Janecke diagram

Figure 4 Janecke diagram for the reciprocal salt pair KCl-NH. Oj in water. Calculated two-salt saturation lines and experimental two-salt saturation points...

Figure 7.18 Use of Janecke diagram with auxiliary distribution curve for countercurrent extraction with reflux.

Equilibrium data (Boobar, et al. 1951) have been converted to a solvent-free basis and are given in Table 7.4 (Treybal, 1980). These are plotted in the form of a Janecke diagram in Figure 7.19. The corresponding equilibrium distribution diagram is Figure 7.20. From the problem statement, F =F= 1000 kg/h, XF - 0.6 wt fraction of styrene,... 

Generate the Janecke diagram and the distribution curve for the system cottonseed oil (A)-propane (B)-oleic acid (C) at 372 K and 42.5 atm. 

If 100 kg of a cottonseed oil-oleic acid solution containing 25 wt% acid is extracted twice in crosscurrent fashion, each time with 1000 kg of pure propane, determine the compositions (wt%) and the weights of the mixed extract and the final raffinate. Make the computations on a solvent-free basis using the Janecke diagram generated in Problem 7.17. 

A feed mixture containing 50 wt% n-heptane and 50 wt% methylcyclo-hexane (MCH) at 298 K and 1 atm flows at a rate of 100 kg/h and is to be separated by liquid-liquid extraction into one product containing 92.5 wt% MCH and another containing 7.5 wt% MCH (both on a solvent-free basis). Aniline will be used as the solvent. Using the equilibrium data given in Table 7.8 to construct a Janecke diagram, calculate ... 

It should be noted that on the Janecke diagram M V /ML does NOT equal LJVi it equals the ratio of LilVi on a solvent free basis. 

In order to simplify the interpretation of the phase equilibria in reciprocal salt pair systems, the water content may be excluded. The curves of the space model can then be projected on to the square base to give a two-dimensional graph, called a Janecke diagram as described in section 4.7.1. A typical projection is shown in Figure 4.31a the lettering is that used in Figure 4.30. The enclosed areas, which represent saturation surfaces, indicate solutions in equilibrium with one salt, the curves solutions in equilibrium with two salts, points P and Q solutions in equilibrium with three salts. 

Figure 4.32 shows Janecke diagrams for solutions of a given reciprocal salt pair at different temperatures. These two simple cases will be used to demonstrate some of the phase reactions that can be encountered in such systems. Both diagrams are divided by the saturation curves into four areas which are actually the projections of the surfaces of saturation (e.g., see Figure 4.32b). Salts AX and BY can coexist in solution in stable equilibrium the solutions are given by points along curve PQ. Salts BX and however, cannot coexist in solution because their saturation surfaces are separated from each other by curve PQ. Thus AX and BY are called the stable salt pair, or the compatible salts, BX and A Y the unstable salt pair, or the incompatible salts. In Figure 4.32a the AX-BY diagonal cuts curve PQ which joins the two quarternary invariant points, while in Figure 4.32b curve P Qj is not cut by either diagonal. These are two different cases to consider.

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 ... 

Janecke Diagram. Calculations for the flowsheet of Fig. 6.4 can be followed on the Janecke diagram if it is recalled that the B-free weights of the various streams are F, S, E,... 

Janecke diagram. The greatest value of Xc on the binodal curve at Q is 0.840. This corresponds to 84.0% acetone. Ans. 

Janecke diagram. The tie line through G gives Xcij = = 0.005, corresponding to... 

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... 

The Janecke diagrams for both of the cases just described are obvious from the description of the triangular coordinate construction and need no additional explanation. See also the following illustration. 

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