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Thermodynamics Review and Theory Boxi Chen Khang Tran Roger Chiquito Perez Sandra Nouketcha

Thermodynamics Review and Theory Boxi Chen Khang Tran Roger Chiquito Perez Sandra Nouketcha Shanshan Jin Olufunke Lawal. Outline. What is thermodynamics The laws of thermodynamics Chemical-reaction equilibria ( gibbs- free energy Thermodynamics models (Aspen) Conclusion Questions.

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Thermodynamics Review and Theory Boxi Chen Khang Tran Roger Chiquito Perez Sandra Nouketcha

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  1. Thermodynamics Review and Theory Boxi Chen Khang Tran Roger Chiquito Perez Sandra Nouketcha Shanshan Jin Olufunke Lawal

  2. Outline • What is thermodynamics • The laws of thermodynamics • Chemical-reaction equilibria ( gibbs- free energy • Thermodynamics models (Aspen) • Conclusion • Questions

  3. Introduction

  4. What is Thermodynamics? (19th century) • Power developed from heat Why is it important? • Analysis and prediction of physical systems Relationship to engineering and industry • Design systems • Unit operations - gas absorption, heat transfer • Unit processes - oxidation, catalysis

  5. 1. Laws of Thermodynamics

  6. Zeroth Law of Thermodynamics If two bodies are each in thermal equilibrium with some third body they are also in equilibrium with each other.

  7. First Law of Thermodynamics Energy is conservation, which means energy can be neither created nor destroyed, but it can be transferred or changed from one form to another.

  8. First Law of Thermodynamics The first law applies to the system and its surroundings. The energy change of the closed system equals the net energy that is transferred to heat and work.

  9. Second Law of Thermodynamics • Entropy is how organized or disorganized energy is in a system of atoms or molecules. • The state of entropy of the entire universe, as an isolated system, will always increase over time.

  10. Third Law of Thermodynamics The entropy of a system approaches a constant value (0) as the temperature approaches absolute zero (–273.15°C) .

  11. 1. Gibbs free energy

  12. Gibbs Free Energy ΔG=ΔH-TΔS Effect of temperature on Gibbs free energy • Gibbs free energy is a measure of chemical energy • It combines enthalpy and entropy into a single value • It predicts reaction spontaneity (ΔG<0) • Chemical system tend naturally towards state minimum gibbs free energy

  13. Application of Gibbs free energy • process simulation of distillation processes: Estimation of activity coefficients useful for models such as the NRTL (Non-Random Two-Liquid), UNIQUAC (UNIversal QUAsiChemical) and the Wilson model • separation processes: Absorption (where it is related with Henry’s law) • Chemical engineering kinetics and reactor designs • synthesis of nanomaterials • The Gibbs free energy is also central to crystallization processes

  14. 1. Thermodynamic Models / EOS

  15. Equations of State (EOS) • EOS are convenient tools to use to relate two or more functions of state • Many EOS are fitted empirical functions • Fitting parameters are typically functions of critical temperature and pressure, which generalizes EOS to all species that have available critical point data

  16. Common EOS Models • Ideal Gas Law • Van der Waals EOS (Modified Ideal Gas Law) • Peng-Robinson • Redlich-Kwong, Suave Redlich Kwong • NRTL • UNIFAC, UNIQUAC

  17. Why is this important? • Thermodynamic quantities may be hard to calculate otherwise • Does not involve differential equations • Many simulation software (including Aspen) utilizes these EOS to speed up calculations • When using a simulation software, it is important to choose the appropriate model

  18. 1. Applications/ Models Selection

  19. Industrial Requirements • Simplicity over complexity • Fewer models (single?) which can do more • Wide range of properties and conditions • Both thermodynamic (equilibrium and other) and transport properties needed

  20. Model Selection • Different industries use different models based on experience • Oil and gas processing → PR, SRK • High non-ideality → Specialized models • Amine sweetening unit in gas processing

  21. Model Selection (Water, alcohol, acids) Non-idealities expected Non-condensable components: Co2, N2, O2 http://www.just.edu.jo/~yahussain/files/Thermodynamic%20Models.pdf

  22. 1. Conclusion

  23. Application of Thermodynamic Theory • Thermodynamic theories and principles are used to model chemical reactions and molecular interactions • Models allow for quantitative understanding of abstract concepts • The appropriate model takes into account the relevant parameters in a given system • In industry the simplest models are the most successful • Few applicable models

  24. Sources • Hussain, Y. Thermodynamic models and physical properties. • Kontogeorgis, G. Thermodynamic models for process and product design. Center for Energy Resources Engineering.

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