Graphical design and analysis of thermally coupled sidestream columns using column profile maps and temperature collocation

Abstract

A systematical procedure is presented to design thermally coupled sidestream units like side rectifiers and side strippers are presented in this article. The method combines the column profile map technique to assess topological characteristics of the specific configuration with temperature collocation to rigorously ensure a realizable column design, without making assumptions with regard to the phase equilibrium or product specifications. The proposed methodology offers a unique graphical insight into the challenging problem of thermally coupled column synthesis. Techniques are presented for highlighting superior designs or eliminating inferior ones, based on vapor flow rate, number of stages, and thermodynamic efficiency. Design parameters such as the feed and side-draw trays that may require insight or experience are products of the procedure. Design solutions obtained using this methodology can be used to initialize the state of the art process flow sheeting tool, AspenPlus™, which typically leads to fast convergence to the desired product purities without further adjustments. © 2010 American Institute of Chemical Engineers AIChE J, 2011