Experimental Investigation of Thermal Characteristics of Kiwira Coal Waste with Rice Husk Blends for Gasification

Abstract

Eminent depletion of fossil fuels and environmental pollution are the key forces driving the implementation cofiring of fossil fuels and biomass. Cogasification as a technology is known to have advantages of low cost, high energy recovery, and environmental friendliness. The performance/efficiency of this energy recovery process substantially depends on thermal properties of the fuel. This paper presents experimental study of thermal behavior of Kiwira coal waste/rice husks blends. Compositions of 0, 20, 40, 60, 80, and 100% weight percentage rice husk were studied using thermogravimetric analyzer at the heating rate of 10 K/min to 1273 K. Specifically, degradation rate, conversion rate, and kinetic parameters have been studied. Thermal stability of coal waste was found to be higher than that of rice husks. In addition, thermal stability of coal waste/rice husk blend was found to decrease with an increase of rice husks. In contrast, both the degradation and devolatilization rates increased with the amount of rice husk. On the other hand, the activation energy dramatically reduced from 131 kJ/mol at 0% rice husks to 75 kJ/mol at 100% rice husks. The reduction of activation energy is advantageous as it can be used to design efficient performance and cost effective cogasification process.

Pyrolysis and char oxidation characteristics of oil shales and coal in a thermogravimetric analyzer

“…However, the apparent activation energy and preexponential factor for oxidation of coal char are higher than those of EOS char due to a high fixed carbon content more than four times of that of EOS. [35] Although comparison with the values from literature is difficult because of different equipment and experiment parameters used, the activation energy of EOS char oxidation is quite well in agreement with the values of Turkish oil shale oxidation under air atmosphere. [34,36] The predicted results using the optimized parameters according to one-and multi-step models assuming the n th order reaction function are compared with the experimental data in Figures 2, 4-6 for pyrolysis, and Figures 3 and 7 for char oxidation, respectively.…”

Studying the influence of the intensity of mechanochemical activation on the process of steam conversion of coal

“…Paper [15] reported experimental study into a thermal behavior of blends of coal waste. The authors examined the speed of degradation, conversion rate and kinetic parameters.…”