Chemical Engineering Thermodynamics (ChE 7120)
Lecture – 1
Introduction to the course and basics principles
Know Your Instructor: Prof. B. Bharti
PhD: 2009-2012
Postdoc: 2012-2016
Assistant Prof.: 2016- 2022
Associate Prof.: 2022-present
Postdoc: 2014
BS: 2004-2007
MS: 2007-2009
Bharti Research Group: 2016-present
Environmental chemical science
Bio-nano interactions
10
5
10
3
10
1
Field driven effects
Intensity I(q) / a.u.
9.6
8.3
6.5
4.5
3.0
10
-1
10
-3
10
-5
pH
DS = 7 nm
0.1
1
q / nm
Lee, BB et al. ACS Appl. Mater. Interf., 2018
Lee, BB et al. ACS Sustainable Chem Eng. 2021
Al Harraq, BB et al. ACS Env. Au 2022, 2023
Meissner, BB et al. Soft Matter, 2019
Lee, BB et al. Langmuir 2021
Lignin NPs for oil herding and microplastics
Binding of proteins on nanoparticles
-1
4
Lee, BB et al. Nat. Commun. 2019
Al Harraq, BB et al. Science Advances 2020
Al Harraq, BB et al. Commun. Chem. 2022
Active transport and self-propulsion of colloids
• 6 Graduate students
• 2 Undergraduate students
• Up to 3 graduate students
may join in Fall-2023
Group members: 2023
3
Syllabus and policies
Textbook
• Prausnitz, Lichtenthaler and Gomes de Azevedo, Molecular
Thermodynamics of fluid-phase equilibria, 3rd edition, Prentice Hall
1999.
Supplementary reading
• Stanley I. Sandler, “Chemical, Biochemical, and Engineering
Thermodynamics” 4th ed., John Wiley & Sons, 2006
• Milo D. Koretsky, “Engineering and Chemical Thermodynamics” 2nd
edition, Wiley, 2013
• T. L. Hill, An Introduction to Statistical Thermodynamics (1986) Dover
Publications
• J. N. Israelachvili, Intermolecular and Surface Forces, 2nd edition
(1998) Academic Press.
• D. A. McQuarrie, J. D. Simon, J. Choi, Physical Chemistry: A Molecular
Approach (1997) Univ. Science Books.
Grade calculations: A weighted average numerical grade will be
calculated as follows:
• Mid-term exams = 30%
• Final exam = 30%
• Term paper and presentation = 40% (20% each)
Numerical
≥98
Score
Letter Grade A+
97.993
A
92.990
A-
89.987
B+
86.983
B
82.980
B-
79.977
C+
76.973
C
72.970
C-
69.967
D+
66.963
D
62.9- <60
60
4
DF
Course contents
Part 1: Classical thermodynamics
Laws of thermodynamics
Vapor-liquid and multiphase equilibria
Thermodynamics of mixtures
Reaction equilibria
Part 2: Molecular and statistical thermodynamics
Kinetic theory of molecules
Introduction to statistical thermodynamics
Intermolecular interactions
Lattice models of mixtures and polymers
Part 3: Selected topics
Surface and interfacial thermodynamics
Thermodynamics of biological molecules
5
What is Thermodynamics?
Thermodynamics
From Greek, ‘therme’= Heat
From Greek, ‘dynamis’ = strength, power
• Original definition from 1700s: The study of how to convert heat into ‘useful work’
• Thermodynamics is play a crucial role in every industry and process.
• It is also applicable to atoms and molecules as well as to the planets and stars.
Petroleum
Electronics
Food
Biomedicine
6
Thermodynamics and kinetics
Thermodynamics
• Given initial and final states, calculate change
of properties between them
• Pressure, temperature, density, energy, etc.
• Given initial state, what is the final equilibrium
state?
• No idea of time (how long it will take to get
from initial to final state)
Kinetics / transport (fluid mechanics, heat and mass transfer, reaction kinetics)
• Time is important
• Flow rates; how fast heat is transferred; how long will it take to separate two
components from a mixture; time to react a significant amount of A + B into C
• Depend on different variables (temperature, pressure, concentration, type of
equipment, how close we are to equilibrium, etc.)
• How fast we can reach equilibrium
7
Basic Thermodynamic Definitions
Driving Force
Transferred
Quantity
"Allowing"
boundary
"Preventing"
boundary
ÑT
Q (heat)
Diathermal
Adiabatic
-Ñ P
V (volume)
Movable
Rigid
ÑC
M (mass) or
Ni (moles)
Permeable
Impermeable
Ñe
q (charge)
Unshielded
Shielded
Intensive
variables
Extensive
variables
V
Conversion:
=V
Extensive/extensive = intensive N i
Types of equilibria: Stable, Metastable, Indifferent, Kinetically
stable, Quasi-equilibrium
Homogenous vs. heterogeneous systems: Phases, phase boundaries
and phase equilibria
8
Heat, Work, Mass and Energy
Internal Energy U: Stored in the system because of molecular motion and interactions
Volume work d W = - P d V
V2
W = -ò P dV
V1
Heat Q
For a closed system: DU = Q + W
dU = dQ + dW
Simplest expressions of the first law: although energy assumes many
forms, and freely converts between them, the total quantity of energy is
constant.
Shaft work
W s = ± t w
Kinetic energy
Ek =
Potential energy
1
M v2
2
Ep = M g D z
9
Mass and Energy Balances – Open System
J1A 1
M(t)
J2 A 2
Full mass balance:
J3 A 3
W
dM
= å M k (mass) or
dt
k
Q
dN
= å N k (moles)
dt
k
Full energy balance:
ü
d ì
v2
v2

ˆ
íU + M ( + g Dz )ý = å M k (U + + g Dz ) k + Q + W s - P V + å M k ( P Vˆ ) k
dt î
2
2
k
þ k
10
Energy Balances – Enthalpy
Define Enthalpy: H º U + P V
then:
2
ü
d ì
v2
v
íU + M ( + g Dz ) ý = å M k (Uˆ + + g Dz ) k + å M k ( P Vˆ ) k + Q + W s - P V
dtî
2
2
k
þ k
ü
d ì
v2
v2

ˆ
íU + M ( + g Dz ) ý = å M k ( H + + g Dz ) k + Q + W
dtî
2
2
þ k
Uniform system, no shaft work,
low to medium stream velocities
molar basis
dU
= å N k H k + Q + P V
dt
k
dU =H d N + d Q - P dV
Differential expression - not as well defined mathematically, but extremely useful
11
Example of Enthalpy Use – Throttling Process
(Joule-Thomson expansion)
P1, T1
P2, T = ?
Valve or
porous plug
Insulated
pipe
Open, steady state system:
2
v
å M k ( Hˆ + 2 + g Dz ) k + Q + W s = 0
k
Constant
Hˆ 1 (T1 , P1 ) = Hˆ 2 (T2 , P2 )
Negligible
none
none
H 1 (T1 , P1 ) = H 2 (T2 , P2 )
Constant enthalpy (isenthalpic) process
12
Example and exercise
What happens when methane at 20 MPa and 340 K is throttled to 0.5 MPa ?
What if throttling is done from 10 MPa and 340 K to 0.1 MPa ?
13
State variables and equations of state
Any of the intensive variables of a system at equilibrium is state variable
Examples: T, P, U, H, S, density r, polarisability, etc.
The state of the system is described with a single
point in a multidimensional space
T
H
P
U
V
S
Allows constructing multiparametric diagrams and tables (e.g. steam tables).
In order to calculate such relations for a given substance, we need the equations of state.
Generic example - ideal gas
PV = R T
14
Thermodynamic Properties of Matter
Relation between the internal energy of a given substance and temperature
(d U )V = (d Q )V
Constant volume:
Constant-volume heat capacity
Constant-pressure heat capacity
For ideal gas:
CV =
1
N
(d U + P dV )P = (d H )P
Constant Pressure:
PV = R T
dU =d Q - P dV
= N CV ( d T )V
CP =
æ ¶U ö æ ¶U ö
çç
÷÷ = çç
÷÷
¶
T
¶
T
è
øV è
øV
= N C P (d T ) P
1
N
æ¶ H ö æ¶ H ö
çç
÷÷ = çç
÷÷
¶
T
¶
T
è
øP è
øP
U = U (T ) only;
CV* (T ) =
dU
dT
C P* (T ) =
d H dU
dT
=
+R
= CV* (T ) + R
dT
dT
dT
H = U (T ) + P V = U (T ) + R T = H (T )
15
Process calculations with ideal gas
(1) N CV d T = d Q - P d V or (2)
N (CP - R ) dT = d Q - P d V
(3) - PdV = dW = - N R T d V
V
Isochoric (Constant-V) process: d V = 0, (1)
d Q = d U = N CV d T
Q = D U = N ò CV d T
è
Isobaric (Constant-P) process, N R dT = P d V (2)
d Q = d H = N CP d T
Q = D H = N ò CP d T
è
Isothermal (Constant-T) process, (1)
dV
- dQ = dW = - R T
V
è
- Q = DW = - R T ln
V2
P
= R T ln 2
V1
P1
Adiabatic (Q = 0) process
N CV d T = - N R T
dV
V
è
also
dT
R dV
= T
CV V
T2 æ P2 ö
= çç ÷÷
T1 è P1 ø
R
CP
è
and
ln
T2
V
R
= ln 2
T1
CV
V1
P2 æ V1 ö
=ç ÷
P1 çè V2 ÷ø
è
T2 æ V1 ö
=ç ÷
T1 çè V2 ÷ø
CP
CV
16
R
CV
Summary: Lecture 1
• First law
dU = dQ + dW
• Enthalpy
H º U + PV
• Mass and energy balances
• Heat capacities
• Process calculations
2
v
å M k ( Hˆ + 2 + g Dz ) k + Q + W s = 0
k
æ¶ H ö æ¶ H ö
çç
÷÷ = çç
÷÷
C P (T ) = CV (T ) + R
¶
T
¶
T
è
øP è
øP
V
P
- Q = DW = - R T ln 2 = R T ln 2
V1
P1
CP =
1
N
17