Recycling waste lubricating oil using two-step pyrolysis and its combustion characterization blended with Jet-A1 in the lean pre-vaporized premixed system

This research investigated waste-lubricating-oil (WLO) recycling using a two-step electrical pyrolysis process and then blended the produced oil with Jet-A1 to explore its combustion features in a lean-pre-vaporized-premixed system. The experiment consisted of two parts. The electrical pyrolysis reactor was initially designed and constructed at a laboratory scale. The WLO was then converted to waste-lubricating-oil-round-2 (WLOR2) using the pyrolysis reactor in two rounds. The physicochemical properties of the produced oil were evaluated using FTIR and TGA. In the second part, the flame temperature profiles of pure Jet-A1 and a blend of 20% by volume WLOR2 and 80% by volume Jet-A1, labeled B20, were evaluated in a lean pre-vaporized premixed system under lean conditions. Results showed that the maximum yield of WLOR2 was around 96.5%, achieved within a temperature range of 280⁓350 °C. The physicochemical properties of the produced oil were comparable to Jet-A1, exhibiting a sulfur content of 0.24 wt.%, a viscosity of 3.34 cSt, a cetane index of 60.8, and a heating value of 42,948 kJ/kg. The flame of the B20 blend demonstrated a wider morphology than pure Jet-A1, attained higher temperatures than Jet-A1 at lower levels, and achieved thermal uniformity comparable to that of Jet-A1 at the combustor output.