This slide completely describes you about the stuff include in it and also everything about chemical engineeringThis slide completely describes you about the stuff include in it and also everything about chemical engineering. Fluid Mechanics. Thermodynamics. Mass Transfer Chemical Engineering. Energy Engineering, Mass Transfer 2, Heat Transfer,

1. 1

2. 22
CHE - 338
Chemical Reaction
Engineering I

3. Chemical Reaction Engineering I
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.
Reactor
Raw
Materia
l
Product

4. Chemical Reaction Engineering
4
Mole Balance Rate Laws Stoichiometry
These topics build upon one another.

5. CRE Algorithm
5
Rate Laws
Stoichiometry
Isothermal Design
Heat Effects

6. 6
Mole Balance Rate Laws
Be careful not to cut corners on any of the
CRE building blocks while learning this
material!

7. 7
Mole Balance
Rate Laws
Stoichiometry
Isothermal Design
Heat Effects
Otherwise, your Algorithm becomes unstable.

8. Reaction Rate
A + B R
8

9. 9
Types of Chemical Reactions
Multiple Reaction:
A R
Single
Reaction
A R S
Series
A
R
S
Parallel
A R
A S
Competitive
Side
by
side

10. 10
Types of Chemical Reactions
A + B R
R +
B
S
Side
by
side
A + B R
H2 + Br2 2HB
r

11. 11
Types of Chemical Reactions
A *R S
Nonchan
Reaction
A *R +
A
*T +S
S
Initiation
Propagation
TerminationChain
Reaction

12. Molecularity
 No. of colliding molecular entities that
are involved in a single reaction step
A + B C
 Uni/bi/termolecular reaction
12

13. Order of Reaction
aA + bB C
http://www.chemguide.co.uk/physical/basicrates/orders.html
13

14. Order of Reaction
 In chemical kinetics, the order of
reaction with respect to a given substance
(such as reactant, catalyst or product) is
defined as the index, or exponent, to which
its concentration term in the rate
equation is raised.
r = [A]x [B]y
 [A], [B], are concentrations,
 x for substance A & y for substance B, the
reaction orders/ partial reaction orders).
 Overall reaction order is
 x + y + .... 14

15. Representation of an Elementary
Reaction
2A 2R
A R
k1
-rA = rR = k1C2
A
k1
-rA = rR = k1CA
15

16. 16

17. 17

18. 18

19. 19

20. 20

21. 21

22. 22

23. 23

24. 24

25. 25

26. 26

27. 27

28. Representation of an Elementary
Reaction
B +2D 3T
k1
-rB = kBCBC2
D
-rD = kDCBC2
D rT = kTCBC2
D
-rB = -(1/2)rD = (1/3)rT
kB = (1/2)kD = (1/3)kT
28

29. Representation of a non
Elementary Reaction
29
N2 + 3H2 2NH3

30. Ideal Reactors
30
Batch Reactor
Uniform Composition
in reactor
Composition changes
with time

31. Ideal Reactors – Steady state
31
Plug Flow Reactor
Fluid passes through the reactor with no
mixing of earlier and later entering fluid,
and with no overtaking.
it is as if the fluid moved in single file
through the reactor.

32. Ideal Reactors – Steady state
32
Mixed Flow
•Uniformly mixed
•Same composition, in reactor and at

33. 33
Rate-Temperature Dependency
ri = f1 (temp). f2(comp)
k = koe-E/RT
ln k/ko = lne-E/RT
k1
k2
T1
T2
Arrhenius law

34. 34
Rate-Temperature Dependency
1/T
k
ln k α -E/RT
Low E
High E
k1
k2
T1T2
463K 376K
2000K 1000K
1000K
87K

35. Activation Energy and
Temperature Dependency
 From Arrhenius' law a plot of In k vs 1/T gives
a straight line, with large slope for large E and
small slope for small E.
 Reactions with high activation energies are
very temperature-sensitive; reactions with low
activation energies are relatively temperature-
insensitive.
 Any given reaction is much more
temperature-sensitive at a low temperature
than at a high temperature.
 From the Arrhenius law, the value of the
frequency factor k, does not affect the
temperature sensitivity.
35

36. Engr. Muhammad Sajid, UOG 36

37. 37
Problems

38. 38

39. Engr. Muhammad Sajid, UOG 39
Year
No. of
Days T 1/T 1/Tx10^(3) ln(1/day)
1976 87 22 295.15
0.00338
8 3.39
-
4.46591
1977 8523.4 296.55
0.00337
2 3.37
-
4.44265
1982 7426.3 299.45
0.00333
9 3.34
-
4.30407
1984 7824.3 297.45
0.00336
2 3.36
-
4.35671
1985 9021.1 294.25
0.00339
8 3.40
-
4.49981
-

40. 40
-4.55
-4.5
-4.45
-4.4
-4.35
-4.3
-4.25
3.33 3.34 3.35 3.36 3.37 3.38 3.39 3.40 3.41
ln(Rate)=ln(1/days)
1/T
Series1
Linear (Series1)
Slope = -E/R
- E = slope x R

41. 41