Boiling Point Elevation

From SysCAD Documentation

Navigation: User Guide -> Boiling Point Elevation

Overview

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 in a Project - The BPE method can be set to a default throughout a project by selecting the required method on the Species page in Plant Model (View - Plant Model - Species Tab).

• 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.

• BPE in Units and Pipes - This describes the information shown in the access window of pipes, tanks, etc.