McCabe-Thiele plots

There are two more such series lines to input with their respective data points. Again, use trial and error to determine the one data point for each step, using the McCabe-Thiele plot as in Example 7.1. After installing the last series line, your McCabe-Thiele plot should be as shown in Fig. 7.9. 

Figure 11.8. McCabe-Thiele Plot for Two Binary Mixtures...

Vapor-liquid equilibrium is a mapping from a liquid composition to a vapor composition. It can be done by including tie lines from one to the other for all compositions. On a line, such a mapping is very difficult to visualize, so we typically use a second dimension where we can plot vapor composition versus liquid composition as in a McCabe-Thiele plot or as in a temperature versus composition diagram. For three or four species, showing tie lines is fairly direct. The important point is that equilibrium is not a line (as we might think because of our familiarity with McCabe-Thiele plots) but a mapping. 

The McCabe-Thiele plot is drawn on Figure 3.31. Note that the scales are different on each axis, based on the equilibrium relationship and operating-line coordinates. 

If the operating line was not a straight line on a McCabe-Thiele plot, could you still use the methodology to determine the number of equilibrium stages Justify your answer. 

FIGURE 12.11 Modified McCabe-Thiele plot to show approach to equihbrium on real stages. The relative height of the real stage to the equilibrium stage height denotes Murphree stage efficiency. 

The same procedure used to establish the pseudoequilibrium line on the McCabe-Thiele plot can be used in conjunction with the Ponchon method. If the Murphree efficiency is constant, a pseudoequilibrium curve could be drawn through y n and other points identically. This line AB, in conjunction with the difference points, could be used to step off stages. 

Effect of Q/A Phase Ratio on the Extraction of Metal Ions. Extraction of Co from Ni was carried out at different 0/A ratio using 5% PC88A + 2% Cyanex 272 (70% Saponified) at initial aqueous pH of 4 to obtain optimum condition. The result shows (Fig-4) that on increasing 0 A ratio, the percentage extraction of Co increases. The McCabe Thiele plot represented in Fig. 5 shows the requirement of 2 stages for the complete extraction of cobalt at 0 A =1 1. 

Under equilibrium extraction condition the solvent mixer was loaded in a two stage continuous counter current mode as determined by McCabe Thiele plot using O/A phase ratio of 1 1 (Fig. 5). The raffinate contains only 11 ppm of cobalt along with 30.3 g/L Ni. The loaded organic... 

Figure 5. McCabe-Thiele plot for the stage determination for Co extraction with solvent 5% PC 88A+2%Cyanex 272, Aqueous feed 30.86g/L Ni, 3.6g/L Co.

McCabe-Thiele plot for a tower with a liquid side stream above the feed. 

Figure 8.5. McCabe-Thiele plots for all components of a ternary mixture under minimum reflux for the preferable split. Operating (solid) and equilibrium (dotted) lines for parts of column — a,b,c,d. (b) Parts of column a,b,c,d and pinches i xp 2, f,3,...

Figure 8.1.25. (a) Distillation column with open steam injection at the bottom instead of a reboiler (b) the corresponding McCabe-Thiele plot. 

Figure 8.1.32. (a) Packed tower continuous contact distillation column, (b) McCabe-Thiele plot of operating lines in a packed tower... 

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