Electric treatment is a promising method to improve the cold flowability of waxy crude oil by taking advantage of the electrorheological(ER)effect of the crude oil.However,the efficacy of viscosity reduction under an ...Electric treatment is a promising method to improve the cold flowability of waxy crude oil by taking advantage of the electrorheological(ER)effect of the crude oil.However,the efficacy of viscosity reduction under an electric field differs significantly among various crude oils.This paper investigates the role of graphene nanoparticles(GNPs)in enhancing the ER effect of a waxy crude oil with less sensitivity to the electric field.It is found that the addition of GNPs may significantly enhance the ER effect and its durability.Quantitative results revealed that with 200 ppm GNPs,the maximum viscosity reduction reaches 78.4%(vs.57.1%for undoped oil)at 34℃,and the treatment time to achieve 57.1%viscosity reduction is shortened from 10 min to 2 min.Furthermore,GNPs reduce the energy density threshold for maximum viscosity reduction from 1.08 J/mL to 0.96 J/mL,weaken the structure of the gelled oil(yield stress reduction:80.1%vs.43.5%for undoped oil),and extend the durability of viscosity reduction from 5 to 12 h.It is further demonstrated that both the added GNPs and charged particles in crude oil accumulate on the surfaces of wax particles under an electric field,and the effect of GNPs’nano-templating and the electrostatic repulsion of charged particles work together,weakening the wax particle interactions and thereby enhancing the ER effect.The study provides an approach to the enhancement of the cold flowability improvement efficacy by electric treatment for waxy crude oil.展开更多
Exposing waxy oils to an electric field may significantly improve their cold flowability.Our previous study has shown that interfacial polarization,i.e.,charged particle accumulation on the wax particle surface,is the...Exposing waxy oils to an electric field may significantly improve their cold flowability.Our previous study has shown that interfacial polarization,i.e.,charged particle accumulation on the wax particle surface,is the primary mechanism of the electrorheological behavior of waxy oils.However,the way that charged particles interact with wax particles under an electric field remains unknown.In this study,we found no viscosity and impedance change for two waxy crude oils after their exposure to a high-voltage electric field.However,the yield stresses were reduced obviously.We thus proposed that the collision of colloidal particles such as resins and asphaltenes with the wax particles could be an essential mechanism that the wax particle structure was weakened.To verify this hypothesis,a series of ad hoc experiments were carried out,i.e.,by performing electrorheological tests on model waxy oils containing additives removable under an electric field,including electrically-neutral colloidal particles(Fe3O4),charged colloidal particles(resins),and oil-soluble electrolyte(C22H14CoO4),respectively,and demonstrated that upon application of a high-voltage electric field,charged particles in a waxy oil may move and thus collide with wax particles,and consequently adhere to the wax particle surface.The particle collision results in damage to the wax particle network,and the electrostatic repulsion arising from the adhesion of the charged particle on the wax particle diminishes attraction between wax particles.This study clarifies the process of interfacial polarization.展开更多
According to the results of experiments and theoretical analysis, a phenomenon called ＂capture effect＂ is put forward, which could be used to describe the particles dynamic behavior of electrorheological （ER） susp...According to the results of experiments and theoretical analysis, a phenomenon called ＂capture effect＂ is put forward, which could be used to describe the particles dynamic behavior of electrorheological （ER） suspensions. Then a ＂structure-force＂ mathematical model is established to explain this effect based on electrostatic energy density equation. The analysis results show that the dynamic coupling process of ER suspensions under an external electric filed is the function not only of the electric intensity, but also of the dielectric properties and the structure form.展开更多
To investigate the influence of surface characteristics of particles on electrorheological (ER) fluids, water free complex strontium titanate particles were synthesized through the sol gel technique and different ma...To investigate the influence of surface characteristics of particles on electrorheological (ER) fluids, water free complex strontium titanate particles were synthesized through the sol gel technique and different mass fraction of the surfactant was doped in particles and dispersed in silicon oil. The test shows that surface characteristics of particles have great influence on the behavior of ER fluids. Surface tension, surface polarity and interfacial polarization are strongly related to the surface status of the dispersed particles.展开更多
PMMA wrapped alumina siloxane gel was obtained by using poly (methyl methacrylate) (PMMA) to wrap alumina siloxane sol which was made from water glass, aluminum nitrate and α methacrylic acid. Meanwhile, rare eart...PMMA wrapped alumina siloxane gel was obtained by using poly (methyl methacrylate) (PMMA) to wrap alumina siloxane sol which was made from water glass, aluminum nitrate and α methacrylic acid. Meanwhile, rare earth ions were used to dope in the course of reaction, and stable suspensions was produced by putting PMMA wrapped microcapsule powder doped with rare earths into methy silicon oil. It is found that its electrorheological (ER) effect improves strikingly after loading electric field. At a certain concentration, the immediate viscosity increases from 95 to 178 Pa·s compared to the system without doping.展开更多
Coated-PMMA microspheres consisting of poly （methyl methacrylate）（PMMA） core and barium titanate （BaTiO3） shell were synthesized by the modified sol-gel processing and then adopted as an electrorheological （ER...Coated-PMMA microspheres consisting of poly （methyl methacrylate）（PMMA） core and barium titanate （BaTiO3） shell were synthesized by the modified sol-gel processing and then adopted as an electrorheological （ER） materials. The structure and morphology of coated powders were chyfecterized by SEM and FT-IR; the shear stress of the suspensions of coated-PMMA particles and pure PMMA particles in silicone oil with a 20 vol% were investigated. The results show that the BaTiO3 coated PMMA microspheres based suspension in silicone oil exhibited typical ER behavior and stronger ER effects.展开更多
By utilizing the electrorheological effect, three-dimensional colloidal crystals can be produced, whose lattice structure can be changed from the body-centered-tetragonal lattice to other lattices under the applicatio...By utilizing the electrorheological effect, three-dimensional colloidal crystals can be produced, whose lattice structure can be changed from the body-centered-tetragonal lattice to other lattices under the application of electric fields. This paper calculates photonic band structures of such crystals with lattice structure transformation, and demonstrates the existence of complete band gaps for some intermediate lattices. Thus, it becomes possible to use the electrorheological effect to achieve photonic crystals with desired photonic gap properties resulting from tunable structures.展开更多
基金National Natural Science Foundation of China(No.52174066)the Postdoctoral Fellowship Program of CPSF(No.GZC20242006)the Science Foundation of China University of Petroleum,Beijing(No.2462024XKBH008)for providing financial support.
文摘Electric treatment is a promising method to improve the cold flowability of waxy crude oil by taking advantage of the electrorheological(ER)effect of the crude oil.However,the efficacy of viscosity reduction under an electric field differs significantly among various crude oils.This paper investigates the role of graphene nanoparticles(GNPs)in enhancing the ER effect of a waxy crude oil with less sensitivity to the electric field.It is found that the addition of GNPs may significantly enhance the ER effect and its durability.Quantitative results revealed that with 200 ppm GNPs,the maximum viscosity reduction reaches 78.4%(vs.57.1%for undoped oil)at 34℃,and the treatment time to achieve 57.1%viscosity reduction is shortened from 10 min to 2 min.Furthermore,GNPs reduce the energy density threshold for maximum viscosity reduction from 1.08 J/mL to 0.96 J/mL,weaken the structure of the gelled oil(yield stress reduction:80.1%vs.43.5%for undoped oil),and extend the durability of viscosity reduction from 5 to 12 h.It is further demonstrated that both the added GNPs and charged particles in crude oil accumulate on the surfaces of wax particles under an electric field,and the effect of GNPs’nano-templating and the electrostatic repulsion of charged particles work together,weakening the wax particle interactions and thereby enhancing the ER effect.The study provides an approach to the enhancement of the cold flowability improvement efficacy by electric treatment for waxy crude oil.
基金financial support from the National Natural Science Foundation of China(No.52174066,No.51534007).
文摘Exposing waxy oils to an electric field may significantly improve their cold flowability.Our previous study has shown that interfacial polarization,i.e.,charged particle accumulation on the wax particle surface,is the primary mechanism of the electrorheological behavior of waxy oils.However,the way that charged particles interact with wax particles under an electric field remains unknown.In this study,we found no viscosity and impedance change for two waxy crude oils after their exposure to a high-voltage electric field.However,the yield stresses were reduced obviously.We thus proposed that the collision of colloidal particles such as resins and asphaltenes with the wax particles could be an essential mechanism that the wax particle structure was weakened.To verify this hypothesis,a series of ad hoc experiments were carried out,i.e.,by performing electrorheological tests on model waxy oils containing additives removable under an electric field,including electrically-neutral colloidal particles(Fe3O4),charged colloidal particles(resins),and oil-soluble electrolyte(C22H14CoO4),respectively,and demonstrated that upon application of a high-voltage electric field,charged particles in a waxy oil may move and thus collide with wax particles,and consequently adhere to the wax particle surface.The particle collision results in damage to the wax particle network,and the electrostatic repulsion arising from the adhesion of the charged particle on the wax particle diminishes attraction between wax particles.This study clarifies the process of interfacial polarization.
文摘According to the results of experiments and theoretical analysis, a phenomenon called ＂capture effect＂ is put forward, which could be used to describe the particles dynamic behavior of electrorheological （ER） suspensions. Then a ＂structure-force＂ mathematical model is established to explain this effect based on electrostatic energy density equation. The analysis results show that the dynamic coupling process of ER suspensions under an external electric filed is the function not only of the electric intensity, but also of the dielectric properties and the structure form.
文摘To investigate the influence of surface characteristics of particles on electrorheological (ER) fluids, water free complex strontium titanate particles were synthesized through the sol gel technique and different mass fraction of the surfactant was doped in particles and dispersed in silicon oil. The test shows that surface characteristics of particles have great influence on the behavior of ER fluids. Surface tension, surface polarity and interfacial polarization are strongly related to the surface status of the dispersed particles.
文摘PMMA wrapped alumina siloxane gel was obtained by using poly (methyl methacrylate) (PMMA) to wrap alumina siloxane sol which was made from water glass, aluminum nitrate and α methacrylic acid. Meanwhile, rare earth ions were used to dope in the course of reaction, and stable suspensions was produced by putting PMMA wrapped microcapsule powder doped with rare earths into methy silicon oil. It is found that its electrorheological (ER) effect improves strikingly after loading electric field. At a certain concentration, the immediate viscosity increases from 95 to 178 Pa·s compared to the system without doping.
基金Funded by the National Natural Science Foundation of China (Nos. 10418014 and 10474074).
文摘Coated-PMMA microspheres consisting of poly （methyl methacrylate）（PMMA） core and barium titanate （BaTiO3） shell were synthesized by the modified sol-gel processing and then adopted as an electrorheological （ER） materials. The structure and morphology of coated powders were chyfecterized by SEM and FT-IR; the shear stress of the suspensions of coated-PMMA particles and pure PMMA particles in silicone oil with a 20 vol% were investigated. The results show that the BaTiO3 coated PMMA microspheres based suspension in silicone oil exhibited typical ER behavior and stronger ER effects.
基金supported by the National Key Basic Research Special Fund (Grant No. 2006CB921706)the National Natural Science Foundation of China (Grant Nos. 10604014 and 10874025)
文摘By utilizing the electrorheological effect, three-dimensional colloidal crystals can be produced, whose lattice structure can be changed from the body-centered-tetragonal lattice to other lattices under the application of electric fields. This paper calculates photonic band structures of such crystals with lattice structure transformation, and demonstrates the existence of complete band gaps for some intermediate lattices. Thus, it becomes possible to use the electrorheological effect to achieve photonic crystals with desired photonic gap properties resulting from tunable structures.
