Coordinates, Janecke

Figure 14.1. Equilibria in a ternary system, type 1, with one pair of partially miscible liquids A = 1-hexene, B = tetramethylene sulfbne, C = benzene, at 5(TC (JR.M. De Fre, thesis, Gent, 1976). (a) Equilateral triangular plot point P is at 20% A, 10% B, and 70% C. (b) Right triangular plot with delines and tieline locus, the amount of A can be read off along the perpendicular to the hypotenuse or by difference, (c) Rectangular coordinate plot with tieline correlation below, also called Janecke and solvent-free coordinates.

Calculated ratios for the Janecke coordinate plot of Figure 14.1 ... 

Evaluation of the numbers of stages also can be made on rectangular distribution diagrams, with a McCabe-Thiele kind of construction. Example 14.5 does this. The Janecke coordinate plots like those of Figures 14.1 and 14.2 also are convenient when many stages are needed, since then the triangular construction may... 

Naturally, the latter constructions are analogous to those for distillation since their forms of equilibrium and material balances are the same. References to the literature where similar calculations are performed with Janecke coordinates were given earlier in this section. 

Triangular diagrams, such as Fig. 10.5-1, can be uned to cany am equilibrium-stage leaching calculations in the same way that analogous calculations are ceiried out for ternary liquid-liquid extractions.1 3 Other coordinate systems, for example, Janecke coordinates, can also be used for such calculations. 

To construct and use a Ponchon diagram for extraction problems it is convenient to consider the solvent in extraction as analogous to enthalpy in distillation. Thus, the solvent-free extract phase in extraction becomes analogous to the enthalpy-rich vapor phase in distillation, as discussed by Smith. Similarities between the two processes are noted in Table 10.2. The most important difference is the choice of coordinates. In Fig. 10.21, Janecke coordinates, as described in Chapter 3, are used. The abscissa is on a solvent-free basis A/(A -I- C) and the ordinate is S/(A -I- C). Thus, the coordinates of pure solvent are at A = 0, Y = infinity, and the flows L and V are solvent free. 

Odier representatioas of eqnilibiinm data are in common use. For example, a Hand plot b often attractive as well as distribotion dragrams and the use of other coordinate systrans (e.g., rectarfy alar or Janecke coordinates). Since the use of these systems has been described in detail dsewhere, they simply are mentioned here. 

Janecke Diagram. This system of coordinates, described in Chap. 2, involves plotting X, the weight fraction of (7 on a 5-free basis as abscissa against N, the weight of B per unit weight of B-free solution as ordinate, as in Fig. 6.26. Thus,... 

On the Janecke diagram, as on triangular coordinates, if a mixture at 0 is added to one at P, the resulting mixture K will be on the straight line OPy and the weights are in the follow ing relationship ... 

Fig. 6.10. Single-contact extraction and solvent recovery on Janecke coordinates.

Eng. Chem. 33,1240 (1941)]. Calculations will be made on triangular and Janecke coordinates. 

Janecke Diagram. Construction on these coordinates is indicated in Fig. 6.21, which also includes the solvent-recovery lines. Calculations again are simply an extension of the case for single contact, Eqs. (6.30) to... 

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