Effect of the catalyst wettability on the performance of a trickle-bed reactor for ethanol oxidation as a case study

A comparative study on the performance of a trickle-bed reactor packed eith er with hydrophilic, hydrophobic catalyst particles or mixtures of hydropho bic catalyst-hydrophilic inert support in different mass proportions is car ried out. Ethanol oxidation at moderate temperature and atmospheric pressur e is selected as a model reaction. Experimental runs employing pure oxygen, relatively high ethanol concentrations and different liquid and gas flow r ates are performed for each type of bed. A remarkable improvement in the re actor performance is found when the hydrophobic catalyst is employed, wheth er the bed is completely hydrophobic or diluted with hydrophilic support. A n increase in ethanol conversion of even 100% is achieved for certain condi tions. Experimental results are examined through a comprehensive model that rakes into account the influence of particles' wettability on the reactor behavior. It allows us to understand the role of particles' wettability and , consequently, to explain the large improvement in the performance of the trickle-bed reactor when hydrophobic catalyst is used. The model properly d escribes the effect of bed wetting characteristics on the reactor performan ce in a wide range of operating conditions. (C) 1999 Elsevier Science Ltd. All rights reserved.