Batch Distillation - Draw Specification
Define draw streams from the batch distillation unit during its operation. Draws may be taken from any stage in the unit. Multiple draws are allowed in any policy segment.
Usage
The simulated time advances through a series of Distill actions. The durations of policy segments with Distill actions always is controlled by Run Until Conditions and Global Stop Criteria. A continuous draw that includes its own stopping criterion (e.g., amount at a rate, amount or rate over a time period) cannot appear in the same policy segment as a Distill action. These draws may appear in a parallel (concurrent) non-sequential segment.
Draw Stream
Select the product stream to use for this draw from the list of product streams attached to the unit on the Process Flow Diagram. Each product stream may be used for only one Draw or Cut product.
Draw Mode
Instantaneous draws may be taken from the stillpot or accumulator. Continuous draws may be removed from any stage in the column, including the stillpot and condenser, but not from the accumulator.
You may select the draw mode as:
Instantaneous amount: The specified amount is removed instantaneously from the stillpot or accumulator. Instantaneous draws are removed before any Distill action in the same policy segment.
At a rate: The draw continues at the specified rate until the end of the policy segment.
Amount at a rate: The draw continues at the specified rate until the specified amount has been removed. This is available only for non-sequential segments.
Amount over a time period: The draw is removed at a rate that removes the specified amount of product in the stipulated time period. This is available only for non-sequential segments.
Rate over a time period: The draw is removed at the specified rate for the stipulated time period. This is available only for non-sequential segments.
Amount/Rate/Time Period
The required data depends on the Draw Mode. The data fields corresponding to the selected option are required entries (i.e., there are no defaults).
Draw Location
Specify the location of the draw. An instantaneous draw may only be removed from the accumulator or the stillpot. Continuous draws may be from any stage (except the accumulator), including stillpot and reflux splitter.
To change the dimensional units displayed for entries, press the UOM button to view and use the Unit of Measure Selection Window.
How to get to this window
The Batch Distillation - Draw Specification window is accessed by selecting Draw 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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