May 12, 2015
KMU 308-21-22-23 MIDTERM 2
1- The acid catalyzed irreversible liquid phase reaction A
B is carried out
adiabatically in a CSTR. The reaction is second order in A. The feed, which is equal
molar in water (which contains the catalyst) and A, enters the reactor at a temperature
of 52˚C and a total volumetric flow rate of 10 dm3/min. The concentration of A
entering the reactor is 4 molar.
a) What is the reactor volume to achieve 80% conversion (30 points) ?
b) What conversion can be achieved in a 1000 dm3 CSTR? What is the exit temperature
(20 points)?
2. The first order liquid phase reaction AB (k=0.092 min-1) will be carried out in an
isothermal CSTR with the volumetric capacity of 1000 liters. At the beginning, the reactor is
empty and at this time it is started to pump the feed with the rate of 100 liter/min. to the reactor
and so the reaction is initiated. The feed contains only A (no B) with the concentration of
CAo(mole/dm3). Unfortunately the pump is out of order after operation of 4 min. and it takes 10
min to replace this pump with the new one with the capacity of 150 liter/min. During these
operations there is no outlet from the reactor up to filling to complete.
a. What will be the conversion when the reactor is filled up? (40 points)
b. What is the steady state conversion in this reactor ? (10 points).
General Information:
General macroscopic energy balance;
Q  W s  FA0   i C pi (T  T0 )  H R (T )( FA0 X ) 
E system
The energy balance for adiabatic CSTR, PFR, and Batch reactor is given by;
T  T0 
H R (T0 ) X
 C
i 1
 XC p