Determination of the intrinsic reactivities for carbon dioxide gasification of rice husk chars through using random pore model

Rice husk is abundantly available and environmentally friendly, and char-CO2 gasification is of great importance for the biomass gasification process. The intrinsic reaction rates of carbon dioxide gasification with rice husk chars derived from different pyrolysis temperatures were investigated in this study by conducting thermogravimetric analysis (TGA) measurements. The effects of gasification temperature and reactant partial pressure on the char-CO2 gasification were investigated and the random pore model (RPM) was used to determine the intrinsic kinetic parameters based on the experimental data. The results obtained from this study show that the activation energy, reaction order and pre-exponential factor varied in the ranges of 226.65-232.28 kJ/mol, 0.288-0.346 and 2.38 x 10(5)-2.82 x 10(5) 1/s Pa-n for the rice husk chars pyrolyzed at 700-900 degrees C, respectively. All the determination coefficients between the RPM predictions and experimental results were higher than 0.906, indicating the RPM is reliable for determining and evaluating the intrinsic reactivities of rice husk chars. (C) 2016 Elsevier Ltd. All rights reserved.