Assessment of mixing performance and power consumption of a novel polymerization reactor system

A melt-phase polymerization reactor with the novel geometry of two helical solid-tube impellers rotating within a tank, consisting of two intersecting cylinders, was designed and constructed. In order to evaluate the performa nce of the system, mixing times and power consumption were measured using a viscous Newtonian model fluid (glucose syrup) in place of the polymer melt . The mixing regime was laminar in all runs, The mixing time at various imp eller speeds was estimated by injection of a tracer dye (crystal violet), f ollowed by fluid sampling and visible spectrophotometric analysis. A dimens ionless mixing time of k(m) = 104 +/- 36 was obtained. The power draw requi red to move each impeller through the fluid at various impeller speeds was measured, and a power constant of k(p) = 1156 +/- 70 was obtained. The syst em appeared to outperform the conventional single helical ribbon impeller i n terms of mixing time, but was less energy-efficient, as indicated by the larger power constant. The power constant value lies between values previou sly reported in the literature for conventional helical impellers and value s reported for other types of polymerization reactors with different geomet ries.