A natural gas hydrogenation mixer

Abstract

This invention relates to the field of gas refueling technology, specifically to a natural gas hydrogenation mixer. It includes an ellipsoidal shell, with an inlet pipe and an outlet pipe fixedly connected along the long axis of the shell. An inlet bellows is fixedly connected to the outlet end of the inlet pipe, located inside the shell. An outlet bellows is fixed inside the outlet pipe, with one end extending into the shell. A sealing plate is fixed to one end of the outlet bellows inside the shell. A gap is provided between the outer edge and the inner edge of the outlet bellows. Multiple air holes are formed on the expansion joints of the outlet bellows. The center of the outlet end of the inlet bellows and the center of the sealing plate coincide with two focal points along the long axis of the shell, respectively. The inlet pipe is connected to a gas swirl assembly. This technical solution induces self-excited low-frequency oscillations through a unique structural design, generating periodic pressure fluctuations alternating between high-pressure and low-pressure zones, thereby forming intense eddies and turbulence within the shell cavity.

Description

Technical Field

[0001] This invention relates to the field of gas refueling technology, specifically to a natural gas hydrogenation mixer. Background Technology

[0002] Adding hydrogen to natural gas creates a new type of fuel—hydrogen-natural gas. This fuel combines the advantages of both natural gas and hydrogen, offering faster combustion, lower carbon emissions, and greater environmental friendliness. It represents a new approach to addressing the oil crisis. Hydrogen blending technology not only improves the utilization rate of renewable energy but also contributes to reducing pollutants from the final combustion of natural gas, thus helping to solve air pollution problems and achieve carbon emission reduction.

[0003] Hydrogen-blended natural gas is a type of "shallow hydrogen fuel" where 10-20% hydrogen by volume is added to natural gas. Hydrogen has a low compressibility and is difficult to liquefy, making it challenging to transport from hydrogen plants to refueling stations. This results in high vehicle transportation costs and poor economic viability for widespread adoption. However, transporting hydrogen alongside natural gas via long-distance pipelines significantly reduces transportation costs, making it an excellent method for promoting hydrogen-blended natural gas. As a green and low-carbon secondary energy source, the large-scale transportation of hydrogen through blending it into natural gas pipelines is a current research hotspot. However, the alteration of the physical properties of hydrogen after mixing with natural gas can lead to problems such as pipeline blockage, hydrogen embrittlement, leaks, accumulation, combustion, and explosions. Since hydrogen is more explosive than natural gas and has a certain impact on pipeline materials, high requirements are placed on the blending ratio, uniformity, and safety of hydrogen in natural gas; the blending method is crucial.

[0004] Research on methods for adding hydrogen to natural gas in my country is limited to date. While there are patents for adding hydrogen at gas stations and for mixing natural gas with air, the principles and methods are similar but not entirely the same. Using hydrogen addition to natural gas in long-distance pipelines presents challenges such as small processing capacity, multiple venting issues, difficulty in controlling the hydrogen addition ratio, and uneven mixing of natural gas and hydrogen after addition. Furthermore, control of both the natural gas and hydrogen pipelines is required. Traditional natural gas pipelines lack bypasses, making maintenance inconvenient, and lack overpressure relief and return pipelines. These are all existing problems. The development of efficient natural gas hydrogenation and mixing devices is an urgent priority and key to effectively solving these problems.

[0005] Chinese invention patent application CN109469825A, entitled "A Long-Distance Pipeline Natural Gas Hydrogenation Device and Method," includes a pipeline section, a PLC controller, and a safety protection section. The pipeline section comprises a main pipeline, a first pipeline, a second pipeline, and a mixing main pipeline. A static mixer is installed on the mixing main pipeline. The PLC controller is connected to both the main pipeline and the first pipeline, adjusting the hydrogen flow rate in the first pipeline based on pressure and flow information from both pipelines. The hydrogen is then output after passing through the static mixer on the mixing main pipeline. The safety protection section provides audible and visual alarms and protects the electrical equipment to ensure safe operation in hazardous environments with explosive gases. In this process, a highly efficient and reliable natural gas hydrogenation mixer will be invaluable.

[0006] A Chinese invention patent, CN105090738B, entitled "A Multifunctional Mixing and Refueling Station and Method for Natural Gas and Hydrogen," describes a device capable of high-precision, real-time, adjustable mixing and refueling of hydrogen and natural gas. The high-pressure multifunctional refueling station system includes a natural gas supply system, a hydrogen supply system, at least one mixing and refueling machine, and a Supervisory Control and Data Acquisition (SCADA) system. The mixing and refueling machine integrates mixing and refueling functions, performing real-time refueling while mixing. This not only allows for mixing and refueling according to the customer's refueling ratio but also avoids the possibility of gas stratification that can occur in processes involving pre-mixing and storage followed by refueling. Furthermore, the mixing and refueling process eliminates the need to first adjust hydrogen and natural gas to the same pressure before mixing. Instead, it prioritizes low-pressure hydrogen refueling followed by high-pressure natural gas refueling, using a control system to adjust the hydrogen and natural gas refueling ratio, effectively preventing energy waste. Although the patent describes the multi-functional features of its gas mixing machine, it does not describe the specific structural design of the device, nor does it describe the mixing quality and efficiency of the two media when natural gas and hydrogen are mixed.

[0007] A Chinese utility model patent, "Hydrogen Transportation Device" (CN206669338U), is currently available. It includes a hydrogen storage tank, a natural gas transportation section, a hydrogen injection section, and a mixed gas transportation section. The hydrogen storage tank supplies compressed hydrogen to the hydrogen injection section. The natural gas transportation section transports natural gas. The hydrogen injection section receives hydrogen from the hydrogen storage tank and mixes it with natural gas from the natural gas transportation section to form a mixed gas. The mixed gas transportation section transports the mixed gas. The inner diameter of the hydrogen injection section is smaller than that of the natural gas transportation section, and the inner diameter of the hydrogen injection section is smaller than that of the mixed gas transportation section. This patented device modifies existing natural gas pipelines to transport hydrogen, enabling inexpensive hydrogen transportation. Furthermore, the device employs a special pipeline design that allows the hydrogen injection pressure to be significantly lower than the pressure inside the natural gas pipeline, eliminating the need to pressurize the hydrogen to a high level. This reduces hydrogen transportation costs. However, in this patented device, hydrogen is mixed into the natural gas pipeline, and the first or second transition section of the mixing section uses a tapered tube. A tapered tube is defined as a pipe with a larger diameter at one end and a smaller diameter at the other, with a smooth transition between the two ends. While this allows for smooth changes in the flow rate and pressure of the natural gas and the mixed gas, thus facilitating a more stable mixing of natural gas and hydrogen, the mixing speed and efficiency are not high. The mixing effect varies with the pipeline pressure and the flow rate of the mixing medium. When the natural gas flow rate decreases and the pressure increases, there may be a considerable distance in the pipeline where the two gases are not mixed evenly, potentially leading to gas stratification and density unevenness during pipeline transportation. Furthermore, the patented device's structural design, with a small inner diameter hydrogen injection section and tapered tube structures in both the first and second transition sections, results in a sluggish and non-compact overall structure.

[0008] Due to the significant differences in physical properties and density between natural gas and hydrogen, conventional blending methods struggle to quickly and uniformly mix them. Inhomogeneous mixing of natural gas and hydrogen can affect the stability of combustion, making it difficult to control combustion products and potentially leading to the formation of pollutants such as nitrogen oxides and other harmful gases. Therefore, there are stringent requirements regarding the proportion, uniformity, and safety of hydrogen added to natural gas. The requirement for gas uniformity in natural gas blending with hydrogen is extremely high.

[0009] A current Chinese invention patent application, "Variable Diameter Pipeline Natural Gas Hydrogen Blending Mixer" (CN119951379A), describes a device comprising a main mixer pipe with an inwardly extending tapered section at its inlet end. The smaller diameter end of the tapered section connects to an orifice injection section. A hydrogen inlet pipe is sealed and inserted through the side wall of the main mixer pipe, and its outlet connects to the injection hole of the orifice injection section. Hydrogen enters the orifice injection section via the hydrogen inlet pipe in a cross-flow jet manner to mix with natural gas. A variable diameter static mixer is also installed within the main mixer pipe. The smaller diameter section of the variable diameter static mixer can be inserted into the orifice injection section, while the larger diameter section is positioned within the main mixer pipe near the outlet end. This invention utilizes the tapered section to increase the natural gas flow rate and the orifice injection section to accelerate the hydrogen jet, fully leveraging the kinetic energy of both natural gas and hydrogen to achieve rapid, uniform, and efficient mixing of natural gas with hydrogen. However, this patented device uses a cross-flow jet injection method to mix hydrogen with natural gas into the orifice injection pipe section. This hydrogenation method can cause a flow interruption effect on the main natural gas pipeline, resulting in a significant loss of natural gas pressure. In other words, this hydrogenation method has a common technical defect.

[0010] A current Chinese invention patent application, "Natural Gas Hydrogen Blending Mixer and Blending Ratio Adjustment Method" (CN119896989A), describes a device comprising an injector, a blending pipeline, and a rectifier. The injector includes a central cavity and at least one annular cavity, coaxially arranged with the annular cavity located on the outer periphery of the central cavity. The central cavity is used to introduce natural gas, and the annular cavity is used to introduce hydrogen. Along the flow direction of the natural gas, the flow area of ​​the central cavity gradually increases towards the outlet. The blending pipeline is connected to the injector, and the rectifier is disposed inside the blending pipeline. In this invention's natural gas hydrogen blender, hydrogen surrounds the natural gas jet. Due to the velocity difference between natural gas and hydrogen, the high-speed hydrogen injection carries the low-speed natural gas flow after entering the blending pipeline, resulting in better blending of natural gas and hydrogen within the shear layer. The gradually increasing flow area on the outlet side of the central cavity increases the injection range of the natural gas, thereby increasing the contact area between natural gas and hydrogen and improving the blending effect. The patented device includes a filter and a rectifier to regulate the flow of the mixed gas (the rectifier includes multiple grid plates). The overall device has a complicated manufacturing process, high cost, and complex and expensive operation and maintenance.

[0011] A current Chinese invention patent application, "A Natural Gas Hydrogen Blending Mixer" (CN114931869A), describes a device comprising a natural gas inlet flange, a mixer housing fixedly connected to one side of the inlet flange, a hydrogen inlet injection pipe extending through the mixer housing, a fixed guide vane assembly installed inside the mixer housing at the end of the hydrogen inlet injection pipe furthest from the natural gas inlet flange, a baffle mixing module detachably connected inside the mixer housing, and a natural gas outlet flange fixedly connected to one end of the mixer housing. This invention achieves rapid initial gas mixing, increasing the uniformity of the mixture without increasing the pressure loss of the hydrogen pipeline. Simultaneously, it alters the gas flow path to achieve secondary blending. The mixed gas after these two blending stages enters the baffle mixing module, where the gas flow path is altered to achieve secondary blending. However, this patented device uses a cross-flow jet method to inject hydrogen into the orifice injection pipe section, which can cause a flow restriction on the main natural gas pipeline, resulting in significant pressure loss. In other words, this patent also suffers from the common technical defects of hydrogen doping methods.

[0012] A current Chinese invention patent application, "Hydrogen Blending Device" (CN120381766A), relates to the field of natural gas hydrogen blending technology and is used to improve the mixing effect of natural gas and hydrogen. The hydrogen blending device includes: a natural gas inlet pipe, a hydrogen inlet pipe, a blending pipe, and a blending element. The blending element is disposed inside the blending pipe. The blending element of this patented device has a complex structure, high manufacturing cost, and high maintenance costs.

[0013] A current Chinese invention patent application, "A Natural Gas-Hydrogen Blending Operating Device (CN119461784A)," describes a device used to supply mixed gas to a glass melting furnace. This device includes a mixing pipe for mixing natural gas and hydrogen. The mixing pipe has a first inlet and an outlet at both ends along a first direction, and a second inlet in the middle, angled relative to the first direction. The first inlet is connected to a natural gas source via a first pipe; the second inlet is connected to a hydrogen source via a second pipe; a reflux plate is located at the connection between the second inlet and the mixing pipe; and the outlet is connected to a third pipe. The end of the third pipe opposite to the outlet is used to transport the mixed gas formed by the uniform mixing of natural gas and hydrogen to the combustion gun of the glass melting furnace. While this patented device can promote a more uniform mixing of natural gas and hydrogen, it cannot guarantee the uniformity of the mixed gas supplied to the glass melting furnace, thus failing to achieve optimal energy saving and carbon reduction.

[0014] A current Chinese invention patent application, "A Static Rectifier for a Large-Diameter Hydrogen-Blended Natural Gas Pipeline" (CN120120495A), describes a device comprising a natural gas pipe, a hydrogen injection pipe, and a baffle pipe. The natural gas pipe has a natural gas inlet at its left end and a mixed gas outlet at its right end. The hydrogen injection pipe is a curved pipe with a reverse "L"-shaped left-hand bend, extending into the natural gas pipe. This portion is coaxial with the natural gas pipe and has three rows of hydrogen injection holes distributed around its end circumference, allowing hydrogen to be more fully injected into the natural gas pipe for pre-mixing. The invention utilizes a mandrel, baffle blades, and baffle rods within the baffle pipe to continuously divide, split, collide, and overlap the mixed gas, enhancing the uniformity of the natural gas-hydrogen mixing. However, this patented device also suffers from the same problem as traditional mixers: the mixing uniformity is difficult to guarantee, especially when the parameters of the two pipelines change. Furthermore, the pressure drop loss is also significant.

[0015] Blending hydrogen into natural gas and transporting it through existing long-distance natural gas pipelines or urban gas pipelines, or supplying hydrogen through pipelines from nearby hydrogen sources, and finally utilizing it at end users, is one of the best ways to utilize hydrogen energy on a large scale and at low cost. It is also one of the main forms of hydrogen energy utilization. By injecting hydrogen produced by the electrolysis of renewable energy or excess hydrogen generated under full-load operation of hydrogen refueling stations into the natural gas pipeline network to form hydrogen-blended natural gas, and then transporting the hydrogen-blended natural gas to end users through the pipeline network, a hydrogen energy industry chain of "blending-transportation-utilization" is realized, promoting the deep integration of "hydrogen energy and gas network".

[0016] Natural gas blending technology has been commercially applied in several European countries, accumulating rich operational experience. Existing static mixers abroad include the Kenics type developed by Kenics in the US, the LPD type from New York, and the SMX, SMV, and SMI types developed by Sullair in Switzerland. In China, the overall technology level of natural gas blending is still in the experimental verification stage, especially regarding the core component, the natural gas blending mixer, where there are no unified standards for process advancement, mixing uniformity, pressure drop suitability, and material applicability. Domestic static mixers mainly include the SK, SH, SX, SL, and SV types. Currently, many blenders in my country suffer from problems such as large natural gas pressure loss, poor blending effect, complex device structure, high manufacturing cost, and inconvenient operation and maintenance. Different mixers have different mixing principles and effects. As actual engineering conditions become increasingly complex, especially in the application of large-diameter natural gas blending pipelines, traditional mixers cannot simultaneously address the mixing uniformity and pressure drop loss of the blended fluids in practical engineering projects.

[0017] Due to the significant differences in properties between hydrogen and methane, hydrogen is prone to stratification after entering a natural gas pipeline, leading to excessively high local hydrogen concentrations. This can cause hydrogen embrittlement during pipeline transport, and the uneven gas mixture entering downstream terminals directly impacts user safety. Therefore, ensuring the uniformity of natural gas and hydrogen blending is one of the key issues in the field of natural gas hydrogen blending technology. As the core of natural gas hydrogen blending technology, the structure of the blender significantly influences its development. Advanced blending processes place high demands on the internal structure of the mixer; only a reasonable and advanced structure and arrangement can guarantee the uniformity of gas mixing.

[0018] In summary, to address the aforementioned problems in existing technologies: 1. The mixing efficiency of natural gas and hydrogen is low, and the mixing speed is slow. 2. The manufacturing cost of the device is high, requiring power to drive the mixing of natural gas and hydrogen, thus consuming additional energy. Summary of the Invention

[0019] To overcome the shortcomings and defects of existing technologies, a natural gas hydrogenation mixer is provided to effectively solve the problems of low mixing efficiency, complex pipelines and inconvenient operation and maintenance in the natural gas hydrogenation process; to solve the problems of high resistance and easy blockage in existing technology equipment; and to solve the problems of large size and high manufacturing cost of existing technology devices.

[0020] To achieve the above objectives, the technical solution provided by this invention is as follows: A natural gas hydrogenation mixer includes an ellipsoidal shell. An inlet pipe and an outlet pipe are fixedly connected to the shell along its long axis. An inlet bellows is fixedly connected to the outlet end of the inlet pipe, located inside the shell. An outlet bellows is fixed inside the outlet pipe, with one end extending into the shell. A sealing plate is fixed to one end of the outlet bellows inside the shell, blocking one end of the outlet bellows. A gap is provided between the outer edge of the outlet bellows and the inner edge of the outlet pipe. Multiple air holes are provided on the expansion joints of the outlet bellows portion inside the shell. The sum of the flow areas of all air holes is greater than or equal to the flow area of ​​the outlet bellows. The center of the outlet end of the inlet bellows and the center of the sealing plate coincide with two focal points along the long axis of the shell, respectively. Both the inlet and outlet bellows are concentric with the long axis of the shell. The inlet pipe is connected to a gas swirl assembly.

[0021] Specifically, the gas swirl assembly includes a gas distribution assembly fixed inside the inlet pipe; the gas distribution assembly includes a central pipe fixed inside the inlet pipe, an annular cavity concentrically formed on the outer side of the central pipe, and multiple nozzles evenly distributed and fixed on the circumference of the central pipe, the inlet end of the nozzles communicating with the annular cavity, the outlet end of the nozzles communicating with the central pipe, the outlet ends of the nozzles tilting in the same direction of rotation, the axis of the nozzles making an angle of 30° with the corresponding longitudinal plane, and a hydrogen pipe fixed on the central pipe, one end of the hydrogen pipe communicating with the annular cavity, and the other end of the hydrogen pipe extending to the outer side of the inlet pipe. Specifically, the upper end of the inlet pipe is fixedly and sealed with an upper connector, an inner block is fixed inside the upper connector, a vertical pipe is fixed on the inner block, and multiple rotating blades are evenly distributed and fixed on the upper circumference of the vertical pipe.

[0022] Specifically, the rotation direction of the rotating blades is consistent with the rotation and spray direction of the nozzle.

[0023] Specifically, the gas swirling assembly includes a conical sleeve, the lower end of which is fixedly connected to the inlet pipe. An inner ring is concentrically fixed inside the conical sleeve, and an inner tube is concentrically slidably and sealed inside the inner ring. A locking sleeve is fixed at the upper end of the conical sleeve, and the upper end of the inner tube passes through the locking sleeve. The inner tube and the locking sleeve are slidably and sealed together. A locking nut is threaded onto the locking sleeve. After the locking nut is screwed in, the locking sleeve can clamp and fix the inner tube. There is an annular gap between the lower end of the inner tube and the inner wall of the conical sleeve. Multiple rotating pulsed jet heads are evenly distributed around the circumference of the inner ring. The outlet ends of the rotating pulsed jet heads are inclined in the same rotation direction and then inclined downward. Multiple vortex holes are evenly distributed around the circumference of the inner tube below the inner ring. The extension direction of the vortex holes is the tangential direction of the corresponding position of the inner tube. A side tube is fixedly connected in the tangential direction on one side of the upper end of the conical sleeve.

[0024] Specifically, the tangential swirling direction of the vortex orifice is consistent with the rotational jet direction of the rotating jet head.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This technical solution induces self-excited low-frequency oscillations through a unique structural design, generating periodic pressure fluctuations alternating between high-pressure and low-pressure zones, thereby creating intense vortices and turbulence within the shell cavity. This forces the natural gas and hydrogen streams to collide and intersect in space, breaking down stratification or enrichment phenomena caused by density differences and achieving molecular-level permeation. The introduced vortex orifices and rotating pulsed injectors enhance the shear effect through tangential swirling and pulsed injection, reducing molecular clusters during the premixing stage and ensuring more uniform mixing in subsequent stages. Mass transfer efficiency is significantly improved without external intervention, enabling the mixed gases to achieve uniform mixing at the microscale and avoiding the mixing inhomogeneity problems commonly found in traditional mixers.

[0026] 2. This technical solution utilizes the kinetic energy of the gas itself for propulsion, requiring no external energy input. The vibration energy generated by the high-speed rotating airflow impacting the sealing plate is converted into fluid pressure energy through mechanical vibration, forming a closed-loop self-excited oscillation. Simultaneously, the vibration frequency dynamically adjusts with the gas flow rate and ratio, ensuring stable operation under various working conditions. The locking sleeve and locking nut design further enhances adaptability, allowing manual adjustment of the inner tube position to optimize premixing, demonstrating the system's self-adaptability. This not only reduces energy consumption but also improves the equipment's applicability under varying working conditions, making it suitable for dynamic operation requirements in actual industrial scenarios. Furthermore, this technical solution also features an additional function of condensate hammer suppression structure and system. Condensate hammer is easily generated in gas pipelines. In winter, low temperatures lead to liquid accumulation in the pipelines, making condensate hammer formation more likely. When it occurs, it generates huge pressure fluctuations, posing a significant hazard. Existing technologies are relatively scarce in effectively suppressing the generation of condensate hammer or effectively suppressing and mitigating existing condensate hammer. This technical solution effectively reduces the intensity of condensate hammer at different locations, suppresses the formation of large independent bubbles, and inhibits the generation of large condensate hammers. When small condensate hammers occur, the airflow carries the liquid backflow. The corrugated outlet pipe with vents inside the shell, in conjunction with the shell, reduces the flow velocity of the backflowing fluid, effectively reducing the impact force and further reducing the intensity of condensate hammers. Simultaneously, it suppresses the generation of condensate hammers at different locations throughout the pipeline.

[0027] 3. Through the design of the sealing plate, corrugated pipe vents, and gaps, the system forces gas to flow along a specific path, extending the gas residence time within the casing and avoiding local dead zones. The rotating blades and nozzles work together to create shear layer mixing and spatial cross-modes, increasing the beneficial residence time and mixing space of the gas within the mixing chamber. Simultaneously, the periodic contraction or expansion of the vents during vibration generates high-frequency shearing action, cutting the gas stream and generating microscale vortices, further improving mixing uniformity. This design ensures uniform gas distribution and smooth transition, maximizing the use of the casing cavity as a highly efficient mixing chamber, promoting diffusion and molecular-level mixing.

[0028] 4. The sealing plate provides mechanical support, ensuring that the outflow bellows is concentric with the long axis of the housing, optimizing the hydrodynamic environment; the cone sleeve and inner ring design integrate the premixing and main mixing stages, reducing the need for additional equipment. All vibration and mixing mechanisms originate from internal gas flow, eliminating the need for complex drive devices, thus reducing system complexity, manufacturing costs, and maintenance frequency.

[0029] 5. Hydrogen gas enters the large end of the cone sleeve via a tangential swirling air intake. This side-entry method avoids a direct airflow impact on the rotating pulsating injector when the valve opening suddenly increases the intake volume, thus protecting the rotating pulsating injector. Simultaneously, the swirling flow generates a rotating impeller within the injector whose rotation changes with the velocity and pressure of the incoming hydrogen gas, resulting in smoother impeller startup and speed changes. This ensures stable and efficient operation of the integrated rotating pulsating injector. This invention induces a superimposed swirling and pulsating flow within the tube cavity, generating periodic pressure fluctuations alternating between high-pressure and low-pressure zones. This creates intense eddies and turbulence within the shell cavity, resulting in a highly efficient pressure-driven shear layer mixing mode and a highly efficient pulsating mass transfer effect.

[0030] 6. As a core mixing component, this invention effectively improves the problems of poor mixing uniformity and large pressure drop loss in traditional SK-type mixers, and can be applied to hydrogen blending in natural gas pipelines and skid-mounted natural gas hydrogen blending systems. This invention also provides additional vibration reduction and noise reduction during the mixing process.

[0031] 7. This invention can also be used as a mixing component for two core media. That is, it is not limited to the mixing of two gases. For gas-liquid and liquid-liquid mixing, this invention can also achieve the technical requirement of uniform mixing, and the mixing speed is fast and the efficiency is high. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of Example 1.

[0033] Figure 2 This is a cross-sectional view of the upper structure of the outflow bellows.

[0034] Figure 3 This is a cross-sectional view of the valve train assembly.

[0035] Figure 4 This is a schematic diagram of Example 2.

[0036] Figure 5 This is a schematic diagram of Example 3.

[0037] Figure 6 This is a schematic diagram of the cross-section of multiple vortex holes on the inner tube.

[0038] The components in the attached diagram are named as follows: 1. Housing, 2. Inlet pipe, 3. Outlet pipe, 4. Inlet bellows, 5. Outlet bellows, 6. Air hole, 7. Gas distribution assembly, 701. Central pipe, 702. Annular cavity, 703. Nozzle, 704. Hydrogen pipe, 8. Upper connector, 9. Inner block, 10. Vertical pipe, 11. Rotating blade, 12. Conical sleeve, 13. Inner pipe, 14. Vortex hole, 15. Inner ring, 16. Rotating pulsating injection head, 17. Locking sleeve, 18. Locking nut, 19. Side pipe, 20. Sealing plate. Detailed Implementation

[0039] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0040] Example 1: Refer to Figures 1-3 As shown, a natural gas hydrogenation mixer includes an ellipsoidal shell 1. The shell 1 is fixedly connected to an inlet pipe 2 and an outlet pipe 3 along its long axis. The outlet end of the inlet pipe 2 is fixedly connected to an inlet corrugated pipe 4, which is located inside the shell 1. An outlet corrugated pipe 5 is fixed inside the outlet pipe 3. One end of the outlet corrugated pipe 5 extends into the shell 1. A sealing plate 20 is fixed to one end of the outlet corrugated pipe 5 inside the shell 1, which blocks one end of the outlet corrugated pipe 5 inside the shell 1. A gap is provided between the outer edge of the outlet corrugated pipe 5 and the inner edge of the outlet pipe 3.

[0041] Multiple air holes 6 are provided on the expansion joint of the outflow bellows 5 section inside the housing 1. The sum of the flow areas of all the air holes 6 is greater than or equal to the flow area of ​​the outflow bellows 5. The center of the outlet end of the inflow bellows 4 and the center of the sealing plate 20 coincide with the two focal points in the long axis direction of the housing 1, respectively. Both the inflow bellows 4 and the outflow bellows 5 are concentric with the long axis of the housing 1. The inlet pipe 2 is connected to the gas swirl assembly.

[0042] The gas swirl assembly includes a gas distribution assembly 7, which is fixed inside the inlet pipe 2. The gas distribution assembly 7 includes a central pipe 701, which is fixed inside the inlet pipe 2. An annular cavity 702 is concentrically formed on the outer side of the central pipe 701. Multiple nozzles 703 are evenly distributed and fixed on the circumference of the central pipe 701. The inlet end of the nozzle 703 is connected to the annular cavity 702, and the outlet end of the nozzle 703 is connected to the central pipe 701. The outlet end of the nozzle 703 is inclined in the same rotation direction. The axis of the nozzle 703 makes an angle of 30° with the corresponding longitudinal plane. A hydrogen pipe 704 is fixed on the central pipe 701. One end of the hydrogen pipe 704 is connected to the annular cavity 702, and the other end of the hydrogen pipe 704 extends to the outer side of the inlet pipe 2.

[0043] During operation, natural gas enters through inlet pipe 2, and hydrogen enters through hydrogen pipe 704. After being ejected from nozzle 703, the hydrogen rotates and enters into inlet pipe 2. Through the inlet bellows 4, the mixing of natural gas and hydrogen creates a rotating flow, which in turn causes the inlet bellows 4 to vibrate. The nozzle 703 ejects hydrogen, causing the mixture of natural gas and hydrogen to rotate within the flow space of inlet pipe 2. The high-speed rotating airflow has downward impact kinetic energy and rotational kinetic energy. When this high-speed airflow with impact kinetic energy and rotational kinetic energy flows through the folds of the inlet bellows 4, it causes the inlet bellows 4 to become unstable, resulting in vibration and swaying. This causes the mixture of hydrogen and natural gas to sway and be ejected. This swaying and ejection at the first focal point along the long axis of the shell 1 causes the central jet to randomly sway along the long axis of the inner cavity of the shell 1. The central jet strikes the sealing plate 20 at the upper end of the outlet bellows 5, causing the outlet bellows 5 to sway. Due to uneven impact on the sealing plate 20, the outflow bellows 5 vibrates, causing the inflow bellows 4 and outflow bellows 5 to interact and resonate. This creates an expansion and contraction within the shell 1, resulting in periodic pressure fluctuations and turbulence in the mixed gas flow. Alternating high-pressure and low-pressure zones are generated, leading to more eddies within the shell 1 and increasing the turbulence of the mixed gas. This significantly increases the mass transfer coefficient, thus promoting the mixing of hydrogen and natural gas. In other words, the fluid medium within the shell 1 generates self-excited low-frequency oscillations, enabling the natural gas and hydrogen to achieve self-mixing.

[0044] The vibration of the inlet bellows 4 first premixes the natural gas and hydrogen. Due to the large density difference between natural gas and hydrogen, coupled with the unique structure and function of the inner cavity of the shell 1, the flow streams of natural gas and hydrogen are forced to intersect, causing collisions between the fluid streams, which facilitates the natural gas and hydrogen to mix evenly on their own.

[0045] After the natural gas and hydrogen are mixed evenly, they enter the outflow corrugated pipe 5 through the gas hole 6 and are discharged through the outlet pipe 3.

[0046] The sealing plate 20 on the outflow bellows 5 acts as a physical barrier, blocking one end of the outflow bellows 5 inside the shell 1. This forces the mixed gas to change direction and enter the outflow bellows 5 through the vent 6 on the expansion joint, thereby optimizing the flow path, extending the residence time of the gas in the shell 1, and, in conjunction with the gap design between the outer edge of the outflow bellows 5 and the inner edge of the outlet pipe 3, avoiding local dead zones and ensuring uniform gas distribution and a smooth transition to the outlet. The sealing plate 20 is located at the focal point along the long axis of the shell 1, becoming the impact point of the high-speed rotating mixed gas ejected from the inflow bellows 4. Due to the random swaying of the jet, the sealing plate 20 experiences uneven force, inducing periodic swaying and vibration of the outflow bellows 5. This vibration resonates with the vibration of the inflow bellows 4, amplifying the pressure fluctuations in the inner cavity of the shell 1 (alternating between high-pressure and low-pressure areas), promoting turbulence and eddy current generation, significantly improving the mass transfer efficiency of hydrogen and natural gas, and overcoming the mixing problem caused by the density difference between the two. The sealing plate 20 provides mechanical support to ensure that the outflow bellows 5 is concentric with the long axis of the shell 1, stabilizing the structure while optimizing the fluid dynamics environment. It utilizes the acoustic characteristics of the ellipsoid (focus energy concentration effect) to enhance self-excited low-frequency oscillation, achieving a highly efficient and energy-saving mixing process without external drive.

[0047] The outflow bellows 5 and the sealing plate 20 form a spring oscillator system. The sealing plate 20, impacted by the high-speed rotating airflow, generates periodic oscillating vibrations, which resonate with the inflow bellows 4, causing low-frequency pressure fluctuations within the shell 1. This oscillation results in alternating high-pressure and low-pressure zones, with repeated compression and expansion of the gas volume, generating intense eddies. The interlacing and collision of the flow streams forces the molecular-level permeation of natural gas and hydrogen, which have significant density differences, thus improving mass transfer efficiency. The vibrational energy directly acts on the fluid micro-particles, breaking the stratification trend of hydrogen rising and natural gas sinking, enabling forced mixing of the two phases at the microscale, avoiding the problem of light phase enrichment in traditional static mixers.

[0048] The energy of the vibration of the sealing plate 20 comes entirely from the impact kinetic energy of the airflow itself, which is converted into fluid pressure energy through mechanical vibration to form a closed loop. The vibration frequency of the sealing plate 20 is dynamically adjusted according to the gas flow rate and ratio. At high flow rates, the amplitude increases, and the eddy current intensity increases accordingly. At low flow rates, it maintains the basic, natural frequency oscillation to ensure mixing stability. (This natural frequency is related to factors such as the size and shape of the inner cavity of the shell 1, the stiffness, length, and diameter of the outflow bellows 5, and the mass of the sealing plate 20.) The sealing plate 20 is precisely positioned at a focal point of the housing 1, amplifying the energy of the randomly deflecting jet.

[0049] When the outflow bellows 5 vibrates, the diameter of the pores 6 changes. The pores 6 periodically contract or expand with the vibration, generating a high-frequency shearing effect on the passing mixed gas. The edge of the pores 6 forms an instantaneous high-speed jet, cutting the gas stream and generating microscale vortices that break up the natural gas and hydrogen molecule clusters, thereby increasing the turbulent kinetic energy and further improving the mixing uniformity.

[0050] The change in the diameter of pore 6 is synchronized with the pressure fluctuation in the inner cavity of shell 1. When it contracts, it reflects the pressure wave, enhancing the standing wave effect in the cavity of shell 1; when it expands, it releases gas, forming a low-pressure suction zone, accelerating fluid renewal.

[0051] Example 2: Based on Example 1, referring to... Figure 4 As shown, an upper connector 8 is fixedly and sealed to the upper end of the inlet pipe 2. An inner block 9 is fixed inside the upper connector 8, and a riser 10 is fixed on the inner block 9. Multiple rotating blades 11 are evenly distributed and fixed on the upper circumference of the riser 10. The rotation direction of the rotating blades 11 is consistent with the rotation and spray direction of the nozzle 703.

[0052] Natural gas flowing through the upper connector 8 rotates under the action of multiple rotating blades 11. Hydrogen gas is ejected from multiple nozzles 703 and rotates in the inlet pipe 2. Due to the velocity difference between natural gas and hydrogen, the high-speed rotating hydrogen carries the low-speed rotating natural gas, forming a shear layer between the natural gas and hydrogen. A velocity gradient exists on the cross-section, and natural gas and hydrogen are subjected to lateral shear forces. When natural gas and hydrogen are ejected and dispersed from the first focal point of the shell 1, a pressure shear flow is formed, that is, a mixing mode within the shear layer is formed. After reflection and refraction, the flow streams of natural gas and hydrogen simultaneously form spatial intersections, and a shear gradient mixing mode also exists. The two mixing modes superimpose and interact with each other, making the inner cavity of the shell 1 a true mixing chamber, increasing the beneficial residence time and mixing space of natural gas and hydrogen. The disturbance of the outflow bellows 5 further creates favorable conditions for the mixing of the two gases, allowing natural gas and hydrogen more time to diffuse and mix, thereby improving the uniformity of the mixed gas and helping to optimize the quality of the mixed gas.

[0053] The rotation direction of the rotating blade 11 is consistent with the rotation and spray direction of the nozzle 703 to promote and enhance the generation of the rotating flow. This rotating flow flows downward into the inner cavity of the inlet bellows 4, ensuring that the inlet bellows 4 can vibrate.

[0054] The combined rotation of the natural gas and hydrogen gas streams facilitates premixing of the two gases. When the mixed gas exits the inlet bellows 4, the space suddenly expands, the pressure decreases, and a jet forms at the inlet of the bellows 4. This jet at the first focal point of the inlet of the bellows 4 further promotes the dispersion and emission of some of the mixed gas into a central jet stream. Due to the significant density difference between natural gas and hydrogen, this unique structure and function of the inner cavity of the shell 1 forces the natural gas and hydrogen streams with different jet kinetic energies to intersect and collide, causing turbulent flow in the mixed gas and enhancing the mixing effect. This allows the natural gas and hydrogen to mix spontaneously and achieve a homogeneous mixture.

[0055] Example 3: Based on Example 1, referring to... Figure 5 and Figure 6 As shown, the gas swirl assembly includes a conical sleeve 12, the lower end of which is fixedly connected to the inlet pipe 2. An inner ring 15 is concentrically fixed inside the conical sleeve 12, and an inner tube 13 is concentrically and slidably and sealed inside the inner ring 15. A locking sleeve 17 is fixed to the upper end of the conical sleeve 12, and the upper end of the inner tube 13 passes through the locking sleeve 17. The inner tube 13 and the locking sleeve 17 are slidably and sealed together. A locking nut 18 is threaded onto the locking sleeve 17. After the locking nut 18 is screwed in, the locking sleeve 17 can clamp and fix the inner tube 13. There is an annular seam between the lower end of the inner tube 13 and the inner wall of the cone sleeve 12. Multiple rotating pulsed jet heads 16 are evenly distributed and fixed on the inner ring 15. The outlet end of the rotating pulsed jet head 16 is tilted in the same rotation direction and then tilted downward. Multiple vortex holes 14 are evenly distributed on the inner tube 13 below the inner ring 15. The extension direction of the vortex hole 14 is the tangential direction of the corresponding position of the inner tube 13. The tangential swirling direction of the vortex hole 14 is consistent with the rotational jet direction of the rotating jet head.

[0056] A side tube 19 is fixedly connected to one side of the upper end of the cone sleeve 12 in the tangential direction.

[0057] In this embodiment, hydrogen enters the conical sleeve 12 from the side pipe 19. After entering the conical sleeve 12, the hydrogen rotates at high speed around the inner pipe 13. Natural gas is introduced into the inner pipe 13. A portion of the hydrogen rotating around the inner pipe 13 enters the inner pipe 13 tangentially along the tangential direction of the inner pipe 13 through multiple vortex holes 14 on the inner pipe 13. The hydrogen entering the inner pipe 13 is pre-mixed with the natural gas in the inner pipe 13. Most of the hydrogen flows out at high speed through the annular gap between the lower end of the inner pipe 13 and the inner wall of the conical sleeve 12, and then enters the shell 1 to mix with the natural gas in the shell 1.

[0058] A highly efficient premixing mechanism is achieved through the synergistic effect of the vortex orifice 14 and the annular gap. After hydrogen enters the conical sleeve 12 from the side pipe 19, a portion of the hydrogen enters the inner pipe 13 tangentially through multiple vortex orifices 14, forming preliminary mixing with the natural gas flowing in the inner pipe 13. The premixing utilizes the turbulent shear force generated by the tangential swirling flow to break up the molecular clusters between hydrogen and natural gas in advance, reducing stratification caused by density differences and laying a uniform foundation for subsequent mixing. At the same time, most of the hydrogen flows out at high speed through the annular gap between the lower end of the inner pipe 13 and the inner wall of the conical sleeve 12. This high-speed rotating flow generates strong vortices and shear layers in the shell 1, which not only increases the relative velocity and contact area between the gases, but also enhances the pulse jet effect through the directional tilting design of the rotating pulsed injector 16. This results in a dynamic, highly turbulent flow of the mixed gas in the inner cavity of the shell 1, effectively prolonging the residence time of the gas in the mixing cavity, thereby improving the efficiency of diffusion and molecular-level penetration.

[0059] The tangential swirling direction of the vortex orifice 14 is consistent with the rotating injection direction of the rotating pulsed injector 16, ensuring the coordination and consistency of the flow path and avoiding energy loss and the formation of local dead zones. Utilizing the pulse characteristics of the rotating pulsed injector 16, combined with the kinetic energy of the high-speed rotating hydrogen gas flow, alternating high and low pressure zones are generated in the inner cavity of the shell 1, further amplifying the intensity of vortices and turbulence. This causes the natural gas and hydrogen streams to collide and intersect in space, enhancing the shear gradient and reflection effects, thereby overcoming the common problem of light phase (hydrogen) rising and heavy phase (natural gas) sinking in traditional mixers. In addition, the mechanical design of the locking sleeve 17 and locking nut 18 provides high adjustability and sealing. Users can fix the position of the inner tube 13 by screwing in the locking nut 18 to adapt to different flow rates and ratios, ensuring that the system can maintain stable mixing performance under varying operating conditions without relying on an external drive source, demonstrating energy-saving and adaptive characteristics.

[0060] This embodiment optimizes the overall mixing path by integrating the premixing and main mixing stages. The downward tilt angle of the rotating pulsed injector 16, combined with the tangential flow of the vortex orifice 14, forms a multi-stage mixing mode: in the premixing stage, hydrogen enters the inner tube 13 from the vortex orifice 14 and is initially mixed with natural gas; in the main mixing stage, the high-speed rotating hydrogen flows out from the annular gap and undergoes secondary collision and diffusion with natural gas within the shell 1. This staged processing not only reduces mixing energy consumption but also enhances the self-excited oscillation effect within the shell 1 cavity through the periodic pressure fluctuations induced by pulse injection, making the mixing process more uniform and thorough. This embodiment has significant advantages in improving mixing quality, adaptability, and energy efficiency, and is particularly suitable for high-proportion hydrogen mixing scenarios. It can effectively solve the common problem of uneven mixing in natural gas hydrogenation applications, while simplifying system complexity and reducing maintenance requirements.

[0061] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A natural gas hydrogenation mixer, comprising an ellipsoidal shell (1), wherein an inlet pipe (2) and an outlet pipe (3) are fixedly connected to the shell (1) along its long axis, characterized in that, The outlet end of the inlet pipe (2) is fixedly connected to the inlet bellows pipe (4), which is located inside the shell (1). The outlet pipe (3) is fixedly connected to the outlet bellows pipe (5), one end of which extends into the shell (1). A sealing plate (20) is fixed to one end of the outlet bellows pipe (5) inside the shell (1), which blocks one end of the outlet bellows pipe (5) inside the shell (1). A gap is provided between the outer edge of the outlet bellows pipe (5) and the inner edge of the outlet pipe (3). The expansion joint of the outflow bellows (5) in the shell (1) is provided with multiple air holes (6). The sum of the flow areas of all the air holes (6) is greater than or equal to the flow area of ​​the outflow bellows (5). The center of the outlet end of the inflow bellows (4) and the center of the sealing plate (20) coincide with the two focal points in the long axis direction of the shell (1). The inflow bellows (4) and the outflow bellows (5) are both concentric with the long axis of the shell (1). The inlet pipe (2) is connected to the gas swirl assembly.

2. The natural gas hydrogenation mixer according to claim 1, characterized in that, The gas swirl assembly includes a gas distribution assembly (7), which is fixed inside the inlet pipe (2). The gas distribution assembly (7) includes a central pipe (701), which is fixed inside the inlet pipe (2). An annular cavity (702) is concentrically opened on the outside of the central pipe (701). Multiple nozzles (703) are evenly distributed and fixed on the circumference of the central pipe (701). The inlet end of the nozzle (703) is connected to the annular cavity (702), and the outlet end of the nozzle (703) is connected to the central pipe (701). The outlet end of the nozzle (703) is inclined in the same rotation direction. The axis of the nozzle (703) makes an angle of 30° with the corresponding longitudinal plane. A hydrogen pipe (704) is fixed on the central pipe (701). One end of the hydrogen pipe (704) is connected to the annular cavity (702), and the other end of the hydrogen pipe (704) extends to the outside of the inlet pipe (2).

3. The natural gas hydrogenation mixer according to claim 2, characterized in that, The upper end of the inlet pipe (2) is fixedly sealed with an upper connector (8), an inner block (9) is fixed inside the upper connector (8), a riser pipe (10) is fixed on the inner block (9), and multiple rotating blades (11) are evenly distributed around the upper end of the riser pipe (10).

4. The natural gas hydrogenation mixer according to claim 3, characterized in that, The rotation direction of the rotating blade (11) is consistent with the rotation and spraying direction of the nozzle (703).

5. The natural gas hydrogenation mixer according to claim 1, characterized in that, The gas swirl assembly includes a conical sleeve (12), the lower end of which is fixedly connected to the inlet pipe (2). An inner ring (15) is concentrically fixed inside the conical sleeve (12), and an inner tube (13) is concentrically slidably and sealed inside the inner ring (15). A locking sleeve (17) is fixed at the upper end of the conical sleeve (12), and the upper end of the inner tube (13) passes through the locking sleeve (17). The inner tube (13) and the locking sleeve (17) are slidably and sealed together. A locking nut (18) is threaded onto the locking sleeve (17). After the locking nut (18) is screwed in, the locking sleeve (17) can be clamped and fixed. The inner tube (13) has an annular seam between its lower end and the inner wall of the cone sleeve (12). Multiple rotating pulsed jet heads (16) are evenly distributed and fixed on the inner ring (15). The outlet end of the rotating pulsed jet head (16) is tilted in the same rotation direction and then tilted downward. Multiple vortex holes (14) are evenly distributed on the inner tube (13) below the inner ring (15). The extension direction of the vortex holes (14) is the tangential direction of the corresponding position of the inner tube (13). A side tube (19) is fixedly connected to the tangential direction on one side of the upper end of the cone sleeve (12).

6. The natural gas hydrogenation mixer according to claim 5, characterized in that, The tangential swirling direction of the vortex orifice (14) is consistent with the rotational jetting direction of the rotating jet head.

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