Hydrogen-doped natural gas mixing device and mixing method

Abstract

The application discloses a natural gas hydrogen mixing device and a mixing method. The mixing device comprises a mixing tank, a natural gas pipeline, a hydrogen pipeline and an outlet pipeline. The natural gas pipeline and the hydrogen pipeline are both communicated with the mixing tank. The hydrogen pipeline enters from the bottom of the mixing tank. The outlet pipeline is located at the outlet of the mixing tank. A plurality of elastic small balls are arranged in the mixing tank. The elastic small balls can bounce in the mixing tank. The elastic small balls are arranged in the mixing tank. The elastic small balls bounce in the mixing tank. The elastic small balls can stir the gas in the tank, so that the natural gas and the hydrogen can be uniformly mixed. Due to the elasticity of the elastic small balls, the elastic small balls will not cause excessive impact on the inner wall of the mixing tank when bouncing in the tank, so as to avoid mechanical damage. Moreover, the mixing is not performed in the pipeline, so that the mixing effect is better.

Description

Technical Field

[0001] This invention relates to the field of natural gas hydrogen blending technology, specifically to a natural gas hydrogen blending device and blending method. Background Technology

[0002] Hydrogen blending in long-distance natural gas pipelines has become an effective way to transport hydrogen energy on a large scale and at low cost. In existing pipelines and demonstration projects in China, the hydrogen blending concentration of natural gas has reached as high as 24%. A reasonable and advanced mixing structure is essential to ensure the uniformity of the natural gas and hydrogen blend. Hydrogen and methane have significant differences in properties, especially density; uneven mixing can easily lead to stratification, causing localized increases in hydrogen partial pressure and volume fraction within the pipeline, which can then lead to pipeline failure and leaks. To reduce the safety risks of hydrogen-blended natural gas pipelines, it is necessary to thoroughly mix natural gas and hydrogen.

[0003] Natural gas blending technology has been commercially applied abroad. Currently, there are two main methods for blending hydrogen and natural gas in pipeline transportation: one is to directly inject hydrogen into the natural gas pipeline without any blending equipment; the other is to use a mixing structure or device to thoroughly mix natural gas and hydrogen. For the blending method without a mixing structure or device, literature research shows that under low-flow-rate pipeline conditions, natural gas and hydrogen need to travel a distance of approximately 4000 times the pipeline diameter to achieve uniform mixing. For long-distance pipelines with higher flow rates, a distance of at least 100 times the pipeline diameter is required to achieve uniform mixing, and under certain extreme conditions, the mixing uniformity cannot exceed 95%. Therefore, setting up a mixing structure or device is more beneficial for the mixing of hydrogen and natural gas. In China, the technology for achieving natural gas blending with hydrogen using a mixing structure or device is still in the experimental verification stage, and the methods for blending natural gas with hydrogen are still in the exploratory stage. Typical blending structures include mechanical stirrers and jet mixers, but these methods still have problems such as uneven mixing, excessive impact during mixing, and potential mechanical damage to the pipeline itself.

[0004] Therefore, this patent application is filed. Summary of the Invention

[0005] The purpose of this invention is to provide a natural gas-hydrogen blending device and a corresponding blending method. By using an elastic ball to repeatedly bounce and agitate the gas in the blending tank, the invention solves the technical problems of uneven mixing of natural gas and hydrogen and excessive impact that causes mechanical damage to the pipeline itself.

[0006] This invention is achieved through the following technical solution:

[0007] The first objective of this invention is to provide a natural gas-hydrogen blending device, comprising a blending tank, a natural gas pipeline, a hydrogen pipeline, and an outlet pipeline, wherein the natural gas pipeline and the hydrogen pipeline are both connected to the blending tank, the hydrogen pipeline enters from the bottom of the blending tank, the outlet pipeline is located at the outlet of the blending tank, and the blending tank contains a plurality of elastic balls that can bounce within the blending tank.

[0008] This invention utilizes elastic balls placed inside a mixing tank. These balls bounce within the tank, agitating the gas and achieving efficient and uniform mixing of natural gas and hydrogen. Due to the elasticity of the balls, the bouncing motion prevents excessive impact on the tank's inner wall, thus avoiding mechanical damage. Furthermore, this invention does not perform mixing inside the delivery pipe; instead, the natural gas and hydrogen are mixed directly into the mixing tank, resulting in superior mixing performance.

[0009] As a preferred design, the mixing tank is a conical tank with smaller ends and a larger middle section. The natural gas pipeline is inserted from the top of the mixing tank, and the diameter of the gas inlet at the top of the mixing tank is larger than the diameter of the gas inlet at the bottom.

[0010] In this invention, the mixing tank is designed as a conical tank. This design facilitates the bouncing of the elastic balls within the tank, allowing them to bounce over a wider area and improving the mixing effect. Furthermore, the small diameter of the gas inlet at the bottom of the mixing tank helps the elastic balls accumulate during bouncing, resulting in a greater initial bouncing force when hydrogen enters and a stronger impact force when it exits, thus providing a stronger driving force for the elastic balls and promoting uniform gas mixing.

[0011] As a preferred design, the taper of the mixing tank is 2.

[0012] As a preferred design, the mixing tank has a pressure rating of less than or equal to 10 MPa.

[0013] As a preferred design, both the natural gas pipeline and the hydrogen pipeline have mesh panels at their outlets, and the outlet pipeline also has a mesh panel at its inlet. The mesh openings on the mesh panels have a smaller diameter than the elastic ball. This ensures that the elastic ball will not enter any of the pipelines.

[0014] As a preferred design, the elastic modulus of the elastic ball is 1 to 9.8 MPa, ensuring that the ball has sufficiently good bouncing performance.

[0015] As a preferred design, the elastic ball is a hollow ball, which ensures the elastic ball's bouncing performance while maintaining a light weight.

[0016] As a preferred design, the elastic microsphere is made of thermoplastic elastomer material.

[0017] As a preferred design, the mixing tank is equipped with an emergency pressure relief valve, and the natural gas pipeline, hydrogen pipeline, and gas outlet pipeline are all equipped with flow control valves.

[0018] As a preferred design, the air outlet pipe is equipped with a turbulence-inducing element.

[0019] As a preferred design, the turbulence element includes a connecting plate and turbulence plates. One end of each turbulence plate is fixed to the turbulence plate, and the other end is connected to the pipe wall of the exhaust pipe. Multiple turbulence plates are provided on both sides of the connecting plate.

[0020] As a preferred design, the baffle is a semi-circular piece with a baffle hole in the middle, and the included angle between each baffle and the connecting plate is 45°. Multiple baffles located on the same side of the connecting plate are parallel and linearly arranged along the extension direction of the connecting plate.

[0021] In this invention, a flow-disrupting element is installed inside the gas outlet pipe, which helps to further mix the mixed gas.

[0022] The second objective of this invention is to provide a method for blending natural gas with hydrogen, using a hydrogen blending device as described in any of the preceding claims, comprising: using flow control valves to control the amount of natural gas and hydrogen entering the blending tank respectively; controlling the flow control valve in the gas outlet pipe to be in the open state during blending; and ejecting an elastic ball within the blending tank under the action of hydrogen to agitate and mix the gases.

[0023] The advantages and beneficial effects of this invention compared to the prior art are:

[0024] 1. The natural gas-hydrogen blending device provided by this invention utilizes elastic balls placed inside a blending tank. These elastic balls bounce within the tank, agitating the gas and achieving efficient and uniform mixing of natural gas and hydrogen. Due to the elasticity of the balls, the bouncing motion within the tank prevents excessive impact on the inner wall, thus avoiding mechanical damage. Furthermore, this invention does not perform the mixing inside the delivery pipe, but rather introduces the natural gas and hydrogen into the blending tank, resulting in a superior mixing effect.

[0025] 2. The hydrogen-doped mixing method provided by this invention utilizes the bouncing of elastic balls to mix gases. Unlike existing mechanical stirring and jet mixing methods, this method improves mixing efficiency and effect while avoiding excessive impact. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0027] Figure 1 This is a schematic diagram of a natural gas hydrogen blending device provided in Embodiment 1 of the present invention.

[0028] Figure 2 This is a schematic diagram of the taper ratio of the mixing tank of the present invention.

[0029] Figure 3 This is a schematic diagram of a natural gas hydrogen blending device provided in Embodiment 2 of the present invention.

[0030] Figure 4 This is a side view of the turbulence element provided in Embodiment 2 of the present invention.

[0031] Figure 5 This is the front view of the spoiler.

[0032] The markings and the components they represent in the attached diagram are as follows:

[0033] 1-Mixing tank, 2-Natural gas pipeline, 3-Hydrogen pipeline, 4-Outlet gas pipeline, 5-Elastic ball, 6-Mesh plate, 7-Emergency pressure relief valve, 8-Flow control valve, 9-Break current element, 901-Connecting plate, 902-Break current plate, 903-Break current hole, 10-Support. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0035] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. In other embodiments, well-known structures, circuits, materials, or methods have not been specifically described in order to avoid obscuring the invention.

[0036] Throughout this specification, references to "an embodiment," "an example," or "an example" mean that a particular feature, structure, or characteristic described in connection with that embodiment or example is included in at least one embodiment of the invention. Therefore, the phrases "an embodiment," "an example," "an example," or "an example" appearing in various places throughout the specification do not necessarily refer to the same embodiment or example. Furthermore, specific features, structures, or characteristics can be combined in one or more embodiments or examples in any suitable combination and / or sub-combination. Moreover, those skilled in the art will understand that the illustrations provided herein are for illustrative purposes and are not necessarily drawn to scale. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0037] In the description of this invention, the terms "front", "rear", "left", "right", "up", "down", "vertical", "horizontal", "high", "low", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0038] Example 1:

[0039] This embodiment provides a natural gas hydrogen blending device, such as... Figure 1 As shown, the hydrogen blending device includes a blending tank 1, a natural gas pipeline 2, a hydrogen pipeline 3, and an outlet pipeline 4. Both the natural gas pipeline 2 and the hydrogen pipeline 3 are connected to the blending tank 1. The natural gas pipeline 2 is inserted from the top of the blending tank 1, while the hydrogen pipeline 3 enters from the bottom of the blending tank 1. The outlet pipeline 4 is located at the outlet of the blending tank 1, and the outlet of the blending tank 1 is on its side. There are multiple elastic balls 5 inside the blending tank 1, and the elastic balls 5 can bounce inside the blending tank 1.

[0040] Natural gas flows into the buffer mixing tank 1 from the top through natural gas pipeline 2, while hydrogen flows into the buffer mixing tank 1 from the bottom through hydrogen pipeline 3. The mixed hydrogen-blended natural gas flows out from the outlet pipeline 4. The elastic balls 5 have a certain weight and initially accumulate at the bottom of the mixing tank 1. Hydrogen enters from the bottom of the hydrogen mixing tank, and the hydrogen blows the elastic balls 5 upwards, causing them to bounce and repeatedly impact the inner wall of the mixing tank 1. This chaotic trajectory of multiple balls agitates the gas inside the tank, achieving the purpose of mixing the gas. At the same time, the impact of the elastic balls 5 on the mixing tank 1 does not cause mechanical damage.

[0041] To further enhance the performance and ensure that the elastic ball 5 bounces sufficiently and repeatedly within the mixing tank 1, this embodiment designs the mixing tank 1 as a conical tank with smaller ends and a larger middle section. Furthermore, the diameter of the gas inlet at the top of the mixing tank 1 is larger than that at the bottom. This design facilitates the accumulation of the elastic ball 5 at the bottom gas inlet of the mixing tank 1 during its bouncing process, ensuring that the elastic ball 5 is always propelled by hydrogen gas exiting from the bottom as a bouncing aid. Additionally, the smaller diameter of the bottom gas inlet allows for a greater hydrogen impingement, resulting in a stronger pushing force on the elastic ball 5 and promoting uniform gas mixing.

[0042] Preferably, the mixing tank 1 has a taper of 2, and the mixing tank 1 is composed of two symmetrical frustum cones. The taper of the frustum cone is (diameter of the base of the frustum - diameter of the top of the frustum) / height of the frustum. The diameter of the base of the frustum is as follows: Figure 2 R1 represents the diameter of the top of the frustum (equal to the diameter of the natural gas pipeline 2), R2 represents the diameter of the top of the frustum, and H represents the height of the frustum. The pressure of the mixing tank 1 is less than or equal to 10 MPa.

[0043] In this embodiment, the mixing tank 1 is preferably made of stainless steel, and the tapered diameter of the mixing tank 1 is designed to be 2, which is large enough compared to the diameter of each pipe to ensure that hydrogen and natural gas have sufficient space to mix. At the same time, it can also provide sufficient bouncing space for the elastic ball 5, and the tapered diameter of 2 is conducive to the elastic ball 5 being able to bounce on all four side walls. The trajectory of the elastic ball 5 is long enough to cover the entire internal space of the mixing tank 1.

[0044] Even better, the elastic modulus of the elastic sphere 5 is designed to be 1 to 9.8 MPa, the elastic sphere 5 is a hollow sphere, and it is made of thermoplastic elastomer material.

[0045] To prevent the elastic ball 5 from entering the natural gas pipeline 2, the hydrogen pipeline 3, and the gas outlet pipeline 4, a mesh plate 6 is provided at the gas outlet of the natural gas pipeline 2 and the hydrogen pipeline 3, and at the gas inlet of the gas outlet pipeline 4. The mesh aperture of the mesh plate 6 is smaller than the diameter of the elastic ball 5.

[0046] An emergency pressure relief valve 7 is also provided on the mixing tank 1 to prevent emergency pressure relief when the tank pressure is too high. Flow control valves 8 are provided in the natural gas pipeline 2, hydrogen pipeline 3, and gas outlet pipeline 4. The mixing of hydrogen-blended natural gas with different hydrogen blending ratios can be achieved by adjusting the valve opening.

[0047] Example 2:

[0048] Based on Example 1, such as Figure 3 , 4As shown in the figure, a flow-dispersing element 9 is provided inside the gas outlet pipe 4. Specifically, the flow-dispersing element 9 includes a connecting plate 901 and flow-dispersing plates 902. One end of each flow-dispersing plate 902 is fixed to the flow-dispersing plate, and the other end is connected to the pipe wall of the gas outlet pipe 4. Multiple flow-dispersing plates 902 are provided on both sides of the connecting plate 901. The flow-dispersing plates 902 on the same side have a certain spacing, and the flow-dispersing plates 902 on the same side of the connecting plate 901 are arranged on the connecting plate 901. They can be arranged along the length or width direction of the connecting plate 901, or they can be arranged in an array on the connecting plate 901. In this embodiment, the schematic diagram in the figure shows that they are arranged linearly along the length direction of the connecting plate 901, and the flow-dispersing plates on the same side are parallel to each other. The flow-dispersing plates located in the gas outlet pipe 4 can further disturb the flowing mixed gas, thereby further mixing and significantly improving the mixing degree of natural gas and hydrogen.

[0049] Better yet, this embodiment further defines the specific structure of the spoiler 902. However, it can also be designed with other structures in other embodiments, which will not be described in detail here, as long as it can achieve a better spoiling effect.

[0050] In this embodiment, the baffle plate 902 is designed as a semi-circular piece with a baffle hole 903 in the middle, and the included angle between each baffle plate 902 and the connecting plate 901 is 45°.

[0051] In this invention, four supports 10 are also provided at equal intervals at the bottom of the mixing tank 1 to ensure the stability of the mixing tank 1.

[0052] The method of blending using the above-mentioned natural gas hydrogen blending device includes:

[0053] The flow control valves on the natural gas pipeline and the hydrogen pipeline respectively control the amount of natural gas and hydrogen entering the blending tank. When the natural gas and hydrogen enter blending tank 1, they undergo initial mixing due to their density difference. An elastic ball 5 is blown at the inlet of the hydrogen pipeline 3 and reciprocates against the inner wall of blending tank 1. When the elastic ball 5 falls back to the bottom of blending tank 1, it slides to the inlet of the hydrogen pipeline 3 and continues its reciprocating motion under the impact of the hydrogen. This cycle of multiple elastic balls 5 ensures thorough mixing of the hydrogen and natural gas. The mixed gas flows to the outlet pipeline 4, where it is further mixed by the turbulence of the flow-dispersing element 9 until it flows out for subsequent processes. During the blending process, the flow control valve on the outlet pipeline is open and closed when maintenance is required.

[0054] At the same time, the amount of natural gas fed into the mixing tank per unit time is controlled to be less than the amount of hydrogen fed into the mixing tank. In this way, the impact force of hydrogen rushing out of the hydrogen pipeline 3 is greater than that of natural gas, which impacts the elastic ball 5 and allows the hydrogen to rise rapidly and mix with the natural gas. The hydrogen then rushes into the natural gas area using its own impact force.

[0055] The natural gas-hydrogen blending device provided by this invention mixes natural gas and hydrogen in a buffer blending tank 1, which solves the problem of excessive mixing impact that may cause mechanical damage to the pipeline itself. The elastic spheres 5 ensure thorough mixing of natural gas and hydrogen, improving mixing uniformity. The flow-disrupting element 9 further enhances the mixing uniformity of natural gas and hydrogen.

[0056] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A hydrogen-blended natural gas mixing device, characterized by comprising: The system includes a mixing tank (1), a natural gas pipeline (2), a hydrogen pipeline (3), and an outlet pipeline (4). The natural gas pipeline (2) and the hydrogen pipeline (3) are both connected to the mixing tank (1). The hydrogen pipeline (3) enters from the bottom of the mixing tank (1). The outlet pipeline (4) is located at the outlet of the mixing tank (1). The mixing tank (1) contains a plurality of elastic balls (5), which can bounce inside the mixing tank (1).

2. The hydrogen-blended natural gas mixing device according to claim 1, characterized in that, The mixing tank (1) is a conical tank with small ends and a large middle. The natural gas pipeline (2) is inserted from the top of the mixing tank (1). The diameter of the gas inlet at the top of the mixing tank (1) is larger than the diameter of the gas inlet at the bottom.

3. The hydrogen-blended natural gas mixing device according to claim 2, characterized in that, The taper of the mixing tank (1) is 2.

4. The hydrogen-blended natural gas mixing device according to claim 2, characterized in that, The pressure of the mixing tank (1) is less than or equal to 10 MPa.

5. The hydrogen-blended natural gas mixing device of claim 1, wherein, The gas outlets of the natural gas pipeline (2) and the hydrogen pipeline (3) are provided with mesh plates (6), and the inlet of the gas outlet pipeline (4) is provided with mesh plates (6). The mesh aperture of the mesh plate (6) is smaller than the diameter of the elastic ball (5).

6. The hydrogen-blended natural gas mixing device of claim 1, wherein, The elastic modulus of the elastic ball (5) is 1 to 9.8 MPa.

7. The hydrogen-blended natural gas mixing device of claim 1, wherein, The elastic ball (5) is a hollow ball.

8. The hydrogen-blend device of claim 1, wherein, The elastic sphere (5) is made of thermoplastic elastomer material.

9. The hydrogen-blend device of claim 1, wherein, The mixing tank (1) is equipped with an emergency pressure relief valve (7), and the natural gas pipeline (2), hydrogen pipeline (3), and gas outlet pipeline (4) are all equipped with flow control valves (8).

10. The hydrogen-blend device of any one of claims 1 to 9, wherein, The air outlet pipe (4) is equipped with a turbulence-inducing element (9).

11. The hydrogen-blend device of claim 10, wherein, The turbulence element (9) includes a connecting plate (901) and turbulence plates (902). One end of each turbulence plate (902) is fixed to the turbulence plate, and the other end is connected to the pipe wall of the exhaust pipe (4). Multiple turbulence plates (902) are provided on both sides of the connecting plate (901).

12. The hydrogen-blend device of claim 11, wherein, The baffle (902) is a semi-circular piece with a baffle hole (903) in the middle. The angle between each baffle (902) and the connecting plate (901) is 45°. Multiple baffles (902) located on the same side of the connecting plate (901) are parallel and linearly arranged along the extension direction of the connecting plate (901).

13. The method of claim 1 to 12, wherein, include: The flow control valves are used to control the amount of natural gas and hydrogen entering the mixing tank. During mixing, the flow control valve in the gas outlet pipe is kept open, and the elastic ball is ejected in the mixing tank under the action of hydrogen to agitate and mix the gas.

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