Chemical Reaction Engineering
Jayant M. Modak
Department of Chemical Engineering
Indian Institute of Science, Bangalore
Indian Institute of Science
About Chemical Reaction Engineering and Engineer
! One feature that distinguishes the education
of Chemical Engineer from that of other
Engineer is an exposure to the basic
concepts of Chemical Reaction Engineering
Charles Hill, An Introduction to Chemical Engineering
Kinetics and Reactor Design
Indian Institute of Science
About Chemical Reaction Engineering and Engineer
! Chemical Reaction Engineering is that
engineering activity which is concerned with
the exploitations of Chemical Reactions on a
Commercial Scale
Octave Levenspiel, Chemical Reaction Engineering
Indian Institute of Science
About Chemical Reaction Engineering and Engineer
! Typical tasks of Chemical Engineer are
" Design of Chemical Processes
" Maintain and Operate a process
" Fix some perceived problems
" Increase capacity or selectivity at minimum cost
Lanny Schmidt, The Engineering of Chemical Reactions
Indian Institute of Science
Scope of Chemical Reaction Engineering
! petroleum refining, petrochemicals,
chemicals, and pharmaceuticals
! biotechnology, microelectronics, advanced
materials, and energy from non-fossil
resources
! environment, pollution prevention,
sustainable development
Indian Institute of Science
Chemical Reaction Engineering New frontiers
! New analytical instrumentation providing
quantitative information on species and
mechanisms
! New computational resources hardware
and software
! Multiscale approach
Indian Institute of Science
Top Global Players in 2008
Rank Company Sales
$ bn
1 BASF (Germany) 70.5
2 DOW (U.S.) 57.5
3 Ineos (UK) 36
4 LyondalBasell 38.4
5 ExxonMobile Chemicals (USA) 38.4
27 Reliance Industries (India) 12.6
Chemical & Engineering News, August 2009
Indian Institute of Science
Narrowing In
Chemical & Engineering News, July 2007
Indian Institute of Science
Chemical Industry Sectors
Category Typical Plant
(TPA)
Price ($/
kg)
E-Factor
(Kg/Kg)
Petroleum Refining 10
6
- 10
8
0.05 0.1
Commodity chemicals 10
4
- 10
6
0.05-1 1-3
Fine chemicals 10
2
- 10
4
1-5 2-10
Foods 0.5-25
Materials 0- ....
Pharmaceuticals 10
- 10
3
10 - ...... 10-100
Electronic chemicals, Environment, Neutraceuticals, Chiral and
Biopharmaceuticals,
Lanny Schmidt, The Engineering of Chemical Reactions
Indian Institute of Science
What do you we need to know about chemical processes?
Lanny Schmidt, The Engineering of Chemical Reactions
Chemistry is important
A + B - > C + D is not a real reaction
Example: Ammonia synthesis
N -- N + 3 H -- H ! 2 N -- H
3
Example: aspirin synthesis
Indian Institute of Science
What do you we need to know about chemical processes?
Single reaction in an ideal single phase isothermal
reactor is hardly encountered. Real reactors are
extremely complex with multiple reactions multiple
phases and intricate flow patterns
Example: Ethylene synthesis
C
2
H
6
" C
2
H
4
+ H
2
C
2
H
6
" C
2
H
2
+ H
2
3 C
2
H
6
" C
6
H
6
+ 6 H
2
C
2
H
6
" 2 C + 3 H
2
Indian Institute of Science
What do you we need to know about chemical processes?
Example: Ammonia synthesis
CH
4
+ H
2
O " CO + 3 H
2
N
2
+ 3 H
2
! 2 NH
3
Indian Institute of Science
What do you we need to know about chemical processes?
Reactions with simple kinetics are extremely rare.
Example: Ammonia synthesis
Indian Institute of Science
Most industrial processes are heterogeneous
Process Reaction Conditions Reactor Comments
Catalytic
naptha
reforming
Naptha (?) ! aromatics
Endothermic
350-4000 kPa
490-525 C
Pt-Al
2
O
3
G-S,
Fixed Bed Catalyst
deactivation
Regeneration
NO
x
Absorption
2 NO + O
2
! 2 NO
2
(G)
NO
2
(G) ! NO
2
(L)
2 NO
2
+ H
2
O ! HNO
2
+ HNO
3
(L)
1 Atm
25-30 C
G-L
Packed tower
Chemical
Vapor
Deposition
SiCl
4
+ H
2
! Si (S) + 4
HCl
10
-6
- 10
-3
atm
1000-1200 C
micron
thickness
G-S
Chamber
reactors
Uniformity
essential
Flow past
plate
Antibiotics
Production
Glucose ! Penicillin
Exothermic
1 atm, 30 C
microbial cells
G-L-C
Stirred tank
reactors
Living
Indian Institute of Science
Transport processes are important
Ammonia Reactor - 1500 t NH3/day,
100 m
3
volume, 250 t of catalyst.
Catalyst - Fe with K and Al
2
O
3
Indian Institute of Science
Industrial reactors have intricate flow patterns
A : The main flow (pale blue) first
flows along the pressure shell and
cools it.
B : In the first bed, both the
temperature and the concentration
increases.
C : The gas is cooled in the upper heat
exchanger and the third inlet gas
stream (dark blue) is added.
D : In the second bed, both the
temperature and the concentration
increases.
Indian Institute of Science
Summary - Chemical Reactor Analysis
R. Aris, Ind. & Eng. Chemistry, 56, p.22, 1964
Step 1 - Kinetics
Indian Institute of Science
Summary - Chemical Reactor Analysis
R. Aris, Ind. & Eng. Chemistry, 56, p.22, 1964
Step 2 Reactor design
Course outline
Indian Institute of Science
Topic
1. Review of undergraduate reaction engineering:
Stoichiometry, thermodynamics of reacting systems,
kinetics of elementary reactions, ideal reactors: CSTR/
PFR
2. Kinetics of complex reactions:
Reaction mechanism and kinetics, Chain, catalytic,
polymerization, biochemical reactions, Analysis of
reaction network, lumping analysis, Parameter
estimation
Course outline
Indian Institute of Science
Topic
3. Conservation equations for chemically reacting
mixtures
4. Heterogeneous reactions:
Mass transport with reaction, Catalytic and Non-catalytic
gas-solid reactions, Gas-liquid reactions
5. Chemical Reactor Design:
Transient and steady state analysis, Optimal design of
reactors, Multiphase reactors: fixed, fluidized, trickle bed,
slurry etc, Non-ideal continuous flow reactors
Course Textbooks/Reference
! Aris R., Elementary Chemical Reactor Analysis,
Prentice-Hall 1969.
! Foggler, H. S., Elements of Chemical Reaction
Engineering, Prentice Hall of India, 1994.
! Fromment G.F. and Bischoff K.B., Chemical
Reactor Analysis and Design, John Wiley 1994.
! Schimdt L., The Engineering of Chemical
Reactions, Oxford, 2005
Indian Institute of Science
