阴阳离子表面活性剂混合体系对原油的乳化及增粘行为

利用阴阳离子表面活性剂复配技术,实现了高含水量原油体系的乳化及增粘.通过调整表面活性剂分子结构,解决了阴阳离子表面活性剂复配体系在油田模拟水中的溶解度问题.确定了相关体系高含水量油包水(W/O)乳状液的表面活性剂浓度,研究了可以产生高含水量油包水乳状液的油水混合体积比范围,并研究了温度、pH值、油水混合比例和离子强度对乳化及增粘作用的影响.获得了一系列具有优良乳化效果和乳状液稳定性的体系,其中部分体系粘度可增大80倍.这对于三次采油提高采收率有重要意义.     

阴阳离子表面活性剂混合体系对原油的乳化及增粘行为

利用阴阳离子表面活性剂复配技术,实现了高含水量原油体系的乳化及增粘. 通过调整表面活性剂分子结构,解决了阴阳离子表面活性剂复配体系在油田模拟水中的溶解度问题. 确定了相关体系高含水量油包水（W/O）乳状液的表面活性剂浓度,研究了可以产生高含水量油包水乳状液的油水混合体积比范围,并研究了温度、pH值、油水混合比例和离子强度对乳化及增粘作用的影响. 获得了一系列具有优良乳化效果和乳状液稳定性的体系,其中部分体系粘度可增大80倍. 这对于三次采油提高采收率有重要意义.     

淀粉微球形成过程的介观模拟及实验

以环己烷为油相、淀粉乳液为水相、Span60和Tween60为乳化剂,对淀粉微球的形成过程进行了耗散粒子动力学(DPD)模拟及实验研究.模拟结果表明,淀粉微球的形成过程存在四个阶段,即淀粉与乳化剂分子无规则分散阶段、小聚集体形成阶段、球状聚集体形成阶段和稳定平衡阶段,并且发现油水比是影响聚集体是否能形成球状的关键因素.油水比小于7的条件下,油水两相分离较难,水相呈现片状、十字型状、柱状及椭球状等形状;当油水比增加到8,水相能形成微球且微球粒径随油水比增加而减小.同时实验结果表明,油水比为8时,微球粘连,几乎看不清球状形貌,油水比为10～20时,微球的粒径随油水比的增大而减小.实验结果很好地吻合了模拟结果.     

淀粉乳液形成过程主要影响因素的耗散粒子动力学模拟与实验

以环己烷为油相、淀粉乳液为水相、Span60和Tween60为乳化剂, 用耗散粒子动力学(DPD)方法研究了淀粉乳液形成过程及油水比、乳化剂用量等因素对淀粉乳液形成的影响. 结果表明, 模拟6000步时, 体系达到平衡状态; 乳滴的粒径随乳化剂含量的增加先减小而后增加, 随淀粉含量的增加而增加, 随环己烷含量的减小而增加; 形成稳定淀粉乳液体系的参数范围: 7＜油水比≤20, 9%＜乳化剂用量≤18%. 实验结果表明, 乳化剂含量为11%～15%时, 微球的粒径随乳化剂含量的增大而减小; 乳化剂含量大于15%时, 微球的粒径反而增大. 实验与模拟的结果吻合.     

油醇聚氧乙烯醚类化合物在D相乳化技术中的研究

以甘油(通用保湿剂)水溶液为水相,太阳花油为油相,油醇聚醚-10、20、30为乳化剂进行D相乳化探究,并绘制出相应相图。结果表明油醇聚醚-10在该条件下并不能实现D相乳化,而油醇聚醚-20与油醇聚醚-30在一定范围内可以顺利实现D相乳化;该组合对常见天然植物油脂也能得到相同结果。通过与普通乳化方法进行对比实验,发现以太阳花油作为油相,甘油水溶液作为水相,油醇聚醚-30作为乳化剂,通过D相乳化技术可以制备乳液粒径分布均匀且微细的乳液(d=1～4μm),而且能量需求更小。进一步的实验发现,多元醇对D相乳化过程中乳化剂的亲水亲油平衡性起着两向调节作用,这与其对相应非离子乳化剂的浊点升高或降低作用密切相关。     

精制废木屑热解油/柴油新型混合燃料制备实验研究

为提高废木屑热解油品质,使其能够作为发动机燃料使用,提出了一条新的热解油提质路线。首先将热解原油进行基于组分分离的乙醚萃取和化学催化相结合的精制过程,得到精制热解油;其次,利用超声反应器制备了精制热解油/柴油新型混合燃料,以单位体积柴油所溶解的精制油的体积定为S值,作为判断乳化效果的准则,考察了不同的影响因素对S值的影响。研究结果表明,乳化剂添加量对S值影响较大,在V_{精制生物油}:V_柴油:V_乳化剂=10:30:5条件下,存在最佳的乳化超声操作条件:超声时间、超声电功率、乳化温度分别为20 min、540 W、50℃。制备了不同S值的乳化燃料,通过对燃料物理指标的分析发现,该燃料性质稳定、燃烧性能优良,有望成为柴油的替代产品。     

基于广义阴阳表面活性剂体系对不同黏度区间原油的普适性降黏作用

采用脂肪酸-脂肪胺混合的广义阴阳体系,分别通过水相引入与油相引入两种方式对黏度分布在0.05-155 Pa?s范围内的4种原油进行乳化降黏。针对不同地区原油的组成特点与黏度成因,调整复配体系中脂肪酸-脂肪胺的分子结构,采用不同手段构筑乳状液:对于黏度较低的普通稠油,采用水相引入脂肪酸-脂肪胺复配体系的方法;而对于胶质、沥青质含量极高的超稠油,采用油相引入脂肪酸-脂肪胺复配体系黏的方法。两种方法的降黏率均达到95%-99%,获得较为理想的降黏效果。     

离心法测定乳化液中不安定相含量

在金属加工过程中 ,乳化切削油是目前使用最广泛的一种切削液。乳化切削油由矿物型基础油、表面活性剂、极压润滑剂、防锈剂、杀菌剂等组成 ,使用时用水稀释成 2 % 10 %的溶液 ,稀释液为乳白色。乳化油是依靠其中的表面活性剂降低油、水界面的表面张力 ,形成稳定的水包油乳化体系 ,好的乳化液应具有良好的乳化安定性 ,即油均匀分散在水中 ,不析出油或皂 ,这样的乳化液才能在机械加工中发挥稳定的作用。在乳化油的行业标准SH/T 0 36 5 -1992中 ,规定了乳化液安定性试验方法 ,即将 5 %乳化液 5 0ml置于 5 0ml滴定管中 ,放置 2 4h后观察皂或…     

复合改性聚丙烯酸酯柴油低温流动改进剂

合成了改性聚丙烯酸高级酯(PADE)和一种新的蜡晶分散剂3,6-氧桥-1,2,3,6-四氢苯-1,2-二甲酸高级酯/酰胺(EBTD),测试了对0#柴油的低温流动性能的改进效果。结果表明,PADE对蜡晶具有较好的分散作用,能有效地降低燕山、大连、辽河0#柴油的冷滤点,冷滤点降幅为7~10℃;对大庆0#柴油的感受性也较显著,与EBTD复合有增效作用,二者复配后能较好的改善大庆0#柴油的低温流动性能,可以使大庆0#柴油冷滤点降低7~8℃。     

高效有机硅消泡剂的研制与应用

以二甲基硅油、疏水气相二氧化硅制成的硅膏和聚醚改性硅油为主要成份,Span-60、Twen-60为乳化剂,采用高速剪切乳化搅拌方式将水相在油相中进行乳化,制备出高效乳液型有机硅消泡剂。研究了各主要成分的含量及乳化温度对消泡剂性能的影响,得到的最佳配方为:硅膏的质量分数分别为12%,聚醚改性硅油4%,HLB值为9.5的复配乳化剂6%。制备的有机硅消泡剂的稳定性及消泡抑泡性能较好,适用范围广。     

柴油-生物质油乳化燃料最佳HLB值及理化性质研究

采用超声波乳化法制备柴油-生物质油乳化燃料,并研究了乳化燃料所需乳化剂的最佳亲水亲油平衡（HLB）值以及乳化条件对乳化燃料稳定性的影响,测定了乳化燃料的密度、黏度、闭口闪点、烟点、凝点和总热值等理化性质。结果表明,柴油-生物质油乳化燃料乳化剂的最佳HLB值为5.5~6.2;当乳化温度为50℃~60℃、单位容积输入功为180J/mL~300J/mL时,乳化燃料的稳定性最好;乳化燃料的密度、黏度、闪点和烟点随生物质油比例的增加而增大,而凝点和总热值则随生物质油比例的增加而降低。     

Influence of the deacetylation degree on chitosan emulsification properties

The emulsification of sunflower oil by chitosan solutions with deacetylation degrees (DD) between 73 and 95% was studied using different techniques. The droplet size distributions, conductivity, ageing behavior and viscosity of emulsions were studied as functions of the chitosan DD. All DD gave stable polydisperse water-in-oil-in-water emulsions with different viscosities. Two optimum DD values were found, 81 and 88%, giving complete emulsification without residual oil or sedimentation. Chitosans with intermediate DD were less effective emulsifiers. Chitosans with higher DD gave poor emulsification. Received: 11 January 1999 Accepted in revised form: 31 May 1999     

Valorisation of bio-oil resulting from fast pyrolysis of wood

Bio-oil resulting from the pyrolysis of lignocellulose is a complex mixture of polar low molecular mass oxygenated compounds of various functionalities and non-polar high molecular mass lignin derivatives. Several approaches to the upgrading of bio-oil are currently in progress. This study investigates the valorisation of crude bio-oil using physical and chemical methods. The effects of methanol addition on some properties of the bio-oil are investigated. Stable bio-oil/diesel oil emulsions are produced by the addition of surfactants with a hydrophilic-lipophilic balance value of 5–6. An alternative approach towards the upgrading of bio-oil is the hydrotreatment of the water-soluble fraction of bio-oil. Two-stage hydroprocessing with noble-metal catalysts Ru/C and Pt/C increases the intrinsic hydrogen content of the water-soluble fraction. The results show that the thermally unstable components including sugars, ketones and aldehydes are readily converted to diols and alcohols at pressures of 5 MPa. These observations can be explained by a set of reaction pathways for the compounds identified.     

Rheological behavior of aqueous organosilicone resin emulsion stabilized by colloidal nanosilica particles

Inorganic colloidal particles were usually used to stabilize the emulsions of small molecular compounds. In this paper, the stable aqueous emulsions of organosilicone resin were prepared by emulsification technique using colloidal nanosilica particles combined with very small amount of emulsifiers. The effects of the silica size and concentration on the rheological behavior of the emulsion were investigated by steady-state and transient rheological measurements and dynamic modulus measurement. It was found that all emulsions containing colloidal silica particles exhibited shear-thinning behavior. The smaller the colloidal silica size was or the more the silica content was, the greater the storage modulus was at low strain amplitude, indicating a stronger interparticle interaction and a solidlike viscoelastic behavior of the emulsion. This rheological behavior can be explained by the formation of the reversible particulate network in the emulsion.     

Multivariate optimization of the determination of zinc in diesel oil employing a novel extraction strategy based on emulsion breaking

This paper describes the extraction/pre-concentration of Zn from diesel oil and its determination by Flame Atomic Absorption Spectrometry (FAAS), proposed as a novel approach for these kinds of analyses and the multivariate optimization of the proposed procedure. The extraction of Zn is based on the emulsification of an aqueous solution containing Triton X-114 and HNO₃ with diesel oil samples followed by breaking of the emulsion by heating. The aqueous phase obtained after the emulsion breaking was collected and used for Zn quantification by FAAS. The methodology was optimized using a Doehlert design and the system variables were the concentrations of surfactant and HNO₃ in the solution employed in the emulsification and the temperature used in the emulsion breaking. The ratio between absorbance and the time required to break the emulsions was taken as response. Two sets of experiments, using different emulsifier agents, were run: the first one using Triton X-100 and the second one using Triton X-114. At optimized conditions, the emulsions were prepared by mixing 10 mL of diesel oil with 2 mL of a solution containing 5% w/v of Triton X-114 and 15% v/v of HNO₃ and broken by heating at 80 °C. The proposed analytical procedure was applied in the analysis of six real samples of diesel oil and a recovery test was carried out by spiking the samples with known amounts of Zn (25 and 50 μg L⁻¹), added as organometallic oiled standard. Recovery percentages achieved in this test were between 92 and 109%.     

Encapsulation and Prolonged Release Behaviour of W/O/W Type Multiple Emulsions

W/O/W type multiple emulsions were prepared by two step emulsification procedures using an oily lymphographic agent, lipiodol, as an inner oil phase and Pluronic F-68 as a hydrophilic emulsifier contained in the outer aqueous phase. Span 80, Pluronic L-64 and HCO-60 were used as emulsifiers incorporating them into the inner oil phase. The phase volume of the inner and outer aqueous phases and the yield of the w/o/w type multiple emulsions were studied. The dissolution behaviour of the w/o/w type multiple emulsions were determined by a dialysis method employing cellulose tubing. The effect of emulsifier type and the amount of HCO-60 on the stability and prolonged release behavior of the w/o/w type multiple emulsions with or without lecithin, was also examined. The results indicate the HCO-60 is a better emulsifier than Span 80 or Pluronic L-64. Its use improves the stability and the prolonged release behavior of w/o/w type multiple emulsions.     

Quantification of unadsorbed protein and surfactant emulsifiers in oil-in-water emulsions

Unadsorbed emulsifiers affect the physical and chemical behaviour of oil-in-water (O/W) emulsions. A simple methodology to quantify unadsorbed emulsifiers in the aqueous phase of O/W emulsions has been developed. Emulsions were centrifuged and filtered to separate the aqueous phase from the oil droplets and the concentration of unadsorbed emulsifiers in the aqueous phase determined. The quantification of unadsorbed surfactants based on the direct transesterification of their fatty acids was validated for Tween 20, Tween 80, citric acid ester (Citrem), Span 20 and monolauroyl glycerol. To determine unadsorbed proteins, results obtained with Folin-Ciocalteu reagent or UV-spectrophotometry were compared on emulsions stabilized by β-lactoglobulin (BLG), β-casein (BCN) or bovine serum albumin (BSA). The first method gave more accurate results especially during aging of emulsions in oxidative conditions. The whole methodology was applied to emulsions stabilized with single or mixed emulsifiers. This approach enables optimization of emulsion formulations and could be useful to follow changes in the levels of unadsorbed emulsifiers during physical or chemical aging processes.     

Thickening properties and emulsification mechanisms of new derivatives of polysaccharides in aqueous solution

The thickening properties of aqueous solutions of HHM-HEC (hydrophobically-hydrophilically modified hydroxyethylcellulose) and the emulsification mechanisms of HHM-HEC/water/oil systems were investigated. A dramatic increase in viscosity was observed with increased HHM-HEC concentration in water, caused by aggregation of hydrophobic alkyl chains. At higher concentrations of HHM-HEC (above 0.6 wt%) in water, it forms an elastic gel, which has good thixotropic properties and a high yield value. O/W (oil-in-water) type emulsions were obtained using HHM-HEC, which can emulsify various kinds of oil, including hydrocarbon, silicone, and perfluoropolymethylisopropyl ether. The viscosity of these emulsions depends only upon the oil volume fraction, not on the kind of oil. In addition, the oil particle size in the emulsions remained constant after a certain period because HHM-HEC formed a strong gel network structure and a protective layer, which prevented the emulsion from coalescing. Measurements of interfacial tension revealed that the alkyl chains in HHM-HEC did not significantly lower the interfacial tension at the water/oil interface when 0.5 wt% of HHM-HEC was added to water. Steady flow and oscillatory experimental results show that the rheological behavior of HHM-HEC/water/oil emulsions was similar to that of aqueous solutions of HHM-HEC. In the HHM-HEC/water/oil emulsion system, oil droplets were dispersed and kept stable in the strong gel structure of HHM-HEC. The aqueous solution of HHM-HEC showed salt resistance. It is thought to be due to sulfonic acid groups in HHM-HEC. The stability of the emulsion using HHM-HEC is based on both protective colloidal effects and associative thickening caused by alkyl chains in HHM-HEC.     

Efficient emulsification of viscous oils at high drop volume fraction

It is shown experimentally in this study that the increase of drop volume fraction can be used as an efficient tool for emulsification of viscous oils in turbulent flow. In a systematic series of experiments, the effects of drop volume fraction and viscosity of the dispersed phase on the mean, d(32), and maximum, d(V95), diameters of the drops, formed during emulsification, are quantified. The volume fraction, Φ, of the dispersed oily phase is varied between 1% and 90%, and oils with viscosity varying between 3 and 10,000 mPa.s are studied. All experiments are performed at sufficiently high surfactant concentration, as to avoid possible drop-drop coalescence during emulsification. The analysis of the experimental data shows that there is a threshold drop volume fraction, Φ(TR), at which a transition from inertial turbulent regime into viscous turbulent regime of emulsification occurs, due to the increased overall viscosity of the emulsion. At Φ < Φ(TR), d(32) and d(V95) depend weakly on Φ and are well described by known theoretical expression for emulsification in inertial turbulent regime (Davies, Chem. Eng. Sci. 1985, 40, 839), which accounts for the effects of oil viscosity and interfacial tension. At Φ > Φ(TR), both d(32) and polydispersity of the formed emulsions decrease very significantly with the increase of Φ (for the oils with η(D) > 10 mPa.s). Thus, very efficient emulsification of the viscous oils is realized. Very surprisingly, a third regime of emulsification is observed in the range of concentrated emulsions with Φ > 75%, where the mean drop size and emulsion polydispersity are found experimentally to be very similar for all oils and surfactants studied-an experimental fact that does not comply with any of the existing models of drop breakup during emulsification. Possible mechanistic explanations of this result are discussed. The experimental data for semiconcentrated and concentrated emulsions with Φ > Φ(TR) are described by a simple scaling expression, which accounts for the effects of all main factors studied.     

Supramolecular Polymer Emulsifiers for One-step Complex Emulsions

Complex emulsions,such as double emulsions and high-internal-phase emulsions,have shown great applications in the fields of drug delivery,sensing,catalysis,oil-water separation and self-healing materials.Their controllable preparation is at the forefront of interface and material science.Surfactants and polymers have been widely used as emulsifiers for building complex emulsions.Yet some inherent disadvantages exist including multi-step emulsifications and low production efficiency.Alternatively,supramolecular polymer emulsifier for complex emulsions via one-step emulsification is rising as a new strategy due to the ease of preparation.In this feature article,we review our recent progresses in using supramolecular polymer emulsifiers for the preparation of complex emulsions.Double emulsions and high-internal-phase emulsions are successfully prepared via one-step emulsification with the help of different supramolecular interactions including electrostatic,hydrogen bond,coordination interaction and dynamic covalent bond,which will be particularly emphasized in detail.In the end,a comprehensive prospect is given for the future development of this field.This article is expected to provide new inspirations for preparing complex emulsions via supramolecular routes.