Comparison of Kinetic Models for Carbon Dioxide and Steam Gasification of Rice Husk Char

This study reports carbon conversion rate calculated from the online gas analysis obtained from rice husks char gasification by using carbon dioxide and steam as reactive gases. Rice husks char is produced by the pyrolysis of rice husks in a muffle furnace at 450 °C during 45 min. The gasification tests are carried out at several temperatures 900, 950 and 1000 °C by using carbon dioxide and steam under isothermal conditions. The volume reaction model (VRM), shrinking core model (SCM) and random pore model (RPM) are studied to interpret obtained experimental data. Kinetic parameters such as activation energy (E) and pre-exponential factors (A) are determined from gas-analysis data by using Arrhenius equation. From results confrontation, between experimental data and obtained results from used models, it is found that RPM agrees better with experimental data than the other two models. We also obtained an activation energy of 165.8 kJ/mol and pre-exponential factor of 2595.4 s−1 for Ψ equal to 3.8 for carbon dioxide gasification and, respectively, 152.9 kJ/mol and 3473.4 s−1 from Ψ = 2.16 for steam gasification.