Showing papers on "Emulsified fuel published in 2016"

Water-in-water (W/W) emulsions

Abstract: Water-in-water (W/W) emulsions are colloidal dispersions of an aqueous solution into another aqueous phase. Such dispersions can be formed in mixtures of at least two hydrophilic macromolecules, which are thermodynamically incompatible in solution, generating two immiscible aqueous phases. W/W emulsions are much less known than conventional oil-in-water or water-in-oil emulsions, despite the fact that phase separation in aqueous mixtures is highly common. The thermodynamics and the phase behavior of segregative phase separation in mixtures of hydrophilic polymers have focused a great attention, with many excellent scientific reports in the literature. However, the kinetic stability of water-in-water emulsions is generally difficult to control, since amphiphilic molecules do not adsorb on water-water interfaces. Consequently, surfactants are not good stabilizers for W/W emulsions, and until recently, only a limited number of scientific studies have dealt with the formation and stabilization of emulsions in aqueous two-phase systems. Recent advances and successful results in the stabilization of these emulsions, by alternative mechanisms, have triggered a renewed interest. Nowadays, fast progress is being made in formation and stabilization methods, and new knowledge is rapidly acquired, opening a wide range of novel possibilities for practical applications. Interestingly, highly stable water-in-water emulsions can be formulated using fully biocompatible and edible components, and consequently, these emulsions can be used in food formulations, among many other interesting applications. This review describes the general background of research in the field, and focuses on recent scientific advances, including phase behavior, formation, stability and kinetic aspects, as well as applications such as formation of microgels, encapsulation and drug delivery.

Effect of nanofluid additives on performances and emissions of emulsified diesel and biodiesel fueled stationary CI engine: A comprehensive review

Abstract: This research paper reports the results of various researches carried out up to 2015 on the performance and emission characteristics of compression ignition (CI) engine using nano particles additives in diesel, biodiesel and water emulsified fuels. There are two methods of reducing the exhaust gas emission of the CI engine. First method is to reduce the emissions by using exhaust gas treatment devices like catalytic converter, diesel particulate filter. However, use of these devices affects the performance of CI engine. Second method to reduce emissions and improve performance of CI engine is the use of fuel additive. Main pollutants of CI engine are oxide of nitrogen (NOx) and particulate matter (PM). However, it is difficult to control NOx and PM simultaneously. Many researchers report that the best method to control the emissions and improve the performance is the use of nano particles additives and water emulsified fuels. This research paper also reports the biodiesel fuel as an alternative to diesel fuel by using various nano particle additives. Comparative studies of effects on various properties of diesel and biodiesel fuels without/with water contents and nano particles additives by previous researchers are done. Most of the researchers reported improved performance and reduction in emission characteristics with dosing of nano particles additives in diesel and biodiesel.

Dried and Redispersible Cellulose Nanocrystal Pickering Emulsions

Abstract: The effect of tannic acid (TA) and water-soluble cellulose derivatives on the properties of Pickering emulsions stabilized by cellulose nanocrystals (CNCs) was investigated. The potential to both fully dry CNC-stabilized emulsions and to redisperse the dried emulsions in water is demonstrated. When CNCs are mixed with excess adsorbing polymer, either methyl cellulose or hydroxyethyl cellulose, followed by emulsification with corn oil, oil-in-water emulsions can be transformed without oil leakage into solid dry emulsions via freeze-drying. However, these dry emulsions exhibit droplet coalescence within the solid matrix and thus cannot be redispersed. Addition of TA (after emulsification) imparts dispersibility to the dried emulsions due to complexation between the cellulose derivatives and TA which condenses the “shell” around the oil droplets. When dried emulsions with TA are placed in water, the emulsion droplets redisperse readily without the need for high energy mixing, and minimal change in emulsion d...

Oil-in-oil emulsions stabilised solely by solid particles.

Abstract: A brief review of the stabilisation of emulsions of two immiscible oils is given. We then describe the use of fumed silica particles coated with either hydrocarbon or fluorocarbon groups in acting as sole stabilisers of emulsions of various vegetable oils with linear silicone oils (PDMS) of different viscosity. Transitional phase inversion of emulsions, containing equal volumes of the two oils, from silicone-in-vegetable (S/V) to vegetable-in-silicone (V/S) occurs upon increasing the hydrophobicity of the particles. Close to inversion, emulsions are stable to coalescence and gravity-induced separation for at least one year. Increasing the viscosity of the silicone oil enables stable S/V emulsions to be prepared even with relatively hydrophilic particles. Predictions of emulsion type from calculated contact angles of a silica particle at the oil–oil interface are in agreement with experiment provided a small polar contribution to the surface energy of the oils is included. We also show that stable multiple emulsions of V/S/V can be prepared in a two-step procedure using two particle types of different hydrophobicity. At fixed particle concentration, catastrophic phase inversion of emulsions from V/S to S/V can be effected by increasing the volume fraction of vegetable oil. Finally, in the case of sunflower oil + 20 cS PDMS, the study is extended to particles other than silica which differ in chemical type, particle size and particle shape. Consistent with the above findings, we find that only sufficiently hydrophobic particles (clay, zinc oxide, silicone, calcium carbonate) can act as efficient V/S emulsion stabilisers.

Experimental investigation on the role of indigenous carbon nanotube emulsified fuel in a four-stroke diesel engine

Abstract: Effect of carbon nanotube emulsified fuel in a single-cylinder water-cooled four-stroke diesel engine was studied. CNT were produced by indigenous flame synthesis method. Water diesel emulsion was ...

Carboxymethylated lignins with low surface tension toward low viscosity and highly stable emulsions of crude bitumen and refined oils

Abstract: Kraft and organosolv lignins were subjected to carboxymethylation to produce fractions that were soluble in water, displayed a minimum surface tension as low as 34 mN/m (25 °C) and a critical aggregation concentration of ∼1.5 wt%. The carboxymethylated lignins (CML), which were characterized in terms of their degree of substitution ( 31 P NMR), elemental composition, and molecular weight (GPC), were found suitable in the formulation of emulsions with bitumens of ultra-high viscosity, such as those from the Canadian oil sands. Remarkably, the interfacial features of the CML enabled fuel emulsions that were synthesized in a very broad range of internal phase content (30–70%). Cryo-replica transmission electron microscopy, which was used here the first time to assess the morphology of the lignin-based emulsions, revealed the droplets of the emulsion stabilized with the modified lignin. The observed drop size (diameters x and CO emissions and maintained a relatively high combustion efficiency. The results highlight the possibilities in high volume application for lignin biomacromolecules.

Novel stabilisation of emulsions by soft particles: polyelectrolyte complexes

Abstract: We put forward the concept of a novel particle stabiliser of oil-water emulsions, being the polyelectrolyte complex (PEC) formed between oppositely charged water-soluble polymers in cases where either polymer alone is incapable of stabilising an emulsion. Using poly(4-styrene sulfonate) sodium salt, PSSNa and poly(diallyldimethylammonium chloride), PDADMAC, of low polydispersity and similar molecular mass, we correlate the behaviour of their mixtures in water with that of emulsions after addition of oil. In aqueous mixtures, spherical particles of diameters between 100 and 150 nm are formed through electrostatic interactions between charged polymer chains. Around equal mole fractions of the two polymers, the zeta potential of the particles reverses in sign and emulsions of oil-in-water (o/w) for a range of oils can be prepared which are the most stable to coalescence and creaming. The effects of PEC concentration and the oil : water ratio have been examined. All emulsions are o/w and stability is achieved by close-packed particle layers at drop interfaces and particle aggregation in the continuous phase. Increasing the salt concentration initially causes destabilisation of the aqueous particle dispersion due to particle aggregation followed by dissolution of particles at high concentrations; the corresponding emulsions change from being stable to completely unstable and are then re-stabilised due to adsorption of uncharged individual polymer molecules.

Rheological and stability study of water-in-crude oil emulsions

Abstract: The formation of crude oil emulsion is a prevalent oilfield problem that can cause significant flow assurance issues during oil production, treatment and transportation. When they occur, emulsion problems are very difficult to solve and can lead to numerous operational problems like; creating high pressure drops in pipes and/or flowlines, production of off-specification crude oil and tripping of separation equipment. These emulsions can be very stable as a result of the presence of polar compounds, such as asphaltenes and resins, that play the role of natural surfactants and also because of the occurrence of many types of fine solids that can form resistant films at the crude oil/water interface. Solid particles also play significant roles in stabilizing emulsions. The water produced during oil production is either produced as free water, and so it will settle out fairly quickly, or the water may be combined with oil in the form of emulsions. This is more prevalent when producing oil from mature oilfields, where water production is relatively large. Under standard oilfield conditions the most common form of emulsion is a water-in-oil emulsion; a dispersion of water droplets in oil. In this work, the authors studied the consequence of different water-cuts and the presence of an emulsifier on the stability of water-in-oil emulsions. The rheological properties of W/O emulsions with different water cuts (10-50 v/v %) at different temperatures (25°C – 60°C) were studied. Rotational rheology and stability of the emulsions were studied on emulsions aged for 30 days. Generally, the results revealed that the presence of an emulsifying agent, difference in water content, shear rate and temperature significantly affect emulsion stability and rheological properties

Performance and emission characteristics of a diesel engine fuelled with emulsified biodiesel-diesel fuel blends

Abstract: In this study, effects of emulsified fuels on the performance and emissions of a diesel engine were investigated experimentally. Effective power, specific fuel consumption and thermal efficiency as well as emissions of carbon monoxide, hydrocarbon, nitrogen oxide and carbon were considered as parameters for the investigation. Two emulsified fuels, namely B20W10 and B20W15, containing 10 and 15% water by volume, respectively, were prepared by using diesel fuel-biodiesel blend (B20). The emulsified fuels were tested in a naturally aspirated, direct injection diesel engine at partial load conditions. The test results obtained from the emulsified fuels were compared with those of neat diesel fuel and B20. It was found that the emulsified fuels yield higher specific fuel consumptions, while they cause only slight changes in thermal efficiency. The emulsified fuels are very capable of reducing NOx emission at all engine loads. On the other hand, the use of emulsified fuels brings about significant increase in CO and HC emissions at low engine loads, while they cause moderate CO and HC emissions at high engine loads.

Factors affecting emissions from diesel fuel and water-in-diesel emulsion

Abstract: The purpose of this research is to investigate the effect of addition of surfactant and water in diesel and to make an emulsified fuel considering the needs for vehicle performance and its cleanest possible operation. The total surfactant concentration in each of the diesel-water emulsion samples studied (span 20, span 80, tween 20, tween 80) is fixed at 1% w/w. The water content is variable at 5–15% w/w and the diesel content is varied from 84 to 94% w/w. Among all the tested nonionic surfactants, tween 80 is found to prominently reduce the carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NOx) emissions. Tween 20 reduced the NOx emission to a greater extent. Diesel emulsion with a fixed ratio of span 80 and tween 80 (1:1) efficiently reduced the overall emissions as compared to diesel alone. The developed diesel emulsion employed with nonionic surfactants clearly reduced the harmful engine emissions such as CO, HC, and NOx, signifying them as a future potential emulsifier in diesel fue...

Prediction of the viscosity of water-in-oil emulsions

Abstract: Water-in-oil (W/O) emulsions occur in different parts of petroleum recovery and since their properties are different from those of crude oil and water, it is essential to find information about the...

Dewatering Bitumen Emulsions Using Interfacially Active Organic Composite Absorbent Particles

Abstract: One of the major challenges in petroleum production is the formation of undesirable emulsions, which often leads to an increased cost for downstream operations. This problem is exacerbated for bitumen, which contains a greater fraction of interfacially active materials known to stabilize small emulsified water droplets that are extremely difficult to separate. To accelerate separation of emulsified water droplets from bitumen, chemical demulsifiers are extensively used to modify interfacial properties, promote droplet flocculation, and facilitate coalescence of the emulsified droplets. However, the use of chemical demulsifiers is rather system-specific as a result of the overdosing phenomenon. As an alternative to chemical demulsification, composite absorbent particles, prepared by dehydrating well-designed water-in-oil emulsion droplets, were proposed to promote dewatering of water-in-diluted bitumen emulsions. The composite particles were composed of nanosize magnetic particles dispersed in an absorbent...

Preparation and physicochemical characterization of ketoprofen-loaded emulsions

Abstract: The objective of this study was to prepare ketoprofen-loaded emulsions. The emulsions were formulated by mixing soybean oil, surfactants (a mixture of Tween 20 and Tween 80), and distilled water. To determine the most suitable composition for the emulsions, a phase diagram was drawn, representing a mixture of soybean oil, surfactants, and distilled water. From the phase diagram, one-phase formulations were selected and the particle sizes of the formulations were compared. The stability of each formulation was confirmed over 4 weeks at 4 °C, by looking for any change in particle size. The effect of dilution on the pH of emulsion formulations was recorded. A soybean oil concentration of 5 % was sufficient to obtain emulsions. The surfactants used were a mixture of Tween 20 and Tween 80 in a 1:2 ratio, to ensure high ketoprofen solubility. Three formulations, termed E1, E2, and E3, produced emulsions with relatively small particles. The ketoprofen-loaded E1 formulation resulted in the smallest particles. The three formulations were physically stable for 4 weeks with no significant change in particle size. Dilution with distilled water did not alter the pH of the three emulsion formulations, but did change the conductivity. In conclusion, ketoprofen was solubilized by the emulsion formulation, and then remained stable when maintained at 4 °C; additionally, while the pH was unaltered, the conductivity of the formulation was changed by dilution with distilled water.

An overview of experimental techniques of the investigation of water-diesel emulsion characteristics droplets micro-explosion

Abstract: Emulsified fuels considered as a promising alternative fuel that could solve and meet the increasingly stringent emission regulations for diesel engines due to their capability of reduction the harmful exhaust emission, such as carbon monoxide (CO), nitrogen oxides (NOx) and particulate matter (PM). The admission of water into the diesel fuel has significant advantages. One of these advantages is the possibility of occurrence of the so-called micro-explosion phenomena. There is a number of experimental techniques and visualization systems to investigate and analyse the uses of the water-diesel (W/D) emulsion fuel, especially regarding micro-explosion phenomena. Micro-explosion is the rapid breakup of fuel droplets and hence burst into smaller droplets which enhance fuel evaporation and hence improving the air-fuel mixing process. An investigation of micro-explosion of the smaller droplets is important. This review paper discussing the advantages of using the emulsion fuel and the different experimental techniques used to detect the micro-explosion phenomena in addition to the factors affecting the onset of micro-explosion processes and proposes potential research areas for W/D emulsion fuel studies. Most of the studies in the literature agree that W/D does result in a reduction in NOx and PM exhaust gas emissions. There is, however, some inconsistencies of the experimental techniques with respect to the heating process which affects the onset and the strength of the micro-explosion process. The factors that affect the microexplosion phenomena consist of different parameters such as the distribution of the water in the emulsion, the size of the emulsion droplet, type and percentage of the surfactant, ambient temperature and pressure. ©2006-2016 Asian Research Publishing Network (ARPN).

Effect of Dispersed Phase Viscosity on Stability of Emulsions Produced by a Rotor Stator Homogenizer

Abstract: Stability is one of the key quality parameters of emulsion systems, which goes a long way in predicting the shelf life of emulsion products. In this study, the effect of dispersed phase (oil) viscosity on emulsion stability was investigated by preparing oil-in-water emulsion samples of varying linseed and vegetable oil viscosities between 0.022 Pa.s and 4.00 Pa.s. The destabilization characteristics of emulsions prepared emulsions were followed by monitoring changes in droplet sizes and distribution as the emulsions aged. The ageing of the emulsions was accelerated by subjecting the samples to freeze-thaw tests. Polysorbate20 (Tween 20) surfactant was used as the emulsifier and a Silverson L4R mixer was used to provide homogenisation at speed of 7000 rpm. The droplet size analysis was done by laser diffraction. Results from the droplet size distribution analysis showed average droplet sizes increased as the dispersed phase viscosity of the emulsions increased.

Stability and Oil Migration of Oil-in-Water Emulsions Emulsified by Phase-Separating Biopolymer Mixtures.

Abstract: Oil-in-water (O/W) emulsions with varying concentration of oil phase, medium-chain triglyceride (MCT), were prepared using phase-separating gum arabic (GA)/sugar beet pectin (SBP) mixture as an emulsifier. Stability of the emulsions including emulsion phase separation, droplet size change, and oil migration were investigated by means of visual observation, droplet size analysis, oil partition analysis, backscattering of light, and interfacial tension measurement. It was found that in the emulsions prepared with 4.0% GA/1.0% SBP, when the concentration of MCT was greater than 2.0%, emulsion phase separation was not observed and the emulsions were stable with droplet size unchanged during storage. This result proves the emulsification ability of phase-separating biopolymer mixtures and their potential usage as emulsifiers to prepare O/W emulsion. However, when the concentration of MCT was equal or less than 2.0%, emulsion phase separation occurred after preparation resulting in an upper SBP-rich phase and a lower GA-rich phase. The droplet size increased in the upper phase whereas decreased slightly in the lower phase with time, compared to the freshly prepared emulsions. During storage, the oil droplets exhibited a complex migration process: first moving to the SBP-rich phase, then to the GA-rich phase and finally gathering at the interface between the two phases. The mechanisms of the emulsion stability and oil migration in the phase-separated emulsions were discussed.

A New System of Multiple Emulsions with Lamellar Gel Phases from Vegetable Oil

Abstract: Emulsions are excellent pharmaceutical vehicles used in both the pharmacy and cosmetic industries. Vegetable oils have several effects/benefits on skin and can be used in emulsions to release principal active components for cosmetic purposes. Herein, multiple W/O/W emulsions were formulated in a one-step emulsification method, and the resulting anisotropic structures were characterized by x-ray diffraction measurements. The multiple emulsions obtained were stable and maintained their anisotropic structures over 2 years. WAXS (wide-angle x-ray scattering) measurements of these emulsions suggested that the carbon chains of the surfactant around the globules are disposed in a gel network phase. Furthermore, SAXS (small-angle x-ray scattering) measurements indicated that the surfactant is organized in lamellar layers around the globules. Thus, for the first time, we demonstrated that stable lamellar gel phase multiple emulsions can be made from vegetable oils. In addition to having the advantage of being prep...

Rheological properties of water-in-diesel fuel emulsions

Abstract: The addition of water dispersed phase into the diesel continuous phase will lead to the formation of water-in-diesel (W/D) emulsion, which significantly reduces the pollution level of NOx and particulate matters in the diesel engines. The study of the rheological properties of stable W/D emulsions is important to understand the flow characteristics of these emulsions. Pure diesel fuel and three samples of W/D emulsions (10%, 20%, and 30% by volume water) were examined. Pure diesel fuel exhibits a Newtonian profile since its viscosity remains constant with the shear rate. All W/D emulsions display higher viscosity than diesel fuel with non-Newtonian flow behaviour of yield pseudoplastic response. The viscosity of the W/D emulsions decreases with the shear rate and water addition. The flow behaviour of pure diesel fuel can be described by the Power law model. The Casson model very sufficiently fits the flow behaviour of different W/D emulsions.