Experimental study of the effect of bubbles, drops and particles on the product distribution for a mixing sensitive, parallel-consecutive reaction system

For stirred multiphase reactors the effect of a dispersed (gas, liquid or solid) phase on the product distribution for a mixing sensitive reaction was tested. Turbulence modification due to the presence of dispersed-phase particles has been reported frequently in literature, but the extent of the effect in a stirred multiphase reactor was not clear. In this work the well-known mixing sensitive diazo-coupling reaction system was selected to investigate the influence of the changes in the turbulent kinetic energy spectrum on the product distribution. This reaction system was found to be suitable to study the influence of a dispersed (gas, liquid or solid) phase. The Engulfment model could describe the single-phase experiments and describes reasonably well the multiphase experiments when the effective dispersion properties are implemented. For the liquid-liquid dispersions effects of de-localization of the reaction zone were encountered, due to Naphthol extraction by the dispersed phase. The Engulfment model was extended to incorporate mass transfer and the first experimental and simulation results are promising. Additional, experimental and theoretical, research studying the combined effects of the mass transfer rate and the mixing rate for the liquid-liquid dispersions is highly desired. (C) 1999 Elsevier Science Ltd. All rights reserved.