Batch Distillation - Control Specification
Specify a dynamic controller by defining a temperature or purity specification on any stage. This specification will be satisfied by varying the reflux ratio. Only one dynamic controller is allowed in any policy segment.
Usage
Controlled Variable
Select the type of specification required as either Temperature, Temperature Increment or Purity. The Purity may be molar or weight fraction.
Stage Selection
Push this button to display the Batch Distillation - Stage Selection window, and select the stage(s) for the controlled variable. For a Temperature or Purity specification, the number of the specification stage must be entered. For the Temperature Increment specification, you must enter the numbers of the two stages for the temperature increment.
Component Selection
Push this button to display the Batch Distillation - Component Selection window. Then, select the first and last component in the range of the Purity specification.
Manipulated Variable
The Distillate Specification of the current Distill action is varied to meet the specification for the Controlled Variable. Select a Manipulated Variable from either Molar Reflux Ratio or Distillate Rate; then enter the limiting minimum and maximum values.
Minimum/Maximum Values
These define the range over which the Manipulated Variable may be changed. Entries are required (there are no defaults).
Dynamic Controller Gain
The controller gain represents a proportional controller action. The default controller gain is 1.0, which represents a 1:1 control ratio (i.e., no scaling).
To change dimensional units displayed for entries shown on the screen, open the Unit of Measure Selection Window by pressing the UOM button.
How to get to this window
The Batch Distillation - Control Specification window is accessed by selecting Control in the Action/Condition table in the Batch Distillation - Policy Segment window and then clicking on the linked text under Description.
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