Low-energy-consumption high-efficiency gas hydrogen filling system based on parallel regulation and control of multiple expansion machines

Abstract

The invention discloses a low-energy-consumption efficient gas hydrogen filling system based on multi-expansion-machine parallel control. Relates to the technical field of hydrogen energy, solves the problems of low efficiency of a single expansion machine, insufficient adaptability of a series expansion unit and unsatisfactory temperature control in the prior art, remarkably reduces the hydrogenation energy consumption, and improves the hydrogenation efficiency and safety. Comprising a high-pressure storage tank, an expansion unit, a controller, a hydrogenation machine and a generator. The expansion unit is composed of at least two expansion machines which are arranged in parallel, and each expansion machine has different working pressure ratio ranges and is suitable for hydrogenation working conditions with wide pressure ratio changes. The controller monitors the pressure ratio of the inlet to the outlet of the expansion machine in real time, dynamically selects the optimal expansion machine and adjusts the rotating speed of the optimal expansion machine to the rotating speed range corresponding to the maximum efficiency, and it is ensured that the system efficiently operates within the wide pressure ratio range. Precooled hydrogen is filled into the vehicle-mounted hydrogen storage tank by the hydrogen adding machine, and the mechanical energy recovered by the expansion machine is converted into electric energy by the generator. The method is suitable for hydrogen refueling stations of 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, 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;

[0022] 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;

[0023] 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;

[0024] The generator is connected to each of the expanders respectively and is used for converting the mechanical energy recovered by the expander into electrical energy.

[0025] Furthermore, a preferred embodiment is provided, in which 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.

[0026] Further, a preferred embodiment is provided, wherein the high-pressure storage tank comprises a high-pressure hydrogen storage tank with a pressure of 90 MPa and a volume of 2.1 m 3 .

[0027] Further, a preferred embodiment is provided, wherein the expander in the expander group is a radial flow turbine expander, including a first expander and a second expander,

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

[0029] The working 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.

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

[0031] Furthermore, a preferred embodiment is provided, wherein the system further comprises a temperature control module, and the temperature of the hydrogen at the outlet of the expander is dynamically adjusted by the controller to be no more than 85°C.

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

[0033] The step of monitoring the inlet and outlet pressure ratio of the expansion unit in real time and obtaining current pressure ratio data;

[0034] 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;

[0035] Dynamically switch to the optimal expander and adjust its speed to the optimal speed range so that the expander operates at maximum efficiency;

[0036] 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;

[0037] 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;

[0038] 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.

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

[0040] Based on the same inventive concept, the present invention also 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 a method.

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

[0042] Compared with the prior art, the technical solution provided by the present invention is beneficial in that:

[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 ratios of the expander will continue to change as the hydrogenation proceeds, and it is difficult for a single expander to maintain efficient operation within the entire pressure ratio range. The present invention uses multiple parallel expanders, each of which is optimized for different pressure ratio ranges, to ensure that the optimal expander can operate 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 entire filling process, avoiding the problem of decreased efficiency of a single expander under non-design conditions. Compared with the solution of a single expander in existing research, the present invention significantly improves the operating efficiency of the system within a wide pressure ratio range.

[0044] The speed of the expander is adjusted in real time by the controller to ensure that each expander works at 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 speed of the expander in real time according to the relationship between the pressure ratio and the speed at maximum efficiency, so that it always works within the optimal speed range. For example, the optimal speed range of the first expander is 180000-230000rev / min, and the optimal speed range of the second expander is 90000-176000rev / 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 scheme of a single expander in existing studies, the energy recovery efficiency of the present invention is significantly improved, and the total energy recovered by the system is increased from 1923kJ (single expander scheme 1) and 2377kJ (single expander scheme 2) to 3067kJ (parallel expander group scheme 3).

[0045] The design of the parallel expansion unit effectively controls the temperature of the on-board hydrogen storage tank and ensures the safety of the hydrogenation process. During the hydrogenation process, the temperature control of hydrogen is crucial. Excessive temperature may cause the material of the on-board hydrogen storage tank to fail or cause safety hazards. The present invention pre-cools the hydrogen through multiple parallel expansion units to ensure that the temperature of the hydrogen is always within a safe range during the filling process. For example, in the embodiment, using Scheme 3 of the parallel expansion unit, the final temperature of the on-board hydrogen storage tank is 63.95°C, while the final temperatures of Schemes 1 and 2 of the single expansion unit are 84.33°C and 84.56°C, respectively. Compared with existing studies, the present invention significantly reduces the final temperature of the on-board hydrogen storage tank through the design of the parallel expansion unit, thereby 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. The expander in the present invention is not only used to cool hydrogen, but also to recover expansion work through an isentropic expansion process, and convert the recovered energy into electrical energy through a 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 an embodiment, the total energy recovered by the expander group is 3067kJ, which is significantly higher than the 1923kJ and 2377kJ of a single expander solution. Compared with the solutions that rely only on precooling systems in existing studies, the present invention further reduces the energy consumption of the system and improves the overall energy efficiency through an energy recovery mechanism.

[0047] In summary, the present invention significantly improves the operating efficiency, energy recovery capability and safety of the hydrogenation system through dynamic switching of multiple parallel expanders, real-time speed adjustment of the controller, temperature control optimization and 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 group in the prior art under a wide pressure ratio range.

[0048] It is suitable for low-energy and high-efficiency gas-hydrogen filling with parallel control of multiple expanders. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the structure of the parallel expander hydrogenation system provided by the present invention;

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

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

[0052] Figure 4 The predicted efficiency change curve of the expander with design pressure ratio 3 under non-design conditions;

[0053] Figure 5 The predicted mass flow rate variation curve of the expander with design pressure ratio 3 under non-design conditions;

[0054] Figure 6 The actual operating efficiency of the expander according to the present invention changes with time;

[0055] Figure 7 The total energy output of the expander according to the present invention changes with time;

[0056] Figure 8 This is a curve showing the temperature of the vehicle tank changing with time when the system of the present invention is refueling the vehicle.

[0057] Among them, 1. high-pressure storage tank; 2. first control valve; 3. first expansion machine; 4. first generator; 5. second control valve; 6. second expansion machine; 7. second generator; 8. first pressure measuring gauge; 9. first temperature measuring gauge; 10. hydrogen filling machine; 11. controller; 12. on-board hydrogen storage tank; 13. second pressure measuring gauge; 14. third pressure measuring gauge. DETAILED DESCRIPTION

[0058] In order to make the advantages and benefits of the technical solution provided by the present invention more clearly reflected, the technical solution provided by the present invention is now further described in detail with reference to the accompanying drawings, specifically:

[0059] Embodiment 1: This embodiment provides a low-energy consumption and high-efficiency gas-hydrogen filling system based on parallel control of multiple expanders, including:

[0060] High-pressure storage tank 1, used for storing high-pressure hydrogen;

[0061] 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 1 through a pipeline;

[0062] The controller 11 is used to monitor the pressure ratio between the inlet and outlet of the expander in real time, and 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;

[0063] A hydrogen filling machine 10, connected to the outlet of the expansion unit, for filling the hydrogen precooled by the expansion unit into the on-board hydrogen storage tank 12;

[0064] The generator is connected to each of the expanders respectively and is used for converting the mechanical energy recovered by the expander into electrical energy.

[0065] Embodiment 2. This embodiment is a further limitation of the low-energy consumption and high-efficiency gas-hydrogen filling system based on parallel control of multiple expanders provided in Embodiment 1. 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 1.

[0066] Embodiment 3: This embodiment is a further limitation of a low-energy consumption and high-efficiency gas hydrogen filling system based on parallel control 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 defines a low-energy consumption and high-efficiency gas-hydrogen filling system based on parallel control of multiple expanders provided in embodiment 1. The expander in the expander group is a radial flow turbine expander, including a first expander 3 and a second expander 6.

[0068] The working pressure ratio range of the first expander 3 is 2.62-18, the isentropic efficiency is 50%-80%, and the optimal speed range is 180000-230000 rev / min;

[0069] The working pressure ratio range of the second expander 6 is 1.25-2.62, the isentropic efficiency is 50%-75%, and the optimal rotation speed range is 90000-176000 rev / min.

[0070] Implementation method five. This implementation method is a further limitation of the low-energy consumption and high-efficiency gas-hydrogen filling system based on parallel control of multiple expanders provided in implementation method one. 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 AC power through a rectifier inverter, or stored in an energy storage power station.

[0071] Embodiment 6. This embodiment is a further limitation of the low-energy consumption and high-efficiency gas-hydrogen filling system based on parallel control of multiple expanders provided in embodiment 1. 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 11.

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

[0073] The step of monitoring the inlet and outlet pressure ratio of the expansion unit in real time and obtaining current pressure ratio data;

[0074] 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;

[0075] Dynamically switch to the optimal expander and adjust its speed to the optimal speed range so that the expander operates at maximum efficiency;

[0076] 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;

[0077] 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;

[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-board hydrogen storage tank 12 to ensure that the hydrogen temperature does not exceed 85° C. during the filling process.

[0079] Specific:

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

[0081] Pressure ratio monitoring device: high-precision pressure sensors (such as the second pressure measuring gauge 13, the third pressure measuring gauge 14 and the first pressure measuring gauge 8) are respectively installed 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 10 times per second and calculates the current pressure ratio. The data is filtered and stored in the local database for subsequent analysis and control decisions.

[0083] Abnormal handling: If a pressure fluctuation exceeding ±5% (such as pipeline blockage or leakage) is detected, the controller will immediately trigger an alarm and suspend the filling process.

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

[0085] Step 2: According to the preset pressure ratio-speed efficiency curve, determine the optimal expander and its corresponding optimal speed range under the current pressure ratio

[0086] Pressure ratio-speed efficiency curve modeling: Based on experimental data and simulation analysis, the efficiency-pressure ratio-speed three-dimensional relationship curve of each expander is pre-established. For example, the speed corresponding to the efficiency peak of the first expander 3 at a pressure ratio of 2.62-18 is 180000-230000 rev / min, and the speed corresponding to the efficiency peak of the second expander 6 at a pressure ratio of 1.25-2.62 is 90000-176000 rev / min (e.g. 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 is ≥2.62, the first expander 3 is selected, and when the pressure ratio is <2.62, the second expander 6 is switched.

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

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

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

[0091] Switching control logic: The controller 11 sends a command to the corresponding control valve to close the inlet valve of the non-working expander and open the inlet valve of the target expander. The switching process is completed within 200ms to avoid sudden pressure changes.

[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, it triggers re-matching of the pressure ratio-speed curve or switching of the expander.

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

[0095] Step 4: Real-time monitoring of the hydrogen temperature at the outlet of the expander unit. When the temperature exceeds the preset threshold, the expander speed is adjusted or the expander is switched.

[0096] Temperature monitoring device: A platinum resistance temperature sensor (first temperature measuring meter 9) is installed on the outlet pipeline of the expansion unit to collect the hydrogen temperature in real time with an accuracy of ±0.5K.

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

[0098] Primary response: Increase the current expander speed to a higher speed segment of the efficiency curve (such as increasing the first expander from 200,000 rev / min to 220,000 rev / min) to enhance the refrigeration effect.

[0099] Secondary response: If the temperature is still above the limit after the primary response, immediately switch to another expander and re-match the speed.

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

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

[0102] Step 5: The mechanical energy recovered by the expander is converted into electrical energy through a generator, and the electrical energy is stored or incorporated into the 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 10: This embodiment provides a computer program product, which is a computer program. When the computer program is executed, the method provided in embodiment 7 is implemented.

[0118] Implementation Method XI: Combination Figure 1-8 This embodiment is described in detail by using specific examples to further describe the technical solution provided above. Specifically:

[0119] Example 1

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

[0121] The following is an explanation of the use principle of the low energy consumption and high efficiency gas hydrogen filling system based on parallel control of multiple expanders:

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

[0123] The expander is the core link in the hydrogenation process. It mainly extracts expansion work from hydrogen through a nearly isentropic expansion process, reduces the enthalpy of hydrogen, and recovers a large amount of energy. The expander not only effectively reduces the temperature of hydrogen, but also recovers 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 speed of the expander at maximum efficiency changes with the pressure ratio, and the relationship between the pressure ratio and the optimal speed at maximum efficiency is obtained. Therefore, the inlet and outlet pressure ratio of the expander is tested, and the speed of the expander is adjusted according to its value to make it work near the maximum efficiency. Figure 2-5 It can be seen that the working range parameters of different expanders are different, and it is necessary to connect different expanders in parallel to form an expander group 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 shoulder 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 Speed ​​(rev / min) 200000 100000

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

[0132] Structural parameters First expander Second expander Nozzle radius (mm) 56.553 58.930 Impeller hub radius (mm) 28.258 29.465 Impeller rim radius (mm) 28.765 29.701 Impeller blade number 21 23 Nozzle blade number 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 Average radius of outlet / inlet 0.500 0.500 Impeller height / diameter 1.304e-04 9.292e-05 Impeller rim / diameter 0.250 0.250

[0133] In order to further demonstrate the beneficial effects of this embodiment, Figure 1 Carry out process simulation calculation, 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 on-board storage tank is 5MPa.

[0135] In this embodiment, in Scheme 3 using parallel expansion units, the total energy recovered by the expansion units is 3067 kJ, and the final temperature of the on-board storage tank is 63.95°C; while in Schemes 1 and 2 using a single expansion unit, the recovered energy is 1923 kJ and 2377 kJ respectively, and the final temperature of the on-board storage tank is 84.33°C and 84.56°C respectively. Figure 6 The actual operating efficiency of the expander according to the present invention changes with time; Figure 7 The total energy output of the expander according to the present invention changes with time; Figure 8 This is a curve showing the temperature of the vehicle tank changing with time when the system of the present invention is refueling the vehicle.

[0136] Through comparative analysis, this embodiment shows that the scheme 3 using parallel expansion units can achieve high efficiency operation of each expander, significantly improving the working efficiency of the expander. Compared with the single expander system, the parallel expansion unit system not only greatly increases the recovered energy, but also effectively reduces the final temperature of the on-board storage tank, thereby improving the hydrogenation efficiency and the safety of the hydrogen storage tank.

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

[0138] The present invention adopts an expansion unit to replace the precooling system in the traditional hydrogen refueling station model. The expansion unit can not only effectively precool the hydrogen, but also recover a large amount of energy in the process, thereby significantly improving the energy efficiency of the system.

[0139] Compared with the existing filling system using a single expander, the present invention adopts the design of parallel expansion units and controls the expanders to operate at the optimal speed corresponding to the maximum efficiency, so that each expander can operate efficiently within a wider pressure ratio range, thereby recovering more energy and ensuring that the system is always at a high operating efficiency during the entire filling process.

[0140] The present invention can better control the temperature of the on-board hydrogen storage tank 12, ensuring that the temperature is always maintained below 85°C, thereby avoiding reduced filling efficiency or potential safety hazards of the hydrogen storage tank due to excessively high temperature.

[0141] The technical solution provided by the present invention is further described in detail above through several specific implementation modes in order to highlight the advantages and benefits of the technical solution provided by the present invention. However, the several specific implementation modes described above are not intended to be used as limitations on the present invention. Any reasonable modification and improvement of the present invention, combination of implementation modes and equivalent substitution within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low energy consumption and high efficiency gas hydrogen filling system based on parallel control of multiple expanders, characterized in that: include: 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; The generator is connected to each of the expanders respectively and is used for converting the mechanical energy recovered by the expander into electrical energy.

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

4. A low energy consumption and high efficiency gas hydrogen filling system 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 working 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 system 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. The low energy consumption and high efficiency gas hydrogen filling system based on parallel control of multiple expanders according to claim 1 is 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 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 the system of claim 1, comprising: 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.

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

9. 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 7 .

10. A computer program product, being a computer program, characterized in that When the computer program is executed, the method of claim 7 is implemented.

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