Brandner J.J.,Institute for Micro Process Engineering
Applied Thermal Engineering | Year: 2013
Process intensification by miniaturization is a common task for several fields of technology. Starting from manufacturing of electronic devices, miniaturization with the accompanying opportunities and problems gained also interest in chemistry and chemical process engineering. While the integration of enhanced functions, e.g. integrated sensors and actuators, is still under consideration, miniaturization itself has been realized in all material classes, namely metals, ceramics and polymers. First devices have been manufactured by scaling down macro-scale devices. However, manufacturing tolerances, material properties and design show much larger influence to the process than in macro scale. Many of the devices generated alike the macro ones work properly, but possibly could be optimized to a certain extend by adjusting the design and manufacturing tolerances to the special demands of miniaturization. Thus, some considerations on the design and production of devices for micro process engineering should be made to provide devices which show reproducible and controllable process behavior. The aim of the following publication is to show the importance of considerations in manufacturing tolerances and dimensions as well as design of microstructures to avoid negative influences and optimize the process characteristics of miniaturized devices. Some examples will be shown to explain the considerations presented here. © 2013 Elsevier Ltd. All rights reserved.
Pfrengle A.,Institute for Materials Research III |
Pfrengle A.,Albert Ludwigs University of Freiburg |
Binder J.R.,Institute for Materials Research III |
Ritzhaupt-Kleissl H.-J.,Institute for Materials Research III |
And 4 more authors.
International Journal of Applied Ceramic Technology | Year: 2010
Based on previous work, the material properties of zirconium disilicide containing net-shape ceramic compositions are adjusted to minimize the edge flaking that occurs during micromilling of the green bodies. The material compositions (besides ZrSi 2, also containing ZrO 2, Al 2O 3, MgO, SiO 2, and a polysorbate) are granulated and axially dry pressed to pellets, which are wet milled with a 0.5-mm-diameter tool. The structure's edge flaking is quantitatively determined and compared with previous results. The mechanical properties of the green and sintered bodies are also characterized. The strengths of the green bodies depend on their composition and treatment. Additionally, a correlation between the Weibull moduli of the green compacts and the moduli of the sintered parts is shown. For the sintered ceramics, Weibull strengths of up to 344 MPa can be achieved. It is also shown that the dimensional accuracy of the net-shape material is maintained. © 2009 The American Ceramic Society.
Zschieschang E.,Karlsruhe Institute of Technology |
Pfeifer P.,Institute for Micro Process Engineering |
Schebek L.,Karlsruhe Institute of Technology
Leveraging Technology for a Sustainable World - Proceedings of the 19th CIRP Conference on Life Cycle Engineering | Year: 2012
Resource efficiency has become increasingly important in new technology development, such as micro-system and microprocess engineering, due to three major trends: shorter development times, high production volume per time, and use of rare earth metals. It is therefore imperative to optimize the design of these technologies with respect to their environmental impact during their whole life cycle in an early stage of technology development. The question arises, how can technology development be combined with Life Cycle Assessment for new technologies in early stage R&D? Our study offers an answer to this question, using micro-process technology as an example of a new technology, which is said to allow step changes in chemicals production and uses totally different approaches compared to conventional engineering.
Anurjew E.,Institute for Micro Process Engineering |
Hansjosten E.,Institute for Micro Process Engineering |
Maikowske S.,Institute for Micro Process Engineering |
Schygulla U.,Institute for Micro Process Engineering |
Brandner J.J.,Institute for Micro Process Engineering
Applied Thermal Engineering | Year: 2011
Evaporation of liquids is of major interest for many fields in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of superheated steam is mandatory for numerous processes. Generally, this is performed by the use of classical pool boiling and evaporation process equipment, providing relatively limited performance, or by other systems like falling-film or membrane evaporators. Due to the advantages of microstructure devices especially in chemical process engineering the interest in microstructure evaporators and steam generators has increased through the last decade. In this publication different microstructure devices used for evaporation and generation of steam are described. Starting with simple liquid-heated devices, different types of electrically powered devices containing micro channels as well as non-channel microstructures will be shown. While evaporation of liquids in crossflow and counterflow or co-current flow micro-channel devices is possible, it is, in many cases, not possible to obtain superheated steam due to certain boundary conditions. Thus, a new design was proposed to obtain complete evaporation and superheating of the generated steam. © 2010 Elsevier Ltd. All rights reserved.