Flow and energy optimisation
of electrostatic precipitators |
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The Danish Maritime Institute (DMI) and FLS miljø a/s have carried out a project using STAR-CD with the aim of developing a generic tool for the design of flow-conditioning devices applied at inlets of electrostatic precipitators. The main objective of the project was to reduce the energy consumption and to obtain a better industrial process by developing and applying modern flow-calculation methods to the design of new and reconstruction of existing flue-gas cleaning plants. Through application of the method, optimisation of the gas distribution in electrostatic precipitators has been achieved resulting in:
The newly developed model is based on Computational Fluid Dynamics (CFD) with which the three-dimensional flow in an electrostatic precipitator can be calculated and the effect of flow optimisation devices such as screens can be predicted. The implemented model is designed specially for FLS miljø screens; however, the basic model is generic and can be applied with different input data for calculation of the flow field in other designs and applications. Accurate modelling of the entire screen geometry with
CFD would demand more computational power than today’s
computers can provide. Instead, the effect of screens on
the flow was calculated through modelling of the resulting
forces acting on the flow due to the screens, reducing
the computational effort significantly. |
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A series of physical model scale tests involving flow through screen elements was carried out, partly to generate input data for the model, partly to verify the model. These tests yielded detailed information about the effect of specific screens applied by FLS miljø. On the basis of the model tests, it was possible to verify equivalent numerical calculations of flow through screen elements, so that input data could be established by numerical means. A detailed database containing the forces acting on the flow due to the screens was set up and used as input data in the model. The model was used to predict the gas distribution in FLS miljø electrostatic precipitators, and comparisons with experimental scale model data as well as full-scale measurements were carried out. Satisfactory agreement between experimental data and the model predictions was found. The project has shown that it is possible and advantageous to apply numerical calculations for dimensioning flow-conditioning devices. The developed model is flexible and allows a fast evaluation of different screen configurations leading to easier design and optimisation. For further information, please write to the Head of Department, Henning Hassing hh@dmi-online.dk
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