Application of CDF modelling to mill classifier design

Abstract:

<p>This document is a report that summarises the findings of the DTI Cleaner Coal Technology R and D Programme Project 217 'Application of CFD Modelling to Mill Classifier Design'. </p> <p>In order to reduce the carbon in ash (CIA) levels arising from the application of advanced low NOX technologies, it is necessary to improve the quality and consistency of the coal milling process. In many low NOX retrofit applications, mill upgrades, including classifier upgrades, are required to achieve the improved milling performance. Unfortunately, plant space constraints often make it impossible to install classifiers of ideal geometries and the performance of non-ideal geometries is difficult to predict using existing design methods. In addition, low quality coals are increasingly being used, alone or in blends, to reduce plant operating costs. The grinding and classification behaviour of low quality coals and their blends has been found to differ from that of UK and world-traded bituminous coals. Consequently, classifier design rules that have been derived from the extensive experience of milling bituminous coals are less reliable when applied to low quality coals. There is a clear requirement to improve and extend the range of applicability of classifier design methods so that they may be used to design classifiers of non-ideal geometries and for coals outside the conventional range of experience.</p> This report is divided into the following sections: <ol> <li>Introduction</li> <li>Classifier Design</li> <li>Review of E Mill Classifier Process Data and Design Rules</li> <li>Physical Model Testing</li> <li>CFD Simulation of Physical Model</li> <li>Plant Trials</li> <li>CFD Simulation of E Mill Classifiers</li> <li>Development of Improved Design Rules</li> <li>CFD Simulation of Primary Classification</li> <li>Conclusions</li> <li>Recommendations for Further Work</li> <li>Acknowledgements</li> </ol>

Author(s):

Foster, DJ, Livingston, WR, Wells,J, Williamson, J, Gibb, WH & Bailey, D