Optimization of pyrolysis conditions of scrap tires under inert gas atmosphere

A pyrolysis system was designed for the production of activated carbon and other products from scrap tires. The system allows work under inert atmosphere (N-2 gas). The pyrolysis experiments were carried out in a fixed-bed batch reactor of (1.25 m length and 0.03 m o.d.) which was heated by an electric furnace. The feed material used was scrap tires supplied from General Company Rubber Industry, Najaf. The experiments were carried out to evaluate the optimum conditions for the production of pyrolytic carbon and oil. The following variables were studied: pyrolysis temperature (400-460degreesC), nitrogen flow rate (0.2-0.5 m(3) h(-1)) and particle size (2-20 mm). The optimum conditions were 430degreesC, 0.35 m 3 h(-1) and 10 turn, respectively. At these conditions, the yield of carbon black and pyrolytic oil were, 32.5 and 51.0 wt.%, respectively. The effect of experimental variables on the yields of active carbon and pyrolytic oil was studied using the Box-Wilson technique of experimental design and useful relationships could be attained. (C) 2004 Elsevier B.V. All rights reserved.