Produktdesign von Kunststoffen für die Waschmittelindustrie

Water soluble polymers in the detergent industry represent on the one hand parts of the formulations of washing powder to improve the washing result, and are used on the other hand as foils for the packaging of liquid detergent portions. Insoluble, thermoplastic polymers (PE, PP, PET) are needed as packaging materials for solids, pastes, suspensions and liquids in the form of laminated cardboard, boxes, bags, bottles, buckets and tubes. The polymers can be tailored to the application. For this purpose, not only the possibilities of the reaction and synthesis technology are available, but the addition of additives manages the adjustment of the required physical, technical and optical properties, such as color and durability. In an extrusion process, the plasticized or melted material gets the product shape; any form can be produced. The packaging should convince not only in forms and functions, but also throughout the aesthetics relating to the specific brand. The product design is the sum of these parameters.     

Enzyme für Waschmittel

The high performance of modern laundry detergents at 30 – 60 °C is only possible with specific enzymes and specially tuned enzyme mixtures. The various enzymes form complexes with the substrates (stains) and hydrolyze the fixed proteins, polysaccharides and fats. Surfactants rinse resulting fragments into the wash liquor. The enzymes are produced by appropriate microorganisms in fermenters with a size of 40 to 125 m³. The microorganisms secrete the enzyme into the medium. After the end of the fermentation, the enzymes are separated from the microorganisms, concentrated and converted into the final product. Here, the enzyme solution is used as granulation liquid. Product safety requires a special coating. The product design is determined by the protein engineering (performance) and the design (convenience) of the particle.     

Erweiterung der Auslegungsverfahren von Rührern und Anwendung an einem Propellerviskosimeter

The design procedure of mixers to agitate non‐Newtonian flow is commonly based on several correlation methods that associate the power consumption of agitating newtonian flow with the power of agitating non‐Newtonian flow. Therefore, the knowledge of the viscosity function of the non‐Newtonian fluid is necessary. For the agitation of fluids with solid fractions, the viscosity is usually unknown and the methods are not applicable. Here, a method to determine the viscosity of pseudoplastic fluids with a solid fraction is presented.     

Produktschonende Betriebs‐ und Designparameter von Wärmeübertragern für temperaturempfindliche Prozessströme

To allow the calculation of product degradation rates as extension to the currently used thermotechnical design calculations for heat exchangers, a volume‐related, reaction‐kinetic approach was developed. Therefore, a model system was selected and the product protection design parameters were determined for a lab‐scale heat exchanger with the help of simulations. The validation was demonstrated in an experiment. Additionally, the product‐protecting operating parameters for the heat exchanger were calculated with a technically relevant set of compounds.     

Modellierung und Simulation von Strömungen und biologischen Reaktionen innerhalb eines Belebtschlammbeckens

With the aim to increase the efficiency of the aeration tanks of municipal wastewater treatment plants, the implementation of a biological model system (ASM1) into the CFD code ANSYS CFX® is presented for modeling a full‐scale aeration tank and verified with experimental data. Taking into account the biological processes, hydrodynamics and gas‐liquid mass transfer, simulations were performed and compared to experimental concentration profiles for ammonium and nitrate. The assumptions made are explained in detail. While the simulated ammonium concentration profile is in good agreement with the measured values, deviations occur for the nitrate profile. However, the CFD simulations exceed the prediction accuracy of conventional 0D simulation software.     

Synthese von porösen Voll‐ und Core‐Shell‐Glaskugeln zur Trennung von chiralen Anästhetika

For the separation of chiral anesthetic gases suitable support materials for the selectors are necessary. Due to the controlled texture properties porous glass shows a high potential for such applications. In this study porous glass beads with particle diameters of 40 – 400 µm and 2 – 4 mm could be obtained via a special fluidized‐bed reactor and the method of ionotropic gelation. Furthermore, the first core‐shell beads on the basis of porous glasses could be synthesized via the combination of an ion‐exchange induced phase separation and a selective leaching step. The new materials are characterized by a defined mesoporous shell and a non‐porous glass core.     

Der Einfluss von Beanspruchungsgeschwindigkeit und Partikelgröße auf das Bruchverhalten von Agarperlen

For the selection and design of enzyme and cell immobilizates the mechanical characterization is of particular importance for their usage in bioreactors. Against this background, a texture analyzer was used to perform rigidity tests on agar pearls with varying agar concentrations. The results suggest the independence of the bursting behavior from surrounding media and a significant dependency from loading speed and particle size.     

Katalysatorrecycling in der homogenkatalysierten Kreuzmetathese von Ölsäuremethylester und 4‐Octen

The recycling of homogeneous metathesis catalysts is a big challenge in alkene metathesis. Within this contribution the recycling of these catalysts is investigated in the cross metathesis of methyl oleate and 4‐octene as model reaction. Fluid‐fluid separation technique and temperature dependent solvent systems allow the separation of the homogeneously solved catalysts from the metathesis products. The catalyst phase was successfully recycled in multiple recycling runs only with minor loss of yield.     

Vergleich von herkömmlichen und reacetylierten Chitosanen hinsichtlich ihrer Flockungseigenschaften

Since for some years chitosan is in the focus of biologically orientated research. It has a huge number of advantages compared to synthetic products. In this work the chitosan was reacetylated and afterwards characterized. Reacetylated chitosan dissolves in deionized water without any additives and shows good flocculation properties. Furthermore the properties of flocculation were compared to commercial chitosan. Molar mass, pH value, and the salinity in the system have great influence on position and width of the flocculation window.     

Scherfließen und Wandgleiten von Massen für den Pulverspritzguss

This contribution presents coupling of laws for shear flow and wall slipping by the shear stress at the slipping interface. It includes the special case of Coulombian friction postulated by Uhland as well as the assumption of a constant sliding velocity along the flow channel according to Mooney. As an example, Ostwald and de Waele's law of shear thinning flow is combined with a shear stress of sliding depending on internal pressure by a power law. Examined feedstocks for metal injection molding showed a rheological behavior according to the model presented.     

Heterogen katalysierte Reaktivdestillation: Design und Scale‐up am Beispiel von Methylacetat

Reactive Distillation by Heterogeneous Catalysis: Design and Scale‐up Using Methyl Acetate as an Example Methyl acetate synthesis and hydrolysis is used to exemplify the design and scale‐up of heterogeneously catalyzed reactive distillations using Katapak‐S/‐SP. Different equilibrium and non‐equilibrium stage models and a rate‐based model are compared in order to clarify the level of complexity needed to predict the process behavior. An equilibrium stage model accounting for reaction kinetics is the best choice for methyl acetate reactive distillation. Reliable information on fluid dynamics of the used reactive distillation packing is needed for the fluid dynamic design in order to assure a wide operation range of the reactive distillation column. To verify the process model, experiments on the synthesis of methyl acetate have been performed in columns with different diameters. As a case study, the model‐based scale‐up is described for an industrial methyl acetate hydrolysis process.