BATCHFRAC Policy Segment

Use this window to specify the elements of a policy segment. At least one policy segment action is required in each policy segment.

Usage

Overriding conditions for policy segment

Other policy segment can overwrite any of the following Specifications:

Pressure profile, Condenser, Heater/Cooler, Thermodynamics, Liquid holdups and Reactions.

Typically, Specifications provided in the BATCHFRAC main window will be used for the first policy. For other policies, User can overwrite the specification by visiting the corresponding specification DEW at policy level; else the previous policy specification will be used for calculations.

Holdup specifications will not be overwritten for Standard type policy.

Reactions are not supported for Total Reflux type policy.

Action/Condition

Select the desired Action/Condition from the drop down list; then click on the text under Description to open the appropriate definition window. The selections available are:

Charge

Specify Charges for the unit. Charges may be instantaneous or continuous, and may apply to any stage of the column. Only the still pot allows Instantaneous charges. Instantaneous charge can also be supplied by giving Rate and Time. Continuous charges may be made to any stage except the condenser. Initial charge to still pot is required in the first policy.

Draw

Specify Draws for the unit. This action is not valid for a total reflux policy. Draws may be taken from any stage to any accumulator by specifying the phase and the rate. Note that dumping the contents of the accumulator is a Dump rather than a draw.

Distill

Specify the Distill actions for the unit. This indicates when distillation is actually taking place. Only one Distill action is allowed in a policy segment.

Control

Specify a dynamic controller which varies the reflux ratio to meet a temperature or purity specification. Only one dynamic controller is allowed in a policy segment. This action is not valid for a total reflux policy.

Run Until

Specify Run Until Conditions, which define conditions for ending the policy segment. The segment terminates when any of the conditions is satisfied. This action is not valid for a total reflux policy.

Dump

Dumps the contents of the accumulator into a defined product stream at the beginning of the policy segment. This action is not valid for the first policy as there will not be any contents in the accumulators.

Recycle

Specify Recycle conditions which will define the fraction recycle of each phase to other stages. This action is not valid for the first policy.

Decant

Decant action card is valid for VLLE thermo only. This action is not valid for a total reflux policy.

How to get to this window

The BATCHFRAC- Policy Segment window is accessed by pressing the Enter Data button in the Overall Operating Policy table on the BATCHFRAC Main Window. You should ensure to select the correct policy type before accessing this window.

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