Catalytic and noncatalytic fast pyrolysis of waste tires to produce high-value monocyclic aromatic hydrocarbons

Abstract In this work, catalytic and noncatalytic fast pyrolysis of waste tires were studied in an analytical pyrolyzer coupled with gas chromatography-time-of-flight mass spectrometry to obtain valuable monocyclic aromatic hydrocarbons (MAHs), especially benzene, toluene, ethylbenzene, xylene etc. (BTEX). The various influencing factors such as the heating rate (10−20000 °C/s), atmosphere (He, H2, N2, CH4, O2), temperature (500−800 °C), and time (5−30 s) were explored. The heating rate and temperature had the greatest influence on the distribution of pyrolysis products, where 40.91 % MAHs were obtained at 500 °C/s and 750 °C in helium atmosphere. In the process of catalytic fast pyrolysis, the nine zeolite catalysts were investigated. The Hβ catalyst is conducive to the formation of MAHs (up to 53.09 %), while the content of BTEX was only 9.05 %. The MCM-41Q catalyst is beneficial to the formation of BTEX (22.35 %), as the content of MAHs was 46.09 %.