阅读说明：本技术 可回收利用的油品管输磁性纳米减阻剂及制备方法和应用 (Recyclable oil product pipeline magnetic nano drag reducer and preparation method and application thereof ) 是由 刘飞 姚海雷 代晓东 王学武 辛艳萍 刘坤 张程翔 刘清雪 周梦月 于 2021-12-09 设计创作，主要内容包括：本发明涉及油田管输用的减阻剂,特别涉及一种可回收利用的油品管输磁性纳米减阻剂及制备方法和应用,其技术方案是：烯烃单体混合物100份,三乙基铝助催化剂0.5～2份,磁性纳米粒子1.5～3.5份,TiCl-(3)主催化剂3～15份；使用时进行预分散处理,并构建减阻剂回收利用方案,磁感应强度为1T～2T的高强度磁场回收复合减阻剂残余物,高速搅拌剪切30min破坏复合材料中聚合物分子链。本发明的有益效果是：该减阻剂可显著降低管道摩阻、增加管道输量,且具有良好的抗剪切性能,在油品输送到目标区域后,通过构建高强度磁场,可将磁性纳米粒子分离出来,避免其对催化剂/油品质量的影响,同时,回收的磁性纳米粒子经处理后再利用。(The invention relates to a drag reducer for oil field pipeline transportation, in particular to a recyclable oil product pipeline transportation magnetic nano drag reducer, a preparation method and application, and the technical scheme is as follows: 100 parts of olefin monomer mixture, 0.5-2 parts of triethyl aluminum cocatalyst, 1.5-3.5 parts of magnetic nanoparticles and TiCl 3 3-15 parts of a main catalyst; when the composite material is used, pre-dispersion treatment is carried out, a drag reducer recycling scheme is constructed, the composite drag reducer residue is recycled by a high-intensity magnetic field with the magnetic induction intensity of 1T-2T, and polymer molecular chains in the composite material are damaged by high-speed stirring and shearing for 30 min. The invention has the beneficial effects that: the drag reducer can obviously reduce the friction resistance of the pipeline and increase the pipeline output, has good shear resistance, and can construct a high-strength magnetic field to enable magnetic nanoparticles to be generated after an oil product is conveyed to a target areaSeparated out to avoid the influence on the quality of the catalyst/oil product, and meanwhile, the recycled magnetic nano particles are recycled after being processed.)

1. A recyclable oil product pipeline magnetic nano drag reducer is characterized by comprising the following raw materials in parts by weight: 100 parts of olefin monomer mixture, 0.5-2 parts of triethyl aluminum cocatalyst, 1.5-3.5 parts of magnetic nanoparticles and TiCl₃3-15 parts of a main catalyst.

2. The method for preparing the recyclable magnetic nano drag reducer for oil product pipeline as defined in claim 1, is characterized by comprising the following steps:

putting a fully dried polymerization reactor into an ethylene glycol environment, controlling the temperature at minus 10-minus 3 ℃, adding 100 parts of olefin monomer mixture into the polymerization reactor under the condition of magnetic stirring, then adding 80-120 parts of normal hexane as a solvent, and then adding 0.5-2 parts of triethyl aluminum cocatalyst; then slowly adding 1.5-3.5 parts of magnetic nanoparticles, increasing the stirring speed, and stirring until the magnetic nanoparticles are completely mixed; then adding 3-15 parts of TiCl into the polymerization reactor₃And (3) adjusting the environmental temperature of ethylene glycol to be minus 5-5 ℃ by using a main catalyst, and reacting for 54-72 h to obtain a polyolefin bulk solid containing magnetic nanoparticles as the magnetic nano drag reducer for oil product pipeline transportation.

3. The method for preparing the recyclable magnetic nano drag reducer for oil product pipeline according to claim 1 or 2, characterized by comprising the following steps: the olefin monomer mixture comprises alpha-octene, 1-decene and alpha-dodecene, and the proportion of each component is as follows, in parts by weight: the range of the alpha-octene to 1-decene is 1: 2-3: 1; total weight of α -octene and 1-decene: the range of alpha-dodecene is 2:8 to 5: 5.

4. The method for preparing the recyclable magnetic nano drag reducer for oil product pipeline according to claim 3, wherein the method comprises the following steps: the preparation method of the magnetic nanoparticles comprises the following steps of:

taking 0.5-3 parts of Fe₃O₄Adding the nano particles into 150 parts of absolute ethyl alcohol, stirring at a constant speed, and ultrasonically dispersing and uniformly mixing at normal temperature to obtain a fully dispersed suspension; adding the suspension into a five-neck flask, and introducing nitrogen under the conditions of 30 ℃ and constant stirring; during the period, the pH is continuously monitored by a pH meter and the pH value of the suspension is adjusted to be neutral by HCl solution; slowly dropwise adding TEOS solution, continuously stirring, adjusting the pH value to 8-9, continuously stirring, finishing the reaction, cleaning the product with deionized water for multiple times, and drying in vacuum at 50 ℃ to obtain SiO coated on the surface₂Fe of the layer₃O₄@SiO₂The magnetic nanoparticles are named as nanoparticles I;

taking 2-3 parts of hydrophobic SiO₂Adding the nano particles into 200 parts of absolute ethyl alcohol, stirring at a constant speed, and ultrasonically dispersing and uniformly mixing at normal temperature to obtain a fully dispersed suspension; adding the suspension into a three-neck flask, slowly dropwise adding 5-6 parts of organic amine surfactant, continuously stirring to finish the reaction, washing the product with absolute ethyl alcohol for multiple times, and vacuum-drying at 50 ℃ to obtain SiO coated with an organic amine surfactant layer on the surface₂@ organic amine surfactant nanoparticle, named nanoparticle two;

adding 5-10 parts of the second nano particle into 100 parts of HCl solution with the pH value of 4-5, stirring at a constant speed, and ultrasonically dispersing and uniformly mixing at normal temperature to obtain a fully dispersed first suspension system; taking 1-2 parts of Fe₃O₄@SiO₂Adding the magnetic nanoparticles into 100 parts of absolute ethyl alcohol, stirring at a constant speed, and ultrasonically dispersing and uniformly mixing at normal temperature to obtain a fully dispersed second suspension system;

and adding the first suspension system into a three-neck flask, stirring at a constant speed, then slowly dropwise adding a second suspension system, continuously stirring, adjusting the pH value to 4-5, continuously stirring, adjusting the pH value of the system to 9-10, continuously stirring until the reaction is finished, cleaning the product with absolute ethyl alcohol for multiple times, and then drying in vacuum at 50 ℃ to obtain the pH value responsive magnetic nanoparticles with a double-layer coating structure.

5. The method for preparing the recyclable magnetic nano drag reducer for oil product pipeline according to claim 4, wherein the method comprises the following steps: the organic amine surfactant is hexadecylamine or octadecylamine.

6. The method for preparing the recyclable magnetic nano drag reducer for oil product pipeline according to claim 5, wherein the method comprises the following steps: the full utilization of the drag reducer is realized through pre-dispersion treatment, and the pre-dispersion treatment comprises the following specific steps in parts by weight:

and taking the obtained polyolefin bulk solid containing the magnetic nanoparticles out of the polymerization reactor, shearing the polyolefin bulk solid with scissors, dissolving 20 to 60 parts of the polyolefin bulk solid containing the magnetic nanoparticles into 100 parts of oil phase, and magnetically stirring the mixture for 50 to 100 hours at the room temperature and at the air isolation condition at 80 to 120r/min until the mixture is completely dissolved to construct a composite drag reducer mother liquor system.

7. The method for preparing the recyclable magnetic nano drag reducer for oil product pipeline according to claim 6, wherein the method comprises the following steps: the oil phase is n-heptane, diesel oil or white oil.

8. The use of the recyclable oil pipeline magnetic nano drag reducer as defined in claim 7, wherein: the method for recycling the drag reducer for oil product transportation after the composite drag reducer mother liquor system is applied comprises the following processes in parts by weight:

adding 1 part of the composite drag reducer mother liquor system into 10000 parts of diesel oil, performing pipe conveying shearing according to the actual oil conveying flow rate, and performing pump shearing for multiple times to simulate the oil containing drag reducer after the whole conveying process is completed;

secondly, placing the oil product containing the drag reducer after the conveying is completed in a beaker, and efficiently separating magnetic particles contained in the oil product by constructing a high-strength magnetic field I;

thirdly, adding 1 part of the recovered magnetic particles into 10 parts of hydrochloric acid, stirring and shearing at a high speed to realize high damage of polymer molecular chains in the composite material, and simultaneously, changing the lipophilicity of the surfaces of the magnetic particles into hydrophilicity in an acidic environment to realize the separation of the magnetic particles and the sheared and damaged polymer chains; separating out hydrophilic magnetic particles through a constructed high-strength magnetic field II, adding the separated hydrophilic magnetic particles into a weak alkaline liquid system with the pH value of 9-10, continuously stirring for 2h until the reaction is finished, washing the product with absolute ethyl alcohol for multiple times, and drying in vacuum at 50 ℃ to obtain the recyclable pH value responsive magnetic nanoparticles with a double-layer coating structure for preparing the next batch of polyolefin bulk solids containing the magnetic nanoparticles.

9. The use of the recyclable magnetic nano drag reducer for oil pipeline as claimed in claim 8, wherein: the magnetic induction intensity of the high-intensity magnetic field I is 0.5T-2T, and the magnetic induction intensity of the high-intensity magnetic field II is 0.2T-0.8T.

10. The use of the recyclable magnetic nano drag reducer for oil pipeline as claimed in claim 8, wherein: the concentration of the hydrochloric acid is 1-5% by mass percent.

Technical Field

The invention relates to a drag reducer for oil field pipeline transportation, in particular to a recyclable oil product pipeline transportation magnetic nano drag reducer and a preparation method and application thereof.

Background

At present, the accumulated length of oil and gas pipelines which are built and operated in China exceeds 16 ten thousand kilometers, the crude oil conveyed by the pipelines accounts for more than 70 percent of the crude oil yield on the land of China, and the conveying capacity of finished oil pipelines exceeds 1.5 hundred million tons per year. Because the pipeline friction causes fluid power loss, continuous pressurization is needed in the oil conveying process, and a large amount of energy is consumed. The technology of adding the oil product drag reducer into the pipeline can greatly reduce the friction loss and realize the safe and efficient transportation of the oil product.

At present, commercial oil drag reducers are mainly ultra-high molecular weight short side chain poly-alpha-olefins, and the larger the molecular weight and the higher the degree of non-crystallization, the better the drag reduction effect is. From the application process of the polyalphaolefin drag reducer, because energy needs to be continuously supplemented by pressurizing through a pump in the process of pipeline transportation of oil products, and a high-speed gradient, a turbulent fluctuation or a high-shear environment exists, such as the pump, an elbow and the like, the high-molecular drag reducer can undergo irreversible mechanical degradation, and a plurality of stations for supplementing the drag reducer are arranged on the pipeline to maintain the corresponding drag reduction effect.

Aiming at the problem, the Chinese patent application No. 201510577396.0 with the patent name of 'spherical nano SiO 2-polyolefin composite drag reducer solution in-situ synthesis method' proposes the composite drag reducer by spherical nano SiO₂Alpha octene and alpha dodecene as monomer and solution in-situ polymerization process to disperse and modify nanometer SiO in the polymerized monomer of alpha octene and alpha dodecene₂The composite oil drag reducer with good anti-shearing capability and drag reduction performance is prepared. The Chinese patent application No. 201811081789.2, named "blend synthesis method of expanded graphite and polyalphaolefin composite oil drag reducer", mentions that the expanded graphite after being treated is added in the crushing process of polyalphaolefin, and the constructed expanded graphite/polyalphaolefin composite oil drag reduction material has excellent mechanical properties, can disperse shearing force in the drag reduction process and reduce degradation loss. The Chinese patent application No. 201610156047.6, entitled "method for preparing oil-based composite oil product drag reducer from waste clay for decolorization of finished oil", proposes that a titanate coupling agent is used to improve the surface properties of the waste clay, a certain nonpolar structure is formed on the surface of the waste clay through a zwitterionic surfactant and a cationic surfactant, and the waste clay is assisted to enter the microstructure of the polyolefin drag reducer to form the composite drag reducer. Utilizing the nano-scale structure of the spent bleaching earth, passing through the polymer and Al of the spent bleaching earth₂O3 and SiO₂The interaction between the unit structures can solve the problem of irreversible degradation of a polymer chain under the shearing action, and the shearing resistance of the oil product drag reducer is improved.

The composite drag reducer system provided by the method has good drag reduction performance, and the types of the composite drag reducers mainly related to comprise spherical nano SiO₂Although the composite drag reducer overcomes the defect of poor shearing resistance of a polymer drag reducer, a large number of particles with fine volume are dispersed in oil products and are difficult to remove as mechanical impurities before oil refining, catalyst poisoning is caused, the quality of the oil products is influenced, and the popularization and the application of the composite drag reducer are influenced.

Disclosure of Invention

The invention aims to provide a recyclable oil product pipeline transportation magnetic nano drag reducer, a preparation method and application thereof, aiming at the defects in the prior art, the drag reducer can obviously reduce the pipeline friction resistance and increase the pipeline transportation capacity, has good shear resistance, can separate magnetic nano particles by constructing a high-strength magnetic field after oil products are transported to a target area, and avoids the influence of the high-strength magnetic field on the quality of a catalyst/oil product, and meanwhile, the recycled magnetic nano particles are recycled after being processed to participate in the preparation of the next batch of composite drag reducer containing the magnetic nano particles.

The invention provides a recyclable oil product pipeline magnetic nano drag reducer, which adopts the technical scheme that the recyclable oil product pipeline magnetic nano drag reducer is prepared from the following raw materials in parts by weight: 100 parts of olefin monomer mixture, 0.5-2 parts of triethyl aluminum cocatalyst, 1.5-3.5 parts of magnetic nanoparticles and TiCl₃3-15 parts of a main catalyst.

The preparation method of the recyclable oil product pipeline magnetic nano drag reducer comprises the following steps:

putting a fully dried polymerization reactor into an ethylene glycol environment, controlling the temperature at minus 10-minus 3 ℃, adding 100 parts of olefin monomer mixture into the polymerization reactor under the condition of magnetic stirring, then adding 80-120 parts of normal hexane as a solvent, and then adding 0.5-2 parts of triethyl aluminum cocatalyst; then slowly adding 1.5-3.5 parts of magnetic nanoparticles, increasing the stirring speed, and stirring until the magnetic nanoparticles are completely mixed; then adding 3-15 parts of TiCl into the polymerization reactor₃And (3) adjusting the environmental temperature of ethylene glycol to be minus 5-5 ℃ by using a main catalyst, and reacting for 54-72 h to obtain a polyolefin bulk solid containing magnetic nanoparticles as the magnetic nano drag reducer for oil product pipeline transportation.

Preferably, the olefin monomer mixture comprises alpha-octene, 1-decene and alpha-dodecene, and the proportion of each component is as follows according to the parts by weight: the range of the alpha-octene to 1-decene is 1: 2-3: 1; total weight of α -octene and 1-decene: the range of alpha-dodecene is 2:8 to 5: 5.

Preferably, the preparation method of the magnetic nanoparticles comprises the following steps of:

taking 0.5-3 parts of Fe₃O₄Adding the nano particles into 150 parts of absolute ethyl alcohol, stirring at a constant speed, and ultrasonically dispersing and mixing uniformly at normal temperature to obtain fully dispersed nano particlesThe suspension of (a); adding the suspension into a five-neck flask, and introducing nitrogen under the conditions of 30 ℃ and constant stirring; during the period, the pH is continuously monitored by a pH meter and the pH value of the suspension is adjusted to be neutral by HCl solution; slowly dropwise adding TEOS solution, continuously stirring, adjusting the pH value to 8-9, continuously stirring, finishing the reaction, cleaning the product with deionized water for multiple times, and drying in vacuum at 50 ℃ to obtain SiO coated on the surface₂Fe of the layer₃O₄@SiO₂The magnetic nanoparticles are named as nanoparticles I;

taking 2-3 parts of hydrophobic SiO₂Adding the nano particles into 200 parts of absolute ethyl alcohol, stirring at a constant speed, and ultrasonically dispersing and uniformly mixing at normal temperature to obtain a fully dispersed suspension; adding the suspension into a three-neck flask, slowly dropwise adding 5-6 parts of organic amine surfactant, continuously stirring to finish the reaction, washing the product with absolute ethyl alcohol for multiple times, and vacuum-drying at 50 ℃ to obtain SiO coated with an organic amine surfactant layer on the surface₂@ organic amine surfactant nanoparticle, named nanoparticle two;

adding 5-10 parts of the second nano particle into 100 parts of HCl solution with the pH value of 4-5, stirring at a constant speed, and ultrasonically dispersing and uniformly mixing at normal temperature to obtain a fully dispersed first suspension system; taking 1-2 parts of Fe₃O₄@SiO₂Adding the magnetic nanoparticles into 100 parts of absolute ethyl alcohol, stirring at a constant speed, and ultrasonically dispersing and uniformly mixing at normal temperature to obtain a fully dispersed second suspension system;

and adding the first suspension system into a three-neck flask, stirring at a constant speed, then slowly dropwise adding a second suspension system, continuously stirring, adjusting the pH value to 4-5, continuously stirring, adjusting the pH value of the system to 9-10, continuously stirring until the reaction is finished, cleaning the product with absolute ethyl alcohol for multiple times, and then drying in vacuum at 50 ℃ to obtain the pH value responsive magnetic nanoparticles with a double-layer coating structure.

Preferably, the organic amine surfactant is hexadecylamine or octadecylamine.

Preferably, the drag reducer is fully utilized through pre-dispersion treatment, and the pre-dispersion treatment comprises the following specific steps in parts by weight:

and taking the obtained polyolefin bulk solid containing the magnetic nanoparticles out of the polymerization reactor, shearing the polyolefin bulk solid with scissors, dissolving 20 to 60 parts of the polyolefin bulk solid containing the magnetic nanoparticles into 100 parts of oil phase, and magnetically stirring the mixture for 50 to 100 hours at the room temperature and at the air isolation condition at 80 to 120r/min until the mixture is completely dissolved to construct a composite drag reducer mother liquor system.

Preferably, the oil phase is n-heptane, diesel or white oil.

The application of the recyclable oil product pipeline magnetic nano drag reducer provided by the invention is to recycle the drag reducer for oil product transportation after a composite drag reducer mother liquor system is applied, and the process comprises the following steps of:

adding 1 part of the composite drag reducer mother liquor system into 10000 parts of diesel oil, performing pipe conveying shearing according to the actual oil conveying flow rate, and performing pump shearing for multiple times to simulate the oil containing drag reducer after the whole conveying process is completed;

secondly, placing the oil product containing the drag reducer after the conveying is completed in a beaker, and efficiently separating magnetic particles contained in the oil product by constructing a high-strength magnetic field I;

thirdly, adding 1 part of the recovered magnetic particles into 10 parts of hydrochloric acid, stirring and shearing at a high speed to realize high damage of polymer molecular chains in the composite material, and simultaneously, changing the lipophilicity of the surfaces of the magnetic particles into hydrophilicity in an acidic environment to realize the separation of the magnetic particles and the sheared and damaged polymer chains; separating out hydrophilic magnetic particles through a constructed high-strength magnetic field II, adding the separated hydrophilic magnetic particles into a weak alkaline liquid system with the pH value of 9-10, continuously stirring for 2h until the reaction is finished, washing the product with absolute ethyl alcohol for multiple times, and drying in vacuum at 50 ℃ to obtain the recyclable pH value responsive magnetic nanoparticles with a double-layer coating structure for preparing the next batch of polyolefin bulk solids containing the magnetic nanoparticles.

Preferably, the magnetic induction of the first high-intensity magnetic field is 0.5T to 2T, and the magnetic induction of the second high-intensity magnetic field is 0.2T to 0.8T.

Preferably, the hydrochloric acid concentration is 1 to 5% by mass.

Compared with the prior art, the invention has the following beneficial effects:

the drag reducer prepared by the invention is nano Fe₃O₄Magnetic nanoparticles with a multi-layer composite structure and organic amine groups covered on the surface are taken as a reinforcing agent, wherein the nano Fe₃O₄Endowing the particles with a magnetic response function, wherein the organic amine group covered on the surface can realize reversible conversion when the pH value changes, and endowing the particles with a pH value response function; the reinforcing agent is used for participating in the process of synthesizing the poly-alpha-olefin by using the olefin monomer mixture, the magnetic nanoparticles are introduced to be fully wrapped by the poly-alpha-olefin molecular chain, the rigidity of the organic molecular chain can be effectively improved, and the extension of the organic molecular chain is promoted;

secondly, when the drag reducer is used on site, the drag reducer can play a good drag reduction role after being added into an oil product, and the prepared polyolefin bulk solid containing magnetic nanoparticles has a low dispersion speed in the oil product;

in the invention, the magnetic nanoparticles with pH value responsiveness are used as the reinforcing agent and are fully wrapped by the poly-alpha-olefin molecular chain to prepare the polyolefin bulk solid containing the magnetic nanoparticles to construct the composite drag reducer, and compared with the composite drag reducer constructed by using common particles as the reinforcing agent, the composite drag reducer has more advantages.

Drawings

FIG. 1 is a graph of the effect of reaction temperature on the drag reduction ratio of a composite drag reducer;

FIG. 2 is a graph of the effect of different high speed stirring shear rates on magnetic nanoparticle reuse efficiency;

FIG. 3 is a graph comparing the shear resistance of drag reducers prepared in example 1 with that of polyalphaolefin drag reducers;

fig. 4 is a graph comparing the shear resistance of drag reducers prepared in example 2 with that of polyalphaolefin drag reducers.

Detailed Description

The following description of the preferred embodiments of the present invention is provided for the purpose of illustration and description, and is in no way intended to limit the invention.

Example 1, the recyclable magnetic nano drag reducer for oil pipeline provided by the invention comprises the following raw materials in parts by weight: 100 parts of olefin monomer mixture, 0.5 part of triethyl aluminum cocatalyst, 1.5 parts of magnetic nano particles and TiCl₃3 parts of a main catalyst;

the preparation method of the recyclable oil product pipeline magnetic nano drag reducer comprises the following steps:

putting a fully dried polymerization reactor into an ethylene glycol environment, controlling the temperature at-5 ℃, adding 100 parts of olefin monomer mixture into the polymerization reactor under the condition of magnetic stirring at 150r/min, wherein the mass ratio of alpha-octene to 1-decene to alpha-dodecene is 1:2:6, then adding 90 parts of n-hexane as a solvent, and adding 1 part of triethylaluminum cocatalyst; at this time, 2 parts of Fe was slowly added₃O₄@SiO₂@ hexadecylamine magnetic nano particles, increasing the stirring speed to 600r/min, and stirring for 2h until the particles are completely mixed; 5 parts of TiCl are then introduced into the polymerization vessel₃A main catalyst, which adjusts the ethylene glycol environment to 0 ℃ and reacts for 60 hours to obtain a polyolefin block solid containing magnetic nanoparticles, namely a recyclable drag reducer for oil product transportation, wherein FIG. 1 shows the influence of the reaction temperature on the drag reduction rate of the composite drag reducer;

the drag reducer prepared in example 1 and the polyalphaolefin drag reducer were purchased from galleries wept pipeline technologies ltd and compared with the shear resistance effect of the drag reducer by a centrifugal pump of a loop system; fig. 3 is a schematic comparison of the shear resistance of the drag reducer prepared in example 1 with that of a polyalphaolefin drag reducer.

Fe mentioned in the present invention₃O₄@SiO₂The preparation method of the @ hexadecylamine magnetic nanoparticles comprises the following steps:

taking 1.5 parts of Fe₃O₄Adding the nano particles into 150 parts of absolute ethyl alcohol, uniformly stirring for 10 min at a constant speed of 200r/min, and uniformly mixing by ultrasonic dispersion at normal temperature for 30min to obtain a fully dispersed suspension system. The suspension was charged into a 250mL five-necked flask and purged with nitrogen at 30 ℃ under constant stirring for 0.5 h. During this time, the pH was monitored with a pH meter and the pH of the suspension was adjusted to neutrality with 2 mol/L HCl solution. Then slowly dripping 3 mL of TEOS solution with the mass fraction of 7 percent, in particular tetraethyl silicate solution; continuously stirring for 10 min, adjusting the pH value to 9, and continuously stirring for 12h to finish the reaction; washing the product with deionized water for 3 times, and vacuum drying at 50 deg.C for 12h to obtain "surface coated SiO₂Fe of the layer₃O₄@SiO₂Magnetic nanoparticles ";

taking 3 parts of hydrophobic SiO₂Adding the nano particles into 200 parts of absolute ethyl alcohol, uniformly stirring for 10 min at a constant speed of 180r/min, and uniformly mixing by ultrasonic dispersion for 30min at normal temperature to obtain a fully dispersed suspension system; adding the suspension system into a 250mL three-neck flask, slowly dropwise adding 5 parts of hexadecylamine into the suspension system, and continuously stirring for 8 hours to finish the reaction; washing the product with anhydrous ethanol for 3 times, and vacuum drying at 50 deg.C for 12h to obtain SiO with surface coated with hexadecylamine layer₂@ hexadecylamine nanoparticles ";

taking 6 parts of the synthesized SiO with the surface coated with the hexadecylamine layer₂Adding @ hexadecylamine nano particles into 100 parts of HCl solution with the pH value of 4, uniformly stirring at 200r/min for 10 min, ultrasonically dispersing at normal temperature for 30min, and uniformly mixing to obtain a fully dispersed suspension system 1; taking 2 parts of' surface coating SiO₂Fe of the layer₃O₄@SiO₂Adding the magnetic nanoparticles into 100 parts of absolute ethyl alcohol, uniformly stirring for 10 min at a constant speed of 200r/min, ultrasonically dispersing at normal temperature for 10 min, and uniformly mixing to obtain a fully dispersed suspension system 2;

adding the suspension system 1 into a 250mL three-neck flask, uniformly stirring at 200r/min for 4 min, and then slowly dropwise adding the suspension system 2;continuously stirring for 10 min, adjusting the pH value to 4, and continuously stirring for 12h to finish the reaction; washing the product with deionized water for 3 times, and vacuum drying at 50 deg.C for 12h to obtain Fe with surface covered with hexadecylamine layer and double-layer coating structure₃O₄@SiO₂@ hexadecylamine magnetic nanoparticles.

The recyclable oil product pipeline magnetic nano drag reducer can be subjected to pre-dispersion treatment before use to realize efficient utilization of the drag reducer, and the pre-dispersion treatment comprises the following specific steps in parts by weight:

and taking the obtained polyolefin bulk solid containing the magnetic nanoparticles out of the polymerization reactor, shearing the polyolefin bulk solid with scissors, dissolving 20 to 60 parts of the polyolefin bulk solid containing the magnetic nanoparticles into 100 parts of oil phase, and magnetically stirring the mixture for 50 to 100 hours at the room temperature and at the air isolation condition at 80 to 120r/min until the mixture is completely dissolved to construct a composite drag reducer mother liquor system.

Preferably, the oil phase is n-heptane, diesel oil or white oil, and more preferably, the oil phase is 0# diesel oil, 5# white oil, 15# white oil or n-heptane.

In addition, the application of the recyclable oil product pipeline magnetic nano drag reducer provided by the invention is as follows: the composite drag reducer mother liquor system can be used for recycling the drag reducer for oil product transportation, and the method comprises the following steps of:

adding 1 part of the composite drag reducer mother liquor system into 10000 parts of diesel oil, performing pipe conveying shearing for 10 days according to the actual oil conveying flow rate, performing pump shearing for 2 times, and simulating the oil containing drag reducer after the whole conveying process is completed;

secondly, the oil product containing the drag reducer after the conveying is simulated is placed in a beaker, and a high-strength magnetic field I is constructed, so that magnetic nanoparticles contained in the oil product can be efficiently separated out, the catalyst poisoning caused by the magnetic nanoparticles is avoided, and the quality of the oil product is protected;

thirdly, adding 1 part of the recycled magnetic nano particles into 10 parts of hydrochloric acid, stirring and shearing at a high speed of 8000 r/min-12000 r/min for 30min to realize the high damage of polymer molecular chains in the composite material, meanwhile, the surface of the magnetic nano particles is changed from lipophilicity to hydrophilicity under the acidic environment, the separation of the magnetic nano particles and the high molecular chains after being sheared and damaged is realized, separating out hydrophilic magnetic nanoparticles by a constructed high-strength magnetic field II, adding the separated hydrophilic magnetic nanoparticles into a weak alkaline liquid system with the pH value of 9-10, continuously stirring for 2 hours until the reaction is finished, washing the product with absolute ethyl alcohol for multiple times, vacuum drying at 50 deg.C for 12h to obtain reusable pH value responsive magnetic nanoparticles with double-layer coating structure, can be used for preparing the next batch of polyolefin bulk solids containing magnetic nanoparticles, and FIG. 2 shows the influence of different high-speed stirring shear rates on the reutilization rate of the magnetic nanoparticles.

The magnetic induction of the first high-intensity magnetic field is 0.5T to 2T, the magnetic induction of the second high-intensity magnetic field is 0.2T to 0.8T, and more preferably, the magnetic induction of the high-intensity magnetic field 1 is 1T to 2T, and the magnetic induction of the high-intensity magnetic field 2 is 0.3T to 0.5T; the concentration of the hydrochloric acid is 1 to 5 percent, and the concentration range of the hydrochloric acid is more preferably 2 to 4 percent by mass.

Example 2, the recyclable magnetic nano drag reducer for oil pipeline provided by the invention comprises the following raw materials in parts by weight: 100 parts of olefin monomer mixture, 2 parts of triethyl aluminum cocatalyst, 3.5 parts of magnetic nano particles and TiCl₃15 parts of a main catalyst;

the preparation method of the recyclable oil product pipeline magnetic nano drag reducer comprises the following steps:

putting the fully dried polymerization reactor into an ethylene glycol environment, controlling the temperature at-5 ℃, and adding 100 parts of olefin monomer mixture into the polymerization reactor under the condition of magnetic stirring at 150r/min, wherein the mass ratio of alpha-octene to 1-decene to alpha-dodecene is 3:1: 4; then adding 90 parts of n-hexane as a solvent, and then adding 1 part of triethyl aluminum cocatalyst; at this time, 2 parts of Fe was slowly added₃O₄@SiO₂@ octadecylamine magnetic nanoparticles, increasing the stirring speed to 600r/min, and stirring for 2 hours until the particles are completely mixed; 5 parts of TiCl are then introduced into the polymerization vessel₃The main catalyst is used for adjusting the ethylene glycol environment to 0 ℃ and reacting for 60 hours to obtain the magnetic nanoparticlesThe polyolefin block solid is the recyclable drag reducer for oil product transportation.

The drag reducer prepared in example 2 and the polyalphaolefin drag reducer were purchased from galleries weppel pipeline technologies ltd and were subjected to shear contrast by a centrifugal pump of a loop system to obtain the shear effect of the drag reducer, and fig. 4 is a graph comparing the shear effect of the drag reducer prepared in example 2 and the polyalphaolefin drag reducer.

The difference from the embodiment 1 is that: fe with double-layer coating structure and surface covered with octadecylamine layer₃O₄@SiO₂The synthesis steps of the @ octadecylamine magnetic nanoparticles are as follows:

taking 3 parts of Fe₃O₄Adding the nano particles into 150 parts of absolute ethyl alcohol, uniformly stirring for 8 min at a constant speed of 180r/min, and uniformly mixing by ultrasonic dispersion at normal temperature for 30min to obtain a fully dispersed suspension system; adding the suspension system into a 250mL five-neck flask, and introducing nitrogen for 0.5h at 30 ℃ under the condition of constant stirring; during the process, the pH value is continuously monitored by a pH meter and is adjusted to be neutral by 2 mol/L HCl solution; then slowly dripping 3 mL of TEOS solution with the mass fraction of 7%; continuously stirring for 10 min, adjusting the pH value to 8, and continuously stirring for 12h to finish the reaction; washing the product with deionized water for 3 times, and vacuum drying at 50 deg.C for 12h to obtain "surface coated SiO₂Fe of the layer₃O₄@SiO₂Magnetic nanoparticles ";

taking 2 parts of hydrophobic SiO₂Adding the nano particles into 200 parts of absolute ethyl alcohol, uniformly stirring for 8 min at a constant speed of 200r/min, and uniformly mixing by ultrasonic dispersion at normal temperature for 30min to obtain a fully dispersed suspension system; adding the suspension system into a 250mL three-neck flask, slowly dropwise adding 6 parts of octadecylamine, and continuously stirring for 8 hours to finish the reaction; washing the product with absolute ethyl alcohol for 3 times, and vacuum drying at 50 deg.C for 12h to obtain SiO with octadecylamine layer coated on the surface₂@ octadecylamine nanoparticles ";

taking 10 parts of the synthesized SiO with the octadecylamine layer coated on the surface₂Adding @ octadecylamine nanoparticles into 100 parts of HCl solution with pH value of 4, uniformly stirring at 190r/min for 8 min, ultrasonically dispersing at normal temperature for 30min, and uniformly mixing to obtain fully dispersed suspensionSystem 1; taking 2 parts of' surface coating SiO₂Fe of the layer₃O₄@SiO₂Adding the magnetic nanoparticles into 100 parts of absolute ethyl alcohol, uniformly stirring for 8 min at a constant speed of 180r/min, ultrasonically dispersing at normal temperature for 10 min, and uniformly mixing to obtain a fully dispersed suspension system 2;

adding the suspension system 1 into a 250mL three-neck flask, uniformly stirring for 3 min at 180r/min, and then slowly dropwise adding the suspension system 2; continuously stirring for 10 min, adjusting the pH value to 5, and continuously stirring for 12h to finish the reaction; washing the product with deionized water for 3 times, and vacuum drying at 50 deg.C for 12h to obtain Fe with double-layer coating structure with surface covered with octadecylamine layer₃O₄@SiO₂@ octadecylamine magnetic nanoparticles.

Example 3, the recyclable magnetic nano drag reducer for oil pipeline provided by the invention comprises the following raw materials in parts by weight: 100 parts of olefin monomer mixture, 1 part of triethyl aluminum cocatalyst, 2.5 parts of magnetic nano particles and TiCl₃9 parts of a main catalyst;

the preparation method of the recyclable oil product pipeline magnetic nano drag reducer comprises the following steps:

putting the fully dried polymerization reactor into an ethylene glycol environment, controlling the temperature at-5 ℃, and adding 100 parts of olefin monomer mixture into the polymerization reactor under the condition of magnetic stirring at 150r/min, wherein the mass ratio of alpha-octene to 1-decene to alpha-dodecene is 1:1: 1; then adding 90 parts of n-hexane as a solvent, and then adding 1 part of triethyl aluminum cocatalyst; at this time, 2 parts of Fe was slowly added₃O₄@SiO₂@ octadecylamine magnetic nanoparticles, increasing the stirring speed to 600r/min, and stirring for 2 hours until the particles are completely mixed; 5 parts of TiCl are then introduced into the polymerization vessel₃And (3) adjusting the ethylene glycol environment to 0 ℃ by using a main catalyst, and reacting for 60 hours to obtain a polyolefin bulk solid containing magnetic nanoparticles, namely the recyclable drag reducer for oil product transportation.

Wherein the surface is covered with octadecylamine layer and has double-layer coating structure Fe₃O₄@SiO₂@ octadecylamine magnetic nanoparticlesThe synthesis steps are as follows:

taking 0.5 part of Fe₃O₄Adding the nano particles into 150 parts of absolute ethyl alcohol, uniformly stirring for 10 min at a constant speed of 180r/min, and uniformly mixing by ultrasonic dispersion at normal temperature for 30min to obtain a fully dispersed suspension system; adding the suspension system into a 250mL five-neck flask, and introducing nitrogen for 0.5h at 30 ℃ under the condition of constant stirring; during the process, the pH value is continuously monitored by a pH meter and is adjusted to be neutral by 2 mol/L HCl solution; then slowly dripping 3 mL of TEOS solution with the mass fraction of 7%; continuously stirring for 10 min, adjusting the pH value to 9, and continuously stirring for 12h to finish the reaction; washing the product with deionized water for 3 times, and vacuum drying at 50 deg.C for 12h to obtain "surface coated SiO₂Fe of the layer₃O₄@SiO₂Magnetic nanoparticles ";

taking 3 parts of hydrophobic SiO₂Adding the nano particles into 200 parts of absolute ethyl alcohol, uniformly stirring for 8 min at a constant speed of 200r/min, and uniformly mixing by ultrasonic dispersion at normal temperature for 30min to obtain a fully dispersed suspension system; adding the suspension system into a 250mL three-neck flask, slowly dropwise adding 5 parts of octadecylamine, and continuously stirring for 8 hours to finish the reaction; washing the product with absolute ethyl alcohol for 3 times, and vacuum drying at 50 deg.C for 12h to obtain SiO with octadecylamine layer coated on the surface₂@ octadecylamine nanoparticles ";

taking 5 parts of the synthesized SiO with the octadecylamine layer coated on the surface₂Adding the @ octadecylamine nanoparticles into 100 parts of HCl solution with the pH value of 5, uniformly stirring at 180r/min for 8 min, ultrasonically dispersing at normal temperature for 30min, and uniformly mixing to obtain a fully dispersed suspension system 1; taking 1 part of' surface coated SiO₂Fe of the layer₃O₄@SiO₂Adding the magnetic nanoparticles into 100 parts of absolute ethyl alcohol, uniformly stirring for 8 min at a constant speed of 180r/min, ultrasonically dispersing at normal temperature for 10 min, and uniformly mixing to obtain a fully dispersed suspension system 2;

adding the suspension system 1 into a 250mL three-neck flask, uniformly stirring for 5 min at 180r/min, and then slowly dropwise adding the suspension system 2; continuously stirring for 8 min, adjusting the pH value to 4, continuously stirring for 12h, finishing the reaction, then adjusting the pH value of the system to 9, and continuously stirring for 1h until finishing the reaction; product is deionizedWashing with water for 3 times, vacuum drying at 50 deg.C for 12h to obtain Fe with double-layer coating structure with octadecylamine layer on surface₃O₄@SiO₂@ octadecylamine magnetic nanoparticles.

In the invention, the magnetic nanoparticles with pH value responsiveness are used as the reinforcing agent and are fully wrapped by the poly-alpha-olefin molecular chain to prepare the polyolefin bulk solid containing the magnetic nanoparticles to construct the composite drag reducer, and compared with the composite drag reducer constructed by taking common particles as the reinforcing agent, the composite drag reducer has the following advantages:

the composite drag reducer with the magnetic nanoparticles as the cores, which is prepared by the invention, can efficiently separate particles from drag reducer-containing oil products after the transportation is finished by constructing a high-strength magnetic field, so that the catalyst poisoning caused by the particles is avoided, and the quality of the oil products is protected; then grafting an organic amine group on the surface of the recovered magnetic nanoparticles, thereby realizing repeated reutilization;

secondly, the surface lipophilicity/hydrophilicity of the magnetic nanoparticles has the characteristic of pH value response reversible conversion, and the surfaces of the magnetic particles are lipophilicity in a neutral environment at an initial stage, so that the magnetic nanoparticles can be fully wrapped by poly-alpha-olefin molecular chains; in an acidic environment, amino on the surface of the magnetic nano particle reacts with hydrogen ions to generate-NRH⁺The hydrophilic-lipophilic balance value, namely the HLB value is increased, the surface of the magnetic particles is changed into hydrophilicity, and the high-efficiency separation of the particles and the high-molecular chain scission after shearing damage can be realized; after use, an alkaline/neutral environment was constructed, the-NRH on the surface of the magnetic nanoparticles⁺The amino group is converted, the surface of the magnetic particle is converted into lipophilicity, and the magnetic nano particle can be reused;

thirdly, through constructing magnetic nano particles and a composite drag reducer which are recovered by a high-strength magnetic field, the structure of a polymer molecular chain in the composite material is damaged through high-speed shearing, the surface of the magnetic nano particles is converted from lipophilicity into hydrophilicity through acid liquid treatment so as to realize the efficient separation of the particles and a high polymer broken chain after the shearing damage, then the recovery of the magnetic nano particles is realized through the high-strength magnetic field, the surface of the recovered nano particles is converted from hydrophilicity into lipophilicity through alkali treatment, and the pH value responsive magnetic nano particles with a double-layer coating structure which can be reused are obtained and can be used for preparing the next batch of composite drag reducer containing the magnetic nano particles.

The above description is only a few of the preferred embodiments of the present invention, and any person skilled in the art may modify the above-described embodiments or modify them into equivalent ones. Therefore, the technical solution according to the present invention is subject to corresponding simple modifications or equivalent changes, as far as the scope of the present invention is claimed.