Multi-component liquids

In addition to the formation of single-component droplets in another liquid, multi-component droplets dispersed in another liquid may also be formed using microchannels. This process is schematically illustrated in Figure 25.12. Two... 

The calculation of vapor and liquid fugacities in multi-component systems has been implemented by a set of computer programs in the form of FORTRAN IV subroutines. These are applicable to systems of up to twenty components, and operate on a thermodynamic data base including parameters for 92 compounds. The set includes subroutines for evaluation of vapor-phase fugacity... 

Equation (4) is the )cey equation for calculation of multi-component vapor-liquid equilibria. 

Figure 4-20. Quarternary examples of three types of multi-component liquid-liquid mixtures.

When oil and gas are produced simultaneously into a separator a certain amount (mass fraction) of each component (e.g. butane) will be in the vapour phase and the rest in the liquid phase. This can be described using phase diagrams (such as those described in section 4.2) which describe the behaviour of multi-component mixtures at various temperatures and pressures. However to determine how much of each component goes into the gas or liquid phase the equilibrium constants (or equilibrium vapour liquid ratios) K must be known. 

Note that this equation holds for any component in a multi-component mixture. The integral on the right-hand side can only be evaluated if the vapor mole fraction y is known as a function of the mole fraction Xr in the still. Assuming phase equilibrium between liquid and vapor in the still, the vapor mole fraction y x ) is defined by the equilibrium curve. Agitation of the liquid in tire still and low boilup rates tend to improve the validity of this assumption. 

HGSystem offers the most rigorous treatments of HF source-term and dispersion analysis a ailable for a public domain code. It provides modeling capabilities to other chemical species with complex thermodynamic behavior. It treats aerosols and multi-component mixtures, spillage of a liquid non-reactive compound from a pressurized vessel, efficient simulations of time-dependent... 

Crystallization-based separation of multi-component mixtures has widespread application. The technique consists of sequences of heating, cooling, evaporation, dilution, diluent addition and solid-liquid separation. Berry and Ng (1996, 1997), Cisternas and Rudd (1993), Dye and Ng (1995), Ng (1991) and Oyander etal. (1997) proposed various schemes based on the phase diagram. Cisternas (1999) presented an alternate network flow model for synthesizing crystallization-based separations for multi-component systems. The construction... 

Richter, T., Ehrfeld, W., Hessel, V., Lowe, H., Storz, M., Wolf, A., A flexible multi component microreaction system for liquid phase reactions, in Ehrfeld, W. (Ed.), Microreaction Technology 3rd International Conference on Microreaction Technology, Proc. of IMRET 3,... 

Doherty MF and Perkins JD (1978) On the Dynamics of Distillation Processes I The Simple Distillation of Multi-component Non-reacting Homogeneous Liquid Mixtures, Chem Eng Sci, 33 281. 

Inductively coupled plasma atomic emission spectrometry (ICP-AES) is used to screen polymers, liquids and solvent extracts for residual metal atoms (catalysts, fillers, etc.). The technique can provide rapid multi-component screening of elements in solution over a wide concentration range (0.1-1,000 pg/ml). 

It is very difficult to cool pure metals and other pure elements fast enough to form glasses. However, metallic alloys can often be converted into glasses, particularly if they contain a mixture of small and large atoms such as iron and boron, or they are multi-component mixtures of metals that crystallize into more than one intermetallic compound (i.e., eutectic compositions). Thus, covalent chemical interactions of the atoms are important because they stabilize liquids and thereby inhibit crystallization. 

In multi-component liquids, stabilization of the liquid is revealed by the formation of eutectics where the freezing temperature is suppressed. In such liquids, the atomic species (say A and B) are not distributed at random. There are more associated AB pairs (or other clusters) than expected for a random distribution. As a result in binary metal-metalloid alloys, such as Fe-B, the low melting-point eutectics occur at preferential compositions. The most common of these is at about 17 at. % B, or an atom ratio of one B for five Fe atoms (Gilman, 1978). This suggests that clusters of metal atoms surrounding metalloid atoms form (trigonal bipyramids). These probably share corners, edges, and faces. 

The precise liquid-liquid equilibria (LLE) data is necessary to rational design of many chemical processes and optimize extraction processes. Many researchers have investigated various kinds of multi-component systems in order to understand and provide further... 

The UNIQUAC model was successfully used to correlate the experimental liquid-liquid equilibria data. As it can be seen from figure 1, the predicted tie lines (dashed lines) are in good agreement with the experimental data (solid lines). In other words, the UNIQUAC equations adequately fit the experimental data for this multi-component system. 

The more components in a system, the more complex are the phase equilibria and it is more difficult to represent phases graphically. Descriptions of multi-component solid-liquid diagrams and their uses have been given by Mullin 3, Findlay and Campbell , Ricci , Null(10) and Nyvlt 11 1 and techniques for predicting multi-component solid-liquid phase equilibria have been presented by Hormeyer et alS12 Kusik el al.(n), and Sander et al.(U). 

A melt is a liquid or a liquid mixture at a temperature near its freezing point and melt crystallisation is the process of separating the components of a liquid mixture by cooling until crystallised solid is deposited from the liquid phase. Where the crystallisation process is used to separate, or partially separate, the components, the composition of the crystallised solid will differ from that of the liquid mixture from which it is deposited. The ease or difficulty of separating one component from a multi-component mixture by crystallisation may be represented by a phase diagram as shown in Figures 15.4 and 15.5, both of which depict binary systems — the former depicts a eutectic, and the latter a continuous series of solid solutions. These two systems behave quite differently on freezing since a eutectic system can deposit a pure component, whereas a solid solution can only deposit a mixture of components. 

An equilibrium-flash calculation (using the same equations as in case A above) is made at each point in time to find the vapor and liquid flow rates and properties immediately after the pressure letdown valve (the variables with the primes F , F l, y], x j,.. . shown in Fig. 3.8). These two streams are then fed into the vapor and liquid phases. The equations describing the two phases will be similar to Eqs. (3.40) to (3.42) and (3.44) to (3.46) with the addition of (1) a multi-component vapor-liquid equilibrium equation to calculate Pi and (2) NC — 1 component continuity equations for each phase. Controller equations relating 1 to Fi and P to F complete the model. 

Sanz-Nebot, V., Benavente, R, and Barbosa, J. (2002). Liquid chromatography-mass spectrometry and capillary electrophoresis combined approach for separation and characterization of multi-component peptide mixtures — application to crude products of leuprolide synthesis.. Chromatogr. A 950, 99-111. 

All binding processes in real-life systems occur in some solvent. The solvent is, in general, a mixture of many components, including water electrolytes and nonelectrolytes. At present, it is impossible to account for all possible solvent effects, even when the solvent is pure water. Yet, the solvent, whether a single or multi-component, cannot be ignored. Any serious molecular theory of cooperativity must deal with solvent effects. We shall see in this chapter that this is not an easy task even when the solvent is inert, such as argon, or a simple hydrocarbon liquid. ... 

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