Sustainable thermal conversion of waste wind turbine blades: Environmental impact and pollutant footprint analysis

The sustainable management of decommissioned wind turbine blades (WTBs) is critical for advancing renewable energy and mitigating environmental impacts. This study evaluates the environmental footprint of vacuum pyrolysis and incineration for WTB treatment, focusing on pollutant formation mechanisms and health risks. We compared the efficiency and environmental impacts of both methods. Results revealed that incineration generated significant hazardous emissions, including toluene (10.58 %, HQ = 2.90) and xylenes (4.05 %, HQ = 55.44) posing severe non-carcinogenic risks. In contrast, vacuum pyrolysis drastically reduced these pollutants (toluene: 2.38 %, HQ = 0.65; xylenes: 1.07 %, HQ = 14.62) with lower health hazards. Specifically, vacuum pyrolysis reduced the emissions of toluene and xylene by 77.50 % and 73.58 %, respectively. Structural characterization confirmed that vacuum pyrolysis preserved fiber integrity while removing 69 % of organic resin. Therefore, vacuum pyrolysis holds certain advantages in the recovery of fibers from WTBs. Molecular dynamics simulations elucidated that pollutant formation (e.g., toluene and xylenes) stemmed from radical-driven Friedel-Crafts alkylation reactions, with incineration exhibiting higher radical diversity and pollutant yields. Compared to nitrogen pyrolysis, vacuum pyrolysis avoided carcinogenic styrene emissions and demonstrated superior cost-effectiveness. The phase analysis further highlighted vacuum pyrolysis' advantages in energy efficiency (36 % recoverable oil) and carbon reduction, despite higher equipment requirements. This study provides mechanistic insights and empirical evidence supporting vacuum pyrolysis as a greener, scalable alternative for WTB recycling, aligning with global sustainability goals.