A Review on Global Recovery Policy of Used Lubricating Oils and Their Effects on the Environment and Circular Economy

Abstract

This manuscript underscores the significance of converting and reusing lubricating oils for dual purposes as both lubricants and fuels. This approach not only benefits the environment, but also contributes to the circular economy. To this end, this article conducts a review and delves into the applications and re-refining techniques employed to recover lubricating oil from waste lubricating oil (WLO). A global overview of waste oil recycling and political feasibility in the marketplace is presented, highlighting country-specific preferences for reusing such oils. Moreover, this manuscript analyzes several studies that utilize recycled oil as fuel in thermal equipment, including diesel engines. The findings indicate that CO emissions increased incrementally under both low- (from 3.22% to 21.23%) and high-load conditions (from 6.6% to 18.2%) compared to diesel fuel. Another study reveals that 10% and 20% blends of transformer oil and diesel exhibit lower fuel consumption than diesel fuel at high loads. In all the cases examined, WLO demonstrated slightly higher emission levels than marine diesel oil (MDO), yet lower than those observed with heavy fuel oil (HFO).