Fluid Process Engineering

  © AVT.FVT  

Welcome to the Chair of Fluid Process Engineering!

The research of the chair of Fluid Process Engineering (AVT.FVT) covers the three low-temperature thermal separation processes: extraction, crystallization and chromatography, as well as multiphase reaction systems. The chair is headed by Prof. Dr.-Ing. Andreas Jupke.

The aim of our research is to generate a deeper understanding of these separation processes by investigating the underlying fundamental phenomena. Using a combination of experimental and model-based methods, we are able to analyze the occurring phenomena such as kinetic effects and thermodynamic phase equilibria. To this end, mechanistic models as well as data-driven models are used. The models are parameterized and validated by targeted measurements in tailor-made measuring devices with high-resolution measurement techniques.

Based on these findings, we can apply model-based design tools to develop single devices as well as complex separation sequences. Besides commercially available simulation software like CFD, we use in-house simulation models, which have been developed over years at our chair. These simulation models rely for example on a rate-based, population balance or compartment-based approach. We also use these tools to develop model-based methods for an optimal selection of extraction solvents or adsorbents.

To intensify processes, reaction and separation techniques can be integrated. A current example is the in situ product separation by extraction. Equilibrium conditions, product inhibition or undesired subsequent reactions often limit the yield and selectivity of a reaction. By extracting the target component into a second liquid phase, yield and selectivity increase significantly.

Another key topic is the electrification of thermal separation processes. The integration of electrochemical process steps into separation sequences enables closed recycle streams within the process, which reduces the use of auxiliary materials and minimizes waste production. One concept that has been successfully demonstrated is the integrated electrochemical regeneration of acid and base to avoid salt waste in biotechnology processes. In this context, an electrified pH-swing reactive extraction and an electrochemically induced crystallization process for the recovery of bio-based carboxylic acids have been developed. Other process intensification technologies investigated at our chair include centrifugal extraction as well as reactive and microgel-assisted extraction.

In terms of the application, our research is primarily directed at the development of new processes in the context of bioeconomy, circular economy and renewable energy. The goal for example of bioeconomy processes is to facilitate the change from fossil to renewable raw materials. The increasing use of renewable raw materials and biotechnological syntheses lead to an increased use of extraction, crystallization and chromatography. Compared to distillation, these separation techniques need less energy and allow the processing of temperature-sensitive products. While petrochemical processes predominantly require separation of non-polar fossil raw materials in organic solvents, the recovery of highly functionalized components from biomass primarily takes place in aqueous liquid-phase processes. The effects of accompanying components from biomass or biochemical conversion on the fundamental phenomena of extraction, crystallization, and chromatography are still poorly understood.

The use of fluctuating renewable energy has increased. This poses a challenge on separation processes in general, as they may need to be operated more dynamically in the future. The ongoing digitalization of the process industry as well as the development of new sensor technology offer a wide range of potential improvements for the design and operation of separation processes. Extraction, chromatography and crystallization processes additionally make an important contribution towards a circular economy due to their use in the recycling of different residual material streams. For example, we develop processes for the conversion of CO₂ and H₂ in multiphase reactions, for the recovery of metals and rare earths, and for the separation of depolymerized plastics.

The resulting variety of processes and approaches, as well as their transfer to an industrially relevant scale, pose many new challenges for the development of separation technologies. We work in close cooperation with a large number of research institutes at RWTH Aachen University as well as external partners to realize an interdisciplinary and holistic approach to overcome those challenges. In our AVT’s in-house biorefinery we transfer the separation methods and entire processes developed in laboratory to technical scale. In doing so, we are able to study the fundamental phenomena and mechanisms on a technical scale and to analyze scaling effects thereof. In a current research project, an entire process for the production of a platform chemical from renewable raw materials is being scaled up to a technology readiness level (TRL) of six and evaluated techno-economically. This is a necessary step to transfer new products and processes from laboratory to their technical implementation.