Milli-channel with metal foams under an applied gas-liquid periodic flow: External mass transfer performance and pressure drop

摘要

Overall external mass transfer and pressure drop performance are addressed for a square 2 mm width channel filled with metal foams as catalyst supports for gas-liquid-solid reactions under an applied pulsing regime. Overall mass transfer coefficients are determined for various foam morphologies and flow conditions by performing alpha-methylstyrene catalytic hydrogenation over a layer of wash-coated Pd/Al2O3. Values ranging from 0.25 to 1.9 s(-1) obtained. A theoretical model and correlations are derived to explain the observed results and agree well with the numerous experimental points. Required energy inputs are estimated by evaluating pressure drops. A predictive correlation is also proposed, as well as a comparison with other correlations from the literature. Finally, the performance of this reactor is compared with other macro- and milli-scale technologies. It has been concluded that foams in confined channels allow mass transfer rates to be increased by up to 50% in comparison with empty channels (monoliths) while maintaining very low energy inputs. (C) 2015 Published by Elsevier B.V.