Modeling of Cone-Shaped Pellets for Catalytic Reactors

Modeling of cone-shaped catalytic pellets was performed for irreversible first order reaction by finite element method. Calculations were also made assuming core-shell cone-shaped pellets with inert cores or hollow cone-shaped catalysts immersed in an infinitely large medium. Parameters affecting effectiveness factors (eta) such as Thiele modulus (phi) and cone-angle (beta) were studied to compare the results from conventional spherical or cylindrical pellets. An increase of eta could be predicted as beta increased from cone-shaped pellets. Hollow cone-shaped pellets were also assumed for CSTR to confirm the enhanced performance of the reactor by a larger hollow core for large phi. As a demonstrative application, cone-shaped pellets with insulated bottoms were considered for analysis of nano-cone arrays by calculating eta of the nano-patterns. Assuming pseudo-steady state approximation, unsteady behaviors of reactors containing cone-shaped pellets were predicted for batch and fixed bed reactors by solving reaction-diffusion equations assuming pseudo-steady state approximation. A coated wall reactor with nano-cone arrays could be modeled for the prediction of steady-state concentration in the reaction system. In addition to phi, beta and the number density of nano-cones on the substrate were found to be important factors affecting the performance of the coated wall reactor.