“…A useful book and I strongly recommend its purchase…” Chemistry in Britain November 1998 “…Excellent little book…plenty of references to help further study.” International Pest Control, December 1998 “… carefully written and skilfully put together by acknowledged experts … a valuable reference source for everyone with an interest in plant protection, for advanced students, for scientists and others in universities, public authorities, and industry, and not least for agricultural advisers.” Angewandte Chemie International Edition, Vol 38, No 7, April 1, 1999

Chemical Thermodynamics for Industry

By Trevor Letcher

The Royal Society of Chemistry

Copyright © 2004 The Royal Society of Chemistry
All rights reserved.
ISBN: 978-0-85404-559-4

Contents

Chapter 1 Non-Equilibrium Thermodynamics for Industry S. Kjelstrup, A. Røsjorde and E. Johannessen, 1,
Chapter 2 A Modelling Technique for Non-equilibrium Metallurgical Processes Applied to the LD Converter M. Modigell, A. Traebert, P. Monheim and K. Hack, 12,
Chapter 3 Multiphase Thermodynamics of Pulp Suspensions P. Koukkari, R. Pajarre and E. Räsänen, 23,
Chapter 4 Reactive Distillation H. G. Schoenmakers and W. Arlt, 33,
Chapter 5 Thermodynamic Properties from Quantum Chemistry S.I. Sandler, 43,
Chapter 6 Thermodynamics of Natural Gas Clathrate Hydrates E.D. Sloan, 57,
Chapter 7 Ionic Liquids in Separation Processes J. Gmehling, 76,
Chapter 8 Spectrocalorimetric Screening for Complex Process Optimization F. Dan and J-P.E. Grolier, 88,
Chapter 9 Microcalorimetry for the Pharmaceutical Industry A.E. Beezer, 104,
Chapter 10 Isothermal Flow-Microcalorimetry: Principles and Applications for Industry M.A.A. O’neill, 110,
Chapter 11 Transport Properties and Industry W.A. Wakeham and M.J. Assael, 122,
Chapter 12 Micro- and Nano-particles Production Using Supercritical Fluids E. Reverchon and I. De Marco, 132,
Chapter 13 Calorimetric Measurements of Thermophysical Properties for Industry J-P.E. Grolier and F. Dan, 144,
Chapter 14 Plastic Recycling W. Arlt, 159,
Chapter 15 Industry Perspective on the Economic Value of Applied Thermodynamics and the Unmet Needs of AspenTech Clients C-C. Chen, S. Watanasiri, P. Mathias and V.V. De Leeuw, 166,
Chapter 16 Thermodynamics of New Materials M. Schroeder and M. Martin, 180,
Chapter 17 Thermodynamic Prediction of the Formation and Composition Ranges of Metastable Coating Structures in PVD Processes P.J. Spencer, 197,
Chapter 18 Thermodynamics of the Nano-Sized Particles T. Tanaka, J. Lee and N. Hirai, 209,
Chapter 19 Thermodynamics of Electrolyte Systems of Industry K. Thomsen, 219,
Chapter 20 Thermodynamics of Crystallization A.S. Teja and R.W. Rousseau, 230,
Chapter 21 Thermodynamics of Adsorption A.L. Myers, 243,
Chapter 22 Mesoscopic Non-equilibrium Thermodynamics of Polymer Crystallization D. Reguera and J.M. Rubí, 254,
Chapter 23 Applied Thermodynamics for Petroleum Fluids in the Refining Industry D. Ramjugernath and R. Sharma, 262,
Subject Index, 274,

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…)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.
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