Optimal production of waste tire pyrolysis oil and recovery of high value-added D-limonene in a conical spouted bed reactor

Abstract

Owing to the rapid increase in the global automobile demand, the disposal of waste tires has become a severe problem. Most waste tires are reclaimed and incinerated; exhaust gas and ash from incineration comprise harmful substances and dust. Therefore, in this study, fast pyrolysis technology was investigated to overcome the limitations of traditional methods and stably treat waste tires. Fast pyrolysis experiments were performed in a conical spouted bed reactor (CSBR) to investigate the optimal pyrolysis conditions for waste tires with respect to the reaction parameters: reaction temperature, superficial gas velocity, and feeding rate. The characteristics of waste tire pyrolysis oil (WTPO), which is the main target material for fast pyrolysis, were analyzed through moisture, higher heating value (HHV), and viscosity. The optimal pyrolysis conditions were a reaction temperature of 450 °C, superficial gas velocity of 1.1, and feeding rate of 1 kg/h. Under these conditions, the WTPO yield was 66.9 wt% and energy efficiency was 82.1%. Furthermore, to recover high value-added D-limonene, the WTPO produced under optimal conditions was distilled, and gas chromatography mass spectrometry (GC-MS) analysis was performed to evaluate the product. According to the distillation experiment, the recovery efficiency of D-limonene was highest at 4 h.