Recovery of waste tyres by pyrolysis in a fixed bed reactor for liquid fuel production: effects of pyrolysis conditions on oil yield

One of the major enviromental problems around the world is disposal of waste tyres without any purpose. Disposal of waste tyres is an increasing enviromental problem. Also because of high content of valuable chemicals and other compounds hidden in the waste tyres, disposal of them is an economical problem as well. Pyrolysis is a thermochemical process that can be used for recovery of the valuable chemicals in the waste tyre. Pyrolysis is a recycling process in which, liquid product can be used as a fuel directly or can be mixed with petroleum refined oils. Derived gaseous product can also be used as a fuel and solid product can be considered as a fuel and low grade carbon black. In this work, granulated waste tyres have been pyrolyzed in a fixed bed reactor under different conditions of temperature, heating rate and inert purging gas (N2) flow rate. The purpose of the study was to optimize the pyrolysis parameters in order to produce the highest amount of oil. 400°C, 450°C and 500°C were selected and the maximum yield of liquid product was observed at 450°C. Among the heating rates of 10°C/min, 15°C/ min and 20°C/min; 10°C/min was the parameter that gave maximum oil yield. And while working at 450°C and 10°C/min; N2(g) flow rate was examined by using 0.5 L/min, 1 L/min and 1.5 L/min. The maximum oil yield was observed at 1 L N2(g) /min. According to the results of the study; at 450°C, with a heating rate of 10°C/min and 1 L N2(g)/min gave the maximum yield of oil, which is 53.33 wt.%. The pyrolytic oil from waste tyre had the Gross Calorific Value of 42.6 MJ/kg which is very close to that of commercial diesel no 2 (around 42-46 MJ/kg). The pyrolytic oil produced is a promising fuel and can be used as a source of energy after some future work for make it suitable for use in vehicles or in other areas like factories or houses etc.