• Muddasar Habib

• Jamil Ahmed

• Mohammad Jaffar

• Unsia Habib

• Abdul Rehman Memon

• Nusruth Begum Mohabuth

• Taimur Ahmad Kaka Khel

• Farooq Khan Khalil

• Faisal Abbasi

• Muhammad Haris Nisar

Abstract

The pharmaceutical sector often uses non-standard impellers and stirred tank reactor (STR) geometries, compared to those in other chemical processes. Many such reactors are glass-lined to provide corrosion prevention and to avoid product contamination. Typically, these contain retreat curve impellers, which may have been modified to fit into a conical-based vessel, designed for ease of product discharge. These geometries are not covered by the standard correlations in the literature. This research work was carried out using a conical-based vessel with a diameter of 0.29 m. Power numbers have been obtained for a range of impeller clearances and baffling arrangements and correction factors have been proposed to account for the effect of the conical base and partial baffles. Liquid blending operations have been shown to occur rather quickly in the vessel mainly due to the use of impeller with increased diameter. Just-suspended impeller speeds for solids dispersion have been measured and correlated with Zwietering’s equation. The values of Zwietering’s s parameter are proposed for a range of liquid fill levels, impeller clearances and baffle arrangements.

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