Asphaltene deposition regulation and control system and method and preparation method of magnetic fluid

Abstract

The invention discloses an asphaltene deposition regulation and control system, which comprises a fluid circulation unit, a storage tank for accommodating magnetic fluid, a pumping device for driving the magnetic fluid to circulate, and a test pipe section, the temperature control unit comprises a first water bath heater used for adjusting the temperature of fluid in the storage tank, a second water bath heater used for adjusting the temperature of the test pipe section and a temperature monitoring device arranged on the pipeline; the magnetic trapping unit comprises a magnetic field generating device which is arranged outside a specific section of the test pipe section and is used for generating a controllable magnetic field in the specific section so as to attract magnetic components in the magnetic fluid to enable the magnetic components to be directionally enriched; the monitoring control unit comprises a pressure sensing device used for monitoring pressure parameters of the test pipe section and a control device in signal connection with the pumping device, the temperature control unit and the magnetic field generation device, and the control device is configured to regulate and control the operation state of the magnetic field generation device based on the pressure parameters.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas transportation technology, and particularly relates to a system and method for regulating asphaltene deposition, and a method for preparing magnetofluids. Background Technology In oil and gas gathering and transportation processes, crude oil with high asphaltenes content often faces the problem of asphaltenes deposition during transportation. Asphaltenes molecules have a polycyclic aromatic hydrocarbon skeleton and polar groups. When the temperature and pressure of crude oil change or when it is mixed with other fluids, asphaltenes are prone to flocculation, aggregation, and deposition on the inner wall of pipelines. This deposition leads to increased pipeline pressure drop, reduced effective flow cross-section, and in severe cases, pipeline blockage, affecting normal production.

[0002] Currently, the main methods for preventing asphaltene deposition include: Chemical inhibitor method: This method involves adding surfactants or dispersants to disrupt the aggregated structure of asphaltenes molecules, but it requires continuous high-dose injection and is prone to emulsification problems. Thermal and mechanical cleaning methods: These methods use heat tracing, solvent flushing, or pigging to clean the pipeline, but they require frequent shutdowns, making them difficult and costly to implement. Magnetic field treatment technology: It uses an external magnetic field to change the orientation of asphaltene molecules, but its range of effect is limited and it lacks the ability to couple and control the actual flow process.

[0003] While existing technologies have included research on using magnetic nanoparticles to suppress asphalt deposition, most studies remain at the static experimental stage, lacking a systematic device capable of achieving magnetofluid injection, magnetic field loading, and online monitoring of deposition under flowing conditions. Summary of the Invention

[0004] The purpose of this invention is to solve the problems in the prior art, and to propose a system and method for regulating asphaltene deposition, and a method for preparing magnetic fluid. This invention first discloses an asphaltene deposition control system, comprising: The fluid circulation unit includes a storage tank for containing the magnetic fluid, a pumping device for driving the circulation of the magnetic fluid, and a test pipe section; The temperature control unit includes a first water bath heater for regulating the temperature of the test pipe section, a second water bath heater for regulating the temperature of the non-test pipe section, and a temperature monitoring device installed on the pipeline. The magnetic trapping unit includes a magnetic field generating device disposed outside a specific section of the test tube segment, used to generate a controllable magnetic field within the specific section to attract magnetic components in the magnetofluid and cause them to be directionally enriched. The monitoring and control unit includes a pressure sensing device for monitoring the pressure parameters of the test pipe section and a control device that is signal-connected to the pumping device, the temperature control unit, and the magnetic field generator. The control device is configured to regulate the operating status of the magnetic field generator based on the pressure parameters.

[0005] In the above system, the magnetic field generating device includes a U-shaped electromagnet and an electromagnetic coil wound around it.

[0006] In the above system, the material of the specific section of the test tube is a non-metallic material.

[0007] In the above system, the effective section length of the magnetic trapping unit is 0.4~0.8 meters.

[0008] In the above system, the fluid circulation unit also includes a compressed air source connected to the test pipe section, used to purge the fluid in the pipe back to the storage tank after the experiment.

[0009] Secondly, this invention discloses a method for regulating asphaltene deposition using the above-described system, comprising the following steps: S1: A magnetic fluid containing a complex formed by magnetic nanoparticles and asphaltene is circulated in the test tube section; S2: The temperature control unit establishes a preset temperature environment in the test tube section; S3: Activate the magnetic trapping unit and apply a magnetic field to the specific section to cause the complex to migrate directionally under the action of magnetic force and accumulate on the tube wall; S4: The pressure parameters of the test tube section are monitored in real time by the monitoring and control unit, and the strength of the magnetic field is dynamically adjusted based on the pressure parameters to control the deposition process.

[0010] In the above method, during the magnetic trapping step, when the monitored pressure parameter exceeds a preset threshold, the controller automatically increases the magnetic field strength or initiates a fluid bypass.

[0011] In the above method, the method further includes the step of using compressed gas to purge the residual fluid in the test pipe section to the storage tank after the experiment.

[0012] Thirdly, the present invention discloses a method for preparing a magnetic fluid for the above-described method, comprising: Under inert gas protection and heating conditions, Fe 3+ with Fe 2+ Fe3O4 magnetic nanoparticles are generated by reacting in an alkaline solution at a molar ratio of 2:1. The Fe3O4 magnetic nanoparticles were surface modified by sequentially treating them with 3-aminopropyltriethoxysilane (APTES), oleic acid, and N,N-dimethyloctadecylamine (DMOA). Surface-modified Fe3O4 magnetic nanoparticles are mixed with asphalt-containing crude oil and subjected to shearing or ultrasonic treatment at 50-60°C to form a complex structure between the magnetic nanoparticles and asphalt, thus obtaining the magnetic fluid.

[0013] In the above method, the surface modification step includes first adding 3-aminopropyltriethoxysilane (APTES) at 50°C to form a first polar shell, and then adding oleic acid and N,N-dimethyloctadecylamine (DMOA) at 80°C to form an outer hydrophobic brush.

[0014] The advantages of this invention are: 1. By precisely controlling the movement trajectory of magnetic nanoparticle-asphaltite complexes through magnetic field gradients, the unpredictable random deposition in traditional prevention and control methods is transformed into pre-set directional enrichment, so that asphaltenes can only be deposited in the set collection area. This not only facilitates subsequent centralized cleaning, but more importantly, it completely changes the treatment mode of asphaltenes deposition, shifting from passive cleaning to active guidance.

[0015] 2. The system monitors the deposition status in real time through pressure parameters and automatically adjusts the magnetic field strength or fluid pathway based on this, forming a closed-loop control of "monitoring-judgment-regulation". This adaptive regulation mechanism can dynamically adjust operating parameters according to the deposition progress, ensuring the controllability of the deposition process and effectively preventing the risk of pipeline blockage, thus realizing the intelligent and refined prevention and control process.

[0016] 3. The magnetofluid preparation process and deposition control system in this invention are well-matched. The surface-modified magnetic nanoparticles can effectively combine with asphaltene to form stable complexes, and can also be precisely controlled under the influence of a magnetic field. This deep synergy between materials and processes solves the problem of the disconnect between material properties and engineering applications in traditional methods, providing a completely new technical approach for the treatment of asphaltene deposition. Attached Figure Description

[0017] Figure 1 This is an overall layout diagram of the system in this invention.

[0018] Figure 2 This invention discloses the relationship between the transverse and longitudinal cross sections of the test pipe section and the sensor position.

[0019] In the diagram: 1. Thermometer I, 2. Compressed air source, 3. Thermometer II, 4. Valve I, 5. Valve II, 6. Valve III, 7. Valve IV, 8. Valve V, 9. Valve VI, 10. Pumping device, 11. Thermometer III, 12. Pressure gauge I, 13. Pressure gauge II, 14. First water bath heater, 15. Second water bath heater, 16. Test pipe section, 17. Magnetic field direction, 18. Storage tank, 19. Thermometer IV, 20. Thermometer V, 21. Test pipe section wall, 22. Water bath space, 23. U-shaped electromagnet, 24. Pipe support, 25. Support platform, 26. Support rod, 27. Electromagnetic coil, 28. Current direction, 29. Power supply. Detailed Implementation

[0020] To facilitate understanding of this application and to make the aforementioned objectives, features, and advantages of this application more apparent, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application, and the preferred embodiments of this application are shown in the accompanying drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application. This application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature in the description of this application. The term "multiple" means at least two, such as two, three, etc., unless otherwise explicitly defined in the description of this application. The term "several" means at least one, such as one, two, etc., unless otherwise explicitly defined. It should be noted that when an element is referred to as "fixed to" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementations. Unless otherwise defined, 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 application pertains. The terminology used herein is for the purpose of describing particular implementations only and is not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items. Reference Figures 1-2 This invention provides a bituminous deposition control system, the typical structure of which is as follows: Figure 1As shown, this system achieves controllable adjustment of the location of asphalt deposition through the coordinated operation of four functional units.

[0021] The system comprises a fluid circulation unit, a temperature control unit, a magnetic trapping unit, and a monitoring and control unit. The fluid circulation unit, through a combination of a magnetic fluid storage tank 18 and a pumping device 10, ensures stable closed-loop flow of crude oil containing magnetic nanoparticles within the test tube section 16. This closed-loop design allows for the recycling of the experimental medium, making it particularly suitable for long-term, repetitive studies of deposition mechanisms.

[0022] The temperature control unit includes a first water bath heater 14 and a second water bath heater 15. The first water bath heater 14 independently controls the temperature of the test pipe section 16 through its matching water bath flow space 22. The second water bath heater 15 is used for temperature control of non-test pipe sections to maintain the fluid temperature and make it consistent with the fluid temperature in the storage tank 18. It is used to accurately control the overall temperature of the fluid in the storage tank 18. This discrete design enables the system to establish an accurate temperature gradient between the inlet and outlet of the test pipe section, thereby realistically simulating the temperature drop process in long-distance pipeline transportation.

[0023] The magnetic trapping unit is the core component of the system, and its magnetic field generating device consists of a U-shaped electromagnet 23 and an electromagnetic coil 27. By adjusting the current in the electromagnetic coil 27, a controllable magnetic field can be generated in a specific section of the test pipe section 16. In particular, the pipe material of this specific section is preferably a non-metallic material, such as glass or polytetrafluoroethylene, which minimizes the loss of magnetic flux in the pipe wall and enhances the efficiency of the magnetic field's effect on the fluid inside the pipe.

[0024] In a preferred embodiment, the effective section length of the magnetic trapping unit is designed to be 0.4–0.8 meters. This length range is an optimized result verified through experiments, ensuring that the magnetic particles have sufficient time to migrate to the tube wall under magnetic drive while avoiding excessively long equipment.

[0025] The fluid circulation unit also integrates a compressed air source 2. After the experiment, or when it is necessary to remove sediment, the compressed gas can quickly purge the residual fluid in the test tube section 16 back to the storage tank 18. This function not only facilitates sample recovery and pipeline cleaning, but also greatly shortens the preparation time for switching between different experimental conditions.

[0026] Pressure gauge 12 and pressure gauge 13 of the monitoring and control unit monitor the pressure difference between the two ends of the test pipe section in real time. This data is transmitted to the PLC controller in real time. When the pressure difference exceeds the preset safety threshold, the control system can automatically perform two protective operations: first, increase the magnetic field strength to stabilize the deposit layer; second, automatically open the fluid bypass to reduce the flow rate of the test pipe section, thereby preventing complete blockage of the pipeline due to excessively rapid deposition.

[0027] The present invention also provides a method for controlling asphalt deposition, which achieves precise control of the asphalt deposition process through a systematic operation procedure.

[0028] The method begins with a circulation step: the pumping device 10 is started to establish a circulating flow of the prepared magnetofluid in the test tube section 16. This step provides a dynamic fluid environment that closely approximates actual working conditions for the subsequent deposition process.

[0029] The next step is temperature control: a preset temperature environment is established in the test tube section 16 through a temperature control unit. For example, the inlet temperature can be set to 60°C, and the outlet temperature can be controlled to 40°C by the second water bath heater 15, thereby creating a temperature difference of 20°C, which effectively induces the precipitation of asphalt.

[0030] The core magnetic trapping step is as follows: the magnetic trapping unit is activated, and a magnetic field is applied to a specific section. Under the action of this magnetic field, the "magnetic core-asphalt shell" complex that has formed in the magnetofluid is subjected to a magnetic force pointing towards the pipe wall, thereby separating it from the main fluid, directionally migrating and accumulating on the pipe wall.

[0031] The key monitoring and adjustment steps are as follows: the monitoring and control unit monitors the inlet and outlet pressures of the test pipe section 16 in real time and calculates the pressure difference. When this pressure difference exceeds a preset threshold, the controller will immediately respond automatically and execute one of two strategies: first, increase the current of the electromagnetic coil 27 to enhance the magnetic field strength; second, automatically open the bypass valve to divert part of the fluid. This closed-loop control based on real-time feedback is the core guarantee for the safe and stable operation of this method.

[0032] The method also includes a subsequent purging step: after the experiment, the pumping device 10 is turned off, the compressed gas source 2 is turned on, and the residual fluid in the test tube section 16 is thoroughly purged back into the storage tank 18 using compressed gas. This step not only achieves complete sample recovery, but more importantly, restores the pipeline to a clean state, preparing it for the next experiment.

[0033] The present invention further provides a method for preparing magnetofluids specifically for deposition control systems.

[0034] The preparation process begins with the synthesis of magnetic nanoparticles: under inert gas protection and heating at 75°C, Fe... 3+ with Fe 2+ The reaction is carried out in an alkaline solution at a precise molar ratio of 2:1. This specific molar ratio and reaction conditions are key to obtaining highly magnetically responsive, superparamagnetic Fe3O4 nanoparticles.

[0035] Surface modification was then performed: the obtained Fe3O4 nanoparticles were sequentially treated with APTES, oleic acid, and N,N-dimethyloctadecaneamine in a stepwise manner. First, at 50°C, APTES formed a first polar shell with amino groups on the particle surface through Si-O-Fe bonding. This polar shell provided active sites for hydrogen bonding or coordination with heteroatoms in asphaltene molecules. Subsequently, oleic acid and DMOA were added at 80°C to construct an outer hydrophobic long-chain brush layer. This hydrophobic brush layer significantly improved the dispersion stability of the nanoparticles in the oil phase.

[0036] Finally, the magnetofluid is formed: surface-modified Fe3O4 nanoparticles are mixed with asphaltene-containing crude oil at 50-60℃, and then subjected to high-shear mixing or ultrasonic treatment for 15-20 minutes. During this process, asphaltene spontaneously coats the magnetic nanoparticles, forming a stable "magnetic core-asphaltene shell" complex. This complex possesses both the chemical properties of asphaltene and the magnetic response properties of nanoparticles, making it a material carrier for achieving magnetic field-directed controlled deposition.

[0037] refer to Figure 1 The overall layout of the device includes thermometer 1, thermometer 2, and thermometer 3; compressed air source 2; valve section, including adjustable valve 1 4, valve 2 5, valve 3 6, valve 4 7, valve 5 8, and valve 6 9; pumping device 10; pressure gauge 1 12 and pressure gauge 2 13; first water bath heater 14 and second water bath heater 15; test pipe section 16; magnetic field direction 17; and storage tank 18.

[0038] Figure 2 The diagram shows the relationship between the transverse and longitudinal cross-sections of test tube section 16 and the sensor positions. This section is used to verify the deposition effect of Fe3O4 magnetic nanoparticles + asphaltene. Its specific functions include: Thermometer 4.19 and Thermometer 5.20: Used to test the wall temperature of test tube section 16; Pressure gauge 12 and pressure gauge 23: test the inlet and outlet pressures of test tube section 16, calculate the pressure drop, and indirectly measure the deposition of complexes; Electromagnetic coil 27 generates a suitable magnetic field gradient by applying current in direction 28. Power supply 29 is connected to PLC control cabinet to realize the relationship between magnetic field strength (B) and gradient (B). B / Dynamic adjustment of x); Water bath space 22: Heating the wall temperature of the test tube section 16, maintaining the wall temperature within a certain range, and strengthening the magnetic attraction of the complex. The test pipe section wall 21 is a nestable pipe wall, which allows for the testing of the enrichment performance of different non-metallic materials on asphalt in subsequent experiments. Pipe support 24, support platform 25 and support rod 26 provide support for the device.

[0039] The above embodiments illustrate in detail the specific implementation schemes of the present invention. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this invention should be included within the protection scope of this invention.

[0040] As is known from common technical knowledge, the present invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the above-disclosed embodiments are merely illustrative in all respects and are not the only ones. All changes within the scope of the present invention or equivalent to the scope of the present invention are included in the present invention.

Claims

1. A bituminous deposition control system, characterized in that, include: The fluid circulation unit includes a storage tank (18) for containing the magnetic fluid, a pumping device (10) for driving the circulation of the magnetic fluid, and a test pipe section (16). The temperature control unit includes a first water bath heater (14) for regulating the temperature of the test pipe section (16), a second water bath heater (15) for regulating the temperature of the non-test pipe section, and a temperature monitoring device installed on the pipe. The magnetic trapping unit includes a magnetic field generating device disposed outside a specific section of the test tube section (16) for generating a controllable magnetic field within the specific section to attract magnetic components in the magnetic fluid and concentrate them in a specific direction. The monitoring and control unit includes a pressure sensing device for monitoring the pressure parameters of the test tube section (16) and a control device that is signal-connected to the pumping device (10), the temperature control unit and the magnetic field generator. The control device is configured to regulate the operating status of the magnetic field generator based on the pressure parameters.

2. The system according to claim 1, characterized in that, The magnetic field generating device includes a U-shaped electromagnet (23) and an electromagnetic coil (27) wound around it.

3. The system according to claim 1, characterized in that, The material of the specific section of the test tube section (16) is a non-metallic material.

4. The system according to claim 1, characterized in that, The effective section length of the magnetic trapping unit is 0.4~0.8 meters.

5. The system according to claim 1, characterized in that, The fluid circulation unit also includes a compressed air source (2) connected to the test pipe section (16) for purging the fluid in the pipe back to the storage tank (18) after the experiment.

6. A method for regulating asphaltene deposition using the system described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1: The magnetic fluid containing the complex formed by the magnetic nanoparticles and asphaltene is circulated in the test tube section (16); S2: The temperature control unit establishes a preset temperature environment in the test tube section (16); S3: Activate the magnetic trapping unit and apply a magnetic field to the specific section to cause the complex to migrate directionally under the action of magnetic force and accumulate on the tube wall; S4: The pressure parameters of the test tube section (16) are monitored in real time by the monitoring and control unit, and the strength of the magnetic field is dynamically adjusted based on the pressure parameters to control the deposition process.

7. The method according to claim 6, characterized in that, In the magnetic trapping step, when the monitored pressure parameter exceeds a preset threshold, the controller automatically increases the magnetic field strength or initiates a fluid bypass.

8. The method according to claim 6, characterized in that, The method also includes the step of purging the residual fluid in the test tube section (16) into the storage tank (18) using compressed gas after the experiment.

9. A method for preparing a magnetic fluid for use in the method of claim 6, characterized in that, include: Under inert gas protection and heating conditions, Fe 3+ with Fe 2+ Fe3O4 magnetic nanoparticles are generated by reacting in an alkaline solution at a molar ratio of 2:

1. The Fe3O4 magnetic nanoparticles were surface modified by sequentially treating them with 3-aminopropyltriethoxysilane (APTES), oleic acid, and N,N-dimethyloctadecylamine (DMOA). Surface-modified Fe3O4 magnetic nanoparticles are mixed with asphalt-containing crude oil and subjected to shearing or ultrasonic treatment at 50-60°C to form a complex structure between the magnetic nanoparticles and asphalt, thus obtaining the magnetic fluid.

10. The preparation method according to claim 9, characterized in that, The surface modification steps include first adding 3-aminopropyltriethoxysilane (APTES) at 50°C to form a first polar shell, and then adding oleic acid and N,N-dimethyloctadecylamine (DMOA) at 80°C to form an outer hydrophobic brush.

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