Operating fines

Tie lines tie together corresponding concentrations on the operating line (bulk concentrations) and the equilibrium line (interfacial concentrations). The tie line slope is determined from the final equality for TLS in Eq. (11.31). The values of Hg and Hi are the average values determined in step 5 (1.34 ft and 0.82 ft, respectively). The value of L M/G M was determined in step 3 (3.91). Various tie lines are to be constructed over the entire concentration range covered by the operating line. A particular tie line will cross the operating fine atx and y, the values of which are used in Eq. (11.31) to calculate yBm and xBM, and in the equation for TLS. 

The graphical interpretation of Eq. (16-199) is shown in Fig. 16-37 for the conditions of Example 16-14. An operating line is drawn from the origin to the point of the pure displacer isotherm at Ci = cf. For displacement to occur, the operating fine must cross the pure component isotherms of the feed solutes. The product concentrations in the isotachic train are found where the operating line crosses the isotherms. 

Figure 12.4 Top Illustration of the watershed point. Same experimental conditions as in Figxue 12.1b, except Q and sample size, (a) Displacement chromatogram with a displacer concentration at the watershed point of the first component, Q = 85 mg/mL. Sample sizes 50, 50, and 100 mg. (b) Same conditions as in (a), except sample sizes 50, 25, and 50 mg. Bottom Illustration of the watershed point. Same experimental conditions as in Figures 12.1b and a above, except Q and sample size, (c) Illustration of the isotherms and the operating fine for (b). (d) Displacement chromatogram with a displacer concentration at the watershed point of the second component, Q = 46.4 mg/mL. Sample sizes 50,25, and 50 mg.

The HCR s have the advantage over control splines in that t.l ey are remotely operable. Fine adjustments in position can be made during all periods of reactor operation and the rod position is indicated in the control room at all times. The control rods have a relatively long lile, but repair or replacement can be a time consuming and expensive operation. 

A modern commercial mass spectrometer will incorporate a computer or will offer a facility to communicate with a computer via a data link, for example, to a plant control system using serial, ethernet or analog, and/or digital signals. This allows data to be stored and manipulated, often in real-time , so that results can be displayed to the user in a convenient form or to be utilized for process control either automatically via a closed loop or for operator fine-tuning . A mass spectrum may be displayed as a continuous scan over a specified mass range similar to a strip-chart, but this is difficult to interpret, and is not directly quantitative. 

For the reversible distillation, the operation fine should coincide with the equilibrium line for the binary mixture in the McCabe-Thiele diagram. 

Where are the operating fines of the process opposite to the process of distillation in the diagram of McCabe and Thiele located ... 

The compositions of the products are read from the intersections of the operating fines with the diagonal. The results are tabulated in Table 6.2 for different reflux ratios. Also shown are the condenser and reboiler temperatures as read from Figure 6.3, and the product flow rates, calculated from a component... 

By contrast, the stripping section of the column is quite stable since the operating fine in that section is a good distance from the equilibrium curve. Lowering or raising reflux ratio by reasonably small amounts causes minor changes in the bottoms composition. 

The stepped stages may be altered slightly if the operating fines are redrawn based on a side draw composition of 72% instead of the original 74% mole acetone. Alternatively, the reflux ratio may be adjusted such that the liquid draw from the third stage has a composition of 74% acetone. The steps necessary for this approach are as follows ... 

For the given values of = 0.94 and X = 0.74, draw the top operating fine with a slope that results in three stages between X and X. ... 

In general, when the operating fine and equilibrium curve are not straight, the number of transfer units must be determined by numerical or graphical integration of Equation 15.3 or 15.5 or other equivalent form of these equations. 

The size of the yeast population should always be taken into account to evaluate the effectiveness of a sulfiting. All operations (fining and filtration) that eliminate a fraction of the yeasts permit the lowering of the free SO2 concentration necessary for conserving sweet wines. 

The operating fine of minimum slope is the operating line that just touches the equihbrium fine at... 

This differs from Eq. (11.19) for dilute solutions only by the ratio of yau to xbu- Based on the average values, Hg/Hi = 1.34/0.82 = 1.634. Values of the other quantities in Eq. (11.32) vary over the tower. X is the ratio of the slope of the equilibrium fine to that of the operating line. Values of X can be obtained directly from the operating diagram by determining the slope of the operating fine at one end of a particular tie line and the slope of the equilibrium line at the other end of the same tie line. Values of xbm and ysu can be determined with the values of x and x,- and y and yi at either end of the same tie fine. 

We begin with the case of a saturated Hquid feed. Such a feed does not change the vapor flow up the column it only alters the liquid flow down the column. In other words, G equals G and L equals L + F) where F is the feed per time per column cross-section. This means that the slope of the operating fine must change at the feed point, from LjG) to ((L + F)/G). 

Thus, in the upper rectifying part of the column, LA and GA are 3330 and 4730 mol/hr, respectively. The operating fine for this region is found from Eq. 12.4-1 ... 

This result, called the operating fine of the stripping section, is also important and will be used later. Note that in contrast to the rectifying section, a plot of i versus x in the... 

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