Roles of ruthenium on catalytic pyrolysis of waste tire and the changes of its activity upon the rate of calcination

The catalytic pyrolysis of waste tire with Ru/SBA-1 catalysts was studied. The roles of ruthenium were elucidated since the support, a pure silica SBA-1 synthesized via silatrane route, was proven to be catalytically inactive and its structure retained after pyrolysis. Ruthenium clusters increased the yield of gaseous products, approximately 2 times as compared to thermal pyrolysis, at the expense of the liquid yield. They also decreased poly- and polar-aromatics and consequently produced lighter oil. The heating rates (1 degrees C/min, 5 degrees C/min, and 10 degrees C/min) during calcination were found to strongly influence the activity of the Ru/SBA-1 catalysts. The catalyst calcined with a heating rate of 5 degrees C/min exhibited the highest activity on poly- and polar-aromatics reduction and light oil production. The highest activity of this catalyst was attributed to its smallest mean ruthenium particle size and its highest sulfur tolerance. (C) 2010 Elsevier B.V. All rights reserved.