CRE

1. Chemical Reaction
Engineering
 Introduction and basic concepts.
 Chapter no 1 and 2
Dr. Muhammad Shahbaz
Subject Code: Ch.E-325
Cr.hrs: (3-1) 4

2. Lecturer objective
Introduction of chemical reaction engineering
Basic Concepts of reaction and reactor design
Why Chemical reaction engineering

3. Recommended books
Element of chemical Reaction Engineering
by H.Scot Fogler (3rd or fourth edition )
Chemical reaction Engineering by
Octave Levenspiel (3rd edition )
An Introduction to Engineering kinetics and
Reactor Design by Charles G.Hill

4. Introduction:
 Chemical Reaction Engineering (CRE) is the field
that studies the rates and mechanisms of chemical
reactions and the design of the reactors in which they
take place.
 Chemical reaction engineering is at the heart of
every chemical process. It separates the chemical
engineer from other engineers.
Industries that Draw Heavily on Chemical Reaction
Engineering (CRE) are:
CPI (Chemical Process Industries), Etmad, Aner flex,
Dow, DuPont, Amoco, Chevron , Alpha Laval, Descon,

5. Typical chemical reaction
RAW
MATERIAL
REACTOR
Undesirable Bi products
Separator Separator
Lab Scale Industrial Scale
Product

6. Why Reaction Engineering
Raw material conversion to final
product passes many steps
 Physical pre treatment
 Chemical treatment
 Physical final treatment
Physical treatment studied in unit operation like separation,
crushing, drying, cooling etc purification
Chemical treatment studied in unit process which involve
reaction these reaction take place in unit which called reactor.
Designing and controlling of that reaction deals by reaction
engineering and it is core step of production of product.

7. Reactor design and its parameters
Designing of reactor involve many
things
Economics in which
 Cost of reactor
 Product treatment cost
It is not routine matter of life, it
required knowledge and experiences
of various areas like
Thermodynamics, chemical kinetics,
heat transfer, mass transfer, fluid
mechanics,

8. Classification of reaction
Homogeneous reaction: A reaction in which reactant and product are in one
phase
Heterogeneous reaction: A reaction which involve more than one phase in
presence place. In which mostly catalytic reaction involved
Chemical reaction classified in many ways but in CRE this is most common

9. Chemical Identity
• Chemical identity A name that will uniquely identify a chemical.
This can be a name based on nomenclature systems of the
International Union of Pure and Applied Chemistry (IUPAC) or
the Chemical Abstracts Service (CAS), or a technical name. H2,
CO, CO2, Al2O3
• The identity of a chemical species is determined by the kind,
number, and configuration of that species’ atoms.
A chemical species is said to have
reacted when it has lost its chemical
identity.
When Chemical reaction happen

10. Chemical change
A chemical species is said to have reacted when it has lost its
chemical identity.
1. Combination
2. Decomposition
3. Single replacement reaction
Zn + HCl ZnCl2 + H2
CH3CH3 H2 + H2C
N2 +O2 2NO
AgNO3 + NaCl AgCl2 + NaNO3
4. Double replacement reaction

11. Reaction Rate
 The reaction rate is the rate at which a
species loses its chemical identity per unit
volume.
 The rate of a reaction (mol/dm3/s) can be
expressed as either
the rate of Disappearance: -rA
or as
the rate of Formation (Generation): rA
rA = the rate of formation of species A per unit volume
-rA = the rate of a disappearance of species A per unit volume
rB = the rate of formation of species B per unit volume
Consider the isomerization AB

12. Reaction Rate
EXAMPLE: AB
If Species B is being formed at a rate of 0.2 moles per
decimeter cubed per second, ie,
rB = 0.2 mole/dm3/s
rB = 0.2 mole/dm3/s
Then A is disappearing at the same rate: -rA= 0.2 mole/dm3/s
rB = 0.2 mole/dm3/s
Then A is disappearing at the same rate: -rA= 0.2 mole/dm3/s
The rate of formation (generation of A) is rA= -0.2 mole/dm3/s