Advanced Distillation Technologies

Design, Control and Applications

Anton A. Kiss

• Publisher: Wiley
• Year: 2013
• Print ISBN: 9781119993612
• eBook ISBN: 9781118544815
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Industrial & Technical Chemistry

Distillation has historically been the main method for separating mixtures in the chemical process industry. However, despite the flexibility and widespread use of distillation processes, they still remain extremely energy inefficient. Increased optimization and novel distillation concepts can deliver substantial benefits, not just in terms of significantly lower energy use, but also in reducing capital investment and improving eco-efficiency. While likely to remain the separation technology of choice for the next few decades, there is no doubt that distillation technologies need to make radical changes in order to meet the demands of the energy-conscious society.

Advanced Distillation Technologies: Design, Control and Applications gives a deep and broad insight into integrated separations using non-conventional arrangements, including both current and upcoming process intensification technologies.

It includes:

• Key concepts in distillation technology
• Principles of design, control, sizing and economics of distillation
• Dividing-wall column (DWC) – design, configurations, optimal operation and energy efficient and advanced control
• DWC applications in ternary separations, azeotropic, extractive and reactive distillation
• Heat integrated distillation column (HIDiC) – design, equipment and configurations
• Heat-pump assisted applications (MVR, TVR, AHP, CHRP, TAHP and others)
• Cyclic distillation technology – concepts, modeling approach, design and control issues
• Reactive distillation – fundamentals, equipment, applications, feasibility scheme
• Results of rigorous simulations in Mathworks Matlab & Simulink, Aspen Plus, Dynamics and Custom Modeler

Containing abundant examples and industrial case studies, this is a unique resource that tackles the most advanced distillation technologies – all the way from the conceptual design to practical implementation.

The author of Advanced Distillation Technologies, Dr. Ir. Anton A. Kiss, has been awarded the Hoogewerff Jongerenprijs 2013. Find out more (website in Dutch)...

1

Basic Concepts in Distillation

1.1 Introduction

Distillation is a thermal separation method for separating mixtures of two or more substances into its component fractions of desired purity, based on differences in volatilities of components—which are in fact related to the boiling points of these components—by the application and removal of heat. Note that the term distillation refers to a physical separation process or a unit operation. Remarkably, distillation can be combined with another distillation operation, leading to a dividing-wall column (Harmsen, 2010), or with a chemical reaction, leading to reactive distillation (Sundmacher and Kienle, 2003; Sundmacher, Kienle, and Seidel-Morgenstern, 2005; Luyben and Yu, 2008; Sharma and Singh, 2010), and/or other chemical process operations (Schmidt-Traub and Gorak, 2006).

At the commercial scale, distillation has many applications, such as the separation of crude oil into fractions (e.g., gasoline, diesel, kerosene, etc.), water purification and desalination, the splitting of air into its components (e.g., oxygen, nitrogen, and argon), and the distillation of fermented solutions or the production of distilled beverages with high alcohol content (Forbes, 1970). Distillation underwent enormous development due to the petrochemical industry, and as such it is one of the most important technologies in the global energy supply system (Harmsen, 2010). Essentially, all transportation fuel goes through at least one distillation column on its way from crude oil to readily usable fuel, with tens of thousands of distillation columns in operation worldwide. In view of the foreseen depletion of fossil fuels and the switch to renewable sources of energy such as biomass, the most likely transportation fuel will be ethanol, methanol, or derivatives. The synthesis of alternative fuels leads typically to aqueous mixtures that require distillation to separate ethanol or methanol from water. Consequently, distillation remains the separation method of choice in the chemical process industry. The importance of distillation is unquestionable in providing most of the products required by our modern society (e.g., transportation fuel, heat, food, shelter, clothing, etc.).

The analysis, design, operation, control, and optimization of distillation columns were studied extensively in the last century but, until the introduction of computers, only hand calculations and graphical methods were developed and applied in distillation studies. As distillation analysis involves many iterative vapor–liquid phase equilibrium calculations, and tray-to-tray component balances that are ideal for digital computation, the use of computers has had a beneficial effect in recent decades (Luyben, 2011). Many companies still have their own in-house process simulators, although commercial steady-state and dynamic process simulators (e.g., Aspen Plus^®, Aspen Dynamics^®, ChemCAD, Aspen HYSYS^®, PRO/II, etc.) are now available and dominate the field—with distillation playing a key role in these simulators.

The topic of distillation is very broad and it would require many volumes to cover it in a comprehensive manner. Consequently, for more details the reader is directed to several good books, which cover this subject in great detail: Kister (1992a), Kister (1992b), Taylor and Krishna (1993), Stichlmair and Fair (1998), Seader and Henley (1998), Doherty and Malone (2001), Mujtaba (2004), Petlyuk (2004), Lei, Chen, and Ding (2005), and more recently Luyben (2006, 2011).

It is important to note that distillation can separate chemical components only if the compositions of the vapor and liquid phases that are in equilibrium with each other are different. Therefore, a practical understanding of vapor–liquid equilibrium (VLE) is essential for the analysis, design, and control of distillation columns. This introductory chapter presents in a structured and convenient way the basic concepts of distillation: property methods, vapor pressure, bubble point, relative volatility, VLE, vapor–liquid–liquid equilibrium (VLLE), ternary diagrams, residue curve maps (RCM), and theoretical stage and short-cut design methods for distillation.

1.2 Physical Property Methods

An extremely important issue in distillation calculations is the selection of an appropriate physical property method that will accurately describe the phase equilibrium of the chemical system. Missing or inadequate physical properties can undermine the accuracy of a model or even prevent one from performing the simulation. For this reason, finding good values for inadequate or missing physical property parameters is crucial to a successful simulation. Nevertheless, this depends strongly upon choosing the right estimation methods—an issue already recognized in the world of chemical processes modeling by the axiom “garbage in, garbage out” which means that the simulation results have the same quality as the input data/parameters (Carlson, 1996). In most design situations there is some type of data—for example, VLE reported in the literature, experimental measurements, and data books (Gmehling et al., 1993; Perry and Green, 1997)—that can be used to select the most appropriate physical p...

Table of contents

• Cover
• Title Page
• Copyright
• Dedication
• Preface
• Acknowledgements
• Chapter 1: Basic Concepts in Distillation
• Chapter 2: Design, Control and Economics of Distillation
• Chapter 3: Dividing-Wall Column
• Chapter 4: Optimal Operation and Control of DWC
• Chapter 5: Advanced Control Strategies for DWC
• Chapter 6: Applications of Dividing-Wall Columns
• Chapter 7: Heat Pump Assisted Distillation
• Chapter 8: Heat-Integrated Distillation Column
• Chapter 9: Cyclic Distillation
• Chapter 10: Reactive Distillation
• Index