Consider a first order reaction taking place on the surface of a catalyst with cylindrical pores. The relevant equation is
with the following boundary conditions:
at , ,
at , ,
Here is the pore length and is the surface concentration of species . The second boundary condition specifies that there is no flux of material through the interior end of the cylindrical catalyst pores. The concentration of reactant within a pore is given by , where is the Thiele modulus and .
This Demonstration plots the dimensionless concentration versus the dimensionless distance within the pores for user-set values of the Thiele modulus. It also gives the value of the effectiveness factor , where is the average concentration of species in the catalyst pores.