Study of the environmental impact of refining used lubricant oils using Life-cycle Assessment methodology as strategy

Used lubricating oil is an anthropogenic pollutant difficult to handle due to its toxicity and physical state. The re-refined process demanded less natural energy resources than non-refined option become it in a sustainable option to the recovery of used lubricating oil. In the present work, a Life Cycle Assessment(LCA)was carried out for the re-refining technology by thin layer distillationin a real process for using the OPENLCA software version 1.11 and the midpoint method of ReCiPe 2016 (H) V1.13. The inventory information was compiled from areal plant and, other part of the information was obtained in dialogue with experts in used oil treatment processes or consulted in specialized sources and extracted from the database Ecoinvent data 3.8. Results were obtained in 10 of the 12 impact categories under study and it was evident that the substitute process flow, to obtain lubricant base, positively impacts avoiding allthe categories studied with values different from zero (results with negative values). The highest environmental impact was associated with the category of climate change with a value of 0.1232 kg CO2-Eq. Furthermore, the most relevant impact to be avoided by the re-refining process is human toxicity with a value of -0.0265 kg 1,4-DCB-Eq. Finally, there-refined processcontributes to preventing environmental impacts in the categories of freshwater ecotoxicity, freshwater eutrophication, marine ecotoxicity, terrestrial ecotoxicity and human toxicity, the latter being the most relevant impact to be avoided.