CHAPTER 1

1. Introduction to Chemical Engineering Thermodynamics CHAPTER 1 NorhanizabintiYusof Faculty of Chemical and Energy Engineering Universiti Teknologi Malaysia, 81310 UTM Johor, Johor Bahru, Malaysia Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

2. Topic Outcomes Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

3. Scope of Lecture • Overview of thermodynamic application in chemical industry • Application of thermodynamic properties and equations in chemical process Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

4. Thermodynamic Applications Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

5. Definition • The study of the effects of work, heat and energy on the system). • Only concerned with large scale observations. 0th Law: 1st Law: Work, heat, energy Thermodynamic equilibrium, temperature 2nd Law: Entropy 3rd Law: As the T of a substance approaches absolute zero it’s entropy approaches zero Ref: NASA. Available from: http://www.grc.nasa.gov/WWW/k-12/airplane/thermo.html. (Accessed 8 Feb, 2013).

6. Applications of Thermodynamics Types of process applications of thermodynamics, namely: Combustion Power Chemical reaction equilibrium Heat balances Phase equilibrium Ref: Edmister W C (1945) Applications of Thermodynamics to the Process Industries. Journal of Chemical Education. pp13 - 19

7. Chemical Engineer & Thermodynamics Why is thermodynamics useful to chemical engineers? Calculation of heat and work requirements for physical and chemical processes. Physical processes (e.g. distillation) • Heat transfer • Separation process • Chemical reactions • Mass transfer Determination of equilibrium conditions Transfer of chemical species between phases Ref: Girard-Lauriault P-L. Chemical Engineering Thermodynamics – CHEE220. (Accessed 8 Feb, 2013); Selis Ö. KMU 220 - Chemical Engineering Thermodynamics (Accessed 8 Feb, 2013)

8. Chem. Engineer & Thermo. (Cont.) • Deals with driving force • Does not deal with RATEs of physical or chemical phenomena. Chemical kinetics helps evaluate “how fast”. Thermodynamics permits to determine “how far” processes will proceed. The 2 concepts are at the base of many of the considerations of Chemical Engineers. Ref: Girard-Lauriault P-L. Chemical Engineering Thermodynamics – CHEE220. (Accessed 8 Feb, 2013); Selis Ö. KMU 220 - Chemical Engineering Thermodynamics (Accessed 8 Feb, 2013)

9. Examples Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

10. Manufacture of Ethylene Glycol • CATALYTIC OXIDATION REACTION • Most effective when carried out at T ≈ 250 C O C a t a l y s t H C C H + H C C H 1 / 2 O 2 2 2 2 2 Desired reaction H = 24.7 kcal/gmole Need to be heated to 250 C before enter the reactor • To design the preheater • MUST KNOW HOW MUCH HEAT IS TRANSFERRED Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

11. Undesired Reaction • Tend to raise the temperature ↑T Combustion reaction ↑ H = 320 kcal/gmole + H C C H 3 O 2 C O + 2 H O 2 2 2 2 2 Heat is removed from reactor → T does not rise much above 250 C • To design the reactor • REQUIRES KNOWLEDGE OF THE RATE OF HEAT TRANSFER Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

12. Hydrolysis Reaction Recovered by distillation, vaporization & condensation • Heat evolved because of • Phase change • Dissolution process • Hydration reaction between the dissolved ethylene oxide and H2O Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

13. CSTRs with Heat Exchanger • Continuous-flow reactors • At steady state, • CSTR with heat exchange Ref: Fogler H S (1999). Chapter 8: Elements of Chemical Reaction Engineering, 3rd Ed. Prentice Hall. Pp 426 – 477; CSTR: Continuous stirred-tank reactor.

14. Determination of X & T Elementary irreversible liquid phase reaction A  B • Algorithm • Calculate XMB Design equation Rate law Stoichiometry Combining • Plot X vs. T • Energy Balance (Calculate XEB) X • Non-adiabatic XEB XMB T Ref: Fogler H S (1999). Chapter 8: Elements of Chemical Reaction Engineering, 3rd Ed. Prentice Hall. Pp 426 – 477; X: Conversion, T: Temperature; EB: Energy balance; MB: Mole balance.

15. Properties & Equations Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

16. Thermodynamic Properties The thermodynamic properties required for the many fluids handled in the process industries include: • Densities • Critical state • Entropies • Free energies • Vapor pressures • Fugacities • Enthalpies • Some of these properties • →experimentally determined • Others are computed from basic experimental data • →thermodynamic equations. Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

17. Some Basic Relations in Thermodynamics First law: Second law: Phase equilibrium relations: Chemical reaction equilibrium: Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

18. Dimensions & Units Note: Appendix A: Table A.1, Conversion factors Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

19. Prefixes for SI Units Note: Appendix A: Table A.1, Conversion factors Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

20. Measures of Amount & Size • 3 basic measures • Mass, m (kg) • Number f moles, n (mol) • Total volume, Vt (m3)v 4 derivatives • Specific volume, • Molar volume, • Specific density, • Molar density, Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

21. Force (Newton 2nd Law) Force (N = kg ms-2), defined as that force which accelerates 1 kg mass 1.0 ms-2 Mass (kg) SI units: Acceleration(ms-2), 1 ms-2 = 3.20808 (ft)(s)-2 The acceleration of gravity a = g = 9.81ms-2 Force (Ibf), 1 Ibfrepresents the force that accelerates 1 Ibmat a = 32.1740 (ft)(s-2) Mass (Ibm) English units: Acceleration(ft)(s)-2 32.1740 (Ibm)(ft)(Ibf)-1(s)-2 Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

22. Temperature Temperature scale Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

23. Relationship Among T Scales Celsius Kelvin Fahrenheit Rankine Steam point Ice point Absolute zero Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

24. Pressure Defined as the normal force exerted by a fluid on a surface per unit area of the surface. Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

25. Measurement Method Manometer Dead-Weight Gauge To pressure source Weight Pan Piston h Cylinder Oil To pressure source h - the relative height of the fluid; ρ - the fluid density; g - the local acceleration of gravity. m -the mass of the piston, pan and weights; g - the local acceleration of gravity; A - the cross-sectional area of the piston. Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

26. Pressure (Cont.) Gauge Pressure vs. Absolute Pressure Readings from most pressure gauges and the manometers correspond to gauge pressures which are the difference between the pressure of interest and the pressure of the surrounding atmosphere. P (absolute) = P (gauge) + P (barometric) Different SI units for Pressure 1 kPa = 103 Pa 1 MPa = 106 Pa 1 torr = 1 mm Hg = 133.32 Pa 1 atm = 101325 Pa = 101.325 kPa = 0.101325 MPa = 760 mm Hg = 760 torr = 14.7 psi 1 bar = 105 Pa = 0.986923 atm Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

27. Work Push-PullWork Work done by the force F over the distance of (l2 – l1) • Sign of the work: • +vewhen the displacement dlis in the same direction as the applied force. • -vewhen they are in opposite directions. Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

28. Work (Cont.) PV Work • Sign of the work: • +ve for compression • -ve for expansion. Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

29. Calculation of PV Work Graphicalmethod Relationship between P and V Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

30. Energy Energy is something that a body can store, and which it can receive or give away as work or heat. Thus, energy, work and heat are closely related. Work and heat are “energy in transit”, and are never regarded as residing in a body. Energy, work and heat have the same units: Joule (SI) or lb ft (English) Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

31. Kinetic Energy (EK) Consider a body of mass m, acted upon by a force F, is displaced a distance dl during a time interval of dt, when it gains in velocity from u1 The work done by the F is, Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

32. Potential Energy (EP) Consider a body of mass m, acted upon by a force F = mg, is raised from position z = z1 to z = z2. The total work done by the F is Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

33. Energy Conservation Consider a body of mass m, falls freely from position z = z1to z = z2, where the body gains in velocity u1 → u2. In this process, the body gains in kinetic energy is the work done by the force of gravity, i.e., While in this process, the change in the body’s potential energy is EP = (mgz) = (mgz2 – mgz1) Thus, EK + EP = (mgz1 – mg2) + (mgz2 – mgz1) Therefore, for purely mechanical processes without friction, the energy conserves, i.e., or Chemical Reaction Engineering Group, Universiti Teknologi Malaysia

34. Heat Heat (Q) always transfers from a high temp. body to a lower temp. one. The rate of heat transfer ( ) is proportional to the temp. difference ΔT Like work, heat exists only as “energy in transit” from one body to another or between a system and its surroundings. When energy in the form of heat is added to a system, this part of energy is stored NOT as heat, but as kinetic and potential energy of atoms/molecules in the system. Units of heat Chemical Reaction Engineering Group, Universiti Teknologi Malaysia