الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
A linearized model of a two stage, desa1ting, distillation column was developed and ana1yzed with respect to its dynamic behavior when subjected to various upsets. In addition to the two flash stages, the model contains realistic representations of associated auxiliary equipment such as a preheater, a circulation pump, and a brine heater. The system investigated therefore contains a sufficient number of COmponents to provide insight to the stage-stage and the stage-component interaction characteristics of large scale plants. This is the first known model containing sufficient complexity to reveal such interaction characteristicIn general, the system was shown to be stable to small pertur¬bations. The time response curves of the model indicate that the quantities of brine in each of the two stages are the most sensitive variables with respect to the question of achieving satisfactory system performance. The transients normally can be represented in two parts. The first is a relative short period of about ten mean residence times during which the most rapid change takes place. This period is followed by a long duration slow drift. Periodic oscilla¬tions were not encountered for realistic values of the system parameters. However, the undesirable operating conditions of blow¬down or flooding can be produced by all classes of upsets investigated, as brine is either accumulated in the system as a whole or transferred from one stage to the other. A sensitivity analYsis shows that proper choice of certain
design parameters, such as the non-dimensional heat transfer para¬meters Of the heaters, or the slope of the pump curve, can delay the occurrence of blowthrough or floOding, but these characteristics Can¬not be prevented by SUitable parameter selection alone.
A simple Control problem was Considered in which it was shown
that undeSirable operation cannot neceSSarily be avoided following an energy uPSet in the system by energy compenSation alone. However, Satisfactory performance can be achieved by two parameter Controls; that is, Control over both the steam temperature and the feed flow rate.