fogler chapter 4 notes
TRANSCRIPT
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b
4 ALGORITHM FOR ISOTHERMAL R EACTOR DESIGN
Topics
Part 1 Mole Balances in Terms of Conversion
1 Algorithm for Isothermal Reactor Design2 ApplicationsExamples of CRE Algorithm3 Reversible Reactions
4 ODE (Polymath) Solutions to CRE Problems5 General Guidelines for California Problems6 PBR with Pressure Drop 7 Engineering Analysis
Part 2 Measures Other Than Conversion
1 Measures Other Than Conversion2 Membrane Reactors 3 Semibatch Reactors
Part 1 Mole Balances in Terms of Conversion
1 Algorithm for Isothermal Reactor Design top
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 2
French Menu Analogy
41 The reaction (2A+B--gtC) carried out in a CSTR PFR and a Batch Reactor
42 Labratory Experiment
43 Semilog plot to find reaction rate constant
to a closed ended PFRCSTR example
CHEMKIN Reactor Models
Example The elementary liquid phase reaction
is carried out isothermally in a CSTR Pure A enters at a volumetric flow rate of 25 dm3 s and at a concentration of 02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 3
moldm3
What CSTR volume is necessary to achieve a 90 conversion when k = 10 dm 3 (mols)
Mole Balance
Rate Law
Stoichiometry liquid phase (v = vo)
Combine
Evaluate at X = 09
V = 1125 dm3
Space Time
Here are some links to example problems You could also use these problems as self tests
CSTR Type 1 Home Problem
CSTR Type 2 Home Problem
CSTR Type 3 Home Problem
Critical Thinking Questions for CSTR
The following movies were made by the students of Professor Alan Lanes chemical reaction engineering class at theUniversity of Alabama Tuscaloosa
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 4
2 ApplicationsExamples of the CRE Algorithm top
Gas Phase Elementary Reaction Additional Information
only A fed P0 = 82 atm
T0 = 500 K CA0 = 02 moldm3
k = 05 dm3 mol-s vo = 25 dm3 s
Solve for X = 09
Applying the algorithm to the above reaction occurring in a Batch CSTR and PFR
Batch CSTR PFR
Mole Balance
Rate Law
StoichiometryGas V = V0
(eg constant volumesteel container)
Gas T =T0 P =P0 Gas T = T0 P = P0
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 5
Per Mole of A Per Mole of A
Combine
Integrate
Evaluate
For X = 09 V = 6806 dm3 V = 907 dm3
Visual Encyclopedia of Reaction Engineering Equipment
44 Gas Phase Reaction Example
CSTR and PFR Example
41 Calculate V for a Zero-Order Reaction
3 Reversible Reactions top
To determine the conversion or reactor volume for reversible reactions one must first calculate the maximum conversionthat can be achieved at the isothermal reaction temperature which is the equilibrium conversion (See Example 3-8 in thetext for additional coverage of equilibrium conversion in isothermal reactor design)
Equilibrium Conversion Xe
From Appendix C
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 6
45 Calculate Equilibrium Conversion (Xe) for a Constant Volume System
Example Determine Xe for a PFR with no pressure drop P = P0
Given that the system is gas phase and isothermal determine the reactor volume when X = 08 Xe
Reaction Additional Information
CA0 = 02 moldm3
KC = 100 dm3 mol
k = 2 dm3 mol-min
FA0 = 5 molmin
First calculate Xe
Xe = 089
X = 08Xe = 0711
One could then use Polymath to determine the volume of the PFR The corresponding Polymath program is
shown below
4 ODE (Polymath) Solutions to CRE Problems top
Algorithm Steps Polymath Equations
Mole Balance d(X)d(V) = -rAF A0
Rate Law rA = -k((CA2)-(CBKC))
Stoichiometry CA = (CA0(1-X))(1+epsX)
CB = (CA0X)(2(1+epsX))
Parameter Evaluation eps = -05 CA0 = 02 k = 2
FA0 = 5 KC = 100
Initial and Final Values X0 = 0 V0 = 0 Vf = 500
Polymath Screen Shots
Equations
Plot of X vs V
Results in Tabular Form
A volume of 94 dm
3
(rounding up from slightly more than 93 dm
3
) appears to be our answer
46 Batch Reactor With a Reversible Reaction
5 General Guidelines for California Problems top
Every state has an examination engineers must pass to become a registered professional engineer In the past there havetypically been six problems in a three hour segment of the California Professional Engineers Exam Consequently one shouldbe able to work each problem in 30 minutes or less Many of these problems involve an intermediate calculation todetermine the final answer
Some Hints
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 7
1 group unknown parametersvalues on the same side of the equation example
[unknowns] = [knowns]
2 look for a Case 1 and a Case 2 (usually two data points) to make intermediate calculations3 take ratios of Case 1 and Case 2 to cancel as many unknowns as possible
4 carry all symbols to the end of the manipulation before evaluating UNLESS THEY ARE ZERO
California Professional Engineers Registration Problem
47 Batch Reactor Optimization
6 PBR with Pressure Drop top
Note Pressure drop does NOT affect liquid phase reactions
Sample Question
Analyze the following second order gas phase reaction that occurs isothermally in a PBR
Mole Balance
Must use the differential form of the mole balance to separate variables
Rate Law
Second order in A and irreversible
Stoichiometry
Isothermal T = T0
Combine
Need to find (PP0) as a function of W (or V if you have a PFR)
Pressure Drop in Packed Bed Reactors
Ergun Equation
Variable Gas Density
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 8
let
Catalyst Weight
where
let
then
English-
Espanol-
Svenska-
We will use this form for multiple reactions
We will use this form for single reactions
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 2
French Menu Analogy
41 The reaction (2A+B--gtC) carried out in a CSTR PFR and a Batch Reactor
42 Labratory Experiment
43 Semilog plot to find reaction rate constant
to a closed ended PFRCSTR example
CHEMKIN Reactor Models
Example The elementary liquid phase reaction
is carried out isothermally in a CSTR Pure A enters at a volumetric flow rate of 25 dm3 s and at a concentration of 02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 3
moldm3
What CSTR volume is necessary to achieve a 90 conversion when k = 10 dm 3 (mols)
Mole Balance
Rate Law
Stoichiometry liquid phase (v = vo)
Combine
Evaluate at X = 09
V = 1125 dm3
Space Time
Here are some links to example problems You could also use these problems as self tests
CSTR Type 1 Home Problem
CSTR Type 2 Home Problem
CSTR Type 3 Home Problem
Critical Thinking Questions for CSTR
The following movies were made by the students of Professor Alan Lanes chemical reaction engineering class at theUniversity of Alabama Tuscaloosa
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 4
2 ApplicationsExamples of the CRE Algorithm top
Gas Phase Elementary Reaction Additional Information
only A fed P0 = 82 atm
T0 = 500 K CA0 = 02 moldm3
k = 05 dm3 mol-s vo = 25 dm3 s
Solve for X = 09
Applying the algorithm to the above reaction occurring in a Batch CSTR and PFR
Batch CSTR PFR
Mole Balance
Rate Law
StoichiometryGas V = V0
(eg constant volumesteel container)
Gas T =T0 P =P0 Gas T = T0 P = P0
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 5
Per Mole of A Per Mole of A
Combine
Integrate
Evaluate
For X = 09 V = 6806 dm3 V = 907 dm3
Visual Encyclopedia of Reaction Engineering Equipment
44 Gas Phase Reaction Example
CSTR and PFR Example
41 Calculate V for a Zero-Order Reaction
3 Reversible Reactions top
To determine the conversion or reactor volume for reversible reactions one must first calculate the maximum conversionthat can be achieved at the isothermal reaction temperature which is the equilibrium conversion (See Example 3-8 in thetext for additional coverage of equilibrium conversion in isothermal reactor design)
Equilibrium Conversion Xe
From Appendix C
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 6
45 Calculate Equilibrium Conversion (Xe) for a Constant Volume System
Example Determine Xe for a PFR with no pressure drop P = P0
Given that the system is gas phase and isothermal determine the reactor volume when X = 08 Xe
Reaction Additional Information
CA0 = 02 moldm3
KC = 100 dm3 mol
k = 2 dm3 mol-min
FA0 = 5 molmin
First calculate Xe
Xe = 089
X = 08Xe = 0711
One could then use Polymath to determine the volume of the PFR The corresponding Polymath program is
shown below
4 ODE (Polymath) Solutions to CRE Problems top
Algorithm Steps Polymath Equations
Mole Balance d(X)d(V) = -rAF A0
Rate Law rA = -k((CA2)-(CBKC))
Stoichiometry CA = (CA0(1-X))(1+epsX)
CB = (CA0X)(2(1+epsX))
Parameter Evaluation eps = -05 CA0 = 02 k = 2
FA0 = 5 KC = 100
Initial and Final Values X0 = 0 V0 = 0 Vf = 500
Polymath Screen Shots
Equations
Plot of X vs V
Results in Tabular Form
A volume of 94 dm
3
(rounding up from slightly more than 93 dm
3
) appears to be our answer
46 Batch Reactor With a Reversible Reaction
5 General Guidelines for California Problems top
Every state has an examination engineers must pass to become a registered professional engineer In the past there havetypically been six problems in a three hour segment of the California Professional Engineers Exam Consequently one shouldbe able to work each problem in 30 minutes or less Many of these problems involve an intermediate calculation todetermine the final answer
Some Hints
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 7
1 group unknown parametersvalues on the same side of the equation example
[unknowns] = [knowns]
2 look for a Case 1 and a Case 2 (usually two data points) to make intermediate calculations3 take ratios of Case 1 and Case 2 to cancel as many unknowns as possible
4 carry all symbols to the end of the manipulation before evaluating UNLESS THEY ARE ZERO
California Professional Engineers Registration Problem
47 Batch Reactor Optimization
6 PBR with Pressure Drop top
Note Pressure drop does NOT affect liquid phase reactions
Sample Question
Analyze the following second order gas phase reaction that occurs isothermally in a PBR
Mole Balance
Must use the differential form of the mole balance to separate variables
Rate Law
Second order in A and irreversible
Stoichiometry
Isothermal T = T0
Combine
Need to find (PP0) as a function of W (or V if you have a PFR)
Pressure Drop in Packed Bed Reactors
Ergun Equation
Variable Gas Density
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 8
let
Catalyst Weight
where
let
then
English-
Espanol-
Svenska-
We will use this form for multiple reactions
We will use this form for single reactions
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 3
moldm3
What CSTR volume is necessary to achieve a 90 conversion when k = 10 dm 3 (mols)
Mole Balance
Rate Law
Stoichiometry liquid phase (v = vo)
Combine
Evaluate at X = 09
V = 1125 dm3
Space Time
Here are some links to example problems You could also use these problems as self tests
CSTR Type 1 Home Problem
CSTR Type 2 Home Problem
CSTR Type 3 Home Problem
Critical Thinking Questions for CSTR
The following movies were made by the students of Professor Alan Lanes chemical reaction engineering class at theUniversity of Alabama Tuscaloosa
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 4
2 ApplicationsExamples of the CRE Algorithm top
Gas Phase Elementary Reaction Additional Information
only A fed P0 = 82 atm
T0 = 500 K CA0 = 02 moldm3
k = 05 dm3 mol-s vo = 25 dm3 s
Solve for X = 09
Applying the algorithm to the above reaction occurring in a Batch CSTR and PFR
Batch CSTR PFR
Mole Balance
Rate Law
StoichiometryGas V = V0
(eg constant volumesteel container)
Gas T =T0 P =P0 Gas T = T0 P = P0
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 5
Per Mole of A Per Mole of A
Combine
Integrate
Evaluate
For X = 09 V = 6806 dm3 V = 907 dm3
Visual Encyclopedia of Reaction Engineering Equipment
44 Gas Phase Reaction Example
CSTR and PFR Example
41 Calculate V for a Zero-Order Reaction
3 Reversible Reactions top
To determine the conversion or reactor volume for reversible reactions one must first calculate the maximum conversionthat can be achieved at the isothermal reaction temperature which is the equilibrium conversion (See Example 3-8 in thetext for additional coverage of equilibrium conversion in isothermal reactor design)
Equilibrium Conversion Xe
From Appendix C
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 6
45 Calculate Equilibrium Conversion (Xe) for a Constant Volume System
Example Determine Xe for a PFR with no pressure drop P = P0
Given that the system is gas phase and isothermal determine the reactor volume when X = 08 Xe
Reaction Additional Information
CA0 = 02 moldm3
KC = 100 dm3 mol
k = 2 dm3 mol-min
FA0 = 5 molmin
First calculate Xe
Xe = 089
X = 08Xe = 0711
One could then use Polymath to determine the volume of the PFR The corresponding Polymath program is
shown below
4 ODE (Polymath) Solutions to CRE Problems top
Algorithm Steps Polymath Equations
Mole Balance d(X)d(V) = -rAF A0
Rate Law rA = -k((CA2)-(CBKC))
Stoichiometry CA = (CA0(1-X))(1+epsX)
CB = (CA0X)(2(1+epsX))
Parameter Evaluation eps = -05 CA0 = 02 k = 2
FA0 = 5 KC = 100
Initial and Final Values X0 = 0 V0 = 0 Vf = 500
Polymath Screen Shots
Equations
Plot of X vs V
Results in Tabular Form
A volume of 94 dm
3
(rounding up from slightly more than 93 dm
3
) appears to be our answer
46 Batch Reactor With a Reversible Reaction
5 General Guidelines for California Problems top
Every state has an examination engineers must pass to become a registered professional engineer In the past there havetypically been six problems in a three hour segment of the California Professional Engineers Exam Consequently one shouldbe able to work each problem in 30 minutes or less Many of these problems involve an intermediate calculation todetermine the final answer
Some Hints
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 7
1 group unknown parametersvalues on the same side of the equation example
[unknowns] = [knowns]
2 look for a Case 1 and a Case 2 (usually two data points) to make intermediate calculations3 take ratios of Case 1 and Case 2 to cancel as many unknowns as possible
4 carry all symbols to the end of the manipulation before evaluating UNLESS THEY ARE ZERO
California Professional Engineers Registration Problem
47 Batch Reactor Optimization
6 PBR with Pressure Drop top
Note Pressure drop does NOT affect liquid phase reactions
Sample Question
Analyze the following second order gas phase reaction that occurs isothermally in a PBR
Mole Balance
Must use the differential form of the mole balance to separate variables
Rate Law
Second order in A and irreversible
Stoichiometry
Isothermal T = T0
Combine
Need to find (PP0) as a function of W (or V if you have a PFR)
Pressure Drop in Packed Bed Reactors
Ergun Equation
Variable Gas Density
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 8
let
Catalyst Weight
where
let
then
English-
Espanol-
Svenska-
We will use this form for multiple reactions
We will use this form for single reactions
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 4
2 ApplicationsExamples of the CRE Algorithm top
Gas Phase Elementary Reaction Additional Information
only A fed P0 = 82 atm
T0 = 500 K CA0 = 02 moldm3
k = 05 dm3 mol-s vo = 25 dm3 s
Solve for X = 09
Applying the algorithm to the above reaction occurring in a Batch CSTR and PFR
Batch CSTR PFR
Mole Balance
Rate Law
StoichiometryGas V = V0
(eg constant volumesteel container)
Gas T =T0 P =P0 Gas T = T0 P = P0
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 5
Per Mole of A Per Mole of A
Combine
Integrate
Evaluate
For X = 09 V = 6806 dm3 V = 907 dm3
Visual Encyclopedia of Reaction Engineering Equipment
44 Gas Phase Reaction Example
CSTR and PFR Example
41 Calculate V for a Zero-Order Reaction
3 Reversible Reactions top
To determine the conversion or reactor volume for reversible reactions one must first calculate the maximum conversionthat can be achieved at the isothermal reaction temperature which is the equilibrium conversion (See Example 3-8 in thetext for additional coverage of equilibrium conversion in isothermal reactor design)
Equilibrium Conversion Xe
From Appendix C
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 6
45 Calculate Equilibrium Conversion (Xe) for a Constant Volume System
Example Determine Xe for a PFR with no pressure drop P = P0
Given that the system is gas phase and isothermal determine the reactor volume when X = 08 Xe
Reaction Additional Information
CA0 = 02 moldm3
KC = 100 dm3 mol
k = 2 dm3 mol-min
FA0 = 5 molmin
First calculate Xe
Xe = 089
X = 08Xe = 0711
One could then use Polymath to determine the volume of the PFR The corresponding Polymath program is
shown below
4 ODE (Polymath) Solutions to CRE Problems top
Algorithm Steps Polymath Equations
Mole Balance d(X)d(V) = -rAF A0
Rate Law rA = -k((CA2)-(CBKC))
Stoichiometry CA = (CA0(1-X))(1+epsX)
CB = (CA0X)(2(1+epsX))
Parameter Evaluation eps = -05 CA0 = 02 k = 2
FA0 = 5 KC = 100
Initial and Final Values X0 = 0 V0 = 0 Vf = 500
Polymath Screen Shots
Equations
Plot of X vs V
Results in Tabular Form
A volume of 94 dm
3
(rounding up from slightly more than 93 dm
3
) appears to be our answer
46 Batch Reactor With a Reversible Reaction
5 General Guidelines for California Problems top
Every state has an examination engineers must pass to become a registered professional engineer In the past there havetypically been six problems in a three hour segment of the California Professional Engineers Exam Consequently one shouldbe able to work each problem in 30 minutes or less Many of these problems involve an intermediate calculation todetermine the final answer
Some Hints
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 7
1 group unknown parametersvalues on the same side of the equation example
[unknowns] = [knowns]
2 look for a Case 1 and a Case 2 (usually two data points) to make intermediate calculations3 take ratios of Case 1 and Case 2 to cancel as many unknowns as possible
4 carry all symbols to the end of the manipulation before evaluating UNLESS THEY ARE ZERO
California Professional Engineers Registration Problem
47 Batch Reactor Optimization
6 PBR with Pressure Drop top
Note Pressure drop does NOT affect liquid phase reactions
Sample Question
Analyze the following second order gas phase reaction that occurs isothermally in a PBR
Mole Balance
Must use the differential form of the mole balance to separate variables
Rate Law
Second order in A and irreversible
Stoichiometry
Isothermal T = T0
Combine
Need to find (PP0) as a function of W (or V if you have a PFR)
Pressure Drop in Packed Bed Reactors
Ergun Equation
Variable Gas Density
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 8
let
Catalyst Weight
where
let
then
English-
Espanol-
Svenska-
We will use this form for multiple reactions
We will use this form for single reactions
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 5
Per Mole of A Per Mole of A
Combine
Integrate
Evaluate
For X = 09 V = 6806 dm3 V = 907 dm3
Visual Encyclopedia of Reaction Engineering Equipment
44 Gas Phase Reaction Example
CSTR and PFR Example
41 Calculate V for a Zero-Order Reaction
3 Reversible Reactions top
To determine the conversion or reactor volume for reversible reactions one must first calculate the maximum conversionthat can be achieved at the isothermal reaction temperature which is the equilibrium conversion (See Example 3-8 in thetext for additional coverage of equilibrium conversion in isothermal reactor design)
Equilibrium Conversion Xe
From Appendix C
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 6
45 Calculate Equilibrium Conversion (Xe) for a Constant Volume System
Example Determine Xe for a PFR with no pressure drop P = P0
Given that the system is gas phase and isothermal determine the reactor volume when X = 08 Xe
Reaction Additional Information
CA0 = 02 moldm3
KC = 100 dm3 mol
k = 2 dm3 mol-min
FA0 = 5 molmin
First calculate Xe
Xe = 089
X = 08Xe = 0711
One could then use Polymath to determine the volume of the PFR The corresponding Polymath program is
shown below
4 ODE (Polymath) Solutions to CRE Problems top
Algorithm Steps Polymath Equations
Mole Balance d(X)d(V) = -rAF A0
Rate Law rA = -k((CA2)-(CBKC))
Stoichiometry CA = (CA0(1-X))(1+epsX)
CB = (CA0X)(2(1+epsX))
Parameter Evaluation eps = -05 CA0 = 02 k = 2
FA0 = 5 KC = 100
Initial and Final Values X0 = 0 V0 = 0 Vf = 500
Polymath Screen Shots
Equations
Plot of X vs V
Results in Tabular Form
A volume of 94 dm
3
(rounding up from slightly more than 93 dm
3
) appears to be our answer
46 Batch Reactor With a Reversible Reaction
5 General Guidelines for California Problems top
Every state has an examination engineers must pass to become a registered professional engineer In the past there havetypically been six problems in a three hour segment of the California Professional Engineers Exam Consequently one shouldbe able to work each problem in 30 minutes or less Many of these problems involve an intermediate calculation todetermine the final answer
Some Hints
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 7
1 group unknown parametersvalues on the same side of the equation example
[unknowns] = [knowns]
2 look for a Case 1 and a Case 2 (usually two data points) to make intermediate calculations3 take ratios of Case 1 and Case 2 to cancel as many unknowns as possible
4 carry all symbols to the end of the manipulation before evaluating UNLESS THEY ARE ZERO
California Professional Engineers Registration Problem
47 Batch Reactor Optimization
6 PBR with Pressure Drop top
Note Pressure drop does NOT affect liquid phase reactions
Sample Question
Analyze the following second order gas phase reaction that occurs isothermally in a PBR
Mole Balance
Must use the differential form of the mole balance to separate variables
Rate Law
Second order in A and irreversible
Stoichiometry
Isothermal T = T0
Combine
Need to find (PP0) as a function of W (or V if you have a PFR)
Pressure Drop in Packed Bed Reactors
Ergun Equation
Variable Gas Density
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 8
let
Catalyst Weight
where
let
then
English-
Espanol-
Svenska-
We will use this form for multiple reactions
We will use this form for single reactions
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 6
45 Calculate Equilibrium Conversion (Xe) for a Constant Volume System
Example Determine Xe for a PFR with no pressure drop P = P0
Given that the system is gas phase and isothermal determine the reactor volume when X = 08 Xe
Reaction Additional Information
CA0 = 02 moldm3
KC = 100 dm3 mol
k = 2 dm3 mol-min
FA0 = 5 molmin
First calculate Xe
Xe = 089
X = 08Xe = 0711
One could then use Polymath to determine the volume of the PFR The corresponding Polymath program is
shown below
4 ODE (Polymath) Solutions to CRE Problems top
Algorithm Steps Polymath Equations
Mole Balance d(X)d(V) = -rAF A0
Rate Law rA = -k((CA2)-(CBKC))
Stoichiometry CA = (CA0(1-X))(1+epsX)
CB = (CA0X)(2(1+epsX))
Parameter Evaluation eps = -05 CA0 = 02 k = 2
FA0 = 5 KC = 100
Initial and Final Values X0 = 0 V0 = 0 Vf = 500
Polymath Screen Shots
Equations
Plot of X vs V
Results in Tabular Form
A volume of 94 dm
3
(rounding up from slightly more than 93 dm
3
) appears to be our answer
46 Batch Reactor With a Reversible Reaction
5 General Guidelines for California Problems top
Every state has an examination engineers must pass to become a registered professional engineer In the past there havetypically been six problems in a three hour segment of the California Professional Engineers Exam Consequently one shouldbe able to work each problem in 30 minutes or less Many of these problems involve an intermediate calculation todetermine the final answer
Some Hints
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 7
1 group unknown parametersvalues on the same side of the equation example
[unknowns] = [knowns]
2 look for a Case 1 and a Case 2 (usually two data points) to make intermediate calculations3 take ratios of Case 1 and Case 2 to cancel as many unknowns as possible
4 carry all symbols to the end of the manipulation before evaluating UNLESS THEY ARE ZERO
California Professional Engineers Registration Problem
47 Batch Reactor Optimization
6 PBR with Pressure Drop top
Note Pressure drop does NOT affect liquid phase reactions
Sample Question
Analyze the following second order gas phase reaction that occurs isothermally in a PBR
Mole Balance
Must use the differential form of the mole balance to separate variables
Rate Law
Second order in A and irreversible
Stoichiometry
Isothermal T = T0
Combine
Need to find (PP0) as a function of W (or V if you have a PFR)
Pressure Drop in Packed Bed Reactors
Ergun Equation
Variable Gas Density
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 8
let
Catalyst Weight
where
let
then
English-
Espanol-
Svenska-
We will use this form for multiple reactions
We will use this form for single reactions
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 7
1 group unknown parametersvalues on the same side of the equation example
[unknowns] = [knowns]
2 look for a Case 1 and a Case 2 (usually two data points) to make intermediate calculations3 take ratios of Case 1 and Case 2 to cancel as many unknowns as possible
4 carry all symbols to the end of the manipulation before evaluating UNLESS THEY ARE ZERO
California Professional Engineers Registration Problem
47 Batch Reactor Optimization
6 PBR with Pressure Drop top
Note Pressure drop does NOT affect liquid phase reactions
Sample Question
Analyze the following second order gas phase reaction that occurs isothermally in a PBR
Mole Balance
Must use the differential form of the mole balance to separate variables
Rate Law
Second order in A and irreversible
Stoichiometry
Isothermal T = T0
Combine
Need to find (PP0) as a function of W (or V if you have a PFR)
Pressure Drop in Packed Bed Reactors
Ergun Equation
Variable Gas Density
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 8
let
Catalyst Weight
where
let
then
English-
Espanol-
Svenska-
We will use this form for multiple reactions
We will use this form for single reactions
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 8
let
Catalyst Weight
where
let
then
English-
Espanol-
Svenska-
We will use this form for multiple reactions
We will use this form for single reactions
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 919
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 9
IsothermalOperation
recall that
notice that
The two expressions are coupled ordinary differential equations We can solve them simultaneously usingan ODE solver such as Polymath For the special case of isothermal operation and epsilon = 0 we canobtain an analytical solution
Polymath will combine the mole balance rate law and stoichiometry
Analytical Solution [e] PFR with
CAUTION Never use this form if
Combine
Solve
Could now solve for X given W or for W given X
For gas phase reactions as the pressure drop increases the concentration decreases resulting in a decreased rate of reaction hence a lower conversion when compared to a reactor without a pressure drop
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1019
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 10
42 Pressure Drop in a Packed Bed Reactor
43 Pressure and Reaction Orders
48 Formation of Ethyl Acetate
Here are some links to example problems dealing with packed bed reactors You could also use these problems as self tests
PBR Type 1 Home Problem
PBR Type 2 Home Problem
PBR Type 3 Home Problem
POLYMATH
Consider the following gas phase reaction carried out isothermally in a packed bed reactor Pure A is fed at a rate of 25
moless and with and α = 00002 kg-1
2A B
Mole Balance
Rate Law
Elementary
Stoichiometry
Gas with T = T0
A B2
POLYMATH will combine everything - You do not need the combine step Thank you POLYMATH
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1119
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 1
Profiles
44 What Four Things are Wrong with this Solution
Optimum Paritcle Diameter
Laminar Flow Fix P0 ρ0
ρ0 = P0(MW)RT0
ρ0P0simP02
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1219
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 12
Increasing the particle diameter descreases the pressure drop and increases the rate and conversion
However there is a competing effect The specific reaction rate decreases as the particle size increases therefore so deosthe conversion
k sim 1Dp
DP1 gt DP2
k1 gt k2
Higher k higher conversion
The larger the particle the more time it takes the reactant to get in and out of the catalyst particle For a given catalyst
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1319
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 13
weight there is a greater external surgace area for smaller particles than larger particles Therefore there are more entryways into the catalyst particle
In CD-ROM chapter 12 we will learn that effectiveness factor decreases as the particle size increases
7 Engineering Analysis - Critical Thinking and Creative Thinking top
We want to learn how the various parameters (particle diameter porosity etc) affect the pressure drop and henceconversion We need to know how to respond to What if questions such as
If we double the particle size decrease the porosity by a factor of 3 and double the pipe size what will happen
to D P and X
(See Critical Thinking in Preface page xx eg Questions the probe consenquences)
To answer these questions we need to see how a varies with these parameters
Turbulent Flow
Compare Case 1 and Case 2
For example Case 1 might be our current situation and Case 2 might be the parameters we want to change to
For constant mass flow through the system = constant
Laminar Flow
45 Effect of Reducing Particle Size on Conversion in a PBR
Here are more links to example problems dealing with packed bed reactors Again you could also use these problems asself tests
PBR Type 5 Home Problem
PBR Type 7 Home Problem
PBR Type 8 Home Problem
Part 2 Measures Other Than Conversion
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1419
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 14
1 Measures Other Than Conversion top
Uses
A Membrane reactorsB Multiple reaction
Liquids Use concentrations IE CA
1 For the elementary liquid phase reaction carried out in a CSTR where V vo CAo k and Kc are given and the feed
is pure A the combined mole balance rate laws and stoichiometry are
There are two equations two unknowns CA and CB
Gases Use Molar Flow Rates IE FI
2 If the above reaction carried out in the gas phase in a PFR where V voCAok and Kc are given and the feed ispure A the combined mole balance rate laws and stoichiometry yield for isothermal operation (T=To) and no pressuredrop (P=0) are
Use Polymath to plot FA and FB down the length of the reactor
49 Stoichiometry for Measures Other than Conversion
46 Gas Phase PFR
47 Liquid Phase CSTR
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1519
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 15
Use Creative and then Critical Thinking
48 What Four Things are Wrong With this solution
Microreactors
For isothermal microreactors we use the same equations as a PFR as long as the flow is not laminar If the flow is laminarwe must use the techniques discussed in chapter 13 See example 48 of the text
University of Washington Transport Effects in Microreactors site
Institut fr Mikrotechnik Mainz GmbH
2 Membrane Reactors top
Membrane reactors can be used to achieve conversions greater than the original equilibrium value These higher conversionsare the result of Le Chateliers Principle you can remove one of the reaction products and drive the reaction to the right Toaccomplish this a membrane that is permeable to that reaction product but is impermeable to all other species is placedaround the reacting mixture
Example The following reaction is to be carried out isothermally in a membrane reactor with no pressure drop Themembrane is permeable to Product C but it is impermeable to all other species
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1619
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 16
For membrane reactors we cannot use conversion We have to work in terms of the molar flow rates F A FB FC
Polymath Program
Mole Balances
Rate Laws
StoichiometryIsothermal no pressure drop
Combine Polymath will combine for you-- Thanks Polymathyou rock
Parameters
Solve Polymath
49 What four things are wrong with this membrane reactor solution
Here are links to example problems dealing with membrane reactors You could also use these problems as self tests
Membrane Type 4 Home Problem (Heterogeneous)
Membrane Type 4 Home Problem (Homogeneous)
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1719
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 17
Membrane Type 7 Home Problem
Membrane Type 8 Home Problem
3 Semibatch Reactors p 190 top
Semibatch reactors can be very effective in maximizing selectivity in liquid phase reactions
to Selectivity
The reactant that starts in the reactor is always the limiting reactant
Three Forms of the Mole Balance Applied to Semibatch Reactors
1 Molar Basis
2 Concentration Basis
3 Conversion
For constant molar feed
For constant density
Use the algorithm to solve the remainder of the problem
Example Elementary Irreversible Reaction
Consider the following irreversible elementary reaction
-rA = kCACB
The combined mole balance rate law and stoichiometry may be written in terms of number of moles conversion andorconcentration
Conversion Concentration Number of Moles
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1819
292016 Chapter 4 Summary Notes
httpwwwumichedu~elementsfoglerampgurmenhtmlcourselectur esfourindexhtmtest1b 18
Polymath Equations
Conversion Concentration Moles
d(X)d(t) = -raVNao d(Ca)d(t) = ra - (Cavo)V d(Na)d(t) = raV
ra = -kCaCb d(Cb)d(t) = rb + ((Cbo-Cb)vo)V d(Nb)d(t) = rbV + Fbo
Ca = Nao(1 - X)V ra = -kCaCb ra = -kCaCb
Cb = (Nbi + Fbot - NaoX)V rb = ra rb = ra
V = Vo + vot V = Vo + vot V = Vo + vot
Vo = 100 Vo = 100 Vo = 100
vo = 2 vo = 2 vo = 2
Nao = 100 Fbo = 5 Fbo = 5
Fbo = 5 Nao = 100 Ca = NaV
Nbi = 0 Cbo = Fbovo Cb = NbV
k = 01 k = 001 k = 001
Na = CaV
X = (Nao-Na)Nao
Polymath Screenshots
C onv er sion C onc entr ation
Polymath Equations Polymath Equations
SummaryTable Summary Table
Conversion vsTime Conversion vsTime
Concentration vsTime Concentration vsTime
Volume vsTime Volume vsTime
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan
8182019 Fogler chapter 4 notes
httpslidepdfcomreaderfullfogler-chapter-4-notes 1919
292016 Chapter 4 Summary Notes
Critical Thinking Questions
Equilibrium Conversion in Semibatch Reactors with Reversible Reactions
Consider the following reversible reaction
Everything is the same as for the irreversible case except for the rate law
Where
At equilibrium -rA=0 then
410 Semibatch A rarr B Acid Catalyzed
See Also
Web Module on Reactive Distillation
Web Module on Wetlands
You Rate Some Wetlands Critical Thinking Questions
Object Assessment of Chapter 4
All chapter references are for the 4th Edition of the text Elements of Chemical Reaction Engineering
top
Fogler amp Gurmencopy 2007 University of Michigan