Application of a new parallel column model to simulating maldistribution in packed columns

Abstract

Parallel column models were first proposed in the 1950s for investigating the sensitivity of the HETP in a packed column to maldistribution. Although it is possible to develop a parallel column model using a process simulator, it may take considerable effort to arrange and specify the columns.Recently, we have described what we call a Parallel Column Model (PCM) with the aim of making it easier to model Dividing Wall Columns (DWCs), we realized that it should also be possible to use the PCM to model maldistribution in packed columns. Both equilibrium stage and rate-based column models can easily be used within this framework.In this paper we review the literature on simulating packed columns with maldistribution. We also show how easily our PCM may be used to describe maldistribution in packed columns and show how our results match the obtained results of earlier papers. We propose a simple bed effectiveness approximation that can use the results from a regular column simulation and assign stages to specific packed beds such that the resulting column suffers less from liquid maldistribution. We illustrate the use of this approximation with two practical examples involving the design of commercial scale columns.