Info

note: To convert (lb-mol)/h to (kg-mol)/h, multiply by 0.454.

note: To convert (lb-mol)/h to (kg-mol)/h, multiply by 0.454.

Distillation Simulator
FIG. 13-94 Configuration and conditions for the simulation of the atmospheric tower of crude unit.
Distillation Curve Example
FIG. 13-95 Comparison of computed stage temperatures with plant data for the example of Fig. 13-94.

agreement with computed values in Fig. 13-95. Computed sidestream-product TBP distillation curves are in reasonably good agreement with values converted from plant ASTM distillations as shown in Fig. 13-96. Exceptions are the initial points of all four cuts and the higher-boiling end of the heavy-distillate curve. This would seem to indicate that more theoretical stripping stages should be added and that either the percent vaporization of the tower feed in the simulation is too high or the internal-reflux rate at the lower draw-off tray is too low. The liquid-rate profile in the tower is shown in Fig. 13-97. The use of two or three pump-around circuits instead of one would result in a better traffic pattern than that shown.

Batching Plant Components Drawing
FIG. 13-96 Comparison of computed TBP curves with plant data for the example of Fig. 13-94.
Distillation Pump Around

FIG. 13-97 Liquid-rate profile for the example of Fig. 13-94.

100,000 200,000 300,000

Liquid flow rate leaving stage, Ib/h

FIG. 13-97 Liquid-rate profile for the example of Fig. 13-94.

Batch distillation, which is the process of separating a specific quantity (the charge) of a liquid mixture into products, is used extensively in the laboratory and in small production units that may have to serve for many mixtures. When there are N components in the feed, one batch column will suffice where N - 1 simple continuous-distillation columns would be required.

Many larger installations also feature a batch still. Material to be separated may be high in solids content, or it might contain tars or resins that would plug or foul a continuous unit. Use of a batch unit can keep solids separated and permit convenient removal at the termination of the process.

Was this article helpful?

0 0
Making Your Own Wine

Making Your Own Wine

At one time or another you must have sent away for something. A

Get My Free Ebook


Post a comment