Thermo-chemical conversion of scrap tire waste to produce gasoline fuel

Catalytic hydropyrolysis (CHP) of scrap tire was investigated for production of gasoline fuel. Effects of CHP process variables such as catalysts type ((activated carbon, AC), Ir/C, Rh/C, Pt/C, Ru/C, and Pd/C), temperature (200-450 °C), time (30-120 min), catalyst loading (0-40 wt%), and hydrogen pressure (0.1-12 MPa) on the CHP products distribution and properties of the hydropyrolysis oil (HPO) were examined. Ru/C was identified as the most suitable catalyst in terms of the HPO quality and the catalytic effect predominantly came from the noble metal. Temperature was the most influential factor affecting the yield and quality of the HPO and followed by the order of catalyst loading > H₂ pressure > time. Higher temperature, time, and catalyst loading would decrease the yield of HPO and increase the yield of gaseous product whereas contrary results were observed with increasing the H₂ pressure. With added noble metals, the hydrodenitrogenation, hydroSization, and hydrodeoxygenation reactions of the HPO were promoted and greatly lowered N, O, and S contents of the HPO with increasing the temperature, time, catalyst loading, and H₂ pressure. The lowest N, O, and S contents of 0.02, 0.41 and 0.41 wt% of HPO were achieved at 430 °C, 60 min, 10 wt% Ru/C, and 12 MPa H₂. The higher-heating value of the HPOs varied between 44 and 46 MJ/kg depending on the reaction conditions. More than half of the energy of the ST was converted into the HPO. The HPO mainly consisted of saturated and unsaturated hydrocarbons one to five benzene derivatives. The distillate fraction between 35 and 250 °C of the HPO is more than 80 wt%. Thus, we view that CHP is an alternative way to produce high quality hydro-carbon fuel from scrap tire.