Molecular Profile, Fuel Properties, Engine Performance and Emission Characteristics of Gasoline-Like Fuel Produced Via Cracking of Used Engine Oil Using Na-Fe3O4/HZSM-5 Catalyst

Abstract

A vast quantity of used engine oil (UEO) is generated every day and poses a major disposal issue in modern society due to the heavy  metals and other hazardous contaminants present in it. Due to its high carbon content, UEO has great potential to be utilized as a  feedstock for fuel production. The studies on the molecular profile, fuel properties, engine characteristics of gasoline-like fuel produced  via cracking of UEO were conducted. The Fe₃O₄ nanoparticles was synthesized via the one-spot method using iron (III) chloride  hexahydrate (FeCl₃.6H₂O) and iron (II) chloride tetrahydrate (FeCl₂.4H₂O) as precursors, while the HZSM-5 was synthesized using Al₂(SO₄)₃.18H₂O and Na₂SiO₃ as sources of alumina and silica, respectively. The UEO was cracked in a fixed stainless-steel batch reactor  for 1h at varying temperature (350 – 450 ⁰C). The liquid fuel product obtained was analysed for its molecular composition using GC-MS  and FTIR, while ASTM standard procedure was used to determine the fuel properties. The results showed that the catalyst is 97.60%  selective for gasoline range hydrocarbons, which could be attributed to the high surface area of HZSM-5, which offers more active sites  for catalytic cracking. The fuel properties of the produced liquid fuel determined include specific gravity (0.76), kinematic viscosity (1.69  mm2 /Sec), flash point (-42°C), auto ignition temperature (225°C), carbon residue (0.12%), lower heating value (40,443 KJ/kg), and octane number (94). The engine characteristics results of the liquid fuel were comparable to those of commercially available gasoline. Based on  the results obtained, it was concluded that the fuel obtained could be used directly in spark-ignition engines without any negative impact  on engine performance.