Thermal And Catalytic Pyrolysis Of Waste Tires

Nowadays, waste tires have not only caused serious environmental problems but also a huge waste of resources. Among the different alternatives for tire recycling, such as retreating, reclaiming, incineration, grinding, biodegradation, etc., pyrolysis has been proposed as a viable recycling technology. However, owing to technical problems as well as economic and legal factors, the pyrolysis processes of tires have not been cost-effective up to now.Large-scale tertiary recycling of waste tires will require efficient catalytic cracking methods. Therefore, the detailed knowledge of thermal and catalytic cracking mechanism is necessary. In this paper we systematically studied the behaviors of thermal and catalytic degradation of waste tires and the main rubber components of tires, including natural rubber (NR), polybutadiene rubber (BR) and styrene-butadiene rubber (SBR), in a batch reactor with stirring. The aims are to improve their catalytic degradation ability and at the same time control potential harmful products produced during catalytic degradation. Furthermore, it will be expected to provide a theoretical basis for recycling waste tires.First, catalytic copyrolysis of waste tires over ZSM-5 zeolite with lubricant base oil (LBO) was investigated. By combining with LBO, the ZSM-5 catalyzed pyrolysis system of tires has a sharply enhanced degradation rate. Compared to the pyrolysis without LBO, the liquid yield is increased from 33.6 % to 48.0 %, while the gas and the residue yields are decreased. In the pyrolysis oils, the content of heavy components is decreased, and the content of light oils (n-C≤12) is increased from...