Effects of pyrolysis temperature and Pt-loaded catalysts on polar-aromatic content in tire-derived oil

This study investigates the influences of pyrolysis temperatures and Pt-supported catalysts on polar-aromatic content in the oils obtained from pyrolysis of waste tire. These polar-aromatic compounds are mostly the sulfur-containing aromatics since oxygen is prohibited in pyrolysis. The experimental results indicated that pyrolysis temperatures strongly affected the polar-aromatic content in the derived oils. Namely, the increase in pyrolysis temperature in the tested range produced not only a higher amount of polar-aromatics but also heavier polar-aromatic compounds. All studied catalysts decreased the polar-aromatic content in the oils drastically. In addition, it was found that the introduction of the studied catalyst also led to the production of lighter polar-aromatic compounds with respect to that produced from thermal pyrolysis. Comparing the two acid catalysts, HBETA exhibited higher activity for polar-aromatic reduction as compared to HMOR, which was ascribed to its higher medium and strong acid site density, smaller particle size and 3D-structure. The Pt supported on HMOR and HBETA catalysts showed better polar-aromatic reduction activity than their corresponding acid catalysts. And, a slightly higher catalytic activity was observed over Pt/HBETA than Pt/HMOR, which was mainly due to the higher Pt dispersion of Pt/HBETA catalyst. (C) 2009 Elsevier B.V. All rights reserved.