A Victorian (Loy Yang) brown coal was pyrolysed in a novel fluidised-bed/fixed-bed reactor under a wide range of experimental conditions. The experimental data indicated that HCN originated mainly from the thermally less stable N-containing structures in the coal. Significant amounts of NH3 could be formed after the feed of coal was stopped as a result of the slow hydrogenation of the thermally more stable N-containing structure by H radicals. In addition to temperature

gas flow rate and coal feed rate could significantly affect the formation of HCN although the yield of NH3 remained almost unchanged

indicating that HCN was not significantly converted to NH3. The effects of coal feed rate on HCN yields were different at the temperature of 973 K and 1073 K.