Spinning Drop Interfacial Tensiometer Research Articles

Dynamic interfacial tensions of sulfobetaine and polymers solutions: Effect of structures

To facilitate the understanding of the intrinsic mechanism responsible for the IFTs of betaine solutions, partly hydrolyzed polyacrylamide (HPAM) and hydrophobically modified polyacrylamide (HMPAM) were employed to investigate their effect on IFTs of different betaine solutions against decane using a spinning drop interfacial tensiometer. Moreover, the effects of oleic acid on the IFTs of betaine-polymer systems were also studied. The results show that the water-soluble polymers (HPAM) form the mixed adsorption film with alkyl sulfobetaine (ASB) molecules and prevent the hydrophilic groups of ASB from lying flat, which produces a minimum IFT with aging time. Besides, the hydrophobic HMPAM forms mixed micelle-like interfacial associations with ASB molecules, which results in a stronger disruption tendency for the interfacial film. The branched xylyl substituted alkyl sulfobetaine (BSB) molecules will form a tight interfacial film, therefore HPAM can’t insert into the interfacial film easily. Meanwhile, steric hindrance makes it difficult to form interfacial aggregates with HMPAM. Thus, the addition of HPAM and HMPAM polymers has little influence on the IFTs in the BSB system. The mixed adsorption of oleic acid and betaine molecules results in a significant decrease in IFTs, especially for BSB. However, in the ASB-polymer system, HPAM forms mixed adsorption film with ASB molecules and hinders the adsorption of oleic acid, accordingly IFTs change little. In contrast, the hydrophobic interaction of HMPAM promotes the adsorption of oleic acid, so the synergistic effect reduces IFTs to some extent. In the BSB-polymer system, the strong synergistic effect between oleic acid and BSB molecules is disrupted by polymers, which results in a significant increase in IFTs. The relevant results are helpful for the design of novel and efficient chemical flooding systems.

The mechanism responsible for lowering interfacial tension between heavy crude oil and betaine solutions

To clarify the mechanism responsible for the reduction of interfacial tension (IFT), the dynamic and equilibrium IFTs of different betaine solutions against n-alkanes, kerosene, heavy oil fractions model oil and crude oil have been investigated by spinning-drop interfacial tensiometer. The experimental results show that the synergism for lowering IFT between heavy crude oil and betaine solutions are controlled by two main factors. One is “size compatibility” between surfactant molecules and surface-active substances in crude oil. The other is the optimized ratio of crude oil fraction to betaine. The betaine molecules with large size of hydrophilic group can form compact interfacial film with surface-active fractions in heavy crude oil by mixed adsorption. Therefore, betaines with large hydrophilic groups show an apparent synergism with heavy crude oil in lowering IFT and can produce ultralow IFT value at optimized concentration.

Synergistic effects of nanoparticles and surfactants on n-decane-water interfacial tension and bulk foam stability at high temperature

The synergistic effects of nanoparticles and surfactants on decane-water interfacial tension, and bulk foam stability at high temperature was investigated in this study. The interfacial properties were determined using a spinning drop interfacial tensiometer while the foam stability was evaluated from the normalized foam height. The extent of interaction between nanoparticles and surfactants was estimated from the hydrodynamic nano-aggregate sizes and zeta potential values. The foam microscopic images and the bubble morphology were examined to elucidate the mechanisms of foam stabilization by nanoparticles. Results clearly showed that nanoparticles-Triton X-100 mixed system demonstrated the smallest aggregate sizes in bulk solution and considerable reduction in water/n-decane interfacial tension. Significant reduction in interfacial tension and increased foam stability occurred due to electrostatic interaction between the charged surfaces of the nanoparticles and surfactant head-groups. However, influence of electrostatic attraction was found to be dominant over the influence of electrostatic repulsion in promoting foam stability and reducing interfacial tension. The most stable foam was generated by titanium dioxide (TiO2) nanoparticles and cetyltrimethylammonium, bromide (CTAB), while the least stable foam was generated in presence of multi-walled carbon nanotubes and triton X-100. Possible reasons and mechanisms for these observations were suggested. The destabilizing influence of high temperature on foam stability was significant, however, CTAB-foam stability increased by 160% and 440% in presence of silicon dioxide (SiO2) and TiO2 nanoparticles at 80 °C. This phenomenon can be attributed to the moderate adsorption and aggregation of surface-active complex at the gas-liquid interface of the foam and Plateau borders.

Effect of Oleic Acid on the Dynamic Interfacial Tensions of Surfactant Solutions

The dynamic interfacial tensions (IFTs) of three different types of surfactant solutions, cationic surfactant hexadecyl trimethylammonium (CTAB), anionic surfactant sodium dodecyl benzenesulfonate (SDBS), and non-ionic surfactant Triton X-100 (TX-100), against model oil containing oleic acid (OA) have been investigated by a spinning drop interfacial tensiometer. The influences of the OA concentration and addition of alkali have been studied. The experimental results show that OA added to the oil phase has a significant effect on interfacial behaviors of surfactant solutions. An obvious synergistic effect on reducing IFT can be observed for low-concentration cationic surfactant CTAB solution because the tight mixed adsorption films will be formed through electrostatic attraction between CTAB and OA molecules. However, the synergistic effect will disappear at a high surfactant concentration by the formation of mixed micelles. For the anionic surfactant SDBS system, the mixed adsorption of SDBS and OA molecu...

Effect of polymer on dynamic interfacial tensions of sulfobetaine solutions

The effect of different types of polymers, partly hydrolyzed polyacrylamide (HPAM), hydrophobically modified polyacrylamide (HMPAM) and co-polymer, on the dynamic interfacial tensions (IFTs) of benzyl substituted alkyl sulfobetaine (BSB) against n-alkanes, kerosene and crude oil have been investigated by a spinning drop interfacial tensiometer. The influence of polymer concentration on IFTs was expounded. The experimental results show that betaine has high interfacial activity and the addition of polymer has great influence on both dynamic IFT behaviors and equilibrium values between surfactant solution and n-alkanes mainly by modifying the interfacial molecular arrangement on the interface. However, the addition of polymer affects the dynamic IFTs of surfactant solution against kerosene and crude oil, but has little effect on the equilibrium IFT values. Active substances existing in kerosene and the in situ produced petroleum acidic soaps play a synergistic effect with betaine to reduce the IFTs. The increase of viscosity of aqueous phase caused by polymer influence the adsorption of the surfactant at the interface, slowing down the decrease of IFTs and changing the minimum transient IFT values.

Demulsifier performance at low temperature in a low permeability reservoir

ABSTRACTThe crude oil in Longdong area is produced in the form of emulsion containing associated oil and water, which needs to be separated before dispatch to end user. Chemical demulsification under high temperature is the most widely used technology to break the emulsions. In this study a rheological method was used to determine the curve of viscosity-temperature and lower limit of temperature was determined. A series of experiments on low-temperature commercial demulsifies were implemented for studying demulsification performance by bottle test method. Mechanism of low-temperature demulsifier was studied by using spinning drop interfacial tensiometer to determine interfacial tension between the crude oil and demulsifier solution by considering the concentration. Turbiscan stability analyzer was used to study the effect of water content, temperature, and demulsifier concentration on emulsion stability. The corresponding relationship between interfacial tension and demulsification was verified through the study of low-temperature demulsifier effect on interfacial tension. Efficient low-temperature demulsifiers AR102, AR901, PR929, and PRC06 were selected. PRC06 was chosen to be the best at 40°C, and when the optimal concentration was 200 mg/L, dehydration rate was 99.51%.

Dynamic interfacial tensions of alkyl alcohol polyoxypropylene–oxyehtylene ether sulfonate solutions

Abstract The dynamic interfacial tensions (IFTs) of a series of branched alkyl ether sulfonates with different number of ethylene oxide (EO) groups and propylene oxide (PO) groups, C 8 PO 3 EO 3 S, C 8 PO 3 EO 6 S, C 8 PO 6 EO 3 S and C 8 PO 6 EO 6 S, against n-alkane have been investigated by spinning drop interfacial tensiometer. The influences of surfactant concentration and salinity on IFT were expounded. The effect of alkyl chain carbon number (ACN) of the oil phase on the IFT has also been investigated. The experimental results show that the dynamic IFTs of C 8 PO 3 EO 6 S and C 8 PO 6 EO 3 S decrease and then reach a plateau with time, shown as an L-shaped; on the other hand, the dynamic IFTs go through minima and show V-shaped for C 8 PO 3 EO 3 S and C 8 PO 6 EO 6 S solutions at high bulk concentration. Moreover, V-shaped curve also appears at low bulk concentration for C 8 PO 3 EO 3 S and C 8 PO 6 EO 6 S with addition of NaCl. An increase in the length of alky chain of the oil molecules will enhance V-shaped phenomenon as well. This research suggests that the ratio of PO groups to EO groups is a key factor for controlling interfacial properties. Under optimal conditions, the transient and equilibrium ultralow IFTs can be obtained by C 8 PO 6 EO 6 S and C 8 PO 6 EO 3 S solutions respectively. Previous studies have shown that the interfacial concentration of surfactant monomers and the cross-sectional area of surfactant molecule at the interface are the two most important factors in dominating ultralow IFT. A mechanism base on the variation of cross-sectional area of surfactant molecule due to the PO groups looping away from the aqueous phase into the oil phase has been provided for understanding the ultralow IFT property for anionic–nonionic surfactants.

Effect of Crude Oil Fractions on Interfacial Tensions of Novel Sulfobetaine Solutions

The dynamic interfacial tensions (IFTs) of two novel zwitterionic surfactants with different hydrophobic groups, alkyl sulfobetaine (ASB), and xylyl substituted alkyl sulfobetaine (XSB), against kerosene, crude oil, and model oils containing crude oil fractions, such as resins, asphaltenes, saturates, aromatics, and acidic fractions, have been investigated by a spinning drop interfacial tensiometer. The experimental results show that XSB solutions show higher interfacial activity than ASB against kerosene because of the larger size of the hydrophobic part of the XSB molecule. The petroleum acids have high interfacial activity and can adsorb onto the interface. For ASB solutions, the synergism mixed adsorption of betaine and acid molecules lowers IFT values. On the one hand, the partly displacement of XSB molecules by petroleum acid at the interface results in the increase of IFTs. Therefore, resins, aromatics, and acidic fractions show strong effects on IFTs of betaine solutions. On the other hand, asphaltenes and saturates have little effect on interfacial properties. Moreover, the hydrophilic part of the betaine molecule at the interface may vary its orientation from vertical to flat with aging time. Therefore, the dynamic IFT curves of ASB solutions against model oils show “V” shape for resins, aromatics, and acidic fractions.

Effect of Polymer on Dynamic Interfacial Tensions of Anionic–nonionic Surfactant Solutions

The dynamic interfacial tensions (IFTs) of enhanced oil recovery (EOR) surfactant/polymer systems against n-decane have been investigated using a spinning drop interfacial tensiometer in this paper. Two anionic–nonionic surfactants with different hydrophilic groups, C8PO6EO3S (6-3) and C8PO6EO6S (6-6), were selected as model surfactants. Partially hydrolyzed polyacrylamide (HPAM) and hydrophobically modified polyacrylamide (HMPAM) were employed. The influences of surfactant concentration, temperature, polymer concentration, and oleic acid in the oil on IFTs have been studied. The experimental results show that anionic–nonionic surfactants can form compact adsorption films and reach ultralow IFT (10−3 mN/m) under optimum conditions. The addition of polymer has great influence on dynamic IFTs between surfactant solutions and n-decane mainly by the formation of looser mixed films resulting from the penetration of polymer chains into the interface. The compact surfactant film will also be weakened by the competitive adsorption of oleic acid, which results in the increase of IFT. Moreover, the penetration of polymer chains will be further destroyed surfactant/polymer mixed layer and lead to the obvious increase of IFT. On the other hand, polymers show little effect on the IFTs of 6-6 systems than those of 6-3 because of the hindrance of longer EO chain of 6-6 at the interface.

Effect of organic alkali on interfacial tensions of surfactant solutions against crude oils

Abstract The dynamic interfacial tensions (IFTs) of petroleum sulfonate and organic alkali combined solutions against crude oils with different acid numbers have been investigated by a spinning-drop interfacial tensiometer. The influences of surfactant concentration, organic structure and concentration on the IFTs were expounded. The experimental results show that the petroleum acids can react with the organic alkalis and produce the surface-active soaps at the interface in situ. Both the ultralow transient and equilibrium IFTs can be reached at optimum conditions. The structures and contents of petroleum acids play important roles in controlling IFTs between the crude oils and the organic alkaline solutions. It is believable that fatty acids contribute to the lower transient IFT in short time and aromatic acids with condensed ring determine the equilibrium IFTs. The crude oil with higher acid number usually shows lower IFT values, however the structures of petroleum acids are more crucial factors and the crude oils with similar acid numbers may behave quite different dynamic IFT behaviors. The concentrations and structures of organic alkalis also strongly affect the IFTs of crude oil–alkaline solution systems. An obvious IFT minimum appears as a function of organic alkali concentration and the increase of molecular size of the organic counterion results in a loosely packed film and an increment of IFT. By adding petroleum sulfonate to organic alkaline solutions, the IFTs may be easily reduced to an ultralow value through the formation of close-packed mixed adsorption film containing surfactant, petroleum acid and soap molecules. For organic alkalis with larger molecular size, the loose mixed adsorption film is beneficial for the synergistic effect among petroleum acids, soaps and surfactant molecules, which can enlarge the applying reservoirs of organic alkali.

Effect of Organic Alkalis on Interfacial Tensions of Surfactant/Polymer Solutions against Hydrocarbons

The dynamic interfacial tensions (IFTs) of enhanced oil recovery (EOR) surfactant/polymer/organic alkali systems against a homologous series of alkanes have been investigated by a spinning drop interfacial tensiometer. Two organic alkalis with different molecular sizes, ethanolamine (EA) and diethanolamine (DEA), two surfactants with high interfacial activity, heavy alkyl benzenesulfonate (HABS) and petroleum sulfonate (SLPS), and two kinds of polymers, partly hydrolyzed polyacrylamide (HPAM) and hydrophobically modified polyacrylamide (HMPAM), were employed to study the real mechanisms controlling the IFT behavior. The experimental results show that the addition of organic alkali may affect the dynamic IFTs of surfactant solutions through different mechanisms. First, the possible reaction of organic alkali with the oil-soluble components in industrial surfactants will influence the surface active spices at the interface and enhance the dynamic behavior. Second, the hydrophilic–lipophilic balance (HLB) of the surfactant may vary, and the surfactant may become more water-soluble because of the ionization of oil-soluble components, especially for HABS. Finally, the organic counterion with larger molecular sizes may affect the arrangement of interfacial surfactant molecules. For both HABS and SLPS surfactants, interfacial interactions between the hydrophobic part of surfactants and the hydrophobic blocks of HMPAM will reduce the interfacial concentration of surfactant monomers by forming aggregates and result in an obvious increment of the IFT value. On the other hand, HPAM will obviously enhance the water solubility of the surfactant/organic alkali solutions and reduce the IFT values for the hydrocarbons with lower alkyl carbon number (ACN).

Research of Gray Relation Entropy of Oil–Water Interfacial Property to Chemical Components of Bitumen

The basic properties, composition, and structure of four base bitumens: Karamay, CNOOC, SK, and Kunlun were analyzed. The interfacial tension between soap solution-stimulant oil and asphalt was investigated using a spinning drop interfacial tensiometer. The relationships between the oil–water interfacial properties and the chemical compositions of the chosen bitumen blends were studied by means of gray correlation entropy method using the MATLAB platform. Furthermore, the relationship between the oil–water interfacial properties and the chemical composition of the bitumen were also discussed. It was shown that in the four fractions of bitumen, the aromatic compound content played a decisive role influencing the oil–water interface's properties. With regard to the elemental composition, the content of heteroatoms and sulfur played a decisive role in the oil–water interfacial properties. For the structure parameter, more aromatic carbon and cycloalkane-derived carbon, a stronger condensation index of those aromatic rings, and a low alkyl carbon content helped to enhance the interfacial activity of the bitumen. The basic properties of asphalt affected its macro-performance, but did correlate with the any measured oil–water interface properties.

Dynamic interfacial tensions of p -( n -lauryl)-benzyl polyoxyethylene ether carboxybetaine solutions

Abstract The dynamic interfacial tensions (IFT) of four p -( n -lauryl)-benzyl polyoxyethylene ether carboxybetaine C 12 BE x CB ( x =0, 1, 2, 3) have been investigated by a spinning drop interfacial tensiometer. The influence factors such as ethylene oxide group, surfactant concentration, organic base, electrolyte concentration and type are explored between C 12 BE x CB solutions and two oils including n -alkane model oil and Shengli crude oil. It is found that the n min (the minimum alkane carbon number) and IFT min increase with increase in the ethylene oxide group for n -alkane model oil systems. For Shengli crude oil, the C 12 BE x CB surfactants used alone cannot reduce the IFT to ultralow value. In order to meet the demand, the organic base, monoethanolamine (MEA), is applied together with C 12 BE x CB to form organic base/surfactant system. The results show that there exists a synergistic effect between organic alkaline MEA and C 12 BE x CB surfactant. At optimum MEA concentration (0.10 wt%) and optimum ethylene oxide group number ( x =0, 1), the IFT value becomes lower than 10 −2 mN/m. All these results show that the interfacial surfactant concentration and the surfactant molecular size are two most important factors in dominating ultralow IFT. Moreover, it is found that electrolyte concentration and type have little effects on IFT and the C 12 BE x CB surfactants exhibit good salinity resistance.

Effect of Fatty Acids on Interfacial Tensions of Novel Sulfobetaines Solutions

The dynamic interfacial tensions (IFTs) of two zwitterionic surfactants with different hydrophobic groups, alkyl sulfobetaine (ASB) and benzyl substituted alkyl sulfobetaine (BSB), against hydrocarbons, acidic model oils containing fatty acids, and three crude oils have been investigated by a spinning drop interfacial tensiometer. The influences of concentration and alkyl chain length of fatty acids on the IFTs of two betaine solutions were expounded. The effect of the alkyl chain carbon number (ACN) of the oil phase on the IFTs has also been researched. The experimental results show that the whole hydrophilic part of the betaine molecule (anionic-cationic part and the hydroxyl) is almost flat at the interface, which results in the larger occupied space of the hydrophilic part at the interface. Therefore, the branched and benzyl-substituted betaine, BSB, has a larger sized hydrophobic part and can form a more compact adsorption film than linear ASB molecules. The IFT values decrease obviously when fatty acids are added into the oil phase due to the formation of mixed adsorption films. This synergism in reducing IFT is controlled by the “chain length compatibility” and the optimum acid concentration. The ultralow IFT values can be reached when the carbon number of the alkyl chain of the fatty acid is more than 12. The IFTs of both BSB and ASB solutions against different crude oils are lower than those against pure hydrocarbons due to the formation of mixed adsorption films of betaine and petroleum acid molecules. These experimental results also confirm that the acidic model oils can represent crude oil for IFT studies to some extent.

Study on the Interfacial Tensions Between Oils and Alkylbenzene Sulfonate Gemini Surfactant Solutions

Interfacial tensions (IFT) of five alkylbenzene sulfonate Gemini surfactants Ia, Ib, Ic, Id, and Ie at different oils/water systems were measured by a spinning drop interfacial tensiometer. And critical micelle concentration (CMC), the interfacial tension at CMC (γCMC), maximum interfacial excess concentration (Γ max) and the surface area per molecule (Amin) were calculated. The results indicated that the CMC values determined with interfacial tension method were lower than those determined with surface tension method. And γCMC for Ie is larger than that for Ia, Ib, Ic, and Id. In addition, the effects of temperature and hydrophobic chains on dynamic IFT were also studied. With the increment of temperature, dynamic IFT is easier to reach a stable value. However, with the increment of hydrophobic chains, dynamic IFT is more difficult to reach a stable value. Each Gemini surfactant produces a minimum IFT when measured against a different n-alkane.

Lower critical solution coexistence curve and physical properties (density, viscosity, surface tension, and interfacial tension) of 2,6-lutidine + water

The coexistence curve and physical property data (densities, viscosities, surface tensions, and interfacial tensions of the equilibrated coexisting phases) for 2,6-lutidine+water have been determined over the range 34-60 o C, and the density and viscosity differences calculated. The compositions were determined through the refractive index at 22 o C, densities by a commercial electronic oscillating U-tube, viscosities by a U-tube viscometer, surface tensions by a du Nouy ring method, and interfacial tensions by a spinning drop interfacial tensiometer

AN INVESTIGATION OF THE FACTORS INFLUENCING TRANS [ENT INTERFACIAL TENSION BEHAVIOR IN CRUDE OIL/ALKALINE WATER SYSTEMS

Abstract The interfacial tension (IFT) dynamics of crude oil/alkaline water systems have been examined using the spinning drop interfacial tensiometer. Both synthetic and natural crudes were employed in the study; however, it was found that synthetic crudes frequently exhibited behavior quite different from that observed with natural crudes. Two crude oils were fractionated and the interfacial tension behavior of the fractions against alkaline water was investigated. Interfacial tension reduction was related to the presence of carboxylic acid components. The stabilities of the interfacial tension minima with time were related to the water solubility of the surface active species, and the ease of formation of their surface inactive, undissociated acid salts, as well as, the temperature and oil viscosities. The use of the spinning drop interfacial tensiometer in evaluating the IFT behavior of crude oil/alkaline systems was assessed.

Structural interpretation of the interfacial properties of aqueous solutions of methylcellulose and hydroxypropyl methylcellulose

Interfacial properties of aqueous solutions of methyl and hydroxypropyl methyl ethers of cellulose are important in foam and emulsion stability, detergency and many other applications involving surface activity of these cellulose ethers. Interfacial tensions of aqueous solutions of these cellulose ethers are measured using a spinning drop interfacial tensiometer. A general correlation is found between interfacial tension and the degree of substitution of methoxyl and hydroxypropyl groups. From thermodynamic considerations it is proposed that these cellulose ethers, for a constant degree of substitution, should exhibit the lowest interfacial tension values for a polymer having the most uniform distribution of substituent groups along the backbone. Other factors which influence the interfacial tension values are surface gelation of adsorbed polymer, molecular weight, concentration of cellulose ether in water phase, ageing time, temperature, and the type of organic phase.

Spinning drop interfacial viscometer

The spinning drop interfacial tensiometer can be used to measure the two interfacial viscosities, if a small oscillation is imposed upon the angular velocity of the tube. A first-order perturbation analysis is described with numerical results for a wide variety of cases. The experiment is appropriate for measuring the surface viscosities at a liquid-gas interface in the limit of dilute solutions, but it is not recommended for liquid-liquid interfaces. It may be more easily adapted to elevated pressure measurements than any other currently available.

Multicell spinning drop interfacial tensiometer

The design and performance characteristics of a thermostated multicell spinning drop interfacial tensiometer are described. The instrument features simple and reliable commercial components, +/-1 degrees C thermostating, reduced operational vibration, cells designed to reduce problems associated with gyrostatic equilibrium, and the capability to measure interfacial tensions between six pairs of liquids simultaneously.