Chemical Thermodynamics for Industry

by Trevor Letcher (Editor)

Overview

Chemical Thermodynamics for Industry presents the latest developments in applied thermodynamics and highlights the role of thermodynamics in the chemical industry. Written by leading experts in the field, Chemical Thermodynamics for Industry covers the latest developments in traditional areas such as calorimetry, microcalorimetry, transport properties, crystallization, adsorption, electrolyte systems and transport fuels, It highlights newly established areas such as multiphase modeling, reactive distillation, non-equilibrium thermodynamics and spectro-calorimetry. It also explores new ways of treating old technologies as well as new and potentially important areas such as ionic liquids, new materials, ab-initia quantum chemistry, nano-particles, polymer recycling, clathrates and the economic value of applied thermodynamics. This book is aimed not only at those working in a specific area of chemical thermodynamics but also at the general chemist, the prospective researcher and those involved in funding chemical research.

Product Details

ISBN-13:	9780854045914
Publisher:	RSC
Publication date:	10/05/2004
Pages:	294
Product dimensions:	6.15(w) x 9.20(h) x (d)

About the Author

Rakesh Kumar Sharma is Professor and Coordinator of Green Chemistry Network Centre, University of Delhi, India.

Read an Excerpt

Chemical Thermodynamics for Industry

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By Trevor Letcher

The Royal Society of Chemistry

Copyright © 2004 The Royal Society of Chemistry
All rights reserved.
ISBN: 978-1-84755-041-5

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CHAPTER 1

Non-Equilibrium Thermodynamics for Industry

SIGNE KJELSTRUP, AUDUN RØSJORDE AND EIVIND JOHANNESSEN

1 What Can Non-Equilibrium Thermodynamics Offer?

Non-equilibrium thermodynamics (NET) offers a systematic way to derive the local entropy production rate, σ of a system. The total entropy production rate is the integral of the local entropy production rate over the volume, V, of the system, but, in a stationary state, it is also equal to the entropy flux out, JoS, minus the entropy flux into the system, JiS:

[MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (1)

The entropy flux difference and the integral over σ can be calculated independently, and they must give the same answer. The entropy production rate governs the transport processes that take place in the system. We have

[MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (2)

where Ji and Xi are conjugate flux-force pairs. Each flux is a linear combination of all forces:

[MATHEMATICAL EXPRESSION NOT REPRODUCIBLE IN ASCII] (3)

This means that NET gives flux equations in agreement with the second law of thermodynamics, and that the theory offers a possibility, through Equation (1), to check for consistency in the models that are used.

The usefulness of NET in describing industrial problems has been questioned, because these problems are frequently non-linear. It is then important to know that the flux–force relations in Equation (3) also describe non-linear phenomena. The phenomenological coefficients Lij can, for instance, be functions of the state variables. By including internal variables in the thermodynamic description, one can extend the application of NET to activated processes; see Chapter 2. For this reason, NET appears today as a non-linear and versatile theory that applies to many practical conditions. It is a misunderstanding that flux equations need to be linear on the global level.

The total entropy production rate times the temperature of the environment is equal to the exergy destruction rate in a process. Processes with small losses in exergy have a high second law efficiency. A high second law efficiency, or exergy efficiency, is seldom a specific aim in process design. An increasing worldwide concern with CO2 emission may change this. Multiobjective optimisation, with small entropy production as one target, may then be interesting in chemical engineering design.

2 Developments and Status of NET

Non-equilibrium thermodynamics was founded by Onsager. The theory was further elaborated by de Groot and Mazur and Prigogine. The theory is based on the hypothesis of local equilibrium: a volume element in a non-equilibrium system is in local equilibrium when the normal thermodynamic relations apply to the element. Evidence is emerging that show that many systems of interest in the process industry are in local equilibrium by this criterion. Onsager prescribed that each flux be connected to its conjugate force via the extensive variable that defines the flux.

Onsager assumed that the variables and the rate laws were the same on the macroscopic and the microscopic level; this is the so-called regression hypothesis. Also using the assumption of microscopic reversibility, he proved the reciprocal relations:

Lij = Lji (4)

These assumptions restrict the validity of NET, but as stated above, they have a wide range of validity. It has long been known that the Navier–Stokes equations are contained in NET. More recently, NET has been extended to deal with transport across surfaces, quantum mechanical systems, and mesoscopic systems; see Chapter 2. We have chosen to illustrate NET with cases of transport through surfaces in the following sections.

(Continues...)

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Excerpted from Chemical Thermodynamics for Industry by Trevor Letcher. Copyright © 2004 The Royal Society of Chemistry. Excerpted by permission of The Royal Society of Chemistry.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

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Table of Contents

Front matter;Forword;Preface;Contents;Contributors;None-equilibrium thermodynamics for industry;A modelling technique for non-equilibrium metallurgical processes applied to the LD converter;Multiphase thermodynamics of pulp suspensions;Reactive distillation;Theromodynamic properties from quantum chemistry;Thermodynamics of natural gas clathrate hydrates;Ionic liquids in separation processes;Spectrocalorimetric screening for complex process optimization;Microcalorimetry for the pharmaceutical industry;Isothermal flow-microcalorimetry: Principles and application for industry;Transport properties and industry;Micro- and nano-particles production using supercritical fluids;Calorimetric measurements of thermophysical properties for industry;Plastic recycling;Industry perspective on the economic value of applied thermodynamics and the unmet needs of AspenTech clients;Thermodynamics of new materials;Thermodynamic prediction of the formation and composition ranges of metastable coating structures in PVD processes;Thermodynamics of the nano-sized particles;Theromodynamics of electrolyte systems of industry;Thermodynamics of crystallization;Thermodynamics of adsorption;Mesoscopic non-equilibrium thermodynamics of polymer crystallization;Applied thermodynamics for petroleum fluids in the refining industry;Subject Index

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From the Publisher

This welcome collection provides an introductory survey of how and where chemical thermodynamics serves to advance the frontiers of chemical technology.

Editorial Reviews

This welcome collection provides an introductory survey of how and where chemical thermodynamics serves to advance the frontiers of chemical technology.

38 (2006) 503 (John M Prausnitz) Journal of Chemical Thermodynamics

This welcome collection provides an introductory survey of how and where chemical thermodynamics serves to advance the frontiers of chemical technology.

From the Publisher