Phase Envelopes

About Phase Envelopes

Phase Envelopes generate vapor-liquid equilibrium (VLE) data for specified compositions of a Fluid Type. They help you visualize, analyze, and validate the vapor-liquid equilibrium (VLE) behavior of your fluids.

Concepts

• Unlike Trends and Profiles, Phase Envelopes appear only on the Canvas, not in the Simulation Manager.

• Currently, Phase Envelopes support only Compositional Fluid Types that use an equation of state (EOS) as their System method and Vapor/Liquid (VLE) as their Phases selection.

• Phase Envelopes can reference a specified fluid (Fluid Type configuration) or a specified stream (Stream configuration).

• For Fluid Type configuration, when you add a Fluid Type to a Phase Envelope, the software sets the composition values for the Phase Envelope to those of the Fluid Type.

• For Stream configuration, when you specify the stream to use, the software loads the composition values and Fluid Type from the stream data and you cannot change these values in the Phase Envelope.

• If you switch the Phase Envelope from Stream configuration to Fluid Type configuration, the Phase Envelope retains the Fluid Type selection, composition, temperature, and pressure from the stream.

• Phase Envelopes display bubble point and dew point curves at temperature and pressure for a vapor-liquid equilibrium (VLE) mixture. They also include the following critical data:

  • Critical point

  • Cricondenbar point

  • Cricondentherm point

• For Stream configuration, the Phase Envelope also displays the operating point (temperature and pressure) of the stream.

• The software normalizes the compositions for the Phase Envelope when it calculates the phase data.

• Phase Envelopes work best on a dry basis.

• Phase Envelopes work best with nonpolar components; if you include polar components (such as H2O, MeOH, or TEG) in the fluid composition, a warning message appears in the Log pane to indicate the poor behavior.

• Phase Envelope messages appear in the Thermo Diagrams report in the Log pane.

• If the graph does not display any data after adding a Fluid Type or process stream to the Phase Envelope, you can review the messages in the Thermo Diagrams report in the Log pane to troubleshoot the issue.

Actions

• Create a Phase Envelope on the Canvas.

• Select a Fluid Type for the Phase Envelope; alternatively, drag a Fluid Type onto the Phase Envelope on the Canvas.

• Select whether the Phase Envelope displays data in terms of molar compositions (molar basis) or mass compositions (mass basis).

• Change the position of the legend on the graph.

• Set the composition for each component in the Fluid Type.

• Generate a Microsoft Excel report for the phase data.