Power, gas dispersion and homogenisation characteristics of Scaba SRGT and rushton turbine impellers.

TLDR

The 6‑blade SRGT’s higher hold‑up matches its increased power input, suggesting it could provide a proportionally higher kLa. The study proposes that gassed reactors equipped with adequately powered motors can retrofit the SRGT to achieve markedly improved performance. In low‑to‑moderate viscosity fluids, the 6‑blade SRGT uses 0.8–1× the ungassed power, tolerates up to three times more gas before flooding, and achieves homogenisation comparable to a standard Rushton turbine at the same gassed power, whereas the gassed Rushton turbine draws only 0.4–0.5× the ungassed power.

Abstract

The Scaba SRGT agitator with six blades when gassed draws between 1 and 0.8 times the ungassed power in fluids of low and moderate viscosity respectively. Under similar conditions, the gassed Rushton turbine draws 0.5 to 0.4 times the ungassed power. In addition, some three times more gas can be handled at the same ungassed power by this SRGT before flooding occurs. The increased hold-up achieved by the 6SRGT is commensurate with the increased power input and it is argued that the potentially extra power available should be able to give a similarly enhanced kLa. The 6SRGT agitator also gives an equivalent homogenisation performance to a standard Rushton turbine agitator of the same size at the same gassed power input. When gassed reactors are fitted with motors of sufficient power to be capable of running at full speed when ungassed, this agitator offers simple retrofitting possibilities potentially leading to considerably enhanced performance.