A biomimetic DNA double helix structure methane hydrogen mixer and mixing method

Abstract

The application discloses a biomimetic DNA double helix structure methane hydrogen mixer, relates to the technical field of hydrogen energy utilization, and can make methane and hydrogen more fully contact and mix in the mixer through a DNA double helix structure formed by two spiral columns and a guide plate, so that the mixing uniformity is improved. Meanwhile, the biomimetic DNA double helix structure can optimize the 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] This invention relates to the field of hydrogen energy utilization technology, specifically to a biomimetic DNA double helix structure methane-hydrogen mixer and mixing method. Background Technology

[0002] The construction cost of over 5 million yuan per kilometer for pure hydrogen transportation pipelines severely restricts large-scale development. The industry has proposed a natural gas-hydrogen blending technology, which, by injecting hydrogen into existing gas pipelines at a certain volume ratio, can save over 90% of infrastructure investment. This model not only achieves efficient and economical hydrogen transportation but also leverages the inherent advantages of natural gas pipelines, such as wide coverage and strong adaptability. This "gradual" hydrogen energy carrier solution is becoming an important transitional path for the decarbonization of the energy system.

[0003] Gas stratification severely restricts mixing efficiency. Due to significant differences in density, viscosity, and other physical properties, methane and hydrogen are difficult to mix uniformly in traditional static mixers. (See attached image) Figure 1 As shown, existing mixers mostly rely on helical blades or baffle structures, but due to the high diffusivity and low inertia of hydrogen, localized excessive concentrations or stratification are prone to occur during the mixing process. Especially in low flow rate or large pipe diameter scenarios, gaseous hydrogen tends to accumulate at the top of the pipe, resulting in insufficient mixing uniformity. This non-uniformity not only reduces the calorific value stability of the hydrogen-blended fuel gas, but also causes problems such as burner backfire and localized high-temperature corrosion, severely restricting the improvement of the hydrogen blending ratio.

[0004] During the operation of a mixing system, the balance between energy loss and fluid resistance faces significant challenges. While enhanced turbulence structures designed to improve gas mixing effectively shorten the mixing time of different components, the dense flow-guiding units cause a sharp reduction in the cross-sectional area of ​​the flow channel, leading to significant local flow resistance. This drastic pressure drop forces the gas delivery equipment to continuously increase its power output to maintain system pressure stability, resulting in a substantial decrease in energy conversion efficiency. Especially in long-distance transportation scenarios, the continuous accumulation of fluid kinetic energy loss creates a cumulative effect, making the overall energy consumption level far exceed that of conventional gas delivery systems. Furthermore, the unique low viscosity and high diffusion characteristics of hydrogen make it more prone to turbulent separation when passing through complex flow channels, further exacerbating the energy dissipation rate. This strong correlation between fluid dynamics and equipment power consumption becomes a key bottleneck restricting the economical operation of the system.

[0005] High concentrations of hydrogen accumulating on pipe walls can cause hydrogen embrittlement, where hydrogen atoms penetrate the interstitial spaces of the metal lattice, leading to a significant decrease in the material's ductility and strength. This is especially problematic in high-pressure hydrogen pipelines, where hydrogen can easily accumulate in microscopic defects or weak welded areas, inducing localized stress concentrations. Over time, hydrogen atoms accumulate at grain boundaries, forming microcracks that eventually lead to brittle fracture and even equipment failure. Such hazards not only threaten the safe operation of industrial equipment but can also cause a chain reaction of risks, including hydrogen leaks and explosions.

[0006] The methane-hydrogen mixer still has a significant improvement space in key technical dimensions such as improvement of mixing uniformity, optimization of pressure drop energy consumption, and enhancement of intrinsic safety. SUMMARY

[0007] The present application provides a biomimetic DNA double helix structure methane-hydrogen mixer and a mixing method for improving methane-hydrogen mixing uniformity while reducing pressure loss.

[0008] The technical solution adopted by the present application to overcome the technical problems is:

[0009] A biomimetic DNA double helix structure methane-hydrogen mixer comprises:

[0010] A shell is closed around its periphery, and a cavity is arranged inside the shell.

[0011] An air inlet is arranged at one end of the shell and communicates with the cavity.

[0012] Two spiral columns are arranged in the cavity, and the two spiral columns are wound around each other.

[0013] Further, the shell has a circular tube structure.

[0014] Further, the axis of the air inlet pipe is perpendicular to the axis of the shell.

[0015] Preferably, the length C of the shell is 1080 mm, and the diameter B of the shell is 100 mm.

[0016] Further, the outer end of the DNA double helix structure is in contact with the inner wall of the shell.

[0017] Further, the spiral column is made of X70 round steel or X80 round steel.

[0018] Preferably, the length L of the DNA double helix structure is 400 mm, the distance S between the two peaks in the spiral axis direction is 100 mm, the diameter D of the spiral column is 10 mm, and the center axis distance R between the two spiral columns is 90 mm.

[0019] 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.

[0020] Further, the above-mentioned guide plate longitudinal section is in a shuttle-shaped structure, the width E of the shuttle-shaped structure is 3mm, the maximum thickness F is 0.08mm, the length R of the guide plate is 90mm, the guide plate is twisted by 90 degrees in the length direction on both sides to form an arc-shaped part, the angle N of the arc-shaped part on the longitudinal section is 5°, the radius M of the arc-shaped part is 34.4mm, the center distance P of the two arc-shaped parts is 68.72mm, and the spacing A between two adjacent guide plates is 10mm.

[0021] A mixing method using a biomimetic DNA double helix structure methane hydrogen gas mixer, comprising the following steps:

[0022] S1. Set the methane gas pressure to 2.0MPa, and input the methane gas into the cavity of the shell (1) through the gas inlet (2) at a flow rate of 15m / s or 10m / s or 5m / s;

[0023] S2. Set the hydrogen pressure to 2.0MPa, and input the hydrogen gas into the cavity of the shell (1) through the gas inlet pipe (4) at a flow rate of 26.67m / s or 17.78m / s or 8.89m / s;

[0024] S3. Set the ratio of methane gas to hydrogen to be 4:1;

[0025] S4. The hydrogen and methane gas flow through the DNA double helix structure in the shell and are uniformly mixed, and the uniformly mixed gas is discharged through the gas outlet.

[0026] The beneficial effects of the present application are: the DNA double helix structure formed by the two spiral columns and the guide plate can make methane and hydrogen more fully contact and mix in the mixer, thereby improving the uniformity of mixing. At the same time, the biomimetic DNA double helix structure can optimize the fluid channel and flow rate distribution inside the mixing element, thereby reducing fluid resistance, reducing energy loss in the mixing process, and improving the energy efficiency of the entire system. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a traditional methane hydrogen gas mixer;

[0028] Figure 2 It is a structural diagram of the present application;

[0029] Figure 3 It is a three-view structure of the present application;

[0030] Figure 4 It is a schematic diagram of the DNA double helix structure of the present application;

[0031] Figure 5 It is a three-view diagram of the DNA double helix structure of the present application;

[0032] Figure 6 A cross-sectional view of the flow guide part of the present application;

[0033] Figure 7 A perspective view of the flow guide part of the present application;

[0034] Figure 8 A three-view of the flow guide part of the present application;

[0035] Figure 9 A simulation result diagram of the outlet concentration distribution of a traditional methane-hydrogen mixer when the methane inlet flow rate is 15 m / s;

[0036] Figure 10 A simulation result diagram of the outlet concentration distribution of the biomimetic DNA double helix structure methane-hydrogen mixer of the present application when the methane inlet flow rate is 15 m / s;

[0037] Figure 11 A simulation result diagram of the outlet concentration distribution of a traditional methane-hydrogen mixer when the methane inlet flow rate is 10 m / s;

[0038] Figure 12 A simulation result diagram of the outlet concentration distribution of the biomimetic DNA double helix structure methane-hydrogen mixer of the present application when the methane inlet flow rate is 10 m / s;

[0039] Figure 13 A simulation result diagram of the outlet concentration distribution of a traditional methane-hydrogen mixer when the methane inlet flow rate is 5 m / s;

[0040] Figure 14 A simulation result diagram of the outlet concentration distribution of the biomimetic DNA double helix structure methane-hydrogen mixer of the present application when the methane inlet flow rate is 5 m / s;

[0041] In the figure, 1. shell 2. gas inlet 3. gas outlet 4. gas inlet pipe 5. spiral column 6. flow guide plate. DETAILED DESCRIPTION

[0042] The present application will be further described below with reference to the accompanying drawings. Figure 2 to the accompanying drawings Figure 8 The present application will be further described below with reference to the accompanying drawings.

[0043] The application discloses a biomimetic DNA double helix structure methane hydrogen mixer, which comprises a shell 1, the periphery of which is closed, and a cavity is arranged in the shell 1; one end of the shell 1 is provided with an air inlet 2 which is communicated with the cavity, and the other end of the shell 1 is provided with an air outlet 3 which is communicated with the cavity; 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 communicated with the cavity; two spiral columns 5 are arranged in the cavity, the two spiral columns 5 are wound with each other, and the two spiral columns 5 are connected through a plurality of interval arranged flow guide plates 6, the two spiral columns 5 and the flow guide plates 6 form a DNA double helix structure, and the axis of the DNA double helix structure is the same as the axis of the shell 1.

[0044] The spiral column 5 and the flow guide plate 6 are cooperated to realize topological optimization of fluid resistance. The flow guide plates 6 are arranged in a gradient along a spiral track, the overall flow field is decomposed into a plurality of micro scale vortex groups, the pressure drop energy is dissipated through the discrete vortex ring, and the concentrated section impact of the traditional structure is avoided. The hierarchical dissipation topological structure is adopted, the multi-scale vortex generating unit is constructed, the fluid kinetic energy is presented in a gradient vortex energy conversion along the axial direction, and the concentrated impedance dissipation is avoided. The flow guide plate 6 adopts an aerodynamic curved surface, a progressive flow channel is formed through the circumferential spiral arrangement, the outer side wing piece accelerates fluid stripping through a specific attack angle, the inner side wing piece constructs a low-pressure adsorption area, and the two are cooperated to trigger a bidirectional shear effect, so that continuous interlaced turbulent vortex rings are generated between fluid layers. The taper structure of the wing piece trailing edge effectively suppresses flow separation, and through a secondary flow recombination mechanism, different phase fluids are deeply interlaced, so that the mixing contact area is increased by an order of magnitude. The design keeps low energy consumption, significantly shortens the mixing period, and especially exhibits excellent homogenization ability for high viscosity fluids, and the mixing efficiency is greatly improved compared with the traditional structure.

[0045] The DNA double helix structure is arranged to solve the problem that hydrogen directly impacts the pipe wall in the traditional spiral mixing element. The flow guide plates 6 are arranged in the shell 1, hydrogen can be dispersed into a plurality of small gas flows, and the hydrogen is caused to flow in the central region of the flow channel. The contact area of high-concentration hydrogen and the pipe wall is greatly reduced, and a continuous gas flow buffer layer is formed through the double helix path, so that the hydrogen embrittlement phenomenon of the metal pipe wall is significantly delayed, and the service life of the equipment is prolonged.

[0046] In an embodiment of the application, the shell 1 is in a circular pipe structure. The axis of the air inlet pipe 4 is perpendicular to the axis of the shell 1. The shell 1 and the air inlet 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 inlet pipe 4, and mixed gas is output from the other end of the shell 1. Through the structure, the overall layout is compact, the standardization design popularization rate is high, only partial modification is needed to adapt to different flow or medium requirements, the shell 1 material has strong universality, and the overall pipeline reconstruction is not needed, so that the reconstruction cost is greatly reduced. In the embodiment, the length C of the shell 1 is 1080 mm, and the diameter B of the shell 1 is 100 mm.

[0047] In one embodiment of the present application, the outer side of the DNA double helix structure is in contact with the inner wall of the shell 1. The helical column 5 is bent from X70 round steel or X80 round steel. The helical column 5 forms the main frame of the DNA double helix structure by rotating and twisting 720° along the axis. In this embodiment, the length L of the DNA double helix structure is preferably 400 mm, the distance S between the two peaks in the direction of the helical axis is 100 mm, the diameter D of the helical column 5 is 10 mm, and the distance R between the center axes of the two helical columns 5 is 90 mm. The center of the inlet pipe 4 is axially spaced from the inlet 2 by a distance X of 200 mm, and the DNA double helix structure is axially spaced from the inlet 2 by a distance Y of 480 mm.

[0048] In one embodiment of the present application, the guide plate 6 has a longitudinal cross-section in the shape of a shuttle, 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 guide plate 6 is twisted by 90 degrees in the length direction on both sides to form an arc-shaped part, the angle N of the arc-shaped part in the longitudinal cross-section is 5°, the radius M of the arc-shaped part is 34.4 mm, the center distance P of the two arc-shaped parts is 68.72 mm, and the distance A between two adjacent guide plates 6 is 10 mm. The guide plate 6 is designed with a blunt leading edge and a tapered trailing edge to maintain structural strength while its asymmetric curved surface can guide the fluid to form a laminar boundary layer along the airfoil surface, significantly reducing the vortex resistance caused by flow separation.

[0049] A mixing method using a biomimetic DNA double helix structure methane hydrogen gas mixer, comprising the following steps:

[0050] S1. Set the pressure of the methane gas to 2.0 MPa, and input the methane gas into the cavity of the shell (1) through the inlet (2) at a flow rate of 15 m / s or 10 m / s or 5 m / s.

[0051] S2. Set the pressure of the hydrogen gas to 2.0 MPa, and input the hydrogen gas into the cavity of the shell (1) through the inlet pipe (4) at a flow rate of 26.67 m / s or 17.78 m / s or 8.89 m / s.

[0052] S3. Set the ratio of methane gas to hydrogen gas to be 4:1.

[0053] S4. The hydrogen and methane gas are mixed uniformly after flowing through the DNA double helix structure in the shell 1, and the uniformly mixed gas is discharged through the outlet 3.

[0054] The two models are simulated using multi-physical field modeling software COMSOL, and the mixing uniformity at the outlet of the methane hydrogen gas mixer is calculated.

[0055] A key indicator for evaluating the mixing performance of a methane-hydrogen mixer is the uniformity of gas mixing. While there are many methods for evaluating mixing effectiveness, this invention uses the widely adopted coefficient of variation (COV) to measure mixing uniformity. The COV is equal to the ratio of the standard deviation of the sample volume fraction to the sample mean volume fraction. A smaller COV value indicates more uniform gas mixing.

[0056] As attached Figure 9 Appendix Figure 11 and attached Figure 13 The figure shows the simulated outlet concentration distribution of a conventional methane-hydrogen mixer at methane inlet velocities of 15 m / s, 10 m / s, and 5 m / s. As can be seen from the figure, if conventional mixing elements are used, the methane-hydrogen concentration differences at the mixer outlet cross-section are 29 mol / m³, 24 mol / m³, and 20 mol / m³, with corresponding coefficients of variation of 6.11%, 5.93%, and 5.85%, respectively, which are insufficient to meet industrial mixing requirements. Furthermore, a significant near-wall hydrogen concentration enrichment phenomenon is observed in the flow field, and this distribution characteristic may accelerate the hydrogen embrittlement process of the material.

[0057] As attached Figure 10 Appendix Figure 12 and attached Figure 14 As shown in the figure, the simulated results of the outlet concentration distribution of the biomimetic DNA double helix structure methane-hydrogen mixer of the present invention at methane inlet flow velocities of 15 m / s, 10 m / s, and 5 m / s are as follows. It can be seen from the figure that if the mixing element is optimized and a biomimetic DNA double helix structure is adopted, the methane-hydrogen concentration difference at the mixer outlet section is 16 mol / m3, 13 mol / m3, and 12 mol / m3, respectively, with corresponding coefficients of variation of 2.13%, 1.84%, and 1.19%, which can meet industrial requirements and will not cause abnormal hydrogen accumulation on the pipe wall, thus delaying the occurrence of hydrogen embrittlement.

[0058] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A biomimetic DNA double helix structure methane-hydrogen mixer, characterized in that, include: The shell (1) is sealed on all sides and has a cavity inside. One end of the shell (1) is provided with an air inlet (2) connected to the cavity, and the other end is provided with an air outlet (3) connected to the cavity. An air inlet pipe (4) is installed on the housing (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 helical columns (5) are placed in the cavity. The two helical columns (5) are intertwined and connected to each other by several spaced guide plates (6). The two helical columns (5) and each guide plate (6) form a DNA double helix structure. The axis of the DNA double helix structure is the same as the axis of the shell (1). The guide plate (6) has a spindle-shaped structure in its longitudinal section. The width E of the spindle-shaped 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 twisted 90 degrees in their length direction to form arc-shaped parts. The angle N of the arc-shaped parts in the longitudinal section is 5°, the radius M of the arc-shaped parts is 34.4 mm, the center distance P between the two arc-shaped parts is 68.72 mm, and the distance A between the two adjacent guide plates (6) is 10 mm.

2. The biomimetic DNA double helix structure methane-hydrogen mixer according to claim 1, characterized in that: The shell (1) has a cylindrical structure.

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

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

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

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

8. The biomimetic DNA double helix structure methane-hydrogen mixer according to claim 3, characterized in that: The center of the air inlet pipe (4) and the air inlet (2) are 200 mm apart in the axial direction, and the DNA double helix structure and the air inlet (2) are 480 mm apart in the axial direction.

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