辽河油田稠油O/W乳状液的破乳实验

实验考察了TA-1、TA-3、BP-6、SP-1,SP-2、AE-3、TG-1、THO-A2、THG-A3等12种商用破乳剂对辽河油田稠油乳状液的破乳效果,并考察了破乳剂的复配破乳效果.结果表明:THG-A2、TA-1两种破乳剂破乳120 min后,稠油乳状液脱水率可以达到80%;THG-A2/SP-2在复配质量比1:2、投放量为0.3～0.35 g/L、破乳温度为60～65℃时复配处理效果最佳,采用该复配剂破乳120 min后,脱水率可高达98.7%.此外,本文通过高速摄像观察了稠油乳状液的破乳过程,并对其破乳机理进行了分析.     

W／O型乳状液破乳技术进展

介绍了近年来W／O型乳状液的破乳技术,包括重力法、离心法、加热法、化学法、电学法、微波辐射法、超声波法、膜法、微生物法、磁处理法、冷冻解冻法、研磨法、润湿聚结法以及针对于沥青质薄膜决定稳定性的W／O型稠油乳化液的新型CO2破乳法,归纳了各种方法的破乳机理和研究现状,并概述了各种技术的应用特点,为其工业应用提供参考。     

石油醚W/O乳状液及其液膜稳定性

以破乳率为衡量标准,借助显微镜直接观察,探讨了乳状液含水量、表面活性剂用量、乳化时间、乳化强度等因素对石油醚W/O型乳状液体系稳定性的影响。在实验范围内,乳状液含水量的提高及表面活性剂用量的增加,有利于乳状液的稳定;存在较优的乳化时间20min和乳化强度4000rmin-1。选取脂肪烃、芳香烃、混合烃共6种不同油相制备乳状液,对比其稳定性的差异。此外,还初步考察了石油醚W/O/W液膜溶胀和泄漏问题,结果表明该乳状液膜泄漏率低于3.5%,表观溶胀率约为20%。     

冷冻解冻法破除液体石蜡W/O乳状液

冷冻解冻法是一种新型的破除W/O乳状液的物理破乳方法.为了揭示冷冻解冻破乳作用机制,本文以稳定性好的液体石蜡W/O乳状液为研究对象,采用差热扫描量热仪（DSC）与显微镜,研究了高黏度连续相液体石蜡体系的W/O乳状液的冷冻解冻破乳过程.结果表明：该破乳过程是一个渐进过程.当乳珠粒径均匀细小,小于5.5 μm时,乳珠在冷冻解冻循环中逐渐长大,经多次冷冻解冻后完成破乳;然而当乳珠粒径较大时,如51 μm,乳状液体系仅需单次冷冻解冻循环就可破乳较完全,破乳率超过90%.此外,乳状液含水量的增加有利于提高破乳效率.乳状液水相的凝固点受乳珠尺度的影响,但受含水量的影响不显著.当乳珠粒径较大时,水相凝固点随乳珠粒径的减小而降低;但是当乳珠粒径降至5.5 μm时,乳珠粒径的改变对其影响已不明显.     

陶瓷膜乳化法制备O/W乳状液

膜乳化法是获得高质量单分散稳定乳状液的一种简单有效方法,以氧化铝陶瓷微滤膜为乳化媒介,大豆油为分散相,含有乳化剂的去离子水为连续相,直接制备O/W乳液.比较了膜乳化法与机械搅拌法的乳化效果;考察了乳化剂浓度、膜两侧压差和磁力搅拌转速对乳化效果的影响.结果表明:乳化剂浓度2%、膜面压差0.12MPa、搅拌转速450r/min为最佳乳化条件.     

油包水型原油乳状液破乳技术研究进展

阐述了化学法、生物法、物理法等油包水型原油乳状液破乳技术,从工艺机理、影响因素、优缺点等各方面对技术进行了综述,分析与总结了技术发展现状,并对各种破乳技术进行了概括和比较,就破乳技术发展前景进行了展望,以期为破乳技术改进、优化和提效提供参考。     

驱油剂对W/O乳状液稳定性影响研究

利用TURBISCAN稳定性分析仪测得的TSI值监测了驱油剂对W/O乳状液稳定性的影响,实验结果表明,随着表面活性剂和聚合物浓度的增加,TSI值均降低,乳状液稳定性增加;随着碱浓度的增大,TSI值先降低后增大,体系稳定性先增强后变弱,当碱浓度为900mg/L时,乳状液稳定性最好。     

稠油O/W型乳状液微观现象研究

新滩稠油O/W乳状液是由含水较高的W/O乳状液直接转相形成的,利用微观摄像技术对其微观结构进行了研究。研究发现,乳状液中含有一定量的W/O/W液滴,其数量的多少与乳化剂浓度和含水量的大小有一定关系。液滴的形状大多数是等轴球形,既有液滴单个的乳滴存在,又有相互接触的乳滴簇存在,有乳滴形成乳滴簇的过程,也有乳滴簇分离的过程。乳滴大小分布模式基本相似,但对于具体的乳状液来说还是有差别。乳滴的大小分布受乳化剂浓度、油水性质含水量和放置时间等的影响。乳状液随时间表现出的性质主要是其微观结构变化的结果。液滴的大小分布情况和存在方式,在一定程度上影响乳状液的稳定性和流变行为。     

油水乳状液破乳技术研究进展

重点介绍了近年来乳状液破乳技术在破乳方法、破乳效果影响因素、破乳剂的开发等方面的研究进展,并分析总结了破乳技术研究存在的不足,提出了破乳技术研究的努力方向。     

疏水缔合三元共聚物破乳剂的合成及破乳性能评价

以AM/BM/DMC为单体(质量配比为1:0.04:1,单体总质量浓度35%),采用水溶液聚合法,引发剂加量1%,反应温度25℃,反应时间4 h,合成了AM-BM-DMC疏水缔合三元共聚物破乳剂,对其在不同浓度、不同温度、不同时间下的破乳性能进行评价。结果表明,通过水溶液聚合方法合成的疏水缔合三元共聚物破乳剂在常温(25℃)下,对O/W型乳状液具有较好的破乳能力,脱出水色清,脱水速度快,脱水率高,可达90.8%。其破乳的温度范围为20～40℃,无需加热设备,适合于现场应用,是一种具有潜力的新型破乳剂。     

一体式陶瓷外膜直接乳化法制备单分散水包油乳液

膜乳化法是靠膜两侧的压差使分散相通过微孔膜,以小液滴的形式分散在连续相中而形成乳状液的方法．与转一定体系、高压均化等传统制乳方法相比,膜乳化法所制得的乳液具有液滴尺寸均一、节能、剪应力小等特点,可应用于食品、医药、聚合物工业等领域．过去的十几年中,尽管在膜乳化方面进行了大量的工作,过程参数对乳滴尺寸的影响并未完全研究清楚．甚至在一些研究中,仅仅把平均乳滴直径作为分布参数．     

Effect of sunflower lecithins on the stability of water-in-oil and oil-in-water emulsions

Lecithins are frequently applied in the food industry as emulsifiers, viscosity regulators, and dispersing agents. The main aim of the present work was to study the emulsifying capability of diverse sunflower lecithins so as to evaluate the functionality of these by-products, which are not extensively used at present. The experimental results obtained for water-in-oil (W/O) emulsions showe that dispersions containing levels of 0.1% lecithins were more stable against coalescence than a control system, whereas those with 1% emulsifying agent exhibited the opposite behavior. On the other hand, faster sedimentation kinetics were observed at a concentration of 0.1% than at 1%. Lecithins with high phospholipid content, especially phosphatidylethanolamine and phosphatidylinositol, were found to be the best emulsifying agents for W/O dispersions. In the case of oil-in-water emulsions, it was possible to observe two processes: creaming of emulsions with the addition of 1% of lecithins, and instant creaming followed by coalescence of the cream phase in those cases corresponding to 0.1% added lecithin.     

Novel extensional device to efficiently form fine oil-in-water food emulsions

Two immiscible liquids are commonly mixed by mechanically dispersing one into the other to form emulsions. Surfactants or emulsifiers confer stability. Mechanical mixing, in practice, is an energy-intensive shear flow that is ineffective when the ratio of the dispersed-phase viscosity to the continuous-phase viscosity exceeds about four. Extensional flows are not subject to this viscosity ratio limit. This superiority of extensional flow was exploited to fabricate a novel, continuous-flow, cone-shaped device with an extensional strain of eight to make fine soybean oil-in-water emulsions. A spherical insert having a wall clearance of 25 μm was an effective design factor. Starting with ‘coarse’ 50 wt.% oil emulsions, two stretching episodes were needed for size reduction. The temperature rise was negligible, and the results were independent of the emulsifier type employed. Increasing flow rate and stretching episodes, reducing wall clearance, enhancing emulsifier concentration, and multiple passes through the device gave progressively smaller drops; the volume-averaged diameter became less than 2 μm, and the number-averaged diameter reached 0.5 μm, narrowing the size distribution. The emulsions that formed had a high viscosity and were stable. The performance of a scaled-up device was compared with other mixers. At equivalent energy density and 50 wt.% oil, drop sizes were similar for a valve homogenizer but larger for a rotor-stator mixer. At 80 wt.% oil, the rotor stator-mixer again required more energy for the same drop size, but emulsions prepared with the valve homogenizer broke. The findings of this study can help to design industrial-scale energy-efficient extensional-flow dominant devices for the formation of food emulsions.     

Emulsifying properties and surface behavior of native and denatured whey soy proteins in comparison with other proteins. Creaming stability of oil-in-water emulsions

In this work a comparative study of emulsifying and surface behaviors of native whey soy proteins (NWSP) and denatured whey soy proteins (DWSP) with those of native soy isolates, denatured soy isolates (DSI), and sodium caseinate was done. These samples showed different molecular mass distributions in gel filtration profiles. Dissociation and soluble high-M.W. species in DWSP and DSI were observed. Lower interfacial and surface pressure values were obtained with native samples. Thermal treatment and salt addition enhanced tensioactivity in all fractions. Backscattering measurements of all oil-in-water emulsions, which exhibited a trimodal size distribution of droplets, showed the existence of a negative correlation with the median diameter of droplets. Greater droplet sizes were observed with NaCl addition. The NWSP emulsion had the lowest stability against creaming. Denaturation of this sample increased stability and favored air incorporation in emulsions. Destabilization depends not only on median droplet size but also on floc formation and structure. NaCl addition negatively affected the creaming stability only in emulsions formulated with soy isolates. The use of denaturation to enhance the surface and emulsifying properties of whey soy proteins would allow their use in food emulsions.     

Styrene polymerized in an oil-in-water microemulsion

Microemulsions of styrene dispersed in water using sodium dodecyl sulphate and pentanol and polystyrene, isolated after the polymerizations were carried out to completion, were studied by photon correlation spectroscopy and time-averaged intensity measurements. Microemulsions contained droplets 40.8 nm in diameter. It was found that the size distributions of polystyrene were bimodal. The results indicate that smaller droplets in a microemulsion provide an increased surface area which can complete with micelles in the capture of radicals. The bimodal nature of the products is evidence for two mechanisms of initiation and particle growth.     

CONCENTRATED VISCOUS CRUDE OIL-IN-WATER EMULSIONS FOR PIPELINE TRANSPORT

The need to utilize viscous crude oils will increase in the next decade. One means to facilitate pumping of heavy crudes in pipelines is to transport them as concentrated oil-in-water emulsions. Stable emulsions could be prepared by alkali treatment with four of seven viscous crudes studied. Surfactants are formed by reaction of natural acids in the crude with alkali. At crude volume fractions of 60%, emulsion apparent viscosity was lowered as much as 10,000 times.

Viscosities of crude emulsions formed by alkali treatment varied with the nature of the crude and with the ratio of base added to the TAN of the crude. Emulsion viscosities and particle diameters reach extrema close to the equivalence point.

The addition of tall oil enhanced the emulsification ability of some of the crudes with alkali treatment, but one crude required non-ionic surfactant to form an emulsion.     

Argan oil-in-water emulsions: Preparation and stabilization

We prepared stable oil-in-water emulsions of argan oil with two different types of mixtures of nonionic emulsifiers. Three different types of oil (Israeli argan oil, Moroccan argan oil, and soybean oil) were emulsified with mixtures of Span 80 and Tween 80. The optimum HLB value for argon oil was 11.0 (±1.0). The argan oil-in-water emulsions were stable for more than 5 mon at 25°C. Synergistic effects were found in enhancing stability of emulsions prepared with sucrose monostearate. The origin of the oil and the internal content of natural emulsifiers, such as monoglycerides and phospholipids, have a profound influence on its interfacial properties and on the stability of the argan oil-in-water emulsions.     

Preparation of micron-scale monodisperse oil-in-water microspheres by microchannel emulsification

Micron-scale monodisperse oil-in-water (O/W) micropheres (MS) were prepared using a novel microchannel (MC) emulsification technique. The characteristics of the MS preparation and the O/W-MS prepared were studied. Soybean oil and medium-chain triacyglycerol (MCT) were used as the disprrsed phase, and physiological saline was used as the continuous phase. Silicon MC with 1 to 3μm-equivalent channel diameters were employed. A novel MC module was devised to easily recover the O/W-MS prepared. The effects of the channel shape on the behavior of MS formation, on the MS size, and on the distribution were investigated. An MC with a terrace at the MC outlet stably yielded micron-scale monodisperse O/W-MS; the MS had diameters of about 5 μm, and their coefficients of variation were below 9%. Monodisperse food-grade O/W-MS with diameters of about 4 μm could be obtained by using polyglycerol fatty acid ester as the surfactant. The size and size distribution of the recovered O/W-MS remained almost constant over 60 d, demonstrating their long-term stability.     

Fibrous ceramic membrane constructed by mullite whiskers for the treatment of oil-in-water emulsions

Ceramic membranes with high porosity and excellent separation efficiency are necessary for the efficient treatment of large-scale wastewaters. However, the conventional ceramic membranes are usually prepared by particles-packing, which inhibits the advances of separation efficiency because of the low porosity and connectivity. Here, a fibrous ceramic membrane with mullite whiskers-interlocked structure was prepared by gas-solid reaction. The effects of aluminum fluoride (AlF₃) on the formation and growth of mullite whiskers, and then the permeability and selectivity of the ceramic membranes were investigated. With the increase of AlF₃ contents, the mullite phase evolved from needle-like, rod-like to flake-like structure, thus the catalyst accelerated the growth of mullite whiskers in the diameter direction. For the ceramic membrane sintered at 1400°C, the porosity increased from 58% to 76% while the average pore sizes increased from 0.65 to 3.93 μm because of the whisker-constructed structures. For the ceramic membrane sintered at 1450°C, the emulsion flux increased stably from 295 L/(m²·h) to 992 L/(m²·h) with the increase of trans-membrane pressure, and the oil rejection exceeded 98%. Thus, this study provides a feasible strategy for the preparation of ceramic membranes with high porosity and excellent separation performances.     

用燃烧裂解法处理甲醇废水

湖南金信公司有6.0×104t/a的甲醇生产装置,采用联醇工艺生产,生产过程中排出近300 kg/t的甲醇废水,若产生的甲醇废水直接排放,会严重污染环境.根据该公司的实际情况,采用燃烧裂解法,利用固定层煤气发生炉回收处理甲醇废水,不仅可以回收利用软水,降低煤耗,而且可以取得显著的环保效益.经实施后运行表明,采用燃烧裂解法处理甲醇废水.节约造气炉夹套锅炉软水消耗39 600 t/a,经济效益为14.2万元/a,经济效益显著.