MONOLITH FROTH REACTOR - DEVELOPMENT OF A NOVEL 3-PHASE CATALYTIC-SYSTEM

The monolith froth reactor, involving two-phase flow and a monolith ca talyst, is developed. The flow within monolith channels, consisting of trains of gas bubbles and liquid slugs, is produced by forming a two- phase froth in a chamber immediately below the bottom of the monolith. The froth then flows upward into the monolith channels through pressu re forces, which differs from previous methods since it may be carried out for a commercial-scale reactor. Because the liquid film which dev elops between the gas phase and the surface of the catalyst is extreme ly thin, two-phase flow within a monolith can provide reaction rates w hich are near their intrinsic values. Catalytic oxidation of aqueous p henol over copper oxide supported on gamma Al2O3 is used as a model re action for investigating reactor performance. Generation of a froth is confirmed by visual inspection; the average bubble size is approximat ely that predicted by a force balance. The effect of externally contro llable process variables (liquid and gas flow rates, temperature, and pressure) on the rate of phenol oxidation was investigated Reaction ra te increases with temperature or pressure increase and decreases with gas flow rate increase, achieving a maximum with respect to liquid flo w rate. The activation energy calculated from the apparent reaction ra te measured in the monolith froth reactor is similar to that of intrin sic value, suggesting minimal mass-transfer limitations.