Dynamic Interfacial Tension between Crude Oil and Dodecylmethylnaphthalene Sulfonate Surfactant Flooding Systems

Abstract

The surface tension of surfactant aqueous solutions and dynamic interfacial tensions (DIT) between crude oil, offered from Shengli Oil Field in China, and surfactant flooding systems, and the single-component dodecylmethylnaphthalene sulfonate (DMNS) surfactant, developed in our laboratory, were measured. In the present report, both buffered alkali and no alkali flooding systems were investigated. It was found that DMNS surfactant possessed great capability and efficiency of lowering the solution surface tension and the critical micelle concentration (cmc) is 0.002 mass% and the surface tension at this concentration is 29.39 mN.m^?1. It was also found that the DMNS surfactant is also greatly effective in reducing the interfacial tensions and can lower the tension of crude oil-water interface to ultra-low at very low surfactant concentration and an optimum range of sodium chloride. The lower alkali concentration is favorable for lowering DIT. The higher alkali concentration needs a higher surfactant concentration for oil flooding systems lowering DIT. Moreover, the results indicate that there obviously exists both synergism and antagonism among the surfactant, alkali and inorganic salt. The added surfactant play an important role in reducing DIT, and the prepared DMNS surfactant possesses great capability and efficiency in lowering the interfacial tension between oil and water. The salt-modified surfactant flooding systems without alkali, decreasing the cost of oil recovery and avoiding the stratum being destroyed would have a great prospect for enhanced oil recovery.     

Research Interfacial Properties of the Novel Lignosulfonates

Abstract

The interfacial tensions between the crude oil and the novel modified lignosulfonate solutions were measured by a spinning drop interfacial tension apparatus. Some effects that influence on IFT were discussed. With the increase of alkyl chain length or the number of lipophilic groups introduced, the interfacial activity of the modified lignosulfonate increases, and the optimum surfactant concentration required to reach ultra-low IFT decreases. Excellent activity at the interface of crude oil and the solutions was observed. The interfacial tensions of the modified lignosulfonates could be ultra-low over a wide range of surfactant concentration and alkali concentration without the addition of other surfactants. They are capable of being the principal surfactant in enhanced oil recovery (EOR).     

The effect of ethoxylated nonyl phenols on the interfacial tension between crude oil and water

In this study, the effect of ethoxylated nonyl phenols with ethoxy group numbers 4 and 9 (nonyl phenol 4 and nonyl phenol 9), were investigated on the interfacial tension between crude oil and water. The interfacial tensions decreased significantly in a concentration range of 0–1.25 g.l^–1. By increasing sodium chloride concentration, the time which was required to reach equilibrium interfacial tension was reduced. Therefore, sodium chloride affected the dynamic interfacial tension. However, ethoxylated nonyl phenols resisted against change of salinity. The effect of mixed surfactants on the decreasing of the interfacial tension was more than an individual surfactant, because of the synergism. The most effective mixture of a two surfactants system was observed when mass ratio of nonyl phenol 9 and nonyl phenol 4 was 0.5.     

The effect of ethoxylated nonyl phenols on viscosity of crude oil

In this study, viscosities of different crude oils was determined in the temperature range of (298–373 K) in presence of ethoxylated nonyl phenols as nonionic surfactant with ethoxy group numbers 4 and 9 (nonyl phenol 4 and nonyl phenol 9). Viscosity was measured using Viscolab PVT viscometer. Viscosity of crude oil decreased with the increase of concentration in the range of 0–1.4 g l^?1). The most radical change was observed in the presence of nonyl phenol 9. For both surfactants, the viscosities of crude oil decreased with the increase of temperature, but the effect of temperature on the viscosity of crude oil decreased when surfactant concentration increased. Because of the formation of mixed micellar aggregates, the effect of mixed surfactants on the reduction of viscosity was more obvious than individual surfactant, but mixed surfactants had very little sensitivity to the temperature than individual surfactant. The best mixture of two surfactants system was observed in the mass ratio of 3 for nonyl phenol 9 and nonyl phenol 4.     

The influence of additive molecular weight and ionic nature on the pool boiling performance of aqueous surfactant solutions

Saturated nucleate pool boiling on a horizontal cylindrical heater in aqueous solutions of surfactants, which have different molecular weights and ionic character, has been experimentally investigated. Two anionic surfactants, sodium dodecyl sulphate (SDS) and sodium lauryl ether sulfate (SLES), and two nonionic surfactants, Triton X-100 and Triton X-305, were used; their molecular weights are 288.3, 422, 624 and 1526, respectively. The boiling performance, characterized by an early onset of nucleate boiling, is significantly enhanced, and the maximum enhancement increases with decreasing surfactant molecular weight. Also, the heat transfer coefficient, normalized by dynamic σ (at 50 ms, 80°C), scales as h∝Mⁿ with n=−0.5 and 0 for anionics and nonionics, respectively. This scaling follows from the postulation that the solution's dynamic surface tension is determined by the surfactant concentration and its interfacial activity in the sublayer around the growing bubble. Correspondingly, boiling of these solutions is directly influenced by the ionic character and molecular makeup of this sublayer.     

Synthesis and Properties of a Novel Fluorescent Surfactant

Abstract

A novel kind of fluorescent surfactant by having a hydroxyl coumarin group and a sulfonate group attached to the same alkyl chain has been synthesized. The determined critical micelle concentration (CMC) values and surface tensions (γ_cmc) at CMC for the fluorescent surfactant are in good agreement with the conventional surfactants. Ultraviolet absorption and fluorescence parameters of the product against the variation of the pH values are studied. The results indicate that the absorption and fluorescence intensity attribute to the interaction between the product and OH^?. These properties make them very promising for applications of determining the interface properties.     

Investigation the impact of additives on the displacement of the onset point of asphaltene precipitation using interfacial tension measurement

The purpose of this study is to explore the impact of additives on the displacement of the onset point of asphaltene precipitation in crude oil using the interfacial tension measurement method, based on the examined oil has been taken from Iran reservoirs. The experimental results suggest that the addition of surfactants of dodecyl benzene sulfonic acid (DBSA) and coconut diethanolamide (CDEA) to the oil has triggered the onset of asphaltene precipitation. These findings imply that CDEA has a more effective role in preventing asphaltene precipitation. Also, it was observed that increasing the concentration of the surfactants has led to obtaining greater results. Finally, critical micelle concentration was calculated to be 5000 and 4700 ppm in the cases of CDEA and DBSA, respectively.     

适合大庆油田的无碱表面活性剂性能评价研究

随着油田不断开发,大庆油田开发对象正逐渐从一类油层向渗透率低、黏土矿物含量较高的二、三类油层转变,但逐步进入工业化推广阶段的三元复合驱中碱的存在会加剧对二、三类油层的伤害,因此弱碱化、无碱化成为了复合驱技术的发展方向.针对大庆油田二类油层油水条件,采用AFS-A和AFS-B无碱表面活性剂复合体系开展了二元复合驱室内研究.实验结果表明:这两种无碱表面活性剂复合体系均可在活性剂浓度为0.05％～0.3％(质量分数)范围内与大庆原油形成10-3,N/m数量级界面张力,但AFS-B复合体系亲水性较强,AFS-A复合体系亲油性较强,AFS-B复合体系抗吸附性能要好于AFS-A复合体系;驱油效率方面,在水驱基础上,AFS-A复合体系化学驱平均采收率为17.28％,AFS-B复合体系化学驱平均采收率为19.81％.     

Synthesis and Surface Activity of Novel Anionic Arylalkyl Surfactants: Sodium N-aryloleyl p-methoxyanilinesulfonics

Abstract

Anionic arylalkyl surfactants: sodium N-aryloleyl p-methoxyanilinesulfonics (SAM) were synthesized. One of them was characterized by IR and ¹HNMR. The values of critical micelle concentration (CMC) and the surface tension (γ_cmc) at the CMC were determined.     

Study on the interfacial evaporation of aqueous solution of SDS surfactant self-assembly monolayer

Researches in chemical, biological and medical engineering consider that the self-assembly monolayer formed by SDS surfactants being to retard interfacial evaporation of aqueous solution. In heat transfer, the application of SDS surfactant in water is considered to enhance the boiling heat transfer. However, to our knowledge, the mechanism of interfacial evaporation in boiling heat transfer with the application of SDS surfactants has still not been clarified. The authors tried to give a new insight into this mechanism of the interfacial evaporation through the self-assembly monolayer of SDS surfactants by developing a model, which indicates that the accessible area and the hydrophobic interaction retard interfacial evaporation, while the decrease in the incipient temperature of phase change by SDS surfactants promotes interfacial evaporation. Thus, the effect of SDS surfactants in aqueous solution on interfacial evaporation is dual: as the concentration of SDS surfactant additives is lower than an optimal value and the interfacial superheat is not extremely high, the application of SDS surfactant promotes the interfacial evaporation; otherwise, retards the interfacial evaporation.     

Boiling phenomena with surfactants and polymeric additives: A state-of-the-art review

This paper presents a state-of-the-art review with respect to studies of boiling phenomena of aqueous surfactant and polymeric additive solutions in the literature. Both nucleate pool boiling and flow boiling are concerned. First, the effect of surfactants and polymeric additives on the physical properties of aqueous surfactant and polymeric additive solutions is discussed. The measurement results of surface tensions and viscosities of aqueous surfactant and polymeric additive solutions by the authors and other researchers are presented to show the variation of the physical properties and interfacial phenomena affected by the concentrations and/or temperatures of surfactant and polymeric additive solutions. Then, a comprehensive review of boiling phenomena including both nucleate pool boiling and flow boiling with surfactants and polymeric additives is presented. It covers both experimental studies on boiling characteristics of various aqueous surfactant and polymeric additive solutions and theoretical studies on the boiling mechanisms such as the effect of surfactants and polymeric additives on nucleation process, bubble dynamics and interfacial phenomena by the methods of visualization and modeling. In addition, as one of the related interesting topics, the study of drag reduction by the addition of surfactants and polymeric additives in fluid flow is also mentioned. According to this review, several research directions related to boiling phenomena with surfactants and polymeric additives have been identified. Especially, a cross-research area on boiling phenomena with surfactants and polymeric additives in confined spaces and microchannels (micro-scale boiling heat transfer) has been emphasized because the study on this topic is very scarce but very important. To identify the main research needs on this cross-research topic, a brief review of boiling phenomena in confined spaces is also presented. Incorporated with the characteristics of boiling phenomena with surfactants and polymeric additives in large spaces, some scientific hypotheses of boiling phenomena of aqueous surfactant and polymeric additive solutions in confined spaces have been proposed based on an analysis of boiling patterns (bubble behavior). It is suggested that experimental work be done to explore this research area and to verify these hypotheses as well in the future.     

Enhancing the photocatalytic hydrogen evolution of copper doped zinc sulfide nanoballs through surfactants modification

In this study, copper-doped zinc sulfide nanoballs were successfully synthesized in DI water and ethanol solvent by a sonochemical approach using surfactants in aqueous medium, such as citric acid (CIT), sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB), cetylpyridinium bromide (CPBr), polyethylene glycol (PEG), polyvinyl pyrrolidone (PVP), and polyvinyl butyral (PVB). Since surfactants are usually organic compounds that are amphiphilic molecules and surface-active agents with unique properties stemming from their exclusive structure with a hydrophobic tail and hydrophilic head, they can self-organize to form colloidal aggregates of different morphologies. TEM images show that copper doped ZnS crystallites without surfactant have a hollow-sphere-like self-assembled nanostructure. When 2.0Cu/ZnS was prepared with CTAB surfactant, it had a flower-like microspheres. The other surfactants would make copper-doped zinc sulfide exhibit the nanospheric structure. The surfactant plays an important role on the transfer of photogenerated electrons and holes and prevents non-radiative recombination of electrons and holes at surface sites. Therefore, surfactants could significantly improve the photocatalytic activity. Hydrogen evolution from an aqueous solution containing 0.1 M Na₂S at pH 3 and 0.15 g L⁻¹ of 2.0Cu/ZnS photocatalyst with PVB surfactant had the maximum of 1137.5 μmol h⁻¹ g⁻¹.     

表面活性剂复配在三次采油中的应用

表面活性剂是制约三次采油技术发展的关键因素。将油水界面张力降低到10-3mN/m数量级、在岩石上吸附量小、与电解质和聚合物配伍性好、热稳定性和水溶液的化学稳定性好、成本低,是高效驱油用表面活性剂的发展方向。不同表面活性剂复配可产生协同增效作用,可提高表面活性剂体系的性能和对不同油水条件的适应性,降低表面活性剂用量和成本,提高复合驱的经济性。表面活性剂复配时应注意:①阳离子表面活性剂易与带负电的油层和聚丙烯酰胺等聚合物发生电中和作用,而造成吸附损失和沉淀损失,因此阳离子表面活性剂的选择和使用应慎重;②避免复配体系中各表面活性剂在应用中出现色谱分离;③同类表面活性剂复配协同效应小,但可弥补单一表面活性剂性能的不足。适合弱碱和无碱的表面活性剂复配体系以及生物表面活性剂是未来表面活性剂复配技术的研发方向。     

Use of surfactants to mitigate precipitation of nonstable asphaltensdes

In this work, we examine the effectiveness inhibition of three different surfactants (cationic, anionic, and non-ionic) with respect to aggregation of the most unstable fraction, asphaltenes, obtained from Algerian crude oil that flocculates and precipitates during oil transport and storage. Their efficacy is compared with native resins that are extracted from the same oil. We reveal from the results that the cationic surfactant didodecyl dimethyl ammonium bromide (DDAB) displayed the highest capacity to inhibit asphaltenes aggregation. This surfactant can shift considerably the aggregation onset of asphaltenes with respect to the non-ionic octylphenopoly(ethyleneglycolether)_X (TX-100) and anionic dodecyl benzene sulfonic acid (DBSA) surfactants. This finding is explained by the presence of both double alkyl chain and basic head polar (positive charge) in surfactant structure on one hand and the structural properties of studied asphaltenes (rich oxygenated negative charge sites and low aromaticity) on the other hand. Finally, the comparison between the effectiveness of native resin and the studied surfactants indicate the following order: DDAB > resin> TX-100> DBSA.     

A neural network (CSA-LSSVM) model for the estimation of surface tension of branched alkanes

The current study highlights the application of a model based on least square support vector machine (LSSVM) for prediction of surface tension of branched alkanes. An optimization algorithm, namely, coupled simulated annealing (CSA) was applied to the model. Surface tensions of alkanes show a specific interaction between adjacent molecules of the branched alkanes which affects the anisotropic dispersion force component of the surface energy. In this paper, surface tension of branched alkanes was studied in temperature range of 283.15 and 448.15 K. To evaluate the performance and accuracy of this model, statistical and graphical error analyses have been used simultaneously. By applying CSA-LSSVM on 600 data points and finding optimum parameters, the estimated values of surface tension of branched alkanes were compared with experimental data which showed a reasonable agreement with the experimental results. Results demonstrate that the model is precise and viable for prediction of solubility data. The model shows an overall R² and AARD% estimations of 0.9921 and 0.89%, respectively.     

Dynamic surface effect on boiling of aqueous surfactant solutions

Boiling of aqueous surfactant solutions is known to be drastically different from that of pure water. The experimental results showed that a small amount of surfactant additive makes the nucleate boiling heat transfer coefficient, h_b, considerably higher, and that there is an optimum additive concentration for higher heat fluxes. Beyond this optimum point, further increase in additive concentration makes h_b lower. In this work, the effect of surfactant additive on boiling is attributed to the departure from equilibrium surface tension which is produced by extension of the vapor-liquid interface during growth and coalescence of vapor bubbles in the vicinity of boiling surface. The surface tension of a surfactant solution is higher than the static value because the surfactant component cannot diffuse to the adsorbed layer promptly. This dynamic surface effect can be expressed by the Y (≡c(dσ/dc)²) value which is shown to be a representation of the elasticity of an adsorbed film as well. The similarity between the increment of h_b due to the addition of surfactant and the Y curves indicates that the dynamic surface effect may play an important role in the boiling process of aqueous surfactant solutions.     

二元体系中化学剂浓度对驱油效果的影响

表面活性剂/聚合物二元体系可以最大限度地发挥聚合物的黏弹性并具有较低的界面张力。在成本相同的情况下,二元复合物驱可达到与三元复合驱相同的驱油效果,同时减少了乳化液的负面影响,避免了由于碱的存在引起的地层及井的结垢现象。通过室内物理模拟实验,研究了非均质岩心条件下表面活性剂浓度、聚合物浓度对二元体系驱油效果的影响。实验结果表明:二元复合驱采收率可比水驱提高20%左右;随着聚合物浓度的增加,二元体系驱油效率增加;在二元体系黏度较高的条件下,随着表面活性剂浓度的降低,二元体系的驱油效率不会出现显著下降;对于非均质岩心,在较高聚合物用量条件下,可以弥补由于表面活性剂浓度的降低使二元体系油水界面张力上升而导致的体系驱油效率的下降,并在一定程度上可以降低表面活性剂的用量。     

Effects of poly(vinyl alcohol) and poly(acrylic acid) on interfacial properties and stability of compound droplets

Polymer shells, as the container of deuterium and tritium fuels, are indispensable parts for preparing the target in the inertial fusion experiments and the future inertial fusion energy plants. It is important to ensure the stability of the corresponding compound droplets, the precursor of these polymer shells. The selection of surfactants is crucial in the preparation of the compound droplets due to their important role on the stability of the compound droplets. In this paper, the effects of the concentrations of the poly (vinyl alcohol) (PVA) and the poly (acrylic acid) (PAA), and their molecular weights on the bulk and interfacial properties, as well as the relationship between the properties and the stability of the compound droplets were investigated. Moreover, the mechanisms of the PVA and the PAA preventing the coalescence and the rupture of the compound droplets were also discussed. Lower interfacial tension and higher bulk viscosity benefited reducing the risk of the rupture and the coalescence. The interfacial dilational viscoelasticity (elastic modulus, viscous modulus and phase angle) also showed an important influence on the rupture and the coalescence. This work provides a more comprehensive understanding of the coalescence and the rupture, and gives some practical advices on selecting optimal concentration of the surfactant and its molecular weight, benefiting the preparation of stable compound droplets.     

Experimental analysis of saturated pool boiling of acetone and isopropanol with added surfactant sodium lauryl sulfate over aluminum surface

The present article reports a detailed experimental study to know the effect of adding surfactants to different base fluids. For this purpose, an aqueous solution of different concentrations of surfactant with base fluids was formed and then heated at varying heat flux in a pool boiling apparatus. Acetone and isopropanol have been used as base/boiling fluids with anionic surfactant sodium lauryl sulfate (SLS) of 200, 400, 600, 800, and 1000 PPM concentration. The data obtained by heating surfactant-based fluids has been compared to the data of heating pure base fluids to establish the role of surfactants and the importance of surfactant concentration, that is, critical micelle concentration (CMC) in pool boiling augmentation. CMC value was found in the case of pool boiling of acetone with an SLS concentration of 400 PPM. However, the CMC value is found to be a lower value of SLS concentration of 200 PPM in the pool boiling process of isopropanol. Therefore, it is interesting to investigate the possible causes of such heat transfer phenomena with different values of surfactant concentration. Variations in heat flux change the degree of superheat of the aluminum heater substrate. The heat transfer performance is studied, and finally, a semi-empirical correlation is proposed to know the heat transfer coefficient and its dependency over the concentration of surfactant.     

Study on thermal stratification in liquid hydrogen tank under different gravity levels

In the present study, one CFD model is selected to research the effect of gravity scale on the thermal performance in liquid hydrogen tank. Four gravity levels (1g₀, 10^?1g₀, 10^?2g₀ and 10^?3g₀) are compared to recognize the influence of the reduced gravity on fluid thermal stratification. The results show that with the increasing of the gravity level, the vapor temperature distribution becomes more uniform, and the liquid stratum layer develops faster. Compared the CFD results with the results of two stratification theoretical models, the stratum thickness calculated by CFD model is close to the values of Tellep model. While the stratum temperature of CFD model is much closer to that of Reynolds model. With vortex occurring among two slosh baffles, the streamline in the liquid stratum likes a plume. Influenced by the surface tension in reduced gravity, liquid close to the tank wall moves up with the interface becoming curved. The interface area rises with the decrease of gravity. The gravity of 10^?1g₀ still plays the dominant role with the interface area of 10^?1g₀ being almost the same as that of 1g₀. While for others, the effect of the surface tension shows up gradually.