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Studies of flow in the continuous ultrasonic reactor for optimization of precipitation reactions
Nanoparticles can be defined as a dispersed system in which at least one expansion is below 100 nm. These have to a chemically equivalent continuous material much cheaper optical, electrical, magnetic, mechanical, diffusion and material properties. Nanoparticles are spread in various industrial and scientific fields, eg biotechnology, as catalyst supports, for data or energy storage and microelectronics. With wider use, for example, new so-called "advanced materials", it is necessary to provide sufficient amounts of nanoparticles are available. The low production quantities are currently the reason for the high cost of nanoparticles. As a way to provide inter alia the wet-chemical preparation of nanoparticles to that in stirred tanks brings considerable technical apparatus problems. As an alternative can be seen for mixed-flow reactors and precipitation reactions. These are but especially for precipitation reactions investigated so far and so little on the market and not available in optimized form. The use of ultrasound allows a defined here, externally controllable, intense, localized energy input into the process space. The mixing times, which are achieved by ultrasonic cavitation with the mechanisms of action and vibration are within the range required for the precipitation (<1ms). Must be established with a view of the sonochemistry that the crucial problem is the scale-up of research results obtained in the laboratory reactor to industrial dimensions and flow rates. Occur due to the complex processes in ultrasonic cavitation and resulting in scaling from laboratory to industrial scale adverse effects. The reaction yields are expected in the industrial scale yielding less than. This is the background and motivation for the present project, are pursued by the following objectives:
- Creating a design strategy using modern methodological approaches for a certain class of ultrasonic reactors and hence the
- Evaluation and improvement of the operating performance of ultrasonic precipitation reactors for the production of nanoparticles.
- Demonstration of the automated implementation of a continuous ultrasonic precipitation reactor.
The aim of the synthesis of nanoparticles has to be that the particles are produced as a stable colloid in order to prevent agglomeration of the particles. In the production of nanoparticles by precipitation, the aim is to promote the homogeneous nucleation and to avoid agglomeration. This can be explained by that the highest possible supersaturation a late but intense mixing of the reactant streams reach. To unbalanced flow conditions and also to avoid broad particle size distributions, targeted leadership in power reactors is necessary precipitate.
The overarching goal of this project and technology is the development of reactors for efficient and controlled production of nanoparticles. The concept is based on the wet chemical preparation of nanoparticles in ultrasonic precipitation continuously operated reactors. The design strategies developed here, increase the design safety. Thus, equipment manufacturers or ultrasound specialist with a significantly reduced risk of equipment and systems for precipitation processes using ultrasound and offer design.
A central question in the optimization of precipitation reactors is to evaluate the micro-mixing. The characteristic times of the micro-mixing can be determined using the Villermaux process. The measurement of the sound field is performed with a hydrophone. To characterize the sonochemical reactivity in the homogeneous liquid phase, the Weissler reaction is used. <pstyle="text-align:justify"> This AIF project is a joint project with the Institute of Institute of Mechanical Process Engineering and Processing Technology of the TU Bergakademie Freiberg. At the TU Bergakademie Freiberg is the experimental part of the work on the characterization of hydrodynamic mixing in the process chamber of an ultrasonic reactor using Villermaux reaction, the characterization of the blend by the ultrasonic field and the geometrical spreading in the process chamber, and the optimization of the geometry and operation of the optimized precipitation reactors. At the Technical University of Clausthal, the simulation of flow in the reactor is carried out for the optimization and analysis of micro-mixing.The project is funded by the Industrial Cooperative Research Associations "Otto von Guericke" eV - 15347th AiF
Publications and conferences (*lecturer)
- Ö. Ertunc, N. Özyilmaz, H. Lienhart, K. Beronov, F. Durst:Inhomogeneity of turbulence generated by passive grids, Journal of Fluid Mechanics, in review
- N. Özyilmaz, K. Beronov, A. Delgado: Characterization of the dissipation tensor from DNS of grid-generated turbulence, High Performance Computing in Science and Engineering, Garching/Munich 2007, Springer Verlag, 2008.
- K. Beronov, F. Durst, N. Özyilmaz, P. Lammers: Statistics and intermittency of developed channel flows: a grand challenge in turbulence modeling and simulation, High Performance Computing on Vector Systems, Springer Verlag, 2006.
- N. Özyilmaz*, G. Brenner: Effects of roughness elements on BaSO4 precipitation in T-shaped microchannels. To be presented in Conference on modeling fluid flow 2009, Budapest, Hungary.
- Ö. Ertunc*, N. Özyilmaz, H. Lienhart, F. Durst: Persistence of inhomogeneity of turbulence generated by static grid structures, to be presented in 12th EUROMECH European Turbulence Conferencet Marburg, Germany.
- N. Özyilmaz*, G. Brenner: Numerical Modelling of BaSO4 precipitation. to be presented in ProcessNet Annual Meeting in CFD, Extraction, Mixing, Fulda, Germany, 2009.
- N. Özyilmaz*, G. Brenner:Numerical Modelling of BaSO4 precipitation. to be presented in ProcessNet Annual Meeting in CFD, Extraction, Mixing, Fulda, Germany, 2009.
- N. Özyilmaz, K. Beronov*, A. Delgado:Characterization of the Reynolds stress and dissipation-rate decay and anisotropy from DNS of grid-generated turbulence, GAMM 2008, Bremen, Germany.
- N. Özyilmaz*, K. Beronov, F. Durst:Direct simulation of turbulence generation and transformation in flows obstructed by square grids, Fifth International Symposium on turbulence and shear flow phenomena, Munich, Germany, 2007.
- N. Özyilmaz*, G. Brenner:Ultrasonics Effects in BaSO4 precipitation, To be presented in ProcessNet Annual Meeting Reaction Engineering. Würzburg, 2009.
- K.Beronov*, N. Özyilmaz, F. Durst:Characterization and high-throughput microfluidic applications of an obstructed-channel flow class, Fifth International Symposium on turbulence and shear flow phenomena, Munich, Germany, 2007.