Immiscible process equipment

The separation of components by liquid-liquid extraction depends primarily on the thermodynamic equilibrium partition of those components between the two liquid phases. Knowledge of these partition relationships is essential for selecting the ratio or extraction solvent to feed that enters an extraction process and for evaluating the mass-transfer rates or theoretical stage efficiencies achieved in process equipment. Since two liquid phases that are immiscible are used, the thermodynamic equilibrium involves considerable evaluation of nonideal solutions. In the simplest case a feed solvent F contains a solute that is to be transferred into an extraction solvent S. 

It is common to distinguish between internal and external lubricants. The worst definition is based on who adds the lubricant if the supplier added it, it comes to the processor as an internal lubricant if the processor must add it himself, it is an external lubricant. A semimeaningful distinction an internal lubricant is compounded into the polymer an external lubricant is applied to the surface of the mold. The proper distinction is based on miscibility/immiscibility of the additive in the polymer an internal lubricant is miscible with the polymer and acts like a small amount of plasticizer to increase molecular flexibility and mobility, and to help the disentanglement and flow of tbe polymer molecules in the melt. An external lubricant is immiscible in the polymer and tends to exude to the surface of the plastic and form an abhesive (nonstick) interface between the polymer and the steel process equipment, or it tends to come to the surface of the finished plastic product and give it continual lubricity in the use of the product. 

Design Scope. Stirred vessels, rotor-stator mixers, static mixers, decanters, settlers, centrifuges, homogenizers, extraction colunms, and electrostatic coalescers are examples of industrial process equipment used to contact liquid-liquid systems. Although this chapter emphasizes stirred vessels, the fundamentals of phase behavior are applicable to a broad range of other equipment types. Immiscible liquid-liquid systems are processed in batch, continuous, and semicontinuous modes. 

Since the processing conditions and mixing equipment have a crucial effect on the morphology of immiscible polymer blends [45], experiments were carried out in four different types of extruders to find optimal conditions for blend preparation and fibrillation. Nevertheless, the morphologies of PP-LCP blends produced by... 

Separation of two liquid phases, immiscible or partially miscible liquids, is a common requirement in the process industries. For example, in the unit operation of liquid-liquid extraction the liquid contacting step must be followed by a separation stage (Chapter 11, Section 11.16). It is also frequently necessary to separate small quantities of entrained water from process streams. The simplest form of equipment used to separate liquid phases is the gravity settling tank, the decanter. Various proprietary equipment is also used to promote coalescence and improve separation in difficult systems, or where emulsions are likely to form. Centrifugal separators are also used. 

Sample integrations similar to pharmaceutical approaches were already examined in 1997 [39]. Here, a chip-like microsystem was integrated into a laboratory automaton that was equipped with a miniaturized micro-titer plate. Microstructures were introduced later [40] for catalytic gas-phase reactions. The authors also demonstrated [41] the rapid screening of reaction conditions on a chip-like reactor for two immiscible liquids on a silicon wafer (Fig. 4.8). Process conditions, like residence time and temperature profile, were adjustable. A third reactant could be added to enable a two-step reaction as well as a heat transfer fluid which was used as a mean to quench the products. 

Conventional liquid-liquid extraction is an established unit operation for transferring one or more solutes from a solution into a second, immiscible liquid. It is widely used for separating ionic and nonionic species, for example, on the basis of their preferential partitioning between an aqueous phase and a nonaqueous phase, respectively. Industrial liquid-liquid extraction equipment generally consists of a mixer, where the feed solution and the extractant liquid are intimately mixed via agitation, and a settler where the equilibrated phases are separated for further processing. 

SOLVENT extraction (liquid-liquid extraction) is the separation and/or concentration of the components of a solution by distribution between two immiscible liquid phases. A particularly valuable feature is its power to separate mixtures into components according to their chemical type. Solvent extraction is widely used in the chemical industry. Its applications range from hydrometallurgy, e.g., reprocessing of spent nuclear fuel, to fertilizer manufacture and from petrochemicals to pharmaceutical products. Important factors in industrial extraction are the selection of an appropriate solvent and the design of equipment most suited to the process requirements. 

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