Thermosiphon Reboiler Specification

One specification must be provided to define the thermosiphon reboiler operation. The choices are explained below.

By default, Return Vapor is selected and the default value of weight fraction, 0.25 is displayed.

Return Liquid

The fraction of the reboiler circulation which returns to the column as liquid. The default unit of measure is mole fraction with a value of 0.5. The dimensional unit may be changed to mass fraction by using the Unit-Of-Measure Selection Window which is displayed when the UOM button is pushed.

Temperature

The reboiler exit temperature for the circulating fluid.

Temperature Change

The reboiler exit temperature minus the temperature at the reboiler sump.

Circulation Rate

The rate of circulation through the reboiler. Default units are moles/time.

Note that the temperature, temperature change, and circulation rate dimensional units may be changed from the default bases by using the Unit-Of-Measure Selection Window which is displayed when the UOM button is pushed.

Alternatively, instead of entering a numeric value for one of the above parameters, the value may be referenced using the Define system relative to any available unit operation or stream parameter calculated elsewhere in the simulation. See Column Parameters Available for Cross-Referencing for more details.

To run the HTRI thermosiphon reboiler that is attached to column in simulation mode, select the Rate radio button and enter the circulation rate.

Maximum Duty Adjustment

Enter the value for Maximum Duty Adjustment when “Iterative calculations with HTRI ON” option is selected for the HTRI thermosiphon reboiler. The default value is 20%. When duty is calculated by HTRI and returned to PRO/II, the Maximum Duty Adjustment limits the amount of duty change that can be accepted by the column. This duty adjustment will improve convergence by limiting the perturbation to a converged column.

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