Composition, Combustion and Emission Characteristics of Distillation Fractions of Pyrolysis Oil of Waste Heavy-Duty Tires

The steam pyrolysis of end-of-life waste tires is viable technology for obtaining pyrolysis oil, which could be used as fuel. The purpose of current study is determining emission and combustion characteristics of different waste tires pyrolysis oil fractions as well as their chemical properties and composition. The pyrolysis oil was obtained by steam pyrolysis of waste heavy-duty vehicle tires at 500 degrees C, and distilled into 6 fractions with boiling temperatures varied in range of 60-448 degrees C. The higher boiling temperature fraction consisted of hydrocarbons with higher molecular weight. The maximal sulfur content was observed for 180-250 degrees C fraction. Ignition delay times of studied samples were varied in range of 0.58-5.38 s, flaming combustion times-2.16-4.28 s, total combustion times-2.73- 8.41 s. Both ignition delay and total combustion times had been monotonously increasing with boiling temperature of fraction, while flaming combustion times were increasing up to 300-350 degrees C fraction. Combustion behavior of all samples indicated significant contribution of homogeneous gas-phase reactions. Emission characteristics of pyrolysis oil and its individual fractions were majorly determined by their reactivity and composition. Higher CO, CO2 and NO emissions were observed for fractions with higher boiling temperatures, while SO2 emissions were independent of boiling temperature and were connected to sulfur content. Maximal sulfur oxide emissions were observed for fraction 180-250 degrees C. The NO emissions of initial pyrolysis oil sample were higher than for any of its fraction, while SO2-lower (with < 180 degrees C fraction as exception) indicating negative and positive synergistic effects, respectively.