29901 - Thermodynamics of Chemical and Biochemical Engineering T

Course Unit Page

SDGs

This teaching activity contributes to the achievement of the Sustainable Development Goals of the UN 2030 Agenda.

Affordable and clean energy Industry, innovation and infrastructure Responsible consumption and production

Academic Year 2021/2022

Learning outcomes

Knowledge about: basic Chemical Engineering Thermodynamics, main tools for process thermodynamic analysis and properties calculation of pure substances in gas and liquid phase, phase and chemical equilibria.

Course contents

The course is an introduction to Chemical Engineering Thermodynamics. Basic elements will be introduced for the characterization of physical and chemical equilibria and for the calculation of the properties of pure substances and mixtures. Final applications are heat and mass balances in simple equipment.

Requirements

A prior knowledge and understanding of basic general Chemistry and basic elements of mass balances is required to attend with profit this course. In addition, students should manage basic concepts of Thermodynamics concerning first and second Laws.Finally, students should manage basic elements of a spreadsheet (Excel).

Fluent spoken and written Italian is a necessary pre-requisite: all lectures and tutorials, and all the study material will be in Italian

Contents

1. Introduction

Central problems of Thermodynamics. Basic definitions: the “continuous”, process variables, pressure, temperature. Equilibrium and zero law. Apparatuses: closed and open, batch and continuous systems, steady and unsteady conditions. The integral balance equation of a conserved quantity. Mass balances equations (resume). Units.

2. First Law.

Internal Energy. The energy balance equation; flow work and shaft work. Enthalpy. Deformation power. Thermal energy equation.

3. Second Law

Classical Kelvin-Planck and Clausius formulations. Reversible and Irreversible processes; energy dissipation. Entropy and Entropy balance equation. Heat, Work, Heat Engines. Thermodynamic efficiency. Maximum and minimum work. Carnot Cycle. Turbines and compressors efficiency

4. Thermodynamic properties of real substances.

(p,V,T) diagrams for pure substances. Maxwell relations. Thermodynamic diagrams (p,H), (T,S) and Tables. Joule-Thompson coefficient. Vapor pressure. The molar heat of ideal gases and latent heats of phase transitions. Enthalpy of pure substances: reference state. Analysis and selection of literature data for calculations.

5. Problems of heat and mass balances for pure substances.

Adiabatic power of compression/espansion. Power cycles, refrigeration cycles, gas liquefaction. Heat exchangers, mixers.

6. Thermodynamics of multicomponent mixtures.

Partial molar properties. Maxwell equations for multi-components systems. Chemical potential. Ideal mixtures and real mixtures. Property changes of mixing. Excess free energy. Fugacity, activity, activity coefficients: definitions and relations. Raoult’s and Henry’s reference state.

Excess free energy models: Margules, Van Laar, Wilson. Discussion.

7. Equilibrium.

Phase equilibria. The Gibbs phase rule. The Clausius-Clapeyron equation.

8. Liquid-vapor equilibrium.

Raoult’s equation: the Poynting factor and simplifications. Raoult’s law for ideal mixtures. L-V equilibrium diagrams for binary systems at low to moderate pressures. (T,x), (p,x) and (y,x) diagrams for ideal systems and non-ideal systems, positive and negative deviations; lever rule applications. Azeotropes. Volatility.

Boiling point and dew point calculations for ideal and non-ideal mixtures; solution procedures and discussion of the corresponding algorithms. Calculation of equilibrium conditions for different specifications. Applications to equilibrium condensers/evaporators. The effect of incondensable compounds.

9. Liquid-liquid and liquid-liquid-vapour equilibria. (brief)

L-L equilibrium diagrams for binary systems; solubility diagrams and partial miscibility; consolute temperatures.

L-L-V equilibrium diagrams; heterogeneous azeotropes. The limiting case of completely immiscible liquids. Boiling point and dew point calculations for binary systems containing water and hydrocarbons.

10. Gas-liquid systems

Henry’s law and asymmetrical reference. Solubility of gases in water.

11. Chemical-reaction equilibria

Thermochemistry. Equilibrium criteria for chemical reactions. The standard Gibbs energy change and the equilibrium constant of a reaction. Effect of temperature. Evaluation of equilibrium constants: application and discussion about different calculation procedures, depending on the available data in literature. Approximations. Effect of pressure, inert compounds and reactants composition on the equilibrium conditions.

Calculation of equilibrium conversions in ideal gas mixtures. Material and energy balances on isothermal and adiabatic reactors.

Readings/Bibliography

  1. Teacher's notes, uploaded in the UNIBO web site “Virtual Learning Environment-VLE”.
  2. S.Sandler, Chemical, Biochemical and Engineering Thermodynamics, 4a ed, J Wiley & Sons, 2006 and 5a ed, J Wiley & Sons, 2020
  3. J. M. Smith, H.C.Van Ness, M.M. Abbot, Introduction to Chemical Engineering Thermodynamics, 5a (e/o7a ed.), Mc Graw Hill, 1996
  4. J. M. Smith, H.C.Van Ness, M.M. Abbot, M.T.Swihart, Introduction to Chemical Engineering Thermodynamics, 8a ed., Mc Graw Hill, 2018 (pdf downloadable on-line)
  5. M.W. Zemansky, M.M. Abbot, H.C.Van Ness, Fondamenti di termodinamica per ingegneri, Zanichelli, 1979

Teaching methods

In-class lessons and tutorials. A tablet is used instead of the traditional blackboard; pdf files are uploaded in the UNIBO web site “VLE”.

Assessment methods

The examination is composed of two written sections ("CLOSED BOOKS"). The sum of the scores in each part leads to the total score.

Written section: part 1. (minimum score for a passing grade=9)

A) 20 questions about basic concepts and thermodynamic porperties of pure substances (duration= 22 min); maximum score = 4

B) solution of heat and mass balances and properties calculations of pure substances in multiphase conditions (duration= 1 h -45min; maximum score = 13)

Written section: part 2. (minimum score for a passing grade=9)

A) 20 questions about basic concepts of liquid-vapor equilibria, chemical equilibria and properties of multicomponent mixtures (duration= 22 min); maximum score = 4

B) solution of heat and mass balances and properties calculations of multicomponent mixtures, including discussion of L-V diagrams and chemical equilibrium calculations. (duration= 1 h -45 min); maximum score = 13

«CLOSED BOOKS»: only pocket scientific calculator is allowed. Reference data, books, and other notes are not allowed, neither personal computer, nor mobile phones, nor tablet, etc..

Opportunities

The student can decide to attend the two written parts in different calls. It is mandatory to conclude the exam within two subsequent calls. Midterm examinations can be scheduled : the first one after 45/50 hours, the second one immediately at the end of lessons.

Office hours

See the website of Serena Bandini