Post on 03-Jun-2018
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CENG 101
Lecture 1. Chemical Engineering Processes (5 h)
Learning Objectives:
(1) Introduction to Chemical Engineering and Processes
(2) Chemical Engineering Calculation
Units and conversion
Measurements and calculation
Dimension and dimensionless quantities
Data Presentation and analysis
(3) Processes and Process Variables
Mass and volume flow
Chemical compositionTemperature and pressure
Learning Guides:
(1) Lecture handouts
(2) Chapters 1-2 of Textbook: Elementary principles of
chemical processes
CENG 101
Lecture 1. Chemical Engineering Processes (5 h)
Learning Objectives:
(1) Introduction to Chemical Engineering and Processes
(2) Chemical Engineering CalculationUnits and conversion
Measurements and calculation
Dimension and dimensionless quantities
Data Presentation and analysis
(3) Processes and Process Variables
Mass and volume flow
Chemical compositionTemperature and pressure
Learning Guides:
(1) Lecture handouts
(2) Chapters 1-2 of Textbook: Elementary principles of
chemical processes
Chemical Engineering
(1) Chemical Engineering involves taking natural raw materials and
transforming them into useful products:
Crude Oil
Refinery
Phy
sicaltr
ansformatio
ndistillation
Chemical transformation
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Chemical Engineering Processes may involve
(1) Transport of materials
(2) Physical transformation of materials
Distillation
Smelting
(3) Chemically transformation of materials
Chemical Engineering Processes may involve
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(4) Waste reduction, pollution reduction and abatement
Chemical Engineering Processes may involve
Wastewater treatment
Recycling
(5) Understanding of energy generation and transformation
Chemical Engineering Processes may involve
(a) Efficiency of a process
(b) Phase equilibria
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(c) Reaction
Chemical Engineering Processes may involve
(d) Physical properties of materials
Conductivity
Crystal shape and size
Self-assembly structures
Protein folding
Chemical Engineering Processes may involve
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Discovery
Product
Chemical
Engineering
From Research to Product
(1) What is the product ? Who is the customer ?
- Better synthetic rubber for athletic shoes
- Nike company
We do not make a lot of things you use, but
we make it better . 3M
(2) How much will they pay ? How much should it cost ?
- Market analysis, consultation with main target
customer
- Account for the financing the building or refurbishing
of production plant, cost of raw materials and operationcost.
(3) How do we produce it ? (Process)
- Understand the basic chemistry of the reaction
A + B + Energy Product + D + heat
Guide for developing a production process
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(1) Mix the reactant A and B
Process Design and Development
ReactorA + B Product + C
Heat
(a) use giant test tube
(b) batch reactor
(c) tube reactor
(2) Design and build the reactor
- Tubular reactor
Size ?
Material ?
Stainless steel?
Glass-lined for corrosive reaction
Heating ?Electrical heater, heat exchanger or steam jacket
Process Design and Development
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(3) Reactant A & B
State of Material: Solid, liquid or gas ?
Process Design and Development
ReactorA + B Product + C
Heat
(3) Reactant A & B
Buy or produce ? $$ ?
Purity ?
Transportation ?
Solid reactant A
Process Design and Development
Crusher to reduce particle size
and promote reaction
Screw pump to transport reactant A
to the reactor
Extractor to remove
impurities
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(4) Product
Process Design and Development
Reactor Product + C
Heat
Raw Material B
Separator 2
Raw Material A
Separator 1
Sold the product as is ?
Or purify and get higher price ?
(5) By-product C, unreacted A & B
Process Design and Development
Reactor
Heat
Raw Material B
Separator 2
Raw Material A
Separator 1
Product 2
Separator 4
Product
Separator 3
Separate and sell ? Or separate and recycle for reuse ?
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(6) Safety and Environment
Automate Process ?
Safety guidelines and precautions ?
Waste reduction and treatment ?
Release guidelines ?
Community action group ? Education ?
Process Design and Development
http://www.eng.auburn.edu/users/tplacek/courses/2100/HowToSucceed.html
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(1) Fundamental dimensions length, mass and time
Metric unit
MKS: meter (m), kilogram (kg) and second (s)
cgs: centimeter (cm), gram (g) and second (s)
English unit
foot (ft), poundmass (lbm) and second (sec)
Conversions
1 m = 100 cm
= 3.28 ft = 39.37 in
1 kg = 1000 g
= 2.204 lbm
1 s = 1 sec
(2) Derived dimensions based on primitive units
(a) Force
F = mass x acceleration = ma
Metric unit MKS: Newton (N) English unit: poundal (lbf)
cgs: dyne
Conversions
1 N = 1 kg m s-2
= 105 dynes
= 0.2248 lbf
Dimensions and Units in Chemical Engineering
http://www.chemie.fu-berlin.de/chemistry/general/units_en.html
(b) Pressure
P = force/area = F/A
Metric unit MKS: Bar (bar) English unit: atmosphere (atm)
cgs: Pascal (Pa)
Conversions
1 bar = 105 kg m-1 s-2 = 105N m-2
= 105 Pa = 102 kPa
= 106 dyne cm-2
= 0.986 atm = 14.504 psia = 750 torr
Dimensions and Units in Chemical Engineering
http://www.chemie.fu-berlin.de/chemistry/general/units_en.html
1 torr = 1 mm Hg1 atm = pressure exerted by the air at
see level
1 atm = 760 mm Hg
1 atm = 14.7 psia
1 psia = 1 poundal per square inch
absolute
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(c) Temperature
Metric unit: Kelvin (K) English unit: Rankine (R)
Conversions
T (K) = t(C) + 273 = T(R)/1.8
T (R) = t(F) + 460
t(F) = 1.8 t(C) + 32
Dimensions and Units in Chemical Engineering
Zeroth Law of Thermodynamics
(d) Energy
E = force x distance = Fl
Metric unit MKS: Joules (J) English unit: ft-lbf and BTU
cgs: Erg (erg)
Conversions
1 J = 1 kg m-2 s-2 = 1 N m
= 10 cm3 bar
= 107 dyne cm = 107 erg
= 0.239 cal
= 0.7376 ft-lbf
= 9.478 x 10-4 BTU
Types of Energies:
Stored Energies: Internal energy (energy stored in molecules)
Potential energy (configurational energy)
Kinetic energy (motion)
Transient Energies: Work (mechanical work)
Heat
Dimensions and Units in Chemical Engineering
macroscopic
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(1) Kinetic Energy energy stored in moving objects
Ek = 1/2 mu2
Mechanical Energies
(2) Potential Energy energy stored in objects due to their relative
position or configuration.
Gravitational potential energy: Ep = mgz
Elastic potential energy: Ep = 1/2kx2
Mechanical Energies
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energy stored within the molecule as translational, rotational and
vibrational energies. Change in the internal energy is usually
manifested by a change in the temperature.
U = f(T)
Internal Energy
translational rotational vibrational
Energy transfer between system and surrounding occurs either in
the form of work or heat
Work (W) refers to mechanical work
W = Fdl
Heat (Q) refers to energy transferred from a hot to a cold object.
Work and Heat
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Enthalpy and Heat
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(1) Average (Mean) and Median
Engineering Measurements
http://bell.mma.edu/~jbouch/Glossary/Precision.html
0
5
10
15
20
25
30
35
52 54 56 58 60 62 64 66 68
52 1
54 4
56 7
58 20
60 35
62 15
64 9
66 2
68 4
Measurement frequency
Average = 60.11 60
Median = 58.9 59
(2) Precision and Accuracy
(1) Precision
is denoted by the number of significant figures in the data
Engineering Measurements
http://bell.mma.edu/~jbouch/Glossary/Precision.html
(2) Range, sample variance, sample standard deviation
3.4 x 104 has 2 significant figures
3.40 x 104 has 3 significant figures
3.400 x 104 has 4 significant figures
Mathematical Operations(1) Multiplication and division
7.29 0.4 = 2.916 2.9
8 x 100 2.00 = 4.00 4 x 100
(2) Addition and substraction
7.29 + 0.401 + 3.1 = 10.791 10.8
50
54
58
62
66
70
0 5 10 15 20
RUN
Measu
rements
X
X + Sx
X - Sx
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Individual Problems
Chapter 2:Problem 2.2
Chapter 2: Problem 2.13
Chapter 2: Problem 2.35
Team ProblemChapter 3: Problem 3.13
Homework # 1 Feb 14, 2003
Feb 28, 2003(1) Density(mass/volume), specific volume (volume/mass)
is given by kg/m3, g/cm3, lbm/ft3
Chemical Engineering Measurements
http://bell.mma.edu/~jbouch/Glossary/Precision.html
Density depends on temperature as material expands during
heating
e.g., VHg(T) = V0(1 + 0.18182 x 10-3T+ 0.0078 x 10-6T2)
Perrys Chemical Engineers Handbook
Specific density (/ref)
usually uses water at 4C as reference
ref = 1000 kg/m3
1.000 g/cm3
62.43 lbm/ft3
Self-study:
(1) Find out about the units Baume, degree API and degree Twaddell
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(1) Density(mass/volume), specific volume (volume/mass)
is given by kg/m3, g/cm3, lbm/ft3
Chemical Engineering Measurements
http://bell.mma.edu/~jbouch/Glossary/Precision.html
Density depends on temperature as material expands during
heating
e.g., VHg(T) = V0(1 + 0.18182 x 10-3T+ 0.0078 x 10-6T2)
Perrys Chemical Engineers Handbook
Specific density (/ref)
usually uses water at 4C as reference
ref = 1000 kg/m3
1.000 g/cm3
62.43 lbm/ft3
Self-study:
(1) Find out about the units Baume, degree API and degree Twaddell
(3a) Composition:
Chemical Engineering Measurements
Mass fraction: xA = mass of A/total mass of mixture
Mole fraction: xA = mole of A/total mole of mixture
(3b) Concentration:
Mass concentration = mass of A/volume of mixture
Mole concentration = mole of A/volume of mixture
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(4) Pressure (force/area)
is given by bar, Pa, lbf/ft2
Chemical Engineering Measurements
Hydrostatic pressure
P = P0 + gh
P0
gh
PHead
P = gh
Manometer
Example 8. Calculate the pressure a scuba diver experience at 100m beneath the surface of the ocean.
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Example 9. The manometers shown in the figure was used tomeasure the pressure at point 1 and 2 along a section of a piping.
Please determine the value of P1 and P2 in Psia.