In-service pipeline spraying process and spraying device

Abstract

The invention belongs to the technical field of natural gas pipelines, and discloses an in-service pipeline spraying process and a spraying device.The spraying device comprises a spraying head, a liquid storage tank and a hydraulic pump. The in-service pipeline spraying process comprises the following steps that an appropriate agent is selected according to a pipeline to be sprayed, the theoretical thickness of a needed agent adsorption film is determined, and the theoretical thickness of the needed agent adsorption film is determined; calculating the theoretical medicament dosage so as to determine the size and the number of the liquid storage tanks; the spraying device is arranged in the pipeline and moves along with the airflow of the conveyed gas, and the hydraulic pump sprays the medicament in the liquid storage tank in the direction opposite to the airflow direction of the conveyed gas through the sprayer and sprays the medicament on the inner wall of the pipeline. By means of the in-service pipeline spraying process, the natural gas drag reducer spraying distance is long, and the film forming thickness is uniform.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas pipelines, and particularly relates to a spraying process and a spraying device for in-service pipelines. Background Art

[0002] As a clean energy source, natural gas occupies an important position in the global energy structure. The long-distance pipeline transportation efficiency of natural gas directly affects the economy and reliability of energy supply. During the operation of natural gas pipelines, natural gas drag reducers adsorb on the inner wall of the pipeline through their polar ends, forming a smooth elastic film on the inner surface of the pipeline. On the one hand, it reduces the absolute roughness of the pipe wall, and on the other hand, it reduces the energy loss of the disordered flow of gas molecules at the pipe wall interface, effectively reducing the fluid friction resistance. It can enable the natural gas pipeline to achieve a drag reduction rate of 5% - 15%, which is an important technical means to increase the throughput of natural gas pipelines.

[0003] However, the distance between compressor stations of natural gas pipelines is usually 100 - 250 km. The existing injection process of natural gas drag reducers usually adopts the atomized injection method at a fixed point at the outlet end. On the one hand, restricted by the diffusion attenuation characteristics of drag reducer molecules in the turbulent flow field, the concentration of drag reducers decays exponentially. The film thickness formed on the pipe wall is uneven and gradually thins. The effective action distance is generally about 50 km, and the actual atomized coverage area of the pipe wall is less than 50% of the inner surface of the pipe wall, unable to achieve uniform film formation covering the entire pipe wall section, resulting in low drag reduction efficiency and limited drag reduction and throughput increase effects. On the other hand, the single-point injection at the outlet end is affected by structures such as elbows and valves, and the effective spraying distance of the drag reducer may be further shortened. The above problems seriously restrict the engineering application of natural gas drag reducer technology. Summary of the Invention

[0004] The purpose of the present invention is to provide a spraying process and a spraying device for in-service pipelines to solve the problems of short effective action distance and uneven film thickness in the spraying of natural gas drag reducers.

[0005] To achieve this purpose, the present invention adopts the following technical solutions:

[0006] A spraying process for in-service pipelines, which uses a spraying device to spray a medicament onto the inner wall of the pipeline. The spraying device includes a spray head, a liquid storage tank, and a hydraulic pump. The spraying process for in-service pipelines includes the following steps:

[0007] Select a suitable medicament according to the pipeline to be sprayed, determine the theoretical thickness required for the medicament to adsorb and form a film, calculate the theoretical medicament dosage, and thereby determine the size and number of the liquid storage tanks;

[0008] Place the spraying device in the pipeline and make it travel along with the conveying gas flow. The hydraulic pump sprays the medicament in the liquid storage tank through the spray head in the direction opposite to the conveying gas flow direction and sprays it onto the inner wall of the pipeline.

[0009] Optionally, the amount of chemical agent filled in the spraying device at one time is equal to the amount of chemical agent required for the pipe section between adjacent gas compressor stations of the pipeline, and the spraying device replenishes the chemical agent at the pig launcher of the pipeline.

[0010] Optionally, the calculation formula for the theoretical dosage of the chemical agent is:

[0011] V = π×d×L 1 ×δ×ξ

[0012] In the formula, d is the inner diameter value of the pipe section, L 1 is the distance of the pipe section; δ is the film thickness of the chemical agent, and ξ is the injection coefficient.

[0013] The spraying device is used for the above-mentioned in-service pipeline spraying process. The spraying device includes a hydraulic pump, a spray head and a liquid storage tank. The hydraulic pump is connected to the liquid storage tank, and the spray head is located outside the liquid storage tank and connected to the hydraulic pump.

[0014] Optionally, the liquid storage tank is set to be cylindrical, and the outer diameter of the liquid storage tank is between 90% and 99% of the inner diameter of the pipeline.

[0015] Optionally, one or more liquid storage tanks are provided, and adjacent liquid storage tanks are connected by a flexible anti-pressure hose.

[0016] Optionally, a liquid level sensor is arranged in the liquid storage tank.

[0017] Optionally, the spraying device further includes a positioning module, and the positioning module is configured to determine the position of the spraying device in the pipeline.

[0018] Optionally, the spraying device further includes a guide member, and the guide member is arranged between the spray head and the liquid storage tank for guiding the chemical agent to the inner wall of the pipeline.

[0019] Optionally, the length of the liquid storage tank is 0.5 - 3 m.

[0020] Advantages of the present invention:

[0021] The in-service pipeline spraying process proposed in the present invention uses a spraying device that can move in the pipeline by means of the driving force of the conveying gas to spray the inner wall of the pipeline, which can increase the effective spraying distance of the chemical agent from the migration distance of single-point injection at the outbound end to all pipe sections of the in-service pipeline, realizing uniform adsorption and film formation of the chemical agent on the inner wall surface of the entire pipeline, and significantly improving the spraying effect of the chemical agent. Moreover, the spraying device is atomized by the conveying gas, simplifying the structure of the entire spraying device, reducing the mass of the spraying device, and helping to realize the movement of the spraying device in the pipeline. Description of the Drawings

[0022] Figure 1 is a schematic structural diagram of the spraying device in an embodiment of the present invention;

[0023] Figure 2 is a schematic structural diagram of an in-service pipeline in an embodiment of the present invention;

[0024] Figure 3 is an exploded structural diagram of the guiding member in an embodiment of the present invention.

[0025] In the figure:

[0026] 1. Sprayer; 2. Hydraulic pump; 3. Liquid storage tank; 4. Battery; 5. Positioning module; 6. Protection shell; 7. Liquid level sensor; 8. Pig receiver; 9. Pig launcher; 10. Compressor station A; 11. Compressor station B; 12. Compressor station C. Detailed implementation manners

[0027] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. Additionally, it should be noted that for the sake of description, only parts related to the present invention rather than all structures are shown in the drawings.

[0028] In the description of the present invention, unless otherwise clearly defined and limited, the terms "connected", "connected to", and "fixed" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal connection or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0029] In the present invention, unless otherwise clearly defined and limited, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through other features therebetween. Moreover, the first feature being "above", "above and over", and "on the top of" the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being "below", "below and under", and "under the bottom of" the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is lower than that of the second feature.

[0030] In the description of this embodiment, the orientation or positional relationships such as "upper", "lower", "left", "right", etc. are based on the orientation or positional relationships shown in the drawings. These are only for the convenience of description and simplifying the operations, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention. In addition, the terms "first" and "second" are only used for differentiation in description and have no special meaning.

[0031] Referring Figures 1 - 3 As shown, in an embodiment of the present invention, a spraying process and spraying device for in-service pipelines are proposed, which are used to spray agents including but not limited to drag reducers on the inner wall of the pipeline. The pipeline is mainly used to transport gases such as natural gas. The spraying device can travel along with the gas transported in the pipeline, that is, the gas transported in the pipeline provides power for the movement of the spraying device, without the need to additionally set up a power structure. The spraying device includes a liquid storage tank 3, a spray head 11, and a hydraulic pump 2. The hydraulic pump 2 is connected to the liquid storage tank 3 and is used to provide power for the liquid agent in the liquid storage tank 3, so that the liquid agent sprays out from the spray head 1 connected to the hydraulic pump 2 at a certain flow rate. The spray head 1 is located outside the liquid storage tank 3, and the flow rate of the agent sprayed out by the spray head 1 matches the flow rate of the transported gas to ensure that an agent with a theoretical thickness can be sprayed on the inner wall of the pipeline. Among them, the number of spray heads 1 can be single or multiple. When one spray head 1 is set, it can be used in cooperation with a rotary drive member to achieve 360° dynamic rotation. When multiple spray heads 1 are set, they can be either dynamic or static to spray the agent circumferentially 360° on the inner wall of the pipeline; the number of liquid storage tanks 3 can be 1, or 2 or more. Adjacent liquid storage tanks 3 are connected by flexible pressure-resistant hoses to adapt to the angle change of the pipeline. It should be emphasized that based on the setting that existing pipelines are usually circular pipelines, the liquid storage tank 3 is set in a cylindrical shape, and its outer diameter is slightly smaller than the inner diameter of the pipeline to ensure that the liquid storage tank 3 can travel smoothly in the pipeline (such as passing through elbows). In order to prevent the liquid storage tank 3 from flipping in the pipeline, the outer diameter of the liquid storage tank 3 cannot be too small. Therefore, the outer diameter of the liquid storage tank 3 is usually set between 90% and 99% of the inner diameter of the pipeline, and the length of a single liquid storage tank 3 is generally 0.5 - 3 m. The hydraulic pump 2 can be a diaphragm pump or other types of hydraulic pumps that can meet the functional and parameter requirements. Taking the pipeline transporting natural gas as an example, the working pressure of the hydraulic pump 2 is not higher than 1.1 MPa on the premise of being higher than 0 MPa, it can withstand an environmental pressure of 6 - 12 MPa, an environmental temperature of -20°C - 70°C, and the flow rate is usually 30 - 400 L / h; in addition, a battery 4 for providing a power source for the hydraulic pump 2 is also provided in the spraying device. The battery 4 can withstand an environmental pressure of 6 - 12 MPa and an environmental temperature of -20°C - 70°C.

[0032] Taking the spraying of natural gas drag reducer as an example, the spraying process of an in-service pipeline using the above-mentioned spraying device to spray the pipeline is described in detail below. The in-service pipeline spraying process mainly includes the following steps:

[0033] S1. First, select a suitable natural gas drag reducer according to the pipeline to be sprayed, determine the theoretical thickness of the natural gas drag reducer adsorption film, and calculate the theoretical dosage of the agent, so as to determine the size and number of the liquid storage tanks 3.

[0034] S2. Place the spraying device in the pipeline and make it flow with the conveying gas. The hydraulic pump 2 sprays the natural gas drag reducer in the liquid storage tank 3 through the nozzle 1 in the direction opposite to the conveying gas flow. The sprayed agent is atomized under the action of natural gas and evenly sprayed on the inner wall of the pipeline.

[0035] S3, spraying is completed.

[0036] The above-mentioned in-service pipeline spraying process uses a spraying device that can move in the pipeline with the help of the driving force of the conveying gas to spray the inner wall of the pipeline. It can increase the effective spraying distance of the agent from the migration distance of the single-point injection at the exit end to the entire pipe section of the in-service pipeline, and realize the uniform adsorption and film formation of the agent on the inner wall of the entire pipeline, which significantly improves the spraying effect of the agent. Moreover, the spraying device uses the conveying gas atomization to simplify the structure of the entire spraying device, reduce the mass of the spraying device, and help to realize the movement of the spraying device in the pipeline.

[0037] When the spraying device is located in the pipeline, since the airflow direction of the conveying gas is opposite to the direction in which the medicine is sprayed from the nozzle 1, there is a risk that the medicine is sprayed onto the liquid storage tank 3, which affects the utilization rate of the medicine. Based on this, a connecting pipe is provided between the nozzle 1 and the liquid storage tank 3 so that the nozzle 1 and the liquid storage tank 3 are separated by a certain distance; or a guide is provided between the nozzle 1 and the liquid storage tank 3 to guide the medicine sprayed from the nozzle 1 to the inner wall of the pipeline, and the guide adopts a fan, including blades, a front mesh cover and a rear mesh cover, and the blades are located in the installation space formed by the front mesh cover and the rear mesh cover. The fan is powered by a battery 4 to convert electrical energy into mechanical energy, and the conveying gas is blown to the same direction of the medicine spray through the blades to guide the atomized medicine sprayed from the nozzle 1 to the inner wall of the pipeline. It is particularly noted that the outer periphery of the front mesh cover is hollowed out, while the center is solid, and the center of the front mesh cover is recessed in the direction of the rear mesh cover to hold the medicine that is not sprayed onto the pipe wall. Exemplarily, the area ratio of the peripheral hollow portion to the central solid portion of the front grille is 1:4.

[0038] Specifically, the guide member needs to be installed at a position 10 to 20 cm behind the nozzle 1; and the outer circumference of the front and rear mesh covers of the guide member needs to be consistent with the outer circumference of the liquid storage tank.

[0039] The operating speed of the gas transported in the natural gas pipeline is generally controlled at 6-15 m / s. It can be understood that the prerequisite for the smooth implementation of the above-mentioned in-service pipeline spraying process is that the spraying device can move in the pipeline under the push of the transported gas. Therefore, the amount of medicine stored in the liquid storage tank 3 cannot be too large to avoid the excessive weight of the entire spraying device equipped with medicine, which affects the movement of the spraying device in the pipeline. Based on this, in step S2, the spraying device sprays the pipeline in sections, and the amount of medicine filled in the spraying device at one time is equal to the amount of medicine required for the pipe section between adjacent compressor stations of the pipeline. When replenishing the medicine, the spraying device is received at the pig receiver 8 of the pipeline.

[0040] The pig launcher 9 and the pig receiver 8 are important components of the pigging and line cleaning equipment, and are installed at the compressor stations at both ends of the pipeline for launching and receiving the pigs. Taking the pipeline including the compressor stations A10, B11, and C12 arranged in sequence as an example, the spraying device starts from the pig launcher 9 at the outlet end of the compressor station A10 and evenly sprays the carried medicine on the inner wall of the pipeline. The spraying device is received at the pig receiver 8 of the compressor station B11. After completing the atomized spraying of the medicine for the pipe section between the compressor stations A10 and B11, an appropriate amount of medicine is replenished to the liquid storage tank 3 in the spraying device at the pig launcher 9 of the compressor station B11, and the spraying device is sent. The spraying device is received at the pig receiver 8 of the compressor station C12 to complete the spraying of the medicine for the pipe section between the compressor stations B11 and B11. Similarly, after replenishing an appropriate amount of natural gas drag reducer to the liquid storage tank 3 in the spraying device at the pig launcher 9 of the compressor station C12, the spraying device is sent, and so on. By continuously replenishing the medicine to the spraying device and ensuring sufficient battery power of the battery 4, the spraying of the drag reducer in the pipe sections between each compressor station is completed, so as to achieve the purpose of uniformly atomizing and adsorbing and forming a film of the medicine on the entire pipe wall of the in-service pipeline.

[0041] Based on the premise that the spraying device is sent through the pig launcher 9 and received by the pig receiver 8, the overall length of the spraying device does not exceed the length of the reducer at the bottom of the pig launcher 9 and the pig receiver 8.

[0042] In order to meet the theoretical thickness of the film formed by the adsorption of the medicine required for the pipeline, the theoretical amount of medicine is calculated according to the following formula 1:

[0043] V = π×d×L 1 ×δ×ξ

[0044] In the formula, d—the inner diameter value of the pipe section where the medicine is injected on site, unit: meter (m). Based on the dimensions of existing natural gas pipelines, the value range is generally within 0.27-1.4 m;

[0045] L 1 —the length of the pipe section where the medicine is injected on site, unit: kilometer (km);

[0046] δ—the film thickness of the agent, in meters (m). Taking the agent as a natural gas drag reducer as an example, it is taken as 1×10 -6 ~1×10 -5 m;

[0047] ξ—the injection coefficient, which is the ratio of the actual dosage to the theoretical dosage.

[0048] It has been verified that the injection coefficient of 1.0 to 1.5 can meet the theoretical thickness requirements for the agent to form a film. Compared with the single-point injection method, the agent dosage can be saved by 25% to 50% (the injection coefficient value for single-point injection is 2.0).

[0049] To prevent wear between the hydraulic pump 2 and the pipeline, the spraying device further includes a protective housing 6. The protective housing 6 is set as a cylindrical shape with the same outer diameter as the liquid storage tank 3. The hydraulic pump 2 and the battery 4 are both arranged inside the protective housing 6. The rear part of the guiding member is connected to the protective housing 6 through a support rod to play a role in supporting and fixing the guiding member.

[0050] To obtain the position of the spraying device in the pipeline in real time, the spraying device further includes a positioning module 5 arranged inside the protective housing 6. The positioning module 5 is configured to determine the position of the spraying device in the pipeline. The positioning module 5 is not limited to using positioning structures such as electromagnetic positioning or off-line navigation.

[0051] At the same time, the spraying device further includes a liquid level sensor 7 arranged inside the liquid storage tank 3 for sensing the liquid level of the agent in the liquid storage tank 3.

[0052] Example 1:

[0053] Implementation object: A natural gas pipeline with a diameter of 1.016 m (inner diameter of the pipeline is 0.979 m) and a total length of about 900 km with the distances between each compressor station (including compressor station A10, compressor station B11, compressor station C12, compressor station D, compressor station E, compressor station F) being 130, 150, 180, 200, 240 km.

[0054] Specific implementation process: First, select a suitable natural gas drag reducer X according to the pipeline to be implemented. The theoretical film thickness of this type of drag reducer for adsorption and film formation is 2 μm. Calculate the theoretical agent dosage range for each pipe section to be 1.2 to 2.2 tons based on the pipe diameter and formula 1, and thus determine that the liquid storage tank 3 includes 2 or 3. The size of a single liquid storage tank 3 is a diameter of 0.96 m and a length of 1 m (a single liquid storage tank 3 can hold 0.72 tons of agent). After filling the liquid storage tank 3 with the selected natural gas drag reducer X, place the spraying device in Figure 1In the pig launcher 9 at the outlet end of the compressor A shown, when placing it, the nozzle 1 of the spraying device needs to face the gas flow direction of the natural gas. Referring to SY / T6383-1999 "Long-distance Natural Gas Pipeline Pigging Operation Regulations", it can travel with the natural gas flow in the pipeline. The gas flow velocity in this section of the pipeline is 10 m / s. Outside the pipeline, the controller enables the battery 4 to supply power to the hydraulic pump 2. The hydraulic pump 2 sucks the natural gas drag reducer X in the liquid storage tank 3 and sprays it through the nozzle 1 in the opposite direction of the natural gas flow. After the natural gas drag reducer X is atomized under the action of the natural gas flow, it is evenly adsorbed on the surrounding walls of the pipeline. After the atomized injection of the natural gas drag reducer X for the pipeline section between the compressor station A10 and the compressor station B11 is completed, the receiving barrel 8 of the compressor station B11 receives the spraying device, and replenishes an appropriate amount of natural gas drag reducer X to the liquid storage tank 3 in the spraying device, replaces the fully charged battery 4, and ensures that the battery capacity can continuously supply power to the hydraulic pump 2 for no less than 8 hours. Then, the spraying device is sent by the pig launcher 9 of the compressor station B11, and the receiving barrel 8 of the compressor station C12 receives the spraying device to complete the atomized injection of the natural gas drag reducer X for the pipeline section between the compressor station B11 and the compressor station C12. Similarly, an appropriate amount of natural gas drag reducer X is replenished to the liquid storage tank 3 in the spraying device at the compressor station C12, the fully charged battery 4 is replaced, and it is ensured that the battery capacity can continuously supply power to the hydraulic pump 2 for no less than 8 hours. Then, the spraying device is sent by the pig launcher 9 of the compressor station C12, and so on. By continuously replenishing the dosage of the natural gas drag reducer X to the spraying device and continuously replacing the fully charged battery 4 to provide sufficient power to the hydraulic pump 2, the spraying of the natural gas drag reducer X in the pipeline sections between each compressor station is completed. The traveling time of the pipeline section equipment between each compressor station ranges from 3.6 to 6.7 hours. After the spraying device travels in the in-service pipeline for 25 hours (only the traveling time, excluding other times such as adding the agent to the liquid storage tank 3 and replacing the battery 4), the purpose of evenly atomizing and adsorbing and forming a film on the entire wall surface of the 900-km in-service natural gas pipeline between 6 compressor stations is achieved.

[0055] According to the dosage of the agent and the theoretical thickness of the liquid film on the pipe wall, through simulation calculation, after using this process to spray the natural gas drag reducer X on the target pipe section, the pipeline resistance reduction rate is 25.3%, and the throughput increase rate reaches 14.2%. The resistance reduction and throughput increase effects and economic benefits are significant.

[0056] Example 2:

[0057] Implementation object: A natural gas pipeline with a diameter of 0.457 m (inner diameter of the pipeline is 0.436 m) and a total length of about 280 km with the distances between each compressor station (including compressor station A10, compressor station B11, compressor station C12, and compressor station D) being 60, 100, and 120 km.

[0058] Specific implementation process: First, select a suitable natural gas drag reducer Y according to the pipeline to be implemented. The theoretical thickness of the film formed by the adsorption of this type of drag reducer is 3μm. Calculate the theoretical dosage range of the drag reducer for each pipe section to be between 0.27 and 0.54 tons according to the pipe diameter and formula 1, and determine whether the number of liquid storage tanks 3 is 1 or 2 accordingly. The size of a single liquid storage tank 3 is a diameter of 0.42m and a length of 1m. After filling the liquid storage tank 3 with the selected natural gas drag reducer Y, place the spraying device in Figure 1 the pig launcher 9 at the outlet end of compressor station A as shown in the figure. Refer to SY / T 6383-1999 "Pigging Operation Regulations for Long-distance Natural Gas Pipelines" to make it travel in the pipeline along with the natural gas flow. The gas flow velocity in this section of the pipeline is 8m / s. Outside the pipe, the controller enables the battery 4 to supply power to the hydraulic pump 2. The hydraulic pump 2 sucks the natural gas drag reducer Y in the liquid storage tank 3 and sprays it through the nozzle 1 in the opposite direction of the gas flow. After the agent is atomized under the action of the natural gas flow, it is evenly adsorbed on the surrounding walls of the pipeline. After the atomized injection of the natural gas drag reducer Y for the pipe section between compressor station A10 and compressor station B11 is completed, receive the spraying device at the pig receiver 8 of compressor station B11, and supplement an appropriate amount of natural gas drag reducer Y to the liquid storage tank 3 in the spraying device at the pig launcher 9 of compressor station B11. Replace the battery 4 that has been fully charged, and ensure that the capacity of the battery 4 can supply power to the hydraulic pump 2 continuously for no less than 6 hours. Then send the spraying device from the pig launcher 9 of compressor station B11, receive the spraying device at the pig receiver 8 of compressor station C12, and complete the atomized injection of the drag reducer for the pipe section between compressor station B11 and compressor station C12. Similarly, supplement an appropriate amount of natural gas drag reducer Y to the liquid storage tank 3 in the spraying device, replace the battery 4 that has been fully charged, and ensure that the capacity of the battery 4 can supply power to the hydraulic pump 2 continuously for no less than 6 hours. Then send the spraying device from the pig launcher 9 of compressor station C12, and so on. By continuously supplementing the dosage of the natural gas drag reducer Y to the spraying device and continuously replacing the fully charged battery 4 to provide sufficient power to the hydraulic pump 2, complete the spraying of the natural gas drag reducer Y in the pipe sections between each compressor station. The traveling time of the equipment in the pipe sections between each compressor station ranges from 2.1 to 4.2 hours. After the spraying device travels in the in-service pipeline for about 10 hours (only the traveling time, excluding other times such as filling the liquid storage tank 3 with the agent and replacing the battery 4), the purpose of evenly atomizing and forming a film of the natural gas drag reducer Y on the entire wall surface of the 280-km in-service pipeline between 4 compressor stations is achieved.

[0059] According to the dosage of the agent and the thickness of the liquid film on the pipe wall being about 3μm, through simulation calculation, it is obtained that after using this process to spray the natural gas drag reducer on the target pipe section, the pipeline drag reduction rate is 28.3%, and the throughput increase rate reaches 15.8%. The drag reduction and throughput increase effect and economic benefits are significant.

[0060] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, various obvious changes, re-adjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to enumerate all implementation manners here. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the claims of the present invention.

Claims

1. A process for spraying an in-service pipeline, wherein a spraying device is used to spray a reagent onto the inner wall of the pipeline, wherein the spraying device comprises a spray head (1), a liquid storage tank (3) and a hydraulic pump (2), and is characterized in that: The in-service pipeline spraying process comprises the following steps: Selecting a suitable agent according to the pipe to be sprayed, determining the theoretical thickness of the film formed by the agent adsorption, and calculating the theoretical agent dosage, thereby determining the size and number of the liquid storage tanks (3); The spraying device is placed in the pipeline and allowed to flow along with the conveying gas flow. The hydraulic pump (2) sprays the agent in the liquid storage tank (3) through the spray head (1) in a direction opposite to the conveying gas flow direction and sprays it onto the inner wall of the pipeline.

2. The in-service pipeline spraying process according to claim 1 is characterized in that: The amount of medicine filled in the spraying device at one time is equal to the amount of medicine required by the pipe section between adjacent compressor stations of the pipeline, and the spraying device replenishes the medicine at the ball launching barrel (9) of the pipeline.

3. The in-service pipeline spraying process according to claim 2 is characterized in that: The calculation formula of the theoretical dosage is: V=π×d×L1×δ×ξ Wherein, d is the inner diameter of the pipe section, L1 is the distance of the pipe section, δ is the film thickness of the agent, and ξ is the injection coefficient.

4. Spraying device, characterized in that, Used in the in-service pipeline spraying process as described in any one of claims 1 to 3, the spraying device comprises a hydraulic pump (2), a spray head (1) and a liquid storage tank (3), the hydraulic pump (2) is connected to the liquid storage tank (3), and the spray head (1) is located outside the liquid storage tank (3) and connected to the hydraulic pump (2).

5. The spraying device according to claim 4, characterized in that: The liquid storage tank (3) is configured to be cylindrical, and the outer diameter of the liquid storage tank (3) is between 90% and 99% of the inner diameter of the pipeline.

6. The spraying device according to claim 4, characterized in that: One or more liquid storage tanks (3) are provided, and adjacent liquid storage tanks (3) are connected via a flexible pressure-resistant hose.

7. The spraying device according to claim 4, characterized in that: A liquid level sensor (7) is arranged inside the liquid storage tank (3).

8. The spraying device according to claim 4, characterized in that: The spraying device further comprises a positioning module (5), which is configured to determine the position of the spraying device within the pipeline.

9. The spraying device according to claim 4, characterized in that: The spraying device further comprises a guide member, which is arranged between the spray head (1) and the liquid storage tank (3) and is used to guide the medicine to the inner wall of the pipeline.

10. The spraying device according to claim 4, characterized in that: The length of the liquid storage tank (3) is 0.5-3 m.

Images