Abstract
Almost all of the natural rubber produced nowadays is used for production of tires. Due to the longevity of rubber products, the disposal of waste tires has caused many environmental and hygiene concerns. Since there is an enormous amount of waste tire generated globally each year, reuse and recycling of the waste tires are becoming an important environmental issue. Pyrolysis is a recycling method for fully decomposing waste tires into various reusable substances. In the present contribution, catalytic cracking of waste passenger tires was investigated using ZrO2/SO42- as catalyst in a semi-batch reactor at 500°C under inert atmosphere. Gas products were found to be composed of methane, ethylene, ethane, propylene, propane, C4-, C5-, C6-, C7-, and C8- hydrocarbons. The volume of liquid yield increased while gas and solid residue yield decreased with increasing loaded sulfate of up to 8%. Four different catalysts to tire ratios were tested (i.e. 0.1:1, 0.25:1, 0.5:1, and 1.0:1 w/w) for a fixed loaded sulfate of 4%. At 25% catalytic loading, the relative amount of light fractions was found to be the highest, which was found to be the optimal condition for pyrolytic recycling of the model tires.
