ASAP

8. A countercurrent moving bed reactor with downflow of solids and upflow of gas is to be designed for the reaction A(g)+B(s)C(s)+D(g). The reactor is to be operated at constant pressure and temperature with a feed concentration of A of 5mol/m3. The reactor dlameter is 1m with a gas flow rate of 3m3/s.Specially prepared 0.02m dlameter pellets of B are fed from the top of the reactor at a rate of 0.5kg/s. The pellets are very reactive and very porous layer of C is formed during reaction and effective diffusivity through the product layer is 110 m2/s. Neglect external diffusion resistance and the change in size of pellets with reaction. The value of reaction rate constant, k is 1mm/s. Total solid fraction in the bed is 0.5 . The pellet density is 5000kg/m3. Since the molecular weights (=120) of B and C are not very different, the mass flow rate of solld may be assumed to be constant over the reactor length. Correlate the conversion with the reactor length