Heating rate effects on pyrolytic vapors from scrap truck tires

- Pyrolysis of truck tires and study of the produced pyrolytic vapors were performed.
- Qualitative and quantitative analysis for both gas and pyrolytic oils were carried.
- The response factor method is used for GC-FID calibration.
- The higher heating rates promote the gas production at the expense of oils.
- Pyrolytic oils are mainly composed of aromatic and olefin products.

Powder of scrap truck tire was pyrolysed in a fixed bed reactor equipped with a water-cooled liquid recovery system and a gas sampling valve. A sampling system was set up and the quantitative and qualitative analyses of pyrolytic vapors were performed for heating rates (HR) ranging from 5 to 25 °C min−1. HR which practically has no influence on the quality and yield of char (38 wt%), has a significant effect on the pyrolytic vapors, especially on the cracking reactions of heavy vapors. By increasing HR from 5 to 25 °C min−1, the gas yield increases from 7.24 to 18.04 wt% at the expense of oil yield. The high heating rates favor production of CH4 and disadvantage production of C4H8. In addition, heating rates between 10 and 15 °C min−1 minimize the H2, CO and CO2 concentrations and maximize the C2H6, C3H6, C4H6 and H2S concentrations. Its lower heating value is between 47 and 56 MJ Nm−3. As regards the produced oils, they consist mainly of aromatic products whose higher heating value is about 40 MJ kg−1. Regardless of heating rates, around 97.15% of the energy contained in raw material (tire) is found in the three pyrolysis products. The sulfured organic compounds appear in forms of C7H5NS, C15H16O3S and C16H14O2N2S.