Evaluation of the use of ceramic foams as catalyst supports for reverse-flow combustors

The performance of a silicon carbide foam supported palladium catalyst (Pd/beta-SiC) in a reverse flow reactor for the abatement of methane in diluted streams (2700-5400 ppm) has been studied in this article. The limits of stable operation for this configuration have been experimentally established, being narrower than the corresponding to particulated and honeycomb monolith beds because of the lower thermal inertial of foamed beds. A heterogeneous one-dimensional model has been developed (including the use of specific correlations for mass transfer and dispersive terms) and experimentally validated for predicting the behaviour of these reactors. Finally, the numerical model has been used for simulating reverse-flow reactors equipped with different catalyst shapes (e.g. Raschig rings, honeycomb monoliths and foams) of equivalent geometry. Results for different superficial velocities (0.25-1.5 m/s) are compared in terms of transport properties and performance, concluding that honeycomb monolithic beds are the most appropriate configuration for these devices. (C) 2013 Elsevier B.V. All rights reserved.