Thermogravimetric Studies on the Global Kinetics of Carbon Gasification in Nitrous Oxide

The global kinetics of the carbon gasification in N2O were determined with a thermogravimetric system. The carbon was a phenol−formaldehyde resin char of low impurity levels, and the burn-off range of the carbon in this study was 0−45%. The temperature range studied was 673−923 K, and the partial pressure of N2O was varied from 10.1 to 101 kPa. The kinetics can be divided into two temperature regimes. The low-temperature regime (748 K) is exhibited by an activation energy, which is also an increasing function of the burn-off level, ranging from 170 to 230 kJ/mol. The reaction order with respect to the N2O partial pressure is not constant. The rate of gasification increases with the N2O pressure to a maximum and then begins to decrease with a further increase of the pressure.