Microwave fast pyrolysis of waste tires: Effect of microwave power on product composition and quality

Abstract

Pyrolysis of waste tires can not only solve environmental problems but also recycle waste materials. However, the poor thermal conductivity and the significant energy consumption of the conventional thermal decomposition method severely hinders the implementation of this technology. Microwave pyrolysis is an appealing approach to recycling waste tires since the waste tires contain a high amount of metal oxides additives and carbon black, which can quickly absorb microwave radiation and convert it into heat. During the pyrolysis process, the generated gaseous, liquid, and solid products were all collected separately and characterized. The major components of the pyrolysis gases were H2, CH4, and C2H4. The liquid products were complex mixtures of organic compounds with large proportions of aromatics (BTX) and limonene. The solid residues have high contents of amorphous carbon and inorganic compounds (SiO2, SO3 and ZnO) formed from additives employed in tire formulation. It is worth noting that the use of microwave pyrolysis to decompose waste tires can greatly shorten the pyrolysis time, inducing the pyrolysis reaction completed within 20 min.