Vapor-Liquid Equilibria Using Unifac


Book Description

Vapor-Liquid Equilibria Using UNIFAC: A Group-Contribution Method focuses on the UNIFAC group-contribution method used in predicting quantitative information on the phase equilibria during separation by estimating activity coefficients. Drawing on tested vapor-liquid equilibrium data on which UNIFAC is based, it demonstrates through examples how the method may be used in practical engineering design calculations. Divided into nine chapters, this volume begins with a discussion of vapor and liquid phase nonidealities and how they are calculated in terms of fugacity and activity coefficients, respectively. It then introduces the reader to the UNIFAC method and how it works, the procedure used in establishing the parameters needed for the model, prediction of binary and multicomponent vapor-liquid equilibria for a large number of systems, the potential of UNIFAC for predicting liquid-liquid equilibria, and how UNIFAC can be used to solve practical distillation design problems. This book will benefit process design engineers who want to reliably predict phase equilibria for designing distillation columns and other separation processes.




Thermodynamics of Solutions


Book Description

This book consists of a number of papers regarding the thermodynamics and structure of multicomponent systems that we have published during the last decade. Even though they involve different topics and different systems, they have something in common which can be considered as the “signature” of the present book. First, these papers are concerned with “difficult” or very nonideal systems, i. e. systems with very strong interactions (e. g. , hyd- gen bonding) between components or systems with large differences in the partial molar v- umes of the components (e. g. , the aqueous solutions of proteins), or systems that are far from “normal” conditions (e. g. , critical or near-critical mixtures). Second, the conventional th- modynamic methods are not sufficient for the accurate treatment of these mixtures. Last but not least, these systems are of interest for the pharmaceutical, biomedical, and related ind- tries. In order to meet the thermodynamic challenges involved in these complex mixtures, we employed a variety of traditional methods but also new methods, such as the fluctuation t- ory of Kirkwood and Buff and ab initio quantum mechanical techniques. The Kirkwood-Buff (KB) theory is a rigorous formalism which is free of any of the - proximations usually used in the thermodynamic treatment of multicomponent systems. This theory appears to be very fruitful when applied to the above mentioned “difficult” systems.




Proceedings of the 4th International Conference on Separations Science and Technology


Book Description

This book presents the latest achievements of separation science and technology. It highlights the application of separation with regard to problems of current interest, such as the protection of the environment and the development of emerging technology, including chemical engineering, biotechnology, renewable energy sources and recycling of materials.




Design and Control of Distillation Systems for Separating Azeotropes


Book Description

Hands-on guidance for the design, control, and operation of azeotropic distillation systems Following this book's step-by-step guidance, readers learn to master tested and proven methods to overcome a major problem in chemical processing: the distillation and separation of azeotropes. Practical in focus, the book fully details the design, control, and operation of azeotropic distillation systems, using rigorous steady-state and dynamic simulation tools. Design and Control of Distillation Systems for Separating Azeotropes is divided into five parts: Fundamentals and tools Separations without adding other components Separations using light entrainer (heterogeneous azeotropic distillation) Separations using heavy entrainer (extractive distillation) Other ways for separating azeotropes The distillation methods presented cover a variety of important industrial chemical systems, including the processing of biofuels. For most of these chemical systems, the authors explain how to achieve economically optimum steady-state designs. Moreover, readers learn how to implement practical control structures that provide effective load rejection to manage disturbances in throughput and feed composition. Trade-offs between steady-state energy savings and dynamic controllability are discussed, helping readers design and implement the distillation system that best meets their particular needs. In addition, economic and dynamic comparisons between alternative methods are presented, including an example of azeotropic distillation versus extractive distillation for the isopropanol/water system. With its focus on practical solutions, Design and Control of Distillation Systems for Separating Azeotropes is ideal for engineers facing a broad range of azeotropic separation problems. Moreover, this book is recommended as a supplemental text for undergraduate and graduate engineering courses in design, control, mass transfer, and bio-processing.




Vapour–Liquid Equilibrium


Book Description

Vapor-Liquid Equilibrium, Second Edition covers the theoretical principles and methods of calculation of equilibrium conditions from various experimental data and the elements of measuring technique, as well as the instruments for the direct determination of the equilibrium compositions of the liquid and vapor phases of the system. The book discusses the relations necessary for the thermodynamic treatment of the equilibrium between the liquid and vapor phase of a system; the concept of an ideal solution and auxiliary thermodynamic functions; and the activity and the activity coefficient. The text also describes vapor-liquid equilibrium in real systems (electrolytes and non-electrolytes) and in systems whose components (i.e. temperature, pressure, and composition of phases) mutually react according to several stoichiometric equations. The criteria of purity of substances and the methods of measuring temperature; low, medium, and high pressures; the pressures of the saturated vapors at given temperatures; and the boiling points at given pressures used in laboratory work in the field of vapor-liquid equilibrium are considered. The book also tackles the methods for the direct determination of equilibrium data (distillation, circulation, static, dew and bubble point, and flow methods). The text concludes with a review of the literature on the systems whose vapor-liquid equilibrium data had been measured and reported to the beginning of 1954. Workers in the chemical industry who deal with problems of distillation and rectification will find the book useful.




Extractive and Azeotropic Distillation


Book Description




Thermodynamics


Book Description

The simulation and optimization of processes assumes that the thermodynamic properties and phase equilibria of the mixtures concerned are well known. This knowledge is still based upon experimentation, but it is also the result of calculation methods based on the principles of thermodynamics that govern them, insure their coherence, and confer upon them a wide range of application. This text is concerned primarily with the description of these methods and their evolution. It devotes extensive space to fundamental concepts and places particular emphasis on the models that, although based on simplified concepts of the subject matter at the molecular level, have predictive character. Computational examples are used to explain the application of these concepts and models. Contents: 1. Principles. Thermodynamic functions. The ideal gas. 2. Properties of pure substances. 3. Predicting thermodynamic properties of pure substances. General principles. Corresponding states. Group contributions. 4. Equations of state. 5. Characterization of mixtures. 6. Mixtures: liquid-vapor equilibria. 7. Deviations from ideality in the liquid phase. 8. Application of equations of state to mixtures. Calculation of liquid-vapor equilibria under pressure. 9. Liquid-liquid and liquid-liquid-vapor equilibria. 10. Fluid-solid equilibria. Crystallization. Hydrates. 11. Polymer solutions and alloys. 12. Multicomponent mixtures. 13. Chemical reactions. Appendixes. Index. Bibliography.




Phase Equilibria in Chemical Engineering


Book Description

Phase Equilibria in Chemical Engineering is devoted to the thermodynamic basis and practical aspects of the calculation of equilibrium conditions of multiple phases that are pertinent to chemical engineering processes. Efforts have been made throughout the book to provide guidance to adequate theory and practice. The book begins with a long chapter on equations of state, since it is intimately bound up with the development of thermodynamics. Following material on basic thermodynamics and nonidealities in terms of fugacities and activities, individual chapters are devoted to equilibria primarily between pairs of phases. A few topics that do not fit into these categories and for which the state of the art is not yet developed quantitatively have been relegated to a separate chapter. The chapter on chemical equilibria is pertinent since many processes involve simultaneous chemical and phase equilibria. Also included are chapters on the evaluation of enthalpy and entropy changes of nonideal substances and mixtures, and on experimental methods. This book is intended as a reference and self-study as well as a textbook either for full courses in phase equilibria or as a supplement to related courses in the chemical engineering curriculum. Practicing engineers concerned with separation technology and process design also may find the book useful.