48
ChE 229 Advanced Chemical Reaction Engineering I
ChE 229Advanced Chemical
Reaction Engineering I
Course Description: Reactor design for homogeneous reactions.
Prerequisite: ChE 125(Chemical Reaction Engineering I)
Course Credit: 3 units (3 h lec)
Course Outcomes
Course Outline
Meeting Topic1 Introduction and course overview
2-3 Stoichiometry and mass balance 1. Stoichiometric coefficient2. Reaction rates and production rates3. Stoichiometry of multiple reactions
4 Kinetics of elementary reactions 1. Review of chemical kinetics calculations2. Review of pseudo-steady state hypothesis
5-6 Reaction mechanism and kinetics
FIRST LONG EXAMINATION
Course OutlineMeeting Topic
7-9 Design of ideal reactors1. Batch reactors2. Semi-batch reactors3. Continuously stirred tank reactors (CSTRs)4. Plug flow reactors (PFRs)
10-12 Ideal reactor design with energy balance1. Batch reactors2. Semi-batch reactors3. Continuously stirred tank reactors (CSTRs)
a. Multiple steady states4. Plug flow reactors (PFRs)5. Non-isothermal and adiabatic design calculations
13 Unsteady-state energy balance
SECOND LONG EXAMINATION
Course OutlineMeeting Topic
14 Mixing in reactors1. Tank reactors2. Flow reactors
15 Design of non-ideal reactors1. Residence time distribution (RTD)
a. Exit distribution function, E(t)b. Cumulative RTD function, F(t)
2. Tracersa. Pulse injectionb. Step injection
3. Statistical treatment
16 Parameter estimation
THIRD LONG EXAMINATION
References
(2016) Pearson Education, Inc. IN.
(1970) McGraw-Hill, Inc. NY.
(2002) Nob Hill Publishing. WI.
(2011) John Wiley & Sons, Inc. NJ.
(2001) Gulf Publishing Company. TX.
Learning Methods
✓ Lecture
✓ Classwork
✓ Article review
✓ Self-study
Evaluation Criteria
Requirement Credit
Long Exams (3) 75%
Homework 25%
TOTAL 100%
GRADE 5.0 3.0 2.75 2.5 2.25 2.0 1.75 1.5 1.25 1.0
AVE 0-59 60-63 64-67 68-71 72-75 76-79 80-83 84-87 88-91 92-100
No grade of 4.0 or INC will be given in this course.
Evaluation Criteria
Class Policies
Corrections will only be entertained up to 5 working days upon the return of exam
papers. There shall be no makeup for any missed long exam submission regardless of
the reason.
Class Policies
Submission of long exam answers beyond the specified deadline shall be given a 25-point deduction for every one-hour period of late submission (i.e., if the deadline is 5:00 pm, a
student shall receive a 25-point deduction if s/he submits within the period of 5:01-6:00 pm, 50
points if within the 6:01-7:00 pm period, and so on).
Class Policies
Students shall be assigned to submit a computer-aided homework on a specific topic on chemical
reactor design, which must be passed by uploading in the appropriate Google Drive shared folder by
the date of submission deadline. There shall be no makeup for any missed homework submission
regardless of the reason.
Class Policies
University rules on class attendance shall be observed.
Class Policies
All students are expected to observe proper classroom etiquette and follow the University rules on student discipline as written in the 2012 Code of
Student Conduct of UP Diliman.
https://osu.up.edu.ph/wp-content/uploads/2015/09/2012-Code-of-Student-Conduct.pdf
Class Policies
The instructor reserves the right to modify the schedule or any of the class policies without prior
notice to the students when deemed necessary.
Consultation
Mon
Tue & Thur
830 – 1130 am
1000 – 1130 am400 – 600 pm
Rm 302 Chem Engg
Bldg C
Consultation beyond the specified schedules may bedone by setting up appointments.
E-mail: [email protected]
Contact No: +63-2-8981-8500 local 3212/3113
Overview
What is chemical reaction engineering?
Chemical reaction engineering (CRE) is that engineeringactivity concerned with the exploitation of
on a . Its goal is thesuccessful and of chemical reactors,and probably more than any other activity, it setschemical engineering apart as a distinct branch of theengineering profession.
- O. Levenspiel (2004)
20
relates input to output
- how materials flow- how materials
contact each other- how early/late the
mixing occurs- how materials
aggregate
- how fast reactions will happen
- what materials will leave the reactor
- how heat and mass transfer affect the chemical reaction
General mole balance
VjR0
j0
Q
c
1
j1
Q
c
= − +
rate of rate of rate of rate ofaccumulation inflow of outflow of generation of
of component j component j component j component j
Example: 2 22NO + O 2NO
− − + =1 2 32A A 2A 0
− − =
1
2
3
A2 1 2 A 0
A
+ − =2 22NO O 2NO 0
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
− −
− − = − −
1
2
3
4
5
6
AA
0 1 0 1 1 1 0A
1 1 1 1 0 0 0A
1 0 1 0 1 1 0AA
→ =A 0
Reading assignment
Review the following:
- Matrix algebra
- Reaction mechanisms (PSSH)
- First-order linear differential equations
- Kinetics of nth order reactions
- Conversion efficiency and sizing of differentreactors (batch, semi-batch, CSTR, PFR)
Reaction Stoichiometry
: the determination of the proportionsin which chemical elements combine or are producedand the weight relations in any chemical reaction.
• mass conservation in chemical reactions
• linearly independent reactions
• ,
= =
= → = j
n n
j j j Aj 1 j 1
A 0 M 0
Example: + 2 22NO O 2NO
− − + =1 2 32A A 2A 0
= ==
= − == −2 2
2 2 3 21
O NONO
A O A NOA NO
1 2 2
Example: + 2 22NO O 2NO
− − + =1 2 32A A 2A 0
− − =
1
2
3
A2 1 2 A 0
A→ =A 0
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
= = =
= = =
1 2 2 3
4 2 5 6 2
A H A H A OH
A H O A CO A CO
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
− − + =
− + + − =
− − + =
2 4 5 6
1 2 3 4
1 3 5 6
A A A A 0
A A A A 0
A A A A 0
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
− −
− − = − −
1
2
3
4
5
6
AA
0 1 0 1 1 1 0A
1 1 1 1 0 0 0A
1 0 1 0 1 1 0AA
→ =A 0
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
+ +2 2 2H O CO CO H
−
− − − −
= − − ⎯⎯⎯⎯⎯→ − −
− − − −
row 1 row 2
0 1 0 1 1 1 1 0 1 0 1 11 1 1 1 0 0 1 1 1 1 0 0
1 0 1 0 1 1 1 0 1 0 1 1
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
−
− −
= − − ⎯⎯⎯⎯⎯→ − −
− − − −
row 1 row 3
1 0 1 0 1 1 0 0 0 0 0 01 1 1 1 0 0 1 1 1 1 0 0
1 0 1 0 1 1 1 0 1 0 1 1
+ +2 2 2H O CO CO H
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
− −
= − − ⎯⎯⎯⎯⎯→ − −
− −
row 1 row 3
0 0 0 0 0 0 1 0 1 0 1 11 1 1 1 0 0 1 1 1 1 0 0
1 0 1 0 1 1 0 0 0 0 0 0
+ +2 2 2H O CO CO H
=rank 2
Linearly independent reactions
• Rank of the stoichiometric matrix
• There are more columns (number of species) than rows (number of independent reactions)
Consider the oxidation of methane in which theobserved species are
It is desired to determine the largest number oflinearly independent valid chemical reactionsamong these species.
= T
2 2 4 2 2A CO H O CH CO H O
Formation reactions: +
+
+
+
2 2
2 2 2
2 4
2
C O CO2H O 2H OC 2H CH2C O 2CO
= T
2 2 4 2 2A CO H O CH CO H O C
= T
1 2 3 4 5 6 7A A A A A A A A
Formation reactions:
− − − − =
− −
− −
1 0 0 0 0 1 10 2 0 0 2 1 00 0 1 0 2 0 10 0 0 2 0 1 2
=rank 4
+
+
+
+
2 2
2 2 2
2 4
2
C O CO2H O 2H OC 2H CH2C O 2CO
Reaction rateDefined as the number of times a reaction eventtakes place per time per volume
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
=
r
V t = reaction extent
1r
2r
3r
Production rateDefined as the rate at which a species is produceddue to the chemical reactions taking place
Example: + +
+ +
+ +
2 2 2
2 2
2
H O CO CO HH O H H OHOH CO CO H
= +2CO 1 3R r r
= −OH 2 3R r r
1r
2r
3r
ExampleConsider the steam cracking of ethane
( )
( )
( )
( )
→ +
→ +
→ +
+ →
2 6 2 4 2
2 6 2 2 2
2 4 2 2 2
2 6 2 4
1 C H C H H
2 C H C H 2H
3 C H C H H
4 C H H 2CH
( )
( )
( )
( )
→ +
→ +
→ +
+ → +
2 6 6 6 2
2 6 2
2 2 2
2 2
5 3C H C H 6H
6 C H 2C 3H
7 C H 2C H
8 C H O CO H
= + + − + + + +2H 1 2 3 4 5 6 7 8R r 2r r r r 3r r r
= − − − − −
= −
= + + − + + + +
= + −
=
=
= + −
= −
=
2 6
2 4
2
2 2
4
6 6
2
C H 1 2 4 5 6
C H 1 3
H 1 2 3 4 5 6 7 8
C H 2 3 7
CH 4
C H 5
C 6 7 8
H O 8
CO 8
R r r r 3r r
R r r
R r 2r r r 6r 3r r r
R r r r
R 2r
R r
R 2r 2r r
R r
R r
− − − − − − − − = = − −
2 6
2 4
2
2 2
4
6 6
2
C H
1C H
2H
3C H
4CH
5
C H6
C 7
H O 8
CO
R1 1 0 1 3 1 0 0
rR 1 0 1 0 0 0 0 0rR 1 2 1 1 6 3 1 1r
R 0 1 1 0 0 0 1 0r
R 0 0 0 2 0 0 0 0Rr
0 0 0 0 1 0 0 0R r0 0 0 0 0 2 2 1R r0 0 0 0 0 0 0 1R r0 0 0 0 0 0 0 1R
r
( )
( )
( )
( )
( )
( )
( )
( )
( )
( )
+
+
+
+ +
+ +
+ +
+ +
+
+
+
4 2 2
4 3
4 2 2 6
2 4 2 4 2
4 3 2
4 3 2 5 2
4 3 2
4 2 5
4 2
2 2
1 SiH SiH H
2 SiH SiH H
3 SiH SiH Si H
4 Si H H SiH SiH
5 SiH H SiH H
6 SiH SiH Si H H
7 SiH SiH SiH SiH
8 SiH SiH Si H
9 SiH Si 2SiH
10 Si H SiH
( )
( )
( )
( )
( )
( )
( )
( )
( )
( )
+
+
+ +
+
+
+
+
+
+
+
2 2 3
2 2 2
2 3 2 2 2
2 2 2 2 4
2 2 4 2 6
2 3
2 2 2 2
2 2 3 2 5
2 2 2 3
3 2
11 SiH SiH Si H
12 SiH Si Si H
13 SiH Si Si H Si
14 H Si H Si H
15 H Si H Si H
16 H SiH SiH
17 H Si Si H
18 H Si H Si H
19 Si H H Si H
20 Si Si 2Si
1. The CVD reactions are a simplified version of 120reactions that were originally postulated for thisreaction network.
2. Combustion chemistry: several hundred reactions.
3. Polymerizations and long-chain-producing reactions:thousands of species and associated reactions.
4. The stoichiometry of these complex problems isintractable if we do not develop a systematic,automated procedure.
HomeworkConsider the following set of chemical reactions
a. How many of thesereactions are linearlyindependent?
b. If all the reactionrates are equal to 1mol/s, calculate theproduction rates ofeach species.
+
+
+
+ + +
+
+
2 5 2 4 2
2 5 2 3
2 3 2 5
2 3 2 2
2 5 2
2 2 2 4
2N O 2N O O
N O NO NO
NO NO N O
NO NO NO O NO
NO N O 3NO
NO NO N O
