Diesel Fuel by Scrap-Tyre Thermal-Mechanical Pyrolysis

Current energy policies are encouraging the near-term use of fuels derived from civil and industrial waste residues, giving new perspectives for their disposal. The possibility of using, in Diesel engines, a liquid fuel derived from waste synthetic polymeric matrices, such as scrap tyres, is evaluated in this paper. The fuel is obtained by means of an innovative technology based on a thermomechanical cracking process at moderate temperatures and pressures. A preliminary investigation was carried out on a 440 cm3 single-cylinder Diesel engine for stationary employ using plain automotive Diesel fuel and two mixtures of automotive Diesel fuel and tyre pyrolysis oil (TPO): the first one containing 20% TPO by volume, the other containing 40% TPO. With the first mixture, test bench results in terms of engine torque, power, specific fuel consumption and exhaust emissions are similar to the ones relative to plain automotive Diesel fuel, whereas the use of the mixture with 40% TPO leads to a general worsening in engine combustion features. Lubricant oil analysis, performed at the end of the tests, shows a certain level of contamination, however without any abnormal decay of lubricant properties. The toxicity levels of the exhaust particulate matter were analysed and result to be the same using plain automotive Diesel fuel and both the mixtures of Diesel fuel and TPO. No meaningful mechanical inconvenience occurred during the engine tests. Nevertheless, long-time reliability of the injection system, as well as of the entire engine, has to be verified