Solid-liquid-vapor interactions

Solid-Liquid-Vapor Interactions in Alkali-Rich Coal Slags... 

COOK AND HASTIE Solid-Liquid- Vapor Interactions in Slags... 

The presence of multiple components adds a new dimension to the phase behavior of mixtures. In the pure component, molecules are always surrounded by similar species in a mixture, they are surrounded by both like and unlike species. This gives rise to self-interactions between like molecules, and crossinteraction between unlike molecules. These interactions are much more pronounced in the liquid phase, where molecules are closely packed together. The balance of self- and cross-interactions creates phase behavior that is not seen in pure fluids. If cross-interactions are favorable, components form strong mixtures that are more difficult to separate. If cross interactions are unfavorable, the mixture is weaker and separation is easier. If they are strongly unfavorable, then components may exhibit partial miscibility. Additional variety of phase behaviors comes from the number of phases that can coexist simultaneously. With mixtures we encounter problems of vapor-liquid equilibrium (VLE), but also liquid-liquid (LLE) and liquid-liquid-vapor (LLVE) equilibrium. If a solid component is added, other combinations of equilibria are observed for example, solid-liquid, solid-liquid-vapor, etc. This enormous variety is made possible by the presence of additional components. 

With the critical exponent being positive, it follows that large shifts of the critical temperature are expected when the fluid is confined in a narrow space. Evans et al. computed the shift of the critical temperature for a liquid/vapor phase transition in a parallel-plates geometry [67]. They considered a maximum width of the slit of 20 times the range of the interaction potential between the fluid and the solid wall. For this case, a shift in critical temperature of 5% compared with the free-space phase transition was found. From theoretical considerations of critical phenomena... 

The choice of the size parameter d is somewhat ambiguous since even the relative values of d vary somewhat between solid, liquid, and gaseous salts because of the influence of interactions other than those represented by Eq. (7). For the case of a change of phase or for the description of phenomena where the environment of the ions changes drastically (as in the discussions of vapor pressure and surface tension), the influence of these other interactions is relatively large and other characteristic thermodynamic parameters (such as the melting temperature), which at least partly reflect these other interactions, should lead to more realistic relationships. Where there is no drastic change... 

An important example of a repulsive van der Waals force is the force between a solid particle interacting in water with an air bubble. This is a typical situation in flotation, where air bubbles are used to extract mineral particles from an aqueous dispersion (see Section 7.6.1). For some materials the van der Waals force between the solid-liquid and the liquid-vapor... 

A fundamental account of unsteady motion in a dense suspension requires knowledge of phase interactions and origins of wavy stratified motion [Zhu, 1991 Zhu et al., 1996]. Flow stratification involves a dense phase of solids flowing along the bottom of a horizontal pipe with wave motions, or a layer of the dense phase of solids flowing near the wall of a vertical pipe with wave motions. The former was analyzed, in part, on the basis of the theoretical work of de Crecy (1986) on stratified liquid-vapor flows. 

Two-phase flow concerns the interacting flow of two phases involving mixtures of solid/liquid, solid/gas, gas/liquid. The interface between the phases is affected by the motion of the phases. In general, two-phase flow consisting of liquid/gas (or vapor) can be considered to be the most common in the processing industries. 

These three approaches have found widespread application to a large variety of systems and equilibria types ranging from vapor-liquid equilibria for binary and multicomponent polymer solutions, blends, and copolymers, liquid-liquid equilibria for polymer solutions and blends, solid-liquid-liquid equilibria, and solubility of gases in polymers, to mention only a few. In some cases, the results are purely predictive in others interaction parameters are required and the models are capable of correlating (describing) the experimental information. In Section 16.7, we attempt to summarize and comparatively discuss the performance of these three approaches. We attempt there, for reasons of completion, to discuss the performance of a few other (mostly) predictive models such as the group-contribution lattice fluid and the group-contribution Flory equations of state, which are not extensively discussed separately. 

The catalytic properties of Au depend markedly on the preparation method, because it can bring about a large difference in the size of Au particles and the interaction with supports. Until now six methods, including solid-, liquid-, anH vapor-phase techniques, have proven effective for preparing active gold catalysts. 

Trimethylaluminum exists as a dimer in solid, liquid and vapor phase and in nonpolar solvents. However, the active species is the monomeric form. The methyl halide solvent helps to break up the methyl bridge of the Me3Al dimer enabling the t-butyl halide to interact with the alkylaluminum to generate the initiating f-Bu ion (13). Kinetic analysis... 

The thickness of adsorbed layers depends on the extent of molecular interactions, but usually films of one molecule thickness, which are called monolayers, form at the liquid-vapor and liquid-liquid interfaces upon adsorption. In gas adsorption on solids, several molecular layers, which are called multilayers, form at high pressures, and mono-layers can only be formed if the gas pressure is sufficiently low. If van der Waals forces are operative during the adsorption process, it is called physical adsorption or physiosorption (see Section 8.3.1), whereas if chemical bonds are formed during the adsorption process, then it is called chemical adsorption or more preferably chemisorption (see Section 8.3.2). 

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