CN111748140A

CN111748140A - CNTs (carbon nanotubes) conduction technology-based combustible gas composite pipe and preparation method thereof

Info

Publication number: CN111748140A
Application number: CN202010668680.XA
Authority: CN
Inventors: 倪奉尧; 陈成; 孔智勇; 孔德彬; 顾浩; 伍金奎; 孔涛
Original assignee: Shandong Donghong Pipe Industry Co Ltd
Current assignee: Shandong Donghong Pipe Industry Co Ltd
Priority date: 2020-07-13
Filing date: 2020-07-13
Publication date: 2020-10-09
Anticipated expiration: 2040-07-13
Also published as: CN111748140B

Abstract

The utility model provides a compound pipe of combustible gas and preparation method based on CNTs conductive technology relates to the tubular product field of preparing, includes the three-layer that arranges from inside to outside in proper order, and first layer and third layer all adopt CNTs mixture to make, and CNTs mixture includes the raw materials of following parts by weight: 100 parts of high-density polyethylene, 0.3-3 parts of CNTs, 0.5-5 parts of CNTs active dispersant, 0.2-1 part of antioxidant and 1-4 parts of conductive carbon black; the CNTs are pretreated to form colloidal slurry, and then the colloidal slurry is dispersed and freeze-dried, so that the CNTs are effectively dispersed, and the requirements of raw materials in the preparation process of the pipe are met.

Description

CNTs (carbon nanotubes) conduction technology-based combustible gas composite pipe and preparation method thereof

Technical Field

The disclosure relates to the field of pipe preparation, in particular to a CNTs (carbon nanotubes) conduction technology-based combustible gas composite pipe and a preparation method thereof.

Background

The statements in this section merely provide background information related to the present disclosure and may not necessarily constitute prior art.

At present, a large amount of PE pipelines are used in domestic combustible gas conveying pipelines. In the conveying process of combustible gas, intermolecular friction between the gas and the pipeline and between the gas and the inner wall of the pipeline can generate electric charges, the PE pipe is insulated from the ground, the formed electric charges cannot be released, and the accumulation of the electric charges can form static electricity. Because the combustible gas belongs to flammable and explosive gas, the generation of static can bring huge potential safety hazard to the transportation and the use of the combustible gas. At present, the main method for solving the problem of static electricity generation in China is to control the flow rate of combustible gas to reduce the generation of electric charge; the flow rate is reduced in a manner that does not satisfy the demand for rapid delivery of combustible gas.

The conductive performance of the pipe is generally increased by adding conductive carbon black into the PE raw material, and the conductive carbon black forms a net structure in the polyethylene to exert the conductive performance, and the conductive performance needs to be added by 20-30 percent to meet the requirement; in addition, CNTs conduction technology can also be used, and in the case of dispersion using CNTs, ball mill dispersion, solvent dispersion, ultrasonic dispersion, dispersant dispersion, and the like are often used.

The inventor finds that the conductive carbon black is of a spheroidal structure, and the tensile strength, the elongation, the impact resistance and the long-term hydrostatic pressure performance of PE can be influenced when the conductive carbon black is added into the PE in a large amount, so that the loss is brought to the physical performance of the pipe, and the pipe bursting phenomenon is frequently caused when the conductive carbon black is applied to the pipe for a long time, and the risk is high; because the conductive carbon black is not continuously distributed in the pipe, the static electricity on the inner wall of the pipe cannot completely flow to the anti-static grounding device; in addition, the CNTs aggregate is crushed and extruded tightly during the ball milling process, and is difficult to disperse, and a large amount of organic solvent remains when solvent dispersion is adopted, so that the CNTs conductive technology is difficult to effectively and reasonably apply due to the dispersion problem of the CNTs.

Disclosure of Invention

The purpose of the disclosure is to provide a CNTs conductive technology-based combustible gas composite tube and a preparation method thereof, aiming at the defects in the prior art, the CNTs are pretreated to form colloidal slurry, then the colloidal slurry is dispersed and freeze-dried, the CNTs are effectively dispersed, and the requirements of raw materials in the preparation process of the tube are met.

The first purpose of the present disclosure is to provide a CNTs conduction technology-based combustible gas composite tube, which adopts the following technical scheme:

the composite material comprises three layers which are sequentially arranged from inside to outside, wherein the first layer and the third layer are both made of CNTs mixed materials, and the CNTs mixed materials comprise the following raw materials in parts by weight: 100 parts of high-density polyethylene, 0.3-3 parts of CNTs, 0.5-5 parts of CNTs active dispersant, 0.2-1 part of antioxidant and 1-4 parts of conductive carbon black.

The second purpose of the present disclosure is to provide a method for preparing CNTs mixture, which adopts the following technical scheme:

the method comprises the following steps:

dissolving CNTs in a CNTs active dispersion liquid to form a completely-soaked suspension, stirring the suspension, and heating to form colloidal slurry;

grinding and dispersing the colloid slurry, drying to obtain dispersed CNTs, and mixing with high-density polyethylene;

and carrying out melt blending, extrusion granulation on the mixture, the antioxidant and the conductive carbon black to obtain a blended material.

The third purpose of the present disclosure is to provide a method for preparing a flammable gas composite pipe based on a CNTs conductive technology, which adopts the following technical scheme:

the method comprises the following steps:

the method comprises the following steps of (1) taking CNTs mixed material as a first layer and a third layer, taking polyethylene as a second layer, and carrying out extrusion forming by adopting a three-layer co-extrusion mode to obtain a pipe;

carrying out cooling forming on the extruded and formed pipe through vacuum cooling spraying, and then carrying out fixed-length cutting;

the end of the pipe is matched with the sealing ring to seal, and the inner wall and the outer wall of the electric connection pipe form a closed conductive whole.

Compared with the prior art, the utility model has the advantages and positive effects that:

(1) dissolving CNTs in a CNTs active dispersion liquid to form a completely-soaked suspension, heating the suspension in a stirring state to form slurry, dispersing the colloidal slurry through a colloid grinder, then putting the dispersed colloidal slurry into a vacuum freeze dryer to obtain the dispersed CNTs, wherein the dispersing agent and the double dispersing capability of the grinder enable the dispersing effect of the CNTs to reach the ideal use requirement;

(2) the slurry is powdered again through a vacuum freeze dryer, and the CNTs are prevented from agglomerating again due to the treatment of the dispersing agent and the grinding machine on the surfaces of the CNTs;

(3) the cost of the raw materials of the pipe can be effectively reduced through three-layer co-extrusion of the pipe and welding of the conductive sealing ring, and the special material for the combustible gas in the middle layer can ensure that the pipe keeps the original mechanical property and meets the strength requirement;

(4) the sealing ring is matched with the inner layer and the outer layer of the composite pipe, the same CNTs mixed materials are adopted for the inner layer and the outer layer of the composite pipe, the composite pipe has corresponding conductivity, a closed conductive interface is formed, the conductivity is greatly improved, electric charges generated by friction between gas and between gas and the inner wall of the pipeline are introduced into the outer wall of the pipeline, the outer wall is grounded, the electric charges are released, and safe conveying of the electric charges in the pipeline is guaranteed.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

Fig. 1 is a schematic structural diagram of a composite pipe in embodiments 1, 2, and 3 of the present disclosure;

fig. 2 is a schematic cross-sectional structure diagram of a composite pipe in embodiments 1, 2, and 3 of the present disclosure.

Detailed Description

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an", and/or "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof;

for convenience of description, the words "up", "down", "left" and "right" in this disclosure, if any, merely indicate that the directions of movement are consistent with those of the figures themselves, and are not limiting in structure, but merely facilitate the description of the invention and simplify the description, rather than indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present disclosure.

As described in the background art, in the prior art, when a gas delivery pipeline with conductive performance is prepared, a large amount of conductive carbon black is added into the pipeline, but the addition of a large amount of PE affects the tensile strength, elongation, impact resistance and long-term hydrostatic performance of PE, thereby causing loss of physical properties of the pipe, and the pipe bursting phenomenon often occurs for long-term application of the pipe. In order to solve the problems, the disclosure provides a CNTs conductive technology-based combustible gas composite tube and a preparation method thereof.

Interpretation of terms:

CNTs are carbon nanotubes; CNTs are coaxial circular tube one-dimensional nano materials with several layers to tens of layers formed by hexagonally arranged carbon atoms. P electrons of carbon atoms on the carbon nano tube form a large-range delocalized pi bond, and the carbon nano tube has excellent conductivity due to the obvious conjugation effect;

however, due to the inertia of the surface of the carbon nanotube and the high aspect ratio structure, the dispersion of the carbon nanotube is very difficult, and the effect of the carbon nanotube used for conductive fillers is not good;

mixing materials: PE, CNTs and additives are mixed and granulated according to a certain formula proportion to obtain the composite material.

Example 1

In an exemplary embodiment of the present disclosure, as shown in fig. 1 to 2, a CNTs conductive technology based combustible gas composite tube is provided.

The composite tube is prepared by mixing ingredients and polyethylene materials, and the ingredients are prepared by adding and matching CNTs active dispersant, antioxidant, conductive carbon black and high-density polyethylene matrix;

the formula is as follows: 100 parts of high-density polyethylene matrix, 0.3-3 parts of CNTs, 0.5-5 parts of CNTs active dispersant, 0.2-1 part of antioxidant and 1-4 parts of conductive carbon black. Wherein the dispersant is dissolved in water at a ratio of 1:50-1:100 to prepare a dispersion liquid for use.

The CNTs can be one or more of single-wall nanotubes, double-wall nanotubes and multi-wall nanotubes, and industrial-grade multi-wall nanotubes can be preferably selected for the convenience of industrial production; the tube diameter is 10-20 nm and the length is 20-100 μm.

The high density polyethylene may be one or more of grade 80, grade 100, grade 112;

the CNTs active dispersant can be one or more of alcohol dispersant and ester dispersant;

the conductive carbon black may be one or more of superconducting carbon black, acetylene black, and conventional conductive carbon black.

Example 2

In another exemplary embodiment of the present disclosure, a method for preparing a CNTs blend is provided, as shown in fig. 1-2.

The method comprises the following steps:

In this example, the preparation method is described in detail as follows:

1. dissolving CNTs in a CNTs active dispersion liquid to form a completely-soaked suspension, and heating the suspension in a 60-120 ℃ environment for 2-6 hours under a stirring state to form slurry. Dispersing the colloidal slurry through a colloidal grinder, and then putting the dispersed colloidal slurry into a vacuum freeze dryer to obtain dispersed CNTs; wherein the colloid mill is selected from GSMD2000 model of Shanghai Si Jun machine.

2. Mixing the dispersed CNTs and the high-density polyethylene matrix through a high-speed mixer at the rotation speed of 200-800r/min, the mixing temperature of 80-120 ℃ and the mixing time of 20-60 min.

3. And (3) carrying out melt blending, extrusion and granulation on the mixture antioxidant and the conductive carbon black by using a double-screw extruder. The extrusion temperature is 160-300 ℃, the rotation speed of the extruder is 250-1000r/min, and the mixed material is obtained.

The dispersing effect of the CNTs can reach the ideal use requirement by adopting the double dispersing capability of a dispersing agent and a colloid grinder;

the slurry is powdered again through a vacuum freeze dryer, and the CNTs are prevented from agglomerating again due to the treatment of the dispersing agent and the grinding machine on the surfaces of the CNTs.

Example 3

In another exemplary embodiment of the present disclosure, as shown in fig. 1 to fig. 2, a method for preparing a combustible gas composite tube based on a CNTs conductive technology is provided.

The method comprises the following steps:

In this example, the preparation method thereof is described in detail with reference to the accompanying drawings;

drying the raw materials: the raw materials with the performance meeting the requirements are dried by adopting drying and heating equipment before processing, the drying temperature is set to be 75-90 ℃, and the drying time is more than or equal to 3 h.

Extruding by an extruder: extruding the raw materials obtained in the step 1 through an extruder, wherein the extruder comprises a main machine part, a screw, a machine barrel, a machine head and a heating sheet.

The temperature of the heating sheet is set according to the model of the pipe;

the extruder comprises three sets of main machine parts, a screw, a machine barrel and heating sheets, and an extruder head is shared.

The extrusion mode adopts a three-layer co-extrusion production scheme to produce the pipe, the inner layer of the pipe is made of CNTs mixed material, the middle layer of the pipe is made of conventional fuel gas pipe polyethylene material, and the outer layer of the pipe is made of CNTs mixed material. The special material for the combustible gas can ensure the original mechanical property of the pipe;

the three-layer co-extrusion is that the inner, middle and outer three layers of the pipe are extruded by different screw extruders at the same time, and are extruded and molded by respective mouth dies at the head of the same extruder;

the tubing can be of size d_n20-d_n630；

The wall thickness of the three-layer co-extrusion inner layer and the three-layer co-extrusion outer layer is 0.5-5 mm;

the wall thickness of the three-layer co-extrusion middle layer is 2-50 mm.

Vacuum spray forming: and (3) cooling and forming the material obtained in the step (2) by using a vacuum cooling spray box, wherein the vacuum cooling spray box comprises a sizing sleeve and a vacuum spray system.

Traction cutting: the pipe which is completely cooled and formed is drawn by a tractor, and is cut to a fixed length through a cutting machine according to the requirement.

The sealing ring matched with the composite pipe produced by the CNTs mixed material can be produced by adopting a mode of injection molding or turning after pipe extrusion.

The matched sealing ring is used for sealing the composite pipe, and the sealing ring and the inner and outer walls of the pipe are produced by the same material, so that the inner and outer walls of the pipe form a sealed conductive whole.

Of course, it can be understood that the pipe is prepared by a three-layer co-extrusion technology, and the conductive function can be realized by the wall thickness of the inner layer and the outer layer being 0.5-1.0 mm; the preparation of the pipe can realize the conductive function by adopting the single-layer extrusion of the complete CNTs material.

Sealing rings are matched at two ends of the pipe, one side of each sealing ring is attached to the inner wall of the pipe, and the other side of each sealing ring is attached to the outer wall of the pipe and attached to the end face of the pipe;

the sealing ring is made of conductive materials and is electrically connected with the inner wall formed by the first layer and the outer wall formed by the third layer in the pipe.

The basic properties of the composite pipe prepared are as follows:

the sealing ring is matched with the inner layer and the outer layer of the composite pipe, the same CNTs mixed materials are adopted for the inner layer and the outer layer of the composite pipe, the composite pipe has corresponding conductivity, a closed conductive interface is formed, the conductivity is greatly improved, electric charges generated by friction between gas and between gas and the inner wall of the pipeline are introduced into the outer wall of the pipeline, the outer wall is grounded, the electric charges are released, and safe conveying of the electric charges in the pipeline is guaranteed.

Example 4

In another embodiment of the present disclosure, a method for preparing a composite pipe as a whole using embodiments 1, 2, and 3 is provided, and three sets of comparative examples are given, specifically as follows:

a composite pipe preparation method comprises the following steps:

1. a production and preparation method of a combustible gas composite pipe based on a CNTs conductive technology comprises the following mixed ingredients in parts by mass: 100 parts of high-density polyethylene matrix, 3 parts of CNTs, 5 parts of CNTs active dispersant, 0.5 part of antioxidant and 4 parts of conductive carbon black. Wherein the dispersant is dissolved in water in a ratio of 1:100 to prepare a dispersion liquid for use.

2. Dissolving CNTs in a CNTs active dispersion liquid to form a completely-soaked suspension, and heating the suspension in a 100 ℃ environment for 4 hours under a stirring state to form slurry. Dispersing the colloidal slurry by a colloid mill (GSMD2000, Shanghai Si Jun machine), and then putting the dispersed colloidal slurry into a vacuum freeze dryer to obtain the dispersed CNTs.

3. And mixing the dispersed CNTs and the high-density polyethylene matrix through a high-speed mixer at the rotating speed of 500r/min, the mixing temperature of 80 ℃ and the mixing time of 60 min.

4. And (2) carrying out melt blending, extrusion and granulation on the mixture of the polyethylene and the CNTs, the antioxidant and the conductive carbon black by using a double-screw extruder. The extrusion temperature is 170-200 ℃, the rotation speed of the extruder is 350r/min, and the mixed material is obtained.

5. And (4) preparing the mixed material prepared in the step (4) into a pipe.

(1) Extruding by an extruder: extruding the raw material obtained in the step 1 by an extruder,

the extruder comprises a main machine part, a screw, a machine barrel, a machine head and a heating sheet.

The temperature of the heating sheet is set according to the model of the pipe;

the three-layer co-extrusion is that the inner, middle and outer three layers of the pipe are extruded by different screw extruders at the same time, and are extruded and molded by respective mouth dies at the head of the same extruder; the pipe specification is 110 × 10.0. The wall thickness of the inner layer and the outer layer is 1.0mm, and the wall thickness of the middle layer is 8.0 mm.

(2) Vacuum spray forming: and (3) cooling and forming the material obtained in the step (2) by using a vacuum cooling spray box, wherein the vacuum cooling spray box comprises a sizing sleeve and a vacuum spray system.

(3) Traction cutting: the pipe which is completely cooled and formed is drawn by a tractor, and is cut to a fixed length through a cutting machine according to the requirement.

(4) The sealing ring matched with the composite pipe is produced by using the CNTs mixed material in an injection molding production mode.

(5) And sealing the composite pipe by the matched sealing ring.

The properties of the mixture and the internal and external surface resistances of the pipes are shown in Table 1

Comparative example 1

The production method of the combustible gas composite pipe comprises the following mixed materials in parts by mass: 100 parts of high-density polyethylene matrix, 0.5 part of antioxidant and 4 parts of conductive carbon black.

And secondly, melting, blending, extruding and granulating the polyethylene, the antioxidant and the conductive carbon black by using a double-screw extruder. The extrusion temperature is 170-200 ℃, the rotation speed of the extruder is 350r/min, and the mixed material is obtained.

Thirdly, the mixed ingredients prepared in the second step are used for preparing the pipe.

Drying raw materials: the raw materials with the performance meeting the requirements are dried by adopting drying and heating equipment before processing, the drying temperature is set to be 75-90 ℃, and the drying time is more than or equal to 3 h.

Secondly, extruding by an extruder: extruding the raw material obtained in the step 1 by an extruder,

The temperature of the heating sheet is set according to the model of the pipe;

The extrusion mode adopts a three-layer co-extrusion production scheme to produce the pipe, the inner layer of the pipe uses mixed materials, the middle layer uses conventional fuel gas pipe polyethylene materials, and the outer layer uses mixed materials. The special material for the combustible gas can ensure the original mechanical property of the pipe;

Performing vacuum spray molding: and (3) cooling and forming the material obtained in the step (2) by using a vacuum cooling spray box, wherein the vacuum cooling spray box comprises a sizing sleeve and a vacuum spray system.

Traction and cutting: the pipe which is completely cooled and formed is drawn by a tractor, and is cut to a fixed length through a cutting machine according to the requirement.

And fifthly, producing the sealing ring matched with the composite pipe by using the mixed material in an injection molding production mode.

Sixthly, sealing the composite pipe by using a matched sealing ring.

Comparative example 2

The production and preparation method of the combustible gas composite pipe based on the CNTs conductive technology comprises the following mixed ingredients in parts by mass: 100 parts of high-density polyethylene matrix, 3 parts of CNTs, 5 parts of CNTs active dispersant, 0.5 part of antioxidant and 4 parts of conductive carbon black.

Mixing CNTs and a high-density polyethylene matrix through a high-speed mixer at the rotating speed of 500r/min, the mixing temperature of 80 ℃ and the mixing time of 60 min.

Thirdly, the mixture of the polyethylene and the CNTs, the antioxidant and the conductive carbon black are melted and blended by a double-screw extruder, and are extruded and granulated. The extrusion temperature is 170-200 ℃, the rotation speed of the extruder is 350r/min, and the mixed material is obtained.

Fourthly, the mixed ingredients prepared in the third step are used for preparing the pipe.

The temperature of the heating sheet is set according to the model of the pipe;

And fifthly, producing the sealing ring matched with the composite pipe by using the CNTs mixed material in an injection molding production mode.

Sixthly, sealing the composite pipe by using a matched sealing ring.

The mixing and compounding properties and the internal and external surface resistances of the pipes are shown in Table 1.

Comparative example 3

The production and preparation method of the combustible gas composite pipe based on the CNTs conductive technology comprises the following mixed ingredients in parts by mass: 100 parts of high-density polyethylene matrix, 3 parts of CNTs, 5 parts of CNTs active dispersant, 0.5 part of antioxidant and 4 parts of conductive carbon black. Wherein the dispersant is dissolved in water in a ratio of 1:100 to prepare a dispersion liquid for use.

Dissolving the CNTs in the CNTs active dispersion liquid to form a completely soaked suspension, and heating the suspension in a 100 ℃ environment for 4 hours under a stirring state to form slurry. Dispersing the colloidal slurry by a colloid mill (GSMD2000, Shanghai Si Jun machine), and then putting the dispersed colloidal slurry into a vacuum freeze dryer to obtain the dispersed CNTs.

Thirdly, mixing the dispersed CNTs and the high-density polyethylene matrix through a high-speed mixer at the rotating speed of 500r/min and the mixing temperature of 80 ℃ for 60 min.

And fourthly, the mixture of the polyethylene and the CNTs, the antioxidant and the conductive carbon black are melted and blended by a double-screw extruder, and are extruded and granulated. The extrusion temperature is 170-200 ℃, the rotation speed of the extruder is 350r/min, and the mixed material is obtained.

Fifthly, preparing the pipe by using the mixed material prepared by the fourth step.

The temperature of the heating sheet is set according to the model of the pipe;

Traction and cutting: the pipe which is completely cooled and formed is drawn by a tractor, and is cut to a fixed length through a cutting machine according to the requirement

And fifthly, the sealing ring matched with the composite pipe produced by using the conventional gas pipe polyethylene material is adopted in the injection molding production mode.

Sixthly, sealing the composite pipe by using a matched sealing ring.

TABLE 1

The data comparison in table 1 shows that the electrical conductivity of the pipe can be effectively improved by adding the CNTs. The vacuum freeze drying technology can improve the dispersion of the CNTs, and meanwhile, the effective dispersion of the CNTs can also be obtained and is a key factor influencing the electrical conductivity. As can be seen from comparative example 3, only when CNTs are formed as a continuous whole, excellent conductivity can be exhibited.

According to the practical production case, the ton price of the special material for the gas pipeline is about 9000 yuan, the ton price of the CNTs mixed material is about 15000 yuan, and the cost can be saved by 30-40% by adopting a three-layer co-extrusion production mode compared with the cost of the single antistatic CNTs mixed material.

The above description is only a preferred embodiment of the present disclosure and is not intended to limit the present disclosure, and various modifications and changes may be made to the present disclosure by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. The utility model provides a compound pipe of combustible gas based on CNTs conductive technology which characterized in that, includes the three-layer that arranges in proper order from inside to outside, and first layer and third layer all adopt CNTs to mix the batching and make, and CNTs mixes the batching and includes the raw materials of following parts by weight: 100 parts of high-density polyethylene, 0.3-3 parts of CNTs, 0.5-5 parts of CNTs active dispersant, 0.2-1 part of antioxidant and 1-4 parts of conductive carbon black.

2. The CNTs conduction technology-based combustible gas composite tube of claim 1, wherein the CNTs are selected from at least one of single-walled carbon nanotubes, double-walled carbon nanotubes and multi-walled carbon nanotubes.

3. The CNTs conductive technology-based combustible gas composite tube of claim 1, wherein the CNTs active dispersant is alcohol dispersant and/or ester dispersant; the high-density polyethylene is at least one of 80-grade, 100-grade and 120-grade, and the conductive carbon black is at least one of superconducting carbon black, acetylene carbon black and conventional conductive carbon black.

4. A preparation method of a CNTs mixed material is characterized by comprising the following steps:

5. The method of preparing a compound according to claim 4, wherein the colloidal slurry is dried by vacuum freezing after being milled and dispersed.

6. The method of claim 4, wherein the CNTs active dispersion is prepared by dissolving CNTs active dispersant in water.

7. A method for preparing a CNTs conduction technology-based combustible gas composite tube according to any one of claims 1 to 3, comprising the following steps:

8. The method of claim 7, wherein the blend and polyethylene are dried before extrusion, wherein the polyethylene is a gas pipe polyethylene.

9. The method according to claim 7, wherein the sealing rings are fitted to both ends of the tube, and one side of each sealing ring is fitted to the inner wall of the tube, and the other side of each sealing ring is fitted to the outer wall of the tube and is fitted to the end face of the tube.

10. The method of claim 9, wherein the sealing ring is made of an electrically conductive material and electrically connects the inner wall of the first layer and the outer wall of the third layer of the tube.