Page 546 - Elements of Chemical Reaction Engineering Ebook

51 6 Steady-State Nonisothermal Reactor Design Chap. 8
3FA0 enters the reactor. Plot the conversion as a function ,of the entering
temperature. Is there a maximum? If so, why? If not, why not?
(f) Ask another question or suggest another calculation that can be made for
this problem.

Additional information:
C,, = 1 mol/dm3 Ua = 5.0 kT/s. dm3/K
FA0 = 5 mol/s T, = 700 K
AHRx = - 231 -O.O12(T- 298) kJ/mol
C,, = 0.1222 kJ/mol. K
k = 1.48X 10” exp(-19,124/T) dm3/mol*s
To = 675 K
[Lundgard, Int. J. Chem Kinet., 16, 125 (1984).]
PS-lOB The irreversible endothermic vapor-phase reaction follows an elementary rate
law :

CH,COCH, -+ CH,CO + CH,
A-+B+C

and is carried out adiabatically in a 500-dm3 PFR. Species A is fed to the reac-
tor at a rate of 10 mol/min and a pressure of 2 atm. An inert stream is also fed
to the reactor at 2 atm. The entrance temperature of both streams is 1100 K.

Figure P8-10

(a) First derive an expression for CAol as a function of CAo and OI.
(b) Plot the exit conversion as a function of el.
(c) Is there a ratio of inerts to the entering molar flow rate of A (ie., 01
=
FIo/FAo) at which the conversion is at a maximum? Explain why there
“is” or “is not” a maximum.
(a) How would your answer change if the entering temperature were
increased or decreased by 200 K?
(e) What do you believe to be the point of this problem?
Additional information:

k = exp (34.34 - 34,222/T) dm3/mol * min CpI = 200 J/mol* K
(T in degrees Kelvin)
CPA = 170 J/mol * K CpB = 90 J/mol* K
C,, = 80 J/mol- K AH,, = 80,000 J/mol