Steady‐state drop‐size distributions in high holup fraction dispersion systems

Abstract

AbstractMacroscopic phenomena in suspension polymerization reactors are extremely complex, and breakage and coalescene of polymerizing monomer droplets are not well understood, especially for high dispersed‐phase volume fractions. Depending on the agitation, concentration and type of surface‐active agent, the droplet size can exhibit a U experiementally and theoretically as the balance between breakage and coalescence rates of monomer drops. Both processes are related to the drop surface energy, which is proportional to the interfacial tension and its variation with time. In this study, the most comprehensive models describing breakage and coalescene processes in a dispersion system were incorporated into a generalized numerical algorithm to predict the steady‐state drop‐size distributinos in a high holdup (50%) liquid‐liquid distributions in high holdup dispersion systems, experiments were carried out with a model system of 50% n‐butyl chloride in water in the presence of a surface‐active agent, poly(vinyl alcohol), at different concentrations and agitation rates. The theoretical model can predict reasonably well the drop‐size distribution for all experimental investigation elucidates the relationships between the changing structure of PVA molecules at the monomer/water interface and their effects on breakage and coalescence frequencies at different agitation times and rates.