HETEROGENEOUS BINARY AZEOTROPES

Fig. 17. Column sequence for separating a binary heterogeneous azeotropic mixture, and B, where represents the process feed mole fraction, (a)...

As seen in Table 1, the boiling temperature of the possible entrainers is either lower or higher than that of the original components. All candidates form a binary heterogeneous azeotrope with -hexane. Methanol and acetonitrile... 

For the synthesis of heterogeneous batch distillation the liquid-liquid envelope at the decanter temperature is considered in addition to the residue curve map. Therefore, the binary interaction parameters used in predicting liquid-liquid equilibrium are estimated from binary heterogeneous azeotrope or liquid-liquid equilibrium data [8,10], Table 3 shows the calculated purity of original components in each phase split at 25 °C for all heterogeneous azeotropes reported in Table 1. The thermodynamic models and binary coefficients used in the calculation of the liquid-liquid-vapour equilibrium, liquid-liquid equilibrium at 25 °C and the separatrices are reported in Table 2. 

There are many binary heterogeneous azeotropes which are not listed in the literature because the azeotropic data can readily be calculated from the vapor pressure data of the components. 

Give minimum boiler ternary heterogeneous azeotrope with alcohol and water, or most preferably binary heterogeneous azeotrope with water. The entrainer must form also a minimum binary azeotrope with the alcohol. 

At atmospheric pressure, the n-butanol-water system exhibits a minimum boiling azeotrope and partial miscibility, and hence a binary heterogeneous azeotrope. Figure 1.8 shows the Tyx and Pyx phase diagrams for l-propanol(l)-water(2) azeotropic mixture obtained from the Aspen Plus simulator using the NRTL activity coefficient model. 

The simplest case of combining VLE and LEE is the separation of a binary heterogeneous azeotropic mixture. One example is the dehydration of 1-butanol, a self-entraining system, in which butanol (117.7°C) and water form a minimum-boiling heterogeneous azeotrope (93.0°C). As shown in Eig. 13-69, the fresh feed maybe added... 

Figure 8-4. Binary heterogeneous azeotrope (A) two-column distillation system, (B) McCabe-Thiele diagram for column 1. (C) McCabe-Thiele diagram for column 2 with expanded coordinates.

Solve binary heterogeneous azeotrope problems, including the drying of organic solvents, using McCabe-Thiele diagrams... 

Cl. Derive Eq. (8zZ) for the two-column, binary, heterogeneous azeotrope system. 

C3. For a binary heterogeneous azeotrope separation, the feed can be introduced into the liquid-liquid... 

The separation of a binary heterogeneous azeotrope is often much easier than the separation of a binary homogeneous azeotrope because the liquid-liquid phase equilibrium in a decanter can be used to facilitate the separation. No third component has to be introduced, which avoids many problems of trace amounts of the added component in the product streams. 

We use the w-butanol-water system in this chapter as an example of this type of binary heterogeneous azeotropic system. A straight-forward two-column distillation system can be used to easily achieve high-purity products. A simple control structure is developed that is capable of handling very large disturbances in throughput and feed composition. The control... 

A simple control stmcture has been developed and demonstrated to be remarkably robust for the separation of the binary heterogeneous azeotropic w-butanol-water system. The process configuration consists of two stripping columns, a decanter, and a single condenser. A tray temperature is controlled in each column. Very large disturbances in feed flowrate and feed composition are effectively handled with product compositions maintamed close to the desired values. 

If the azeotrope is a binary, heterogeneous azeotrope, that means there is a region where the two... 

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