McCabe-Thiele diagram section

Fig. 3. A McCabe-Thiele diagram for a hypothetical square cascade section illustrating pinching. Terms are defined ia text.

Solution Constructed McCabe-Thiele diagram. Pinch found. (See Section 3 Fractionators Graphical Methods.)... 

The situation for any plate n, with liquid composition x corresponding to an equilibrium vapour composition y , but with actual vapour composition y , is represented on a small section of the McCabe-Thiele diagram in Fig. 3.62. 

When concentrations of the more volatile component of either product is very low the steps on the McCabe-Thiele diagram become very small and difficult to plot. This problem can be overcome by replotting the top or bottom sections to a larger scale, or on log-log paper. In a log plot the operating line will not be straight and must be drawn by plotting points calculated using equations 11.21 and 11.22. This technique is described by Alieva (1962) and is illustrated in Example 11.2. 

The concepts of section 8.5.1 are readily extended to determine the efficiency of a cascade. To illustrate this, the results of calculations identical to those of Tables 8.2 and 8.4, but with an 80% stage efficiency, are given in Table 8.8. The resultant McCabe-Thiele diagram is given in Fig. 8.11. 

Figure 13 shows a McCabe-Thiele diagram, which can be used when the mixture to be distilled consists of only two components or can be represented by two components. Starting at the required overhead product composition x/), an upper-section operating line is drawn hav-... 

The test separation data are analyzed using a McCabe-Thiele diagram (Fig, 7.12a), with an equilibrium curve based on experimental data (average relative volatility of about 1,7), The analysis shows that the stripping section requires 12 theoretical stages. 

The efficiency of real contacting stages can be accounted for by reducing the height of the steps on the McCabe-Thiele diagram see Figure 11.6. Stage efficiencies are discussed in Section 11.10. 

The extiacting-section operating line shown in the McCabe-Thiele diagram of Fig. 4.15 passes throi the point (yo, xf) and has the slope (S + F) E. 

The operation of a batch still and column can be analyzed using a McCabe-Thiele diagram, with the same operating-line equation that was used for the rectifying section of a continuous distillation ... 

In order to correct the situation, it is proposed to add an intercondenser in the rectifying section to generate more reflux and an interreboiler in the stripping section to produce additional boilup. Show by use of a McCabe-Thiele diagram how such a proposed change can improve the operation. 

Fig. 5.9 shows the geometric representation of these balances in the McCabe-Thiele diagram. The distillate composition xP is located at the intersection of the condenser operating line and the operating line of the RD section. By specifying xP, the number of reactive trays can be estimated from the classical staircase construction. From the intersection of the operating line of the column section with that of the reboiler line, the bottom composition is determined. 

McCabe-Thiele graphical method. The equations obtained in the preceding section can be represented graphically on a McCabe-Thiele diagram. The operating lines, equations 7.6.7 and 7.6.8, are plotted on x-y coordinates along with the equilibrium line, which is the locus of equilibrium (x, y) compositions. The latter are obtained from tabulations or equations like 7.6.6. 

Since the column shown in Figure 4-23A has four sections, there will be four operating lines. This is illustrated in the McCabe-Thiele diagram of Figure 4-23B. One would specify that the liquid be withdrawn at flow rate S at either a specified concentration Xg or a given stage locatiom The saturated vapor is at concentration yg = Xg. Thus there is a horizontal feed line at yg. If the optimum location for... 

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