423127 Multistage Countercurrent Liquid-Liquid Extraction Enabled By Membrane-Based Separations

Wednesday, November 11, 2015: 3:15 PM
155E (Salt Palace Convention Center)
Nopphon Weeranoppanant, Andrea Adamo, Galym Saparbaiuly and Klavs F. Jensen, Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA

AIChE 2015: Separation Divisions

Sessions: Developments in Extractive Separations


Title: Multistage Countercurrent Liquid-Liquid Extraction Enabled by Membrane-Based Separations

Author: Nopphon Weeranoppanant, Andrea Adamo, Galym Saparbaiuly, and Klavs F Jensen

Liquid-liquid extraction is often the most common workup strategy in the pharmaceutical production due to its high selectivity and large capacity at relatively small energy consumption. In many cases, multiple stages of extraction are required to achieve a high degree of separation. Industrially, mixer-settlers, centrifugal extractors, spray and tray columns are widely used. However, they have the disadvantages of excessively large footprint, limited flow capacity, and difficult scale-up procedures. Their moving parts and/or gravity-driven operation complicate, and in some cases preclude, their use on a laboratory scale. In this work, we construct a multistage countercurrent liquid-liquid extraction at the ml/min scale. The membrane-based separators are used to separate the two phases at each extraction stage, depending on their wettability nature and pressure differential across the membrane. By virtue of an integrated pressure control element that ensures successful separation and decouples the operation from downstream pressure, the setup is greatly simplified. The use of multichannel peristaltic pump as a means of interstage pumping significantly reduces the number of pumps required. We demonstrate two classical examples of solvent recovery: (1) extraction of acetone from an aqueous solution using toluene, (2) extraction of acetic acid from an aqueous solution with ethyl acetate, representing systems with relatively high and low interfacial tensions, respectively. Increasing number of stages is shown to significantly increase the degree of recovery. The extraction of the aqueous acetone solution with mass fraction of 0.50 using toluene, with a solvent-to-feed ratio of 1:2 yields 49.6%, 73.4%, 81.1%, and 94.9% recovery for 1, 3, 5, and 7 stages, respectively, and these are found to be in a close agreement with the simulation assuming 100% extraction efficiency.  Similarly, the extraction of the aqueous acetic acid solution with mass fraction of 0.05 with a solvent-to-feed ratio of 4:1 yields 64.6%, 77.9%, 93.3%, and 99.6% recovery for 1, 3, 5, and 7 stages, respectively. Scale-up strategies, yielding high extraction efficiency at short residence time, are also presented.

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See more of this Session: Extractive Separations Fundamentals and Design II
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