This article is a publication of existing design information and practices with additional information gained from continued operation of the B&P process Equipment Podbielniak Liquid- Liquid contactors (Also referred to as “Pods”). These machines can improve separation and / or extraction compared to what may be achievable at 1X Earth Gravity extraction/ stripping or phase separation, such as in a stripping/ extraction columns, packed towers, or similar units. The rotation can provide up to several thousands of equivalent Gravities (G’s) and additional turbulence that can improve the separation/ rectification / extraction capability of the processes.
Continuous Liquid-Liquid contacting in a centrifuge is found in all aspects of chemical handling processes. Some examples are Pharmaceutical or other fermentation processes, fats and oil washing and separation, Petrochemical refining applications such as acidulation/ saponification, Vitamin & Essential Flavor oil extraction, Metal Ion Liquid extractions, simple phase separations and many others. The use is potentially any application where there are two or more immiscible or partially immiscible liquids with a specific gravity difference as low as 0.01 are to be contacted together- either for mass transfer, separation or reaction purposes.
Due to the small size of Podbielniak contactor relative to other separator technologies (such as towers), the process involved equipment can take up less plant floor space. Additionally, this requires less in-process held up material. Since Liquid-Liquid contacting is a process specific application new potential users of this technology are often unaware of its benefits.
This article will cover the basics for scale-up, design, operation, and extraction performance for a well known example liquid- liquid contacting chemical process application (Extraction of Acetic acid with Water from Methyl Isobutyl Ketone). Process implications for centrifuge operation parameters, such as Rotational speed, feed rate variation and process capacity determination, will be covered in brief.