Kinetische Parameteridentifikation und Modelldiskriminierung am Beispiel der nassen Oxidation von Thiosulfat

Coke technology involves polluted wastewater, which must be treated efficiently in order not to pollute the environment and to comply with legal regulations. This requires a thorough understanding of the process. Due to the large number of possible modifications, sulfur compounds occupy a special position and, thus, knowledge of the reaction pathways and kinetics is essential for the design of apparatuses. By means of parameter estimation and model discrimination, kinetics are determined on the basis of experimental data and reaction schemes of the wet oxidation of thiosulfate are evaluated in order to describe the concentration course of all species with sufficient accuracy.     

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.     

Pyrolyse und Gas-Chromatographie der Pyrolyseprodukte von Polymeren Ein experimenteller Vergleich verschiedener Techniken I

Pyrolysis and Gas Chromatography of Pyrolysis Products of Polymers. An Experimental Comparison of Various Techniques I Seven selected characteristic techniques of pyrolysis gas chromatography (pyrography) were examined for their suitability in the investigation of three polymers, namely polymethylmethacrylaete, polystyrol and polyindene. Almost all the techniques tested gave, under suitable conditions, pyrograms in which the respective monomers dominated. However, the yield of monomers varied considerably and was largely impaired dur to the formation of residue and oligomers. The reproducibility of the pyrograms for quantification purpose (e. g. for polymer mixtures) was adequate only in the case of techniques involving pre-reactor. The other techniques too offered valuable contribution towards identification, structure elucidation, and study of pyrolysis reaction.