Why does this project matter?

Separation and purification account for 40 – 80% of operating costs in (bio)chemical processes, yet are invariably designed for a fixed operating point. When feedstock composition, product concentration, or throughput changes, which is inherent in bio-based value chains, conventional separation equipment quickly operates outside its design window. P7 asks how separation units can be designed and operated to be genuinely tolerant of load and composition variations without sacrificing efficiency, focusing on polyunsaturated fatty acid (PUFA) recovery from fermentation broth of variable composition: a real, industrially relevant separation challenge at the heart of the TALENT value chain.

What are we aiming to achieve?

P7 aims to develop robust, flexible, and scalable lab-scale separation processes for PUFA-containing streams from LCB fermentation. Core objectives are: (1) identify suitable solvents using chemometric selection tools; (2) characterize and expand the operational flexibility of two extraction column types with respect to throughput, phase ratio, temperature, and feed concentration; (3) quantify the flexibility range via process simulation in DWSIM; (4) investigate back-extraction and closed solvent cycles for process circularity; and (5) develop a modeling and simulation toolbox for tolerant separation equipment.

What will you work on as a PhD researcher?

As doctoral researcher in P7, you develop and characterize a flexible solvent extraction process for PUFA recovery from fermentation broth. You start by comprehensively characterizing the feed stream from P2 (fatty acid composition by GC-MS, aqueous co-solutes by HPLC, physical properties including density, viscosity, and interfacial tension). Solvent selection is then performed using a chemometric approach based on principal component analysis (PCA) of molecular descriptors, allowing systematic screening without exhaustive experimental testing.

You set up and operate two lab-scale extraction columns, a stirred-pulsed Kühni-type and an internally-pulsed Karr-type, systematically varying solvent-to-feed ratio, pulsation parameters, temperature, and column loading. Separation performance and hydrodynamic behavior are characterized, and column internals are adapted to expand the operational window. Integrated in-line sensors (UV/Vis, Raman, HPLC) connected to the adaptive Model Predictive Control (MPC) system in P8 enable closed-loop control. Purified PUFA extracts are forwarded to P3, and all process data feed into the techno-economic and life cycle assessment (LCA) in P9.

Skills and methods you will develop during your doctorate:

• Liquid-liquid extraction: column design, hydrodynamics, stage efficiency analysis

• Chemometric solvent selection: PCA, molecular descriptor analysis

• Analytical chemistry: UV/Vis, Raman, GC, HPLC

• Process instrumentation: in-line sensor integration, control interfaces

• Process simulation with DWSIM: steady-state and sensitivity analysis of separation units

• Experimental design (DoE) for efficient process characterization

Who will you work with and where?

The Kockmann group has long-standing expertise across the full portfolio of continuous flow separation technologies at lab scale, including liquid-liquid extraction, distillation, crystallization, and filtration, with particular strength in smart equipment design: integrating sensors, automation, and chemometric tools for real-time process monitoring and control. The laboratory is equipped with pulsed Kühni-type and Karr-type extraction columns, a spinning band column for continuous distillation, a draft tube baffle crystallizer for vacuum crystallization, miniaturized mixer-settler units, and a broad range of inline sensors (optical and electrical). The group additionally holds expertise in process simulation with DWSIM and in research data management within the NFDI4Cat initiative. Embedded in RTG TALENT, you gain access to a structured qualification program that combines advanced scientific training with transferable skills development, active exchange with academic and industrial collaboration partners, and tailored career support including the opportunity for a three-month placement in research, industry, or a start-up aligned with your career goals.