1.
A second order irreversible gas solid catalytic reaction 2A ? R is carried out
isothermally in a packed bed reactor of height 3 m and diameter 0.3 m. The packed
bed reactor can be treated as a CSTR. The reactor is filled with porous, 50 mm
diameter spherical catalyst pellets to give a bed voidage of 46%. In two trial runs,
at the same temperature, the following data were obtained:
Run
Volumetrical
Inlet concentration
Exit concentration
flowrate
of A
of A
(m³gas/s)
(kmol/m³gas)
(kmol/m³gas)
1
0.0143
0.025
0.0060
2
0.0360
0.025
0.0088
(a) Show that external mass transfer does not present a significant resistance
under these reactor conditions.
(b) Determine the effectiveness factor and determine the reaction rate constant
per unit area of catalyst surface.
Data:
Specific surface area
2.0 x 10? m²cat-surf/kgcat
Pellet density
1.2 x 10³ kg/m³cat
Effective diffusivity of A in catalyst pellet
8.0 x 10?? m³gas/(mcats)
For a nth order GS catalytic reaction with sphere catalysts, $\phi = \frac{R}{3} \sqrt{\frac{(n+1)k_{cat}C_{A}^{n}}{2D_{e}}}$
