1. The following kinetic data on the reaction A→R are obtained in an experimental packed
bed reactor using various amounts of catalyst and a fixed feed rate FAO= 10 kg-mol/hr.
W, kg cat
XA
1
0.12
2
0.20
3
0.27
4
0.33
5
0.37
6
0.41
7
0.44
a.) Find the reaction rate at 40% conversion.
b.) In designing a large packed bed reactor with feed rate FAO = 400 kmol/hr how
much catalyst would be needed for 40% conversion.
c.) How much catalyst would be needed in part (b) if the reactor employed a very
large recycle of product stream.
2. The second order reaction A→R is studied in a recycle reactor with very large recycle
ratio, and the following data are recorded:
Void volume of reactor:
1 liter
Weight of catalyst used:
3 gm
Feed to the reactor:
CAO = 2 mol/liter
vo = 1 liter/hr
Exit stream conditions:
CA.out = 0.5 mol/liter
(a) Find the rate constant for this reaction (give units).
(b) How much catalyst is needed in a packed bed reactor for 80%
conversion of 1000 liter/hr of feed of concentration CAO = 1 mol/liter.
No recycle.
(c) Repeat part (b) if the reactor is packed with 1 part catalyst to 4 parts
inert solid. This addition of inert helps maintain isothermal conditions
and eliminate hot spots.
Note: Assume isothermal conditions throughout.
3. Determine the order of reaction and the weight of catalyst needed for 35% conversion of
A to R for a feed of 2000 mol/hr of pure A at 117oC and 3.2 atm. For this reaction the
stoichiometry is A→R and the kinetic data are given in Example 2; also assume plug
flow in the packed bed reactor.
Note: compare answer with examples 2 and 4. The difference in values found is due to
ignoring the expansion, εA in treating this system.
4. Kinetic experiments on the solid catalyzed reaction A→3R are conducted at 8 atm and
700oC in a basket type mixed reactor 960 cm3 in volume and containing 1 gm of catalyst
of diameter dp = 3 mm. Feed consisting of pure A is introduced at various rates into the
reactor and the partial pressure of A in the exit stream is measured for each feed rate. The
results are as follows:
Feed rate, liters/hr
100
22
4
1
0.6
PA,out/OA,in
0.8
0.5
0.2
0.1
0.05
Find a rate equation to represent the rate of reaction on catalyst of this size.
5. At 700oC the rate of decomposition, A→3R, on a specific catalyst of given size is found
to be
1 dN A 
liter 
 C A
 rA  
 10
W dt
 hr.gm cat 
See previous problem for the data leading to this equation.) A pilot plant is to be built.
This is to be a tubular packed bed 2 cm ID using 25% of these active catalyst pellets
evenly mixed with 75% inert pellets to insure isothermal operations. For 400 mol/hr feed
consisting of 50% inert gas at 8 atm and 700oC what must be the length of reactor so that
PA,out/OA,in = 0.111.
Data: Catalyst and inert pellets are porous, of diameter dp = 3 mm, particle density ps= 2
gm/cm3. Bulk voidage of packed bed = 50%.
6. The solid-catalyzed decomposition of gaseous A proceeds as follows:
 rA  kC A 2
A→R
A tubular pilot plant reactor packed with 2 liters of catalyst is fed 2 m3/hr of pure A at
300 oC and 20 atm. Conversion of reactant is 65%.
In a larger plant it is desired to treat 100 m3/hr of feed gases at 40 atm and 300oC
containing 60% A and 40% diluents to obtain 85% conversion of A. Find the internal
volume of the reactor required.