Behaviour of tyres in fire

Abstract

The increasing numbers of used tyres constitute a serious threat to the natural environment. The progress made in recent years in the management of polymer wastes has meant that used tyres are starting to be perceived as a potential source of valuable raw materials. The objective of this research was to study the burning characteristics of various used tyres. Waste tyres of seven producers have been tested. In order to understand thermal properties, three different assessment methods were used to study the behaviour of the material: (1) determination of ash content, (2) flame propagation test and (3) thermal analysis. The ash content test can be used to analyse how many percentage of the tyre leaves in the form of smoke or gas. The flame propagation test gives information on the duration of the combustion and the degree of smoke generation. Results of thermal analysis (TG/DTG/DTA) show the degree and speed of the mass changes of the different tyre types, the enthalpy change and the temperature of the reactions during heating. By combustion tests, it was modelled how the tyres behave when they are burning in incineration plant. In terms of recycling, those tyres are better, which have low decomposition temperature and smaller residual mass. This also means that maximum combustion heat can be recovered. After burning, the samples showed the greatest difference in loss of mass; however, all are different in flammability, afterglow time and their thermal stability.