Importance of Volatile-Char Interactions on Char Reactivity During the Gasification of Victorian Brown Coal
Our recent studies have found that volatile-char interactions are one of the most important aspects of the behaviour of coal during gasification. This is especially true for a fluidised-bed gasifier. This study aims to further investigate the effects of volatile-char interactions on the reactivity of char during the gasification of Victorian brown coal at 800°C. A novel fluidised-bed/fixed-bed reactor allowing the control of the extent of volatile-char interactions has been used to carry out gasification experiments in steam and low concentrations of O2¬. Our experimental results indicate that volatile-char interactions greatly affect the char structure and the retention of coal-Na in char, thus affecting the char reactivity. The volatile-char interactions greatly inhibited the reactivity of char in steam. Our experimental results will be discussed in terms of reaction mechanisms between char and radicals in the volatiles.