Kinetics and exergy analysis of pyro-gas from residual tyres

Abstract

About1.5 billion tyres are manufactured every year and enormous quantity of the tyres end up in trash. Waste rubber tyres possess calorific value around 39- 42 MJkg-1which makes it an attractive choice for pyrolysis process. The aim of the present work is to convert residual tyres into energy reach pyro-gas. A single column fixed bed batch pyrolyzer was designed pyrolysis of residual tyres. The residual tyres were ground into fine powder. The characterization of powdered residual tyres was performed with elemental analyser to determine the total carbon, hydrogen, nitrogen and sulphur. Thermo Gravimetric Analysis of the residual tyres was conducted at different heating rates viz., 5 °C min-1, 10 °C min-1, 15 °C min-1 to elucidate the thermal degradation profile. The thermal cracking of a residual tyres was conducted at temperature range of 450 °C to 550 °C with increment of 50 °C. Pyro-gas was measured individually for each trail and the exergy was determined using thermodynamic laws. Four different model-free methods were employed to estimate the kinetic parameter such as activation energy and order of the reaction. The average activation energy from Friedman model was evaluated to be 127.35 kJ mol-1. A maximum of 52.11% of Pyro-oil was reported at 550 °C. The maximum energy and exergy were 5.49 MJ kg-1 and 4.92 MJ kg-1 respectively.