Emulsion characteristics media

A comprehensive review of the important factors that affect the flow of emulsions in porous media is presented with particular emphasis on petroleum emulsions. The nature, characteristics, and properties of porous media are discussed. Darcy s law for the flow of a single fluid through a homogeneous porous medium is introduced and then extended for multiphase flow. The concepts of relative permeability and wettability and their influence on fluid flow are discussed. The flow of oil-in-water (OfW) and water-in-oil (W/O) emulsions in porous media and the mechanisms involved are presented. The effects of emulsion characteristics, porous medium characteristics, and the flow velocity are examined. Finally, the mathematical models of emulsion flow in porous media are also reviewed. 

The scaling up or down of mixing systems with Newtonian rheological characteristics is comprehensively covered in the literature and in this book. However, the majority of emulsions with medium phase volume (30-55%) exhibit non-Newtonian behaviour. Literature is bereft of methods to scale up non-Newtonian systems. An approach is presented in Appendix 2 based on a generalized scale-up equation for agitated systems where ... 

Aqueous media, such as emulsion, suspension, and dispersion polymerization, are by far the most widely used in the acryUc fiber industry. Water acts as a convenient heat-transfer and cooling medium and the polymer is easily recovered by filtration or centrifugation. Fiber producers that use aqueous solutions of thiocyanate or zinc chloride as the solvent for the polymer have an additional benefit. In such cases the reaction medium can be converted directiy to dope to save the costs of polymer recovery. Aqueous emulsions are less common. This type of process is used primarily for modacryUc compositions, such as Dynel. Even in such processes the emulsifier is used at very low levels, giving a polymerization medium with characteristics of both a suspension and a tme emulsion. 

Abstract Emulsion homopolymers and copolymers (latexes) are widely used in architectural interior and exterior paints, adhesives, and textile industries. Colloidal stabihzators in the emulsion polymerization strongly affect not only the colloidal properties of latexes but also the fdm and mechanical properties, in general. Additionally, the properties of polymer/copolymer latexes depend on the copolymer composition, polymer morphology, initiator, polymerization medium and colloidal characteristics of copolymer particles. 

The characteristic K line consists of a closely spaced doublet with a 2 1 intensity ratio between the K i and K 2 lines. This not a problem if a low spatial resolution recording medium, such as a fluorescent screen and image intensifier, is used but is a problem if high resolution nuclear emulsion plates are used. Then individual dislocation images are doubled because the diffracted beams from the two lines make different directiorrs in space, giving rise to a type... 

Emulsion polymerization is usually carried out isothermally in batch or continuous stirred-tank reactors. Temperature control is much easier than for bulk or solution polymerization because the small ( 0.5 fim) polymer particles, which are the locus of the reaction, are suspended in a continuous aqueous medium. This complex, multiphase reactor also shows multiple steady states under isothermal conditions. In industrial practice, such a reactor often shows sustained oscillations. Solid-catalyzed olefin polymerization in a slurry batch reactor is a classic example of a slurry reactor where the solid particles change size and characteristics with time during the reaction process. 

Temperature Requirements of a Process. The temperature of filtration may affect the viscosity of the fluid, the corrosion rate of the housing, and filter medium compatibHity. Elevated temperatures tend to accelerate corrosion and may weaken the gaskets and seals of filter housings. In general, the viscosity of fluids decreases with increasing temperature. EHtration of highly viscous fluids maybe conducted at elevated temperature (8). For example, pharmaceutical products containing oil or a Hpid emulsion as a dmg carrier may require filtration at elevated temperature to enhance filterability characteristics. 

Effect of Porous Medium Characteristics. The characteristics of porous media such as average pore size and wettability play an important role in the flow of OAV emulsion through porous media. 

Effect of Porous Medium Characteristics. Several characteristics of the porous medium, including the average pore size, pore size distribution, and the wettability of the porous medium, can influence the flow of W/O emulsions. Very little information is available on these issues. The role of wettability is intuitively obvious. A water-wet medium would be more conducive to capture of the water droplets at pore walls. This capture facilitates formation of a free-water phase. An oil-wet medium, on the other... 

Homogeneous Models. The basic assumption in these models is that the emulsion is a continuum, single-phase liquid that is, its microscopic features are unimportant in describing the physical properties or bulk flow characteristics. It ignores interactions between the droplets in the emulsions and the rock surface. The emulsion is considered to be a single-phase homogeneous fluid, and its flow in a porous medium is modeled by using well-documented concepts of Newtonian and non-Newtonian fluid flow in porous media (26, 38). 

A critical review of emulsion flow in porous media has been presented. An attempt has been made to identify the various factors that affect the flow of OAV and W/O emulsions in the reservoir. The present methods of investigation are only the beginning of an effort to try to develop an understanding of the transport behavior of emulsions in porous media. The work toward this end has been difficult because of the complex nature of emulsions themselves and their flow in a complex medium. Presently there are only qualitative descriptions and hypotheses available as to the mechanisms involved. A comprehensive model that would describe the transport phenomenon of emulsions in porous media should take into account emulsion and porous medium characteristics, hydrodynamics, as well as the complex fluid-rock interactions. To implement such a study will require a number of experi-... 

In the preparation of microemulsions and self-emulsifying systems, emulsions, or aqueous suspensions of medium-chain triglycerides, care should be taken to avoid microbiological contamination of the preparation, since lipase-producing microorganisms, which become active in the presence of moisture, can cause hydrolysis of the triglycerides. Hydrolysis of the triglycerides is revealed by the characteristic unpleasant odor of free medium-chain fatty acids. 

Larger quantities of initial culture may be prepared in glass fermentation vessels each containing 10 liters of the same medium and inoculated with about 5 x 10 (to the) 9 (th) conidia. Incubation is continued for 3 days at 23° C. with aeration with 6 L. of air per minute and stirring at 200 r.p.m. In order to prevent foaming, a silicone emulsion is added. The fermentation cultures thus obtained have the same characteristics as the shake cultures. 

Elastic deformation also reveals itself in foams and concentrated emulsions. The shear stress in this case is determined by an increase in the interfacial area due to the deformation of the system. Mechanical properties of solidified foams and other solid-like cellular structures are governed by the degree of dispersion, type of backbone structure and a combination of mechanical characteristics of dispersed phase and dispersion medium. 

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