An improved rotating microchannel(IRM) separator was further explored in the intensification for demulsification and separation process. Oil-in-water(O/W) emulsion system of 2-ethylhexyl phosphoric acid-2-ethylhexyl e...An improved rotating microchannel(IRM) separator was further explored in the intensification for demulsification and separation process. Oil-in-water(O/W) emulsion system of 2-ethylhexyl phosphoric acid-2-ethylhexyl ester(P507)–water without emulsifier was employed to evaluate the performance of the new equipment. In this experiment, the influence on demulsification separation process was explored by changing the geometrical structure and channel height of the microchannel and combining the liquid–liquid two-phase flow pattern, and the correlation general graph between demulsification efficiency and dimensionless parameters was established. The total demulsification effect of the IRM and the separation capacity of the clear organic phase recovered from demulsification are significantly improved. In addition, the liquid–liquid two-phase flow pattern of the clear organic phase after demulsification and the remaining emulsion in the IRM are observed and recorded by high-speed photography. The separation ability of organic phase from the upper outlet can be significantly improved when the total demulsification rate of IRM is up to 90%. There are 3 types and 6 kinds of flow patterns observed. The results demonstrated that the suitable demulsification performance is obtained when the liquid–liquid two-phase inside the IRM is in a parallel pattern. Finally, the relation map between total demulsification efficiency and the universal flow is drawn, which provides a basis for the accurate control of the IRM device.展开更多
As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsifica...As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsification behavior,characteristics,and stages under BPEF were explored.It was discovered that BPEF drove SSO/W emulsion to move and form vortexes,during which the oil droplets aggregated and accumulated to generate an oil droplet layer(ODL).ODL subsequently transformed into a continuous oil layer(COL)leading to the demulsification and separation of SSO/W emulsion.The conversion rate of ODL to COL was defined and used to evaluate the demulsification process and reflect the coalescence ability and transformation efficiency of dispersed oil droplets into COL.Furthermore,the effects of BPEF voltage,frequency,duty cycle,ratio of pulse output time,and surfactant type and content on the demulsification performance were examined.The optimal values of BPEF parameters for demulsification operation were 400 V,25 Hz,50%,and 4:1.O/W emulsion containing anionic surfactant was apt to be demulsified by BPEF,nonionic surfactant took the second place and cationic surfactant was the most difficult.A high surfactant content was not conducive to the BPEF demulsification.This work is anticipated to provide useful guidance for oil/water separation and oil recovery from actual emulsified oily wastewater by BPEF.展开更多
The hydrophilic porous glass membranes were used to demulsify water in oil emulsion, liquid membrane and demulsification efficiency can reach more than 96 percent. Effects of pore size of the membrane, transmembrane p...The hydrophilic porous glass membranes were used to demulsify water in oil emulsion, liquid membrane and demulsification efficiency can reach more than 96 percent. Effects of pore size of the membrane, transmembrane pressure and volumetric ratio of oil phase to internal aqueous phase in the emulsion on demulsification were investigated. Correspondingly, effect of transmembrane pressure on permeation flux of the droplets was also studied.展开更多
Magnetic particles were coupled with a flocculant to enhance the demulsification and separation of waste cutting emulsions.The optimal magnetic particle size and critical magnetic field conditions were investigated to...Magnetic particles were coupled with a flocculant to enhance the demulsification and separation of waste cutting emulsions.The optimal magnetic particle size and critical magnetic field conditions were investigated to achieve large-scale engineering application of magnetic demulsification separation for waste cutting emulsion treatment.The micro-scale magnetic particles were found to show comparable effects to nano-scale magnetic particles on enhancing the demulsification and separation of cutting emulsions,which are beneficial for broadening the selectivity of low-cost magnetic particles.The critical magnetic separation region was determined to be an area 40 mm from the magnetic field source.Compared to the flocculant demulsification,the magnetic demulsification separation exhibited a significant advantage in accelerating flocs-water separation by decreasing the separation time of flocs from 180-240 min to less than 15 min,compressing the flocs by reducing the floc volume ratio from 60%-90%to lower than 20%,and showing excellent adaptability to the variable properties of waste cutting emulsions.Coupled with the design of the magnetic disk separator,continuous demulsification separation of the waste cutting emulsion was achieved at 1.0 t/hr for at least 10 hr to obtain clear effluent with 81%chemical oxygen demand removal and 89%turbidity reduction.This study demonstrates the feasibility of applying magnetic demulsification separation to large-scale continuous treatment of waste emulsion.Moreover,it addresses the flocs-water separation problems that occur in practical flocculant demulsification engineering applications.展开更多
The crude oil recovery process is frequently associated with the formation of stable emulsions due to factors such as turbulent flow in pipelines and the presence of surface-active substances that naturally occur in c...The crude oil recovery process is frequently associated with the formation of stable emulsions due to factors such as turbulent flow in pipelines and the presence of surface-active substances that naturally occur in crude oil.These emulsions are undesirable for the petroleum industry because their destruction/treatment adds to the overall production cost and causes the loss of valuable amounts of crude oil.Therefore,it is essential,for economic and environmental reasons,to optimize the crude oil demulsification process.The effective treatment of crude oil emulsions requires understanding of the process and factors leading to their formation and stabilization.In this sense,suitable treatment methods and possible preventive measures to avoid their formation can be employed.The present study reviews recent oilfield emulsion types and the factors responsible for their formation and stabilization.The different demulsification techniques employed were then extensively examined.Demulsification tech-niques include mechanical,thermal,electrical,and chemical methods with different demulsification mechanisms affected by many factors such as emulsions type and properties,demulsifiers characteris-tics,presence of solids stabilized emulsions,etc.The demulsification efficiency depends on the operating parameters of the process,the economics involved,and the environmental impact,which are the main factors considered in selecting a suitable demulsification technique.Future research on the demulsifi-cation of crude oil emulsions should focus on real crude oil emulsions studies at a pilot scale level,the effect of aging on crude oil emulsions,the combination of multiple demulsification techniques and their synergistic effects,and the use of natural,ecofriendly demulsifiers.展开更多
A functional fabric with hierarchical structure consisting of basalt fibre fabric as a substrate and polyvinyl alcohol as a coating was developed,aiming at providing a low cost and high-performance way to separate hig...A functional fabric with hierarchical structure consisting of basalt fibre fabric as a substrate and polyvinyl alcohol as a coating was developed,aiming at providing a low cost and high-performance way to separate highly emulsified oil in water.The coating functioned as a hydrophilic gate for the penetration of water in the emulsion,whereas the micro-channels formed in the fabric offered capillary force for the continuous flow of water.The synergy of these two materials led to the increase on the oil concentration in the liquid,which in turn enhanced the collision of emulsified oil droplets to aggregate into large ones in the emulsion and resulted separation from the water.Based on these findings,an aggregation-induced demulsification process was proposed to explain the above phenomenon,and the mechanism was confirmed by studying the distribution of oil droplets in emulsion with a controlled separation degree.展开更多
Encapsulations are being increasingly investigated in both academic research and industrial manufacturing and applied in numerous fields,such as phase change materials and smart materials.In this paper,a novel strateg...Encapsulations are being increasingly investigated in both academic research and industrial manufacturing and applied in numerous fields,such as phase change materials and smart materials.In this paper,a novel strategy of demulsification-induced fast solidification(DIFS)was proposed for the rapid fabrication(within 1 s)of polymer encapsulations via immersion of demulsifier particles in emulsion.The DIFS method allowed the fabrication of three-dimensional(3D)hollow polymer encapsulations with precisely controlled size and thickness over a wide range from micron to millimeter within just 1 s.Magnetic nanoparticles and luminescent materials were further introduced into 3D hollow polymer encapsulations via facile blending method.Moreover,encapsulated paraffin phase change materials with good thermal stability were also obtained using the DIFS method.Therefore,this work provides new insights into the design and preparation of functionalized encapsulation materials.展开更多
The present work focused on the environmentally friendly deep desalination of crude oil using ethylene glycol as the extraction solvent and quartz sand as the demulsifier.The effect of droplet size distribution in the...The present work focused on the environmentally friendly deep desalination of crude oil using ethylene glycol as the extraction solvent and quartz sand as the demulsifier.The effect of droplet size distribution in the emulsion on the dehydration results and desalination efficiency was investigated.Experimental results showed that the desalination efficiencies of Sarir and Basra crude oils were 93.3%and 90.0%,respectively.Furthermore,the desalination efficiency of Basra crude oil using ethylene glycol could be enhanced up to 96.7%by adding 30 g/L quartz sand with a particle size of 15μm.Finally,94%of the ethylene glycol and 86%of the quartz sand could be recovered from the emulsion.This process offers an alternative method to the deep desalination of crude oil.展开更多
A new mechanism of electric demulsification was proposed and the coalescence behavior of fine waterdrops in oil under electric field was discussed in detail On this basis,a mathematical description for phaseseparation...A new mechanism of electric demulsification was proposed and the coalescence behavior of fine waterdrops in oil under electric field was discussed in detail On this basis,a mathematical description for phaseseparation of emulsion in electric field has been derived and proved to be in good agreement with experimentaldata.Conditions influenced the electric coalescence was examined in a batch pulsed A.C.electric demulsifier.展开更多
The rising production of produced water from oilfields had been proven to bring detrimental environmental effects.In this study,an efficient,recyclable,and environmental-friendly reduced graphene oxide immobilizedκ-C...The rising production of produced water from oilfields had been proven to bring detrimental environmental effects.In this study,an efficient,recyclable,and environmental-friendly reduced graphene oxide immobilizedκ-Carrageenan hydrogel composite(κCaGO)was fabricated as an alternative sorbent for crude oil-in-water demulsification.Polyethyleneimine(PEI)was employed to form a stable hydrogel composite.The conditions for the immobilization of graphene oxide(GO)on PEI-modifiedκ-Carrageenan(κC)beads were optimized appropriately.An immobilization yield of 77%was attained at 2%PEI,2 h immobilization activation time,and pH 6.5.Moreover,the synthesizedκCaGO is capable of demulsification with an average demulsification efficiency of 70%.It was found that the demulsification efficiency increases with salinity andκCaGO dosage,and it deteriorates under alkaline condition.These phenomena can be attributed to the interfacial interactions betweenκCaGO and the emulsion.Furthermore,theκCaGO can be recycled to use for up to six cycles without significant leaching and degradation.As such,the synthesizedκCaGO could be further developed as a potential sorbent substitute for the separation of crude oil from produced water.展开更多
As the depth and horizontal length of shale gas development wells increase,the requirement for the temperature resistance and the ability of the drilling fluids to stabilize the shale formation becomes higher.A new ty...As the depth and horizontal length of shale gas development wells increase,the requirement for the temperature resistance and the ability of the drilling fluids to stabilize the shale formation becomes higher.A new type of high temperature and high density white oil based drilling fluid system has been developed in laboratory.Research shows that the drilling fluid system has good rheological property,low filtration loss,strong anti-debris pollution capability and good plugging performance at high temperature and high density.The system has been successfully applied in the 201H7-6 well.Application results show that the drilling fluid rheology,high temperature and high pressure fluid loss and demulsification voltage meet the field requirements.The drilling fluid performance is stable in drilling an 1800 m horizontal section,and no stuck or shale swelling and wellbore collapsing are induced.It is the first well drilled successfully with domestic white oil-based drilling fluid in Zigong Region.It also sets several new records including the deepest well,the shortest drilling cycle,and the fastest drilling speed in that region,which provides valuable experience for the future drilling activities.展开更多
Stable water-in-oil emulsions are produced in oil exploitation and cause many environmental and operational issues.In this paper,a co-polymer demulsifier is reported in detail;an emulsion polymerization method is used...Stable water-in-oil emulsions are produced in oil exploitation and cause many environmental and operational issues.In this paper,a co-polymer demulsifier is reported in detail;an emulsion polymerization method is used to prepare nano-P(MMA-AA-EA)with MMA,AA and EA as the monomers,DVB as the cross-linker and APS as the initiator.The resulting products are characterized by FT-IR.Furthermore,the surface tension and particles size analysis is investigated.The results show that the surface tension reduction is 10.66 mN/m at 20?C when the concentration of co-polymer is 1000 ppm and the average size is 76.99 nm.Moreover,the HLB of polymer is discussed specifically by changing the amount of AA.With the increase of AA,the HLB value of the polymer is increased accordingly.Besides,the demulsification performance of the co-polymer is also evaluated at different synthesis and demulsification conditions.It is showed that the maximum demulsification efficiency is 96%at 70?C for 60 min.The optimum concentration of demulsifier is 400 ppm when the amounts of AA and DVB are 1.4 g and 0.1 g,respectively.At last,the process of demulsification is showed under a microscope;the coalescence process of water droplets is indicated under the action of the demulsifier.展开更多
When drilling deep wells and ultra-deep wells, the downhole high temperature and high pressure environment will affect the emulsion stability of oil-based drilling fluids. Moreover, neither the demulsification voltage...When drilling deep wells and ultra-deep wells, the downhole high temperature and high pressure environment will affect the emulsion stability of oil-based drilling fluids. Moreover, neither the demulsification voltage method nor the centrifugal method currently used to evaluate the stability of oil-based drilling fluids can reflect the emulsification stability of drilling fluids under high temperature and high pressure on site. Therefore, a high-temperature and high-pressure oil-based drilling fluid emulsion stability evaluation instrument is studied, which is mainly composed of a high-temperature autoclave body, a test electrode, a temperature control system, a pressure control system, and a test system. The stability test results of the instrument show that the instrument can achieve stable testing and the test data has high reliability. This instrument is used to analyze the factors affecting the emulsion stability of oil-based drilling fluids. The experimental results show that under the same conditions, the higher the stirring speed, the better the emulsion stability of the drilling fluid;the longer the stirring time, the better the emulsion stability of the drilling fluid;the greater the oil-water ratio, the better the emulsion stability of the drilling fluid. And the test results of the emulsification stability of oil-based drilling fluids at high temperature and high pressure show that under the same pressure, as the temperature rises, the emulsion stability of oil-based drilling fluids is significantly reduced;at the same temperature, the With the increase in pressure, the emulsion stability of oil-based drilling fluids is in a downward trend, but the decline is not large. Relatively speaking, the influence of temperature on the emulsion stability of oil-based drilling fluids is greater than that of pressure.展开更多
Electrospinning and calcination technique have been combined to fabricate N-doped carbon nanofibers(N-CNFs)by introducing amino grafted few-layered hexagonal boron nitride(amino@BN)into polyacrylonitrile(PAN)matrix as...Electrospinning and calcination technique have been combined to fabricate N-doped carbon nanofibers(N-CNFs)by introducing amino grafted few-layered hexagonal boron nitride(amino@BN)into polyacrylonitrile(PAN)matrix as filler followed by carbonization.For the high N-doping level(10.7%,atomic fraction)with the final product,the as-prepared N-CNFs exhibit interesting surface wettability(superamphiphilicity in air and underwater oleophilicity).Moreover,compared with pristine PAN derived carbon nanofibers(marked as CNFs),N-CNFs exhibit higher graphic structure under fixed carbonizing temperature as well.Taking these advantages aforementioned,the as-prepared N-CNFs exhibit good specific capacitance(ca.200.1 F/g)without activation treatment at the current density of 0.5 A/g in three-electrode configuration,which is about 149%that of CNFs(ca.134 F/g).What’s more,our N-CNFs also display the unexpected capacity to demulsify diverse surfactant free oil-in-water emulsions by simple filtration in large scale with the high water flux ca.(23578±150)L·m^(−2)·h^(−1).展开更多
Investigation of demulsification of polybutadiene latex (PBL)wastewater by polyaluminum chloride (PAC)indicated that there was an appropriate dosage range for latex removal.The demulsifieation mechanism of PAC was ads...Investigation of demulsification of polybutadiene latex (PBL)wastewater by polyaluminum chloride (PAC)indicated that there was an appropriate dosage range for latex removal.The demulsifieation mechanism of PAC was adsorption-charge neutralization and its appropriate dosage range was controlled by zeta potential.When the zeta potential of the mixture was between -15and 15mV aider adding PAC,the demulsification effect was good.Decreasing the latex concentration in chemical oxygen demand (COD)from 8.0g/L to 0.2g/L made the appropriate PAC dosage range narrower and caused the maximum latex removal efficiency to decrease from 95%to 37%.Therefore,more accurate PAC dosage control is required.Moreover,-adding 50mg/L sulfate broadened the appropriate PAC dosage range,resulting in an increase in maximum latex removal efficiency from 37%to 91%for wastewater of 0.2g COD/L.The addition of sulfate will favor more flexible PAC dosage control in demulsification of PBL wastewater.展开更多
本文利用一种新的聚苯乙烯(PS)微乳液的凝胶化现象,制备了结构稳定的PS凝胶,并通过可控的毛细收缩过程获得了具有不同孔隙结构的PS块体.对PS微乳液的凝胶化机制的系统研究表明,在PS微乳液中加入适量特定的水溶性有机溶剂后,可实现PS微...本文利用一种新的聚苯乙烯(PS)微乳液的凝胶化现象,制备了结构稳定的PS凝胶,并通过可控的毛细收缩过程获得了具有不同孔隙结构的PS块体.对PS微乳液的凝胶化机制的系统研究表明,在PS微乳液中加入适量特定的水溶性有机溶剂后,可实现PS微乳液的破乳,PS乳胶粒子周围的表面活性剂完全解吸附,并自发团聚成二次颗粒,在适当温度条件下可通过分子链缠结组装形成三维多孔凝胶.不同溶剂实现PS微乳液凝胶化的能力可以通过d2T/η参数的大小衡量和评估.通过进一步调整成胶时间与溶剂置换程度,PS凝胶可在后续的干燥过程中实现不同程度的收缩,从而得到密度范围在0.06–1.14 g cm^(-3)的多孔或致密PS块体.这种PS凝胶化策略是一种简单高效的PS成型方法,避免了成型设备、模板、成孔剂以及大量表面活性剂的应用,有望成为制备功能高分子聚合物块体材料的新方法.展开更多
The efficient and rapid separation of oil from stabilized oil-in-water emulsions with micro/nanometer size is a global challenge.Owing to the low oil content in oil-in-water emulsions,separating the oil by simply cont...The efficient and rapid separation of oil from stabilized oil-in-water emulsions with micro/nanometer size is a global challenge.Owing to the low oil content in oil-in-water emulsions,separating the oil by simply controlling the surface wettability is difficult.Controlling the pore size of the membrane surface to achieve separation will lead to a sharp decrease in flux.Herein,inspired by cell membrane transportation,a hydrophilic/hydrophobic bifunctional Janus membrane for stable oil-in-water separation was prepared by simple surface polymerization and vapor diffusion.The prepared Janus membrane contained a hydrophobic side and hydrophilic polyamine layer.When used for oil-in-water emulsion separation,the polyamine layer accumulated micro/nanometer oil droplets,forming an oil layer on the hydrophobic surface.Water was retained by the 1H,1H,2H,2H-perfluorooctyl trichlorosilane layer,allowing oil droplets to selectively permeate through the membrane,achieving the separation effect.As the pore size of the modified fabric was basically unchanged,the permeation flux was fast(1.53×10^(3) Lm^(−2) h^(−1)).Furthermore,the poly(N,N-dimethylaminoethyl methacrylate)layer destroyed the emulsion stability,making the emulsion droplets aggregate without affecting the separation efficiency with fast permeation flux.Therefore,the prepared bifunctional Janus membrane shows great potential for actual wastewater treatment.展开更多
文摘An improved rotating microchannel(IRM) separator was further explored in the intensification for demulsification and separation process. Oil-in-water(O/W) emulsion system of 2-ethylhexyl phosphoric acid-2-ethylhexyl ester(P507)–water without emulsifier was employed to evaluate the performance of the new equipment. In this experiment, the influence on demulsification separation process was explored by changing the geometrical structure and channel height of the microchannel and combining the liquid–liquid two-phase flow pattern, and the correlation general graph between demulsification efficiency and dimensionless parameters was established. The total demulsification effect of the IRM and the separation capacity of the clear organic phase recovered from demulsification are significantly improved. In addition, the liquid–liquid two-phase flow pattern of the clear organic phase after demulsification and the remaining emulsion in the IRM are observed and recorded by high-speed photography. The separation ability of organic phase from the upper outlet can be significantly improved when the total demulsification rate of IRM is up to 90%. There are 3 types and 6 kinds of flow patterns observed. The results demonstrated that the suitable demulsification performance is obtained when the liquid–liquid two-phase inside the IRM is in a parallel pattern. Finally, the relation map between total demulsification efficiency and the universal flow is drawn, which provides a basis for the accurate control of the IRM device.
基金Scientific Platform Project of the Ministry of Education(fykf201907)the Postdoctoral Science Foundation Project of the Natural Science Foundation of Chongqing Municipality(cstc2021jcyjbshX0194)+3 种基金Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202100820 and KJZD-K201900804)Science and Technology Innovation Project of the Construction of the Chengdu-Chongqing Economic Circle of Chongqing Municipal Education Commission(KJCX2020036)Scientific Research Project of Chongqing Technology and Business University(2152016 and 2056006)Chongqing Technical Innovation and Application Project(cstc2019jscx-msxmX0275).
文摘As a novel electric demulsification method,bidirectional pulsed electric field(BPEF)was employed to demulsify the surfactant stabilized oil-in-water(SSO/W)emulsion for oil/water separation in this work.The demulsification behavior,characteristics,and stages under BPEF were explored.It was discovered that BPEF drove SSO/W emulsion to move and form vortexes,during which the oil droplets aggregated and accumulated to generate an oil droplet layer(ODL).ODL subsequently transformed into a continuous oil layer(COL)leading to the demulsification and separation of SSO/W emulsion.The conversion rate of ODL to COL was defined and used to evaluate the demulsification process and reflect the coalescence ability and transformation efficiency of dispersed oil droplets into COL.Furthermore,the effects of BPEF voltage,frequency,duty cycle,ratio of pulse output time,and surfactant type and content on the demulsification performance were examined.The optimal values of BPEF parameters for demulsification operation were 400 V,25 Hz,50%,and 4:1.O/W emulsion containing anionic surfactant was apt to be demulsified by BPEF,nonionic surfactant took the second place and cationic surfactant was the most difficult.A high surfactant content was not conducive to the BPEF demulsification.This work is anticipated to provide useful guidance for oil/water separation and oil recovery from actual emulsified oily wastewater by BPEF.
文摘The hydrophilic porous glass membranes were used to demulsify water in oil emulsion, liquid membrane and demulsification efficiency can reach more than 96 percent. Effects of pore size of the membrane, transmembrane pressure and volumetric ratio of oil phase to internal aqueous phase in the emulsion on demulsification were investigated. Correspondingly, effect of transmembrane pressure on permeation flux of the droplets was also studied.
基金supported by the National Natural Science Foundation of China(No.51978490)Natural Science Foun-dation of Shanghai(No.20ZDR1461200)the Major Sci-ence and Technology Program for Water Pollution Control and Treatment,China(No.2017ZX07202003-02).
文摘Magnetic particles were coupled with a flocculant to enhance the demulsification and separation of waste cutting emulsions.The optimal magnetic particle size and critical magnetic field conditions were investigated to achieve large-scale engineering application of magnetic demulsification separation for waste cutting emulsion treatment.The micro-scale magnetic particles were found to show comparable effects to nano-scale magnetic particles on enhancing the demulsification and separation of cutting emulsions,which are beneficial for broadening the selectivity of low-cost magnetic particles.The critical magnetic separation region was determined to be an area 40 mm from the magnetic field source.Compared to the flocculant demulsification,the magnetic demulsification separation exhibited a significant advantage in accelerating flocs-water separation by decreasing the separation time of flocs from 180-240 min to less than 15 min,compressing the flocs by reducing the floc volume ratio from 60%-90%to lower than 20%,and showing excellent adaptability to the variable properties of waste cutting emulsions.Coupled with the design of the magnetic disk separator,continuous demulsification separation of the waste cutting emulsion was achieved at 1.0 t/hr for at least 10 hr to obtain clear effluent with 81%chemical oxygen demand removal and 89%turbidity reduction.This study demonstrates the feasibility of applying magnetic demulsification separation to large-scale continuous treatment of waste emulsion.Moreover,it addresses the flocs-water separation problems that occur in practical flocculant demulsification engineering applications.
文摘The crude oil recovery process is frequently associated with the formation of stable emulsions due to factors such as turbulent flow in pipelines and the presence of surface-active substances that naturally occur in crude oil.These emulsions are undesirable for the petroleum industry because their destruction/treatment adds to the overall production cost and causes the loss of valuable amounts of crude oil.Therefore,it is essential,for economic and environmental reasons,to optimize the crude oil demulsification process.The effective treatment of crude oil emulsions requires understanding of the process and factors leading to their formation and stabilization.In this sense,suitable treatment methods and possible preventive measures to avoid their formation can be employed.The present study reviews recent oilfield emulsion types and the factors responsible for their formation and stabilization.The different demulsification techniques employed were then extensively examined.Demulsification tech-niques include mechanical,thermal,electrical,and chemical methods with different demulsification mechanisms affected by many factors such as emulsions type and properties,demulsifiers characteris-tics,presence of solids stabilized emulsions,etc.The demulsification efficiency depends on the operating parameters of the process,the economics involved,and the environmental impact,which are the main factors considered in selecting a suitable demulsification technique.Future research on the demulsifi-cation of crude oil emulsions should focus on real crude oil emulsions studies at a pilot scale level,the effect of aging on crude oil emulsions,the combination of multiple demulsification techniques and their synergistic effects,and the use of natural,ecofriendly demulsifiers.
基金Western Light Foundation of Chinese Academy of Sciences,Grant/Award Numbers:2019-XBQNXZB-010,2019-JCTD-001Poverty Alleviation Program of CAS,Grant/Award Number:KFJ-FP-202103Program forAttracting High-Level Talents in Xingjiang Uyghur Autonomous Region。
文摘A functional fabric with hierarchical structure consisting of basalt fibre fabric as a substrate and polyvinyl alcohol as a coating was developed,aiming at providing a low cost and high-performance way to separate highly emulsified oil in water.The coating functioned as a hydrophilic gate for the penetration of water in the emulsion,whereas the micro-channels formed in the fabric offered capillary force for the continuous flow of water.The synergy of these two materials led to the increase on the oil concentration in the liquid,which in turn enhanced the collision of emulsified oil droplets to aggregate into large ones in the emulsion and resulted separation from the water.Based on these findings,an aggregation-induced demulsification process was proposed to explain the above phenomenon,and the mechanism was confirmed by studying the distribution of oil droplets in emulsion with a controlled separation degree.
基金Supported by the National Natural Science Foundation of China(No.21504008).
文摘Encapsulations are being increasingly investigated in both academic research and industrial manufacturing and applied in numerous fields,such as phase change materials and smart materials.In this paper,a novel strategy of demulsification-induced fast solidification(DIFS)was proposed for the rapid fabrication(within 1 s)of polymer encapsulations via immersion of demulsifier particles in emulsion.The DIFS method allowed the fabrication of three-dimensional(3D)hollow polymer encapsulations with precisely controlled size and thickness over a wide range from micron to millimeter within just 1 s.Magnetic nanoparticles and luminescent materials were further introduced into 3D hollow polymer encapsulations via facile blending method.Moreover,encapsulated paraffin phase change materials with good thermal stability were also obtained using the DIFS method.Therefore,this work provides new insights into the design and preparation of functionalized encapsulation materials.
基金financially supported by the National Natural Science Foundation of China(51773012)Fundamental Research Funds for the Central Universities(buctrc202135)China Scholarship Council Program(201906880031).
文摘The present work focused on the environmentally friendly deep desalination of crude oil using ethylene glycol as the extraction solvent and quartz sand as the demulsifier.The effect of droplet size distribution in the emulsion on the dehydration results and desalination efficiency was investigated.Experimental results showed that the desalination efficiencies of Sarir and Basra crude oils were 93.3%and 90.0%,respectively.Furthermore,the desalination efficiency of Basra crude oil using ethylene glycol could be enhanced up to 96.7%by adding 30 g/L quartz sand with a particle size of 15μm.Finally,94%of the ethylene glycol and 86%of the quartz sand could be recovered from the emulsion.This process offers an alternative method to the deep desalination of crude oil.
文摘A new mechanism of electric demulsification was proposed and the coalescence behavior of fine waterdrops in oil under electric field was discussed in detail On this basis,a mathematical description for phaseseparation of emulsion in electric field has been derived and proved to be in good agreement with experimentaldata.Conditions influenced the electric coalescence was examined in a batch pulsed A.C.electric demulsifier.
基金The authors would like to acknowledge for the financial supports given by Fundamental Research Grant Scheme (FRGS/1/2019/TK02/CURTIN/03/2) from Ministry of Higher Education (MOHE),Malaysia.
文摘The rising production of produced water from oilfields had been proven to bring detrimental environmental effects.In this study,an efficient,recyclable,and environmental-friendly reduced graphene oxide immobilizedκ-Carrageenan hydrogel composite(κCaGO)was fabricated as an alternative sorbent for crude oil-in-water demulsification.Polyethyleneimine(PEI)was employed to form a stable hydrogel composite.The conditions for the immobilization of graphene oxide(GO)on PEI-modifiedκ-Carrageenan(κC)beads were optimized appropriately.An immobilization yield of 77%was attained at 2%PEI,2 h immobilization activation time,and pH 6.5.Moreover,the synthesizedκCaGO is capable of demulsification with an average demulsification efficiency of 70%.It was found that the demulsification efficiency increases with salinity andκCaGO dosage,and it deteriorates under alkaline condition.These phenomena can be attributed to the interfacial interactions betweenκCaGO and the emulsion.Furthermore,theκCaGO can be recycled to use for up to six cycles without significant leaching and degradation.As such,the synthesizedκCaGO could be further developed as a potential sorbent substitute for the separation of crude oil from produced water.
文摘As the depth and horizontal length of shale gas development wells increase,the requirement for the temperature resistance and the ability of the drilling fluids to stabilize the shale formation becomes higher.A new type of high temperature and high density white oil based drilling fluid system has been developed in laboratory.Research shows that the drilling fluid system has good rheological property,low filtration loss,strong anti-debris pollution capability and good plugging performance at high temperature and high density.The system has been successfully applied in the 201H7-6 well.Application results show that the drilling fluid rheology,high temperature and high pressure fluid loss and demulsification voltage meet the field requirements.The drilling fluid performance is stable in drilling an 1800 m horizontal section,and no stuck or shale swelling and wellbore collapsing are induced.It is the first well drilled successfully with domestic white oil-based drilling fluid in Zigong Region.It also sets several new records including the deepest well,the shortest drilling cycle,and the fastest drilling speed in that region,which provides valuable experience for the future drilling activities.
基金the Open Project Program of State Key Laboratory of Petroleum Pollution Control(Grant No.PPC2016006)CNPC Research Institute of Safety and Environmental Technology.
文摘Stable water-in-oil emulsions are produced in oil exploitation and cause many environmental and operational issues.In this paper,a co-polymer demulsifier is reported in detail;an emulsion polymerization method is used to prepare nano-P(MMA-AA-EA)with MMA,AA and EA as the monomers,DVB as the cross-linker and APS as the initiator.The resulting products are characterized by FT-IR.Furthermore,the surface tension and particles size analysis is investigated.The results show that the surface tension reduction is 10.66 mN/m at 20?C when the concentration of co-polymer is 1000 ppm and the average size is 76.99 nm.Moreover,the HLB of polymer is discussed specifically by changing the amount of AA.With the increase of AA,the HLB value of the polymer is increased accordingly.Besides,the demulsification performance of the co-polymer is also evaluated at different synthesis and demulsification conditions.It is showed that the maximum demulsification efficiency is 96%at 70?C for 60 min.The optimum concentration of demulsifier is 400 ppm when the amounts of AA and DVB are 1.4 g and 0.1 g,respectively.At last,the process of demulsification is showed under a microscope;the coalescence process of water droplets is indicated under the action of the demulsifier.
文摘When drilling deep wells and ultra-deep wells, the downhole high temperature and high pressure environment will affect the emulsion stability of oil-based drilling fluids. Moreover, neither the demulsification voltage method nor the centrifugal method currently used to evaluate the stability of oil-based drilling fluids can reflect the emulsification stability of drilling fluids under high temperature and high pressure on site. Therefore, a high-temperature and high-pressure oil-based drilling fluid emulsion stability evaluation instrument is studied, which is mainly composed of a high-temperature autoclave body, a test electrode, a temperature control system, a pressure control system, and a test system. The stability test results of the instrument show that the instrument can achieve stable testing and the test data has high reliability. This instrument is used to analyze the factors affecting the emulsion stability of oil-based drilling fluids. The experimental results show that under the same conditions, the higher the stirring speed, the better the emulsion stability of the drilling fluid;the longer the stirring time, the better the emulsion stability of the drilling fluid;the greater the oil-water ratio, the better the emulsion stability of the drilling fluid. And the test results of the emulsification stability of oil-based drilling fluids at high temperature and high pressure show that under the same pressure, as the temperature rises, the emulsion stability of oil-based drilling fluids is significantly reduced;at the same temperature, the With the increase in pressure, the emulsion stability of oil-based drilling fluids is in a downward trend, but the decline is not large. Relatively speaking, the influence of temperature on the emulsion stability of oil-based drilling fluids is greater than that of pressure.
基金This work is supported by the National Natural Science Foundation of China(No.52073238)the Open Funds of the State Key Laboratory of Oil and Gas Reservoir Geology and Exploration of Southwest Petroleum University,China(Nos.PLN2018-06,PLN2020-19)the Fund of the Sichuan Provincial University Key Laboratory of Oil and Gas Field Materials,China(Nos.X151518KCL04,X151518KCL07).
文摘Electrospinning and calcination technique have been combined to fabricate N-doped carbon nanofibers(N-CNFs)by introducing amino grafted few-layered hexagonal boron nitride(amino@BN)into polyacrylonitrile(PAN)matrix as filler followed by carbonization.For the high N-doping level(10.7%,atomic fraction)with the final product,the as-prepared N-CNFs exhibit interesting surface wettability(superamphiphilicity in air and underwater oleophilicity).Moreover,compared with pristine PAN derived carbon nanofibers(marked as CNFs),N-CNFs exhibit higher graphic structure under fixed carbonizing temperature as well.Taking these advantages aforementioned,the as-prepared N-CNFs exhibit good specific capacitance(ca.200.1 F/g)without activation treatment at the current density of 0.5 A/g in three-electrode configuration,which is about 149%that of CNFs(ca.134 F/g).What’s more,our N-CNFs also display the unexpected capacity to demulsify diverse surfactant free oil-in-water emulsions by simple filtration in large scale with the high water flux ca.(23578±150)L·m^(−2)·h^(−1).
基金the China Special S&T Project on Treatment And Control of Water Pollution (No.2012ZX07201-005)the National Natural Science Foundation of China (Grant No. 51308521).
文摘Investigation of demulsification of polybutadiene latex (PBL)wastewater by polyaluminum chloride (PAC)indicated that there was an appropriate dosage range for latex removal.The demulsifieation mechanism of PAC was adsorption-charge neutralization and its appropriate dosage range was controlled by zeta potential.When the zeta potential of the mixture was between -15and 15mV aider adding PAC,the demulsification effect was good.Decreasing the latex concentration in chemical oxygen demand (COD)from 8.0g/L to 0.2g/L made the appropriate PAC dosage range narrower and caused the maximum latex removal efficiency to decrease from 95%to 37%.Therefore,more accurate PAC dosage control is required.Moreover,-adding 50mg/L sulfate broadened the appropriate PAC dosage range,resulting in an increase in maximum latex removal efficiency from 37%to 91%for wastewater of 0.2g COD/L.The addition of sulfate will favor more flexible PAC dosage control in demulsification of PBL wastewater.
基金financially supported by the National Science Fund for Distinguished Young Scholars of China(51525204)the National Natural Science Foundation of China(51702229)。
文摘本文利用一种新的聚苯乙烯(PS)微乳液的凝胶化现象,制备了结构稳定的PS凝胶,并通过可控的毛细收缩过程获得了具有不同孔隙结构的PS块体.对PS微乳液的凝胶化机制的系统研究表明,在PS微乳液中加入适量特定的水溶性有机溶剂后,可实现PS微乳液的破乳,PS乳胶粒子周围的表面活性剂完全解吸附,并自发团聚成二次颗粒,在适当温度条件下可通过分子链缠结组装形成三维多孔凝胶.不同溶剂实现PS微乳液凝胶化的能力可以通过d2T/η参数的大小衡量和评估.通过进一步调整成胶时间与溶剂置换程度,PS凝胶可在后续的干燥过程中实现不同程度的收缩,从而得到密度范围在0.06–1.14 g cm^(-3)的多孔或致密PS块体.这种PS凝胶化策略是一种简单高效的PS成型方法,避免了成型设备、模板、成孔剂以及大量表面活性剂的应用,有望成为制备功能高分子聚合物块体材料的新方法.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFC1808401)the National Natural Science Foundation of China(Grant Nos.22078213,21938006,51973148,21776190)+1 种基金the Cutting-edge Technology Basic Research Project of Jiangsu(Grant No.BK20202012)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The efficient and rapid separation of oil from stabilized oil-in-water emulsions with micro/nanometer size is a global challenge.Owing to the low oil content in oil-in-water emulsions,separating the oil by simply controlling the surface wettability is difficult.Controlling the pore size of the membrane surface to achieve separation will lead to a sharp decrease in flux.Herein,inspired by cell membrane transportation,a hydrophilic/hydrophobic bifunctional Janus membrane for stable oil-in-water separation was prepared by simple surface polymerization and vapor diffusion.The prepared Janus membrane contained a hydrophobic side and hydrophilic polyamine layer.When used for oil-in-water emulsion separation,the polyamine layer accumulated micro/nanometer oil droplets,forming an oil layer on the hydrophobic surface.Water was retained by the 1H,1H,2H,2H-perfluorooctyl trichlorosilane layer,allowing oil droplets to selectively permeate through the membrane,achieving the separation effect.As the pore size of the modified fabric was basically unchanged,the permeation flux was fast(1.53×10^(3) Lm^(−2) h^(−1)).Furthermore,the poly(N,N-dimethylaminoethyl methacrylate)layer destroyed the emulsion stability,making the emulsion droplets aggregate without affecting the separation efficiency with fast permeation flux.Therefore,the prepared bifunctional Janus membrane shows great potential for actual wastewater treatment.
