Default Units of Measure for Problem Data Input
(Input \ Units of Measure menu)
This window is used to modify the Units of Measure (UOM) selected for input data in the current problem.
Initially, the parameters in this window have default units according to the pre-defined set selected for input data in the Default Sets of Units of Measure Window. You have the option to select a new UOM set for the current problem, or change some of the existing units, standard vapor conditions, and the TVP and RVP basis.
To create a new UOM set or to modify an existing set, refer to the Units of Measure Library Window.
Usage
Select the Input \ Units of Measure command to display this window. The Basis field displays the UOM set that has been selected for data input.
Initialize from UOM Library button
To select a different UOM set to be used in the current problem, push this button to display the "Initialize Units of Measure from UOM Library" window, where you can select a new set from the pre-defined sets in the UOM Library. Choose a set which closely matches the input units for the current problem, so that you will have only a few units to modify.
Default Units of Measure for Problem Data Input
Displays most of the parameters whose data can be entered at input time and their selected units. You can change these units as necessary by selecting the desired unit from the drop-down list boxes. Note that these changes are applied only for the current problem and does not change the contents of the selected UOM set in the library. PRO/II combines some of the simple units specified here to form units for parameters which are not listed. For example, the unit for velocity is obtained by combining the units selected for length and time.
The current atmospheric pressure is shown in the Pressure Gauge Basis field which can be changed if desired.
Standard Conditions button
The standard vapor condition defaults to the value selected for the input UOM set. If you want to override this default, push this button to display the Standard Conditions Window where the desired condition can be specified. PRO/II defaults the standard vapor condition to be 22.414 cubic meters per kilogram-mole at 0.0 C, 1.0 atmosphere in Metric and SI units, or its equivalent.
Note: Standard conditions for liquid properties are different from standard vapor conditions. Users should be aware that standard conditions for liquid molar volume are different from standard conditions for a vapor or gas. Refer to Standard Conditions for a summary of the different standard conditions.
TVP and RVP Conditions button
The TVP and RVP conditions default to the selections in the input UOM set. If you want to override this default, push this button to display the TVP/RVP Conditions Window where the desired condition and method can be specified. PRO/II defaults the True Vapor Pressure temperature basis to 100 F, and the Reid Vapor Pressure calculation method to API-Naphtha.
Default Flow Rate Basis for Problem Data Input
To select default flowrate/composition basis for the flowsheet. The selected basis is applied for the newly added (or for which input data is not given) streams and unit operations. If rate basis is specified different from the default basis for the rate or composition individually, the local option will override this “Default Flow Rate Basis for Problem Data Input“option.
Additional Information
In all the data entry windows, PRO/II defaults the dimensional units in various fields to the units selected in this window. However, if for a individual field the data value is available in a different unit, you can change the dimensional unit for that field by pushing the UOM button on the Toolbar. This displays the Unit Of Measure Selection Window where you can select the required units.
Denote Energy in 10^6 Units check box
To select whether to consider duty and enthalpy UOM with/without 10^6 prefix in the flowsheet. By default this option is ON .
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