Low Temperature Fluidized Bed Coal Drying: Experiment, Analysis and Simulation

T Dejahang
2015
Drying kinetic of Canadian lignite was studied in a pilot scale fluidized bed dryer using low temperature air (T≤70 ˚C). Minimum fluidization velocity was calculated and applied to the experiment. Samples showed poor fluidization due to large particle size (1-2.8 mm) and density (1400 kg/m 3 ). The effect of drying parameters was studied experimentally. Gas temperature showed a great effect on increasing drying rate in the constant drying period and low effect in the falling rate period.
more » ... rate period. Increasing gas velocity proved to be poorly effective in drying due to low fluidization. Smaller particle size led to higher drying rate. Drying curves were curve fitted to available kinetic models in the literature and logarithmic model showed the best fit. Diffusion coefficient, activation energy and pre-exponential factor of lignite drying were calculated and showed good agreement with reported values in the literature. CFD analysis was carried out in Ansys-Fluent 14.0 and tuning the solid-fluid exchange coefficient, the constant rate drying period was successfully simulated. Spontaneous combustion kinetics of Canadian lignite was studied experimentally and analytically. iii
doi:10.7939/r3k931d1n fatcat:ftso3yxhlrgf7omol46ox5suga