Characteristics of external furnace combustion of used lube oil with different percentages of diethyl ether additives burned with liquefied petroleum gas

The combustion characteristics of used lube oil burned with liquefied petroleum gas (LPG) in an external furnace are experimentally investigated. The external furnace was equipped with a water jacket and with the instrumentation required to monitor the heat released and all related temperatures and flow rates. This study determined the combustion performance as a function of a range of air-to-fuel ratios from 9 to 28 under the effect of different used oil preheating temperatures of 25, 65, and 90 °C, and under the effect of different percentages of added diethyl ether (DEE) of 5, 10, and 20%. Pure used oil and LPG at 25 °C were used in a reference case for comparison. The study results suggest that the combustion of pure used oil with LPG exhibits the highest combustion efficiency at all the different oil preheating temperatures used, corresponding to the highest amount of released heat. For the cases with different DEE percentages, the combustion of the fuel containing 10% DEE additive exhibited the highest efficiency of all percentages, also corresponding to the highest amount of released heat. The findings of this study can be used to improve the efficiency of used oil combustion.