Exercise 7.9: A hollow-cylinder catalyst pellet in a fixed-bed reactor
Estimate the mass of catalyst required in an isothermal fixed-bed reactor for
the second-order reaction.
$k_1$
A \rightarrow B
r = k_1c_A^2
k_1 = 1.21 \times 10^5 cm^3/mol\cdot s
The feed is pure A at a molar flowrate of 15 mol/s, the total pressure is 3.0 atm
and the temperature is 550 K. The reactor achieves 90% conversion of A. The
catalyst is a hollow cylinder with an outer diameter of 1.3 cm, an inner diame-
ter of 0.5 cm, and a length of 0.7 cm. The pellet density $\rho_p = 0.73 g/cm^3$ and
the bed density $\rho_B = 0.58 g/cm^3$. The effective diffusivity of A is 0.008 $cm^2/s$
and may be assumed constant. You may assume the bulk and pellet surface
concentrations are equal.
