Boiling Point Elevation

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Navigation: User Guide ➔ Stream Properties ➔ Boiling Point Elevation

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Solubility Boiling Point Elevation pH Charge Steam and Water Sulfuric Acid

Latest SysCAD Version: 25 February 2021 - SysCAD 9.3 Build 138.28098

Related Links: Boiling Point Elevation Discussion


The Boiling Point Elevation, BPE, of a liquid solution at the stream pressure is the difference between the temperature at which the liquor will boil and the temperature at which water would boil at the same pressure. The magnitude of the BPE is proportional to the number of solute particles in the liquor - i.e. this is a Colligative property.

SysCAD allows a number of different methods of calculating BPE:

  • None - the boiling point of a liquor stream will be equal to the boiling point of saturated water;
  • van't Hoff - this uses the van't Hoff constants and the molality of the ionic species to calculate the BPE. This is described in Boiling Point Elevation.
  • Bayer Species Model - The implementation of a generic Bayer species model in SysCAD using the Boiling Point Elevation Calculations shown.
  • Client Species Models - clients may use their own specific BPE equations in their implemented Species Models.

Boiling Point Elevation Discussion contains further information regarding this topic.

Implementation in SysCAD

  • Entering BPE Data in the Species Properties Database - A description of the van't Hoff constants that can be entered in the Species Properties Database. These will be used with the Standard Species Model. This also describes the methodology used to calculate the BPE using the van't Hoff constants.
  • Choosing the Default BPE Method to be active in a Project - On the Species page in Plant Model (View - Plant Model - Species Tab) the user may make the following adjustments to the BPE method used throughout a project by the Standard Species Model:
    1. Set the default BPE method;
    2. Disable the BPE functionality;
    3. Set the BPE lower and upper limits.
  • Choosing BPE Method in a single Unit with VLE - The BPE method can be changed in any Individual unit with VLE enabled by selecting the required method on the VLE page. This will override the project default method in the selected unit. In addition, the user may scale the calculated BPE value, and add an offset, if required.
  • BPE in Units and Pipes - This describes the information shown in the access window of pipes, tanks, etc.