Static mixer for natural gas-hydrogen mixing and mixing system

Abstract

The utility model relates to the technical field of mixed hydrogen conveying of natural gas pipelines, in particular to a static mixer for mixing natural gas and hydrogen, which comprises a mixer body, and a plurality of runner grooves are formed in the outer wall of the mixer body along the radial direction; the adjacent runner grooves are communicated through a plurality of runner holes; a plurality of first air inlet holes and second air inlet holes are formed in the mixer body in the radial direction, and the section shapes of the first air inlet holes and the second air inlet holes are different. Wherein the flow channel groove is used for guiding airflow; the runner holes are used for enabling inlet gas to generate a complex flow field; the first gas inlet hole and the second gas inlet hole can enable gas to generate different turbulent flows and disturbances; the static mixer is of an integrated structure and is simple in structure, low in machining cost, free of other movable parts, low in maintenance cost and easy to install. The problems that in the prior art, a static mixer is complex in structure, high in cost and poor in mixing effect are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the hydrogen mixing conveying technical field of natural gas pipeline, concretely is a kind of static mixer and mixing system for natural gas-hydrogen blending, especially a kind of high-efficiency low-pressure drop static mixer and mixing system for natural gas-hydrogen blending. BACKGROUND

[0002] Under the background of global energy transformation, hydrogen energy is regarded as an important part of future clean energy. Hydrogen blending into natural gas pipeline transportation has become one of the key research directions of current hydrogen energy large-scale application. Hydrogen can be mixed with natural gas and transported using existing natural gas pipeline network, which not only reduces carbon emissions, but also extends the service life of existing natural gas infrastructure and accelerates the popularization of hydrogen energy in terminal markets. Therefore, since 2000, many countries have launched research and pilot work on natural gas hydrogen blending technology, published hydrogen energy development roadmap and invested a large amount of resources in the development and application of hydrogen blending demonstration projects, promoting the progress of hydrogen in production, storage, transportation, distribution and terminal use.

[0003] However, due to the significant difference in physical properties between hydrogen and natural gas, natural gas-hydrogen blending system faces many technical challenges. The density of hydrogen is about one-eighth of that of natural gas, and the hydrogen molecule is smaller and diffuses faster, which leads to the phenomenon of stratification and uneven distribution of hydrogen-natural gas mixture in the pipeline. Especially in the pipeline shutdown or static state, due to the action of gravity, hydrogen tends to float, causing uneven distribution of local volume fraction. This phenomenon can cause potential safety hazards, such as the increase of hydrogen concentration in local area may cause hydrogen embrittlement problem of pipeline material, increasing the risk of pipeline leakage and failure. In addition, uneven gas mixing will also affect the gas quality of terminal users, which may lead to reduced combustion efficiency or other safety problems.

[0004] To solve these problems, a static mixer is usually introduced in the natural gas-hydrogen blending system, and the uniform mixing of hydrogen and natural gas is achieved by reasonably designing the structure of the mixer. The static mixer does not need additional power and can generate turbulence in the flow process by using the gas flow in the pipeline to promote gas mixing. For example, the Chinese utility model patent with the publication number CN220186558U discloses a natural gas hydrogen blending device, which is provided with spiral blades and flow straightening pieces in the inner cavity of the upper part of the long cylindrical mixing element. The flow straightening pieces include horizontal flow straightening plates and vertical flow straightening plates. The horizontal flow straightening plates are arranged horizontally, and the vertical flow straightening plates are arranged vertically. A plurality of first flow straightening holes and second flow straightening holes are arranged in the horizontal flow straightening plates and vertical flow straightening plates, respectively. The vertical flow straightening plates are arranged on the upper and lower sides of the horizontal flow straightening plates. The natural gas and hydrogen are sequentially mixed when flowing through the spiral blades and flow straightening pieces, and the natural gas is uniformly mixed. The Chinese utility model with the publication number CN118925529A discloses a natural gas hydrogen static mixer, which is provided with a gradually expanding section, a flow disturbing section, a mixing section and a mixed gas outlet pipeline. The mixing effect is improved by step-by-step mixing. The gradually expanding section reduces the resistance and increases the static pressure, thereby promoting the mixing of hydrogen and natural gas. However, the above-mentioned mixers have complex structures, high manufacturing costs and difficult maintenance. In the mixing process, the turbulence of the mixed gas at each stage is single, and high-efficiency and effective mixing cannot be achieved. There is still room for improvement in terms of low pressure drop, mixing efficiency and durability. Therefore, it is an important requirement for the development of natural gas-hydrogen blending system technology to develop a static mixer device with simple structure, high efficiency and low maintenance cost to ensure the uniform mixing of hydrogen and natural gas. Utility model content

[0005] In view of the problems of the existing static mixer in the prior art, such as complex structure, high cost and poor mixing effect, the utility model provides a static mixer for natural gas-hydrogen blending and a blending system.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical solutions:

[0007] The utility model provides a static mixer for natural gas-hydrogen blending, which comprises a mixer body, a plurality of flow channel grooves are radially formed in the outer wall of the mixer body, the adjacent flow channel grooves are communicated through a plurality of flow channel holes, a plurality of first gas inlet holes and second gas inlet holes are radially formed in the inner part of the mixer body, and the cross-sectional shapes of the first gas inlet holes and the second gas inlet holes are different.

[0008] Optionally, the flow channel groove is a spiral flow channel groove.

[0009] Optionally, the first gas inlet hole is an elliptical gas inlet hole, and the second gas inlet hole is a circular gas inlet hole.

[0010] Optionally, the first air inlet holes and the second air inlet holes are scattered from the center of the radial section of the mixer body to the edge of the radial section, forming an inner-outer layered structure.

[0011] Optionally, the first air inlet holes include central air inlet holes located at the center of the radial section of the mixer body and outer layer air inlet holes located close to the edge of the radial section of the mixer body and distributed circumferentially outside the central air inlet holes; the second air inlet holes are uniformly distributed between the central air inlet holes and the outer layer air inlet holes.

[0012] Optionally, the number of the first air inlet holes is 3-15, and the number of the second air inlet holes is 4-32.

[0013] Optionally, the length of the mixer body is 200-2000 mm.

[0014] The utility model also provides a kind of for natural gas-hydrogen blending blending system, including natural gas inlet pipeline, hydrogen inlet pipeline, gas collection pipeline and above static mixer;The natural gas inlet pipeline and hydrogen inlet pipeline are connected with gas collection pipeline;The static mixer is arranged in the inside of gas collection pipeline.

[0015] Optionally, the static mixer is installed at 1 / 3 of the distance between the junction of the natural gas inlet pipeline and the hydrogen inlet pipeline and the outlet of the gas collection pipeline.

[0016] Optionally, the natural gas inlet pipeline and the hydrogen inlet pipeline are arranged vertically.

[0017] Compared with the prior art, the utility model has the following beneficial effects:

[0018] The utility model relates to a static mixer for natural gas-hydrogen blending, comprising a mixer body, by setting several flow channel grooves on the outer wall of the mixer body along the radial direction, the gas flow is guided, so that the natural gas and hydrogen flowing along the flow channel groove path, thereby generating turbulent flow and disturbance, increasing the contact time and mixing area of hydrogen and natural gas, the natural gas and hydrogen entering the flow channel groove produce complex flow field through several flow channel holes between adjacent flow channel grooves, further ensuring that the mixing effect of hydrogen-blended natural gas at the outlet reaches high uniformity, by opening several first gas inlets and second gas inlets in the mixer body along the radial direction, and making the cross-sectional shape of the first gas inlet different from that of the second gas inlet, the different shape of the gas inlet continues to play a role when the gas enters the mixer body, different turbulent flow and disturbance are generated, the gas flow path is guided to disperse in multiple directions, this dispersion flow pattern further strengthens the turbulent flow, so that the hydrogen and natural gas are fully mixed in the orifice plate area, thereby greatly improving the mixing uniformity and mixing efficiency of natural gas and hydrogen, at the same time, under the synergistic action of the first gas inlet, the second gas inlet and the flow channel groove, not only can promote the uniform mixing of the gas, but also can minimize the gas flow separation and resistance, has lower pressure drop, and is suitable for stable operation under high pressure for a long time. The static mixer is of integrated structure, simple structure, low processing cost, no other movable parts, low maintenance cost, simple installation, excellent reliability and adaptability.

[0019] The flow channel groove is a spiral flow channel groove. The design of the spiral flow channel groove not only prolongs the contact path of the gas, but also generates centrifugal force during the fluid flow process. The centrifugal force causes the fluid to generate turbulent flow in the groove. The turbulent flow can enhance the momentum exchange and mass transfer between the fluids, reduce the laminar flow phenomenon of the fluids during the mixing process, improve the uniformity of the mixing, and reduce the energy consumption and pressure drop during the gas mixing process.

[0020] The first gas inlet is an elliptical gas inlet, and the second gas inlet is a circular gas inlet. Tests show that the elliptical gas inlet and the circular gas inlet are not only more convenient and simple in processing, but also the major axis direction of the elliptical gas inlet can guide the fluid to flow in a specific direction, and the circular gas inlet provides more uniform fluid distribution. This design helps to form a complex fluid flow pattern at the initial stage of mixing, promoting the full mixing of natural gas and hydrogen.

[0021] The first gas inlet hole and the second gas inlet hole are scattered from the center of the radial section of the mixer body to the edge of the radial section, forming an inner and outer layered structure, through the design of the inner and outer layered structure, the flow path of the fluid in the mixer is optimized, forming a radial and tangential flow pattern, which helps to increase the contact area and interaction opportunities between the fluids, enabling the fluids to more fully fill the internal space of the mixer, avoiding local areas with too high or too low fluid concentration, thereby improving the mixing uniformity.

[0022] The first gas inlet hole includes a center gas inlet hole located at the center of the radial section of the mixer body and an outer layer gas inlet hole located near the edge of the radial section of the mixer body and distributed circumferentially outside the center gas inlet hole; the second gas inlet hole is uniformly distributed between the center gas inlet hole and the outer layer gas inlet hole. The distribution of the center gas inlet hole, the outer layer gas inlet hole and the second gas inlet hole between them enables the gas to form a complex flow path inside the mixer while increasing the contact area and uniformity of interaction between the fluids, thereby improving the mixing efficiency and uniformity.

[0023] The number of the first gas inlet hole is 3-15, and the number of the second gas inlet hole is 4-32. By reasonably designing the number and size of the gas inlet hole, the flow of the fluid can be accurately controlled. Within the range of the number of the first gas inlet hole and the second gas inlet hole, the flow distribution of each gas inlet hole can be more easily adjusted to meet the needs of different mixing ratios.

[0024] The length of the mixer body is 200-2000mm, which can optimize the mixing effect and improve the adaptability and flexibility of the equipment.

[0025] The utility model also provides a kind of for natural gas-hydrogen mixing mixing system, it is characterized in that, including natural gas gas inlet pipeline, hydrogen gas inlet pipeline, gas collection pipeline and above-mentioned static mixer;The natural gas gas inlet pipeline and hydrogen gas inlet pipeline are connected with gas collection pipeline;The static mixer is arranged in the inside of gas collection pipeline. Natural gas and hydrogen are entered gas collection pipeline by respective gas inlet pipeline, and mixing is carried out in the inside of static mixer, and the complex flow path and vortex structure in the inside of static mixer can sufficiently break the laminar state between fluids, promote the sufficient mixing of natural gas and hydrogen. This mixing system has simple structure, low maintenance cost, and good flexibility, high reliability, and has wide application prospect and practical value in the field of natural gas-hydrogen mixing.

[0026] The static mixer is installed at 1 / 3 of the natural gas inlet pipeline and the hydrogen gas inlet pipeline converging point to the gas converging pipeline outlet. The natural gas and the hydrogen gas can be ensured to be fully mixed in the early stage of the mixing process, and the pressure and temperature fluctuations generated in the mixing process of the system are reduced, the safety hidden danger of the system is reduced, and the safety of the system is improved.

[0027] The natural gas inlet pipeline and the hydrogen gas inlet pipeline are vertically arranged. The vertically arranged inlet pipelines can make the natural gas and the hydrogen gas form different flow directions when entering the gas converging pipeline, so that more complex flow patterns and vortex structures are generated inside the static mixer, and the mixing efficiency and uniformity are further improved. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is an axial side structure schematic view of the static mixer for natural gas-hydrogen mixing of the utility model.

[0029] Figure 2 It is the pressure distribution nephogram of the T-shaped hydrogen-doped natural gas pipeline when the main inlet port CH4 inlet velocity is 3m / s and the secondary inlet port H2 inlet velocity is 7m / s for the static mixer for natural gas-hydrogen mixing of the utility model.

[0030] Figure 3 It is the mixing uniformity change graph at different cross sections of the T-shaped hydrogen-doped natural gas pipeline when the main inlet port CH4 inlet velocity is 3m / s and the secondary inlet port H2 inlet velocity is 7m / s for the static mixer for natural gas-hydrogen mixing of the utility model.

[0031] Figure 4 It is the velocity vector graph of the T-shaped hydrogen-doped natural gas pipeline when the main inlet port CH4 inlet velocity is 3m / s and the secondary inlet port H2 inlet velocity is 7m / s for the static mixer for natural gas-hydrogen mixing of the utility model.

[0032] Figure 5 It is the first inlet port and the second inlet port arrangement mode graph of the static mixer for natural gas-hydrogen mixing of the embodiment 2 of the utility model.

[0033] Figure 6 It is the first inlet port and the second inlet port arrangement mode graph of the static mixer for natural gas-hydrogen mixing of the embodiment 3 of the utility model.

[0034] Figure 7 It is the first inlet port and the second inlet port arrangement mode graph of the static mixer for natural gas-hydrogen mixing of the embodiment 4 of the utility model.

[0035] Figure 8The first gas inlet and the second gas inlet arrangement mode diagram of the static mixer for natural gas-hydrogen mixing of the embodiment 5 of the utility model.

[0036] Figure 9 The first gas inlet and the second gas inlet arrangement mode diagram of the static mixer for natural gas-hydrogen mixing of the embodiment 6 of the utility model.

[0037] Figure 10 The first gas inlet and the second gas inlet arrangement mode diagram of the static mixer for natural gas-hydrogen mixing of the embodiment 7 of the utility model.

[0038] Figure 11 The first gas inlet and the second gas inlet arrangement mode diagram of the static mixer for natural gas-hydrogen mixing of the embodiment 8 of the utility model.

[0039] Figure 12 The mixing system structure diagram for natural gas-hydrogen mixing of the utility model.

[0040] Wherein, 1-mixer body, 2-flow channel groove, 3-flow channel hole, 4-first gas inlet hole, 5-second gas inlet hole, 6-natural gas inlet pipeline, 7-hydrogen inlet pipeline, 8-gas collection pipeline, 41-center gas inlet hole, 42-outer layer gas inlet hole. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely below in combination with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. The components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the utility model.

[0043] It should be noted that: similar signs and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0044] In the description of the embodiments of the utility model, it needs to be explained that, if the terms "upper", "lower", "horizontal", "inner" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship of the utility model product when it is usually placed, it is only for the convenience of describing the utility model and simplifying the description, and it does not indicate or imply that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" and the like are only used for differentiation in description, and cannot be understood as indicating or implying relative importance.

[0045] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly inclined. For example, "horizontal" only means that its direction is relatively more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly inclined.

[0046] In the description of the embodiments of the utility model, it also needs to be explained that, unless otherwise explicitly specified and limited, if the terms "set", "install", "connect", "connect" appear, they should be understood in a broad sense, for example, they can be fixedly connected, or they can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0047] The utility model will be further described in detail below in combination with specific embodiments, which is an explanation of the utility model rather than a limitation.

[0048] Referring to Figure 1 The utility model discloses a kind of static mixers for natural gas-hydrogen blending, including mixer body 1, preferably, the length of the mixer body 1 is the length of the mixer body 1 is 200 ~ 2000 mm;Several flow channel grooves 2 are opened along the radial direction in the outer wall of the mixer body 1, preferably, the flow channel groove 2 is spiral flow channel groove, flow channel groove 2 depth is 1 / 10 ~ 1 / 5 of the diameter of the mixer body 1, width is 1 / 9 ~ 1 / 4 of the diameter of the mixer body 1, the pitch of flow channel groove 2 is 100 ~ 300 mm;Several flow channel holes 3 are communicated between adjacent flow channel grooves 2;Several first air inlet holes 4 and second air inlet holes 5 are opened along the radial direction in the mixer body 1, the cross-sectional shape of the first air inlet hole 4 and the second air inlet hole 5 is different.

[0049] In the case of the total cross-sectional area of the intake port being specified, the shapes of the first air hole 4 and the second air hole 5 are made different to produce different disturbances and turbulent flows, promoting gas mixing, without changing the total cross-sectional area of the first air hole 4 and the second air hole 5.

[0050] The static mixer produces a guiding effect on the airflow by arranging a plurality of flow channel grooves 2 radially on the outer wall of the mixer body 1, so that the incoming natural gas and hydrogen flow along the flow channel grooves 2, thereby producing turbulent flow and disturbance, increasing the contact time and mixing area of hydrogen and natural gas; the adjacent flow channel grooves 2 are communicated by a plurality of flow channel holes 3, which can produce a complex flow field of the natural gas and hydrogen entering the flow channel grooves 2, further ensuring that the mixing effect of hydrogen-doped natural gas at the outlet reaches high uniformity; the cross-sectional shapes of the first air hole 4 and the second air hole 5 are different, which can make the different shapes of the air inlet continue to play a role when the gas enters the mixer body, produce different turbulent flow and disturbance, guide the gas flow path to be dispersed in multiple directions, and this dispersed flow pattern further strengthens the turbulent flow, so that the hydrogen and natural gas are fully mixed in the orifice plate area, thereby greatly improving the mixing uniformity and mixing efficiency of the natural gas and hydrogen; at the same time, under the synergistic action of the first air hole 4, the second air hole 5 and the flow channel groove 2, not only can promote the uniform mixing of the gas, but also can minimize the airflow separation and resistance, has lower pressure drop, and is suitable for stable operation under high pressure for a long time. The static mixer is of an integrated structure, simple structure, low processing cost, no other moving parts, low maintenance cost, simple installation, excellent reliability and adaptability.

[0051] Installation and working principle: The mixer is installed in the pipeline after the hydrogen and natural gas junction point, the outer diameter of the mixer body 1 is in contact with the inner wall of the installed pipeline, after installation to the natural gas-hydrogen blending system, the static mixer first produces guiding effect on gas flow through its multi-head spiral flow channel slot 2. Natural gas and hydrogen are forced to flow along the path of flow channel slot 2 when flowing through flow channel slot 2. This rotating flow makes the gas produce turbulent flow and disturbance, increases the contact time and mixing area of hydrogen and natural gas. Under the continuous action of flow channel slot 2, the gas is constantly rolling and mixing, advancing along the direction of the pipeline, thereby realizing the preliminary uniform mixing. The flow channel holes on the spiral groove 2 further strengthen the flow disturbance effect of the gas, so that the gas has high mixing uniformity before entering the orifice plate structure under low pressure drop. When the gas enters the inlet hole, the first inlet hole 4 and the second inlet hole 5 continue to play a role, and the different shapes of the inlet will guide the gas flow path to be dispersed in multiple directions. This dispersed flow pattern further strengthens the turbulent flow, so that hydrogen and natural gas are fully mixed in the orifice plate area. Through the reasonable distribution of flow channel holes 3, the gas forms a complex flow field in the orifice plate structure, ensuring that the mixed hydrogen natural gas reaches high uniformity at the outlet. At the same time, through optimization design, the gas mixing is enhanced while the low pressure drop is maintained, avoiding the burden on the pressure of the pipeline system, thereby realizing stable and energy-saving gas mixing transmission effect.

[0052] See Figure 1The utility model discloses a kind of static mixers for natural gas-hydrogen blending, including mixer body 1, the outer wall of the mixer body 1 is opened with several flow channel grooves 2 along radial direction, the flow channel groove 2 is helical flow channel groove;Several flow channel holes 3 are communicated between adjacent flow channel grooves 2, preferably, the number of flow channel hole 3 corresponding to each flow channel groove 2 is 10~60, the diameter of flow channel hole 3 is 1~12mm;The first air inlet hole 4 and the second air inlet hole 5 are opened in several in the mixer body 1 inside along radial direction, the cross-sectional shape of the first air inlet hole 4 and the second air inlet hole 5 is different.The first air inlet hole 4 is oval air inlet hole, the second air inlet hole 5 is circular air inlet hole;The first air inlet hole 4 and the second air inlet hole 5 are scattered distribution from the radial section center of mixer body 1 to radial section edge, form inner and outer layered structure;The first air inlet hole 4 includes center air inlet hole 41 and outer layer air inlet hole 42, the center air inlet hole 41 is located at the radial section center of mixer body 1, the outer layer air inlet hole 42 is close to the radial section edge of mixer body 1, and it is circumferentially distributed along the outside of center air inlet hole 41;The second air inlet hole 5 is evenly distributed between center air inlet hole 41 and outer layer air inlet hole 42.The first air inlet 4 is set to 7, wherein the center air inlet hole 41 is 1, and the outer layer air inlet hole 42 is set to 6;The second air inlet 5 is set to 8 and evenly surrounds the center air inlet hole 41.The length diameter of the first air inlet hole 4 and the diameter of the second air inlet hole 5 are all less than the groove depth of the flow channel groove 2.

[0053] In CFD simulation analysis can be analyzed under real working conditions Fluid flow state and flow characteristics, to a certain extent, accurately reflect the relevant performance of the static mixer. Simulation software ANSYS Workbench is used for simulation calculation, and FLUENT module is used for flow field calculation. RNG k-ε turbulence model is selected, wall function selects enhanced wall function, opens energy equation and component transport model, and gravity acceleration is set to-9.81m / s 2Boundary conditions: both inlets are set as velocity inlets, where CH4 inlet velocity is set as 3 m / s, H2 inlet velocity is set as 7 m / s, pressure outlet is set as outlet boundary outlet boundary condition, pressure value is set as 0 Pa, fluid-structure coupling interface and symmetric face boundary are set as wall; convergence parameters are set, SIMPLE algorithm is used; convergence factor and convergence accuracy are set, 6000 steps of iteration are set, calculation is carried out after initialization. In order to explore the flow characteristics of the fluid in the static mixer for natural gas-hydrogen mixing system, the non-flow parts of the model and part of the features that do not affect the overall performance are simplified in the three-dimensional mechanical design software SolidWorks. The model is imported into the Geometry module of the finite element analysis software ANSYS to extract the flow channel, and the internal flow channel geometric model of the structure is obtained. After extracting the fluid domain, hexahedral mesh is used for meshing, and the number of meshes is 1.36 million. Under the condition that the CH4 inlet gas velocity is 3 m / s and the H2 inlet gas velocity is 7 m / s, the high-efficiency low-pressure-drop static mixer for natural gas-hydrogen mixing system is simulated to obtain the pressure distribution cloud map, mixing uniformity change graph and velocity vector distribution cloud map, as shown in Figure 2 、 Figure 3 and Figure 4 respectively. It can be seen from Figure 2 that the pressure in the pipeline gradually decreases from left to right, and the high-pressure area is concentrated at the left inlet, and gradually decreases after passing through the T-shaped joint area. Due to the addition of the mixer at the T-shaped joint, the pressure appears local increase and decrease, which is caused by the change of gas flow velocity and turbulent effect after entering the mixer. Although the gas flow is disturbed and mixed in the mixer, the overall pressure drop remains at a low level, which meets the design concept of low pressure drop of the mixer. The pressure distribution after the mixer gradually stabilizes, indicating that the gas flow has reached a uniform state after passing through the mixer, verifying its low pressure drop and high efficiency mixing characteristics in the T-shaped hydrogen-doped natural gas pipeline. From Figure 3 it can be seen that the mixing uniformity of hydrogen-doped natural gas changes at different cross sections of the T-shaped hydrogen-doped natural gas pipeline after flowing through the mixer structure. At a distance of 200 mm from the outlet of the mixer, the mixing uniformity is 99.89%, at a distance of 400 mm from the outlet of the mixer, the mixing uniformity is 99.95%, and at a distance of 600 mm from the outlet of the mixer, the mixing uniformity is 99.97%. The mixing uniformity gradually increases with the increase of mixing distance, and from the data in the figure, it can be seen that the mixing uniformity has reached a very high level, and the static mixer has high efficiency. From Figure 4The flow rate distribution of the fluid and the flow of the particles in the fluid can be seen. The gas flow rate gradually decreases from left to right, and the gas flow rate is obviously increased in the vertical branch of the T-joint, forming a high-speed jet, which gradually diffuses after entering the main flow. When passing through the mixer area, the gas flow rate distribution is uneven, showing the effect of the mixer spoiler. The internal structure promotes the disturbance and shear of the gas flow rate, thereby enhancing the mixing effect of hydrogen and natural gas. At the outlet of the mixer, the gas flow rate gradually recovers and tends to be uniform, indicating that the gas has reached a relatively uniform mixing state after passing through the mixer, which meets the expected effect of the design.

[0054] Example 2

[0055] Referring to Figure 5 Different from example 1, the number of the first gas inlet holes 4 is 6, wherein the number of the central gas inlet hole 41 is 1, the number of the outer gas inlet holes 42 is 6, and the long axis direction of the outer gas inlet holes 42 is perpendicular to the radial direction of the mixer body 1; the number of the second gas inlet holes 5 is 5.

[0056] Example 3

[0057] Referring to Figure 6 Different from example 2, the long axis direction of the outer gas inlet holes 42 is arranged along the radial direction of the mixer body 1.

[0058] Example 4

[0059] Referring to Figure 7 Different from example 1, the number of the first gas inlet holes 4 is 9, wherein the number of the central gas inlet hole 41 is 1, the number of the outer gas inlet holes 42 is 8, and the long axis of the outer gas inlet holes 42 is arranged along the radial direction of the mixer body 1; the number of the second gas inlet holes 5 is 7.

[0060] Example 5

[0061] Referring to Figure 8 Different from example 1, the number of the first gas inlet holes 4 is 7, wherein the number of the central gas inlet hole 41 is 1, the number of the outer gas inlet holes 42 is 6, and the long axis of the outer gas inlet holes 42 is arranged perpendicular to the radial direction of the mixer body 1; the number of the second gas inlet holes 5 is 18.

[0062] Example 6

[0063] Referring to Figure 9Different from the embodiment 1, the first air inlet hole 4 is 9 in number, wherein the central air inlet hole 41 is 1, the outer layer air inlet hole 42 is 8, and the long axis of the outer layer air inlet hole 42 is arranged perpendicularly to the radial direction of the mixer body 1; the second air inlet hole 5 is 26.

[0064] Embodiment 7

[0065] Referring to Figure 10 Different from the embodiment 1, the first air inlet hole 4 only includes one central air inlet hole 41; the second air inlet hole 5 is 6 and is arranged circumferentially along the central air inlet hole 41.

[0066] Embodiment 8

[0067] Referring to Figure 11 Different from the embodiment 1, the first air inlet hole 4 only includes the outer layer air inlet hole 42; the second air inlet hole 5 is scattered inside the structure surrounded by the outer layer air inlet hole 42.

[0068] In the above embodiments, the arrangement of the air inlet holes is gradually increased from the center to the outer ring in layers, forming an inner-outer layered structure, that is, a small number of air inlet holes are arranged at the center position, and more holes are gradually expanded outward to achieve different degrees of fluid disturbance and mixing effect. From the variation trend of the diagram, the number and density of the air inlet holes are gradually increased, and the design from simple to complex helps to optimize the mixing efficiency and flow characteristics of the gas.

[0069] Referring to Figure 12 The utility model also provides a kind of for natural gas-hydrogen blending blending system, including natural gas inlet pipeline 6, hydrogen inlet pipeline 7, gas collection pipeline 8 and above-mentioned static mixer;The natural gas inlet pipeline 6 and hydrogen inlet pipeline 7 are all connected with gas collection pipeline 8;The static mixer is arranged in the inside of gas collection pipeline 8. Preferably, the static mixer is installed at 1 / 3 between natural gas inlet pipeline 6 and hydrogen inlet pipeline 7 convergence point to gas collection pipeline 8 outlet.The natural gas inlet pipeline 6 and hydrogen inlet pipeline 7 are vertically arranged. The length of natural gas inlet pipeline 6 is 2000mm and above, and the height of hydrogen inlet pipeline 7 is 200-1500mm.

[0070] In summary, the utility model provides a kind of static mixer and mixing system for natural gas-hydrogen blending, by the unique structure design of the integral of external flow channel groove 2 and internal first gas inlet hole 4 and second gas inlet hole 5, make mixer while realizing efficient mixing keep low pressure drop, reduce energy consumption and improve the overall efficiency of system, and the static mixer structure has no moving parts, maintenance cost is low, suitable for long time high pressure under stable operation.Can be through the adoption of corrosion-resistant materials and low friction surface treatment, show excellent reliability and adaptability in natural gas hydrogen application, and can be conveniently integrated into existing natural gas-hydrogen blending system.The pressure drop of the high-efficiency low-pressure drop static mixer for natural gas-hydrogen blending system is only 50-90Pa, which is more than 30% lower than the pressure drop of the same type of static mixer, greatly improving the mixing efficiency.

[0071] The above is only the preferred embodiment of the utility model, and does not limit the technical solutions of the utility model in any way. Those skilled in the art should understand that the technical solutions can be modified and replaced in several simple ways without departing from the spirit and principles of the utility model. These modifications and replacements are also within the scope of protection covered by the claims.

Claims

1. A static mixer for natural gas-hydrogen blending, characterized by, The static mixer comprises a mixer body (1), the outer wall of the mixer body (1) is provided with a plurality of flow channel grooves (2) in the radial direction; adjacent flow channel grooves (2) are communicated through a plurality of flow channel holes (3); a plurality of first air inlet holes (4) and second air inlet holes (5) are provided in the mixer body (1) in the radial direction, and the cross-sectional shapes of the first air inlet holes (4) and the second air inlet holes (5) are different.

2. The static mixer for natural gas-hydrogen blending of claim 1, wherein, The flow channel groove (2) is a spiral flow channel groove.

3. The static mixer for natural gas-hydrogen blending of claim 1, wherein, The first air inlet hole (4) is an elliptical air inlet hole, and the second air inlet hole (5) is a circular air inlet hole.

4. The static mixer for natural gas-hydrogen blending of claim 1, wherein, The first air inlet hole (4) and the second air inlet hole (5) are scattered and distributed from the radial section center to the radial section edge of the mixer body (1), forming an inner-outer layered structure.

5. The static mixer for natural gas-hydrogen blending of claim 1, wherein, The first air inlet hole (4) comprises a center air inlet hole (41) and an outer layer air inlet hole (42), the center air inlet hole (41) is located at the radial section center of the mixer body (1), the outer layer air inlet hole (42) is close to the radial section edge of the mixer body (1), and is distributed in a circumferential direction outside the center air inlet hole (41); the second air inlet hole (5) is uniformly distributed between the center air inlet hole (41) and the outer layer air inlet hole (42).

6. The static mixer for natural gas-hydrogen blending of claim 5, wherein, The number of the first air inlet holes (4) is 3-15, and the number of the second air inlet holes (5) is 4-32.

7. The static mixer for natural gas-hydrogen blending of any one of claims 1-6, wherein, The length of the mixer body (1) is 200-2000 mm.

8. A blending system for natural gas-hydrogen blending, characterized by, The static mixer comprises a natural gas air inlet pipeline (6), a hydrogen gas air inlet pipeline (7), a gas collection pipeline (8) and the static mixer of any one of claims 1-7; the natural gas air inlet pipeline (6) and the hydrogen gas air inlet pipeline (7) are connected with the gas collection pipeline (8); and the static mixer is arranged in the interior of the gas collection pipeline (8).

9. The mixing system for natural gas-hydrogen mixing of claim 8, wherein, The static mixer is installed at 1 / 3 of the distance between the natural gas air inlet pipeline (6) and the hydrogen gas air inlet pipeline (7) and the outlet of the gas collection pipeline (8).

10. The mixing system for natural gas-hydrogen mixing of claim 8, wherein, The natural gas air inlet pipeline (6) and the hydrogen gas air inlet pipeline (7) are arranged vertically.

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