1. Chemical Reaction Engineering (CRE) is the field that
studies the rates and mechanisms of chemical reactions and
the design of the reactors in which they take place.
TODAY’S LECTURE
Introduction
Definitions
General Mole Balance Equation
Batch
CSTR
PFR
PBR
2. Chemical Reaction Engineering
Chemical reaction engineering is at the heart of virtually
every chemical process. It separates the chemical engineer
from other engineers.
Industries that Draw Heavily on Chemical Reaction
Engineering (CRE) are:
CPI (Chemical Process Industries)
Dow, DuPont, Amoco, Chevron
11. Developing Critical Thinking Skills
Socratic Questioning
is the
Heart of Critical Thinking
R. W. Paul’s Nine Types of Socratic
Questions
12. Let’s Begin CRE
Chemical Reaction Engineering (CRE) is
the field that studies the rates and
mechanisms of chemical reactions and the
design of the reactors in which they take
place.
13. • A chemical species is said to have reacted
when it has lost its chemical identity.
Chemical Identity
14. • A chemical species is said to have reacted
when it has lost its chemical identity.
• The identity of a chemical species is
determined by the kind, number, and
configuration of that species’ atoms.
Chemical Identity
15. • A chemical species is said to have reacted
when it has lost its chemical identity.
1. Decomposition
Chemical Identity
16. • A chemical species is said to have reacted
when it has lost its chemical identity.
1. Decomposition
2. Combination
Chemical Identity
17. • A chemical species is said to have reacted
when it has lost its chemical identity.
1. Decomposition
2. Combination
3. Isomerization
Chemical Identity
18. • The reaction rate is the rate at which a
species looses its chemical identity per unit
volume.
Reaction Rate
19. • The reaction rate is the rate at which a
species looses its chemical identity per unit
volume.
• The rate of a reaction (mol/dm3/s) can be
expressed as either
the rate of Disappearance: -rA
or as
the rate of Formation (Generation): rA
Reaction Rate
20. Reaction Rate
Consider the isomerization AB
rA = the rate of formation of species A per unit volume
-rA = the rate of a disappearance of species A per unit volume
rB = the rate of formation of species B per unit volume
21. Reaction Rate
• EXAMPLE: AB
If Species B is being formed at a rate of
0.2 moles per decimeter cubed per second, ie,
rB = 0.2 mole/dm3/s
22. Reaction Rate
• EXAMPLE: AB
rB = 0.2 mole/dm3/s
Then A is disappearing at the same rate:
-rA= 0.2 mole/dm3/s
23. Reaction Rate
• EXAMPLE: AB
rB = 0.2 mole/dm3/s
Then A is disappearing at the same rate:
-rA= 0.2 mole/dm3/s
The rate of formation (generation of A) is
rA= -0.2 mole/dm3/s
24. Reaction Rate
• For a catalytic reaction, we refer to -rA',
which is the rate of disappearance of
species A on a per mass of catalyst basis.
(mol/gcat/s)
NOTE: dCA/dt is not the rate of reaction
26. Reaction Rate
• rj is the rate of formation of species j per
unit volume [e.g. mol/dm3*s]
• rj is a function of concentration,
temperature, pressure, and the type of
catalyst (if any)
27. Reaction Rate
• rj is the rate of formation of species j per unit
volume [e.g. mol/dm3/s]
• rj is a function of concentration, temperature,
pressure, and the type of catalyst (if any)
• rj is independent of the type of reaction system
(batch reactor, plug flow reactor, etc.)
28. Reaction Rate
• rj is the rate of formation of species j per
unit volume [e.g. mol/dm3/s]
• rj is a function of concentration,
temperature, pressure, and the type of
catalyst (if any)
• rj is independent of the type of reaction
system (batch, plug flow, etc.)
• rj is an algebraic equation, not a
differential equation
34. Plug Flow Reactor Mole Balance
PFR:
The integral form is: V
dFA
rA
FA 0
FA
This is the volume necessary to reduce the entering molar flow rate (mol/s) from FA0 to the
exit molar flow rate of FA.
35. Packed Bed Reactor
Mole Balance
PBR
The integral form to find the catalyst weight is: W
dFA
rA
FA 0
FA
FA0 FA
rAdW
dNA
dt
78. Plug Flow Reactor Mole Balance
PFR:
The integral form is: V
dFA
rA
FA 0
FA
79. Plug Flow Reactor Mole Balance
PFR:
The integral form is: V
dFA
rA
FA 0
FA
This is the volume necessary to reduce the entering molar flow rate (mol/s) from FA0 to the
exit molar flow rate of FA.
106. Chemical Reaction Engineering
Chemical reaction engineering is at the heart of virtually
every chemical process. It separates the chemical engineer
from other engineers.
Industries that Draw Heavily on Chemical Reaction
Engineering (CRE) are:
CPI (Chemical Process Industries)
Dow, DuPont, Amoco, Chevron
Pharmaceutical – Antivenom, Drug Delivery
Medicine – Tissue Engineering, Drinking and Driving
107. Compartments for perfusion
Perfusion interactions between
compartments are shown by arrows.
VG, VL, VC, and VM are -tissue water
volumes for the gastrointestinal,
liver, central and muscle
compartments, respectively.
VS is the stomach contents volume.
Stomach
VG = 2.4 l
Gastrointestinal
VG = 2.4 l
tG = 2.67 min
Liver
Alcohol
VL = 2.4 l
tL = 2.4 min
Central
VC = 15.3 l
tC = 0.9 min
Muscle & Fat
VM = 22.0 l
tM = 27 min
108.
109. Chemical Reaction Engineering
Chemical reaction engineering is at the heart of virtually
every chemical process. It separates the chemical engineer
from other engineers.
Industries that Draw Heavily on Chemical Reaction
Engineering (CRE) are:
CPI (Chemical Process Industries)
Dow, DuPont, Amoco, Chevron
Pharmaceutical – Antivenom, Drug Delivery
Medicine –Pharmacokinetics, Drinking and Driving
Microelectronics – CVD
111. Reaction Rate
Consider the isomerization AB
rA = the rate of formation of species A per unit volume
-rA = the rate of a disappearance of species A per unit volume