Ignition behaviour of pulp and paper combustible wastes

Ignition behaviour of combustible wastes from the pulp and paper industry was studied in a modified thermogravimetric furnace. Criteria for ignition and the ignition mechanism were developed. The ignition of combustible wastes was predominantly homogeneous. The influence of different factors, such as particle size, sample type, heating rate and oxygen concentration, was studied. In general, no monotonic relationship between ignition temperature and particle size was observed. Different types of sample had different ignition temperatures (ranging from 203 to 227°C). The ignition temperature increased with heating rate but decreased with oxygen concentration. The combustible waste samples were collected and morphologically analysed at different stages of the heating process. No significant differences in morphology were observed just before and after ignition. The results obtained are useful in identifying the region for injection of combustible wastes into industrial combustors (e.g. boilers or fluidized beds).