Page 247 - Elements of Chemical Reaction Engineering 3rd Edition

Chap. 4 Journal Critique Problems 21 9
Additional information:
Specific reaction rate = 0.05 s-1
Transport coefficient k, = 0.3 s-l
Equilibrium constant = K, = 0.5
Entering volumetric flow rate uo = 10 dm3/s
CA, = 0.2 moUdm3
P4-3lC (Merqbrme reactor) The first-order, reversible reaction
A t-’B+2C
is taking place in a membrane reactor. Pure A enters the reactor, and B dif-
fuses through the membrane. Unfortunately, some of the reactant A also dif-
fuses through the membrane.
(a) Plot the flow rates of A, B, and C down the reactor, as well as the flow
rates of A and B through the membrane.
(b) Compare the conversion profiles of a conventional PFR with those 00 an
IMRCF. What generalizations can you make?
(c) Would the conversion of A be greater or smaller if C were difusing out
instead of B?
(d) Discuss how your curves would change if the temperature were incre<ased
significantly or decreased significantly for an exothermic reaction and for
an endothermic reaction.
Additional information:
k = 10 min-1 FA0 = 100 moUmin
Kc == 0.01 moI2/dm6 uo = 100 dm3/rnin
kcA := 1 min-l V,,,,, = 20 dm3
km := 40 min-’
P4-32* Load the htemctive Computer Module QCM) from the CD-ROM. Run the module
and then record your perfommce number for the madule which indicates your snas-
tering of the mate&l. Your professor has the key to decode your performance number.
(a) ICM Mystery Theater Performance #
(b) ICM Tic Tac Performance #
JOURNAL CRITIQUE PROBLEMS

P4C-1 In the article describing the liquid reaction of isoprene and maleic anhydride under
pressure [AIChE J., 16(5), 766 (1970)1, the authors show the reaction rate tal be
greatly accelerated by the application of pressure. For an equimolar feed they alite
the second-oder wtion rate expression in terms of the mole fraction y:

and then show the effect of pressure on ky (s-l). Derive this expression from
first princaples and suggest a possible logical explanation for the increase in
the me specific reaction rate constant k (dm3/moi+s) with pressure that is
different from the authors’. Make a quick check to verify your challenge.
P4C-2 The reduction of NO by char was carried out in 8 fixed bed between 500 and
845°C [Znt. Chem. Eng., 20(2), 239, (1980)l. It was concluded that the reac-
tion is first-order with respect to the concentration of NO feed (300 to 1CH)o
ppm) over the temperature range studied. It was also found that activation
energy begins to increase at about 680°C. Is first-order the true reacuion
order? If tiVere were disCrepaneies in this ankle, what might be the reasolls for thm?