MPEG grafted quaternized carboxymethyl chitosan for demulsification of crude oil emulsions

Four novel environmentally friendly and highly branched crude oil demulsifiers were prepared by using different molecular weight (M_n = 350, 750, 1000, 1900 g/mol) of methoxy poly(ethylene glycol) to modify quaternized N,O‐carboxymethyl chitosan. Fourier transform infrared and ¹H‐nuclear magnetic resonance were employed to confirm the structure of the demulsifiers. The surface tension of demulsifies was determined and hydrophile–lipophile balance value was calculated at the critical micelle concentration. The demulsification performance was evaluated by the bottle test method against water‐in‐oil emulsions simulated in the laboratory and it was found that the dehydration rate of four demulsifiers can come to 74.2%–80.4%, which have better demulsification performance than the commercial demulsifier JL‐1. Demulsification mechanism was discussed, and it was encouraging to find that the tiny water droplets in the emulsion coalesced to form the water phase and separated with the water from the polarization microscope. Results show that methoxy poly(ethylene glycol) grafted quaternized carboxymethyl chitosan has a promising application as a demulsifiers for dealing with W/O crude oil emulsions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45867.     

Poly(amidoamine) dendritic structures,bearing different end groups,as adhesion promoters for urea–formaldehyde wood adhesive system

A series of core‐shell poly(amidoamine) (PAMAM) dendritic compounds bearing different end groups such as  OH, NH₂, and NH₃⁺⁻Cl up to the third generation were prepared via successive Michael addition of a nucleophilic core (ethylenediamine) to methylacrylate followed by amination steps using ethylenediamine for the amine‐terminated while ethanolamine for the hydroxyl‐terminated compounds, also the protonated ammonium salt terminated form was obtained by cationization of the amine‐terminated form using hydrochloric acid solution. The Surface activity and aggregation behavior of the corresponding aqueous solutions of the prepared generations with their different end groups were studied and confirmed by surface tension measurements using ring method technique. The prepared dendrimers showed high surface activity and the measurements revealed their ability to self aggregate in water at very low concentrations, critical aggregation concentrations (CACs). The CACs were found to decrease with increasing the generation number, which implies that molecular weight and structure play important rules in controlling the surface activity and CAC. The dendritic compounds proved to be effective as adhesion promoters for urea formaldehyde (UF) resins when applied as wood adhesive systems, which was ascribed in partial to the improved wetting over the substrate, a role that is fundamentally related to the huge number of function groups present at the interface. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Study on Demulsification of Crude Oil Emulsions by Microwave Chemical Method

Abstract

The demulsifying and separating experiments of crude oil emulsion were performed by using the heating method, the thermal chemical method, the microwave radiating method, and the microwave chemical method separately. The water content of this emulsion was 78 v/v%, and the type was water‐in‐oil (w/o). The influence tendencies of the key factors on demulsification effect were explored by changing the heating temperature, the demulsifier amount used and the microwave radiating time in this paper. With the microwave chemical experiments on the self‐made emulsions of different water content, the demulsification rate and separation efficiency were explored. The type of these emulsions were oil‐in‐water (o/w), water‐in‐oil (w/o) and the multiple type, related to the water content scopes which were less than 30 v/v%, more than 70 v/v% and between them, respectively. The separation effect by the microwave chemical method for the high water content crude oil emulsion was better than that of emulsion with lower water content. For the crude oil used in this experiment, the result could be obtained that the separation efficiency was about 95 v/v% under the conditions of 50 ppm of demulsifier, 10 seconds radiation time, and 1 minute settling time for the microwave chemical method.     

A Star-Shaped Anionic Surfactant: Synthesis,Alkalinity Resistance,Interfacial Tension and Emulsification Properties at the Crude Oil–Water Interface

In this research, a star‐shaped surfactant was synthesized through the chlorination reaction, alkylation reaction and sulfonation reaction of triethanolamine, which is composed of three hydrophobic chains and three sulfonate hydrophilic groups. The critical micelle concentration (CMC) of the surfactant was measured by the surface tension method, and the results showed that it had high surface activity with CMC of 5.53 × 10^?5 mol/L. The surfactant was superior in surface active properties to the reference surfactants SDBS and DADS‐C₁₂. The interfacial tension (IFT) of the studied crude oil–water system (surfactant concentration 0.1 g/L, NaOH concentration 0.5 g/L, and experimental temperature 50 °C) dropped to 1.1 × 10^?4 mN/m, which can fulfil the requirement of surfactants for oil displacement. An aqueous solution of the surfactant and crude oil was emulsified by shaking, which formed a highly stable oil‐in‐water (O/W) emulsion with particle size of 5–20 μm. The oil displacement effect was almost 12%.     

Evaluation of nanoemulsions based on silicone polyethers for demulsification of asphaltene model emulsions

Asphaltenes are considered the main agents responsible for stabilizing petroleum emulsions. However, due to the complex chemical nature of crude oil, it is necessary to extract these molecules and prepare model solutions to investigate the effects of the various asphaltenes separately. In this study, the demulsification efficiency of oil‐in‐water (O/W) nanoemulsions based on silicone polyethers was evaluated using asphaltene model emulsions. The interfacial properties of the model emulsions were evaluated, with and without the presence of the nanoemulsions, by interfacial tension and inerfacial rheology measurements and correlating them with the ability and/or speed of diffusion to the interface. Dispersion/flocculation tests of the asphaltenes were performed to assess whether the nanoemulsions were modifying the aggregation state of the asphaltenes during the process of destabilizing the model emulsions. Through the interfacial rheology tests of the model asphaltene/saltwater system, with or without addition of the systems used in the demulsification tests, it was possible to determine the influence of the nanoemulsions on the mechanical properties of the interfacial film. The results of the water/oil gravitational separation tests showed that the nanoemulsions had separation efficiency between 80 and 95%, depending on the composition of the water/surfactant/oil/asphaltene system. The nanoemulsions containing xylene as the oil phase destabilized the emulsions the fastest. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44174.     

Paraffin Oil Emulsions for the Absorption of Toluene Gas

Water‐in‐oil‐in‐water (W/O/W) and water‐in‐oil (W/O) emulsions of paraffin oil were prepared with sorbitan monooleate (Span 80)/polyoxyethylene sorbitan monooleate (Tween 80) or polyethylene glycol monostearate (SG‐6), respectively. The physical characteristics and the absorption of toluene gas in these emulsions were investigated to evaluate the influence of the emulsifier dosage and the oil/water ratio. Both investigated W/O/W emulsions provided high stabilities and low viscosities. The absorption of toluene gas was excellent, with little foam occurring during the absorption. Although the W/O emulsions with 2–5 % SG‐6 were of high stability, their high viscosities strongly limited their application as volatile organic compound absorbents. Stable emulsions consisted of small and uniform droplets and some emulsions underwent mild demulsification after the absorption.     

CO2‐Switchable Oil/Water Emulsion for Pipeline Transport of Heavy Oil

By mixing an aqueous solution of tertiary amine, N,N‐dimethylethanolamine (DMEA), with naphthenic acid (RCOOH) derived from heavy oil, a CO₂ switchable zwitterionic surfactant (RCOO^?DMEAH⁺) aqueous system was constructed. The CO₂ switchability of this zwitterionic surfactant was confirmed by visual inspection, pH measurements, and conductivity tests, i.e., the RCOO^?DMEAH⁺ decomposed into RCOOH, DMEAH⁺ and HCO₃^? after bubbling CO₂ through but switched back to its original state by subsequent bubbling N₂ through at 80 °C to remove the CO₂. The interfacial tension tests of heavy oil in DMEA aqueous solutions indicated that the solution containing 0.5 wt% of DMEA and 0.2 wt% of NaCl resulted in the lowest interfacial tension. The O/W emulsion formed when aqueous solutions of DMEA were used to emulsify heavy oil exhibited the best performance when the oil/water volume ratio, DMEA concentration, and NaCl concentration were 65:35, 0.5 and 0.2 wt%, respectively. The feasibility of pipeline transport of the O/W heavy oil emulsion was evaluated. The results illustrated that the demulsification of the O/W emulsion after transport could be easily realized by bubbling CO₂ through. Although demulsification efficiency still needs to be improved, the recycling of the aqueous phase after demulsification by removal of CO₂ looks promising.     

W/O型油水乳化液物理破乳技术及装置研究进展

综述了石油原油或废油中W/O型油水乳化液物理破乳技术及装置的研究现状及发展趋势,分别从施加外力破乳和施加场能破乳两个方面介绍了W/O型油水乳化液的物理破乳技术及装置各自的优缺点。施加外力破乳技术及装置方面,重点介绍了施加离心力破乳的旋流破乳装置、施加聚结力破乳的聚结板式破乳装置和施加压力破乳的膜破乳装置;施加场能破乳技术和装置方面,重点介绍了施加微波场的微波破乳装置、施加超声场的超声波破乳装置以及施加电场的电破乳装置;并着重阐述水击谐波破乳技术及装置的工作机理、结构及工作流程。最后指出破乳技术及装置研究方向为装置的新型化、节能环保化、智能化以及轻量化。     

高频脉冲电场作用下乳状液液滴动力学模型

基于乳状液中液滴在电场中的受力情况的分析,建立了W/O乳状液中液滴振荡固有频率公式,从理论角度分析和解释了高频脉冲电场对W/O乳状液的破乳机理,从力学的角度分析了最佳频率存在的理论基础,并推导出了最佳频率的计算公式。该固有频率与液滴尺寸、界面张力、黏度、温度、密度等有关。为了验证最佳频率公式的可靠性,用正辛烷乳状液进行了室内实验。实验结果表明,理论最佳频率公式的预测结果与实验测得的最佳频率结果吻合,经修正后与白油实验结果也非常接近。     

Synthesis and characterization of stearyl‐group‐terminated dendrimers and thermosensitivity of their toluene solutions

Stearyl‐group‐terminated poly(ester amide) dendrimers [PEAD (R)₃ and PEAD (R)₈] and a poly(amino amide) dendrimer [PAMAM (R)₄] were synthesized by the amidation of three, eight, and four terminated primary amino groups in poly(ester amine) dendrimers and a poly(amino amide) dendrimer with stearyl chloride. The dendrimer structures were characterized with IR and elemental analysis. The toluene solutions of the stearyl‐group‐terminated dendrimers were thermosensitive. Not only did gels form in PEAD (R)₃–, PEAD (R)₈–, and PAMAM (R)₄–toluene solutions below 57.5, 60, and 49°C, respectively, but the content of toluene in the gels depended on the temperature, and a break existed at about 30°C. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 341–346, 2005     

二元聚合物的合成及在稠油破乳中的应用

采用丙烯酸（AA）与自制丙烯酸壬基酚聚醚酯（NPEAA）为原料,在偶氮二异丁腈（AIBN）为引发剂,甲苯为溶剂的条件下,引发聚合制备了二元共聚物稠油破乳剂,采用FTIR、1HNMR对产物结构进行了确证,GPC测试了分子量;采用荧光光谱仪与表面张力仪测得其临界胶束浓度(CMC)为0.5g/L,表面张力为25.684mN/m。并以脱水率和脱出污水含油量为衡量指标,探讨了不同因素下聚合物破乳剂对陈庄稠油W/O乳液的破乳脱水性能,确定最佳破乳条件：温度55?C,时间2h,用量0.5g/L时,脱水率为88.5%,脱出水中含油量为198.4mg/L。研究了聚合物破乳剂对乳状液表观粘度、体系稳定性、油水界面的影响以及微观破乳过程,探讨分析得出聚合物破乳剂在油水界面更易润湿扩散,脱水速率快,破乳效果好。     

Predicting the Viscosity of Non‐Newtonian Water‐in‐Oil Emulsions Based on the Lederer Model

The accurate prediction of the viscosity of emulsions is highly important for oil well exploitation. Commonly used models for predicting the viscosity of water‐in‐oil (W/O) emulsions composed by two or three factors cannot always fit well the viscosity of W/O emulsions, especially in the case of non‐Newtonian W/O emulsions. An innovative and comprehensive method for predicting the viscosity of such emulsions was developed based on the Lederer, Arrhenius, and Einstein models, using experimental data. Compared with the commonly applied W/O emulsion viscosity models, the proposed method considers more factors, including temperature, volume fraction of water, shear rate, and viscosity of the continuous (oil) and dispersed phase (water). Numerous published data points were collected from the literature to verify the accuracy and reliability of the method. The calculation results prove the high accuracy of the model.     

Preparation and in vitro release behavior of urapidil hydrochloride loading into microspheres based on poly(L‐lactide)

Microencapsulation of the antihypertensive drug urapidil hydrochloride was investigated as a means of controlling drug release and minimizing or eliminating local side effects. Poly(L ‐lactide) (PLLA) microspheres were prepared using an alternative oil‐in‐water (O/W) solvent‐evaporation method such as the O/W cosolvent solvent‐evaporation method and O/W with various electrolytes added to the aqueous phase method. The surface morphology and the size of the microspheres were observed by scanning electron microscope. Meanwhile, the drug loading efficiency of microspheres and the in vitro release of urapidil hydrochloride from microspheres were performed. The release study indicated that the urapidil hydrochloride‐PLLA microspheres exhibited better sustained release capacity, and the kinetics of urapidil hydrochloride‐PLLA microspheres in vitro release could be described by the Higuchi equation. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Plasma Polymerization Modified Polyvinylidene Fluoride (PVDF) Membrane Development and Characterization for Degumming of Soybean Oil

Unmodified and surface‐modified polyvinylidene fluoride (PVDF) membranes were tested for their ability to degum soybean crude oil and crude oil miscellas. The membrane was modified with 1,1,1,3,3,3‐hexafluoro‐2‐propanol or hexamethyldisiloxane (HMDSO) by radio‐frequency plasma polymerization at 10–100 W glow discharge power and 1–30 min contact time. The membranes were characterized by contact angle measurements, attenuated total reflectance Fourier transform infrared spectroscopy, atomic force microscopy, and scanning electron microscopy. Modification of the PVDF membrane with HMDSO at 60 W power for 5 min increased the interfacial free energy between water and solid surface from 30 ± 2 to 64 ± 2 mJ/m². This membrane was tested for permeate flux and phospholipid rejection with crude oil and different concentrations of miscella. Although formation of the polymer film on the membrane tended to decrease membrane pore size, the modified membrane had an oil flux as good as the unmodified membrane did. In addition, the modified‐membrane improved the phospholipid rejection and removed 76 % of the phospholipids from the crude oil and 81–90 % of the phospholipids from crude oil miscellas.     

无机盐存在下微波辐射超稠原油脱水研究

由于超稠油粘度高、密度大，胶质、沥青质含量高，油水界面膜强度大，常规化学沉降脱水法以及电化学脱水法难以达到理想的脱水效果。采用添加无机盐的微波辐射法脱水，脱水效果大大提高。微波辐射3min，系统压强0．1MPa，辐射功率225W，静置沉降1min，研究了氯化钠、碘化钠、醋酸钠、硝酸钠、碳酸钠、硫酸钠6种钠盐以及氯化钠、氯化钾、氯化钙、氯化钡、氯化镁、氯化铝6种氯化物对微波辐射超稠原油脱水率以及对脱出水的透光率的影响，简要分析了无机盐作用下W／O型乳状液吸收微波的机理。结果表明，极少量的无机盐能大大提高原油的微波破乳效果，尤其是在醋酸钠的存在下，脱水率达到了99．43％。阳离子对微波破乳的影响与阳离子的极化力有关，阴离子对微波破乳的影响与阴离子半径大小有关。     

Wettability reversal of reservoir rock surface through surfactant stabilized microemulsion

In the process of the tertiary recovery of oil and gas resources, it is necessary to use external fluids to displace the crude oil in the reservoir. Whether the crude oil on the surface of the rock can be effectively displaced and the wettability of the rock can be changed to avoid re-adsorption by the crude oil is directly related to the level of oil recovery. Therefore, it is critical to study the cleaning and wettability reversal of reservoir rock surface. Because microemulsions have outstanding performance in changing the wettability of rocks and solubilizing crude oil, this paper uses cetyl trimethyl ammonium bromide (CTAB) as a surfactant and n-butanol as a co-surfactant to prepare microemulsions. The performance of microemulsions with different microstructures on the cleaning and wettability changes of crude oil on the rock surface were studied. The results show that the water-in-oil (W/O) microemulsion has good cleaning efficiency, and the oil removal rate on the sandstone core surface can reach 79.65%. In terms of changing the wettability of the rock surface, W/O, bi-continuous phase (B.C.) and oil-in-water (O/W) microemulsions can change the core surface from lipophilic to hydrophilic. And the effects of the B.C. and O/W microemulsions are more obvious. The microemulsion system that was prepared based on cationic surfactants has a good application prospect in changing the wettability of the reservoir and cleaning the adsorbed crude oil.     

低压脉冲电场对高浓度O/W型乳化液破乳特性的影响

为实现高含油浓度O/W型乳化液的电场破乳预分水,借鉴电絮凝技术的工作原理自行设计了静态序批式电场破乳预分水实验装置。在对乳化液理化特性进行量化表征以确保其稳定性的基础上,以预分水率为主要评价指标,系统实验研究了电场形式、峰值电压、脉冲频率、占空比及含水率对O/W型乳化液静态破乳预分水特性的影响。结果发现,脉冲直流方波电场下乳化液的破乳效果比直流电场较好;含水率降低使乳化液的破乳程度减弱;峰值电压、脉冲频率和占空比都存在一个最优值。当施加脉冲直流方波电场、电压幅值为40V、脉冲频率为2kHz、占空比为0.5、加电时间为30min时,含水率90%乳化液的预分水率达87.18%。基于实验过程中的现象推测,高含油浓度O/W乳化液的破乳预分水机理包括双电子层作用和类似电絮凝作用。     

超声波对西峰油田原油破乳脱水的实验研究

超声波原油破乳是一种很有发展前景的新型破乳方法,文中给出了超生波原油破乳的基本原理,利用超声波对原油在实验室进行了破乳脱水实验,研究了声强、频率、温度、辐照时间对超声波原油破乳脱水的影响。试验结果表明,超生波参数有一个最佳值或范围,声强为0.61 W/cm2、频率20 kHz、辐照时间5～10 min。     

Synthesis and characterization of emulsion polymerized mixed matrix aluminum silicate/poly(2,6‐dimethyl 1,4‐phenylene oxide) films

A series of poly (2,6‐dimethyl‐1,4‐phenylene oxide) (PPO)‐based organic/inorganic films for the potential application in membrane gas separation were prepared by employing a method in which aluminum hydroxonitrate contained in a stable water‐in‐oil (W/O) emulsion, the oil phase being a solution of PPO in trichloroethylene, was mixed with a homogeneous solution of PPO in trichloroethylene containing tetraethyl orthosilicate (TEOS). Inorganic polymerization occurred in or at the surface of the aqueous droplets of the W/O emulsion. Subsequently, thin films were prepared by a spin coating technique, and they were referred to as emulsion polymerized mixed matrix (EPMM) films. Scanning electron micrographs taken from a film cross section indicated the presence of particles in the PPO matrix, and energy dispersive X‐ray measurements showed that the embedded particles contained Al and Si elements. Differential scanning calorimetry analysis showed a decrease in the glass transition of the EPMM films with increase of TEOS loading. The compatibility between aluminum silicate nanoparticles and PPO in the EPMM films was confirmed by air separation tests. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Development of a Continuous Electric Coalescer of W/O Emulsions in Liquid Surfactant Membrane Process

Abstract

The development of an efficient, continuous demulsification apparatus is needed in the industrial separation process utilizing the liquid surfactant membrane technique. A test apparatus for continuous demulsification was constructed in which a pulsed dc high potential is applied to W/O emulsions flowing between parallel copper electrodes of a perforated plate. Efficient demulsification was achieved by an operation in which the demulsified oil phase was absent between the emulsion and the upper electrode. When the feed rate of emulsion was adjusted to be equal to the demulsification rate, the latter value was proportional to the square root of the applied potential and independent of the distance between the electrodes.