Lehrstuhl Anlagen- und Prozesstechnik
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Item Development of an automated adsorbent selection strategy for liquid–phase adsorption(2022-04-06) Schreiber, Mareike; Schembecker, GerhardA systematic and automatic approach for adsorbent selection for liquid–phase adsorption is proposed. Based on physical properties like polarity, pore size, and specific surface, a screening strategy is developed and automated on a robotic platform. Key performance indicators are applied ensuring economically based decisions. The approach developed is verified by adsorption of caffeine out of an aqueous solution with vanillin, uracil, and α–ionon as impurities. The adsorbent selection strategy leads to the polymeric adsorbent SP207 and a specific surface of 15 m2mL−1 ending in a separation cost indicator of 16 € gCaffeine−1. This work proposes an opportunity for accelerated process design strengthened by the usage of robotic devices.Item Modeling of continuous slug flow cooling crystallization towards pharmaceutical applications(2023-09-04) Kufner, Anne Catherine; Rix, Michael; Wohlgemuth, KerstinThe rising trend towards continuous production in the field of small-scale crystallization has generated many creative concepts for apparatuses for the production of active pharmaceutical ingredients. One of these promising apparatuses is the Slug Flow Crystallizer (SFC), which enables the adjustment of the particle size distribution and the achievement of high yields through its alternating slug flow. To realize and understand the crystallization inside the SFC, high experimental effort has been necessary until now. Therefore, a mechanistic model considering the hydrodynamics of slug flow, the energy and mass balances, and the crystallization phenomena of growth and agglomeration inside the apparatus was developed. Its purpose is to improve the understanding of the process, estimate the effects of operating parameters on target properties, and predict crystallization behavior for different substance systems with minimal experimental effort. Successful modeling was validated with experimental results for the substance system l-alanine/water. Furthermore, the robustness of the model was evaluated, and guidelines were presented, enabling the transfer of the model to new substance systems.Item Off-the-rack instead of tailor-made module-based plant design at equipment level(2022) Radatz, Heiko; Schembecker, Gerhard; Grünewald, MarcusModule-based plant design facilitates a paradigm shift in chemical and biochemical industry to decrease the time needed for plant design. Instead of a tailored design of apparatuses for a target production rate, modules are selected off-the-rack to set up a production plant. Within the scope of this thesis, four important areas of module-based plant design at equipment level are investigated. First, the determination of a plants’ overall operating window, a prerequisite for equipment module selection and evaluation is improved by considering the so far neglected non-linear dependency between the operating constraints and the production rate of a plant. Second, the currently accepted view that investment costs are determining the decision on the use of equipment modules for different process units is disproved and novel preselection approaches are proposed, applied and evaluated. A preselection approach based on investment and operating costs is rated most suitable to decide on the use of equipment modules for a case study. The third area explored is equipment module selection for a constant market demand, aiming at flexibility in production rate at low investment costs, as well as for a market demand development. It is shown by case studies that modular production plants offer a promising alternative to conventionally designed plants. Finally, an approach to design equipment modules for flexibility in production rate is introduced and applied. For the case study of a heat exchanger it is shown that a four times larger operating window can be obtained at only 14 % higher total annual costs compared to a conventionally designed heat exchanger. Hence, this work investigates four key areas in module-based plant design at equipment level beyond current state of the art contributing to a paradigm shift in plant design.Item Extraction on a robotic platform - autonomous solvent selection under economic evaluation criteria(2021-06-21) Schreiber, Mareike; Brunert, Manuel; Schembecker, GerhardSteps and necessary decisions for a liquid-liquid extraction were pointed out for its automatic design on a robotic platform. A tool for solvent selection based on Hansen parameters was developed to simplify solvent selection. An approach was developed for automatic, visual phase boundary detection. Key performance indicators are used to ensure economically motivated decisions. The autonomous design of an extraction process is demonstrated for the separation of progesterone from a fermentation broth. The method leads to the selection of methanol and acetonitrile, with separation cost indicators of 146 and 183 € gProg.−1. This work constitutes the prospects of using autonomous robotic systems to design entire production processes.Item Application of rotating packed bed for in-line aroma stripping from cell slurry(2020-05-20) Lukin, Ilya; Wingartz, Isabell; Schembecker, GerhardBACKGROUND Nowadays, biotechnological production receives increasing interest as an alternative source of natural aromas. Unfortunately, especially for hydrophobic and semi-volatile aromas, the heterogeneous product partitioning between all phases present in fermentation makes recovery challenging. Additionally, when an aroma displays an inhibitory effect on the production microorganism, product removal during fermentation is recommendable. In-line aroma stripping offers an elegant way to deal with such challenges. This study reports the use of rotating packed bed (RPB) technology for the intensification of stripping of α-ionone, a key aroma of raspberry, from a model fermentation slurry containing Saccharomyces cerevisiae cells in a concentration of 250 g-CWW L−1. RESULTS Throughout all experimental investigations, yeast cells were robust towards both the chemical stress from aroma exposure at a concentration of up to 400 mg L−1 and the mechanical stress from peripheral equipment and rotation of up to 2750 rpm, as a maximum of 11.3 ± 0.5% disrupted cells were measured during continuous processing in an RPB. An increase in the rotation speed led to an enhanced transfer of α-ionone from the fermentation slurry to the gaseous phase. CONCLUSIONS RPB technology is found to be promising for the intensification of in-line stripping of biotechnologically produced aromas from crude fermentation broth without cell separation. The use of subsequent RPBs equipped with custom packings and flexibly adjustable rotation speed displays a holistic aroma recovery process supporting the way to commercial competitiveness of biotechnological aromas. © 2020 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Item Aroma absorption in rapeseed oil using rotating packed bed(2020-10-05) Lukin, Ilya; Pietzka, Lukas; Wingartz, Isabell; Schembecker, GerhardAn increasing consumers’ call for natural aromas fuels the development of biotechnological aroma production. Although aroma fermentation is quite advantageous, especially severe product losses of volatile compounds through the bioreactor off-gas may challenge the downstream processing. The application of novel process intensification methods to overcome the common drawbacks of conventional apparatuses might be helpful on a way to commercial competitiveness of biotechnological aromas. This study explored the suitability of rotating packed bed (RPB), a rotating mass transfer enhancing machine, for the absorption of model aroma compounds in rapeseed oil. Increasing the rotation speed from 500 to 2750 rpm led to two- to threefold higher absorption efficiencies at elsewise constant conditions. Aiming for an enriched aromatic intermediate, 2.5 L of rapeseed oil was processed in a recycle for 200 minutes, and a final concentration of benzaldehyde of 0.323 ± 0.026 g/Loil was achieved. Compared to packed columns, the RPB outperforms at equal packing depth or requires less packing area to deliver same efficiency. Especially, the use of custom 3D-printed spiral packing with elaborated wall film flow combined with rotation supported liquid distribution allows using absorbents with viscosities as high as 100 mPa·s at low pressure drop increase. However, small dimensions severely limit the performance of a laboratory-scale RPB as the casing contributes disproportionally to mass transfer.Item Mass transfer of proteins in aqueous two-phase systems(2019-03-06) Kaplanow, Irene; Görzgen, Fabian; Merz, Juliane; Schembecker, GerhardAqueous Two-Phase Extraction is known to be a gentle separation technique for biochemical molecules where product partitioning is fast. However, the reason for the high mass transfer rates has not been investigated, yet. Many researchers claim that the low interfacial tension facilitates the formation of very small droplets and with it a large interfacial area causing a fast partitioning. However, an experimental evidence for this hypothesis has not been published yet. In this study, the mass transfer coefficients of two proteins, namely lysozyme and bromelain, were determined by providing a defined interfacial area for partitioning. Compared to low molecular weight solutes the mass transfer coefficient for the proteins investigated was small proving for the first time that the large interfacial area and not fast diffusion seems to be the reason for fast protein partitioning.Item Measurement and control of agglomeration for the design of crystalline products(Verlag Dr. Hut, 2016) Terdenge, Lisa-Marie; Schembecker, Gerhard; Ulrich, Joachim