is stabilized at 200 - 280 K to ensure the safety of subsequent refueling.

[0102] Step 5: Convert the mechanical energy recovered by the expander into electrical energy through a generator and store the electrical energy or integrate it into the power grid. Energy conversion device: The expander is connected to a permanent magnet synchronous generator through a coupling to convert the expansion work into three-phase alternating current.

[0103] Power management:

[0104] Rectification and Inversion: The electric energy output by the generator is converted into direct current by a rectifier, and then adjusted to 50Hz / 220V alternating current by a grid-connected inverter and connected to the public power grid.

[0105] Energy storage backup: Part of the electrical energy is stored in a lithium battery pack (capacity 100kWh) for system self-powering or refueling needs during low-load periods at night.

[0106] Energy measurement: The smart meter counts the recovered energy in real time. The total recovered energy of the parallel unit (Scheme 3) in the embodiment reaches 3067kJ, which is more than 60% higher than that of the single expander solution.

[0107] Output: Recycled electric energy is used in the power grid or energy storage system, and the overall energy efficiency of the system is increased to 85%.

[0108] Step 6: According to the real-time pressure and temperature data of the onboard hydrogen storage tank 12, adjust the filling rate of the hydrogen filling machine 10 to ensure that the hydrogen temperature does not exceed 85°C during the filling process

[0109] Filling feedback control: The hydrogen filling machine 10 has built-in pressure sensors and temperature sensors to monitor the pressure and temperature of the on-board hydrogen storage tank 12 in real time.

[0110] Dynamic adjustment strategy:

[0111] Pressure matching: When the pressure of the on-board hydrogen storage tank approaches the target pressure (such as 70MPa), the filling rate is linearly reduced to avoid pressure shock.

[0112] Temperature protection: If the temperature of the on-board hydrogen storage tank is above 80 degrees Celsius, the speed reduction mode will be triggered, reducing the filling rate from 40g / s to 20g / s; if the temperature of the on-board hydrogen storage tank is above 85 degrees Celsius, the filling will be stopped immediately and the cooling system will be started.

[0113] Efficiency optimization: Analyze historical filling data through machine learning algorithms, predict the best filling curve, and further shorten the filling time (reduced by 25% in the embodiment).

[0114] Output: Hydrogen is safely filled into the on-board hydrogen storage tank, the temperature inside the tank is always ≤85℃, and the filling efficiency is increased to 98%.

[0115] Embodiment 8: This embodiment provides a computer storage medium for storing a computer program. When the computer program is read by a computer, the computer executes the method provided in embodiment 7.

[0116] Embodiment 9: This embodiment provides a computer, including a processor and a storage medium. When the processor reads a computer program stored in the storage medium, the computer executes the method provided in embodiment 7.

[0117] Embodiment Ten. This embodiment provides a computer program product. As a computer program, when the computer program is executed, it implements the method provided in Embodiment Seven.

[0118] Embodiment Eleven. In combination with Figure 1-8 this embodiment is described. In this embodiment, through specific embodiments, the above-provided technical solutions are further described in detail. Specifically:

[0119] Example 1

[0120] As Figure 1 shown, the present invention provides a low-energy consumption and high-efficiency gaseous hydrogen refueling system based on parallel regulation of multiple expanders. The system includes the following components: high-pressure storage tank 1, first control valve 2, first expander 3, first generator 4, second control valve 5, second expander 6, second generator 7, first pressure gauge 8, first temperature gauge 9, hydrogen refueling machine 10, controller 11, on-vehicle hydrogen storage tank 12, second pressure gauge 13, third pressure gauge 14; specifically, the high-pressure storage tank 1 is respectively connected to the first control valve 2 and the second control valve 5, the first control valve 2 is connected to the second pressure gauge 13, the second pressure gauge 13 is connected to the first expander 3, the first expander 3 is drivingly connected to the first generator 4, the first expander 3 is connected to the first pressure gauge 8, the second control valve 5 is connected to the third pressure gauge 14, the third pressure gauge 14 is connected to the second expander 6, the second expander 6 is drivingly connected to the second generator 7, the second expander 6 is connected to the first pressure gauge 8, and the expanders are respectively connected to the controller 11; the controller 11 is respectively connected to the second pressure gauge 13, the third pressure gauge 14, and the first pressure gauge 8. The controller 11 adjusts the expander to operate at the optimal speed by monitoring the pressure ratio at the inlet and outlet of the expander and according to the relationship between the pressure ratio and the speed at the maximum efficiency; the first pressure gauge 8, the first temperature gauge 9, and the hydrogen refueling machine 10 are sequentially connected to the on-vehicle hydrogen storage tank 12.

[0121] The following is an explanation of the operating principle of the low-energy consumption and high-efficiency gaseous hydrogen refueling system based on parallel regulation of multiple expanders:

[0122] The high-pressure storage tank 1 is used to store high-pressure hydrogen obtained through multi-stage compression. The high-pressure hydrogen enters the expander for subsequent processing after passing through the high-pressure storage tank 1.

[0123] The expander is the core link in the hydrogen refueling process. It mainly extracts expansion work from hydrogen through an approximately isentropic expansion process, reduces the enthalpy value of hydrogen, and recovers a large amount of energy. The expander not only effectively reduces the temperature of hydrogen but also can recover expansion work.

[0124] Multiple expanders are designed in parallel, and the controller 11 adjusts the expander to operate at the optimal speed according to the relationship between the inlet and outlet pressure ratio and the speed of the expander at the maximum efficiency, so that the full range of the pressure ratio can be fully utilized during the entire filling process, thereby efficiently recovering energy. The temperature of the hydrogen after precooling by the expander is reduced and enters the hydrogenation machine 10 for filling.

[0125] The temperature of the hydrogen gas after precooling by the expander is effectively controlled to avoid affecting the filling efficiency or threatening the safety of the hydrogen storage tank due to excessive temperature during the filling process. The hydrogen filling machine 10 injects hydrogen into the on-board hydrogen storage tank 12.

[0126] The energy recovered by the expander is converted into electrical energy by the connected generator. This electrical energy can be converted by a rectifier inverter, adjusted to power suitable for the grid frequency and connected to the grid for use by the city grid. Alternatively, the electrical energy can also be directly stored in an energy storage power station for subsequent use.

[0127] In this embodiment, the pressure of the high-pressure storage tank 1 is 90 MPa and the volume is 2.1 m 3 , providing 90MPa high-pressure hydrogen to the expansion unit; the expansion unit uses two expanders in parallel, both of which are radial flow turbine expanders. Usually one expander is suitable for higher pressure ratios and the other is suitable for lower pressure ratios, thereby ensuring that the expansion unit maintains efficient operation within a wider range of changing pressure ratios in the hydrogenation process. Its design parameters are listed in Table 1, and its structural parameters are listed in Table 2. The working range obtained by predicting the designed expander under non-design conditions is as follows:

[0128] The first expander 3 has a working pressure ratio range of 2.62-18, an outlet temperature of 200-220K, an isentropic efficiency of 50% to 80%, and an optimal speed range of 180000-230000 rev / min; the second expander 6 has a working pressure ratio range of 1.25-2.62, an outlet temperature of 240-280K, an isentropic efficiency of 50% to 75%, and an optimal speed range of 90000-176000 rev / min. The energy recovered by the expander can be converted into electrical energy through a generator, which can be used in a city power grid or stored in an energy storage power station. Figure 2 This is the predicted efficiency change curve of the expander with a design pressure ratio of 1.3 under non-design conditions; Figure 3 The predicted mass flow rate change curve of the expander with a design pressure ratio of 1.3 under non-design conditions; Figure 4 The predicted efficiency change curve of the expander with design pressure ratio 3 under non-design conditions; Figure 5 The predicted mass flow rate curve under off-design conditions for the expander with a design pressure ratio of 3. Figure 2 , Figure 4It can be seen that the rotational speed of the expander at maximum efficiency varies with the pressure ratio, obtaining the relationship between the pressure ratio and the optimal rotational speed at maximum efficiency. Therefore, the pressure ratio at the inlet and outlet of the expander is detected, and the rotational speed of the expander is adjusted according to its value to make it operate near the maximum efficiency. From Figure 2-5 It can be seen that the operating range parameters of different expanders are different. It is necessary to connect different expanders in parallel to form an expander unit to make it operate efficiently in the filling system.

[0129] Table 1 shows the design parameters of the two expanders used in Example 1

[0130] Design parameters First expander Second expander Pressure ratio (-) 3 1.3 Mass flow rate (g / s) 30.0 12.0 Inlet pressure (kPa) 88785 88571 Inlet temperature (K) 293.15 293.15 Rotational speed (rev / min) 200000 100000

[0131] Table 2 shows the structural parameters of the two expanders used in Example 1

[0132] Structure parameters First expander Second expander Nozzle radius (mm) 56.553 58.930 Impeller hub radius (mm) 28.258 29.465 Impeller tip radius (mm) 28.765 29.701 Number of impeller blades 21 23 Number of nozzle blades 18 18 Impeller inlet height (mm) 0.0147 0.0120 Axial clearance (mm) 4.424e-04 3.286e-04 Radial clearance (mm) 4.424e-04 3.286e-04 Outlet mean radius / inlet 0.500 0.500 Impeller height / diameter 1.304e-04 9.292e-05 Impeller tip / diameter 0.250 0.250

[0133] To further demonstrate the beneficial effects of this embodiment, Figure 1 a process simulation calculation is carried out, and the key operating parameters are as follows:

[0134] The ambient temperature is 293.15K; the pressure of high-pressure storage tank 1 is 90MPa; the initial pressure of the vehicle-mounted storage tank is 5MPa.

[0135] In this embodiment, in Scheme 3 using a parallel expander unit, the total recovered energy of the expander unit is 3067 kJ, and the final temperature of the vehicle-mounted storage tank is 63.95°C; while in Scheme 1 and Scheme 2 using a single expander, the recovered energies are 1923 kJ and 2377 kJ respectively, and the final temperatures of the vehicle-mounted storage tank are 84.33°C and 84.56°C respectively. Figure 6 is the curve of the actual operating efficiency of the expander related to the present invention changing with time; Figure 7 is the curve of the total output energy of the expander related to the present invention changing with time; Figure 8 is the curve of the temperature of the vehicle-mounted storage tank changing with time when the system related to the present invention fills the vehicle.

[0136] Through comparative analysis, this embodiment shows that Scheme 3 using a parallel expander unit can enable each expander to operate at a relatively high efficiency, significantly improving the working efficiency of the expander. Compared with the system using a single expander, the system using a parallel expander unit not only greatly improves the recovered energy, but also effectively reduces the final temperature of the vehicle-mounted storage tank, thereby improving the hydrogen filling efficiency and the safety of the hydrogen storage tank.

[0137] In summary, the present invention provides a low-energy consumption and high-efficiency gaseous hydrogen filling system based on the parallel regulation of multiple expanders. Compared with the existing filling technologies, the present invention has the following significant advantages:

[0138] The present invention uses an expansion unit to replace the pre-cooling system in the traditional hydrogen refueling station model. The expansion unit can not only effectively pre-cool hydrogen, but also recover a large amount of energy during this process, thus significantly improving the energy efficiency of the system.

[0139] Compared with the existing refueling system using a single expander, the present invention designs a parallel expansion unit, and by controlling the expander to operate at the optimal rotational speed corresponding to the maximum efficiency, each expander can operate efficiently within a wider pressure ratio range, thereby recovering more energy and ensuring that the system always operates at a high efficiency throughout the refueling process.

[0140] The present invention can better control the temperature of the on-vehicle hydrogen storage tank 12, ensuring that its temperature is always maintained within 85°C, avoiding the reduction of refueling efficiency or potential safety hazards of the hydrogen storage tank caused by excessive temperature.

[0141] The above further describes the technical solutions provided by the present invention in several specific embodiments to highlight the advantages and beneficial effects of the technical solutions provided by the present invention. However, the above several specific embodiments are not used as limitations on the present invention. Any reasonable modifications and improvements, combinations of embodiments, and equivalent substitutions based on the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A low-energy consumption and high-efficiency gas-hydrogen filling method based on parallel control of multiple expanders, characterized in that: The method is implemented based on a low-energy consumption and high-efficiency gas-hydrogen filling system based on parallel control of multiple expanders. The low-energy consumption and high-efficiency gas-hydrogen filling system includes: High-pressure storage tanks, used to store high-pressure hydrogen; An expansion unit, comprising at least two expanders arranged in parallel, each expander having a different working pressure ratio range, and an inlet of the expansion unit is connected to the high-pressure storage tank through a pipeline; A controller is used to monitor the pressure ratio between the inlet and outlet of the expander in real time, dynamically select the corresponding expander to work according to the pressure ratio, and adjust the speed of the selected expander to the speed range corresponding to its maximum efficiency; A hydrogen filling machine, connected to the outlet of the expansion unit, for filling the hydrogen precooled by the expansion unit into the on-board hydrogen storage tank; a generator, connected to each of the expanders, for converting the mechanical energy recovered by the expanders into electrical energy; Methods include: The step of monitoring the inlet and outlet pressure ratio of the expansion unit in real time and obtaining current pressure ratio data; The step of determining the optimal expander and the corresponding optimal speed range under the current pressure ratio according to a preset pressure ratio-speed efficiency curve; Dynamically switch to the optimal expander and adjust its speed to the optimal speed range so that the expander operates at maximum efficiency; Real-time monitoring of the hydrogen temperature at the outlet of the expander unit, and when it is detected that the temperature exceeds a preset threshold, triggering the step of adjusting the expander speed or switching the expander; The step of converting the mechanical energy recovered by the expander into electrical energy through a generator, and storing or integrating the electrical energy into a power grid; According to the real-time pressure and temperature data of the on-board hydrogen storage tank, the filling rate of the hydrogen filling machine is adjusted to ensure that the hydrogen temperature does not exceed 85°C during the filling process.

2. A low-energy-consumption and high-efficiency gas-hydrogen filling method based on parallel control of multiple expanders according to claim 1, characterized in that: A control valve and a pressure measuring gauge are provided on the pipeline connecting the inlet of the expansion unit and the high-pressure storage tank.

3. The low energy consumption and high efficiency gas hydrogen filling method based on parallel control of multiple expanders according to claim 1 is characterized in that: The high-pressure storage tank includes a high-pressure hydrogen storage tank with a pressure of 90 MPa and a volume of 2.1 m³.

4. A low-energy-consumption and high-efficiency gas-hydrogen filling method based on parallel control of multiple expanders according to claim 1, characterized in that: The expander in the expander group is a radial flow turbine expander, including a first expander and a second expander. The first expander has an operating pressure ratio range of 2.62-18, an isentropic efficiency of 50%-80%, and an optimal speed range of 180000-230000 rev / min; The operating pressure ratio range of the second expander is 1.25-2.62, the isentropic efficiency is 50%-75%, and the optimal speed range is 90000-176000 rev / min.

5. The low-energy-consumption and high-efficiency gas-hydrogen filling method based on parallel control of multiple expanders according to claim 1 is characterized in that: The generator is connected to the outlet of the expansion unit through a coupling, and the electric energy output by the generator is converted into grid-compatible alternating current through a rectifier inverter, or stored in an energy storage power station.

6. A low-energy-consumption and high-efficiency gas-hydrogen filling method based on parallel control of multiple expanders according to claim 1, characterized in that: The system also includes a temperature control module, which dynamically adjusts the temperature of the hydrogen at the expander outlet to not exceed 85°C through the controller.

7. A computer storage medium for storing a computer program, characterized in that: When the computer program is read by a computer, the computer executes the method of claim 1 .

8. A computer, comprising a processor and a storage medium, characterized in that: When the processor reads the computer program stored in the storage medium, the computer executes the method of claim 1 .

9. A computer program product, being a computer program, characterized in that When the computer program is executed, the method of claim 1 is implemented.

Images