Steam gasification and combustion kinetics of gingko nut shell in a thermo balance reactor

Abstract

Pyrolysis kinetics of a gingko nut shell in a thermo gravimetric analyzer (TGA) and the steam gasification and combustion kinetics of chars from gingko nut shell in a thermobalance reactor have been determined. The effects of the reaction temperature (350 °C – 950 °C) and steam partial pressure (0.4 - 0.8 atm.) on the gasification kinetics and that of oxygen partial pressure (0.4 - 0.8 atm.) on the combustion kinetics have been determined in a thermobalance reactor. The activation energy and the pre-exponential factor were determined from the Arrhenius plot based on the shrinking core model. In the steam gasification reaction, the activation energy and the pre-exponential factor are found to be 40.8 kJ mol -1 at 1.7 s -1 atm. -1 , respectively. The reaction order is found to be 0.32 with respect to water partial pressure at 750 °C. In the combustion reaction, the activation energies and pre-exponential factors are found to be 92.8 kJmol -1 at 136.8 s -1 atm -1 and 9.2 kJmol -1 at 0.012 s -1 atm -1 in the reaction control and the pore-diffusion control regimes, respectively.