Environmental Engineering Reference
In-Depth Information
6.3
For the elementary reaction A
R, the conversion of A in 30 min is 0.5 in a
batch reactor. How long will it take before a conversion of 0.8 is achieved?
!
6.4
The elementary reaction A
!
R is carried out in a CSTR. What is the conversion?
Data
Total inlet mole flow
min
− 1
with 75% A and 25% inerts
Initial concentration of A c
A0
= 2 mol
φ
n
0
= 40 mol
L
−1
Volume of the reactor V = 500 L
Temperature in the reactor T = 400 K
Activation energy E
a
= 10,000 cal
mol
−1
andArrhenius constant k
0
=3×10
4
min
−1
6.5
The reaction A
!
R carried out in the liquid phase in a CSTR has a kinetic
L
−1
, and the
equilibrium conversion is
X
Ae
= 0.667. The reactor is working with a conversion
at the outlet
X
A
= 0.333. How should the feed rate be adjusted to obtain a
conversion of
X
A
= 0.5?
6.6
A chemical plant accidentally discharges a pollutant A into a river. Fortunately,
A degrades in time. Calculate how far from the plant the concentration of the
pollutant has decreased by 90%. What is the best reactor model for this problem?
What is the kinetic order for this reaction?
Data
Reaction rate coefficient k = 0.0008 mol
0.5
L
− 1
,c
R0
= 0 mol
expression(
-
R
A
)=
r
=k
1
c
A
−
k
2
c
R
.c
A0
= 1 mol
m
1.5
min
−1
s
−1
Cross section of the river
S
= 300 m
2
Concentration of A in the plant c
A0
= 0.02 mol
φ
V
= 200 m
3
River flow
m
−3
R
A
=kc
A
with k = 0.35 min
−1
mol
(1−n)
L
(n−1)
is
6.7
The reaction A
!
b
B+
c
C+
−
L
−1
obtaining a conversion
carried out in a tubular reactor with c
A0
= 1 mol
of
0.70.
An analysis of the residence time distribution, using the same flow and a
pulse injection of tracer gives
≈
t (min)
0
3
6
9
12
15
18
21
24
27
30
33
36
c
A
(molL
−1
)
0
0.1
3
6
8
9
6
5
4
2
1
0.2
0
What is the order of the reaction?
PROJECT
P6.1
Download and install the free software Reactor Lab (English), available at
http://www.simzlab.com/. Simulate the different reactors introduced in this
chapter for different conditions and orders of reaction. You can also use this
software to validate the scripts written by yourself, for instance, in Matlab.
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