Solid-liquid contacting effectiveness in trickle bed reactors

Internal and external effective wetting of a porous catalyst in a trickle bed reactor was considered. Experimental tests were carried out based on the analysis of the response curves of the reactor to a step decrease of the tracer inlet concentration.The pore filling of the catalyst pellets was practically total even at very low liquid flow rates, probably due to capillarity.The external effective wetting was interpreted in terms of an apparent internal diffusivity (D_i)_app, determined on the basis of a model which assumes a total external wetting of the catalyst. The values of (D_i)_app increased with the liquid flow rate, tending to the actual internal diffusivity D_i determined in a full reactor. The found values of (D_i)_app/D_i were used to interpret the ratio of the apparent kinetic rate constant determined in a trickle reactor k_app and that for a totally wetted catalyst k_v.The calculated values agree substantially with those proposed by Satterfield[3] from kinetic tests.