Biomimetic DNA double-helix structure methane and hydrogen mixer and mixing method

Abstract

A methane and hydrogen mixer with a bionic DNA (deoxyribonucleic acid) double-helix structure relates to the technical field of hydrogen energy utilization, and through the DNA double-helix structure formed by two spiral columns and a guide plate, methane and hydrogen can be more fully contacted and mixed in the mixer, so that the mixing uniformity is improved. Meanwhile, the bionic DNA double-helix structure can optimize a fluid channel and flow velocity distribution in the mixing element, so that the fluid resistance is reduced, the energy loss in the mixing process is reduced, and the energy efficiency of the whole system is improved.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen energy utilization, and in particular to a bionic DNA double helix structure methane hydrogen mixer and a mixing method. Background Art

[0002] Against the backdrop of the global energy strategic transformation, the hydrogen energy industry has experienced explosive growth, but the construction cost of more than 5 million yuan per kilometer for pure hydrogen transportation pipelines has severely restricted large-scale development. The industry has proposed natural gas hydrogen blending technology, which can save more than 90% of infrastructure investment by injecting hydrogen into the existing gas pipeline network at a certain volume ratio. This model not only achieves efficient and economical transportation of hydrogen energy, but also gives full play to the inherent advantages of the natural gas pipeline network, which has wide coverage and strong adaptability. This "progressive" hydrogen energy carrier solution is becoming an important transition path for the decarbonization of the energy system.

[0003] Gas stratification seriously restricts mixing efficiency. Methane and hydrogen are difficult to mix evenly in traditional static mixers due to their significant differences in physical properties such as density and viscosity. Figure 1 As shown in the figure, existing mixers mostly rely on spiral blades or baffle structures, but due to the high diffusivity and low inertia of hydrogen, local over-concentration or stratification is prone to occur during the mixing process. Especially in low flow rate or large pipe diameter scenarios, gaseous hydrogen tends to gather at the top of the pipe, resulting in insufficient mixing uniformity. This unevenness not only reduces the calorific value stability of hydrogen-blended fuel gas, but also causes problems such as burner flashback and local high-temperature corrosion, which seriously restricts the increase in hydrogen blending ratio.

[0004] During the operation of the mixing system, the balance between energy loss and fluid resistance faces significant challenges. Although the enhanced turbulence structure designed to improve the gas mixing effect effectively shortens the mixing time of different components, the dense flow guide units will cause a sudden decrease in the cross-sectional area of ​​the flow channel, causing significant local flow resistance. This drastic change in pressure drop forces the gas delivery equipment to continuously increase power output to maintain system pressure stability, resulting in a significant reduction in energy conversion efficiency. Especially in long-distance transportation scenarios, the continuous accumulation of fluid kinetic energy loss will form a superposition effect, making the overall energy consumption level far exceed that of conventional gas delivery systems. In addition, the unique low viscosity and high diffusion characteristics of hydrogen make it easier to produce turbulent separation when passing through complex flow channels, further exacerbating the energy dissipation rate. The strong correlation between this fluid dynamics characteristic and equipment power consumption has become a key bottleneck restricting the economic operation of the system.

[0005] High concentrations of hydrogen enriched in the pipe wall will cause hydrogen embrittlement, where hydrogen atoms penetrate into the metal lattice gaps, causing a significant decrease in the material's ductility and strength. Especially in high-pressure hydrogen pipelines, hydrogen is easily retained in microscopic defects or weak welding areas, inducing local stress concentration. Over time, hydrogen atoms gather at the grain boundaries to form microcracks, eventually causing brittle fractures or even equipment failure. Such hidden dangers not only threaten the safe operation of industrial equipment, but may also cause chain risks such as hydrogen leakage and explosion.

[0006] Methane hydrogen mixers still have significant room for improvement in key technical dimensions such as improving mixing uniformity, optimizing pressure drop and energy consumption, and enhancing intrinsic safety. Summary of the invention

[0007] In order to overcome the deficiencies of the above technologies, the present invention provides a bionic DNA double helix structure methane hydrogen mixer and a mixing method for improving the uniformity of methane hydrogen mixing while reducing pressure loss.

[0008] The technical solution adopted by the present invention to overcome the technical problems is: A bionic DNA double helix structure methane hydrogen mixer, comprising: A shell is sealed on all sides and has a cavity inside. An air inlet connected to the cavity is provided at one end of the shell, and an air outlet connected to the cavity is provided at the other end of the shell; An air inlet pipe is arranged on the shell, the air inlet pipe is adjacent to the air inlet, and the air inlet pipe is connected with the cavity; Two spiral columns are arranged in the cavity, the two spiral columns are intertwined, and the two spiral columns are connected by a number of guide plates arranged at intervals. The two spiral columns and each guide plate form a DNA double helix structure, and the axis of the DNA double helix structure is coaxial with the axis of the shell.

[0009] Furthermore, the shell is in a circular tubular structure.

[0010] Furthermore, the axis of the air intake pipe is perpendicular to the axis of the shell.

[0011] Preferably, the length C of the shell is 1080 mm, and the diameter B of the shell is 100 mm.

[0012] Furthermore, the outer end of the DNA double helix structure contacts the inner wall of the shell.

[0013] Furthermore, the spiral column is made by bending X70 round steel or X80 round steel.

[0014] Preferably, the length L of the DNA double helix structure is 400 mm, the distance S between the two peaks along the helical axis is 100 mm, the diameter D of the helical column is 10 mm, and the distance R between the central axes of the two helical columns is 90 mm.

[0015] Preferably, the axial distance X between the center of the air inlet pipe and the air inlet is 200 mm, and the axial distance Y between the DNA double helix structure and the air inlet is 480 mm.

[0016] Furthermore, the longitudinal cross-section of the guide plate is a shuttle-shaped structure, the width E of the shuttle-shaped structure is 3 mm, the maximum thickness F is 0.08 mm, the length R of the guide plate is 90 mm, and the two sides of the guide plate are twisted 90 degrees in the length direction to form an arc-shaped portion, the angle N of the arc-shaped portion in the longitudinal cross-section is 5°, the radius M of the arc-shaped portion is 34.4 mm, the center distance P of the two arc-shaped portions is 68.72 mm, and the spacing A between two adjacent guide plates is 10 mm.

[0017] A mixing method using a bionic DNA double helix structure methane and hydrogen mixer comprises the following steps: S1. The methane gas pressure is set to 2.0 MPa, and the methane gas is input into the cavity of the housing (1) through the air inlet (2) at a flow rate of 15 m / s, 10 m / s or 5 m / s; S2. The hydrogen pressure is set to 2.0 MPa, and the hydrogen gas is input into the cavity of the housing (1) through the intake pipe (4) at a flow rate of 26.67 m / s, 17.78 m / s or 8.89 m / s; S3. Set the ratio of methane gas to hydrogen to 4:1; S4. The hydrogen and methane gases flow through the DNA double helix structure in the shell and are mixed evenly, and the evenly mixed gases are discharged through the outlet.

[0018] The beneficial effect of the present invention is that the DNA double helix structure formed by the two spiral columns and the guide plate can make methane and hydrogen contact and mix more fully in the mixer, thereby improving the mixing uniformity. At the same time, the bionic DNA double helix structure can optimize the fluid channel and flow rate distribution inside the mixing element, thereby reducing fluid resistance, reducing energy loss during the mixing process, and improving the energy efficiency of the entire system. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of a traditional methane hydrogen mixer; Figure 2 It is a structural diagram of the present invention; Figure 3 It is the three views of the structure of the present invention; Figure 4 is a schematic diagram of the DNA double helix structure of the present invention; Figure 5 The three views of the DNA double helix structure of the present invention; Figure 6is a schematic cross-sectional view of the guide plate portion of the present invention; Figure 7 It is a three-dimensional structural diagram of the guide plate part of the present invention; Figure 8 Three views of the guide plate of the present invention; Fig. 9 This is the simulation result diagram of the outlet concentration distribution of the traditional methane hydrogen mixer when the methane inlet flow rate is 15m / s; Fig.10 This is a simulation result diagram of the outlet concentration distribution of the bionic DNA double helix structure methane-hydrogen mixer of the present invention when the methane inlet flow rate is 15 m / s; Fig.11 This is the simulation result diagram of the outlet concentration distribution of the traditional methane hydrogen mixer when the methane inlet flow rate is 10m / s; Fig.12 This is a simulation result diagram of the outlet concentration distribution of the bionic DNA double helix structure methane-hydrogen mixer of the present invention when the methane inlet flow rate is 10 m / s; Fig.13 This is the simulation result diagram of the outlet concentration distribution of the traditional methane hydrogen mixer when the methane inlet flow rate is 5m / s; Fig.14 This is a simulation result diagram of the outlet concentration distribution of the bionic DNA double helix structure methane-hydrogen mixer of the present invention when the methane inlet flow rate is 5 m / s; In the figure, 1. shell 2. air inlet 3. air outlet 4. air inlet pipe 5. spiral column 6. guide plate. DETAILED DESCRIPTION

[0020] The following is combined with Figure 2 To Attachment Figure 8 The present invention is further described.

[0021] A bionic DNA double helix structure methane hydrogen mixer comprises: a shell 1 which is sealed on all sides and has a cavity inside, an air inlet 2 connected to the cavity is arranged at one end of the shell 1, and an air outlet 3 connected to the cavity is arranged at the other end; an air inlet pipe 4 is arranged on the shell 1, the air inlet pipe 4 is adjacent to the air inlet 2, and the air inlet pipe 4 is connected to the cavity; two spiral columns 5 are arranged in the cavity, the two spiral columns 5 are intertwined, and the two spiral columns 5 are connected by a plurality of guide plates 6 arranged at intervals, the two spiral columns 5 and each guide plate 6 form a DNA double helix structure, and the axis of the DNA double helix structure is coaxial with the axis of the shell 1.

[0022] The synergistic effect of the spiral column 5 and the guide plate 6 realizes the topological optimization of the fluid resistance. The guide plate 6 is arranged in a gradient along the spiral trajectory, decomposing the overall flow field into a multi-layer micro-scale vortex group, so that the pressure drop energy is dissipated through the discretized vortex ring, rather than the concentrated cross-sectional impact of the traditional structure. A graded dissipative topological structure is adopted, and a multi-scale vortex generating unit is constructed to make the fluid kinetic energy present a gradient vortex energy conversion along the axial direction, rather than generating a centralized impedance dissipation. The guide plate 6 adopts an aerodynamic surface, which is arranged in a circumferential spiral to form a progressive flow channel. The outer wing accelerates the fluid peeling through a specific angle of attack, and the inner wing constructs a low-pressure adsorption zone. The two cooperate to trigger a bidirectional shear effect, prompting the generation of continuous and staggered turbulent vortex rings between fluid layers. The tapered structure of the trailing edge of the wing effectively suppresses flow separation, and deeply interweaves the fluids of different phases through the secondary flow reorganization mechanism, so that the mixed contact area increases by orders of magnitude. This design significantly shortens the mixing cycle while maintaining low energy consumption, and especially demonstrates excellent homogenization capabilities for high-viscosity fluids. Its mixing efficiency is significantly improved compared to traditional structures.

[0023] The DNA double helix structure solves the problem of hydrogen directly hitting the tube wall in traditional spiral mixing elements. The guide plate 6 is arranged in the shell 1, which can disperse the hydrogen into multiple small airflows and make them flow in the center area of ​​the flow channel. The contact area between high-concentration hydrogen and the tube wall is greatly reduced. At the same time, a continuous airflow buffer layer is formed through the double helix path, which significantly delays the hydrogen embrittlement of the metal tube wall, thereby extending the service life of the equipment.

[0024] In one embodiment of the present invention, the shell 1 is in a circular tubular structure. The axis of the air intake pipe 4 is perpendicular to the axis of the shell 1. The shell 1 and the air intake pipe 4 are in a T-shaped structure, methane is input from one end of the shell 1, hydrogen is injected through the vertical air intake pipe 4, and the mixed gas is output from the other end of the shell 1. With this structure, the overall layout is compact, the standardized design has a high penetration rate, and only local modifications are required to adapt to different flow or medium requirements. The shell 1 material has strong versatility and does not require overall pipeline reconstruction, which greatly reduces the modification cost. In this embodiment, the length C of the shell 1 is 1080 mm, and the diameter B of the shell 1 is 100 mm.

[0025] In one embodiment of the present invention, the outer end of the DNA double helix structure is in contact with the inner wall of the shell 1. The spiral column 5 is made of X70 round steel or X80 round steel by bending. The spiral column 5 forms the main frame of the DNA double helix structure by rotating and twisting 720° along the axis. In this embodiment, preferably, the length L of the DNA double helix structure is 400mm, the distance S between the two peaks along the spiral axis direction is 100mm, the diameter D of the spiral column 5 is 10mm, and the center axis distance R of the two spiral columns 5 is 90mm. The axial distance X between the center of the air inlet pipe 4 and the air inlet 2 is 200mm, and the axial distance Y between the DNA double helix structure and the air inlet 2 is 480mm.

[0026] In one embodiment of the present invention, the guide plate 6 has a fusiform structure in the longitudinal section, the width E of the fusiform structure is 3 mm, the maximum thickness F is 0.08 mm, the length R of the guide plate 6 is 90 mm, and the two sides of the guide plate 6 are respectively twisted 90 degrees in the length direction to form an arc-shaped portion, the angle N of the arc-shaped portion in the longitudinal section is 5°, the radius M of the arc-shaped portion is 34.4 mm, the center distance P of the two arc-shaped portions is 68.72 mm, and the spacing A between two adjacent guide plates 6 is 10 mm. The guide plate 6 adopts a leading edge blunting and a trailing edge tapering design. While maintaining the structural strength, its asymmetric curved surface can guide the fluid to form a laminar boundary layer along the airfoil surface, significantly reducing the vortex resistance generated by flow separation.

[0027] A mixing method using a bionic DNA double helix structure methane and hydrogen mixer comprises the following steps: S1. The methane gas pressure is set to 2.0 MPa, and the methane gas is input into the cavity of the shell (1) through the gas inlet (2) at a flow rate of 15 m / s, 10 m / s or 5 m / s.

[0028] S2. The hydrogen pressure is set to 2.0 MPa, and the hydrogen gas is introduced into the cavity of the housing (1) through the air inlet pipe (4) at a flow rate of 26.67 m / s, 17.78 m / s, or 8.89 m / s.

[0029] S3. Set the ratio of methane gas to hydrogen gas to 4:1.

[0030] S4. The hydrogen and methane gases flow through the DNA double helix structure in the shell 1 and are evenly mixed, and the evenly mixed gases are discharged through the gas outlet 3.

[0031] The multi-physics modeling software COMSOL was used to simulate the two models and calculate the mixing uniformity at the outlet of the methane-hydrogen mixer.

[0032] A major indicator for measuring the mixing performance of a methane-hydrogen mixer is the mixing uniformity of the gas. There are many methods for evaluating the mixing effect. The present invention uses the widely used coefficient of variation (COV) to measure the mixing uniformity. The COV is equal to the ratio of the standard deviation of the sample volume fraction to the average sample volume fraction. The smaller the COV value, the more uniform the gas mixing.

[0033] As attached Fig. 9 , Attachment Fig.11 and attached Fig.13As shown in the figure, the simulation results of the outlet concentration distribution of the conventional methane hydrogen mixer when the methane inlet flow rate is 15m / s, 10m / s and 5m / s respectively. It can be seen from the figure that if a conventional mixing element is used, the methane hydrogen concentration difference at the outlet section of the mixer is 29mol / m3, 24mol / m3 and 20mol / m3 respectively, and the corresponding coefficients of variation are 6.11%, 5.93% and 5.85% respectively, which is difficult to meet the industrial mixing requirements. At the same time, there is an obvious near-wall hydrogen concentration enrichment phenomenon in the flow field, and this distribution characteristic may accelerate the hydrogen embrittlement process of the material.

[0034] As attached Fig.10 , Attachment Fig.12 and attached Fig.14 As shown in the figure, the simulation results of the outlet concentration distribution of the bionic DNA double helix structure methane hydrogen mixer of the present invention when the methane inlet flow rate is 15m / s, 10m / s and 5m / s respectively. It can be seen from the figure that if the mixing element is optimized and the bionic DNA double helix structure is adopted, the methane hydrogen concentration difference of the mixer outlet cross section is 16mol / m3, 13mol / m3 and 12mol / m3 respectively, and the corresponding coefficients of variation are 2.13%, 1.84% and 1.19% respectively, which can meet industrial requirements, and there will be no abnormal accumulation of hydrogen on the pipe wall, thereby delaying the occurrence of hydrogen embrittlement.

[0035] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A bionic DNA double helix structure methane hydrogen mixer, characterized in that: include: A shell (1) is sealed on all sides and has a cavity inside. An air inlet (2) connected to the cavity is provided at one end of the shell (1), and an air outlet (3) connected to the cavity is provided at the other end of the shell (1); An air intake pipe (4) is arranged on the housing (1), the air intake pipe (4) is adjacent to the air intake port (2), and the air intake pipe (4) is in communication with the cavity; Two spiral columns (5) are arranged in the cavity. The two spiral columns (5) are intertwined with each other. The two spiral columns (5) are connected via a plurality of flow guide plates (6) arranged at intervals. The two spiral columns (5) and the flow guide plates (6) form a DNA double helix structure. The axis of the DNA double helix structure is coaxial with the axis of the shell (1).

2. The bionic DNA double helix structure methane hydrogen mixer according to claim 1, characterized in that: The shell (1) is in a circular tubular structure.

3. The bionic DNA double helix structure methane hydrogen mixer according to claim 2, characterized in that: The axis of the air intake pipe (4) is perpendicular to the axis of the housing (1).

4. The bionic DNA double helix structure methane and hydrogen mixer according to claim 2, characterized in that: The length C of the shell (1) is 1080 mm, and the diameter B of the shell (1) is 100 mm.

5. The bionic DNA double helix structure methane hydrogen mixer according to claim 1, characterized in that: The outer end of the DNA double helix structure contacts the inner wall of the shell (1).

6. The bionic DNA double helix structure methane and hydrogen mixer according to claim 1, characterized in that: The spiral column (5) is made by bending X70 round steel or X80 round steel.

7. The bionic DNA double helix structure methane and hydrogen mixer according to claim 6, characterized in that: The length L of the DNA double helix structure is 400 mm, the distance S between the two peaks along the helical axis is 100 mm, the diameter D of the helical column (5) is 10 mm, and the distance R between the central axes of the two helical columns (5) is 90 mm.

8. The bionic DNA double helix structure methane and hydrogen mixer according to claim 3, characterized in that: The axial distance X between the center of the air inlet pipe (4) and the air inlet (2) is 200 mm, and the axial distance Y between the DNA double helix structure and the air inlet (2) is 480 mm.

9. The bionic DNA double helix structure methane and hydrogen mixer according to claim 1, characterized in that: The guide plate (6) has a shuttle-shaped structure in the longitudinal section, the width E of the shuttle-shaped structure is 3 mm, the maximum thickness F is 0.08 mm, the length R of the guide plate (6) is 90 mm, the two sides of the guide plate (6) are respectively twisted 90 degrees in the length direction to form an arc-shaped portion, the angle N of the arc-shaped portion in the longitudinal section is 5°, the radius M of the arc-shaped portion is 34.4 mm, the distance P between the centers of the two arc-shaped portions is 68.72 mm, and the spacing A between two adjacent guide plates (6) is 10 mm.

10. A mixing method using the bionic DNA double helix structure methane hydrogen mixer according to any one of claims 1 to 9, characterized in that: The steps include: S1. The methane gas pressure is set to 2.0 MPa, and the methane gas is input into the cavity of the housing (1) through the air inlet (2) at a flow rate of 15 m / s, 10 m / s or 5 m / s; S2. The hydrogen pressure is set to 2.0 MPa, and the hydrogen gas is input into the cavity of the housing (1) through the intake pipe (4) at a flow rate of 26.67 m / s, 17.78 m / s or 8.89 m / s; S3. Set the ratio of methane gas to hydrogen to 4:1; S4. The hydrogen gas and the methane gas flow through the DNA double helix structure in the shell (1) and are evenly mixed, and the evenly mixed gas is discharged through the gas outlet (3).

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