Daniel Beneke

Column profile maps as a tool for synthesizing complex column configurations

Abstract There has recently been a renewed interest in the design of distillation processes due to rising energy cost and growing environmental concerns. Column profile maps (CPMs) have been developed as a graphical tool to simplify the design procedure of distillation schemes as well as a method for analyzing existing processes. Using CPMs one is able to change topology within the composition space to suit the requirements of the separation and hence many separations that have been thought of as difficult or unviable can now be better understood and consequently new designs may be devised. The CPM technique has also been proven to be extremely useful as a design tool for complex columns, as configurations irrespective of complexity can be modeled and graphically understood. This paper aims to summarize the most important and interesting results and applications obtained using the CPM technique. It shows how CPMs may be used to synthesize complex columns like a Petlyuk or Kaibel column, as well as showing how new sharp split separations can be devised.

Understanding distillation using column profile maps

Understanding Distillation Using Column Profile Maps enables readers to understand, analyze, and design distillation structures to solve common distillation problems, including distillation by simple columns, side rectifiers and strippers, multiple feed columns, and fully thermally coupled columns. In addition, the book presents advanced topics such as reactive distillation, membrane permeation, and validation of thermodynamic models. For all these processes, the authors set forth easy-to-follow design techniques, solution strategies, and insights gained using CPMs.

Pinch Point Calculations and Its Implications on Robust Distillation Design

Abstract Rising energy costs and growing environmental awareness motivate a critical revision of the design of distillation units. Systematic design techniques, such as the rectification body, column profile map, and temperature collocation methods, require exact knowledge of all pinch points in a particular system, because these stationary points delineate the possible composition trajectories realizable in separation columns. This paper demonstrates novel methods for rigorously determining all pinch points for the constant relative volatility, ideal and non-ideal systems. Constant relative volatility and ideal solution systems are transformed into one-dimensional polynomial and nonlinear functions, regardless of the number of the components. A deflation method is proposed to locate all zeros in ideal and non-ideal zeotropic problems. For more challenging non-ideal problems, a novel hybrid sequential niche algorithm is used to solve hard azeotropic problems successfully. Finally, the design implications of these pinch point locations are investigated to show how new separation configurations can be devised. Methodically the paper points out the use of rigorous pinch point computations in conjunction with continuous composition profiles for robust distillation design.

Robust Thermodynamically-guided Algorithms for Synthesis of Energy Efficient Separation Networks

Abstract Distillation has a particularly high potential for energy savings, as it accounts for around 40–70% of capital and operating costs in petrochemical and commodity industries. However, numerous existing techniques that have been proposed to facilitate the design often lack the robustness and reliability needed to rigorously solve the problem, largely due to simplifying assumptions. In this contribution, we present computational methods which exploit a novel thermodynamically motivated problem transformation, entitled temperature collocation, rather than using classical tray-by-tray models which fail in pinched regions. This novel methodology applies to ideal, non-ideal and azeotropic mixtures, and is independent of the number of components. Due to the generalised nature of the method, we have also addressed the synthesis of complex column configurations as well as heat integration of distillation trains. Furthermore, the robust synthesis algorithm is presented, a method that automatically synthesizes a distillation network for given product purity requirements. Entire separation flowsheets are generated with rigorous thermodynamic models without the need to introduce limiting simplifications as is the case with existing shortcut techniques. The computational approach guarantees to identify realizable columns with a finite number of trays and operating conditions, which may easily be validated with industrial flowsheet simulator software packages like Aspen Plus.