Binary systems classification

Glassification of Phase Boundaries for Binary Systems. Six classes of binary diagrams have been identified. These are shown schematically in Figure 6. Classifications are typically based on pressure—temperature (P T) projections of mixture critical curves and three-phase equiHbria lines (1,5,22,23). Experimental data are usually obtained by a simple synthetic method in which the pressure and temperature of a homogeneous solution of known concentration are manipulated to precipitate a visually observed phase. 

Data for the hydrogen sulfide-water and the methane-n-hexane binary systems were considered. The first is a type III system in the binary phase diagram classification scheme of van Konynenburg and Scott. Experimental data from Selleck et al. (1952) were used. Carroll and Mather (1989a b) presented a new interpretation of these data and also new three phase data. In this work, only those VLE data from Selleck et al. (1952) that are consistent with the new data were used. Data for the methane-n-hexane system are available from Poston and McKetta (1966) and Lin et al. (1977). This is a type V system. 

The situation in the solid state is generally more complex. Several examples of binary systems were seen in which, in the solid state, a number of phases (intermediate and terminal) are formed. See for instance Figs 2.18-2.21. Both stoichiometric phases (compounds) and variable composition phases (solid solutions) may be considered and, as for their structures, both fully ordered or more or less completely disordered phases. This variety of types is characteristic for the solid alloys. After a few comments on liquid alloys, particular attention will therefore be dedicated in the following paragraphs to the description and classification of solid intermetallic phases. 

In this section we will discuss the phase behaviour of binary systems. In 2.2.2.1 the classification of fluid phase behaviour according to van Konynenburg and Scott [5] is discussed. The occurrence of solid phases introduces an extra complication in binary phase phase diagrams. This is discussed in 2.2.2.2. 

No comprehensive geotechnical classification for pipeline construction in mountainous areas exists that could sufficiently address various aspects for the development of the binary system comprising the environment-and-pipeline . This would include quantitative and qualitative characteristics of both the environment and the facilities. 

A number of additional DTA experiments were undertaken with various compositions within the binary system up to 66.6 at. % S (= MoS2 composition). In Fig. 7 a phase diagram is shown in which all results are incorporated. With respect to the above-mentioned classification of sulfide systems14), the Mo—S system, as well as the Cr—S system, exhibits Type 1 two regions of immiscible liquids one field of liquid immiscibility in the metal-rich portion at high temperatures, and a second two-liquid field in the sulfur-rich region beyond MoS2 which is not shown in Fig. 7. 

Table 1 Classification of common aqueous and organic systems for polymer coacervation Binary systems Coacervation by partial polymer desolvation ...

In the light of these considerations, a different approach based on ternary system thermodynamics could be considered. However, the phase behavior of temaiy systems could be very complex and there is a considerable lack of data on ternary systems containing a component of low volatility therefore, a possible compromise could be to consider that the solute addition can produce the shift of the mixture critical point (MCP) (i.e., the pressure at which the ternary mixture is supercritical) with respect to binary system VLEs and the modification of this kind of system that is formed according to the van-Konynenburg and Scott classification. ... 

We shall now describe briefly some of the structures adopted by alloys. We shall limit our survey to binary systems. Adopting the classification of the elements indicated on p. 1008, we have to consider three main classes of alloys ... 

The analysis of nucleosynthesis in hypernovae suggests a possible classification scheme of supernova explosions [111]. In this scheme, core collapse in stars with initial main sequence masses Mms < 25 — 30M leads to the formation of neutron stars, while more massive stars end up with the formation of black holes. Whether or not the collapse of such massive stars is associated with powerful hypernovae ( Hypernova branch ) or faint supernovae ( Faint SN branch ) can depend on additional ( hidden ) physical parameters, such as the presupernova rotation, magnetic fields. [39], or the GRB progenitor being a massive binary system component [145, 117]. The need for other parameters determining the outcome of the core collapse also follows from the continuous distribution of C+O cores of massive stars before the collapse, as inferred from observations, and strong discontinuity between masses of compact remnants (the mass gap between neutron stars and black holes) [28]2. 

Table 6.1 Classification of the phases in the Ce02-Zr02 binary system.

Figure 6 is selected using the classification by Scott Konijnenburg (7), which describes only six different basic types of phase diagrams for binary systems. In Figure 4 a minimum can be observed at high pressure in the 70wt% fat isopleth, which corresponds to convergence of the isotherms in Figure 5. This is a clear indication of type III phase behavior, which is represented in Figure 6. A liquid-liquid phase split is in general typical for a type III system (9).

Figure 21.1.5 Classification of vapor-Uquid phase behavior of binary systems.

Fig. 4 shows schematic pTx diagrams (upper row) and the corresponding p T) projections (lower row) for a binary system here p = total pressure, T = temperature, x = mole fraction. Most important for the classification of fluid phase equilibria is the shape of the different critical curves. A critical curve connects all binary critical points in the pTx space here the two coexisting fluid phases become identical, namely at the extreme values of the isothermal p x) or isobaric T x) sections. Details can be found in the earlier publications [2-6,10,12]. 

In this section the first five types of fluid phase behavior according to the classification of Van Konynenburg and Scott [5,6] will be introduced. This classification for binary systems consists of six types of fluid phase behavior, of which originally the first five could be derived from the van der Waals equation of state [7]. Section 2.1 contains a description of the types I to V of fluid phase behavior. In addition, some possible transitions between the types II, III and IV are presented. In Section 2.2 the occurrence of type-I and -V fluid ph e behavior is discuss briefly. 

How important this argumentation is in practice should be decided fix>m case to case. For example, for the description of the fluid phase behavior of a certain binary system it might be convenient to say it shows type-V fluid phase behavior, i.e., above solidification. But a thorough understanding of the classification scheme is surely necessary for an analysis of transitions between different types of fluid phase behavior and other theoretical considerations. 

In addition, the binary system CO2 + 1-pentanol was examined more carefully. This binary system was earlier reported [41,42] to belong to type-II fluid phase behavior in the classification of Van Konynenbuig and Scott [14,30], see section 2, but was found here to show type-IV fluid phase behavior [19]. 

To obtain die systematic classification of complete phase diagrams for binary systems the method of continuous topological transformation was used (Valyashko, 1990a,b 2002a,b). This method is based on the following two main principles ... 

According to the classification of Scott and Konynenburg (1970, the binary systems of Type I, have only one critical locus between both critical points of the pure components and do not have the inuniscibility phenomena. For this type binary aqueous solutions, the functions Tc(x),pc(x), and Pc(x) were represented as simple polynomial forms (see Equations (2.65)-(2.67) of x and (1 - x) (Kiselev and Rainwater, 1997, 1998 Kiselev et al, 1998). Water -I- toluene system corresponds to a Type 111 mixture (Scott and Konynenburg, 1970), in which there is a three-phase immis-cibility region L1-L2-V with two critical endpoints (Li = V-L2 and Li = L2-V) where the VLE critical locus, originated in the critical point of pme more-volatile component (toluene) and the LLE critical locus, started in the critical point of less-volatile component (water), are terminated. 

In a gas fluidized bed where the bed particles are of different densities, it will be beneficial to know which component will sink (jetsam) and which will float (flotsam). In most cases, especially the two-component systems, the classification of flotsam and jetsam is obvious. In some isolated cases, whether the particular component will behave as a flotsam or a jetsam will have to be determined experimentally. This is especially true for a bed of multicomponent mixture with a wide size and density distribution. For a two-component binary system, Chiba et al. (1980) suggested the following general rules ... 

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