以Span80为乳化剂制备煤油包水乳状液的实验研究

为了制备能够模拟乳状液膜分离过程中使用的模型乳状液,以Span80作为乳化剂利用高速搅拌乳化法制备了含有内水相化合物的煤油包水乳状液.考察了内水相化合物种类及浓度、搅拌转速、搅拌时间、乳化剂浓度、含水率等因素对乳状液的静置沉降稳定性的影响,同时确定了内水相化合物为Na OH时乳状液的相转变点.实验结果表明:以Na OH作为内水相化合物时,最佳乳化条件为:Na OH浓度0.25 mol·L-1,Span80浓度3 g·L-1,含水率45%,搅拌转速14000 rpm,搅拌时间2 min,所得乳状液在2 h内的静置沉降稳定性可达88%以上;控制其他条件不变,当Na OH浓度为0.25 mol·L-1时,相应的其相转变点含水率为55%,而当Na OH浓度为下降到0.02 mol·L-1时,相应的其相转变点含水率变为45%;增加乳化剂浓度,提高搅拌转速,增加搅拌时间,降低Na OH浓度有利于增强乳状液的稳定性.

Effects of Different Heavy Crude Oil Fractions on the Stability of Oil-in-water Emulsions —— Isolation of functional fractions from heavy crude oil and study of their properties

The functional fractions (acid, basic, amphoteric and neutral fractions) are isolated from the Liaohe Du-84 heavy crude oil and Shengli Gudao Kenxi heavy crude oil by ion-exchange chromatography, but the conventional fractions (saturates, aromatics, resins and asphaltenes) are also isolated from the heavy crude oil. These components have been characterized by spectroscopic methods (FT-IR), namely acid number, basic nitrogen number, ultimate analysis and molecular weight measurements using vapor pressure osmometry (VPO). The ion-exchange chromatography method based on separation by a functional group induces a little change on the nature of the crudes and reasonable mass balances can be easily obtained.

Experimental measurements of water content in crude oil emulsions by terahertz time-domain spectroscopy

We measured the water content （0.01% 0.25% w/w） in crude oil emulsions using terahertz time-domain spectroscopy （THz-TDS）. To improve the precision and range of the measurements, we used 1 and 10 mm thick quartz cells. The experiments were performed at 20 ℃ and the THz wave was transmitted vertically to the samples and detected on the other side. The experimental results suggest linear relation for the THz absorption coefficient and the water content of the crude oil emulsions in the observed range. The linear dependence facilitates high-precision measurements of the water content of crude oil. This suggests the potential of THz-TDS in determining the water concentration in crude oil and borehole fluid identification.

Measurement of water holdup in oil-in-water emulsions in wellbores using microwave resonance sensor

In this study,we propose a new method for water holdup measurement of oil-in-water emulsions with a microwave resonance sensor(MRS).The angle and length of the electrode plate are optimized by HFSS simulation software.Using a vector network analyzer(VNA),a static calibration experiment is conducted,and the resonant frequency distribution of oil-in-water emulsions is analyzed within an 80%–100%water holdup range.In addition,we observe and analyze the micron-sized oil bubble structure in the emulsifi ed state with an optical microscope.On this basis,a dynamic experiment of oil-in-water emulsions with high water cut and low velocity in a vertical upward pipe is conducted.S_(21) response curves of the MRS are obtained by the VNA under diff erent working conditions in real time.Finally,we analyze the relationship between the resonant frequency and water cut.Experimental results show that the MRS has an average resolution of 0.096%water cut for high water cut oil-in-water emulsions within the frequency range of 2.2–2.8 GHz.

Kinetic and Phase Behaviors of Catalytic Cracking Dry Gas Hydrate in Water-in-Oil Emulsion

The systematic experimental studies were performed on the hydrate formation kinetics and gas-hydrate equilibrium for a simulated catalytic cracking gas in the water-in-oil emulsion. The effect of temperature, pressure and initial gas-liquid ratio on the hydrate formation was studied, respectively. The data were obtained at pressures ranging from 3.5 to 5 MPa and temperatur.es from 274.15 to 277.15 K. The results showed that hydrogen and methane can be separated Irom the （~2＋ ti＇action by tOrming hydrate at around 273.15 K which is much higher temperature than that of the cryogenic separation method, and the hydrate formation rate can be enhanced in the wa- ter-in-oil emulsion compared to pure water. The experiments provided the basic data for designing the industrial process, and setting the suitable operational conditions. The measured data ot gas-hydrate equilibria were compared with the predictions by using the Chen-Guo hydrate thermodynamic model.

Study of Oil/Water Interfacial Tension of Vacuum Residual Fractions from Iranian Light Crude Oil

The vacuum residual from Iranian Light crude oil are separated into a series of 16 narrow fractions according to the molecular weight by the supercritical fluid extraction and fractional (SFEF) technology. The chemical element and the UV spectrum of each fraction are analyzed. The effects of several factors on the interfacial tension are investigated, which are the fraction concentration in oil phase, the ratio of oil component, the salts dissolved in the water phase and the pH value. The interfacial tension decreases rapidly as the concentration of the residual fraction in the oil increases, showing a higher interfacial activity of the fraction. The interfacial tension changes, as the amount of absorption or the state of the fractions in the interface changes resulting from different ratios of oil, different kinds or concentrations of salts in water, and different pH values. It is concluded that the interfacial tension changes regularly, corresponding to the regular molecular parameters of the vacuum residual fractions.

Demulsification of Emulsion Liquid Membrane by Wetting Coalescence Materials

Demulsification of emulsified water-in-oil droplets was worked out with the employment of wetting coalescence materials. Demulsification is carried out in conventional stirred-column and packed-column. Among the four kinds of natural fibers and two kinds of inorganic materials tested, natural fiber A, originated from wood shavings was found to give the best performance of demulsification. The demulsification efficiency can exceed 96.5% when demulsification conditions are optimized. The packed-column showed much better performance both in terms of demulsification efficiency and repeated use of the recovered oil phase for extracting cadmium in simulated wastewater. Operating variables governing the demulsification efficiency were investigated.

An Osmotic Pressure Equation of Uncharged Micelle and Oil/Water Microemulsion Systems

1 INTRODUCTIONMicroemulsion and micelle systems are wide-spread in the industry and agriculture applications,e.g.the petroleum exploitation,food industry chemical engineering and biological engineering,but so far,their properties are still not very well understood.Both micelle and microemulsion systems are dispersed systems and consist of the aggregationsof the surfactant.The difference between them is that there is dispered liquid phase in the coreof the aggregation in the case of the microemulsion,but in the micelle there is not any

Kinetics for Describing the Creaming of Protein-Stabilized O/W Emulsions by Multiple Light Scattering

In the present work, new kinetics to describe the creaming stability of oil-in-water emulsions determined by backscattering measurements （BS） is proposed. The emulsions assayed exhibited a different backscattering profiles regarding creaming destabilization hyperbolic and sigmoid one. Hyperbolic behavior can be described by a second order kinetics, where k_h could be equaled to a rate constant that describes the creaming process and its values would indicate the stability of emulsions. While for the sigmoid BS pattern, kinetics with two terms, is adequate to describe the creaming process in contrast to kinetics previously reported in the literature. The kh value has the same meaning as before, and ks indicates the delaying effect on the creaming rate.