Lecture Overviews and Notes

This page contains lecture notes from a typical Chemical Reaction Engineering class along with a student's notes. All lecture notes were prepared by Professor Scott Fogler and the student notes from Professor Fogler's class were taken by Jarrod Brown, who has given permission for them to be used. Letter from Jarrod.

Lecture 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

Applications to Chemical 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

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 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.

Decomposition CH₃CH₃→H₂+H₂C=CH₂
Combination N₂+O₂→2NO
Isomerization C₂H₅CH=CH₂→CH₂=C(CH₃)₂

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: -r_A

or as

the rate of Formation (Generation): r_A

Consider the isomerization A$rarr;B

r_A = the rate of formation of species A per unit volume

-r_A = the rate of a disappearance of species A per unit volume

r_B = the rate of formation of species B per unit volume

EXAMPLE: A→B

If Species B is being formed at a rate of 0.2 moles per decimeter cubed per second, ie, r_B = 0.2 mole/dm³/s

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

The rate law is an algebraic equation. For example for the reaction, A→B

The rate law could be of the form

General Mole Balance

Batch Reactor Mole Balance

CSTR Mole Balance

Plug Flow Reactor

Plug Flow Reactor Mole Balance

Packed Bed Reactor Mole Balance

Reactor Mole Balance Summary

Keeping Up

Reaction Engineering

These topics build upon one another

But if you cut corners like this

Then this will happen

Lecture 2

TODAY’S LECTURE

Review of Lecture 1
Solution to P1-6
Definition of Conversion, X
Develop the Design Equations in Terms of X
Size CSTRs and PFRs given –rA=f(X)
Conversion for Reactors in Series
Review the Fall of the Tower of CRE

Levenspiel Plots

Lecture 3

TODAY’S LECTURE

Block 1: Mole Balances (Review)
- Size CSTRs and PFRs given –r_A=f(X)
- Conversion for Reactors in Series
Block 2: Rate Laws
- Reaction Orders
- Arrhenius Equation
- Activation Energy
- Effect of Temperature

Levenspiel Plot

CSTR

PFR

Steps to get -r_A

Rate Law
-r_A=g(C_i)
Stoichiometry
(C_i)=h(X)
Combine to get
-r_A

Arrhenius Equation

Reaction Coordinate

Lecture 4

TODAY’S LECTURE

Block 1: Mole Balances
- Size CSTRs and PFRs given –r_A=f(X)
Block 2: Rate Laws
- Reaction Orders
- Arrhenius Equation
Block 3: Stoichiometry
- Stoichiometric Table
- Definitions of Concentration
- Calculate the Equilibrium Conversion, X_e

Levenspiel Plot

PFR

Steps to get -r_A

Rate Law
-r_A=g(C_i)
Stoichiometry
(C_i)=h(X)
Combine to get
-r_A

Lecture 5

TODAY’S LECTURE

Stoichiometry
- Stoichiometric Table: Flow
- Definitions of Concentration: Flow
- Gas Phase Volumetric Flow rate
- Calculate the Equilibirum Conversion Xe

Two steps to get -r_A=f(X)

Step 1: Rate Law

-r_A=g(C_i)
Step 2: Stoichiometry

(C_i)=h(X)
Step 3: Combine to get

-r_A=f(X)

Lecture 6

TODAY’S LECTURE

Block 1: Mole Balances
Block 2: Rate Laws
Block 3: Stoichiometry
Block 4: Combine

Examples

Liquid Phase ChE 460 Experiment : CSTR and PFR Calculation
(CH₂CO)₂O + H₂O → 2CH₃COOH
A + B → 2C
Gas Phase : PFR and Batch Calculation
2NOCl → 2NO + Cl₂
2A → 2B + C

Lecture 7

TODAY’S LECTURE

California Professional Engineers Exam

Exam is not curved, 75% or better to pass

Problem 4-12

Lecture 8

TODAY’S LECTURE

Pressure Drop:
- Liquid Phase Reactions: Pressure Drop Does Not Effect the Concentrations in Liquid Phase Rxns
- Gas Phase Reactions.
  - Epsilon not Equal to Zero
    d(P)/d(W)=..
    Polymath will combine with d(X)/f(W)=..for you
  - Epsilon = 0 and Isothermal
    P=f(W)
    Combine then Separate Variables (X,W) and Integrate
- Gas Phase Reaction. PBR Example 1: Polymath Solution
  A + 2B → C
- Gas Phase Reaction. PBR Example 2: Analytical Solution
  A + B → C + D
  
  Lecture 9
  
  TODAY’S LECTURE
  
  Membrane Reactors: Used for Thermodynamically Limited Reactions
  
  Balances in Terms of Molar Flow Rates
  - Block 1: Mole Balances
    - Balance Equation on Every Species
  - Block 2: Rate Laws
    - Relative Rates
    - Transport Laws
  - Block 3: Stoichiometry
  - Block 4: Combine
  Multiple Reactions: Selectivety and Yield
  
  Lecture 10
  
  TODAY’S LECTURE
  
  Definition of Selectivety
  
  Instantaneous SD/U = rD/rU
  
  Overall = FD/FU
  
  Semibatch Reactors
  
  Lecture 11
  
  TODAY’S LECTURE
  - Determining the Rate Law from Experimental Data
    - Integral Method
    - Graphical Method
    - Nonlinear Least Regression
  - Multiple Reactions
    - The Four Types
    - What’s New to Our Algorithm
    - Reactions in Series
  Lecture 12
  
  Lecture 13
  
  Lecture 14
  
  Lecture 15
  
  Lecture 16
  
  Lecture 17
  
  Lecture 18
  
  Lecture 19
  
  Lecture 20
  
  Lecture 21
  
  Lecture 22
  
  Lecture 23
  
  Lecture 24
  
  Lecture 25
  
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