固体粒子稳定的乳状液研究进展

综述了固体粒子对乳状液稳定性影响的有关研究进展。微细不溶的固体粒子构成重要的一类乳化剂,被水相和油相部分润湿的固体粒子能够有效地稳定乳状液。固体粒子稳定乳状液的效果取决于以下因素:粒子大小、粒子间相互作用和粒子的润湿性质。固体粒子存在的油-水界面表现出粘弹行为,这种粘弹界面膜可大大地提高空间位阻,减缓乳状液液珠间液膜变薄的速率,从而提高乳状液地稳定性。原油中的粘土、胶质、沥青质和石蜡等胶体粒子被证明对乳状液的稳定性起很大的作用。     

烷基芳基磺酸钠对烷烃的乳化性能

采用分水时间法考察了结构明确的高纯度烷基芳基磺酸钠在烷烃中的乳化现象。 以液态石蜡为油相,讨论了乳化剂浓度对乳状液稳定性的影响,确定了最适宜的乳化剂浓度,并研究了烷基链长度、芳基结构和芳基在烷基链位置对形成的乳状液稳定性的影响关系,考察了不同油相对乳状液稳定性的影响。 结果表明,最适宜的乳化剂质量分数为0.1%;当固定芳基结构时,随着烷基链上碳数的增加,乳状液稳定性线性增强;当固定烷基链碳数时,随着芳基上碳原子的增加,乳状液稳定性增强;随着芳基位置向烷基链中间位置移动,乳状液稳定性增强;随着油相分子量的增加,能形成稳定乳状液所需的乳化剂的分子量随之递增。     

研磨破乳的规律及其机理

报道了研磨破乳的实验规律，讨论了研磨破乳的基本步骤：（１）过滤过程中乳状液内相液滴在研磨剂表面铺展成膜并进一步聚结──过滤破乳；（２）研磨剂的相互碰撞使乳状液的分散液滴受到摩擦力和剪切力，导致液滴聚结──研磨破乳。     

用混合乳化剂制备不同粒径的乳状液

乳状液按其颗粒大小可分为普通乳状液（约IN10pm，微小乳状液（01～0·4Pm），微乳状液（001卜0．lPm）．其中微小乳状液比普通乳状液颗粒小，分散均匀，稳定性好，比微乳状液所需乳化剂的用量要低得多，在实际应用中很有前景．但有关微小乳状液的研究工作做得很少［’－‘］．在乳化过程中，若不需外界做功，靠乳化剂的自身作用，使两种不相混溶的液体自动混合，生成乳状液称为自发乳化，无需专门的乳化设备即可方便地制备出乳状液．目前自发乳化所得的乳状液颗粒都较大，稳定性较差卜一＼若将微JJ、乳状液的制备与其自发形成的条件结合…     

功能化磁性纳米粒子在乳状液制备及破乳中的应用及作用机制

功能化磁性纳米粒子因其独特的理化性质,在乳状液制备与破乳领域的应用受到广泛关注。本文归纳了功能化磁性纳米粒子的制备方法、合成结构与特征性质,阐述了其在乳状液制备及破乳中的应用过程,重点分析了磁性纳米粒子在溶液中良好分散、稳定吸附于油水界面排布为膜结构的作用行为,尤其是磁性纳米粒子的磁响应特征对乳状液中界面性质、液滴形貌及运动状态的影响,并进一步总结出其表面性质及作用行为对稳定乳状液或使乳状液破乳的规律。针对磁性纳米粒子对乳状液稳定性影响规律的探究可为其在应用领域提供理论支持。最后本文就功能化磁性纳米粒子研究中亟待解决的新问题作出展望。     

Pickering多重乳状液的一步法合成及形成机理研究

使用锂皂石层状纳米颗粒与表面活性剂(Span80)复配制备乳状液的过程中, 在乳化之前对锂皂石颗粒水分散体系进行稀释, 则可以通过一步法制备出性能稳定的W/O/W型Pickering多重乳状液. 研究了Span80浓度、锂皂石浓度以及稀释用水的量对生成乳状液的类型及稳定性的影响规律, 对一步法合成Pickering多重乳状液的成因及机理进行了探讨和分析. 实验结果表明, 对锂皂石颗粒水分散体系的稀释是一步法合成稳定Pickering多重乳状液的关键因素, 稀释用水的量决定了多重乳状液中的内水相体积. 随着Span80浓度的增加, 多重乳状液的粒径减小, 稳定性迅速增加. 锂皂石颗粒的浓度能够影响乳状液的类型, 但对乳状液的稳定性以及乳状液的粒径影响不大. 锂皂石颗粒在水分散体系中缓慢的扩散速率是一步法合成Pickering多重乳状液的主要原因.     

影响环氧树脂E-44相反转乳化的因素

研究了乳化剂的HLB值、乳化剂浓度、乳化温度、搅拌强度对环氧树脂E-44相反转乳化中临界含水量Rf值与乳状液稳定性的影响,探讨了环氧树脂E-44相反转机理。实验结果表明环氧树脂E-44从W/O向O/W相反转的发生与乳化剂的HLB值与浓度、乳化温度、搅拌强度等因素都有关,其Rf值随着乳化条件的不同是动态变化的。     

优秀原油破乳剂所具备的性能初探

原油破乳剂是国内外油田矿场所必需的化学药剂,可在针对性的破乳剂性能选择上一直缺乏系统的理论支持。由于原油组成的复杂性,加上影响形成乳化原油的因素众多,给原油破乳剂的研究工作带来许多困难。本文从原油乳状液的形成机理入手,分析了乳状液的稳定性原因、破乳机理、破乳剂分子结构性能、物化性能与破乳效果,提出了优秀的原油破乳剂所应具备的性能。     

微波辐射破乳研究进展

综述了微波辐射破乳的有关研究进展。微波辐射是一种有效的破乳手段，与重力沉降、化学、加热等破乳方法相比，能显著地加速稠油体系，含天然表面活性物质、无机盐、固体粒子、三元复合驱剂等乳状液的破乳，提高破乳效果，并且能够提高破乳脱出水的透光率。无机盐与微波辐射两种破乳方式存在加和作用，在极少量的NaCl，MgCl2，caCl2，KCl存在时，用微波辐射120～150s，破乳率可达100％。微波辐射破乳作为一种很有吸引力的破乳方法已在实验室和油田现场取得成功。     

乳状液-中空纤维膜萃取钕及其传质性能研究

采用非分散的萃取方式,将乳状液膜体系Span80/皂化D2EHPA/煤油/液体石蜡/盐酸通过中空纤维膜对钕进行了逆流萃取,研究了乳化剂浓度、乳状液与水相流量比、内相盐酸浓度、萃取时间等因素对萃取率的影响。结果表明,乳状液和水相流量越小、乳状液内相盐酸浓度越大,萃取率越高,内相富集倍数越大。将乳液循环萃取70次后,内相富集倍数达50.2,表明乳状液在中空纤维膜萃取器中对稀土有很好的萃取和富集效果。与乳状液膜的分散萃取方式相比,非分散萃取方式的萃取速率更快,而且萃余水相澄清,液膜稳定性好,泄漏少,膜溶胀小。同时还计算了非分散萃取过程基于水相的总传质系数实验值和理论值,当调节参数Kf(络合反应传质系数)的取值为3.5×10-9m.s-1,水相流量大于10×10-6m3.s-1时,实验值与理论预测值相吻合。     

Stability and demulsification of emulsions stabilized by asphaltenes or resins

Experimental data are presented to show the influence of asphaltenes and resins on the stability and demulsification of emulsions. It was found that emulsion stability was related to the concentrations of the asphaltene and resin in the crude oil, and the state of dispersion of the asphaltenes and resins (molecular vs colloidal) was critical to the strength or rigidity of interfacial films and hence to the stability of the emulsions. Based on this research, a possible emulsion minimization approach in refineries, which can be implemented utilizing microwave radiation, is also suggested. Comparing with conventional heating, microwave radiation can enhance the demulsification rate by an order of magnitude. The demulsification efficiency reaches 100% in a very short time under microwave radiation.     

Demulsification and Interfacial Properties of Crosslinking Phenol-Amine Resin Block Polyether Demulsifiers

Six novel crosslinking phenol-amine resin block polyether demulsifiers were synthesized for demulsification of surfactant-polymer flooding emulsion. The demulsification performances of these demulsifiers were investigated by conventional graduated bottle test. Their interfacial behaviors at water-oil interface were explored by dynamic interfacial tension and interfacial dilational viscoelasticity measurements. The results show that the demulsification efficiency is dependant on the hydrophilic-hydrophobic balance (HLB) value of these demulsifiers. It was also correlated to the interfacial activity and the dilational elasticity at the water-oil interface. The higher the HLB value of demulsifiers, the better the demulsification efficiency is.     

Effect of oil phase transition on freeze/thaw-induced demulsification of water-in-oil emulsions

Recently, there has been an increasing interest in the breakage of water-in-oil (W/O) emulsions by the freeze/thaw method. Most of the previous works focused on the phase transition of the water droplet phase. This paper emphasizes the effect of continuous oil phase transition. A series of oils with different freezing points were used as oil phases to produce model emulsions, which were then frozen and thawed. The emulsion whose oil phase froze before the water droplet phase did (OFBW) on cooling was readily demulsified with a dewatering ratio as high as over 80%, but the emulsion whose oil phase did not freeze when the water droplet phase did (NOFBW) was relatively hard to break. The difference in demulsification performance between them resulted from the distinction between their demulsification mechanisms via the analyses of the emulsion stability, emulsion crystallization/melting behaviors, oil phase physical properties, and wettability of the frozen oil phase, etc. For the OFBW emulsion, the first-frozen oil phase was ruptured by the volume expansion of the subsequently frozen droplet phase, and meanwhile, some liquid droplet phase was drawn into the fine gaps/crevices of the frozen oil phase to bridge droplets, which were considered to be essential to the emulsion breakage, whereas for the NOFBW emulsion, the demulsification was attributed to the collision mechanism proposed in our previous work. The findings may provide some criteria for selecting a proper oil phase in the emulsion liquid membrane (ELM) process and then offer an alternative approach to recycle the oil phase for continuous operation. This work may also be useful for emulsion stability against temperature cycling.     

无机盐对支状嵌段聚醚破乳作用的影响

通过阴离子聚合反应合成了一种七支状聚氧丙烯/聚氧乙烯(PPO/PEO)三嵌段聚醚;考察了不同无机盐存在时对原油乳状液的破乳效果的影响;通过界面张力、浊点和界面膨胀流变性的测定探讨了其界面聚集行为和破乳作用对无机盐的依赖性.结果表明,盐溶型无机离子存在时,能提高聚醚的破乳效果,而盐析型无机离子存在时,不利于聚醚的破乳作用;温度升高破乳速度加快,但45℃时脱出的水质最清.     

Demulsification of water-in-oil emulsion by using porous glass membrane

The hydrophilic porous glass membranes were used to demulsify water-in-oil emulsion, and demulsification efficiency can reach more than 96.2%. 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. It was found that pore size of membrane and transmembrane pressure can significantly affect demulsification efficiency. The smaller the pore size of the membrane, the better the demulsification efficiency. However, smaller pore size of the membrane has to be exerted a greater transmembrane pressure in order to make internal aqueous phase enter the membrane pore. Correspondingly, effect of transmembrane pressure on permeation flux of the droplets was also studied. In addition, recovered-oil phase by the demulsification were reused five times to extract cadmium from simulated aqueous waste. The results indicated that the extracting efficiency could arrive at 96.5%.     

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.     

Emulsification properties of a star-shaped anionic surfactant in oil-based drilling fluid

A novel star-shaped sulfonate surfactant, synthesized with triethanolamine, was identified as a hydrophilic emulsifier which could form a stable water-in-oil emulsion. The interfacial film strength was measured by suspension drop method. The emulsification properties of emulsions were obtained by the emulsification rate experiment and demulsification voltage measurement. The emulsion shows an excellent emulsification effect when the addition of star-shaped anionic surfactant into oil-based drilling fluid was 2.0?wt%. In addition, the properties of surfactant in drilling fluid with different adding amounts were studied by rheological properties, thermal stability analysis and filtration experiments. The results show that star-shaped anionic surfactant used as emulsifier can improve the performance in oil-based drilling fluid, which maybe provides a new idea for this type of surfactant.     

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.     

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.     

Concentration of amino acids by a liquid emulsion membrane with a cationic extractant

The concentration of -phenylalanine in a liquid emulsion membrane system was studied using a cation complexing agent, di-2-ethylhexyl phosphoric acid (D2EHPA), as a carrier. The membrane formulation, the pH in the internal phase of the acid concentration in the external phase were optimized with respect to concentration performance and membrane stability. It was found that a liquid emulsion membrane obtained by demulsification of the emulsion by an electrostatic coalescer could be reused. Based on the laboratory tests, a continuous multistage process for the concentration of amino acids was proposed (with the development of a commercial process in mind) and its technical feasibility was discussed.