3,094 research outputs found
The twin-screw extrusion technology, an original and powerful solution for the biorefinery of sunflower whole plant
The objective of this study was to evaluate the feasibility of an aqueous process for the biorefinery of sunflower whole plant using a twin-screw extruder. Aqueous extraction of oil was chosen as an environment-friendly alternative to the solvent extraction. The extruder was used to carry out three essential unit operations: grinding, liquid/solid extraction, and liquid/solid separation. Wringing out the mixing was effective. However, drying of the cake meal was not optimal. Lixiviation of cotyledon cells was also incomplete. Extraction efficiency depended on operating conditions: screw rotation speed, and input flow rates of whole plant and water. In the best conditions, oil yield was 57%. Residual oil content in the cake meal was 14%. These conditions leaded to the co-extraction of proteins, pectins, and hemicelluloses. The corresponding protein yield was 44%. Oil was extracted in the form of two oil-in-water emulsions. These hydrophobic phases were stabilized by phospholipids and proteins at interface. An aqueous extract containing part of the water-soluble constituents, mainly proteins and pectins, was also generated. As a mixture of fibers and proteins, the cake meal was molded by thermo-pressing. Panels produced had interesting mechanical properties in bending. The obtained fractions may have applications as bases for industrial products
Direct extraction of oil from sunflower seeds by twin-screw extruder according to an aqueous extraction process: Feasibility study and influence of operating conditions
The objective of this study was to evaluate the feasibility of an aqueous process to extract sunflower seed oil using a co-rotating twin-screw extruder. Aqueous extraction was carried out using whole seeds and the influence of the operating conditions on oil yield was examined. Operating conditions included screw profile, screw rotation speed, and input flow rates of sunflower seeds and water. Liquid/solid separation required the addition of a lignocellulosic residue upstream from the filtration zone. However, even with maximum fiber input flow, drying of the cake meal did not improve. The lixiviation of the sunflower seeds was also incomplete. The aqueous extraction of the oil was more efficient in the twin-screw extruder than the reference trial conducted in a batch reactor. The best oil extraction yield obtained was approximately 55% and the residual oil content of the cake meal was approximately 30%. The hydrophobic phases produced were oil-in-water emulsions. These emulsions were stabilized by phospholipids and proteins at the interface, which are natural surface-active agents co-extracted during the process
Probing Mechanical Properties of Water-Crude Oil Interfaces and Colloidal Interactions of Petroleum Emulsions using Atomic Force Microscopy
Atomic force microscopy (AFM) is frequently used to elucidate complex interactions in emulsion systems. However, comparing results obtained with “model” planar surfaces to curved emulsion interfaces often proves unreliable, because droplet curvature can affect adsorption and arrangement of surface-active species, while droplet deformation affects the net interaction force. In the current study, AFM was used to study the interactions between a colloidal probe and water droplet. Force magnitude and water droplet deformation were measured in toluene solutions of asphaltene or bitumen at different concentrations and varying droplet aging time. Interfacial stiffening and an increase in particle–droplet adhesion force were observed upon droplet aging in bitumen solution. As reported in our previous study (Kuznicki, N. P., Harbottle, D., Masliyah, J., and Xu, Z.Dynamic Interactions between a Silica Sphere and Deformable Interfaces in Organic Solvents Studied by Atomic Force Microscopy. Langmuir 2016, 32 (38), 9797−9806), a viscoelasticity parameter should be included in the high-force Stokes–Reynolds–Young–Laplace (SRYL) equations to account for the interfacial stiffening and non-Laplacian response of the water droplet at longer aging times. However, following the addition of a biodegradable demulsifier, ethyl cellulose (EC), an immediate reduction in both the particle–droplet adhesion force and the rigidity of the water droplet occurred. Following EC addition, the interface reverted back to a Laplacian response and droplet deformation was once again accurately predicted by the classical SRYL model. These changes in both droplet deformation and particle–droplet adhesion, tracked by AFM, imply a rapid asphaltene/bitumen film displacement by EC molecules. The colloidal probe technique provides a convenient way to quantify forces at deformable oil/water interfaces and characterize the in situ effectiveness of competing surface-active species
Demulsification of O/W Emulsion by Weak Electrostatic Field(Poster session 1, New Frontiers in Colloidal Physics : A Bridge between Micro- and Macroscopic Concepts in Soft Matter)
この論文は国立情報学研究所の電子図書館事業により電子化されました。弱い静電場による水中油滴エマルションの解乳化 : 油滴表面に吸着したイオンによって安定化しているO/Wエマルションは,弱い電場を印加すると速やかに水相と油層に分離することを発見した。また,この現象が,油滴表面の電荷が電場によって移動したことによる,反発的電気2重層力の消滅により生じることを理論的に明らかにした
Acoustic interaction forces between small particles in an ideal fluid
We present a theoretical expression for the acoustic interaction force
between small spherical particles suspended in an ideal fluid exposed to an
external acoustic wave. The acoustic interaction force is the part of the
acoustic radiation force on one given particle involving the scattered waves
from the other particles. The particles, either compressible liquid droplets or
elastic microspheres, are considered to be much smaller than the acoustic
wavelength. In this so-called Rayleigh limit, the acoustic interaction forces
between the particles are well approximated by gradients of pair-interaction
potentials with no restriction on the inter-particle distance. The theory is
applied to studies of the acoustic interaction force on a particle suspension
in either standing or traveling plane waves. The results show aggregation
regions along the wave propagation direction, while particles may attract or
repel each other in the transverse direction. In addition, a mean-field
approximation is developed to describe the acoustic interaction force in an
emulsion of oil droplets in water.Comment: 11 pages, 5 eps figures, RevTex 4.
Aqueous extraction of oil from sunflower seeds in batch reactor: reorganization of the mixing in three formulated fractions
Aqueous extraction process is an alternative to the solvent oil extraction process from oilseeds. It enables simultaneous recovery of oil and protein. Water extraction of sunflower oil is carried out with a mixer (model Waring Blendor, USA) as batch reactor (seeds/water: 15/85). This only apparatus carries out two essential unit operations: conditioning and grinding of sunflower seeds and liquid/solid extraction. However, lixiviation of kernels is incomplete. After five minutes of extraction, the mixture reorganizes by centrifugation in three formulated fractions: the insoluble phase (31.1% of the mixture), the hydrophilic phase (61.4% of the mixture) and the hydrophobic phase (7.5% of the mixture). Oil extraction yield obtained is 46.6%. Residual oil content of raffinate is 39.2% instead of 49.7% in sunflower seeds. Aqueous extraction process also results in an impoverishment of oil cake into water-soluble substances contained initially in kernels: proteins and minerals. Raffinate is on the contrary richer in insoluble proteins and fibers (26.1% for cellulose and lignins instead of 17.1% in sunflower seeds). An additional stage of extraction would allow a better oil impoverishment of the insoluble phase before its possible use for animal feeding. It would be also possible to upgrade it by thermopressing. Panels obtained have mechanical characteristics comparable with those of other experimental materials. Hydrophilic phase is the dominating fraction. It contains proteins (31.8% of dry residue), minerals (8.2% of dry residue) and hemicelluloses. Its oil content means that centrifugation does not allow an expedient separation between hydrophilic phase and hydrophobic phase. After concentration of organic substances by ultrafiltration, it is possible to collect proteins by isoelectric precipitation. These water-soluble proteins can be used for their surface-active properties. Hydrophobic phase is an oil-in-water emulsion. It is lighter than hydrophilic phase (0.94 for its density). Lipids represent 83.8% of its dry residue. Its stability is ensured by the presence at interface of natural surface-active agents also extracted during the process, phospholipids and proteins. Demulsification is possible by alcoholic extraction. It enables the edible oil isolation. Oil consumption is possible for human feeding but also for non food uses like biolubricants market. Hydrophobic phase can also be used without any modification for the manufacture of paintings and cosmetics or for the treatment of surfaces with hydrophilic matter
Selective emulsion liquid membrane extraction of silver from photographic waste industries
The field of liquid membrane technology is currently undergoing a rapid expansion in research as well as its application as an industrial separation process.
Liquid membrane can be manipulated to selectively separate a specific solute from a mixture and even to extract a solute against its concentration gradient. A liquid membrane system comprises of three liquid phases; feed phase, liquid membrane organic phase and receiving phase. Liquid membrane can be prepared using support or as emulsion (unsupported) liquid membrane. Emulsion liquid membrane is a liquid membrane in which the membrane phase of an emulsion is dispersed into the feed phase to be treated. This method was investigated as an alternative process for the recovery of silver from photographic waste, which contains various metals ions such as silver, iron, sodium and potassium. The important parameters governing the extraction process of silver such as agitation speed, homogenizer speed, surfactant and carrier concentrations, type of diluents, treat ratio and types of stripping solution were investigated. This process has been conducted in a batch system using a mixer-settler. The results show that the mobile carrier Cyanex 302 is selective towards silver and almost completely extract silver over the other metals that existed in the photographic waste. The optimum silver extraction was obtained by using 0.03 M Cyanex 302, 3 % (w/v) Span 80, 250 rpm stirring speed, 1.0 M thiourea in 1.0 M H2SO4 stripping agent, 1:5 of treat ratio, and kerosene as a diluents. The experimental result also shows that the emulsion liquid membrane system could be recycled twice having 80% of silver was extracted. In addition, theoretical studies show that the developed model could predict the extraction performance of the system understudied as obtained from experimental data
Исследования влияния способов электроразрядного воздействия на агрегативную устойчивость высокоустойчивых эмульсий
Наведено результати експериментальних досліджень впливу способів електророзрядної дії на агрегативну стійкість високостійких водонафтових емульсій. Встановлено закономірності зв'язку параметрів дії зі зміною агрегативної стійкості емульсій.The results of experimental researches of influence of electric discharge methods on the demulsification of gravitational stability of highly stable water-oil emulsion are given. Conformities to the law of influence parameter association with the change of gravitational stability demulsification of emulsions are found
A Comparative Investigation on Petroleum Demulsification Techniques (Centrifuge and Green Chemicals Versus Conventional Chemicals)
The breaking (demulsification) of 50-50% w/o petroleum emulsions of two oils (A and B) by Green (chemical and centrifuge) methods were studied in comparison to conventional (chemical) method. The green methods consisted of silicon based chemical demulsifiers and high-speed centrifuge operated at 12,000 RPM, while the conventional method consisted of Amine group based demulsifiers. In chemical method, the concentrations were varied (0.5%, 1.5% and 3%), while in centrifuge method, the processing time was varied (10 and 30 minutes). The efficiency of these methods was determined by measuring the amount of water separated from the emulsion after being treated. The maximum separation efficiencies for Silicon demulsifiers were 93 and 88% for oils A and B respectively, and that of Amine group demulsifiers were 72 and 86% for oils A and B respectively, While centrifuge demulsification gave maximum separations of 39 and 24% for oils A and B respectively. Based on these results, Silicon based demulsifiers are very effective and reliable method to treat emulsions for different types of oils with different composition, and have the potential to be used as an alternative method in the demulsification or breaking of water-in-crude oil emulsions
Analysis of Microwave Heating Process for Demulsification of Water-in-Crude Oil Emulsions
In this investigation, the process of microwave heating technology was evaluated to measure the effect of some important parameters such as dielectric properties (έ and ɛʺ), rate of temperature increase (dT/dt), volume rate of heat generation (Qmw), wavelength (λ) and penetration depth (Dp) during the microwave irradiation on crude oil emulsions. Two types of Malaysian crude oil mixed together at a volume ratio of 50-50% and applied for further investigations. In order to ensure the efficiency of the process, the improvement of existing techniques and the development of new technology different ratios of water and oil were utilized to prepare the emulsions of water-in-crude oil (W/O). The emulsion samples were heated under 360 watt and 540 watt for 3 to 5 minutes. The findings of the microwave heating demulsification showed that higher microwave power (540 watt) along with the radiation time (5 min) were not much effective for water separation. This is because of the over boiling of the samples. Consequently, for microwave heating demulsification the best water separation efficiency was achieved at 3 (minutes), 360 (watt). Based on the result of microwave parameter’s calculations, it was found that parameters such as; dT/dt, Qmw, έ and ɛʺ, were inversely proportional to the radiation time. However, parameters such as λ and Dp were directly proportional to the time of the radiation
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