Relative volatility definition

Since the overhead composition xD is the one that is specified rather than that of the liquid on the top tray, x, the latter is eliminated from Eq. (13.94). The relative volatility definition is applied... 

As an example of how the approximate thermodynamic-property equations are handled in the inner loop, consider the calculation of K values. The approximate models for nearly ideal hquid solutions are the following empirical Clausius-Clapeyron form of the K value in terms of a base or reference component, b, and the definition of the relative volatility, Ot. 

Definition of Relative Volatility Relative Volatility of Component 1 with respect to component 2. 

From the definition of the volatility of a component, it is seen that for an ideal system the volatility is numerically equal to the vapour pressure of the pure component. Thus the relative volatility a may be expressed as ... 

In a more comprehensive study, 46 constituents were identified in the interdigital secretion of the white-tailed deer, 0. virginianus [129]. Only relatively volatile compounds up to methyl salicylate were identified in the secretion, because samples for GC-MS analysis were enriched from the headspace gas of the secretion collected on cotton swabs. Some variations in the relative concentrations of the compounds between the secretions from dominant and subordinate animals were observed, but it was not possible to conclude definitely whether these differences were related to age or dominance. 

The definition of relative volatility, Eq. (13.14), is rearranged into this form ... 

Distillation is a technique of separating components according to their relative volatility, The relative volatility is a measure of the ease of separation. This definition makes the relative volatility the ratio between the tendency to vaporize of the two components. If relative volatility is high, one component has a much greater tendency to vaporize (i.e., is more volatile) than the other, and it will be easy to separate the two by vaporizing one from the other (i.e., by distillation), On the other hand, when one component has as high a tendency to vaporize (i,e, is as volatile) as the other, relative volatility will approach unity, and the components will he difficult to separate from each other by distillation, If relative volatility is unity, each component is as volatile as the other, and they cannot be separated by distillation. 

For the purpose of this discussion, Eq. (1.11) is simplified by omitting the Poynting correction, which is usually small at low pressures. Combining Eq, (1.11) with the definition of relative volatility, Eq. (1,2) gives... 

The ratio of Jif-values is an exact definition for relative volatility. The ratio of vapor pressures is an approximate one that assumes Raoult s law holds, thereby assuming that the Ar-values are not composition-dependent. The advan-... 

For quick estimates, a relative volatility can be esti- By definition mated as follows ... 

Step 2 Calculate the corresponding y. Recalling the definition of relative volatility (see page 51) ... 

The y-coordinatc of this point is determined knowing that (x, y ) lies on the equilibrium curve. For constant relative volatility, we can express the equilibrium curve as a simple equation using the definition of relative volatility ... 

Equation (6-53) is just the definition of the relative volatility applied to the conditions in the reboiler. Material balances for these components around the reboiler are... 

Gamma-phi form. If we substitute the low-pressxue gamma-phi expression for the K-factors (12.1.7) into the definition of the relative volatility (12.1.12), we obtain... 

As the vapor pressures p and pi strongly depend on temperature, evaluation of (5.1-3) requires a knowledge of temperature. A simpler formulation of gas-liquid equilibrium is possible by using relative volatilities a according to the following definition ... 

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