Stable Water In Oil Emulsions Research Articles

Continuous synthesis of surfactant stabilised water in diesel emulsion by steam condensation

Water in diesel emulsions are known to have superior combustion properties. A critical factor that determines their applicability as a fuel is their stability. In this work we propose a novel method for continuous on-board generation of stable water in oil emulsions that is best suited for direct application in internal combustion engines. Here superheated steam is generated and is brought in contact with the oil phase containing surfactant in a helically coiled tube. The steam continuously condenses resulting in micron size droplets in the oil phase. Controlled experiments were done with dodecane as the organic phase containing a surfactant. The droplets size of the dispersed phase is found to be in the range of 1–12 µm. The emulsions obtained were found to be stable for at least 15 days. The mean droplet size is determined as a function of water volume percentage, surfactant concentration and emulsion flow rate. The droplet size features obtained when diesel is used as the continuous phase is found to be similar to that obtained using dodecane.

Asphaltenes at the water-oil interface using DPD/COSMO-SAC

Asphaltenes are the heaviest fraction of crude oil. Its deposition causes large problems during oil exploitation. Sometimes it is difficult to separate the asphaltenes from the oil because of the very stable water in oil emulsions that they form. The Dissipative Particle Dynamics (DPD) has been used to study the interfacial properties of asphaltene molecules at the water-oil interface. The COSMO-SAC method was used to systematically obtaining the conservative force DPD parameters. The methodology to obtain the DPD-parameters has been tested in hydrocarbon-water systems yielding good results for the interfacial tension compared to experimental data. Asphaltene-toluene mixtures were also analyzed using this methodology in terms of diffusion coefficients and structural information showing consistent results. Ultimately, the water-asphaltene-oil systems were investigated, and the critical micelle concentration is in agreement with experimental values. Density profiles and angular analysis of asphaltene molecules at the water-oil interface have also been carried out, showing that those molecules are preferentially parallel to the interface at low asphaltene concentration, whereas at higher concentrations, entropic effects become dominant, and the molecules assume a tilted configuration. The size and number of aggregates at the water-oil interface show that asphaltenes form small aggregates at low concentrations and large structures at high concentrations.

Development of technology for destroying stable water-in-oil emulsions by ultrasonic method at the mobile well production preparing unit

Treatment of production fluids to meet the requirements of the first quality group for commercial purposes is becoming more relevant every year in the Perm Region. Most operational facilities are in the final stages of development and characterized by the high water content of production fluids, which later leads to the formation of water-in-oil emulsions (WOEs) during transportation and field preparation. When treated by traditional methods, such as thermal and thermo chemical gravity sedimentation, stable WOEs are not amenable to destruction. These preparation methods are easy to use but do not always provide the expected result. In this regard, an urgent task is to develop and implement new technologies for the preparation of hydrocarbons, which can be used separately from traditional methods, or in combination with them. This method is called ultrasound impact (USI). This article describes regularities in the influence of various parameters on the efficiency of stable water-in-oil emulsion destruction during field-based treatment with the use of USI. The paper describes the experience of using USI, as well as the high destruction efficiency of stable water-in-oil emulsions in comparison with traditional methods. The authors of the article conducted pilot tests using a mobile unit for treating production fluids with stable WOEs pre-treated by ultrasound. Following test results, the technological effect has been evaluated and recommendations for the practical application of the proposed method have been made.

Efficiency of Urea Solutions in Enhanced Oil Recovery.

We examine the applicability of urea solutions as a novel cost-effective chemical for enhanced oil recovery processes. Two sandpack flooding experiments were conducted using 5 and 10 wt % urea solutions. Another flooding experiment was also carried out using the same sandpack with fresh water and used as a reference. Supporting experiments such as interfacial tension (IFT), viscosity of water in oil (W/O) emulsions, total acid number (TAN), and Fourier-transform infrared (FTIR) spectroscopy were conducted to confirm the generation of in situ surfactants by reacting urea solutions with the naphthenic acids in bitumen and evaluate their impact on the oil recovery. The analyses of FTIR, IFT, TAN, and viscosity measurements support the generation of in situ surfactants that leads to the formation of stable water in oil emulsions and hence a more stable displacement front resulting in higher oil recovery.

Water-in-oil emulsions separation using an ultrasonic standing wave coalescence chamber

The offshore extraction of crude oil produces stable water in oil emulsion. To separate this emulsion into oil and water phases, the oil/water interfacial film is commonly destroyed by the addition of chemical demulsifiers. The use of an ultrasonic standing wave force field could be an alternative to reduce the dosage of chemical demulsifiers in the coalescence process. In this work, an ultrasonic separator of water in crude oil emulsions is investigated through the use of a high frequency ultrasonic standing wave coalescence chamber. The coalescing chamber uses the acoustic radiation force to induce the coalescence of water droplets at the pressure nodes of a standing wave field. Due to temperature fluctuations, the excitation frequency is controlled to maintain the resonance in the coalescence chamber and the voltage amplitude is controlled to deliver a given acoustic power. Experimental tests using standardized emulsions of water in oil were carried out in a laboratory processing plant. The effects of ultrasound application, flow rate, initial water content, demulsifier dosage and chamber inlet temperature were analyzed. The results show that the use of the acoustic radiation force improves the emulsion separation in all the conditions analyzed, when compared with the gravitational separation technique.

Mitigation of NOx and smoke emissions in a diesel engine using novel emulsified lemon peel oil biofuel

Lemon peel oil (LPO) is considered to be a viable alternative fuel for diesel engine applications due to its wider availability, renewable nature, easy extraction process, almost equivalent calorific value as neat diesel, and low viscosity. The present work aims to investigate the effect of novel emulsified LPO in a diesel engine in order to reduce the NOx emission without compromising the engine performance. A new ionic surfactant is introduced in the present study, namely methyl-dihydroxy propyl imidazolium chloride due to its higher hydrophilic-lipophilic balance value which helps to prepare stable water in oil emulsion. Also, Span 80 has been selected as another suitable surfactant for water in oil emulsion. Four emulsified fuel samples have been prepared using LPO, water, and different concentrations of surfactants. All the fuel samples are tested for their stability through gravitational technique for 7days. Among the emulsified samples, 92% LPO + 5% water + 2% Span 80 + 1% methyl-dihydroxy propyl imidazolium chloride by volume (LPOE2) and 93.5% LPO + 5% water + 1.5% surfactant Span 80 by volume (LPOE4) have showed better stability when compared to other emulsion fuel samples. It is also revealed that the stability of LPO emulsion is improved by the addition of two emulsions. The experimental results showed that the brake thermal efficiency of LPO emulsion is reduced to 29.87 from 34.58% of pure LPO at full load condition. Oxides of nitrogen emission and smoke emission are reduced by 21-32 and 6-15% for the LPO emulsion samples compared to pure LPO. Moreover, the diesel engine operation with emulsified form of LPO increases the HC emission about 0.1g/kWh for LPOE4 and 0.15g/kWh for LPOE2 fuels from 0.053g/kW for pure LPO at maximum power output condition. The reformulation of LPO into emulsified form increases the CO emission by 25-53% compared to pure LPO. Moreover, the reformulation of LPO into emulsions has resulted in lower cylinder pressure and heat release rate compared to pure LPO and diesel fuels.

Investigation of the activity of Acinetobacter calcoaceticus biodemulsifier to break stable water in oil emulsions

Biodemulsifier production by Acinetobacter calcoaceticus and its capability to break the stable water in oil emulsions were investigated. The chemical structure of the isolated biodemulsifiers from cultivation on various nitrogen sources were preliminarily analyzed by Fourier-transform infrared spectroscopy (FT-IR). The cultivation conditions such as temperature, pH and carbon to nitrogen source concentration (C/N) ratio were optimized for maximum demulsification activity through response surface methodology. It was disclosed that the composition of the isolated biodemulsifiers was depended on the utilized nitrogen source in the medium and altered from a cyclic lipopeptide (on soybean) to a lipopolysaccharide (on ammonium salts). The obtained optimum conditions for the biodemulsifier produced on ammonium nitrate (as the nitrogen source) were 35 °C for temperature, 10 for C/N ratio and 5 for pH. Results indicated that the produced extracellular biodemulsifier can reduce the surface tension to 38.6 mN/m and break 95% of a surfactant stabilized emulsion at the optimum conditions.

Enhanced oil removal from water in oil stable emulsions using electrospun nanocomposite fiber mats.

Fibrous mats with hydrophobic and oleophilic properties have been fabricated and used as absorbents of oil from stable water in oil emulsions. The mats were prepared by initially mixing two polymers, poly(methyl methacrylate) (PMMA) and polycaprolactone (PCL), in a common solvent. The subsequent electrospinning of the prepared solutions resulted in the production of mechanically stable fiber mats, with enhanced oil absorption capacity and oil absorption selectivity from the emulsions, compared to the pure PMMA or PCL mats. Furthermore, the formed fibrous substrates have been successful in the absorption of oil from different emulsions with a wide range of oil content, from 10 to 80 v%. The performance of the fibrous mats was optimized by the incorporation of hydrophobic silica nanoparticles, reaching oil absorption capacities of 28 g g−1 and negligible water uptake, in the emulsions with 80 v% oil content.

Performance of biodegradable cellulose based agents for demulsification of crude oil: Dehydration capacity and rate

Crude oil is a mixture of hydrocarbons, dispersed water droplets, salt, and sediment in a continuous oil phase. Presence of natural surfactants, and applied drag forces on the dispersed water during the oil production, form a stable water-in oil emulsion. Although many demulsifier agents have been developed to break the crude oil emulsion, economic and environmental problems have limited their application. In this research, cellulose-based compounds are used as demulsifier due to their unique properties. They are biodegradable, non-toxic, and environmentally friendly. The efficiency of α-cellulose, microcrystalline cellulose, ethylcellulose at different viscosity grades, and the mixture of ethylcellulose and ethoxylated coco amine are investigated to break the crude oil emulsion through bottle test. According to the experimental data, although ethylcellulose is efficient to break emulsion, low dehydration rate is the main disadvantage of that agent. Moreover, to achieve the maximum dehydration capacity and rate, the optimal demulsifier formulation is obtained based on the experimental results. Finally, the effect of temperature, agent composition, and demulsifier concentration are evaluated on the dehydration capacity and rate of selected agents. The results show that the mixture containing ethylcellulose 46 mPa s and ethoxylated coco amine presents the higher dehydration rate and capacity.

Light-Triggered Release from Pickering Emulsions Stabilized by TiO2 Nanoparticles with Tailored Wettability.

In this work, a new strategy for developing light-triggered Pickering emulsions as smart soft vehicles for on-demand release is proposed. Initially, UV-induced tailored wettability allows anchoring of TiO2 nanoparticles at the interface to prepare stable water in oil emulsions. Such emulsions show the efficacy of microencapsulation and controlled release by demulsification due to the hydrophilic conversion of the TiO2 nanoparticles using a noninvasive light irradiation trigger. A molecule of interest is selected as a model cargo to quantitatively evaluate the as-prepared Pickering emulsions for their encapsulation and release behaviors. Moreover, light-responsive emulsion destabilization mechanism is studied as a function of particle concentration, light wavelength, and light intensity, respectively, determined by drop diameter evolution and droplet coalescence kinetics plots. For consideration of application in life sciences, Pickering emulsions sensitive to visible light are also established based on nitrogen doping of TiO2 nanoparticle emulsifiers.

Modulation of Antibody Responses against Gnathostoma spinigerum in Mice Immunized with Crude Antigen Formulated in CpG Oligonucleotide and Montanide ISA720

This study aimed to investigate the antibody responses in mice immunized with Gnathostoma spinigerum crude antigen (GsAg) incorporated with the combined adjuvant, a synthetic oligonucleotide containing unmethylated CpG motif (CpG ODN 1826) and a stable water in oil emulsion (Montanide ISA720). Mice immunized with GsAg and combined adjuvant produced all antibody classes and subclasses to GsAg except IgA. IgG2a/2b/3 but not IgG1 subclasses were enhanced by immunization with CpG ODN 1826 when compared with the control groups immunized with non-CpG ODN and Montanide ISA or only with Montanide ISA, suggesting a biased induction of a Th1-type response by CpG ODN. After challenge infection with live G. spinigerum larvae, the levels of IgG2a/2b/3 antibody subclasses decreased immediately and continuously, while the IgG1 subclass remained at high levels. This also corresponded to a continuous decrease of the IgG2a/IgG1 ratio after infection. Only IgM and IgG1 antibodies, but not IgG2a/2b/3, were significantly produced in adjuvant control groups after infection. These findings suggest that G. spinigerum infection potently induces a Th2-type biased response.

A Microscopic View of Oil Slick Break-up and Emulsion Formation in Breaking Waves

The maximum stable drop size for dispersions arising from oil slicks and water in oil emulsions are shown to be controlled by Raleigh–Taylor instability or the prevalent local shear stress in breaking waves, which ever is more restrictive. Data from five experimental studies, including oils and oil in water emulsions with densities less than that of water and viscosities ranging from 0.001 to 1000 Pa s were fitted quantitatively by the model. Low viscosity oils tend to break into drops with a sauter equivalent diameter less than 0.005 m, while oils with a high viscosity and a density approaching that of water remain as large slicks. Water in oil emulsions can be formed by dispersion inversion i.e., water drops can become trapped among oil drops coalescing at the water–air surface and by water drop entrainment i.e., water entrained by gas bubbles escaping from the collapsing vortices of breaking waves, can be released in the form of fine drops as the bubbles pass through large oil slicks. Both mechanisms are shown to be active over a broad range of oil physical properties. Viscous oils with a low oil–water interfacial tension yield the most stable water in oil emulsions in breaking waves.

Determination of the shape, size and porosity of fine α-Al2O3 powders prepared by emulsion evaporation

Stable water in oil emulsions were prepared from Al(NO 3 ) 3 solutions of different molarities. Dark brown precursors were obtained from these emulsions which were evaporated by adding them dropwise into hot mineral oil. The precursors containing diaspore as raw alumina were calcined at 1000 °C and fine α-Al 2 O 3 powders were obtained. The photographs of the powders were taken by the use of an electron microscope and their particle size distributions were determined. The shapes and sizes of the powders were discussed. Their mesopore size distributions were obtained from the data of the desorption of nitrogen at 77 K. The relation between the obtained results and the concentrations of the Al(NO 3 ) 3 solutions were discussed.

Factors Causing Emulsion Upsets in Surface Facilities Following Acid Stimulation

Severe emulsion upsets in surface treating facilities following acid stimulation frequently occur after production from the stimulated well is commingled with other production. Preventing such upsets requires using optimum demulsifiers at high concentrations and eliminating, or at least minimizing, the formation of precipitates. Introduction Frequently, severe emulsion upsets occur in surface treating facilities following acid stimulation. Such upsets usually occur after production from the stimulated well is commingled with other production from nonstimulated wells. These emulsions have been extremely difficult to treat and have resulted in loss of considerable oil produced as an untreatable emulsion and a reluctance, in some areas, to use acid stimulation. Results presented in this paper show that acids partially spent on formation solids contain, in solution, potentially precipitable materials. As the pH of the produced acid precipitable materials. As the pH of the produced acid increases upon commingling with other production, fine solids are precipitated; these solids are capable of stabilizing extremely tight emulsions. The stability of such emulsions is far greater than that of emulsions stabilized by fine particles loosened from the formation or by oil-wet formation particles loosened from the formation or by oil-wet formation particles. Preventing upsets in the field requires using particles. Preventing upsets in the field requires using optimum demulsifiers and eliminating, or at least minimizing, the formation of precipitates from partially spent acids. Examples are given for handling such problems in the field. A novel technique for the reproducible formation and the study of emulsions in the laboratory is presented. The use of the technique in selecting optimum demulsifiers for the field is described. Background Historically, emulsion treatment has played a significant role in petroleum production. Much of the world's oil is produced with water and, in many cases, stable water in produced with water and, in many cases, stable water in oil emulsions occurs. An entire technology has been developed for treating such emulsions. Types of treatment include thermal, electrical, and chemical treatments. Most oilfield emulsions are stabilized by small amounts of naturally occurring, surface-active materials present in either the oil or the water, and usually can be treated with nominal amounts of chemicals or by other means. Such emulsions generally are observed at the wellhead and are believed to form either in the wellbore or in the formation. Emulsions observed following acid stimulation are significantly different. First, they do not always show up at the wellhead, but generally form only after production from the acid-treated well is commingled with production from untreated wells. Second, they are extremely difficult to treat requiring either large amounts of chemical demulsifiers or unusually long separation times. Such emulsions are a particularly serious problem in offshore operations, where it is usually impractical to separate production from individual wells and where an entire production from individual wells and where an entire field's production may be commingled before treatment. Emulsion upsets under such circumstances can result in thousands of barrels of nonpipeline-quality oil. The problem has been particularly acute in Gulf Coast fields, problem has been particularly acute in Gulf Coast fields, but also has been noticed recently to a lesser degree in production from offshore California. As more production production from offshore California. As more production comes from offshore and more acid stimulation is used in such areas, occurrence of severe emulsion problems can be expected to increase. The work reported here was related to sandstone acidizing with HC1-HF acid. JPT P. 1060