Akademik Veri Yönetim Sistemi
FUEL PROCESSING TECHNOLOGY, cilt.126, ss.441-452, 2014 (SCI-Expanded)
Coal particle separation in a classifier after the pulverization process in power plants (PP) is very important to
obtain the desired level of coal fineness while reducing unburned carbon losses and slagging potential. In this
study, flow inside of the coal mill classifier of Soma B PP suffering from low boiler efficiency due to high unburned
carbon loss was numerically analyzed with respect to its initial flow measurements and isokinetic coal samples at
the exit of the classifier as a base case. In the numerical analyses, a Eulerian/Lagrangian approach and a Reynolds
stress turbulence model (RSTM) were applied. To increase coal separation efficiency, four different designs were
numerically analyzed and the results were compared to the results of the base case by accounting for the total
mass flow rate to the burners and coal size distribution at the outlet of the classifier. Among them design D-21
was chosen and applied to the PP mill classifier. Finally, this design was tested in a PP with different inner
plate adjustments, and there was good agreement between the numerical and experimental results with
a maximum difference of 2.5% for the individual coal size distributions and a cumulative maximum difference
of 5% for the total coal size distributions. The assumption of a decreasing regrind outlet of coal flow rate by
plate adjustment in the classifier for D-21 appears to be sufficient to increase total coal flow rate to the burners.
In the tests, operating the mill at lower load conditions resulted in a finer coal size distribution at the outlet.