CN220558944U

CN220558944U - Natural gas hydrogen-adding device

Info

Publication number: CN220558944U
Application number: CN202322065991.9U
Authority: CN
Inventors: 陈李斌; 王利畏; 赵林昌; 尚德彬; 高继峰; 仵俊伟; 田中央; 王志会; 胡纪军; 汪波
Original assignee: Sinopec Oilfield Service Corp; Sinopec Zhongyuan Petroleum Engineering Design Co Ltd
Current assignee: Sinopec Oilfield Service Corp; Sinopec Zhongyuan Petroleum Engineering Design Co Ltd
Priority date: 2023-08-02
Filing date: 2023-08-02
Publication date: 2024-03-08
Anticipated expiration: 2033-08-02

Abstract

The utility model discloses a natural gas hydrogen-adding device, which relates to the technical field of gas filling equipment, in particular to a natural gas hydrogen-adding device, comprising an outer layer pipe and an inner layer pipe, wherein the inner layer pipe penetrates through one end of the outer layer pipe and is fixedly connected with the outer layer pipe, and a corrugated pipe is arranged in the outer layer pipe; through the cooperation setting of inlayer pipe, bellows, inlayer pipe, this natural gas hydrogen loading device has had improved natural gas, hydrogen mixing efficiency and speed, and natural gas flows back to the backward flow chamber of bellows through inlayer pipe to natural gas enters into mixing chamber through the gas pocket on the bellows and mixes with hydrogen; under the atmospheric pressure effect of natural gas and hydrogen, the bellows takes place the vibration and causes the disturbance to two kinds of gases in the mixing chamber when the vibration, reinforces the mixing of natural gas and hydrogen, has reached the purpose that improves natural gas and hydrogen mixing efficiency, and the device overall structure that this application shows is simple, material low price, greatly reduced manufacturing cost.

Description

Natural gas hydrogen-adding device

Technical Field

The utility model relates to the technical field of gas filling equipment, in particular to a natural gas hydrogen-adding device.

Background

The mixed hydrogen natural gas is a mixed fuel which is obtained by adding 10-20% of hydrogen into natural gas in volume fraction, and is a kind of shallow hydrogen fuel. The natural gas hydrogen-mixed fuel has high combustion speed and high heat value, can obviously reduce carbon emission, and is favored by people.

The presently disclosed utility model issued patent "a multi-functional mixed gas station and filling method of natural gas and hydrogen" (CN 105090738B) discloses a high energy delivery gas and method of delivering the same for increasing the energy capacity of pipelines and other vessels designed to deliver natural gas in a compressed or liquefied state at ambient conditions. Methane and other gases are used as feedstock, methane from natural gas fields, coal beds or derived from the reaction of hydrogen with coal as a primary energy source. The method can provide a rich source for hydrogen production, but does not disclose the use of natural gas pipelines for conveying hydrogen, and has the problem of uniform mixing of two gases.

The existing high-pressure multifunctional gas station system for natural gas and hydrogen mainly comprises: the system comprises a natural gas supply system, a hydrogen gas supply system, at least one gas mixing and filling machine and a data acquisition and monitoring control (SCADA) system. The prior published utility model grants a patent "hydrogen delivery device" (CN 206669338U). The device comprises a hydrogen storage tank, a natural gas conveying section, a hydrogen injection section and a mixed gas conveying section; the hydrogen storage tank is used for supplying compressed hydrogen to the hydrogen injection section; the natural gas conveying section is used for conveying natural gas; the hydrogen injection section is used for receiving the hydrogen from the hydrogen storage tank and mixing the hydrogen with the natural gas from the natural gas conveying section to form a mixed gas; the mixed gas conveying section is used for conveying the mixed gas; the inner diameter of the hydrogen injection section is smaller than that of the natural gas conveying section, and the inner diameter of the hydrogen injection section is smaller than that of the mixed gas conveying section. The device modifies the existing natural gas pipeline so that it can be used for delivering hydrogen, thus being capable of delivering hydrogen at low cost. However, the mixing efficiency of the natural gas and the hydrogen changes along with the pressure change of the pipeline, the problem that the mixing of the two gases is not uniform enough can exist in a long distance in the pipeline, and the problem of uneven density caused by gas layering can occur in the pipeline transportation process. Because of the large density difference between natural gas and hydrogen, it is difficult for a general blending method to mix them rapidly and uniformly, if natural gas and hydrogen are mixed unevenly, the combustion stability of the mixed gas is affected, the control of combustion products is difficult, and pollutants such as nitrogen oxides and other harmful gases may be generated. Therefore, the proportion, uniformity and safety of the hydrogen added into the natural gas are required to be high, and the doping method is critical.

To sum up, in order to solve the problems existing in the prior art: 1. the mixing efficiency of natural gas and hydrogen is low, and the mixing speed is low. 2. The device has higher manufacturing cost, needs power to drive natural gas and hydrogen to mix, and consumes extra energy.

Disclosure of Invention

(one) solving the technical problems

Aiming at the defects of the prior art, the utility model provides a natural gas hydrogen loading device, which solves the problems in the background art.

(II) technical scheme

In order to achieve the above purpose, the utility model is realized by the following technical scheme: the utility model provides a natural gas hydrogen device that mixes, includes outer tube and inlayer pipe, the inlayer pipe runs through the one end of outer tube and rather than fixed connection, the inside of outer tube is provided with the bellows, the bellows cover is established the one end that the inner tube is located the outer tube, constitute the backward flow chamber between bellows and the inlayer pipe, the inside cavity and the backward flow chamber intercommunication of inlayer pipe, constitute the hybrid chamber between bellows and the outer tube, backward flow chamber and hybrid chamber intercommunication, be provided with at least one hydrogen pipeline interface on the outer tube, self-excitation oscillation cavity is installed to the gas outlet department of outer tube, the one end that the outer tube was kept away from to self-excitation oscillation cavity is installed down the nozzle body.

Optionally, both ends of outer tube are thick portion and detail respectively, the inlayer pipe runs through the thick portion place end of outer tube, the one end that the inlayer pipe kept away from the outer tube is provided with the natural gas line interface, the inlayer pipe is located the protruding form that the lateral wall of bellows inside part is outside extension.

Optionally, one end of the bellows is fixedly connected with the inner side wall of the end head of the thick portion of the outer layer tube, and a plurality of air holes are formed in the outer side wall of the bellows and near the end head of the thick portion of the outer layer tube.

Optionally, the hydrogen pipeline interface runs through and sets up on the lateral wall that is close to thick portion place end and rather than fixed connection of outer pipe, the hydrogen pipeline interface is located the inside one end port of outer pipe and is the chamfer form.

Optionally, the thick portion of outer pipe place end inside wall just is located the bellows internal connection floor, the floor is toper tube-shape and cover and establishes on the lateral wall of inlayer pipe, the one end and the lateral wall fixed connection of inlayer pipe of floor.

Optionally, the upper nozzle body is in threaded connection with the outer layer pipe at the gas outlet, one end of the upper nozzle body, which is far away from the gas outlet, is fixedly connected with the self-oscillation cavity, and the lower nozzle body is fixedly and hermetically arranged at one end of the self-oscillation cavity, which is far away from the upper nozzle body.

Optionally, the bore diameter of the self-oscillation cavity gradually becomes larger from one end close to the upper nozzle body to the other end, the maximum bore diameter of the bore of the self-oscillation cavity is 2.5 times of the minimum bore diameter, the self-oscillation cavity is a revolving body, and the bore of the self-oscillation cavity is an oscillation cavity.

Optionally, the hole diameters of the upper nozzle body and the inner hole of the lower nozzle body are consistent, the side wall of the lower nozzle body, which is close to one end of the upper nozzle body, is a collision wall, and the collision wall is positioned in the inner hole of the self-oscillation cavity.

Optionally, the collision wall of the lower nozzle body is in an inclined shape gradually protruding from the peripheral side to the central axis.

(III) beneficial effects

The utility model provides a natural gas hydrogen-adding device, which has the following beneficial effects:

1. according to the natural gas hydrogen-adding device, through the matching arrangement of the inner layer pipe, the corrugated pipe and the outer layer pipe, the natural gas hydrogen-adding device has the advantages that the mixing efficiency and speed of natural gas and hydrogen are improved, the natural gas flows back to the backflow cavity of the corrugated pipe through the inner layer pipe, and the natural gas enters the mixing cavity through the air holes on the corrugated pipe and is mixed with the hydrogen; wherein, under the atmospheric pressure effect of natural gas and hydrogen, the bellows takes place high-frequency oscillation and causes the disturbance to two kinds of gases in the mixing chamber when high-frequency oscillation, simultaneously, the bellow form on the bellows is protruding can effectively disturb and hinder the flow of gas, strengthens the mixing of natural gas and hydrogen, has reached the purpose that improves natural gas and hydrogen mixing efficiency, simultaneously, the device overall structure that this application shows is simple, material low price, greatly reduced manufacturing cost.

2. According to the natural gas hydrogen-adding device, through the matching arrangement of the self-oscillation pulse jet nozzle (the upper nozzle body, the self-oscillation cavity and the lower nozzle body), the natural gas hydrogen-adding device further has the effect of improving the mixing of hydrogen and natural gas after mixing, through the fixed installation of the self-oscillation cavity and the lower nozzle body, the self-oscillation cavity and the lower nozzle body form a whole, mixed gas (fluid) is converted into pulse flow after passing through the middle cavity of the self-oscillation cavity, the amplitude of the fluid pressure is improved by 15% -30%, the pulse frequency is increased from tens of hertz to hundreds of hertz, the turbulence characteristic of the fluid is greatly improved, the advantages of the pulse flow in the aspect of pipe flow drag reduction can be exerted, the energy consumption is saved, the cost of long-distance pipeline transportation is reduced, and the purposes of improving the mixing effect of the mixed gas and replacing power equipment to reduce the energy consumption cost are achieved.

3. The natural gas hydrogen-adding device has the advantages of simple integral manufacturing process, low cost and convenient installation and use; the device has small volume and small occupied area, and can effectively reduce the equipment investment cost.

Drawings

FIG. 1 is a schematic cross-sectional view of an inner tube of a natural gas loading device according to the present utility model;

FIG. 2 is a schematic cross-sectional view of a natural gas loading device according to the present utility model;

FIG. 3 is a schematic perspective view of an inner tube of a natural gas loading device according to the present utility model;

FIG. 4 is a schematic perspective view of a rib plate of a natural gas hydrogen loading device according to the present utility model;

fig. 5 is a schematic cross-sectional view of a self-oscillating cavity of a natural gas loading device according to the present utility model.

In the figure: 1. an inner layer tube; 2. a bellows; 3. air holes; 4. an outer layer tube; 5. rib plates; 6. a hydrogen pipeline interface; 7. a natural gas pipeline interface; 8. a lower nozzle body; 801. a collision wall; 9. self-oscillation cavity; 10. an air outlet; 11. and an upper nozzle body.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments.

Referring to fig. 1 to 5, the present utility model provides the following technical solutions: the utility model provides a natural gas hydrogen device, including outer tube 4 and inlayer pipe 1, inlayer pipe 1 runs through the one end of outer tube 4 and rather than fixed connection, the inside of outer tube 4 is provided with bellows 2, bellows 2 cover is established at the one end that inner tube 1 is located outer tube 4, constitute the backward flow chamber between bellows 2 and the inlayer pipe 1, the inside cavity and the backward flow chamber intercommunication of inlayer pipe 1, constitute the mixing chamber between bellows 2 and the outer tube 4, backward flow chamber and mixing chamber intercommunication, be provided with at least one hydrogen pipeline interface 6 on the outer tube 4, the gas outlet 10 department of outer tube 4 installs the upper nozzle body 11, the one end that the gas outlet 10 was kept away from to the upper nozzle body 11 is installed self-excitation oscillation cavity 9, the one end that the upper nozzle body 11 was kept away from to self-excitation oscillation cavity 9 is installed down the nozzle body 8.

The device can be used for being installed on the existing natural gas and hydrogen pipelines in an embedded mode. Natural gas flows into the reflux cavity from the middle cavity of the inner tube 1, and then flows into the mixing cavity through the air holes 3 on the corrugated tube 2. Hydrogen flows into the mixing chamber through the hydrogen line connection 6. The natural gas and the hydrogen gas are converged and mixed in the mixing chamber, and the mixed gas flows out through the gas outlet 10 of the outer tube 4 (refer to fig. 1 and 2, wherein the direction indicated by the arrow is the gas flowing direction). By installing the upper nozzle body 11, the self-oscillation cavity 9 and the lower nozzle body 8 at the air outlet 10 of the outer layer pipe, the mixed gas generates pulse flow when passing through the upper nozzle body 11, the self-oscillation cavity 9 and the lower nozzle body 8, the pulse flow can improve the flow characteristic of the bottom layer of the boundary layer of the pipe flow, and the rapid and high-efficiency uniform mixing of the natural gas and the hydrogen can be promoted; in terms of heat transfer and mass transfer, the pulse flow can also greatly improve the thermal efficiency, and the thermal efficiency can be improved by 10 percent. Meanwhile, the pulse flow can improve the deposition of paraffin in the transportation of the natural gas and hydrogen mixed pipeline. The resistance loss during gas transportation of the pipeline can be reduced, and the energy consumption is saved. The device comprehensively utilizes the self-oscillation mixing technology and the technical solution of high heat transfer and mass transfer efficiency of the pulse flow, so that the mixing efficiency is high, and the advantages of the pulse flow in the aspect of pipe flow drag reduction can be exerted, so that the cost of long-distance pipeline transportation can be reduced. The device has very important function and significance for establishing a hydrogen transportation network and popularizing a hydrogen fuel cell vehicle.

Specifically, the two ends of the outer tube 4 are a thick portion and a thin portion (the end where the air outlet 10 is located), the inner tube 1 penetrates the end where the thick portion of the outer tube 4 is located, the end of the inner tube 1 away from the outer tube 4 is provided with a natural gas pipeline interface 7 (for being in mounting communication with a natural gas supply pipeline), and the outer side wall of the inner portion of the inner tube 1 located in the corrugated tube 2 is in a protruding shape extending outwards.

The pipe wall of the inner layer pipe 1 is designed to be convex, so that the flow path of the natural gas in the backflow cavity can be disturbed, the natural gas is disturbed, and meanwhile, the natural gas is caused to impact the corrugated pipe 2 in the backflow cavity, and the corrugated pipe 2 is vibrated. The corrugated pipe 2 integrally vibrates, so that the disturbance can be caused to the gas in the backflow cavity and the mixing cavity, the layering of natural gas and hydrogen is avoided, the gas mixing effect of the mixing cavity is enhanced, and the gas mixing efficiency is improved.

Specifically, one end of the bellows 2 is fixedly connected with the inner side wall of the end head of the thick portion of the outer layer tube 4, and a plurality of air holes 3 are formed in the outer side wall of the bellows 2 and near the end head of the thick portion of the outer layer tube 4.

Wherein, each gas pocket 3 is regularly arranged and offered on the bellows 2, and is located the one end in backward flow chamber, and natural gas enters into the mixing chamber through each gas pocket 3 in backward flow intracavity, mixes with the hydrogen converging.

In particular, the bellows 2 has a certain toughness and can be stretched under the action of air pressure. The corrugated pipe 2 is preferably made of stainless steel pipes (the multi-stage stainless steel annular cylinders are assembled and installed to form the whole corrugated pipe 2, and the stainless steel annular cylinders at all stages locally shake under the action of air pressure to achieve the vibration effect).

Specifically, the hydrogen pipeline interface 6 is arranged on the outer side wall of the outer layer pipe 4 near the end where the thick part is located in a penetrating way and is fixedly connected with the outer side wall, and one end port of the hydrogen pipeline interface 6 positioned in the outer layer pipe 4 is in a bevel shape.

Wherein the hydrogen pipeline interface 6 is used for being communicated with the hydrogen inlet pipe in a mounting way. The outlet end of the hydrogen pipeline connector 6 is designed into an inclined notch shape, so that hydrogen can enter the mixing cavity and be stably mixed with natural gas, and the hydrogen can be quickly and uniformly mixed.

Specifically, the thick portion of outer tube 4 place the end inside wall and be located bellows 2 internal fixation and be connected with floor 5, floor 5 is toper tube-shape and cover and establish on the lateral wall of inlayer pipe 1, the one end of floor 5 and the lateral wall fixed connection of inlayer pipe 1.

Wherein the rib plates 5 are used for guiding natural gas. Natural gas flows in the backflow cavity, and then encounters the rib plate 5 after flowing to the tail end of the backflow cavity, and the natural gas flows are beneficial to turning to the direction of the air holes 3 and flowing out from each air hole 3 under the action of the inclined slope of the outer side wall of the rib plate 5, and when entering the external mixing cavity, the natural gas flows with pressure stabilization and current stabilization are converged with the hydrogen gas flows, the mixing path is lengthened, and uniform mixing is beneficial to.

Specifically, the upper nozzle body 11 is in threaded connection with the outer layer pipe 4 at the air outlet 10, one end of the upper nozzle body 11, which is far away from the air outlet 10, is fixedly connected with the self-oscillation cavity 9, and the lower nozzle body 8 is fixedly installed at one end of the self-oscillation cavity 9, which is far away from the upper nozzle body 11, in a sealing manner.

Further specifically, the bore diameter of the self-oscillation cavity 9 gradually becomes larger from one end close to the upper nozzle body 11 to the other end, the maximum bore diameter of the bore of the self-oscillation cavity 9 is 2.5 times of the minimum bore diameter, the self-oscillation cavity 9 is a revolution body, and the bore of the self-oscillation cavity 9 is an oscillation cavity. The self-excited oscillation cavity is a revolution body, the revolution body is provided with an inlet (the inlet end is communicated with the upper nozzle body 11) and an outlet (the outlet end is communicated with the lower nozzle body 8), the middle (namely an inner hole) is an oscillation cavity, and the symmetrical exponential surface cavity is a cavity structure with the complexity of boundary layer theory and vortex theory by virtue of the symmetrical exponential surface cavity (the inner contour curve of the revolution body is formed by sequentially and smoothly connecting an inward concave high-order square curve and a straight line segment).

More specifically, the upper nozzle body 11 has a diameter consistent with the diameter of the inner hole of the lower nozzle body 8, and the side wall of the lower nozzle body 8 near one end of the upper nozzle body 11 is a collision wall 801, and the collision wall 801 is positioned in the inner hole of the self-oscillation cavity 9. The collision wall of the lower nozzle body 8 is inclined gradually protruding from the outer periphery to the central axis (the included angle between the collision wall and the cross section of the hole where the collision wall is located can be 150 degrees, refer to fig. 5), that is, the collision wall 801 of the lower nozzle body 8 is conical.

Wherein, the inner holes of the upper nozzle body 11, the self-oscillation cavity 9 and the lower nozzle body 8 jointly form a self-oscillation cavity. The mixed gas enters the self-oscillation cavity 9 through the upper nozzle body 11, and the mixed gas is gradually dispersed and collided with the collision wall 801 of the lower nozzle body 8 to generate a vortex ring due to self-excitation as the inner hole of the self-oscillation cavity 9 gradually becomes larger, so that self-oscillation and efficient uniform mixing are realized. The uniformly mixed gas flows out from the middle hole of the lower nozzle body 8 in a pulse flow mode.

The device can solve the problem of uneven density caused by gas layering of the existing gas station. The existing gas station adopts a premixing technology, a storage tank of HCNG mixed gas is often needed, and the HCNG mixed gas can be layered to cause uneven density in the long-term storage process, and the combustion and emission characteristics of an automobile are affected after the HCNG mixed gas is filled into an HCNG vehicle. The device is used in a gas station, can be arranged in a gas station gas filling pipeline, and can convert incoming flow into pulse flow after passing through the self-excited oscillation cavity by means of the special shape and specific boundary conditions of the front end nozzle body, the self-excited oscillation cavity 9 and the lower nozzle body 8 under the condition that no additional auxiliary equipment is needed, and the amplitude of the outflow pressure is improved to (115-130)% of the incoming flow pressure, so that the mixing condition of gas is greatly improved, the convection and diffusion capacity of the gas is improved, the gas can be fully mixed in the self-excited oscillation mixing cavity, and the problem of uneven density caused by gas layering can be effectively solved.

When in use, the utility model is characterized in that: the device shown in the application can be used for being installed on the existing natural gas and hydrogen pipelines in an embedded mode.

1. Natural gas flows in from the middle cavity of the inner layer pipe 1, and after flowing in, the natural gas impacts the pipe bottom wall of the corrugated pipe 2 (the side wall of one end of the corrugated pipe 2 close to the air outlet 10), the corrugated pipe 2 deforms and stretches under the action of natural gas pressure, and the effects of stabilizing pressure and flow and eliminating vibration are achieved. The bottom of the bellows 2 blocks the air outlet 10 of the outer tube 4 when it is maximally extended. So that the elongation of the bellows 2 does not exceed its deformation range. When the machine stops to generate a reflux air hammer, when the shrinkage of the corrugated pipe 2 is maximum, the pipe bottom of the corrugated pipe is propped against the outlet end of the inner pipe 1, so that the shrinkage of the corrugated pipe 2 does not exceed the deformation range of the corrugated pipe. So arranged, it is advantageous to protect the bellows 2.

2. The natural gas continues to flow to the return chamber and flows into the mixing chamber through the respective gas holes 3. Hydrogen enters the mixing cavity through the hydrogen pipeline interface 6, and the hydrogen and the natural gas are mixed in the mixing cavity, so that the path is lengthened, and uniform mixing is facilitated. Meanwhile, the vibrating corrugated pipe 2 is used for disturbing the mixed gas, so that the gas is uniformly mixed.

3. After the hydrogen and the natural gas enter the mixing cavity, the air pressure in the mixing cavity and the air pressure in the reflux cavity are gradually balanced, and the mixed gas which is primarily mixed and uniformly mixed flows to the air outlet 10.

4. The mixed gas enters the self-oscillation cavity 9 through the upper nozzle body 11, and the mixed gas is self-excited to generate a vortex ring under the collision action of the collision wall 801 of the lower nozzle body 8 due to the gradual enlargement of the inner hole of the self-oscillation cavity 9, so that self-oscillation is realized. The air flow which is further evenly mixed is ejected from the middle hole of the lower nozzle body 8 in a pulse flow mode.

It is noted that the device disclosed in this application is not limited to application in the field of natural gas loading, but can be applied in the field of mixing other two (or more) fluids, and the related schemes disclosed in this application used when mixing other two (or more) fluids are all within the scope of protection of this scheme.

The present utility model is not limited to the above-mentioned embodiments, and any person skilled in the art, based on the technical solution of the present utility model and the inventive concept thereof, can be replaced or changed within the scope of the present utility model.

Claims

1. A natural gas hydrogen loading device, characterized in that: including inlayer pipe (4) and inlayer pipe (1), inlayer pipe (1) runs through the one end of inlayer pipe (4) and rather than fixed connection, the inside of inlayer pipe (4) is provided with bellows (2), bellows (2) cover is established in the one end that inlayer pipe (1) was located inlayer pipe (4), constitute the backward flow chamber between bellows (2) and inlayer pipe (1), the inside cavity and the backward flow chamber intercommunication of inlayer pipe (1), constitute the mixing chamber between bellows (2) and outer pipe (4), backward flow chamber and mixing chamber intercommunication, be provided with at least one hydrogen pipeline interface (6) on outer pipe (4), upper nozzle body (11) are installed in gas outlet (10) department of inlayer pipe (4), self-excited oscillation cavity (9) are installed to the one end that gas outlet (10) were kept away from to upper nozzle body (11), lower nozzle body (8) are installed to the one end that self-excited oscillation cavity (9) kept away from upper nozzle body (11).

2. A natural gas loading device as defined in claim 1, wherein: the two ends of the outer layer pipe (4) are thick parts and thin parts respectively, the inner layer pipe (1) penetrates through the end where the thick parts of the outer layer pipe (4) are located, one end, far away from the outer layer pipe (4), of the inner layer pipe (1) is provided with a natural gas pipeline interface (7), and the outer side wall of the inner part of the inner layer pipe (1) located in the corrugated pipe (2) is in an outwards extending protruding shape.

3. A natural gas loading device as defined in claim 1, wherein: one end of the corrugated pipe (2) is fixedly connected with the inner side wall of the end head of the thick part of the outer layer pipe (4), and a plurality of air holes (3) are formed in the outer side wall of the corrugated pipe (2) and close to the end head of the thick part of the outer layer pipe (4).

4. A natural gas loading device as defined in claim 1, wherein: the hydrogen pipeline interface (6) penetrates through the outer side wall of the end, close to the thick part, of the outer layer pipe (4) and is fixedly connected with the outer side wall, and one end port of the hydrogen pipeline interface (6) located inside the outer layer pipe (4) is in a bevel shape.

5. A natural gas loading device as defined in claim 1, wherein: the inner side wall of the end where the thick part of the outer layer pipe (4) is located is fixedly connected with a rib plate (5) which is in a conical cylinder shape and sleeved on the outer side wall of the inner layer pipe (1), and one end of the rib plate (5) is fixedly connected with the outer side wall of the inner layer pipe (1).

6. A natural gas loading device as defined in claim 1, wherein: the upper nozzle body (11) is in threaded connection with the outer layer pipe (4) at the air outlet (10), one end of the upper nozzle body (11) away from the air outlet (10) is fixedly connected with the self-oscillation cavity (9), and the lower nozzle body (8) is fixedly installed at one end of the self-oscillation cavity (9) away from the upper nozzle body (11) in a sealing mode.

7. The natural gas loading device of claim 6, wherein: the bore diameter of the self-oscillation cavity (9) is gradually increased from one end close to the upper nozzle body (11) to the other end, the maximum bore diameter of the bore of the self-oscillation cavity (9) is 2.5 times of the minimum bore diameter, the self-oscillation cavity (9) is a revolution body, and the bore of the self-oscillation cavity (9) is an oscillation cavity.

8. The natural gas loading device of claim 7, wherein: the upper nozzle body (11) and the lower nozzle body (8) have the same bore diameter, the side wall of one end of the lower nozzle body (8) close to the upper nozzle body (11) is a collision wall (801), and the collision wall (801) is positioned in the bore of the self-oscillation cavity (9).

9. The natural gas loading device of claim 8, wherein: the collision wall of the lower nozzle body (8) is inclined gradually protruding from the periphery to the central axis.