Multistage Extraction

  • Countercurrent extraction
  • Bench top to plant scale
  • PLUG & RUN
  • High extraction efficiency

Description

Multistage Liquid Liquid Extraction (LLE) is a process where extraction steps are repeated in order to increase the recovery of a product. This process is required when, due to a small partition coefficient, the recovery in a single extraction step is insufficient.

In industrial applications, LLE is most often arranged with a “countercurrent scheme” (CC-LLE) that provides the smallest consumption of extractant. In this scheme, the aqueous raffinate from one stage is fed to a former stage as a feed while the organic phase is moved in the opposite direction. Hence, even if the recovery of product in each stage is small, the overall system can achieve a high level of recovery.

In other words, with multistage extraction, selectivity of the extraction and process yield are decoupled as the yield depends on the number of extraction stages used, thus providing greater freedom to the process developer.

Important features:

  • Only existing tool for bench countercurrent liquid-liquid extraction process development
  • Minimal internal volume
  • ~3ml per stage
  • Easily scalable with our larger separators
  • Easy to use and clean
  • Simple to add/remove extraction stages
  • Addresses the most difficult extractions
  • High extraction efficiency

Why is this System Helpful?

  • Each extraction stage is obtained by first contacting the two phases to achieve mass transfer and then phase separation is obtained with SEP-10.
  • Our process implementation reaches Theoretical Efficiency

Fig 1 – Multistage extraction efficiency

  • The power of multistage extraction can be seen in Fig 1 which shows the extraction efficiency of three different systems with a partition coefficient of 1 (50/50 partitioning of solute).
  • As the number of stages increases, extraction efficiency increases, while still using the same amount of material that would be used if only one batch step was performed.
  • Zaiput can assist you in modeling your expected extraction efficiency for different scenarios.

This system address 3 key challenges typically encountered in developing multi-stage LLE: lack of information, lack of material and difficulty in scale up.

  • Lack of Information. In Multicomponent Systems, Equilibrium data are generally obtained by thermodynamic models (e.g. UNIQUAC, NRTL) but they are often inaccurate due to (1) lack of equilibrium data, (2) unavailable physical property data, especially for unidentified molecular species. As a result, experimental work is needed.
  • Lack of material. CC multistage Extraction is difficult to simulate in laboratory experiments with standard equipment; many experiments and large amounts of material are required. This platform needs 1 to 2 orders of magnitude less material per experiment than any other method.
  • Difficult scale up. Scalability of CC-LLE is challenging with standard equipment (centrifuges, columns, mixer settlers); requires a lot of time and material for optimization. This platform offers seamless scalability up to production.
Technology Mixer Settler
Columns
Centrifuges
Zaiput
Typical Internal Volume per Stage at Lab scale (ml) 25-100 150 100 3

How It Works

Process Description

  • Our MS-10 platform offers an easy to use device to run and optimize CC-LLE processes at the laboratory scale by leveraging our membrane based separation technology and lab scale device SEP-10.
  • Fig 1 outlines the standard plumbing of the system. Interstage pumping is required in CC-LLE to allow the solvent of a step to be used upstream as a feed.
  • Each extraction stage is obtained by first contacting the two phases (mass transfer is achieved inside a portion of tube with two phase flow—black lines in fig 1) and then phase separation is obtained with SEP-10.
  • MS-10 has been designed with 5 extraction stages; fewer stages can be obtained by excluding some devices, more stages can be obtained by adding another platform in series.

Fig 1. Schematic of the standard system plumbing

Device Description

  • MS-10 (fig 2) captures the process shown in (fig 1) using five SEP-10s and a variety of components outlined below:
  • Interstage pumping is achieved using a small diaphragm pump in conjunction with Zaiput ’s Pulsation Dampener (DMP-10) to achieve smooth flow in a compact space.
  • Tube coils for mass transfer are wound onto supports and can be replaced; their length can be optimized to achieve full equilibrium at each stage (as a result the process efficiency will approach theoretical values).
  • Electrical Switches allow pump exclusion (if less than 5 stages are in use), a knob allows control of the interstage pump flow rate to help eliminate air at system start-up.
  • The unit has also quick release bays for hot-swapping and to facilitate system maintenance.
  • The system frame is made of Stainless Steel to provide solvent resistance and excellent durability.
  • The utilization of standard fittings allows the user to customize the process scheme, if needed.
  • For operation it needs only external metering pumps to supply aqueous and organic. External metering pumps are not provided with the device.
  • The very small internal volume (~3ml per stage) results in a quick time to steady state and low consumption of material for process optimization/ experimental data collection. Its internal volumes are 1 to 2 orders of magnitude less than alternative LLE extraction technologies.

Fig 2. Multistage Liquid-Liquid Extraction Platform

Process Scale Up

  • A process that has been optimized at the laboratory/bench scale can be scaled up using our pilot plant units (SEP-200) or production scale units (SEP-3000).
  • Set up for the larger units is typically customized for the specific application/ process developed at the MS-10 scale. Contact us for assistance.

Benchmarking Performance

Below we report the extraction of acetone from water with toluene (this is a solvent system used in literature to benchmark Multistage extraction systems). We plot the overall acetone recovery vs. number of stages used. We report the experimental results and data obtained with ASPEN simulation assuming 100% extraction efficiency at each step.

There are two results to highlight:

  • Increased number of stages increases recovery
  • Maximum extraction efficiency. The extraction efficiency approaches the maximum theoretical limit. This is inferred from the fact that simulated and experimental values are (within error) the same: thus providing a proof that the system works at each stage as an equilibrium system.

Literature

Nopphon Weeranoppanant and Andrea Adamo, In-Line Purification: A Key Component to
Facilitate Drug Synthesis and Process Development in Medicinal Chemistry
, ACS Med. Chem.
Lett.
, Dec 2019.

René Lebl, Trevor Murray, Andrea Adamo, David Cantillo, C. Oliver Kappe, Continuous Flow
Synthesis of Methyl Oximino Acetoacetate: Accessing Greener Purification Methods with Inline Liquid-Liquid
Extraction and Membrane Separation Technology
, ACS Sustainable Chem. Eng.
, Nov 2019.

Scientific research articles relating to our multistage extraction platform:

Nopphon Weeranoppanant, Andrea Adamo, Galym Saparbaiuly, Eleanor Rose, Christian Fleury, Berthold Schenkel, and Klavs F.
Jensen, Design of
Multistage Counter-Current Liquid–Liquid Extraction for Small-Scale Applications
Ind. Eng. Chem.
Res.
Apr 2017.

Yi Shen, Nopphon Weeranoppanant, Lisi Xie, Yue Chen, Marcella R. Lusardi, Joseph Imbrogno, Moungi G. Bawendi and Klavs
F. Jensen, Multistage extraction platform for highly efficient and fully continuous
purification of nanoparticles
Nanoscale
Mar 2017.

Maryam Peer, Nopphon Weeranoppanant, Andrea Adamo, Yanjie Zhang, and Klavs F. Jensen, Biphasic catalytic hydrogen peroxide oxidation of alcohols in flow: Scale up and extraction
Org. Process Res. Dev.
Aug 2016.

Specifications

Contact us if you need more than 5 stages. Platforms can be easily connected together.

Part Number MS10-5
Width 500 mm (19.7 inches)
Depth 400 mm (15.7 inches)
Height 155 mm (6.1 inches)
Total flow rate 0-10 ml/min
Wetted parts:
Separators ETFE, PFA, FEP, PTFE
Tubing/ flow sensors PFA
Interstage pumps FFMK, PVDF
Ports 1/4-28 Flat bottom
Max temperature of operation 80°C
Hold-up volume per stage ~3 ml

Contact us if you need to operate at larger flowrates (from 10 ml/min to 3000 ml/min) for a customized MS-200 extraction platform (up to 200 ml/min) or MS-3000 extraction platform (up to 3000 ml/min).

Ordering Information