Mixing performance Emulsions

Mixing performance, 306 Blending, 324 Emulsions, 324 Extraction, 324 Gas-liquid contacting, 324 Gas-liquid dispersion, 325 Liquid-liquid dispersion, 325, 326 Mixing vortex, 311 Motionless mixing, see static mixing National Fire Protection Association, 399 Net positive suction head, 160-194 Available from system, 160, 188, 189,... 

An emulsion is a biphasic solution including dispersed small oil droplets in an aqueous phase. Because of the small channel size and high fluid velocity in micromixers, high shear force is applied to fluids, resulting in the generation of an emulsion in addition to enhancement of the mixing performance. The emulsion produced using micromixers has the characteristics of stability without surfadant. 

A dispersion is instead a mixture in which the less abundant compound is dispersed, but not molecularly dissolved, in the other component. Examples are a dispersion of a solid phase (powder, nanoparticles, nanocrystals, nanotubes, etc) in a solvent, which is called a suspension, or a dispersion of an immiscible liquid phase in a second liquid, which is called an emulsion. Milk and mayonnaise are familiar examples of emulsions. Aerosols are dispersions of tiny liquid droplets or solid particles in a continuous gaseous phase. The science of aerosols is particularly relevant in order to design filter elements able to remove droplets and particles from air, which can be performed with very high efficiency by polymer nanofibers (Section 4.3.1). Finally, another way to indicate homogeneously mixed dispersions, emulsions or aerosols of nano- or microparticles is colloids. Colloidal dispersions of inorganic nanocrystals or organic nanofibers are familiar examples for nanotechnologists. 

A variation of this process uses an emulsified bitumen product that is miscible with a wet sludge. In this process, the mixing can be performed at any convenient temperature below the boiling point of the mixture. The overall mass must still be heated and dried before it is suitable for disposal. Ratios of emulsions to waste of 1 1 to 1 1.5 are necessary for adequate incorporation. 

Values for the various parameters in these equations can be estimated from published correlations. See Suggestions for Further Reading. It turns out, however, that bubbling fluidized beds do not perform particularly well as chemical reactors. At or near incipient fluidization, the reactor approximates piston flow. The small catalyst particles give effectiveness factors near 1, and the pressure drop—equal to the weight of the catalyst—is moderate. However, the catalyst particles are essentially quiescent so that heat transfer to the vessel walls is poor. At higher flow rates, the bubbles promote mixing in the emulsion phase and enhance heat transfer, but at the cost of increased axial dispersion. 

The Kies extraction apparatus4 is useful in minimizing emulsion formation. The checkers performed the countercurrent extractions successfully in separatory funnels. The solutions must be mixed by mild rocking of the funnels otherwise serious emulsions will be produced. 

Dehydration experiments were performed with emulsions containing 201 water. The emulsions were formed by mixing crude and formation water for two minutes at the anticipated wellhead temperature of 66° C in a high speed blender. The demulsifier was added and dispersed in the emulsion by an additional 10 second mixing prior to transfer Into dehydration bottles which were heated In a water bath set at the desired temperature. 

Hydraulic Behavior. The influence of the main DMDOHEMA degradation products on the hydraulic performances of the process flowsheet was investigated by the determination of the emulsion settling time after mixing the irradiated solvent with nitric acid solution (0.1 mol I. ). This settling time increased with the irradiation dose. Experiments performed with synthetic solutions of monoamide and... 

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