Screening and Demulsification Mechanism of Fluorinated Demulsifier Based on Molecular Dynamics Simulation

In order to solve the problem of demulsification difficulties in Liaohe Oilfield, 24 kinds of demulsifiers were screened by using the interface generation energy (IFE) module in the molecular dynamics simulation software Materials Studio to determine the ability of demulsifier molecules to reduce the total energy of the oil–water interface after entering the oil–water interface. Neural network analysis (NNA) and genetic function approximation (GFA) were used as technical means to predict the demulsification effect of the Liaohe crude oil demulsifier. The simulation results show that the SDJ9927 demulsifier with ethylene oxide (EO) and propylene oxide (PO) values of 21 (EO) and 44 (PO) reduced the total energy and interfacial tension of the oil–water interface to the greatest extent, and the interfacial formation energy reached −640.48 Kcal/mol. NNA predicted that the water removal amount of the SDJ9927 demulsifier was 7.21 mL, with an overall error of less than 1.83. GFA predicted that the water removal amount of the SDJ9927 demulsifier was 7.41mL, with an overall error of less than 0.9. The predicted results are consistent with the experimental screening results. SDJ9927 had the highest water removal rate and the best demulsification effect. NNA and GFA had high correlation coefficients, and their R²s were 0.802 and 0.861, respectively. The higher R² was, the more accurate the prediction accuracy was. Finally, the demulsification mechanism of the interfacial film breaking due to the collision of fluorinated polyether demulsifiers was studied. It was found that the carbon–fluorine chain had high surface activity and high stability, which could protect the carbon–carbon bond in the demulsifier molecules to ensure that there was no re-emulsion due to the stirring external force.     

Synthesis and Demulsibility of the Terpolymer Demulsifier of Acryl Resin

Terpolymer demulsifier of acryl resin has been synthesized through solution polymerization with water as a dissolvent, potassium persulfate as an initiator and the monomers of methyl methacrylate, butyl acrylate and acrylic acid as starting materials. The effects of the reaction temperature, dripping time, the amount of monomers and initiator on the dehydration rate of the demulsifier were investigated by an orthogonal experiment. It shows that the stronger influence on the dehydration rate among six factors is reaction temperature, dripping time, and amount of catalyst, while monomer has weak influence. The performance of the demulsifier was evaluated under different demulsification time, temperatures and concentrations of the screened demulsifiers. The result shows that the dehydration rate of the demulsifier can reach over 67%, which is better than that by the emulsion polymerization way.     

Characterization of mechanical properties of jute/PLA composites containing nano SiO2 modified by coupling agents

Although jute fiber-reinforced PLA composites show strong application prospects, their low mechanical properties limit their applications to some extent. In this paper, nano-SiO₂ particles as well as nano SiO₂ modified by coupling agents which can efficiently improve the strength and toughness of composite materials are introduced into the PLA matrix. The bending, stretching and thermal properties of designed jute/PLA nonwoven composites were studied. The study shows that the nano-SiO₂ particles are beneficial to the interface performance between the PLA matrix and jute leading to improvement in the mechanical properties and thermal stability. Moreover, thermomechanical properties indicate that the addition of SiO₂ can improve the jute/PLA interfacial adhesion and increase the glass transition temperature of the material. Finally, toughening mechanism of nano-SiO₂ particles in the jute/PLA composite was analyzed.

     

Synthesis and evaluation of demulsifiers with polyethyleneimine as accepter for treating crude oil emulsions

Demulsifiers provide an important means of breaking water‐in‐crude oil, which are formed during crude oil exploitation. In present work, twenty polyether copolymers based on polyethyleneimine (PEI) were synthesized. The interfacial properties of the PEI polyethers at the water‐crude oil interface were described by interfacial tension (IFT) and interfacial dilational modulus. The effects of position isomerism, size of intermediate and ratio of ethylene oxide (EO)/propylene oxide (PO) on the demulsification efficiency of these polyethers were studied. The results show that different positions of the EO and PO in copolymers lead to huge difference in both interfacial properties and demulsification performance. Polymers with hydrophilic core and hydrophobic tails (Ex‐mn series) are not efficient on demulsification of water‐in‐oil emulsion whereas polymers with hydrophobic core and hydrophilic tails (Px‐mn series) are. Meanwhile, Px‐mn series show higher IFT and lower interfacial dilational modulus than Ex‐mn series. In the same series, the IFT and interfacial dilational modulus decrease with decreasing EO/PO ratio. In the series with best demulsification performance (P199‐mn series), 60 min water removal rates of the polymers increase with decreasing EO/PO ratio at 65°C. In other words, the longer the hydrophobic blocks of polymers, the stronger the demulsification capacity. The effect of concentration of demulsifier on the demulsification efficiency was also investigated. Copyright © 2015 John Wiley & Sons, Ltd.     

Synthesis and Evaluation of New Demulsifiers Incorporating Linear Alkyl Benzene Moiety for Treating Water-in-Oil Emulsion

In the present study, five types of water soluble demulsifiers based on linear alkyl benzene were prepared. The chemical structures of the prepared demulsifiers were elucidated using Fourier transform-infrared (FTIR) and ¹H NMR spectra. Different factors affecting demulsification efficiency such as; water content, demulsifier concentration, hydrophilic lipophilic balance (HLB), and ethylene oxide unit were investigated. Also, the rheological properties in relation to demulsification efficiency were studied. The surface and thermodynamic parameters of the prepared demulsifiers were determined at 25°C including, surface tension (γ) and effectiveness, maximum surface excess (Γ_max), and minimum surface area (A_min). From the obtained data, it was found that the demulsification efficiency increases with increasing the water content and concentration of the demulsifiers. Primarily evaluation study of demulsification performance of the new demulsifiers showed that as the ethylene oxide unit in the demulsifiers increase (10–40 ethylene oxide units), the performance of the demulsifiers increasing, however, it decrease in case of demulsifiers with (80 ethylene oxide unit).     

Demulsification by increasing the gravitational force acting upon the dispersed phase owing to the adsorption/absorption of the magnetite particles

Demulsification using a magnetic demulsifier is commonly used to separate emulsions using an external magnetic field. However, this study presents a new demulsification method based on the increased weight of the dispersed phase due to the adsorption/absorption of the magnetite particles by the droplets. Micron-sized bare magnetite particles were used as the demulsifier in this method which does not necessarily need to apply a surface-active additive and the magnetic field for the demulsification. Magnetic responsivity of the demulsifier can only be used for the recovery of the demulsifier. The demulsification experiments were performed using the oil-in-water and water-in-oil emulsions. The effect of temperature, wettability, demulsifier dosage and activity, sedimentation rate and particles size were investigated. The results showed that the proposed method can remarkably improve the efficiency and speed of the demulsification, and has a great potential to be considered for the commercialization.     

Acrylic emulsifier-free emulsion polymerization containing hydrophilic hydroxyl monomer in the presence or absence of nano-SiO2

The acrylic emulsifier-free emulsion polymerization containing hydrophilic hydroxyl monomer (23 wt.%) in the presence or absence of nano-SiO₂ particles was studied. The effects of reaction temperature, level of nano-SiO₂, variation of core monomer composite on the coagulum, particle size and monomer conversion were investigated. Transmission electron microscopy (TEM) was used to observe the particle morphology in the presence of nano-SiO₂ particles. It showed that the systems produced larger size of particles than that with emulsifier, and the addition of nano-SiO₂ particles increased the particle size but decreased the coagulum. When polymerization temperature rose from 65 °C to 80 °C, the coagulum produced decreased greatly irrelative of the existence of nano-SiO₂, and the particle size decreased with nano-SiO₂ but increased without nano-SiO₂. The increase of level of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) in core monomer composite all decreased particle sizes; furthermore, the level of AA had more efficiency than the level of HEMA irrespective of the existence of nano-SiO₂ particle.     

Effects of surface modification of fumed silica on interfacial structures and mechanical properties of poly(vinyl chloride) composites

Poly(vinyl chloride) (PVC)-based composites were prepared by blending PVC with nano-SiO₂ particles, which were treated with dimethyl dichlorosilane (DMCS), γ-methylacryloxypropyl trimethoxy silane (KH570). The dispersion and interfacial compatibility of nano-SiO₂ particles in PVC matrix was characterized by SEM, which indicated that DDS had a better dispersion and compatibility than UTS but worse than KHS. The mechanical properties, processability and effective interfacial interaction of nano-SiO₂/PVC composites were studied. The nano-SiO₂ particles treated with KH570 or DMCS significantly reinforced and toughened the PVC composites. The maximum impact strength of PVC composites was achieved at a weight ratio of nano-SiO₂/PVC:4/100. The tensile yield stress increased with increasing the content of treated inorganic particles. The incorporation of untreated nano-SiO₂ particles adversely affected the tensile strength of the composite. Although the equilibrium torques of all nano-SiO₂/PVC composites were higher than that of pure PVC, the surface treatments did reduce the equilibrium torque. The interfacial interaction parameter, B, and interfacial immobility parameter, b, calculated respectively from tensile yield stress and loss module of nano-SiO₂/PVC composites, were employed to quantitatively characterize the effective interfacial interaction between the nano-SiO₂ particles and PVC matrix. It was demonstrated that the nano-SiO₂ particles treated with KH570 had stronger effective interface interaction with PVC matrix than those treated with DMCS, which also had stronger effective interface interaction than the untreated nano-SiO₂ particles.     

破乳剂对复合驱乳状液的破乳机理研究

针对模拟采出液和三元复合驱矿场采出液,研究了破乳剂对复合体系界面张力和膜强度的影响.破乳剂浓度增加,二元复合体系界面张力降低,而三元复合体系界面张力升高.破乳剂分子部分顶替乳化剂分子并显著降低了界面膜强度.     

In situ synthesis of poly(ethylene terephthalate-<Emphasis Type="Italic">co</Emphasis>-isophthalate)–SiO<Subscript>2</Subscript> nanocomposites and their optical properties

In this paper, poly(ethylene terephthalate-co-isophthalate) was prepared and a series of PETI/SiO₂ nanocomposites with different amounts of silica nanoparticles was synthesized by in situ polymerization. Optical properties of the resultant nanocomposites were investigated by WGW photoelectric haze meter and UV–Vis-NIR spectrophotometer. Chemical structure and its influence on spherulite size of nano-SiO₂ were characterized by Fourier transformed infrared spectra and polarized optical microscopy, respectively. The differential scanning calorimetry results reveal that the addition of nano-SiO₂ has an impact on the thermal performance of the nanocomposite. Different proportions of SiO₂ were compared and the degree of crystallinity was found to have influence on optical properties of as-prepared nanocomposites. In addition, the results indicate that the low loading levels of SiO₂ can improve the optical properties of the composite and an optimum content was selected. Possible reasons for this enhanced role might be the different combination structure of the nanocomposites when the amount of SiO₂ varied.     

支状嵌段聚醚的界面聚集行为及对原油乳状液的破乳作用

合成了三种不同聚氧丙烯/聚氧乙烯(PPO/PEO)比例的含苯环支状嵌段聚醚, 通过界面张力、界面流变、表面压以及对原油乳状液的破乳脱水效果的测定, 考察了其界面聚集行为和破乳作用对PEO含量和分子量的依赖性, 并且对比研究了三种支状聚醚分子交联前后的破乳性能. 结果表明, PEO含量高且分子量大者,其单分子界面占据面积大, 在油/水界面达到吸附平衡的时间短, 其油/水界面扩张模量及扩张弹性均高于PEO含量较少者. 但是对原油乳状液的破乳脱水效果则是PEO含量居中的聚醚最好. 温度影响和交联与否的研究表明, 交联并不能提高分子量较大的聚醚对原油乳状液的破乳效果, 温度对聚醚分子交联前后的破乳效果有不同的影响规律. 本研究可为原油集输过程中化学品的选择与应用提供一定的依据.     

Preparation of acrylic resin/modified nano-SiO<Subscript>2</Subscript> via sol-gel method for leather finishing agent

Acrylic resin/nano-SiO₂ (AR/nano-SiO₂) composite was prepared by physical blends of acrylic resin (AR) and nano-SiO₂, which was synthesized via the sol-gel method of tetraethoxysilane (TEOS) catalyzed with alkali. The synthetic conditions, such as surfactant type, the content of nano-SiO₂ sol, stirring speed, mixed temperature and ultrasonic treatment, on nanocomposites’ property were studied in detail. DSC indicated the glass transition temperature of AR/nano-SiO₂ (Tg = −26.7°C) was a little higher than that of the acrylic resin (Tg= −29.6°C). Water uptake confirmed that the water resistance of AR/nano-SiO₂ was improved by 55.94% and the solvent resistance by 54.79% when compared with AR. The improved properties of leather finished by AR/nano-SiO₂ were shown, in contrast to AR treatment; water vapor permeability was increased by 9.15% and the finish adhesion by 10.35%.     

Hybrid cyclotriphosphazene–polysiloxane–nano-SiO2 composites with improved mechanical properties

Starting from the functional cyclotriphosphazene, polysiloxane and nano-SiO₂ precursors, three new hybrid nanocomposites with reinforced mechanical properties were prepared. Young’s modulus values for all the composite samples are similar in the range of 7–11 MPa, stress at fracture increases with the nano-SiO₂ content increase in the material and reaches a maximum value of 36 MPa for the composite with 20% nano-SiO₂. The nanocomposites investigated are elastic and demonstrate the ability to be deformed without failure up to 54% strain.     

Synthesis and structural chemical examination of faujasite type zeolite and its new structural modification

On the basis of the aluminate solution of alumina production and sodium silicate a faujasite-type zeolite was synthesized as well as its new structural modification. Thermostability nature and temperature of dehydration of this zeolite were found. It is shown that the ratio of the starting components SiO₂/Al₂O₃ and Na₂O/Al₂O₃ greatly affects the direction of the crystallization of zeolites.     

Influence of Asphaltene Concentration on the Interfacial Properties of Two Typical Demulsifiers

Oil-in-water emulsion is an innovate manner by which heavy crude oil can be transported from producing sites to transforming sites through pipelines. The effect of emulsifier on the interfacial properties and demulsification performance of demulsifier for heavy crude oil–in-water emulsion has been studied by many researchers. However, the influence of asphaltene in heavy crude oil on the interfacial properties of demulsifier has not been investigated yet. In this article, the influence of asphaltene concentration of two typical demulsifiers (straight-chained SP-1 and branch-chained AE-1) was systematically studied in terms of absorption thermodynamics, absorption kinetics, and coalescence kinetics. The results revealed that the demulsifier adsorption was a ΔS controlled spontaneous process. The absolute value of ΔG of SP-1 adsorption was found to decrease with asphaltene concentration, whilst the asphaltene concentration had no significant influence on that of AE-1. With the increase of asphaltene concentration, the demulsifiers’ adsorption rates increased, but the reorganization rates on the interface decreased. Coalescence speed of asphaltene droplet decreased with asphaltene concentration in spite of demulsifier type. Additionally, AE-1 had higher absolute value of ΔG, adsorption speed, and coalescence speed than that of SP-1 at the same condition.     

Investigation of the Demulsification Efficiency of Some Ethoxylated Polyalkylphenol Formaldehydes Based on Locally Obtained Materials to Resolve Water-in-Oil Emulsions

Fourteen ethoxylated polyalkylphenol formaldehyde surfactants were prepared from locally sourced raw materials. These surfactants were used as demulsifiers to resolve asphltenic crude oil emulsions. Different factors affecting demulsification efficiency such as water:oil ratios, surfactant concentration, surfactant molecular weight, ethylene oxide content, alkyl chain length, and asphaltene content were investigated. From the data obtained it was found that the demulsification efficiency increases by increasing the concentration, alkyl chain length and water content in the emulsion. Also it was found that the increase of asphaltene content in the crude oil impeded the demulsification efficiency. The effect of molecular weight was studied and it was found that the demulsification efficiency was controlled by an optimum range of molecular weight between 3640 to 3810 for the family of demulsifiers studied. Regarding the effect of ethylene oxide content in the demulsifier structure, it was found that the maximum demulsification efficiency was obtaind at 40 units ethylene oxide. The maximum demulsification efficiency was obtained by TND5 (m.wt. = 3800, eo = 40 units). With this demulsifier 100% water separation was exhibited after 35 minutes at 150 ppm demulsifier concentration and 50% w/o emulsion. The surface, interfacial tension, and hydrophilic lipophilic balance (HLB) of the invistigated demulsifers were studied. The obtained results justified that they are strongly related to the demulsification effeciency.     

Antiwettability enhancement of PVDF-HFP membrane via superhydrophobic modification by SiO2 nanoparticles

Pore wetting is undesirable in the membrane gas–liquid separation process as it deteriorates the gas removal flux. To alleviate the affinity of a membrane surface toward a liquid solvent, its hydrophobicity needs to be enhanced. In this study, a superhydrophobic polyvinylidene fluoride-co-hexafluoropropylene membrane was synthesized via a simple and facile nonsolvent-induced phase inversion process. Hydrophobic nano-SiO₂ particles were used as solvent additives to improve the wetting resistance of the membrane. The results revealed that blended nano-SiO₂ membranes exhibited enhanced surface hydrophobicity in terms of water contact angle. Such improvement was attributed to the enhancement of surface roughness via the formation of hierarchical multilevel protrusions. Besides, the embedment of nanoparticles in polymer spherulitic globules also contributed to the reduction in surface energy of the membrane. As a result, the blended nano-SiO₂ membrane achieved superhydrophobicity with a water contact angle of up to 151°.     

The Effect of Nano-SiO2 Colloid on Soap-free Emulsion Polymerization of Methyl Methacrylate and Hydroxyethyl Methacrylate

Soap-free emulsion polymerization of methyl methacrylate (MMA) and hydroxyethyl methacrylate (HEMA) was carried out in the presence of colloidal nano-SiO₂ particles. The effect of nano-SiO₂ level on the monomer conversion, polymerization rate (Rp), and emulsion stability was investigated. The viscosity, particle size distribution of the emulsions, surface tension, and ionic conductivity of these systems were determined. Upon the introduction of the nano-SiO₂ particles into this system, the Rp and monomer conversion increased and the average particle size of the P(MMA-HEMA) emulsion decreased in comparison to emulsions formed in the absence of nano-SiO₂. However, the particle size distribution became broader to some degree. Scanning electron microscope observations demonstrated that the shape of these latex particles were uniformly spherical. The surface tension and ionic conductivity of the system increased significantly after polymerization, but the presence of nano-SiO₂ resulted in an increase in surface tension and a decrease in ionic conductivity in comparison to the particle–free system.     

Electrochemical reduction of nano-SiO2 in hard carbon as anode material for lithium ion batteries

A composite of silica (SiO₂) and hard carbon was prepared by hydrothermal reaction. Special attention was paid to the characterization of the possible electrochemical reduction of nano-SiO₂ in the composite. Evidence by solid-state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) and high lithium storage capacity of the composite prove the electrochemical reduction of nano-SiO₂ and the formation of Li₄SiO₄ and Li₂O as well as Si in the first-discharge. The reversible lithium storage capacity of the nano-SiO₂ is as high as 1675 mAh/g.     

十八烷基超支化分子的结构表征与破乳性能

以甲醇为溶剂,用十八胺、丙烯酸甲酯和乙二胺为原料,通过迈克尔加成反应和酰胺化缩合反应,制备了1.0 G超支化分子;通过红外光谱、核磁共振手段对合成产品的结构进行了表征,且考察了十八烷基超支化分子对O/W型原油模拟乳液的破乳性能,并与传统的线性破乳剂SP-169进行了对比.结果表明:在温度为50℃、添加量为20 mg/L、破乳时间为120 min的条件下,其脱水率达到了76.2%,脱出水中的含油量为41.9 mg/L;而破乳剂SP-169在相同的条件下的脱水率为61.5%,脱出水中的含油量为52.4 mg/L.