Axial dispersion of liquid in gas-liquid cocurrent downflow and upflow fixed-bed reactors with porous particles

The authors present the experimental investigation of the residence time distribution of the liquid in a gas-liquid downflow and upflow fixed-bed reactor with porous particles and air/Newtonian or non-Newtonian liquid systems. The influence of imposed gas phase distribution along the packing bed on the axial mixing of liquid was examined. A tracer injection technique was used and the dynamic responses were interpreted using the piston-dispersion-exchange model with Danckwerts' boundary conditions. The dynamic evolution of the tracer concentration in the particles was described in terms of diffusion phenomena. An imperfect pulse method was used to estimate the model parameters directly from the experimentally input nonideal response and output response.