Distillation example

Esters of medium volatility are capable of removing the water formed by distillation. Examples are propyl, butyl, and amyl formates, ethyl, propyl, butyl, and amyl acetates, and the methyl and ethyl esters of propionic, butyric, and valeric acids. In some cases, ternary azeotropic mixtures of alcohol, ester, and water are formed. This group is capable of further subdivision with ethyl acetate, all of the ester is removed as a vapor mixture with alcohol and part of the water, while the balance of the water accumulates in the system. With butyl acetate, on the other hand, all of the water formed is removed overhead with part of the ester and alcohol, and the balance of the ester accumulates as a high boiler in the system. 

FIG. 13-106 Distillate -composition profile for the miilticomponent-batch-distillation example. 

TABLE 13-32 Initial and Fixed Conditions, Controller and Hydraulic Parameters, and Disturbance for Ideal Binary Dynamic-Distillation Example... 

DISTILLATION TABLE 13-33 Results for Ideal Binary Dynamic-Distillation Example of Table 13-32 ... 

FIG. 13-109a Resp onses after a 30 percent increase in the feed flow rate for the mnlticomponent-dynamic-distillation example of Fig. 13-100. Profiles of liquid mole fractions at several times. 

The component balance equations for reflux drum, column enriching section, feed plate, column stripping section and the column base and reboiler are very similar to those derived previously for the binary distillation example CONSTILL, but are now expressed in multicomponent terms as described in Section 3.3.3.4. 

As a more realistic distillation example, let us now develop a mathematical model for a multicomponent, nonideal column with NC components, nonequimolal overflow, and inefficient trays. The assumptions that we will make are ... 

A similar apparatus but of a larger size can be used for "industrial batch distillation Examples of batch stills are shown in Figs 293, 291 292, pp 384—86 of Riegel s book (Ref 1)... 

Seader and Henley (1998) provided a detailed account of the merits and demerits of different integration methods with typical conventional batch distillation examples. They have noted three particular issues with the integration methods applied in batch distillation calculations that require attention. These are the truncation error, stability and stiffness ratio. These will be briefly discussed in the following. 

Figure 2.16 Composition profiles in multicomponent distillation, Example 2,4, (a) Liquid <6,1 vapor, (Prom C. J. King , Separation Processes. 2d ed, Copyright by McGraw-Hill, hie. Reprinted by permission.)...

The optimal robust controller designed with one of the new synthesis techniques is generally not of a form that can be readily implemented. The main benefit of the new synthesis procedure is that it allows the designer to establish performance bounds that can be reached under ideal conditions. In practice, a decentralized (multiloop) control structure is preferred for ease of start-up, bumpless automatic to manual transfer, and fault tolerance in the event of actuator or sensor failures. Indeed, a practical design does not start with controller synthesis but with the selection of the variables that are to be manipulated and measured. It is well known that this choice can have more profound effects on the achievable control performance than the design of the controller itself. This was demonstrated in a distillation example [17, 18] in which a switch from reflux to distillate flow as the manipulated variable removes all robustness problems and makes the controller design trivial. 

FIG. 13-118 Solution for a simple distillation example using Mathematica, version 5.0.1. 

REACTION ZINC DUST DISTILLATION Example Anthracene from Alizarin or Quinizarin... 

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