V. Tukac et al., The effect of oxygen transport and hydrodynamics on the phenol oxidation in a trickle-bed reactor, CHEM LISTY, 94(7), 2000, pp. 449-452
Hydrodynamics, uniform wetting of the catalyst surface and transport of rea
ction components show a strong influence on the overall performance of a tr
ickle-bed reactor. The aim of the paper was finding limits for predominant
effects of the catalyst wetting, oxygen transport and surface reaction in a
catalytic wet oxidation of aqueous solutions of phenol, which is a typical
bactericidal pollutant, undesirable in the environment. A three phase high
-pressure laboratory tubular reactor 18 mm in diameter with catalyst bed le
ngth 200 mm was run at 130-170 degrees C, pressures 2-7 MPa and space veloc
ity 1-20 h(-1). Oxidation activities of two catalyst types, CuO on a silica
te carrier (Cherox(R) 46-00) and extruded active carbon (Chemviron(R)) were
compared. At a comparable loading, active carbon showed a higher catalytic
activity. For elimination of the effect of nonuniform distribution of liqu
id and achieving a perfect wetting of the catalyst surface with liquid, the
catalyst beds diluted with 1-mm glass spheres were also tested. However, u
nder conditions, when the resulting oxidation rate is limited by the transp
ort of a key component from the gas phase (oxygen), the uniform wetting of
the catalyst surface with the reaction mixture leads to a lower performance
of the oxidation reactor due to a lower interphase area caused by a higher
liquid hold-up.