TY - CHAP A1 - Wörthmann, Mario A1 - Lindner, Johannes A. A1 - Briesen, Heiko ED - Dechema, T1 - Gezieltes Einstellen der Schutzwirkung homogener Schmelzcoatings T2 - Jahrestreffen der ProcessNet-Fachgruppen Lebensmittelverfahrenstechnik, Mischvorgänge und Grenzflächenbestimmte Systeme und Prozesse 2021 Y1 - 2023 ER - TY - GEN A1 - van den Berg, Gregor A1 - Lindner, Johannes T1 - Beschichtung von Partikeln in der pneumatischen Förderung Y1 - 2024 ER - TY - GEN A1 - van den Berg, Gregor A1 - Lindner, Johannes T1 - Coating of Particles in Pneumatic Conveying N2 - Coating is an important process in the chemical, food and pharmaceutical industry for applying flow agents, adding colorants, applying a protective layer against humidity, for the selective release of the contents or applying a flavor layer to goods. This is usually done in a fluidized bed (Wurster coater) or a coating drum. Pneumatic conveying systems are usually already installed for conveying particulate media, for example between process steps or the filling. In pneumatic conveying, the fluidized state of the Wurster Coater is already present. The basic idea of the current project is to implement the coating step directly in the pneumatic conveying system. Experimental approach: The coating tests were carried out using a vacuum system. For this purpose, various coating chambers with different nozzle arrangements were printed using a rapid prototyper. The nozzles used were also printed in-house and adapted to the requirements. Particles with a diameter of 3 mm were used for the tests and sprayed with a common protective coating as well as blue dye. The particles were heated to 120°C in order to supply the necessary heat to evaporate the solvent. Images of the coated particles were taken and evaluated with ImageJ to analyze the coating result. The amount of coating delivered changes the coating layer linearly as expected. The tests showed that it is possible to coat particles during pneumatic conveying. A comparison with coating in a Wurster coater showed that the amount of overspray is higher than in a Wurster coater, leading a lower efficiency in the coating step in pneumatic conveying though. KW - Coating; pneumatic conveying; two-fluid nozzles; rapid prototyping; additive manufacturing nozzles; in-line particle coating Y1 - 2026 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:861-opus4-31678 ER - TY - JOUR A1 - Stromeck-Faderl, A. A1 - Pentlehner, Dominik A1 - Kensy, U. A1 - Dick, B. T1 - High-resolution electronic spectroscopy of the BODIPY chromophore in supersonic beam and superfluid helium droplets JF - CHEM-PHYS-CHEM, Special Issue: Laser Chemistry and Spectroscopy N2 - We present the fluorescence excitation and dispersed emission spectra of the parent compound of the boron dipyrromethene (BODIPY) dye class measured in a supersonic beam and isolated in superfluid helium nanodroplets. The gas‐phase spectrum of the isolated molecules displays many low‐frequency transitions that are assigned to a symmetry‐breaking mode with a strongly nonharmonic potential, presumably the out‐of‐plane wagging mode of the BF2 group. The data are in good agreement with transition energies and Franck–Condon factors calculated for a double minimum potential in the upper electronic state. The corresponding transitions do not appear in the helium droplet. This is explained with the quasi‐rigid first layer of helium atoms attached to the dopant molecule by van der Waals forces. The spectral characteristics are those of a cyanine dye rather than that of an aromatic chromophore. KW - Helium nanodroplets KW - Electronic spectroscopy KW - BODIPY Chromophore Y1 - 2011 IS - 12 ER - TY - JOUR A1 - Slenczka, Alkwin A1 - Pentlehner, Dominik T1 - Electronic spectroscopy of 9,10-dichloroanthracene inside helium droplets JF - The Journal of Chemical Physics N2 - The spectroscopy of molecules doped into superfluid helium droplets provides information on both, the dopant molecule and the helium environment. Electronic spectra of 9,10-dichloroanthracene in helium droplets are presented and compared with corresponding gas phase spectra to unravel the influence of the helium environment. The combined investigation of fluorescence excitation and dispersed emission provides information on dynamic processes in addition to energetic conditions. For vibronic states, the helium induced decay channels dominate over all intramolecular channels that contribute to the gas phase behavior. In addition to the triplet splitting caused by the Cl isotopes, a fine structure resolved for all transitions in the fluorescence excitation spectrum was found, which is the signature of microsolvation of this compound in helium droplets. This fine structure is identified as a single pure molecular transition accompanied by a sharply structured phonon wing. The corresponding fine structure measured for bare anthracene shows remarkable differences. KW - Helium nanodroplets KW - Emission spectroscopy KW - Doppler effect Y1 - 2013 IS - 138 ER - TY - CHAP A1 - Schwarz, Benedikt A1 - Lindner, Johannes A. ED - Dechema, T1 - Automatisierte Prozessoptimierung durch einen adaptiven, dynamischen Mischer T2 - Jahrestreffen der DECHEMA-Fachgruppen Extraktion und Mischvorgänge Y1 - 2023 ER - TY - CHAP A1 - Schwarz, Benedikt A1 - Lindner, Johannes T1 - Automated Process Optimization in Mixing with Adaptive and Dynamic Mixing Modes T2 - PARTEC 2025 N2 - Mixing plays a crucial role in industry, for e.g., fine and petrochemicals, food, pharmaceuticals, and mineral processing. The selection of the stirrer is based on the desired flow pattern and the rheological properties of the material being processed. A change in the mixing task or a significant shift in material properties during the process can lead to decreased efficiency, longer mixing times, or poorer mixing quality. To address the need for handling various tasks across a wide range of applications with the same mixer, a multi-purpose mixer with adjustable tools was developed. It consists of a coaxial stirrer with an inner and an outer stirrer. The blades of the inner stirrer can be changed in inclination during the process. This allows different tasks, such as dispersion, aeration, and suspension, to be performed efficiently in succession without the need for tool changes. Additionally, the process parameters can be dynamically changed to compensate for changes in the process. Energy input into the fluid serves as a key parameter to quantify the quality of a dispersion process. The three independent actuators can be used to achieve the best energy input. To identify the optimal settings, a control algorithm called the "automated design of experience" was developed. This algorithm adjusts the speed of the main and coaxial stirrers and the blade angle in a sequential manner, evaluating whether these changes lead to improved or worsened energy input. It is hence possible to determine optimum mixing parameters in an automated way. KW - Dynamic Mixing Y1 - 2025 ER - TY - GEN A1 - Schwarz, Benedikt A1 - Lindner, Johannes T1 - Variable volume flows in a hydrocyclone by changing the inlet geometry during the process T2 - PARTEC 2025 N2 - Motivation: Hydrocyclones are designed for a specific operating point but react badly to a change in operating conditions. Reducing the flow rate results in lower centrifugal forces and hence separation efficiency. Increasing the flow rate increases the pressure loss, while the separation efficiency suffers from increased turbulence. It is also not possible to react to modifications of the material or liquid phase to be separated. The aim of the present development is to create a cyclone that can react to variable operating parameters to keep the separation efficiency at a high level. Material & Methodology: Good separation in cyclones requires a stable formation of the secondary vortex, which can be characterized by high tangential flow velocity (Schubert 2003). By implementing a variable cross-section in the inlet channel, the feeding velocity into the cyclone can be kept constant at changing flow rates to maintain the secondary vortex and keep comparable separation efficiency and pressure loss. An inline turbidity measurement at the upstream outlet can be used to monitor dynamically the separation efficiency. The variable cross-section area can be controlled depending on the fluctuating volume flow or on a specific outlet concentration based on the measured turbidity. Experiments showed that operating the system at a constant pressure loss improves the separation efficiency despite a reduction of the volume flow. Efficient separation at different or even fluctuating volume flow is hence possible. KW - Mixing Y1 - 2025 ER - TY - JOUR A1 - Schwarz, Benedikt A1 - Krause, Peter A1 - Lindner, Johannes T1 - A Dynamic Hydrocyclone Adapting to Different Operating Points by Changing the Inlet Area JF - Chemical Engineering and Technology N2 - In this study, a novel hydrocyclone design was developed featuring a variable inlet geometry, which enables adjustment of the inlet area during operation. This allows control over the flow velocity within the cyclone, thereby maintaining a constant tangential velocity despite changes in volumetric flow rate. The prototype demonstrated a constant separation efficiency across a volumetric flow range spanning a factor of two between its minimum and maximum capacities. Two control strategies were investigated: operation at constant pressure drop and operation at constant inlet velocity, both under varying flow rates and inlet geometries. To initially examine the influence of key parameters, hydrocyclones with fixed geometries were fabricated using rapid prototyping and employed in experimental trials. These findings informed the subsequent development and construction of a dynamically adaptive steel prototype capable of dynamic geometrically adjustment. KW - dynamic hydrocyclone KW - particle separation KW - solid–liquid separation Y1 - 2026 U6 - https://doi.org/10.1002/ceat.70154 PB - Wiley-VCH CY - Weinheim ER - TY - JOUR A1 - Schwarz, Benedikt A1 - Kniele, H. A1 - Lindner, Johannes T1 - Automated Process Optimization in a Novel TripleShaft Mixer with Adaptive Mixing Modes JF - Chemie Ingenieur Technik N2 - A novel multi-purpose mixer was set up, which allows the change of the blade angle during the process and provides aflow field with respect to the needs of the mixing task. It features as well as a coaxial stirrer for highly viscous liquids andhence has three degrees of freedom. The stirrer considers the integration and validation of an optimization strategy forthe autonomous identification of an optimum operating point based on automated tests. The validation was conducted ina mixing process with several process input parameters, which is commonly used in industrial applications. The powerdraw of the main stirrer was used as a optimization parameter, representing the power used for dispersing. The speedand direction of the main and secondary stirrers, respectively, as well as the angle of the stirrer blades, were used as inputprocesses. The proposed control scheme automatically identifies and corrects drops in energy dissipation rates. KW - Mixing KW - Optimal operation KW - Reinforcement learning KW - Self-optimization Y1 - 2025 U6 - https://doi.org/10.1002/cite.70060 PB - Wiley-VCH CY - Weinheim ER -