The document discusses the transfer basis tab in sub-flowsheets. The transfer basis determines how properties are passed between sub-flowsheets and parent flowsheets when they use different property methods. It can pass pressure and temperature, vapor fraction and temperature, or other combinations to provide a consistent interface. The transfer basis also helps control vapor fraction, temperature, or pressure calculations for streams at column sub-flowsheet boundaries.

1. 2-8 Sub-Flowsheet Property View
2-8
2.2.3 Transfer Basis Tab
The transfer basis for each Feed and Product Stream is listed on the
Transfer Basis tab. The transfer basis only becomes significant when the
sub-flowsheet and Parent flowsheet’s fluid packages consist of different
property methods. The transfer basis is used to provide a consistent
means of switching between the different basis of the various property
methods.
Transfer Basis Description
T-P Flash The Pressure and Temperature of the Material stream are passed
between flowsheets. A new Vapour Fraction is calculated.
VF-T Flash The Vapour Fraction and Temperature of the Material stream are
passed between flowsheets. A new Pressure is calculated.
VF-P Flash The Vapour Fraction and Pressure of the Material stream are
passed between flowsheets. A new Temperature is calculated.
P-H Flash The Pressure and Enthalpy of the Material stream are passed
between flowsheets.
User Specs You define the properties passed between flowsheets for a Material
stream.
None Required No calculation is required for an Energy stream. The heat flow is
simply passed between flowsheets.
Figure 2.5
The Transfer Basis is also
useful in controlling VF, T or P
calculations in column sub-flowsheet
boundary streams
with close boiling or nearly
pure compositions.