Investigation of periodic operation of a trickle-bed reactor

Gas and liquid loadings of a co-current downflow trickle-bed reactor were separately modulated employing alpha -methyl styrene (AMS) hydrogenation on Pd/Al(2)O(3) to determine if the hydrogenation rate could be increased. Modulating the liquid flow rate resulted in a large increase in the AMS conversion rate. The explanation of the improvement in rate appears to be that modulation caused a transition from the trickling to the foaming-pulsing hydrodynamic regimes. The foam created in the latter regime persisted in the trickling portion of the cycle. Modulation of the gas loading was not effective probably because a regime transition did not occur. (C) 2001 Published by Elsevier Science Ltd. All rights reserved.