Kinetics experiments were performed with several different sizes of spherical cata$-$

lyst pellets. In all experiments, the bulk concentration of A was fixed at $0\mathrm{.}025mo\frac{l}{L},$

with A fed through the catalyst bed at $350C.$ The reaction is suspected to be first order,

of the form $A$ products. Data are shown in the table, below:

a$)$ Determine the rate constant for the intrinsic reaction and the effective diffusivity based on

the $1mm$ and $20mm$ particles. State all assumptions.

b$)$ Determine the effectiveness factor and Thiele modulus for each particle.

Numerical answers:

$k_A=439s^{-1}$

$De=9\mathrm{.}13{10}^{-5}\frac{m^2}{s}$

$(1mm)=0\mathrm{.}96$

${}^{\text{'}}(1mm)=0\mathrm{.}365$