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EXPERIMENTAL THERMAL AND FLUID SCIENCE, vol.30, no.7, pp.613-620, 2006 (SCI-Expanded)
Experimental work on estimation kinetic parameters for combustion was conducted in a bench-scale fluidised bed (FB: 105 x 200 mm). Combustion medium was obtained by using an electrical heater immersed into the bed. The ratio of heating rate (kJ/ s) to molar flow rate of air (mol/s) regulated by a rheostat so that the heat of combustion (kJ/mol) can be synthetically obtained by an electrical power supply for relevant O-2-feedstock concentration (C-o). O-2-restriction ratio (beta) was defined by the ratio of O-2-feedstock concentration to O-2-air concentration (Co-2-AIR) at prevailing heating rates. Compressed air at further atmospheric pressure (congruent to 102.7 kPa) entered the bed that was alumina particles (250 mu m). Experiments were carried out at different gas flow rates and heating rates. FB was operated with a single charge of (1300 g) particles for obtaining the T/T-o curves, and than C/C-o curves. The mathematical relationships between temperature (T) and conversion ratio (X) were expressed by combining total energy balance and mass balance in FB. Observed surface reaction rate constants (k(s)) was obtained from the combined balances and proposed model was also tested for these kinetic parameters (frequency factor: k(o), activation energy: E-A, and reaction order: n) obtained from air temperature measurements. It was found that the model curves allow a good description of the experimental data. Thus, reaction rate for combustion was sufficiently expressed. (C) 2005 Elsevier Inc. All rights reserved.