Recycling

Biography

Biography: Peter Tumwet Cherop

Abstract

The global consumption of tyres has increased over the years. However a very small percentage of the total mass of waste tyres can be recycled or reused for other applications. Land-filling has been considered an option to address the problem of scrap tyres. However, large space is required and the reusable resources are wasted. This therefore has led to environmental and economic problem of the disposal of the huge mass of scrap tyres. Scrap tyre pyrolysis, which is basically the thermal decomposition in an oxygen-free atmosphere, can be potentially involved with the recovery of both energy and material. Thermogravimetric analysis (TGA) and derivative thermogravimetry (DTG) are the techniques commonly used to measure the mass loss kinetics associated with the vaporisation of materials during pyrolysis. Understanding the kinetics of pyrolysis is important in the optimisation design of industrial scale scrap tyre recycling. The purpose of this study was to determine the thermal degradation kinetics of scrap tyres by TGA/DTG, and to compare the apparent activation energy (Ea) and the pre-exponential factor (A) values calculated using   the Arrhenius, Coats–Redfern and Flynn-Wall-Ozawa methods. The experiments were conducted under a nitrogen atmosphere and a temperature range of 20°C to 600°C at different heating rates. The thermal decomposition started at an average temperature of 240°C and was complete at 480°C for the four heating rates. Results indicate that higher heating rates lead to greater mass losses. The average mass loss was 63.64 wt. %. The mean E_a values obtained by the different model free methods used were similar. However there was a variation in the pre-exponential factor values.