Batch Distillation - Distill Specification
Specify the actual distillation in a batch distillation unit. Distill is the only action that advances the simulated time. Distill actions are allowed only in sequential segments of the Overall Operating Policy table on the Batch Distillation Main Window . Only one Distill action is allowed in each policy segment.
Usage
Each Distill action continues until stopped by either a Run Until Condition or a Global Stop Criterion.
In the first policy only, the Distill action requires values for the Boilup Specification and the Distillate Specification. The values specified for this first Distill action are used by all subsequent Distill policy segments until new values are supplied on another Distill Specification in a subsequent Distill policy segment.
Boilup Specification
The Top Vapor Rate is the primary setting for column loading. It directly affects boilup, stillpot heat duty and condenser duty.
Alternatively, the Use Reboiler Heat Exchanger Model can be chosen to specify the boilup specification. If using this option, configuration data for the reboiler HX model should be entered before any data is entered for the boilup specification. Any process stream from the flowsheet can be chosen as Reboiler Heating stream. The heating utility flow rate should be specified here. The actual flow rate of the selected stream is not altered, since it serves only as a reference stream to obtain the temperature, pressure and composition of the heating utility. Pressure Drop for the stream in the heat exchanger can be given. This is utilized to change the outlet temperature and conditions of the stream.
Distillate Specification
The Distillate Specification may be supplied as BULK Molar Reflux Ratio, BULK Distillate Rate, Phase Molar Reflux Ratio, or Phase Distillate Flowrates. Phase-specific data gets enabled only if Holdups are also phase specific (refer to the Batch Distillation - Liquid Holdup window). When phase specific data is given, data for both L1 and L2 phases is required. This specification may be varied by a dynamic controller in order to meet a temperature or purity specification.
Use Condenser Heat Exchanger Model may be chosen as an additional specification.
This allows simulating the condenser with a user-configurable heat exchanger model. If using this option, configuration data should be entered in the Condenser HX window before entering data for the distillate specification. Any process stream from the flowsheet can be chosen as coolant stream. The cooling utility flow rate should be specified here. The actual flow rate of the selected stream is not altered, since it serves only as a reference stream to obtain the temperature, pressure and composition of the cooling utility. Pressure Drop for the stream in the heat exchanger can be given and this is utilized to change the outlet temperature and conditions of the stream.
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 - Distill Specification window is accessed by selecting Distill 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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