Natural gas hydrogen-doped mixing structure and mixing method

Abstract

The invention discloses a natural gas hydrogen-doped mixing structure and method, and relates to the technical field of natural gas hydrogen-doped mixing, the natural gas hydrogen-doped mixing structure comprises a natural gas main pipeline and a hydrogen incidence pipe which are connected with each other, the hydrogen incidence pipe comprises a straight pipe section and a spiral section, the spiral section is located in the natural gas main pipeline, and the straight pipe section is located outside the natural gas main pipeline; a plurality of gas outlets are formed in the spiral section of the hydrogen incident pipe, and a bulge is arranged between every two adjacent gas outlets. According to the natural gas hydrogen-doped mixing structure, natural gas and hydrogen can be mixed for three times in the using process, efficient, rapid and sufficient mixing of the natural gas and the hydrogen is facilitated, the mixing uniformity of the natural gas and the hydrogen is improved, and the risk of leakage of a hydrogen-doped natural gas pipeline is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen-doped natural gas mixing, and particularly relates to a hydrogen-doped natural gas mixing structure and a mixing method. BACKGROUND

[0002] Hydrogen-doped natural gas pipeline transportation has become one of the effective ways for large-scale and low-cost hydrogen energy transportation. The hydrogen-doped concentration of hydrogen-doped natural gas in the existing pipelines and demonstration projects in China has reached as high as 24%. A reasonable and advanced mixing method can ensure the uniformity of the mixing of natural gas and hydrogen. Especially for hydrogen and methane with large density difference, uneven mixing can easily cause stratification, which can cause the partial hydrogen partial pressure and volume fraction of the pipeline to increase, and further cause pipe failure and leakage. In order to reduce the safety risk of hydrogen-doped natural gas pipelines, natural gas and hydrogen need to be fully mixed.

[0003] There are mainly two ways for the pipeline transportation and mixing of hydrogen and natural gas. One is to directly inject hydrogen into the natural gas pipeline without any mixing device. The other is to use a gas mixing structure or device to fully mix natural gas and hydrogen. For the gas mixing method without mixing structure or device, experiments show that under the condition of low flow rate pipeline transportation, natural gas and hydrogen need to pass a distance of about 4000 times the diameter of the pipeline to be uniformly mixed. For long-distance pipelines with high flow rate, a distance of at least 100 times the diameter of the pipeline is needed to achieve uniform mixing, and the mixing uniformity cannot exceed 95% under some extreme conditions. Therefore, it is more beneficial to the mixing of hydrogen and natural gas to set a gas mixing structure or device.

[0004] At present, the technology for realizing hydrogen-doped natural gas by using a mixing structure or device is still in the experimental verification stage, and the hydrogen-doped natural gas mixing method is still in the exploration stage. Typical mixing structures include mechanical mixers, static mixers, and jet mixers, and need to be combined with supporting equipment and complex processes to realize the full mixing of natural gas and hydrogen. SUMMARY

[0005] Based on the problem of difficult full mixing of hydrogen-doped natural gas at present pointed out in the background, the purpose of the present application is to provide a hydrogen-doped natural gas mixing structure and a mixing method. The hydrogen-doped natural gas mixing structure can realize three times of mixing of natural gas and hydrogen during use, which is beneficial to the efficient, rapid and full mixing of natural gas and hydrogen, improves the uniformity of the mixing of natural gas and hydrogen, and reduces the risk of leakage of hydrogen-doped natural gas pipelines.

[0006] The present application is realized by the following technical solutions:

[0007] In a first aspect, this application provides a natural gas-hydrogen blending structure, including a natural gas main pipeline and a hydrogen injection pipe connected to each other. The hydrogen injection pipe includes a straight pipe section and a spiral section. The spiral section is located inside the natural gas main pipeline, and the straight pipe section is located outside the natural gas main pipeline. The spiral section of the hydrogen injection pipe is provided with a plurality of gas outlet holes, and a protrusion is provided between two adjacent gas outlet holes.

[0008] To prevent deformation and hydrogen corrosion or embrittlement of the helical section of the hydrogen injection tube, the helical section of the hydrogen injection tube can be made of high-strength and hydrogen-resistant stainless steel.

[0009] Furthermore, the natural gas main pipeline is provided with a through hole for installing the hydrogen injection pipe, and a straight section of the hydrogen injection pipe extends through the through hole to the outside of the natural gas main pipeline; a sealing component is installed at the through hole.

[0010] Furthermore, the sealing assembly includes an annular groove disposed on the wall of the through hole, a sealing ring installed in the annular groove, and an annular protrusion disposed on the straight section of the hydrogen injection pipe to engage with the annular groove.

[0011] Furthermore, a rotary connector is also connected to the straight section of the hydrogen injection pipe, and the straight section of the hydrogen injection pipe is rotatably connected to the main natural gas pipeline.

[0012] The helical section of the hydrogen injection tube can be rotated by rotating the connector. The rotational power can be generated by the gas flow of natural gas, or it can be driven by an external motor added to the connector.

[0013] Furthermore, the rotary connector includes a main connector and a secondary connector, and a bearing is provided between the main connector and the secondary connector. Both the main connector and the secondary connector are provided with an installation structure for installing pipes.

[0014] Furthermore, the mounting structure includes external threads disposed at the connecting ends of the main connector and the auxiliary connector.

[0015] Furthermore, both the main connector and the auxiliary connector have a slot at one end where the pipe is installed. A spring is installed in the slot. The pipe is installed on the main connector and the auxiliary connector by setting a locking block and an internal thread on the pipe that cooperate with the slot.

[0016] By installing a spring in the slot, when the pipe is threaded into place with the main connector and the auxiliary connector, the two ends of the spring always abut against the pipe and the rotary connector, making the connection between the pipe and the rotary connector tight. This makes the threaded end of the hydrogen injection pipe more stable when rotating, and the threaded connection also makes it less likely for the pipe and the rotating structure to fall off.

[0017] Furthermore, both the main connector and the auxiliary connector are provided with sealing grooves, and sealing blocks are installed on the pipeline to seal them to the main connector and the auxiliary connector.

[0018] By installing sealing structures at the connection points between the main and auxiliary connectors and the pipeline, the sealing performance can be improved, thus further preventing hydrogen leakage.

[0019] Furthermore, the diameter of the hydrogen injection pipe is less than 1 / 2 of the diameter of the main natural gas pipeline.

[0020] Setting the diameter of the hydrogen injection pipe to be smaller than half the diameter of the main natural gas pipeline can prevent the hydrogen injection pipe from blocking the main natural gas pipeline. At the same time, when the spiral section of the hydrogen injection pipe needs to rotate, its rotation will be more flexible.

[0021] Secondly, this application provides a method for mixing natural gas with hydrogen, using the above-mentioned hydrogen mixing structure. Specifically, natural gas is introduced into the main natural gas pipeline, and hydrogen is introduced into the hydrogen injection pipe. The natural gas and hydrogen are introduced simultaneously at the same flow rate. The hydrogen entering the spiral section of the hydrogen injection pipe is discharged from the outlet and fully mixes with the natural gas in the main natural gas pipeline.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] (1) The hydrogen-blended structure of natural gas in this application allows hydrogen to enter the spiral section through the straight section of the hydrogen injection pipe and then be discharged from the outlet to contact the natural gas in the main natural gas pipeline. This increases the contact area between hydrogen and natural gas and improves the mixing speed. At the same time, hydrogen mixes with natural gas from different directions, which increases the uniformity of the mixing of hydrogen and natural gas.

[0024] (2) This application also provides a protrusion on the spiral section of the hydrogen injection tube. The protrusion can increase the disturbance of hydrogen and natural gas, improve the mixing uniformity, which is equivalent to the effect of a second mixing, and further improves the mixing uniformity of hydrogen and natural gas.

[0025] (3) The spiral section of the hydrogen injection tube in this application can also play a disturbance role in the mixing of hydrogen and natural gas, which is conducive to the uniform mixing of hydrogen and natural gas, equivalent to the role of the third mixing, and further improves the mixing uniformity of hydrogen and natural gas.

[0026] (4) This application can avoid gas leakage by using a sealing component at the connection between the straight section of the hydrogen injection pipe and the main natural gas pipeline.

[0027] (5) In this application, a rotary connector is connected to the straight section of the hydrogen injection pipe. When natural gas flows, the airflow drives the spiral section of the hydrogen injection pipe to rotate, which strengthens the disturbance and can further increase the mixing speed and uniformity of hydrogen and natural gas. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings:

[0029] Figure 1 This is a schematic diagram of a hydrogen-doped natural gas hybrid structure according to Embodiment 1 of the present invention;

[0030] Figure 2 for Figure 1 Enlarged view of A in the middle;

[0031] Figure 3 This is a schematic diagram of a hydrogen-doped natural gas hybrid structure according to Embodiment 2 of the present invention;

[0032] Figure 4 This is a schematic diagram of a hydrogen-doped natural gas hybrid structure according to Embodiment 3 of the present invention;

[0033] Figure 5 This is a schematic diagram of the structure of the rotary connector connecting the pipe in Embodiment 3 of the present invention.

[0034] The attached diagram shows the markings and corresponding component names:

[0035] 01-Main natural gas pipeline, 02-Helical section, 03-Protrusion, 04-Gas outlet, 05-Straight pipe section, 06-Annular protrusion, 07-Annular groove, 08-Sealing ring, 09-Rotary connector, 10-Main connector, 11-Bearing, 12-Secondary connector, 13-External thread, 14-Slot, 15-Spring, 16-Sealing groove, 17-Sealing block, 18-Through hole, 19-Slot. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0037] Therefore, the detailed description of the embodiments of the present invention provided below is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] like Figure 1 and Figure 2 As shown, this embodiment provides a natural gas-hydrogen blending structure, including a natural gas main pipeline 01 and a hydrogen injection pipe connected to each other. The hydrogen injection pipe includes a straight pipe section 05 and a spiral section 02. The spiral section 02 is located inside the natural gas main pipeline 01, and the straight pipe section 05 is located outside the natural gas main pipeline 01. The spiral section 02 of the hydrogen injection pipe is provided with a plurality of gas outlet holes 04, and a protrusion 03 is provided between two adjacent gas outlet holes 04.

[0040] Specifically, the spiral section 02 of the hydrogen injection pipe is perpendicular to the main natural gas pipeline 01.

[0041] Specifically, to prevent gas leakage at the connection between the natural gas main pipeline 01 and the hydrogen injection pipe, the natural gas main pipeline 01 of the natural gas-hydrogen blending structure in this embodiment is provided with a through hole 18 for installing the hydrogen injection pipe. The straight pipe section 05 of the hydrogen injection pipe extends through the through hole 18 to the outside of the natural gas main pipeline 01. A sealing component is installed at the through hole 18. The sealing component includes an annular groove 07 provided on the hole wall of the through hole 18. A sealing ring 08 is installed in the annular groove 07. An annular protrusion 06 is provided on the straight pipe section 05 of the hydrogen injection pipe to engage with the annular groove 07.

[0042] Specifically, in order to prevent the hydrogen injection pipe from clogging the natural gas main pipeline 01, the diameter of the hydrogen injection pipe in this embodiment is less than 1 / 2 of the diameter of the natural gas main pipeline 01.

[0043] When mixing natural gas and hydrogen using the natural gas-hydrogen blending structure in this embodiment, natural gas is introduced into the main natural gas pipeline 01 at a flow rate of 10 m / s, while hydrogen is introduced from the straight section 05 of the hydrogen injection pipe at a flow rate of 10 m / s, and then enters the spiral section within the main natural gas pipeline 01. The hydrogen flows out from the outlet 04 and the tail of the spiral pipe into the main natural gas pipeline 01, where it comes into contact with and mixes with the natural gas. The flow rate at the hydrogen inlet can be adjusted appropriately according to the hydrogen blending ratio, which can be designed to be between 1% and 30%.

[0044] In particular, setting multiple outlet holes 04 in the spiral section of the hydrogen injection pipe can not only shorten the hydrogen discharge time and improve the efficiency of hydrogen discharge, but also quickly distribute hydrogen to multiple locations in the natural gas main pipeline 01, so that hydrogen and natural gas can quickly and fully contact each other, increase the contact area between hydrogen and natural gas, shorten the mixing time, and at the same time, hydrogen mixes with natural gas from different directions, increasing the mixing uniformity of hydrogen and natural gas, with a mixing uniformity of more than 98%.

[0045] Furthermore, the natural gas-hydrogen blending structure of this embodiment also features protrusions 03 on the spiral section 02 of the hydrogen injection pipe. Similar to the spiral pipe section, the protrusions 03 also serve to disturb the natural gas and hydrogen, allowing for secondary and tertiary mixing of the hydrogen and natural gas, thus improving the uniformity of the blending. Moreover, this natural gas-hydrogen blending structure has low manufacturing costs, good adaptability, and facilitates efficient, rapid, and thorough mixing of natural gas and hydrogen, not only improving mixing uniformity but also reducing the risk of leakage in hydrogen-blended natural gas pipelines.

[0046] Example 2

[0047] like Figure 3 As shown, this embodiment is a natural gas hydrogen-blended structure. The difference from embodiment 1 is that the spiral section 02 of the hydrogen injection pipe in this embodiment is parallel to the natural gas main pipeline 01.

[0048] Specifically, the natural gas-hydrogen blending structure includes a natural gas main pipeline 01 and a hydrogen injection pipe connected to each other. The hydrogen injection pipe includes a straight pipe section 05 and a spiral section 02. The spiral section 02 is located inside the natural gas main pipeline 01, and the straight pipe section 05 is located outside the natural gas main pipeline 01. The spiral section 02 of the hydrogen injection pipe is provided with multiple gas outlet holes 04, and a protrusion 03 is provided between two adjacent gas outlet holes 04.

[0049] Specifically, the natural gas main pipeline 01 is provided with a through hole for installing a hydrogen injection pipe. The straight pipe section 05 of the hydrogen injection pipe extends through the through hole to the outside of the natural gas main pipeline 01. A sealing component is installed at the through hole. The sealing component includes an annular groove 07 provided on the hole wall of the through hole. A sealing ring 08 is installed in the annular groove 07. An annular protrusion 06 is provided on the straight pipe section 05 of the hydrogen injection pipe to engage with the annular groove 07.

[0050] Specifically, in order to prevent the hydrogen injection pipe from clogging the natural gas main pipeline 01, the diameter of the hydrogen injection pipe in this embodiment is less than 1 / 2 of the diameter of the natural gas main pipeline 01.

[0051] The method of using the natural gas-hydrogen mixing structure in this embodiment to mix natural gas and hydrogen is the same as in Embodiment 1. Natural gas is introduced into the main natural gas pipeline 01 at a flow rate of 10 m / s, and hydrogen is introduced from the straight section 05 of the hydrogen injection pipe at a flow rate of 10 m / s, and then enters the spiral section in the main natural gas pipeline 01. The hydrogen flows out from the outlet 04 and the tail of the spiral pipe into the main natural gas pipeline 01, and comes into contact with and mixes with the natural gas in the main natural gas pipeline 01.

[0052] Compared to Example 1, this example sets the spiral section 02 of the hydrogen injection pipe parallel to the main natural gas pipeline 01, placing the hydrogen injection pipe at the center of the main natural gas pipeline 01. This allows the outlet 04 on the spiral section 02 of the hydrogen injection pipe to face in all directions, ensuring that natural gas passing through the center of the spiral section 02, as well as natural gas passing above or below it, can fully contact and mix with the hydrogen discharged from the outlet 04. The installation method of the hydrogen injection pipe in this example further improves the uniformity of the mixing of natural gas and hydrogen.

[0053] Example 3

[0054] like Figure 4 and Figure 5 As shown, this embodiment provides a natural gas hydrogen-blended structure. The difference from Embodiment 1 is that, in addition to including all the structural features in Embodiment 1, this embodiment also includes a rotary connector 09 connected to the straight pipe section 05 of the hydrogen injection pipe, and the connection between the straight pipe section 05 of the hydrogen injection pipe and the natural gas main pipeline 01 is a rotary connection.

[0055] Specifically, the rotary connector 09 includes a main connector 10 and a secondary connector 12, and a bearing 11 is provided between the main connector 10 and the secondary connector 12. Both the main connector 10 and the secondary connector 12 are provided with an installation structure for installing pipes. The installation structure includes an external thread 13 provided at the connection end of the main connector 10 and the secondary connector 12.

[0056] Specifically, both the main connector 10 and the auxiliary connector 12 have a groove 14 at one end where the pipe is installed. A spring 15 is installed inside the groove 14. The pipe is installed on the main connector 10 and the auxiliary connector 12 by using a locking block 19 on the pipe that engages with the groove 14 and an internal thread. By installing the spring 15 in the groove 14, when the pipe is threadedly connected to the main connector 10 and the auxiliary connector 12, both ends of the spring 15 are always abutting against the pipe and the rotary connector 09, making the connection between the pipe and the rotary connector 09 taut. This makes the threaded end of the hydrogen injection pipe more stable when rotating, and the threaded connection also makes it less likely for the pipe to detach from the rotating structure.

[0057] Specifically, both the main connector 10 and the auxiliary connector 12 are provided with sealing grooves 16, and sealing blocks 17 are installed on the pipeline to seal them to the main connector 10 and the auxiliary connector 12. By providing a sealing structure at the connection between the main connector 10 and the auxiliary connector 12 and the pipeline, the sealing performance is improved, and hydrogen leakage can be further prevented.

[0058] During installation, the straight sections 05 of the hydrogen injection pipes at both the upper and lower ends of the rotary connector 09 are threaded into place. After the threaded connection is complete, the two ends of the spring 15 remain in contact with the hydrogen injection pipe and the rotary connector, ensuring that the connection between the hydrogen injection pipe and the rotary connector is always taut, thus improving the stability of the hydrogen injection pipe during rotation. Furthermore, the threaded connection between the hydrogen injection pipe and the rotary connector 09 makes installation easier and provides better sealing, preventing leaks during use.

[0059] When mixing natural gas and hydrogen using the natural gas-hydrogen blending structure in this embodiment, natural gas is introduced into the main natural gas pipeline 01 at a flow rate of 10 m / s, while hydrogen is introduced from the straight section 05 of the hydrogen injection pipe at a flow rate of 10 m / s. At this time, the rotary connector 09 rotates using the power generated by the airflow, thereby causing the spiral section 02 of the hydrogen injection pipe to rotate. After the hydrogen in the hydrogen injection pipe is discharged from the outlet 04, the hydrogen and natural gas are mixed more quickly and thoroughly as the spiral section 02 of the hydrogen injection pipe rotates.

[0060] Compared with Examples 1 and 2, this example connects the rotating connector 09, so that after hydrogen is introduced into the hydrogen injection pipe, the spiral section 02 of the hydrogen injection pipe rotates, which plays a role in stirring and disturbing the gas, further accelerating the mixing of natural gas and hydrogen in the natural gas pipeline, shortening the mixing time of natural gas and hydrogen, and improving the mixing efficiency of natural gas and hydrogen.

[0061] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention. It is obvious to those skilled in the art that this application is not limited to the details of the above exemplary embodiments, and that the present application can be implemented in other specific forms without departing from the spirit or basic characteristics of the present application. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this application is defined by the appended claims rather than the foregoing description, and therefore all changes falling within the meaning and scope of the equivalents of the claims are intended to be included within this application.

Claims

1. A natural gas hydrogen-doped hybrid structure, characterized in that, It includes a natural gas main pipeline (01) and a hydrogen injection pipe that are connected to each other. The hydrogen injection pipe includes a straight pipe section (05) and a spiral section (02). The spiral section (02) is located inside the natural gas main pipeline (01), and the straight pipe section (05) is located outside the natural gas main pipeline (01). The spiral section (02) of the hydrogen injection pipe is provided with a plurality of gas outlet holes (04), and a protrusion (03) is provided between two adjacent gas outlet holes (04).

2. The natural gas hydrogen-blended structure according to claim 1, characterized in that, The natural gas main pipeline (01) is provided with a through hole (18) for installing the hydrogen injection pipe. The straight section (05) of the hydrogen injection pipe extends through the through hole (18) to the outside of the natural gas main pipeline (01). A sealing component is installed at the through hole (18).

3. The natural gas hydrogen-blended structure according to claim 2, characterized in that, The sealing assembly includes an annular groove (07) provided on the wall of the through hole (18), a sealing ring (08) installed in the annular groove (07), and an annular protrusion (06) provided on the straight section (05) of the hydrogen injection pipe to engage with the annular groove (07).

4. The natural gas hydrogen-blended structure according to claim 1, characterized in that, A rotary connector (09) is also connected to the straight section (05) of the hydrogen injection pipe, and the straight section (05) of the hydrogen injection pipe is rotatably connected to the natural gas main pipeline (01).

5. A natural gas hydrogen-blended structure according to claim 4, characterized in that, The rotary connector (09) includes a main connector (10) and a secondary connector (12), and a bearing (11) is provided between the main connector (10) and the secondary connector (12). Both the main connector (10) and the secondary connector (12) are provided with an installation structure for installing pipes.

6. A natural gas hydrogen-doped hybrid structure according to claim 5, characterized in that, The mounting structure includes external threads (13) at the connection ends of the main connector (10) and the auxiliary connector (12).

7. A natural gas hydrogen-doped hybrid structure according to claim 5, characterized in that, Both the main connector (10) and the auxiliary connector (12) have a slot (14) at one end where the pipe is installed. A spring (15) is installed in the slot (14). The pipe is installed on the main connector (10) and the auxiliary connector (12) by setting a locking block (19) on the pipe that engages with the slot (14) and an internal thread.

8. A natural gas hydrogen-doped hybrid structure according to claim 7, characterized in that, Both the main connector (10) and the auxiliary connector (12) are provided with sealing grooves (16), and sealing blocks (17) are provided on the pipeline to seal them to the main connector (10) and the auxiliary connector (12).

9. A natural gas hydrogen-blended structure according to claim 1, characterized in that, The diameter of the hydrogen injection pipe is less than 1 / 2 of the diameter of the natural gas main pipeline (01).

10. A method for blending natural gas with hydrogen, characterized in that, The hydrogen mixing structure described in any one of claims 1 to 9 is used, specifically: natural gas is introduced into the main natural gas pipeline (01), and hydrogen is introduced into the hydrogen injection pipe. The natural gas and hydrogen are introduced at the same flow rate. The hydrogen entering the spiral section (02) of the hydrogen injection pipe is discharged from the outlet (04) and fully mixes with the natural gas in the main natural gas pipeline (01).

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