Chemical Reaction Engineering
Chemical Engineering
Chemical Reaction Engineering
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.
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
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.
• A chemical species is said to have reacted when it has lost its chemical identity.
Chemical Identity
• 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
• A chemical species is said to have reacted when it has lost its chemical identity.
1. Decomposition
Chemical Identity
• A chemical species is said to have reacted when it has lost its chemical identity.
1. Decomposition
2. Combination
Chemical Identity
• A chemical species is said to have reacted when it has lost its chemical identity.
1. Decomposition
2. Combination
3. Isomerization
Chemical Identity
• The reaction rate is the rate at which a species looses its chemical identity per unit volume.
Reaction Rate
• 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
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
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
Reaction Rate• EXAMPLE: AB
rB = 0.2 mole/dm3/s
Then A is disappearing at the same rate:
-rA= 0.2 mole/dm3/s
Reaction Rate
• EXAMPLE: ABrB = 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
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
Reaction Rate
Consider species j: • rj is the rate of formation of species j per
unit volume [e.g. mol/dm3/s]
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)
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.)
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
General Mole Balance
General Mole Balance
Batch Reactor Mole Balance
CSTRMole Balance
Plug Flow Reactor
Plug Flow Reactor Mole Balance
PFR:
The integral form is:
V dFArAFA 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.
Packed Bed Reactor Mole Balance
PBR
The integral form to find the catalyst weight is:
W dFA
r AFA 0
FA
FA0 FA r AdW dNA
dt
Reactor Mole Balance Summary
Fast Forward to the Future
Thursday March 20th, 2008
Reactors with Heat Effects
Production of Propylene Glycol in an Adiabatic CSTR
What are the exit conversion X and exit temperature T?
SolutionLet the reaction be represented by
KEEPING UP
Separations
These topics do not build upon one another
Filtration Distillation Adsorption
Reaction Engineering
These topics build upon one another
Mole Balance Rate Laws Stoichiometry
Mole Balance
Rate Laws
Stoichiometry
Isothermal Design
Heat Effects
Mole BalanceRate Laws
Mole Balance
Rate LawsStoichiometry
Isothermal Design
Heat Effects
Batch Reactor Mole Balance
Batch Reactor Mole Balance
Batch Reactor Mole Balance
Batch Reactor Mole Balance
Batch Reactor Mole Balance
Continuously Stirred Tank Reactor Mole Balance
Continuously Stirred Tank Reactor Mole Balance
Continuously Stirred Tank Reactor Mole Balance
C S T R Mole Balance
CSTRMole Balance
Plug Flow Reactor
Plug Flow Reactor Mole Balance
PFR:
Plug Flow Reactor Mole Balance
PFR:
Plug Flow Reactor Mole Balance
PFR:
Plug Flow Reactor Mole Balance
PFR:
Plug Flow Reactor Mole Balance
PFR:
Plug Flow Reactor Mole Balance
PFR:
The integral form is:
V dFArAFA 0
FA
Plug Flow Reactor Mole Balance
PFR:
The integral form is:
V dFArAFA 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.
Packed Bed Reactor Mole Balance
PBR
Packed Bed Reactor Mole Balance
PBR
FA0 FA r AdW dNA
dt
Packed Bed Reactor Mole Balance
PBR
FA0 FA r AdW dNA
dt
Packed Bed Reactor Mole Balance
PBR
FA0 FA r AdW dNA
dt
Packed Bed Reactor Mole Balance
PBR
The integral form to find the catalyst weight is:
W dFA
r AFA 0
FA
FA0 FA r AdW dNA
dt
Reactor Mole Balance Summary
Reactor Mole Balance Summary
Reactor Mole Balance Summary
Reactor Mole Balance Summary
Chemical Reaction Engineering
Asynchronous Video Series
Chapter 1:General Mole Balance Equation
Applied to Batch Reactors, CSTRs, PFRs,
and PBRs
H. Scott Fogler, Ph.D.
http://www.engin.umich.edu/~cre
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
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.
StomachVG = 2.4 l
GastrointestinalVG = 2.4 ltG = 2.67 min
Liver
Alcohol
VL = 2.4 l tL = 2.4 min
CentralVC = 15.3 l tC = 0.9 min
Muscle & FatVM = 22.0 l tM = 27 min
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
The end