@article{LindnerMuellerBriesenetal.2021, author = {Lindner, Johannes A. and M{\"u}ller, M.G. and Briesen, H. and Foerst, P.}, title = {Monitoring temperature evolution and drying of coating on a single fluidized particle by infrared thermography}, series = {Powder Technology}, volume = {382}, journal = {Powder Technology}, pages = {331 -- 338}, year = {2021}, abstract = {Coating is an important step for the protection of drugs and flavors in the pharmaceutical and food industry. This paper presents a method for the experimental investigation of the coating process of a single freestream-fluidized particle by an infrared camera. The coating is dispersed by a nozzle with ultrasonic fluid atomization, allowing constant droplet size at different spray rates. The temperature of the fluidized particle was measured online by an infrared camera. The application of the coating on the particle in a spray cycle and the subsequent solvent vaporization is linked to the temperature and hence monitored during the whole coating process. The cyclic coating process of a Wurster coater is hence reproduced. The temperature evolution for different coating amounts in a single spray cycle, for different particle sizes, materials and temperature levels is monitored. A micro-computed tomography image shows the result of the levitator coating, giving a homogeneous layer.}, language = {en} } @article{WoerthmannLindnerKovacevicetal.2021, author = {Woerthmann, B.M. and Lindner, Johannes A. and Kovacevic, T. and Pergam, P. and Schmid, F. and Briesen, H.}, title = {A novel method for assessing the coating uniformity of hot-melt coated particles using micro-computed tomography}, series = {Powder Technology}, volume = {378}, journal = {Powder Technology}, number = {Part A}, pages = {51 -- 59}, year = {2021}, abstract = {The effectiveness of hot-melt coating depends on its uniformity and the extent to which the surface is completely covered. Compared with solvent-based coating, spreading is more limited in hot-melt coating; thus, the coating uniformity is more affected by the process parameters. This study presents a new method for identifying and quantifying factors influencing coating uniformity. The proposed method facilitates the determination of coating-thickness distribution and non-covered surface proportion based on micro-computed tomography measurements. The proposed method is based on particles that have undergone hot-melt coating in a fluidized bed, and it is compared to common methods for layer-thickness determination. The influencing factors are quantified in terms of the dependency of coating uniformity on the coating amount and material. Material properties have a significant impact because stearin and palm fat create different coating layers. The proposed method is confirmed to be well suited for analyzing coating qualities.}, language = {en} } @inproceedings{WoerthmannLindnerBriesen2021, author = {W{\"o}rthmann, Mario and Lindner, Johannes A. and Briesen, Heiko}, title = {Gezieltes Einstellen der Schutzwirkung homogener Schmelzcoatings}, series = {Jahrestreffen der ProcessNet-Fachgruppen Lebensmittelverfahrenstechnik, Mischvorg{\"a}nge und Grenzfl{\"a}chenbestimmte Systeme und Prozesse 2021}, booktitle = {Jahrestreffen der ProcessNet-Fachgruppen Lebensmittelverfahrenstechnik, Mischvorg{\"a}nge und Grenzfl{\"a}chenbestimmte Systeme und Prozesse 2021}, editor = {Dechema,}, year = {2021}, language = {en} } @inproceedings{LindnerOrtler2022, author = {Lindner, Johannes A. and Ortler, Matthias}, title = {Zur dynamischen Mischtechnik f{\"u}r die {\"A}nderung des Str{\"o}mungsbilds w{\"a}hrend des Prozessverlaufs}, series = {Jahrestreffen der ProcessNet-Fachgruppen Computational Fluid Dynamics + Mischvorg{\"a}nge + Agglomerations- und Sch{\"u}ttguttechnik}, booktitle = {Jahrestreffen der ProcessNet-Fachgruppen Computational Fluid Dynamics + Mischvorg{\"a}nge + Agglomerations- und Sch{\"u}ttguttechnik}, editor = {Dechema,}, year = {2022}, language = {en} } @inproceedings{KammererLangLindner2021, author = {Kammerer, Matthias and Lang, Roman and Lindner, Johannes A.}, title = {Nutzung der dynamischen Mischtechnik f{\"u}r intelligente Prozesse}, series = {Jahrestreffen der ProcessNet-Fachgruppen Lebensmittelverfahrenstechnik, Mischvorg{\"a}nge und Grenzfl{\"a}chenbestimmte Systeme und Prozesse 2021}, booktitle = {Jahrestreffen der ProcessNet-Fachgruppen Lebensmittelverfahrenstechnik, Mischvorg{\"a}nge und Grenzfl{\"a}chenbestimmte Systeme und Prozesse 2021}, editor = {Dechema,}, year = {2021}, language = {en} } @misc{vandenBergLindner2024, author = {van den Berg, Gregor and Lindner, Johannes}, title = {Beschichtung von Partikeln in der pneumatischen F{\"o}rderung}, year = {2024}, language = {de} } @article{SchwarzOrtlerLindner2024, author = {Schwarz, Benedikt and Ortler, Matthias and Lindner, Johannes}, title = {Rotational speed change and reverse mixing to avoid baffles in dispersing processes}, series = {Chemical Engineering Research and Design}, volume = {206}, journal = {Chemical Engineering Research and Design}, doi = {10.1016/j.cherd.2024.05.004}, pages = {302 -- 309}, year = {2024}, abstract = {Stirring is used for mass and heat transfer, particle suspending or similar processes. It is commonly conducted in a steady operation mode. This paper targets on performing the stirring process dynamically by reversing the rotation direction to introduce additional turbulences and hence accelerating the dispersing processes. The power introduced into the fluid as well as mixing kinetics performing dynamic mixing were studied based on the rotational acceleration, blade pitch angle, liquid volume and duration of the rotational speed direction interval for a vessel equipped with a turbine agitator with and without baffles. Experiments show that baffles are not necessary if reverse mixing is performed at a specific frequency.}, language = {en} } @inproceedings{SchwarzLindner2025, author = {Schwarz, Benedikt and Lindner, Johannes}, title = {Automated Process Optimization in Mixing with Adaptive and Dynamic Mixing Modes}, series = {PARTEC 2025}, booktitle = {PARTEC 2025}, year = {2025}, abstract = {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.}, language = {en} } @misc{SchwarzLindner2025, author = {Schwarz, Benedikt and Lindner, Johannes}, title = {Variable volume flows in a hydrocyclone by changing the inlet geometry during the process}, series = {PARTEC 2025}, journal = {PARTEC 2025}, year = {2025}, abstract = {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.}, language = {en} } @inproceedings{SchwarzLindner2023, author = {Schwarz, Benedikt and Lindner, Johannes A.}, title = {Automatisierte Prozessoptimierung durch einen adaptiven, dynamischen Mischer}, series = {Jahrestreffen der DECHEMA-Fachgruppen Extraktion und Mischvorg{\"a}nge}, booktitle = {Jahrestreffen der DECHEMA-Fachgruppen Extraktion und Mischvorg{\"a}nge}, editor = {Dechema,}, year = {2023}, language = {en} } @inproceedings{SchwarzLindner2025, author = {Schwarz, Benedikt and Lindner, Johannes}, title = {Variabler Volumenstrom beim Hydrozyklon durch Ver{\"a}nderung der Einlaufgeometrie w{\"a}hrend des Prozesses}, series = {DECHEMA/VDI Fachgruppen Mechanische Fl{\"u}ssigkeitsabtrennung}, booktitle = {DECHEMA/VDI Fachgruppen Mechanische Fl{\"u}ssigkeitsabtrennung}, year = {2025}, language = {de} } @inproceedings{SchwarzLindner2025, author = {Schwarz, Benedikt and Lindner, Johannes}, title = {Verk{\"u}rzte Mischzeiten durch Reversieren der Drehrichtung in einem R{\"u}hrkessel}, series = {DECHEMA/VDI Fachgruppen Mischvorg{\"a}nge}, booktitle = {DECHEMA/VDI Fachgruppen Mischvorg{\"a}nge}, year = {2025}, language = {de} } @inproceedings{SchwarzLindner2024, author = {Schwarz, Benedikt and Lindner, Johannes}, title = {An approach to automated process optimization in mixing using adaptive and dynamic mixing modes}, series = {9 th Asian Particle Technology Symposium}, booktitle = {9 th Asian Particle Technology Symposium}, year = {2024}, language = {en} } @article{SchwarzKnieleLindner2025, author = {Schwarz, Benedikt and Kniele, H. and Lindner, Johannes}, title = {Automated Process Optimization in a Novel TripleShaft Mixer with Adaptive Mixing Modes}, series = {Chemie Ingenieur Technik}, journal = {Chemie Ingenieur Technik}, publisher = {Wiley-VCH}, address = {Weinheim}, doi = {10.1002/cite.70060}, year = {2025}, abstract = {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.}, language = {en} } @article{SchwarzKrauseLindner2026, author = {Schwarz, Benedikt and Krause, Peter and Lindner, Johannes}, title = {A Dynamic Hydrocyclone Adapting to Different Operating Points by Changing the Inlet Area}, series = {Chemical Engineering and Technology}, journal = {Chemical Engineering and Technology}, publisher = {Wiley-VCH}, address = {Weinheim}, doi = {10.1002/ceat.70154}, year = {2026}, abstract = {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.}, language = {en} } @misc{vandenBergLindner2025, author = {van den Berg, Gregor and Lindner, Johannes}, title = {Coating of Particles in Pneumatic Conveying}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:861-opus4-31678}, pages = {18}, year = {2025}, abstract = {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.}, language = {en} }