3 results
Now showing1 - 3 of 3
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Determination of Kinetics for Reactive Bubbly Flows Using SuperFocus Mixers(Springer, 2021-07-30); ; ; ; For the well-defined investigation of reactive bubbly flows it is crucial to know the kinetics of the chemical reaction steps as detailed as possible which means that the hindrance due to mixing should be minimized (intrinsic kinetics). This is especially difficult for fast chemical reactions that are addressed in this book. Therefore, to distinguish between convective mixing and diffusion a tool should be used that enables an optical access to visualize and detect the instant mixing on a microscale and the comparison with numerical simulations. Furthermore, this tool should be easy to handle for chemical engineers and inexpensive. A SuperFocus mixer in a continuous-flow setup is used for this purpose, in which two mixable liquid streams are mixed, with the gas phase dissolved in one of the streams. The results are compared with a classical stopped-flow apparatus. Because chemical reactions are generally following a complex reaction network with many reaction steps and intermediates that are mostly difficult to detect, the measurement of the formation of the relevant products and by-products is a difficult task by its own. Spectroscopic methods including absorption or fluorescence measurements are used here to detect the formation of the relevant products and to determine the gross kinetics for the relevant reaction steps. Finally, the experimental results are used to adapt direct numerical simulations for an estimation of the corresponding diffusion coefficients and reaction constants.Publicationtype: Book Part60 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Reaction systems for bubbly flows(Wiley-VCH, 2018-05-24); ; ; ; Reactive bubbly flows are at the heart of multiphase flows which are a major topic in chemical engineering since many bulk chemicals are produced in bubbly flows. However, the factors determining product yield and selectivity are often subject of complicated mass transfer effects. Herein, we describe the latest developments in the detection of mass transfer effects in bubbly flows. Coordination chemistry has given new impulses to this topic due to the possibility to synthesise tailored complex systems for the detection of O2 and NO with various time- and space-resolved techniques. For each chemical reaction system, a background section is summarised to allow the reader to get an overview of the different systems.Publicationtype: Journal ArticleScopus© Citations 19 412 564 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Test system for the investigation of reactive taylor bubbles(Wiley-VCH, 2017-07-06); ; ; ; Detailed analysis of reactive multiphase flows is still challenging due to the complex linked transport processes. Until now, there is no reliable and reproducible experimental method for gas-liquid flows, which enables the local measurement of dissolved species concentrations of educts, products, and side products at well-defined and reproducible hydrodynamic conditions. A vertically arranged glass channel is used to capture gas bubbles with well-defined wake structures. The hydrodynamic conditions in the wake can be predicted by dimensionless numbers and adapted for most industrially relevant systems. An experimental apparatus is presented for the investigation of the interdependency between hydrodynamics, mass transfer, and chemical reaction. The applicability of the setup is demonstrated with a chemical test system that shows a strong color shift from colorless to blue when the gas-liquid reaction takes place.Publicationtype: Journal Article99