Green hydrogen supply system with hydrogen storage branch

Abstract

The utility model discloses a green hydrogen supply system with a hydrogen storage branch, which comprises a hydrogen production unit, the hydrogen output end of the hydrogen production unit is connected with the input end of a buffer tank through a main pipeline and a branch pipeline which are connected in parallel, the buffer tank is connected with a buffer tank pressure gauge, and the output end of the buffer tank is connected with an outlet compressor. The output end of the outlet compressor is connected with a system outlet; the branch pipeline comprises a storage tank inlet regulating valve, a hydrogen storage tank, an auxiliary valve group and a storage tank outlet compressor which are sequentially arranged in the hydrogen conveying direction; the hydrogen storage tank and auxiliary valve group comprises a plurality of hydrogen storage tanks which are connected in parallel; the input end and the output end of the storage tank outlet compressor are further connected with a storage tank outlet compressor bypass pipeline, and the storage tank outlet compressor bypass pipeline comprises a bypass adjusting valve and a bypass check valve which are connected in series. According to the scheme, under the condition that the hydrogen production amount fluctuates, it is guaranteed that the flow of downstream hydrogen supply is stable, the pressure of upstream hydrogen is utilized to the maximum extent, and compression power consumption is reduced.

Description

Technical Field

[0001] The utility model belongs to the technical field of comprehensive utilization of hydrogen energy, and specifically relates to a green hydrogen supply system with a hydrogen storage branch. Background Art

[0002] By utilizing renewable energy sources such as wind and photovoltaic power generation and producing hydrogen through water electrolysis, energy can be stored, transported, and utilized in the form of hydrogen. Further utilizing hydrogen to replace traditional fossil fuels like coal and oil can achieve decarbonization in transportation, metallurgy, and the chemical industry.

[0003] Hydrogen production based on renewable energy is characterized by the volatility of upstream power sources. To fully absorb the electricity generated by wind and solar power and reduce the system's dependence on the public grid, the load of the hydrogen production process follows the output of the power generation process in real time, causing the hydrogen production rate to fluctuate by the same magnitude. This is detrimental to downstream hydrogen utilization. Downstream consumption processes, such as chemical and metallurgical industries, typically require a relatively stable hydrogen supply flow rate. Even if fluctuations within a certain range are allowed, they can only withstand relatively slow changes, which is incompatible with the rapid and large fluctuations in upstream wind and solar power generation. The solution is to add a certain number of hydrogen storage tanks as a transit point, decoupling hydrogen production from hydrogen consumption and absorbing short-term fluctuations in hydrogen flow, thereby ensuring a more stable hydrogen supply for downstream processes.

[0004] The process flow and control of the hydrogen storage system need to be optimized to give full play to the ability of hydrogen storage to regulate volatility, improve the energy efficiency of the entire system, and enhance the corresponding capabilities. For example, hydrogen generally has a certain pressure at the outlet of the hydrogen production process, usually 1.5MPa-3.0MPa, but the hydrogen pressure in the storage tank varies with the reserves and is generally lower than the pressure at the hydrogen production outlet. Therefore, it needs to be compressed again and consumes electricity when supplied to the downstream. To ensure the energy efficiency of the system, unnecessary decompression should be avoided as much as possible. In addition, the operating range and movement speed of the valves and compressors in the system are limited, resulting in the inability of flow control to respond in a timely manner. Utility Model Content

[0005] The technical problem to be solved by the present invention is to provide a green hydrogen supply system with a hydrogen storage branch, so as to solve the problem in the existing solution that the pressure of the storage tank used for gas supply varies greatly and is lower than the required gas pressure, thereby consuming more electricity during re-compression during gas supply. Through the structure and control strategy, unnecessary decompression can be avoided, thereby reducing the power consumption of the system.

[0006] According to the technical solution of the present invention, the present invention provides a green hydrogen supply system with a hydrogen storage branch, including a hydrogen production unit, the hydrogen output end of the hydrogen production unit is connected to the input end of a buffer tank through a main pipeline and a branch pipeline connected in parallel, the buffer tank is connected to a buffer tank pressure gauge, the output end of the buffer tank is connected to an outlet compressor, and the output end of the outlet compressor is connected to the system outlet; the branch pipeline includes a tank inlet regulating valve, a hydrogen storage tank and an auxiliary valve group and a tank outlet compressor arranged in sequence along the hydrogen transportation direction; the hydrogen storage tank and the auxiliary valve group include several hydrogen storage tanks connected in parallel; the tank outlet compressor bypass pipeline is also connected to the input and output ends of the tank outlet compressor, and the tank outlet compressor bypass pipeline includes a bypass regulating valve and a bypass check valve connected in series.

[0007] Furthermore, the bypass regulating valve is located on a side close to the input end of the compressor at the tank outlet, and the bypass check valve is located on a side close to the output end of the compressor at the tank outlet.

[0008] Furthermore, the hydrogen production unit is a renewable energy hydrogen production unit, which is connected to a renewable energy power generation system, which is a wind power generation system, a photovoltaic power generation system and / or a power generation system combining wind power generation and photovoltaic power generation.

[0009] Furthermore, each hydrogen storage tank is provided with an auxiliary valve.

[0010] Furthermore, the bypass check valve is a one-way valve that conducts in the direction from the output end to the input end of the tank outlet compressor; and / or, the tank outlet compressor is a compressor with flow regulation capability.

[0011] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0012] The green hydrogen supply system and method with a hydrogen storage branch of the present invention is located between upstream electrolytic hydrogen production and downstream hydrogen energy utilization in the integrated green hydrogen preparation and utilization system. Combined with the responsive control strategy, it can ensure the stability of the downstream hydrogen supply flow when the hydrogen production fluctuates, maximize the utilization of the upstream hydrogen pressure, and reduce compression power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a structural schematic diagram of a green hydrogen supply system with a hydrogen storage branch according to an embodiment of the present invention.

[0014] Description of reference numerals in the accompanying drawings:

[0015] 1. Hydrogen production unit; 11. Main pipeline; 12. Branch pipeline; 2. Tank inlet regulating valve; 3. Hydrogen storage tank and auxiliary valve group; 4. Tank outlet compressor; 5. Tank outlet compressor bypass pipeline; 51. Bypass regulating valve; 52. Bypass check valve; 6. Buffer tank; 7. Buffer tank pressure gauge; 8. Export compressor. DETAILED DESCRIPTION

[0016] The utility model provides a stable hydrogen supply technology coupled with hydrogen production from a fluctuating power source, specifically a green hydrogen supply system with a hydrogen storage branch. It solves the problem in existing solutions that the pressure of the storage tank used for gas supply varies greatly and is lower than the required gas pressure, resulting in a high consumption of electrical energy for recompression during gas supply. Through the structure and control strategy, unnecessary decompression is avoided, thereby reducing system power consumption.

[0017] See also Figure 1 A green hydrogen supply system with a hydrogen storage branch according to an embodiment of the present invention includes a hydrogen production unit 1. The hydrogen output end of the hydrogen production unit 1 is connected to the input end of a buffer tank 6 through a main pipeline 11 and a branch pipeline 12 connected in parallel. The buffer tank 6 is connected to a buffer tank pressure gauge 7 to monitor the pressure (or pressure, for example, in MPa) of the buffer tank 6 in real time. The output end of the buffer tank 6 is connected to an outlet compressor 8. The output end of the outlet compressor 8 is connected to the system outlet and then connected to a downstream hydrogen utilization (consumption) system, such as for chemical, metallurgical and other applications.

[0018] The branch line 12 includes a tank inlet regulating valve 2, a hydrogen tank and its auxiliary valve group 3 and a tank outlet compressor 4 arranged in sequence along the hydrogen delivery direction. The hydrogen tank and its auxiliary valve group 3 includes several hydrogen tanks connected in parallel, such as Figure 1 3a, 3b, etc.; there are preferably more than two hydrogen storage tanks, each equipped with an auxiliary valve to control its input / output; to a certain extent, the more hydrogen storage tanks connected in parallel, the more flexible the control and the more helpful it is in ensuring the pressure stability in the buffer tank 6. The input and output ends of the tank outlet compressor 4 are also connected to the tank outlet compressor bypass line 5, which includes a bypass regulating valve 51 and a bypass check valve 52 connected in series.

[0019] More specifically, the hydrogen production unit 1 is a renewable energy hydrogen production unit, and the hydrogen production unit 1 is connected to a renewable energy power generation system. The renewable energy power generation system is, for example, a wind power generation system, a photovoltaic power generation system and / or a power generation system combining wind power generation and photovoltaic power generation. The output power of the renewable energy power generation system fluctuates greatly, so the hydrogen production flow rate of the hydrogen production unit 1 also fluctuates greatly, and is generally different from the hydrogen flow rate at the outlet of the system. Therefore, the pressure in the buffer tank 6 will fluctuate up and down, resulting in the aforementioned high power consumption and other problems. The function of the hydrogen storage branch (branch pipeline 21) of this scheme is to maintain the pressure of the buffer tank 6 within a relatively high, stable and controllable range, thereby helping to reduce power consumption and being able to form the pressure and flow required downstream more quickly.

[0020] The bypass check valve 52 is a one-way valve that conducts in the direction from the output end to the input end of the tank outlet compressor 4. The bypass regulating valve 51 is located on the side close to the input end of the tank outlet compressor 4, and the bypass check valve 52 is located on the side close to the output end of the tank outlet compressor 4, thereby ensuring the function of the tank outlet compressor bypass pipeline 5 and ensuring that hydrogen flows according to the following method process of the present invention.

[0021] The basic process and principle of the green hydrogen supply method with a hydrogen storage branch of the present invention are as follows. The hydrogen coming out of the hydrogen production unit 1, assuming its pressure is 1.5MPa, directly enters the buffer tank 6 in one way, called the main pipeline 11, and can enter the branch pipeline 12 in the other way to flow into hydrogen storage tanks such as 3a and 3b, but the tank inlet regulating valve 2 will control the opening and closing and flow rate. In addition to the hydrogen flow directly from the hydrogen production unit 1, the inlet of the buffer tank 6 can also receive hydrogen released from hydrogen storage tanks such as 3a and 3b, which is recompressed to 1.5MPa and then merged into the main pipeline. The flow rate is controlled by the tank outlet compressor 4 and its bypass (tank outlet compressor bypass pipeline 5).

[0022] More specifically, a green hydrogen supply method with a hydrogen storage branch according to an embodiment of the present invention adopts a green hydrogen supply system with a hydrogen storage branch according to the present invention, which includes the following mode 1 and mode 2.

[0023] During Mode 1 and Mode 2, the outlet compressor 8 extracts hydrogen from the buffer tank 6, compresses it, and then delivers it based on the downstream hydrogen consumption flow and pressure requirements. Therefore, when the amount of hydrogen output from the buffer tank 6 is greater than the amount of hydrogen input, the pressure in the buffer tank 6 will decrease; conversely, when the amount of hydrogen output from the buffer tank 6 is less than the amount of hydrogen input, the pressure in the buffer tank 6 will increase.

[0024] Mode 1 includes the following process: when the pressure of the buffer tank 6 is greater than or equal to the first pressure P1, the tank inlet regulating valve 2 is opened, so that a part of the hydrogen produced by the hydrogen production unit 1 directly enters the buffer tank 6 through the main pipeline 11, and the other part enters the hydrogen storage tank through the branch pipeline 12, and the tank outlet compressor 4 does not supply hydrogen to the buffer tank 6, and the flow distribution of the main pipeline 11 and the branch pipeline 12 is controlled by the tank inlet regulating valve 2; the flow in the main pipeline 11 is reduced, so that the pressure of the buffer tank 6 is reduced; when the pressure of the buffer tank 6 drops to the second pressure P2, the tank inlet regulating valve 2 is closed, so that the hydrogen produced by the hydrogen production unit 1 directly enters the buffer tank 6 through the main pipeline 11; when the pressure of the buffer tank 6 is always greater than the third pressure P3, the process of mode 1 is repeated, so that the pressure of the buffer tank 6 basically does not exceed the first pressure P1; when the pressure of the buffer tank 6 drops to the third pressure P3, it switches to mode 2.

[0025] Mode 2 includes the following process: when the pressure of the buffer tank 6 is less than or equal to the third pressure P3, the tank outlet compressor 4 extracts hydrogen from the hydrogen storage tank, compresses it and then transports it to the buffer tank 6, and its flow rate is controlled by the tank outlet compressor 4 and the tank outlet compressor bypass pipeline 5; the pressure of the buffer tank 6 will increase; when the pressure of the buffer tank 6 rises back to above the second pressure P2, the tank outlet compressor 4 stops transporting hydrogen to the buffer tank 6 and switches to mode 1 operation; in this way, the pressure of the buffer tank 6 is basically not lower than the third pressure P3.

[0026] The first pressure P1 is greater than the second pressure P2, which is greater than the third pressure P3. For example, the difference between the first pressure P1 and the second pressure P2 is 0.1 MPa ± 0.05 MPa, and the difference between the second pressure P2 and the third pressure P3 is 0.1 MPa ± 0.05 MPa. Specifically, for example, the first pressure P1 = 1.5 MPa, the second pressure P2 = 1.4 MPa, and the third pressure P3 = 1.3 MPa. The specific values ​​can be adjusted based on actual conditions. A small difference between P1, P2, and P3 can help save compression power consumption in the outlet compressor 8, but it also results in frequent mode switching and high control requirements. The opposite is also true.

[0027] In the above process, "basically not exceeding" and "basically not lower than" mean that, generally speaking, the pressure change in the buffer tank 6 will not be very rapid. Usually, it is possible to immediately perform corresponding control after detecting that the pressure reaches 1.5 MPa, so that the pressure does not exceed 1.5 MPa. In special circumstances, the pressure may exceed the range between the first pressure P1 and the third pressure P3, but will not exceed by much, for example, exceeding the range by 0.05 MPa, which is within the controllable range.

[0028] In a preferred embodiment, in mode 2, the tank outlet compressor 4 compresses the hydrogen to a first pressure P1 (eg, 1.5 MPa) and then delivers it to the buffer tank 6, thereby ensuring that the buffer tank 6 stabilizes at a set pressure level more quickly with relatively low power consumption.

[0029] In a preferred embodiment, the bypass check valve 52 is a one-way valve that conducts in the direction from the output end to the input end of the tank outlet compressor 4. The tank outlet compressor 4 always remains in operation. When the tank outlet compressor 4 does not deliver hydrogen to the buffer tank 6, the bypass regulating valve 51 is in an open (conducting) state, and the hydrogen output by the tank outlet compressor 4 is recycled to the input end of the tank outlet compressor 4 through the tank outlet compressor bypass pipeline 5; when the tank outlet compressor 4 delivers hydrogen to the buffer tank 6, the bypass regulating valve 51 is in a closed (blocked) state. The concept and function of this scheme is that although the process of hydrogen supply from the hydrogen storage tank to the main road does not continue all the time, but is only carried out when necessary, considering that the tank outlet compressor 4 is inconvenient to start and stop frequently and has a slow starting speed, the tank outlet compressor 4 is generally maintained in an operating state, and hydrogen is recycled to the inlet of the outlet compressor 4 through the tank outlet compressor bypass pipeline 5 when gas supply is not needed.

[0030] Further preferably, the tank outlet compressor 4 is a compressor with flow regulation capability. In this solution, since the tank outlet compressor 4 has load regulation capability, when the tank outlet compressor 4 is not delivering hydrogen to the buffer tank 6, the load of the tank outlet compressor 4 can be adjusted to the minimum to save electricity.

[0031] In summary, the green hydrogen supply system and method with a hydrogen storage branch in this utility model is located between upstream electrolytic hydrogen production and downstream hydrogen energy utilization in an integrated green hydrogen production and utilization system. Combined with a responsive control strategy, it ensures a stable downstream hydrogen supply flow rate despite fluctuations in hydrogen production, maximizes upstream hydrogen pressure, and reduces compression power consumption. In a specific embodiment, the hydrogen storage branch can maintain the buffer tank pressure within a certain range, close to 1.5 MPa, for example, allowing it to fluctuate between 1.3 MPa and 1.5 MPa.

Claims

1. A green hydrogen supply system with a hydrogen storage branch, It is characterized in that The invention comprises a hydrogen production unit (1), wherein the hydrogen output end of the hydrogen production unit (1) is connected to the input end of a buffer tank (6) through a main pipeline (11) and a branch pipeline (12) connected in parallel, the buffer tank (6) is connected to a buffer tank pressure gauge (7), the output end of the buffer tank (6) is connected to an outlet compressor (8), and the output end of the outlet compressor (8) is connected to the system outlet; the branch pipeline (12) comprises a tank inlet regulating valve (2), a hydrogen tank and an auxiliary valve group (3), and a tank outlet compressor (4) arranged in sequence along the hydrogen transport direction; the hydrogen tank and an auxiliary valve group (3) comprises a plurality of hydrogen tanks connected in parallel; a tank outlet compressor bypass pipeline (5) is also connected to the input end and the output end of the tank outlet compressor (4), and the tank outlet compressor bypass pipeline (5) comprises a bypass regulating valve (51) and a bypass check valve (52) connected in series.

2. The green hydrogen supply system with a hydrogen storage branch according to claim 1, It is characterized in that The bypass regulating valve (51) is located on a side close to the input end of the storage tank outlet compressor (4), and the bypass check valve (52) is located on a side close to the output end of the storage tank outlet compressor (4).

3. The green hydrogen supply system with a hydrogen storage branch according to claim 1, It is characterized in that The hydrogen production unit (1) is a renewable energy hydrogen production unit, and the hydrogen production unit (1) is connected to a renewable energy power generation system, and the renewable energy power generation system is a wind power generation system, a photovoltaic power generation system and / or a power generation system combining wind power generation and photovoltaic power generation.

4. The green hydrogen supply system with a hydrogen storage branch according to claim 1, It is characterized in that Each hydrogen storage tank is equipped with an attached valve.

5. The green hydrogen supply system with a hydrogen storage branch according to claim 1, It is characterized in that The bypass check valve (52) is a one-way valve that conducts in the direction from the output end to the input end of the tank outlet compressor (4); and / or, the tank outlet compressor (4) is a compressor with flow regulation capability.

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