Total utilization of waste tire rubber through pyrolysis to obtain oils and CO₂ activation of pyrolysis char

Waste tire rubber (WTR) was pyrolyzed in a fixed bed reactor in the final temperature range of 500-800 C. Pyrolysis oils were analyzed both quantitatively and qualitatively. Pyrolysis chars obtained were activated using CO₂ at a final temperature of 950 C with a final activation time of 1-3 h. In addition, the influence of the acid treatment of pyrolysis char on the physicochemical properties was investigated. In the experiments, the yields of pyrolysis oil and pyrolysis char were 30-38 and about 37 wt.%, respectively. The pyrolysis oils consisted mainly of limonene, aromatic hydrocarbons such as xylene, and some heteroatom-containing compounds, such as benzothiazole and 2,4-dimethylquinoline. The sulfur contents of the pyrolysis oils were 0.85-0.96 wt.%. Most of the sulfur remained in the pyrolysis char. The maximum surface area of the activated char obtained by CO₂ activation was 437 m ²/g. The acid treatment of the pyrolysis char decreased the ash and sulfur contents, which supported the strong potential of the acid-treated char for use in commercial applications.