Biomedical Engineering Reference
In-Depth Information
fractional yield concept is useful. When numerical methods are used, the complexity
would not however deter a solution with today's computers.)
5.44. Under ultraviolet radiation, reactant A of
C
A0
¼
10 kmol/m
3
in a liquid process stream
1m
3
/min) decomposes as follows:
(
Q
¼
=
m
3
$
min
r
1
¼ 16C
0:
A
A
/
R
kmol
=
m
3
$
min
A
/
S
r
2
¼ 12C
A
kmol
=
m
3
$
min
r
3
¼ 0:5 C
2
A
2A
/
T
kmol
We wish to design a reactor setup to maximize the production R.
(a) What type of reactor or reactor scheme is to be selected?
(b) Calculate the fraction of feed transformed into the desired product R as well as the
volume of the reactor needed.
(c) Repeat a. and b. if the desired product is S instead.
5.45. The gas-phase decomposing reaction
; r ¼ kC
A
is to be carried out adiabatically in a flow reactor. The feed consists of pure A at
a temperature of 298 K and a pressure of 1 bar. The feed rate is 0.1 mol/s. Neglect
the pressure drop in the reactor.
(a) Calculate the operating temperature and conversion from a CSTR of volume 2 m
3
.
(b) Calculate the volume of a PFR for a conversion of 0.99. Comment on your
findings.
(c) Recalculate the volume of the PFR for a conversion of 0.99, but the feed to the reactor
is preheated to 500 K.
The additional data are:
k
A
/
B
þ
C
10
11
exp
s
1
E
R
T
E
R
¼
¼
18000
K;
D
H
R
¼
60 kJ/mol-A;
;
C
PA
¼
120
J
=ð
mol
$
K
Þ
;
C
PB
¼
80
J
=ð
mol
$
K
Þ
;
C
PC
¼
40
J
=ð
mol
$
K
Þ
5.46. Consider the elementary reaction: A
þ
R
/
2 R with a rate constant equal
$
s
1
. We wish to process 1.5 L/s of a feed containing 10 mol/L A to the
highest conversion possible in the reactor system consisting of four 150-L CSTR's
connected as you wish and any feed arrangement.
(a) Sketch your recommended design and feed arrangement.
(b) Determine the final conversion.
(c) Comment on the reactor start-up conditions.
5.47. We wish to convert A to R in a plug flow reactor by the aqueous decomposition
reaction:
0.001 L
$
mol
1
A
/
R
þ
U
;
r
1
¼ k
1
C
A
1.2 m
3
/(mol
$
min). We realized that A can also be dimerized to S:
A
where
k
1
¼
r
2
¼ k
2
C
2
A
þ
A
/
S
;
40 mol/m
3
.
with
k
2
¼
0.8/min. The aqueous feed contains A by
C
A0
¼
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