A distributed hydrogenation booster system based on hydraulic displacement and its control method

Abstract

This invention discloses a distributed hydrogen refueling and pressurization system based on hydraulic displacement and its control method. The system includes at least two high-pressure storage tanks, a hydrogen circuit, and a hydraulic circuit. The hydrogen circuit includes a low-pressure hydrogen circuit and a high-pressure hydrogen circuit. The low-pressure hydrogen inlet is connected to the high-pressure storage tank via the low-pressure hydrogen circuit, and the high-pressure storage tank is connected to the high-pressure hydrogen outlet via the high-pressure hydrogen circuit. The number of low-pressure hydrogen circuits is the same as the number of high-pressure storage tanks, and the number of high-pressure hydrogen circuits is the same as the number of high-pressure storage tanks. The hydraulic circuit includes a liquid storage tank and a pump. The liquid storage tank is sequentially connected to the pump and the liquid phase inlet of the high-pressure storage tank. The outlet of the high-pressure storage tank is connected to the liquid storage tank via pipelines, forming a hydraulic circuit. This invention's system features high safety and high stability.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen storage and hydrogen refueling equipment manufacturing, specifically relating to a distributed hydrogen refueling booster system based on hydraulic displacement and its control method. Background Technology

[0002] Hydrogen energy is an important component of clean energy, and its storage, transportation, and refueling are key links in the industrial chain. At hydrogen refueling stations, the produced hydrogen (at a pressure of about 3~5MPa) typically needs to be pressurized to a high pressure of 35MPa or 70MPa to meet the refueling requirements of fuel cell vehicles.

[0003] Currently, there are two main types of hydrogen refueling booster equipment: diaphragm compressors and screw compressors.

[0004] Diaphragm compressors utilize hydraulic oil to drive a metal diaphragm in reciprocating motion. The diaphragm separates the hydraulic oil from the hydrogen gas, thus compressing the hydrogen. Its advantages include a pollution-free compression process and good sealing. However, its disadvantages are equally apparent: the metal diaphragm is prone to fatigue failure under high-pressure alternating loads, resulting in a limited lifespan and requiring periodic replacement; furthermore, the diaphragm's deformation limits the single-stage compression ratio, often necessitating multi-stage series operation; additionally, the hydraulic system itself suffers from dynamic sealing issues.

[0005] Screw compressors compress hydrogen gas through the rotation of a pair of meshing screw rotors. Their advantages include compact structure and high flow rate. However, screw compressors have the following problems: lubricating oil is required for sealing and cooling between the rotors and between the rotor and the housing, posing a risk of lubricating oil contamination of the hydrogen; dynamic seals such as shaft seals are subjected to high-pressure alternating loads for extended periods, making them prone to leakage; and the gas temperature rises significantly during compression, requiring a complex cooling system.

[0006] Hydraulic displacement pressurization is a technology that has gained attention in recent years. Its basic principle is to utilize the incompressibility of liquids by injecting them into a sealed container, compressing the hydrogen gas within the container at constant pressure, thereby achieving pressurization. Existing related technologies employ a high-pressure storage tank, a liquid storage tank, a hydraulic pump, and corresponding valves and pipelines. During operation, low-pressure hydrogen gas is first introduced into the storage tank, then the hydraulic pump injects liquid into the tank, compressing the hydrogen to high pressure before outputting it. Subsequently, the liquid is discharged, and low-pressure hydrogen gas is refilled, initiating the next cycle. Although this type of solution avoids the dynamic sealing problem of traditional compressors, it still has the following shortcomings: (1) Insufficient sealing reliability: The dynamic sealing structure of traditional compressors is the main risk point of hydrogen leakage, and the reliability of long-term operation decreases; (2) Low energy efficiency: The mechanical loss and heat loss during the compression process are large, and the pressure energy during liquid discharge is not recovered and utilized; (3) Discontinuous output: The single tank system cannot supply gas during the liquid discharge and gas replenishment stage, which affects the continuity of filling; (4) Large switching impact: The rapid switching of valves in the dual tank system generates water hammer effect, causing pipeline vibration and equipment fatigue; (5) Insufficient control accuracy: The means of monitoring and controlling the gas-liquid interface are limited, and filling mismatch is easy to occur; (6) High maintenance cost: The diaphragm, screw and other vulnerable parts need to be replaced regularly, and the maintenance cycle is short. Summary of the Invention

[0007] This invention addresses the shortcomings of existing hydropressurization technologies, including high leakage risk, low energy utilization, high maintenance costs, water hammer effect causing impact vibration during valve switching in alternating operation of dual tanks, and susceptibility to misalignment during gas-liquid filling. It provides a distributed hydropressurization system based on hydraulic displacement and its control method. Through a fully static sealed structure, alternating operation of multiple tanks, soft switching via a throttling bypass valve, hydraulic-electric coupling energy recovery, and multi-parameter fusion control using redundant sensors, it achieves safe, reliable, highly efficient, energy-saving, continuous, stable, and vibration-free hydropressurization.

[0008] The objective of this invention is achieved by at least one of the following technical solutions.

[0009] A distributed hydrogen refueling and boosting system based on hydraulic displacement includes at least two high-pressure storage tanks, a hydrogen circuit, and a hydraulic circuit;

[0010] The hydrogen circuit includes a low-pressure hydrogen circuit and a high-pressure hydrogen circuit. The low-pressure hydrogen inlet is connected to the high-pressure storage tank through the low-pressure hydrogen circuit, and the high-pressure storage tank is connected to the high-pressure hydrogen outlet through the high-pressure hydrogen circuit. The number of low-pressure hydrogen circuits is the same as the number of high-pressure storage tanks, and the number of high-pressure hydrogen circuits is the same as the number of high-pressure storage tanks.

[0011] The hydraulic circuit includes a storage tank and a pump; the storage tank is sequentially connected to the pump and the liquid phase inlet of the high-pressure storage tank; the outlet of the high-pressure storage tank is connected to the storage tank through pipes to form a hydraulic circuit.

[0012] More preferably, the pump is one or more of a hydraulic pump, a variable frequency drive pump, a variable displacement pump, a fixed displacement pump, and a proportional relief valve combined with a proportional relief valve; the variable frequency drive pump adjusts the flow rate by changing the motor speed; the variable displacement pump changes the displacement by adjusting the swashplate angle; the fixed displacement pump combined with the proportional relief valve is a fixed displacement pump with a proportional relief valve, and the device achieves flow control through bypass adjustment.

[0013] More preferably, the pump is driven by an external power source or an energy storage power source.

[0014] More preferably, the energy storage power drive device includes a generator, a rectifier, an energy storage battery, and an inverter; the generator is connected in sequence to the rectifier, the energy storage battery, the inverter, and the pump.

[0015] More preferably, each high-pressure storage tank is equipped with a shut-off valve on its outlet pipe; a throttling bypass valve is connected in parallel to the shut-off valve.

[0016] More preferably, the turbine of the generator is installed at a height not higher than the liquid phase interface of the high-pressure storage tank (to facilitate liquid reflux).

[0017] More preferably, a buffer tank and a proportional flow valve are provided between the pump and the liquid phase inlet of the high-pressure storage tank. The outlet of the proportional flow valve is divided into several branches, the number of which is the same as the number of high-pressure storage tanks. A check valve and a shut-off valve are provided on each branch, and a throttling bypass valve is connected in parallel to the shut-off valve.

[0018] More preferably, the buffer tank is replaced by an airbag accumulator, a piston accumulator, or a spring accumulator.

[0019] More preferably, the top of the liquid storage tank is provided with a nitrogen filling port for filling the space above the liquid surface with nitrogen to form an inert gas protective layer, maintain the positive pressure of the liquid storage tank, and prevent pump cavitation; the liquid storage tank is connected to the nitrogen filling chamber.

[0020] More preferably, each low-pressure hydrogen circuit is equipped with a check valve and a shut-off valve; each high-pressure hydrogen circuit is equipped with a check valve and a shut-off valve.

[0021] More preferably, the high-pressure hydrogen circuit is also equipped with a hydrogen purification and cooling device.

[0022] More preferably, the bottom of the high-pressure storage tank is also provided with a gas phase interface, which is connected to a pressure relief port through a pipeline, and a safety valve is also provided on the pipeline.

[0023] More preferably, the number of high-pressure storage tanks is 2-5.

[0024] More preferably, the liquid outlet and the liquid phase inlet are located at the bottom of the high-pressure storage tank.

[0025] More preferably, the present invention further includes sensors, including a pressure sensor, a liquid level sensor, and a flow sensor; the pressure sensor is disposed at the following locations: at the gas phase interface of the high-pressure storage tank, at the liquid phase interface of the high-pressure storage tank, on the outlet pipeline of the pump, and at the outlet of the buffer tank; the liquid level sensor is disposed inside the high-pressure storage tank, with two independent liquid level sensors disposed in each tank; the flow sensor is disposed on the main pipeline between the outlet of the proportional flow valve and the check valve.

[0026] A distributed hydrogen pressurization control method based on hydraulic displacement using the aforementioned system first pre-charges all high-pressure storage tanks with low-pressure hydrogen to ensure that the pressure in all high-pressure storage tanks reaches the preset initial pressure; then injects liquid into the first high-pressure storage tank to perform pressurization and hydrogen supply operation; then performs a first switch to put the system into a preparatory state for alternating cycles, and then performs standard alternating cycles of all high-pressure storage tanks; the alternating cycle includes pressurizing the first high-pressure storage tank and draining liquid from a non-first high-pressure storage tank, or pressurizing a non-first high-pressure storage tank and draining liquid from the first high-pressure storage tank.

[0027] In the above method, the step of injecting liquid into the first high-pressure storage tank to pressurize and supply hydrogen is as follows: open the valve at the liquid inlet of the first high-pressure storage tank, start the pump to inject liquid into the first high-pressure storage tank, and then open the valve on the high-pressure hydrogen circuit of the first high-pressure storage tank. The pump dynamically adjusts the flow rate according to the pressure change rate, so that the hydrogen in the first high-pressure storage tank is stably compressed to the target pressure P_. target High-pressure hydrogen is output through the high-pressure hydrogen outlet after passing through the high-pressure circuit. At this time, non-first high-pressure storage tanks are in an isolated state. When the pressure in the first high-pressure storage tank reaches the target pressure P... _target And the injection volume reaches V _max = α × V _tank_eff When this happens, first close the valve at the liquid inlet, then close the valve on the high-pressure circuit to stop the pump from operating;

[0028] The α is the injection ratio, ranging from 0.95 to 0.98; the V _tank_eff This refers to the effective volume of the high-pressure storage tank.

[0029] In the above method, the first switching operation is as follows: first, balance the pressure in all high-pressure storage tanks so that the pressures are close; continuously inject liquid to pressurize the non-first high-pressure storage tank, while the liquid in the first high-pressure storage tank continuously flows back to the storage tank; when the pressure in the first high-pressure storage tank drops to a set threshold, inject low-pressure hydrogen to completely discharge the remaining liquid; when the pressure in one of the non-first high-pressure storage tanks reaches a predetermined threshold, stop injecting liquid into the non-first high-pressure storage tank and discharging high-pressure hydrogen, while stop discharging liquid and inputting low-pressure hydrogen into the first high-pressure storage tank, so that the system enters the preparatory state of alternating cycle; the preparatory state of alternating cycle is that the first high-pressure storage tank has been emptied and filled with low-pressure hydrogen, and the non-first high-pressure storage tank is filled with high-pressure liquid.

[0030] In the above method, the specific operation of the first switching is as follows: open the liquid inlet valve of a selected non-first high-pressure storage tank, start the pump, inject liquid into the non-first high-pressure storage tank, and simultaneously open the outlet valve of the first high-pressure storage tank to allow high-pressure liquid to flow into the storage tank. When the liquid pressure difference between the two high-pressure storage tanks is less than a preset threshold, open the liquid inlet valve of the non-first high-pressure storage tank and the outlet valve of the first high-pressure storage tank to inject liquid and increase pressure into the non-first high-pressure storage tank. When the pressure in the first high-pressure storage tank drops to P1, open all valves on the low-pressure hydrogen circuit of the first high-pressure storage tank, allowing low-pressure hydrogen to enter the first high-pressure storage tank and completely discharge the residual liquid. When the pressure in the non-first high-pressure storage tank reaches P... _target And the injection volume reaches V _max When switching is complete, first close the valve at the liquid inlet of the non-first high-pressure storage tank, then close the valve at the high-pressure hydrogen circuit of the non-first high-pressure storage tank, stop the pump operation, and then close the valve at the liquid outlet of the first high-pressure storage tank and the valve at the low-pressure hydrogen circuit of the first high-pressure storage tank.

[0031] In the above method, the non-first high-pressure storage tank is in an isolated state by: closing the shut-off valves on the low-pressure hydrogen circuit and the high-pressure hydrogen circuit of the non-first high-pressure storage tank, closing the shut-off valves and throttling bypass valves on the liquid inlet and outlet of the other high-pressure storage tanks, and closing the shut-off valve on the low-pressure hydrogen circuit of the high-pressure storage tank.

[0032] In the above method, before the pressurization and hydrogen supply step of the high-pressure storage tank during the first system startup, an initial state setting operation is required. The purpose is to pre-inject a certain volume of liquid into one of the high-pressure storage tanks (the first tank) so that it can normally compress hydrogen and supply hydrogen to the outside during the first pressurization cycle. At the same time, the other storage tanks remain empty of liquid and filled with low-pressure hydrogen to establish initial conditions for subsequent alternating cycles. The initial state setting operation can be as follows: one high-pressure storage tank is injected with liquid while the other high-pressure storage tanks are on standby, or each high-pressure storage tank is partially injected with liquid, and then the pressurization and liquid discharge cycle is entered sequentially.

[0033] When there are two high-pressure storage tanks in this invention, a distributed hydrogenation pressurization control method based on hydraulic displacement using the system includes the following steps:

[0034] S101: System initialization: All shut-off valves are reset to the closed state, all throttling bypass valves are reset to the closed state, the controller performs a self-test, and checks the status of each sensor;

[0035] S102: Low-pressure pre-charge: Open the shut-off valve on the low-pressure hydrogen circuit of the first high-pressure storage tank and the shut-off valve on the low-pressure hydrogen circuit of the second high-pressure storage tank. Hydrogen enters the first and second high-pressure storage tanks from the low-pressure hydrogen inlet. Monitor the pressure of both tanks until they both reach the preset initial pressure P0. Then close the shut-off valve on the low-pressure hydrogen circuit of the first and second high-pressure storage tanks. The preset initial pressure P0 is 3~5MPa.

[0036] S103: Pressure Confirmation: Confirm that the pressure of both the first high-pressure storage tank and the second high-pressure storage tank has reached the preset start threshold P1, where P1 = P0; if not, alarm and return to S102.

[0037] S103.5: Initial state settings:

[0038] (1) Open the throttling bypass valve of the shut-off valve at the liquid inlet of the first high-pressure storage tank, start the pump to slowly inject liquid into the first high-pressure storage tank at a low flow rate, and monitor the change of gas phase pressure in the first high-pressure storage tank at the same time; the low flow rate is 1~5 L / min, preferably 2 L / min;

[0039] (2) When the pressure inside the first high-pressure storage tank rises steadily and there are no abnormal fluctuations, open the shut-off valve at the liquid phase inlet of the first high-pressure storage tank and close the throttling bypass valve.

[0040] (3) The pump dynamically adjusts the flow rate based on pressure feedback and continues to inject liquid to a volume V0; the setting of V0 must meet the following condition: after injection, the hydrogen pressure P2 in the first high-pressure storage tank is not higher than the target pressure P. _target 60% to 80% of the volume, and the remaining gas phase space is not less than 10% of the effective volume;

[0041] (4) After reaching V0, first close the shut-off valve at the liquid inlet of the first high-pressure tank and the pump stops working; at this time the system status is: the first high-pressure tank has liquid and the internal pressure is P2; the second high-pressure tank has no liquid and the internal pressure is P1.

[0042] S104: First boost cycle

[0043] (1) Open the throttling bypass valve of the shut-off valve at the liquid phase inlet of the first high-pressure storage tank, start the pump to inject liquid into the first high-pressure storage tank at a low flow rate, and when the pressure difference across the shut-off valve is less than the preset threshold, open the shut-off valve at the liquid phase inlet of the first high-pressure storage tank and close the throttling bypass valve; the preset threshold is 0.2~0.5MPa, preferably 0.3MPa;

[0044] (2) Open the shut-off valve at the high-pressure hydrogen circuit of the first high-pressure storage tank. The pump dynamically adjusts the flow rate according to the pressure change rate (pressure rise rate ≤ 1MPa / s) to smoothly compress the hydrogen in the first high-pressure storage tank to the target pressure P. _target ;

[0045] (3) The high-pressure hydrogen in the first high-pressure storage tank is output from the high-pressure hydrogen outlet after passing through the hydrogen purification and cooling device;

[0046] (4) The second high-pressure storage tank is kept in an isolated state; the isolated state is as follows: the shut-off valve and the throttling bypass valve at the liquid inlet of the second high-pressure storage tank are closed, the shut-off valves on the high-pressure hydrogen circuit and the low-pressure hydrogen circuit of the second high-pressure storage tank, the shut-off valve and the throttling bypass valve at the liquid outlet of the second high-pressure storage tank are closed, and the shut-off valve on the low-pressure hydrogen circuit of the first high-pressure storage tank is closed.

[0047] (5) When the pressure of the first high-pressure storage tank reaches the target pressure P _target And the injection volume reaches V _max = α ×V _tank_eff When the pump stops, first close the shut-off valve at the liquid inlet of the first high-pressure storage tank, then close the shut-off valve on the hydrogen high-pressure circuit of the first high-pressure storage tank, and stop the pump from working.

[0048] The P _target 35MPa or 70MPa; V _tank_eff The effective volume of the high-pressure storage tank;

[0049] α: is the injection ratio, ranging from 0.95 to 0.98;

[0050] S105: First Switch

[0051] (1) Pre-balancing stage:

[0052] Open the throttling bypass valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank, and start the pump to inject liquid into the second high-pressure storage tank at a low flow rate; at the same time, open the throttling bypass valve of the shut-off valve at the liquid outlet of the first high-pressure storage tank to allow the high-pressure liquid in the first high-pressure storage tank to flow into the storage tank; until the gas phase pressure of the second high-pressure storage tank is close to the liquid phase pressure of the first high-pressure storage tank.

[0053] (2) Main valve opens:

[0054] When the pressure difference between the second high-pressure storage tank and the first high-pressure storage tank is less than a preset threshold, open the main valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank and the main valve of the shut-off valve at the liquid outlet of the first high-pressure storage tank; close the throttling bypass valve at the liquid inlet of the second high-pressure storage tank and the throttling bypass valve at the liquid outlet of the first high-pressure storage tank; the preset threshold is 0.2~0.5MPa, preferably 0.3MPa;

[0055] (3) Normal operation:

[0056] The pump continues to inject liquid into the second high-pressure storage tank to increase the pressure; the liquid in the first high-pressure storage tank flows back to the storage tank.

[0057] (4) Drainage and gas replenishment:

[0058] When the pressure in the first high-pressure storage tank drops to P1, the shut-off valve 3 on the hydrogen low-pressure circuit of the first high-pressure storage tank is opened, and low-pressure hydrogen enters the first high-pressure storage tank to completely discharge the residual liquid.

[0059] When the pressure of the second high-pressure storage tank reaches P _target And the injection volume reaches V _max When the pump stops working, first close the main valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank, then close the shut-off valve on the high-pressure hydrogen circuit of the second high-pressure storage tank.

[0060] (5) Complete the switch:

[0061] Close the main valve of the liquid outlet shut-off valve of the first high-pressure storage tank, and close the shut-off valve on the low-pressure hydrogen circuit of the first high-pressure storage tank.

[0062] The system enters the alternating cycle preparation state: the first high-pressure storage tank has been emptied and filled with low-pressure hydrogen, and the second high-pressure storage tank is filled with high-pressure liquid;

[0063] S106: Standard Alternating Cycle

[0064] S106a: Half-cycle A

[0065] (1) Pre-balancing: Open the throttling bypass valve at the liquid inlet of the first high-pressure storage tank and the throttling bypass valve at the outlet of the second high-pressure storage tank, start the pump to inject liquid into the first high-pressure storage tank at a low flow rate of 1~5 L / min, and at the same time, the liquid in the second high-pressure storage tank flows back to the storage tank; monitor the pressure difference before and after the liquid inlet shut-off valve of the first high-pressure storage tank and the pressure difference before and after the shut-off valve at the outlet of the second high-pressure storage tank;

[0066] (2) Main valve opening: When the pressure difference across the liquid inlet shut-off valve of the first high-pressure storage tank is less than 0.2~0.5MPa and the pressure difference across the shut-off valve at the outlet of the second high-pressure storage tank is less than 0.2~0.5MPa, open the main valve of the liquid inlet shut-off valve of the first high-pressure storage tank and the main valve of the shut-off valve at the outlet of the second high-pressure storage tank, and close the throttling bypass valve at the liquid inlet of the first high-pressure storage tank and the throttling bypass valve at the outlet of the second high-pressure storage tank;

[0067] (3) Normal operation: The pump injects liquid into the first high-pressure storage tank to increase the pressure; the liquid in the second high-pressure storage tank flows back to the storage tank; the high-pressure hydrogen is output to the high-pressure hydrogen output port through the high-pressure hydrogen circuit;

[0068] (4) Switching condition judgment: When the pressure of the first high-pressure storage tank reaches P _target And the injection volume reaches V _max Meanwhile, the liquid level in the second high-pressure storage tank is below the lower limit and the pressure drops to P. source When the pressure of the low-pressure hydrogen source is 3~5MPa, first close the main valve of the shut-off valve at the liquid inlet of the first high-pressure storage tank and the main valve of the shut-off valve at the liquid outlet of the second high-pressure storage tank, then close the throttling bypass valve at the liquid inlet of the first high-pressure storage tank and the throttling bypass valve at the liquid outlet of the second high-pressure storage tank, and enter S106b.

[0069] S106b: Half-cycle B

[0070] (1) Pre-balancing: Open the throttling bypass valve at the liquid inlet of the second high-pressure storage tank and the throttling bypass valve at the liquid outlet of the first high-pressure storage tank, start the pump to inject liquid into the second high-pressure storage tank at a low flow rate of 1~5 L / min, while the liquid in the first high-pressure storage tank flows into the storage tank, and monitor the pressure difference before and after the main valve.

[0071] (2) Main valve opening: When the pressure difference across the shut-off valve at the liquid inlet of the second high-pressure storage tank is less than 0.2~0.5MPa and the pressure difference across the shut-off valve at the outlet of the first high-pressure storage tank is less than 0.2~0.5MPa, open the main valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank and the main valve of the shut-off valve at the outlet of the first high-pressure storage tank, and close the throttling bypass valve at the liquid inlet of the second high-pressure storage tank and the throttling bypass valve at the outlet of the first high-pressure storage tank;

[0072] (3) Normal operation: The hydraulic pump injects liquid into the second high-pressure storage tank to increase the pressure; the liquid in the first high-pressure storage tank flows back to the storage tank; the high-pressure hydrogen in the second storage tank is output to the high-pressure hydrogen output port through the high-pressure hydrogen circuit;

[0073] Switching condition judgment: When the pressure of the second high-pressure storage tank 2 reaches P _target And the injection volume reaches V _max Meanwhile, the liquid level in the first high-pressure storage tank is below the lower limit and the pressure drops to P. sourceWhen the liquid phase inlet of the second high-pressure storage tank is closed, the main valve of the shut-off valve at the liquid phase inlet of the first high-pressure storage tank and the main valve of the shut-off valve at the liquid outlet of the first high-pressure storage tank are closed first. Then the throttling bypass valve at the liquid phase inlet of the second high-pressure storage tank and the throttling bypass valve at the liquid outlet of the first high-pressure storage tank are closed, and the process proceeds to S106a.

[0074] In the above method, the liquid is selected from high-purity mineral-based hydraulic oil, phosphate ester flame-retardant hydraulic oil, synthetic ester liquid, water-ethylene glycol solution, or perfluoropolyether liquid. High-purity mineral-based hydraulic oil is characterized by low cost, wide applicability, good compatibility with hydrogen, and suitability for conventional operating conditions and cost-sensitive scenarios. Flame-retardant hydraulic oil (phosphate ester) is characterized by excellent flame-retardant properties, but higher cost, suitable for applications with high fire protection requirements, such as indoor hydrogen refueling stations. Synthetic ester liquid is characterized by good chemical stability, excellent compatibility with hydrogen, and strong oxidation resistance, suitable for scenarios requiring long service life and low maintenance. Water-ethylene glycol solution is characterized by extremely strong chemical inertness and complete compatibility with hydrogen, suitable for special applications with extremely high purity requirements.

[0075] Compared with the prior art, the advantages of the present invention are:

[0076] 1. High safety: This invention completely eliminates the dynamic sealing leakage point of high-pressure hydrogen, and the safety is significantly improved compared with traditional booster equipment.

[0077] 2. High energy efficiency: This invention recovers the pressure energy of the drained liquid through a generator turbine and achieves efficient reuse through an energy storage battery, resulting in a significantly lower overall energy consumption than traditional booster equipment.

[0078] 3. High stability: The invention eliminates the pressure shock during switching by using soft switching technology, and the pressure fluctuation of high-pressure hydrogen output is less than ±2%, which meets the requirements of continuous and stable hydrogen dispensing by hydrogen dispensers.

[0079] 4. Low vibration and low noise: By eliminating the water hammer effect, the vibration and noise of the system are significantly reduced, thus improving the working environment.

[0080] 5. High reliability and low maintenance cost: There are no diaphragms, piston rings, screws and other vulnerable parts. The main maintenance targets are hydraulic pumps and valves. The maintenance cycle is long and the operation and maintenance cost is low.

[0081] 6. Grid interaction capability: The bidirectional inverter design enables the system to interact flexibly with the grid, adapting to the future development direction of smart energy networks.

[0082] 7. Compact structure and strong adaptability: Small size and light weight, suitable for application scenarios such as distributed hydrogen refueling stations and skid-mounted hydrogen refueling equipment. Attached Figure Description

[0083] Figure 1This is a schematic diagram of a distributed hydrogenation booster system based on hydraulic displacement according to the present invention. Detailed Implementation

[0084] The technical solutions described below, in conjunction with specific illustrations, are presented to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and similar extended embodiments made by those skilled in the art without inventive effort are all within the scope of protection of this invention.

[0085] Example 1

[0086] This embodiment provides a distributed hydrogen refueling and boosting system based on hydraulic displacement, such as... Figure 1 As shown, it consists of a first high-pressure storage tank 4.1, a second high-pressure storage tank 4.2, a hydrogen circuit, a hydraulic circuit, a soft switching valve group, an energy recovery electrical circuit, a safety protection unit, an auxiliary unit, and a controller.

[0087] The hydrogen circuit includes a low-pressure hydrogen circuit and a high-pressure hydrogen circuit. The low-pressure hydrogen inlet is connected to the first high-pressure storage tank 4.1 and the second high-pressure storage tank 4.2 through the low-pressure hydrogen circuit. The first high-pressure storage tank 4.1 and the second high-pressure storage tank 4.2 are connected to the high-pressure hydrogen outlet through the high-pressure hydrogen circuit. The low-pressure hydrogen circuit of the first high-pressure storage tank 4.1 is equipped with a third check valve 2.3 and a third shut-off valve 3.3. The low-pressure hydrogen circuit of the second high-pressure storage tank 4.2 is equipped with a fourth check valve 2.4 and a fifth shut-off valve 3.5. This circuit is used to alternately fill the high-pressure storage tank 1 and the high-pressure storage tank 2 with low-pressure hydrogen.

[0088] The first high-pressure storage tank 4.1 is equipped with a fourth shut-off valve 3.4 and a first check valve 2.1 in its high-pressure hydrogen circuit, while the second high-pressure storage tank 4.2 is equipped with a sixth shut-off valve 3.6 and a second check valve 2.2 in its high-pressure hydrogen circuit. Both the high-pressure hydrogen circuits of the first and second high-pressure storage tanks 4.1 are connected to a hydrogen purification and cooling device 1, which is connected to the high-pressure hydrogen outlet. This circuit is used to purify and cool the pressurized high-pressure hydrogen before delivering it to a hydrogen refueling terminal or a high-pressure storage container.

[0089] The hydraulic circuit includes a storage tank 6, a hydraulic pump 7, a buffer tank 8, a proportional flow valve 9, a fifth check valve 2.5, a sixth check valve 2.6, a first shut-off valve 3.1, a first throttling bypass valve 5.1, a second shut-off valve 3.2, and a second throttling bypass valve 5.2. The outlet of the storage tank 6 is sequentially connected to the hydraulic pump 7, the buffer tank 8, and the proportional flow valve 9. The proportional flow valve 9 is divided into two branches, which are connected to the first high-pressure storage tank 4.1 and the second high-pressure storage tank 4.2 respectively. A fifth check valve 2.5 and a first shut-off valve 3.1 are installed on the pipeline connected to the first high-pressure storage tank 4.1, and finally connected to the liquid phase inlet of the first high-pressure storage tank 4.1. A first throttling bypass valve 5.1 is connected in parallel to the first shut-off valve 3.1. A sixth check valve 2.6 and a second shut-off valve 3.2 are installed on the pipeline connected to the second high-pressure storage tank 4.2, and finally connected to the liquid phase inlet of the second high-pressure storage tank 4.2. A second throttling bypass valve 5.2 is connected in parallel to the second shut-off valve 3.2. This circuit is used to inject liquid from the storage tank into the high-pressure storage tank as needed to achieve hydraulic displacement pressurization. In this embodiment, the buffer tank is used to absorb the output pulsation of the hydraulic pump and buffer the pressure shock at the moment of switching, acting as an accumulator.

[0090] The outlet of the first high-pressure storage tank 4.1 is connected to the storage tank via a pipe. A seventh shut-off valve 3.7 is installed on the pipe, and a third throttling bypass valve 5.3 is connected in parallel to the seventh shut-off valve 3.7. The outlet of the second high-pressure storage tank 4.2 is connected to the storage tank via a pipe. An eighth shut-off valve 3.8 is installed on the pipe, and a fourth throttling bypass valve 5.4 is connected in parallel to the eighth shut-off valve 3.8. Specifically, as follows... Figure 1As shown, the outlet pipes of the seventh shut-off valve 3.7 and the eighth shut-off valve 3.8 are combined into a single pipe connected to the storage tank 6. This single pipe connects to the inlet of the turbine of the generator 11. The turbine inlet is sequentially connected to the rectifier 12, the energy storage battery 13, and the inverter 14. The inverter 14 is connected to the hydraulic pump 7. The storage tank 6 is equipped with a nitrogen-filled chamber 10, which is in direct contact with the liquid via a flexible diaphragm. An expansion bag, connected to the nitrogen chamber, absorbs volume fluctuations and absorbs volume changes caused by thermal expansion and contraction of the liquid. A nitrogen-filling port is located at the top of the storage tank to fill the space above the liquid surface with nitrogen, forming an inert gas protective layer to maintain positive pressure in the storage tank and prevent cavitation of the hydraulic pump. The outlet of the turbine of the generator 11 is connected to the upper return port of the storage tank 6 via a pipe. This circuit is used to return the high-pressure liquid from the high-pressure storage tank to the liquid storage tank, driving the turbine to generate electricity in the process. To facilitate liquid drainage, the installation height of the generator turbine should not be higher than the liquid phase interface of the high-pressure storage tank. The positional relationship between the high-pressure storage tank and the generator turbine directly affects the system performance. Specifically: the seventh and eighth shut-off valves should be as close as possible to the liquid phase interface of the high-pressure storage tank to reduce pipeline resistance losses. The generator turbine should be located downstream of the seventh and eighth shut-off valves, and its height can be lower than that of the storage tank to facilitate gravity flow of the liquid, but the main driving force is still the pressure difference, so its position is not strictly limited.

[0091] The gas phase interface of the first high-pressure storage tank 4.1 is connected to the inlet of the first safety valve 15.1 via a pipeline, and the gas phase interface of the second high-pressure storage tank 4.2 is connected to the inlet of the second safety valve 15.2 via a pipeline. The outlets of the first safety valve 15.1 and the second safety valve 15.2 are connected in parallel to the pressure relief port. When the pressure of either storage tank exceeds a set threshold, the corresponding safety valve automatically opens to relieve pressure.

[0092] To eliminate the water hammer effect during valve switching in this embodiment, throttling bypass valves are connected in parallel to the four key main valves (first shut-off valve 3.1, second shut-off valve 3.2, seventh shut-off valve 3.7, and eighth shut-off valve 3.8): the first shut-off valve 3.1 is connected in parallel to the first throttling bypass valve 5.1; the second shut-off valve 3.2 is connected in parallel to the second throttling bypass valve 5.2; the seventh shut-off valve 3.7 is connected in parallel to the third throttling bypass valve 5.3; and the eighth shut-off valve 3.8 is connected in parallel to the fourth throttling bypass valve 5.4. Each throttling bypass valve is a small-diameter solenoid valve (e.g., DN4~DN6) with an internal or series throttling orifice, used to limit the maximum flow rate when the bypass is open. During switching, the controller first opens the throttling bypass valve, and after the pressure difference across the main valve drops to a preset threshold (e.g., 0.3MPa), it operates the main valve and finally closes the throttling bypass valve, achieving a soft switching of "balancing before switching".

[0093] This embodiment also includes a sensor array:

[0094] Pressure sensors are installed at the following locations: 4.1 gas phase interface of the first high-pressure storage tank (including interfaces for low-pressure hydrogen circuit and high-pressure hydrogen circuit), 4.1 liquid phase interface of the first high-pressure storage tank (including liquid phase inlet and outlet), 4.2 gas phase interface of the second high-pressure storage tank (including interfaces for low-pressure hydrogen circuit and high-pressure hydrogen circuit), 4.2 liquid phase interface of the second high-pressure storage tank (including liquid phase inlet and outlet), hydraulic pump outlet pipeline, and buffer tank outlet.

[0095] Liquid level sensor: installed in the first high-pressure storage tank 4.1 and the second high-pressure storage tank 4.2, with redundant configuration (two independent liquid level sensors for each tank); Flow sensor: installed on the main pipeline between the outlet of the proportional flow valve and the fifth check valve 2.5 and the sixth check valve 2.6.

[0096] This embodiment also includes a controller, which is a programmable logic controller (PLC) or an embedded industrial controller. Its signal input terminal is connected to all pressure sensors, liquid level sensors, flow sensors, generator turbine power signals, and energy storage battery state of charge monitoring modules; its signal output terminal is connected to the electromagnetic actuators of all shut-off valves and their throttling bypass valves, the regulating mechanism of proportional flow valves, the frequency converter driver of hydraulic pumps, and the control terminals of inverters and bidirectional inverters.

[0097] Example 2

[0098] This embodiment provides a distributed hydrogenation boosting control method based on hydraulic displacement using the aforementioned system. This embodiment uses the system from Embodiment 1 and includes the following steps:

[0099] S101: System initialization: All shut-off valves are reset to the closed state, all throttling bypass valves are reset to the closed state, the controller performs a self-test, and checks the status of each sensor;

[0100] S102: Low-pressure pre-charge: Open the third shut-off valve 3.3 on the low-pressure hydrogen circuit of the first high-pressure storage tank and the fifth shut-off valve 3.5 on the low-pressure hydrogen circuit of the second high-pressure storage tank. Hydrogen enters the first high-pressure storage tank 4.1 and the second high-pressure storage tank 4.2 from the low-pressure hydrogen inlet. Monitor the pressure of the two tanks until they both reach the preset initial pressure P0. Then close the third shut-off valve 3.3 on the low-pressure hydrogen circuit of the first high-pressure storage tank 4.1 and the fifth shut-off valve 3.5 on the low-pressure hydrogen circuit of the second high-pressure storage tank 4.2. The preset initial pressure P0 is 4 MPa.

[0101] S103: Pressure Confirmation: Confirm that the pressure of the first high-pressure storage tank 4.1 and the second high-pressure storage tank 4.2 both reach the preset start threshold P1 of 4 MPa, where P1 = P0; if not, alarm and return to S102;

[0102] S103.5: Initial state settings:

[0103] (1) Open the first throttling bypass valve 5.1 of the first shut-off valve at the liquid inlet of the first high-pressure storage tank 4.1, start the hydraulic pump 7 to slowly inject liquid into the first high-pressure storage tank 4.1 at a low flow rate of 2 L / min, and monitor the change of gas phase pressure in the first high-pressure storage tank 4.1 at the same time;

[0104] (2) When the pressure inside the first high-pressure storage tank 4.1 rises steadily and there are no abnormal fluctuations, open the first shut-off valve 3.1 at the liquid phase inlet of the first high-pressure storage tank 4.1 and close the first throttling bypass valve 5.1;

[0105] (3) The hydraulic pump 7 dynamically adjusts the flow rate according to the pressure feedback and continues to inject liquid until the volume V0 is 80L; the setting of V0 must meet the following requirements: after injection, the hydrogen pressure P2 in the first high-pressure storage tank 4.1 is not higher than the target pressure P. _target (35 MPa) 80%, and the remaining gas phase space is not less than 10% of the effective volume;

[0106] (4) After reaching V0, first close the first shut-off valve 3.1 at the liquid inlet of the first high-pressure tank 4.1, and the hydraulic pump 7 stops working; at this time the system status is: the first high-pressure tank 4.1 contains liquid, and the internal pressure P2 is 20 MPa; the second high-pressure tank 4.2 has no liquid, and the internal pressure P1 is 4 MPa.

[0107] S104: First boost cycle

[0108] (1) Open the first throttling bypass valve 5.1 of the shut-off valve at the liquid inlet of the first high-pressure storage tank 4.1, start the hydraulic pump 7 to inject liquid into the first high-pressure storage tank 4.1 at a low flow rate, and when the pressure difference across the shut-off valve is less than the preset threshold of 0.3MPa, open the first shut-off valve 3.1 at the liquid inlet of the first high-pressure storage tank 4.1 and close the first throttling bypass valve 5.1;

[0109] (2) Open the fourth shut-off valve 3.4 at the high-pressure hydrogen circuit of the first high-pressure storage tank 4.1. The hydraulic pump 7 dynamically adjusts the flow rate according to the pressure change rate (pressure rise rate ≤ 1MPa / s) to smoothly compress the hydrogen in the first high-pressure storage tank 4.1 to the target pressure P. _target 35 MPa;

[0110] (3) The high-pressure hydrogen in the first high-pressure storage tank 4.1 is output from the high-pressure hydrogen outlet after passing through the hydrogen purification and cooling device 1;

[0111] (4) The second high-pressure storage tank is kept in an isolated state; the isolated state is as follows: the second shut-off valve 3.2 and the second throttling bypass valve 5.2 at the liquid inlet of the second high-pressure storage tank 4.2 are closed, the fifth shut-off valve 3.5 and the sixth shut-off valve 3.6 on the high-pressure hydrogen circuit and the low-pressure hydrogen circuit of the second high-pressure storage tank 4.2, the eighth shut-off valve 3.8 and the fourth throttling bypass valve 5.4 at the liquid outlet of the second high-pressure storage tank 4.2 are closed, and at the same time the third shut-off valve 3.3 on the low-pressure hydrogen circuit of the first high-pressure storage tank 4.1 is closed;

[0112] (5) When the pressure of the first high-pressure storage tank 4.1 reaches the target pressure P _target And the injection volume reaches V _max = α ×V _tank_eff (α = 0.98, V) _tank_eff When the volume is 100L, first close the first shut-off valve 3.1 at the liquid inlet of the first high-pressure storage tank 4.1, then close the fourth shut-off valve 3.4 on the hydrogen high-pressure circuit of the first high-pressure storage tank 4.1, and stop the operation of the hydraulic pump 7.

[0113] The P _target 35 MPa; V _tank_eff The effective volume of the high-pressure storage tank is 100L in this embodiment;

[0114] α: Injection ratio, taken as 0.98;

[0115] S105: First Switch

[0116] (1) Pre-balancing stage:

[0117] Open the second throttling bypass valve 5.2 of the second shut-off valve 3.2 at the liquid inlet of the second high-pressure storage tank 4.2, and start the hydraulic pump 7 to inject liquid into the second high-pressure storage tank 4.2 at a low flow rate; at the same time, open the third throttling bypass valve 5.3 of the seventh shut-off valve at the outlet of the first high-pressure storage tank 4.1, so that the high-pressure liquid in the first high-pressure storage tank 4.1 flows into the storage tank 6; until the gas phase pressure of the second high-pressure storage tank 4.2 is close to the liquid phase pressure of the first high-pressure storage tank 4.1;

[0118] (2) Main valve opens:

[0119] When the pressure difference between the second high-pressure storage tank 4.2 and the first high-pressure storage tank 4.1 is less than the preset threshold of 0.3 MPa, open the main valve of the second shut-off valve at the liquid inlet of the second high-pressure storage tank 4.2 and the main valve of the first shut-off valve at the liquid outlet of the first high-pressure storage tank 4.1; close the second throttling bypass valve 5.2 at the liquid inlet of the second high-pressure storage tank 4.2 and the third throttling bypass valve 5.3 at the liquid outlet of the first high-pressure storage tank 4.1.

[0120] (3) Normal operation:

[0121] Hydraulic pump 7 continues to inject liquid into the second high-pressure storage tank 4.2 to increase pressure; the liquid in the first high-pressure storage tank 4.1 flows back to the storage tank 6;

[0122] (4) Drainage and gas replenishment:

[0123] When the pressure in the first high-pressure storage tank 4.1 drops to P1, the shut-off valve 3 on the hydrogen low-pressure circuit of the first high-pressure storage tank is opened, and low-pressure hydrogen enters the first high-pressure storage tank 4.1, completely discharging the residual liquid.

[0124] When the pressure in the second high-pressure storage tank reaches P... _target And the injection volume reaches V _max When the time comes, first close the main valve of the second shut-off valve at the liquid phase inlet of the second high-pressure storage tank 4.2, then close the sixth shut-off valve 3.6 on the high-pressure hydrogen circuit of the second high-pressure storage tank 4.2, and the hydraulic pump 7 will stop working;

[0125] (5) Complete the switch:

[0126] Close the main valve of the seventh shut-off valve at the outlet of the first high-pressure storage tank 4.1, and close the third shut-off valve 3.3 on the low-pressure hydrogen circuit of the first high-pressure storage tank 4.1;

[0127] The system enters the alternating cycle preparation state: the first high-pressure storage tank 4.1 has been emptied and filled with low-pressure hydrogen, and the second high-pressure storage tank 4.2 is filled with high-pressure liquid;

[0128] S106: Standard Alternating Cycle

[0129] S106a: Half-cycle A

[0130] (1) Pre-balancing: Open the first throttling bypass valve 5.1 at the liquid inlet of the first high-pressure storage tank 4.1 and the fourth throttling bypass valve 5.4 at the outlet of the second high-pressure storage tank 4.2, start the pump to inject liquid into the first high-pressure storage tank 4.1 at a low flow rate of 2 L / min, and at the same time, the liquid in the second high-pressure storage tank 4.2 flows back to the storage tank 6; monitor the pressure difference before and after the first shut-off valve 3.1 at the liquid inlet of the first high-pressure storage tank 4.1 and the pressure difference before and after the eighth shut-off valve 3.8 at the outlet of the second high-pressure storage tank 4.2;

[0131] (2) Main valve opening: When the pressure difference across the first shut-off valve 3.1 at the liquid inlet of the first high-pressure tank 4.1 is less than 0.3 MPa and the pressure difference across the eighth shut-off valve 3.8 at the outlet of the second high-pressure tank 4.2 is less than 0.3 MPa, open the main valve of the first shut-off valve at the liquid inlet of the first high-pressure tank 4.1 and the main valve of the eighth shut-off valve at the outlet of the second high-pressure tank 4.2, and close the first throttling bypass valve 5.3 at the liquid inlet of the first high-pressure tank 4.1 and the fourth throttling bypass valve 5.4 at the outlet of the second high-pressure tank 4.2;

[0132] (3) Normal operation: Hydraulic pump 7 injects liquid into the first high-pressure storage tank 4.1 to increase pressure; liquid in the second high-pressure storage tank 4.2 flows back to the storage tank 6; high-pressure hydrogen is output to the high-pressure hydrogen output port through the high-pressure hydrogen circuit;

[0133] (4) Switching condition judgment: When the pressure of the first high-pressure storage tank 4.1 reaches P _target The pressure is 35 MPa and the injection volume reaches V. _max The level is 98L, and the liquid level in the second high-pressure storage tank 4.2 is below the lower limit and the pressure has dropped to P. source When the pressure of the low-pressure hydrogen source is 4MPa, first close the main valve of the first shut-off valve at the liquid inlet of the first high-pressure storage tank 4.1 and the main valve of the eighth shut-off valve at the liquid outlet of the second high-pressure storage tank 4.2, then close the first throttling bypass valve 5.1 at the liquid inlet of the first high-pressure storage tank 4.1 and the fourth throttling bypass valve 5.4 at the liquid outlet of the second high-pressure storage tank 4.2, and enter S106b;

[0134] S106b: Half-cycle B

[0135] (1) Pre-balancing: Open the second throttling bypass valve 5.2 at the liquid inlet of the second high-pressure storage tank 4.2 and the third throttling bypass valve 5.3 at the liquid outlet of the first high-pressure storage tank 4.1, start the pump to inject liquid into the second high-pressure storage tank 4.2 at a low flow rate of 2 L / min, while the liquid in the first high-pressure storage tank 4.1 flows into the storage tank 6, and monitor the pressure difference before and after the main valve;

[0136] (2) Main valve opening: When the pressure difference across the second shut-off valve 3.2 at the liquid inlet of the second high-pressure storage tank 4.2 is less than 0.3 MPa and the pressure difference across the seventh shut-off valve 3.7 at the outlet of the first high-pressure storage tank 4.1 is less than 0.3 MPa, open the main valve of the second shut-off valve at the liquid inlet of the second high-pressure storage tank 4.2 and the main valve of the seventh shut-off valve at the outlet of the first high-pressure storage tank 4.1, and close the second throttling bypass valve 5.2 at the liquid inlet of the second high-pressure storage tank 4.2 and the third throttling bypass valve 5.3 at the outlet of the first high-pressure storage tank 4.1;

[0137] (3) Normal operation: Hydraulic pump 7 injects liquid into the second high-pressure storage tank 4.2 to increase pressure; liquid in the first high-pressure storage tank 4.1 flows back to the storage tank 6; high-pressure hydrogen in the second storage tank 4.2 is output to the high-pressure hydrogen outlet through the high-pressure hydrogen circuit;

[0138] Switching condition judgment: When the pressure of the second high-pressure storage tank reaches P4.2 _target The pressure is 35 MPa and the injection volume reaches V. _max The pressure was 98L, and the liquid level in the first high-pressure storage tank 4.1 was below the lower limit and the pressure dropped to P. sourceWhen the pressure is 4 MPa, first close the main valve of the second shut-off valve at the liquid inlet of the second high-pressure storage tank 4.2 and the main valve of the seventh shut-off valve at the liquid outlet of the first high-pressure storage tank 4.1. Then close the second throttling bypass valve 5.2 at the liquid inlet of the second high-pressure storage tank 4.2 and the third throttling bypass valve 5.3 at the liquid outlet of the first high-pressure storage tank 4.1, and enter S106a.

[0139] In the above method, the liquid is selected from high-purity mineral-based hydraulic oil, phosphate ester flame-retardant hydraulic oil, synthetic ester liquid, water-ethylene glycol solution, or perfluoropolyether liquid. High-purity mineral-based hydraulic oil is characterized by low cost, wide applicability, good compatibility with hydrogen, and suitability for conventional operating conditions and cost-sensitive scenarios. Flame-retardant hydraulic oil (phosphate ester) is characterized by excellent flame-retardant properties, but higher cost, suitable for applications with high fire protection requirements, such as indoor hydrogen refueling stations. Synthetic ester liquid is characterized by good chemical stability, excellent compatibility with hydrogen, and strong oxidation resistance, suitable for scenarios requiring long service life and low maintenance. Water-ethylene glycol solution is characterized by extremely strong chemical inertness and complete compatibility with hydrogen, suitable for special applications with extremely high purity requirements.

[0140] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A distributed hydrogenation booster system based on hydraulic displacement, characterized in that, It includes at least two high-pressure storage tanks, a hydrogen circuit, and a hydraulic circuit; The hydrogen circuit includes a low-pressure hydrogen circuit and a high-pressure hydrogen circuit. The low-pressure hydrogen inlet is connected to the high-pressure storage tank through the low-pressure hydrogen circuit, and the high-pressure storage tank is connected to the high-pressure hydrogen outlet through the high-pressure hydrogen circuit. The number of low-pressure hydrogen circuits is the same as the number of high-pressure storage tanks, and the number of high-pressure hydrogen circuits is the same as the number of high-pressure storage tanks. The hydraulic circuit includes a storage tank and a pump; the storage tank is sequentially connected to the pump and the liquid phase inlet of the high-pressure storage tank; the outlet of the high-pressure storage tank is connected to the storage tank through pipes to form a hydraulic circuit.

2. The distributed hydrogenation booster system based on hydraulic displacement according to claim 1, characterized in that, The pump is one or more of the following: a hydraulic pump, a variable frequency drive pump, a variable displacement pump, a fixed displacement pump, and a proportional relief valve combined with a pump; the variable frequency drive pump adjusts the flow rate by changing the motor speed; the variable displacement pump changes the displacement by adjusting the swashplate angle; the fixed displacement pump combined with the proportional relief valve is a fixed displacement pump with a proportional relief valve, and the device achieves flow control through bypass adjustment. The pump is driven by an external power source or an energy storage power source. The energy storage power drive device includes a generator, a rectifier, an energy storage battery, and an inverter; the generator is connected in sequence to the rectifier, the energy storage battery, the inverter, and the pump. The turbine of the generator is installed at a height no higher than the liquid phase interface of the high-pressure storage tank.

3. The distributed hydrogenation booster system based on hydraulic displacement according to claim 1, characterized in that, Each high-pressure storage tank is equipped with a shut-off valve on its outlet pipe; a throttling bypass valve is connected in parallel to the shut-off valve.

4. The distributed hydrogenation booster system based on hydraulic displacement according to claim 1, characterized in that, A buffer tank and a proportional flow valve are provided between the pump and the liquid phase inlet of the high-pressure storage tank. The outlet of the proportional flow valve is divided into several branches, the number of which is the same as the number of high-pressure storage tanks. A check valve and a shut-off valve are provided on each branch, and a throttling bypass valve is connected in parallel to the shut-off valve. The buffer tank is replaced by an airbag accumulator, a piston accumulator, or a spring accumulator. The top of the storage tank is provided with a nitrogen filling port for filling the space above the liquid surface with nitrogen to form an inert gas protective layer, maintain positive pressure in the storage tank, and prevent pump cavitation; the storage tank is connected to the nitrogen filling chamber.

5. The distributed hydrogenation booster system based on hydraulic displacement according to claim 1, characterized in that, Each low-pressure hydrogen circuit is equipped with a check valve and a shut-off valve; each high-pressure hydrogen circuit is equipped with a check valve and a shut-off valve. The high-pressure hydrogen circuit is also equipped with a hydrogen purification and cooling device. The bottom of the high-pressure storage tank is also equipped with a gas phase interface, which is connected to the pressure relief port through a pipeline, and a safety valve is also installed on the pipeline. The number of high-pressure storage tanks is 2-5; The liquid outlet and liquid phase inlet are located at the bottom of the high-pressure storage tank.

6. The distributed hydrogenation booster system based on hydraulic displacement according to claim 1, characterized in that, It also includes sensors, including a pressure sensor, a liquid level sensor, and a flow sensor; the pressure sensor is installed at the following locations: the gas phase interface of the high-pressure storage tank, the liquid phase interface of the high-pressure storage tank, the outlet pipeline of the pump, and the outlet of the buffer tank; the liquid level sensor is installed inside the high-pressure storage tank, with two independent liquid level sensors installed in each tank; the flow sensor is installed on the main pipeline between the outlet of the proportional flow valve and the check valve.

7. A distributed hydrogenation boosting control method based on hydraulic displacement using the system described in any one of claims 1 to 6, characterized in that, First, all high-pressure storage tanks are pre-charged with low-pressure hydrogen to ensure that the pressure in all high-pressure storage tanks reaches the preset initial pressure; liquid is injected into the first high-pressure storage tank to perform pressurization and hydrogen supply operation; then, the first switch is performed to put the system into the preparatory state of alternating cycle, and then all high-pressure storage tanks are subjected to standard alternating cycle; the alternating cycle includes pressurizing the first high-pressure storage tank and draining liquid from a non-first high-pressure storage tank, or pressurizing a non-first high-pressure storage tank and draining liquid from the first high-pressure storage tank; The steps for injecting liquid into the first high-pressure storage tank to pressurize and supply hydrogen are as follows: open the valve at the liquid inlet of the first high-pressure storage tank, start the pump to inject liquid into the first high-pressure storage tank, then open the valve on the high-pressure hydrogen circuit of the first high-pressure storage tank. The pump dynamically adjusts the flow rate according to the pressure change rate, so that the hydrogen in the first high-pressure storage tank is stably compressed to the target pressure P_. target High-pressure hydrogen is output through the high-pressure hydrogen outlet after passing through the high-pressure circuit. At this time, non-first high-pressure storage tanks are in an isolated state. When the pressure in the first high-pressure storage tank reaches the target pressure P... _target And the injection volume reaches V _max = α × V _tank_eff When this happens, first close the valve at the liquid inlet, then close the valve on the high-pressure circuit to stop the pump from operating; The α is the injection ratio, ranging from 0.95 to 0.98; the V _tank_eff The effective volume of the high-pressure storage tank; The first switching operation is as follows: First, balance the pressure in all high-pressure storage tanks so that the pressures are close; continuously inject liquid to pressurize the non-first high-pressure storage tanks, while the liquid in the first high-pressure storage tank continuously flows back to the storage tank; when the pressure in the first high-pressure storage tank drops to a set threshold, inject low-pressure hydrogen to completely discharge the remaining liquid; when the pressure in any of the non-first high-pressure storage tanks reaches a predetermined threshold, stop injecting liquid into the non-first high-pressure storage tanks and discharging high-pressure hydrogen, while simultaneously stop discharging liquid from the first high-pressure storage tank and inputting low-pressure hydrogen, so that the system enters the preparatory state of alternating cycle; the preparatory state of alternating cycle is that the first high-pressure storage tank has been emptied and filled with low-pressure hydrogen, and any of the non-first high-pressure storage tanks is filled with high-pressure liquid; The isolation state of the non-first high-pressure storage tank is as follows: the shut-off valves on the low-pressure hydrogen circuit and the high-pressure hydrogen circuit of the non-first high-pressure storage tank are closed, the shut-off valves and throttling bypass valves on the liquid inlet and outlet of the other high-pressure storage tanks are closed, and the shut-off valve on the low-pressure hydrogen circuit of the high-pressure storage tank is closed.

8. The control method according to claim 7, characterized in that, The specific operation of the first switching is as follows: Open the liquid inlet valve of the selected non-first high-pressure storage tank, start the pump, and inject liquid into the non-first high-pressure storage tank. At the same time, open the outlet valve of the first high-pressure storage tank to allow high-pressure liquid to flow into the storage tank. When the liquid pressure difference between the two high-pressure storage tanks is less than a preset threshold, open the liquid inlet valve of the non-first high-pressure storage tank and the outlet valve of the first high-pressure storage tank to inject liquid and pressurize the non-first high-pressure storage tank. When the pressure in the first high-pressure storage tank drops to P1, open all valves on the low-pressure hydrogen circuit of the first high-pressure storage tank, and low-pressure hydrogen enters the first high-pressure storage tank to completely discharge the residual liquid. When the pressure in the non-first high-pressure storage tank reaches P... _target And the injection volume reaches V _max When switching is complete, first close the valve at the liquid inlet of the non-first high-pressure storage tank, then close the valve at the high-pressure hydrogen circuit of the non-first high-pressure storage tank, stop the pump operation, and then close the valve at the liquid outlet of the first high-pressure storage tank and the valve at the low-pressure hydrogen circuit of the first high-pressure storage tank.

9. The control method according to claim 7, characterized in that, When the system is started for the first time, before the pressurization and hydrogen supply step of the high-pressure storage tank, an initial state setting operation is required. The initial state setting operation can be: one high-pressure storage tank is injected with liquid while the other high-pressure storage tanks are on standby, or each high-pressure storage tank is partially injected with liquid and then enters the pressurization and liquid discharge cycle in sequence.

10. The control method according to claim 7, characterized in that, When there are two high-pressure storage tanks, the control method includes the following steps: S101: System Initialization All shut-off valves are reset to the closed position, all throttling bypass valves are reset to the closed position, the controller performs a self-test, and checks the status of each sensor; S102: Low-voltage pre-charge: Open the shut-off valves on the low-pressure hydrogen circuit of the first high-pressure storage tank and the low-pressure hydrogen circuit of the second high-pressure storage tank. Hydrogen gas enters the first and second high-pressure storage tanks from the low-pressure hydrogen inlet. Monitor the pressure in both tanks until they both reach the preset initial pressure P0. Then close the shut-off valves on the low-pressure hydrogen circuits of the first and second high-pressure storage tanks. The preset initial pressure P0 is 3~5MPa. S103: Pressure Confirmation: Confirm that the pressure of both the first high-pressure storage tank and the second high-pressure storage tank has reached the preset start threshold P1, where P1 = P0; if not, trigger an alarm and return to S102. S103.5: Initial state settings: (1) Open the throttling bypass valve of the shut-off valve at the liquid inlet of the first high-pressure storage tank, start the pump to slowly inject liquid into the first high-pressure storage tank at a low flow rate, and monitor the change of gas phase pressure in the first high-pressure storage tank at the same time; the low flow rate is 1~5 L / min; (2) When the pressure inside the first high-pressure storage tank rises steadily and there are no abnormal fluctuations, open the shut-off valve at the liquid phase inlet of the first high-pressure storage tank and close the throttling bypass valve. (3) The pump dynamically adjusts the flow rate based on pressure feedback and continues to inject liquid to a volume V0; the setting of V0 must meet the following condition: after injection, the hydrogen pressure P2 in the first high-pressure storage tank is not higher than the target pressure P. _target 60% to 80% of the volume, and the remaining gas phase space is not less than 10% of the effective volume; (4) After reaching V0, first close the shut-off valve at the liquid inlet of the first high-pressure tank and the pump stops working; at this time the system status is: the first high-pressure tank has liquid and the internal pressure is P2; the second high-pressure tank has no liquid and the internal pressure is P1. S104: First boost cycle (1) Open the throttling bypass valve of the shut-off valve at the liquid phase inlet of the first high-pressure storage tank, start the pump to inject liquid into the first high-pressure storage tank at a low flow rate, and when the pressure difference across the shut-off valve is less than the preset threshold, open the shut-off valve at the liquid phase inlet of the first high-pressure storage tank and close the throttling bypass valve; the preset threshold is 0.2~0.5MPa; (2) Open the shut-off valve at the high-pressure hydrogen circuit of the first high-pressure storage tank. The pump dynamically adjusts the flow rate according to the pressure change rate to smoothly compress the hydrogen in the first high-pressure storage tank to the target pressure P. _target ; (3) The high-pressure hydrogen in the first high-pressure storage tank is output from the high-pressure hydrogen outlet after passing through the hydrogen purification and cooling device; (4) The second high-pressure storage tank is kept in an isolated state; the isolated state is as follows: the shut-off valve and the throttling bypass valve at the liquid inlet of the second high-pressure storage tank are closed, the shut-off valves on the high-pressure hydrogen circuit and the low-pressure hydrogen circuit of the second high-pressure storage tank, the shut-off valve and the throttling bypass valve at the liquid outlet of the second high-pressure storage tank are closed, and the shut-off valve on the low-pressure hydrogen circuit of the first high-pressure storage tank is closed. (5) When the pressure of the first high-pressure storage tank reaches the target pressure P _target And the injection volume reaches V _max = α × V _tank_eff When the pump stops, first close the shut-off valve at the liquid inlet of the first high-pressure storage tank, then close the shut-off valve on the hydrogen high-pressure circuit of the first high-pressure storage tank, and stop the pump from working. The P _target 35MPa or 70MPa; V _tank_eff The effective volume of the high-pressure storage tank; α: is the injection ratio, ranging from 0.95 to 0.98; S105: First Switch (1) Pre-balancing stage: Open the throttling bypass valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank, and start the pump to inject liquid into the second high-pressure storage tank at a low flow rate; at the same time, open the throttling bypass valve of the shut-off valve at the liquid outlet of the first high-pressure storage tank to allow the high-pressure liquid in the first high-pressure storage tank to flow into the storage tank; until the gas phase pressure of the second high-pressure storage tank is close to the liquid phase pressure of the first high-pressure storage tank. (2) Main valve opens: When the pressure difference between the second high-pressure storage tank and the first high-pressure storage tank is less than a preset threshold, open the main valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank and the main valve of the shut-off valve at the liquid outlet of the first high-pressure storage tank; close the throttling bypass valve at the liquid inlet of the second high-pressure storage tank and the throttling bypass valve at the liquid outlet of the first high-pressure storage tank; the preset threshold is 0.2~0.5MPa; (3) Normal operation: The pump continues to inject liquid into the second high-pressure storage tank to increase the pressure; the liquid in the first high-pressure storage tank flows back to the storage tank. (4) Drainage and gas replenishment: When the pressure in the first high-pressure storage tank drops to P1, the shut-off valve 3 on the hydrogen low-pressure circuit of the first high-pressure storage tank is opened, and low-pressure hydrogen enters the first high-pressure storage tank to completely discharge the residual liquid. When the pressure of the second high-pressure storage tank reaches P _target And the injection volume reaches V _max When the pump stops working, first close the main valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank, then close the shut-off valve on the high-pressure hydrogen circuit of the second high-pressure storage tank. (5) Complete the switch: Close the main valve of the liquid outlet shut-off valve of the first high-pressure storage tank, and close the shut-off valve on the low-pressure hydrogen circuit of the first high-pressure storage tank. The system enters the alternating cycle preparation state: the first high-pressure storage tank has been emptied and filled with low-pressure hydrogen, and the second high-pressure storage tank is filled with high-pressure liquid; S106: Standard Alternating Cycle S106a: Half-cycle A (1) Pre-balancing: Open the throttling bypass valve at the liquid inlet of the first high-pressure storage tank and the throttling bypass valve at the liquid outlet of the second high-pressure storage tank, start the pump to inject liquid into the first high-pressure storage tank at a low flow rate of 1~5 L / min, and at the same time, the liquid in the second high-pressure storage tank flows back to the storage tank. Monitor the pressure difference across the liquid inlet shut-off valve of the first high-pressure storage tank and the pressure difference across the shut-off valve at the outlet of the second high-pressure storage tank; (2) Main valve opening: When the pressure difference across the liquid inlet shut-off valve of the first high-pressure storage tank is less than 0.2~0.5MPa and the pressure difference across the shut-off valve at the outlet of the second high-pressure storage tank is less than 0.2~0.5MPa, open the main valve of the liquid inlet shut-off valve of the first high-pressure storage tank and the main valve of the shut-off valve at the outlet of the second high-pressure storage tank, and close the throttling bypass valve at the liquid inlet of the first high-pressure storage tank and the throttling bypass valve at the outlet of the second high-pressure storage tank; (3) Normal operation: The pump injects liquid into the first high-pressure storage tank to increase the pressure; the liquid in the second high-pressure storage tank flows back to the storage tank; the high-pressure hydrogen is output to the high-pressure hydrogen output port through the high-pressure hydrogen circuit; (4) Switching condition judgment: When the pressure of the first high-pressure storage tank reaches P _target And the injection volume reaches V _max Meanwhile, the liquid level in the second high-pressure storage tank is below the lower limit and the pressure drops to P. source， When the low-pressure hydrogen source pressure is 3~5MPa, first close the main valve of the shut-off valve at the liquid inlet of the first high-pressure storage tank and the main valve of the shut-off valve at the liquid outlet of the second high-pressure storage tank, then close the throttling bypass valve at the liquid inlet of the first high-pressure storage tank and the throttling bypass valve at the liquid outlet of the second high-pressure storage tank, and enter S106b. S106b: Half-cycle B (1) Pre-balancing: Open the throttling bypass valve at the liquid inlet of the second high-pressure storage tank and the throttling bypass valve at the liquid outlet of the first high-pressure storage tank, start the pump to inject liquid into the second high-pressure storage tank at a low flow rate of 1~5 L / min, while the liquid in the first high-pressure storage tank flows into the storage tank, and monitor the pressure difference before and after the main valve. (2) Main valve opening: When the pressure difference across the shut-off valve at the liquid inlet of the second high-pressure storage tank is less than 0.2~0.5MPa and the pressure difference across the shut-off valve at the outlet of the first high-pressure storage tank is less than 0.2~0.5MPa, open the main valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank and the main valve of the shut-off valve at the outlet of the first high-pressure storage tank, and close the throttling bypass valve at the liquid inlet of the second high-pressure storage tank and the throttling bypass valve at the outlet of the first high-pressure storage tank; (3) Normal operation: The hydraulic pump injects liquid into the second high-pressure storage tank to increase the pressure; the liquid in the first high-pressure storage tank flows back to the storage tank; the high-pressure hydrogen in the second storage tank is output to the high-pressure hydrogen output port through the high-pressure hydrogen circuit; Switching condition judgment: When the pressure of the second high-pressure storage tank 2 reaches P _target And the injection volume reaches V _max Meanwhile, the liquid level in the first high-pressure storage tank is below the lower limit and the pressure drops to P. source When the time comes, first close the main valve of the shut-off valve at the liquid inlet of the second high-pressure storage tank and the main valve of the shut-off valve at the liquid outlet of the first high-pressure storage tank, then close the throttling bypass valve at the liquid inlet of the second high-pressure storage tank and the throttling bypass valve at the liquid outlet of the first high-pressure storage tank, and enter S106a; The liquid is selected from high-purity mineral-based hydraulic oil, phosphate ester flame-retardant hydraulic oil, synthetic ester liquid, water-ethylene glycol solution, or perfluoropolyether liquid.

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