Hydrogen blending device for low flow rate range

Abstract

The utility model discloses a low flow range hydrogen blending device, including hydrogen pipeline, hydrogen flow regulating valve, natural gas pipeline no.

Description

Technical Field

[0001] This utility model relates to a hydrogen doping device in a low flow range. Background Technology

[0002] Hydrogen blending technology in natural gas pipelines refers to the use of existing natural gas transmission and distribution pipeline systems to partially blend hydrogen with natural gas, producing hydrogen-blended natural gas that is then transported to downstream users, thereby enabling large-scale, low-cost, long-distance hydrogen transportation. Urban gas pipeline blending is a crucial application scenario for this technology and an indispensable end-point. Urban gas transmission and distribution systems exhibit fluctuating gas consumption patterns over a wide range, with higher consumption loads in the morning, afternoon, and evening, and lower consumption at other times. This is particularly true for certain industrial and commercial scenarios with a single end-user, where gas consumption can approach zero during off-peak hours, while peak hours can see consumption reaching tens of thousands of cubic meters per hour. Therefore, achieving stable hydrogen blending across a wide flow range is crucial for urban gas pipeline blending.

[0003] However, due to limitations in the operating range and machining accuracy of the control valves, precise hydrogen blending across both high and low flow rates cannot be achieved simultaneously. Precise hydrogen blending, especially at low flow rates and low blending ratios, is often impossible due to the limitations in the machining accuracy of the flow control valves. A common solution is to add a buffer tank after the hydrogen blender. By monitoring the pressure in the buffer tank, the activation of the hydrogen blender is controlled, thereby increasing the minimum output flow rate of the blender.

[0004] Patent CN202311117082.3 designs a method and system for controlling the hydrogen blending ratio in natural gas pipelines, which can obtain hydrogen-blended natural gas with the required blending ratio by controlling the flow rates of hydrogen and natural gas. However, this patent does not consider the mismatch between the operating range of the gas flow control valve and the large fluctuation range of downstream gas consumption. Patents CN202411417085.3 and CN202411417088.7 design a multi-parallel hydrogen and natural gas inlet pipeline for the hydrogen blending machine, which achieves precise hydrogen blending in both high and low flow ranges by connecting pipelines with different flow sizes in parallel. This method can solve the problem of precise hydrogen blending over a wide flow range to some extent. Currently, the hydrogen blending ratio in the blending process is generally 5-20%, and the flow rate of the hydrogen path is relatively small. Furthermore, hydrogen is a new medium for existing urban gas transmission and distribution systems. To avoid excessive impact on existing urban gas transmission and distribution systems, precise flow control technology for hydrogen at low flow rates is particularly important. However, due to limitations in processing technology, the control accuracy of hydrogen flow control valves used in industry is limited, especially under high pressure (greater than 4MPa) conditions, where the accuracy for the hydrogen inlet line is often only as low as 1m. 3The output flow rate is [number] h. Meanwhile, due to changes in downstream demand, frequent adjustments to the hydrogen flow control valves are necessary, which may further reduce the accuracy of the flow control valves after prolonged operation. Furthermore, the lower the flow rate at the hydrogen blender's outlet, the more frequent the buffer tank starts and stops, increasing the demand for faster response times for the hydrogen and natural gas flow control valves, and consequently, higher equipment investment and operating costs.

[0005] Therefore, existing technologies still need to be improved and developed. Utility Model Content

[0006] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a hydrogen doping device with a low flow range, which aims to solve the problem that the accuracy of the flow control valve is reduced due to frequent operation of the existing hydrogen flow control valve.

[0007] The technical solution of this utility model is as follows:

[0008] A low-flow-range hydrogen blending device includes a hydrogen pipeline, a hydrogen flow regulating valve, a first natural gas pipeline, a first natural gas flow regulating valve, a first hydrogen blender, a first buffer tank, a second hydrogen-blended natural gas flow regulating valve, a second natural gas pipeline, a second natural gas flow regulating valve, a second hydrogen blender, a second buffer tank, and a second hydrogen-blended natural gas pipeline.

[0009] The inlet of the buffer tank is connected to the outlet of the hydrogen blender, and the outlet of the buffer tank is connected to the hydrogen-blended natural gas flow regulating valve.

[0010] The hydrogen blender is equipped with an inlet 1 and an inlet 2. Inlet 1 is connected to a hydrogen pipeline, and inlet 2 is connected to a natural gas pipeline.

[0011] The hydrogen flow regulating valve is located between the hydrogen pipeline and the first inlet, and the natural gas flow regulating valve is located between the first natural gas pipeline and the second inlet.

[0012] The hydrogen blending machine 2 is provided with an air inlet 3 and an air inlet 4. The air inlet 3 is connected to the natural gas pipeline 2, and the natural gas flow regulating valve 2 is connected between the air inlet 3 and the natural gas pipeline 2. The air inlet 4 is connected to the hydrogen-blended natural gas flow regulating valve. The air inlet of the buffer tank 2 is connected to the air outlet of the hydrogen blending machine 2, and the hydrogen-blended natural gas pipeline 2 is connected to the air outlet of the buffer tank 2.

[0013] Optionally, the low-flow-range hydrogen doping device further includes a ball valve.

[0014] The ball valve is connected between the fourth air inlet and the hydrogen-blended natural gas flow regulating valve, and is used to open and close the fourth air inlet.

[0015] Optionally, the low-flow-range hydrogen blending device further includes a hydrogen-blended natural gas pipeline three located between the hydrogen-blended natural gas flow regulating valve and the ball valve one, wherein the hydrogen-blended natural gas pipeline three is equipped with a ball valve two for opening and closing the hydrogen-blended natural gas pipeline three.

[0016] Optionally, the low-flow-range hydrogen blending device further includes a ball valve three located between the hydrogen pipeline and the hydrogen flow regulating valve, the ball valve three being used to open and close the hydrogen pipeline.

[0017] Optionally, the low-flow-range hydrogen blending device further includes a ball valve four located between the natural gas pipeline one and the natural gas flow regulating valve one, the ball valve four being used to open and close the natural gas pipeline one.

[0018] Optionally, the low-flow-range hydrogen blending device further includes a ball valve five located between the natural gas pipeline two and the natural gas flow regulating valve two, the ball valve five being used to open and close the natural gas pipeline two.

[0019] Optionally, the low-flow-range hydrogen blending device further includes a ball valve six located between the buffer tank one and the hydrogen-blended natural gas flow regulating valve, the ball valve six being used to open and close the buffer tank one.

[0020] Optionally, in one embodiment, a high-flow-rate hydrogen pipeline and a regulating valve are connected in parallel between the hydrogen pipeline and the hydrogen flow regulating valve.

[0021] A high-flow-rate natural gas pipeline and a regulating valve are connected in parallel between the natural gas pipeline and the natural gas flow regulating valve.

[0022] A high-flow-rate natural gas pipeline and a regulating valve are connected in parallel between the second natural gas pipeline and the second natural gas flow regulating valve.

[0023] Beneficial effects: This utility model proposes a hydrogen blending device for a low flow range. By setting up a two-stage hydrogen blending system (two hydrogen blenders), it is possible to adjust the hydrogen blended natural gas to a smaller hydrogen blending ratio, or to shut down one of the hydrogen blenders when necessary, thereby meeting the user's needs for different hydrogen blending ratios. Due to the ingenious structural design, it avoids frequent adjustments to the hydrogen flow regulating valve in the hydrogen pipeline and also appropriately avoids the problem of low flow rate at the outlet of the hydrogen blender, thus improving the stability of the system in the low flow range. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the low-flow-range hydrogen doping device of Embodiment 1 of this utility model.

[0026] Figure 2 This is a schematic diagram of the low-flow-range hydrogen doping device of Embodiment 2 of this utility model. Detailed Implementation

[0027] This utility model provides a hydrogen doping device in a low flow range. To make the technical problem to be solved, the technical solution, and the beneficial effects of this application clearer, the following describes this application in further detail with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0028] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0029] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0030] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0031] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0032] This embodiment provides a low-flow-range hydrogen blending device, including a hydrogen pipeline 1, a hydrogen flow regulating valve 2, a first natural gas pipeline 3, a first natural gas flow regulating valve 4, a first hydrogen blender 5, a first buffer tank 6, a second hydrogen-blended natural gas flow regulating valve 7, a second natural gas pipeline 8, a second natural gas flow regulating valve 9, a second hydrogen blender 10, a second buffer tank 12, and a second hydrogen-blended natural gas pipeline 13.

[0033] The inlet of the buffer tank 6 is connected to the outlet of the hydrogen blender 5, and the outlet of the buffer tank 6 is connected to the hydrogen-blended natural gas flow regulating valve 7.

[0034] The hydrogen blender 5 is equipped with an inlet 5-1 and an inlet 5-2. The inlet 5-1 is connected to hydrogen pipeline 1, and the inlet 5-2 is connected to natural gas pipeline 3.

[0035] The hydrogen flow regulating valve 2 is located between the hydrogen pipeline 1 and the inlet 5-1, and the natural gas flow regulating valve 4 is located between the natural gas pipeline 3 and the inlet 5-2.

[0036] The hydrogen blending machine 2 10 is provided with an air inlet 3 10-1 and an air inlet 4 10-2. The air inlet 3 10-1 is connected to the natural gas pipeline 2 8. The natural gas flow regulating valve 2 9 is connected between the air inlet 3 10-1 and the natural gas pipeline 2 8. The air inlet 4 10-2 is connected to the hydrogen-blended natural gas flow regulating valve 7. The air inlet of the buffer tank 2 12 is connected to the air outlet of the hydrogen blending machine 2 10. The hydrogen-blended natural gas pipeline 2 13 is connected to the air outlet of the buffer tank 2 12.

[0037] In this embodiment, by controlling the hydrogen flow regulating valve 2 and the natural gas flow regulating valve 4, a certain hydrogen blending ratio, such as 10%, can be obtained in the hydrogen blender 5 and the buffer tank 6. The hydrogen blended natural gas exiting from the hydrogen blending natural gas flow regulating valve 7 also has a certain hydrogen blending ratio, such as 10%. Further control of the hydrogen blending natural gas flow regulating valve 7 and the natural gas flow regulating valve 9 controls the hydrogen blending ratio of the natural gas entering the hydrogen blender 10 and the buffer tank 12, making it lower than the hydrogen blending ratio in the buffer tank 6, for example, below 10%. This embodiment, by setting a two-step hydrogen blending process, avoids frequent adjustments to the hydrogen flow regulating valve 2, thus improving the stability of the device in the low flow range. Due to the buffer tank 6, the flow rate of the hydrogen pipeline can be guaranteed to be greater than the minimum accuracy value of existing hydrogen regulating valves on the market.

[0038] The operation steps in this embodiment are as follows:

[0039] When a hydrogen blending ratio of less than 10% is required for the hydrogen-blended natural gas, the flow ratio of hydrogen to natural gas at the inlet 5-1 and inlet 5-2 of the hydrogen blender 5 is set to 1:9. After passing through the hydrogen blender 5, a hydrogen-blended natural gas with a hydrogen blending ratio of 10% can be obtained in the buffer tank 6.

[0040] The opening and closing of the hydrogen flow regulating valve 2 and the natural gas flow regulating valve 4, which are connected to the inlet 5-1 and inlet 5-2 of the hydrogen blender 5, are controlled according to the pressure of the buffer tank 6.

[0041] The hydrogen-blended natural gas from the outlet of buffer tank 6 and the natural gas from natural gas pipeline 8 are both fed into hydrogen blender 10. The flow rate of natural gas pipeline 8 is controlled by natural gas flow regulating valve 9 according to the required hydrogen blending ratio, ultimately obtaining hydrogen-blended natural gas that meets the requirements in hydrogen blender 10.

[0042] The buffer tank 2 12 can be used to store hydrogen-blended natural gas with a certain required hydrogen blending ratio, thereby ensuring the stability of the hydrogen blending ratio of the hydrogen-blended natural gas coming out of the hydrogen-blended natural gas pipeline 2 13 connected to the outlet of the buffer tank 2 12.

[0043] The opening and closing of the hydrogen-blended natural gas flow regulating valve 7 and the natural gas flow regulating valve 9 at the outlet of buffer tank 12 are controlled according to the pressure of buffer tank 12.

[0044] In one embodiment, the low-flow-range hydrogen doping device further includes a ball valve 18.

[0045] The ball valve 18 is connected between the air inlet 4 10-2 and the hydrogen-blended natural gas flow regulating valve 7, and is used to open and close the air inlet 4 10-2.

[0046] In one embodiment, the low-flow-range hydrogen blending device further includes a hydrogen-blended natural gas pipeline 20 located between the hydrogen-blended natural gas flow regulating valve 7 and the ball valve 18, wherein the hydrogen-blended natural gas pipeline 20 is provided with a ball valve 2 19 for opening and closing the hydrogen-blended natural gas pipeline 20.

[0047] In one embodiment, the low-flow-range hydrogen blending device further includes a ball valve 14 disposed between the hydrogen pipeline 1 and the hydrogen flow regulating valve 2, the ball valve 14 being used to open and close the hydrogen pipeline 1.

[0048] In one embodiment, the low-flow-range hydrogen blending device further includes a ball valve 15 located between the natural gas pipeline 3 and the natural gas flow regulating valve 4, the ball valve 15 being used to open and close the natural gas pipeline 3.

[0049] In one embodiment, the low-flow-range hydrogen blending device further includes a ball valve 16 located between natural gas pipeline 28 and natural gas flow regulating valve 29, the ball valve 16 being used to open and close the natural gas pipeline 28.

[0050] In one embodiment, the low-flow-range hydrogen blending device further includes a ball valve 17 disposed between the buffer tank 6 and the hydrogen-blended natural gas flow regulating valve 7, the ball valve 17 being used to open and close the buffer tank 6.

[0051] In one embodiment, a high-flow hydrogen pipeline and a regulating valve 21 are connected in parallel between the hydrogen pipeline 1 and the hydrogen flow regulating valve 2.

[0052] A high-flow natural gas pipeline and regulating valve 22 are connected in parallel between the natural gas pipeline 3 and the natural gas flow regulating valve 4.

[0053] A high-flow-rate natural gas pipeline and regulating valve 23 are connected in parallel between the natural gas pipeline 28 and the natural gas flow regulating valve 29.

[0054] The present invention will be further described below with reference to specific embodiments.

[0055] Example 1

[0056] like Figure 1 As shown, the low-flow-range hydrogen blending device of this embodiment includes a hydrogen pipeline 1, a hydrogen flow regulating valve 2, a first natural gas pipeline 3, a first natural gas flow regulating valve 4, a first hydrogen blender 5, a first buffer tank 6, a second hydrogen-blended natural gas flow regulating valve 7, a second natural gas pipeline 8, a second natural gas flow regulating valve 9, a second hydrogen blender 10, a second buffer tank 12, and a second hydrogen-blended natural gas pipeline 13.

[0057] The inlet of the buffer tank 6 is connected to the outlet of the hydrogen blender 5, and the outlet of the buffer tank 6 is connected to the hydrogen-blended natural gas flow regulating valve 7.

[0058] The hydrogen blender 5 is equipped with an inlet 5-1 and an inlet 5-2. The inlet 5-1 is connected to hydrogen pipeline 1, and the inlet 5-2 is connected to natural gas pipeline 3.

[0059] The hydrogen flow regulating valve 2 is located between the hydrogen pipeline 1 and the inlet 5-1, and the natural gas flow regulating valve 4 is located between the natural gas pipeline 3 and the inlet 5-2.

[0060] The hydrogen blending machine 2 10 is provided with an air inlet 3 10-1 and an air inlet 4 10-2. The air inlet 3 10-1 is connected to the natural gas pipeline 2 8. The natural gas flow regulating valve 2 9 is connected between the air inlet 3 10-1 and the natural gas pipeline 2 8. The air inlet 4 10-2 is connected to the hydrogen-blended natural gas flow regulating valve 7. The air inlet of the buffer tank 2 12 is connected to the air outlet of the hydrogen blending machine 2 10. The hydrogen-blended natural gas pipeline 2 13 is connected to the air outlet of the buffer tank 2 12.

[0061] The buffer tank 2 12 can be used to store hydrogen-blended natural gas with a certain required hydrogen blending ratio, thereby ensuring the stability of the hydrogen blending ratio of the hydrogen-blended natural gas coming out of the hydrogen-blended natural gas pipeline 2 13 connected to the outlet of the buffer tank 2 12, and thus stably delivering it to the end user.

[0062] The low-flow-range hydrogen doping device also includes a ball valve 18.

[0063] The ball valve 18 is connected between the air inlet 4 10-2 and the hydrogen-blended natural gas flow regulating valve 7, and is used to open and close the air inlet 4 10-2.

[0064] The low-flow-range hydrogen blending device also includes a hydrogen-blended natural gas pipeline 20 located between the hydrogen-blended natural gas flow regulating valve 7 and the ball valve 18, and the hydrogen-blended natural gas pipeline 20 is equipped with a ball valve 2 19 for opening and closing the hydrogen-blended natural gas pipeline 20.

[0065] The low-flow-range hydrogen blending device also includes a ball valve 14 located between the hydrogen pipeline 1 and the hydrogen flow regulating valve 2, the ball valve 14 being used to open and close the hydrogen pipeline 1.

[0066] The low-flow-range hydrogen blending device also includes a ball valve 15 located between the natural gas pipeline 3 and the natural gas flow regulating valve 4, the ball valve 15 being used to open and close the natural gas pipeline 3.

[0067] The low-flow-range hydrogen blending device also includes a ball valve 16 located between natural gas pipeline 28 and natural gas flow regulating valve 29, the ball valve 16 being used to open and close the natural gas pipeline 28.

[0068] The low-flow-range hydrogen blending device also includes a ball valve 17 located between the buffer tank 6 and the hydrogen-blended natural gas flow regulating valve 7, the ball valve 17 being used to open and close the buffer tank 6.

[0069] It should be noted that hydrogen-blended natural gas pipeline 3.20 and hydrogen-blended natural gas pipeline 2.13 are connected to end users.

[0070] It should be noted that the low-flow-range hydrogen blending device is also connected to the PLC control cabinet, and pressure detectors are also installed on buffer tank 6 and buffer tank 12.

[0071] When the gas consumption of end users is low, such as when there are only a few industrial and commercial users, and the required hydrogen blending ratio is less than 10%, the pressure of hydrogen-blended natural gas is 2.5 MPa.

[0072] In this case, hydrogen blender 1 (5) and hydrogen blender 2 (10) can be operated simultaneously. Ball valve 5 (16) and ball valve 1 (18) can be opened, while ball valve 2 (19) can be closed. The opening of hydrogen flow regulating valve 2 can be set to keep the hydrogen flow rate constant, for example, 1 m³ / s. 3 / h, set the opening of natural gas flow regulating valve 29 to keep the natural gas flow rate constant, for example, 9m³ / h. 3 / h. When the pressure in buffer tank 6 is below a certain value, such as below 2.5 MPa, ball valve 14 and ball valve 15 are opened; when the pressure in buffer tank 6 is above a certain value, such as above 3 MPa, ball valve 14 and ball valve 15 are closed. In this way, hydrogen-blended natural gas with a certain hydrogen blending ratio, such as 10%, can be obtained from hydrogen-blended natural gas pipeline 13.

[0073] By controlling the opening degrees of hydrogen-blended natural gas flow regulating valve 7 and natural gas flow regulating valve 9 according to the gas demand of the end user, the required hydrogen blending ratio can be achieved by controlling the flow ratio of the two channels. For example, setting the flow ratio of the two channels to 1:4 will result in a 5% hydrogen blending ratio. When the pressure of buffer tank 2 12 is lower than 2.5 MPa, ball valves 6 17 and 5 16 are opened; when the pressure of buffer tank 2 12 is higher than 3 MPa, ball valves 6 17 and 5 16 are closed.

[0074] Alternatively, depending on user needs, such as when the terminal requires a hydrogen blending ratio of 10% or higher, the gas consumption demand is lower, and the pressure of the hydrogen-blended natural gas is 2.5 MPa, only hydrogen blender 5 can be turned on, ball valve 5 16 and ball valve 18 can be closed, and ball valve 2 19 can be turned on. The opening of hydrogen flow regulating valve 2 and natural gas flow regulating valve 4 can be controlled according to the gas consumption demand of the terminal user to ensure that the hydrogen-blended natural gas from hydrogen blender 5 meets the requirements.

[0075] It should be noted that the hydrogen flow regulating valve 2, natural gas flow regulating valve 1 4, and natural gas flow regulating valve 2 9 mentioned above are all regulating valves adapted to low flow ranges.

[0076] Example 2

[0077] like Figure 2 As shown, this is to meet the needs of situations where gas consumption fluctuates greatly, that is, situations where gas consumption is sometimes low and sometimes high:

[0078] A high-flow hydrogen pipeline and regulating valve 21 are connected in parallel between hydrogen pipeline 1 and hydrogen flow regulating valve 2;

[0079] A high-flow natural gas pipeline and regulating valve 22 are connected in parallel between the natural gas pipeline 3 and the natural gas flow regulating valve 4.

[0080] A high-flow-rate natural gas pipeline and regulating valve 23 are connected in parallel between the natural gas pipeline 28 and the natural gas flow regulating valve 29.

[0081] When a higher flow rate is required, simply switch to a high-flow pipeline.

[0082] It should be understood that the application of this utility model is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A hydrogen-blending device for low flow rate ranges, characterized in that, This includes a hydrogen pipeline (1), a hydrogen flow regulating valve (2), a natural gas pipeline (3), a natural gas flow regulating valve (4), a hydrogen blending machine (5), a buffer tank (6), a hydrogen-blended natural gas flow regulating valve (7), a natural gas pipeline (8), a natural gas flow regulating valve (9), a hydrogen blending machine (10), a buffer tank (12), and a hydrogen-blended natural gas pipeline (13). The inlet of the buffer tank (6) is connected to the outlet of the hydrogen blender (5), and the outlet of the buffer tank (6) is connected to the hydrogen-blended natural gas flow regulating valve (7). The hydrogen blender (5) is provided with an air inlet (5-1) and an air inlet (5-2). The air inlet (5-1) is connected to the hydrogen pipeline (1), and the air inlet (5-2) is connected to the natural gas pipeline (3). The hydrogen flow regulating valve (2) is located between the hydrogen pipeline (1) and the first inlet (5-1), and the natural gas flow regulating valve (4) is located between the first natural gas pipeline (3) and the second inlet (5-2). The hydrogen blending machine 2 (10) is provided with an air inlet 3 (10-1) and an air inlet 4 (10-2). The air inlet 3 (10-1) is connected to the natural gas pipeline 2 (8). The natural gas flow regulating valve 2 (9) is connected between the air inlet 3 (10-1) and the natural gas pipeline 2 (8). The air inlet 4 (10-2) is connected to the hydrogen-blended natural gas flow regulating valve (7). The air inlet of the buffer tank 2 (12) is connected to the air outlet of the hydrogen blending machine 2 (10). The hydrogen-blended natural gas pipeline 2 (13) is connected to the air outlet of the buffer tank 2 (12).

2. The low-flow-range hydrogen doping device according to claim 1, characterized in that, The low-flow-range hydrogen doping device also includes a ball valve (18). The ball valve (18) is connected between the inlet four (10-2) and the hydrogen-blended natural gas flow regulating valve (7) and is used to open and close the inlet four (10-2).

3. The low-flow-range hydrogen doping device according to claim 1, characterized in that, The low-flow-range hydrogen blending device also includes a hydrogen-blended natural gas pipeline three (20) located between the hydrogen-blended natural gas flow regulating valve (7) and ball valve one (18), and the hydrogen-blended natural gas pipeline three (20) is provided with a ball valve two (19) for opening and closing the hydrogen-blended natural gas pipeline three (20).

4. A low-flow-range hydrogen doping device according to claim 1, characterized in that, The low-flow-range hydrogen doping device also includes a ball valve three (14) located between the hydrogen pipeline (1) and the hydrogen flow regulating valve (2).

5. A low-flow-range hydrogen doping device according to claim 1, characterized in that, The low-flow-range hydrogen blending device also includes a ball valve four (15) located between the natural gas pipeline one (3) and the natural gas flow regulating valve one (4).

6. A low-flow-range hydrogen doping device according to claim 1, characterized in that, The low-flow-range hydrogen blending device also includes a ball valve five (16) located between natural gas pipeline two (8) and natural gas flow regulating valve two (9).

7. A low-flow-range hydrogen doping device according to claim 1, characterized in that, The low-flow-range hydrogen blending device also includes a ball valve six (17) located between the buffer tank (6) and the hydrogen-blended natural gas flow regulating valve (7).

8. A low flow range hydrogen blending device according to claim 1 wherein, A high-flow hydrogen pipeline and regulating valve (21) are connected in parallel between the hydrogen pipeline (1) and the hydrogen flow regulating valve (2); A high-flow natural gas pipeline and a regulating valve (22) are connected in parallel between the natural gas pipeline (3) and the natural gas flow regulating valve (4); A high-flow natural gas pipeline and a regulating valve (23) are connected in parallel between the second natural gas pipeline (8) and the second natural gas flow regulating valve (9).

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