Analysing divided wall columns

Abstract

In chemical processes, beside main products, significant quantities of by-products are often produced due to thermodynamics. Therefore, separation techniques and methods play such an important role, in chemical technologies, as reactor systems. Rectification is one of the most frequently used fluid separation process, which usually involves significant energy consumption. The production of hot and cold energy causes notable environmental load (CO2 emission, dust pollution, etc.). Hence, from environmental point of view, research on energy saving in separation processes, for instance analysing divided wall columns (DWC), is exceedingly important. This article focuses on how to find more efficient structures with minimal energy consumption. The DWC system is a promising energy-saving alternative for separating multi-component mixtures (Chem Eng Process 38: 549–562, 1999; Chem Eng Process 49: 825–835, 2010). The innovation of this equipment is a wall which divides the inner space of the tower separating the feed and the side stream-product zones. The side stream and the feed stream are prevented from mixing by this wall. The DWC possesses greater efficiency than common column sequences. Conventional columns with side stream can be converted to DWC. In this article, several constructions of DWC are investigated with simulation experiments. The structure of the column is implemented in Aspen Plus in: 2006 Reference Guide, AspenTech Inc., Cambridge, 2006 simulator using the Radfrac unit of the software. The effects of the split ratio, the height and the vertical position of the wall, as the main parameters of DWC, are analysed.