The rapid expansion of the cumulative installed capacity of wind power in recent years has driven the continuous growth of market demand for wind power operation and maintenance (O&M). Lubricating oil for wind turbine gearboxes is an indispensable and crucial component in O&M. The waste lubricating oil for wind turbine gearboxes is classified as hazardous waste due to its harmful components such as heavy metals and degraded additives. Its efficient recycling and harmless treatment are crucial for achieving clean development in the wind power industry. Firstly, based on the characteristics and composition of waste lubricating oil, the variation laws and underlying causes of typical performance indicators during operating are expounded, including kinematic viscosity, pour point, moisture content, particle contamination level, acid value, and elements (e.g. Fe, P, and S). These variations are primarily induced by factors such as external contamination, oxidation at high temperatures and pressures, and additive degradation. On this basis, the latest research progress in current waste mineral oil regeneration processes is systematically summarized, covering mainstream technical routes such as pretreatment, molecular distillation, solvent extraction, and hydrofining. Furthermore, the feasibility and limitations of the aforementioned methods in extending the service life of waste lubricating oil and realizing its recovery and regeneration are analyzed. The identified limitations include issues such as low treatment efficiency, insufficient processing depth, and restricted application. Finally, the future development directions of high-value waste oils represented by synthetic lubricating oil for wind turbine gearboxes are discussed from the perspectives of industrial development, technological advancement and life management. It emphasizes that establishing a classified recycling system, developing green and efficient regeneration processes, and implementing life management will be the key pathways to realizing a circular economy in the wind power industry.

wind power operation and maintenance  /  gear oil  /  waste oil regeneration